Poly (ADP-Ribose) Polymerase-1 (PARP-1) Induction by Cocaine Is Post-Transcriptionally Regulated by miR-125b

eNeuro. 2017 Aug 18;4(4):ENEURO.0089-17.2017. doi: 10.1523/ENEURO.0089-17.2017. eCollection 2017 Jul-Aug.


Cocaine exposure alters gene expression in the brain via methylation and acetylation of histones along with methylation of DNA. Recently, poly (ADP-ribose) polymerase-1 (PARP-1) catalyzed PARylation has been reported as an important regulator of cocaine-mediated gene expression. In this study, we report that the cellular microRNA "miR-125b" plays a key role for cocaine-induced PARP-1 expression. Acute and chronic cocaine exposure resulted in the downregulation of miR-125b concurrent with upregulation of PARP-1 in dopaminergic neuronal cells and nucleus accumbens (NAc) of mice but not in the medial prefrontal cortex (PFC) or ventral tegmental area (VTA). In silico analysis predicted a binding site of miR-125b in a conserved 3'-untranslated region (3'UTR) of the PARP-1 mRNA. Knockdown and overexpression studies showed that miR-125b levels negatively correlate with PARP-1 protein expression. Luciferase reporter assay using a vector containing the 3'UTR of PARP-1 mRNA confirmed regulation of PARP-1 by miR-125b. Specific nucleotide mutations within the binding site abrogated miR-125b's regulatory effect on PARP-1 3'UTR. Finally, we established that downregulation of miR-125b and concurrent upregulation of PARP-1 is dependent on binding of cocaine to the dopamine transporter (DAT). Collectively, these results identify miR-125b as a post-transcriptional regulator of PARP-1 expression and establish a novel mechanism underlying the molecular effects of cocaine action.

Keywords: PARP-1; PARylation; cocaine; miRNA; post-transcriptional regulation.

Publication types

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

MeSH terms

  • Animals
  • Annexin A5 / metabolism
  • Apoptosis / drug effects
  • Apoptosis / physiology
  • Brain / drug effects*
  • Brain / metabolism
  • Cattle
  • Cell Line, Tumor
  • Cocaine / pharmacology*
  • Dopamine Plasma Membrane Transport Proteins / genetics
  • Dopamine Plasma Membrane Transport Proteins / metabolism
  • Dopamine Uptake Inhibitors / pharmacology*
  • Dopaminergic Neurons / drug effects
  • Dopaminergic Neurons / metabolism
  • Enzyme Activation / drug effects
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / metabolism*
  • Neuroblastoma / pathology
  • Poly (ADP-Ribose) Polymerase-1 / metabolism*
  • Protein Binding / drug effects
  • Protein Binding / genetics
  • Rats
  • Tyrosine 3-Monooxygenase / metabolism


  • Annexin A5
  • Dopamine Plasma Membrane Transport Proteins
  • Dopamine Uptake Inhibitors
  • MIRN125 microRNA, human
  • MicroRNAs
  • Tyrosine 3-Monooxygenase
  • Poly (ADP-Ribose) Polymerase-1
  • Cocaine