TY - JOUR
T1 - Prolonged increase in ciliary beat frequency after short-term purinergic stimulation in human airway epithelial cells
AU - Lieb, Thomas
AU - Frei, Corinne Wijkstrom
AU - Frohock, Jeffrey I.
AU - Bookman, Richard J.
AU - Salathe, Matthias
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2002/1/15
Y1 - 2002/1/15
N2 - Stimulation of ovine airway epithelial cells with 10 μM ATP for 1 min at 25 °C transiently increased both cytoplasmic calcium (fura-2 epifluorescence microscopy) and ciliary beat frequency (CBF; differential interference contrast microscopy) with a similar time course. Identical purinergic stimulation of human airway epithelial cells at 25 or 35 °C, however, lead to an increase in CBF that outlasted the calcium transient at least 20 min. While a nitric oxide synthase inhibitor had no effect, pre-treatment of human cells with inhibitors of cAMP-dependent kinase (PKA), 10 μM myristoylated PKA-inhibitory peptide and 1 μM KT-5720, as well as an inhibitor of adenylyl cyclase, 1 mM SQ22536, blocked the prolonged, but not calcium-coupled CBF increase. Addition of PKA inhibitors after purinergic stimulation only partially reduced CBF from its elevated plateau. Prolonged CBF increases did not depend on adenosine production as 10 μM UTP had an effect similar to ATP and 8-sulphophenyl-theophylline did not block them. After increasing human CBF in a PKA-dependent manner to a stable plateau with forskolin (10 μM), ATP caused only a transient, calcium-coupled CBF increase. Calcium transients were necessary for both short-term and prolonged CBF changes as ATP failed to produce CBF increases after emptying calcium stores with 1 μM thapsigargin. These data suggest that in human, but not ovine airway epithelia] cells, ATP-induced calcium transients activate a signalling cascade including adenylyl cyclase and PKA. The resulting prolonged CBF stimulation does not rely only on PKA activity, suggesting that the decay of CBF is influenced by ciliary phosphatase activity.
AB - Stimulation of ovine airway epithelial cells with 10 μM ATP for 1 min at 25 °C transiently increased both cytoplasmic calcium (fura-2 epifluorescence microscopy) and ciliary beat frequency (CBF; differential interference contrast microscopy) with a similar time course. Identical purinergic stimulation of human airway epithelial cells at 25 or 35 °C, however, lead to an increase in CBF that outlasted the calcium transient at least 20 min. While a nitric oxide synthase inhibitor had no effect, pre-treatment of human cells with inhibitors of cAMP-dependent kinase (PKA), 10 μM myristoylated PKA-inhibitory peptide and 1 μM KT-5720, as well as an inhibitor of adenylyl cyclase, 1 mM SQ22536, blocked the prolonged, but not calcium-coupled CBF increase. Addition of PKA inhibitors after purinergic stimulation only partially reduced CBF from its elevated plateau. Prolonged CBF increases did not depend on adenosine production as 10 μM UTP had an effect similar to ATP and 8-sulphophenyl-theophylline did not block them. After increasing human CBF in a PKA-dependent manner to a stable plateau with forskolin (10 μM), ATP caused only a transient, calcium-coupled CBF increase. Calcium transients were necessary for both short-term and prolonged CBF changes as ATP failed to produce CBF increases after emptying calcium stores with 1 μM thapsigargin. These data suggest that in human, but not ovine airway epithelia] cells, ATP-induced calcium transients activate a signalling cascade including adenylyl cyclase and PKA. The resulting prolonged CBF stimulation does not rely only on PKA activity, suggesting that the decay of CBF is influenced by ciliary phosphatase activity.
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U2 - 10.1113/jphysiol.2001.013222
DO - 10.1113/jphysiol.2001.013222
M3 - Article
C2 - 11790825
AN - SCOPUS:0037082217
VL - 538
SP - 633
EP - 646
JO - Journal of Physiology
JF - Journal of Physiology
SN - 0022-3751
IS - 2
ER -