Molecular control of adult neurogenesis in the human subependymal zone
Adult neurogenesis
The generation of new functional neurons from multipotent neural stem cells, termed neurogenesis, has been shown to persist in many mammalian species in two regions of the adult brain: the subgranular zone of the hippocampal dentate gyrus and the subependymal zone [SEZ, also subventricular zone] adjacent to the lateral ventricles [1, 2]. Lower levels of neurogenesis have been reported in other regions of the rodent and primate brain, including the neocortex [3, 4], amygdala [5] and substantia nigra [6], but this has been difficult to replicate consistently other than in the diseased brain [7]. Other studies provided compelling evidence that precursor …show more content…
Adult neurogenesis in the subependymal zone
In the human brain, the adult SEZ is a four-layered structure, with a monolayer of ependymal cells (layer I), a hypocellular gap (layer II), an astrocytic ribbon of cells composed of astrocytes (layer III), and a transitory zone (layer IV) [11, 12]. Neural stem cells with astrocyte-like properties (type B cells) reside in the astrocytic ribbon and typically express glutamate-aspartate transporter, nestin and the δ-isoform of glial fibrillary acidic protein (Figure 1) [13-15]. These type B cells need to re-enter the cell cycle in order to generate transit amplifying progenitor cells (type C cells), which in turn produce neuroblasts …show more content…
Ependymal cells that face the lateral ventricles, are coverd by cilia and microvilli, and represent critical regulators of stem cell self-renewal and neuronal determination by releasing neurogenic factors, such as noggin, which inhibits gliogenesis and promotes neurogenesis [27], and the pigment epithelium-derived factor, which participates in the maintenance of neural precursor cells [28]. Neurogenic niches are closely located to the vasculature [29, 30], where endothelial cells provide an important promotor of adult neurogenesis, the vascular endothelial growth factors [31, 32]. Microglia have been detected in both neurogenic regions in the adult brain, and experimental evidence indicates that they can be either detrimental or supportive for adult neurogenesis depending on their state of activation and functional phenotype
Adult neurogenesis
The generation of new functional neurons from multipotent neural stem cells, termed neurogenesis, has been shown to persist in many mammalian species in two regions of the adult brain: the subgranular zone of the hippocampal dentate gyrus and the subependymal zone [SEZ, also subventricular zone] adjacent to the lateral ventricles [1, 2]. Lower levels of neurogenesis have been reported in other regions of the rodent and primate brain, including the neocortex [3, 4], amygdala [5] and substantia nigra [6], but this has been difficult to replicate consistently other than in the diseased brain [7]. Other studies provided compelling evidence that precursor …show more content…
Adult neurogenesis in the subependymal zone
In the human brain, the adult SEZ is a four-layered structure, with a monolayer of ependymal cells (layer I), a hypocellular gap (layer II), an astrocytic ribbon of cells composed of astrocytes (layer III), and a transitory zone (layer IV) [11, 12]. Neural stem cells with astrocyte-like properties (type B cells) reside in the astrocytic ribbon and typically express glutamate-aspartate transporter, nestin and the δ-isoform of glial fibrillary acidic protein (Figure 1) [13-15]. These type B cells need to re-enter the cell cycle in order to generate transit amplifying progenitor cells (type C cells), which in turn produce neuroblasts …show more content…
Ependymal cells that face the lateral ventricles, are coverd by cilia and microvilli, and represent critical regulators of stem cell self-renewal and neuronal determination by releasing neurogenic factors, such as noggin, which inhibits gliogenesis and promotes neurogenesis [27], and the pigment epithelium-derived factor, which participates in the maintenance of neural precursor cells [28]. Neurogenic niches are closely located to the vasculature [29, 30], where endothelial cells provide an important promotor of adult neurogenesis, the vascular endothelial growth factors [31, 32]. Microglia have been detected in both neurogenic regions in the adult brain, and experimental evidence indicates that they can be either detrimental or supportive for adult neurogenesis depending on their state of activation and functional phenotype