Defense mechanisms against CMV brain infection

描述(申请人提供)：人类巨细胞病毒是一种机会性病原体，会在艾滋病患者中产生毁灭性的中枢神经系统疾病，是先天性脑部疾病最常见的感染性原因。尽管淋巴细胞在清除病毒脑感染中的重要性得到了很好的认识，但最近的数据表明，浸润性T淋巴细胞在病毒感染时受损脑组织的修复中也可能发挥着不可或缺的作用。在这项提议中，需要检验的中心假设是，神经干细胞(NSCs)感染巨细胞病毒会损害其对T淋巴细胞介导的病毒脑感染清除的神经修复反应。本实验旨在研究小鼠巨细胞病毒(MCMV)感染对T细胞和NSCs体内相互作用的影响。为了验证这一假设，我们将(1)确定神经干细胞是否对T淋巴细胞介导的病毒清除有反应。这将通过耗尽CD8+、CD4+和Treg(CD4+CD25+)淋巴细胞亚群，并使用实时生物发光成像检查随后对NSC迁移到MCMV脑感染部位的影响来实现。我们还将研究T细胞介导的免疫反应如何影响受感染动物大脑中特定神经营养素的产生。然后，我们将(2)确定MCMV是否在体内感染内源性NSCs，并损害它们对T淋巴细胞的反应。这些研究将检测MCMV感染对荧光素酶标记的NSCs向IFNg3诱导的趋化因子产生的迁移的影响，并确定MCMV感染的NSCs本身是否是CD8+T细胞介导的清除的目标。最后，我们将(3)确定病毒感染神经干细胞是否会改变它们随后的神经发生。这些研究将调查移植的荧光素酶标记的神经干细胞的持久性，并评估MCMV感染如何改变随后在体内分化后表达的神经细胞标志物(针对神经元、少突胶质细胞或星形胶质细胞)。在最后的研究中，我们将确定抗炎环境是否通过过度表达白细胞介素10和转化生长因子b2来促进再生过程，然后评估神经发生。综上所述，这项竞争性更新申请中提出的研究将为T淋巴细胞和神经干细胞之间在病毒感染后维持健康脑组织中的相互作用提供新的见解。公共卫生相关性人类巨细胞病毒是一种机会性病原体，会在艾滋病患者中产生毁灭性的中枢神经系统疾病，本赠款申请中描述的小鼠模型将帮助我们了解抗病毒免疫反应和大脑修复之间的相互作用。病毒性脑炎后慢性残疾患者完全康复的预后很差，这项建议中概述的实验是及时的，因为目前正在许多神经退行性疾病模型中探索使用神经干细胞修复脑损伤。由于人们认为神经干细胞的功能之一是修复炎症和受损的脑组织，这些细胞可能会提供一种创新的方法来治疗神经艾滋病后的神经病理后遗症，以及其他病毒性脑炎。

DESCRIPTION (provided by applicant): Human cytomegalovirus is an opportunistic pathogen that produces a devastating central nervous system disease in AIDS patients and is the most common infectious cause of congenital brain disorders. Though the importance of lymphocytes in clearing viral brain infection is well appreciated, recent data have suggested that infiltrating T lymphocytes may also play an integral role in repair of brain tissue damaged during viral infection. In this proposal, the central hypothesis to be tested is that cytomegalovirus infection of neural stem cells (NSCs) compromises their neuroreparative response to T lymphocyte-mediated clearance of viral brain infection. The proposed experiments are designed to study the effect of murine cytomegalovirus (MCMV) infection on the interplay between T-cells and NSCs in vivo. To test this hypothesis, we will (1) determine if NSCs respond to T lymphocyte-mediated viral clearance. This will be achieved by depleting CD8+, CD4+, and Treg (CD4+CD25+) lymphocyte subpopulations and examining the subsequent effect on NSC migration to sites of MCMV brain infection using real-time bio-luminescence imaging. We will also investigate how T-cell-mediated immune responses affect the production of select neurotrophins in the brains of infected animals. We will then (2) determine if MCMV infects endogenous NSCs in vivo and compromises their response to T lymphocytes. These studies will examine the effect of MCMV infection on the migration of luciferase-labeled NSCs towards IFNg3-induced chemokine production and determine if MCMV infected NSCs are themselves targets for CD8+ T-cell-mediated clearance. Finally, we will (3) determine if viral infection of NSCs alters their subsequent neurogenesis. These studies will investigate persistence of transplanted luciferase-labeled NSCs and evaluate how MCMV infection alters which neural cell markers (specific for neurons, oligodendrocytes, or astrocytes) are expressed following subsequent differentiation in vivo. In the final studies, we will determine if an anti-inflammatory environment fosters regenerative processes through overexpression of interleukin (IL)-10 and transforming growth factor (TGF)b2, followed by an assessment of neurogenesis. Taken together, the studies proposed in this competitive renewal application will provide new insights into the interactions between T lymphocytes and NSCs in the maintenance of healthy brain tissue following viral infection. PUBLIC HEALTH RELEVANCE Human cytomegalovirus is an opportunistic pathogen that produces a devastating central nervous system disease in AIDS patients and the murine models described in this grant application will help us to understand interactions between antiviral immune responses and brain repair. The prognosis for full recovery in patients suffering from chronic disability following viral encephalitis is poor and the experiments outlined in this proposal are timely because the use of neural stem cells to repair brain damage is currently being explored in numerous models of neurodegenerative diseases. Because it is believed that one function of neural stem cells is to repair inflamed and damaged brain tissue, these cells may offer an innovative approach to treat the neuropathological sequelae subsequent to neuroAIDS, as well as other viral encephalitis.