Neural Progenitors

Neural progenitors are unspecialized stem cells located in the central nervous system (CNS). They are capable of self-renewal and have the capacity to produce a larger variety of progeny, such as neurons, astrocytes, and oligodendrocytes. As such, they are important for normal neurogenesis throughout the lifespan of an organism. Additionally, they play an integral role in diseases and injury-associated neurogenesis, and therefore may be promising targets for therapeutic intervention. Neural progenitors are found in the adult mammalian brain, where they are particularly abundant in the ventricular zone (VZ). The VZ consists of a layer of proliferative neural stem cells lining the lateral ventricles of the brain. In the adult human brain, neural progenitors are rarely found outside of the VZ and, when present, contribute to neurogenesis in different ways. In the subventricular zone (SVZ) of the adult human forebrain, for example, neural progenitors form transit amplifying progenitors, which actively produce a large number of neuron precursors. In the adult mouse brain, the subgranular zone (SGZ) of the hippocampus is populated by neural progenitors which act as a pool of progenitors for neurogenesis in the dentate gyrus. Neural progenitors show distinct behaviors in different brain regions. Adult mammalian VZ neural progenitors are highly quiescent, with very slow turnover and low levels of proliferation. In contrast, SVZ and SGZ neural progenitors demonstrate highly dynamic properties, rapidly producing more differentiated progeny such as mature neurons. These specific behaviors of neural progenitors are likely due to the regional microenvironment in which they exist, as various factors may either promote or repress progenitor proliferation and differentiation. Altogether, neural progenitors are important, yet highly understudied, cells found within the adult mammalian brain. Their crucial role in maintaining the delicate balance of neurogenesis across the lifespan and in diseases and injury associated neurogenesis further emphasize their significance. Elucidating the regional differences in neural progenitor behavior will be key in further advancing our understanding of adult brain plasticity and regeneration.