Human embryonic stem cells derived from embryos at different stages of development share similar transcription profiles

We have derived hESC from biopsied blastomeres of cleavage stage embryos under virtually the same conditions we used for the derivation of hESC lines from inner cell mass of blastocyst stage embryos. Blastomere-derived hESC lines exhibited all the standard characteristics of hESC including undifferentiated proliferation, genomic stability, expression of pluripotency markers and the ability to differentiate into the cells of all three germ layers both in vitro and in vivo. To examine whether hESC lines derived from two developmental stages of the embryo differ in gene expression, we have subjected three blastomere-derived hESC lines and two ICM-derived hESC lines grown under identical culture conditions to transcriptome analysis using gene expression arrays. Unlike previously reported comparisons of hESC lines which demonstrated, apart from core hESC-associated pluripotency signature, significant variations in gene expression profiles of different lines, our data show that hESC lines derived and grown under well-controlled defined culture conditions adopt nearly identical gene expression profiles. Moreover, blastomere-derived and ICM-derived hESC exhibited very similar transcriptional profiles independent of the developmental stage of the embryo from which they originated. Furthermore, this profile was evident in very early passages of the cells and did not appear to be affected by extensive passaging. These results suggest that during derivation process cells which give rise to hESC acquire virtually identical stable phenotype and are not affected by the developmental stage of the starting cell population. we investigated whether human stem cell lines derived from late totipotent blastomeres of the cleavage stage embryo develop a more “primitive” phenotype than ICM-derived lines by profiling their respective gene expression, molecular regulation and signaling pathways. In this study, we examined whether the inherent differences in the development stage of the starting embryonic cell population are maintained in the derived hESC lines by evaluating the stemness, differentiation capacity and gene expression profiles of blastomere- and ICM-derived hESC lines.

我们在与从囊胚期胚胎内细胞团（inner cell mass, ICM）建立人类胚胎干细胞（human embryonic stem cell, hESC）系完全一致的条件下，从卵裂期胚胎的活检卵裂球中分离培养得到了hESC。卵裂球来源的hESC系具备hESC的所有标准特征，包括未分化增殖能力、基因组稳定性、多能性标志物表达，以及可在体外（in vitro）和体内（in vivo）分化为三胚层细胞的潜能。为探究源自胚胎两个不同发育阶段的hESC系在基因表达上是否存在差异，我们对在相同培养条件下培养的3株卵裂球来源hESC系与2株ICM来源hESC系采用基因表达芯片开展转录组分析。与既往报道的hESC系对比研究结果不同——既往研究显示，除核心hESC相关多能性特征标签外，不同hESC系的基因表达谱存在显著差异——本研究数据表明，在严格可控的限定培养条件下建立并培养的hESC系，其基因表达谱几乎完全一致。此外，无论源自胚胎的发育阶段如何，卵裂球来源与ICM来源的hESC均表现出高度相似的转录谱。进一步而言，这种表达谱在细胞极早期传代时即已显现，且未受多次传代的影响。上述结果表明，在hESC建立过程中，起始细胞会获得几乎完全一致的稳定表型，且不受其初始细胞群发育阶段的影响。我们进一步通过分析各自的基因表达、分子调控及信号通路，探究了源自卵裂期胚胎晚期全能卵裂球的人类干细胞系是否比ICM来源的细胞系呈现出更具"原始性"的表型。本研究还通过评估卵裂球来源与ICM来源hESC系的干细胞干性、分化能力及基因表达谱，探究了起始胚胎细胞群发育阶段的固有差异是否会在所建立的hESC系中得以保留。