Sirtuin-1 not only slows down aging, but also regulates the daily rhythm
The SIRT1 protein, part of the sirtuin family, is involved in many intracellular processes, including those underlying aging. The researchers hope that activating this protein with pharmacological drugs such as resveratrol can increase life expectancy and improve people's health. Similar results have so far been observed when conducting studies on various animal models.
Recently, scientists at the Massachusetts Institute of Technology, working under the leadership of Leonard Guarente, have received evidence that SIRT1 is involved not only in ensuring longevity and a long period of health, but also in regulating the circadian rhythms of the body.
The researchers came to these conclusions as a result of monitoring the natural activity of mice. The normal circadian cycle of mice falls a little short of 24-hour days and is approximately 23.5 hours. In the absence of SIRT1 in the brain of animals, their circadian rhythm lengthens and approaches 24 hours. At the same time, a twofold increase in the synthesis of SIRT1 in the brain of mice shortens their daily cycle, and a fivefold increase in the synthesis of this protein makes it even shorter.
According to Guarente, the concentration of SIRT1 in the brain can affect the functioning of the body's biological clock, the function of which is performed by a group of cells known as the suprachiasmatic nucleus, which ensures the adaptation of the body to seasonal changes in the length of daylight. Previously, researchers noticed that as mice age, their biological clock slows down, and the daily cycle approaches 24 hours. They wanted to find out whether this increase in the day is correlated with an age-related decrease in the level of SIRT1 in the biological clock of the brain.
To do this, they disrupted the daily rhythm of the animals by abruptly shifting the time of day and night in the laboratory by four hours. Young mice, as a rule, adapted their rhythms to new conditions within about two days, whereas old animals needed up to 8 days to do this. Another series of experiments showed that young mice whose brains lacked SIRT1 got used to changing the light mode within 4 days, and old animals with elevated levels of SIRT1 coped with this task somewhat faster. All this indicates that SIRT1 is at least partially responsible for the ability of animals to adapt to changing light conditions. Moreover, the researchers found that the concentration of SIRT1 in the cells of the suprachiasmatic nucleus is interrelated with the levels of proteins that perform important functions in the work of the biological clock.
In separate experiments, scientists have shown that mice whose biological clocks are set to a day, the duration of which is closest to 24 hours, live longer than animals with a faster or slower "ticking" biological clock. Guarente believes that the constant reconfiguration of the circadian biological clock can have a stressful effect, accelerating the aging process.
The results of the work were reported at the conference "Metabolism, Diet and Diseases", held on May 29-31 in Washington.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Science News:
Antiaging protein helps set daily rhythms.
07.06.2012