Abstract
Objective To observe the effects of HCV protein, NS3 and NS5A on IFN-β in HepG2 cells and its regulation mechanism.
Methods Human liver hepatocellular carcinoma cells HepG2 were transfected with recombinant eukaryotic plasmid pcDNA3.1/myc-His-core, NS3 or NS5A to overexpress these proteins, and the expression of IFN-β were detected by qRT-PCR, Western blotting and ELISA. Luc2P reporter plasmids pGL4.10-IFNβ-P were constructed and transfected into HepG2 cells, and the activity of IFN-β promoter were determined through luciferase assay for regulation mechanism study.
Results Both mRNA level and protein expression of IFN-β were significantly decreased (P ＜ 0.05) in the presence of NS3 or NS5A protein. Luciferase assay revealed that NS3 or NS5A protein downregulated IFN-β promoter activity (P ＜ 0.05). Meanwhile, HCV core protein had little effect on IFN-β expression.
Conclusions HCV protein NS3 and NS5A could inhibit innate IFN-β expression and thus escape immune selection and hinder the host immune responses.
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