Pleiotropic age-dependent effects of mitochondrial dysfunction on epidermal stem cells

Mitochondrial damage can accelerate features of aging, including impaired tissue regeneration, but little is known about how aging and this damage interact to impair tissue renewal. We show that mitochondrial oxidative stress in the epidermis alters wound healing depending on age. Epidermal mitochondrial damage accelerated wound closure in young mice; however, in older mice, this damage limited epidermal cell proliferation and reduced epidermal stem cell numbers, leading to delayed wound closure. Our findings uncover a surprising beneficial effect of mitochondrial dysfunction at young age (accelerated wound closure), and a potential mechanism for the reduced epidermal regeneration at older ages (stem cell depletion).