title: Cyclic AMP mediates endothelial protection by nitric oxide.
abstract: Incubation with TNF-alpha (50 ng/ml) for 72 hours markedly reduced viability of endothelial cells. A 6-hour preincubation with S-nitroso-N-acetyl-D,L-penicillamine (SNAP, 3-100 microM) protected cells in a concentration-dependent manner and decreased TNF-alpha-mediated toxicity by up to 70%. Cytoprotection by SNAP was completely abolished by the adenylyl cyclase inhibitor 2', 5'-dideoxyadenosine and mimicked by 8-bromo cyclic AMP or forskolin. SNAP produced significant increases in cyclic GMP and cyclic AMP, both being abrogated in the presence of the NO scavenger 2-phenyl-4, 4,5,5,-tetramethylimidazoline-1-oxyl-3-oxide (PTIO). Moreover, no endothelial protection by SNAP was detected in the presence of the protein kinase A inhibitor KT5720, whereas the protein kinase G inhibitor KT5823 left cytoprotection virtually unaltered. Our results demonstrate a crucial role for cyclic AMP in mediating NO-induced endothelial protection against TNF-alpha, possibly through cyclic GMP-dependent inhibition of cyclic AMP breakdown. NO-dependent endothelial protection may ultimately result from cyclic AMP-induced up-regulation of antioxidant proteins or down-regulation of cytotoxic processes.
authors.affiliation: School of Pharmacy, Martin Luther University, Wolfgang-Langenbeck-Strasse 4, Halle (Saale), 06099, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Polte
authors.forename: H
authors.initials: H
authors.lastname: Schröder
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000067956:Adenylyl Cyclase Inhibitors; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002227:Carbazoles; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D006152:Cyclic GMP / Q000378:metabolism; D003497:Cyclic N-Oxides / Q000494:pharmacology; D016048:Dideoxyadenosine / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D009569:Nitric Oxide / Q000494:pharmacology / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011651:Pulmonary Artery; D011758:Pyrroles / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D026423:S-Nitroso-N-Acetylpenicillamine; D014409:Tumor Necrosis Factor-alpha / Q000633:toxicity
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D000067956:Adenylyl Cyclase Inhibitors; D000470:Alkaloids; D002227:Carbazoles; D003497:Cyclic N-Oxides; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007093:Imidazoles; D007211:Indoles; D020030:Nitric Oxide Donors; D010069:Oxadiazoles; D011758:Pyrroles; D011810:Quinoxalines; D014409:Tumor Necrosis Factor-alpha; C073601:KT 5823; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D009569:Nitric Oxide; D016048:Dideoxyadenosine; C057416:KT 5720; D026423:S-Nitroso-N-Acetylpenicillamine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D010396:Penicillamine; D006152:Cyclic GMP