Nucleotide-regulated calcium signaling in lung fibroblasts and epithelial cells from normal and P2Y(2) receptor (-/-) mice.
To test for the role of the P2Y(2) receptor (P2Y(2)-R) in the regulation of nucleotide-promoted Ca(2+) signaling in the lung, we generated P2Y(2)-R-deficient (P2Y(2)-R(-/-)) mice and measured intracellular Ca(2+)(i) responses (DeltaCa(2+)(i)) to nucleotides in cultured lung fibroblasts and nasal and tracheal epithelial cells from wild type and P2Y(2)-R(-/-) mice. In the wild type fibroblasts, the rank order of potencies for nucleotide-induced DeltaCa(2+)(i) was as follows: UTP >/= ATP >> ADP > UDP. The responses induced by these agonists were completely absent in the P2Y(2)-R(-/-) fibroblasts. Inositol phosphate responses paralleled those of DeltaCa(2+)(i) in both groups. ATP and UTP also induced Ca(2+)(i) responses in wild type airway epithelial cells. In the P2Y(2)-R(-/-) airway epithelial cells, UTP was ineffective. A small fraction (25%) of the ATP response persisted. Adenosine and alpha,beta-methylene ATP were ineffective, and ATP responses were not affected by adenosine deaminase or by removal of extracellular Ca(2+), indicating that neither P1 nor P2X receptors mediated this residual ATP response. In contrast, 2-methylthio-ADP promoted a substantial Ca(2+)(i) response in P2Y(2)-R(-/-) cells, which was inhibited by the P2Y(1) receptor antagonist adenosine 3'-5'-diphosphate. These studies demonstrate that P2Y(2)-R is the dominant purinoceptor in airway epithelial cells, which also express a P2Y(1) receptor, and that the P2Y(2)-R is the sole purinergic receptor subtype mediating nucleotide-induced inositol lipid hydrolysis and Ca(2+) mobilization in mouse lung fibroblasts.
Homolya
L
L
Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Watt
W C
WC
Lazarowski
E R
ER
Koller
B H
BH
Boucher
R C
RC
D000818:Animals; D020013:Calcium Signaling; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005704:Gallbladder / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009711:Nucleotides / Q000494:pharmacology*; D018048:Receptors, Purinergic P2 / Q000235:genetics*; D058473:Receptors, Purinergic P2Y2; D014132:Trachea / Q000378:metabolism
D002712:Chlorides; D009711:Nucleotides; C546386:P2ry2 protein, mouse; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2