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Rubenstein JL, Nord AS, Ekker M. DLX genes and proteins in mammalian forebrain development. Development 2024; 151:dev202684. [PMID: 38819455 PMCID: PMC11190439 DOI: 10.1242/dev.202684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
The vertebrate Dlx gene family encode homeobox transcription factors that are related to the Drosophila Distal-less (Dll) gene and are crucial for development. Over the last ∼35 years detailed information has accrued about the redundant and unique expression and function of the six mammalian Dlx family genes. DLX proteins interact with general transcriptional regulators, and co-bind with other transcription factors to enhancer elements with highly specific activity in the developing forebrain. Integration of the genetic and biochemical data has yielded a foundation for a gene regulatory network governing the differentiation of forebrain GABAergic neurons. In this Primer, we describe the discovery of vertebrate Dlx genes and their crucial roles in embryonic development. We largely focus on the role of Dlx family genes in mammalian forebrain development revealed through studies in mice. Finally, we highlight questions that remain unanswered regarding vertebrate Dlx genes despite over 30 years of research.
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Affiliation(s)
- John L. Rubenstein
- UCSF Department of Psychiatry and Behavioral Sciences, Department of UCSF Weill Institute for Neurosciences, Nina Ireland Laboratory of Developmental Neurobiology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Alex S. Nord
- Department of Neurobiology, Physiology, and Behavior and Department of Psychiatry and 20 Behavioral Sciences, Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - Marc Ekker
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
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Altbürger C, Rath M, Wehrle J, Driever W. The proneural factors Ascl1a and Ascl1b contribute to the terminal differentiation of dopaminergic GABAergic dual transmitter neurons in zebrafish. Dev Biol 2024; 505:58-74. [PMID: 37931393 DOI: 10.1016/j.ydbio.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 10/06/2023] [Accepted: 10/23/2023] [Indexed: 11/08/2023]
Abstract
The proneural factor Ascl1 is involved in several steps of neurogenesis, from neural progenitor maintenance to initiation of terminal differentiation and neuronal subtype specification. In neural progenitor cells, Ascl1 initiates the cell-cycle exit of progenitors, and contributes to their differentiation into mainly GABAergic neurons. Several catecholaminergic neuron groups in the forebrain of zebrafish use GABA as co-transmitter, but a potential role of the two paralogues Ascl1a and Ascl1b in their neurogenesis is not understood. Here, we show that ascl1a, ascl1b double mutant embryos develop a significantly reduced number of neurons in all GABAergic and catecholaminergic dual transmitter neuron anatomical clusters in the fore- and hindbrain, while glutamatergic catecholaminergic clusters develop normally. However, none of the affected catecholaminergic cell clusters are lost completely, suggesting an impairment in progenitor pools, or a requirement of Ascl1a/b for differentiation of a subset of neurons in each cluster. Early progenitors which are dlx2a+, fezf2 + or emx2 + are not reduced whereas late progenitors and differentiating neurons marked by the expression of dlx5a, isl1 and arxa are severely reduced in ascl1a, ascl1b double mutant embryos. This suggests that Ascl1a and Ascl1b play only a minor or no role in the maintenance of their progenitor pools, but rather contribute to the initiation of terminal differentiation of GABAergic catecholaminergic neurons.
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Affiliation(s)
- Christian Altbürger
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany; CIBSS and BIOSS - Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany
| | - Meta Rath
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany
| | - Johanna Wehrle
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany; MeInBio Research Training Group, University of Freiburg, 79104, Freiburg, Germany
| | - Wolfgang Driever
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany; CIBSS and BIOSS - Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany.
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Toudji I, Toumi A, Chamberland É, Rossignol E. Interneuron odyssey: molecular mechanisms of tangential migration. Front Neural Circuits 2023; 17:1256455. [PMID: 37779671 PMCID: PMC10538647 DOI: 10.3389/fncir.2023.1256455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/21/2023] [Indexed: 10/03/2023] Open
Abstract
Cortical GABAergic interneurons are critical components of neural networks. They provide local and long-range inhibition and help coordinate network activities involved in various brain functions, including signal processing, learning, memory and adaptative responses. Disruption of cortical GABAergic interneuron migration thus induces profound deficits in neural network organization and function, and results in a variety of neurodevelopmental and neuropsychiatric disorders including epilepsy, intellectual disability, autism spectrum disorders and schizophrenia. It is thus of paramount importance to elucidate the specific mechanisms that govern the migration of interneurons to clarify some of the underlying disease mechanisms. GABAergic interneurons destined to populate the cortex arise from multipotent ventral progenitor cells located in the ganglionic eminences and pre-optic area. Post-mitotic interneurons exit their place of origin in the ventral forebrain and migrate dorsally using defined migratory streams to reach the cortical plate, which they enter through radial migration before dispersing to settle in their final laminar allocation. While migrating, cortical interneurons constantly change their morphology through the dynamic remodeling of actomyosin and microtubule cytoskeleton as they detect and integrate extracellular guidance cues generated by neuronal and non-neuronal sources distributed along their migratory routes. These processes ensure proper distribution of GABAergic interneurons across cortical areas and lamina, supporting the development of adequate network connectivity and brain function. This short review summarizes current knowledge on the cellular and molecular mechanisms controlling cortical GABAergic interneuron migration, with a focus on tangential migration, and addresses potential avenues for cell-based interneuron progenitor transplants in the treatment of neurodevelopmental disorders and epilepsy.
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Affiliation(s)
- Ikram Toudji
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Asmaa Toumi
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada
| | - Émile Chamberland
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Elsa Rossignol
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
- Department of Pediatrics, Université de Montréal, Montréal, QC, Canada
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Galante C, Marichal N, Scarante FF, Ghayad LM, Shi Y, Schuurmans C, Berninger B, Péron S. Enhanced proliferation of oligodendrocyte progenitor cells following retrovirus mediated Achaete-scute complex-like 1 overexpression in the postnatal cerebral cortex in vivo. Front Neurosci 2022; 16:919462. [PMID: 36532282 PMCID: PMC9755855 DOI: 10.3389/fnins.2022.919462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
The proneural transcription factor Achaete-scute complex-like 1 (Ascl1) is a major regulator of neural fate decisions, implicated both in neurogenesis and oligodendrogliogenesis. Focusing on its neurogenic activity, Ascl1 has been widely used to reprogram non-neuronal cells into induced neurons. In vitro, Ascl1 induces efficient reprogramming of proliferative astroglia from the early postnatal cerebral cortex into interneuron-like cells. Here, we examined whether Ascl1 can similarly induce neuronal reprogramming of glia undergoing proliferation in the postnatal mouse cerebral cortex in vivo. Toward this goal, we targeted cortical glia during the peak of proliferative expansion (i.e., postnatal day 5) by injecting a retrovirus encoding for Ascl1 into the mouse cerebral cortex. In contrast to the efficient reprogramming observed in vitro, in vivo Ascl1-transduced glial cells were converted into doublecortin-immunoreactive neurons only with very low efficiency. However, we noted a drastic shift in the relative number of retrovirus-transduced Sox10-positive oligodendrocyte progenitor cells (OPCs) as compared to glial fibrillary acidic protein (GFAP)-positive astrocytes. Genetic fate mapping demonstrated that this increase in OPCs was not due to Ascl1-mediated astrocyte-to-OPC fate conversion. Rather, EdU incorporation experiments revealed that Ascl1 caused a selective increase in proliferative activity of OPCs, but not astrocytes. Our data indicate that rather than inducing neuronal reprogramming of glia in the early postnatal cortex, Ascl1 is a selective enhancer of OPC proliferation.
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Affiliation(s)
- Chiara Galante
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany
| | - Nicolás Marichal
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
| | - Franciele Franco Scarante
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom,Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Litsa Maria Ghayad
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
| | - Youran Shi
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom,The Francis Crick Institute, London, United Kingdom
| | - Carol Schuurmans
- Biological Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada,Department of Biochemistry, University of Toronto, Toronto, ON, Canada,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Benedikt Berninger
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany,Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom,The Francis Crick Institute, London, United Kingdom,MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom,Focus Program Translational Neuroscience, Johannes Gutenberg University, Mainz, Germany,Benedikt Berninger,
| | - Sophie Péron
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany,Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom,*Correspondence: Sophie Péron,
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Lee DG, Kim YK, Baek KH. The bHLH Transcription Factors in Neural Development and Therapeutic Applications for Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms232213936. [PMID: 36430421 PMCID: PMC9696289 DOI: 10.3390/ijms232213936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
The development of functional neural circuits in the central nervous system (CNS) requires the production of sufficient numbers of various types of neurons and glial cells, such as astrocytes and oligodendrocytes, at the appropriate periods and regions. Hence, severe neuronal loss of the circuits can cause neurodegenerative diseases such as Huntington's disease (HD), Parkinson's disease (PD), Alzheimer's disease (AD), and Amyotrophic Lateral Sclerosis (ALS). Treatment of such neurodegenerative diseases caused by neuronal loss includes some strategies of cell therapy employing stem cells (such as neural progenitor cells (NPCs)) and gene therapy through cell fate conversion. In this report, we review how bHLH acts as a regulator in neuronal differentiation, reprogramming, and cell fate determination. Moreover, several different researchers are conducting studies to determine the importance of bHLH factors to direct neuronal and glial cell fate specification and differentiation. Therefore, we also investigated the limitations and future directions of conversion or transdifferentiation using bHLH factors.
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Affiliation(s)
- Dong Gi Lee
- Joint Section of Science in Environmental Technology, Food Technology, and Molecular Biotechnology, Ghent University, Incheon 21569, Korea
| | - Young-Kwang Kim
- Department of Biomedical Science, CHA Stem Cell Institute, CHA University, Seongnam 13488, Korea
| | - Kwang-Hyun Baek
- Department of Biomedical Science, CHA Stem Cell Institute, CHA University, Seongnam 13488, Korea
- Correspondence: ; Tel.: +82-31-881-7134
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Leung RF, George AM, Roussel EM, Faux MC, Wigle JT, Eisenstat DD. Genetic Regulation of Vertebrate Forebrain Development by Homeobox Genes. Front Neurosci 2022; 16:843794. [PMID: 35546872 PMCID: PMC9081933 DOI: 10.3389/fnins.2022.843794] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/14/2022] [Indexed: 01/19/2023] Open
Abstract
Forebrain development in vertebrates is regulated by transcription factors encoded by homeobox, bHLH and forkhead gene families throughout the progressive and overlapping stages of neural induction and patterning, regional specification and generation of neurons and glia from central nervous system (CNS) progenitor cells. Moreover, cell fate decisions, differentiation and migration of these committed CNS progenitors are controlled by the gene regulatory networks that are regulated by various homeodomain-containing transcription factors, including but not limited to those of the Pax (paired), Nkx, Otx (orthodenticle), Gsx/Gsh (genetic screened), and Dlx (distal-less) homeobox gene families. This comprehensive review outlines the integral role of key homeobox transcription factors and their target genes on forebrain development, focused primarily on the telencephalon. Furthermore, links of these transcription factors to human diseases, such as neurodevelopmental disorders and brain tumors are provided.
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Affiliation(s)
- Ryan F. Leung
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Ankita M. George
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Enola M. Roussel
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Maree C. Faux
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Jeffrey T. Wigle
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - David D. Eisenstat
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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Fazel Darbandi S, Esau C, Lesage-Pelletier C, Monis S, Poitras L, Yu M, Perin S, Hatch G, Ekker M. Increased Sociability in Mice Lacking Intergenic Dlx Enhancers. Front Neurosci 2021; 15:718948. [PMID: 34671237 PMCID: PMC8520905 DOI: 10.3389/fnins.2021.718948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/10/2021] [Indexed: 11/13/2022] Open
Abstract
The Dlx homeodomain transcription factors play important roles in the differentiation and migration of GABAergic interneuron precursors. The mouse and human genomes each have six Dlx genes organized into three convergently transcribed bigene clusters (Dlx1/2, Dlx3/4, and Dlx5/6) with cis-regulatory elements (CREs) located in the intergenic region of each cluster. Amongst these, the I56i and I12b enhancers from the Dlx1/2 and Dlx5/6 locus, respectively, are active in the developing forebrain. I56i is also a binding site for GTF2I, a transcription factor whose function is associated with increased sociability and Williams-Beuren syndrome. In determining the regulatory roles of these CREs on forebrain development, we have generated mutant mouse-lines where Dlx forebrain intergenic enhancers have been deleted (I56i(-/-), I12b(-/-)). Loss of Dlx intergenic enhancers impairs expression of Dlx genes as well as some of their downstream targets or associated genes including Gad2 and Evf2. The loss of the I56i enhancer resulted in a transient decrease in GABA+ cells in the developing forebrain. The intergenic enhancer mutants also demonstrate increased sociability and learning deficits in a fear conditioning test. Characterizing mice with mutated Dlx intergenic enhancers will help us to further enhance our understanding of the role of these Dlx genes in forebrain development.
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Affiliation(s)
| | - Crystal Esau
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | | | - Simon Monis
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Luc Poitras
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Man Yu
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Sofia Perin
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Gary Hatch
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Marc Ekker
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
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Yu EPY, Perin S, Saxena V, Ekker M. Novel cross-regulation interactions between dlx genes in larval zebrafish. Gene 2021; 801:145848. [PMID: 34293450 DOI: 10.1016/j.gene.2021.145848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/13/2021] [Indexed: 11/19/2022]
Abstract
The homeodomain-containing transcription factors dlx1a, dlx2a, dlx5a and dlx6a are expressed in the zebrafish brain in overlapping patterns and are important in vertebrate development. Previous work in mice have suggested the overlapping expression pattern is in part due to cross-regulatory interactions among the aforementioned dlx genes. However, the extent of these interactions and whether they are conserved among vertebrates remains to be determined. Through whole-mount in situ hybridization in zebrafish dlx mutants produced by CRISPR-Cas9 mutagenesis, cross-regulatory interactions between dlx1a, dlx2a, dlx5a and dlx6a were examined from 24 to 72 h post fertilization (hpf). Notably, and different from previous work done in mouse, zebrafish dlx2a-/- mutants continue to express dlx5a until 72hpf, whereas deletion of both enhancers within the dlx5a/dlx6a locus resulted in delayed dlx5a/dlx6a expression and relative increased dlx2a expression. These results suggest alternative regulatory elements and pathways exist to mediate dlx expression in zebrafish and may highlight evolutionary differences in gene interactions between vertebrates.
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Affiliation(s)
- Emily P Y Yu
- Department of Biology, University of Ottawa, Marie-Curie Private, Ottawa, ON K1N9A4, Canada
| | - Sofia Perin
- Department of Biology, University of Ottawa, Marie-Curie Private, Ottawa, ON K1N9A4, Canada
| | - Vishal Saxena
- Department of Biology, University of Ottawa, Marie-Curie Private, Ottawa, ON K1N9A4, Canada
| | - Marc Ekker
- Department of Biology, University of Ottawa, Marie-Curie Private, Ottawa, ON K1N9A4, Canada.
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DLX Genes: Roles in Development and Cancer. Cancers (Basel) 2021; 13:cancers13123005. [PMID: 34203994 PMCID: PMC8232755 DOI: 10.3390/cancers13123005] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/14/2022] Open
Abstract
Simple Summary DLX homeobox family genes encode transcription factors that have indispensable roles in embryonic and postnatal development. These genes are critically linked to the morphogenesis of craniofacial structures, branchial arches, forebrain, and sensory organs. DLX genes are also involved in postnatal homeostasis, particularly hematopoiesis and, when dysregulated, oncogenesis. DLX1/2, DLX3/4, and DLX5/6 exist as bigenes on different chromosomes, sharing intergenic enhancers between gene pairs, which allows orchestrated spatiotemporal expression. Genomic alterations of human DLX gene enhancers or coding sequences result in congenital disorders such as split-hand/foot malformation. Aberrant postnatal expression of DLX genes is associated with hematological malignancies, including leukemias and lymphomas. In several mouse models of T-cell lymphoma, Dlx5 has been shown to act as an oncogene by cooperating with activated Akt, Notch1/3, and/or Wnt to drive tumor formation. In humans, DLX5 is aberrantly expressed in lung and ovarian carcinomas and holds promise as a therapeutic target. Abstract Homeobox genes control body patterning and cell-fate decisions during development. The homeobox genes consist of many families, only some of which have been investigated regarding a possible role in tumorigenesis. Dysregulation of HOX family genes have been widely implicated in cancer etiology. DLX homeobox genes, which belong to the NK-like family, exert dual roles in development and cancer. The DLX genes are the key transcription factors involved in regulating the development of craniofacial structures in vertebrates. The three DLX bigenes have overlapping expression in the branchial arches. Disruption of DLX function has destructive consequences in organogenesis and is associated with certain congenital disorders in humans. The role of DLX genes in oncogenesis is only beginning to emerge. DLX2 diminishes cellular senescence by regulating p53 function, whereas DLX4 has been associated with metastasis in breast cancer. In human ovarian cancer cells, DLX5 is essential for regulating AKT signaling, thereby promoting cell proliferation and survival. We previously implicated Dlx5 as an oncogene in murine T-cell lymphoma driven by a constitutively active form of Akt2. In this mouse model, overexpression of Dlx5 was caused by a chromosomal rearrangement that juxtaposed the Tcr-beta promoter region near the Dlx5 locus. Moreover, transgenic mice overexpressing Dlx5, specifically in immature T-cells, develop spontaneous thymic lymphomas. Oncogenesis in this mouse model involves binding of Dlx5 to the Notch1 and Notch3 gene loci to activate their transcription. Dlx5 also cooperates with Akt signaling to accelerate lymphomagenesis by activating Wnt signaling. We also discuss the fact that human DLX5 is aberrantly expressed in several human malignancies.
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Boshans LL, Soh H, Wood WM, Nolan TM, Mandoiu II, Yanagawa Y, Tzingounis AV, Nishiyama A. Direct reprogramming of oligodendrocyte precursor cells into GABAergic inhibitory neurons by a single homeodomain transcription factor Dlx2. Sci Rep 2021; 11:3552. [PMID: 33574458 PMCID: PMC7878775 DOI: 10.1038/s41598-021-82931-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
Oligodendrocyte precursor cells (NG2 glia) are uniformly distributed proliferative cells in the mammalian central nervous system and generate myelinating oligodendrocytes throughout life. A subpopulation of OPCs in the neocortex arises from progenitor cells in the embryonic ganglionic eminences that also produce inhibitory neurons. The neuronal fate of some progenitor cells is sealed before birth as they become committed to the oligodendrocyte lineage, marked by sustained expression of the oligodendrocyte transcription factor Olig2, which represses the interneuron transcription factor Dlx2. Here we show that misexpression of Dlx2 alone in postnatal mouse OPCs caused them to switch their fate to GABAergic neurons within 2 days by downregulating Olig2 and upregulating a network of inhibitory neuron transcripts. After two weeks, some OPC-derived neurons generated trains of action potentials and formed clusters of GABAergic synaptic proteins. Our study revealed that the developmental molecular logic can be applied to promote neuronal reprogramming from OPCs.
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Affiliation(s)
- Linda L Boshans
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - William M Wood
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Timothy M Nolan
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Ion I Mandoiu
- Department of Computer Science and Engineering, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | | | - Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA.
- The Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA.
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A Simple Differentiation Protocol for Generation of Induced Pluripotent Stem Cell-Derived Basal Forebrain-Like Cholinergic Neurons for Alzheimer's Disease and Frontotemporal Dementia Disease Modeling. Cells 2020; 9:cells9092018. [PMID: 32887382 PMCID: PMC7564334 DOI: 10.3390/cells9092018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/20/2020] [Accepted: 08/29/2020] [Indexed: 12/20/2022] Open
Abstract
The study of neurodegenerative diseases using pluripotent stem cells requires new methods to assess neurodevelopment and neurodegeneration of specific neuronal subtypes. The cholinergic system, characterized by its use of the neurotransmitter acetylcholine, is one of the first to degenerate in Alzheimer’s disease and is also affected in frontotemporal dementia. We developed a differentiation protocol to generate basal forebrain-like cholinergic neurons (BFCNs) from induced pluripotent stem cells (iPSCs) aided by the use of small molecule inhibitors and growth factors. Ten iPSC lines were successfully differentiated into BFCNs using this protocol. The neuronal cultures were characterised through RNA and protein expression, and functional analysis of neurons was confirmed by whole-cell patch clamp. We have developed a reliable protocol using only small molecule inhibitors and growth factors, while avoiding transfection or cell sorting methods, to achieve a BFCN culture that expresses the characteristic markers of cholinergic neurons.
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Aslanpour S, Rosin JM, Balakrishnan A, Klenin N, Blot F, Gradwohl G, Schuurmans C, Kurrasch DM. Ascl1 is required to specify a subset of ventromedial hypothalamic neurons. Development 2020; 147:dev180067. [PMID: 32253239 DOI: 10.1242/dev.180067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 03/23/2020] [Indexed: 03/01/2024]
Abstract
Despite clear physiological roles, the ventromedial hypothalamus (VMH) developmental programs are poorly understood. Here, we asked whether the proneural gene achaete-scute homolog 1 (Ascl1) contributes to VMH development. Ascl1 transcripts were detected in embryonic day (E) 10.5 to postnatal day 0 VMH neural progenitors. The elimination of Ascl1 reduced the number of VMH neurons at E12.5 and E15.5, particularly within the VMH-central (VMHC) and -dorsomedial (VMHDM) subdomains, and resulted in a VMH cell fate change from glutamatergic to GABAergic. We observed a loss of Neurog3 expression in Ascl1-/- hypothalamic progenitors and an upregulation of Neurog3 when Ascl1 was overexpressed. We also demonstrated a glutamatergic to GABAergic fate switch in Neurog3-null mutant mice, suggesting that Ascl1 might act via Neurog3 to drive VMH cell fate decisions. We also showed a concomitant increase in expression of the central GABAergic fate determinant Dlx1/2 in the Ascl1-null hypothalamus. However, Ascl1 was not sufficient to induce an ectopic VMH fate when overexpressed outside the normal window of competency. Combined, Ascl1 is required but not sufficient to specify the neurotransmitter identity of VMH neurons, acting in a transcriptional cascade with Neurog3.
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Affiliation(s)
- Shaghayegh Aslanpour
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jessica M Rosin
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Anjali Balakrishnan
- Sunnybrook Research Institute, Department of Biochemistry, University of Toronto, ON M4N 3M5, Canada
| | - Natalia Klenin
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Florence Blot
- Department of Development and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM, Universite de Strasbourg, Illkirch 67400, France
| | - Gerard Gradwohl
- Department of Development and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM, Universite de Strasbourg, Illkirch 67400, France
| | - Carol Schuurmans
- Sunnybrook Research Institute, Department of Biochemistry, University of Toronto, ON M4N 3M5, Canada
| | - Deborah M Kurrasch
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
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13
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Barretto N, Zhang H, Powell SK, Fernando MB, Zhang S, Flaherty EK, Ho SM, Slesinger PA, Duan J, Brennand KJ. ASCL1- and DLX2-induced GABAergic neurons from hiPSC-derived NPCs. J Neurosci Methods 2020; 334:108548. [PMID: 32065989 PMCID: PMC7426253 DOI: 10.1016/j.jneumeth.2019.108548] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 11/28/2019] [Accepted: 12/10/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Somatic cell reprogramming is routinely used to generate donor-specific human induced pluripotent stem cells (hiPSCs) to facilitate studies of disease in a human context. The directed differentiation of hiPSCs can generate large quantities of patient-derived cells; however, such methodologies frequently yield heterogeneous populations of neurons and glia that require extended timelines to achieve electrophysiological maturity. More recently, transcription factor-based induction protocols have been show to rapidly generate defined neuronal populations from hiPSCs. NEW METHOD In a manner similar to our previous adaption of NGN2-glutamatergic neuronal induction from hiPSC-derived neural progenitor cells (NPCs), we now adapt an established protocol of lentiviral overexpression of ASCL1 and DLX2 to hiPSC-NPCs. RESULTS We demonstrate induction of a robust and highly pure population of functional GABAergic neurons (iGANs). Importantly, we successfully applied this technique to hiPSC-NPCs derived from ten donors across two independent laboratories, finding it to be an efficient and highly reproducible approach to generate induced GABAergic neurons. Our results show that, like hiPSC-iGANs, NPC-iGANs exhibit increased GABAergic marker expression, electrophysiological maturity, and have distinct transcriptional profiles that distinguish them from other cell-types of the brain. Nonetheless, until donor-matched hiPSCs-iGANs and NPC-iGANs are directly compared, we cannot rule out the possibility that subtle differences in patterning or maturity may exist between these populations; one should always control for cell source in all iGAN experiments. CONCLUSIONS This methodology, relying upon an easily cultured starting population of hiPSC-NPCs, makes possible the generation of large-scale defined co-cultures of induced glutamatergic and GABAergic neurons for hiPSC-based disease models and precision drug screening.
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Affiliation(s)
- Natalie Barretto
- Graduate School of Biomedical Science, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hanwen Zhang
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL, USA
| | - Samuel K Powell
- Graduate School of Biomedical Science, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Michael B Fernando
- Graduate School of Biomedical Science, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Siwei Zhang
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL, USA
| | - Erin K Flaherty
- Graduate School of Biomedical Science, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Seok-Man Ho
- Graduate School of Biomedical Science, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Paul A Slesinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jubao Duan
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL, USA.
| | - Kristen J Brennand
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Pamela Sklar Division of Psychiatric Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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14
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Guo T, Liu G, Du H, Wen Y, Wei S, Li Z, Tao G, Shang Z, Song X, Zhang Z, Xu Z, You Y, Chen B, Rubenstein JL, Yang Z. Dlx1/2 are Central and Essential Components in the Transcriptional Code for Generating Olfactory Bulb Interneurons. Cereb Cortex 2019; 29:4831-4849. [PMID: 30796806 PMCID: PMC6917526 DOI: 10.1093/cercor/bhz018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 01/03/2019] [Accepted: 01/26/2019] [Indexed: 12/22/2022] Open
Abstract
Generation of olfactory bulb (OB) interneurons requires neural stem/progenitor cell specification, proliferation, differentiation, and young interneuron migration and maturation. Here, we show that the homeobox transcription factors Dlx1/2 are central and essential components in the transcriptional code for generating OB interneurons. In Dlx1/2 constitutive null mutants, the differentiation of GSX2+ and ASCL1+ neural stem/progenitor cells in the dorsal lateral ganglionic eminence is blocked, resulting in a failure of OB interneuron generation. In Dlx1/2 conditional mutants (hGFAP-Cre; Dlx1/2F/- mice), GSX2+ and ASCL1+ neural stem/progenitor cells in the postnatal subventricular zone also fail to differentiate into OB interneurons. In contrast, overexpression of Dlx1&2 in embryonic mouse cortex led to ectopic production of OB-like interneurons that expressed Gad1, Sp8, Sp9, Arx, Pbx3, Etv1, Tshz1, and Prokr2. Pax6 mutants generate cortical ectopia with OB-like interneurons, but do not do so in compound Pax6; Dlx1/2 mutants. We propose that DLX1/2 promote OB interneuron development mainly through activating the expression of Sp8/9, which further promote Tshz1 and Prokr2 expression. Based on this study, in combination with earlier ones, we propose a transcriptional network for the process of OB interneuron development.
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Affiliation(s)
- Teng Guo
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Guoping Liu
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Heng Du
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Yan Wen
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Song Wei
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Zhenmeiyu Li
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Guangxu Tao
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Zicong Shang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Xiaolei Song
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Zhuangzhi Zhang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Zhejun Xu
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Yan You
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
| | - Bin Chen
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - John L Rubenstein
- Department of Psychiatry, Nina Ireland Laboratory of Developmental Neurobiology, UCSF Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA
| | - Zhengang Yang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China
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15
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Muley VY, López-Victorio CJ, Ayala-Sumuano JT, González-Gallardo A, González-Santos L, Lozano-Flores C, Wray G, Hernández-Rosales M, Varela-Echavarría A. Conserved and divergent expression dynamics during early patterning of the telencephalon in mouse and chick embryos. Prog Neurobiol 2019; 186:101735. [PMID: 31846713 DOI: 10.1016/j.pneurobio.2019.101735] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 12/08/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022]
Abstract
The mammalian and the avian telencephalon are nearly indistinguishable at early embryonic vesicle stages but differ substantially in form and function at their adult stage. We sequenced and analyzed RNA populations present in mouse and chick during the early stages of embryonic telencephalon to understand conserved and lineage-specific developmental differences. We found approximately 3000 genes that orchestrate telencephalon development. Many chromatin-associated epigenetic and transcription regulators show high expression in both species and some show species-specific expression dynamics. Interestingly, previous studies associated them to autism, intellectual disabilities, and mental retardation supporting a causal link between their impaired functions during telencephalon development and brain dysfunction. Strikingly, the conserved up-regulated genes were differentially enriched in ontologies related to development or functions of the adult brain. Moreover, a differential enrichment of distinct repertoires of transcription factor binding motifs in their upstream promoter regions suggest a species-specific regulation of the various gene groups identified. Overall, our results reveal that the ontogenetic divergences between the mouse and chick telencephalon result from subtle differences in the regulation of common patterning signaling cascades and regulatory networks unique to each species at their very early stages of development.
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Affiliation(s)
| | | | | | | | | | - Carlos Lozano-Flores
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico
| | - Gregory Wray
- Department of Biology, Duke University, Durham, NC, USA
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16
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Pereira M, Birtele M, Rylander Ottosson D. Direct reprogramming into interneurons: potential for brain repair. Cell Mol Life Sci 2019; 76:3953-3967. [PMID: 31250034 PMCID: PMC6785593 DOI: 10.1007/s00018-019-03193-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/29/2022]
Abstract
The brain tissue has only a limited capacity for generating new neurons. Therefore, to treat neurological diseases, there is a need of other cell sources for brain repair. Different sources of cells have been subject of intense research over the years, including cells from primary tissue, stem cell-derived cells and reprogrammed cells. As an alternative, direct reprogramming of resident brain cells into neurons is a recent approach that could provide an attractive method for treating brain injuries or diseases as it uses the patient's own cells for generating novel neurons inside the brain. In vivo reprogramming is still in its early stages but holds great promise as an option for cell therapy. To date, both inhibitory and excitatory neurons have been obtained via in vivo reprogramming, but the precise phenotype or functionality of these cells has not been analysed in detail in most of the studies. Recent data shows that in vivo reprogrammed neurons are able to functionally mature and integrate into the existing brain circuitry, and compose interneuron phenotypes that seem to correlate to their endogenous counterparts. Interneurons are of particular importance as they are essential in physiological brain function and when disturbed lead to several neurological disorders. In this review, we describe a comprehensive overview of the existing studies involving brain repair, including in vivo reprogramming, with a focus on interneurons, along with an overview on current efforts to generate interneurons for cell therapy for a number of neurological diseases.
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Affiliation(s)
- Maria Pereira
- Department of Experimental Medical Science and Lund Stem Cell Center BMC, Lund University, 22141, Lund, Sweden
| | - Marcella Birtele
- Department of Experimental Medical Science and Lund Stem Cell Center BMC, Lund University, 22141, Lund, Sweden
| | - Daniella Rylander Ottosson
- Department of Experimental Medical Science and Lund Stem Cell Center BMC, Lund University, 22141, Lund, Sweden.
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17
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Fritsche E, Barenys M, Klose J, Masjosthusmann S, Nimtz L, Schmuck M, Wuttke S, Tigges J. Development of the Concept for Stem Cell-Based Developmental Neurotoxicity Evaluation. Toxicol Sci 2019; 165:14-20. [PMID: 29982725 DOI: 10.1093/toxsci/kfy175] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human brain development consists of a series of complex spatiotemporal processes that if disturbed by chemical exposure causes irreversible impairments of the nervous system. To evaluate a chemical disturbance in an alternative assay, the concept evolved that the complex procedure of brain development can be disassembled into several neurodevelopmental endpoints which can be represented by a combination of different alternative assays. In this review article, we provide a scientific rationale for the neurodevelopmental endpoints that are currently chosen to establish assays with human stem/and progenitor cells. Assays covering these major neurodevelopmental endpoints are thought to assemble as building blocks of a DNT testing battery.
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Affiliation(s)
- Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany.,Heinrich Heine University, 40225 Düsseldorf, Germany
| | | | - Jördis Klose
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Laura Nimtz
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Martin Schmuck
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Saskia Wuttke
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Julia Tigges
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
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18
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Alzu'bi A, Clowry GJ. Expression of ventral telencephalon transcription factors ASCL1 and DLX2 in the early fetal human cerebral cortex. J Anat 2019; 235:555-568. [PMID: 30861584 PMCID: PMC6704271 DOI: 10.1111/joa.12971] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2019] [Indexed: 01/21/2023] Open
Abstract
In rodent ventral telencephalon, diffusible morphogens induce expression of the proneural transcription factor ASCL1, which in turn induces expression of the transcription factor DLX2 that controls differentiation of cortical interneuron precursors and their tangential migration to the cerebral cortex. RNAseq analysis of human fetal samples of dorsal telencephalon revealed consistently high cortical expression of ASCL1 and increasing expression of DLX2 between 7.5 and 17 post-conceptional weeks (PCW). We explored whether cortical expression of these genes represented a population of intracortically derived interneuron precursors. Immunohistochemistry revealed an ASCL1+ /DLX2+ population of progenitor cells in the human ganglionic eminences between 6.5 and 12 PCW, but in the cortex there also existed a population of ASCL1+ /DLX2- progenitors in the subventricular zone (SVZ) that largely co-expressed cortical markers PAX6 or TBR2, although a few ASCL1+ /PAX6- progenitors were observed in the ventricular zone (VZ) and ASCL1+ cells expressing the interneuron marker GAD67 were present in the SVZ. Although rare in the VZ, DLX2+ cells progressively increased in number between 8 and 12 PCW across the cortical wall and the majority co-expressed LHX6 and originated either in the MGE, migrating to the lateral cortex, or from the septum, populating the medial wall. A minority co-expressed COUP-TFII, which identifies cells from the caudal ganglionic eminence (CGE). By 19 PCW, a significant increase in expression of DLX2 and ASCL1 was observed in the cortical VZ with a small proportion expressing both proteins. The DLX2+ cells did not co-express a cell division marker, so were not progenitors. The majority of DLX2+ cells throughout the cortical plate expressed COUP-TFII rather than LHX6+ . As the VZ declined as a proliferative zone it appeared to be re-defined as a migration pathway for COUP-TFII+ /DLX2+ interneurons from CGE to cortex. Therefore, in developing human cortex, ASCL1 expression predominantly marks a population of intermediate progenitors giving rise to glutamatergic neurons. DLX2 expression predominantly defines post-mitotic interneuron precursors.
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Affiliation(s)
- Ayman Alzu'bi
- The institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- The Institute of Genetic MedicineNewcastle UniversityNewcastle upon TyneUK
- The Department of Basic Medical SciencesYarmouk UniversityIrbidJordan
| | - Gavin J. Clowry
- The institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
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19
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Colasante G, Rubio A, Massimino L, Broccoli V. Direct Neuronal Reprogramming Reveals Unknown Functions for Known Transcription Factors. Front Neurosci 2019; 13:283. [PMID: 30971887 PMCID: PMC6445133 DOI: 10.3389/fnins.2019.00283] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/11/2019] [Indexed: 12/25/2022] Open
Abstract
In recent years, the need to derive sources of specialized cell types to be employed for cell replacement therapies and modeling studies has triggered a fast acceleration of novel cell reprogramming methods. In particular, in neuroscience, a number of protocols for the efficient differentiation of somatic or pluripotent stem cells have been established to obtain a renewable source of different neuronal cell types. Alternatively, several neuronal populations have been generated through direct reprogramming/transdifferentiation, which concerns the conversion of fully differentiated somatic cells into induced neurons. This is achieved through the forced expression of selected transcription factors (TFs) in the donor cell population. The reprogramming cocktail is chosen after an accurate screening process involving lists of TFs enriched into desired cell lineages. In some instances, this type of studies has revealed the crucial role of TFs whose function in the differentiation of a given specific cell type had been neglected or underestimated. Herein, we will speculate on how the in vitro studies have served to better understand physiological mechanisms of neuronal development in vivo.
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Affiliation(s)
- Gaia Colasante
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Alicia Rubio
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,CNR Institute of Neuroscience, Milan, Italy
| | - Luca Massimino
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Vania Broccoli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,CNR Institute of Neuroscience, Milan, Italy
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20
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Carmona-Alcocer V, Rohr KE, Joye DAM, Evans JA. Circuit development in the master clock network of mammals. Eur J Neurosci 2018; 51:82-108. [PMID: 30402923 DOI: 10.1111/ejn.14259] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/08/2018] [Accepted: 10/31/2018] [Indexed: 12/24/2022]
Abstract
Daily rhythms are generated by the circadian timekeeping system, which is orchestrated by the master circadian clock in the suprachiasmatic nucleus (SCN) of mammals. Circadian timekeeping is endogenous and does not require exposure to external cues during development. Nevertheless, the circadian system is not fully formed at birth in many mammalian species and it is important to understand how SCN development can affect the function of the circadian system in adulthood. The purpose of the current review is to discuss the ontogeny of cellular and circuit function in the SCN, with a focus on work performed in model rodent species (i.e., mouse, rat, and hamster). Particular emphasis is placed on the spatial and temporal patterns of SCN development that may contribute to the function of the master clock during adulthood. Additional work aimed at decoding the mechanisms that guide circadian development is expected to provide a solid foundation upon which to better understand the sources and factors contributing to aberrant maturation of clock function.
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Affiliation(s)
| | - Kayla E Rohr
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - Deborah A M Joye
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - Jennifer A Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
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21
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Fan LZ, Nehme R, Adam Y, Jung ES, Wu H, Eggan K, Arnold DB, Cohen AE. All-optical synaptic electrophysiology probes mechanism of ketamine-induced disinhibition. Nat Methods 2018; 15:823-831. [PMID: 30275587 PMCID: PMC6204345 DOI: 10.1038/s41592-018-0142-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 07/15/2018] [Indexed: 02/02/2023]
Abstract
Optical assays of synaptic strength could facilitate studies of neuronal transmission and its dysregulation in disease. Here we introduce a genetic toolbox for all-optical interrogation of synaptic electrophysiology (synOptopatch) via mutually exclusive expression of a channelrhodopsin actuator and an archaerhodopsin-derived voltage indicator. Optically induced activity in the channelrhodopsin-expressing neurons generated excitatory and inhibitory postsynaptic potentials that we optically resolved in reporter-expressing neurons. We further developed a yellow spine-targeted Ca2+ indicator to localize optogenetically triggered synaptic inputs. We demonstrated synOptopatch recordings in cultured rodent neurons and in acute rodent brain slice. In synOptopatch measurements of primary rodent cultures, acute ketamine administration suppressed disynaptic inhibitory feedbacks, mimicking the effect of this drug on network function in both rodents and humans. We localized this action of ketamine to excitatory synapses onto interneurons. These results establish an in vitro all-optical model of disynaptic disinhibition, a synaptic defect hypothesized in schizophrenia-associated psychosis.
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Affiliation(s)
- Linlin Z Fan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Ralda Nehme
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, The Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Yoav Adam
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Eun Sun Jung
- Department of Biology, Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Hao Wu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Kevin Eggan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, The Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Don B Arnold
- Department of Biology, Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Adam E Cohen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
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22
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Chouchane M, Costa MR. Instructing neuronal identity during CNS development and astroglial-lineage reprogramming: Roles of NEUROG2 and ASCL1. Brain Res 2018; 1705:66-74. [PMID: 29510143 DOI: 10.1016/j.brainres.2018.02.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 01/02/2023]
Abstract
The adult mammalian brain contains an enormous variety of neuronal types, which are generally categorized in large groups, based on their neurochemical identity, hodological properties and molecular markers. This broad classification has allowed the correlation between individual neural progenitor populations and their neuronal progeny, thus contributing to probe the cellular and molecular mechanisms involved in neuronal identity determination during central nervous system (CNS) development. In this review, we discuss the contribution of the proneural genes Neurogenin2 (Neurog2) and Achaete-scute homolog 1 (Ascl1) for the specification of neuronal phenotypes in the developing neocortex, cerebellum and retina. Then, we revise recent data on astroglia cell lineage reprogramming into induced neurons using the same proneural proteins to compare the neuronal phenotypes obtained from astroglial cells originated in those CNS regions. We conclude that Ascl1 and Neurog2 have different contributions to determine neuronal fates, depending on the neural progenitor or astroglial population expressing those proneural factors. Finally, we discuss some possible explanations for these seemingly conflicting effects of Ascl1 and Neurog2 and propose future approaches to further dissect the molecular mechanisms of neuronal identity specification.
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Affiliation(s)
- Malek Chouchane
- Brain Institute, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil; Neurological Surgery Department, University of California, San Francisco 94158, USA
| | - Marcos R Costa
- Brain Institute, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil.
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Yang Y, Shen W, Ni Y, Su Y, Yang Z, Zhao C. Impaired Interneuron Development after Foxg1 Disruption. Cereb Cortex 2018; 27:793-808. [PMID: 26620267 DOI: 10.1093/cercor/bhv297] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Interneurons play pivotal roles in the modulation of cortical function; however, the mechanisms that control interneuron development remain unclear. This study aimed to explore a new role for Foxg1 in interneuron development. By crossing Foxg1fl/fl mice with a Dlx5/6-Cre line, we determined that conditional disruption of Foxg1 in the subpallium results in defects in interneuron development. In developing interneurons, the expression levels of several receptors, including roundabout-1, Eph receptor A4, and C-X-C motif receptor 4/7, were strongly downregulated, which led to migration defects after Foxg1 ablation. The transcription factors Dlx1/2 and Mash1, which have been reported to be involved in interneuron development, were significantly upregulated at the mRNA levels. Foxg1 mutant cells developed shorter neurites and fewer branches and displayed severe migration defects in vitro. Notably, Prox1, which is a transcription factor that functions as a key regulator in the development of excitatory neurons, was also dramatically upregulated at both the mRNA and protein levels, suggesting that Prox1 is also important for interneuron development. Our work demonstrates that Foxg1 may act as a critical upstream regulator of Dlx1/2, Mash1, and Prox1 to control interneuron development. These findings will further our understanding of the molecular mechanisms of interneuron development.
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Affiliation(s)
- Ying Yang
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Anatomy and Neuroscience, School of Medicine, Southeast University, Nanjing 210009, China
| | - Wei Shen
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Anatomy and Neuroscience, School of Medicine, Southeast University, Nanjing 210009, China
| | - Yang Ni
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Anatomy and Neuroscience, School of Medicine, Southeast University, Nanjing 210009, China
| | - Yan Su
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Anatomy and Neuroscience, School of Medicine, Southeast University, Nanjing 210009, China
| | - Zhengang Yang
- Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Anatomy and Neuroscience, School of Medicine, Southeast University, Nanjing 210009, China.,Center of Depression, Beijing Institute for Brain Disorders, Beijing 100069, China
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Adnani L, Han S, Li S, Mattar P, Schuurmans C. Mechanisms of Cortical Differentiation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 336:223-320. [DOI: 10.1016/bs.ircmb.2017.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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25
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Solek CM, Feng S, Perin S, Weinschutz Mendes H, Ekker M. Lineage tracing of dlx1a/2a and dlx5a/6a expressing cells in the developing zebrafish brain. Dev Biol 2017; 427:131-147. [PMID: 28479339 DOI: 10.1016/j.ydbio.2017.04.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 04/28/2017] [Accepted: 04/29/2017] [Indexed: 02/06/2023]
Abstract
Lineage tracing of specific populations of progenitor cells provides crucial information about developmental programs. Four members of the Dlx homeobox gene family, Dlx1,2, 5 and 6, are involved in the specification of γ-aminobutyric acid (GABA)ergic neurons in the vertebrate forebrain. Orthologous genes in mammals and teleost show similarities in expression patterns and transcriptional regulation mechanisms. We have used lineage tracing to permanently label dlx-expressing cells in the zebrafish and have characterized the progeny of these cells in the larva and in the juvenile and adult brain. We have found that dlx1a/2a and dlx5a/6a expressing progenitors give rise, for the most part, to small populations of cells which constitute only a small proportion of GABAergic cells in the adult brain tissue. Moreover, some of the cells do not acquire a neuronal phenotype suggesting that, regardless of the time a cell expresses dlx genes in the brain, it can potentially give rise to cells other than neurons. In some instances, labeling larval dlx5a/6a-expressing cells, but not dlx1a/2a-expressing cells, results in massively expanding, widespread clonal expansion throughout the adult brain. Our data provide a detailed lineage analysis of the dlx1a/2a and dlx5a/6a expressing progenitors in the zebrafish brain and lays the foundation for further characterization of the role of these transcription factors beyond the specification of GABAergic neurons.
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Affiliation(s)
- Cynthia M Solek
- CAREG, Department of Biology, University of Ottawa, 20 Marie-Curie Private, Ottawa, ON, Canada K1N 6N5; Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, Canada H3A 2B4
| | - Shengrui Feng
- CAREG, Department of Biology, University of Ottawa, 20 Marie-Curie Private, Ottawa, ON, Canada K1N 6N5; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON, Canada M5G 2M9
| | - Sofia Perin
- CAREG, Department of Biology, University of Ottawa, 20 Marie-Curie Private, Ottawa, ON, Canada K1N 6N5
| | - Hellen Weinschutz Mendes
- CAREG, Department of Biology, University of Ottawa, 20 Marie-Curie Private, Ottawa, ON, Canada K1N 6N5
| | - Marc Ekker
- CAREG, Department of Biology, University of Ottawa, 20 Marie-Curie Private, Ottawa, ON, Canada K1N 6N5.
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Ascl1 promotes tangential migration and confines migratory routes by induction of Ephb2 in the telencephalon. Sci Rep 2017; 7:42895. [PMID: 28276447 PMCID: PMC5343589 DOI: 10.1038/srep42895] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/18/2017] [Indexed: 01/13/2023] Open
Abstract
During development, cortical interneurons generated from the ventral telencephalon migrate tangentially into the dorsal telencephalon. Although Achaete-scute family bHLH transcription factor 1 (Ascl1) plays important roles in the developing telencephalon, whether Ascl1 regulates tangential migration remains unclear. Here, we found that Ascl1 promoted tangential migration along the ventricular zone/subventricular zone (VZ/SVZ) and intermediate zone (IZ) of the dorsal telencephalon. Distal-less homeobox 2 (Dlx2) acted downstream of Ascl1 in promoting tangential migration along the VZ/SVZ but not IZ. We further identified Eph receptor B2 (Ephb2) as a direct target of Ascl1. Knockdown of EphB2 disrupted the separation of the VZ/SVZ and IZ migratory routes. Ephrin-A5, a ligand of EphB2, was sufficient to repel both Ascl1-expressing cells in vitro and tangentially migrating cortical interneurons in vivo. Together, our results demonstrate that Ascl1 induces expression of Dlx2 and Ephb2 to maintain distinct tangential migratory routes in the dorsal telencephalon.
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27
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Lee B, Yoon J, Tri Lam D, Yoon J, Baek K, Jeong Y. Identification of a conserved cis-regulatory element controlling mid-diencephalic expression of mouse Six3. Genesis 2017; 55. [PMID: 28093895 DOI: 10.1002/dvg.23017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 12/15/2016] [Accepted: 01/11/2017] [Indexed: 11/08/2022]
Abstract
The sine oculis homeobox protein Six3 plays pivotal roles in the development of the brain and craniofacial structures. In humans, SIX3 haploinsufficiency results in holoprosencephaly, a defect in anterior midline formation. Although much is known about the evolutionarily conserved functions of Six3, the regulatory mechanism responsible for the expression pattern of Six3 remains relatively unexplored. To understand how the transcription of Six3 is controlled during embryogenesis, we screened ∼300 kb of genomic DNA encompassing the Six3 locus for cis-acting regulatory elements capable of directing reporter gene expression to sites of Six3 transcription in transgenic mouse embryos. We identified a novel enhancer element, whose activity recapitulates endogenous Six3 expression in the ventral midbrain, pretectum, and thalamus. Cross-species comparisons revealed that this Six3 brain enhancer is functionally conserved in other vertebrates. We also showed that normal Six3 transcription in the ventral midbrain and pretectum is dependent on Ascl1, a basic helix-loop-helix proneural factor. Moreover, loss of Ascl1 resulted in downregulation of the Six3 brain enhancer activity, emphasizing its unique role in regulating Six3 expression in the developing brain.
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Affiliation(s)
- Bumwhee Lee
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, 446-701, Republic of Korea
| | - Jiyeon Yoon
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, 446-701, Republic of Korea
| | - Duc Tri Lam
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, 446-701, Republic of Korea
| | - Jaeseung Yoon
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, 446-701, Republic of Korea
| | - Kwanghee Baek
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, 446-701, Republic of Korea
| | - Yongsu Jeong
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, 446-701, Republic of Korea
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Fazel Darbandi S, Poitras L, Monis S, Lindtner S, Yu M, Hatch G, Rubenstein JL, Ekker M. Functional consequences of I56ii Dlx enhancer deletion in the developing mouse forebrain. Dev Biol 2016; 420:S0012-1606(16)30263-9. [PMID: 27983964 DOI: 10.1016/j.ydbio.2016.10.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 09/22/2016] [Accepted: 10/24/2016] [Indexed: 12/12/2022]
Abstract
Dlx homeobox genes encode a group of transcription factors that play an essential role during developmental processes including maintaining the differentiation, proliferation and migration of GABAergic interneurons. The Dlx1/2 and Dlx5/6 genes are expressed in the forebrain and are arranged in convergently transcribed bigene clusters, with I12a/I12b and I56i/I56ii cis-regulatory elements (CREs) located in the intergenic region of each cluster respectively. We have characterized the phenotypic consequences of deleting I56ii on forebrain development and spatial patterning of corridor cells that are involved in guiding thalamocortical projections. Here we report that deletion of I56ii impairs expression of Dlx genes and that of potential targets including Gad2 as well as striatal markers Islet1, Meis2, and Ebf1. In addition, I56ii deletion reduces both the binding of DLX2 in the Dlx5/Dlx6 intergenic region and the presence of H3K9Ac at the Dlx5/Dlx6 locus, consistent with the reduced expression of these genes. Deletion of I56ii reduces the expression of the ISLET1 and CTIP2 in the striatum and disrupts the number of parvalbumin and calretinin expressing cells in the adult somatosensory cortex of the ΔI56ii mice. These data suggest an important regulatory role for I56ii in the developing forebrain by means of a potential regulatory mechanism which may regulate the expression of Dlx genes, notably Dlx6 as well as the spatial patterning of the ventral telencephalon, including possibly corridor cells.
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Affiliation(s)
- S Fazel Darbandi
- Department of Biology, University of Ottawa, 20 Marie Curie, Ottawa, ON Canada K1N 6N5; Department of Psychiatry, School of Medicine, Rock Hall, University of California, San Francisco (UCSF), San Francisco, CA 94158-2324, USA
| | - L Poitras
- Department of Biology, University of Ottawa, 20 Marie Curie, Ottawa, ON Canada K1N 6N5
| | - S Monis
- Department of Biology, University of Ottawa, 20 Marie Curie, Ottawa, ON Canada K1N 6N5
| | - S Lindtner
- Department of Psychiatry, School of Medicine, Rock Hall, University of California, San Francisco (UCSF), San Francisco, CA 94158-2324, USA
| | - M Yu
- Department of Biology, University of Ottawa, 20 Marie Curie, Ottawa, ON Canada K1N 6N5
| | - G Hatch
- Department of Biology, University of Ottawa, 20 Marie Curie, Ottawa, ON Canada K1N 6N5
| | - J L Rubenstein
- Department of Psychiatry, School of Medicine, Rock Hall, University of California, San Francisco (UCSF), San Francisco, CA 94158-2324, USA
| | - M Ekker
- Department of Biology, University of Ottawa, 20 Marie Curie, Ottawa, ON Canada K1N 6N5.
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29
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Masserdotti G, Gascón S, Götz M. Direct neuronal reprogramming: learning from and for development. Development 2016; 143:2494-510. [DOI: 10.1242/dev.092163] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The key signalling pathways and transcriptional programmes that instruct neuronal diversity during development have largely been identified. In this Review, we discuss how this knowledge has been used to successfully reprogramme various cell types into an amazing array of distinct types of functional neurons. We further discuss the extent to which direct neuronal reprogramming recapitulates embryonic development, and examine the particular barriers to reprogramming that may exist given a cell's unique developmental history. We conclude with a recently proposed model for cell specification called the ‘Cook Islands’ model, and consider whether it is a fitting model for cell specification based on recent results from the direct reprogramming field.
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Affiliation(s)
- Giacomo Masserdotti
- Institute of Stem Cell Research, Helmholtz Center Munich, Ingolstädter Landstrasse 1, Neuherberg/Munich D-85764, Germany
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, Großhadernerstrasse 9, Martinsried 82154, Germany
| | - Sergio Gascón
- Institute of Stem Cell Research, Helmholtz Center Munich, Ingolstädter Landstrasse 1, Neuherberg/Munich D-85764, Germany
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, Großhadernerstrasse 9, Martinsried 82154, Germany
| | - Magdalena Götz
- Institute of Stem Cell Research, Helmholtz Center Munich, Ingolstädter Landstrasse 1, Neuherberg/Munich D-85764, Germany
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, Großhadernerstrasse 9, Martinsried 82154, Germany
- Excellence Cluster of Systems Neurology, Großhadernerstrasse 9, Martinsried 82154, Germany
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30
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31
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Ramos AD, Attenello FJ, Lim DA. Uncovering the roles of long noncoding RNAs in neural development and glioma progression. Neurosci Lett 2015; 625:70-9. [PMID: 26733304 DOI: 10.1016/j.neulet.2015.12.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 12/08/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023]
Abstract
In the past decade, thousands of long noncoding RNAs (lncRNAs) have been identified, and emerging data indicate that lncRNAs can have important biological functions and roles in human diseases including cancer. Many lncRNAs appear to be expressed specifically in the brain, and the roles of lncRNAs in neural stem cells (NSCs) and brain development are now beginning to be discovered. Here we review recent advances in understanding the diversity of lncRNA structure and functions in NSCs and brain development. NSCs in the adult mouse ventricular-subventricular zone (V-SVZ) generate new neurons throughout life, and we discuss how key elements of this adult neurogenic system have facilitated the discovery and functional characterization of known and novel lncRNAs. A review of lncRNAs described in other NSC systems reveals a variety of molecular mechanisms, including binding and recruitment of transcription factors, epigenetic modifiers, and RNA-splicing factors. Finally, we review emerging evidence indicating that specific lncRNAs can be key drivers of glial tumors, and discuss next steps towards an in vivo understanding of lncRNA function in development and disease.
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Affiliation(s)
- Alexander D Ramos
- Department of Neurological Surgery, San Francisco, CA 94121, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA 94121, USA
| | - Frank J Attenello
- Department of Neurological Surgery, San Francisco, CA 94121, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA 94121, USA
| | - Daniel A Lim
- Department of Neurological Surgery, San Francisco, CA 94121, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA 94121, USA; San Francisco Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
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32
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Colasante G, Lignani G, Rubio A, Medrihan L, Yekhlef L, Sessa A, Massimino L, Giannelli SG, Sacchetti S, Caiazzo M, Leo D, Alexopoulou D, Dell'Anno MT, Ciabatti E, Orlando M, Studer M, Dahl A, Gainetdinov RR, Taverna S, Benfenati F, Broccoli V. Rapid Conversion of Fibroblasts into Functional Forebrain GABAergic Interneurons by Direct Genetic Reprogramming. Cell Stem Cell 2015; 17:719-734. [PMID: 26526726 DOI: 10.1016/j.stem.2015.09.002] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 06/21/2015] [Accepted: 09/02/2015] [Indexed: 12/26/2022]
Abstract
Transplantation of GABAergic interneurons (INs) can provide long-term functional benefits in animal models of epilepsy and other neurological disorders. Whereas GABAergic INs can be differentiated from embryonic stem cells, alternative sources of GABAergic INs may be more tractable for disease modeling and transplantation. We identified five factors (Foxg1, Sox2, Ascl1, Dlx5, and Lhx6) that convert mouse fibroblasts into induced GABAergic INs (iGABA-INs) possessing molecular signatures of telencephalic INs. Factor overexpression activates transcriptional networks required for GABAergic fate specification. iGABA-INs display progressively maturing firing patterns comparable to cortical INs, form functional synapses, and release GABA. Importantly, iGABA-INs survive and mature upon being grafted into mouse hippocampus. Optogenetic stimulation demonstrated functional integration of grafted iGABA-INs into host circuitry, triggering inhibition of host granule neuron activity. These five factors also converted human cells into functional GABAergic INs. These properties suggest that iGABA-INs have potential for disease modeling and cell-based therapeutic approaches to neurological disorders.
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Affiliation(s)
- Gaia Colasante
- Division of Neuroscience, Ospedale San Raffaele, 20132 Milan, Italy
| | - Gabriele Lignani
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Alicia Rubio
- Division of Neuroscience, Ospedale San Raffaele, 20132 Milan, Italy
| | - Lucian Medrihan
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Latefa Yekhlef
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy; Neuroimmunology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan 20132, Italy
| | - Alessandro Sessa
- Division of Neuroscience, Ospedale San Raffaele, 20132 Milan, Italy
| | - Luca Massimino
- Division of Neuroscience, Ospedale San Raffaele, 20132 Milan, Italy
| | | | - Silvio Sacchetti
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | | | - Damiana Leo
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Dimitra Alexopoulou
- Deep Sequencing Group, Biotechnology Center TU Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | | | - Ernesto Ciabatti
- Division of Neuroscience, Ospedale San Raffaele, 20132 Milan, Italy
| | - Marta Orlando
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Michele Studer
- University of Nice-Sophia Antipolis, 06108 Nice, France; INSERM, iBV, UMR 1091, 06108 Nice, France
| | - Andreas Dahl
- Deep Sequencing Group, Biotechnology Center TU Dresden, Fetscherstrasse 105, 01307 Dresden, Germany
| | - Raul R Gainetdinov
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy; Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Stefano Taverna
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy; Neuroimmunology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan 20132, Italy
| | - Fabio Benfenati
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Vania Broccoli
- Division of Neuroscience, Ospedale San Raffaele, 20132 Milan, Italy; CNR Institute of Neuroscience, 20129 Milan, Italy.
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Masserdotti G, Gillotin S, Sutor B, Drechsel D, Irmler M, Jørgensen HF, Sass S, Theis FJ, Beckers J, Berninger B, Guillemot F, Götz M. Transcriptional Mechanisms of Proneural Factors and REST in Regulating Neuronal Reprogramming of Astrocytes. Cell Stem Cell 2015; 17:74-88. [PMID: 26119235 PMCID: PMC4509553 DOI: 10.1016/j.stem.2015.05.014] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 03/27/2015] [Accepted: 05/27/2015] [Indexed: 12/15/2022]
Abstract
Direct lineage reprogramming induces dramatic shifts in cellular identity, employing poorly understood mechanisms. Recently, we demonstrated that expression of Neurog2 or Ascl1 in postnatal mouse astrocytes generates glutamatergic or GABAergic neurons. Here, we take advantage of this model to study dynamics of neuronal cell fate acquisition at the transcriptional level. We found that Neurog2 and Ascl1 rapidly elicited distinct neurogenic programs with only a small subset of shared target genes. Within this subset, only NeuroD4 could by itself induce neuronal reprogramming in both mouse and human astrocytes, while co-expression with Insm1 was required for glutamatergic maturation. Cultured astrocytes gradually became refractory to reprogramming, in part by the repressor REST preventing Neurog2 from binding to the NeuroD4 promoter. Notably, in astrocytes refractory to Neurog2 activation, the underlying neurogenic program remained amenable to reprogramming by exogenous NeuroD4. Our findings support a model of temporal hierarchy for cell fate change during neuronal reprogramming. Neurog2 and Ascl1 regulate largely non-overlapping neurogenic targets A subset of genes is required and sufficient to convert astrocytes and fibroblasts Neurog2 and REST compete for binding to the NeuroD4 promoter REST deletion enhances Neurog2-mediated reprogramming in vitro
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Affiliation(s)
- Giacomo Masserdotti
- Physiological Genomics, Biomedical Center, University of Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Centre Munich, 85764 Neuherberg, Germany
| | - Sébastien Gillotin
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London, NW7 1AA, UK; Hutchison/MRC Research Center, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK
| | - Bernd Sutor
- Physiological Genomics, Biomedical Center, University of Munich, 80336 Munich, Germany
| | - Daniela Drechsel
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London, NW7 1AA, UK
| | - Martin Irmler
- Institute of Experimental Genetics, Helmholtz Centre Munich, 85764 Neuherberg, Germany
| | - Helle F Jørgensen
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Steffen Sass
- Institute of Computational Biology, Helmholtz Centre Munich, 85764 Neuherberg, Germany
| | - Fabian J Theis
- Institute of Computational Biology, Helmholtz Centre Munich, 85764 Neuherberg, Germany; Department of Mathematics, Technical University Munich, 85748 Garching, Germany
| | - Johannes Beckers
- Institute of Experimental Genetics, Helmholtz Centre Munich, 85764 Neuherberg, Germany; Center of Life and Food Sciences Weihenstephan, Technical University, 85354 Freising, Germany
| | - Benedikt Berninger
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany; Focus Program Translational Neuroscience, Johannes Gutenberg University, D-55128 Mainz, Germany
| | - François Guillemot
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London, NW7 1AA, UK.
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center, University of Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Centre Munich, 85764 Neuherberg, Germany; Munich Cluster for Systems Neurology "SyNergy," Ludwig Maximilian University of Munich, 80539 Munich, Germany.
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Peyre E, Silva CG, Nguyen L. Crosstalk between intracellular and extracellular signals regulating interneuron production, migration and integration into the cortex. Front Cell Neurosci 2015; 9:129. [PMID: 25926769 PMCID: PMC4396449 DOI: 10.3389/fncel.2015.00129] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/19/2015] [Indexed: 11/29/2022] Open
Abstract
During embryogenesis, cortical interneurons are generated by ventral progenitors located in the ganglionic eminences of the telencephalon. They travel along multiple tangential paths to populate the cortical wall. As they reach this structure they undergo intracortical dispersion to settle in their final destination. At the cellular level, migrating interneurons are highly polarized cells that extend and retract processes using dynamic remodeling of microtubule and actin cytoskeleton. Different levels of molecular regulation contribute to interneuron migration. These include: (1) Extrinsic guidance cues distributed along migratory streams that are sensed and integrated by migrating interneurons; (2) Intrinsic genetic programs driven by specific transcription factors that grant specification and set the timing of migration for different subtypes of interneurons; (3) Adhesion molecules and cytoskeletal elements/regulators that transduce molecular signalings into coherent movement. These levels of molecular regulation must be properly integrated by interneurons to allow their migration in the cortex. The aim of this review is to summarize our current knowledge of the interplay between microenvironmental signals and cell autonomous programs that drive cortical interneuron porduction, tangential migration, and intergration in the developing cerebral cortex.
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Affiliation(s)
- Elise Peyre
- GIGA-Neurosciences, University of Liège Liège, Belgium ; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège Liège, Belgium
| | - Carla G Silva
- GIGA-Neurosciences, University of Liège Liège, Belgium ; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège Liège, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences, University of Liège Liège, Belgium ; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège Liège, Belgium ; Wallon Excellence in Lifesciences and Biotechnology, University of Liège Liège, Belgium
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35
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Song H, Lee B, Pyun D, Guimera J, Son Y, Yoon J, Baek K, Wurst W, Jeong Y. Ascl1 and Helt act combinatorially to specify thalamic neuronal identity by repressing Dlxs activation. Dev Biol 2015; 398:280-91. [DOI: 10.1016/j.ydbio.2014.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 11/25/2022]
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Park DH, Hong SJ, Salinas RD, Liu SJ, Sun SW, Sgualdino J, Testa G, Matzuk MM, Iwamori N, Lim DA. Activation of neuronal gene expression by the JMJD3 demethylase is required for postnatal and adult brain neurogenesis. Cell Rep 2014; 8:1290-9. [PMID: 25176653 DOI: 10.1016/j.celrep.2014.07.060] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 07/25/2014] [Accepted: 07/31/2014] [Indexed: 12/11/2022] Open
Abstract
The epigenetic mechanisms that enable lifelong neurogenesis from neural stem cells (NSCs) in the adult mammalian brain are poorly understood. Here, we show that JMJD3, a histone H3 lysine 27 (H3K27) demethylase, acts as a critical activator of neurogenesis from adult subventricular zone (SVZ) NSCs. JMJD3 is upregulated in neuroblasts, and Jmjd3 deletion targeted to SVZ NSCs in both developing and adult mice impairs neuronal differentiation. JMJD3 regulates neurogenic gene expression via interaction at not only promoter regions but also neurogenic enhancer elements. JMJD3 localizes at neural enhancers genome-wide in embryonic brain, and in SVZ NSCs, JMJD3 regulates the I12b enhancer of Dlx2. In Jmjd3-deleted SVZ cells, I12b remains enriched with H3K27me3 and Dlx2-dependent neurogenesis fails. These findings support a model in which JMJD3 and the poised state of key transcriptional regulatory elements comprise an epigenetic mechanism that enables the activation of neurogenic gene expression in adult NSCs throughout life.
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Affiliation(s)
- Dae Hwi Park
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA; Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Sung Jun Hong
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ryan D Salinas
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Siyuan John Liu
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Shawn W Sun
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA; Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jacopo Sgualdino
- European Institute of Oncology (IEO), IFOM-IEO Campus, Via Adamello 16, 20139 Milan, Italy
| | - Giuseppe Testa
- European Institute of Oncology (IEO), IFOM-IEO Campus, Via Adamello 16, 20139 Milan, Italy
| | - Martin M Matzuk
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX 77030, USA; Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Naoki Iwamori
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX 77030, USA; Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Daniel A Lim
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA; Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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Zagozewski JL, Zhang Q, Pinto VI, Wigle JT, Eisenstat DD. The role of homeobox genes in retinal development and disease. Dev Biol 2014; 393:195-208. [PMID: 25035933 DOI: 10.1016/j.ydbio.2014.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 07/02/2014] [Accepted: 07/08/2014] [Indexed: 11/18/2022]
Abstract
Homeobox genes are an evolutionarily conserved class of transcription factors that are critical for development of many organ systems, including the brain and eye. During retinogenesis, homeodomain-containing transcription factors, which are encoded by homeobox genes, play essential roles in the regionalization and patterning of the optic neuroepithelium, specification of retinal progenitors and differentiation of all seven of the retinal cell classes that derive from a common progenitor. Homeodomain transcription factors control retinal cell fate by regulating the expression of target genes required for retinal progenitor cell fate decisions and for terminal differentiation of specific retinal cell types. The essential role of homeobox genes during retinal development is demonstrated by the number of human eye diseases, including colobomas and anophthalmia, which are attributed to homeobox gene mutations. In the following review, we highlight the role of homeodomain transcription factors during retinogenesis and regulation of their gene targets. Understanding the complexities of vertebrate retina development will enhance our ability to drive differentiation of specific retinal cell types towards novel cell-based replacement therapies for retinal degenerative diseases.
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Affiliation(s)
- Jamie L Zagozewski
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada T6G 2H7
| | - Qi Zhang
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada R3E 0J9
| | - Vanessa I Pinto
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0J9
| | - Jeffrey T Wigle
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0J9; Institute of Cardiovascular Sciences, St. Boniface Hospital Research Institute, Winnipeg, MB, Canada R2H 2A6
| | - David D Eisenstat
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada T6G 2H7; Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0J9; Department of Pediatrics, University of Alberta, Edmonton, AB, Canada T6G 1C9.
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Vose LR, Vinukonda G, Diamond D, Korumilli R, Hu F, Zia MTK, Hevner R, Ballabh P. Prenatal betamethasone does not affect glutamatergic or GABAergic neurogenesis in preterm newborns. Neuroscience 2014; 270:148-57. [PMID: 24735821 DOI: 10.1016/j.neuroscience.2014.04.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/03/2014] [Accepted: 04/04/2014] [Indexed: 10/25/2022]
Abstract
Prenatal glucocorticoids (GCs) are routinely used for pregnant women in preterm labor to prevent respiratory distress syndrome and intraventricular hemorrhage in premature infants. However, the effect of antenatal GCs on neurogenesis in preterm neonates remains elusive. Herein, we hypothesized that prenatal GCs might suppress both glutamatergic and GABAergic neurogenesis in preterm rabbits and that this treatment would induce distinct changes in the expression of transcription factors regulating these developmental events. To test our hypotheses, we treated pregnant rabbits with betamethasone at E27 and E28, delivered the pups at E29 (term=32d), and assessed neurogenesis at birth and postnatal day 3. We quantified radial glia (Sox2(+)) and intermediate progenitor cells (Tbr2(+)) in the dorsal cortical subventricular zone to assess glutamatergic neuronal progenitors, and counted Nkx2.1(+) and Dlx2(+) cells in the ganglionic eminence to evaluate GABAergic neurogenesis. In addition, we assayed transcription factors regulating neurogenesis. We found that prenatal GCs did not affect the densities of radial glia and intermediate progenitors of glutamatergic or GABAergic neurons. The number of GABA(+) interneurons in the ganglionic eminence was similar between the prenatal GC-treated pups compared to untreated controls. Moreover, the mRNA expression of transcription factors, including Pax6, Ngn1/2, Emx1/2, Insm1, Dlx1, Nkx2.1, and Gsh2, were comparable between the two groups. However, there was a transient elevation in Mash1 protein in betamethasone-treated pups relative to controls at birth. These data suggest that prenatal GC treatment does not significantly impact the balance of glutamatergic and GABAergic neurogenesis in premature infants.
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Affiliation(s)
- L R Vose
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States
| | - G Vinukonda
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States
| | - D Diamond
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States
| | - R Korumilli
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States
| | - F Hu
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States
| | - M T K Zia
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States
| | - R Hevner
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States
| | - P Ballabh
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, NY, United States; Department of Cell Biology and Anatomy, New York Medical College-Westchester Medical Center, Valhalla, NY, United States.
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Silbereis JC, Nobuta H, Tsai HH, Heine VM, McKinsey GL, Meijer DH, Howard MA, Petryniak MA, Potter GB, Alberta JA, Baraban SC, Stiles CD, Rubenstein JLR, Rowitch DH. Olig1 function is required to repress dlx1/2 and interneuron production in Mammalian brain. Neuron 2014; 81:574-87. [PMID: 24507192 DOI: 10.1016/j.neuron.2013.11.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2013] [Indexed: 12/21/2022]
Abstract
Abnormal GABAergic interneuron density, and imbalance of excitatory versus inhibitory tone, is thought to result in epilepsy, neurodevelopmental disorders, and psychiatric disease. Recent studies indicate that interneuron cortical density is determined primarily by the size of the precursor pool in the embryonic telencephalon. However, factors essential for regulating interneuron allocation from telencephalic multipotent precursors are poorly understood. Here we report that Olig1 represses production of GABAergic interneurons throughout the mouse brain. Olig1 deletion in mutant mice results in ectopic expression and upregulation of Dlx1/2 genes in the ventral medial ganglionic eminences and adjacent regions of the septum, resulting in an ∼30% increase in adult cortical interneuron numbers. We show that Olig1 directly represses the Dlx1/2 I12b intergenic enhancer and that Dlx1/2 functions genetically downstream of Olig1. These findings establish Olig1 as an essential repressor of Dlx1/2 and interneuron production in developing mammalian brain.
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Affiliation(s)
- John C Silbereis
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Hiroko Nobuta
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Hui-Hsin Tsai
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Vivi M Heine
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Gabriel L McKinsey
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Dimphna H Meijer
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Mackenzie A Howard
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Magda A Petryniak
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Gregory B Potter
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - John A Alberta
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Scott C Baraban
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Charles D Stiles
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - John L R Rubenstein
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David H Rowitch
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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Achim K, Salminen M, Partanen J. Mechanisms regulating GABAergic neuron development. Cell Mol Life Sci 2014; 71:1395-415. [PMID: 24196748 PMCID: PMC11113277 DOI: 10.1007/s00018-013-1501-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 12/17/2022]
Abstract
Neurons using gamma-aminobutyric acid (GABA) as their neurotransmitter are the main inhibitory neurons in the mature central nervous system (CNS) and show great variation in their form and function. GABAergic neurons are produced in all of the main domains of the CNS, where they develop from discrete regions of the neuroepithelium. Here, we review the gene expression and regulatory mechanisms controlling the main steps of GABAergic neuron development: early patterning of the proliferative neuroepithelium, production of postmitotic neural precursors, establishment of their identity and migration. By comparing the molecular regulation of these events across CNS, we broadly identify three regions utilizing distinct molecular toolkits for GABAergic fate determination: telencephalon-anterior diencephalon (DLX2 type), posterior diencephalon-midbrain (GATA2 type) and hindbrain-spinal cord (PTF1A and TAL1 types). Similarities and differences in the molecular regulatory mechanisms reveal the core determinants of a GABAergic neuron as well as provide insights into generation of the vast diversity of these neurons.
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Affiliation(s)
- Kaia Achim
- EMBL Heidelberg, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Marjo Salminen
- Department of Veterinary Biosciences, University of Helsinki, Agnes Sjobergin katu 2, PO Box 66, 00014 Helsinki, Finland
| | - Juha Partanen
- Department of Biosciences, University of Helsinki, Viikinkaari 5, PO Box 56, 00014 Helsinki, Finland
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Imayoshi I, Kageyama R. bHLH Factors in Self-Renewal, Multipotency, and Fate Choice of Neural Progenitor Cells. Neuron 2014; 82:9-23. [DOI: 10.1016/j.neuron.2014.03.018] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2014] [Indexed: 12/18/2022]
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RAS/ERK signaling controls proneural genetic programs in cortical development and gliomagenesis. J Neurosci 2014; 34:2169-90. [PMID: 24501358 DOI: 10.1523/jneurosci.4077-13.2014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neural cell fate specification is well understood in the embryonic cerebral cortex, where the proneural genes Neurog2 and Ascl1 are key cell fate determinants. What is less well understood is how cellular diversity is generated in brain tumors. Gliomas and glioneuronal tumors, which are often localized in the cerebrum, are both characterized by a neoplastic glial component, but glioneuronal tumors also have an intermixed neuronal component. A core abnormality in both tumor groups is overactive RAS/ERK signaling, a pro-proliferative signal whose contributions to cell differentiation in oncogenesis are largely unexplored. We found that RAS/ERK activation levels differ in two distinct human tumors associated with constitutively active BRAF. Pilocytic astrocytomas, which contain abnormal glial cells, have higher ERK activation levels than gangliogliomas, which contain abnormal neuronal and glial cells. Using in vivo gain of function and loss of function in the mouse embryonic neocortex, we found that RAS/ERK signals control a proneural genetic switch, inhibiting Neurog2 expression while inducing Ascl1, a competing lineage determinant. Furthermore, we found that RAS/ERK levels control Ascl1's fate specification properties in murine cortical progenitors--at higher RAS/ERK levels, Ascl1(+) progenitors are biased toward proliferative glial programs, initiating astrocytomas, while at moderate RAS/ERK levels, Ascl1 promotes GABAergic neuronal and less glial differentiation, generating glioneuronal tumors. Mechanistically, Ascl1 is phosphorylated by ERK, and ERK phosphoacceptor sites are necessary for Ascl1's GABAergic neuronal and gliogenic potential. RAS/ERK signaling thus acts as a rheostat to influence neural cell fate selection in both normal cortical development and gliomagenesis, controlling Neurog2-Ascl1 expression and Ascl1 function.
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Abstract
Proneural genes encode evolutionarily conserved basic-helix-loop-helix transcription factors. In Drosophila, proneural genes are required and sufficient to confer a neural identity onto naïve ectodermal cells, inducing delamination and subsequent neuronal differentiation. In vertebrates, proneural genes are expressed in cells that already have a neural identity, but they are still required and sufficient to initiate neurogenesis. In all organisms, proneural genes control neurogenesis by regulating Notch-mediated lateral inhibition and initiating the expression of downstream differentiation genes. The general mode of proneural gene function has thus been elucidated. However, the regulatory mechanisms that spatially and temporally control proneural gene function are only beginning to be deciphered. Understanding how proneural gene function is regulated is essential, as aberrant proneural gene expression has recently been linked to a variety of human diseases-ranging from cancer to neuropsychiatric illnesses and diabetes. Recent insights into proneural gene function in development and disease are highlighted herein.
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Affiliation(s)
- Carol Huang
- Department of Pediatrics, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jennifer A Chan
- Department of Pathology & Laboratory Medicine, Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.
| | - Carol Schuurmans
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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Wilkinson G, Dennis D, Schuurmans C. Proneural genes in neocortical development. Neuroscience 2013; 253:256-73. [PMID: 23999125 DOI: 10.1016/j.neuroscience.2013.08.029] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/16/2013] [Accepted: 08/18/2013] [Indexed: 02/01/2023]
Abstract
Neurons, astrocytes and oligodendrocytes arise from CNS progenitor cells at defined times and locations during development, with transcription factors serving as key determinants of these different neural cell fates. An emerging theme is that the transcription factors that specify CNS cell fates function in a context-dependent manner, regulated by post-translational modifications and epigenetic alterations that partition the genome (and hence target genes) into active or silent domains. Here we profile the critical roles of the proneural genes, which encode basic-helix-loop-helix (bHLH) transcription factors, in specifying neural cell identities in the developing neocortex. In particular, we focus on the proneural genes Neurogenin 1 (Neurog1), Neurog2 and Achaete scute-like 1 (Ascl1), which are each expressed in a distinct fashion in the progenitor cell pools that give rise to all of the neuronal and glial cell types of the mature neocortex. Notably, while the basic functions of these proneural genes have been elucidated, it is becoming increasingly evident that tight regulatory controls dictate when, where and how they function. Current efforts to better understand how proneural gene function is regulated will not only improve our understanding of neocortical development, but are also critical to the future development of regenerative therapies for the treatment of neuronal degeneration or disease.
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Affiliation(s)
- G Wilkinson
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
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45
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Evsyukova I, Plestant C, Anton ES. Integrative mechanisms of oriented neuronal migration in the developing brain. Annu Rev Cell Dev Biol 2013; 29:299-353. [PMID: 23937349 DOI: 10.1146/annurev-cellbio-101512-122400] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The emergence of functional neuronal connectivity in the developing cerebral cortex depends on neuronal migration. This process enables appropriate positioning of neurons and the emergence of neuronal identity so that the correct patterns of functional synaptic connectivity between the right types and numbers of neurons can emerge. Delineating the complexities of neuronal migration is critical to our understanding of normal cerebral cortical formation and neurodevelopmental disorders resulting from neuronal migration defects. For the most part, the integrated cell biological basis of the complex behavior of oriented neuronal migration within the developing mammalian cerebral cortex remains an enigma. This review aims to analyze the integrative mechanisms that enable neurons to sense environmental guidance cues and translate them into oriented patterns of migration toward defined areas of the cerebral cortex. We discuss how signals emanating from different domains of neurons get integrated to control distinct aspects of migratory behavior and how different types of cortical neurons coordinate their migratory activities within the developing cerebral cortex to produce functionally critical laminar organization.
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Affiliation(s)
- Irina Evsyukova
- Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599;
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46
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Debiais-Thibaud M, Metcalfe CJ, Pollack J, Germon I, Ekker M, Depew M, Laurenti P, Borday-Birraux V, Casane D. Heterogeneous conservation of Dlx paralog co-expression in jawed vertebrates. PLoS One 2013; 8:e68182. [PMID: 23840829 PMCID: PMC3695995 DOI: 10.1371/journal.pone.0068182] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/27/2013] [Indexed: 01/10/2023] Open
Abstract
Background The Dlx gene family encodes transcription factors involved in the development of a wide variety of morphological innovations that first evolved at the origins of vertebrates or of the jawed vertebrates. This gene family expanded with the two rounds of genome duplications that occurred before jawed vertebrates diversified. It includes at least three bigene pairs sharing conserved regulatory sequences in tetrapods and teleost fish, but has been only partially characterized in chondrichthyans, the third major group of jawed vertebrates. Here we take advantage of developmental and molecular tools applied to the shark Scyliorhinus canicula to fill in the gap and provide an overview of the evolution of the Dlx family in the jawed vertebrates. These results are analyzed in the theoretical framework of the DDC (Duplication-Degeneration-Complementation) model. Results The genomic organisation of the catshark Dlx genes is similar to that previously described for tetrapods. Conserved non-coding elements identified in bony fish were also identified in catshark Dlx clusters and showed regulatory activity in transgenic zebrafish. Gene expression patterns in the catshark showed that there are some expression sites with high conservation of the expressed paralog(s) and other expression sites with events of paralog sub-functionalization during jawed vertebrate diversification, resulting in a wide variety of evolutionary scenarios within this gene family. Conclusion Dlx gene expression patterns in the catshark show that there has been little neo-functionalization in Dlx genes over gnathostome evolution. In most cases, one tandem duplication and two rounds of vertebrate genome duplication have led to at least six Dlx coding sequences with redundant expression patterns followed by some instances of paralog sub-functionalization. Regulatory constraints such as shared enhancers, and functional constraints including gene pleiotropy, may have contributed to the evolutionary inertia leading to high redundancy between gene expression patterns.
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Affiliation(s)
- Mélanie Debiais-Thibaud
- Institut des Sciences de l’Evolution, Université de Montpellier II, UMR5554, Montpellier, France
- * E-mail:
| | - Cushla J. Metcalfe
- Laboratoire Evolution Génome et Spéciation UPR9034 CNRS, Gif-sur-Yvette, France
| | - Jacob Pollack
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Canada
| | - Isabelle Germon
- Laboratoire Evolution Génome et Spéciation UPR9034 CNRS, Gif-sur-Yvette, France
| | - Marc Ekker
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Canada
| | - Michael Depew
- Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, California, United States of America
| | - Patrick Laurenti
- Laboratoire Evolution Génome et Spéciation UPR9034 CNRS, Gif-sur-Yvette, France
- Université Paris Diderot, Paris, France
| | - Véronique Borday-Birraux
- Laboratoire Evolution Génome et Spéciation UPR9034 CNRS, Gif-sur-Yvette, France
- Université Paris Diderot, Paris, France
| | - Didier Casane
- Laboratoire Evolution Génome et Spéciation UPR9034 CNRS, Gif-sur-Yvette, France
- Université Paris Diderot, Paris, France
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47
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MacDonald RB, Pollack JN, Debiais-Thibaud M, Heude E, Talbot JC, Ekker M. The ascl1a and dlx genes have a regulatory role in the development of GABAergic interneurons in the zebrafish diencephalon. Dev Biol 2013; 381:276-85. [PMID: 23747543 DOI: 10.1016/j.ydbio.2013.05.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/08/2013] [Accepted: 05/25/2013] [Indexed: 11/28/2022]
Abstract
During development of the mouse forebrain interneurons, the Dlx genes play a key role in a gene regulatory network (GRN) that leads to the GABAergic phenotype. Here, we have examined the regulatory relationships between the ascl1a, dlx, and gad1b genes in the zebrafish forebrain. Expression of ascl1a overlaps with dlx1a in the telencephalon and diencephalon during early forebrain development. The loss of Ascl1a function results in a loss of dlx expression, and subsequent losses of dlx5a and gad1b expression in the diencephalic prethalamus and hypothalamus. Loss of Dlx1a and Dlx2a function, and, to a lesser extent, of Dlx5a and Dlx6a, impairs gad1b expression in the prethalamus and hypothalamus. We conclude that dlx1a/2a act downstream of ascl1a but upstream of dlx5a/dlx6a and gad1b to activate GABAergic specification. This pathway is conserved in the diencephalon, but has diverged between mammals and teleosts in the telencephalon.
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Affiliation(s)
- Ryan B MacDonald
- Center for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
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Kraus P, Sivakamasundari V, Lim SL, Xing X, Lipovich L, Lufkin T. Making sense of Dlx1 antisense RNA. Dev Biol 2013; 376:224-35. [PMID: 23415800 DOI: 10.1016/j.ydbio.2013.01.035] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 01/27/2013] [Accepted: 01/29/2013] [Indexed: 12/13/2022]
Abstract
Long non-coding RNAs (lncRNAs) have been recently recognized as a major class of regulators in mammalian systems. LncRNAs function by diverse and heterogeneous mechanisms in gene regulation, and are key contributors to development, neurological disorders, and cancer. This emerging importance of lncRNAs, along with recent reports of a functional lncRNA encoded by the mouse Dlx5-Dlx6 locus, led us to interrogate the biological significance of another distal-less antisense lncRNA, the previously uncharacterized Dlx1 antisense (Dlx1as) transcript. We have functionally ablated this antisense RNA via a highly customized gene targeting approach in vivo. Mice devoid of Dlx1as RNA are viable and fertile, and display a mild skeletal and neurological phenotype reminiscent of a Dlx1 gain-of function phenotype, suggesting a role for this non-coding antisense RNA in modulating Dlx1 transcript levels and stability. The reciprocal relationship between Dlx1as and Dlx1 places this sense-antisense pair into a growing class of mammalian lncRNA-mRNA pairs characterized by inverse regulation.
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Affiliation(s)
- Petra Kraus
- Stem Cell and Developmental Biology, Genome Institute of Singapore, Singapore 138672, Singapore
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49
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Kozlova EN, Berens C. Guiding Differentiation of Stem Cells in Vivo by Tetracycline-Controlled Expression of Key Transcription Factors. Cell Transplant 2012; 21:2537-54. [DOI: 10.3727/096368911x637407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transplantation of stem or progenitor cells is an attractive strategy for cell replacement therapy. However, poor long-term survival and insufficiently reproducible differentiation to functionally appropriate cells in vivo still present major obstacles for translation of this methodology to clinical applications. Numerous experimental studies have revealed that the expression of just a few transcription factors can be sufficient to drive stem cell differentiation toward a specific cell type, to transdifferentiate cells from one fate to another, or to dedifferentiate mature cells to pluripotent stem/progenitor cells (iPSCs). We thus propose here to apply the strategy of expressing the relevant key transcription factors to guide the differentiation of transplanted cells to the desired cell fate in vivo. To achieve this requires tools allowing us to control the expression of these genes in the transplant. Here, we describe drug-inducible systems that allow us to sequentially and timely activate gene expression from the outside, with a particular emphasis on the Tet system, which has been widely and successfully used in stem cells. These regulatory systems offer a tool for strictly limiting gene expression to the respective optimal stage after transplantation. This approach will direct the differentiation of the immature stem/progenitor cells in vivo to the desired cell type.
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Affiliation(s)
- Elena N Kozlova
- Department of Neuroscience, Uppsala University, Uppsala, Sweden.
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50
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Nizzardo M, Simone C, Falcone M, Riboldi G, Comi GP, Bresolin N, Corti S. Direct reprogramming of adult somatic cells into other lineages: past evidence and future perspectives. Cell Transplant 2012; 22:921-44. [PMID: 23044010 DOI: 10.3727/096368912x657477] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Direct reprogramming of an adult cell into another differentiated lineage-such as fibroblasts into neurons, cardiomyocytes, or blood cells-without passage through an undifferentiated pluripotent stage is a new area of research that has recently emerged alongside stem cell technology and induced pluripotent stem cell reprogramming; indeed, this avenue of investigation has begun to play a central role in basic biological research and regenerative medicine. Even though the field seems new, its origins go back to the 1980s when it was demonstrated that differentiated adult cells can be converted into another cell lineage through the overexpression of transcription factors, establishing mature cell plasticity. Here, we retrace transdifferentiation experiments from the discovery of master control genes to recent in vivo reprogramming of one somatic cell into another from the perspective of possible applications for the development of new therapeutic approaches for human diseases.
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Affiliation(s)
- Monica Nizzardo
- Department of Neurological Sciences, Dino Ferrari Centre, University of Milan, IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
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