Fig. 2

Fig. 2

Inhibition of Vegfr signaling with a high dose of SU5416 decreases vascular endothelial differentiation while low doses of SU5416 inhibit arterial and promote venous specification. (A-T) In situ hybridization analysis of arterial (cldn5b), venous (stab1l, dab2) and pan-endothelial (etv2) marker expression in embryos treated with 2.5–20 μM doses of SU5416 starting at the 50% epiboly stage. Note that cldn5b expression is reduced in embryos treated with all doses of SU5416, while stab1l expression appears to be only mildly downregulated or unchanged at the lowest dose of SU5416. In contrast, dab2 expression is expanded into the artery in embryos treated with 2.5–10 μM doses (G,K,O), and reduced in embryos treated with a 20 μM dose (S). The expression of etv2 is reduced in embryos treated with medium and high doses of 5–20 μM SU5416 (L,P,T). Lateral view of 24 hpf embryos, anterior to the left. Arrows indicate the DA and arrowheads indicate the PCV. Numbers of embryos showing the displayed phenotype are listed. (U) qPCR analysis of arterial (cldn5b, aqp8a), venous (flt4, stab1l, dab2, lyve1b, mrc1a) and pan-endothelial (cdh5, etv2) markers in 24hpf-old embryos treated with varied doses of SU5416 starting at the 50% epiboly stage. Note that arterial cldn5b and aqp8a expression is reduced at all doses of treatment; pan-endothelial cdh5 and etv2 as well as venous flt4, stab1l and lyve1b expression is only mildly downregulated or not changed in embryos treated with low 2.5–5 μM doses of SU5416, and strongly downregulated in embryos treated with higher 10–20 μM doses; venous dab2 expression is upregulated in embryos treated with low doses, and downregulated only in embryos treated with the highest (20 μM) SU5416 dose. * indicates p<0.05 and ** indicates p<0.01, ±SEM is shown.