The role of microglia as antigen presenting cells in Globoid Cell Leukodystrophy

摘要 球样细胞脑白质营养不良（GLD）是一种脱髓鞘中枢神经系统（CNS）疾病， 99%的儿童在5岁前死亡。GLD半乳糖苷酶功能缺失突变 导致脂质精神病的毒性积聚，目前认为这是发展的基础。 疾病在GLD中出现的行为和认知缺陷的快速进展对这两个患者都是毁灭性的 然而，目前的治疗在调节这些症状方面的成功有限。因此有 关键是进一步了解与这种疾病的病理学相关的复杂细胞变化， 为这些患者开发成功的疗法。我们的实验室最近发现了CD8+ T细胞在免疫系统中的新作用。 GLD的病理学，然而，这些CD8+ T细胞的募集和活化的机制 不明众所周知，小胶质细胞增生是GLD神经病理学的一个突出特征，我们的初步数据显示， 表明活化的CD68+小胶质细胞在脱髓鞘病变中与CD8+ T细胞在解剖学上成簇， GLD。我们还发现，当暴露于 精神碱总之，这些发现表明，小胶质细胞是一种合理的抗原呈递细胞类型 导致GLD中的CD8+ T细胞活化和神经病理学。我们假设小胶质细胞MHCI 表达有助于GLD中的CD8+ T细胞活化。因此，在本提案中，我们将定义和测试 小胶质细胞MHC I在GLD神经病理学和CD8+ T细胞活化中的作用。在目标1中，我们将定义 小胶质细胞MHC I表达的时间和解剖表达模式在GLD小鼠模型中， 疾病的时间进程。我们还将使用成像质量细胞术来证实这些发现，使用人类 GLD神经标本来解释我们的发现。在目标2中，我们将确定小胶质细胞MHC I功能的作用， 使用小胶质细胞特异性MHCI敲除的抽搐小鼠的神经病理学和CD8+ T细胞应答 在GLD小鼠模型中对小鼠进行研究，以研究对疾病进程、神经病理学和CD8+ T细胞的影响 应答我们还将功能性地检查Psychosine引导小胶质细胞MHC I抗原的能力， 呈递和CD8+ T细胞活化。这个项目的长期目标是了解 GLD神经病理学中的小胶质细胞抗原呈递。这个项目的预期影响可能是我们的 思考这种无法治愈的疾病中脱髓鞘的本质以及小胶质细胞在神经病理学中的作用。 本申请的培训目标将提供神经免疫学方面的技能和培训， 临床和专业目标，指向我作为一名医生科学家的未来。为了实现这些目标， 翻译项目将利用强大的知识环境和独特的机会 在康州大学医学院和赞助商的实验室里。总体而言，本提案的预期成果将 培养和支持我的职业抱负，以实现神经和免疫相互作用的培训， 为神经疾病领域做出贡献。

ABSTRACT Globoid Cell Leukodystrophy (GLD) is a demyelinating central nervous system (CNS) disease that results in death in 99% of children before the age of 5 years old. Loss of function mutation in galactocerebrosidase in GLD leads to a toxic build-up of the lipid psychosine, which is currently thought to underlie the development of this disease. The rapid progression of behavioral and cognitive deficits present in GLD is devastating for both patients and families, however current treatments have limited success at modulating these symptoms. Therefore, it is critical to further understand the complex cellular changes associated with the pathology of this disease to develop successful therapies for these patients. Our lab has recently identified a novel role for CD8+ T cells in the pathology of GLD, however the mechanism underlying the recruitment and activation of these CD8+ T-cells is unknown. It is known that microgliosis is a prominent feature of GLD neuropathology and our preliminary data indicate that activated CD68+ microglia are anatomically clustered with CD8+ T-cells in demyelinated lesions in GLD. We also find that microglia upregulate major histocompatibility complex class I (MHC I) when exposed to psychosine. Together, these findings indicate that microglia are a plausible antigen presenting cell type contributing to CD8+ T-cell activation and neuropathology in GLD. We hypothesize that microglial MHC I expression contributes CD8+ T-cell activation in GLD. Accordingly, in this proposal, we will define and test the role of microglial MHC I on GLD neuropathology and CD8+ T-cells activation. In Aim 1, we will define the temporal and anatomical expression patterns of microglial MHC I expression in a GLD mouse model over the time course of disease. We will also use imaging mass cytometry to corroborate these findings using human GLD neurospecimens to translate our findings. In Aim 2, we will determine the role of microglial MHC I function to neuropathology and CD8+ T cell responses in twitcher mice using microglial cell-specific MHC I knockout mice in the GLD mouse model to investigate effects on disease course, neuropathology and CD8+ T-cell responses. We will also functionally examine the capability of psychosine to direct microglial MHC I antigen presentation and CD8+ T-cell activation. The long-term goal of this project is to understand the novel role of microglial antigen presentation in GLD neuropathology. The expected impact of this project may be a shift in our thinking on the nature of demyelination in this untreatable disease and the role of microglia in neuropathology. The training goals of this application will provide both skills and training in neuroimmunology and to enhance clinical, and professional goals directed toward my future as a physician scientist. Toward these goals, this highly translational project will take advantage of a strong intellectual environment and unique opportunities available at UConn School of Medicine and in the sponsor's lab. Collectively, the expected outcomes of this proposal will foster and support my career aspirations to achieve training in neurological and immunological interactions and to contribute to the field of neurological disease.