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.

摘要 阿尔茨海默病（AD）仍然是我们社会中最未满足的医学挑战之一。在AD中， 神经炎症在AD的发病机制中起着重要作用， 细胞外淀粉样蛋白斑和基于过度磷酸化tau的神经元缠结。的作用虽然 先天免疫，特别是以小胶质细胞为代表的先天免疫，在AD中已经得到了很好的证实，但对它的了解还远远不够， 建立了关于T或B细胞介导的获得性免疫是否以及如何参与AD发病机制的研究。 特别是，是否有脑特异性抗原和AD特异性抗原激活适应性免疫，以及这些抗原如何激活适应性免疫。 抗原向外周的迁移仍有待研究。外泌体（大小40-100 nm），一种主要类型的分泌型 细胞外囊泡（EV）来源于管腔内囊泡（ILV），所述管腔内囊泡（ILV）从早期的细胞外囊泡（EV）向内出芽。 内体区室，并在成熟过程中从多囊泡体（MVB）释放。 核内体从各种CNS细胞类型分泌的EV和外泌体已经成为一种新的和重要的免疫调节剂。 细胞间通路。外泌体介导的分泌也与起始和繁殖有关 在AD中。尽管从各种外周细胞类型特别是免疫和肿瘤细胞分泌的外泌体触发了 关于CNS衍生的外泌体的免疫应答，CNS衍生的外泌体是否以及如何具有免疫原性仍然未被探索。 通过使用我们最近产生的细胞类型特异性ILV/外泌体报告基因（hCD 63-GFPf/f）小鼠，我们 显示星形胶质细胞来源的外泌体与水通道蛋白4+（Aqp 4+）血管周围末端足/血液相关， 大脑中的血管hCD 63-GFP+星形胶质细胞外泌体也可以在注射LPS的小鼠的血清中检测到（但 非对照）Glast-CreER+ CD 63-GFP f/+小鼠。令人兴奋的是，从“反应性”星形胶质细胞（RAEs）分泌的外泌体 在体外和体内强烈活化CD 4+和CD 8 + T细胞。根据以前的研究和我们的初步研究， 结果，我们建议调查以下目的：1）确定CNS细胞类型特异性的病理性流出 在AD模型中，来自脑的外来体及其进入外周循环; 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活化T细胞。我们已经产生了大量的 初步数据，以支持我们的理由，并证明拟议目标的可行性。我们会委聘 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，主要 培养，流式细胞仪和生物化学方法来研究这两个目标。该项目的成果将 确定神经元或星形胶质细胞外泌体从脑的流出变化以及这些外泌体进入脑内的能力。 AD模型的外周循环。此外，我们目前的研究将探讨T细胞如何对“反应性” 星形胶质细胞外泌体由于反应性星形胶质细胞通常在包括AD在内的神经退行性疾病中观察到， 这将潜在地揭示T细胞如何参与AD发病机制的新机制， 大脑信号激活AD中的T细胞，随后促进治疗开发。