title: Vascular endothelial growth factor receptor-2 and low affinity VEGF binding sites on human glomerular endothelial cells: Biological effects and advanced glycosilation end products modulation.
abstract: Vascular Endothelial Growth Factor (VEGF), binding to its receptor in endothelial cells, seems to modulate the increased blood flow in the early phase of diabetic renal disease. The aim of the study was to evaluate, in a diabetic milieu, the expression, biological function and modulation of VEGF binding sites in human glomerular endothelial cells (GENC). We demonstrated the presence of VEGF binding sites with high (VEGFR-2) and low (heparan sulfate proteoglycans, HSPG) affinity. VEGF165 and VEGF121 working through VEGFR-2 stimulated nitric oxide (NO) production at low doses (0.1-1 nM), whereas only VEGF165 at high doses (10-100 nM) increased thymidine incorporation. 1 nM VEGF165 and VEGF121 induced in GENC a significant peak of inducible NO synthase (iNOS) production and, at a lower level, of endothelial NOS (eNOS). The copresence of VEGF165 with aminoguanidine (iNOS inhibitor) determined an increase of eNOS and a significant increase in thymidine incorporation. Advanced glycation end products (AGEs) working through specific receptors (RAGE) up-regulated the expression of VEGFR-2, decreased the expression of HSPG sites and reduced GENC growth. These results identify in GENC VEGFR-2 as a mediator of iNOS and eNOS release under control of VEGF, whereas HSPG binding sites seem to mediate the weak growth effect. The presence of AGEs, up-regulating the VEGFR-2 and decreasing HSPG sites might participate to the block of glomerular angiogenesis addressing the VEGF effects on glomerular permeability.
authors.affiliation: Department of Clinical Pathophysiology, Endocrinology Unit, Diabetes and Metabolic Diseases Section, University of Florence, viale Pieraccini 6-501354 Florence, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Pala
authors.forename: Barbara
authors.initials: B
authors.lastname: Cresci
authors.forename: Cinzia
authors.initials: C
authors.lastname: Manuelli
authors.forename: Enrico
authors.initials: E
authors.lastname: Maggi
authors.forename: Yoko F
authors.initials: YF
authors.lastname: Yamaguchi
authors.forename: Pietro
authors.initials: P
authors.lastname: Cappugi
authors.forename: Carlo Maria
authors.initials: CM
authors.lastname: Rotella
authors.forename: Stefano
authors.initials: S
authors.lastname: Giannini
mesh_terms: D000367:Age Factors; D001665:Binding Sites; D015153:Blotting, Western; D002478:Cells, Cultured; D003928:Diabetic Nephropathies / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000737:chemistry* / Q000378:metabolism; D006146:Guanidines / Q000737:chemistry / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D006493:Heparin / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D007678:Kidney Glomerulus / Q000378:metabolism*; D007700:Kinetics; D008024:Ligands; D008833:Microcirculation; D009389:Neovascularization, Pathologic; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D012313:RNA / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D013936:Thymidine / Q000737:chemistry; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry* / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism / Q000502:physiology*
chemical_list: D017127:Glycation End Products, Advanced; D006146:Guanidines; D019812:Heparan Sulfate Proteoglycans; D008024:Ligands; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D009569:Nitric Oxide; D012313:RNA; D006493:Heparin; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D040301:Vascular Endothelial Growth Factor Receptor-2; C004479:pimagedine; D013936:Thymidine