Hypothesis

We propose that telomere length in hypothalamic neural stem cells (hNSCs) operates as an informational‑entropy sensor that modulates the secretion of exosomal microRNAs, which in turn set the activation threshold of the IKK‑β/NF‑κB pathway in mediobasal hypothalamic neurons and microglia. When telomeres shorten beyond a critical entropy point, hNSC‑derived exosomal miRNA profiles shift toward NF‑κB‑promoting species, accelerating GnRH suppression and systemic aging.

Mechanistic basis

Telomere shortening alters chromatin accessibility at subtelomeric regions, influencing the nuclear export of specific RNA‑binding proteins that sort miRNAs into exosomes【https://pmc.ncbi.nlm.nih.gov/articles/PMC7411297/】. In hNSCs, this creates a biased miRNA cargo enriched for let‑7 family members that normally repress IKK‑β transcripts. Loss of telomere‑dependent sorting reduces let‑7 loading, increasing IKK‑β protein synthesis in target cells. Elevated IKK‑β triggers NF‑κB nuclear translocation, up‑regulating c‑Fos/c‑Jun and PKC activity, which transcriptionally silences GnRH【https://pmc.ncbi.nlm.nih.gov/articles/PMC3756938/】. This links a telomere‑based information metric to the immune‑neuroendocrine cascade that paces aging.

Testable predictions

• Prediction 1: hNSCs from old mice will show lower telomere length, reduced exosomal let‑7, and higher IKK‑β protein in adjacent microglia compared with young counterparts.
• Prediction 2: Forced telomere elongation in hNSCs (via TERT overexpression) will restore youthful exosomal let‑7 levels, decrease IKK‑β/NF‑κB signaling in the mediobasal hypothalamus, and elevate GnRH pulse frequency.
• Prediction 3: Pharmacological inhibition of exosome release (e.g., GW4869) will blunt the effect of telomere manipulation on NF‑κB activity, confirming the vesicle‑mediated route.

Experimental approach

1. Telomere modulation: Use AAV‑TERT or CRISPR‑based telomere shortening (TRF1‑DN) specifically in hNSCs of adult mice; verify telomere length by qFISH.
2. Exosome profiling: Isolate hypothalamic exosomes, perform small‑RNA sequencing to quantify let‑7 and NF‑κB‑modulating miRNAs.
3. Pathway read‑out: Measure IKK‑β phosphorylation, NF‑κB nuclear translocation, and c‑Fos/c‑Jun expression in FACS‑sorted neurons and microglia via immunoblotting and immunofluorescence.
4. Physiological output: Serial blood sampling for GnRH LH pulses, monitor estrous cyclicity, and assess lifespan and frailty indices.
5. Controls: Include exosome‑deficient hNSC lines (Rab27a knockout) to test vesicle dependence.

If telomere length directly governs the informational entropy of hNSC exosomal output, then rescuing telomere integrity should normalize the neuroimmune axis and delay aging phenotypes independent of global cell‑division counts. Conversely, uncoupling telomere state from exosome sorting would falsify the hypothesis, preserving the current view that hypothalamic aging is driven solely by extrinsic inflammatory cues.