Project description:Quiescent neural stem cells (NSCs) in the adult ventricular-subventricular zone (V-SVZ) undergo activation and divide to generate neurons and glia. Here we show that Platelet-derived Growth Factor Receptor beta (PDGFRβ) is expressed by quiescent and early activated adult V-SVZ NSCs, and maintains their quiescence. We further showed that selective deletion of PDGFRβ in adult V-SVZ NSCs leads to activation of quiescent NSCs. We performed RNA-seq on FACS-sorted V-SVZ quiescent, early activated and late activated NSCs, as well as cortical cells from adult 2-4 month old mice.
Project description:Total RNA was isolated from GFAP::GFP+CD133+EGFR-CD24- (quiescent neural stem cells, qNSCs), GFAP::GFP+CD133+EGFR+CD24- (activated neural stem cells, aNSCs) and GFAP::GFP+CD133- EGFR+CD24- (transit amplifying cells, TACs) cells from the adult mouse ventricular-subventricular zone (V-SVZ) (GFAP::GFP mice, Jackson Mice Stock number 003257).
Project description:Long noncoding RNAs (lncRNAs) have been described in cell lines and various whole tissues, but lncRNA analysis of development in vivo is limited. Here, we comprehensively analyze lncRNA expression for the adult mouse subventricular zone neural stem cell lineage. We utilize complementary genome-wide techniques including RNA-seq, RNA CaptureSeq, and ChIP-seq to associate specific lncRNAs with neural cell types, developmental processes, and human disease states. By integrating data from chromatin state maps, custom microarrays, and FACS purification of the subventricular zone lineage, we stringently identify lncRNAs with potential roles in adult neurogenesis. shRNA-mediated knockdown of two such lncRNAs, Six3os and Dlx1as, indicate roles for lncRNAs in the glial-neuronal lineage specification of multipotent adult stem cells. Our data and workflow thus provide a uniquely coherent in vivo lncRNA analysis and form the foundation of a user-friendly online resource for the study of lncRNAs in development and disease. SVZ monolayer cultures were differentiated in vitro for 1, 2, 4 days, and gene expression changes were measured. SVZ lineage was isolated by FACS using established protocols to separate transit amplifying (TA), neuroblast (NB), activated stem cells (NSCs), and niche astrocytes (astros), and gene expression of each cell type was measured. All arrays are Nimblegen Mouse Gene Expression 12x135K Array.
Project description:Long noncoding RNAs (lncRNAs) have been described in cell lines and various whole tissues, but lncRNA analysis of development in vivo is limited. Here, we comprehensively analyze lncRNA expression for the adult mouse subventricular zone neural stem cell lineage. We utilize complementary genome-wide techniques including RNA-seq, RNA CaptureSeq, and ChIP-seq to associate specific lncRNAs with neural cell types, developmental processes, and human disease states. By integrating data from chromatin state maps, custom microarrays, and FACS purification of the subventricular zone lineage, we stringently identify lncRNAs with potential roles in adult neurogenesis. shRNA-mediated knockdown of two such lncRNAs, Six3os and Dlx1as, indicate roles for lncRNAs in the glial-neuronal lineage specification of multipotent adult stem cells. Our data and workflow thus provide a uniquely coherent in vivo lncRNA analysis and form the foundation of a user-friendly online resource for the study of lncRNAs in development and disease. SVZ monolayer cultures were differentiated in vitro for 1,2,4 days, and gene expression changes were measured. SVZ lineage was isolated by FACS using established protocols to separate transit amplifying (TA), neuroblast (NB), activated stem cells (NSCs), and niche astrocytes (astros), and gene expression of each cell type was measured. All arrays are custom lncRNA arrays.
Project description:Following the decline of neurogenesis at birth, progenitors of the subventricular zone (SVZ) remain mostly in a quiescent state in the adult human brain. The mechanisms that regulate this quiescent state are still unclear. Here, we isolated CD271+ progenitors from the aged human SVZ for single-cell RNA sequencing analysis. Our transcriptome data revealed the identity of progenitors of the aged human SVZ as late oligodendrocyte progenitor cells. We identified the Wnt pathway antagonist SFRP1 as a possible signal that promotes quiescence of progenitors from the aged human SVZ. Administration of WAY-316606, a small molecule that inhibits SFRP1 function, stimulates activation of neural stem cells both in vitro and in vivo under homeostatic conditions. Our data unravel a possible mechanism through which progenitors of the adult human SVZ are maintained in a quiescent state and a potential target for stimulating progenitors to re-activate.
Project description:Adult neural stem cells (NSCs) must tightly regulate quiescence and proliferation. Single cell analysis has suggested a continuum of cell states as NSCs exit quiescence. Here we capture and characterize in vitro primed quiescent NSCs and identify LRIG1 as an important regulator. We show that BMP-4 signaling induces a dormant non-cycling quiescent state (d-qNSCs), whereas combined BMP-4/FGF-2 signalling induces a distinct primed quiescent state poised for cell cycle re-entry. Primed quiescent NSCs (p-qNSCs) are defined by high levels of LRIG1 and CD9, as well as an interferon response signature, and can efficiently engraft into the adult subventricular zone (SVZ) niche. Genetic disruption of Lrig1 in vivo within the SVZ NSCs leads an enhanced proliferation. Mechanistically, LRIG1 primes quiescent NSCs for cell cycle re-entry and EGFR responsiveness by enabling EGFR protein levels to increase but limiting signaling activation. LRIG1 is therefore an important functional regulator of NSC exit from quiescence.
Project description:In selected tissutal niches of the adult mouse brain, such as the subventricular zone (SVZ) underlying the lateral ventricles, neurogenesis persists thanks to a population of quiescent neural stem cells, which can be activated (aNSCs) by extrinsic stimuli to initiate proliferation and generate a neurogenic lineage consisting of transit amplifying progenitors (TAPs), neuroblasts (NBs) and newborn neurons. This process is markedly reduced during aging, which might contribute to the cognitive decline of elderly subjects. Recent studies suggest that the aged niche environment may decrease the pool of proliferating neural/stem progenitor cells (NSPCs), and hence adult neurogenesis, by causing transcriptomic changes that favour NSC quiescence over activation. The transcription factors that mediate these changes, however, remain largely unclear. We previously found that the homeobox gene Dbx2 is upregulated in NSPCs of the aged mouse SVZ and can inhibit the growth of young adult NSPC cultures. Here, we show that Dbx2 expression is downregulated by Epidermal Growth Factor Receptor signalling, which promotes NSPC proliferation and decreases in the aged SVZ. By means of transgenic NSPC lines, we also show that Dbx2 inhibits NSPC proliferation by hindering the G1/S and the G2/M transition. Furthermore, we exploit RNA sequencing of transgenic NSPCs to elucidate the transcriptional networks modulated by Dbx2. Among the top hits, we report the downregulation of several gene categories implicated in cell cycle progression. Accordingly, we find that Dbx2 function is negatively correlated with the transcriptional signatures of proliferative NSPCs (aNSCs, TAPs and early NBs). Altogether, these results point to Dbx2 as a potential molecular node relaying the extracellular anti-neurogenic input of the aged niche to the NSPC transcriptome.
Project description:After a stroke, the neurogenic response from the subventricular zone (SVZ) to repair the brain is limited. Microglia, as an integral part of the distinctive SVZ microenvironment, control neural stem / precursor cell (NSPC) behavior. Here, we show that discrete stroke-associated SVZ microglial clusters negatively impact the innate neurogenic response, and we propose a repository of relevant microglia–NSPC ligand–receptor pairs. After photothrombosis, a mouse model of ischemic stroke, the altered SVZ niche environment leads to immediate activation of microglia in the niche and an abnormal neurogenic response, with cell-cycle arrest of neural stem cells and neuroblast cell death. Pharmacological restoration of the niche environment increases the SVZ-derived neurogenic repair and microglial depletion increases the formation and survival of newborn neuroblasts in the SVZ. Therefore, we propose that altered cross-communication between microglial subclusters and NSPCs regulates the extent of the innate neurogenic repair response in the SVZ after stroke.
Project description:Transcriptional profiling of the microdissected SVZ from 7-month-old mice Adult neurogenesis is suppressed in the SVZ of 3xTg mice, a model of Alzheimer's disease. To better understand the underlying mechanisms of this suppression, the goals of this experiment were to compare the transcriptional profiles of the SVZ neural stem cell niche in 3xTg-AD mice versus strain controls. We used early middle-aged mice (7-months-old) rather than old mice, in order to identify genetic changes that are not caused secondarily to other degenerative changes occurring in these mice. Two-condition experiment, 3xTg vs WT SVZ. Biological replicates: 4 for each.