Abstract
Increased levels of inflammatory cytokines contribute to the pathophysiology of pulmonary hypertension. Prostacyclin (PGI2) analogues, which relax pulmonary vessels mainly through cAMP elevation, have a major therapeutic role. In this study, we show that prolonged incubation with bradykinin (BK), interleukin-1beta (IL-1beta), and transforming growth factor-beta1 (TGF-beta1) markedly impairs cAMP accumulation in human pulmonary artery smooth muscle cells in response to short-term incubation with prostaglandin E2 (PGE2) and the PGI2 analogues iloprost and carbaprostacyclin. A similar reduction in cAMP accumulation in response to a direct adenylyl cyclase activator, forskolin, suggested that the effect was attributable to downregulation of adenylyl cyclase. Reverse transcriptase-polymerase chain reaction studies showed downregulation of adenylyl cyclase isoforms 1, 2, and 4. The effect of IL-1beta, BK, and TGF-beta1 on cAMP levels was abrogated by the selective COX-2 inhibitor NS398. Furthermore, it was mimicked by prolonged incubation with the COX-2 product PGE2 and PGI2 analogues or the COX substrate arachidonic acid, suggesting that it was mediated by endogenous prostanoids produced by COX-2. Consistent with this, IL-1beta, BK, and TGF-beta1 all induced COX-2 and PGE2 release. These results show that BK, IL-1beta, and TGF-beta1 downregulate adenylyl cyclase in human pulmonary artery smooth muscle cells via COX-2 induction and prostanoid release. This suggests a novel mechanism whereby mediators and cytokines produced in pulmonary hypertension may impair the therapeutic effects of prostacyclin analogues such as iloprost and carbaprostacyclin.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenylyl Cyclases / genetics*
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Adenylyl Cyclases / metabolism
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Adult
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Arachidonic Acid / pharmacology
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Bradykinin / pharmacology
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Cells, Cultured
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Colforsin / pharmacology
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Cyclic AMP / metabolism*
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Cyclooxygenase 2
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Dinoprostone / pharmacology
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Dose-Response Relationship, Drug
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Down-Regulation / drug effects
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Enzyme Induction / drug effects
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Epoprostenol / analogs & derivatives
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Epoprostenol / pharmacology
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Gene Expression Regulation, Enzymologic / drug effects
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Growth Substances / pharmacology*
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Humans
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Interleukin-1 / pharmacology
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Isoenzymes / biosynthesis*
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Isoproterenol / pharmacology
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Membrane Proteins
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Muscle, Smooth, Vascular / cytology
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Muscle, Smooth, Vascular / drug effects*
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Muscle, Smooth, Vascular / metabolism
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Nitrobenzenes / pharmacology
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Prostaglandin-Endoperoxide Synthases / biosynthesis*
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Prostaglandins / pharmacology*
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Pulmonary Artery / cytology
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Pulmonary Artery / drug effects
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Pulmonary Artery / metabolism
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RNA, Messenger / drug effects
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Sulfonamides / pharmacology
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Transforming Growth Factor beta / pharmacology
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Transforming Growth Factor beta1
Substances
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Growth Substances
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Interleukin-1
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Isoenzymes
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Membrane Proteins
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Nitrobenzenes
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Prostaglandins
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RNA, Messenger
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Sulfonamides
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TGFB1 protein, human
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Transforming Growth Factor beta
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Transforming Growth Factor beta1
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N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide
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Colforsin
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Arachidonic Acid
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Epoprostenol
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Cyclic AMP
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Cyclooxygenase 2
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PTGS2 protein, human
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Prostaglandin-Endoperoxide Synthases
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Adenylyl Cyclases
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adenylyl cyclase 1
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adenylyl cyclase 2
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adenylyl cyclase 4
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Dinoprostone
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Isoproterenol
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Bradykinin