RAPID: Glycocalyx engineering to probe the role of mucin structure in coronavirus transmission and infection

材料研究部的生物材料项目和化学部的生命过程化学项目将资助犹他大学的Jessica R. Kramer博士研究黏液成分在冠状病毒（COV）传播中的作用。冠状病毒相关疾病已成为严重的公共卫生威胁。被感染者咳嗽、打喷嚏甚至说话时的飞沫是病毒传播的主要来源。这些飞沫来自携带病毒的粘膜唾液液，落在下一个潜在宿主（口腔、气道、眼睛）的粘膜上或坚硬的表面上。在那里，病毒被分散为下一次感染。粘液以数百种形式产生，在物种之间甚至人与人之间都有所不同。存在的形式可能会影响病毒通过粘膜的难易程度，特别是因为有些类型直接与冠状病毒结合。粘液形态也会影响空气飞沫中冠状病毒的浓度和活力。该项目的目标是确定导致空气传播和感染增加的粘液形式。这将通过模拟由不同粘液产生的咳嗽飞沫和使用涂有不同粘液的人体细胞来完成。这一知识可能会导致开发新的治疗方法，破坏冠状病毒黏液结合，或识别更容易受到冠状病毒传播和感染的人群。项目技术摘要本课题研究粘蛋白糖蛋白结构在冠状病毒（COV）通过空气传播颗粒、污染物传播以及通过糖萼进入细胞中的作用。上皮组织被保护性粘蛋白包裹，这些保护性粘蛋白分泌形成粘液，并附着在细胞表面形成糖萼。冠状病毒在进入宿主细胞进行复制之前必须穿过这些层。病毒通过空气中喷出的粘膜唾液飞沫传播是主要的传播方式。粘蛋白是由对每个宿主特异性的各种粘附聚糖产生的。这些聚糖改变粘膜唾液液的粘弹性，并直接与冠状病毒刺突蛋白结合。这些因素可能影响病毒在空气中颗粒的装载和活力，并可能影响细胞表面的对接和扩散。然而，这些问题一直具有挑战性，因为天然粘蛋白糖基化定义不清，并且无法通过当前的生物学方法进行调节。PI的实验室将合成具有可调冠状病毒结合聚糖模式的粘蛋白类似物，并将利用它们来设计活细胞表面的糖萼。将模拟咳嗽，并通过液滴形态、病毒载量和活力的表征来研究粘蛋白结构在空气传播中的作用。将在活的上皮细胞上量化细胞表面的对接和扩散以及复制。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。

Project Non-Technical AbstractWith this award, the Biomaterials Program in the Division of Materials Research and the Chemistry of Life Processes Program in the Division of Chemistry are funding Dr. Jessica R. Kramer from The University of Utah to study the role of mucus composition in coronavirus (COV) transmission. COV-related diseases have emerged as a serious public health threat. Airborne droplets from an infected person’s cough, sneeze, or even talking are a major source of viral spread. These droplets stem from virus-laden mucosalivary fluid and land on the mucus membranes of the next potential host (mouth, airway, eyes) or on hard surfaces. There, the virus is dispersed for the next infection. Mucus is produced in hundreds of forms that vary between species, and even person-to-person. The forms present could affect how easily the viruses pass through the mucus membrane, especially since some types bind directly to COVs. Mucus forms could also affect the concentration and viability of COVs in airborne droplets. The goal of this project is to identify the forms of mucus that result in increased airborne COV transmission and infection. This will be accomplished by simulation of cough droplets produced from varied mucus and using human cells coated with varied mucus. This knowledge could lead to development of new therapeutics that disrupt COV-mucus binding, or identify populations more vulnerable to COV transmission and infection. Project Technical AbstractThis research project undertakes study of the role of mucin glycoprotein structures in coronavirus (COV) transmission via airborne particles, fomite objects, and in cellular entry through the glycocalyx. Epithelial tissue is coated with protective mucins that are secreted to form mucus and also tethered to the cell surface to form the glycocalyx. COVs must traverse these layers before entry into host cells for replication. Viral transmission through expelled airborne mucosalivary droplets is a major mode of transmission. Mucins are produced with a variety of attached glycans specific to each host. These glycans alter the viscoelasticity of mucosalivary fluid and directly bind to COV spike proteins. These factors could affect virus loading and viability in airborne particles and could affect docking and diffusion at the cell surface. However, such questions have been challenging to answer because native mucin glycosylation is poorly-defined and not tunable by current biological methods. The PI’s lab will synthesize mucin analogs with tunable COV-binding glycan patterns and will use them to engineer the glycocalyx of live cell surfaces. Coughs will be simulated and the role of mucin structure in airborne respiratory droplet COV transmission will be examined by characterization of droplet morphology, and viral loading and viability. Docking and diffusion at the cell surface, as well as replication, will be quantified on live epithelial cells.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.