The Antiviral Mechanism Of The Protein Inhibitors Against The Non-structure Protein2of Hepatitis C Virus

Hepatitis C virus (HCV) has infected approximately3%of world population,leading to chronic hepatitis, cirrhosis and even hepatocellular carcinoma. A protectivevaccine is not yet available and therapeutic options are still limited. Current standardtherapy, which is pegylated interferon-α combined with ribavirin, can not beguaranteed to cure all types of HCV patients, calls for a long course of treatment cycle,and induces many side effects. Therefore, there is an urgent need to develop moreeffective and better tolerated therapies for chronic hepatitis C.Non-structural protein2(NS2) serves as a vital role in the HCV life cycle. Itplays a role in the assembly and release parts of the HCV, and influences the HCVreplication via interaction with the host factors. So, NS2can be an attractive target forantiviral research.Aptamers are new kind of recognition molecules with good selectivity, highaffinity, easy modification, good stability and other advantages. Aptamers havenumerous obvious advantages over antibodies because of their high specificity to thetargets, tiny molecular weight, convenient synthesis and easy modification, lowimmunogenicity, and long-term stability. Researches found that it has wide prospectsto use the aptamers obtained via SELEX technology in the development of drugs.After getting three NS2-specific aptamers, we did research into the influences ofthese NS2-specific aptamers throughout the HCV life cycle and the correspondingantiviral way. First after cloning eukaryotic NS2protein segments, we initiallyconfirmed the aptamers’ recognition section via competition experiments in this paper.Then we further confirmed the interaction sites through adaptive mutation screening.After confirming the interaction sites, we further explored the specific NS2aptamers’antiviral mechanism. The data showed that: physical aptamers specifically bind to NS2proteins. The aptamars showed no apparent toxic effect to the cells. Aptamer NS2-3inhibits HCV replication in replicon cell lines and infectious cell lines; aptamer NS2-2was demonstrated to inhibit the infectious virus production without cytotoxicity invitro. NS2-2inhibits HCV infection primarily by binding to the N-terminal domain ofthe NS2protein, and disrupting the interaction between NS5A and NS2. I861T withinNS2is the major resistance mutation identified.Conclusion: NS2specific aptamers exerts antiviral activity mainly via binding tothe N-terminal binding protein NS2, with inhibiting the interaction between the NS2 and the NS5A protein. NS2specific aptamers with anti-HCV effect was the firstdiscovery ever reported. It is helpful to better understand the life cycle of the HCVvirus itself through doing Research into exact antiviral mechanism of the NS2specificaptamers. All together, these aptamers have great potential in the future HCV drugdevelopment and new combined therapeutic areas.