Apolipoprotein E but Not B Is Required for the Formation of Infectious Hepatitis C Virus Particles
Apolipoprotein E but Not B Is Required for the Formation of Infectious Hepatitis C Virus Particles
复制标题
DOI：
10.1128/jvi.01476-09
复制
发表时间：
2009-12-15
影响因子：
5.4
通讯作者：
Luo, Guangxiang
中科院分区：
文献类型：
--
作者：
Jiang, Jieyun;Luo, Guangxiang
我们以前的研究发现，丙型肝炎病毒（HCV）颗粒富含载脂蛋白E（apoE），而apoE是HCV感染和产生所必需的。然而，其他人的研究表明，微粒体转移蛋白（MTP）和载脂蛋白B对HCV的产生都很重要。为了确定apoB和apoE在HCV生命周期中的作用，我们开发了一种单周期HCV生长试验，以确定HCV组装与apoB和apoE表达的相关性，以及MTP抑制剂对HCV颗粒形成的影响。小干扰RNA（siRNA）介导的apoE表达的敲低显着抑制HCV颗粒的形成。然而，异位表达的apoE可以恢复由siRNA介导的内源性apoE表达的敲低所造成的HCV产生的缺陷。与此相反，载脂蛋白B特异性抗体和siRNA对HCV感染性和产生分别没有显著影响，表明载脂蛋白B在HCV生命周期中不起重要作用。此外，两种MTP抑制剂CP-346086和BMS-2101038有效地阻断了含载脂蛋白B的脂蛋白的分泌，但不影响HCV的产生，除非抑制载脂蛋白E的表达和分泌。然而，在较高浓度下，MTP抑制剂阻断apoE表达和分泌，从而抑制HCV颗粒的形成。此外，载脂蛋白E被认为是敏感的胰蛋白酶消化和相互作用与NS 5A在纯化的HCV颗粒和HCV感染的细胞，如所示的免疫共沉淀。总的来说，这些研究结果表明，apoE，而不是apoB所需的HCV组装，可能通过与NS 5A的特异性相互作用。
Our previous studies have found that hepatitis C virus (HCV) particles are enriched in apolipoprotein E (apoE) and that apoE is required for HCV infectivity and production. Studies by others, however, suggested that both microsomal transfer protein (MTP) and apoB are important for HCV production. To define the roles of apoB and apoE in the HCV life cycle, we developed a single-cycle HCV growth assay to determine the correlation of HCV assembly with apoB and apoE expression, as well as the influence of MTP inhibitors on the formation of HCV particles. The small interfering RNA (siRNA)-mediated knockdown of apoE expression remarkably suppressed the formation of HCV particles. However, apoE expressed ectopically could restore the defect of HCV production posed by the siRNA-mediated knockdown of endogenous apoE expression. In contrast, apoB-specific antibodies and siRNAs had no significant effect on HCV infectivity and production, respectively, suggesting that apoB does not play a significant role in the HCV life cycle. Additionally, two MTP inhibitors, CP-346086 and BMS-2101038, efficiently blocked secretion of apoB-containing lipoproteins but did not affect HCV production unless apoE expression and secretion were inhibited. At higher concentrations, however, MTP inhibitors blocked apoE expression and secretion and consequently suppressed the formation of HCV particles. Furthermore, apoE was found to be sensitive to trypsin digestion and to interact with NS5A in purified HCV particles and HCV-infected cells, as demonstrated by coimmunoprecipitation. Collectively, these findings demonstrate that apoE but not apoB is required for HCV assembly, probably via a specific interaction with NS5A.