Researchers studying myxomatous mitral valve degeneration (MMVD) — a leading age-related heart condition in dogs and humans — discovered that senescent valve cells have severely impaired autophagy. When autophagy was restored using rapamycin, torin-1, or ATG gene overexpression, key senescence proteins p16 and p21 were degraded and the damaging senescence-associated secretory phenotype (SASP) was reduced. Crucially, the study identified SQSTM1/p62 as the autophagy receptor that selectively targets p16 and p21 for autophagic destruction — a mechanism completely independent of the ubiquitin-proteasome system. This represents a first-of-its-kind finding with broad implications for age-related degenerative diseases.
