KGI scientists identify new gene regulator that keeps hearts healthy even under intense exercise

Providing a medical explanation for why exercise is good for the heart, a team of scientists from Brazil pursuing a study that started in Dr. Ian Phillips' lab at Keck Graduate Institute (KGI) has discovered a new gene regulator called MicroRNA 29 that keeps hearts healthy even under intense exercise.

"Now, we're beginning to get to the molecular basis of why exercise is good for you," said Phillips, KGI's Norris Professor of Applied Life Sciences. "It's well known that athletes get large hearts and they remain healthy while people with large hearts, who are not athletes, are in big trouble. But we've never known before why they were different."

Dr. Edilamar de Oliveira, a biochemistry professor in the Physical Education School at the University of Sao Paulo, worked with Phillips while doing postdoctoral studies at KGI from 2007-09. Applying what she learned about MicroRNAs to her research on physical training and cardiac hypertrophy after returning to Brazil, de Oliveira found MicroRNAs act as brakes on specific genes, inhibiting what proteins those genes produce.

De Oliveira and her team found that rats, who trained like athletes (two and three times a day) on a 10-week regimen involving swimming with 5% weights overload, expressed much higher levels of MicroRNA 29 than sedentary rats. And, even though the athletic rats' hearts were enlarged, they did not develop an excess of collagen fibers, which interferes with the heart's ability to pump effectively. (Bad hearts are full of collagen and good hearts have very little collagen.)

Results of the study were published in the latest issue of the journal Physiological Genomics. The first author is Ursula Soci, one of De Oliveira's PhD students.

"The paper reports the discovery of the regulator of the genes that decide whether the heart is going to be healthy or unhealthy," Phillips said.

The discovery has broad implications for individuals with heart disease and congestive heart failure.

Because MicroRNA 29 stops collagen genes from building up in the heart, injections of it might have therapeutic value, according to Phillips.

De Oliveira has received a grant for the next step in their research, which will involve injecting hypertensive rats with MicroRNA 29 to see if the gene inhibiter can prevent the development of large, unhealthy hearts because of hypertension.

SOURCE Keck Graduate Institute