Cellular Niches for Endogenous Neural Stem Cells in the Adult Brain

Neural stem cells are present throughout life and continuously give rise to new neurons and glia cells in the mammalian central nervous system. Accumulating evidence suggests essential roles of micro-environments, or niches, in supporting active neurogenesis from endogenous neural stem cells within restricted regions of the adult brain. These neurogenic niches also regulate different steps of adult neurogenesis in response to physiological and pathological stimulations. Recent studies have identified several cellular niche components, including endothelial cells, astroglia, ependymal cells, immature progeny of NSCs and mature neurons. In this review, we discuss identified niche signals from these cellular components in regulating different steps of adult neurogenesis. We also highlight some of the potential therapeutic targets to be manipulated within neurogenic niche for repair of the adult central nervous system.