Abstract
Cortical neural precursor cells (NPCs) sequentially undergo expansion, neurogenic and gliogenic phases during development, although the underlying mechanisms are poorly understood. We have recently shown that Wnt signaling instructively induces neuronal differentiation of NPCs. Importantly, Wnt signaling does so only in midgestation stage (neurogenic phase) of NPCs but not in early embryonic stage (expansion phase) or in perinatal stage (gliogenic phase) of NPCs. In early embryonic stage, Wnt signaling rather promotes proliferation of NPCs. Here I will discuss possible mechanisms that might account for these stage-dependent responses. Likewise, STAT3-activating ligands induce astrocytic differentiation in late (gliogenic phase) but not in early (expansion and neurogenic phases) NPCs. These stage-dependent responses of NPCs might play a central role in determining the timing of differentiation and the size of final population of each differentiated cell type. [J Physiol Sci. 2006;56 Suppl:S47]
