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: 10685315
• 负责人: ALEXEI DEGTEREV
• 金额: $ 89.86万
• 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/10685315
• 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 Vessels; Brain; CD8-Positive T-Lymphocytes; Cells; Cerebrovascular system; Circulation; Clonality; Data; Detection; Disease; Early Endosome; 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; 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 阿尔茨海默氏病（AD）仍然是我们社会中最未满足的医疗挑战之一。在广告中， 神经炎症已被越来越多地被认为在AD的发病机理中起着核心作用，此外 细胞外淀粉样斑块和高磷酸化的基于TAU的神经原纤维缠结。虽然角色 尤其是小胶质细胞代表的先天免疫力在广告中已经建立了良好的理解和理解和 建立了关于T或B细胞介导的适应性免疫学如何参与AD发病机理的知识。 特别是，是否有脑和广告特异性抗原激活适应性免疫学以及如何激活这些抗原 抗原前往外围的抗原仍有待研究。外泌体（40-100 nm尺寸），一种主要的分泌类型 细胞外蔬菜（EV）是从内部蔬菜（ILV）衍生而来的，这些蔬菜是从早期开始的 内体隔室，并在成熟期间从多个囊泡体（MVB）释放 内体。来自各种中枢神经系统细胞类型分泌的电动汽车和外泌体已成为一种新颖而重要的 细胞间途径。外泌体介导的分泌也暗示了启动和传播 在广告中。尽管外围细胞类型分泌的外泌体，特别是免疫细胞和肿瘤细胞 免疫反应，CNS衍生的外泌体是否是免疫原性的，仍然是出乎意料的。 通过采用细胞类型的特异性ILV/外泌体报告基因（HCD63-GFPF/F）小鼠，我们 表明星形胶质细胞衍生的外泌体与水通道蛋白4+（AQP4+）周围末端/血液有关 大脑中的血管。也可以在注射LPS的血清中检测到HCD63-GFP+星形胶质细胞外泌体（但 无法控制）Glast-Creer+ CD63-GFPF/+小鼠。令人兴奋的是，从“反应性”星形胶质体（RAES）分泌的外泌体 在体外和体内强烈激活CD4+和CD8+ T细胞。基于以前的研究和我们的初步 结果，我们建议研究以下目的：1）确定CNS细胞类型特异性的病理外排 大脑的外泌体及其进入AD模型中的外周循环； 2）确定AD的抗原性 相关的星形胶质细胞外泌体在体外和体内激活T细胞。我们已经产生了大量 初步数据以支持我们的理由并证明对拟议目标的可行性。我们将雇用 小鼠遗传学，病毒注射，免疫组织化学（IHC）分析和体内两光子成像，原代 培养，FACS和生化方法来研究这两个目标。这个项目的结果将 确定来自大脑的神经元或星形胶质外泌体的外流变化以及这些外泌体进入 广告模型中的外围循环。此外，我们当前的研究将研究T细胞对“反应性”的反应 星形胶质外泌体。由于反应性星形胶质细胞通常在神经退行性疾病中观察到，包括AD， 这可能会揭示新机制如何参与AD发病机理，并有助于定义特定 大脑信号激活AD中的T细胞，随后支持治疗性发育。