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IFN-stimulated Genes (IFN-stimulat + gene)
Selected AbstractsRole of ISGF3 in modulating the anti-hepatitis B virus activity of interferon-alpha in vitroJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 11 2008Quan Zhang Abstract Background and Aim:, Although interferon-, (IFN-,) is an effective treatment for hepatitis B virus (HBV) infection, its precise mechanism of action has not been identified. In this study, we investigated the role of signal transduction pathways in the activation of anti-HBV responses mediated by IFN-,. Methods:, Using an oligo microarray, we found that four genes in the IFN-, signal pathway were markedly upregulated by IFN-, in human hepatoma cells regardless of whether they had been transfected with a plasmid containing the HBV genome: signal transducers and activators of transcription 1 (STAT1), interferon regulatory factor-9 (IRF-9, also called ISGF3, or P48), IFN-,-inducible protein 15 (IFI-15) and IFN-,-inducible protein 6,16 (IFI-6-16). We also investigated the role of IFN-stimulated gene factor3 (ISGF3) complex in IFN-,-mediated anti-HBV responses in human hepatoma cells by measuring the mRNA of the three genes within ISGF3 (STAT1, STAT2 and IRF-9) using semiquantitative reverse-transcription PCR (RT-PCR), and expression of the three proteins by western blot, and the mRNA and protein of dsRNA-dependent protein kinase (PKR). Results:, STAT1, STAT2, IRF-9 and PKR mRNA as well as protein levels were upregulated by IFN-, treatment. When cells were pretreated with genistein, STAT1, STAT2 and IRF-9 mRNA levels remained unchanged after IFN-, stimulation, but PKR mRNA levels decreased, and the expression of the STAT1, P-STAT2, IRF-9 and PKR proteins decreased. Levels of HBV DNA decreased in the supernatants of cells treated with IFN-,, while ISGF3 levels increased. The quantity of HBV DNA remained unchanged by pretreating with genistein. Conclusions:, These observations suggested that the Janus tyrosine kinase,STAT (JAK-STAT) pathway may play a major role in mediating the effects of IFN-, against HBV, and that ISGF3 might be a key factor. [source] Hepatitis C virus replication is inhibited by 22,-methoxyolean-12-ene-3,, 24(4,)-diol (ME3738) through enhancing interferon-,,HEPATOLOGY, Issue 1 2008Yoichi Hiasa A derivative of soyasapogenol, 22,-methoxyolean-12-ene-3,, 24(4,)-diol (ME3738), ameliorates liver injury induced by Concanavalin A in mice. We examined whether ME3738 has independent antiviral effects against hepatitis C virus (HCV) using an established HCV replication model that expresses the full-length genotype 1a HCV complementary DNA plasmid (pT7-flHCV-Rz) under the control of a replication-defective adenoviral vector expressing T7 polymerase. Hepatocellular carcinoma (HepG2) cells, human hepatoma (Huh7) cells, or monkey kidney (CV-1) cells were transfected with pT7-flHCV-Rz, and infected with adenoviral vector expressing T7 polymerase. ME3738 or interferon-, (IFN-,) was added thereafter and then protein and RNA were harvested from the cells at 9 days after infection. HCV-positive and HCV-negative strands were measured by real-time reverse-transcription polymerase chain reaction and HCV core protein expression was measured using an enzyme-linked immunosorbent assay. The messenger RNA levels of innate antiviral response-related genes were assessed using real-time reverse-transcription polymerase chain reaction. ME3738 dose-dependently reduced HCV-RNA and core protein in hepatocyte-derived cell lines. The antiviral effect was more pronounced in HepG2 than in Huh7 cells. ME3738 increased messenger RNA levels of interferon-, (IFN-,) and of IFN-stimulated genes (2,-5, oligoadenylate synthetase, myxovirus resistance protein A [MxA]). Interferon-, knockdown by small interfering RNA abrogated the anti-HCV effect of ME3738. Moreover, the anti-HCV effects were synergistic when ME3738 was combined with IFN-,. Conclusion: ME3738 has antiviral effects against HCV. The enhancement of autocrine IFN-, suggests that ME3738 exerts antiviral action along the type I IFN pathway. This anti-HCV action by ME3738 was synergistically enhanced when combined with IFN-,. ME3738 might be a useful anti-HCV drug either with or without IFN-,. (HEPATOLOGY 2008.) [source] Regulation of innate immunity against hepatitis C virus infectionHEPATOLOGY RESEARCH, Issue 2 2008Takeshi Saito Chronic hepatitis C virus (HCV) infection is a global public health problem. HCV infection is treated with type I interferon (IFN), a natural product that is produced by cells during virus infection as a result of innate immune signaling events. The secreted IFN alert the surrounding cells to turn on an "antiviral state" that resists infection. In general, the role of innate immune response is to suppress viral replication and to induce cytokines and other factors that promote adaptive immunity and the resolution of infection. The mechanisms by which the innate immune response and IFN actions limit HCV infection are not well defined, but are likely to involve the function of specific IFN-stimulated genes. HCV also copesintensively with immune responses in order to establish persistent infection. Recent studies reveal that a other viruses use similar tactics to regulate the antiviral innate immune response. In the case of HCV, innate immune signaling is strictly controlled by the viral NS3/4A protease, resulting in the disruption of IFN production. Here, we summarize the current understanding of how HCV evades the innate immune system. [source] Non-conventional signal transduction by type 1 interferons: The NF-,B pathwayJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2007Ziyun Du Abstract Type I interferons (IFNs) regulate diverse cellular functions by modulating the expression of IFN-stimulated genes (ISGs) through the activation of the well established signal transduction pathway of the Janus Kinase (JAK) and signal transducers and activators of transcription (STAT) proteins. Although the JAK,STAT signal transduction pathway is critical in mediating IFN's antiviral and antiproliferative activities, other signaling pathways are activated by IFNs and regulate cellular response to IFN. The NF-,B transcription factor regulates the expression of genes involved in cell survival and immune responses. We have identified a novel IFN mediated signal pathway that leads to NF-,B activation and demonstrate that a subset of ISGs that play key roles in cellular response to IFN is regulated by NF-,B. This review focuses on the IFN-induced NF-,B activation pathway and the role of NF-,B in ISG expression, antiviral activity and apoptosis, and the therapeutic application of IFN in cancer and infectious disease. J. Cell. Biochem. 102: 1087,1094, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||