Effect of glutathione redox state on Leydig cell susceptibility to acute oxidative stress.
The free radical, or oxidative stress, theory posits that imbalance in cells between prooxidants and antioxidants results in an altered redox state and, over time, an accumulation of oxidative damage. We hypothesized herein that cells with an increasingly prooxidant intracellular environment also might be particularly susceptible to acute oxidative stress. To test this hypothesis, MA-10 cells were used as a model because of their well-defined, measurable function, namely progesterone production. We first experimentally altered the redox environment of the cells by their incubation with buthionine sulfoximine (BSO) or diethyl maleate (DEM) so as to deplete glutathione (GSH), and then exposed the GSH-depleted cells acutely to the prooxidant tert-butyl hydroperoxide (t-BuOOH). Neither BSO nor DEM by themselves affected progesterone production. However, when the GSH-depleted cells subsequently were exposed acutely to t-BuOOH, intracellular reactive oxygen species concentration was significantly increased, and this was accompanied by significant reductions in progesterone production. In striking contrast, treatment of control cells with t-BuOOH had no effect. Depletion of GSH and subsequent treatment of the cells with t-BuOOH-induced the phosphorylation of each of ERK1/2, JNK and p38, members of the MAPK family. Inhibition of p38 phosphorylation largely prevented the t-BuOOH-induced down-regulation of progesterone production in GSH-depleted cells. These results suggest that, as hypothesized, alteration of the intracellular GSH redox environment results in the increased sensitivity of MA-10 cells to oxidative stress, and that this is mediated by activation of one or more redox-sensitive MAPK members.
Chen
Haolin
H
Division of Reproductive Biology, Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA. hchen@jhsph.edu
Zhou
Liang
L
Lin
Chieh-Yin
CY
Beattie
Matthew C
MC
Liu
June
J
Zirkin
Barry R
BR
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002460:Cell Line / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007985:Leydig Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D008298:Maleates / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011374:Progesterone / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
D000975:Antioxidants; D004791:Enzyme Inhibitors; D008298:Maleates; D016877:Oxidants; D017382:Reactive Oxygen Species; D011374:Progesterone; D019328:Buthionine Sulfoximine; D020122:tert-Butylhydroperoxide; D000242:Cyclic AMP; D020928:Mitogen-Activated Protein Kinases; C014476:diethyl maleate; D005978:Glutathione