title: Paradoxical cAMP-induced lung endothelial hyperpermeability revealed by Pseudomonas aeruginosa ExoY.
abstract: Mammalian transmembrane adenylyl cyclases synthesize a restricted plasmalemmal cAMP pool that is intensely endothelial barrier protective. Bacteria have devised mechanisms of transferring eukaryotic factor-dependent adenylyl cyclases into mammalian cells. Pseudomonas aeruginosa ExoY is one such enzyme that catalyzes cytosolic cAMP synthesis, with unknown function. Pseudomonas aeruginosa genetically modified to introduce only the ExoY toxin elevated cAMP 800-fold in pulmonary microvascular endothelial cells over 4 hours, whereas a catalytically deficient (ExoY(K81M)) strain did not increase cAMP. ExoY-derived cAMP was localized to a cytosolic microdomain not regulated by phosphodiesterase activity. In contrast to the barrier-enhancing actions of plasmalemmal cAMP, the ExoY cytosolic cAMP pool induced endothelial gap formation and increased the filtration coefficient in the isolated perfused lung. These findings collectively illustrate a previously unrecognized mechanism of hyperpermeability induced by rises in cytosolic cAMP.
authors.affiliation: Center for Lung Biology, University of South Alabama, College of Medicine, Mobile, AL 36688, USA.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Sayner
authors.forename: Dara W
authors.initials: DW
authors.lastname: Frank
authors.forename: Judy
authors.initials: J
authors.lastname: King
authors.forename: Hairu
authors.initials: H
authors.lastname: Chen
authors.forename: John
authors.initials: J
authors.lastname: VandeWaa
authors.forename: Troy
authors.initials: T
authors.lastname: Stevens
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000502:physiology; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000032:analysis / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002196:Capillaries / Q000166:cytology; D002384:Catalysis; D002451:Cell Compartmentation; D002463:Cell Membrane Permeability; D002478:Cells, Cultured / Q000378:metabolism / Q000382:microbiology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis / Q000502:physiology*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D003600:Cytosol / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism / Q000382:microbiology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism / Q000382:microbiology; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D007365:Intercellular Junctions / Q000187:drug effects; D008168:Lung / Q000098:blood supply*; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020889:Rolipram / Q000494:pharmacology; D015290:Second Messenger Systems / Q000187:drug effects / Q000502:physiology*; D013329:Structure-Activity Relationship
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D001426:Bacterial Proteins; D010726:Phosphodiesterase Inhibitors; D005576:Colforsin; D000242:Cyclic AMP; C111504:ExoY protein, bacteria; D005964:Glucosyltransferases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D000262:Adenylyl Cyclases; D020889:Rolipram