American scientists have found the causes of aging and were able to reverse it in mice. In particular, experts have discovered a molecular mechanism, the breakdown of which causes cells to age.
Mitochondria play a key role in the aging process. These are the "energy stations" of cells with their own DNA. When they are poorly performing their functions, senile diseases such as Alzheimer's and diabetes appear. Until now, it was believed that these diseases arise due to mutations in the mitochondrial DNA that cannot be reversed.
David Sinclair of Harvard Medical School and colleagues examined a group of genes called sirtuins. They bred mice without one of these genes, SIRT1. The mice showed signs of aging, but the levels of all proteins in the cells were normal, except for those encoded by mitochondrial DNA, RIA Novosti reports.
Scientists have found that, at the molecular level, a disruption in coordination between the genomes of the cell nucleus and its mitochondria plays a key role in the aging process. Dissociation begins with a drop in the level of the enzyme nicotinamide adenine dinucleotide (NAD), which decreases with age for unknown reasons.
Without it, the protein encoded by the SIRT1 gene cannot control the activity of one of the transcription factors (molecules involved in transcription, “reading” genetic information from DNA) - HIF. The HIF level rises and this disrupts the normal communication of the two genomes. Over time, this affects the ability of cells to produce energy, and the body ages.
Sinclair and his colleagues found a substance that turns into NAD in cells and restores the mechanism of communication of genomes in the cell. They gave it to mice two years old for a week and found that their muscle tissue became similar to that of six month old rodents. In addition, the researchers found a link between aging and cancer, as HIF, which is involved in the aging process, is also activated in cancer.