As tissues age, the epigenetic regulation of the genome undergoes a large-scale restructuring. According to a scientific review by Dr. Chinta Sidharthan on the medical portal News-Medical, these age-related shifts affect DNA methylation, chemical modifications of histone proteins, overall chromatin structure and the activity of non-coding RNAs, infohub.kz reports.
As a result of such changes, the precision of genetic programs is disrupted, and cells lose their original specialization and their capacity for repair, which contributes to the development of chronic diseases and a general functional decline of the body.
Researchers pay particular attention to the phenomenon of "epigenetic drift." Over a lifetime, under the influence of external factors, stress, inflammation and diet, methyl marks are redistributed across DNA, distorting the work of signaling pathways such as Wnt and MAPK. To track such disruptions, researchers have developed so-called epigenetic clocks, which assess the true biological age of tissues. The accumulation of epigenetic errors has already been linked to age-related memory decline in animals and to the activation of cancer genes such as CDKN2A.
At the same time, epigenetic marks are reversible. Experiments in mice confirm that physical activity, calorie restriction and partial cellular reprogramming using Yamanaka factors (Oct4, Sox2 and Klf4) can return the molecular profiles of old cells to a younger state. Scientists have already managed to restore vision in elderly rodents, but introducing epigenomic editing into human medicine requires lengthy safety testing.