Role of CD8 T cell-mediated Pathology in Globoid Cell Leukodystrophy

摘要 球样细胞脑白质营养不良（GLD）或克拉伯病是一种致命的遗传性中枢神经系统脱髓鞘疾病， 神经系统感染，每100，000名活产婴儿中就有1人感染，无法治愈或有效的长期治疗。GLD是由 由于半乳糖神经酰胺酶（galc）基因的功能丧失突变， 导致其底物（一种称为半乳糖基鞘氨醇或“psychosine”的脂质）的毒性积累。三嗪 细胞毒性被认为是GLD中几种关键病理的基础。GLD的神经病理学特征为： 严重的脱髓鞘和炎症然而，这些过程的分子细节是有限的， 很少有治疗选择。两组脱髓鞘病变中CD8+ T细胞的早期组织学证据， 小鼠脑和人类GLD脑表明了适应性免疫在这种疾病中的作用。但 先前尚未确定⑶ 8 + T细胞在GLD中的功能。为了弥补我们知识上的差距，我们 通过流式细胞术分析了ticker小鼠CNS组织中T细胞群变化的时间 模型，并与野生型同窝仔进行比较。我们发现，T细胞的快速和持久的升高， 与出生后第21天（P21）临床疾病发作一致的twi CNS。这些数据 在twi和wt同窝出生的脑组织上使用单细胞RNA测序证实，从中鉴定出9倍的 在P21时Twi小鼠脑中的CD8+ T细胞增加。我们的转录组学数据还定义了CD8+群体 如细胞毒性T淋巴细胞（CTL）。为了测试CD8+ CTL在twi小鼠中的GLD样疾病中的功能，我们 通过向twi小鼠施用抗CD8抗体来耗尽CD8+ T细胞，并发现这种治疗有效地 预防疾病发作，保持健康并完全预防CNS脱髓鞘，同时还 减弱脑和血液中的促炎细胞因子水平。这些新的高度翻译的数据 这预示着CD8+ T细胞在GLD中的致病作用，并为我们的总体假设奠定了基础，即CD8+ T细胞在GLD中的致病作用可能是CD8+ T细胞在GLD中的致病作用。 T细胞在GLD中是致病性的，并直接导致疾病。因此，目标1将描述 Twi小鼠中CD8+ T细胞的空间和时间发育，并挑战CD8+ T细胞的贡献 使用基因敲除小鼠品系，然后评估临床、生化和病理结果。目标2将定义 通过评估CD4+ T细胞对CD8+ T细胞介导的免疫应答的贡献， 使用靶向消耗和遗传策略在twi小鼠中的免疫力。目标3将确定和描绘时间， 和定位对真实抗原应答的T细胞，使用T细胞β链VDJ检测T细胞的克隆性 表型分型，然后使用转基因报告小鼠鉴定抗原呈递细胞类型的性质。 这些多学科研究将探讨以前未被认识到的CD8+ T细胞神经炎性 在GLD的回答。这些研究的结果有望填补我们对这一问题的认识上的一个重要空白。 CD8+ T细胞介导的发育的基本细胞病理学机制 神经病理学和GLD疾病。

Abstract Globoid cell leukodystrophy (GLD) or Krabbe's disease is a fatal genetic demyelinating disease of the central nervous system affecting 1 in 100,000 live births with no cure or effective long-term treatment. GLD is caused by loss-of-function mutations in the galactosylceramidase (galc) gene, where loss of GALC enzymatic function results in toxic accumulation of its substrate, a lipid called galactosylsphingosine or `psychosine'. Psychosine cytotoxicity is considered the basis of several key pathologies in GLD. Neuropathology in GLD is marked by profound demyelination and inflammation. However, molecular details of these processes are limited, leaving few therapeutic options. Early histological evidence for CD8+ T cells within demyelinated lesions in both the twi mouse brain and human GLD brain had suggested a role for adaptive immunity in this disease. However, the function of CD8+ T cells in GLD has not been previously determined. To address this gap in our knowledge, we analyzed the timing of T cell population changes by flow cytometry in CNS tissues from the twitcher mouse model of GLD and compared with wt littermates. We identified a rapid and protracted elevation of T cells in the twi CNS that was coincident with the onset of clinical disease at postnatal day 21 (P21). These data were confirmed using single-cell RNA sequencing on twi and wt littermate brain tissues from which identified a 9-fold increase in CD8+ T cells in twi mouse brains at P21. Our transcriptomic data also defined the CD8+ population as cytotoxic T lymphocytes (CTLs). To test the function of CD8+ CTLs in GLD-like disease in twi mice, we depleted CD8+ T cells by administering anti-CD8 antibody to twi mice and found that this treatment effectively prevented disease onset, preserved wellness and completely prevented CNS demyelination while also attenuating pro-inflammatory cytokine levels in brain and blood. These novel and highly translational data portend a pathogenic role for CD8+ T cells in GLD and underlie the basis for our overall hypothesis that CD8+ T cells are pathogenic in GLD and directly contribute to disease. Accordingly, Aim 1 will characterize the spatial and temporal development of CD8+ T cells in twi mice and challenge the contribution of CD8+ T cells using knockout mouse lines to then assess clinical, biochemical, and pathological outcomes. Aim 2 will define the overall nature of adaptive immunity by evaluating contribution of CD4+ T cells to CD8+ T cell-mediated immunity in twi mice using targeted depletion and genetic strategies. Aim 3 will identify and profile the timing, and location T cells responding to authentic antigen, the clonality of the T cells using T cell β chain VDJ phenotyping, and then identify the nature of the antigen presenting cell types using transgenic reporter mice. These multi-disciplinary studies will interrogate a previously unrecognized CD8+ T cell neuroinflammatory response in GLD. Outcomes of these studies are expected to fill an important gap in our understanding on the fundamental cellular pathological mechanisms underlying the development CD8+ T cell mediated neuropathology and disease in GLD.