Vavilov Institute of General Genetics RAS and LKT Ltd., Moscow, Russia.
Cell Cycle. 2010 Mar 1;9(5):937-46. doi: 10.4161/cc.9.5.10869. Epub 2010 Mar 6.
Reprogramming of a limited number of human cell types has been achieved through ectopic expression of four transcription factors to yield induced pluripotent stem (iPS) cells that closely resemble human embryonic stem cells (ESCs). Here, we determined functional and epigenetic properties of iPS cells generated from human umbilical vein endothelial cells (HUVEC) by conventional method of direct reprogramming. Retroviral overexpression of four transcription factors resets HUVEC to the pluripotency. Human endothelial cell-derived iPS (endo-iPS) cells were similar to human ESCs in morphology, gene expression, in vitro and in vivo differentiation capacity. Endo-iPS cells were efficiently differentiated in vitro into endothelial cells. Using genome-wide methylation profiling we show that promoter elements of endothelial specific genes were methylated following reprogramming whereas pluripotency-related gene promoters were hypomethylated similar to levels observed in ESCs. Genome-wide methylation analysis of CpG sites located in the functional regions of over than 14,000 genes indicated that human endo-iPS cells were highly similar to human ES cells, although differences in methylation levels of 46 genes were found. Overall CpG methylation of promoter regions in the pluripotent cells was higher than in somatic. We also show that during reprogramming female human endo-iPS cells exhibited reactivation of the somatically silenced X chromosome. Our findings demonstrate that iPS cells can be generated from human endothelial cells and reprogramming resets epigenetic status of endothelial cells to pluripotency.
通过异位表达四种转录因子，已经实现了为数有限的人类细胞类型的重编程，从而产生了与人类胚胎干细胞（ESCs）非常相似的诱导多能干细胞（iPS）细胞。在这里，我们通过直接重编程的常规方法确定了从人脐静脉内皮细胞（HUVEC）生成的 iPS 细胞的功能和表观遗传特性。四种转录因子的逆转录病毒过表达将 HUVEC 重置为多能性。人内皮细胞来源的 iPS（endo-iPS）细胞在形态、基因表达、体外和体内分化能力上与人类 ESCs 相似。endo-iPS 细胞可有效地在体外分化为内皮细胞。通过全基因组甲基化谱分析，我们表明内皮特异性基因的启动子元件在重编程后被甲基化，而多能性相关基因的启动子则被去甲基化，类似于在 ESCs 中观察到的水平。对超过 14000 个基因的功能区域中 CpG 位点的全基因组甲基化分析表明，人源性 endo-iPS 细胞与人 ES 细胞高度相似，尽管发现了 46 个基因的甲基化水平存在差异。多潜能细胞中启动子区域的总体 CpG 甲基化水平高于体细胞。我们还表明，在重编程过程中，女性人源性 endo-iPS 细胞表现出体细胞沉默的 X 染色体的重新激活。我们的研究结果表明，可以从人内皮细胞中生成 iPS 细胞，并且重编程将内皮细胞的表观遗传状态重置为多能性。
