The central nervous system (CNS) is composed of three principal cell types: neurons, astrocytes, and oligodendrocytes. In recent years, it has become increasingly clear that glial cells are important for many of the essential functions including mediating neuronal migration and survival, controlling axonal regeneration, responding to regions of neuronal damage, controlling metabolic regulation of the blood-brain barrier, and regulation of electric stimulation. Additionally, neural stem cells in the adult brain, currently subjects of intense study due to their potential to aid in recovery from CNS injury or disease, appear to have characteristics of astrocytes in vivo.
Although, the factors involved in maintaining a niche for these neural stem cells, as well as in the activation and differentiation of these cells, are not known, it seems reasonable to expect that some of the same pathways that control glial specification may also control the differentiation state of the neural stem cells. Understanding this process at the molecular level would allow manipulation of these cells and provide prospects for future therapies aimed at inducing production of new neurons in the adult brain. The ability to regenerate functional neurons in the brain would benefit many, from victims of traumatic brain injury to sufferers of neurodegenerative diseases such as Alzheimer’s, Parkinson, and Huntington’s disease. To harness the potential of the neural stem cell, and to understand and modulate the response of the brain to injury, we must understand the molecular mechanisms underlying specification and functional integration of neurons and glia during development.