Traumatic events like getting picked last for Dodgeball in gym class can really mess with your head. And some previous research has shown that really devastating incidents, such as 9-11, can change us, even while still in the womb, as shown in this video clip we posted a while back from the PBS Ghost in Your Genes special. Also, as much as we hate to admit it, one benefit of exercise is that it can produce epigenetic changes that help rats cope better with stress. Now, there’s another piece of evidence linking emotions and epigenetics—researchers at the Max Planck Institute of Psychiatry have demonstrated that an early-life stress (ELS) can change the methylation patterns in the brain.
To stress out baby mice, the researchers over-worked and under-paid them, (Oh, wait. No, that’s us!) Instead, they separated them from their moms for three hours every day for their first ten days of life. These pups had high levels of arginine vasopression (AVP) mRNA, and AVP is known to have effects on mood and cognition. The baby mice also had memory problems and were less active in a forced swim test than controls. These effects went on for at least a year.
It turns out that two epigenetic mechanisms were at play:
- CpG island #3 (CGI3) in the AVP enhancer region was hypomethylated in ELS mice.
- MeCp2 can bind to CGI3 to repress transcription, but ELS results in phosphorylated MeCP2, which doesn’t bind CGI3.
So, early stress equals a lot of AVP, which equals a lot of problems. To get all the stressful details, check out Nature Neuroscience, November 2009.