Characterization of Viral Receptors and Signaling Networks in JC Polyomavirus Infection

项目总结 这项拟议的研究的目的是确定JC多瘤病毒(JCPyV) 与宿主细胞受体相互作用导致JCPyV感染，从而导致进行性 多灶性白质脑病(PML)。JCPyV感染了大多数人，并建立了一种 终生的、无症状的健康人肾脏感染。在免疫功能受损的个体中， JCPyV可以传播到中枢神经系统(CNS)，并在胶质细胞中引起裂解性感染，导致 致命的脱髓鞘疾病PML。大约5%的艾滋病毒携带者会患上PML，这被证明是 一种定义为艾滋病的晚期疾病，以及接受免疫调节治疗的疾病的个人，包括 多发性硬化症发生PML的风险很高。PML可在出现症状的一年内致命 发病，特别是当潜在的免疫抑制没有得到治疗，而且目前没有批准的 对这种毁灭性疾病的治疗。JCPyV与细胞受体结合的机制 侵袭宿主细胞引起感染的特征还不是很好。病毒-受体相互作用调节宿主细胞 易感性和疾病发病机制，从而了解JCPyV与宿主细胞受体的相互作用将 对JCPyV入侵和感染宿主细胞的机制提供关键的洞察力。我们之前的工作 阐明JCPyV的进入是由5-羟色胺受体亚家族5-羟色胺2(5-羟色胺2)介导的。 HT2Rs)通过网状蛋白介导的内吞作用和β-arrestin。我们还确定了JCPyV感染可以诱导 5-HT2R的聚集性。有趣的是，G蛋白偶联受体(GPCR)，包括5-HT2Rs，可以聚集到 形成杂二聚体和同源二聚体以及低聚物，这对结构具有重要的功能意义 配体结合界面的组织，内吞机制，以及激活和信号通路。 然而，这一过程对于5-HT2Rs来说并不是很好的特征，以及受体属性如何指导病毒入侵 对宿主细胞和协调复杂的病毒感染过程知之甚少。我们假设 JCPyV感染诱导5-HT2Rs配体特异性簇模式介导JCPyV进入、贩运和 受体激活的信号通路。本研究提出三个相辅相成的具体目标。 计划了解JCPyV利用5-HT2Rs内化到宿主细胞和 篡改细胞信号网络以规范病毒贩运并推动病毒复制。这项研究 将增强我们对JCPyV进入和信号转导的理解，阐明病毒与受体如何相互作用 控制病毒感染和疾病。这些研究还可能发现新的抗病毒靶点或提供理论依据 用于试验使用市场上针对PML的5-HT2R特异性药物。这项工作的成果还将提供 对无包膜病毒进入病毒和激活细胞信号的机制有更广泛的见解 由冠状病毒、疱疹病毒和埃博拉等涉及利用GPCR信号的病毒建立的网络 病毒，这会导致严重的人类疾病。

PROJECT SUMMARY The objective of the proposed research is to determine the mechanisms by which JC polyomavirus (JCPyV) interacts with host-cell receptors to cause JCPyV infection, which leads to the development of progressive multifocal leukoencephalopathy (PML). JCPyV infects the majority of the human population and establishes a lifelong, asymptomatic infection in the kidney of healthy individuals. In immunocompromised individuals, JCPyV can spread to the central nervous system (CNS) and cause a lytic infection in glial cells, resulting in the fatal, demyelinating disease PML. Approximately 5% of individuals with HIV develop PML, which proves to be a terminal AIDS-defining illness, and individuals receiving immunomodulatory therapies for diseases including multiple sclerosis are at heightened risk for PML development. PML can be fatal within one year of symptom onset, especially when underlying immunosuppression is left untreated, and there are currently no approved treatments for this devastating disease. The mechanisms by which JCPyV engages cellular receptors to invade host cells to cause infection is not well characterized. Virus-receptor interactions regulate host cell susceptibility and disease pathogenesis, thus understanding JCPyV interactions with host cell receptors will provide key insight into the mechanisms of JCPyV invasion and infection of host cells. Our previous work elucidated that JCPyV entry is mediated by the 5-hydroxytryptamine 2 subfamily of serotonin receptors (5- HT2Rs) via clathrin-mediated endocytosis and β-arrestin. We also determined that JCPyV infection induces clustering of 5-HT2Rs. Interestingly, G-protein coupled receptors (GPCR), including 5-HT2Rs, can cluster to form hetero- and homodimers as well as oligomers, which is functionally significant to the structural organization of the ligand binding interface, endocytic mechanisms, and activation of and signaling pathways. However, this process is not well characterized for 5-HT2Rs, and how receptor attributes direct viral invasion of host cells and orchestrate the complex processes of viral infection is poorly understood. We hypothesize that JCPyV infection induces ligand-specific cluster patterns of 5-HT2Rs to mediate JCPyV entry, trafficking, and receptor-activated signaling pathways. Three complementary specific aims are proposed in this research plan to understand the mechanisms by which JCPyV utilizes 5-HT2Rs to internalize into host cells and usurp cellular signaling networks to regulate viral trafficking and drive viral replication. This research will enhance our understanding of JCPyV entry and signaling, elucidating how virus-receptor interactions regulate viral infection and disease. These studies could also uncover new antiviral targets or provide rationale for experimental use of on-market 5-HT2R-specific drugs for PML. Outcomes of this work will also provide broader insights into the mechanisms of virus entry of nonenveloped viruses and activation of cellular signaling networks by viruses implicated to utilize GPCR signaling such as coronaviruses, herpesviruses, and Ebola virus, which cause serious human diseases.