Hypothesis

Combining senolytic clearance with pharmacologic mitophagy activation reduces SASP‑driven paracrine senescence and blocks PANoptosis in aged c‑Kit+ CPCs, thereby restoring regenerative capacity.

Rationale

• Aged hearts accumulate senescent c‑Kit+ CPCs that secrete SASP factors (MMP‑3, PAI‑1, IL‑6, IL‑8) which induce paracrine senescence in neighboring cells [1]
• SASP promotes NLRP3 inflammasome activation, triggering PANoptosis—an inflammatory cell death pathway amplified in the aged myocardium [6]
• Mitochondrial dysfunction in aged CPCs impairs biogenesis and oxidative phosphorylation, raising ROS that fuels both senescence and inflammasome signaling [2]
• Enhancing mitophagy (e.g., with Urolithin A) removes damaged mitochondria, lowers ROS, suppresses NLRP3 activation, and improves autophagic flux, which directly counters senescence induction [3]
• Senolytics (dasatinib + quercetin) eliminate existing senescent CPCs and abate their SASP [5], but do not address the underlying metabolic stress that can re‑induce senescence in surviving progenitors

Testable Prediction

Aged mice receiving combined therapy (D+Q + Urolithin A) will show:

1. Greater reduction in p16^INK4A^‑positive and SA‑β‑gal‑positive CPCs compared with D+Q alone
2. Lower SASP cytokine levels (IL‑6, IL‑8) in cardiac interstitial fluid
3. Decreased markers of PANoptosis (cleaved caspase‑8, caspase‑1, MLKL phosphorylation) in the myocardium
4. Improved mitochondrial respiration and ATP production in isolated CPCs
5. Enhanced ejection fraction and reduced fibrosis after myocardial infarction relative to senolytic monotherapy

Experimental Design

• Groups (n=10 per group, aged 20‑month‑old mice):
  • Vehicle control
  • D+Q only
  • Urolithin A only
  • D+Q + Urolithin A
• Treatments administered for 4 weeks; D+Q given intermittently (5 days on/2 days off) per prior protocols [5], Urolithin A daily via diet.
• Endpoints: flow cytometry for CPC senescence markers, ELISA for SASP cytokines, immunoblot for PANoptosis effectors, Seahorse analysis for mitochondrial function, echocardiography and histology for cardiac function.
• Statistical analysis: ANOVA with post‑hoc Tukey; significance set at p<0.05

Falsifiability

If the combination does not produce a statistically significant improvement over D+Q alone in any of the primary endpoints (senescence burden, SASP, PANoptosis markers, mitochondrial output, or functional recovery), the hypothesis is refuted. Conversely, a clear additive or synergistic benefit supports the mechanistic link between mitophagy, inflammasome suppression, and sustained CPC regenerative capacity.