Antibiotic effects on SO uptake in human erythrocytes

Abstract

The erythrocyte is a cell highly exposed to oxygen pressure that, in turn, provokes oxidative stress involving loss of SH-groups, cell shrinkage by activation of K(+)-Cl(-) cotransport (KCC) and membrane destabilization which plays an important role in the premature haemolysis of red blood cells (RBCs). Oxidative stress provoked by chemicals frequently occurs in human erythrocytes. The aim of this study was to test whether the antibiotics alter the redox state and investigate their influences on band 3 protein that is involved in the facilitated electro neutral exchange of Cl(-) for HCO(3)(-) across the membrane of mammalian erythrocytes. Normal erythrocytes were treated with some antibiotics and thiol oxidizing agent N-ethylmaleimide (NEM) and tested for sulphate uptake, K(+) efflux and for glutathione (GSH) concentration as an index of oxidative stress. The rate constant of SO(4)(=) uptake measured in erythrocytes treated with antibiotics as well as NEM was decreased with respect to control cells as a result of band 3 SH-groups oxidation or the stress-induced K(+)-Cl(-) symport-mediated cell shrinkage. In fact, this hypothesis was verified by increased K(+) efflux and decreased GSH values measured in treated erythrocytes compared to controls.

Pharmacological properties of indolone-N-oxides controlled by a bioreductive transformation in red blood cells?

“…Thus, the incubation of RBCs with CDNB results in the rapid irreversible depletion of GSH and oxidation of large amounts of haemoglobin to methaemoglobin. N-Ethylmaleimide (NEM) is a known sulfhydryl-blocking agent [18][19][20] and has been used in the same way, to deplete thiols from the cells. Fig.…”

N-ethylmaleimide activates a Cl−-independent component of K+ flux in mouse erythrocytes

“…Among the human erythrocyte transport activities inhibited by mM NEM are 45 Ca 2+ uptake induced by plasmalemmal Ca 2+ -ATPase inhibitor vanadate [48], the nonselective voltage-dependent cation conductance [49], sulfate transport [50], low affinity cationic amino acid transport (system y+L) [51], and equilibrative nucleobase transport [52]. Multiple transport systems may be indirectly modulated by NEM’s promotion of the tetramer-to-dimer transition of spectrin, attributed to weakened interaction of ankyrin with AE1/Band 3 [53]; by NEM’s activation of phospholipid scramblase, inhibition of aminophospholipid translocase (flippase), and the NEM-associated reduced Ca 2+ requirement for phospholipid scrambling in both mouse and human erythrocytes [54]; by NEM’s inhibition of erythroid pertussis toxin-sensitive G proteins [55; 56; 57]; by NEM’s inhibition of serine phosphatases PP1 and PP2A [58]; by NEM’s enhanced plasma membrane translocation of calpain-1 [59] and of tyrosine phosphatase SHP1 (independent of Band 3 tyrosine phosphorylation) [60]; and by NEM’s inhibition of calpain at multi-mM concentrations [61].…”

Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions

“…Particularly, the aim of the present study was to assess the anion transport, through the measurement of the sulfate uptake using different experimental temperatures and buffer solutions, and the different physiological behaviour in band 3 protein implicated in the facilitated electroneutral exchange of Cl − for HCO 3 − across the membrane of equine RBCs. Particularly, as previously demonstrated, these cells were used for measuring the slower and better controllable SO 4 = uptake (instead of the anions Cl − or HCO 3 − that penetrate the membrane approximately one million times faster).…”