Posted on Sep 18, 2012, 6 a.m.
German team reports that DNA methylation is altered by acute stress, thereby affecting the activity of genes.
DNA, the genetic material of cells, directs the construction of proteins. Epigenetic information is thought to direct which genes are read, acting quasi as a biological switch. An example of such a switch is provided by methyl (CH3) groups that attach to specific sections of the DNA and can remain there for a long time - even when the cell divides. Previous studies have shown that stressful experiences and psychological trauma in early life are associated with long-term altered DNA methylation. Gunther Meinlschmidt, from the Ruhr-Universitat Bochum (Germany), and colleagues examined two genes: the gene for the oxytocin receptor, i.e. the docking site for the neurotransmitter oxytocin, which has become known as the "trust hormone" or "anti-stress hormone"; and the gene for the nerve growth factor Brain-Derived Neurotrophic Factor (BDNF), which is mainly responsible for the development and cross-linking of brain cells. The researchers tested 76 people who had to participate in a fictitious job interview and solve arithmetic problems under observation - a proven means for inducing acute stress in an experiment. For the analysis of the DNA methylation, they took blood samples from the subjects before the test as well as ten and ninety minutes afterwards. Stress had no effect on the methylation of the BDNF gene. In a section of the oxytocin receptor gene, however, methylation already increased within the first ten minutes of the stressful situation. This suggests that the cells formed less oxytocin receptors. Ninety minutes after the stress test, the methylation dropped below the original level before the test. This suggests that the receptor production was excessively stimulated. The study authors submit that: “This may enhance the understanding of how psychosocial events alter DNA methylation and could provide new insights into the etiology of mental disorders.”
E Unternaehrer, P Luers, J Mill, E Dempster, A H Meyer, G Meinlschmidt, et al. “Dynamic changes in DNA methylation of stress-associated genes (OXTR, BDNF ) after acute psychosocial stress.” Translational Psychiatry 2, e150, 14 August 2012.