By Adam B. Dorfman

Epigenetic mechanisms is the study of how environmental information is translated into gene expression, which genes are read or not, has been especially crucial to learning how environmental signals influence the living cell.

Epigenetic Mechanisms

There are two important epigenetic mechanism’ that plays critical roles in genetic expression: DNA Methylation and the other is Histone Modification. Both alter the genes expression without changing the gene sequence, and these changes can be inherited. DNA methylation occurs when certain methyl molecules bind to the DNA to switch on or off a particular gene.

Histone modifications is the other epigenetic mechanism and it occurs when an environmental signals, binds to the histone, that covers the DNA, and causes in to detach; enabling sections of your genetic code to be read or not. Again these modifications enable certain regions of DNA to be exposed and over expressed or under expressed.

We know that eating certain diets or being exposed to pollutants and toxins, for instance, can change the expression of our genes. However, surprisingly, until recently, very little research had been pursued on the epigenetic mechanisms from endurance training.

Endurance Training

We have all been told we should perform moderate exercise five days a week to maintain and improve our physical conditions and immune systems to reduce the risk of various diseases including obesity and stroke. A new study in epigenetics has found that endurance training can actually change the way genes are read and consequently lead to improvements in metabolism and control over inflammation. The principal investigator of the study was Carl Johan Sundberg of the Karolinska Institutet in Sweden. The paper about the new study was published in Epigenetics.

In a press release, Sundberg said, “It is well-established that being inactive is perilous, and that regular physical activity improves health, quality of life and life expectancy. However, exactly how the positive effects of training are induced in the body has been unclear. This study indicates that epigenetics is an important part in skeletal muscle adaptation to endurance training.” One of the biggest obstacles to accurately study epigenetic changes is to distinguish epigenetic-specific changes from other factors such as behaviors and diet.

How to Isolate Behaviors and Diets?

To tackle the issue, researchers in Karolinska Institute recruited 23 young men and women for a series of clinical test including muscle biopsy; every one of them engaged in 45 minutes of endurance for four times a week during three months study. Each was required to cycle using only one leg, so everyone was actually a group study. This research helped scientists to analyze DNA methylation process in both legs as an effect of endurance training.

After three months of moderate training, the exercised leg of every volunteer became stronger than the other, confirming that endurance training did give physical improvement, but this was not the objective of the study. Using sophisticated genomic analysis, researchers found that changes within muscle cells’ DNA were a bit more interesting. The exercised legs featured new gene expressions in more than 5,000 sites on the genome of muscle cells. Some of them showed more changes, while others showed less.

These changes were significant, but the unexercised legs did not show the same thing. Many portions of the genome, which can amplify expression of proteins by genes known as enhancers, showed positive effects.

Lifestyle Changes Matter

Malene Lindholm, a graduate student at Karolinska Institute who also led the study said, “Many mysteries still remain, though.” There are at least two big questions yet to answer. First is whether or not the genetic changes triggered by endurance training linger if the person quits exercising. The second question is the possibility that different types or intensity of exercise affect gene expression. Despite those unanswered questions, the study did bring new understanding about epigenetics. Ms. Lindholm added, “Through endurance training — a lifestyle change that is easily available for most people and doesn’t cost much money, we can induce changes that affect how we use our genes and, through that, get healthier and more functional muscles that ultimately improve our quality of life.”

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