Interleukin-4 induces endothelial vascular cell adhesion molecule-1 (VCAM-1) by an NF-kappa b-independent mechanism

While all features of the inflammatory response induced by IL-1 are not observed following IL-4 stimulation, suboptimal concentrations both cytokines result in synergistic VCAM-1 expression in HUVEC. We have shown that, while IL-1 stimulated HUVEC express GM-CSF, tissue factor and VCAM-1, only VCAM-1 is detectable after exposure to IL-4. While kB was found essential for both basal and IL-1-mediated activity of VCAM-1, IL-4 induction was kB-independent. Inducible kB-binding proteins were identified in IL-1-, but not IL-4-stimulated nuclear extracts. Our results indicate that IL-4 exerts its transcriptional effects on the VCAM-1 gene through element(s) which do not require kB.