Oxidative stress causes membrane phospholipid rearrangement and shedding from RBC membranes-An NMR study

Inna Freikman, Johnny Amer, Jack S. Cohen, Israel Ringel, Eitan Fibach*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)2388-2394
Number of pages7
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1778
Issue number10
DOIs
StatePublished - Oct 2008

Keywords

  • Membrane phospholipids
  • NMR
  • Oxidative stress
  • RBC
  • Thalassemia

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