Histamine and serotonin, but not VEGF-A165, activate the TSP-1 promoter, but not directly through TR3. (A) HUVEC were transduced with TSP-1 promoter luciferase and internal luciferase constructs and then were stimulated with histamine (10 μM) (left panel), serotonin (10 μM) (right panel), or VEGF-A165 (10 ng/mL) (both panels) as indicated (n = 6; experiments were repeated 3 times). ***P < .001 vs control, Tukey-Kramer multiple comparisons test. (B) Cell extracts from HUVEC that were not transduced or transduced with LacZ (control) or with TR3 cDNAs were subjected to immunoblotting with antibodies against TSP-1 (top panel), VE-cadherin (middle panel), and β-actin for protein equal loading control (bottom panel). Data are representative of 3 independent experiments.