Proteomic profiling of postmortem prefrontal cortex tissue of suicide completers

A total of 36 postmortem brain samples (23 suicide completers, 13 control sudden death) were collected. We evaluated the proteome profile in the prefrontal cortex (Brodmann area 9, 10) with TMT-based quantification using LC-MS/MS. Several bioinformatics tools were used to elucidate biological mechanisms related to suicide. Subgroup analysis was conducted to find common differentially expressed proteins (DEPs) among various clinically different groups. Among the 9801 proteins identified in our dataset, 295 proteins were differentially expressed between suicide completers and sudden death subjects. Various bioinformatics analysis revealed that suicide completion is predominately enriched in synaptic functions and synaptogenesis especially in endocannabinoid and GABA signaling pathway. Our finding presents the largest protein pools related to suicide completion, and suggests that newly emerging neurotransmitter systems such as endocannabinoid system and synaptogenesis processes may have an impact upon the biological cascade leading to suicide.