Differential effect of MLC kinase in TNF-α-induced endothelial cell apoptosis and barrier dysfunction

Irina Petrache, Alexander D. Verin, Michael T. Crow, Anna Birukova, Feng Liu, Joe G.N. Garcia

Research output: Contribution to journalArticlepeer-review

190 Scopus citations


Tumor necrosis factor (TNF)-α is released in acute inflammatory lung syndromes linked to the extensive vascular dysfunction associated with increased permeability and endothelial cell apoptosis. TNF-α induced significant decreases in transcellular electrical resistance across pulmonary endothelial cell monolayers, reflecting vascular barrier dysfunction (beginning at 4 h and persisting for 48 h). TNF-α also triggered endothelial cell apoptosis beginning at 4 h, which was attenuated by the caspase inhibitor Z-Val-Ala-Asp-fluoromethyl-ketone. Exploring the involvement of the actomyosin cytoskeleton in these important endothelial cell responses, we determined that TNF-α significantly increased myosin light chain (MLC) phosphorylation, with prominent stress fiber and paracellular gap formation, which paralleled the onset of decreases in transcellular electrical resistance and enhanced apoptosis. Reductions in MLC phosphorylation by the inhibition of either MLC kinase (ML-7, cholera toxin) or Rho kinase (Y-27632) dramatically attenuated TNF-α-induced stress fiber formation, indexes of apoptosis, and caspase-8 activity but not TNF-α-induced barrier dysfunction. These studies indicate a central role for the endothelial cell cytoskeleton in TNF-α-mediated apoptosis, whereas TNF-α-induced vascular permeability appears to evolve independently of contractile tension generation.

Original languageEnglish (US)
Pages (from-to)L1168-L1178
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number6 24-6
StatePublished - 2001
Externally publishedYes


  • Acute lung injury
  • Caspases
  • Cytoskeleton
  • Permeability
  • Rho kinase
  • Tumor necrosis factor-α

ASJC Scopus subject areas

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


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