TY - JOUR
T1 - The antibacterial activity of human neutrophils and eosinophils requires proton channels but not BK channels
AU - Femling, Jon K.
AU - Cherny, Vladimir V.
AU - Morgan, Deri
AU - Rada, Balázs
AU - Davis, A. Paige
AU - Czirják, Gabor
AU - Enyedi, Peter
AU - England, Sarah K.
AU - Moreland, Jessica G.
AU - Ligeti, Erzsébet
AU - Nauseef, William M.
AU - DeCoursey, Thomas E.
PY - 2006/6
Y1 - 2006/6
N2 - Electrophysiological events are of central importance during the phagocyte respiratory burst, because NADPH oxidase is electrogenic and voltage sensitive. We investigated the recent suggestion that large-conductance, calcium-activated K+ (BK) channels, rather than proton channels, play an essential role in innate immunity (Ahluwalia, J., A. Tinker, L.H. Clapp, M.R. Duchen, A.Y. Abramov, S. Page, M. Nobles, and A.W. Segal. 2004. Nature. 427:853-858). In PMA-stimulated human neutrophils or eosinophils, we did not detect BK currents, and neither of the BK channel inhibitors iberiotoxin or paxilline nor DPI inhibited any component of outward current. BK inhibitors did not inhibit the killing of bacteria, nor did they affect NADPH oxidase-dependent degradation of bacterial phospholipids by extracellular gIIA-PLA2 or the production of superoxide anion (O2.-). Moreover, an antibody against the BK channel did not detect immunoreactive protein in human neutrophils. A required role for voltage-gated proton channels is demonstrated by Zn 2+ inhibition of NADPH oxidase activity assessed by H 2O2 production, thus validating previous studies showing that Zn2+ inhibited O2.- production when assessed by cytochrome c reduction. In conclusion, BK channels were not detected in human neutrophils or eosinophils, and BK inhibitors did not impair antimicrobial activity. In contrast, we present additional evidence that voltage-gated proton channels serve the essential role of charge compensation during the respiratory burst.
AB - Electrophysiological events are of central importance during the phagocyte respiratory burst, because NADPH oxidase is electrogenic and voltage sensitive. We investigated the recent suggestion that large-conductance, calcium-activated K+ (BK) channels, rather than proton channels, play an essential role in innate immunity (Ahluwalia, J., A. Tinker, L.H. Clapp, M.R. Duchen, A.Y. Abramov, S. Page, M. Nobles, and A.W. Segal. 2004. Nature. 427:853-858). In PMA-stimulated human neutrophils or eosinophils, we did not detect BK currents, and neither of the BK channel inhibitors iberiotoxin or paxilline nor DPI inhibited any component of outward current. BK inhibitors did not inhibit the killing of bacteria, nor did they affect NADPH oxidase-dependent degradation of bacterial phospholipids by extracellular gIIA-PLA2 or the production of superoxide anion (O2.-). Moreover, an antibody against the BK channel did not detect immunoreactive protein in human neutrophils. A required role for voltage-gated proton channels is demonstrated by Zn 2+ inhibition of NADPH oxidase activity assessed by H 2O2 production, thus validating previous studies showing that Zn2+ inhibited O2.- production when assessed by cytochrome c reduction. In conclusion, BK channels were not detected in human neutrophils or eosinophils, and BK inhibitors did not impair antimicrobial activity. In contrast, we present additional evidence that voltage-gated proton channels serve the essential role of charge compensation during the respiratory burst.
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U2 - 10.1085/jgp.200609504
DO - 10.1085/jgp.200609504
M3 - Article
C2 - 16702353
AN - SCOPUS:33744491525
SN - 0022-1295
VL - 127
SP - 659
EP - 672
JO - Journal of General Physiology
JF - Journal of General Physiology
IS - 6
ER -