Myonuclear Epigenetics of Skeletal Muscle Mass Regulation with Age

骨骼肌质量随年龄调节的肌核表观遗传学

• 批准号: 9982169
• 负责人: Kevin Murach
• 金额: $ 9.87万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9982169
• 关键词: Address; Adult; Affect; Age; Aging; Atrophic; Biogenesis; Cell Nucleus; Cell Separation; Clinical; Cues; Custom; DNA; DNA Methylation; Data; Development; Enhancers; Epigenetic Process; Exercise; Fiber; Foundations; Functional disorder; Future; Genes; Genetic Transcription; Genome; Grant; Hindlimb Suspension; Human Genome; Hypermethylation; Hypertrophy; Intervention; Knowledge; Label; Learning; Life; Limb structure; Maps; Mediating; Memory; Mentors; Methylation; Mitotic; Modification; Mus; Muscle; Muscle Fibers; Muscle function; Muscular Atrophy; Nuclear; Phase; Phenotype; Plantaris muscle; Population; Protocols documentation; Quality of life; Regulation; Rejuvenation; Research; Research Personnel; Research Training; Ribosomal DNA; Ribosomal RNA; Ribosomes; Running; Science; Skeletal Muscle; Soleus Muscle; Stimulus; Techniques; Testing; Therapeutic; Time; Training; aged; base; bisulfite sequencing; career; combat; cost; dosage; epigenetic memory; epigenetic regulation; exercise training; experimental study; fall risk; genome wide methylation; improved; insight; loss of function; methylome; mortality; mouse genome; mouse model; muscle aging; muscle form; muscle hypertrophy; novel; reduced muscle mass; response; sedentary; skills; stressor; success; therapeutic target; tool; training opportunity; transcriptome

PROJECT SUMMARY/ABSTRACT Skeletal muscle mass declines with age and simultaneously loses the ability to adapt to stressors. Reduced muscle mass and function associated with aging ultimately leads to a loss of independence and mortality, costing billions of dollars to the US economy every year. Understanding what contributes to muscle mass loss with age and what mediates the ability to enhance muscle mass with exercise or alternative therapeutics is of critical importance for developing effective countermeasures. The study of epigenetics, and specifically DNA methylation status has become increasingly popular in recent years since this level of regulation heavily dictates what genes are expressed and for how long. Skeletal muscle is multi-nucleated and ~50% of nuclei in the muscle compartment are myonuclei. Little can be inferred about DNA methylation in muscle fibers without the ability to specifically isolate myonuclei. We recently developed a genetically modified mouse model for labeling skeletal muscle myonuclei and a workflow for purifying these labeled myonuclei for downstream epigenetic applications. We also developed a translatable and reversible murine model of progressive weighted wheel running (PoWeR) that elicits hypertrophy in muscles of different fiber type composition and function. Using these novel tools, the purpose of this proposal is to provide the first muscle type-specific insight into the epigenetic regulation of skeletal muscle mass with aging, and determine whether early life stimuli affect muscle adaptability later in life. I will profile myonuclear DNA using reduced representation bisulfite sequencing in order to explore global methylation status, and focus in on ribosomeal DNA (rDNA) methylation since ribosome biogenesis is strongly implicated in skeletal muscle mass regulation. In the mentored phase of the grant, I will learn the requisite epigenetic techniques for studying muscle mass regulation by evaluating myonuclear epigenetics during hypertrophy (PoWeR) and atrophy (hindlimb suspension). With these newly acquired skills, I will profile myonuclear DNA from oxidative and glycolytic muscles during the independent phase to provide a comprehensive epigenetic map of muscle aging. I will also PoWeR train mice early in life to determine whether previous hypertrophy affects adaptability to that same stimulus later in life with the aim of identifying epigenetic cues for improving muscle adaptability in old age. My global hypotheses are that hypertrophy will be associated with muscle type-specific global and rDNA hypomethylation, while unloading and aging will be characterized by muscle type-specific hypermethylation. I also hypothesize that early life exercise will be associated with rDNA hypomethylation later in life, which will associate with restored hypertrophic adaptability in old age. The experiments in this proposal will provide a foundation for the development of epigenetic-based therapeutics aimed at skeletal muscle rejuvenation with aging. Furthermore, the training opportunity afforded by this project will facilitate my success as an independent researcher focused on the epigenetics of muscle mass regulation during aging in skeletal muscle.

项目概要/摘要 骨骼肌质量随着年龄的增长而下降，同时失去适应压力的能力。减少 与衰老相关的肌肉质量和功能最终导致独立性的丧失和死亡， 每年给美国经济造成数十亿美元的损失。了解导致肌肉质量损失的因素 随着年龄的增长，以及通过运动或替代疗法增强肌肉质量的能力的调节因素 对于制定有效的对策至关重要。表观遗传学，特别是 DNA 的研究 近年来，甲基化状态变得越来越流行，因为这种水平的监管严重 决定了哪些基因被表达以及表达多长时间。骨骼肌是多核的，约 50% 的细胞核位于 肌肉室是肌核。如果不了解肌肉纤维中 DNA 甲基化的情况，我们几乎无法推断出 特异性分离肌核的能力。我们最近开发了一种转基因小鼠模型 标记骨骼肌肌核以及纯化这些标记肌核以供下游使用的工作流程 表观遗传学应用。我们还开发了一种可翻译和可逆的渐进性小鼠模型 负重轮跑 (PoWeR) 可引起不同纤维类型组成的肌肉肥大， 功能。使用这些新颖的工具，该提案的目的是提供第一个特定于肌肉类型的见解 研究骨骼肌质量随衰老的表观遗传调控，并确定早期生活刺激是否会影响 以后生活中的肌肉适应性。我将使用简化代表性亚硫酸氢盐测序来分析肌核 DNA 为了探索全球甲基化状态，并重点关注核糖体DNA（rDNA）甲基化 核糖体生物发生与骨骼肌质量调节密切相关。在指导阶段 授予，我将通过评估来学习研究肌肉质量调节所需的表观遗传技术 肥大（PoWeR）和萎缩（后肢悬吊）期间的肌核表观遗传学。有了这些新 获得技能后，我将在独立训练期间分析氧化肌和糖酵解肌的肌核 DNA 阶段提供肌肉衰老的全面表观遗传图谱。我还将在生命早期对小鼠进行 PoWeR 训练 确定先前的肥大是否会影响以后生活中对相同刺激的适应性，目的是 识别改善老年肌肉适应性的表观遗传线索。我的全球假设是 肥大与肌肉类型特异性整体和 rDNA 低甲基化有关，而卸载 衰老的特征是肌肉类型特异性的高甲基化。我还假设早年生活 运动将与晚年 rDNA 低甲基化相关，这将与恢复相关 老年适应性肥大。本提案中的实验将为 开发基于表观遗传学的疗法，旨在随着衰老而使骨骼肌恢复活力。此外， 该项目提供的培训机会将促进我作为一名独立研究员的成功 骨骼肌衰老过程中肌肉质量调节的表观遗传学。