Role of skeletal muscle mitophagy in healthy aging

骨骼肌线粒体自噬在健康衰老中的作用

• 批准号: 9761948
• 负责人: Josh C Drake
• 金额: $ 10.33万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2019-12-24
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9761948
• 关键词: Age; Aging; Animals; Autophagocytosis; Biosensor; Confocal Microscopy; Development; Disease; Elderly; Electric Stimulation; Excision; Exercise; Fostering; Foundations; Functional disorder; Gastrocnemius Muscle; Geroscience; Holoenzymes; Human; Immunohistochemistry; Impairment; In Vitro; Intervention; Knock-out; Knockout Mice; Learning; Longevity; Maintenance; Mediating; Mentors; Metabolic; Microscopy; Mitochondria; Mitochondrial Proteins; Mus; Muscle; Muscle Fibers; Muscle Mitochondria; Phase; Phosphorylation; Phosphotransferases; Photosensitization; Plantaris muscle; Preparation; Proteins; Proteomics; Quality Control; RNA interference screen; Regulation; Reporting; Research; Resolution; Reticulum; Role; Sarcolemma; Signal Transduction; Skeletal Muscle; Somatic Gene Therapy; Stains; Stress; Testing; Tissues; Training; Wild Type Mouse; Work; age related; career development; confocal imaging; effective intervention; flexor digitorum brevis; healthy aging; imaging approach; improved; in vivo; insight; irradiation; mimetics; muscle aging; novel; programs; recruit; response; skills; tibialis anterior muscle; two photon microscopy; two-photon

Project Summary Mitochondrial quality in skeletal muscle progressively declines with advancing age, leading to tissue dysfunction and disease. Several lines of evidence suggest poor mitochondrial quality in skeletal muscle of old animals and humans is due in large part to an impaired or insufficient capacity to degrade damaged/dysfunctional mitochondria via mitophagy. Exercise promotes mitochondrial quality leading to healthy aging but the underlying mechanisms and how they differ with age is not well defined, particularly in regards to mitophagy, restraining development of effective interventions. Building upon my previous work demonstrating that exercise does indeed promote mitophagy in skeletal muscle but only of a small fraction of the total mitochondrial reticulum, I show here evidence of an Ampk-dependent mechanism that may distinguish damaged vs. healthy regions of the mitochondrial reticulum that is lost with age. Additionally, I show that key downstream mitophagy-related factors that are recruited to mitochondria in skeletal muscle with exercise are required for mitochondrial quality and healthy aging in d. melanogaster. The proposed research tests the hypothesis that recognition of damaged regions of the mitochondrial reticulum in response to exercise is impaired in skeletal muscle of old mice, blunting local recruitment of key mitophagy proteins, leading to poor mitochondrial quality. These studies will provide insight into novel regulation of skeletal muscle mitophagy in response to exercise and lay a foundation for the development of targeted interventions to promote mitochondrial quality in skeletal muscle for improved tissue function and healthy aging. During the mentored phase, I will employ state-of-the-art two-photon microscopy to perform intravital and ex vivo fluorescent lifetime microscopy of Ampk activity on mitochondria in skeletal muscle of young and old mice to determine the age-dependent, localized response of Ampk to sustained contraction and mitochondrial damage. Also, I will continue my professional and scientific development in preparation for the independent phase with continuous guidance from my mentoring committee. During the independent phase, I will employ co-somatic gene transfer in skeletal muscle of young and old wild-type mice as well as skeletal muscle-specific, conditional Ulk1 knock-out mice to determine the age-dependent regulation for the recruitment of downstream mitophagy-related factors to mitochondria in skeletal muscle in response to exercise. Also, I will develop novel phospho-mimetic constructs to constitutively activate or inhibit mitophagy-related factors Atg9 and Atg2 in young and old mouse skeletal muscle and investigate their necessity and sufficiency for the breakdown of mitochondrial proteins and maintenance of mitochondrial quality, via state-of-the-art high resolution proteomic and confocal imaging approaches. Collectively, these studies and career development activities will foster my continued scientific and professional training, leading to a successful independent, academic research program.

项目摘要 骨骼肌的线粒体质量随着年龄的增长而逐渐下降，导致组织功能障碍 和疾病。几条证据表明，在旧动物的骨骼肌和 人类在很大程度上是由于降解损伤/功能失调的能力受损或不足的能力 线粒体通过线粒体。锻炼可促进线粒体质量，导致健康衰老，但基础 机制及其年龄的差异并不是很好的定义，尤其是在线粒体上的限制方面 开发有效的干预措施。在我以前的工作的基础上证明了锻炼确实确实 在骨骼肌中促进线粒体，但仅占总线粒体网状的一小部分，我在这里显示 AMPK依赖机制的证据，该机制可能会区分受损与健康区域 线粒体网状会随着年龄的增长而丢失。此外，我显示了下游线粒体相关因素的关键因素 通过运动质量和 健康衰老d。 Melanogaster。拟议的研究检验了以下假设： 线粒体网状响应运动的区域在旧小鼠的骨骼肌中受损，钝 局部招募关键线粒体蛋白，导致线粒体质量差。这些研究将提供 洞察骨骼肌线粒体的新型调节，以响应运动，并为 开发有针对性的干预措施，以促进骨骼肌的线粒体质量以改善组织 功能和健康衰老。在指导阶段，我将采用最新的两光子显微镜 在骨骼肌中对线粒体的AMPK活性进行插入术和离体荧光寿命显微镜 小鼠和老鼠以确定AMPK对持续收缩的年龄依赖性的局部反应 和线粒体损伤。另外，我将继续我的专业和科学发展，以准备 我的指导委员会不断指导的独立阶段。在独立阶段， 我将在年轻和老野生型小鼠的骨骼肌以及骨骼的骨骼肌中使用共同基因转移 肌肉特异性，有条件的ULK1敲除小鼠，以确定招募年龄的调节 骨骼肌肉中线粒体的下游线粒体相关因素的响应。另外，我会的 开发新型的磷酸仿真构建体以组成性激活或抑制线粒体相关因子ATG9和 年轻的老鼠骨骼肌的ATG2，并研究其故障的必要性和足够性 线粒体蛋白质和线粒体质量的维护，通过最先进的高分辨率蛋白质组学 和共聚焦成像方法。总的来说，这些研究和职业发展活动将促进我的 持续的科学和专业培训，导致成功的独立学术研究计划。