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Fig. 4 Loss of Nrarp Expression Causes Vessel Regression in Mouse and Zebrafish
(A and B) Nrarp-/- retinas display ectopic vessel regression at vascular front. P5 Nrarp+/+ and Nrarp-/- retinas labeled for Isolectin-B4 (blue) and collagen IV (red). Arrowheads highlight empty collagen IV sleeves, indicating vessel regression.
(C and D) P6 Nrarp+/+ and Nrarp-/- retinas labeled for Claudin 5 (green in [C″′ and D″′]), collagen IV (red in [C″′ and D″′]), and Isolectin-B4 (blue in [C″′ and D″′]). Increased vessel regression (arrowheads, [D′]) associates with discontinuous endothelial junctions in Nrarp-/- retinas (arrows, [D]). (D″) and (D″′) correspond to boxed regions in (D) and (D′). Yellow arrows indicate punctate Claudin 5 staining; white arrows point to loss of Claudin 5 continuity between vessels.
(E) Ratio of Isolectin-B4-positive vessels to collagen IV-positive vessels. Values below 1 indicate vessel regression. ***, p < 0.0005. Nrarp+/+, n = 13; Nrarp+/-, n = 8; Nrarp-/-, n = 20.
(F and G) Zona occludens 1 (ZO1, red) staining in uninjected and nrarp-a MO-injected Tg(fli1:EGFP)y1 zebrafish embryos at 48 hpf. (F′) and (G′), high magnification Z-stacks of boxed regions in (F) and (G). Endothelial junctions (illustrated by red tracing) between the ISV and DA are poorly developed in nrarp-a morphants (arrow in [G′]).
Reprinted from Developmental Cell, 16(1), Phng, L.K., Potente, M., Leslie, J.D., Babbage, J., Nyqvist, D., Lobov, I., Ondr, J.K., Rao, S., Lang, R.A., Thurston, G., and Gerhardt, H., Nrarp coordinates endothelial Notch and Wnt signaling to control vessel density in angiogenesis, 70-82, Copyright (2009) with permission from Elsevier. Full text @ Dev. Cell