Anti-CREB (phospho-S133) Anticorps (A27337)

Previous studies showed that prostacyclin inhibited fibrosis. However, both receptors of prostacyclin, prostacyclin receptor (IP) and peroxisome proliferator-activated receptor (PPAR), are abundant in cardiac fibroblasts. Here we investigated which receptor was vital in the anti-fibrosis effect of prostacyclin. In addition, the possible mechanism involved in protective effects of prostacyclin against cardiac fibrosis was also studied. We found that beraprost, a prostacyclin analogue, inhibited angiotensin II (Ang II)-induced neonatal rat cardiac fibroblast proliferation in a concentration-dependent and time-dependent manner. Beraprost also suppressed Ang II-induced collagen I mRNA expression and protein synthesis in cardiac fibroblasts. After IP expression was knocked down by siRNA, Ang II-induced proliferation and collagen I synthesis could no longer be rescued by beraprost. However, treating cells with different specific inhibitors of PPAR subtypes prior to beraprost and Ang II stimulation, all of the above attenuating effects of beraprost were still available. Moreover, beraprost significantly blocked transforming growth factor β (TGF β) expression as well as Smad2 phosphorylation and reduced Smad-DNA binding activity. Beraprost also increased phosphorylation of cAMP response element binding protein (CREB) at Ser133 in the nucleus. Co-immunoprecipitation analysis revealed that beraprost increased CREB but decreased Smad2 binding to CREB-binding protein (CBP) in nucleus. In conclusion, beraprost inhibits cardiac fibroblast proliferation by activating IP and suppressing TGF β-Smad signal pathway.

Glucocorticoids are vital for life and regulate an array of physiological functions by binding to the ubiquitously expressed glucocorticoid receptor (GR, also known as NR3C1). Previous studies demonstrate striking breed differences in plasma cortisol levels in pigs. However, investigation into the breed-dependent GR transcriptional regulation is hampered by lacking porcine GR promoter information. In this study, we sequenced 5.3 kb upstream of the translation start codon of the porcine GR gene, and identified seven alternative 5'-untranslated exons 1-4, 1-5, 1-6, 1-7, 1-8, 1-9,10 and 1-11. Among all these mRNA variants, exons 1-4 and 1-5, as well as the total GR were expressed significantly (P<0.05) higher in the liver of newborn piglets of Large White (LW) compared with Erhualian, a Chinese indigenous breed. Overall level of CpG methylation in the region flanking exons 1-4 and 1-5 did not show breed difference. However, nuclear content of Sp1, p-CREB and GR in the liver was significantly (P<0.05) higher in LW piglets, associated with enhanced binding of p-CREB, and higher level of histone H3 acetylation in 1-4 and 1-5 promoters. In contrast, GR binding to promoters of exons 1-4 and 1-5 was significantly diminished in LW piglets, implicating the presence of negative GREs. These results indicate that the difference in the hepatic expression of GR transcript variants between two breeds of pigs is determined, at least partly, by the disparity in the binding of transcription factors and the enrichment of histone H3 acetylation to the promoters.

AIM:

The aim of this study was to study the effects of compound FLZ, a novel cyclic derivative of squamosamide from Annona glabra, on brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB)/cAMP response element-binding protein (CREB) signaling and neuronal apoptosis in the hippocampus of the amyloid precursor protein (APP)/presenilin-1 (PS1) double transgenic mice.

METHODS:

APP/PS1 mice at the age of 5 months and age-matched wild-type mice (WT) were intragastrically administered FLZ (150 mg/kg) or vehicle [0.05% carboxymethyl cellulose sodium (CMC-Na)] daily for 20 weeks. The levels of BDNF in the hippocampus of WT and APP/PS1 mice were then measured by immunohistochemistry and Western blot analysis. Neuronal apoptosis in mouse hippocampus was detected by Nissl staining. Expression of NGF, NT3, pTrkB (Tyr515)/TrkB, pAkt (Ser473)/Akt, pERK/ERK, pCREB (Ser133)/CREB, Bcl-2/Bax, and active caspase-3 fragment/caspase-3 in the hippocampus of WT and APP/PS1 mice was detected by Western blot analysis.

RESULTS:

Compared with vehicle-treated APP/PS1 mice, FLZ (150 mg/kg) significantly increased BDNF and NT3 expression in the hippocampus of APP/PS1 mice. In addition, FLZ promoted BDNF high-affinity receptor TrkB phosphorylation and activated its downstream ERK, thus increasing phosphorylation of CREB at Ser133 in the hippocampus of APP/PS1 mice. Moreover, FLZ showed neuroprotective effects on neuronal apoptosis by increasing the Bcl-2/Bax ratio and decreasing the active caspase-3 fragment/caspase-3 ratio in the hippocampus of APP/PS1 mice.

CONCLUSION:

FLZ exerted neuroprotection at least partly through enhancing the BDNF/TrkB/CREB pathway and inhibiting neuronal apoptosis in APP/PS1 mice, which suggests that FLZ can be explored as a potential therapeutic agent in long-term Alzheimer's disease therapy.

Bisphenol A (BPA) is an estrogenic environmental toxin widely used in the production of plastics and ubiquitous human exposure to this chemical has been proposed to be a potential risk to human health. Exposure to BPA can negatively impact sperm quality. However, the mechanism remains largely unknown. The objectives of this study were to assess the role of BPA on sperm quality and explore the possible mechanisms. The Wistar male rats (aged 28 days) were administered BPA by oral gavage for 28 days at dose of 50, 100 and 200 mg/kg/day; meanwhile, the negative control with corn oil (0 mg/kg/day BPA) and positive control with E2 at the dose of 100 μg/kg/day. The sperm density, sperm activity and sperm survival rate were analyzed byCASA system, and the sperm abnormality rate was analyzed by improved Papanicolaou stained. The protein expression levels of Src/p-Src, ERK1/2, p-ERK1/2 and CREB/p-CREB were detected by Western bolt. The results showed that the body weight gain, testes weight, testis coefficient, sperm density, sperm activity, sperm survival rate and protein expression levels of p-ERK1, p-ERK2 and p-CREB decreased, but the sperm abnormality rate increased with increasing BPA concentrations. There were positive correlations between sperm density, sperm activity and sperm survival rate with protein expression levels of p-ERK1, p-ERK2 and p-CREB, and negative correlations between sperm abnormality rate with the protein expression levels of p-ERK1, p-ERK2 and p-CREB. Results from the structural equation model demonstrated that BPA retained a significant negative effect to p-ERK, whereas p-ERK retained a significant positive effect to sperm quality and acted as the mediate variable. This study provides a novel insight regarding the potential role of p-ERK1 and p-ERK2 protein kinase on reproductive toxicity of BPA. The adverse effects of BPA on adult male sperm quality may be through the induction of the disruption of ERK signal pathway. However, additional research is needed to confirm our findings and to further test the suggested potential mechanisms.

Ubiquitin C-terminal hydrolase L1 (UCH-L1) is abundantly expressed in the brain and is critical for the normal function of synapses. cAMP response element binding protein (CREB) is a transcription factor which initiates the expression of proteins that related to the regulation of synaptic plasticity and memory function. Studies have shown that UCH-L1 can influence the expression and activity of CREB, but the underlying mechanisms remain unclear. In this study, we used UCH-L1 inhibitor LDN to treat mice hippocampal slices and found that UCH-L1 inhibition caused the dephosphorylation of CREB at Ser133 site. Meanwhile, hyperphosphorylation of microtubule-associated protein tau; increased expression of synaptic protein components of PSD-95 and synapsin-1, and decreased activity of tyrosine kinase Fyn were observed after UCH-L1 inhibition. Moreover, all these alternations have an influence on the normal function of N-methyl-D-aspartate (NMDA) receptor NR2B subunit which is likely to result in the dephosphorylation of CREB. We also found that LDN treatment mediated protein kinase A (PKA) deactivation was involved in the dephosphorylation of CREB. Thus, our study introduces a novel possible mechanism for elaborating the effects of UCH-L1 inhibition on the CREB activity and the implicated signaling pathways.

Nicorandil, an ATP-sensitive potassium (KATP) channel opener, is known to have protective effects on ischemic injury in heart and brain. One of the most important protective mechanisms is the anti-apoptotic effect on cardiomyocytes and neurons. This study explored the anti-apoptotic effect of nicorandil against neurotoxicity in SH-SY5Y cells overexpressing the Swedish mutant APP (APPsw) and the possible mechanisms involved. We used SH-SY5Y cells transiently transfected with APPsw as a cellular model of Alzheimer's disease. Cells were treated with nicorandil (0.1, 0.5, 1 mM) for 24 h with and without glibenclamide (10 μM), a KATP channel inhibitor. The cells were then collected for MTT, apoptosis assay, and Western blot. In addition, we also investigated the potential involvement of the PI3K/Akt pathway in nicorandil-mediated neuroprotection of APPsw cells. Our results showed that nicorandil dose-dependently increased cell viability and reduced the rate of apoptosis as measured by MTT assay and annexin V/PI staining. Western blot showed that nicorandil could upregulate Bcl-2 levels and downregulate Bax and caspase-3 expression. Further studies showed that nicorandil increased the levels of phospho-Akt and upregulated element-binding protein activity by PI3K activation. Applying a PI3K inhibitor, LY294002 blocked the protection. All these findings suggest that nicorandil might be a potential treatment option for Alzheimer's disease.

Picroside II, an iridoid glucoside found in the root of Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been demonstrated to reduce apoptosis in neuronal cells and other cell types. However, whether picroside II has a protective effect against cardiomyocyte apoptosis is poorly understood. In the present study, we investigated the cardioprotective role of picroside II and the underlying mechanisms in hypoxia/reoxygenation-induced cardiomyocyte apoptosis. The pretreatment with picroside II markedly attenuated hypoxia/reoxygenation-induced cell damage dose-dependently, which was evident by the increased cell viability and the corresponding decrease in lactate dehydrogenase release (LDH). The pretreatment with picroside II inhibited apoptosis confirmed by Annexin V-FITC staining, Hoechst 33258 nuclear staining and by assessment of caspase-3 activity. In addition, we found that picroside II not only increased the expression of Bcl-2, while decreasing Bax expression, but also augmented Akt and cAMP response element-binding protein (CREB) phosphorylation and ultimately inhibited hypoxia/reoxygenation-induced apoptosis. Furthermore, the protective effects of picroside II were abrogated by pretreatment of the cells with wortmannin or LY294002, a specific PI3K inhibitor. The present study suggests that picroside II inhibits hypoxia/reoxygenation-induced apoptosis in cardiomyocytes by activating the PI3K/Akt and CREB pathways and modulating expression of Bcl-2 and Bax.

Interleukin-6 (IL-6) is a pleiotropic cytokine secreted by macrophages and others and it has been proven to be a potential therapeutic target of RA. Norisoboldine (NOR) is the main isoquinoline alkaloid constituent in the dry roots of Lindera aggregata (Sims) Kosterm. (L. strychnifolia Vill.), which has long been used in traditional Chinese medicine for treating RA and other diseases. Our previous studies indicated that NOR was able to attenuate inflammation and joint destruction in collagen II-induced arthritis of mice. To further recognize the anti-rheumatoid potentials of NOR, the present study addressed whether and how NOR interfered with IL-6 production from fibroblast-like synoviocytes (FLS), key effector cells in the development and progression of RA. FLS, obtained from the synovial tissues of rats with adjuvant arthritis, showed incremental release of IL-6 after stimulated with IL-1β in vitro. NOR (10, 30, and 60 µM) could reduce the production of IL-6 in a concentration-dependent manner. It also down-regulated the phosphorylations of mitogen-activated protein kinases (MAPKs), protein kinase C (PKC), and transcriptional factor nuclear factor-κB (NF-κB)-p65 (ser 276) as well as cAMP response element-binding protein (CREB) in FLS. By using specific inhibitors, PKC was shown to be the upstream protein of MAPKs, and p38 MAPK was at the upstream of CREB. It was concluded that preventing IL-6 release from FLS might be an important mechanism for NOR displaying anti-RA property, and the action of NOR was relative to inhibition of PKC/MAPKs/p65/CREB pathways.

We described a prospective application of ligand-based virtual screening program SHAFTS to discover novel inhibitors for p90 ribosomal S6 protein kinase 2 (RSK2). Taking the putative 3D conformations of two weakly binding RSK2 NTKD inhibitors as query templates, SHAFTS was used to perform 3D similarity based virtual screening because of a lack of crystal structure of RSK2 protein, thus leading to the identification of several novel scaffolds that would have been missed by conventional 2D fingerprint methods. The most potent hit compounds show low micromolar inhibitory activities against RSK2. In particular, one of the hit compounds exhibits potent antimigration activity against the MDA-MB-231 tumor cell. The results exemplified SHAFTS' application in active enrichment and scaffold hopping, which is of general interest for lead identification in drug discovery endeavors and also provides novel scaffolds that lay the foundation for uncovering new RSK2 regulatory mechanisms.

CONTEXT:

Hydrosalpinx impairs endometrial receptivity and embryo implantation. However, the exact underlying mechanism remains elusive.

OBJECTIVE:

This study aimed to explore how an miR-133b-mediated mechanism controls endometrial receptivity and embryo attachment in the endometrium of women with hydrosalpinx.

DESIGN, SETTING, PATIENTS, AND INTERVENTIONS:

Ishikawa cells were treated with hydrosalpinx fluid (HF) from infertile patients and cultured for in vitro analysis. The attachment rates of BeWo spheroids and mouse embryos to Ishikawa cells were assayed.

PRIMARY OUTCOME MEASURE:

miR-133b, serum and glucocorticoid-regulated kinase 1 (SGK1), and homeobox A10 (HOXA10) expression levels were evaluated by quantitative real-time PCR and Western blot assays.

RESULTS:

The expression of miR-133b and HOXA10 was significantly down-regulated, whereas the miR-133b target gene SGK1 was up-regulated in mid-secretory endometrial tissues of women with hydrosalpinx and in HF-treated Ishikawa cells. Moreover, hydrosalpinx inhibited miR-133b expression through the activation of nuclear factor κB/p65, and SGK1 decreased miR-133b-induced HOXA10 expression by phosphorylating cAMP responsive element binding protein in Ishikawa cells. Our results also showed that miR-133b and HOXA10 contributed to BeWo spheroid adhesiveness, whereas SGK1 inhibited BeWo spheroid attachment to Ishikawa cells. Importantly, miR-133b overexpression reversed the HF-mediated impairment of embryo attachment in vitro.

CONCLUSIONS:

miR-133b directly targets SGK1 to reverse the hydrosalpinx-induced down-regulation of HOXA10 and to attenuate the impairment of embryo attachment in vitro.