Using a novel neonatal mouse model to determine mechanisms of norovirus-induced disease

使用新型新生小鼠模型确定诺如病毒诱发疾病的机制

• 批准号: 10666386
• 负责人: Emily Winesett Helm
• 金额: $ 3.93万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-16 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10666386
• 关键词: Acceleration; Acute; Adult; Animal Model; Antiviral Agents; Area; Attenuated; Biological Models; Biology; Cells; Cellular Tropism; Cessation of life; Childhood; Data; Dependence; Development; Diarrhea; Disease; Enteral; Gastroenteritis; Genetic; Health; Human; Immune; Immune response; Immunocompetent; Immunologic Deficiency Syndromes; In Vitro; Infection; Inflammatory; Interferons; Intestinal permeability; Length; Lymphocyte; Macrophage; Modeling; Mus; Mutation; Nature; Neonatal; Norovirus; Oral; Pathogenicity; Phenotype; Predisposition; Severities; Severity of illness; Symptoms; System; Systemic disease; TNF gene; Testing; Tight Junctions; Tropism; Vaccines; Viral; Virulence; Virulent; Virus; Virus Diseases; Virus Replication; Wild Type Mouse; Work; age group; cellular targeting; clinically relevant; comparative; cytokine; efficacy testing; enteric infection; gut microbiota; improved; in vivo; insight; intestinal epithelium; mouse model; neonatal mice; novel; prevent; response; targeted treatment; therapeutic development; virology

Project Summary/Abstract Norovirus is the leading cause of severe childhood diarrhea around the world and a major cause of acute gastroenteritis in all age groups. There are no currently approved vaccines or targeted therapeutics for norovirus infection and very little is known about the pathogenic mechanisms underlying gastroenteritis symptoms. To gain further understanding of this important virus, murine norovirus has been used as a model system for many years and has led to many significant advances in understanding norovirus biology. However, the absence of symptoms in immunocompetent adult mice infected with murine norovirus limits the applicability of this model to delineation of viral mechanisms of disease. We recently discovered that genetically wild-type neonatal mice develop acute, self-resolving diarrhea when infected with murine norovirus, a disease course that mirrors human norovirus infection. This novel small animal model of norovirus disease represents a major advance in the norovirus field since it will enable a complete characterization of viral disease mechanisms and ultimately serve as a platform to test the efficacy of antiviral compounds in vivo. While developing this new model, we observed differences in disease severity between genetically similar murine norovirus strains enabling identification of viral determinants of norovirus-induced disease. The objectives of this proposal are to elucidate the cellular tropism and pathogenic mechanisms underlying norovirus diarrhea using our novel symptomatic small animal model. In Specific Aim 1, I will test the hypothesis that infection of lymphocytes is critical to norovirus- induced diarrhea. This hypothesis is strongly supported by our in vitro findings revealing that, although virulent and attenuated strains replicate comparably in macrophages, only the virulent strain replicates in lymphocytes. Moreover, mutations abolishing lymphocyte infection in vitro are attenuating in adult interferon-deficient mice. In Specific Aim 2, I will test the hypothesis that virus-induced proinflammatory cytokines cause disruptions in tight junctions maintaining the intestinal epithelial barrier, consequently leading to increased intestinal permeability and diarrhea. This hypothesis is based on our observation that a virulent murine norovirus strain induces significantly more proinflammatory cytokine expression than attenuated strains despite comparable levels of viral replication; and on the well-established ability of proinflammatory cytokines to disrupt tight junctions. Overall, the studies described in this proposal will test our model that norovirus infection of intestinal immune cells induces a host response that is immunopathologic and leads to diarrhea via effects on the intestinal epithelial barrier.

项目概要/摘要 诺如病毒是全世界严重儿童腹泻的主要原因，也是急性腹泻的主要原因。 各个年龄段的肠胃炎。目前尚无批准的诺如病毒疫苗或靶向治疗药物 感染，但对胃肠炎症状的致病机制知之甚少。为了获得 进一步了解这种重要的病毒，鼠诺如病毒多年来一直被用作模型系统 并在理解诺如病毒生物学方面取得了许多重大进展。然而，由于缺乏 感染鼠诺如病毒的免疫活性成年小鼠的症状限制了该模型的适用性 描述疾病的病毒机制。我们最近发现，基因野生型新生小鼠 当感染鼠诺如病毒时，会出现急性、自愈性腹泻，这种疾病过程与人类相似 诺如病毒感染。这种新型诺如病毒疾病小动物模型代表了诺如病毒疾病研究的重大进展 诺如病毒领域，因为它将能够全面表征病毒疾病机制并最终服务 作为测试体内抗病毒化合物功效的平台。在开发这个新模型时，我们观察到 遗传相似的鼠诺如病毒株之间疾病严重程度的差异，从而能够识别病毒 诺如病毒引起的疾病的决定因素。该提案的目的是阐明细胞 使用我们的新型症状小药物来研究诺如病毒腹泻的向性和致病机制 动物模型。在具体目标 1 中，我将检验淋巴细胞感染对诺如病毒至关重要的假设 - 诱发腹泻。我们的体外研究结果有力地支持了这一假设，表明尽管有毒 和减毒株在巨噬细胞中复制相当，只有强毒株在淋巴细胞中复制。 此外，在体外消除淋巴细胞感染的突变在成年干扰素缺陷小鼠中正在减弱。在 具体目标 2，我将检验病毒诱导的促炎细胞因子导致紧密细胞破坏的假设 维持肠上皮屏障的连接，从而导致肠道通透性增加 和腹泻。这一假设是基于我们的观察，即一种强毒力的鼠诺如病毒株会诱导 尽管病毒水平相当，但促炎细胞因子的表达明显高于减毒株 复制；以及促炎细胞因子破坏紧密连接的公认能力。总体而言， 该提案中描述的研究将测试我们的模型，诺如病毒感染肠道免疫细胞会诱导 一种免疫病理性宿主反应，通过影响肠上皮屏障导致腹泻。