NRP1 and Patent ductus arteriosus: Our IHC and IF staining against the NRP1 antibody on a slide using partially ligated carotid artery data indicated that NRP1 expression was significantly induced after PDA treatment for 7 days, and enhanced expression of NRP1 was exhibited in the neointima area and endothelial cells, with dramatically enhanced expression of NRP1 located in the endothelial layer (Figure 4G,H; Supplementary Figure S7A,B).