Molecular analysis of LEFTY-expressing cells in early human embryoid bodies
Molecular analysis of LEFTY-expressing cells in early human embryoid bodies
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DOI：
10.1634/stemcells.2006-0179
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发表时间：
2007-02-01
期刊：
影响因子：
5.2
通讯作者：
Benvenisty, Nissim
中科院分区：
文献类型：
--
作者：
Dvash, Tamar;Sharon, Nadav;Benvenisty, Nissim
人类 ESC (HESC) 是自我更新的多能细胞系，源自囊胚期胚胎的内细胞团。这些细胞可以产生代表三个胚胎胚层的终末分化细胞。因此，我们假设在HESC的体外分化过程中，祖细胞样细胞是短暂形成的。我们证明，已知在小鼠原肠胚形成过程中起主要作用的 LEFTY 蛋白在 HESC 分化过程中瞬时表达。此外，LEFTY蛋白似乎仅由早期人胚状体中的特定细胞群表达，该细胞群与表达ESC标记OCT4的细胞群不重叠。我们还表明，LEFTY 表达在细胞转录水平上通过 LEFTY 阳性细胞的分子标记进行调节。对 LEFTY 过表达细胞的 DNA 微阵列分析揭示了细胞表面标记物的特征，例如 CADHERIN 2 和 11。受 NODAL 控制的 LEFTY 表达似乎在中胚层起源细胞群的建立中具有重要作用，因为抑制 NODAL 活性不仅会下调 LEFTY A 和 LEFTY B 的表达，还会下调早期中胚层标记物 BRACHYURY 的表达。此外，其他中胚层谱系相关基因下调，同时外胚层相关基因上调。我们提出，在 HESC 分化的初始步骤中，中胚层祖细胞样细胞通过 NODAL 途径的激活而出现。我们的分析表明，HESC 的体外分化可以模拟人类发育的早期事件。
Human ESCs ( HESCs) are self-renewing pluripotent cell lines that are derived from the inner cell mass of blastocyst-stage embryos. These cells can produce terminally differentiated cells representing the three embryonic germ layers. We thus hypothesized that during the course of in vitro differentiation of HESCs, progenitor-like cells are transiently formed. We demonstrated that LEFTY proteins, which are known to play a major role during mouse gastrulation, are transiently expressed during HESC differentiation. Moreover, LEFTY proteins seemed to be exclusively expressed by a certain population of cells in the early human embryoid bodies that does not overlap with the population expressing the ESC marker OCT4. We also showed that LEFTY expression is regulated at the cellular transcription level by molecular labeling of LEFTY- positive cells. A DNA microarray analysis of LEFTY-overexpressing cells revealed a signature of cell surface markers such as CADHERIN 2 and 11. Expression of LEFTY controlled by NODAL appears to have a substantial role in mesodermal origin cell population establishment, since inhibition of NODAL activity downregulated expression not only of LEFTY A and LEFTY B but also of BRACHYURY, an early mesodermal marker. In addition, other mesodermal lineage-related genes were downregulated, and this was accompanied by an upregulation in ectoderm-related genes. We propose that during the initial step of HESC differentiation, mesoderm progenitor-like cells appear via activation of the NODAL pathway. Our analysis suggests that in vitro differentiation of HESCs can model early events in human development.