Year: 2026
Type: preprint
Abstract: Summary Throughout life, somatic cells must preserve their identity while retaining the capacity to adapt. How this balance shifts with ageing and rejuvenation remains unclear. Here we identify miR-29 as a central point of convergence between the transcriptional programmes of physiological ageing and two routes to rejuvenation: induced reprogramming and the natural reset of early development. miR-29 rises with ageing, falls in both rejuvenation settings and shows the most conserved age-associated increase across vertebrates. miR-29 inhibition opposes transcriptional ageing, whereas mimics promote an older transcriptional state. Methylome analysis reveals a broader function: inhibition releases the miR-29 brake on remodelling, and mimic treatment reinforces it. This release increases methylation at repeat-associated CpGs and lowers epigenetic-clock estimates through unequal contributions in opposite directions. Inhibition also amplifies stimulus-induced methylation changes but reduces fidelity to lineage-specific methylation patterns. We extend this relationship to cancer, where low miR-29 expression marks tumours with younger epigenetic-age estimates yet greater methylation divergence from their tissue of origin. These findings identify miR-29 as a control point linking ageing, rejuvenation and cancer, and support a maladaptive trade-off model in which epigenetic fidelity is preserved at the expense of the plasticity needed for methylome maintenance and adaptation.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7223294546