1
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Areti A, Komirishetty P, Zochodne DW. Collaborative Roles for RAC1, ERM Proteins and PTEN During Adult Sensory Axon Regeneration. Mol Neurobiol 2024:10.1007/s12035-024-04273-7. [PMID: 38904854 DOI: 10.1007/s12035-024-04273-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024]
Abstract
The role of local of growth cone (GC) manipulation in adult regenerative systems is largely unexplored despite substantial translational importance. Here we investigated collaboration among Rac1 GTPase, its partnering ERM proteins and PTEN in adult sensory neurons and adult nerve regeneration. We confirmed expression of both Rac1 and ERM in adults and noted substantial impacts on neurite outgrowth in naïve and pre-injured adult sensory neurons. PTEN inhibition added to this outgrowth. Rac1 activation acted directly on adult GCs facilitating both attractive turning and advancement. In vivo regeneration indices including electrophysiological recovery, return of sensation, walking, repopulation of myelinated axons and reinnervation of the target epidermis indicated benefits of local Rac1 activation. These indices suggested maximal GC activation whereas local PTEN inhibition offered only limited added improvement. Our findings provide support for the concept of manipulating adult GCs, by emphasizing local Rac1 activation in directing therapy for nerve repair.
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Affiliation(s)
- Aparna Areti
- Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, 7-132 Clinical Sciences Building 11350-83 Ave, T6G 2G3, Edmonton, AB, Canada
| | - Prashanth Komirishetty
- Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, 7-132 Clinical Sciences Building 11350-83 Ave, T6G 2G3, Edmonton, AB, Canada
| | - Douglas W Zochodne
- Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, 7-132 Clinical Sciences Building 11350-83 Ave, T6G 2G3, Edmonton, AB, Canada.
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2
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Qiu Z, Minegishi T, Aoki D, Abe K, Baba K, Inagaki N. Adhesion-clutch between DCC and netrin-1 mediates netrin-1-induced axonal haptotaxis. Front Mol Neurosci 2024; 17:1307755. [PMID: 38375502 PMCID: PMC10875621 DOI: 10.3389/fnmol.2024.1307755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/08/2024] [Indexed: 02/21/2024] Open
Abstract
The growth cone, a motile structure located at the tip of growing axons, senses extracellular guidance cues and translates them into directional forces that drive axon outgrowth and guidance. Axon guidance directed by chemical cues on the extracellular adhesive substrate is termed haptotaxis. Recent studies reported that netrin-1 on the substrate functions as a haptotactic axon guidance cue. However, the mechanism mediating netrin-1-induced axonal haptotaxis remains unclear. Here, we demonstrate that substrate-bound netrin-1 induces axonal haptotaxis by facilitating physical interactions between the netrin-1 receptor, DCC, and the adhesive substrates. DCC serves as an adhesion receptor for netrin-1. The clutch-linker molecule shootin1a interacted with DCC, linking it to actin filament retrograde flow at the growth cone. Speckle imaging analyses showed that DCC underwent either grip (stop) or retrograde slip on the adhesive substrate. The grip state was more prevalent on netrin-1-coated substrate compared to the control substrate polylysine, thereby transmitting larger traction force on the netrin-1-coated substrate. Furthermore, disruption of the linkage between actin filament retrograde flow and DCC by shootin1 knockout impaired netrin-1-induced axonal haptotaxis. These results suggest that the directional force for netrin-1-induced haptotaxis is exerted on the substrates through the adhesion-clutch between DCC and netrin-1 which occurs asymmetrically within the growth cone.
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Affiliation(s)
| | | | | | | | | | - Naoyuki Inagaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
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3
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Qi J, Tan F, Zhang L, Zhou Y, Zhang Z, Sun Q, Li N, Fang Y, Chen X, Wu Y, Zhong G, Chai R. Critical role of TPRN rings in the stereocilia for hearing. Mol Ther 2024; 32:204-217. [PMID: 37952086 PMCID: PMC10787140 DOI: 10.1016/j.ymthe.2023.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 09/29/2023] [Accepted: 11/09/2023] [Indexed: 11/14/2023] Open
Abstract
Inner ear hair cells detect sound vibration through the deflection of mechanosensory stereocilia. Cytoplasmic protein TPRN has been shown to localize at the taper region of the stereocilia, and mutations in TPRN cause hereditary hearing loss through an unknown mechanism. Here, using biochemistry and dual stimulated emission depletion microscopy imaging, we show that the TPRN, together with its binding proteins CLIC5 and PTPRQ, forms concentric rings in the taper region of stereocilia. The disruption of TPRN rings, triggered by the competitive inhibition of the interaction of TPRN and CLIC5 or exogenous TPRN overexpression, leads to stereocilia degeneration and severe hearing loss. Most importantly, restoration of the TPRN rings can rescue the damaged auditory function of Tprn knockout mice by exogenously expressing TPRN at an appropriate level in HCs via promoter recombinant adeno-associated virus (AAV). In summary, our results reveal highly structured TPRN rings near the taper region of stereocilia that are crucial for stereocilia function and hearing. Also, TPRN ring restoration in stereocilia by AAV-Tprn effectively repairs damaged hearing, which lays the foundation for the clinical application of AAV-mediated gene therapy in patients with TPRN mutation.
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Affiliation(s)
- Jieyu Qi
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China; School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
| | - Fangzhi Tan
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China.
| | - Liyan Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Yinyi Zhou
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Ziyu Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Qiuhan Sun
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Nianci Li
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Yuan Fang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Xin Chen
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Yunhao Wu
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Guisheng Zhong
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - Renjie Chai
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China; School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 610072, China; Southeast University Shenzhen Research Institute, Shenzhen 518063, China.
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4
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Frost B. Alzheimer's disease and related tauopathies: disorders of disrupted neuronal identity. Trends Neurosci 2023; 46:797-813. [PMID: 37591720 PMCID: PMC10528597 DOI: 10.1016/j.tins.2023.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/20/2023] [Accepted: 07/24/2023] [Indexed: 08/19/2023]
Abstract
Postmitotic neurons require persistently active controls to maintain terminal differentiation. Unlike dividing cells, aberrant cell cycle activation in mature neurons causes apoptosis rather than transformation. In Alzheimer's disease (AD) and related tauopathies, evidence suggests that pathogenic forms of tau drive neurodegeneration via neuronal cell cycle re-entry. Multiple interconnected mechanisms linking tau to cell cycle activation have been identified, including, but not limited to, tau-induced overstabilization of the actin cytoskeleton, consequent changes to nuclear architecture, and disruption of heterochromatin-mediated gene silencing. Cancer- and development-associated pathways are upregulated in human and cellular models of tauopathy, and many tau-induced cellular phenotypes are also present in various cancers and progenitor/stem cells. In this review, I delve into mechanistic parallels between tauopathies, cancer, and development, and highlight the role of tau in cancer and in the developing brain. Based on these studies, I put forth a model by which pathogenic forms of tau disrupt the program that maintains terminal neuronal differentiation, driving cell cycle re-entry and consequent neuronal death. This framework presents tauopathies as conditions involving the profound toxic disruption of neuronal identity.
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Affiliation(s)
- Bess Frost
- Sam & Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
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5
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Barshtein G, Gural A, Arbell D, Barkan R, Livshits L, Pajic-Lijakovic I, Yedgar S. Red Blood Cell Deformability Is Expressed by a Set of Interrelated Membrane Proteins. Int J Mol Sci 2023; 24:12755. [PMID: 37628935 PMCID: PMC10454903 DOI: 10.3390/ijms241612755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Red blood cell (RBC) deformability, expressing their ability to change their shape, allows them to minimize their resistance to flow and optimize oxygen delivery to the tissues. RBC with reduced deformability may lead to increased vascular resistance, capillary occlusion, and impaired perfusion and oxygen delivery. A reduction in deformability, as occurs during RBC physiological aging and under blood storage, is implicated in the pathophysiology of diverse conditions with circulatory disorders and anemias. The change in RBC deformability is associated with metabolic and structural alterations, mostly uncharacterized. To bridge this gap, we analyzed the membrane protein levels, using mass spectroscopy, of RBC with varying deformability determined by image analysis. In total, 752 membrane proteins were identified. However, deformability was positively correlated with the level of only fourteen proteins, with a highly significant inter-correlation between them. These proteins are involved in membrane rafting and/or the membrane-cytoskeleton linkage. These findings suggest that the reduction of deformability is a programmed (not arbitrary) process of remodeling and shedding of membrane fragments, possibly mirroring the formation of extracellular vesicles. The highly significant inter-correlation between the deformability-expressing proteins infers that the cell deformability can be assessed by determining the level of a few, possibly one, of them.
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Affiliation(s)
- Gregory Barshtein
- Department of Biochemistry, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel;
| | - Alexander Gural
- Blood Bank, Hadassah University Hospital, Jerusalem 9112001, Israel;
| | - Dan Arbell
- Pediatric Surgery, Hadassah University Hospital, Jerusalem 9112001, Israel;
| | - Refael Barkan
- Department of Digital Medical Technologies, Holon Institute of Technology, Holon 5810201, Israel;
| | - Leonid Livshits
- Red Blood Cell Research Group, Vetsuisse Faculty, Institute of Veterinary Physiology, University of Zurich, 8057 Zürich, Switzerland;
| | | | - Saul Yedgar
- Department of Biochemistry, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel;
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6
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Safarians G, Sohrabi A, Solomon I, Xiao W, Bastola S, Rajput BW, Epperson M, Rosenzweig I, Tamura K, Singer B, Huang J, Harrison MJ, Sanazzaro T, Condro MC, Kornblum HI, Seidlits SK. Glioblastoma Spheroid Invasion through Soft, Brain-Like Matrices Depends on Hyaluronic Acid-CD44 Interactions. Adv Healthc Mater 2023:e2203143. [PMID: 36694362 DOI: 10.1002/adhm.202203143] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Indexed: 01/26/2023]
Abstract
Increased secretion of hyaluronic acid (HA), a glycosaminoglycan abundant in the brain extracellular matrix (ECM), correlates with worse clinical outcomes for glioblastoma (GBM) patients. GBM cells aggressively invade the brain parenchyma while encountering spatiotemporal changes in their local ECM, including HA concentration. To investigate how varying HA concentrations affect GBM invasion, patient-derived GBM cells are cultured within a soft, 3D matrix in which HA concentration is precisely varied and cell migration observed. Data demonstrate that HA concentration can determine the invasive activity of patient-derived GBM cells in a biphasic and highly sensitive manner, where the absolute concentration of HA at which cell migration peaked is specific to each patient-derived line. Furthermore, evidence that this response relies on phosphorylated ezrin, which interacts with the intracellular domain of HA-engaged CD44 to effectively link the actin cytoskeleton to the local ECM is provided. Overall, this study highlights CD44-HA binding as a major mediator of GBM cell migration that acts independently of integrins and focal adhesion complexes and suggests that targeting HA-CD44-ezrin interactions represents a promising therapeutic strategy to prevent tumor cell invasion in the brain.
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Affiliation(s)
- Gevick Safarians
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Alireza Sohrabi
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.,Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Itay Solomon
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Weikun Xiao
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Soniya Bastola
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.,Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Bushra W Rajput
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Mary Epperson
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Isabella Rosenzweig
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Kelly Tamura
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Breahna Singer
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Joyce Huang
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Mollie J Harrison
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Talia Sanazzaro
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Michael C Condro
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Harley I Kornblum
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Stephanie K Seidlits
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.,Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
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7
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Qu Y, Alves‐Silva J, Gupta K, Hahn I, Parkin J, Sánchez‐Soriano N, Prokop A. Re-evaluating the actin-dependence of spectraplakin functions during axon growth and maintenance. Dev Neurobiol 2022; 82:288-307. [PMID: 35333003 PMCID: PMC9320987 DOI: 10.1002/dneu.22873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/30/2022] [Accepted: 03/07/2022] [Indexed: 11/11/2022]
Abstract
Axons are the long and slender processes of neurons constituting the biological cables that wire the nervous system. The growth and maintenance of axons require loose microtubule bundles that extend through their entire length. Understanding microtubule regulation is therefore an essential aspect of axon biology. Key regulators of neuronal microtubules are the spectraplakins, a well-conserved family of cytoskeletal cross-linkers that underlie neuropathies in mouse and humans. Spectraplakin deficiency in mouse or Drosophila causes severe decay of microtubule bundles and reduced axon growth. The underlying mechanisms are best understood for Drosophila's spectraplakin Short stop (Shot) and believed to involve cytoskeletal cross-linkage: Shot's binding to microtubules and Eb1 via its C-terminus has been thoroughly investigated, whereas its F-actin interaction via N-terminal calponin homology (CH) domains is little understood. Here, we have gained new understanding by showing that the F-actin interaction must be finely balanced: altering the properties of F-actin networks or deleting/exchanging Shot's CH domains induces changes in Shot function-with a Lifeact-containing Shot variant causing remarkable remodeling of neuronal microtubules. In addition to actin-microtubule (MT) cross-linkage, we find strong indications that Shot executes redundant MT bundle-promoting roles that are F-actin-independent. We argue that these likely involve the neuronal Shot-PH isoform, which is characterized by a large, unexplored central plakin repeat region (PRR) similarly existing also in mammalian spectraplakins.
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Affiliation(s)
- Yue Qu
- Manchester Academic Health Science CentreFaculty of BiologyMedicine and HealthSchool of Biology, The University of ManchesterManchesterUK
- Present address:
Division of Nutritional Sciences, College of Human Ecology, Cornell University, Ithaca, USA
| | - Juliana Alves‐Silva
- Manchester Academic Health Science CentreFaculty of BiologyMedicine and HealthSchool of Biology, The University of ManchesterManchesterUK
- Present address:
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Kriti Gupta
- Department of Molecular Physiology & Cell SignallingInstitute of SystemsMolecular & Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Ines Hahn
- Manchester Academic Health Science CentreFaculty of BiologyMedicine and HealthSchool of Biology, The University of ManchesterManchesterUK
| | - Jill Parkin
- Manchester Academic Health Science CentreFaculty of BiologyMedicine and HealthSchool of Biology, The University of ManchesterManchesterUK
| | - Natalia Sánchez‐Soriano
- Department of Molecular Physiology & Cell SignallingInstitute of SystemsMolecular & Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Andreas Prokop
- Manchester Academic Health Science CentreFaculty of BiologyMedicine and HealthSchool of Biology, The University of ManchesterManchesterUK
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8
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Jung M, Kim D, Mun JY. Direct Visualization of Actin Filaments and Actin-Binding Proteins in Neuronal Cells. Front Cell Dev Biol 2020; 8:588556. [PMID: 33324645 PMCID: PMC7726226 DOI: 10.3389/fcell.2020.588556] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Abstract
Actin networks and actin-binding proteins (ABPs) are most abundant in the cytoskeleton of neurons. The function of ABPs in neurons is nucleation of actin polymerization, polymerization or depolymerization regulation, bundling of actin through crosslinking or stabilization, cargo movement along actin filaments, and anchoring of actin to other cellular components. In axons, ABP–actin interaction forms a dynamic, deep actin network, which regulates axon extension, guidance, axon branches, and synaptic structures. In dendrites, actin and ABPs are related to filopodia attenuation, spine formation, and synapse plasticity. ABP phosphorylation or mutation changes ABP–actin binding, which regulates axon or dendritic plasticity. In addition, hyperactive ABPs might also be expressed as aggregates of abnormal proteins in neurodegeneration. Those changes cause many neurological disorders. Here, we will review direct visualization of ABP and actin using various electron microscopy (EM) techniques, super resolution microscopy (SRM), and correlative light and electron microscopy (CLEM) with discussion of important ABPs in neuron.
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Affiliation(s)
- Minkyo Jung
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Doory Kim
- Department of Chemistry, Research Institute for Convergence of Basic Sciences, Institute of Nano Science and Technology, Research Institute for Natural Sciences, Hanyang University, Seoul, South Korea
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, South Korea
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9
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Synapse type-specific proteomic dissection identifies IgSF8 as a hippocampal CA3 microcircuit organizer. Nat Commun 2020; 11:5171. [PMID: 33057002 PMCID: PMC7560607 DOI: 10.1038/s41467-020-18956-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 09/23/2020] [Indexed: 12/20/2022] Open
Abstract
Excitatory and inhibitory neurons are connected into microcircuits that generate circuit output. Central in the hippocampal CA3 microcircuit is the mossy fiber (MF) synapse, which provides powerful direct excitatory input and indirect feedforward inhibition to CA3 pyramidal neurons. Here, we dissect its cell-surface protein (CSP) composition to discover novel regulators of MF synaptic connectivity. Proteomic profiling of isolated MF synaptosomes uncovers a rich CSP composition, including many CSPs without synaptic function and several that are uncharacterized. Cell-surface interactome screening identifies IgSF8 as a neuronal receptor enriched in the MF pathway. Presynaptic Igsf8 deletion impairs MF synaptic architecture and robustly decreases the density of bouton filopodia that provide feedforward inhibition. Consequently, IgSF8 loss impairs excitation/inhibition balance and increases excitability of CA3 pyramidal neurons. Our results provide insight into the CSP landscape and interactome of a specific excitatory synapse and reveal IgSF8 as a critical regulator of CA3 microcircuit connectivity and function. Mossy fiber synapses are key in CA3 microcircuit function. Here, the authors profile the mossy fiber synapse proteome and cell-surface interactome. They uncover a diverse repertoire of cell-surface proteins and identify the receptor IgSF8 as a regulator of CA3 microcircuit connectivity and function.
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10
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Much More Than a Scaffold: Cytoskeletal Proteins in Neurological Disorders. Cells 2020; 9:cells9020358. [PMID: 32033020 PMCID: PMC7072452 DOI: 10.3390/cells9020358] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023] Open
Abstract
Recent observations related to the structure of the cytoskeleton in neurons and novel cytoskeletal abnormalities involved in the pathophysiology of some neurological diseases are changing our view on the function of the cytoskeletal proteins in the nervous system. These efforts allow a better understanding of the molecular mechanisms underlying neurological diseases and allow us to see beyond our current knowledge for the development of new treatments. The neuronal cytoskeleton can be described as an organelle formed by the three-dimensional lattice of the three main families of filaments: actin filaments, microtubules, and neurofilaments. This organelle organizes well-defined structures within neurons (cell bodies and axons), which allow their proper development and function through life. Here, we will provide an overview of both the basic and novel concepts related to those cytoskeletal proteins, which are emerging as potential targets in the study of the pathophysiological mechanisms underlying neurological disorders.
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11
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Cicvaric A, Sachernegg HM, Stojanovic T, Symmank D, Smani T, Moeslinger T, Uhrin P, Monje FJ. Podoplanin Gene Disruption in Mice Promotes in vivo Neural Progenitor Cells Proliferation, Selectively Impairs Dentate Gyrus Synaptic Depression and Induces Anxiety-Like Behaviors. Front Cell Neurosci 2020; 13:561. [PMID: 32009902 PMCID: PMC6974453 DOI: 10.3389/fncel.2019.00561] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/05/2019] [Indexed: 12/20/2022] Open
Abstract
Podoplanin (Pdpn), a brain-tumor-related glycoprotein identified in humans and animals, is endogenously expressed in several organs critical for life support such as kidney, lung, heart and brain. In the brain, Pdpn has been identified in proliferative nestin-positive adult neural progenitor cells and in neurons of the neurogenic hippocampal dentate gyrus (DG), a structure associated to anxiety, critical for learning and memory functions and severely damaged in people with Alzheimer's Disease (AD). The in vivo role of Pdpn in adult neurogenesis and anxiety-like behavior remained however unexplored. Using mice with disrupted Pdpn gene as a model organism and applying combined behavioral, molecular biological and electrophysiological assays, we here show that the absence of Pdpn selectively impairs long-term synaptic depression in the neurogenic DG without affecting the CA3-Schaffer's collateral-CA1 synapses. Pdpn deletion also enhanced the proliferative capacity of DG neural progenitor cells and diminished survival of differentiated neuronal cells in vitro. In addition, mice with podoplanin gene disruption showed increased anxiety-like behaviors in experimentally validated behavioral tests as compared to wild type littermate controls. Together, these findings broaden our knowledge on the molecular mechanisms influencing hippocampal synaptic plasticity and neurogenesis in vivo and reveal Pdpn as a novel molecular target for future studies addressing general anxiety disorder and synaptic depression-related memory dysfunctions.
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Affiliation(s)
- Ana Cicvaric
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
| | - Hannah M. Sachernegg
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
| | - Tamara Stojanovic
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
| | - Dörte Symmank
- Center for Physiology and Pharmacology, Institute for Physiology, Medical University of Vienna, Vienna, Austria
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville (IBiS)/University of Seville/CIBERCV, Seville, Spain
| | - Thomas Moeslinger
- Center for Physiology and Pharmacology, Institute for Physiology, Medical University of Vienna, Vienna, Austria
| | - Pavel Uhrin
- Center for Physiology and Pharmacology, Department of Vascular Biology and Thrombosis Research, Medical University of Vienna, Vienna, Austria
| | - Francisco J. Monje
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
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12
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Chen CH, Hsu HW, Chang YH, Pan CL. Adhesive L1CAM-Robo Signaling Aligns Growth Cone F-Actin Dynamics to Promote Axon-Dendrite Fasciculation in C. elegans. Dev Cell 2019; 48:215-228.e5. [PMID: 30555000 DOI: 10.1016/j.devcel.2018.10.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/18/2018] [Accepted: 10/26/2018] [Indexed: 11/28/2022]
Abstract
Neurite fasciculation through contact-dependent signaling is important for the wiring and function of the neuronal circuits. Here, we describe a type of axon-dendrite fasciculation in C. elegans, where proximal dendrites of the nociceptor PVD adhere to the axon of the ALA interneuron. This axon-dendrite fasciculation is mediated by a previously uncharacterized adhesive signaling by the ALA membrane signal SAX-7/L1CAM and the PVD receptor SAX-3/Robo but independent of Slit. L1CAM physically interacts with Robo and instructs dendrite adhesion in a Robo-dependent manner. Fasciculation mediated by L1CAM-Robo signaling aligns F-actin dynamics in the dendrite growth cone and facilitates dynamic growth cone behaviors for efficient dendrite guidance. Disruption of PVD dendrite fasciculation impairs nociceptive mechanosensation and rhythmicity in body curvature, suggesting that dendrite fasciculation governs the functions of mechanosensory circuits. Our work elucidates the molecular mechanisms by which adhesive axon-dendrite signaling shapes the construction and function of sensory neuronal circuits.
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Affiliation(s)
- Chun-Hao Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No.7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Hao-Wei Hsu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No.7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Yun-Hsuan Chang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No.7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No.7 Chung-Shan South Road, Taipei 10002, Taiwan.
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13
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Hyperactivity of Rac1-GTPase pathway impairs neuritogenesis of cortical neurons by altering actin dynamics. Sci Rep 2018; 8:7254. [PMID: 29740022 PMCID: PMC5940682 DOI: 10.1038/s41598-018-25354-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/18/2018] [Indexed: 01/10/2023] Open
Abstract
The small-GTPase Rac1 is a key molecular regulator linking extracellular signals to actin cytoskeleton dynamics. Loss-of-function mutations in RAC1 and other genes of the Rac signaling pathway have been implicated in the pathogenesis of Intellectual Disability (ID). The Rac1 activity is negatively controlled by GAP proteins, however the effect of Rac1 hyperactivity on neuronal networking in vivo has been poorly studied. ArhGAP15 is a Rac-specific negative regulator, expressed in the main subtypes of pyramidal cortical neurons. In the absence of ArhGAP15, cortical pyramidal neurons show defective neuritogenesis, delayed axonal elongation, reduced dendritic branching, both in vitro and in vivo. These phenotypes are associated with altered actin dynamics at the growth cone due to increased activity of the PAK-LIMK pathway and hyperphosphorylation of ADF/cofilin. These results can be explained by shootin1 hypo-phosphorylation and uncoupling with the adhesion system. Functionally, ArhGAP15−/− mice exhibit decreased synaptic density, altered electroencephalographic rhythms and cognitive deficits. These data suggest that both hypo- and hyperactivation of the Rac pathway due to mutations in Rac1 regulators can result in conditions of ID, and that a tight regulation of Rac1 activity is required to attain the full complexity of the cortical networks.
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14
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Merino P, Diaz A, Manrique LG, Cheng L, Yepes M. Urokinase-type plasminogen activator (uPA) promotes ezrin-mediated reorganization of the synaptic cytoskeleton in the ischemic brain. J Biol Chem 2018; 293:9234-9247. [PMID: 29720403 DOI: 10.1074/jbc.ra118.002534] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/30/2018] [Indexed: 11/06/2022] Open
Abstract
Synaptic repair in the ischemic brain is a complex process that requires reorganization of the actin cytoskeleton. Ezrin, radixin, and moesin (ERM) are a group of evolutionarily conserved proteins that link the plasma membrane to the actin cytoskeleton and act as scaffolds for signaling transduction. Urokinase-type plasminogen activator (uPA) is a serine proteinase that upon binding to the urokinase-type plasminogen activator receptor (uPAR) catalyzes the conversion of plasminogen into plasmin on the cell surface and activates intracellular signaling pathways. Early studies indicate that uPA and uPAR expression increase during the recovery phase from an ischemic stroke and that uPA binding to uPAR promotes neurorepair in the ischemic brain. The in vitro and in vivo studies presented here show that either the release of neuronal uPA or treatment with recombinant uPA induces the local synthesis of ezrin in the synapse and the recruitment of β3-integrin to the postsynaptic density (PSD) of cerebral cortical neurons by a plasminogen-independent mechanism. We found that β3-integrin has a double effect on ezrin, inducing its recruitment to the PSD via the intercellular adhesion molecule-5 (ICAM-5) and its subsequent activation by phosphorylation at Thr-567. Finally, our data indicate that by triggering the reorganization of the actin cytoskeleton in the postsynaptic terminal, active ezrin induces the recovery of dendritic spines and synapses that have been damaged by an acute ischemic stroke. In summary, our data show that uPA-uPAR binding promotes synaptic repair in the ischemic brain via ezrin-mediated reorganization of the actin cytoskeleton in the postsynaptic terminal.
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Affiliation(s)
- Paola Merino
- From the Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Atlanta, Georgia 30329.,the Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Ariel Diaz
- From the Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Atlanta, Georgia 30329.,the Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Luis Guillermo Manrique
- From the Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Atlanta, Georgia 30329.,the Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Lihong Cheng
- From the Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Atlanta, Georgia 30329.,the Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Manuel Yepes
- From the Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Atlanta, Georgia 30329, .,the Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322, and.,the Department of Neurology, Veterans Affairs Medical Center, Atlanta, Georgia 30033
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15
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Jin EJ, Ko HR, Hwang I, Kim BS, Choi JY, Park KW, Cho SW, Ahn JY. Akt regulates neurite growth by phosphorylation-dependent inhibition of radixin proteasomal degradation. Sci Rep 2018; 8:2557. [PMID: 29416050 PMCID: PMC5803261 DOI: 10.1038/s41598-018-20755-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/23/2018] [Indexed: 12/20/2022] Open
Abstract
Neurite growth is controlled by a complex molecular signaling network that regulates filamentous actin (F-actin) dynamics at the growth cone. The evolutionarily conserved ezrin, radixin, and moesin family of proteins tether F-actin to the cell membrane when phosphorylated at a conserved threonine residue and modulate neurite outgrowth. Here we show that Akt binds to and phosphorylates a threonine 573 residue on radixin. Akt-mediated phosphorylation protects radixin from ubiquitin-dependent proteasomal degradation, thereby enhancing radixin protein stability, which permits proper neurite outgrowth and growth cone formation. Conversely, the inhibition of Akt kinase or disruption of Akt-dependent phosphorylation reduces the binding affinity of radixin to F-actin as well as lowers radixin protein levels, resulting in decreased neurite outgrowth and growth cone formation. Our findings suggest that Akt signaling regulates neurite outgrowth by stabilizing radixin interactions with F-actin, thus facilitating local F-actin dynamics.
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Affiliation(s)
- Eun-Ju Jin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Hyo Rim Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Inwoo Hwang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Byeong-Seong Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Jeong-Yun Choi
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Kye Won Park
- Department of Food Science and Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, 05505, Korea
| | - Jee-Yin Ahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea. .,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea. .,Samsung Medical Center, Seoul, 06351, Korea.
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16
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Regulation of ErbB2 localization and function in breast cancer cells by ERM proteins. Oncotarget 2018; 7:25443-60. [PMID: 27029001 PMCID: PMC5041916 DOI: 10.18632/oncotarget.8327] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 03/10/2016] [Indexed: 12/20/2022] Open
Abstract
The ERM protein family is implicated in processes such as signal transduction, protein trafficking, cell proliferation and migration. Consequently, dysregulation of ERM proteins has been described to correlate with carcinogenesis of different cancer types. However, the underlying mechanisms are poorly understood. Here, we demonstrate a novel functional interaction between ERM proteins and the ErbB2 receptor tyrosine kinase in breast cancer cells. We show that the ERM proteins ezrin and radixin are associated with ErbB2 receptors at the plasma membrane, and depletion or functional inhibition of ERM proteins destabilizes the interaction of ErbB2 with ErbB3, Hsp90 and Ebp50. Accompanied by the dissociation of this protein complex, binding of ErbB2 to the ubiquitin-ligase c-Cbl is increased, and ErbB2 becomes dephosphorylated, ubiquitinated and internalized. Furthermore, signaling via Akt- and Erk-mediated pathways is impaired upon ERM inhibition. Finally, interference with ERM functionality leads to receptor degradation and reduced cellular levels of ErbB2 and ErbB3 receptors in breast cancer cells.
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17
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Vega IE, Umstead A, Wygant CM, Beck JS, Counts SE. Ezrin Expression is Increased During Disease Progression in a Tauopathy Mouse Model and Alzheimer's Disease. Curr Alzheimer Res 2018; 15:1086-1095. [PMID: 30101710 PMCID: PMC6522142 DOI: 10.2174/1567205015666180813152043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/20/2018] [Accepted: 08/07/2018] [Indexed: 01/10/2023]
Abstract
BACKGROUND The lack of diagnostic tools and disease-modifying treatments against Alzheimer's disease (AD) and related disorders, collectively known as tauopathies, has led to a socioeconomic burden of epidemic proportion. Proteomics approaches can be used to identify novel proteome changes that could help us understand the pathogenesis of tau-related pathological hallmarks and/or cellular stress responses associated with tauopathy. These studies, however, need to be conducted taking into consideration brain region specificity and stage of neurodegeneration in order to provide insights about the pathological role of the identified proteins. METHODS We used a tauopathy mouse model (JNPL3) that expresses human tau bearing a P301L mutation and develops motor impairment, the severity of which correlates with the increased accumulation of pathological tau. Tissue was dissected from asymptomatic and severely motor impaired JNPL3 mice as well as non-transgenic littermate controls and subjected to two-dimensional gel electrophoresis. Differentially abundant protein spots were identified by tandem mass spectrometry. Postmortem mild cognitive impairment (MCI), AD and normal aging controls were used to validate the pathological significance of the identified protein. RESULTS Ezrin was identified as a protein that is upregulated in tau-mediated neurodegeneration. We demonstrate that Ezrin protein abundance increased in JNPL3 mice preceded motor impairment and was sustained in severely motor impaired mice. Ezrin expression was also increased in the temporal cortex of MCI and AD patients. CONCLUSION The results demonstrate that increased Ezrin protein abundance changes are associated with the early stages of neurodegeneration in tauopathy models and human disease. Understanding the role of Ezrin in tauopathies such as AD may provide new insights for targeting tau-mediated neurodegeneration.
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Affiliation(s)
- Irving E. Vega
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
- Michigan Alzheimer’s Disease Core Center, University of Michigan, Michigan State University and Wayne State University, Michigan, USA
| | - Andrew Umstead
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Cassandra M. Wygant
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - John S. Beck
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Scott E. Counts
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
- Michigan Alzheimer’s Disease Core Center, University of Michigan, Michigan State University and Wayne State University, Michigan, USA
- Department of Family Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
- Hauenstein Neurosciences Center, Mercy Health Saint Mary’s Hospital, Grand Rapids, Michigan, USA
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18
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Estabridis HM, Jana A, Nain A, Odde DJ. Cell Migration in 1D and 2D Nanofiber Microenvironments. Ann Biomed Eng 2017; 46:392-403. [PMID: 29150767 PMCID: PMC5809563 DOI: 10.1007/s10439-017-1958-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/10/2017] [Indexed: 12/31/2022]
Abstract
Understanding how cells migrate in fibrous environments is important in wound healing, immune function, and cancer progression. A key question is how fiber orientation and network geometry influence cell movement. Here we describe a quantitative, modeling-based approach toward identifying the mechanisms by which cells migrate in fibrous geometries having well controlled orientation. Specifically, U251 glioblastoma cells were seeded onto non-electrospinning Spinneret based tunable engineering parameters fiber substrates that consist of networks of suspended 400 nm diameter nanofibers. Cells were classified based on the local fiber geometry and cell migration dynamics observed by light microscopy. Cells were found in three distinct geometries: adhering two a single fiber, adhering to two parallel fibers, and adhering to a network of orthogonal fibers. Cells adhering to a single fiber or two parallel fibers can only move in one dimension along the fiber axis, whereas cells on a network of orthogonal fibers can move in two dimensions. We found that cells move faster and more persistently in 1D geometries than in 2D, with cell migration being faster on parallel fibers than on single fibers. To explain these behaviors mechanistically, we simulated cell migration in the three different geometries using a motor-clutch based model for cell traction forces. Using nearly identical parameter sets for each of the three cases, we found that the simulated cells naturally replicated the reduced migration in 2D relative to 1D geometries. In addition, the modestly faster 1D migration on parallel fibers relative to single fibers was captured using a correspondingly modest increase in the number of clutches to reflect increased surface area of adhesion on parallel fibers. Overall, the integrated modeling and experimental analysis shows that cell migration in response to varying fibrous geometries can be explained by a simple mechanical readout of geometry via a motor-clutch mechanism.
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Affiliation(s)
- Horacio M Estabridis
- Department of Biomedical Engineering, University of Minnesota, 312 Church St. SE, 7-132 Nils-Hasselmo Hall, Minneapolis, MN, 55455, USA
| | - Aniket Jana
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Amrinder Nain
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - David J Odde
- Department of Biomedical Engineering, University of Minnesota, 312 Church St. SE, 7-132 Nils-Hasselmo Hall, Minneapolis, MN, 55455, USA.
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19
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Ko HR, Kwon IS, Hwang I, Jin EJ, Shin JH, Brennan-Minnella AM, Swanson R, Cho SW, Lee KH, Ahn JY. Akt1-Inhibitor of DNA binding2 is essential for growth cone formation and axon growth and promotes central nervous system axon regeneration. eLife 2016; 5. [PMID: 27938661 PMCID: PMC5153247 DOI: 10.7554/elife.20799] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 11/28/2016] [Indexed: 02/02/2023] Open
Abstract
Mechanistic studies of axon growth during development are beneficial to the search for neuron-intrinsic regulators of axon regeneration. Here, we discovered that, in the developing neuron from rat, Akt signaling regulates axon growth and growth cone formation through phosphorylation of serine 14 (S14) on Inhibitor of DNA binding 2 (Id2). This enhances Id2 protein stability by means of escape from proteasomal degradation, and steers its localization to the growth cone, where Id2 interacts with radixin that is critical for growth cone formation. Knockdown of Id2, or abrogation of Id2 phosphorylation at S14, greatly impairs axon growth and the architecture of growth cone. Intriguingly, reinstatement of Akt/Id2 signaling after injury in mouse hippocampal slices redeemed growth promoting ability, leading to obvious axon regeneration. Our results suggest that Akt/Id2 signaling is a key module for growth cone formation and axon growth, and its augmentation plays a potential role in CNS axonal regeneration. DOI:http://dx.doi.org/10.7554/eLife.20799.001
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Affiliation(s)
- Hyo Rim Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Il-Sun Kwon
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Inwoo Hwang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Eun-Ju Jin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Joo-Ho Shin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Angela M Brennan-Minnella
- The Department of Neurology, University of California, San Francisco Medical Center, San Francisco, United States
| | - Raymond Swanson
- The Department of Neurology, University of California, San Francisco Medical Center, San Francisco, United States
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan, College of Medicine, Seoul, Republic of Korea
| | - Kyung-Hoon Lee
- Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Department of Anatomy, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Jee-Yin Ahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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20
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Cicvaric A, Yang J, Krieger S, Khan D, Kim EJ, Dominguez-Rodriguez M, Cabatic M, Molz B, Acevedo Aguilar JP, Milicevic R, Smani T, Breuss JM, Kerjaschki D, Pollak DD, Uhrin P, Monje FJ. The brain-tumor related protein podoplanin regulates synaptic plasticity and hippocampus-dependent learning and memory. Ann Med 2016; 48:652-668. [PMID: 27558977 PMCID: PMC5125287 DOI: 10.1080/07853890.2016.1219455] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/14/2016] [Accepted: 07/25/2016] [Indexed: 01/15/2023] Open
Abstract
INTRODUCTION Podoplanin is a cell-surface glycoprotein constitutively expressed in the brain and implicated in human brain tumorigenesis. The intrinsic function of podoplanin in brain neurons remains however uncharacterized. MATERIALS AND METHODS Using an established podoplanin-knockout mouse model and electrophysiological, biochemical, and behavioral approaches, we investigated the brain neuronal role of podoplanin. RESULTS Ex-vivo electrophysiology showed that podoplanin deletion impairs dentate gyrus synaptic strengthening. In vivo, podoplanin deletion selectively impaired hippocampus-dependent spatial learning and memory without affecting amygdala-dependent cued fear conditioning. In vitro, neuronal overexpression of podoplanin promoted synaptic activity and neuritic outgrowth whereas podoplanin-deficient neurons exhibited stunted outgrowth and lower levels of p-Ezrin, TrkA, and CREB in response to nerve growth factor (NGF). Surface Plasmon Resonance data further indicated a physical interaction between podoplanin and NGF. DISCUSSION This work proposes podoplanin as a novel component of the neuronal machinery underlying neuritogenesis, synaptic plasticity, and hippocampus-dependent memory functions. The existence of a relevant cross-talk between podoplanin and the NGF/TrkA signaling pathway is also for the first time proposed here, thus providing a novel molecular complex as a target for future multidisciplinary studies of the brain function in the physiology and the pathology. Key messages Podoplanin, a protein linked to the promotion of human brain tumors, is required in vivo for proper hippocampus-dependent learning and memory functions. Deletion of podoplanin selectively impairs activity-dependent synaptic strengthening at the neurogenic dentate-gyrus and hampers neuritogenesis and phospho Ezrin, TrkA and CREB protein levels upon NGF stimulation. Surface plasmon resonance data indicates a physical interaction between podoplanin and NGF. On these grounds, a relevant cross-talk between podoplanin and NGF as well as a role for podoplanin in plasticity-related brain neuronal functions is here proposed.
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Affiliation(s)
- Ana Cicvaric
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Jiaye Yang
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Sigurd Krieger
- Clinical Institute of Pathology, Medical University of Vienna,
Vienna,
Austria
| | - Deeba Khan
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Eun-Jung Kim
- Paik Institute for Clinical Research, Inje University College of Medicine,
Busan,
Republic of Korea
| | - Manuel Dominguez-Rodriguez
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Maureen Cabatic
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Barbara Molz
- Psychology University of York,
Heslington York,
UK
| | - Juan Pablo Acevedo Aguilar
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Radoslav Milicevic
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Tarik Smani
- Grupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla,
Seville,
Spain
| | - Johannes M. Breuss
- Department of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Dontscho Kerjaschki
- Clinical Institute of Pathology, Medical University of Vienna,
Vienna,
Austria
| | - Daniela D. Pollak
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Pavel Uhrin
- Department of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
| | - Francisco J. Monje
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna,
Vienna,
Austria
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21
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DeWitt JJ, Grepo N, Wilkinson B, Evgrafov OV, Knowles JA, Campbell DB. Impact of the Autism-Associated Long Noncoding RNA MSNP1AS on Neuronal Architecture and Gene Expression in Human Neural Progenitor Cells. Genes (Basel) 2016; 7:genes7100076. [PMID: 27690106 PMCID: PMC5083915 DOI: 10.3390/genes7100076] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/08/2016] [Accepted: 09/23/2016] [Indexed: 01/26/2023] Open
Abstract
We previously identified the long noncoding RNA (lncRNA) MSNP1AS (moesin pseudogene 1, antisense) as a functional element revealed by genome wide significant association with autism spectrum disorder (ASD). MSNP1AS expression was increased in the postmortem cerebral cortex of individuals with ASD and particularly in individuals with the ASD-associated genetic markers on chromosome 5p14.1. Here, we mimicked the overexpression of MSNP1AS observed in postmortem ASD cerebral cortex in human neural progenitor cell lines to determine the impact on neurite complexity and gene expression. ReNcell CX and SK-N-SH were transfected with an overexpression vector containing full-length MSNP1AS. Neuronal complexity was determined by the number and length of neuronal processes. Gene expression was determined by strand-specific RNA sequencing. MSNP1AS overexpression decreased neurite number and neurite length in both human neural progenitor cell lines. RNA sequencing revealed changes in gene expression in proteins involved in two biological processes: protein synthesis and chromatin remodeling. These data indicate that overexpression of the ASD-associated lncRNA MSNP1AS alters the number and length of neuronal processes. The mechanisms by which MSNP1AS overexpression impacts neuronal differentiation may involve protein synthesis and chromatin structure. These same biological processes are also implicated by rare mutations associated with ASD, suggesting convergent mechanisms.
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Affiliation(s)
- Jessica J DeWitt
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
| | - Nicole Grepo
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
| | - Brent Wilkinson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
| | - Oleg V Evgrafov
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
- Department of Psychiatry and the Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
| | - James A Knowles
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
- Department of Psychiatry and the Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
| | - Daniel B Campbell
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
- Department of Psychiatry and the Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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Antoine-Bertrand J, Fu M, Lamarche-Vane N. Direct measurement of oscillatory RhoA activity in embryonic cortical neurons stimulated with the axon guidance cue netrin-1 using fluorescence resonance energy transfer. Biol Cell 2016; 108:115-26. [PMID: 26787017 DOI: 10.1111/boc.201500077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/15/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND INFORMATION Rho GTPases play an essential role during the development of the nervous system. They induce cytoskeletal rearrangements that are critical for the regulation of axon outgrowth and guidance. It is generally accepted that Rac1 and Cdc42 are positive regulators of axon outgrowth and guidance, whereas RhoA is a negative regulator. However, spatiotemporal control of their activity can modify the function of Rho GTPases during axonal morphogenesis. Signalling downstream of the axon guidance cue netrin-1 and its receptor deleted in colorectal cancer (DCC) triggers the activation of Rac1 and the inhibition of RhoA to promote axon outgrowth. However, our previous work also suggests that netrin-1/DCC signalling can activate RhoA in a time- and region-specific manner. RESULTS Here, we visualised RhoA activation in response to netrin-1 in live embryonic cortical neurons using fluorescence resonance energy transfer. RhoA activity oscillated in unstimulated neurons and netrin-1 increased the amplitude of the oscillations in growth cones after 5 min of stimulation. Within this period of time, netrin-1 transiently increased RhoA activity and modulated the pattern of RhoA oscillations. We found that the timing of netrin-1-induced RhoA activation was different in whole neurons, cell bodies and growth cones. CONCLUSIONS We conclude that netrin-1 modulates the spatiotemporal activation of RhoA in embryonic cortical neurons. SIGNIFICANCE This study demonstrates for the first time the short-term localised activation of RhoA in neuronal growth cones by the axon guidance cue netrin-1.
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Affiliation(s)
- Judith Antoine-Bertrand
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.,Cancer Research Program, Research Institute of the McGill University Health Centre (RI-MUHC), Montreal, Quebec, Canada
| | - Min Fu
- Cancer Research Program, Research Institute of the McGill University Health Centre (RI-MUHC), Montreal, Quebec, Canada
| | - Nathalie Lamarche-Vane
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.,Cancer Research Program, Research Institute of the McGill University Health Centre (RI-MUHC), Montreal, Quebec, Canada
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Substrate Availability of Mutant SPT Alters Neuronal Branching and Growth Cone Dynamics in Dorsal Root Ganglia. J Neurosci 2016; 35:13713-9. [PMID: 26446223 DOI: 10.1523/jneurosci.1403-15.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
UNLABELLED Serine palmitoyltransferase (SPT) is a key enzyme in the first step of sphingolipid biosynthesis. Mutations in the SPTLC1 gene that encodes for SPT subunits cause hereditary sensory neuropathy type 1. However, little is understood about how mutant SPT regulates mechanisms of sensory neuron and axonal growth. Using transgenic mice overexpressing the C133W SPT mutant, we found that mutant dorsal root ganglia (DRG) during growth in vitro exhibit increased neurite length and branching, coinciding with elevated expression of actin-cross-linking proteins at the neuronal growth cone, namely phosphorylated Ezrin/Radixin/Moesin. In addition, inhibition of SPT was able to reverse the mutant phenotype. Because mutant SPT preferentially uses l-alanine over its canonical substrate l-serine, we also investigated the effects of substrate availability on DRG neurons. Supplementation with l-serine or removal of l-alanine independently restored normal growth patterns in mutant SPTLC1(C133W) DRG. Therefore, we report that substrate availability and selectivity of SPT influence the regulation of neurite growth in DRG neurons. SIGNIFICANCE STATEMENT Hereditary sensory neuropathy type 1 is an autosomal-dominant disorder that leads to a sensory neuropathy due to mutations in the serine palmitoyltransferase (SPT) enzyme. We investigated how mutant SPT and substrate levels regulate neurite growth. Because SPT is an important enzyme in the synthesis of sphingolipids, our data are of broader significance to other peripheral and metabolic disorders.
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Menon S, Gupton SL. Building Blocks of Functioning Brain: Cytoskeletal Dynamics in Neuronal Development. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 322:183-245. [PMID: 26940519 PMCID: PMC4809367 DOI: 10.1016/bs.ircmb.2015.10.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neural connectivity requires proper polarization of neurons, guidance to appropriate target locations, and establishment of synaptic connections. From when neurons are born to when they finally reach their synaptic partners, neurons undergo constant rearrangment of the cytoskeleton to achieve appropriate shape and polarity. Of particular importance to neuronal guidance to target locations is the growth cone at the tip of the axon. Growth-cone steering is also dictated by the underlying cytoskeleton. All these changes require spatiotemporal control of the cytoskeletal machinery. This review summarizes the proteins that are involved in modulating the actin and microtubule cytoskeleton during the various stages of neuronal development.
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Affiliation(s)
- Shalini Menon
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, United States of America
| | - Stephanie L Gupton
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, United States of America; Neuroscience Center and Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC, United States of America; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, United States of America.
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25
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Colombo F, Meldolesi J. L1-CAM and N-CAM: From Adhesion Proteins to Pharmacological Targets. Trends Pharmacol Sci 2015; 36:769-781. [PMID: 26478212 DOI: 10.1016/j.tips.2015.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 07/31/2015] [Accepted: 08/04/2015] [Indexed: 12/14/2022]
Abstract
L1 cell adhesion molecule (L1-CAM) and neural cell adhesion molecule (N-CAM), key members of the immunoglobulin-like CAM (Ig-CAM) family, were first recognized to play critical roles in surface interactions of neurons, by binding with each other and with extracellular matrix (ECM) proteins. Subsequently, adhesion was recognized to include signaling due to both activation of β-integrin, with the generation of intracellular cascades, and integration with the surface cytoskeleton. The importance of the two Ig-CAMs was revealed by their activation of the tyrosine kinase receptors of fibroblast growth factor (FGF), epidermal growth factor (EGF), and nerve growth factor (NGF). Based on these complex signaling properties, L1-CAM and N-CAM have become of great potential pharmacological interest in neurons and cancers. Treatment of neurodegenerative disorders and cognitive deficits of neurons is aimed to increase the cell Ig-CAM tone, possibly provided by synthetic/mimetic peptides. In cancer cells, where Ig-CAMs are often overexpressed, the proteins are employed for prognosis. The approaches to therapy are based on protein downregulation, antibodies, and adoptive immunotherapy.
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Affiliation(s)
- Federico Colombo
- Vita-Salute San Raffaele University and S. Raffaele Scientific Institute, Via Olgettina 58, 20132 Milan, Italy
| | - Jacopo Meldolesi
- Vita-Salute San Raffaele University and S. Raffaele Scientific Institute, Via Olgettina 58, 20132 Milan, Italy.
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26
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Weitsman G, Lawler K, Kelleher MT, Barrett JE, Barber PR, Shamil E, Festy F, Patel G, Fruhwirth GO, Huang L, Tullis ID, Woodman N, Ofo E, Ameer-Beg SM, Irshad S, Condeelis J, Gillett CE, Ellis PA, Vojnovic B, Coolen AC, Ng T. Imaging tumour heterogeneity of the consequences of a PKCα-substrate interaction in breast cancer patients. Biochem Soc Trans 2014; 42:1498-505. [PMID: 25399560 PMCID: PMC4259014 DOI: 10.1042/bst20140165] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Breast cancer heterogeneity demands that prognostic models must be biologically driven and recent clinical evidence indicates that future prognostic signatures need evaluation in the context of early compared with late metastatic risk prediction. In pre-clinical studies, we and others have shown that various protein-protein interactions, pertaining to the actin microfilament-associated proteins, ezrin and cofilin, mediate breast cancer cell migration, a prerequisite for cancer metastasis. Moreover, as a direct substrate for protein kinase Cα, ezrin has been shown to be a determinant of cancer metastasis for a variety of tumour types, besides breast cancer; and has been described as a pivotal regulator of metastasis by linking the plasma membrane to the actin cytoskeleton. In the present article, we demonstrate that our tissue imaging-derived parameters that pertain to or are a consequence of the PKC-ezrin interaction can be used for breast cancer prognostication, with inter-cohort reproducibility. The application of fluorescence lifetime imaging microscopy (FLIM) in formalin-fixed paraffin-embedded patient samples to probe protein proximity within the typically <10 nm range to address the oncological challenge of tumour heterogeneity, is discussed.
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Affiliation(s)
- Gregory Weitsman
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
| | - Katherine Lawler
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
- Department of Mathematics, King’s College London, Strand Campus, London WC2R 2LS, U.K
| | - Muireann T. Kelleher
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
- Department of Medical Oncology, St George’s NHS Trust, London SW17 0QT, U.K
| | - James E. Barrett
- Department of Mathematics, King’s College London, Strand Campus, London WC2R 2LS, U.K
| | - Paul R. Barber
- Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, U.K
| | - Eamon Shamil
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
| | - Frederic Festy
- Biomaterials, Biomimetics and Biophotonics Division, King’s College London Dental Institute, London SE1 9RT, U.K
| | - Gargi Patel
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
- Department of Medical Oncology, Guy’s and St. Thomas Foundation Trust, London SE1 9RT, U.K
| | - Gilbert O. Fruhwirth
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
- Division of Imaging Science and Biomedical Engineering, King’s College London, London SE1 7EH, U.K
| | - Lufei Huang
- Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, U.K
| | - Iain D.C. Tullis
- Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, U.K
| | - Natalie Woodman
- Guy’s & St. Thomas’ Breast Tissue & Data Bank, King’s College London, Guy’s Hospital, London SE1 9RT, U.K
| | - Enyinnaya Ofo
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
| | - Simon M. Ameer-Beg
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
| | - Sheeba Irshad
- Breakthrough Breast Cancer Research Unit, Department of Research Oncology, Guy’s Hospital King’s College London School of Medicine, London, SE1 9RT, U.K
| | - John Condeelis
- Tumor Microenvironment and Metastasis Program, Albert Einstein Cancer Center, New York, NY 10461, U.S.A
| | - Cheryl E. Gillett
- Guy’s & St. Thomas’ Breast Tissue & Data Bank, King’s College London, Guy’s Hospital, London SE1 9RT, U.K
| | - Paul A. Ellis
- Department of Medical Oncology, Guy’s and St. Thomas Foundation Trust, London SE1 9RT, U.K
| | - Borivoj Vojnovic
- Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, U.K
- Randall Division of Cell & Molecular Biophysics, King’s College London, London, U.K
| | - Anthony C.C. Coolen
- Department of Mathematics, King’s College London, Strand Campus, London WC2R 2LS, U.K
| | - Tony Ng
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, Guy’s Medical School Campus, London SE1 1UL, U.K
- Breakthrough Breast Cancer Research Unit, Department of Research Oncology, Guy’s Hospital King’s College London School of Medicine, London, SE1 9RT, U.K
- UCL Cancer Institute, Paul O’Gorman Building, University College London, London WC1E 6DD, U.K
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Matsumoto Y, Inden M, Tamura A, Hatano R, Tsukita S, Asano S. Ezrin mediates neuritogenesis via down-regulation of RhoA activity in cultured cortical neurons. PLoS One 2014; 9:e105435. [PMID: 25144196 PMCID: PMC4140760 DOI: 10.1371/journal.pone.0105435] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/18/2014] [Indexed: 01/06/2023] Open
Abstract
Neuronal morphogenesis is implicated in neuronal function and development with rearrangement of cytoskeletal organization. Ezrin, a member of Ezrin/Radixin/Moesin (ERM) proteins links between membrane proteins and actin cytoskeleton, and contributes to maintenance of cellular function and morphology. In cultured hippocampal neurons, suppression of both radixin and moesin showed deficits in growth cone morphology and neurite extensions. Down-regulation of ezrin using siRNA caused impairment of netrin-1-induced axon outgrowth in cultured cortical neurons. However, roles of ezrin in the neuronal morphogenesis of the cultured neurons have been poorly understood. In this report, we performed detailed studies on the roles of ezrin in the cultured cortical neurons prepared from the ezrin knockdown (Vil2kd/kd) mice embryo that showed a very small amount of ezrin expression compared with the wild-type (Vil2+/+) neurons. Ezrin was mainly expressed in cell body in the cultured cortical neurons. We demonstrated that the cultured cortical neurons prepared from the Vil2kd/kd mice embryo exhibited impairment of neuritogenesis. Moreover, we observed increased RhoA activity and phosphorylation of myosin light chain 2 (MLC2), as a downstream effector of RhoA in the Vil2kd/kd neurons. In addition, inhibition of Rho kinase and myosin II rescued the impairment of neuritogenesis in the Vil2kd/kd neurons. These data altogether suggest a novel role of ezrin in the neuritogenesis of the cultured cortical neurons through down-regulation of RhoA activity.
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Affiliation(s)
- Yosuke Matsumoto
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Masatoshi Inden
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Gifu Pharmaceutical University, Gifu, Japan
| | - Atsushi Tamura
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Ryo Hatano
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Sachiko Tsukita
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Shinji Asano
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
- * E-mail:
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28
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Santos G, Valenzuela-Fernández A, Torres NV. Quantitative analysis of the processes and signaling events involved in early HIV-1 infection of T cells. PLoS One 2014; 9:e103845. [PMID: 25105875 PMCID: PMC4126662 DOI: 10.1371/journal.pone.0103845] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 07/02/2014] [Indexed: 11/24/2022] Open
Abstract
Lymphocyte invasion by HIV-1 is a complex, highly regulated process involving many different types of molecules that is prompted by the virus's association with viral receptors located at the cell-surface membrane that culminates in the formation of a fusion pore through which the virus enters the cell. A great deal of work has been done to identify the key actors in the process and determine the regulatory interactions; however, there have been no reports to date of attempts being made to fully understand the system dynamics through a systemic, quantitative modeling approach. In this paper, we introduce a dynamic mathematical model that integrates the available information on the molecular events involved in lymphocyte invasion. Our model shows that moesin activation is induced by virus signaling, while filamin-A is mobilized by the receptor capping. Actin disaggregation from the cap is facilitated by cofilin. Cofilin is inactivated by HIV-1 signaling in activated lymphocytes, while in resting lymphocytes another signal is required to activate cofilin in the later stages in order to accelerate the decay of the aggregated actin as a restriction factor for the viral entry. Furthermore, stopping the activation signaling of moesin is sufficient to liberate the actin filaments from the cap. The model also shows the positive effect of gelsolin on actin capping by means of the nucleation effect. These findings allow us to propose novel approaches in the search for new therapeutic strategies. In particular, gelsolin inhibition is seen as a promising target for preventing HIV-1 entry into lymphocytes, due to its role in facilitating the capping needed for the invasion. Also it is shown that HIV-1 should overcome the cortical actin barrier during early infection and predicts the different susceptibility of CD4+ T cells to be infected in terms of actin cytoskeleton dynamics driven by associated cellular factors.
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Affiliation(s)
- Guido Santos
- Grupo de Biología de Sistemas y Modelización Matemática, Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Facultad de Biología, Universidad de La Laguna, San Cristóbal de La Laguna, Tenerife, España
- Instituto de Tecnología Biomédica, Universidad de La Laguna, San Cristóbal de La Laguna, Tenerife, Spain
| | - Agustín Valenzuela-Fernández
- Laboratorio de Inmunología Celular y Viral, Departamento de Medicina Física y Farmacología, Facultad de Medicina, Universidad de La Laguna, San Cristóbal de La Laguna, Tenerife, España
- * E-mail: (AV-F); (NVT)
| | - Néstor V. Torres
- Grupo de Biología de Sistemas y Modelización Matemática, Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Facultad de Biología, Universidad de La Laguna, San Cristóbal de La Laguna, Tenerife, España
- Instituto de Tecnología Biomédica, Universidad de La Laguna, San Cristóbal de La Laguna, Tenerife, Spain
- * E-mail: (AV-F); (NVT)
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29
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Ueda Y. The Role of Phosphoinositides in Synapse Function. Mol Neurobiol 2014; 50:821-38. [DOI: 10.1007/s12035-014-8768-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 06/01/2014] [Indexed: 11/30/2022]
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Abstract
During development extrinsic guidance cues modulate the peripheral actin network in growth cones to direct axons to their targets. We wanted to understand the role of the actin nucleator Arp2/3 in growth cone actin dynamics and guidance. Since growth cones migrate in association with diverse adhesive substrates during development, we probed the hypothesis that the functional significance of Arp2/3 is substrate dependent. We report that Arp2/3 inhibition led to a reduction in the number of filopodia and growth cone F-actin content on laminin and L1. However, we found substrate-dependent differences in growth cone motility, actin retrograde flow, and guidance after Arp2/3 inhibition, suggesting that its role, and perhaps that of other actin binding proteins, in growth cone motility is substrate dependent.
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31
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Laßek M, Weingarten J, Volknandt W. The Proteome of the Murine Presynaptic Active Zone. Proteomes 2014; 2:243-257. [PMID: 28250380 PMCID: PMC5302740 DOI: 10.3390/proteomes2020243] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/09/2014] [Accepted: 04/21/2014] [Indexed: 01/09/2023] Open
Abstract
The proteome of the presynaptic active zone controls neurotransmitter release and the short- and long-term structural and functional dynamics of the nerve terminal. The proteinaceous inventory of the presynaptic active zone has recently been reported. This review will evaluate the subcellular fractionation protocols and the proteomic approaches employed. A breakthrough for the identification of the proteome of the presynaptic active zone was the successful employment of antibodies directed against a cytosolic epitope of membrane integral synaptic vesicle proteins for the immunopurification of synaptic vesicles docked to the presynaptic plasma membrane. Combining immunopurification and subsequent analytical mass spectrometry, hundreds of proteins, including synaptic vesicle proteins, components of the presynaptic fusion and retrieval machinery, proteins involved in intracellular and extracellular signaling and a large variety of adhesion molecules, were identified. Numerous proteins regulating the rearrangement of the cytoskeleton are indicative of the functional and structural dynamics of the presynapse. This review will critically discuss both the experimental approaches and prominent protein candidates identified. Many proteins have not previously been assigned to the presynaptic release sites and may be directly involved in the short- and long-term structural modulation of the presynaptic compartment. The identification of proteinaceous constituents of the presynaptic active zone provides the basis for further analyzing the interaction of presynaptic proteins with their targets and opens novel insights into the functional role of these proteins in neuronal communication.
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Affiliation(s)
- Melanie Laßek
- Institute for Cell Biology and Neuroscience, Department Molecular and Cellular Neurobiology, Max von Laue Str. 13, 60438 Frankfurt am Main, Germany.
| | - Jens Weingarten
- Institute for Cell Biology and Neuroscience, Department Molecular and Cellular Neurobiology, Max von Laue Str. 13, 60438 Frankfurt am Main, Germany.
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Department Molecular and Cellular Neurobiology, Max von Laue Str. 13, 60438 Frankfurt am Main, Germany.
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32
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Weingarten J, Lassek M, Mueller BF, Rohmer M, Lunger I, Baeumlisberger D, Dudek S, Gogesch P, Karas M, Volknandt W. The proteome of the presynaptic active zone from mouse brain. Mol Cell Neurosci 2014; 59:106-18. [PMID: 24534009 DOI: 10.1016/j.mcn.2014.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 01/07/2023] Open
Abstract
Neurotransmitter release as well as the structural and functional dynamics of the presynaptic active zone is controlled by proteinaceous components. Here we describe for the first time an experimental approach for the isolation of the presynaptic active zone from individual mouse brains, a prerequisite for understanding the functional inventory of the presynaptic protein network and for the later analysis of changes occurring in mutant mice. Using a monoclonal antibody against the ubiquitous synaptic vesicle protein SV2 we immunopurified synaptic vesicles docked to the presynaptic plasma membrane. Enrichment studies by means of Western blot analysis and mass spectrometry identified 485 proteins belonging to an impressive variety of functional categories. Our data suggest that presynaptic active zones represent focal hot spots that are not only involved in the regulation of neurotransmitter release but also in multiple structural and functional alterations the adult nerve terminal undergoes during neural activity in adult CNS. They furthermore open new avenues for characterizing alterations in the active zone proteome of mutant mice and their corresponding controls, including the various mouse models of neurological diseases.
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Affiliation(s)
- Jens Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Melanie Lassek
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Benjamin F Mueller
- Institute of Pharmaceutical Chemistry, Cluster of Excellence "Macromolecular Complexes", Goethe-University, Frankfurt am Main, Germany
| | - Marion Rohmer
- Institute of Pharmaceutical Chemistry, Cluster of Excellence "Macromolecular Complexes", Goethe-University, Frankfurt am Main, Germany
| | - Ilaria Lunger
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | | | - Simone Dudek
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Patricia Gogesch
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Michael Karas
- Institute of Pharmaceutical Chemistry, Cluster of Excellence "Macromolecular Complexes", Goethe-University, Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany.
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Qiu T, Yin Y, Li B, Xie L, Yan Q, Dai H, Wang X, Li S. PDLLA/PRGD/β-TCP conduits build the neurotrophin-rich microenvironment suppressing the oxidative stress and promoting the sciatic nerve regeneration. J Biomed Mater Res A 2014; 102:3734-43. [PMID: 24408878 DOI: 10.1002/jbm.a.35078] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 11/23/2013] [Accepted: 12/31/2013] [Indexed: 12/16/2022]
Abstract
A novel nerve guidance conduit comprising poly{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]} (PRGD), poly (d,l-lactic acid) (PDLLA) and β-tricalcium phosphate (β-TCP) was constructed to facilitate the peripheral nerve regeneration. From the comparative study, PDLLA/PRGD/β-TCP conduit achieved the best recovery in regard of the ultrastructure observation and the SFI evaluation. At the first stage of the injury (7 days), the maximum expression augments in ZnSOD (6.4 folds) and GPX4 (6.8 folds) were observed in PDLLA/PRGD/β-TCP group; while striking rise in actin (6.8 folds), tubulin (5.6 folds), and ERM components expressions were observed later (35 days). Meanwhile, compared with PDLLA and PDLLA/PRGD conduits, PDLLA/PRGD/β-TCP conduits achieved the highest local nerve growth factor (NGF) content and an accumulating BDNF content. We speculated that addition of RGD and β-TCP in the composites were the main positive factors to build the microenvironment rich in NGF and BDNF, which help to counteract with the oxidative stress and to boost the cytoskeletal protein expressions. Therefore, PDLLA/PRGD/β-TCP could be promising composites used in peripheral nerve regeneration.
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Affiliation(s)
- Tong Qiu
- Biomedical Materials and Engineering Center, Wuhan University of Technology, Wuhan, 430070, People's Republic of China
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Akiyama H, Kamiguchi H. Second messenger networks for accurate growth cone guidance. Dev Neurobiol 2013; 75:411-22. [PMID: 24285606 DOI: 10.1002/dneu.22157] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/21/2013] [Accepted: 11/25/2013] [Indexed: 02/02/2023]
Abstract
Growth cones are able to navigate over long distances to find their appropriate target by following guidance cues that are often presented to them in the form of an extracellular gradient. These external cues are converted into gradients of specific signaling molecules inside growth cones, while at the same time these internal signals are amplified. The amplified instruction is then used to generate asymmetric changes in the growth cone turning machinery so that one side of the growth cone migrates at a rate faster than the other side, and thus the growth cone turns toward or away from the external cue. This review examines how signal specification and amplification can be achieved inside the growth cone by multiple second messenger signaling pathways activated downstream of guidance cues. These include the calcium ion, cyclic nucleotide, and phosphatidylinositol signaling pathways.
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Affiliation(s)
- Hiroki Akiyama
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
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Gomez TM, Letourneau PC. Actin dynamics in growth cone motility and navigation. J Neurochem 2013; 129:221-34. [PMID: 24164353 DOI: 10.1111/jnc.12506] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/07/2013] [Accepted: 10/16/2013] [Indexed: 12/17/2022]
Abstract
Motile growth cones lead growing axons through developing tissues to synaptic targets. These behaviors depend on the organization and dynamics of actin filaments that fill the growth cone leading margin [peripheral (P-) domain]. Actin filament organization in growth cones is regulated by actin-binding proteins that control all aspects of filament assembly, turnover, interactions with other filaments and cytoplasmic components, and participation in producing mechanical forces. Actin filament polymerization drives protrusion of sensory filopodia and lamellipodia, and actin filament connections to the plasma membrane link the filament network to adhesive contacts of filopodia and lamellipodia with other surfaces. These contacts stabilize protrusions and transduce mechanical forces generated by actomyosin activity into traction that pulls an elongating axon along the path toward its target. Adhesive ligands and extrinsic guidance cues bind growth cone receptors and trigger signaling activities involving Rho GTPases, kinases, phosphatases, cyclic nucleotides, and [Ca++] fluxes. These signals regulate actin-binding proteins to locally modulate actin polymerization, interactions, and force transduction to steer the growth cone leading margin toward the sources of attractive cues and away from repellent guidance cues.
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Affiliation(s)
- Timothy M Gomez
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
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Olbrich L, Wessel L, Balakrishnan-Renuka A, Böing M, Brand-Saberi B, Theiss C. Rapid impact of progesterone on the neuronal growth cone. Endocrinology 2013; 154:3784-95. [PMID: 23913445 DOI: 10.1210/en.2013-1175] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the last two decades, sensory neurons and Schwann cells in the dorsal root ganglia (DRG) were shown to express the rate-limiting enzyme of the steroid synthesis, cytochrome P450 side-chain cleavage enzyme (P450scc), as well as the key enzyme of progesterone synthesis, 3β-hydroxysteroid dehydrogenase (3β-HSD). Thus, it was well justified to consider that DRG neurons similarly are able to synthesize progesterone de novo from cholesterol. Because direct progesterone effects on axonal outgrowth in peripheral neurons have not been investigated up to now, the present study provides the first insights into the impact of exogenous progesterone on axonal outgrowth in DRG neurons. Our studies including microinjection and laser scanning microscopy demonstrate morphological changes especially in the neuronal growth cones after progesterone treatment. Furthermore, we were able to detect a distinctly enhanced motility only a few minutes after the start of progesterone treatment using time-lapse imaging. Investigation of the cytoskeletal distribution in the neuronal growth cone before, during, and after progesterone incubation revealed a rapid reorganization of actin filaments. To get a closer idea of the underlying receptor mechanisms, we further studied the expression of progesterone receptors in DRG neurons using RT-PCR and immunohistochemistry. Thus, we could demonstrate for the first time that classical progesterone receptor (PR) A and B and the recently described progesterone receptor membrane component 1 (PGRMC1) are expressed in DRG neurons. Antagonism of the classical progesterone receptors by mifepristone revealed that the observed progesterone effects are transmitted through PR-A and PR-B.
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Affiliation(s)
- Laura Olbrich
- Faculty of Medicine, Institute of Anatomy and Molecular Embryology, Ruhr-University Bochum, 44780 Bochum, Germany.
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Pitman MJ, Berzofsky CE, Alli O, Sharma S. Embryologic innervation of the rat laryngeal musculature-a model for investigation of recurrent laryngeal nerve reinnervation. Laryngoscope 2013; 123:3117-26. [DOI: 10.1002/lary.24216] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 04/19/2013] [Accepted: 04/19/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Michael J. Pitman
- New York Eye and Ear Infirmary, Department of Otolaryngology; Voice and Swallowing Institute; New York New York
| | - Craig E. Berzofsky
- Division of Laryngology; New York Eye and Ear Infirmary, Department of Otolaryngology; New York New York
| | - Opeyemi Alli
- New York Medical College, School of Medicine; Valhalla New York New York U.S.A
| | - Sansar Sharma
- Department of Cell Biology; New York Medical College; Valhalla New York
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Nerve growth factor-induced formation of axonal filopodia and collateral branches involves the intra-axonal synthesis of regulators of the actin-nucleating Arp2/3 complex. J Neurosci 2013; 32:17671-89. [PMID: 23223289 DOI: 10.1523/jneurosci.1079-12.2012] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nerve growth factor (NGF) induces collateral branching along sensory axons by promoting the formation of axonal filopodia dependent on the actin-nucleating Arp2/3 complex. This study shows that chicken embryonic sensory axons contain mRNAs for the actin-nucleating Arp2/3 complex activator WAVE1 and the complex stabilizer cortactin. NGF increases the axonal levels of WAVE1 and cortactin through localized protein synthesis even in axons isolated from the cell body. Inhibition of protein synthesis in severed axons impairs NGF-induced branching, the formation of axonal filopodia, and the initiation of Arp2/3-dependent axonal actin patches, which serve as precursors to the emergence of filopodia. Overexpression of WAVE1 or cortactin in axons not treated with NGF increased the rate of actin patch formation and the frequency of the emergence of filopodia from actin patches, respectively. Antisense inhibition of cortactin mRNA translation in isolated axons blocked NGF-induced filopodia. NGF also activated the Rac1 GTPase, which drives WAVE1 activity, in a protein synthesis-independent manner. Similarly, inhibition of protein synthesis did not impair the effects of NGF on the axonal microtubule cytoskeleton during branching. The effects of NGF on Rac1 activity and increases in axonal levels of WAVE1 and cortactin were both dependent on phosphoinositide 3-kinase (PI3K) signaling. Collectively, the data indicate that NGF promotes sensory axon branching through regulation of the actin cytoskeleton using both canonical signaling mechanisms and intra-axonal protein synthesis downstream of PI3K signaling. Finally, we present experimental evidence of axonal mRNA translation in sensory axons in the living embryonic spinal cord.
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Norris V, Amar P, Legent G, Ripoll C, Thellier M, Ovádi J. Sensor potency of the moonlighting enzyme-decorated cytoskeleton: the cytoskeleton as a metabolic sensor. BMC BIOCHEMISTRY 2013; 14:3. [PMID: 23398642 PMCID: PMC3577492 DOI: 10.1186/1471-2091-14-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 01/22/2013] [Indexed: 11/10/2022]
Abstract
Background There is extensive evidence for the interaction of metabolic enzymes with the eukaryotic cytoskeleton. The significance of these interactions is far from clear. Presentation of the hypothesis In the cytoskeletal integrative sensor hypothesis presented here, the cytoskeleton senses and integrates the general metabolic activity of the cell. This activity depends on the binding to the cytoskeleton of enzymes and, depending on the nature of the enzyme, this binding may occur if the enzyme is either active or inactive but not both. This enzyme-binding is further proposed to stabilize microtubules and microfilaments and to alter rates of GTP and ATP hydrolysis and their levels. Testing the hypothesis Evidence consistent with the cytoskeletal integrative sensor hypothesis is presented in the case of glycolysis. Several testable predictions are made. There should be a relationship between post-translational modifications of tubulin and of actin and their interaction with metabolic enzymes. Different conditions of cytoskeletal dynamics and enzyme-cytoskeleton binding should reveal significant differences in local and perhaps global levels and ratios of ATP and GTP. The different functions of moonlighting enzymes should depend on cytoskeletal binding. Implications of the hypothesis The physical and chemical effects arising from metabolic sensing by the cytoskeleton would have major consequences on cell shape, dynamics and cell cycle progression. The hypothesis provides a framework that helps the significance of the enzyme-decorated cytoskeleton be determined.
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Affiliation(s)
- Vic Norris
- EA 3829, Faculté des Sciences de l'Université de Rouen, 76821, Mont Saint Aignan Cedex, France.
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Santiago-Medina M, Gregus KA, Gomez TM. PAK-PIX interactions regulate adhesion dynamics and membrane protrusion to control neurite outgrowth. J Cell Sci 2013; 126:1122-33. [PMID: 23321640 DOI: 10.1242/jcs.112607] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The roles of P21-activated kinase (PAK) in the regulation of axon outgrowth downstream of extracellular matrix (ECM) proteins are poorly understood. Here we show that PAK1-3 and PIX are expressed in the developing spinal cord and differentially localize to point contacts and filopodial tips within motile growth cones. Using a specific interfering peptide called PAK18, we found that axon outgrowth is robustly stimulated on laminin by partial inhibition of PAK-PIX interactions and PAK function, whereas complete inhibition of PAK function stalls axon outgrowth. Furthermore, modest inhibition of PAK-PIX stimulates the assembly and turnover of growth cone point contacts, whereas strong inhibition over-stabilizes adhesions. Point mutations within PAK confirm the importance of PIX binding. Together our data suggest that regulation of PAK-PIX interactions in growth cones controls neurite outgrowth by influencing the activity of several important mediators of actin filament polymerization and retrograde flow, as well as integrin-dependent adhesion to laminin.
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Affiliation(s)
- Miguel Santiago-Medina
- Department of Neuroscience, Neuroscience Training Program, University of Wisconsin, Madison, WI 53706, USA
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Gallo G. Mechanisms underlying the initiation and dynamics of neuronal filopodia: from neurite formation to synaptogenesis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 301:95-156. [PMID: 23317818 DOI: 10.1016/b978-0-12-407704-1.00003-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Filopodia are finger-like cellular protrusions found throughout the metazoan kingdom and perform fundamental cellular functions during development and cell migration. Neurons exhibit a wide variety of extremely complex morphologies. In the nervous system, filopodia underlie many major morphogenetic events. Filopodia have roles spanning the initiation and guidance of neuronal processes, axons and dendrites to the formation of synaptic connections. This chapter addresses the mechanisms of the formation and dynamics of neuronal filopodia. Some of the major lessons learned from the study of neuronal filopodia are (1) there are multiple mechanisms that can regulate filopodia in a context-dependent manner, (2) that filopodia are specialized subcellular domains, (3) that filopodia exhibit dynamic membrane recycling which also controls aspects of filopodial dynamics, (4) that neuronal filopodia contain machinery for the orchestration of the actin and microtubule cytoskeleton, and (5) localized protein synthesis contributes to neuronal filopodial dynamics.
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Affiliation(s)
- Gianluca Gallo
- Shriners Hospitals Pediatric Research Center, Center for Neural Repair and Rehabilitation, Department of Anatomy and Cell Biology, Temple University, Philadelphia, PA, USA.
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Severino V, Farina A, Colucci-D'Amato L, Reccia MG, Volpicelli F, Parente A, Chambery A. Secretome profiling of differentiated neural mes-c-myc A1 cell line endowed with stem cell properties. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:2385-95. [PMID: 23246712 DOI: 10.1016/j.bbapap.2012.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 11/30/2012] [Accepted: 12/04/2012] [Indexed: 10/27/2022]
Abstract
Neural stem cell proliferation and differentiation play a crucial role in the formation and wiring of neuronal connections forming neuronal circuits. During neural tissues development, a large diversity of neuronal phenotypes is produced from neural precursor cells. In recent years, the cellular and molecular mechanisms by which specific types of neurons are generated have been explored with the aim to elucidate the complex events leading to the generation of different phenotypes via distinctive developmental programs that control self-renewal, differentiation, and plasticity. The extracellular environment is thought to provide instructive influences that actively induce the production of specific neuronal phenotypes. In this work, the secretome profiling of differentiated neural mes-c-myc A1 (A1) cell line endowed with stem cell properties was analyzed by applying a shotgun LC-MS/MS approach. The results provide a list of secreted molecules with potential relevance for the functional and biological features characterizing the A1 neuronal phenotype. Proteins involved in biological processes closely related to nervous system development including neurites growth, differentiation of neurons and axonogenesis were identified. Among them, proteins belonging to extracellular matrix and cell-adhesion complexes as well as soluble factors with well established neurotrophic properties were detected. The presented work provides the basis to clarify the complex extracellular protein networks implicated in neuronal differentiation and in the acquisition of the neuronal phenotype. This article is part of a Special Issue entitled: An Updated Secretome.
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Affiliation(s)
- Valeria Severino
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, I-81100 Caserta, Italy
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Abstract
Cell adhesion molecules of the immunoglobulin-super-family (IgSF-CAMs) do not only have a physical effect, mediating merely attachment between cell surfaces. For navigating axons, IgSF-CAMs also exert an instructive impact: Upon activation, they elicit intracellular signalling cascades in the tip of the axon, the growth cone, which regulate in a spatio-temporally concerted action both speed and direction of the axon. Density and distribution of IgSF-CAMs in the growth cone plasma membrane play important roles for the activation of IgSF-CAMs, their clustering, and the adhesive forces they acquire, as well as for the local restriction and effective propagation of their intracellular signals.
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Darmellah A, Rayah A, Auger R, Cuif MH, Prigent M, Arpin M, Alcover A, Delarasse C, Kanellopoulos JM. Ezrin/radixin/moesin are required for the purinergic P2X7 receptor (P2X7R)-dependent processing of the amyloid precursor protein. J Biol Chem 2012; 287:34583-95. [PMID: 22891241 DOI: 10.1074/jbc.m112.400010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) can be cleaved by α-secretases in neural cells to produce the soluble APP ectodomain (sAPPα), which is neuroprotective. We have shown previously that activation of the purinergic P2X7 receptor (P2X7R) triggers sAPPα shedding from neural cells. Here, we demonstrate that the activation of ezrin, radixin, and moesin (ERM) proteins is required for the P2X7R-dependent proteolytic processing of APP leading to sAPPα release. Indeed, the down-regulation of ERM by siRNA blocked the P2X7R-dependent shedding of sAPPα. We also show that P2X7R stimulation triggered the phosphorylation of ERM. Thus, ezrin translocates to the plasma membrane to interact with P2X7R. Using specific pharmacological inhibitors, we established the order in which several enzymes trigger the P2X7R-dependent release of sAPPα. Thus, a Rho kinase and the MAPK modules ERK1/2 and JNK act upstream of ERM, whereas a PI3K activity is triggered downstream. For the first time, this work identifies ERM as major partners in the regulated non-amyloidogenic processing of APP.
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Affiliation(s)
- Amaria Darmellah
- Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS UMR 8619, France
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Beggs S, Alvares D, Moss A, Currie G, Middleton J, Salter MW, Fitzgerald M. A role for NT-3 in the hyperinnervation of neonatally wounded skin. Pain 2012; 153:2133-2139. [PMID: 22871470 PMCID: PMC3657181 DOI: 10.1016/j.pain.2012.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 05/10/2012] [Accepted: 07/06/2012] [Indexed: 12/31/2022]
Abstract
Neurotrophin-3 (NT-3) is a target-derived neurotrophic factor that regulates sensory neuronal survival and growth. Here we report that NT-3 plays a critical permissive role in cutaneous sensory nerve sprouting that contributes to pain and sensitivity following skin wounding in young animals. Sensory terminal sprouting in neonatally wounded dermis and epidermis is accompanied by increased NT-3 transcription, NT-3 protein levels, and NT-3 protein release 3-7 days post skin injury in newborn rats and mice. Functional blockade of NT-3 activity with specific antibodies greatly reduces sensory neurite outgrowth induced by wounded skin, but not by naïve skin, in dorsal root ganglion/skin co-cultures. The requirement for NT-3 for sensory terminal sprouting in vivo is confirmed by the absence of wound-induced hyperinnervation in heterozygous transgenic mice (NT-3(+/-)lacZ). We conclude that upregulation of NT-3 in neonatally wounded skin is a critical factor mediating the sensory nerve sprouting that underlies hypersensitivity and pain following skin injury.
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Affiliation(s)
- Simon Beggs
- Programme in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
- Corresponding author at: Programme in Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8. Tel.: +1 4168135021.
| | - Debie Alvares
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Andrew Moss
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Gillian Currie
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Jacqueta Middleton
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Michael W. Salter
- Programme in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Maria Fitzgerald
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
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Role of L1CAM for axon sprouting and branching. Cell Tissue Res 2012; 349:39-48. [DOI: 10.1007/s00441-012-1345-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/25/2012] [Indexed: 01/02/2023]
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Marsick BM, Roche FK, Letourneau PC. Repulsive axon guidance cues ephrin-A2 and slit3 stop protrusion of the growth cone leading margin concurrently with inhibition of ADF/cofilin and ERM proteins. Cytoskeleton (Hoboken) 2012; 69:496-505. [PMID: 22328420 DOI: 10.1002/cm.21016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 02/01/2012] [Indexed: 11/08/2022]
Abstract
Axonal growth cones turn away from repulsive guidance cues. This may start with reduced protrusive motility in the region the growth cone leading margin that is closer to the source of repulsive cue. Using explants of E7 chick temporal retina, we examine the effects of two repulsive guidance cues, ephrin-A2 and slit3, on retinal ganglion cell growth cone protrusive activity, total F-actin, free F-actin barbed ends, and the activities (phosphorylation states) of actin regulatory proteins, ADF/cofilin and ezrin, radixin, moesin (ERM) proteins. Ephrin-A2 rapidly stops protrusive activity simultaneously with reducing F-actin, free barbed ends and the activities of ADF/cofilin and ERM proteins. Slit3 also stops protrusion and reduces the activities of ADF/cofilin and ERM proteins. We interpret these results as indicating that repulsive guidance cues inhibit actin polymerization and actin-membrane linkage to stop protrusive activity. Retrograde F-actin flow withdraws actin to the C-domain, where F-actin bundles interact with myosin II to generate contractile forces that can collapse and retract the growth cone. Our results suggest that common mechanisms are used by repulsive guidance cue to disable growth cone motility and remodel growing axon terminals.
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Affiliation(s)
- Bonnie M Marsick
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
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