Genome-wide DNA methylation profile in the peripheral blood of cocaine and crack dependents

OBJECTIVE: Cocaine use disorders (CUDs) represent a major public health problem in many countries. To better understand the interaction between the environmental modulations and phenotype, the aim of the present study was to investigate the DNA methylation pattern of CUD patients, who had concomitant cocaine and crack dependence, and healthy controls. METHODS: We studied DNA methylation profiles in the peripheral blood of 23 CUD patients and 24 healthy control subjects using the Illumina Infinium HumanMethylation450 BeadChip arrays. RESULTS: Comparison between CUD patients and controls revealed 186 differentially methylated positions (DMPs; adjusted p-value [adjP] < 10(-5)) related to 152 genes, with a subset of CpGs confirmed by pyrosequencing. DNA methylation patterns discriminated CUD patients and control groups. A gene network approach showed that the EHMT1, EHMT2, MAPK1, MAPK3, MAP2K1, and HDAC5 genes, which are involved in transcription and chromatin regulation cellular signaling pathways, were also associated with cocaine dependence. CONCLUSION: The investigation of DNA methylation patterns may contribute to a better understanding of the biological mechanisms involved in CUD.