论文部分内容阅读
Neural stem cells (NSCs) are found in the adult brain only in specialized microenvironment or niches, mainly the subventricular zone (SVZ) of the lateral ventricle and the hippocampal dentate gyrus.The neural stem cell lineage in the SVZ includes type B cells, which express GFAP and contain the slow-dividing neural stem cells, Type C cells that are transit-amplifying cells, and type A neuroblasts which migrate anteriorly along the rostral migratory stream into the olfactory bulb.Maintenance and lineage progression of NSCs are regulated by interplays between the NSC intrinsic properties and the stem cell niche factors.We previously showed that secreted factors from endothelial cells stimulate the self-renewal of neural stem cells and enhance their neurogenic potential in vitro.Using confocal imaging analysis, we characterized the 3-D cellular architecture of the SVZ niche, showing that adult SVZ NSCs and theft progeny are bordered by the ependymal cells, which line the lateral ventricles, and blood vessels that form a plexus in the SVZ.NSCs and progenitor cells are closely apposed to the laminin-containing extracellular matrix surrounding vascular endothelial cells.Our work has identified a vascular niche in the SVZ and revealed an interaction between laminin and its receptor alpha6betal integrin which plays a functional role in binding SVZ stem cells within the vascular niche.Interestingly, apical GFAP-expressing cells are admixed in the ependymal mal layer and have contact with both the lateral ventricle and blood vessels, occupying a unique position.We have further investigated molecules and signaling pathways regulating the placement and movement of NSCs in the SVZ niche, which will help understand how stem cell niche factors affect NSC activities and adult neurogenesis.