RhoA/Rho-associated kinase pathway selectively regulates thrombin-induced intercellular adhesion molecule-1 expression in endothelial cells via activation of I kappa B kinase beta and phosphorylation of RelA/p65

J Immunol. 2004 Dec 1;173(11):6965-72. doi: 10.4049/jimmunol.173.11.6965.

Abstract

We investigated the involvement of the RhoA/Rho-associated kinase (ROCK) pathway in regulating ICAM-1 expression in endothelial cells by the procoagulant, thrombin. Exposure of HUVECs to C3 exoenzyme, a selective inhibitor of Rho, markedly reduced thrombin-induced ICAM-1 expression. Inhibition of ROCK, the downstream effector of Rho, also prevented thrombin-induced ICAM-1 expression. Blockade of thrombin-induced ICAM-1 expression was secondary to inhibition of NF-kappaB activity, the key regulator of ICAM-1 expression in endothelial cells. In parallel studies we observed that inhibition of the RhoA/ROCK pathway by the same pharmacological and genetic approaches failed to inhibit TNF-alpha-induced NF-kappaB activation and ICAM-1 expression. The effect of RhoA/ROCK inhibition on thrombin-induced NF-kappaB activation was secondary to inhibition of IkappaB kinase activation and subsequent IkappaBalpha degradation and nuclear uptake and the DNA binding of NF-kappaB. Inhibition of the RhoA/ROCK pathway also prevented phosphorylation of Ser(536) within the transactivation domain 1 of NF-kappaB p65/RelA, a critical event conferring transcriptional competency to the bound NF-kappaB. Thus, the RhoA/ROCK pathway signals thrombin-induced ICAM-1 expression through the activation of IkappaB kinase, which promotes NF-kappaB binding to ICAM-1 promoter and phosphorylation of RelA/p65, thus mediating the transcriptional activation of bound NF-kappaB.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Line
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / enzymology*
  • Endothelium, Vascular / metabolism
  • Enzyme Activation
  • Humans
  • I-kappa B Kinase
  • Intercellular Adhesion Molecule-1 / biosynthesis
  • Intercellular Adhesion Molecule-1 / genetics
  • Intercellular Adhesion Molecule-1 / physiology*
  • Intracellular Signaling Peptides and Proteins
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Protein-Serine-Threonine Kinases / metabolism*
  • Protein-Serine-Threonine Kinases / physiology*
  • RNA, Messenger / antagonists & inhibitors
  • RNA, Messenger / biosynthesis
  • Signal Transduction / physiology*
  • Thrombin / antagonists & inhibitors
  • Thrombin / physiology*
  • Transcription Factor RelA
  • rho-Associated Kinases
  • rhoA GTP-Binding Protein / antagonists & inhibitors
  • rhoA GTP-Binding Protein / physiology*

Substances

  • Intracellular Signaling Peptides and Proteins
  • NF-kappa B
  • RNA, Messenger
  • Transcription Factor RelA
  • Intercellular Adhesion Molecule-1
  • Protein-Serine-Threonine Kinases
  • rho-Associated Kinases
  • CHUK protein, human
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human
  • Thrombin
  • rhoA GTP-Binding Protein