title: The induction of cell death in human osteoarthritis chondrocytes by nitric oxide is related to the production of prostaglandin E2 via the induction of cyclooxygenase-2.
abstract: There is increasing evidence suggesting that chondrocyte death may contribute to the progression of osteoarthritis (OA). This study focused on the characterization of signaling cascade during NO-induced cell death in human OA chondrocytes. The NO generator, sodium nitroprusside (SNP), promoted chondrocyte death in association with DNA fragmentation, caspase-3 activation, and down-regulation of Bcl-2. Both caspase-3 inhibitor Z-Asp(OCH3)-Glu(OCH3)-Val-Asp(OCH3)-CH2F and caspase-9 inhibitor Z-Leu-Glu(OCH3)-His-Asp(OCH3)-CH2F prevented the chondrocyte death. Blocking the mitogen-activated protein kinase pathway by the mitogen-activated protein kinase kinase 1/2 inhibitor PD98059 or p38 kinase inhibitor SB202190 also inhibited the SNP-mediated cell death, suggesting possible requirements of both extracellular signal-related protein kinase 1/2 and p38 kinase for the NO-induced cell death. Furthermore, the selective inhibition of cyclooxygenase (COX)-2 by NS-398 or the inhibition of COX-1/COX-2 by indomethacin blocked the SNP-induced cell death. The chondrocyte death induced by SNP was associated with an overexpression of COX-2 protein (as determined by Western blotting) and an increase in PGE2 release. PD98059 and SB202190, but neither Z-DEVD FMK nor Z-LEHD FMK completely inhibited the SNP-mediated PGE2 production. Analysis of interactions between PGE2 and the cell death showed that PGE2 enhanced the SNP-mediated cell death, whereas PGE2 alone did not induce the chondrocyte death. These data indicate that NO-induced chondrocyte death signaling includes PGE2 production via COX-2 induction and suggest that both extracellular signal-related protein kinase 1/2 and p38 kinase pathways are upstream signaling of the PGE2 production. The results also demonstrate that exogenous PGE2 may sensitize human OA chondrocytes to the cell death induced by NO.
authors.affiliation: Unité de Recherche en Arthrose, Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montréal, Québec, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Notoya
authors.forename: D V
authors.initials: DV
authors.lastname: Jovanovic
authors.forename: P
authors.initials: P
authors.lastname: Reboul
authors.forename: J
authors.initials: J
authors.lastname: Martel-Pelletier
authors.forename: F
authors.initials: F
authors.lastname: Mineau
authors.forename: J P
authors.initials: JP
authors.lastname: Pelletier
mesh_terms: D000368:Aged; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis* / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D009569:Nitric Oxide / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D010003:Osteoarthritis / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors
chemical_list: D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D009599:Nitroprusside; D009569:Nitric Oxide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D015232:Dinoprostone