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Eid L, Lokmane L, Raju PK, Tene Tadoum SB, Jiang X, Toulouse K, Lupien-Meilleur A, Charron-Ligez F, Toumi A, Backer S, Lachance M, Lavertu-Jolin M, Montseny M, Lacaille JC, Bloch-Gallego E, Rossignol E. Both GEF domains of the autism and developmental epileptic encephalopathy-associated Trio protein are required for proper tangential migration of GABAergic interneurons. Mol Psychiatry 2025; 30:1338-1358. [PMID: 39300136 PMCID: PMC11919732 DOI: 10.1038/s41380-024-02742-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 08/19/2024] [Accepted: 09/02/2024] [Indexed: 09/22/2024]
Abstract
Recessive and de novo mutations in the TRIO gene are associated with intellectual deficiency (ID), autism spectrum disorder (ASD) and developmental epileptic encephalopathies (DEE). TRIO is a dual guanine nucleotide exchange factor (GEF) that activates Rac1, Cdc42 and RhoA. Trio has been extensively studied in excitatory neurons, and has recently been found to regulate the switch from tangential to radial migration in GABAergic interneurons (INs) through GEFD1-Rac1-dependent SDF1α/CXCR4 signaling. Given the central role of Rho-GTPases during neuronal migration and the implication of IN pathologies in ASD and DEE, we investigated the relative roles of both Trio's GEF domains in regulating the dynamics of INs tangential migration. In Trio-/- mice, we observed reduced numbers of tangentially migrating INs, with intact progenitor proliferation. Further, we noted increased growth cone collapse in developing INs, suggesting altered cytoskeleton dynamics. To bypass the embryonic mortality of Trio-/- mice, we generated Dlx5/6Cre;Trioc/c conditional mutant mice (TriocKO), which develop spontaneous seizures and behavioral deficits reminiscent of ASD and ID. These phenotypes are associated with reduced cortical IN density and functional cortical inhibition. Mechanistically, this reduction of cortical IN numbers reflects a premature switch to radial migration, with an aberrant early entry in the cortical plate, as well as major deficits in cytoskeletal dynamics, including enhanced leading neurite branching and slower nucleokinesis reflecting reduced actin filament condensation and turnover as well as a loss of response to the motogenic effect of EphA4/ephrin A2 reverse signaling. Further, we show that both Trio GEFD1 and GEFD2 domains are required for proper IN migration, with a dominant role of the RhoA-activating GEFD2 domain. Altogether, our data show a critical role of the DEE/ASD-associated Trio gene in the establishment of cortical inhibition and the requirement of both GEF domains in regulating IN migration dynamics.
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Affiliation(s)
- Lara Eid
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Ludmilla Lokmane
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Praveen K Raju
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Samuel Boris Tene Tadoum
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Xiao Jiang
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
| | - Karolanne Toulouse
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Alexis Lupien-Meilleur
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada
| | - François Charron-Ligez
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
| | - Asmaa Toumi
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
| | - Stéphanie Backer
- Institut Cochin- INSERM, U1016-CNRS UMR 8104-Université Paris Cité -24, rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Mathieu Lachance
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
| | - Marisol Lavertu-Jolin
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada
| | - Marie Montseny
- Institut Cochin- INSERM, U1016-CNRS UMR 8104-Université Paris Cité -24, rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Jean-Claude Lacaille
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage, Groupe de recherche sur la signalisation neurale et la circuiterie, Université de Montréal, Montréal, QC, Canada
| | - Evelyne Bloch-Gallego
- Institut Cochin- INSERM, U1016-CNRS UMR 8104-Université Paris Cité -24, rue du Faubourg Saint-Jacques, 75014, Paris, France.
| | - Elsa Rossignol
- Centre de recherche du CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, H3T 1C5, Canada.
- Département de neurosciences, Université de Montréal, Montréal, QC, Canada.
- Département de Pédiatrie, Université de Montréal, Montréal, QC, Canada.
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Assali A, Chenaux G, Cho JY, Berto S, Ehrlich NA, Cowan CW. EphB1 controls long-range cortical axon guidance through a cell non-autonomous role in GABAergic cells. Development 2024; 151:dev201439. [PMID: 38345254 PMCID: PMC10946438 DOI: 10.1242/dev.201439] [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] [Received: 11/15/2022] [Accepted: 01/28/2024] [Indexed: 02/29/2024]
Abstract
EphB1 is required for proper guidance of cortical axon projections during brain development, but how EphB1 regulates this process remains unclear. We show here that EphB1 conditional knockout (cKO) in GABAergic cells (Vgat-Cre), but not in cortical excitatory neurons (Emx1-Cre), reproduced the cortical axon guidance defects observed in global EphB1 KO mice. Interestingly, in EphB1 cKOVgat mice, the misguided axon bundles contained co-mingled striatal GABAergic and somatosensory cortical glutamatergic axons. In wild-type mice, somatosensory axons also co-fasciculated with striatal axons, notably in the globus pallidus, suggesting that a subset of glutamatergic cortical axons normally follows long-range GABAergic axons to reach their targets. Surprisingly, the ectopic axons in EphB1 KO mice were juxtaposed to major blood vessels. However, conditional loss of EphB1 in endothelial cells (Tie2-Cre) did not produce the axon guidance defects, suggesting that EphB1 in GABAergic neurons normally promotes avoidance of these ectopic axons from the developing brain vasculature. Together, our data reveal a new role for EphB1 in GABAergic neurons to influence proper cortical glutamatergic axon guidance during brain development.
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Affiliation(s)
- Ahlem Assali
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - George Chenaux
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas, TX 75390, USA
| | - Jennifer Y. Cho
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Stefano Berto
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Nathan A. Ehrlich
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Christopher W. Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas, TX 75390, USA
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Yildiz CB, Kundu T, Gehrmann J, Koesling J, Ravaei A, Wolff P, Kraft F, Maié T, Jakovcevski M, Pensold D, Zimmermann O, Rossetti G, Costa IG, Zimmer-Bensch G. EphrinA5 regulates cell motility by modulating Snhg15/DNA triplex-dependent targeting of DNMT1 to the Ncam1 promoter. Epigenetics Chromatin 2023; 16:42. [PMID: 37880732 PMCID: PMC10601256 DOI: 10.1186/s13072-023-00516-4] [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] [Received: 05/25/2023] [Accepted: 10/13/2023] [Indexed: 10/27/2023] Open
Abstract
Cell-cell communication is mediated by membrane receptors and their ligands, such as the Eph/ephrin system, orchestrating cell migration during development and in diverse cancer types. Epigenetic mechanisms are key for integrating external "signals", e.g., from neighboring cells, into the transcriptome in health and disease. Previously, we reported ephrinA5 to trigger transcriptional changes of lncRNAs and protein-coding genes in cerebellar granule cells, a cell model for medulloblastoma. LncRNAs represent important adaptors for epigenetic writers through which they regulate gene expression. Here, we investigate a lncRNA-mediated targeting of DNMT1 to specific gene loci by the combined power of in silico modeling of RNA/DNA interactions and wet lab approaches, in the context of the clinically relevant use case of ephrinA5-dependent regulation of cellular motility of cerebellar granule cells. We provide evidence that Snhg15, a cancer-related lncRNA, recruits DNMT1 to the Ncam1 promoter through RNA/DNA triplex structure formation and the interaction with DNMT1. This mediates DNA methylation-dependent silencing of Ncam1, being abolished by ephrinA5 stimulation-triggered reduction of Snhg15 expression. Hence, we here propose a triple helix recognition mechanism, underlying cell motility regulation via lncRNA-targeted DNA methylation in a clinically relevant context.
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Affiliation(s)
- Can Bora Yildiz
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
- Research Training Group 2416 Multi Senses - Multi Scales, RWTH Aachen University, 52074, Aachen, Germany
| | - Tathagata Kundu
- Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Julia Gehrmann
- Institute for Computational Genomics, RWTH Aachen University, Medical Faculty, 52074, Aachen, Germany
| | - Jannis Koesling
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Amin Ravaei
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
- Department of Neurosciences and Rehabilitation, Section of Medical Biochemistry, Molecular Biology and Genetics, University of Ferrara, Ferrara, Italy
| | - Philip Wolff
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Florian Kraft
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Tiago Maié
- Institute for Computational Genomics, RWTH Aachen University, Medical Faculty, 52074, Aachen, Germany
| | - Mira Jakovcevski
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Daniel Pensold
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Olav Zimmermann
- Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Giulia Rossetti
- Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
- Department of Neurology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
- Institute of Neuroscience and Medicine (INM-9)/Institute of Advanced Simulations (IAS-5), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Ivan G Costa
- Institute for Computational Genomics, RWTH Aachen University, Medical Faculty, 52074, Aachen, Germany
| | - Geraldine Zimmer-Bensch
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany.
- Research Training Group 2416 Multi Senses - Multi Scales, RWTH Aachen University, 52074, Aachen, 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: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [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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Li Z, Klein JA, Rampam S, Kurzion R, Campbell NB, Patel Y, Haydar TF, Zeldich E. Asynchronous excitatory neuron development in an isogenic cortical spheroid model of Down syndrome. Front Neurosci 2022; 16:932384. [PMID: 36161168 PMCID: PMC9504873 DOI: 10.3389/fnins.2022.932384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022] Open
Abstract
The intellectual disability (ID) in Down syndrome (DS) is thought to result from a variety of developmental deficits such as alterations in neural progenitor division, neurogenesis, gliogenesis, cortical architecture, and reduced cortical volume. However, the molecular processes underlying these neurodevelopmental changes are still elusive, preventing an understanding of the mechanistic basis of ID in DS. In this study, we used a pair of isogenic (trisomic and euploid) induced pluripotent stem cell (iPSC) lines to generate cortical spheroids (CS) that model the impact of trisomy 21 on brain development. Cortical spheroids contain neurons, astrocytes, and oligodendrocytes and they are widely used to approximate early neurodevelopment. Using single cell RNA sequencing (scRNA-seq), we uncovered cell type-specific transcriptomic changes in the trisomic CS. In particular, we found that excitatory neuron populations were most affected and that a specific population of cells with a transcriptomic profile resembling layer IV cortical neurons displayed the most profound divergence in developmental trajectory between trisomic and euploid genotypes. We also identified candidate genes potentially driving the developmental asynchrony between trisomic and euploid excitatory neurons. Direct comparison between the current isogenic CS scRNA-seq data and previously published datasets revealed several recurring differentially expressed genes between DS and control samples. Altogether, our study highlights the power and importance of cell type-specific analyses within a defined genetic background, coupled with broader examination of mixed samples, to comprehensively evaluate cellular phenotypes in the context of DS.
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Affiliation(s)
- Zhen Li
- Center for Neuroscience Research, Children’s National Hospital, Washington, DC, United States
| | - Jenny A. Klein
- Center for Neuroscience Research, Children’s National Hospital, Washington, DC, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Sanjeev Rampam
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Ronni Kurzion
- Department of Chemistry, Boston University, Boston, MA, United States
| | | | - Yesha Patel
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, United States
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Tarik F. Haydar
- Center for Neuroscience Research, Children’s National Hospital, Washington, DC, United States
| | - Ella Zeldich
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, United States
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Yildiz CB, Zimmer-Bensch G. Role of DNMTs in the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:363-394. [DOI: 10.1007/978-3-031-11454-0_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Reichard J, Zimmer-Bensch G. The Epigenome in Neurodevelopmental Disorders. Front Neurosci 2021; 15:776809. [PMID: 34803599 PMCID: PMC8595945 DOI: 10.3389/fnins.2021.776809] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 12/26/2022] Open
Abstract
Neurodevelopmental diseases (NDDs), such as autism spectrum disorders, epilepsy, and schizophrenia, are characterized by diverse facets of neurological and psychiatric symptoms, differing in etiology, onset and severity. Such symptoms include mental delay, cognitive and language impairments, or restrictions to adaptive and social behavior. Nevertheless, all have in common that critical milestones of brain development are disrupted, leading to functional deficits of the central nervous system and clinical manifestation in child- or adulthood. To approach how the different development-associated neuropathologies can occur and which risk factors or critical processes are involved in provoking higher susceptibility for such diseases, a detailed understanding of the mechanisms underlying proper brain formation is required. NDDs rely on deficits in neuronal identity, proportion or function, whereby a defective development of the cerebral cortex, the seat of higher cognitive functions, is implicated in numerous disorders. Such deficits can be provoked by genetic and environmental factors during corticogenesis. Thereby, epigenetic mechanisms can act as an interface between external stimuli and the genome, since they are known to be responsive to external stimuli also in cortical neurons. In line with that, DNA methylation, histone modifications/variants, ATP-dependent chromatin remodeling, as well as regulatory non-coding RNAs regulate diverse aspects of neuronal development, and alterations in epigenomic marks have been associated with NDDs of varying phenotypes. Here, we provide an overview of essential steps of mammalian corticogenesis, and discuss the role of epigenetic mechanisms assumed to contribute to pathophysiological aspects of NDDs, when being disrupted.
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Affiliation(s)
- Julia Reichard
- Functional Epigenetics in the Animal Model, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Geraldine Zimmer-Bensch
- Functional Epigenetics in the Animal Model, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, Institute for Biology II, RWTH Aachen University, Aachen, Germany
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Pensold D, Gehrmann J, Pitschelatow G, Walberg A, Braunsteffer K, Reichard J, Ravaei A, Linde J, Lampert A, Costa IG, Zimmer-Bensch G. The Expression of the Cancer-Associated lncRNA Snhg15 Is Modulated by EphrinA5-Induced Signaling. Int J Mol Sci 2021; 22:1332. [PMID: 33572758 PMCID: PMC7866228 DOI: 10.3390/ijms22031332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/21/2021] [Accepted: 01/26/2021] [Indexed: 12/16/2022] Open
Abstract
The Eph receptor tyrosine kinases and their respective ephrin-ligands are an important family of membrane receptors, being involved in developmental processes such as proliferation, migration, and in the formation of brain cancer such as glioma. Intracellular signaling pathways, which are activated by Eph receptor signaling, are well characterized. In contrast, it is unknown so far whether ephrins modulate the expression of lncRNAs, which would enable the transduction of environmental stimuli into our genome through a great gene regulatory spectrum. Applying a combination of functional in vitro assays, RNA sequencing, and qPCR analysis, we found that the proliferation and migration promoting stimulation of mouse cerebellar granule cells (CB) with ephrinA5 diminishes the expression of the cancer-related lncRNA Snhg15. In a human medulloblastoma cell line (DAOY) ephrinA5 stimulation similarly reduced SNHG15 expression. Computational analysis identified triple-helix-mediated DNA-binding sites of Snhg15 in promoters of genes found up-regulated upon ephrinA5 stimulation and known to be involved in tumorigenic processes. Our findings propose a crucial role of Snhg15 downstream of ephrinA5-induced signaling in regulating gene transcription in the nucleus. These findings could be potentially relevant for the regulation of tumorigenic processes in the context of glioma.
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Affiliation(s)
- Daniel Pensold
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
| | - Julia Gehrmann
- RWTH Aachen Medical Faculty, Institute for Computational Genomics, 52074 Aachen, Germany; (J.G.); (I.G.C.)
| | - Georg Pitschelatow
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
| | - Asa Walberg
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
| | - Kai Braunsteffer
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
| | - Julia Reichard
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
- Research Training Group 2416 Multi Senses—Multi Scales, RWTH Aachen University, 52074 Aachen, Germany;
| | - Amin Ravaei
- Department of Neurosciences and Rehabilitation, Section of Medical Biochemistry, Molecular Biology and Genetics, University of Ferrara, 44100 Ferrara, Italy;
| | - Jenice Linde
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
- Research Training Group 2416 Multi Senses—Multi Scales, RWTH Aachen University, 52074 Aachen, Germany;
| | - Angelika Lampert
- Research Training Group 2416 Multi Senses—Multi Scales, RWTH Aachen University, 52074 Aachen, Germany;
- RWTH Aachen Medical Faculty, Institute of Physiology, 52074 Aachen, Germany
| | - Ivan G. Costa
- RWTH Aachen Medical Faculty, Institute for Computational Genomics, 52074 Aachen, Germany; (J.G.); (I.G.C.)
| | - Geraldine Zimmer-Bensch
- Division of Functional Epigenetics, Institute of Zoology (Biology 2), RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany; (D.P.); (G.P.); (A.W.); (K.B.); (J.R.); (J.L.)
- Research Training Group 2416 Multi Senses—Multi Scales, RWTH Aachen University, 52074 Aachen, Germany;
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Mencio CP, Hussein RK, Yu P, Geller HM. The Role of Chondroitin Sulfate Proteoglycans in Nervous System Development. J Histochem Cytochem 2021; 69:61-80. [PMID: 32936033 PMCID: PMC7780190 DOI: 10.1369/0022155420959147] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
The orderly development of the nervous system is characterized by phases of cell proliferation and differentiation, neural migration, axonal outgrowth and synapse formation, and stabilization. Each of these processes is a result of the modulation of genetic programs by extracellular cues. In particular, chondroitin sulfate proteoglycans (CSPGs) have been found to be involved in almost every aspect of this well-orchestrated yet delicate process. The evidence of their involvement is complex, often contradictory, and lacking in mechanistic clarity; however, it remains obvious that CSPGs are key cogs in building a functional brain. This review focuses on current knowledge of the role of CSPGs in each of the major stages of neural development with emphasis on areas requiring further investigation.
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Affiliation(s)
- Caitlin P Mencio
- Laboratory of Developmental Neurobiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Rowan K Hussein
- Laboratory of Developmental Neurobiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Panpan Yu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education Joint International Research Laboratory of CNS Regeneration, Jinan University, Guangzhou, China
| | - Herbert M Geller
- Laboratory of Developmental Neurobiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland
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Liu Z, Zhang Z, Lindtner S, Li Z, Xu Z, Wei S, Liang Q, Wen Y, Tao G, You Y, Chen B, Wang Y, Rubenstein JL, Yang Z. Sp9 Regulates Medial Ganglionic Eminence-Derived Cortical Interneuron Development. Cereb Cortex 2020; 29:2653-2667. [PMID: 29878134 DOI: 10.1093/cercor/bhy133] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 05/06/2018] [Indexed: 11/12/2022] Open
Abstract
Immature neurons generated by the subpallial MGE tangentially migrate to the cortex where they become parvalbumin-expressing (PV+) and somatostatin (SST+) interneurons. Here, we show that the Sp9 transcription factor controls the development of MGE-derived cortical interneurons. SP9 is expressed in the MGE subventricular zone and in MGE-derived migrating interneurons. Sp9 null and conditional mutant mice have approximately 50% reduction of MGE-derived cortical interneurons, an ectopic aggregation of MGE-derived neurons in the embryonic ventral telencephalon, and an increased ratio of SST+/PV+ cortical interneurons. RNA-Seq and SP9 ChIP-Seq reveal that SP9 regulates MGE-derived cortical interneuron development through controlling the expression of key transcription factors Arx, Lhx6, Lhx8, Nkx2-1, and Zeb2 involved in interneuron development, as well as genes implicated in regulating interneuron migration Ackr3, Epha3, and St18. Thus, Sp9 has a central transcriptional role in MGE-derived cortical interneuron development.
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Affiliation(s)
- Zhidong Liu
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhuangzhi Zhang
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Susan Lindtner
- Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Zhenmeiyu Li
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhejun Xu
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Song Wei
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qifei Liang
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yan Wen
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guangxu Tao
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yan You
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Bin Chen
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Yanling Wang
- Department of Neurological Sciences, Rush University Medical Center, Rush University, Chicago, IL, USA
| | - John L Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Zhengang Yang
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
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11
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Baudet S, Bécret J, Nicol X. Approaches to Manipulate Ephrin-A:EphA Forward Signaling Pathway. Pharmaceuticals (Basel) 2020; 13:ph13070140. [PMID: 32629797 PMCID: PMC7407804 DOI: 10.3390/ph13070140] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/19/2020] [Accepted: 06/28/2020] [Indexed: 02/07/2023] Open
Abstract
Erythropoietin-producing hepatocellular carcinoma A (EphA) receptors and their ephrin-A ligands are key players of developmental events shaping the mature organism. Their expression is mostly restricted to stem cell niches in adults but is reactivated in pathological conditions including lesions in the heart, lung, or nervous system. They are also often misregulated in tumors. A wide range of molecular tools enabling the manipulation of the ephrin-A:EphA system are available, ranging from small molecules to peptides and genetically-encoded strategies. Their mechanism is either direct, targeting EphA receptors, or indirect through the modification of intracellular downstream pathways. Approaches enabling manipulation of ephrin-A:EphA forward signaling for the dissection of its signaling cascade, the investigation of its physiological roles or the development of therapeutic strategies are summarized here.
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12
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Symmank J, Gölling V, Gerstmann K, Zimmer G. The Transcription Factor LHX1 Regulates the Survival and Directed Migration of POA-derived Cortical Interneurons. Cereb Cortex 2020; 29:1644-1658. [PMID: 29912395 DOI: 10.1093/cercor/bhy063] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 12/17/2022] Open
Abstract
The delicate balance of excitation and inhibition is crucial for proper function of the cerebral cortex, relying on the accurate number and subtype composition of inhibitory gamma-aminobutyric (GABA)-expressing interneurons. Various intrinsic and extrinsic factors precisely orchestrate their multifaceted development including the long-range migration from the basal telencephalon to cortical targets as well as interneuron survival throughout the developmental period. Particularly expressed guidance receptors were described to channel the migration of cortical interneurons deriving from the medial ganglionic eminence (MGE) and the preoptic area (POA) along distinct routes. Hence, unveiling the regulatory genetic networks controlling subtype-specific gene expression profiles is key to understand interneuron-specific developmental programs and to reveal causes for associated disorders. In contrast to MGE-derived interneurons, little is known about the transcriptional networks in interneurons born in the POA. Here, we provide first evidence for the LIM-homeobox transcription factor LHX1 as a crucial key player in the post-mitotic development of POA-derived cortical interneurons. By transcriptional regulation of related genes, LHX1 modulates their survival as well as the subtype-specific expression of guidance receptors of the Eph/ephrin family, thereby affecting directional migration and layer distribution in the adult cortex.
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Affiliation(s)
- Judit Symmank
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Vanessa Gölling
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Katrin Gerstmann
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Geraldine Zimmer
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
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13
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Djankpa FT, Lischka F, Chatterjee M, Juliano SL. KCC2 Manipulation Alters Features of Migrating Interneurons in Ferret Neocortex. Cereb Cortex 2019; 29:5072-5084. [PMID: 30953440 DOI: 10.1093/cercor/bhz048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 12/23/2018] [Indexed: 12/29/2022] Open
Abstract
KCC2 is a brain specific chloride-potassium cotransporter affecting neuronal development including migration and cellular maturation. It modulates chloride homeostasis influencing the switch of GABA from depolarizing to hyperpolarizing, which contributes to the cues that influence the termination of neuronal migration. The expression of KCC2 during migration of interneurons, therefore, correlates with the ability of these cells to respond to GABA as a stop signal. Manipulation of KCC2 in development can affect various aspects of migrating neurons, including the speed. We describe the effect of KCC2 downregulation and inhibition on features of migrating interneurons of normal ferret kits and those treated with methylazoxymethanol acetate, which increases KCC2. Treatment of organotypic cultures with Bisphenol A, an environmental toxin that alters gene expression, also downregulates KCC2 protein. In organotypic slices treated with the KCC2 antagonist VU0240551, chloride imaging shows inhibition of KCC2 via blockade of chloride flux. Time-lapse video imaging of organotypic cultures treated with either drug, shows a significant increase in the average speed, step size, and number of turns made by migrating neurons leaving the ganglionic eminence. Our findings demonstrate the harmful effect of environmental toxins on brain development and potential consequences in the pathogenesis of neurodevelopmental disorders.
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Affiliation(s)
- F T Djankpa
- Program in Neuroscience, Uniformed Services University of the Health Sciences, USUHS, Bethesda, MD 20814-4799, USA
- Center for the Study of Traumatic Stress, Bethesda, MD 20814-4799, USA
| | - F Lischka
- Center for Neuroscience and Regenerative Medicine, USUHS, Bethesda, MD 20814-4799, USA
| | - M Chatterjee
- Center for Neuroscience and Regenerative Medicine, USUHS, Bethesda, MD 20814-4799, USA
| | - S L Juliano
- Program in Neuroscience, Uniformed Services University of the Health Sciences, USUHS, Bethesda, MD 20814-4799, USA
- Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA
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14
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Raja E, Morikawa M, Nishida J, Tanabe R, Takahashi K, Seeherman HJ, Saito N, Todo T, Miyazono K. Tyrosine kinase Eph receptor A6 sensitizes glioma-initiating cells towards bone morphogenetic protein-induced apoptosis. Cancer Sci 2019; 110:3486-3496. [PMID: 31483918 PMCID: PMC6825014 DOI: 10.1111/cas.14187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/22/2019] [Accepted: 08/25/2019] [Indexed: 12/12/2022] Open
Abstract
Bone morphogenetic protein (BMP) signaling plays important roles in glioblastoma multiforme (GBM), a lethal form of brain tumor. BMP reduces GBM tumorigenicity through its differentiation‐ and apoptosis‐inducing effects on glioma‐initiating cells (GIC). However, some GIC do not respond to the tumor suppressive effects of BMP. Using a phosphoreceptor tyrosine kinase array, we found that EPHA6 (erythropoietin‐producing hepatocellular carcinoma receptor A6) phosphorylation was regulated by BMP‐2 signaling in some GIC. Analysis of The Cancer Genome Atlas showed that EPHA6 expression was lower in patients with GBM than in the normal brain, and that high EPHA6 expression was correlated with better prognosis. EPHA6 receptor increased the susceptibility of both sensitive and resistant GIC to BMP‐2‐induced apoptosis. The cooperative effect on apoptosis induction depended on the kinase activity of BMP type I receptor but was independent of EPHA6 kinase function. Overexpression of the EPHA6 receptor in GIC resulted in the formation of a protein complex of EPHA6 receptor and the BMP type I receptor ALK‐2, which was associated with BMP‐induced apoptosis in GIC. Intracranial injection of GIC into nude mice showed that gain‐of‐function of EPHA6 together with BMP‐2 pretreatment slowed GBM tumor progression in the mouse brain and promoted mouse survival. In summary, EPHA6 together with BMP‐2 signaling led to apoptotic cell death in GIC, and thus is a putative tumor suppressor in GBM.
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Affiliation(s)
- Erna Raja
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masato Morikawa
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Jun Nishida
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ryo Tanabe
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kei Takahashi
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | | | - Nobuhito Saito
- Department of Neurosurgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoki Todo
- Division of Innovative Cancer Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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15
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Topographical cues control the morphology and dynamics of migrating cortical interneurons. Biomaterials 2019; 214:119194. [DOI: 10.1016/j.biomaterials.2019.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/04/2019] [Indexed: 12/30/2022]
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16
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Tao G, Li Z, Wen Y, Song X, Wei S, Du H, Yang Z, Xu Z, You Y. Transcription Factors Sp8 and Sp9 Regulate Medial Ganglionic Eminence-Derived Cortical Interneuron Migration. Front Mol Neurosci 2019; 12:75. [PMID: 31001083 PMCID: PMC6454190 DOI: 10.3389/fnmol.2019.00075] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022] Open
Abstract
Cortical interneurons are derived from the subpallium and reach the developing cortex through long tangential migration. Mature cortical interneurons are characterized by remarkable morphological, molecular, and functional diversity. The calcium-binding protein parvalbumin (PV) and neuropeptide somatostatin (SST) identify most medial ganglionic eminence (MGE)-derived cortical interneurons. Previously, we demonstrated that Sp9 plays a curial transcriptional role in regulating MGE-derived cortical interneuron development. Here, we show that SP8 protein is weekly expressed in the MGE mantle zone of wild type mice but upregulated in Sp9 null mutants. PV+ cortical interneurons were severely lost in Sp8/Sp9 double conditional knockouts due to defects in tangential migration compared with Sp9 single mutants, suggesting that Sp8/9 coordinately regulate PV+ cortical interneuron development. We provide evidence that Sp8/Sp9 activity is required for normal MGE-derived cortical interneuron migration, at least in part, through regulating the expression of EphA3, Ppp2r2c, and Rasgef1b.
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Affiliation(s)
- Guangxu Tao
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhenmeiyu Li
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yan Wen
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiaolei Song
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Song Wei
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Heng Du
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhengang Yang
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhejun Xu
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yan You
- State Key Laboratory of Medical Neurobiology, MOE Frontier Research Center for Brain Science, Department of Neurology, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
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17
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Diverse facets of cortical interneuron migration regulation – Implications of neuronal activity and epigenetics. Brain Res 2018; 1700:160-169. [DOI: 10.1016/j.brainres.2018.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/02/2018] [Accepted: 09/03/2018] [Indexed: 01/21/2023]
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18
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García-Peña CM, Ávila-González D, Miquelajáuregui A, Lozano-Flores C, Mastick GS, Tamariz E, Varela-Echavarría A. Neurophilic Descending Migration of Dorsal Midbrain Neurons Into the Hindbrain. Front Neuroanat 2018; 12:96. [PMID: 30483071 PMCID: PMC6243072 DOI: 10.3389/fnana.2018.00096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/22/2018] [Indexed: 12/29/2022] Open
Abstract
Stereotypic cell migrations in the developing brain are fundamental for the proper patterning of brain regions and formation of neural networks. In this work, we uncovered in the developing rat, a population of neurons expressing tyrosine hydroxylase (TH) that migrates posteriorly from the alar plate of the midbrain, in neurophilic interaction with axons of the mesencephalic nucleus of the trigeminal nerve. A fraction of this population was also shown to traverse the mid-hindbrain boundary, reaching the vicinity of the locus coeruleus (LC) in rhombomere 1 (r1). This migratory population, however, does not have a noradrenergic (NA) phenotype and, in keeping with its midbrain origin, expresses Otx2 which is down regulated upon migration into the hindbrain. The interaction with the trigeminal mesencephalic axons is necessary for the arrangement and distribution of migratory cells as these aspects are dramatically altered in whole embryo cultures upon disruption of trigeminal axon projection by interfering with DCC function. Moreover, in mouse embryos in an equivalent developmental stage, we detected a cell population that also migrates caudally within the midbrain apposed to mesencephalic trigeminal axons but that does not express TH; a fraction of this population expresses calbindin instead. Overall, our work identified TH-expressing neurons from the rat midbrain alar plate that migrate tangentially over long distances within the midbrain and into the hindbrain by means of a close interaction with trigeminal mesencephalic axons. A different migratory population in this region and also in mouse embryos revealed diversity among the cells that follow this descending migratory pathway.
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Affiliation(s)
- Claudia M García-Peña
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, México
| | - Daniela Ávila-González
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, México
| | - Amaya Miquelajáuregui
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, México
| | - Carlos Lozano-Flores
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, México
| | - Grant S Mastick
- Department of Biology, University of Nevada, Reno, Reno, NV, United States
| | - Elisa Tamariz
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, México
| | - Alfredo Varela-Echavarría
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, México
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19
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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: 2.1] [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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20
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Franchi SA, Macco R, Astro V, Tonoli D, Savino E, Valtorta F, Sala K, Botta M, de Curtis I. A Method to Culture GABAergic Interneurons Derived from the Medial Ganglionic Eminence. Front Cell Neurosci 2018; 11:423. [PMID: 29358905 PMCID: PMC5766683 DOI: 10.3389/fncel.2017.00423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 12/18/2017] [Indexed: 11/13/2022] Open
Abstract
Understanding the mechanisms guiding interneuron development is a central aspect of the current research on cortical/hippocampal interneurons, which is highly relevant to brain function and pathology. In this methodological study we have addressed the setup of protocols for the reproducible culture of dissociated cells from murine medial ganglionic eminences (MGEs), to provide a culture system for the analysis of interneurons in vitro. This study includes the detailed protocols for the preparation of the dissociated cells, and for their culture on optimal substrates for cell migration or differentiation. These cultures enriched in interneurons may allow the investigation of the migratory behavior of interneuron precursors and their differentiation in vitro, up to the formation of morphologically identifiable GABAergic synapses. Live imaging of MGE-derived cells plated on proper substrates shows that they are useful to study the migratory behavior of the precursors, as well as the behavior of growth cones during the development of neurites. Most MGE-derived precursors develop into polarized GABAergic interneurons as determined by axonal, dendritic, and GABAergic markers. We present also a comparison of cells from WT and mutant mice as a proof of principle for the use of these cultures for the analysis of the migration and differentiation of GABAergic cells with different genetic backgrounds. The culture enriched in interneurons described here represents a useful experimental system to examine in a relatively easy and fast way the morpho-functional properties of these cells under physiological or pathological conditions, providing a powerful tool to complement the studies in vivo.
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Affiliation(s)
- Sira A Franchi
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Romina Macco
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Veronica Astro
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Diletta Tonoli
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Elisa Savino
- Neuropsychopharmacology Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Flavia Valtorta
- Neuropsychopharmacology Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Kristyna Sala
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Martina Botta
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Ivan de Curtis
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
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21
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Ansen-Wilson LJ, Lipinski RJ. Gene-environment interactions in cortical interneuron development and dysfunction: A review of preclinical studies. Neurotoxicology 2017; 58:120-129. [PMID: 27932026 PMCID: PMC5328258 DOI: 10.1016/j.neuro.2016.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 12/03/2016] [Accepted: 12/03/2016] [Indexed: 12/26/2022]
Abstract
Cortical interneurons (cINs) are a diverse group of locally projecting neurons essential to the organization and regulation of neural networks. Though they comprise only ∼20% of neurons in the neocortex, their dynamic modulation of cortical activity is requisite for normal cognition and underlies multiple aspects of learning and memory. While displaying significant morphological, molecular, and electrophysiological variability, cINs collectively function to maintain the excitatory-inhibitory balance in the cortex by dampening hyperexcitability and synchronizing activity of projection neurons, primarily through use of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Disruption of the excitatory-inhibitory balance is a common pathophysiological feature of multiple seizure and neuropsychiatric disorders, including epilepsy, schizophrenia, and autism. While most studies have focused on genetic disruption of cIN development in these conditions, emerging evidence indicates that cIN development is exquisitely sensitive to teratogenic disruption. Here, we review key aspects of cIN development, including specification, migration, and integration into neural circuits. Additionally, we examine the mechanisms by which prenatal exposure to common chemical and environmental agents disrupt these events in preclinical models. Understanding how genetic and environmental factors interact to disrupt cIN development and function has tremendous potential to advance prevention and treatment of prevalent seizure and neuropsychiatric illnesses.
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Affiliation(s)
- Lydia J Ansen-Wilson
- Department of Comparative Biosciences School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI, 53706, USA; Comparative Biomedical Sciences Graduate Program, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI, 53706, USA.
| | - Robert J Lipinski
- Department of Comparative Biosciences School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI, 53706, USA; Comparative Biomedical Sciences Graduate Program, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI, 53706, USA; Molecular and Environmental Toxicology Center, School of Medicine and Public Health, University of Wisconsin-Madison, 1010B McArdle Building, 1400 University Avenue, Madison, WI, 53706, USA.
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22
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Stouffer MA, Golden JA, Francis F. Neuronal migration disorders: Focus on the cytoskeleton and epilepsy. Neurobiol Dis 2015; 92:18-45. [PMID: 26299390 DOI: 10.1016/j.nbd.2015.08.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/05/2015] [Accepted: 08/12/2015] [Indexed: 01/28/2023] Open
Abstract
A wide spectrum of focal, regional, or diffuse structural brain abnormalities, collectively known as malformations of cortical development (MCDs), frequently manifest with intellectual disability (ID), epilepsy, and/or autistic spectrum disorder (ASD). As the acronym suggests, MCDs are perturbations of the normal architecture of the cerebral cortex and hippocampus. The pathogenesis of these disorders remains incompletely understood; however, one area that has provided important insights has been the study of neuronal migration. The amalgamation of human genetics and experimental studies in animal models has led to the recognition that common genetic causes of neurodevelopmental disorders, including many severe epilepsy syndromes, are due to mutations in genes regulating the migration of newly born post-mitotic neurons. Neuronal migration genes often, though not exclusively, code for proteins involved in the function of the cytoskeleton. Other cellular processes, such as cell division and axon/dendrite formation, which similarly depend on cytoskeletal functions, may also be affected. We focus here on how the susceptibility of the highly organized neocortex and hippocampus may be due to their laminar organization, which involves the tight regulation, both temporally and spatially, of gene expression, specialized progenitor cells, the migration of neurons over large distances and a birthdate-specific layering of neurons. Perturbations in neuronal migration result in abnormal lamination, neuronal differentiation defects, abnormal cellular morphology and circuit formation. Ultimately this results in disorganized excitatory and inhibitory activity leading to the symptoms observed in individuals with these disorders.
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Affiliation(s)
- Melissa A Stouffer
- INSERM UMRS 839, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie, Paris, France; Institut du Fer à Moulin, Paris, France
| | - Jeffrey A Golden
- Department of Pathology, Brigham & Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Fiona Francis
- INSERM UMRS 839, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie, Paris, France; Institut du Fer à Moulin, Paris, France.
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Abstract
In the developing telencephalon, the medial ganglionic eminence (MGE) generates many cortical and virtually all striatal interneurons. While the molecular mechanisms controlling the migration of interneurons to the cortex have been extensively studied, very little is known about the nature of the signals that guide interneurons to the striatum. Here we report that the allocation of MGE-derived interneurons in the developing striatum of the mouse relies on a combination of chemoattractive and chemorepulsive activities. Specifically, interneurons migrate toward the striatum in response to Nrg1/ErbB4 chemoattraction, and avoid migrating into the adjacent cortical territories by a repulsive activity mediated by EphB/ephrinB signaling. Our results also suggest that the responsiveness of MGE-derived striatal interneurons to these cues is at least in part controlled by the postmitotic activity of the transcription factor Nkx2-1. This study therefore reveals parallel mechanisms for the migration of MGE-derived interneurons to the striatum and the cerebral cortex.
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Maeda N. Proteoglycans and neuronal migration in the cerebral cortex during development and disease. Front Neurosci 2015; 9:98. [PMID: 25852466 PMCID: PMC4369650 DOI: 10.3389/fnins.2015.00098] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 03/07/2015] [Indexed: 12/13/2022] Open
Abstract
Chondroitin sulfate proteoglycans and heparan sulfate proteoglycans are major constituents of the extracellular matrix and the cell surface in the brain. Proteoglycans bind with many proteins including growth factors, chemokines, axon guidance molecules, and cell adhesion molecules through both the glycosaminoglycan and the core protein portions. The functions of proteoglycans are flexibly regulated due to the structural variability of glycosaminoglycans, which are generated by multiple glycosaminoglycan synthesis and modifying enzymes. Neuronal cell surface proteoglycans such as PTPζ, neuroglycan C and syndecan-3 function as direct receptors for heparin-binding growth factors that induce neuronal migration. The lectican family, secreted chondroitin sulfate proteoglycans, forms large aggregates with hyaluronic acid and tenascins, in which many signaling molecules and enzymes including matrix proteases are preserved. In the developing cerebrum, secreted chondroitin sulfate proteoglycans such as neurocan, versican and phosphacan are richly expressed in the areas that are strategically important for neuronal migration such as the striatum, marginal zone, subplate and subventricular zone in the neocortex. These proteoglycans may anchor various attractive and/or repulsive cues, regulating the migration routes of inhibitory neurons. Recent studies demonstrated that the genes encoding proteoglycan core proteins and glycosaminoglycan synthesis and modifying enzymes are associated with various psychiatric and intellectual disorders, which may be related to the defects of neuronal migration.
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Affiliation(s)
- Nobuaki Maeda
- Neural Network Project, Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science Setagaya, Japan
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25
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Development of cortical interneurons. Neuropsychopharmacology 2015; 40:16-23. [PMID: 25103177 PMCID: PMC4262895 DOI: 10.1038/npp.2014.171] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/16/2014] [Accepted: 06/26/2014] [Indexed: 01/15/2023]
Abstract
Inhibitory local circuit neurons (LCNs), often called interneurons, have vital roles in the development and function of cortical networks. Their inhibitory influences regulate both the excitability of cortical projection neurons on the level of individual cells, and the synchronous activity of projection neuron ensembles that appear to be a neural basis for major aspects of cognitive processing. Dysfunction of LCNs has been associated with neurological and psychiatric diseases, such as epilepsy, schizophrenia, and autism. Here we review progress in understanding LCN fate determination, their nonradial migration to the cortex, their maturation within the cortex, and the contribution of LCN dysfunction to neuropsychiatric disorders.
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Gerstmann K, Pensold D, Symmank J, Khundadze M, Hübner CA, Bolz J, Zimmer G. Thalamic afferents influence cortical progenitors via ephrin A5-EphA4 interactions. Development 2014; 142:140-50. [PMID: 25480914 DOI: 10.1242/dev.104927] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The phenotype of excitatory cerebral cortex neurons is specified at the progenitor level, orchestrated by various intrinsic and extrinsic factors. Here, we provide evidence for a subcortical contribution to cortical progenitor regulation by thalamic axons via ephrin A5-EphA4 interactions. Ephrin A5 is expressed by thalamic axons and represents a high-affinity ligand for EphA4 receptors detected in cortical precursors. Recombinant ephrin A5-Fc protein, as well as ephrin A ligand-expressing, thalamic axons affect the output of cortical progenitor division in vitro. Ephrin A5-deficient mice show an altered division mode of radial glial cells (RGCs) accompanied by increased numbers of intermediate progenitor cells (IPCs) and an elevated neuronal production for the deep cortical layers at E13.5. In turn, at E16.5 the pool of IPCs is diminished, accompanied by reduced rates of generated neurons destined for the upper cortical layers. This correlates with extended infragranular layers at the expense of superficial cortical layers in adult ephrin A5-deficient and EphA4-deficient mice. We suggest that ephrin A5 ligands imported by invading thalamic axons interact with EphA4-expressing RGCs, thereby contributing to the fine-tuning of IPC generation and thus the proper neuronal output for cortical layers.
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Affiliation(s)
- Katrin Gerstmann
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, 07743 Jena, Germany Institute for General Zoology and Animal Physiology, Friedrich-Schiller-University Jena, 07743 Jena, Germany
| | - Daniel Pensold
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, 07743 Jena, Germany
| | - Judit Symmank
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, 07743 Jena, Germany
| | - Mukhran Khundadze
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, 07743 Jena, Germany
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, 07743 Jena, Germany
| | - Jürgen Bolz
- Institute for General Zoology and Animal Physiology, Friedrich-Schiller-University Jena, 07743 Jena, Germany
| | - Geraldine Zimmer
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, 07743 Jena, Germany Institute for General Zoology and Animal Physiology, Friedrich-Schiller-University Jena, 07743 Jena, Germany
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27
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Bordiuk OL, Smith K, Morin PJ, Semënov MV. Cell proliferation and neurogenesis in adult mouse brain. PLoS One 2014; 9:e111453. [PMID: 25375658 PMCID: PMC4222938 DOI: 10.1371/journal.pone.0111453] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/30/2014] [Indexed: 11/18/2022] Open
Abstract
Neurogenesis, the formation of new neurons, can be observed in the adult brain of many mammalian species, including humans. Despite significant progress in our understanding of adult neurogenesis, we are still missing data about the extent and location of production of neural precursors in the adult mammalian brain. We used 5-ethynyl-2'-deoxyuridine (EdU) to map the location of proliferating cells throughout the entire adult mouse brain and found that neurogenesis occurs at two locations in the mouse brain. The larger one we define as the main proliferative zone (MPZ), and the smaller one corresponds to the subgranular zone of the hippocampus. The MPZ can be divided into three parts. The caudate migratory stream (CMS) occupies the middle part of the MPZ. The cable of proliferating cells emanating from the most anterior part of the CMS toward the olfactory bulbs forms the rostral migratory stream. The thin layer of proliferating cells extending posteriorly from the CMS forms the midlayer. We have not found any additional aggregations of proliferating cells in the adult mouse brain that could suggest the existence of other major neurogenic zones in the adult mouse brain.
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Affiliation(s)
- Olivia L. Bordiuk
- New England Geriatric Research Education and Clinical Center, Bedford Division, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, Massachusetts, United States of America
| | - Karen Smith
- New England Geriatric Research Education and Clinical Center, Bedford Division, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, Massachusetts, United States of America
| | - Peter J. Morin
- New England Geriatric Research Education and Clinical Center, Bedford Division, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, Massachusetts, United States of America
| | - Mikhail V. Semënov
- New England Geriatric Research Education and Clinical Center, Bedford Division, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, Massachusetts, United States of America
- * E-mail:
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Rudolph J, Gerstmann K, Zimmer G, Steinecke A, Döding A, Bolz J. A dual role of EphB1/ephrin-B3 reverse signaling on migrating striatal and cortical neurons originating in the preoptic area: should I stay or go away? Front Cell Neurosci 2014; 8:185. [PMID: 25100946 PMCID: PMC4103172 DOI: 10.3389/fncel.2014.00185] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 06/16/2014] [Indexed: 11/23/2022] Open
Abstract
During embryonic development the preoptic area (POA) gives rise to two populations of neurons which are generated at the same time, cortical interneurons and striatal cells. POA-derived cortical interneurons take a superficial path and avoid the developing striatum (Str) when they migrate to their target region. We found that EphB1, which is expressed in the striatal anlage, prevents cortical interneurons from entering the Str via ephrin-B3 reverse signaling. In contrast, for striatal neurons which also express ephrin-B3, EphB1 acts as a stop signal. This dual role of EphB1 is due to differences in ephrin-B3 reverse signaling cascades. For striatal neurons, binding of EphB1 to ephrin-B3 reduces endogenously high levels of pSrc and pFAK, which then causes the cells to stop migration. In contrast, in cortical interneurons EphB1-ephrin-B3 reverse signaling leads to phosphorylation of Src and focal adhesion kinase (FAK) which then mediates repulsion. Consistent with these in vitro findings, in an ephrin-B3 knockout mouse line, we discovered misrouted cortical interneurons in the Str and an over-migration of striatal neurons in their target region. Thus, EphB1/ephrin-B3 reverse signaling has a different impact on two sets of neurons which are generated at the same time and place: it can act as a repulsive cue for migrating neurons or it can terminate neuronal migration, a novel role of the Eph/ephrin system.
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Affiliation(s)
- Judith Rudolph
- Institut für Allgemeine Zoologie und Tierphysiologie, Universität Jena Jena, Germany
| | - Katrin Gerstmann
- Institut für Allgemeine Zoologie und Tierphysiologie, Universität Jena Jena, Germany
| | - Geraldine Zimmer
- Institut für Allgemeine Zoologie und Tierphysiologie, Universität Jena Jena, Germany
| | - André Steinecke
- Institut für Allgemeine Zoologie und Tierphysiologie, Universität Jena Jena, Germany
| | - Annika Döding
- Institut für Allgemeine Zoologie und Tierphysiologie, Universität Jena Jena, Germany
| | - Jürgen Bolz
- Institut für Allgemeine Zoologie und Tierphysiologie, Universität Jena Jena, Germany
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Steinecke A, Gampe C, Zimmer G, Rudolph J, Bolz J. EphA/ephrin A reverse signaling promotes the migration of cortical interneurons from the medial ganglionic eminence. Development 2014; 141:460-71. [DOI: 10.1242/dev.101691] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inhibitory interneurons control the flow of information and synchronization in the cerebral cortex at the circuit level. During embryonic development, multiple subtypes of cortical interneurons are generated in different regions of the ventral telencephalon, such as the medial and caudal ganglionic eminence (MGE and CGE), as well as the preoptic area (POA). These neurons then migrate over long distances towards their cortical target areas. Diverse families of diffusible and cell-bound signaling molecules, including the Eph/ephrin system, regulate and orchestrate interneuron migration. Ephrin A3 and A5, for instance, are expressed at the borders of the pathway of MGE-derived interneurons and prevent these cells from entering inappropriate regions via EphA4 forward signaling. We found that MGE-derived interneurons, in addition to EphA4, also express ephrin A and B ligands, suggesting Eph/ephrin forward and reverse signaling in the same cell. In vitro and in vivo approaches showed that EphA4-induced reverse signaling in MGE-derived interneurons promotes their migration and that this effect is mediated by ephrin A2 ligands. In EphA4 mutant mice, as well as after ephrin A2 knockdown using in utero electroporation, we found delayed interneuron migration at embryonic stages. Thus, besides functions in guiding MGE-derived interneurons to the cortex through forward signaling, here we describe a novel role of the ephrins in driving these neurons to their target via reverse signaling.
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Affiliation(s)
- André Steinecke
- Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, 07743 Jena, Germany
| | - Christin Gampe
- Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, 07743 Jena, Germany
| | - Geraldine Zimmer
- Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, 07743 Jena, Germany
| | - Judith Rudolph
- Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, 07743 Jena, Germany
| | - Jürgen Bolz
- Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, 07743 Jena, Germany
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30
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O'Leary C, Cole SJ, Langford M, Hewage J, White A, Cooper HM. RGMa regulates cortical interneuron migration and differentiation. PLoS One 2013; 8:e81711. [PMID: 24312340 PMCID: PMC3842424 DOI: 10.1371/journal.pone.0081711] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 10/23/2013] [Indexed: 11/24/2022] Open
Abstract
The etiology of neuropsychiatric disorders, including schizophrenia and autism, has been linked to a failure to establish the intricate neural network comprising excitatory pyramidal and inhibitory interneurons during neocortex development. A large proportion of cortical inhibitory interneurons originate in the medial ganglionic eminence (MGE) of the ventral telencephalon and then migrate through the ventral subventricular zone, across the corticostriatal junction, into the embryonic cortex. Successful navigation of newborn interneurons through the complex environment of the ventral telencephalon is governed by spatiotemporally restricted deployment of both chemorepulsive and chemoattractive guidance cues which work in concert to create a migratory corridor. Despite the expanding list of interneuron guidance cues, cues responsible for preventing interneurons from re-entering the ventricular zone of the ganglionic eminences have not been well characterized. Here we provide evidence that the chemorepulsive axon guidance cue, RGMa (Repulsive Guidance Molecule a), may fulfill this function. The ventricular zone restricted expression of RGMa in the ganglionic eminences and the presence of its receptor, Neogenin, in the ventricular zone and on newborn and maturing MGE-derived interneurons implicates RGMa-Neogenin interactions in interneuron differentiation and migration. Using an in vitro approach, we show that RGMa promotes interneuron differentiation by potentiating neurite outgrowth. In addition, using in vitro explant and migration assays, we provide evidence that RGMa is a repulsive guidance cue for newborn interneurons migrating out of the ganglionic eminence ventricular zone. Intriguingly, the alternative Neogenin ligand, Netrin-1, had no effect on migration. However, we observed complete abrogation of RGMa-induced chemorepulsion when newborn interneurons were simultaneously exposed to RGMa and Netrin-1 gradients, suggesting a novel mechanism for the tight regulation of RGMa-guided interneuron migration. We propose that during peak neurogenesis, repulsive RGMa-Neogenin interactions drive interneurons into the migratory corridor and prevent re-entry into the ventricular zone of the ganglionic eminences.
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Affiliation(s)
- Conor O'Leary
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland, Australia
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31
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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: 113] [Impact Index Per Article: 9.4] [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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32
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Marín O. Cellular and molecular mechanisms controlling the migration of neocortical interneurons. Eur J Neurosci 2013; 38:2019-29. [DOI: 10.1111/ejn.12225] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/18/2013] [Accepted: 03/21/2013] [Indexed: 12/16/2022]
Affiliation(s)
- Oscar Marín
- Instituto de Neurociencias; Consejo Superior de Investigaciones Científicas; Universidad Miguel Hernández; Sant Joan d'Alacant; Spain
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33
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Kelsom C, Lu W. Development and specification of GABAergic cortical interneurons. Cell Biosci 2013; 3:19. [PMID: 23618463 PMCID: PMC3668182 DOI: 10.1186/2045-3701-3-19] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/28/2013] [Indexed: 12/21/2022] Open
Abstract
GABAergic interneurons are inhibitory neurons of the nervous system that play a vital role in neural circuitry and activity. They are so named due to their release of the neurotransmitter gamma-aminobutyric acid (GABA), and occupy different areas of the brain. This review will focus primarily on GABAergic interneurons of the mammalian cerebral cortex from a developmental standpoint. There is a diverse amount of cortical interneuronal subtypes that may be categorized by a number of characteristics; this review will classify them largely by the protein markers they express. The developmental origins of GABAergic interneurons will be discussed, as well as factors that influence the complex migration routes that these interneurons must take in order to ultimately localize in the cerebral cortex where they will integrate with the neural circuitry set in place. This review will also place an emphasis on the transcriptional network of genes that play a role in the specification and maintenance of GABAergic interneuron fate. Gaining an understanding of the different aspects of cortical interneuron development and specification, especially in humans, has many useful clinical applications that may serve to treat various neurological disorders linked to alterations in interneuron populations.
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Affiliation(s)
- Corey Kelsom
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Department of Biochemistry and Molecular Biology, University of Southern California, 1425 San Pablo Street, Los Angeles, CA 90033, USA.
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34
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van den Berghe V, Stappers E, Vandesande B, Dimidschstein J, Kroes R, Francis A, Conidi A, Lesage F, Dries R, Cazzola S, Berx G, Kessaris N, Vanderhaeghen P, van Ijcken W, Grosveld FG, Goossens S, Haigh JJ, Fishell G, Goffinet A, Aerts S, Huylebroeck D, Seuntjens E. Directed migration of cortical interneurons depends on the cell-autonomous action of Sip1. Neuron 2013; 77:70-82. [PMID: 23312517 DOI: 10.1016/j.neuron.2012.11.009] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2012] [Indexed: 12/23/2022]
Abstract
GABAergic interneurons mainly originate in the medial ganglionic eminence (MGE) of the embryonic ventral telencephalon (VT) and migrate tangentially to the cortex, guided by membrane-bound and secreted factors. We found that Sip1 (Zfhx1b, Zeb2), a transcription factor enriched in migrating cortical interneurons, is required for their proper differentiation and correct guidance. The majority of Sip1 knockout interneurons fail to migrate to the neocortex and stall in the VT. RNA sequencing reveals that Sip1 knockout interneurons do not acquire a fully mature cortical interneuron identity and contain increased levels of the repulsive receptor Unc5b. Focal electroporation of Unc5b-encoding vectors in the MGE of wild-type brain slices disturbs migration to the neocortex, whereas reducing Unc5b levels in Sip1 knockout slices and brains rescues the migration defect. Our results reveal that Sip1, through tuning of Unc5b levels, is essential for cortical interneuron guidance.
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Affiliation(s)
- Veronique van den Berghe
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, University of Leuven, 3000 Leuven, Belgium
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35
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Fu C, Cawthon B, Clinkscales W, Bruce A, Winzenburger P, Ess KC. GABAergic interneuron development and function is modulated by the Tsc1 gene. Cereb Cortex 2012; 22:2111-9. [PMID: 22021912 PMCID: PMC3412444 DOI: 10.1093/cercor/bhr300] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a genetic disease with severe neurologic and psychiatric manifestations including epilepsy, developmental delay, and autism. Despite much progress in defining abnormal signaling pathways including the contribution of increased mTORC1 signaling, specific abnormalities that underlie the severe neurologic features in TSC remain poorly understood. We hypothesized that epilepsy and autism in TSC result from abnormalities of γ-aminobutyric acidergic (GABAergic) interneurons. To test this hypothesis, we generated conditional knockout mice with selective deletion of the Tsc1 gene in GABAergic interneuron progenitor cells. These interneuron-specific Tsc1 conditional knockout (CKO) mice have impaired growth and decreased survival. Cortical and hippocampal GABAergic interneurons of CKO mice are enlarged and show increased mTORC1 signaling. Total numbers of GABAergic cells are reduced in the cortex with differential reduction of specific GABAergic subtypes. Ectopic clusters of cells with increased mTORC1 signaling are also seen suggesting impaired interneuron migration. The functional consequences of these cellular changes are evident in the decreased seizure threshold on exposure to the proconvulsant flurothyl. These findings support an important role for the Tsc1 gene during GABAergic interneuron development, function, and possibly migration.
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Affiliation(s)
| | | | | | | | | | - Kevin C. Ess
- Department of Neurology
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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36
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North HA, Clifford MA, Donoghue MJ. 'Til Eph do us part': intercellular signaling via Eph receptors and ephrin ligands guides cerebral cortical development from birth through maturation. Cereb Cortex 2012; 23:1765-73. [PMID: 22744705 DOI: 10.1093/cercor/bhs183] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Eph receptors, the largest family of surface-bound receptor tyrosine kinases and their ligands, the ephrins, mediate a wide variety of cellular interactions in most organ systems throughout both development and maturity. In the forming cerebral cortex, Eph family members are broadly and dynamically expressed in particular sets of cortical cells at discrete times. Here, we review the known functions of Eph-mediated intercellular signaling in the generation of progenitors, the migration of maturing cells, the differentiation of neurons, the formation of functional connections, and the choice between life and death during corticogenesis. In synthesizing these results, we posit a signaling paradigm in which cortical cells maintain a life history of Eph-mediated intercellular interactions that guides subsequent cellular decision-making.
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Affiliation(s)
- Hilary A North
- Department of Biology and The Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20057, USA
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37
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GABA through the ages: regulation of cortical function and plasticity by inhibitory interneurons. Neural Plast 2012; 2012:892784. [PMID: 22792496 PMCID: PMC3390141 DOI: 10.1155/2012/892784] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/30/2012] [Accepted: 03/30/2012] [Indexed: 11/17/2022] Open
Abstract
Inhibitory interneurons comprise only about 20% of cortical neurons and thus constitute a clear minority compared to the vast number of excitatory projection neurons. They are, however, an influential minority with important roles in cortical maturation, function, and plasticity. In this paper, we will highlight the functional importance of cortical inhibition throughout brain development, starting with the embryonal formation of the cortex, proceeding by the regulation of sensory cortical plasticity in adulthood, and finishing with the GABA involvement in sensory information processing in old age.
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38
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Terauchi A, Umemori H. Specific sets of intrinsic and extrinsic factors drive excitatory and inhibitory circuit formation. Neuroscientist 2012; 18:271-86. [PMID: 21652588 PMCID: PMC4140556 DOI: 10.1177/1073858411404228] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
How are excitatory (glutamatergic) and inhibitory (GABAergic) synapses established? Do distinct molecular mechanisms direct differentiation of glutamatergic and GABAergic synapses? In the brain, glutamatergic and GABAergic synaptic connections are formed with specific patterns. To establish such precise synaptic patterns, neurons pass through multiple checkpoints during development, such as cell fate determination, cell migration and localization, axonal guidance and target recognition, and synapse formation. Each stage offers key molecules for neurons/synapses to obtain glutamatergic or GABAergic specificity. Some mechanisms are based on intrinsic systems to induce gene expression, whereas others are based on extrinsic systems mediated by cell-cell or axon-target interactions. Recent studies indicate that specific formation of glutamatergic and GABAergic synapses is controlled by the expression or activation of different sets of molecules during development. In this review, the authors outline stages critical to the determination of glutamatergic or GABAergic specificity and describe molecules that act as determinants of specificities in each stage, with a particular focus on the synapse formation stage. They also discuss possible mechanisms underlying glutamatergic and GABAergic synapse formation via synapse-type specific synaptic organizers.
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Affiliation(s)
- Akiko Terauchi
- Molecular & Behavioral Neuroscience Institute, University
of Michigan Medical School, Ann Arbor, MI 48109-2200
| | - Hisashi Umemori
- Molecular & Behavioral Neuroscience Institute, University
of Michigan Medical School, Ann Arbor, MI 48109-2200
- Departments of Biological Chemistry, University of Michigan
Medical School, Ann Arbor, MI 48109-2200
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Faux C, Rakic S, Andrews W, Britto JM. Neurons on the move: migration and lamination of cortical interneurons. Neurosignals 2012; 20:168-89. [PMID: 22572780 DOI: 10.1159/000334489] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The modulation of cortical activity by GABAergic interneurons is required for normal brain function and is achieved through the immense level of heterogeneity within this neuronal population. Cortical interneurons share a common origin in the ventral telencephalon, yet during the maturation process diverse subtypes are generated that form the characteristic laminar arrangement observed in the adult brain. The long distance tangential and short-range radial migration into the cortical plate is regulated by a combination of intrinsic and extrinsic signalling mechanisms, and a great deal of progress has been made to understand these developmental events. In this review, we will summarize current findings regarding the molecular control of subtype specification and provide a detailed account of the migratory cues influencing interneuron migration and lamination. Furthermore, a dysfunctional GABAergic system is associated with a number of neurological and psychiatric conditions, and some of these may have a developmental aetiology with alterations in interneuron generation and migration. We will discuss the notion of additional sources of interneuron progenitors found in human and non-human primates and illustrate how the disruption of early developmental events can instigate a loss in GABAergic function.
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Affiliation(s)
- Clare Faux
- Centre for Neuroscience, University of Melbourne, Parkville, Vic, Australia
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Rodger J, Salvatore L, Migani P. Should I stay or should I go? Ephs and ephrins in neuronal migration. Neurosignals 2012; 20:190-201. [PMID: 22456188 DOI: 10.1159/000333784] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In neuroscience, Ephs and ephrins are perhaps best known for their role in axon guidance. It was first shown in the visual system that graded expression of these proteins is instrumental in providing molecular coordinates that define topographic maps, particularly in the visual system, but also in the auditory, vomeronasal and somatosensory systems as well as in the hippocampus, cerebellum and other structures. Perhaps unsurprisingly, the role of these proteins in regulating cell-cell interactions also has an impact on cell mobility, with evidence that Eph-ephrin interactions segregate cell populations based on contact-mediated attraction or repulsion. Consistent with these studies, evidence has accumulated that Ephs and ephrins play important roles in the migration of specific cell populations in the developing and adult brain. This review focusses on two examples of neuronal migration that require Eph/ephrin signalling - radial and tangential migration of neurons in cortical development and the migration of newly generated neurons along the rostral migratory stream to the olfactory bulb in the adult brain. We discuss the challenge involved in understanding how cells determine whether they respond to signals by migration or axon guidance.
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Affiliation(s)
- Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Animal Biology M317, University of Western Australia, Crawley, WA, Australia
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Antypa M, Faux C, Eichele G, Parnavelas JG, Andrews WD. Differential gene expression in migratory streams of cortical interneurons. Eur J Neurosci 2012; 34:1584-94. [PMID: 22103416 PMCID: PMC3401901 DOI: 10.1111/j.1460-9568.2011.07896.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cortical interneurons originate in the ganglionic eminences of the subpallium and migrate into the cortex in well-defined tangential streams. At the start of corticogenesis, two streams of migrating neurons are evident: a superficial one at the level of the preplate (PPL), and a deeper one at the level of the intermediate zone (IZ). Currently, little is known about the signalling mechanisms that regulate interneuron migration, and almost nothing is known about the molecules that may be involved in their choice of migratory stream. Here, we performed a microarray analysis, comparing the changes in gene expression between cells migrating in the PPL and those migrating in the IZ at embryonic day 13.5. This analysis identified genes, many of them novel, that were upregulated in one of the two streams. Moreover, polymerase chain reaction, in situ hybridization experiments and immunohistochemistry showed the expression of these genes in interneurons migrating within the PPL or IZ, suggesting that they play a role in their migration and choice of stream.
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Affiliation(s)
- Mary Antypa
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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Manent JB, Beguin S, Ganay T, Represa A. Cell-autonomous and cell-to-cell signalling events in normal and altered neuronal migration. Eur J Neurosci 2012; 34:1595-608. [PMID: 22103417 DOI: 10.1111/j.1460-9568.2011.07867.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cerebral cortex is a complex six-layered structure that contains an important diversity of neurons, and has rich local and extrinsic connectivity. Among the mechanisms governing the cerebral cortex construction, neuronal migration is perhaps the most crucial as it ensures the timely formation of specific and selective neuronal circuits. Here, we review the main extrinsic and extrinsic factors involved in regulating neuronal migration in the cortex and describe some environmental factors interfering with their actions.
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Bidirectional ephrinB3/EphA4 signaling mediates the segregation of medial ganglionic eminence- and preoptic area-derived interneurons in the deep and superficial migratory stream. J Neurosci 2012; 31:18364-80. [PMID: 22171039 DOI: 10.1523/jneurosci.4690-11.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The integration of interneuron subtypes into specific microcircuits is essential for proper cortical function. Understanding to what extent interneuron diversity is regulated and maintained during development might help to reveal the principles that govern their role as synchronizing elements as well as causes for dysfunction. Particular interneuron subtypes are generated in a temporally regulated manner in the medial ganglionic eminence (MGE), the caudal ganglionic eminence, and the preoptic area (POA) of the basal telencephalon. Long-range tangential migration from their site of origin to cortical targets is orchestrated by a variety of attractive, repulsive, membrane-bound, and secreted signaling molecules, to establish the critical balance of inhibition and excitation. It remains unknown whether interneurons deriving from distinct domains are predetermined to migrate in particular routes and whether this process underlies cell type-specific regulation. We found that POA- and MGE-derived cortical interneurons migrate within spatially segregated corridors. EphrinB3, expressed in POA-derived interneurons traversing the superficial route, acts as a repellent signal for deeply migrating interneurons born in the MGE, which is mediated by EphA4 forward signaling. In contrast, EphA4 induces repulsive ephrinB3 reverse signaling in interneurons generated in the POA, restricting this population to the superficial path. Perturbation of this bidirectional ephrinB3/EphA4 signaling in vitro and in vivo leads to a partial intermingling of cells in these segregated migratory pathways. Thus, we conclude that cell contact-mediated bidirectional ephrinB3/EphA4 signaling mediates the sorting of MGE- and POA-derived interneurons in the deep and superficial migratory stream.
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