ASAP3, an actin cytoskeleton remodeling protein, is upregulated in aged mouse livers and H₂O₂-stressed hepatocytes. Its genetic knockout extended lifespan, improved cognitive and motor performance, and remodeled systemic metabolism in both sexes. Mechanistically, ASAP3 deficiency reduced abnormal F-actin accumulation (lowering F-actin/G-actin ratio), restored autophagic flux, decreased mitochondrial reactive oxygen species, and preserved mitochondrial membrane potential. Critically, blocking autophagy abolished the anti-senescence benefit of ASAP3 knockdown, and disrupting F-actin assembly with cytochalasin D rescued suppressed autophagic flux — establishing a causal actin→autophagy→senescence pathway. Serum lipidomics in knockout mice further enriched pathways involving actin regulation, autophagy, and primary bile acid biosynthesis.
This finding adds meaningful granularity to a growing body of work linking cytoskeletal dynamics to cellular aging. The actin-autophagy connection is underappreciated: rigid F-actin networks are known to mechanically obstruct autophagosome trafficking, and this study provides genetic proof-of-concept in a metabolically central organ. The liver's role as a systemic aging amplifier makes hepatic targets particularly attractive for longevity interventions. However, several limitations temper enthusiasm: all data are murine, and ASAP3's human orthologue and its expression trajectory in human aging remain uncharacterized. Lifespan extension magnitude and cognitive effect sizes are unreported in the abstract, making it difficult to gauge clinical relevance. Still, identifying a druggable cytoskeletal regulator that bridges mitochondrial health, autophagy, and whole-organism aging is a genuinely novel mechanistic contribution — incremental in scope but potentially paradigm-shifting for hepatic aging therapeutics.