, 2000). In the adult SVZ, the vasculature Lumacaftor research buy comprises an extensive network of planar interconnected blood vessels (Shen et al., 2008 and Tavazoie et al., 2008). Contacts between adult SVZ precursors and blood vessels are unusually permeable and frequently devoid of astrocyte and pericyte interferences, suggesting that blood-derived cues are gaining direct access to adult neural precursors and their progeny. The vasculature also provides the substrate for new neuron migration after injury in the adult striatum (Kojima et al., 2010). With endfeet surrounding

blood vessels, astrocytes form gap junctions and are closely associated with the vasculature and its basal lamina in the adult SVZ and SGZ. They may serve as an interface to modulate influences

of endothelial and circulation-derived factors as well as the availability of cytokines and growth factors in the basal lamina. In addition, astrocytes derived from neurogenic hippocampus and SVZ, but not from nonneurogenic spinal cord, promote proliferation and neuronal fate commitment of multipotent adult neural stem cells in culture (Lim and Alvarez-Buylla, 1999 and Song et al., 2002). Astrocytes express a number of secreted and membrane-attached factors both in vitro and in vivo that are known to regulate proliferation and fate specification of adult neural precursors as well as neuronal migration, maturation, and synapse formation (Barkho et al., 2006). In the adult SVZ, astrocytes express Robo receptors and regulate the rapid migration of Slit1-expressing neuroblasts through the RMS (Kaneko et al., 2010). Adult SVZ astrocytes also AZD6738 ic50 appear to release glutamate to regulate the survival of neuroblasts (Platel et al., 2010). Unique to the adult SVZ, ependymal cells lining the ventricular wall are in close association with neural precursors and their progeny, acting like a shield to protect the neurogenic niche. Ependymal cells actively regulate neuronal fate specification of adult neural precursors through Non-specific serine/threonine protein kinase release of Noggin (Lim et al., 2000). Beating of the cilia of ependymal cells appears

to set up concentration gradients of guidance molecules to direct migration of neuroblasts (Sawamoto et al., 2006). Microglia also actively regulate adult neurogenesis. Under basal conditions, apoptotic corpses of newly generated neurons are rapidly phagocytosed from the niche by unactivated microglia in the adult SGZ (Sierra et al., 2010). Under inflammatory conditions, reactivated microglia can have both beneficial and detrimental effects on different aspects of adult neurogenesis, depending on the balance between secreted molecules with pro- and anti-inflammatory action (reviewed by Ekdahl et al., 2009). In one study, the activation of microglia and recruitment of T cells were suggested to be required for enriched environment-induced SGZ neurogenesis (Ziv et al., 2006).