title: Vascular endothelial growth factor regulates stanniocalcin-1 expression via neuropilin-1-dependent regulation of KDR and synergism with fibroblast growth factor-2.
abstract: Stanniocalcin-1 (STC-1) is a glycoprotein hormone originally identified as a regulator of calcium and phosphate homeostasis in bony fish. Up-regulation of the mammalian homolog in numerous gene profiling studies of angiogenesis and vascular endothelial growth factor-A (VEGF-A(165))-regulated gene expression, suggests that regulation of this factor may be a key feature of the angiogenic response. Here we investigated the mechanisms mediating VEGF-A(165)-induced STC-1 gene expression in human endothelial cells. VEGF-A(165), acting via VEGFR2/KDR, induced STC-1 through de novo transcription, mediated primarily via intracellular protein kinase C (PKC)- and extracellular signal-regulated protein kinase (ERK)-dependent pathways. VEGF-A(165)-induced STC-1 mRNA expression was synergistically enhanced up to 2-fold by co-treatment with FGF-2, in a mechanism dependent on VEGFR2/KDR and FGFR1. Production of STC-1 protein by endothelial cells was also induced by VEGF-A(165) and synergistically enhanced by co-treatment with FGF-2. Synergism between VEGF-A(165) and FGF-2 was mediated via a novel neuropilin-1 (NP-1)-dependent mechanism, as indicated by the complete inhibition of synergism with either EG3287, a specific neuropilin antagonist, or siRNA-mediated NP-1 knockdown, and by the inability of the VEGF-A(121) isoform to synergise with FGF-2. Surprisingly, we found that NP-1 knockdown also markedly reduced KDR expression in HUVECs, and enhanced the VEGF-A(165)-induced reduction in KDR expression resulting from receptor-mediated endocytosis. These findings support a role for NP-1 in mediating synergistic effects between VEGF-A(165) and FGF-2, which may occur in part through a contribution of NP-1 to KDR stability.
authors.affiliation: Centre for Cardiovascular Biology and Medicine, BHF Laboratories, Department of Medicine, University College London, 5 University Street, London, United Kingdom.
authors.forename: David I R
authors.initials: DI
authors.lastname: Holmes
authors.forename: Ian C
authors.initials: IC
authors.lastname: Zachary
mesh_terms: D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018919:Neovascularization, Physiologic; D039942:Neuropilin-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014158:Transcription, Genetic; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism* / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D010446:Peptide Fragments; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C511613:vascular endothelial growth factor A (138-165); D016222:Fibroblast Growth Factor 2; D039942:Neuropilin-1; C051795:teleocalcin; C496348:FGFR1 protein, human; D051496:Receptor, Fibroblast Growth Factor, Type 1; D040301:Vascular Endothelial Growth Factor Receptor-2; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases