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Cucun G, Köhler M, Pfitsch S, Rastegar S. Insights into the mechanisms of neuron generation and specification in the zebrafish ventral spinal cord. FEBS J 2024; 291:646-662. [PMID: 37498183 DOI: 10.1111/febs.16913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/20/2023] [Accepted: 07/25/2023] [Indexed: 07/28/2023]
Abstract
The vertebrate nervous system is composed of a wide range of neurons and complex synaptic connections, raising the intriguing question of how neuronal diversity is generated. The spinal cord provides an excellent model for exploring the mechanisms governing neuronal diversity due to its simple neural network and the conserved molecular processes involved in neuron formation and specification during evolution. This review specifically examines two distinct progenitor domains present in the zebrafish ventral spinal cord: the lateral floor plate (LFP) and the p2 progenitor domain. The LFP is responsible for the production of GABAergic Kolmer-Agduhr neurons (KA″), glutamatergic V3 neurons, and intraspinal serotonergic neurons, while the p2 domain generates V2 precursors that subsequently differentiate into three unique subpopulations of V2 neurons, namely glutamatergic V2a, GABAergic V2b, and glycinergic V2s. Based on recent findings, we will examine the fundamental signaling pathways and transcription factors that play a key role in the specification of these diverse neurons and neuronal subtypes derived from the LFP and p2 progenitor domains.
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Affiliation(s)
- Gokhan Cucun
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Melina Köhler
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Sabrina Pfitsch
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Sepand Rastegar
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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2
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England SJ, Rusnock AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular analyses of zebrafish V0v spinal interneurons and identification of transcriptional regulators downstream of Evx1 and Evx2 in these cells. Neural Dev 2023; 18:8. [PMID: 38017520 PMCID: PMC10683209 DOI: 10.1186/s13064-023-00176-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: 08/23/2023] [Accepted: 10/12/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. METHODS To identify candidate members of V0v gene regulatory networks, we FAC-sorted wild-type and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. RESULTS Our data reveal two molecularly distinct subtypes of zebrafish V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuron expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. CONCLUSIONS This study identifies two molecularly distinct subsets of zebrafish V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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Affiliation(s)
| | | | - Amra Mujcic
- Biology Department, Syracuse University, Syracuse, NY, USA
| | | | - Sarah de Jager
- Physiology, Development and Neuroscience Department, Cambridge University, Cambridge, UK
| | | | - José L Juárez-Morales
- Biology Department, Syracuse University, Syracuse, NY, USA
- Programa de IxM-CONAHCYT, Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), La Paz, Baja California Sur, México
| | | | - Ginny Grieb
- Biology Department, Syracuse University, Syracuse, NY, USA
| | - Santanu Banerjee
- Biological Sciences Department, SUNY-Cortland, Cortland, NY, USA
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3
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England SJ, Woodard AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular Analyses of V0v Spinal Interneurons and Identification of Transcriptional Regulators Downstream of Evx1 and Evx2 in these Cells. RESEARCH SQUARE 2023:rs.3.rs-3290462. [PMID: 37693471 PMCID: PMC10491344 DOI: 10.21203/rs.3.rs-3290462/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Background V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. Methods To identify candidate members of V0v gene regulatory networks, we FAC-sorted WT and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. Results Our data reveal two molecularly distinct subtypes of V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuronal expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. Conclusions This study identifies two molecularly distinct subsets of V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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4
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Abstract
Vitamin A (retinol) is an important nutrient for embryonic development and adult health. Early studies identified retinoic acid (RA) as a metabolite of retinol, however, its importance was not apparent. Later, it was observed that RA treatment of vertebrate embryos had teratogenic effects on limb development. Subsequently, the discovery of nuclear RA receptors (RARs) revealed that RA controls gene expression directly at the transcriptional level through a process referred to as RA signaling. This important discovery led to further studies demonstrating that RA and RARs are required for normal embryonic development. The determination of RA function during normal development has been challenging as RA gain-of-function studies often lead to conclusions about normal development that conflict with RAR or RA loss-of-function studies. However, genetic loss-of-function studies have identified direct target genes of endogenous RA/RAR that are required for normal development of specific tissues. Thus, genetic loss-of-function studies that eliminate RARs or RA-generating enzymes have been instrumental in revealing that RA signaling is required for normal early development of many organs and tissues, including the hindbrain, posterior body axis, somites, spinal cord, forelimbs, heart, and eye.
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Affiliation(s)
- Marie Berenguer
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gregg Duester
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
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5
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Xu Y, Sun H. Involvement of hedgehog signaling in all-trans retinoic acid-mediated suppression of colon cancer. Am J Transl Res 2022; 14:6536-6549. [PMID: 36247302 PMCID: PMC9556466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/17/2022] [Indexed: 06/16/2023]
Abstract
UNLABELLED All-trans retinoic acid (ATRA) exerts tumor-inhibitory effects on acute leukemia and certain types of solid tumors. This study was designed to evaluate the mechanism on ATRA-mediated suppression of colon cancer based on the sonic hedgehog (Shh) signaling pathway. METHODS Normal intestinal epithelial cells and three colon cancer cell lines were studied to evaluate the inhibitory effect of ATRA on tumor cell activity. The inhibitory effect of ATRA on colon cancer was evaluated by cell invasion, migration, and apoptosis of HCT116 cells. Retinoic acid receptor (RAR)- and Shh-related protein expression was assessed. RESULTS ATRA administration inhibited the activity of three different colon cancer lines, but did not inhibit the activity of normal intestinal epithelial cells. Administration of ATRA induced apoptosis and restricted invasion and migration of HCT116 colon cancer cells. Administration of ATRA also increased expression of RAR and transmembrane receptor patched 1 (Ptch1), and decreased expression of the smoothened (Smo) and glioma-associated oncogene homolog1 (Gli-1). RARα and RARβ agonists inhibited Shh signaling, and the mediating effect of ATRA on Shh signaling was abolished by RARα or RARβ antagonists. The combination of purmorphamine (Smo agonist) and ATRA partially abolished the inhibitory effect of ATRA on the proliferation of colon cancer cells. In vivo studies showed that ATRA inhibited tumor growth, which was accompanied by down-regulation of the Shh signaling pathway. CONCLUSIONS ATRA inhibits the growth of colon cancer by downregulating the Shh pathway, which further verifies the anticancer activity of ATRA.
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Affiliation(s)
- Yu Xu
- Suzhou Medical College of Soochow UniversitySuzhou 215000, Jiangsu, China
- Department of General Surgery, The First Affiliated Hospital of Jinzhou Medical UniversityJinzhou 121000, Liaoning, China
| | - Hongzhi Sun
- Suzhou Medical College of Soochow UniversitySuzhou 215000, Jiangsu, China
- Department of General Surgery, The First Affiliated Hospital of Jinzhou Medical UniversityJinzhou 121000, Liaoning, China
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6
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Hadjivasiliou Z, Hunter G. Talking to your neighbors across scales: Long-distance Notch signaling during patterning. Curr Top Dev Biol 2022; 150:299-334. [DOI: 10.1016/bs.ctdb.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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The presynaptic glycine transporter GlyT2 is regulated by the Hedgehog pathway in vitro and in vivo. Commun Biol 2021; 4:1197. [PMID: 34663888 PMCID: PMC8523746 DOI: 10.1038/s42003-021-02718-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/22/2021] [Indexed: 01/20/2023] Open
Abstract
The identity of a glycinergic synapse is maintained presynaptically by the activity of a surface glycine transporter, GlyT2, which recaptures glycine back to presynaptic terminals to preserve vesicular glycine content. GlyT2 loss-of-function mutations cause Hyperekplexia, a rare neurological disease in which loss of glycinergic neurotransmission causes generalized stiffness and strong motor alterations. However, the molecular underpinnings controlling GlyT2 activity remain poorly understood. In this work, we identify the Hedgehog pathway as a robust controller of GlyT2 expression and transport activity. Modulating the activation state of the Hedgehog pathway in vitro in rodent primary spinal cord neurons or in vivo in zebrafish embryos induced a selective control in GlyT2 expression, regulating GlyT2 transport activity. Our results indicate that activation of Hedgehog reduces GlyT2 expression by increasing its ubiquitination and degradation. This work describes a new molecular link between the Hedgehog signaling pathway and presynaptic glycine availability. By modulating the activation state of the Hedgehog pathway, de la Rocha-Muñoz et al demonstrate that Hedgehog signaling controls the expression and transport activity of the neuronal glycine transporter GlyT2. This work begins to reveal a potential link between the Hedgehog signaling pathway and presynaptic glycine availability.
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Roussel Y, Gaudreau SF, Kacer ER, Sengupta M, Bui TV. Modeling spinal locomotor circuits for movements in developing zebrafish. eLife 2021; 10:e67453. [PMID: 34473059 PMCID: PMC8492062 DOI: 10.7554/elife.67453] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 09/01/2021] [Indexed: 01/16/2023] Open
Abstract
Many spinal circuits dedicated to locomotor control have been identified in the developing zebrafish. How these circuits operate together to generate the various swimming movements during development remains to be clarified. In this study, we iteratively built models of developing zebrafish spinal circuits coupled to simplified musculoskeletal models that reproduce coiling and swimming movements. The neurons of the models were based upon morphologically or genetically identified populations in the developing zebrafish spinal cord. We simulated intact spinal circuits as well as circuits with silenced neurons or altered synaptic transmission to better understand the role of specific spinal neurons. Analysis of firing patterns and phase relationships helped to identify possible mechanisms underlying the locomotor movements of developing zebrafish. Notably, our simulations demonstrated how the site and the operation of rhythm generation could transition between coiling and swimming. The simulations also underlined the importance of contralateral excitation to multiple tail beats. They allowed us to estimate the sensitivity of spinal locomotor networks to motor command amplitude, synaptic weights, length of ascending and descending axons, and firing behavior. These models will serve as valuable tools to test and further understand the operation of spinal circuits for locomotion.
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Affiliation(s)
- Yann Roussel
- Brain and Mind Research Institute, Centre for Neural Dynamics, Department of Biology, University of OttawaOttawaCanada
- Blue Brain Project, École Polytechnique Fédérale de LausanneGenèveSwitzerland
| | - Stephanie F Gaudreau
- Brain and Mind Research Institute, Centre for Neural Dynamics, Department of Biology, University of OttawaOttawaCanada
| | - Emily R Kacer
- Brain and Mind Research Institute, Centre for Neural Dynamics, Department of Biology, University of OttawaOttawaCanada
| | - Mohini Sengupta
- Washington University School of Medicine, Department of NeuroscienceSt LouisUnited States
| | - Tuan V Bui
- Brain and Mind Research Institute, Centre for Neural Dynamics, Department of Biology, University of OttawaOttawaCanada
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9
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England SJ, Cerda GA, Kowalchuk A, Sorice T, Grieb G, Lewis KE. Hmx3a Has Essential Functions in Zebrafish Spinal Cord, Ear and Lateral Line Development. Genetics 2020; 216:1153-1185. [PMID: 33077489 PMCID: PMC7768253 DOI: 10.1534/genetics.120.303748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/14/2020] [Indexed: 11/30/2022] Open
Abstract
Transcription factors that contain a homeodomain DNA-binding domain have crucial functions in most aspects of cellular function and embryonic development in both animals and plants. Hmx proteins are a subfamily of NK homeodomain-containing proteins that have fundamental roles in development of sensory structures such as the eye and the ear. However, Hmx functions in spinal cord development have not been analyzed. Here, we show that zebrafish (Danio rerio) hmx2 and hmx3a are coexpressed in spinal dI2 and V1 interneurons, whereas hmx3b, hmx1, and hmx4 are not expressed in spinal cord. Using mutational analyses, we demonstrate that, in addition to its previously reported role in ear development, hmx3a is required for correct specification of a subset of spinal interneuron neurotransmitter phenotypes, as well as correct lateral line progression and survival to adulthood. Surprisingly, despite similar expression patterns of hmx2 and hmx3a during embryonic development, zebrafish hmx2 mutants are viable and have no obviously abnormal phenotypes in sensory structures or neurons that require hmx3a In addition, embryos homozygous for deletions of both hmx2 and hmx3a have identical phenotypes to severe hmx3a single mutants. However, mutating hmx2 in hypomorphic hmx3a mutants that usually develop normally, results in abnormal ear and lateral line phenotypes. This suggests that while hmx2 cannot compensate for loss of hmx3a, it does function in these developmental processes, although to a much lesser extent than hmx3a More surprisingly, our mutational analyses suggest that Hmx3a may not require its homeodomain DNA-binding domain for its roles in viability or embryonic development.
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Affiliation(s)
| | - Gustavo A Cerda
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB2 3DY, UK
| | | | - Taylor Sorice
- Department of Biology, Syracuse University, New York 13244
| | - Ginny Grieb
- Department of Biology, Syracuse University, New York 13244
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10
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Yang L, Wang F, Strähle U. The Genetic Programs Specifying Kolmer-Agduhr Interneurons. Front Neurosci 2020; 14:577879. [PMID: 33162880 PMCID: PMC7581942 DOI: 10.3389/fnins.2020.577879] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/15/2020] [Indexed: 01/21/2023] Open
Abstract
Kolmer-Agduhr (KA) cells are a subgroup of interneurons positioned adjacent to the neurocoele with cilia on the apical surface protruding into the central canal of the spinal cord. Although KA cells were identified almost a century ago, their development and functions are only beginning to be unfolded. Recent studies have revealed the characteristics of KA cells in greater detail, including their spatial distribution, the timing of their differentiation, and their specification via extrinsic signaling and a unique combination of transcription factors in zebrafish and mouse. Cell lineage-tracing experiments have demonstrated that two subsets of KA cells, named KA' and KA" cells, differentiate from motoneuronal progenitors and floor-plate precursors, respectively, in both zebrafish and mouse. Although KA' and KA" cells originate from different progenitors/precursors, they each share a common set of transcription factors. Intriguingly, the combination of transcription factors that promote the acquisition of KA' cell characteristics differs from those that promote a KA" cell identity. In addition, KA' and KA" cells exhibit separable neuronal targets and differential responses to bending of the spinal cord. In this review, we summarize what is currently known about the genetic programs defining the identities of KA' and KA" cell identities. We then discuss how these two subgroups of KA cells are genetically specified.
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Affiliation(s)
- Lixin Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China.,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Feifei Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Uwe Strähle
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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11
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Hadjivasiliou Z, Moore RE, McIntosh R, Galea GL, Clarke JDW, Alexandre P. Basal Protrusions Mediate Spatiotemporal Patterns of Spinal Neuron Differentiation. Dev Cell 2020; 49:907-919.e10. [PMID: 31211994 PMCID: PMC6584357 DOI: 10.1016/j.devcel.2019.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/26/2019] [Accepted: 05/20/2019] [Indexed: 12/22/2022]
Abstract
During early spinal cord development, neurons of particular subtypes differentiate with a sparse periodic pattern while later neurons differentiate in the intervening space to eventually produce continuous columns of similar neurons. The mechanisms that regulate this spatiotemporal pattern are unknown. In vivo imaging in zebrafish reveals that differentiating spinal neurons transiently extend two long protrusions along the basal surface of the spinal cord before axon initiation. These protrusions express Delta protein, consistent with the hypothesis they influence Notch signaling at a distance of several cell diameters. Experimental reduction of Laminin expression leads to smaller protrusions and shorter distances between differentiating neurons. The experimental data and a theoretical model support the proposal that neuronal differentiation pattern is regulated by transient basal protrusions that deliver temporally controlled lateral inhibition mediated at a distance. This work uncovers a stereotyped protrusive activity of newborn neurons that organize long-distance spatiotemporal patterning of differentiation.
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Affiliation(s)
- Zena Hadjivasiliou
- Department of Biochemistry, Science II, University of Geneva, Geneva, Switzerland; Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1N 1EH, UK
| | - Rachel E Moore
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE1 1UL, UK
| | - Rebecca McIntosh
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE1 1UL, UK; Developmental Biology and Cancer, UCL GOS Institute of Child Health, London WC1N 1EH, UK
| | - Gabriel L Galea
- Developmental Biology and Cancer, UCL GOS Institute of Child Health, London WC1N 1EH, UK
| | - Jonathan D W Clarke
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE1 1UL, UK.
| | - Paula Alexandre
- Developmental Biology and Cancer, UCL GOS Institute of Child Health, London WC1N 1EH, UK.
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12
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Abstract
Retinoic acid (RA), a metabolite of retinol (vitamin A), functions as a ligand for nuclear RA receptors (RARs) that regulate development of chordate animals. RA-RARs can activate or repress transcription of key developmental genes. Genetic studies in mouse and zebrafish embryos that are deficient in RA-generating enzymes or RARs have been instrumental in identifying RA functions, revealing that RA signaling regulates development of many organs and tissues, including the body axis, spinal cord, forelimbs, heart, eye and reproductive tract. An understanding of the normal functions of RA signaling during development will guide efforts for use of RA as a therapeutic agent to improve human health. Here, we provide an overview of RA signaling and highlight its key functions during development.
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Affiliation(s)
- Norbert B Ghyselinck
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Génétique Fonctionnelle et Cancer, Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Santé et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 rue Laurent Fries, F-67404 Illkirch Cedex, France
| | - Gregg Duester
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
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Zieger E, Garbarino G, Robert NSM, Yu JK, Croce JC, Candiani S, Schubert M. Retinoic acid signaling and neurogenic niche regulation in the developing peripheral nervous system of the cephalochordate amphioxus. Cell Mol Life Sci 2018; 75:2407-2429. [PMID: 29387904 PMCID: PMC11105557 DOI: 10.1007/s00018-017-2734-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/19/2017] [Indexed: 10/18/2022]
Abstract
The retinoic acid (RA) signaling pathway regulates axial patterning and neurogenesis in the developing central nervous system (CNS) of chordates, but little is known about its roles during peripheral nervous system (PNS) formation and about how these roles might have evolved. This study assesses the requirement of RA signaling for establishing a functional PNS in the cephalochordate amphioxus, the best available stand-in for the ancestral chordate condition. Pharmacological manipulation of RA signaling levels during embryogenesis reduces the ability of amphioxus larvae to respond to sensory stimulation and alters the number and distribution of ectodermal sensory neurons (ESNs) in a stage- and context-dependent manner. Using gene expression assays combined with immunohistochemistry, we show that this is because RA signaling specifically acts on a small population of soxb1c-expressing ESN progenitors, which form a neurogenic niche in the trunk ectoderm, to modulate ESN production during elongation of the larval body. Our findings reveal an important role for RA signaling in regulating neurogenic niche activity in the larval amphioxus PNS. Although only few studies have addressed this issue so far, comparable RA signaling functions have been reported for neurogenic niches in the CNS and in certain neurogenic placode derivatives of vertebrates. Accordingly, the here-described mechanism is likely a conserved feature of chordate embryonic and adult neural development.
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Affiliation(s)
- Elisabeth Zieger
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Observatoire Océanologique de Villefranche-sur-Mer, Sorbonne Universités, UPMC Université Paris 06, CNRS, 181 Chemin du Lazaret, 06230, Villefranche-sur-Mer, France
| | - Greta Garbarino
- Department of Earth, Environment and Life Sciences (Dipartimento di Scienze della Terra dell'Ambiente e della Vita, DISTAV), University of Genoa, Viale Benedetto XV 5, 16132, Genoa, Italy
| | - Nicolas S M Robert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Observatoire Océanologique de Villefranche-sur-Mer, Sorbonne Universités, UPMC Université Paris 06, CNRS, 181 Chemin du Lazaret, 06230, Villefranche-sur-Mer, France
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jenifer C Croce
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Observatoire Océanologique de Villefranche-sur-Mer, Sorbonne Universités, UPMC Université Paris 06, CNRS, 181 Chemin du Lazaret, 06230, Villefranche-sur-Mer, France
| | - Simona Candiani
- Department of Earth, Environment and Life Sciences (Dipartimento di Scienze della Terra dell'Ambiente e della Vita, DISTAV), University of Genoa, Viale Benedetto XV 5, 16132, Genoa, Italy
| | - Michael Schubert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Observatoire Océanologique de Villefranche-sur-Mer, Sorbonne Universités, UPMC Université Paris 06, CNRS, 181 Chemin du Lazaret, 06230, Villefranche-sur-Mer, France.
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Andrzejczuk LA, Banerjee S, England SJ, Voufo C, Kamara K, Lewis KE. Tal1, Gata2a, and Gata3 Have Distinct Functions in the Development of V2b and Cerebrospinal Fluid-Contacting KA Spinal Neurons. Front Neurosci 2018; 12:170. [PMID: 29651232 PMCID: PMC5884927 DOI: 10.3389/fnins.2018.00170] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 03/02/2018] [Indexed: 12/17/2022] Open
Abstract
Vertebrate locomotor circuitry contains distinct classes of ventral spinal cord neurons which each have particular functional properties. While we know some of the genes expressed by each of these cell types, we do not yet know how several of these neurons are specified. Here, we investigate the functions of Tal1, Gata2a, and Gata3 transcription factors in the development of two of these populations of neurons with important roles in locomotor circuitry: V2b neurons and cerebrospinal fluid-contacting Kolmer-Agduhr (KA) neurons (also called CSF-cNs). Our data provide the first demonstration, in any vertebrate, that Tal1 and Gata3 are required for correct development of KA and V2b neurons, respectively. We also uncover differences in the genetic regulation of V2b cell development in zebrafish compared to mouse. In addition, we demonstrate that Sox1a and Sox1b are expressed by KA and V2b neurons in zebrafish, which differs from mouse, where Sox1 is expressed by V2c neurons. KA neurons can be divided into ventral KA″ neurons and more dorsal KA′ neurons. Consistent with previous morpholino experiments, our mutant data suggest that Tal1 and Gata3 are required in KA′ but not KA″ cells, whereas Gata2a is required in KA″ but not KA′ cells, even though both of these cell types co-express all three of these transcription factors. In gata2a mutants, cells in the KA″ region of the spinal cord lose expression of most KA″ genes and there is an increase in the number of cells expressing V3 genes, suggesting that Gata2a is required to specify KA″ and repress V3 fates in cells that normally develop into KA″ neurons. On the other hand, our data suggest that Gata3 and Tal1 are both required for KA′ neurons to differentiate from progenitor cells. In the KA′ region of these mutants, cells no longer express KA′ markers and there is an increase in the number of mitotically-active cells. Finally, our data demonstrate that all three of these transcription factors are required for later stages of V2b neuron differentiation and that Gata2a and Tal1 have different functions in V2b development in zebrafish than in mouse.
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Affiliation(s)
| | - Santanu Banerjee
- Department of Biology, Syracuse University, Syracuse, NY, United States
| | | | - Christiane Voufo
- Department of Biology, Syracuse University, Syracuse, NY, United States
| | - Kadiah Kamara
- Department of Biology, Syracuse University, Syracuse, NY, United States
| | - Katharine E Lewis
- Department of Biology, Syracuse University, Syracuse, NY, United States
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15
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Cardozo MJ, Mysiak KS, Becker T, Becker CG. Reduce, reuse, recycle – Developmental signals in spinal cord regeneration. Dev Biol 2017; 432:53-62. [DOI: 10.1016/j.ydbio.2017.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 02/03/2017] [Accepted: 05/11/2017] [Indexed: 02/06/2023]
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Danesin C, Soula C. Moving the Shh Source over Time: What Impact on Neural Cell Diversification in the Developing Spinal Cord? J Dev Biol 2017; 5:jdb5020004. [PMID: 29615562 PMCID: PMC5831764 DOI: 10.3390/jdb5020004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/29/2017] [Accepted: 04/06/2017] [Indexed: 12/18/2022] Open
Abstract
A substantial amount of data has highlighted the crucial influence of Shh signalling on the generation of diverse classes of neurons and glial cells throughout the developing central nervous system. A critical step leading to this diversity is the establishment of distinct neural progenitor cell domains during the process of pattern formation. The forming spinal cord, in particular, has served as an excellent model to unravel how progenitor cells respond to Shh to produce the appropriate pattern. In recent years, considerable advances have been made in our understanding of important parameters that control the temporal and spatial interpretation of the morphogen signal at the level of Shh-receiving progenitor cells. Although less studied, the identity and position of Shh source cells also undergo significant changes over time, raising the question of how moving the Shh source contributes to cell diversification in response to the morphogen. Here, we focus on the dynamics of Shh-producing cells and discuss specific roles for these time-variant Shh sources with regard to the temporal events occurring in the receiving field.
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Affiliation(s)
- Cathy Danesin
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, 31520 Toulouse, France.
| | - Cathy Soula
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, 31520 Toulouse, France.
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17
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The dual developmental origin of spinal cerebrospinal fluid-contacting neurons gives rise to distinct functional subtypes. Sci Rep 2017; 7:719. [PMID: 28389647 PMCID: PMC5428266 DOI: 10.1038/s41598-017-00350-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/30/2017] [Indexed: 11/30/2022] Open
Abstract
Chemical and mechanical cues from the cerebrospinal fluid (CSF) can affect the development and function of the central nervous system (CNS). How such cues are detected and relayed to the CNS remains elusive. Cerebrospinal fluid-contacting neurons (CSF-cNs) situated at the interface between the CSF and the CNS are ideally located to convey such information to local networks. In the spinal cord, these GABAergic neurons expressing the PKD2L1 channel extend an apical extension into the CSF and an ascending axon in the spinal cord. In zebrafish and mouse spinal CSF-cNs originate from two distinct progenitor domains characterized by distinct cascades of transcription factors. Here we ask whether these neurons with different developmental origins differentiate into cells types with different functional properties. We show in zebrafish larva that the expression of specific markers, the morphology of the apical extension and axonal projections, as well as the neuronal targets contacted by CSF-cN axons, distinguish the two CSF-cN subtypes. Altogether our study demonstrates that the developmental origins of spinal CSF-cNs give rise to two distinct functional populations of sensory neurons. This work opens novel avenues to understand how these subtypes may carry distinct functions related to development of the spinal cord, locomotion and posture.
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Juárez-Morales JL, Martinez-De Luna RI, Zuber ME, Roberts A, Lewis KE. Zebrafish transgenic constructs label specific neurons in Xenopus laevis spinal cord and identify frog V0v spinal neurons. Dev Neurobiol 2017; 77:1007-1020. [PMID: 28188691 DOI: 10.1002/dneu.22490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/26/2017] [Accepted: 02/08/2017] [Indexed: 12/19/2022]
Abstract
A correctly functioning spinal cord is crucial for locomotion and communication between body and brain but there are fundamental gaps in our knowledge of how spinal neuronal circuitry is established and functions. To understand the genetic program that regulates specification and functions of this circuitry, we need to connect neuronal molecular phenotypes with physiological analyses. Studies using Xenopus laevis tadpoles have increased our understanding of spinal cord neuronal physiology and function, particularly in locomotor circuitry. However, the X. laevis tetraploid genome and long generation time make it difficult to investigate how neurons are specified. The opacity of X. laevis embryos also makes it hard to connect functional classes of neurons and the genes that they express. We demonstrate here that Tol2 transgenic constructs using zebrafish enhancers that drive expression in specific zebrafish spinal neurons label equivalent neurons in X. laevis and that the incorporation of a Gal4:UAS amplification cassette enables cells to be observed in live X. laevis tadpoles. This technique should enable the molecular phenotypes, morphologies and physiologies of distinct X. laevis spinal neurons to be examined together in vivo. We have used an islet1 enhancer to label Rohon-Beard sensory neurons and evx enhancers to identify V0v neurons, for the first time, in X. laevis spinal cord. Our work demonstrates the homology of spinal cord circuitry in zebrafish and X. laevis, suggesting that future work could combine their relative strengths to elucidate a more complete picture of how vertebrate spinal cord neurons are specified, and function to generate behavior. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1007-1020, 2017.
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Affiliation(s)
- José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244.,Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - Reyna I Martinez-De Luna
- The Center for Vision Research, Department of Ophthalmology, SUNY Upstate Medical University, Institute for Human Performance, 505 Irving Ave. Syracuse, New York, 13210
| | - Michael E Zuber
- The Center for Vision Research, Department of Ophthalmology, SUNY Upstate Medical University, Institute for Human Performance, 505 Irving Ave. Syracuse, New York, 13210
| | - Alan Roberts
- School of Biological Sciences, Bristol University, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244
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New Insights Into the Roles of Retinoic Acid Signaling in Nervous System Development and the Establishment of Neurotransmitter Systems. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 330:1-84. [PMID: 28215529 DOI: 10.1016/bs.ircmb.2016.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Secreted chiefly from the underlying mesoderm, the morphogen retinoic acid (RA) is well known to contribute to the specification, patterning, and differentiation of neural progenitors in the developing vertebrate nervous system. Furthermore, RA influences the subtype identity and neurotransmitter phenotype of subsets of maturing neurons, although relatively little is known about how these functions are mediated. This review provides a comprehensive overview of the roles played by RA signaling during the formation of the central and peripheral nervous systems of vertebrates and highlights its effects on the differentiation of several neurotransmitter systems. In addition, the evolutionary history of the RA signaling system is discussed, revealing both conserved properties and alternate modes of RA action. It is proposed that comparative approaches should be employed systematically to expand our knowledge of the context-dependent cellular mechanisms controlled by the multifunctional signaling molecule RA.
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Hilinski WC, Bostrom JR, England SJ, Juárez-Morales JL, de Jager S, Armant O, Legradi J, Strähle U, Link BA, Lewis KE. Lmx1b is required for the glutamatergic fates of a subset of spinal cord neurons. Neural Dev 2016; 11:16. [PMID: 27553035 PMCID: PMC4995821 DOI: 10.1186/s13064-016-0070-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/08/2016] [Indexed: 01/27/2023] Open
Abstract
Background Alterations in neurotransmitter phenotypes of specific neurons can cause imbalances in excitation and inhibition in the central nervous system (CNS), leading to diseases. Therefore, the correct specification and maintenance of neurotransmitter phenotypes is vital. As with other neuronal properties, neurotransmitter phenotypes are often specified and maintained by particular transcription factors. However, the specific molecular mechanisms and transcription factors that regulate neurotransmitter phenotypes remain largely unknown. Methods In this paper we use single mutant, double mutant and transgenic zebrafish embryos to elucidate the functions of Lmx1ba and Lmx1bb in the regulation of spinal cord interneuron neurotransmitter phenotypes. Results We demonstrate that lmx1ba and lmx1bb are both expressed in zebrafish spinal cord and that lmx1bb is expressed by both V0v cells and dI5 cells. Our functional analyses demonstrate that these transcription factors are not required for neurotransmitter fate specification at early stages of development, but that in embryos with at least two lmx1ba and/or lmx1bb mutant alleles there is a reduced number of excitatory (glutamatergic) spinal interneurons at later stages of development. In contrast, there is no change in the numbers of V0v or dI5 cells. These data suggest that lmx1b-expressing spinal neurons still form normally, but at least a subset of them lose, or do not form, their normal excitatory fates. As the reduction in glutamatergic cells is only seen at later stages of development, Lmx1b is probably required either for the maintenance of glutamatergic fates or to specify glutamatergic phenotypes of a subset of later forming neurons. Using double labeling experiments, we also show that at least some of the cells that lose their normal glutamatergic phenotype are V0v cells. Finally, we also establish that Evx1 and Evx2, two transcription factors that are required for V0v cells to acquire their excitatory neurotransmitter phenotype, are also required for lmx1ba and lmx1bb expression in these cells, suggesting that Lmx1ba and Lmx1bb act downstream of Evx1 and Evx2 in V0v cells. Conclusions Lmx1ba and Lmx1bb function at least partially redundantly in the spinal cord and three functional lmx1b alleles are required in zebrafish for correct numbers of excitatory spinal interneurons at later developmental stages. Taken together, our data significantly enhance our understanding of how spinal cord neurotransmitter fates are regulated.
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Affiliation(s)
- William C Hilinski
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.,Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Avenue, Syracuse, NY, 13210, USA
| | - Jonathan R Bostrom
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Samantha J England
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Sarah de Jager
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Olivier Armant
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Jessica Legradi
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Uwe Strähle
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Brian A Link
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
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21
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Ghosh S, Hui SP. Regeneration of Zebrafish CNS: Adult Neurogenesis. Neural Plast 2016; 2016:5815439. [PMID: 27382491 PMCID: PMC4921647 DOI: 10.1155/2016/5815439] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022] Open
Abstract
Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibians are capable of regenerating a variety of complex organs through epimorphosis. Zebrafish is an excellent animal model, which can repair several organs like damaged retina, severed spinal cord, injured brain and heart, and amputated fins. The focus of the present paper is on spinal cord regeneration in adult zebrafish. We intend to discuss our current understanding of the cellular and molecular mechanism(s) that allows formation of proliferating progenitors and controls neurogenesis, which involve changes in epigenetic and transcription programs. Unlike mammals, zebrafish retains radial glia, a nonneuronal cell type in their adult central nervous system. Injury induced proliferation involves radial glia which proliferate, transcribe embryonic genes, and can give rise to new neurons. Recent technological development of exquisite molecular tools in zebrafish, such as cell ablation, lineage analysis, and novel and substantial microarray, together with advancement in stem cell biology, allowed us to investigate how progenitor cells contribute to the generation of appropriate structures and various underlying mechanisms like reprogramming.
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Affiliation(s)
- Sukla Ghosh
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Subhra Prakash Hui
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
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22
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Ohnmacht J, Yang Y, Maurer GW, Barreiro-Iglesias A, Tsarouchas TM, Wehner D, Sieger D, Becker CG, Becker T. Spinal motor neurons are regenerated after mechanical lesion and genetic ablation in larval zebrafish. Development 2016; 143:1464-74. [PMID: 26965370 PMCID: PMC4986163 DOI: 10.1242/dev.129155] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 02/25/2016] [Indexed: 01/14/2023]
Abstract
In adult zebrafish, relatively quiescent progenitor cells show lesion-induced generation of motor neurons. Developmental motor neuron generation from the spinal motor neuron progenitor domain (pMN) sharply declines at 48 hours post-fertilisation (hpf). After that, mostly oligodendrocytes are generated from the same domain. We demonstrate here that within 48 h of a spinal lesion or specific genetic ablation of motor neurons at 72 hpf, the pMN domain reverts to motor neuron generation at the expense of oligodendrogenesis. By contrast, generation of dorsal Pax2-positive interneurons was not altered. Larval motor neuron regeneration can be boosted by dopaminergic drugs, similar to adult regeneration. We use larval lesions to show that pharmacological suppression of the cellular response of the innate immune system inhibits motor neuron regeneration. Hence, we have established a rapid larval regeneration paradigm. Either mechanical lesions or motor neuron ablation is sufficient to reveal a high degree of developmental flexibility of pMN progenitor cells. In addition, we show an important influence of the immune system on motor neuron regeneration from these progenitor cells.
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Affiliation(s)
- Jochen Ohnmacht
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Yujie Yang
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Gianna W Maurer
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Antón Barreiro-Iglesias
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Themistoklis M Tsarouchas
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Daniel Wehner
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Dirk Sieger
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Catherina G Becker
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Thomas Becker
- Centre for Neuroregeneration, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
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Juárez-Morales JL, Schulte CJ, Pezoa SA, Vallejo GK, Hilinski WC, England SJ, de Jager S, Lewis KE. Evx1 and Evx2 specify excitatory neurotransmitter fates and suppress inhibitory fates through a Pax2-independent mechanism. Neural Dev 2016; 11:5. [PMID: 26896392 PMCID: PMC4759709 DOI: 10.1186/s13064-016-0059-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/04/2016] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND For neurons to function correctly in neuronal circuitry they must utilize appropriate neurotransmitters. However, even though neurotransmitter specificity is one of the most important and defining properties of a neuron we still do not fully understand how neurotransmitter fates are specified during development. Most neuronal properties are determined by the transcription factors that neurons express as they start to differentiate. While we know a few transcription factors that specify the neurotransmitter fates of particular neurons, there are still many spinal neurons for which the transcription factors specifying this critical phenotype are unknown. Strikingly, all of the transcription factors that have been identified so far as specifying inhibitory fates in the spinal cord act through Pax2. Even Tlx1 and Tlx3, which specify the excitatory fates of dI3 and dI5 spinal neurons work at least in part by down-regulating Pax2. METHODS In this paper we use single and double mutant zebrafish embryos to identify the spinal cord functions of Evx1 and Evx2. RESULTS We demonstrate that Evx1 and Evx2 are expressed by spinal cord V0v cells and we show that these cells develop into excitatory (glutamatergic) Commissural Ascending (CoSA) interneurons. In the absence of both Evx1 and Evx2, V0v cells still form and develop a CoSA morphology. However, they lose their excitatory fate and instead express markers of a glycinergic fate. Interestingly, they do not express Pax2, suggesting that they are acquiring their inhibitory fate through a novel Pax2-independent mechanism. CONCLUSIONS Evx1 and Evx2 are required, partially redundantly, for spinal cord V0v cells to become excitatory (glutamatergic) interneurons. These results significantly increase our understanding of the mechanisms of neuronal specification and the genetic networks involved in these processes.
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Affiliation(s)
- José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Claus J Schulte
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Sofia A Pezoa
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Grace K Vallejo
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - William C Hilinski
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Avenue, Syracuse, NY, 13210, USA
| | - Samantha J England
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Sarah de Jager
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
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Djenoune L, Khabou H, Joubert F, Quan FB, Nunes Figueiredo S, Bodineau L, Del Bene F, Burcklé C, Tostivint H, Wyart C. Investigation of spinal cerebrospinal fluid-contacting neurons expressing PKD2L1: evidence for a conserved system from fish to primates. Front Neuroanat 2014; 8:26. [PMID: 24834029 PMCID: PMC4018565 DOI: 10.3389/fnana.2014.00026] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 04/10/2014] [Indexed: 12/11/2022] Open
Abstract
Over 90 years ago, Kolmer and Agduhr identified spinal cerebrospinal fluid-contacting neurons (CSF-cNs) based on their morphology and location within the spinal cord. In more than 200 vertebrate species, they observed ciliated neurons around the central canal that extended a brush of microvilli into the cerebrospinal fluid (CSF). Although their morphology is suggestive of a primitive sensory cell, their function within the vertebrate spinal cord remains unknown. The identification of specific molecular markers for these neurons in vertebrates would benefit the investigation of their physiological roles. PKD2L1, a transient receptor potential channel that could play a role as a sensory receptor, has been found in cells contacting the central canal in mouse. In this study, we demonstrate that PKD2L1 is a specific marker for CSF-cNs in the spinal cord of mouse (Mus musculus), macaque (Macaca fascicularis) and zebrafish (Danio rerio). In these species, the somata of spinal PKD2L1+ CSF-cNs were located below or within the ependymal layer and extended an apical bulbous extension into the central canal. We found GABAergic PKD2L1-expressing CSF-cNs in all three species. We took advantage of the zebrafish embryo for its transparency and rapid development to identify the progenitor domains from which pkd2l1+ CSF-cNs originate. pkd2l1+ CSF-cNs were all GABAergic and organized in two rows—one ventral and one dorsal to the central canal. Their location and marker expression is consistent with previously described Kolmer–Agduhr cells. Accordingly, pkd2l1+ CSF-cNs were derived from the progenitor domains p3 and pMN defined by the expression of nkx2.2a and olig2 transcription factors, respectively. Altogether our results suggest that a system of CSF-cNs expressing the PKD2L1 channel is conserved in the spinal cord across bony vertebrate species.
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Affiliation(s)
- Lydia Djenoune
- Institut du Cerveau et de la Moelle Épinière, Hôpital de la Pitié-Salpêtrière Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR 1127 Paris, France ; Centre National de la Recherche Scientifique UMR 7225 Paris, France ; UPMC Univ. Paris 06 Paris, France ; Muséum National d'Histoire Naturelle Paris, France ; Centre National de la Recherche Scientifique UMR 7221 Paris, France
| | - Hanen Khabou
- Institut du Cerveau et de la Moelle Épinière, Hôpital de la Pitié-Salpêtrière Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR 1127 Paris, France ; Centre National de la Recherche Scientifique UMR 7225 Paris, France ; UPMC Univ. Paris 06 Paris, France
| | - Fanny Joubert
- UPMC Univ. Paris 06 Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR S 1158 Paris, France
| | - Feng B Quan
- Muséum National d'Histoire Naturelle Paris, France ; Centre National de la Recherche Scientifique UMR 7221 Paris, France
| | - Sophie Nunes Figueiredo
- Institut du Cerveau et de la Moelle Épinière, Hôpital de la Pitié-Salpêtrière Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR 1127 Paris, France ; Centre National de la Recherche Scientifique UMR 7225 Paris, France ; UPMC Univ. Paris 06 Paris, France
| | - Laurence Bodineau
- UPMC Univ. Paris 06 Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR S 1158 Paris, France
| | - Filippo Del Bene
- Institut Curie Paris, France ; Centre National de la Recherche Scientifique UMR 3215 Paris, France ; Institut National de la Santé et de la Recherche Médicale U 934 Paris, France
| | - Céline Burcklé
- Institut du Cerveau et de la Moelle Épinière, Hôpital de la Pitié-Salpêtrière Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR 1127 Paris, France ; Centre National de la Recherche Scientifique UMR 7225 Paris, France ; UPMC Univ. Paris 06 Paris, France
| | - Hervé Tostivint
- Muséum National d'Histoire Naturelle Paris, France ; Centre National de la Recherche Scientifique UMR 7221 Paris, France
| | - Claire Wyart
- Institut du Cerveau et de la Moelle Épinière, Hôpital de la Pitié-Salpêtrière Paris, France ; Institut National de la Santé et de la Recherche Médicale UMR 1127 Paris, France ; Centre National de la Recherche Scientifique UMR 7225 Paris, France ; UPMC Univ. Paris 06 Paris, France
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Al Oustah A, Danesin C, Khouri-Farah N, Farreny MA, Escalas N, Cochard P, Glise B, Soula C. Dynamics of sonic hedgehog signaling in the ventral spinal cord are controlled by intrinsic changes in source cells requiring sulfatase 1. Development 2014; 141:1392-403. [PMID: 24595292 DOI: 10.1242/dev.101717] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In the ventral spinal cord, generation of neuronal and glial cell subtypes is controlled by Sonic hedgehog (Shh). This morphogen contributes to cell diversity by regulating spatial and temporal sequences of gene expression during development. Here, we report that establishing Shh source cells is not sufficient to induce the high-threshold response required to specify sequential generation of ventral interneurons and oligodendroglial cells at the right time and place in zebrafish. Instead, we show that Shh-producing cells must repeatedly upregulate the secreted enzyme Sulfatase1 (Sulf1) at two critical time points of development to reach their full inductive capacity. We provide evidence that Sulf1 triggers Shh signaling activity to establish and, later on, modify the spatial arrangement of gene expression in ventral neural progenitors. We further present arguments in favor of Sulf1 controlling Shh temporal activity by stimulating production of active forms of Shh from its source. Our work, by pointing out the key role of Sulf1 in regulating Shh-dependent neural cell diversity, highlights a novel level of regulation, which involves temporal evolution of Shh source properties.
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Affiliation(s)
- Amir Al Oustah
- University of Toulouse, Center for Developmental Biology, UMR 5547 CNRS, 118 Route de Narbonne, 31062 Toulouse, France
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Beck AP, Watt RM, Bonner J. Dissection and lateral mounting of zebrafish embryos: analysis of spinal cord development. J Vis Exp 2014:e50703. [PMID: 24637734 PMCID: PMC4140612 DOI: 10.3791/50703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The zebrafish spinal cord is an effective investigative model for nervous system research for several reasons. First, genetic, transgenic and gene knockdown approaches can be utilized to examine the molecular mechanisms underlying nervous system development. Second, large clutches of developmentally synchronized embryos provide large experimental sample sizes. Third, the optical clarity of the zebrafish embryo permits researchers to visualize progenitor, glial, and neuronal populations. Although zebrafish embryos are transparent, specimen thickness can impede effective microscopic visualization. One reason for this is the tandem development of the spinal cord and overlying somite tissue. Another reason is the large yolk ball, which is still present during periods of early neurogenesis. In this article, we demonstrate microdissection and removal of the yolk in fixed embryos, which allows microscopic visualization while preserving surrounding somite tissue. We also demonstrate semipermanent mounting of zebrafish embryos. This permits observation of neurodevelopment in the dorso-ventral and anterior-posterior axes, as it preserves the three-dimensionality of the tissue.
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28
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Ferg M, Armant O, Yang L, Dickmeis T, Rastegar S, Strähle U. Gene transcription in the zebrafish embryo: regulators and networks. Brief Funct Genomics 2013; 13:131-43. [PMID: 24152666 DOI: 10.1093/bfgp/elt044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The precise spatial and temporal control of gene expression is a key process in the development, maintenance and regeneration of the vertebrate body. A substantial proportion of vertebrate genomes encode genes that control the transcription of the genetic information into mRNA. The zebrafish is particularly well suited to investigate gene regulatory networks underlying the control of gene expression during development due to the external development of its transparent embryos and the increasingly sophisticated tools for genetic manipulation available for this model system. We review here recent data on the analysis of cis-regulatory modules, transcriptional regulators and their integration into gene regulatory networks in the zebrafish, using the developing spinal cord as example.
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Affiliation(s)
- Marco Ferg
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021 Karlsruhe, Germany.
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29
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Francius C, Harris A, Rucchin V, Hendricks TJ, Stam FJ, Barber M, Kurek D, Grosveld FG, Pierani A, Goulding M, Clotman F. Identification of multiple subsets of ventral interneurons and differential distribution along the rostrocaudal axis of the developing spinal cord. PLoS One 2013; 8:e70325. [PMID: 23967072 PMCID: PMC3744532 DOI: 10.1371/journal.pone.0070325] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 06/17/2013] [Indexed: 01/06/2023] Open
Abstract
The spinal cord contains neuronal circuits termed Central Pattern Generators (CPGs) that coordinate rhythmic motor activities. CPG circuits consist of motor neurons and multiple interneuron cell types, many of which are derived from four distinct cardinal classes of ventral interneurons, called V0, V1, V2 and V3. While significant progress has been made on elucidating the molecular and genetic mechanisms that control ventral interneuron differentiation, little is known about their distribution along the antero-posterior axis of the spinal cord and their diversification. Here, we report that V0, V1 and V2 interneurons exhibit distinct organizational patterns at brachial, thoracic and lumbar levels of the developing spinal cord. In addition, we demonstrate that each cardinal class of ventral interneurons can be subdivided into several subsets according to the combinatorial expression of different sets of transcription factors, and that these subsets are differentially distributed along the rostrocaudal axis of the spinal cord. This comprehensive molecular profiling of ventral interneurons provides an important resource for investigating neuronal diversification in the developing spinal cord and for understanding the contribution of specific interneuron subsets on CPG circuits and motor control.
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Affiliation(s)
- Cédric Francius
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
| | - Audrey Harris
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
| | - Vincent Rucchin
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
| | - Timothy J. Hendricks
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Floor J. Stam
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Melissa Barber
- CNRS UMR 7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Dorota Kurek
- Erasmus MC Stem Cell Institute, Department of Cell Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Frank G. Grosveld
- Erasmus MC Stem Cell Institute, Department of Cell Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Alessandra Pierani
- CNRS UMR 7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Frédéric Clotman
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
- * E-mail:
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30
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Lara-Ramírez R, Zieger E, Schubert M. Retinoic acid signaling in spinal cord development. Int J Biochem Cell Biol 2013; 45:1302-13. [PMID: 23579094 DOI: 10.1016/j.biocel.2013.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 03/25/2013] [Accepted: 04/02/2013] [Indexed: 12/13/2022]
Abstract
Retinoic acid (RA) is an important signaling molecule mediating intercellular communication through vertebrate development. Here, we present and discuss recent information on the roles of the RA signaling pathway in spinal cord development. RA is an important player in the patterning and definition of the spinal cord territory from very early stages of development, even before the appearance of the neural plate and further serves a role in the patterning of the spinal cord both along the dorsoventral and anteroposterior axes, particularly in the promotion of neuronal differentiation. It is thus required to establish a variety of neuronal cell types at specific positions of the spinal cord. The main goal of this review is to gather information from vertebrate models, including fish, frogs, chicken and mice, and to put this information in a comparative context in an effort to visualize how the RA pathway was incorporated into the evolving vertebrate spinal cord and to identify mechanisms that are both common and different in the various vertebrate models. In doing so, we try to reconstruct how spinal cord development has been regulated by the RA signaling cascade through vertebrate diversification, highlighting areas which require further studies to obtain a better understanding of the evolutionary events that shaped this structure in the vertebrate lineage.
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Affiliation(s)
- Ricardo Lara-Ramírez
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, UMR 7009 - CNRS/UPMC, EvoInSiDe Team, Observatoire Océanologique, 181 Chemin du Lazaret, BP 28, 06230 Villefranche-sur-Mer, France
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31
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Mich JK, Chen JK. Hedgehog and retinoic acid signaling cooperate to promote motoneurogenesis in zebrafish. Development 2012; 138:5113-9. [PMID: 22069185 DOI: 10.1242/dev.066225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The precise requirements of Hedgehog (Hh) pathway activity in vertebrate central nervous system development remain unclear, particularly in organisms with both maternally and zygotically derived signaling. Here we describe the motoneural phenotype of zebrafish that lack maternal and zygotic contributions of the Hh signaling transducer Smoothened (MZsmo mutants) and therefore are completely devoid of ligand-dependent pathway activation. Some functional primary motoneurons (PMNs) persist in the absence of Hh signaling, and we find that their induction requires both basal Gli transcription factor activity and retinoic acid (RA) signaling. We also provide evidence that RA pathway activation can modulate Gli function in a Hh ligand-independent manner. These findings support a model in which Hh and RA signaling cooperate to promote PMN cell fates in zebrafish.
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Affiliation(s)
- John K Mich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA.
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