101
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Gramlich MW, Balseiro-Gómez S, Tabei SMA, Parkes M, Yogev S. Distinguishing synaptic vesicle precursor navigation of microtubule ends with a single rate constant model. Sci Rep 2021; 11:3444. [PMID: 33564025 PMCID: PMC7873188 DOI: 10.1038/s41598-021-82836-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/25/2021] [Indexed: 11/09/2022] Open
Abstract
Axonal motor driven cargo utilizes the microtubule cytoskeleton in order to direct cargo, such as synaptic vesicle precursors (SVP), to where they are needed. This transport requires vesicles to travel up to microns in distance. It has recently been observed that finite microtubule lengths can act as roadblocks inhibiting SVP and increasing the time required for transport. SVPs reach the end of a microtubule and pause until they can navigate to a neighboring microtubule in order to continue transport. The mechanism(s) by which axonal SVPs navigate the end of a microtubule in order to continue mobility is unknown. In this manuscript we model experimentally observed vesicle pausing at microtubule ends in C. elegans. We show that a single rate-constant model reproduces the time SVPs pause at MT-ends. This model is based on the time an SVP must detach from its current microtubule and re-attach to a neighboring microtubule. We show that vesicle pause times are different for anterograde and retrograde motion, suggesting that vesicles utilize different proteins at plus and minus end sites. Last, we show that vesicles do not likely utilize a tug-of-war like mechanism and reverse direction in order to navigate microtubule ends.
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Affiliation(s)
- M W Gramlich
- Department of Physics, Auburn University, Auburn, AL, USA.
| | - S Balseiro-Gómez
- Departments of Neuroscience and Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - S M Ali Tabei
- Department of Physics, University of Northern Iowa, Cedar Falls, IA, USA
| | - M Parkes
- Department of Physics, Auburn University, Auburn, AL, USA
| | - S Yogev
- Departments of Neuroscience and Cell Biology, Yale School of Medicine, New Haven, CT, USA
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102
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Díaz-Martín RD, Valencia-Hernández JD, Betancourt-Lozano M, Yáñez-Rivera B. Changes in microtubule stability in zebrafish ( Danio rerio) embryos after glyphosate exposure. Heliyon 2021; 7:e06027. [PMID: 33532646 PMCID: PMC7829154 DOI: 10.1016/j.heliyon.2021.e06027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 11/09/2020] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Glyphosate, the most commonly used pesticide worldwide, blocks aromatic amino acid biosynthetic pathways and inhibits growth in plants. Although the specific mode of action of glyphosate in animals remains unclear, adverse effects during embryonic development have been reported, including epiboly delays, morphological alterations, and changes in central nervous system development and cardiogenesis. In this study, we suggest a possible toxicity mechanism for this herbicide related to changes in microtubule stability, which could alter the distribution and dynamics of cytoskeleton components. Using zebrafish embryos to evaluate in vivo effects of glyphosate exposure (5, 10, and 50 μg/ml), we found significant reductions in the levels of acetylated α-tubulin (50 μg/ml) and in the polymeric tubulin percentage in zebrafish embryos that had been exposed to 10 and 50 μg/ml glyphosate, without any changes in either the expression patterns of α-tubulin or the stability of actin filaments. These results indicate that high concentrations of glyphosate were associated with reduced levels of acetylated α-tubulin and altered microtubule stability, which may explain some of the neurotoxic and cardiotoxic effects that have been attributed to this herbicide.
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Affiliation(s)
- Rubén D Díaz-Martín
- Centro de Investigación en Alimentación y Desarrollo, A. C., Av. Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82100, Mexico
| | - Jesús D Valencia-Hernández
- Centro de Investigación en Alimentación y Desarrollo, A. C., Av. Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82100, Mexico
| | - Miguel Betancourt-Lozano
- Centro de Investigación en Alimentación y Desarrollo, A. C., Av. Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82100, Mexico
| | - Beatriz Yáñez-Rivera
- Centro de Investigación en Alimentación y Desarrollo, A. C., Av. Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82100, Mexico.,Consejo Nacional de Ciencia y Tecnología, Av. Insurgentes Sur 1582, Ciudad de México, 03940, Mexico
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103
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Valencia RG, Mihailovska E, Winter L, Bauer K, Fischer I, Walko G, Jorgacevski J, Potokar M, Zorec R, Wiche G. Plectin dysfunction in neurons leads to tau accumulation on microtubules affecting neuritogenesis, organelle trafficking, pain sensitivity and memory. Neuropathol Appl Neurobiol 2021; 47:73-95. [PMID: 32484610 PMCID: PMC7891324 DOI: 10.1111/nan.12635] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 05/19/2020] [Indexed: 12/26/2022]
Abstract
AIMS Plectin, a universally expressed multi-functional cytolinker protein, is crucial for intermediate filament networking, including crosstalk with actomyosin and microtubules. In addition to its involvement in a number of diseases affecting skin, skeletal muscle, heart, and other stress-exposed tissues, indications for a neuropathological role of plectin have emerged. Having identified P1c as the major isoform expressed in neural tissues in previous studies, our aim for the present work was to investigate whether, and by which mechanism(s), the targeted deletion of this isoform affects neuritogenesis and proper nerve cell functioning. METHODS For ex vivo phenotyping, we used dorsal root ganglion and hippocampal neurons derived from isoform P1c-deficient and plectin-null mice, complemented by in vitro experiments using purified proteins and cell fractions. To assess the physiological significance of the phenotypic alterations observed in P1c-deficient neurons, P1c-deficient and wild-type littermate mice were subjected to standard behavioural tests. RESULTS We demonstrate that P1c affects axonal microtubule dynamics by isoform-specific interaction with tubulin. P1c deficiency in neurons leads to altered dynamics of microtubules and excessive association with tau protein, affecting neuritogenesis, neurite branching, growth cone morphology, and translocation and directionality of movement of vesicles and mitochondria. On the organismal level, we found P1c deficiency manifesting as impaired pain sensitivity, diminished learning capabilities and reduced long-term memory of mice. CONCLUSIONS Revealing a regulatory role of plectin scaffolds in microtubule-dependent nerve cell functions, our results have potential implications for cytoskeleton-related neuropathies.
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Affiliation(s)
- R. G. Valencia
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Present address:
Department of ImmunologyUniversity Children’s Hospital ZurichZurichSwitzerland
| | - E. Mihailovska
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Present address:
AFFiRiS AGViennaAustria
| | - L. Winter
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Neuromuscular Research DepartmentCenter for Anatomy and Cell BiologyMedical University of ViennaViennaAustria
| | - K. Bauer
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
| | - I. Fischer
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
| | - G. Walko
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Present address:
Department of Biology and BiochemistryUniversity of BathBathUK
| | - J. Jorgacevski
- Laboratory of Neuroendocrinology – Molecular Cell PhysiologyFaculty of MedicineInstitute of PathophysiologyUniversity of LjubljanaLjubljanaSlovenia
- Celica Biomedical SloveniaLjubljanaSlovenia
| | - M. Potokar
- Laboratory of Neuroendocrinology – Molecular Cell PhysiologyFaculty of MedicineInstitute of PathophysiologyUniversity of LjubljanaLjubljanaSlovenia
- Celica Biomedical SloveniaLjubljanaSlovenia
| | - R. Zorec
- Laboratory of Neuroendocrinology – Molecular Cell PhysiologyFaculty of MedicineInstitute of PathophysiologyUniversity of LjubljanaLjubljanaSlovenia
- Celica Biomedical SloveniaLjubljanaSlovenia
| | - G. Wiche
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
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104
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Niceforo A, Marioli C, Colasuonno F, Petrini S, Massey K, Tartaglia M, Bertini E, Moreno S, Compagnucci C. Altered cytoskeletal arrangement in induced pluripotent stem cells (iPSCs) and motor neurons from patients with riboflavin transporter deficiency. Dis Model Mech 2021; 14:dmm.046391. [PMID: 33468503 PMCID: PMC7927654 DOI: 10.1242/dmm.046391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/05/2021] [Indexed: 12/28/2022] Open
Abstract
The cytoskeletal network plays a crucial role in differentiation, morphogenesis, function and homeostasis of the nervous tissue, so that alterations in any of its components may lead to neurodegenerative diseases. Riboflavin transporter deficiency (RTD), a childhood-onset disorder characterized by degeneration of motor neurons (MNs), is caused by biallelic mutations in genes encoding the human riboflavin (RF) transporters. In a patient- specific induced Pluripotent Stem Cells (iPSCs) model of RTD, we recently demonstrated altered cell-cell contacts, energy dysmetabolism and redox imbalance.The present study focusses on cytoskeletal composition and dynamics associated to RTD, utilizing patients' iPSCs and derived MNs. Abnormal expression and distribution of α- and β-tubulin (α- and β-TUB), as well as imbalanced tyrosination of α-TUB, accompanied by impaired ability to repolymerize after nocodazole treatment, were found in RTD patient-derived iPSCs. Following differentiation, MNs showed consistent changes in TUB content, which was associated with abnormal morphofunctional features, such as neurite length and Ca++ homeostasis, suggesting impaired differentiation.Beneficial effects of RF supplementation, alone or in combination with the antioxidant molecule N-acetyl-cystine (NAC), were assessed. RF administration resulted in partially improved cytoskeletal features in patients' iPSCs and MNs, suggesting that redundancy of transporters may rescue cell functionality in the presence of adequate concentrations of the vitamin. Moreover, supplementation with NAC was demonstrated to be effective in restoring all the considered parameters, when used in combination with RF, thus supporting the therapeutic use of both compounds.
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Affiliation(s)
- Alessia Niceforo
- Department of Science, Laboratorio Interdipartimentale di Microscopia Elettronica, University Roma Tre, Rome 00146, Italy
- Department of Neuroscience, Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Chiara Marioli
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Fiorella Colasuonno
- Department of Science, Laboratorio Interdipartimentale di Microscopia Elettronica, University Roma Tre, Rome 00146, Italy
- Department of Neuroscience, Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Keith Massey
- Science Director, Cure RTD Foundation, 6228 Northaven Road, Dallas, TX 75230, USA
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Enrico Bertini
- Department of Neuroscience, Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Sandra Moreno
- Department of Science, Laboratorio Interdipartimentale di Microscopia Elettronica, University Roma Tre, Rome 00146, Italy
| | - Claudia Compagnucci
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
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105
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Habicht J, Mooneyham A, Hoshino A, Shetty M, Zhang X, Emmings E, Yang Q, Coombes C, Gardner MK, Bazzaro M. UNC-45A breaks the microtubule lattice independently of its effects on non-muscle myosin II. J Cell Sci 2021; 134:jcs.248815. [PMID: 33262310 DOI: 10.1242/jcs.248815] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022] Open
Abstract
In invertebrates, UNC-45 regulates myosin stability and functions. Vertebrates have two distinct isoforms of the protein: UNC-45B, expressed in muscle cells only, and UNC-45A, expressed in all cells and implicated in regulating both non-muscle myosin II (NMII)- and microtubule (MT)-associated functions. Here, we show that, in vitro and in human and rat cells, UNC-45A binds to the MT lattice, leading to MT bending, breakage and depolymerization. Furthermore, we show that UNC-45A destabilizes MTs independent of its C-terminal NMII-binding domain and even in the presence of the NMII inhibitor blebbistatin. These findings identified UNC-45A as a novel type of MT-severing protein with a dual non-mutually exclusive role in regulating NMII activity and MT stability. Because many human diseases, from cancer to neurodegenerative diseases, are caused by or associated with deregulation of MT stability, our findings have profound implications in the biology of MTs, as well as the biology of human diseases and possible therapeutic implications for their treatment.This article has an associated First Person interview with the joint first authors of the paper.
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Affiliation(s)
- Juri Habicht
- Bradenburg Medical School - Theodor Fontane, Neuruppin 16816, Germany.,Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Ashley Mooneyham
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Asumi Hoshino
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mihir Shetty
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Xiaonan Zhang
- Bradenburg Medical School - Theodor Fontane, Neuruppin 16816, Germany.,Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Edith Emmings
- Bradenburg Medical School - Theodor Fontane, Neuruppin 16816, Germany
| | - Qing Yang
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Courtney Coombes
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Melissa K Gardner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Martina Bazzaro
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, USA
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106
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Bora G, Hensel N, Rademacher S, Koyunoğlu D, Sunguroğlu M, Aksu-Mengeş E, Balcı-Hayta B, Claus P, Erdem-Yurter H. Microtubule-associated protein 1B dysregulates microtubule dynamics and neuronal mitochondrial transport in spinal muscular atrophy. Hum Mol Genet 2021; 29:3935-3944. [PMID: 33410474 DOI: 10.1093/hmg/ddaa275] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating childhood disease primarily affecting lower motoneurons in the spinal cord. SMA is caused by the loss of functional survival of motoneuron (SMN) protein, leading to structural and functional alterations of the cytoskeleton in motoneurons and other cells. Loss of SMN results in impairments of microtubule architecture, but the underlying mechanisms are not completely understood. In this study, we mechanistically analyzed the effects of SMN deficiency on microtubules, demonstrating a reduced stability together with a reduction in alpha tubulin detyrosination. This was caused by increased levels of microtubule-associated protein 1B and tubulin tyrosine ligase, resulting in mitochondrial mislocalization in SMA. Our findings suggest that altered tubulin post-translational modifications and microtubule-associated proteins are involved in the pathomechanisms of SMA, such as an impaired axonal transport of mitochondria.
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Affiliation(s)
- Gamze Bora
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - Niko Hensel
- Institute of Neuroanatomy and Cell Biology, OE 4140, Hannover Medical School, Hannover 30625, Germany.,Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Sebastian Rademacher
- Institute of Neuroanatomy and Cell Biology, OE 4140, Hannover Medical School, Hannover 30625, Germany
| | - Dila Koyunoğlu
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - Merve Sunguroğlu
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - Evrim Aksu-Mengeş
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - Burcu Balcı-Hayta
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, OE 4140, Hannover Medical School, Hannover 30625, Germany.,Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Hayat Erdem-Yurter
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
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107
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Duquette A, Pernègre C, Veilleux Carpentier A, Leclerc N. Similarities and Differences in the Pattern of Tau Hyperphosphorylation in Physiological and Pathological Conditions: Impacts on the Elaboration of Therapies to Prevent Tau Pathology. Front Neurol 2021; 11:607680. [PMID: 33488502 PMCID: PMC7817657 DOI: 10.3389/fneur.2020.607680] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/07/2020] [Indexed: 12/20/2022] Open
Abstract
Tau protein, a neuronal microtubule-associated protein, becomes hyperphosphorylated in several neurodegenerative diseases called tauopathies. Hyperphosphorylation of tau is correlated to its redistribution from the axon to the somato-dendritic compartment at early stages of tauopathies. Interestingly, tau hyperphosphorylation begins in different regions of the brain in each tauopathy. In some regions, both neurons and glial cells develop tau hyperphosphorylation. Tau hyperphosphorylation is also observed in physiological conditions such as hibernation and brain development. In the first section of present article, we will review the spatiotemporal and cellular distribution of hyperphosphorylated tau in the most frequent tauopathies. In the second section, we will compare the pattern of tau hyperphosphorylation in physiological and pathological conditions and discuss the sites that could play a pivotal role in the conversion of non-toxic to toxic forms of hyperphosphorylated tau. Furthermore, we will discuss the role of hyperphosphorylated tau in physiological and pathological conditions and the fact that tau hyperphosphorylation is reversible in physiological conditions but not in a pathological ones. In the third section, we will speculate how the differences and similarities between hyperphosphorylated tau in physiological and pathological conditions could impact the elaboration of therapies to prevent tau pathology. In the fourth section, the different therapeutic approaches using tau as a direct or indirect therapeutic target will be presented.
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Affiliation(s)
- Antoine Duquette
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, QC, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Camille Pernègre
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, QC, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Ariane Veilleux Carpentier
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, QC, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Nicole Leclerc
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, QC, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
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108
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Yurinskaya MM, Garbuz DG, Afanasiev VN, Evgen’ev MB, Vinokurov MG. Effects of the Hydrogen Sulfide Donor GYY4137 and HSP70 Protein on the Activation of SH-SY5Y Cells by Lipopolysaccharide. Mol Biol 2021. [DOI: 10.1134/s002689332006014x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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109
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110
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Chronic neuronal activation increases dynamic microtubules to enhance functional axon regeneration after dorsal root crush injury. Nat Commun 2020; 11:6131. [PMID: 33257677 PMCID: PMC7705672 DOI: 10.1038/s41467-020-19914-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 11/05/2020] [Indexed: 12/26/2022] Open
Abstract
After a dorsal root crush injury, centrally-projecting sensory axons fail to regenerate across the dorsal root entry zone (DREZ) to extend into the spinal cord. We find that chemogenetic activation of adult dorsal root ganglion (DRG) neurons improves axon growth on an in vitro model of the inhibitory environment after injury. Moreover, repeated bouts of daily chemogenetic activation of adult DRG neurons for 12 weeks post-crush in vivo enhances axon regeneration across a chondroitinase-digested DREZ into spinal gray matter, where the regenerating axons form functional synapses and mediate behavioral recovery in a sensorimotor task. Neuronal activation-mediated axon extension is dependent upon changes in the status of tubulin post-translational modifications indicative of highly dynamic microtubules (as opposed to stable microtubules) within the distal axon, illuminating a novel mechanism underlying stimulation-mediated axon growth. We have identified an effective combinatory strategy to promote functionally-relevant axon regeneration of adult neurons into the CNS after injury.
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111
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Lin CH, Lin HY, Fang JM, Chen CC. A dual inhibitor targeting HMG-CoA reductase and histone deacetylase mitigates neurite degeneration in LRRK2-G2019S parkinsonism. Aging (Albany NY) 2020; 12:25581-25598. [PMID: 33231564 PMCID: PMC7803522 DOI: 10.18632/aging.104165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/27/2020] [Indexed: 06/11/2023]
Abstract
Parkinson's disease (PD) is among the most common neurodegenerative disorders, and its etiology involves both genetic and environmental factors. The leucine-rich repeat kinase (LRRK2) G2019S mutation is the most common genetic cause of familial and sporadic PD. Current treatment is limited to dopaminergic supplementation, as no disease-modifying therapy is available yet. Recent evidence reveals that HMG-CoA reductase (HMGR) inhibitors (statins) exert neuroprotection through anti-neuroinflammatory effects, and histone deacetylase (HDAC) inhibitors mitigate neurodegeneration by promoting the transcription of neuronal survival factors. We designed and synthesized a dual inhibitor, statin hydroxamate JMF3086, that simultaneously inhibits HMGR and HDAC, and examined its neuroprotective effects on LRRK2-G2019S parkinsonism. JMF3086 restored dopaminergic neuron loss in aged LRRK2-G2019S flies and rescued neurite degeneration in primary hippocampal and dopaminergic neurons isolated from transgenic LRRK2-G2019S mice. The molecular mechanisms included downregulation of ERK1/2 phosphorylation, increased anti-apoptotic Akt phosphorylation, and inhibition of GSK3β activity to maintain cytoskeletal stability in stably transfected LRRK2-G2019S SH-SY5Y human dopaminergic cells. JMF3086 also promoted a-tubulin acetylation and kinesin-1 expression, facilitating antegrade mitochondrial transport in axons. Our findings demonstrate that JMF3086 exerted beneficial effects on restoring LRRK2-G2019S neurite degeneration by maintaining microtubule stability. This dual-target compound may be a promising mechanism-based therapy for PD.
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Affiliation(s)
- Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Han-Yi Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Jim-Min Fang
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Ching-Chow Chen
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
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112
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Alberca CD, Papale LA, Madrid A, Gianatiempo O, Cánepa ET, Alisch RS, Chertoff M. Perinatal protein malnutrition results in genome-wide disruptions of 5-hydroxymethylcytosine at regions that can be restored to control levels by an enriched environment. Epigenetics 2020; 16:1085-1101. [PMID: 33172347 DOI: 10.1080/15592294.2020.1841871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Maternal malnutrition remains one of the major adversities affecting brain development and long-term mental health outcomes, increasing the risk to develop anxiety and depressive disorders. We have previously shown that malnutrition-induced anxiety-like behaviours can be rescued by a social and sensory stimulation (enriched environment) in male mice. Here, we expand these findings to adult female mice and profiled genome-wide ventral hippocampal 5hmC levels related to malnutrition-induced anxiety-like behaviours and their rescue by an enriched environment. This approach revealed 508 differentially hydroxymethylated genes associated with protein malnutrition and that several genes (N = 34) exhibited a restored 5hmC abundance to control levels following exposure to an enriched environment, including genes involved in neuronal functions like dendrite outgrowth, axon guidance, and maintenance of neuronal circuits (e.g. Fltr3, Itsn1, Lman1, Lsamp, Nav, and Ror1) and epigenetic mechanisms (e.g. Hdac9 and Dicer1). Sequence motif predictions indicated that 5hmC may be modulating the binding of transcription factors for several of these transcripts, suggesting a regulatory role for 5hmC in response to perinatal malnutrition and exposure to an enriched environment. Together, these findings establish a role for 5hmC in early-life malnutrition and reveal genes linked to malnutrition-induced anxious behaviours that are mitigated by an enriched environment.
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Affiliation(s)
- Carolina D Alberca
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Laboratorio de Neuroepigenetica, Buenos Aires, Argentina
| | - Ligia A Papale
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Andy Madrid
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA.,Neuroscience Training Program, University of Wisconsin, Madison, WI, USA
| | - Octavio Gianatiempo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Laboratorio de Neuroepigenetica, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales - CONICET (IQUIBICEN), Buenos Aires, Argentina
| | - Eduardo T Cánepa
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Laboratorio de Neuroepigenetica, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales - CONICET (IQUIBICEN), Buenos Aires, Argentina
| | - Reid S Alisch
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Mariela Chertoff
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Laboratorio de Neuroepigenetica, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales - CONICET (IQUIBICEN), Buenos Aires, Argentina
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113
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Kuo YW, Howard J. Cutting, Amplifying, and Aligning Microtubules with Severing Enzymes. Trends Cell Biol 2020; 31:50-61. [PMID: 33183955 PMCID: PMC7749064 DOI: 10.1016/j.tcb.2020.10.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/12/2020] [Accepted: 10/15/2020] [Indexed: 02/08/2023]
Abstract
Microtubule-severing enzymes - katanin, spastin, fidgetin - are related AAA-ATPases that cut microtubules into shorter filaments. These proteins, also called severases, are involved in a wide range of cellular processes including cell division, neuronal development, and tissue morphogenesis. Paradoxically, severases can amplify the microtubule cytoskeleton and not just destroy it. Recent work on spastin and katanin has partially resolved this paradox by showing that these enzymes are strong promoters of microtubule growth. Here, we review recent structural and biophysical advances in understanding the molecular mechanisms of severing and growth promotion that provide insight into how severing enzymes shape microtubule networks.
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Affiliation(s)
- Yin-Wei Kuo
- Department of Chemistry, Yale University, New Haven, CT 06511, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Jonathon Howard
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA.
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114
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Fourel G, Boscheron C. Tubulin mutations in neurodevelopmental disorders as a tool to decipher microtubule function. FEBS Lett 2020; 594:3409-3438. [PMID: 33064843 DOI: 10.1002/1873-3468.13958] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 01/08/2023]
Abstract
Malformations of cortical development (MCDs) are a group of severe brain malformations associated with intellectual disability and refractory childhood epilepsy. Human missense heterozygous mutations in the 9 α-tubulin and 10 β-tubulin isoforms forming the heterodimers that assemble into microtubules (MTs) were found to cause MCDs. However, how a single mutated residue in a given tubulin isoform can perturb the entire microtubule population in a neuronal cell remains a crucial question. Here, we examined 85 MCD-associated tubulin mutations occurring in TUBA1A, TUBB2, and TUBB3 and their location in a three-dimensional (3D) microtubule cylinder. Mutations hitting residues exposed on the outer microtubule surface are likely to alter microtubule association with partners, while alteration of intradimer contacts may impair dimer stability and straightness. Other types of mutations are predicted to alter interdimer and lateral contacts, which are responsible for microtubule cohesion, rigidity, and dynamics. MCD-associated tubulin mutations surprisingly fall into all categories, thus providing unexpected insights into how a single mutation may impair microtubule function and elicit dominant effects in neurons.
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115
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Twelvetrees AE. The lifecycle of the neuronal microtubule transport machinery. Semin Cell Dev Biol 2020; 107:74-81. [DOI: 10.1016/j.semcdb.2020.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 01/08/2023]
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116
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A M, Latario CJ, Pickrell LE, Higgs HN. Lysine acetylation of cytoskeletal proteins: Emergence of an actin code. J Biophys Biochem Cytol 2020; 219:211455. [PMID: 33044556 PMCID: PMC7555357 DOI: 10.1083/jcb.202006151] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/26/2020] [Accepted: 09/02/2020] [Indexed: 02/06/2023] Open
Abstract
Reversible lysine acetylation of nuclear proteins such as histones is a long-established important regulatory mechanism for chromatin remodeling and transcription. In the cytoplasm, acetylation of a number of cytoskeletal proteins, including tubulin, cortactin, and the formin mDia2, regulates both cytoskeletal assembly and stability. More recently, acetylation of actin itself was revealed to regulate cytoplasmic actin polymerization through the formin INF2, with downstream effects on ER-to-mitochondrial calcium transfer, mitochondrial fission, and vesicle transport. This finding raises the possibility that actin acetylation, along with other post-translational modifications to actin, might constitute an "actin code," similar to the "histone code" or "tubulin code," controlling functional shifts to these central cellular proteins. Given the multiple roles of actin in nuclear functions, its modifications might also have important roles in gene expression.
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117
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Microtubule Dysfunction: A Common Feature of Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21197354. [PMID: 33027950 PMCID: PMC7582320 DOI: 10.3390/ijms21197354] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons are particularly susceptible to microtubule (MT) defects and deregulation of the MT cytoskeleton is considered to be a common insult during the pathogenesis of neurodegenerative disorders. Evidence that dysfunctions in the MT system have a direct role in neurodegeneration comes from findings that several forms of neurodegenerative diseases are associated with changes in genes encoding tubulins, the structural units of MTs, MT-associated proteins (MAPs), or additional factors such as MT modifying enzymes which modulating tubulin post-translational modifications (PTMs) regulate MT functions and dynamics. Efforts to use MT-targeting therapeutic agents for the treatment of neurodegenerative diseases are underway. Many of these agents have provided several benefits when tested on both in vitro and in vivo neurodegenerative model systems. Currently, the most frequently addressed therapeutic interventions include drugs that modulate MT stability or that target tubulin PTMs, such as tubulin acetylation. The purpose of this review is to provide an update on the relevance of MT dysfunctions to the process of neurodegeneration and briefly discuss advances in the use of MT-targeting drugs for the treatment of neurodegenerative disorders.
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118
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Tubulin modifying enzymes as target for the treatment oftau-related diseases. Pharmacol Ther 2020; 218:107681. [PMID: 32961263 DOI: 10.1016/j.pharmthera.2020.107681] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/09/2020] [Indexed: 01/17/2023]
Abstract
In the brain of patients with Alzheimer's disease (AD), the number and length of microtubules (MTs) are significantly and selectively reduced. MTs are involved in a wide range of cellular functions, and defects of the microtubular system have emerged as a unifying hypothesis for the heterogeneous and variable clinical presentations of AD. MTs orchestrate their numerous functions through the spatiotemporal regulation of the binding of specialised microtubule-associated proteins (MAPs) and molecular motors. Covalent posttranslational modifications (PTMs) on the tubulin C-termini that protrude at the surface of MTs regulate the binding of these effectors. In neurons, MAP tau is highly abundant and its abnormal dissociation from MTs in the axon, cellular mislocalization and hyperphosphorylation, are primary events leading to neuronal death. Consequently, compounds targeting tau phosphorylation or aggregation are currently evaluated but their clinical significance has not been demonstrated yet. In this review, we discuss the emerging link between tubulin PTMs and tau dysfunction. In neurons, high levels of glutamylation and detyrosination profoundly impact the physicochemical properties at the surface of MTs. Moreover, in patients with early-onset progressive neurodegeneration, deleterious mutations in enzymes involved in modifying MTs at the surface have recently been identified, underscoring the importance of this enzymatic machinery in neurology. We postulate that pharmacologically targeting the tubulin-modifying enzymes holds promise as therapeutic approach for the treatment of neurodegenerative diseases.
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119
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What Happened in the Hippocampal Axon in a Rat Model of Posttraumatic Stress Disorder. Cell Mol Neurobiol 2020; 42:723-737. [PMID: 32930942 DOI: 10.1007/s10571-020-00960-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/03/2020] [Indexed: 01/01/2023]
Abstract
Studies from postmortem and animal models have revealed altered synapse morphology and function in the brain of posttraumatic stress disorder (PTSD). And the effects of PTSD on dendrites and spines have been reported, however, the effection on axon include microtubule (MT) and synaptic vesicles of presynaptic elements remains unknown. Hippocampus is involved in abnormal memory in PTSD. In the present study, we used the single prolonged stress (SPS) model to mimic PTSD. Quantitative real-time polymerase chain reaction (RT-qPCR) and high-throughput sequencing (GSE153081) were utilized to analyze differentially expressed genes (DEGs) in the hippocampus of control and SPS rats. Immunofluorescence and western blotting were performed to examine change in axon-related proteins. Synaptic function was evaluated by measuring miniature excitatory postsynaptic currents (mEPSCs). RNA-sequencing analysis revealed 230 significantly DEGs between the control and SPS groups. Gene Ontology analysis revealed upregulation in axonemal assembly, MT formation, or movement, but downregulation in axon initial segment and synaptic vesicles fusion in the hippocampus of SPS rats. Increased expression in tau, β-tubulin MAP1B, KIF9, CCDC40, DNAH12 and decreased expression in p-tau, stathmin suggested SPS induced axon extension. Increased protein expression in VAMP, STX1A, Munc18-1 and decreased expression in synaptotagmin-1 suggested SPS induced more SNARE complex formation but decreased ability in synaptic vesicle fusion to presynaptic active zone membrane in the hippocampus of SPS rats. Further, low mEPSC frequency in SPS rats indicated dysfunction in presynaptic membrane. These results suggest that axon extension and synaptic vesicles fusion abnormality are involved in dysfunction of PTSD.
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120
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CAMSAP1 breaks the homeostatic microtubule network to instruct neuronal polarity. Proc Natl Acad Sci U S A 2020; 117:22193-22203. [PMID: 32839317 DOI: 10.1073/pnas.1913177117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The establishment of axon/dendrite polarity is fundamental for neurons to integrate into functional circuits, and this process is critically dependent on microtubules (MTs). In the early stages of the establishment process, MTs in axons change dramatically with the morphological building of neurons; however, how the MT network changes are triggered is unclear. Here we show that CAMSAP1 plays a decisive role in the neuronal axon identification process by regulating the number of MTs. Neurons lacking CAMSAP1 form a multiple axon phenotype in vitro, while the multipolar-bipolar transition and radial migration are blocked in vivo. We demonstrate that the polarity regulator MARK2 kinase phosphorylates CAMSAP1 and affects its ability to bind to MTs, which in turn changes the protection of MT minus-ends and also triggers asymmetric distribution of MTs. Our results indicate that the polarized MT network in neurons is a decisive factor in establishing axon/dendritic polarity and is initially triggered by polarized signals.
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121
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Xiao Z, Yao Y, Wang Z, Tian Q, Wang J, Gu L, Li B, Zheng Q, Wu Y. Local Delivery of Taxol From FGL-Functionalized Self-Assembling Peptide Nanofiber Scaffold Promotes Recovery After Spinal Cord Injury. Front Cell Dev Biol 2020; 8:820. [PMID: 32974351 PMCID: PMC7471253 DOI: 10.3389/fcell.2020.00820] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/03/2020] [Indexed: 12/23/2022] Open
Abstract
Taxol has been clinically approved as an antitumor drug, and it exerts its antitumor effect through the excessive stabilization of microtubules in cancer cells. Recently, moderate microtubule stabilization by Taxol has been shown to efficiently promote neurite regeneration and functional recovery after spinal cord injury (SCI). However, the potential for the clinical translation of Taxol in treating SCI is limited by its side effects and low ability to cross the blood-spinal cord barrier (BSCB). Self-assembled peptide hydrogels have shown potential as drug carriers for the local delivery of therapeutic agents. We therefore hypothesized that the localized delivery of Taxol by a self-assembled peptide scaffold would promote axonal regeneration by stabilizing microtubules during the treatment of SCI. In the present study, the mechanistic functions of the Taxol-releasing system were clarified in vitro and in vivo using immunofluorescence labeling, histology and neurobehavioral analyses. Based on the findings from the in vitro study, Taxol released from a biological functionalized SAP nanofiber scaffold (FGLmx/Taxol) remained active and promoted neurite extension. In this study, we used a weight-drop contusion model to induce SCI at T9. The local delivery of Taxol from FGLmx/Taxol significantly decreased glial scarring and increased the number of nerve fibers compared with the use of FGLmx and 5% glucose. Furthermore, animals administered FGLmx/Taxol exhibited neurite preservation, smaller cavity dimensions, and decreased inflammation and demyelination. Thus, the local delivery of Taxol from FGLmx/Taxol was effective at promoting recovery after SCI and has potential as a new therapeutic strategy for SCI.
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Affiliation(s)
- Zhiyong Xiao
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingtao Yao
- Wuhan National Laboratory for Optoelectronics, Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiyu Wang
- Department of Pathology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Qing Tian
- Department of Orthopaedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jiedong Wang
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Li Gu
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bo Li
- Department of Orthopaedics, Beijing Jishuitan Hospital, Beijing, China
| | - Qixin Zheng
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yongchao Wu
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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122
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Activity-dependent neuroprotective protein (ADNP)-end-binding protein (EB) interactions regulate microtubule dynamics toward protection against tauopathy. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 177:65-90. [PMID: 33453943 DOI: 10.1016/bs.pmbts.2020.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The 1102-amino-acid activity-dependent neuroprotective protein (ADNP) was originally discovered by expression cloning through the immunological identification of its 8-amino-acid sequence NAPVSIPQ (NAP), constituting the smallest active neuroprotective fragment of the protein. ADNP expression is essential for brain formation and cognitive function and is dysregulated in a variety of neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, and schizophrenia). ADNP has been found to be mutated in autism, with an estimated prevalence of 0.17% (together, these autism cases now constitute ADNP syndrome cases) and our recent results showed somatic mutations in ADNP in Alzheimer's disease brains correlating with tauopathy. Furthermore, Adnp haploinsufficiency in mice causes an age-dependent reduction in cognitive functions coupled with tauopathy-like features such as an increased formation of tangle-like structures, defective axonal transport, and Tau hyperphosphorylation. ADNP and its derived peptides, NAP and SKIP, directly interact with end-binding proteins (EBs), which decorate plus-tips of the growing axonal cytoskeleton-microtubules (MTs). Functionally, NAP and SKIP are neuroprotective and stimulate axonal transport. Clinical trials have suggested the potential efficacy of NAP (davunetide, CP201) for improving cognitive performance/functional activities of daily living in amnestic mild cognitive impairment (aMCI) and schizophrenia patients, respectively. However, NAP was not found to be an effective treatment (though well-tolerated) for progressive supranuclear palsy (PSP) patients. Here we review the molecular mechanism of NAP activity on MTs and how NAP modulates the MT-Tau-EBs crosstalk. We offer a molecular explanation for the different protective potency of NAP in selected tauopathies (aMCI vs. PSP) expressing different ratios/pathologies of the alternatively spliced Tau mRNA and its resulting protein (aMCI expressing similar quantities of the dynamic Tau 3-MT binding isoform (Tau3R) and the Tau 4-MT binding isoform (Tau4R) and PSP enriched in Tau4R pathology). We reveal the direct effect of truncated ADNPs (resulting from de novo autism and newly discovered Alzheimer's disease-related somatic mutations) on MT dynamics. We show that the peptide SKIP affects MT dynamics and MT-Tau association. Since MT impairment is linked with neurodegenerative and neurodevelopmental conditions, the current study implicates a paucity/dysregulation of MT-interacting endogenous proteins, like ADNP, as a contributing mechanism and provides hope for NAP and SKIP as MT-modulating drug candidates.
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123
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Suciu SK, Caspary T. Cilia, neural development and disease. Semin Cell Dev Biol 2020; 110:34-42. [PMID: 32732132 DOI: 10.1016/j.semcdb.2020.07.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 12/16/2022]
Abstract
Neural development requires a series of cellular events starting with cell specification, proliferation, and migration. Subsequently, axons and dendrites project from the cell surface to form connections to other neurons, interneurons and glia. Anomalies in any one of these steps can lead to malformation or malfunction of the nervous system. Here we review the critical role the primary cilium plays in the fundamental steps of neurodevelopment. By highlighting human diseases caused by mutations in cilia-associated proteins, it is clear that cilia are essential to multiple neural processes. Furthermore, we explore whether additional aspects of cilia regulation, most notably post-translational modification of the tubulin scaffold in cilia, play underappreciated roles in neural development. Finally, we discuss whether cilia-associated proteins function outside the cilium in some aspects of neurodevelopment. These data underscore both the importance of cilia in the nervous system and some outstanding questions in the field.
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Affiliation(s)
- Sarah K Suciu
- Genetics and Molecular Biology Graduate Program, USA; Department of Human Genetics, Emory University, Atlanta, GA 30322, Georgia
| | - Tamara Caspary
- Department of Human Genetics, Emory University, Atlanta, GA 30322, Georgia.
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124
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Hertzler JI, Simonovitch SI, Albertson RM, Weiner AT, Nye DMR, Rolls MM. Kinetochore proteins suppress neuronal microtubule dynamics and promote dendrite regeneration. Mol Biol Cell 2020; 31:2125-2138. [PMID: 32673176 PMCID: PMC7530905 DOI: 10.1091/mbc.e20-04-0237-t] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Kinetochores connect centromeric chromatin to spindle microtubules during mitosis. Neurons are postmitotic, so it was surprising to identify transcripts of structural kinetochore (KT) proteins and regulatory chromosome passenger complex (CPC) and spindle assembly checkpoint (SAC) proteins in Drosophila neurons after dendrite injury. To test whether these proteins function during dendrite regeneration, postmitotic RNA interference (RNAi) was performed and dendrites or axons were removed using laser microsurgery. Reduction of KT, CPC, and SAC proteins decreased dendrite regeneration without affecting axon regeneration. To understand whether neuronal functions of these proteins rely on microtubules, we analyzed microtubule behavior in uninjured neurons. The number of growing plus, but not minus, ends increased in dendrites with reduced KT, CPC, and SAC proteins, while axonal microtubules were unaffected. Increased dendritic microtubule dynamics was independent of dual leucine zipper kinase (DLK)-mediated stress but was rescued by concurrent reduction of γ-tubulin, the core microtubule nucleation protein. Reduction of γ-tubulin also rescued dendrite regeneration in backgrounds containing kinetochore RNAi transgenes. We conclude that kinetochore proteins function postmitotically in neurons to suppress dendritic microtubule dynamics by inhibiting nucleation.
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Affiliation(s)
- James I Hertzler
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Samantha I Simonovitch
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Richard M Albertson
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802.,MSTP Program, Milton S. Hershey College of Medicine, Hershey, PA 17033
| | - Alexis T Weiner
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Derek M R Nye
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802.,MSTP Program, Milton S. Hershey College of Medicine, Hershey, PA 17033
| | - Melissa M Rolls
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
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125
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Rodemer W, Gallo G, Selzer ME. Mechanisms of Axon Elongation Following CNS Injury: What Is Happening at the Axon Tip? Front Cell Neurosci 2020; 14:177. [PMID: 32719586 PMCID: PMC7347967 DOI: 10.3389/fncel.2020.00177] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022] Open
Abstract
After an injury to the central nervous system (CNS), functional recovery is limited by the inability of severed axons to regenerate and form functional connections with appropriate target neurons beyond the injury. Despite tremendous advances in our understanding of the mechanisms of axon growth, and of the inhibitory factors in the injured CNS that prevent it, disappointingly little progress has been made in restoring function to human patients with CNS injuries, such as spinal cord injury (SCI), through regenerative therapies. Clearly, the large number of overlapping neuron-intrinsic and -extrinsic growth-inhibitory factors attenuates the benefit of neutralizing any one target. More daunting is the distances human axons would have to regenerate to reach some threshold number of target neurons, e.g., those that occupy one complete spinal segment, compared to the distances required in most experimental models, such as mice and rats. However, the difficulties inherent in studying mechanisms of axon regeneration in the mature CNS in vivo have caused researchers to rely heavily on extrapolation from studies of axon regeneration in peripheral nerve, or of growth cone-mediated axon development in vitro and in vivo. Unfortunately, evidence from several animal models, including the transected lamprey spinal cord, has suggested important differences between regeneration of mature CNS axons and growth of axons in peripheral nerve, or during embryonic development. Specifically, long-distance regeneration of severed axons may not involve the actin-myosin molecular motors that guide embryonic growth cones in developing axons. Rather, non-growth cone-mediated axon elongation may be required to propel injured axons in the mature CNS. If so, it may be necessary to use other experimental models to promote regeneration that is sufficient to contact a critical number of target neurons distal to a CNS lesion. This review examines the cytoskeletal underpinnings of axon growth, focusing on the elongating axon tip, to gain insights into how CNS axons respond to injury, and how this might affect the development of regenerative therapies for SCI and other CNS injuries.
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Affiliation(s)
- William Rodemer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Gianluca Gallo
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States.,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States.,Department of Neurology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
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126
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Mahmoodi N, Ai J, Ebrahimi‐Barough S, Hassannejad Z, Hasanzadeh E, Basiri A, Vaccaro AR, Rahimi‐Movaghar V. Microtubule stabilizer epothilone B as a motor neuron differentiation agent for human endometrial stem cells. Cell Biol Int 2020; 44:1168-1183. [DOI: 10.1002/cbin.11315] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/02/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Narges Mahmoodi
- Sina Trauma and Surgery Research Center, Sina HospitalTehran University of Medical Sciences Hasan‐Abad Square, Imam Khomeini Ave. Tehran 11365‐3876 Iran
| | - Jafar Ai
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in MedicineTehran University of Medical Sciences Number 88, Italy Street, Between Ghods Street and Vesal Shirazi Street Tehran 14177‐55469 Iran
| | - Somayeh Ebrahimi‐Barough
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in MedicineTehran University of Medical Sciences Number 88, Italy Street, Between Ghods Street and Vesal Shirazi Street Tehran 14177‐55469 Iran
| | - Zahra Hassannejad
- Pediatric Urology and Regenerative Medicine Research Center, Children's Medical Center, Pediatric Center of ExcellenceTehran University of Medical Sciences No. 62, Dr. Gharibs Street, Keshavarz Boulevard Tehran 1419733151 Iran
| | - Elham Hasanzadeh
- Department of Tissue Engineering, School of Advanced Technologies in MedicineMazandaran University of Medical Sciences Next to Tooba Medical Building, Khazar Boulevard Sari 48471‐91971 Iran
| | - Arefeh Basiri
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in MedicineTehran University of Medical Sciences Number 88, Italy Street, Between Ghods Street and Vesal Shirazi Street Tehran 14177‐55469 Iran
| | - Alexander R. Vaccaro
- Department of Orthopedic Surgery, Rothman InstituteThomas Jefferson University 1925 Chestnut Street, 5th Floor Philadelphia Pennsylvania 19107 USA
| | - Vafa Rahimi‐Movaghar
- Sina Trauma and Surgery Research Center, Sina HospitalTehran University of Medical Sciences Hasan‐Abad Square, Imam Khomeini Ave. Tehran 11365‐3876 Iran
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127
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Rolls MM, Thyagarajan P, Feng C. Microtubule dynamics in healthy and injured neurons. Dev Neurobiol 2020; 81:321-332. [PMID: 32291942 DOI: 10.1002/dneu.22746] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/22/2020] [Accepted: 04/08/2020] [Indexed: 12/28/2022]
Abstract
Most neurons must last a lifetime and their microtubule cytoskeleton is an important contributor to their longevity. Neurons have some of the most stable microtubules of all cells, but the tip of every microtubule remains dynamic and, although requiring constant GTP consumption, microtubules are always being rebuilt. While some ongoing level of rebuilding always occurs, overall microtubule stability can be modulated in response to injury and stress as well as the normal developmental process of pruning. Specific microtubule severing proteins act in different contexts to increase microtubule dynamicity and promote degeneration and pruning. After axon injury, complex changes in dynamics occur and these are important for both neuroprotection induced by injury and subsequent outgrowth of a new axon. Understanding how microtubule dynamics is modulated in different scenarios, as well as the impact of the changes in stability, is an important avenue to explore for development of strategies to promote neuroprotection and regeneration.
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Affiliation(s)
- Melissa M Rolls
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Pankajam Thyagarajan
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Chengye Feng
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
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128
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McElmurry K, Stone JE, Ma D, Lamoureux P, Zhang Y, Steidemann M, Fix L, Huang F, Miller KE, Suter DM. Dynein-mediated microtubule translocation powering neurite outgrowth in chick and Aplysia neurons requires microtubule assembly. J Cell Sci 2020; 133:133/8/jcs232983. [PMID: 32332091 DOI: 10.1242/jcs.232983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 03/02/2020] [Indexed: 12/22/2022] Open
Abstract
Previously, we have shown that bulk microtubule (MT) movement correlates with neurite elongation, and blocking either dynein activity or MT assembly inhibits both processes. However, whether the contributions of MT dynamics and dynein activity to neurite elongation are separate or interdependent is unclear. Here, we investigated the underlying mechanism by testing the roles of dynein and MT assembly in neurite elongation of Aplysia and chick neurites using time-lapse imaging, fluorescent speckle microscopy, super-resolution imaging and biophysical analysis. Pharmacologically inhibiting either dynein activity or MT assembly reduced neurite elongation rates as well as bulk and individual MT anterograde translocation. Simultaneously suppressing both processes did not have additive effects, suggesting a shared mechanism of action. Single-molecule switching nanoscopy revealed that inhibition of MT assembly decreased the association of dynein with MTs. Finally, inhibiting MT assembly prevented the rise in tension induced by dynein inhibition. Taken together, our results suggest that MT assembly is required for dynein-driven MT translocation and neurite outgrowth.
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Affiliation(s)
- Kristi McElmurry
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jessica E Stone
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Donghan Ma
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Phillip Lamoureux
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Yueyun Zhang
- Department of Statistics, Purdue University, West Lafayette, IN 47904, USA
| | - Michelle Steidemann
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Lucas Fix
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Fang Huang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Kyle E Miller
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA .,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA.,Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA.,Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
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129
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Matis M. The Mechanical Role of Microtubules in Tissue Remodeling. Bioessays 2020; 42:e1900244. [PMID: 32249455 DOI: 10.1002/bies.201900244] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/12/2020] [Indexed: 12/31/2022]
Abstract
During morphogenesis, tissues undergo extensive remodeling to get their final shape. Such precise sculpting requires the application of forces generated within cells by the cytoskeleton and transmission of these forces through adhesion molecules within and between neighboring cells. Within individual cells, microtubules together with actomyosin filaments and intermediate filaments form the composite cytoskeleton that controls cell mechanics during tissue rearrangements. While studies have established the importance of actin-based mechanical forces that are coupled via intercellular junctions, relatively little is known about the contribution of other cytoskeletal components such as microtubules to cell mechanics during morphogenesis. In this review the focus is on recent findings, highlighting the direct mechanical role of microtubules beyond its well-established role in trafficking and signaling during tissue formation.
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Affiliation(s)
- Maja Matis
- Institute of Cell Biology, Medical Faculty, University of Münster, Münster, 48149, Germany.,'Cells in Motion' Interfaculty Centre, University of Münster, Münster, 48149, Germany
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130
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Kwon Y, Jeon YW, Kwon M, Cho Y, Park D, Shin JE. βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway. PLoS One 2020; 15:e0230814. [PMID: 32251425 PMCID: PMC7135283 DOI: 10.1371/journal.pone.0230814] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/09/2020] [Indexed: 12/11/2022] Open
Abstract
Microtubules are a major cytoskeletal component of neurites, and the regulation of microtubule stability is essential for neurite morphogenesis. βPix (ARHGEF7) is a guanine nucleotide exchange factor for the small GTPases Rac1 and Cdc42, which modulate the organization of actin filaments and microtubules. βPix is expressed as alternatively spliced variants, including the ubiquitous isoform βPix-a and the neuronal isoforms βPix-b and βPix-d, but the function of the neuronal isoforms remains unclear. Here, we reveal the novel role of βPix neuronal isoforms in regulating tubulin acetylation and neurite outgrowth. At DIV4, hippocampal neurons cultured from βPix neuronal isoform knockout (βPix-NIKO) mice exhibit defects in neurite morphology and tubulin acetylation, a type of tubulin modification which often labels stable microtubules. Treating βPix-NIKO neurons with paclitaxel, which stabilizes the microtubules, or reintroducing either neuronal βPix isoform to the KO neurons overcomes the impairment in neurite morphology and tubulin acetylation, suggesting that neuronal βPix isoforms may promote microtubule stabilization during neurite development. βPix-NIKO neurons also exhibit lower phosphorylation levels for Stathmin1, a microtubule-destabilizing protein, at Ser16. Expressing either βPix neuronal isoform in the βPix-NIKO neurons restores Stathmin1 phosphorylation levels, with βPix-d having a greater effect than βPix-b. Furthermore, we find that the recovery of neurite length and Stathmin1 phosphorylation via βPix-d expression requires PAK kinase activity. Taken together, our study demonstrates that βPix-d regulates the phosphorylation of Stathmin1 in a PAK-dependent manner and that neuronal βPix isoforms promote tubulin acetylation and neurite morphogenesis during neuronal development.
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Affiliation(s)
- Younghee Kwon
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Ye Won Jeon
- Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Minjae Kwon
- Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Yongcheol Cho
- Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Dongeun Park
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jung Eun Shin
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
- Institute of Life Science and Biotechnology, Korea University, Seoul, Republic of Korea
- * E-mail:
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131
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Cuveillier C, Delaroche J, Seggio M, Gory-Fauré S, Bosc C, Denarier E, Bacia M, Schoehn G, Mohrbach H, Kulić I, Andrieux A, Arnal I, Delphin C. MAP6 is an intraluminal protein that induces neuronal microtubules to coil. SCIENCE ADVANCES 2020; 6:eaaz4344. [PMID: 32270043 PMCID: PMC7112752 DOI: 10.1126/sciadv.aaz4344] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/09/2020] [Indexed: 06/01/2023]
Abstract
Neuronal activities depend heavily on microtubules, which shape neuronal processes and transport myriad molecules within them. Although constantly remodeled through growth and shrinkage events, neuronal microtubules must be sufficiently stable to maintain nervous system wiring. This stability is somehow maintained by various microtubule-associated proteins (MAPs), but little is known about how these proteins work. Here, we show that MAP6, previously known to confer cold stability to microtubules, promotes growth. More unexpectedly, MAP6 localizes in the lumen of microtubules, induces the microtubules to coil into a left-handed helix, and forms apertures in the lattice, likely to relieve mechanical stress. These features have not been seen in microtubules before and could play roles in maintaining axonal width or providing flexibility in the face of compressive forces during development.
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Affiliation(s)
- Camille Cuveillier
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Julie Delaroche
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Maxime Seggio
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Sylvie Gory-Fauré
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Christophe Bosc
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Eric Denarier
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Maria Bacia
- Univ. Grenoble Alpes, CNRS, CEA, Institut for Structural Biology (IBS), 38000 Grenoble, France
| | - Guy Schoehn
- Univ. Grenoble Alpes, CNRS, CEA, Institut for Structural Biology (IBS), 38000 Grenoble, France
| | - Hervé Mohrbach
- Laboratoire de Chimie et Physique Théorique, UMR 7019, Université de Lorraine
| | - Igor Kulić
- Institut Charles Sandron, CNRS-UdS, 67034 Strasbourg, France
| | - Annie Andrieux
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Isabelle Arnal
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Christian Delphin
- Univ. Grenoble Alpes, Inserm U1216, CEA, CNRS, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
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132
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Jakobs MAH, Franze K, Zemel A. Mechanical Regulation of Neurite Polarization and Growth: A Computational Study. Biophys J 2020; 118:1914-1920. [PMID: 32229314 DOI: 10.1016/j.bpj.2020.02.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 02/19/2020] [Accepted: 02/27/2020] [Indexed: 01/14/2023] Open
Abstract
The densely packed microtubule (MT) array found in neuronal cell projections (neurites) serves two fundamental functions simultaneously: it provides a mechanically stable track for molecular motor-based transport and produces forces that drive neurite growth. The local pattern of MT polarity along the neurite shaft has been found to differ between axons and dendrites. In axons, the neurons' dominating long projections, roughly 90% of the MTs orient with their rapidly growing plus end away from the cell body, whereas in vertebrate dendrites, their orientations are locally mixed. Molecular motors are known to be responsible for cytoskeletal ordering and force generation, but their collective function in the dense MT cytoskeleton of neurites remains elusive. We here hypothesized that both the polarity pattern of MTs along the neurite shaft and the shaft's global extension are simultaneously driven by molecular motor forces and should thus be regulated by the mechanical load acting on the MT array as a whole. To investigate this, we simulated cylindrical bundles of MTs that are cross-linked and powered by molecular motors by iteratively solving a set of force-balance equations. The bundles were subjected to a fixed load arising from actively generated tension in the actomyosin cortex enveloping the MTs. The magnitude of the load and the level of motor-induced connectivity between the MTs have been varied systematically. With an increasing load and decreasing motor-induced connectivity between MTs, the bundles became wider in cross section and extended more slowly, and the local MT orientational order was reduced. These results reveal two, to our knowledge, novel mechanical factors that may underlie the distinctive development of the MT cytoskeleton in axons and dendrites: the cross-linking level of MTs by motors and the load acting on this cytoskeleton during growth.
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Affiliation(s)
- Maximilian A H Jakobs
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Assaf Zemel
- Institute of Dental Sciences and Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Jerusalem, Israel.
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133
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Nishida T, Yoshimura R, Nishi R, Imoto Y, Endo Y. Application of ultra-high voltage electron microscope tomography to 3D imaging of microtubules in neurites of cultured PC12 cells. J Microsc 2020; 278:42-48. [PMID: 32133640 DOI: 10.1111/jmi.12885] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 02/14/2020] [Accepted: 03/02/2020] [Indexed: 11/28/2022]
Abstract
Electron tomography methods using the conventional transmission electron microscope have been widely used to investigate the three-dimensional distribution patterns of various cellular structures including microtubules in neurites. Because the penetrating power of electrons depends on the section thickness and accelerating voltage, conventional TEM, having acceleration voltages up to 200 kV, is limited to sample thicknesses of 0.2 µm or less. In this paper, we show that the ultra-high voltage electron microscope (UHVEM), employing acceleration voltages of higher than 1000 kV (1 MV), allowed distinct reconstruction of the three-dimensional array of microtubules in a 0.7-µm-thick neurite section. The detailed structure of microtubules was more clearly reconstructed from a 0.7-µm-thick section at an accelerating voltage of 1 MV compared with a 1.0 µm section at 2 MV. Furthermore, the entire distribution of each microtubule in a neurite could be reconstructed from serial-section UHVEM tomography. Application of optimised UHVEM tomography will provide new insights, bridging the gap between the structure and function of widely-distributed cellular organelles such as microtubules for neurite outgrowth. LAY DESCRIPTION: An optimal 3D visualisation of microtubule cytoskeleton using ultra-high voltage electron microscopy tomography The ultra-high voltage electron microscope (UHVEM) is able to visualise a micrometre-thick specimen at nanoscale spatial resolution because of the high-energy electron beam penetrating such a specimen. In this study, we determined the optimal conditions necessary for microtubule cytoskeleton imaging within 0.7-µm-thick section using a combination with UHVEM and electron tomography method. Our approach provides excellent 3D information about the complex arrangement of the individual microtubule filaments that make up the microtubule network.
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Affiliation(s)
- T Nishida
- Japan Textile Products Quality and Technology Center, Kobe, Hyogo, Japan
| | - R Yoshimura
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
| | - R Nishi
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka, Japan
| | - Y Imoto
- Japan Textile Products Quality and Technology Center, Kobe, Hyogo, Japan
| | - Y Endo
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
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134
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Meka DP, Scharrenberg R, Calderon de Anda F. Emerging roles of the centrosome in neuronal development. Cytoskeleton (Hoboken) 2020; 77:84-96. [DOI: 10.1002/cm.21593] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/16/2019] [Accepted: 01/04/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Durga Praveen Meka
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH)University Medical Center Hamburg‐Eppendorf Hamburg Germany
| | - Robin Scharrenberg
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH)University Medical Center Hamburg‐Eppendorf Hamburg Germany
| | - Froylan Calderon de Anda
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH)University Medical Center Hamburg‐Eppendorf Hamburg Germany
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135
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Calogero AM, Mazzetti S, Pezzoli G, Cappelletti G. Neuronal microtubules and proteins linked to Parkinson's disease: a relevant interaction? Biol Chem 2020; 400:1099-1112. [PMID: 31256059 DOI: 10.1515/hsz-2019-0142] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/24/2019] [Indexed: 12/13/2022]
Abstract
Neuronal microtubules are key determinants of cell morphology, differentiation, migration and polarity, and contribute to intracellular trafficking along axons and dendrites. Microtubules are strictly regulated and alterations in their dynamics can lead to catastrophic effects in the neuron. Indeed, the importance of the microtubule cytoskeleton in many human diseases is emerging. Remarkably, a growing body of evidence indicates that microtubule defects could be linked to Parkinson's disease pathogenesis. Only a few of the causes of the progressive neuronal loss underlying this disorder have been identified. They include gene mutations and toxin exposure, but the trigger leading to neurodegeneration is still unknown. In this scenario, the evidence showing that mutated proteins in Parkinson's disease are involved in the regulation of the microtubule cytoskeleton is intriguing. Here, we focus on α-Synuclein, Parkin and Leucine-rich repeat kinase 2 (LRRK2), the three main proteins linked to the familial forms of the disease. The aim is to dissect their interaction with tubulin and microtubules in both physiological and pathological conditions, in which these proteins are overexpressed, mutated or absent. We highlight the relevance of such an interaction and suggest that these proteins could trigger neurodegeneration via defective regulation of the microtubule cytoskeleton.
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Affiliation(s)
- Alessandra M Calogero
- Department of Biosciences, Università degli Studi di Milano, via Celoria 26, I-20133 Milan, Italy
| | - Samanta Mazzetti
- Department of Biosciences, Università degli Studi di Milano, via Celoria 26, I-20133 Milan, Italy.,Fondazione Grigioni per il Morbo di Parkinson, via Zuretti 35, I-20135 Milan, Italy
| | - Gianni Pezzoli
- Fondazione Grigioni per il Morbo di Parkinson, via Zuretti 35, I-20135 Milan, Italy.,Parkinson Institute, ASST "G.Pini-CTO", via Bignami 1, I-20133 Milan, Italy
| | - Graziella Cappelletti
- Department of Biosciences, Università degli Studi di Milano, via Celoria 26, I-20133 Milan, Italy.,Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, via Balzaretti, I-20133 Milan, Italy
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136
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A Role of Microtubules in Oligodendrocyte Differentiation. Int J Mol Sci 2020; 21:ijms21031062. [PMID: 32033476 PMCID: PMC7037135 DOI: 10.3390/ijms21031062] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/29/2020] [Accepted: 02/03/2020] [Indexed: 12/17/2022] Open
Abstract
Oligodendrocytes are specialized cells that myelinate axons in the central nervous system. Defects in oligodendrocyte function and failure to form or maintain myelin sheaths can cause a number of neurological disorders. Oligodendrocytes are differentiated from oligodendrocyte progenitor cells (OPCs), which extend several processes that contact, elaborate, and eventually wrap axonal segments to form multilayered myelin sheaths. These processes require extensive changes in the cytoarchitecture and must be regulated by reorganization of the cytoskeleton. Here, we established a simple protocol to isolate and differentiate mouse OPCs, and by using this method, we investigated a role of microtubules (MTs) in oligodendrocyte differentiation. Oligodendrocytes developed a complex network of MTs during differentiation, and treatment of differentiating oligodendrocytes with nanomolar concentrations of MT-targeting agents (MTAs) markedly affected oligodendrocyte survival and differentiation. We found that acute exposure to vincristine and nocodazole at early stages of oligodendrocyte differentiation markedly increased MT arborization and enhanced differentiation, whereas taxol and epothilone B treatment produced opposing outcomes. Furthermore, treatment of myelinating co-cultures of oligodendrocytes and neurons with nanomolar concentrations of MTAs at late stages of oligodendrocyte differentiation induced dysmyelination. Together, these results suggest that MTs play an important role in the survival, differentiation, and myelination of oligodendrocytes.
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137
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Clark JA, Chuckowree JA, Dyer MS, Dickson TC, Blizzard CA. Epothilone D alters normal growth, viability and microtubule dependent intracellular functions of cortical neurons in vitro. Sci Rep 2020; 10:918. [PMID: 31969604 PMCID: PMC6976590 DOI: 10.1038/s41598-020-57718-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/18/2019] [Indexed: 01/09/2023] Open
Abstract
Brain penetrant microtubule stabilising agents (MSAs) are being increasingly validated as potential therapeutic strategies for neurodegenerative diseases and traumatic injuries of the nervous system. MSAs are historically used to treat malignancies to great effect. However, this treatment strategy can also cause adverse off-target impacts, such as the generation of debilitating neuropathy and axonal loss. Understanding of the effects that individual MSAs have on neurons of the central nervous system is still incomplete. Previous research has revealed that aberrant microtubule stabilisation can perturb many neuronal functions, such as neuronal polarity, neurite outgrowth, microtubule dependant transport and overall neuronal viability. In the current study, we evaluate the dose dependant impact of epothilone D, a brain penetrant MSA, on both immature and relatively mature mouse cortical neurons in vitro. We show that epothilone D reduces the viability, growth and complexity of immature cortical neurons in a dose dependant manner. Furthermore, in relatively mature cortical neurons, we demonstrate that while cellularly lethal doses of epothilone D cause cellular demise, low sub lethal doses can also affect mitochondrial transport over time. Our results reveal an underappreciated mitochondrial disruption over a wide range of epothilone D doses and reiterate the importance of understanding the dosage, timing and intended outcome of MSAs, with particular emphasis on brain penetrant MSAs being considered to target neurons in disease and trauma.
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Affiliation(s)
- J A Clark
- Menzies Institute for Medical Research, University of Tasmania 17 Liverpool Street Hobart, Tasmania, 7000, Australia
| | - J A Chuckowree
- Menzies Institute for Medical Research, University of Tasmania 17 Liverpool Street Hobart, Tasmania, 7000, Australia
| | - M S Dyer
- Menzies Institute for Medical Research, University of Tasmania 17 Liverpool Street Hobart, Tasmania, 7000, Australia
| | - T C Dickson
- Menzies Institute for Medical Research, University of Tasmania 17 Liverpool Street Hobart, Tasmania, 7000, Australia
| | - C A Blizzard
- Menzies Institute for Medical Research, University of Tasmania 17 Liverpool Street Hobart, Tasmania, 7000, Australia.
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138
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RhoA-GTPase Modulates Neurite Outgrowth by Regulating the Expression of Spastin and p60-Katanin. Cells 2020; 9:cells9010230. [PMID: 31963385 PMCID: PMC7016723 DOI: 10.3390/cells9010230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/17/2022] Open
Abstract
RhoA-GTPase (RhoA) is widely regarded as a key molecular switch to inhibit neurite outgrowth by rigidifying the actin cytoskeleton. However, during neurite outgrowth, whether and how microtubule dynamics are regulated by RhoA remains to be elucidated. Herein, CT04 and Y27632 were used to inactivate RhoA and its downstream effector Rho-associated coiled coil-forming kinase (ROCK), while the RhoAQ63L lentiviral vector was utilized to overexpress the constitutively activated RhoA in dorsal root ganglion (DRG) neurons or neuronal differentiated PC12 cells. The current data illustrate that the RhoA signaling pathway negatively modulates neurite outgrowth and elevates the expression of Glu-tubulin (a marker for a stabilized microtubule). Meanwhile, the microtubule-severing proteins spastin and p60-katanin were downregulated by the RhoA signaling pathway. When spastin and p60-katanin were knocked down, the effects of RhoA inhibition on neurite outgrowth were significantly reversed. Taken together, this study demonstrates that the RhoA pathway-mediated inhibition of neurite outgrowth is not only related to the modulation of microfilament dynamics but is also attributable to the regulation of the expression of spastin and p60-katanin and thus influences microtubule dynamics.
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139
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Yousefzadeh SA, Hesslow G, Shumyatsky GP, Meck WH. Internal Clocks, mGluR7 and Microtubules: A Primer for the Molecular Encoding of Target Durations in Cerebellar Purkinje Cells and Striatal Medium Spiny Neurons. Front Mol Neurosci 2020; 12:321. [PMID: 31998074 PMCID: PMC6965020 DOI: 10.3389/fnmol.2019.00321] [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: 08/13/2019] [Accepted: 12/16/2019] [Indexed: 12/16/2022] Open
Abstract
The majority of studies in the field of timing and time perception have generally focused on sub- and supra-second time scales, specific behavioral processes, and/or discrete neuronal circuits. In an attempt to find common elements of interval timing from a broader perspective, we review the literature and highlight the need for cell and molecular studies that can delineate the neural mechanisms underlying temporal processing. Moreover, given the recent attention to the function of microtubule proteins and their potential contributions to learning and memory consolidation/re-consolidation, we propose that these proteins play key roles in coding temporal information in cerebellar Purkinje cells (PCs) and striatal medium spiny neurons (MSNs). The presence of microtubules at relevant neuronal sites, as well as their adaptability, dynamic structure, and longevity, makes them a suitable candidate for neural plasticity at both intra- and inter-cellular levels. As a consequence, microtubules appear capable of maintaining a temporal code or engram and thereby regulate the firing patterns of PCs and MSNs known to be involved in interval timing. This proposed mechanism would control the storage of temporal information triggered by postsynaptic activation of mGluR7. This, in turn, leads to alterations in microtubule dynamics through a "read-write" memory process involving alterations in microtubule dynamics and their hexagonal lattice structures involved in the molecular basis of temporal memory.
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Affiliation(s)
- S. Aryana Yousefzadeh
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
| | - Germund Hesslow
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Gleb P. Shumyatsky
- Department of Genetics, Rutgers University, Piscataway, NJ, United States
| | - Warren H. Meck
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
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140
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Vargas EJM, Matamoros AJ, Qiu J, Jan CH, Wang Q, Gorczyca D, Han TW, Weissman JS, Jan YN, Banerjee S, Song Y. The microtubule regulator ringer functions downstream from the RNA repair/splicing pathway to promote axon regeneration. Genes Dev 2020; 34:194-208. [PMID: 31919191 PMCID: PMC7000917 DOI: 10.1101/gad.331330.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/10/2019] [Indexed: 12/17/2022]
Abstract
In this study, Vargas et al. set out to elucidate the downstream effectors of the Rtca-mediated RNA repair/splicing pathway. Using genome-wide transcriptome analysis, the authors demonstrate that the microtubule-associated protein (MAP) tubulin polymerization-promoting protein (TPPP) ringer functions downstream from and is suppressed by Rtca via Xbp1-dependent transcription. Ringer cell-autonomously promotes axon regeneration in the peripheral and central nervous system. Promoting axon regeneration in the central and peripheral nervous system is of clinical importance in neural injury and neurodegenerative diseases. Both pro- and antiregeneration factors are being identified. We previously reported that the Rtca mediated RNA repair/splicing pathway restricts axon regeneration by inhibiting the nonconventional splicing of Xbp1 mRNA under cellular stress. However, the downstream effectors remain unknown. Here, through transcriptome profiling, we show that the tubulin polymerization-promoting protein (TPPP) ringmaker/ringer is dramatically increased in Rtca-deficient Drosophila sensory neurons, which is dependent on Xbp1. Ringer is expressed in sensory neurons before and after injury, and is cell-autonomously required for axon regeneration. While loss of ringer abolishes the regeneration enhancement in Rtca mutants, its overexpression is sufficient to promote regeneration both in the peripheral and central nervous system. Ringer maintains microtubule stability/dynamics with the microtubule-associated protein futsch/MAP1B, which is also required for axon regeneration. Furthermore, ringer lies downstream from and is negatively regulated by the microtubule-associated deacetylase HDAC6, which functions as a regeneration inhibitor. Taken together, our findings suggest that ringer acts as a hub for microtubule regulators that relays cellular status information, such as cellular stress, to the integrity of microtubules in order to instruct neuroregeneration.
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Affiliation(s)
- Ernest J Monahan Vargas
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Andrew J Matamoros
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jingyun Qiu
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Calvin H Jan
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Qin Wang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - David Gorczyca
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Tina W Han
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Swati Banerjee
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Yuanquan Song
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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141
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Genualdi C, Feinstein S, Wilson L, Jordan M, Stagg N. Assessing the utility of in vitro microtubule assays for studying mechanisms of peripheral neuropathy with the microtubule inhibitor class of cancer chemotherapy. Chem Biol Interact 2020; 315:108906. [DOI: 10.1016/j.cbi.2019.108906] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/16/2019] [Accepted: 11/18/2019] [Indexed: 01/28/2023]
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142
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Chou VT, Johnson S, Long J, Vounatsos M, Van Vactor D. dTACC restricts bouton addition and regulates microtubule organization at the Drosophila neuromuscular junction. Cytoskeleton (Hoboken) 2020; 77:4-15. [PMID: 31702858 PMCID: PMC7027520 DOI: 10.1002/cm.21578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/11/2019] [Accepted: 11/05/2019] [Indexed: 12/20/2022]
Abstract
Regulation of the synaptic cytoskeleton is essential to proper neuronal development and wiring. Perturbations in neuronal microtubules (MTs) are associated with numerous pathologies, yet it remains unclear how changes in MTs may be coupled to synapse morphogenesis. Studies have identified many MT regulators that promote synapse growth. However, less is known about the factors that restrict growth, despite the potential links of synaptic overgrowth to severe neurological conditions. Here, we report that dTACC, which is implicated in MT assembly and stability, prevents synapse overgrowth at the Drosophila neuromuscular junction by restricting addition of new boutons throughout larval development. dTACC localizes to the axonal MT lattice and is required to maintain tubulin levels and the integrity of higher-order MT structures in motor axon terminals. While previous reports have demonstrated the roles of MT-stabilizing proteins in promoting synapse growth, our findings suggest that in certain contexts, MT stabilization may correlate with restricted growth.
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Affiliation(s)
- Vivian T. Chou
- Department of Cell Biology and Program in NeuroscienceBlavatnik Institute, Harvard Medical SchoolBostonMassachusetts
| | - Seth Johnson
- Department of Cell Biology and Program in NeuroscienceBlavatnik Institute, Harvard Medical SchoolBostonMassachusetts
| | - Jennifer Long
- Department of Cell Biology and Program in NeuroscienceBlavatnik Institute, Harvard Medical SchoolBostonMassachusetts
| | - Maxime Vounatsos
- Department of Cell Biology and Program in NeuroscienceBlavatnik Institute, Harvard Medical SchoolBostonMassachusetts
| | - David Van Vactor
- Department of Cell Biology and Program in NeuroscienceBlavatnik Institute, Harvard Medical SchoolBostonMassachusetts
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143
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Courson JA, Smith I, Do T, Landry PT, Hargrave A, Behzad AR, Hanlon SD, Rumbaut RE, Smith CW, Burns AR. Serial block-face scanning electron microscopy reveals neuronal-epithelial cell fusion in the mouse cornea. PLoS One 2019; 14:e0224434. [PMID: 31721785 PMCID: PMC6853292 DOI: 10.1371/journal.pone.0224434] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/14/2019] [Indexed: 11/28/2022] Open
Abstract
The cornea is the most highly innervated tissue in the body. It is generally accepted that corneal stromal nerves penetrate the epithelial basal lamina giving rise to intra-epithelial nerves. During the course of a study wherein we imaged corneal nerves in mice, we observed a novel neuronal-epithelial cell interaction whereby nerves approaching the epithelium in the cornea fused with basal epithelial cells, such that their plasma membranes were continuous and the neuronal axoplasm freely abutted the epithelial cytoplasm. In this study we sought to determine the frequency, distribution, and morphological profile of neuronal-epithelial cell fusion events within the cornea. Serial electron microscopy images were obtained from the anterior stroma in the paralimbus and central cornea of 8–10 week old C57BL/6J mice. We found evidence of a novel alternative behavior involving a neuronal-epithelial interaction whereby 42.8% of central corneal nerve bundles approaching the epithelium contain axons that fuse with basal epithelial cells. The average surface-to-volume ratio of a penetrating nerve was 3.32, while the average fusing nerve was smaller at 1.39 (p ≤ 0.0001). Despite this, both neuronal-epithelial cell interactions involve similarly sized discontinuities in the basal lamina. In order to verify the plasma membrane continuity between fused neurons and epithelial cells we used the lipophilic membrane tracer DiI. The majority of corneal nerves were labeled with DiI after application to the trigeminal ganglion and, consistent with our ultrastructural observations, fusion sites recognized as DiI-labeled basal epithelial cells were located at points of stromal nerve termination. These studies provide evidence that neuronal-epithelial cell fusion is a cell-cell interaction that occurs primarily in the central cornea, and fusing nerve bundles are morphologically distinct from penetrating nerve bundles. This is, to our knowledge, the first description of neuronal-epithelial cell fusion in the literature adding a new level of complexity to the current understanding of corneal innervation.
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Affiliation(s)
- Justin A. Courson
- University of Houston, College of Optometry, Houston, TX, United States of America
- * E-mail:
| | - Ian Smith
- University of Houston, College of Optometry, Houston, TX, United States of America
| | - Thao Do
- University of Houston, College of Optometry, Houston, TX, United States of America
| | - Paul T. Landry
- University of Houston, College of Optometry, Houston, TX, United States of America
| | - Aubrey Hargrave
- University of Houston, College of Optometry, Houston, TX, United States of America
| | - Ali R. Behzad
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Sam D. Hanlon
- University of Houston, College of Optometry, Houston, TX, United States of America
| | - Rolando E. Rumbaut
- Baylor College of Medicine, Children’s Nutrition Center, Houston, TX, United States of America
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, United States of America
| | - C. Wayne Smith
- Baylor College of Medicine, Children’s Nutrition Center, Houston, TX, United States of America
| | - Alan R. Burns
- University of Houston, College of Optometry, Houston, TX, United States of America
- Baylor College of Medicine, Children’s Nutrition Center, Houston, TX, United States of America
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144
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Hahn I, Voelzmann A, Liew YT, Costa-Gomes B, Prokop A. The model of local axon homeostasis - explaining the role and regulation of microtubule bundles in axon maintenance and pathology. Neural Dev 2019; 14:11. [PMID: 31706327 PMCID: PMC6842214 DOI: 10.1186/s13064-019-0134-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Axons are the slender, cable-like, up to meter-long projections of neurons that electrically wire our brains and bodies. In spite of their challenging morphology, they usually need to be maintained for an organism's lifetime. This makes them key lesion sites in pathological processes of ageing, injury and neurodegeneration. The morphology and physiology of axons crucially depends on the parallel bundles of microtubules (MTs), running all along to serve as their structural backbones and highways for life-sustaining cargo transport and organelle dynamics. Understanding how these bundles are formed and then maintained will provide important explanations for axon biology and pathology. Currently, much is known about MTs and the proteins that bind and regulate them, but very little about how these factors functionally integrate to regulate axon biology. As an attempt to bridge between molecular mechanisms and their cellular relevance, we explain here the model of local axon homeostasis, based on our own experiments in Drosophila and published data primarily from vertebrates/mammals as well as C. elegans. The model proposes that (1) the physical forces imposed by motor protein-driven transport and dynamics in the confined axonal space, are a life-sustaining necessity, but pose a strong bias for MT bundles to become disorganised. (2) To counterbalance this risk, MT-binding and -regulating proteins of different classes work together to maintain and protect MT bundles as necessary transport highways. Loss of balance between these two fundamental processes can explain the development of axonopathies, in particular those linking to MT-regulating proteins, motors and transport defects. With this perspective in mind, we hope that more researchers incorporate MTs into their work, thus enhancing our chances of deciphering the complex regulatory networks that underpin axon biology and pathology.
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Affiliation(s)
- Ines Hahn
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - André Voelzmann
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Yu-Ting Liew
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Beatriz Costa-Gomes
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK.
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145
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146
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Araújo SJ. Centrosomes in Branching Morphogenesis. Results Probl Cell Differ 2019; 67:323-336. [PMID: 31435801 DOI: 10.1007/978-3-030-23173-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The centrosome, a major microtubule organizer, has important functions in regulating the cytoskeleton as well as the position of cellular structures and orientation of cells within tissues. The centrosome serves as the main cytoskeleton-organizing centre in the cell and is the classical site of microtubule nucleation and anchoring. For these reasons, centrosomes play a very important role in morphogenesis, not just in the early stages of cell divisions but also in the later stages of organogenesis. Many organs such as lung, kidney and blood vessels develop from epithelial tubes that branch into complex networks. Cells in the nervous system also form highly branched structures in order to build complex neuronal networks. During branching morphogenesis, cells have to rearrange within tissues though multicellular branching or through subcellular branching, also known as single-cell branching. For highly branched structures to be formed during embryonic development, the cytoskeleton needs to be extensively remodelled. The centrosome has been shown to play an important role during these events.
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Affiliation(s)
- Sofia J Araújo
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain.
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147
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Barbier P, Zejneli O, Martinho M, Lasorsa A, Belle V, Smet-Nocca C, Tsvetkov PO, Devred F, Landrieu I. Role of Tau as a Microtubule-Associated Protein: Structural and Functional Aspects. Front Aging Neurosci 2019; 11:204. [PMID: 31447664 PMCID: PMC6692637 DOI: 10.3389/fnagi.2019.00204] [Citation(s) in RCA: 253] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/18/2019] [Indexed: 12/24/2022] Open
Abstract
Microtubules (MTs) play a fundamental role in many vital processes such as cell division and neuronal activity. They are key structural and functional elements in axons, supporting neurite differentiation and growth, as well as transporting motor proteins along the axons, which use MTs as support tracks. Tau is a stabilizing MT associated protein, whose functions are mainly regulated by phosphorylation. A disruption of the MT network, which might be caused by Tau loss of function, is observed in a group of related diseases called tauopathies, which includes Alzheimer’s disease (AD). Tau is found hyperphosphorylated in AD, which might account for its loss of MT stabilizing capacity. Since destabilization of MTs after dissociation of Tau could contribute to toxicity in neurodegenerative diseases, a molecular understanding of this interaction and its regulation is essential.
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Affiliation(s)
- Pascale Barbier
- Fac Pharm, Aix Marseille Univ., Centre National de la Recherche Scientifique (CNRS), Inst Neurophysiopathol (INP), Fac Pharm, Marseille, France
| | - Orgeta Zejneli
- Univ. Lille, Centre National de la Recherche Scientifique (CNRS), UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), Lille, France.,Univ. Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), CHU-Lille, UMR-S 1172, Centre de Recherche Jean-Pierre AUBERT (JPArc), Lille, France
| | - Marlène Martinho
- Aix Marseille Univ., Centre National de la Recherche Scientifique (CNRS), UMR 7281, Bioénergétique et Ingénierie des Protéines (BIP), Marseille, France
| | - Alessia Lasorsa
- Univ. Lille, Centre National de la Recherche Scientifique (CNRS), UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), Lille, France
| | - Valérie Belle
- Aix Marseille Univ., Centre National de la Recherche Scientifique (CNRS), UMR 7281, Bioénergétique et Ingénierie des Protéines (BIP), Marseille, France
| | - Caroline Smet-Nocca
- Univ. Lille, Centre National de la Recherche Scientifique (CNRS), UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), Lille, France
| | - Philipp O Tsvetkov
- Fac Pharm, Aix Marseille Univ., Centre National de la Recherche Scientifique (CNRS), Inst Neurophysiopathol (INP), Fac Pharm, Marseille, France
| | - François Devred
- Fac Pharm, Aix Marseille Univ., Centre National de la Recherche Scientifique (CNRS), Inst Neurophysiopathol (INP), Fac Pharm, Marseille, France
| | - Isabelle Landrieu
- Univ. Lille, Centre National de la Recherche Scientifique (CNRS), UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), Lille, France
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148
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MAP7 Prevents Axonal Branch Retraction by Creating a Stable Microtubule Boundary to Rescue Polymerization. J Neurosci 2019; 39:7118-7131. [PMID: 31391261 DOI: 10.1523/jneurosci.0775-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/16/2019] [Accepted: 07/31/2019] [Indexed: 01/07/2023] Open
Abstract
Complex neural circuits are built from axonal branches that allow each neuron to connect with multiple targets. During development, maturation of nascent branches depends on stabilization of newly assembled or transported microtubules, which are thought to be regulated by microtubule-associated proteins (MAPs). However, because many known MAPs inhibit branch formation, it is not clear which MAP is responsible for regulating microtubule stability during branch development. Here, we show that MAP7, a less-well understood MAP that is localized to branch junctions, provides a key molecular mechanism to regulate microtubule stability during branch formation. In developing rodent sensory neurons of mixed sex, MAP7 is required for branch maturation mainly by preventing branch retraction. This function is mediated by the ability of MAP7 to control microtubule stability, as microtubules are more stable at branch junctions where MAP7 is localized. Consistently, nascent branches depleted of MAP7 have decreased stable microtubules but increased dynamic microtubules. Moreover, MAP7 binds to the acetylated and stable region of individual microtubules and avoids the dynamic plus end, thereby creating a boundary that prevents microtubule depolymerization and rescues microtubule polymerization. This unique binding property, which is not observed for other MAPs, can prevent branch retraction caused by laser-induced severing or nocodazole-induced microtubule depolymerization. Together, our study identifies a novel molecular mechanism mediated by MAP7 to regulate microtubule stability and strengthen branches at different stages of axonal branch morphogenesis.SIGNIFICANCE STATEMENT Development and maintenance of axonal branches rely on microtubule stability, but the underlying molecular mechanisms are not fully understood. Here, we show that MAP7, a unique protein that interacts with both microtubules and the motor protein kinesin-1, plays a key role at branch junctions. MAP7 stabilizes microtubules in nascent branches and prevents branch retraction during branch maturation or after laser-induced injury. MAP7 also binds to the acetylated region of microtubules to prevent depolymerization and rescue polymerization. This unique binding property supports a novel mechanism mediated by MAP7 to cooperate with other MAPs and control microtubule stability during axonal branch development. This mechanism could also impact microtubule regulation in branch regeneration after nerve injury.
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149
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Chasman D, Iyer N, Fotuhi Siahpirani A, Estevez Silva M, Lippmann E, McIntosh B, Probasco MD, Jiang P, Stewart R, Thomson JA, Ashton RS, Roy S. Inferring Regulatory Programs Governing Region Specificity of Neuroepithelial Stem Cells during Early Hindbrain and Spinal Cord Development. Cell Syst 2019; 9:167-186.e12. [PMID: 31302154 DOI: 10.1016/j.cels.2019.05.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 05/05/2019] [Accepted: 05/30/2019] [Indexed: 12/19/2022]
Abstract
Neuroepithelial stem cells (NSC) from different anatomical regions of the embryonic neural tube's rostrocaudal axis can differentiate into diverse central nervous system tissues, but the transcriptional regulatory networks governing these processes are incompletely understood. Here, we measure region-specific NSC gene expression along the rostrocaudal axis in a human pluripotent stem cell model of early central nervous system development over a 72-h time course, spanning the hindbrain to cervical spinal cord. We introduce Escarole, a probabilistic clustering algorithm for non-stationary time series, and combine it with prior-based regulatory network inference to identify genes that are regulated dynamically and predict their upstream regulators. We identify known regulators of patterning and neural development, including the HOX genes, and predict a direct regulatory connection between the transcription factor POU3F2 and target gene STMN2. We demonstrate that POU3F2 is required for expression of STMN2, suggesting that this regulatory connection is important for region specificity of NSCs.
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Affiliation(s)
- Deborah Chasman
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Nisha Iyer
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alireza Fotuhi Siahpirani
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Computer Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Maria Estevez Silva
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ethan Lippmann
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian McIntosh
- Regenerative Biology Theme, Morgridge Institute for Research, Madison, WI 53715, USA
| | - Mitchell D Probasco
- Regenerative Biology Theme, Morgridge Institute for Research, Madison, WI 53715, USA
| | - Peng Jiang
- Regenerative Biology Theme, Morgridge Institute for Research, Madison, WI 53715, USA
| | - Ron Stewart
- Regenerative Biology Theme, Morgridge Institute for Research, Madison, WI 53715, USA
| | - James A Thomson
- Regenerative Biology Theme, Morgridge Institute for Research, Madison, WI 53715, USA
| | - Randolph S Ashton
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Sushmita Roy
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53792, USA.
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150
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Savchenko V, Kalinin S, Boullerne AI, Kowal K, Lin SX, Feinstein DL. Effects of the CRMP2 activator lanthionine ketimine ethyl ester on oligodendrocyte progenitor cells. J Neuroimmunol 2019; 334:576977. [PMID: 31177034 DOI: 10.1016/j.jneuroim.2019.576977] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/15/2019] [Accepted: 05/30/2019] [Indexed: 01/24/2023]
Abstract
We previously showed LKE (lanthionine ketimine ester) reduces disease in the EAE model of multiple sclerosis, however whether LKE affects oligodendrocytes (OLGs) was not tested. In OLG progenitor cells (OPCs), LKE increased process number and area, but not PDGF-receptor-alpha expressing cells. In contrast, PDGF increased OPC numbers, but reduced process number and area. LKE increased collapsin response mediator protein-2 (CRMP2) expression, an LKE target, and CRMP2-expressing OLGs expressed myelin basic protein. LKE increased markers of OPC maturation, while PDGF, but not LKE, increased Sox2 expression. Our findings suggest that effects on OPCs may contribute to LKE beneficial actions in EAE.
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Affiliation(s)
| | - Sergey Kalinin
- University of Illinois, Chicago, IL 60612, United States of America
| | - Anne I Boullerne
- University of Illinois, Chicago, IL 60612, United States of America
| | - Kathy Kowal
- University of Illinois, Chicago, IL 60612, United States of America
| | - Shao Xia Lin
- University of Illinois, Chicago, IL 60612, United States of America
| | - Douglas L Feinstein
- University of Illinois, Chicago, IL 60612, United States of America; Jesse Brown VA Medical Center, Chicago, IL 60612, United States of America.
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