TY - JOUR
T1 - Regulation of human airway ciliary beat frequency by intracellular pH
AU - Sutto, Zoltan
AU - Conner, Gregory E.
AU - Salathe, Matthias
PY - 2004/10/15
Y1 - 2004/10/15
N2 - pHi affects a number of cellular functions, but the influence of pHi on mammalian ciliary beat frequency (CBF) is not known. CBF and pHi of single human tracheobronchial epithelial cells in submerged culture were measured simultaneously using video microscopy (for CBF) and epifluorescence microscopy with the pH-sensitive dye BCECF. Baseline CBF and pHi values in bicarbonate-free medium were 7.2 ± 0.2 Hz and 7.49 ± 0.02, respectively (n = 63). Alkalization by ammonium pre-pulse to pHi 7.78 ± 0.02 resulted in a 2.2 ± 0.1 Hz CBF increase (P < 0.05). Following removal of NH4Cl, pHi decreased to 7.24 ± 0.02 and CBF to 5.8 ± 0.1 Hz (P < 0.05). Removal of extracellular CO2 to change pHi resulted in similar CBF changes. Pre-activation of cAMP-dependent protein kinase (10 μM forskolin), broad inhibition of protein kinases (100 μM H-7), inhibition of PKA (10 μM H-89), nor inhibition of phosphatases (10 μM cyclosporin + 1.5 μM okadaic acid) changed pHi-mediated changes in CBF, nor were they due to [Ca2+]i changes. CBF of basolaterally permeabilized human trachcobronchial cells, re-differentiated at the air-liquid interface, was 3.9 ± 0.3, 5.7 ± 0.4, 7.0 ± 0.3 and 7.3 ± 0.3 Hz at basolateral i.e., intracellular pH of 6.8, 7.2, 7.6 and 8.0, respectively (n = 18). Thus, intracellular alkalization stimulates, while intracellular acidification attenuates human airway CBF. Since phosphorylation and [Ca2+]i changes did not seem to mediate pHi-induced CBF changes, pHi may directly act on the ciliary motile machinery.
AB - pHi affects a number of cellular functions, but the influence of pHi on mammalian ciliary beat frequency (CBF) is not known. CBF and pHi of single human tracheobronchial epithelial cells in submerged culture were measured simultaneously using video microscopy (for CBF) and epifluorescence microscopy with the pH-sensitive dye BCECF. Baseline CBF and pHi values in bicarbonate-free medium were 7.2 ± 0.2 Hz and 7.49 ± 0.02, respectively (n = 63). Alkalization by ammonium pre-pulse to pHi 7.78 ± 0.02 resulted in a 2.2 ± 0.1 Hz CBF increase (P < 0.05). Following removal of NH4Cl, pHi decreased to 7.24 ± 0.02 and CBF to 5.8 ± 0.1 Hz (P < 0.05). Removal of extracellular CO2 to change pHi resulted in similar CBF changes. Pre-activation of cAMP-dependent protein kinase (10 μM forskolin), broad inhibition of protein kinases (100 μM H-7), inhibition of PKA (10 μM H-89), nor inhibition of phosphatases (10 μM cyclosporin + 1.5 μM okadaic acid) changed pHi-mediated changes in CBF, nor were they due to [Ca2+]i changes. CBF of basolaterally permeabilized human trachcobronchial cells, re-differentiated at the air-liquid interface, was 3.9 ± 0.3, 5.7 ± 0.4, 7.0 ± 0.3 and 7.3 ± 0.3 Hz at basolateral i.e., intracellular pH of 6.8, 7.2, 7.6 and 8.0, respectively (n = 18). Thus, intracellular alkalization stimulates, while intracellular acidification attenuates human airway CBF. Since phosphorylation and [Ca2+]i changes did not seem to mediate pHi-induced CBF changes, pHi may directly act on the ciliary motile machinery.
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U2 - 10.1113/jphysiol.2004.068171
DO - 10.1113/jphysiol.2004.068171
M3 - Article
C2 - 15308676
AN - SCOPUS:7444247352
VL - 560
SP - 519
EP - 532
JO - Journal of Physiology
JF - Journal of Physiology
SN - 0022-3751
IS - 2
ER -