Rapid and non-genomic reduction of intracellular [Ca(2+)] induced by aldosterone in human bronchial epithelium.
1. Using a Ca(2+) imaging system and fura-2 AM (5 microM) we showed that exposure of polarised monolayers of human bronchial epithelial cells (16HBE14o- cell line) to aldosterone produced a fast intracellular [Ca(2+)] ([Ca(2+)](i)) decrease, in 70 % of cells. Exposure to aldosterone (1 nM) reduced the [Ca(2+)](i) by 39 +/- 9 nM (n = 282, P < 0.0001) within 10 min, from a basal [Ca(2+)](i) of 131 +/- 19 nM (n = 282). 2. The effect of aldosterone on [Ca(2+)](i) was not affected by inhibitors of the classical genomic pathway, cycloheximide (1 microM) or spironolactone (10 microM). The aldosterone-induced [Ca(2+)](i) decrease was inhibited by thapsigargin (1 microM), pertussis toxin (24 h at 200 ng ml(-1)), the adenylate cyclase inhibitors 2',3'-dideoxyadenosine (200 microM) and MDL-12,330A hydrochloride (500 microM), and the protein kinase A inhibitor R(P)-adenosine 3',5'-cyclic monophosphorothioate (200 microM). In addition, treatment of 16HBE14o- monolayers with aldosterone (1 nM) inhibited by approximately 30 % the large and transient [Ca(2+)](i) increase induced by apical exposure to uridine triphosphate (UTP, 0.1 mM), a known secretagogue in airway epithelia. 3. Our results demonstrate for the first time that in human bronchial epithelial cells, aldosterone decreases [Ca(2+)](i) levels via a non-genomic mechanism. The hormone-induced changes to [Ca(2+)](i) involve stimulation of thapsigargin-sensitive Ca(2+)-ATPase, via G-protein-, adenylate cyclase- and protein kinase A-coupled signalling pathways.
Urbach
V
V
INSERM U454, CHU Arnaud de Villeneuve, 34295 Montpellier, France. urbach@montp.inserm.fr
Harvey
B J
BJ
D000262:Adenylyl Cyclases / Q000502:physiology; D000450:Aldosterone / Q000494:pharmacology*; D001980:Bronchi / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002461:Cell Line, Transformed; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D003513:Cycloheximide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D000451:Mineralocorticoid Receptor Antagonists / Q000494:pharmacology; D009994:Osmolar Concentration; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013148:Spironolactone / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors; D014544:Uridine Triphosphate / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology
D004791:Enzyme Inhibitors; D005938:Glucocorticoids; D000451:Mineralocorticoid Receptor Antagonists; D011500:Protein Synthesis Inhibitors; D013148:Spironolactone; D014638:Vanadates; D000450:Aldosterone; D019284:Thapsigargin; D003513:Cycloheximide; D012964:Sodium; D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D002118:Calcium; D014544:Uridine Triphosphate