1
|
Herrera A, Menendez A, Ochoa A, Bardia L, Colombelli J, Pons S. Neurogenesis redirects β-catenin from adherens junctions to the nucleus to promote axonal growth. Development 2023; 150:dev201651. [PMID: 37519286 PMCID: PMC10482005 DOI: 10.1242/dev.201651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 07/26/2023] [Indexed: 08/01/2023]
Abstract
Here, we show that, in the developing spinal cord, after the early Wnt-mediated Tcf transcription activation that confers dorsal identity to neural stem cells, neurogenesis redirects β-catenin from the adherens junctions to the nucleus to stimulate Tcf-dependent transcription in a Wnt-independent manner. This new β-catenin activity regulates genes implicated in several aspects of contralateral axon growth, including axon guidance and adhesion. Using live imaging of ex-vivo chick neural tube, we showed that the nuclear accumulation of β-catenin and the rise in Tcf-dependent transcription both initiate before the dismantling of the adherens junctions and remain during the axon elongation process. Notably, we demonstrated that β-catenin activity in post-mitotic cells depends on TCF7L2 and is central to spinal commissural axon growth. Together, our results reveal Wnt-independent Tcf/β-catenin regulation of genes that control the growth and guidance of commissural axons in chick spinal cord.
Collapse
Affiliation(s)
- Antonio Herrera
- Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Parc Científic de Barcelona, Baldiri Reixac 10-12, Barcelona 08028, Spain
| | - Anghara Menendez
- Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Parc Científic de Barcelona, Baldiri Reixac 10-12, Barcelona 08028, Spain
| | - Andrea Ochoa
- Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Parc Científic de Barcelona, Baldiri Reixac 10-12, Barcelona 08028, Spain
| | - Lídia Bardia
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Julien Colombelli
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Sebastian Pons
- Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Parc Científic de Barcelona, Baldiri Reixac 10-12, Barcelona 08028, Spain
| |
Collapse
|
2
|
Cortés E, Pak JS, Özkan E. Structure and evolution of neuronal wiring receptors and ligands. Dev Dyn 2023; 252:27-60. [PMID: 35727136 PMCID: PMC10084454 DOI: 10.1002/dvdy.512] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 01/04/2023] Open
Abstract
One of the fundamental properties of a neuronal circuit is the map of its connections. The cellular and developmental processes that allow for the growth of axons and dendrites, selection of synaptic targets, and formation of functional synapses use neuronal surface receptors and their interactions with other surface receptors, secreted ligands, and matrix molecules. Spatiotemporal regulation of the expression of these receptors and cues allows for specificity in the developmental pathways that wire stereotyped circuits. The families of molecules controlling axon guidance and synapse formation are generally conserved across animals, with some important exceptions, which have consequences for neuronal connectivity. Here, we summarize the distribution of such molecules across multiple taxa, with a focus on model organisms, evolutionary processes that led to the multitude of such molecules, and functional consequences for the diversification or loss of these receptors.
Collapse
Affiliation(s)
- Elena Cortés
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.,The Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| | - Joseph S Pak
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.,The Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.,The Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| |
Collapse
|
3
|
Jayabal P, Zhou F, Lei X, Ma X, Blackman B, Weintraub ST, Houghton PJ, Shiio Y. NELL2-cdc42 signaling regulates BAF complexes and Ewing sarcoma cell growth. Cell Rep 2021; 36:109254. [PMID: 34233189 PMCID: PMC8312579 DOI: 10.1016/j.celrep.2021.109254] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/07/2021] [Accepted: 05/25/2021] [Indexed: 12/24/2022] Open
Abstract
BAF chromatin remodeling complexes play important roles in chromatin regulation and cancer. Here, we report that Ewing sarcoma cells are dependent on the autocrine signaling mediated by NELL2, a secreted glycoprotein that has been characterized as an axon guidance molecule. NELL2 uses Robo3 as the receptor to transmit critical growth signaling. NELL2 signaling inhibits cdc42 and upregulates BAF complexes and EWS-FLI1 transcriptional output. We demonstrate that cdc42 is a negative regulator of BAF complexes, inducing actin polymerization and complex disassembly. Furthermore, we identify NELL2highCD133highEWS-FLI1high and NELL2lowCD133lowEWS-FLI1low populations in Ewing sarcoma, which display phenotypes consistent with high and low NELL2 signaling, respectively. We show that NELL2, CD133, and EWS-FLI1 positively regulate each other and upregulate BAF complexes and cell proliferation in Ewing sarcoma. These results reveal a signaling pathway regulating critical chromatin remodeling complexes and cancer cell proliferation.
Collapse
Affiliation(s)
- Panneerselvam Jayabal
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Fuchun Zhou
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Xiufen Lei
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Xiuye Ma
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Barron Blackman
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center, San Antonio, TX 78229, USA; Mays Cancer Center, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Peter J Houghton
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA; Mays Cancer Center, The University of Texas Health Science Center, San Antonio, TX 78229, USA; Department of Molecular Medicine, The University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Yuzuru Shiio
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA; Department of Biochemistry and Structural Biology, The University of Texas Health Science Center, San Antonio, TX 78229, USA; Mays Cancer Center, The University of Texas Health Science Center, San Antonio, TX 78229, USA.
| |
Collapse
|
4
|
Alvarez S, Varadarajan SG, Butler SJ. Dorsal commissural axon guidance in the developing spinal cord. Curr Top Dev Biol 2020; 142:197-231. [PMID: 33706918 DOI: 10.1016/bs.ctdb.2020.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Commissural axons have been a key model system for identifying axon guidance signals in vertebrates. This review summarizes the current thinking about the molecular and cellular mechanisms that establish a specific commissural neural circuit: the dI1 neurons in the developing spinal cord. We assess the contribution of long- and short-range signaling while sequentially following the developmental timeline from the birth of dI1 neurons, to the extension of commissural axons first circumferentially and then contralaterally into the ventral funiculus.
Collapse
Affiliation(s)
- Sandy Alvarez
- Department of Neurobiology, University of California, Los Angeles, CA, United States; Molecular Biology Interdepartmental Doctoral Program, University of California, Los Angeles, CA, United States
| | | | - Samantha J Butler
- Department of Neurobiology, University of California, Los Angeles, CA, United States; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, United States.
| |
Collapse
|
5
|
Pak JS, DeLoughery ZJ, Wang J, Acharya N, Park Y, Jaworski A, Özkan E. NELL2-Robo3 complex structure reveals mechanisms of receptor activation for axon guidance. Nat Commun 2020; 11:1489. [PMID: 32198364 PMCID: PMC7083938 DOI: 10.1038/s41467-020-15211-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 02/24/2020] [Indexed: 11/24/2022] Open
Abstract
Axon pathfinding is critical for nervous system development, and it is orchestrated by molecular cues that activate receptors on the axonal growth cone. Robo family receptors bind Slit guidance cues to mediate axon repulsion. In mammals, the divergent family member Robo3 does not bind Slits, but instead signals axon repulsion from its own ligand, NELL2. Conversely, canonical Robos do not mediate NELL2 signaling. Here, we present the structures of NELL-Robo3 complexes, identifying a mode of ligand engagement for Robos that is orthogonal to Slit binding. We elucidate the structural basis for differential binding between NELL and Robo family members and show that NELL2 repulsive activity is a function of its Robo3 affinity and is enhanced by ligand trimerization. Our results reveal a mechanism of oligomerization-induced Robo activation for axon guidance and shed light on Robo family member ligand binding specificity, conformational variability, divergent modes of signaling, and evolution.
Collapse
Affiliation(s)
- Joseph S Pak
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, IL, 60637, USA
| | - Zachary J DeLoughery
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, 02912, USA
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI, 02912, USA
| | - Jing Wang
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, IL, 60637, USA
| | - Nischal Acharya
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, 02912, USA
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI, 02912, USA
| | - Yeonwoo Park
- Department of Human Genetics, University of Chicago, Chicago, IL, 60637, USA
| | - Alexander Jaworski
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, 02912, USA.
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI, 02912, USA.
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, IL, 60637, USA.
| |
Collapse
|
6
|
Comer JD, Alvarez S, Butler SJ, Kaltschmidt JA. Commissural axon guidance in the developing spinal cord: from Cajal to the present day. Neural Dev 2019; 14:9. [PMID: 31514748 PMCID: PMC6739980 DOI: 10.1186/s13064-019-0133-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022] Open
Abstract
During neuronal development, the formation of neural circuits requires developing axons to traverse a diverse cellular and molecular environment to establish synaptic contacts with the appropriate postsynaptic partners. Essential to this process is the ability of developing axons to navigate guidance molecules presented by specialized populations of cells. These cells partition the distance traveled by growing axons into shorter intervals by serving as intermediate targets, orchestrating the arrival and departure of axons by providing attractive and repulsive guidance cues. The floor plate in the central nervous system (CNS) is a critical intermediate target during neuronal development, required for the extension of commissural axons across the ventral midline. In this review, we begin by giving a historical overview of the ventral commissure and the evolutionary purpose of decussation. We then review the axon guidance studies that have revealed a diverse assortment of midline guidance cues, as well as genetic and molecular regulatory mechanisms required for coordinating the commissural axon response to these cues. Finally, we examine the contribution of dysfunctional axon guidance to neurological diseases.
Collapse
Affiliation(s)
- J D Comer
- Neuroscience Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA.,Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA.,Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, USA
| | - S Alvarez
- Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.,Molecular Biology Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - S J Butler
- Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - J A Kaltschmidt
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| |
Collapse
|
7
|
Abstract
The constant refinement of tests used in animal research is crucial for the scientific community. This is particularly true for the field of pain research, where ethical standards are notably sensitive. The formalin test is widely used in pain research and some of its mechanisms resemble those underlying clinical pain in humans. Immediately upon injection, formalin triggers two waves (an early and a late phase) of strong, nociceptive behaviour, characterised by licking, biting, lifting and shaking the injected paw of the animal. Although well characterised at the behaviour level, since its proposal over four decades ago, there has not been any significant refinement to the formalin test, especially those combining minimisation of animal distress and preservation of behavioural outcomes of the test. Here, we propose a modified and improved method for the formalin test. We show that anaesthetising the animal with the inhalable anaesthetic sevoflurane at the time of the injection can produce reliable, robust and reproducible results whilst animal distress during the initial phase is reduced. Importantly, our results were validated by pharmacological suppression of the behaviour during the late phase of the test with gabapentin, the anaesthetic showing no interference with the drug. In addition, we demonstrate that this is also a useful method to screen for changes in pain behaviour in response to formalin in transgenic lines.
Collapse
Affiliation(s)
- Douglas M Lopes
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London SE1 1UL, London, UK
| | - Heather L Cater
- MRC Harwell Institute, Harwell Campus, Didcot, Oxfordshire, OX11 0RD, UK
| | - Matthew Thakur
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London SE1 1UL, London, UK
| | - Sara Wells
- MRC Harwell Institute, Harwell Campus, Didcot, Oxfordshire, OX11 0RD, UK
| | - Stephen B McMahon
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London SE1 1UL, London, UK
| |
Collapse
|
8
|
Abstract
The constant refinement of tests used in animal research is crucial for the scientific community. This is particularly true for the field of pain research, where ethical standards are notably sensitive. The formalin test is widely used in pain research and some of its mechanisms resemble those underlying clinical pain in humans. Immediately upon injection, formalin triggers two waves (an early and a late phase) of strong, nociceptive behaviour, characterised by licking, biting, lifting and shaking the injected paw of the animal. Although well characterised at the behaviour level, since its proposal over four decades ago, there has not been any significant refinement to the formalin test, especially those combining minimisation of animal distress and preservation of behavioural outcomes of the test. Here, we propose a modified and improved method for the formalin test. We show that anaesthetising the animal with the inhalable anaesthetic sevoflurane at the time of the injection can produce reliable, robust and reproducible results whilst animal distress during the initial phase is reduced. Importantly, our results were validated by pharmacological suppression of the behaviour during the late phase of the test with gabapentin, the anaesthetic showing no interference with the drug. In addition, we demonstrate that this is also a useful method to screen for changes in pain behaviour in response to formalin in transgenic lines.
Collapse
Affiliation(s)
- Douglas M Lopes
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London SE1 1UL, London, UK
| | - Heather L Cater
- MRC Harwell Institute, Harwell Campus, Didcot, Oxfordshire, OX11 0RD, UK
| | - Matthew Thakur
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London SE1 1UL, London, UK
| | - Sara Wells
- MRC Harwell Institute, Harwell Campus, Didcot, Oxfordshire, OX11 0RD, UK
| | - Stephen B McMahon
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London SE1 1UL, London, UK
| |
Collapse
|
9
|
Yang T, Huang H, Shao Q, Yee S, Majumder T, Liu G. miR-92 Suppresses Robo1 Translation to Modulate Slit Sensitivity in Commissural Axon Guidance. Cell Rep 2018; 24:2694-2708.e6. [PMID: 30184503 DOI: 10.1016/j.celrep.2018.08.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 07/17/2018] [Accepted: 08/07/2018] [Indexed: 01/09/2023] Open
Abstract
Temporospatial regulation of guidance signaling is essential for axon outgrowth and pathfinding in the developing nervous system. Regulation of Robo1 levels in commissural neurons modulates Slit sensitivity facilitating proper axon guidance. The mechanisms underlying this regulation in the vertebrate nervous system are not well understood. Here, we report that miR-92, a highly conserved microRNA (miRNA), regulates chicken Robo1 expression in commissural neurons by binding to the 3' untranslated region (3' UTR) of Robo1 mRNA. miR-92 and Robo1 are differentially expressed in the developing spinal cord. miR-92 interacts with the Robo1 3'UTR to cause translational repression, but not mRNA degradation. Disruption of the miR-92/Robo1 3' UTR interaction induces premature responsiveness to Slit2 repulsion of precrossing commissural axons (CAs) in vitro and causes CA projection defects in vivo. These results indicate that miR-92 represses Robo1 expression thereby regulating Slit sensitivity to control CA projection and midline crossing.
Collapse
Affiliation(s)
- Tao Yang
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft St., Toledo, OH 43606, USA
| | - Huai Huang
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft St., Toledo, OH 43606, USA
| | - Qiangqiang Shao
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft St., Toledo, OH 43606, USA
| | - Shirley Yee
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft St., Toledo, OH 43606, USA
| | - Tanushree Majumder
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft St., Toledo, OH 43606, USA
| | - Guofa Liu
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft St., Toledo, OH 43606, USA.
| |
Collapse
|
10
|
CD30 Is Highly Expressed in Chronic Obstructive Pulmonary Disease and Induces the Pulmonary Vascular Remodeling. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3261436. [PMID: 29984229 PMCID: PMC6015698 DOI: 10.1155/2018/3261436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 03/26/2018] [Indexed: 11/18/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is one of the common and underdiagnosed diseases with the highest morbidity and mortality in the world. The development of COPD can lead to pulmonary vascular remodeling and pulmonary hypertension, further causing the occurrence of pulmonary heart disease. Therefore, attenuation of pulmonary vascular remodeling and pulmonary hypertension caused by COPD can significantly delay cardiovascular complications. In the study, we firstly found that the expression of CD30 and CD30L was increased in COPD. Importantly, the serum CD30L levels were significantly higher in patients with stable COPD relative to those with acute exacerbation of COPD (AECOPD). This suggested that CD30 might be related to the development of COPD. In addition, we found that the expression of CD30 in the COPD rat model was significantly increased compared with control group. And treatment with the anti-CD30 antibody reduced the serum concentration and tissue expression of CD30 in rat. Importantly, anti-CD30 antibody alleviated pulmonary vascular remodeling in COPD model rats. This suggested that CD30 played an important role in the course of COPD. Finally, we found that, in the HPASMC and HPAEC cell lines, CD30 can affect the cell viability and cell migration and inhibited hypoxia-induced cell apoptosis in a concentration-dependent manner. We also found CD30 induced extracellular matrix formation through decreasing the expression of MMP-2, thus promoting the pulmonary vascular remodeling. The study indicated that CD30 and CD30L were involved in pulmonary vascular remodeling and inflammatory response in COPD. Altogether, CD30 might be a marker for the early diagnosis and progression of COPD.
Collapse
|
11
|
Wang J, Ding M. Robo and Ror function in a common receptor complex to regulate Wnt-mediated neurite outgrowth in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2018; 115:E2254-E2263. [PMID: 29463707 PMCID: PMC5877952 DOI: 10.1073/pnas.1717468115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Growing axons are exposed to various guidance cues en route to their targets, but the mechanisms that govern the response of growth cones to combinations of signals remain largely elusive. Here, we found that the sole Robo receptor, SAX-3, in Caenorhabditis elegans functions as a coreceptor for Wnt/CWN-2 molecules. SAX-3 binds to Wnt/CWN-2 and facilitates the membrane recruitment of CWN-2. SAX-3 forms a complex with the Ror/CAM-1 receptor and its downstream effector Dsh/DSH-1, promoting signal transduction from Wnt to Dsh. sax-3 functions in Wnt-responsive cells and the SAX-3 receptor is restricted to the side of the cell from which the neurite is extended. DSH-1 has a similar asymmetric distribution, which is disrupted by sax-3 mutation. Taking these results together, we propose that Robo receptor can function as a Wnt coreceptor to regulate Wnt-mediated biological processes in vivo.
Collapse
Affiliation(s)
- Jiaming Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101 Beijing, China
- Biological Science Department, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Mei Ding
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101 Beijing, China;
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
12
|
Yom-Tov G, Barak R, Matalon O, Barda-Saad M, Guez-Haddad J, Opatowsky Y. Robo Ig4 Is a Dimerization Domain. J Mol Biol 2017; 429:3606-3616. [PMID: 29017837 DOI: 10.1016/j.jmb.2017.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/02/2017] [Accepted: 10/02/2017] [Indexed: 01/06/2023]
Abstract
Robo receptors play pivotal roles in axonal guidance as well as in neurogenesis, angiogenesis, cell migration, and cancer progression and invasiveness. They are considered to be attractive drug targets for the treatment of cancer, ocular neovascular disorders, chronic kidney diseases, and more. Despite their great importance, the mechanisms by which Robo receptors switch from their "off" to "on" states remain obscure. One possibility involves a monomer-to-dimer or dimer-to-monomer transition that facilitates the recruitment and activation of enzymatic effectors to instigate intracellular signaling. However, it is not known which domains mediate Robo dimerization, or the structural properties of the dimeric interactions. Here, we identify the extracellular Ig4 (D4) as a Robo dimerization domain. We have determined the crystal structure of the tandem Ig4-5 domains (D4-5) of human Robo2 and found that a hydrophobic surface on D4 mediates close homotypic contacts with a reciprocal D4. Analytical ultracentrifugation measurements of intact and mutated D4-5 shows that dimerization through the D4 interface is specific and has a dimerization dissociation constant of 16.9μM in solution. Direct fluorescence resonance energy transfer dimerization measurements in HEK293 cells corroborate the dimerization of transmembrane hRobo2 through D4, and a functional COS-7 cell collapse assay links D4-mediated dimerization with Robo intracellular signaling. The high level of conservation in the D4 dimerization interface throughout all Robo orthologs and paralogs implies that D4-mediated dimerization is a central hallmark in Robo activation and signaling.
Collapse
Affiliation(s)
- Galit Yom-Tov
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Reut Barak
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Omri Matalon
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Mira Barda-Saad
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Julia Guez-Haddad
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yarden Opatowsky
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| |
Collapse
|
13
|
Horizontal Gaze Palsy and Progressive Scoliosis With ROBO 3 Mutations in Patients From Cape Verde. J Neuroophthalmol 2017; 37:162-165. [DOI: 10.1097/wno.0000000000000455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
14
|
Friocourt F, Chédotal A. The Robo3 receptor, a key player in the development, evolution, and function of commissural systems. Dev Neurobiol 2017; 77:876-890. [DOI: 10.1002/dneu.22478] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 12/04/2016] [Accepted: 12/06/2016] [Indexed: 12/15/2022]
Affiliation(s)
- François Friocourt
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision; 17 Rue Moreau Paris 75012 France
| | - Alain Chédotal
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision; 17 Rue Moreau Paris 75012 France
| |
Collapse
|
15
|
de Ramon Francàs G, Zuñiga NR, Stoeckli ET. The spinal cord shows the way - How axons navigate intermediate targets. Dev Biol 2016; 432:43-52. [PMID: 27965053 DOI: 10.1016/j.ydbio.2016.12.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 11/26/2016] [Accepted: 12/01/2016] [Indexed: 12/13/2022]
Abstract
Functional neural circuits depend on the establishment of specific connections between neurons and their target cells. To this end, many axons have to travel long distances to reach their target cells during development. Studies addressing the molecular mechanisms of axon guidance have to overcome the complexity of subpopulation-specific requirements with respect to pathways, guidance cues, and target recognition. Compared to the brain, the relatively simple structure of the spinal cord provides an advantage for experimental studies of axon guidance mechanisms. Therefore, the so far best understood model for axon guidance is the dI1 population of dorsal interneurons of the spinal cord. They extend their axons ventrally towards the floor plate. After midline crossing, they turn rostrally along the contralateral floor-plate border. Despite the fact that the trajectory of dI1 axons seems to be rather simple, the number of axon guidance molecules involved in the decisions taken by these axons is bewildering. Because guidance molecules and mechanisms are conserved throughout the developing nervous system, we can generalize what we have learned about the navigation of the floor plate as an intermediate target for commissural axons to the brain.
Collapse
Affiliation(s)
- Gemma de Ramon Francàs
- University of Zurich, Department of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Nikole R Zuñiga
- University of Zurich, Department of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Esther T Stoeckli
- University of Zurich, Department of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| |
Collapse
|
16
|
Jin X, Shin YJ, Riew TR, Choi JH, Lee MY. Increased Expression of Slit2 and its Robo Receptors During Astroglial Scar Formation After Transient Focal Cerebral Ischemia in Rats. Neurochem Res 2016; 41:3373-3385. [PMID: 27686659 DOI: 10.1007/s11064-016-2072-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/13/2016] [Accepted: 09/23/2016] [Indexed: 01/30/2023]
Abstract
Slit2, a secreted glycoprotein, has recently been implicated in the post-ischemic astroglial reaction. The objective of this study was to investigate the temporal changes and cellular localization of Slit2 and its receptors, Robo1, Robo2, and Robo4, in a rat transient focal ischemia model induced by middle cerebral artery occlusion. We used double- and triple-immunolabeling to determine the cell-specific changes in Slit2 and its receptors during a 10-week post-ischemia period. The expression profiles of Slit2 and the Robo receptors shared overlapping expression patterns in sham-operated and ischemic striatum. Constitutive expression of Slit2 and Robo receptors was observed in striatal neurons with weak intensity, whereas in rats reperfused after ischemic insults, these immunoreactivities were increased in reactive astrocytes. Astroglial induction of Slit2 and Robo in the peri-infarct region was distinct on days 7-14 after reperfusion and thereafter increased progressively throughout the 10-week experimental period. Slit2 and Robo were prominently expressed in the perinuclear cytoplasm and main processes of reactive astrocytes forming the astroglial scar. This observation was confirmed by quantification of the mean fluorescence intensity of Slit2 and Robo receptors over reactive astrocytes localized at the edge of the infarct area. However, activated microglia/macrophages in the peri-infarct area were devoid of any specific labeling for Slit2 and Robo. Thus, our data revealed a selective and sustained induction of Slit2 and Robo in astrocytes localized throughout the astroglial scar after ischemic stroke, suggesting that Slit2/Robo signaling participates in glial scar formation and brain remodeling following ischemic injury.
Collapse
Affiliation(s)
- Xuyan Jin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, South Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, South Korea
| | - Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, South Korea
| | - Jeong-Heon Choi
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, South Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, South Korea.
| |
Collapse
|
17
|
Park JH, Pak HJ, Riew TR, Shin YJ, Lee MY. Increased expression of Slit2 and its receptors Robo1 and Robo4 in reactive astrocytes of the rat hippocampus after transient forebrain ischemia. Brain Res 2016; 1634:45-56. [PMID: 26764532 DOI: 10.1016/j.brainres.2015.12.056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/26/2015] [Accepted: 12/28/2015] [Indexed: 12/16/2022]
Abstract
Slit2 is a secreted glycoprotein that was originally identified as a chemorepulsive factor in the developing brain; however, it was recently reported that Slit2 is associated with adult neuronal function including a variety of pathophysiological processes. To elucidate whether Slit2 is implicated in the pathophysiology of ischemic injury, we investigated the temporal changes and cellular localization of Slit2 and its predominant receptors, Robo1 and Robo4, for 28 days after transient forebrain ischemia. Slit2 and its receptors had similar overall expression patterns in the control and ischemic hippocampi. The ligand and receptors were constitutively expressed in hippocampal neurons in control animals; however, in animals with ischemic injury, their upregulation was detected in reactive astrocytes, but not in neurons or activated microglia, in the CA1 region. Astroglial induction of Slit2 and its receptors occurred by day 3 after reperfusion, and appeared to increase progressively until the final time point on day 28. Their temporal expression patterns overlapped with the time period in which reactive astrocytes undergo dynamic structural changes and appear hypertrophic in the ischemic hippocampus. The immunohistochemical data were consistent with the results of the immunoblot analyses, indicating that the expression of Slit2 and Robo increased progressively over the relatively long period of 28 days examined here. Collectively, these results suggest that Slit2/Robo signaling may be involved in regulating the astroglial reaction via autocrine or paracrine mechanisms in post-ischemic processes. Moreover, this may contribute to the dynamic morphological changes that occur in astrocytes in response to ischemic injury.
Collapse
Affiliation(s)
- Joo-Hee Park
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Republic of Korea
| | - Ha-Jin Pak
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Republic of Korea
| | - Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Republic of Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Republic of Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Republic of Korea.
| |
Collapse
|
18
|
Jaworski A, Tom I, Tong RK, Gildea HK, Koch AW, Gonzalez LC, Tessier-Lavigne M. Operational redundancy in axon guidance through the multifunctional receptor Robo3 and its ligand NELL2. Science 2015; 350:961-5. [PMID: 26586761 DOI: 10.1126/science.aad2615] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Axon pathfinding is orchestrated by numerous guidance cues, including Slits and their Robo receptors, but it remains unclear how information from multiple cues is integrated or filtered. Robo3, a Robo family member, allows commissural axons to reach and cross the spinal cord midline by antagonizing Robo1/2-mediated repulsion from midline-expressed Slits and potentiating deleted in colorectal cancer (DCC)-mediated midline attraction to Netrin-1, but without binding either Slits or Netrins. We identified a secreted Robo3 ligand, neural epidermal growth factor-like-like 2 (NELL2), which repels mouse commissural axons through Robo3 and helps steer them to the midline. These findings identify NELL2 as an axon guidance cue and establish Robo3 as a multifunctional regulator of pathfinding that simultaneously mediates NELL2 repulsion, inhibits Slit repulsion, and facilitates Netrin attraction to achieve a common guidance purpose.
Collapse
Affiliation(s)
- Alexander Jaworski
- Division of Research, Genentech, South San Francisco, CA 94080, USA. Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA. Department of Neuroscience, Brown University, Providence, RI 02912, USA.
| | - Irene Tom
- Department of Protein Chemistry, Genentech, South San Francisco, CA 94080, USA
| | - Raymond K Tong
- Department of Protein Chemistry, Genentech, South San Francisco, CA 94080, USA
| | - Holly K Gildea
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Alexander W Koch
- Department of Protein Chemistry, Genentech, South San Francisco, CA 94080, USA
| | - Lino C Gonzalez
- Department of Protein Chemistry, Genentech, South San Francisco, CA 94080, USA
| | - Marc Tessier-Lavigne
- Division of Research, Genentech, South San Francisco, CA 94080, USA. Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA.
| |
Collapse
|
19
|
Neuhaus-Follini A, Bashaw GJ. Crossing the embryonic midline: molecular mechanisms regulating axon responsiveness at an intermediate target. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:377-89. [PMID: 25779002 DOI: 10.1002/wdev.185] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/23/2015] [Accepted: 02/05/2015] [Indexed: 11/07/2022]
Abstract
In bilaterally symmetric animals, the precise assembly of neural circuitry at the midline is essential for coordination of the left and right sides of the body. Commissural axons must first be directed across the midline and then be prevented from re-crossing in order to ensure proper midline connectivity. Here, we review the attractants and repellents that direct axonal navigation at the ventral midline and the receptors on commissural neurons through which they signal. In addition, we discuss the mechanisms that commissural axons use to switch their responsiveness to midline-derived cues, so that they are initially responsive to midline attractants and subsequently responsive to midline repellents.
Collapse
Affiliation(s)
- Alexandra Neuhaus-Follini
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Greg J Bashaw
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
20
|
Blacklaws J, Deska-Gauthier D, Jones CT, Petracca YL, Liu M, Zhang H, Fawcett JP, Glover JC, Lanuza GM, Zhang Y. Sim1 is required for the migration and axonal projections of V3 interneurons in the developing mouse spinal cord. Dev Neurobiol 2015; 75:1003-17. [PMID: 25652362 DOI: 10.1002/dneu.22266] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 11/09/2022]
Abstract
V3 spinal interneurons (INs) are a group of excitatory INs that play a crucial role in producing balanced and stable gaits in vertebrate animals. In the developing mouse spinal cord, V3 INs arise from the most ventral progenitor domain and form anatomically distinctive subpopulations in adult spinal cords. They are marked by the expression of transcription factor Sim1 postmitotically, but the function of Sim1 in V3 development remains unknown. Here, we used Sim1(Cre) ;tdTomato mice to trace the fate of V3 INs in a Sim1 mutant versus control genetic background during development. In Sim1 mutants, V3 INs are produced normally and maintain a similar position and organization as in wild types before E12.5. Further temporal analysis revealed that the V3 INs in the mutants failed to migrate properly to form V3 subgroups along the dorsoventral axis of the spinal cord. At birth, in the Sim1 mutant the number of V3 INs in the ventral subgroup was normal, but they were significantly reduced in the dorsal subgroup with a concomitant increase in the intermediate subgroup. Retrograde labeling at lumbar level revealed that loss of Sim1 led to a reduction in extension of contralateral axon projections both at E14.5 and P0 without affecting ipsilateral axon projections. These results demonstrate that Sim1 is essential for proper migration and the guidance of commissural axons of the spinal V3 INs.
Collapse
Affiliation(s)
- Jake Blacklaws
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Dylan Deska-Gauthier
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Christopher T Jones
- Department of Mathematics & Statistics, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Yanina L Petracca
- Developmental Neurobiology Lab, Instituto Leloir and Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET). Av Patricias Argentinas 435, Buenos Aires, 1405, Argentina
| | - Mingwei Liu
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Han Zhang
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - James P Fawcett
- Departments of Pharmacology and Surgery, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Joel C Glover
- Department of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Guillermo M Lanuza
- Developmental Neurobiology Lab, Instituto Leloir and Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET). Av Patricias Argentinas 435, Buenos Aires, 1405, Argentina
| | - Ying Zhang
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| |
Collapse
|
21
|
Zelina P, Blockus H, Zagar Y, Péres A, Friocourt F, Wu Z, Rama N, Fouquet C, Hohenester E, Tessier-Lavigne M, Schweitzer J, Crollius H, Chédotal A. Signaling Switch of the Axon Guidance Receptor Robo3 during Vertebrate Evolution. Neuron 2014; 84:1258-72. [DOI: 10.1016/j.neuron.2014.11.004] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2014] [Indexed: 01/07/2023]
|
22
|
Andermatt I, Wilson NH, Bergmann T, Mauti O, Gesemann M, Sockanathan S, Stoeckli ET. Semaphorin 6B acts as a receptor in post-crossing commissural axon guidance. Development 2014; 141:3709-20. [PMID: 25209245 DOI: 10.1242/dev.112185] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Semaphorins are a large family of axon guidance molecules that are known primarily as ligands for plexins and neuropilins. Although class-6 semaphorins are transmembrane proteins, they have been implicated as ligands in different aspects of neural development, including neural crest cell migration, axon guidance and cerebellar development. However, the specific spatial and temporal expression of semaphorin 6B (Sema6B) in chick commissural neurons suggested a receptor role in axon guidance at the spinal cord midline. Indeed, in the absence of Sema6B, post-crossing commissural axons lacked an instructive signal directing them rostrally along the contralateral floorplate border, resulting in stalling at the exit site or even caudal turns. Truncated Sema6B lacking the intracellular domain was unable to rescue the loss-of-function phenotype, confirming a receptor function of Sema6B. In support of this, we demonstrate that Sema6B binds to floorplate-derived plexin A2 (PlxnA2) for navigation at the midline, whereas a cis-interaction between PlxnA2 and Sema6B on pre-crossing commissural axons may regulate the responsiveness of axons to floorplate-derived cues.
Collapse
Affiliation(s)
- Irwin Andermatt
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Nicole H Wilson
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Timothy Bergmann
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Olivier Mauti
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Matthias Gesemann
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Shanthini Sockanathan
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Esther T Stoeckli
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| |
Collapse
|
23
|
Li L, Liu S, Lei Y, Cheng Y, Yao C, Zhen X. Robo3.1A suppresses slit-mediated repulsion by triggering degradation of Robo2. J Neurosci Res 2014; 92:835-46. [PMID: 24936616 DOI: 10.1002/jnr.23364] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Slits and Robos control the midline crossing of commissural axons, which are not sensitive to the midline repellent Slit before crossing but gain Slit responsiveness to exit the midline and avoid recrossing. Robo3.1A promotes midline crossing of commissural axons by suppressing the axonal responsiveness to the midline repellent Slit, but the underlying mechanism remains unclear. By using a cell surface binding assay and immunoprecipitation, we observed that Robo3.1A did not bind Slit on its own but prevented the specific binding of Slit to the cell surface when it was coexpressed with its close homologue Robo1 or Robo2 (Robo1/2), which are known to mediate the Slit repulsion. Cotransfection with Robo3.1A significantly reduced the protein level of Robo2 in HEK293 cells, and overexpression of Robo3.1A also significantly decreased Robo2 protein level in cerebellar granule cells. Downregulation of endogenous Robo3 by specific small interference RNA (siRNA) significantly increased Robo1 protein level, Slit binding to the cell surface was significantly elevated, and Slit-triggered growth cone collapse appeared after downregulation of Robo3 in cultured cortical neurons. Immunocytochemical staining showed that Robo2 and Robo3 colocalized in intracellular vesicles positive for the marker of late endosomes and lysosomes, but not trans-Golgi apparatus and early endosomes. Thus Robo3.1A may prevent the Slit responsiveness by recruiting Robo1/2 into a late endosome- and lysosome-dependent degradation pathway.
Collapse
|
24
|
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.
Collapse
|
25
|
James G, Foster SR, Key B, Beverdam A. The expression pattern of EVA1C, a novel Slit receptor, is consistent with an axon guidance role in the mouse nervous system. PLoS One 2013; 8:e74115. [PMID: 24040182 PMCID: PMC3767613 DOI: 10.1371/journal.pone.0074115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 08/01/2013] [Indexed: 11/18/2022] Open
Abstract
The Slit/Robo axon guidance families play a vital role in the formation of neural circuitry within select regions of the developing mouse nervous system. Typically Slits signal through the Robo receptors, however they also have Robo-independent functions. The novel Slit receptor Eva-1, recently discovered in C. elegans, and the human orthologue of which is located in the Down syndrome critical region on chromosome 21, could account for some of these Robo independent functions as well as provide selectivity to Robo-mediated axon responses to Slit. Here we investigate the expression of the mammalian orthologue EVA1C in regions of the developing mouse nervous system which have been shown to exhibit Robo-dependent and -independent responses to Slit. We report that EVA1C is expressed by axons contributing to commissures, tracts and nerve pathways of the developing spinal cord and forebrain. Furthermore it is expressed by axons that display both Robo-dependent and -independent functions of Slit, supporting a role for EVA1C in Slit/Robo mediated neural circuit formation in the developing nervous system.
Collapse
Affiliation(s)
- Gregory James
- School of Biomedical Science, University of Queensland, Brisbane, Australia
| | - Simon R. Foster
- School of Biomedical Science, University of Queensland, Brisbane, Australia
| | - Brian Key
- School of Biomedical Science, University of Queensland, Brisbane, Australia
- * E-mail: (BK); (AB)
| | - Annemiek Beverdam
- School of Biomedical Science, University of Queensland, Brisbane, Australia
- * E-mail: (BK); (AB)
| |
Collapse
|
26
|
Wang G, Li Y, Wang XY, Han Z, Chuai M, Wang LJ, Ho Lee KK, Geng JG, Yang X. Slit/Robo1 signaling regulates neural tube development by balancing neuroepithelial cell proliferation and differentiation. Exp Cell Res 2013; 319:1083-93. [PMID: 23438940 DOI: 10.1016/j.yexcr.2013.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 02/05/2013] [Accepted: 02/08/2013] [Indexed: 12/27/2022]
Abstract
Formation of the neural tube is the morphological hallmark for development of the embryonic central nervous system (CNS). Therefore, neural tube development is a crucial step in the neurulation process. Slit/Robo signaling was initially identified as a chemo-repellent that regulated axon growth cone elongation, but its role in controlling neural tube development is currently unknown. To address this issue, we investigated Slit/Robo1 signaling in the development of chick neCollege of Life Sciences Biocentre, University of Dundee, Dundee DD1 5EH, UKural tube and transgenic mice over-expressing Slit2. We disrupted Slit/Robo1 signaling by injecting R5 monoclonal antibodies into HH10 neural tubes to block the Robo1 receptor. This inhibited the normal development of the ventral body curvature and caused the spinal cord to curl up into a S-shape. Next, Slit/Robo1 signaling on one half-side of the chick embryo neural tube was disturbed by electroporation in ovo. We found that the morphology of the neural tube was dramatically abnormal after we interfered with Slit/Robo1 signaling. Furthermore, we established that silencing Robo1 inhibited cell proliferation while over-expressing Robo1 enhanced cell proliferation. We also investigated the effects of altering Slit/Robo1 expression on Sonic Hedgehog (Shh) and Pax7 expression in the developing neural tube. We demonstrated that over-expressing Robo1 down-regulated Shh expression in the ventral neural tube and resulted in the production of fewer HNK-1(+) migrating neural crest cells (NCCs). In addition, Robo1 over-expression enhanced Pax7 expression in the dorsal neural tube and increased the number of Slug(+) pre-migratory NCCs. Conversely, silencing Robo1 expression resulted in an enhanced Shh expression and more HNK-1(+) migrating NCCs but reduced Pax7 expression and fewer Slug(+) pre-migratory NCCs were observed. In conclusion, we propose that Slit/Robo1 signaling is involved in regulating neural tube development by tightly coordinating cell proliferation and differentiation during neurulation.
Collapse
Affiliation(s)
- Guang Wang
- Key Laboratory for Regenerative Medicine of The Ministry of Education, Department of Histology and Embryology, School of Medicine, Jinan University, Guangzhou 510632, China
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Philipp M, Niederkofler V, Debrunner M, Alther T, Kunz B, Stoeckli ET. RabGDI controls axonal midline crossing by regulating Robo1 surface expression. Neural Dev 2012; 7:36. [PMID: 23140504 PMCID: PMC3520763 DOI: 10.1186/1749-8104-7-36] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 10/12/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Axons navigate to their future synaptic targets with the help of choice points, intermediate targets that express axon guidance cues. Once they reach a choice point, axons need to switch their response from attraction to repulsion in order to move on with the next stage of their journey. The mechanisms underlying the change in axonal responsiveness are poorly understood. Commissural axons become sensitive to the repulsive activity of Slits when they cross the ventral midline of the CNS. Responsiveness to Slits depends on surface expression of Robo receptors. In Drosophila, Commissureless (Comm) plays a crucial regulatory role in midline crossing by keeping Robo levels low on precommissural axons. Interestingly, to date no vertebrate homolog of comm has been identified. Robo3/Rig1 has been shown to control Slit sensitivity before the midline, but without affecting Robo1 surface expression. RESULTS We had identified RabGDI, a gene linked to human mental retardation and an essential component of the vesicle fusion machinery, in a screen for differentially expressed floor-plate genes. Downregulation of RabGDI by in ovo RNAi caused commissural axons to stall in the floor plate, phenocopying the effect observed after downregulation of Robo1. Conversely, premature expression of RabGDI prevented commissural axons from entering the floor plate. Furthermore, RabGDI triggered Robo1 surface expression in cultured commissural neurons. Taken together, our results identify RabGDI as a component of the switching mechanism that is required for commissural axons to change their response from attraction to repulsion at the intermediate target. CONCLUSION RabGDI takes over the functional role of fly Comm by regulating the surface expression of Robo1 on commissural axons in vertebrates. This in turn allows commissural axons to switch from attraction to repulsion at the midline of the spinal cord.
Collapse
Affiliation(s)
- Melanie Philipp
- Institute for Biochemistry and Molecular Biology, University of Ulm, Ulm, Germany
| | | | - Marc Debrunner
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich, CH, 8057, Switzerland
| | - Tobias Alther
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich, CH, 8057, Switzerland
| | - Beat Kunz
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich, CH, 8057, Switzerland
| | - Esther T Stoeckli
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich, CH, 8057, Switzerland
| |
Collapse
|
28
|
Cariboni A, Andrews WD, Memi F, Ypsilanti AR, Zelina P, Chedotal A, Parnavelas JG. Slit2 and Robo3 modulate the migration of GnRH-secreting neurons. Development 2012; 139:3326-31. [PMID: 22912413 PMCID: PMC3424043 DOI: 10.1242/dev.079418] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons are born in the nasal placode and migrate along olfactory and vomeronasal axons to reach the forebrain and settle in the hypothalamus, where they control reproduction. The molecular cues that guide their migration have not been fully identified, but are thought to control either cell movement directly or the patterning of their axonal substrates. Using genetically altered mouse models we show that the migration of GnRH neurons is directly modulated by Slit2 and Robo3, members of the axon guidance Slit ligand and Robo receptor families. Mice lacking Slit2 or Robo3 have a reduced number of GnRH neurons in the forebrain, but a normal complement of their supporting axons, pointing to a direct role for these molecules in GnRH neuron migration.
Collapse
Affiliation(s)
- Anna Cariboni
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT UK.
| | | | | | | | | | | | | |
Collapse
|
29
|
Bonner J, Letko M, Nikolaus OB, Krug L, Cooper A, Chadwick B, Conklin P, Lim A, Chien CB, Dorsky RI. Midline crossing is not required for subsequent pathfinding decisions in commissural neurons. Neural Dev 2012; 7:18. [PMID: 22672767 PMCID: PMC3507651 DOI: 10.1186/1749-8104-7-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 05/03/2012] [Indexed: 11/16/2022] Open
Abstract
Background Growth cone navigation across the vertebrate midline is critical in the establishment of nervous system connectivity. While midline crossing is achieved through coordinated signaling of attractive and repulsive cues, this has never been demonstrated at the single cell level. Further, though growth cone responsiveness to guidance cues changes after crossing the midline, it is unclear whether midline crossing itself is required for subsequent guidance decisions in vivo. In the zebrafish, spinal commissures are initially formed by a pioneer neuron called CoPA (Commissural Primary Ascending). Unlike in other vertebrate models, CoPA navigates the midline alone, allowing for single-cell analysis of axon guidance mechanisms. Results We provide evidence that CoPA expresses the known axon guidance receptors dcc, robo3 and robo2. Using loss of function mutants and gene knockdown, we show that the functions of these genes are evolutionarily conserved in teleosts and that they are used consecutively by CoPA neurons. We also reveal novel roles for robo2 and robo3 in maintaining commissure structure. When midline crossing is prevented in robo3 mutants and dcc gene knockdown, ipsilaterally projecting neurons respond to postcrossing guidance cues. Furthermore, DCC inhibits Robo2 function before midline crossing to allow a midline approach and crossing. Conclusions Our results demonstrate that midline crossing is not required for subsequent guidance decisions by pioneer axons and that this is due, in part, to DCC inhibition of Robo2 function prior to midline crossing.
Collapse
Affiliation(s)
- Jennifer Bonner
- Biology Department, Skidmore College, Saratoga Springs, NY 12866, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Zheng W, Geng AQ, Li PF, Wang Y, Yuan XB. Robo4 regulates the radial migration of newborn neurons in developing neocortex. ACTA ACUST UNITED AC 2011; 22:2587-601. [PMID: 22123939 DOI: 10.1093/cercor/bhr330] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During the morphogenesis of neocortex, newborn neurons undergo radial migration from the ventricular zone toward the surface of the cortical plate to form an "inside-out" lamina structure. The spatiotemporal signals that control this stereotyped radial migration remain elusive. Here, we report that a recently identified Robo family member Robo4 (Magic Roundabout), which was considered to be solely expressed in endothelial cells, is expressed in developing brain and regulates the radial migration of newborn neurons in neocortex. Downregulation of Robo4 expression in cortical newborn neurons by using in utero electroporation, with either specific siRNAs in wild-type rodents or with Cre recombinase in floxed-robo4 mutant mice, led to severe defects in the radial migration of newborn neurons with misorientation of these neurons. Moreover, newborn neurons transfected with Robo4 siRNAs exhibited significantly lower motility in a transwell migration assay (Boyden chamber) in the absence of Slit and significantly higher sensitivity to the repulsive effect of Slit in both transwell migration assay and growth cone collapse assay. Overall, our results showed an important role of Robo4 in the regulation of cortical radial migration through Slit-dependent and -independent mechanisms.
Collapse
Affiliation(s)
- Wang Zheng
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | | | | | | | | |
Collapse
|
31
|
Nawabi H, Castellani V. Axonal commissures in the central nervous system: how to cross the midline? Cell Mol Life Sci 2011; 68:2539-53. [PMID: 21538161 PMCID: PMC11114790 DOI: 10.1007/s00018-011-0691-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/08/2011] [Accepted: 04/14/2011] [Indexed: 01/02/2023]
Abstract
Organisms with bilateral symmetry elaborate patterns of neuronal projections connecting both sides of the central nervous system at all levels of the neuraxis. During development, these so-called commissural projections navigate across the midline to innervate their contralateral targets. Commissural axon pathfinding has been extensively studied over the past years and turns out to be a highly complex process, implicating modulation of axon responsiveness to the various guidance cues that instruct axon trajectories towards, within and away from the midline. Understanding the molecular mechanisms allowing these switches of response to take place at the appropriate time and place is a major challenge for current research. Recent work characterized several instructive processes controlling the spatial and temporal fine-tuning of the guidance molecular machinery. These findings illustrate the molecular strategies by which commissural axons modulate their sensitivity to guidance cues during midline crossing and show that regulation at both transcriptional and post-transcriptional levels are crucial for commissural axon guidance.
Collapse
Affiliation(s)
- Homaira Nawabi
- F.M. Kirby Neurobiology Center, Children's Hospital and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
| | | |
Collapse
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
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.
Collapse
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
| |
Collapse
|
34
|
Reeber SL, Kaprielian Z. Leaving the midline: how Robo receptors regulate the guidance of post-crossing spinal commissural axons. Cell Adh Migr 2009; 3:300-4. [PMID: 19556886 DOI: 10.4161/cam.3.3.9156] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In the developing nervous system, pathfinding axons navigate through a series of intermediate targets in order to form synaptic connections. Vertebrate spinal commissural axons extend toward and across the floor plate (FP), a key intermediate target located at the ventral midline (VM). Subsequently, post-crossing commissural axons grow either alongside or significant distances away from the floor plate (FP), but never re-cross the VM. Consistent with this behavior, post-crossing commissural axons lose responsiveness to the FP-associated chemoattractants, Netrin-1 and SHH, and gain responsiveness to Slits, which are potent midline repellents, in vitro. In addition, the results of several in vivo studies suggest that the upregulation of Slit-binding repulsive Robo receptors, Robo1/2, alters the responsiveness of decussated commissural axons to midline guidance cues. Nevertheless, in vertebrates, it is unclear whether Robo1/2 are the sole or major repellent receptors responsible for driving these commissural axons away from the VM and preventing their re-entry into the FP. We recently re-visited these issues in the chick spinal cord by assessing the consequences of manipulating Robo expression on commissural axons in ovo. Our findings suggest that, at least in chick embryos, the upregulation of repulsive Robos on post-crossing axons alters the responsiveness of these axons to midline repellents and facilitates their expulsion from, but is not likely to have a significant role in preventing their re-entry into the VM.
Collapse
Affiliation(s)
- Stacey L Reeber
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | | |
Collapse
|
35
|
Burgess HA, Johnson SL, Granato M. Unidirectional startle responses and disrupted left-right co-ordination of motor behaviors in robo3 mutant zebrafish. GENES BRAIN AND BEHAVIOR 2009; 8:500-11. [PMID: 19496826 DOI: 10.1111/j.1601-183x.2009.00499.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Roundabout (Robo) family of receptors and their Slit ligands play well-established roles in axonal guidance, including in humans where horizontal gaze palsy with progressive scoliosis (HGPPS) is caused by mutations in the robo3 gene. Although significant progress has been made toward understanding the mechanism by which Robo receptors establish commissural projections in the central nervous system, less is known about how these projections contribute to neural circuits mediating behavior. In this study, we report cloning of the zebrafish behavioral mutant twitch twice and show that twitch twice encodes robo3. We show that in mutant hindbrains the axons of an identified pair of neurons, the Mauthner cells, fail to cross the midline. The Mauthner neurons are essential for the startle response, and in twitch twice/robo3 mutants misguidance of the Mauthner axons results in a unidirectional startle response. Moreover, we show that twitch twice mutants exhibit normal visual acuity but display defects in horizontal eye movements, suggesting a specific and critical role for twitch twice/robo3 in sensory-guided behavior.
Collapse
Affiliation(s)
- H A Burgess
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA
| | | | | |
Collapse
|
36
|
Barber M, Di Meglio T, Andrews WD, Hernández-Miranda LR, Murakami F, Chédotal A, Parnavelas JG. The role of Robo3 in the development of cortical interneurons. ACTA ACUST UNITED AC 2009; 19 Suppl 1:i22-31. [PMID: 19366869 PMCID: PMC2693537 DOI: 10.1093/cercor/bhp041] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A number of studies in recent years have shown that members of the Roundabout (Robo) receptor family, Robo1 and Robo2, play significant roles in the formation of axonal tracks in the developing forebrain and in the migration and morphological differentiation of cortical interneurons. Here, we investigated the expression and function of Robo3 in the developing cortex. We found that this receptor is strongly expressed in the preplate layer and cortical hem of the early cortex where it colocalizes with markers of Cajal–Retzius cells and interneurons. Analysis of Robo3 mutant mice at early (embryonic day [E] 13.5) and late (E18.5) stages of corticogenesis revealed no significant change in the number of interneurons, but a change in their morphology at E13.5. However, preliminary analysis on a small number of mice that lacked all 3 Robo receptors indicated a marked reduction in the number of cortical interneurons, but only a limited effect on their morphology. These observations and the results of other recent studies suggest a complex interplay between the 3 Robo receptors in regulating the number, migration and morphological differentiation of cortical interneurons.
Collapse
Affiliation(s)
- Melissa Barber
- Department of Cell and Developmental Biology, University College London, London, UK
| | | | | | | | | | | | | |
Collapse
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Anitha A, Nakamura K, Yamada K, Suda S, Thanseem I, Tsujii M, Iwayama Y, Hattori E, Toyota T, Miyachi T, Iwata Y, Suzuki K, Matsuzaki H, Kawai M, Sekine Y, Tsuchiya K, Sugihara GI, Ouchi Y, Sugiyama T, Koizumi K, Higashida H, Takei N, Yoshikawa T, Mori N. Genetic analyses of roundabout (ROBO) axon guidance receptors in autism. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:1019-27. [PMID: 18270976 DOI: 10.1002/ajmg.b.30697] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Autism is a pervasive developmental disorder diagnosed in early childhood. Abnormalities of serotonergic neurotransmission have been reported in autism. Serotonin transporter (SERT) modulates serotonin levels, and is a major therapeutic target in autism. Factors that regulate SERT expression might be implicated in the pathophysiology of autism. One candidate SERT regulatory protein is the roundabout axon guidance molecule, ROBO. SerT expression in Drosophila is regulated by robo; it plays a vital role in mammalian neurodevelopment also. Here, we examined the associations of ROBO3 and ROBO4 with autism, in a trio association study using DNA from 252 families recruited to AGRE. Four SNPs of ROBO3 (rs3923890, P = 0.023; rs7925879, P = 0.017; rs4606490, P = 0.033; and rs3802905, P = 0.049) and a single SNP of ROBO4 (rs6590109, P = 0.009) showed associations with autism; the A/A genotype of rs3923890 showed lower ADI-R_A scores, which reflect social interaction. Significant haplotype associations were also observed for ROBO3 and ROBO4. We further compared the mRNA expressions of ROBO1, ROBO2, ROBO3, and ROBO4 in the lymphocytes of 19 drug-naïve autistic patients and 20 age- and sex-matched controls. Expressions of ROBO1 (P = 0.018) and ROBO2 (P = 0.023) were significantly reduced in the autistic group; the possibility of using the altered expressions of ROBO as peripheral markers for autism, may be explored. In conclusion, we suggest a possible role of ROBO in the pathogenesis of autism. Abnormalities of ROBO may lead to autism either by interfering with serotonergic system, or by disrupting neurodevelopment. To the best of our knowledge, this is the first report relating ROBO with autism.
Collapse
Affiliation(s)
- A Anitha
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Reeber SL, Sakai N, Nakada Y, Dumas J, Dobrenis K, Johnson JE, Kaprielian Z. Manipulating Robo expression in vivo perturbs commissural axon pathfinding in the chick spinal cord. J Neurosci 2008; 28:8698-708. [PMID: 18753371 PMCID: PMC2886497 DOI: 10.1523/jneurosci.1479-08.2008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 07/12/2008] [Accepted: 07/15/2008] [Indexed: 11/21/2022] Open
Abstract
In vertebrate embryos, most spinal commissural axons cross the ventral midline (VM) and project either alongside or significant distances away from the floor plate (FP). The upregulation of repulsive Robo1/2 receptors on postcrossing commissural axons, in mammals, presumably allows these axons to respond to the midline-associated repellents, Slit1-3, facilitating their expulsion from, and prohibiting their reentry into, the FP. Compelling data suggest that Robo3 represses Robo1/2 function on precrossing axons and that Robo1/2 inhibit attractive guidance receptors on postcrossing axons, thereby ensuring that decussated axons are selectively responsive to midline Slits. However, whether Robo1/2 expel decussated commissural axons from the VM and/or prevent their reentry into the FP has not been explicitly established in vivo. Furthermore, some commissural axons do not require Robo1/2 to elaborate appropriate contralateral projections in the mouse spinal cord. Here, we use unilateral in ovo electroporation together with Atoh1 and Neurog1 enhancer elements to visualize, and assess the consequences of manipulating Robo expression on, dl1 and dl2 chick commissural axons. In response to misexpressing a cytoplasmic truncation of Robo1 and/or Robo2, which should block all Robo-ligand interactions, postcrossing commissural axons extend alongside, but do not project away from or reenter the FP. In contrast, misexpression of full-length Robo2 prevents many commissural axons from crossing the VM. Together, these findings support key and selective in vivo roles for Robo receptors in presumably altering the responsiveness of decussated commissural axons and facilitating their expulsion from the VM within the chick spinal cord.
Collapse
Affiliation(s)
| | - Nozomi Sakai
- Dominick P. Purpura Department of Neuroscience and
| | - Yuji Nakada
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Judy Dumas
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | | | - Jane E. Johnson
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Zaven Kaprielian
- Dominick P. Purpura Department of Neuroscience and
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, and
| |
Collapse
|
40
|
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.
Collapse
Affiliation(s)
- Sonja Mertsch
- Institute of Neuropathology, University Hospital Münster, Domagkstr. 19, 48149, Münster, Germany
| | | | | | | | | | | |
Collapse
|
41
|
Miranda DM, Wigg K, Feng Y, Sandor P, Barr CL. Association study between Gilles de la Tourette Syndrome and two genes in the Robo-Slit pathway located in the chromosome 11q24 linked/associated region. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:68-72. [PMID: 17671968 DOI: 10.1002/ajmg.b.30580] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Gilles de la Tourette Syndrome (GTS) is an inherited neuropsychiatric disorder characterized by the presence of motor and phonic tics. Previous genetic studies have identified linkage and association between GTS and the 11q24 chromosomal region. We selected for study, within this region, two possible susceptibility genes for GTS, the ROBO3 and ROBO4 genes. These two genes were selected because of the recent identification of SLITRK1 as a potential susceptibility gene for GTS based on a translocation breakpoint and the further finding of two mutations in the SLITRK1 gene in three patients with GTS. While thus far, the SLITRK1 gene appears to account for only a few cases of GTS, these findings, if confirmed, point to other genes in these pathways that may contribute to GTS. Based on this, we examined two genes in the Slit-Robo pathway involved in cell migration, axonal pathfinding, and/or neuronal differentiation because of their location in 11q24, a region previously identified as linked and associated with GTS. We selected six haplotype tagging single nucleotide polymorphisms (SNPs) for ROBO3 and four for ROBO4 and genotyped them in our sample of trios and sibpair families diagnosed with GTS. Based on 155 nuclear families with 255 affected children, we did not find evidence for association between GTS and either the ROBO3 or ROBO4 genes. Thus, these two genes are unlikely to be the susceptibility genes contributing to GTS on 11q24.
Collapse
Affiliation(s)
- D M Miranda
- Department of Pharmacology of Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | | | | | | |
Collapse
|
42
|
Abstract
Interneurons are an integral part of cortical neuronal circuits. During the past decade, numerous studies have shown that these cells, unlike their pyramidal counterparts that are derived from the neuroepithelium along the lumen of the lateral ventricles, are generated in the ganglionic eminences in the subpallium. They use tangential migratory paths to reach the cortex, guided by intrinsic and extrinsic cues. Evidence is now emerging which suggests that the family of Slit proteins, acting through Robo receptors, play a role not only in axon guidance in the developing forebrain, but also as guiding signals in the migration of cortical interneurons. Here we describe the patterns of expression of Slit and Robo at different stages of forebrain development and review the evidence in support of their role in cortical interneuron migration. Slit-Robo signal transduction mechanisms are also important during normal development in a number of systems in the body and in disease states, making them potential therapeutic targets for the treatment of neurological disorders and certain types of cancer.
Collapse
Affiliation(s)
- William D Andrews
- Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, UK
| | | | | |
Collapse
|
43
|
Rohde LA, Heisenberg CP. Zebrafish Gastrulation: Cell Movements, Signals, and Mechanisms. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 261:159-92. [PMID: 17560282 DOI: 10.1016/s0074-7696(07)61004-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gastrulation is a morphogenetic process that results in the formation of the embryonic germ layers. Here we detail the major cell movements that occur during zebrafish gastrulation: epiboly, internalization, and convergent extension. Although gastrulation is known to be regulated by signaling pathways such as the Wnt/planar cell polarity pathway, many questions remain about the underlying molecular and cellular mechanisms. Key factors that may play a role in gastrulation cell movements are cell adhesion and cytoskeletal rearrangement. In addition, some of the driving force for gastrulation may derive from tissue interactions such as those described between the enveloping layer and the yolk syncytial layer. Future exploration of gastrulation mechanisms relies on the development of sensitive and quantitative techniques to characterize embryonic germ-layer properties.
Collapse
Affiliation(s)
- Laurel A Rohde
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | |
Collapse
|
44
|
Kadison SR, Murakami F, Matise MP, Kaprielian Z. The role of floor plate contact in the elaboration of contralateral commissural projections within the embryonic mouse spinal cord. Dev Biol 2006; 296:499-513. [PMID: 16854408 DOI: 10.1016/j.ydbio.2006.06.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 06/13/2006] [Accepted: 06/13/2006] [Indexed: 10/24/2022]
Abstract
In vertebrate embryos, commissural axons extend toward and across the floor plate (FP), an intermediate target at the ventral midline (VM) of the spinal cord. After decussating, many commissural axons turn into the longitudinal plane and elaborate diverse projections. FP contact is thought to alter the responsiveness of these axons so that they can exit the FP and adopt new trajectories. However, a requirement for the FP in shaping contralateral commissural projections has not been established in higher vertebrates. Here we further analyze to what extent FP contact is necessary for the elaboration of decussated commissural projections both in cultured, FP-excised spinal cord preparations and in gli2-deficient mice, which lack a FP. In FP-lacking spinal cords, we observe a large number of appropriately projecting contralateral commissural projections in vivo and in vitro. Surprisingly, even though gli2 mutants lack a FP, slit1-3 mRNA and their receptors (Robo1/2) are expressed in a wild-type-like manner. In addition, blocking Robo-Slit interactions in FP-lacking spinal cord explants prevents commissural axons from leaving the VM and turning longitudinally. Thus, compared to FP contact, Slit-Robo interactions are more critical for driving commissural axons out of the VM and facilitating the elaboration of a subset of contralateral commissural projections.
Collapse
Affiliation(s)
- Stephanie R Kadison
- Department of Pathology and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Kennedy Center Rm. 624, 1410 Pelham Parkway South, Bronx, NY 10461, USA.
| | | | | | | |
Collapse
|
45
|
Challa AK, McWhorter ML, Wang C, Seeger MA, Beattie CE. Robo3 isoforms have distinct roles during zebrafish development. Mech Dev 2006; 122:1073-86. [PMID: 16129585 DOI: 10.1016/j.mod.2005.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 06/17/2005] [Indexed: 11/16/2022]
Abstract
Roundabout (Robo) receptors and their secreted ligand Slits have been shown to function in a number of developmental events both inside and outside of the nervous system. We previously cloned zebrafish robo orthologs to gain a better understanding of Robo function in vertebrates. Further characterization of one of these orthologs, robo3, has unveiled the presence of two distinct isoforms, robo3 variant 1 (robo3var1) and robo3 variant 2 (robo3var2). These two isoforms differ only in their 5'-ends with robo3var1, but not robo3var2, containing a canonical signal sequence. Despite this difference, both forms accumulate on the cell surface. Both isoforms are contributed maternally and exhibit unique and dynamic gene expression patterns during development. Functional analysis of robo3 isoforms using an antisense gene knockdown strategy suggests that Robo3var1 functions in motor axon pathfinding, whereas Robo3var2 appears to function in dorsoventral cell fate specification. This study reveals a novel function for Robo receptors in specifying ventral cell fates during vertebrate development.
Collapse
Affiliation(s)
- Anil K Challa
- Center for Molecular Neurobiology, Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | | | | | | | | |
Collapse
|
46
|
Abstract
Commissural axons grow along complex pathways toward, across, and beyond the midline of the central nervous system. Taking commissural axons in the vertebrate spinal cord and the Drosophila ventral nerve cord as examples, we examine how commissural axon pathfinding is regulated by the Slit family of guidance cues and their Robo family receptors. We extract several principles that seem likely to apply to other axons and other contexts, such as the reiterative use of the same guidance molecules in distinct pathfinding decisions, the transcriptional specification of a pathway, the posttranscriptional regulation of growth along the pathway, and the possible role of feedback mechanisms to ensure the fidelity of pathfinding choices. Such mechanisms may help explain how a relatively small number of guidance molecules can generate complex and stereotyped wiring patterns. We also highlight the many gaps in our understanding of commissural axon pathfinding and question some widely accepted views. We hope that this review encourages further efforts to tackle these questions, in the expectation that this system will continue to reveal the general principles of axon pathfinding.
Collapse
Affiliation(s)
- Barry J Dickson
- Research Institute of Molecular Pathology (IMP), A-1030 Vienna, Austria.
| | | |
Collapse
|
47
|
Camurri L, Mambetisaeva E, Davies D, Parnavelas J, Sundaresan V, Andrews W. Evidence for the existence of two Robo3 isoforms with divergent biochemical properties. Mol Cell Neurosci 2005; 30:485-93. [PMID: 16226035 DOI: 10.1016/j.mcn.2005.07.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Revised: 07/22/2005] [Accepted: 07/25/2005] [Indexed: 11/18/2022] Open
Abstract
Robo3 is a member of the roundabout (Robo) family of proteins that plays a key role in axon guidance and cell migration in the developing nervous system. Recent studies have shown that Robo3 plays a crucial role in controlling axon guidance at the midline of the CNS. Here we describe and compare two human Robo3 isoforms, Robo3A and Robo3B, which differ by the insertion of 26 amino acids at the N-terminus, and these forms appear to be evolutionary conserved. We investigated the bioactivity of these isoforms and show that they have different binding properties to Slit, and that orthologs of these forms are expressed in the mouse embryo. In addition, we show that, like other members of the Robo family, Robo3 can bind homophilically, but it is also capable of binding heterophilically to Robo1 and NCAM. We propose that these properties of Robo3 may contribute to its function at the midline of the CNS.
Collapse
Affiliation(s)
- Laura Camurri
- MRC Centre for Developmental Neurobiology, New Hunt's House, King's College, London, Guy's Campus, London SE1 1UL, UK
| | | | | | | | | | | |
Collapse
|