[Glial cells function as neural stem cells and progenitor cells]

Abstract

Glial cells, including astrocytes, oligodendrocyte progenitor cells (OPCs), NG2-glia, etc, are broadly distributed throughout the central nervous system (CNS). Also, it has been well known that glial cells play multi-roles in physiological and pathological processes in the CNS, such as maintaining homeostasis, providing neurotrophins for neurons and regulating neural signal transmission. Recently, increasing evidence showed that glial cells may also function as neural stem/progenitor cells and contribute to adult neurogenesis or neuroregeneration. In pathological conditions, for instance, astrocytes and OPCs could be activated to proliferate and differentiate. When cultured in vitro, they could form neurospheres which possess the ability to differentiate into astrocytes, oligodendrocytes and neurons. Additionally, forced expression of exogenous genes in astrocytes and NG2-glia can successfully reprogram them into neurons, which may also be suggestive of their stem/progenitor cell features. Here, we review current knowledge of the stem cell-like properties of glial cells, including what types of glial cells can function as stem/progenitor cells, how they can acquire the stem/progenitor potential and what progenies can be produced. These insights may foster a better understanding of glial cell biology and function in physiological or pathological processes in the CNS and lead to the idea of using the stem/progenitor-like glial cells as endogenous cell source for neural repair.