Axon-to-myelin spread and persistence of Theiler's murine encephalomyelitis virus

描述（由申请人提供）：Theiler的小鼠脑脊髓炎病毒（TMEV）引起以脱髓鞘为特征的持续性感染。此病是多发性硬化症的最佳动物模型之一。在两种主要髓磷脂蛋白中任何一种发生突变的小鼠都能抵抗持续感染。TMEV存在于轴突，并从那里感染髓鞘内的细胞质通道。轴突到髓磷脂的扩散不会发生在髓磷脂突变体中，这表明在野生型小鼠中，髓磷脂的感染是病毒持续存在所必需的。令人惊讶的是，TMEV从神经元向少突胶质细胞的扩散并不需要轴突的断裂。目前，病毒从轴突转移到髓磷脂的机制以及髓磷脂感染使其持续存在的原因尚不清楚。本研究计划的主要目的是确定髓磷脂在TMEV持续性中的作用，并阐明非溶性细胞质交换的潜在机制。具体目的：(1)探讨神经元和少突胶质细胞共培养的轴突-髓鞘病毒传播机制。(2)确定神经元感染、轴突向髓鞘扩散和持续感染的遗传要求。研究设计：我将在微流体室中建立神经元和少突胶质细胞共培养，将神经元细胞体与有髓鞘轴突分离，并将测试TMEV轴突到髓鞘的扩散。此外，使用这些微流体共培养，我将确定髓鞘感染是否依赖于受体，并将检查轴突到髓鞘扩散所需的遗传要求和细胞途径。此外，我将研究自噬的重要性，并通过感染基因上缺乏自噬或髓磷脂基因的小鼠来确定哪些髓磷脂成分对持久性是必要的。公共卫生相关性：髓磷脂是中枢神经系统的重要组成部分，也是多发性硬化症的主要靶点。TMEV是研究多发性硬化症的最佳动物模型之一。最近，使用TMEV进行的实验证实，髓磷脂对病毒的持久性至关重要。阐明轴突和髓磷脂之间细胞质扩散的机制将揭示髓磷脂支持轴突作用的新见解，并可以提高我们对多发性硬化症病理的理解。

DESCRIPTION (provided by applicant): Theiler's murine encephalomyelitis virus (TMEV) causes a persistent infection characterized by demyelination. This disease is one of the best animal models of multiple sclerosis. Mice bearing mutations in either of two major myelin proteins are resistant to persistent infection. TMEV is present in the axon and, from there, can infect cytoplasmic channels within myelin. Axon-to-myelin spread does not occur in myelin mutants, indicating that the infection of myelin is required for viral persistence in wild-type mice. Surprisingly, spread of TMEV from neurons to oligodendrocyte does not require lysis of the axons. Currently, the mechanism by which the virus transfers from axon to myelin and the reason why infection of myelin enables persistence are unresolved. The main objective of this research plan is to define the role of myelin in persistence of TMEV and to elucidate a potential mechanism for non-lytic cytoplasmic exchange. Specific Aims: (1) To investigate the mechanism of axon-to-myelin viral spread using co-cultured neurons and oligodendrocytes. (2) To determine the genetic requirements of neuronal infection, of axon-to-myelin spread and of persistent infection. Study Design: I will establish neuron and oligodendrocyte co-cultures in microfluidic chambers that separate the neuronal cell bodies from myelinated axons, and will test axon-to-myelin spread of TMEV. Also, using these microfluidic co-cultures, I will determine if myelin infection is receptor-dependent and will examine genetic requirements and cellular pathways necessary for axon-to-myelin spread. Additionally, I will examine the importance of autophagy and determine which myelin components are necessary for persistence by infecting mice that are genetically deficient for autophagy or myelin genes. PUBLIC HEALTH RELEVANCE: Myelin is a vital component of the central nervous system and the main target in multiple sclerosis. Experiments using TMEV, one of the best animal models for the study of multiple sclerosis, have recently established that myelin is critical for viral persistence. Elucidating the mechanism of cytoplasmic spread between axons and myelin will reveal novel insights into the axon-supporting role of myelin and could improve our understanding of the pathology of multiple sclerosis.