Functional similarities of microRNAs across different types of tissue stem cells in aging

Restoration of tissue homeostasis by controlling stem cell aging is a promising therapeutic approach for geriatric disorders. The molecular mechanisms underlying age-related dysfunctions of specific types of adult tissue stem cells (TSCs) have been studied, and various microRNAs were recently reported to be involved. However, the central roles of microRNAs in stem cell aging remain unclear. Interest in this area was sparked by murine heterochronic parabiosis experiments, which demonstrated that systemic factors can restore the functions of TSCs. Age-related changes in secretion profiles, termed the senescence(definition)-associated secretory phenotype, have attracted attention, and several pro- and anti-aging factors have been identified. On the other hand, many microRNAs are linked with the age-dependent dysregulations of various physiological processes, including "stem cell aging." This review summarizes microRNAs that appear to play common roles in stem cell aging.