Reviewed by John M. Grohol, Psy.D. on July 31, 2008
The brain tissue was collected during autopsies and may eventually help explain an underlying cause of major depression and suicide.
This is apparently the first study to show that proteins that modify DNA directly are more highly expressed in the brains of people who commit suicide. These proteins are involved in chemically modifying DNA in a process called epigenomic regulation.
Michael O. Poulter, the lead researcher explains, “We have about 40,000 genes in every cell and the main reason a brain cell is a brain cell is because only a small fraction of the genes are turned on. The remaining genes that are not expressed are shut down by an epigenetic process called DNA methylation.”
The rate of methylation in the suicide brains was found to be much greater than that of the control group. Importantly, one of the genes they studied was shown to be heavily chemically modified and its expression was reduced. This particular gene plays a major role in regulating brain activity. “Interestingly, the nature of this chemical modification is long term and hard to reverse, and this fits with depression,” says Poulter.
“The whole idea that the genome is so malleable in the brain is surprising. Finding that epigenetic mechanisms continue to influence gene expression is pretty unusual,” says Poulter.
“These observations open an entirely new avenue of research and potential therapeutic interventions.”
The research was published in the journal Biological Psychiatry.
Source: The University of Western Ontario