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Pulmonary Endothelial Barrier Disruption via Bicarbonate Stimulation of Endogenous Soluble Adenylyl Cyclase, AC10
Author(s) -
Sayner Sarah,
Kunstadt Ryan,
Nix Jessica
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1130.3
Subject(s) - bicarbonate , cytosol , endothelial stem cell , phosphorylation , adenylyl cyclase , phosphodiesterase , microbiology and biotechnology , chemistry , stimulation , biology , biochemistry , signal transduction , enzyme , endocrinology , in vitro
Transmembrane adenylyl cyclase (AC) generates subplasma membrane cAMP that strengthens the pulmonary endothelial barrier. In contrast, P. aeruginosa inserts the toxic soluble AC, ExoY, into pulmonary microvascular endothelial cells (PMVECs) where it generates cytosolic cAMP that phosphorylates the microtubule associating protein, tau, destabilizes microtubules and disrupts the endothelial barrier. A mammalian soluble AC, AC10, has been identified, which also localizes to the cytosol. We tested the hypothesis that bicarbonate stimulation of AC10 increases pulmonary endothelial cell permeability via tau phosphorylation. Western analysis revealed PMVECs have greater AC10 expression than pulmonary artery endothelial cells (PAECs). While adjusting CO 2 tension to maintain constant media pH, bicarbonate dose‐dependently increased the phosphodiesterase 4 sensitive cAMP pool in PMVECs, but not in PAECs. RT‐PCR and Western analysis revealed heterogeneous expression of carbonic anhydrase and bicarbonate cotransporters in pulmonary endothelial cells. Further, bicarbonate increased tau serine214 phosphorylation and decreased resistance across the PMVEC monolayer. These data reveal bicarbonate stimulates AC10 activity generating a phosphodiesterase 4 regulated cAMP pool in PMVECs, which increases tau phosphorylation and compromises PMVEC barrier integrity. Funding AHA11GRNT7430039