Uni-directional Neuronal Differentiation of Embryonic Stem Cells by the Neural Stem Sphere Method

Abstract

Embryonic stem (ES) cells have two characteristics, pluripotency and self-renewal. ES cells can differentiate into all other cell types, including germ cells, indicating that they may be a limitless source of functional cells for stem cell applications. We have formulated a method, the neural stem sphere (NSS) method, to efficiently obtain functional cells from these sources. The NSS method is a simple method of quickly and efficiently generating numerous neural stem cells and neurons from mouse, monkey and human ES cells. Analysis of marker gene expression during the neurogenesis of mouse ES cells induced by the NSS method demonstrated that ES cells uni-directionally differentiate into neurons via epiblasts, neuroectodermal cells and neural stem cells. This process of neuronal differentiation resembles, in part, that of neurogenesis in early embryos, suggesting that the NSS method may provide a potentially powerful tool for elucidating the mechanism underlying the efficient neural differentiation of ES cells and for assessing drugs, chemical compounds and physical stimuli that may cause neurodevelopmental impairments.