How early-life stress leaves a 'scar' inside brain cells
Experiencing severe stress during childhood can make a person more vulnerable to anxiety, depression and other mood disorders when faced with hardships as an adult. Researchers at Washington University School of Medicine in St. Louis and Princeton University have uncovered how trauma early in life can leave a lasting effect on the brain.
Early-life stress can leave lasting damage to brain cells, making individuals more susceptible to anxiety and depression later in life. Researchers at Washington University School of Medicine and Princeton University have discovered that this impact is due to alterations in how brain cells package DNA.
When stress occurs during childhood, it triggers changes in the activity of genes in the brain. Specifically, an enzyme called SETD7 becomes more abundant in dopamine-producing neurons of young mice that have experienced stress. SETD7 helps place a chemical tag on the DNA, loosening the coil and making the genes more accessible for activation.
Mice with artificially boosted SETD7 levels, even without early-life stress, exhibited a stretch-open DNA structure in their dopamine-producing brain cells, making them more reactive to stressors. These mice displayed lower tolerance for stress as adults.
Conversely, blocking the SETD7 enzyme from adding too many H3K4me1 tags after early-life stress prevented the DNA from loosening, protecting mice from becoming hypersensitive to stress later in life. When the SETD7 levels were dampened despite both early-life and adult stress, mice remained social and exploratory, with normal dopamine neuron activity.
This study reveals a clear mechanism behind the impact of early-life stress on the brain and provides a potential target for developing new treatments and interventions to prevent long-term mental and physical health challenges.
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