Targeted sequencing approach: Comprehensive analysis of DNA methylation and gene expression across blood and brain regions in suicide victims.

OBJECTIVES

Epigenetic mechanisms are involved in regulation of many pathologies, including suicidal behaviour. However, the factors through which epigenetics affect suicidal behaviour are not fully understood.

METHODS

We analysed DNA methylation of eight neuropsychiatric genes (1, , , 2, , , , and ) in brain regions (hippocampus, insula, amygdala, Brodmann area 46) and blood of 25 male suicide victims and 28 male control subjects, using bisulphite next-generation sequencing.

RESULTS

Comparing mean methylation values, notable changes were observed in (insula -value = 0.05), (insula -value < 0.001, blood -value = 0.001), (insula -value = 0.03, blood -value = 0.016), (blood -value < 0.001), (insula -value = 0.05, blood -value = 0.024) and (hippocampus -value = 0.001, insula -value = 0.002, amygdala -value = 0.014). Comparing methylation pattern between blood and brain, similarity was observed between blood and insula for Gene expression analysis in hippocampus revealed changes in expression of (-value = 0.049), (-value = 0.017) and (-value = 0.053).

CONCLUSIONS

Results provide an insight into the altered state of DNA methylation in suicidal behaviour. Epigenetic differences could therefore affect suicidal behaviour in both previously known and in novel neuropsychiatric candidate genes.