ST. LOUIS -- In research funded by the National Institutes of Health and the American Heart Association and published in EMBO Molecular Medicine, Saint Louis University investigator ngel Baldn, Ph.D., found that the microRNA miR-33 plays a key role in regulating bile metabolism. Further, the research suggests that, in an animal model, the manipulation of this microRNA can improve the liver toxicity that can be caused by statins.
"As we learn more about the way cholesterol is moved and metabolized through the body, we have more tools at our disposal to try to limit potential side effects of cholesterol-managing drugs like statins," said Baldn, who is assistant professor of biochemistry and molecular biology at Saint Louis University.
This study continues Baldn's exploration of the microRNA miR-33, which is expressed from within SREBP-2, an important gene in the body that previously had been shown to regulate cholesterol metabolism. In earlier research, the Baldn laboratory found that miR-33 plays a key role in regulating cholesterol. In particular, his team found that decreasing the levels of the microRNA (which is a piece of genetic coding) helped to raise HDL, or "good cholesterol," in an animal model. Five laboratories, including Baldan's, simultaneously reported these results in 2010.
Now, as Baldn continues to study the role of miR-33, he has examined two particular bile transporters, ABCB11 and ATP8B1, and found that miR-33 directly regulates these transporters. The research team found that when they silenced miR-33, turning off the microRNA's signal, they caused increases in bile secretion from the liver, so more bile was recovered in the gallbladder.
Further confirming the suspicion that this pathway was responsible for regulating the flow of bile, researchers treated two groups of mice with an anti-miR-33 drug and tracked radioactively labeled cholesterol as it moved through and was eliminated by these animal
|Contact: Carrie Bebermeyer|
Saint Louis University