Abstract
Vascular peroxidase 1 (VPO1) can utilize reactive oxygen species (ROS) generated from NADPH oxidase (NOX) to catalyze peroxidative reactions. This study was performed to identify a novel pathway of NOX/VPO1 in mediating the oxidative injury following myocardial ischemia reperfusion (IR). In a rat model of myocardial IR, the infarct size, serum creatine kinase (CK) activity, apoptosis, NOX activity, NOX2 and VPO1 expression were measured. In a cell (rat heart-derived H9c2 cells) model of hypoxia/reoxygenation (HR), the apoptosis, NOX activity, NOX2 and VPO1 expression, and H(2)O(2) and HOCl levels were examined. In vivo, IR caused 54.8 ± 1.7 % infarct size in myocardium accompanied by elevated activities of CK, caspase-3 and NOX, up-regulated VPO1 expression and high numbers of myocardial apoptotic cells; these effects were attenuated by pretreatment with the inhibitor of NOX. In vitro, inhibition of NOX or silencing of NOX2 or VPO1 expression significantly suppressed HR-induced cellular apoptosis concomitantly with decreased HOCl production. Inhibition of NOX or silencing of NOX2 led to a decrease in H(2)O(2) production accompanied by a decrease in VPO1 expression and HOCl production. However, silencing of VPO1 expression did not affect NOX2 expression and H(2)O(2) production. H(2)O(2)-induced VPO1 expression was partially reversed by JNK or p38 MAPK inhibitor. Our results demonstrate a novel pathway of NOX2/VPO1 in myocardium, where VPO1 coordinates with NOX2 and amplifies the role of NOX-derived ROS in oxidative injury following IR.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis
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Caspase 3 / metabolism
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Cell Line
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Creatine Kinase / blood
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Disease Models, Animal
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Enzyme Inhibitors / pharmacology
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Hemeproteins / genetics
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Hemeproteins / metabolism*
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Hydrogen Peroxide / metabolism
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Hypochlorous Acid / metabolism
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JNK Mitogen-Activated Protein Kinases / antagonists & inhibitors
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JNK Mitogen-Activated Protein Kinases / metabolism
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Male
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Membrane Glycoproteins / antagonists & inhibitors
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism*
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Myocardial Infarction / enzymology*
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Myocardial Infarction / genetics
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Myocardial Infarction / pathology
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Myocardial Reperfusion Injury / enzymology*
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Myocardial Reperfusion Injury / genetics
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Myocardial Reperfusion Injury / pathology
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Myocardium / enzymology*
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Myocardium / pathology
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NADPH Oxidase 2
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NADPH Oxidase 4
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NADPH Oxidases / antagonists & inhibitors
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NADPH Oxidases / genetics
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NADPH Oxidases / metabolism*
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Oxidative Stress* / drug effects
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Peroxidases / genetics
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Peroxidases / metabolism*
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RNA Interference
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Rats
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Rats, Sprague-Dawley
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Signal Transduction* / drug effects
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Transfection
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p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
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p38 Mitogen-Activated Protein Kinases / metabolism
Substances
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Enzyme Inhibitors
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Hemeproteins
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Membrane Glycoproteins
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Hypochlorous Acid
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Hydrogen Peroxide
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vascular peroxidase, rat
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Peroxidases
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Cybb protein, rat
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NADPH Oxidase 2
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NADPH Oxidase 4
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NADPH Oxidases
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Nox4 protein, rat
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JNK Mitogen-Activated Protein Kinases
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p38 Mitogen-Activated Protein Kinases
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Creatine Kinase
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Casp3 protein, rat
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Caspase 3