Interferon To Adjust The Mirna Expression Spectrum And Its Mechanism Of Anti Hcv Research

Hepatitis C virus (HCV) is the leading cause of Hepatitis C, cirrhosis, hepatocellular carcinoma representing a major public health problem with more than170million cases worldwide.Interferon-a (IFN-a) in combination with ribavirin is the standard therapeutic regimen to treat chronic HCV infection in most countries. However, it leads to viral eradication in about50%of treated patients, and is associated with significant adverse effects. Interleukin-28B (IL-28B) genetic variation has been recently reported as a potent predictor of HCV response to interferon (IFN) therapy.Despite the short identification history of type IIIIFNs, the characterizing of IL-28Bhave considerably contributed to our understanding of the role of interferon, especially in viral infection research.In the current study, the anti-HCV activity, induction of IFN-stimulated genes (ISGs), receptor usage and cellular responsiveness of recombinant human IL-28B (rhIL-28B)were characterized.Using the Jcl-luciferase HCVcc system, we identified that rhIL-28B inhibited HCV propagation in Huh7.5.1cells with an IC50of0.15ng/ml. The combination of rhIL-28B and ribavirin synergistically inhibited HCV production in cell culture. Treatment of hepatoma cells with rhIL-28B resulted in the phosphorylation of STAT1within1hour and expression of ISGs within24hours. The HCV inhibitory effects of rhIL-28B were antagonized by the antibody neutralization of receptors IL-10R2and IL-28R1. Importantly, compared with the broad-spectrum activity of IFNa, we demonstrated restricted cell-type responsiveness of rhIL-28B in liver, lung,colon and prostate cells. IL-28B, with potent in vitro antiviral activity and restricted cell tropism,has promising a novel antiviral candidate for improving the treatment of HCV-infected patients.IFNs are integral to innate mammalian antiviral immunity. IFNs bind to their receptors on the cell membrane, activate the JAK/STAT signaling pathway and induce ISGs. ISGs are believed to contribute to antiviral effects. However, emerging evidence suggests that microRNAs (miRNAs), a class of non-coding small RNAs, are involved in the control of viral infection. There are rare researches about type Ⅰ and Ⅲ IFN regulating miRNAs expression and miRNAs involving in antiviral activity of IFNs.Here, we systematically profiled the hepatocyte expression of a set of750miRNAs in response to IFN-a and IL-28B treatments.160miRNAs found to be differentially expressed in response to IFN-a or IL-28B treatment.The anti-HCV activity of differentially expressed miRNAs was evaluated in vitro. Notably, the overexpression of let-7b significantly inhibited HCV infection in dose-and time-dependent manners. Deletion of the wild-type seed region of let-7b abolished its antiviral activity. When used in combination with the known HCV inhibitors, let-7b overexpression produced additive effects on HCV inhibition.Using HCVcc, HCVpp, HCV replicon and HCV IRES directed-luciferase system, we demonstrated that let-7b had a significant anti-HCV effect by inhibiting HCV replication and translation.The inhibition of viral infection by miRNA might occur either via the targeting of viral sequences or by the regulation of host genes that participate in the viral life cycle. In addition to the direct targeting of HCV genome by let-7b, we also showed that the host factor insulin-like growth factor2mRNA-binding protein1(IGF2BP1) is a target of let-7b. Let-7family miRNAs were able to inhibit HCV and to suppress IGF2BP1expression.In particular,IGF2BP1was required for HCV replication, and its expression was down-regulated by IFN-α and IL-28B. We showed that the inhibition of let-7b attenuated the anti-HCV effects of IFN-α and IL-28B. Let-7b contributes to the anti-viral activity of IFN.In conclusion,we characterized the anti-HCV activity, induction of IFN-stimulated genes (ISGs), receptor usage and cellular responsiveness of IL-28B,and provides a novel anti-HCV agent.Here, we systematically profiled the hepatocyte expression of a set of750miRNAs in response to type Ⅰ and Ⅲ IFNs treatments. The anti-HCV activity of differentially expressed miRNAs was evaluated using HCVccin vitro. An example of a host miRNA, let-7b, regulated by types Ⅰ and Ⅲ IFNs and inhibiting HCV replication and viral protein translation by targeting both viral and host targets was provided. These results highlight the important roles of let-7band type Ⅲ IFNsin the host antiviral immune response, and provide novel candidates for anti-HCV therapy.