Modulation of HBV Replication by the Immunoproteasome

描述（由申请人提供）：乙型肝炎病毒（HBV）在感染个体中引起自限性急性或慢性肝炎。全世界约有3.5亿人慢性感染乙肝病毒，每年导致100多万人死于肝硬化和肝细胞癌。该应用程序的长期目标是确定调节HBV复制和持久性的细胞机制。从受感染宿主清除HBV可能需要干扰素（IFN）诱导的对HBV复制的非细胞病变抑制，以及病毒特异性细胞毒性t淋巴细胞（CTL）杀死受感染的肝细胞。先前，已经证明IFN通过以蛋白酶体依赖的方式降低含HBV rna的衣壳的组装和/或稳定性来抑制HBV复制。蛋白酶体是一种大型多亚基蛋白酶，可降解细胞质和核蛋白，从而调节蛋白质稳定性并产生供MHC I类分子呈递的肽。因此，蛋白酶体和HBV之间的相互作用可能是病毒复制和感染进展为急性或慢性肝病的重要决定因素。因此，我们将检验IFN对蛋白酶体活性的调节对于HBV复制的非细胞病变抑制以及宿主对病毒的适应性免疫反应至关重要的假设。在HBV转基因小鼠和永生化肝细胞系中使用基于RNA干扰的方法，我们将确定IFN诱导的蛋白酶体催化（LMP2, LMP7, MECL-1）或调节（PA28）亚基是否介导IFN对HBV复制的抑制。我们还将利用缺乏这些亚基的人HLA-A2转基因小鼠，研究LMP2和LMP7对HBV核心、聚合酶和包膜蛋白的CTL反应的强度、特异性和亲切度的影响。这些研究可以更好地了解调节HBV复制并最终决定感染结果的宿主因素。

DESCRIPTION (provided by applicant): The hepatitis B virus (HBV) causes either self-limiting acute or chronic hepatitis in infected individuals. Approximately 350 million people are chronically infected with HBV worldwide, leading to over 1 million deaths per year from cirrhosis and hepatocellular carcinoma. The long-term goal of this application is to define the cellular mechanisms that modulate the replication and persistence of HBV. The clearance of HBV from an infected host likely requires both the non-cytopathic inhibition of HBV replication induced by interferon (IFN), as well as the killing of infected hepatocytes by virus-specific cytotoxic T-lymphocytes (CTL). Previously, it has been demonstrated that IFN inhibits HBV replication by reducing the assembly and/or stability of HBV RNA-containing capsids in a proteasome-dependent manner. The proteasome is a large multisubunit protease that degrades cytoplasmic and nuclear proteins, thereby regulating protein stability and generating peptides for presentation by MHC class I molecules. The interaction between the proteasome and HBV may therefore be an important determinant of viral replication and the progression of infection to either acute or chronic liver disease. Thus, we will examine the hypothesis that regulation of proteasome activity by IFN is critical for both the non-cytopathic inhibition of HBV replication, as well as the host adaptive immune response to the virus. Using RNA interference-based approaches in HBV transgenic mice and immortalized hepatocyte cell lines, we will determine if the IFN-inducible proteasome catalytic (LMP2, LMP7, MECL-1) or regulatory (PA28) subunits mediate the inhibition of HBV replication by IFN. We will also examine the influence of LMP2 and LMP7 on the magnitude, specificity, and avidity of the CTL response to the HBV core, polymerase, and envelope proteins using human HLA-A2 transgenic mice genetically deficient for these subunits. These studies may provide a better understanding of the host factors that modulate HBV replication and that ultimately determine the outcome of infection.