Matrix metalloproteinase 13 loss associated with impaired extracellular matrix remodeling disrupts chondrocyte differentiation by concerted effects on multiple regulatory factors

Arthritis Rheum. 2010 Aug;62(8):2370-81. doi: 10.1002/art.27512.


Objective: To link matrix metalloproteinase 13 (MMP-13) activity and extracellular matrix (ECM) remodeling to alterations in regulatory factors leading to a disruption in chondrocyte homeostasis.

Methods: MMP-13 expression was ablated in primary human chondrocytes by stable retrotransduction of short hairpin RNA. The effects of MMP-13 knockdown on key regulators of chondrocyte differentiation (SOX9, runt-related transcription factor 2 [RUNX-2], and beta-catenin) and angiogenesis (vascular endothelial growth factor [VEGF]) were scored at the protein level (by immunohistochemical or Western blot analysis) and RNA level (by real-time polymerase chain reaction) in high-density monolayer and micromass cultures under mineralizing conditions. Effects on cellular viability in conjunction with chondrocyte progression toward a hypertrophic-like state were assessed in micromass cultures. Alterations in SOX9 subcellular distribution were assessed using confocal microscopy in micromass cultures and also in osteoarthritic cartilage.

Results: Differentiation of control chondrocyte micromasses progressed up to a terminal phase, with calcium deposition in conjunction with reduced cell viability and scant ECM. MMP-13 knockdown impaired ECM remodeling and suppressed differentiation in conjunction with reduced levels of RUNX-2, beta-catenin, and VEGF. MMP-13 levels in vitro and ECM remodeling in vitro and in vivo were linked to changes in SOX9 subcellular localization. SOX9 was largely excluded from the nuclei of chondrocytes with MMP-13-remodeled or -degraded ECM, and exhibited an intranuclear staining pattern in chondrocytes with impaired MMP-13 activity in vitro or with more intact ECM in vivo.

Conclusion: MMP-13 loss leads to a breakdown in primary human articular chondrocyte differentiation by altering the expression of multiple regulatory factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cartilage, Articular / cytology
  • Cartilage, Articular / metabolism*
  • Cell Differentiation / physiology*
  • Cells, Cultured
  • Chondrocytes / cytology
  • Chondrocytes / metabolism*
  • Chondrogenesis / physiology
  • Collagen Type II / metabolism
  • Core Binding Factor Alpha 1 Subunit / genetics
  • Core Binding Factor Alpha 1 Subunit / metabolism
  • Extracellular Matrix / genetics
  • Extracellular Matrix / metabolism*
  • Humans
  • Immunohistochemistry
  • Matrix Metalloproteinase 13 / genetics
  • Matrix Metalloproteinase 13 / metabolism*
  • Microscopy, Confocal
  • Microscopy, Electron, Transmission
  • Reverse Transcriptase Polymerase Chain Reaction
  • SOX9 Transcription Factor / genetics
  • SOX9 Transcription Factor / metabolism
  • Statistics, Nonparametric
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism
  • beta Catenin / genetics
  • beta Catenin / metabolism


  • Collagen Type II
  • Core Binding Factor Alpha 1 Subunit
  • RUNX2 protein, human
  • SOX9 Transcription Factor
  • SOX9 protein, human
  • Vascular Endothelial Growth Factor A
  • beta Catenin
  • Matrix Metalloproteinase 13