Differentiation Mechanism of Embryonic Stem Cells into Neural Stem Cells

点击翻译按钮获取中文摘要

Neural stem cells differentiate from embryonic stem (ES) cells via formation of neural stem spheres (NSSs) under free-floating conditions in astrocyte-conditioned medium (ACM). During subsequent culture of the NSSs on an adhesive substrate with fibroblast growth factor (FGF)-2, the neural stem cells are induced to migrate onto the substrate, resulting in an expansion of the cell number. Furthermore, almost all these cells can be differentiated into functional neurons by changing the medium from Neurobasal B-27 to ACM, suggesting that differentiation of the ES-cell-derived neural stem cells into neurons requires some instructive factors present in ACM. In addition, these ES-cell-derived neural stem cells can be differentiated almost exclusively into astrocytes by withdrawing FGF-2 from the medium without any additional humoral factors. This astrocytegenesis does not require any additional instructions in contrast to neurogenesis. Our results indicate that differentiation along the astrocyte lineage is a default state of ES-cell-derived neural stem cells