title: Ras signaling directs endothelial specification of VEGFR2+ vascular progenitor cells.
abstract: Vascular endothelial growth factor receptor 2 (VEGFR2) transmits signals of crucial importance to vasculogenesis, including proliferation, migration, and differentiation of vascular progenitor cells. Embryonic stem cell-derived VEGFR2(+) mesodermal cells differentiate into mural lineage in the presence of platelet derived growth factor (PDGF)-BB or serum but into endothelial lineage in response to VEGF-A. We found that inhibition of H-Ras function by a farnesyltransferase inhibitor or a knockdown technique results in selective suppression of VEGF-A-induced endothelial specification. Experiments with ex vivo whole-embryo culture as well as analysis of H-ras(-/-) mice also supported this conclusion. Furthermore, expression of a constitutively active H-Ras[G12V] in VEGFR2(+) progenitor cells resulted in endothelial differentiation through the extracellular signal-related kinase (Erk) pathway. Both VEGF-A and PDGF-BB activated Ras in VEGFR2(+) progenitor cells 5 min after treatment. However, VEGF-A, but not PDGF-BB, activated Ras 6-9 h after treatment, preceding the induction of endothelial markers. VEGF-A thus activates temporally distinct Ras-Erk signaling to direct endothelial specification of VEGFR2(+) vascular progenitor cells.
authors.affiliation: Department of Molecular Pathology, Graduate School of Medicine, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kawasaki
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Watabe
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sase
authors.forename: Masanori
authors.initials: M
authors.lastname: Hirashima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Koide
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Morishita
authors.forename: Keiko
authors.initials: K
authors.lastname: Yuki
authors.forename: Toshikuni
authors.initials: T
authors.lastname: Sasaoka
authors.forename: Toshio
authors.initials: T
authors.lastname: Suda
authors.forename: Motoya
authors.initials: M
authors.lastname: Katsuki
authors.forename: Kohei
authors.initials: K
authors.lastname: Miyazono
authors.forename: Keiji
authors.initials: K
authors.lastname: Miyazawa
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D004622:Embryo, Mammalian / Q000166:cytology; D053595:Embryonic Stem Cells / Q000166:cytology; D042783:Endothelial Cells / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008715:Methionine / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; C096856:FTI 277; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; D008715:Methionine; D040301:Vascular Endothelial Growth Factor Receptor-2; C495971:Hras protein, mouse; D016283:Proto-Oncogene Proteins p21(ras)