We addressed the regulatory function of mammalian target of rapamycin (mTOR) in the mechanism of thrombin-induced ICAM-1 gene expression in endothelial cells. Pretreatment of HUVECs with rapamycin, an inhibitor of mTOR, augmented thrombin-induced ICAM-1 expression. Inhibition of mTOR by this approach promoted whereas over-expression of mTOR inhibited thrombin-induced transcriptional activity of NF-κB, an essential regulator of ICAM-1 transcription. Analysis of the NF-κB signaling pathway revealed that inhibition of mTOR potentiated IκB kinase activation resulting in a rapid and persistent phosphorylation of IκBα on Ser32 and Ser36, a requirement for IκBα degradation. Consistent with these data, we observed a more efficient and stable nuclear localization of RelA/p65 and, subsequently, the DNA binding activity of NF-κB by thrombin following mTOR inhibition. These data define a novel role of mTOR in down-regulating thrombin-induced ICAM-1 expression in endothelial cells by controlling a delayed and transient activation of NF-κB.
CITATION STYLE
Minhajuddin, M., Fazal, F., Bijli, K. M., Amin, Md. R., & Rahman, A. (2005). Inhibition of Mammalian Target of Rapamycin Potentiates Thrombin-Induced Intercellular Adhesion Molecule-1 Expression by Accelerating and Stabilizing NF-κB Activation in Endothelial Cells. The Journal of Immunology, 174(9), 5823–5829. https://doi.org/10.4049/jimmunol.174.9.5823
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