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

描述(由申请人提供)：泰勒氏小鼠脑脊髓炎病毒(TMEV)引起一种以脱髓鞘为特征的持续性感染。这种疾病是多发性硬化症最好的动物模型之一。携带两种主要髓鞘蛋白突变的小鼠对持续感染具有抵抗力。TMEV存在于轴突中，并从那里感染髓鞘内的细胞质通道。在髓鞘突变体中没有发生轴突到髓鞘的传播，这表明髓鞘感染是野生型小鼠病毒持续存在所必需的。令人惊讶的是，TMEV从神经元传播到少突胶质细胞并不需要裂解轴突。目前，病毒从轴突转移到髓鞘的机制以及感染髓鞘使持续存在的原因尚未解决。这项研究计划的主要目的是明确髓鞘在TMEV持续存在中的作用，并阐明非溶血性细胞质交换的潜在机制。具体目的：(1)探讨神经元与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：我将在微流室中建立神经元和少突胶质细胞的共培养，将神经元细胞体与有髓轴突分开，并将测试TMEV的轴突到髓鞘的扩散。此外，利用这些微流控共培养，我将确定髓鞘感染是否依赖于受体，并将检查轴突到髓鞘传播所需的遗传要求和细胞途径。此外，我将研究自噬的重要性，并通过感染自噬或髓鞘基因遗传缺陷的小鼠来确定哪些髓鞘成分是维持生存所必需的。公共卫生相关性：髓鞘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。使用研究多发性硬化症的最佳动物模型之一的TMEV进行的实验最近证实，髓鞘对病毒的持久性至关重要。阐明轴突和髓鞘之间胞质扩散的机制将对髓鞘的轴突支持作用提供新的见解，并有助于提高我们对多发性硬化症发病机制的理解。

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.