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

• 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
• 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

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.

项目摘要/摘要 轮状病毒（RVS）是高度感染性的病毒，因为它们是最常见的 幼儿严重胃肠炎的原因。我们将讲述轮式病理学的三个基本主题 （RV）将扩大我们对调节RV先天免疫进化的分子机制的理解。 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蛋白有充分记录的IRF3和/或β-TRCP降解能力，但 调查这种降解的机制尚不清楚。人RV NSP1专门针对β-TRCP。我们 最近已经确定了宿主cullin-e3连接酶复合物在NSP1降解中的意外作用 功能。在此目标中，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，块NF-κB激活，从而促进同源RV复制。 2。确定VP3在菌株和宿主中通过VP3降解的分子机制 体外和体内的特定方式。 我们先前表明，来自RV感染的SSRNA副产品是胞质传感器的潜在激活剂 RIG-I和MDA5，两者都在线粒体抗病毒信号蛋白（MAVS）上收敛以继承先天 信号传导和影响IFN表达。意想不到的初步发现表明，MAV是针对的 RV VP3蛋白的蛋白酶体降解以受宿主范围限制（HRR）方式降解。我们会在这里 探索机械水平上不同RV物种的VP3和MAV之间的复杂相互作用， 评估VP3介导的MAV降解在体外和体内促进RV复制中的重要性。 3。确定RV NSP1介导的STAT1激活抑制和肠细胞的机制 IFN对RV感染的反应的起源。 尽管能够有效抑制肠上皮细胞（IEC）中I型IFN的诱导，但 同源RV感染仍然诱导肠道中的I型和III型IFN水平。这个IFN生产 表明RV必须能够颠覆IFN介导的抗病毒扩增并阻止IFN 就职。 RV NSP1有效抑制IFN介导的STAT1磷酸化。新发现表示RV 通过耗尽多个IFN受体（可能是通过NSP1定向降解）来阻止STAT1激活。 RV可以 还可以在体外阻断未感染的细胞中IFN指导的STAT1激活。这种效果是否也发生在体内 未知。我们建议识别RV引起的I和III IFN的造血细胞和IEC起源 感染。我们还将检查RV介导的IFN受体降解和 抑制STAT1激活并确定这些功能的差异是否有助于RV HRR。