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Blake TCA, Fox HM, Urbančič V, Ravishankar R, Wolowczyk A, Allgeyer ES, Mason J, Danuser G, Gallop JL. Filopodial protrusion driven by density-dependent Ena-TOCA-1 interactions. J Cell Sci 2024; 137:jcs261057. [PMID: 38323924 PMCID: PMC11006392 DOI: 10.1242/jcs.261057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
Filopodia are narrow actin-rich protrusions with important roles in neuronal development where membrane-binding adaptor proteins, such as I-BAR- and F-BAR-domain-containing proteins, have emerged as upstream regulators that link membrane interactions to actin regulators such as formins and proteins of the Ena/VASP family. Both the adaptors and their binding partners are part of diverse and redundant protein networks that can functionally compensate for each other. To explore the significance of the F-BAR domain-containing neuronal membrane adaptor TOCA-1 (also known as FNBP1L) in filopodia we performed a quantitative analysis of TOCA-1 and filopodial dynamics in Xenopus retinal ganglion cells, where Ena/VASP proteins have a native role in filopodial extension. Increasing the density of TOCA-1 enhances Ena/VASP protein binding in vitro, and an accumulation of TOCA-1, as well as its coincidence with Ena, correlates with filopodial protrusion in vivo. Two-colour single-molecule localisation microscopy of TOCA-1 and Ena supports their nanoscale association. TOCA-1 clusters promote filopodial protrusion and this depends on a functional TOCA-1 SH3 domain and activation of Cdc42, which we perturbed using the small-molecule inhibitor CASIN. We propose that TOCA-1 clusters act independently of membrane curvature to recruit and promote Ena activity for filopodial protrusion.
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Affiliation(s)
- Thomas C. A. Blake
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Helen M. Fox
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Vasja Urbančič
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Roshan Ravishankar
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Adam Wolowczyk
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Edward S. Allgeyer
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Julia Mason
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jennifer L. Gallop
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
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2
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Le VH, Orniacki C, Murcia-Belmonte V, Denti L, Schütz D, Stumm R, Ruhrberg C, Erskine L. CXCL12 promotes the crossing of retinal ganglion cell axons at the optic chiasm. Development 2024; 151:dev202446. [PMID: 38095299 PMCID: PMC10820821 DOI: 10.1242/dev.202446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/07/2023] [Indexed: 01/13/2024]
Abstract
Binocular vision requires the segregation of retinal ganglion cell (RGC) axons extending from the retina into the ipsilateral and contralateral optic tracts. RGC axon segregation occurs at the optic chiasm, which forms at the ventral diencephalon midline. Using expression analyses, retinal explants and genetically modified mice, we demonstrate that CXCL12 (SDF1) is required for axon segregation at the optic chiasm. CXCL12 is expressed by the meninges bordering the optic pathway, and CXCR4 by both ipsilaterally and contralaterally projecting RGCs. CXCL12 or ventral diencephalon meninges potently promoted axon outgrowth from both ipsilaterally and contralaterally projecting RGCs. Further, a higher proportion of axons projected ipsilaterally in mice lacking CXCL12 or its receptor CXCR4 compared with wild-type mice as a result of misrouting of presumptive contralaterally specified RGC axons. Although RGCs also expressed the alternative CXCL12 receptor ACKR3, the optic chiasm developed normally in mice lacking ACKR3. Our data support a model whereby meningeal-derived CXCL12 helps drive axon growth from CXCR4-expressing RGCs towards the diencephalon midline, enabling contralateral axon growth. These findings further our understanding of the molecular and cellular mechanisms controlling optic pathway development.
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Affiliation(s)
- Viet-Hang Le
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen,Foresterhill, Aberdeen AB25 2ZD, UK
| | - Clarisse Orniacki
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen,Foresterhill, Aberdeen AB25 2ZD, UK
| | - Verónica Murcia-Belmonte
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen,Foresterhill, Aberdeen AB25 2ZD, UK
- Instituto de Neurociencias de Alicante (Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH), Campus San Juan, Av. Ramón y Cajal s/n, Alicante 03550, Spain
| | - Laura Denti
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Dagmar Schütz
- Institute for Pharmacology/Toxicology, Jena University Hospital,Drackendorfer Str. 1, D-07747 Jena, Germany
| | - Ralf Stumm
- Institute for Pharmacology/Toxicology, Jena University Hospital,Drackendorfer Str. 1, D-07747 Jena, Germany
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Lynda Erskine
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen,Foresterhill, Aberdeen AB25 2ZD, UK
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Alfadil E, Bradke F. Moving through the crowd. Where are we at understanding physiological axon growth? Semin Cell Dev Biol 2023; 140:63-71. [PMID: 35817655 DOI: 10.1016/j.semcdb.2022.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 01/28/2023]
Abstract
Axon growth enables the rapid wiring of the central nervous system. Understanding this process is a prerequisite to retriggering it under pathological conditions, such as a spinal cord injury, to elicit axon regeneration. The last decades saw progress in understanding the mechanisms underlying axon growth. Most of these studies employed cultured neurons grown on flat surfaces. Only recently studies on axon growth were performed in 3D. In these studies, physiological environments exposed more complex and dynamic aspects of axon development. Here, we describe current views on axon growth and highlight gaps in our knowledge. We discuss how axons interact with the extracellular matrix during development and the role of the growth cone and its cytoskeleton within. Finally, we propose that the time is ripe to study axon growth in a more physiological setting. This will help us uncover the physiologically relevant mechanisms underlying axon growth, and how they can be reactivated to induce axon regeneration.
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Affiliation(s)
- Eissa Alfadil
- Laboratory of Axon Growth and Regeneration, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Venusberg-Campus 1, Building 99, 53127, Bonn, Germany.
| | - Frank Bradke
- Laboratory of Axon Growth and Regeneration, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Venusberg-Campus 1, Building 99, 53127, Bonn, Germany
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4
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Gu X, Jia C, Wang J. Advances in Understanding the Molecular Mechanisms of Neuronal Polarity. Mol Neurobiol 2023; 60:2851-2870. [PMID: 36738353 DOI: 10.1007/s12035-023-03242-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 01/22/2023] [Indexed: 02/05/2023]
Abstract
The establishment and maintenance of neuronal polarity are important for neural development and function. Abnormal neuronal polarity establishment commonly leads to a variety of neurodevelopmental disorders. Over the past three decades, with the continuous development and improvement of biological research methods and techniques, we have made tremendous progress in the understanding of the molecular mechanisms of neuronal polarity establishment. The activity of positive and negative feedback signals and actin waves are both essential in this process. They drive the directional transport and aggregation of key molecules of neuronal polarity, promote the spatiotemporal regulation of ordered and coordinated interactions of actin filaments and microtubules, stimulate the specialization and growth of axons, and inhibit the formation of multiple axons. In this review, we focus on recent advances in these areas, in particular the important findings about neuronal polarity in two classical models, in vitro primary hippocampal/cortical neurons and in vivo cortical pyramidal neurons, and discuss our current understanding of neuronal polarity..
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Affiliation(s)
- Xi Gu
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Chunhong Jia
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
| | - Junhao Wang
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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Mahadik SS, Lundquist EA. TOM-1/tomosyn acts with the UNC-6/netrin receptor UNC-5 to inhibit growth cone protrusion in Caenorhabditis elegans. Development 2023; 150:306234. [PMID: 37014062 PMCID: PMC10112904 DOI: 10.1242/dev.201031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 01/24/2023] [Indexed: 04/05/2023]
Abstract
In the polarity/protrusion model of growth cone repulsion from UNC-6/netrin, UNC-6 first polarizes the growth cone of the VD motor neuron axon via the UNC-5 receptor, and then regulates protrusion asymmetrically across the growth cone based on this polarity. UNC-6 stimulates protrusion dorsally through the UNC-40/DCC receptor, and inhibits protrusion ventrally through UNC-5, resulting in net dorsal growth. Previous studies showed that UNC-5 inhibits growth cone protrusion via the flavin monooxygenases and potential destabilization of F-actin, and via UNC-33/CRMP and restriction of microtubule plus-end entry into the growth cone. We show that UNC-5 inhibits protrusion through a third mechanism involving TOM-1/tomosyn. A short isoform of TOM-1 inhibited protrusion downstream of UNC-5, and a long isoform had a pro-protrusive role. TOM-1/tomosyn inhibits formation of the SNARE complex. We show that UNC-64/syntaxin is required for growth cone protrusion, consistent with a role of TOM-1 in inhibiting vesicle fusion. Our results are consistent with a model whereby UNC-5 utilizes TOM-1 to inhibit vesicle fusion, resulting in inhibited growth cone protrusion, possibly by preventing the growth cone plasma membrane addition required for protrusion.
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Affiliation(s)
- Snehal S Mahadik
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, 5049 Haworth Hall, Lawrence, KS 66045, USA
| | - Erik A Lundquist
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, 5049 Haworth Hall, Lawrence, KS 66045, USA
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6
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Zou Y. Inter- growth cone communications mediated by planar cell polarity pathway in axon guidance. Dev Biol 2022; 490:50-52. [PMID: 35788000 DOI: 10.1016/j.ydbio.2022.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 06/21/2022] [Accepted: 06/29/2022] [Indexed: 11/26/2022]
Abstract
The emergence of exquisitely organized axonal projections is one of the greatest wonders of nervous system development. In addition to growing along stereotyped directions, axons join one another as they extend to form highly organized projections. Axon-axon interactions are essential for axon guidance during nervous system wiring. Axonal growth cones recognize cell surface guidance cues on axons and either grow along the axons or away from the axons. However, it is less well understood whether and how the growth cones communicate with each other and, if so, what do these interactions mean. Recent studies from our lab provided direct evidence that the growth cones do interact with each other during axon pathfinding. And this interaction is regulated by highly regulated protein-protein interactions among components of the planar cell polarity pathway. The disruption of these interactions lead to guidance defects and disorganization of axons. We propose that these local inter-growth cone PCP signaling reinforces and increases the sensitivity of the growth cone response to shallow Wnt gradients to turn in a precise and organized fashion.
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Affiliation(s)
- Yimin Zou
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA.
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7
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Atherton J, Stouffer M, Francis F, Moores CA. Visualising the cytoskeletal machinery in neuronal growth cones using cryo-electron tomography. J Cell Sci 2022; 135:274968. [PMID: 35383828 PMCID: PMC9016625 DOI: 10.1242/jcs.259234] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/02/2022] [Indexed: 12/12/2022] Open
Abstract
Neurons extend axons to form the complex circuitry of the mature brain. This depends on the coordinated response and continuous remodelling of the microtubule and F-actin networks in the axonal growth cone. Growth cone architecture remains poorly understood at nanoscales. We therefore investigated mouse hippocampal neuron growth cones using cryo-electron tomography to directly visualise their three-dimensional subcellular architecture with molecular detail. Our data showed that the hexagonal arrays of actin bundles that form filopodia penetrate and terminate deep within the growth cone interior. We directly observed the modulation of these and other growth cone actin bundles by alteration of individual F-actin helical structures. Microtubules with blunt, slightly flared or gently curved ends predominated in the growth cone, frequently contained lumenal particles and exhibited lattice defects. Investigation of the effect of absence of doublecortin, a neurodevelopmental cytoskeleton regulator, on growth cone cytoskeleton showed no major anomalies in overall growth cone organisation or in F-actin subpopulations. However, our data suggested that microtubules sustained more structural defects, highlighting the importance of microtubule integrity during growth cone migration. Summary: Cryo-electron tomographic reconstruction of neuronal growth cone subdomains reveals distinctive F-actin and microtubule cytoskeleton architectures and modulation at molecular detail.
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Affiliation(s)
- Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King's College, London SE1 1YR, UK.,Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
| | - Melissa Stouffer
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France.,Institute of Science and Technology Austria, Am campus 1, 3400 Klosterneuberg, Austria
| | - Fiona Francis
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
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8
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Sharma A, Schwarzbauer JE. Differential Regulation of Neurite Outgrowth and Growth Cone Morphology by 3D Fibronectin and Fibronectin-Collagen Extracellular Matrices. Mol Neurobiol 2022; 59:1112-23. [PMID: 34845592 DOI: 10.1007/s12035-021-02637-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/02/2021] [Indexed: 02/03/2023]
Abstract
The extracellular matrix (ECM) plays a critical role in development, homeostasis, and regeneration of tissue structures and functions. Cell interactions with the ECM are dynamic and cells respond to ECM remodeling by changes in morphology and motility. During nerve regeneration, the ECM facilitates neurite outgrowth and guides axons with target specificity. Decellularized ECMs retain structural, biochemical, and biomechanical cues of native ECM and have the potential to replace damaged matrix to support cell activities during tissue repair. To determine the ECM components that contribute to nerve regeneration, we analyzed neuron-ECM interactions on two types of decellularized ECM. One matrix was composed primarily of fibronectin (FN) fibrils, and the other FN-rich ECM also contained significant numbers of type I collagen (COL I) fibrils. Using primary neurons dissociated from superior cervical ganglion (SCG) explants, we found that neurites were extended on both matrices without a significant difference in average neurite length after 24 h. The most distinctive features of neurites on the FN matrix were numerous short actin-filled protrusions and longer branches extending from neurite shafts. Very few protrusions and branches were detected on FN-COL matrix. Growth cone morphologies also differed with mostly filopodial growth cones on FN matrix whereas on FN-COL matrix, equivalent numbers of filopodial and slender growth cones were formed. Our work provides new information about how changes in major components of the ECM during tissue repair modulate neuron and growth cone morphologies and helps to define the contributions of neuron-ECM interactions to nerve development and regeneration.
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Takei N, Yokomaku D, Yamada T, Nagano T, Kakita A, Namba H, Ushiki T, Takahashi H, Nawa H. EGF Downregulates Presynaptic Maturation and Suppresses Synapse Formation In Vitro and In Vivo. Neurochem Res 2022; 47:2632-2644. [PMID: 34984589 DOI: 10.1007/s11064-021-03524-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 11/27/2022]
Abstract
Neuronal differentiation, maturation, and synapse formation are regulated by various growth factors. Here we show that epidermal growth factor (EGF) negatively regulates presynaptic maturation and synapse formation. In cortical neurons, EGF maintained axon elongation and reduced the sizes of growth cones in culture. Furthermore, EGF decreased the levels of presynaptic molecules and number of presynaptic puncta, suggesting that EGF inhibits neuronal maturation. The reduction of synaptic sites is confirmed by the decreased frequencies of miniature EPSCs. In vivo analysis revealed that while peripherally administrated EGF decreased the levels of presynaptic molecules and numbers of synaptophysin-positive puncta in the prefrontal cortices of neonatal rats, EGF receptor inhibitors upregulated these indexes, suggesting that endogenous EGF receptor ligands suppress presynaptic maturation. Electron microscopy further revealed that EGF decreased the numbers, but not the sizes, of synaptic structures in vivo. These findings suggest that endogenous EGF and/or other EGF receptor ligands negatively modulates presynaptic maturation and synapse formation.
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Affiliation(s)
- Nobuyuki Takei
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan.
- Department of Brain Tumor Biology, Brain Research Institute, Niigata University, Niigata, Japan.
| | - Daisaku Yokomaku
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Takaho Yamada
- Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
- Department of Hematology, Endocrinology and Metabolism, Niigata University Faculty of Medicine, Niigata, Japan
| | - Tadasato Nagano
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
- Department of Health and Nutrition, Faculty of Human Life Studies, University of Niigata Prefecture, Niigata, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hisaaki Namba
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
- Department of Physiological Science, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama, Japan
| | - Tatsuo Ushiki
- Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Hitoshi Takahashi
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
- Department of Physiological Science, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama, Japan
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10
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Miyata K, Hayashi K. The Difference in the Cytoskeletal Machinery of Growth Cones of Growing Axons and Leading Processes. Dev Neurosci 2022; 44:455-465. [PMID: 35100584 DOI: 10.1159/000522200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/22/2022] [Indexed: 11/19/2022] Open
Abstract
Neuronal migration and axon elongation in the developing brain are essential events for neural network formation. Leading processes of migrating neurons and elongating axons have growth cones at their tips. Cytoskeletal machinery for advance of growth cones of the two processes has been thought the same. In this study, we compared axonal-elongating growth cones and leading-process growth cones in the same conditions that manipulated filopodia, lamellipodia, and drebrin, the latter mediates actin filament-microtubule interaction. Cerebral cortex (CX) neurons and medial ganglionic eminence (MGE) neurons from embryonic mice were cultured on less-adhesive cover glasses. Inhibition of filopodia formation by triple knockdown of mammalian-enabled, Ena-VASP-like, and vasodilator-stimulated phosphoprotein or double knockdown of Daam1 and fascin affected axon formation of CX neurons but did not affect the morphology of leading process of MGE neurons. On the other hand, treatment with CK666, to inhibit lamellipodia formation, did not affect axons but destroyed the leading-process growth cones. When drebrin was knocked down, the morphology of CX neurons remained unchanged, but the leading processes of MGE neurons became shorter. In vivo assay of radial migration of CX neurons revealed that drebrin knockdown inhibited migration, while it did not affect axon elongation. These results showed that the filopodia-microtubule system is the main driving machinery in elongating growth cones, while the lamellipodia-drebrin-microtubule system is the main system in leading-process growth cones of migrating neurons.
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Affiliation(s)
- Kaho Miyata
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
| | - Kensuke Hayashi
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
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11
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Yasodharababu M, Nair AK. Predicting neurite extension for varying extracellular matrix stiffness and topography. J Biomech 2021; 131:110897. [PMID: 34954524 DOI: 10.1016/j.jbiomech.2021.110897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 10/19/2022]
Abstract
Neurite extension is a dynamic process and is dependent on the microenvironment. The mechanical properties of the extracellular matrix (ECM), such as stiffness and topography influence the microenvironment and affects neurite extension; however, the mechanistic basis for this dynamic response of neurite extension remains elusive. In this study, we develop a computational model that predicts neurite extension dynamics process as the stiffness and patterned topography of ECM changes. The model includes the contribution of receptors integrin and neural cellular adhesion molecule toward the growth of neurite tip. We use non-linear finite element analysis (FEA) to model the neuronal cell, neurite, and the ECM, which is then coupled to the force-deformation receptor properties obtained from molecular dynamics simulations. Using an empirical relation, we develop a neurite extension algorithm that simulates the dynamic process of growth cone induced by growth cone extension, receptor density, and rupture. We investigate the dependence of neurite extension on ECM stiffness using three distinct materials, the effect of width and spacing of continuous (cylindrical) and discontinuous (pillar) patterned topography, as well as the topography steepness and stiffness gradient. We find that an increasing stiffness and width of patterned topography results in increased neurite extension, but the magnitude of the increase differs depending on the growth cone extension and receptor density between them. These findings will aid in vitro studies in determining an ECM with appropriate mechanical properties, such as stiffness and topography that will improve neurite extension, thus resulting in the formation of functional neurons.
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Affiliation(s)
- Mohan Yasodharababu
- Multiscale Materials Modeling Lab, Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Arun K Nair
- Multiscale Materials Modeling Lab, Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR, USA; Institute for Nanoscience and Engineering, 731 W. Dickson Street, University of Arkansas, Fayetteville, AR, USA.
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12
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Abstract
Since the pioneering work of Ramón y Cajal, scientists have sought to unravel the complexities of axon development underlying neural circuit formation. Micrometer-scale axonal growth cones navigate to targets that are often centimeters away. To reach their targets, growth cones react to dynamic environmental cues that change in the order of seconds to days. Proper axon growth and guidance are essential to circuit formation, and progress in imaging has been integral to studying these processes. In particular, advances in high- and super-resolution microscopy provide the spatial and temporal resolution required for studying developing axons. In this Review, we describe how improved microscopy has revolutionized our understanding of axonal development. We discuss how novel technologies, specifically light-sheet and super-resolution microscopy, led to new discoveries at the cellular scale by imaging axon outgrowth and circuit wiring with extreme precision. We next examine how advanced microscopy broadened our understanding of the subcellular dynamics driving axon growth and guidance. We finally assess the current challenges that the field of axonal biology still faces for imaging axons, and examine how future technology could meet these needs.
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Affiliation(s)
- Cory J Weaver
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Fabienne E Poulain
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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13
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Vinton J, Aninweze A, Birgbauer E. Ibuprofen does not inhibit RhoA-mediated growth cone collapse of embryonic chicken retinal axons by LPA. Exp Brain Res 2021; 239:2969-2977. [PMID: 34322723 DOI: 10.1007/s00221-021-06172-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 05/15/2021] [Indexed: 11/28/2022]
Abstract
Lysophosphatidic acid (LPA) is a bioactive lysophospholipid that causes neuronal growth cones to collapse and neurites to retract through a RhoA-ROCK mediated pathway. It has been reported that the NSAID ibuprofen improves regeneration after spinal cord injury through a mechanism of inhibiting RhoA. This leads to the hypothesis that ibuprofen should block LPA-mediated growth cone collapse. We tested this hypothesis by treating embryonic chick retinal neurons with ibuprofen followed by LPA. Retinal growth cones collapsed with LPA in the presence of ibuprofen similar to control; however, growth cone collapse was effectively blocked by a ROCK inhibitor. Thus, our results do not support the designation of ibuprofen as a direct RhoA inhibitor.
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Affiliation(s)
- James Vinton
- Department of Biology, Winthrop University, Rock Hill, SC, 29733, USA
| | - Adaeze Aninweze
- Department of Biology, Winthrop University, Rock Hill, SC, 29733, USA
| | - Eric Birgbauer
- Department of Biology, Winthrop University, Rock Hill, SC, 29733, USA.
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14
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Kundu T, Dutta P, Nagar D, Maiti S, Ghose A. Coupling of dynamic microtubules to F-actin by Fmn2 regulates chemotaxis of neuronal growth cones. J Cell Sci 2021; 134:jcs252916. [PMID: 34313311 DOI: 10.1242/jcs.252916] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 05/26/2021] [Indexed: 12/20/2022] Open
Abstract
Dynamic co-regulation of the actin and microtubule subsystems enables the highly precise and adaptive remodelling of the cytoskeleton necessary for critical cellular processes, such as axonal pathfinding. The modes and mediators of this interpolymer crosstalk, however, are inadequately understood. We identify Fmn2, a non-diaphanous-related formin associated with cognitive disabilities, as a novel regulator of cooperative actin-microtubule remodelling in growth cones of both chick and zebrafish neurons. We show that Fmn2 stabilizes microtubules in the growth cones of cultured spinal neurons and in vivo. Super-resolution imaging revealed that Fmn2 facilitates guidance of exploratory microtubules along actin bundles into the chemosensory filopodia. Using live imaging, biochemistry and single-molecule assays, we show that a C-terminal domain in Fmn2 is necessary for the dynamic association between microtubules and actin filaments. In the absence of the cross-bridging function of Fmn2, filopodial capture of microtubules is compromised, resulting in destabilized filopodial protrusions and deficits in growth cone chemotaxis. Our results uncover a critical function for Fmn2 in actin-microtubule crosstalk in neurons and demonstrate that the modulation of microtubule dynamics via associations with F-actin is central to directional motility.
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Affiliation(s)
- Tanushree Kundu
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Priyanka Dutta
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Dhriti Nagar
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
| | - Sankar Maiti
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - Aurnab Ghose
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
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15
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Schneider F, Duong TA, Metz I, Winkelmeier J, Hübner CA, Endesfelder U, Rust MB. Mutual functional dependence of cyclase-associated protein 1 (CAP1) and cofilin1 in neuronal actin dynamics and growth cone function. Prog Neurobiol 2021; 202:102050. [PMID: 33845164 DOI: 10.1016/j.pneurobio.2021.102050] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/14/2021] [Accepted: 04/07/2021] [Indexed: 01/20/2023]
Abstract
Neuron connectivity depends on growth cones that navigate axons through the developing brain. Growth cones protrude and retract actin-rich structures to sense guidance cues. These cues control local actin dynamics and steer growth cones towards attractants and away from repellents, thereby directing axon outgrowth. Hence, actin binding proteins (ABPs) moved into the focus as critical regulators of neuron connectivity. We found cyclase-associated protein 1 (CAP1), an ABP with unknown brain function, abundant in growth cones. Super-resolution microscopy and live cell imaging combined with pharmacological approaches on hippocampal neurons from gene-targeted mice revealed a crucial role for CAP1 in actin dynamics that is critical for growth cone morphology and function. Growth cone defects in CAP1 knockout (KO) neurons compromised neuron differentiation and was associated with impaired neuron connectivity in CAP1-KO brains. Mechanistically, by rescue experiments in double KO neurons lacking CAP1 and the key actin regulator cofilin1, we demonstrated that CAP1 was essential for cofilin1 function in growth cone actin dynamics and morphology and vice versa. Together, we identified CAP1 as a novel actin regulator in growth cones that was relevant for neuron connectivity, and we demonstrated functional interdependence of CAP1 and cofilin1 in neuronal actin dynamics and growth cone function.
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Affiliation(s)
- Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany; DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Thuy-An Duong
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany
| | - Isabell Metz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany
| | - Jannik Winkelmeier
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043, Marburg, Germany; Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, USA
| | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, 07743, Jena, Germany
| | - Ulrike Endesfelder
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043, Marburg, Germany; Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, USA
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany; DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany.
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16
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Lee SJ, Zdradzinski MD, Sahoo PK, Kar AN, Patel P, Kawaguchi R, Aguilar BJ, Lantz KD, McCain CR, Coppola G, Lu Q, Twiss JL. Selective axonal translation of the mRNA isoform encoding prenylated Cdc42 supports axon growth. J Cell Sci 2021; 134:237797. [PMID: 33674450 DOI: 10.1242/jcs.251967] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 02/24/2021] [Indexed: 12/13/2022] Open
Abstract
The small Rho-family GTPase Cdc42 has long been known to have a role in cell motility and axon growth. The eukaryotic Ccd42 gene is alternatively spliced to generate mRNAs with two different 3' untranslated regions (UTRs) that encode proteins with distinct C-termini. The C-termini of these Cdc42 proteins include CaaX and CCaX motifs for post-translational prenylation and palmitoylation, respectively. Palmitoyl-Cdc42 protein was previously shown to contribute to dendrite maturation, while the prenyl-Cdc42 protein contributes to axon specification and its mRNA was detected in neurites. Here, we show that the mRNA encoding prenyl-Cdc42 isoform preferentially localizes into PNS axons and this localization selectively increases in vivo during peripheral nervous system (PNS) axon regeneration. Functional studies indicate that prenyl-Cdc42 increases axon length in a manner that requires axonal targeting of its mRNA, which, in turn, needs an intact C-terminal CaaX motif that can drive prenylation of the encoded protein. In contrast, palmitoyl-Cdc42 has no effect on axon growth but selectively increases dendrite length. Together, these data show that alternative splicing of the Cdc42 gene product generates an axon growth promoting, locally synthesized prenyl-Cdc42 protein. This article has an associated First Person interview with one of the co-first authors of the paper.
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Affiliation(s)
- Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Matthew D Zdradzinski
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Priyanka Patel
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Riki Kawaguchi
- Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA
| | - Byron J Aguilar
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Kelsey D Lantz
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Caylee R McCain
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Giovanni Coppola
- Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA.,Department of Neurology, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA
| | - Qun Lu
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
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17
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Vicenzi S, Foa L, Gasperini RJ. Serotonin functions as a bidirectional guidance molecule regulating growth cone motility. Cell Mol Life Sci 2021; 78:2247-2262. [PMID: 32939562 PMCID: PMC11072016 DOI: 10.1007/s00018-020-03628-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/14/2020] [Accepted: 08/21/2020] [Indexed: 02/02/2023]
Abstract
The neurotransmitter serotonin has been implicated in a range of complex neurological disorders linked to alterations of neuronal circuitry. Serotonin is synthesized in the developing brain before most neuronal circuits become fully functional, suggesting that serotonin might play a distinct regulatory role in shaping circuits prior to its function as a classical neurotransmitter. In this study, we asked if serotonin acts as a guidance cue by examining how serotonin alters growth cone motility of rodent sensory neurons in vitro. Using a growth cone motility assay, we found that serotonin acted as both an attractive and repulsive guidance cue through a narrow concentration range. Extracellular gradients of 50 µM serotonin elicited attraction, mediated by the serotonin 5-HT2a receptor while 100 µM serotonin elicited repulsion mediated by the 5-HT1b receptor. Importantly, high resolution imaging of growth cones indicated that these receptors signalled through their canonical pathways of endoplasmic reticulum-mediated calcium release and cAMP depletion, respectively. This novel characterisation of growth cone motility in response to serotonin gradients provides compelling evidence that secreted serotonin acts at the molecular level as an axon guidance cue to shape neuronal circuit formation during development.
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Affiliation(s)
- Silvia Vicenzi
- School of Medicine, University of Tasmania, Hobart, Australia
| | - Lisa Foa
- School of Psychological Sciences, University of Tasmania, Hobart, Australia
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18
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Pinto-Costa R, Sousa MM. Microtubules, actin and cytolinkers: how to connect cytoskeletons in the neuronal growth cone. Neurosci Lett 2021; 747:135693. [PMID: 33529653 DOI: 10.1016/j.neulet.2021.135693] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/12/2021] [Accepted: 01/16/2021] [Indexed: 01/20/2023]
Abstract
Cytolinkers ensure the integration of the different cytoskeleton components in the neuronal growth cone during development and in the course of axon regeneration. In neurons, an integrated skeleton guarantees appropriate function, and connectivity of high order circuits. Over the past years, several cytoskeleton regulatory proteins with actin-microtubule crosslinking activity have been identified. In neurons, the importance of spectrins, formins and other cytolinkers capable of coupling actin and microtubules has been extensively highlighted during axon outgrowth and guidance. In this Review, we discuss the current knowledge on cytolinkers specifically expressed in the neuronal growth cone of developing and regenerating axons.
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Affiliation(s)
- Rita Pinto-Costa
- Nerve Regeneration Group, i3S-Instituto de Investigação e Inovação em Saúde and IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
| | - Monica Mendes Sousa
- Nerve Regeneration Group, i3S-Instituto de Investigação e Inovação em Saúde and IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal.
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19
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Abstract
As the nervous system develops, newly differentiated neurons need to extend their axons toward their synaptic targets to form functional neural circuits. During this highly dynamic process of axon pathfinding, guidance receptors expressed at the tips of motile axons interact with soluble guidance cues or membrane tethered molecules present in the environment to be either attracted toward or repelled away from the source of these cues. As competing cues are often present at the same location and during the same developmental period, guidance receptors need to be both spatially and temporally regulated in order for the navigating axons to make appropriate guidance decisions. This regulation is exerted by a diverse array of molecular mechanisms that have come into focus over the past several decades and these mechanisms ensure that the correct complement of surface receptors is present on the growth cone, a fan-shaped expansion at the tip of the axon. This dynamic, highly motile structure is defined by a lamellipodial network lining the periphery of the growth cone interspersed with finger-like filopodial projections that serve to explore the surrounding environment. Once axon guidance receptors are deployed at the right place and time at the growth cone surface, they respond to their respective ligands by initiating a complex set of signaling events that serve to rearrange the growth cone membrane and the actin and microtubule cytoskeleton to affect axon growth and guidance. In this review, we highlight recent advances that shed light on the rich complexity of mechanisms that regulate axon guidance receptor distribution, activation and downstream signaling.
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Affiliation(s)
- Yixin Zang
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Karina Chaudhari
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Greg J Bashaw
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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20
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Abstract
Reactive oxygen species (ROS) are critical for maintaining cellular homeostasis and function when produced in physiological ranges. Important sources of cellular ROS include NADPH oxidases (Nox), which are evolutionary conserved multi-subunit transmembrane proteins. Nox-mediated ROS regulate variety of biological processes including hormone synthesis, calcium signaling, cell migration, and immunity. ROS participate in intracellular signaling by introducing post-translational modifications to proteins and thereby altering their functions. The central nervous system (CNS) expresses different Nox isoforms during both development and adulthood. Here, we review the role of Nox-mediated ROS during CNS development. Specifically, we focus on how individual Nox isoforms contribute to signaling in neural stem cell maintenance and neuronal differentiation, as well as neurite outgrowth and guidance. We also discuss how ROS regulates the organization and dynamics of the actin cytoskeleton in the neuronal growth cone. Finally, we review recent evidence that Nox-derived ROS modulate axonal regeneration upon nervous system injury.
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Affiliation(s)
- Aslihan Terzi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA; Bindley Bioscience Center, Purdue University, West Lafayette, IN, 47907, USA.
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21
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Yamada H, Hoshino F, Lu Q, Sakane F. Cellular phosphatidic acid sensor, α-synuclein N-terminal domain, detects endogenous phosphatidic acid in macrophagic phagosomes and neuronal growth cones. Biochem Biophys Rep 2020; 22:100769. [PMID: 32490215 DOI: 10.1016/j.bbrep.2020.100769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/05/2020] [Indexed: 11/22/2022] Open
Abstract
Phosphatidic acid (PA) is the simplest phospholipid and is involved in the regulation of various cellular events. Recently, we developed a new PA sensor, the N-terminal region of α-synuclein (α-Syn-N). However, whether α-Syn-N can sense physiologically produced, endogenous PA remains unclear. We first established an inactive PA sensor (α-Syn-N-KQ) as a negative control by replacing all eleven lysine residues with glutamine residues. Using confocal microscopy, we next verified that α-Syn-N, but not α-Syn-N-KQ, detected PA in macrophagic phagosomes in which PA is known to be enriched, further indicating that α-Syn-N can be used as a reliable PA sensor in cells. Finally, because PA generated during neuronal differentiation is critical for neurite outgrowth, we investigated the subcellular distribution of PA using α-Syn-N. We found that α-Syn-N, but not α-Syn-N-KQ, accumulated at the peripheral regions (close to the plasma membrane) of neuronal growth cones. Experiments using a phospholipase D (PLD) inhibitor strongly suggested that PA in the peripheral regions of the growth cone was primarily produced by PLD. Our findings provide a reliable sensor of endogenous PA and novel insights into the distribution of PA during neuronal differentiation.
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Key Words
- DGK, diacylglycerol kinase
- DMEM, Dulbecco's modified Eagle's medium
- Diacylglycerol kinase
- F-actin, filamentous actin
- FIPI, 5-fluoro-2-indolyl deschlorohalopemide
- Growth cone
- LPA, lysophosphatidic acid
- LPAAT, LPA acyltransferase
- Lipid sensor
- Myr, myristoylated
- PA, phosphatidic acid
- PABD, phosphatidic acid-binding domain
- PC, phosphatidylcholine
- PLD, phospholipase D
- Phagosome
- Phosphatidic acid
- Phospholipase D
- α-Syn, α-synuclein
- α-Syn-N, N-terminal region of α-Syn
- α-Synuclein
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22
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McElmurry K, Stone JE, Ma D, Lamoureux P, Zhang Y, Steidemann M, Fix L, Huang F, Miller KE, Suter DM. Dynein-mediated microtubule translocation powering neurite outgrowth in chick and Aplysia neurons requires microtubule assembly. J Cell Sci 2020; 133:133/8/jcs232983. [PMID: 32332091 DOI: 10.1242/jcs.232983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 03/02/2020] [Indexed: 12/22/2022] Open
Abstract
Previously, we have shown that bulk microtubule (MT) movement correlates with neurite elongation, and blocking either dynein activity or MT assembly inhibits both processes. However, whether the contributions of MT dynamics and dynein activity to neurite elongation are separate or interdependent is unclear. Here, we investigated the underlying mechanism by testing the roles of dynein and MT assembly in neurite elongation of Aplysia and chick neurites using time-lapse imaging, fluorescent speckle microscopy, super-resolution imaging and biophysical analysis. Pharmacologically inhibiting either dynein activity or MT assembly reduced neurite elongation rates as well as bulk and individual MT anterograde translocation. Simultaneously suppressing both processes did not have additive effects, suggesting a shared mechanism of action. Single-molecule switching nanoscopy revealed that inhibition of MT assembly decreased the association of dynein with MTs. Finally, inhibiting MT assembly prevented the rise in tension induced by dynein inhibition. Taken together, our results suggest that MT assembly is required for dynein-driven MT translocation and neurite outgrowth.
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Affiliation(s)
- Kristi McElmurry
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jessica E Stone
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Donghan Ma
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Phillip Lamoureux
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Yueyun Zhang
- Department of Statistics, Purdue University, West Lafayette, IN 47904, USA
| | - Michelle Steidemann
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Lucas Fix
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Fang Huang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Kyle E Miller
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA .,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA.,Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA.,Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
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23
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Tran AP, Warren PM, Silver J. Regulation of autophagy by inhibitory CSPG interactions with receptor PTPσ and its impact on plasticity and regeneration after spinal cord injury. Exp Neurol 2020; 328:113276. [PMID: 32145250 DOI: 10.1016/j.expneurol.2020.113276] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/15/2022]
Abstract
Chondroitin sulfate proteoglycans (CSPGs), extracellular matrix molecules that increase dramatically following a variety of CNS injuries or diseases, have long been known for their potent capacity to curtail cell migrations as well as axon regeneration and sprouting. The inhibition can be conferred through binding to their major cognate receptor, Protein Tyrosine Phosphatase Sigma (PTPσ). However, the precise mechanisms downstream of receptor binding that mediate growth inhibition have remained elusive. Recently, CSPGs/PTPσ interactions were found to regulate autophagic flux at the axon growth cone by dampening the autophagosome-lysosomal fusion step. Because of the intense interest in autophagic phenomena in the regulation of a wide variety of critical cellular functions, we summarize here what is currently known about dysregulation of autophagy following spinal cord injury, and highlight this critical new mechanism underlying axon regeneration failure. Furthermore, we review how CSPGs/PTPσ interactions influence plasticity through autophagic regulation and how PTPσ serves as a switch to execute either axon outgrowth or synaptogenesis. This has exciting implications for the role CSPGs play not only in axon regeneration failure after spinal cord injury, but also in neurodegenerative diseases where, again, inhibitory CSPGs are upregulated.
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Affiliation(s)
- Amanda Phuong Tran
- Seattle Children's Hospital Research Institute, Integrative Center for Brain Research, Seattle, Washington, USA
| | - Philippa Mary Warren
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Guy's Campus, London Bridge, London, UK
| | - Jerry Silver
- Case Western Reserve University, School of Medicine, Department of Neurosciences, Cleveland, OH, USA.
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24
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Gopalakrishna R, Mades A, Oh A, Zhu A, Nguyen J, Lin C, Kindy MS, Mack WJ. Cyclic-AMP induces Nogo-A receptor NgR1 internalization and inhibits Nogo-A-mediated collapse of growth cone. Biochem Biophys Res Commun 2020; 523:678-84. [PMID: 31948754 DOI: 10.1016/j.bbrc.2020.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 01/03/2020] [Indexed: 11/24/2022]
Abstract
The promotion of axonal regeneration is required for functional recovery from stroke and various neuronal injuries. However, axonal regeneration is inhibited by diverse axonal growth inhibitors, such as Nogo-A. Nogo-66, a C-terminal domain of Nogo-A, binds to the Nogo-A receptor 1 (NgR1) and induces the collapse of growth cones and inhibits neurite outgrowth. NgR1 is also a receptor for additional axonal growth inhibitors, suggesting it is an important target for the prevention of axonal growth inhibition. By using the indirect immunofluorescence method, we show for the first time that a cell-permeable cAMP analog (dibutyryl-cAMP) induced a rapid decrease in the cell surface expression of NgR1 in Neuroscreen-1 (NS-1) cells. The biotinylation method revealed that cAMP indeed induced internalization of NgR1 within minutes. Other intracellular cAMP-elevating agents, such as forskolin, which directly activates adenylyl cyclase, and rolipram, which inhibits cyclic nucleotide phosphodiesterase, also induced this process. This internalization was found to be reversible and influenced by intracellular levels of cAMP. Using selective activators and inhibitors of protein kinase A (PKA) and the exchange protein directly activated by cAMP (Epac), we found that NgR1 internalization is independent of PKA, but dependent on Epac. The decrease in cell surface expression of NgR1 desensitized NS-1 cells to Nogo-66-induced growth cone collapse. Therefore, it is likely that besides axonal growth inhibitors affecting neurons, neurons themselves also self-regulate their sensitivity to axonal growth inhibitors, as influenced by intracellular cAMP/Epac. This normal cellular regulatory mechanism may be pharmacologically exploited to overcome axonal growth inhibitors, and enhance functional recovery after stroke and neuronal injuries.
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25
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Abstract
The development of a functional nervous system entails establishing connectivity between appropriate synaptic partners. During axonal pathfinding, the developing axon navigates through the extracellular environment, extending toward postsynaptic targets. In the early 1900s, Ramon y Cajal suggested that the growth cone, a specialized, dynamic, and cytoskeletal-rich structure at the tip of the extending axon, is guided by chemical cues in the extracellular environment. A century of work supports this hypothesis and introduced myriad guidance cues and receptors that promote a variety of growth cone behaviors including extension, pause, collapse, retraction, turning, and branching. Here, we highlight research from the last two years regarding pathways implicated in axon pathfinding.
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Affiliation(s)
- Laura E McCormick
- UNC Department of Cell Biology and Physiology, 111 Mason Farm Road, Chapel Hill, NC, 27599, USA
| | - Stephanie L Gupton
- UNC Department of Cell Biology and Physiology, 111 Mason Farm Road, Chapel Hill, NC, 27599, USA; UNC Neuroscience Center, 115 Mason Farm Road, Chapel Hill, NC, 27599, USA; UNC Lineberger Comprehensive Cancer Center, 101 Manning Dr, Chapel Hill, NC, 27514, USA.
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26
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Ishikawa Y, Okada M, Honda A, Ito Y, Tamada A, Endo N, Igarashi M. Phosphorylation sites of microtubule-associated protein 1B (MAP 1B) are involved in axon growth and regeneration. Mol Brain 2019; 12:93. [PMID: 31711525 PMCID: PMC6849251 DOI: 10.1186/s13041-019-0510-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/10/2019] [Indexed: 01/29/2023] Open
Abstract
The growth cone is a specialized structure that forms at the tip of extending axons in developing and regenerating neurons. This structure is essential for accurate synaptogenesis at developmental stages, and is also involved in plasticity-dependent synaptogenesis and axon regeneration in the mature brain. Thus, understanding the molecular mechanisms utilized by growth cones is indispensable to understanding neuronal network formation and rearrangement. Phosphorylation is the most important and commonly utilized protein modification in signal transduction. We previously identified microtubule-associated protein 1B (MAP 1B) as the most frequently phosphorylated protein among ~ 1200 phosphorylated proteins. MAP 1B has more than 10 phosphorylation sites that were present more than 50 times among these 1200 proteins. Here, we produced phospho-specific antibodies against phosphorylated serines at positions 25 and 1201 of MAP 1B that specifically recognize growing axons both in cultured neurons and in vivo in various regions of the embryonic brain. Following sciatic nerve injury, immunoreactivity with each antibody increased compared to the sham operated group. Experiments with transected and sutured nerves revealed that regenerating axons were specifically recognized by these antibodies. These results suggest that these MAP 1B phosphorylation sites are specifically involved in axon growth and that phospho-specific antibodies against MAP 1B are useful markers of growing/regenerating axons.
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Affiliation(s)
- Yuya Ishikawa
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata, Japan.,Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan
| | - Masayasu Okada
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan.,Trans-disciplinary Research Programs, Brain Research Institute, Niigata University, Niigata, Japan.,Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Atsuko Honda
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan
| | - Yasuyuki Ito
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan
| | - Atsushi Tamada
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan.,Trans-disciplinary Research Programs, Brain Research Institute, Niigata University, Niigata, Japan.,Department of iPS Cell Applied Medicine, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan
| | - Naoto Endo
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan. .,Trans-disciplinary Research Programs, Brain Research Institute, Niigata University, Niigata, Japan.
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Xu J, Xu M, Wang Y, Mathena RP, Wen J, Zhang P, Furmanski O, Mintz CD. Anesthetics disrupt growth cone guidance cue sensing through actions on the GABA A α2 receptor mediated by the immature chloride gradient. Neurotoxicol Teratol 2019; 74:106812. [PMID: 31251980 DOI: 10.1016/j.ntt.2019.106812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/25/2019] [Accepted: 06/24/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND General anesthetics (GAs) may exert harmful effects on the developing brain by disrupting neuronal circuit formation. Anesthetics that act on γ-aminobutyric acid (GABA) receptors can interfere with axonal growth cone guidance, a critical process in the assembly of neuronal circuitry. Here we investigate the mechanism by which isoflurane prevents sensing of the repulsive guidance cue, Semaphorin 3A (Sema3A). METHODS Growth cone sensing was assayed by measuring growth cone collapse in dissociated neocortical cultures exposed to recombinant Sema3A in the presence or absence of isoflurane and/or a panel of reagents with specific actions on components of the GABA receptor and chloride ion systems. RESULTS Isoflurane exposure prevents Sema3A induced growth cone collapse. A GABAA α2 specific agonist replicates this effect (36.83 ± 3.417% vs 70.82 ± 2.941%, in the Sema3A induced control group, p < 0.0001), but an α1-specific agonist does not. Both a Na-K-Cl cotransporter 1 antagonism (bumetanide, BUM) and a chloride ionophore (IONO) prevent isoflurane from disrupting growth cone sensing of Sema3A. (65.67 ± 3.775% in Iso + BUM group vs 67.45 ± 3.624% in Sema3A induced control group, 65.34 ± 1.678% in Iso + IONO group vs 68.71 ± 2.071% in Sema3A induced control group, no significant difference) (n = 96 growth cones per group). CONCLUSION Our data suggest that the effects of isoflurane on growth cone sensing are mediated by the α2 subunit of the GABAA receptor and also that they are dependent on the developmental chloride gradient, in which Cl- exhibits a depolarizing effect. These findings provide a rationale for why immature neurons are particularly susceptible to anesthetic toxicity.
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Affiliation(s)
- Jing Xu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, 710004, China; Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael Xu
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - YuChia Wang
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - R Paige Mathena
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jieqiong Wen
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, 710004, China; Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pengbo Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, 710004, China
| | - Orion Furmanski
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - C David Mintz
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Igarashi M, Okuda S. Evolutionary analysis of proline-directed phosphorylation sites in the mammalian growth cone identified using phosphoproteomics. Mol Brain 2019; 12:53. [PMID: 31151465 PMCID: PMC6545026 DOI: 10.1186/s13041-019-0476-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 05/27/2019] [Indexed: 12/15/2022] Open
Abstract
The growth cone is essential for nerve growth and axon regeneration, which directly form and rearrange the neural network. Recently, to clarify the molecular signaling pathways in the growth cone that utilize protein phosphorylation, we performed a phosphoproteomics study of mammalian growth cone membranes derived from the developing rodent brain and identified > 30,000 phosphopeptides from ~ 1200 proteins. We found that the phosphorylation sites were highly proline directed and primarily mitogen-activated protein kinase (MAPK) dependent, due to particular activation of c-jun N-terminal protein kinase (JNK), a member of the MAPK family. Because the MAPK/JNK pathway is also involved in axon regeneration of invertebrate model organisms such Caenorhabditis elegans and Drosophila, we performed evolutionary bioinformatics analysis of the mammalian growth cone phosphorylation sites. Although these sites were generally conserved within vertebrates, they were not necessarily conserved in these invertebrate model organisms. In particular, high-frequency phosphorylation sites (> 20 times) were less conserved than low-frequency sites. Taken together, the mammalian growth cones contain a large number of vertebrate-specific phosphorylation sites and stronger dependence upon MAPK/JNK than C. elegans or Drosophila. We conclude that axon growth/regeneration likely involves many vertebrate-specific phosphorylation sites.
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Affiliation(s)
- Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan.
| | - Shujiro Okuda
- Laboratory of Bioinformatics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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29
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Trzeciecka A, Bhattacharya SK. Dataset of growth cone-enriched lipidome and proteome of embryonic to early postnatal mouse brain. Data Brief 2019; 24:103865. [PMID: 31016214 PMCID: PMC6468181 DOI: 10.1016/j.dib.2019.103865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/07/2019] [Accepted: 03/12/2019] [Indexed: 11/06/2022] Open
Abstract
A growth cone is a part of a neuron considered as a hub for axon growth, motility and guidance functions. Growth cones are thought to play a critical role during development of neurons. Growth cones also play a significant role in adult regeneration. Here, we present a dataset on the lipid and protein profiling of the growth cone-enriched fractions derived from C57BL/6J mice forebrains of developmental stage: E18, P0, P3, P6, and P9. For comparison, we analyzed non-growth cone membranes from the same samples. Lipid data is available at the Metabolomics Workbench [http://www.metabolomicsworkbench.org (Project ID: PR000746)]. Protein data is available at Proteomics Identifications (PRIDE) partner repository (PRIDE identifier PXD012134).
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Affiliation(s)
- Anna Trzeciecka
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miami, FL 33136, USA
| | - Sanjoy K Bhattacharya
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miami, FL 33136, USA
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Nguyen XTA, Tran TH, Cojoc D, Legname G. Copper Binding Regulates Cellular Prion Protein Function. Mol Neurobiol 2019; 56:6121-6133. [PMID: 30729399 DOI: 10.1007/s12035-019-1510-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 01/24/2019] [Indexed: 01/27/2023]
Abstract
The cellular prion protein (PrPC), mainly known for its role in neurodegenerative diseases, is involved in several physiological processes including neuritogenesis. In addition, its ability to bind copper or zinc has been suggested for its role in metal homeostasis. Although PrPC has been known as a copper-binding molecule, little is known about how copper can affect PrPC physiological functions. By combining genomic approaches, cellular assays, and focal stimulation technique, we found that PrPC neuritogenesis function is directly influenced by N-terminal copper-binding amino acids. Several recombinant mouse PrP (recMoPrP) mutants at N-terminal copper-binding sites were produced, and primary hippocampal cultures were treated either in bulk or exposed near the hippocampal growth cones (GC) of single neurons in local stimulation manner. While focal stimulation of GC with wild-type recMoPrP induced neurite outgrowth and rapid GC turning toward the source, N-terminal mutants fail to support this effect. Indeed, disrupting all the copper-binding sites at the N-terminus of PrPC was toxic to neurons indicating that these regions are crucial for the protein function. Mutants at both octarepeat and non-octarepeat region abolished the neuritogenesis effect. Altogether, our findings indicate the crucial role of copper-binding sites in maintaining the neuritogenesis function in PrP, suggesting a potential link between loss-of-function of the protein and disease initiation.
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Affiliation(s)
- Xuan T A Nguyen
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Thanh Hoa Tran
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Dan Cojoc
- Optical Manipulation (OM)-Lab, Institute of Materials (IOM), Consiglio Nazionale delle Ricerche (CNR), Trieste, Italy.
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
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31
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Zhao F, Li J, Wang R, Xu H, Ma K, Kong X, Sun Z, Niu X, Jiang J, Liu B, Li B, Duan F, Chen X. Exendin-4 promotes actin cytoskeleton rearrangement and protects cells from Nogo-A-Δ20 mediated spreading inhibition and growth cone collapse by down-regulating RhoA expression and activation via the PI3K pathway. Biomed Pharmacother 2018; 109:135-143. [PMID: 30396070 DOI: 10.1016/j.biopha.2018.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/03/2018] [Accepted: 10/03/2018] [Indexed: 10/27/2022] Open
Abstract
Exendin-4 is a protein of the GLP-1 family currently used to treat diabetes. Recently, a greater number of biological properties have been associated with the GLP-1 family. Our data shows that exendin-4 treatment significantly increases the cytoskeleton rearrangement, which leads to an increasingly differentiated phenotype and reduced cell migration. We also found that exendin-4 could prevent SH-SY5Y and PC12 cells from Nogo-A-Δ20 mediated spreading inhibition and neurite collapse. Western blot analysis indicated that exendin-4 treatment both reduced the expression and activation of RhoA via the PI3K signaling pathway. These data suggest that exendin-4 may protect nerve regeneration by preventing the inhibition of Nogo-A via down-regulating RhoA expression and activation.
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Affiliation(s)
- Fei Zhao
- Affiliated Hospital of the Logistics University of the Chinese People's Armed Police Force and Jinzhou Medical University Cooperative Training Center, Tianjin, 300162, China; Jinzhou Medical University, Jinzhou, Liaoning Province, 121001, China; Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Jianwei Li
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Renjie Wang
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Huiyou Xu
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Ke Ma
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Xianbin Kong
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China; Graduate school of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Zhonglei Sun
- Affiliated Hospital of the Logistics University of the Chinese People's Armed Police Force and Jinzhou Medical University Cooperative Training Center, Tianjin, 300162, China; Jinzhou Medical University, Jinzhou, Liaoning Province, 121001, China; Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Xuegang Niu
- Affiliated Hospital of the Logistics University of the Chinese People's Armed Police Force and Jinzhou Medical University Cooperative Training Center, Tianjin, 300162, China; Jinzhou Medical University, Jinzhou, Liaoning Province, 121001, China; Tianjin Fourth Central Hospital, Tianjin, 300140, China
| | - Jipeng Jiang
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Baohu Liu
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China; Wang Jing Hospital of China Academy of Chinese Medical Sciences, Beijing, 100102, China
| | - Bo Li
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China
| | - Feng Duan
- College of Computer and Control Engineering, Nankai University, Tianjin, 300071, China.
| | - Xuyi Chen
- Tianjin Key Laboratory of Neurotrauma Repair, Institute of Traumatic Brain Injury and Neuroscience, Center for Neurology and Neurosurgery, Affiliated Hospital of The Logistics University of the Chinese People's Armed Police Force, Tianjin, 300162, China.
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Zou JL, Sun JH, Qiu S, Chen SH, He FL, Li JC, Mao HQ, Liu XL, Quan DP, Zeng YS, Zhu QT. Spatial distribution affects the role of CSPGs in nerve regeneration via the actin filament-mediated pathway. Exp Neurol 2018; 307:37-44. [PMID: 29852179 DOI: 10.1016/j.expneurol.2018.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 11/28/2022]
Abstract
CSPGs are components of the extracellular matrix in the nervous system, where they serve as cues for axon guidance during development. After a peripheral nerve injury, CSPGs switch roles and become axon inhibitors and become diffusely distributed at the injury site. To investigate whether the spatial distribution of CSPGs affects their role, we combined in vitro DRG cultures with CSPG stripe or coverage assays to simulate the effect of a patterned substrate or dispersive distribution of CSPGs on growing neurites. We observed neurite steering at linear CSPG interfaces and neurite inhibition when diffused CSPGs covered the distal but not the proximal segment of the neurite. The repellent and inhibitory effects of CSPGs on neurite outgrowth were associated with the disappearance of focal actin filaments on growth cones. The application of an actin polymerization inducer, jasplakinolide, allowed neurites to break through the CSPG boundary and grow on CSPG-coated surfaces. The results of our study collectively reveal a novel mechanism that explains how the spatial distribution of CSPGs determines whether they act as a cue for axon guidance or as an axon-inhibiting factor. Increasing our understanding of this issue may promote the development of novel therapeutic strategies that regulate the spatial distributions of CSPGs to use them as an axon guidance cue.
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Affiliation(s)
- Jian-Long Zou
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Jia-Hui Sun
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, Guangdong 510080, China
| | - Shuai Qiu
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Shi-Hao Chen
- PCFM Lab, GD HPPC Lab, School of Chemistry, Sun Yat-sen University, Guangzhou, Guangdong 510127, China
| | - Fu-Lin He
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Jia-Chun Li
- Orthopedics Department, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong 510630, China
| | - Hai-Quan Mao
- Institute for NanoBioTechnology, Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xiao-Lin Liu
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China; Guangdong Provincial Peripheral Nerve Tissue-engineering and Technology Research Center, Guangzhou 510080, China
| | - Da-Ping Quan
- PCFM Lab, GD HPPC Lab, School of Chemistry, Sun Yat-sen University, Guangzhou, Guangdong 510127, China
| | - Yuan-Shan Zeng
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, Guangdong 510080, China
| | - Qing-Tang Zhu
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China; Guangdong Provincial Peripheral Nerve Tissue-engineering and Technology Research Center, Guangzhou 510080, China.
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Hoshi O, Sugizaki A, Cho Y, Takei N. BDNF Reduces eEF2 Phosphorylation and Enhances Novel Protein Synthesis in the Growth Cones of Dorsal Root Ganglia Neurons. Neurochem Res 2018; 43:1242-1249. [PMID: 29736615 DOI: 10.1007/s11064-018-2541-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/19/2018] [Accepted: 04/27/2018] [Indexed: 11/26/2022]
Abstract
The local translation, which is regulated by extracellular stimuli such as guidance molecules, in growth cones of neurons provides a molecular mechanism for axonal development. In this study, we performed immunocytochemistry together with atomic force microscopy to investigate the localization of ribosomal proteins in the growth cones of rat dorsal root ganglion (DRG) neurons. The immunoreactivity of ribosomal protein P0/1/2 and S6, and novel protein synthesis were observed in the central, sterically bulky region of growth cones. Brain derived neurotrophic factor (BDNF) reduced the eEF2 phosphorylation, indicating its activation, and enhanced protein synthesis within 30 min. The effects of BDNF were completely inhibited by rapamycin, an inhibitor of mammalian target of rapamycin (mTOR). These results indicated that BDNF rapidly activates translation and enhances novel protein synthesis in growth cones of DRG though the mTOR signaling.
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Affiliation(s)
- Osamu Hoshi
- Department of Anatomy and Physiological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
| | - Ayana Sugizaki
- Department of Anatomy and Physiological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yuichiro Cho
- Department of Anatomy and Physiological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Nobuyuki Takei
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan.
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Abstract
The directional trajectory of growing peripheral nerve axons in the adult impacts their successful regeneration to denervated target tissues. Misdirected axons in neuromas, injured nerve trunks, or nerves with attempted repair diminish the success of regeneration. The behavior of adult rodent peripheral sensory neurons in vitro, in turn, is helpful in predicting axonal behavior in vivo. Here, we describe the adaptation of embryonic neuron growth cone turning assays, an important technique in developmental neurobiology, to adult rat sensory neurons. With some key modifications, and selection of subtypes of neurons likely to respond to a purported growth factor, short-term responses to molecular gradients can be analyzed using routine dorsal root ganglion neuronal cell culture techniques. The caveats are that short-term turning does not necessarily reflect on the overall tropic impact of a molecule, particularly if it alters growth cones through intra-axonal translation. Similarly, to understand the trajectory of an axon, it must be in a growth mode, such as that associated with preconditioning from previous injury.
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Abstract
During development, production of neurons from neural stem cells, migration of neurons from their birthplace to their final location, and extension of neurites, axons, and dendrites are important for the formation of functional neuronal circuits. The actin cytoskeleton has major roles in the morphological development of neurons. In this chapter, we focused on the distribution and function of the actin-binding protein, drebrin, to elucidate the importance of drebrin-bound F-actin in neurons during early developmental stages of neurons in embryonic, postnatal, and adult brains. There are three major isoforms of drebrin in the chicken brain (E1, E2, and A) and two major isoforms in the mammalian brain (E and A). Among these drebrin isoforms, drebrin E1 and E2 in chicken and drebrin E in the mammalian brain are involved in these neuronal stages. In migrating neurons of the developing and adult brain, drebrin is localized at the base of filopodia of leading processes, to regulate neuronal migration. In axonal growth cones, drebrin is localized in the transitional zone to regulate axonal growth by inhibiting actomyosin interactions and mediating the interactions between F-actin and microtubules. For axonal collateral branching, drebrin is localized at axonal actin patches and the base of filopodia, to accelerate the transition from actin patches to filopodia and stabilize the filopodia.
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Herrera E, Erskine L, Morenilla-Palao C. Guidance of retinal axons in mammals. Semin Cell Dev Biol 2019; 85:48-59. [PMID: 29174916 DOI: 10.1016/j.semcdb.2017.11.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 11/21/2022]
Abstract
In order to navigate through the surrounding environment many mammals, including humans, primarily rely on vision. The eye, composed of the choroid, sclera, retinal pigmented epithelium, cornea, lens, iris and retina, is the structure that receives the light and converts it into electrical impulses. The retina contains six major types of neurons involving in receiving and modifying visual information and passing it onto higher visual processing centres in the brain. Visual information is relayed to the brain via the axons of retinal ganglion cells (RGCs), a projection known as the optic pathway. The proper formation of this pathway during development is essential for normal vision in the adult individual. Along this pathway there are several points where visual axons face 'choices' in their direction of growth. Understanding how these choices are made has advanced significantly our knowledge of axon guidance mechanisms. Thus, the development of the visual pathway has served as an extremely useful model to reveal general principles of axon pathfinding throughout the nervous system. However, due to its particularities, some cellular and molecular mechanisms are specific for the visual circuit. Here we review both general and specific mechanisms involved in the guidance of mammalian RGC axons when they are traveling from the retina to the brain to establish precise and stereotyped connections that will sustain vision.
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Borgen MA, Wang D, Grill B. RPM-1 regulates axon termination by affecting growth cone collapse and microtubule stability. Development 2017; 144:4658-4672. [PMID: 29084805 DOI: 10.1242/dev.154187] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 10/21/2017] [Indexed: 12/14/2022]
Abstract
Axon termination is essential for efficient and accurate nervous system construction. At present, relatively little is known about how growth cone collapse occurs prior to axon termination in vivo Using the mechanosensory neurons of C. elegans, we found collapse prior to axon termination is protracted, with the growth cone transitioning from a dynamic to a static state. Growth cone collapse prior to termination is facilitated by the signaling hub RPM-1. Given the prominence of the cytoskeleton in growth cone collapse, we assessed the relationship between RPM-1 and regulators of actin dynamics and microtubule stability. Our results reveal several important findings about how axon termination is orchestrated: (1) RPM-1 functions in parallel to RHO-1 and CRMP/UNC-33, but is suppressed by the Rac isoform MIG-2; (2) RPM-1 opposes the function of microtubule stabilizers, including tubulin acetyltransferases; and (3) genetic epistasis suggests the microtubule-stabilizing protein Tau/PTL-1 potentially inhibits RPM-1. These findings provide insight into how growth cone collapse is regulated during axon termination in vivo, and suggest that RPM-1 signaling destabilizes microtubules to facilitate growth cone collapse and axon termination.
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Affiliation(s)
- Melissa A Borgen
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
| | - Dandan Wang
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
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Gasperini RJ, Pavez M, Thompson AC, Mitchell CB, Hardy H, Young KM, Chilton JK, Foa L. How does calcium interact with the cytoskeleton to regulate growth cone motility during axon pathfinding? Mol Cell Neurosci 2017; 84:29-35. [PMID: 28765051 DOI: 10.1016/j.mcn.2017.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 02/04/2023] Open
Abstract
The precision with which neurons form connections is crucial for the normal development and function of the nervous system. The development of neuronal circuitry in the nervous system is accomplished by axon pathfinding: a process where growth cones guide axons through the embryonic environment to connect with their appropriate synaptic partners to form functional circuits. Despite intense efforts over many years to understand how this process is regulated, the complete repertoire of molecular mechanisms that govern the growth cone cytoskeleton and hence motility, remain unresolved. A central tenet in the axon guidance field is that calcium signals regulate growth cone behaviours such as extension, turning and pausing by regulating rearrangements of the growth cone cytoskeleton. Here, we provide evidence that not only the amplitude of a calcium signal is critical for growth cone motility but also the source of calcium mobilisation. We provide an example of this idea by demonstrating that manipulation of calcium signalling via L-type voltage gated calcium channels can perturb sensory neuron motility towards a source of netrin-1. Understanding how calcium signals can be transduced to initiate cytoskeletal changes represents a significant gap in our current knowledge of the mechanisms that govern axon guidance, and consequently the formation of functional neural circuits in the developing nervous system.
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Affiliation(s)
- Robert J Gasperini
- School of Medicine, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | - Macarena Pavez
- School of Medicine, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | - Adrian C Thompson
- School of Medicine, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | - Camilla B Mitchell
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | - Holly Hardy
- University of Exeter Medical School, Wellcome Wolfson Centre for Medical Research, Exeter EX2 5DW, United Kingdom.
| | - Kaylene M Young
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania 7001, Australia.
| | - John K Chilton
- University of Exeter Medical School, Wellcome Wolfson Centre for Medical Research, Exeter EX2 5DW, United Kingdom.
| | - Lisa Foa
- School of Medicine, University of Tasmania, Hobart, Tasmania 7001, Australia.
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Szikora S, Földi I, Tóth K, Migh E, Vig A, Bugyi B, Maléth J, Hegyi P, Kaltenecker P, Sanchez-Soriano N, Mihály J. The formin DAAM is required for coordination of the actin and microtubule cytoskeleton in axonal growth cones. J Cell Sci 2017; 130:2506-2519. [PMID: 28606990 DOI: 10.1242/jcs.203455] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/05/2017] [Indexed: 01/10/2023] Open
Abstract
Directed axonal growth depends on correct coordination of the actin and microtubule cytoskeleton in the growth cone. However, despite the relatively large number of proteins implicated in actin-microtubule crosstalk, the mechanisms whereby actin polymerization is coupled to microtubule stabilization and advancement in the peripheral growth cone remained largely unclear. Here, we identified the formin Dishevelled-associated activator of morphogenesis (DAAM) as a novel factor playing a role in concerted regulation of actin and microtubule remodeling in Drosophilamelanogaster primary neurons. In vitro, DAAM binds to F-actin as well as to microtubules and has the ability to crosslink the two filament systems. Accordingly, DAAM associates with the neuronal cytoskeleton, and a significant fraction of DAAM accumulates at places where the actin filaments overlap with that of microtubules. Loss of DAAM affects growth cone and microtubule morphology, and several aspects of microtubule dynamics; and biochemical and cellular assays revealed a microtubule stabilization activity and binding to the microtubule tip protein EB1. Together, these data suggest that, besides operating as an actin assembly factor, DAAM is involved in linking actin remodeling in filopodia to microtubule stabilization during axonal growth.
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Affiliation(s)
- Szilárd Szikora
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, MTA-SZBK NAP B Axon Growth and Regeneration Group, Temesvári krt. 62, Szeged H-6726, Hungary
| | - István Földi
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, MTA-SZBK NAP B Axon Growth and Regeneration Group, Temesvári krt. 62, Szeged H-6726, Hungary
| | - Krisztina Tóth
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, MTA-SZBK NAP B Axon Growth and Regeneration Group, Temesvári krt. 62, Szeged H-6726, Hungary
| | - Ede Migh
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, MTA-SZBK NAP B Axon Growth and Regeneration Group, Temesvári krt. 62, Szeged H-6726, Hungary
| | - Andrea Vig
- University of Pécs, Medical School, Department of Biophysics, Szigeti str. 12, Pécs H-7624, Hungary
| | - Beáta Bugyi
- University of Pécs, Medical School, Department of Biophysics, Szigeti str. 12, Pécs H-7624, Hungary.,Szentágothai Research Center, Ifjúság str. 34, Pécs H-7624, Hungary
| | - József Maléth
- MTA-SZTE Translational Gastroenterology Research Group, First Department of Internal Medicine, Szeged H-6720, Hungary
| | - Péter Hegyi
- MTA-SZTE Translational Gastroenterology Research Group, First Department of Internal Medicine, Szeged H-6720, Hungary.,Institute for Translational Medicine, Department of Pathophysiology, University of Pécs, Pécs H-7624, Hungary
| | - Péter Kaltenecker
- Institute for Translational Medicine, Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK
| | - Natalia Sanchez-Soriano
- Institute for Translational Medicine, Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK
| | - József Mihály
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, MTA-SZBK NAP B Axon Growth and Regeneration Group, Temesvári krt. 62, Szeged H-6726, Hungary
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40
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Erdogan B, Cammarata GM, Lee EJ, Pratt BC, Francl AF, Rutherford EL, Lowery LA. The microtubule plus-end-tracking protein TACC3 promotes persistent axon outgrowth and mediates responses to axon guidance signals during development. Neural Dev 2017; 12:3. [PMID: 28202041 PMCID: PMC5312526 DOI: 10.1186/s13064-017-0080-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 02/06/2017] [Indexed: 12/14/2022] Open
Abstract
Background Formation of precise neuronal connections requires proper axon guidance. Microtubules (MTs) of the growth cone provide a critical driving force during navigation of the growing ends of axons. Pioneer MTs and their plus-end tracking proteins (+TIPs) are thought to play integrative roles during this navigation. TACC3 is a + TIP that we have previously implicated in regulating MT dynamics within axons. However, the role of TACC3 in axon guidance has not been previously explored. Results Here, we show that TACC3 is required to promote persistent axon outgrowth and prevent spontaneous axon retractions in embryonic Xenopus laevis neurons. We also show that overexpressing TACC3 can counteract the depolymerizing effect of low doses of nocodazole, and that TACC3 interacts with MT polymerase XMAP215 to promote axon outgrowth. Moreover, we demonstrate that manipulation of TACC3 levels interferes with the growth cone response to the axon guidance cue Slit2 ex vivo, and that ablation of TACC3 causes pathfinding defects in axons of developing spinal neurons in vivo. Conclusion Together, our results suggest that by mediating MT dynamics, the + TIP TACC3 is involved in axon outgrowth and pathfinding decisions of neurons during embryonic development.
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Affiliation(s)
- Burcu Erdogan
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | | | - Eric J Lee
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Benjamin C Pratt
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Andrew F Francl
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Erin L Rutherford
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA.
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Itofusa R, Tojima T, Kamiguchi H. Visualization of Clathrin-Mediated Endocytosis During Semaphorin-Guided Axonal Growth. Methods Mol Biol 2017; 1493:287-298. [PMID: 27787859 DOI: 10.1007/978-1-4939-6448-2_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Semaphorin3A (Sema3A) guides axonal growth during neuronal network development. Accumulating evidence indicates that Sema3A-induced growth cone collapse and repulsion involve endocytic membrane trafficking in the growth cone. It is now possible to visualize endocytic processes in living cells using total internal reflection fluorescence microscopy (TIRFM), a powerful tool for imaging dynamic subcellular events at the plasma membrane. In this chapter, we describe a method for TIRFM observation and analysis of clathrin-mediated endocytosis in growth cones of chicken dorsal root ganglion neurons that receive an extracellular concentration gradient of Sema3A in a culture medium.
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Affiliation(s)
- Rurika Itofusa
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Takuro Tojima
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Hiroyuki Kamiguchi
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
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Abstract
Neuritogenesis is an early event in neuronal development in which newborn neurons first form growth cones, as a prerequisite for the formation of axons and dendrites. Growth cones emerge from segmented regions of the lamellipodium of embryonic neurons and grow away from the cell body leaving behind a neurite that will eventually polarise into an axon or dendrite. Growth cones also function to navigate precise routes through the embryo to locate an appropriate synaptic partner. Dynamic interactions between two components of the neuronal cytoskeleton, actin filaments and microtubules, are known to be essential for growth cone formation and hence neuritogenesis. The molecular mechanisms that coordinate interactions between actin filaments and dynamic microtubules during neuritogenesis are beginning to be understood. One candidate pathway coupling actin filaments to microtubules consists of the actin filament-binding protein drebrin and the microtubule-binding +TIP protein EB3. This pathway is regulated proximally by cyclin-dependent kinase 5 phosphorylation of drebrin but the upstream elements in the pathway have yet to be identified.
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Valek L, Häussler A, Dröse S, Eaton P, Schröder K, Tegeder I. Redox-guided axonal regrowth requires cyclic GMP dependent protein kinase 1: Implication for neuropathic pain. Redox Biol 2016; 11:176-191. [PMID: 27978504 PMCID: PMC5156608 DOI: 10.1016/j.redox.2016.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/03/2016] [Accepted: 12/02/2016] [Indexed: 01/27/2023] Open
Abstract
Cyclic GMP-dependent protein kinase 1 (PKG1) mediates presynaptic nociceptive long-term potentiation (LTP) in the spinal cord and contributes to inflammatory pain in rodents but the present study revealed opposite effects in the context of neuropathic pain. We used a set of loss-of-function models for in vivo and in vitro studies to address this controversy: peripheral neuron specific deletion (SNS-PKG1-/-), inducible deletion in subsets of neurons (SLICK-PKG1-/-) and redox-dead PKG1 mutants. In contrast to inflammatory pain, SNS-PKG1-/- mice developed stronger neuropathic hyperalgesia associated with an impairment of nerve regeneration, suggesting specific repair functions of PKG1. Although PKG1 accumulated at the site of injury, its activity was lost in the proximal nerve due to a reduction of oxidation-dependent dimerization, which was a consequence of mitochondrial damage in injured axons. In vitro, PKG1 deficiency or its redox-insensitivity resulted in enhanced outgrowth and reduction of growth cone collapse in response to redox signals, which presented as oxidative hotspots in growing cones. At the molecular level, PKG1 deficiency caused a depletion of phosphorylated cofilin, which is essential for growth cone collapse and guidance. Hence, redox-mediated guidance required PKG1 and consequently, its deficiency in vivo resulted in defective repair and enhanced neuropathic pain after nerve injury. PKG1-dependent repair functions will outweigh its signaling functions in spinal nociceptive LTP, so that inhibition of PKG1 is no option for neuropathic pain. Axonal injury leads mitochondrial damage. The loss of signaling ROS is associated with a reduction of redox-dependent autoactivation of PKG1. Loss of PKG1 impairs peripheral nerve regeneration and aggravates neuropathic pain in mice. Oxidative hot spots are generated in spiky growth cones and trigger growth cone collapse via PKG1. Malfunctioning of this redox-PKG1 guided growth cone collapse leads to aberrant outgrowth.
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Affiliation(s)
- Lucie Valek
- Depts. of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Annett Häussler
- Depts. of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Stefan Dröse
- Depts. of Anaesthesiology, Goethe-University Hospital, Frankfurt, Germany
| | - Philipp Eaton
- King's College of London, Cardiovascular Division, The Rayne Institute, St. Thomas' Hospital, London, United Kingdom
| | - Katrin Schröder
- Depts. of Cardiovascular Physiology, Goethe-University Hospital, Frankfurt, Germany
| | - Irmgard Tegeder
- Depts. of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany.
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Goshima Y, Takei K. Micro-CALI to Study Localized Roles of the Semaphorin Signaling Component CRMP in Axon Growth. Methods Mol Biol 2017; 1493:265-75. [PMID: 27787857 DOI: 10.1007/978-1-4939-6448-2_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Elucidating the local function of proteins is essential for understanding not only the individual proteins but also the organization of the cell or even tissue as a whole. However, until now, few attempts have been made to understand local proteins function in cells because of a lack of acute inactivation technique of local proteins with high versatility. Here we describe the application of the chromophore-assisted light inactivation (CALI) method to elucidate the role of the semaphorin signaling component CRMP located within the growth cone area in axon growth and growth cone turning.
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45
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Pacheco A, Gallo G. Actin filament-microtubule interactions in axon initiation and branching. Brain Res Bull 2016; 126:300-310. [PMID: 27491623 DOI: 10.1016/j.brainresbull.2016.07.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/28/2016] [Accepted: 07/30/2016] [Indexed: 10/21/2022]
Abstract
Neurons begin life as spherical cells. A major hallmark of neuronal development is the formation of elongating processes from the cell body which subsequently differentiate into dendrites and the axon. The formation and later development of neuronal processes is achieved through the concerted organization of actin filaments and microtubules. Here, we review the literature regarding recent advances in the understanding of cytoskeletal interactions in neurons focusing on the initiation of processes from neuronal cell bodies and the collateral branching of axons. The complex crosstalk between cytoskeletal elements is mediated by a cohort of proteins that either bind both cytoskeletal systems or allow one to regulate the other. Recent studies have highlighted the importance of microtubule plus-tip proteins in the regulation of the dynamics and organization of actin filaments, while also providing a mechanism for the subcellular capture and guidance of microtubule tips by actin filaments. Although the understanding of cytoskeletal crosstalk and interactions in neuronal morphogenesis has advanced significantly in recent years the appreciation of the neuron as an integrated cytoskeletal system remains a frontier.
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Affiliation(s)
- Almudena Pacheco
- Temple University, Lewis Kats School of Medicine, Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, 3500 North Broad Street, Philadelphia, PA 19140, United States
| | - Gianluca Gallo
- Temple University, Lewis Kats School of Medicine, Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, 3500 North Broad Street, Philadelphia, PA 19140, United States.
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Davidson JM, Wong CT, Rai-Bhogal R, Li H, Crawford DA. Prostaglandin E2 elevates calcium in differentiated neuroectodermal stem cells. Mol Cell Neurosci 2016; 74:71-7. [PMID: 27074429 DOI: 10.1016/j.mcn.2016.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 03/21/2016] [Accepted: 03/31/2016] [Indexed: 01/02/2023] Open
Abstract
Lipid mediator prostaglandin E2 (PGE2) is an endogenous signaling molecule that plays an important role during early development of the nervous system. Abnormalities in the PGE2 signaling pathway have been associated with neurodevelopmental disorders such as autism spectrum disorders. In this study we use ratiometric fura-2AM calcium imaging to show that higher levels of PGE2 elevate intracellular calcium levels in the cell soma and growth cones of differentiated neuroectodermal (NE-4C) stem cells. PGE2 also increased the amplitude of calcium fluctuation in the neuronal growth cones and affected the neurite extension length. In summary, our results show that PGE2 may adversely impact intracellular calcium dynamics in differentiated neuronal cells and possibly affect early development of the nervous system.
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Affiliation(s)
- Jennilee M Davidson
- Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Christine T Wong
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada
| | - Ravneet Rai-Bhogal
- Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Hongyan Li
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada
| | - Dorota A Crawford
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
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47
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Flamm AG, Żerko S, Zawadzka-Kazimierczuk A, Koźmiński W, Konrat R, Coudevylle N. 1H, 15N, 13C resonance assignment of human GAP-43. Biomol NMR Assign 2016; 10:171-174. [PMID: 26748655 PMCID: PMC4788685 DOI: 10.1007/s12104-015-9660-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/28/2015] [Indexed: 05/31/2023]
Abstract
GAP-43 is a 25 kDa neuronal intrinsically disordered protein, highly abundant in the neuronal growth cone during development and regeneration. The exact molecular function(s) of GAP-43 remains unclear but it appears to be involved in growth cone guidance and actin cytoskeleton organization. Therefore, GAP-43 seems to play an important role in neurotransmitter vesicle fusion and recycling, long-term potentiation, spatial memory formation and learning. Here we report the nearly complete assignment of recombinant human GAP-43.
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Affiliation(s)
- Andrea Gabriele Flamm
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Szymon Żerko
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Anna Zawadzka-Kazimierczuk
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Wiktor Koźmiński
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Robert Konrat
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Nicolas Coudevylle
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
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Anastasiadou S, Knöll B. The multiple sclerosis drug fingolimod (FTY720) stimulates neuronal gene expression, axonal growth and regeneration. Exp Neurol 2016; 279:243-260. [PMID: 26980486 DOI: 10.1016/j.expneurol.2016.03.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 03/03/2016] [Accepted: 03/11/2016] [Indexed: 11/30/2022]
Abstract
Fingolimod (FTY720) is a new generation oral treatment for multiple sclerosis (MS). So far, FTY720 was mainly considered to target trafficking of immune cells but not brain cells such as neurons. Herein, we analyzed FTY720's potential to directly alter neuronal function. In CNS neurons, we identified a FTY720 governed gene expression response. FTY720 upregulated immediate early genes (IEGs) encoding for neuronal activity associated transcription factors such as c-Fos, FosB, Egr1 and Egr2 and induced actin cytoskeleton associated genes (actin isoforms, tropomyosin, calponin). Stimulation of primary neurons with FTY720 enhanced neurite growth and altered growth cone morphology. In accordance, FTY720 enhanced axon regeneration in mice upon facial nerve axotomy. We identified components of a FTY720 engaged signaling cascade including S1P receptors, G12/13G-proteins, RhoA-GTPases and the transcription factors SRF/MRTF. In summary, we uncovered a broader cellular and therapeutic operation mode of FTY720, suggesting beneficial FTY720 effects also on CNS neurons during MS therapy and for treatment of other neurodegenerative diseases requiring neuroprotective and neurorestorative processes.
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Affiliation(s)
- Sofia Anastasiadou
- Institute of Physiological Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Bernd Knöll
- Institute of Physiological Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
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49
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Erdogan B, Ebbert PT, Lowery LA. Using Xenopus laevis retinal and spinal neurons to study mechanisms of axon guidance in vivo and in vitro. Semin Cell Dev Biol 2016; 51:64-72. [PMID: 26853934 DOI: 10.1016/j.semcdb.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/01/2016] [Indexed: 11/26/2022]
Abstract
The intricate and precise establishment of neuronal connections in the developing nervous system relies on accurate navigation of growing axons. Since Ramón y Cajal's discovery of the growth cone, the phenomenon of axon guidance has been revealed as a coordinated operation of guidance molecules, receptors, secondary messengers, and responses driven by the dynamic cytoskeleton within the growth cone. With the advent of new and accelerating techniques, Xenopus laevis emerged as a robust model to investigate neuronal circuit formation during development. We present here the advantages of the Xenopus nervous system to our growing understanding of axon guidance.
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Affiliation(s)
- Burcu Erdogan
- Department of Biology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA.
| | - Patrick T Ebbert
- Department of Biology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA.
| | - Laura Anne Lowery
- Department of Biology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA.
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50
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Sahasrabudhe A, Ghate K, Mutalik S, Jacob A, Ghose A. Formin 2 regulates the stabilization of filopodial tip adhesions in growth cones and affects neuronal outgrowth and pathfinding in vivo. Development 2015; 143:449-60. [PMID: 26718007 DOI: 10.1242/dev.130104] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/23/2015] [Indexed: 12/28/2022]
Abstract
Growth cone filopodia are actin-based mechanosensory structures that are essential for chemoreception and the generation of contractile forces necessary for directional motility. However, little is known about the influence of filopodial actin structures on substrate adhesion and filopodial contractility. Formin 2 (Fmn2) localizes along filopodial actin bundles and its depletion does not affect filopodia initiation or elongation. However, Fmn2 activity is required for filopodial tip adhesion maturation and the ability of filopodia to generate traction forces. Dysregulation of filopodia in Fmn2-depleted neurons leads to compromised growth cone motility. Additionally, in mouse fibroblasts, Fmn2 regulates ventral stress fiber assembly and affects the stability of focal adhesions. In the developing chick spinal cord, Fmn2 activity is required cell-autonomously for the outgrowth and pathfinding of spinal commissural neurons. Our results reveal an unanticipated function for Fmn2 in neural development. Fmn2 regulates structurally diverse bundled actin structures, parallel filopodial bundles in growth cones and anti-parallel stress fibers in fibroblasts, in turn modulating the stability of substrate adhesions. We propose Fmn2 as a mediator of actin bundle integrity, enabling efficient force transmission to the adhesion sites.
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Affiliation(s)
- Abhishek Sahasrabudhe
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Ketakee Ghate
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Sampada Mutalik
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Ajesh Jacob
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Aurnab Ghose
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
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