Fate of neurons following immune-mediated viral clearance

描述（由申请人提供）：尽管有大量病毒可以感染人脑，并且越来越怀疑某些嗜神经性病原体在慢性神经退行性疾病中起直接或促成作用，但对感染后神经元的命运知之甚少。据推测，神经元可以在感染和免疫事件中存活，导致治愈的细胞在功能上与感染前的表型无法区分，尽管这还没有经过实验测试。虽然有大量证据表明，免疫活性小鼠在CNS内产生保护性反应，解决了病毒感染，导致几乎没有明显的炎症损伤和明显的无损伤生存，但两个关键问题仍未得到回答，这是该提议的基础。第一：事实上，神经元能在抗病毒免疫反应中存活下来吗？第二：如果神经元可以被病毒治愈，那么它们在功能上有能力吗？这些问题将使用良好表征的小鼠系统（同源Cre报告小鼠）来解决，以随时间推移跟踪神经元病毒感染的后果。被两种嗜神经RNA病毒（麻疹或狂犬病）之一感染的神经元将通过荧光信号从红色到绿色的永久变化而被“标记”。然后，在存在或不存在有效免疫应答的情况下，可以在整个感染过程中监测这些神经元。此外，标记的（绿色）神经元可以通过激光捕获显微切割分离，用于随后的基因和蛋白质表达分析。鉴定、分离和表征活跃感染的神经元或先前感染的已被宿主免疫应答治愈的神经元的能力将允许更精确的研究来定义包括年龄、神经元亚型、病毒类型和免疫效应物在内的变量如何影响CNS神经元存活和功能。最后，考虑到该系统可以广泛应用于几乎任何CNS病毒感染的小鼠模型，我们相信有可能在神经病毒学和神经发病机制领域取得重大进展。

DESCRIPTION (provided by applicant): Despite the large number of viruses that can infect the human brain, and the growing suspicion that some neurotropic pathogens play a direct or contributory role in chronic neurodegenerative diseases, little is known about the fate of neurons following infection. It has been surmised that neurons can survive an infection and immunity event, resulting in cured cells that are functionally indistinguishable from the pre-infection phonotype, though this has not been experimentally tested. While there is abundant evidence that immunocompetent mice mount a protective response within the CNS that resolves a viral infection, leading to little overt inflammatory damage and apparent impairment-free survival, two critical questions remain unanswered, which are the basis for this proposal. First: do neurons, in fact, survive the anti- viral immune response? Second: If neurons can be cured of a virus, are they functionally competent? These questions will be addressed using a well-characterized mouse system (congenic Cre reporter mice) to follow the consequences of viral infection of neurons over time. Neurons that have been infected with one of two neurotropic RNA viruses (measles or rabies) will be "marked" by a permanent change in fluorescence signal from red to green. These neurons can then be monitored throughout the infection course in the presence or absence of a competent immune response. Moreover, marked (green) neurons can be isolated by laser capture microdissection for subsequent gene and protein expression analyses. The ability to identify, isolate and characterize actively infected neurons or previously infected neurons that have been cured by the host immune response will allow for more precise studies to define how variables including age, neuronal subtype, virus type, and immune effectors impact on CNS neuron survival and function. Finally, given that this system can be broadly applied to virtually any mouse model of CNS viral infection, we believe there is the potential to enable major advances in the fields of neurovirology and neuropathogenesis.