1
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Kratsios P, Zampieri N, Carrillo R, Mizumoto K, Sweeney LB, Philippidou P. Molecular and Cellular Mechanisms of Motor Circuit Development. J Neurosci 2024; 44:e1238242024. [PMID: 39358025 PMCID: PMC11450535 DOI: 10.1523/jneurosci.1238-24.2024] [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: 06/30/2024] [Revised: 07/22/2024] [Accepted: 07/23/2024] [Indexed: 10/04/2024] Open
Abstract
Motor circuits represent the main output of the central nervous system and produce dynamic behaviors ranging from relatively simple rhythmic activities like swimming in fish and breathing in mammals to highly sophisticated dexterous movements in humans. Despite decades of research, the development and function of motor circuits remain poorly understood. Breakthroughs in the field recently provided new tools and tractable model systems that set the stage to discover the molecular mechanisms and circuit logic underlying motor control. Here, we describe recent advances from both vertebrate (mouse, frog) and invertebrate (nematode, fruit fly) systems on cellular and molecular mechanisms that enable motor circuits to develop and function and highlight conserved and divergent mechanisms necessary for motor circuit development.
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Affiliation(s)
- Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, Illinois 60637
- Neuroscience Institute, University of Chicago, Chicago, Illinois 60637
| | - Niccolò Zampieri
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin 13125, Germany
| | - Robert Carrillo
- Neuroscience Institute, University of Chicago, Chicago, Illinois 60637
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Kota Mizumoto
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Lora B Sweeney
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | - Polyxeni Philippidou
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106
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2
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Kc R, López de Boer R, Lin M, Vagnozzi AN, Jeannotte L, Philippidou P. Multimodal Hox5 activity generates motor neuron diversity. Commun Biol 2024; 7:1166. [PMID: 39289460 PMCID: PMC11408534 DOI: 10.1038/s42003-024-06835-w] [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: 12/17/2023] [Accepted: 09/03/2024] [Indexed: 09/19/2024] Open
Abstract
Motor neurons (MNs) are the final output of circuits driving fundamental behaviors, such as respiration and locomotion. Hox proteins are essential in generating the MN diversity required for accomplishing these functions, but the transcriptional mechanisms that enable Hox paralogs to assign distinct MN subtype identities despite their promiscuous DNA binding motif are not well understood. Here we show that Hoxa5 modifies chromatin accessibility in all mouse spinal cervical MN subtypes and engages TALE co-factors to directly bind and regulate subtype-specific genes. We identify a paralog-specific interaction of Hoxa5 with the phrenic MN-specific transcription factor Scip and show that heterologous expression of Hoxa5 and Scip is sufficient to suppress limb-innervating MN identity. We also demonstrate that phrenic MN identity is stable after Hoxa5 downregulation and identify Klf proteins as potential regulators of phrenic MN maintenance. Our data identify multiple modes of Hoxa5 action that converge to induce and maintain MN identity.
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Affiliation(s)
- Ritesh Kc
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Raquel López de Boer
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Minshan Lin
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Alicia N Vagnozzi
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Lucie Jeannotte
- Department of Molecular Biology, Medical Biochemistry & Pathology, Université Laval, Centre Recherche sur le Cancer de l'Université Laval, Centre de recherche du CHU de Québec-Université Laval (Oncology), Québec, Canada
| | - Polyxeni Philippidou
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.
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3
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Ritesh KC, de Boer RL, Lin M, Jeannotte L, Philippidou P. Multimodal Hox5 activity generates motor neuron diversity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.08.579338. [PMID: 38370781 PMCID: PMC10871347 DOI: 10.1101/2024.02.08.579338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Motor neurons (MNs) are the final output of circuits driving fundamental behaviors, such as respiration and locomotion. Hox proteins are essential in generating the MN diversity required for accomplishing these functions, but the transcriptional mechanisms that enable Hox paralogs to assign distinct MN subtype identities despite their promiscuous DNA binding motif are not well understood. Here we show that Hoxa5 controls chromatin accessibility in all mouse spinal cervical MN subtypes and engages TALE co-factors to directly bind and regulate subtype-specific genes. We identify a paralog-specific interaction of Hoxa5 with the phrenic MN-specific transcription factor Scip and show that heterologous expression of Hoxa5 and Scip is sufficient to suppress limb-innervating MN identity. We also demonstrate that phrenic MN identity is stable after Hoxa5 downregulation and identify Klf proteins as potential regulators of phrenic MN maintenance. Our data identify multiple modes of Hoxa5 action that converge to induce and maintain MN identity.
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Affiliation(s)
- K C Ritesh
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Raquel López de Boer
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Minshan Lin
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Lucie Jeannotte
- Department of Molecular Biology, Medical Biochemistry & Pathology, Université Laval, Centre Recherche sur le Cancer de l'Université Laval, Centre de recherche du CHU de Québec-Université Laval (Oncology), Québec, Canada
| | - Polyxeni Philippidou
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
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4
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Miller A, Dasen JS. Establishing and maintaining Hox profiles during spinal cord development. Semin Cell Dev Biol 2024; 152-153:44-57. [PMID: 37029058 PMCID: PMC10524138 DOI: 10.1016/j.semcdb.2023.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 03/30/2023] [Indexed: 04/09/2023]
Abstract
The chromosomally-arrayed Hox gene family plays central roles in embryonic patterning and the specification of cell identities throughout the animal kingdom. In vertebrates, the relatively large number of Hox genes and pervasive expression throughout the body has hindered understanding of their biological roles during differentiation. Studies on the subtype diversification of spinal motor neurons (MNs) have provided a tractable system to explore the function of Hox genes during differentiation, and have provided an entry point to explore how neuronal fate determinants contribute to motor circuit assembly. Recent work, using both in vitro and in vivo models of MN subtype differentiation, have revealed how patterning morphogens and regulation of chromatin structure determine cell-type specific programs of gene expression. These studies have not only shed light on basic mechanisms of rostrocaudal patterning in vertebrates, but also have illuminated mechanistic principles of gene regulation that likely operate in the development and maintenance of terminal fates in other systems.
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Affiliation(s)
- Alexander Miller
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
| | - Jeremy S Dasen
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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5
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Abstract
Hox genes encode evolutionarily conserved transcription factors that are essential for the proper development of bilaterian organisms. Hox genes are unique because they are spatially and temporally regulated during development in a manner that is dictated by their tightly linked genomic organization. Although their genetic function during embryonic development has been interrogated, less is known about how these transcription factors regulate downstream genes to direct morphogenetic events. Moreover, the continued expression and function of Hox genes at postnatal and adult stages highlights crucial roles for these genes throughout the life of an organism. Here, we provide an overview of Hox genes, highlighting their evolutionary history, their unique genomic organization and how this impacts the regulation of their expression, what is known about their protein structure, and their deployment in development and beyond.
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Affiliation(s)
- Katharine A. Hubert
- Program in Genetics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Deneen M. Wellik
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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6
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Yoo D, Park J, Lee C, Song I, Lee YH, Yun T, Lee H, Heguy A, Han JY, Dasen JS, Kim H, Baek M. Little skate genome provides insights into genetic programs essential for limb-based locomotion. eLife 2022; 11:e78345. [PMID: 36288084 PMCID: PMC9605692 DOI: 10.7554/elife.78345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
The little skate Leucoraja erinacea, a cartilaginous fish, displays pelvic fin driven walking-like behavior using genetic programs and neuronal subtypes similar to those of land vertebrates. However, mechanistic studies on little skate motor circuit development have been limited, due to a lack of high-quality reference genome. Here, we generated an assembly of the little skate genome, with precise gene annotation and structures, which allowed post-genome analysis of spinal motor neurons (MNs) essential for locomotion. Through interspecies comparison of mouse, skate and chicken MN transcriptomes, shared and divergent gene expression profiles were identified. Comparison of accessible chromatin regions between mouse and skate MNs predicted shared transcription factor (TF) motifs with divergent ones, which could be used for achieving differential regulation of MN-expressed genes. A greater number of TF motif predictions were observed in MN-expressed genes in mouse than in little skate. These findings suggest conserved and divergent molecular mechanisms controlling MN development of vertebrates during evolution, which might contribute to intricate gene regulatory networks in the emergence of a more sophisticated motor system in tetrapods.
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Affiliation(s)
- DongAhn Yoo
- Interdisciplinary Program in Bioinformatics, Seoul National UniversitySeoulRepublic of Korea
| | - Junhee Park
- Department of Brain Sciences, DGISTDaeguRepublic of Korea
| | - Chul Lee
- Interdisciplinary Program in Bioinformatics, Seoul National UniversitySeoulRepublic of Korea
| | - Injun Song
- Department of Brain Sciences, DGISTDaeguRepublic of Korea
| | - Young Ho Lee
- Interdisciplinary Program in Bioinformatics, Seoul National UniversitySeoulRepublic of Korea
| | - Tery Yun
- Department of Brain Sciences, DGISTDaeguRepublic of Korea
| | - Hyemin Lee
- Department of Biology, Graduate School of Arts and Science, NYUNew YorkUnited States
| | - Adriana Heguy
- Genome Technology Center, Division for Advanced Research Technologies, and Department of Pathology, NYU School of MedicineNew YorkUnited States
| | - Jae Yong Han
- Department of Agricultural Biotechnology, Seoul National UniversitySeoulRepublic of Korea
| | - Jeremy S Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of MedicineNew YorkUnited States
| | - Heebal Kim
- Interdisciplinary Program in Bioinformatics, Seoul National UniversitySeoulRepublic of Korea
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National UniversitySeoulRepublic of Korea
- eGnome, IncSeoulRepublic of Korea
| | - Myungin Baek
- Department of Brain Sciences, DGISTDaeguRepublic of Korea
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7
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Singh NP, Krumlauf R. Diversification and Functional Evolution of HOX Proteins. Front Cell Dev Biol 2022; 10:798812. [PMID: 35646905 PMCID: PMC9136108 DOI: 10.3389/fcell.2022.798812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/08/2022] [Indexed: 01/07/2023] Open
Abstract
Gene duplication and divergence is a major contributor to the generation of morphological diversity and the emergence of novel features in vertebrates during evolution. The availability of sequenced genomes has facilitated our understanding of the evolution of genes and regulatory elements. However, progress in understanding conservation and divergence in the function of proteins has been slow and mainly assessed by comparing protein sequences in combination with in vitro analyses. These approaches help to classify proteins into different families and sub-families, such as distinct types of transcription factors, but how protein function varies within a gene family is less well understood. Some studies have explored the functional evolution of closely related proteins and important insights have begun to emerge. In this review, we will provide a general overview of gene duplication and functional divergence and then focus on the functional evolution of HOX proteins to illustrate evolutionary changes underlying diversification and their role in animal evolution.
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Affiliation(s)
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, United States
- Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS, United States
- *Correspondence: Robb Krumlauf,
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8
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Needham J, Metzis V. Heads or tails: Making the spinal cord. Dev Biol 2022; 485:80-92. [DOI: 10.1016/j.ydbio.2022.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/15/2021] [Accepted: 03/02/2022] [Indexed: 12/14/2022]
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9
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Zheng C, Lee HMT, Pham K. Nervous system-wide analysis of Hox regulation of terminal neuronal fate specification in Caenorhabditis elegans. PLoS Genet 2022; 18:e1010092. [PMID: 35226663 PMCID: PMC8912897 DOI: 10.1371/journal.pgen.1010092] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/10/2022] [Accepted: 02/12/2022] [Indexed: 12/01/2022] Open
Abstract
Hox genes encode evolutionarily conserved transcription factors that specify regional identities along the anterior-posterior (A-P) axis. Although some Hox genes are known to regulate the differentiation of certain neurons, to what extent Hox genes are involved in the terminal specification of the entire nervous system is unclear. Here, we systematically mapped the expression of all six Hox genes in C. elegans nervous system and found Hox expression in 97 (32%) of the 302 neurons in adult hermaphrodites. Our results are generally consistent with previous high-throughput expression mapping and single-cell transcriptomic studies. Detailed analysis of the fate markers for these neurons revealed that Hox genes regulate the differentiation of 29 (25%) of the 118 classes of C. elegans neurons. Hox genes not only regulate the specification of terminal neuronal fates through multiple mechanisms but also control subtype diversification along the A-P axis. The widespread involvement of Hox genes in neuronal differentiation indicates their roles in establishing complex nervous systems. The nervous system contains an extraordinary array of neuron types. How this neuronal diversity arises during development and what genes regulate the differentiation of each neuron type are among the major questions of neurobiology. Hox genes are a set of transcription factors highly conserved in the animal kingdom and are involved in setting up the body plan in the embryos. Hox genes are known to regulate the differentiation of some neurons, but their contribution to the overall development of a nervous system is unclear. In this study, we analyzed the activity of the Hox genes in the differentiation of the 302 neurons of the C. elegans nervous system in its entirety. We found that the six Hox genes are expressed in 32% of all neurons and five Hox genes regulate the differentiation of 25% of all neuron types through multiple mechanisms and act at various stages of cellular development. Thus, our results suggest that a small number of Hox genes could control the development of a significant portion of the nervous system. Given the conserved functions of Hox genes across species, we suspect that the increasing number of Hox genes may have allowed increased complexity in the nervous system in animal evolution.
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Affiliation(s)
- Chaogu Zheng
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
- * E-mail:
| | - Ho Ming Terence Lee
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Kenneth Pham
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
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10
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Joshi R, Sipani R, Bakshi A. Roles of Drosophila Hox Genes in the Assembly of Neuromuscular Networks and Behavior. Front Cell Dev Biol 2022; 9:786993. [PMID: 35071230 PMCID: PMC8777297 DOI: 10.3389/fcell.2021.786993] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes have been known for specifying the anterior-posterior axis (AP) in bilaterian body plans. Studies in vertebrates have shown their importance in developing region-specific neural circuitry and diversifying motor neuron pools. In Drosophila, they are instrumental for segment-specific neurogenesis and myogenesis early in development. Their robust expression in differentiated neurons implied their role in assembling region-specific neuromuscular networks. In the last decade, studies in Drosophila have unequivocally established that Hox genes go beyond their conventional functions of generating cellular diversity along the AP axis of the developing central nervous system. These roles range from establishing and maintaining the neuromuscular networks to controlling their function by regulating the motor neuron morphology and neurophysiology, thereby directly impacting the behavior. Here we summarize the limited knowledge on the role of Drosophila Hox genes in the assembly of region-specific neuromuscular networks and their effect on associated behavior.
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Affiliation(s)
- Rohit Joshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
| | - Rashmi Sipani
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Asif Bakshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
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11
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Dasen JS. Establishing the Molecular and Functional Diversity of Spinal Motoneurons. ADVANCES IN NEUROBIOLOGY 2022; 28:3-44. [PMID: 36066819 DOI: 10.1007/978-3-031-07167-6_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Spinal motoneurons are a remarkably diverse class of neurons responsible for facilitating a broad range of motor behaviors and autonomic functions. Studies of motoneuron differentiation have provided fundamental insights into the developmental mechanisms of neuronal diversification, and have illuminated principles of neural fate specification that operate throughout the central nervous system. Because of their relative anatomical simplicity and accessibility, motoneurons have provided a tractable model system to address multiple facets of neural development, including early patterning, neuronal migration, axon guidance, and synaptic specificity. Beyond their roles in providing direct communication between central circuits and muscle, recent studies have revealed that motoneuron subtype-specific programs also play important roles in determining the central connectivity and function of motor circuits. Cross-species comparative analyses have provided novel insights into how evolutionary changes in subtype specification programs may have contributed to adaptive changes in locomotor behaviors. This chapter focusses on the gene regulatory networks governing spinal motoneuron specification, and how studies of spinal motoneurons have informed our understanding of the basic mechanisms of neuronal specification and spinal circuit assembly.
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Affiliation(s)
- Jeremy S Dasen
- NYU Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA.
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12
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Poliacikova G, Maurel-Zaffran C, Graba Y, Saurin AJ. Hox Proteins in the Regulation of Muscle Development. Front Cell Dev Biol 2021; 9:731996. [PMID: 34733846 PMCID: PMC8558437 DOI: 10.3389/fcell.2021.731996] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes encode evolutionary conserved transcription factors that specify the anterior-posterior axis in all bilaterians. Being well known for their role in patterning ectoderm-derivatives, such as CNS and spinal cord, Hox protein function is also crucial in mesodermal patterning. While well described in the case of the vertebrate skeleton, much less is known about Hox functions in the development of different muscle types. In contrast to vertebrates however, studies in the fruit fly, Drosophila melanogaster, have provided precious insights into the requirement of Hox at multiple stages of the myogenic process. Here, we provide a comprehensive overview of Hox protein function in Drosophila and vertebrate muscle development, with a focus on the molecular mechanisms underlying target gene regulation in this process. Emphasizing a tight ectoderm/mesoderm cross talk for proper locomotion, we discuss shared principles between CNS and muscle lineage specification and the emerging role of Hox in neuromuscular circuit establishment.
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Affiliation(s)
| | | | - Yacine Graba
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
| | - Andrew J Saurin
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
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13
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Imai F, Adam M, Potter SS, Yoshida Y. HoxD transcription factors define monosynaptic sensory-motor specificity in the developing spinal cord. Development 2021; 148:269156. [PMID: 34128984 DOI: 10.1242/dev.191122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/17/2021] [Indexed: 12/21/2022]
Abstract
The specificity of monosynaptic connections between proprioceptive sensory neurons and their recipient spinal motor neurons depends on multiple factors, including motor neuron positioning and dendrite morphology, axon projection patterns of proprioceptive sensory neurons in the spinal cord, and the ligand-receptor molecules involved in cell-to-cell recognition. However, with few exceptions, the transcription factors engaged in this process are poorly characterized. Here, we show that members of the HoxD family of transcription factors play a crucial role in the specificity of monosynaptic sensory-motor connections. Mice lacking Hoxd9, Hoxd10 and Hoxd11 exhibit defects in locomotion but have no obvious defects in motor neuron positioning or dendrite morphology through the medio-lateral and rostro-caudal axes. However, we found that quadriceps motor neurons in these mice show aberrant axon development and receive inappropriate inputs from proprioceptive sensory axons innervating the obturator muscle. These genetic studies demonstrate that the HoxD transcription factors play an integral role in the synaptic specificity of monosynaptic sensory-motor connections in the developing spinal cord.
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Affiliation(s)
- Fumiyasu Imai
- Neural Connectivity Development in Physiology and Disease Laboratory, Burke Neurological Institute, White Plains, NY 10605, USA.,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Mike Adam
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - S Steven Potter
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Yutaka Yoshida
- Neural Connectivity Development in Physiology and Disease Laboratory, Burke Neurological Institute, White Plains, NY 10605, USA.,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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14
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Wind M, Gogolou A, Manipur I, Granata I, Butler L, Andrews PW, Barbaric I, Ning K, Guarracino MR, Placzek M, Tsakiridis A. Defining the signalling determinants of a posterior ventral spinal cord identity in human neuromesodermal progenitor derivatives. Development 2021; 148:dev194415. [PMID: 33658223 PMCID: PMC8015249 DOI: 10.1242/dev.194415] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 02/23/2021] [Indexed: 12/14/2022]
Abstract
The anteroposterior axial identity of motor neurons (MNs) determines their functionality and vulnerability to neurodegeneration. Thus, it is a crucial parameter in the design of strategies aiming to produce MNs from human pluripotent stem cells (hPSCs) for regenerative medicine/disease modelling applications. However, the in vitro generation of posterior MNs corresponding to the thoracic/lumbosacral spinal cord has been challenging. Although the induction of cells resembling neuromesodermal progenitors (NMPs), the bona fide precursors of the spinal cord, offers a promising solution, the progressive specification of posterior MNs from these cells is not well defined. Here, we determine the signals guiding the transition of human NMP-like cells toward thoracic ventral spinal cord neurectoderm. We show that combined WNT-FGF activities drive a posterior dorsal pre-/early neural state, whereas suppression of TGFβ-BMP signalling pathways promotes a ventral identity and neural commitment. Based on these results, we define an optimised protocol for the generation of thoracic MNs that can efficiently integrate within the neural tube of chick embryos. We expect that our findings will facilitate the comparison of hPSC-derived spinal cord cells of distinct axial identities.
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Affiliation(s)
- Matthew Wind
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
- Department of Neuroscience, Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Antigoni Gogolou
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
- Department of Neuroscience, Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Ichcha Manipur
- Computational and Data Science Laboratory, High Performance Computing and Networking Institute, National Research Council of Italy, Napoli 80131, Italy
| | - Ilaria Granata
- Computational and Data Science Laboratory, High Performance Computing and Networking Institute, National Research Council of Italy, Napoli 80131, Italy
| | - Larissa Butler
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
| | - Peter W Andrews
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
| | - Ivana Barbaric
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
| | - Ke Ning
- Department of Neuroscience, Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
- Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | | | - Marysia Placzek
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Anestis Tsakiridis
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
- Department of Neuroscience, Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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15
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Wilmerding A, Rinaldi L, Caruso N, Lo Re L, Bonzom E, Saurin AJ, Graba Y, Delfini MC. HoxB genes regulate neuronal delamination in the trunk neural tube by controlling the expression of Lzts1. Development 2021; 148:dev.195404. [PMID: 33472847 DOI: 10.1242/dev.195404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 01/11/2021] [Indexed: 01/23/2023]
Abstract
Differential Hox gene expression is central for specification of axial neuronal diversity in the spinal cord. Here, we uncover an additional function of Hox proteins in the developing spinal cord, restricted to B cluster Hox genes. We found that members of the HoxB cluster are expressed in the trunk neural tube of chicken embryo earlier than Hox from the other clusters, with poor antero-posterior axial specificity and with overlapping expression in the intermediate zone (IZ). Gain-of-function experiments of HoxB4, HoxB8 and HoxB9, respectively, representative of anterior, central and posterior HoxB genes, resulted in ectopic progenitor cells in the mantle zone. The search for HoxB8 downstream targets in the early neural tube identified the leucine zipper tumor suppressor 1 gene (Lzts1), the expression of which is also activated by HoxB4 and HoxB9. Gain- and loss-of-function experiments showed that Lzts1, which is expressed endogenously in the IZ, controls neuronal delamination. These data collectively indicate that HoxB genes have a generic function in the developing spinal cord, controlling the expression of Lzts1 and neuronal delamination.
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Affiliation(s)
| | | | - Nathalie Caruso
- Aix Marseille University, CNRS, IBDM, 13288 Marseille, France
| | - Laure Lo Re
- Aix Marseille University, CNRS, IBDM, 13288 Marseille, France
| | - Emilie Bonzom
- Aix Marseille University, CNRS, IBDM, 13288 Marseille, France
| | - Andrew J Saurin
- Aix Marseille University, CNRS, IBDM, 13288 Marseille, France
| | - Yacine Graba
- Aix Marseille University, CNRS, IBDM, 13288 Marseille, France
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16
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Sun XJ, Li MX, Gong CZ, Chen J, Nasb M, Shah SZA, Rehan M, Li YJ, Chen H. Temporal expression profiles of lncRNA and mRNA in human embryonic stem cell-derived motor neurons during differentiation. PeerJ 2020; 8:e10075. [PMID: 33240592 PMCID: PMC7668206 DOI: 10.7717/peerj.10075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 09/10/2020] [Indexed: 11/20/2022] Open
Abstract
Background Human embryonic stem cells (hESC) have been an invaluable research tool to study motor neuron development and disorders. However, transcriptional regulation of multiple temporal stages from ESCs to spinal motor neurons (MNs) has not yet been fully elucidated. Thus, the goals of this study were to profile the time-course expression patterns of lncRNAs during MN differentiation of ESCs and to clarify the potential mechanisms of the lncRNAs that are related to MN differentiation. Methods We utilized our previous protocol which can harvest motor neuron in more than 90% purity from hESCs. Then, differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) during MN differentiation were identified through RNA sequencing. Bioinformatic analyses were performed to assess potential biological functions of genes. We also performed qRT-PCR to validate the DElncRNAs and DEmRNAs. Results A total of 441 lncRNAs and 1,068 mRNAs at day 6, 443 and 1,175 at day 12, and 338 lncRNAs and 68 mRNAs at day 18 were differentially expressed compared with day 0. Bioinformatic analyses identified that several key regulatory genes including POU5F1, TDGF1, SOX17, LEFTY2 and ZSCAN10, which involved in the regulation of embryonic development. We also predicted 283 target genes of DElncRNAs, in which 6 mRNAs were differentially expressed. Significant fold changes in lncRNAs (NCAM1-AS) and mRNAs (HOXA3) were confirmed by qRT-PCR. Then, through predicted overlapped miRNA verification, we constructed a lncRNA NCAM1-AS-miRNA-HOXA3 network.
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Affiliation(s)
- Xue-Jiao Sun
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ming-Xing Li
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chen-Zi Gong
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Chen
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mohammad Nasb
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sayed Zulfiqar Ali Shah
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Muhammad Rehan
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Jie Li
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Chen
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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17
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Bulajić M, Srivastava D, Dasen JS, Wichterle H, Mahony S, Mazzoni EO. Differential abilities to engage inaccessible chromatin diversify vertebrate Hox binding patterns. Development 2020; 147:dev194761. [PMID: 33028607 PMCID: PMC7710020 DOI: 10.1242/dev.194761] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/25/2020] [Indexed: 12/17/2022]
Abstract
Although Hox genes encode for conserved transcription factors (TFs), they are further divided into anterior, central and posterior groups based on their DNA-binding domain similarity. The posterior Hox group expanded in the deuterostome clade and patterns caudal and distal structures. We aimed to address how similar Hox TFs diverge to induce different positional identities. We studied Hox TF DNA-binding and regulatory activity during an in vitro motor neuron differentiation system that recapitulates embryonic development. We found diversity in the genomic binding profiles of different Hox TFs, even among the posterior group paralogs that share similar DNA-binding domains. These differences in genomic binding were explained by differing abilities to bind to previously inaccessible sites. For example, the posterior group HOXC9 had a greater ability to bind occluded sites than the posterior HOXC10, producing different binding patterns and driving differential gene expression programs. From these results, we propose that the differential abilities of posterior Hox TFs to bind to previously inaccessible chromatin drive patterning diversification.This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Milica Bulajić
- Department of Biology, New York University, New York, NY 10003, USA
| | - Divyanshi Srivastava
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Jeremy S Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA
| | - Hynek Wichterle
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Neuroscience, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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18
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Shin MM, Catela C, Dasen J. Intrinsic control of neuronal diversity and synaptic specificity in a proprioceptive circuit. eLife 2020; 9:56374. [PMID: 32808924 PMCID: PMC7467731 DOI: 10.7554/elife.56374] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
Abstract
Relay of muscle-derived sensory information to the CNS is essential for the execution of motor behavior, but how proprioceptive sensory neurons (pSNs) establish functionally appropriate connections is poorly understood. A prevailing model of sensory-motor circuit assembly is that peripheral, target-derived, cues instruct pSN identities and patterns of intraspinal connectivity. To date no known intrinsic determinants of muscle-specific pSN fates have been described in vertebrates. We show that expression of Hox transcription factors defines pSN subtypes, and these profiles are established independently of limb muscle. The Hoxc8 gene is expressed by pSNs and motor neurons (MNs) targeting distal forelimb muscles, and sensory-specific depletion of Hoxc8 in mice disrupts sensory-motor synaptic matching, without affecting pSN survival or muscle targeting. These results indicate that the diversity and central specificity of pSNs and MNs are regulated by a common set of determinants, thus linking early rostrocaudal patterning to the assembly of limb control circuits.
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Affiliation(s)
- Maggie M Shin
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, United States
| | - Catarina Catela
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Jeremy Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, United States
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19
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Deng J, Ding HH, Long JL, Lin SY, Liu M, Zhang XQ, Xin WJ, Ruan X. Oxaliplatin-induced neuropathic pain involves HOXA6 via a TET1-dependent demethylation of the SOX10 promoter. Int J Cancer 2020; 147:2503-2514. [PMID: 32428246 DOI: 10.1002/ijc.33106] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 03/25/2020] [Accepted: 05/05/2020] [Indexed: 12/21/2022]
Abstract
Chemotherapy-induced neuropathic pain is a common dose-limiting side effect of cancer treatment but the underlying mechanisms are largely unknown. Here, we used a whole-genome expression microarray and gene ontology analysis to identify the upregulation of a sequence-specific DNA-binding protein, HOXA6, in the spinal dorsal horn on Day 10 after injection of rats with oxaliplatin. Genetic disruption of HOXA6 with siRNAs alleviated mechanical allodynia after oxaliplatin administration. Reduced representation bisulfite sequencing assays indicated that oxaliplatin decreased the methylation levels of the SOX10 promoter but not of HOXA6. TET1 was also upregulated by oxaliplatin. Genetic disruption of TET1 with siRNA blocked the promoter demethylation of SOX10 and the upregulation of HOXA6 and SOX10. Importantly, inhibition of SOX10 by intrathecal application of SOX10 siRNA ameliorated the mechanical allodynia induced by oxaliplatin and downregulated the expression of HOXA6. Consistently, overexpression of SOX10 through intraspinal injection of AAV-SOX10-EGFP produced mechanical allodynia and upregulated the expression of spinal dorsal horn HOXA6. Moreover, chromatin immunoprecipitation assays demonstrated that oxaliplatin increased the binding of SOX10 to the promoter region of HOXA6. Taken together, our data suggest that HOXA6 upregulation through the TET1-mediated promoter demethylation of SOX10 may contribute to oxaliplatin-induced neuropathic pain.
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Affiliation(s)
- Jie Deng
- Department of Anesthesia and Pain Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Huan-Huan Ding
- Guangdong Province Key Laboratory of Brain Function and Disease, Department of physiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Jia-Li Long
- Department of Pathology, the Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, China
| | - Su-Yan Lin
- Guangdong Province Key Laboratory of Brain Function and Disease, Department of physiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Meng Liu
- Guangdong Province Key Laboratory of Brain Function and Disease, Department of physiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xue-Qin Zhang
- The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, China
| | - Wen-Jun Xin
- Guangdong Province Key Laboratory of Brain Function and Disease, Department of physiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xiangcai Ruan
- Department of Anesthesia and Pain Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.,Department of Anesthesia and Pain Medicine, Second Affiliated Hospital of South China University of Technology, Guangzhou, China
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20
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Sagner A, Briscoe J. Establishing neuronal diversity in the spinal cord: a time and a place. Development 2019; 146:146/22/dev182154. [DOI: 10.1242/dev.182154] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
ABSTRACT
The vertebrate spinal cord comprises multiple functionally distinct neuronal cell types arranged in characteristic positions. During development, these different types of neurons differentiate from transcriptionally distinct neural progenitors that are arrayed in discrete domains along the dorsal-ventral and anterior-posterior axes of the embryonic spinal cord. This organization arises in response to morphogen gradients acting upstream of a gene regulatory network, the architecture of which determines the spatial and temporal pattern of gene expression. In recent years, substantial progress has been made in deciphering the regulatory network that underlies the specification of distinct progenitor and neuronal cell identities. In this Review, we outline how distinct neuronal cell identities are established in response to spatial and temporal patterning systems, and outline novel experimental approaches to study the emergence and function of neuronal diversity in the spinal cord.
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21
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Chen TH, Chen JA. Multifaceted roles of microRNAs: From motor neuron generation in embryos to degeneration in spinal muscular atrophy. eLife 2019; 8:50848. [PMID: 31738166 PMCID: PMC6861003 DOI: 10.7554/elife.50848] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/05/2019] [Indexed: 12/12/2022] Open
Abstract
Two crucial questions in neuroscience are how neurons establish individual identity in the developing nervous system and why only specific neuron subtypes are vulnerable to neurodegenerative diseases. In the central nervous system, spinal motor neurons serve as one of the best-characterized cell types for addressing these two questions. In this review, we dissect these questions by evaluating the emerging role of regulatory microRNAs in motor neuron generation in developing embryos and their potential contributions to neurodegenerative diseases such as spinal muscular atrophy (SMA). Given recent promising results from novel microRNA-based medicines, we discuss the potential applications of microRNAs for clinical assessments of SMA disease progression and treatment.
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Affiliation(s)
- Tai-Heng Chen
- PhD Program in Translational Medicine, Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Academia Sinica, Kaohsiung, Taiwan.,Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jun-An Chen
- PhD Program in Translational Medicine, Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Academia Sinica, Kaohsiung, Taiwan.,Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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22
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Turner N, Mikalauskaite D, Barone K, Flaherty K, Senevirathne G, Adachi N, Shubin NH, Nakamura T. The evolutionary origins and diversity of the neuromuscular system of paired appendages in batoids. Proc Biol Sci 2019; 286:20191571. [PMID: 31662089 DOI: 10.1098/rspb.2019.1571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Appendage patterning and evolution have been active areas of inquiry for the past two centuries. While most work has centred on the skeleton, particularly that of amniotes, the evolutionary origins and molecular underpinnings of the neuromuscular diversity of fish appendages have remained enigmatic. The fundamental pattern of segmentation in amniotes, for example, is that all muscle precursors and spinal nerves enter either the paired appendages or body wall at the same spinal level. The condition in finned vertebrates is not understood. To address this gap in knowledge, we investigated the development of muscles and nerves in unpaired and paired fins of skates and compared them to those of chain catsharks. During skate and shark embryogenesis, cell populations of muscle precursors and associated spinal nerves at the same axial level contribute to both appendages and body wall, perhaps representing an ancestral condition of gnathostome appendicular neuromuscular systems. Remarkably in skates, this neuromuscular bifurcation as well as colinear Hox expression extend posteriorly to pattern a broad paired fin domain. In addition, we identified migratory muscle precursors (MMPs), which are known to develop into paired appendage muscles with Pax3 and Lbx1 gene expression, in the dorsal fins of skates. Our results suggest that muscles of paired fins have evolved via redeployment of the genetic programme of MMPs that were already involved in dorsal fin development. Appendicular neuromuscular systems most likely have emerged as side branches of body wall neuromusculature and have been modified to adapt to distinct aquatic and terrestrial habitats.
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Affiliation(s)
- Natalie Turner
- Department of Genetics, The State University of New Jersey, Piscataway, NJ 08854, USA
| | | | - Krista Barone
- Department of Genetics, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Kathleen Flaherty
- Comparative Medicine Resources, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Gayani Senevirathne
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Noritaka Adachi
- Aix-Marseille Université, IBDM, CNRS UMR 7288, Marseille, France
| | - Neil H Shubin
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Tetsuya Nakamura
- Department of Genetics, The State University of New Jersey, Piscataway, NJ 08854, USA
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23
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Catela C, Kratsios P. Transcriptional mechanisms of motor neuron development in vertebrates and invertebrates. Dev Biol 2019; 475:193-204. [PMID: 31479648 DOI: 10.1016/j.ydbio.2019.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 07/08/2019] [Accepted: 08/29/2019] [Indexed: 02/04/2023]
Abstract
Across phylogeny, motor neurons (MNs) represent a single but often remarkably diverse neuronal class composed of a multitude of subtypes required for vital behaviors, such as eating and locomotion. Over the past decades, seminal studies in multiple model organisms have advanced our molecular understanding of the early steps of MN development, such as progenitor specification and acquisition of MN subtype identity, by revealing key roles for several evolutionarily conserved transcription factors. However, very little is known about the molecular strategies that allow distinct MN subtypes to maintain their identity- and function-defining features during the late steps of development and postnatal life. Here, we provide an overview of invertebrate and vertebrate studies on transcription factor-based strategies that control early and late steps of MN development, aiming to highlight evolutionarily conserved gene regulatory principles necessary for establishment and maintenance of neuronal identity.
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Affiliation(s)
- Catarina Catela
- Department of Neurobiology, University of Chicago, Chicago, IL, 60637, USA; The Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL, USA
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL, 60637, USA; The Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL, USA.
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24
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Farrag M, Leipzig ND. Subcutaneous Maturation of Neural Stem Cell-Loaded Hydrogels Forms Region-Specific Neuroepithelium. Cells 2018; 7:cells7100173. [PMID: 30336590 PMCID: PMC6210402 DOI: 10.3390/cells7100173] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 10/09/2018] [Accepted: 10/11/2018] [Indexed: 01/14/2023] Open
Abstract
A combinatorial approach integrating stem cells and capable of exploiting available cues is likely needed to regenerate lost neural tissues and ultimately restore neurologic functions. This study investigates the effects of the subcutaneous maturation of adult-derived neural stem cell (aNSCs) seeded into biomaterial constructs on aNSC differentiation and ultimate regional neuronal identity as a first step toward a future spinal cord injury treatment. To achieve this, we encapsulated rat aNSCs in chitosan-based hydrogels functionalized with immobilized azide-tagged interferon-γ inside a chitosan conduit. Then, we implanted these constructs in the subcutaneous tissues in the backs of rats in the cervical, thoracic, and lumbar regions for 4, 6, and 8 weeks. After harvesting the scaffolds, we analyzed cell differentiation qualitatively using immunohistochemical analysis and quantitatively using RT-qPCR. Results revealed that the hydrogels supported aNSC survival and differentiation up to 4 weeks in the subcutaneous environment as marked by the expression of several neurogenesis markers. Most interesting, the aNSCs expressed region-specific Hox genes corresponding to their region of implantation. This study lays the groundwork for further translational work to recapitulate the potentially undiscovered patterning cues in the subcutaneous tissue and provide support for the conceptual premise that our bioengineering approach can form caudalized region-specific neuroepithelium.
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Affiliation(s)
- Mahmoud Farrag
- Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA.
| | - Nic D Leipzig
- Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA.
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA.
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25
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Yen YP, Hsieh WF, Tsai YY, Lu YL, Liau ES, Hsu HC, Chen YC, Liu TC, Chang M, Li J, Lin SP, Hung JH, Chen JA. Dlk1-Dio3 locus-derived lncRNAs perpetuate postmitotic motor neuron cell fate and subtype identity. eLife 2018; 7:38080. [PMID: 30311912 PMCID: PMC6221546 DOI: 10.7554/elife.38080] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 10/11/2018] [Indexed: 12/28/2022] Open
Abstract
The mammalian imprinted Dlk1-Dio3 locus produces multiple long non-coding RNAs (lncRNAs) from the maternally inherited allele, including Meg3 (i.e., Gtl2) in the mammalian genome. Although this locus has well-characterized functions in stem cell and tumor contexts, its role during neural development is unknown. By profiling cell types at each stage of embryonic stem cell-derived motor neurons (ESC~MNs) that recapitulate spinal cord development, we uncovered that lncRNAs expressed from the Dlk1-Dio3 locus are predominantly and gradually enriched in rostral motor neurons (MNs). Mechanistically, Meg3 and other Dlk1-Dio3 locus-derived lncRNAs facilitate Ezh2/Jarid2 interactions. Loss of these lncRNAs compromises the H3K27me3 landscape, leading to aberrant expression of progenitor and caudal Hox genes in postmitotic MNs. Our data thus illustrate that these lncRNAs in the Dlk1-Dio3 locus, particularly Meg3, play a critical role in maintaining postmitotic MN cell fate by repressing progenitor genes and they shape MN subtype identity by regulating Hox genes. When a gene is active, its DNA sequence is ‘transcribed’ to form a molecule of RNA. Many of these RNAs act as templates for making proteins. But for some genes, the protein molecules are not their final destinations. Their RNA molecules instead help to control gene activity, which can alter the behaviour or the identity of a cell. For example, experiments performed in individual cells suggest that so-called long non-coding RNAs (or lncRNAs for short) guide how stem cells develop into different types of mature cells. However, it is not clear whether lncRNAs play the same critical role in embryos. Yen et al. used embryonic stem cells to model how motor neurons develop in the spinal cord of mouse embryos. This revealed that motor neurons produce large amounts of a specific group of lncRNAs, particularly one called Meg3. Further experiments showed that motor neurons in mouse embryos that lack Meg3 do not correctly silence a set of genes called the Hox genes, which are crucial for laying out the body plans of many different animal embryos. These neurons also incorrectly continue to express genes that are normally active in an early phase of the stem-like cells that make motor neurons. There is wide interest in how lncRNAs help to regulate embryonic development. With this new knowledge of how Meg3 regulates the activity of Hox genes in motor neurons, research could now be directed toward investigating whether lncRNAs help other tissues to develop in a similar way.
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Affiliation(s)
- Ya-Ping Yen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China.,Institute of Biotechnology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Wen-Fu Hsieh
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Ya-Yin Tsai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Ya-Lin Lu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Ee Shan Liau
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Ho-Chiang Hsu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Yen-Chung Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Ting-Chun Liu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Mien Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Joye Li
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Shau-Ping Lin
- Institute of Biotechnology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Jui-Hung Hung
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China.,Department of Computer Science, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Jun-An Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
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26
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Saurin AJ, Delfini MC, Maurel-Zaffran C, Graba Y. The Generic Facet of Hox Protein Function. Trends Genet 2018; 34:941-953. [PMID: 30241969 DOI: 10.1016/j.tig.2018.08.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/07/2018] [Accepted: 08/21/2018] [Indexed: 11/16/2022]
Abstract
Hox transcription factors are essential to promote morphological diversification of the animal body. A substantial number of studies have focused on how Hox proteins reach functional specificity, an issue that arises from the fact that these transcription factors control distinct developmental functions despite sharing similar molecular properties. In this review, we highlight that, besides specific functions, for which these transcription factors are renowned, Hox proteins also often have nonspecific functions. We next discuss some emerging principles of these generic functions and how they relate to specific functions and explore our current grasp of the underlying molecular mechanisms.
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Affiliation(s)
- Andrew J Saurin
- Aix Marseille Univ, CNRS, IBDM, Marseille, France; http://www.ibdm.univ-mrs.fr/equipe/mechanisms-of-gene-regulation-by-transcription-factors/.
| | - Marie Claire Delfini
- Aix Marseille Univ, CNRS, IBDM, Marseille, France; http://www.ibdm.univ-mrs.fr/equipe/mechanisms-of-gene-regulation-by-transcription-factors/
| | - Corinne Maurel-Zaffran
- Aix Marseille Univ, CNRS, IBDM, Marseille, France; http://www.ibdm.univ-mrs.fr/equipe/mechanisms-of-gene-regulation-by-transcription-factors/
| | - Yacine Graba
- Aix Marseille Univ, CNRS, IBDM, Marseille, France; http://www.ibdm.univ-mrs.fr/equipe/mechanisms-of-gene-regulation-by-transcription-factors/.
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27
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Guidance of motor axons: where do we stand? CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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28
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D'Elia KP, Dasen JS. Development, functional organization, and evolution of vertebrate axial motor circuits. Neural Dev 2018; 13:10. [PMID: 29855378 PMCID: PMC5984435 DOI: 10.1186/s13064-018-0108-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/26/2018] [Indexed: 12/20/2022] Open
Abstract
Neuronal control of muscles associated with the central body axis is an ancient and essential function of the nervous systems of most animal species. Throughout the course of vertebrate evolution, motor circuits dedicated to control of axial muscle have undergone significant changes in their roles within the motor system. In most fish species, axial circuits are critical for coordinating muscle activation sequences essential for locomotion and play important roles in postural correction. In tetrapods, axial circuits have evolved unique functions essential to terrestrial life, including maintaining spinal alignment and breathing. Despite the diverse roles of axial neural circuits in motor behaviors, the genetic programs underlying their assembly are poorly understood. In this review, we describe recent studies that have shed light on the development of axial motor circuits and compare and contrast the strategies used to wire these neural networks in aquatic and terrestrial vertebrate species.
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Affiliation(s)
- Kristen P D'Elia
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, 10016, USA
| | - Jeremy S Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, 10016, USA.
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29
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Jung H, Baek M, D'Elia KP, Boisvert C, Currie PD, Tay BH, Venkatesh B, Brown SM, Heguy A, Schoppik D, Dasen JS. The Ancient Origins of Neural Substrates for Land Walking. Cell 2018; 172:667-682.e15. [PMID: 29425489 PMCID: PMC5808577 DOI: 10.1016/j.cell.2018.01.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/18/2017] [Accepted: 01/05/2018] [Indexed: 01/30/2023]
Abstract
Walking is the predominant locomotor behavior expressed by land-dwelling vertebrates, but it is unknown when the neural circuits that are essential for limb control first appeared. Certain fish species display walking-like behaviors, raising the possibility that the underlying circuitry originated in primitive marine vertebrates. We show that the neural substrates of bipedalism are present in the little skate Leucoraja erinacea, whose common ancestor with tetrapods existed ∼420 million years ago. Leucoraja exhibits core features of tetrapod locomotor gaits, including left-right alternation and reciprocal extension-flexion of the pelvic fins. Leucoraja also deploys a remarkably conserved Hox transcription factor-dependent program that is essential for selective innervation of fin/limb muscle. This network encodes peripheral connectivity modules that are distinct from those used in axial muscle-based swimming and has apparently been diminished in most modern fish. These findings indicate that the circuits that are essential for walking evolved through adaptation of a genetic regulatory network shared by all vertebrates with paired appendages. VIDEO ABSTRACT.
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Affiliation(s)
- Heekyung Jung
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Myungin Baek
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Kristen P D'Elia
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Catherine Boisvert
- Department of Environment and Agriculture, Curtin University, Bentley, WA 6102, Australia; Australian Regenerative Medicine Institute (ARMI), Monash University, Clayton, VIC 3800, Australia
| | - Peter D Currie
- Australian Regenerative Medicine Institute (ARMI), Monash University, Clayton, VIC 3800, Australia; EMBL Australia, Melbourne Node, Monash University, Clayton, VIC 3800, Australia
| | - Boon-Hui Tay
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Biopolis, Singapore 138673, Singapore
| | - Byrappa Venkatesh
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Biopolis, Singapore 138673, Singapore; Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Stuart M Brown
- Applied Bioinformatics Laboratory, NYU School of Medicine, New York, NY 10016, USA
| | - Adriana Heguy
- Genome Technology Center, Division for Advanced Research Technologies, and Department of Pathology, NYU School of Medicine, New York, NY 10016, USA
| | - David Schoppik
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA; Department of Otolaryngology, NYU School of Medicine, New York, NY 10016, USA
| | - Jeremy S Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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30
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Sweeney LB, Bikoff JB, Gabitto MI, Brenner-Morton S, Baek M, Yang JH, Tabak EG, Dasen JS, Kintner CR, Jessell TM. Origin and Segmental Diversity of Spinal Inhibitory Interneurons. Neuron 2018; 97:341-355.e3. [PMID: 29307712 PMCID: PMC5880537 DOI: 10.1016/j.neuron.2017.12.029] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/14/2017] [Accepted: 12/17/2017] [Indexed: 10/18/2022]
Abstract
Motor output varies along the rostro-caudal axis of the tetrapod spinal cord. At limb levels, ∼60 motor pools control the alternation of flexor and extensor muscles about each joint, whereas at thoracic levels as few as 10 motor pools supply muscle groups that support posture, inspiration, and expiration. Whether such differences in motor neuron identity and muscle number are associated with segmental distinctions in interneuron diversity has not been resolved. We show that select combinations of nineteen transcription factors that specify lumbar V1 inhibitory interneurons generate subpopulations enriched at limb and thoracic levels. Specification of limb and thoracic V1 interneurons involves the Hox gene Hoxc9 independently of motor neurons. Thus, early Hox patterning of the spinal cord determines the identity of V1 interneurons and motor neurons. These studies reveal a developmental program of V1 interneuron diversity, providing insight into the organization of inhibitory interneurons associated with differential motor output.
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Affiliation(s)
- Lora B Sweeney
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Jay B Bikoff
- Howard Hughes Medical Institute, Zuckerman Institute, Departments of Neuroscience, and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Mariano I Gabitto
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY 10010, USA.
| | - Susan Brenner-Morton
- Howard Hughes Medical Institute, Zuckerman Institute, Departments of Neuroscience, and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Myungin Baek
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Jerry H Yang
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Esteban G Tabak
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
| | - Jeremy S Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Christopher R Kintner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Thomas M Jessell
- Howard Hughes Medical Institute, Zuckerman Institute, Departments of Neuroscience, and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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31
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Hirasawa T, Kuratani S. Evolution of the muscular system in tetrapod limbs. ZOOLOGICAL LETTERS 2018; 4:27. [PMID: 30258652 PMCID: PMC6148784 DOI: 10.1186/s40851-018-0110-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/04/2018] [Indexed: 05/16/2023]
Abstract
While skeletal evolution has been extensively studied, the evolution of limb muscles and brachial plexus has received less attention. In this review, we focus on the tempo and mode of evolution of forelimb muscles in the vertebrate history, and on the developmental mechanisms that have affected the evolution of their morphology. Tetrapod limb muscles develop from diffuse migrating cells derived from dermomyotomes, and the limb-innervating nerves lose their segmental patterns to form the brachial plexus distally. Despite such seemingly disorganized developmental processes, limb muscle homology has been highly conserved in tetrapod evolution, with the apparent exception of the mammalian diaphragm. The limb mesenchyme of lateral plate mesoderm likely plays a pivotal role in the subdivision of the myogenic cell population into individual muscles through the formation of interstitial muscle connective tissues. Interactions with tendons and motoneuron axons are involved in the early and late phases of limb muscle morphogenesis, respectively. The mechanism underlying the recurrent generation of limb muscle homology likely resides in these developmental processes, which should be studied from an evolutionary perspective in the future.
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Affiliation(s)
- Tatsuya Hirasawa
- Laboratory for Evolutionary Morphology, RIKEN Center for Biosystems Dynamics Research (BDR), 2-2-3 Minatojima-minami, Chuo-ku, Kobe, Hyogo 650-0047 Japan
| | - Shigeru Kuratani
- Laboratory for Evolutionary Morphology, RIKEN Center for Biosystems Dynamics Research (BDR), 2-2-3 Minatojima-minami, Chuo-ku, Kobe, Hyogo 650-0047 Japan
- Evolutionary Morphology Laboratory, RIKEN Cluster for Pioneering Research (CPR), 2-2-3 Minatojima-minami, Chuo-ku, Kobe, Hyogo 650-0047 Japan
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32
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Narendra V, Bulajić M, Dekker J, Mazzoni EO, Reinberg D. CTCF-mediated topological boundaries during development foster appropriate gene regulation. Genes Dev 2017; 30:2657-2662. [PMID: 28087711 PMCID: PMC5238725 DOI: 10.1101/gad.288324.116] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 12/12/2016] [Indexed: 12/11/2022]
Abstract
The genome is organized into repeating topologically associated domains (TADs), each of which is spatially isolated from its neighbor by poorly understood boundary elements thought to be conserved across cell types. Here, we show that deletion of CTCF (CCCTC-binding factor)-binding sites at TAD and sub-TAD topological boundaries that form within the HoxA and HoxC clusters during differentiation not only disturbs local chromatin domain organization and regulatory interactions but also results in homeotic transformations typical of Hox gene misregulation. Moreover, our data suggest that CTCF-dependent boundary function can be modulated by competing forces, such as the self-assembly of polycomb domains within the nucleus. Therefore, CTCF boundaries are not merely static structural components of the genome but instead are locally dynamic regulatory structures that control gene expression during development.
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Affiliation(s)
- Varun Narendra
- Howard Hughes Medical Institute, New York, New York 10016, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
| | - Milica Bulajić
- Department of Biology, New York University, New York, New York 10003, USA
| | - Job Dekker
- Howard Hughes Medical Institute, New York, New York 10016, USA.,Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Esteban O Mazzoni
- Department of Biology, New York University, New York, New York 10003, USA
| | - Danny Reinberg
- Howard Hughes Medical Institute, New York, New York 10016, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
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33
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MicroRNA filters Hox temporal transcription noise to confer boundary formation in the spinal cord. Nat Commun 2017; 8:14685. [PMID: 28337978 PMCID: PMC5376671 DOI: 10.1038/ncomms14685] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 01/24/2017] [Indexed: 01/17/2023] Open
Abstract
The initial rostrocaudal patterning of the neural tube leads to differential expression of Hox genes that contribute to the specification of motor neuron (MN) subtype identity. Although several 3' Hox mRNAs are expressed in progenitors in a noisy manner, these Hox proteins are not expressed in the progenitors and only become detectable in postmitotic MNs. MicroRNA biogenesis impairment leads to precocious expression and propagates the noise of Hoxa5 at the protein level, resulting in an imprecise Hoxa5-Hoxc8 boundary. Here we uncover, using in silico simulation, two feed-forward Hox-miRNA loops accounting for the precocious and noisy Hoxa5 expression, as well as an ill-defined boundary phenotype in Dicer mutants. Finally, we identify mir-27 as a major regulator coordinating the temporal delay and spatial boundary of Hox protein expression. Our results provide a novel trans Hox-miRNA circuit filtering transcription noise and controlling the timing of protein expression to confer robust individual MN identity.
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34
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Divergent Hox Coding and Evasion of Retinoid Signaling Specifies Motor Neurons Innervating Digit Muscles. Neuron 2017; 93:792-805.e4. [PMID: 28190640 DOI: 10.1016/j.neuron.2017.01.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/13/2016] [Accepted: 01/20/2017] [Indexed: 11/21/2022]
Abstract
The establishment of spinal motor neuron subclass diversity is achieved through developmental programs that are aligned with the organization of muscle targets in the limb. The evolutionary emergence of digits represents a specialized adaptation of limb morphology, yet it remains unclear how the specification of digit-innervating motor neuron subtypes parallels the elaboration of digits. We show that digit-innervating motor neurons can be defined by selective gene markers and distinguished from other LMC neurons by the expression of a variant Hox gene repertoire and by the failure to express a key enzyme involved in retinoic acid synthesis. This divergent developmental program is sufficient to induce the specification of digit-innervating motor neurons, emphasizing the specialized status of digit control in the evolution of skilled motor behaviors. Our findings suggest that the emergence of digits in the limb is matched by distinct mechanisms for specifying motor neurons that innervate digit muscles.
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35
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Hessinger C, Technau GM, Rogulja-Ortmann A. The Drosophila Hox gene Ultrabithorax acts in both muscles and motoneurons to orchestrate formation of specific neuromuscular connections. Development 2016; 144:139-150. [PMID: 27913640 PMCID: PMC5278631 DOI: 10.1242/dev.143875] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/17/2016] [Indexed: 12/29/2022]
Abstract
Hox genes are known to specify motoneuron pools in the developing vertebrate spinal cord and to control motoneuronal targeting in several species. However, the mechanisms controlling axial diversification of muscle innervation patterns are still largely unknown. We present data showing that the Drosophila Hox gene Ultrabithorax (Ubx) acts in the late embryo to establish target specificity of ventrally projecting RP motoneurons. In abdominal segments A2 to A7, RP motoneurons innervate the ventrolateral muscles VL1-4, with VL1 and VL2 being innervated in a Wnt4-dependent manner. In Ubx mutants, these motoneurons fail to make correct contacts with muscle VL1, a phenotype partially resembling that of the Wnt4 mutant. We show that Ubx regulates expression of Wnt4 in muscle VL2 and that it interacts with the Wnt4 response pathway in the respective motoneurons. Ubx thus orchestrates the interaction between two cell types, muscles and motoneurons, to regulate establishment of the ventrolateral neuromuscular network. Summary: Ultrabithorax controls correct innervation of ventrolateral muscles by coordinating Wnt4 ligand expression in muscles with the signalling pathway response in motoneurons.
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36
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Hanley O, Zewdu R, Cohen LJ, Jung H, Lacombe J, Philippidou P, Lee DH, Selleri L, Dasen JS. Parallel Pbx-Dependent Pathways Govern the Coalescence and Fate of Motor Columns. Neuron 2016; 91:1005-1020. [PMID: 27568519 DOI: 10.1016/j.neuron.2016.07.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/20/2016] [Accepted: 07/14/2016] [Indexed: 01/08/2023]
Abstract
The clustering of neurons sharing similar functional properties and connectivity is a common organizational feature of vertebrate nervous systems. Within motor networks, spinal motor neurons (MNs) segregate into longitudinally arrayed subtypes, establishing a central somatotopic map of peripheral target innervation. MN organization and connectivity relies on Hox transcription factors expressed along the rostrocaudal axis; however, the developmental mechanisms governing the orderly arrangement of MNs are largely unknown. We show that Pbx genes, which encode Hox cofactors, are essential for the segregation and clustering of neurons within motor columns. In the absence of Pbx1 and Pbx3 function, Hox-dependent programs are lost and the remaining MN subtypes are unclustered and disordered. Identification of Pbx gene targets revealed an unexpected and apparently Hox-independent role in defining molecular features of dorsally projecting medial motor column (MMC) neurons. These results indicate Pbx genes act in parallel genetic pathways to orchestrate neuronal subtype differentiation, connectivity, and organization.
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Affiliation(s)
- Olivia Hanley
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Rediet Zewdu
- Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Lisa J Cohen
- Genome Technology Center, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016, USA
| | - Heekyung Jung
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Julie Lacombe
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Polyxeni Philippidou
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - David H Lee
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Licia Selleri
- Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Jeremy S Dasen
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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37
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Leijnse JN, D'Herde K. Revisiting the segmental organization of the human spinal cord. J Anat 2016; 229:384-93. [PMID: 27173936 DOI: 10.1111/joa.12493] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2016] [Indexed: 11/30/2022] Open
Abstract
In classic anatomic atlases, the spinal cord is standardly represented in its anatomical form with symmetrically emerging anterior and posterior roots, which at the level of the intervertebral foramen combine into the spinal nerves. The parts of the cord delimited by the boundaries of the roots are called segments or myelomeres. Associated with their regular repetitive appearance is the notion that the cord is segmentally organized. This segmental view is reinforced by clinical practice. Spinal cord roots innervate specific body parts. The level of cord trauma is diagnosed by the de-innervation symptoms of these parts. However, systemically, the case for a segmentally organized cord is not so clear. To date, developmental and genetic research points to a regionally rather than a segmentally organized cord. In the present study, to what degree the fila radicularia are segmentally implanted along the cord was investigated. The research hypothesis was that if the fila radicularia were non-segmentally implanted at the cord surface, it would be unlikely that the internal neuron stratum would be segmented. The visual segmented aspect of the myelomeres would then be the consequence of the necessary bundling of axons towards the vertebral foramen as the only exits of the vertebral canal, rather than of an underlying segment organization of the cord itself. To investigate the research hypothesis, the fila radicularia in the cervical-upper thoracic part of five spinal cords were detached from their spinal nerves and dissected in detail. The principal research question was if the fila radicularia are separated from their spinal nerves and dissected from their connective tissues up to the cord, would it be possible to reconstruct the original spinal segments from the morphology and interspaces of the fila? The dissections revealed that the anterior fila radicularia emerge from the cord at regular regionally modulated interspaces without systematic segmental delineations. The posterior fila radicularia are somewhat more segmentally implanted, but the pattern is individually inconsistent. The posterior and anterior roots have notable morphological differences, and hypotheses are presented to help explain these. The macroscopic observations are consistent with a regionally but not a segmentally organized cord. This conclusion was visually summarized in photographs of spinal cords with ipsilateral intact roots and contralateral individually dissected fila radicularia. It was suggested that this dual view of the spinal cord be added to the standard anatomic textbooks to counterbalance the current possibly biased view of a segmented cord.
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Affiliation(s)
- J N Leijnse
- Department of Anatomy and Embryology, University of Ghent, Ghent, Belgium
| | - K D'Herde
- Department of Anatomy and Embryology, University of Ghent, Ghent, Belgium
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38
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Catela C, Shin MM, Lee DH, Liu JP, Dasen JS. Hox Proteins Coordinate Motor Neuron Differentiation and Connectivity Programs through Ret/Gfrα Genes. Cell Rep 2016; 14:1901-15. [PMID: 26904955 DOI: 10.1016/j.celrep.2016.01.067] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/07/2015] [Accepted: 01/21/2016] [Indexed: 11/25/2022] Open
Abstract
The accuracy of neural circuit assembly relies on the precise spatial and temporal control of synaptic specificity determinants during development. Hox transcription factors govern key aspects of motor neuron (MN) differentiation; however, the terminal effectors of their actions are largely unknown. We show that Hox/Hox cofactor interactions coordinate MN subtype diversification and connectivity through Ret/Gfrα receptor genes. Hox and Meis proteins determine the levels of Ret in MNs and define the intrasegmental profiles of Gfrα1 and Gfrα3 expression. Loss of Ret or Gfrα3 leads to MN specification and innervation defects similar to those observed in Hox mutants, while expression of Ret and Gfrα1 can bypass the requirement for Hox genes during MN pool differentiation. These studies indicate that Hox proteins contribute to neuronal fate and muscle connectivity through controlling the levels and pattern of cell surface receptor expression, consequently gating the ability of MNs to respond to limb-derived instructive cues.
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Affiliation(s)
- Catarina Catela
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Maggie M Shin
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - David H Lee
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Jeh-Ping Liu
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jeremy S Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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39
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Zheng C, Diaz-Cuadros M, Chalfie M. Hox Genes Promote Neuronal Subtype Diversification through Posterior Induction in Caenorhabditis elegans. Neuron 2016; 88:514-27. [PMID: 26539892 DOI: 10.1016/j.neuron.2015.09.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/05/2015] [Accepted: 09/19/2015] [Indexed: 10/22/2022]
Abstract
Although Hox genes specify the differentiation of neuronal subtypes along the anterior-posterior axis, their mode of action is not entirely understood. Using two subtypes of the touch receptor neurons (TRNs) in C. elegans, we found that a "posterior induction" mechanism underlies the Hox control of terminal neuronal differentiation. The anterior subtype maintains a default TRN state, whereas the posterior subtype undergoes further morphological and transcriptional specification induced by the posterior Hox proteins, mainly EGL-5/Abd-B. Misexpression of the posterior Hox proteins transformed the anterior TRN subtype toward a posterior identity both morphologically and genetically. The specification of the posterior subtype requires EGL-5-induced repression of TALE cofactors, which antagonize EGL-5 functions, and the activation of rfip-1, a component of recycling endosomes, which mediates Hox activities by promoting subtype-specific neurite outgrowth. Finally, EGL-5 is required for subtype-specific circuit formation by acting in both the sensory neuron and downstream interneuron to promote functional connectivity.
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Affiliation(s)
- Chaogu Zheng
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | | | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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40
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Rezsohazy R, Saurin AJ, Maurel-Zaffran C, Graba Y. Cellular and molecular insights into Hox protein action. Development 2016; 142:1212-27. [PMID: 25804734 DOI: 10.1242/dev.109785] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hox genes encode homeodomain transcription factors that control morphogenesis and have established functions in development and evolution. Hox proteins have remained enigmatic with regard to the molecular mechanisms that endow them with specific and diverse functions, and to the cellular functions that they control. Here, we review recent examples of Hox-controlled cellular functions that highlight their versatile and highly context-dependent activity. This provides the setting to discuss how Hox proteins control morphogenesis and organogenesis. We then summarise the molecular modalities underlying Hox protein function, in particular in light of current models of transcription factor function. Finally, we discuss how functional divergence between Hox proteins might be achieved to give rise to the many facets of their action.
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Affiliation(s)
- René Rezsohazy
- Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve B-1348, Belgium
| | - Andrew J Saurin
- Aix Marseille Université, CNRS, IBDM, UMR 7288, Marseille 13288, Cedex 09, France
| | | | - Yacine Graba
- Aix Marseille Université, CNRS, IBDM, UMR 7288, Marseille 13288, Cedex 09, France
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41
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Abstract
Transcription factors control neuronal differentiation by acting as "terminal selectors" that determine the specific cell fates of different types of neurons. The specification of cell fate, however, requires high fidelity, which relies on stable and robust expression of the terminal selectors. Our recent studies in C. elegans suggest that a second set of transcription factors function as reinforcing or protecting factors to stabilize the expression and activity of terminal selectors. Some serve as "guarantors" to ensure the activation and continuous expression of the selectors by reducing stochastic fluctuations in gene expression; others safeguard the protein function of selectors by repressing inhibitors that would block their activity. These transcription factors, unlike the terminal selectors, do not induce specification but secure neuronal cell fate and provide reliability in differentiation.
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42
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Zheng C, Jin FQ, Chalfie M. Hox Proteins Act as Transcriptional Guarantors to Ensure Terminal Differentiation. Cell Rep 2015; 13:1343-1352. [PMID: 26547238 DOI: 10.1016/j.celrep.2015.10.044] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/29/2015] [Accepted: 10/19/2015] [Indexed: 11/18/2022] Open
Abstract
Cell differentiation usually occurs with high fidelity, but the expression of many transcription factors is variable. Using the touch receptor neurons (TRNs) in C. elegans, we found that the Hox proteins CEH-13/lab and EGL-5/Abd-B overcome this variability by facilitating the activation of the common TRN fate determinant mec-3 in the anterior and posterior TRNs, respectively. CEH-13 and EGL-5 increase the probability of mec-3 transcriptional activation by the POU-homeodomain transcription factor UNC-86 using the same Hox/Pbx binding site. Mutation of ceh-13 and egl-5 resulted in an incomplete (∼40%) loss of the TRN fate in respective TRNs, which correlates with quantitative mRNA measurements showing two distinct modes (all or none) of mec-3 transcription. Therefore, Hox proteins act as transcriptional "guarantors" in order to ensure reliable and robust gene expression during terminal neuronal differentiation. Guarantors do not activate gene expression by themselves but promote full activation of target genes regulated by other transcription factors.
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Affiliation(s)
- Chaogu Zheng
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Felix Qiaochu Jin
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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43
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Larsen BM, Hrycaj SM, Newman M, Li Y, Wellik DM. Mesenchymal Hox6 function is required for mouse pancreatic endocrine cell differentiation. Development 2015; 142:3859-68. [PMID: 26450967 DOI: 10.1242/dev.126888] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/30/2015] [Indexed: 12/20/2022]
Abstract
Despite significant advances in our understanding of pancreatic endocrine cell development, the function of the pancreatic mesodermal niche in this process is poorly understood. Here we report a novel role for mouse Hox6 genes in pancreatic organogenesis. Hox6 genes are expressed exclusively in the mesoderm of the developing pancreas. Genetic loss of all three Hox6 paralogs (Hoxa6, Hoxb6 and Hoxc6) leads to a dramatic loss of endoderm-derived endocrine cells, including insulin-secreting β-cells, and to mild delays and disruptions in pancreatic branching and exocrine differentiation. Ngn3-expressing pan-endocrine progenitor cells are specified normally in Hox6 mutant pancreata, but fail to mature into hormone-producing cells. Reduced expression of Wnt5a is observed in mutant pancreatic mesenchyme, leading to subsequent loss of expression of the crucial Wnt inhibitors Sfrp3 and Dkk1 in endocrine progenitor cells. These results reveal a key role for Hox6 genes in establishing Wnt mesenchymal-epithelial crosstalk in pancreatic development.
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Affiliation(s)
- Brian M Larsen
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Steven M Hrycaj
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Micaleah Newman
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ye Li
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Deneen M Wellik
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109-2200, USA Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
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44
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Abstract
Control of movement is a fundamental and complex task of the vertebrate nervous system, which relies on communication between circuits distributed throughout the brain and spinal cord. Many of the networks essential for the execution of basic locomotor behaviors are composed of discrete neuronal populations residing within the spinal cord. The organization and connectivity of these circuits is established through programs that generate functionally diverse neuronal subtypes, each contributing to a specific facet of motor output. Significant progress has been made in deciphering how neuronal subtypes are specified and in delineating the guidance and synaptic specificity determinants at the core of motor circuit assembly. Recent studies have shed light on the basic principles linking locomotor circuit connectivity with function, and they are beginning to reveal how more sophisticated motor behaviors are encoded. In this review, we discuss the impact of developmental programs in specifying motor behaviors governed by spinal circuits.
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Affiliation(s)
- Catarina Catela
- Neuroscience Institute and Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016;
| | - Maggie M Shin
- Neuroscience Institute and Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016;
| | - Jeremy S Dasen
- Neuroscience Institute and Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016;
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45
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Abstract
Evolutionary modifications in nervous systems enabled organisms to adapt to their specific environments and underlie the remarkable diversity of behaviors expressed by animals. Resolving the pathways that shaped and modified neural circuits during evolution remains a significant challenge. Comparative studies have revealed a surprising conservation in the intrinsic signaling systems involved in early patterning of bilaterian nervous systems but also raise the question of how neural circuit compositions and architectures evolved within specific animal lineages. In this review, we discuss the mechanisms that contributed to the emergence and diversity of animal nervous systems, focusing on the circuits governing vertebrate locomotion.
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Affiliation(s)
- Heekyung Jung
- Howard Hughes Medical Institute (HHMI), NYU Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA
| | - Jeremy S Dasen
- Howard Hughes Medical Institute (HHMI), NYU Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA.
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46
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Foxp1-mediated programming of limb-innervating motor neurons from mouse and human embryonic stem cells. Nat Commun 2015; 6:6778. [PMID: 25868900 PMCID: PMC4397664 DOI: 10.1038/ncomms7778] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 02/26/2015] [Indexed: 01/11/2023] Open
Abstract
Spinal motor neurons (MNs) control diverse motor tasks including respiration, posture and locomotion that are disrupted by neurodegenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. Methods directing MN differentiation from stem cells have been developed to enable disease modelling in vitro. However, most protocols produce only a limited subset of endogenous MN subtypes. Here we demonstrate that limb-innervating lateral motor column (LMC) MNs can be efficiently generated from mouse and human embryonic stem cells through manipulation of the transcription factor Foxp1. Foxp1-programmed MNs exhibit features of medial and lateral LMC MNs including expression of specific motor pool markers and axon guidance receptors. Importantly, they preferentially project axons towards limb muscle explants in vitro and distal limb muscles in vivo upon transplantation-hallmarks of bona fide LMC MNs. These results present an effective approach for generating specific MN populations from stem cells for studying MN development and disease.
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47
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Stifani N. Motor neurons and the generation of spinal motor neuron diversity. Front Cell Neurosci 2014; 8:293. [PMID: 25346659 PMCID: PMC4191298 DOI: 10.3389/fncel.2014.00293] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 09/02/2014] [Indexed: 11/13/2022] Open
Abstract
Motor neurons (MNs) are neuronal cells located in the central nervous system (CNS) controlling a variety of downstream targets. This function infers the existence of MN subtypes matching the identity of the targets they innervate. To illustrate the mechanism involved in the generation of cellular diversity and the acquisition of specific identity, this review will focus on spinal MNs (SpMNs) that have been the core of significant work and discoveries during the last decades. SpMNs are responsible for the contraction of effector muscles in the periphery. Humans possess more than 500 different skeletal muscles capable to work in a precise time and space coordination to generate complex movements such as walking or grasping. To ensure such refined coordination, SpMNs must retain the identity of the muscle they innervate. Within the last two decades, scientists around the world have produced considerable efforts to elucidate several critical steps of SpMNs differentiation. During development, SpMNs emerge from dividing progenitor cells located in the medial portion of the ventral neural tube. MN identities are established by patterning cues working in cooperation with intrinsic sets of transcription factors. As the embryo develop, MNs further differentiate in a stepwise manner to form compact anatomical groups termed pools connecting to a unique muscle target. MN pools are not homogeneous and comprise subtypes according to the muscle fibers they innervate. This article aims to provide a global view of MN classification as well as an up-to-date review of the molecular mechanisms involved in the generation of SpMN diversity. Remaining conundrums will be discussed since a complete understanding of those mechanisms constitutes the foundation required for the elaboration of prospective MN regeneration therapies.
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Affiliation(s)
- Nicolas Stifani
- Medical Neuroscience, Dalhousie University Halifax, NS, Canada
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48
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Thevenon J, Monnier N, Callier P, Dieterich K, Francoise M, Montgomery T, Kjaergaard S, Neas K, Dixon J, Dahm TL, Huet F, Ragon C, Mosca-Boidron AL, Marle N, Duplomb L, Aubriot-Lorton MH, Mugneret F, Vokes SA, Tucker HW, Lunardi J, Faivre L, Jouk PS, Thauvin-Robinet C. Delineation of the 3p14.1p13 microdeletion associated with syndromic distal limb contractures. Am J Med Genet A 2014; 164A:3027-34. [PMID: 25258245 DOI: 10.1002/ajmg.a.36751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 08/14/2014] [Indexed: 12/19/2022]
Abstract
Distal limb contractures (DLC) represent a heterogeneous clinical and genetic condition. Overall, 20-25% of the DLC are caused by mutations in genes encoding the muscle contractile apparatus. Large interstitial deletions of the 3p have already been diagnosed by standard chromosomal analysis, but not associated with a specific phenotype. We report on four patients with syndromic DLC presenting with a de novo 3p14.1p13 microdeletion. The clinical features associated multiple contractures, feeding problems, developmental delay, and intellectual disability. Facial dysmorphism was constant with low-set posteriorly rotated ears and blepharophimosis. Review of previously reported cases with a precise mapping of the deletions, documented a 250 kb smallest region of overlap (SRO) necessary for DLC. This region contained one gene, EIF4E3, the first three exons of the FOXP1 gene, and an intronic enhancer of FOXP1 named hs1149. Sanger sequencing and locus quantification of hs1149, EIF4E3, and FOXP1 in a cohort of 11 French patients affected by DLC appeared normal. In conclusion, we delineate a new microdeletion syndrome involving the 3p14.1p13 locus and associated with DLC and severe developmental delay.
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Affiliation(s)
- Julien Thevenon
- Fédération Hospitalo-Universitaire TRANSLAD et Centre de Génétique et Centre de Référence «Anomalies du Développement et Syndromes Malformatifs» du Grand Est, Hôpital d'Enfants, CHU Dijon, Dijon, France; Université de Bourgogne, Dijon, France
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49
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Development of oculomotor circuitry independent of hox3 genes. Nat Commun 2014; 5:4221. [PMID: 24964400 DOI: 10.1038/ncomms5221] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 05/27/2014] [Indexed: 01/05/2023] Open
Abstract
Hox genes have been shown to be essential in vertebrate neural circuit formation and their depletion has resulted in homeotic transformations with neuron loss and miswiring. Here we quantifiy four eye movements in the zebrafish mutant valentino and hox3 knockdowns, and find that contrary to the classical model, oculomotor circuits in hindbrain rhombomeres 5-6 develop and function independently of hox3 genes. All subgroups of oculomotor neurons are present, as well as their input and output connections. Ectopic connections are also established, targeting two specific subsets of horizontal neurons, and the resultant novel eye movements coexists with baseline behaviours. We conclude that the high expression of hox3 genes in rhombomeres 5-6 serves to prevent aberrant neuronal identity and behaviours, but does not appear to be necessary for a comprehensive assembly of functional oculomotor circuits.
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50
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Jung H, Mazzoni EO, Soshnikova N, Hanley O, Venkatesh B, Duboule D, Dasen JS. Evolving Hox activity profiles govern diversity in locomotor systems. Dev Cell 2014; 29:171-87. [PMID: 24746670 DOI: 10.1016/j.devcel.2014.03.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/07/2014] [Accepted: 03/13/2014] [Indexed: 11/28/2022]
Abstract
The emergence of limb-driven locomotor behaviors was a key event in the evolution of vertebrates and fostered the transition from aquatic to terrestrial life. We show that the generation of limb-projecting lateral motor column (LMC) neurons in mice relies on a transcriptional autoregulatory module initiated via transient activity of multiple genes within the HoxA and HoxC clusters. Repression of this module at thoracic levels restricts expression of LMC determinants, thus dictating LMC position relative to the limbs. This suppression is mediated by a key regulatory domain that is specifically found in the Hoxc9 proteins of appendage-bearing vertebrates. The profile of Hoxc9 expression inversely correlates with LMC position in land vertebrates and likely accounts for the absence of LMC neurons in limbless species such as snakes. Thus, modulation of both Hoxc9 protein function and Hoxc9 gene expression likely contributed to evolutionary transitions between undulatory and ambulatory motor circuit connectivity programs.
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Affiliation(s)
- Heekyung Jung
- Howard Hughes Medical Institute, NYU Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA
| | | | - Natalia Soshnikova
- Department of Genetics and Evolution, University of Geneva, Sciences III, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany
| | - Olivia Hanley
- Howard Hughes Medical Institute, NYU Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA
| | - Byrappa Venkatesh
- Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, A(∗)STAR, Biopolis, Singapore 138673, Singapore; Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Denis Duboule
- Department of Genetics and Evolution, University of Geneva, Sciences III, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; School of Life Sciences, Ecole Polytechnique Fédérale, 1015 Lausanne, Switzerland
| | - Jeremy S Dasen
- Howard Hughes Medical Institute, NYU Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA.
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