Cytokine-regulated expression of E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in human microvascular endothelial cells

Abstract

Endothelial cells (EC) recruit circulating leukocytes to sites of inflammation, partly by expression of endothelial-leukocyte adhesion molecules. Whereas the regulation of some adhesion molecules is well characterized in cultured HUVEC, similar data for microvascular human test systems are limited. We studied the cytokine-regulated expression of vascular cell adhesion molecules E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in cultured human intestinal microvascular endothelial cells (HIMEC). E-selectin and VCAM-1 were induced, and ICAM-1 was enhanced, in a dose-dependent fashion after stimulation with IL-1beta, TNF-alpha, and LPS. Each adhesion molecule displayed characteristic time-related responses comparable to those obtained with HUVEC, and each molecule supported adhesion of leukocytes. Notable disparities between the two endothelial test systems were that 1) expression of total cellular E-selectin (but not surface membrane expression) was sustained after 72 h of IL-1beta stimulation in HIMEC, contrasting a rapid biphasic response in HUVEC; 2) LPS did not maintain prolonged expression of ICAM-1 and VCAM-1 in HIMEC; and 3) VCAM-1 protein was dose-dependently up-regulated by IL-4 in HUVEC, peaking after 8 h, while IL-4 had only a negligible effect on the expression of this protein in HIMEC. In conclusion, the regulation of these adhesion molecules appears to be somewhat different in HIMEC compared with HUVEC, and the differences from available data on skin-derived microvascular endothelial cell cultures are to some extent substantial. Our findings document the importance of using relevant endothelial cell culture systems for studies of leukocyte-endothelial cell interactions.