APOE effects on glial lipid metabolism and 25-hydroxycholesterol: Effects on aging and AD-related pathology

APOE 对神经胶质脂质代谢和 25-羟基胆固醇的影响：对衰老和 AD 相关病理的影响

• 批准号: 10667466
• 负责人: DAVID M. HOLTZMAN
• 金额: $ 53.02万
• 依托单位: MAYO CLINIC JACKSONVILLE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10667466
• 关键词: 25-hydroxycholesterol; Affect; Age; Aging; Agonist; Alzheimer' s Disease; Amyloid beta-Protein; Amyloid deposition; Apolipoprotein E; Astrocytes; Biochemical; Bioinformatics; Biological Markers; Biology; Brain; Brain region; Cells; Cholesterol; Cholesterol Esters; Cholesterol Homeostasis; Coculture Techniques; Collaborations; Data; Defect; Demyelinations; E protein; Gene Expression; Genotype; Histologic; Human; Immune; Immunomodulators; In Vitro; Inflammasome; Inflammation; Inflammatory Response; Injections; Innate Immune Response; Knock-in; Knock-in Mouse; Knockout Mice; Link; Lipids; Lipoproteins; Literature; Mass Spectrum Analysis; Measures; Mediating; Microglia; Mixed Function Oxygenases; Modeling; Mus; Nerve Degeneration; Neuroglia; Neurons; Pathogenesis; Pathology; Phenotype; Play; Process; Production; Property; Protein Isoforms; Proteomics; Regulation; Role; Signal Transduction; Source; Sterols; Stimulus; Structure; Tauopathies; Variant; Work; abeta deposition; age related; cytokine; density; glial activation; immunoregulation; improved; in vivo; induced pluripotent stem cell; lipid metabolism; lipidomics; metabolomics; neuropathology; neurotoxicity; particle; remyelination; response; reverse cholesterol transport; sex; tau Proteins

PROJECT SUMMARY (APOE U19: PROJECT 2) Project 2 seeks to improve understanding of how apolipoprotein E (apoE) isoforms influence glial lipid metabolism and inflammatory responses underlying immune-mediated damage in the brain in Alzheimer’s disease (AD) and aging-related pathologies. Evidence indicates that the apoE protein not only affects Aβ deposition and structure, it strongly influences microglial-activation, Aβ-induced neuritic dystrophy, and tau- mediated neurodegeneration. ApoE produced by both astrocytes and microglia plays an important role in these effects, and microglia are critical effectors of neurodegeneration. In alignment with the ApoE Cascade Hypothesis of this U19, we anticipate that structural differences and related biochemical properties among the apoE isoforms are likely to mediate the differential effects of apoE on the brain’s innate immune response. Factors such as lipid metabolism and sterol processing, can influence microglial reactivity in ways that are relevant to AD pathogenesis. Recent evidence indicates that apoE and aging critically influence the process of cholesterol and lipid clearance in the brain, specifically in microglia. Accumulation of lipid debris in microglia under different conditions is linked with microglial activation and inflammasome-mediated damage. There is also literature and we have preliminary data that 25-hydroxycholesterol (25HC), a known oxysterol immunomodulator, is produced in the brain by microglia and can modulate cholesterol metabolism as well as the microglial cytokine response in an apoE isoform-dependent manner in vitro. These data lead us to hypothesize that apoE-dependent regulation and clearance of cholesterol esters and other lipids specifically in microglia regulates the microglial inflammatory response in aging and AD. We further hypothesize that this microglial response including 25HC production impacts Aβ-induced local damage, Aβ- induced tau spreading, and tau-mediated neurodegeneration in an apoE, age, and sex-dependent fashion. We propose these aims: Aim 1: Determine the effects of apoE and apoE isoforms on cholesterol, cholesterol esters, and other lipids in astrocytes and microglia during aging, in the setting of Aβ and tau pathology, and with LXR agonist stimulation. Aim 2: Assess the effects of the immunomodulatory oxysterol, 25- hydroxycholesterol (25HC) on Aβ-mediated tau-spreading, tau-mediated neurodegeneration, and age-related brain phenotypes and how these are modified by apoE. Aim 3: Assess the effect of apoE isoform on the lipidomic profile of astrocytes, microglia, and secreted apoE-containing lipoproteins as well as the mechanistic relationship between lipid droplet formation, apoE signaling, and inflammation in vitro. We will also assess the mechanism of the effects of ch25h on apoE-mediated neurodegeneration in vitro. Impact/Integration: Project 2 will work closely with Projects 1, 3, 5, Core B, Core D, Core E, Core F, and Core G on production, purification, and characterization of apoE particles and lipids from mouse glia in vitro and in vivo and iPSC derived glia in vitro. Histological analysis in Project 2 will be done with the Neuropathology Core (Core C).

项目概要（APOE U19：项目2） 项目2旨在提高对载脂蛋白E（apoE）亚型如何影响神经胶质脂质的理解 阿尔茨海默病患者脑内免疫介导损伤的基础代谢和炎症反应 疾病（AD）和衰老相关的病理。有证据表明，apoE蛋白不仅影响Aβ， 沉积和结构，它强烈影响小胶质细胞活化，Aβ诱导的神经炎性营养不良，和tau蛋白， 介导的神经变性。由星形胶质细胞和小胶质细胞产生的ApoE在细胞凋亡中起重要作用。 这些效应和小胶质细胞是神经变性的关键效应物。与ApoE级联相一致 假设这个U19，我们预计，结构差异和相关的生化性质之间的 apoE同种型可能介导apoE对脑先天免疫应答的不同作用。 脂质代谢和甾醇加工等因素可以影响小胶质细胞的反应性， 与AD发病机制有关。最近的证据表明，apoE和衰老严重影响的过程中， 胆固醇和脂质清除在大脑中，特别是在小胶质细胞。脂质碎片在小胶质细胞中的积聚 在不同的条件下，与小胶质细胞活化和炎性小体介导的损伤有关。有 也有文献，我们有初步的数据，25-羟基胆固醇（25 HC），一种已知的氧化甾醇 免疫调节剂，由小胶质细胞在大脑中产生，可以调节胆固醇代谢以及 体外apoE亚型依赖性的小胶质细胞细胞因子反应。这些数据使我们 假设胆固醇酯和其它脂质apoE依赖性调节和清除 特别是在小胶质细胞中调节衰老和AD中的小胶质细胞炎症反应。我们进一步 假设这种包括25 HC产生的小胶质细胞反应影响Aβ诱导的局部损伤， 诱导tau蛋白扩散，和tau蛋白介导的神经退行性变，在apoE，年龄和性别依赖性的方式。我们 目的1：确定apoE及其亚型对胆固醇，胆固醇， 酯和其他脂质在老化过程中的星形胶质细胞和小胶质细胞中，在Aβ和tau病理学的背景下， 用LXR激动剂刺激。目的2：评估免疫调节剂氧固醇25- 羟基胆固醇（25 HC）对Aβ介导的tau扩散、tau介导的神经变性和年龄相关的 大脑表型以及这些表型如何被apoE修饰。目的3：评估apoE亚型对细胞凋亡的影响。 星形胶质细胞、小胶质细胞和分泌的含apoE的脂蛋白的脂质组学特征以及 脂滴形成、apoE信号传导和体外炎症之间的关系。我们亦会评估 ch 25 h对apoE介导的体外神经变性的作用机制。影响/整合：项目 2将与项目1、3、5、核心B、核心D、核心E、核心F和核心G在生产方面密切合作， 体外和体内来自小鼠神经胶质细胞和iPSC的apoE颗粒和脂质的纯化和表征 体外诱导胶质细胞。项目2中的组织学分析将使用神经病理学核心（核心C）进行。