Heterogeneity of quiescent and active neural stem cells in the postnatal brain

Abstract

In the postnatal mammalian brain, neurogenic activity is retained in anatomically restricted areas, driven by pools of Neural Stem Cells (NSCs). These cells and their progeny have been studied intensively as potential targets for regenerative treatments, aiming either to their in situ manipulation, or to their use as sources of cells for transplantation-based strategies. Although their full identity, heterogeneity and differentiation potential remain elusive, due to the absence of specific cell-type markers, our knowledge on their properties is constantly expanding. Here, we focus on the NSC niche that is located at the Subependymal Zone (SEZ/ also known as Subventricular Zone) of the lateral ventricles of the brain. We review, summarize and explain the different faces of the NSC, as they have been described using a wide range of experimental approaches in a time-frame of three decades: the primitive, definitive, quiescent or activated NSC. We also review the accumulating evidence on the existence of latent NSCs outside of niches, in the brain parenchyma, that constitute new promising therapeutic targets, complemented by the novel technologies of in vivo cell reprogramming.

Constitutive cell proliferation and neurogenesis in the organum vasculosum lamina terminalis and subfornical organ of adult rats

“…Since SFO tanycytes express the NSC marker Sox2 (Figure 3B), but do not undergo constitutive proliferation, they might represent a quiescent NSC pool. Previous studies in the SVZ and SGZ have demonstrated that NSC pools remain dormant until they are stimulated, inducing the quiescent NSCs to enter the cell cycle and start proliferating 56–58 . Injuries and pathological states can induce the transition of quiescent NSCs into proliferating NSCs 59–61 .…”

“…Previous studies in the SVZ and SGZ have demonstrated that NSC pools remain dormant until they are stimulated, inducing the quiescent NSCs to enter the cell cycle and start proliferating. [56][57][58] Injuries and pathological states can induce the transition of quiescent NSCs into proliferating NSCs. [59][60][61] Future studies should elucidate if SFO tanycytes represent a quiescent NSC pool that can be stimulated and proliferate, generating new neurons and glia in physiological or pathological conditions.…”

A Reversible Neural Stem Cell Quiescence and Activation Culture System for Metabolic Study

“…However, these models frequently involve cells from different cell lines, potentially introducing unwanted variations and/or unknown confounding factors. Activated and quiescent NSCs represent distinct states of the same cells, thus minimizing unwanted variations and mitigating unknown confounding factors 12 , 13 . Therefore, we sought to establish a reversible activation and quiescence culture system and expect this system should serve as a powerful platform for dissecting cell metabolism and its dynamics.…”