FENS 2018: Epigenetics – trans-generational effects of traumatic experiences

Written by Olivia Stevenson, Future Science Group

Research from the University ETH Zürich (Zürich, Switzerland), has demonstrated that traumatic experiences can lead to epigenetic modifications. These modifications can be passed down through the next few generations, potentially leading to behavioral changes and psychological disorders in the offspring of an individual who has experienced a traumatic event.
However, the results of the study also suggest that a positive and stimulating environment can correct these changes.

Traumatic or stressful experiences can have long-lasting effects on an individual and their family. Understanding how these experiences can change gene activity, and potentially be passed on to offspring, may one day be beneficial in the treatment of behavioral disorders linked to trauma.

In this study, led by Isabelle Mansuy and reported at the FENS Forum of Neuroscience (7–11 July, Berlin, Germany), the researchers examined whether the impacts of trauma could be passed down through generations in mice. In early life, male and female mice underwent separation from their mothers for prolonged or erratic periods of time. The researchers then tested the impact of this trauma in the next four generations of mice.

The researchers demonstrated that the successive generations of mice inherited the impacts of this trauma, resulting in behavioral impacts such as antisocial behavior and depressive-like symptoms. The impact of trauma is not solely limited to the brain however, and the researchers also found that blood and germ cells can be affected in this way.

When epigenetic changes occur, chemical modifications – known as methyl groups – attach to DNA. Other modifications can also be added to histones. This means that even though the genetic code has not changed, the genetic activity has been altered. These changes were detected in this study.

The team are now carrying out research into epigenetic changes in children and adults who have undergone trauma. “The results look very promising,” concluded Mansuy.

Research from the University of Linköping (Linköping, Sweden), has also been looking into the transmission and expression of behavior, and concluded that epigenetics may have contributed to the domestication of animals.

The team, led by Per Jensen (University of Linköping), established that stressful events could cause epigenetic changes in the brains of domestic and wild chickens, as well as in domestic and wild dogs.

The researchers simulated animal domestication using red junglefowl, the native equivalent of the domestic chicken. By selecting and breeding animals that were more confident around humans, the study not only demonstrated a behavioral change in the animals, but allowed researchers to measure epigenetic effects.

This new research is an important step forward in understanding how trauma and other acquired characteristics can lead to epigenetic modifications, and how stressful events can therefore have trans-generational consequences.

Sources: Mansuay I. Molecular mechanisms of germline-dependent transgenerational epigenetic inheritance. Presented at: FENS Forum of Neuroscience, Berlin, Germany, 7–11 July 2018; Jensen P. Epigenetic basis of behavioral expression and transmission in domesticated species. Presented at: FENS Forum of Neuroscience, Berlin, Germany, 7–11 July 2018.

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