TSP-1 inhibits VEGF induced VEGFR2 phosphorylation through CD47.

<p>(A) Late EPCs were treated with VEGF (25 ng/ml) for 0, 5, 10, 15 min respectively. Total protein was extracted and the expression of FLK-1, phospho-VEGFR2 (Tyr1175) was determined by Western blot. (B)Seventy-two hrs after transfection of CD47-specific siRNA or control siRNA, the expression of CD47 in late EPCs was determined by western blotting analysis in three independent experiments (#p<0.05 versus control siRNA). (C)Seventy-two hrs after transfection of CD47-specific siRNA or control siRNA, late EPCs were treated with TSP-1(2 µg/ml) for 30 min and then VEGF(25 ng/ml) for 5 min. Total protein was extracted and the expression of FLK-1, phospho-VEGFR2 (Tyr1175) was determined by Western blot analysis. (D) Quantification of VEGFR2 phosphorylation normalized to VEGFR2 in three independent experiments(#p<0.05 versus control siRNA, *p<0.01 versus control siRNA).