Molecular 'fingerprint' for depression, anxiety found, study says


Professor Alon Chen and Dr. Orna Issler of the Weizmann Institute investigated the molecular mechanisms of the brain's serotonin system and believe they've found specific molecular markers in those suffering from depression and anxiety. Their research focused on the microRNA molecules in the nerve cells that produce serotonin. These tiny non-coding RNA molecules regulate various cellular activities and the researchers found that in those with depression or anxiety, miR135 (one of the microRNA molecules) and two proteins can affect serotonin production.

The findings were published in Neuron last month. The scientists noted an increase in miR135 molecules in serotonin-producing areas of the brain when antidepresants were introduced. After engineering mice to produce higher-than-average amounts of this microRNA, the found that they were more stress resistant, taking longer to develop chronic stress behaviors. This is in contrast to mice with low levels of the microRNA molecule, which showed higher levels of stress-related behaviors under the same pressures.

Using human blood samples, the researchers followed the rodent-based research in the lab with tests to find the markers. The miR135 levels in subjects who suffer from depression were low. Closer inspection of the genome showed that the genes which produce miR135 are located in the same areas as those known to be associated with risks for bipolar disorders.

Professor Chen believes that this molecule could become a blood test for depression and related disorders and as a target for further pharmaceutical research.


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