The Role of Transferrin Receptor 1 in Hepatitis C virus Entry

描述（由申请人提供）：丙型肝炎病毒（HCV）感染全球超过1.7亿人，引起急性和慢性肝炎以及肝细胞癌。由于没有疫苗可用于预防HCV感染，并且只有一部分慢性感染患者对目前的治疗方案有反应，因此迫切需要新的有效HCV抗病毒药物。自1989年发现以来，阻碍HCV研究的一个主要障碍是缺乏强大的细胞培养和小动物感染模型。虽然在过去的5年中，随着第一个稳健的体外HCV感染系统的开发，已经取得了显着的体外进展，但仍然需要开发用于病理学和免疫学研究的稳健且广泛可用的小动物模型。HCV进入不仅代表了药物发现的一个有希望的多方面的机会，但我们还没有确定所有的因素足以HCV感染，包括一个（S），决定了有限的肝脏和/或种属嗜性的感染性HCV进入。虽然最近发现人OCLN作为HCVpp进入小鼠细胞所必需的因子似乎使我们更接近于理解HCV物种嗜性，但迄今为止尚未实现非人细胞的真实HCVpp感染，这表明仍存在特异于HCVpp的其他进入因子。我们的长期目标是了解介导HCV进入的细胞和病毒因子，以确定新的分子靶点进行治疗干预，并促进急需的HCV感染的小动物模型的开发。因此，本R21申请的目的是阐明新鉴定的推定HCV进入因子的作用。具体来说，我们假设细胞转铁蛋白受体1（TfR 1）是一个HCV进入受体，它可能是负责HCV进入的限制性向性。这一假设是基于已发表的先例，表明TfR 1作为其他病毒的种属特异性受体发挥作用，我们的初步数据表明TfR 1是HCV进入所必需的。因此，我们将追求以下两个具体目标：1）通过确定TfR 1何时在HCV进入过程中起作用以及该相互作用是否涉及TfR 1与HCV的直接结合来表征TfR 1如何以及何时参与HCV进入，以及2）通过表征一组细胞以确定TfR 1表达是否赋予HCV对非肝或非肝细胞的耐受性来确定TfR 1是否是HCV嗜性的决定因素，人体细胞综上所述，这些信息将奠定基础，使一个更详细和具体集中的R 01应用程序，旨在彻底了解HCV TfR 1依赖的进入和/或发展的感染性HCV小鼠模型。

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) infects more than 170 million people worldwide, causing acute and chronic hepatitis and hepatocellular carcinoma. With no vaccine available to protect against HCV infection and only a subset of chronically infected patients responding to current treatment options, there is an immediate need for new effective HCV antivirals. Since its discovery in 1989, a major obstacle impeding HCV research has been the lack of robust cell culture and small animal infection models. While significant in vitro advancement has been made in the last 5 years with the development of the first robust in vitro HCV infection system, the development of a robust and widely available small animal model for pathology and immunology studies is still needed. HCV entry not only represents a promising multi-faceted opportunity for drug discovery, but we have yet to identify all the factors sufficient for HCV infection including the one(s) that dictate the restricted liver and/or species tropism of infectious HCV entry. While the recent discovery of human OCLN as a factor necessary for HCVpp entry into mouse cells appears to have brought us one step closer to understanding HCV species tropism, to date authentic HCVcc infection of non-human cells has not been achieved suggesting that other entry factors, specific for HCVcc, still exist. Our long term goal is to understand the cellular and viral factors that mediate HCVcc entry in order to identify novel molecular targets for therapeutic intervention and facilitate the much needed development of small animal models of HCV infection. As such, the objective of this R21 application is to elucidate the role of a newly identified putative HCV entry factor. Specifically, we hypothesize that the cellular transferrin receptor 1 (TfR1) is an HCV entry receptor and that it may be responsible for the restricted tropism of HCV entry. This hypothesis is based on published precedents demonstrating that TfR1 functions as a species specific receptor for other viruses and our preliminary data which demonstrate that TfR1 is required for HCV entry. Hence, we will pursue the following two specific aims: 1) To characterize how and when TfR1 participates in HCV entry by determining when TfR1 acts in the HCV entry process and if that interaction involves direct TfR1 binding to HCV and 2) To determine whether TfR1 is a determinant of HCV tropism by characterizing a panel of cells to determine if TfR1 expression confers HCVcc permissiveness to non-hepatic or non-human cells. Taken together, this information will lay the groundwork that will enable a more detailed and specifically focused R01 application aimed at thoroughly understanding HCV TfR1-dependent entry and/or the development of an infectious HCV mouse model.