Premium
Prolonged increase in ciliary beat frequency after short‐term purinergic stimulation in human airway epithelial cells
Author(s) -
Lieb Thomas,
Frei Corinne Wijkstrom,
Frohock Jeffrey I.,
Bookman Richard J.,
Salathe Matthias
Publication year - 2002
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2001.013222
Subject(s) - medicine , endocrinology , forskolin , purinergic receptor , stimulation , calcium , adenylyl cyclase , thapsigargin , protein kinase c , chemistry , adenosine , biology , kinase , biochemistry
Stimulation of ovine airway epithelial cells with 10 μ m 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 μ m myristoylated PKA‐inhibitory peptide and 1 μ m KT‐5720, as well as an inhibitor of adenylyl cyclase, 1 m m 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 μ m 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 μ m ), 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 μ m thapsigargin. These data suggest that in human, but not ovine airway epithelial 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.