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The role of satellite cells in skeletal muscle hypertrophy with aging

卫星细胞在衰老过程中骨骼肌肥大中的作用

基本信息

批准号：
10295407
负责人：
JOHN Joseph MCCARTHY
金额：
$ 35.71万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-15 至 2026-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10295407
关键词：
Ablation Adult Affect Age Aging Cell Communication Cell Nucleus Cell fusion Cells Characteristics Chronic Clinical Collagen Communication Deterioration Doxycycline Elderly Endothelial Cells Exercise Extracellular Matrix Female Fibroblasts Fibrosis Foundations Gene Expression Genes Genetic Transcription Grant Growth Human Hypertrophy Immunohistochemistry Impairment In Vitro Label Mechanics Messenger RNA MicroRNAs Modeling Molecular Mononuclear Morbidity - disease rate Mus Muscle Muscle satellite cell Muscular Atrophy Natural regeneration Output Phenocopy Plantaris muscle Population Population Dynamics Process Production Quality of life Reporter Reporting Rodent Role Skeletal Muscle Stimulus Systemic disease Tamoxifen Testing Therapeutic Therapeutic Uses Time Transcript Wasting Syndrome age related aged base cell age extracellular vesicles human old age (65+)in vivo intercellular communication interest male mortality mouse model muscle aging muscle form muscle hypertrophy novel patient population physical inactivity prevent progenitor response sarcopenia satellite cell single-cell RNA sequencing skeletal muscle growth skeletal muscle wasting stem cells transcriptome transcriptome sequencing young adult

项目摘要

Project Summary The loss of skeletal muscle mass with age is of clinical importance because it is associated with increased morbidity and mortality, as well as a marked deterioration in the quality of life. There is also a heightened interest in the identification of cellular and molecular mechanisms responsible for the lack of an anabolic response of aged muscle to hypertrophic stimuli. The use of satellite cells to treat loss of skeletal muscle mass is considered a promising therapeutic strategy given their stem cell characteristics and essential role in post- natal muscle growth and regeneration. The results of our studies have prompted us to perform mechanistic analyses of both of the well-known function of satellite cells; fusion to myofibers to provide additional nuclei for hypertrophic growth, to other functional consequences of satellite cell expansion that occurs in response to various exogenous stimuli such as exercise, as the increase in satellite cell abundance in response to mechanical overload far exceeds myonuclear accretion associated with increased myofiber size. We reported satellite cells were necessary for optimal long-term hypertrophic growth of skeletal muscle by regulating the extracellular matrix. Activated satellite cells repressed fibroblast collagen production via extracellular vesicle (EV) delivery of miR-206, revealing a previously unrecognized function of satellite cells, in addition to providing a mechanism through which satellite cells communicate with other cells within muscle. We now have in vivo single-cell (sc)RNA-seq evidence from Pax7-tdT reporter mice of a satellite cell intercellular communication network in which satellite cells communicate with FAPs/fibrogenic cells and endothelial cells during hypertrophic growth. Aim 1 will test the hypothesis that aging negatively impacts this communication network inhibiting proper remodeling of the extracellular matrix thereby inhibiting hypertrophy. We have also developed a novel mouse model that allows us to simultaneously deplete satellite cells and label resident myonuclei, Aim 2 will use this model and single-myonuclear (smn)RNA-seq to characterize age-dependent changes in the resident myonuclear transcriptome and identify mechanisms that enable short term hypertrophy in the absence of satellite cells in adult mice, which is lost in old age. Aim 3 will use an additional newly developed reporter mouse that enables specific and stable labeling of satellite cell nuclei to determine how aging alters the satellite cell-derived myonuclear transcriptome in response to a hypertrophic stimulus. We hypothesize that in aged muscle, satellite cell-derived myonuclei have altered transcriptional output that does not promote a hypertrophic response, and that impaired fusion of satellite cells or defective satellite cells may negatively impact resident myonuclear transcriptional activity contributing to impaired growth. Defining fusion-dependent and -independent roles of satellite cells and age-associated changes that negatively impact muscle adaptability will identify potential new targets to promote skeletal muscle growth in the face of inactivity, during aging and in the face of muscle wasting diseases.

项目总结