Not rejuvenation, but aging?
The main myth about human rejuvenation has been refuted
The increased activity of proteins that lengthen telomeres is associated with accelerated aging, and not its slowdown, as previously thought. This conclusion was reached by a group of American scientists from the University of California at Los Angeles, Boston University, Stanford University and the Institute for Aging Research at the non-profit organization Hebrew SeniorLife. The researchers' article was published in the journal Nature Communications (Lu et al., GWAS of epigenetic aging rates in blood reveals a critical role for TERT), briefly described in a press release on the EurekAlert! website.
Telomeres are the end sections of chromosomes that prevent the loss of DNA during cell division. However, each time during mitosis, telomeres shrink, which leads to a gradual increase in genome instability. Eventually, the cell stops dividing and dies. It is believed, however, that an enzyme called telomerase can prolong the life of cells by lengthening telomerase DNA.
Another marker of aging is methylation, the process of attaching methyl groups to DNA. In this case, certain genes may be suppressed or activated. For example, with age, genes that promote neurodegeneration are activated and DNA is suppressed, which prevents atherosclerosis. By the level of methylation, it is possible to determine the biological age of a person, which does not always coincide with the chronological one. People with a high proportion of methylated DNA have a high risk of premature death.
The researchers assessed the level of methylation in 9907 people and conducted a genome–wide association search, which examines the associations between a phenotypic trait – in this case, the proportion of methylated DNA - and various gene variants in all chromosomes. SNP – point mutations affecting one nucleotide – were identified, which were associated with a high level of methylation. It turned out that one of the loci for which the SNP data were characteristic was the TERT gene encoding a part of telomerase.
Point mutations in TERT associated with high levels of methylation are also associated with elongated telomeres. According to scientists, this means that anti-aging therapy based on increased telomerase activity, on the contrary, will contribute to aging. Thus, the opinion is refuted that rejuvenation of a person can be achieved by preventing shortening of the end sections of chromosomes.
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