title: TNF-alpha protects human primary articular chondrocytes from nitric oxide-induced apoptosis via nuclear factor-kappaB.
abstract: TNF-alpha plays a key role in rheumatoid arthritis, but its effect on chondrocyte survival is still conflicting. In the present study, we tested how TNF-alpha influences chondrocyte survival in response to nitric oxide (NO)-related apoptotic signals, which are abundant during rheumatoid arthritis. Human primary articular chondrocytes or cartilage explants were pretreated with TNF-alpha for 24 hours and then treated with the proapoptotic NO donor sodium-nitro-prusside (SNP) for an additional 24 hours. TNF-alpha pretreatment markedly protected chondrocytes from SNP-induced cell death. Preincubation of chondrocytes with TNF-alpha inhibited both SNP-induced high-molecular weight DNA fragmentation and annexin V-FITC binding. Of interest, TNF-alpha induced persistent nuclear factor-kappaB (NF-kappaB)-DNA binding activity even in the presence of SNP, mirroring apoptosis protection effects. Both the TNF-alpha antiapoptotic effect and NF-kappaB-DNA binding activity were significantly inhibited by NF-kappaB inhibitors, Bay 11-7085, MG-132, and adenovirus-expressing mutated IkappaB-alpha. Phosphatidylinositol-3 kinase inhibitor LY 294002 also markedly inhibited the antiapoptotic effect of TNF-alpha. In primary chondrocytes, TNF-alpha induced expression of the antiapoptotic protein Cox-2, which persisted in the presence of SNP, and a specific Cox-2 inhibitor significantly blocked the TNF-alpha protective effect. We therefore conclude that TNF-alpha-mediated protection of chondrocytes from NO-induced apoptosis acts through NF-kappaB and requires Cox-2 activity.
authors.affiliation: Center for Cellular and Molecular Therapy, University of Liège, Belgium.
authors.forename: Biserka
authors.initials: B
authors.lastname: Relić
authors.forename: Mohamed
authors.initials: M
authors.lastname: Bentires-Alj
authors.forename: Clio
authors.initials: C
authors.lastname: Ribbens
authors.forename: Nathalie
authors.initials: N
authors.lastname: Franchimont
authors.forename: Pierre-André
authors.initials: PA
authors.lastname: Guerne
authors.forename: Valerie
authors.initials: V
authors.lastname: Benoît
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Merville
authors.forename: Vincent
authors.initials: V
authors.lastname: Bours
authors.forename: Michel G
authors.initials: MG
authors.lastname: Malaise
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics; D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002358:Cartilage, Articular; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000473:pathology; D002867:Chromones / Q000494:pharmacology; D051546:Cyclooxygenase 2; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D005822:Genetic Vectors; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D007976:Leupeptins / Q000494:pharmacology; D008565:Membrane Proteins; D008875:Middle Aged; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009570:Nitriles; D009599:Nitroprusside / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis; D013450:Sulfones; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; C416282:BAY 11-7085; D002867:Chromones; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D007976:Leupeptins; D008565:Membrane Proteins; D009025:Morpholines; D016328:NF-kappa B; D020030:Nitric Oxide Donors; D009570:Nitriles; D013450:Sulfones; D014409:Tumor Necrosis Factor-alpha; D009599:Nitroprusside; D009569:Nitric Oxide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde