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.

项目摘要/摘要 骨骼肌质量随着年龄的增长而下降，同时失去了适应压力源的能力。减少 肌肉质量和与衰老相关的功能最终导致独立性和死亡率丧失， 每年为美国经济造成数十亿美元。了解什么导致肌肉质量损失 随着年龄的增长以及介导的锻炼或替代治疗能力增强肌肉质量的能力是 对于发展有效的对策至关重要。表观遗传学的研究，特别是DNA 近年来，近年来，甲基化状况已变得越来越流行 决定表达的基因以及多长时间。骨骼肌是多核的，约有50％的核中的肌肉 肌肉舱是肌核。关于没有的肌肉纤维中的DNA甲基化几乎无法推断 特异性分离肌核的能力。我们最近开发了一种转基因的小鼠模型 标记骨骼肌肉肌肉肌和用于净化这些标记为下游的标记的工作流程 表观遗传应用。我们还开发了一种可翻译和可逆的渐进式鼠模型 加权车轮跑步（功率），引起不同纤维类型成分肌肉的肥大和 功能。使用这些新颖的工具，该提案的目的是提供第一个肌肉类型特定的见解 随着衰老的骨骼肌质量的表观遗传调节，并确定早期刺激是否影响 肌肉的适应能力以后。我将使用减少表示的Bisulfite测序来介绍肌核DNA 为了探索全局甲基化状态，并专注于核糖核DNA（rDNA）甲基化，因为 核糖体生物发生与骨骼肌质量调节密切相关。在指导阶段 格兰特，我将学习通过评估来研究肌肉质量调节的必要表观遗传技术 肥大（功率）和萎缩（后肢悬浮液）期间的肌核表观遗传学。与这些新的 获得的技能，我将在独立过程中介绍来自氧化和糖酵解肌肉的肌核DNA 提供肌肉衰老的全面表观遗传图的阶段。我还将在生命早期为老鼠动力训练 确定以前的肥大是否会影响以后生活中同一刺激的适应性 识别表观遗传提示，以改善老年肌肉适应能力。我的全球假设是 肥大将与肌肉类型特异性全局和rDNA降负荷有关 衰老将以肌肉类型特异性的高甲基化为特征。我也假设早期 运动将与rDNA后期的rdna降压剂有关，这将与恢复 肥厚的适应能力在老年。本提案中的实验将为 基于表观遗传学的治疗剂的开发旨在随着衰老而骨骼肌复兴。此外， 这个项目提供的培训机会将有助于我作为独立研究人员的成功 关于骨骼肌衰老期间肌肉质量调节的表观遗传学。