Abstract
Glycolysis is an essential metabolic pathway for survival of red blood cells (RBC), and mutations in the RBC-type of pyruvate kinase (R-PK) cause hereditary non-spherocytic hemolytic anemia. We have shown that R-PK deficiency induced apoptosis in erythroid progenitor cells (
Blood 96:596a, 2000
; Am J Hematol 74: 68, 2003
). In this study, we examined whether ex vivo treatment of erythroid cells with high concentration of glycolytic intermediates ameliorated apoptosis of R-PK deficiency. For this purpose, we used the R-PK deficient Friend erythroleukemic cell, SLC3, which has been established from a mice model of R-PK deficiency (Jpn J Cancer Res 90: 171, 1999
). SLC3 and a control Friend cell were cultured with 0, 1, 3, and 5mM phosphoenolpyruvate (PEP) or pyruvate (PA). Supplementations of either PEP or PA resulted in about 2-fold accumulation of intracellular PA; however, ATP concentration was not significantly changed. Flow cytometric analysis showed that 24-hours treatment with 5mM PEP significantly reduced annexinV (+)/PI (−) cells. These data suggested that exogenously supplemented glycolytic intermediates increased intracellular PA concentration, resulting in amelioration of erythroid apoptosis. We have shown that a glutathione precursor, N-acetyl cysteine, reduced apoptosis of SLC3. Several studies revealed that PA, which effectively maintained the redox state and also prevented the loss of intracellular antioxidants, antagonized the apoptotic cell death. Taken together, oxidative stress caused by decreased supply of PA might account for erythroid apoptosis due to R-PK deficiency.Author notes
Corresponding author
2005, The American Society of Hematology
2004
