A study in the September issue of Cell Metabolism, a Cell Press publication, may give new meaning to the adage, "You are what you eat."
The DNA isolated from the muscles of people with diabetes bears chemical marks not found in those who respond normally to rising blood sugar levels, according to the report. The epigenetic marks in question are specifically found on a gene that controls the amount of fuel, in the form of glucose or lipids, that cells burn. Those marks also show up in the skeletal muscle of people with prediabetes, suggesting that the DNA modification might be an early event in the development of the disease.
Those changes rapidly reprogram the gene's activity without altering the underlying DNA sequence at all. They suggest a way that environmental factors—what we eat or how active we are—may perhaps influence our genes, for better or for worse.
Indeed, the researchers show that the hypermethylation of the gene known as PGC-1? for short (peroxisome proliferator-activated receptor ? [PPAR?] coactivator-1?) also takes place in isolated muscle fiber cells when they are exposed to an inflammatory factor or to free fatty acids.
"These changes take place when you expose muscle to systemic factors that mimic the diabetic condition," said Juleen Zierath of the Karolinska Institutet in Sweden. Such changes to the epigenetic imprint have been seen before, explain Zierath and Romain Barrès, the study's first author. For instance, chemical modification of genes are responsible for developmental changes that take place as cells differentiate. They are the reason that keratin is produced in the skin but not in blood, for instance. In contrast, the changes they've now revealed take place in cells of the body that are fully mature.
