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Lettieri A, Oleari R, van den Munkhof MH, van Battum EY, Verhagen MG, Tacconi C, Spreafico M, Paganoni AJJ, Azzarelli R, Andre' V, Amoruso F, Palazzolo L, Eberini I, Dunkel L, Howard SR, Fantin A, Pasterkamp RJ, Cariboni A. SEMA6A drives GnRH neuron-dependent puberty onset by tuning median eminence vascular permeability. Nat Commun 2023; 14:8097. [PMID: 38062045 PMCID: PMC10703890 DOI: 10.1038/s41467-023-43820-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Innervation of the hypothalamic median eminence by Gonadotropin-Releasing Hormone (GnRH) neurons is vital to ensure puberty onset and successful reproduction. However, the molecular and cellular mechanisms underlying median eminence development and pubertal timing are incompletely understood. Here we show that Semaphorin-6A is strongly expressed by median eminence-resident oligodendrocytes positioned adjacent to GnRH neuron projections and fenestrated capillaries, and that Semaphorin-6A is required for GnRH neuron innervation and puberty onset. In vitro and in vivo experiments reveal an unexpected function for Semaphorin-6A, via its receptor Plexin-A2, in the control of median eminence vascular permeability to maintain neuroendocrine homeostasis. To support the significance of these findings in humans, we identify patients with delayed puberty carrying a novel pathogenic variant of SEMA6A. In all, our data reveal a role for Semaphorin-6A in regulating GnRH neuron patterning by tuning the median eminence vascular barrier and thereby controlling puberty onset.
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Affiliation(s)
- Antonella Lettieri
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
- Department of Health Sciences, University of Milan, Via di Rudinì 8, 20142, Milano, Italy
| | - Roberto Oleari
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Marleen Hester van den Munkhof
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Eljo Yvette van Battum
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Marieke Geerte Verhagen
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
- VIB-KU Leuven, Center for Brain & Disease Research, Leuven, Belgium
| | - Carlotta Tacconi
- Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy
- Division of Immunology, Transplantation, and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Marco Spreafico
- Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy
| | | | - Roberta Azzarelli
- Wellcome - Medical Research Council Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, CB2 0AW, UK
| | - Valentina Andre'
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Federica Amoruso
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Luca Palazzolo
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Ivano Eberini
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Leo Dunkel
- Centre for Endocrinology William Harvey Research Institute Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Sasha Rose Howard
- Centre for Endocrinology William Harvey Research Institute Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
- Department of Paediatric Endocrinology, Barts Health NHS Trust, London, E1 1FR, UK
| | - Alessandro Fantin
- Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
| | - Ronald Jeroen Pasterkamp
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands.
| | - Anna Cariboni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy.
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James RE, Hamilton NR, Huffman LN, Pasterkamp J, Goff LA, Kolodkin AL. Semaphorin 6A in Retinal Ganglion Cells Regulates Functional Specialization of the Inner Retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.18.567662. [PMID: 38014224 PMCID: PMC10680864 DOI: 10.1101/2023.11.18.567662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
To form functional circuits, neurons must settle in their appropriate cellular locations and then project and elaborate neurites to contact their target synaptic neuropils. Laminar organization within the vertebrate retinal inner plexiform layer (IPL) facilitates pre- and postsynaptic neurite targeting, yet, the precise mechanisms underlying establishment of functional IPL subdomains are not well understood. Here we explore mechanisms defining the compartmentalization of OFF and ON neurites generally, and OFF and ON direction-selective neurites specifically, within the developing IPL. We show that semaphorin 6A (Sema6A), a repulsive axon guidance cue, is required for delineation of OFF versus ON circuits within the IPL: in the Sema6a null IPL, the boundary between OFF and ON domains is blurred. Furthermore, Sema6A expressed by retinal ganglion cells (RGCs) directs laminar segregation of OFF and ON starburst amacrine cell (SAC) dendritic scaffolds, which themselves serve as a substrate upon which other retinal neurites elaborate. These results demonstrate for the first time that RGCs, the first neuron-type born within the retina, play an active role in functional specialization of the IPL. Retinal ganglion cell-dependent regulation of OFF and ON starburst amacrine cell dendritic scaffold segregation prevents blurring of OFF versus ON functional domains in the murine inner plexiform layer.
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Liaci C, Camera M, Zamboni V, Sarò G, Ammoni A, Parmigiani E, Ponzoni L, Hidisoglu E, Chiantia G, Marcantoni A, Giustetto M, Tomagra G, Carabelli V, Torelli F, Sala M, Yanagawa Y, Obata K, Hirsch E, Merlo GR. Loss of ARHGAP15 affects the directional control of migrating interneurons in the embryonic cortex and increases susceptibility to epilepsy. Front Cell Dev Biol 2022; 10:875468. [PMID: 36568982 PMCID: PMC9774038 DOI: 10.3389/fcell.2022.875468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 11/07/2022] [Indexed: 12/13/2022] Open
Abstract
GTPases of the Rho family are components of signaling pathways linking extracellular signals to the control of cytoskeleton dynamics. Among these, RAC1 plays key roles during brain development, ranging from neuronal migration to neuritogenesis, synaptogenesis, and plasticity. RAC1 activity is positively and negatively controlled by guanine nucleotide exchange factors (GEFs), guanosine nucleotide dissociation inhibitors (GDIs), and GTPase-activating proteins (GAPs), but the specific role of each regulator in vivo is poorly known. ARHGAP15 is a RAC1-specific GAP expressed during development in a fraction of migrating cortical interneurons (CINs) and in the majority of adult CINs. During development, loss of ARHGAP15 causes altered directionality of the leading process of tangentially migrating CINs, along with altered morphology in vitro. Likewise, time-lapse imaging of embryonic CINs revealed a poorly coordinated directional control during radial migration, possibly due to a hyper-exploratory behavior. In the adult cortex, the observed defects lead to subtle alteration in the distribution of CALB2-, SST-, and VIP-positive interneurons. Adult Arhgap15-knock-out mice also show reduced CINs intrinsic excitability, spontaneous subclinical seizures, and increased susceptibility to the pro-epileptic drug pilocarpine. These results indicate that ARHGAP15 imposes a fine negative regulation on RAC1 that is required for morphological maturation and directional control during CIN migration, with consequences on their laminar distribution and inhibitory function.
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Affiliation(s)
- Carla Liaci
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Mattia Camera
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Valentina Zamboni
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Gabriella Sarò
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Alessandra Ammoni
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | | | - Luisa Ponzoni
- Neuroscience Institute, Consiglio Nazionale Ricerche, Milan, Italy
| | - Enis Hidisoglu
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | - Giuseppe Chiantia
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | - Maurizio Giustetto
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Giulia Tomagra
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | | | - Federico Torelli
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany,Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Mariaelvina Sala
- Neuroscience Institute, Consiglio Nazionale Ricerche, Milan, Italy
| | - Yuchio Yanagawa
- Department of Genetic Behavioral Neuroscience, Gunma University, Maebashi, Japan
| | | | - Emilio Hirsch
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Giorgio R. Merlo
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy,*Correspondence: Giorgio R. Merlo,
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Moreno-Bravo JA, Rappeneau Q, Roig-Puiggros S, Sotelo C, Chédotal A. Uncoupling axon guidance and neuronal migration in Robo3-deficient inferior olivary neurons. J Comp Neurol 2022; 530:2868-2880. [PMID: 35811330 DOI: 10.1002/cne.25381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/25/2022] [Accepted: 06/02/2022] [Indexed: 12/18/2022]
Abstract
Inferior olivary (IO) neurons are born in the dorsal hindbrain and migrate tangentially toward the ventral midline. During their dorsoventral migration, IO neurons extend long leading processes that cross the midline, transform into axons, and project into the contralateral cerebellum. In absence of the axon guidance receptor Robo3, IO axons fail to cross the midline and project to the ipsilateral cerebellum. Remarkably, the IO cell bodies still reach the midline where they form a nucleus of abnormal cytoarchitecture. The mechanisms underlying the migration of Robo3-deficient IO neurons are unknown. Here, we used three-dimensional imaging and transgenic mice to label subsets of IO neurons and study their migratory behavior in Robo3 knockout. We show that IO migration is delayed in absence of Robo3. Strikingly, Robo3-deficient IO neurons progress toward the midline in a direction opposite to their axons. This occurs through a change of polarity and the generation of a second leading process at the rear of the cell. These results suggest that Robo3 receptor controls the establishment of neuronal polarity and the coupling of axonogenesis and cell body migration in IO neurons.
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Affiliation(s)
- Juan Antonio Moreno-Bravo
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France.,Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), San Juan de Alicante, Spain
| | - Quentin Rappeneau
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | | | | | - Alain Chédotal
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
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5
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Van Battum E, Heitz-Marchaland C, Zagar Y, Fouquet S, Kuner R, Chédotal A. Plexin-B2 controls the timing of differentiation and the motility of cerebellar granule neurons. eLife 2021; 10:60554. [PMID: 34100719 PMCID: PMC8211449 DOI: 10.7554/elife.60554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
Plexin-B2 deletion leads to aberrant lamination of cerebellar granule neurons (CGNs) and Purkinje cells. Although in the cerebellum Plexin-B2 is only expressed by proliferating CGN precursors in the outer external granule layer (oEGL), its function in CGN development is still elusive. Here, we used 3D imaging, in vivo electroporation and live-imaging techniques to study CGN development in novel cerebellum-specific Plxnb2 conditional knockout mice. We show that proliferating CGNs in Plxnb2 mutants not only escape the oEGL and mix with newborn postmitotic CGNs. Furthermore, motility of mitotic precursors and early postmitotic CGNs is altered. Together, this leads to the formation of ectopic patches of CGNs at the cerebellar surface and an intermingling of normally time-stamped parallel fibers in the molecular layer (ML), and aberrant arborization of Purkinje cell dendrites. There results suggest that Plexin-B2 restricts CGN motility and might have a function in cytokinesis.
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Affiliation(s)
- Eljo Van Battum
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Yvrick Zagar
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Stéphane Fouquet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Rohini Kuner
- Pharmacology Institute, Heidelberg University, Heidelberg, Germany
| | - Alain Chédotal
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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6
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Cadilhac C, Bachy I, Forget A, Hodson DJ, Jahannault-Talignani C, Furley AJ, Ayrault O, Mollard P, Sotelo C, Ango F. Excitatory granule neuron precursors orchestrate laminar localization and differentiation of cerebellar inhibitory interneuron subtypes. Cell Rep 2021; 34:108904. [PMID: 33789110 DOI: 10.1016/j.celrep.2021.108904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 12/19/2020] [Accepted: 03/03/2021] [Indexed: 12/18/2022] Open
Abstract
GABAergic interneurons migrate long distances through stereotyped migration programs toward specific laminar positions. During their migration, GABAergic interneurons are morphologically alike but then differentiate into a rich array of interneuron subtypes critical for brain function. How interneuron subtypes acquire their final phenotypic traits remains largely unknown. Here, we show that cerebellar molecular layer GABAergic interneurons, derived from the same progenitor pool, use separate migration paths to reach their laminar position and differentiate into distinct basket cell (BC) and stellate cell (SC) GABAergic interneuron subtypes. Using two-photon live imaging, we find that SC final laminar position requires an extra step of tangential migration supported by a subpopulation of glutamatergic granule cells (GCs). Conditional depletion of GCs affects SC differentiation but does not affect BCs. Our results reveal how timely feedforward control of inhibitory interneuron migration path regulates their terminal differentiation and, thus, establishment of the local inhibitory circuit assembly.
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Affiliation(s)
| | - Isabelle Bachy
- IGF, University Montpellier, CNRS, INSERM, Montpellier, France
| | - Antoine Forget
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signaling Radiobiology and Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signaling Radiobiology and Cancer, 91400 Orsay, France
| | - David J Hodson
- Institute of Metabolism and Systems Research and Centre of Membrane Proteins and Receptors, University of Birmingham, Edgbaston B15 2TT, UK
| | | | - Andrew J Furley
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Olivier Ayrault
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signaling Radiobiology and Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signaling Radiobiology and Cancer, 91400 Orsay, France
| | - Patrice Mollard
- IGF, University Montpellier, CNRS, INSERM, Montpellier, France
| | | | - Fabrice Ango
- IGF, University Montpellier, CNRS, INSERM, Montpellier, France; INM, University Montpellier, INSERM, CNRS, Montpellier, France.
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7
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Consalez GG, Goldowitz D, Casoni F, Hawkes R. Origins, Development, and Compartmentation of the Granule Cells of the Cerebellum. Front Neural Circuits 2021; 14:611841. [PMID: 33519389 PMCID: PMC7843939 DOI: 10.3389/fncir.2020.611841] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/17/2020] [Indexed: 12/21/2022] Open
Abstract
Granule cells (GCs) are the most numerous cell type in the cerebellum and indeed, in the brain: at least 99% of all cerebellar neurons are granule cells. In this review article, we first consider the formation of the upper rhombic lip, from which all granule cell precursors arise, and the way by which the upper rhombic lip generates the external granular layer, a secondary germinal epithelium that serves to amplify the upper rhombic lip precursors. Next, we review the mechanisms by which postmitotic granule cells are generated in the external granular layer and migrate radially to settle in the granular layer. In addition, we review the evidence that far from being a homogeneous population, granule cells come in multiple phenotypes with distinct topographical distributions and consider ways in which the heterogeneity of granule cells might arise during development.
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Affiliation(s)
- G Giacomo Consalez
- Division of Neuroscience, San Raffaele Scientific Institute, San Raffaele University, Milan, Italy
| | - Daniel Goldowitz
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Filippo Casoni
- Division of Neuroscience, San Raffaele Scientific Institute, San Raffaele University, Milan, Italy
| | - Richard Hawkes
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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8
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Iskusnykh IY, Fattakhov N, Buddington RK, Chizhikov VV. Intrauterine growth restriction compromises cerebellar development by affecting radial migration of granule cells via the JamC/Pard3a molecular pathway. Exp Neurol 2020; 336:113537. [PMID: 33259808 DOI: 10.1016/j.expneurol.2020.113537] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/30/2020] [Accepted: 11/22/2020] [Indexed: 12/30/2022]
Abstract
Intrauterine growth restriction (IUGR) affects ~10% of human pregnancies, results in infants born small for gestational age (SGA), and is associated with motor and cognitive deficits. Human studies suggest that some deficits in SGA patients originate in the cerebellum, a major motor-coordination and cognitive center, but the underlying mechanisms remain unknown. To identify the cerebellar developmental program affected by IUGR, we analyzed the pig as a translational animal model in which some fetuses spontaneously develop IUGR due to early-onset chronic placental insufficiency. Similar to humans, SGA pigs revealed small cerebella, which contained fewer mature granule cells (GCs) in the internal granule cell layer (IGL). Surprisingly, newborn SGA pigs had increased proliferation of GC precursors in the external granule cell layer (EGL), which was associated with an increased density of Purkinje cells, known to non-autonomously promote the proliferation of GCs. However, the GCs of SGA pigs did not properly initiate exit from the EGL to IGL, which was associated with a decreased density of guiding Bergmann glial fibers, reduced expression of pro-migratory genes Pard3a, JamC and Sema6a, and increased apoptosis. While proliferation spontaneously normalized during postnatal development, accumulation of pre-migratory GCs and apoptosis in the EGL were long-lasting consequences of IUGR. Using organotypic cerebellar slice cultures, we showed that normalizing expression of Pard3a and JamC, which operate in the same molecular pathway in GCs, was sufficient to rescue both migratory and, at a later time point, apoptotic defects of IUGR. Thus, a decreased exit of GCs from the EGL, due to disrupted Pard3a/JamC radial migration initiation pathway, is a major mechanism of IUGR-related cerebellar pathology.
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Affiliation(s)
- Igor Y Iskusnykh
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Nikolai Fattakhov
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Randal K Buddington
- Babies Taking Flight, Memphis, TN 38117, USA; School of Health Studies, University of Memphis, Memphis, TN 38152, USA; College of Nursing, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Victor V Chizhikov
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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9
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Schilling K. Moving into shape: cell migration during the development and histogenesis of the cerebellum. Histochem Cell Biol 2018; 150:13-36. [DOI: 10.1007/s00418-018-1677-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2018] [Indexed: 12/31/2022]
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10
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Neuronal expression patterns of the PlexinA family during zebrafish development. Gene Expr Patterns 2017; 27:56-66. [PMID: 29107805 DOI: 10.1016/j.gep.2017.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 12/15/2022]
Abstract
Plexins (Plxns) and Semaphorins (Semas) are key signaling molecules that regulate many aspects of development. Plxns are a family of transmembrane protein receptors that are activated upon extracellular binding by Semas. Activated Plxns trigger intracellular signaling cascades, which regulate a range of developmental processes, including axon guidance, neuronal positioning and vasculogenesis. Semas are a large family of both transmembrane and secreted signaling molecules, and show subtype specific binding to different Plxn family members. Each Plxn can play different roles in development, and so tightly regulated temporal and spatial expression of receptor subtypes is critical to ensure appropriate signaling. Here we elucidate the expression profiles of the plxnA family, plxnA1a, A1b, A2, A3 and A4 at 18, 24, 36, 48, 60 and 72 h post fertilization in the developing zebrafish. We show that PlxnA family members are expressed in neuronal tissues during zebrafish development, but exhibit key differences in expression within these tissues. We also highlight that plxnA1 has two genes in zebrafish, A1a and A1b, which show divergences in expression patterns during early development.
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11
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Doussau F, Dupont JL, Neel D, Schneider A, Poulain B, Bossu JL. Organotypic cultures of cerebellar slices as a model to investigate demyelinating disorders. Expert Opin Drug Discov 2017; 12:1011-1022. [PMID: 28712329 DOI: 10.1080/17460441.2017.1356285] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Demyelinating disorders, characterized by a chronic or episodic destruction of the myelin sheath, are a leading cause of neurological disability in young adults in western countries. Studying the complex mechanisms involved in axon myelination, demyelination and remyelination requires an experimental model preserving the neuronal networks and neuro-glial interactions. Organotypic cerebellar slice cultures appear to be the best alternative to in vivo experiments and the most commonly used model for investigating etiology or novel therapeutic strategies in multiple sclerosis. Areas covered: This review gives an overview of slice culture techniques and focuses on the use of organotypic cerebellar slice cultures on semi-permeable membranes for studying many aspects of axon myelination and cerebellar functions. Expert opinion: Cerebellar slice cultures are probably the easiest way to faithfully reproduce all stages of axon myelination/demyelination/remyelination in a three-dimensional neuronal network. However, in the cerebellum, neurological disability in multiple sclerosis also results from channelopathies which induce changes in Purkinje cell excitability. Cerebellar cultures offer easy access to electrophysiological approaches which are largely untapped and we believe that these cultures might be of great interest when studying changes in neuronal excitability, axonal conduction or synaptic properties that likely occur during multiple sclerosis.
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Affiliation(s)
- Frédéric Doussau
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Jean-Luc Dupont
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Dorine Neel
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Aline Schneider
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Bernard Poulain
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Jean Louis Bossu
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
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12
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Emerson SE, St Clair RM, Waldron AL, Bruno SR, Duong A, Driscoll HE, Ballif BA, McFarlane S, Ebert AM. Identification of target genes downstream of semaphorin6A/PlexinA2 signaling in zebrafish. Dev Dyn 2017; 246:539-549. [PMID: 28440030 DOI: 10.1002/dvdy.24512] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/10/2017] [Accepted: 04/08/2017] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Semaphorin (Sema)/Plexin (Plxn) signaling is important for many aspects of neuronal development, however, the transcriptional regulation imposed by this signaling pathway is unknown. Previously, we identified an essential role for Sema6A/PlxnA2 signaling in regulating proliferation and cohesion of retinal precursor cells (RPCs) during early eye development. This study used RNA isolated from control, Sema6A-deficient and PlxnA2-deficient zebrafish embryos in a microarray analysis to identify genes that were differentially expressed when this signaling pathway was disrupted. RESULTS We uncovered a set of 58 transcripts, and all but 1 were up-regulated in both sema6A and plxnA2 morphants. We validated gene expression changes in subset of candidates that are suggested to be involved in proliferation, migration or neuronal positioning. We further functionally evaluated one gene, rasl11b, as contributing to disrupted proliferation in sema6A and plxna2 morphants. Our results suggest rasl11b negatively regulates proliferation of RPCs in the developing zebrafish eye. CONCLUSIONS Microarray analysis has generated a resource of target genes downstream of Sema6A/PlxnA2 signaling, which can be further investigated to elucidate the downstream effects of this well-studied neuronal and vascular guidance signaling pathway. Developmental Dynamics 246:539-549, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Sarah E Emerson
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Riley M St Clair
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Ashley L Waldron
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Sierra R Bruno
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Anna Duong
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Heather E Driscoll
- Vermont Genetics Network Bioinformatics Core and Department of Biology, Norwich University, Northfield, Vermont
| | - Bryan A Ballif
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Sarah McFarlane
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Alicia M Ebert
- Department of Biology, University of Vermont, Burlington, Vermont
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Belle M, Parray A, Belle M, Chédotal A, Nguyen-Ba-Charvet KT. PlexinA2 and Sema6A are required for retinal progenitor cell migration. Dev Growth Differ 2016; 58:492-502. [PMID: 27301906 DOI: 10.1111/dgd.12298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/11/2016] [Accepted: 05/11/2016] [Indexed: 12/16/2022]
Abstract
In the vertebrate retina six types of neurons and one glial cell type are generated from multipotent retinal progenitor cells (RPCs) whose proliferation and differentiation are regulated by intrinsic and extrinsic factors. RPCs proliferate undergoing interkinetic nuclear migration within the neuroblastic layer, with their nuclei moving up and down along the apico-basal axis. Moreover, they only differentiate and therefore exit the cell cycle at the apical side of the neuroblastic layer. Sema6A and its receptors PlexinA4 and PlexinA2 control lamina stratification of the inner plexiform layer in the mouse retina. Nevertheless, their function in earlier developmental stages is still unknown. Here, we analyzed the embryonic retina of PlexinA2 and Sema6A knockout mice. Using time-lapse videomicroscopy we provide evidence that Sema6A/PlexinA2 signaling participates to interkinetic nuclear migration of RPCs around birth. When disrupted, RPCs migration is blocked at the apical side of the neuroblastic layer. This is the first evidence supporting a role for transmembrane molecules in the regulation of interkinetic nuclear migration in the mouse retina.
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Affiliation(s)
- Morgane Belle
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
| | - Aijaz Parray
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
| | - Martin Belle
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
| | - Alain Chédotal
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
| | - Kim Tuyen Nguyen-Ba-Charvet
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
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