Effects of the systemic environment on muscle aging

全身环境对肌肉衰老的影响

• 批准号: 7908967
• 负责人: Irina M Conboy
• 金额: $ 18.54万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7908967
• 关键词: Activins; Adult; Age; Aging; Animals; Attenuated; Blood Circulation; Calibration; Cell Culture Techniques; Cell Proliferation; Cells; Data; Disease; Dominant Negative Receptor; Environment; Family; Follistatin; Generations; Goals; In Vitro; Injury; Intramuscular; Life; Ligands; Methods; Molecular; Mus; Muscle; Muscle Cells; Muscle satellite cell; Natural regeneration; Notch Signaling Pathway; Organ; Parabiosis; Pathway interactions; Pattern; Process; Proliferating; Protein Family; Proteins; Regulation; Relative (related person); Research; Research Personnel; Role; Serum; Signal Transduction; Skeletal Muscle; Smad Proteins; Smad protein; Stem cells; System; Testing; Tetracyclines; Therapeutic; Tissues; Transforming Growth Factor beta; Work; Wound Healing; activin A; age related; aged; attenuation; cell injury; design; in vivo; inhibitor/antagonist; injured; juvenile animal; muscle aging; myogenesis; notch protein; regenerative; repaired; response; satellite cell; stem; tissue regeneration; trait; young adult

DESCRIPTION (provided by applicant): Adult skeletal muscle robustly regenerates throughout adult life but fails to do so in old age. The reason for such a decline in the regenerative potential is not well understood and the relative roles of the changes in muscle cells versus the alterations in their aged environment have not been defined. Recently is has been shown that a young systemic milieu restores the activity of the regeneration-specific Notch pathway and enhances repair of old muscle, suggesting that largely intact regenerative potential of aged satellite cells is not properly triggered in the aged environment. Our most recent data suggest that it is not simply the lack of "positive" systemic factors that causes impaired organ stem cell activation and tissue repair in the old, but that the aged systemic and muscle niches actually inhibit Notch activation and the regenerative potential of both old and young satellite cells. Namely, satellite cells isolated from old muscle or exposed to aged mouse serum in vitro are inhibited in their regenerative capacity and lack Notch activation. Moreover, our preliminary data identifies a molecular mechanism of this age-related inhibition by demonstrating that the reduced regenerative potential of satellite cells in the aged environments stems from excessive TGF-beta/pSmad signaling induced in these cells by their aged niches, which in turn is a result of the elevated levels of TGF- beta-family ligands in aged circulation and muscle tissue. Very importantly, our preliminary results suggest that both myogenic potential and Notch activation can be rejuvenated by attenuation of TGF-beta/pSmad signaling in satellite cells. These studies emphasize high therapeutic relevance of understanding the regulation of adult myogenesis by TGF-beta super-family and of designing the approaches for tunable calibration of TGF-beta/pSmad signaling in muscle stem cells. In order to decipher the age-related role of TGF-beta/pSmad signaling in muscle repair and to progress toward therapeutic applications, it is needed to determine 1) what are the "youthful" positive versus "aged" negative levels of TGF-beta-superfamily ligands in circulation and muscle tissue; 2) at what age-related levels TGF-beta/pSmad signaling becomes excessive and "negative" for satellite cell regenerative capacity and 3) how to design a tunable system for a precise "youthful" recalibration of TGF-beta/pSmad signaling in satellite cells. These goals will be approached here in the proposed Specific Aims.

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