OBJECTIVES: The purpose of this study was to investigate potential roles of rapamycin, a macrocytic lactone produced by Streptomyces hygroscopicus, in myocardial ischemia/reperfusion (I/R) injury. METHODS: Male Wistar rats were pretreated with three different doses of rapamycin (0.25, 2, and 5 mg/kg). Then, isolated rat hearts were exposed to 40 min of global ischemia followed by 120 min of reperfusion using a Langendorff apparatus. Western blot analysis was used to examine changes in the expression levels of ERK1/2 and Akt kinases and LC3 -II/I (a marker of autophagy). The area of myocardial infarction and cardiac function were evaluated. RESULTS: Our results demonstrated that rapamycin mediates cardioprotection in a dose-dependent manner in isolated rat hearts during myocardial I/R injury. Significant a autophagy was induced by rapamycin during I/R. Both, the mitochondrial K(ATP)-channel blocker 5-hydroxydecanoate (5-HD) and the PI3K inhibitor LY294002 (LY) abolished the protection afforded by rapamycin completely, while the inhibitors alone did not influence the infarct size in control hearts. However, the ERK1/2 inhibitor PD98059(PD) and the blocker of autophagy 3-methyladenine (3-MA) had no effect on rapamycin-mediated cardioprtection. CONCLUSIONS: Cardioprotection afforded by rapamycin involves the PI3K pathway and the activation of mitochondrial K(ATP)-channels, but is independent of rapamycin-induced autophagy. This study may have significant impact on clinical practice.
OBJECTIVES: The purpose of this study was to investigate potential roles of rapamycin, a macrocytic lactone produced by Streptomyces hygroscopicus, in myocardial ischemia/reperfusion (I/R) injury. METHODS: Male Wistar rats were pretreated with three different doses of rapamycin (0.25, 2, and 5 mg/kg). Then, isolated rat hearts were exposed to 40 min of global ischemia followed by 120 min of reperfusion using a Langendorff apparatus. Western blot analysis was used to examine changes in the expression levels of ERK1/2 and Akt kinases and LC3 -II/I (a marker of autophagy). The area of myocardial infarction and cardiac function were evaluated. RESULTS: Our results demonstrated that rapamycin mediates cardioprotection in a dose-dependent manner in isolated rat hearts during myocardial I/R injury. Significant a autophagy was induced by rapamycin during I/R. Both, the mitochondrial K(ATP)-channel blocker 5-hydroxydecanoate (5-HD) and the PI3K inhibitor LY294002 (LY) abolished the protection afforded by rapamycin completely, while the inhibitors alone did not influence the infarct size in control hearts. However, the ERK1/2 inhibitor PD98059(PD) and the blocker of autophagy 3-methyladenine (3-MA) had no effect on rapamycin-mediated cardioprtection. CONCLUSIONS: Cardioprotection afforded by rapamycin involves the PI3K pathway and the activation of mitochondrial K(ATP)-channels, but is independent of rapamycin-induced autophagy. This study may have significant impact on clinical practice.
Authors: Michalis Papadakis; Gina Hadley; Maria Xilouri; Lisa C Hoyte; Simon Nagel; M Mary McMenamin; Grigorios Tsaknakis; Suzanne M Watt; Cynthia Wright Drakesmith; Ruoli Chen; Matthew J A Wood; Zonghang Zhao; Benedikt Kessler; Kostas Vekrellis; Alastair M Buchan Journal: Nat Med Date: 2013-02-24 Impact factor: 53.440
Authors: Arun Samidurai; Ramzi Ockaili; Chad Cain; Sean K Roh; Scott M Filippone; Donatas Kraskauskas; Rakesh C Kukreja; Anindita Das Journal: iScience Date: 2020-11-26
Authors: Andrey Krylatov; Leonid Maslov; Sergey Y Tsibulnikov; Nikita Voronkov; Alla Boshchenko; James Downey; Robert Mentzer Journal: Curr Cardiol Rev Date: 2021