Identification of host factors required by the tick-borne Powassan virus

项目总结 黄病毒在世界范围内造成严重的发病率和死亡率。病毒的突然出现和传播 例如寨卡病毒说明了我们的脆弱性，并强调需要做好准备，以应对相关的新出现 病毒。除了蚊媒的黄病毒外，扁虱传播的黄病毒的成员构成了越来越多的全球 我们缺乏有效的抗病毒药物的威胁。 鲍瓦桑病毒(Powassan Virus，POWV)是一种通过受感染的硬蜱叮咬传播的新型病毒。这个 POWV在人类中的血清阳性率大多未知，因为感染通常是无症状的。然而， 有症状的POWV感染可能发展为严重的、有时是致命的脑部疾病，并导致死亡 存活率约为10%的患者通常会出现长期的神经症状。严重者 感染POWV和其他壁虱传播的黄病毒的临床后果以及缺乏特异性 治疗突显出迫切需要更好地了解这些病毒在它们的扁虱和哺乳动物宿主中的情况。 以便开发预防性和治疗性的治疗方法。 该项目的目标是确定POWV所需的、也可能影响广泛范围的宿主因素 现有的和新出现的黄病毒。这些宿主蛋白可能是抗病毒的合适靶点。 干预，我们假设，由于它们的抑制而损害病毒复制可能允许先天和 适应性免疫以控制感染。此外，我们建议比较一组黄病毒，包括 POWV，以及它们对脊椎动物和无脊椎动物细胞中已识别的宿主因子的要求。我们相信 这些方法将使我们能够优先考虑未来药物开发研究的候选基因。 拟议的研究将利用CRISPR/Cas9筛选技术来敲除 人类基因组，目的是识别促进POWV感染的宿主因素。我们将使用类似的 以有针对性的排列形式评估各种人和扁虱细胞系中已识别的宿主因素 在感染不同的黄病毒期间。 我们预计，这项工作将扩大我们对扁虱和蚊媒黄病毒的了解， 特别是在临床表型(脑炎与出血性疾病)和对宿主的共同需求方面 各种因素。此外，它还将有助于确定哪些基因控制寄主物种和组织嗜性。共同努力，这项工作 将为黄病毒生物学的许多方面提供丰富的新见解。

PROJECT SUMMARY Flaviviruses cause significant morbidity and mortality worldwide. The sudden emergence and spread of viruses such as Zika illustrate our vulnerability and emphasize the need for preparedness against related emerging viruses. In addition to mosquito-borne flaviviruses, members of tick-borne flaviviruses pose an increasing global threat for which we lack effective antivirals. Powassan virus (POWV) is an emerging virus transmitted by the bite of infected Ixodes ticks. The seroprevalence of POWV in humans is mostly unknown as infections may often be asymptomatic. However, symptomatic POWV infections may progress in to severe and sometimes fatal encephalic disease with mortality rates of ~10% and surviving patients often suffer from debilitating long-term neurologic symptoms. The severe clinical consequences of infections with POWV and other tick-borne flaviviruses and the lack of specific treatments highlight an urgent need for a better understanding of these viruses in their tick and mammalian hosts so that preventative and therapeutic treatments can be developed. The goal of this project is to identify host factors required by POWV that may also impact a wide range of existing and emerging flaviviruses. These host proteins may represent suitable targets for antiviral interventions, and we hypothesize that impaired virus replication due to their inhibition may allow innate and adaptive immunity to control the infection. Further, we propose to compare a panel of flaviviruses, including POWV, and their requirements for the identified host factors in both vertebrate and invertebrate cells. We believe these approaches will allow us to prioritize candidate genes for future drug development studies. The proposed studies will utilize CRISPR/Cas9 screening technology to knock out every gene in the human genome with the goal of identifying host factors that facilitate POWV infection. We will use a similar approach in a targeted, arrayed format to evaluate the identified host factors in various human and tick cell lines during infection with diverse flaviviruses. We expect that this work will broaden our understanding of tick- and mosquito-borne flaviviruses, specifically in terms of clinical phenotype (encephalitic vs hemorrhagic disease) and the shared need for host factors. In addition, it will help to define which genes govern host species and tissue tropism. Together, this work will provide a wealth of new insights into many aspects of flavivirus biology.