NANOG-OCT4-SOX2 Regulatory Module in Human Embryonic Stem Cells (dataset 2)

The transcription factors Nanog, Oct4 and Sox2 are the master regulators of pluripotency in mouse embryonic stem cells (mESCs), however, their functions in human ESCs (hESCs) have not been rigorously defined. Here we show that the requirements for NANOG, OCT4 and SOX2 in hESCs differ from those in mESCs. Both NANOG and OCT4 are required for self-renewal and repress differentiation. OCT4 controls both extraembryonic and epiblast-derived cell fates in a BMP4-dependent manner. OCT4-depleted hESCs commit to trophectoderm and primitive endoderm in the presence of BMP4, but undergo neuroectoderm differentiation in the absence of BMP4. NANOG represses neuroectoderm and neural crest commitment, but has little or no effect on the other lineages. We find that SOX2 is not required for self-renewal because it is redundant with SOX3, which is induced in SOX2-depleted hESCs. Simultaneous depletion of both SOX2 and SOX3 induces differentiation into the primitive streak. Unexpectedly, we identify significant variability in the usage of pluripotency factors by individual hESC lines, suggesting that the pluripotency network is remodelled to support a continuum of developmental states. Our study revises the general view of how NANOG, OCT4 and SOX2 orchestrate self-renewal in hESCs. Total RNA obtained from hESCs with or without BMP4 treatment for 8 days time course.

转录因子Nanog、Oct4与Sox2是小鼠胚胎干细胞（mouse embryonic stem cells, mESCs）多能性的核心调控因子，然而其在人类胚胎干细胞（human embryonic stem cells, hESCs）中的功能尚未得到严谨界定。本研究证实，hESCs中NANOG、OCT4及SOX2的功能需求与mESCs存在显著差异。NANOG与OCT4均为hESCs自我更新所必需，且可抑制细胞分化。OCT4以骨形态发生蛋白4（BMP4）依赖的方式调控胚外及上胚层来源的细胞命运：OCT4沉默的hESCs在BMP4存在时会定向分化为滋养外胚层与原始内胚层，而在无BMP4的培养条件下则会发生神经外胚层分化。NANOG可抑制神经外胚层与神经嵴的定向分化，但对其他细胞谱系几乎无调控作用。本研究发现，SOX2并非hESCs自我更新所必需，因为其功能可由SOX3代偿——SOX3会在SOX2沉默的hESCs中被诱导表达。同时沉默SOX2与SOX3则会诱导细胞向原条方向分化。出乎意料的是，本研究发现不同hESC细胞系对多能性因子的使用模式存在显著差异，这提示多能性调控网络发生了重塑，以支持一系列连续的发育状态。本研究修正了学界关于NANOG、OCT4及Sox2如何协同调控hESCs自我更新的普遍认知。本次研究的数据集来源于经或未接受BMP4处理、覆盖8天时间进程的hESCs总RNA。