EAGER: Investigation of host and viral factors that influence the severity of coronaviral disease

三种冠状病毒（sars - cov、MERS-CoV和SARS-CoV2）已经从动物身上出现，导致人类严重呼吸道疾病。人们对控制疾病严重程度和传播的病毒-宿主相互作用知之甚少，这使社会对COVID-19大流行毫无准备。为了更好地宣传和教育病毒传播和预防科学，需要一种密切模仿SARS-CoV-2感染和发病机制的动物模型。小鼠感染了自己的小鼠特异性冠状病毒[小鼠肝炎病毒（MHV）]，导致呼吸系统疾病，并影响心脏、肝脏和脾脏等其他器官，如COVID-19。本提案将利用COVID-19的MHV模型，在受控条件下了解疾病进展及其相关因素。小鼠模型利用现有的小鼠遗传工具、免疫试剂和详细的病理评估来确定宿主因素，例如与不同疾病严重程度相关的免疫细胞浸润类型和产生的细胞因子。该分析将提供对保护性和有害宿主反应的深入了解，从而可以确定治疗的目标过程。该模型系统的开发有可能成为一种高效且具有成本效益的工具，用于识别和筛选需要升级为更具体的COVID-19模型的治疗和预防策略，从而充分利用与实际使用SARS-CoV2的ABSL-3要求相关的有限基础设施资源。这是一个更广泛的影响，因为它将使社会在寻求COVID-19治疗方法和疫苗方面受益。目前迫切需要在遗传多样性人群中建立各种水平的SARS-CoV2疾病模型。据推测，控制冠状病毒呼吸道感染严重程度的宿主和病毒因素可以通过在不同的小鼠群体中使用自然小鼠冠状病毒感染来确定。MHV是小鼠的天然病原体，它们很好地适应了宿主，在它们的嗜性和疾病表型上都有所不同。在呼吸道中具有不同毒力的MHV-1和MHV-A59引起的病理病变和宿主反应的范围将被表征。八种遗传多样性的协作交叉创始人小鼠品系将被用来代表在大量人类群体中看到的遗传多样性。这些研究将侧重于肺部病理，但也将评估心脏、肝脏、肾脏和脾脏。小鼠将接种MHV-1或MHV-A59。将检查组织的病理变化。纤维化和免疫细胞浸润将通过组织化学染色和免疫组织化学来表征。病毒滴度，血清化学，凝血，中和抗体和细胞因子将被测量。将确定MHV毒株、小鼠毒株、病毒载量、临床疾病、病理病变和免疫反应之间的相关性。这些研究是增加对SARS-CoV-2感染生物学知识的第一步。该RAPID奖由综合有机体系统生物部门的共生、防御和自我识别项目颁发，并使用了《冠状病毒援助、救济和经济安全（关怀）法案》的资金。由分子与细胞生物学遗传机制集群生物学部共同审阅。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Three coronaviruses (SARS-CoV1, MERS-CoV, and SARS-CoV2) have emerged from animals causing severe respiratory disease in humans. Little is known about the virus-host interactions which control disease severity and transmission, leaving society unprepared for the COVID-19 pandemic. An animal model that closely mimics SARS-CoV-2 infection and pathogenesis is needed to better inform and educate about the science of virus transmission and prevention. Mice are infected with their own, mouse-specific coronavirus [mouse hepatitis virus (MHV)] that causes respiratory disease and affects other organs, such as the heart, liver and spleen, like COVID-19. This proposal will utilize a MHV model of COVID-19 to understand disease progression and the factors involved using controlled conditions. The mouse model takes advantage of available mouse genetic tools, immunologic reagents, and detailed pathologic assessments to identify host factors, such as the type of immune cell infiltrates and cytokines produced that are associated with different disease severities. This analysis will provide insight into protective and deleterious host responses, which can identify processes to target for therapeutics. The development of this model system has the potential to be an efficient and cost effective tool to identify and screen treatment and prevention strategies that warrant escalation to more specific COVID-19 models, thereby making the best use of the limited infrastructure resources associated with the ABSL-3 requirements of actual SARS-CoV2 use. This is a Broader Impact because it will benefit society in the quest for COVID-19 therapeutics and vaccines. Models of all levels of SARS-CoV2 disease in genetically diverse populations are urgently needed. It is hypothesized that the host and virus factors controlling the severity of coronavirus respiratory infections can be identified using natural murine coronavirus infections in diverse, yet genetically defined cohorts of mice. MHV are natural pathogens of mice that are well adapted to their host and vary in both their tropisms and their disease phenotype. The range of pathological lesions and host responses caused by MHV-1 and MHV-A59, with different virulence in the respiratory tract, will be characterized. The eight genetically diverse Collaborative Cross founder mouse strains will be used to represent the genetic diversity seen in large human populations. These studies will focus on lung pathology, but the heart, liver, kidney and spleen will also be evaluated. Mice will be inoculated with MHV-1 or MHV-A59. Tissues will be examined for pathologic changes. Fibrosis and immune cell infiltrates will be characterized using histochemical stains and immunohistochemistry. Viral titers, serum chemistry, coagulation, neutralizing antibodies and cytokines will be measured. Correlations between MHV strain, mouse strain, viral load, clinical disease, pathological lesions, and immune reactions will be determined. These studies are the first step to increase knowledge about the biology of SARS-CoV-2 infections. This RAPID award is made by the Symbiosis, Defense, and Self-recognition Program in the BIO Division of Integrative Organismal Systems, and, using funds from the Coronavirus Aid, Relief, and Economic Security (CARES) Act. It was co-reviewed by the BIO Division of Molecular and Cellular Biology Genetic Mechanisms cluster.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.