title: Hepatocyte growth factor induction of collagenase 3 production in human osteoarthritic cartilage: involvement of the stress-activated protein kinase/c-Jun N-terminal kinase pathway and a sensitive p38 mitogen-activated protein kinase inhibitor cascade.
abstract: OBJECTIVE
  Osteoarthritis (OA) involves both a decreased reparative process and an increased degradative phenomenon. Several cytokines and growth factors are known to facilitate the repair of articular cartilage defects. The hepatocyte growth factor (HGF) present in OA cartilage is suggested to be involved in the cartilage repair process as well as in matrix remodeling and chondrocyte migration, leading to partial reconstruction of articular cartilage. Since cell migration is often correlated with metalloprotease activity, the effect of HGF on collagenase 3 production was studied because of its possible implication in OA cartilage remodeling.
  
  
  METHODS
  We examined HGF-stimulated collagenase 3 production in human OA chondrocytes by Western and Northern blotting. Furthermore, we explored the intracellular signaling pathways through which HGF induced collagenase 3 production.
  
  
  RESULTS
  This study showed that HGF stimulated collagenase 3 production in human OA chondrocytes at the transcriptional level, and this induction was mediated by activation of the stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK) pathway, but not the p38 mitogen-activated protein kinase (MAPK). The p44/42 MAPKs were also phosphorylated and the use of their specific inhibitor (PD 98059) did not affect HGF-induced collagenase 3 production in OA chondrocytes. Induced collagenase 3 production via the SAPK/JNK pathway was mediated, at least in part, by the TRE site in the promoter, and in the activator protein 1 complex, c-Jun, JunD, and Fra-1 were activated. Surprisingly, further experiments revealed that the specific p38 MAPK inhibitor SB 202190 also inhibited collagenase 3 production early in the HGF-induced process. The 50% inhibitory concentration was as low as 50 nM, which is unlikely to be related to p38 MAPK inhibition (which is usually in the microM range), suggesting the involvement of another kinase sensitive to SB 202190.
  
  
  CONCLUSIONS
  This is the first study to show that HGF has the ability to induce both the expression and synthesis of collagenase 3 in OA chondrocytes. The effect is mediated by kinase cascades involving SAPK/JNK and another, unidentified kinase. This study provides novel information implicating a role for HGF in the pathophysiology of OA through its effect on the production of collagenase 3, which is an enzyme that is possibly involved in OA cartilage remodeling.
authors.affiliation: Unité de Recherche en Arthrose, H pital Notre-Dame, Centre Hospitalier de l'Université de Montreal, Quebec, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Reboul
authors.forename: J P
authors.initials: JP
authors.lastname: Pelletier
authors.forename: G
authors.initials: G
authors.lastname: Tardif
authors.forename: M
authors.initials: M
authors.lastname: Benderdour
authors.forename: P
authors.initials: P
authors.lastname: Ranger
authors.forename: D P
authors.initials: DP
authors.lastname: Bottaro
authors.forename: J
authors.initials: J
authors.lastname: Martel-Pelletier
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D002352:Carrier Proteins / Q000502:physiology; D002358:Cartilage, Articular / Q000166:cytology / Q000201:enzymology*; D017364:Collagenases / Q000096:biosynthesis*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D053509:Matrix Metalloproteinase 13; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D009419:Nerve Tissue Proteins; D010003:Osteoarthritis / Q000201:enzymology*; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C485750:MAPK8IP3 protein, human; D009419:Nerve Tissue Proteins; D017228:Hepatocyte Growth Factor; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13