Telomerase

Telomerase is a specialised reverse transcriptase enzyme composed of a catalytic protein subunit (hTERT) and an RNA template component (hTR/TERC) that synthesises telomeric DNA repeats (TTAGGG in humans) at chromosome ends. In most adult somatic cells, telomerase expression is repressed, leading to progressive telomere shortening with each cell division until critically short telomeres trigger replicative senescence or apoptosis. Telomerase is constitutively active in stem cells, germ cells, and most cancer cells, enabling their extended proliferative capacity. Research into telomerase activation as an anti-ageing strategy has identified several compounds that upregulate hTERT expression. The synthetic peptide Epithalon (Ala-Glu-Asp-Gly), modelled on the naturally occurring pineal peptide epithalamin, has been studied for its ability to activate telomerase in human somatic cells, potentially extending their replicative lifespan. NAD+ and sirtuin pathways also intersect with telomere biology, as SIRT1 and SIRT6 are involved in telomere maintenance and DNA damage response at dysfunctional telomeres.