Pyruvate protection against endothelial cytotoxicity induced by blockade of glucose uptake.
We have previously demonstrated that the redox reactant pyruvate prevents apoptosis in the oxidant model of bovine pulmonary artery endothelial cells (BPAEC), and that the anti-apoptotic mechanism of pyruvate is mediated in part via the mitochondrial matrix compartment. However, cytosolic mechanisms for the cytoprotective feature of pyruvate remain to be elucidated. This study investigated the pyruvate protection against endothelial cytotoxicity when the glycolysis inhibitor 2-deoxy-D-glucose (2DG) was applied to BPAEC. Millimolar 2DG blocked the cellular glucose uptake in a concentration- and time-dependent manner with >85% inhibition at > or =5 mM within 24 h. The addition of 2DG evoked BPAEC cytotoxicity with a substantial increase in lipid peroxidation and a marked decrease in intracellular total glutathione. Exogenous pyruvate partially prevented the 2DG-induced cell damage with increasing viability of BPAEC by 25-30%, and the total glutathione was also modestly increased. In contrast, 10 mM L-lactate, as a cytosolic reductant, had no effect on the cytotoxicity and lipid peroxidation that are evoked by 2DG. These results suggest that 2DG toxicity may be a consequence of the diminished potential of glutathione antioxidant, which was partially restored by exogenous pyruvate but not L-lactate. Therefore, pyruvate qualifies as a cytoprotective agent for strategies that attenuate the metabolic dysfunction of the endothelium, and cellular glucose oxidation is required for the functioning of the cytosolic glutathione/NADPH redox system.
Division of Life Sciences and Silver Biotechnology Research Center, Hallym University, Chuncheon 200-702, Korea.
Se-Jin
SJ
Chung
Se-Hee
SH
Lee
Yong-Jin
YJ
Lee
Hyoung-Sook
HS
Park
Rolf
R
Bünger
Young-Hee
YH
Kang
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects*; D003600:Cytosol / Q000378:metabolism; D003847:Deoxyglucose / Q000494:pharmacology / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005947:Glucose / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005978:Glutathione / Q000187:drug effects; D007700:Kinetics; D019344:Lactic Acid / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D011651:Pulmonary Artery / Q000166:cytology; D019289:Pyruvic Acid / Q000378:metabolism* / Q000494:pharmacology; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D019344:Lactic Acid; D019289:Pyruvic Acid; D003847:Deoxyglucose; D005978:Glutathione; D005947:Glucose