Pathogenesis of HCV in a Novel Mouse Model

描述(申请人提供)：该项目扩展了我们在研究人类传染病和相关活体模型治疗方面的长期兴趣。由于共同的传播途径，艾滋病毒(人类免疫缺陷病毒)和丙型肝炎病毒(丙型肝炎病毒)双重感染非常普遍。在最近的一些流行病学研究中，HIV-1合并感染与丙型肝炎病毒/乙肝病毒感染患者的肝病进展加速相关。迫切需要一种用于研究丙型肝炎病毒/艾滋病免疫发病机制的小动物模型。目前所有的小鼠模型都只允许在缺乏功能免疫系统的情况下复制丙型肝炎病毒。这些模型对于研究宿主免疫反应、它们在丙型肝炎病毒致病机制中的作用以及潜在的免疫治疗方法都没有用处。Rag2-GammaC双基因敲除(DKO)小鼠缺乏T/B和NK细胞，并允许利用人HSC(DKO-Hu HSC)发展出具有功能的人类免疫系统。正常人T、B细胞和树突状细胞存在于胸腺、脾、外周血(PB)、肝脏和淋巴结(LN)等淋巴组织。我们还发现DKO-HU-HSC小鼠支持HIV-1感染，并在外周血/血浆中出现高病毒血症。人类CD4+T细胞被HIV-1以剂量依赖的方式逐渐耗尽。此外，在感染HSC-DKO的小鼠中，HIV-1感染持续了20周，淋巴组织中有HIV-1感染。此外，HIV-1或EBV感染会诱导人类免疫反应。最后，在人胎肝来源的肝细胞前体细胞与CD34+HSC细胞共移植的DKO小鼠(DKO-Hu HSC/Hep小鼠)中，人肝细胞与人免疫系统共移植。 该项目的长期目标是建立一个相关的小鼠模型来研究丙型肝炎病毒的感染和免疫发病机制，并测试基于免疫的新疗法来克服免疫耐受、炎症、纤维化和肝细胞癌。我们将首先建立DKO-Hu HSC/HEP模型，用于研究丙型肝炎病毒的感染和致病机制。我们将在模型中研究体内没有或存在HIV-1混合感染的情况下丙型肝炎病毒的复制和发病机制。我还建议通过选择性地消耗小鼠肝细胞和促进人肝细胞在DKO-Hu HSC/Hep小鼠中促进人肝细胞在DKO-Hu HSC/Hep小鼠中的植入来增加人肝细胞在DKO-Hu HSC/Hep小鼠中的植入。这些研究将为未来的研究奠定基础，并阐明控制丙型肝炎病毒疾病的新治疗策略。该模型还将用于测试新的抗丙型肝炎病毒(肝细胞癌)疗法。 项目简介：该项目将为研究人类肝细胞发育和丙型肝炎病毒感染及发病机制建立一种新的动物模型。我们将在体内没有或存在完整的人类免疫系统的情况下，在模型中研究丙型肝炎病毒的复制和发病机制。这些研究将为未来的研究奠定基础，并阐明控制丙型肝炎病毒疾病的新治疗策略。

DESCRIPTION (provided by applicant): This project extends our long-standing interests in studying human infectious diseases and therapy in relevant in vivo models. HIV (human immunodeficiency virus) and HCV (hepatitis C virus) dual infection is highly prevalent as a result of shared transmission routes. In a number of recent epidemiological studies, HIV-1 co-infection has been correlated with accelerated liver disease progression in HCV/HBV infected patients. A small animal model for studying HCV/HIV immuno-pathogenesis is urgently needed. All current mouse models allow only HCV replication in the absence of a functional immune system. Those models are not useful to study host immune responses, their contributions to HCV pathogenesis and potential immunotherapeutic approaches. The Rag2-gammaC double knockout (DKO) mouse lacks T/B and NK cells, and allows development of a functional human immune system with human HSC (DKO-hu HSC). Normal human T, B, and dendritic cells are present in lymphoid tissues such as thymus, spleen, peripheral blood (PB), liver and lymph nodes (LN). We also show that DKO-hu-HSC mice support HIV-1 infection with high viremia in the PB/plasma. Human CD4+ T cells are gradually depleted by HIV-1 in a dose-dependent manner. In addition, HIV-1 infection persisted in infected HSC-DKO mice for >20 weeks, with infectious HIV-1 in lymphoid tissues. Furthermore, HIV-1 or EBV infection induces human immune responses. Lastly, human hepatocytes are also co-engrafted with human immune system in the DKO mouse co-transplanted with human fetal liver derived hepatocyte progenitor cells with CD34+ HSC cells (DKO-hu HSC/Hep mouse). The long-term goals of this project are to establish a relevant mouse model to study the infection and immuno- pathogenesis of HCV, and to test novel immune-based therapeutics to overcome immune tolerance, inflammation, fibrosis and HCC. We will first establish the DKO-hu HSC/Hep model for studying HCV infection and pathogenesis. We will investigate HCV replication and pathogenesis in the absence or presence of HIV-1 co-infection in vivo in the model. I also propose to increase human hepatocyte engraftment in the DKO-hu HSC/Hep mouse by selectively depleting murine hepatocytes and promoting human hepatocytes in the DKO- hu HSC/Hep mouse. These studies will establish the foundation for future study and shed light on novel therapeutic strategies for controlling HCV diseases. This model will also be useful to test novel anti-HCV (HCC) therapeutics. Project Narrative: This project will establish a novel animal model for studying human hepatocyte development and HCV infection and pathogenesis. We will investigate HCV replication and pathogenesis in the absence or presence of an intact human immune system in vivo in the model. These studies will establish the foundation for future study and shed light on novel therapeutic strategies for controlling HCV diseases.