Glucose-6-phosphate dehydrogenase plays a crucial role in protection from redox-stress-induced apoptosis.
Glucose-6-phosphate dehydrogenase-deleted embryonic stem (ES) cells (G6pd Delta) proliferate in vitro without special requirements, but when challenged with oxidants fail to sustain glutathione disulphide reconversion to reduced glutathione (GSH), entering a condition of oxidative stress. Here, we investigate the signalling events downstream of GSH oxidation in G6pd Delta and wild-type (wt) ES cells. We found that G6pd Delta ES cells are very sensitive to oxidants, activating an apoptotic pathway at oxidant concentrations otherwise sublethal for wt ES cells. We show that the apoptotic pathway activated by low oxidant concentrations is accompanied by mitochondria dysfunction, and it is therefore blocked by the overexpression of Bcl-X(L). Bcl-X(L) does not inhibit the decrease in cellular GSH and reactive oxygen species formation following oxidant treatment. We also found that oxidant treatment in ES cells is followed by the activation of the MEK/extracellular signal-regulated kinase (ERK) pathway. Interestingly, ERK activation has opposite outcomes in G6pd Delta ES cells compared to wt, which has a proapoptotic function in the first and a prosurvival function in the latter. We show that this phenomenon can be regulated by the cellular GSH level.
Fico
A
A
Institute of Genetics and Biophysics, Adriano Buzzati Traverso, CNR, Via Marconi 10, Naples 80125, Italy. filosa@iigb.na.cnr.it
Paglialunga
F
F
Cigliano
L
L
Abrescia
P
P
Verde
P
P
Martini
G
G
Iaccarino
I
I
Filosa
S
S
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D020169:Caspases; D003958:Diamide / Q000494:pharmacology; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D051020:bcl-X Protein
C494812:Bcl2l1 protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D013439:Sulfhydryl Reagents; D051020:bcl-X Protein; D003958:Diamide; D005954:Glucosephosphate Dehydrogenase; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D020169:Caspases; D005978:Glutathione