title: Dominant regulation of interendothelial cell gap formation by calcium-inhibited type 6 adenylyl cyclase.
abstract: Acute transitions in cytosolic calcium ([Ca2+]i) through store-operated calcium entry channels catalyze interendothelial cell gap formation that increases permeability. However, the rise in [Ca2+]i only disrupts barrier function in the absence of a rise in cAMP. Discovery that type 6 adenylyl cyclase (AC6; EC 4.6.6.1) is inhibited by calcium entry through store-operated calcium entry pathways provided a plausible explanation for how inflammatory [Ca2+]i mediators may decrease cAMP necessary for endothelial cell gap formation. [Ca2+]i mediators only modestly decrease global cAMP concentrations and thus, to date, the physiological role of AC6 is unresolved. Present studies used an adenoviral construct that expresses the calcium-stimulated AC8 to convert normal calcium inhibition into stimulation of cAMP, within physiologically relevant concentration ranges. Thrombin stimulated a dose-dependent [Ca2+]i rise in both pulmonary artery (PAECs) and microvascular (PMVEC) endothelial cells, and promoted intercellular gap formation in both cell types. In PAECs, gap formation was progressive over 2 h, whereas in PMVECs, gap formation was rapid (within 10 min) and gaps resealed within 2 h. Expression of AC8 resulted in a modest calcium stimulation of cAMP, which virtually abolished thrombin-induced gap formation in PMVECs. Findings provide the first direct evidence that calcium inhibition of AC6 is essential for endothelial gap formation.
authors.affiliation: Department of Pharmacology, University of South Alabama College of Medicine, Mobile, AL 36688, USA.
authors.forename: Donna L
authors.initials: DL
authors.lastname: Cioffi
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Moore
authors.forename: Jerry
authors.initials: J
authors.lastname: Schaack
authors.forename: Judy R
authors.initials: JR
authors.lastname: Creighton
authors.forename: Dermot M F
authors.initials: DM
authors.lastname: Cooper
authors.forename: Troy
authors.initials: T
authors.lastname: Stevens
mesh_terms: D000256:Adenoviridae; D000262:Adenylyl Cyclases / Q000378:metabolism* / Q000502:physiology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002450:Cell Communication; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D003600:Cytosol / Q000737:chemistry; D004727:Endothelium / Q000166:cytology* / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005786:Gene Expression Regulation / Q000235:genetics*; D006490:Hemostatics / Q000494:pharmacology; D008168:Lung / Q000098:blood supply; D011651:Pulmonary Artery / Q000166:cytology; D015398:Signal Transduction / Q000187:drug effects; D013917:Thrombin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D006490:Hemostatics; D000242:Cyclic AMP; D013917:Thrombin; D000262:Adenylyl Cyclases; C121100:adenylyl cyclase 6; C118292:adenylyl cyclase 8; D002118:Calcium