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Kandemir B, Kurnaz IA. The Role of Pea3 Transcription Factor Subfamily in the Nervous System. Mol Neurobiol 2024:10.1007/s12035-024-04432-w. [PMID: 39269548 DOI: 10.1007/s12035-024-04432-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 08/08/2024] [Indexed: 09/15/2024]
Abstract
ETS domain transcription factor superfamily is highly conserved throughout metazoa and is involved in many aspects of development and tissue morphogenesis, and as such, the deregulation of ETS proteins is quite common in many diseases, including cancer. The PEA3 subfamily in particular has been extensively studied with respect to tumorigenesis and metastasis; however, they are also involved in the development of many tissues with branching morphogenesis, such as lung or kidney development. In this review, we aim to summarize findings from various studies on the role of Pea3 subfamily members in nervous system development in the embryo, as well as their functions in the adult neurons. We further discuss the different signals that were shown to regulate the function of the Pea3 family and indicate how this signal-dependent regulation of Pea3 proteins can generate neuronal circuit specificity through unique gene regulation. Finally, we discuss how these developmental roles of Pea3 proteins relate to their role in tumorigenesis.
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Affiliation(s)
- Basak Kandemir
- Department of Molecular Biology and Genetics, Baskent University, 06790, Etimesgut, Ankara, Turkey
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Isil Aksan Kurnaz
- Department of Molecular Biology and Genetics, Molecular Neurobiology Laboratory (AxanLab), Gebze Technical University, 41400, Gebze, Kocaeli, Turkey.
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2
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Kang Y, Saito M, Toyoda H. Molecular, Morphological and Electrophysiological Differences between Alpha and Gamma Motoneurons with Special Reference to the Trigeminal Motor Nucleus of Rat. Int J Mol Sci 2024; 25:5266. [PMID: 38791305 PMCID: PMC11121624 DOI: 10.3390/ijms25105266] [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: 04/15/2024] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024] Open
Abstract
The muscle contraction during voluntary movement is controlled by activities of alpha- and gamma-motoneurons (αMNs and γMNs, respectively). In spite of the recent advances in research on molecular markers that can distinguish between αMNs and γMNs, electrophysiological membrane properties and firing patterns of γMNs have remained unknown, while those of αMNs have been clarified in detail. Because of the larger size of αMNs compared to γMNs, blindly or even visually recorded MNs were mostly αMNs, as demonstrated with molecular markers recently. Subsequently, the research on αMNs has made great progress in classifying their subtypes based on the molecular markers and electrophysiological membrane properties, whereas only a few studies demonstrated the electrophysiological membrane properties of γMNs. In this review article, we provide an overview of the recent advances in research on the classification of αMNs and γMNs based on molecular markers and electrophysiological membrane properties, and discuss their functional implication and significance in motor control.
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Affiliation(s)
- Youngnam Kang
- Department of Behavioral Physiology, Graduate School of Human Sciences, Osaka University, Osaka 565-0871, Japan
| | - Mitsuru Saito
- Department of Oral Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima 890-8544, Japan;
| | - Hiroki Toyoda
- Department of Oral Physiology, Graduate School of Dentistry, The University of Osaka, Osaka 565-0871, Japan
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3
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Desiderio S, Schwaller F, Tartour K, Padmanabhan K, Lewin GR, Carroll P, Marmigere F. Touch receptor end-organ innervation and function require sensory neuron expression of the transcription factor Meis2. eLife 2024; 12:RP89287. [PMID: 38386003 PMCID: PMC10942617 DOI: 10.7554/elife.89287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024] Open
Abstract
Touch sensation is primarily encoded by mechanoreceptors, called low-threshold mechanoreceptors (LTMRs), with their cell bodies in the dorsal root ganglia. Because of their great diversity in terms of molecular signature, terminal endings morphology, and electrophysiological properties, mirroring the complexity of tactile experience, LTMRs are a model of choice to study the molecular cues differentially controlling neuronal diversification. While the transcriptional codes that define different LTMR subtypes have been extensively studied, the molecular players that participate in their late maturation and in particular in the striking diversity of their end-organ morphological specialization are largely unknown. Here we identified the TALE homeodomain transcription factor Meis2 as a key regulator of LTMRs target-field innervation in mice. Meis2 is specifically expressed in cutaneous LTMRs, and its expression depends on target-derived signals. While LTMRs lacking Meis2 survived and are normally specified, their end-organ innervations, electrophysiological properties, and transcriptome are differentially and markedly affected, resulting in impaired sensory-evoked behavioral responses. These data establish Meis2 as a major transcriptional regulator controlling the orderly formation of sensory neurons innervating peripheral end organs required for light touch.
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Affiliation(s)
- Simon Desiderio
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM U 1298MontpellierFrance
| | - Frederick Schwaller
- Department of Neuroscience, Max‐Delbrück Centre for Molecular MedicineBerlin‐BuchGermany
| | | | | | - Gary R Lewin
- Department of Neuroscience, Max‐Delbrück Centre for Molecular MedicineBerlin‐BuchGermany
| | - Patrick Carroll
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM U 1298MontpellierFrance
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Ladle DR, Hippenmeyer S. Loss of ETV1/ER81 in motor neurons leads to reduced monosynaptic inputs from proprioceptive sensory neurons. J Neurophysiol 2023; 129:501-512. [PMID: 36695533 DOI: 10.1152/jn.00172.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
Presynaptic inputs determine the pattern of activation of postsynaptic neurons in a neural circuit. Molecular and genetic pathways that regulate the selective formation of subsets of presynaptic inputs are largely unknown, despite significant understanding of the general process of synaptogenesis. In this study, we have begun to identify such factors using the spinal monosynaptic stretch reflex circuit as a model system. In this neuronal circuit, Ia proprioceptive afferents establish monosynaptic connections with spinal motor neurons that project to the same muscle (termed homonymous connections) or muscles with related or synergistic function. However, monosynaptic connections are not formed with motor neurons innervating muscles with antagonistic functions. The ETS transcription factor ER81 (also known as ETV1) is expressed by all proprioceptive afferents, but only a small set of motor neuron pools in the lumbar spinal cord of the mouse. Here we use conditional mouse genetic techniques to eliminate Er81 expression selectively from motor neurons. We find that ablation of Er81 in motor neurons reduces synaptic inputs from proprioceptive afferents conveying information from homonymous and synergistic muscles, with no change observed in the connectivity pattern from antagonistic proprioceptive afferents. In summary, these findings suggest a role for ER81 in defined motor neuron pools to control the assembly of specific presynaptic inputs and thereby influence the profile of activation of these motor neurons.
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Affiliation(s)
- David R Ladle
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
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5
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Single-cell transcriptomic analysis reveals diversity within mammalian spinal motor neurons. Nat Commun 2023; 14:46. [PMID: 36596814 PMCID: PMC9810664 DOI: 10.1038/s41467-022-35574-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Spinal motor neurons (MNs) integrate sensory stimuli and brain commands to generate movements. In vertebrates, the molecular identities of the cardinal MN types such as those innervating limb versus trunk muscles are well elucidated. Yet the identities of finer subtypes within these cell populations that innervate individual muscle groups remain enigmatic. Here we investigate heterogeneity in mouse MNs using single-cell transcriptomics. Among limb-innervating MNs, we reveal a diverse neuropeptide code for delineating putative motor pool identities. Additionally, we uncover that axial MNs are subdivided into three molecularly distinct subtypes, defined by mediolaterally-biased Satb2, Nr2f2 or Bcl11b expression patterns with different axon guidance signatures. These three subtypes are present in chicken and human embryos, suggesting a conserved axial MN expression pattern across higher vertebrates. Overall, our study provides a molecular resource of spinal MN types and paves the way towards deciphering how neuronal subtypes evolved to accommodate vertebrate motor behaviors.
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Ríos AS, Paula De Vincenti A, Casadei M, Aquino JB, Brumovsky PR, Paratcha G, Ledda F. Etv4 regulates nociception by controlling peptidergic sensory neuron development and peripheral tissue innervation. Development 2022; 149:276156. [PMID: 35904071 DOI: 10.1242/dev.200583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/14/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
The perception of noxious environmental stimuli by nociceptive sensory neurons is an essential mechanism for the prevention of tissue damage. Etv4 is a transcriptional factor expressed in most nociceptors in dorsal root ganglia (DRG) during the embryonic development. However, its physiological role remains unclear. Here, we show that Etv4 ablation results in defects in the development of the peripheral peptidergic projections in vivo, and in deficits in axonal elongation and growth cone morphology in cultured sensory neurons in response to NGF. From a mechanistic point of view, our findings reveal that NGF regulates Etv4-dependent gene expression of molecules involved in extracellular matrix (ECM) remodeling. Etv4-null mice were less sensitive to noxious heat stimuli and chemical pain, and this behavioral phenotype correlates with a significant reduction in the expression of the pain-transducing ion channel TRPV1 in mutant mice. Together, our data demonstrate that Etv4 is required for the correct innervation and function of peptidergic sensory neurons, regulating a transcriptional program that involves molecules associated with axonal growth and pain transduction.
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Affiliation(s)
- Antonella S. Ríos
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires 1 , Buenos Aires C1405 BWE, Argentina
| | - Ana Paula De Vincenti
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina. Universidad de Buenos Aires, Buenos Aires (UBA) 2 , Buenos Aires 1121, CP1121 , Argentina
| | - Mailin Casadei
- Instituto de Investigaciones en Medicina Traslacional, CONICET-Universidad Austral 3 , Buenos Aires B1629 ODT, Argentina
| | - Jorge B. Aquino
- Instituto de Investigaciones en Medicina Traslacional, CONICET-Universidad Austral 3 , Buenos Aires B1629 ODT, Argentina
| | - Pablo R. Brumovsky
- Instituto de Investigaciones en Medicina Traslacional, CONICET-Universidad Austral 3 , Buenos Aires B1629 ODT, Argentina
| | - Gustavo Paratcha
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina. Universidad de Buenos Aires, Buenos Aires (UBA) 2 , Buenos Aires 1121, CP1121 , Argentina
| | - Fernanda Ledda
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires 1 , Buenos Aires C1405 BWE, Argentina
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7
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Qi Z, Han S, Wang S, Gu X, Deng J, Huang C, Yin X. Visual three-dimensional spatial distribution of motor neurons innervating superficial limb muscles in mice. Front Cell Neurosci 2022; 16:904172. [PMID: 35936500 PMCID: PMC9354668 DOI: 10.3389/fncel.2022.904172] [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: 03/25/2022] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
The coordination of motor function in the spinal cord depends on selective connections between distinct classes of motor neurons and their target muscles. However, knowledge regarding the anatomical connections between the superficial limb skeletal muscles and the motor neurons that innervate them is limited. In this study, with a combination of the multiple retrograde tracing method with 3DISCO clearing, we explored the spatial distribution of different motor neuron pools targeting specific superficial muscles of the forelimbs or hindlimbs in mouse spinal cords, which were dominated by the radial, median, ulnar, or sciatic nerve. This study reveals the precise interrelationship among different motor neuron pools innervating limb muscles under the same space and time. The data will help to further understand the neural loop and muscular motor coordination.
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Affiliation(s)
- Zhidan Qi
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Shuai Han
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
| | - Shen Wang
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Xinyi Gu
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Jin Deng
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Chen Huang
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Xiaofeng Yin
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
- *Correspondence: Xiaofeng Yin,
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8
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Peek SL, Bosch PJ, Bahl E, Iverson BJ, Parida M, Bais P, Manak JR, Michaelson JJ, Burgess RW, Weiner JA. p53-mediated neurodegeneration in the absence of the nuclear protein Akirin2. iScience 2022; 25:103814. [PMID: 35198879 PMCID: PMC8844820 DOI: 10.1016/j.isci.2022.103814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/04/2022] [Accepted: 01/20/2022] [Indexed: 12/13/2022] Open
Abstract
Proper gene regulation is critical for both neuronal development and maintenance as the brain matures. We previously demonstrated that Akirin2, an essential nuclear protein that interacts with transcription factors and chromatin remodeling complexes, is required for the embryonic formation of the cerebral cortex. Here we show that Akirin2 plays a mechanistically distinct role in maintaining healthy neurons during cortical maturation. Restricting Akirin2 loss to excitatory cortical neurons resulted in progressive neurodegeneration via necroptosis and severe cortical atrophy with age. Comparing transcriptomes from Akirin2-null postnatal neurons and cortical progenitors revealed that targets of the tumor suppressor p53, a regulator of both proliferation and cell death encoded by Trp53, were consistently upregulated. Reduction of Trp53 rescued neurodegeneration in Akirin2-null neurons. These data: (1) implicate Akirin2 as a critical neuronal maintenance protein, (2) identify p53 pathways as mediators of Akirin2 functions, and (3) suggest Akirin2 dysfunction may be relevant to neurodegenerative diseases.
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Affiliation(s)
- Stacey L. Peek
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Peter J. Bosch
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Ethan Bahl
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Brianna J. Iverson
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Mrutyunjaya Parida
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
- Departments of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
- Roy J. Carver Center for Genomics, University of Iowa, Iowa City, IA 52242, USA
| | - Preeti Bais
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - J. Robert Manak
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
- Departments of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
- Roy J. Carver Center for Genomics, University of Iowa, Iowa City, IA 52242, USA
| | - Jacob J. Michaelson
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
- Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, IA 52242, USA
- Department of Communication Sciences and Disorders, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA 52242, USA
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA 52242, USA
| | | | - Joshua A. Weiner
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
- Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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9
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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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10
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Brovkina MV, Duffié R, Burtis AEC, Clowney EJ. Fruitless decommissions regulatory elements to implement cell-type-specific neuronal masculinization. PLoS Genet 2021; 17:e1009338. [PMID: 33600447 PMCID: PMC7924761 DOI: 10.1371/journal.pgen.1009338] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/02/2021] [Accepted: 01/04/2021] [Indexed: 01/12/2023] Open
Abstract
In the fruit fly Drosophila melanogaster, male-specific splicing and translation of the Fruitless transcription factor (FruM) alters the presence, anatomy, and/or connectivity of >60 types of central brain neurons that interconnect to generate male-typical behaviors. While the indispensable function of FruM in sex-specific behavior has been understood for decades, the molecular mechanisms underlying its activity remain unknown. Here, we take a genome-wide, brain-wide approach to identifying regulatory elements whose activity depends on the presence of FruM. We identify 436 high-confidence genomic regions differentially accessible in male fruitless neurons, validate candidate regions as bona fide, differentially regulated enhancers, and describe the particular cell types in which these enhancers are active. We find that individual enhancers are not activated universally but are dedicated to specific fru+ cell types. Aside from fru itself, genes are not dedicated to or common across the fru circuit; rather, FruM appears to masculinize each cell type differently, by tweaking expression of the same effector genes used in other circuits. Finally, we find FruM motifs enriched among regulatory elements that are open in the female but closed in the male. Together, these results suggest that FruM acts cell-type-specifically to decommission regulatory elements in male fruitless neurons. Courtship behavior in male Drosophila melanogaster is controlled by a well-defined neural circuit that is labeled by the male-specific transcription factor Fruitless (FruM). While FruM is known to change the number, anatomy and connectivity of neurons which comprise the circuit and has been suggested to repress the expression of a few gene targets, the mechanism of how FruM regulates genes across many different kinds of neurons is unknown. Using an approach to identify gene regulatory elements based on their chromatin accessibility states (ATAC-seq), we identified a large set of chromatin accessibility changes downstream of Fruitless. By examining the activity of these regulatory elements in vivo, we found that their activity was 1) sexually dimorphic and 2) specific to a single class of FruM neurons, suggesting that FruM acts on different chromatin targets in different neuron classes comprising the courtship circuit. Further, we found a known FruM-regulated enhancer of the FruM-repressed gene Lgr3 to have closed chromatin specifically in FruM neurons. Combined with an enrichment of FruM motifs in regions which are closed in FruM neurons, we present a mechanism where FruM directs the decommissioning of sex-shared regulatory elements to masculinize neurons in a cell-type specific manner.
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Affiliation(s)
- Margarita V. Brovkina
- Graduate Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Rachel Duffié
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
- Mortimer B. Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, New York, United States of America
| | - Abbigayl E. C. Burtis
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, Michigan, United States of America
| | - E. Josephine Clowney
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Luria V, Laufer E. The Geometry of Limb Motor Innervation is Controlled by the Dorsal-Ventral Compartment Boundary in the Chick Limbless Mutant. Neuroscience 2020; 450:29-47. [PMID: 33038447 PMCID: PMC9922539 DOI: 10.1016/j.neuroscience.2020.09.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 11/29/2022]
Abstract
Precise control of limb muscles, and ultimately of limb movement, requires accurate motor innervation. Motor innervation of the vertebrate limb is established by sequential selection of trajectories at successive decision points. Motor axons of the lateral motor column (LMC) segregate at the base of the limb into two groups that execute a choice between dorsal and ventral tissue: medial LMC axons innervate the ventral limb, whereas lateral LMC axons innervate the dorsal limb. We investigated how LMC axons are targeted to the limb using the chick mutant limbless (ll), which has a dorsal transformation of the ventral limb mesenchyme. In ll the spatial pattern of motor projections to the limb is abnormal while their targeting is normal. While extensive, the dorsal transformation of the ll ventral limb mesenchyme is incomplete whereas the generation, specification and targeting of spinal motor neurons are apparently unaffected. Thus, the dorsal-ventral motor axon segregation is an active choice that is independent of the ratio between dorsal and ventral tissue but dependent on the presence of both tissues. Therefore, the fidelity of the motor projections to the limb depends on the presence of both dorsal and ventral compartments, while the geometry of motor projections is controlled by the position of limb dorsal-ventral compartment boundary.
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Affiliation(s)
- Victor Luria
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
| | - Ed Laufer
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA.
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12
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Expression of Pea3 protein subfamily members in hippocampus and potential regulation following neuronal stimulation. Neurosci Lett 2020; 738:135348. [PMID: 32891673 DOI: 10.1016/j.neulet.2020.135348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 02/07/2023]
Abstract
Pea3 proteins belong to a subfamily of the E-twentysix (ETS) domain superfamily of transcription factors, which play various roles during development. Polyoma Enhancer-Activator 3 (Pea3) proteins Pea3, ERM and Er81 are particularly involved in tissues with branching morphogenesis, including kidney, lung, mammary gland and nervous system development. A recent transcriptomic study on novel targets of Pea3 transcription factor revealed various axon guidance and nervous system development related targets, supporting a role of Pea3 proteins in motor neuron connectivity, as well as novel targets in signaling pathways involved in synaptic plasticity. This study focuses on the expression of Pea3 family members in hippocampal neurons, and regulation of putative Pea3 targets in Pea3-overexpressing cell lines and following induction of long-term potentiation or seizure in vivo. We show that Pea3 proteins are expressed in hippocampus in both neuronal and non-neuronal cells, and that Pea3 represses Elk-1 but activates Prkca and Nrcam expression in hippocampal cell lines. We also show that mRNA and protein levels of Pea3 family members are differentially regulated in the dentate gyrus and CA1 region upon MECS stimulation, but not upon LTP induction.
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13
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Kandemir B, Gulfidan G, Arga KY, Yilmaz B, Kurnaz IA. Transcriptomic profile of Pea3 family members reveal regulatory codes for axon outgrowth and neuronal connection specificity. Sci Rep 2020; 10:18162. [PMID: 33097800 PMCID: PMC7584614 DOI: 10.1038/s41598-020-75089-3] [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: 10/28/2019] [Accepted: 09/29/2020] [Indexed: 12/13/2022] Open
Abstract
PEA3 transcription factor subfamily is present in a variety of tissues with branching morphogenesis, and play a particularly significant role in neural circuit formation and specificity. Many target genes in axon guidance and cell-cell adhesion pathways have been identified for Pea3 transcription factor (but not for Erm or Er81); however it was not so far clear whether all Pea3 subfamily members regulate same target genes, or whether there are unique targets for each subfamily member that help explain the exclusivity and specificity of these proteins in neuronal circuit formation. In this study, using transcriptomics and qPCR analyses in SH-SY5Y neuroblastoma cells, hypothalamic and hippocampal cell line, we have identified cell type-specific and subfamily member-specific targets for PEA3 transcription factor subfamily. While Pea3 upregulates transcription of Sema3D and represses Sema5B, for example, Erm and Er81 upregulate Sema5A and Er81 regulates Unc5C and Sema4G while repressing EFNB3 in SH-SY5Y neuroblastoma cells. We furthermore present a molecular model of how unique sites within the ETS domain of each family member can help recognize specific target motifs. Such cell-context and member-specific combinatorial expression profiles help identify cell-cell and cell-extracellular matrix communication networks and how they establish specific connections.
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Affiliation(s)
- Başak Kandemir
- Institute of Biotechnology, Gebze Technical University, Kocaeli, Turkey
- Biotechnology Graduate Program, Yeditepe University, Kayisdagi, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Baskent University, Ankara, Turkey
| | - Gizem Gulfidan
- Department of Bioengineering, Marmara University, Goztepe, Istanbul, Turkey
| | - Kazim Yalcin Arga
- Department of Bioengineering, Marmara University, Goztepe, Istanbul, Turkey
| | - Bayram Yilmaz
- Biotechnology Graduate Program, Yeditepe University, Kayisdagi, Istanbul, Turkey
- Faculty of Medicine, Yeditepe University, Kayisdagi, Istanbul, Turkey
| | - Isil Aksan Kurnaz
- Institute of Biotechnology, Gebze Technical University, Kocaeli, Turkey.
- Department of Molecular Biology and Genetics, Gebze Technical University, Kocaeli, Turkey.
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14
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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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15
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Harris JM, Wang AYD, Boulanger-Weill J, Santoriello C, Foianini S, Lichtman JW, Zon LI, Arlotta P. Long-Range Optogenetic Control of Axon Guidance Overcomes Developmental Boundaries and Defects. Dev Cell 2020; 53:577-588.e7. [PMID: 32516597 PMCID: PMC7375170 DOI: 10.1016/j.devcel.2020.05.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 03/12/2020] [Accepted: 05/11/2020] [Indexed: 01/12/2023]
Abstract
Axons connect neurons together, establishing the wiring architecture of neuronal networks. Axonal connectivity is largely built during embryonic development through highly constrained processes of axon guidance, which have been extensively studied. However, the inability to control axon guidance, and thus neuronal network architecture, has limited investigation of how axonal connections influence subsequent development and function of neuronal networks. Here, we use zebrafish motor neurons expressing a photoactivatable Rac1 to co-opt endogenous growth cone guidance machinery to precisely and non-invasively direct axon growth using light. Axons can be guided over large distances, within complex environments of living organisms, overriding competing endogenous signals and redirecting axons across potent repulsive barriers to construct novel circuitry. Notably, genetic axon guidance defects can be rescued, restoring functional connectivity. These data demonstrate that intrinsic growth cone guidance machinery can be co-opted to non-invasively build new connectivity, allowing investigation of neural network dynamics in intact living organisms.
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Affiliation(s)
- James M. Harris
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Harvard-MIT Division of Health Sciences and Technology, Harvard Medical School, Boston, MA 02115, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA
| | - Andy Yu-Der Wang
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Current Address: Tufts University School of Medicine, Boston, MA 02115, USA
| | - Jonathan Boulanger-Weill
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Cristina Santoriello
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Stem Cell Program and Division of Hematology/Oncology, Children’s Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Medical School, Harvard Stem Cell Institute, Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA
| | - Stephan Foianini
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jeff W. Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Leonard I. Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Stem Cell Program and Division of Hematology/Oncology, Children’s Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Medical School, Harvard Stem Cell Institute, Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA
| | - Paola Arlotta
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA.,Lead contact. Correspondence:
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16
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Toch M, Harris A, Schakman O, Kondratskaya E, Boulland JL, Dauguet N, Debrulle S, Baudouin C, Hidalgo-Figueroa M, Mu X, Gow A, Glover JC, Tissir F, Clotman F. Onecut-dependent Nkx6.2 transcription factor expression is required for proper formation and activity of spinal locomotor circuits. Sci Rep 2020; 10:996. [PMID: 31969659 PMCID: PMC6976625 DOI: 10.1038/s41598-020-57945-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/09/2020] [Indexed: 11/26/2022] Open
Abstract
In the developing spinal cord, Onecut transcription factors control the diversification of motor neurons into distinct neuronal subsets by ensuring the maintenance of Isl1 expression during differentiation. However, other genes downstream of the Onecut proteins and involved in motor neuron diversification have remained unidentified. In the present study, we generated conditional mutant embryos carrying specific inactivation of Onecut genes in the developing motor neurons, performed RNA-sequencing to identify factors downstream of Onecut proteins in this neuron population, and employed additional transgenic mouse models to assess the role of one specific Onecut-downstream target, the transcription factor Nkx6.2. Nkx6.2 expression was up-regulated in Onecut-deficient motor neurons, but strongly downregulated in Onecut-deficient V2a interneurons, indicating an opposite regulation of Nkx6.2 by Onecut factors in distinct spinal neuron populations. Nkx6.2-null embryos, neonates and adult mice exhibited alterations of locomotor pattern and spinal locomotor network activity, likely resulting from defective survival of a subset of limb-innervating motor neurons and abnormal migration of V2a interneurons. Taken together, our results indicate that Nkx6.2 regulates the development of spinal neuronal populations and the formation of the spinal locomotor circuits downstream of the Onecut transcription factors.
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Affiliation(s)
- Mathilde Toch
- 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
| | - Olivier Schakman
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Cell Physiology, Brussels, Belgium
| | - Elena Kondratskaya
- Laboratory for Neural Development and Optical Recording (NDEVOR), Section for Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Jean-Luc Boulland
- Norwegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Nicolas Dauguet
- Université catholique de Louvain, de Duve Institute, Flow cytometry and cell sorting facility (CYTF), Brussels, Belgium
| | - Stéphanie Debrulle
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
| | - Charlotte Baudouin
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
| | - Maria Hidalgo-Figueroa
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium.,CIBER de Salud Mental (CIBERSAM), Madrid, Spain.,University of Cadiz, Cadiz, Spain
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Alexander Gow
- Wayne state University, Center for Molecular Medicine and Genetics, Carman and Ann Adams Department of Pediatrics, Department of Neurology, Detroit, Michigan, USA
| | - Joel C Glover
- Laboratory for Neural Development and Optical Recording (NDEVOR), Section for Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Norwegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Fadel Tissir
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Developmental Neurobiology, Brussels, Belgium
| | - Frédéric Clotman
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium.
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17
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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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18
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Abstract
ABSTRACT
Thomas M. Jessell died on April 28, 2019. Tom revolutionized our understanding of the mechanisms through which neuronal cell type identities are programmed during development to dictate their function in the adult nervous system. Here, we (two former postdocs from his lab) remember some of his most important scientific contributions and how these changed the way we now understand and think about neuronal circuits controlling movement.
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Affiliation(s)
- Silvia Arber
- Biozentrum, Department of Cell Biology, University of Basel, 4056 Basel, Switzerland
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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19
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Aggarwal RR, Quigley DA, Huang J, Zhang L, Beer TM, Rettig MB, Reiter RE, Gleave ME, Thomas GV, Foye A, Playdle D, Lloyd P, Chi KN, Evans CP, Lara PN, Feng FY, Alumkal JJ, Small EJ. Whole-Genome and Transcriptional Analysis of Treatment-Emergent Small-Cell Neuroendocrine Prostate Cancer Demonstrates Intraclass Heterogeneity. Mol Cancer Res 2019; 17:1235-1240. [PMID: 30918106 DOI: 10.1158/1541-7786.mcr-18-1101] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/09/2018] [Accepted: 03/22/2019] [Indexed: 11/16/2022]
Abstract
Therapeutic resistance in metastatic castration-resistant prostate cancer (mCRPC) can be accompanied by treatment-emergent small-cell neuroendocrine carcinoma (t-SCNC), a morphologically distinct subtype. We performed integrative whole-genome and -transcriptome analysis of mCRPC tumor biopsies including paired biopsies after progression, and multiple samples from the same individual. t-SCNC was significantly less likely to have amplification of AR or an intergenic AR-enhancer locus, and demonstrated lower expression of AR and its downstream transcriptional targets. Genomic and transcriptional hallmarks of t-SCNC included biallelic loss of RB1, elevated expression levels of CDKN2A and E2F1, and loss of expression of the AR and AR-responsive genes including TMPRSS2 and NKX3-1. We identified three tumors that converted from adenocarcinoma to t-SCNC and demonstrate spatial and temporal intrapatient heterogeneity of metastatic tumors harboring adenocarcinoma, t-SCNC, or mixed expression phenotypes, with implications for treatment strategies in which dual targeting of adenocarcinoma and t-SCNC phenotypes may be necessary. IMPLICATIONS: The t-SCNC phenotype is characterized by lack of AR enhancer gain and loss of RB1 function, and demonstrates both interindividual and intraindividual heterogeneity.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/6/1235/F1.large.jpg.
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Affiliation(s)
- Rahul R Aggarwal
- University of California San Francisco, San Francisco, California.
| | - David A Quigley
- University of California San Francisco, San Francisco, California
| | | | - Li Zhang
- University of California San Francisco, San Francisco, California
| | - Tomasz M Beer
- Oregon Health & Science University, Portland, Oregon
| | | | - Rob E Reiter
- University of California Los Angeles, Los Angeles, California
| | - Martin E Gleave
- Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Adam Foye
- University of California San Francisco, San Francisco, California
| | - Denise Playdle
- University of California San Francisco, San Francisco, California
| | - Paul Lloyd
- University of California San Francisco, San Francisco, California
| | - Kim N Chi
- Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Primo N Lara
- University of California Davis, Davis, California
| | - Felix Y Feng
- University of California San Francisco, San Francisco, California
| | | | - Eric J Small
- University of California San Francisco, San Francisco, California
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20
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Fontanet PA, Ríos AS, Alsina FC, Paratcha G, Ledda F. Pea3 Transcription Factors, Etv4 and Etv5, Are Required for Proper Hippocampal Dendrite Development and Plasticity. Cereb Cortex 2018; 28:236-249. [PMID: 27909004 DOI: 10.1093/cercor/bhw372] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Indexed: 12/19/2022] Open
Abstract
The proper formation and morphogenesis of dendrites is essential to the establishment of neuronal connectivity. We report that 2 members of the Pea3 family of transcription factors, Etv4 and Etv5, are expressed in hippocampal neurons during the main period of dendritogenesis, suggesting that they have a function in dendrite development. Here, we show that these transcription factors are physiological regulators of growth and arborization of pyramidal cell dendrites in the developing hippocampus. Gain and loss of function assays indicate that Etv4 and Etv5 are required for proper development of hippocampal dendritic arbors and spines. We have found that in vivo deletion of either Etv4 or Etv5 in hippocampal neurons causes deficits in dendrite size and complexity, which are associated with impaired cognitive function. Additionally, our data support the idea that Etv4 and Etv5 are part of a brain-derived neurotrophic factor-mediated transcriptional program required for proper hippocampal dendrite connectivity and plasticity.
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Affiliation(s)
- Paula Aldana Fontanet
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine. University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Antonella Soledad Ríos
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine. University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Fernando Cruz Alsina
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine. University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Gustavo Paratcha
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine. University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Fernanda Ledda
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine. University of Buenos Aires (UBA), Buenos Aires, Argentina
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21
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Nishimura K, Ohta M, Saito M, Morita-Isogai Y, Sato H, Kuramoto E, Yin DX, Maeda Y, Kaneko T, Yamashiro T, Takada K, Oh SB, Toyoda H, Kang Y. Electrophysiological and Morphological Properties of α and γ Motoneurons in the Rat Trigeminal Motor Nucleus. Front Cell Neurosci 2018; 12:9. [PMID: 29416504 PMCID: PMC5787551 DOI: 10.3389/fncel.2018.00009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/08/2018] [Indexed: 11/18/2022] Open
Abstract
The muscle contraction during voluntary movement is regulated by activities of α- and γ-motoneurons (αMNs and γMNs, respectively). The tension of jaw-closing muscles can be finely tuned over a wide range. This excellent function is likely to be achieved by the specific populations of αMNs innervating jaw-closing muscles. Indeed, we have recently demonstrated that in the rat dorsolateral trigeminal motor nucleus (dl-TMN), the size distribution of αMNs was bimodal and the population of smaller αMNs showed a size distribution similar to that of γMNs, by immunohistochemically identifying αMNs and γMNs based on the expressions of estrogen-related receptor gamma (Err3) and neuronal DNA binding protein NeuN together with ChAT. This finding suggests the presence of αMNs as small as γMNs. However, differences in the electrophysiological membrane properties between αMNs and γMNs remain unknown also in the dl-TMN. Therefore, in the present study, we studied the electrophysiological membrane properties of MNs in the dl-TMN of infant rats at postnatal days 7–12 together with their morphological properties using whole-cell current-clamp recordings followed by immunohistochemical staining with an anti-NeuN and anti-ChAT antibodies. We found that the ChAT-positive and NeuN-positive αMNs were divided into two subclasses: the first one had a larger cell body and displayed a 4-aminopyridine (4-AP)-sensitive current while the second one had a smaller cell body and displayed a less prominent 4-AP-sensitive current and a low-threshold spike, suitable for their orderly recruitment. We finally found that γMNs showing ChAT-positive and NeuN-negative immunoreactivities had smaller cell bodies and displayed an afterdepolarization mediated by flufenamate-sensitive cation current. It is suggested that these electrophysiological and morphological features of MNs in the dl-TMN are well correlated with the precise control of occlusion.
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Affiliation(s)
- Kayo Nishimura
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan.,Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Masahiro Ohta
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan.,Department of Removable Prosthodontics, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Mitsuru Saito
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan.,Department of Oral Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yukako Morita-Isogai
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan.,Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Hajime Sato
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Eriko Kuramoto
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.,Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Dong Xu Yin
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Yoshinobu Maeda
- Department of Removable Prosthodontics, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Takeshi Kaneko
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Yamashiro
- Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Kenji Takada
- Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Seog Bae Oh
- Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Hiroki Toyoda
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Youngnam Kang
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan.,Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, South Korea
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22
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Dewitz C, Pimpinella S, Hackel P, Akalin A, Jessell TM, Zampieri N. Nuclear Organization in the Spinal Cord Depends on Motor Neuron Lamination Orchestrated by Catenin and Afadin Function. Cell Rep 2018; 22:1681-1694. [DOI: 10.1016/j.celrep.2018.01.059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 12/19/2017] [Accepted: 01/18/2018] [Indexed: 01/08/2023] Open
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23
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Hayashi M, Hinckley CA, Driscoll SP, Moore NJ, Levine AJ, Hilde KL, Sharma K, Pfaff SL. Graded Arrays of Spinal and Supraspinal V2a Interneuron Subtypes Underlie Forelimb and Hindlimb Motor Control. Neuron 2018; 97:869-884.e5. [PMID: 29398364 PMCID: PMC8601153 DOI: 10.1016/j.neuron.2018.01.023] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 12/04/2017] [Accepted: 01/10/2018] [Indexed: 01/13/2023]
Abstract
The spinal cord contains neural networks that enable regionally distinct motor outputs along the body axis. Nevertheless, it remains unclear how segment-specific motor computations are processed because the cardinal interneuron classes that control motor neurons appear uniform at each level of the spinal cord. V2a interneurons are essential to both forelimb and hindlimb movements, and here we identify two major types that emerge during development: type I neurons marked by high Chx10 form recurrent networks with neighboring spinal neurons and type II neurons that downregulate Chx10 and project to supraspinal structures. Types I and II V2a interneurons are arrayed in counter-gradients, and this network activates different patterns of motor output at cervical and lumbar levels. Single-cell RNA sequencing (RNA-seq) revealed type I and II V2a neurons are each comprised of multiple subtypes. Our findings uncover a molecular and anatomical organization of V2a interneurons reminiscent of the orderly way motor neurons are divided into columns and pools.
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Affiliation(s)
- Marito Hayashi
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA; Biological Sciences Graduate Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92037, USA
| | - Christopher A Hinckley
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Shawn P Driscoll
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Niall J Moore
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Ariel J Levine
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Kathryn L Hilde
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Kamal Sharma
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, 808 South Wood Street, Chicago, IL 60612, USA
| | - Samuel L Pfaff
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA.
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24
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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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25
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Gezelius H, Moreno-Juan V, Mezzera C, Thakurela S, Rodríguez-Malmierca LM, Pistolic J, Benes V, Tiwari VK, López-Bendito G. Genetic Labeling of Nuclei-Specific Thalamocortical Neurons Reveals Putative Sensory-Modality Specific Genes. Cereb Cortex 2017; 27:5054-5069. [PMID: 27655933 PMCID: PMC7610997 DOI: 10.1093/cercor/bhw290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/22/2016] [Indexed: 11/14/2022] Open
Abstract
The thalamus is a central brain structure with topographically ordered long-range axonal projections that convey sensory information to the cortex via distinct nuclei. Although there is an increasing knowledge about genes important for thalamocortical (TC) development, the identification of genetic landmarks of the distinct thalamic nuclei during the embryonic development has not been addressed systematically. Indeed, a more comprehensive understanding of how the axons from the individual nuclei find their way and connect to their corresponding cortical area is called for. Here, we used a genetic dual labeling strategy in mice to purify distinct principal sensory thalamic neurons. Subsequent genome-wide transcriptome profiling revealed genes specifically expressed in each nucleus during embryonic development. Analysis of regulatory regions of the identified genes revealed key transcription factors and networks that likely underlie the specification of individual sensory-modality TC connections. Finally, the importance of correct axon targeting for the specific sensory-modality population transcriptome was evidenced in a Sema6A mutant, in which visual TC axons are derailed at embryonic life. In sum, our data determined the developmental transcriptional profile of the TC neurons that will eventually support sensory processing.
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Affiliation(s)
- Henrik Gezelius
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, 03550, Spain
| | - Verónica Moreno-Juan
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, 03550, Spain
| | - Cecilia Mezzera
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, 03550, Spain
- Present address: Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, 1400-038 Lisbon, Portugal
| | - Sudhir Thakurela
- Institute of Molecular Biology (IMB), Ackermannweg 4, D-55128 Mainz, Germany
| | - Luis Miguel Rodríguez-Malmierca
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, 03550, Spain
| | | | - Vladimir Benes
- EMBL, GeneCore, Meyerhofstr. 1, D-69117 Heidelberg, Germany
| | - Vijay K. Tiwari
- Institute of Molecular Biology (IMB), Ackermannweg 4, D-55128 Mainz, Germany
| | - Guillermina López-Bendito
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, 03550, Spain
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26
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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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In silico analyses and global transcriptional profiling reveal novel putative targets for Pea3 transcription factor related to its function in neurons. PLoS One 2017; 12:e0170585. [PMID: 28158215 PMCID: PMC5291419 DOI: 10.1371/journal.pone.0170585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 01/08/2017] [Indexed: 01/05/2023] Open
Abstract
Pea3 transcription factor belongs to the PEA3 subfamily within the ETS domain transcription factor superfamily, and has been largely studied in relation to its role in breast cancer metastasis. Nonetheless, Pea3 plays a role not only in breast tumor, but also in other tissues with branching morphogenesis, including kidneys, blood vasculature, bronchi and the developing nervous system. Identification of Pea3 target promoters in these systems are important for a thorough understanding of how Pea3 functions. Present study particularly focuses on the identification of novel neuronal targets of Pea3 in a combinatorial approach, through curation, computational analysis and microarray studies in a neuronal model system, SH-SY5Y neuroblastoma cells. We not only show that quite a number of genes in cancer, immune system and cell cycle pathways, among many others, are either up- or down-regulated by Pea3, but also identify novel targets including ephrins and ephrin receptors, semaphorins, cell adhesion molecules, as well as metalloproteases such as kallikreins, to be among potential target promoters in neuronal systems. Our overall results indicate that rather than early stages of neurite extension and axonal guidance, Pea3 is more involved in target identification and synaptic maturation.
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28
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Dasen JS. Master or servant? emerging roles for motor neuron subtypes in the construction and evolution of locomotor circuits. Curr Opin Neurobiol 2017; 42:25-32. [PMID: 27907815 PMCID: PMC5316365 DOI: 10.1016/j.conb.2016.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/05/2016] [Accepted: 11/13/2016] [Indexed: 01/23/2023]
Abstract
Execution of motor behaviors relies on the ability of circuits within the nervous system to engage functionally relevant subtypes of spinal motor neurons. While much attention has been given to the role of networks of spinal interneurons on setting the rhythm and pattern of output from locomotor circuits, recent studies suggest that motor neurons themselves can exert an instructive role in shaping the wiring and functional properties of locomotor networks. Alteration in the distribution of motor neuron subtypes also appears to have contributed to evolutionary transitions in the locomotor strategies used by land vertebrates. This review describes emerging evidence that motor neuron-derived cues can have a profound influence on the organization, wiring, and evolutionary diversification of locomotor circuits.
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Affiliation(s)
- 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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Diodato A, Ruinart de Brimont M, Yim YS, Derian N, Perrin S, Pouch J, Klatzmann D, Garel S, Choi GB, Fleischmann A. Molecular signatures of neural connectivity in the olfactory cortex. Nat Commun 2016; 7:12238. [PMID: 27426965 PMCID: PMC4960301 DOI: 10.1038/ncomms12238] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 06/14/2016] [Indexed: 01/01/2023] Open
Abstract
The ability to target subclasses of neurons with defined connectivity is crucial for uncovering neural circuit functions. The olfactory (piriform) cortex is thought to generate odour percepts and memories, and odour information encoded in piriform is routed to target brain areas involved in multimodal sensory integration, cognition and motor control. However, it remains unknown if piriform outputs are spatially organized, and if distinct output channels are delineated by different gene expression patterns. Here we identify genes selectively expressed in different layers of the piriform cortex. Neural tracing experiments reveal that these layer-specific piriform genes mark different subclasses of neurons, which project to distinct target areas. Interestingly, these molecular signatures of connectivity are maintained in reeler mutant mice, in which neural positioning is scrambled. These results reveal that a predictive link between a neuron's molecular identity and connectivity in this cortical circuit is determined independent of its spatial position. The piriform cortex projects to multiple brain regions involved in diverse aspects of olfactory behavior but information about the organization of these outputs is lacking. Here the authors show that piriform neurons exhibit layer specific gene expression patterns that also define distinct projection targets.
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Affiliation(s)
- Assunta Diodato
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, and CNRS, UMR 7241 and INSERM U1050, F-75005 Paris, France
| | - Marion Ruinart de Brimont
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, and CNRS, UMR 7241 and INSERM U1050, F-75005 Paris, France
| | - Yeong Shin Yim
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Nicolas Derian
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U959, Immunology-Immunopathology-Immunotherapy (I3), and AP-HP, Clinical Investigation Center in Biotherapy, Hôpital Pitié-Salpêtrière, F-75013 Paris, France
| | - Sandrine Perrin
- École Normale Supérieure, Institut de Biologie de l'ENS, Plateforme Génomique, and INSERM U1024, CNRS UMR 8197, F-75005 Paris, France
| | - Juliette Pouch
- École Normale Supérieure, Institut de Biologie de l'ENS, Plateforme Génomique, and INSERM U1024, CNRS UMR 8197, F-75005 Paris, France
| | - David Klatzmann
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U959, Immunology-Immunopathology-Immunotherapy (I3), and AP-HP, Clinical Investigation Center in Biotherapy, Hôpital Pitié-Salpêtrière, F-75013 Paris, France
| | - Sonia Garel
- École Normale Supérieure, Institut de Biologie de l'ENS, and INSERM U1024, CNRS UMR 8197, F-75005 Paris, France
| | - Gloria B Choi
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Alexander Fleischmann
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, and CNRS, UMR 7241 and INSERM U1050, F-75005 Paris, France
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30
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Abstract
Whole-genome sequencing of wild-derived rat species can provide novel genomic resources, which may help decipher the genetics underlying complex phenotypes. As a notorious pest, reservoir of human pathogens, and colonizer, the Asian house rat, Rattus tanezumi, is successfully adapted to its habitat. However, little is known regarding genetic variation in this species. In this study, we identified over 41,000,000 single-nucleotide polymorphisms, plus insertions and deletions, through whole-genome sequencing and bioinformatics analyses. Moreover, we identified over 12,000 structural variants, including 143 chromosomal inversions. Further functional analyses revealed several fixed nonsense mutations associated with infection and immunity-related adaptations, and a number of fixed missense mutations that may be related to anticoagulant resistance. A genome-wide scan for loci under selection identified various genes related to neural activity. Our whole-genome sequencing data provide a genomic resource for future genetic studies of the Asian house rat species and have the potential to facilitate understanding of the molecular adaptations of rats to their ecological niches.
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31
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Nelson BR, Matsuhashi S, Lefcort F. Restricted neural epidermal growth factor-like like 2 (NELL2) expression during muscle and neuronal differentiation. Mech Dev 2016; 119 Suppl 1:S11-9. [PMID: 14516654 DOI: 10.1016/s0925-4773(03)00084-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have identified a secreted glycoprotein, neural epidermal growth factor-like like 2 (NELL2), in a screen designed to isolate molecules regulating sensory neuron genesis and differentiation in the dorsal root ganglia (DRG). In investigating NELL2 expression during embryogenesis, we demonstrate here that NELL2 is highly regulated spatially and temporally, being only transiently expressed in discrete regions of the central (CNS) and peripheral nervous systems (PNS) and in a subset of mesoderm derived structures during their peak periods of development. In the CNS and PNS, NELL2 is maximally expressed as motor and sensory neurons differentiate. Interestingly, its expression is restricted to sublineages of the neural crest, being strongly expressed throughout the immature DRG, but excluded from sympathetic ganglia. Similarly during muscle development, NELL2 is specifically expressed by hypaxial muscle precursor cells in the differentiating somite and derivatives in the forelimbs and body wall, but not by epaxial muscle precursors. Furthermore, NELL2 is differentially regulated in the CNS and PNS; in the CNS, NELL2 is only expressed by nascent, post-mitotic neurons as they commence their differentiation, yet in the PNS, NELL2 is expressed by subsets of progenitor cells in addition to nascent neurons. Based on this restricted spatial and temporal expression pattern, functional studies are in progress to determine NELL2's role during neuronal differentiation in both the PNS and CNS.
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Affiliation(s)
- Branden R Nelson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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32
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Siembab VC, Gomez-Perez L, Rotterman TM, Shneider NA, Alvarez FJ. Role of primary afferents in the developmental regulation of motor axon synapse numbers on Renshaw cells. J Comp Neurol 2016; 524:1892-919. [PMID: 26660356 DOI: 10.1002/cne.23946] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 01/21/2023]
Abstract
Motor function in mammalian species depends on the maturation of spinal circuits formed by a large variety of interneurons that regulate motoneuron firing and motor output. Interneuron activity is in turn modulated by the organization of their synaptic inputs, but the principles governing the development of specific synaptic architectures unique to each premotor interneuron are unknown. For example, Renshaw cells receive, at least in the neonate, convergent inputs from sensory afferents (likely Ia) and motor axons, raising the question of whether they interact during Renshaw cell development. In other well-studied neurons, such as Purkinje cells, heterosynaptic competition between inputs from different sources shapes synaptic organization. To examine the possibility that sensory afferents modulate synaptic maturation on developing Renshaw cells, we used three animal models in which afferent inputs in the ventral horn are dramatically reduced (ER81(-/-) knockout), weakened (Egr3(-/-) knockout), or strengthened (mlcNT3(+/-) transgenic). We demonstrate that increasing the strength of sensory inputs on Renshaw cells prevents their deselection and reduces motor axon synaptic density, and, in contrast, absent or diminished sensory afferent inputs correlate with increased densities of motor axons synapses. No effects were observed on other glutamatergic inputs. We conclude that the early strength of Ia synapses influences their maintenance or weakening during later development and that heterosynaptic influences from sensory synapses during early development regulates the density and organization of motor inputs on mature Renshaw cells.
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Affiliation(s)
- Valerie C Siembab
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, 45435
| | - Laura Gomez-Perez
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, 30322
| | - Travis M Rotterman
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, 30322
| | - Neil A Shneider
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, New York, New York, 10032
| | - Francisco J Alvarez
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, 45435.,Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, 30322
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33
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Amaniti EM, Kelman A, Mason JO, Theil T. Cerebral Cortex Expression of Gli3 Is Required for Normal Development of the Lateral Olfactory Tract. PLoS One 2015; 10:e0141525. [PMID: 26509897 PMCID: PMC4624982 DOI: 10.1371/journal.pone.0141525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 10/09/2015] [Indexed: 02/03/2023] Open
Abstract
Formation of the lateral olfactory tract (LOT) and innervation of the piriform cortex represent fundamental steps to allow the transmission of olfactory information to the cerebral cortex. Several transcription factors, including the zinc finger transcription factor Gli3, influence LOT formation by controlling the development of mitral cells from which LOT axons emanate and/or by specifying the environment through which these axons navigate. Gli3 null and hypomorphic mutants display severe defects throughout the territory covered by the developing lateral olfactory tract, making it difficult to identify specific roles for Gli3 in its development. Here, we used Emx1Cre;Gli3fl/fl conditional mutants to investigate LOT formation and colonization of the olfactory cortex in embryos in which loss of Gli3 function is restricted to the dorsal telencephalon. These mutants form an olfactory bulb like structure which does not protrude from the telencephalic surface. Nevertheless, mitral cells are formed and their axons enter the piriform cortex though the LOT is shifted medially. Mitral axons also innervate a larger target area consistent with an enlargement of the piriform cortex and form aberrant projections into the deeper layers of the piriform cortex. No obvious differences were found in the expression patterns of key guidance cues. However, we found that an expansion of the piriform cortex temporally coincides with the arrival of LOT axons, suggesting that Gli3 affects LOT positioning and target area innervation through controlling the development of the piriform cortex.
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Affiliation(s)
- Eleni-Maria Amaniti
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Alexandra Kelman
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - John O. Mason
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Thomas Theil
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
- * E-mail:
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34
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Russ JB, Kaltschmidt JA. From induction to conduction: how intrinsic transcriptional priming of extrinsic neuronal connectivity shapes neuronal identity. Open Biol 2015; 4:rsob.140144. [PMID: 25297387 PMCID: PMC4221895 DOI: 10.1098/rsob.140144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Every behaviour of an organism relies on an intricate and vastly diverse network of neurons whose identity and connectivity must be specified with extreme precision during development. Intrinsically, specification of neuronal identity depends heavily on the expression of powerful transcription factors that direct numerous features of neuronal identity, including especially properties of neuronal connectivity, such as dendritic morphology, axonal targeting or synaptic specificity, ultimately priming the neuron for incorporation into emerging circuitry. As the neuron's early connectivity is established, extrinsic signals from its pre- and postsynaptic partners feedback on the neuron to further refine its unique characteristics. As a result, disruption of one component of the circuitry during development can have vital consequences for the proper identity specification of its synaptic partners. Recent studies have begun to harness the power of various transcription factors that control neuronal cell fate, including those that specify a neuron's subtype-specific identity, seeking insight for future therapeutic strategies that aim to reconstitute damaged circuitry through neuronal reprogramming.
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Affiliation(s)
- Jeffrey B Russ
- Weill Cornell/Rockefeller University/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065, USA Neuroscience Program, Weill Cornell Medical College, New York, NY 10065, USA Developmental Biology Program, Sloan Kettering Institute, New York, NY 10065, USA
| | - Julia A Kaltschmidt
- Neuroscience Program, Weill Cornell Medical College, New York, NY 10065, USA Cell and Developmental Biology Program, Weill Cornell Medical College, New York, NY 10065, USA Developmental Biology Program, Sloan Kettering Institute, New York, NY 10065, USA
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35
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Lu DC, Niu T, Alaynick WA. Molecular and cellular development of spinal cord locomotor circuitry. Front Mol Neurosci 2015; 8:25. [PMID: 26136656 PMCID: PMC4468382 DOI: 10.3389/fnmol.2015.00025] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/30/2015] [Indexed: 01/20/2023] Open
Abstract
The spinal cord of vertebrate animals is comprised of intrinsic circuits that are capable of sensing the environment and generating complex motor behaviors. There are two major perspectives for understanding the biology of this complicated structure. The first approaches the spinal cord from the point of view of function and is based on classic and ongoing research in electrophysiology, adult behavior, and spinal cord injury. The second view considers the spinal cord from a developmental perspective and is founded mostly on gene expression and gain-of-function and loss-of-function genetic experiments. Together these studies have uncovered functional classes of neurons and their lineage relationships. In this review, we summarize our knowledge of developmental classes, with an eye toward understanding the functional roles of each group.
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Affiliation(s)
- Daniel C Lu
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA USA
| | - Tianyi Niu
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA USA
| | - William A Alaynick
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA USA
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36
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Klausmeyer A, Stern D, Wiese S. Isolation and culture of spinal cord motor neurons. ACTA ACUST UNITED AC 2015; 66:1.9.1-1.9.10. [PMID: 25727328 DOI: 10.1002/0471143030.cb0109s66] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Isolated spinal motoneurons are a powerful tool for studying basic mechanisms of neurite growth and survival. Since motoneurons are a minor population of developing spinal cord cells, they need to be purified and enriched to separate them from non-neuronal cells. Therefore, the particular feature of embryonic motoneurons to express the low affinity neurotrophin receptor p75(NTR) is used to separate the motoneurons from other contaminating cells. Two ways are described to isolate embryonic motoneurons: the basic protocol taking advantage of the ability of p75(NTR) to bind lectin, and an alternative method using an antibody against p75(NTR) for a panning procedure. These protocols comprise suggestions for the cultivation of the isolated motoneurons for experiments regarding neural outgrowth and survival as well as instruction for the preparation of proteins of the cells.
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Affiliation(s)
- Alice Klausmeyer
- Institute for Cell Morphology and Molecular Neurobiology, Group for Cell Biology, Ruhr-University, Bochum, Germany
| | - D Stern
- Institute for Cell Morphology and Molecular Neurobiology, Group for Cell Biology, Ruhr-University, Bochum, Germany
| | - S Wiese
- Institute for Cell Morphology and Molecular Neurobiology, Group for Cell Biology, Ruhr-University, Bochum, Germany
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37
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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: 190] [Impact Index Per Article: 19.0] [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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38
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Kandemir B, Caglayan B, Hausott B, Erdogan B, Dag U, Demir O, Sogut MS, Klimaschewski L, Kurnaz IA. Pea3 transcription factor promotes neurite outgrowth. Front Mol Neurosci 2014; 7:59. [PMID: 25018694 PMCID: PMC4072091 DOI: 10.3389/fnmol.2014.00059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/08/2014] [Indexed: 01/13/2023] Open
Abstract
Pea3 subfamily of E–twenty six transcription factors consist of three major -exhibit branching morphogenesis, the function of Pea3 family in nervous system development and regeneration is only beginning to unfold. In this study, we provide evidence that Pea3 can directs neurite extension and axonal outgrowth in different model systems, and that Serine 90 is important for this function. We have also identified neurofilament-L and neurofilament-M as two putative novel targets for Pea3.
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Affiliation(s)
- Basak Kandemir
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey
| | - Berrak Caglayan
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey ; Division of Neuroanatomy, Innsbruck Medical University Innsbruck, Austria
| | - Barbara Hausott
- Division of Neuroanatomy, Innsbruck Medical University Innsbruck, Austria
| | - Burcu Erdogan
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey
| | - Ugur Dag
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey
| | - Ozlem Demir
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey
| | - Melis S Sogut
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey
| | - Lars Klimaschewski
- Division of Neuroanatomy, Innsbruck Medical University Innsbruck, Austria
| | - Isil A Kurnaz
- Molecular Neurobiology Laboratory, Department of Genetics and Bioengineering, Yeditepe University Istanbul, Turkey
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39
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Allodi I, Hedlund E. Directed midbrain and spinal cord neurogenesis from pluripotent stem cells to model development and disease in a dish. Front Neurosci 2014; 8:109. [PMID: 24904255 PMCID: PMC4033221 DOI: 10.3389/fnins.2014.00109] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 04/28/2014] [Indexed: 12/29/2022] Open
Abstract
Induction of specific neuronal fates is restricted in time and space in the developing CNS through integration of extrinsic morphogen signals and intrinsic determinants. Morphogens impose regional characteristics on neural progenitors and establish distinct progenitor domains. Such domains are defined by unique expression patterns of fate determining transcription factors. These processes of neuronal fate specification can be recapitulated in vitro using pluripotent stem cells. In this review, we focus on the generation of dopamine neurons and motor neurons, which are induced at ventral positions of the neural tube through Sonic hedgehog (Shh) signaling, and defined at anteroposterior positions by fibroblast growth factor (Fgf) 8, Wnt1, and retinoic acid (RA). In vitro utilization of these morphogenic signals typically results in the generation of multiple neuronal cell types, which are defined at the intersection of these signals. If the purpose of in vitro neurogenesis is to generate one cell type only, further lineage restriction can be accomplished by forced expression of specific transcription factors in a permissive environment. Alternatively, cell-sorting strategies allow for selection of neuronal progenitors or mature neurons. However, modeling development, disease and prospective therapies in a dish could benefit from structured heterogeneity, where desired neurons are appropriately synaptically connected and thus better reflect the three-dimensional structure of that region. By modulating the extrinsic environment to direct sequential generation of neural progenitors within a domain, followed by self-organization and synaptic establishment, a reductionist model of that brain region could be created. Here we review recent advances in neuronal fate induction in vitro, with a focus on the interplay between cell intrinsic and extrinsic factors, and discuss the implications for studying development and disease in a dish.
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Affiliation(s)
- Ilary Allodi
- Department of Neuroscience, Karolinska Institutet Stockholm, Sweden
| | - Eva Hedlund
- Department of Neuroscience, Karolinska Institutet Stockholm, Sweden
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Francius C, Clotman F. Generating spinal motor neuron diversity: a long quest for neuronal identity. Cell Mol Life Sci 2014; 71:813-29. [PMID: 23765105 PMCID: PMC11113339 DOI: 10.1007/s00018-013-1398-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/30/2013] [Accepted: 05/31/2013] [Indexed: 03/26/2023]
Abstract
Understanding how thousands of different neuronal types are generated in the CNS constitutes a major challenge for developmental neurobiologists and is a prerequisite before considering cell or gene therapies of nervous lesions or pathologies. During embryonic development, spinal motor neurons (MNs) segregate into distinct subpopulations that display specific characteristics and properties including molecular identity, migration pattern, allocation to specific motor columns, and innervation of defined target. Because of the facility to correlate these different characteristics, the diversification of spinal MNs has become the model of choice for studying the molecular and cellular mechanisms underlying the generation of multiple neuronal populations in the developing CNS. Therefore, how spinal motor neuron subpopulations are produced during development has been extensively studied during the last two decades. In this review article, we will provide a comprehensive overview of the genetic and molecular mechanisms that contribute to the diversification of spinal MNs.
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Affiliation(s)
- Cédric Francius
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, 55 Avenue Hippocrate, Box (B1.55.11), 1200 Brussels, Belgium
| | - Frédéric Clotman
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, 55 Avenue Hippocrate, Box (B1.55.11), 1200 Brussels, Belgium
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Kania A. Spinal motor neuron migration and the significance of topographic organization in the nervous system. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 800:133-48. [PMID: 24243104 DOI: 10.1007/978-94-007-7687-6_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The nervous system displays a high degree of topographic organisation such that neuronal soma position is closely correlated to axonal trajectory. One example of such order is the myotopic organisation of the motor system where spinal motor neuron position parallels that of target muscles. This chapter will discuss the molecular mechanisms underlying motor neuron soma positioning, which include transcriptional control of Reelin signaling and cadherin expression. As the same transcription factors have been shown to control motor axon innervation of target muscles, a simple mechanism of topographic organisation specification is becoming evident raising the question of how coordinating soma position with axon trajectory might be important for nervous system wiring and its function.
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Affiliation(s)
- Artur Kania
- Institut de recherches cliniques de Montréal (IRCM), 110, ave. des Pins Ouest, Montréal, QC, H2W 1R7, Canada,
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Neurotrophin signalling and transcription programmes interactions in the development of somatosensory neurons. Handb Exp Pharmacol 2014; 220:329-53. [PMID: 24668479 DOI: 10.1007/978-3-642-45106-5_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Somatosensory neurons of the dorsal root ganglia are generated from multipotent neural crest cells by a process of progressive specification and differentiation. Intrinsic transcription programmes active in somatosensory neuron progenitors and early post-mitotic neurons drive the cell-type expression of neurotrophin receptors. In turn, signalling by members of the neurotrophin family controls expression of transcription factors that regulate neuronal sub-type specification. This chapter explores the mechanisms by which this crosstalk between neurotrophin signalling and transcription programmes generates the diverse functional sub-types of somatosensory neurons found in the mature animal.
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A local source of FGF initiates development of the unmyelinated lineage of sensory neurons. J Neurosci 2013; 33:17656-66. [PMID: 24198358 DOI: 10.1523/jneurosci.1090-13.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The principle by which unmyelinated primary sensory neurons transducing thermal, itch and pain perception are specified in early development is unknown. These classes of sensory neurons diversify from a common population of late-born neurons, which initiate expression of Runt homology domain transcription factor RUNX1 and the nerve growth factor receptor TrkA. Here, we report that signals emanating from within the mouse dorsal root ganglion mediated partly by early-born neurons destined to a myelinated phenotype participate in fating late-born RUNX1(+)/TrkA(+) neurons. Inductive factors include FGFs via activation of FGF receptor 1 (FGFR1). Consistently, FGF2 is sufficient to induce expression of RUNX1, and Fgfr1 conditional mutant mice display deficits in fating of the common population of late-born RUNX1(+)/TrkA(+) neurons that develop into unmyelinated neurons. Thus, the distinct lineages of sensory neurons are acquired in response to increasing FGF levels provided by a rising number of born neurons.
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Pea3 transcription factor family members Etv4 and Etv5 mediate retrograde signaling and axonal growth of DRG sensory neurons in response to NGF. J Neurosci 2013; 33:15940-51. [PMID: 24089499 DOI: 10.1523/jneurosci.0928-13.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Nerve growth factor (NGF) is a target-derived neurotrophic growth factor that controls many aspects of sensory and sympathetic neuronal development. The identification of transcription factors and downstream target genes that mediate NGF-dependent neuronal differentiation and target field innervation is currently a major challenge. Here, we show that the Pea3 transcription factor family members Etv4 and Etv5 are expressed by developing TrkA-positive dorsal root ganglion (DRG) neurons during the period of target innervation. Real-time PCR assays indicated that Etv4 and Etv5 mRNAs are significantly induced by NGF in different neuronal cells, suggesting that they could be involved in the biological responses induced by this neurotrophin. Interestingly, distal axon application of NGF in compartmentalized cultures of rat DRG sensory neurons was sufficient to induce a significant increase in Etv4 and Etv5 mRNA expression. Pharmacological assays also revealed that activation of MEK/ERK (MAPK) pathway is required for Etv4 and Etv5 gene induction in response to NGF. Downregulation of Etv4 and Etv5 using small interference RNA knockdown experiments inhibited NGF-induced neurite outgrowth of rat sensory neurons, while overexpression of full-length Etv4 or Etv5 potentiated neuronal differentiation in response to this neurotrophin. Together, these data establish Etv4 and Etv5 as essential molecules of the transcriptional program linking neurotrophin signaling to sensory neuronal differentiation, and suggest that they can be involved in NGF-mediated target innervation.
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Optogenetic-mediated increases in in vivo spontaneous activity disrupt pool-specific but not dorsal-ventral motoneuron pathfinding. Proc Natl Acad Sci U S A 2013; 110:17528-33. [PMID: 24101487 DOI: 10.1073/pnas.1316457110] [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: 12/11/2022] Open
Abstract
Rhythmic waves of spontaneous electrical activity are widespread in the developing nervous systems of birds and mammals, and although many aspects of neural development are activity-dependent, it has been unclear if rhythmic waves are required for in vivo motor circuit development, including the proper targeting of motoneurons to muscles. We show here that electroporated channelrhodopsin-2 can be activated in ovo with light flashes to drive waves at precise intervals of approximately twice the control frequency in intact chicken embryos. Optical monitoring of associated axial movements ensured that the altered frequency was maintained. In embryos thus stimulated, motor axons correctly executed the binary dorsal-ventral pathfinding decision but failed to make the subsequent pool-specific decision to target to appropriate muscles. This observation, together with the previous demonstration that slowing the frequency by half perturbed dorsal-ventral but not pool-specific pathfinding, shows that modest changes in frequency differentially disrupt these two major pathfinding decisions. Thus, many drugs known to alter early rhythmic activity have the potential to impair normal motor circuit development, and given the conservation between mouse and avian spinal cords, our observations are likely relevant to mammals, where such studies would be difficult to carry out.
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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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Abstract
OBJECTIVES Some stages of limb development can now be described in terms of gene sequences and functions. This paper reports on the development of the brachial plexus (BP) in the chick. It also presents a short review on the principles of the peripheral nerve outgrowth. METHODS The early development of the brachial plexus of chicken embryos is mapped using immunohistochemistry. This is then analysed in relation to the expression pattern of an axonal guidance gene, Semaphorin3a, by in situ hybridization studies. RESULTS The motor axons that innervate the chick wing emerge from the spinal cord in spinal nerves 12-17. These axons grow towards the developing limb and then congregate at its base to form the plexus. In response to unknown cues, these axons rearrange, before emerging in the defined nerve trunks that innervate the limb. The developmental stages of BP morphogenesis described here closely correlate with previous reports with a significant difference of a shorter 'waiting period'. DISCUSSION The development of the brachial plexus is now better understood. The waiting period, with more modern techniques, is observed to be shorter than previously reported. The significance of this and the role of the guidance molecule, Semaphorin3a, in this process, are being investigated and the results may have important implications on the management of brachial plexus palsy and other peripheral nerve lesions.
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Affiliation(s)
- Tam Dieu
- Department of Embryology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.
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Johnston RJ. Lessons about terminal differentiation from the specification of color-detecting photoreceptors in the Drosophila retina. Ann N Y Acad Sci 2013; 1293:33-44. [PMID: 23782311 DOI: 10.1111/nyas.12178] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Metazoans require highly diverse collections of cell types to sense, interpret, and react to the environment. Developmental programs incorporate deterministic and stochastic strategies in different contexts or different combinations to establish this multitude of cell fates. Precise genetic dissection of the processes controlling terminal photoreceptor differentiation in the Drosophila retina has revealed complex regulatory mechanisms required to generate differences in gene expression and cell fate. In this review, I discuss how a gene regulatory network interprets stochastic and regional inputs to determine the specification of color-detecting photoreceptor subtypes in the Drosophila retina. These combinatorial gene regulatory mechanisms will likely be broadly applicable to nervous system development and cell fate specification in general.
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Affiliation(s)
- Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA.
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Wnt7A identifies embryonic γ-motor neurons and reveals early postnatal dependence of γ-motor neurons on a muscle spindle-derived signal. J Neurosci 2012; 32:8725-31. [PMID: 22723712 DOI: 10.1523/jneurosci.1160-12.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Motor pools comprise a heterogeneous population of motor neurons that innervate distinct intramuscular targets. While the organization of motor neurons into motor pools has been well described, the time course and mechanism of motor pool diversification into functionally distinct classes remains unclear. γ-Motor neurons (γ-MNs) and α-motor neurons (α-MNs) differ in size, molecular identity, synaptic input and peripheral target. While α-MNs innervate extrafusal skeletal muscle fibers to mediate muscle contraction, γ-MNs innervate intrafusal fibers of the muscle spindle, and regulate sensitivity of the muscle spindle in response to stretch. In this study, we find that the secreted signaling molecule Wnt7a is selectively expressed in γ-MNs in the mouse spinal cord by embryonic day 17.5 and continues to molecularly distinguish γ-from α-MNs into the third postnatal week. Our data demonstrate that Wnt7a is the earliest known γ-MN marker, supporting a model of developmental divergence between α- and γ-MNs at embryonic stages. Furthermore, using Wnt7a expression as an early marker of γ-MN identity, we demonstrate a previously unknown dependence of γ-MNs on a muscle spindle-derived, GDNF-independent signal during the first postnatal week.
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