title: Tetracycline up-regulates COX-2 expression and prostaglandin E2 production independent of its effect on nitric oxide.
abstract: Tetracyclines (doxycycline and minocycline) augmented (one- to twofold) the PGE2 production in human osteoarthritis-affected cartilage (in the presence or absence of cytokines and endotoxin) in ex vivo conditions. Similarly, bovine chondrocytes stimulated with LPS showed (one- to fivefold) an increase in PGE2 accumulation in the presence of doxycycline. This effect was observed at drug concentrations that did not affect nitric oxide (NO) production. In murine macrophages (RAW 264.7) stimulated with LPS, tetracyclines inhibited NO release and increased PGE2 production. Tetracycline(s) and L-N-monomethylarginine (L-NMMA) (NO synthase inhibitor) showed an additive effect on inhibition of NO and PGE2 accumulation, thereby uncoupling the effects of tetracyclines on NO and PGE2 production. The enhancement of PGE2 production in RAW 264.7 cells by tetracyclines was accompanied by the accumulation of both cyclooxygenase (COX)-2 mRNA and cytosolic COX-2 protein. In contrast to tetracyclines, L-NMMA at low concentrations (< or = 100 microM) inhibited the spontaneous release of No in osteoarthritis-affected explants and LPS-stimulated macrophages but had no significant effect on the PGE2 production. At higher concentrations, L-NMMA (500 microM) inhibited NO release but augmented PGE2 production. This study indicates a novel mechanism of action of tetracyclines to augment the expression of COX-2 and PGE2 production, an effect that is independent of endogenous concentration of NO.
authors: Department of Rheumatology, Hospital for Joint Diseases, New York 10003, USA.
authors: M G
authors: MG
authors: Attur
authors: R N
authors: RN
authors: Patel
authors: P D
authors: PD
authors: Patel
authors: S B
authors: SB
authors: Abramson
authors: A R
authors: AR
authors: Amin
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D051546:Cyclooxygenase 2; D016207:Cytokines / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis*; D004318:Doxycycline / Q000494:pharmacology; D004731:Endotoxins / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008565:Membrane Proteins; D051379:Mice; D008911:Minocycline / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009924:Organ Culture Techniques; D010003:Osteoarthritis / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D013752:Tetracycline / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D016207:Cytokines; D004731:Endotoxins; D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D013752:Tetracycline; D008911:Minocycline; D015232:Dinoprostone; D004318:Doxycycline