TY - JOUR
T1 - Oxidative stress causes membrane phospholipid rearrangement and shedding from RBC membranes-An NMR study
AU - Freikman, Inna
AU - Amer, Johnny
AU - Cohen, Jack S.
AU - Ringel, Israel
AU - Fibach, Eitan
PY - 2008/10
Y1 - 2008/10
N2 - Nuclear Magnetic Resonance (NMR) spectroscopy was used to investigate the relationship between oxidative stress experienced by RBCs and their phospholipid content and shedding. Using 1H-NMR, we demonstrated a higher lactate/pyruvate ratio, an indicator of oxidative stress, in normal RBCs treated with oxidants (t-butylhydroxyperoxide and H2O2) as well as in β-thalassemic RBCs. Using 31P-NMR, we found 30% more phosphatidylcholine (PC), and unexpectedly, 35% less phosphatidylserine (PS) in the thalassemic RBCs. PS was decreased by treatment with oxidants and increased by anti-oxidants (vitamin C and N-acetyl cysteine); PC showed the opposite behavior. Thalassemic RBCs incubated in phosphate buffered saline produced more PS in the supernatant than normal RBCs. Anti-oxidants reduced the PS in the supernatant while oxidants increased it. Plasma of thalassemic patients contained 2.6-fold and 1.8-fold more PS and PC, respectively, than normal plasma. These results indicate that the decreased PS in RBCs resulted from increased shedding. The nature of the shed PS was studied by purifying and analyzing membranous microparticles from the plasma and RBC supernatants. More PS was found in microparticles purified from thalassemic plasma and RBC supernatants (5.6- and 4.8-fold, respectively) than in their normal counterparts. However, the bulk (80-90%) of the shed PS was not associated with microparticles. The significance of PS shedding for RBC survival needs further clarification.
AB - Nuclear Magnetic Resonance (NMR) spectroscopy was used to investigate the relationship between oxidative stress experienced by RBCs and their phospholipid content and shedding. Using 1H-NMR, we demonstrated a higher lactate/pyruvate ratio, an indicator of oxidative stress, in normal RBCs treated with oxidants (t-butylhydroxyperoxide and H2O2) as well as in β-thalassemic RBCs. Using 31P-NMR, we found 30% more phosphatidylcholine (PC), and unexpectedly, 35% less phosphatidylserine (PS) in the thalassemic RBCs. PS was decreased by treatment with oxidants and increased by anti-oxidants (vitamin C and N-acetyl cysteine); PC showed the opposite behavior. Thalassemic RBCs incubated in phosphate buffered saline produced more PS in the supernatant than normal RBCs. Anti-oxidants reduced the PS in the supernatant while oxidants increased it. Plasma of thalassemic patients contained 2.6-fold and 1.8-fold more PS and PC, respectively, than normal plasma. These results indicate that the decreased PS in RBCs resulted from increased shedding. The nature of the shed PS was studied by purifying and analyzing membranous microparticles from the plasma and RBC supernatants. More PS was found in microparticles purified from thalassemic plasma and RBC supernatants (5.6- and 4.8-fold, respectively) than in their normal counterparts. However, the bulk (80-90%) of the shed PS was not associated with microparticles. The significance of PS shedding for RBC survival needs further clarification.
KW - Membrane phospholipids
KW - NMR
KW - Oxidative stress
KW - RBC
KW - Thalassemia
UR - http://www.scopus.com/inward/record.url?scp=52049090128&partnerID=8YFLogxK
U2 - 10.1016/j.bbamem.2008.06.008
DO - 10.1016/j.bbamem.2008.06.008
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C2 - 18621018
AN - SCOPUS:52049090128
SN - 0005-2736
VL - 1778
SP - 2388
EP - 2394
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 10
ER -