title: Modulation of VEGFR-2-mediated endothelial-cell activity by VEGF-C/VEGFR-3.
abstract: Vascular endothelial growth factor (VEGF) receptor 3 (VEGFR-3), a receptor for VEGF-C, was shown to be essential for angiogenesis as well as for lymphangiogenesis. Targeted disruption of the VEGFR-3 gene in mice and our previous study using an antagonistic monoclonal antibody (MoAb) for VEGFR-3 suggested that VEGF-C/VEGFR-3 signals might be involved in the maintenance of vascular integrity. In this study we used an in vitro embryonic stem (ES) cell culture system to maintain the VEGFR-3(+) endothelial cell (EC) and investigated the role of VEGFR-3 signals at the cellular level. In this system packed clusters of ECs were formed. Whereas addition of exogenous VEGF-A induced EC dispersion, VEGF-C, which can also stimulate VEGFR-2, promoted EC growth without disturbing the EC clusters. Moreover, addition of AFL4, an antagonistic MoAb for VEGFR-3, resulted in EC dispersion. Cytological analysis showed that VEGF-A- and AFL4-treated ECs were indistinguishable in many aspects but were distinct from the cytological profile induced by antagonistic MoAb for VE-cadherin (VECD-1). As AFL4- induced EC dispersion requires VEGF-A stimulation, it is likely that VEGFR-3 signals negatively modulate VEGFR-2. This result provides new insights into the involvement of VEGFR-3 signals in the maintenance of vascular integrity through modulation of VEGFR-2 signals. Moreover, our findings suggest that the mechanisms underlying AFL4-induced EC dispersion are distinct from those underlying VECD-1-induced dispersion for maintenance of EC integrity.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Graduate School of Medicine, Kyoto University, Japan. kazuy@kuhp.hyoto-u.ac.jp
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Matsumura
authors.forename: Masanori
authors.initials: M
authors.lastname: Hirashima
authors.forename: Minetaro
authors.initials: M
authors.lastname: Ogawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Kubo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hisatsune
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kondo
authors.forename: Satomi
authors.initials: S
authors.lastname: Nishikawa
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Chiba
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Nishikawa
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD; D015820:Cadherins / Q000276:immunology / Q000502:physiology; D002449:Cell Aggregation / Q000187:drug effects; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004622:Embryo, Mammalian / Q000166:cytology; D016228:Endothelial Growth Factors / Q000494:pharmacology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D015870:Gene Expression; D051379:Mice; D018345:Mice, Knockout; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013234:Stem Cells; D042461:Vascular Endothelial Growth Factor A; D042582:Vascular Endothelial Growth Factor C; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000502:physiology*; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D000099152:Cadherin 5
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015820:Cadherins; D016228:Endothelial Growth Factors; D042461:Vascular Endothelial Growth Factor A; D042582:Vascular Endothelial Growth Factor C; D040301:Vascular Endothelial Growth Factor Receptor-2; D040321:Vascular Endothelial Growth Factor Receptor-3; D000099152:Cadherin 5