The extracellular matrix compartment of neural stem and glial progenitor cells.

Neuroepithelial and radial GLIA stem cells generate the majority of the cellular constituents of the central nervous system. Following precisely timed phases of neurogenesis and gliogenesis the stem cells recede, with the exception of adult neural stem cells that persist in two generally accepted canonical neurogenic regions, the subventricular zone of the lateral ventricle and the subgranular zone in the dentate gyrus of the hippocampus. It is believed that adult stem cells reside in privileged stem cell niche environments that provide favorable conditions for self-renewal and maintenance of this cellular compartment. Factors such as morphogens, cytokines, and growth factors influence the developmental pathway of neural stem/progenitor cells. By comparison, less is known about the regulatory roles of glycoproteins and proteoglycans of the extracellular matrix (ECM) and their receptors, although they represent important constituents of the micromolecular environment of the niche. Here, we summarize studies that indicate pivotal roles of the ECM micromilieu for the biology and instrumental use of glial stem and progenitor cells of the CNS. Advancing our understanding of structure-function relationships, signaling motifs and complementary receptors and their signal transduction pathways will be of central importance for the application of these cell types in regenerative medicine.