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This Article Full Text Full Text (PDF) All Versions of this Article: 38/1/42    most recent 00012.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Xue, J. Articles by Tiruppathi, C. PubMed PubMed Citation Articles by Xue, J. Articles by Tiruppathi, C.

NF-B regulates thrombin-induced ICAM-1 gene expression in cooperation with NFAT by binding to the intronic NF-B site in the ICAM-1 gene

¹ Department of Pharmacology, College of Medicine, University of Illinois, Chicago, Illinois
² Department of Medicine, Section of Pulmonary, Critical Care and Sleep Medicine, College of Medicine, University of Illinois, Chicago, Illinois
³ Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois

Activation of NF-B is essential for protease-activated receptor-1 (PAR-1)-mediated ICAM-1 expression in endothelial cells. Here we show that PAR-1 activation induces binding of both p65/RelA and NFATc1 to the NF-B binding site localized in intron-1 of the ICAM-1 gene to initiate transcription in endothelial cells. We discovered the presence of two NF-B binding sites in intron-1 (+70, NF-B site 1; +611, NF-B site 2) of the human ICAM-1 gene. Chromatin immunoprecipitation results showed that thrombin induced binding of p65/RelA and of NFATc1 specifically to intronic NF-B site 1 of the ICAM-1 gene. Electrophoretic mobility shift and supershift assays confirmed the binding of p65/RelA and NFATc1 to the intronic NF-B site 1 in thrombin-stimulated cells. Thrombin increased the expression of ICAM-1-promoter-intron 1-reporter (–1,385 to +234) construct 25-fold and mutation of intronic NF-B site 1 markedly reduced thrombin-induced reporter expression. Moreover, inhibition of calcineurin, knockdown of either NFATc1 or p65/RelA with siRNA significantly reduced thrombin-induced ICAM-1 expression and polymorphonuclear leukocyte adhesion to endothelial cells. In contrast, NFATc1 knockdown had no effect on TNF--induced ICAM-1 expression. Thus these results suggest that p65/RelA and NFATc1 bind to the intronic NF-B site 1 sequence to induce optimal transcription of the ICAM-1 gene in response to thrombin in endothelial cells.

endothelial cells; protease-activated receptor-1; tumor necrosis factor-; intercellular adhesion molecule-1; calcineurin; nuclear factor-B; nuclear factor of activated T cells