title: NOV/CCN3 attenuates inflammatory pain through regulation of matrix metalloproteinases-2 and -9.
abstract: BACKGROUND
  Sustained neuroinflammation strongly contributes to the pathogenesis of pain. The clinical challenge of chronic pain relief led to the identification of molecules such as cytokines, chemokines and more recently matrix metalloproteinases (MMPs) as putative therapeutic targets. Evidence points to a founder member of the matricial CCN family, NOV/CCN3, as a modulator of these inflammatory mediators. We thus investigated the possible involvement of NOV in a preclinical model of persistent inflammatory pain.
  
  
  METHODS
  We used the complete Freund's adjuvant (CFA)-induced model of persistent inflammatory pain and cultured primary sensory neurons for in vitro experiments. The mRNA expression of NOV and pro-inflammatory factors were measured with real-time quantitative PCR, CCL2 protein expression was assessed using ELISA, MMP-2 and -9 activities using zymography. The effect of drugs on tactile allodynia was evaluated by the von Frey test.
  
  
  RESULTS
  NOV was expressed in neurons of both dorsal root ganglia (DRG) and dorsal horn of the spinal cord (DHSC). After intraplantar CFA injection, NOV levels were transiently and persistently down-regulated in the DRG and DHSC, respectively, occurring at the maintenance phase of pain (15 days). NOV-reduced expression was restored after treatment of CFA rats with dexamethasone. In vitro, results based on cultured DRG neurons showed that siRNA-mediated inhibition of NOV enhanced IL-1β- and TNF-α-induced MMP-2, MMP-9 and CCL2 expression whereas NOV addition inhibited TNF-α-induced MMP-9 expression through β1 integrin engagement. In vivo, the intrathecal delivery of MMP-9 inhibitor attenuated mechanical allodynia of CFA rats. Importantly, intrathecal administration of NOV siRNA specifically led to an up-regulation of MMP-9 in the DRG and MMP-2 in the DHSC concomitant with increased mechanical allodynia. Finally, NOV intrathecal treatment specifically abolished the induction of MMP-9 in the DRG and, MMP-9 and MMP-2 in the DHSC of CFA rats. This inhibitory effect on MMP is associated with reduced mechanical allodynia.
  
  
  CONCLUSIONS
  This study identifies NOV as a new actor against inflammatory pain through regulation of MMPs thus uncovering NOV as an attractive candidate for therapeutic improvement in pain relief.
authors.affiliation: INSERM UMR_S 938, Centre de Recherche de Saint-Antoine, Hôpital Saint-Antoine, Paris F-75012, France.
authors.forename: Lara
authors.initials: L
authors.lastname: Kular
authors.forename: Cyril
authors.initials: C
authors.lastname: Rivat
authors.forename: Brigitte
authors.initials: B
authors.lastname: Lelongt
authors.forename: Claire
authors.initials: C
authors.lastname: Calmel
authors.forename: Maryvonne
authors.initials: M
authors.lastname: Laurent
authors.forename: Michel
authors.initials: M
authors.lastname: Pohl
authors.forename: Patrick
authors.initials: P
authors.lastname: Kitabgi
authors.forename: Stéphane
authors.initials: S
authors.lastname: Melik-Parsadaniantz
authors.forename: Cécile
authors.initials: C
authors.lastname: Martinerie
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology / Q000627:therapeutic use; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005620:Freund's Adjuvant; D005727:Ganglia, Spinal / Q000166:cytology; D005786:Gene Expression Regulation / Q000187:drug effects; D006930:Hyperalgesia / Q000139:chemically induced / Q000188:drug therapy; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D007249:Inflammation / Q000139:chemically induced / Q000150:complications*; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010146:Pain / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D011984:Sensory Receptor Cells / Q000187:drug effects; D013116:Spinal Cord / Q000473:pathology; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000893:Anti-Inflammatory Agents; C491766:Ccl2 protein, rat; C492811:Ccn3 protein, rat; D018932:Chemokine CCL2; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D003907:Dexamethasone; D005620:Freund's Adjuvant; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9