Dynamics and immune control of norovirus infection in neonatal mice

项目概要/摘要 诺如病毒（NoV）是全球急性胃肠炎的主要原因，估计与6.85亿人有关。 案件每年。NoV感染所有年龄段的个体，但感染在5岁以下的儿童中最严重， 每年造成大约5万人死亡幼儿也会经历长时间的 高病毒载量的粪便脱落，在整个人群的传播中发挥关键作用。然而，在这方面， 导致NoV严重程度和脱落随年龄变化的宿主因素尚未明确。 鼠NoV（MNoV）被用作研究体内病毒发病机制的模型，但几乎所有的研究都是在动物模型中进行的。 在成年小鼠中进行。这项工作的首要目标是使用新生小鼠作为模型来了解 NoV在幼龄动物中的动力学和免疫控制。初步研究表明， 与成年小鼠相比，新生小鼠中持续MNoV感染的组织嗜性发生了改变。此外，先天 免疫应答是控制新生儿病毒感染的核心。新生的Stat 1-/-小鼠，它们缺乏一种 在一些实施方案中，MNoV是干扰素信号传导所必需的转录因子，脱落更高水平的MNoV并屈服于感染。这 致死性是幼年动物所特有的，因为成年Stat-/-小鼠通常在感染MNoV的持久株后存活。 该提议的总体假设是IFN应答限制新生儿中MNoV的复制和嗜性， 从而控制粪便脱落和致死率。我们将使用我们的新生儿MNoV模型来验证这一假设 感染在目标1中，我们将定义病毒复制和感染性病毒粒子脱落的动力学，并定义 MNoV在野生型和Stat 1-/-新生儿中的细胞嗜性。在目标2中，我们将描述时间，定位， 以及IFN应答是否控制病毒突变和/或肠外 传播。这些研究将有助于解释导致病毒发病机制变异的宿主因素， 持续脱落的年龄，并将代表着一个重大的进步，了解差异， 成人和儿童之间的肠道病毒动态。 这项工作将在圣路易斯的华盛顿大学进行，该大学提供了特殊的访问机会， 完成这些研究所需的资源和培训。使用尖端设施，如中心 细胞成像和DNA测序创新实验室，以及充足的培训机会， 校园内的核心设施，使这些实验在技术上成为可能。分子微生物学的支持 和微生物发病机制计划和导师从赞助商和其他教师在校园将确保 成功完成了所提出的研究。

Project Summary/Abstract Norovirus (NoV) is the leading global cause of acute gastroenteritis, associated with an estimated 685 million cases annually. NoV infects individuals of all ages but infection is most severe in children under the age of 5, causing approximately 50,000 deaths in this population each year. Young children also experience prolonged fecal shedding with high viral loads, playing a key role in transmission throughout the entire population. However, the host factors which contribute to variability in NoV severity and shedding by age are not well-defined. Murine NoV (MNoV) is used as a model to study viral pathogenesis in vivo, but almost all studies have been conducted in adult mice. The overarching objective of this work is to use neonatal mice as a model to understand the dynamics and immune control of NoV in young animals. Preliminary studies suggest that the cellular and tissue tropism of persistent MNoV infection is altered in neonatal mice compared to adult mice. Further, innate immune responses are central to controlling viral infection in neonates. Neonatal Stat1-/- mice, which lack a transcription factor necessary for interferon signaling, shed higher levels of MNoV and succumb to infection. This lethality is unique to young animals, as adult Stat-/- mice typically survive infection with persistent strains of MNoV. The overall hypothesis of this proposal is that IFN responses limit MNoV replication and tropism in neonates, thereby controlling fecal shedding and lethality. We will test this hypothesis using our neonatal model of MNoV infection. In Aim 1, we will define the kinetics of viral replication and shedding of infectious virions and define the cellular tropism of MNoV in wild-type and Stat1-/- neonates. In Aim 2, we will characterize the timing, localization, and function of individual IFN responses and whether IFN responses control viral mutation and/or extraintestinal dissemination. These studies will help explain host factors which contribute to variation in viral pathogenesis and persistent shedding by age and will represent a significant advancement into understanding the differences in enteric virus dynamics between adults and children. This work will take place at Washington University in St. Louis, which provides exceptional access to the resources and training necessary to complete these studies. Access to cutting-edge facilities such as the Center for Cellular Imaging and DNA Sequencing Innovation lab, as well as ample training opportunities available from on-campus core facilities, make these experiments technically possible. Support from the Molecular Microbiology and Microbial Pathogenesis program and mentorship from sponsors and other faculty on campus will ensure the successful completion of the proposed research.