title: Direct inhibition of type 5 adenylyl cyclase prevents myocardial apoptosis without functional deterioration.
abstract: Adenylyl cyclase, a major target enzyme of beta-adrenergic receptor signals, is potently and directly inhibited by P-site inhibitors, classic inhibitors of this enzyme, when the enzyme catalytic activity is high. Unlike beta-adrenergic receptor antagonists, this is a non- or uncompetitive inhibition with respect to ATP. We have examined whether we can utilize this enzymatic property to regulate the effects of beta-adrenergic receptor stimulation differentially. After screening multiple new and classic compounds, we found that some compounds, including 1R,4R-3-(6-aminopurin-9-yl)-cyclopentanecarboxylic acid hydroxyamide, potently inhibited type 5 adenylyl cyclase, the major cardiac isoform, but not other isoforms. In normal mouse cardiac myocytes, contraction induced by low beta-adrenergic receptor stimulation was poorly inhibited with this compound, but the induction of cardiac myocyte apoptosis by high beta-adrenergic receptor stimulation was effectively prevented by type 5 adenylyl cyclase inhibitors. In contrast, when cardiac myocytes from type 5 adenylyl cyclase knock-out mice were examined, beta-adrenergic stimulation poorly induced apoptosis. Our data suggest that the inhibition of beta-adrenergic signaling at the level of the type 5 adenylyl cyclase isoform by P-site inhibitors may serve as an effective method to prevent cardiac myocyte apoptosis induced by excessive beta-adrenergic stimulation without deleterious effect on cardiac myocyte contraction.
authors.affiliation: Department of Physiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan.
authors.forename: Kousaku
authors.initials: K
authors.lastname: Iwatsubo
authors.forename: Susumu
authors.initials: S
authors.lastname: Minamisawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsunematsu
authors.forename: Masamichi
authors.initials: M
authors.lastname: Nakagome
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Toya
authors.forename: James E
authors.initials: JE
authors.lastname: Tomlinson
authors.forename: Satoshi
authors.initials: S
authors.lastname: Umemura
authors.forename: Robert M
authors.initials: RM
authors.lastname: Scarborough
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Levy
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ishikawa
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D020287:In Situ Nick-End Labeling; D007313:Insecta; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008956:Models, Chemical; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000378:metabolism; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D000099211:Phospholamban
chemical_list: D000255:Adenosine Triphosphate; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases; D002135:Calcium-Binding Proteins; D053148:Caspase 3; D020169:Caspases; D000242:Cyclic AMP; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D020033:Protein Isoforms; D000099211:Phospholamban; C505409:Casp3 protein, mouse; C419510:adenylyl cyclase type V