Investigating the effects of APOE and APOE-related AD risk genes on human microglia activity and lipid metabolism in aging and disease

研究 APOE 和 APOE 相关 AD 风险基因对衰老和疾病过程中人类小胶质细胞活性和脂质代谢的影响

• 批准号: 10900992
• 负责人: EDOARDO MARCORA
• 金额: $ 74.58万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10900992
• 关键词: 3-Dimensional; Address; Affect; Aging; Agonist; Alleles; Alzheimer' s Disease; Alzheimer' s disease risk; Amyloid deposition; Apolipoprotein E; Apoptotic; Biological; Biological Process; Brain; Brain Diseases; Cell physiology; Cells; Cellular Stress; Cholesterol; Cholesterol Homeostasis; Code; Data; Disease; Disease associated microglia; Drug Targeting; Enhancers; Etiology; Foundations; Functional disorder; Gene Expression; Gene Expression Profile; Gene Expression Regulation; Gene Modified; Genes; Genetic; Genotype; Goals; Homeostasis; Human; Human Genetics; Immune; Impairment; In Vitro; Inflammatory Response; Innate Immune Response; Innate Immune System; Investigation; Knock-out; Link; Lipids; Longevity; Macrophage; Maintenance; Metabolic; Microglia; Molecular; Mus; Mutation; Natural Immunity; Nuclear Receptors; Organ; PLCG2 gene; Pathogenesis; Pathway Analysis; Pathway interactions; Phagocytes; Phagocytosis; Phenotype; Preclinical Drug Development; Primates; Public Health; Publications; RXR; Research; Risk; Role; SPI1 gene; Stress; Structure; TREM2 gene; Testing; Therapeutic; Tissues; Transcription Factor 3; Translational Repression; Untranslated RNA; Xenograft procedure; aged; brain cell; brain tissue; cell type; chronic demyelination; gene function; genetic variant; genome wide association study; genome-wide analysis; healthy aging; in vivo; induced pluripotent stem cell; lipid metabolism; lipidomics; overexpression; pharmacologic; restoration; risk variant; small molecule; therapeutic development; therapeutic evaluation; therapeutically effective; three dimensional cell culture; transcription factor; transcriptomics; translational genetics

SUMMARY Understanding the molecular and cellular mechanisms linking Alzheimer’s disease (AD) and aging-associated genetic variants to reduced risk and increased longevity is a critical bottleneck for the translation of genetic findings into effective therapeutics. Our proposal aims to fill this gap by focusing on biological processes (cholesterol/lipid clearance), cell types (microglia), and genes implicated by human genetics. The brain is the most cholesterol/lipid-rich organ in the body. Hence, tissue damage in the aged/diseased brain produces large amounts of cholesterol/lipid-rich cellular debris. Macrophages (MΦ, like microglia in the brain) are cell types specialized in maintenance and restoration of tissue homeostasis, mainly via their ability to 1) phagocytose and clear apoptotic cells and other cellular debris (efferocytosis) and 2) orchestrate an innate immune response. When challenged with cholesterol/lipid-rich cellular debris, MΦ upregulate the expression of several genes involved in cholesterol/lipid metabolism, efferocytosis and AD. This gene expression profile is often referred to as DAM/LAM (for disease-associated microglia/ lipid-associated macrophages). The most upregulated DAM/LAM gene is Apolipoprotein E (APOE), a major gene for cholesterol metabolism and AD, and one of very few genes associated with longevity. We and others showed that common non-coding AD risk alleles identified in genome-wide association studies (GWAS) are enriched in MΦ-specific enhancers, strongly implicating these cell types and MΦ-specific gene expression regulation (and transcription factors like SPI1/PU.1) in the etiology of AD. Pathway analysis of these alleles also implicated cholesterol metabolism, phagocytosis, and innate immunity. Similarly, rare coding AD risk alleles impact the structure/function of genes highly or specifically expressed in MΦ and with critical roles in efferocytosis (e.g., TREM2, ABCA7, ABI3). Our main hypothesis is that AD/aging-associated genetic variants modulate risk/longevity by affecting expression or structure and thus activity of genes involved in phagocytic clearance of cholesterol/lipid-rich cellular debris, thereby impairing microglia ability to maintain brain tissue homeostasis during aging and disease. Our approach is to use isogenic human iPSC-derived microglia (iMGL) carrying AD/aging-associated genotypes and gene modifications to assess their impact on microglial lipid metabolism, gene expression, and functional roles, at baseline and in aging/disease-relevant contexts, both in vitro (2D and 3D cultures) and in vivo (mouse brain xenografts43). In particular, we will focus on APOE genotypes (Aim 1), BHLHE40/41 and NR1H2/3 transcription factors (Aim 2), and their therapeutic interactions (Aim 3).

总结 了解阿尔茨海默病（AD）与衰老相关的分子和细胞机制 基因变异降低风险和增加寿命是基因翻译的关键瓶颈。 发现有效的治疗方法。我们的提案旨在通过关注生物过程来填补这一空白 （胆固醇/脂质清除）、细胞类型（小胶质细胞）和与人类遗传学有关的基因。大脑是 体内胆固醇/脂质最丰富的器官。因此，老年/患病大脑中的组织损伤产生大的 大量的胆固醇/富含脂质的细胞碎片。巨噬细胞（MΦ，就像大脑中的小胶质细胞）是细胞类型 专门维持和恢复组织稳态，主要通过它们的能力：1）吞噬， 清除凋亡细胞和其它细胞碎片（红细胞增多症）和2）协调先天性免疫应答。 当用胆固醇/富含脂质的细胞碎片攻击时，MΦ上调几个基因的表达 参与胆固醇/脂质代谢、红细胞增多症和AD。这种基因表达谱通常被称为 作为DAM/LAM（用于疾病相关小胶质细胞/脂质相关巨噬细胞）。上调最多的 DAM/LAM基因是载脂蛋白E（Apolipoprotein E，APOE），其是胆固醇代谢和AD的主要基因，也是非常重要的基因之一。 与长寿相关的基因很少。 我们和其他研究表明，在全基因组关联中鉴定的常见非编码AD风险等位基因 研究（GWAS）富含MΦ特异性增强子，强烈暗示这些细胞类型和MΦ特异性增强子。 基因表达调控（和转录因子如SPI 1/PU.1）在AD病因学中的作用。途径分析 这些等位基因还涉及胆固醇代谢、吞噬作用和先天免疫。类似地， AD风险等位基因影响MΦ中高度或特异性表达的基因的结构/功能， 在红细胞增多症中的作用（例如，TREM2、ABCA 7、ABI 3）。我们的主要假设是，AD/衰老相关的遗传 变异体通过影响参与的基因的表达或结构，从而调节风险/寿命， 吞噬细胞清除胆固醇/富含脂质的细胞碎片，从而损害小胶质细胞维持脑功能的能力 在衰老和疾病期间的组织内稳态。我们的方法是使用同基因人类iPSC衍生的小胶质细胞， 携带AD/衰老相关基因型和基因修饰的iMGL，以评估其对小胶质细胞的影响。 基线和衰老/疾病相关背景下的脂质代谢、基因表达和功能作用， 体外（2D和3D培养物）和体内（小鼠脑异种移植物43）。特别是，我们将重点关注APOE 基因型（Aim 1）、BHLHE 40/41和NR 1H 2/3转录因子（Aim 2）及其治疗相互作用 (Aim（3）第三章。