A Mouse Model to Define Immunovirologic Determinants of Polyomavirus CNS Disease

摘要 进行性多灶性白质脑病(PML)是一种危及生命的脱髓鞘脑病 由JC多瘤病毒(JCPyV)引起的免疫受损个人，JC多瘤病毒是一种普遍存在的人类病原体。不是 有抗JCPyV的试剂可用。在不断扩大的PML相关生物制品纲要中， 那他珠单抗的发生率最高(1-2%)，是多发性硬化症(MS)的不祥并发症 其他受益于使用这种免疫调节剂的复发率大幅下降的患者。药效 停药是PML的唯一治疗选择，通常合并高死亡率的脑炎性疾病 反应。此外，最近还描述了三种非PML JCPyV-CNS疾病。缺乏一种可驯服的 多瘤病毒诱导的中枢神经系统疾病的动物模型是阐明PML的公认瓶颈 发病机制和控制JCPyV的免疫学机制(两者对于识别PML风险都是必不可少的 因素)，以及在组织培养中抑制多瘤病毒复制的抗病毒药物的体内评估。vbl.使用 小鼠多瘤病毒(MuPyV)，我们建立了一种与多瘤病毒相关的天然病毒宿主模型 脱髓鞘。在由父母R01支持的工作中，我们发现了一个相当大的特定于MuPyV的大脑居民- 记忆性CD8 T细胞(BTRM)群。TRM以非循环细胞的形式在全身传播， 在那里，他们提供针对再次感染的前线防御。我们对TRM生物学的理解很大程度上来自于 对粘膜屏障中这些细胞的分析；对非粘膜感染部位的TRM了解甚少， 尤其是那些具有大量不可再生细胞(例如，CNS)的细胞。我们发现了一种关键的联系 CD4T细胞与功能性MuPyV特异性CD8bTRM分化的关系我们的初步数据提供了 我们的中心假设是，IL-21是CD4T细胞为人类免疫缺陷病毒提供的“帮助” 生成特定于MuPyV的CD8 bTRM。CD4T细胞功能不全和IL-21信号缺陷各自导致 表达TRM表型的抗病毒CD8T细胞丢失，在没有补给的情况下无法在脑内存活 从发行量来看。CD4T细胞无辅助抗病毒CD8T细胞的基因表达途径分析 持续性流行性乙型病毒性脑炎显示IL-21和Notch信号通路调节失调，其 通过STAT3实现潜在的融合。MuPyV特异性CD8 bTRM表达功能性Notch受体，其 在没有CD4T细胞帮助的情况下，活化程度会降低。Notch受体最近被报道为 支持建立组织驻留记忆CD8 T细胞。对于特定的目标1，我们假设IL-21 是CD4T细胞提供的帮助引导脑浸润性CD8T分化的主要组成部分 细胞转化为TRM。对于特定的目的2，我们假设IL-21和Notch信号通过STAT3相互作用 激活以产生CD8 bTRM。如果这些假设被证明是正确的，它们将为 维持和维持多瘤病毒中枢神经系统感染的免疫控制机制。

ABSTRACT Progressive Multifocal Leukoencephalopathy (PML) is a life-threatening demyelinating brain disease in immune-compromised individuals caused by the JC polyomavirus (JCPyV), a ubiquitous human pathogen. No anti-JCPyV agents are available. Among the expanding compendium of PML-associated biologics, natalizumab has the highest incidence (1-2%) and is an ominous complication for multiple sclerosis (MS) patients who otherwise benefit from dramatic reductions in relapses using this immunomodulatory agent. Drug withdrawal, the only therapeutic option for PML, is often complicated by a high-mortality cerebral inflammatory reaction. Moreover, three non-PML JCPyV-CNS diseases have recently been described. Lack of a tractable animal model of polyomavirus-induced CNS disease is a well-recognized bottleneck to elucidating PML pathogenesis and the immunological mechanisms that control JCPyV (both essential for identifying PML risk factors), and in vivo evaluation of antiviral agents that inhibit polyomavirus replication in tissue culture. Using mouse polyomavirus (MuPyV), we developed a natural virus-host model of polyomavirus-associated demyelination. In work supported by the parent R01, we found a sizeable MuPyV-specific, brain resident- memory CD8 T cell (bTRM) population. TRM are disseminated throughout the body as non-recirculating cells, where they provide frontline defense against reinfection. Our understanding of TRM biology comes largely from analysis of these cells in mucosal barriers; far less is understood about TRM in nonmucosal sites of infection, particularly those with large numbers of nonrenewable cells (e.g., CNS). We discovered a critical connection between CD4 T cells and differentiation of functional MuPyV-specific CD8 bTRM. Our preliminary data provide strong scientific premise for our central hypothesis that IL-21 is the “help” proffered by CD4 T cells for generating MuPyV-specific CD8 bTRM. CD4 T cell insufficiency and IL-21 signaling-deficiency each resulted in loss of antiviral CD8 T cells expressing a TRM phenotype and inability to survive in the brain without resupply from the circulation. Gene expression pathway analyses of CD4 T cell-unhelped antiviral CD8 T cells during persistent MuPyV encephalitis revealed dysregulation of IL-21 and Notch signaling pathways, and their potential convergence via STAT3. MuPyV-specific CD8 bTRM express functional Notch receptors, whose activation is diminished in the absence of CD4 T cell help. Notch receptors have recently been reported to support establishment of tissue-resident memory CD8 T cells. For Specific Aim 1, we hypothesize that IL-21 is a major component of the help provided by CD4 T cells to guide differentiation of brain-infiltrating CD8 T cells into TRM. For Specific Aim 2, we hypothesize that IL-21 and Notch signaling cooperate via STAT3 activation to generate CD8 bTRM. If these hypotheses prove correct, they will provide essential insights into the mechanisms involved in maintaining and sustaining immunologic control of polyomavirus CNS infection.