NeuroCore formation during differentiation of neurospheres of mouse embryonic neural stem cells.

Neural stem cells (NSCs) in the embryonic neocortex have the potential to generate a well-organized laminar architecture of the cerebral cortex through precise regulation of the proliferation, differentiation, and migration of neural cells. NSCs can be isolated in vitro and expanded as cell clusters, called neurospheres, which are primarily related to the proliferation ability of NSCs. Conversely, the tissue-organizing properties of NSCs via regulated differentiation and migration of the cells are not well understood. In this study, we established a three-dimensional (3D) differentiation model of neurospheres, which produce unique neuronal clusters, termed NeuroCore (NC). NC formation was initiated by the aggregation of young neurons. Upon maturation of the neurons and the establishment of radial glia-like structures, the initial organization of the NCs transformed into a glomeruli-like arrangement of cortical neurons. These neurons expressed multiple markers of upper and deep cortical neurons. Taken together, we propose that NSCs in vitro maintain some aspects of their original in vivo tissue-organizing properties, providing an alternative opportunity to explore the fundamental components of brain histogenesis in vitro.