Anti-Stat1 Antibody (A24919)

Bluetongue virus (BTV) causes a non-contagious, arthropod-transmitted disease in wild and domestic ruminants, such as sheep. In this study, we used iTRAQ labeling coupled with LC-MS/MS for quantitative identification of differentially expressed proteins in BTV-infected sheep testicular (ST) cells. Relative quantitative data were obtained for 4455 proteins in BTV- and mock-infected ST cells, among which 101 and 479 proteins were differentially expressed at 24 and 48 h post-infection, respectively, indicating further proteomic changes during the later stages of infection. Ten corresponding genes of differentially expressed proteins were validated via real-time RT-PCR. Expression levels of three representative proteins, eIF4a1, STAT1 and HSP27, were further confirmed via western blot analysis. Bioinformatics analysis disclosed that the differentially expressed proteins are primarily involved in biological processes related to innate immune response, signal transduction, nucleocytoplasmic transport, transcription and apoptosis. Several upregulated proteins were associated with the RIG-I-like receptor signaling pathway and endocytosis. To our knowledge, this study represents the first attempt to investigate proteome-wide dysregulation in BTV-infected cells with the aid of quantitative proteomics. Our collective results not only enhance understanding of the host response to BTV infection but also highlight multiple potential targets for the development of antiviral agents.

Cerebral ischemic injury involves a variety of cellular and molecular events. Signal transducers and activators of transcription-1 (STAT-1) activation is associated with neuronal cell death and contributes to ischemic injury. The effects of fludarabine, a specific inhibitor of STAT1 protein, on cerebral ischemic/reperfusion (I/R) injury were studied in a rat model. Rats subjected to I/R injury were either treated with intra-cerebroventricular injection of fludarabine (5,000 μM, 10 μl) or saline 20 min before middle cerebral artery occlusion (MCAO). MR examinations including T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and perfusion-weighted imaging (PWI) were performed after I/R period. Then rat brains were sectioned for triphenyltetrazolium chloride (TTC) stains, analyzed by Western blot and TUNEL staining of apoptosis. It was found that fludarabine treatment decreased the infarct volume of the cerebrum and the number of apoptotic neural cells in the ischemic brain. Compared to saline-treated group, the apparent diffusion coefficient (ADC) and cerebral blood volume (CBV) in the ischemic region were greater, and the mean transit time (MTT) was shortened in the fludarabine-treated group. Moreover, fludarabine inhibited the expression level of phosphorylated STAT1 (P-STAT1) in neural cells after I/R injury, whereas the expression of phosphorylated STAT3 (P-STAT3) was increased. Therefore, we concluded that fludarabine administrated in early stage of cerebral ischemia had neuroprotective effects, and the underlying mechanism could be mediated through inhibiting STAT1 phosphorylation and activating the cross regulation between STAT1 and STAT3 in neural cells.

Signal transducer and activator of transcription 1 (STAT1) regulates cell proliferation and survival. The present study aimed to investigate the role of STAT1 in the development and progression of human hepatocellular carcinoma (HCC). The levels of STAT1 expression in 36 HCC and 12 non-HCC liver tissues were examined by immunohistochemistry. The effect of STAT1 overexpression or silencing on the proliferation and apoptosis of HCC cells was determined by MTT and flow cytometric assays. The effect of STAT1 overexpression or silencing on the levels of p53 and cyclin E expression was determined by quantitative PCR and western blot assays. The level of STAT1 expression in the HCC tissues was significantly lower compared to the level in the non-HCC liver tissues and was negatively associated with the histological grade of HCC and serum HBsAg, anti-HCV and α-fetoprotein positivity in HCC patients. Induction of STAT1 overexpression significantly inhibited HepG2 cell proliferation and enhanced HCC cell apoptosis, accompanied by upregulation of p53 expression and STAT1 phosphorylation, but a reduction in cyclin E expression in HepG2 cells. In contrast, knockdown of STAT1 by introduction of STAT1-specific siRNA promoted HepG2 cell proliferation, but inhibited HCC cell apoptosis, accompanied by significant downregulation of p53 expression, but enhancement of cyclin E expression in vitro. Our data suggest that STAT1 may inhibit HCC growth by regulating p53-related cell cycling and apoptosis.

Local hyperthermia has been successfully used in the treatment of viral warts by mechanisms that have largely remained unclear. Using an organotypic culture system, we found that hyperthermia at 42 °C and 45 °C could induce a significant increase in the transcriptional expression of interferon (IFN)-α, IFN-β and IFN-γ, in a temperature-dependent manner in condyloma acuminata (CA), but not in normal skin. Accordingly, local hyperthermia could enhance the expression of 2'-5' oligoadenylate synthase and double-stranded RNA (dsRNA)-dependent protein kinase, two antiviral enzymes downstream of the IFN-dependant pathway. Hyperthermia led to an increase in IFN-α/β receptor transcripts, and an increase in the levels in phospho-Stat1 and phospho-Stat2 in CA, though it had no influence on the levels of Jak1, Tyk2, Stat1 and Stat2 transcriptional expression. Local hyperthermia was proved effective in treating human papillomavirus-infected skin. These results suggested that hyperthermia took effect partly by inducing the expression of local endogenous IFN and partly by subsequent IFN-induced antiviral activity via Jak-STATs signalling pathway in CA.

BACKGROUND AIMS:

Mesenchymal stromal cells (MSCs) and regulatory T cells (Treg) have been successfully used in treating autoimmune diseases accompanied by abundant inflammatory cytokines such as interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Therefore, this work investigated the effects of IFN-γ and TNF-α on the ability of human placenta-derived mesenchymal stromal cells (hPMSCs) on inducing the differentiation of CD4(+)interleukin (IL)-10(+)and CD8(+)IL-10(+)Treg subsets.

METHODS:

Human PMSCs were co-cultured with T cells in the presence or absence of a trans-well system or anti- programmed death ligand-2 (PDL2) monoclonal antibody (mAb), respectively. CD4(+)IL-10(+)and CD8(+)IL-10(+)Treg subsets, as well as the levels of IL-10 in the supernatants, were detected on this basis. Examinations were conducted to explore the impact of IFN-γ and TNF-α on the expression of PDL2 in hPMSCs. In this process, flow cytometry, Western blot and reverse-transcriptase-polymerase chain reaction were used.

RESULTS:

CD4(+)IL-10(+)and CD8(+)IL-10(+)Treg subsets from T cells either non-activated or activated by use of phytohaemagglutinin (PHA) or CD3/CD28mAb significantly increased in the presence of hPMSCs. However, these levels markedly decreased after blocking the expression of PDL2 in hPMSCs. IL-10 followed the same pattern. Furthermore, the percentages of CD4(+)IL-10(+) and CD8(+)IL-10(+)T cells also sharply declined under the trans-well system, whereas the percentages as well as the expression of PDL2 in hPMSCs oppositely raised after hPMSCs pre-stimulated by IFN-γ and TNF-α. IFN-γ could promote the expression of PDL2 partly through the JAK/STAT signaling pathway.

CONCLUSIONS:

IFN-γ and TNF-α could promote the ability of hPMSCs in inducing the differentiation of CD4(+)IL-10(+)and CD8(+)IL-10(+)Treg subsets and enhance the expression of PDL2 in hPMSCs. These would benefit the application of hPMSCs in clinical trials.

Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.