Differential role of Rho GTPases in endothelial barrier regulation dependent on endothelial cell origin

Histochem Cell Biol. 2008 Feb;129(2):179-91. doi: 10.1007/s00418-007-0358-7. Epub 2007 Nov 21.


From studies using macrovascular endothelium, it was concluded that Rho A activation generally leads to endothelial barrier breakdown. Here, we characterized the role of Rho GTPases in endothelial barrier regulation in four different cell lines, both microvascular and macrovascular. Rho A activation by cytotoxic necrotizing factor y (CNFy) induced stress fiber formation in all cell lines. This was paralleled by gap formation and barrier breakdown in microvascular mesenteric endothelial cells (MesEnd), human dermal microvascular endothelial cells (HDMEC) as well as in macrovascular pulmonary artery endothelial cells (PAEC) but not in microvascular myocardial endothelial cells (MyEnd). In MyEnd cells, activation of Rac 1 and Cdc42 by CNF-1 strengthened barrier properties whereas in MesEnd, HDMEC and PAEC all three GTPases were activated which increased permeability in PAEC but not in MesEnd and HDMEC. In PAEC, CNF-1-induced decrease of barrier properties was blocked by the Rho kinase inhibitor Y27632 indicating that co-activation of Rho A dominated the barrier response. Inactivation of Rac 1 by toxin B or by lethal toxin (LT) compromised barrier properties in all cell lines. Taken together, Rac 1 requirement for endothelial barrier maintenance but not the destabilizing role of Rho A seems to be ubiquitous.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amides / pharmacology
  • Animals
  • Bacterial Toxins / pharmacology
  • Capillary Permeability / drug effects
  • Capillary Permeability / physiology*
  • Cell Line
  • Cells, Cultured
  • Endothelial Cells / drug effects
  • Endothelial Cells / physiology*
  • Enzyme Inhibitors / pharmacology
  • Escherichia coli Proteins / pharmacology
  • Humans
  • Mice
  • Pyridines / pharmacology
  • Swine
  • cdc42 GTP-Binding Protein / physiology
  • rac1 GTP-Binding Protein / drug effects
  • rac1 GTP-Binding Protein / physiology
  • rho GTP-Binding Proteins / drug effects
  • rho GTP-Binding Proteins / physiology*
  • rhoA GTP-Binding Protein / antagonists & inhibitors
  • rhoA GTP-Binding Protein / physiology*


  • Amides
  • Bacterial Toxins
  • Enzyme Inhibitors
  • Escherichia coli Proteins
  • Pyridines
  • cytotoxic necrotizing factor type 1
  • Y 27632
  • cdc42 GTP-Binding Protein
  • rac1 GTP-Binding Protein
  • rho GTP-Binding Proteins
  • rhoA GTP-Binding Protein