Abstract

Roles of vascular endothelial growth factor receptor 3 signaling in differentiation of mouse embryonic stem cell–derived vascular progenitor cells into endothelial cells Hiroyuki Suzuki, Tetsuro Watabe, Mitsuyasu Kato, Keiji Miyazawa, and Kohei Miyazono Vascular endothelial growth factor recep-tor 2 (VEGFR2/Flk-1)–positive cells de-rived from embryonic stem (ES) cells serve as vascular progenitors, which dif-ferentiate into endothelial cells (ECs) in the presence of VEGF-A. VEGFR3/Flt-4 (fms-like tyrosine kinase 4) signaling is known to be important for the develop-ment of lymphatic endothelial cells (LECs). To elucidate the roles of VEGFR3 signaling in the differentiation of vascular progenitor cells into ECs, we introduced various types of VEGFR3 cDNAs into mouse ES cells. VEGF-C, a ligand for VEGFR2 and VEGFR3, stimulated the en-dothelial differentiation of the VEGFR2 cells transfected with the VEGFR3 cDNA but not those transfected with kinase-negative mutants of VEGFR3. The VEGFR3-transfected ECs exhibited high expression levels of lymphatic vessel en-dothelial hyaluronan receptor-1 (LYVE-1), one of the markers of LECs, and showed efficient binding of hyaluronan. VEGF-C(C152S), which is able to activate VEGFR3 but not VEGFR2, failed to induce the endothelial differentiation of mock-and VEGFR3-transfected VEGFR2 cells, suggesting the essential role of VEGFR2 signaling for endothelial differentiation. Furthermore, kinase-negative mutants of VEGFR3 prevented the VEGF-C–medi-ated endothelial differentiation of the vas-cular progenitor cells. Thus, VEGFR2 sig-naling is required for the endothelial differentiation of mouse ES cells induced by VEGF-C, and VEGFR3 signaling may confer lymphatic endothelial-like pheno-types to ECs. (Blood. 2005;105:2372-2379)