title: Pivotal role of mitochondrial Ca(2+) in microcystin-induced mitochondrial permeability transition in rat hepatocytes.
abstract: We have shown earlier that microcystin-LR (MLR), a specific hepatotoxin, induced onset of mitochondrial permeability transition (MPT) and apoptosis in rat hepatocytes. Here we attempted to investigate the role of mitochondrial Ca(2+) in MLR-induced onset of MPT and cell death. Using confocal microscopy, we found that MLR caused an early surge of mitochondrial Ca(2+) prior to the onset of MPT and cell death. Pretreatment with 1,2-bis(O-aminophenoxyl)ethane-N,N,N',N'-tetracetic acid tetra(acetoxymethyl)ester (an intracellular Ca(2+) chelator) or ruthenium red (an inhibitor of mitochondrial Ca(2+) uniporter) prevented the early mitochondrial Ca(2+) surge and attenuated the subsequent onset of MPT and cell death. On the other hand, a mitochondrial uncoupler, CCCP, rapidly disrupted the mitochondrial membrane potential and also prevented the mitochondrial Ca(2+) surge, onset of MPT, and cell death. We thus conclude that mitochondrial Ca(2+) plays an important role in the onset of MPT and cell death in MLR-treated rat hepatocytes.
authors.affiliation: Department of Community, Occupational, and Family Medicine, Faculty of Medicine (MD3), National University of Singapore, 16 Medical Drive, Singapore, 117597, Singapore.
authors.forename: W X
authors.initials: WX
authors.lastname: Ding
authors.forename: H M
authors.initials: HM
authors.lastname: Shen
authors.forename: C N
authors.initials: CN
authors.lastname: Ong
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D002135:Calcium-Binding Proteins / Q000037:antagonists & inhibitors; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D019610:Cytoprotection / Q000187:drug effects; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D007473:Ion Channels; D008297:Male; D008387:Marine Toxins; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism; D052998:Microcystins; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D010456:Peptides, Cyclic / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D012430:Ruthenium Red / Q000494:pharmacology
chemical_list: D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D007473:Ion Channels; D008387:Marine Toxins; D008565:Membrane Proteins; D052998:Microcystins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D010456:Peptides, Cyclic; D017382:Reactive Oxygen Species; C034703:mitochondrial calcium uniporter; D012430:Ruthenium Red; D004533:Egtazic Acid; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; C057862:cyanoginosin LR; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium