Egr-3 is required for VEGF-mediated induction of leukocyte adhesion to primary human endothelial cells. HUVECs were transfected with si-Control, si-Egr-3 oligo1, or si-Egr-3 oligo2 (A) or preincubated with control IgG or antibodies against E-selectin, VCAM-1 (B) and treated with or without 50 ng/mL VEGF for 6 hours. PKH26-stained U937 monocytes were plated on top of HUVEC monolayers and incubated for 90 minutes. After washing, adhered U937 cells were observed under fluorescent and phase-contrast microscopy. Adhesion levels were quantified on the basis of fluorescent intensity by the use of image analysis software. The mean ± SD was derived from 3 arbitral optical images with 5 independent experiments (bar graph). *P < .01 compared with si-Control plus VEGF.