GWSMHS professor to study correlation between genetics and susceptibility to drug abuse

Norman H. Lee, Ph.D., professor of pharmacology at the George Washington University School of Medicine and Health Sciences (SMHS), received a total of $405,001 in grant funding from the National Institute on Drug Abuse (NIDA) to continue to study the correlation between genetics and susceptibility to drug abuse. The award will fund Lee's continuing research on drug addiction, titled "Conditional Dicer1 Manipulation to Study miRNA Involvement in Oploids Addiction," for the next two years.

Lee will act as co-principal investigator of the grant, using his expertise in genomics to collaborate with Gregory Elmer, Ph.D., behavioral geneticist at the University of Maryland School of Medicine. Their research will focus primarily on morphine addiction in mouse models. In previous research, the researchers placed mice in a self-administration chamber and taught them to press a lever a certain number of times to receive an injection of morphine, which stimulates the reward center of the brain. While one group of mice eventually stopped pressing the lever, another group continued to work harder and pressed the lever many more times in order to receive an injection of morphine. They found that in this group of mice, there was a significant change in the expression of genes involved in the architecture of neurons in the brain, leading this group to abuse the drug.

"We are asking the question, 'What is it about the brain in certain individuals that's changing and leading them to become more susceptible to abusing drugs, despite the adverse consequences?'" said Lee.

The researchers discovered that the changes occurring in the brain are due in large part to an enzyme being turned on, called Dicer. This enzyme then turns on the expression of small RNA molecules, called micro-RNA (miRNA), which are important for gene regulation. The miRNAs in turn dampen or turn off genes, which Lee believes leads the mice to continue to self-administer and abuse morphine. With this grant, they will be able to determine which genes the miRNAs are dampening or turning off and which are important for drug addiction.

By combining their expertise to study drug addiction, Lee and Elmer hope to find a way to therapeutically target the genes being turned off in an effort to treat drug addiction.

Source: George Washington University