RAPID: Identifying the Role of Mucus in COVID-19 Pathogenesis

2019年12月，一种新型冠状病毒（SARS-CoV-2）被发现导致COVID-19，这是一种高度传染性的呼吸道疾病，已在全球迅速传播。美国的病例正在上升，医院有被重症病例淹没的危险，但目前没有具体的治疗方法。提高我们对病毒传播和疾病进展的理解，对于确定应对这一大流行所需的预防措施和治疗方案至关重要。这个项目的重点是粘液，一个关键的宿主因子，及其在感染的两个方面的作用：病毒如何到达和穿透上皮，以及粘液特性如何与症状严重程度相关。该项目采用双管齐下的方法来确定粘液在COVID-19发病机制中的作用，这将开始揭示通过粘液屏障感染的关键步骤。目的1将确定SARS-CoV-2与粘液结合并通过粘液运输的机制，这将有助于了解SARS-CoV-2表面蛋白与天然人黏液蛋白之间的结合，以及这些结合相互作用如何影响病毒通过粘液屏障的运输。目标2将确定区分无症状和重度COVID-19患者的鼻粘液的结构、生化和病毒结合特性，从而鉴定无症状和重度COVID-19患者临床鼻粘液样本的粘液结构（降解、粘蛋白浓度、交联程度）和糖基化谱，以确定这些群体的差异，以及这些特性是否影响病毒的流动性和感染易感性。在不同条件和特定糖苷酶处理下，将通过跟踪嵌入天然粘液和纯化人黏液中的荧光sars - cov -2样颗粒的运动来评估病毒的转运。将使用基于微流体的活细胞荧光显微镜评估粘液渗透性对病毒运输的影响。该项目将促进对病毒颗粒通过黏液屏障的运输现象的理解。这将促进对黏液在COVID-19发病机制中的作用的基本认识，并为治疗靶点的确定提供基础。通过麻省理工学院和波士顿大学之间精心选择的合作，该项目中获得的数据将为生成尖端模型提供必要的结果，以选择性地促进SARS-CoV-2通过粘液屏障。该项目将有助于制定抗击COVID-19大流行所需的流程和行动。这笔拨款是由分配给MPS的冠状病毒援助、救济和经济安全（关怀）法案补充提供的资金提供的。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。

In December 2019, a novel coronavirus (SARS-CoV-2) was identified to cause COVID-19, a highly infectious respiratory disease that has rapidly spread around the world. Cases are on the rise in the United States, and hospitals are in danger of being overwhelmed by severe cases, but there is currently no specific treatment. Improving our understanding of virus transmission and disease progression is critical to identifying the preventative measures and therapeutic options needed to address this pandemic. This project focuses on mucus, a critical host factor, and its role in two aspects of the infection: how the virus reaches and penetrates the epithelium, and how mucus properties relate to symptom severity. This project uses a two-pronged approach to identify the role of mucus in COVID-19 pathogenesis, which will begin to reveal critical steps underlying infection through the mucus barrier. Aim 1 shall identify the mechanisms by which SARS-CoV-2 binds to and transports through mucus, which will establish an understanding of binding between SARS-CoV-2 surface proteins and native human mucins and how these binding interactions affect virus transport across the mucus barrier. Aim 2 shall identify structural, biochemical, and virus binding properties of nasal mucus that distinguish asymptomatic from severe COVID-19 patients, leading to the identification of mucus structure (degradation, mucin concentration, degree of crosslinking) and glycosylation profiles in clinical nasal mucus samples from asymptomatic and severe COVID-19 patients to identify how these groups differ and whether these properties impact virus mobility and susceptibility to infection.Virus transport will be assessed by tracking the motion of fluorescent SARS-CoV-2-like particles embedded within native mucus and purified human mucins under different conditions and treatment with specific glycosidases. Effects of mucus permeability on virus transport will be assessed using microfluidics-based live cell fluorescence microscopy. This project will advance the understanding of a poorly understood transport phenomenon of virus particles through the mucus barrier. This knowledge will advance the fundamental understanding of the role of mucus in COVID-19 pathogenesis and provide the foundation for therapeutic targets. With a carefully-chosen collaboration between MIT and BU, the data obtained within this project will provide essential results needed for the generation of cutting-edge models for selective, facilitated passage of SARS-CoV-2 through the mucus barrier. This project will help the development of processes and actions that are needed to combat the COVID-19 pandemic.This grant is being awarded using funds made available by the Coronavirus Aid, Relief, and Economic Security (CARES) Act supplement allocated to MPS.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.