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Tuesday, July 23, 2013

Can we change our DNA methylation patterns?

It’s becoming increasingly evident that the pattern of DNA methylation in genes matters just as much as the actual DNA sequence. After all, methylation affects gene expression (whether genes are used to make protein products and how much product they make), which is really the point of having genes in the first place. Methylation patterns are not set for life, they can change over time. However, we're just beginning to understand what sorts of circumstances will alter methylation patterns. According to Tina Rönn and her colleagues from Lund University, exercise is one of them.

The scientists compared genome-wide DNA methylation in the adipose tissue (fat cells) of 23 ordinarily sedentary men before and after a six month exercise regimen. The exercise consisted of about 2 sessions/week of either an hour of spinning or an hour aerobics. The researchers found changes at nearly 20,000 nucleotides. When they checked to see which of these changes actually affected gene expression, they found differences in 197 different genes. Most of these genes showed an increase in DNA methylation, which corresponded to a decrease in gene expression. That is, most of the genes were making less protein products after exercise. Even more interesting, 53 of the affected genes are known to be implicated in obesity. 

I’ve written recently about differences in the methylation patterns of genes involved in metabolism in kids born after their mothers had gastric bypass surgeries. Those changes occurred in utero before the kids were born. This new data suggests that the methylation patterns can be purposefully altered by a person’s own activities. If this proves true, it may open up whole new ways of looking at and treating metabolic disorders.

Rönn T, Volkov P, Davegårdh C, Dayeh T, Hall E, Olsson AH, Nilsson E, Tornberg A, Dekker Nitert M, Eriksson KF, Jones HA, Groop L, & Ling C (2013). A Six Months Exercise Intervention Influences the Genome-wide DNA Methylation Pattern in Human Adipose Tissue. PLoS genetics, 9 (6) PMID: 23825961.