title: Lipoxin A4 stimulates a cytosolic Ca2+ increase in human bronchial epithelium.
abstract: Lipoxins are biologically active eicosanoids possessing anti-inflammatory properties. Using a calcium imaging system we investigated the effect of lipoxin A(4) (LXA(4)) on intracellular [Ca(2+)] ([Ca(2+)](i)) of human bronchial epithelial cell. Exposure of the cells to LXA(4) produced a dose-dependent increase in [Ca(2+)](i) followed by a recovery to basal values in primary culture and in 16HBE14o(-) cells. The LXA(4)-induced [Ca(2+)](i) increase was completely abolished after pre-treatment of the 16HBE14o(-) cells with pertussis toxin (G-protein inhibitor). The [Ca(2+)](i) response was not affected by the removal of external [Ca(2+)] but completely inhibited by thapsigargin (Ca(2+)-ATPase inhibitor) treatment. Pre-treatment of the bronchial epithelial cells with either MDL hydrochloride (adenylate cyclase inhibitor) or (R(p))-cAMP (cAMP-dependent protein kinase inhibitor) inhibited the Ca(2+) response to LXA(4). However, the response was not affected by chelerytrine chloride (protein kinase C inhibitor) or montelukast (cysteinyl leukotriene receptor antagonist). The LXA(4) receptor mRNA was detected, by RT-PCR, in primary culture of human bronchial epithelium and in immortalized 16HBE14o(-) cells. The functional consequences of the effect of LXA(4) on intracellular [Ca(2+)](i) have been investigated on Cl(-) secretion, measured using the short-circuit techniques on 16HBE14o(-) monolayers grown on permeable filters. LXA(4) produced a sustained stimulation of the Cl(-) secretion by 16HBE14o(-) monolayers, which was inhibited by BAPTA-AM, a chelator of intracellular calcium. Taken together our results provided evidence for the stimulation of a [Ca(2+)](i) increase by LXA(4) through a mechanism involving its specific receptor and protein kinase A activation and resulting in a subsequent Ca(2+)-dependent Cl(-) secretion by human airway epithelial cells.
authors.affiliation: INSERM U454, Department of Respiratory Disease, Centre Hospitalier Universitaire Arnaud de Villeneuve, 34295 Montpellier Cedex 05, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Bonnans
authors.forename: Brigitte
authors.initials: B
authors.lastname: Mainprice
authors.forename: Pascal
authors.initials: P
authors.lastname: Chanez
authors.forename: Jean
authors.initials: J
authors.lastname: Bousquet
authors.forename: Valerie
authors.initials: V
authors.lastname: Urbach
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000470:Alkaloids; D001483:Base Sequence; D053119:Benzophenanthridines; D001980:Bronchi / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002461:Cell Line, Transformed; D000242:Cyclic AMP / Q000494:pharmacology; D003521:Cyclopropanes; D003600:Cytosol / Q000378:metabolism*; D017931:DNA Primers; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism / Q000502:physiology*; D007097:Imines / Q000494:pharmacology; D044045:Lipoxins; D037342:Pertussis Toxin / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013440:Sulfides
chemical_list: D000085:Acetates; D000470:Alkaloids; D053119:Benzophenanthridines; D003521:Cyclopropanes; D017931:DNA Primers; C105101:FPR2 protein, human; D006893:Hydroxyeicosatetraenoic Acids; D007097:Imines; D044045:Lipoxins; D010617:Phenanthridines; D011804:Quinolines; D011956:Receptors, Cell Surface; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D013440:Sulfides; C040527:lipoxin A4; C014925:RMI 12330A; D000242:Cyclic AMP; C016299:chelerythrine; D037342:Pertussis Toxin; C093875:montelukast; D002118:Calcium