Unconjugated
Forkhead box C2 (Foxc2) protein is a transcription factor in regulation of development, metabolism, and immunology. However, the regulatory mechanisms of Foxc2 on proliferation and apoptosis of preadipocytes are unclear. In this study, we found that high-fat-diet-induced obesity elevated the expression of Foxc2 and cyclin E after 6 weeks. Additionally, Foxc2 suppressed preadipocyte differentiation, increased cell counts and augmented G1-S transition of preadipocytes, along with the elevation of cyclin E expression and the reduction levels of p27 and p53. Furthermore, Foxc2 knockdown reduced early apoptotic cells with accompanying reduction of mitochondrial membrane potential and increased fragmentation of genomic DNA. We show that Foxc2 reduces the expression of Bax, caspase-9, and caspase-3 in both serum-starved and palmitic acid-induced cell apoptotic models, which confirms the anti-apoptotic role of Foxc2. Moreover, the protein kinase B (Akt)/mammalian target of rapamycin (mTOR)C1 signaling pathway and the ERK/mTORC1 signaling pathway were activated along with preadipocyte proliferation in response to Foxc2 overexpression, whereas apoptosis marker genes were downregulated during this process. Those effects were blocked by the interference of Foxc2 or signal pathways specific inhibitors. These data collectively reveal that Foxc2 enhances proliferation of preadipocytes and inhibits apoptosis of preadipocytes by activating the Akt/mTORC1 and ERK/mTORC1 signaling pathways.
Despite a variety of novel therapeutic agents, such as bortezomib, thalidomide and topotecan, multiple myeloma (MM) remains an incurable disease, thus the development of new chemotherapeutical agents is of high priority. We found HM910, a novel camptothecin (CPT) derivative, exhibited potent inhibition of MM cell growth in vitro and in xenografts of nude mice. Mechanistically, HM910 reduced the mitochondrial transmembrane potential (ΔΨm) via an increase in reactive oxygen species (ROS), which eventually resulting in the release of cytochrome c and the activation of mitochondrial-dependent apoptotic pathway. On the other hand, HM910 significantly triggered cell cycle arrest in G1 phase via downregulating the expressions of cyclin dependent kinase (CDK) 4 and 6, resulting in down-regulation of cyclin D1. Therefore, HM910 maybe a promising candidate for treating MM patients and is currently in phase I clinical trial in China.
Oncolytic virotherapy is a growing treatment modality that uses replicating viruses as selective antineoplastic agents. Safety and efficacy considerations dictate that an ideal oncolytic agent would discriminate between normal and cancer cells on the basis of common genetic abnormalities in human cancers. Here, we identify a naturally occurring alphavirus (M1) as a novel selective killer targeting zinc-finger antiviral protein (ZAP)-deficient cancer cells. In vitro, in vivo, and ex vivo studies showed potent oncolytic efficacy and high tumor tropism of M1. We showed that the selectivity depends on ZAP deficiency by systematic identification. A large-scale multicenter pathology study using tissue microarrays reveals that ZAP is commonly deficient in human cancers, suggesting extensive application prospects for M1. Additionally, M1 killed cancer cells by inducing endoplasmic reticulum stress-mediated apoptosis. Our report provides novel insights into potentially personalized cancer therapy using oncolytic viruses.
The goal of this study was to investigate the possible protective effects of sitagliptin against dyslipidemia-related kidney injury in apolipoprotein E knockout (apoE-/-) mice. Eight-week-old male apoE-/- mice were randomized to receive either a high fat diet (HFD, apoE-/- group) or HFD mixed with sitagliptin (sita + apoE-/- group) for 16 weeks. A control group of age- and gender-matched C57BL/6J mice were fed a HFD. The apoE-/- group exhibited increases in body weight and serum lipid levels in addition to high-density lipoprotein, and increases in 24-h urinary 8-hydroxy-2-deoxyguanosine and albuminuria excretion. Decreased insulin sensitivity was also observed in the apoE-/- group. These mice additionally contained enlargements of the glomerular mesangial matrix area, lipid deposition area, and renal interstitium collagen area. The apoE-/- group also demonstrated down-regulation of phosphorylated AMP-activated protein kinase (AMPK), increases in renal mRNA expression of transforming growth factor-beta 1 (TGF-β1) and fibronectin (FN), and increased protein expression of Akt, TGF-β1, FN and p38/ERK mitogen-activated protein kinase (MAPK). Sitagliptin treatment successfully ameliorated all the deleterious effects of dyslipidemia tested. To our knowledge, this is the first time that sitagliptin has been shown to reverse the renal dysfunction and structural damage induced by dyslipidemia in apoE-/- mice. Our results suggest that the renoprotective mechanism of sitagliptin may be due to a reduction in Akt levels, a restoration of AMPK activity, and inhibition of TGF-β1, FN, and p38/ERK MAPK signaling pathways.
Our previous studies have shown that an active fragment of human tachykinins (hHK-1(4-11)) produced an opioid-independent analgesia after intracerebroventricular (i.c.v.) injection in mice, which has been markedly enhanced by a δ OR antagonist, naltrindole hydrochloride (NTI). In this study, we have further characterized the in vivo analgesia after i.c.v. injection of hHK-1(4-11) in mouse model. Our qRT-PCR results showed that the mRNA levels of several ligands and receptors (e.g. PPT-A, PPT-C, KOR, PDYN and PENK) have not changed significantly. Furthermore, neither transcription nor expression of NK1 receptor, MOR and POMC have changed noticeably. In contrast, both mRNA and protein levels of DOR have been up-regulated significantly, indicating that the enhanced expression of δ opioid receptor negatively modulates the analgesia induced by i.c.v. injection of hHK-1(4-11). Additionally, the combinatorial data from our previous and present experiments strongly suggest that the discriminable distribution sites in the central nervous system between hHK-1(4-11) and r/mHK-1 may be attributed to their discriminable analgesic effects. Altogether, our findings will not only contribute to the understanding of the complicated mechanisms regarding the nociceptive modulation of hemokinin-1 as well as its active fragments at supraspinal level, but may also lead to novel pharmacological interventions.
Bone morphogenetic protein 2 (BMP2) is one of the key chondrogenic growth factors involved in the cartilage regeneration. However, it also exhibits osteogenic abilities and triggers endochondral ossification. Effective chondrogenesis and inhibition of BMP2-induced osteogenesis and endochondral ossification can be achieved by directing the mesenchymal stem cells (MSCs) towards chondrocyte lineage with chodrogenic factors, such as Sox9. Here we investigated the effects of Sox9 on BMP2-induced chondrogenic and osteogenic differentiation of MSCs. We found exogenous overexpression of Sox9 enhanced the BMP2-induced chondrogenic differentiation of MSCs in vitro. Also, it inhibited early and late osteogenic differentiation of MSCs in vitro. Subcutaneous stem cell implantation demonstrated Sox9 potentiated BMP2-induced cartilage formation and inhibited endochondral ossification. Mouse limb cultures indicated that BMP2 and Sox9 acted synergistically to stimulate chondrocytes proliferation, and Sox9 inhibited BMP2-induced chondrocytes hypertrophy and ossification. This study strongly suggests that Sox9 potentiates BMP2-induced MSCs chondrogenic differentiation and cartilage formation, and inhibits BMP2-induced MSCs osteogenic differentiation and endochondral ossification. Thus, exogenous overexpression of Sox9 in BMP2-induced mesenchymal stem cells differentiation may be a new strategy for cartilage tissue engineering.
Interleukin (IL)-35 is a newly identified immune negative molecule which is secreted by CD4(+)Foxp3(+) T regulatory cells (Tregs) and contributes to their suppressive capacity. Early data have shown that IL-35 inhibits development of several autoimmune diseases. However, the role of IL-35 in atherosclerosis, a lipid-driven chronic inflammatory disease in arterial wall, remains to be investigated. Here, we found that IL-35 was involved in atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice. ApoE(-/-) mice with established atherosclerotic lesion displayed a lower level of IL-35 compared to age-matched wild type C57BL/6 mice without plaque. However, IL-35 expression increased significantly in ApoE(-/-) mice with attenuated plaque. More importantly, we found that modulation of ER stress treated by chemical chaperone, 4-Phenyl butyric acid (PBA) in vivo, mainly upregulated immune negative regulating molecule IL-35, as well as IL-10 and Foxp3, accompanied by increased Tregs. However, no obvious impact on pro-inflammatory molecules such as TNF-α, IFN-γ, IL-17 and IL-23 was observed, which provides new insight into the benefit of ER stress recovery from attenuated plaque. Our results suggest that IL-35 might have a potential value for atherosclerotic therapy.
Photodynamic therapy (PDT) is a regulatory-approved modality for treating a variety of malignant tumors. It induces tumor tissue damage via photosensitizer-mediated oxidative cytotoxicity. The heat shock protein 70 (HSP70-1) is a stress protein encoded by the HSPA1A gene and is significantly induced by oxidative stress associated with PDT. The aim of this study was to identify the functional region of the HSPA1A promoter that responds to PDT-induced oxidative stress and uses the stress responsiveness of HSPA1A expression to establish a rapid and cost-effective photocytotoxic assessment bioassay to evaluate the photodynamic potential of photosensitizers. By constructing luciferase vectors with a variety of hspa1a promoter fractions and examining their relative luciferase activity, we demonstrated that the DNA sequence from -218 to +87 of the HSPA1A gene could be used as a functional promoter to detect the PDT-induced oxidative stress. The maximal relative luciferase activity level of HSPA1A (HSP70-1) induced by hypericin-PDT was nearly nine times that of the control. Our results suggest that the novel reporter gene assay using a functional region of the HSP70A1A promoter has significant advantages for the detection of photoactivity in terms of both speed and sensitivity, when compared with a cell viability test based on ATP quantification and ROS levels. Furthermore, phthalocyanine zinc and methylene blue both induced significantly elevated levels of relative luciferase activity in a dose-dependent manner.
BACKGROUND:
Gold nanoparticles (GNPs) can potentially be used in biomedical fields ranging from therapeutics to diagnostics, and their use will result in increased human exposure. Many studies have demonstrated that GNPs can be deposited in the kidneys, particularly in renal tubular epithelial cells. Chronic hypoxic is inevitable in chronic kidney diseases, and it results in renal tubular epithelial cells that are susceptible to different types of injuries. However, the understanding of the interactions between GNPs and hypoxic renal tubular epithelial cells is still rudimentary. In the present study, we characterized the cytotoxic effects of GNPs in hypoxic renal tubular epithelial cells.
RESULTS:
Both 5 nm and 13 nm GNPs were synthesized and characterized using various biophysical methods, including transmission electron microscopy, dynamic light scattering, and ultraviolet-visible spectrophotometry. We detected the cytotoxicity of 5 and 13 nm GNPs (0, 1, 25, and 50 nM) to human renal proximal tubular cells (HK-2) by Cell Counting Kit-8 assay and lactate dehydrogenase release assay, but we just found the toxic effect in the 5 nm GNP-treated cells at 50 nM dose under hypoxic condition. Furthermore, the transmission electron microscopy images revealed that GNPs were either localized in vesicles or free in the lysosomes in 5 nm GNPs-treated HK-2 cells, and the cellular uptake of the GNPs in the hypoxic cells was significantly higher than that in normoxic cells. In normoxic HK-2 cells, 5 nm GNPs (50 nM) treatment could cause autophagy and cell survival. However, in hypoxic conditions, the GNP exposure at the same condition led to the production of reactive oxygen species, the loss of mitochondrial membrane potential (ΔΨM), and an increase in apoptosis and autophagic cell death.
CONCLUSION/SIGNIFICANCE:
Our results demonstrate that renal tubular epithelial cells presented different responses under normoxic and hypoxic environments, which provide an important basis for understanding the risks associated with GNP use-especially for the potential GNP-related therapies in chronic kidney disease patients.
BACKGROUND:
The epithelial-to-mesenchymal transition (EMT) is a key process in carcinogenesis, invasion, and metastasis of oral squamous cell carcinoma (OSCC). In our previous studies, we found that neuropilin-1 (NRP1) is overexpressed in tongue squamous cell carcinoma and that this overexpression is associated with cell migration and invasion. Nuclear factor-kappa B (NF-κB) plays an essential role both in the induction and the maintenance of EMT and tumor metastasis. Therefore, we hypothesized that NRP1 induces EMT, and that NRP1-induced migration and invasion may be an important mechanism for promoting invasion and metastasis of OSCC through NF-κB activation.
METHODS/RESULTS:
The variations in gene and protein expression and the changes in the biological behavior of OSCC cell lines transfected with a vector encoding NRP1, or the corresponding vector control, were evaluated. NRP1 overexpression promoted EMT and was associated with enhanced invasive and metastatic properties. Furthermore, the induction of EMT promoted the acquisition of some cancer stem cell (CSC)-like characteristics in OSCC cells. We addressed whether selective inhibition of NF-κB suppresses the NRP1-mediated EMT by treating cells with pyrrolidinedithiocarbamate ammonium (PDTC), an inhibitor of NF-κB. Immunohistochemical analysis of NRP1 in OSCC tissue samples further supported a key mediator role for NRP1 in tumor progression, lymph node metastasis, and indicated that NRP1 is a predictor for poor prognosis in OSCC patients.
CONCLUSION:
Our results indicate that NRP1 may regulate the EMT process in OSCC cell lines through NF-κB activation, and that higher NRP1 expression levels are associated with lymph node metastasis and poor prognosis in OSCC patients. Further investigation of the role of NRP1 in tumorigenesis may help identify novel targets for the prevention and therapy of oral cancers.
AIM:
To investigate the mechanisms of how cyclooxygenase-2 (COX-2) regulates E-cadherin in gastric cancer cells.
METHODS:
COX-2 expression in human gastric cancer cell lines SGC-7901, BGC-823, MGC-803 and AGS were measured at the mRNA and protein level. COX-2 rich cell line SGC-7901 was chosen for subsequent experiments. siRNA mediated gene knockdown was used to investigate the impact of COX-2 on nuclear factor-κB (NF-κB), Snail, and E-cadherin in gastric cancer cells. Gene expression was determined by Western blot and real-time polymerase chain reaction. To analyze whether NF-κB inhibition could interrupt the modulatory effect of COX-2 or prostaglandin E2 (PGE2) on E-cadherin, gastric cancer cells were treated with celecoxib or PGE2, in the presence of NF-κB specific siRNA.
RESULTS:
Highest expression level of COX-2 was found in SGC-7901 cells, both at mRNA and protein levels. siRNA mediated down-regulation of COX-2 led to a reduced expression of NF-κB and Snail, but an increased expression of E-cadherin in SGC-7901 cells. siRNA mediated down-regulation of NF-κB also led to a reduced expression of E-cadherin and Snail in SGC-7901 cells. However, COX-2 expression did not alter after cells were treated with NF-κB specific siRNA in SGC-7901 cells. Treatment of SGC-7901 cells with celecoxib led to a reduced expression of Snail but an increased expression of E-cadherin. In contrast, treatment of SGC-7901 cells with PGE2 led to an increased Snail and a decreased E-cadherin. However, siRNA-mediated knockdown of NF-κB partially abolished the effect of celecoxib and PGE2 on the regulation of E-cadherin and Snail in SGC-7901 cells.
CONCLUSION:
COX-2 likely functions upstream of NF-κB and regulates the expression of E-cadherin via NF-κB/Snail signaling pathway in gastric cancer cells.
BACKGROUND:
MicroRNAs are regulators that can play an essential role in tumorigenesis. Although miR-302 families have been suggested to be tumor repressors in human cancer, the mechanism by which they suppress tumor development remains to be defined. In this study, we discover that miR302b suppresses tumor proliferation may due to directly targeting EGFR in human hepatocellular carcinoma (HCC).
METHODS:
QRT-PCR was used to assess miR-302b and EGFR expression in 27 pairs of clinical hepatocellular carcinoma tissues and their corresponding adjacent nontumorous liver tissues. MTT, colony formation, immunofluorescence staining, and cell cycle assays were used to examine the tumor suppressor role of miR302b in cell proliferation. Luciferase assays were performed to assess the EGFR was a novel target of miR-302b. Western blot assay was used to validate the protein expression level.
RESULTS:
We demonstrated that miR-302b was frequently down-regulated, whereas EGFR was up-regulated in 27 pairs of clinical HCC and non-tumorous counterparts. The dual-luciferase reporter assays revealed that EGFR was a novel target of miR-302b. Re-expression of miR-302b resulted in the inhibition of proliferation in hepatocellular carcinoma SMMC-7721 cells. The silencing of EGFR by miR-302b or siEGFR led to down-regulation of proliferation-related proteins, such as AKT2, CCND1, and CDK2.
CONCLUSION:
miR-302b suppresses HCC growth may due to targeting the EGFR/AKT2/CCND1 pathway.
Cisplatin, a highly effective and widely used chemotherapeutic agent, has a major limitation for its nephrotoxicity. We recently identified a novel strategy for attenuating its nephrotoxicity in chemotherapy by an effective adjuvant via epigenetic modification through targeting HDAC2. Molecular docking and SPR assay firstly reported that 18βGA, major metabolite of GA, could directly bind to HDAC2 and inhibit the activity of HDAC2. The effects and mechanisms of GA and 18βGA were assessed in CP-induced AKI in C57BL/6 mice, and in CP-treated HK-2 and mTEC cells lines. TUNEL and FCM results confirmed that GA and 18βGA could inhibit apoptosis of renal tubular epithelial cells induced by CP in vivo and in vitro. Western blot and immunofluorescence results demonstrated that the expression of BMP-7 was clearly induced by 18βGA in AKI models while siRNA BMP-7 could reduce the inhibitory effect of 18βGA on apoptosis. Results of current study indicated that 18βGA inhibited apoptosis of renal tubular epithelial cells via enhancing the level of BMP-7 epigenetically through targeting HDAC2, therefore protecting against CP-induced AKI. These available evidence, which led to an improved understanding of molecular recognition, suggested that 18βGA could serve as a potential clinical adjuvant in chemotherapy.
A fundamental element of acute lung injury (ALI) is the inflammation that is part of the body's immune response to a variety of local or systemic stimuli. Lipoxins (LXs) are important endogenous lipids that mediate resolution of inflammation. Previously, we demonstrated that LXA4 reduced the LPS inhalation-induced pulmonary edema, neutrophil infiltration and TNF-α production in mice. With the same model, the current investigation focused on the role of the airway epithelium, a first-line barrier and a prime target of inhaled toxicants. We report that LXA4 strongly inhibited LPS-induced ALI in mice, in part by protecting the airway epithelium and preserving the E-cadherin expression and airway permeability. Using a cryo-imaging assay and fluorescence detection, LXA4 was shown to block LPS-induced ROS generation and preserve mitochondrial redox status both in vivo and in vitro. To further assess whether and how NF-E2-related factor 2 (Nrf2) was involved in the protective effect of LXA4, fluorescence resonance energy transfer (FRET) analysis was employed in human epithelial cell line (16HBE), to determine the relative distance between Nrf2 and its negative regulator or cytosolic inhibitor, Kelch-like ECH-associated protein 1 (Keap1). It provided us the evidence that LXA4 further promoted the dissociation of Nrf2 and Keap1 in LPS-treated 16HBE cells. The results also showed that LXA4 activates Nrf2 by phosphorylating it on Ser40 and triggering its nuclear translocation. Moreover, when the plasmid expression dominant negative mutation of Nrf2 was transfected as an inhibitor of wild-type Nrf2, the protective effect of LXA4 on E-cadherin expression was almost completely blocked. These results provide a new mechanism by which LXA4 inhibits LPS-induced ALI through Nrf2-mediated E-cadherin expression.
Polycystic ovarian syndrome (PCOS) is associated with hyperhomocysteinemia and polycystic ovaries (PCO) usually produce oocytes of poor quality. However, the intracellular mechanism linking hyperhomocysteinemia and oocyte quality remains elusive. In this study, the quality of the oocytes isolated from healthy and polycystic gilt ovaries was evaluated in vitro in association with one-carbon metabolism, mitochondrial DNA (mtDNA) methylation, and mitochondrial function. PCO oocytes demonstrated impaired polar body extrusion, and significantly decreased cleavage and blastocyst rates. The mitochondrial distribution was disrupted in PCO oocytes, together with decreased mitochondrial membrane potential and deformed mitochondrial structure. The mtDNA copy number and the expression of mtDNA-encoded genes were significantly lower in PCO oocytes. Homocysteine concentration in follicular fluid was significantly higher in PCO group, which was associated with significantly up-regulated one-carbon metabolic enzymes betaine homocysteine methyltransferase (BHMT), glycine N-methyltransferase (GNMT) and the DNA methyltransferase DNMT1. Moreover, mtDNA sequences coding for 12S, 16S rRNA and ND4, as well as the D-loop region were significantly hypermethylated in PCO oocytes. These results indicate that an abnormal activation of one-carbon metabolism and hypermethylation of mtDNA may contribute, largely, to the mitochondrial malfunction and decreased quality of PCO-derived oocytes in gilts.
Lysophosphatidylcholine (LPC) induces inflammation in endothelial cells (ECs) but the mechanism is not fully understood. The Notch signaling pathway is involved in chronic EC inflammation, but its functions in LPC-induced endothelial inflammatory damage and 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside's (TSG) protective effect during LPC-induced inflammatory damage in human umbilical vein endothelial cells (HUVECs) is largely unknown. We report that Notch signaling activation contributed to LPC-induced injury in HUVECs, and that TSG protected HUVECs from LPC-induced injury by antagonizing Notch signaling activation by LPC. γ-secretase inhibitor (DAPT), a specific inhibitor of the Notch signaling pathway, and Notch1 siRNA were used to inhibit Notch activity. HUVECs were exposed to LPC in the presence or absence of TSG, DAPT, and Notch1 siRNA. LPC treatment of HUVECs resulted in reduced cell viability, and Notch1 and Hes1 upregulation. Either silencing of Notch1 by siRNA or pharmacological inhibition of Notch signaling by DAPT prevented the loss of cell viability, and induction of apoptosis, and enhanced expression Notch1, Hes1 and MCP-1 by LPC in HUVECs. Similarly, TSG reduced LPC stimulation of Notch1, Hes1, and MCP-1 expression, prevented the release of IL-6 and CRP and rescued HUVECs from LPC-induced cell damage. Our data indicate that the Notch signaling pathway is a crucial mediator of endothelial inflammatory damage and that TSG protects against endothelial inflammatory damage by inhibiting the Notch signaling pathway. Our findings suggest that targeting Notch signaling by natural products such as TSG is a promising strategy for the prevention and treatment of chronic inflammation associated diseases, including atherosclerosis.
© 2015 IUBMB Life, 68(1):37-50, 2016.
Accumulating evidences demonstrated that statins impaired glucose utilization. This study was aimed to investigate whether PXR was involved in the atorvastatin-impaired glucose utilization. Rifampicin/PCN served as PXR activator control. Glucose utilization, glucose uptake, protein levels of GLUT2, GCK, PDK2, PEPCK1 and G6Pase in HepG2 cells were measured. PXR inhibitors, PXR overexpression and PXR siRNA were applied to verify the role of PXR in atorvastatin-impaired glucose utilization in cells. Hypercholesterolemia rats induced by high fat diet feeding, orally received atorvastatin (5 and 10 mg/kg), pravastatin (10 mg/kg) for 14 days, or intraperitoneally received PCN (35 mg/kg) for 4 days. Results showed that glucose utilization was markedly inhibited by atorvastatin, simvastatin, pitavastatin, lovastatin and rifampicin. Neither rosuvastatin nor pravastatin showed the similar effect. Atorvastatin and pravastatin were selected for the following study. Atorvastatin and rifampicin significantly inhibited glucose uptake and down-regulated GLUT2 and GCK expressions. Similarly, overexpressed PXR significantly down-regulated GLUT2 and GCK expressions and impaired glucose utilization. Ketoconazole and resveratrol attenuated the impaired glucose utilization by atorvastatin and rifampicin in both parental and overexpressed PXR cells. PXR knockdown significantly up-regulated GLUT2 and GCK proteins and abolished the decreased glucose consumption and uptake by atorvastatin and rifampicin. Animal experiments showed that atorvastatin and PCN significantly elicited postprandial hyperglycemia, leading to increase in glucose AUC. Expressions of GLUT2 and GCK in rat livers were markedly down-regulated by atorvastatin and PCN. In conclusion, atorvastatin impaired glucose utilization in hepatocytes via repressing GLUT2 and GCK expressions, which may be partly due to PXR activation.
Antagonizing MDM2 and MDMX to activate the tumor suppressor protein p53 is an attractive therapeutic paradigm for the treatment of glioblastoma multiforme (GBM). However, challenges remain with respect to the poor ability of p53 activators to efficiently cross the blood-brain barrier and/or blood-brain tumor barrier and to specifically target tumor cells. To circumvent these problems, we developed a cyclic RGD peptide-conjugated poly(ethylene glycol)-co-poly(lactic acid) polymeric micelle (RGD-M) that carried a stapled peptide antagonist of both MDM2 and MDMX (sPMI). The peptide-carrying micelle RGD-M/sPMI was prepared via film-hydration method with high encapsulation efficiency and loading capacity as well as ideal size distribution. Micelle encapsulation dramatically increased the solubility of sPMI, thus alleviating its serum sequestration. In vitro studies showed that RGD-M/sPMI efficiently inhibited the proliferation of glioma cells in the presence of serum by activating the p53 signaling pathway. Further, RGD-M/sPMI exerted potent tumor growth inhibitory activity against human glioblastoma in nude mouse xenograft models. Importantly, the combination of RGD-M/sPMI and temozolomide--a standard chemotherapy drug for GBM increased antitumor efficacy against glioblastoma in experimental animals. Our results validate a combination therapy using p53 activators with temozolomide as a more effective treatment for GBM.
Matrix metalloproteinases (MMPs) play an active role in facilitating the invasion of cancer cells with excessive extracellular matrix (ECM) degradation. In the present study, we investigated the antiinvasive effects of isorhamnetin, a naturally occurring flavonoid, on MDA-MB-231 human breast carcinoma cells. The results indicated that isorhamnetin significantly inhibited the adhesion, migration, and invasion of the cells in vitro. Moreover, isorhamnetin suppressed the activity and expression of MMP-2 and MMP-9, which were determined by gelatin zymography, real-time PCR, and Western blot analysis, respectively. Besides, isorhamnetin had little effect on the secretion of urokinase plasminogen activator. Further elucidation of the mechanism revealed that isorhamnetin exerted an inhibitory effect on the phosphorylation of p38 and STAT3, although it had no effect on ERK1/2 and JNK. Taken together, these data demonstrated that isorhamnetin could significantly inhibit the invasion of MDA-MB-231 cells by downregulating the expression and activity of MMP-2 and MMP-9, which was potentially associated with the suppression of p38 MAPK and STAT3. Therefore, the findings provide new evidence for the anti-cancer activity of isorhamnetin.
Evidence has shown that the activation of the autophagy pathway after experimental subarachnoid hemorrhage (SAH) protects against neuronal damage. Tert-butylhydroquinone (tBHQ), a commonly used nuclear factor erythroid 2-related factor 2 (Nrf2) activator, was found to significantly enhance autophagy activation. The aim of this study was to explore the effect of tBHQ treatment on early stage brain injury at 24 h after SAH. The results showed that tBHQ treatment failed to stimulate an effective anti-oxidative effect at 24 h after the SAH operation, but succeeded in ameliorating early brain injury, including alleviated brain edema, BBB disruption, neuronal degeneration and neurological deficits. Further exploration found that tBHQ treatment significantly increased the expression of Beclin-1 and the ratio of microtubule-associated protein 1 light chain 3 (LC3)-II to LC3-I, suggesting that autophagy was enhanced after tBHQ treatment. Moreover, tBHQ treatment restored Bcl-2 and Bax expression and reduced caspase-3 cleavage, suggesting the protective effect of tBHQ treatment in ameliorating brain injury after SAH. Furthermore, tBHQ enhanced autophagy activation, decreased neuronal degeneration and improved the neurological score after SAH in Nrf2-deficient mice. Taken together, these findings suggest that tBHQ treatment exerts neuro-protective effects against EBI following SAH by enhancing Nrf2-independent autophagy. Therefore, tBHQ is a promising therapeutic agent against EBI following SAH.
We investigated potential mechanisms of acute injury in pubertal mice testes after exposure to carbon ion radiation (CIR). Serum testosterone was measured following whole-body irradiation with a 2Gy carbon ion beam. Comparative proteomic profiling and Western blotting were applied to identify potential biomarkers and measure protein expression, and terminal dUTP nick end-labeling (TUNEL) was performed to detect apoptotic cells. Immunohistochemistry and immunofluorescence were used to investigate protein localization. Serum testosterone was lowest at 24h after CIR, and 10 differentially expressed proteins were identified at this time point that included eIF4E, an important regulator of initiation that combines with mTOR and 4EBP1 to control protein synthesis via the mTOR signaling pathway during proliferation and apoptosis. Protein expression and localization studies confirmed their association with acute injury following exposure to CIR. These three proteins may be useful molecular markers for detecting abnormal spermatogenesis following exposure to environmental and therapeutic radiation.
A putative etiological association exists between noise exposure and Alzheimer's disease (AD). Amyloid-β (Aβ) pathology is thought to be one of the primary initiating factors in AD. It has been further suggested that subsequent dysregulation of Aβ may play a mechanistic role in the AD-like pathophysiology associated with noise exposure. Here, we used ELISA, immunoblotting, cytokine arrays, and RT-PCR, to examine both hippocampal Aβ pathology and neuroinflammation in rats at different time points after noise exposure. We found that chronic noise exposure significantly accelerated the progressive overproduction of Aβ, which persisted for 7 to 14 days after the cessation of exposure. This effect was accompanied by up-regulated expression of amyloid precursor protein (APP) and its cleavage enzymes, β- and γ-secretases. Cytokine analysis revealed that chronic noise exposure increased levels of tumor necrosis factor-α and the receptor for advanced glycation end products, while decreasing the expression of activin A and platelet-derived growth factor-AA. Furthermore, we found persistent elevations of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 expression that closely corresponded to the noise-induced increases in Aβ and neuroinflammation. These studies suggest that lifelong environmental noise exposure may have cumulative effects on the onset and development of AD.
The chromosome-centric human proteome project (C-HPP) has made great progress of finding protein evidence (PE) for missing proteins (PE2-4 proteins defined by the neXtProt), which now becomes an increasingly challenging field. As a majority of samples tested in this field were from adult tissues/cells, the developmental stage specific or relevant proteins could be missed due to biological source availability. We posit that epigenetic interventions may help to partially bypass such a limitation by stimulating the expression of the "silenced" genes in adult cells, leading to the increased chance of finding missing proteins. In this study, we established in vitro human cell models to modify the histone acetylation, demethylation, and methylation with near physiological conditions. With mRNA-seq analysis, we found that histone modifications resulted in overall increases of expressed genes in an even distribution manner across different chromosomes. We identified 64 PE2-4 and six PE5 proteins by MaxQuant (FDR < 1% at both protein and peptide levels) and 44 PE2-4 and 7 PE5 proteins by Mascot (FDR < 1% at peptide level) searches, respectively. However, only 24 PE2-4 and five PE5 proteins in Mascot, and 12 PE2-4 and one PE5 proteins in MaxQuant searches could, respectively, pass our stringently manual spectrum inspections. Collectively, 27 PE2-4 and five PE5 proteins were identified from the epigenetically modified cells; among them, 19 PE2-4 and three PE5 proteins passed FDR < 1% at both peptide and protein levels. Gene ontology analyses revealed that the PE2-4 proteins were significantly involved in development and spermatogenesis, although their chemical-physical features had no statistical difference from the background. In addition, we presented an example of suspicious PE5 peptide spectrum matched with unusual AA substitutions related to post-translational modification. In conclusion, the epigenetically manipulated cell models should be a useful tool for finding missing proteins in C-HPP. The mass spectrometry data have been deposited to the iProx database (accession number: IPX00020200).
Quercetin is a classic flavonoid that inhibits the epithelial-mesenchymal transition (EMT) of tumor cells. However, the effects of quercetin on the EMT of renal tubular epithelial cells, a potential mechanism of renal fibrosis and important characteristic of diabetic nephropathy (DN), remain largely unknown. In the present study, we investigated the effects of quercetin on the EMT of two lines of renal tubular proximal epithelial cells (HK-2 and NRK-52E) induced with high glucose and renal fibrosis resulting from type 1 diabetes and tried to clarify the specific mechanisms underlying these effects. The in vitro results showed that the EMT of HK-2 and NRK-52E cells was induced by high glucose, and mTORC1/p70S6K was highly activated in these two cell lines cultured under high glucose. Quercetin effectively ameliorated the high glucose-induced EMT of HK-2 and NRK-52E cells and inhibited the activation of mTORC1/p70S6K. In vivo, diabetic rats showed a significant decline in renal function and severe renal fibrosis at 14 weeks after STZ injection. Furthermore, mTORC1/p70S6K was activated in the renal cortex of diabetic rats. Treatment with quercetin alleviated the decline in renal function, and the progression of renal fibrosis and inhibited mTORC1/p70S6K activation in the diabetic renal cortex. In addition, we examined the protein and mRNA levels of four transcriptional factors (snail, slug, twist and ZEB-1), which regulate E-cadherin expression at the transcriptional level both in vivo and in vitro. The results revealed that the elevated expression of snail and twist in HK-2 and NRK-52E cells cultured under high glucose and in the renal cortex of diabetic rats was inhibited by quercetin. These results demonstrated that quercetin ameliorates the EMT of HK-2 and NRK-52E cells induced by high glucose and renal fibrosis induced by diabetes, and these effects have been associated with the inhibition of the two transcriptional factors (snail and twist) and the activation of mTORC1/p70S6K.
α-Lipoic acid (LA) has been demonstrated to be a key regulator of energy metabolism. However, whether LA can protect the liver from inflammation, as well as the underlying mechanism involved, are still largely unclear. In the present study, mice treated with lipopolysaccharide (LPS) and injected with LA were used as a model. Liver injury, energy metabolism and mitochondrial regulation were investigated to assess the protective effect of LA on the liver and explore the possible mechanisms involved. Our results showed that LA attenuated liver injury, as evidenced by the decreased plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels after LA treatment compared with the LPS-treated group. The hepatic ATP and NADH levels, expression levels of most mitochondrial DNA (mtDNA)-encoded genes as well as mitochondrial complex I, IV and V activities were all significantly increased in the LA-treated group compared with the LPS-treated group. Levels of Sirt3 protein, which is essential for the regulation of mitochondrial metabolism, were also increased in the LA-treated group. Regarding the regulation of mtDNA-encoded genes expression, we observed no obvious change in the methylation status of the mtDNA D-loop region. However, compared to the LPS-treated group, LA treatment increased glucocorticoid receptor (GR) protein expression in the liver, as well as the level of GR occupancy on the mtDNA D-loop region. Our study demonstrates that LA exerts a liver-protective effect in an inflammation state by improving mitochondrial function. Furthermore, to the best of our knowledge, we demonstrate for the first time that GR may be involved in this effect via an enhanced binding to the mtDNA transcriptional control region, thereby regulating the expression of mtDNA-encoded genes.
Pregnane X receptor (PXR) activation exhibits anti-inflammatory effects via repressing nuclear factor-κB (NF-κB); however, its overactivation may disrupt homeostasis of various enzymes and transporters. Here we found that ginsenosides restore PXR/NF-κB signaling in inflamed conditions without disrupting PXR function in normal conditions. The effects and mechanisms of ginsenosides in regulating PXR/NF-κB signals were determined both in vitro and in vivo. Ginsenosides significantly inhibited NF-κB activation and restored the expression of PXR target genes in tumor necrosis factor-α-stimulated LS174T cells. Despite not being PXR agonists, ginsenosides repressed NF-κB activation in a PXR-dependent manner. Ginsenosides significantly increased the physical association between PXR and the NF-κB p65 subunit and thereby decreased the nuclear translocation of p65. Ginsenoside Rb1 and compound K (CK) were major bioactive compounds in the regulating PXR/NF-κB signaling. Consistently, ginsenosides significantly attenuated dextran sulfate sodium-induced experimental colitis, which was associated with restored PXR/NF-κB signaling. This study indicates that ginsenosides may elicit anti-inflammatory effects via targeting PXR/NF-κB interaction without disrupting PXR function in healthy conditions. Ginsenoside Rb1 and CK may serve as leading compounds in the discovery of new drugs that target PXR/NF-κB interaction in therapy for inflammatory bowel disease.
FTY720 is a potent immunosuppressant which has preclinical antitumor efficacy in various cancer models. However, its role in glioblastoma remains unclear. In the present study, we found that FTY720 induced extrinsic apoptosis, necroptosis and autophagy in human glioblastoma cells. Inhibition of autophagy by either RNA interference or chemical inhibitors attenuated FTY720-induced apoptosis and necrosis. Furthermore, autophagy, apoptosis and necrosis induction were dependent on reactive oxygen species-c-Jun N-terminal kinase-protein 53 (ROS-JNK-p53) loop mediated phosphatidylinositide 3-kinases/protein kinase B/mammalian target of rapamycin/p70S6 kinase (PI3K/AKT/mTOR/p70S6K) pathway. In addition, receptor-interacting protein 1 and 3 (RIP1 and RIP3) served as an upstream of ROS-JNK-p53 loop. However, the phosphorylation form of FTY720 induced autophagy but not apoptosis and necroptosis. Finally, the in vitro results were validated in vivo in xenograft mouse of glioblastoma cells. In conclusion, the current study provided novel insights into understanding the mechanisms and functions of FTY720-induced apoptosis, necroptosis and autophagy in human glioblastoma cells.
Compared with normal differentiated cells, cancer cells take up much more glucose and metabolize it mainly via aerobic glycolysis. This metabolic phenotype is characterized with high expression of glucose transporters (Gluts) and pyruvate kinase M2 (PKM2). Glucose regulated protein 78 (GRP78) is a glucose-sensing protein and frequently up-regulated in cancer cells, however, whether it is directly implicated in glucose metabolism remains to be elucidated. Here we report that upon glucose deficiency, the induction of GRP78 resulted in enhanced HIF-1α transcription, accompanied by a transient increased expression of Glut-1. In addition, GRP78 was likely to facilitate the membrane translocation of Glut-1 via protein-protein interaction. Glucose starvation-stimulated GRP78 also impaired the expression of PKM2 but promoted the expression of mitochondrial pyruvate dehydrogenase A (PDHA) and B (PDHB), resulting in the metabolic shift from glycolysis to the TCA cycle. Interestingly, the inhibition of PKM2 by GRP78 was abrogated when glucose supply was restored, suggesting that GRP78 and PKM2 expressions are adaptable to the nutritional levels in the microenvironment. Further mechanistic study indicated that GRP78 overexpression activated the Class III PI3K-mediated autophagy pathway and induced autophagic degradation of IKKβ, which caused inactivation of NF-κB pathway and subsequently altered the expression of PKM2 and HIF-1α. Our study establishes GRP78 and PKM2 as the crucial molecular links between cancer cell glucose metabolism and tumor microenvironment alterations.
We investigated whether pretreatment with the neuropeptide cholecystokinin-8 affected methamphetamine (METH)-induced behavioral changes and dopaminergic neurodegeneration in male C57/BL6 mice. CCK-8 pretreatment alone had no effect on locomotion and stereotypic behavior and could not induce behavioral sensitization; however, it attenuated, in a dose-dependent manner, hyperlocomotion and behavioral sensitization induced by a low dose of METH (1mg/kg). CCK-8 attenuated METH-induced stereotypic behavior at a dose of 3mg/kg but not at 10mg/kg. CCK-8 pretreatment attenuated METH (10mg/kg)-induced hyperthermia, the decrease of tyrosine hydroxylase (TH) and dopamine transporter (DAT) in the striatum, and TH in the substantia nigra. CCK-8 alone had no effect on rectal temperature, TH and DAT expression in the nigrostriatal region. In conclusion, our study demonstrated that pretreatment with CCK-8 inhibited changes typically induced by repeated exposure to METH, such as hyperlocomotion, behavioral sensitization, stereotypic behavior, and dopaminergic neurotoxicity. These findings make CCK-8 a potential therapeutic agent for the treatment of multiple symptoms associated with METH abuse.
Peroxisome proliferator-activated receptor γ (PPARγ) and estrogen receptor (ER) belong to a family of nuclear hormone receptors that have been demonstrated to affect each other's transcriptional activity. At present, little is known regarding the effect of PPARγ on ER-mediated transcriptional activity in endometrial carcinoma. In the present study, we aimed to demonstrate the correlation between PPARγ and ER in endometrial carcinoma and to elucidate the biological effects of abnormal expression of PPARγ on endometrial carcinoma cell lines. Immunohistochemical and western blotting methods were used to detect the expression of PPARγ, ERα and ERβ in normal and malignant endometrium. Next, we performed transient transfection to assess the interaction between PPARγ and ER in vitro. Furthermore, we examined cell migration, invasion and proliferation as a biological counterpart. PPARγ and ERα expression levels were significantly associated with pathological grade and clinical stage in endometrial carcinoma (P<0.05). Pearson correlation analysis revealed that PPARγ expression was positively correlated with ERα expression (P<0.05). Using KLE and ERα-positive cells (ECC-1), we demonstrated that the PPARγ regulation of ER expression occurred predominantly through ERα. Moreover, our findings suggest that PPARγ activation inhibited the migration, invasion and proliferation of endometrial carcinoma cells; ECC-1 cells were more sensitive to this inhibition. The present study demonstrated that PPARγ activation inhibited ERα expression in ERα-positive endometrial carcinoma cell lines. This crosstalk may facilitate the development of novel therapeutic methods targeting PPARγ in endometrial carcinoma treatment, particularly ERα-positive carcinomas.
Matrix metalloproteinases (MMPs) have been regarded as major critical molecules assisting tumor cells during metastasis, for excessive ECM (ECM) degradation, and cancer cell invasion. In the present study, in vitro and in vivo assays were employed to examine the inhibitory effects of kaempferol, a natural polyphenol of flavonoid family, on tumor metastasis. Data showed that kaempferol could inhibit adhesion, migration, and invasion of MDA-MB-231 human breast carcinoma cells. Moreover, kaempferol led to the reduced activity and expression of MMP-2 and MMP-9, which were detected by gelatin zymography, real-time PCR, and western blot analysis, respectively. Further elucidation of the mechanism revealed that kaempferol treatment inhibited the activation of transcription factor activator protein-1 (AP-1) and MAPK signaling pathway. Moreover, kaempferol repressed phorbol-12-myristate-13-acetate (PMA)-induced MMP-9 expression and activity through suppressing the translocation of protein kinase Cδ (PKCδ) and MAPK signaling pathway. Our results also indicated that kaempferol could block the lung metastasis of B16F10 murine melanoma cells as well as the expression of MMP-9 in vivo. Taken together, these results demonstrated that kaempferol could inhibit cancer cell invasion through blocking the PKCδ/MAPK/AP-1 cascade and subsequent MMP-9 expression and its activity. Therefore, kaempferol might act as a therapeutic potential candidate for cancer metastasis.
Macrophages are heterogeneous and plastic populations that are an essential component of inflammation and host defense. To understand how macrophages respond to cytokine signals, we used 2DE to identify protein profiles in macrophages stimulated with interleukin 4 (M2) and those stimulated with lipopolysaccharide and interferon γ (M1). In total, 32 differentially expressed proteins in THP-1 cells were identified by MALDI-TOF MS/MS analysis. The different proteins were mainly involved in cellular structure, protein metabolism, stress response, oxidative response, and nitric oxide production during macrophage polarization. In particular, proteins playing important roles in production of nitric oxide (NO) were downregulated in M2 macrophages. Many antioxidant and heat shock proteins, which are related to oxidative response, were upregulated in M2 macrophages. More importantly, a remarkable decrease in intracellular ROS and NO production were detected in M2 macrophages. Our results provide a proteomic profile of differentially polarized macrophages and validate the function of the identified proteins, which may indicate possible mechanism of macrophage polarization process.
The objective of this study was to determine the effects of different transport times on broilers during summer on stress, meat quality, and early postmortem muscle metabolites. Arbor Acres broiler chickens (n = 105) were randomly categorized into 5 treatments: unstressed control, 0.5 h, 1 h, 2 h, and 4 h transport. Each treatment consisted of 3 replicates with 7 birds each. All birds (except the control group) were transported according to a designed protocol. With the extension of transport time, the activities of plasma creatine kinase (CK) and lactate dehydrogenase (LDH) gradually increased. The content of heat shock protein 70 (Hsp70) did not change significantly during 0.5 h transport compared to the control group, but was significantly higher (P < 0.05) at 1 h or more of transport time. Also, transport times of 2 h or more resulted in a death rate of 20%-33% of broilers. We found that the breast meat in the 0.5 h transport group had significantly (P < 0.05) higher L* values, drip loss, cooking loss, AMP/ATP ratio, and phosphorylation of AMP-activated protein kinase (p-AMPK). In addition, pH24h was lower compared to the control group, increasing the likelihood of pale, soft, and exudative (PSE)-like meat. However, no significant variations were found in meat color, drip loss, or cooking loss in other transport groups compared to the control group under the condition of this study. Muscle glycogen content decreased with time of transportation. There were significant correlations among p-AMPK and meat quality (P < 0.05). These results indicate that preslaughter transport during summer may cause severe physiological and biochemical changes of broilers. Further investigations studying the deeper relationship between biological indicators and meat quality according to the similar transport conditions would provide a better understanding of the effect of transport duration on meat quality.
2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (TSG) has been shown to protect human umbilical vein endothelial cells (HUVECs) from lysophosphatidylcholine (LPC)-induced injury; however, the underlying molecular mechanism remains to be determined. The aim of this study was to investigate the protective mechanism of TSG against LPC-induced injury in HUVECs. We established a stable LPC-induced cell model by treating HUVECs with various concentrations of LPC and found 10.0 µg/mL of LPC to be optimal for inducing HUVECs injury. The effects of TSG on LPC-induced cell injury were assessed by cell counting kit-8, apoptosis assay, transmission electron microscope, and measurement of malondialdehyde (MDA), the antioxidant enzymes superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione peroxidase, and mitochondrial membrane potential. The mRNA and protein levels of caspase-3, Bax, Bcl-2, PARP-1, and cytochrome C were assayed by real-time reverse transcriptase-polymerase chain reaction and immunoblotting, respectively. TSG pretreatment was able to prevent LPC-induced HUVECs injury and restore cell viability in a concentration-dependent manner. LPC treated cells showed typical apoptotic morphological changes including cytoplasmic vacuolation, swollen mitochondria, and characteristic biochemical hallmarks of apoptosis including loss of mitochondrial membrane potential, activation of caspase-3, decrease of Bcl-2, increase of PARP-1, upregulation of Bax, and release of cytochrome C, all of which were apparently inhibited by TSG pretreatment. Treatment of HUVECs with LPC led to decrease of SOD and glutathione peroxidase in addition to rapid increase of MDA and ROS levels. Pretreatment with TSG restored SOD and glutathione peroxidase levels to that of normal levels, and significantly decreased ROS and MDA levels. Our data indicate that TSG inhibits apoptosis of HUVECs mediated by LPC through blocking the mitochondrial apoptotic pathway and suggest that the mechanisms underlying the protective effects of TSG are related to the activation of SOD and glutathione peroxidase, the clearance of intracellular ROS, and reduction of lipid peroxidation.
Thyroid cancer is the most common endocrine malignant disease and the incidence is increasing. DACT2 was found frequently methylated in human lung cancer and hepatocellular carcinoma. To explore the epigenetic change and the role of DACT2 in thyroid cancer, 7 thyroid cancer cell lines, 10 cases of non-cancerous thyroid tissue samples and 99 cases of primary thyroid cancer samples were involved in this study. DACT2 was expressed and unmethylated in K1, SW579, FTC-133, TT, W3 and 8505C cell lines. Loss of expression and complete methylation was found in TPC-1 cells. Restoration of DACT2 expression was induced by 5-aza-2'deoxycytidine treatment. It demonstrates that the expression of DACT2 was regulated by promoter region methylation. In human primary papillary thyroid cancer, 64.6% (64/99) was methylated and methylation of DACT2 was related to lymph node metastasis (p<0.01). Re-expression of DACT2 suppresses cell proliferation, invasion and migration in TPC-1 cells. The activity of TCF/LEF was inhibited by DACT2 in wild-type or mutant β-catenin cells. The activity of TCF/LEF was increased by co-transfecting DACT2 and Dvl2 in wild-type or mutant β-catenin cells. Overexpression of wild-type β-catenin promotes cell migration and invasion in DACT2 stably expressed cells. The expression of β-catenin, c-myc, cyclinD1 and MMP-9 were decreased and the level of phosphorylated β-catenin (p-β-catenin) was increased after restoration of DACT2 expression in TPC-1 cells. The expression of β-catenin, c-myc, cyclinD1 and MMP-9 were increased and the level of p-β-catenin was reduced after knockdown of DACT2 in W3 and SW579 cells. These results suggest that DACT2 suppresses human papillary thyroid cancer growth and metastasis by inhibiting Wnt signaling. In conclusion, DACT2 is frequently methylated in papillary thyroid cancer. DACT2 expression was regulated by promoter region methylation. DACT2 suppresses papillary thyroid cancer proliferation and metastasis by inhibiting Wnt signaling.
PIWI-interacting RNAs (piRNAs) are a newly identified class of small non-coding RNAs that can play important roles in germline development and carcinogenesis. In this study, piRNA microarrays were used to investigate global piRNA expression in three bladder cancer tissues and their adjacent normal tissues. Using the 3' untranslated region (UTR) sequence complementarily method, we predicted the target gene of piRNA. Our results showed that the expression levels of 106 piRNAs were up-regulated and 91 were down-regulated in bladder cancer tissues, among which the fold-change of down-regulated piRNA DQ594040 associated with bladder cancer (piRABC) was the highest piRNA. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to confirm piRABC expression in paired bladder cancer tissues and their adjacent normal tissues (n = 25). Over-expression of piRABC can inhibit bladder cancer cell proliferation, colony formation, and promote cell apoptosis (all P < 0.05). Luciferase reporter gene assays indicated that piRABC could increase the luciferase activity of TNFSF4. Western blotting analyses and ELISA assays also confirmed that the expression of TNFSF4 protein was up-regulated in control subjects compared with bladder cancer subjects. In conclusion, piRABC plays a crucial role in the development of bladder cancer.
Bone marrow-derived mesenchymal stem cells (MSCs), which have beneficial effects in acute lung injury (ALI), can serve as a vehicle for gene therapy. Angiotensin-converting enzyme 2 (ACE2), a counterregulatory enzyme of ACE that degrades angiotensin (Ang) II into Ang 1-7, has a protective role against ALI. Because ACE2 expression is severely reduced in the injured lung, a therapy targeted to improve ACE2 expression in lung might attenuate ALI. We hypothesized that MSCs overexpressing ACE2 would have further benefits in lipopolysaccharide (LPS)-induced ALI mice, when compared with MSCs alone. MSCs were transduced with ACE2 gene (MSC-ACE2) by a lentiviral vector and then infused into wild-type (WT) and ACE2 knockout (ACE2(-/y)) mice following an LPS-induced intratracheal lung injury. The results demonstrated that the lung injury of ALI mice was alleviated at 24 and 72 h after MSC-ACE2 transplantation. MSC-ACE2 improved the lung histopathology and had additional anti-inflammatory effects when compared with MSCs alone in both WT and ACE2(-/y) ALI mice. MSC-ACE2 administration also reduced pulmonary vascular permeability, improved endothelial barrier integrity, and normalized lung eNOS expression relative to the MSC group. The beneficial effects of MSC-ACE2 could be attributed to its recruitment into the injured lung and enhanced local expression of ACE2 protein without changing the serum ACE2 levels after MSC-ACE2 transplantation. The biological activity of the increased ACE2 protein decreased the Ang II amount and increased the Ang 1-7 level in the lung when compared with the ALI and MSC-only groups, thereby inhibiting the detrimental effects of accumulating Ang II. Therefore, compared to MSCs alone, the administration of MSCs overexpressing ACE2 resulted in a further improvement in the inflammatory response and pulmonary endothelial function of LPS-induced ALI mice. These additional benefits could be due to the degradation of Ang II that accompanies the targeted overexpression of ACE2 in the lung.
The present study was designed to investigate the potential role of miR-23a-3p in experimental brain ischemia-reperfusion injury. Cerebral ischemia reperfusion was induced by transient middle cerebral artery occlusion (MCAO) for 1h in C57/BL6 mice. And miR-23a-3p angomir was transfected to upregulate the miR-23a-3p level. Our results showed that miR-23a-3p levels were transiently increased at 4h after reperfusion in the peri-infarction area, while markedly increased in the infarction core at reperfusion 4h and 24h. Importantly, in vivo study demonstrated that miR-23a-3p angomir treatment through intracerebroventricular injection markedly decreased cerebral infarction volume after MCAO. Simultaneously, miR-23a-3p reduced peroxidative production nitric oxide (NO) and 3-nitrotyrosine (3-NT), and increased the expression of manganese superoxide dismutase (MnSOD). In vitro study demonstrated that miR-23a-3p decreased hydrogen peroxide (H2O2)-induced lactate dehydrogenase (LDH) leakage dose-dependently, and reduced protein levels of activated caspase-3 in neuro-2a cells. In addition, miR-23a-3p reduced H2O2-induced production of NO and 3-NT dose-dependently, and reversed the decreased activity of total SOD and MnSOD in neuro-2a cells. Our study indicated that miR-23a-3p suppressed oxidative stress and lessened cerebral ischemia-reperfusion injury.
Ceramide synthase 2 (CERS2) is the gene identified from a human liver cDNA library in 2001. Our previous studies have shown higher expression of CERS2 in the breast cancer patients was associated with fewer lymph node metastases. However, the molecular mechanism of CERS2 involved is unknown. Here, we found CERS2 was heterogeneously expressed in various breast cancer cells. The mRNA and protein expression levels of CERS2 in MCF7 cells, which are poorly invasive breast cancer cells, were obviously higher than that in the highly invasive cells MDA-MB-231. Results showed overexpression of CERS2 in MDA-MB-231 cells could significantly inhibit the migration and invasion ability, whereas CERS2 knockdown in MCF7 cells could significantly increase the migration and invasion ability. Overexpression of CERS2 in MDA-MB-231 cells significantly reduced the V-ATPase activity, increased the extracellular pH and decreased the pH-dependent activity of MMP-2 and MMP-9 matrix metalloproteinases (MMPs). CERS2 knockdown in MCF7 cells significantly increased the V-ATPase activity, decreased the extracellular pH and increased the activity of MMP-2 and MMP-9. Taken together, CERS2 can significantly inhibit breast cancer cell invasion and is associated with the decrease of the V-ATPase activity and extracellular hydrogen ion concentration, and in turn the activation of secreted MMP-2/MMP-9 and degradation of extracellular matrix (ECM), which ultimately suppressed tumor's invasion. Thus, CERS2 may represent a novel target for selectively disrupting V-ATPase activity and the invasive potential of cancer cells.
Ammonia is considered to be the main neurotoxin responsible for hepatic encephalopathy resulting from liver failure. Liver failure has been reported to alter expression and activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (Mrp2) at the blood-brain barrier (BBB). The aim of this study was to investigate whether ammonia is involved in abnormalities of expression and activity of P-gp and Mrp2 at the BBB. Hyperammonemic rats were developed by an intraperitoneal injection of ammonium acetate (NH4 Ac, 4.5 mmol/kg). Results showed that Mrp2 function markedly increased in cortex and hippocampus of rats at 6 h following NH4 Ac administration. Significant increase in function of P-gp was observed in hippocampus of rats. Meanwhile, such alterations were in line with the increase in mRNA and protein levels of P-gp and Mrp2. Significant increase in levels of nuclear amount of nuclear factor-κB (NF-κB) p65 was also observed. Primarily cultured rat brain microvessel endothelial cells (rBMECs) were used for in vitro study. Data indicated that 24 h exposure to ammonia significantly increased function and expression of P-gp and Mrp2 in rBMECs, accompanied with activation of NF-κB. Furthermore, such alterations induced by ammonia were reversed by NF-κB inhibitor. In conclusion, this study demonstrates that hyperammonemia increases the function and expression of P-gp and Mrp2 at the BBB via activating NF-κB pathway. Hyperammonemia, a proverbial main factor responsible for neurocognitive disorder and blood-brain barrier (BBB) dysfunction resulting from liver failure, could increase the expression and activity of P-glycoprotein and multidrug resistance-associated protein 2 (Mrp2) at the BBB both in vivo and in vitro. Furthermore, the NF-κB activation stimulated by hyperammonemia may be the potential mechanism underlying such abnormalities induced by hyperammonemia.
NG, O(2)-(2,4-dinitro-5-{[2-(12-en-28-β-D-galactopyranosyl-oleanolate-3-yl)-oxy-2-oxoethyl] amino} phenyl) 1-(N-hydroxyethylmethylamino) diazen-1-ium-1,2-diolate, was identified in our laboratory as a novel nitric oxide-releasing prodrug with antitumor effects. A previous study showed that NG inhibited cell growth, and induced apoptosis in HepG2 cells. In this study, the inhibitory effects of NG on the viability of MGC803 cells were examined using methylthiazolyl tetrazolium biomide (MTT) assay, neutral red assay and trypan blue exclusion test. The results showed that NG had strong cytotoxicity to induce apoptosis, which was characterized by a significant externalization of phosphatidylserine, nuclear morphological changes and enhanced Bax-to-Bcl-2 ratio. Moreover, the release of cytochrome c (Cyt c) from mitochondria and the activation of caspase-9/3 were also detected, indicating that NG may induce apoptosis through a mitochondrial-mediated pathway. NG induced mitochondrial dysfunction in MGC803 cells by altering membrane potential (△Ψm), the inhibition of complexes I, II and IV consequently decreasing ATP level. Furthermore, the treatment of MGC803 cells with NG caused a marked rise in oxidative stress as characterized by accumulation of reactive oxygen species (ROS), excessive malondialdehyde (MDA) production and a reduction in glutathione hormone (GSH) level and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. In addition, pretreatment with N-acetylcysteine (NAC), a GSH synthesis precursor, was partially protective against the NG-induced ROS generation and cell apoptosis. In contrast, pretreatment of MGC803 cells with L-buthionine-S, R-sulfoximine (BSO), a GSH synthesis inhibitor, increased the ROS levels, and aggravated cell apoptosis by NG. These results suggest that NG-induced apoptosis in MGC803 cells is mediated, at least in part, by the increase in ROS production, oxidative stress and mitochondrial dysfunction.
In the previous study, we demonstrated that fluoxetine (FLX) regulated lipogenic and lipolytic genes to promote hepatic lipid accumulation. On this basis, underlying mechanisms were investigated by focusing on the intracellular signaling transduction in the present study using primary mouse hepatocytes. The expression of lipogenesis- and lipolysis-related genes was evaluated with the application of specific activators and inhibitors. Activation status of respective signaling pathway and the lipid accumulation in hepatocytes were analyzed. We provided evidence that AMP-activated protein kinase (AMPK) activator AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) significantly suppressed the increased expression of representative lipogenesis-related genes, acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) by FLX, while increased the repressed expression of lipolysis-related genes, carboxylesterases. In the meanwhile, FLX regulated the above genes in the same way as AMPK inhibitor Compound C did. Furthermore, AICAR inhibited the proteolytic activation of SREBP1c induced by FLX, resulting in the decreased level of nuclear SREBP1c. Further studies demonstrated that FLX significantly suppressed the phosphorylation of AMPK and subsequent phosphorylation of ACC, following the inhibited phosphorylation and nuclear export of liver kinase B1 (LKB1). As a functional analysis, FLX-induced lipid accumulation in hepatocytes was repeatedly abolished by AICAR. In conclusion, FLX-induced hepatic lipid accumulation is mediated by the suppression of AMPK signaling pathway. The findings not only provide new insight into the understanding of the mechanisms for selective serotonin reuptake inhibitors-mediated dyslipidemia effects, but also suggest a novel therapeutic target to interfere.
Gastric cancer is one of the major causes of cancer death worldwide; however, the mechanism of carcinogenesis is complex and poorly understood. Long non-coding RNA HOTAIR (HOX transcript antisense RNA) recently emerged as a promoter of metastasis in various cancers including gastric cancer. Here we investigated the impact of HOTAIR on apoptosis, cell proliferation and cell cycle to dissect the carcinogenesis of gastric cancer. We examined the mechanism of invasion and metastasis and analyzed the clinical significance of HOTAIR. Downregulation of HOTAIR was confirmed by two different siRNAs. The expression of HOTAIR was significantly elevated in various gastric cancer cell lines and tissues compared to normal control. si-HOTAIR significantly reduced viability in MKN 28, MKN 74, and KATO III cells but not in AGS cells. si-HOTAIR induced apoptosis in KATO III cells. Lymphovascular invasion and lymph node metastasis were more common in the high level of HOTAIR group. si-HOTAIR significantly decreased invasiveness and migration. si-HOTAIR led to differential expression of epithelial to mesenchymal transition markers. We found that HOTAIR was involved in inhibition of apoptosis and promoted invasiveness, supporting a role for HOTAIR in carcinogenesis and progression of gastric cancer.
Previous studies have shown that craniofacial bone marrow stromal cells (MSCs) have greater osteogenic potential than appendicular bone MSCs. However, detailed phenotypic characterization of MSCs from bone marrow in the different sites remains unclear. To investigate bone repair and regeneration of craniofacial MSCs and the regulatory mechanisms underlying their unique properties, we compared osteogenesis, cell recruitment, autophagy, and apoptosis resistance of MSCs from the mandible (M-MSCs) to those from tibia (T-MSCs) in vitro and in vivo. Compared with T-MSCs, M-MSCs formed more colonies, possessed stronger proliferation activity, exhibited higher expression of pluripotency genes such as Oct4 and Nanog, and held stronger osteogenic differentiation in osteogenic medium. Moreover, M-MSCs had greater autophagy and anti-apoptotic capacities than T-MSCs under hypoxia and serum deprivation conditions. M-MSCs were found to be more capable of recruiting more MSCs than T-MSCs. When these MSCs were transplanted into mandible critical-sized defects, more bone formed in the M-MSC-treated animals than in their T-MSC counterparts. Collectively, these findings reveal that MSCs have unique characteristics and bone-repairing properties from the mandible as compared with those from tibia, presumably by enhanced osteogenic potential, cell recruitment, autophagy and apoptosis resistance.
Amyloid-β peptide (Aβ), which can invoke a cascade of inflammatory responses, is considered to play a causal role in the development and progress of Alzheimer's disease (AD). Montelukast, known as a cysteinyl leukotriene receptor 1 (CysLT1R) antagonist, is currently used for treatment of inflammatory diseases such as asthma. We have previously reported that CysLT1R activation is involved in Aβ generation. In this study, we investigated rescuing effect of CysLT1R antagonist montelukast on Aβ1-42-induced neurotoxicity in primary neurons. Our data showed that Aβ1-42 elicited a marked increase of CysLT1R expression in primary mouse neurons. This increment of CysLT1R expression was accompanied by increases of inflammatory factors such as NF-κB p65, tumor necrosis factor-α (TNFα) and interleukin-1β (IL-1β) as well as pro-apoptotic protein Caspase-3 activation and anti-apoptosis protein Bcl-2 reduction. Aβ1-42-mediated increase of CysLT1R expression was associated with Aβ1-42-induced cytotoxicity as measured by MTT reduction assay and lactate dehydrogenase (LDH) release assay. This observation was confirmed with treatment of montelukast, a selective CysLT1R antagonist, which had significant effect on Aβ1-42-induced cytotoxicity. Moreover, blockade of CysLT1R with montelukast reversed Aβ1-42-mediated increase of CysLT1R expression, and concomitant changes of the pro-inflammatory factors and the apoptosis-related proteins. The results demonstrate that montelukast rescued neurons against Aβ1-42-induced neurotoxicity, neuroinflammation and apoptosis by down-regulating CysLT1R-mediated NF-κB signaling, suggesting that CysLT1R may be a potential target for AD, and its antagonist may have beneficial effects for treatment of AD.
Maternal malnutrition may disrupt ovarian functions in adult offspring. Steroidogenesis and folliculogenesis in the offspring ovary appear to be the major targets of nutritional programming. Nevertheless, the mechanism by which maternal low-protein diet affects the offspring steroidogenesis and folliculogenesis, and the possible pathway linking these two processes remain unclear. In this study, Landrace×Yorkshire crossbred sows were fed either standard (SP) or low-protein (LP, 50% of the SP) diets throughout gestation and lactation. Female offspring were fed the same diet after weaning until 6 months of age. LP offspring had higher serum 17β-estradiol level (P<0.01), which was accompanied by lower mRNA (P<0.05) but higher protein (P<0.05) expression of cytochrome P450 aromatase (CYP19A1) in the ovary. CYP19A1 protein up-regulation was associated with lower ovarian expression of drosha (P<0.05) and miRNAs targeting CYP19A1 (P<0.05). LP offspring had less graafian follicles with more apoptotic granulosa cells (P<0.05), as well as higher caspase 3 activity (P<0.05) and FasL expression (P<0.05) in the ovary. FasL gene up-regulation was associated with higher ERα protein expression (P<0.05) and binding to FasL gene promoter. These results suggest that a maternal LP diet in pregnancy and lactation elevated serum 17β-estradiol level by activating CYP19A1 through miRNA-mediated mechanism, and induced granulosa apoptosis in graafian follicles through ER-activated Fas/FasL-caspase 3 pathway.
Hepatic fibrosis is concomitant with sinusoidal pathological angiogenesis, which has been highlighted as novel therapeutic targets for the treatment of chronic liver disease. Our prior studies have demonstrated that curcumin has potent antifibrotic activity, but the mechanisms remain to be elucidated. The current work demonstrated that curcumin ameliorated fibrotic injury and sinusoidal angiogenesis in rat liver with fibrosis caused by carbon tetrachloride. Curcumin reduced the expression of a number of angiogenic markers in fibrotic liver. Experiments in vitro showed that the viability and vascularization of rat liver sinusoidal endothelial cells and rat aortic ring angiogenesis were not impaired by curcumin. These results indicated that hepatic stellate cells (HSCs) that are characterized as liver-specific pericytes could be potential target cells for curcumin. Further investigations showed that curcumin inhibited VEGF expression in HSCs associated with disrupting platelet-derived growth factor-β receptor (PDGF-βR)/ERK and mTOR pathways. HSC motility and vascularization were also suppressed by curcumin associated with blocking PDGF-βR/focal adhesion kinase/RhoA cascade. Gain- or loss-of-function analyses revealed that activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) was required for curcumin to inhibit angiogenic properties of HSCs. We concluded that curcumin attenuated sinusoidal angiogenesis in liver fibrosis possibly by targeting HSCs via a PPAR-γ activation-dependent mechanism. PPAR-γ could be a target molecule for reducing pathological angiogenesis during liver fibrosis.
Proteasome inhibition can induce abnormal accumulation and phosphorylation of microtubule-associated protein tau. The major function of tau protein is to promote microtubules assembly and stabilization, and abnormal tau protein would disturb its microtubule-binding function. In this study, proteasome inhibitor MG132 was used to treat hippocampal slices to explore the role and mechanism of Akt/glycogen synthase kinase-3β (GSK-3β) in proteasome inhibition-induced tau abnormality. During the culture period, we measure the lactate dehydrogenase (LDH) content to assay the viability of hippocampal slices. Following 2.5 and 5 μM MG132 treatment for 6 h, we detected the expression, phosphorylation modification, and microtubule-binding function of tau protein of slices. We also analyzed the changed activities of glycogen synthase kinase-3β (GSK-3β) and protein kinase B (PKB/Akt) and the level of heat shock protein 90 (Hsp90) in the process. In addition, co-immunoprecipitation was used to investigate the interaction between Akt and Hsp90, Akt and protein phosphatase-2A (PP2A) in the MG132-treated organotypic hippocampal slices. Our results indicated that proteasome inhibition led to degradation obstacles and abnormal phosphorylation of tau protein. The downregulated Akt/GSK-3β signaling pathway might be responsible for the abnormal phosphorylation of tau protein at multiple sites which further reduced the microtubule-binding function of tau protein. Furthermore, proteasome inhibition decreased the binding capacity of Akt-Hsp90 while increased the Akt-PP2A binding ability which mediated Akt inactivity. This current study establishes a hippocampal slice model targeting Akt/GSK-3β signaling pathway to explore the pivotal role of proteasome inhibition in tau pathology.
We aimed to investigate how 5-FU-PLA-O-CMC-NP (5-FPOCN) inhibits the proliferation of the SW480 colon cancer cell line. Following the treatment of cell line SW480 with 0.1, 1, 10 or 100 μg/ml 5-FPOCN or 5-fluorouracil (fluorouracil, 5-Fu) for 0, 24, 48, or 72, the rate of cell was tested by the tetrazolium assay (MTT). After the SW480 cells were treated with 5-FPOCN or 5-FU for 72 h, the growth rate and apoptosis were detected. After the SW480 cells were treated with 5-FPOCN or 5-FU for 24, 48, 72, or 120, flow cytometry (FCM) was used to determine the cell cycle distribution. The changes in the expression of P21, CyclinD1 and Rb were detected by Western blotting and real-time PCR. We found that different doses of 5-FPOCN can significantly inhibit the growth rate of SW480 cells, and this effect is dose and time dependent. However, there is no significant difference from 72 to 120 h (P>0.05). After 5-FPOCN treatment for 72 h, there is a negative correlation between the concentration of 5-FPOCN and the activity of SW480 cells and a positive correlation between the concentration of 5-FPOCN and SW480 cell apoptosis. G1 phase was significantly increased, and S phase was significantly decreased in 5-FPOCN-treated SW480 cells at 72 h compared to the control group (P<0.05); there was a positive correlation between the concentration of 5-FPOCN and the above changes. It was suggested that 5-FPOCN can delay G1/S phase and that this is a dose-dependent effect. The expression of P21 protein and messenger RNA (mRNA) and Rb protein and mRNA was significantly increased in 5-FPOCN-treated SW480 cells at 72 h compared to the control group, and this was a dose- and time-dependent effect. CyclinD1 protein and mRNA expression was reduced as the dose increased, and its expression was negatively associated with the increased expression of P21. We concluded that 5-FPOCN can significantly inhibit the growth of colon cancer SW480 cells. 5-FPOCN increased P21 expression and decreased cyclin family and pRb expression to promote cell cycle delay and apoptosis.
While cancer cell mitochondria mediate actions of many successful chemotherapeutics, little is known about mitochondrial response in mTOR-targeted anticancer therapy. We have studied mitochondrial dynamics in relation to growth suppression employing an allosteric inhibitor rapalog, a highly selective mTOR kinase inhibitor (mTOR-KI) and mTOR-ShRNA. Global targeting of mTOR increased mitochondrial membrane potential (mΔψ) and inhibited mitochondrial permeability transition pore (mPTP). Importantly, these mTOR-KI-provoked anti-survival and pro-survival effects were differentially manifested in diverse cancer cells according to intrinsic susceptibility to mTOR-targeting. The most-sensitive cells including those possessing hyperactive PI3K/AKT/mTOR and/or growth factor-dependence (LNCap, MDA361 and MG63) all displayed a dramatic increase in mΔψ, whereas the mΔψ increase was not evident in majority of resistant cancer cells. Upon mTOR-KI treatment, the resistant cells including those harboring K-Ras- or B-Raf mutation (MDA231, HT29 and HCT116) all displayed a markedly reduced mPTP opening, which paralleled a sustained AKT-hexokinase 2 (HK2) survival signaling and persistent phosphorylation (inactivation) of GSK3β. Further studies demonstrated that the mTOR-KI-provoked mPTP closure in resistant cells was mediated through an enhanced binding of HK2 to the mitochondrial voltage-dependent anion channel (VDAC), a molecular mechanism known to promote mPTP closure and cell survival. Detaching HK2 from VDAC by an HK2-displacing peptide or methyl jasmonate specifically blocked the mTOR-KI-provoked mPTP closure and potentiated growth suppression in resistant cells. Thus, mTOR-inhibition can exert complex and differential perturbation to mitochondrial dynamics in cancer cells, which likely influence therapeutic outcome of mTOR-targeted therapy.
Essential oils of Cymbopogon citratus were already reported to have wide ranging medical and industrial applications. However, information on polysaccharides from the plant and their anticancer activities are limited. In the present study, polysaccharides from C. citratus were extracted and fractionated by anion exchange and gel filtration chromatography. Two different polysaccharide fractions such as F1 and F2 were obtained, and these fractions were found to have distinct acidic polysaccharides as characterized by their molecular weight and sugar content. NMR spectral analysis revealed the presence of (1→4) linked b-d-Xylofuranose moiety in these polysaccharides. Using these polysaccharide fractions F1 and F2, anti-inflammatory and anticancer activities were evaluated against cancer cells in vitro and the mechanism of action of the polysaccharides in inducing apoptosis in cancer cells via intrinsic pathway was also proposed. Two different reproductive cancer cells such as Siha and LNCap were employed for in vitro studies on cytotoxicity, induction of apoptosis and apoptotic DNA fragmentation, changes in mitochondrial membrane potential, and profiles of gene and protein expression in response to treatment of cells by the polysaccharide fractions. These polysaccharide fractions exhibited potential cytotoxic and apoptotic effects on carcinoma cells, and they induced apoptosis in these cells through the events of up-regulation of caspase 3, down-regulation of bcl-2 family genes followed by cytochrome c release.
Marine macroalgae consist of a range of bioactive molecules exhibiting different biological activities, and many of these properties are attributed to sulfated polysaccharides, fucoxanthin, phycobiliproteins, and halogenated compounds. In this study, a glycoprotein (GLP) with a molecular mass of ∼48 kDa was extracted and purified from Codium decorticatum and investigated for its cytotoxic properties against human MDA-MB-231 breast cancer cells. The IC₅₀ values of GLP against MDA-MB-231 and normal breast HBL-100 cells (control) were 75 ± 0.23 μg/mL (IC₂₅), 55 ± 0.32 μg/mL (IC₅₀), and 30 ± 0.43 μg/mL (IC₇₅) and 90 ± 0.57 μg/mL (IC₂₅), 80 ± 0.48 μg/mL (IC₅₀), and 60 ± 0.26 μg/mL (IC₇₅), respectively. Chromatin condensation and poly(ADP-ribose) polymerase (PARP) cleavage studies showed that the GLP inhibited cell viability by inducing apoptosis in MDA-MB-231 cells. Induction of mitochondria-mediated intrinsic apoptotic pathway by GLP was evidenced by the events of loss of mitochondrial membrane potential (ΔΨ(m)), bax/bcl-2 dysregulation, cytochrome c release, and activation of caspases 3 and 9. Apoptosis-associated factors such as reactive oxygen species (ROS) formation and loss of ΔΨ(m) were evaluated by DCFH-DA staining and flow cytometry, respectively. Cell cycle arrest of G₂/M phase and expression of apoptosis associated proteins were determined using flow cytometry and Western blotting, respectively.
Beta-amyloid (Aβ)-mediated inflammation plays a critical role in the initiation and progression of Alzheimer׳s disease (AD). Anti-inflammatory treatment may provide therapeutic benefits. In this study, the effect of hydroxy-safflor yellow A (HSYA) on Aβ1-42-induced inflammation in AD mice was investigated and the underlying mechanisms were explored. Aβ1-42 was injected into bilateral hippocampi of mice to induce AD models in vivo. Spatial learning and memory of mice were investigated by the Morris water maze test. Activated microglia and astrocytes were examined by immunofluorescence staining for ionized calcium-binding adapter molecule-1 (Iba-1) and glial fibrillary acidic protein (GFAP). The mRNA of inflammatory cytokines were measured using real-time PCR. NF-κB p65 translocation was analyzed by western blotting and immunostaining. IκB and phosphorylation of JAK2 and STAT3 were tested by western blotting. The results showed that HSYA ameliorated the memory deficits in Aβ1-42-induced AD mice. HSYA suppressed Aβ1-42-induced activation of microglia and astrocytes and reduced the mRNA expression of pro-inflammatory mediators. HSYA up-regulated the JAK2/STAT3 pathway and inhibits the activation of NF-κB signaling pathways. Pharmacological inhibition of STAT3 by AG490 reversed the inactivation of p65 and anti-inflammatory effects of HSYA. In conclusion, these results suggest that HSYA protects Aβ1-42-induced AD model through inhibiting inflammatory response, which may involve the JAK2/STAT3/NF-κB pathway.
Tumor necrosis factor (TNF)-α is a potent cytokine that regulates critical cellular processes including apoptosis. TNF-α usually triggers both survival and apoptotic signals in various cell types. Heat shock protein 27 (HSP27), an important cellular chaperone, is believed to protect cells from apoptosis. HSP27 can be phosphorylated and changed its cellular function according to different stimuli. However, available reports on the role of HSP27 phosphorylation in apoptosis remain elusive. In this study, we investigated the role of HSP27 phosphorylation in TNF-α induced apoptosis in human cervical carcinoma (HeLa) cells. We found that TNF-α induced apoptosis was enhanced if we suppressed the TNF-α induced HSP27 phosphorylation by specific inhibitor CMPD1 or MAPKAPK2 (MK2) knockdown or by overexpression of non-phosphorylatable mutant HSP27-3A. Through co-immunoprecipitation and confocal microscopy, we observed that HSP27 associated with transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) in response to TNF-α stimulation. By blocking MK2 activity or overexpressing phospho-mimetic mutant Hsp27-3D, we further showed that HSP27 phosphorylation facilitated the TNF-α induced ubiquitination and phosphorylation of TAK1 and the activations of p38 MAPK and ERK, the TAK1 downstream pro-survival signaling. In addition, we also found that increased HSP27 phosphorylation inhibited TRADD ubiquitination but did not influence the binding between TRADD and FADD in a pro-apoptotic complex. Taken together, our data indicated that HSP27 phosphorylation was involved in modulating the TNF-α induced apoptosis via interacting with TAK1 and regulating TAK1 post-translational modifications in HeLa cells. This study demonstrates that HSP27 phosphorylation serves as a novel regulator in TNF-α-induced apoptosis, and provides a new insight into the cytoprotective role of HSP27 phosphorylation.
Cancer cells, compared with normal cells, are under increased oxidative stress with higher level of reactive oxygen species (ROS). When exposed to environmental stresses such as ROS, NFE-related factor 2 (Nrf2) is the key to antioxidant response by transcriptionally activating various detoxification and antioxidant enzymes. Previously, we have shown that wogonin, a flavonoid isolated from the root of Scutellaria baicalensis Georgi, could reverse drug resistance in MCF-7/DOX cells by blocking the translocation of Nrf2 into nucleus. However, the exact mechanism underlying the effect remains unclear. In this study, we observed that wogonin reduced the Nrf2 nuclear translocation, and therefore elevated the level of intracellular ROS to accomplish the purpose of killing malignant cells. Furthermore, the suppression of Nrf2 by wogonin can potentiate cytotoxic effects of chemotherapeutic agents in HepG2 cells. On one hand, down-regulation of Nrf2 lead to reduction of cytoprotective effect by inducing phage II enzymes which sensitize cells to chemotherapeutic agents. On the other hand, inhibition of multidrug resistance-associated proteins (MRPs) by wogonin enhances the effective drug level in cancer cells and potentiates their chemotherapeutic effects. Finally, we found that the decrease of Nrf2 may be related to overexpression of p53. Using p53 siRNA to knock down the endogenous p53 expression, the levels of both c-myc and Nrf2 in nucleus increased when exposed to wogonin. The present study indicates that wogonin can be used in chemotherapy not only because of its own antitumor ability, but also due to the enhanced cytotoxic effects of chemotherapeutic agents.
Granulocyte/macrophage colony-stimulating factor (GM-CSF) can accelerate wound healing by promoting angiogenesis. The biological effects of GM-CSF in angiogenesis and the corresponding underlying molecular mechanisms, including in the early stages of primitive endothelial tubule formation and the later stages of new vessel maturation, have only been partially clarified. This study aimed to investigate the effects of GM-CSF on angiogenesis and its regulatory mechanisms. Employing a self-controlled model (Sprague-Dawley rats with deep partial-thickness burn wounds), we determined that GM-CSF can increase VEGF expression and decrease the expression ratio of Ang-1/Ang-2 and the phosphorylation of Tie-2 in the early stages of the wound healing process, which promotes the degradation of the basement membrane and the proliferation of endothelial cells. At later stages of wound healing, GM-CSF can increase the expression ratio of Ang-1/Ang-2 and the phosphorylation of Tie-2 and maintain a high VEGF expression level. Consequently, pericyte coverages were higher, and the basement membrane became more integrated in new blood vessels, which enhanced the barrier function of blood vessels. In summary, we report here that increased angiogenesis is associated with GM-CSF treatment, and we indicate that VEGF and the Ang/Tie system may act as angiogenic mediators of the healing effect of GM-CSF on burn wounds.
The inflammasome is a multi-protein complex which when activated regulates caspase-1 activation and IL-1β secretion. Inflammasome activation is mediated by NLR proteins that respond to stimuli. Among NLRs, NLRP3 senses the widest array of stimuli. NLRP3 inflammasome plays an important role in the development of many cancer types. However, Whether NLRP3 inflammasome plays an important role in the process of hepatocellular carcinoma (HCC) is still unknown. Here, the anticancer effect of luteoloside, a naturally occurring flavonoid isolated from the medicinal plant Gentiana macrophylla, against HCC cells and the underlying mechanisms were investigated. Luteoloside significantly inhibited the proliferation of HCC cells in vitro and in vivo. Live-cell imaging and transwell assays showed that the migration and invasive capacities of HCC cells, which were treated with luteoloside, were significantly inhibited compared with the control cells. The inhibitory effect of luteoloside on metastasis was also observed in vivo in male BALB/c-nu/nu mouse lung metastasis model. Further studies showed that luteoloside could significantly reduce the intracellular reactive oxygen species (ROS) accumulation. The decreased levels of ROS induced by luteoloside was accompanied by decrease in expression of NLRP3 inflammasome resulting in decrease in proteolytic cleavage of caspase-1. Inactivation of caspase-1 by luteoloside resulted in inhibition of IL-1β. Thus, luteoloside exerts its inhibitory effect on proliferation, invasion and metastasis of HCC cells through inhibition of NLRP3 inflammasome. Our results indicate that luteoloside can be a potential therapeutic agent not only as an adjuvant therapy for HCC, but also, in the control and prevention of metastatic HCC.
Successful embryonic implantation requires an effective maternal-embryonic molecular dialogue. However, the detailed mechanisms of epithelial-embryo adhesion remain poorly understood. Here, we report that matrix metalloproteinase-26 (MMP-26) is a novel downstream target gene of homeobox a 10 (HOXA10) in human endometrial cells. HOXA10 binds directly to a conserved TTAT unit (-442 to -439) located within the 5' regulatory region of the MMP-26 gene and regulates the expression and secretion of MMP-26 in a concentration-dependent manner. Moreover, the adenovirus-mediated overexpression of MMP-26 in Ishikawa cells markedly increased BeWo spheroid adhesion. An antibody blocking assay further demonstrated that the promotion of BeWo spheroid adhesion by HOXA10 and MMP-26 was significantly inhibited by pre-treatment with a specific antibody against MMP-26. These results demonstrate that the HOXA10-mediated expression of MMP-26 promotes embryo adhesion during the process of embryonic implantation.
Prion diseases are neurodegenerative disorders characterized by the accumulation of a disease-associated prion protein and apoptotic neuronal death. Previous studies indicated that the ubiquitous expression of c-Abl tyrosine kinase transduces a variety of extrinsic and intrinsic cellular signals. In this study, we demonstrated that a synthetic neurotoxic prion fragment (PrP106-126) activated c-Abl tyrosine kinase, which in turn triggered the upregulation of MST1 and BIM, suggesting the activation of the c-Abl-BIM signaling pathway. The peptide fragment was found to result in cell death via mitochondrial dysfunction in neuron cultures. Knockdown of c-Abl using small interfering RNA protected neuronal cells from PrP106-126-induced mitochondrial dysfunction, production of reactive oxygen species, and apoptotic events inducing translocation of Bax to the mitochondria, cytochrome c release into the cytosol, and activation of caspase-9 and caspase-3. Blocking the c-Abl tyrosine kinase also prevented neuronal cells from PrP106-126-induced apoptotic morphological changes. This is the first study reporting that c-Abl tyrosine kinase as a novel upstream activator of MST1 and BIM plays an important role in prion-induced neuron apoptosis via mitochondrial dysfunction. Our findings suggest that c-Abl tyrosine kinase is a potential therapeutic target for prion disease.
Glucocorticoid receptor (GR) is transcribed in a tissue- and cell-specific manner with multiple exon 1 mRNA variants driven by selective promoters. We recently cloned and characterized the 5.3kb proximal promoter sequence of porcine GR gene containing 7 untranslated alternative first exons each processed by a distinct promoter. In this study, we showed tissue-specific expression of total GR and its exon 1 mRNA variants in hippocampus, muscle and liver of pigs. Total GR mRNA was most abundant in liver, followed by muscle and hippocampus in descending order. Among all the GR exon 1 mRNA variants detected, GR exon 1-9/10 and 1-4 were the most predominant variants in all the three tissues. The abundance of GR exon 1-4 mRNA was similar to that of 1-10 in muscle, but was significantly lower than 1-10 in liver and hippocampus. The activities of truncated short (S) and long (L) promoters of respective GR exon 1 mRNA variants were analyzed by luciferase reporter assay in 3 representative cell lines, SY5Y, C2C12 and HepG2. S1-10 and S1-4 demonstrated significantly higher activities than other short promoters in all the cell lines examined. Nevertheless, the strongest activity and cell specificity were detected for L1-10 promoter, which was consistent with the predominant exon 1-9/10 expression in porcine tissues. Moreover, with 3 potential nGRE binding sites, L1-10 promoter was more sensitive to dexamethasone (DEX) in HepG2. Our data provide basic knowledge of the transcriptional mechanism underlying the tissue- and cell-specific expression of porcine GR under basal or ligand-stimulated conditions.
The nuclear factor of activated T cell (NFAT) family of calcium-regulated transcription factors plays a key role in the development and function of the immune system. Calcineurin, a protein phosphatase, activates NFAT by dephosphorylation. The activated NFAT is translocated into the nucleus, where it up-regulates the expression of interleukin 2 (IL-2) and other target genes. Calcineurin inhibitors such as cyclosporine A (CsA) and FK506 are effective immunosuppressant drugs and dramatically increase the success rate of organ transplantation procedures. However, since calcineurin is expressed in most tissues in the body and calcineurin inhibition alters many cellular processes besides immune cell activation, the therapeutic use of calcineurin inhibitors is limited by serious side effects. Thus inhibiting NFAT by other mechanisms such as blocking its binding to DNA could be a more selective and safer approach to target NFAT for therapeutic applications. In peripheral T cells, productive immune responses are dependent upon the cooperative binding of the NFAT/AP-1 transcriptional complex to the promoter regions of genes such as interleukin-2 (IL-2), while NFAT in the absence of AP-1 leads to T cell anergy. Protein transduction domains (PTDs) are able to penetrate cell membranes and can be used to transport exogenous proteins across the cell and nuclear membranes. In this study, we constructed a fusion protein of PTD and a minimum DNA binding domain of human NFAT1 (PTD-ΔNFATminiDBD), which contains two mutations (R466A and T533G) in the AP-1 binding sites. The delivery and functions of this fusion protein in T cells were investigated. The results indicated that PTD-ΔNFATminiDBD could be effectively delivered into T cells and transported into the nucleus. PTD-ΔNFATminiDBD attenuated IL-2 production in T cells and then inhibited T cell proliferation, likely through competing against endogenous NFAT for binding to the IL-2 gene promoter. These results demonstrated that PTD-ΔNFATminiDBD was an effective NFAT inhibitor with a novel mechanism of action and might potentially be used as an immunosuppressant for organ transplantation with higher safety and better tolerance than calcineurin inhibitors.
D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced lethality and acute liver failure is dependent on endogenously produced inflammatory cytokines. Adenosine has been proven to be a central role in the regulation of inflammatory response. It is not entirely clear that which adenosine action is actually crucial to limiting inflammatory tissue destruction. Here we showed that GalN/LPS challenge elevated hepatic adenosine and induced lethality in adenosine receptor-deficient mice with equal efficiency as wild-type mice. In GalN/LPS-treated mice, pretreatment with adenosine 5'-monophosphate (5'-AMP) significantly elevated hepatic adenosine level and reduced mortality through decreasing cytokine and chemokine production. In RAW264.7 cells, 5'-AMP treatment inhibited the production of inflammatory cytokines, which is not mediated through adenosine receptors. 5'-AMP failed to attenuate LPS-induced nuclear factor-κB (NF-κB) p65 nuclear translocation, but reduced LPS-induced recruitment of NF-κB p65 to inflammatory gene promoters and decreased LPS-induced enrichment of H3K4 dimethylation at the tumor necrosis factor-α (TNF-α) promoter, which was involved in 5'-AMP-induced elevation of cellular adenosine and a decline of methylation potential. In vitro biochemical analysis revealed that adenosine directly attenuated recruitment of NF-κB to the TNF-α and interleukin-6 promoters. Our findings demonstrate that 5'-AMP-inhibiting inflammatory response is not mediated by adenosine receptors and it may represent a potential protective agent for amelioration of LPS-induced liver injury.
B cell activating factor (BAFF) and its receptors were regarded as elements of the immune system, regulating the fate of B cell. In recent years, these molecules were identified in a number of normal and pathological tissues, expanding their potential functions beyond the immune system. In this study, on the basis of molecular clone and prokaryotic expression of equine BAFF, we reported that equine adipose-derived stem cell (ASC) expressed BAFF and its receptors, which exhibited the increased expression during ASC adipogenic differentiation in vitro. Moreover, with the addition of recombinant protein His6-sBAFF, an increased differentiation of equine ASC towards adipocyte was detected. These results suggested that BAFF and its receptors might be associated with the differentiation process of ASC towards adipocyte in horse.
The precise mechanism through which the two estrogen receptor subtypes, ERα and ERβ, are linked to endometrial malignant progression is not fully understood. The aim of the present study was to examine their role in endometrial carcinoma cell migration, invasion and proliferation. We also explored the correlation between the ERs and phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathways in endometrial carcinoma cells. Using Ishikawa and KLE cells as model systems, we performed transient transfection to upregulate ERα and ERβ expression; fluorescence microscopy analysis was then employed to evaluate transfection efficiencies, RT-PCR and western blot assays were used to evaluate the mRNA and protein levels. We further examined the effects on cell migration, invasion and proliferation. We showed that ERα raised the phosphorylation levels of PI3K p85α, activated the phosphorylation of AKT and mTOR in Ishikawa and KLE cells, but ERβ had no effect on PI3K p85α phosphorylation. Moreover, the overexpression of ERs enhanced cell migration, invasion and proliferation. The effect on the activation of the PI3K/AKT/mTOR transduction cascade by ERα explains, at least in part, the enhancement on cell invasion and proliferation exerted by overexpression of ERα. This crosstalk could be taken into account in developing novel therapeutic methods by targeting the ERα and PI3K/AKT/mTOR pathways in endometrial carcinoma.
Cathepsin S (CatS) is a cysteine protease normally present in lysosomes. It has long been regarded as an enzyme that is primarily involved in general protein degradation. More recently, mounting evidence has shown that it is involved in Alzheimer disease, seizures, age-related inflammatory processes, and neuropathic pain. In this study, we investigated the time course of CatS protein and mRNA expression and the cellular distribution of CatS in a mouse model of traumatic brain injury (TBI). To clarify the roles of CatS in TBI, we injected the mice intraventricularly with LHVS, a nonbrain penetrant, irreversible CatS inhibitor, and examined the effect on inflammation and neurobehavioral function. We found that expression of CatS was increased as early as 1 h after TBI at both protein and mRNA levels. The increased expression was detected in microglia and neurons. Inhibition of CatS significantly reduced the level of TBI-induced inflammatory factors in brain tissue and alleviated brain edema. Additionally, administration of LHVS led to a decrease in neuronal degeneration and improved neurobehavioral function. These results imply that CatS is involved in the secondary injury after TBI and provide a new perspective for preventing secondary injury after TBI.
Accumulation of amyloid-β (Aβ) is thought to be associated with the progressive neuronal death observed in Alzheimer's disease, but the mechanisms underlying neurotoxicity triggered by Aβ remain elusive. In the current study, we investigated the roles of cysteinyl leukotriene receptor 1 (CysLT1R) in Aβ1-42-induced neurotoxicity in vitro or in vivo. In vitro exposure of mouse primary neurons to Aβ1-42 caused a gradual increases in CysLT1R expression. In vivo bilateral intrahippocampal injection of Aβ1-42 also elicited time-dependent increases of CysLT1R expression in the hippocampus and cortex of mice. The CysLT1R antagonist pranlukast not only reversed Aβ1-42-induced upregulation of CysLT1R, but also suppressed Aβ1-42-triggered neurotoxicity evidenced by enhanced nuclear factor-kappa B p65, activated caspase-3, decreased B-cell lymphoma-2 and cell viability and impaired memory. Furthermore, chronic treatment with pranlukast produced similar beneficial effects on memory behavior and hippocampal long-term potentiation to memantine or donepezil in intrahippocampal Aβ1-42-injected mice. Our data indicate that CysLT1R is involved in Aβ1-42-induced neurotoxicity, and that blockade of CysLT1R, such as application of CysLT1R antagonist, could be a novel and promising strategy for the treatment of Alzheimer's disease.
Extracellular polysaccharides (EPSs) are high-molecular weight sugar-based polymers that are synthesized and secreted by many microorganisms. Recently, EPSs have attracted particular attention due to their multiple biological functions including anti-inflammation. However, studies rarely reported the molecular mechanisms underlying their functions. We previously purified an EPS from an oligotrophic bacteria (Bacillus sp. LBP32) found in Lop Nur Desert, which possesses a potent antioxidant activity, while the anti-inflammatory effects of EPS and signaling mechanisms underlying its action have not been clarified. In this study, we demonstrated that EPS significantly inhibited the LPS-induced release of pro-inflammatory mediators, such as nitric oxide (NO), IL-6 and TNF-α, without any significant cytotoxicity. EPS also downregulated the expression of nitric oxide synthase (iNOS) induced by LPS. Furthermore, activation of nuclear factor κB (NF-κB) was abrogated by EPS through inhibited the phosphorylation of IκB kinase (IKK). Activations of Mitogen-activated protein kinases (MAPKs), including p38 MAPK and c-Jun N-terminal kinase (JNK), were also found to be inhibited by EPS. In addition, the level of intracellular reactive oxygen species (ROS) was also significantly decreased with the treatment of EPS. In vivo experiments were conducted and showed that EPS could greatly improve the outcome of mice with LPS-induced endotoxic shock. Taken together, our data indicate that EPS prevents LPS-induced inflammatory response by inhibiting NF-κB and MAPKs activation and ROS production.
In the present study, we used chronic gavage administration of alcohol with gradual increases in alcohol concentration and volume to generate a rat model of chronic alcohol intoxication. We measured the changes in biological, behavioral, pathological and vascular injury-related molecular biological markers, and explored the effects of nimodipine intervention on alcohol intoxication. We found that chronic alcohol consumption induced a variety of behavioral abnormalities, accompanied by severe pathological changes in cerebral arterioles, prefrontal cortex and cerebellar tissue, as well as an upregulation of vascular endothelial growth factor (VEGF), leptin receptor (ob-R) and endothelin-1 (ET-1). Treatment with mimodipine for 15 days significantly improved behavioral abnormalities, alleviated the pathological changes in blood vessels and brain tissues, increased VEGF expression, decreased ob-R expression, reduced plasma ET-1 leakage and protected vascular and neuronal functions.
Activation of hepatic stellate cells (HSCs) is a pivotal event leading to extracellular matrix (ECM) overproduction during hepatic fibrogenesis. Compelling evidence indicates that cannabinoid receptors (CBRs) play an important role in chronic liver disease. Antagonism of hepatic CBR type 1 (CBR1) could be a novel therapeutic strategy for liver fibrosis. Our previous studies have demonstrated that curcumin has potent antifibrotic activity, but the mechanisms remain to be elucidated. The current work was to examine the curcumin effect on CBRs system and its relevance to inhibition of ECM expression in HSCs. Our in vivo data demonstrated that curcumin ameliorated fibrotic injury, and downregulated CBR1 but upregulated CBR2 at both mRNA and protein levels in rat fibrotic liver caused by carbon tetrachloride. The subsequent in vitro investigations showed that curcumin reduced the mRNA and protein abundance of CBR1 in cultured HSCs and decreased the expression of three critical ECM proteins. Further analyses revealed that CBR1 agonist abrogated the curcumin inhibition of ECM expression, but CBR1 antagonist mimicked and reinforced the curcumin effects. Autodock simulations predicted that curcumin could bind to CBR1 with two hydrogen bonds. Collectively, our current studies revealed that curcumin reduction of liver fibrosis was associated with modulation of CBRs system and that antagonism of CBR1 contributed to curcumin inhibition of ECM expression in HSCs.
Nrf2-mediated activation of ARE regulates expression of cytoprotective enzymes against oxidative stress, inflammation, and carcinogenesis. We have discovered a novel structure (1) as an ARE inducer via luciferase reporter assay to screen the in-house database of our laboratory. The potency of 1 was evaluated by the expression of NQO-1, HO-1, and nuclear translocation of Nrf2 in HCT116 cells. In vivo potency of 1 was studied using AOM-DSS models, showing that the development of colorectal adenomas was significantly inhibited. Administration with 1 lowered the expression of IL-6, IL-1β, and promoted Nrf2 nuclear translocation. These results indicated that 1 is a potent Nrf2/ARE activator, both in vitro and in vivo. Forty-one derivatives were synthesized for SAR study, and a more potent compound 17 was identified. To our knowledge, this is a potent ARE activator. Besides, its novel structure makes it promising for further optimization.
3-Oxo-29-noroleana-1,9(11),12-trien-2,20-dicarbonitrile (ONTD) is a novel synthetic derivative of glycyrrhetinic acid (GA), which has the ability to inhibit the proliferation of human hepatocellular carcinoma (HCC) cells. However, the mechanisms by which ONTD exerts its inhibitory effects remain elusive. The present study was conducted to investigate the cytotoxicity of ONTD in Bel-7402 cells and its molecular mechanisms. We found that ONTD depleted intracellular GSH, increased the level of ROS, and consequently induced mitochondrial permeability transition (MPT) leading to the release of apoptosis-inducing factor (AIF) and cytochrome c (Cyt c) to the cytosol. Mitochondrial alteration and subsequent apoptotic cell death in ONTD-treated Bel-7402 cells could be blocked by addition of exogenous antioxidants N-acetylcystein (NAC), GSH and the MTP inhibitor cyclosporin A (CsA). In addition, ONTD activated the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPK) but not extracellular signal-regulated protein kinases (ERK 1/2). When the cells were exposed to SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor), the deregulation of the expression of apoptotic proteins was attenuated. Furthermore, 40 mg/kg ONTD significantly reduced tumor weight (-70.62%, p<0.01) in the H22 tumor-bearing mouse model in vivo. Taken together, these findings provide the first experimental evidence supporting that ONTD could induce apoptosis of Bel-7402 cells via MAPK-mediated mitochondrial pathway and ONTD has the potential to be developed as a therapeutic agent for the treatment of HCC.
Advanced glycation endproducts (AGEs) and its precursor methylglyoxal are associated with diabetic nephropathy (DN). Mangiferin has many beneficial biological activities, including anti-inflammatory, anti-oxidative and anti-diabetic effects. We investigated the effect of mangiferin on DN and its potential mechanism associated with glyoxalase 1 (Glo-1), a detoxifying enzyme of methylglyoxal, in streptozotocin-induced rat model of DN. Diabetic rats were treated orally with mangiferin (15, 30, and 60 mg/kg) or distilled water for 9 weeks. Kidney tissues were collected for morphologic observation and the determination of associated biochemical parameters. The cultured mesangial cells were used to measure the activity of Glo-1 in vitro. Chronic treatment with mangiferin significantly ameliorated renal dysfunction in diabetic rats, as evidenced by decreases in albuminuria, blood urea nitrogen, kidney weight index, periodic acid-schiff stain positive mesangial matrix area, glomerular extracellular matrix expansion and accumulation, and glomerular basement membrane thickness. Meanwhile, mangiferin treatment caused substantial increases in the enzymatic activity of Glo-1 in vivo and in vitro, and protein and mRNA expression of Glo-1, reduced levels of AGEs and the protein and mRNA expression of their receptor (RAGE) in the renal cortex of diabetic rats. Moreover, mangiferin significantly attenuated oxidative stress damage as reflected by the lowered malondialdehyde and the increased glutathione levels in the kidney of diabetic rats. However, mangiferin did not affect the blood glucose and body weight of diabetic rats. Therefore, mangiferin can remarkably ameliorate DN in rats through inhibiting the AGEs/RAGE aix and oxidative stress damage, and Glo-1 may be a target for mangiferin action.
Toll-like receptors (TLRs) and glucocorticoid receptor (GR) act respectively as effectors of innate immune and stress responses. The crosstalk between them is critical for the maintenance of homeostasis during the immune response. Vaccination is known to boost adaptive immunity, yet it remains elusive whether vaccination may affect GR/TLR interactions following infection. Duroc×Meishan crossbred piglets were allocated to three groups. The control group (CC) received neither vaccination nor infection; the non-vaccinated infection group (NI) was artificially infected intratracheally with Mycoplasma hyopneumoniae (M. hyopneumoniae); while the vaccinated, infected group (VI) was vaccinated intramuscularly with inactivated M. hyopneumoniae one month before infection. The clinical signs and macroscopic lung lesions were significantly reduced by vaccination. However, vaccination did not affect the concentration of M. hyopneumoniae DNA in the lung. Serum cortisol was significantly decreased in both NI and VI pigs (P<0.01), but only VI pigs demonstrated significantly diminished nuclear GR content. TLRs 1-10 were all expressed in lung, among which TLR2 was the most abundant and was significantly up-regulated (P<0.05) in NI pigs, but not in VI pigs. Accordingly, GR binding to the GR response element on TLR2 promoter was significantly increased (P<0.05) in NI pigs, but not in VI pigs. These results suggest that the inhibition of GR nuclear translocation and binding to the TLR2 promoter, which results in diminished TLR2 expression, is associated with the protective effect of vaccination on M. hyopneumoniae-induced lung lesions in the pig.
It has been previously reported that follicle-stimulating hormone (FSH) regulates the expression of inhibin-alpha in human granulosa cells, but the precise molecular pathway remains unknown. In the present study, we investigated the role of the orphan nuclear receptor, NUR77, in both the transcriptional regulation of the inhibin α-subunit gene and the secretion of inhibins. Our results showed that in a human granulosa cell tumor-derived cell line (KGN) and in human granulosa-lutein cells (hGL), FSH induced the expression of NUR77 and inhibin-alpha, although inhibin-alpha expression did not increased following FSH treatment if NUR77 was knocked down. Furthermore, simply overexpressing or reducing NUR77 levels affected inhibin-alpha expression, while NUR77 overexpression improved the secretion of inhibin A and B from human granulosa cells. In addition, chromatin immunoprecipitation-PCR, avidin-biotin-conjugated DNA precipitation, and luciferase reporter assays confirmed that NUR77 directly regulated the transcription of the inhibin-alpha gene through the specific NGFI-B response element located within its promoter. In the ovarian granulosa cells of the Nur77 knockout mice, the mRNA levels of inhibin-alpha were decreased relative to wild-type mice. These data indicate a role of NUR77 in the regulation of inhibin-alpha in ovarian granulosa cells.
The enzyme 3β-hydroxysteroid dehydrogenase/Δ(5)-Δ(4)-isomerase (3β-HSD) catalyzes the biosynthesis of all steroid hormones. The molecular mechanisms regulating porcine adrenal 3β-HSD expression in different breeds are still poorly understood. In this study, we aimed to compare the expression of 3β-HSD between preweaning purebred Large White (LW) and Erhualian (EHL) piglets and to explore the potential factors regulating 3β-HSD transcription. EHL had significantly higher serum levels of cortisol (P<0.01) and testosterone (P<0.01), which were associated with significantly higher expression of 3β-HSD mRNA (P<0.01) and protein (P<0.05) in the adrenal gland, compared with LW piglets. The 5' flanking region of the porcine 3β-HSD gene showed significant sequence variations between breeds, and the sequence of EHL demonstrated an elevated promoter activity (P<0.05) in luciferase reporter gene assay. Higher adrenal expression of 3β-HSD in EHL was accompanied with higher CCAAT/enhancer binding protein β (C/EBPβ) expression (P<0.05), enriched histone H3 acetylation (P<0.05) and C/EBPβ binding to 3β-HSD promoter (P<0.05). In addition, higher androgen receptor (AR) (P=0.06) and lower glucocorticoid receptor (GR) (P<0.05) were detected in EHL. Co-immunoprecipitation analysis revealed interactions of C/EBPβ with both AR and GR. These results indicate that the C/EBPβ binding to 3β-HSD promoter is responsible, at least in part, for the breed-dependent 3β-HSD expression in adrenal gland of piglets. The sequence variations of 3β-HSD promoter and the interactions of AR and/or GR with C/EBPβ may also participate in the regulation.
Forkhead L2 (Foxl2) is expressed in ovarian granulosa cells and participates in steroidogenesis by transcriptionally regulating target genes such as steroidogenic acute regulatory protein (StAR) and CYP19A1. In this study, a direct link between microRNA-133b (miR-133b) and Foxl2-mediated estradiol release in granulosa cells was established. miR-133b was involved in follicle-stimulating hormone (FSH)-induced estrogen production. Luciferase assays confirmed that miR-133b was bound to the 3' untranslated region (3'UTR) of Foxl2 mRNA. Consistent with this finding, miR-133b overexpression reduced the Foxl2 levels. Furthermore, miR-133b inhibited Foxl2 binding to the StAR and CYP19A1 promoter sequences. These results demonstrate that miR-133b down-regulates Foxl2 expression in granulosa cells by directly targeting the 3'UTR, thus inhibiting the Foxl2-mediated transcriptional repression of StAR and CYP19A1to promote estradiol production.
Chemotherapy resistance represents a major problem for the treatment of patients with lung carcinomas. Parthenolide (PN), a naturally occurring small molecule found in herb feverfew, has been used in clinical treatment. Although its importance in treating the chemotherapy resistance has been shown, the pharmacological benefits of PN for lung cancer with multidrug resistance are underappreciated. Using human lung epithelial carcinoma A549 and A549 derived DOX-resistant A549/DOX cell lines, we found that PN enhanced the apoptotic cytotoxicity of DOX in A549/DOX cells. PN inhibited P-glycoprotein (P-gp) up-regulation and promoted the intracellular accumulation of DOX in A549/DOX cells. PN also exhibited inhibitory effect on NF-κB activation in A549/DOX cells, suggesting that inhibition of NF-κB was involved in attenuating P-gp expression by PN. Moreover, we found that PN could also effectively inhibit the HSP70 up-regulation in A549/DOX cells. Further studies revealed a positive correlation between HSP70 and P-gp expression. Overexpression of HSP70 upregulated P-gp expression independently of NF-κB activation in A549 cells, and knockdown of HSP70 caused a reduced expression of P-gp in A549/DOX cells. RT-PCR experiments showed that HSP70 modulated the P-gp expression mainly at transcription level. Taken together, PN can reverse DOX resistance through suppressing P-gp expression by mechanisms involving attenuation of NF-κB activation and HSP70 up-regulation. Our results not only provide insight into potential use of PN in reversing P-gp mediated MDR to facilitate lung cancer chemotherapy, but also highlight a potential role of HSP70 in the development of drug resistance.
Concomitant administration of herbal medicines with drugs that are P-glycoprotein (P-gp) substrates may produce significant herb-drug interactions. The purpose of this study was to evaluate the effects of Schisandra lignans extract (SLE) on P-gp thoroughly in vitro and in vivo, and to investigate the possible P-gp-based herb-drug interactions. In the in vitro experiments, the effect of SLE on the uptake and transport for P-gp substrates in Caco-2, LLC-PK1 and L-MDR1 cells were carefully investigated. Verapamil, a known P-gp inhibitor, was used as a positive control drug. Results shown that, 10 μM verapamil and SLE (0.5, 2.0, and 10.0 μg/ml) were observed to significantly enhance the uptake and inhibit the efflux ratio of P-gp substrates in Caco-2 and L-MDR1 cells. In vivo experiments showed that single-dose SLE at 500 mg/kg could increase the area under the plasma concentration time curve of digoxin and vincrisine significantly without affecting terminal elimination half-time. Long-term treatment with SLE for continuous 10 days could also increase the absorption of P-gp substrates with greatly down regulation of P-gp expression in rat intestinal and brain tissues. In conclusion, SLE was a strong P-gp inhibitor, which indicated a potential herb-drug interaction when SLE was co-administered with P-gp substrate drugs.
β-Casomorphin-7 (β-CM-7) is regarded as the most representative milk-derived bioactive peptide. The present work studies the efficacy of β-CM-7 against myocardial injury in streptozotocin-induced diabetic rats, focusing on the following assays: (1) the level of blood glucose and advanced glycosylation end product (AGE), the activity of lactate dehydrogenase (LDH) in serum; (2) the level of hydrogen peroxide (H2O2), the activity of Na(+)K(+)-ATPase, Ca(2+)Mg(2+)-ATPase and enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) in myocardial tissue; (3) the protein expression of glucose transporter-4 (GLUT-4) in myocardial tissue. It showed that with the influence of β-CM-7, the levels of blood glucose of β-CM-7 treatment group decreased markedly compared with model group (P<0.01) accompanied with their alleviated symptoms of diabetes. In the antioxidant and oxidant levels, β-CM-7 treatment group signified a remarkable increase in the activity of GSH-Px, SOD and CAT of the anti-oxidation system and meanwhile demonstrated a considerable reduction in H2O2 content (all P<0.05) in comparison with model group. We also found both the content of AGE and the activity of LDH of β-CM-7 treated group considerably reduced while the content of GLUT-4 and the activity of Na(+)K(+)-ATPase and Ca(2+)Mg(2+)-ATPase of β-CM-7 treated group increased obviously (P<0.05). Meanwhile the cardiac indexes were significantly lessened. Thus our assay validates that the remedy employing β-CM-7 may treat diabetic cardiomyopathy with high efficacy predominantly associated with the mechanism that β-CM-7 ameliorates myocardial energy metabolism and abates free-radical-mediated oxidative stress in blood and myocardium.
Oxidative stress results in protein oxidation and is implicated in cerebral disease, such as Parkinson's disease, Alzheimer's disease, and ischemic stroke. Sulfiredoxin-1 (Srxn1) is an endogenous antioxidant protein that has neuroprotective effects. The mechanisms of Srxn1 in oxidative stress have not been well studied, however. This study used 180 μM H2 O2 exposure for 24 hr to model oxidative stress. This experimental design allowed us to explore the protective effects and underlying mechanisms of Srxn1 in PC12 cells. To investigate Srxn1's role in oxidative stress protection, transient knockdowns of Srxn1 in PC12 cells were performed prior to treatment with 180 μM H2 O2 for 24 hr. Knockdown of Srxn1 resulted in decreased cell viability and increased cellular damage as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and lactate dehyrogenase analysis, respectively. Intracellular superoxide dismutase and glutathione are important indexes of oxidative stress; these were reduced in Srxn1 knockdown PC12. We further found that the decreased Srxn1 correlated with a reduction in 2-Cys Prdxs activity. Moreover, 2-Cys Prdxs protein levels were increased in the H2 O2 -dosed cells, as measured by RT-PCR and immunoblot analysis. These results suggested that Srxn1 can protect PC12 cells from H2 O2 -induced oxidative stress and are involve in Prdxs activity. Srxn1 play a protective role against oxidative injury and demonstrates potential as a target for neuroprotective intervention in oxidative stress.
Various factors can affect the functions of dental pulp stem cells (DPSCs). However, little knowledge is available about the effects of estrogen deficiency on the differentiation of DPSCs. In this study, an estrogen-deficient rat model was constructed and multi-colony-derived DPSCs were obtained from the incisors of ovariectomized (OVX) or sham-operated rats. Odonto/osteogenic differentiation and the possible involvement of the nuclear factor kappa B (NF-κB) pathway in the OVX-DPSCs/Sham-DPSCs of these rats were then investigated. OVX-DPSCs presented decreased odonto/osteogenic capacity and an activated NF-κB pathway, as compared with Sham-DPSCs. When the cellular NF-κB pathway was specifically inhibited by BMS345541, the odonto/osteogenic potential in OVX-DPSCs was significantly upregulated. Thus, estrogen deficiency down-regulated the odonto/osteogenic differentiation of DPSCs by activating NF-κB signaling and inhibition of the NF-κB pathway effectively rescued the decreased differentiation potential of DPSCs.
Therapeutic strategies designed to inhibit the activation of microglia may lead to significant advancement in the treatment of most neurodegenerative diseases. Dalesconols B, also termed as TL2, is a newly found polyketide from a mantis-associated fungus and has been reported to exert potent immunosuppressive effects. In the present study, the anti-inflammatory effects of TL2 was investigated in lipopolysaccharide (LPS)-treated BV2 microglia and primary microglia cells. Our observations indicated that pretreatment with TL2 significantly inhibited the production of NO and PGE2 and suppressed the expression of pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS), COX-2, TNF-α, IL-1β, IL-6, MCP-1 and MIP-1α in LPS-stimulated BV2 microglia. The nuclear translocation of NF-κB and the phosphorylation level of Akt, p38 and JNK MAP kinase pathways were also inhibited by TL2 in LPS-treated BV2 microglia. Moreover, TL2 also decreased Aβ-induced production of TNF-α, IL-1β and IL-6 in BV2 microglia. Additionally, TL2 protected primary cortical neurons against microglia-mediated neurotoxicity. Overall, our findings suggested that TL2 might be a promising therapeutic agent for alleviating the progress of neurodegenerative diseases associated with microglia activation.
Members of the KLFs family of transcription factors play roles in maternal endometrium development during embryo implantation. However, the specific role of KLF12 in endometrium development has not yet been described. In this study, we showed that KLF12 expression in human endometrial stromal cells (HESCs) was significantly decreased after decidualization stimulated by 8-Br-cAMP and medroxyprogesterone acetate (MPA). The adenovirus-mediated overexpression of KLF12 in HESCs significantly repressed the expression and secretion of decidualization biomarker genes and their products decidual prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP-1) induced by 8-Br-cAMP and MPA. Moreover, CHIP and luciferase reporter assays demonstrated that KLF12 bound to a CAGTGGG element within the decidual prolactin promoter and decreased decidual PRL promoter (dPRL/-2000Luc) activation in a sequence-specific manner. Taken together, these findings suggest KLF12 is a negative regulator of human endometrial stromal cell decidualization.
Inhibition of poly(ADP-ribose) polymerase (PARP) has been proposed to have a neuroprotective effect on hippocampal neurons in animal models of epilepsy. However, the mechanisms of PARP-mediated epileptic neuron apoptosis in vitro are still not thoroughly understood. Therefore, we investigated the effect of PARP inhibition and the underlying mechanisms in the hippocampal neuronal culture model of acquired epilepsy which is generally accepted as the neuronal culture model of spontaneous seizure discharge in vitro. As a result, PARP was activated and the administration of 3,4-dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)-isoquinolinone (DPQ), an inhibitor of PARP, significantly decreased the percentage of neuron apoptosis induced by Mg(2+)-free treatment. Western blot and confocal laser scanning microscopy (CLSM) analysis showed that DPQ increased the phosphorylation of Akt and attenuated mitochondria-nucleus translocation of the apoptosis-inducing factor (AIF). Furthermore, wortmannin, an inhibitor of PI-3K, inhibited the translocation of AIF to the nucleus. The results of the present study demonstrated that the inhibition of PARP might have therapeutic value in seizure-induced hippocampal neuron damage in vitro via suppressing Akt-mediated AIF translocation.
Chlorogenic acid (CGA) is a type of polyphenol with anti-inflammatory, antioxidant activities. Our previous studies showed CGA could efficiently inhibit carbon tetrachloride (CCl(4))-induced liver fibrosis in rats. However, the specific underlying mechanism remains unclear. The aim of this study is to investigate the effects of CGA on liver inflammation and fibrosis induced by CCl(4) and whether they are related to inhibition of toll-like receptor 4 (TLR4) signaling pathway. Male Sprague-Dawley (SD) rats were administrated CCl(4) together with or without CGA for 8 weeks. Histopathological and biochemical analyses were carried out. The mRNA and protein expression levels of proinflammatory and profibrotic mediators were detected by RT-PCR and Western blot, respectively. The levels of serum proinflammatory cytokines were detected by ELISA. CGA significantly attenuated CCl(4)-induced liver damage and symptoms of liver fibrosis, accompanied by reduced serum transaminase levels, collagen I and α-smooth muscle actin (α-SMA) expression. As compared with the CCl(4)-treated group, the expression levels of TLR4, myeloid differentiation factor 88 (MyD88), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were reduced in the treatment group of CCl(4) and CGA, whereas bone morphogenetic protein and activin membrane-bound inhibitor (Bambi) expression was increased. CGA also suppressed CCl(4) induced nuclear factor-κB (NF-κB) activation. Moreover, the hepatic mRNA expression and serum levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were significantly increased in CCl(4)-treated rats and attenuated by co-treatment with CGA. Our data indicate that CGA can efficiently inhibit CCl(4)-induced liver fibrosis in rats and the protective effect may be due to the inhibition of TLR4/MyD88/NF-κB signaling pathway.
The aim of this study was to determine the therapeutic efficiency of bog bilberry anthocyanin extract (BBAE) treatment starting 1 d after spinal cord injury (SCI) in rats and to investigate the underlying mechanism. The BBAE contained cyanidin-3-glucoside, malvidin-3-galactoside and malvidin-3-glucoside. SCI models were induced using the weight-drop method in Sprague-Dawley rats and additionally with sham group (laminectomy only). The animals were divided into four groups: vehicle-treated group; 10 mg/kg BBAE-treated group; 20 mg/kg BBAE-treated group; sham group. BBAE-treated or vehicle-treated group was administered orally at one day after SCI and then daily for 8 weeks. Locomotor functional recovery was assessed during the 8 weeks post operation period by performing a Basso, Beattie, and Bresnahan (BBB) locomotor score test. At the end of study, the animals were killed, and 1.5 cm segments of spinal cord encompassing the injury site were removed for immunohistochemistry, histopathological and western blotting analysis. Immunohistochemistry for GFAP, aggrecan, neurocan and NeuN was used to assess the degree of astrocytic glial scar formation and neuron survival. Immunohistochemistry and western blotting analysis for TNF-α, IL-6, IL-1β was used to evaluate the anti-inflammation effect of BBAE. To evaluate its inhibition effect on the astrocytes, we performed the MTT assay and immunohistochemistry for Ki67 in vitro. Results show that the BBAE-treated animals showed significantly better locomotor functional recovery, neuron death and smaller glial scar formation after spinal cord injury in vivo. In addition, BBAE administration could inhibit astrocyte proliferation in vivo and vitro. Therefore, BBAE may be useful as a promising therapeutic agent for SCI.
Improving the early detection rate and surveillance of bladder cancer remains a great challenge in medicine. Here, we identified sixteen proteins including Gc-globulin (GC) in urine from bladder cancer patients and normal controls by two-dimensional fluorescent differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Bioinformatics analyses indicated GC played important roles in the regulation of growth, apoptosis, death and epidermal growth factor receptor activity. The GC expression patterns in urine or tissue from cases and controls were further quantified by western blotting, immunohistochemical staining and enzyme-linked immunosorbent assay (ELISA). ELISA quantification by correcting for creatinine expression showed GC-Cr was significantly increased in bladder cancer patients than in benign bladder damages cases and normal controls (1013.70±851.25 versus 99.34±55.87, 105.32±47.81 ng/mg, respectively). Receiver operating characteristic (ROC) analysis suggested that at 161.086 ng/mg urinary GC, bladder cancer could be detected with 92.31% sensitivity and 83.02% specificity, and 1407.481 ng/mg with 82.61% sensitivity and 88.24% specificity could be used for the detection of infiltrating urothelial carcinoma of bladder cancer. Taken together, we identified GC as a potential novel urinary biomarker for the early detection and surveillance of bladder cancer.
O(2)-(2,4-dinitro-5-{[2-(12-en-28-β-D- galactopyranosyl-oleanolate-3-yl) -oxy-2-oxoethyl]amino}phenyl)1-(N-hydroxyethylmethylamino)diazen-1-ium-1,2- diolate (NG), a novel PABA/NO-based derivative of oleanolic acid (OA), has been found to show potent antitumor activity both in vivo and in vitro. In the present study, NG could significantly reduce tumor volume and weight in the H22 solid tumor mouse model. Meanwhile, NG showed selective effects on the HepG2 cells including NO generation, cytotoxic effect and apoptosis, which were prevented by hemoglobin (NO scavenger). Moreover, NG-induced apoptosis of HepG2 cells was characteristic of intracellular reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential (Δψm) and enhanced Bax-to-Bcl-2 ratio. The release of apoptotic inducing factor (AIF) and cytochrome c (Cyt c) from mitochondria and the activation of caspase-3, 9 were also detected, indicating that NG may induce apoptosis through a mitochondrial-mediated pathway. Simultaneously, NG treatment could lead to the activation of the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAPK but not ERK1/2. Treatment with SP600125 (an inhibitor of JNK) and SB203580 (an inhibitor of p38) prior to NG was found to reverse NG-induced apoptosis. Moreover, it was found that antioxidant N-acetylcysteine (NAC) blocked the induction of apoptosis and partly reversed the activation of JNK and p38, up-regulation of Bax, down-regulation of Bcl-2 and the activation of caspase-3 in NG-treated cells. Taking together, these findings suggest that NO can be released from NG, which induces apoptosis through a ROS/MAPK-mediated mitochondrial pathway.
Baohuoside I (also known as Icariside II) is a flavonoid isolated from Epimedium koreanum Nakai. Although Baohuoside I exhibits anti-inflammatory and anti-cancer activities, its molecular targets/pathways in human lung cancer cells are poorly understood. Therefore, in the present study, we investigated the usefulness of Baohuoside I as a potential apoptosis-inducing cytotoxic agent using human adenocarcinoma alveolar basal epithelial A549 cells as in vitro model. The apoptosis induced by Baohuoside I in A549 cells was confirmed by annexin V/propidium iodide double staining, cell cycle analysis and dUTP nick end labeling. Further research revealed that Baohuoside I accelerated apoptosis through the mitochondrial apoptotic pathway, involving the increment of BAX/Bcl-2 ratio, dissipation of mitochondrial membrane potential, transposition of cytochrome c, caspase 3 and caspase 9 activation, degradation of poly (ADP-ribose) polymerase and the over-production of reactive oxygen species (ROS). A pan-caspase inhibitor, Z-VAD-FMK, only partially prevented apoptosis induced by Baohuoside I, while NAC, a scavenger of ROS, diminished its effect more potently. In addition, the apoptotic effect of Baohuoside I was dependent on the activation of ROS downstream effectors, JNK and p38(MAPK), which could be almost abrogated by using inhibitors SB203580 (an inhibitor of p38(MAPK)) and SP600125 (an inhibitor of JNK). These findings suggested that Baohuoside I might exert its cytotoxic effect via the ROS/MAPK pathway.
NK cells are important innate immune cells with potent cytotoxicity that can be activated by type I IFN from the host once infected. How NK cell cytotoxicity is activated by type I IFN and then tightly regulated remain to be fully elucidated. MicroRNAs (miRNAs, or miRs) are important regulators of innate immune response, but the full scale of miRNome in human NK cells remains to be determined. In this study, we reported an in-depth analysis of miRNomes in resting and IFN-α-activated human NK cells, found two abundant miRNAs, miR-378 and miR-30e, markedly decreased in activated NK cells by IFN-α, and further proved that miR-378 and miR-30e directly targeted granzyme B and perforin, respectively. Thus, IFN-α activation suppresses miR-378 and miR-30e expression to release cytolytic molecule mRNAs for their protein translation and then augments NK cell cytotoxicity. Importantly, the phenomena are also confirmed in human NK cells activated by other cytokines and even in the sorted CD16(+)CD56(dim)CD69(+) human NK cell subset. Finally, miR-378 and miR-30e were proved to be suppressors of human NK cell cytotoxicity. Taken together, our results reveal that downregulated miR-378 and miR-30e during NK cell activation are negative regulators of human NK cell cytotoxicity, providing a mechanistic explanation for regulation of NK cell function by miRNAs.
Western blot analysis is a commonly used technique for determining specific protein levels in clinical samples. For normalization of protein levels in Western blot, a suitable loading control is required. On account of its relatively high and constant expression, β-actin has been widely employed in Western blot of cell cultures and tissue extracts. However, β-actin's presence in human plasma and this protein's putative role as a plasma-based loading control for Western blot analysis remain unknown. In this study, an enzyme-linked immunosorbent assay was used to determine the concentration of β-actin in human plasma, which is 6.29±0.54 ng/ml. In addition, the linearity of β-actin immunostaining and loaded protein amount was evaluated by Western blot, and a fine linearity (R²=0.974±0.012) was observed. Furthermore, the expression of plasma β-actin in major depressive disorder subjects and healthy controls was compared. The data revealed no statistically significant difference between these two groups. Moreover, the total coefficient of variation for β-actin expression in the two groups was 9.2±1.2%. These findings demonstrate that β-actin is present in human plasma and may possibly be used as a suitable loading control for plasma-based Western blot analysis in major depressive disorder.
The infection of host cells by porcine circovirus type 2 (PCV2) leads to extensive modulation of the gene expression levels of target cells. To uncover the pathogenesis and virus-host interactions of PCV2, a quantitative proteomic study using the stable isotope labeling with amino acids in cell culture (SILAC), coupled with mass spectrometry, was performed on PCV2-infected PK-15 cells. The SILAC-based approach identified 1341 proteins, 163 of which showed significant change in level at 72 h after infection (79 up-regulated and 84 down-regulated). The modulated proteins included a number of proteins involved in substrate transport, cytoskeletal changes, and the stress response. Changes in the expression levels of selected proteins were verified by Western blot analysis. Ingenuity Pathway Analysis was used to reveal protein and interactive pathway regulation in response to PCV2 infection. Functional network and pathway analyses could provide insights into the complexity and dynamics of virus-host cell interactions and may accelerate our understanding of the mechanisms of PCV2 infection.
Pharmacological compounds that release nitric oxide (NO) have been recognized as the potential therapeutic agents for acute stroke. (S)-ZJM-289 is a novel NO-releasing derivative of 3-n-butylphthalide (NBP) with enhanced anti-platelet and anti-thrombotic actions. The present study was performed to investigate the neuroprotective effects and related mechanisms of (S)-ZJM-289 on ischemic neuronal injury in vitro and in vivo. Primary cortical neuronal cultures were exposured to oxygen-glucose deprivation followed by recovery (OGD/R), a model of ischemia-like injury, and treated with (S)-ZJM-289 before OGD. In vitro results showed that (S)-ZJM-289 attenuated OGD/R-induced neuronal injury, which was associated with the maintenance of mitochondrial integrity and function by alleviating intracellular calcium overload and reactive oxygen species (ROS) accumulation, preventing mitochondrial membrane depolarization and preserving respiratory chain complexes activities. Moreover, (S)-ZJM-289 treatment suppressed mitochondrial release of cytochrome c (cyt c) and nuclear translocation of apoptosis-inducing factor (AIF), thereby blocking mitochondria-mediated cell death, which may be partially mediated by up-regulation of Hsp70. The neuroprotection by (S)-ZJM-289 was also studied using a model of middle cerebral artery occlusion (MCAO). Oral administration of (S)-ZJM-289 at the onset of reperfusion for 3d significantly reduced the brain infarct size, improved neurological deficit and prevented neuronal loss and apoptosis. In current study, (S)-ZJM-289 appears to be more potent in ischemic neuroprotection than NBP, in particular at the lower doses, which may be due to the synergistic action of NBP and NO. These findings point to that (S)-ZJM-289 could be an attractive alternative to NBP in preventing the process of ischemia/reperfusion (I/R) injury.
Previously, we employed a proteomics-based 2-D gel electrophoresis assay to show that exposure to 10μM benzo(a)pyrene (BaP) during a 24 h frame can lead to changes in nuclear protein expression and alternative splicing. To further expand our knowledge about the DNA damage response (DDR) induced by BaP, we investigated the nuclear protein expression profiles in HeLa cells treated with different concentrations of BaP (0.1, 1, and 10μM) using this proteomics-based 2-D gel electrophoresis assay. We found 125 differentially expressed proteins in BaP-treated cells compared to control cells. Among them, 79 (63.2%) were down-regulated, 46 (36.8%) were up-regulated; 8 showed changes in the 1μM and 10μM BaP-treated groups, 2 in the 0.1μM and 10μM BaP-treated groups, 4 in the 0.1μM and 1μM BaP-treated groups, and only one showed changes in all three groups. Fifty protein spots were chosen for liquid chromatography-tandem mass spectrometry (LC-MS/MS) identification, and of these, 39 were identified, including subunits of the 26S proteasome and Annexin A1. The functions of some identified proteins were further examined and the results showed that they might be involved in BaP-induced DDR. Taken together, these data indicate that proteomics is a valuable approach in the study of environmental chemical-host interactions, and the identified proteins could provide new leads for better understanding BaP-induced mutagenesis and carcinogenesis.
Growing evidence indicates that the alteration of microRNA (miRNA) expression in tumors that is induced by chemical carcinogens plays an important role in tumor development and progression. However, the mechanism underlying miRNA involvement in lung carcinogenesis induced by anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide (anti-BPDE) remains unclear. In our study, we used the malignant transformation of human bronchial epithelial cells (16HBE-T) induced by anti-BPDE to explore the mechanisms of human lung carcinogenesis. We found that expression of miR-506 was reduced in 16HBE-T transformed malignant human bronchial epithelial cells compared with 16HBE normal human bronchial epithelial cells. Restoration of miR-506 in 16HBE-T cells led to a decrease in cell proliferation, G0/G1 phase cell cycle arrest, as well as significantly suppressed anchorage-dependent growth in vitro and tumor growth inhibition in a nude mouse xenograft model. In addition, we provided novel evidence regarding the role miR-506 potentially plays in negatively regulating the protein and mRNA expression level of N-Ras in cancer cells. Together, these findings revealed that miR-506 acts as an anti-oncogenic miRNA (anti-oncomir) in malignantly transformed cells. The identification of tumor suppressive miRNAs could provide new insight into the molecular mechanisms of chemical carcinogenesis.
Three forms of nano-trititanate (H(2)Ti(3)O(7) nanomaterial) were prepared by a hydrothermal method to replace nano-TiO(2) for sterilizing the environment. The bactericidal capabilities of these nano-trititanates were observed to be more significant compared to nano-TiO(2) both with and without exposure to UV light. For the future commercial applications of those nano-trititanates, we investigated their cytotoxicity and genotoxicity to HEp-2 cells. As data in our study shows, nanoplate, one of the nano-trititanates, possesses the lowest toxicity to HEp-2 cells. The results indicated that the shape and length of the material only affect the toxicity of nano-trititanate but not its bactericidal effect. Thus, through manipulating the shape or length of nano-trititanate, we may obtain a more powerful bactericidal reagent with lower toxicity to the human body.
BACKGROUND:
Subarachnoid hemorrhage (SAH) is a devastating neurological injury with high morbidity and mortality that is mainly caused by early brain injury (EBI). Progranulin (PGRN) is known to be involved in various biological functions, such as anti-inflammation and tissue repair. This study aimed to investigate the change of PGRN in the brain after SAH and its role on EBI.
METHODS:
The levels of PGRN, myeloperoxidase (MPO), interleukin1β (IL-1β), and tumor necrosis factor-α (TNF-α) were detected in the cerebrospinal fluid (CSF) from SAH patients by enzyme-linked immunosorbent assay (ELISA). In addition, PGRN levels were also detected in the cerebral cortex after experimental SAH in rats by western blotting and immunohistochemistry (IHC). Recombinant human PGRN (r-PGRN) or an equal volume of phosphate-buffered saline (PBS) was administrated at 30 min after SAH. All rats were subsequently sacrificed at 24 h after SAH. Neurological score and brain water content were assessed. For mechanistic studies, the changes of MPO, matrix metalloproteinase-9 (MMP-9), zonula occludens 1 (ZO-1), Bcl-2, and cleaved caspase-3 were examined by western blotting and the levels of pro-inflammatory cytokines (IL-1β and TNF-α) were determined by ELISA. In addition, neuronal apoptosis and blood brain barrier (BBB) permeability were examined.
RESULTS:
The levels of PGRN significantly decreased, and the levels of MPO, IL-1β, and TNF-α were markedly elevated in the CSF from SAH patients. In rats, PGRN levels in the brain also decreased after SAH. Administration of r-PGRN decreased brain water content and improved neurological scores at 24 h after SAH. These changes were associated with marked reductions in MPO, MMP-9, and proinflammation cytokine levels, as well as increased levels of Bcl-2 and ZO-1. In addition, neuronal apoptosis and BBB permeability were alleviated by r-PGRN.
CONCLUSIONS:
These results indicate that the levels of PGRN decreased after SAH and that r-PGRN alleviates EBI after SAH possibly via inhibition of neutrophil recruitment, providing a new target for the treatment of SAH.
BACKGROUND:
Subarachnoid hemorrhage (SAH) is one of the life-threatening diseases with high morbidity and mortality rates. SUMO-specific proteases 3 (SENP3), a member of the small ubiquitin-like modifier specific protease family, was identified as an isopeptidase that deconjugates SUMOylation (The covalent modification by SUMO) of modified protein substrates. It is reported that SUMO-2/3 conjugation, a member of SUMOylation, presented neuroprotection. The study aimed to evaluate the expression of SENP3 and to explore its potential role in SAH.
MATERIALS AND METHODS:
A total of 108 Sprague Dawley (SD) rats were randomly divided into 2 parts experiment and 9 subgroups (part 1:Sham group, SAH group, SAH+NAC group, SAH+vehicle group; part 2: Sham group, SAH group, SAH+lv-SENP3 group, SAH+lv-null group, SAH+NS group). 7 days before SAH, lentivirus was administrated into rats׳ left lateral ventricle to down-regulate SENP3. Experimental SAH was imitated by injection with 0.3ml nonheparinized autoblood into the prechiasmatic cistern. MDA levels, SOD activities, and GSH contents were detected to evaluate oxidative stress level. SENP3 and cleaved caspase 3 were detected by western blot, apoptosis was observed by TUNEL staining.
RESULTS:
High oxidative stress level following SAH induced rising of SENP3. And inhibition of SENP3 by lentivirus induces suppression of apoptosis in experimental subarachnoid hemorrhage in rats.
CONCLUSION:
When SENP3 accumulated by high oxidative stress, caspase 3 activated subsequently. And it leads to more severe apoptosis than physiological.
Copyright © 2015 Elsevier B.V. All rights reserved.
AIMS:
Altered drug disposition has been associated with inflammation and diabetes, leading to the alteration of drug efficacy and toxicity. Carboxylesterases are major hydrolytic enzymes in the liver, catalyzing the hydrolytic biotransformation of numerous therapeutic agents. Therefore, how glucose affects the regulation of carboxylesterases by interleukin-6 (IL-6) and lipopolysaccharide (LPS) were investigated.
MAIN METHODS:
Primary mouse hepatocytes were cultured. Protein levels were measured by Western blot or enzyme linked immunosorbent assay (ELISA), while confocal laser scanning microscope and flow cytometry were used to confirm the activation of pregnane X receptor (PXR). Carboxylesterase activity was evaluated by enzymatic and toxicological assays.
KEY FINDINGS:
Elevated glucose (11 or 25 mM) significantly increased carboxylesterase expression compared to 5.6 mM glucose. Carboxylesterase expression and activity were inhibited by LPS or IL-6 in 25 mM glucose, but stimulated in 5.6 mM glucose. The altered expression of carboxylesterases was not consistent with the activation of nuclear factor kappa B (NFκB) but repeatedly with the expression and activation of pregnane X receptor (PXR). The altered activation of PXR was further evidenced by the differential subcellular translocation and the expression of its target gene multidrug resistance 1 (MDR1). It implies that PXR, instead of inflammatory signaling, mediates the regulation of carboxylesterases by inflammatory mediators in different glucose concentrations.
SIGNIFICANCE:
The findings contribute to clarify the regulation of carboxylesterases by inflammatory mediators, and indicate that carboxylesterase-involved drug metabolism and drug-drug interactions in diabetes should be reevaluated according to the intensity of inflammatory reactions and hyperglycemia.
Copyright © 2014 Elsevier Inc. All rights reserved.
The goal of this study was to evaluate the potential involvement of melatonin in the activation of the nuclear factor erythroid 2-related factor 2 and antioxidant-responsive element (Nrf2-ARE) signaling pathway and the modulation of antioxidant enzyme activity in an experimental model of traumatic brain injury (TBI). In experiment 1, ICR mice were divided into four groups: sham group, TBI group, TBI + vehicle group, and TBI + melatonin group (n = 38 per group). Melatonin (10mg/kg) was administered via an intraperitoneal (ip) injection at 0, 1, 2, 3, and 4h post-TBI. In experiment 2, Nrf2 wild-type (Nrf2(+/+) group) and Nrf2-knockout (Nrf2(-/-) group) mice received a TBI insult followed by melatonin administration (10mg/kg, ip) at the corresponding time points (n = 35 per group). The administration of melatonin after TBI significantly ameliorated the effects of the brain injury, such as oxidative stress, brain edema, and cortical neuronal degeneration. Melatonin markedly promoted the translocation of Nrf2 protein from the cytoplasm to the nucleus; increased the expression of Nrf2-ARE pathway-related downstream factors, including heme oxygenase-1 and
NAD(P)H:
quinone oxidoreductase 1; and prevented the decline of antioxidant enzyme activities, including superoxide dismutase and glutathione peroxidase. Furthermore, knockout of Nrf2 partly reversed the neuroprotection of melatonin after TBI. In conclusion, melatonin administration may increase the activity of antioxidant enzymes and attenuate brain injury in a TBI model, potentially via mediation of the Nrf2-ARE pathway.
Copyright © 2014 Elsevier Inc. All rights reserved.
Luteolin has recently been proven to exert neuroprotection in a variety of neurological diseases; however, its roles and the underlying mechanisms in traumatic brain injury are not fully understood. The present study was aimed to investigate the neuroprotective effects of luteolin in models of traumatic brain injury (TBI) and the possible role of the Nrf2-ARE pathway in the putative neuroprotection. A modified Marmarou׳s weight-drop model in mice and the scratch model in mice primary cultured neurons were used to induce TBI. We determined that luteolin significantly ameliorated secondary brain injury induced by TBI, including neurological deficits, brain water content, and neuronal apoptosis. Furthermore, the level of malondialdehyde (MDA) and the activity of glutathione peroxidase (GPx) were restored in the group with luteolin treatment. in vitro studies showed that luteolin administration lowered the intracellular reactive oxygen species (ROS) level and increased the neuron survival. Moreover, luteolin enhanced the translocation of Nrf2 to the nucleus both in vivo and in vitro, which was proved by the results of Western blot, immunohistochemistry, and electrophoretic mobility shift assay (EMSA). Subsequently upregulation of the expression of the downstream factors such as heme oxygenase 1 (HO1) and
NAD(P)H:
quinone oxidoreductase 1 (NQO1) was also examined. However, luteolin treatment failed to provide neuroprotection after TBI in Nrf2(-/-) mice. Taken together, these in vivo and in vitro data demonstrated that luteolin provided neuroprotective effects in the models of TBI, possibly through the activation of the Nrf2-ARE pathway.
Copyright © 2014 Elsevier Inc. All rights reserved.
AIM:
Paeonol (2'-hydroxy-4'-methoxyacetophenone) from Cortex moutan root is a potential therapeutic agent for atherosclerosis. This study sought to investigate the mechanisms underlying anti-inflammatory effects of paeonol in rat vascular endothelial cells (VECs) in vitro.
METHODS:
VECs were isolated from rat thoracic aortas. The cells were pretreated with paeonol for 24 h, and then stimulated with ox-LDL for another 24 h. The expression of microRNA-21 (miR-21) and PTEN in VECs was analyzed using qRT-PCR. The expression of PTEN protein was detected by Western blotting. TNF-α release by VECs was measured by ELISA.
RESULTS:
Ox-LDL treatment inhibited VEC growth in dose- and time-dependent manners (the value of IC50 was about 20 mg/L at 24 h). Furthermore, ox-LDL (20 mg/L) significantly increased miR-21 expression and inhibited the expression of PTEN, one of downstream target genes of miR-21 in VECs. In addition, ox-LDL (20 mg/L) significantly increased the release of TNF-α from VECs. Pretreatment with paeonol increased the survival rate of ox-LDL-treated VECs in dose- and time-dependent manners. Moreover, paeonol (120 μmol/L) prevented ox-LDL-induced increases in miR-21 expression and TNF-α release, and ox-LDL-induced inhibition in PTEN expression. A dual-luciferase reporter assay showed that miR-21 bound directly to PTEN's 3'-UTR, thus inhibiting PTEN expression. In ox-LDL treated VECs, transfection with a miR-21 mimic significantly increased miR-21 expression and inhibited PTEN expression, and attenuated the protective effects of paeonol pretreatment, whereas transfection with an miR-21 inhibitor significantly decreased miR-21 expression and increased PTEN expression, thus enhanced the protective effects of paeonol pretreatment.
CONCLUSION:
miR-21 is an important target of paeonol for its protective effects against ox-LDL-induced VEC injury, which may play critical roles in development of atherosclerosis.
BACKGROUND:
Epithelial-mesenchymal transition (EMT) is the major pathophysiological process in lung fibrosis observed in chronic obstructive pulmonary disease (COPD) and lung cancer. Smoking is a risk factor for developing EMT, yet the mechanism remains largely unknown. In this study, we investigated the role of Rac1 in cigarette smoke (CS) induced EMT.
METHODS:
EMT was induced in mice and pulmonary epithelial cells by exposure of CS and cigarette smoke extract (CSE) respectively.
RESULTS:
Treatment of pulmonary epithelial cells with CSE elevated Rac1 expression associated with increased TGF-β1 release. Blocking TGF-β pathway restrained CSE-induced changes in EMT-related markers. Pharmacological inhibition or knockdown of Rac1 decreased the CSE exposure induced TGF-β1 release and ameliorated CSE-induced EMT. In CS-exposed mice, pharmacological inhibition of Rac1 reduced TGF-β1 release and prevented aberrations in expression of EMT markers, suggesting that Rac1 is a critical signaling molecule for induction of CS-stimulated EMT. Furthermore, Rac1 inhibition or knockdown abrogated CSE-induced Smad2 and Akt (PKB, protein kinase B) activation in pulmonary epithelial cells. Inhibition of Smad2, PI3K (phosphatidylinositol 3-kinase) or Akt suppressed CSE-induced changes in epithelial and mesenchymal marker expression.
CONCLUSIONS AND GENERAL SIGNIFICANCE:
Altogether, these data suggest that CS initiates EMT through Rac1/Smad2 and Rac1/PI3K/Akt signaling pathway. Our data provide new insights into the fundamental basis of EMT and suggest a possible new course of therapy for COPD and lung cancer.
Copyright © 2014 Elsevier B.V. All rights reserved.
BACKGROUND:
Traumatic brain injury (TBI) is a worldwide health problem, identified as a major cause of death and disability. Increasing evidence has shown that oxidative stress plays an important role in TBI pathogenesis. The antioxidant transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), is a known mediator in protection against TBI-induced brain damage. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), a novel Nrf2 activator, can protect against TBI-induced oxidative stress.
METHODS:
Adult male imprinting control region mice were randomly divided into three groups: (1) sham + vehicle group; (2) TBI + vehicle group; and (3) TBI + tBHQ group. Closed-head brain injury was applied using the Feeney weight-drop method. We accessed the neurologic outcome of mice at 24 h after TBI, and subsequently measured protein levels of Nrf2 and the NOX2 subunit of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase), the concentration of malondialdehyde, superoxide dismutase activity, and brain edema.
RESULT:
The NOX2 protein level was increased fivefold in the TBI + vehicle group, whereas pretreatment with tBHQ markedly attenuated the NOX2 protein expression relative to that in the TBI + vehicle group. TBI increased Nrf2 formation by 5% compared with the sham group, whereas treatment with tBHQ further upregulated the Nrf2 protein level by 12% compared with the sham group. The level of the oxidative damage marker malondialdehyde was reduced by 29% in the TBI + tBHQ group compared with the TBI + vehicle group, Moreover, pretreatment with tBHQ significantly increased the antioxidant enzyme superoxide dismutase activity. Administration of tBHQ also significantly decreased TBI-induced brain edema and neurologic deficits.
CONCLUSIONS:
Pretreatment with tBHQ effectively attenuated markers of cerebral oxidative stress after TBI, thus supporting the testing of tBHQ as a potential neuroprotectant and adjunct therapy for TBI patients.
Copyright © 2014 Elsevier Inc. All rights reserved.
STUDY QUESTION:
Do dehydroepiandrosterone (DHEA)-treated rats with polycystic ovary syndrome (PCOS) demonstrate a high level of fibrosis in ovarian and uterine tissues?
SUMMARY ANSWER:
DHEA induces ovarian and uterine hyperfibrosis in rats, probably involving a transforming growth factor-β (TGF-β)-dependent mechanism.
WHAT IS KNOWN ALREADY:
Chronic inflammation is the typical cause of fibrosis and is involved in the pathophysiological process of PCOS. Patients with PCOS are reported to have a higher serum level of TGF-β, a well-characterized key pro-fibrotic factor. Fibrillin-3, a protein capable of interacting with TGF-β, has been reported to be partially responsible for the fetal origin of PCOS.
STUDY DESIGN, SIZE, DURATION:
Female Sprague-Dawley rats were treated with a vehicle control or DHEA for 35 days, with subsequent analyses of changes in morphology and gene expression in ovarian and uterine tissues. Rescue groups treated with metformin or simvastatin and their corresponding controls were also analyzed. A total of 80 rats were included.
PARTICIPANTS/MATERIALS, SETTING, METHODS:
The PCOS model was induced by daily administration of DHEA s.c. to 3-week-old female rats, and the rescue groups were injected daily with either metformin or simvastatin in addition to DHEA. Serum steroid hormone levels were measured by enzyme-linked immunosorbent assay. Samples were stained with hematoxylin and eosin for histological morphology, and Sirius Red and immunohistochemistry for revealing collagens. The expression of fibrosis-related genes was analyzed both at mRNA (real-time RT-PCR) and protein (western blot) levels.
MAIN RESULTS AND THE ROLE OF CHANCE:
DHEA-induced rats with PCOS exhibited significantly higher levels of fibrosis (collagen IV) in both ovarian and uterine tissues. In ovarian tissue, the expression of connective tissue growth factor (CTGF) increased following DHEA treatment at both mRNA and protein levels (P < 0.05, P < 0.001 versus controls, respectively). Similar results versus controls were obtained at a protein level for TGF-β (P < 0.01) and mRNA level for fibronectin (P < 0.05) and angiotensin-II (P < 0.05). Likewise, in uterine tissue, the protein levels of both CTGF and TGF-β were higher than controls following DHEA treatment (P < 0.05). Treatment with either metformin or simvastatin attenuated the fibrosis progression induced by DHEA exposure, as evidenced by a reduction of TGF-β, plus CTGF or not, in both ovarian and uterine tissues.
LIMITATIONS, REASONS FOR CAUTION:
The particular mechanism involved in the DHEA-induced fibrosis was not fully revealed.
WIDER IMPLICATIONS OF THE FINDINGS:
Ovarian and uterine hyperfibrosis may occur in patients with PCOS and result in anovulation or other PCOS-related phenotypes. Anti-fibrotic therapy, for example metformin treatment, may be beneficial for patients with PCOS.
STUDY FUNDING/COMPETING INTEREST(S):
This study was supported by the National Natural Science Foundation of China (81170541) and the Natural Basic Research Program of China (973 program 2010CB945103). The authors declare no conflicts of interest.
BACKGROUND AND PURPOSE:
Beta-amyloid (Aβ)-mediated inflammation contributes to the progression and chronicity of Alzheimer's disease (AD), although the exact mechanism remains unclear. This study aimed to investigate whether diammonium glycyrrhizinate (DG) could inhibit Aβ-induced inflammation in vitro and in vivo and to explore the underlying mechanisms.
METHODS:
Aβ(1-42) was injected to bilateral hippocampus of mice to make the AD models in vivo. The levels of mRNA and protein of inflammatory cytokines were measured by real-time PCR and Western blotting, respectively. The viability of SH-SY5Y and HT-22 cells was determined by MTT. NF-κB p65 translocation was analyzed by Western blotting and immunostaining. Phosphorylation of ERK, p38, and JNK was tested by Western blotting.
RESULTS:
DG suppressed Aβ(1-42) -induced activation of microglia and inflammation in vitro and in vivo. The media from Aβ(1-42) -activated microglia decreased the viability of SH-SY5Y and HT-22 cells, but it was rescued when pretreated with DG. DG could inhibit the activation of MAPK and NF-κB signaling pathways and attenuate the memory deficits in Aβ(1-42) -induced AD mice.
CONCLUSIONS:
DG protects Aβ(1-42) -induced AD models in vitro and in vivo through reducing activation of microglia and inflammation, which may be involved in MAPK and NF-κB pathways.
© 2012 Blackwell Publishing Ltd.
AIMS:
In this study, we investigated the peripheral mechanisms underlying the metabolic side effects of fluoxetine (FLX) by focusing on hepatic lipid metabolism.
METHODS:
Primary mouse hepatocytes were prepared from male mice by the two-step perfusion method. The lipid accumulation in primary mouse hepatocytes was analyzed via neutral oil staining. And the lipid metabolism enzymes were determined with RT-PCR and Western blot.
RESULTS:
Fluoxetine significantly induced the lipid accumulation in primary mouse hepatocytes. Moreover, FLX increased the acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase (FAS) expression, which are important enzymes in lipogenesis. Oppositely, Fluoxetine significantly decreased the carboxylesterase 3 (CES3) and carboxylesterase 1 (CES1) expression, which are related to lipolysis. Further study demonstrated FLX-activated SREBP1c, which is one of the most important transcription factors conducting coordinated transcriptional regulation of lipogenesis gene such as ACC1 and FAS. And the increase of lipogenesis gene (ACC1) was abolished by SB203580 but not by pyrrolidine dithiocarbamate (PDTC), suggesting through p38-MAPK pathway.
CONCLUSION:
Fluoxetine induces hepatic lipid accumulation via both promotion of the SREBP1c-related lipogenesis and reduction of lipolysis in primary mouse hepatocytes.
© 2012 Blackwell Publishing Ltd.
PURPOSE:
In this study, the effect of heparin-derived oligosaccharide (HDO) on vascular endothelial growth factor (VEGF) induced vascular smooth muscle cell (VSMC) proliferation and the signal transduction mechanisms involved were investigated.
METHODS:
MTT assays were used to measure VSMC proliferation, flow cytometry to analyze cell cycle distribution, RT-PCR for detection of gene transcript levels, and cell-based ELISA, Western blotting and immunocytochemical methods to detect the expression of PKC-α, ERK 1/2, p-ERK 1/2, Akt, p-Akt, p-PDK1 and p-GSK-3β.
RESULTS:
HDO at concentrations of 0.01, 0.1 and 1 μmol·L(-1) dose-dependently inhibited VEGF-induced VSMC proliferation with inhibition indices of 6.8 %, 13.1 % and 28.9 %, respectively. Similar concentrations of HDO dose-dependently decreased the percentage of VEGF-induced cells in S phase to 3.6 %, 3.4 %, and 5.4 %, while increasing that of cells arrested in the G0/G1 phase to 80 %, 82 % and 83.6 %. HDO at 0.01, 0.1 or 1 μmol·L(-1) inhibited VEGF-induced PKC-α mRNA expression, with inhibition indices of 9.2 %, 16.1 % and 54.0 %. HDO at 0.1 or 1 μmol·L(-1) inhibited VEGF-induced proto-oncogene mRNA expression, with inhibition indices of 5.2 % and 6.6 % for c-jun, 8.8 % and 11.6 % for c-myc, and 6.5 % and 11.9 % for c-fos, respectively. Additionally, treatment with 0.01, 0.1 or 1 μmol·L(-1) HDO, inhibited VEGF-induced expression of some proliferation related proteins with inhibition indices of 33.2 %, 56.3 % and 77.0 % for PKC-α, 33.7 %, 38.7 % and 53.2 % for p-Akt, 3.5 %, 24.2 % and 49.3 % for p-ERK 1/2, 39.2 %, 71.8 % and 80.7 % for p-PDK 1 and 41.4 %, 89.4 % and 92.4 % for p-GSK-3β, respectively. The results showed that HDO inhibited PKC-α, c-jun, c-fos and c-myc mRNA transcription, and also down-regulated phosphorylation levels of ERK 1/2 and Akt.
CONCLUSION:
Our study demonstrates that HDO inhibits transcription of proliferation-related proto-oncogenes and arrests G1/S transition through inhibition of the PKC, MAPK and Akt/PI3K pathways in association with inhibition of VSMC proliferation. This altered molecular signature may explain one mechanism of HDO-mediated inhibition of VSMC proliferation.
PURPOSE:
MicroRNAs (miRNAs) are short non-coding RNA molecules, which post-transcriptionally regulate genes expression and play crucial roles in diverse biological processes. Recent studies have shown that dysregulation of miRNAs might modulate the resistance of cancer cells to anti-cancer drugs, yet the modulation mechanism is not fully understood. We aimed to investigate the possible role of miRNAs in the development of multidrug resistance (MDR) in human gastric and lung cancer cell lines.
METHODS:
miRNA Quantitative real-time PCR was used to detect the different miRNA expression levels between drug resistant and parental cancer cells. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to test the drug-resistant phenotype changes in cancer cells via over or downregulation of miRNAs. Dual-luciferase activity assay was used to verify the target genes of miRNAs. Western blot analysis and apoptosis assay were used to elucidate the mechanism of miRNAs on modulating drug resistance in cancer cells.
RESULTS:
miR-200bc/429 cluster was downregulated, while BCL2 and XIAP were upregulated in both MDR SGC7901/VCR (vincristine) and A549/CDDP (cisplatin) cells, compared with the parental SGC7901 and A549 cells, respectively. Overexpression of miR-200bc/429 cluster sensitized SGC7901/VCR and A549/CDDP cells to anti-cancer drugs, respectively. Both BCL2 and XIAP 3'-UTR reporters constructed in MDR cells suggested that BCL2 and XIAP were the common target genes of the miR-200bc/429 cluster. Enforced miR-200bc/429 cluster expression reduced BCL2 and XIAP protein level and sensitized both MDR cells to VCR-induced and CDDP-induced apoptosis, respectively.
CONCLUSIONS:
Our findings first suggest that miR-200bc/429 cluster could play a role in the development of MDR in both gastric and lung cancer cell lines, at least in part by modulation of apoptosis via targeting BCL2 and XIAP.