In Vitro Models for Neurogenesis

Abstract

The process of generating new neurons of different phenotype and function from undifferentiated stem and progenitor cells starts at very early stages of development and continues in discrete regions of the mammalian nervous system throughout life. Understanding mechanisms underlying neuronal cell development, biology, function, and interaction with other cells, especially in the neurogenic niche of fully developed adults, is important in defining and developing new therapeutic regimes in regenerative neuroscience. Studying these complex and dynamic processes in vivo is challenging because of the complexity of the nervous system and the presence of many known and unknown confounding variables. However, the challenges could be overcome with simple and robust in vitro models that more or less recapitulate the in vivo events. In this work, we will present an overview of present available in vitro cell-based models of neurogenesis.

Figure 1.

The NeuroBlast assay (NBA) culture as an in vitro neurogenesis model. (A) (1) Monolayer culture of differentiatng neural stem cells on day 4 after plating. As evident, the culture contains a layer flat astrocytic like cells underneath and scattered round cells on top (in red rectangle). (2) 24 h after switching the culture medium to growth-factor-free medium, that is, day 6 after the initial plating, the top round cells rapidly divide and generate colonies of immature neuroblasts. (3) As the culture reaches day 8 from the initial plating, size of the neuroblast colonies increase owing to continuous proliferation of the neuroblast cells. (B,C) Immunofluorescent staining of representative NBA cultures on day 8 showing glial fibrillary acidic protein (GFAP)-expressing astrocytic cells (green) underneath a few colonies of closely packed neuroblasts expressing βIII tubulin (red) and also O4-expressing oligodendrocytic cells (red) dispersed among the GFAP-expressing astrocytic cells (green). DAPI, 4′,6-diamidino-2-phenylindole. Scale bar, 50 µm.