Viral and host determinants of Zika virus tissue tropism

项目摘要 寨卡病毒(ZIKV)是一种由蚊子传播的黄病毒，1947年最初在乌干达发现，几乎所有 它的病史一直与轻微的自限性疾病有关。在最近和正在进行的ZIKV期间，这种情况发生了变化 南太平洋和拉丁美洲的疫情，揭示了新的传播方式(即性传播 和子宫内)，以及意外的疾病表现(包括出生缺陷和格林-巴利 综合症)。这些严重的寨卡病毒感染表现都涉及病毒入侵组织，通常情况下 受到解剖屏障的保护，包括中枢神经系统、睾丸和胎儿 车厢。了解决定ZIKV组织嗜性的病毒和宿主因素对于 在新的寄主环境中评估新出现的ZIKV毒株的致病潜力。在这项提案中，我们 将使用一种新的ZIKV反向遗传学系统来实验测试这一假设 目前在拉丁美洲流行的ZIKV毒株具有更强的毒力。尤其是，我们将重点关注 病毒粒子包膜蛋白中的N-连接糖基化，因为这是公认的毒力决定因素 其他黄病毒，在当代ZIKV暴发毒株和历史毒株之间存在差异。自小说以来 组织嗜性可能有助于ZIKV感染的新表现，我们将研究干扰素的作用 Lambda(干扰素-λ)在维持ZIKV组织趋向性的屏障中的作用，包括血脑屏障、胎盘和 支持细胞屏障，正如先前西尼罗河病毒神经侵袭所显示的那样。我们将感染那些 缺乏干扰素-L受体，比较中枢神经系统、胎儿脑室、睾丸、 以及眼睛到没有特殊屏障保护的组织和野生型老鼠。相反，我们会 感染缺乏干扰素-ab受体的小鼠，这会产生高病毒载量和组织传播，用 重组干扰素-L蛋白的表达及其对寨卡病毒屏障的影响 入侵。干扰素-L蛋白已成功用于丙型肝炎的II期临床试验 病毒感染，这种方法将为治疗严重的ZIKV感染提供一种潜在的方法。总之，我们的 研究将揭示ZIKV组织嗜性的关键病毒和宿主决定因素，理解 在拉丁美洲本次暴发中观察到寨卡病毒感染的严重表现。

Project Summary Zika virus (ZIKV), a mosquito-borne flavivirus, was originally discovered in Uganda in 1947, and for nearly all of its history has been associated with mild self-limited illness. This changed during recent and ongoing ZIKV outbreaks in the South Pacific and Latin America, which have revealed new modes of transmission (i.e. sexual and in utero), as well as unexpected disease presentations (including birth defects and Guillain-Barré syndrome). These severe manifestations of ZIKV infection all involve the virus invading tissues that ordinarily are protected by anatomic barriers, including the central nervous system, the testes, and the fetal compartment. Understanding the viral and host factors that determine ZIKV tissue tropism is critical for evaluating the pathogenic potential of emerging ZIKV strains in new host environments. In this proposal, we will employ a new ZIKV reverse genetics system to experimentally test the hypothesis that genetic changes in the ZIKV strains currently circulating in Latin America confer enhanced virulence. In particular, we will focus on N-linked glycosylation in the virion envelope protein, as this is well-established as a virulence determinant in other flaviviruses and differs between contemporary outbreak strains of ZIKV and historical ones. Since novel tissue tropism may contribute to new manifestations of ZIKV infection, we will investigate the role of interferon lambda (IFN-λ) in maintaining barriers to ZIKV tissue tropism, including the blood-brain barrier, placenta, and sertoli cell barrier, as has been shown previously for West Nile virus neuroinvasion. We will infect mice that lack the IFN-L receptor and compare ZIKV viral loads in the central nervous system, fetal compartment, testes, and eyes to tissues that are not protected by specialized barriers and to wild-type mice. Conversely, we will infect mice that lack the IFN-ab receptor, which develop high viral loads and tissue dissemination, with recombinant IFN-L protein and determine whether this results in barrier tightening and restriction of ZIKV invasion. As IFN-L protein has been used successfully in phase II clinical trials as a therapy for hepatitis C virus infection, this approach would provide a potential method to treat severe ZIKV infection. Altogether, our studies will reveal key viral and host determinants of ZIKV tissue tropism, key aspects of understanding the severe manifestations of ZIKV infection observed in the current outbreak in Latin America.