Viperin蛋白可通过影响非结构蛋白与脂筏的关联抑制丙型肝炎病毒复制

Viperin protein inhibits hepatitis C virus replication partially through disturbing the association of nonstructural proteins with lipid rafts

目前,对丙型肝炎病毒(HCV)感染患者主要采用以Ⅰ型干扰素为主的治疗方案,但干扰素抑制病毒的具体机制仍然不详。本研究通过实时聚合酶链反应(PCR)检测HCV的RNA水平,蛋白免疫印迹法检测HCV非结构蛋白的表达,以及膜飘浮实验检测非结构蛋白与脂筏的关联性,探讨干扰素诱导蛋白Viperin抑制HCV复制的机制。结果显示,在体外HCV亚基因复制子及感染细胞模型中过量表达Viperin可显著降低细胞内HCV非结构蛋白的表达及RNA的水平。膜漂浮实验发现,过量表达的Viperin可通过干扰HCV非结构蛋白NS3、NS5A与细胞内脂筏膜的关联,使其对非离子去污剂敏感。进一步研究发现,与脂筏膜结构组成相关的法尼基合成酶(FPPS)可通过与Viperin相互作用,部分反转Viperin的抗HCV复制效应。以上结果提出一种新的干扰素抗HCV机制,即干扰素诱导蛋白Viperin可通过影响非结构蛋白与脂筏的关联,干扰HCV复制复合体的稳定性,从而抑制HCV复制。

Infection with hepatitis C virus （HCV） is currently treated with interferon-α （IFN-α）, but the molecular mechanism by which IFN inhibits HCV replication still remains elusive. Therefore, in this study, we attempted to elucidate the possible mechanism for the IFN-inducible protein, Viperin, against HCV. Over-expression of Viperin could significantly down-regulate intracellular levels of HCV protein and RNA in both the replicon and HCVcc systems. Membrane flotation analysis indicated that expression of Viperin could interfere with the association of HCV NS3 and NSSA with the lipid raft, resulting in increased sensitivity of these two proteins to the treatment of non-ionic detergent. Furthermore, Viperin was able to interact with FPPS and co-transfection of Viperin with FPPS could partially reverse the anti-HCV effects of Viperin in replicon cells. The above results indicate a possible novel mechanism of IFN-induced antiviral activity, that is, over-expression of Viperin can interfere with the microdomain of intracellular lipid raft and, therefore, further disrupt the stability of viral replicase complex to inhibit its functions.