scholarly journals Activation of a neural stem cell transcriptional program in parenchymal astrocytes

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jens P Magnusson ◽  
Margherita Zamboni ◽  
Giuseppe Santopolo ◽  
Jeff E Mold ◽  
Mauricio Barrientos-Somarribas ◽  
...  

Adult neural stem cells, located in discrete brain regions, generate new neurons throughout life. These stem cells are specialized astrocytes, but astrocytes in other brain regions do not generate neurons under physiological conditions. After stroke, however, striatal astrocytes undergo neurogenesis in mice, triggered by decreased Notch signaling. We used single-cell RNA sequencing to characterize neurogenesis by Notch-depleted striatal astrocytes in vivo. Striatal astrocytes were located upstream of neural stem cells in the neuronal lineage. As astrocytes initiated neurogenesis, they became transcriptionally very similar to subventricular zone stem cells, progressing through a near-identical neurogenic program. Surprisingly, in the non-neurogenic cortex, Notch-depleted astrocytes also initiated neurogenesis. Yet, these cortical astrocytes, and many striatal ones, stalled before entering transit-amplifying divisions. Infusion of epidermal growth factor enabled stalled striatal astrocytes to resume neurogenesis. We conclude that parenchymal astrocytes are latent neural stem cells and that targeted interventions can guide them through their neuronal differentiation.

2020 ◽  
Author(s):  
Jens P. Magnusson ◽  
Margherita Zamboni ◽  
Giuseppe Santopolo ◽  
Jeff E. Mold ◽  
Mauricio Barrientos-Somarribas ◽  
...  

AbstractNeural stem cells, located in discrete niches in the adult brain, generate new neurons throughout life. These stem cells are specialized astrocytes, but astrocytes in other brain regions do not generate neurons under physiological conditions. After stroke, however, striatal astrocytes undergo neurogenesis in mice, triggered by decreased Notch signaling. We used single-cell RNA sequencing to characterize neurogenesis by Notch-depleted striatal astrocytes in vivo. Striatal astrocytes were located upstream of neural stem cells in the neuronal lineage. As astrocytes initiated neurogenesis, they became transcriptionally very similar to subventricular zone stem cells and progressed through a nearly identical neurogenic program. Surprisingly, in the non- neurogenic cortex, Notch-depleted astrocytes also initiated neurogenesis. Yet, the cortical astrocytes, and many striatal ones, stalled before entering transit- amplifying divisions. Infusion of epidermal growth factor enabled stalled striatal astrocytes to resume neurogenesis. We conclude that parenchymal astrocytes are latent neural stem cells and that targeted interventions can guide them through their neuronal differentiation.


2020 ◽  
Author(s):  
Katja Baur ◽  
Yomn Abdullah ◽  
Claudia Mandl ◽  
Gabriele Hölzl-Wenig ◽  
Yan Shi ◽  
...  

ABSTRACTNeural stem cells (NSCs) in the ventricular-subventricular zone (V-SVZ) contribute to olfaction by being the origin of most adult-born olfactory bulb (OB) interneurons. The current consensus maintains that adult NSCs are radial glialike progenitors apically contacting the lateral ventricle and generating intermediate progenitors migrating at the basal V-SVZ. Whether basal NSCs are present in the V-SVZ is unknown. We here used genetic tagging of NSCs in vivo and additional labelling approaches to reveal that basal NSCs lacking apical attachment represent the largest NSC type in the postnatal V-SVZ from birth onwards. Despite dividing faster than their apical counterpart, basal NSCs still undergo long-term self-renewal and quiescence. Unlike apical NSCs, they are largely devoid of primary cilia and Prominin-1, Nestin and glial fibrillary acidic protein (GFAP) immunoreactivity. Six weeks after viral tagging of apical cells, few descendant cells were detected in the basal V-SVZ, including Sox9+ progenitors and GFAP+ astrocytes, and very rare new neurons in the OB, indicating that adult-born OB neurons originate from basal and not apical NSCs. Consistent with this, we found that pregnancy, a physiological modulator of adult OB neurogenesis, selectively increases the number of basal but not apical NSCs. Lastly, we find that apical NSCs display the highest levels of Notch activation in the neural lineage, and that selective apical downregulation of Notch-signaling effector Hes1 decreases Notch activation while increasing proliferation across the V-SVZ. Thus, apical NSCs act essentially as neurogenesis gatekeepers by modulating Notch-mediated lateral inhibition of proliferation in the adult V-SVZ.Graphical AbstractHighlightsBasal NSCs are the most abundant stem cell type in the adult V-SVZ from birth onwards.Apical and basal NSCs display distinct characteristics and cell cycle progression dynamics.Apical NSCs are not the main source of newly generated adult OB interneurons.Apical NSCs regulate intermediate progenitor proliferation by orchestrating Notch-mediated lateral inhibition.


2004 ◽  
Vol 24 (4) ◽  
pp. 441-448 ◽  
Author(s):  
Ruilan Zhang ◽  
Zhenggang Zhang ◽  
Lei Wang ◽  
Ying Wang ◽  
Anton Gousev ◽  
...  

Stroke increases neurogenesis. The authors investigated whether neural stem cells or progenitor cells in the adult subventricular zone (SVZ) of rats contribute to stroke-induced increase in neurogenesis. After induction of stroke in rats, the numbers of cells immunoreactive to doublecortin, a marker for immature neurons, increased in the ipsilateral SVZ and striatum. Infusion of an antimitotic agent (cytosine-β-D-arabiofuranoside, Ara-C) onto the ipsilateral cortex eliminated more than 98% of actively proliferating cells in the SVZ and doublecortin-positive cells in the ipsilateral striatum. However, doublecortin-positive cells rapidly replenished after antimitotic agent depletion of actively proliferating cells. Depleting the numbers of actively proliferating cells in vivo had no effect on the numbers of neurospheres formed in vitro, yet the numbers of neurospheres derived from stroke rats significantly ( P < 0.05) increased. Neurospheres derived from stroke rats self-renewed and differentiated into neurons and glia. In addition, doublecortin-positive cells generated in the SVZ migrated in a chainlike structure toward ischemic striatum. These findings indicate that in the adult stroke brain, increases in recruitment of neural stem cells contribute to stroke-induced neurogenesis, and that newly generated neurons migrate from the SVZ to the ischemic striatum.


Neuroreport ◽  
2011 ◽  
Vol 22 (9) ◽  
pp. 448-452 ◽  
Author(s):  
Haitao Jia ◽  
Hong Tao ◽  
Ruopeng Feng ◽  
Meiyu Li ◽  
Jie Bai ◽  
...  

2020 ◽  
Author(s):  
Huanhuan Sha ◽  
Peipei Peng ◽  
Bing Li ◽  
Guohua Wei ◽  
Juan Wang ◽  
...  

Abstract Background: Recent years, the number of neonatal patients receiving surgery under general anesthesia is increasing. Previous studies have indicated that ketamine can disturb the proliferation and differentiation of developing neural stem cells (NSCs). Therefore, the safe use of ketamine in pediatric anesthesia has drawn great concern among anesthesiologists and children’s parents. Dexmedetomidine (DEX) is widely used in sedation, antianxiety and analgesia. Recent studies have shown that DEX could provide neuroprotection against anesthetic-induced neurotoxicity in the developing brain. The aim of this in vivo study was to investigate whether DEX had neuroprotective effects on the proliferation and differentiation of NSCs in the subventricular zone (SVZ) following neonatal ketamine exposure. Methods: Postnatal day 7 (PND-7) male Sprague-Dawley rats were equally divided into the following 5 groups: Control group (n=8), ketamine group (n=8), 1 μg/kg DEX+ketamine group (n=8), 5 μg/kg DEX+ketamine group (n=8) and 10 μg/kg DEX+ketamine group (n=8). The proliferation and differentiation of NSCs in the SVZ were assessed by immunostaining with BrdU incorporation. Results: Neonatal ketamine exposure significantly inhibited NSC proliferation and astrocytic differentiation in the SVZ, and neuronal differentiation was markedly promoted. Furthermore, DEX pretreatment reversed the ketamine-induced disturbances in the proliferation and differentiation of NSCs at moderate (5 μg/kg) or high doses (10 μg/kg). Conclusion: Our findings demonstrate that DEX may have neuroprotective effects on NSCs in the SVZ of neonatal rats in a repeated ketamine anesthesia model.


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