NAD(P)H oxidase activity of Nox4 in chondrocytes is both inducible and involved in collagenase expression

Antioxid Redox Signal. 2006 Sep-Oct;8(9-10):1485-96. doi: 10.1089/ars.2006.8.1485.


Reactive oxygen species (ROS) are regulators of redox-sensitive cell signaling pathways. In osteoarthritis, human interleukin-1beta is implicated in cartilage destruction through an ROS-dependent matrix metalloproteinase production. To determine the molecular source of ROS production in the human IL-1beta (hIL-1beta)-sensitive chondrocyte immortalized cell line C-20/A4, transfected cells were constructed that overexpress NAD(P)H oxidases. First, RT-PCR analysis showed that the C-20/A4 cell line expressed Nox2, Nox4, p22( phox ), and p67( phox ), but not p47( phox ). It was found that ROS production by C-20/A4 chondrocytes does not depend on PMA and ionomycin activation. This indicates that Nox2 was not involved in the production of ROS. In C- 20/A4 cells that overexpress Nox4, hIL-1beta stimulated ROS production three times more than the normal production of C-20/A4 cells. Moreover, there was a fourfold increase in the production of collagenase (MMP-1) by chondrocytes that overexpress Nox4. Interestingly, MMP-1 production in cells that overexpress Nox2 was not sensitive to hIL-1beta. These data suggest that under hIL-1beta stimulation, C-20/A4 chondrocytes produce MMP-1 through a Nox4-mediated, ROS-dependent pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / pharmacology
  • Cell Line, Transformed
  • Chondrocytes / drug effects
  • Chondrocytes / metabolism*
  • Collagenases / metabolism*
  • Free Radical Scavengers / pharmacology
  • Gene Expression Regulation / drug effects
  • Humans
  • Hydrogen Peroxide / metabolism
  • Interleukin-1beta / pharmacology
  • Matrix Metalloproteinase 1 / metabolism
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Mutation / genetics
  • NADPH Oxidase 2
  • NADPH Oxidase 4
  • NADPH Oxidases / genetics*
  • NADPH Oxidases / metabolism
  • Phosphoproteins / genetics
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Reactive Oxygen Species / metabolism
  • Superoxides / metabolism
  • Transfection


  • Free Radical Scavengers
  • Interleukin-1beta
  • Membrane Glycoproteins
  • Phosphoproteins
  • Protein Isoforms
  • Reactive Oxygen Species
  • neutrophil cytosol factor 67K
  • Superoxides
  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
  • Hydrogen Peroxide
  • CYBB protein, human
  • NADPH Oxidase 2
  • NADPH Oxidase 4
  • NADPH Oxidases
  • NOX4 protein, human
  • CYBA protein, human
  • Collagenases
  • Matrix Metalloproteinase 1