The Cell Biology of Theiler's Virus Persisstence in CNS

泰勒病毒在中枢神经系统中持续存在的细胞生物学

• 批准号: 7144321
• 负责人: Karla Kirkegaard
• 金额: $ 34.06万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7144321
• 关键词: bone marrow; cell biology; culture; infection; macrophage; murine encephalomyelitis virus; mutant; myelin; neurons; oligodendroglia

DESCRIPTION (provided by applicant): Theiler's virus, a picornavirus, causes a persistent infection of the spinal cord of genetically susceptible mice that is accompanied by chronic infection and primary demyelination. As such, it provides one of the best animal models for immune-mediated demyelination. Theiler's virus first infects neurons, but later persists in oligodendrocytes and macrophage/macroglial cells. This shift from gray to white matter coincides with the appearance of virus-specific immune responses, suggesting that immune pressure keeps the virus out of neurons but is unable to clear it from glial cells. In this application, we propose to test a model in which the virus traffics sequentially from neurons to oligodendrocytes to macrophages, with oligodendrocytes providing an obligatory intermediate in the face of immune pressure. First, we will monitor the time course of Theiler's infection of various cell types in wild-type C3H and in shiverer and rumpshaker mice, which have different severe myelin defects and are resistant to persistent infection. We will examine whether oligodendrocytes, macrophages or both are never infected, or infected only transiently, in the resistant mutant mice. Bone marrow transfer experiments will reveal whether CNS- or bone marrow-derived cells from shiverer and rumpshaker mice confer resistance to persistent infection and in vitro culture of oligodendrocytes and macrophages will reveal whether the intrinsic permissiveness of these cells to viral infection is altered by the mutations. Second, we will determine whether myelin is the portal of entry of the virus into the white matter. We will express viral genomes specifically in neurons in mixed cultures of oligodendrocytes and neurons, and track viral spread into oligodendrocytes in the presence and absence of successful myelination. Experiments performed with female rumpshaker heterozygotes will afford us the possibility to work with natural chimeras in vivo, because the rumpshaker mutation is X-linked. Finally, we will use in vivo labeling methods to monitor the migration of blood-borne macrophages into inflammatory CNS lesions, and determine the frequency with which these newly arrived cells become infected. This will test the possibility that persistence is achieved, in part, by the chronic inflammation that ensures the existence of a renewable host population. Together, this model may prove a paradigm for the functional transfer of infectious material from neurons to oligodendrocytes, and from thence to cells of the immune system.

描述（由申请人提供）：泰勒病毒（一种小核糖核酸病毒）会导致遗传易感小鼠的脊髓持续感染，并伴有慢性感染和原发性脱髓鞘。因此，它提供了免疫介导脱髓鞘的最佳动物模型之一。泰勒病毒首先感染神经元，但随后持续存在于少突胶质细胞和巨噬细胞/巨胶质细胞中。这种从灰质到白质的转变与病毒特异性免疫反应的出现相一致，这表明免疫压力使病毒无法进入神经元，但无法将其从神经胶质细胞中清除。在本申请中，我们建议测试一个模型，其中病毒依次从神经元到少突胶质细胞再到巨噬细胞，少突胶质细胞在面对免疫压力时提供了必要的中间体。首先，我们将监测野生型 C3H 以及 shiverer 和 rumpsshaker 小鼠中各种细胞类型的 Theiler 感染的时间进程，这些小鼠具有不同的严重髓磷脂缺陷并且对持续感染具有抵抗力。我们将检查耐药突变小鼠中的少突胶质细胞、巨噬细胞或两者是否从未被感染，或仅短暂感染。骨髓移植实验将揭示来自颤栗小鼠和摇臀小鼠的中枢神经系统或骨髓来源的细胞是否具有对持续感染的抵抗力，少突胶质细胞和巨噬细胞的体外培养将揭示这些细胞对病毒感染的内在许可性是否因突变而改变。其次，我们将确定髓磷脂是否是病毒进入白质的门户。我们将在少突胶质细胞和神经元混合培养物的神经元中特异性表达病毒基因组，并在存在或不存在成功髓鞘形成的情况下追踪病毒扩散到少突胶质细胞中。用雌性 rumpsshaker 杂合子进行的实验将为我们提供在体内研究天然嵌合体的可能性，因为 rumpsshaker 突变是 X 连锁的。最后，我们将使用体内标记方法监测血源性巨噬细胞向炎症性中枢神经系统病变的迁移，并确定这些新到达的细胞被感染的频率。这将测试持久性的可能性，部分是通过确保可再生宿主群体存在的慢性炎症来实现的。总之，该模型可能证明感染物质从神经元到少突胶质细胞，再从那里到免疫系统细胞的功能转移的范例。