Regulation of Rotavirus Replication, Virulence, and Host Range Restriction by the Innate Immune System

先天免疫系统对轮状病毒复制、毒力和宿主范围限制的调节

基本信息

批准号：
9308428
负责人：
Harry Bernard Greenberg
金额：
$ 22.06万
依托单位：
PALO ALTO VETERANS INSTIT FOR RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-02-15 至 2022-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9308428
关键词：
Adaptor Signaling Protein Address Animals Antiviral Agents Area Biological Assay Biological Models Biology Bystander Effect Cells Chemicals Child Communicable Diseases Complex Cryoelectron Microscopy Cullin Proteins Data Down-Regulation Enteral Enzymes Epithelial Cells Gastroenteritis Hematopoietic Human IRF3 gene Immune Evasion Impairment In Vitro Innate Immune Response Innate Immune System Interferon Receptor Interferons Intestines Mediating Mitochondria Mitochondrial Proteins Molecular Mucosal Immunity Mus Mutagenesis Natural Immunity Pathogenesis Pattern Phase Phosphorylation Prevention Production Protein Inhibition Proteins RNA Caps Receptor Gene Receptor Inhibition Regulation Research Role Rotavirus Rotavirus Infections Rotavirus NSP1 protein SH2D3A gene STAT1 gene Signal Transduction Signaling Protein Small Interfering RNA System TBK1 gene Ubiquitination Vaccines Viral Viral Proteins Virulence Virulent Virus beta-Transducin Repeat-Containing Proteins cullin-3 enteric pathogen gastrointestinal in vivo in vivo Model killings knock-down non-Native pathogen protein degradation receptor response sensor success ubiquitin-protein ligase

项目摘要

PROJECT SUMMARY/ABSTRACT Rotaviruses (RVs) are highly infectious viruses of great importance because they are the most common cause of severe gastroenteritis in young children. We will address three fundamental topics in rotavirology (RV) that will expand our understanding of the molecular mechanisms regulating RV innate immune evasion. 1. Determine the structural basis and in vivo activity of NSP1-mediated β-TrCP degradation. Despite the RV NSP1 protein's well-documented ability to induce IRF3 and/or β-TrCP degradation, the mechanisms regulating this degradation are unknown. Human RV NSP1s specifically target β-TrCP. We have recently identified an unexpected role of the host Cullin-E3 ligase complex in NSP1's degradative functions. In this aim we will dissect how NSP1 is able to hijack the host Cullin-E3 ligase complex, induce β- TrCP degradation, block NF-κB activation and thereby promote homologous RV replication. 2. Identify the molecular mechanisms underlying MAVS degradation by VP3 in a strain- and host- specific fashion both in vitro and in vivo. We previously showed that ssRNA byproducts from RV infection are potent activators of cytosolic sensors RIG-I and MDA5, both of which converge on mitochondrial antiviral signaling protein (MAVS) to relay innate signaling and induce IFN expression. Unexpected preliminary findings suggest that MAVS is targeted for proteasomal degradation by the RV VP3 protein in a host range restricted (HRR) manner. Here we will explore the complex interplay between VP3 and MAVS from different RV species at a mechanistic level and evaluate the importance of VP3-mediated MAVS degradation in promoting RV replication in vitro and in vivo. 3. Identify the mechanism of RV NSP1-mediated inhibition of STAT1 activation and the intestinal cell origin of the IFN responses to RV infection. Despite the ability to efficiently suppress the induction of type I IFN in intestinal epithelial cells (IECs), homologous RV infection still induces substantial levels of type I and III IFNs in the gut. This IFN production suggests that RVs must be able to subvert IFN-mediated antiviral amplification as well as blocking IFN induction. RV NSP1 efficiently inhibits IFN-mediated STAT1 phosphorylation. New findings indicate RV blocks STAT1 activation by depleting multiple IFN receptors, likely by NSP1-directed degradation. RVs can also block IFN-directed STAT1 activation in uninfected cells in vitro. Whether this effect also occurs in vivo is unknown. We propose to identify the hematopoietic cell and IEC origins of type I and III IFNs elicited by RV infection. We will also examine the mechanistic determinants of RV-mediated IFN receptor degradation and inhibition of STAT1 activation and determine if differences in these functions contribute to RV HRR.

项目概要/摘要轮状病毒 (RV) 是一种具有高度传染性的病毒，非常重要，因为它们是最常见的病毒我们将讨论轮状病毒学的三个基本主题。 (RV)，这将扩大我们对调节 RV 先天免疫逃避的分子机制的理解。 1. 确定NSP1介导的β-TrCP降解的结构基础和体内活性。尽管 RV NSP1 蛋白具有诱导 IRF3 和/或 β-TrCP 降解的能力，但调节这种降解的机制尚不清楚。最近发现宿主 Cullin-E3 连接酶复合物在 NSP1 降解中发挥着意想不到的作用为此，我们将剖析 NSP1 如何劫持宿主 Cullin-E3 连接酶复合物，诱导 β-。 TrCP 降解，阻断 NF-κB 激活，从而促进同源 RV 复制。 2. 确定菌株和宿主中 VP3 降解 MAVS 的分子机制体外和体内的特定方式。我们之前表明 RV 感染的 ssRNA 副产物是胞质传感器的有效激活剂 RIG-I 和 MDA5，两者均聚集在线粒体抗病毒信号蛋白 (MAVS) 上以传递先天信号意外的初步结果表明 MAVS 是针对的。 RV VP3 蛋白以宿主范围限制 (HRR) 方式进行蛋白酶体降解。在机制层面探索不同 RV 物种的 VP3 和 MAVS 之间复杂的相互作用评估 VP3 介导的 MAVS 降解在促进 RV 体外和体内复制中的重要性。 3. 确定RV NSP1介导的STAT1激活和肠细胞抑制的机制 IFN 对 RV 感染反应的起源。尽管能够有效抑制肠上皮细胞 (IEC) 中 I 型干扰素的诱导，同源 RV 感染仍会在肠道中诱导大量 I 型和 III 型干扰素的产生。表明 RV 必须能够破坏 IFN 介导的抗病毒放大以及阻断 IFN 新发现表明 RV NSP1 可有效抑制 IFN 介导的 STAT1 磷酸化。通过消耗多个 IFN 受体来阻断 STAT1 激活，可能是通过 NSP1 引导的 RV 降解。体外也可阻断未感染细胞中 IFN 介导的 STAT1 激活，但这种效应是否也发生在体内。我们建议鉴定 RV 引发的 I 型和 III 型干扰素的造血细胞和 IEC 起源。我们还将研究 RV 介导的 IFN 受体降解的机制决定因素和抑制 STAT1 激活并确定这些功能的差异是否会导致 RV HRR。