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Abstract：
During neurogenesis, neural patterning is a critical step during which neural progenitor cells differentiate into neurons with distinct functions. However, the molecular determinants that regulate neural patterning remain poorly understood. Here we optimized the \"dual SMAD inhibition\" method to specifically promote differentiation of human pluripotent stem cells (hPSCs) into forebrain and hindbrain neural progenitor cells along the rostral-caudal axis. We report that neural patterning determination occurs at the very early stage in this differentiation. Undifferentiated hPSCs expressed basal levels of the transcription factor orthodenticle homeobox 2 (OTX2) that dominantly drove hPSCs into the \"default\" rostral fate at the beginning of differentiation. Inhibition of glycogen synthase kinase 3β (GSK3β) through CHIR99021 application sustained transient expression of the transcription factor NANOG at early differentiation stages through Wnt signaling. Wnt signaling and NANOG antagonized OTX2 and, in the later stages of differentiation, switched the default rostral cell fate to the caudal one. Our findings have uncovered a mutual antagonism between NANOG and OTX2 underlying cell fate decisions during neural patterning, critical for the regulation of early neural development in humans.
摘要：
在神经发生期间，神经模式是神经祖细胞分化为具有不同功能的神经元的关键步骤。然而,调节神经模式的分子决定因素仍然知之甚少。在这里，我们优化了“双重SMAD抑制”方法，以特异性促进人多能干细胞（hPSC）沿着头尾轴分化为前脑和后脑神经祖细胞。我们报告说，神经模式的确定发生在这种分化的早期阶段。未分化的hPSC表达转录因子同源盒2（OTX2）的基础水平，该水平在分化开始时主要驱使hPSC进入“默认”结局。通过CHIR99021应用抑制糖原合成酶激酶3β(GSK3β)在早期分化阶段通过Wnt信号传导维持转录因子NANOG的瞬时表达。Wnt信号和NANOG拮抗OTX2，在分化的后期，将默认的延髓细胞命运切换到尾端细胞命运。我们的发现揭示了神经模式过程中NANOG和OTX2潜在细胞命运决定之间的相互拮抗作用。对人类早期神经发育的调控至关重要。
