The role of thiols in mitochondrial susceptibility to iron and tert-butyl hydroperoxide-mediated toxicity in cultured mouse hepatocytes.
Cultured hepatocytes derived from the newborn mutant c14CoS/c14CoS mouse (14CoS/14CoS cells) have 3-fold higher levels of reduced glutathione (GSH) and greater resistance to menadione toxicity than hepatocytes derived from the wild-type cch/cch mouse (ch/ch cells). Therefore, we used these cell lines to examine mechanisms of oxidative stress produced by iron and tert-butyl hydroperoxide (TBHP). Both cell types were resistant to 25 microM Fe2+ toxicity in the absence of added TBHP. However, in the presence of Fe2+, striking differences in susceptibility to TBHP toxicity between the cell types were observed. With 25 microM Fe2+, ch/ch cells showed TBHP concentration-dependent toxicity, with total lethality at 500 microM; in contrast, 14CoS/14CoS cells were completely resistant to the lethal effects of this concentration of TBHP. Concentration-dependent TBHP-mediated increases in cytosolic Ca2+, pH, and GSSG/GSH ratios, and decreases in GSH levels, were evident in ch/ch cells. 14CoS/14CoS cells exhibited concentration-dependent TBHP-mediated changes in GSH and GSSG/GSH ratios, but cytosolic Ca2+ and pH remained at control levels. Mitochondrial GSH pools were also diminished by TBHP, although there was no selective depletion; mitochondrial GSH remained at about 14% of total cellular GSH. Both cell types exhibited the same time-dependent decrease in plasma membrane protein thiols and a time-dependent increase in plasma membrane protein carbonyls. However, only ch/ch cells displayed a time-dependent depletion of mitochondrial protein thiols, concomitant with an increase in mitochondrial protein carbonyls, while 14CoS/14CoS cells were resistant to such changes. All of the effects produced by TBHP were prevented by desferoxamine.(ABSTRACT TRUNCATED AT 250 WORDS)
Shertzer
H G
HG
Department of Environmental Health, University of Cincinnati Medical Center, Ohio 45267-0056.
Bannenberg
G L
GL
Zhu
H
H
Liu
R M
RM
Moldéus
P
P
D000818:Animals; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D056486:Chemical and Drug Induced Liver Injury / Q000503:physiopathology*; D004247:DNA / Q000737:chemistry; D005978:Glutathione / Q000378:metabolism; D007501:Iron / Q000633:toxicity*; D015227:Lipid Peroxidation / Q000187:drug effects; D051379:Mice; D008856:Microscopy, Fluorescence; D008930:Mitochondria, Liver / Q000187:drug effects*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000633:toxicity*; D013050:Spectrometry, Fluorescence; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D020122:tert-Butylhydroperoxide
D010545:Peroxides; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D004247:DNA; D020122:tert-Butylhydroperoxide; D007501:Iron; D005978:Glutathione; D002118:Calcium