Brief exposure to carbon monoxide preconditions cardiomyogenic cells against apoptosis in ischemia-reperfusion.
We examined whether and how pretreatment with carbon monoxide (CO) prevents apoptosis of cardioblastic H9c2 cells in ischemia-reperfusion. Reperfusion (6 h) following brief ischemia (10 min) induced cytochrome c release, activation of caspase-9 and caspase-3, and apoptotic nuclear condensation. Brief CO pretreatment (10 min) or a caspase-9 inhibitor (Z-LEHD-FMK) attenuated these apoptotic changes. Ischemia-reperfusion increased phosphorylation of Akt at Ser472/473/474, and this was enhanced by CO pretreatment. A specific Akt inhibitor (API-2) blunted the anti-apoptotic effects of CO in reperfusion. In normoxic cells, CO enhanced O2(-) generation, which was inhibited by a mitochondrial complex III inhibitor (antimycin A) but not by a NADH oxidase inhibitor (apocynin). The CO-enhanced Akt phosphorylation was suppressed by an O2(-) scavenger (Tiron), catalase or a superoxide dismutase (SOD) inhibitor (DETC). These results suggest that CO pretreatment induces mitochondrial generation of O2(-), which is then converted by SOD to H2O2, and subsequent Akt activation by H2O2 attenuates apoptosis in ischemia-reperfusion.
Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Mihoko
M
Kondo-Nakamura
Kaori
K
Shintani-Ishida
Koichi
K
Uemura
Ken-ichi
K
Yoshida
D017209:Apoptosis / Q000187:drug effects*; D002248:Carbon Monoxide / Q000494:pharmacology*; D002460:Cell Line; D019610:Cytoprotection; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D032386:Myoblasts, Cardiac / Q000187:drug effects*; D010100:Oxygen / Q000494:pharmacology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015427:Reperfusion Injury / Q000517:prevention & control*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D002248:Carbon Monoxide; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases; D010100:Oxygen