Pivotal Role of Mitochondrial Ca2+ in Microcystin-Induced Mitochondrial Permeability Transition in Rat Hepatocytes

2001 ◽  
Vol 285 (5) ◽  
pp. 1155-1161 ◽  
Author(s):  
Wen-Xing Ding ◽  
Han-Ming Shen ◽  
Choon-Nam Ong
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Rat Hepatocytes ◽  
Pivotal Role ◽  
Mitochondrial Permeability

scholarly journals Mitochondrial permeability transition in rat hepatocytes after anoxia/reoxygenation: role of Ca2+-dependent mitochondrial formation of reactive oxygen species

2012 ◽  
Vol 302 (7) ◽  
pp. G723-G731 ◽  
Author(s):  
Jae-Sung Kim ◽  
Jin-Hee Wang ◽  
John J. Lemasters
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Permeability Transition ◽  
Rat Hepatocytes ◽  
Oxygen Species ◽  
Mitochondrial Permeability ◽  
Ros Formation

Onset of the mitochondrial permeability transition (MPT) is the penultimate event leading to lethal cellular ischemia-reperfusion injury, but the mechanisms precipitating the MPT after reperfusion remain unclear. Here, we investigated the role of mitochondrial free Ca2+ and reactive oxygen species (ROS) in pH- and MPT-dependent reperfusion injury to hepatocytes. Cultured rat hepatocytes were incubated in anoxic Krebs-Ringer-HEPES buffer at pH 6.2 for 4 h and then reoxygenated at pH 7.4 to simulate ischemia-reperfusion. Some cells were loaded with the Ca2+ chelators, BAPTA/AM and 2-[(2-bis-[carboxymethyl]aono-5-methoxyphenyl)-methyl-6-methoxy-8-bis[carboxymethyl]aminoquinoline, either by a cold loading protocol for intramitochondrial loading or by warm incubation for cytosolic loading. Cell death was assessed by propidium iodide fluorometry and immunoblotting. Mitochondrial Ca2+, inner membrane permeability, membrane potential, and ROS formation were monitored with Rhod-2, calcein, tetramethylrhodamine methylester, and dihydrodichlorofluorescein, respectively. Necrotic cell death increased after reoxygenation. Necrosis was blocked by 1 μM cyclosporin A, an MPT inhibitor, and by reoxygenation at pH 6.2. Confocal imaging of Rhod-2, calcein, and dichlorofluorescein revealed that an increase of mitochondrial Ca2+ and ROS preceded onset of the MPT after reoxygenation. Intramitochondrial Ca2+ chelation, but not cytosolic Ca2+ chelation, prevented ROS formation and subsequent necrotic and apoptotic cell death. Reoxygenation with the antioxidants, desferal or diphenylphenylenediamine, also suppressed MPT-mediated cell death. However, inhibition of cytosolic ROS by apocynin or diphenyleneiodonium chloride failed to prevent reoxygenation-induced cell death. In conclusion, Ca2+-dependent mitochondrial ROS formation is the molecular signal culminating in onset of the MPT after reoxygenation of anoxic hepatocytes, leading to cell death.

scholarly journals Calcium preconditioning inhibits mitochondrial permeability transition and apoptosis

2001 ◽  
Vol 280 (2) ◽  
pp. H899-H908 ◽  
Author(s):  
Meifeng Xu ◽  
Yigang Wang ◽  
Kyoji Hirai ◽  
Ahmar Ayub ◽  
Muhammad Ashraf
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Adenine Nucleotide ◽  
Permeability Transition ◽  
Cytochrome C Release ◽  
Mitochondrial Permeability ◽  
Lactate Dehydrogenase Release ◽  
Viable Cells ◽  
Reoxygenation Injury ◽  
Injury Protection

We tested the hypothesis whether calcium preconditioning (CPC) reduces reoxygenation injury by inhibiting mitochondrial permeability transition (MPT). Cultured myocytes were preconditioned by a brief exposure to 1.5 mM calcium (CPC) and subjected to 3 h of anoxia followed by 2 h of reoxygenation (A-R). Myocytes were also treated with 0.2 μM/l cyclosporin A (CsA), an inhibitor of MPT, before A-R. A significant increase of viable cells and reduced lactate dehydrogenase release was observed both in CPC- and CsA-treated myocytes compared with the A-R group. Cytochrome c release was predominantly observed in the cytoplasm of myocytes in the A-R group in contrast with CPC- or CsA-treated groups, where it was restricted only to mitochondria. Similarly, the cell death by apoptosis was also markedly attenuated in these groups. Electron-dense Ca2+ deposits in mitochondria were also less frequent. Atractyloside (20 μM/l), an adenine nucleotide translocase inhibitor, caused changes similar to those in the A-R group, suggesting a role of MPT in A-R injury. Protection by inhibition of MPT by CsA and CPC suggests that MPT plays an important role in reoxygenation/reperfusion injury. The data further suggest that preconditioning inhibits MPT by inhibiting Ca2+accumulation by mitochondria.

scholarly journals Xenon Preconditioning: The Role of Prosurvival Signaling, Mitochondrial Permeability Transition and Bioenergetics in Rats

2009 ◽  
Vol 108 (3) ◽  
pp. 858-866 ◽  
Author(s):  
Yasushi Mio ◽  
Yon Hee Shim ◽  
Ebony Richards ◽  
Zeljko J. Bosnjak ◽  
Paul S. Pagel ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Mitochondrial Permeability
Sign in / Sign up

Export Citation Format

Share Document