Relative contribution of matrix metalloprotease and cysteine protease activities to cytokine-stimulated articular cartilage degradation

B C Sondergaard, K Henriksen, H Wulf, S Østergaard, U Schurigt, R Bräuer, I Danielsen, C Christiansen, P Qvist, M A Karsdal

Research output: Contribution to journalJournal articleResearchpeer-review


OBJECTIVE: Both matrix metalloprotease (MMP) activity and cathepsin K (CK) activity have been implicated in cartilage turnover. We investigated the relative contribution of MMP activity and CK activity in cartilage degradation using ex vivo and in vivo models. METHODS: Bovine articular cartilage explants were stimulated with oncostatin M (OSM) 10 ng/ml and tumor necrosis factor-alpha (TNF-alpha) 20 ng/ml in the presence or absence of the broad-spectrum MMP inhibitor GM6001 and the cysteine protease inhibitor, E64. Cartilage degradation was evaluated in the conditioned medium by glycosaminoglycans (GAG), hydroxyproline, and cross-linked C-telopeptide fragments of type II collagen (CTX-II), which were compared to immunohistochemical evaluations of proteoglycans and CTX-II. We assessed MMP expression by gelatine zymography and CK expression by immunohistochemistry. In vivo, CTX-II release was measured from CK-deficient mice. RESULTS: OSM and TNF-alpha combined induced significant (P<0.01) increase in cartilage degradation products measured by hydroxyproline and CTX-II compared to vehicle control. The cytokines potently induced MMP expression, assessed by zymography, and CK expression investigated by immunohistochemistry. Inhibition of MMP activity completely abrogated hydroxyproline and CTX-II release (P<0.01) and GAG release (P<0.05). In contrast, E64 resulted in increased CTX-II release by 100% (P<0.05) and inhibited GAG release by 30%. Up-regulation of CTX-II fragments was confirmed in vivo in CK null mice. CONCLUSION: Inhibition of MMP activity reduced both proteoglycan loss and type II collagen degradation. In contrast, inhibition of cysteine proteases resulted in an increase rather than a decrease in MMP derived fragments of collagen type II degradation, CTX-II, suggesting altered collagen metabolism.
Original languageEnglish
JournalOsteoarthritis and Cartilage
Issue number8
Pages (from-to)738-48
Number of pages10
Publication statusPublished - 1. Aug 2006
Externally publishedYes


  • Animals
  • Arthritis, Experimental
  • Biological Markers
  • Cartilage, Articular
  • Cathepsin K
  • Cathepsins
  • Cattle
  • Collagen Type I
  • Cysteine Endopeptidases
  • Cysteine Proteinase Inhibitors
  • Cytokines
  • Dipeptides
  • Extracellular Matrix
  • Glycosaminoglycans
  • Hydroxyproline
  • Immunohistochemistry
  • Leucine
  • Matrix Metalloproteinases
  • Mice
  • Mice, Knockout
  • Oncostatin M
  • Osteoarthritis, Knee
  • Peptides
  • Stimulation, Chemical
  • Tissue Culture Techniques
  • Tumor Necrosis Factor-alpha


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