Genome-Wide DNA Methylation Profiling Reveals Epigenetic Changes in the Rat Nucleus Accumbens Associated With Cross-Generational Effects of Adolescent THC Exposure

Neuropsychopharmacology. 2015 Dec;40(13):2993-3005. doi: 10.1038/npp.2015.155. Epub 2015 Jun 5.


Drug exposure during critical periods of development is known to have lasting effects, increasing one's risk for developing mental health disorders. Emerging evidence has also indicated the possibility for drug exposure to even impact subsequent generations. Our previous work demonstrated that adolescent exposure to Δ(9)-tetrahydrocannabinol (THC), the main psychoactive component of marijuana (Cannabis sativa), in a Long-Evans rat model affects reward-related behavior and gene regulation in the subsequent (F1) generation unexposed to the drug. Questions, however, remained regarding potential epigenetic consequences. In the current study, using the same rat model, we employed Enhanced Reduced Representation Bisulfite Sequencing to interrogate the epigenome of the nucleus accumbens, a key brain area involved in reward processing. This analysis compared 16 animals with parental THC exposure and 16 without to characterize relevant systems-level changes in DNA methylation. We identified 1027 differentially methylated regions (DMRs) associated with parental THC exposure in F1 adults, each represented by multiple CpGs. These DMRs fell predominantly within introns, exons, and intergenic intervals, while showing a significant depletion in gene promoters. From these, we identified a network of DMR-associated genes involved in glutamatergic synaptic regulation, which also exhibited altered mRNA expression in the nucleus accumbens. These data provide novel insight into drug-related cross-generational epigenetic effects, and serve as a useful resource for investigators to explore novel neurobiological systems underlying drug abuse vulnerability.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • DNA Methylation / drug effects*
  • DNA Methylation / physiology
  • Dronabinol / toxicity*
  • Epigenesis, Genetic / drug effects*
  • Epigenesis, Genetic / physiology
  • Female
  • Male
  • Maternal Exposure / adverse effects
  • Nucleus Accumbens / drug effects*
  • Nucleus Accumbens / metabolism*
  • Paternal Exposure / adverse effects
  • Promoter Regions, Genetic
  • Psychotropic Drugs / toxicity*
  • RNA, Messenger / metabolism
  • Rats, Long-Evans
  • Reverse Transcriptase Polymerase Chain Reaction


  • Psychotropic Drugs
  • RNA, Messenger
  • Dronabinol