Radial glial cells, are a pivotal cell type in the developing central nervous system (CNS) involved in key developmental processes, from patterning and neuronal migration to their recently discovered role as precursors during neurogenesis.[1][2] They arise early in development from neuroepithelial cells. Radial phenotype is typically transient, but some cells, such as Bergmann glia in the cerebellum and Muller glia in the retina, retain radial glia-like morphology postnatally. According to recent reseach, during the late stages of cortical development, radial glial cells divide asymmetrically in the ventricular zone to generate radial glial cells and intermediate progenitor cells and after that intermediate progenitor cells divide symmetrically in the subventricular zone to produce multiple neurons.[3]
The term 'radial glial cell' refers to their two major characteristics, their long radial processes extending from the ventricular zone (VZ) to the pial surface and their glial properties, such as the content of glycogen granules or the expression of the astrocyte-specific glutamate transporter or the glial fibrillary acidic protein (GFAP). Another radial glia-specific protein is the brain lipid binding protein (FABP7), expression of which could be induced by Notch-1 activation,[4] in particular, when acted upon by reelin.[5] Interestingliy, Notch 1, then activated before birth, induces radial glia differentiation,[6] but postnatally induces the differentiation into astrocytes.[7]
Studies show that radial glial cells characterized by long radial processes and astroglial properties constitute the majority of precursors during neurogenesis. Indeed, all radial glial cells divide throughout neurogenesis and give rise to the majority of projection neurons in the cerebral cortex.
^ Martínez-Cerdeño V, Noctor SC, Kriegstein AR. The role of intermediate progenitor cells in the evolutionary expansion of the cerebral cortex. Cereb Cortex. 2006 Jul;16 Suppl 1:i152-61. PMID 16766701
