Mitochondrial K(ATP) channels-derived reactive oxygen species activate pro-survival pathway in pravastatin-induced cardioprotection.
Reactive oxygen species (ROS) are important intracellular signaling molecules and are implicated in cardioprotective pathways including ischemic preconditioning. Statins have been shown to have cardioprotective effects against ischemia/reperfusion injury, however, the precise mechanisms remain to be elucidated. We hypothesized that ROS-mediated signaling cascade may be involved in pravastatin-induced cardioprotection. Cultured rat cardiomyocytes were exposed to H(2)O(2) for 30 min to induce cell injury. Pravastatin significantly suppressed H(2)O(2)-induced cell death evaluated by propidium iodide staining and the MTT assay. Incubation with pravastatin activated catalase, and prevented a ROS burst induced by H(2)O(2), which preserved mitochondrial membrane potential. Protective effects were induced very rapidly within 10 min, which was concordant with the up-regulation of phosphorylated ERK1/2. L-NAME, 5HD, N-acetylcysteine (NAC) and staurosporine inhibited ERK1/2 phosphorylation and also reduced pravastatin-induced cardioprotection, suggesting NO, mitochondrial K(ATP) (mitoK(ATP)) channels, ROS and PKC should be involved in the cardioprotective signaling. We also demonstrated that pravastatin moderately up-regulated ROS generation in a 5HD-inhibitable manner. In isolated perfused rat heart experiments, pravastatin administered 10 min prior to no-flow global ischemia significantly improved left ventricular functional recovery, and also reduced infarct size, which were attenuated by the treatment with NAC, 5HD, L-NAME or staurosporine. Administration of pravastatin from the beginning of reperfusion also conferred cardioprotection. Pravastatin protected the cardiomyocytes against oxidative stress by preventing the ROS burst and preserving mitochondrial function. Moderately up-regulated ROS production by mitoK(ATP) channels opening is involved in the pro-survival signaling cascade activated by pravastatin.
Department of Laboratory Examination and Diagnostics, Oita University, Yufu-city, Japan.
Luong Cong
LC
Thuc
Yasushi
Y
Teshima
Naohiko
N
Takahashi
Yasuko
Y
Nagano-Torigoe
Kaori
K
Ezaki
Kunio
K
Yufu
Mikiko
M
Nakagawa
Masahide
M
Hara
Tetsunori
T
Saikawa
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*; D017035:Pravastatin / Q000494:pharmacology*; D020011:Protective Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*
D015221:Potassium Channels; D020011:Protective Agents; D017382:Reactive Oxygen Species; C117780:mitochondrial K(ATP) channel; D017035:Pravastatin