title: Specialized tip/stalk-like and phalanx-like endothelial cells from embryonic stem cells.
abstract: Endothelial cells (EC) generated in vitro from stem cells are desirable for their potential in a variety of in vitro models and cell-based therapeutic approaches; however, EC can take on a number of functionally and phenotypically distinct specializations. Here, we show the generation of functionally distinct EC subpopulations, including (1) the pro-angiogenic migrating tip-like and proliferative stalk-like EC, and (2) the less migratory cobblestone-shaped phalanx-like EC. Both embryonic stem cell (ESC)-derived EC subpopulations are generated from outgrowths of Flk-1+ vascular progenitor cells with high levels of vascular endothelial growth factor treatment, while the phalanx-like ESC-derived EC (ESC-EC) are subsequently isolated by selecting for cobblestone shape. Compared with the ESC-derived angiogenic endothelial cells (named ESC-AEC) that contain only 14% Flt-1+ and 25% Tie-1+ cells, the selected phalanx-like ESC-EC express higher numbers of cells expressing the phalanx markers Flt-1+ and Tie-1+, 89% and 90%, respectively. The ESC-AEC also contain 35% CXCR4+ tip cells, higher expression levels of stalk marker Notch-1, and lower expression levels of Tie-2 compared with the phalanx-type ESC-EC that do not contain discernible numbers of CXCR4+ tip cells. Perhaps most notably, the ESC-AEC display increased cell migration, proliferation, and 3 times more vessel-like structures after 48 h on Matrigel compared with the phalanx-like ESC-EC. This work analyzes, for the first time, the presence of distinct EC subtypes (tip/stalk, and phalanx) generated in vitro from ESC, and shows that phalanx-like EC can be purified and maintained in culture separate from the tip/stalk-like containing EC.
authors.affiliation: Graduate Program in Quantitative and Systems Biology, University of California , Merced, California, USA.
authors.forename: Alicia A
authors.initials: AA
authors.lastname: Blancas
authors.forename: Lian E
authors.initials: LE
authors.lastname: Wong
authors.forename: Drew E
authors.initials: DE
authors.lastname: Glaser
authors.forename: Kara E
authors.initials: KE
authors.lastname: McCloskey
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002465:Cell Movement; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000502:physiology*; D042783:Endothelial Cells / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology; D051379:Mice; D018919:Neovascularization, Physiologic; D010641:Phenotype; D042787:Receptor, TIE-2 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism
chemical_list: D015415:Biomarkers; C514936:CXCR4 protein, mouse; D019718:Receptors, CXCR4; D042787:Receptor, TIE-2; C079086:Tek protein, mouse