Glial Cells in Health and Disease of the CNS

Jaime Eugenín-von Bernhardi, Leda Dimou, Eugenín-von Bernhardi, Jaime, Dimou, Leda

NG2-glia are a mysterious and ubiquitous glial population with a highly branched morphology. Initial studies suggested that their unique function is the generation and maintenance of oligodendrocytes in the central nervous system (CNS), important for proper myelination and therefore for axonal support and fast conduction velocity. Over the last years this simplistic notion has been dramatically changed: the wide and homogeneous distribution of NG2-glia within all areas of the developing CNS that is maintained during the whole lifespan, their potential to also differentiate into other cell types in a spatiotemporal manner, their active capability of maintaining their population and their dynamic behavior in altered conditions have raised the question: are NG2-glia simple progenitor cells or do they play further major roles in the normal function of the CNS? In this chapter, we will discuss some important features of NG2-glia like their homeostatic distribution in the CNS and their potential to differentiate into diverse cell types. Additionally, we will give some further insights into the properties that these cells have, like the ability to form synapses with neurons and their plastic behavior triggered by neuronal activity, suggesting that they may play a role specifically in myelin and more generally in brain plasticity. Finally, we will briefly review their behavior in disease models suggesting that their function is extended to repair the brain after insult.