Acute Stress Alters Control of Gene Activity

Drawing

In stressful social situations, the
methylation patterns (bright
spheres) of the DNA change;
© Christoph Unternährer

“The results provide evidence how stress could be related to a higher risk of mental or physical illness”, says Professor Gunther Meinlschmidt. The team looked at gene segments which are relevant to biological stress regulation.

Our genetic material, the DNA, provides the construction manual for the proteins that our bodies need. Which proteins a cell produces depends on the cell type and the environment. So-termed epigenetic information determines 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. Whether the DNA methylation also changes after acute psychosocial stress, was, however, previously unknown.

To clarify this issue, the research group examined two genes in particular: 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.

MEDICA.de; Source: Ruhr-Universität Bochum