Naturally occurring p16(Ink4a)-positive cells shorten healthy lifespan

Cellular senescence, a stress-induced irreversible growth arrest often characterized by p16(Ink4a) expression and a distinctive secretory phenotype, prevents the proliferation of preneoplastic cells and has beneficial roles in tissue remodelling during embryogenesis and wound healing. Senescent cells accumulate in various tissues and organs over time and have been speculated to play a role in aging. To explore the physiological relevance and consequences of naturally occurring senescent cells, we used a previously established transgene, INK-ATTAC, to induce apoptosis in p16(Ink4a)-expressing cells of wild-type mice by injection of AP20187 twice a week starting at one year of age. Here we show that compared to vehicle alone, AP20187 treatment extended median lifespan in both male and female mice of two distinct genetic backgrounds. Clearance of p16(Ink4a)-positive cells delayed tumorigenesis and attenuated age-related deterioration of several organs without apparent side effects, including kidney, heart and fat, where clearance preserved the functionality of glomeruli, cardio-protective K(ATP) channels, and adipocytes, respectively. Thus, p16(Ink4a)-positive cells that accumulate during adulthood negatively influence lifespan and promote age-dependent changes in multiple organs, and their therapeutic removal may be an attractive approach to extend healthy lifespan.