Klotho protects INS-1 pancreatic β-cells from senescence and enhances mitochondrial function

Aging is an important contributing factor for β-cell failure which could lead to the development of type 2 diabetes (T2D). Aging β-cell exhibits signs of senescence and develops senescence-associated secretory phenotype (SASP), causing the senescence and dysfunction of neighboring cells through paracrine action. <i>Klotho</i> is recognized as an anti-aging gene, and the corresponding protein is α-Klotho (KL). KL exerts potent anti-aging effects on multiple cell types, but its role in β-cell aging remains unclear. Here we showed that pancreatic INS-1 cell (a rat insulinoma cell line commonly used to study pancreatic β-cell function) developed the typical hallmarks of senescent cells when treated with doxorubicin <i>in vitro</i>, and this was accompanied by downregulation of endogenous KL expression. Supplementation with exogenous KL protein protected pancreatic INS-1 cell against senescence, as indicated by downregulation of senescent markers and SA-β-gal staining. Notably, these effects were associated with improved mitochondrial ATP production and mitochondrial dynamic balance, as well as reduced ROS production. Our study further revealed that INS-1 cell treated with doxorubicin exhibited a reduced insulin secretion response to glucose stimulation, while supplementation with KL could reverse this effect. Our results indicate the important role of KL in regulating β-cell senescence and provide new mechanistic insights into its role in β-cell aging.