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Nieuwenhuis B, Haenzi B, Hilton S, Carnicer-Lombarte A, Hobo B, Verhaagen J, Fawcett JW. Optimization of adeno-associated viral vector-mediated transduction of the corticospinal tract: comparison of four promoters. Gene Ther 2020; 28:56-74. [PMID: 32576975 PMCID: PMC7902269 DOI: 10.1038/s41434-020-0169-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/01/2020] [Accepted: 06/11/2020] [Indexed: 12/22/2022]
Abstract
Adeno-associated viral vectors are widely used as vehicles for gene transfer to the nervous system. The promoter and viral vector serotype are two key factors that determine the expression dynamics of the transgene. A previous comparative study has demonstrated that AAV1 displays efficient transduction of layer V corticospinal neurons, but the optimal promoter for transgene expression in corticospinal neurons has not been determined yet. In this paper, we report a side-by-side comparison between four commonly used promoters: the short CMV early enhancer/chicken β actin (sCAG), human cytomegalovirus (hCMV), mouse phosphoglycerate kinase (mPGK) and human synapsin (hSYN) promoter. Reporter constructs with each of these promoters were packaged in AAV1, and were injected in the sensorimotor cortex of rats and mice in order to transduce the corticospinal tract. Transgene expression levels and the cellular transduction profile were examined after 6 weeks. The AAV1 vectors harbouring the hCMV and sCAG promoters resulted in transgene expression in neurons, astrocytes and oligodendrocytes. The mPGK and hSYN promoters directed the strongest transgene expression. The mPGK promoter did drive expression in cortical neurons and oligodendrocytes, while transduction with AAV harbouring the hSYN promoter resulted in neuron-specific expression, including perineuronal net expressing interneurons and layer V corticospinal neurons. This promoter comparison study contributes to improve transgene delivery into the brain and spinal cord. The optimized transduction of the corticospinal tract will be beneficial for spinal cord injury research.
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Affiliation(s)
- Bart Nieuwenhuis
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK. .,Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands.
| | - Barbara Haenzi
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Sam Hilton
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Alejandro Carnicer-Lombarte
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Barbara Hobo
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands
| | - Joost Verhaagen
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands.,Centre for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - James W Fawcett
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.,Centre of Reconstructive Neuroscience, Institute of Experimental Medicine, Vídeňská 1083, 142 20, Prague 4, Czech Republic
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53
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Hecker A, Anger P, Braaker PN, Schulze W, Schuster S. High-resolution mapping of injury-site dependent functional recovery in a single axon in zebrafish. Commun Biol 2020; 3:307. [PMID: 32533058 PMCID: PMC7293241 DOI: 10.1038/s42003-020-1034-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 05/26/2020] [Indexed: 01/09/2023] Open
Abstract
In non-mammalian vertebrates, some neurons can regenerate after spinal cord injury. One of these, the giant Mauthner (M-) neuron shows a uniquely direct link to a robust survival-critical escape behavior but appears to regenerate poorly. Here we use two-photon microscopy in parallel with behavioral assays in zebrafish to show that the M-axon can regenerate very rapidly and that the recovery of functionality lags by just days. However, we also find that the site of the injury is critical: While regeneration is poor both close and far from the soma, rapid regeneration and recovery of function occurs for injuries between 10% and 50% of total axon length. Our findings show that rapid regeneration and the recovery of function can be studied at remarkable temporal resolution after targeted injury of one single M-axon and that the decision between poor and rapid regeneration can be studied in this one axon. Alexander Hecker et al. study the regeneration potential of the axon of the giant Mauthner (M) neuron in zebrafish. Using two-photon microscopy and behavioral assays, they show that the M-axon can recover rapidly days after injury. They also characterize the optimal injury site that enables rapid regeneration and functional recovery.
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Affiliation(s)
- Alexander Hecker
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany.
| | - Pamela Anger
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Philipp N Braaker
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Wolfram Schulze
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Stefan Schuster
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany.
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54
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Kumamaru H, Lu P, Rosenzweig ES, Kadoya K, Tuszynski MH. Regenerating Corticospinal Axons Innervate Phenotypically Appropriate Neurons within Neural Stem Cell Grafts. Cell Rep 2020; 26:2329-2339.e4. [PMID: 30811984 PMCID: PMC6487864 DOI: 10.1016/j.celrep.2019.01.099] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/01/2018] [Accepted: 01/28/2019] [Indexed: 01/13/2023] Open
Abstract
Neural progenitor cell grafts form new relays across sites of spinal cord injury (SCI). Using a panel of neuronal markers, we demonstrate that spinal neural progenitor grafts to sites of rodent SCI adopt diverse spinal motor and sensory interneuronal fates, representing most neuronal subtypes of the intact spinal cord, and spontaneously segregate into domains of distinct cell clusters. Host corticospinal motor axons regenerating into neural progenitor grafts innervate appropriate pre-motor interneurons, based on trans-synaptic tracing with herpes simplex virus. A human spinal neural progenitor cell graft to a non-human primate also received topographically appropriate corticospinal axon regeneration. Thus, grafted spinal neural progenitor cells give rise to a variety of neuronal progeny that are typical of the normal spinal cord; remarkably, regenerating injured adult corticospinal motor axons spontaneously locate appropriate motor domains in the heterogeneous, developing graft environment, without a need for additional exogenous guidance. Kumamaru et al. demonstrate that spinal cord neural progenitor cell grafts spontaneously segregate into motor and sensory domains when implanted into sites of spinal cord injury in rats and primates. Host corticospinal axons regenerating into grafts preferentially regenerate and synapse onto motor interneuron-rich domains, avoiding inappropriate sensory domains.
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Affiliation(s)
- Hiromi Kumamaru
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Department of Orthopaedic Surgery, Kyushu University Beppu Hospital, Oita, Japan
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Veterans Administration San Diego Healthcare System, San Diego, CA, USA
| | - Ephron S Rosenzweig
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Ken Kadoya
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Department of Orthopaedic Surgery, Hokkaido University, Sapporo, Japan
| | - Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Veterans Administration San Diego Healthcare System, San Diego, CA, USA.
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55
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Regenerative Potential of Carbon Monoxide in Adult Neural Circuits of the Central Nervous System. Int J Mol Sci 2020; 21:ijms21072273. [PMID: 32218342 PMCID: PMC7177523 DOI: 10.3390/ijms21072273] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/17/2020] [Accepted: 03/23/2020] [Indexed: 01/04/2023] Open
Abstract
Regeneration of adult neural circuits after an injury is limited in the central nervous system (CNS). Heme oxygenase (HO) is an enzyme that produces HO metabolites, such as carbon monoxide (CO), biliverdin and iron by heme degradation. CO may act as a biological signal transduction effector in CNS regeneration by stimulating neuronal intrinsic and extrinsic mechanisms as well as mitochondrial biogenesis. CO may give directions by which the injured neurovascular system switches into regeneration mode by stimulating endogenous neural stem cells and endothelial cells to produce neurons and vessels capable of replacing injured neurons and vessels in the CNS. The present review discusses the regenerative potential of CO in acute and chronic neuroinflammatory diseases of the CNS, such as stroke, traumatic brain injury, multiple sclerosis and Alzheimer’s disease and the role of signaling pathways and neurotrophic factors. CO-mediated facilitation of cellular communications may boost regeneration, consequently forming functional adult neural circuits in CNS injury.
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56
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Han Q, Xie Y, Ordaz JD, Huh AJ, Huang N, Wu W, Liu N, Chamberlain KA, Sheng ZH, Xu XM. Restoring Cellular Energetics Promotes Axonal Regeneration and Functional Recovery after Spinal Cord Injury. Cell Metab 2020; 31:623-641.e8. [PMID: 32130884 PMCID: PMC7188478 DOI: 10.1016/j.cmet.2020.02.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 11/24/2019] [Accepted: 01/31/2020] [Indexed: 01/30/2023]
Abstract
Axonal regeneration in the central nervous system (CNS) is a highly energy-demanding process. Extrinsic insults and intrinsic restrictions lead to an energy crisis in injured axons, raising the question of whether recovering energy deficits facilitates regeneration. Here, we reveal that enhancing axonal mitochondrial transport by deleting syntaphilin (Snph) recovers injury-induced mitochondrial depolarization. Using three CNS injury mouse models, we demonstrate that Snph-/- mice display enhanced corticospinal tract (CST) regeneration passing through a spinal cord lesion, accelerated regrowth of monoaminergic axons across a transection gap, and increased compensatory sprouting of uninjured CST. Notably, regenerated CST axons form functional synapses and promote motor functional recovery. Administration of the bioenergetic compound creatine boosts CST regenerative capacity in Snph-/- mice. Our study provides mechanistic insights into intrinsic regeneration failure in CNS and suggests that enhancing mitochondrial transport and cellular energetics are promising strategies to promote regeneration and functional restoration after CNS injuries.
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Affiliation(s)
- Qi Han
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yuxiang Xie
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Josue D Ordaz
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Andrew J Huh
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ning Huang
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wei Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Naikui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kelly A Chamberlain
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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57
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Griffin JM, Bradke F. Therapeutic repair for spinal cord injury: combinatory approaches to address a multifaceted problem. EMBO Mol Med 2020; 12:e11505. [PMID: 32090481 PMCID: PMC7059014 DOI: 10.15252/emmm.201911505] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/07/2020] [Accepted: 01/31/2020] [Indexed: 12/21/2022] Open
Abstract
The recent years saw the advent of promising preclinical strategies that combat the devastating effects of a spinal cord injury (SCI) that are progressing towards clinical trials. However, individually, these treatments produce only modest levels of recovery in animal models of SCI that could hamper their implementation into therapeutic strategies in spinal cord injured humans. Combinational strategies have demonstrated greater beneficial outcomes than their individual components alone by addressing multiple aspects of SCI pathology. Clinical trial designs in the future will eventually also need to align with this notion. The scenario will become increasingly complex as this happens and conversations between basic researchers and clinicians are required to ensure accurate study designs and functional readouts.
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Affiliation(s)
- Jarred M Griffin
- Laboratory for Axonal Growth and Regeneration, German Centre for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Frank Bradke
- Laboratory for Axonal Growth and Regeneration, German Centre for Neurodegenerative Diseases (DZNE), Bonn, Germany
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58
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Lai M, Pan M, Ge L, Liu J, Deng J, Wang X, Li L, Wen J, Tan D, Zhang H, Hu X, Fu L, Xu Y, Li Z, Qiu X, Chen G, Guo J. NeuroD1 overexpression in spinal neurons accelerates axonal regeneration after sciatic nerve injury. Exp Neurol 2020; 327:113215. [PMID: 31991126 DOI: 10.1016/j.expneurol.2020.113215] [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: 07/20/2019] [Revised: 11/13/2019] [Accepted: 01/25/2020] [Indexed: 12/26/2022]
Abstract
Neurogenic differentiation 1 (NeuroD1) is mainlyexpressed in developing neurons where it plays critical roles in neuronal maturation and neurite elongation. The potential role and mechanism of NeuroD1 in adult axonal regeneration is not clear. The present study used synapsin (SYN) Cre and AAV9-Flex vectors to conditionally overexpress NeuroD1 in adult spinal neurons and found that NeuroD1 overexpression significantly accelerated axonal regeneration and functional recovery after sciatic nerve injury. Further in vitro and in vivo experiments suggested that the mechanism of NeuroD1 promotion on axonal regeneration was related to its regulation of the expression of neurotrophin BDNF and its receptor TrkB as well as a microtubule severing protein spastin.
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Affiliation(s)
- Muhua Lai
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Mengjie Pan
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, United States
| | - Longjiao Ge
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jingmin Liu
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Junyao Deng
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Xianghai Wang
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Lixia Li
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Jinkun Wen
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Dandan Tan
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Haowen Zhang
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Xiaofang Hu
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Lanya Fu
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Yizhou Xu
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Zhenlin Li
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China
| | - Xiaozhong Qiu
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China
| | - Gong Chen
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, China; Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, United States
| | - Jiasong Guo
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, Guangzhou, China; Department of Histology and Embryology, Southern Medical University, Guangzhou, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Guangzhou, China.
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59
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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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60
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Abstract
Neurons develop polarity by the formation of specialized dendritic and axonal structural compartments. A new report now provides evidence that reveals how neurons regulate the initiation and further maintenance of axonal growth, challenging our currently held view of RhoA function in axogenesis.
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Affiliation(s)
- Anton Omelchenko
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854, USA.
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61
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Dupraz S, Hilton BJ, Husch A, Santos TE, Coles CH, Stern S, Brakebusch C, Bradke F. RhoA Controls Axon Extension Independent of Specification in the Developing Brain. Curr Biol 2019; 29:3874-3886.e9. [PMID: 31679934 DOI: 10.1016/j.cub.2019.09.040] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 08/22/2019] [Accepted: 09/16/2019] [Indexed: 12/22/2022]
Abstract
The specification of an axon and its subsequent outgrowth are key steps during neuronal polarization, a prerequisite to wire the brain. The Rho-guanosine triphosphatase (GTPase) RhoA is believed to be a central player in these processes. However, its physiological role has remained undefined. Here, genetic loss- and gain-of-function experiments combined with time-lapse microscopy, cell culture, and in vivo analysis show that RhoA is not involved in axon specification but confines the initiation of neuronal polarization and axon outgrowth during development. Biochemical analysis and super-resolution microscopy together with molecular and pharmacological manipulations reveal that RhoA restrains axon growth by activating myosin-II-mediated actin arc formation in the growth cone to prevent microtubules from protruding toward the leading edge. Through this mechanism, RhoA regulates the duration of axon growth and pause phases, thus controlling the tightly timed extension of developing axons. Thereby, this work unravels physiologically relevant players coordinating actin-microtubule interactions during axon growth.
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Affiliation(s)
- Sebastian Dupraz
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
| | - Brett J Hilton
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
| | - Andreas Husch
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
| | - Telma E Santos
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
| | - Charlotte H Coles
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
| | - Sina Stern
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
| | - Cord Brakebusch
- Biotech Research & Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Frank Bradke
- Axonal Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany.
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62
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Bradbury EJ, Burnside ER. Moving beyond the glial scar for spinal cord repair. Nat Commun 2019; 10:3879. [PMID: 31462640 PMCID: PMC6713740 DOI: 10.1038/s41467-019-11707-7] [Citation(s) in RCA: 388] [Impact Index Per Article: 77.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 07/25/2019] [Indexed: 02/08/2023] Open
Abstract
Traumatic spinal cord injury results in severe and irreversible loss of function. The injury triggers a complex cascade of inflammatory and pathological processes, culminating in formation of a scar. While traditionally referred to as a glial scar, the spinal injury scar in fact comprises multiple cellular and extracellular components. This multidimensional nature should be considered when aiming to understand the role of scarring in limiting tissue repair and recovery. In this Review we discuss recent advances in understanding the composition and phenotypic characteristics of the spinal injury scar, the oversimplification of defining the scar in binary terms as good or bad, and the development of therapeutic approaches to target scar components to enable improved functional outcome after spinal cord injury.
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Affiliation(s)
- Elizabeth J Bradbury
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK.
| | - Emily R Burnside
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
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63
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Tedeschi A, Dupraz S, Curcio M, Laskowski CJ, Schaffran B, Flynn KC, Santos TE, Stern S, Hilton BJ, Larson MJE, Gurniak CB, Witke W, Bradke F. ADF/Cofilin-Mediated Actin Turnover Promotes Axon Regeneration in the Adult CNS. Neuron 2019; 103:1073-1085.e6. [PMID: 31400829 DOI: 10.1016/j.neuron.2019.07.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/06/2019] [Accepted: 07/08/2019] [Indexed: 11/27/2022]
Abstract
Injured axons fail to regenerate in the adult CNS, which contrasts with their vigorous growth during embryonic development. We explored the potential of re-initiating axon extension after injury by reactivating the molecular mechanisms that drive morphogenetic transformation of neurons during development. Genetic loss- and gain-of-function experiments followed by time-lapse microscopy, in vivo imaging, and whole-mount analysis show that axon regeneration is fueled by elevated actin turnover. Actin depolymerizing factor (ADF)/cofilin controls actin turnover to sustain axon regeneration after spinal cord injury through its actin-severing activity. This pinpoints ADF/cofilin as a key regulator of axon growth competence, irrespective of developmental stage. These findings reveal the central role of actin dynamics regulation in this process and elucidate a core mechanism underlying axon growth after CNS trauma. Thereby, neurons maintain the capacity to stimulate developmental programs during adult life, expanding their potential for plasticity. Thus, actin turnover is a key process for future regenerative interventions.
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Affiliation(s)
- Andrea Tedeschi
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Sebastian Dupraz
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Michele Curcio
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Claudia J Laskowski
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Barbara Schaffran
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Kevin C Flynn
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Telma E Santos
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Sina Stern
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Brett J Hilton
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Molly J E Larson
- Center for Brain and Spinal Cord Repair, Department of Neuroscience, Wexner Medical Center, The Ohio State University, 460 W. 12th Ave., Columbus, OH 43210, USA
| | - Christine B Gurniak
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany
| | - Walter Witke
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany
| | - Frank Bradke
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany.
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64
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Teotia P, Van Hook MJ, Fischer D, Ahmad I. Human retinal ganglion cell axon regeneration by recapitulating developmental mechanisms: effects of recruitment of the mTOR pathway. Development 2019; 146:dev178012. [PMID: 31273087 PMCID: PMC6633601 DOI: 10.1242/dev.178012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/15/2019] [Indexed: 12/15/2022]
Abstract
The poor axon regeneration in the central nervous system (CNS) often leads to permanent functional deficit following disease or injury. For example, degeneration of retinal ganglion cell (RGC) axons in glaucoma leads to irreversible loss of vision. Here, we have tested the hypothesis that the mTOR pathway regulates the development of human RGCs and that its recruitment after injury facilitates axon regeneration. We observed that the mTOR pathway is active during RGC differentiation, and using the induced pluripotent stem cell model of neurogenesis show that it facilitates the differentiation, function and neuritogenesis of human RGCs. Using a microfluidic model, we demonstrate that recruitment of the mTOR pathway facilitates human RGC axon regeneration after axotomy, providing evidence that the recapitulation of developmental mechanism(s) might be a viable approach for facilitating axon regeneration in the diseased or injured human CNS, thus helping to reduce and/or recover loss of function.
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Affiliation(s)
- Pooja Teotia
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Matthew J Van Hook
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Dietmar Fischer
- Department of Cell Physiology, Ruhr University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- Division of Experimental Neurology, Medical Faculty, Heinrich Heine University, Merowingerplatz 1a, 40225 Düsseldorf, Germany
| | - Iqbal Ahmad
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE 68198, USA
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65
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Joshi M, Krishnakumar A. Hypoglycemia causes dysregulation of Neuregulin 1, ErbB receptors, Ki67 in cerebellum and brainstem during diabetes: Implications in motor function. Behav Brain Res 2019; 372:112029. [PMID: 31195035 DOI: 10.1016/j.bbr.2019.112029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/08/2019] [Accepted: 06/08/2019] [Indexed: 12/09/2022]
Abstract
Hypoglycemia induced brain injury poses a major setback to optimal blood glucose regulation during diabetes. It causes irreversible injury in several brain regions culminating in improper function. Neuregulin 1 and ErbB receptors are involved in regeneration during adulthood as well as in glucose homeostasis. We intended to understand the influence of extreme discrepancies in glycemic levels on Neuregulin 1, ErbB receptor subtypes and Ki67 expression in relation to motor deficits as a consequence of cellular dysfunction/degeneration in the cerebellum and brainstem during diabetes. Elevated oxidative stress and compromised antioxidant system havocs cerebellum and brainstem related function. Cellular alteration of Purkinje neurons in the cerebellum and presence of axonal spheroids in the brainstem are suggestive of impairment to neural circuits involved in motor function. Down regulation of Neuregulin 1, ErbB 2, ErbB 3, ErbB 4 and Ki67 expression observed during diabetes and hypoglycemia may critically cause regenerative deficiency in cerebellum. The coincident up regulation of Neuregulin 1, ErbB 2, ErbB 3 and ErbB 4 in brainstem during diabetes is an attempt to maintain regenerative homeostasis to ensure its function. However, hypoglycemic insults results in down regulation of Neuregulin 1, ErbB 4 expression that severely compromises their role in brainstem. Grid walking test confirmed motor impairment during diabetes that showed further deterioration due to hypoglycemic stress. Thus altered expression of Neuregulin 1, ErbB receptor subtypes and Ki67 during diabetes and hypoglycemia contributes to reduced cellular proliferation and deficits in motor function.
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Affiliation(s)
- Madhavi Joshi
- Institute of Science, Nirma University, Sarkhej- Gandhinagar Highway Ahmedabad 382481, Gujarat, India.
| | - Amee Krishnakumar
- Institute of Science, Nirma University, Sarkhej- Gandhinagar Highway Ahmedabad 382481, Gujarat, India.
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66
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Bremer J, Marsden KC, Miller A, Granato M. The ubiquitin ligase PHR promotes directional regrowth of spinal zebrafish axons. Commun Biol 2019; 2:195. [PMID: 31149640 PMCID: PMC6531543 DOI: 10.1038/s42003-019-0434-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/16/2019] [Indexed: 01/05/2023] Open
Abstract
To reconnect with their synaptic targets, severed axons need to regrow robustly and directionally along the pre-lesional trajectory. While mechanisms directing axonal regrowth are poorly understood, several proteins direct developmental axon outgrowth, including the ubiquitin ligase PHR (Mycbp2). Invertebrate PHR also limits regrowth of injured axons, whereas its role in vertebrate axonal regrowth remains elusive. Here we took advantage of the high regrowth capacity of spinal zebrafish axons and observed robust and directional regrowth following laser transection of spinal Mauthner axons. We found that PHR directs regrowing axons along the pre-lesional trajectory and across the transection site. At the transection site, initial regrowth of wild-type axons was multidirectional. Over time, misdirected sprouts were corrected in a PHR-dependent manner. Ablation of cyfip2, known to promote F-actin-polymerization and pharmacological inhibition of JNK reduced misdirected regrowth of PHR-deficient axons, suggesting that PHR controls directional Mauthner axonal regrowth through cyfip2- and JNK-dependent pathways.
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Affiliation(s)
- Juliane Bremer
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA USA
| | - Kurt C. Marsden
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA USA
- Present Address: Department of Biological Sciences, North Carolina State University, Raleigh, 27607 NC USA
| | - Adam Miller
- Institute of Neuroscience, University of Oregon, Eugene, 97405 OR USA
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA USA
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67
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Hilton BJ, Blanquie O, Tedeschi A, Bradke F. High-resolution 3D imaging and analysis of axon regeneration in unsectioned spinal cord with or without tissue clearing. Nat Protoc 2019; 14:1235-1260. [DOI: 10.1038/s41596-019-0140-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
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68
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Abstract
Traumatic brain and spinal cord injuries cause permanent disability. Although progress has been made in understanding the cellular and molecular mechanisms underlying the pathophysiological changes that affect both structure and function after injury to the brain or spinal cord, there are currently no cures for either condition. This may change with the development and application of multi-layer omics, new sophisticated bioinformatics tools, and cutting-edge imaging techniques. Already, these technical advances, when combined, are revealing an unprecedented number of novel cellular and molecular targets that could be manipulated alone or in combination to repair the injured central nervous system with precision. In this review, we highlight recent advances in applying these new technologies to the study of axon regeneration and rebuilding of injured neural circuitry. We then discuss the challenges ahead to translate results produced by these technologies into clinical application to help improve the lives of individuals who have a brain or spinal cord injury.
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Affiliation(s)
- Andrea Tedeschi
- Department of Neuroscience and Discovery Themes Initiative, College of Medicine, Ohio State University, Columbus, Ohio, 43210, USA
| | - Phillip G Popovich
- Center for Brain and Spinal Cord Repair, Institute for Behavioral Medicine Research, Ohio State University, Columbus, Ohio, 43210, USA
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69
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Wang Q, Cai H, Hu Z, Wu Y, Guo X, Li J, Wang H, Liu Y, Liu Y, Xie L, Xu K, Xu H, He H, Zhang H, Xiao J. Loureirin B Promotes Axon Regeneration by Inhibiting Endoplasmic Reticulum Stress: Induced Mitochondrial Dysfunction and Regulating the Akt/GSK-3β Pathway after Spinal Cord Injury. J Neurotrauma 2019; 36:1949-1964. [PMID: 30543130 DOI: 10.1089/neu.2018.5966] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Axon retraction greatly limits functional recovery after spinal cord injury (SCI) and neuron polarization, which affects processes including axon formation and development, is a promising target for promoting axon regeneration. Increasing microtubule stability has been demonstrated to improve intrinsic axon regeneration processes and is critically related to endoplasmic reticulum (ER)-mitochondria interactions. We used real-time polymerase chain reaction, Western blotting, and immunofluorescence to screen a variety of natural compounds, and found that Loureirin B (LrB) effectively promoted neuron polarization and axon regeneration in vitro and in vivo. LrB significantly inhibited ER stress and thereby promoted mitochondrial functions by regulating mitochondrial fusion. Further, LrB reactivated the Akt/GSK-3β pathway, which plays critical roles in cell survival and microtubule stabilization. Taken together, our results suggest that the effects of LrB on neuron regeneration involve the inhibition of ER stress-induced mitochondrial dysfunction and activation of the Akt/GSK-3β pathway, which further promotes microtubule stabilization. LrB may therefore be a promising candidate for facilitating recovery following SCI.
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Affiliation(s)
- Qingqing Wang
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China.,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Hanxiao Cai
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China.,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Zhenxin Hu
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China.,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Yanqing Wu
- 3 The Institute of Life Sciences, Wenzhou University, Wenzhou, China
| | - Xin Guo
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Jiawei Li
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Haoli Wang
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Yani Liu
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Yanlong Liu
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Ling Xie
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Ke Xu
- 3 The Institute of Life Sciences, Wenzhou University, Wenzhou, China
| | - Huazi Xu
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Huacheng He
- 4 College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Hongyu Zhang
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Jian Xiao
- 1 Department of Orthopedics, Second Affiliated Hospital and Yuying Children's Hospital, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China.,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
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70
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Schaffran B, Hilton BJ, Bradke F. Imaging in vivo dynamics of sensory axon responses to CNS injury. Exp Neurol 2019; 317:110-118. [PMID: 30794766 DOI: 10.1016/j.expneurol.2019.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/13/2019] [Accepted: 02/17/2019] [Indexed: 01/25/2023]
Abstract
Axons in the adult mammalian brain and spinal cord fail to regenerate upon lesion. In vivo imaging serves as a tool to investigate the immediate response of axons to injury and how the same injured axons behave over time. Here, we describe the dynamic changes that injured sensory axons undergo and methods of imaging them in vivo. First, we explain how sensory axons in the dorsal column of the adult mouse spinal cord respond to axotomy. Then, we highlight practical considerations for implementing two-photon based in vivo imaging of these axons. Finally, we describe future directions for this technique, including the possibility of in vivo imaging of subcellular dynamics within the axon.
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Affiliation(s)
| | - Brett J Hilton
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Frank Bradke
- German Center for Neurodegenerative Diseases, Bonn, Germany.
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71
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Li X, Liu D, Xiao Z, Zhao Y, Han S, Chen B, Dai J. Scaffold-facilitated locomotor improvement post complete spinal cord injury: Motor axon regeneration versus endogenous neuronal relay formation. Biomaterials 2019; 197:20-31. [PMID: 30639547 DOI: 10.1016/j.biomaterials.2019.01.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/10/2018] [Accepted: 01/05/2019] [Indexed: 01/18/2023]
Abstract
Complete transected spinal cord injury (SCI) severely influences the quality of life and mortality rates of animals and patients. In the past decade, many simple and combinatorial therapeutic treatments have been tested in improving locomotor function in animals with this extraordinarily challenging SCI. The potential mechanism for promotion of locomotor function relies either on direct motor axon regeneration through the lesion gap or indirect neuronal relay bridging to functionally reconnect transected spinal stumps. In this review, we first compare the advantages and problems of complete transection SCI animal models with other prevailing SCI models used in motor axon regeneration research. Next, we enumerate some of the popular bio-scaffolds utilized in complete SCI repair in the last decade. Then, the current state of motor axon regeneration as well as its role on locomotor improvement of animals after complete SCI is discussed. Last, the current approach of directing endogenous neuronal relays formation to achieve motor function recovery by well-designed functional bio-scaffolds implantation in complete transected SCI animals is reviewed. Although facilitating neuronal relays formation by bio-scaffolds implantation appears to be more practical and feasible than directing motor axon regeneration in promoting locomotor outcome in animals after complete SCI, there are still challenges in neuronal relays formation, maintaining and debugging for spinal cord regenerative repair.
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Affiliation(s)
- Xing Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University (CSU), Changsha, Hunan, 410008, China
| | - Dingyang Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, Hunan Province, China
| | - Zhifeng Xiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yannan Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Sufang Han
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bing Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianwu Dai
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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72
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Schaffran B, Bradke F. Reproducibility - The key towards clinical implementation of spinal cord injury treatments? Exp Neurol 2018; 313:135-136. [PMID: 30605623 DOI: 10.1016/j.expneurol.2018.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 12/28/2018] [Indexed: 10/27/2022]
Affiliation(s)
- Barbara Schaffran
- Axon Growth and Regeneration, German Center for Neurodegenerative Diseases, Bonn, Germany.
| | - Frank Bradke
- Axon Growth and Regeneration, German Center for Neurodegenerative Diseases, Bonn, Germany.
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73
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Zigmond RE, Echevarria FD. Macrophage biology in the peripheral nervous system after injury. Prog Neurobiol 2018; 173:102-121. [PMID: 30579784 DOI: 10.1016/j.pneurobio.2018.12.001] [Citation(s) in RCA: 203] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/19/2018] [Accepted: 12/17/2018] [Indexed: 12/23/2022]
Abstract
Neuroinflammation has positive and negative effects. This review focuses on the roles of macrophage in the PNS. Transection of PNS axons leads to degeneration and clearance of the distal nerve and to changes in the region of the axotomized cell bodies. In both locations, resident and infiltrating macrophages are found. Macrophages enter these areas in response to expression of the chemokine CCL2 acting on the macrophage receptor CCR2. In the distal nerve, macrophages and other phagocytes are involved in clearance of axonal debris, which removes molecules that inhibit nerve regeneration. In the cell body region, macrophage trigger the conditioning lesion response, a process in which neurons increase their regeneration after a prior lesion. In mice in which the genes for CCL2 or CCR2 are deleted, neither macrophage infiltration nor the conditioning lesion response occurs in dorsal root ganglia (DRG). Macrophages exist in different phenotypes depending on their environment. These phenotypes have different effects on axonal clearance and neurite outgrowth. The mechanism by which macrophages affect neuronal cell bodies is still under study. Overexpression of CCL2 in DRG in uninjured animals leads to macrophage accumulation in the ganglia and to an increase in the growth potential of DRG neurons. This increased growth requires activation of neuronal STAT3. In contrast, in acute demyelinating neuropathies, macrophages are involved in stripping myelin from peripheral axons. The molecular mechanisms that trigger macrophage action after trauma and in autoimmune disease are receiving increased attention and should lead to avenues to promote regeneration and protect axonal integrity.
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Affiliation(s)
- Richard E Zigmond
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, 44106-4975, USA.
| | - Franklin D Echevarria
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, 44106-4975, USA
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74
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Swindell WR, Bojanowski K, Kindy MS, Chau RMW, Ko D. GM604 regulates developmental neurogenesis pathways and the expression of genes associated with amyotrophic lateral sclerosis. Transl Neurodegener 2018; 7:30. [PMID: 30524706 PMCID: PMC6276193 DOI: 10.1186/s40035-018-0135-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/21/2018] [Indexed: 12/11/2022] Open
Abstract
Background Amyotrophic lateral sclerosis (ALS) is currently an incurable disease without highly effective pharmacological treatments. The peptide drug GM604 (GM6 or Alirinetide) was developed as a candidate ALS therapy, which has demonstrated safety and good drug-like properties with a favorable pharmacokinetic profile. GM6 is hypothesized to bolster neuron survival through the multi-target regulation of developmental pathways, but mechanisms of action are not fully understood. Methods This study used RNA-seq to evaluate transcriptome responses in SH-SY5Y neuroblastoma cells following GM6 treatment (6, 24 and 48 h). Results We identified 2867 protein-coding genes with expression significantly altered by GM6 (FDR < 0.10). Early (6 h) responses included up-regulation of Notch and hedgehog signaling components, with increased expression of developmental genes mediating neurogenesis and axon growth. Prolonged GM6 treatment (24 and 48 h) altered the expression of genes contributing to cell adhesion and the extracellular matrix. GM6 further down-regulated the expression of genes associated with mitochondria, inflammatory responses, mRNA processing and chromatin organization. GM6-increased genes were located near GC-rich motifs interacting with C2H2 zinc finger transcription factors, whereas GM6-decreased genes were located near AT-rich motifs associated with helix-turn-helix homeodomain factors. Such motifs interacted with a diverse network of transcription factors encoded by GM6-regulated genes (STAT3, HOXD11, HES7, GLI1). We identified 77 ALS-associated genes with expression significantly altered by GM6 treatment (FDR < 0.10), which were known to function in neurogenesis, axon guidance and the intrinsic apoptosis pathway. Conclusions Our findings support the hypothesis that GM6 acts through developmental-stage pathways to influence neuron survival. Gene expression responses were consistent with neurotrophic effects, ECM modulation, and activation of the Notch and hedgehog neurodevelopmental pathways. This multifaceted mechanism of action is unique among existing ALS drug candidates and may be applicable to multiple neurodegenerative diseases. Electronic supplementary material The online version of this article (10.1186/s40035-018-0135-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- William R Swindell
- 1Heritage College of Osteopathic Medicine, Ohio University, Athens, OH USA
| | | | - Mark S Kindy
- 3Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL USA.,4James A. Haley VAMC, Tampa, FL USA
| | | | - Dorothy Ko
- Genervon Biopharmaceuticals LLC, Pasadena, CA USA
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75
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Miller KE, Suter DM. An Integrated Cytoskeletal Model of Neurite Outgrowth. Front Cell Neurosci 2018; 12:447. [PMID: 30534055 PMCID: PMC6275320 DOI: 10.3389/fncel.2018.00447] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/07/2018] [Indexed: 12/27/2022] Open
Abstract
Neurite outgrowth underlies the wiring of the nervous system during development and regeneration. Despite a significant body of research, the underlying cytoskeletal mechanics of growth and guidance are not fully understood, and the relative contributions of individual cytoskeletal processes to neurite growth are controversial. Here, we review the structural organization and biophysical properties of neurons to make a semi-quantitative comparison of the relative contributions of different processes to neurite growth. From this, we develop the idea that neurons are active fluids, which generate strong contractile forces in the growth cone and weaker contractile forces along the axon. As a result of subcellular gradients in forces and material properties, actin flows rapidly rearward in the growth cone periphery, and microtubules flow forward in bulk along the axon. With this framework, an integrated model of neurite outgrowth is proposed that hopefully will guide new approaches to stimulate neuronal growth.
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Affiliation(s)
- Kyle E Miller
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
| | - Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States.,Bindley Bioscience Center, Purdue University, West Lafayette, IN, United States.,Birck Nanotechnology Center, Purdue University, West Lafayette, IN, United States
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76
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Kumamaru H, Lu P, Rosenzweig ES, Tuszynski MH. Activation of Intrinsic Growth State Enhances Host Axonal Regeneration into Neural Progenitor Cell Grafts. Stem Cell Reports 2018; 11:861-868. [PMID: 30197116 PMCID: PMC6178188 DOI: 10.1016/j.stemcr.2018.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 01/27/2023] Open
Abstract
Axonal regeneration after spinal cord injury (SCI) can be enhanced by activation of the intrinsic neuronal growth state and, separately, by placement of growth-enabling neural progenitor cell (NPC) grafts into lesion sites. Indeed, NPC grafts support regeneration of all host axonal projections innervating the normal spinal cord. However, some host axons regenerate only short distances into grafts. We examined whether activation of the growth state of the host injured neuron would elicit greater regeneration into NPC grafts. Rats received NPC grafts into SCI lesions in combination with peripheral "conditioning" lesions. Six weeks later, conditioned host sensory axons exhibited a significant, 9.6-fold increase in regeneration into the lesion/graft site compared with unconditioned axons. Regeneration was further enhanced 1.6-fold by enriching NPC grafts with phenotypically appropriate sensory neuronal targets. Thus, activation of the intrinsic host neuronal growth state and manipulation of the graft environment enhance axonal regeneration after SCI.
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Affiliation(s)
- Hiromi Kumamaru
- Department of Neurosciences, University of California - San Diego, 0626, La Jolla, CA 92093, USA
| | - Paul Lu
- Department of Neurosciences, University of California - San Diego, 0626, La Jolla, CA 92093, USA; Veterans Administration San Diego Healthcare System, San Diego, CA 92161, USA
| | - Ephron S Rosenzweig
- Department of Neurosciences, University of California - San Diego, 0626, La Jolla, CA 92093, USA
| | - Mark H Tuszynski
- Department of Neurosciences, University of California - San Diego, 0626, La Jolla, CA 92093, USA; Veterans Administration San Diego Healthcare System, San Diego, CA 92161, USA.
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Curcio M, Bradke F. Axon Regeneration in the Central Nervous System: Facing the Challenges from the Inside. Annu Rev Cell Dev Biol 2018; 34:495-521. [DOI: 10.1146/annurev-cellbio-100617-062508] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
After an injury in the adult mammalian central nervous system (CNS), lesioned axons fail to regenerate. This failure to regenerate contrasts with axons’ remarkable potential to grow during embryonic development and after an injury in the peripheral nervous system (PNS). Several intracellular mechanisms—including cytoskeletal dynamics, axonal transport and trafficking, signaling and transcription of regenerative programs, and epigenetic modifications—control axon regeneration. In this review, we describe how manipulation of intrinsic mechanisms elicits a regenerative response in different organisms and how strategies are implemented to form the basis of a future regenerative treatment after CNS injury.
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Affiliation(s)
- Michele Curcio
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany;,
| | - Frank Bradke
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany;,
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78
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Petrova V, Eva R. The Virtuous Cycle of Axon Growth: Axonal Transport of Growth-Promoting Machinery as an Intrinsic Determinant of Axon Regeneration. Dev Neurobiol 2018; 78:898-925. [PMID: 29989351 DOI: 10.1002/dneu.22608] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 02/02/2023]
Abstract
Injury to the brain and spinal cord has devastating consequences because adult central nervous system (CNS) axons fail to regenerate. Injury to the peripheral nervous system (PNS) has a better prognosis, because adult PNS neurons support robust axon regeneration over long distances. CNS axons have some regenerative capacity during development, but this is lost with maturity. Two reasons for the failure of CNS regeneration are extrinsic inhibitory molecules, and a weak intrinsic capacity for growth. Extrinsic inhibitory molecules have been well characterized, but less is known about the neuron-intrinsic mechanisms which prevent axon re-growth. Key signaling pathways and genetic/epigenetic factors have been identified which can enhance regenerative capacity, but the precise cellular mechanisms mediating their actions have not been characterized. Recent studies suggest that an important prerequisite for regeneration is an efficient supply of growth-promoting machinery to the axon; however, this appears to be lacking from non-regenerative axons in the adult CNS. In the first part of this review, we summarize the evidence linking axon transport to axon regeneration. We discuss the developmental decline in axon regeneration capacity in the CNS, and comment on how this is paralleled by a similar decline in the selective axonal transport of regeneration-associated receptors such as integrins and growth factor receptors. In the second part, we discuss the mechanisms regulating selective polarized transport within neurons, how these relate to the intrinsic control of axon regeneration, and whether they can be targeted to enhance regenerative capacity. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 00: 000-000, 2018.
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Affiliation(s)
- Veselina Petrova
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 OPY, United Kingdom
| | - Richard Eva
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 OPY, United Kingdom
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79
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Duncan GJ, Manesh SB, Hilton BJ, Assinck P, Liu J, Moulson A, Plemel JR, Tetzlaff W. Locomotor recovery following contusive spinal cord injury does not require oligodendrocyte remyelination. Nat Commun 2018; 9:3066. [PMID: 30076300 PMCID: PMC6076268 DOI: 10.1038/s41467-018-05473-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 06/28/2018] [Indexed: 12/16/2022] Open
Abstract
Remyelination occurs after spinal cord injury (SCI) but its functional relevance is unclear. We assessed the necessity of myelin regulatory factor (Myrf) in remyelination after contusive SCI by deleting the gene from platelet-derived growth factor receptor alpha positive (PDGFRα-positive) oligodendrocyte progenitor cells (OPCs) in mice prior to SCI. While OPC proliferation and density are not altered by Myrf inducible knockout after SCI, the accumulation of new oligodendrocytes is largely prevented. This greatly inhibits myelin regeneration, resulting in a 44% reduction in myelinated axons at the lesion epicenter. However, spontaneous locomotor recovery after SCI is not altered by remyelination failure. In controls with functional MYRF, locomotor recovery precedes the onset of most oligodendrocyte myelin regeneration. Collectively, these data demonstrate that MYRF expression in PDGFRα-positive cell derived oligodendrocytes is indispensable for myelin regeneration following contusive SCI but that oligodendrocyte remyelination is not required for spontaneous recovery of stepping.
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Affiliation(s)
- Greg J Duncan
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, V6T 1Z4, BC, Canada
| | - Sohrab B Manesh
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, 3402-2215 Wesbrook Mall, Vancouver, V6T 1Z3, BC, Canada
| | - Brett J Hilton
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, V6T 1Z4, BC, Canada
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Sigmund-Freud-Straße 27, 53127, Bonn, Germany
| | - Peggy Assinck
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada
- Graduate Program in Neuroscience, University of British Columbia, 3402-2215 Wesbrook Mall, Vancouver, V6T 1Z3, BC, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada
| | - Aaron Moulson
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, V6T 1Z4, BC, Canada
| | - Jason R Plemel
- The Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, T2N 4N1, Calgary, AB, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), 818 West 10th Avenue, V5Z 1M9, Vancouver, BC, Canada.
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, V6T 1Z4, BC, Canada.
- Department of Surgery, University of British Columbia, 2775 Laurel Street, Vancouver, V5Z 1M9, BC, Canada.
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80
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Ruschel J, Bradke F. Systemic administration of epothilone D improves functional recovery of walking after rat spinal cord contusion injury. Exp Neurol 2018; 306:243-249. [PMID: 29223322 DOI: 10.1016/j.expneurol.2017.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 10/28/2017] [Accepted: 12/04/2017] [Indexed: 01/31/2023]
Abstract
Central nervous system (CNS) injuries cause permanent impairments of sensorimotor functions as mature neurons fail to regenerate their severed axons. The poor intrinsic growth capacity of adult CNS neurons and the formation of an inhibitory lesion scar are key impediments to axon regeneration. Systemic administration of the microtubule stabilizing agent epothilone B promotes axon regeneration and recovery of motor function by activating the intrinsic axonal growth machinery and by reducing the inhibitory fibrotic lesion scar. Thus, epothilones hold clinical promise as potential therapeutics for spinal cord injury. Here we tested the efficacy of epothilone D, an epothilone B analog with a superior safety profile. By using liquid chromatography and mass spectrometry (LC/MS), we found adequate CNS penetration and distribution of epothilone D after systemic administration, confirming the suitability of the drug for non-invasive CNS treatment. Systemic administration of epothilone D reduced inhibitory fibrotic scarring, promoted regrowth of injured raphespinal fibers and improved walking function after mid-thoracic spinal cord contusion injury in adult rats. These results confirm that systemic administration of epothilones is a valuable therapeutic strategy for CNS regeneration and repair after injury and provides a further advance for potential clinical translation.
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Affiliation(s)
- Jörg Ruschel
- German Center for Neurodegenerative Diseases, Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
| | - Frank Bradke
- German Center for Neurodegenerative Diseases, Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
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81
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Abstract
Glial cell types were classified less than 100 years ago by del Rio-Hortega. For instance, he correctly surmised that microglia in pathologic central nervous system (CNS) were "voracious monsters" that helped clean the tissue. Although these historical predictions were remarkably accurate, innovative technologies have revealed novel molecular, cellular, and dynamic physiologic aspects of CNS glia. In this review, we integrate recent findings regarding the roles of glia and glial interactions in healthy and injured spinal cord. The three major glial cell types are considered in healthy CNS and after spinal cord injury (SCI). Astrocytes, which in the healthy CNS regulate neurotransmitter and neurovascular dynamics, respond to SCI by becoming reactive and forming a glial scar that limits pathology and plasticity. Microglia, which in the healthy CNS scan for infection/damage, respond to SCI by promoting axon growth and remyelination-but also with hyperactivation and cytotoxic effects. Oligodendrocytes and their precursors, which in healthy tissue speed axon conduction and support axonal function, respond to SCI by differentiating and producing myelin, but are susceptible to death. Thus, post-SCI responses of each glial cell can simultaneously stimulate and stifle repair. Interestingly, potential therapies could also target interactions between these cells. Astrocyte-microglia cross-talk creates a feed-forward loop, so shifting the response of either cell could amplify repair. Astrocytes, microglia, and oligodendrocytes/precursors also influence post-SCI cell survival, differentiation, and remyelination, as well as axon sparing. Therefore, optimizing post-SCI responses of glial cells-and interactions between these CNS cells-could benefit neuroprotection, axon plasticity, and functional recovery.
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Affiliation(s)
- Andrew D Gaudet
- Department of Psychology and Neuroscience, University of Colorado Boulder, Muenzinger D244 | 345 UCB, Boulder, CO, 80309, USA.
- Center for Neuroscience, University of Colorado Boulder, Muenzinger D244 | 345 UCB, Boulder, CO, 80309, USA.
| | - Laura K Fonken
- Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, TX, 78712, USA
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82
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Schaeffer J, Tannahill D, Cioni JM, Rowlands D, Keynes R. Identification of the extracellular matrix protein Fibulin-2 as a regulator of spinal nerve organization. Dev Biol 2018; 442:101-114. [PMID: 29944871 DOI: 10.1016/j.ydbio.2018.06.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 05/24/2018] [Accepted: 06/19/2018] [Indexed: 12/11/2022]
Abstract
During amniote peripheral nervous system development, segmentation ensures the correct patterning of the spinal nerves relative to the vertebral column. Along the antero-posterior (rostro-caudal) axis, each somite-derived posterior half-sclerotome expresses repellent molecules to restrict axon growth and neural crest migration to the permissive anterior half-segment. To identify novel regulators of spinal nerve patterning, we investigated the differential gene expression of anterior and posterior half-sclerotomes in the chick embryo by RNA-sequencing. Several genes encoding extracellular matrix proteins were found to be enriched in either anterior (e.g. Tenascin-C, Laminin alpha 4) or posterior (e.g. Fibulin-2, Fibromodulin, Collagen VI alpha 2) half-sclerotomes. Among them, the extracellular matrix protein Fibulin-2 was found specifically restricted to the posterior half-sclerotome. By using in ovo ectopic expression in chick somites, we found that Fibulin-2 modulates spinal axon growth trajectories in vivo. While no intrinsic axon repellent activity of Fibulin-2 was found, we showed that it enhances the growth cone repulsive activity of Semaphorin 3A in vitro. Some molecules regulating axon growth during development are found to be upregulated in the adult central nervous system (CNS) following traumatic injury. Here, we found increased Fibulin-2 protein levels in reactive astrocytes at the lesion site of a mouse model of CNS injury. Together, these results suggest that the developing vertebral column and the adult CNS share molecular features that control axon growth and plasticity, which may open up the possibility for the identification of novel therapeutic targets for brain and spinal cord injury.
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Affiliation(s)
- Julia Schaeffer
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK.
| | | | - Jean-Michel Cioni
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK
| | | | - Roger Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, UK
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83
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Li J, Li X, Xiao Z, Dai J. [Review of the regeneration mechanism of complete spinal cord injury]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2018; 32:641-649. [PMID: 29905039 DOI: 10.7507/1002-1892.201805069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Spinal cord injury (SCI), especially the complete SCI, usually results in complete paralysis below the level of the injury and seriously affects the patient's quality of life. SCI repair is still a worldwide medical problem. In the last twenty years, Professor DAI Jianwu and his team pioneered complete SCI model by removing spinal tissue with varied lengths in rodents, canine, and non-human primates to verify therapeutic effect of different repair strategies. Moreover, they also started the first clinical study of functional collagen scaffold on patients with acute complete SCI on January 16th, 2015. This review mainly focusses on the possible mechanisms responsible for complete SCI. In common, recovery of some sensory and motor functions post complete SCI include the following three contributing reasons. ① Regeneration of long ascending and descending axons throughout the lesion site to re-connect the original targets; ② New neural circuits formed in the lesion site by newly generated neurons post injury, which effectively re-connect the transected stumps; ③ The combined effect of ① and ②. The numerous studies have confirmed that neural circuits rebuilt across the injury site by newborn neurons might be the main mechanisms for functional recovery of animals from rodents to dogs. In many SCI model, especially the complete spinal cord transection model, many studies have convincingly demonstrated that the quantity and length of regenerated long descending axons, particularly like CST fibers, are too few to across the lesion site that is millimeters in length to realize motor functional recovery. Hence, it is more feasible in guiding neuronal relays formation by bio-scaffolds implantation than directing long motor axons regeneration in improving motor function of animals with complete spinal cord transection. However, some other issues such as promoting more neuronal relays formation, debugging wrong connections, and maintaining adequate neural circuits for functional recovery are urgent problems to be addressed.
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Affiliation(s)
- Jiayin Li
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,P.R.China
| | - Xing Li
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,P.R.China
| | - Zhifeng Xiao
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,P.R.China
| | - Jianwu Dai
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,
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84
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Abstract
Adult central nervous system (CNS) axons do not regenerate after injury because of extrinsic inhibitory factors, and a low intrinsic capacity for axon growth. Developing CNS neurons have a better regenerative ability, but lose this with maturity. This mini-review summarises recent findings which suggest one reason for regenerative failure is the selective distribution of growth machinery away from axons as CNS neurons mature. These studies demonstrate roles for the small GTPases ARF6 and Rab11 as intrinsic regulators of polarised transport and axon regeneration. ARF6 activation prevents the axonal transport of integrins in Rab11 endosomes in mature CNS axons. Decreasing ARF6 activation permits axonal transport, and increases regenerative ability. The findings suggest new targets for promoting axon regeneration after CNS injury.
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Affiliation(s)
- Bart Nieuwenhuis
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge , Forvie Site, Robinson Way, Cambridge, UK.,Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW) , Amsterdam, The Netherlands
| | - Richard Eva
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge , Forvie Site, Robinson Way, Cambridge, UK
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85
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Vagnozzi AN, Silver J. Targeting the cytoskeleton with an FDA approved drug to promote recovery after spinal cord injury. Exp Neurol 2018; 306:260-262. [PMID: 29752944 DOI: 10.1016/j.expneurol.2018.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Alicia N Vagnozzi
- Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH 44106, USA
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH 44106, USA.
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86
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Senger JLB, Verge VMK, Chan KM, Webber CA. The nerve conditioning lesion: A strategy to enhance nerve regeneration. Ann Neurol 2018. [DOI: 10.1002/ana.25209] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | - Valerie M. K. Verge
- Department of Anatomy and Cell Biology, and Cameco MS Neuroscience Research Center; University of Saskatchewan; Saskatoon Saskatchewan
| | - K. Ming Chan
- Department of Physical Rehabilitation; University of Alberta; Edmonton Alberta Canada
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87
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88
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Blanquie O, Bradke F. Cytoskeleton dynamics in axon regeneration. Curr Opin Neurobiol 2018; 51:60-69. [PMID: 29544200 DOI: 10.1016/j.conb.2018.02.024] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/22/2018] [Accepted: 02/26/2018] [Indexed: 11/19/2022]
Abstract
Recent years have seen cytoskeleton dynamics emerging as a key player in axon regeneration. The cytoskeleton, in particular microtubules and actin, ensures the growth of neuronal processes and maintains the singular, highly polarized shape of neurons. Following injury, adult central axons are tipped by a dystrophic structure, the retraction bulb, which prevents their regeneration. Abnormal cytoskeleton dynamics are responsible for the formation of this growth-incompetent structure but pharmacologically modulating cytoskeleton dynamics of injured axons can transform this structure into a growth-competent growth cone. The cytoskeleton also drives the migration of scar-forming cells after an injury. Targeting its dynamics modifies the composition of the inhibitory environment formed by scar tissue and renders it more permissive for regenerating axons. Hence, cytoskeleton dynamics represent an appealing target to promote axon regeneration. As some of cytoskeleton-targeting drugs are used in the clinics for other purposes, they hold the promise to be used as a basis for a regenerative therapy after a spinal cord injury.
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Affiliation(s)
- Oriane Blanquie
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
| | - Frank Bradke
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
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89
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3D axon growth by exogenous electrical stimulus and soluble factors. Brain Res 2018; 1678:288-296. [DOI: 10.1016/j.brainres.2017.10.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 10/28/2017] [Indexed: 11/24/2022]
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