Early stress increased the level of the enzyme SETD7 in dopamine cells in the brain's reward region, leaving genes related to the stress response more available for activation. Blocking the process reduced later stress sensitivity – but it is not yet known whether the mechanism works this way in humans
Children exposed to severe adversity are at increased risk of developing anxiety disorders, depression, and other stress-related problems in adulthood. A new study in mice suggests a possible biological mechanism for this phenomenon: Early-life stress changes the way DNA is packaged in cells dopamine certain areas of the brain, thus leaving genes related to the stress response more available for activation in the future.
The researchers from Princeton University and Washington University School of Medicine in St. Louis describe the change as a kind of “molecular memory” or epigenetic “scar.” However, it is not a change in the DNA sequence itself, and the study does not prove that this mechanism works in the same way in humans.
The study was published on August 7, 2026, in the journal Neuron.
Memory that does not change the DNA sequence
The genetic material in a cell is not laid out as an open thread. The DNA is wrapped around proteins called histones, forming a structure called ChromatinWhen chromatin is compacted, it is more difficult for the cell's machinery to reach and activate genes. When the packaging is looser, genes become accessible for activation.
Chemical changes to DNA or the proteins around it can affect gene activity without changing the genetic sequence of letters. Such changes are called epigenetic. They allow cells to respond to the environment, development, nutrition, and different experiences.
In the current study, the researchers found that stress at a young age caused the accumulation of a chemical marker called H3K4me1 in the chromatin of certain brain cells. The marking does not necessarily turn on the genes immediately, but it leaves certain regions of the chromatin in a more accessible state. As a result, the genes may respond more strongly to additional stress in adulthood.
Focusing on dopamine cells
The researchers focused on the ventral tegmental area, known by the acronym VTA. This is a deep region of the brain that contains many cells that produce dopamine, a neurotransmitter involved in, among other things, motivation, reward, learning, and coping with emotionally significant events.
Abnormal activity of dopamine cells in this area has been linked in previous studies to mood disorders, addiction, and changes in the way we think. the brain responds to reward and distress. Therefore, the researchers wanted to test whether Early stress Leaves a lasting change in these cells.
Mice exposed to stress at a young age had higher levels of the enzyme SETD7 In dopamine cells in the VTA. The enzyme helps attach the H3K4me1 mark to histone proteins. The accumulation of the mark made areas of chromatin more open and accessible.
The researchers found that in the VTA, the SETD7 enzyme appeared almost exclusively in dopamine cells, a finding that strengthened the possibility that these cells play a direct role in creating the heightened sensitivity to stress.
Amplification and inhibition of SETD7
To test whether SETD7 is just a marker of stress or an active factor in the process, the researchers developed genetic tools that allowed them to change the level of the enzyme in the VTA of young mice.
In the first step, they artificially increased the level of SETD7 in young mice that had not previously been exposed to stress. When the mice grew older and were exposed to stressful events, they showed increased sensitivity: their dopamine cells became more reactive, and in behavioral tests, more anxiety-like behaviors and less social interaction were observed.
In another step, the researchers blocked SETD7 activity in mice exposed to early stress. The blockade prevented the excessive accumulation of H3K4me1 and reduced the changes seen in adulthood. The mice remained more social and exploratory, and their dopamine cell activity was more similar to that of mice not exposed to early stress.
The results suggest a possible causal relationship: increasing the level of SETD7 was sufficient to increase late sensitivity to stress, while reducing its activity reduced it.
The brain is primed for a strong response.
Elevating SETD7 did not cause dopamine cells to fire at an abnormally high intensity all the time. The difference became clear after the mice were exposed to additional stress in adulthood. That is, the epigenetic change did not necessarily create an immediate disruption, but rather prepared the cells to respond more strongly to a future event.
This finding may explain why the effects of difficult experiences at a young age do not always appear immediately. A person can function for years, but become more vulnerable when they encounter additional periods of stress, loss, or uncertainty.
However, comparisons to humans are limited. Behavioral tests in mice are not diagnostic of anxiety or depression, and complex human experiences cannot be fully reproduced in a laboratory animal model.
There is still no treatment designed for humans.
The ability to reduce the effect of SETD7 in mice raises the possibility that the enzyme or the H3K4me1 mark could be used as a target for future drug research. However, the study does not offer a ready-made treatment and does not show that blocking the enzyme in humans is safe or desirable.
SETD7 and epigenetic marks participate in many processes in the body. Intervening in them may also affect systems unrelated to stress. It will first be necessary to examine whether the same mechanism exists in human brain cells, whether it operates during similar developmental periods, and whether it can be influenced in a targeted and safe manner.
The study also does not say that difficult childhood experiences necessarily determine a person's future. Risk is influenced by many factors, including heredity, type of experience, duration, age of exposure, family and social support, and later experiences.
According to the researchers, support, care, and social resources during sensitive periods may help the developing brain build resilience. The possibility that epigenetic changes increase sensitivity need not only work in a negative direction: a more sensitive brain may also respond strongly to a beneficial environment and positive experiences.
Questions and Answers
Was the study conducted on humans?
No. The study was conducted in laboratory mice. It suggests a possible mechanism linking early stress to later stress sensitivity, but it remains to be seen whether a similar mechanism exists in humans.
Does childhood stress cause a genetic mutation?
No. The researchers found an epigenetic change that affects the packaging of DNA and the accessibility of genes for activation. The DNA sequence itself did not change.
What is the role of the enzyme SETD7?
SETD7 helps attach the H3K4me1 mark to the histone proteins around which DNA is wrapped. The study found that increased levels of it in certain dopamine cells left stress-related genes more accessible for activation.
Could blocking SETD7 be used as a treatment?
Not yet. The blockage has been tested using experimental tools in mice. Much more research is needed before we can know if this is a safe and effective therapeutic target for humans.
For the original publication: Opening the original publication
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