title: Mitochondrial Src tyrosine kinase plays a role in the cardioprotective effect of ischemic preconditioning by modulating complex I activity and mitochondrial ROS generation.
abstract: While ischemic preconditioning (IPC) and other cardioprotective interventions have been proposed to protect the heart from ischemia/reperfusion (I/R) injury by inhibiting mitochondrial complex I activity upon reperfusion, the exact mechanism underlying the modulation of complex I activity remains elusive. This study was aimed to test the hypothesis that IPC modulates complex I activity at reperfusion by activating mitochondrial Src tyrosine kinase, and induces cardioprotection against I/R injury. Isolated rat hearts were preconditioned by three cycles of 5-min ischemia and 5-min reperfusion prior to 30-min index ischemia followed by 2 h of reperfusion. Mitochondrial Src phosphorylation (Tyr(416)) was dramatically decreased during I/R, implying inactivation of Src tyrosine kinase by I/R. IPC increased mitochondrial Src phosphorylation upon reperfusion and this was inhibited by the selective Src tyrosine kinase inhibitor PP2. IPC's anti-infarct effect was inhibited by the selective Src tyrosine kinase inhibitor PP2. Complex I activity was significantly increased upon reperfusion, an effect that was prevented by IPC in a Src tyrosine kinase-dependent manner. In support, Src and phospho-Src were found in complex I. Furthermore, IPC prevented hypoxia/reoxygenation-induced mitochondrial reactive oxygen species (ROS) generation and cellular injury in rat cardiomyocytes, which was revoked by PP2. Finally, IPC reduced LDH release induced by both hypoxia/reoxygenation and simulated ischemia/reperfusion, an effect that was reversed by PP2 and Src siRNA. These data suggest that mitochondrial Src tyrosine kinase accounts for the inhibitory action of IPC on complex I and mitochondrial ROS generation, and thereby plays a role in the cardioprotective effect of IPC.
authors.affiliation: a Department of Physiology and Pathophysiology , Tianjin Medical University , Tianjin , China.
authors.forename: H
authors.initials: H
authors.lastname: Ge
authors.forename: M
authors.initials: M
authors.lastname: Zhao
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: Z
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000818:Animals; D002460:Cell Line; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors* / Q000502:physiology; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008929:Mitochondria, Heart / Q000201:enzymology*; D032386:Myoblasts, Cardiac / Q000378:metabolism; D009203:Myocardial Infarction / Q000473:pathology; D017202:Myocardial Ischemia / Q000201:enzymology*; D032383:Myocytes, Cardiac / Q000201:enzymology; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015427:Reperfusion Injury / Q000201:enzymology / Q000517:prevention & control*; D013481:Superoxides / Q000378:metabolism; D019061:src-Family Kinases / Q000502:physiology*
chemical_list: D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D013481:Superoxides; D019061:src-Family Kinases; D054648:Protein Phosphatase 2; D042967:Electron Transport Complex I
keywords: cardioprotection; ischemia reperfusion; mitochondria; protein kinases; reactive oxygen species