Biology and pathology of glia: an update

Excerpt

We have known for decades that astrocytes are the “supportive” components in neural tissue, oligodendrocytes elaborate myelin sheaths, microglia are phagocytes, the choroid plexus produces the cerebrospinal fluid (CSF), and ependymal cells guarantee CSF flow by keeping the aqueduct open. While this extremely simplified assignment of activities is still valid today and helpful in explaining the brain to the uninitiated, the roles of different glial cell types in the brain have turned out as manifold and complex. A variety of unexpected functions have been recently proposed, such as for ependymal cells in stem cell based cell renewal, for microglia serving as a primary target in neurodegeneration, and for choroid plexus in multiple sclerosis. A steadily increasing number of studies have demonstrated extremely diverse functions of glia, and it is fair to say that there is virtually no neurological disease where glia does not play a role in pathogenesis. …