A pathophysiological view of the neural stem cell niche

Abstract

Neural stem cells were described in the nervous system some decades ago as being responsible for adult neurogenesis and hence the structural plasticity in the tissue. These cells reside in specialized niches where they are exposed to paracrine signaling regulating their behavior. The discovery opened new perspectives for nervous system regeneration and repair, which will be greatly improved, as we know more about the molecular mechanisms taking place within the stem cell niche. Recent data enhance our understanding of the functioning of an adult neural stem cell niche. We now know that there are important cellular elements such as vascular and neuronal cells, as well as critical non-cellular elements such as the low levels of oxygen, regulating the biology of the progenitors. Studies about adult neural stem cells and their niche might also be important to understand the pathology of brain cancer. It has been reported that brain tumors rely on a group of deregulated stem cells, the so termed cancer stem cells, or tumor initiating cells. Interestingly, recent evidence suggests the possibility that these malignant cells depend on the formation of an aberrant cancer stem cell niche that would allow them to proliferate and drive tumor growth. Furthermore, it seems like again this type of aberrant niche is composed of cellular elements like vascular cells, and non-cellular elements like an aggressive hypoxia driving a grossly disorganized angiogenesis and the proliferation of tumor stem cells. A detailed understanding of the molecular interplays taking place in the tumor niche will greatly improve our capacity to efficiently treat this disease and specifically kill the tumor initiating cells to avoid relapse. In this chapter, we will expose our actual knowledge about the functioning of normal and pathological stem cell niches in the adult nervous system, discussing the therapeutic implications this knowledge might have on the treatment of this devastating disease. © 2011 by Nova Science Publishers, Inc. All rights reserved.