Induction Of Vascular Cell Adhesion Molecule-1 Expression By Il-4 In Human Aortic Smooth Muscle Cells Is Not Associated With Increased Nuclear Nf-Kappa B Levels

Vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) are upregulated in vascular endothelial and smooth muscle cells by cytokines produced at sites of inflammation. The cytokine profile for induction of VCAM-1, however, is different for the two cell types. Tumor necrosis factor-alpha (TNF-alpha) induced both VCAM-1 and ICAM-1 expression in human umbilical vein endothelial cells (HUVECs; ED50 similar to 300 and 30 U/ml, respectively). TNF-alpha and interleukin-1 beta (IL-1 beta) stimulated cell surface ICAM-1 expression, but not VCAM-1 expression, in human aortic smooth muscle cells (HASMCs). Conversely, IL-4 was a potent VCAM-1 inducer in HASMCs (ED50 similar to 100 pg/ml) but did not induce ICAM-1 expression. Nuclear extracts from IL-4-treated cells were compared with untreated cells for relative nuclear factor-kappa 9 (NF-kappa B) revels by using an electrophoretic mobility shift assay and surface plasmon resonance techniques. No significant increase in nuclear NF-kappa B DNA binding activity was detected in IL-4-treated HASMCs by either method of analysis. IL-1 beta and TNF-alpha stimulated nuclear NF-kappa B levels by about fourfold and fivefold, respectively, in HASMCs. The antioxidant pyrrolidine dithiocarbamate (PDTC) similarly inhibited VCAM-1 upregulation in HASMCs incubated with IL-4 and in HUVECs incubated with TNF-alpha (IC(50)s of 25 and 40 mu M, respectively). These data suggest that a significant increase in nuclear NF-kappa B levels is not necessary or sufficient for VCAM-1 upregulation in HASMCs and does not determine the relative sensitivity to inhibition of gene expression by PDTC. (C) 1999 Wiley-Liss, Inc.