Psychological stress may increase the risk of mental and physical illness by altering the control of genes, according to a new study by researchers at the Ruhr-Universität Bochum (RUB).
The research, believed to be the first to show that stress alters the methylation of DNA and therefore the activity of certain genes, investigated genes already known to be involved with controlling stress.
Previous studies have shown that early psychological trauma and highly stressful events are linked to long-term methylation changes to DNA. But what researchers in this study set out to find was whether this also happens after acute psychological stress: for instance, such as that experienced during a job interview.
For the study, they looked at two genes: one for the oxytocin receptor (OXTR), and one for the nerve growth factor brain-derived neurotrophic factor (BDNF).
OXTR is a docking site for oxytocin, a chemical messenger that has been dubbed the “love” or “trust hormone.” BDNF plays an important role in the development of brain cells.
The researchers recruited 76 participants in their 60s to experience two kinds of stressful events. The first was to to take part in a mock job interview, and the other was to solve math problems while being watched. Both of these tests are common ways to produce stress under lab conditions.
The subjects gave blood samples before the tests, and also twice afterwards: one ten minutes after (post-test), and another 1.5 hours after (follow-up). From these samples, researchers could measure the amount of DNA methylation in the two genes.
The results showed that the BDNF gene was unaffected by the stress tests. However, the OXTR gene showed methylation changes. There was an increase in methylation in a section of this gene in the post-test measure — this suggests the cells formed fewer receptors.
Then in the follow-up blood sample, 1.5 hours after the test, methylation in the OXTR gene fell below the pre-test level, which suggests that the cells produced too many receptors.
“The results suggest a dynamic regulation of DNA methylation in OXTR — which may in part reflect changes in blood cell composition — but not BDNF after acute psychosocial stress,” said the authors.
“Epigenetic changes may well be an important link between stress and chronic diseases,” said senior and corresponding author Dr. Gunther Meinlschmidt, professor and head of the Research Department of Psychobiology, Psychosomatics and Psychotherapy at the LWL University Hospital in RUB.
“We hope to identify more complex epigenetic stress patterns in future and thus to be able to determine the associated risk of disease. This could provide information on new approaches to treatment and prevention,” he added.
The research is published in the journal Translational Psychiatry.
Source: Ruhr-Universität Bochum