Host and viral determinants of hepatitis C virus species tropism

项目摘要 丙型肝炎病毒（HCV）是美国肝癌和肝移植的主要原因之一。 虽然目前的治疗显示出相当大的希望，但世界各地的许多患者将无法从中受益。 由于成本和需要长期管理和监测，此外，治愈的患者 不能防止新的HCV感染。一种保护性疫苗将大大加强减少艾滋病的努力。 HCV对全球健康的影响。免疫活性动物模型将有助于开发一种 然而，这种努力受到HCV严格的种嗜性的阻碍，因为有效的HCV 感染仅限于人类和黑猩猩。本申请中提出的实验是 旨在研究HCV嗜性调节的基本机制，并基于我们的假设， HCV的种特异性嗜性至少部分受到HCV进入细胞的能力差异的影响， 宿主细胞并抑制不同物种的先天免疫反应。我们最近观察到雪貂 能够支持体内HCV感染，但比在人类和黑猩猩中观察到的水平弱得多。 我们试图了解是什么控制了HCV在入境和入境后的病毒嗜性， 探索雪貂中HCV感染的物种特异性阻断。我们的初步研究表明 紧密连接蛋白闭合蛋白（OCLN）的一种形式不能有效地作为HCV进入因子发挥作用。到 为了将雪貂OCLN活性的细胞决定因素定义为HCV进入因子，我们将绘制关键残基 在HCV进入过程中影响其作为进入因子的功能。我们还将选择丙型肝炎病毒中的突变， 基因组，将允许更有效地利用雪貂OCLN。此外，我们还发现， 先天性免疫反应也受到物种特异性因素的影响，因为我们已经发现HCV是 无法切割雪貂MAVS我们提出实验来检查主机和病毒的决定因素，影响 HCV切割雪貂MAVS，并确定先天免疫系统的抑制不足如何在 雪貂感染HCV影响病毒复制。通过识别物种特异性进入、复制和先天免疫 限制HCV感染广泛的物种，并定义这些块如何有助于HCV 病毒嗜性，我们可以设计出有效的HCV感染的方法，在一系列物种，以及提供洞察力 宿主-病原体相互作用如何影响一系列其他病毒的生命周期和宿主易感性 具有相似的复制和免疫逃避机制。

Project Summary Hepatitis C virus (HCV) is one of the leading causes of liver cancer and liver transplants in the United States. While current treatments show considerable promise, many patients worldwide will not benefit from these treatments due to cost and required long-term administration and monitoring. Furthermore, cured patients are not protected from new HCV infection. A protective vaccine would greatly augment the efforts to reduce the global health impact caused by HCV. An immunocompetent animal model would aid development of an effective HCV vaccine however; this effort is impeded by HCV's strict species-tropism, as efficient HCV infection is restricted to only humans and chimpanzees. The experiments proposed in this application are aimed at studying the basic mechanisms by which HCV tropism is regulated, and are based on our hypothesis that HCV species-specific tropism is influenced, at least in part, by differences in the capacity for HCV to enter host cells and suppress innate immune responses in disparate species. We recently observed that ferrets are able to support HCV infection in vivo, but at much weaker levels than observed in humans and chimpanzees. We seek to understand what controls viral tropism of HCV during both entry and post-entry events and will explore species-specific blocks to HCV infection in ferrets. Our preliminary studies identified that the ferret version of the tight junction protein occludin (OCLN) does not function efficiently as an HCV entry factor. To define the cellular determinants of ferret OCLN's activity as an HCV entry factor, we will map critical residues that influence its function as an entry factor during HCV entry. We will also select for mutations in the HCV genome that will allow more efficient use of ferret OCLN. Furthermore, we have found that HCV suppression of the innate immune response is also influenced by species-specific factors, as we have found that HCV is unable to cleave ferret MAVS. We propose experiments to examine host and viral determinants that influence HCV cleavage of ferret MAVS and determine how inadequate suppression of the innate immune system in ferrets by HCV influences viral replication. By identifying species-specific entry, replication and innate immunity restrictions to HCV infection across a wide range of species and defining how these blocks contribute to HCV viral tropism, we can devise methods for efficient HCV infection in a range of species as well as provide insight on how host-pathogen interactions impact the life cycles and host susceptibility for a range of other viruses with similar replication and immune evasion mechanisms.