How a Radial Glial Cell Decides to Become a Multiciliated Ependymal Cell

The V-SVZ adult neurogenic niche is located in the wall of the lateral ventricles and contains neural stem cells, with self-renewing and differentiating ability and postmitotic multiciliated ependymal cells, an important structural and trophic component of the niche. The niche is established at postnatal stages from a subpopulation of radial glial cells, determined during embryogenesis. Radial glial cells constitute a heterogeneous population, which give rise, in addition to niche cellular components, to neurons and glial cells. The mechanisms that direct their fate commitment towards V-SVZ niche cells are largely unknown. In the present review, we discuss recent findings on the signaling networks governing fate commitment decisions of radial glial cells towards multiciliated ependymal cells. We highlight the role of two novel factors: McIdas and GemC1/Lynkeas and the molecular pathways which they activate in order to promote ependymal cell differentiation. Finally, we discuss a possible crosstalk of known signaling pathways, such as Notch, STAT3, and BMPs, for the specification of ependymal versus adult neural stem cells in the V-SVZ niche.