Health and Fitness.---Discovery.

Key depression gene discovered

[Posted: Mon 18/10/2010 by Deborah Condon - www.irishhealth.com]

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Scientists have discovered a gene that appears to play a key role in the onset of depression and may therefore prove a promising target for a new class of antidepressants.
An estimated 280,000 people in Ireland have depression at any one time. However symptoms can wary widely among individuals and researchers have had a difficult time pinning down the cause of the condition.


It is now widely acknowledged that multiple physiological processes are involved in cases of major depression. This explains why people respond differently to most commonly prescribed antidepressants, which work by manipulating the uptake of the neurotransmitter serotonin.
Neurotransmitters are chemical messengers in the brain. Serotonin is one of the key neurotransmitters. When these behave normally, mood is regulated. However, if these neurotransmitters are not moving freely as they should, depression occurs.
As many as 40% of depressed patients do not respond to currently available medications, which take weeks or months to produce a therapeutic response.


Researchers at Yale University in the US carried out whole genome scans on tissue samples from 21 deceased people who had been diagnosed with depression when they were alive. Their gene expression levels were compared to those of 18 individuals who had not been diagnosed with depression.


The researchers found that one gene called MKP-1 was increased more than two-fold in the brain tissues of depressed people.


This is particularly interesting, according to the team, because the gene inactivates a molecular pathway crucial to the survival and function of neurons (nerve cells) and its impairment has been implicated in depression as well as other disorders.


The researchers also found that when the MKP-1 gene is knocked out in mice, the mice become resilient to stress. When the gene is activated, mice exhibit symptoms that mimic depression.


"This could be a primary cause, or at least a major contributing factor, to the signaling abnormalities that lead to depression," said the study's lead author, Prof Ronald Duman.
He added that MKP-1 could also be a potential target for a new class of drugs, particularly in relation to treatment-resistant depression.


Details of these findings are published in the journal, Nature Medicine.
(irishhealth)
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