Graduate Program in Quantitative and Systems Biology, University of California , Merced, California, USA.
Stem Cells Dev. 2013 May 1;22(9):1398-407. doi: 10.1089/scd.2012.0376. Epub 2013 Feb 12.
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.
体外从干细胞生成的内皮细胞因其在各种体外模型和基于细胞的治疗方法中的潜在应用而受到关注；然而，内皮细胞可以呈现出许多功能和表型上明显不同的特化。在这里，我们展示了功能不同的内皮细胞亚群的产生，包括（1）促血管生成的迁移尖端样和增殖茎干样内皮细胞，和（2）迁移能力较弱的鹅卵石状板层样内皮细胞。两种胚胎干细胞（ESC）衍生的内皮细胞亚群都是从 Flk-1+血管祖细胞的生长中产生的，这些祖细胞经过高水平的血管内皮生长因子处理，而鹅卵石状板层样 ESC 衍生的内皮细胞（ESC-EC）随后通过选择鹅卵石形状进行分离。与仅含有 14%的 Flt-1+和 25%的 Tie-1+细胞的 ESC 衍生的血管生成内皮细胞（命名为 ESC-AEC）相比，选择的鹅卵石状板层样 ESC-EC 表达更高数量的表达板层标志物 Flt-1+和 Tie-1+的细胞，分别为 89%和 90%。ESC-AEC 还含有 35%的 CXCR4+尖端细胞，比板层型 ESC-EC 更高的茎干标志物 Notch-1 的表达水平，以及更低的 Tie-2 表达水平，而板层型 ESC-EC 中没有可识别数量的 CXCR4+尖端细胞。也许最值得注意的是，与板层状 ESC-EC 相比，ESC-AEC 在 Matrigel 上培养 48 小时后，细胞迁移、增殖和 3 倍多的血管样结构增加。这项工作首次分析了从 ESC 体外生成的不同内皮细胞亚型（尖端/茎干和板层）的存在，并表明板层状 ESC 可以在与包含尖端/茎干样细胞的细胞分离和保持在培养中。
