National Institute for Infectious Diseases L Spallanzani IRCCS, Rome, Italy.
Gut. 2011 Mar;60(3):378-86. doi: 10.1136/gut.2010.211292. Epub 2010 Oct 12.
BACKGROUND/AIMS: The life cycle of hepatitis C virus (HCV) is intimately linked to the lipid metabolism of the host. In particular, HCV exploits the metabolic machinery of the lipoproteins in several steps of its life cycle such as circulation in the bloodstream, cell attachment and entry, assembly and release of viral particles. However, the details of how HCV interacts with and influences the metabolism of the host lipoproteins are not well understood. A study was undertaken to investigate whether HCV directly affects the protein composition of host circulating lipoproteins.
A proteomic analysis of circulating very low-, low- and high-density lipoproteins (VLDL, LDL and HDL), isolated from either in-treatment naïve HCV-infected patients or healthy donors (HD), was performed using two-dimensional gel electrophoresis and tandem mass spectrometry (MALDI-TOF/TOF). The results obtained were further investigated using in vitro models of HCV infection and replication.
A decreased level of apolipoprotein A-I (apoA-I) was found in the LDL fractions of HCV-infected patients. This result was confirmed by western blot and ELISA analysis. HCV cellular models (JFH1 HCV cell culture system (HCVcc) and HCV subgenomic replicons) showed that the decreased apoA-I/LDL association originates from hepatic biogenesis rather than lipoprotein catabolism occurring in the circulation, and is not due to a downregulation of the apoA-I protein concentration. The sole non-structural viral proteins were sufficient to impair the apoA-I/LDL association. Functional evidence was obtained for involvement of apoA-I in the viral life cycle such as RNA replication and virion production. The specific siRNA-mediated downregulation of apoA-I led to a reduction in both HCV RNA and viral particle levels in culture.
This study shows that HCV induces lipoprotein structural modification and that its replication and production are linked to the host lipoprotein metabolism, suggesting apoA-I as a new possible target for antiviral therapy.
背景/目的：丙型肝炎病毒（HCV）的生命周期与宿主的脂质代谢密切相关。特别是，HCV 在其生命周期的几个步骤中利用脂蛋白的代谢机制，例如在血液中循环、细胞附着和进入、病毒颗粒的组装和释放。然而，HCV 如何与宿主脂蛋白相互作用并影响其代谢的细节尚不清楚。进行了一项研究，以调查 HCV 是否直接影响宿主循环脂蛋白的蛋白质组成。
使用二维凝胶电泳和串联质谱（MALDI-TOF/TOF）对来自治疗中的 HCV 感染患者或健康供体（HD）的循环极低密度脂蛋白（VLDL）、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）进行了脂蛋白的蛋白质组学分析。使用 HCV 感染和复制的体外模型进一步研究了所得结果。
发现 HCV 感染患者的 LDL 部分中的载脂蛋白 A-I（apoA-I）水平降低。这一结果通过 Western blot 和 ELISA 分析得到了证实。HCV 细胞模型（JFH1 HCV 细胞培养系统（HCVcc）和 HCV 亚基因组复制子）表明，apoA-I/LDL 结合减少源自于肝脏生物发生，而不是发生在循环中的脂蛋白代谢，并且不是由于 apoA-I 蛋白浓度的下调引起的。仅非结构病毒蛋白就足以损害 apoA-I/LDL 结合。获得了 apoA-I 参与病毒生命周期的功能证据，例如 RNA 复制和病毒颗粒产生。apoA-I 的特异性 siRNA 介导下调导致培养物中 HCV RNA 和病毒颗粒水平降低。
这项研究表明 HCV 诱导脂蛋白结构修饰，其复制和产生与宿主脂蛋白代谢有关，提示 apoA-I 可能是一种新的抗病毒治疗靶标。
