Host and viral determinants of hepatitis C virus species tropism

项目摘要 丙型肝炎病毒(丙型肝炎病毒)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前景，但世界各地的许多患者将不会从这些治疗中受益 治疗费用高，需要长期给药和监测。此外，治愈的患者是 没有保护自己免受新的丙型肝炎病毒感染。一种保护性疫苗将极大地加强减少 丙型肝炎病毒对全球健康的影响。具有免疫能力的动物模型将有助于发展 然而，有效的丙型肝炎病毒疫苗；这一努力受到丙型肝炎病毒严格的物种取向的阻碍，因为有效的丙型肝炎病毒 感染仅限于人类和黑猩猩。此应用程序中建议的实验包括 旨在研究调节丙型肝炎病毒嗜性的基本机制，并基于我们的假设 丙型肝炎病毒的物种特异性取向至少部分受到丙型肝炎病毒进入能力的差异的影响。 宿主细胞和抑制不同物种的先天免疫反应。我们最近观察到雪貂 能够支持体内的丙型肝炎病毒感染，但水平比在人类和黑猩猩中观察到的要弱得多。 我们试图了解在进入和进入后事件中是什么控制了丙型肝炎病毒的趋向性，并将 探索对雪貂感染丙型肝炎病毒的物种特异性阻断。我们的初步研究发现，雪貂 紧密连接蛋白阻断素(OCLN)的版本不能有效地作为丙型肝炎病毒的进入因子。至 将雪貂OCLN活性的细胞决定因素定义为丙型肝炎病毒进入因子，我们将绘制关键残基 这影响了它在丙型肝炎病毒进入过程中作为进入因子的作用。我们还将选择丙型肝炎病毒的突变 将允许更有效地利用雪貂OCLN的基因组。此外，我们还发现，丙型肝炎病毒抑制 先天免疫反应也受到物种特异性因素的影响，因为我们发现丙型肝炎病毒是 无法劈开雪貂小牛。我们建议进行实验，以检查影响宿主和病毒决定因素 丙型肝炎病毒裂解雪貂MAV和确定如何不充分地抑制先天性免疫系统在 丙型肝炎病毒感染的雪貂会影响病毒复制。通过识别特定物种的进入、复制和先天免疫 对多种物种的丙型肝炎病毒感染的限制，并确定这些阻断是如何导致丙型肝炎病毒的 病毒嗜性，我们可以设计出在一系列物种中有效感染丙型肝炎病毒的方法，并提供洞察力 关于宿主-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.