TY - JOUR
T1 - Sickle hemoglobin disturbs normal coupling among erythrocyte O2 content, glycolysis, and antioxidant capacity
AU - Rogers, Stephen C.
AU - Ross, Jerlinda G.C.
AU - D'Avignon, Andre
AU - Gibbons, Lindsey B.
AU - Gazit, Vered
AU - Hassan, Mojibade N.
AU - McLaughlin, Dylan
AU - Griffin, Sherraine
AU - Neumayr, Tara
AU - DeBaun, Malcolm
AU - DeBaun, Michael R.
AU - Doctor, Allan
PY - 2013/2/28
Y1 - 2013/2/28
N2 - Energy metabolism in RBCs is characterized by O2-responsive variations in flux through the Embden Meyerhof pathway (EMP) or the hexose monophosphate pathway (HMP). Therefore, the generation of ATP, NADH, and 2,3-DPG (EMP) or NADPH (HMP) shift with RBC O2 content because of competition between deoxyhemoglobin and key EMP enzymes for binding to the cytoplasmic domain of the Band 3 membrane protein (cdB3). Enzyme inactivation by cdB3 sequestration in oxygenated RBCs favors HMP flux and NADPH generation (maximizing glutathione-based antioxidant systems). We tested the hypothesis that sickle hemoglobin disrupts cdB3-based regulatory protein complex assembly, creating vulnerability to oxidative stress. In RBCs from patients with sickle cell anemia, we demonstrate in the present study constrained HMP flux, NADPH, and glutathione recycling and reduced resilience to oxidative stress manifested by membrane protein oxidation and membrane fragility. Using a novel, inverted membrane-on-bead model, we illustrate abnormal (O2-dependent) association of sickle hemoglobin to RBC membrane that interferes with sequestration/inactivation of the EMP enzyme GAPDH. This finding was confirmed by immunofluorescent imaging during RBC O2 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 the sickle cell anemia phenotype.
AB - Energy metabolism in RBCs is characterized by O2-responsive variations in flux through the Embden Meyerhof pathway (EMP) or the hexose monophosphate pathway (HMP). Therefore, the generation of ATP, NADH, and 2,3-DPG (EMP) or NADPH (HMP) shift with RBC O2 content because of competition between deoxyhemoglobin and key EMP enzymes for binding to the cytoplasmic domain of the Band 3 membrane protein (cdB3). Enzyme inactivation by cdB3 sequestration in oxygenated RBCs favors HMP flux and NADPH generation (maximizing glutathione-based antioxidant systems). We tested the hypothesis that sickle hemoglobin disrupts cdB3-based regulatory protein complex assembly, creating vulnerability to oxidative stress. In RBCs from patients with sickle cell anemia, we demonstrate in the present study constrained HMP flux, NADPH, and glutathione recycling and reduced resilience to oxidative stress manifested by membrane protein oxidation and membrane fragility. Using a novel, inverted membrane-on-bead model, we illustrate abnormal (O2-dependent) association of sickle hemoglobin to RBC membrane that interferes with sequestration/inactivation of the EMP enzyme GAPDH. This finding was confirmed by immunofluorescent imaging during RBC O2 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 the sickle cell anemia phenotype.
UR - http://www.scopus.com/inward/record.url?scp=84876478466&partnerID=8YFLogxK
U2 - 10.1182/blood-2012-02-414037
DO - 10.1182/blood-2012-02-414037
M3 - Article
C2 - 23297128
AN - SCOPUS:84876478466
SN - 0006-4971
VL - 121
SP - 1651
EP - 1662
JO - Blood
JF - Blood
IS - 9
ER -