Hypothesis

Timing dasatinib plus quercetin (D+Q) administration to peaks in a circulating senescence-associated secretory phenotype (SASP) vesicle‑miRNA signature yields superior senescent‑cell clearance with lower off‑target chromatin stress than fixed‑interval regimens.

It's reasonable to assume that aligning drug exposure with SASP peaks maximizes senescent‑cell apoptosis while sparing non‑senescent proliferating compartments. The D+Q combination clears senescent cells by targeting SRC/ABL kinases with dasatinib and PI3K/AKT‑BCL2 pathways with quercetin, but intermittent dosing can provoke transient senescence‑like chromatin alterations in non‑senescent progenitors, as seen in influenza‑infected lungs where D+Q worsened pathology despite immune benefits【https://pmc.ncbi.nlm.nih.gov/articles/PMC12181558/】【https://pmc.ncbi.nlm.nih.gov/articles/PMC12748518/】. These off‑target effects likely stem from SRC/ABL inhibition causing DNA‑damage signaling in proliferating cells that are not truly senescent. Because senescent cells secrete a characteristic SASP packaged into extracellular vesicles, the abundance of specific miRNAs (e.g., miR-34a, miR-146a, miR-21) in plasma correlates with the active senescent burden and rises before tissue damage accrues【https://pubmed.ncbi.nlm.nih.gov/41564845/】. Administering D+Q only when this vesicle‑miRNA signature exceeds a pre‑defined threshold would concentrate drug exposure during windows of maximal senescent‑cell presence, thereby increasing the probability of hitting the intended apoptotic targets while limiting the duration of SRC/ABL inhibition in proliferating compartments.

Experimental design

To test this, we propose using a p16-3MR mouse model in which hepatic senescence is induced by chronic CCl4 exposure. Plasma exosomal miR-34a/miR-146a/miR-21 levels will be measured twice weekly. One cohort receives adaptive D+Q (100 mg/kg dasatinib + 1000 mg/kg quercetin oral) for three consecutive days whenever the combined miRNA score surpasses the 75th percentile of baseline; a control cohort receives the same total drug amount delivered as a fixed biweekly 2‑day regimen regardless of biomarker levels. Primary endpoints after eight weeks are:

• Senescent‑cell frequency measured by p16^INK4a^+ cells in liver immunofluorescence
• Fibrosis quantified by hydroxyproline content
• Off‑target DNA‑damage assessed by γH2AX co‑localization with Ki67^+ hepatocytes
• Functional readouts serum ALT and survival

We predict the adaptive group will achieve equal or greater reduction in p16^INK4a^+ cells, show significantly lower γH2AX^+/Ki67^+ fractions, exhibit less collagen deposition, and retain better liver function than the fixed‑interval group.

Falsifiability

Falsification occurs if adaptive dosing fails to reduce off‑target γH2AX in proliferating cells or does not improve fibrosis or survival relative to the fixed schedule, indicating that timed secretion‑based dosing does not confer a therapeutic advantage over conventional intervals. A negative result would redirect efforts toward refining SASP biomarkers or exploring alternative senolytic schedules.