title: microRNA-206 in rat medial prefrontal cortex regulates BDNF expression and alcohol drinking.
abstract: Escalation of voluntary alcohol consumption is a hallmark of alcoholism, but its neural substrates remain unknown. In rats, escalation occurs following prolonged exposure to cycles of alcohol intoxication, and is associated with persistent, wide-ranging changes in gene expression within the medial prefrontal cortex (mPFC). Here, we examined whether induction of microRNA (miR) 206 in mPFC contributes to escalated alcohol consumption. Following up on a microarray screen, quantitative real-time reverse transcription PCR (qPCR) confirmed that a history of dependence results in persistent (>3weeks) up-regulation of miR-206 expression in the mPFC, but not in the ventral tegmental area, amygdala, or nucleus accumbens. Viral-mediated overexpression of miR-206 in the mPFC of nondependent rats reproduced the escalation of alcohol self-administration seen following a history of dependence and significantly inhibited BDNF expression. Bioinformatic analysis identified three conserved target sites for miR-206 in the 3'-UTR of the rat BDNF transcript. Accordingly, BDNF was downregulated in post-dependent rats on microarray analysis, and this was confirmed by qPCR. In vitro, BDNF expression was repressed by miR-206 but not miR-9 in a 3'-UTR reporter assay, confirming BDNF as a functional target of miR-206. Mutation analysis showed that repression was dependent on the presence of all three miR-206 target sites in the BDNF 3'-UTR. Inhibition of miR-206 expression in differentiated rat cortical primary neurons significantly increased secreted levels of BDNF. In conclusion, recruitment of miR-206 in the mPFC contributes to escalated alcohol consumption following a history of dependence, with BDNF as a possible mediator of its action.
authors.affiliation: Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Jenica D
authors.initials: JD
authors.lastname: Tapocik
authors.forename: Estelle
authors.initials: E
authors.lastname: Barbier
authors.forename: Meghan
authors.initials: M
authors.lastname: Flanigan
authors.forename: Matthew
authors.initials: M
authors.lastname: Solomon
authors.forename: Alexandra
authors.initials: A
authors.lastname: Pincus
authors.forename: Andrew
authors.initials: A
authors.lastname: Pilling
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.forename: Jesse R
authors.initials: JR
authors.lastname: Schank
authors.forename: Courtney
authors.initials: C
authors.lastname: King
authors.forename: Markus
authors.initials: M
authors.lastname: Heilig
mesh_terms: D000428:Alcohol Drinking / Q000097:blood / Q000473:pathology*; D000438:Alcohols / Q000008:administration & dosage / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000378:metabolism; D017397:Prefrontal Cortex / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012646:Self Administration; D013997:Time Factors; D014161:Transduction, Genetic
chemical_list: D000438:Alcohols; D019208:Brain-Derived Neurotrophic Factor; D035683:MicroRNAs; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins
keywords: BDNF; addiction; alcohol dependence; medial prefrontal cortex; microRNA; self-administration