Radial glia

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. cite journal |author=Campbell K, Götz M |title=Radial glia: multi-purpose cells for vertebrate brain development |journal=Trends Neurosci. |volume=25 |issue=5 |pages=235–8 |year=2002 |month=May |pmid=11972958 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0166223602021562] cite journal |author=Merkle FT, Tramontin AD, García-Verdugo JM, Alvarez-Buylla A |title=Radial glia give rise to adult neural stem cells in the subventricular zone |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=101 |issue=50 |pages=17528–32 |year=2004 |month=December |pmid=15574494 |pmc=536036 |doi=10.1073/pnas.0407893101 |url=http://www.pnas.org/cgi/pmidlookup?view=long&pmid=15574494] 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 research, 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. 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]

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, cite journal |author=Anthony TE, Mason HA, Gridley T, Fishell G, Heintz N |title=Brain lipid-binding protein is a direct target of Notch signaling in radial glial cells |journal=Genes Dev. |volume=19 |issue=9 |pages=1028–33 |year=2005 |month=May |pmid=15879553 |pmc=1091737 |doi=10.1101/gad.1302105 |url=http://www.genesdev.org/cgi/pmidlookup?view=long&pmid=15879553] in particular, when acted upon by reelin. cite journal |author=Keilani S, Sugaya K |title=Reelin induces a radial glial phenotype in human neural progenitor cells by activation of Notch-1 |journal=BMC Dev. Biol. |volume=8 |issue=1 |pages=69 |year=2008 |month=July |pmid=18593473 |doi=10.1186/1471-213X-8-69 |url=http://www.biomedcentral.com/1471-213X/8/69] Interestingliy, Notch 1, then activated before birth, induces radial glia differentiation, cite journal |author=Gaiano N, Nye JS, Fishell G |title=Radial glial identity is promoted by Notch1 signaling in the murine forebrain |journal=Neuron |volume=26 |issue=2 |pages=395–404 |year=2000 |month=May |pmid=10839358 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0896-6273(00)81172-1] but postnatally induces the differentiation into astrocytes. cite journal |author=Chambers CB, Peng Y, Nguyen H, Gaiano N, Fishell G, Nye JS |title=Spatiotemporal selectivity of response to Notch1 signals in mammalian forebrain precursors |journal=Development |volume=128 |issue=5 |pages=689–702 |year=2001 |month=March |pmid=11171394 |doi= |url=http://dev.biologists.org/cgi/pmidlookup?view=long&pmid=11171394]

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.

Expression of the PAX6, a transcription factor, was found to be the key feature of neurogenic radial glia. cite journal |author=Götz M, Stoykova A, Gruss P |title=Pax6 controls radial glia differentiation in the cerebral cortex |journal=Neuron |volume=21 |issue=5 |pages=1031–44 |year=1998 |month=November |pmid=9856459 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0896-6273(00)80621-2] cite journal |author=Mo Z, Zecevic N |title=Is Pax6 critical for neurogenesis in the human fetal brain? |journal=Cereb. Cortex |volume=18 |issue=6 |pages=1455–65 |year=2008 |month=June |pmid=17947347 |doi=10.1093/cercor/bhm181 |url=http://cercor.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17947347]

See also

* Glia
* Bergmann glia
* Muller glia

ources

* Hartfuss E, Forster E, Bock HH, Hack MA, Leprince P, Luque JM, Herz J, Frotscher M, Gotz M. (2003) Reelin signaling directly affects radial glia morphology and biochemical maturation. Development 130(19):4597-609. PMID 12925587

References