A tiny protein made by mitochondria called MOTS‑c drops as we age and in diabetic mice. Giving extra MOTS‑c to old mouse pancreas cells or to diabetic mice reduced signs of cell aging and helped lower blood sugar. In people with type‑2 diabetes, blood levels of MOTS‑c are also lower, hinting it might play a role in the disease.

Mitochondria are crucial for cell survival and function, partly through peptides encoded by the mitochondrial genome. Although mitochondrial dysfunction is a hallmark of age-related diseases and senescence, the role of mitochondrial-genome-encoded peptides in pancreatic β-cell senescence during type 1 and type 2 diabetes pathogenesis is largely unexplored. Here we show that MOTS-c levels decrease with aging and senescence in pancreatic islet cells. Treating aged C57BL/6 mouse pancreatic islets with MOTS-c reduced pancreatic islet senescence by modulating nuclear gene expression and metabolites involved in β-cell senescence. MOTS-c treatment improved pancreatic islet senescence and glucose intolerance in S961-treated C57BL/6 and in nonobese diabetic mice. In humans, circulating MOTS-c levels are lower in type 2 diabetes patients compared with healthy controls. Our findings suggest that mitochondrial-encoded MOTS-c regulate pancreatic islet cell senescence and that MOTS-c could act as a senotherapeutic agent to prevent pancreatic islet cell senescence and diabetes progression.