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Iskusnykh IY, Fattakhov N, Li Y, Bihannic L, Kirchner MK, Steshina EY, Northcott PA, Chizhikov VV. Lmx1a is a master regulator of the cortical hem. eLife 2023; 12:e84095. [PMID: 37725078 PMCID: PMC10508884 DOI: 10.7554/elife.84095] [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: 10/11/2022] [Accepted: 09/05/2023] [Indexed: 09/21/2023] Open
Abstract
Development of the nervous system depends on signaling centers - specialized cellular populations that produce secreted molecules to regulate neurogenesis in the neighboring neuroepithelium. In some cases, signaling center cells also differentiate to produce key types of neurons. The formation of a signaling center involves its induction, the maintenance of expression of its secreted molecules, and cell differentiation and migration events. How these distinct processes are coordinated during signaling center development remains unknown. By performing studies in mice, we show that Lmx1a acts as a master regulator to orchestrate the formation and function of the cortical hem (CH), a critical signaling center that controls hippocampus development. Lmx1a co-regulates CH induction, its Wnt signaling, and the differentiation and migration of CH-derived Cajal-Retzius neurons. Combining RNAseq, genetic, and rescue experiments, we identified major downstream genes that mediate distinct Lmx1a-dependent processes. Our work revealed that signaling centers in the mammalian brain employ master regulatory genes and established a framework for analyzing signaling center development.
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Affiliation(s)
- Igor Y Iskusnykh
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Nikolai Fattakhov
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Yiran Li
- Department of Developmental Neurobiology, St. Jude Children's Research HospitalMemphisUnited States
| | - Laure Bihannic
- Department of Developmental Neurobiology, St. Jude Children's Research HospitalMemphisUnited States
| | - Matthew K Kirchner
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Ekaterina Y Steshina
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Paul A Northcott
- Department of Developmental Neurobiology, St. Jude Children's Research HospitalMemphisUnited States
| | - Victor V Chizhikov
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphisUnited States
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2
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Ha TT, Burgess R, Newman M, Moey C, Mandelstam SA, Gardner AE, Ivancevic AM, Pham D, Kumar R, Smith N, Patel C, Malone S, Ryan MM, Calvert S, van Eyk CL, Lardelli M, Berkovic SF, Leventer RJ, Richards LJ, Scheffer IE, Gecz J, Corbett MA. Aicardi Syndrome Is a Genetically Heterogeneous Disorder. Genes (Basel) 2023; 14:1565. [PMID: 37628618 PMCID: PMC10454071 DOI: 10.3390/genes14081565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Aicardi Syndrome (AIC) is a rare neurodevelopmental disorder recognized by the classical triad of agenesis of the corpus callosum, chorioretinal lacunae and infantile epileptic spasms syndrome. The diagnostic criteria of AIC were revised in 2005 to include additional phenotypes that are frequently observed in this patient group. AIC has been traditionally considered as X-linked and male lethal because it almost exclusively affects females. Despite numerous genetic and genomic investigations on AIC, a unifying X-linked cause has not been identified. Here, we performed exome and genome sequencing of 10 females with AIC or suspected AIC based on current criteria. We identified a unique de novo variant, each in different genes: KMT2B, SLF1, SMARCB1, SZT2 and WNT8B, in five of these females. Notably, genomic analyses of coding and non-coding single nucleotide variants, short tandem repeats and structural variation highlighted a distinct lack of X-linked candidate genes. We assessed the likely pathogenicity of our candidate autosomal variants using the TOPflash assay for WNT8B and morpholino knockdown in zebrafish (Danio rerio) embryos for other candidates. We show expression of Wnt8b and Slf1 are restricted to clinically relevant cortical tissues during mouse development. Our findings suggest that AIC is genetically heterogeneous with implicated genes converging on molecular pathways central to cortical development.
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Affiliation(s)
- Thuong T. Ha
- School of Biological Sciences, Faculty of Science, University of Adelaide, Adelaide, SA 5005, Australia
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, An Alliance between SA Pathology and the University of South Australia, Adelaide, SA 5000, Australia
| | - Rosemary Burgess
- Epilepsy Research Centre, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia (S.F.B.); (I.E.S.)
| | - Morgan Newman
- Alzheimer’s Disease Genetics Laboratory, School of Biological Sciences, Faculty of Science, University of Adelaide, Adelaide, SA 5005, Australia (M.L.)
| | - Ching Moey
- The Queensland Brain Institute, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4000, Australia
| | - Simone A. Mandelstam
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medical Imaging, The Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Alison E. Gardner
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
| | - Atma M. Ivancevic
- Department of Molecular, Cellular, and Developmental Biology, College of Arts and Sciences, University of Colorado, Boulder, CO 80309, USA
| | - Duyen Pham
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
| | - Raman Kumar
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
| | - Nicholas Smith
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
- Department of Neurology, Women’s and Children’s Hospital, North Adelaide, SA 5006, Australia
| | - Chirag Patel
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Herston, QLD 4029, Australia
| | - Stephen Malone
- Queensland Children’s Hospital, South Brisbane, QLD 4101, Australia
| | - Monique M. Ryan
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Neurology, The Royal Children’s Hospital, Parkville, VIC 3052, Australia
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
| | - Sophie Calvert
- Department of Neurosciences, Queensland Children’s Hospital, South Brisbane, QLD 4101, Australia;
| | - Clare L. van Eyk
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
| | - Michael Lardelli
- Alzheimer’s Disease Genetics Laboratory, School of Biological Sciences, Faculty of Science, University of Adelaide, Adelaide, SA 5005, Australia (M.L.)
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia (S.F.B.); (I.E.S.)
| | - Richard J. Leventer
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Neurology, The Royal Children’s Hospital, Parkville, VIC 3052, Australia
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
| | - Linda J. Richards
- The Queensland Brain Institute, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4000, Australia
- Department of Neuroscience, School of Medicine, Washington University, St Louis, MO 63110, USA
| | - Ingrid E. Scheffer
- Epilepsy Research Centre, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia (S.F.B.); (I.E.S.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Neurology, The Royal Children’s Hospital, Parkville, VIC 3052, Australia
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC 3052, Australia
| | - Jozef Gecz
- School of Biological Sciences, Faculty of Science, University of Adelaide, Adelaide, SA 5005, Australia
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
- South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia
| | - Mark A. Corbett
- Adelaide Medical School and Robinson Research Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia (M.A.C.)
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3
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Da Silva F, Niehrs C. Multimodal Wnt signalling in the mouse neocortex. Cells Dev 2023; 174:203838. [PMID: 37060946 DOI: 10.1016/j.cdev.2023.203838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/30/2023] [Accepted: 04/08/2023] [Indexed: 04/17/2023]
Abstract
The neocortex is the site of higher cognitive functions and its development is tightly regulated by cell signalling pathways. Wnt signalling is inexorably linked with neocortex development but its precise role remains unclear. Most studies demonstrate that Wnt/β-catenin regulates neural progenitor self-renewal but others suggest it can also promote differentiation. Wnt/STOP signalling is a novel branch of the Wnt pathway that stabilizes proteins during G2/M by inhibiting glycogen synthase kinase 3 (GSK3)-mediated protein degradation. Recent data from Da Silva et al. (2021) demonstrate that Wnt/STOP is involved in neocortex development where, by stabilizing the neurogenic transcription factors Sox4 and Sox11, it promotes neural progenitor differentiation. The authors also show that Wnt/STOP regulates asymmetric cell division and cell cycle dynamics in apical and basal progenitors, respectively. This study reveals a division of labour in the Wnt signalling pathway by suggesting that Wnt/STOP is the primary driver of cortical neurogenesis while Wnt/β-catenin is mainly responsible for self-renewal. These results resolve a decades-old question on the role of Wnt signalling in cortical neural progenitors.
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Affiliation(s)
- Fabio Da Silva
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg, Germany
| | - Christof Niehrs
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg, Germany; Institute of Molecular Biology (IMB), 55128 Mainz, Germany.
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4
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Moore SA, Iulianella A. Development of the mammalian cortical hem and its derivatives: the choroid plexus, Cajal-Retzius cells and hippocampus. Open Biol 2021; 11:210042. [PMID: 33947245 PMCID: PMC8097212 DOI: 10.1098/rsob.210042] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The dorsal medial region of the developing mammalian telencephalon plays a central role in the patterning of the adjacent brain regions. This review describes the development of this specialized region of the vertebrate brain, called the cortical hem, and the formation of the various cells and structures it gives rise to, including the choroid plexus, Cajal–Retzius cells and the hippocampus. We highlight the ontogenic processes that create these different forebrain derivatives from their shared embryonic origin and discuss the key signalling pathways and molecules that influence the patterning of the cortical hem. These include BMP, Wnt, FGF and Shh signalling pathways acting with Homeobox factors to carve the medial telencephalon into district progenitor regions, which in turn give rise to the choroid plexus, dentate gyrus and hippocampus. We then link the formation of the lateral ventricle choroid plexus with embryonic and postnatal neurogenesis in the hippocampus.
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Affiliation(s)
- Samantha A Moore
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, and Brain Repair Centre, Life Science Research Institute, 1348 Summer Street, Halifax, Nova Scotia, Canada, B3H4R2
| | - Angelo Iulianella
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, and Brain Repair Centre, Life Science Research Institute, 1348 Summer Street, Halifax, Nova Scotia, Canada, B3H4R2
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5
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Mercurio S, Alberti C, Serra L, Meneghini S, Berico P, Bertolini J, Becchetti A, Nicolis SK. An early Sox2-dependent gene expression programme required for hippocampal dentate gyrus development. Open Biol 2021; 11:200339. [PMID: 33622105 PMCID: PMC8061699 DOI: 10.1098/rsob.200339] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The hippocampus is a brain area central for cognition. Mutations in the human SOX2 transcription factor cause neurodevelopmental defects, leading to intellectual disability and seizures, together with hippocampal dysplasia. We generated an allelic series of Sox2 conditional mutations in mouse, deleting Sox2 at different developmental stages. Late Sox2 deletion (from E11.5, via Nestin-Cre) affects only postnatal hippocampal development; earlier deletion (from E10.5, Emx1-Cre) significantly reduces the dentate gyrus (DG), and the earliest deletion (from E9.5, FoxG1-Cre) causes drastic abnormalities, with almost complete absence of the DG. We identify a set of functionally interconnected genes (Gli3, Wnt3a, Cxcr4, p73 and Tbr2), known to play essential roles in hippocampal embryogenesis, which are downregulated in early Sox2 mutants, and (Gli3 and Cxcr4) directly controlled by SOX2; their downregulation provides plausible molecular mechanisms contributing to the defect. Electrophysiological studies of the Emx1-Cre mouse model reveal altered excitatory transmission in CA1 and CA3 regions.
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Affiliation(s)
- Sara Mercurio
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Chiara Alberti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Linda Serra
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Simone Meneghini
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Pietro Berico
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Jessica Bertolini
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Silvia K Nicolis
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
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6
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Ni Y, Liu B, Wu X, Liu J, Ba R, Zhao C. FOXG1 Directly Suppresses Wnt5a During the Development of the Hippocampus. Neurosci Bull 2021; 37:298-310. [PMID: 33389683 DOI: 10.1007/s12264-020-00618-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/19/2020] [Indexed: 12/17/2022] Open
Abstract
The Wnt signaling pathway plays key roles in various developmental processes. Wnt5a, which activates the non-canonical pathway, has been shown to be particularly important for axon guidance and outgrowth as well as dendrite morphogenesis. However, the mechanism underlying the regulation of Wnt5a remains unclear. Here, through conditional disruption of Foxg1 in hippocampal progenitors and postmitotic neurons achieved by crossing Foxg1fl/fl with Emx1-Cre and Nex-Cre, respectively, we found that Wnt5a rather than Wnt3a/Wnt2b was markedly upregulated. Overexpression of Foxg1 had the opposite effects along with decreased dendritic complexity and reduced mossy fibers in the hippocampus. We further demonstrated that FOXG1 directly repressed Wnt5a by binding to its promoter and one enhancer site. These results expand our knowledge of the interaction between Foxg1 and Wnt signaling and help elucidate the mechanisms underlying hippocampal development.
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Affiliation(s)
- Yang Ni
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Bin Liu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Xiaojing Wu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Junhua Liu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Ru Ba
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China.
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7
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Smith R, Huang YT, Tian T, Vojtasova D, Mesalles-Naranjo O, Pollard SM, Pratt T, Price DJ, Fotaki V. The Transcription Factor Foxg1 Promotes Optic Fissure Closure in the Mouse by Suppressing Wnt8b in the Nasal Optic Stalk. J Neurosci 2017; 37:7975-7993. [PMID: 28729440 PMCID: PMC5559767 DOI: 10.1523/jneurosci.0286-17.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/25/2017] [Accepted: 07/02/2017] [Indexed: 11/21/2022] Open
Abstract
During vertebrate eye morphogenesis, a transient fissure forms at its inferior part, known as the optic fissure. This will gradually close, giving rise to a healthy, spherical optic cup. Failure of the optic fissure to close gives rise to an ocular disorder known as coloboma. During this developmental process, Foxg1 is expressed in the optic neuroepithelium, with highest levels of expression in the nasal optic stalk. Foxg1-/- mutant mice have microphthalmic eyes with a large ventral coloboma. We found Wnt8b expression upregulated in the Foxg1-/- optic stalk and hypothesized that, similar to what is observed in telencephalic development, Foxg1 directs development of the optic neuroepithelium through transcriptional suppression of Wnt8b To test this, we generated Foxg1-/-;Wnt8b-/- double mutants of either sex and found that the morphology of the optic cup and stalk and the closure of the optic fissure were substantially rescued in these embryos. This rescue correlates with restored Pax2 expression in the anterior tip of the optic fissure. In addition, although we do not find evidence implicating altered proliferation in the rescue, we observe a significant increase in apoptotic cell density in Foxg1-/-;Wnt8b-/- double mutants compared with the Foxg1-/- single mutant. Upregulation of Wnt/β-catenin target molecules in the optic cup and stalk may underlie the molecular and morphological defects in the Foxg1-/- mutant. Our results show that proper optic fissure closure relies on Wnt8b suppression by Foxg1 in the nasal optic stalk to maintain balanced apoptosis and Pax2 expression in the nasal and temporal edges of the fissure.SIGNIFICANCE STATEMENT Coloboma is an ocular disorder that may result in a loss of visual acuity and accounts for ∼10% of childhood blindness. It results from errors in the sealing of the optic fissure (OF), a transient structure at the bottom of the eye. Here, we investigate the colobomatous phenotype of the Foxg1-/- mutant mouse. We identify upregulated expression of Wnt8b in the optic stalk of Foxg1-/- mutants before OF closure initiates. Foxg1-/-;Wnt8b-/- double mutants show a substantial rescue of the Foxg1-/- coloboma phenotype, which correlates with a rescue in molecular and cellular defects of Foxg1-/- mutants. Our results unravel a new role of Foxg1 in promoting OF closure providing additional knowledge about the molecules and cellular mechanisms underlying coloboma formation.
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Affiliation(s)
- Rowena Smith
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom
| | - Yu-Ting Huang
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom
| | - Tian Tian
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom
| | - Dominika Vojtasova
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom
| | - Oscar Mesalles-Naranjo
- Information Service Division, NHS National Services Scotland, Edinburgh, EH12 9EB, United Kingdom
| | - Steven M Pollard
- Medical Research Council Centre for Regenerative Medicine, Edinburgh, EH16 4UU, United Kingdom, and
- Edinburgh Cancer Research UK Cancer Centre, Edinburgh, EH16 4UU, United Kingdom
| | - Thomas Pratt
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom
| | - David J Price
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom
| | - Vassiliki Fotaki
- Edinburgh Medical School, Biomedical Sciences, Centre for Integrative Physiology, Edinburgh, EH8 9XD, United Kingdom,
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8
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Mulligan KA, Cheyette BNR. Neurodevelopmental Perspectives on Wnt Signaling in Psychiatry. MOLECULAR NEUROPSYCHIATRY 2017; 2:219-246. [PMID: 28277568 DOI: 10.1159/000453266] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mounting evidence indicates that Wnt signaling is relevant to pathophysiology of diverse mental illnesses including schizophrenia, bipolar disorder, and autism spectrum disorder. In the 35 years since Wnt ligands were first described, animal studies have richly explored how downstream Wnt signaling pathways affect an array of neurodevelopmental processes and how their disruption can lead to both neurological and behavioral phenotypes. Recently, human induced pluripotent stem cell (hiPSC) models have begun to contribute to this literature while pushing it in increasingly translational directions. Simultaneously, large-scale human genomic studies are providing evidence that sequence variation in Wnt signal pathway genes contributes to pathogenesis in several psychiatric disorders. This article reviews neurodevelopmental and postneurodevelopmental functions of Wnt signaling, highlighting mechanisms, whereby its disruption might contribute to psychiatric illness, and then reviews the most reliable recent genetic evidence supporting that mutations in Wnt pathway genes contribute to psychiatric illness. We are proponents of the notion that studies in animal and hiPSC models informed by the human genetic data combined with the deep knowledge base and tool kits generated over the last several decades of basic neurodevelopmental research will yield near-term tangible advances in neuropsychiatry.
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Affiliation(s)
- Kimberly A Mulligan
- Department of Biological Sciences, California State University, Sacramento, CA, USA
| | - Benjamin N R Cheyette
- Department of Psychiatry, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
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9
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Adutwum-Ofosu KK, Magnani D, Theil T, Price DJ, Fotaki V. The molecular and cellular signatures of the mouse eminentia thalami support its role as a signalling centre in the developing forebrain. Brain Struct Funct 2015; 221:3709-27. [PMID: 26459142 PMCID: PMC5009181 DOI: 10.1007/s00429-015-1127-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/30/2015] [Indexed: 12/20/2022]
Abstract
The mammalian eminentia thalami (EmT) (or thalamic eminence) is an embryonic forebrain structure of unknown function. Here, we examined the molecular and cellular properties of the mouse EmT. We first studied mRNA expression of signalling molecules and found that the EmT is a structure, rich in expression of secreted factors, with Wnts being the most abundantly detected. We then examined whether EmT tissue could induce cell fate changes when grafted ectopically. For this, we transplanted EmT tissue from a tau-GFP mouse to the ventral telencephalon of a wild type host, a telencephalic region where Wnt signalling is not normally active but which we showed in culture experiments is competent to respond to Wnts. We observed that the EmT was able to induce in adjacent ventral telencephalic cells ectopic expression of Lef1, a transcriptional activator and a target gene of the Wnt/β-catenin pathway. These Lef1-positive;GFP-negative cells expressed the telencephalic marker Foxg1 but not Ascl1, which is normally expressed by ventral telencephalic cells. These results suggest that the EmT has the capacity to activate Wnt/β-catenin signalling in the ventral telencephalon and to suppress ventral telencephalic gene expression. Altogether, our data support a role of the EmT as a signalling centre in the developing mouse forebrain.
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Affiliation(s)
- Kevin Kofi Adutwum-Ofosu
- The University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Department of Anatomy, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Dario Magnani
- The University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Thomas Theil
- The University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - David J Price
- The University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Vassiliki Fotaki
- The University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
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10
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Wnt1 signal determines the patterning of the diencephalic dorso-ventral axis. Brain Struct Funct 2015; 221:3693-708. [PMID: 26452989 DOI: 10.1007/s00429-015-1126-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 09/30/2015] [Indexed: 12/31/2022]
Abstract
The diencephalon is a complex brain area that derives from the caudal region of the prosencephalon. This structure is divided into four longitudinal neuroepithelial zones: roof, alar, basal and floor plates, which constitute its dorso-ventral (DV) columnar domains. Morphogenetic differences between alar and basal plates in the prosencephalon and mesencephalon contribute to the characteristic expansion of alar plate derivatives in the brain and the formation of the cephalic flexure. Although differential histogenesis among DV regions seems to be relevant in understanding structural and functional complexity of the brain, most of our knowledge about DV regionalization comes from the spinal cord development. Therefore, it seems of interest to study the molecular mechanisms that govern DV patterning in the diencephalon, the brain region where strong differences in size and complexity between alar and basal derivatives are evident in all vertebrates. Different morphogenetic signals, which induce specific progenitors fate to the neighboring epithelium, are involved in the spinal cord DV patterning. To study if Wnt1, one of these signaling molecules, has a role for the establishment of the diencephalic longitudinal domains, we carried out gain- and loss-of-function experiments, using mice and chick embryos. Our results demonstrated functional differences in the molecular mechanisms downstream of Wnt1 function in the diencephalon, in relation to the spinal cord. We further demonstrated that Bmp4 signal induces Wnt1 expression in the diencephalon, unraveling a new molecular regulatory code downstream of primary dorsalizing signals to control ventral regionalization in the diencephalon.
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11
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Kuwahara A, Sakai H, Xu Y, Itoh Y, Hirabayashi Y, Gotoh Y. Tcf3 represses Wnt-β-catenin signaling and maintains neural stem cell population during neocortical development. PLoS One 2014; 9:e94408. [PMID: 24832538 PMCID: PMC4022625 DOI: 10.1371/journal.pone.0094408] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/15/2014] [Indexed: 01/02/2023] Open
Abstract
During mouse neocortical development, the Wnt–β-catenin signaling pathway plays essential roles in various phenomena including neuronal differentiation and proliferation of neural precursor cells (NPCs). Production of the appropriate number of neurons without depletion of the NPC population requires precise regulation of the balance between differentiation and maintenance of NPCs. However, the mechanism that suppresses Wnt signaling to prevent premature neuronal differentiation of NPCs is poorly understood. We now show that the HMG box transcription factor Tcf3 (also known as Tcf7l1) contributes to this mechanism. Tcf3 is highly expressed in undifferentiated NPCs in the mouse neocortex, and its expression is reduced in intermediate neuronal progenitors (INPs) committed to the neuronal fate. We found Tcf3 to be a repressor of Wnt signaling in neocortical NPCs in a reporter gene assay. Tcf3 bound to the promoter of the proneural bHLH gene Neurogenin1 (Neurog1) and repressed its expression. Consistent with this, Tcf3 repressed neuronal differentiation and increased the self-renewal activity of NPCs. We also found that Wnt signal stimulation reduces the level of Tcf3, and increases those of Tcf1 (also known as Tcf7) and Lef1, positive mediators of Wnt signaling, in NPCs. Together, these results suggest that Tcf3 antagonizes Wnt signaling in NPCs, thereby maintaining their undifferentiated state in the neocortex and that Wnt signaling promotes the transition from Tcf3-mediated repression to Tcf1/Lef1-mediated enhancement of Wnt signaling, constituting a positive feedback loop that facilitates neuronal differentiation.
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Affiliation(s)
- Atsushi Kuwahara
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Sakai
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yuanjiang Xu
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yasuhiro Itoh
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yusuke Hirabayashi
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
- * E-mail:
| | - Yukiko Gotoh
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
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Fotaki V, Smith R, Pratt T, Price DJ. Foxg1 is required to limit the formation of ciliary margin tissue and Wnt/β-catenin signalling in the developing nasal retina of the mouse. Dev Biol 2013; 380:299-313. [PMID: 23624311 PMCID: PMC3722486 DOI: 10.1016/j.ydbio.2013.04.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 04/15/2013] [Accepted: 04/16/2013] [Indexed: 12/23/2022]
Abstract
The ciliary margin (CM) develops in the peripheral retina and gives rise to the iris and the ciliary body. The Wnt/β-catenin signalling pathway has been implicated in ciliary margin development. Here, we tested the hypothesis that in the developing mouse retina Foxg1 is responsible for suppressing the Wnt/β-catenin pathway and restricting CM development. We showed that there is excess CM tissue in Foxg1−/− null embryos and this expansion is more pronounced in the nasal retina where Foxg1 normally shows its highest expression levels. Results on expression of a reporter allele for Wnt/β-catenin signalling and of Lef1, a target of Wnt/β-catenin signalling, displayed significant upregulation of this pathway in Foxg1−/− nulls at embryonic days 12.5 and 14.5. Interestingly, this upregulation was observed specifically in the nasal retina, where normally very few Wnt-responsive cells are observed. These results indicate a suppressive role of Foxg1 on this signalling pathway. Our results reveal a new role of Foxg1 in limiting CM development in the nasal peripheral retina and add a new molecular player in the developmental network involved in CM specification. Foxg1 is expressed in a nasal-high to temporal-low gradient in developing retina. Ciliary margin expansion is observed nasally in the Foxg1−/− mutant retina. Wnt/β-catenin signalling is upregulated in the Foxg1−/− peripheral retina nasally. A new role of Foxg1 in controlling ciliary margin development is proposed.
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Affiliation(s)
- Vassiliki Fotaki
- University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.
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13
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Competing signals drive telencephalon diversity. Nat Commun 2013; 4:1745. [DOI: 10.1038/ncomms2753] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 03/14/2013] [Indexed: 02/06/2023] Open
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Amaniti EM, Hasenpusch-Theil K, Li Z, Magnani D, Kessaris N, Mason JO, Theil T. Gli3 is required in Emx1+ progenitors for the development of the corpus callosum. Dev Biol 2013; 376:113-24. [PMID: 23396189 DOI: 10.1016/j.ydbio.2013.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/29/2013] [Accepted: 02/01/2013] [Indexed: 10/27/2022]
Abstract
The corpus callosum (CC) is the largest commissure in the forebrain and mediates the transfer of sensory, motor and cognitive information between the cerebral hemispheres. During CC development, a number of strategically located glial and neuronal guidepost structures serve to guide callosal axons across the midline at the corticoseptal boundary (CSB). Correct positioning of these guideposts requires the Gli3 gene, mutations of which result in callosal defects in humans and mice. However, as Gli3 is widely expressed during critical stages of forebrain development, the precise temporal and spatial requirements for Gli3 function in callosal development remain unclear. Here, we used a conditional mouse mutant approach to inactivate Gli3 in specific regions of the developing telencephalon in order to delineate the domain(s) in which Gli3 is required for normal development of the corpus callosum. Inactivation of Gli3 in the septum or in the medial ganglionic eminence had no effect on CC formation, however Gli3 inactivation in the developing cerebral cortex led to the formation of a severely hypoplastic CC at E18.5 due to a severe disorganization of midline guideposts. Glial wedge cells translocate prematurely and Slit1/2 are ectopically expressed in the septum. These changes coincide with altered Fgf and Wnt/β-catenin signalling during CSB formation. Collectively, these data demonstrate a crucial role for Gli3 in cortical progenitors to control CC formation and indicate how defects in CSB formation affect the positioning of callosal guidepost cells.
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Affiliation(s)
- Eleni-Maria Amaniti
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, United Kingdom
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15
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Mulligan KA, Cheyette BNR. Wnt signaling in vertebrate neural development and function. J Neuroimmune Pharmacol 2012; 7:774-87. [PMID: 23015196 DOI: 10.1007/s11481-012-9404-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/10/2012] [Indexed: 02/03/2023]
Abstract
Members of the Wnt family of secreted signaling proteins influence many aspects of neural development and function. Wnts are required from neural induction and axis formation to axon guidance and synapse development, and even help modulate synapse activity. Wnt proteins activate a variety of downstream signaling pathways and can induce a similar variety of cellular responses, including gene transcription changes and cytoskeletal rearrangements. This review provides an introduction to Wnt signaling pathways and discusses current research on their roles in vertebrate neural development and function.
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Affiliation(s)
- Kimberly A Mulligan
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
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Saulnier A, Keruzore M, De Clercq S, Bar I, Moers V, Magnani D, Walcher T, Filippis C, Kricha S, Parlier D, Viviani L, Matson CK, Nakagawa Y, Theil T, Götz M, Mallamaci A, Marine JC, Zarkower D, Bellefroid EJ. The doublesex homolog Dmrt5 is required for the development of the caudomedial cerebral cortex in mammals. ACTA ACUST UNITED AC 2012; 23:2552-67. [PMID: 22923088 DOI: 10.1093/cercor/bhs234] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Regional patterning of the cerebral cortex is initiated by morphogens secreted by patterning centers that establish graded expression of transcription factors within cortical progenitors. Here, we show that Dmrt5 is expressed in cortical progenitors in a high-caudomedial to low-rostrolateral gradient. In its absence, the cortex is strongly reduced and exhibits severe abnormalities, including agenesis of the hippocampus and choroid plexus and defects in commissural and thalamocortical tracts. Loss of Dmrt5 results in decreased Wnt and Bmp in one of the major telencephalic patterning centers, the dorsomedial telencephalon, and in a reduction of Cajal-Retzius cells. Expression of the dorsal midline signaling center-dependent transcription factors is downregulated, including Emx2, which promotes caudomedial fates, while the rostral determinant Pax6, which is inhibited by midline signals, is upregulated. Consistently, Dmrt5(-/-) brains exhibit patterning defects with a dramatic reduction of the caudomedial cortex. Dmrt5 is increased upon the activation of Wnt signaling and downregulated in Gli3(xt/xt) mutants. We conclude that Dmrt5 is a novel Wnt-dependent transcription factor required for early cortical development and that it may regulate initial cortical patterning by promoting dorsal midline signaling center formation and thereby helping to establish the graded expression of the other transcription regulators of cortical identity.
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Affiliation(s)
- Amandine Saulnier
- Laboratoire de Génétique du Développement, Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires (IBMM), Gosselies, Belgium
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Abstract
Components of the Wnt signaling pathway are expressed in a tightly regulated and spatially specific manner during development of the forebrain, and Wnts are key regulators of regional forebrain identity. Wnt signaling from the cortical hem regulates the expansion and cell-type specification of the adjacent neuroepithelium and, in conjunction with Bmp, Fgf, and Shh signaling, controls dorsal-ventral forebrain patterning. Subsequently, Wnt signaling dynamically regulates the behavior of cortical progenitor cells, initially promoting the expansion of radial glia progenitor cells and later inducing neurogenesis by promoting terminal differentiation of intermediate progenitor cells. A role for Wnt signaling in cell-type specification has also been proposed.
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Affiliation(s)
- Susan J Harrison-Uy
- Department of Neurology, University of California, San Francisco, California 94143, USA
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18
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Hasenpusch-Theil K, Magnani D, Amaniti EM, Han L, Armstrong D, Theil T. Transcriptional analysis of Gli3 mutants identifies Wnt target genes in the developing hippocampus. ACTA ACUST UNITED AC 2012; 22:2878-93. [PMID: 22235033 DOI: 10.1093/cercor/bhr365] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Early development of the hippocampus, which is essential for spatial memory and learning, is controlled by secreted signaling molecules of the Wnt gene family and by Wnt/β-catenin signaling. Despite its importance, little is known, however, about Wnt-regulated genes during hippocampal development. Here, we used the Gli3 mutant mouse extra-toes (Xt(J)), in which Wnt gene expression in the forebrain is severely affected, as a tool in a microarray analyses to identify potential Wnt target genes. This approach revealed 53 candidate genes with restricted or graded expression patterns in the dorsomedial telencephalon. We identified conserved Tcf/Lef-binding sites in telencephalon-specific enhancers of several of these genes, including Dmrt3, Gli3, Nfia, and Wnt8b. Binding of Lef1 to these sites was confirmed using electrophoretic mobility shift assays. Mutations in these Tcf/Lef-binding sites disrupted or reduced enhancer activity in vivo. Moreover, ectopic activation of Wnt/β-catenin signaling in an ex vivo explant system led to increased telencephalic expression of these genes. Finally, conditional inactivation of Gli3 results in defective hippocampal growth. Collectively, these data strongly suggest that we have identified a set of direct Wnt target genes in the developing hippocampus and provide inside into the genetic hierarchy underlying Wnt-regulated hippocampal development.
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Wei Q, Condie BG. A focused in situ hybridization screen identifies candidate transcriptional regulators of thymic epithelial cell development and function. PLoS One 2011; 6:e26795. [PMID: 22087235 PMCID: PMC3210126 DOI: 10.1371/journal.pone.0026795] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 10/04/2011] [Indexed: 12/16/2022] Open
Abstract
Background Thymic epithelial cells (TECs) are necessary for normal T cell development. Currently, one transcription factor, Foxn1 is known to be necessary for the progression of fetal TEC differentiation. However, some aspects of fetal TEC differentiation occur in Foxn1 mutants, suggesting the existence of additional transcriptional regulators of TEC differentiation. The goal of this study was to identify some of the additional candidate transcription factors that may be involved in the specification and/or differentiation of TECs during fetal development. Methodology/Principal Findings We identified candidate fetal TEC transcriptional regulators via data and text mining. From our data mining we selected the transcription factors Foxg1, Isl1, Gata3, Nkx2-5, Nkx2-6 and Sox2 for further studies. Whole mount in situ hybridizations confirmed the expression of these transcription factors within subdomains of the third pharyngeal pouch from E9.5–E10.5. By E11.5 days Foxg1 and Isl1 transcripts were the only mRNAs from this group of genes detected exclusively within the thymus domain of the third pouch. Based on this initial in situ hybridization analysis, we focused on defining the expression of Foxg1 and Isl1 during multiple stages of thymus development and TEC differentiation. We found that Foxg1 and Isl1 are specifically expressed in differentiating TECs during fetal and postnatal stages of thymus development. In addition, we found differential expression of Islet1 and Foxn1 within the fetal and postnatal TEC population. Conclusions/Significance Our studies have identified two developmental transcription factors that are excellent candidate regulators of thymic epithelial cell specification and differentiation during fetal development. Our results suggest that Foxg1 and Isl1 may play a role in the regulation of TEC differentiation during fetal and postnatal stages. Our results also demonstrate heterogeneity of TECs marked by the differential expression of transcription factors, potentially providing new insights into the regulation of TEC differentiation.
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Affiliation(s)
- Qiaozhi Wei
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Brian G. Condie
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Selvadurai HJ, Mason JO. Wnt/β-catenin signalling is active in a highly dynamic pattern during development of the mouse cerebellum. PLoS One 2011; 6:e23012. [PMID: 21857982 PMCID: PMC3152553 DOI: 10.1371/journal.pone.0023012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 07/08/2011] [Indexed: 02/02/2023] Open
Abstract
The adult cerebellum is composed of several distinct cell types with well defined developmental origins. However, the molecular mechanisms that govern the generation of these cell types are only partially resolved. Wnt/β-catenin signalling has a wide variety of roles in generation of the central nervous system, though the specific activity of this pathway during cerebellum development is not well understood. Here, we present data that delineate the spatio-temporal specific pattern of Wnt/β-catenin signaling during mouse cerebellum development between E12.5 and P21. Using the BAT-gal Wnt/β-catenin reporter mouse, we found that Wnt/β-catenin activity is present transiently at the embryonic rhombic lip but not at later stages during the expansion of cell populations that arise from there. At late embryonic and early postnatal stages, Wnt/β-catenin activity shifts to the cerebellar ventricular zone and to cells arising from this germinal centre. Subsequently, the expression pattern becomes progressively restricted to Bergmann glial cells, which show expression of the reporter at P21. These results indicate a variety of potential functions for Wnt/β-catenin activity during cerebellum development.
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Affiliation(s)
- Hayden J Selvadurai
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
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