Publications by authors named "Olivier Raineteau"

47 Publications

Neural processing of the reward value of pleasant odorants.

Curr Biol 2021 Feb 18. Epub 2021 Feb 18.

CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France. Electronic address:

Pleasant odorants are represented in the posterior olfactory bulb (pOB) in mice. How does this hedonic information generate odor-motivated behaviors? Using optogenetics, we report here that stimulating the representation of pleasant odorants in a sensory structure, the pOB, can be rewarding, self-motivating, and is accompanied by ventral tegmental area activation. To explore the underlying neural circuitry downstream of the olfactory bulb (OB), we use 3D high-resolution imaging and optogenetics and determine that the pOB preferentially projects to the olfactory tubercle, whose increased activity is related to odorant attraction. We further show that attractive odorants act as reinforcers in dopamine-dependent place preference learning. Finally, we extend those findings to humans, who exhibit place preference learning and an increase BOLD signal in the olfactory tubercle in response to attractive odorants. Thus, strong and persistent attraction induced by some odorants is due to a direct gateway from the pOB to the reward system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2021.01.066DOI Listing
February 2021

Apoptosis, G1 Phase Stall, and Premature Differentiation Account for Low Chimeric Competence of Human and Rhesus Monkey Naive Pluripotent Stem Cells.

Stem Cell Reports 2021 Jan 30;16(1):56-74. Epub 2020 Dec 30.

Univ Lyon, Université Lyon 1, INSERM, Stem Cell and Brain Research Institute U1208, 69500 Bron, France. Electronic address:

After reprogramming to naive pluripotency, human pluripotent stem cells (PSCs) still exhibit very low ability to make interspecies chimeras. Whether this is because they are inherently devoid of the attributes of chimeric competency or because naive PSCs cannot colonize embryos from distant species remains to be elucidated. Here, we have used different types of mouse, human, and rhesus monkey naive PSCs and analyzed their ability to colonize rabbit and cynomolgus monkey embryos. Mouse embryonic stem cells (ESCs) remained mitotically active and efficiently colonized host embryos. In contrast, primate naive PSCs colonized host embryos with much lower efficiency. Unlike mouse ESCs, they slowed DNA replication after dissociation and, after injection into host embryos, they stalled in the G1 phase and differentiated prematurely, regardless of host species. We conclude that human and non-human primate naive PSCs do not efficiently make chimeras because they are inherently unfit to remain mitotically active during colonization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.stemcr.2020.12.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815945PMC
January 2021

Accelerated Dystrophy and Decay of Oligodendrocyte Precursor Cells in the APP/PS1 Model of Alzheimer's-Like Pathology.

Front Cell Neurosci 2020 3;14:575082. Epub 2020 Dec 3.

School of Pharmacy and Biomedical Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, United Kingdom.

Myelin disruption is a feature of natural aging and Alzheimer's disease (AD). In the CNS, myelin is produced by oligodendrocytes, which are generated throughout life by oligodendrocyte progenitor cells (OPCs). Here, we examined age-related changes in OPCs in APP/PS1 mice, a model for AD-like pathology, compared with non-transgenic (Tg) age-matched controls. The analysis was performed in the CA1 area of the hippocampus following immunolabeling for NG2 with the nuclear dye Hoescht, to identify OPC and OPC sister cells, a measure of OPC replication. The results indicate a significant decrease in the number of OPCs at 9 months in APP/PS1 mice, compared to age-matched controls, without further decline at 14 months. Also, the number of OPC sister cells declined significantly at 14 months in APP/PS1 mice, which was not observed in age-matched controls. Notably, OPCs also displayed marked morphological changes at 14 months in APP/PS1 mice, characterized by an overall shrinkage of OPC process domains and increased process branching. The results indicate that OPC disruption is a pathological sign in the APP/PS1 mouse model of AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fncel.2020.575082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7744306PMC
December 2020

Experimental glioma with high bHLH expression harbor increased replicative stress and are sensitive toward ATR inhibition.

Neurooncol Adv 2020 Jan-Dec;2(1):vdaa115. Epub 2020 Sep 10.

Department of Neurology and Interdisciplinary Neuro-Oncology, Hertie Institute for Clinical Brain Research, University Hospital Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany.

Background: The overexpression of (basic)helix-loop-helix ((b)HLH) transcription factors (TFs) is frequent in malignant glioma. We investigated molecular effects upon disruption of the (b)HLH network by a dominant-negative variant of the E47 protein (dnE47). Our goal was to identify novel molecular subgroup-specific therapeutic strategies.

Methods: Glioma cell lines LN229, LNZ308, and GS-2/GS-9 were lentivirally transduced. Functional characterization included immunocytochemistry, immunoblots, cytotoxic, and clonogenic survival assays in vitro, and latency until neurological symptoms in vivo. Results of cap analysis gene expression and RNA-sequencing were further validated by immunoblot, flow cytometry, and functional assays in vitro.

Results: The induction of dnE47-RFP led to cytoplasmic sequestration of (b)HLH TFs and antiglioma activity in vitro and in vivo. Downstream molecular events, ie, alterations in transcription start site usage and in the transcriptome revealed enrichment of cancer-relevant pathways, particularly of the DNA damage response (DDR) pathway. Pharmacologic validation of this result using ataxia telangiectasia and Rad3 related (ATR) inhibition led to a significantly enhanced early and late apoptotic effect compared with temozolomide alone.

Conclusions: Gliomas overexpressing (b)HLH TFs are sensitive toward inhibition of the ATR kinase. The combination of ATR inhibition plus temozolomide or radiation therapy in this molecular subgroup are warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/noajnl/vdaa115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7592426PMC
September 2020

Contributions of Single-Cell Approaches for Probing Heterogeneity and Dynamics of Neural Progenitors Throughout Life: Concise Review.

Stem Cells 2019 11 20;37(11):1381-1388. Epub 2019 Aug 20.

Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France.

Development of the forebrain occurs in a stepwise manner from a pool of neural progenitors (NPs), which differs over space and time to produce distinct progenies. The sequence of events leading to the generation of the exquisite complexity of cell types that compose this tissue has been described in great detail at the population level. Recent advances in histology and transcriptomics have allowed probing spatial and temporal heterogeneity and dynamics of NPs at the single-cell level. Clonal fate mapping studies highlight a deterministic behavior as well as the existence of trajectories in the lineage progression of prenatal and postnatal NPs, whereas single-cell transcriptomic studies shed new light on the transcriptional signatures of these processes. Here, we review this recent work and integrate it to our current understanding of forebrain germinal activity at prenatal and postnatal time points. Stem Cells 2019;37:1381-1388.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/stem.3071DOI Listing
November 2019

"FlashMap" - A Semi-Automatic Tool for Rapid and Accurate Spatial Analysis of Marker Expression in the Subventricular Zone.

Sci Rep 2018 10 31;8(1):16086. Epub 2018 Oct 31.

Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500, Bron, France.

The subventricular zone (SVZ) is a region of ongoing postnatal germinal activity that shows complex spatial heterogeneity. For instance, different SVZ microdomains contain neural stem cells that express distinct transcription factors and generate different glial and neuronal progenies. These unique characteristics call for the development of new methods to integrate a spatial dimension to histological analyses performed in this germinal region. We developed "FlashMap", a semi-automatic software that allows the segmentation and rapid measurement of optical densities throughout the full SVZ coordinates. "FlashMap" generates easily readable two-dimensional heatmaps that can be superimposed onto three-dimensional reconstructions of the ventricular system for optimal spatial exploration. Accurate heatmaps can be obtained, even following serial section subsampling thereby reducing the amount of tissue and time required for histological analysis. We first illustrate the potential of "FlashMap" by spatially exploring the correlation of SVZ thickness and cellular density with germinal activity throughout its rostro-caudal coordinates. We then used "FlashMap" to analyse the spatial expression of the transcription factors Dlx2, Tbr2 and Hopx as well as of the immature neuronal marker Dcx, to demonstrate the suitability of this approach to explore the regional production of cells of distinct lineages by defined SVZ microdomains.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-33939-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6208407PMC
October 2018

A Pool of Postnatally Generated Interneurons Persists in an Immature Stage in the Olfactory Bulb.

J Neurosci 2018 11 3;38(46):9870-9882. Epub 2018 Oct 3.

Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France, and

Calretinin (CR)-expressing periglomerular (PG) cells are the most abundant interneurons in the glomerular layer of the olfactory bulb. They are predominately generated postnatally from the septal and dorsal subventricular zones that continue producing them well into adulthood. Yet, little is known about their properties and functions. Using transgenic approaches and patch-clamp recording in mice of both sexes we show that CR(+) PG cells of both septal and dorsal origin have homogeneous morphological and electrophysiological properties. However, unlike other PG cells, these axonless neurons express a surprisingly small repertoire of voltage-activated channels and do not fire or fire at most a single and often small action potential. Moreover, they are not innervated by olfactory sensory neurons and receive little synaptic inputs from mitral or tufted cells at excitatory synapses where NMDA receptors predominate. These membrane and synaptic properties, that resemble those of newborn immature neurons not yet integrated in the network, persist over time and limit the recruitment of CR(+) PG cells by afferent inputs that strongly drive local network activity. Together, our results show that postnatally generated CR(+) PG cells continuously supply a large pool of neurons with unconventional properties. These data also question the contribution of CR(+) PG cells in olfactory bulb computation. Calretinin-expressing PG cells are by far the most abundant interneurons in the glomerular layer of the olfactory bulb. They are continuously produced during postnatal life, including adulthood, from neural stem cells located in the subventricular zones. Surprisingly, unlike other postnatally generated newborn neurons that quickly integrate into preexisting olfactory bulb networks, calretinin-expressing PG cells retain immature properties that limit their recruitment in local network activity for weeks, if not months, as if they would never fully mature. The function of this so far unsuspected pool of latent neurons is still unknown.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.1216-18.2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6596244PMC
November 2018

A dual role for the transcription factor Sp8 in postnatal neurogenesis.

Sci Rep 2018 09 28;8(1):14560. Epub 2018 Sep 28.

Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France.

Neural stem cells (NSCs) of the postnatal subventricular zone (SVZ) continue producing distinct subtypes of olfactory bulb (OB) interneurons throughout life. Understanding the transcriptional coding of this diversity remains a great challenge of modern neurosciences. Interneurons expressing calretinin (CalR) represent the main interneuron subtype produced in the glomerular cell layer (GL) after birth. Previous studies have suggested that their specification relies on expression of the transcription factor Sp8 by SVZ NSCs. In this study, we performed fate mapping of NSCs that generate CalR+ or non-CalR+ interneurons, in order to assess the pattern of Sp8 expression during postnatal neurogenesis. We highlight a complex pattern of Sp8 expression, which appears to be expressed in all interneurons lineages, before getting gradually restricted to maturing CalR+ interneurons. To decipher the early and late functions of Sp8 in postnatal OB neurogenesis, we combined transient, permanent and conditional genetic approaches to manipulate Sp8 at distinct neurogenic stages. While Sp8 plays an early role in controlling proliferation in all lineages, it is not involved in the early specification of CalR+ periglomerular interneurons, but plays a crucial role in their long term survival. Together, our results highlight a crucial and dual role for Sp8 during postnatal neurogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-32134-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162233PMC
September 2018

HOPX Defines Heterogeneity of Postnatal Subventricular Zone Neural Stem Cells.

Stem Cell Reports 2018 09 30;11(3):770-783. Epub 2018 Aug 30.

Université de Lyon, Université Claude Bernard Lyon 1, INSERM, Stem Cell and Brain Research Institute U1208, Bron 69500, France. Electronic address:

The largest diversity of neural lineages generated from the subventricular zone (SVZ) occurs early after birth and is regulated in a spatiotemporal manner depending on the expression of specific transcriptional cues. Transcriptomics and fate-mapping approaches were employed to explore the relationship between regional expression of transcription factors by neural stem cells (NSCs) and the specification of distinct neural lineages. Our results support an early priming of NSCs for the genesis of defined cell types depending on their spatial location in the SVZ and identify HOPX as a marker of a subpopulation primed toward astrocytic fates. Manipulation of HOPX expression, however, showed no effect on astrogenesis but resulted in marked changes in the number of NSCs and of their progenies. Taken together, our results highlight transcriptional and spatial heterogeneity of postnatal NSCs and reveal a key role for HOPX in controlling SVZ germinal activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.stemcr.2018.08.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6135899PMC
September 2018

Transcriptional Dysregulation in Postnatal Glutamatergic Progenitors Contributes to Closure of the Cortical Neurogenic Period.

Cell Rep 2018 03;22(10):2567-2574

Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France; Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland. Electronic address:

Progenitors of cortical glutamatergic neurons (Glu progenitors) are usually thought to switch fate before birth to produce astrocytes. We used fate-mapping approaches to show that a large fraction of Glu progenitors persist in the postnatal forebrain after closure of the cortical neurogenesis period. Postnatal Glu progenitors do not accumulate during embryonal development but are produced by embryonal radial glial cells that persist after birth in the dorsal subventricular zone and continue to give rise to cortical neurons, although with low efficiency. Single-cell RNA sequencing reveals a dysregulation of transcriptional programs, which parallels changes in mA methylation and correlates with the gradual decline in cortical neurogenesis observed in vivo. Rescuing experiments show that postnatal progenitors are partially permissive to genetic and pharmacological manipulations. Our study provides an in-depth characterization of postnatal Glu progenitors and identifies potential therapeutic targets for promoting brain repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2018.02.030DOI Listing
March 2018

Pharmacogenomic identification of small molecules for lineage specific manipulation of subventricular zone germinal activity.

PLoS Biol 2017 03 28;15(3):e2000698. Epub 2017 Mar 28.

Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland.

Strategies for promoting neural regeneration are hindered by the difficulty of manipulating desired neural fates in the brain without complex genetic methods. The subventricular zone (SVZ) is the largest germinal zone of the forebrain and is responsible for the lifelong generation of interneuron subtypes and oligodendrocytes. Here, we have performed a bioinformatics analysis of the transcriptome of dorsal and lateral SVZ in early postnatal mice, including neural stem cells (NSCs) and their immediate progenies, which generate distinct neural lineages. We identified multiple signaling pathways that trigger distinct downstream transcriptional networks to regulate the diversity of neural cells originating from the SVZ. Next, we used a novel in silico genomic analysis, searchable platform-independent expression database/connectivity map (SPIED/CMAP), to generate a catalogue of small molecules that can be used to manipulate SVZ microdomain-specific lineages. Finally, we demonstrate that compounds identified in this analysis promote the generation of specific cell lineages from NSCs in vivo, during postnatal life and adulthood, as well as in regenerative contexts. This study unravels new strategies for using small bioactive molecules to direct germinal activity in the SVZ, which has therapeutic potential in neurodegenerative diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pbio.2000698DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5370089PMC
March 2017

Postnatal Neural Stem Cells: Probing Their Competence for Cortical Repair.

Neuroscientist 2017 12 16;23(6):605-615. Epub 2017 Mar 16.

1 Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute, Bron, France.

There is growing evidence for a tentative cellular repair in the forebrain following perinatal injuries. In this review, we present the evidences and shortcomings in this regenerative attempt. We discuss recent progress in elucidating the origin, diversity, and competence of postnatal neural stem cells/progenitor cells. Finally, we propose new strategies to recruit postnatal progenitors to generate specific subtypes of cortical neurons or oligodendrocytes, thereby allowing the development of tailor-made approaches to treat perinatal brain injuries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1073858417697036DOI Listing
December 2017

Mosaic Subventricular Origins of Forebrain Oligodendrogenesis.

Front Neurosci 2016 24;10:107. Epub 2016 Mar 24.

Inserm U1208, Stem Cell and Brain Research Institute, Université Lyon 1 Bron, France.

In the perinatal as well as the adult CNS, the subventricular zone (SVZ) of the forebrain is the largest and most active source of neural stem cells (NSCs) that generates neurons and oligodendrocytes (OLs), the myelin forming cells of the CNS. Recent advances in the field are beginning to shed light regarding SVZ heterogeneity, with the existence of spatially segregated microdomains that are intrinsically biased to generate phenotypically distinct neuronal populations. Although most research has focused on this regionalization in the context of neurogenesis, newer findings underline that this also applies for the genesis of OLs under the control of specific patterning molecules. In this mini review, we discuss the origins as well as the mechanisms that induce and maintain SVZ regionalization. These come in the flavor of specific signaling ligands and subsequent initiation of transcriptional networks that provide a basis for subdividing the SVZ into distinct lineage-specific microdomains. We further emphasize canonical Wnts and FGF2 as essential signaling pathways for the regional genesis of OL progenitors from NSCs of the dorsal SVZ. This aspect of NSC biology, which has so far received little attention, may unveil new avenues for appropriately recruiting NSCs in demyelinating diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnins.2016.00107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4805584PMC
April 2016

[Postnatal subventricular zone regionalization by morphogens].

Med Sci (Paris) 2015 Nov 17;31(11):968-70. Epub 2015 Nov 17.

Inserm U846, Stem cell and brain research Institute (SBRI), 18, avenue Doyen Lépine, 69500 Bron, France université de Lyon, université Lyon 1, 69500, Bron, France.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1051/medsci/20153111010DOI Listing
November 2015

Septo-temporal distribution and lineage progression of hippocampal neurogenesis in a primate (Callithrix jacchus) in comparison to mice.

Front Neuroanat 2015 29;9:85. Epub 2015 Jun 29.

Neuroscience Center Zurich, University of Zürich and ETH Zürich Zürich, Switzerland.

Adult born neurons in the hippocampus show species-specific differences in their numbers, the pace of their maturation and their spatial distribution. Here, we present quantitative data on adult hippocampal neurogenesis in a New World primate, the common marmoset (Callithrix jacchus) that demonstrate parts of the lineage progression and age-related changes. Proliferation was largely (∼70%) restricted to stem cells or early progenitor cells, whilst the remainder of the cycling pool could be assigned almost exclusively to Tbr2+ intermediate precursor cells in both neonate and adult animals (20-122 months). Proliferating DCX+ neuroblasts were virtually absent in adults, although rare MCM2+/DCX+ co-expression revealed a small, persisting proliferative potential. Co-expression of DCX with calretinin was very limited in marmosets, suggesting that these markers label distinct maturational stages. In adult marmosets, numbers of MCM2+, Ki67+, and significantly Tbr2+, DCX+, and CR+ cells declined with age. The distributions of granule cells, proliferating cells and DCX+ young neurons along the hippocampal longitudinal axis were equal in marmosets and mice. In both species, a gradient along the hippocampal septo-temporal axis was apparent for DCX+ and resident granule cells. Both cell numbers are higher septally than temporally, whilst proliferating cells were evenly distributed along this axis. Relative to resident granule cells, however, the ratio of proliferating cells and DCX+ neurons remained constant in the septal, middle, and temporal hippocampus. In marmosets, the extended phase of the maturation of young neurons that characterizes primate hippocampal neurogenesis was due to the extension in a large CR+/DCX- cell population. This clear dissociation between DCX+ and CR+ young neurons has not been reported for other species and may therefore represent a key primate-specific feature of adult hippocampal neurogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnana.2015.00085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4484228PMC
July 2015

Adding a spatial dimension to postnatal ventricular-subventricular zone neurogenesis.

Development 2015 Jun;142(12):2109-20

Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland Inserm U846, Stem Cell and Brain Research Institute, 18 Avenue Doyen Lépine, Bron 69500, France Université de Lyon, Université Lyon 1, Bron 69500, France

Neurogenesis does not stop abruptly at birth, but persists in specific brain regions throughout life. The neural stem cells (NSCs) located in the largest germinal region of the forebrain, the ventricular-subventricular zone (V-SVZ), replenish olfactory neurons throughout life. However, V-SVZ NSCs are heterogeneous: they have different embryonic origins and give rise to distinct neuronal subtypes depending on their location. In this Review, we discuss how this spatial heterogeneity arises, how it affects NSC biology, and why its consideration in future studies is crucial for understanding general principles guiding NSC self-renewal, differentiation and specification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1242/dev.119966DOI Listing
June 2015

Transcriptional Hallmarks of Heterogeneous Neural Stem Cell Niches of the Subventricular Zone.

Stem Cells 2015 Jul 23;33(7):2232-42. Epub 2015 Apr 23.

Brain Research Institute, University of Zurich/ETH Zurich, Zurich, Switzerland.

Throughout postnatal life in mammals, neural stem cells (NSCs) are located in the subventricular zone (SVZ) of the lateral ventricles. The greatest diversity of neuronal and glial lineages they generate occurs during early postnatal life in a region-specific manner. In order to probe heterogeneity of the postnatal SVZ, we microdissected its dorsal and lateral walls at different postnatal ages and isolated NSCs and their immediate progeny based on their expression of Hes5-EGFP/Prominin1 and Ascl1-EGFP, respectively. Whole genome comparative transcriptome analysis revealed transcriptional regulators as major hallmarks that sustain postnatal SVZ regionalization. Manipulation of single genes encoding for locally enriched transcription factors (loss-of-function or ectopic gain-of-function in vivo) influenced NSC specification indicating that the fate of regionalized postnatal SVZ-NSCs can be readily modified. These findings reveal the pronounced transcriptional heterogeneity of the postnatal SVZ and provide targets to recruit region-specific lineages in regenerative contexts. Stem Cells 2015;33:2232-2242.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/stem.2017DOI Listing
July 2015

E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain.

Neural Dev 2014 Oct 29;9:23. Epub 2014 Oct 29.

Brain Research Institute, ETH Zurich/University of Zurich, 8057 Zurich, Switzerland.

Background: Neural stem cell (NSC) differentiation is a complex multistep process that persists in specific regions of the postnatal forebrain and requires tight regulation throughout life. The transcriptional control of NSC proliferation and specification involves Class II (proneural) and Class V (Id1-4) basic helix-loop-helix (bHLH) proteins. In this study, we analyzed the pattern of expression of their dimerization partners, Class I bHLH proteins (E-proteins), and explored their putative role in orchestrating postnatal subventricular zone (SVZ) neurogenesis.

Results: Overexpression of a dominant-negative form of the E-protein E47 (dnE47) confirmed a crucial role for bHLH transcriptional networks in postnatal neurogenesis by dramatically blocking SVZ NSC differentiation. In situ hybridization was used in combination with RT-qPCR to measure and compare the level of expression of E-protein transcripts (E2-2, E2A, and HEB) in the neonatal and adult SVZ as well as in magnetic affinity cell sorted progenitor cells and neuroblasts. Our results evidence that E-protein transcripts, in particular E2-2 and E2A, are enriched in the postnatal SVZ with expression levels increasing as cells engage towards neuronal differentiation. To investigate the role of E-proteins in orchestrating lineage progression, both in vitro and in vivo gain-of-function and loss-of-function experiments were performed for individual E-proteins. Overexpression of E2-2 and E2A promoted SVZ neurogenesis by enhancing not only radial glial cell differentiation but also cell cycle exit of their progeny. Conversely, knock-down by shRNA electroporation resulted in opposite effects. Manipulation of E-proteins and/or Ascl1 in SVZ NSC cultures indicated that those effects were Ascl1 dependent, although they could not solely be attributed to an Ascl1-induced switch from promoting cell proliferation to triggering cell cycle arrest and differentiation.

Conclusions: In contrast to former concepts, suggesting ubiquitous expression and subsidiary function for E-proteins to foster postnatal neurogenesis, this work unveils E-proteins as being active players in the orchestration of postnatal SVZ neurogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1749-8104-9-23DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4274746PMC
October 2014

Calsyntenin-1 regulates targeting of dendritic NMDA receptors and dendritic spine maturation in CA1 hippocampal pyramidal cells during postnatal development.

J Neurosci 2014 Jun;34(26):8716-27

Brain Research Institute and

Calsyntenin-1 is a transmembrane cargo-docking protein important for kinesin-1-mediated fast transport of membrane-bound organelles that exhibits peak expression levels at postnatal day 7. However, its neuronal function during postnatal development remains unknown. We generated a knock-out mouse to characterize calsyntenin-1 function in juvenile mice. In the absence of calsyntenin-1, synaptic transmission was depressed. To address the mechanism, evoked EPSPs were analyzed revealing a greater proportion of synaptic GluN2B subunit-containing receptors typical for less mature synapses. This imbalance was due to a disruption in calsyntenin-1-mediated dendritic transport of NMDA receptor subunits. As a consequence of increased expression of GluN2B subunits, NMDA receptor-dependent LTP was enhanced at Schaffer collateral-CA1 pyramidal cell synapses. Interestingly, these defects were accompanied by a decrease in dendritic arborization and increased proportions of immature filopodia-like dendritic protrusions at the expense of thin-type dendritic spines in CA1 pyramidal cells. Thus, these results highlight a key role for calsyntenin-1 in the transport of NMDA receptors to synaptic targets, which is necessary for the maturation of neuronal circuits during early development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.0144-14.2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6608200PMC
June 2014

Targeting the bHLH transcriptional networks by mutated E proteins in experimental glioma.

Stem Cells 2014 Oct;32(10):2583-95

Brain Research Institute, University of Zurich/Swiss Federal Institute of Technology Zurich, Zurich, Switzerland.

Glioblastomas (GB) are aggressive primary brain tumors. Helix-loop-helix (HLH, ID proteins) and basic HLH (bHLH, e.g., Olig2) proteins are transcription factors that regulate stem cell proliferation and differentiation throughout development and into adulthood. Their convergence on many oncogenic signaling pathways combined with the observation that their overexpression in GB correlates with poor clinical outcome identifies these transcription factors as promising therapeutic targets. Important dimerization partners of HLH/bHLH proteins are E proteins that are necessary for nuclear translocation and DNA binding. Here, we overexpressed a wild type or a dominant negative form of E47 (dnE47) that lacks its nuclear localization signal thus preventing nuclear translocation of bHLH proteins in long-term glioma cell lines and in glioma-initiating cell lines and analyzed the effects in vitro and in vivo. While overexpression of E47 was sufficient to induce apoptosis in absence of bHLH proteins, dnE47 was necessary to prevent nuclear translocation of Olig2 and to achieve similar proapoptotic responses. Transcriptional analyses revealed downregulation of the antiapoptotic gene BCL2L1 and the proproliferative gene CDC25A as underlying mechanisms. Overexpression of dnE47 in glioma-initiating cell lines with high HLH and bHLH protein levels reduced sphere formation capacities and expression levels of Nestin, BCL2L1, and CDC25A. Finally, the in vivo induction of dnE47 expression in established xenografts prolonged survival. In conclusion, our data introduce a novel approach to jointly neutralize HLH and bHLH transcriptional networks activities, and identify these transcription factors as potential targets in glioma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/stem.1776DOI Listing
October 2014

GSK3β regulates oligodendrogenesis in the dorsal microdomain of the subventricular zone via Wnt-β-catenin signaling.

Glia 2014 May;62(5):778-9

Oligodendrocytes, the myelinating cells of the CNS, are derived postnatally from oligodendrocyte precursors (OPs) of the subventricular zone (SVZ). However, the mechanisms that regulate their generation from SVZ neural stem cells (NSC) are poorly understood. Here, we have examined the role of glycogen synthase kinase 3β (GSK3β), an effector of multiple converging signaling pathways in postnatal mice. The expression of GSK3β by rt-qPCR was most prominent in the SVZ and in the developing white matter, around the first 1–2 weeks of postnatal life, coinciding with the peak periods of OP differentiation. Intraventricular infusion of the GSK3β inhibitor ARA-014418 in mice aged postnatal day (P) 8–11 significantly increased generation of OPs in the dorsal microdomain of the SVZ, as shown by expression of cell specific markers using rt-qPCR and immunolabelling. Analysis of stage specific markers revealed that the augmentation of OPs occurred via increased specification from earlier SVZ cell types. These effects of GSK3β inhibition on the dorsal SVZ were largely attributable to stimulation of the canonical Wnt/β-catenin signaling pathway over other pathways. The results indicate GSK3β is a key endogenous factor for specifically regulating oligodendrogenesis from the dorsal SVZ microdomain under the control of Wnt-signaling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/glia.22641DOI Listing
May 2014

Persistent Wnt/β-catenin signaling determines dorsalization of the postnatal subventricular zone and neural stem cell specification into oligodendrocytes and glutamatergic neurons.

Stem Cells 2014 May;32(5):1301-12

Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland.

In the postnatal and adult central nervous system (CNS), the subventricular zone (SVZ) of the forebrain is the main source of neural stem cells (NSCs) that generate olfactory neurons and oligodendrocytes (OLs), the myelinating cells of the CNS. Here, we provide evidence of a primary role for canonical Wnt/β-catenin signaling in regulating NSC fate along neuronal and oligodendroglial lineages in the postnatal SVZ. Our findings demonstrate that glutamatergic neuronal precursors (NPs) and oligodendrocyte precursors (OPs) are derived strictly from the dorsal SVZ (dSVZ) microdomain under the control of Wnt/β-catenin, whereas GABAergic NPs are derived mainly from the lateral SVZ (lSVZ) microdomain independent of Wnt/β-catenin. Transcript analysis of microdissected SVZ microdomains revealed that canonical Wnt/β-catenin signaling was more pronounced in the dSVZ microdomain. This was confirmed using the β-catenin-activated Wnt-reporter mouse and by pharmacological stimulation of Wnt/β-catenin by infusion of the specific glycogen synthase kinase 3β inhibitor, AR-A014418, which profoundly increased the generation of cycling cells. In vivo genetic/pharmacological stimulation or inhibition of Wnt/β-catenin, respectively, increased and decreased the differentiation of dSVZ-NSCs into glutamatergic NPs, and had a converse effect on GABAergic NPs. Activation of Wnt/β-catenin dramatically stimulated the generation of OPs, but its inhibition had no effect, indicating other factors act in concert with Wnt/β-catenin to fine tune oligodendrogliogenesis in the postnatal dSVZ. These results demonstrate a role for Wnt/β-catenin signaling within the dorsal microdomain of the postnatal SVZ, in regulating the genesis of glutamatergic neurons and OLs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/stem.1639DOI Listing
May 2014

The adult spinal cord harbors a population of GFAP-positive progenitors with limited self-renewal potential.

Glia 2013 Dec 7;61(12):2100-13. Epub 2013 Oct 7.

Brain Research Institute, University of Zurich/ETHZ, Switzerland.

Adult neural stem cells (aNSCs) of the forebrain are GFAP-expressing cells that are intercalated within ependymal cells of the subventricular zone (SVZ). Cells showing NSCs characteristics in vitro can also be isolated from the periaqueductal region in the adult spinal cord (SC), but contradicting results exist concerning their glial versus ependymal identity. We used an inducible transgenic mouse line (hGFAP-CreERT2) to conditionally label GFAP-expressing cells in the adult SVZ and SC periaqueduct, and directly and systematically compared their self-renewal and multipotential properties in vitro. We demonstrate that a population of GFAP(+) cells that share the morphology and the antigenic properties of SVZ-NSCs mostly reside in the dorsal aspect of the central canal (CC) throughout the spinal cord. These cells are non-proliferative in the intact spinal cord, but incorporate the S-phase marker EdU following spinal cord injury. Multipotent, clonal YFP-expressing neurospheres (i.e., deriving from recombined GFAP-expressing cells) were successfully obtained from both the intact and injured spinal cord. These spheres however showed limited self-renewal properties when compared with SVZ-neurospheres, even after spinal cord injury. Altogether, these results demonstrate that significant differences exist in NSCs lineages between neurogenic and non-neurogenic regions of the adult CNS. Thus, although we confirm that a population of multipotent GFAP(+) cells co-exists alongside with multipotent ependymal cells within the adult SC, we identify these cells as multipotent progenitors showing limited self-renewal properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/glia.22579DOI Listing
December 2013

Molecular diversity subdivides the adult forebrain neural stem cell population.

Stem Cells 2014 Jan;32(1):70-84

Embryology and Stem Cell Biology, Department of Biomedicine, University of Basel, Basel, Switzerland; Department of Molecular Embryology, Max Planck Institute of Immunobiology, Freiburg, Germany.

Neural stem cells (NSCs) in the ventricular domain of the subventricular zone (V-SVZ) of rodents produce neurons throughout life while those in humans become largely inactive or may be lost during infancy. Most adult NSCs are quiescent, express glial markers, and depend on Notch signaling for their self-renewal and the generation of neurons. Using genetic markers and lineage tracing, we identified subpopulations of adult V-SVZ NSCs (type 1, 2, and 3) indicating a striking heterogeneity including activated, brain lipid binding protein (BLBP, FABP7) expressing stem cells. BLBP(+) NSCs are mitotically active components of pinwheel structures in the lateral ventricle walls and persistently generate neurons in adulthood. BLBP(+) NSCs express epidermal growth factor (EGF) receptor, proliferate in response to EGF, and are a major clonogenic population in the SVZ. We also find BLBP expressed by proliferative ventricular and subventricular progenitors in the fetal and postnatal human brain. Loss of BLBP(+) stem/progenitor cells correlates with reduced neurogenesis in aging rodents and postnatal humans. These findings of molecular heterogeneity and proliferative differences subdivide the NSC population and have implications for neurogenesis in the forebrain of mammals during aging.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/stem.1520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4259462PMC
January 2014

Perisynaptic chondroitin sulfate proteoglycans restrict structural plasticity in an integrin-dependent manner.

J Neurosci 2012 Dec;32(50):18009-17, 18017a

Brain Research Institute, University of Zürich/Eidgenössische Technische Hochschule, 8057 Zürich, Switzerland.

During early postnatal development of the CNS, neuronal networks are configured through the formation, elimination, and remodeling of dendritic spines, the sites of most excitatory synaptic connections. The closure of this critical period for plasticity correlates with the maturation of the extracellular matrix (ECM) and results in reduced dendritic spine dynamics. Chondroitin sulfate proteoglycans (CSPGs) are thought to be the active components of the mature ECM that inhibit functional plasticity in the adult CNS. These molecules are diffusely expressed in the extracellular space or aggregated as perineuronal nets around specific classes of neurons. We used organotypic hippocampal slices prepared from 6-d-old Thy1-YFP mice and maintained in culture for 4 weeks to allow ECM maturation. We performed live imaging of CA1 pyramidal cells to assess the effect of chondroitinase ABC (ChABC)-mediated digestion of CSPGs on dendritic spine dynamics. We found that CSPG digestion enhanced the motility of dendritic spines and induced the appearance of spine head protrusions in a glutamate receptor-independent manner. These changes were paralleled by the activation of β1-integrins and phosphorylation of focal adhesion kinase at synaptic sites, and were prevented by preincubation with a β1-integrin blocking antibody. Interestingly, microinjection of ChABC close to dendritic segments was sufficient to induce spine remodeling, demonstrating that CSPGs located around dendritic spines modulate their dynamics independently of perineuronal nets. This restrictive action of perisynaptic CSPGs in mature neural tissue may account for the therapeutic effects of ChABC in promoting functional recovery in impaired neural circuits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.2406-12.2012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6621736PMC
December 2012

3-dimensional examination of the adult mouse subventricular zone reveals lineage-specific microdomains.

PLoS One 2012 15;7(11):e49087. Epub 2012 Nov 15.

Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland.

Recent studies suggest that the subventricular zone (SVZ) of the lateral ventricle is populated by heterogeneous populations of stem and progenitor cells that, depending on their exact location, are biased to acquire specific neuronal fates. This newly described heterogeneity of SVZ stem and progenitor cells underlines the necessity to develop methods for the accurate quantification of SVZ stem and progenitor subpopulations. In this study, we provide 3-dimensional topographical maps of slow cycling "stem" cells and progenitors based on their unique cell cycle properties. These maps revealed that both cell populations are present throughout the lateral ventricle wall as well as in discrete regions of the dorsal wall. Immunodetection of transcription factors expressed in defined progenitor populations further reveals that divergent lineages have clear regional enrichments in the rostro-caudal as well as in the dorso-ventral span of the lateral ventricle. Thus, progenitors expressing Tbr2 and Dlx2 were confined to dorsal and dorso-lateral regions of the lateral ventricle, respectively, while Mash1+ progenitors were more homogeneously distributed. All cell populations were enriched in the rostral-most region of the lateral ventricle. This diversity and uneven distribution greatly impede the accurate quantification of SVZ progenitor populations. This is illustrated by measuring the coefficient of error of estimates obtained by using increasing section sampling interval. Based on our empirical data, we provide such estimates for all progenitor populations investigated in this study. These can be used in future studies as guidelines to judge if the precision obtained with a sampling scheme is sufficient to detect statistically significant differences between experimental groups if a biological effect is present. Altogether, our study underlines the need to consider the SVZ of the lateral ventricle as a complex 3D structure and define methods to accurately assess neural stem cells or progenitor diversity and population sizes in physiological or experimental paradigms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0049087PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3499551PMC
May 2013

p27(Kip1) is a microtubule-associated protein that promotes microtubule polymerization during neuron migration.

Dev Cell 2012 Oct 27;23(4):729-44. Epub 2012 Sep 27.

GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium.

The migration of cortical interneurons is characterized by extensive morphological changes that result from successive cycles of nucleokinesis and neurite branching. Their molecular bases remain elusive, and the present work describes how p27(Kip1) controls cell-cycle-unrelated signaling pathways to regulate these morphological remodelings. Live imaging reveals that interneurons lacking p27(Kip1) show delayed tangential migration resulting from defects in both nucleokinesis and dynamic branching of the leading process. At the molecular level, p27(Kip1) is a microtubule-associated protein that promotes polymerization of microtubules in extending neurites, thereby contributing to tangential migration. Furthermore, we show that p27(Kip1) controls actomyosin contractions that drive both forward translocation of the nucleus and growth cone splitting. Thus, p27(Kip1) cell-autonomously controls nucleokinesis and neurite branching by regulating both actin and microtubule cytoskeletons.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.devcel.2012.08.006DOI Listing
October 2012

Intraventricular injection of FGF-2 promotes generation of oligodendrocyte-lineage cells in the postnatal and adult forebrain.

Glia 2012 Dec 5;60(12):1977-90. Epub 2012 Sep 5.

Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, St Michael's Building, Portsmouth, United Kingdom.

FGF2 is considered a key factor in the generation of oligodendrocytes (OLs) derived from neural stem cells (NSCs) located within the subventricular zone (SVZ). Here, we have examined FGF2 signaling in the forebrain of postnatal and adult mice. Using qPCR of microdissected microdomains of the dorsal SVZ (dSVZ) and lateral SVZ (lSVZ), and prominin1-sorted NSCs purified from these microdomains, we show that transcripts for FGF receptor 1 (FGFR1) and FGFR2 are enriched in the dSVZ, from which OLs are largely derived, whereas FGFR3 are significantly enriched within prominen1-sorted NSC of the lSVZ, which mainly generate olfactory interneurons. We show that direct administration of FGF2 into the lateral ventricle increased the generation of oligodendrocyte progenitors (OPCs) throughout the SVZ, both within the dSVZ and ectopically in the lSVZ and ependymal wall of the SVZ. Furthermore, FGF2 stimulated proliferation of neural progenitors (NPs) and their differentiation into OPCs. The results indicate that FGF2 increased specification of OPCs, inducing NPs to follow an oligodendrocyte developmental pathway. Notably, FGF2 did not block OPC differentiation and increased the number of oligodendrocytes in the periventricular white matter (PVWM) and cortex. However, FGF2 markedly disrupted myelination in the PVWM. A key finding was that FGF2 had equivalent actions on the generation of OPCs and myelin disruption in postnatal and adult mice. This study demonstrates a central role for FGF2 in promoting oligodendrocyte generation in the developing and adult brain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/glia.22413DOI Listing
December 2012

Early decline in progenitor diversity in the marmoset lateral ventricle.

Cereb Cortex 2013 Apr 3;23(4):922-31. Epub 2012 Apr 3.

Brain Research Institute, University of Zürich/Swiss Federal Institute of Technology Zurich (ETHZ), 8057 Zürich, Switzerland.

The lateral ventricle (LV) of the adult rodent brain harbors neural stem cells (NSCs) that continue to generate new neurons throughout life. NSCs located in defined areas of the LV walls generate progenitors with distinct transcriptional profiles that are committed to specific neuronal fates. Here, we assessed if such diversity of NSCs also exist in the adult common marmoset, a widely used primate species in basic and clinical neuroscience research. We first investigated the 3D distributions of proliferative progenitors and committed neuroblasts in the marmoset forebrain. In addition to these maps, we assessed the spatial presence of divergent progenitor populations based on their expression of defined transcription factors, that is, Dlx2, Pax6, Tbr2, and Ngn2 which are differentially expressed by γ-aminobutyric acidergic versus glutamatergic progenitors in the adult rodent forebrain. In striking contrast to rodents, glutamatergic progenitors were only sparse in neonates and absent from the adult LV, whilst present in the hippocampus. Our analyses highlight major differences in the diversity of NSCs of the marmoset LV compared with rodents and emphasize the need to address NSCs diversity in evolutionary higher order mammals concomitantly to rodents.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/cercor/bhs085DOI Listing
April 2013

Targeted electroporation of defined lateral ventricular walls: a novel and rapid method to study fate specification during postnatal forebrain neurogenesis.

Neural Dev 2011 Apr 5;6:13. Epub 2011 Apr 5.

Brain Research Institute, University of Zürich/ETHZ, CH-8057 Zürich, Switzerland.

Background: Postnatal olfactory bulb (OB) neurogenesis involves the generation of granule and periglomerular cells by neural stem cells (NSCs) located in the walls of the lateral ventricle (LV). Recent studies show that NSCs located in different regions of the LV give rise to different types of OB neurons. However, the molecular mechanisms governing neuronal specification remain largely unknown and new methods to approach these questions are needed.

Results: In this study, we refine electroporation of the postnatal forebrain as a technique to perform precise and accurate delivery of transgenes to NSCs located in distinct walls of the LV in the mouse. Using this method, we confirm and expand previous studies showing that NSCs in distinct walls of the LV produce neurons that invade different layers of the OB. Fate mapping of the progeny of radial glial cells located in these distinct LV walls reveals their specification into defined subtypes of granule and periglomerular neurons.

Conclusions: Our results provide a baseline with which future studies aiming at investigating the role of factors in postnatal forebrain neuronal specification can be compared. Targeted electroporation of defined LV NSC populations will prove valuable to study the genetic factors involved in forebrain neuronal specification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1749-8104-6-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3098142PMC
April 2011