Regulation of human airway ciliary beat frequency by intracellular pH

Zoltan Sutto, Gregory E. Conner, Matthias Salathe

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)519-532
Number of pages14
JournalJournal of Physiology
Volume560
Issue number2
DOIs
StatePublished - Oct 15 2004

ASJC Scopus subject areas

  • Physiology

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