Telomere Entropy Sensing Guides Adaptive OSK Dosing in vivo

Hypothesis

Transient OSK expression reduces epigenetic entropy, which is reflected in telomere length dynamics; telomere shortening or elongation serves as a real‑time readout of informational entropy, enabling closed‑loop titration of OSK dose to maintain entropy below a tissue‑specific threshold.

Mechanistic Basis

OSK‑induced TET2 activity demethylates CpG sites at subtelomeric regions, altering chromatin accessibility and influencing telomere repeat transcription (TERRA). TERRA levels modulate telomerase recruitment and heterochromatin formation, linking epigenetic state to telomere maintenance. When OSK drives demethylation, entropy of the methylome drops, permitting telomerase to act more efficiently and telomeres to lengthen; residual epigenetic noise sustains telomerase inhibition and progressive shortening. Thus telomere length becomes a downstream integrator of epigenetic entropy rather than a simple division counter.

Testable Predictions

1. In mice receiving inducible OSK, fluctuations in blood‑based telomere length (qPCR or STELA) will correlate inversely with changes in Horvath methylation clock acceleration (ΔAge) across weekly sampling.
2. Pharmacological inhibition of TET2 during OSK pulses will decouple telomere length changes from methylation clock reversal, producing stable or shortening telomeres despite epigenetic rejuvenation.
3. Tissue‑specific delivery (AAV‑OSK to liver vs. muscle) will yield distinct telomere entropy slopes, predictive of functional outcomes (e.g., ALT activity, fibrosis scores).
4. Adaptive dosing algorithms that adjust OSK inducer concentration to keep telomere length within a target band (±5% of baseline) will achieve greater methylation clock reversal and lower senescence marker expression than fixed‑dose regimens.

Experimental Design

• Animals: 20‑month‑old C57BL/6J mice, n=10 per group.
• Groups: (A) Fixed‑dose OSK (doxycycline 2 mg/kg 5 days on/2 days off), (B) Adaptive OSK (doxycycline adjusted weekly based on telomere qPCR from tail blood), (C) OSK + TET2 inhibitor (DMOG), (D) Vehicle control.
• Readouts: Telomere length (STELA) and methylation clock (Horvath) from blood every 7 days; tissue‑specific TERRA and 5‑hmC (dot blot) at endpoint; functional assays (grip strength, retinal OCT, liver ALT).
• Analysis: Mixed‑effects modeling of telomere vs. ΔAge trajectories; equivalence testing to determine if adaptive arm maintains telomere entropy within pre‑set bounds.

Falsifiability

If telomere length shows no statistically significant correlation with methylation clock changes across any OSK condition (p>0.05 after correction), or if adaptive dosing fails to produce superior epigenetic rejuvenation compared with fixed dosing despite maintaining telomere length within the target band, the hypothesis is falsified. Conversely, a consistent inverse correlation and improved outcomes in the adaptive arm would support the telomere‑entropy‑sensor model.