Nitric oxide sustains nuclear factor kappaB activation in cytokine-stimulated chondrocytes

• Published in: Osteoarthritis and cartilage Vol. 12; no. 7; pp. 552 - 558
• Main Authors: Clancy, R.M, Gomez, P.F, Abramson, S.B
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2004
• Subjects: Animals; Cattle; Cells, Cultured; Chondrocytes - drug effects; Chondrocytes - metabolism; Cysteine - analogs & derivatives; Cysteine - pharmacology; Cytokines - metabolism; Cytosol - drug effects; Cytosol - metabolism; Enzyme Inhibitors - pharmacology; Fluorescent Antibody Technique - methods; Free Radical Scavengers - pharmacology; Immunoblotting - methods; NF-kappa B - metabolism; NF-kappaB (NF-κB); Nitric oxide; Nitric Oxide - pharmacology; Nitric Oxide Donors - pharmacology; Nitric Oxide Synthase - analysis; Nitric Oxide Synthase Type II; Nitroso Compounds - pharmacology; omega-N-Methylarginine - pharmacology; Osteoarthritis; Peroxynitrous Acid - pharmacology; Reverse Transcriptase Polymerase Chain Reaction - methods; Osteoarthritis; Nitric oxide; NF-kappaB (NF-κB)
• ISSN: 1063-4584; 1522-9653
• DOI: 10.1016/j.joca.2004.04.003

In the current studies we have examined the effects of nitric oxide, and its redox derivatives peroxynitrite and S-nitrosothiol, S-nitrosocysteine, on nuclear factor kappaB (NF-κB) activation in cytokine-stimulated bovine chondrocytes. The kinetics of NF-κB activation (p65 nuclear translocation) were assessed by immunofluorescence and immunoblot assays. We observed that the two nitric oxide redox species, peroxynitrite and S-nitrosocysteine, exert opposing effects on NF-κB activation. However, in lipopolysaccharide (LPS)/cytokine-stimulated chondrocytes (LPS, IL-1β and TNF-α (LIT)) in the presence or absence of the NOS inhibitor l-NG-monomethyl arginine citrate ( l-NMMA), the results indicate that nitric oxide causes persistent activation of NF-κB, most likely via generation of the free radical derivative peroxynitrite. The studies indicate that while nitric oxide is not required for immediate NF-κB activation in cytokine-stimulated chondrocytes, its effect is to sustain nuclear translocation of p65 and thereby provide a persistent “on signal” to NF-κB dependent gene transcription. Persistent activation of NF-κB may represent a mechanism by which nitric oxide sustains catabolic processes and promotes cartilage degeneration in osteoarthritis.