Geriatric muscle stem cells switch reversible quiescence into senescence (Set 3; Adult vs. Young)

Regeneration of skeletal muscle depends on a population of adult stem cells (satellite cells) that remain quiescent throughout life. Satellite cell regenerative functions decline with aging. We report that geriatric satellite cells, compared to old and adult cells, are incapable of maintaining their normal quiescent state in muscle homeostatic conditions, and this irreversibly affects their intrinsic regenerative and self-renewal capacities. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions during physiological aging. Pure satellite cell populations from dissociated skeletal muscle from Young (2-3 months) and Adult (6 months) mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+)/CD34(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).