BECN1 mutation increases autophagic flux in aged mice and improves aging phenotypes in an organ-dependent manner.

Macroautophagy/autophagy is necessary for lifespan extension in multiple model organisms and autophagy dysfunction impacts age-related phenotypes and diseases. Introduction of an F121A mutation into the essential autophagy protein BECN1 constitutively increases basal autophagy in young mice and reduces cardiac and renal age-related changes in longer lived mutant mice. However, both autophagic and lysosomal activities decline with age. Thus, whether autophagic flux is maintained during aging and whether it is enhanced in mice is unknown. Here, we demonstrate that old wild-type mice maintained functional autophagic flux in heart, kidney and skeletal muscle but not liver, and old mice had increased autophagic flux in those same organs compared to wild type. In parallel, mice were not protected against age-associated hepatic phenotypes but demonstrated reduced skeletal muscle fiber atrophy. These findings identify an organ-specific role for the ability of autophagy to impact organ aging phenotypes.