Role of nitric oxide in the activation of NF-kappaB, AP-1 and NOS II expression in articular chondrocytes.
OBJECTIVE
Determine the sources of nitric oxide (NO) and evaluate its role in the activation of nuclear Factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) and in the expression of NO synthase II (NOS II), induced by interleukin-1beta (IL-1).


METHODS
Primary cultures of bovine articular chondrocytes.


METHODS
The cells were treated with IL-1, 5 ng/ml with or without the NO donor S-nitroso-N-acetylpenicillamine (SNAP), in concentrations ranging from 10 to 300 microM.


METHODS
NF-kappaB and AP-1 activation were evaluated by electrophoretic mobility shift assay. Northern blot was used to detect NOS II mRNA levels and western blot to evaluate IkappaB-alpha, NOS I and NOS II protein levels.


RESULTS
Under basal conditions, chondrocytes expressed NOS I, which was lost upon IL-I treatment. SNAP inhibited IL-I-induced NF-kappaB activation and NOS II expression. When added alone, SNAP induced AP-1 activation to approximately the same extent as IL-I.


CONCLUSIONS
These results suggest that, in chondrocytes, NO is a key regulator of the signaling pathways leading from IL-I to NF-kappaB and AP-1 activation and to the expression of genes that are involved in the pathophysiology of arthritic diseases.
Mendes
A F
AF
Faculty of Pharmacy, University of Coimbra, Portugal. alexandrinam@hotmail.com
Carvalho
A P
AP
Caramona
M M
MM
Lopes
M C
MC
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D002467:Cell Nucleus / Q000201:enzymology / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D024202:Electrophoretic Mobility Shift Assay; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology; D016328:NF-kappa B / Q000096:biosynthesis*; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D018808:Transcription Factor AP-1 / Q000096:biosynthesis*
D007375:Interleukin-1; D016328:NF-kappa B; D020030:Nitric Oxide Donors; D018808:Transcription Factor AP-1; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II