Albumin permeability across endothelial cell monolayer exposed to reactive oxygen intermediates: involvement of reversible functional alteration of the cell membrane Ca2+ channels.
This study was designed to test the idea that the redox state of sulfhydryl (SH)-groups in cell-membrane Ca2+ channels plays a pivotal role in Ca2+ influx, which in turn causes an increase in albumin permeability across the cultured monolayer of porcine pulmonary artery endothelial (PPAE) cells exposed to xanthine/xanthine oxidase (X/XO). Albumin permeability as well as the concentration of intracellular Ca2+ ([Ca2+]i) was increased by X/XO. A H2O2 scavenger (catalase), an iron chelator (o-phenanthroline), and a hydroxyl radical scavenger (dimethyl sulfoxide) inhibited these changes provoked by X/XO, in which intracellular iron-catalyzed hydroxyl radical generation was suggested to be involved. The increase in albumin permeability and [Ca2+]i continued once the PPAE cells were exposed to X/XO. The [Ca2+]i was decreased by a Ca2+ channel blocker, Ni2+, while the removal of Ni2+ increased [Ca2+]i again, suggesting the sustained Ca2+ influx through cell-membrane Ca2+ channels was responsible for the [Ca2+]i elevation. Ni2+ failed to inhibit albumin permeability sustained after the removal of X/XO. In contrast, SH-reducing agents (dithiothreitol and glutathione) inhibited the sustained permeability as well as Ca2+ influx. We concluded that the redox alteration of SH-groups in cell-membrane Ca2+ channels was involved in the increase in albumin permeability after exposure of the endothelial cells to oxidative stress.
Saeki
N
N
Department of Anesthesiology and Critical Care Medicine, Hiroshima University School of Medicine, Japan.
AzMa
T
T
Fujii
K
K
Kawamoto
M
M
Yuge
O
O
D000418:Albumins / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000378:metabolism / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D009532:Nickel / Q000494:pharmacology; D010618:Phenanthrolines / Q000378:metabolism / Q000494:pharmacology; D011651:Pulmonary Artery / Q000166:cytology; D013552:Swine; D019820:Xanthine / Q000378:metabolism / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000378:metabolism / Q000494:pharmacology
D000418:Albumins; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002614:Chelating Agents; D016166:Free Radical Scavengers; D010618:Phenanthrolines; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D019820:Xanthine; D004533:Egtazic Acid; D009532:Nickel; D002374:Catalase; D014969:Xanthine Oxidase; D005978:Glutathione; D002118:Calcium; D004229:Dithiothreitol; C025205:1,10-phenanthroline; D004121:Dimethyl Sulfoxide