Researchers at Yale University in the USA may have found an explanation for why
patients with severe depression often show decreased volume of certain
areas of the brain.
Their study, published in the journal Nature Medicine, identified a genetic 'switch'
- a transcription factor - which regulates several genes related to the
communication between neurons. This transcription factor, called GATA1, appears
to be overproduced in depressed patients, say the scientists.
Senior author Professor Ronald Duman said the team 'wanted to test the idea
that stress causes a loss of brain synapses in humans'. Synapses are the
interfaces where two or more brain cells communicate. He says the study shows that
'circuits normally involved in emotion, as well as cognition, are disrupted
when this single transcription factor is activated'.
The researchers analysed post-mortem brain tissue of depressed and non-depressed
people donated from a brain bank. They found lower expressions of several genes
related to synaptic function, as well as fewer synapses, in a frontal region
of the brain of depressed people. They also found that the transcriptional
factor GATA1 was up-regulated in the depression group.
To test the relationship between GATA1 and brain volume, the scientists activated
the transcription factor in the frontal brain region of rats. Doing so led to a
decrease in expression of genes related to synapse function, causing the loss
of connection points between neurons. Also, the rodents started to display
depressive behaviour.
A link between the structural changes of the frontal brain region in
depressed patients and biological mechanisms needs further corroboration. The Yale
researchers believe the observed damage could be a result of chronic stress and
hope that their findings will lead to new treatments against depression.
'We hope that by enhancing synaptic connections, either with novel
medications or behavioural therapy, we can develop more effective
antidepressant therapies', said Professor Duman.
Related Articles
Depression may speed up DNA ageing
Severe depression speeds up the ageing process of our cells, researchers have found...
Body clock genes linked to depression
Genes believed to regulate sleep rhythm are expressed abnormally in people with major depressive disorders, scientists say...
Risk of teenage depression affected by genes
The risk of depression in adolescents exposed to negative environments during their childhood is partly dependent on their genetic make-up, suggest researchers...
Gene linked to obesity also associated with depression
A gene linked to obesity may also provide protection from major depression, say scientists...
Genes and depression, researchers find new region of interest
Scientists believe they have identified a new genetic link to severe depression....
Post-traumatic stress disorder risk may be partly genetic
A new study has demonstrated that levels of a hormone involved in the response to stress could explain why some people develop post-traumatic stress disorder (PTSD). The research, conducted by scientists at Emory University and the University of Vermont in the US, studied a group of patients considered at high-risk of developing PTSD...
Miserable? It's in your genes, study claims
US researchers have found a correlation between levels of the brain chemical neuropeptide Y (NPY) and an individual's emotional wellbeing. Mutations in the NPY gene, leading to decreased levels of the molecule, correlated with a decreased ability to deal with stressful situations and an increased susceptibility to depression....
Gene variant provides clues to mental illness
Researchers at the University of Edinburgh, Scotland, have identified a gene that may be involved in mental illness and maintaining brain health. The scientists compared the genes of 2,000 psychiatric patients and 2,000 healthy people in Scotland. They discovered that the ABCA13 gene was faulty more frequently in patients with severe mental illness - such as schizophrenia, bipolar disorder and depression - than in the healthy control group....
Gene link to depression under question
A new study published in the Journal of the American Medical Association has called into question a previously reported link between a gene variation and risk of depression. The study, funded by the National Institute of Mental Health (NIMH) and carried out by scientists from six US universities, was led by Dr Kathleen Merikangas from the NIMH Intramural Research program and Dr Neil Risch of the University of California, San Francisco....
Leave a Reply
You must be logged in to post a comment.