MxA’s Effect On HCV Replication And The Type Ⅰ Interferon Signaling Pathway

Backgroud:Type I interferons(IFNs)are a family of primordial cytokines that respond to various pathogen infections including Hepatitis C virus(HCV).Type I IFNs signal through Jak/STAT pathway leading to the production of a few hundred interferon stimulated genes(ISGs).HCV is the most common cause of hepatitis,liver cirrhosis,even liver cancer etiology,although the treatment strategy based on interferon can receive a good sustained virological response(SVR),but there are still some patients resistant to interferon.The results from our previous researches shows that partial ISGs can inhibit viral replication and promote IFN antiviral activity,while part of the ISGs can promote viral replication and inhibition of IFN antiviral activity.Aim:To determine whether MxA plays an antiviral role in HCV replication and the antiviral activity of IFNa,and explore the mechanisms.Material&Method:J6/JFH1 HCV culture system was used to determine the role of MxA in HCV replication and the anti-HCV activity of IFNa.Plasmid encoding MxA was cloned into pcDNA3.1-3×tag vector and MxA’s expression was confirmed both at mRNA(RT-PCR)and protein(WB)levels.The production of IFNα and IFNβ was quantified by RT-PCR from cell lysate and by ELISA kit from culture medium following MxA over-expression in Huh7.5.1 cells.The activation status of Jak/STAT signaling pathway was examined at　three levels:p-STAT1(WB),ISRE activity(dual luciferase reporter gene assay)and levels of ISGs expression(RT-qPCR).Results:In Huh7.5.1,the over-expression of MxA decreased JFH-1 expression with or without IFNa,indicating that MxA inhibited HCV replication and potentiated the IFNa-mediated anti-HCV activity.MxA stimulated the production of IFNa and IFNβ,with the upregulation of some important genes in I-IFN signaling pathway.At the same time,MxA enhanced IFNa-induced activation of Jak-STAT signaling pathway(p-STAT1 level,ISRE activity and expression levels of ISGs).Conclusion:MxA activates the Jak/STAT signaling pathway by promoting the production of IFNa and IFN(3,which can inhibit HCV replication and promote the antiviral activity of IFNa.