Severe stress during childhood can increase a person's vulnerability to anxiety, depression, and other mood disorders when new challenges arise later in life. Scientists at Washington University School of Medicine in St. Louis and Princeton University have now identified a biological process that may help explain how early trauma can have such long-lasting effects on the brain.
Researchers have known that stress during early development can alter gene activity in the brain. The new findings suggest that these changes stem partly from the way brain cells package their DNA. By making certain stress-related genes easier to activate, early adversity may leave the brain more reactive and less able to tolerate future stress.
The study was published Aug. 7 in Neuron. "We have uncovered a new biological process linking experience of early-life adversity to this long-term vulnerability to mental illness," said Meaghan Creed, PhD, an associate professor of anesthesiology at WashU Medicine and the study's co-corresponding author. "This finding reveals a physical scar left by trauma experienced during development inside brain cells, providing scientists with a concrete biological target to develop new treatments and interventions." How Childhood Stress Changes DNA Packaging More than half of children worldwide experience some form of early-life stress, including abuse, violence, or drug use within the household, and other traumatic events.
Experiencing four or more of these adverse events is associated with a sharply higher risk of physical and mental health problems later in life. To understand how these experiences can physically alter the developing brain, the researchers focused on the ventral tegmental area. This brain region contains neurons that produce dopamine, a chemical messenger involved in processing important experiences, including rewards and adversity.
When stress causes these neurons to become abnormally active, reward processing can be disrupted, potentially increasing vulnerability to anxiety and depression. The team then examined the epigenome inside these dopamine-producing neurons. The epigenome consists of molecular tags that help control whether genes are switched on or off, ultimately influencing how cells behave.
Catherine Jensen Peña, PhD, an assistant professor at the Princeton Neuroscience Institute and the study's senior and co-corresponding author, compared DNA inside cells to a coiled slinky. DNA is wrapped around proteins called histones, which help control how tightly or loosely it is packed. When this genetic slinky is tightly compressed, genes are less accessible and remain switched off.
Extract — continue reading at the source.
