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).

概括 了解阿尔茨海默病 (AD) 与衰老相关的分子和细胞机制 降低风险和延长寿命的遗传变异是遗传转化的关键瓶颈 我们的建议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。 体内大多数富含胆固醇/脂质的器官因此，衰老/患病大脑中的组织损伤会产生大量的胆固醇/脂质。 大量富含胆固醇/脂质的细胞碎片（MΦ，如大脑中的小胶质细胞）是细胞类型。 专门致力于维持和恢复组织稳态，主要通过其以下能力：1）吞噬和 清除凋亡细胞和其他细胞碎片（胞吞作用），2) 协调先天免疫反应。 当受到富含胆固醇/脂质的细胞碎片的挑战时，MΦ 上调多个基因的表达 参与胆固醇/脂质代谢、胞吞作用和 AD。该基因表达谱经常被提及。 如 DAM/LAM（与疾病相关的小胶质细胞/脂质相关的巨噬细胞）。 DAM/LAM 基因是载脂蛋白 E (APOE)，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。 我们和其他人表明，在全基因组关联中发现了常见的非编码 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 AD 病因学中的基因表达调控（以及 SPI1/PU.1 等转录因子）的通路分析。 这些等位基因还涉及胆固醇代谢、吞噬作用和先天免疫，同样是罕见的编码。 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，并具有关键作用 我们的主要假设是 AD/衰老相关的遗传因素。 变异通过影响表达或结构从而影响相关基因的活性来调节风险/寿命 吞噬清除胆固醇/富含脂质的细胞碎片，从而损害小胶质细胞维持大脑的能力 我们的方法是使用同基因的人类 iPSC 衍生的小胶质细胞。 (iMGL) 携带 AD/衰老相关基因型和基因修饰，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）和体内（小鼠大脑异种移植物43）。 基因型（目标 1）、BHLHE40/41 和 NR1H2/3 转录因子（目标 2）及其治疗相互作用 （目标 3）。