Activation agonists result in rapid, high-level induction of Egr-3 in primary human endothelial cells. (A) DNA microarrays of HUVECs treated with 50 ng/mL VEGF, 2 U/mL thrombin, or 10 ng/mL TNF-α for 1, 4 or 18 hours. Shown is Venn diagram of agonist-induced genes. (B) Real-time PCR time-course analysis of Egr-1 and -3 mRNA expression in VEGF-treated HUVECs, HCAECs, HPAECs, and HDMVECs. *P < .001 compared with 0 hours (no treatment) in HUVECs, HCAECs, HPAECs, and HDMVECs. (C) Time-dependent induction of Egr-1 and -3 protein expression in VEGF-stimulated HUVECs. Western blot analysis was performed by the use of antibodies against Egr-1 or -3. Antinucleoporin antibody was used as an internal loading control. The data are representative of 3 independent experiments.