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The Pseudomonas aeruginosa exoenzyme Y impairs endothelial cell proliferation and vascular repair following lung injury. Am J Physiol Lung Cell Mol Physiol 2014 May 15;306(10):L915-24

Date

04/08/2014

Pubmed ID

24705722

Pubmed Central ID

PMC4025060

DOI

10.1152/ajplung.00135.2013

Scopus ID

2-s2.0-84900807344 (requires institutional sign-in at Scopus site)   66 Citations

Abstract

Exoenzyme Y (ExoY) is a Pseudomonas aeruginosa toxin that is introduced into host cells through the type 3 secretion system (T3SS). Once inside the host cell cytoplasm, ExoY generates cyclic nucleotides that cause tau phosphorylation and microtubule breakdown. Microtubule breakdown causes interendothelial cell gap formation and tissue edema. Although ExoY transiently induces interendothelial cell gap formation, it remains unclear whether ExoY prevents repair of the endothelial cell barrier. Here, we test the hypothesis that ExoY intoxication impairs recovery of the endothelial cell barrier following gap formation, decreasing migration, proliferation, and lung repair. Pulmonary microvascular endothelial cells (PMVECs) were infected with P. aeruginosa strains for 6 h, including one possessing an active ExoY (PA103 exoUexoT::Tc pUCPexoY; ExoY(+)), one with an inactive ExoY (PA103ΔexoUexoT::Tc pUCPexoY(K81M); ExoY(K81M)), and one that lacks PcrV required for a functional T3SS (ΔPcrV). ExoY(+) induced interendothelial cell gaps, whereas ExoY(K81M) and ΔPcrV did not promote gap formation. Following gap formation, bacteria were removed and endothelial cell repair was examined. PMVECs were unable to repair gaps even 3-5 days after infection. Serum-stimulated growth was greatly diminished following ExoY intoxication. Intratracheal inoculation of ExoY(+) and ExoY(K81M) caused severe pneumonia and acute lung injury. However, whereas the pulmonary endothelial cell barrier was functionally improved 1 wk following ExoY(K81M) infection, pulmonary endothelium was unable to restrict the hyperpermeability response to elevated hydrostatic pressure following ExoY(+) infection. In conclusion, ExoY is an edema factor that chronically impairs endothelial cell barrier integrity following lung injury.

Author List

Stevens TC, Ochoa CD, Morrow KA, Robson MJ, Prasain N, Zhou C, Alvarez DF, Frank DW, Balczon R, Stevens T

Author

Dara W. Frank PhD Professor in the Microbiology and Immunology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Bacterial Proteins
Cell Proliferation
Cyclic AMP
Edema
Endothelial Cells
Glucosyltransferases
Host-Pathogen Interactions
Lung
Lung Injury
Male
Microvessels
Pneumonia, Bacterial
Pseudomonas Infections
Pseudomonas aeruginosa
Rats