1
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Kiral FR, Choe M, Park IH. Diencephalic organoids - A key to unraveling development, connectivity, and pathology of the human diencephalon. Front Cell Neurosci 2023; 17:1308479. [PMID: 38130869 PMCID: PMC10733522 DOI: 10.3389/fncel.2023.1308479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
The diencephalon, an integral component of the forebrain, governs a spectrum of crucial functions, ranging from sensory processing to emotional regulation. Yet, unraveling its unique development, intricate connectivity, and its role in neurodevelopmental disorders has long been hampered by the scarcity of human brain tissue and ethical constraints. Recent advancements in stem cell technology, particularly the emergence of brain organoids, have heralded a new era in neuroscience research. Although most brain organoid methodologies have hitherto concentrated on directing stem cells toward telencephalic fates, novel techniques now permit the generation of region-specific brain organoids that faithfully replicate precise diencephalic identities. These models mirror the complexity of the human diencephalon, providing unprecedented opportunities for investigating diencephalic development, functionality, connectivity, and pathophysiology in vitro. This review summarizes the development, function, and connectivity of diencephalic structures and touches upon developmental brain disorders linked to diencephalic abnormalities. Furthermore, it presents current diencephalic organoid models and their applications in unraveling the intricacies of diencephalic development, function, and pathology in humans. Lastly, it highlights thalamocortical assembloid models, adept at capturing human-specific aspects of thalamocortical connections, along with their relevance in neurodevelopmental disorders.
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Affiliation(s)
| | | | - In-Hyun Park
- Interdepartmental Neuroscience Program, Department of Genetics, Yale Stem Cell Center, Yale Child Study Center, Wu Tsai Institute, Yale School of Medicine, New Haven, CT, United States
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2
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Kim CN, Shin D, Wang A, Nowakowski TJ. Spatiotemporal molecular dynamics of the developing human thalamus. Science 2023; 382:eadf9941. [PMID: 37824646 PMCID: PMC10758299 DOI: 10.1126/science.adf9941] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 09/15/2023] [Indexed: 10/14/2023]
Abstract
The thalamus plays a central coordinating role in the brain. Thalamic neurons are organized into spatially distinct nuclei, but the molecular architecture of thalamic development is poorly understood, especially in humans. To begin to delineate the molecular trajectories of cell fate specification and organization in the developing human thalamus, we used single-cell and multiplexed spatial transcriptomics. We show that molecularly defined thalamic neurons differentiate in the second trimester of human development and that these neurons organize into spatially and molecularly distinct nuclei. We identified major subtypes of glutamatergic neuron subtypes that are differentially enriched in anatomically distinct nuclei and six subtypes of γ-aminobutyric acid-mediated (GABAergic) neurons that are shared and distinct across thalamic nuclei.
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Affiliation(s)
- Chang N Kim
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
- Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA 94143, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA
| | - David Shin
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
- Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA 94143, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA
| | - Albert Wang
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
| | - Tomasz J Nowakowski
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
- Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA 94143, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA
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3
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Kim CN, Shin D, Wang A, Nowakowski TJ. Spatiotemporal molecular dynamics of the developing human thalamus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554174. [PMID: 37662287 PMCID: PMC10473600 DOI: 10.1101/2023.08.21.554174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The thalamus plays a central coordinating role in the brain. Thalamic neurons are organized into spatially-distinct nuclei, but the molecular architecture of thalamic development is poorly understood, especially in humans. To begin to delineate the molecular trajectories of cell fate specification and organization in the developing human thalamus, we used single cell and multiplexed spatial transcriptomics. Here we show that molecularly-defined thalamic neurons differentiate in the second trimester of human development, and that these neurons organize into spatially and molecularly distinct nuclei. We identify major subtypes of glutamatergic neuron subtypes that are differentially enriched in anatomically distinct nuclei. In addition, we identify six subtypes of GABAergic neurons that are shared and distinct across thalamic nuclei. One-Sentence Summary Single cell and spatial profiling of the developing thalamus in the first and second trimester yields molecular mechanisms of thalamic nuclei development.
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4
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Zhang W, Luo P, Liu X, Cheng R, Zhang S, Qian X, Liu F. Roles of Fibroblast Growth Factors in the Axon Guidance. Int J Mol Sci 2023; 24:10292. [PMID: 37373438 DOI: 10.3390/ijms241210292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Fibroblast growth factors (FGFs) have been widely studied by virtue of their ability to regulate many essential cellular activities, including proliferation, survival, migration, differentiation and metabolism. Recently, these molecules have emerged as the key components in forming the intricate connections within the nervous system. FGF and FGF receptor (FGFR) signaling pathways play important roles in axon guidance as axons navigate toward their synaptic targets. This review offers a current account of axonal navigation functions performed by FGFs, which operate as chemoattractants and/or chemorepellents in different circumstances. Meanwhile, detailed mechanisms behind the axon guidance process are elaborated, which are related to intracellular signaling integration and cytoskeleton dynamics.
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Affiliation(s)
- Weiyun Zhang
- Queen Mary School, Medical College, Nanchang University, Nanchang 330000, China
- Medical Experimental Teaching Center, School of Basic Medical Sciences, Nanchang University, Nanchang 330031, China
| | - Peiyi Luo
- Queen Mary School, Medical College, Nanchang University, Nanchang 330000, China
| | - Xiaohan Liu
- Department of General Surgery, Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Ruoxi Cheng
- Queen Mary School, Medical College, Nanchang University, Nanchang 330000, China
| | - Shuxian Zhang
- Queen Mary School, Medical College, Nanchang University, Nanchang 330000, China
| | - Xiao Qian
- Queen Mary School, Medical College, Nanchang University, Nanchang 330000, China
| | - Fang Liu
- Department of Cell Biology, School of Basic Medical Sciences, Nanchang University, Nanchang 330031, China
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5
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Kiral FR, Cakir B, Tanaka Y, Kim J, Yang WS, Wehbe F, Kang YJ, Zhong M, Sancer G, Lee SH, Xiang Y, Park IH. Generation of ventralized human thalamic organoids with thalamic reticular nucleus. Cell Stem Cell 2023; 30:677-688.e5. [PMID: 37019105 PMCID: PMC10329908 DOI: 10.1016/j.stem.2023.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 02/06/2023] [Accepted: 03/09/2023] [Indexed: 04/07/2023]
Abstract
Human brain organoids provide unique platforms for modeling several aspects of human brain development and pathology. However, current brain organoid systems mostly lack the resolution to recapitulate the development of finer brain structures with subregional identity, including functionally distinct nuclei in the thalamus. Here, we report a method for converting human embryonic stem cells (hESCs) into ventral thalamic organoids (vThOs) with transcriptionally diverse nuclei identities. Notably, single-cell RNA sequencing revealed previously unachieved thalamic patterning with a thalamic reticular nucleus (TRN) signature, a GABAergic nucleus located in the ventral thalamus. Using vThOs, we explored the functions of TRN-specific, disease-associated genes patched domain containing 1 (PTCHD1) and receptor tyrosine-protein kinase (ERBB4) during human thalamic development. Perturbations in PTCHD1 or ERBB4 impaired neuronal functions in vThOs, albeit not affecting the overall thalamic lineage development. Together, vThOs present an experimental model for understanding nuclei-specific development and pathology in the thalamus of the human brain.
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Affiliation(s)
- Ferdi Ridvan Kiral
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Bilal Cakir
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Yoshiaki Tanaka
- Department of Medicine, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada
| | - Jonghun Kim
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Woo Sub Yang
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Fabien Wehbe
- Department of Medicine, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada
| | - Young-Jin Kang
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Mei Zhong
- Department of Cell Biology, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Gizem Sancer
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Sang-Hun Lee
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Yangfei Xiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - In-Hyun Park
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06520, USA.
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6
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Huerga-Gómez I, Martini FJ, López-Bendito G. Building thalamic neuronal networks during mouse development. Front Neural Circuits 2023; 17:1098913. [PMID: 36817644 PMCID: PMC9936079 DOI: 10.3389/fncir.2023.1098913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
The thalamic nuclear complex contains excitatory projection neurons and inhibitory local neurons, the two cell types driving the main circuits in sensory nuclei. While excitatory neurons are born from progenitors that reside in the proliferative zone of the developing thalamus, inhibitory local neurons are born outside the thalamus and they migrate there during development. In addition to these cell types, which occupy most of the thalamus, there are two small thalamic regions where inhibitory neurons target extra-thalamic regions rather than neighboring neurons, the intergeniculate leaflet and the parahabenular nucleus. Like excitatory thalamic neurons, these inhibitory neurons are derived from progenitors residing in the developing thalamus. The assembly of these circuits follows fine-tuned genetic programs and it is coordinated by extrinsic factors that help the cells find their location, associate with thalamic partners, and establish connections with their corresponding extra-thalamic inputs and outputs. In this review, we bring together what is currently known about the development of the excitatory and inhibitory components of the thalamocortical sensory system, in particular focusing on the visual pathway and thalamic interneurons in mice.
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Affiliation(s)
- Irene Huerga-Gómez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, Spain
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7
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Douceau S, Deutsch Guerrero T, Ferent J. Establishing Hedgehog Gradients during Neural Development. Cells 2023; 12:cells12020225. [PMID: 36672161 PMCID: PMC9856818 DOI: 10.3390/cells12020225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/23/2022] [Accepted: 12/25/2022] [Indexed: 01/07/2023] Open
Abstract
A morphogen is a signaling molecule that induces specific cellular responses depending on its local concentration. The concept of morphogenic gradients has been a central paradigm of developmental biology for decades. Sonic Hedgehog (Shh) is one of the most important morphogens that displays pleiotropic functions during embryonic development, ranging from neuronal patterning to axon guidance. It is commonly accepted that Shh is distributed in a gradient in several tissues from different origins during development; however, how these gradients are formed and maintained at the cellular and molecular levels is still the center of a great deal of research. In this review, we first explored all of the different sources of Shh during the development of the nervous system. Then, we detailed how these sources can distribute Shh in the surrounding tissues via a variety of mechanisms. Finally, we addressed how disrupting Shh distribution and gradients can induce severe neurodevelopmental disorders and cancers. Although the concept of gradient has been central in the field of neurodevelopment since the fifties, we also describe how contemporary leading-edge techniques, such as organoids, can revisit this classical model.
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Affiliation(s)
- Sara Douceau
- INSERM UMR-S 1270, F-75005 Paris, France
- Institut du Fer à Moulin, INSERM, Sorbonne Univeristy, F-75005 Paris, France
| | - Tanya Deutsch Guerrero
- INSERM UMR-S 1270, F-75005 Paris, France
- Institut du Fer à Moulin, INSERM, Sorbonne Univeristy, F-75005 Paris, France
| | - Julien Ferent
- INSERM UMR-S 1270, F-75005 Paris, France
- Institut du Fer à Moulin, INSERM, Sorbonne Univeristy, F-75005 Paris, France
- Correspondence:
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8
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Alzu'bi A, Sankar N, Crosier M, Kerwin J, Clowry GJ. Tyramide signal amplification coupled with multiple immunolabeling and RNAScope in situ hybridization in formaldehyde-fixed paraffin-embedded human fetal brain. J Anat 2022; 241:33-41. [PMID: 35224745 PMCID: PMC9178390 DOI: 10.1111/joa.13644] [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: 12/03/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/28/2022] Open
Abstract
Several strategies have been recently introduced to improve the practicality of multiple immunolabeling and RNA in situ hybridization protocols. Tyramide signal amplification (TSA) is a powerful method used to improve the detection sensitivity of immunohistochemistry. RNAScope is a novel commercially available in situ hybridization assay for the detection of RNA expression. In this work, we describe the use of TSA and RNAScope in situ hybridization as extremely sensitive and specific methods for the evaluation of protein and RNA expression in formaldehyde-fixed paraffin-embedded human fetal brain sections. These two techniques, when properly optimized, were highly compatible with routine formaldehyde-fixed paraffin-embedded tissue that preserves the best morphological characteristics of delicate fetal brain samples, enabling an unparalleled ability to simultaneously visualize the expression of multiple protein and mRNA of genes that are sparsely expressed in the human fetal telencephalon.
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Affiliation(s)
- Ayman Alzu'bi
- Biosciences InstituteNewcastle UniversityNewcastle upon TyneUK
- Department of Basic Medical SciencesYarmouk UniversityIrbidJordan
| | - Niveditha Sankar
- Biosciences InstituteNewcastle UniversityNewcastle upon TyneUK
- Present address:
Department of Biomedical Sciences, School of MedicineUniversity of North DakotaGrand ForksNorth DakotaUSA
| | - Moira Crosier
- Biosciences InstituteNewcastle UniversityNewcastle upon TyneUK
- Human Developmental Biology ResourceNewcastle UniversityNewcastle upon TyneUK
| | - Janet Kerwin
- Biosciences InstituteNewcastle UniversityNewcastle upon TyneUK
- Human Developmental Biology ResourceNewcastle UniversityNewcastle upon TyneUK
| | - Gavin J. Clowry
- Biosciences InstituteNewcastle UniversityNewcastle upon TyneUK
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9
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Leung RF, George AM, Roussel EM, Faux MC, Wigle JT, Eisenstat DD. Genetic Regulation of Vertebrate Forebrain Development by Homeobox Genes. Front Neurosci 2022; 16:843794. [PMID: 35546872 PMCID: PMC9081933 DOI: 10.3389/fnins.2022.843794] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/14/2022] [Indexed: 01/19/2023] Open
Abstract
Forebrain development in vertebrates is regulated by transcription factors encoded by homeobox, bHLH and forkhead gene families throughout the progressive and overlapping stages of neural induction and patterning, regional specification and generation of neurons and glia from central nervous system (CNS) progenitor cells. Moreover, cell fate decisions, differentiation and migration of these committed CNS progenitors are controlled by the gene regulatory networks that are regulated by various homeodomain-containing transcription factors, including but not limited to those of the Pax (paired), Nkx, Otx (orthodenticle), Gsx/Gsh (genetic screened), and Dlx (distal-less) homeobox gene families. This comprehensive review outlines the integral role of key homeobox transcription factors and their target genes on forebrain development, focused primarily on the telencephalon. Furthermore, links of these transcription factors to human diseases, such as neurodevelopmental disorders and brain tumors are provided.
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Affiliation(s)
- Ryan F. Leung
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Ankita M. George
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Enola M. Roussel
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Maree C. Faux
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Jeffrey T. Wigle
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - David D. Eisenstat
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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10
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Callejas-Marin A, Moreno-Bravo JA, Company V, Madrigal MP, Almagro-García F, Martínez S, Puelles E. Gli2-Mediated Shh Signaling Is Required for Thalamocortical Projection Guidance. Front Neuroanat 2022; 16:830758. [PMID: 35221935 PMCID: PMC8866834 DOI: 10.3389/fnana.2022.830758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/13/2022] [Indexed: 11/13/2022] Open
Abstract
The thalamocortical projections are part of the most important higher level processing connections in the vertebrates and follow a highly ordered pathway from their origin in the thalamus to the cerebral cortex. Their functional complexities are not only due to an extremely elaborate axon guidance process but also due to activity-dependent mechanisms. Gli2 is an intermediary transcription factor in the Sonic hedgehog (Shh) pathway. During neural early development, Shh has an important role in dorsoventral patterning, diencephalic anteroposterior patterning, and many later developmental processes, such as axon guidance and cell migration. Using a Gli2 knockout mouse line, we have studied the role of Shh signaling mediated by Gli2 in the development of the thalamocortical projections during embryonic development. In wild-type brains, we have described the normal trajectory of the thalamocortical axons into the context of the prosomeric model. Then, we have compared it with the altered thalamocortical axons course in Gli2 homozygous embryos. The thalamocortical axons followed different trajectories and were misdirected to other territories probably due to alterations in the Robo/Slit signaling mechanism. In conclusion, the alteration of Gli2-mediated Shh signaling produces an erroneous specification of several territories related with the thalamocortical axons. This is translated into a huge modification in the pathfinding signaling mechanisms needed for the correct wiring of the thalamocortical axons.
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Affiliation(s)
- Antuca Callejas-Marin
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Juan Antonio Moreno-Bravo
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Verónica Company
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
| | - M. Pilar Madrigal
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Francisca Almagro-García
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Salvador Martínez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Eduardo Puelles
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, Elche, Spain
- *Correspondence: Eduardo Puelles,
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11
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Composite morphogenesis during embryo development. Semin Cell Dev Biol 2021; 120:119-132. [PMID: 34172395 DOI: 10.1016/j.semcdb.2021.06.007] [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: 03/24/2021] [Revised: 05/23/2021] [Accepted: 06/13/2021] [Indexed: 11/21/2022]
Abstract
Morphogenesis drives the formation of functional living shapes. Gene expression patterns and signaling pathways define the body plans of the animal and control the morphogenetic processes shaping the embryonic tissues. During embryogenesis, a tissue can undergo composite morphogenesis resulting from multiple concomitant shape changes. While previous studies have unraveled the mechanisms that drive simple morphogenetic processes, how a tissue can undergo multiple and simultaneous changes in shape is still not known and not much explored. In this chapter, we focus on the process of concomitant tissue folding and extension that is vital for the animal since it is key for embryo gastrulation and neurulation. Recent pioneering studies focus on this problem highlighting the roles of different spatially coordinated cell mechanisms or of the synergy between different patterns of gene expression to drive composite morphogenesis.
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12
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Jung J, Kim J, Huh TL, Rhee M. Trim46 contributes to the midbrain development via Sonic Hedgehog signaling pathway in zebrafish embryos. Anim Cells Syst (Seoul) 2021; 25:56-64. [PMID: 33717417 PMCID: PMC7935121 DOI: 10.1080/19768354.2021.1889661] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
TRIM46 is a RING finger E3 ligase which belongs to TRIM (tripartite motif-containing) protein family. TRIM46 is required for neuronal polarity and axon specification by driving the formation of parallel microtubule arrays, whereas its embryological functions remain to be determined yet. Expression patterns and biological functions of trim46a, a zebrafish homologue of TRIM46, were studied in zebrafish embryo. First, maternal transcripts of trim46a were present at 1 cell stage whereas zygotic messages were abundant in the eyes, MHB (Midbrain-Hindbrain Boundary) and hindbrain at 24 hpf (hours post fertilization). Second, transcriptional regulatory region of trim46a contains cis-acting elements binding a transcriptional factor Foxa2. Transcription of foxa2 is positively regulated by Sonic Hedgehog (SHH), and treatment of cyclopamine, an SHH inhibitor, represses transcription of foxa2 in 4 hpf through 24 hpf embryos. Third, the transcriptional repression of foxa2 inhibited transcription of trim46a to cause developmental defects in the midbrain and MHB. Finally, spatiotemporal expression patterns of a midbrain marker otx2b in the developmental defects confirmed inhibition of SHH by cyclopamine caused underdevelopment of the midbrain and MHB at 24 hpf. We propose a signaling network where trim46a contributes to development of the midbrain and MHB via Foxa2, a downstream element of SHH signaling in zebrafish embryogenesis.
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Affiliation(s)
- Jangham Jung
- Department of Life Science, BK21 Plus Program, Graduate School, Daejeon, South Korea
| | - Jaehun Kim
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, South Korea
| | - Tae-Lin Huh
- School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea
| | - Myungchull Rhee
- Department of Life Science, BK21 Plus Program, Graduate School, Daejeon, South Korea.,Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, South Korea
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13
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Puelles L, Diaz C, Stühmer T, Ferran JL, Martínez‐de la Torre M, Rubenstein JLR. LacZ-reporter mapping of Dlx5/6 expression and genoarchitectural analysis of the postnatal mouse prethalamus. J Comp Neurol 2021; 529:367-420. [PMID: 32420617 PMCID: PMC7671952 DOI: 10.1002/cne.24952] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 12/22/2022]
Abstract
We present here a thorough and complete analysis of mouse P0-P140 prethalamic histogenetic subdivisions and corresponding nuclear derivatives, in the context of local tract landmarks. The study used as fundamental material brains from a transgenic mouse line that expresses LacZ under the control of an intragenic enhancer of Dlx5 and Dlx6 (Dlx5/6-LacZ). Subtle shadings of LacZ signal, jointly with pan-DLX immunoreaction, and several other ancillary protein or RNA markers, including Calb2 and Nkx2.2 ISH (for the prethalamic eminence, and derivatives of the rostral zona limitans shell domain, respectively) were mapped across the prethalamus. The resulting model of the prethalamic region postulates tetrapartite rostrocaudal and dorsoventral subdivisions, as well as a tripartite radial stratification, each cell population showing a characteristic molecular profile. Some novel nuclei are proposed, and some instances of potential tangential cell migration were noted.
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Affiliation(s)
- Luis Puelles
- Department of Human Anatomy and Psychobiology and IMIB‐Arrixaca InstituteUniversity of MurciaMurciaSpain
| | - Carmen Diaz
- Department of Medical Sciences, School of Medicine and Institute for Research in Neurological DisabilitiesUniversity of Castilla‐La ManchaAlbaceteSpain
| | - Thorsten Stühmer
- Nina Ireland Laboratory of Developmental Neurobiology, Department of PsychiatryUCSF Medical SchoolSan FranciscoCaliforniaUSA
| | - José L. Ferran
- Department of Human Anatomy and Psychobiology and IMIB‐Arrixaca InstituteUniversity of MurciaMurciaSpain
| | | | - John L. R. Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, Department of PsychiatryUCSF Medical SchoolSan FranciscoCaliforniaUSA
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14
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Ball G, Seidlitz J, O’Muircheartaigh J, Dimitrova R, Fenchel D, Makropoulos A, Christiaens D, Schuh A, Passerat-Palmbach J, Hutter J, Cordero-Grande L, Hughes E, Price A, Hajnal JV, Rueckert D, Robinson EC, Edwards AD. Cortical morphology at birth reflects spatiotemporal patterns of gene expression in the fetal human brain. PLoS Biol 2020; 18:e3000976. [PMID: 33226978 PMCID: PMC7721147 DOI: 10.1371/journal.pbio.3000976] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 12/07/2020] [Accepted: 11/02/2020] [Indexed: 02/07/2023] Open
Abstract
Interruption to gestation through preterm birth can significantly impact cortical development and have long-lasting adverse effects on neurodevelopmental outcome. We compared cortical morphology captured by high-resolution, multimodal magnetic resonance imaging (MRI) in n = 292 healthy newborn infants (mean age at birth = 39.9 weeks) with regional patterns of gene expression in the fetal cortex across gestation (n = 156 samples from 16 brains, aged 12 to 37 postconceptional weeks [pcw]). We tested the hypothesis that noninvasive measures of cortical structure at birth mirror areal differences in cortical gene expression across gestation, and in a cohort of n = 64 preterm infants (mean age at birth = 32.0 weeks), we tested whether cortical alterations observed after preterm birth were associated with altered gene expression in specific developmental cell populations. Neonatal cortical structure was aligned to differential patterns of cell-specific gene expression in the fetal cortex. Principal component analysis (PCA) of 6 measures of cortical morphology and microstructure showed that cortical regions were ordered along a principal axis, with primary cortex clearly separated from heteromodal cortex. This axis was correlated with estimated tissue maturity, indexed by differential expression of genes expressed by progenitor cells and neurons, and engaged in stem cell differentiation, neuron migration, and forebrain development. Preterm birth was associated with altered regional MRI metrics and patterns of differential gene expression in glial cell populations. The spatial patterning of gene expression in the developing cortex was thus mirrored by regional variation in cortical morphology and microstructure at term, and this was disrupted by preterm birth. This work provides a framework to link molecular mechanisms to noninvasive measures of cortical development in early life and highlights novel pathways to injury in neonatal populations at increased risk of neurodevelopmental disorder. Interruption to gestation through preterm birth can significantly impact cortical development and have long-lasting adverse effects on neurodevelopmental outcome. A large neuroimaging study of newborn infants reveals how their cortical structure at birth is associated with patterns of gene expression in the fetal cortex and how this relationship is affected by preterm birth.
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Affiliation(s)
- Gareth Ball
- Developmental Imaging, Murdoch Children’s Research Institute, Melbourne, Australia
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
- * E-mail:
| | - Jakob Seidlitz
- Developmental Neurogenomics Unit, National Institute of Mental Health, Bethesda, United States of America
- Department of Psychiatry, University of Cambridge, United Kingdom
| | - Jonathan O’Muircheartaigh
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Ralica Dimitrova
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Daphna Fenchel
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Antonios Makropoulos
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Daan Christiaens
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
- Department of Electrical Engineering, ESAT/PSI, KU Leuven, Belgium
| | - Andreas Schuh
- Biomedical Image Analysis Group, Department of Computing, Imperial College London, United Kingdom
| | | | - Jana Hutter
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Lucilio Cordero-Grande
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Emer Hughes
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Anthony Price
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Jo V. Hajnal
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - Daniel Rueckert
- Biomedical Image Analysis Group, Department of Computing, Imperial College London, United Kingdom
| | - Emma C. Robinson
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
| | - A David Edwards
- Centre for the Developing Brain, Department of Perinatal Imaging & Health, King’s College London, United Kingdom
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15
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Morona R, Bandín S, López JM, Moreno N, González A. Amphibian thalamic nuclear organization during larval development and in the adult frog Xenopus laevis: Genoarchitecture and hodological analysis. J Comp Neurol 2020; 528:2361-2403. [PMID: 32162311 DOI: 10.1002/cne.24899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 12/18/2022]
Abstract
The early patterning of the thalamus during embryonic development defines rostral and caudal progenitor domains, which are conserved from fishes to mammals. However, the subsequent developmental mechanisms that lead to the adult thalamic configuration have only been investigated for mammals and other amniotes. In this study, we have analyzed in the anuran amphibian Xenopus laevis (an anamniote vertebrate), through larval and postmetamorphic development, the progressive regional expression of specific markers for the rostral (GABA, GAD67, Lhx1, and Nkx2.2) and caudal (Gbx2, VGlut2, Lhx2, Lhx9, and Sox2) domains. In addition, the regional distributions at different developmental stages of other markers such as calcium binding proteins and neuropeptides, helped the identification of thalamic nuclei. It was observed that the two embryonic domains were progressively specified and compartmentalized during premetamorphosis, and cell subpopulations characterized by particular gene expression combinations were located in periventricular, intermediate and superficial strata. During prometamorphosis, three dorsoventral tiers formed from the caudal domain and most pronuclei were defined, which were modified into the definitive nuclear configuration through the metamorphic climax. Mixed cell populations originated from the rostral and caudal domains constitute most of the final nuclei and allowed us to propose additional subdivisions in the adult thalamus, whose main afferent and efferent connections were assessed by tracing techniques under in vitro conditions. This study corroborates shared features of early gene expression patterns in the thalamus between Xenopus and mouse, however, the dynamic changes in gene expression observed at later stages in the amphibian support mechanisms different from those of mammals.
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Affiliation(s)
- Ruth Morona
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
| | - Sandra Bandín
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
| | - Jesús M López
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
| | - Nerea Moreno
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
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16
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Nakagawa Y. Development of the thalamus: From early patterning to regulation of cortical functions. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2019; 8:e345. [PMID: 31034163 DOI: 10.1002/wdev.345] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/28/2019] [Accepted: 04/01/2019] [Indexed: 02/06/2023]
Abstract
The thalamus is a brain structure of the vertebrate diencephalon that plays a central role in regulating diverse functions of the cerebral cortex. In traditional view of vertebrate neuroanatomy, the thalamus includes three regions, dorsal thalamus, ventral thalamus, and epithalamus. Recent molecular embryological studies have redefined the thalamus and the associated axial nomenclature of the diencephalon in the context of forebrain patterning. This new view has provided a useful conceptual framework for studies on molecular mechanisms of patterning, neurogenesis and fate specification in the thalamus as well as the guidance mechanisms for thalamocortical axons. Additionally, the availability of genetic tools in mice has led to important findings on how thalamic development is linked to the development of other brain regions, particularly the cerebral cortex. This article will give an overview of the organization of the embryonic thalamus and how progenitor cells in the thalamus generate neurons that are organized into discrete nuclei. I will then discuss how thalamic development is orchestrated with the development of the cerebral cortex and other brain regions. This article is categorized under: Nervous System Development > Vertebrates: Regional Development Nervous System Development > Vertebrates: General Principles.
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Affiliation(s)
- Yasushi Nakagawa
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota
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17
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Guo Q, Li JYH. Defining developmental diversification of diencephalon neurons through single cell gene expression profiling. Development 2019; 146:dev.174284. [PMID: 30872278 DOI: 10.1242/dev.174284] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/07/2019] [Indexed: 12/31/2022]
Abstract
The embryonic diencephalon forms integration centers and relay stations in the forebrain. Anecdotal expression studies suggest that the diencephalon contains multiple developmental compartments and subdivisions. Here, we utilized single cell RNA sequencing to profile transcriptomes of dissociated cells from the diencephalon of E12.5 mouse embryos. We identified the divergence of different progenitors, intermediate progenitors, and emerging neurons. By mapping the identified cell groups to their spatial origins, we characterized the molecular features of cell types and cell states arising from various diencephalic domains. Furthermore, we reconstructed the developmental trajectory of distinct cell lineages, and thereby identified the genetic cascades and gene regulatory networks underlying the progression of the cell cycle, neurogenesis and cellular diversification. The analysis provides new insights into the molecular mechanisms underlying the amplification of intermediate progenitor cells in the thalamus. The single cell-resolved trajectories not only confirm a close relationship between the rostral thalamus and prethalamus, but also uncover an unexpected close relationship between the caudal thalamus, epithalamus and rostral pretectum. Our data provide a useful resource for systematic studies of cell heterogeneity and differentiation kinetics within the diencephalon.
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Affiliation(s)
- Qiuxia Guo
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, CT 06030-6403, USA
| | - James Y H Li
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, CT 06030-6403, USA .,Institute for Systems Genomics, University of Connecticut, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
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18
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The Ciliopathy Gene Ftm/Rpgrip1l Controls Mouse Forebrain Patterning via Region-Specific Modulation of Hedgehog/Gli Signaling. J Neurosci 2019; 39:2398-2415. [PMID: 30692221 PMCID: PMC6435827 DOI: 10.1523/jneurosci.2199-18.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/22/2018] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Primary cilia are essential for CNS development. In the mouse, they play a critical role in patterning the spinal cord and telencephalon via the regulation of Hedgehog/Gli signaling. However, despite the frequent disruption of this signaling pathway in human forebrain malformations, the role of primary cilia in forebrain morphogenesis has been little investigated outside the telencephalon. Here we studied development of the diencephalon, hypothalamus and eyes in mutant mice in which the Ftm/Rpgrip1l ciliopathy gene is disrupted. At the end of gestation, Ftm−/− fetuses displayed anophthalmia, a reduction of the ventral hypothalamus and a disorganization of diencephalic nuclei and axonal tracts. In Ftm−/− embryos, we found that the ventral forebrain structures and the rostral thalamus were missing. Optic vesicles formed but lacked the optic cups. In Ftm−/− embryos, Sonic hedgehog (Shh) expression was virtually lost in the ventral forebrain but maintained in the zona limitans intrathalamica (ZLI), the mid-diencephalic organizer. Gli activity was severely downregulated but not lost in the ventral forebrain and in regions adjacent to the Shh-expressing ZLI. Reintroduction of the repressor form of Gli3 into the Ftm−/− background restored optic cup formation. Our data thus uncover a complex role of cilia in development of the diencephalon, hypothalamus and eyes via the region-specific control of the ratio of activator and repressor forms of the Gli transcription factors. They call for a closer examination of forebrain defects in severe ciliopathies and for a search for ciliopathy genes as modifiers in other human conditions with forebrain defects. SIGNIFICANCE STATEMENT The Hedgehog (Hh) signaling pathway is essential for proper forebrain development as illustrated by a human condition called holoprosencephaly. The Hh pathway relies on primary cilia, cellular organelles that receive and transduce extracellular signals and whose dysfunctions lead to rare inherited diseases called ciliopathies. To date, the role of cilia in the forebrain has been poorly studied outside the telencephalon. In this paper we study the role of the Ftm/Rpgrip1l ciliopathy gene in mouse forebrain development. We uncover complex functions of primary cilia in forebrain morphogenesis through region-specific modulation of the Hh pathway. Our data call for further examination of forebrain defects in ciliopathies and for a search for ciliopathy genes as modifiers in human conditions affecting forebrain development.
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19
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Minor PJ, Clarke DN, Andrade López JM, Fritzenwanker JH, Gray J, Lowe CJ. I-SceI Meganuclease-mediated transgenesis in the acorn worm, Saccoglossus kowalevskii. Dev Biol 2019; 445:8-15. [PMID: 30412702 PMCID: PMC6327965 DOI: 10.1016/j.ydbio.2018.10.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 11/17/2022]
Abstract
Hemichordates are a phylum of marine invertebrate deuterostomes that are closely related to chordates, and represent one of the most promising models to provide insights into early deuterostome evolution. The genome of the hemichordate, Saccoglossus kowalevskii, reveals an extensive set of non-coding elements conserved across all three deuterostome phyla. Functional characterization and cross-phyla comparisons of these putative regulatory elements will enable a better understanding of enhancer evolution, and subsequently how changes in gene regulation give rise to morphological innovation. Here, we describe an efficient method of transgenesis for the characterization of non-coding elements in S. kowalevskii. We first test the capacity of an I-SceI transgenesis system to drive ubiquitous or regionalized gene expression, and to label specific cell types. Finally, we identified a minimal promoter that can be used to test the capacity of putative enhancers in S. kowalevskii. This work demonstrates that this I-SceI transgenesis technique, when coupled with an understanding of chromatin accessibility, can be a powerful tool for studying how evolutionary changes in gene regulatory mechanisms contributed to the diversification of body plans in deuterostomes.
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Affiliation(s)
- Paul J Minor
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, United States.
| | - D Nathaniel Clarke
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, United States
| | - José M Andrade López
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, United States
| | - Jens H Fritzenwanker
- Department of Biology, Georgetown University, 411 Regents Hall, 37th and O Streets, NW, Washington DC 20057, United States
| | - Jessica Gray
- Department of Systems Biology, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115, United States
| | - Christopher J Lowe
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, United States.
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20
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Nadadhur AG, Leferink PS, Holmes D, Hinz L, Cornelissen-Steijger P, Gasparotto L, Heine VM. Patterning factors during neural progenitor induction determine regional identity and differentiation potential in vitro. Stem Cell Res 2018; 32:25-34. [PMID: 30172094 DOI: 10.1016/j.scr.2018.08.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 08/13/2018] [Accepted: 08/22/2018] [Indexed: 12/20/2022] Open
Abstract
The neural tube consists of neural progenitors (NPs) that acquire different characteristics during gestation due to patterning factors. However, the influence of such patterning factors on human pluripotent stem cells (hPSCs) during in vitro neural differentiation is often unclear. This study compared neural induction protocols involving in vitro patterning with single SMAD inhibition (SSI), retinoic acid (RA) administration and dual SMAD inhibition (DSI). While the derived NP cells expressed known NP markers, they differed in their NP expression profile and differentiation potential. Cortical neuronal cells generated from 1) SSI NPs exhibited less mature neuronal phenotypes, 2) RA NPs exhibited an increased GABAergic phenotype, and 3) DSI NPs exhibited greater expression of glutamatergic lineage markers. Further, although all NPs generated astrocytes, astrocytes derived from the RA-induced NPs had the highest GFAP expression. Differences between NP populations included differential expression of regional identity markers HOXB4, LBX1, OTX1 and GSX2, which persisted into mature neural cell stages. This study suggests that patterning factors regulate how potential NPs may differentiate into specific neuronal and glial cell types in vitro. This challenges the utility of generic neural induction procedures, while highlighting the importance of carefully selecting specific NP protocols.
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Affiliation(s)
- Aishwarya G Nadadhur
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands
| | - Prisca S Leferink
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands
| | - Dwayne Holmes
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands
| | - Lisa Hinz
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands
| | - Paulien Cornelissen-Steijger
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands
| | - Lisa Gasparotto
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands
| | - Vivi M Heine
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands; Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, the Netherlands.
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21
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Newman EA, Wu D, Taketo MM, Zhang J, Blackshaw S. Canonical Wnt signaling regulates patterning, differentiation and nucleogenesis in mouse hypothalamus and prethalamus. Dev Biol 2018; 442:236-248. [PMID: 30063881 DOI: 10.1016/j.ydbio.2018.07.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/26/2018] [Accepted: 07/26/2018] [Indexed: 01/10/2023]
Abstract
The hypothalamus is a small, but anatomically and functionally complex region of the brain whose development is poorly understood. In this study, we have explored its development by studying the canonical Wnt signaling pathway, generating gain and loss of function mutations of beta-catenin (Ctnnb1) in both hypothalamic and prethalamic neuroepithelium. Deletion of Ctnnb1 resulted in an anteriorized and hypoplastic hypothalamus. Posterior structures were lost or reduced, and anterior structures were expanded. In contrast, overexpression of a constitutively active mutant form of Ctnnb1 resulted in severe hyperplasia of prethalamus and hypothalamus, and expanded expression of a subset of posterior and premamillary hypothalamic markers. Moderate defects in differentiation of Arx-positive GABAergic neural precursors were observed in both prethalamus and hypothalamus of Ctnnb1 loss of function mutants, while in gain of function mutants, their differentiation was completely suppressed, although markers of prethalamic progenitors were preserved. Multiple other region-specific markers, including several specific posterior hypothalamic structures, were also suppressed in Ctnnb1 gain of function mutations. Severe, region-specific defects in hypothalamic nucleogenesis were also observed in both gain and loss of function mutations of Ctnnb1. Finally, both gain and loss of function of Ctnnb1 also produced severe, non-cell autonomous disruptions of pituitary development. These findings demonstrate a central and multifaceted role for canonical Wnt signaling in regulating growth, patterning, differentiation and nucleogenesis in multiple diencephalic regions.
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Affiliation(s)
- Elizabeth A Newman
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dan Wu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Makoto Mark Taketo
- Division of Experimental Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Jiangyang Zhang
- Department of Radiology, NYU Langone School of Medicine, New York, NY, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Center for Human Systems Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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22
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Liu B, Zhou K, Wu X, Zhao C. Foxg1 deletion impairs the development of the epithalamus. Mol Brain 2018; 11:5. [PMID: 29394901 PMCID: PMC5797387 DOI: 10.1186/s13041-018-0350-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/24/2018] [Indexed: 12/14/2022] Open
Abstract
The epithalamus, which is dorsal to the thalamus, consists of the habenula, pineal gland and third ventricle choroid plexus and plays important roles in the stress response and sleep-wake cycle in vertebrates. During development, the epithalamus arises from the most dorsal part of prosomere 2. However, the mechanism underlying epithalamic development remains largely unknown. Foxg1 is critical for the development of the telencephalon, but its role in diencephalic development has been under-investigated. Patients suffering from FOXG1-related disorders exhibit severe anxiety, sleep disturbance and choroid plexus cysts, indicating that Foxg1 likely plays a role in epithalamic development. In this study, we identified the specific expression of Foxg1 in the developing epithalamus. Using a "self-deletion" approach, we found that the habenula significantly expanded and included an increased number of habenular subtype neurons. The innervations, particularly the habenular commissure, were severely impaired. Meanwhile, the Foxg1 mutants exhibited a reduced pineal gland and more branched choroid plexus. After ablation of Foxg1 no obvious changes in Shh and Fgf signalling were observed, suggesting that Foxg1 regulates the development of the epithalamus without the involvement of Shh and Fgfs. Our findings provide new insights into the regulation of the development of the epithalamus.
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Affiliation(s)
- Bin Liu
- Key Laboratory of Developmental Genes and Human Diseases, MOE, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Kaixing Zhou
- Key Laboratory of Developmental Genes and Human Diseases, MOE, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Xiaojing Wu
- Key Laboratory of Developmental Genes and Human Diseases, MOE, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, MOE, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China. .,Depression Center, Institute for Brain Disorders, Beijing, 100069, China.
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23
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Lee B, Lee M, Song S, Loi LD, Lam DT, Yoon J, Baek K, Curtis DJ, Jeong Y. Specification of neurotransmitter identity by Tal1 in thalamic nuclei. Dev Dyn 2017; 246:749-758. [PMID: 28685891 DOI: 10.1002/dvdy.24546] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/20/2017] [Accepted: 07/04/2017] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The neurons contributing to thalamic nuclei are derived from at least two distinct progenitor domains: the caudal (cTH) and rostral (rTH) populations of thalamic progenitors. These neural compartments exhibit unique neurogenic patterns, and the molecular mechanisms underlying the acquisition of neurotransmitter identity remain largely unclear. RESULTS T-cell acute lymphocytic leukemia protein 1 (Tal1) was expressed in the early postmitotic cells in the rTH domain, and its expression was maintained in mature thalamic neurons in the ventrolateral geniculate nucleus (vLG) and the intergeniculate leaflet (IGL). To investigate a role of Tal1 in thalamic development, we used a newly generated mouse line driving Cre-mediated recombination in the rTH domain. Conditional deletion of Tal1 did not alter regional patterning in the developing diencephalon. However, in the absence of Tal1, rTH-derived thalamic neurons failed to maintain their postmitotic neuronal features, including neurotransmitter profile. Tal1-deficient thalamic neurons lost their GABAergic markers such as Gad1, Npy, and Penk in IGL/vLG. These defects may be associated at least in part with down-regulation of Nkx2.2, which is known as a critical regulator of rTH-derived GABAergic neurons. CONCLUSIONS Our results demonstrate that Tal1 plays an essential role in regulating neurotransmitter phenotype in the developing thalamic nuclei. Developmental Dynamics 246:749-758, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Bumwhee Lee
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - Myungsin Lee
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - Somang Song
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - Linh Duc Loi
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - Duc Tri Lam
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - Jaeseung Yoon
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - Kwanghee Baek
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
| | - David J Curtis
- Australian Centre for Blood Diseases, Central Clinical School, Monash University, Melbourne, Australia
| | - Yongsu Jeong
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea
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24
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Charting the protomap of the human telencephalon. Semin Cell Dev Biol 2017; 76:3-14. [PMID: 28834762 DOI: 10.1016/j.semcdb.2017.08.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/15/2017] [Indexed: 12/16/2022]
Abstract
The cerebral cortex is divided stereotypically into a number of functionally distinct areas. According to the protomap hypothesis formulated by Rakic neural progenitors in the ventricular zone form a mosaic of proliferative units that provide a primordial species-specific cortical map. Positional information of newborn neurons is maintained during their migration to the overlying cortical plate. Much evidence has been found to support this hypothesis from studies of primary cortical areas in mouse models in particular. Differential expansion of cortical areas and the introduction of new functional modules during evolution might be the result of changes in the progenitor cells. The human cerebral cortex shows a wide divergence from the mouse containing a much higher proportion of association cortex and a more complicated regionalised repertoire of neuron sub-types. To what extent does the protomap hypothesis hold true for the primate brain? This review summarises a growing number of studies exploring arealised gene expression in the early developing human telencephalon. The evidence so far is that the human and mouse brain do share fundamental mechanisms of areal specification, however there are subtle differences which could lead us to a better understanding of cortical evolution and the origins of neurodevelopmental diseases.
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Chung WW, Hudziak JJ. The Transitional Age Brain: "The Best of Times and the Worst of Times". Child Adolesc Psychiatr Clin N Am 2017; 26:157-175. [PMID: 28314448 DOI: 10.1016/j.chc.2016.12.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Over the past two decades, there have been substantial developments in the understanding of brain development and the importance of environmental inputs and context. This paper focuses on the neurodevelopmental mismatch that occurs during the epoch we term the 'transitional age brain' (ages 13-25) and the collateral behavioral correlates. We summarize research findings supporting the argument that, because of this neurodevelopmental mismatch, transitional age youth are at high risk for engaging in behaviors that lead to negative outcomes, morbidity, and mortality. We highlight the need to develop new, neuroscience-inspired health promotion and illness prevention approaches for transitional age youth.
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Affiliation(s)
- Winston W Chung
- Vermont Center for Children, Youth, and Family, University of Vermont Medical Center, 1 South Prospect Street, Arnold 3, Burlington, Vermont 05401, USA
| | - James J Hudziak
- University of Vermont College of Medicine and Medical Center, 1 South Prospect Street, Arnold 3, Burlington, Vermont 05401, USA.
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26
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Lee M, Yoon J, Song H, Lee B, Lam DT, Yoon J, Baek K, Clevers H, Jeong Y. Tcf7l2 plays crucial roles in forebrain development through regulation of thalamic and habenular neuron identity and connectivity. Dev Biol 2017; 424:62-76. [DOI: 10.1016/j.ydbio.2017.02.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/16/2017] [Accepted: 02/16/2017] [Indexed: 11/28/2022]
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Albuixech-Crespo B, López-Blanch L, Burguera D, Maeso I, Sánchez-Arrones L, Moreno-Bravo JA, Somorjai I, Pascual-Anaya J, Puelles E, Bovolenta P, Garcia-Fernàndez J, Puelles L, Irimia M, Ferran JL. Molecular regionalization of the developing amphioxus neural tube challenges major partitions of the vertebrate brain. PLoS Biol 2017; 15:e2001573. [PMID: 28422959 PMCID: PMC5396861 DOI: 10.1371/journal.pbio.2001573] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 03/22/2017] [Indexed: 11/25/2022] Open
Abstract
All vertebrate brains develop following a common Bauplan defined by anteroposterior (AP) and dorsoventral (DV) subdivisions, characterized by largely conserved differential expression of gene markers. However, it is still unclear how this Bauplan originated during evolution. We studied the relative expression of 48 genes with key roles in vertebrate neural patterning in a representative amphioxus embryonic stage. Unlike nonchordates, amphioxus develops its central nervous system (CNS) from a neural plate that is homologous to that of vertebrates, allowing direct topological comparisons. The resulting genoarchitectonic model revealed that the amphioxus incipient neural tube is unexpectedly complex, consisting of several AP and DV molecular partitions. Strikingly, comparison with vertebrates indicates that the vertebrate thalamus, pretectum, and midbrain domains jointly correspond to a single amphioxus region, which we termed Di-Mesencephalic primordium (DiMes). This suggests that these domains have a common developmental and evolutionary origin, as supported by functional experiments manipulating secondary organizers in zebrafish and mice.
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Affiliation(s)
- Beatriz Albuixech-Crespo
- Department of Genetics, School of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, Barcelona, Spain
| | - Laura López-Blanch
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Demian Burguera
- Department of Genetics, School of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, Barcelona, Spain
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Ignacio Maeso
- Centro Andaluz de Biología del Desarrollo (CSIC/UPO/JA), Sevilla, Spain
| | - Luisa Sánchez-Arrones
- Centro de Biología Molecular Severo Ochoa CSIC-UAM and CIBERER, ISCIII, Madrid, Spain
| | | | - Ildiko Somorjai
- The Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, Scotland, United Kingdom
- Biomedical Sciences Research Complex, University of St Andrews, Fife, Scotland, United Kingdom
| | | | - Eduardo Puelles
- Instituto de Neurociencias, UMH-CSIC, Campus de San Juan, Sant Joan d'Alacant, Alicante, Spain
| | - Paola Bovolenta
- Centro de Biología Molecular Severo Ochoa CSIC-UAM and CIBERER, ISCIII, Madrid, Spain
| | - Jordi Garcia-Fernàndez
- Department of Genetics, School of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, Barcelona, Spain
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, Murcia, Spain
- Institute of Biomedical Research of Murcia (IMIB), Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain
| | - Manuel Irimia
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - José Luis Ferran
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, Murcia, Spain
- Institute of Biomedical Research of Murcia (IMIB), Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain
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28
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Shiraishi A, Muguruma K, Sasai Y. Generation of thalamic neurons from mouse embryonic stem cells. Development 2017; 144:1211-1220. [PMID: 28219951 DOI: 10.1242/dev.144071] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 02/03/2017] [Indexed: 01/08/2023]
Abstract
The thalamus is a diencephalic structure that plays crucial roles in relaying and modulating sensory and motor information to the neocortex. The thalamus develops in the dorsal part of the neural tube at the level of the caudal forebrain. However, the molecular mechanisms that are essential for thalamic differentiation are still unknown. Here, we have succeeded in generating thalamic neurons from mouse embryonic stem cells (mESCs) by modifying the default method that induces the most-anterior neural type in self-organizing culture. A low concentration of the caudalizing factor insulin and a MAPK/ERK kinase inhibitor enhanced the expression of the caudal forebrain markers Otx2 and Pax6. BMP7 promoted an increase in thalamic precursors such as Tcf7l2+/Gbx2+ and Tcf7l2+/Olig3+ cells. mESC thalamic precursors began to express the glutamate transporter vGlut2 and the axon-specific marker VGF, similar to mature projection neurons. The mESC thalamic neurons extended their axons to cortical layers in both organotypic culture and subcortical transplantation. Thus, we have identified the minimum elements sufficient for in vitro generation of thalamic neurons. These findings expand our knowledge of thalamic development.
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Affiliation(s)
- Atsushi Shiraishi
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan.,Laboratory of Growth Regulation, Institute for Virus Research, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.,Laboratory for Cell Asymmetry, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Keiko Muguruma
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan .,Laboratory for Cell Asymmetry, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Yoshiki Sasai
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
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The Many Hats of Sonic Hedgehog Signaling in Nervous System Development and Disease. J Dev Biol 2016; 4:jdb4040035. [PMID: 29615598 PMCID: PMC5831807 DOI: 10.3390/jdb4040035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/17/2016] [Accepted: 11/29/2016] [Indexed: 02/06/2023] Open
Abstract
Sonic hedgehog (Shh) signaling occurs concurrently with the many processes that constitute nervous system development. Although Shh is mostly known for its proliferative and morphogenic action through its effects on neural stem cells and progenitors, it also contributes to neuronal differentiation, axonal pathfinding and synapse formation and function. To participate in these diverse events, Shh signaling manifests differently depending on the maturational state of the responsive cell, on the other signaling pathways regulating neural cell function and the environmental cues that surround target cells. Shh signaling is particularly dynamic in the nervous system, ranging from canonical transcription-dependent, to non-canonical and localized to axonal growth cones. Here, we review the variety of Shh functions in the developing nervous system and their consequences for neurodevelopmental diseases and neural regeneration, with particular emphasis on the signaling mechanisms underlying Shh action.
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Kiecker C, Graham A, Logan M. Differential Cellular Responses to Hedgehog Signalling in Vertebrates-What is the Role of Competence? J Dev Biol 2016; 4:jdb4040036. [PMID: 29615599 PMCID: PMC5831800 DOI: 10.3390/jdb4040036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 11/24/2016] [Accepted: 12/01/2016] [Indexed: 12/21/2022] Open
Abstract
A surprisingly small number of signalling pathways generate a plethora of cellular responses ranging from the acquisition of multiple cell fates to proliferation, differentiation, morphogenesis and cell death. These diverse responses may be due to the dose-dependent activities of signalling factors, or to intrinsic differences in the response of cells to a given signal—a phenomenon called differential cellular competence. In this review, we focus on temporal and spatial differences in competence for Hedgehog (HH) signalling, a signalling pathway that is reiteratively employed in embryos and adult organisms. We discuss the upstream signals and mechanisms that may establish differential competence for HHs in a range of different tissues. We argue that the changing competence for HH signalling provides a four-dimensional framework for the interpretation of the signal that is essential for the emergence of functional anatomy. A number of diseases—including several types of cancer—are caused by malfunctions of the HH pathway. A better understanding of what provides differential competence for this signal may reveal HH-related disease mechanisms and equip us with more specific tools to manipulate HH signalling in the clinic.
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Affiliation(s)
- Clemens Kiecker
- Department of Developmental Neurobiology, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK.
| | - Anthony Graham
- Department of Developmental Neurobiology, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK.
| | - Malcolm Logan
- Randall Division of Cell & Molecular Biophysics, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK.
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31
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Geng X, Acosta S, Lagutin O, Gil HJ, Oliver G. Six3 dosage mediates the pathogenesis of holoprosencephaly. Development 2016; 143:4462-4473. [PMID: 27770010 PMCID: PMC5201039 DOI: 10.1242/dev.132142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 10/12/2016] [Indexed: 01/06/2023]
Abstract
Holoprosencephaly (HPE) is defined as the incomplete separation of the two cerebral hemispheres. The pathology of HPE is variable and, based on the severity of the defect, HPE is divided into alobar, semilobar, and lobar. Using a novel hypomorphic Six3 allele, we demonstrate in mice that variability in Six3 dosage results in different HPE phenotypes. Furthermore, we show that whereas the semilobar phenotype results from severe downregulation of Shh expression in the rostral diencephalon ventral midline, the alobar phenotype is caused by downregulation of Foxg1 expression in the anterior neural ectoderm. Consistent with these results, in vivo activation of the Shh signaling pathway rescued the semilobar phenotype but not the alobar phenotype. Our findings show that variations in Six3 dosage result in different forms of HPE.
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Affiliation(s)
- Xin Geng
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Sandra Acosta
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA
| | - Oleg Lagutin
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hyea Jin Gil
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA
| | - Guillermo Oliver
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA
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32
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Parish EV, Mason JO, Price DJ. Expression of Barhl2 and its relationship with Pax6 expression in the forebrain of the mouse embryo. BMC Neurosci 2016; 17:76. [PMID: 27887593 PMCID: PMC5124293 DOI: 10.1186/s12868-016-0311-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/16/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The transcription factor Barhl2 is an antiproneural transcription factor with roles in neuronal differentiation. The functions of its homologue in Drosophila development are better understood than its functions in mammalian brain development. Existing evidence suggests that its expression in the embryonic forebrain of the mouse is regional and may complement that of another transcription factor that is important for forebrain development, Pax6. The aim of this study is to provide a more detailed description of the Barhl2 expression pattern in the embryonic forebrain than is currently available, to relate its expression domains to those of Pax6 and to examine the effects of Pax6 loss on Barhl2 expression. RESULTS We found that Barhl2 is expressed in the developing diencephalon from the time of anterior neural tube closure. Its expression initially overlaps that of Pax6 in a central region of the alar diencephalon but over the following days their domains of expression become complementary in most forebrain regions. The exceptions are the thalamus and pretectum, where countergradients of Pax6 and Barhl2 expression are established by embryonic day 12.5, before overall Pax6 levels in these regions decline greatly while Barhl2 levels remain relatively high. We found that Barhl2 expression becomes upregulated in specifically the thalamus and pretectum in Pax6-null mice. CONCLUSIONS The region-specific expression pattern of Barhl2 makes it likely to be an important player in the development of region-specific differences in embryonic mouse forebrain. Repression of its expression in the thalamus and pretectum by Pax6 may be crucial for allowing proneural factors to promote normal neuronal differentiation in this region.
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Affiliation(s)
- Elisa V Parish
- Centre for Integrative Physiology, The University of Edinburgh, Hugh Robson Building, Edinburgh, EH8 9XD, UK
| | - John O Mason
- Centre for Integrative Physiology, The University of Edinburgh, Hugh Robson Building, Edinburgh, EH8 9XD, UK
| | - David J Price
- Centre for Integrative Physiology, The University of Edinburgh, Hugh Robson Building, Edinburgh, EH8 9XD, UK.
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33
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Gezelius H, López-Bendito G. Thalamic neuronal specification and early circuit formation. Dev Neurobiol 2016; 77:830-843. [PMID: 27739248 DOI: 10.1002/dneu.22460] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/16/2016] [Accepted: 10/10/2016] [Indexed: 12/12/2022]
Abstract
The thalamus is a central structure of the brain, primarily recognized for the relay of incoming sensory and motor information to the cerebral cortex but also key in high order intracortical communication. It consists of glutamatergic projection neurons organized in several distinct nuclei, each having a stereotype connectivity pattern and functional roles. In the adult, these nuclei can be appreciated by architectural boundaries, although their developmental origin and specification is only recently beginning to be revealed. Here, we summarize the current knowledge on the specification of the distinct thalamic neurons and nuclei, starting from early embryonic patterning until the postnatal days when active sensory experience is initiated and the overall system connectivity is already established. We also include an overview of the guidance processes important for establishing thalamocortical connections, with emphasis on the early topographical specification. The extensively studied thalamocortical axon branching in the cortex is briefly mentioned; however, the maturation and plasticity of this connection are beyond the scope of this review. In separate chapters, additional mechanisms and/or features that influence the specification and development of thalamic neurons and their circuits are also discussed. Finally, an outlook of future directions is given. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 830-843, 2017.
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Affiliation(s)
- Henrik Gezelius
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Avenida Ramón y Cajal, s/n, Sant Joan d'Alacant, Spain
| | - Guillermina López-Bendito
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Avenida Ramón y Cajal, s/n, Sant Joan d'Alacant, Spain
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34
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Chew LJ, DeBoy CA. Pharmacological approaches to intervention in hypomyelinating and demyelinating white matter pathology. Neuropharmacology 2016; 110:605-625. [PMID: 26116759 PMCID: PMC4690794 DOI: 10.1016/j.neuropharm.2015.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 06/10/2015] [Accepted: 06/17/2015] [Indexed: 12/17/2022]
Abstract
White matter disease afflicts both developing and mature central nervous systems. Both cell intrinsic and extrinsic dysregulation result in profound changes in cell survival, axonal metabolism and functional performance. Experimental models of developmental white matter (WM) injury and demyelination have not only delineated mechanisms of signaling and inflammation, but have also paved the way for the discovery of pharmacological approaches to intervention. These reagents have been shown to enhance protection of the mature oligodendrocyte cell, accelerate progenitor cell recruitment and/or differentiation, or attenuate pathological stimuli arising from the inflammatory response to injury. Here we highlight reports of studies in the CNS in which compounds, namely peptides, hormones, and small molecule agonists/antagonists, have been used in experimental animal models of demyelination and neonatal brain injury that affect aspects of excitotoxicity, oligodendrocyte development and survival, and progenitor cell function, and which have been demonstrated to attenuate damage and improve WM protection in experimental models of injury. The molecular targets of these agents include growth factor and neurotransmitter receptors, morphogens and their signaling components, nuclear receptors, as well as the processes of iron transport and actin binding. By surveying the current evidence in non-immune targets of both the immature and mature WM, we aim to better understand pharmacological approaches modulating endogenous oligodendroglia that show potential for success in the contexts of developmental and adult WM pathology. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
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Affiliation(s)
- Li-Jin Chew
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC, USA.
| | - Cynthia A DeBoy
- Biology Department, Trinity Washington University, Washington, DC, USA
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Cardeña-Núñez S, Sánchez-Guardado LÓ, Corral-San-Miguel R, Rodríguez-Gallardo L, Marín F, Puelles L, Aroca P, Hidalgo-Sánchez M. Expression patterns of Irx genes in the developing chick inner ear. Brain Struct Funct 2016; 222:2071-2092. [PMID: 27783221 DOI: 10.1007/s00429-016-1326-6] [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: 05/18/2016] [Accepted: 10/14/2016] [Indexed: 10/20/2022]
Abstract
The vertebrate inner ear is a complex three-dimensional sensorial structure with auditory and vestibular functions. The molecular patterning of the developing otic epithelium creates various positional identities, consequently leading to the stereotyped specification of each neurosensory and non-sensory element of the membranous labyrinth. The Iroquois (Iro/Irx) genes, clustered in two groups (A: Irx1, Irx2, and Irx4; and B: Irx3, Irx5, and Irx6), encode for transcriptional factors involved directly in numerous patterning processes of embryonic tissues in many phyla. This work presents a detailed study of the expression patterns of these six Irx genes during chick inner ear development, paying particular attention to the axial specification of the otic anlagen. The Irx genes seem to play different roles at different embryonic periods. At the otic vesicle stage (HH18), all the genes of each cluster are expressed identically. Both clusters A and B seem involved in the specification of the lateral and posterior portions of the otic anlagen. Cluster B seems to regulate a larger area than cluster A, including the presumptive territory of the endolymphatic apparatus. Both clusters seem also to be involved in neurogenic events. At stages HH24/25-HH27, combinations of IrxA and IrxB genes participate in the specification of most sensory patches and some non-sensory components of the otic epithelium. At stage HH34, the six Irx genes show divergent patterns of expression, leading to the final specification of the membranous labyrinth, as well as to cell differentiation.
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Affiliation(s)
- Sheila Cardeña-Núñez
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain
| | - Luis Óscar Sánchez-Guardado
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain
| | - Rubén Corral-San-Miguel
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Lucía Rodríguez-Gallardo
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain
| | - Faustino Marín
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Pilar Aroca
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Matías Hidalgo-Sánchez
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain.
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Sena E, Feistel K, Durand BC. An Evolutionarily Conserved Network Mediates Development of the zona limitans intrathalamica, a Sonic Hedgehog-Secreting Caudal Forebrain Signaling Center. J Dev Biol 2016; 4:jdb4040031. [PMID: 29615594 PMCID: PMC5831802 DOI: 10.3390/jdb4040031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 09/29/2016] [Accepted: 10/13/2016] [Indexed: 12/16/2022] Open
Abstract
Recent studies revealed new insights into the development of a unique caudal forebrain-signaling center: the zona limitans intrathalamica (zli). The zli is the last brain signaling center to form and the first forebrain compartment to be established. It is the only part of the dorsal neural tube expressing the morphogen Sonic Hedgehog (Shh) whose activity participates in the survival, growth and patterning of neuronal progenitor subpopulations within the thalamic complex. Here, we review the gene regulatory network of transcription factors and cis-regulatory elements that underlies formation of a shh-expressing delimitated domain in the anterior brain. We discuss evidence that this network predates the origin of chordates. We highlight the contribution of Shh, Wnt and Notch signaling to zli development and discuss implications for the fact that the morphogen Shh relies on primary cilia for signal transduction. The network that underlies zli development also contributes to thalamus induction, and to its patterning once the zli has been set up. We present an overview of the brain malformations possibly associated with developmental defects in this gene regulatory network (GRN).
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Affiliation(s)
- Elena Sena
- Institut Curie, Université Paris Sud, INSERM U1021, CNRS UMR3347, Centre Universitaire, Bâtiment 110, F-91405 Orsay Cedex, France.
| | - Kerstin Feistel
- Institute of Zoology, University of Hohenheim, Garbenstr. 30, 70593 Stuttgart, Germany.
| | - Béatrice C Durand
- Institut Curie, Université Paris Sud, INSERM U1021, CNRS UMR3347, Centre Universitaire, Bâtiment 110, F-91405 Orsay Cedex, France.
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Radhakrishnan B, Alwin Prem Anand A. Role of miRNA-9 in Brain Development. J Exp Neurosci 2016; 10:101-120. [PMID: 27721656 PMCID: PMC5053108 DOI: 10.4137/jen.s32843] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/01/2016] [Accepted: 09/07/2016] [Indexed: 02/07/2023] Open
Abstract
MicroRNAs (miRNAs) are a class of small regulatory RNAs involved in gene regulation. The regulation is effected by either translational inhibition or transcriptional silencing. In vertebrates, the importance of miRNA in development was discovered from mice and zebrafish dicer knockouts. The miRNA-9 (miR-9) is one of the most highly expressed miRNAs in the early and adult vertebrate brain. It has diverse functions within the developing vertebrate brain. In this article, the role of miR-9 in the developing forebrain (telencephalon and diencephalon), midbrain, hindbrain, and spinal cord of vertebrate species is highlighted. In the forebrain, miR-9 is necessary for the proper development of dorsoventral telencephalon by targeting marker genes expressed in the telencephalon. It regulates proliferation in telencephalon by regulating Foxg1, Pax6, Gsh2, and Meis2 genes. The feedback loop regulation between miR-9 and Nr2e1/Tlx helps in neuronal migration and differentiation. Targeting Foxp1 and Foxp2, and Map1b by miR-9 regulates the radial migration of neurons and axonal development. In the organizers, miR-9 is inversely regulated by hairy1 and Fgf8 to maintain zona limitans interthalamica and midbrain–hindbrain boundary (MHB). It maintains the MHB by inhibiting Fgf signaling genes and is involved in the neurogenesis of the midbrain–hindbrain by regulating Her genes. In the hindbrain, miR-9 modulates progenitor proliferation and differentiation by regulating Her genes and Elav3. In the spinal cord, miR-9 modulates the regulation of Foxp1 and Onecut1 for motor neuron development. In the forebrain, midbrain, and hindbrain, miR-9 is necessary for proper neuronal progenitor maintenance, neurogenesis, and differentiation. In vertebrate brain development, miR-9 is involved in regulating several region-specific genes in a spatiotemporal pattern.
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Affiliation(s)
| | - A Alwin Prem Anand
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
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38
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Zhang Y, Alvarez-Bolado G. Differential developmental strategies by Sonic hedgehog in thalamus and hypothalamus. J Chem Neuroanat 2016; 75:20-7. [DOI: 10.1016/j.jchemneu.2015.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 11/25/2015] [Indexed: 12/11/2022]
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Halluin C, Madelaine R, Naye F, Peers B, Roussigné M, Blader P. Habenular Neurogenesis in Zebrafish Is Regulated by a Hedgehog, Pax6 Proneural Gene Cascade. PLoS One 2016; 11:e0158210. [PMID: 27387288 PMCID: PMC4936704 DOI: 10.1371/journal.pone.0158210] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 06/13/2016] [Indexed: 11/19/2022] Open
Abstract
The habenulae are highly conserved nuclei in the dorsal diencephalon that connect the forebrain to the midbrain and hindbrain. These nuclei have been implicated in a broad variety of behaviours in humans, primates, rodents and zebrafish. Despite this, the molecular mechanisms that control the genesis and differentiation of neural progenitors in the habenulae remain relatively unknown. We have previously shown that, in zebrafish, the timing of habenular neurogenesis is left-right asymmetric and that in the absence of Nodal signalling this asymmetry is lost. Here, we show that habenular neurogenesis requires the homeobox transcription factor Pax6a and the redundant action of two proneural bHLH factors, Neurog1 and Neurod4. We present evidence that Hedgehog signalling is required for the expression of pax6a, which is in turn necessary for the expression of neurog1 and neurod4. Finally, we demonstrate by pharmacological inhibition that Hedgehog signalling is required continuously during habenular neurogenesis and by cell transplantation experiments that pathway activation is required cell autonomously. Our data sheds light on the mechanism underlying habenular development that may provide insights into how Nodal signalling imposes asymmetry on the timing of habenular neurogenesis.
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Affiliation(s)
- Caroline Halluin
- Université de Toulouse III, UPS, Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), 118 route de Narbonne, F-31062 Toulouse, France
- CNRS, CBD UMR 5547, F-31062 Toulouse, France
- Stanford University, School of Medicine, 269–279 Campus Drive, Stanford, CA 94305, United States of America
| | - Romain Madelaine
- Université de Toulouse III, UPS, Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), 118 route de Narbonne, F-31062 Toulouse, France
- CNRS, CBD UMR 5547, F-31062 Toulouse, France
- Stanford University, School of Medicine, 269–279 Campus Drive, Stanford, CA 94305, United States of America
| | - François Naye
- Unit of Molecular Biology and Genetic Engineering, University of Liège, GIGA-R, B34, Avenue de l'Hôpital 1, B-4000 Liège, Belgium
| | - Bernard Peers
- Unit of Molecular Biology and Genetic Engineering, University of Liège, GIGA-R, B34, Avenue de l'Hôpital 1, B-4000 Liège, Belgium
| | - Myriam Roussigné
- Université de Toulouse III, UPS, Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), 118 route de Narbonne, F-31062 Toulouse, France
- CNRS, CBD UMR 5547, F-31062 Toulouse, France
- * E-mail: (MR); (PB)
| | - Patrick Blader
- Université de Toulouse III, UPS, Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), 118 route de Narbonne, F-31062 Toulouse, France
- CNRS, CBD UMR 5547, F-31062 Toulouse, France
- * E-mail: (MR); (PB)
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40
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Huilgol D, Tole S. Cell migration in the developing rodent olfactory system. Cell Mol Life Sci 2016; 73:2467-90. [PMID: 26994098 PMCID: PMC4894936 DOI: 10.1007/s00018-016-2172-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 02/08/2016] [Accepted: 03/01/2016] [Indexed: 02/06/2023]
Abstract
The components of the nervous system are assembled in development by the process of cell migration. Although the principles of cell migration are conserved throughout the brain, different subsystems may predominantly utilize specific migratory mechanisms, or may display unusual features during migration. Examining these subsystems offers not only the potential for insights into the development of the system, but may also help in understanding disorders arising from aberrant cell migration. The olfactory system is an ancient sensory circuit that is essential for the survival and reproduction of a species. The organization of this circuit displays many evolutionarily conserved features in vertebrates, including molecular mechanisms and complex migratory pathways. In this review, we describe the elaborate migrations that populate each component of the olfactory system in rodents and compare them with those described in the well-studied neocortex. Understanding how the components of the olfactory system are assembled will not only shed light on the etiology of olfactory and sexual disorders, but will also offer insights into how conserved migratory mechanisms may have shaped the evolution of the brain.
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Affiliation(s)
- Dhananjay Huilgol
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
- Cold Spring Harbor Laboratory, Cold Spring Harbor, USA
| | - Shubha Tole
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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41
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Barhl2 Determines the Early Patterning of the Diencephalon by Regulating Shh. Mol Neurobiol 2016; 54:4414-4420. [PMID: 27349434 DOI: 10.1007/s12035-016-0001-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022]
Abstract
The diencephalon is the primary relay network transmitting sensory information to the anterior forebrain. During development, distinct progenitor domains in the diencephalon give rise to the pretectum (p1), the thalamus and epithalamus (p2), and the prethalamus (p3), respectively. Shh plays a significant role in establishing the progenitor domains. However, the upstream events influencing the expression of Shh are largely unknown. Here, we show that Barhl2 homeobox gene is expressed in the p1 and p2 progenitor domains and the in zona limitans intrathalamica (ZLI) and regulates the acquisition of identity of progenitor cells in the developing diencephalon. Targeted deletion of Barhl2 results in the ablation of Shh expression in the dorsal portion of ZLI and causes thalamic p2 progenitors to take the fate of p1 progenitors and form pretectal neurons. Moreover, loss of Barhl2 leads to the absence of thalamocortical axon projections, the loss of habenular afferents and efferents, and a gross diminution of the pineal gland. Thus, by acting upstream of Shh signaling pathway, Barhl2 plays a crucial role in patterning the progenitor domains and establishing the positional identities of progenitor cells in the diencephalon.
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42
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Yao Y, Minor PJ, Zhao YT, Jeong Y, Pani AM, King AN, Symmons O, Gan L, Cardoso WV, Spitz F, Lowe CJ, Epstein DJ. Cis-regulatory architecture of a brain signaling center predates the origin of chordates. Nat Genet 2016; 48:575-80. [PMID: 27064252 PMCID: PMC4848136 DOI: 10.1038/ng.3542] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/11/2016] [Indexed: 12/13/2022]
Abstract
Genomic approaches have predicted hundreds of thousands of tissue-specific cis-regulatory sequences, but the determinants critical to their function and evolutionary history are mostly unknown. Here we systematically decode a set of brain enhancers active in the zona limitans intrathalamica (zli), a signaling center essential for vertebrate forebrain development via the secreted morphogen Sonic hedgehog (Shh). We apply a de novo motif analysis tool to identify six position-independent sequence motifs together with their cognate transcription factors that are essential for zli enhancer activity and Shh expression in the mouse embryo. Using knowledge of this regulatory lexicon, we discover new Shh zli enhancers in mice and a functionally equivalent element in hemichordates, indicating an ancient origin of the Shh zli regulatory network that predates the chordate phylum. These findings support a strategy for delineating functionally conserved enhancers in the absence of overt sequence homologies and over extensive evolutionary distances.
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Affiliation(s)
- Yao Yao
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, 415 Curie Blvd, Clinical Research Building 470, Philadelphia, PA 19104, USA
| | - Paul J. Minor
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd. Pacific Grove, CA 93950, USA
| | - Ying-Tao Zhao
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, 415 Curie Blvd, Clinical Research Building 470, Philadelphia, PA 19104, USA
| | - Yongsu Jeong
- Department of Genetic Engineering, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Yongin-si 446-701, Republic of Korea
| | - Ariel M. Pani
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd. Pacific Grove, CA 93950, USA
| | - Anna N. King
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, 415 Curie Blvd, Clinical Research Building 470, Philadelphia, PA 19104, USA
| | - Orsolya Symmons
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Lin Gan
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Wellington V. Cardoso
- Columbia Center for Human Development, Department of Medicine, Pulmonary Allergy Critical Care, Columbia University Medical Center, New York, NY 10032, USA
| | - François Spitz
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christopher J. Lowe
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd. Pacific Grove, CA 93950, USA
| | - Douglas J. Epstein
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, 415 Curie Blvd, Clinical Research Building 470, Philadelphia, PA 19104, USA
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Denham M, Hasegawa K, Menheniott T, Rollo B, Zhang D, Hough S, Alshawaf A, Febbraro F, Ighaniyan S, Leung J, Elliott DA, Newgreen DF, Pera MF, Dottori M. Multipotent caudal neural progenitors derived from human pluripotent stem cells that give rise to lineages of the central and peripheral nervous system. Stem Cells 2016; 33:1759-70. [PMID: 25753817 PMCID: PMC5347855 DOI: 10.1002/stem.1991] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 12/25/2014] [Accepted: 01/17/2015] [Indexed: 01/22/2023]
Abstract
The caudal neural plate is a distinct region of the embryo that gives rise to major progenitor lineages of the developing central and peripheral nervous system, including neural crest and floor plate cells. We show that dual inhibition of the glycogen synthase kinase 3β and activin/nodal pathways by small molecules differentiate human pluripotent stem cells (hPSCs) directly into a preneuroepithelial progenitor population we named “caudal neural progenitors” (CNPs). CNPs coexpress caudal neural plate and mesoderm markers, and, share high similarities to embryonic caudal neural plate cells in their lineage differentiation potential. Exposure of CNPs to BMP2/4, sonic hedgehog, or FGF2 signaling efficiently directs their fate to neural crest/roof plate cells, floor plate cells, and caudally specified neuroepithelial cells, respectively. Neural crest derived from CNPs differentiated to neural crest derivatives and demonstrated extensive migratory properties in vivo. Importantly, we also determined the key extrinsic factors specifying CNPs from human embryonic stem cell include FGF8, canonical WNT, and IGF1. Our studies are the first to identify a multipotent neural progenitor derived from hPSCs, that is the precursor for major neural lineages of the embryonic caudal neural tube. Stem Cells2015;33:1759–1770
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Affiliation(s)
- Mark Denham
- Department of Anatomy and Neurosciences, University of Melbourne, Melbourne, Australia.,Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark
| | - Kouichi Hasegawa
- Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan.,InStem, NCBS, Bangalore, Karnataka, India
| | | | - Ben Rollo
- Murdoch Children's Research Institute, Melbourne, Australia
| | | | - Shelley Hough
- Department of Anatomy and Neurosciences, University of Melbourne, Melbourne, Australia
| | - Abdullah Alshawaf
- Centre for Neural Engineering, Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Australia
| | - Fabia Febbraro
- Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark
| | | | - Jessie Leung
- Department of Anatomy and Neurosciences, University of Melbourne, Melbourne, Australia
| | | | | | - Martin F Pera
- Department of Anatomy and Neurosciences, University of Melbourne, Melbourne, Australia.,Walter and Eliza Hall Institute, Melbourne, Australia.,Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Mirella Dottori
- Department of Anatomy and Neurosciences, University of Melbourne, Melbourne, Australia.,Centre for Neural Engineering, Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Australia
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44
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Abstract
An "organizer" is formally defined as a region, or group of cells in an embryo that can both induce (change the fate) and pattern (generate an organized set of structures) adjacent embryonic cells. To date, about four such regions have been demonstrated: the primary or Spemann organizer (Hensen's node in amniotes), the notochord, the zone of polarizing activity of the limb bud, and the mid-hindbrain boundary. Here we review the evidence for these and compare them with a few other regions which have been proposed to represent other organizers and we speculate on why so few such regions have been discovered.
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Affiliation(s)
- Claire Anderson
- Department of Cell & Developmental Biology, University College London, London, United Kingdom
| | - Claudio D Stern
- Department of Cell & Developmental Biology, University College London, London, United Kingdom.
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45
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Clegg JM, Li Z, Molinek M, Caballero IM, Manuel MN, Price DJ. Pax6 is required intrinsically by thalamic progenitors for the normal molecular patterning of thalamic neurons but not the growth and guidance of their axons. Neural Dev 2015; 10:26. [PMID: 26520399 PMCID: PMC4628245 DOI: 10.1186/s13064-015-0053-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 10/23/2015] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND In mouse embryos, the Pax6 transcription factor is expressed in the progenitors of thalamic neurons but not in thalamic neurons themselves. Its null-mutation causes early mis-patterning of thalamic progenitors. It is known that thalamic neurons generated by Pax6 (-/-) progenitors do not develop their normal connections with the cortex, but it is not clear why. We investigated the extent to which defects intrinsic to the thalamus are responsible. RESULTS We first confirmed that, in constitutive Pax6 (-/-) mutants, the axons of thalamic neurons fail to enter the telencephalon and, instead, many of them take an abnormal path to the hypothalamus, whose expression of Slits would normally repel them. We found that thalamic neurons show reduced expression of the Slit receptor Robo2 in Pax6 (-/-) mutants, which might enhance the ability of their axons to enter the hypothalamus. Remarkably, however, in chimeras comprising a mixture of Pax6 (-/-) and Pax6 (+/+) cells, Pax6 (-/-) thalamic neurons are able to generate axons that exit the diencephalon, take normal trajectories through the telencephalon and avoid the hypothalamus. This occurs despite abnormalities in their molecular patterning (they express Nkx2.2, unlike normal thalamic neurons) and their reduced expression of Robo2. In conditional mutants, acute deletion of Pax6 from the forebrain at the time when thalamic axons are starting to grow does not prevent the development of the thalamocortical tract, suggesting that earlier extra-thalamic patterning and /or morphological defects are the main cause of thalamocortical tract failure in Pax6 (-/-) constitutive mutants. CONCLUSIONS Our results indicate that Pax6 is required by thalamic progenitors for the normal molecular patterning of the thalamic neurons that they generate but thalamic neurons do not need normal Pax6-dependent patterning to become competent to grow axons that can be guided appropriately.
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Affiliation(s)
- James M Clegg
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
| | - Ziwen Li
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
| | - Michael Molinek
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
| | - Isabel Martín Caballero
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
- Current address: Laboratory of Molecular Neurobiology, Karolinska Institute, 17177, Scheeles Väg 1, Sweden.
| | - Martine N Manuel
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
| | - David J Price
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
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46
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Miquelajáuregui A, Sandoval-Schaefer T, Martínez-Armenta M, Pérez-Martínez L, Cárabez A, Zhao Y, Heide M, Alvarez-Bolado G, Varela-Echavarría A. LIM homeobox protein 5 (Lhx5) is essential for mamillary body development. Front Neuroanat 2015; 9:136. [PMID: 26578897 PMCID: PMC4621302 DOI: 10.3389/fnana.2015.00136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/12/2015] [Indexed: 02/01/2023] Open
Abstract
The mamillary body (MM) is a group of hypothalamic nuclei related to memory and spatial navigation that interconnects hippocampal, thalamic, and tegmental regions. Here we demonstrate that Lhx5, a LIM-HD domain transcription factor expressed early in the developing posterior hypothalamus, is required for the generation of the MM and its derived tracts. The MM markers Foxb1, Sim2, and Lhx1 are absent in Lhx5 knock-out mice from early embryonic stages, suggesting abnormal specification of this region. This was supported by the absence of Nkx2.1 and expansion of Shh in the prospective mamillary area. Interestingly, we also found an ectopic domain expressing Lhx2 and Lhx9 along the anterio-posterior hypothalamic axis. Our results suggest that Lhx5 controls early aspects of hypothalamic development by regulating gene expression and cellular specification in the prospective MM.
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Affiliation(s)
- Amaya Miquelajáuregui
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Teresa Sandoval-Schaefer
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Miriam Martínez-Armenta
- Laboratorio de Neuroinmunobiología, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México Cuernavaca, Mexico
| | - Leonor Pérez-Martínez
- Laboratorio de Neuroinmunobiología, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México Cuernavaca, Mexico
| | - Alfonso Cárabez
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Yangu Zhao
- Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA
| | - Michael Heide
- Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | | | - Alfredo Varela-Echavarría
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
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47
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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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48
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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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49
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Martinez-Ferre A, Lloret-Quesada C, Prakash N, Wurst W, Rubenstein JLR, Martinez S. Fgf15 regulates thalamic development by controlling the expression of proneural genes. Brain Struct Funct 2015; 221:3095-109. [PMID: 26311466 DOI: 10.1007/s00429-015-1089-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/21/2015] [Indexed: 01/01/2023]
Abstract
The establishment of the brain structural complexity requires a precisely orchestrated interplay between extrinsic and intrinsic signals modulating cellular mechanisms to guide neuronal differentiation. However, little is known about the nature of these signals in the diencephalon, a complex brain region that processes and relays sensory and motor information to and from the cerebral cortex and subcortical structures. Morphogenetic signals from brain organizers regulate histogenetic processes such as cellular proliferation, migration, and differentiation. Sonic hedgehog (Shh) in the key signal of the ZLI, identified as the diencephalic organizer. Fgf15, the mouse gene orthologous of human, chick, and zebrafish Fgf19, is induced by Shh signal and expressed in the diencephalic alar plate progenitors during histogenetic developmental stages. This work investigates the role of Fgf15 signal in diencephalic development. In the absence of Fgf15, the complementary expression pattern of proneural genes: Ascl1 and Nng2, is disrupted and the GABAergic thalamic cells do not differentiate; in addition dorsal thalamic progenitors failed to exit from the mitotic cycle and to differentiate into neurons. Therefore, our findings indicate that Fgf15 is the Shh downstream signal to control thalamic regionalization, neurogenesis, and neuronal differentiation by regulating the expression and mutual segregation of neurogenic and proneural regulatory genes.
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Affiliation(s)
- Almudena Martinez-Ferre
- Instituto Murciano de Investigación Biosanitaria (IMIB-Arrixaca), University of Murcia, 30120, El Palmar, Murcia, Spain
| | - Cosme Lloret-Quesada
- Institute of Neurosciences, Miguel Hernández University, Spanish National Research Council, San Juan Campus, 03550, Sant Joan d'Alacant, Alicante, Spain
| | - Nilima Prakash
- Institute of Developmental Genetics, Helmholtz Centre Munich, German Research Centre for Environmental Health (GmbH), Technical University Munich, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Centre Munich, German Research Centre for Environmental Health (GmbH), Technical University Munich, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany
| | - John L R Rubenstein
- Department of Psychiatry, Nina Ireland Laboratory of Developmental Neurobiology, University of California San Francisco, San Francisco, CA, USA
| | - Salvador Martinez
- Instituto Murciano de Investigación Biosanitaria (IMIB-Arrixaca), University of Murcia, 30120, El Palmar, Murcia, Spain. .,Institute of Neurosciences, Miguel Hernández University, Spanish National Research Council, San Juan Campus, 03550, Sant Joan d'Alacant, Alicante, Spain. .,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Valencia, Spain.
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50
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Ziats MN, Edmonson C, Rennert OM. The autistic brain in the context of normal neurodevelopment. Front Neuroanat 2015; 9:115. [PMID: 26379512 PMCID: PMC4548149 DOI: 10.3389/fnana.2015.00115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 08/12/2015] [Indexed: 01/06/2023] Open
Abstract
The etiology of autism spectrum disorders (ASDs) is complex and largely unclear. Among various lines of inquiry, many have suggested convergence onto disruptions in both neural circuitry and immune regulation/glial cell function pathways. However, the interpretation of the relationship between these two putative mechanisms has largely focused on the role of exogenous factors and insults, such as maternal infection, in activating immune pathways that in turn result in neural network abnormalities. Yet, given recent insights into our understanding of human neurodevelopment, and in particular the critical role of glia and the immune system in normal brain development, it is important to consider these putative pathological processes in their appropriate normal neurodevelopmental context. In this review, we explore the hypothesis that the autistic brain cellular phenotype likely represents intrinsic abnormalities of glial/immune processes constitutively operant in normal brain development that result in the observed neural network dysfunction. We review recent studies demonstrating the intercalated role of neural circuit development, the immune system, and glial cells in the normal developing brain, and integrate them with studies demonstrating pathological alterations in these processes in autism. By discussing known abnormalities in the autistic brain in the context of normal brain development, we explore the hypothesis that the glial/immune component of ASD may instead be related to intrinsic exaggerated/abnormal constitutive neurodevelopmental processes such as network pruning. Moreover, this hypothesis may be relevant to other neurodevelopmental disorders that share genetic, pathologic, and clinical features with autism.
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Affiliation(s)
- Mark N Ziats
- National Institute of Child Health and Human Development, NIH Bethesda, MD, USA ; Medical Scientist Training Program, Baylor College of Medicine Houston, TX, USA
| | - Catherine Edmonson
- National Institute of Child Health and Human Development, NIH Bethesda, MD, USA ; College of Medicine, University of Florida Gainesville, FL, USA
| | - Owen M Rennert
- National Institute of Child Health and Human Development, NIH Bethesda, MD, USA
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