The aging liver not only declines in function but also accelerates systemic aging and shortens lifespan. Identifying key molecular targets to delay liver aging is important for promoting health and longevity. ASAP3 is involved in cytoskeletal remodeling, but its role in aging remains unexplored. Here, we found that ASAP3 expression was upregulated in aged mouse livers and H2O2-induced AML12 cells. In AML12 hepatocytes, ASAP3 knockdown attenuated H2O2-induced senescence, enhanced autophagic flux, reduced mitochondrial ROS, and restored mitochondrial membrane potential, whereas ASAP3 overexpression had opposite effects. Phalloidin staining and western blot analysis showed that ASAP3 knockdown significantly reduced the abnormal accumulation of F-actin and F-actin/G-actin ratio, while ASAP3 overexpression aggravated F-actin accumulation, and increased F-actin/G-actin ratio in AML12 cells. In addition, inhibition of autophagy abolished the alleviating effect of ASAP3 knockdown on senescence, whereas enhancing autophagy protected against cellular senescence induced by ASAP3 overexpression. Furthermore, disruption of F-actin assembly with cytochalasin D rescued the suppression of autophagic flux caused by ASAP3 overexpression. In vivo, ASAP3 knockout extended lifespan, improved cognitive and motor functions, and remodeled systemic metabolism in both sexes. ASAP3 knockout mice also showed reduced senescence phenotype, maintained F-actin structure, and enhanced autophagic flux in the liver. Furthermore, serum lipidomics revealed significant enrichment of pathways related to actin cytoskeleton regulation, autophagy, and primary bile acid biosynthesis in Asap3-/- mice. Collectively, these findings demonstrate that ASAP3 is a negative regulator of liver aging, promoting senescence and impairing autophagy and mitochondrial function by disrupting actin cytoskeleton dynamics. Targeting ASAP3 may represent a promising strategy to delay hepatic aging and extend healthspan.
