title: miR-203 regulates nociceptive sensitization after incision by controlling phospholipase A2 activating protein expression.
abstract: BACKGROUND
  After incision keratinocytes in the epidermis become activated to produce a range of pain-related mediators. microRNA 203 (miR-203) is known to be involved in keratinocyte growth, differentiation, and skin inflammation. We hypothesized that one or more of these mediators might be under the control of miR-203.
  
  
  METHODS
  The expression of miR-203 and its target gene, phospholipase A2 activating protein (PLAA), were examined after hind paw incision in mice. We investigated the local effect of intraplantar PLAA peptide injection in normal mice and the effects of a selective secretory phospholipase A2 inhibitor (HK064) on PLAA or incision-induced mechanical allodynia. Last, we investigated the role of substance P signaling in regulating miR-203 and PLAA expression in vitro and in vivo.
  
  
  RESULTS
  Levels of miR-203 were strongly down-regulated in keratinocytes after incision. Informatics-based approaches identified PLAA as a likely candidate for regulation by miR-203. PLAA caused mechanical allodynia and conditioned place aversion but not thermal sensitization. HK064 reduced mechanical allodynia after incision and after intraplantar injection of PLAA. Using preprotachykinin gene knockout mice or with neurokinin-1 selective antagonist LY303870 treatment, we observed that substance P-mediated signaling was also required for miR-203 and PLAA regulation after incision. Finally, using the rat epidermal keratinocyte cell line, we observed that a miR-203 mimic molecule could block the substance P-induced increase in PLAA expression observed under control conditions.
  
  
  CONCLUSIONS
  miR-203 may regulate expression of the novel nociceptive mediator PLAA after incision. Furthermore, the regulation of miR-203 and PLAA levels is reliant upon intact substance P signaling.
authors: Department of Anesthesiology, Stanford University School of Medicine, Stanford, California, USA.
authors: Yuan
authors: Y
authors: Sun
authors: Xiang-Qi
authors: XQ
authors: Li
authors: Peyman
authors: P
authors: Sahbaie
authors: Xiao-You
authors: XY
authors: Shi
authors: Wen-Wu
authors: WW
authors: Li
authors: De-Yong
authors: DY
authors: Liang
authors: J David
authors: JD
authors: Clark
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D011498:Protein Precursors / Q000502:physiology; D011506:Proteins / Q000502:physiology*; D018040:Receptors, Neurokinin-1 / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013373:Substance P / Q000502:physiology; D015320:Tachykinins / Q000502:physiology
chemical_list: C575934:MIRN203 microRNA, mouse; D035683:MicroRNAs; D011498:Protein Precursors; D011506:Proteins; D018040:Receptors, Neurokinin-1; D015320:Tachykinins; C055324:phospholipase A2-activating protein; C044206:preprotachykinin; D013373:Substance P