Effect of oxidative stress on SO4= uptake through band 3 protein in human erythrocytes

Human erythrocyte membrane consists of a lipid bilayer
and integral proteins, amongst which Band 3 protein (B3p)
playing a role in membrane deformability due to its cross link
with cytoplasmic proteins, is responsible for Cl-/HCO3-
exchange, reflecting on gas exchange efficiency. The effect of
oxidative stress in terms of lipid peroxidation, -SH groups oxidation,
anion exchange capability and phosphorylation of
Tyrosine residues of Bp3, modulating its function, has been
here considered. Oxidative conditions have been induced by
exposure to either H2O2 or CdCl2 or NEM (N-ethylamelimide),
with or without antioxidants such as Curcumin, Melatonin or
MgCl2. The efficiency of B3p has been verified by measuring
the rate constant for SO4= uptake, more easily estimated than
Cl- transport, while oxidative status was assessed by determining
levels of MDA (malonyldialdehyde), membrane –SH
groups and intracellular GSH (reduced glutathione). B3p
expression levels have been also measured. Our results show
that the exposure to all oxidative compounds used for the
present protocol reduced SO4= uptake via different mechanisms,
as H2O2-induced damage was dependent neither on
MDA production, nor on –SH groups and GSH levels reduction,
contrarily to the other oxidants, while B3p expression levels
were reduced after treatment with each oxidant.
Moreover, phosphorylative pathways are involved in this
inhibitory effect which is reversed by antioxidants. In conclusion,
SO4= uptake may be suggested as a tool to monitor erythrocytes
function under oxidative conditions possibly deriving
from environment (food, water, enspired air) and B3p may be
a candidate for pharmacological targeting against oxidative
stress-related pathologies.