Exogenous clustered neuropilin 1 enhances vasculogenesis and angiogenesis.
Neuropilin 1 (NP-1) is a receptor for vascular endothelial growth factor (VEGF) 165 (VEGF165) and acts as a coreceptor that enhances VEGF165 function through tyrosine kinase VEGF receptor 2 (VEGFR-2). Transgenic overexpression of np-1 results in an excess of capillaries and blood vessels and a malformed heart. Thus, NP-1 may have a key role in vascular development. However, how NP-1 regulates vascular development is not well understood. This study demonstrates how NP-1 can regulate vasculogenesis and angiogenesis in vitro and in vivo. In homozygous np-1 mutant (np-1(-/-)) murine embryos, vascular sprouting was impaired in the central nervous system and pericardium. Para-aortic splanchnopleural mesoderm (P-Sp) explants from np-1(-/-) mice also had vascular defects in vitro. A monomer of soluble NP-1 (NP-1 tagged with Flag epitope) inhibited vascular development in cultured wild-type P-Sp explants by sequestering VEGF165. In contrast, a dimer of soluble NP-1 (NP-1 fused with the Fc part of human IgG) enhanced vascular development in cultured wild-type P-Sp explants. Moreover, the NP-1-Fc rescued the defective vascular development in cultured np-1(-/-) P-Sp explants. A low dose of VEGF alone did not promote phosphorylation of VEGFR-2 on endothelial cells from np-1(-/-) embryos, but simultaneous addition of a low dose of VEGF and NP-1-Fc phosphorylated VEGFR-2 significantly. Moreover, NP-1-Fc rescued the defective vascularity of np-1(-/-) embryos in vivo. These results suggest that a dimer form of soluble NP-1 delivers VEGF165 to VEGFR-2-positive endothelial cells and promotes angiogenesis.
Yamada
Y
Y
Department of Cell Differentiation, Institute of Molecular Embryology and Genetics, University School of Medicine, Kumamoto, Japan.
Takakura
N
N
Yasue
H
H
Ogawa
H
H
Fujisawa
H
H
Suda
T
T
D000818:Animals; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects; D019281:Dimerization; D004357:Drug Synergism; D004622:Embryo, Mammalian; D016228:Endothelial Growth Factors / Q000378:metabolism / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D006801:Humans; D008222:Lymphokines / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D008817:Mice, Mutant Strains; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000494:pharmacology* / Q000502:physiology; D039942:Neuropilin-1; D010766:Phosphorylation / Q000187:drug effects; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D009419:Nerve Tissue Proteins; D017978:Receptors, Growth Factor; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D039942:Neuropilin-1; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor