"Maiden memory" of genes

Muscle Genes Forget about Fitness

Kirill Stasevich, "Science and Life", based on the materials of Karolinska Institutet: Multifaceted genetic impact of training

If we regularly go to the gym, our muscle mass increases: to cope with the load, the activity of a variety of genes increases in the muscles, which help to strengthen protein synthesis, add new muscle fibers to the biceps, triceps, etc. If the exercises are stopped, the muscles shrink and weaken. However, maybe, despite such a decrease, the genes still remember that in the recent past we had to exercise a lot, and perhaps if we return to regular classes again, the genes, thanks to their memory, will turn on much faster, and we will reach the desired physical shape sooner than in the first once?

There really are molecular mechanisms in cells that allow DNA (i.e. genes) to "remember" life circumstances. Such mechanisms, called epigenetic, permanently change the activity of a particular DNA site, and even if those circumstances have long passed, epigenetic modifications keep certain DNA fragments in an appropriate state of readiness (or, conversely, in a state of complete unavailability, if a particular gene is not only not needed in such and such circumstances, and even hinders).

However, the muscles, alas, do not have such a "memory". Carl Johan Sundberg and his colleagues from the Karolinska Institute set up the following experiment: a little more than two dozen people who led a predominantly sedentary lifestyle had to swing their leg quickly for 45 minutes; this exercise should be done four times a week for three months. It was necessary to exercise only one leg, and the authors of the work took into account which leg each participant of the experiment trained, push (dominant) or not.

Then came nine months of rest, and then the same exercise had to be performed with both feet. At each stage of training, a biopsy was taken from the muscles to analyze the activity of muscle cell genes. As a result, it turned out that at the second stage of training, when a person worked with both legs, the activity of the genes was the same in the leg that was resting all the time, as in the one that had been diligently pumped a few months earlier. That is, the muscles did not remember past physical activity, and in the molecular-genetic sense, they started training from scratch. Some changes in the epigenetic modifications of genes seem to have been seen, but the researchers themselves doubt the reliability of the data obtained regarding the epigenetics of muscle genes. The full results are published on the PLOS Genetics website (Lindholm et al., The Impact of Endurance Training on Human Skeletal Muscle Memory, Global Isoform Expression and Novel Transcripts).

The fact that muscles forget about fitness, which they were tormented with recently, has its own meaning: maintaining a large muscle mass is quite expensive from the point of view of metabolism, and therefore, if the need for pumped muscles disappears, the body quickly cuts down on them, forcing the genes to forget how they worked under by the action of the load.

Here we can recall that two years ago we talked about another article published by the same researchers: then we were talking about epigenetic modifications that occurred with DNA in trained muscles, and which were related to muscle energy, regulation of inflammation, etc. About 5,000 such modifications were found, but they were searched for immediately after training, and then we said that the question immediately arises here: if you stop playing sports, how long will the altered picture of genetic activity last, how long will the methyl groups remain in their places on DNA? Well, now we know that it won't be long.

However, even if the muscles do not remember how they worked, the neurons that control them remember it. When we say that "hands remember", we mean just about neural memory: the sequence and coordination of movements are recorded in the chains of nerve cells, and therefore, after a long break, we can correctly pick up a tennis racket or get on a bicycle and not fall off. However, after a long break, you will have to spend quite a lot of effort to climb the mountain by bike.

Portal "Eternal youth" http://vechnayamolodost.ru  28.09.2016