Region-specific alterations in the corticotropin-releasing factor and glucocorticoid receptors in the postmortem brain of suicide victims

Rationale: Abnormalities of hypothalamic–pituitary–adrenal (HPA) axis in depression and suicide are among the most consistent findings in biological psychiatry. However, the specific molecular mechanism associated with HPA axis abnormality in the brain of depressed or suicidal subjects is not clear. It is believed that abnormal HPA axis is caused by increased levels of corticotropin-releasing factor (CRF) and decreased levels of glucocorticoid receptor (GR) in the brain of depressed or suicide subjects. To study their role in teenage suicide, we determined the protein and gene expression of CRF, CRF receptors, and GR in the prefrontal cortex (PFC), hippocampus, and amygdala of teenage suicide victims and teenage normal control subjects. Methods: The postmortem brain samples were obtained from the Maryland Brain Collection at the Maryland Psychiatric Research Center, Baltimore, MD, USA. Samples were obtained from 24 teenage suicide victims and 24 normal teenage control subjects. Psychological autopsy was performed and the subjects were diagnosed according to the DSM-IV (SCID). Protein expression was determined using Western blot and gene expression (mRNA) was determined using real-time RT-polymerase chain reaction (qPCR) technique. Results: We observed that the protein and gene expression of the CRF was significantly increased in the PFC (Brodmann area 9) and in amygdala, but not in the hippocampus, of teenage suicide victims compared with normal control subjects. The protein and gene expression of CRF-R1 was significantly decreased in the PFC and amygdala, but not in the hippocampus, of suicide victims. We also observed a significant decrease in the protein and mRNA expression of GR in the PFC and amygdala, but not in the hippocampus, of teenage suicide victims compared with control subjects. Conclusion: These results thus indicate that suicidal behavior is associated with increased CRF and decreased GR in certain specific areas of the brain of suicide victims compared with controls.

Abstract licence: CC BY-NC

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