Role of calcium and cyclophilin D in the regulation of mitochondrial permeabilization induced by glutathione depletion.
The mitochondrial permeability transition (MPT) is a calcium and oxidative stress sensitive transition in the permeability of the mitochondrial inner membrane that plays a crucial role in cell death. However, the mechanism regulating the MPT remains controversial. To study the role of oxidative stress in the regulation of the MPT, we used diethyl maleate (DEM) to deplete glutathione (GSH) in human leukemic CEM cells. GSH depletion increased mitochondrial calcium and reactive oxygen species (ROS) levels in a co-dependent manner causing loss of mitochondrial membrane potential (deltapsi(m)) and cell death. These events were inhibited by the calcium chelator BAPTA-AM and the antioxidants N-acetylcysteine (NAC) and the triphenyl phosphonium-linked ubiquinone derivative MitoQ. In contrast, the MPT inhibitor cyclosporine A (CsA) and small interference RNA (siRNA) knockdown of cyclophilin D (Cyp-D) were not protective. These results indicate that mitochondrial permeabilization induced by GSH depletion is not regulated by the classical MPT.
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Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore.
Armstrong
J S
JS
D000111:Acetylcysteine / Q000494:pharmacology; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016572:Cyclosporine / Q000494:pharmacology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005434:Flow Cytometry; D016166:Free Radical Scavengers / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology*; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010539:Permeability; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D014162:Transfection; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000494:pharmacology
D002614:Chelating Agents; D000081406:Peptidyl-Prolyl Isomerase F; D016166:Free Radical Scavengers; D009943:Organophosphorus Compounds; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D014451:Ubiquinone; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C429014:mitoquinone; D004533:Egtazic Acid; D016572:Cyclosporine; D021983:Cyclophilins; D005978:Glutathione; D002118:Calcium; D000111:Acetylcysteine