It's time for lunch

Our mitochondria live by the clock

LifeSciencesToday based on the materials of the Weizmann Institute: Time to Eat. Weizmann Institute scientists find that our cells' power plants run on timers

When we eat is no less important than what we eat. A new study by scientists from the Weizmann Institute of Science and German specialists, recently published in the Proceedings of the National Academy of Sciences (Neufeld-Cohen et al., Circadian control of oscillations in mitochondrial rate-limiting enzymes and nutrient utilization by PERIOD proteins), shows that the work of mitochondria – organelles generating energy – is tightly regulated by the biological, or circadian, clock of the body. This may explain why people who eat and sleep in a phase that does not meet the requirements of their biological clock are at higher risk of developing obesity, diabetes and metabolic syndrome.

Dr. Gad Asher from the Weizmann Institute, who led the study, explains that the circadian clock, which almost any living creature has – from bacteria to flies and humans – controls the rhythms of sleep, activity, food intake and metabolism.

"In a way," he says, "it's like a daily planner informing the body of what to expect so that it can prepare for the future and act in the most optimal way."

Dr. Adi Neufeld-Cohen from the Asher Group, in collaboration with Dr. Maria S. Robles and Professor Matthias Mann from the Max-Planck-Institut für Biochemie Institute of Biochemistry, searched for circadian changes in mitochondria that, creating peaks and falls in the energy levels of cells, they would also participate in the regulation of their day and night cycle. The researchers identified and quantified hundreds of mitochondrial proteins, showing that the levels of the vast majority of them – 40% – reach their maximum once a day. In subsequent experiments, proteins that make up the circadian clock of mitochondria regulating this activity were identified. Surprisingly, the levels of most circadian proteins in mitochondria reached their peak four hours after the start of the light part of the daily cycle (in mice that are active at night).

Among the proteins discovered by the researchers was one of the key enzymes that determines the rate of sugar use for energy production. The amount of this protein reaches its maximum four hours after the start of daylight, which suggests that the ability of mitochondria to burn sugar reaches its peak at the same time. By providing the mitochondria with sugar, the researchers found that respiration and glucose utilization really reached their maximum around this time. In addition, they found that the level of the protein responsible for the intake of fatty acids into the mitochondria reaches a peak only by the eighteenth hour, and, as tests have shown, at the same time, the processing of fats is optimal.

In mice with a genetic mutation that disrupts the work of their common biological clock, the amount of these proteins did not change during the day, and the activity of splitting fats and sugar was constantly at the same level.

"These data confirm the results of previous studies in our laboratory, in which we showed that if mice eat only at night, when they are active, and not throughout the day, they eat the same amount of calories, but the lipid levels in their liver will be 50% lower," says Dr.r Asher. "In other words, the result depends not only on what you eat, but also on when you eat. If we knew more about the activity time of our cells, we could use different nutrients with greater health benefits."

Portal "Eternal youth" http://vechnayamolodost.ru  21.03.2016