Adaptive MERS coronavirus-cell entry pathways and their relevance to virulence and antiviral strategies

项目摘要 中东呼吸综合征冠状病毒（MERS-CoV）是一种人畜共患病毒 可能导致潜在合并症患者发生致命疾病。进一步 认识这种呼吸综合征和预防策略将需要一个小的 动物感染模型以及对病毒的进一步了解。该PPG 描述了MERS-CoV疾病的小鼠模型。在这个模型中， 疾病是适应性变异，专门用于小鼠肺部感染。相比之下，非 适应的MERS-CoV在小鼠中引起感染但不引起疾病。的 这个子项目（PPG 2）的中心假设是，小鼠适应的变体可以 通过非适应者无法利用的途径有效地进入宿主细胞 病毒为了解决这一假设，将构建重组MERS-CoV， 评估以确定细胞中的小鼠适应性突变是否介导进入 病毒刺突蛋白与有效的小鼠肺部感染相关。替代MERS-CoV 将构建并评估假病毒，以解决以下重点假设： 小鼠适应性变异体介导了一种“早期”质膜细胞进入， 不适应的病毒无法利用。该项目将剖析机制， 蛋白质介导通过质膜的早期细胞进入与晚期细胞进入 通过内体。选择早期与晚期细胞进入的基础将是 通过鉴定促进或限制任一途径的宿主细胞因子来确定。这 该项目还将确定适当的抗病毒策略，通过早期预防 和晚期病毒细胞进入。所有这些目标的理由是， 了解MERS-CoV细胞进入途径将确定与强大的 感染和疾病，并将提供有关预防感染的最佳方法的见解 和疾病的治疗。

PROJECT SUMMARY The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a zoonotic virus that can cause fatal disease in patients with underlying comorbidities. Further recognition of this respiratory syndrome and prevention strategies will require a small animal infection model as well as an additional understanding of the virus. This PPG describes a mouse model of MERS-CoV disease. In this model, the viruses causing disease are adapted variants, specialized for mouse lung infection. By contrast, non- adapted MERS-CoVs cause infection in the mouse but do not cause disease. The central hypothesis of this subproject (PPG2) is that mouse-adapted variants can efficiently enter host cells through pathways that are not available to the non-adapted viruses. To address this hypothesis, recombinant MERS-CoVs will be constructed and evaluated to determine whether mouse-adaptive mutations in the cell entry-mediating viral spike proteins correlate with efficient mouse lung infection. Surrogate MERS-CoV pseudo-viruses will be constructed and evaluated to address the focused hypothesis that mouse adapted variants mediate an “early” plasma-membrane cell entry that is unavailable to non-adapted viruses. The project will dissect mechanisms by which spike proteins mediate early cell entry through plasma membranes versus late cell entry through endosomes. The basis for selection of early versus late cell entry will be determined by identifying host cell factors promoting or restricting either pathway. This project will also identify appropriate antiviral strategies that operate by preventing early and late virus-cell entry. The rationale for all of these aims is that additional understanding of MERS-CoV cell entry pathways will identify correlates of robust infection and disease, and will also provide insights on the best ways to prevent infection and disease with innovative virus entry inhibitors.