title: Adenosine A2receptor activation ameliorates mitochondrial oxidative stress upon reperfusion through the posttranslational modification of NDUFV2 subunit of complex I in the heart.
abstract: While it is well known that adenosine receptor activation protects the heart from ischemia/reperfusion injury, the precise mitochondrial mechanism responsible for the action remains unknown. This study probed the mitochondrial events associated with the cardioprotective effect of 5'-(N-ethylcarboxamido) adenosine (NECA), an adenosine A2receptor agonist. Isolated rat hearts were subjected to 30min ischemia followed by 10min of reperfusion, whereas H9c2 cells experienced 20min ischemia and 10min reperfusion. NECA prevented mitochondrial structural damage, decreases in respiratory control ratio (RCR), and collapse of mitochondrial membrane potential (ΔΨm). Both the adenosine A2Areceptor antagonist SCH58261 and A2Breceptor antagonist MRS1706 inhibited the action of NECA. NECA reduced mitochondrial proteins carbonylation, H2O2, and superoxide generation at reperfusion, but did not change superoxide dismutase (SOD) activity. In support, the protective effects of NECA and Peg-SOD on ΔΨm upon reperfusion were additive, implying that NECA's protection is attributable to the reduced superoxide generation but not to the enhancement of the superoxide-scavenging capacity. NECA increased the mitochondrial Src tyrosine kinase activity and suppressed complex I activity at reperfusion in a Src-dependent manner. NECA also reduced mitochondrial superoxide through Src tyrosine kinase. Studies with liquid chromatography-mass spectrometer (LC-MS) identified Tyr118 of the NDUFV2 subunit of complex 1 as a likely site of the tyrosine phosphorylation. Furthermore, the complex I activity of cells transfected with the Y118F mutant was increased, suggesting that this site might be a negative regulator of complex I activity. In support, NECA failed to suppress complex I activity at reperfusion in cells transfected with the Y118F mutant of NDUFV2. In conclusion, NECA prevents mitochondrial oxidative stress by decreasing mitochondrial superoxide generation through inhibition of complex I via the mitochondrial Src tyrosine kinase. Phosphorylation of Tyr118residue in NDUFV2 subunit may account for the inhibitory effect of NECA on complex I.
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Jingman
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Xiyun
authors.initials: X
authors.lastname: Bian
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Hong
authors.affiliation: Department of Cardiology, General Hospital, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Tianming
authors.initials: T
authors.lastname: Teng
authors.affiliation: Department of Cardiology, General Hospital, Tianjin Medical University, Tianjin 300070, China. Electronic address: zxu@tmu.edu.cn.
authors.forename: Yuemin
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070, China. Electronic address: zxu@tmu.edu.cn.
authors.forename: Zhelong
authors.initials: Z
authors.lastname: Xu
mesh_terms: D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000008:administration & dosage*; D000818:Animals; D042967:Electron Transport Complex I / Q000378:metabolism; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009154:Mutation; D009203:Myocardial Infarction / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009245:NADH Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D011687:Purines / Q000008:administration & dosage; D011743:Pyrimidines / Q000008:administration & dosage; D051381:Rats; D043683:Receptors, Adenosine A2 / Q000187:drug effects / Q000378:metabolism*; D014230:Triazoles / Q000008:administration & dosage
chemical_list: C098657:5-amino-7-(2-phenylethyl)-2-(2-furyl)pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c)pyrimidine; C496145:N-(4-acetylphenyl)-2-(4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)phenoxy)acetamide; D011687:Purines; D011743:Pyrimidines; D043683:Receptors, Adenosine A2; D014230:Triazoles; D019830:Adenosine-5'-(N-ethylcarboxamide); D009245:NADH Dehydrogenase; D042967:Electron Transport Complex I
keywords: Adenosine A(2) receptors; Complex I; NDUFV2; NECA; Src tyrosine kinase; Superoxide