title: A(2) adenosine receptors regulate CFTR through PKA and PLA(2).
abstract: We investigated adenosine (Ado) activation of the cystic fibrosis transmembrane conductance regulator (CFTR) in vitro and in vivo. A(2B) Ado receptors were identified in Calu-3, IB-3-1, COS-7, and primary human airway cells. Ado elevated cAMP in Calu-3, IB-3-1, and COS-7 cells and activated protein kinase A-dependent halide efflux in Calu-3 cells. Ado promoted arachidonic acid release from Calu-3 cells, and phospholipase A(2) (PLA(2)) inhibition blocked Ado-activated halide efflux in Calu-3 and COS-7 cells expressing CFTR. Forskolin- and beta(2)-adrenergic receptor-stimulated efflux were not affected by the same treatment. Cytoplasmic PLA(2) (cPLA(2)) was identified in Calu-3, IB-3-1, and COS-7 cells, but cPLA(2) inhibition did not affect Ado-stimulated cAMP concentrations. In cftr(+) and cftr(-/-) mice, Ado stimulated nasal Cl(-) secretion that was CFTR dependent and sensitive to A(2) receptor and PLA(2) blockade. In COS-7 cells transiently expressing DeltaF508 CFTR, Ado activated halide efflux. Ado also activated G551D CFTR-dependent halide efflux when combined with arachidonic acid and phosphodiesterase inhibition. In conclusion, PLA(2) and protein kinase A both contribute to A(2) receptor activation of CFTR, and components of this signaling pathway can augment wild-type and mutant CFTR activity.
authors.affiliation: Department of Human Genetics, University of Alabama at Birmingham, 35233, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Cobb
authors.forename: F
authors.initials: F
authors.lastname: Ruiz
authors.forename: C M
authors.initials: CM
authors.lastname: King
authors.forename: J
authors.initials: J
authors.lastname: Fortenberry
authors.forename: H
authors.initials: H
authors.lastname: Greer
authors.forename: T
authors.initials: T
authors.lastname: Kovacs
authors.forename: E J
authors.initials: EJ
authors.lastname: Sorscher
authors.forename: J P
authors.initials: JP
authors.lastname: Clancy
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D019556:COS Cells; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D051379:Mice; D010741:Phospholipases A / Q000502:physiology*; D020033:Protein Isoforms / Q000502:physiology; D018047:Receptors, Purinergic P1 / Q000502:physiology*
chemical_list: C505032:CFTR protein, human; D002712:Chlorides; D020033:Protein Isoforms; D018047:Receptors, Purinergic P1; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D017868:Cyclic AMP-Dependent Protein Kinases; D010741:Phospholipases A; D000262:Adenylyl Cyclases