title: Dual regulation of metalloproteinase expression in chondrocytes by Wnt-1-inducible signaling pathway protein 3/CCN6.
abstract: OBJECTIVE
  Wnt-1-inducible signaling pathway protein 3 (WISP-3)/CCN6 is mutated in progressive pseudorheumatoid dysplasia and may have effects on cartilage homeostasis. The aim of this study was to ascertain additional roles for WISP-3/CCN6 by determining its expression in osteoarthritic (OA) cartilage and by investigating its effects on cartilage-relevant metalloproteinase expression in immortalized (C-28/I2) and primary chondrocytes.
  
  
  METHODS
  Cartilage steady-state levels of WISP-3/CCN6 messenger RNA and protein production were determined by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. WISP-3/CCN6 was overexpressed in C-28/I2 cells, and the resultant clones were analyzed by quantitative RT-PCR. The stable clones were analyzed by RT-PCR for metalloproteinase expression, and the signaling pathways involved were investigated using pharmacologic inhibition. The effects of WISP-3/CCN6 on metalloproteinase expression in primary chondrocytes were investigated using a small interfering RNA approach.
  
  
  RESULTS
  WISP-3/CCN6 was highly expressed in OA cartilage compared with undamaged cartilage, at both the RNA and protein levels. WISP-3/CCN6 overexpression in C-28/I2 cells resulted in unexpected dual regulation of metalloproteinases; expression of the potent aggrecanase ADAMTS-5 was down-regulated 9-fold, while expression of MMP-10 was up-regulated 14-fold, and these responses were accentuated in the WISP-3/CCN6 clones grown in suspension. MMP-10 up-regulation was dependent on several MAPKs, but WISP-3/CCN6-mediated ADAMTS-5 repression was independent of these pathways and was partially relieved by activation of β-catenin signaling. WISP-3/CCN6 also suppressed ADAMTS-5 expression in C-28/I2 cells treated with cytokines. In cytokine-treated primary chondrocytes, gene silencing of WISP-3/CCN6 resulted in enhanced ADAMTS-5 expression, while MMP-10 expression was suppressed.
  
  
  CONCLUSIONS
  WISP-3/CCN6 was highly expressed in end-stage OA cartilage, suggesting a role for this growth factor in cartilage homeostasis. WISP-3/CCN6-induced repression of ADAMTS-5 expression and regulation of MMP-10 expression suggest complex and context-dependent roles for WISP-3/CCN6 in cartilage biology.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich, UK.
authors.forename: Natasha
authors.initials: N
authors.lastname: Baker
authors.forename: Paul
authors.initials: P
authors.lastname: Sharpe
authors.forename: Kirsty
authors.initials: K
authors.lastname: Culley
authors.forename: Miguel
authors.initials: M
authors.lastname: Otero
authors.forename: Damon
authors.initials: D
authors.lastname: Bevan
authors.forename: Peter
authors.initials: P
authors.lastname: Newham
authors.forename: Wendy
authors.initials: W
authors.lastname: Barker
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Clements
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Langham
authors.forename: Mary B
authors.initials: MB
authors.lastname: Goldring
authors.forename: Jelena
authors.initials: J
authors.lastname: Gavrilović
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D055511:CCN Intercellular Signaling Proteins / Q000235:genetics / Q000378:metabolism*; D002358:Cartilage, Articular / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D055511:CCN Intercellular Signaling Proteins; C400081:CCN6 protein, human; D045726:Metalloproteases; D051722:ADAM Proteins