Epigenetic Priming of Autophagic Genes Explains Persistent Longevity Benefits After mTOR Inhibition\n\nHypothesis: Transient mTOR inhibition induces a lasting epigenetic state at autophagy‑ and lysosomal‑gene promoters that sustains autophagic flux and stress resistance after the drug is cleared, accounting for the prolonged healthspan benefits observed with rapamycin or intermittent fasting.\n\nMechanistic rationale:\n- mTORC1 suppression lowers cytosolic acetyl‑CoA consumption and increases nuclear acetyl‑CoA, promoting histone acetylation (e.g., H3K27ac) at promoters of ATG genes and lysosomal biogenesis regulators (TFEB, LAMP1). This creates an open chromatin configuration that enhances transcription even when mTOR activity rebounds.\n- The resulting transcriptional "memory" maintains elevated LC3‑II turnover and prevents p62 accumulation, thereby preserving proteostasis and cellular resilience without ongoing drug exposure.\n- Because this chromatin state is self‑reinforcing through recruitment of bromodomain‑containing readers that further attract acetyltransferases, it can persist for weeks after mTOR inhibition ends, matching the observed longevity extension after late‑life rapamycin treatment.\n\nTestable predictions:\n1. Chromatin signature: Mice treated with rapamycin for 2 weeks will show increased H3K27ac at ATG5, ATG7, LAMP2, and TFEB promoters in liver and skeletal muscle; the enrichment will remain significant ≥4 weeks after drug withdrawal.\n2. Dependency on acetylation: Co‑administration of a histone acetyltransferase inhibitor (e.g., CBP/p300 inhibitor A‑485) during rapamycin exposure will abolish the persistent increase in autophagic flux (measured by LC3‑II/I ratio and p62 degradation) and eliminate the lifespan extension seen with rapamycin alone.\n3. Sufficiency: Mice expressing a constitutively acetylated histone H3 mimic (H3K27Q) specifically in hepatocytes will exhibit elevated basal autophagy and extended healthspan without rapamycin treatment, phenocopying the drug’s persistent effects.\n4. Human relevance: Peripheral blood mononuclear cells from older adults undergoing a 4‑week intermittent rapamycin regimen will display heightened H3K27ac at autophagy gene loci that persists for at least 2 weeks post‑intervention, correlating with improved markers of metabolic stress resistance.\n\nFalsifiability: If any of the following occurs, the hypothesis is weakened: (a) Rapamycin fails to increase promoter‑specific histone acetylation; (b) The acetylation increase does not outlast drug presence; (c) Blocking acetylation does not diminish the lingering autophagic flux or longevity benefit; (d) Artificial histone acetylation does not reproduce the persistent autophagy phenotype. Each outcome can be assessed with standard ChIP‑qPCR, autophagic flux assays, and survival studies, making the hypothesis empirically tractable.