Cell and Tissue Research

, Volume 331, Issue 1, pp 179–191

Cells in the astroglial lineage are neural stem cells

Review

Abstract

A common assumption of classical neuroscience was that neurons and glial cells were derived from separate pools of progenitor cells and that, once development was completed, no new neurons were produced. The subsequent disproving of the “no new neuron” dogma suggested that ongoing adult neurogenesis was supported by a population of multipotent neural stem cells. Two germinal regions within the adult mammalian brain were shown to contain neural progenitor cells: the subventricular zone (SVZ) along the walls of the lateral ventricles, and the subgranular zone (SGZ) within the dentate gyrus of the hippocampus. Surprisingly, when the primary progenitors (stem cells) of the new neurons in these regions were identified, they exhibited structural and biological markers of astrocytes. The architecture of these germinal regions and the pattern of division of neural stem cells have raised fundamental questions about the mechanism of adult neurogenesis. This review describes studies on the origin of adult neural stem cells, the features distinguishing them from astrocytes in non-germinal regions, and the control mechanisms of the proliferation and differentiation of these cells. Astrocytic adult neural stem cells are part of a developmental lineage extending from the neuroepithelium to radial glia to germinal astrocytes. Adult neural stem cells appear to be strongly influenced by their local microenvironment, while also contributing significantly to the architecture of these germinal zones. However, environment alone does not seem to be sufficient to induce non-germinal astrocytes to behave as neural stem cells. Although emerging evidence suggests that significant heterogeneity exists within populations of germinal zone astrocytes, the way that these differences are encoded remains unclear. The further characterization of these cells should eventually provide a body of knowledge central to the understanding of brain development and disease.

Keywords

Neural stem cells Radial astrocytes Intermediate progenitors Radial glia Subventricular zone Subgranular zone Tumor stem cells 

Abbreviations

Ara-C

cytosine-β-D-arabinofuranoside

BMP

bone morphogenetic protein

BrdU

bromodeoxyuridine

CNS

central nervous system

EGF

epidermal growth factor

EGFR

EGF receptor

FGF

fibroblast growth factor

GFAP

glial fibrillary acidic protein

HSV-TK

Herpes simplex virus thymidine kinase

LGE

lateral ganglionic eminence

PGC

periglomerular cell

PDGF

platelet-derived growth factor

PDGFRα

PDGF receptor alpha

RMS

rostral migratory stream

SGZ

subgranular zone

SVZ

subventricular zone

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Department of Neurosurgery and Institute for Regeneration MedicineUniversity of California at San FranciscoSan FranciscoUSA

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