title: Cyclosporine A protects against arachidonic acid toxicity in rat hepatocytes: role of CYP2E1 and mitochondria.
abstract: Diets high in polyunsaturated fatty acids (PUFA) are important for the development of alcoholic liver injury. The goal of this report was to characterize toxicity by arachidonic acid (AA), its enhancement by salicylate, and the role of mitochondrial injury in the pathway leading to toxicity in hepatocytes from pyrazole-treated rats. AA caused toxicity that was increased by sodium salicylate. This synergistic toxicity was reduced by diallyl sulfide (DAS), an inhibitor of CYP2E1; Trolox ([+/-] 6-hydroxy, 2, 5, 7, 8-tetramethylchroman-2-carboxylic acid), an inhibitor of lipid peroxidation; Z-Val-Ala-Asp(OMe)-fluoromethylketone (ZVAD-FMK), a pan caspase inhibitor; and by cyclosporine A (CsA), an inhibitor of the mitochondrial permeability transition. Mitochondrial membrane potential also was reduced, and this was prevented by cyclosporine, diallyl sulfide, and Trolox. There was release of mitochondrial cytochrome c into the cytosol and activation of caspase 3, which were prevented by cyclosporine, diallylsulfide, and Trolox. Toxicity was prevented by expression of catalase either in the cytosolic or the mitochondrial compartment. Levels of CYP2E1 rapidly declined, and this was partially prevented by salicylate. These results are consistent with a model in which CYP2E1-dependent production of reactive oxygen species enhances lipid peroxidation when AA is added to hepatocytes. This results in damage to the mitochondria, with initiation of a membrane permeability transition and a decline in membrane potential, followed by release of cytochrome c, caspase 3 activation, and cellular toxicity. In conclusion, damage to mitochondria appears to play an important role in the CYP2E1 plus AA toxicity.
authors.affiliation: Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York University, New York, NY 10029, USA.
authors.forename: Defeng
authors.initials: D
authors.lastname: Wu
authors.forename: Arthur I
authors.initials: AI
authors.lastname: Cederbaum
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000498:Allyl Compounds / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D016718:Arachidonic Acid / Q000633:toxicity*; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D002839:Chromans / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology*; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000633:toxicity; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012459:Salicylates / Q000494:pharmacology; D013440:Sulfides / Q000494:pharmacology
chemical_list: D000498:Allyl Compounds; D000975:Antioxidants; D061945:Caspase Inhibitors; D002839:Chromans; D016861:Cyclooxygenase Inhibitors; D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D012459:Salicylates; D013440:Sulfides; D016718:Arachidonic Acid; C038491:allyl sulfide; D016572:Cyclosporine; D000255:Adenosine Triphosphate; D002374:Catalase; D019392:Cytochrome P-450 CYP2E1; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid