title: Hydrogen peroxide differentially modulates cardiac myocyte nitric oxide synthesis.
abstract: Nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) are synthesized within cardiac myocytes and play key roles in modulating cardiovascular signaling. Cardiac myocytes contain both the endothelial (eNOS) and neuronal (nNOS) NO synthases, but the differential roles of these NOS isoforms and the interplay of reactive oxygen species and reactive nitrogen species in cardiac signaling pathways are poorly understood. Using a recently developed NO chemical sensor [Cu(2)(FL2E)] to study adult cardiac myocytes from wild-type, eNOS(null), and nNOS(null) mice, we discovered that physiological concentrations of H(2)O(2) activate eNOS but not nNOS. H(2)O(2)-stimulated eNOS activation depends on phosphorylation of both the AMP-activated protein kinase and kinase Akt, and leads to the robust phosphorylation of eNOS. Cardiac myocytes isolated from mice infected with lentivirus expressing the recently developed H(2)O(2) biosensor HyPer2 show marked H(2)O(2) synthesis when stimulated by angiotensin II, but not following β-adrenergic receptor activation. We discovered that the angiotensin-II-promoted increase in cardiac myocyte contractility is dependent on H(2)O(2), whereas β-adrenergic contractile responses occur independently of H(2)O(2) signaling. These studies establish differential roles for H(2)O(2) in control of cardiac contractility and receptor-dependent NOS activation in the heart, and they identify new points for modulation of NO signaling responses by oxidant stress.
authors: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Juliano L
authors: JL
authors: Sartoretto
authors: Hermann
authors: H
authors: Kalwa
authors: Michael D
authors: MD
authors: Pluth
authors: Stephen J
authors: SJ
authors: Lippard
authors: Thomas
authors: T
authors: Michel
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D003300:Copper / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D015151:Immunoblotting; D007545:Isoproterenol / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D000318:Adrenergic beta-Agonists; D005456:Fluorescent Dyes; D011720:Pyrazoles; D011743:Pyrimidines; D014662:Vasoconstrictor Agents; C516138:dorsomorphin; D000804:Angiotensin II; D009569:Nitric Oxide; D003300:Copper; D006861:Hydrogen Peroxide; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; C496321:Nos1 protein, mouse; C496315:Nos3 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases; D007545:Isoproterenol