Decreased microRNA-125a-3p contributes to upregulation of p38 MAPK in rat trigeminal ganglions with orofacial inflammatory pain

PLoS One. 2014 Nov 7;9(11):e111594. doi: 10.1371/journal.pone.0111594. eCollection 2014.

Abstract

Orofacial inflammatory pain is a difficult clinical problem, and the specific molecular mechanisms for this pain remain largely unexplained. The present study aimed to determine the differential expression of microRNAs (miRNAs) and disclose the underlying role of miR-125a-3p in orofacial inflammatory pain induced by complete Freund's adjuvant (CFA). Thirty-two differentially expressed miRNAs were first screened using a microarray chip in ipsilateral trigeminal ganglions (TGs) following CFA injection into the orofacial skin innervated by trigeminal nerve, and a portion of them, including miR-23a*, -24-2*, -26a, -92a, -125a-3p, -183 and -299 were subsequently selected and validated by qPCR. The target genes were predicted based on the miRWalk website and were further analyzed by gene ontology (GO). Further studies revealed miR-125a-3p expression was down-regulated, whereas both the expression of p38 MAPK (mitogen-activated protein kinase) alpha and CGRP (calcitonin gene-related peptide) were up-regulated in ipsilateral TGs at different time points after CFA injection compared with control. Furthermore, mechanistic study revealed that miR-125a-3p negatively regulates p38 alpha gene expression and is positively correlated with the head withdrawal threshold reflecting pain. Luciferase assay showed that binding of miR-125a-3p to the 3'UTR of p38 alpha gene suppressed the transcriptional activity, and overexpression of miR-125a-3p significantly inhibited the p38 alpha mRNA level in ND8/34 cells. Taken together, our results show that miR-125a-3p is negatively correlated with the development and maintenance of orofacial inflammatory pain via regulating p38 MAPK.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Behavior, Animal / drug effects
  • Calcitonin Gene-Related Peptide / genetics
  • Facial Pain / enzymology
  • Facial Pain / genetics*
  • Facial Pain / metabolism*
  • Facial Pain / pathology
  • Freund's Adjuvant / pharmacology
  • Gene Ontology
  • Inflammation / enzymology
  • Inflammation / genetics
  • Inflammation / metabolism
  • Inflammation / pathology
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects
  • Trigeminal Ganglion / drug effects
  • Trigeminal Ganglion / enzymology
  • Trigeminal Ganglion / metabolism*
  • Up-Regulation / drug effects
  • Up-Regulation / genetics*
  • p38 Mitogen-Activated Protein Kinases / genetics*

Substances

  • MIRN125 microRNA, rat
  • MicroRNAs
  • Freund's Adjuvant
  • p38 Mitogen-Activated Protein Kinases
  • Calcitonin Gene-Related Peptide

Grant support

The work was supported by National Natural Science Foundation of China (No. 81100768, 81072213 and No. 81171659), Jiangsu Government Scholarship for Overseas Studies, Key Project supported by Medical Science and Technology Development Foundation, Nanjing Department of Health (No. YKK11040; YKK09124; YKK13145; QRX11123) and Jiangsu Health International Exchange Program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.