title: H2O2-Induced Oxidative Stress Affects SO4= Transport in Human Erythrocytes.
abstract: The aim of the present investigation was to verify the effect of H2O2-induced oxidative stress on SO4= uptake through Band 3 protein, responsible for Cl-/HCO3- as well as for cell membrane deformability, due to its cross link with cytoskeletal proteins. The role of cytoplasmic proteins binding to Band 3 protein has been also considered by assaying H2O2 effects on hemoglobin-free resealed ghosts of erythrocytes. Oxidative conditions were induced by 30 min exposure of human erythrocytes to different H2O2 concentrations (10 to 300 μM), with or without GSH (glutathione, 2 mM) or curcumin (10 μM), compounds with proved antioxidant properties. Since SO4= influx through Band 3 protein is slower and better controllable than Cl- or HCO3- exchange, the rate constant for SO4= uptake was measured to prove anion transport efficiency, while MDA (malondialdehyde) levels and -SH groups were estimated to quantify the effect of oxidative stress. H2O2 induced a significant decrease in rate constant for SO4= uptake at both 100 and 300 μM H2O2. This reduction, observed in erythrocytes but not in resealed ghosts and associated to increase in neither MDA levels nor in -SH groups, was impaired by both curcumin and GSH, whereas only curcumin effectively restored H2O2-induced changes in erythrocytes shape. Our results show that: i) 30 min exposure to 300 μM H2O2 reduced SO4= uptake in human erythrocytes; ii) oxidative damage was revealed by the reduction in rate constant for SO4= uptake, but not by MDA or -SH groups levels; iii) the damage was produced via cytoplasmic components which cross link with Band 3 protein; iv) the natural antioxidant curcumin may be useful in protecting erythrocytes from oxidative injury; v) SO4= uptake through Band 3 protein may be reasonably suggested as a tool to monitor erythrocytes function under oxidative conditions possibly deriving from alcohol consumption, use of drugs, radiographic contrast media administration, hyperglicemia or neurodegenerative diseases.
authors.affiliation: Department of Human and Social Sciences, University of Messina, Messina, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Morabito
authors.affiliation: BromaTech S.r.l., Giarre, Italy.
authors.forename: Orazio
authors.initials: O
authors.lastname: Romano
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Messina, Italy.
authors.forename: Giuseppa
authors.initials: G
authors.lastname: La Spada
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Messina, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Marino
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001692:Biological Transport; D002463:Cell Membrane Permeability; D048430:Cell Shape; D003474:Curcumin / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000648:ultrastructure; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007700:Kinetics; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D013431:Sulfates / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D013431:Sulfates; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D005978:Glutathione; D003474:Curcumin