Hypothesis

Time‑restricted eating (TRE) induces a metabolic siege that shifts senescent cells into an autophagy‑dependent survival state, rendering them vulnerable to pharmacological autophagy inhibition. The synergistic siege‑then‑blockade approach will selectively eliminate senescent cells while sparing proliferating tissues.

Mechanistic Rationale

It's known that prolonged fasting mTORC1 activity drops and AMPK rises triggering ULK1‑dependent autophagosome formation 1. In senescent cells lysosomal capacity is already heightened to manage the secretory phenotype creating a dependency on autophagic flux for intracellular homeostasis 3. We're proposing that TRE‑induced AMPK activation not only increases autophagosome formation but also primes lysosomes by upregulating V‑ATPase subunits and cathepsin activity thereby increasing the reliance of senescent cells on autophagy for SASP component turnover. When autophagy is subsequently blocked with chloroquine or hydroxychloroquine lysosomal deacidification leads to accumulation of undegraded cargo oxidative stress and apoptosis specifically in the primed senescent pool.

Testable Predictions

1. In human peripheral blood mononuclear cells a 16‑hour daily TRE regimen for 5 days will increase LC3‑II/I ratio and p62 degradation markers indicating heightened autophagic flux 2.
2. Senescent cells isolated after TRE will show elevated expression of lysosomal genes LAMP1 LAMP2 CTSD compared with ad libitum controls.
3. Adding chloroquine during the refeeding window will cause a disproportionate increase in Annexin V‑positive senescent cells versus non‑senescent counterparts.
4. The combined TRE + chloroquine regimen will reduce circulating SASP factors IL‑6 IL‑8 more than either intervention alone.
5. Genetic knockdown of ATG5 in senescent cells will abrogate the sensitizing effect of TRE confirming autophagy dependence.

Experimental Design

• In vivo: Mice engineered with p16‑3MR reporter will undergo either ad libitum feeding 16:8 TRE for 2 weeks or TRE plus chloroquine (50 mg/kg i.p. every other day during the feeding window). Senescent cell burden will be quantified by bioluminescence and flow cytometry for p16‑positive cells. SASP cytokines will be measured in plasma.
• Ex vivo: Human PBMCs from volunteers undergoing a supervised 5‑day 16:8 TRE protocol will be cultured with or without chloroquine during the final 4 hours. Senescence will be assessed by SA‑β‑gal staining and p21 expression; autophagic flux by mCherry‑GFP‑LC3 reporter.
• Controls: Include groups receiving chloroquine alone and TRE with a lysosomotropic inert compound (e.g., sucrose) to rule out off‑target toxicity.

Potential Pitfalls and Alternatives

If TRE fails to increase autophagic flux in senescent cells the hypothesis would be falsified suggesting that the senescence‑associated lysosomal remodeling does not translate into heightened autophagy dependence. Conversely if chloroquine toxicity occurs irrespective of TRE it's likely that the selective window is narrower than anticipated prompting exploration of more specific autophagy inhibitors (e.g., ULK1 inhibitors) or genetic approaches.