Authors: Yuliya V Kucherenko Lisa WagnerBritz Ingolf Bernhardt Florian Lang
Publish Date: 2013/02/22
Volume: 246, Issue: 4, Pages: 315-326
Abstract
DIDS NPPB tannic acid TA and AO1 are widely used inhibitors of Cl– channels Some Cl– channel inhibitors NPPB DIDS niflumic acid were shown to affect phosphatidylserine PS scrambling and thus the life span of human red blood cells hRBCs Since a number of publications suggest Ca2+ dependence of PS scrambling we explored whether inhibitors of Cl– channels DIDS NPPB or of Ca2+activated Cl− channels DIDS NPPB TA AO1 modified intracellular free Ca2+ concentration Ca2+i and activity of Ca2+activated K+ Gardos channel in hRBCs According to Fluo3 fluorescence in flow cytometry a short treatment 15 min +37 °C with Cl− channels inhibitors decreased Ca2+i in the following order TA AO1 DIDS NPPB According to forward scatter the decrease of Ca2+i was accompanied by a slight but significant increase in cell volume following DIDS NPPB and AO1 treatments TA treatment resulted in cell shrinkage According to wholecell patchclamp experiments TA activated and NPPB and AO1 inhibited Gardos channels The Cl– channel blockers further modified the alterations of Ca2+i following ATP depletion glucose deprivation iodoacetic acid 6inosine oxidative stress 1 mM tBHP and treatment with Ca2+ ionophore ionomycin 1 μM The ability of the Cl− channel inhibitors to modulate PS scrambling did not correlate with their influence on Ca2+i as TA and AO1 had a particularly strong decreasing effect on Ca2+i but at the same time enhanced PS exposure In conclusion Cl– channel inhibitors affect Gardos channels influence Ca2+ homeostasis and induce PS exposure of hRBCs by Ca2+independent mechanisms
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