Reversing age-related epigenetic changes and characterizing microglia heterogeneity in obesity and aging

项目摘要 神经炎是大脑老化的标志，可能会导致功能下降和神经退行性变 疾病。作为大脑的常驻巨噬细胞，小胶质细胞对大脑的维护至关重要，但一直以来 随着年龄的增长，表现出促炎症的表型。拟议中的研究将检验这一角色 小胶质细胞特异的表观遗传机制在衰老中的作用，并确定肥胖和衰老相互作用的影响 关于小胶质细胞表型的异质性。我们将确定异常的与年龄相关的小胶质细胞特异性 表观遗传模式可以通过异时血浆方法逆转。此外，我们将确定如何 小胶质细胞亚群在单细胞水平上随年龄和肥胖而不同，对脂滴有特殊的兴趣。 积聚小胶质细胞(LDAM)。培训的目标是：1)获得扎实的知识和基础 在抗衰老和肥胖的动物和营养模型中2)获得技术和实践经验 不同组学方法在特定海马细胞和单细胞水平上所需的生物信息学技能 3)应用这些技能来实现本提案中概述的研究目标，并5)获得经验和改进 口头和陈述技能、手稿和赠款写作，以实现向独立的过渡。在目标1中，我们 假设老年小鼠暴露在年轻血浆中将逆转与年龄相关的小胶质细胞特异性DNA 为恢复“年轻”的表观基因组模式而进行的修改。这是基于这样一个前提，即DNA修饰 小胶质细胞功能的实现所需的各种表型的关键调节因子 衰老。我们将确定将年轻小鼠的血浆注入老年小鼠是否可以逆转与年龄相关的 CX3CR1：NuTRAP小鼠小胶质细胞特异性海马区表观遗传和转录变化 基因组氧化亚硫酸氢盐测序(WGoxBS)和RNA测序。这些研究将确定 适合返老还童干预的特定基因组位置，并作为未来表观基因组的靶点 编辑研究。在目标2中，我们将确定肥胖和衰老的相互作用如何影响小胶质细胞。 异质性。我们假设高脂饮食会导致病理性LDAM的扩张，从而导致 小胶质细胞功能，这种功能可以通过晚年的卡路里限制来逆转。我们将使用单细胞转录 分析、批量转录和小胶质细胞功能分析(吞噬细胞摄取和细胞因子/趋化因子 分析)以确定饮食诱导的肥胖小鼠小胶质细胞亚群随年龄的变化。此外, 我们将确定在饮食诱导的肥胖小鼠12个月开始限制卡路里是否可以减轻 肥胖对小胶质细胞异质性的影响。这将有助于确定对小胶质细胞的机械性见解。 异质性、低密度脂蛋白和肥胖相关的神经炎症。总体而言，培训目标和目的将 提供所需的技能和专业知识，从事专注于开发抗衰老的研究事业 干预措施。

Project Summary Neuroinflammation is a hallmark of brain aging that may contribute to declines in function and neurodegenerative diseases. As the resident macrophage of the brain, microglial are crucial to brain maintenance but have been demonstrated to take on pro-inflammatory phenotypes with aging. The proposed research will examine the role of microglia-specific epigenetic mechanisms in aging and determine the effects of obesity and aging interactions on microglia phenotypic heterogeneity. We will determine whether aberrant age-related microglia-specific epigenetic patterns can be reversed by heterochronic plasma approaches. Additionally, we will determine how microglia subpopulations differ with age and obesity at a single-cell level with special interests in lipid-droplet- accumulating microglia (LDAM). The goals of the training are to: 1) obtain a strong knowledge and foundation in animal and nutritional models of anti-aging and obesity 2) gain hands-on experience in technologies and bioinformatic skills needed for various omics approaches in specific hippocampal cells and at a single-cell level 3) apply these skills to achieve the research aims outlined in this proposal and 5) gain experience and improve oral and presentation skills, manuscript and grant writing to enable a transition to independence. In Aim 1, we hypothesize that exposure of old mice to young plasma will reverse age-related microglia-specific DNA modifications to restore ‘youthful’ epigenomic patterns. This is based on the premise that DNA modifications are key regulators of the diverse phenotypes required for the fulfillment of microglia functions which are disrupted in aging. We will determine whether the administration of plasma from young into old mice can reverse age-related microglial-specific hippocampal epigenetic and transcriptomic changes in Cx3cr1:NuTRAP mice using whole genome oxidative bisulfite sequencing (WGoxBS) and RNA sequencing, respectively. These studies will identify specific genomic sites amenable to the rejuvenating interventions and serve as targets for future epigenome editing studies. In Aim 2, we will determine how the interaction of obesity and aging affect microglia heterogeneity. We hypothesize that high-fat diet leads to expansion of pathological LDAM resulting in impaired microglial function, which can be reversed by late-life calorie restriction. We will use single-cell transcriptomic analysis, bulk transcriptomics and microglia functional assays (phagocytic uptake and cytokine/chemokine analysis) to determine changes in microglia subpopulations in dietary-induced obese mice with age. In addition, we will determine whether starting calorie restriction at 12 months in dietary-induced obese mice can mitigate the effects of obesity on microglia heterogeneity. This will help identify mechanistic insights into microglia heterogeneity, LDAM and obesity-associated neuroinflammation. In total, the training goals and objectives will provide the needed skills and expertise to pursue a research career focused on developing anti-aging interventions.