Genetic "Messenger" May Affect Alcohol Disorders

By Jane Farrell

Changes in the levels of a genetic “messenger” are linked with the development of alcohol use disorders, according to researchers from the University of California, San Francisco.

The investigators found that when mice ingested excessive amounts of alcohol for a long time, levels of the protein BDNF dropped in the area of the brain that is important for decision-making.
The decline of BDNF in that area, the medial prefrontal cortex, corresponded with an increase in the level of a genetic messenger, or microRNA, called miR-30a-5p.

But when mice were treated with an inhibitor of miR-30a-5p, the level of BDNF was restored to normal. As a result, alcohol consumption was restored to moderate levels.

“Our results suggest BDNF protects against the transition from moderate to uncontrolled drinking and alcohol use disorders,” said Dorit Ron, senior author of the study and a professor in UCSF’s Department of Neurology. “When there is a breakdown in this protective pathway, however, uncontrolled excessive drinking develops, and microRNAs are a possible mechanism in this breakdown.”

Ron said that the newly discovered mechanism could be one explanation of why 10 percent of the population develop alcohol use disorders. “This study may be helpful for the development of future medications to treat this devastating disease,” she said.

The discovery was also noteworthy for the fact that it doesn’t inhibit the brain’s “reward pathways,” which contribute to a feeling of pleasure. One reason for the failure of many potential treatments for alcohol use disorders is that they inhibit those pathways.

The study was published in the journal Molecular Psychiatry.