Methamphetamine Induces TET1- and TET3-Dependent DNA Hydroxymethylation of Crh and Avp Genes in the Rat Nucleus Accumbens

Subramaniam Jayanthi,Veronica Bisagno,Michael T Mccoy,Bruce Ladenheim,Jean Lud Cadet,Betina Gonzalez

doi:10.1007/s12035-017-0750-9

Abstract

Methamphetamine (METH) addiction is a biopsychosocial disorder that is accompanied by multiple relapses even after prolonged abstinence, suggesting the possibilities of long-lasting maladaptive epigenetic changes in the brain. Here, we show that METH administration produced time-dependent increases in the expression of corticotropin-releasing hormone (Crh/Crf), arginine vasopressin (Avp), and cocaine- and amphetamine-regulated transcript prepropeptide (Cartpt) mRNAs in the rat nucleus accumbens (NAc). Chromatin immunoprecipitation (ChIP) assays revealed that METH increased the abundance of phosphorylated CREB (pCREB) at the promoter of Cartpt but not at Avp or Crh DNA sequences. In contrast, METH produced DNA hypomethylation at sites near the Crh transcription start site (TSS) and at intragenic Avp sequences. METH also increased DNA hydroxymethylation at the Crh TSS and at intragenic Avp sites. In addition, METH increased the protein expression of ten-eleven-translocation enzymes that catalyze DNA hydroxymethylation. Importantly, METH increased TET1 binding at the Crh promoter and increased TET3 binding at Avp intragenic regions. We further tested the role of TET enzymes in METH-induced changes in gene expression by using the TET inhibitor, 1,5-isoquinolinediol (IQD), and found that IQD blocked METH-induced increases in Crh and Avp mRNA expression. Together, these results indicate that METH produced changes in neuropeptide transcription by both activation of the cAMP/CREB pathway and stimulation of TET-dependent DNA hydroxymethylation. These results provide molecular evidence for epigenetic controls of METH-induced changes in the expression of neuropeptides.

Highlights

Methamphetamine (METH) is an addictive psychostimulant whose abuse is widespread throughout the world
Because phosphorylated CREB (pCREB) did not appear to play a role in Crh and arginine vasopressin (Avp) mRNA expression, we wondered if METH-induced DNA hypomethylation might be involved in the upregulation of these mRNAs
The present study shows that an injection of METH produced long-lasting alterations in the expression of Crh, Avp, and cocaine- and amphetamine-regulated transcript prepropeptide (Cartpt) mRNAs

Summary

Introduction

Methamphetamine (METH) is an addictive psychostimulant whose abuse is widespread throughout the world. Its rewarding properties are due to activation of the reward pathway that projects from the ventral tegmental area (VTA) to diverse brain structures including the nucleus accumbens (NAc) [1, 2] Perturbations in this pathway may be involved in promoting relapses [3]. Addiction appears to stimulate diverse pathways that may serve as a coincident signal to promote compulsive drug-taking behaviors [7, 8] Some of these pathways may use neuropeptides that are known to respond to stress, as recently described in a microarray paper that documented METHinduced increases in the expression of Crh/Crf, Avp, and Cartpt in the NAc [8].

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Conclusion