The Effects Of MiR-122on The Pathogenesis Of Chronic Hepatitis C

Part Ⅰ Influence of miR-122on IFN-α treatment in HCVObjective:To explore the influence of miR-122on IFN-α treatment in HCV infection.Methods:1. Huh7.5.1cells infected with HCV were treated with miR-122mimics (20nmol/L,100nmol/L,400nmol/L) and/or IFN-α (1000IU/ml). The relative expression of HCV RNA was detected by Real-time polymerase chain reaction (PCR).2. Huh7.5.1cells were treated with different amounts of HCV (107copies,106copies,105copies) and/or IFN-α.Results:1. IFN-α suppressed the replication of HCV in a time-dependent manner, resulting in a～83%reduction of HCV at48h. MiR-122mimics facilitated replication of HCV RNA in a dose-dependent manner (P<0.05).2. The antiviral effect of IFN-α was inversely related to the level of miR-122mimics (20nmol/L,100nmol/L,400nmol/L),(73.3%±3.5%,64.67%±5.5%,56.33%±5.1%vs84%±4.5%, the latter two groups P<0.05). 3. The antiviral effect of IFN-a was inversely related to HCV load (105copies group vs107copies group, P<0.05).Conclusion:miR-122facilitates replication of HCV RNA in the cell culture system. Furthermore, miR-122may affect the antiviral therapy of IFN-a indirectly through modulating HCV load. Objective:To explore the influence of HCV and core protein on the expression of miR-122, using HCV cell culture model and HCV-core protein recombinant expression plasmid.Methods:1. Huh7.5.1cells were infected with2×106copies/ml HCV particles for32days. Intracellular HCV RNA and miR-122were analyzed by real-time PCR.2. Intracellular expressions of miR-122in Huh7.5.1cells infected with different levels of HCV (10copies,10copies,10copies and10copies) were assayed by real-time PCR.3. miR-122and HCV RNA expressions in Huh7.5.1cells transfected with0.5μg,1μg and2μg of the plasmid pEGFP-core or pEGFP were detected at48h posttransfection. Huh7.5.1cells transfected with1.5μg of plasmid pEGFP-core or pEGFP were harvested at24h,48h and72h posttransfection, and the relative expressions of miR-122were assayed by real-time PCR.Results:1. The level of miR-122increased at the early stage of infection. On the19th day after infection with HCV, miR-122expression level began to decrease and reached the minimum level of50%at day32post-infection. While the HCV RNA level increased rapidly during the infection.2. There was a～134%increase of miR-122expression with statistical significance in the105copies group; in contrast, miR-122was～33%significantly reduced in the108copies group compared to the control group (P<0.05).3. HCV core protein suppressed the expression of miR-122in a time-and dose-dependent manner and the susceptibility of Huh7.5.1cells to HCV (P<0.05or P<0.01). In contrast, there wasn’t an obvious change in the expression of miR-122and the susceptibility of Huh7.5.1cells to HCV in pEGFP group.Conclusion:Down-regulating miR-122expression by HCV core protein may give a new insight into the interaction between HCV and miR-122and chronic HCV infection.