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Gauberg J, Moreno KB, Jayaraman K, Abumeri S, Jenkins S, Salazar AM, Meharena HS, Glasgow SM. Spinal motor neuron development and metabolism are transcriptionally regulated by Nuclear Factor IA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.26.600888. [PMID: 38979382 PMCID: PMC11230388 DOI: 10.1101/2024.06.26.600888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Neural circuits governing all motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
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Curran BM, Nickerson KR, Yung AR, Goodrich LV, Jaworski A, Tessier-Lavigne M, Ma L. Multiple Guidance Mechanisms Control Axon Growth to Generate Precise T-shaped Bifurcation during Dorsal Funiculus Development in the Spinal Cord. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.17.567638. [PMID: 38014092 PMCID: PMC10680847 DOI: 10.1101/2023.11.17.567638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The dorsal funiculus in the spinal cord relays somatosensory information to the brain. It is made of T-shaped bifurcation of dorsal root ganglion (DRG) sensory axons. Our previous study has shown that Slit signaling is required for proper guidance during bifurcation, but loss of Slit does not affect all DRG axons. Here, we examined the role of the extracellular molecule Netrin-1 (Ntn1). Using wholemount staining with tissue clearing, we showed that mice lacking Ntn1 have axons escaping from the dorsal funiculus at the time of bifurcation. Genetic labeling confirmed that these misprojecting axons come from DRG neurons. Single axon analysis showed that loss of Ntn1 does not affect bifurcation but rather alters turning angles. To distinguish their guidance functions, we examined mice with triple deletion of Ntn1, Slit1, and Slit2 and found a completely disorganized dorsal funiculus. Comparing mice with different genotypes using immunolabeling and single axon tracing revealed additive guidance errors, demonstrating the independent roles of Ntn1 and Slit. Moreover, the same defects were observed in embryos lacking their cognate receptors. These in vivo studies thus demonstrate the presence of multi-factorial guidance mechanisms that ensure proper formation of a common branched axonal structure during spinal cord development.
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Affiliation(s)
- Bridget M Curran
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
| | - Kelsey R Nickerson
- Department of Neuroscience, Brown University, Providence, RI 02912
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, RI 02912
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912
| | | | - Le Ma
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
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Abushalbaq O, Baek J, Yaron A, Tran TS. Balancing act of small GTPases downstream of plexin-A4 signaling motifs promotes dendrite elaboration in mammalian cortical neurons. Sci Signal 2024; 17:eadh7673. [PMID: 38227686 DOI: 10.1126/scisignal.adh7673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 12/21/2023] [Indexed: 01/18/2024]
Abstract
The precise development of neuronal morphologies is crucial to the establishment of synaptic circuits and, ultimately, proper brain function. Signaling by the axon guidance cue semaphorin 3A (Sema3A) and its receptor complex of neuropilin-1 and plexin-A4 has multifunctional outcomes in neuronal morphogenesis. Downstream activation of the RhoGEF FARP2 through interaction with the lysine-arginine-lysine motif of plexin-A4 and consequent activation of the small GTPase Rac1 promotes dendrite arborization, but this pathway is dispensable for axon repulsion. Here, we investigated the interplay of small GTPase signaling mechanisms underlying Sema3A-mediated dendritic elaboration in mouse layer V cortical neurons in vitro and in vivo. Sema3A promoted the binding of the small GTPase Rnd1 to the amino acid motif lysine-valine-serine (LVS) in the cytoplasmic domain of plexin-A4. Rnd1 inhibited the activity of the small GTPase RhoA and the kinase ROCK, thus supporting the activity of the GTPase Rac1, which permitted the growth and branching of dendrites. Overexpression of a dominant-negative RhoA, a constitutively active Rac1, or the pharmacological inhibition of ROCK activity rescued defects in dendritic elaboration in neurons expressing a plexin-A4 mutant lacking the LVS motif. Our findings provide insights into the previously unappreciated balancing act between Rho and Rac signaling downstream of specific motifs in plexin-A4 to mediate Sema3A-dependent dendritic elaboration in mammalian cortical neuron development.
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Affiliation(s)
- Oday Abushalbaq
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Jiyeon Baek
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Avraham Yaron
- Department of Biomolecular Sciences and Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tracy S Tran
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA
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Gu Z, Matsuura K, Letelier A, Basista M, Craig C, Imai F, Yoshida Y. Axon Fasciculation, Mediated by Transmembrane Semaphorins, Is Critical for the Establishment of Segmental Specificity of Corticospinal Circuits. J Neurosci 2023; 43:5753-5768. [PMID: 37344234 PMCID: PMC10423052 DOI: 10.1523/jneurosci.0073-22.2023] [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: 01/08/2022] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 06/23/2023] Open
Abstract
Axon fasciculation is thought to be a critical step in neural circuit formation and function. Recent studies have revealed various molecular mechanisms that underlie axon fasciculation; however, the impacts of axon fasciculation, and its corollary, defasciculation, on neural circuit wiring remain unclear. Corticospinal (CS) neurons in the sensorimotor cortex project axons to the spinal cord to control skilled movements. In rodents, the axons remain tightly fasciculated in the brain and traverse the dorsal funiculus of the spinal cord. Here we show that plexinA1 (PlexA1) and plexinA3 (PlexA3) receptors are expressed by CS neurons, whereas their ligands, semaphorin-5A (Sema5A) and semaphorin-5B (Sema5B) are expressed in the medulla at the decussation site of CS axons to inhibit premature defasciculation of these axons. In the absence of Sema5A/5B-PlexA1/A3 signaling, some CS axons are prematurely defasciculated in the medulla of the brainstem, and those defasciculated CS axons aberrantly transverse in the spinal gray matter instead of the spinal dorsal funiculus. In the absence of Sema5A/Sema5B-PlexA1/A3 signaling, CS axons, which would normally innervate the lumbar spinal cord, are unbundled in the spinal gray matter, and prematurely innervate the cervical gray matter with reduced innervation of the lumbar gray matter. In both Sema5A/5B and PlexA1/A3 mutant mice (both sexes), stimulation of the hindlimb motor cortex aberrantly evokes robust forelimb muscle activation. Finally, Sema5A/5B and PlexA1/A3 mutant mice show deficits in skilled movements. These results suggest that proper fasciculation of CS axons is required for appropriate neural circuit wiring and ultimately affect the ability to perform skilled movements.SIGNIFICANCE STATEMENT Axon fasciculation is believed to be essential for neural circuit formation and function. However, whether and how defects in axon fasciculation affect the formation and function of neural circuits remain unclear. Here we examine whether the transmembrane proteins semaphorin-5A (Sema5A) and semaphorin-5B (Sema5B), and their receptors, plexinA1 (PlexA1) and plexinA3 (PlexA3) play roles in the development of corticospinal circuits. We find that Sema5A/Sema5B and PlexA1/A3 are required for proper axon fasciculation of corticospinal neurons. Furthermore, Sema5A/5B and PlexA1/A3 mutant mice show marked deficits in skilled motor behaviors. Therefore, these results strongly suggest that proper corticospinal axon fasciculation is required for the appropriate formation and functioning of corticospinal circuits in mice.
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Affiliation(s)
- Zirong Gu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Ken Matsuura
- Neural Circuit Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | | | - Mark Basista
- Burke Neurological Institute, White Plains, New York 10605
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065
| | - Corey Craig
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Fumiyasu Imai
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
- Burke Neurological Institute, White Plains, New York 10605
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065
| | - Yutaka Yoshida
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
- Burke Neurological Institute, White Plains, New York 10605
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065
- Neural Circuit Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
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Walker LJ, Guevara C, Kawakami K, Granato M. Target-selective vertebrate motor axon regeneration depends on interaction with glial cells at a peripheral nerve plexus. PLoS Biol 2023; 21:e3002223. [PMID: 37590333 PMCID: PMC10464982 DOI: 10.1371/journal.pbio.3002223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 08/29/2023] [Accepted: 06/28/2023] [Indexed: 08/19/2023] Open
Abstract
A critical step for functional recovery from peripheral nerve injury is for regenerating axons to connect with their pre-injury targets. Reestablishing pre-injury target specificity is particularly challenging for limb-innervating axons as they encounter a plexus, a network where peripheral nerves converge, axons from different nerves intermingle, and then re-sort into target-specific bundles. Here, we examine this process at a plexus located at the base of the zebrafish pectoral fin, equivalent to tetrapod forelimbs. Using live cell imaging and sparse axon labeling, we find that regenerating motor axons from 3 nerves coalesce into the plexus. There, they intermingle and sort into distinct branches, and then navigate to their original muscle domains with high fidelity that restores functionality. We demonstrate that this regeneration process includes selective retraction of mistargeted axons, suggesting active correction mechanisms. Moreover, we find that Schwann cells are enriched and associate with axons at the plexus, and that Schwann cell ablation during regeneration causes profound axonal mistargeting. Our data provide the first real-time account of regenerating vertebrate motor axons navigating a nerve plexus and reveal a previously unappreciated role for Schwann cells to promote axon sorting at a plexus during regeneration.
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Affiliation(s)
- Lauren J. Walker
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Camilo Guevara
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, and Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Nickerson KR, Tom I, Cortés E, Abolafia JR, Özkan E, Gonzalez LC, Jaworski A. WFIKKN2 is a bifunctional axon guidance cue that signals through divergent DCC family receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.544950. [PMID: 37398498 PMCID: PMC10312737 DOI: 10.1101/2023.06.15.544950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Axon pathfinding is controlled by attractive and repulsive molecular cues that activate receptors on the axonal growth cone, but the full repertoire of axon guidance molecules remains unknown. The vertebrate DCC receptor family contains the two closely related members DCC and Neogenin with prominent roles in axon guidance and three additional, divergent members - Punc, Nope, and Protogenin - for which functions in neural circuit formation have remained elusive. We identified a secreted Punc/Nope/Protogenin ligand, WFIKKN2, which guides mouse peripheral sensory axons through Nope-mediated repulsion. In contrast, WFIKKN2 attracts motor axons, but not via Nope. These findings identify WFIKKN2 as a bifunctional axon guidance cue that acts through divergent DCC family members, revealing a remarkable diversity of ligand interactions for this receptor family in nervous system wiring. One-Sentence Summary WFIKKN2 is a ligand for the DCC family receptors Punc, Nope, and Prtg that repels sensory axons and attracts motor axons.
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7
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Walker LJ, Guevara C, Kawakami K, Granato M. A glia cell dependent mechanism at a peripheral nerve plexus critical for target-selective axon regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522786. [PMID: 36712008 PMCID: PMC9881934 DOI: 10.1101/2023.01.05.522786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A critical step for functional recovery from peripheral nerve injury is for regenerating axons to connect with their pre-injury targets. Reestablishing pre-injury target specificity is particularly challenging for limb-innervating axons as they encounter a plexus, a network where peripheral nerves converge, axons from different nerves intermingle, and then re-sort into target-specific bundles. Here, we examine this process at a plexus located at the base of the zebrafish pectoral fin, equivalent to tetrapod forelimbs. Using live cell imaging and sparse axon labeling, we find that regenerating motor axons from three nerves coalesce into the plexus. There, they intermingle and sort into distinct branches, and then navigate to their original muscle domains with high fidelity that restores functionality. We demonstrate that this regeneration process includes selective retraction of mistargeted axons, suggesting active correction mechanisms. Moreover, we find that Schwann cells are enriched and associate with axons at the plexus, and that Schwann cell ablation during regeneration causes profound axonal mistargeting. Our data provide the first real time account of regenerating vertebrate motor axons navigating a nerve plexus and reveal a previously unappreciated role for Schwann cells to promote axon sorting at a plexus during regeneration.
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Affiliation(s)
- Lauren J Walker
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Camilo Guevara
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, and Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Single-cell transcriptomic analysis reveals diversity within mammalian spinal motor neurons. Nat Commun 2023; 14:46. [PMID: 36596814 PMCID: PMC9810664 DOI: 10.1038/s41467-022-35574-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Spinal motor neurons (MNs) integrate sensory stimuli and brain commands to generate movements. In vertebrates, the molecular identities of the cardinal MN types such as those innervating limb versus trunk muscles are well elucidated. Yet the identities of finer subtypes within these cell populations that innervate individual muscle groups remain enigmatic. Here we investigate heterogeneity in mouse MNs using single-cell transcriptomics. Among limb-innervating MNs, we reveal a diverse neuropeptide code for delineating putative motor pool identities. Additionally, we uncover that axial MNs are subdivided into three molecularly distinct subtypes, defined by mediolaterally-biased Satb2, Nr2f2 or Bcl11b expression patterns with different axon guidance signatures. These three subtypes are present in chicken and human embryos, suggesting a conserved axial MN expression pattern across higher vertebrates. Overall, our study provides a molecular resource of spinal MN types and paves the way towards deciphering how neuronal subtypes evolved to accommodate vertebrate motor behaviors.
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9
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Dumoulin A, Stoeckli ET. Looking for Guidance - Models and Methods to Study Axonal Navigation. Neuroscience 2023; 508:30-39. [PMID: 35940454 DOI: 10.1016/j.neuroscience.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 01/17/2023]
Abstract
The molecular mechanisms of neural circuit formation have been of interest to Santiago Ramón y Cajal and thousands of neuroscientists sharing his passion for neural circuits ever since. Cajal was a brilliant observer and taught us about the connections and the morphology of neurons in the adult and developing nervous system. Clearly, we will not learn about molecular mechanisms by just looking at brain sections or cells in culture. Technically, we had to come a long way to today's possibilities that allow us to perturb target gene expression and watch the consequences of our manipulations on navigating axons in situ. In this review, we summarize landmark steps towards modern live-imaging approaches used to study the molecular basis of axon guidance.
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Affiliation(s)
- Alexandre Dumoulin
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Esther T Stoeckli
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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Vieira JR, Shah B, Dupraz S, Paredes I, Himmels P, Schermann G, Adler H, Motta A, Gärtner L, Navarro-Aragall A, Ioannou E, Dyukova E, Bonnavion R, Fischer A, Bonanomi D, Bradke F, Ruhrberg C, Ruiz de Almodóvar C. Endothelial PlexinD1 signaling instructs spinal cord vascularization and motor neuron development. Neuron 2022; 110:4074-4089.e6. [PMID: 36549270 PMCID: PMC9796814 DOI: 10.1016/j.neuron.2022.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 11/04/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022]
Abstract
How the vascular and neural compartment cooperate to achieve such a complex and highly specialized structure as the central nervous system is still unclear. Here, we reveal a crosstalk between motor neurons (MNs) and endothelial cells (ECs), necessary for the coordinated development of MNs. By analyzing cell-to-cell interaction profiles of the mouse developing spinal cord, we uncovered semaphorin 3C (Sema3C) and PlexinD1 as a communication axis between MNs and ECs. Using cell-specific knockout mice and in vitro assays, we demonstrate that removal of Sema3C in MNs, or its receptor PlexinD1 in ECs, results in premature and aberrant vascularization of MN columns. Those vascular defects impair MN axon exit from the spinal cord. Impaired PlexinD1 signaling in ECs also causes MN maturation defects at later stages. This study highlights the importance of a timely and spatially controlled communication between MNs and ECs for proper spinal cord development.
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Affiliation(s)
- José Ricardo Vieira
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany; Faculty of Biosciences, Heidelberg University, Im Neuenheimer 234, 69120 Heidelberg, Germany
| | - Bhavin Shah
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany
| | - Sebastian Dupraz
- Institute for Neurovascular Cell Biology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Isidora Paredes
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany; Faculty of Biosciences, Heidelberg University, Im Neuenheimer 234, 69120 Heidelberg, Germany
| | - Patricia Himmels
- Faculty of Biosciences, Heidelberg University, Im Neuenheimer 234, 69120 Heidelberg, Germany
| | - Géza Schermann
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany; Institute for Neurovascular Cell Biology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Heike Adler
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany
| | - Alessia Motta
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Lea Gärtner
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany
| | - Ariadna Navarro-Aragall
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Elena Ioannou
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Elena Dyukova
- Max-Planck-Institute for Heart and Lung Research, Ludwigstr. 43, 61231 Bad Nauheim, Germany
| | - Remy Bonnavion
- Max-Planck-Institute for Heart and Lung Research, Ludwigstr. 43, 61231 Bad Nauheim, Germany
| | - Andreas Fischer
- Department of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany; Division Vascular Signaling and Cancer, German Cancer Research Center Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Dario Bonanomi
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Frank Bradke
- Laboratory of Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Venusberg Campus 1/99, 53127 Bonn, Germany
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Carmen Ruiz de Almodóvar
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany; Institute for Neurovascular Cell Biology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany; Schlegel Chair for Neurovascular Cell Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany.
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11
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Schaeffer J, Weber IP, Thompson AJ, Keynes RJ, Franze K. Axons in the Chick Embryo Follow Soft Pathways Through Developing Somite Segments. Front Cell Dev Biol 2022; 10:917589. [PMID: 35874821 PMCID: PMC9304555 DOI: 10.3389/fcell.2022.917589] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
During patterning of the peripheral nervous system, motor axons grow sequentially out of the neural tube in a segmented fashion to ensure functional integration of the motor roots between the surrounding cartilage and bones of the developing vertebrae. This segmented outgrowth is regulated by the intrinsic properties of each segment (somite) adjacent to the neural tube, and in particular by chemical repulsive guidance cues expressed in the posterior half. Yet, knockout models for such repulsive cues still display initial segmentation of outgrowing motor axons, suggesting the existence of additional, yet unknown regulatory mechanisms of axon growth segmentation. As neuronal growth is not only regulated by chemical but also by mechanical signals, we here characterized the mechanical environment of outgrowing motor axons. Using atomic force microscopy-based indentation measurements on chick embryo somite strips, we identified stiffness gradients in each segment, which precedes motor axon growth. Axon growth was restricted to the anterior, softer tissue, which showed lower cell body densities than the repulsive stiffer posterior parts at later stages. As tissue stiffness is known to regulate axon growth during development, our results suggest that motor axons also respond to periodic stiffness gradients imposed by the intrinsic mechanical properties of somites.
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Affiliation(s)
- Julia Schaeffer
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- Inserm, U1216, Grenoble Institut Neurosciences, Univ. Grenoble Alpes, Grenoble, France
- *Correspondence: Julia Schaeffer, ; Kristian Franze,
| | - Isabell P. Weber
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Amelia J. Thompson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Roger J. Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- Institute of Medical Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
- *Correspondence: Julia Schaeffer, ; Kristian Franze,
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12
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Kudla AM, Miranda X, Nijhout HF. The roles of growth regulation and appendage patterning genes in the morphogenesis of treehopper pronota. Proc Biol Sci 2022; 289:20212682. [PMID: 35673859 PMCID: PMC9174728 DOI: 10.1098/rspb.2021.2682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Treehoppers of the insect family Membracidae have evolved enlarged and elaborate pronotal structures, which is hypothesized to involve co-opted expression of genes that are shared with the wings. Here, we investigate the similarity between the pronotum and wings in relation to growth. Our study reveals that the ontogenetic allometry of the pronotum is similar to that of wings in Membracidae, but not the outgroup. Using transcriptomics, we identify genes related to translation and protein synthesis, which are mutually upregulated. These genes are implicated in the eIF2, eIF4/p70S6K and mTOR pathways, and have known roles in regulating cell growth and proliferation. We find that species-specific differential growth patterning of the pronotum begins as early as the third instar, which suggests that expression of appendage patterning genes occurs long before the metamorphic molt. We propose that a network related to growth and size determination is the more likely mechanism shared with wings. However, regulators upstream of the shared genes in pronotum and wings need to be elucidated to substantiate whether co-option has occurred. Finally, we believe it will be helpful to distinguish the mechanisms leading to pronotal size from those regulating pronotal shape as we make sense of this spectacular evolutionary innovation.
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Affiliation(s)
- Anna M. Kudla
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Ximena Miranda
- Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica
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Aoyama BB, Zanetti GG, Dias EV, Athié MCP, Lopes-Cendes I, Schwambach Vieira A. Transcriptomic analysis of dorsal and ventral subiculum after induction of acute seizures by electric stimulation of the perforant pathway in rats. Hippocampus 2022; 32:436-448. [PMID: 35343006 DOI: 10.1002/hipo.23417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 11/09/2022]
Abstract
Preconditioning is a mechanism in which injuries induced by non-lethal hypoxia or seizures trigger cellular resistance to subsequent events. Norwood et al., in a 2010 study, showed that an 8-h-long period of electrical stimulation of the perforant pathway in rats is required for the induction of hippocampal sclerosis. However, in order to avoid generalized seizures, status epilepticus (SE), and death, a state of resistance to seizures must be induced in the hippocampus by a preconditioning paradigm consisting of two daily 30-min stimulation periods. Due to the importance of the subiculum in the hippocampal formation, this study aims to investigate differential gene expression patterns in the dorsal and ventral subiculum using RNA-sequencing, after induction of a preconditioning protocol by electrical stimulation of the perforant pathway. The dorsal (dSub) and ventral (vSub) subiculum regions were collected by laser-microdissection 24 h after preconditioning protocol induction in rats. RNA sequencing was performed in a Hiseq 4000 platform, reads were aligned using the STAR and DESEq2 statistics package was used to estimate gene expression. We identified 1176 differentially expressed genes comparing control to preconditioned subiculum regions, 204 genes were differentially expressed in dSub and 972 in vSub. The gene ontology enrichment analysis showed that the most significant common enrichment pathway considering up-regulated genes in dSub and vSub was steroid metabolism. In contrast, the most significant enrichment pathway considering down-regulated genes in vSub was axon guidance. Our results indicate that preconditioning induces changes in the expression of genes related to synaptic reorganization, increased cholesterol metabolism, and astrogliosis in both dSub and vSub. Both regions also presented a decrease in the expression of genes related to glutamatergic transmission and an increase in expression of genes related to complement system activation and GABAergic transmission. The down-regulation of proapoptotic and axon guidance genes in the ventral subiculum suggests that preconditioning may induce a neuroprotective environment in this region.
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Affiliation(s)
- Beatriz B Aoyama
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Gabriel G Zanetti
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Elayne V Dias
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Maria C P Athié
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil.,Department of Translational Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Iscia Lopes-Cendes
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil.,Department of Translational Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - André Schwambach Vieira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
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14
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TDP-43 is essential for Eph receptor-class-specific spinal motor axon trajectory into the limb. Neurosci Res 2021; 176:31-39. [PMID: 34687812 DOI: 10.1016/j.neures.2021.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 11/23/2022]
Abstract
During the neural circuit formation, neuronal growth cones must be guided precisely to their neuronal or muscle targets, which can be achieved by the activation of membrane-bound guidance receptors at the periphery. However, the mechanisms that regulate the temporal availability of these receptors remain largely unknown. TAR DNA binding protein-43 (TDP-43) has been proposed to bind with the mRNAs of guidance receptors, thus prompting us to investigate its role in axon guidance of the spinal lateral motor column (LMC) neurons into the limb mesenchyme. We first identified the TDP-43 expression in the LMC neurons at the stage of axons growth into the limb using in situ mRNA hybridization. The loss and gain of TDP-43 function in chick LMC neurons redirected their axon trajectory with opposite effects. In mice, a spinal motor neuron-specific TDP-43 deletion led to the misrouting of LMC axons. Further, ectopic TDP-43 expression increased EphB protein levels in LMC neurons, suggesting that TDP-43 mediates LMC pathfinding by regulating EphB expression. Finally, TDP-43 levels influenced the growth preference of LMC neurites against ephrin-B, but not Netrin-1 and Semaphorin ligands. Our results demonstrate that TDP-43 is essential for the ephrinB:EphB signaling-mediated axon trajectory selection of LMC subtypes into the limb.
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15
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Tsou YS, Wang CY, Chang MY, Hsu TI, Wu MT, Wu YH, Tsai WL, Chuang JY, Kao TJ. Vav2 is required for Netrin-1 receptor-class-specific spinal motor axon guidance. Dev Dyn 2021; 251:444-458. [PMID: 34374463 DOI: 10.1002/dvdy.409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Proper guidance of neuronal axons to their targets is required to assemble neural circuits during the development of the nervous system. However, the mechanism by which the guidance of axonal growth cones is regulated by specific intermediaries activated by receptor signaling pathways to mediate cytoskeleton dynamics is unclear. Vav protein members have been proposed to mediate this process, prompting us to investigate their role in the limb selection of the axon trajectory of spinal lateral motor column (LMC) neurons. RESULTS We found Vav2 and Vav3 expression in LMC neurons when motor axons grew into the limb. Vav2, but not Vav3, loss-of-function perturbed LMC pathfinding, while Vav2 gain-of-function exhibited the opposite effects, demonstrating that Vav2 plays an important role in motor axon growth. Vav2 knockdown also attenuated the redirectional phenotype of LMC axons induced by Dcc, but not EphA4, in vivo and lateral LMC neurite growth preference to Netrin-1 in vitro. This study showed that Vav2 knockdown and ectopic nonphosphorylable Vav2 mutant expression abolished the Src-induced stronger growth preference of lateral LMC neurites to Netrin-1, suggesting that Vav2 is downstream of Src in this context. CONCLUSIONS Vav2 is essential for Netrin-1-regulated LMC motor axon pathfinding through Src interaction.
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Affiliation(s)
- Yi-Syue Tsou
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan.,Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan.,Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan
| | - Chih-Yang Wang
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Ming-Yuan Chang
- Division of Neurosurgery, Department of Surgery, Min-Sheng General Hospital, Taoyuan, Taiwan
| | - Tsung-I Hsu
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Research Center of Neuroscience, Taipei Medical University, Taipei, Taiwan.,TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Meng-Ting Wu
- Department of Neurosurgery, Cheng Hsin General Hospital, Taipei, Taiwan.,Ph.D. Program of Electrical and Communications Engineering, Feng Chia University, Taichung, Taiwan
| | - Yi-Hsin Wu
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Wan-Ling Tsai
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan
| | - Jian-Ying Chuang
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Research Center of Neuroscience, Taipei Medical University, Taipei, Taiwan.,TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tzu-Jen Kao
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Research Center of Neuroscience, Taipei Medical University, Taipei, Taiwan.,TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
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16
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Paxillin Is Required for Proper Spinal Motor Axon Growth into the Limb. J Neurosci 2021; 41:3808-3821. [PMID: 33727334 DOI: 10.1523/jneurosci.2863-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/04/2021] [Accepted: 03/07/2021] [Indexed: 11/21/2022] Open
Abstract
To assemble the functional circuits of the nervous system, the neuronal axonal growth cones must be precisely guided to their proper targets, which can be achieved through cell-surface guidance receptor activation by ligand binding in the periphery. We investigated the function of paxillin, a focal adhesion protein, as an essential growth cone guidance intermediary in the context of spinal lateral motor column (LMC) motor axon trajectory selection in the limb mesenchyme. Using in situ mRNA detection, we first show paxillin expression in LMC neurons of chick and mouse embryos at the time of spinal motor axon extension into the limb. Paxillin loss-of-function and gain-of-function using in ovo electroporation in chick LMC neurons, of either sex, perturbed LMC axon trajectory selection, demonstrating an essential role of paxillin in motor axon guidance. In addition, a neuron-specific paxillin deletion in mice led to LMC axon trajectory selection errors. We also show that knocking down paxillin attenuates the growth preference of LMC neurites against ephrins in vitro, and erythropoietin-producing human hepatocellular (Eph)-mediated retargeting of LMC axons in vivo, suggesting paxillin involvement in Eph-mediated LMC motor axon guidance. Finally, both paxillin knockdown and ectopic expression of a nonphosphorylable paxillin mutant attenuated the retargeting of LMC axons caused by Src overexpression, implicating paxillin as a Src target in Eph signal relay in this context. In summary, our findings demonstrate that paxillin is required for motor axon guidance and suggest its essential role in the ephrin-Eph signaling pathway resulting in motor axon trajectory selection.SIGNIFICANCE STATEMENT During the development of neural circuits, precise connections need to be established among neurons or between neurons and their muscle targets. A protein family found in neurons, Eph, is essential at different stages of neural circuit formation, including nerve outgrowth and pathfinding, and is proposed to mediate the onset and progression of several neurodegenerative diseases, such as Alzheimer's disease. To investigate how Ephs relay their signals to mediate nerve growth, we investigated the function of a molecule called paxillin and found it important for the development of spinal nerve growth toward their muscle targets, suggesting its role as an effector of Eph signals. Our work could thus provide new information on how neuromuscular connectivity is properly established during embryonic development.
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17
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Spijkers XM, Pasteuning-Vuhman S, Dorleijn JC, Vulto P, Wevers NR, Pasterkamp RJ. A directional 3D neurite outgrowth model for studying motor axon biology and disease. Sci Rep 2021; 11:2080. [PMID: 33483540 PMCID: PMC7822896 DOI: 10.1038/s41598-021-81335-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 01/04/2021] [Indexed: 01/30/2023] Open
Abstract
We report a method to generate a 3D motor neuron model with segregated and directed axonal outgrowth. iPSC-derived motor neurons are cultured in extracellular matrix gel in a microfluidic platform. Neurons extend their axons into an adjacent layer of gel, whereas dendrites and soma remain predominantly in the somal compartment, as verified by immunofluorescent staining. Axonal outgrowth could be precisely quantified and was shown to respond to the chemotherapeutic drug vincristine in a highly reproducible dose-dependent manner. The model was shown susceptible to excitotoxicity upon exposure with excess glutamate and showed formation of stress granules upon excess glutamate or sodium arsenite exposure, mimicking processes common in motor neuron diseases. Importantly, outgrowing axons could be attracted and repelled through a gradient of axonal guidance cues, such as semaphorins. The platform comprises 40 chips arranged underneath a microtiter plate providing both throughput and compatibility to standard laboratory equipment. The model will thus prove ideal for studying axonal biology and disease, drug discovery and regenerative medicine.
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Affiliation(s)
- Xandor M. Spijkers
- grid.474144.6MIMETAS BV, Organ-On-a-Chip Company, 2333 CH Leiden, The Netherlands ,grid.5477.10000000120346234Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Svetlana Pasteuning-Vuhman
- grid.5477.10000000120346234Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Jennifa C. Dorleijn
- grid.474144.6MIMETAS BV, Organ-On-a-Chip Company, 2333 CH Leiden, The Netherlands
| | - Paul Vulto
- grid.474144.6MIMETAS BV, Organ-On-a-Chip Company, 2333 CH Leiden, The Netherlands
| | - Nienke R. Wevers
- grid.474144.6MIMETAS BV, Organ-On-a-Chip Company, 2333 CH Leiden, The Netherlands ,grid.10419.3d0000000089452978Department of Cell and Chemical Biology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - R. Jeroen Pasterkamp
- grid.5477.10000000120346234Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, 3584 CG Utrecht, The Netherlands
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18
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Luria V, Laufer E. The Geometry of Limb Motor Innervation is Controlled by the Dorsal-Ventral Compartment Boundary in the Chick Limbless Mutant. Neuroscience 2020; 450:29-47. [PMID: 33038447 PMCID: PMC9922539 DOI: 10.1016/j.neuroscience.2020.09.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 11/29/2022]
Abstract
Precise control of limb muscles, and ultimately of limb movement, requires accurate motor innervation. Motor innervation of the vertebrate limb is established by sequential selection of trajectories at successive decision points. Motor axons of the lateral motor column (LMC) segregate at the base of the limb into two groups that execute a choice between dorsal and ventral tissue: medial LMC axons innervate the ventral limb, whereas lateral LMC axons innervate the dorsal limb. We investigated how LMC axons are targeted to the limb using the chick mutant limbless (ll), which has a dorsal transformation of the ventral limb mesenchyme. In ll the spatial pattern of motor projections to the limb is abnormal while their targeting is normal. While extensive, the dorsal transformation of the ll ventral limb mesenchyme is incomplete whereas the generation, specification and targeting of spinal motor neurons are apparently unaffected. Thus, the dorsal-ventral motor axon segregation is an active choice that is independent of the ratio between dorsal and ventral tissue but dependent on the presence of both tissues. Therefore, the fidelity of the motor projections to the limb depends on the presence of both dorsal and ventral compartments, while the geometry of motor projections is controlled by the position of limb dorsal-ventral compartment boundary.
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Affiliation(s)
- Victor Luria
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
| | - Ed Laufer
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA.
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19
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Suter TACS, Blagburn SV, Fisher SE, Anderson-Keightly HM, D'Elia KP, Jaworski A. TAG-1 Multifunctionality Coordinates Neuronal Migration, Axon Guidance, and Fasciculation. Cell Rep 2020; 30:1164-1177.e7. [PMID: 31995756 PMCID: PMC7049094 DOI: 10.1016/j.celrep.2019.12.085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/25/2019] [Accepted: 12/22/2019] [Indexed: 11/03/2022] Open
Abstract
Neuronal migration, axon fasciculation, and axon guidance need to be closely coordinated for neural circuit assembly. Spinal motor neurons (MNs) face unique challenges during development because their cell bodies reside within the central nervous system (CNS) and their axons project to various targets in the body periphery. The molecular mechanisms that contain MN somata within the spinal cord while allowing their axons to exit the CNS and navigate to their final destinations remain incompletely understood. We find that the MN cell surface protein TAG-1 anchors MN cell bodies in the spinal cord to prevent their emigration, mediates motor axon fasciculation during CNS exit, and guides motor axons past dorsal root ganglia. TAG-1 executes these varied functions in MN development independently of one another. Our results identify TAG-1 as a key multifunctional regulator of MN wiring that coordinates neuronal migration, axon fasciculation, and axon guidance. Suter et al. demonstrate that the motor neuron cell surface molecule TAG-1 confines motor neurons to the central nervous system, promotes motor axon fasciculation, and steers motor axons past inappropriate targets. This study highlights how a single cell adhesion molecule coordinates multiple steps in neuronal wiring through partially divergent mechanisms.
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Affiliation(s)
- Tracey A C S Suter
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Sara V Blagburn
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Sophie E Fisher
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | | | - Kristen P D'Elia
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Department of Biology, Providence College, Providence, RI 02918, USA
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA.
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20
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Gonzales J, Le Berre-Scoul C, Dariel A, Bréhéret P, Neunlist M, Boudin H. Semaphorin 3A controls enteric neuron connectivity and is inversely associated with synapsin 1 expression in Hirschsprung disease. Sci Rep 2020; 10:15119. [PMID: 32934297 PMCID: PMC7492427 DOI: 10.1038/s41598-020-71865-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 07/30/2020] [Indexed: 12/27/2022] Open
Abstract
Most of the gut functions are controlled by the enteric nervous system (ENS), a complex network of enteric neurons located throughout the wall of the gastrointestinal tract. The formation of ENS connectivity during the perinatal period critically underlies the establishment of gastrointestinal motility, but the factors involved in this maturation process remain poorly characterized. Here, we examined the role of Semaphorin 3A (Sema3A) on ENS maturation and its potential implication in Hirschsprung disease (HSCR), a developmental disorder of the ENS with impaired colonic motility. We found that Sema3A and its receptor Neuropilin 1 (NRP1) are expressed in the rat gut during the early postnatal period. At the cellular level, NRP1 is expressed by enteric neurons, where it is particularly enriched at growth areas of developing axons. Treatment of primary ENS cultures and gut explants with Sema3A restricts axon elongation and synapse formation. Comparison of the ganglionic colon of HSCR patients to the colon of patients with anorectal malformation shows reduced expression of the synaptic molecule synapsin 1 in HSCR, which is inversely correlated with Sema3A expression. Our study identifies Sema3A as a critical regulator of ENS connectivity and provides a link between altered ENS connectivity and HSCR.
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Affiliation(s)
- Jacques Gonzales
- Inserm UMR1235-TENS, University of Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, 1 rue Gaston Veil, 44035, Nantes, France
| | - Catherine Le Berre-Scoul
- Inserm UMR1235-TENS, University of Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, 1 rue Gaston Veil, 44035, Nantes, France
| | - Anne Dariel
- Inserm UMR1235-TENS, University of Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, 1 rue Gaston Veil, 44035, Nantes, France.,Pediatric Surgery Department, Hôpital Timone-Enfants, Assistance Publique des Hôpitaux de Marseille, Marseille, France
| | - Paul Bréhéret
- Inserm UMR1235-TENS, University of Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, 1 rue Gaston Veil, 44035, Nantes, France
| | - Michel Neunlist
- Inserm UMR1235-TENS, University of Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, 1 rue Gaston Veil, 44035, Nantes, France
| | - Hélène Boudin
- Inserm UMR1235-TENS, University of Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, 1 rue Gaston Veil, 44035, Nantes, France.
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21
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Tenney AP, Livet J, Belton T, Prochazkova M, Pearson EM, Whitman MC, Kulkarni AB, Engle EC, Henderson CE. Etv1 Controls the Establishment of Non-overlapping Motor Innervation of Neighboring Facial Muscles during Development. Cell Rep 2020; 29:437-452.e4. [PMID: 31597102 PMCID: PMC7032945 DOI: 10.1016/j.celrep.2019.08.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 06/16/2019] [Accepted: 08/22/2019] [Indexed: 01/06/2023] Open
Abstract
The somatotopic motor-neuron projections onto their cognate target muscles are essential for coordinated movement, but how that occurs for facial motor circuits, which have critical roles in respiratory and interactive behaviors, is poorly understood. We report extensive molecular heterogeneity in developing facial motor neurons in the mouse and identify markers of subnuclei and the motor pools innervating specific facial muscles. Facial subnuclei differentiate during migration to the ventral hindbrain, where neurons with progressively later birth dates—and evolutionarily more recent functions—settle in more-lateral positions. One subpopulation marker, ETV1, determines both positional and target muscle identity for neurons of the dorsolateral (DL) subnucleus. In Etv1 mutants, many markers of DL differentiation are lost, and individual motor pools project indifferently to their own and neighboring muscle targets. The resulting aberrant activation patterns are reminiscent of the facial synkinesis observed in humans after facial nerve injury. Tenney et al. demonstrate that embryonic facial motor neurons are transcriptionally diverse as they establish somatotopic innervation of the facial muscles, a process that requires the transcription factor ETV1. Facial-motor axon-targeting errors in Etv1 mutants cause coordination of whisking and eyeblink evocative of human blepharospasm.
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Affiliation(s)
- Alan P Tenney
- Center for Motor Neuron Biology and Disease (MNC), Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
| | - Jean Livet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Timothy Belton
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Michaela Prochazkova
- Functional Genomics Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD 20892, USA
| | - Erica M Pearson
- Center for Motor Neuron Biology and Disease (MNC), Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital/Harvard Medical School, Boston, MA 02115, USA
| | - Ashok B Kulkarni
- Functional Genomics Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD 20892, USA
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital/Harvard Medical School, Boston, MA 02115, USA; Department of Ophthalmology, Boston Children's Hospital/Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Christopher E Henderson
- Center for Motor Neuron Biology and Disease (MNC), Columbia University, New York, NY 10032, USA; Columbia Stem Cell Initiative (CSCI), Columbia University, New York, NY 10032, USA; Columbia Translational Neuroscience Initiative (CTNI), Columbia University, New York, NY 10032, USA; Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA
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22
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Modular and Distinct Plexin-A4/FARP2/Rac1 Signaling Controls Dendrite Morphogenesis. J Neurosci 2020; 40:5413-5430. [PMID: 32499377 DOI: 10.1523/jneurosci.2730-19.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/29/2020] [Accepted: 05/26/2020] [Indexed: 12/26/2022] Open
Abstract
Diverse neuronal populations with distinct cellular morphologies coordinate the complex function of the nervous system. Establishment of distinct neuronal morphologies critically depends on signaling pathways that control axonal and dendritic development. The Sema3A-Nrp1/PlxnA4 signaling pathway promotes cortical neuron basal dendrite arborization but also repels axons. However, the downstream signaling components underlying these disparate functions of Sema3A signaling are unclear. Using the novel PlxnA4KRK-AAA knock-in male and female mice, generated by CRISPR/cas9, we show here that the KRK motif in the PlxnA4 cytoplasmic domain is required for Sema3A-mediated cortical neuron dendritic elaboration but is dispensable for inhibitory axon guidance. The RhoGEF FARP2, which binds to the KRK motif, shows identical functional specificity as the KRK motif in the PlxnA4 receptor. We find that Sema3A activates the small GTPase Rac1, and that Rac1 activity is required for dendrite elaboration but not axon growth cone collapse. This work identifies a novel Sema3A-Nrp1/PlxnA4/FARP2/Rac1 signaling pathway that specifically controls dendritic morphogenesis but is dispensable for repulsive guidance events. Overall, our results demonstrate that the divergent signaling output from multifunctional receptor complexes critically depends on distinct signaling motifs, highlighting the modular nature of guidance cue receptors and its potential to regulate diverse cellular responses.SIGNIFICANCE STATEMENT The proper formation of axonal and dendritic morphologies is crucial for the precise wiring of the nervous system that ultimately leads to the generation of complex functions in an organism. The Semaphorin3A-Neuropilin1/Plexin-A4 signaling pathway has been shown to have multiple key roles in neurodevelopment, from axon repulsion to dendrite elaboration. This study demonstrates that three specific amino acids, the KRK motif within the Plexin-A4 receptor cytoplasmic domain, are required to coordinate the downstream signaling molecules to promote Sema3A-mediated cortical neuron dendritic elaboration, but not inhibitory axon guidance. Our results unravel a novel Semaphorin3A-Plexin-A4 downstream signaling pathway and shed light on how the disparate functions of axon guidance and dendritic morphogenesis are accomplished by the same extracellular ligand in vivo.
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23
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Cook GM, Sousa C, Schaeffer J, Wiles K, Jareonsettasin P, Kalyanasundaram A, Walder E, Casper C, Patel S, Chua PW, Riboni-Verri G, Raza M, Swaddiwudhipong N, Hui A, Abdullah A, Wajed S, Keynes RJ. Regulation of nerve growth and patterning by cell surface protein disulphide isomerase. eLife 2020; 9:54612. [PMID: 32452761 PMCID: PMC7269675 DOI: 10.7554/elife.54612] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/23/2020] [Indexed: 02/06/2023] Open
Abstract
Contact repulsion of growing axons is an essential mechanism for spinal nerve patterning. In birds and mammals the embryonic somites generate a linear series of impenetrable barriers, forcing axon growth cones to traverse one half of each somite as they extend towards their body targets. This study shows that protein disulphide isomerase provides a key component of these barriers, mediating contact repulsion at the cell surface in chick half-somites. Repulsion is reduced both in vivo and in vitro by a range of methods that inhibit enzyme activity. The activity is critical in initiating a nitric oxide/S-nitrosylation-dependent signal transduction pathway that regulates the growth cone cytoskeleton. Rat forebrain grey matter extracts contain a similar activity, and the enzyme is expressed at the surface of cultured human astrocytic cells and rat cortical astrocytes. We suggest this system is co-opted in the brain to counteract and regulate aberrant nerve terminal growth.
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Affiliation(s)
- Geoffrey Mw Cook
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Catia Sousa
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Grenoble Institute des Neurosciences, La Tronche, France
| | - Julia Schaeffer
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Katherine Wiles
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Independent researcher, London, United Kingdom
| | - Prem Jareonsettasin
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Exeter College, Oxford, United Kingdom
| | - Asanish Kalyanasundaram
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,School of Clinical Medicine, Cambridge University Hospitals, Cambridge, United Kingdom
| | - Eleanor Walder
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,School of Clinical Medicine, Cambridge University Hospitals, Cambridge, United Kingdom
| | - Catharina Casper
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Winter, Brandl, Fürniss, Hübner, Röss, Kaiser & Polte, Partnerschaft mbB, Patent und Rechtsanwaltskanzlei, München, Germany
| | - Serena Patel
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,School of Clinical Medicine, Cambridge University Hospitals, Cambridge, United Kingdom
| | - Pei Wei Chua
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,School of Medicine and Health Sciences, Monash University, Bandar Sunway, Malaysia
| | - Gioia Riboni-Verri
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,School of Medicine, Medical Science and Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - Mansoor Raza
- Cambridge Innovation Capital, Cambridge, United Kingdom
| | - Nol Swaddiwudhipong
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Andrew Hui
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ameer Abdullah
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Saj Wajed
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,University of Exeter Medical School, Exeter, United Kingdom
| | - Roger J Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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24
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Emerson SE, Stergas HR, Bupp-Chickering SO, Ebert AM. Shootin-1 is required for nervous system development in zebrafish. Dev Dyn 2020; 249:1285-1295. [PMID: 32406957 DOI: 10.1002/dvdy.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 04/09/2020] [Accepted: 05/05/2020] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Semaphorin6A (Sema6A) and its PlexinA2 (PlxnA2) receptor canonically function as repulsive axon guidance cues. To understand downstream signaling mechanisms, we performed a microarray screen and identified the "clutch molecule" shootin-1 (shtn-1) as a transcriptionally repressed target. Shtn-1 is a key proponent of cell migration and neuronal polarization and must be regulated during nervous system development. The mechanisms of Shtn-1 regulation and the phenotypic consequences of loss of repression are poorly understood. RESULTS We demonstrate shtn-1 overexpression results in impaired migration of the optic vesicles, lack of retinal pigmented epithelium, and pathfinding errors of retinotectal projections. We also observed patterning defects in the peripheral nervous system. Importantly, these phenotypes were rescued by overexpressing PlxnA2. CONCLUSIONS We demonstrate a functional role for repression of shtn-1 by PlxnA2 in development of the eyes and peripheral nervous system in zebrafish. These results demonstrate that careful regulation of shtn-1 is critical for development of the nervous system.
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Affiliation(s)
- Sarah E Emerson
- Department of Biology, University of Vermont, Burlington, Vermont, USA
| | - Helaina R Stergas
- Department of Biology, University of Vermont, Burlington, Vermont, USA
| | | | - Alicia M Ebert
- Department of Biology, University of Vermont, Burlington, Vermont, USA
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25
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Whitman MC, Miyake N, Nguyen EH, Bell JL, Matos Ruiz PM, Chan WM, Di Gioia SA, Mukherjee N, Barry BJ, Bosley TM, Khan AO, Engle EC. Decreased ACKR3 (CXCR7) function causes oculomotor synkinesis in mice and humans. Hum Mol Genet 2020; 28:3113-3125. [PMID: 31211835 DOI: 10.1093/hmg/ddz137] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/08/2019] [Accepted: 06/10/2019] [Indexed: 01/17/2023] Open
Abstract
Oculomotor synkinesis is the involuntary movement of the eyes or eyelids with a voluntary attempt at a different movement. The chemokine receptor CXCR4 and its ligand CXCL12 regulate oculomotor nerve development; mice with loss of either molecule have oculomotor synkinesis. In a consanguineous family with congenital ptosis and elevation of the ptotic eyelid with ipsilateral abduction, we identified a co-segregating homozygous missense variant (c.772G>A) in ACKR3, which encodes an atypical chemokine receptor that binds CXCL12 and functions as a scavenger receptor, regulating levels of CXCL12 available for CXCR4 signaling. The mutant protein (p.V258M) is expressed and traffics to the cell surface but has a lower binding affinity for CXCL12. Mice with loss of Ackr3 have variable phenotypes that include misrouting of the oculomotor and abducens nerves. All embryos show oculomotor nerve misrouting, ranging from complete misprojection in the midbrain, to aberrant peripheral branching, to a thin nerve, which aberrantly innervates the lateral rectus (as seen in Duane syndrome). The abducens nerve phenotype ranges from complete absence, to aberrant projections within the orbit, to a normal trajectory. Loss of ACKR3 in the midbrain leads to downregulation of CXCR4 protein, consistent with reports that excess CXCL12 causes ligand-induced degradation of CXCR4. Correspondingly, excess CXCL12 applied to ex vivo oculomotor slices causes axon misrouting, similar to inhibition of CXCR4. Thus, ACKR3, through its regulation of CXCL12 levels, is an important regulator of axon guidance in the oculomotor system; complete loss causes oculomotor synkinesis in mice, while reduced function causes oculomotor synkinesis in humans.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Noriko Miyake
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Elaine H Nguyen
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Paola M Matos Ruiz
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Wai-Man Chan
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Silvio Alessandro Di Gioia
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Nisha Mukherjee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Brenda J Barry
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - T M Bosley
- Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Arif O Khan
- Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
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26
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Di Giaimo R, Durovic T, Barquin P, Kociaj A, Lepko T, Aschenbroich S, Breunig CT, Irmler M, Cernilogar FM, Schotta G, Barbosa JS, Trümbach D, Baumgart EV, Neuner AM, Beckers J, Wurst W, Stricker SH, Ninkovic J. The Aryl Hydrocarbon Receptor Pathway Defines the Time Frame for Restorative Neurogenesis. Cell Rep 2019; 25:3241-3251.e5. [PMID: 30566853 DOI: 10.1016/j.celrep.2018.11.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 10/10/2018] [Accepted: 11/13/2018] [Indexed: 01/11/2023] Open
Abstract
Zebrafish have a high capacity to replace lost neurons after brain injury. New neurons involved in repair are generated by a specific set of glial cells, known as ependymoglial cells. We analyze changes in the transcriptome of ependymoglial cells and their progeny after injury to infer the molecular pathways governing restorative neurogenesis. We identify the aryl hydrocarbon receptor (AhR) as a regulator of ependymoglia differentiation toward post-mitotic neurons. In vivo imaging shows that high AhR signaling promotes the direct conversion of a specific subset of ependymoglia into post-mitotic neurons, while low AhR signaling promotes ependymoglial proliferation. Interestingly, we observe the inactivation of AhR signaling shortly after injury followed by a return to the basal levels 7 days post injury. Interference with timely AhR regulation after injury leads to aberrant restorative neurogenesis. Taken together, we identify AhR signaling as a crucial regulator of restorative neurogenesis timing in the zebrafish brain.
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Affiliation(s)
- Rossella Di Giaimo
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Department of Biology, University of Naples Federico II, 80134 Naples, Italy
| | - Tamara Durovic
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Graduate School of Systemic Neurosciences, Biomedical Center of LMU, 82152 Planegg, Germany
| | - Pablo Barquin
- Universidad Pablo de Olavide, Sevilla, 41013 Sevilla, Spain
| | - Anita Kociaj
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Graduate School of Systemic Neurosciences, Biomedical Center of LMU, 82152 Planegg, Germany
| | - Tjasa Lepko
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Graduate School of Systemic Neurosciences, Biomedical Center of LMU, 82152 Planegg, Germany
| | - Sven Aschenbroich
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Graduate School of Systemic Neurosciences, Biomedical Center of LMU, 82152 Planegg, Germany
| | - Christopher T Breunig
- MCN Junior Research Group, Munich Center for Neurosciences, 82152 Munich, Germany; Epigenetic Engineering, Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Martin Irmler
- Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Filippo M Cernilogar
- Division of Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Planegg, Germany
| | - Gunnar Schotta
- Division of Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Planegg, Germany; Munich Center for Integrated Protein Science (CiPSM), 82152 Planegg, Germany
| | - Joana S Barbosa
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Dietrich Trümbach
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | | | - Andrea M Neuner
- MCN Junior Research Group, Munich Center for Neurosciences, 82152 Munich, Germany; Epigenetic Engineering, Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Johannes Beckers
- Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Technische Universität München, Chair of Experimental Genetics, 85354 Freising-Weihenstephan, Germany
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Munich Cluster for Systems Neurology SYNERGY, 82152 Planegg, Germany; German Center for Neurodegenerative Diseases (DZNE), 82152 Planegg, Germany; Chair of Developmental Genetics, Technische Universität München, 85354 Freising-Weihenstephan, Germany
| | - Stefan H Stricker
- MCN Junior Research Group, Munich Center for Neurosciences, 82152 Munich, Germany; Epigenetic Engineering, Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Jovica Ninkovic
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Department for Cell Biology and Anatomy, Biomedical Center of LMU, 82152 Planegg, Munich, Germany.
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27
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Fujiki R, Lee JY, Jurgens JA, Whitman MC, Engle EC. Isolation and Culture of Oculomotor, Trochlear, and Spinal Motor Neurons from Prenatal Islmn:GFP Transgenic Mice. J Vis Exp 2019:10.3791/60440. [PMID: 31789317 PMCID: PMC7036286 DOI: 10.3791/60440] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Oculomotor neurons (CN3s) and trochlear neurons (CN4s) exhibit remarkable resistance to degenerative motor neuron diseases such as amyotrophic lateral sclerosis (ALS) when compared to spinal motor neurons (SMNs). The ability to isolate and culture primary mouse CN3s, CN4s, and SMNs would provide an approach to study mechanisms underlying this selective vulnerability. To date, most protocols use heterogeneous cell cultures, which can confound the interpretation of experimental outcomes. To minimize the problems associated with mixed-cell populations, pure cultures are indispensable. Here, the first protocol describes in detail how to efficiently purify and cultivate CN3s/CN4s alongside SMNs counterparts from the same embryos using embryonic day 11.5 (E11.5) IslMN:GFP transgenic mouse embryos. The protocol provides details on the tissue dissection and dissociation, FACS-based cell isolation, and in vitro cultivation of cells from CN3/CN4 and SMN nuclei. This protocol adds a novel in vitro CN3/CN4 culture system to existing protocols and simultaneously provides a pure species- and age-matched SMN culture for comparison. Analyses focusing on the morphological, cellular, molecular, and electrophysiological characteristics of motor neurons are feasible in this culture system. This protocol will enable research into the mechanisms that define motor neuron development, selective vulnerability, and disease.
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Affiliation(s)
- Ryosuke Fujiki
- Department of Neurology, Boston Children's Hospital; FM Kirby Neurobiology Center, Boston Children's Hospital; Department of Neurology, Harvard Medical School; Medical Genetics Training Program, Harvard Medical School; Department of Neurology, Kokura Memorial Hospital
| | - Joun Y Lee
- Department of Neurology, Boston Children's Hospital; FM Kirby Neurobiology Center, Boston Children's Hospital; Department of Genetics, Albert Einstein College of Medicine
| | - Julie A Jurgens
- Department of Neurology, Boston Children's Hospital; FM Kirby Neurobiology Center, Boston Children's Hospital; Department of Neurology, Harvard Medical School; Broad Institute of M.I.T. and Harvard
| | - Mary C Whitman
- FM Kirby Neurobiology Center, Boston Children's Hospital; Department of Ophthalmology, Boston Children's Hospital; Department of Ophthalmology, Harvard Medical School
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital; FM Kirby Neurobiology Center, Boston Children's Hospital; Department of Neurology, Harvard Medical School; Medical Genetics Training Program, Harvard Medical School; Department of Ophthalmology, Boston Children's Hospital; Department of Ophthalmology, Harvard Medical School; Broad Institute of M.I.T. and Harvard; Howard Hughes Medical Institute;
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28
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Neuropilin 2 Signaling Mediates Corticostriatal Transmission, Spine Maintenance, and Goal-Directed Learning in Mice. J Neurosci 2019; 39:8845-8859. [PMID: 31541021 DOI: 10.1523/jneurosci.1006-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 08/09/2019] [Accepted: 09/12/2019] [Indexed: 01/25/2023] Open
Abstract
The striatum represents the main input structure of the basal ganglia, receiving massive excitatory input from the cortex and the thalamus. The development and maintenance of cortical input to the striatum is crucial for all striatal function including many forms of sensorimotor integration, learning, and action control. The molecular mechanisms regulating the development and maintenance of corticostriatal synaptic transmission are unclear. Here we show that the guidance cue, Semaphorin 3F and its receptor Neuropilin 2 (Nrp2), influence dendritic spine maintenance, corticostriatal short-term plasticity, and learning in adult male and female mice. We found that Nrp2 is enriched in adult layer V pyramidal neurons, corticostriatal terminals, and in developing and adult striatal spiny projection neurons (SPNs). Loss of Nrp2 increases SPN excitability and spine number, reduces short-term facilitation at corticostriatal synapses, and impairs goal-directed learning in an instrumental task. Acute deletion of Nrp2 selectively in adult layer V cortical neurons produces a similar increase in the number of dendritic spines and presynaptic modifications at the corticostriatal synapse in the Nrp2 -/- mouse, but does not affect the intrinsic excitability of SPNs. Furthermore, conditional loss of Nrp2 impairs sensorimotor learning on the accelerating rotarod without affecting goal-directed instrumental learning. Collectively, our results identify Nrp2 signaling as essential for the development and maintenance of the corticostriatal pathway and may shed novel insights on neurodevelopmental disorders linked to the corticostriatal pathway and Semaphorin signaling.SIGNIFICANCE STATEMENT The corticostriatal pathway controls sensorimotor, learning, and action control behaviors and its dysregulation is linked to neurodevelopmental disorders, such as autism spectrum disorder (ASD). Here we demonstrate that Neuropilin 2 (Nrp2), a receptor for the axon guidance cue semaphorin 3F, has important and previously unappreciated functions in the development and adult maintenance of dendritic spines on striatal spiny projection neurons (SPNs), corticostriatal short-term plasticity, intrinsic physiological properties of SPNs, and learning in mice. Our findings, coupled with the association of Nrp2 with ASD in human populations, suggest that Nrp2 may play an important role in ASD pathophysiology. Overall, our work demonstrates Nrp2 to be a key regulator of corticostriatal development, maintenance, and function, and may lead to better understanding of neurodevelopmental disease mechanisms.
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29
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The endosomal sorting adaptor HD-PTP is required for ephrin-B:EphB signalling in cellular collapse and spinal motor axon guidance. Sci Rep 2019; 9:11945. [PMID: 31420572 PMCID: PMC6697728 DOI: 10.1038/s41598-019-48421-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 08/02/2019] [Indexed: 12/25/2022] Open
Abstract
The signalling output of many transmembrane receptors that mediate cell-cell communication is restricted by the endosomal sorting complex required for transport (ESCRT), but the impact of this machinery on Eph tyrosine kinase receptor function is unknown. We identified the ESCRT-associated adaptor protein HD-PTP as part of an EphB2 proximity-dependent biotin identification (BioID) interactome, and confirmed this association using co-immunoprecipitation. HD-PTP loss attenuates the ephrin-B2:EphB2 signalling-induced collapse of cultured cells and axonal growth cones, and results in aberrant guidance of chick spinal motor neuron axons in vivo. HD-PTP depletion abrogates ephrin-B2-induced EphB2 clustering, and EphB2 and Src family kinase activation. HD-PTP loss also accelerates ligand-induced EphB2 degradation, contrasting the effects of HD-PTP loss on the relay of signals from other cell surface receptors. Our results link Eph function to the ESCRT machinery and demonstrate a role for HD-PTP in the earliest steps of ephrin-B:EphB signalling, as well as in obstructing premature receptor depletion.
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30
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Ragagnin AMG, Shadfar S, Vidal M, Jamali MS, Atkin JD. Motor Neuron Susceptibility in ALS/FTD. Front Neurosci 2019; 13:532. [PMID: 31316328 PMCID: PMC6610326 DOI: 10.3389/fnins.2019.00532] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/08/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the death of both upper and lower motor neurons (MNs) in the brain, brainstem and spinal cord. The neurodegenerative mechanisms leading to MN loss in ALS are not fully understood. Importantly, the reasons why MNs are specifically targeted in this disorder are unclear, when the proteins associated genetically or pathologically with ALS are expressed ubiquitously. Furthermore, MNs themselves are not affected equally; specific MNs subpopulations are more susceptible than others in both animal models and human patients. Corticospinal MNs and lower somatic MNs, which innervate voluntary muscles, degenerate more readily than specific subgroups of lower MNs, which remain resistant to degeneration, reflecting the clinical manifestations of ALS. In this review, we discuss the possible factors intrinsic to MNs that render them uniquely susceptible to neurodegeneration in ALS. We also speculate why some MN subpopulations are more vulnerable than others, focusing on both their molecular and physiological properties. Finally, we review the anatomical network and neuronal microenvironment as determinants of MN subtype vulnerability and hence the progression of ALS.
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Affiliation(s)
- Audrey M G Ragagnin
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sina Shadfar
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Marta Vidal
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Md Shafi Jamali
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julie D Atkin
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
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31
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Whitman MC, Nguyen EH, Bell JL, Tenney AP, Gelber A, Engle EC. Loss of CXCR4/CXCL12 Signaling Causes Oculomotor Nerve Misrouting and Development of Motor Trigeminal to Oculomotor Synkinesis. Invest Ophthalmol Vis Sci 2019; 59:5201-5209. [PMID: 30372748 PMCID: PMC6204880 DOI: 10.1167/iovs.18-25190] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Proper control of eye movements is critical to vision, but relatively little is known about the molecular mechanisms that regulate development and axon guidance in the ocular motor system or cause the abnormal innervation patterns (oculomotor synkinesis) seen in developmental disorders and after oculomotor nerve palsy. We developed an ex vivo slice assay that allows for live imaging and molecular manipulation of the growing oculomotor nerve, which we used to identify axon guidance cues that affect the oculomotor nerve. Methods Ex vivo slices were generated from E10.5 IslMN-GFP embryos and grown for 24 to 72 hours. To assess for CXCR4 function, the specific inhibitor AMD3100 was added to the culture media. Cxcr4cko/cko:Isl-Cre:ISLMN-GFP and Cxcl12KO/KO:ISLMN-GFP embryos were cleared and imaged on a confocal microscope. Results When AMD3100 was added to the slice cultures, oculomotor axons grew dorsally (away from the eye) rather than ventrally (toward the eye). Axons that had already exited the midbrain continued toward the eye. Loss of Cxcr4 or Cxcl12 in vivo caused misrouting of the oculomotor nerve dorsally and motor axons from the trigeminal motor nerve, which normally innervate the muscles of mastication, aberrantly innervated extraocular muscles in the orbit. This represents the first mouse model of trigeminal-oculomotor synkinesis. Conclusions CXCR4/CXCL12 signaling is critical for the initial pathfinding decisions of oculomotor axons and their proper exit from the midbrain. Failure of the oculomotor nerve to innervate its extraocular muscle targets leads to aberrant innervation by other motor neurons, indicating that muscles lacking innervation may secrete cues that attract motor axons.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Elaine H Nguyen
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Alan P Tenney
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
| | - Alon Gelber
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States.,Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
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32
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Bonanomi D, Valenza F, Chivatakarn O, Sternfeld MJ, Driscoll SP, Aslanian A, Lettieri K, Gullo M, Badaloni A, Lewcock JW, Hunter T, Pfaff SL. p190RhoGAP Filters Competing Signals to Resolve Axon Guidance Conflicts. Neuron 2019; 102:602-620.e9. [PMID: 30902550 PMCID: PMC8608148 DOI: 10.1016/j.neuron.2019.02.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 12/05/2018] [Accepted: 02/19/2019] [Indexed: 12/21/2022]
Abstract
The rich functional diversity of the nervous system is founded in the specific connectivity of the underlying neural circuitry. Neurons are often preprogrammed to respond to multiple axon guidance signals because they use sequential guideposts along their pathways, but this necessitates a strict spatiotemporal regulation of intracellular signaling to ensure the cues are detected in the correct order. We performed a mouse mutagenesis screen and identified the Rho GTPase antagonist p190RhoGAP as a critical regulator of motor axon guidance. Rather than acting as a compulsory signal relay, p190RhoGAP uses a non-conventional GAP-independent mode to transiently suppress attraction to Netrin-1 while motor axons exit the spinal cord. Once in the periphery, a subset of axons requires p190RhoGAP-mediated inhibition of Rho signaling to target specific muscles. Thus, the multifunctional activity of p190RhoGAP emerges from its modular design. Our findings reveal a cell-intrinsic gate that filters conflicting signals, establishing temporal windows of signal detection.
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Affiliation(s)
- Dario Bonanomi
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA; San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy.
| | - Fabiola Valenza
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Onanong Chivatakarn
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Matthew J Sternfeld
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Shawn P Driscoll
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Aaron Aslanian
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Karen Lettieri
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Miriam Gullo
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Aurora Badaloni
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Joseph W Lewcock
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Samuel L Pfaff
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA.
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Venkatasubramanian L, Guo Z, Xu S, Tan L, Xiao Q, Nagarkar-Jaiswal S, Mann RS. Stereotyped terminal axon branching of leg motor neurons mediated by IgSF proteins DIP-α and Dpr10. eLife 2019; 8:e42692. [PMID: 30714901 PMCID: PMC6391070 DOI: 10.7554/elife.42692] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/31/2019] [Indexed: 12/18/2022] Open
Abstract
For animals to perform coordinated movements requires the precise organization of neural circuits controlling motor function. Motor neurons (MNs), key components of these circuits, project their axons from the central nervous system and form precise terminal branching patterns at specific muscles. Focusing on the Drosophila leg neuromuscular system, we show that the stereotyped terminal branching of a subset of MNs is mediated by interacting transmembrane Ig superfamily proteins DIP-α and Dpr10, present in MNs and target muscles, respectively. The DIP-α/Dpr10 interaction is needed only after MN axons reach the vicinity of their muscle targets. Live imaging suggests that precise terminal branching patterns are gradually established by DIP-α/Dpr10-dependent interactions between fine axon filopodia and developing muscles. Further, different leg MNs depend on the DIP-α and Dpr10 interaction to varying degrees that correlate with the morphological complexity of the MNs and their muscle targets.
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Affiliation(s)
- Lalanti Venkatasubramanian
- Department of Biological SciencesColumbia UniversityNew YorkUnited States
- Department of NeuroscienceMortimer B. Zuckerman Mind Brain Behavior InstituteNew YorkUnited States
| | - Zhenhao Guo
- Department of Biological SciencesColumbia UniversityNew YorkUnited States
| | - Shuwa Xu
- Department of Biological ChemistryUniversity of California, Los AngelesLos AngelesUnited States
| | - Liming Tan
- Department of Biological ChemistryUniversity of California, Los AngelesLos AngelesUnited States
| | - Qi Xiao
- Department of Biological ChemistryUniversity of California, Los AngelesLos AngelesUnited States
| | - Sonal Nagarkar-Jaiswal
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Richard S Mann
- Department of NeuroscienceMortimer B. Zuckerman Mind Brain Behavior InstituteNew YorkUnited States
- Department of Biochemistry and Molecular BiophysicsColumbia UniversityNew YorkUnited States
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Ryu JR, Kim JH, Cho HM, Jo Y, Lee B, Joo S, Chae U, Nam Y, Cho IJ, Sun W. A monitoring system for axonal growth dynamics using micropatterns of permissive and Semaphorin 3F chemorepulsive signals. LAB ON A CHIP 2019; 19:291-305. [PMID: 30539180 DOI: 10.1039/c8lc00845k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neurons reach their correct targets by directional outgrowth of axons, which is mediated by attractive or repulsive cues. Growing axons occasionally cross a field of repulsive cues and stop at intermediate targets on the journey to their final destination. However, it is not well-understood how individual growth cones make decisions, and pass through repulsive territory to reach their permissive target regions. We developed a microcontact printing culture system that could trap individual axonal tips in a permissive dot area surrounded by the repulsive signal, semaphorin 3F (Sema3F). Axons of rat hippocampal neurons on the Sema3F/PLL dot array extended in the checkboard pattern with a significantly slow growth rate. The detailed analysis of the behaviors of axonal growth cones revealed the saccadic dynamics in the dot array system. The trapped axonal tips in the permissive area underwent growth cone enlargement with remarkably spiky filopodia, promoting their escape from the Sema3F constraints with straight extension of axons. This structured axonal growth on the dot pattern was disrupted by increased inter-dot distance, or perturbing intracellular signaling machineries. These data indicate that axons grow against repulsive signals by jumping over the repulsive cues, depending on contact signals and intracellular milieu. Our study suggests that our dot array culture system can be used as a screening system to easily and efficiently evaluate ECM or small molecule inhibitors interfering growth cone dynamics leading to controlling axonal growth.
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Affiliation(s)
- Jae Ryun Ryu
- Department of Anatomy, Brain Korea 21, Korea University College of Medicine, Anam-Dong, Sungbuk-Gu, Seoul, 136-705, Republic of Korea.
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Hirata T, Iwai L. Timing matters: A strategy for neurons to make diverse connections. Neurosci Res 2018; 138:79-83. [PMID: 30227163 DOI: 10.1016/j.neures.2018.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/21/2018] [Accepted: 08/21/2018] [Indexed: 11/18/2022]
Abstract
Neurogenesis proceeds like a continuous wave, in which each type of neurons is produced over a few days to several days. During this protracted time window, early-born and late-born neurons are sequentially produced with a considerable time lag. Even if they are identical in their genetic and molecular specifications, they could develop different characteristics under the influences of the timing of their birth. In this review, we discuss the potential influences of "timing" as a generic parameter affecting neuronal differentiation, particularly on axon guidance and connections. These ideas have rarely been tested experimentally, but may provide a new strategy by which phenotypic diversity is increased in neurons.
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Affiliation(s)
- Tatsumi Hirata
- Division of Brain Function, National Institute of Genetics, 1111 Yata, Mishima, 411-8540, Japan; SOKENDAI (Graduate University for Advanced Studies), Japan.
| | - Lena Iwai
- Division of Brain Function, National Institute of Genetics, 1111 Yata, Mishima, 411-8540, Japan
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Jardin N, Giudicelli F, Ten Martín D, Vitrac A, De Gois S, Allison R, Houart C, Reid E, Hazan J, Fassier C. BMP- and neuropilin 1-mediated motor axon navigation relies on spastin alternative translation. Development 2018; 145:dev.162701. [PMID: 30082270 PMCID: PMC6141775 DOI: 10.1242/dev.162701] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 07/16/2018] [Indexed: 12/22/2022]
Abstract
Functional analyses of genes responsible for neurodegenerative disorders have unveiled crucial links between neurodegenerative processes and key developmental signalling pathways. Mutations in SPG4-encoding spastin cause hereditary spastic paraplegia (HSP). Spastin is involved in diverse cellular processes that couple microtubule severing to membrane remodelling. Two main spastin isoforms are synthesised from alternative translational start sites (M1 and M87). However, their specific roles in neuronal development and homeostasis remain largely unknown. To selectively unravel their neuronal function, we blocked spastin synthesis from each initiation codon during zebrafish development and performed rescue analyses. The knockdown of each isoform led to different motor neuron and locomotion defects, which were not rescued by the selective expression of the other isoform. Notably, both morphant neuronal phenotypes were observed in a CRISPR/Cas9 spastin mutant. We next showed that M1 spastin, together with HSP proteins atlastin 1 and NIPA1, drives motor axon targeting by repressing BMP signalling, whereas M87 spastin acts downstream of neuropilin 1 to control motor neuron migration. Our data therefore suggest that defective BMP and neuropilin 1 signalling may contribute to the motor phenotype in a vertebrate model of spastin depletion.
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Affiliation(s)
- Nicolas Jardin
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - François Giudicelli
- Sorbonne Universités, UPMC Université Paris 06, CNRS, INSERM, Biologie du Développement Paris Seine - Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Daniel Ten Martín
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Anaïs Vitrac
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Stéphanie De Gois
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Rachel Allison
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK
| | - Corinne Houart
- Medical Research Council Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Evan Reid
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK
| | - Jamilé Hazan
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Coralie Fassier
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
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Chang CJ, Chang MY, Lee YC, Chen KY, Hsu TI, Wu YH, Chuang JY, Kao TJ. Nck2 is essential for limb trajectory selection by spinal motor axons. Dev Dyn 2018; 247:1043-1056. [DOI: 10.1002/dvdy.24656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/02/2018] [Accepted: 07/03/2018] [Indexed: 11/08/2022] Open
Affiliation(s)
- Chih-Ju Chang
- Department of Neurosurgery; Cathay General Hospital; Taipei Taiwan
- School of Medicine; Fu Jen Catholic University; New Taipei Taiwan
- Departemnt of Mechanical Engineering; National Central University; Taiwan
| | - Ming-Yuan Chang
- Division of Neurosurgery, Department of Surgery; Min-Sheng General Hospital; Taiwan
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
| | - Yi-Chao Lee
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Kai-Yun Chen
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Tsung-I Hsu
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Yi-Hsin Wu
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Jian-Ying Chuang
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Tzu-Jen Kao
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
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Latremoliere A, Cheng L, DeLisle M, Wu C, Chew S, Hutchinson EB, Sheridan A, Alexandre C, Latremoliere F, Sheu SH, Golidy S, Omura T, Huebner EA, Fan Y, Whitman MC, Nguyen E, Hermawan C, Pierpaoli C, Tischfield MA, Woolf CJ, Engle EC. Neuronal-Specific TUBB3 Is Not Required for Normal Neuronal Function but Is Essential for Timely Axon Regeneration. Cell Rep 2018; 24:1865-1879.e9. [PMID: 30110642 PMCID: PMC6155462 DOI: 10.1016/j.celrep.2018.07.029] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/03/2018] [Accepted: 07/09/2018] [Indexed: 11/27/2022] Open
Abstract
We generated a knockout mouse for the neuronal-specific β-tubulin isoform Tubb3 to investigate its role in nervous system formation and maintenance. Tubb3-/- mice have no detectable neurobehavioral or neuropathological deficits, and upregulation of mRNA and protein of the remaining β-tubulin isotypes results in equivalent total β-tubulin levels in Tubb3-/- and wild-type mice. Despite similar levels of total β-tubulin, adult dorsal root ganglia lacking TUBB3 have decreased growth cone microtubule dynamics and a decreased neurite outgrowth rate of 22% in vitro and in vivo. The effect of the 22% slower growth rate is exacerbated for sensory recovery, where fibers must reinnervate the full volume of the skin to recover touch function. Overall, these data reveal that, while TUBB3 is not required for formation of the nervous system, it has a specific role in the rate of peripheral axon regeneration that cannot be replaced by other β-tubulins.
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Affiliation(s)
- Alban Latremoliere
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Long Cheng
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Michelle DeLisle
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Chen Wu
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Sheena Chew
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Elizabeth B Hutchinson
- Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
| | - Andrew Sheridan
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Chloe Alexandre
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Shu-Hsien Sheu
- Department of Pathology and Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Sara Golidy
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Takao Omura
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA; Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Eric A Huebner
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Yanjie Fan
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Mary C Whitman
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Elaine Nguyen
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
| | - Crystal Hermawan
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Carlo Pierpaoli
- Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
| | - Max A Tischfield
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Clifford J Woolf
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Elizabeth C Engle
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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Guidance of motor axons: where do we stand? CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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40
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Schaeffer J, Tannahill D, Cioni JM, Rowlands D, Keynes R. Identification of the extracellular matrix protein Fibulin-2 as a regulator of spinal nerve organization. Dev Biol 2018; 442:101-114. [PMID: 29944871 DOI: 10.1016/j.ydbio.2018.06.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 05/24/2018] [Accepted: 06/19/2018] [Indexed: 12/11/2022]
Abstract
During amniote peripheral nervous system development, segmentation ensures the correct patterning of the spinal nerves relative to the vertebral column. Along the antero-posterior (rostro-caudal) axis, each somite-derived posterior half-sclerotome expresses repellent molecules to restrict axon growth and neural crest migration to the permissive anterior half-segment. To identify novel regulators of spinal nerve patterning, we investigated the differential gene expression of anterior and posterior half-sclerotomes in the chick embryo by RNA-sequencing. Several genes encoding extracellular matrix proteins were found to be enriched in either anterior (e.g. Tenascin-C, Laminin alpha 4) or posterior (e.g. Fibulin-2, Fibromodulin, Collagen VI alpha 2) half-sclerotomes. Among them, the extracellular matrix protein Fibulin-2 was found specifically restricted to the posterior half-sclerotome. By using in ovo ectopic expression in chick somites, we found that Fibulin-2 modulates spinal axon growth trajectories in vivo. While no intrinsic axon repellent activity of Fibulin-2 was found, we showed that it enhances the growth cone repulsive activity of Semaphorin 3A in vitro. Some molecules regulating axon growth during development are found to be upregulated in the adult central nervous system (CNS) following traumatic injury. Here, we found increased Fibulin-2 protein levels in reactive astrocytes at the lesion site of a mouse model of CNS injury. Together, these results suggest that the developing vertebral column and the adult CNS share molecular features that control axon growth and plasticity, which may open up the possibility for the identification of novel therapeutic targets for brain and spinal cord injury.
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Affiliation(s)
- Julia Schaeffer
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK.
| | | | - Jean-Michel Cioni
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK
| | | | - Roger Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK
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41
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Abstract
During nervous system development, neurons extend axons to reach their targets and form functional circuits. The faulty assembly or disintegration of such circuits results in disorders of the nervous system. Thus, understanding the molecular mechanisms that guide axons and lead to neural circuit formation is of interest not only to developmental neuroscientists but also for a better comprehension of neural disorders. Recent studies have demonstrated how crosstalk between different families of guidance receptors can regulate axonal navigation at choice points, and how changes in growth cone behaviour at intermediate targets require changes in the surface expression of receptors. These changes can be achieved by a variety of mechanisms, including transcription, translation, protein-protein interactions, and the specific trafficking of proteins and mRNAs. Here, I review these axon guidance mechanisms, highlighting the most recent advances in the field that challenge the textbook model of axon guidance.
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Affiliation(s)
- Esther T Stoeckli
- University of Zurich, Institute of Molecular Life Sciences, Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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42
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Shadrach JL, Pierchala BA. Semaphorin3A Signaling Is Dispensable for Motor Axon Reinnervation of the Adult Neuromuscular Junction. eNeuro 2018; 5:ENEURO.0155-17.2018. [PMID: 29774231 PMCID: PMC5955010 DOI: 10.1523/eneuro.0155-17.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 04/23/2018] [Accepted: 04/27/2018] [Indexed: 01/13/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that is formed by motor axon innervation of skeletal muscle fibers. The maintenance of motor-muscle connectivity is critical for the preservation of muscle tone and generation of movement. Injury can induce a robust regenerative response in motor axons, but severe trauma or chronic denervation resulting from neurodegenerative disease typically leads to inefficient repair and poor functional recovery. The axon guidance molecule Semaphorin3A (Sema3A) has been implicated as a negative regulator of motor innervation. Upon binding to a plexinA-neuropilin1 (Npn1) receptor complex, Sema3A initiates a downstream signaling cascade that results in axonal repulsion. Here, we established a reproducible nerve crush model to quantify motor nerve regeneration. We then used that model to investigate the role of Sema3A signaling at the adult NMJ. In contrast to previous findings, we found that Sema3A and Npn1 mRNA decrease in response to denervation, suggesting that Sema3A-Npn1 signaling may regulate NMJ reinnervation. To directly test that hypothesis, we used inducible knockout models to ubiquitously delete Sema3A or Npn1 from adult mice. Despite demonstrating that we could achieve highly efficient gene deletion, disruption of Sema3A-Npn1 signaling did not affect the normal maintenance of the NMJ or disrupt motor axon reinnervation after a denervating injury.
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Affiliation(s)
- Jennifer L. Shadrach
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109
- Program in Cellular and Molecular Biology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109
| | - Brian A. Pierchala
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109
- Program in Cellular and Molecular Biology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109
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Vahedi-Hunter TA, Estep JA, Rosette KA, Rutlin ML, Wright KM, Riccomagno MM. Cas Adaptor Proteins Coordinate Sensory Axon Fasciculation. Sci Rep 2018; 8:5996. [PMID: 29662228 PMCID: PMC5902548 DOI: 10.1038/s41598-018-24261-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 03/29/2018] [Indexed: 11/09/2022] Open
Abstract
Development of complex neural circuits like the peripheral somatosensory system requires intricate mechanisms to ensure axons make proper connections. While much is known about ligand-receptor pairs required for dorsal root ganglion (DRG) axon guidance, very little is known about the cytoplasmic effectors that mediate cellular responses triggered by these guidance cues. Here we show that members of the Cas family of cytoplasmic signaling adaptors are highly phosphorylated in central projections of the DRG as they enter the spinal cord. Furthermore, we provide genetic evidence that Cas proteins regulate fasciculation of DRG sensory projections. These data establish an evolutionarily conserved requirement for Cas adaptor proteins during peripheral nervous system axon pathfinding. They also provide insight into the interplay between axonal fasciculation and adhesion to the substrate.
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Affiliation(s)
- Tyler A Vahedi-Hunter
- Neuroscience Program, Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Jason A Estep
- Cell, Molecular and Developmental Biology Program, Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Kylee A Rosette
- Vollum Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Michael L Rutlin
- Department of Biochemistry and Molecular Biophysics, Columbia College of Physicians and Surgeons, Columbia University, New York, New York, 10032, USA
| | - Kevin M Wright
- Vollum Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Martin M Riccomagno
- Neuroscience Program, Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA. .,Cell, Molecular and Developmental Biology Program, Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA.
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ALS-related human cortical and motor neurons survival is differentially affected by Sema3A. Cell Death Dis 2018; 9:256. [PMID: 29449528 PMCID: PMC5833799 DOI: 10.1038/s41419-018-0294-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/31/2017] [Accepted: 01/04/2018] [Indexed: 11/08/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by cell death of upper and lower motor neurons (MNs). The cause of MN cell loss is not completely understood but involves both cell autonomous and non-cell autonomous mechanisms. Numerous molecules have been implicated to be involved in the death of MNs. One such candidate is semaphorin 3A (Sema3A). In ALS patients, Sema3A was shown to be significantly upregulated in the motor cortex and downregulated in the spinal cord. In the mouse, Sema3A was shown to be an axon repellent molecule for MNs. Sema3A could also induce death of different neuronal types that are also repelled by it, including sensory, sympathetic, retinal, and cortical neurons. In contrast, astrocyte-specific knockout of Sema3A results in motor neuron cell death, consistent with the idea that Sema3A is a survival factor for mouse motor neurons. Here, we tested the response of human cortical neurons and spinal cord MNs to Sema3A. We found that Sema3A enhances the survival of spinal cord MNs. In contrast, Sema3A reduces the survival of cortical neurons. Thus, both upregulation of Sema3A in the cortex, or downregulation in the spinal cord of ALS patients is likely to directly contribute to MNs cell loss in ALS patients.
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Ephexin1 Is Required for Eph-Mediated Limb Trajectory of Spinal Motor Axons. J Neurosci 2018; 38:2043-2056. [PMID: 29363583 DOI: 10.1523/jneurosci.2257-17.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/10/2018] [Accepted: 01/15/2018] [Indexed: 11/21/2022] Open
Abstract
The precise assembly of a functional nervous system relies on the guided migration of axonal growth cones, which is made possible by signals transmitted to the cytoskeleton by cell surface-expressed guidance receptors. We investigated the function of ephexin1, a Rho guanine nucleotide exchange factor, as an essential growth-cone guidance intermediary in the context of spinal lateral motor column (LMC) motor axon trajectory selection in the limb mesenchyme. Using in situ mRNA detection, we first show that ephexin1 is expressed in LMC neurons of chick and mouse embryos at the time of spinal motor axon extension into the limb. Ephexin1 loss of function and gain of function using in ovo electroporation in chick LMC neurons, of either sex, perturbed LMC axon trajectory selection, demonstrating an essential role of ephexin1 in motor axon guidance. In addition, ephexin1 loss in mice of either sex led to LMC axon trajectory selection errors. We also show that ephexin1 knockdown attenuates the growth preference of LMC neurites against ephrins in vitro and Eph receptor-mediated retargeting of LMC axons in vivo, suggesting that ephexin1 is required in Eph-mediated LMC motor axon guidance. Finally, both ephexin1 knockdown and ectopic expression of nonphosphorylatable ephexin1 mutant attenuated the retargeting of LMC axons caused by Src overexpression, implicating ephexin1 as an Src target in Eph signal relay in this context. In summary, our findings demonstrate that ephexin1 is essential for motor axon guidance and suggest an important role in relaying ephrin:Eph signals that mediate motor axon trajectory selection.SIGNIFICANCE STATEMENT The proper development of functioning neural circuits requires precise nerve connections among neurons or between neurons and their muscle targets. The Eph tyrosine kinase receptors expressed in neurons are important in many contexts during neural-circuit formation, such as axon outgrowth, axon guidance, and synaptic formation, and have been suggested to be involved in neurodegenerative disorders, including amyotrophic lateral sclerosis and Alzheimer's disease. To dissect the mechanism of Eph signal relay, we studied ephexin1 gain of function and loss of function and found ephexin1 essential for the development of limb nerves toward their muscle targets, concluding that it functions as an intermediary to relay Eph signaling in this context. Our work could thus shed new light on the molecular mechanisms controlling neuromuscular connectivity during embryonic development.
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Presynaptic Deficits at Neuromuscular Junctions: A Specific Cause and Potential Target of Axonal Neuropathy in Type 2 Charcot-Marie-Tooth Disease. J Neurosci 2018; 36:8067-9. [PMID: 27488627 DOI: 10.1523/jneurosci.1515-16.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/23/2016] [Indexed: 11/21/2022] Open
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Hata K, Maeno-Hikichi Y, Yumoto N, Burden SJ, Landmesser LT. Distinct Roles of Different Presynaptic and Postsynaptic NCAM Isoforms in Early Motoneuron-Myotube Interactions Required for Functional Synapse Formation. J Neurosci 2018; 38:498-510. [PMID: 29175953 PMCID: PMC5761622 DOI: 10.1523/jneurosci.1014-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 11/09/2017] [Accepted: 11/11/2017] [Indexed: 01/27/2023] Open
Abstract
The neural cell adhesion molecule (NCAM) is expressed both presynaptically and postsynaptically during neuromuscular junction formation. Genetic deletion in mice of all three isoforms (180, 140, and 120 kDa), or just the 180 isoform, suggested that different isoforms played distinct roles in synaptic maturation. Here we characterized in mice of either sex the earliest adhesive contacts between the growth cones of motoneurons and myotubes and their subsequent maturation into functional synapses in cocultures of motoneurons and myotubes, which expressed their normal complement of NCAM isoforms, or were lacking all isoforms either presynaptically or postsynaptically. Growth cone contact with +/+ mouse myotubes resulted in immediate adhesive contacts and the rapid downregulation of growth cone motility. When contacting NCAM-/- myotubes, growth cones touched and retracted/collapsed multiple times and failed to form stable contacts, even after 10 h. Exogenous expression in myotubes of either the 180 or 140 isoform, but not the 120 kDa isoform, rescued the rapid formation of stable contacts, the accumulation of presynaptic and postsynaptic molecules, and functional transmission. When NCAM was absent only in motoneurons, growth cones did not retract upon myotube contact, but, since their motility was not downregulated, they grew off the ends of the myotubes, failing to form synapses. The agrin receptor Lrp4 was strongly downregulated in NCAM-negative myotubes, and motoneuron growth cones did not make stable contacts with Lrp4-negative myotubes. These studies have identified novel roles for presynaptic and postsynaptic NCAM in mediating early cell-cell interactions required for synapse formation.SIGNIFICANCE STATEMENT Although many molecular signals needed to form the functionally effective neuromuscular synapses required for normal movement have been described, the earliest signals that let motoneuron growth cones make stable adhesive contacts with myotubes and cease motility are not well understood. Using dynamic imaging of motoneuron-myotube cocultures, we show that NCAM is required on both the growth cone and myotube and that different NCAM isoforms mediate initial adhesion and the downregulation of growth cone motility. The agrin receptor Lrp4 was also essential for initial adhesive contacts and was downregulated on NCAM-/- myotubes. Our identification of novel roles for NCAM and Lrp4 and possible interactions between them in transforming motile growth cones into stable contacts opens interesting new avenues for exploration.
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Affiliation(s)
- Katsusuke Hata
- Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106-4975
- RIKEN Brain Science Institute, Wako 351-0198, Japan, and
| | - Yuka Maeno-Hikichi
- Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106-4975
| | - Norihiro Yumoto
- Skirball Institute of Biomolecular Medicine, NYU Medical School, New York, New York 10016
| | - Steven J Burden
- Skirball Institute of Biomolecular Medicine, NYU Medical School, New York, New York 10016
| | - Lynn T Landmesser
- Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106-4975,
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Guseva D, Jakovcevski I, Irintchev A, Leshchyns’ka I, Sytnyk V, Ponimaskin E, Schachner M. Cell Adhesion Molecule Close Homolog of L1 (CHL1) Guides the Regrowth of Regenerating Motor Axons and Regulates Synaptic Coverage of Motor Neurons. Front Mol Neurosci 2018; 11:174. [PMID: 29881335 PMCID: PMC5976800 DOI: 10.3389/fnmol.2018.00174] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 05/08/2018] [Indexed: 02/05/2023] Open
Abstract
The close homolog of L1 (CHL1) is a cell adhesion molecule involved in regulation of neuronal differentiation and survival, neurite outgrowth and axon guidance during development. In the mature nervous system, CHL1 regulates synaptic activity and plasticity. The aim of the present study was to evaluate the influence of CHL1 on peripheral nerve regeneration after trauma. Using the established model of mouse femoral nerve regeneration, CHL1 knock-out mice were investigated in comparison to the wild type littermates. First, non-injured mice of both genotypes were compared regarding the synaptic phenotypes in the corresponding spinal cord segment. While no differences in phenotypes were detectable in the femoral nerve, corresponding segments in the spinal cord were observed to differ in that inhibitory perisomatic innervation of motor neurons was increased in CHL1-deficient mice, and numbers of perisomatic cholinergic synapses on motor neuronal somata were reduced. Regarding the femoral nerve after injury, CHL1-deficient mice demonstrated preferential motor axon regrowth into the saphenous vs. quadriceps branch after nerve transection upstream of the nerve bifurcation by 8 weeks after transection, indicating decreased preferential motor re-innervation. Furthermore, in injured wild-type mice, enhanced CHL1 expression was observed in regenerating axons in the proximal nerve stump upstream of the bifurcation at days 1, 3, 5, 7 and 14, and in the distal stump at days 7 and 14 after injury, when compared to non-injured mice. Injury-related upregulation of CHL1 expression was more pronounced in axons than in Schwann cells. Despite a more pronounced capacity for preferential motor axon regrowth in wild-type vs. mutant mice, only a tendency for difference in recovery of motor functions was observed between genotypes, without statistical significance Taken together, these results indicate that CHL1 is involved in peripheral nerve regeneration, because it guides regrowing axons into the appropriate nerve branch and regulates synaptic coverage in the spinal cord.
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Affiliation(s)
- Daria Guseva
- Zentrum für Molekulare Neurobiologie Hamburg, University Hospital Hamburg-Eppendorf, Hamburg, Germany
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Igor Jakovcevski
- Zentrum für Molekulare Neurobiologie Hamburg, University Hospital Hamburg-Eppendorf, Hamburg, Germany
- Department of Experimental Neurophysiology, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Andrey Irintchev
- Department of Otorhinolaryngology, Jena University Hospital, Jena, Germany
| | - Iryna Leshchyns’ka
- School of Biotechnology and Biomolecular Sciences, South Western Sydney Clinical School, The University of New South Wales, Sydney, NSW, Australia
| | - Vladimir Sytnyk
- School of Biotechnology and Biomolecular Sciences, South Western Sydney Clinical School, The University of New South Wales, Sydney, NSW, Australia
| | - Evgeni Ponimaskin
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Melitta Schachner
- Department of Cell Biology and Neuroscience, W. M. Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, United States
- Center for Neuroscience, Shantou University Medical College, Shantou, China
- *Correspondence: Melitta Schachner
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Abstract
Motor neurons of the spinal cord are responsible for the assembly of neuromuscular connections indispensable for basic locomotion and skilled movements. A precise spatial relationship exists between the position of motor neuron cell bodies in the spinal cord and the course of their axonal projections to peripheral muscle targets. Motor neuron innervation of the vertebrate limb is a prime example of this topographic organization and by virtue of its accessibility and predictability has provided access to fundamental principles of motor system development and neuronal guidance. The seemingly basic binary map established by genetically defined motor neuron subtypes that target muscles in the limb is directed by a surprisingly large number of directional cues. Rather than being simply redundant, these converging signaling pathways are hierarchically linked and cooperate to increase the fidelity of axon pathfinding decisions. A current priority is to determine how multiple guidance signals are integrated by individual growth cones and how they synergize to delineate class-specific axonal trajectories.
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Affiliation(s)
- Dario Bonanomi
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.
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Abstract
A prominent anatomical feature of the peripheral nervous system is the segmentation of mixed (motor, sensory and autonomic) spinal nerves alongside the spinal cord. During early development their axon growth cones avoid the developing vertebral elements by traversing the anterior/cranial half of each somite-derived sclerotome, so ensuring the separation of spinal nerves from vertebral bones as axons extend towards their peripheral targets. A glycoprotein expressed on the surface of posterior half-sclerotome cells confines growth cones to the anterior half-sclerotomes by contact repulsion. A closely similar glycoprotein is expressed in avian and mammalian grey matter, where we hypothesize it may have evolved to regulate neural plasticity in birds and mammals.
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Affiliation(s)
- Roger Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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