title: Nitric oxide preserves XIAP and reduces hypoxia/reoxygenation-induced cardiomyocytes apoptosis via ERK1/2 activation.
abstract: The signaling pathways that control the hypoxia/reoxygenation (H/R)-induced cardiomyocyte apoptosis have not been fully defined. In this study, we investigated whether extracellular signal-regulated kinase1/2 (ERK1/2) plays a role in NO's anti-apoptotic effect against H/R injury. Primary cultures of adult rat ventricular myocytes (ARVMs) were exposed to 3 h of hypoxia followed by 30, 60, 90 and 120 min of reoxygenation in presence of a vehicle, NO donor (GSNO, 50 μmol/L) and inhibitors of ERK1/2 (PD98059, 10 μmol/L). GSNO protected the cardiomyocyte from reoxygenation injury, as evidenced by decreased apoptosis, and this protective effect was inhibited by co-treatment with PD98059 during reoxygenation. Consistent with this, when administered with adenoviral vector encoding dominant negative ERK (Ad-dnERK), GSNO's effect was also blocked. Western blotting revealed that GSNO increased the ERK phosphorylation during reoxygenation. Furthermore, H/R-induced activation of caspase-3 and -9 were attenuated by GSNO. Interestingly, X-linked inhibitor of apoptosis protein (XIAP) protein levels decreased in myocytes subjected to reoxygenation, and ERK phosphorylation can improve XIAP expression, which involved inhibiting caspase-3, -7 and -9 activities. Overexpression experiment with adenoviral vector containing constitutively active ERK (Ad-caERK) alone acquired protection against apoptosis triggered by H/R injury and positively regulated XIAP expression compared with control adenovirus (Ad-LacZ). Our data demonstrated that, GSNO's antiapoptotic effect against reoxygenation injury involves ERK signaling pathway. The activation of ERK increased XIAP expression and led to decreased caspase activation.
authors.affiliation: Department of Internal Medicine, The First Hospital of Jilin University, Changchun, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Yuan
authors.forename: Bo
authors.initials: B
authors.lastname: Yan
authors.forename: Hejia H
authors.initials: HH
authors.lastname: Wang
authors.forename: Shucheng
authors.initials: S
authors.lastname: Hua
authors.forename: Aihua
authors.initials: A
authors.lastname: Hu
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D015687:Cell Hypoxia; D004789:Enzyme Activation; D005419:Flavonoids / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism*
chemical_list: D005419:Flavonoids; D020030:Nitric Oxide Donors; D047428:Protein Kinase Inhibitors; D051636:X-Linked Inhibitor of Apoptosis Protein; D009569:Nitric Oxide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D053148:Caspase 3; D053453:Caspase 9; D010100:Oxygen; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one