The role of neuronal maturation on antiviral type I interferon pathway activity.

描述(申请人提供)：嗜神经性虫媒病毒是全球病毒性脑炎的主要病原体，由于其广泛传播的潜力和目前缺乏有效的抗病毒药物，是一个主要的公共卫生问题。虫媒病毒性脑炎在儿童中尤其具有破坏性，与成年人相比，他们更容易患上严重的脑炎和永久性的神经后遗症。这种与年龄相关的临床表现的显著差异在细胞和分子水平上仍然知之甚少。在小鼠模型中观察到对虫媒病毒的依赖成熟的易感性，在该模型中，神经系统疾病的严重程度与中枢神经系统(CNS)的病毒滴度呈正相关。令人惊讶的是，在缺乏外周和适应性免疫防御的情况下，病毒复制增加在未成熟的感染中枢神经系统中持续存在。这些数据支持这样的假设，即在病毒复制的部位--中枢神经系统神经元，中枢神经系统对虫媒病毒感染的先天性免疫反应发生了成熟相关的变化。基因敲除研究已经阐明了I型干扰素途径对中枢神经系统内虫媒病毒限制的重要性，I型干扰素途径是一种经典的细胞固有抗病毒途径。我们的实验室进一步证明，在人类神经元中，抗病毒I型干扰素途径的活性是成熟依赖的。我们使用分化的人类神经母细胞瘤细胞表明，未成熟神经元对I型干扰素治疗不那么敏感，这导致对西方马脑炎病毒(Weev)的易感性增加。这项建议的目的是扩展我们之前的结果，并研究人类神经前体细胞(NPC)和成熟人类神经元中抗病毒I型干扰素途径的活性。核祖细胞在未成熟的中枢神经系统中富含；并在体内被虫媒病毒特异性靶向。然而，人鼻咽癌细胞的天然抗虫媒病毒功能尚未得到直接评估。我们假设，与成熟神经元相比，NPC降低了I型干扰素途径成分的表达，从而导致对I型干扰素的反应性降低，并增加了对Weev的易感性。这一假说将通过两个特定的目的来检验：1)检测人神经前体细胞和成熟的人类神经元中I型干扰素途径组件的表达和功能。2)在Weev感染的背景下，检测神经前体细胞与成熟神经元的先天免疫功能。这项提案将调查人类鼻咽癌天生的抗Weev能力。最终，我们的结果可以提供一种新的机制来解释儿童中枢神经系统虫媒病毒感染的严重性。

DESCRIPTION (provided by applicant): Neurotropic arboviruses are the leading causative agents of iral encephalitis worldwide and are a major public health concern due to their potential for wide dissemination and the current lack of effective antiviral agents. Arboviral encephalitis is particularly devastating in children, who more frequently develop severe encephalitic disease and permanent neurologic sequelae in comparison to adults. This dramatic age- related difference in clinical presentation remains poorly understood at the cellular and molecular level. Maturation-dependent susceptibility to arbovirus is observed in the mouse model, where neurologic disease severity correlates positively with viral titer in the central nervous system (CNS). Surprisingly, in the absence of peripheral and adaptive immune defenses, increased viral replication persists in the immature infected CNS. These data support the hypothesis that maturation-dependent changes occur in the innate immune response of the CNS to arbovirus infection at the site of viral replication, the CNS neuron. Knockout studies have elucidated the importance of the type I IFN pathway, a classic cellular innate antiviral pathway, on arbovirus restriction within the CNS. Our laboratory has further demonstrated that antiviral type I IFN pathway activity is maturation-dependent in human neurons. We have shown using differentiated human neuroblastoma cells that immature neurons are less sensitive to type I IFN treatment, which results in increased susceptibility to western equine encephalitis virus (WEEV). The goal of this proposal is to extend our previous results and investigate antiviral type I IFN pathway activity in human neuroprogenitor cells (NPCs) and mature human neurons. NPCs are enriched in the immature CNS; and specifically targeted by arbovirus in vivo. However, the innate anti-arboviral function of human NPCs has yet to be directly assessed. We hypothesize that, in comparison to mature neurons, NPCs have decreased type I IFN pathway component expression, which results in decreased response to type I IFN and increased susceptibility to WEEV. This hypothesis will be tested through two specific aims: 1) Examine the expression and function of type I IFN pathway components in human NPCs versus mature human neurons. 2) Examine the innate immune function of NPCs versus mature neurons In the context of WEEV infection. This proposal will investigate the innate anti-WEEV competency of human NPCs. Ultimately our results could provide a novel mechanism to explain the severity of arbovirus infection in the pediatric CNS.