title: Sulfated polysaccharides identified as inducers of neuropilin-1 internalization and functional inhibition of VEGF165 and semaphorin3A.
abstract: Neuropilin-1 (NRP1) and NRP2 are cell surface receptors shared by class 3 semaphorins and vascular endothelial growth factor (VEGF). Ligand interaction with NRPs selects the specific signal transducer, plexins for semaphorins or VEGF receptors for VEGF, and promotes NRP internalization, which effectively shuts down receptor-mediated signaling by a second ligand. Here, we show that the sulfated polysaccharides dextran sulfate and fucoidan, but not others, reduce endothelial cell-surface levels of NRP1, NRP2, and to a lesser extent VEGFR-1 and VEGFR-2, and block the binding and in vitro function of semaphorin3A and VEGF(165). Administration of fucoidan to mice reduces VEGF(165)-induced angiogenesis and tumor neovascularization in vivo. We find that dextran sulfate and fucoidan can bridge the extracellular domain of NRP1 to that of the scavenger receptor expressed by endothelial cells I (SREC-I), and induce NRP1 and SREC-I coordinate internalization and trafficking to the lysosomes. Overexpression of SREC-I in SREC-I-negative cells specifically reduces cell-surface levels of NRP1, indicating that SREC-I mediates NRP1 internalization. These results demonstrate that engineered receptor internalization is an effective strategy for reducing levels and function of cell-surface receptors, and identify certain sulfated polysaccharides as "internalization inducers."
authors.affiliation: The 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: Giovanna
authors.initials: G
authors.lastname: Tosato
mesh_terms: D000818:Animals; D002460:Cell Line; D016264:Dextran Sulfate / Q000494:pharmacology*; D004705:Endocytosis / Q000187:drug effects*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D051907:Lysosomal Membrane Proteins / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects; D039942:Neuropilin-1 / Q000737:chemistry / Q000378:metabolism*; D011134:Polysaccharides / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D051128:Scavenger Receptors, Class F / Q000378:metabolism; D040121:Semaphorin-3A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D052118:Lysosomal-Associated Membrane Protein 1
chemical_list: D016264:Dextran Sulfate; D051907:Lysosomal Membrane Proteins; D039942:Neuropilin-1; D011134:Polysaccharides; D051128:Scavenger Receptors, Class F; D040121:Semaphorin-3A; D042461:Vascular Endothelial Growth Factor A; C489116:LAMP1 protein, human; D052118:Lysosomal-Associated Membrane Protein 1; C495126:SCARF1 protein, human; C467484:VEGFA protein, human; C007789:fucoidan