CNS Exosomes-Mediated Adaptive Immunity in Alzheimer's Disease (AD)

中枢神经系统外泌体介导的阿尔茨海默病 (AD) 适应性免疫

• 批准号: 10515429
• 负责人: ALEXEI DEGTEREV
• 金额: $ 93.36万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10515429
• 关键词: Alzheimer' s Disease; Alzheimer' s disease antigen; Alzheimer' s disease brain; Alzheimer' s disease model; Animal Disease Models; Antigens; Astrocytes; Autopsy; Axon; B-Lymphocytes; Biochemical; Blood; Blood Circulation; Blood Vessels; Brain; CD8-Positive T-Lymphocytes; Cells; Clonality; Data; Detection; Endosomes; Engineering; Future; Genes; Glutamate Transporter; Human; Immune; Immune response; In Vitro; Infiltration; Injections; Label; Mediating; Medical; Microglia; Molecular; Multivesicular Body; Mus; Mutate; Myeloid Cells; Natural Immunity; Neurodegenerative Disorders; Neurofibrillary Tangles; Neurons; Pathogenesis; Pathologic; Pathway interactions; Peripheral; Play; Population; Proteins; Reporter; Role; Senile Plaques; Serum; Signal Transduction; Societies; T-Cell Activation; T-Lymphocyte; Travel; Vesicle; Virus; adaptive immunity; aquaporin 4; base; brain parenchyma; cell type; exosome; extracellular; extracellular vesicles; foot; hyperphosphorylated tau; immunogenic; in vivo; in vivo two-photon imaging; mouse genetics; myelination; neoplastic cell; neuroinflammation; novel; single-cell RNA sequencing; therapeutic development; tool

Abstract Alzheimer’s disease (AD) remains one of the most unmet medical challenges in our society. In the AD, neuroinflammation has been increasingly recognized to play a central role in the pathogenesis of AD, in addition to extracellular amyloid plaques and hyperphosphorylated tau based neurofibrillary tangles. Although the role of innate immunity especially represented by microglia is well-established in AD, it is far less understood and established about whether and how the T or B cell-mediated adaptive immunity is involved in AD pathogenesis. In particular, whether there are brain- and AD-specific antigens to activate adaptive immunity and how these antigens travel to peripheral remain to be investigated. Exosomes (size 40-100 nm), a major type of secreted extracellular vesicles (EVs), are derived from intraluminal vesicles (ILV) that are budded inwardly from the early endosomal compartment and are released from multiple vesicular bodies (MVB) during the maturation of endosomes. EVs and exosomes secreted from various CNS cell types have emerged as a novel and important intercellular pathway in the. Exosome-mediated secretion has also been implicated in initiation and propagation in AD. Although exosomes secreted from various peripheral cell types especially immune and tumor cells trigger immune responses, whether and how CNS-derived exosomes are immunogenic remains unexplored. By employing cell-type specific ILV/exosome reporter (hCD63-GFPf/f) mice we recently generated, we showed that astroglia-derived exosomes are associated with Aquaporin 4+ (Aqp4+) perivascular end feet/blood vessel in the brain. hCD63-GFP+ astroglial exosomes can also be detected in blood serum of LPS-injected (but not control) Glast-CreER+CD63-GFPf/+ mice. Excitingly, exosomes secreted from “reactive” astroglia (RAEs) strongly activate CD4+ and CD8+ T cells in vitro and in vivo. Based on previous studies and our preliminary results, we propose to investigate the following aims: 1) Determine pathological efflux of CNS cell-type specific exosomes from brain and their entry into peripheral circulation in AD models; 2) Determine antigenicity of AD- relevant astroglial exosomes in activating T cells in vitro and in vivo. We have generated a large amount of preliminary data to support our rationales and to demonstrate feasibility for proposed aims. We will employ mouse genetics, virus injections, immunohistochemical (IHC) analysis and in vivo two-photon imaging, primary cultures, FACS, and biochemical approaches to investigate these two aims. Results from this project will determine the efflux changes of neuron or astroglial exosomes from the brain and these exosomes’ entry into peripheral circulation in AD models. In addition, our current study will investigate how T cells respond to “reactive” astroglial exosomes. As reactive astroglia is commonly observed in neurodegenerative diseases including AD, this will potentially unveil new mechanisms how T cells are involved in AD pathogenesis and help define specific brain signals to activate T cells in AD, which subsequently facilitate the therapeutic development.

抽象的 阿尔茨海默病（AD）仍然是我们社会中最未解决的医学挑战之一。在公元， 人们越来越认识到神经炎症在 AD 的发病机制中发挥着核心作用，此外 细胞外淀粉样斑块和基于过度磷酸化 tau 的神经原纤维缠结。虽然角色 先天免疫，特别是以小胶质细胞为代表的先天免疫在 AD 中已得到充分证实，但人们对它的了解却少得多，而且 确定 T 或 B 细胞介导的适应性免疫是否以及如何参与 AD 发病机制。 特别是，是否存在大脑和 AD 特异性抗原来激活适应性免疫以及这些抗原如何激活 抗原传播到外周仍有待研究。外泌体（大小 40-100 nm），一种主要的分泌型 细胞外囊泡（EV）源自管腔内囊泡（ILV），从早期向内出芽 内体区室并在成熟过程中从多个囊泡体（MVB）中释放出来 内体。由各种 CNS 细胞类型分泌的 EV 和外泌体已成为一种新颖且重要的 细胞间通路中。外泌体介导的分泌也与起始和传播有关 在公元。尽管外泌体由各种外周细胞类型尤其是免疫细胞和肿瘤细胞分泌 免疫反应，中枢神经系统衍生的外泌体是否以及如何具有免疫原性仍有待探索。 通过使用我们最近培育的细胞类型特异性 ILV/外泌体报告基因 (hCD63-GFPf/f) 小鼠，我们 显示星形胶质细胞衍生的外泌体与水通道蛋白 4+ (Aqp4+) 血管周围末端脚/血液相关 大脑中的血管。 hCD63-GFP+ 星形胶质细胞外泌体也可以在注射 LPS 的血清中检测到（但 非对照）Glast-CreER+CD63-GFPf/+ 小鼠。令人兴奋的是，“反应性”星形胶质细胞（RAE）分泌的外泌体 在体外和体内强烈激活 CD4+ 和 CD8+ T 细胞。根据之前的研究和我们的初步 根据结果​​，我们建议研究以下目标：1）确定中枢神经系统细胞类型特异性的病理流出 AD 模型中来自大脑的外泌体及其进入外周循环； 2) 确定AD-的抗原性 相关星形胶质细胞外泌体在体外和体内激活 T 细胞的作用。我们已经产生了大量的 初步数据支持我们的理由并证明拟议目标的可行性。我们将聘用 小鼠遗传学、病毒注射、免疫组织化学 (IHC) 分析和体内双光子成像、初级 培养、FACS 和生化方法来研究这两个目标。该项目的结果将 确定神经元或星形胶质细胞外泌体从大脑的流出变化以及这些外泌体进入 AD 模型中的外周循环。此外，我们目前的研究将调查T细胞如何应对“反应性” 星形胶质细胞外泌体。由于反应性星形胶质细胞在包括 AD 在内的神经退行性疾病中常见， 这将有可能揭示 T 细胞如何参与 AD 发病机制的新机制，并帮助定义特定的 大脑发出信号来激活 AD 中的 T 细胞，从而促进治疗的发展。