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Sawada K, Kamiya S, Kobayashi T. Neonatal Exposure to Lipopolysaccharide Promotes Neurogenesis of Subventricular Zone Progenitors in the Developing Neocortex of Ferrets. Int J Mol Sci 2023; 24:14962. [PMID: 37834410 PMCID: PMC10573966 DOI: 10.3390/ijms241914962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
Lipopolysaccharide (LPS) is a natural agonist of toll-like receptor 4 that serves a role in innate immunity. The current study evaluated the LPS-mediated regulation of neurogenesis in the subventricular zone (SVZ) progenitors, that is, the basal radial glia and intermediate progenitors (IPs), in ferrets. Ferret pups were subcutaneously injected with LPS (500 μg/g of body weight) on postnatal days (PDs) 6 and 7. Furthermore, 5-ethynyl-2'-deoxyuridine (EdU) and 5-bromo-2'-deoxyuridine (BrdU) were administered on PDs 5 and 7, respectively, to label the post-proliferative and proliferating cells in the inner SVZ (iSVZ) and outer SVZ (oSVZ). A significantly higher density of BrdU single-labeled proliferating cells was observed in the iSVZ of LPS-exposed ferrets than in controls but not in post-proliferative EdU single-labeled and EdU/BrdU double-labeled self-renewing cells. BrdU single-labeled cells exhibited a lower proportion of Tbr2 immunostaining in LPS-exposed ferrets (22.2%) than in controls (42.6%) and a higher proportion of Ctip2 immunostaining in LPS-exposed ferrets (22.2%) than in controls (8.6%). The present findings revealed that LPS modified the neurogenesis of SVZ progenitors. Neonatal LPS exposure facilitates the proliferation of SVZ progenitors, followed by the differentiation of Tbr2-expressing IPs into Ctip2-expressing immature neurons.
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Affiliation(s)
- Kazuhiko Sawada
- Department of Nutrition, Faculty of Medical and Health Sciences, Tsukuba International University, Tsuchiura 300-0051, Japan
| | - Shiori Kamiya
- Department of Regulation Biology, Faculty of Science, Saitama University, Saitama 338-8570, Japan; (S.K.); (T.K.)
| | - Tetsuya Kobayashi
- Department of Regulation Biology, Faculty of Science, Saitama University, Saitama 338-8570, Japan; (S.K.); (T.K.)
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2
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Rajan A, Ostgaard CM, Lee CY. Regulation of Neural Stem Cell Competency and Commitment during Indirect Neurogenesis. Int J Mol Sci 2021; 22:12871. [PMID: 34884676 PMCID: PMC8657492 DOI: 10.3390/ijms222312871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/24/2021] [Accepted: 11/24/2021] [Indexed: 11/29/2022] Open
Abstract
Indirect neurogenesis, during which neural stem cells generate neurons through intermediate progenitors, drives the evolution of lissencephalic brains to gyrencephalic brains. The mechanisms that specify intermediate progenitor identity and that regulate stem cell competency to generate intermediate progenitors remain poorly understood despite their roles in indirect neurogenesis. Well-characterized lineage hierarchy and available powerful genetic tools for manipulating gene functions make fruit fly neural stem cell (neuroblast) lineages an excellent in vivo paradigm for investigating the mechanisms that regulate neurogenesis. Type II neuroblasts in fly larval brains repeatedly undergo asymmetric divisions to generate intermediate neural progenitors (INPs) that undergo limited proliferation to increase the number of neurons generated per stem cell division. Here, we review key regulatory genes and the mechanisms by which they promote the specification and generation of INPs, safeguarding the indirect generation of neurons during fly larval brain neurogenesis. Homologs of these regulators of INPs have been shown to play important roles in regulating brain development in vertebrates. Insight into the precise regulation of intermediate progenitors will likely improve our understanding of the control of indirect neurogenesis during brain development and brain evolution.
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Affiliation(s)
- Arjun Rajan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
| | - Cyrina M. Ostgaard
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Division of Genetic Medicine, Department of Internal Medicine and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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3
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Girard JR, Goins LM, Vuu DM, Sharpley MS, Spratford CM, Mantri SR, Banerjee U. Paths and pathways that generate cell-type heterogeneity and developmental progression in hematopoiesis. eLife 2021; 10:e67516. [PMID: 34713801 PMCID: PMC8610493 DOI: 10.7554/elife.67516] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 10/22/2021] [Indexed: 12/29/2022] Open
Abstract
Mechanistic studies of Drosophila lymph gland hematopoiesis are limited by the availability of cell-type-specific markers. Using a combination of bulk RNA-Seq of FACS-sorted cells, single-cell RNA-Seq, and genetic dissection, we identify new blood cell subpopulations along a developmental trajectory with multiple paths to mature cell types. This provides functional insights into key developmental processes and signaling pathways. We highlight metabolism as a driver of development, show that graded Pointed expression allows distinct roles in successive developmental steps, and that mature crystal cells specifically express an alternate isoform of Hypoxia-inducible factor (Hif/Sima). Mechanistically, the Musashi-regulated protein Numb facilitates Sima-dependent non-canonical, and inhibits canonical, Notch signaling. Broadly, we find that prior to making a fate choice, a progenitor selects between alternative, biologically relevant, transitory states allowing smooth transitions reflective of combinatorial expressions rather than stepwise binary decisions. Increasingly, this view is gaining support in mammalian hematopoiesis.
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Affiliation(s)
- Juliet R Girard
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Lauren M Goins
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Dung M Vuu
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Mark S Sharpley
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Carrie M Spratford
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Shreya R Mantri
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Utpal Banerjee
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
- Molecular Biology Institute, University of California, Los AngelesLos AngelesUnited States
- Department of Biological Chemistry, University of California, Los AngelesLos AngelesUnited States
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los AngelesLos AngelesUnited States
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4
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Bedogni F, Hevner RF. Cell-Type-Specific Gene Expression in Developing Mouse Neocortex: Intermediate Progenitors Implicated in Axon Development. Front Mol Neurosci 2021; 14:686034. [PMID: 34321999 PMCID: PMC8313239 DOI: 10.3389/fnmol.2021.686034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/03/2021] [Indexed: 01/06/2023] Open
Abstract
Cerebral cortex projection neurons (PNs) are generated from intermediate progenitors (IPs), which are in turn derived from radial glial progenitors (RGPs). To investigate developmental processes in IPs, we profiled IP transcriptomes in embryonic mouse neocortex, using transgenic Tbr2-GFP mice, cell sorting, and microarrays. These data were used in combination with in situ hybridization to ascertain gene sets specific for IPs, RGPs, PNs, interneurons, and other neural and non-neural cell types. RGP-selective transcripts (n = 419) included molecules for Notch receptor signaling, proliferation, neural stem cell identity, apical junctions, necroptosis, hippo pathway, and NF-κB pathway. RGPs also expressed specific genes for critical interactions with meningeal and vascular cells. In contrast, IP-selective genes (n = 136) encoded molecules for activated Delta ligand presentation, epithelial-mesenchymal transition, core planar cell polarity (PCP), axon genesis, and intrinsic excitability. Interestingly, IPs expressed several “dependence receptors” (Unc5d, Dcc, Ntrk3, and Epha4) that induce apoptosis in the absence of ligand, suggesting a competitive mechanism for IPs and new PNs to detect key environmental cues or die. Overall, our results imply a novel role for IPs in the patterning of neuronal polarization, axon differentiation, and intrinsic excitability prior to mitosis. Significantly, IPs highly express Wnt-PCP, netrin, and semaphorin pathway molecules known to regulate axon polarization in other systems. In sum, IPs not only amplify neurogenesis quantitatively, but also molecularly “prime” new PNs for axogenesis, guidance, and excitability.
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Affiliation(s)
| | - Robert F Hevner
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
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5
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Tomita H, Cornejo F, Aranda-Pino B, Woodard CL, Rioseco CC, Neel BG, Alvarez AR, Kaplan DR, Miller FD, Cancino GI. The Protein Tyrosine Phosphatase Receptor Delta Regulates Developmental Neurogenesis. Cell Rep 2021; 30:215-228.e5. [PMID: 31914388 DOI: 10.1016/j.celrep.2019.11.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 10/10/2019] [Accepted: 11/07/2019] [Indexed: 12/26/2022] Open
Abstract
PTPRD is a receptor protein tyrosine phosphatase that is genetically associated with neurodevelopmental disorders. Here, we asked whether Ptprd mutations cause aberrant neural development by perturbing neurogenesis in the murine cortex. We show that loss of Ptprd causes increases in neurogenic transit-amplifying intermediate progenitor cells and cortical neurons and perturbations in neuronal localization. These effects are intrinsic to neural precursor cells since acute Ptprd knockdown causes similar perturbations. PTPRD mediates these effects by dephosphorylating receptor tyrosine kinases, including TrkB and PDGFRβ, and loss of Ptprd causes the hyperactivation of TrkB and PDGFRβ and their downstream MEK-ERK signaling pathway in neural precursor cells. Moreover, inhibition of aberrant TrkB or MEK activation rescues the increased neurogenesis caused by knockdown or homozygous loss of Ptprd. These results suggest that PTPRD regulates receptor tyrosine kinases to ensure appropriate numbers of intermediate progenitor cells and neurons, suggesting a mechanism for its genetic association with neurodevelopmental disorders.
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Affiliation(s)
- Hideaki Tomita
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto M5G 1X8, ON, Canada
| | - Francisca Cornejo
- Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago 8580745, Chile
| | - Begoña Aranda-Pino
- Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago 8580745, Chile
| | - Cameron L Woodard
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto M5G 1X8, ON, Canada
| | - Constanza C Rioseco
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto M5G 1X8, ON, Canada
| | - Benjamin G Neel
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA
| | - Alejandra R Alvarez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331010, Chile
| | - David R Kaplan
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto M5G 1X8, ON, Canada; Institute of Medical Science, University of Toronto, Toronto M5S 1A8, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, ON, Canada
| | - Freda D Miller
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto M5G 1X8, ON, Canada; Institute of Medical Science, University of Toronto, Toronto M5S 1A8, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, ON, Canada; Department of Physiology, University of Toronto, Toronto M5S 1A8, ON, Canada
| | - Gonzalo I Cancino
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto M5G 1X8, ON, Canada; Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago 8580745, Chile.
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6
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Rives-Quinto N, Komori H, Ostgaard CM, Janssens DH, Kondo S, Dai Q, Moore AW, Lee CY. Sequential activation of transcriptional repressors promotes progenitor commitment by silencing stem cell identity genes. eLife 2020; 9:e56187. [PMID: 33241994 PMCID: PMC7728440 DOI: 10.7554/elife.56187] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 11/25/2020] [Indexed: 12/21/2022] Open
Abstract
Stem cells that indirectly generate differentiated cells through intermediate progenitors drives vertebrate brain evolution. Due to a lack of lineage information, how stem cell functionality, including the competency to generate intermediate progenitors, becomes extinguished during progenitor commitment remains unclear. Type II neuroblasts in fly larval brains divide asymmetrically to generate a neuroblast and a progeny that commits to an intermediate progenitor (INP) identity. We identified Tailless (Tll) as a master regulator of type II neuroblast functional identity, including the competency to generate INPs. Successive expression of transcriptional repressors functions through Hdac3 to silence tll during INP commitment. Reducing repressor activity allows re-activation of Notch in INPs to ectopically induce tll expression driving supernumerary neuroblast formation. Knocking-down hdac3 function prevents downregulation of tll during INP commitment. We propose that continual inactivation of stem cell identity genes allows intermediate progenitors to stably commit to generating diverse differentiated cells during indirect neurogenesis.
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Affiliation(s)
| | - Hideyuki Komori
- Life Sciences Institute, University of MichiganAnn ArborUnited States
| | - Cyrina M Ostgaard
- Life Sciences Institute, University of MichiganAnn ArborUnited States
- Department of Cell and Developmental Biology, University of Michigan Medical SchoolAnn ArborUnited States
| | - Derek H Janssens
- Life Sciences Institute, University of MichiganAnn ArborUnited States
| | - Shu Kondo
- Invertebrate Genetics Laboratory, National Institute of GeneticsMishimaJapan
| | - Qi Dai
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm UniversityStockholmSweden
| | | | - Cheng-Yu Lee
- Life Sciences Institute, University of MichiganAnn ArborUnited States
- Department of Cell and Developmental Biology, University of Michigan Medical SchoolAnn ArborUnited States
- Division of Genetic Medicine, Department of Internal Medicine and Comprehensive Cancer Center, University of Michigan Medical SchoolAnn ArborUnited States
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7
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Dohare P, Kidwai A, Kaur J, Singla P, Krishna S, Klebe D, Zhang X, Hevner R, Ballabh P. GSK3β Inhibition Restores Impaired Neurogenesis in Preterm Neonates With Intraventricular Hemorrhage. Cereb Cortex 2020; 29:3482-3495. [PMID: 30192926 DOI: 10.1093/cercor/bhy217] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/30/2018] [Indexed: 01/25/2023] Open
Abstract
Intraventricular hemorrhage (IVH) is a common complication of prematurity in infants born at 23-28 weeks of gestation. Survivors exhibit impaired growth of the cerebral cortex and neurodevelopmental sequeale, but the underlying mechanism(s) are obscure. Previously, we have shown that neocortical neurogenesis continues until at least 28 gestational weeks. This renders the prematurely born infants vulnerable to impaired neurogenesis. Here, we hypothesized that neurogenesis is impaired by IVH, and that signaling through GSK3β, a critical intracellular kinase regulated by Wnt and other pathways, mediates this effect. These hypotheses were tested observationally in autopsy specimens from premature infants, and experimentally in a premature rabbit IVH model. Significantly, in premature infants with IVH, the number of neurogenic cortical progenitor cells was reduced compared with infants without IVH, indicating acutely decreased neurogenesis. This finding was corroborated in the rabbit IVH model, which further demonstrated reduction of upper layer cortical neurons after longer survival. Both the acute reduction of neurogenic progenitors, and the subsequent decrease of upper layer neurons, were rescued by treatment with AR-A014418, a specific inhibitor of GSK3β. Together, these results indicate that IVH impairs late stages of cortical neurogenesis, and suggest that treatment with GSK3β inhibitors may enhance neurodevelopment in premature infants with IVH.
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Affiliation(s)
- Preeti Dohare
- Department of Pediatrics.,Dominick P. Purpura Department of Neuroscience
| | | | | | | | | | | | | | - Robert Hevner
- Department of Pathology, 9500 Gilman Dr, UCSD, La Jolla, CA, USA
| | - Praveen Ballabh
- Department of Pediatrics.,Dominick P. Purpura Department of Neuroscience.,Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
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8
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Weng Q, Wang J, Wang J, He D, Cheng Z, Zhang F, Verma R, Xu L, Dong X, Liao Y, He X, Potter A, Zhang L, Zhao C, Xin M, Zhou Q, Aronow BJ, Blackshear PJ, Rich JN, He Q, Zhou W, Suvà ML, Waclaw RR, Potter SS, Yu G, Lu QR. Single-Cell Transcriptomics Uncovers Glial Progenitor Diversity and Cell Fate Determinants during Development and Gliomagenesis. Cell Stem Cell 2019; 24:707-723.e8. [PMID: 30982771 DOI: 10.1016/j.stem.2019.03.006] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 11/30/2018] [Accepted: 03/05/2019] [Indexed: 11/20/2022]
Abstract
The identity and degree of heterogeneity of glial progenitors and their contributions to brain tumor malignancy remain elusive. By applying lineage-targeted single-cell transcriptomics, we uncover an unanticipated diversity of glial progenitor pools with unique molecular identities in developing brain. Our analysis identifies distinct transitional intermediate states and their divergent developmental trajectories in astroglial and oligodendroglial lineages. Moreover, intersectional analysis uncovers analogous intermediate progenitors during brain tumorigenesis, wherein oligodendrocyte-progenitor intermediates are abundant, hyper-proliferative, and progressively reprogrammed toward a stem-like state susceptible to further malignant transformation. Similar actively cycling intermediate progenitors are prominent components in human gliomas with distinct driver mutations. We further unveil lineage-driving networks underlying glial fate specification and identify Zfp36l1 as necessary for oligodendrocyte-astrocyte lineage transition and glioma growth. Together, our results resolve the dynamic repertoire of common and divergent glial progenitors during development and tumorigenesis and highlight Zfp36l1 as a molecular nexus for balancing glial cell-fate decision and controlling gliomagenesis.
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9
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Abstract
In developing cerebral cortex, intermediate progenitors (IPs) are transit amplifying cells that specifically express Tbr2 (gene: Eomes), a T-box transcription factor. IPs are derived from radial glia (RG) progenitors, the neural stem cells of developing cortex. In turn, IPs generate glutamatergic projection neurons (PNs) exclusively. IPs are found in ventricular and subventricular zones, where they differentiate as distinct ventricular IP (vIP) and outer IP (oIP) subtypes. Morphologically, IPs have short processes, resembling filopodia or neurites, that transiently contact other cells, most importantly dividing RG cells to mediate Delta-Notch signaling. Also, IPs secrete a chemokine, Cxcl12, which guides interneuron and microglia migrations and promotes thalamocortical axon growth. In mice, IPs produce clones of 1-12 PNs, sometimes spanning multiple layers. After mitosis, IP daughter cells undergo asymmetric cell death in the majority of instances. In mice, Tbr2 is necessary for PN differentiation and subtype specification, and to repress IP-genic transcription factors. Tbr2 directly represses Insm1, an IP-genic transcription factor gene, as well as Pax6, a key activator of Tbr2 transcription. Without Tbr2, abnormal IPs transiently accumulate in elevated numbers. More broadly, Tbr2 regulates the transcriptome by activating or repressing hundreds of direct target genes. Notably, Tbr2 'unlocks' and activates PN-specific genes, such as Tbr1, by recruiting Jmjd3, a histone H3K27me3 demethylase that removes repressive epigenetic marks placed by polycomb repressive complex 2. IPs have played an important role in the evolution and gyrification of mammalian cerebral cortex, and TBR2 is essential for human brain development.
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Affiliation(s)
- Robert F Hevner
- Department of Pathology, University of California, San Diego, CA, USA
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10
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McIntosh R, Norris J, Clarke JD, Alexandre P. Spatial distribution and characterization of non-apical progenitors in the zebrafish embryo central nervous system. Open Biol 2017; 7:rsob.160312. [PMID: 28148823 PMCID: PMC5356445 DOI: 10.1098/rsob.160312] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/21/2016] [Indexed: 11/24/2022] Open
Abstract
Studies of non-apical progenitors (NAPs) have been largely limited to the developing mammalian cortex. They are postulated to generate the increase in neuron numbers that underlie mammalian brain expansion. Recently, NAPs have also been reported in the retina and central nervous system of non-mammalian species; in the latter, however, they remain poorly characterized. Here, we characterize NAP location along the zebrafish central nervous system during embryonic development, and determine their cellular and molecular characteristics and renewal capacity. We identified a small population of NAPs in the spinal cord, hindbrain and telencephalon of zebrafish embryos. Live-imaging analysis revealed at least two types of mitotic behaviour in the telencephalon: one NAP subtype retains the apical attachment during division, while another divides in a subapical position disconnected from the apical surface. All NAPs observed in spinal cord lost apical contact prior to mitoses. These NAPs express HuC and produce two neurons from a single division. Manipulation of Notch activity reveals that neurons and NAPs in the spinal cord use similar regulatory mechanisms. This work suggests that the majority of spinal NAPs in zebrafish share characteristics with basal progenitors in mammalian brains.
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Affiliation(s)
- Rebecca McIntosh
- Developmental Biology and Cancer Department, UCL Institute of Child Health, London WC1N 1EH, UK.,Division of Surgery and Interventional Science, University College London, London, UK
| | - Joseph Norris
- Division of Surgery and Interventional Science, University College London, London, UK
| | - Jon D Clarke
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Paula Alexandre
- Developmental Biology and Cancer Department, UCL Institute of Child Health, London WC1N 1EH, UK
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11
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Moreno N, González A. Pattern of Neurogenesis and Identification of Neuronal Progenitor Subtypes during Pallial Development in Xenopus laevis. Front Neuroanat 2017; 11:24. [PMID: 28396626 PMCID: PMC5366753 DOI: 10.3389/fnana.2017.00024] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/08/2017] [Indexed: 11/13/2022] Open
Abstract
The complexity of the pallium during evolution has increased dramatically in many different respects. The highest level of complexity is found in mammals, where most of the pallium (cortex) shows a layered organization and neurons are generated during development following an inside-out order, a sequence not observed in other amniotes (birds and reptiles). Species-differences may be related to major neurogenetic events, from the neural progenitors that divide and produce all pallial cells. In mammals, two main types of precursors have been described, primary precursor cells in the ventricular zone (vz; also called radial glial cells or apical progenitors) and secondary precursor cells (called basal or intermediate progenitors) separated from the ventricle surface. Previous studies suggested that pallial neurogenetic cells, and especially the intermediate progenitors, evolved independently in mammalian and sauropsid lineages. In the present study, we examined pallial neurogenesis in the amphibian Xenopus laevis, a representative species of the only group of tetrapods that are anamniotes. The pattern of pallial proliferation during embryonic and larval development was studied, together with a multiple immunohistochemical analysis of putative progenitor cells. We found that there are two phases of progenitor divisions in the developing pallium that, following the radial unit concept from the ventricle to the mantle, finally result in an outside-in order of mature neurons, what seems to be the primitive condition of vertebrates. Gene expressions of key transcription factors that characterize radial glial cells in the vz were demonstrated in Xenopus. In addition, although mitotic cells were corroborated outside the vz, the expression pattern of markers for intermediate progenitors differed from mammals.
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Affiliation(s)
- Nerea Moreno
- Department of Cell Biology, Faculty of Biology, Complutense University of Madrid Madrid, Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, Complutense University of Madrid Madrid, Spain
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12
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Abstract
p63 is a member of the p53 family that regulates the survival of neural precursors in the adult brain. However, the relative importance of p63 in the developing brain is still unclear, since embryonic p63−/− mice display no apparent deficits in neural development. Here, we have used a more definitive conditional knockout mouse approach to address this issue, crossing p63fl/fl mice to mice carrying a nestin-CreERT2 transgene that drives inducible recombination in neural precursors following tamoxifen treatment. Inducible ablation of p63 following tamoxifen treatment of mice on embryonic day 12 resulted in highly perturbed forebrain morphology including a thinner cortex and enlarged lateral ventricles 3 d later. While the normal cortical layers were still present following acute p63 ablation, cortical precursors and neurons were both reduced in number due to widespread cellular apoptosis. This apoptosis was cell-autonomous, since it also occurred when p63 was inducibly ablated in primary cultured cortical precursors. Finally, we demonstrate increased expression of the mRNA encoding another p53 family member, ΔNp73, in cortical precursors of p63−/− but not tamoxifen-treated p63fl/fl;R26YFPfl/fl;nestin-CreERT2+/Ø embryos. Since ΔNp73 promotes cell survival, then this compensatory increase likely explains the lack of an embryonic brain phenotype in p63−/− mice. Thus, p63 plays a key prosurvival role in the developing mammalian brain.
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Affiliation(s)
- Gonzalo I Cancino
- a Program in Neurosciences and Mental Health, Hospital for Sick Children ; Toronto , ON Canada
| | - Michael P Fatt
- a Program in Neurosciences and Mental Health, Hospital for Sick Children ; Toronto , ON Canada.,b Institute of Medical Science, University of Toronto ; Toronto , ON Canada
| | - Freda D Miller
- a Program in Neurosciences and Mental Health, Hospital for Sick Children ; Toronto , ON Canada.,b Institute of Medical Science, University of Toronto ; Toronto , ON Canada.,c Departments of Physiology ; University of Toronto ; Toronto , ON Canada.,d Molecular Genetics, University of Toronto ; Toronto , ON Canada
| | - David R Kaplan
- a Program in Neurosciences and Mental Health, Hospital for Sick Children ; Toronto , ON Canada.,b Institute of Medical Science, University of Toronto ; Toronto , ON Canada.,d Molecular Genetics, University of Toronto ; Toronto , ON Canada
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13
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López Tobón A, Shah B. Commentary: Coordinating Thalamocortical Connections and Interneuron Migration in the Mammalian Cortex: Role of the Intermediates. Front Cell Neurosci 2016; 10:82. [PMID: 27065806 PMCID: PMC4814548 DOI: 10.3389/fncel.2016.00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/16/2016] [Indexed: 11/13/2022] Open
Affiliation(s)
- Alejandro López Tobón
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-UniversitätMünster, Germany; Department of Experimental Oncology, European Institute of Oncology (IEO), Institute of Molecular Oncology Foundation and European Institute of Oncology Campus (IFOM-IEO Campus)Milan, Italy
| | - Bhavin Shah
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Germany
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Montiel JF, Vasistha NA, Garcia-Moreno F, Molnár Z. From sauropsids to mammals and back: New approaches to comparative cortical development. J Comp Neurol 2016; 524:630-45. [PMID: 26234252 PMCID: PMC4832283 DOI: 10.1002/cne.23871] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/21/2015] [Accepted: 07/21/2015] [Indexed: 01/31/2023]
Abstract
Evolution of the mammalian neocortex (isocortex) has been a persisting problem in neurobiology. While recent studies have attempted to understand the evolutionary expansion of the human neocortex from rodents, similar approaches have been used to study the changes between reptiles, birds, and mammals. We review here findings from the past decades on the development, organization, and gene expression patterns in various extant species. This review aims to compare cortical cell numbers and neuronal cell types to the elaboration of progenitor populations and their proliferation in these species. Several progenitors, such as the ventricular radial glia, the subventricular intermediate progenitors, and the subventricular (outer) radial glia, have been identified but the contribution of each to cortical layers and cell types through specific lineages, their possible roles in determining brain size or cortical folding, are not yet understood. Across species, larger, more diverse progenitors relate to cortical size and cell diversity. The challenge is to relate the radial and tangential expansion of the neocortex to the changes in the proliferative compartments during mammalian evolution and with the changes in gene expression and lineages evident in various sectors of the developing brain. We also review the use of recent lineage tracing and transcriptomic approaches to revisit theories and to provide novel understanding of molecular processes involved in specification of cortical regions.
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Affiliation(s)
- Juan F Montiel
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Centre for Biomedical Research, Facultad de Medicina, Universidad Diego Portales, Santiago, Chile
| | - Navneet A Vasistha
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Scotland, UK
| | | | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Vasistha NA, García-Moreno F, Arora S, Cheung AFP, Arnold SJ, Robertson EJ, Molnár Z. Cortical and Clonal Contribution of Tbr2 Expressing Progenitors in the Developing Mouse Brain. Cereb Cortex 2014; 25:3290-302. [PMID: 24927931 PMCID: PMC4585488 DOI: 10.1093/cercor/bhu125] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The individual contribution of different progenitor subtypes towards the mature rodent cerebral cortex is not fully understood. Intermediate progenitor cells (IPCs) are key to understanding the regulation of neuronal number during cortical development and evolution, yet their exact contribution is much debated. Intermediate progenitors in the cortical subventricular zone are defined by expression of T-box brain-2 (Tbr2). In this study we demonstrate by using the Tbr2(Cre) mouse line and state-of-the-art cell lineage labeling techniques, that IPC derived cells contribute substantial proportions 67.5% of glutamatergic but not GABAergic or astrocytic cells to all cortical layers including the earliest generated subplate zone. We also describe the laminar dispersion of clonally derived cells from IPCs using a recently described clonal analysis tool (CLoNe) and show that pair-generated cells in different layers cluster closer (142.1 ± 76.8 μm) than unrelated cells (294.9 ± 105.4 μm). The clonal dispersion from individual Tbr2 positive intermediate progenitors contributes to increasing the cortical surface. Our study also describes extracortical contributions from Tbr2+ progenitors to the lateral olfactory tract and ventromedial hypothalamic nucleus.
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Affiliation(s)
- Navneet A Vasistha
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Siddharth Arora
- Oxford Centre for Industrial and Applied Mathematics (OCIAM), University of Oxford, 24-29 St Giles', Oxford, UK
| | - Amanda F P Cheung
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Sebastian J Arnold
- Renal Department, University Medical Centre, Centre for Clinical Research, Breisacher Strasse 66, 79106 Freiburg, Germany BIOSS Centre of Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | | | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Abstract
The anatomical organization of the mammalian neocortex stands out among vertebrates for its laminar and columnar arrangement, featuring vertically oriented, excitatory pyramidal neurons. The evolutionary origin of this structure is discussed here in relation to the brain organization of other amniotes, i.e., the sauropsids (reptiles and birds). Specifically, we address the developmental modifications that had to take place to generate the neocortex, and to what extent these modifications were shared by other amniote lineages or can be considered unique to mammals. In this article, we propose a hypothesis that combines the control of proliferation in neural progenitor pools with the specification of regional morphogenetic gradients, yielding different anatomical results by virtue of the differential modulation of these processes in each lineage. Thus, there is a highly conserved genetic and developmental battery that becomes modulated in different directions according to specific selective pressures. In the case of early mammals, ecological conditions like nocturnal habits and reproductive strategies are considered to have played a key role in the selection of the particular brain patterning mechanisms that led to the origin of the neocortex.
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Affiliation(s)
- Francisco Aboitiz
- Departamento de Psiquiatría, Facultad de Medicina y Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile Santiago, Chile
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