Protein kinase C-α and arginase I mediate pneumolysin-induced pulmonary endothelial hyperpermeability

Rudolf Lucas, Guang Yang, Boris A Gorshkov, Evgeny Alexandrovich Zemskov, Supriya Sridhar, Umapathy N Siddaramappa, Agnieszka Jezierska-Drutel, Irina B. Alieva, Martin Leustik, Hamid Hossain, Bernhard Fischer, John D. Catravas, Alexander Dmitriyevich Verin, Jean François Pittet, Ruth B Caldwell, Timothy J. Mitchell, Stephen D. Cederbaum, David J Fulton, Michael A. Matthay, Robert William CaldwellMaritza Josefina Romero Lucas, Trinad Chakraborty

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Antibiotics-induced release of the pore-forming virulence factor pneumolysin (PLY) in patients with pneumococcal pneumonia results in its presence days after lungs are sterile and is a major factor responsible for the induction of permeability edema. Here we sought to identify major mechanisms mediating PLY-induced endothelial dysfunction. We evaluated PLY-induced endothelial hyperpermeability in human lung microvascular endothelial cells (HL-MVECs) and human lung pulmonary artery endothelial cells in vitro and in mice instilled intratracheally with PLY. PLY increases permeability in endothelial monolayers by reducing stable and dynamic microtubule content and modulating VE-cadherin expression. These events, dependent upon an increased calcium influx, are preceded by protein kinase C (PKC)-α activation, perturbation of the RhoA/Rac1 balance, and an increase in myosin light chain phosphorylation. At later time points, PLY treatment increases the expression and activity of arginase in HL-MVECs. Arginase inhibition abrogates and suppresses PLY-induced endothelial barrier dysfunction by restoring NO generation. Consequently, a specific PKC-α inhibitor and the TNF-derived tonoplast intrinsic protein peptide, which blunts PLY-induced PKC-α activation, are able to prevent activation of arginase in HL-MVECs and to reduce PLY-induced endothelial hyperpermeability in mice. Arginase I (AI) +/-/arginase II (AII)-/- C57BL/6 mice, displaying a significantly reduced arginase I expression in the lungs, are significantly less sensitive to PLY-induced capillary leak than their wild-type or AI +/+/AII-/- counterparts, indicating an important role for arginase I in PLY-induced endothelial hyperpermeability. These results identify PKC-α and arginase I as potential upstream and downstream therapeutic targets in PLY-induced pulmonary endothelial dysfunction.

Original languageEnglish (US)
Pages (from-to)445-453
Number of pages9
JournalAmerican journal of respiratory cell and molecular biology
Volume47
Issue number4
DOIs
StatePublished - Oct 2012

Keywords

  • Arginase
  • PKC
  • Pneumococcus
  • Pneumolysin
  • TNF

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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