How neural stem cells contribute to neocortex development

Abstract

The mammalian neocortex is the seat of higher cognitive functions, such as thinking and language in human. A hallmark of the neocortex are the cortical neurons, which are generated from divisions of neural progenitor cells (NPCs) during development, and which constitute a key feature of the well-organized layered structure of the neocortex. Proper formation of neocortex structure requires an orchestrated cellular behavior of different cortical NPCs during development, especially during the process of cortical neurogenesis. Here, we review the great diversity of NPCs and their contribution to the development of the neocortex. First, we review the categorization of NPCs into different classes and types based on their cell biological features, and discuss recent advances in characterizing marker expression and cell polarity features in the different types of NPCs. Second, we review the different modes of cell divisions that NPCs undergo and discuss the importance of the balance between proliferation and differentiation of NPCs in neocortical development. Third, we review the different proliferative capacities among different NPC types and among the same type of NPC in different mammalian species. Dissecting the differences between NPC types and differences among mammalian species is beneficial to further understand the development and the evolutionary expansion of the neocortex and may open up new therapeutic avenues for neurodevelopmental and psychiatric disorders.

Water-Soluble, Alanine-Modified Fullerene C60 Promotes the Proliferation and Neuronal Differentiation of Neural Stem Cells

“…Symmetric cell divisions of NSCs generate two daughter cells sharing the same identity, which is also the same as that of the mother cell. In asymmetric self-renewing cell division, the two daughter cells generated from an NSC have different identities, but one of them shares the same identity as that of the mother cell [ 40 ]. In addition, NSCs can differentiate into lineage-specific cells, such as neurons, oligodendrocytes, and astrocytes [ 41 ].…”

Evolution of the Neocortex Through RNA-Binding Proteins and Post-transcriptional Regulation

“…aRG can either self-renew through a series of proliferative symmetric divisions, or divide asymmetrically in a proliferative and consumptive manner. Asymmetric proliferative division generates one daughter cell that is identical to its mother aRG, and another daughter cell that is either an immature postmitotic neuron ( direct neurogenesis ), or one of the two main types of more committed BPs: (1) transit-amplifying progenitors or intermediate progenitor cells (IPCs), or (2) outer radial glial cells or basal radial glia (bRG) ( indirect neurogenesis ) ( Kriegstein et al, 2006 ; Lui et al, 2011 ; Xing et al, 2021 ). As a result of this enormous accumulation of BP, the neocortex becomes even thicker and is comprised of distinct developmental regions: the VZ, the subventricular zone (SVZ), the intermediate zone (IZ), the subplate (SP), the cortical plate (CP), and the marginal zone (MZ).…”

“…In the small-brained lissencephalic mammals (e.g., rodents), IPC are the most abundant population of BP in the SVZ with restricted mitotic capacity as they typically undergo one terminal symmetric consumptive division to give rise to two immature neurons ( Haubensak et al, 2004 ; Miyata et al, 2004 ; Xing et al, 2021 ). The remaining rare population of rodent BP belongs to bRG, which are localized more toward the upper region of the still undifferentiated SVZ ( Wang et al, 2011 ; Vaid et al, 2018 ).…”

“…The iSVZ of gyrencephalic mammals is composed mostly of the IPC population during neurogenesis, and it is comparable in its thickness to the still undifferentiated SVZ of the lissencephalic mammal. However, the primate oSVZ is the largest proliferative compartment due to the presence of highly proliferative and neurogenic bRG, which tend to use the available area of the thickening SVZ for symmetric proliferative (two daughter bRG) or asymmetric proliferative divisions (one daughter bRG with self-renewal capacity, and another daughter IPC or neuron) ( Smart, 2002 ; Kriegstein et al, 2006 ; Fietz et al, 2010 ; Silbereis et al, 2016 ; Xing et al, 2021 ). While the cell cycle kinetics of the lissencephalic progenitors generally decrease overtime ( Takahashi et al, 1995 ), the peak expansion of superficial-layer neurons occurs during the later stages of primate neurogenesis in tandem with the upsurge of bRG proliferation ( Figure 11 ), as well as the transformation of aRG into more truncated morphologies.…”

“…The prenatal neurogenesis is finalized once aRG and BP begin symmetric or asymmetric consumptative divisions, giving rise to postmitotic neurons. The progenitors then shift to gliogenesis, which is a process that completely depletes the progenitor pool by generating astrocytes and oligodendrocytes ( Xing et al, 2021 ).…”