title: Oligo-guanosine nucleotide induces neuropilin-1 internalization in endothelial cells and inhibits angiogenesis.
abstract: Ligand interaction with cognate cell-surface receptor often promotes receptor internalization, protecting cells from prolonged or excessive signaling from extracellular ligands. Compounds that induce internalization of surface receptors prevent ligand binding to cognate cell-surface receptors serving as inhibitors. Here, we show that synthetic polyriboguanosine (poly G) and oligo-deoxyriboguanosine (oligo G) reduce endothelial levels of surface neuropilin-1 (NRP1), a receptor shared by semaphorin 3A and vascular endothelial growth factor (VEGF), which plays critical roles in angiogenesis. Oligo G also reduces levels of cell-surface scavenger receptor expressed by endothelial cells I (SREC-I), but not levels of NRP2, gp130, CD31, VEGFR-1, or VEGFR-2. Poly or oligo A, T, and C do not promote NRP1 or SREC-I internalization. We find that oligo G binds to NRP1 with high affinity (Kd:1.3 ± 0.16 nM), bridges the extracellular domain of NRP1 to that of SREC-I, and induces coordinate internalization of NRP1 and SREC-I. In vitro, oligo G blocks the binding and function of VEGF(165) in endothelial cells. In vivo, intravitreal administration of oligo G reduces choroidal neovascularization in mice. These results demonstrate that synthetic oligo G is an inhibitor of pathologic angiogenesis that reduces cell-surface levels and function of NRP1 acting as an internalization inducer.
authors.affiliation: Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1907, USA.
authors.forename: Masashi
authors.initials: M
authors.lastname: Narazaki
authors.forename: Marta
authors.initials: M
authors.lastname: Segarra
authors.forename: Xu
authors.initials: X
authors.lastname: Hou
authors.forename: Toshio
authors.initials: T
authors.lastname: Tanaka
authors.forename: Xuri
authors.initials: X
authors.lastname: Li
authors.forename: Giovanna
authors.initials: G
authors.lastname: Tosato
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D006151:Guanosine / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D039942:Neuropilin-1 / Q000378:metabolism*; D009841:Oligonucleotides / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D009841:Oligonucleotides; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D006151:Guanosine; D039942:Neuropilin-1