The Pseudomonas aeruginosa exoenzyme Y impairs endothelial cell proliferation and vascular repair following lung injury

Trevor C. Stevens, Cristhiaan D. Ochoa, K. Adam Morrow, Matthew J. Robson, Nutan Prasain, Chun Zhou, Diego F. Alvarez, Dara W. Frank, Ron Balczon, Troy Stevens

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


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 pUCPexoYK81M; ExoYK81M, and one that lacks PcrV required for a functional T3SS (ΔPcrV. ExoY+ induced interendothelial cell gaps, whereas ExoYK81M 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 ExoYK81M caused severe pneumonia and acute lung injury. However, whereas the pulmonary endothelial cell barrier was functionally improved 1 wk following ExoYK81Minfection, 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.

Original languageEnglish (US)
Pages (from-to)L915-L924
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number10
StatePublished - 2014
Externally publishedYes


  • Cyclase
  • Microtubules
  • Permeability
  • Pulmonary edema
  • Tau

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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