ABSTRACT
To study the effect of HCV core protein on the interferon-induced antiviral genes expression and its mechanisms. Methods HepG2 cells were transiently transfected with HCV core protein expression plasmid and the blank plasmid respectively. RT-PCR was used to analyze the effect of HCV core protein on PKR and 2'-5'OAS expression. The effect of HCV core protein on ISRE-medicated gene expression was detected by luciferase activity assay. Western-blot assay was performed to observe the change of mRNA and protein levels of SOCS3, STAT1 and p-STAT1 following HCV core expression. In the presence of HCV core protein, the transcription of PKR and 2'-5' OAS are down-regulated. ISRE-medicated reporter gene expression and STAT1 phosphorylation were inhibited. The transcription and expression of SOCS3 were induced compared with blank plasmid-transfected group. In HepG2 cells, HCV core protein can down-regulate the expression of some interferon-induced antiviral genes, which involves the induction of SOCS3 and the inhibition of STAT1 phosphorylation.
Subject(s)
Humans , 2',5'-Oligoadenylate Synthetase , Genetics , Metabolism , Carcinoma, Hepatocellular , Pathology , Down-Regulation , Hepacivirus , Genetics , Metabolism , Interferon-Stimulated Gene Factor 3 , Genetics , Metabolism , Interferon-alpha , Genetics , Allergy and Immunology , Liver Neoplasms , Pathology , Protein Kinases , Genetics , Metabolism , STAT1 Transcription Factor , Genetics , Metabolism , STAT2 Transcription Factor , Genetics , Metabolism , Transcription, Genetic , Transfection , Tumor Cells, Cultured , Viral Core Proteins , Genetics , Metabolism , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To study the mechanism of signal transduction in anti-HBV action of IFN-alpha.</p><p><b>METHODS</b>The HBV DNA in HepG 2.2.15 cell line supernatant with/without IFNalpha-2b were monitored by fluorescence real-time quantitive PCR. STAT1, STAT2, ISGF3-gamma, PKR, 2'5'-OAS mRNA levels from HepG 2 and HepG 2.2.15 cell lines that were treated with/without IFNalpha-2b at different times were detected by semi-quantitive RT-PCR. And the ISGF3-gamma protein was detected by Western blot. Then, these items were detected again after inhibiting the JAK-STAT pathway with genistein.</p><p><b>RESULTS</b>The HBV DNA in 2215 supernatant that were treated with IFNalpha-2b for 8 hours decreased 0.72 log 10 copies/ml. But the basal levels of DNA in cells pretreated with genistein? followed by IFNalpha-2b did not decrease. The STAT1, STAT2, ISGF3-gamma, 2'5'-OAS, PKR mRNA levels were upregulated by IFNalpha-2b. The same phenomena were observed with STAT1, STAT2, ISGF3-gamma mRNA when pretreated with genistein then treated with IFNalpha-2b, but the levels of 2'5'-OAS, PKR mRNA were decreased in this situation. The expression of the protein of ISGF3-gamma was also augmented by IFNalpha-2b, and was blocked by genistein.</p><p><b>CONCLUSION</b>The JAK-STAT pathway seems to be a critical pathway in IFNalpha-2b action against HBV? and ISGF3 is most probably a key factor of the route.</p>