Protection of Mice From Lethal Alphavirus Encephalitis

描述（由申请方提供）：甲病毒是全球人类致命性脑炎的重要原因。许多还被美国公共卫生署指定为B类优先病原体，因为它们可能用作生物恐怖主义制剂。一种甲病毒，辛德毕斯病毒（SV），已在鼠模型中进行了广泛研究。特别地，神经适应株（NSV）在易感宿主中诱导高度可再现的疾病，其具有在7-10天的时间内演变的后肢瘫痪和死亡。SV的所有菌株都靶向脑和脊髓中的神经元，这些细胞的命运决定了神经毒力。此外，未感染的神经元也通过旁观者机制受损，并且宿主免疫应答现在已经涉及病毒发病机制的这一方面。我们知道，小胶质细胞，中枢神经系统（CNS）的内源性巨噬细胞样细胞，在NSV感染后很快被激活，我们现在表明，两种抑制这种小胶质细胞激活过程的不相关药物也可以保护小鼠免受NSV诱导的后肢瘫痪和死亡，而不会对CNS病毒复制或传播产生任何影响。为了更详细地研究这种独特的NSV脑脊髓炎保护形式，我们提出：（1）为了进一步表征神经保护药物在使用仅在明显神经疾病发作时或之后开始给药的治疗方案的NSV感染的小鼠中的有益作用，以表征已知靶向小胶质细胞的其他抗炎剂在我们的模型中的作用，并验证我们所有的保护剂对其他在人类中引起致命性脑炎的新世界甲病毒的作用，（2）研究药物介导的保护免于RSV诱导的后肢麻痹和死亡的组织病理学相关性，并进一步表征每种药物如何影响体内CNS中的小胶质细胞活化和体外小胶质细胞诱导的原代神经元损伤，（3）使用cDNA微阵列方法比较在有或没有保护性药物治疗的情况下来自NSV感染动物的纯化组织小胶质细胞中基因表达的时间模式，以及（4）为了在功能上表征通过cDNA微阵列分析鉴定的受保护性药物治疗方案调节的候选基因，并确定这些候选基因是否有助于体内NSV发病机制，小胶质细胞诱导的体外神经毒性。

DESCRIPTION (provided by applicant): Alphaviruses are important causes of fatal encephalitis in humans worldwide. Many are also designated as Category B Priority Pathogens by the U.S. Public Health Service given their potential use as bioterrorism agents. One alphavirus, Sindbis virus (SV), has been extensively studied in a murine model. In particular, a neuroadapted strain (NSV) induces a highly reproducible disease in susceptible hosts with hindlimb paralysis and death that evolves over a period of 7-10 days. All strains of SV target neurons in the brain and spinal cord, and the fate of these cells determines neurovirulence. Further, non-infected neurons are also damaged via bystander mechanisms, and host immune responses have now been implicated in this aspect of viral pathogenesis. We know that microglia, the endogenous macrophage-like cell of the central nervous system (CNS), become activated soon after NSV infection, and we now show that two unrelated drugs that inhibit this microglial activation process also protect mice from NSV-induced hindlimb paralysis and death without exerting any effect on CNS viral replication or spread. In order to study this unique form of protection against NSV encephalomyelitis in greater detail, we propose: (1) To further characterize the beneficial effects of neuroprotective drugs in NSV-infected mice using treatment regimens where dosing begins only at or after the onset of overt neurologic disease, to characterize the effects of other anti-inflammatory agents known to target microglia in our model, and to verify the effects of all our protective agents against other New World alphaviruses that cause fatal encephalitis in humans, (2) To investigate histopathological correlates of drug-mediated protection from NSV-induced hindlimb paralysis and death, and to further characterize how each drug affects microglial activation in the CNS in vivo and microglial-induced injury of primary neurons iin vitro, (3) To compare temporal patterns of gene expression in purified tissue microglia from NSV-infected animals with or without protective drug treatment using cDNA microarray methodologies, and (4) To functionally characterize candidate genes identified by cDNA microarray analysis that are modulated by protective drug treatment regimens and to determine whether these candidates contribute to NSV pathogenesis in vivo and to microglial-induced neurotoxicity in vitro.