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Cazares O, Chatterjee S, Lee P, Strietzel C, Bubolz JW, Harburg G, Howard J, Katzman S, Sanford J, Hinck L. Alveolar progenitor differentiation and lactation depends on paracrine inhibition of notch via ROBO1/CTNNB1/JAG1. Development 2021; 148:dev199940. [PMID: 34758082 PMCID: PMC8627605 DOI: 10.1242/dev.199940] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/23/2021] [Indexed: 11/09/2022]
Abstract
In the mammary gland, how alveolar progenitor cells are recruited to fuel tissue growth with each estrus cycle and pregnancy remains poorly understood. Here, we identify a regulatory pathway that controls alveolar progenitor differentiation and lactation by governing Notch activation in mouse. Loss of Robo1 in the mammary gland epithelium activates Notch signaling, which expands the alveolar progenitor cell population at the expense of alveolar differentiation, resulting in compromised lactation. ROBO1 is expressed in both luminal and basal cells, but loss of Robo1 in basal cells results in the luminal differentiation defect. In the basal compartment, ROBO1 inhibits the expression of Notch ligand Jag1 by regulating β-catenin (CTNNB1), which binds the Jag1 promoter. Together, our studies reveal how ROBO1/CTTNB1/JAG1 signaling in the basal compartment exerts paracrine control of Notch signaling in the luminal compartment to regulate alveolar differentiation during pregnancy.
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Affiliation(s)
- Oscar Cazares
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Sharmila Chatterjee
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Pinky Lee
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064, USA
| | | | - J. W. Bubolz
- Zoetis Inc. 333 Portage Street, Building 300, Kalamazoo, MI 49007, USA
| | - Gwyndolen Harburg
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Jon Howard
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
| | - Sol Katzman
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
| | - Jeremy Sanford
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Lindsay Hinck
- Institute for the Biology of Stem Cells, University of California, Santa Cruz, CA 95064, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
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2
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Terracciano R, Preianò M, Fregola A, Pelaia C, Montalcini T, Savino R. Mapping the SARS-CoV-2-Host Protein-Protein Interactome by Affinity Purification Mass Spectrometry and Proximity-Dependent Biotin Labeling: A Rational and Straightforward Route to Discover Host-Directed Anti-SARS-CoV-2 Therapeutics. Int J Mol Sci 2021; 22:E532. [PMID: 33430309 PMCID: PMC7825748 DOI: 10.3390/ijms22020532] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/02/2021] [Accepted: 01/04/2021] [Indexed: 12/12/2022] Open
Abstract
Protein-protein interactions (PPIs) are the vital engine of cellular machinery. After virus entry in host cells the global organization of the viral life cycle is strongly regulated by the formation of virus-host protein interactions. With the advent of high-throughput -omics platforms, the mirage to obtain a "high resolution" view of virus-host interactions has come true. In fact, the rapidly expanding approaches of mass spectrometry (MS)-based proteomics in the study of PPIs provide efficient tools to identify a significant number of potential drug targets. Generation of PPIs maps by affinity purification-MS and by the more recent proximity labeling-MS may help to uncover cellular processes hijacked and/or altered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), providing promising therapeutic targets. The possibility to further validate putative key targets from high-confidence interactions between viral bait and host protein through follow-up MS-based multi-omics experiments offers an unprecedented opportunity in the drug discovery pipeline. In particular, drug repurposing, making use of already existing approved drugs directly targeting these identified and validated host interactors, might shorten the time and reduce the costs in comparison to the traditional drug discovery process. This route might be promising for finding effective antiviral therapeutic options providing a turning point in the fight against the coronavirus disease-2019 (COVID-19) outbreak.
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Affiliation(s)
- Rosa Terracciano
- Department of Experimental and Clinical Medicine, University “Magna Græcia”, 88100 Catanzaro, Italy;
| | - Mariaimmacolata Preianò
- Department of Health Sciences, University “Magna Græcia”, 88100 Catanzaro, Italy; (M.P.); (A.F.)
| | - Annalisa Fregola
- Department of Health Sciences, University “Magna Græcia”, 88100 Catanzaro, Italy; (M.P.); (A.F.)
| | - Corrado Pelaia
- Respiratory Medicine Unit, University “Magna Græcia”, 88100 Catanzaro, Italy;
| | - Tiziana Montalcini
- Department of Experimental and Clinical Medicine, University “Magna Græcia”, 88100 Catanzaro, Italy;
| | - Rocco Savino
- Department of Medical and Surgical Sciences, University “Magna Græcia”, 88100 Catanzaro, Italy
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3
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Gonda Y, Namba T, Hanashima C. Beyond Axon Guidance: Roles of Slit-Robo Signaling in Neocortical Formation. Front Cell Dev Biol 2020; 8:607415. [PMID: 33425915 PMCID: PMC7785817 DOI: 10.3389/fcell.2020.607415] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/07/2020] [Indexed: 12/11/2022] Open
Abstract
The formation of the neocortex relies on intracellular and extracellular signaling molecules that are involved in the sequential steps of corticogenesis, ranging from the proliferation and differentiation of neural progenitor cells to the migration and dendrite formation of neocortical neurons. Abnormalities in these steps lead to disruption of the cortical structure and circuit, and underly various neurodevelopmental diseases, including dyslexia and autism spectrum disorder (ASD). In this review, we focus on the axon guidance signaling Slit-Robo, and address the multifaceted roles of Slit-Robo signaling in neocortical development. Recent studies have clarified the roles of Slit-Robo signaling not only in axon guidance but also in progenitor cell proliferation and migration, and the maturation of neocortical neurons. We further discuss the etiology of neurodevelopmental diseases, which are caused by defects in Slit-Robo signaling during neocortical formation.
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Affiliation(s)
- Yuko Gonda
- Department of Histology and Neuroanatomy, Tokyo Medical University, Tokyo, Japan
| | - Takashi Namba
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Neuroscience Center, HiLIFE – Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Carina Hanashima
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, Japan
- Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
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4
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Zhu Z, Han X, Li Y, Han C, Deng M, Zhang Y, Shen Q, Cao Y, Li Z, Wang X, Gu J, Liu X, Yang Y, Zhang Q, Hu F. Identification of ROBO1/2 and SCEL as candidate genes in Kallmann syndrome with emerging bioinformatic analysis. Endocrine 2020; 67:224-232. [PMID: 31325086 DOI: 10.1007/s12020-019-02010-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 07/09/2019] [Indexed: 12/30/2022]
Abstract
Kallmann syndrome (KS) is a congenital hypogonadotropic hypogonadism that coincides with anosmia or hyposmia. Although this rare genetic disease has a very low incidence, it harbors a complicated genetic heterogeneity, which indicates X-linked, autosomal, and oligogenic inheritance of puberty, sexuality, reproductivity, and olfactory defects. There has been limited elucidation of molecular etiologies completed to date. Here, a chromosome reciprocal translocation (46, XX, t (3; 13) (p13; q22)) was identified in a 27-year-old Chinese female diagnosed with KS. Genome sequencing found an intronic breakpoint of SCEL in chromosome 13 and an intergenic breakpoint between ROBO1 and ROBO2 in chromosome 3. This translocation resulted in the reduced expression levels of these genes. An array-CGH test captured no abnormal genomic copy numbers of clinical significance. The basic features of all known KS-related genes were also reviewed and analyzed for their roles in KS onset with bioinformatic methods. Signal pathway and gene enrichment analysis of KS-related genes suggested that these genes have integrated functions in neuronal migration and differentiation. An interesting chromosome locational pattern of KS-related genes was also discovered. This study provided constructive clues for further investigations into the molecular etiology of KS.
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Affiliation(s)
- Zuobin Zhu
- Department of Genetics, Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, China
| | - Xiaoxiao Han
- Center of Reproductive Medicine, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ying Li
- Medical Technology College, Xuzhou Medical University, Xuzhou, China
| | - Conghui Han
- Department of Urology, Xuzhou Central Hospital, Xuzhou, China
| | - Mengqiong Deng
- Clinical College of Xuzhou Medical University, Xuzhou, China
| | - Yuhao Zhang
- School of Anesthesiology of Xuzhou Medical University, Xuzhou, China
| | - Qing Shen
- Clinical College of Xuzhou Medical University, Xuzhou, China
| | - Yijuan Cao
- Clinical College of Xuzhou Medical University, Xuzhou, China
- Center of Reproductive Medicine, Xuzhou Central Hospital, Xuzhou, China
| | - Zhenbei Li
- Clinical College of Xuzhou Medical University, Xuzhou, China
- Center of Reproductive Medicine, Xuzhou Central Hospital, Xuzhou, China
| | - Xitao Wang
- Department of Urology, Xuzhou Central Hospital, Xuzhou, China
| | - Juan Gu
- Clinical College of Xuzhou Medical University, Xuzhou, China
- Center of Reproductive Medicine, Xuzhou Central Hospital, Xuzhou, China
| | - Xiaoyan Liu
- Clinical College of Xuzhou Medical University, Xuzhou, China
- Center of Reproductive Medicine, Xuzhou Central Hospital, Xuzhou, China
| | - Yaru Yang
- Clinical College of Xuzhou Medical University, Xuzhou, China
- Center of Reproductive Medicine, Xuzhou Central Hospital, Xuzhou, China
| | - Qiang Zhang
- Department of Genetics, Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, China.
| | - Fangfang Hu
- Clinical College of Xuzhou Medical University, Xuzhou, China.
- Center of Reproductive Medicine, Xuzhou Central Hospital, Xuzhou, China.
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5
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Gruner HN, Kim M, Mastick GS. Robo1 and 2 Repellent Receptors Cooperate to Guide Facial Neuron Cell Migration and Axon Projections in the Embryonic Mouse Hindbrain. Neuroscience 2019; 402:116-129. [PMID: 30685539 PMCID: PMC6435285 DOI: 10.1016/j.neuroscience.2019.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 01/12/2019] [Accepted: 01/14/2019] [Indexed: 11/19/2022]
Abstract
The facial nerve is necessary for our ability to eat, speak, and make facial expressions. Both the axons and cell bodies of the facial nerve undergo a complex embryonic developmental pattern involving migration of the cell bodies caudally and tangentially through rhombomeres, and simultaneously the axons projecting to exit the hindbrain to form the facial nerve. Our goal in this study was to test the functions of the chemorepulsive receptors Robo1 and Robo2 in facial neuron migration and axon projection by analyzing genetically marked motor neurons in double-mutant mouse embryos through the migration time course, E10.0-E13.5. In Robo1/2 double mutants, axon projection and cell body migration errors were more severe than in single mutants. Most axons did not make it to their motor exit point, and instead projected into and longitudinally within the floor plate. Surprisingly, some facial neurons had multiple axons exiting and projecting into the floor plate. At the same time, a subset of mutant facial cell bodies failed to migrate caudally, and instead either streamed dorsally toward the exit point or shifted into the floor plate. We conclude that Robo1 and Robo2 have redundant functions to guide multiple aspects of the complex cell migration of the facial nucleus, as well as regulating axon trajectories and suppressing formation of ectopic axons.
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Affiliation(s)
- Hannah N. Gruner
- Department of Biology, University of Nevada, 1664 N Virginia St, Reno, NV 89557, USA.
| | - Minkyung Kim
- Department of Biology, University of Nevada, 1664 N Virginia St, Reno, NV 89557, USA.
| | - Grant S. Mastick
- Department of Biology, University of Nevada, 1664 N Virginia St, Reno, NV 89557, USA.
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6
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Lindenmaier LB, Parmentier N, Guo C, Tissir F, Wright KM. Dystroglycan is a scaffold for extracellular axon guidance decisions. eLife 2019; 8:42143. [PMID: 30758284 PMCID: PMC6395066 DOI: 10.7554/elife.42143] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/13/2019] [Indexed: 12/13/2022] Open
Abstract
Axon guidance requires interactions between extracellular signaling molecules and transmembrane receptors, but how appropriate context-dependent decisions are coordinated outside the cell remains unclear. Here we show that the transmembrane glycoprotein Dystroglycan interacts with a changing set of environmental cues that regulate the trajectories of extending axons throughout the mammalian brain and spinal cord. Dystroglycan operates primarily as an extracellular scaffold during axon guidance, as it functions non-cell autonomously and does not require signaling through its intracellular domain. We identify the transmembrane receptor Celsr3/Adgrc3 as a binding partner for Dystroglycan, and show that this interaction is critical for specific axon guidance events in vivo. These findings establish Dystroglycan as a multifunctional scaffold that coordinates extracellular matrix proteins, secreted cues, and transmembrane receptors to regulate axon guidance.
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Affiliation(s)
| | - Nicolas Parmentier
- Institiute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Caiying Guo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Fadel Tissir
- Institiute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Kevin M Wright
- Vollum Institute, Oregon Health & Science University, Portland, United States
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7
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Backer S, Lokmane L, Landragin C, Deck M, Garel S, Bloch-Gallego E. Trio GEF mediates RhoA activation downstream of Slit2 and coordinates telencephalic wiring. Development 2018; 145:dev.153692. [PMID: 30177526 DOI: 10.1242/dev.153692] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/24/2018] [Indexed: 01/01/2023]
Abstract
Trio, a member of the Dbl family of guanine nucleotide exchange factors, activates Rac1 downstream of netrin 1/DCC signalling in axon outgrowth and guidance. Although it has been proposed that Trio also activates RhoA, the putative upstream factors remain unknown. Here, we show that Slit2 induces Trio-dependent RhoA activation, revealing a crosstalk between Slit and Trio/RhoA signalling. Consistently, we found that RhoA activity is hindered in vivo in T rio mutant mouse embryos. We next studied the development of the ventral telencephalon and thalamocortical axons, which have been previously shown to be controlled by Slit2. Remarkably, this analysis revealed that Trio knockout (KO) mice show phenotypes that bear strong similarities to the ones that have been reported in Slit2 KO mice in both guidepost corridor cells and thalamocortical axon pathfinding in the ventral telencephalon. Taken together, our results show that Trio induces RhoA activation downstream of Slit2, and support a functional role in ensuring the proper positioning of both guidepost cells and a major axonal tract. Our study indicates a novel role for Trio in Slit2 signalling and forebrain wiring, highlighting its role in multiple guidance pathways as well as in biological functions of importance for a factor involved in human brain disorders.
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Affiliation(s)
- Stéphanie Backer
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, 75014 Paris, France.,INSERM, U1016, Department of Development, Reproduction and Cancer, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Ludmilla Lokmane
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS UMR8197, INSERM U1024, PSL research University, 75005 Paris, France
| | - Camille Landragin
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, 75014 Paris, France.,INSERM, U1016, Department of Development, Reproduction and Cancer, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Marie Deck
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS UMR8197, INSERM U1024, PSL research University, 75005 Paris, France
| | - Sonia Garel
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS UMR8197, INSERM U1024, PSL research University, 75005 Paris, France
| | - Evelyne Bloch-Gallego
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, 75014 Paris, France .,INSERM, U1016, Department of Development, Reproduction and Cancer, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
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8
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Dominici C, Rappeneau Q, Zelina P, Fouquet S, Chédotal A. Non-cell autonomous control of precerebellar neuron migration by Slit and Robo proteins. Development 2018; 145:dev150375. [PMID: 29343636 DOI: 10.1242/dev.150375] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 12/11/2017] [Indexed: 02/05/2023]
Abstract
During development, precerebellar neurons migrate tangentially from the dorsal hindbrain to the floor plate. Their axons cross it but their cell bodies stop their ventral migration upon reaching the midline. It has previously been shown that Slit chemorepellents and their receptors, Robo1 and Robo2, might control the migration of precerebellar neurons in a repulsive manner. Here, we have used a conditional knockout strategy in mice to test this hypothesis. We show that the targeted inactivation of the expression of Robo1 and Robo2 receptors in precerebellar neurons does not perturb their migration and that they still stop at the midline. The selective ablation of the expression of all three Slit proteins in floor-plate cells has no effect on pontine neurons and only induces the migration of a small subset of inferior olivary neurons across the floor plate. Likewise, we show that the expression of Slit proteins in the facial nucleus is dispensable for pontine neuron migration. Together, these results show that Robo1 and Robo2 receptors act non-cell autonomously in migrating precerebellar neurons and that floor-plate signals, other than Slit proteins, must exist to prevent midline crossing.
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Affiliation(s)
- Chloé Dominici
- Sorbonne Universités, UPMC Paris 06, INSERM, CNRS, Institut de la Vision 75012, Paris, France
| | - Quentin Rappeneau
- Sorbonne Universités, UPMC Paris 06, INSERM, CNRS, Institut de la Vision 75012, Paris, France
| | - Pavol Zelina
- Sorbonne Universités, UPMC Paris 06, INSERM, CNRS, Institut de la Vision 75012, Paris, France
| | - Stéphane Fouquet
- Sorbonne Universités, UPMC Paris 06, INSERM, CNRS, Institut de la Vision 75012, Paris, France
| | - Alain Chédotal
- Sorbonne Universités, UPMC Paris 06, INSERM, CNRS, Institut de la Vision 75012, Paris, France
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9
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Ke C, Gao F, Tian X, Li C, Shi D, He W, Tian Y. Slit2/Robo1 Mediation of Synaptic Plasticity Contributes to Bone Cancer Pain. Mol Neurobiol 2017; 54:295-307. [PMID: 26738857 DOI: 10.1007/s12035-015-9564-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/29/2015] [Indexed: 12/11/2022]
Abstract
Synaptic plasticity is fundamental to spinal sensitivity of bone cancer pain. Here, we have shown that excitatory synaptogenesis contributes to bone cancer pain. New synapse formation requires neurite outgrowth and an interaction between axons and dendrites, accompanied by the appositional organization of presynaptic and postsynaptic specializations. We have shown that Slit2, Robo1, and RhoA act as such cues that promote neurite outgrowth and guide the axon for synapse formation. Sarcoma inoculation induces excitatory synaptogenesis and bone cancer pain which are reversed by Slit2 knockdown but aggravated by Robo1 knockdown. Synaptogenesis of cultured neurons are inhibited by Slit2 knockdown but enhanced by Robo1 knockdown. Sarcoma implantation induces an increase in Slit2 and decreases Robo1 and RhoA, while Slit2 knockdown results in an increase of Robo1 and RhoA. These results have demonstrated a molecular mechanism of synaptogenesis in bone cancer pain.
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Affiliation(s)
- Changbin Ke
- Institute of Anesthesiology and Pain (IAP) and Department of Anesthesiology, Taihe Hospital, Hubei University of Medicine, Shiyan City, 442000, Hubei Province, China
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Feng Gao
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xuebi Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Caijuan Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dai Shi
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wensheng He
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yuke Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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10
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Squarzoni P, Thion MS, Garel S. Neuronal and microglial regulators of cortical wiring: usual and novel guideposts. Front Neurosci 2015; 9:248. [PMID: 26236185 PMCID: PMC4505395 DOI: 10.3389/fnins.2015.00248] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022] Open
Abstract
Neocortex functioning relies on the formation of complex networks that begin to be assembled during embryogenesis by highly stereotyped processes of cell migration and axonal navigation. The guidance of cells and axons is driven by extracellular cues, released along by final targets or intermediate targets located along specific pathways. In particular, guidepost cells, originally described in the grasshopper, are considered discrete, specialized cell populations located at crucial decision points along axonal trajectories that regulate tract formation. These cells are usually early-born, transient and act at short-range or via cell-cell contact. The vast majority of guidepost cells initially identified were glial cells, which play a role in the formation of important axonal tracts in the forebrain, such as the corpus callosum, anterior, and post-optic commissures as well as optic chiasm. In the last decades, tangential migrating neurons have also been found to participate in the guidance of principal axonal tracts in the forebrain. This is the case for several examples such as guideposts for the lateral olfactory tract (LOT), corridor cells, which open an internal path for thalamo-cortical axons and Cajal-Retzius cells that have been involved in the formation of the entorhino-hippocampal connections. More recently, microglia, the resident macrophages of the brain, were specifically observed at the crossroads of important neuronal migratory routes and axonal tract pathways during forebrain development. We furthermore found that microglia participate to the shaping of prenatal forebrain circuits, thereby opening novel perspectives on forebrain development and wiring. Here we will review the last findings on already known guidepost cell populations and will discuss the role of microglia as a potentially new class of atypical guidepost cells.
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Affiliation(s)
- Paola Squarzoni
- Centre National de la Recherche Scientifique UMR8197, Ecole Normale Supérieure, Institut de Biologie, Institut National de la Santé et de la Recherche Médicale U1024 Paris, France
| | - Morgane S Thion
- Centre National de la Recherche Scientifique UMR8197, Ecole Normale Supérieure, Institut de Biologie, Institut National de la Santé et de la Recherche Médicale U1024 Paris, France
| | - Sonia Garel
- Centre National de la Recherche Scientifique UMR8197, Ecole Normale Supérieure, Institut de Biologie, Institut National de la Santé et de la Recherche Médicale U1024 Paris, France
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11
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Rama N, Dubrac A, Mathivet T, Ní Chárthaigh RA, Genet G, Cristofaro B, Pibouin-Fragner L, Ma L, Eichmann A, Chédotal A. Slit2 signaling through Robo1 and Robo2 is required for retinal neovascularization. Nat Med 2015; 21:483-91. [PMID: 25894826 PMCID: PMC4819398 DOI: 10.1038/nm.3849] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/25/2015] [Indexed: 02/07/2023]
Abstract
Ocular neovascular diseases are a leading cause of blindness. Vascular endothelial growth factor (VEGF) blockade improves vision, but not all individuals respond to anti-VEGF treatment, making additional means to prevent neovascularization necessary. Slit-family proteins (Slits) are ligands of Roundabout (Robo) receptors that repel developing axons in the nervous system. Robo1 expression is altered in ocular neovascular diseases, and previous in vitro studies have reported both pro- and anti-angiogenic effects of Slits. However, genetic evidence supporting a role for Slits in ocular neovascularization is lacking. Here we generated conditional knockout mice deficient in various Slit and Robo proteins and found that Slit2 potently and selectively promoted angiogenesis via Robo1 and Robo2 in mouse postnatal retina and in a model of ocular neovascular disease. Mechanistically, Slit2 acting through Robo1 and Robo2 promoted the migration of endothelial cells. These receptors are required for both Slit2- and VEGF-induced Rac1 activation and lamellipodia formation. Thus, Slit2 blockade could potentially be used therapeutically to inhibit angiogenesis in individuals with ocular neovascular disease.
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Affiliation(s)
- Nicolas Rama
- 1] INSERM UMR S968, Institut de la Vision, Paris, France. [2] Université Pierre et Marie Curie, Sorbonne Universités, Paris, France. [3] UMR 7210, CNRS, Paris, France
| | - Alexandre Dubrac
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Thomas Mathivet
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Róisín-Ana Ní Chárthaigh
- 1] INSERM UMR S968, Institut de la Vision, Paris, France. [2] Université Pierre et Marie Curie, Sorbonne Universités, Paris, France. [3] UMR 7210, CNRS, Paris, France
| | - Gael Genet
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Brunella Cristofaro
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | | | - Le Ma
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Anne Eichmann
- 1] Section of Cardiovascular Medicine, Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France. [3] Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Alain Chédotal
- 1] INSERM UMR S968, Institut de la Vision, Paris, France. [2] Université Pierre et Marie Curie, Sorbonne Universités, Paris, France. [3] UMR 7210, CNRS, Paris, France
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12
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Abstract
Roundabout receptors (Robo) and their Slit ligands were discovered in the 1990s and found to be key players in axon guidance. Slit was initially described s an extracellular matrix protein that was expressed by midline glia in Drosophila. A few years later, it was shown that, in vertebrates and invertebrates, Slits acted as chemorepellents for axons crossing the midline. Robo proteins were originally discovered in Drosophila in a mutant screen for genes involved in the regulation of midline crossing. This ligand-receptor pair has since been implicated in a variety of other neuronal and non-neuronal processes ranging from cell migration to angiogenesis, tumourigenesis and even organogenesis of tissues such as kidneys, lungs and breasts.
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13
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Borrell V, Cárdenas A, Ciceri G, Galcerán J, Flames N, Pla R, Nóbrega-Pereira S, García-Frigola C, Peregrín S, Zhao Z, Ma L, Tessier-Lavigne M, Marín O. Slit/Robo signaling modulates the proliferation of central nervous system progenitors. Neuron 2012; 76:338-52. [PMID: 23083737 PMCID: PMC4443924 DOI: 10.1016/j.neuron.2012.08.003] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2012] [Indexed: 11/23/2022]
Abstract
Neurogenesis relies on a delicate balance between progenitor maintenance and neuronal production. Progenitors divide symmetrically to increase the pool of dividing cells. Subsequently, they divide asymmetrically to self-renew and produce new neurons or, in some brain regions, intermediate progenitor cells (IPCs). Here we report that central nervous system progenitors express Robo1 and Robo2, receptors for Slit proteins that regulate axon guidance, and that absence of these receptors or their ligands leads to loss of ventricular mitoses. Conversely, production of IPCs is enhanced in Robo1/2 and Slit1/2 mutants, suggesting that Slit/Robo signaling modulates the transition between primary and intermediate progenitors. Unexpectedly, these defects do not lead to transient overproduction of neurons, probably because supernumerary IPCs fail to detach from the ventricular lining and cycle very slowly. At the molecular level, the role of Slit/Robo in progenitor cells involves transcriptional activation of the Notch effector Hes1. These findings demonstrate that Robo signaling modulates progenitor cell dynamics in the developing brain.
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Affiliation(s)
- Víctor Borrell
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Adrián Cárdenas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Gabriele Ciceri
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Joan Galcerán
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Nuria Flames
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Ramón Pla
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Sandrina Nóbrega-Pereira
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Cristina García-Frigola
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Sandra Peregrín
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
| | - Zhen Zhao
- Department of Cell and Neurobiology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Le Ma
- Department of Cell and Neurobiology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Marc Tessier-Lavigne
- Laboratory of Brain Development and Repair, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Oscar Marín
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain
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14
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Hirata T, Kumada T, Kawasaki T, Furukawa T, Aiba A, Conquet F, Saga Y, Fukuda A. Guidepost neurons for the lateral olfactory tract: expression of metabotropic glutamate receptor 1 and innervation by glutamatergic olfactory bulb axons. Dev Neurobiol 2012; 72:1559-76. [PMID: 22539416 DOI: 10.1002/dneu.22030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 04/22/2012] [Indexed: 12/31/2022]
Abstract
The guidepost neurons for the lateral olfactory tract, which are called lot cells, are the earliest-generated neurons in the neocortex. They migrate tangentially and ventrally further down this tract, and provide scaffolding for the olfactory bulb axons projecting into this pathway. The molecular profiles of the lot cells are largely uncharacterized. We found that lot cells specifically express metabotropic glutamate receptor subtype-1 at a very early stage of development. This receptor is functionally competent and responds to a metabotropic glutamate receptor agonist with a transient increase in the intracellular calcium ion concentration. When the glutamatergic olfactory bulb axons were electrically stimulated, lot cells responded to the stimulation with a calcium increase mainly via ionotropic glutamate receptors, suggesting potential neurotransmission between the axons and lot cells during early development. Together with the finding that lot cells themselves are glutamatergic excitatory neurons, our results provide another notable example of precocious interactions between the projecting axons and their intermediate targets.
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Affiliation(s)
- Tatsumi Hirata
- Division of Brain Function, National Institute of Genetics, Yata, Mishima, Shizuoka, Japan.
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15
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Round JE, Sun H. The adaptor protein Nck2 mediates Slit1-induced changes in cortical neuron morphology. Mol Cell Neurosci 2011; 47:265-73. [PMID: 21600986 DOI: 10.1016/j.mcn.2011.04.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 04/18/2011] [Accepted: 04/28/2011] [Indexed: 01/24/2023] Open
Abstract
Slits are multifunctional guidance cues, capable of triggering neurite repulsion, extension, or branching, depending on cell type and developmental context. While the Robo family of Slit receptors is a well-established mediator of axon repulsion, a role for Robos in Slit-mediated neurite growth and branching is not well defined, and the signaling molecules that link Robo to the cytoskeletal changes that drive neurite outgrowth are not well characterized in vertebrates. We show that Slit stimulates cortical dendrite branching, and we report that Slit also triggers a robust increase in the length of cortical axons in vitro. Moreover, neurons derived from Robo1; Robo2 deficient mice do not display an increase in neurite length, indicating that endogenous Robos mediate Slit's growth-promoting effects on both axons and dendrites. We also demonstrate that the SH2/SH3 adaptor proteins Nck1 and Nck2 bind to Robo via an atypical SH3-mediated mechanism. Furthermore, we show that only Nck2 is required for the Slit-induced changes in cortical neuron morphology in vitro. These findings indicate a specific role for Nck2 in linking Robo activation to the cytoskeleton rearrangements that shape cortical neuron morphology.
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Affiliation(s)
- Jennifer E Round
- Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06520, United States.
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16
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Timing of neurogenesis is a determinant of olfactory circuitry. Nat Neurosci 2011; 14:331-7. [PMID: 21297629 PMCID: PMC3046046 DOI: 10.1038/nn.2754] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 01/11/2011] [Indexed: 02/07/2023]
Abstract
An odorant receptor map in mammals, that is constructed by the glomerular coalescence of sensory neuron axons in the olfactory bulb, is essential for proper odor information processing. However, how this map is linked with olfactory cortex is unknown. Here, we use a battery of methods, including various markers of cell division in combination with tracers of neuronal connections and time-lapse live imaging, to show that early- and late-generated mouse mitral cells become differentially distributed within the dorsal and ventral subdivisions of the odorant receptor map. In addition, we demonstrate that the late-generated mitral cells extend significantly stronger projections to the olfactory tubercle than the early-generated. Together, these data indicate that the odorant receptor map is developmentally linked to the olfactory cortices in part by the birthdate of mitral cells. This endows different olfactory cortical regions a role to process information from distinct regions of odorant receptor map.
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17
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Xu Y, Wen-Liang L, Li F, Feng G, Yong-Jie M. Slit2/Robo1 signaling in glioma migration and invasion. Neurosci Bull 2010; 26:474-8. [PMID: 21113198 PMCID: PMC5560338 DOI: 10.1007/s12264-010-0730-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 09/06/2010] [Indexed: 11/25/2022] Open
Abstract
Slit2/Robo1 is a conserved ligand-receptor system, which greatly affects the distribution, migration, axon guidance and branching of neuron cells. Slit2 and its transmembrane receptor Robo1 have different distribution patterns in gliomas. The expression of Slit2 is at very low levels in pilocytic astrocytoma, fibrillary astrocytoma and glioblastoma, while Robo1 is highly expressed in different grades of gliomas at both mRNA and protein levels. Acquisition of insidious invasiveness by malignant glioma cells involves multiple genetic alterations in signaling pathways. Although the specific mechanisms of tumor-suppressive effect of Slit2/Robo1 have not been elucidated, it has been proved that Slit2/Robo1 signaling inhibits glioma cell migration and invasion by inactivation of Cdc42-GTP. With the research development on the molecular mechanisms of Slit2/Robo1 signaling in glioma invasion and migration, Slit2/Robo1 signaling may become a potential target for glioma prevention and treatment.
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Affiliation(s)
- Yun Xu
- Central Laboratory of Oncology Department, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin, 300060 China
| | - Li Wen-Liang
- Department of Neurosurgery, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin, 300060 China
| | - Fu Li
- Department of Breast Pathology, Tianjin Medical University Cancer Institute and Hospital, Key Laboratory of Breast Cancer Prevention and Therapy of the Ministry of Education, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin, 300060 China
| | - Gu Feng
- Department of Breast Pathology, Tianjin Medical University Cancer Institute and Hospital, Key Laboratory of Breast Cancer Prevention and Therapy of the Ministry of Education, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin, 300060 China
| | - Ma Yong-Jie
- Central Laboratory of Oncology Department, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin, 300060 China
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18
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Ahmed G, Shinmyo Y, Naser IB, Hossain M, Song X, Tanaka H. Olfactory bulb axonal outgrowth is inhibited by draxin. Biochem Biophys Res Commun 2010; 398:730-4. [PMID: 20621059 DOI: 10.1016/j.bbrc.2010.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 07/05/2010] [Indexed: 11/27/2022]
Abstract
Olfactory bulb (OB) projection neurons receive sensory input from olfactory receptor neurons and precisely relay it through their axons to the olfactory cortex. Thus, olfactory bulb axonal tracts play an important role in relaying information to the higher order of olfactory structures in the brain. Several classes of axon guidance molecules influence the pathfinding of the olfactory bulb axons. Draxin, a recently identified novel class of repulsive axon guidance protein, is essential for the formation of forebrain commissures and can mediate repulsion of diverse classes of neurons from chickens and mice. In this study, we have investigated the draxin expression pattern in the mouse telencephalon and its guidance functions for OB axonal projection to the telencephalon. We have found that draxin is expressed in the neocortex and septum at E13 and E17.5 when OB projection neurons form the lateral olfactory tract (LOT) rostrocaudally along the ventrolateral side of the telencephalon. Draxin inhibits axonal outgrowth from olfactory bulb explants in vitro and draxin-binding activity in the LOT axons in vivo is detected. The LOT develops normally in draxin-/- mice despite subtle defasciculation in the tract of these mutants. These results suggest that draxin functions as an inhibitory guidance cue for OB axons and indicate its contribution to the formation of the LOT.
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Affiliation(s)
- Giasuddin Ahmed
- Division of Developmental Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
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19
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Ypsilanti AR, Zagar Y, Chédotal A. Moving away from the midline: new developments for Slit and Robo. Development 2010; 137:1939-52. [DOI: 10.1242/dev.044511] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In most tissues, the precise control of cell migration and cell-cell interaction is of paramount importance to the development of a functional structure. Several families of secreted molecules have been implicated in regulating these aspects of development, including the Slits and their Robo receptors. These proteins have well described roles in axon guidance but by influencing cell polarity and adhesion, they participate in many developmental processes in diverse cell types. We review recent progress in understanding both the molecular mechanisms that modulate Slit/Robo expression and their functions in neural and non-neural tissue.
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Affiliation(s)
- Athena R. Ypsilanti
- INSERM, U968, Paris F-75012, France
- UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, 17 rue Moreau, Paris F-75012, France
- CNRS, UMR_7210, Paris F-75012, France
| | - Yvrick Zagar
- INSERM, U968, Paris F-75012, France
- UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, 17 rue Moreau, Paris F-75012, France
- CNRS, UMR_7210, Paris F-75012, France
| | - Alain Chédotal
- INSERM, U968, Paris F-75012, France
- UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, 17 rue Moreau, Paris F-75012, France
- CNRS, UMR_7210, Paris F-75012, France
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20
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Abstract
The mammalian brain is the most complex organ in the body. It controls all aspects of our bodily functions and interprets the world around us through our senses. It defines us as human beings through our memories and our ability to plan for the future. Crucial to all these functions is how the brain is wired in order to perform these tasks. The basic map of brain wiring occurs during embryonic and postnatal development through a series of precisely orchestrated developmental events regulated by specific molecular mechanisms. Below we review the most important features of mammalian brain wiring derived from work in both mammals and in nonmammalian species. These mechanisms are highly conserved throughout evolution, simply becoming more complex in the mammalian brain. This fascinating area of biology is uncovering the essence of what makes the mammalian brain able to perform the everyday tasks we take for granted, as well as those which give us the ability for extraordinary achievement.
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Affiliation(s)
- Alain Chédotal
- INSERM, UMRS_968, Institut de la Vision, Department of Development, 17 rue Moreau, Paris, France
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21
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de Castro F. Wiring Olfaction: The Cellular and Molecular Mechanisms that Guide the Development of Synaptic Connections from the Nose to the Cortex. Front Neurosci 2009; 3:52. [PMID: 20582279 PMCID: PMC2858608 DOI: 10.3389/neuro.22.004.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 11/04/2009] [Indexed: 12/27/2022] Open
Abstract
Within the central nervous system, the olfactory system fascinates by its developmental and physiological particularities, and is one of the most studied models to understand the mechanisms underlying the guidance of growing axons to their appropriate targets. A constellation of contact-mediated (laminins, CAMs, ephrins, etc.) and secreted mechanisms (semaphorins, slits, growth factors, etc.) are known to play different roles in the establishment of synaptic interactions between the olfactory epithelium, olfactory bulb (OB) and olfactory cortex. Specific mechanisms of this system (including the amazing family of about 1000 different olfactory receptors) have been also proposed. In the last years, different reviews have focused in partial sights, specially in the mechanisms involved in the formation of the olfactory nerve, but a detailed review of the mechanisms implicated in the development of the connections among the different olfactory structures (olfactory epithelium, OB, olfactory cortex) remains to be written. In the present work, we afford this systematic review: the different cellular and molecular mechanisms which rule the formation of the olfactory nerve, the lateral olfactory tract and the intracortical connections, as well as the few data available regarding the accessory olfactory system. These mechanisms are compared, and the implications of the differences and similarities discussed in this fundamental scenario of ontogeny.
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Affiliation(s)
- Fernando de Castro
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
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22
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Prince JEA, Cho JH, Dumontier E, Andrews W, Cutforth T, Tessier-Lavigne M, Parnavelas J, Cloutier JF. Robo-2 controls the segregation of a portion of basal vomeronasal sensory neuron axons to the posterior region of the accessory olfactory bulb. J Neurosci 2009; 29:14211-22. [PMID: 19906969 PMCID: PMC2821732 DOI: 10.1523/jneurosci.3948-09.2009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 09/23/2009] [Accepted: 09/25/2009] [Indexed: 11/21/2022] Open
Abstract
The ability of sensory systems to detect and process information from the environment relies on the elaboration of precise connections between sensory neurons in the periphery and second order neurons in the CNS. In mice, the accessory olfactory system is thought to regulate a wide variety of social and sexual behaviors. The expression of the Slit receptors Robo-1 and Robo-2 in vomeronasal sensory neurons (VSNs) suggests they may direct the stereotypic targeting of their axons to the accessory olfactory bulb (AOB). Here, we have examined the roles of Robo-1 and Robo-2 in the formation of connections by VSN axons within the AOB. While Robo-1 is not necessary for the segregation of VSN axons within the anterior and posterior regions of the AOB, Robo-2 is required for the targeting of some basal VSN axons to the posterior region of the AOB but is dispensable for the fasciculation of VSN axons. Furthermore, the specific ablation of Robo-2 expression in VSNs leads to mistargeting of a portion of basal VSN axons to the anterior region of the AOB, indicating that Robo-2 expression is required on projecting VSN axons. Together, these results identify Robo-2 as a receptor that controls the targeting of basal VSN axons to the posterior AOB.
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Affiliation(s)
- Janet E. A. Prince
- Montreal Neurological Institute, Centre for Neuronal Survival, Montréal, Québec H3A 2B4, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Jin Hyung Cho
- Montreal Neurological Institute, Centre for Neuronal Survival, Montréal, Québec H3A 2B4, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Emilie Dumontier
- Montreal Neurological Institute, Centre for Neuronal Survival, Montréal, Québec H3A 2B4, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - William Andrews
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Tyler Cutforth
- Department of Molecular, Cell & Developmental Biology, University of California, Santa Cruz, Santa Cruz, California 95064, and
| | | | - John Parnavelas
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Jean-François Cloutier
- Montreal Neurological Institute, Centre for Neuronal Survival, Montréal, Québec H3A 2B4, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
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23
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Tamada A, Kumada T, Zhu Y, Matsumoto T, Hatanaka Y, Muguruma K, Chen Z, Tanabe Y, Torigoe M, Yamauchi K, Oyama H, Nishida K, Murakami F. Crucial roles of Robo proteins in midline crossing of cerebellofugal axons and lack of their up-regulation after midline crossing. Neural Dev 2008; 3:29. [PMID: 18986510 PMCID: PMC2613388 DOI: 10.1186/1749-8104-3-29] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 11/05/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Robo1, Robo2 and Rig-1 (Robo3), members of the Robo protein family, are candidate receptors for the chemorepellents Slit and are known to play a crucial role in commissural axon guidance in the spinal cord. However, their roles at other axial levels remain unknown. Here we examine expression of Robo proteins by cerebellofugal (CF) commissural axons in the rostral hindbrain and investigate their roles in CF axon pathfinding by analysing Robo knockout mice. RESULTS We analysed the expression of Robo proteins by CF axons originating from deep cerebellar neurons in rodent embryos, focusing on developmental stages of their midline crossing and post-crossing navigation. At the stage of CF axon midline crossing, mRNAs of Robo1 and Robo2 are expressed in the nuclear transitory zone of the cerebellum, where the primordium of the deep cerebellar nuclei are located, supporting the notion that CF axons express Robo1 and Robo2. Indeed, immunohistochemical analysis of CF axons labelled by electroporation to deep cerebellar nuclei neurons indicates that Robo1 protein, and possibly also Robo2 protein, is expressed by CF axons crossing the midline. However, weak or no expression of these proteins is found on the longitudinal portion of CF axons. In Robo1/2 double knockout mice, many CF axons reach the midline but fail to exit it. We find that CF axons express Rig-1 (Robo3) before they reach the midline but not after the longitudinal turn. Consistent with this in vivo observation, axons elicited from a cerebellar explant in co-culture with a floor plate explant express Rig-1. In Rig-1 deficient mouse embryos, CF axons appear to project ipsilaterally without reaching the midline. CONCLUSION These results indicate that Robo1, Robo2 or both are required for midline exit of CF axons. In contrast, Rig-1 is required for their approach to the midline. However, post-crossing up-regulation of these proteins, which plays an important role in spinal commissural axon guidance, does not appear to be required for the longitudinal navigation of CF axons after midline crossing. Our results illustrate that although common mechanisms operate for midline crossing at different axial levels, significant variation exists in post-crossing navigation.
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MESH Headings
- Animals
- Axons/metabolism
- Axons/physiology
- Blotting, Western
- Cerebellum/embryology
- Cerebellum/metabolism
- Female
- Gene Expression Regulation, Developmental
- Genetic Vectors/genetics
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Immunohistochemistry
- In Situ Hybridization
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Membrane Proteins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Fluorescence
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/physiology
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, Cell Surface
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Immunologic/physiology
- Rhombencephalon/embryology
- Rhombencephalon/metabolism
- Tissue Culture Techniques
- Transfection
- Roundabout Proteins
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Affiliation(s)
- Atsushi Tamada
- National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan
- RIKEN Brain Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Tatsuro Kumada
- National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan
- CREST, JST (Japan Science and Technology), Kawauguchi, 332-0012, Japan
- Hamamatsu University School of Medicine, 1-20-1, Handayama, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Yan Zhu
- SORST, JST, Kawauguchi, 332-0012, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Tomoko Matsumoto
- SORST, JST, Kawauguchi, 332-0012, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Yumiko Hatanaka
- National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan
- CREST, JST (Japan Science and Technology), Kawauguchi, 332-0012, Japan
- Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Keiko Muguruma
- CREST, JST (Japan Science and Technology), Kawauguchi, 332-0012, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
- RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
| | - Zhe Chen
- Division of Research, Genentech Inc, South San Francisco, CA 94080, USA
| | - Yasuto Tanabe
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Makio Torigoe
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Kenta Yamauchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Hiroshi Oyama
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Kazuhiko Nishida
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
| | - Fujio Murakami
- National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan
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24
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Farmer WT, Altick AL, Nural HF, Dugan JP, Kidd T, Charron F, Mastick GS. Pioneer longitudinal axons navigate using floor plate and Slit/Robo signals. Development 2008; 135:3643-53. [PMID: 18842816 PMCID: PMC2768610 DOI: 10.1242/dev.023325] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Longitudinal axons transmit all signals between the brain and spinal cord. Their axon tracts through the brain stem are established by a simple set of pioneer axons with precise trajectories parallel to the floor plate. To identify longitudinal guidance mechanisms in vivo, the overall role of floor plate tissue and the specific roles of Slit/Robo signals were tested. Ectopic induction or genetic deletion of the floor plate diverted longitudinal axons into abnormal trajectories. The expression patterns of the diffusible cues of the Slit family were altered in the floor plate experiments, suggesting their involvement in longitudinal guidance. Genetic tests of Slit1 and Slit2, and the Slit receptors Robo1 and Robo2 were carried out in mutant mice. Slit1;Slit2 double mutants had severe longitudinal errors, particularly for ventral axons, including midline crossing and wandering longitudinal trajectories. Robo1 and Robo2 were largely genetically redundant, and neither appeared to specify specific tract positions. However, combined Robo1 and Robo2 mutations strongly disrupted each pioneer tract. Thus, pioneer axons depend on long-range floor plate cues, with Slit/Robo signaling required for precise longitudinal trajectories.
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Affiliation(s)
- W. Todd Farmer
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Amy L. Altick
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | | | - James P. Dugan
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Thomas Kidd
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Frédéric Charron
- Molecular Biology of Neural Development, Institut de recherches cliniques de Montréal (IRCM), 110 Pine Avenue West, Montreal, Quebec H2W 1R7, Canada
| | - Grant S. Mastick
- Department of Biology, University of Nevada, Reno, NV 89557, USA
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25
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Di Meglio T, Nguyen-Ba-Charvet KT, Tessier-Lavigne M, Sotelo C, Chédotal A. Molecular mechanisms controlling midline crossing by precerebellar neurons. J Neurosci 2008; 28:6285-94. [PMID: 18562598 PMCID: PMC6670887 DOI: 10.1523/jneurosci.0078-08.2008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Revised: 04/18/2008] [Accepted: 05/07/2008] [Indexed: 11/21/2022] Open
Abstract
Precerebellar neurons of the inferior olive (IO) and lateral reticular nucleus (LRN) migrate tangentially from the rhombic lip toward the floor plate following parallel pathways. This process is thought to involve netrin-1 attraction. However, whereas the cell bodies of LRN neurons cross the midline, IO neurons are unable to do so. In many systems and species, axon guidance and cell migration at the midline are controlled by Slits and their receptor Robos. We showed previously that precerebellar axons and neurons do not cross the midline in the absence of the Robo3 receptor. To determine whether this signaling by Slits and the two other Robo receptors, Robo1 and Robo2, also regulates precerebellar neuron behavior at the floor plate, we studied the phenotype of Slit1/2 and Robo1/2/3 compound mutants. Our results showed that many IO neurons can cross the midline in absence of Slit1/2 or Robo1/2, supporting a role for midline repellents in guiding precerebellar neurons. We also show that these molecules control the development of the lamellation of the inferior olivary complex. Last, the analysis of Robo1/2/3 triple mutants suggests that Robo3 inhibits Robo1/2 repulsion in precrossing LRN axons but not in IO axons in which it has a dominant and distinct function.
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Affiliation(s)
- Thomas Di Meglio
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 7102
- Université Pierre et Marie Curie, UMR 7102, F-75005 Paris, France
| | - Kim T. Nguyen-Ba-Charvet
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 7102
- Université Pierre et Marie Curie, UMR 7102, F-75005 Paris, France
| | | | - Constantino Sotelo
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 7102
- Université Pierre et Marie Curie, UMR 7102, F-75005 Paris, France
- Cátedra de Neurobiología del Desarrollo “Remedios Caro Almela,” Instituto de Neurociencias de Alicante, Universidad Miguel Hernández de Elche–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Alicante, Spain
| | - Alain Chédotal
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 7102
- Université Pierre et Marie Curie, UMR 7102, F-75005 Paris, France
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26
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Geisen MJ, Meglio TD, Pasqualetti M, Ducret S, Brunet JF, Chedotal A, Rijli FM. Hox paralog group 2 genes control the migration of mouse pontine neurons through slit-robo signaling. PLoS Biol 2008; 6:e142. [PMID: 18547144 PMCID: PMC2422855 DOI: 10.1371/journal.pbio.0060142] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 04/28/2008] [Indexed: 12/18/2022] Open
Abstract
The pontine neurons (PN) represent a major source of mossy fiber projections to the cerebellum. During mouse hindbrain development, PN migrate tangentially and sequentially along both the anteroposterior (AP) and dorsoventral (DV) axes. Unlike DV migration, which is controlled by the Netrin-1/Dcc attractive pathway, little is known about the molecular mechanisms guiding PN migration along the AP axis. Here, we show that Hoxa2 and Hoxb2 are required both intrinsically and extrinsically to maintain normal AP migration of subsets of PN, by preventing their premature ventral attraction towards the midline. Moreover, the migration defects observed in Hoxa2 and Hoxb2 mutant mice were phenocopied in compound Robo1;Robo2, Slit1;Slit2, and Robo2;Slit2 knockout animals, indicating that these guidance molecules act downstream of Hox genes to control PN migration. Indeed, using chromatin immunoprecipitation assays, we further demonstrated that Robo2 is a direct target of Hoxa2 in vivo and that maintenance of high Robo and Slit expression levels was impaired in Hoxa2 mutant mice. Lastly, the analysis of Phox2b-deficient mice indicated that the facial motor nucleus is a major Slit signaling source required to prevent premature ventral migration of PN. These findings provide novel insights into the molecular control of neuronal migration from transcription factor to regulation of guidance receptor and ligand expression. Specifically, they address the question of how exposure to multiple guidance cues along the AP and DV axes is regulated at the transcriptional level and in turn translated into stereotyped migratory responses during tangential migration of neurons in the developing mammalian brain.
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Affiliation(s)
- Marc J Geisen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, UMR 7104, CU de Strasbourg, Illkirch, France
| | - Thomas Di Meglio
- CNRS UMR 7102 Université Pierre et Marie Curie–Paris 6, Paris, France
| | - Massimo Pasqualetti
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, UMR 7104, CU de Strasbourg, Illkirch, France
| | - Sebastien Ducret
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, UMR 7104, CU de Strasbourg, Illkirch, France
- Friedrich Miescher Institute, Basel, Switzerland
| | | | - Alain Chedotal
- CNRS UMR 7102 Université Pierre et Marie Curie–Paris 6, Paris, France
| | - Filippo M Rijli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, UMR 7104, CU de Strasbourg, Illkirch, France
- Friedrich Miescher Institute, Basel, Switzerland
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Nguyen-Ba-Charvet KT, Di Meglio T, Fouquet C, Chédotal A. Robos and slits control the pathfinding and targeting of mouse olfactory sensory axons. J Neurosci 2008; 28:4244-9. [PMID: 18417704 PMCID: PMC6670299 DOI: 10.1523/jneurosci.5671-07.2008] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 02/18/2008] [Accepted: 03/13/2008] [Indexed: 12/13/2022] Open
Abstract
Odorants are detected by olfactory receptor neurons (ORNs) located in the olfactory epithelium. In mice, ORNs expressing the same odorant receptor (OR) project to a single glomerulus out of 1800 in the olfactory bulb (OB). It has been proposed that OR-derived cAMP signals guide ORN axons to their glomeruli rather than OR themselves. Recently, it has also been shown that the axon guidance molecule Slit1 and its receptor Robo2 control the dorsoventral segregation of ORN axons as they are projecting to the OB. We have analyzed the development of olfactory projections in Slit1/Slit2 and Robo1/Robo2 single and double mutants. We show that in Robo1-/-;Robo2-/- mice, most ORN axons fail to enter the OB and instead project caudally into the diencephalon. Moreover, in these mice, ORN axons expressing the same OR project to several glomeruli at ectopic positions. Thus, Slit1, Slit2, Robo1, and Robo2 cooperate to control the convergence of ORN axons to the OB and the precise targeting of ORN axons to specific glomeruli.
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Affiliation(s)
- Kim T. Nguyen-Ba-Charvet
- Université Pierre et Marie Curie and
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7102, F-75005 Paris, France, and
| | - Thomas Di Meglio
- Université Pierre et Marie Curie and
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7102, F-75005 Paris, France, and
| | - Coralie Fouquet
- Université Pierre et Marie Curie and
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7102, F-75005 Paris, France, and
| | - Alain Chédotal
- Université Pierre et Marie Curie and
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7102, F-75005 Paris, France, and
- Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Fédération de Neurologie, F-75013 Paris, France
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28
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Plachez C, Andrews W, Liapi A, Knoell B, Drescher U, Mankoo B, Zhe L, Mambetisaeva E, Annan A, Bannister L, Parnavelas JG, Richards LJ, Sundaresan V. Robos are required for the correct targeting of retinal ganglion cell axons in the visual pathway of the brain. Mol Cell Neurosci 2008; 37:719-30. [PMID: 18272390 DOI: 10.1016/j.mcn.2007.12.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 11/24/2007] [Accepted: 12/12/2007] [Indexed: 11/26/2022] Open
Abstract
Axonal projections from the retina to the brain are regulated by molecules including the Slit family of ligands [Thompson, H., Barker, D., Camand, O., Erskine, L., 2006a. Slits contribute to the guidance of retinal ganglion cell axons in the mammalian optic tract. Dev. Biol. 296, 476-484, Thompson, H., Camand, O., Barker, D., Erskine, L., 2006b. Slit proteins regulate distinct aspects of retinal ganglion cell axon guidance within dorsal and ventral retina. J. Neurosci. 26, 8082-8091]. However, the roles of Slit receptors in mammals, (termed Robos), have not been investigated in visual system development. Here we examined Robo1 and 2 mutant mice and found that Robos regulate the correct targeting of retinal ganglion cell (RGC) axons along the entire visual projection. We noted aberrant projections of RGC axons into the cerebral cortex, an area not normally targeted by RGC axons. The optic chiasm was expanded along the rostro-caudal axis (similar to Slit mutant mice, Plump, A.S., Erskine, L., Sabatier, C., Brose, K., Epstein, C.J., Goodman, C.S., Mason, C.A., Tessier-Lavigne, M., 2002. Slit1 and Slit2 cooperate to prevent premature midline crossing of retinal axons in the mouse visual system. Neuron 33, 219-232), with ectopic crossing points, and some axons projecting caudally toward the corticospinal tract. Further, we found that axons exuberantly projected into the diencephalon. These defects were more pronounced in Robo2 than Robo1 knockout animals, implicating Robo2 as the predominant Robo receptor in visual system development.
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Affiliation(s)
- Céline Plachez
- The University of Maryland, Baltimore, School of Medicine, Baltimore, Maryland, USA
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29
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Abstract
Drosophila Slit and its vertebrate orthologues Slit1-Slit3 are secreted glycoproteins that play important roles in the development of the nervous system and other organs. Human Slits are also involved in a number of pathological situations, such as cancer and inflammation. Slits exert their effects by activating receptors of the Robo (Roundabout) family, which resemble cell adhesion molecules in their ectodomains and have large, mainly unstructured cytosolic domains. HS (heparan sulfate) is required for Slit-Robo signalling. The hallmark of Slit proteins is a tandem of four LRR (leucine-rich repeat) domains, which mediate binding to the IG (immunoglobulin-like) domains of Robos. A major question is how Slit binding is translated into the recruitment of effector molecules to the cytosolic domain of Robo. Detailed structure-function studies have shown that the second LRR domain of Slit (D2) binds to the first two IG domains of Robo, and that HS serves to stabilize the Slit-Robo interaction and is required for biological activity of Slit D2. Very recently, the crystal structure of a minimal Slit-Robo complex revealed that the IG1 domain of Robo is bound by the concave face of Slit D2, confirming earlier mutagenesis data. To define the mechanism of Robo transmembrane signalling, these structural insights will have to be complemented by new cell biology and microscopy approaches.
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Affiliation(s)
- Erhard Hohenester
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
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Shiau CE, Lwigale PY, Das RM, Wilson SA, Bronner-Fraser M. Robo2-Slit1 dependent cell-cell interactions mediate assembly of the trigeminal ganglion. Nat Neurosci 2008; 11:269-76. [PMID: 18278043 DOI: 10.1038/nn2051] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 01/18/2008] [Indexed: 11/08/2022]
Abstract
Vertebrate cranial sensory ganglia, responsible for sensation of touch, taste and pain in the face and viscera, are composed of both ectodermal placode and neural crest cells. The cellular and molecular interactions allowing generation of complex ganglia remain unknown. Here, we show that proper formation of the trigeminal ganglion, the largest of the cranial ganglia, relies on reciprocal interactions between placode and neural crest cells in chick, as removal of either population resulted in severe defects. We demonstrate that ingressing placode cells express the Robo2 receptor and early migrating cranial neural crest cells express its cognate ligand Slit1. Perturbation of this receptor-ligand interaction by blocking Robo2 function or depleting either Robo2 or Slit1 using RNA interference disrupted proper ganglion formation. The resultant disorganization mimics the effects of neural crest ablation. Thus, our data reveal a novel and essential role for Robo2-Slit1 signaling in mediating neural crest-placode interactions during trigeminal gangliogenesis.
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Affiliation(s)
- Celia E Shiau
- Division of Biology 139-74, California Institute of Technology, Pasadena, California 91125, USA
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31
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Mertsch S, Schmitz N, Jeibmann A, Geng JG, Paulus W, Senner V. Slit2 involvement in glioma cell migration is mediated by Robo1 receptor. J Neurooncol 2008; 87:1-7. [PMID: 17968499 DOI: 10.1007/s11060-007-9484-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Accepted: 10/17/2007] [Indexed: 12/31/2022]
Abstract
Slit and Robo proteins are evolutionarily conserved molecules whose interaction underlies axon guidance and neuronal precursor cell migration. During development secreted Slit proteins mediate chemorepulsive signals on cells expressing Robo receptors. Because similar molecular mechanisms may be utilized in glioma cell invasion and neuroblast migration, we studied the expression of Slit2 and its transmembrane receptor Robo1 as well as their functional role in migration in glioma cells. qRT-PCR and immunohistochemistry of human specimens revealed that Slit2 was distinctly expressed by non-neoplastic neurons, but at only very low levels in fibrillary astrocytoma and glioblastoma. Robo1 also was mainly restricted to neurons in the normal brain, whereas astrocytic tumor cells in situ as well as glioblastoma cell lines overexpressed Robo1 at mRNA and protein levels. Recombinant human Slit2 in a concentration of 0.45 nM was repulsive for glioma cell lines in a modified Boyden chamber assay. RNAi-mediated knockdown of Robo1 in glioma cell lines neutralized the repulsive effect of Slit2, demonstrating that Robo1 served as the major Slit2 receptor. Our findings suggest that a chemorepulsive effect mediated by interaction of Slit2 and Robo1 participates in glioma cell guidance in the brain.
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Affiliation(s)
- Sonja Mertsch
- Institute of Neuropathology, University Hospital Münster, Domagkstr. 19, 48149, Münster, Germany
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32
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Hou ST, Jiang SX, Smith RA. Permissive and repulsive cues and signalling pathways of axonal outgrowth and regeneration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 267:125-81. [PMID: 18544498 DOI: 10.1016/s1937-6448(08)00603-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Successful axonal outgrowth in the adult central nervous system (CNS) is central to the process of nerve regeneration and brain repair. To date, much of the knowledge on axonal guidance and outgrowth comes from studies on neuritogenesis and patterning during development where distal growth cones constantly sample the local environment and respond to specific physical and trophic influences. Opposing permissive (e.g., growth factors) and hostile signals (e.g., repulsive cues) are processed, leading to growth cone remodelling, and a concomitant restructuring of the cytoskeleton, thereby permitting pioneering extension and a potential for establishing synaptic connections. Repulsive cues, such as semaphorins, ephrins and myelin-secreted inhibitory glycoproteins, act through their respective receptors to affect the collapsing or turning of growth cones via several pathways, such as the Rho GTPases signalling which precipitates the cytoskeletal changes. One of the direct modulators of microtubules is the family of brain-specific proteins, collapsin response mediator protein (CRMP). Exciting evidence emerged recently that cleavage of CRMPs in response to injury-activated proteases, such as calpain, signals axonal retraction and neuronal death in adult post-mitotic neurons, while blocking this signal transduction prevents axonal retraction and death following excitotoxic insult and cerebral ischemia. Regeneration is minimal in injured postnatal CNS, albeit the occurrence of some limited remodelling in areas where synaptic plasticity is prevalent. Frequently in the absence of axonal regeneration, there is not only an inevitable loss of functional connections, but also a loss of neurons, such as through the actions of dependence receptors. Deciphering the cues and signalling pathways of axonal guidance and outgrowth may hold the key to fully understanding nerve regeneration and brain repair, thereby opening the way for developing potential therapeutics.
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Affiliation(s)
- Sheng T Hou
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
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