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Sickle hemoglobin disturbs normal coupling between erythrocyte O2 content, glycolysis and antioxidant capacity
Author(s) -
Rogers Stephen Colin,
Ross Jerlinda,
D'Avig Andre,
Gibbons Lindsey,
Hassan Mojibade,
McLaughlin Dylan,
Griffin Sherraine,
Neumayr Tara,
DeBaun Malcom,
DeBaun Michael,
Doctor Allan
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1009.1
Subject(s) - chemistry , biochemistry , red blood cell , erythrocyte deformability , glutathione , oxidative stress , pentose phosphate pathway , oxidative phosphorylation , hemoglobin , glycolysis , biophysics , enzyme , biology
Energy metabolism in red blood cells (RBCs) is characterized by oxygen (O 2 )‐responsive variation in flux through the Embden Meyerhof Pathway (EMP) or the Hexose Monophosphate Pathway (HMP). As such, generation of ATP, NADH, and 2,3‐DPG (EMP) or NADPH (HMP) shifts with RBC O 2 content, due to competition between deoxy‐hemoglobin (Hb) and key EMP enzymes for binding to the cytoplasmic domain of the Band 3 membrane protein (cdB3). Enzyme inactivation by cdB3 sequestration in oxy RBCs favors HMP flux and NADPH generation (maximizing glutathione (GSH)‐based antioxidant systems). We hypothesized that sickle hemoglobin (HbS) disrupts cdB3‐based regulatory protein complex assembly, creating vulnerability to oxidative stress. In RBCs from patients with sickle cell anemia (SCA), we demonstrate constrained NADPH and GSH recycling and reduced resilience to oxidative stress. We further illustrate abnormal association of HbS to RBC membrane that interferes with sequestration/inactivation of the EMP enzyme GAPDH. These findings are confirmed by EMP/HMP 1 H NMR glucose flux analysis in addition to RBC immunofluorescent imaging during O 2 loading/unloading. Moreover, selective inhibition of inappropriately dispersed GAPDH rescues antioxidant capacity. Such disturbance of cdB3‐based linkage between O 2 gradients and RBC metabolism suggests a novel mechanism by which hypoxia may influence SCA phenotype.