A requirement for neuropilin-1 in embryonic vessel formation

Neuropilin-1 is a membrane protein that is expressed in developing neurons and functions as a receptor or a component of the receptor complex for the class 3 semaphorins, which are inhibitory axon guidance signals. Targeted i nactivation of the neuropilin-1 gene in mice induced disorganization of the pathway and projection of nerve fibers, suggesting that neuropilin-1 media tes semaphorin-elicited signals and regulates nerve fiber guidance in embry ogenesis. Neuropilin-1 is also expressed in endothelial cells and shown to bind vascular endothelial growth factor (VEGF), a potent regulator for vasc ulogenesis and angiogenesis. However, the roles of neuropilin-1 in vascular formation have been unclear. This paper reported that the neuropilin-1 mut ant mouse embryos exhibited various types of vascular defects, including im pairment in neural vascularization, agenesis and transposition of great ves sels, insufficient aorticopulmonary truncus (persistent truncus arteriosus) , and disorganized and insufficient development of vascular networks in the yolk sac, The vascular defects induced by neuropilin-1 deficiency in mouse embryos suggest that neuropilin-1 plays roles in embryonic vessel formatio n, as well as nerve fiber guidance.