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Ryan F, Francos-Quijorna I, Hernández-Mir G, Aquino C, Schlapbach R, Bradbury EJ, David S. Tlr4 Deletion Modulates Cytokine and Extracellular Matrix Expression in Chronic Spinal Cord Injury, Leading to Improved Secondary Damage and Functional Recovery. J Neurosci 2024; 44:e0778232023. [PMID: 38326029 PMCID: PMC10860514 DOI: 10.1523/jneurosci.0778-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 11/03/2023] [Accepted: 11/12/2023] [Indexed: 02/09/2024] Open
Abstract
Toll-like receptors (TLRs) play an important role in the innate immune response after CNS injury. Although TLR4 is one of the best characterized, its role in chronic stages after spinal cord injury (SCI) is not well understood. We examined the role of TLR4 signaling in injury-induced responses at 1 d, 7 d, and 8 weeks after spinal cord contusion injury in adult female TLR4 null and wild-type mice. Analyses include secondary damage, a range of transcriptome and protein analyses of inflammatory, cell death, and extracellular matrix (ECM) molecules, as well as immune cell infiltration and changes in axonal sprouting and locomotor recovery. Lack of TLR4 signaling results in reduced neuronal and myelin loss, reduced activation of NFκB, and decreased expression of inflammatory cytokines and necroptotic cell death pathway at a late time point (8 weeks) after injury. TLR4 null mice also showed reduction of scar-related ECM molecules at 8 weeks after SCI, accompanied by increase in ECM molecules associated with perineuronal nets, increased sprouting of serotonergic fibers, and improved locomotor recovery. These findings reveal novel effects of TLR4 signaling in chronic SCI. We show that TLR4 influences inflammation, cell death, and ECM deposition at late-stage post-injury when secondary injury processes are normally considered to be over. This highlights the potential for late-stage targeting of TLR4 as a potential therapy for chronic SCI.
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Affiliation(s)
- Fari Ryan
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada
| | - Isaac Francos-Quijorna
- The Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Gerard Hernández-Mir
- Centre for Immunobiology, Blizard Institute, Barts and The London School of Medicine, Queen Mary University of London, London E1 2AT, United Kingdom
| | - Catharine Aquino
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich 8057, Switzerland
| | - Ralph Schlapbach
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich 8057, Switzerland
| | - Elizabeth J Bradbury
- The Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Samuel David
- Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada
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Berzanskyte I, Riccio F, Machado CB, Bradbury EJ, Lieberam I. Enrichment of human embryonic stem cell-derived V3 interneurons using an Nkx2-2 gene-specific reporter. Sci Rep 2023; 13:2008. [PMID: 36737643 PMCID: PMC9898512 DOI: 10.1038/s41598-023-29165-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
V3 spinal interneurons are a key element of the spinal circuits, which control motor function. However, to date, there are no effective ways of deriving a pure V3 population from human pluripotent stem cells. Here, we report a method for differentiation and isolation of spinal V3 interneurons, combining extrinsic factor-mediated differentiation and magnetic activated cell sorting. We found that differentiation of V3 progenitors can be enhanced with a higher concentration of Sonic Hedgehog agonist, as well as culturing cells in 3D format. To enable V3 progenitor purification from mixed differentiation cultures, we developed a transgene reporter, with a part of the regulatory region of V3-specific gene Nkx2-2 driving the expression of a membrane marker CD14. We found that in human cells, NKX2-2 initially exhibited co-labelling with motor neuron progenitor marker, but V3 specificity emerged as the differentiation culture progressed. At these later differentiation timepoints, we were able to enrich V3 progenitors labelled with CD14 to ~ 95% purity, and mature them to postmitotic V3 interneurons. This purification tool for V3 interneurons will be useful for in vitro disease modeling, studies of normal human neural development and potential cell therapies for disorders of the spinal cord.
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Affiliation(s)
- Ieva Berzanskyte
- Centre for Gene Therapy and Regenerative Medicine, Centre for Developmental Neurobiology, MRC Centre for Neurodevelopmental Disorders, King's College London, 28th Floor Tower Wing, Guy's Campus, Great Maze Pond, London, SE1 9RT, UK.
- The Wolfson Centre for Age-Related Diseases, King's College London, London, UK.
| | - Federica Riccio
- Centre for Gene Therapy and Regenerative Medicine, Centre for Developmental Neurobiology, MRC Centre for Neurodevelopmental Disorders, King's College London, 28th Floor Tower Wing, Guy's Campus, Great Maze Pond, London, SE1 9RT, UK
| | - Carolina Barcellos Machado
- Centre for Gene Therapy and Regenerative Medicine, Centre for Developmental Neurobiology, MRC Centre for Neurodevelopmental Disorders, King's College London, 28th Floor Tower Wing, Guy's Campus, Great Maze Pond, London, SE1 9RT, UK
| | | | - Ivo Lieberam
- Centre for Gene Therapy and Regenerative Medicine, Centre for Developmental Neurobiology, MRC Centre for Neurodevelopmental Disorders, King's College London, 28th Floor Tower Wing, Guy's Campus, Great Maze Pond, London, SE1 9RT, UK.
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Smith GM, Steward O, Bradbury EJ. Gene modification after spinal cord injury: Mechanisms and therapeutics. Exp Neurol 2022; 356:114156. [DOI: 10.1016/j.expneurol.2022.114156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Sinopoulou E, Spejo AB, Roopnarine N, Burnside ER, Bartus K, De Winter F, McMahon SB, Bradbury EJ. Chronic muscle recordings reveal recovery of forelimb function in spinal injured female rats after cortical epidural stimulation combined with rehabilitation and chondroitinase ABC. J Neurosci Res 2022; 100:2055-2076. [PMID: 35916483 PMCID: PMC9544922 DOI: 10.1002/jnr.25111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 06/23/2022] [Accepted: 07/09/2022] [Indexed: 11/11/2022]
Abstract
Cervical level spinal cord injury (SCI) can severely impact upper limb muscle function, which is typically assessed in the clinic using electromyography (EMG). Here, we established novel preclinical methodology for EMG assessments of muscle function after SCI in awake freely moving animals. Adult female rats were implanted with EMG recording electrodes in bicep muscles and received bilateral cervical (C7) contusion injuries. Forelimb muscle activity was assessed by recording maximum voluntary contractions during a grip strength task and cortical motor evoked potentials in the biceps. We demonstrate that longitudinal recordings of muscle activity in the same animal are feasible over a chronic post-injury time course and provide a sensitive method for revealing post-injury changes in muscle activity. This methodology was utilized to investigate recovery of muscle function after a novel combination therapy. Cervical contused animals received intraspinal injections of a neuroplasticity-promoting agent (lentiviral-chondroitinase ABC) plus 11 weeks of cortical epidural electrical stimulation (3 h daily, 5 days/week) and behavioral rehabilitation (15 min daily, 5 days/week). Longitudinal monitoring of voluntary and evoked muscle activity revealed significantly increased muscle activity and upper limb dexterity with the combination treatment, compared to a single treatment or no treatment. Retrograde mapping of motor neurons innervating the biceps showed a predominant distribution across spinal segments C5-C8, indicating that treatment effects were likely due to neuroplastic changes in a mixture of intact and injured motor neurons. Thus, longitudinal assessments of muscle function after SCI correlate with skilled reach and grasp performance and reveal functional benefits of a novel combination therapy.
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Affiliation(s)
- Eleni Sinopoulou
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK.,Department of Neuroscience, The Center for Neural Repair, University of California, San Diego, California, USA
| | - Aline Barroso Spejo
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK
| | - Naomi Roopnarine
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK
| | - Emily R Burnside
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK
| | - Katalin Bartus
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK
| | - Fred De Winter
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Stephen B McMahon
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK
| | - Elizabeth J Bradbury
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, London, UK
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Jevans B, James ND, Burnside E, McCann CJ, Thapar N, Bradbury EJ, Burns AJ. Combined treatment with enteric neural stem cells and chondroitinase ABC reduces spinal cord lesion pathology. Stem Cell Res Ther 2021; 12:10. [PMID: 33407795 PMCID: PMC7789480 DOI: 10.1186/s13287-020-02031-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 11/16/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Spinal cord injury (SCI) presents a significant challenge for the field of neurotherapeutics. Stem cells have shown promise in replenishing the cells lost to the injury process, but the release of axon growth-inhibitory molecules such as chondroitin sulfate proteoglycans (CSPGs) by activated cells within the injury site hinders the integration of transplanted cells. We hypothesised that simultaneous application of enteric neural stem cells (ENSCs) isolated from the gastrointestinal tract, with a lentivirus (LV) containing the enzyme chondroitinase ABC (ChABC), would enhance the regenerative potential of ENSCs after transplantation into the injured spinal cord. METHODS ENSCs were harvested from the GI tract of p7 rats, expanded in vitro and characterised. Adult rats bearing a contusion injury were randomly assigned to one of four groups: no treatment, LV-ChABC injection only, ENSC transplantation only or ENSC transplantation+LV-ChABC injection. After 16 weeks, rats were sacrificed and the harvested spinal cords examined for evidence of repair. RESULTS ENSC cultures contained a variety of neuronal subtypes suitable for replenishing cells lost through SCI. Following injury, transplanted ENSC-derived cells survived and ChABC successfully degraded CSPGs. We observed significant reductions in the injured tissue and cavity area, with the greatest improvements seen in the combined treatment group. ENSC-derived cells extended projections across the injury site into both the rostral and caudal host spinal cord, and ENSC transplantation significantly increased the number of cells extending axons across the injury site. Furthermore, the combined treatment resulted in a modest, but significant functional improvement by week 16, and we found no evidence of the spread of transplanted cells to ectopic locations or formation of tumours. CONCLUSIONS Regenerative effects of a combined treatment with ENSCs and ChABC surpassed either treatment alone, highlighting the importance of further research into combinatorial therapies for SCI. Our work provides evidence that stem cells taken from the adult gastrointestinal tract, an easily accessible source for autologous transplantation, could be strongly considered for the repair of central nervous system disorders.
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Affiliation(s)
- Benjamin Jevans
- Stem Cells and Regenerative Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
- Present Address: German Centre for Neurodegenerative diseases (DZNE), Bonn, Germany
| | - Nicholas D James
- Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, King's College London, Guy's Campus, London, UK
| | - Emily Burnside
- Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, King's College London, Guy's Campus, London, UK
| | - Conor J McCann
- Stem Cells and Regenerative Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Nikhil Thapar
- Stem Cells and Regenerative Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
- Neurogastroenterology and Motility Unit, Department of Gastroenterology, Great Ormond Street Hospital, London, UK
- Present Address: Department of Paediatric Gastroenterology, Hepatology and Liver Transplant, Queensland Children's Hospital, Brisbane, Australia
| | - Elizabeth J Bradbury
- Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, King's College London, Guy's Campus, London, UK
| | - Alan J Burns
- Stem Cells and Regenerative Medicine, UCL Great Ormond Street Institute of Child Health, London, UK.
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.
- Present Address: Gastrointestinal Drug Discovery Unit, Takeda Pharmaceuticals International, Cambridge, USA.
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Strotton MC, Bodey AJ, Wanelik K, Hobbs C, Rau C, Bradbury EJ. The spatiotemporal spread of cervical spinal cord contusion injury pathology revealed by 3D in-line phase contrast synchrotron X-ray microtomography. Exp Neurol 2020; 336:113529. [PMID: 33220238 PMCID: PMC7840595 DOI: 10.1016/j.expneurol.2020.113529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/26/2020] [Accepted: 11/12/2020] [Indexed: 12/11/2022]
Abstract
Extensive structural changes occur within the spinal cord following traumatic injury. Acute tissue debris and necrotic tissue are broken down, proliferating local glia and infiltrating leukocytes remodel tissue biochemical and biophysical properties, and a chronic cavity surrounded by a scar forms at the injury epicentre. Serial-section 2D histology has traditionally assessed these features in experimental models of spinal cord injury (SCI) to measure the extent of tissue pathology and evaluate efficacy of novel therapies. However, this 2D snapshot approach overlooks slice intervening features, with accurate representation of tissue compromised by mechanical processing artefacts. 3D imaging avoids these caveats and allows full exploration of the injured tissue volume to characterise whole tissue pathology. Amongst 3D imaging modalities, Synchrotron Radiation X-ray microtomography (SRμCT) is advantageous for its speed, ability to cover large tissue volumes at high resolution, and need for minimal sample processing. Here we demonstrate how extended lengths of formalin-fixed, paraffin-embedded (FFPE) rat spinal cord can be completely imaged by SRμCT with micron resolution. Label-free contrast derived from X-ray phase interactions with low-density soft tissues, reveals spinal cord white matter, gray matter, tissue damage and vasculature, with tissue still viable for targeted 2D-histology after 3D imaging. We used SRμCT to quantify tissue pathology after a midline, cervical level (C6), 225 kDyne contusion injury over acute-to-chronic (24 h to 5 weeks) post injury time points. Quantification revealed acute tissue swelling prior to chronic atrophy across the whole imaged region (spanning 2 spinal segments above and below injury), along with rostro-caudal asymmetries in white and gray matter volume loss. 3D volumes revealed satellite damage in tissue far removed from the epicentre, and extensive rostro-caudal spread of damage through the base of the dorsal columns at 24 h post injury. This damage overlapped regions of vasogenic oedema, confirmed with subsequent histology. Tissue damage at later time points in border regions was most prominent in the dorsal columns, where it overlapped sites of damaged venous vasculature. Elaborating rostro-caudal and spatiotemporal asymmetries in reduced traumatic injury models centred on these regions may inform future treatments that seek to limit the spread of tissue pathology to these ‘at-risk’ regions. Whole rat spinal cord SRμCT tomograms (up to 20 mm length) with μm resolution Pathology of 3 SHAM and 24 acute-to-chronic C6 midline contusion SCIs quantified Rostro-caudal asymmetries in gray and white matter pathology progression Differences in ascending and descending dorsal column tract pathology Delayed rostral-caudal pathology associated with sites of venous vasculature
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Affiliation(s)
- Merrick C Strotton
- King's College London, Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, Guy's Campus, London Bridge, London SE1 1UL, UK.
| | | | | | - Carl Hobbs
- King's College London, Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, Guy's Campus, London Bridge, London SE1 1UL, UK.
| | | | - Elizabeth J Bradbury
- King's College London, Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology & Neuroscience, Guy's Campus, London Bridge, London SE1 1UL, UK.
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Warren PM, Andrews MR, Smith M, Bartus K, Bradbury EJ, Verhaagen J, Fawcett JW, Kwok JCF. Secretion of a mammalian chondroitinase ABC aids glial integration at PNS/CNS boundaries. Sci Rep 2020; 10:11262. [PMID: 32647242 PMCID: PMC7347606 DOI: 10.1038/s41598-020-67526-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/26/2020] [Indexed: 12/13/2022] Open
Abstract
Schwann cell grafts support axonal growth following spinal cord injury, but a boundary forms between the implanted cells and host astrocytes. Axons are reluctant to exit the graft tissue in large part due to the surrounding inhibitory environment containing chondroitin sulphate proteoglycans (CSPGs). We use a lentiviral chondroitinase ABC, capable of being secreted from mammalian cells (mChABC), to examine the repercussions of CSPG digestion upon Schwann cell behaviour in vitro. We show that mChABC transduced Schwann cells robustly secrete substantial quantities of the enzyme causing large-scale CSPG digestion, facilitating the migration and adhesion of Schwann cells on inhibitory aggrecan and astrocytic substrates. Importantly, we show that secretion of the engineered enzyme can aid the intermingling of cells at the Schwann cell-astrocyte boundary, enabling growth of neurites over the putative graft/host interface. These data were echoed in vivo. This study demonstrates the profound effect of the enzyme on cellular motility, growth and migration. This provides a cellular mechanism for mChABC induced functional and behavioural recovery shown in in vivo studies. Importantly, we provide in vitro evidence that mChABC gene therapy is equally or more effective at producing these effects as a one-time application of commercially available ChABC.
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Affiliation(s)
- Philippa M Warren
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Cambridge, CB2 0PY, UK. .,Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London Bridge, London, SE1 1UL, UK. .,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 0PY, UK.
| | - Melissa R Andrews
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Cambridge, CB2 0PY, UK.,Faculty of Environmental and Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Marc Smith
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Katalin Bartus
- Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Elizabeth J Bradbury
- Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Joost Verhaagen
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - James W Fawcett
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Cambridge, CB2 0PY, UK.,Centre for Reconstructive Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic
| | - Jessica C F Kwok
- Centre for Reconstructive Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic.,School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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Eggers R, de Winter F, Smit L, Luimens M, Muir EM, Bradbury EJ, Tannemaat MR, Verhaagen J. Combining timed GDNF and ChABC gene therapy to promote long-distance regeneration following ventral root avulsion and repair. FASEB J 2020; 34:10605-10622. [PMID: 32543730 DOI: 10.1096/fj.202000559r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/18/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022]
Abstract
Ventral root avulsion leads to severe motoneuron degeneration and prolonged distal nerve denervation. After a critical period, a state of chronic denervation develops as repair Schwann cells lose their pro-regenerative properties and inhibitory factors such as CSPGs accumulate in the denervated nerve. In rats with ventral root avulsion injuries, we combined timed GDNF gene therapy delivered to the proximal nerve roots with the digestion of inhibitory CSPGs in the distal denervated nerve using sustained lentiviral-mediated chondroitinase ABC (ChABC) enzyme expression. Following reimplantation of lumbar ventral roots, timed GDNF-gene therapy enhanced motoneuron survival up to 45 weeks and improved axonal outgrowth, electrophysiological recovery, and muscle reinnervation. Despite a timed GDNF expression period, a subset of animals displayed axonal coils. Lentiviral delivery of ChABC enabled digestion of inhibitory CSPGs for up to 45 weeks in the chronically denervated nerve. ChABC gene therapy alone did not enhance motoneuron survival, but led to improved muscle reinnervation and modest electrophysiological recovery during later stages of the regeneration process. Combining GDNF treatment with digestion of inhibitory CSPGs did not have a significant synergistic effect. This study suggests a delicate balance exists between treatment duration and concentration in order to achieve therapeutic effects.
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Affiliation(s)
- Ruben Eggers
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Fred de Winter
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Lotte Smit
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Maruelle Luimens
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Elizabeth M Muir
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), London, UK
| | - Martijn R Tannemaat
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands.,Department of Neurology, Leiden University Medical Center, Leiden, the Netherlands
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands.,Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognition Research, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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Bradbury EJ, Oliveira R. Inhibiting an inhibitor: a decoy to recover dexterity after spinal cord injury. Brain 2020; 143:1618-1622. [PMID: 32543695 PMCID: PMC7296859 DOI: 10.1093/brain/awaa175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This scientific commentary refers to ‘Nogo receptor decoy promotes recovery and corticospinal growth in non-human primate spinal cord injury’, by Wang et al. (doi:10.1093/brain/awaa116).
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Affiliation(s)
- Elizabeth J Bradbury
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, London, UK
| | - Raquel Oliveira
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, London, UK
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10
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Lilley E, Andrews MR, Bradbury EJ, Elliott H, Hawkins P, Ichiyama RM, Keeley J, Michael-Titus AT, Moon LDF, Pluchino S, Riddell J, Ryder K, Yip PK. Refining rodent models of spinal cord injury. Exp Neurol 2020; 328:113273. [PMID: 32142803 DOI: 10.1016/j.expneurol.2020.113273] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 01/16/2023]
Abstract
This report was produced by an Expert Working Group (EWG) consisting of UK-based researchers, veterinarians and regulators of animal experiments with specialist knowledge of the use of animal models of spinal cord injury (SCI). It aims to facilitate the implementation of the Three Rs (Replacement, Reduction and Refinement), with an emphasis on refinement. Specific animal welfare issues were identified and discussed, and practical measures proposed, with the aim of reducing animal use and suffering, reducing experimental variability, and increasing translatability within this critically important research field.
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Affiliation(s)
- Elliot Lilley
- Research Animals Department, Royal Society for the Prevention of Cruelty to Animals, Wilberforce Way, Southwater, Horsham, West Sussex RH13 9RS, UK.
| | - Melissa R Andrews
- Biological Sciences, University of Southampton, 3059, Life Sciences Bldg 85, Highfield Campus, Southampton SO17 1BJ, UK.
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London SE1 1UL, UK.
| | - Heather Elliott
- Animals in Scientific Research Unit, 14th Floor, Lunar House, 40 Wellesley Road, Croydon CR9 2BY, UK.
| | - Penny Hawkins
- Research Animals Department, Royal Society for the Prevention of Cruelty to Animals, Wilberforce Way, Southwater, Horsham, West Sussex RH13 9RS, UK.
| | - Ronaldo M Ichiyama
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, UK.
| | - Jo Keeley
- University Biomedical Services, University of Cambridge, Greenwich House, Madingley Rise, Madingley Road, Cambridge CB3 0TX, UK.
| | - Adina T Michael-Titus
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark St, London E1 2AT, UK.
| | - Lawrence D F Moon
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London SE1 1UL, UK.
| | - Stefano Pluchino
- University Biomedical Services, University of Cambridge, Greenwich House, Madingley Rise, Madingley Road, Cambridge CB3 0TX, UK.
| | - John Riddell
- Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Kathy Ryder
- Animals in Scientific Research Unit, 14th Floor, Lunar House, 40 Wellesley Road, Croydon CR9 2BY, UK.
| | - Ping K Yip
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark St, London E1 2AT, UK.
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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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12
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Burnside ER, De Winter F, Didangelos A, James ND, Andreica EC, Layard-Horsfall H, Muir EM, Verhaagen J, Bradbury EJ. Immune-evasive gene switch enables regulated delivery of chondroitinase after spinal cord injury. Brain 2019; 141:2362-2381. [PMID: 29912283 PMCID: PMC6061881 DOI: 10.1093/brain/awy158] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/22/2018] [Indexed: 12/12/2022] Open
Abstract
Chondroitinase ABC is a promising preclinical therapy that promotes functional neuroplasticity after CNS injury by degrading extracellular matrix inhibitors. Efficient delivery of chondroitinase ABC to the injured mammalian spinal cord can be achieved by viral vector transgene delivery. This approach dramatically modulates injury pathology and restores sensorimotor functions. However, clinical development of this therapy is limited by a lack of ability to exert control over chondroitinase gene expression. Prior experimental gene regulation platforms are likely to be incompatible with the non-resolving adaptive immune response known to occur following spinal cord injury. Therefore, here we apply a novel immune-evasive dual vector system, in which the chondroitinase gene is under a doxycycline inducible regulatory switch, utilizing a chimeric transactivator designed to evade T cell recognition. Using this novel vector system, we demonstrate tight temporal control of chondroitinase ABC gene expression, effectively removing treatment upon removal of doxycycline. This enables a comparison of short and long-term gene therapy paradigms in the treatment of clinically-relevant cervical level contusion injuries in adult rats. We reveal that transient treatment (2.5 weeks) is sufficient to promote improvement in sensory axon conduction and ladder walking performance. However, in tasks requiring skilled reaching and grasping, only long term treatment (8 weeks) leads to significantly improved function, with rats able to accurately grasp and retrieve sugar pellets. The late emergence of skilled hand function indicates enhanced neuroplasticity and connectivity and correlates with increased density of vGlut1+ innervation in spinal cord grey matter, particularly in lamina III–IV above and below the injury. Thus, our novel gene therapy system provides an experimental tool to study temporal effects of extracellular matrix digestion as well as an encouraging step towards generating a safer chondroitinase gene therapy strategy, longer term administration of which increases neuroplasticity and recovery of descending motor control. This preclinical study could have a significant impact for tetraplegic individuals, for whom recovery of hand function is an important determinant of independence, and supports the ongoing development of chondroitinase gene therapy towards clinical application for the treatment of spinal cord injury.
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Affiliation(s)
- Emily R Burnside
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Fred De Winter
- Netherlands Institute for Neuroscience, Laboratory for Neuroregeneration, 1105 BA Amsterdam, The Netherlands
| | - Athanasios Didangelos
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Nicholas D James
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Elena-Cristina Andreica
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Hugo Layard-Horsfall
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
| | - Elizabeth M Muir
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB2 3EG, UK
| | - Joost Verhaagen
- Netherlands Institute for Neuroscience, Laboratory for Neuroregeneration, 1105 BA Amsterdam, The Netherlands
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
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13
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Bartus K, Burnside ER, Galino J, James ND, Bennett DLH, Bradbury EJ. ErbB receptor signaling directly controls oligodendrocyte progenitor cell transformation and spontaneous remyelination after spinal cord injury. Glia 2019; 67:1036-1046. [PMID: 30637799 PMCID: PMC6491970 DOI: 10.1002/glia.23586] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/14/2018] [Accepted: 12/20/2018] [Indexed: 01/09/2023]
Abstract
We recently discovered a novel role for neuregulin‐1 (Nrg1) signaling in mediating spontaneous regenerative processes and functional repair after spinal cord injury (SCI). We revealed that Nrg1 is the molecular signal responsible for spontaneous functional remyelination of dorsal column axons by peripheral nervous system (PNS)‐like Schwann cells after SCI. Here, we investigate whether Nrg1/ErbB signaling controls the unusual transformation of centrally derived progenitor cells into these functional myelinating Schwann cells after SCI using a fate‐mapping/lineage tracing approach. Specific ablation of Nrg1‐ErbB receptors in central platelet‐derived growth factor receptor alpha (PDGFRα)‐derived lineage cells (using PDGFRαCreERT2/Tomato‐red reporter mice crossed with ErbB3fl/fl/ErbB4fl/fl mice) led to a dramatic reduction in P0‐positive remyelination in the dorsal columns following spinal contusion injury. Central myelination, assessed by Olig2 and proteolipid protein expression, was unchanged. Loss of ErbB signaling in PDGFRα lineage cells also significantly impacted the degree of spontaneous locomotor recovery after SCI, particularly in tests dependent on proprioception. These data have important implications, namely (a) cells from the PDGFRα‐expressing progenitor lineage (which are presumably oligodendrocyte progenitor cells, OPCs) can differentiate into remyelinating PNS‐like Schwann cells after traumatic SCI, (b) this process is controlled by ErbB tyrosine kinase signaling, and (c) this endogenous repair mechanism has significant consequences for functional recovery after SCI. Thus, ErbB tyrosine kinase receptor signaling directly controls the transformation of OPCs from the PDGFRα‐expressing lineage into PNS‐like functional remyelinating Schwann cells after SCI.
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Affiliation(s)
- Katalin Bartus
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), London, United Kingdom
| | - Emily R Burnside
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), London, United Kingdom
| | - Jorge Galino
- Nuffield Department of Clinical Neurosciences, West Wing John Radcliffe Hospital, Oxford, United Kingdom
| | - Nicholas D James
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), London, United Kingdom
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, West Wing John Radcliffe Hospital, Oxford, United Kingdom
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), London, United Kingdom
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14
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James ND, McMahon SB, Field-Fote EC, Bradbury EJ. Neuromodulation in the restoration of function after spinal cord injury. Lancet Neurol 2018; 17:905-917. [PMID: 30264729 DOI: 10.1016/s1474-4422(18)30287-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 07/12/2018] [Accepted: 07/19/2018] [Indexed: 12/13/2022]
Abstract
Neuromodulation, the use of electrical interfaces to alter neuronal activity, has been successful as a treatment approach in several neurological disorders, including deep brain stimulation for Parkinson's disease and epidural spinal stimulation for chronic pain. Neuromodulation can also be beneficial for spinal cord injury, from assisting basic functions such as respiratory pacing and bladder control, through to restoring volitional movements and skilled hand function. Approaches range from electrical stimulation of peripheral muscles, either directly or via brain-controlled bypass devices, to stimulation of the spinal cord and brain. Limitations to widespread clinical application include durability of neuromodulation devices, affordability and accessibility of some approaches, and poor understanding of the underlying mechanisms. Efforts to overcome these challenges through advances in technology, together with pragmatic knowledge gained from clinical trials and basic research, could lead to personalised neuromodulatory interventions to meet the specific needs of individuals with spinal cord injury.
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Affiliation(s)
- Nicholas D James
- Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, King's College London, London, UK; Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology, Lausanne, Switzerland
| | - Stephen B McMahon
- Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, King's College London, London, UK
| | - Edelle C Field-Fote
- Shepherd Center, Crawford Research Institute, Atlanta, GA, USA; Division of Physical Therapy, Emory University School of Medicine, Atlanta, GA, USA; Georgia Institute of Technology, School of Biological Sciences, Program in Applied Physiology, Atlanta, GA, USA
| | - Elizabeth J Bradbury
- Regeneration Group, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, King's College London, London, UK.
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15
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Tica J, Bradbury EJ, Didangelos A. Combined Transcriptomics, Proteomics and Bioinformatics Identify Drug Targets in Spinal Cord Injury. Int J Mol Sci 2018; 19:E1461. [PMID: 29758010 PMCID: PMC5983596 DOI: 10.3390/ijms19051461] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/06/2018] [Accepted: 04/09/2018] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) causes irreversible tissue damage and severe loss of neurological function. Currently, there are no approved treatments and very few therapeutic targets are under investigation. Here, we combined 4 high-throughput transcriptomics and proteomics datasets, 7 days and 8 weeks following clinically-relevant rat SCI to identify proteins with persistent differential expression post-injury. Out of thousands of differentially regulated entities our combined analysis identified 40 significantly upregulated versus 48 significantly downregulated molecules, which were persistently altered at the mRNA and protein level, 7 days and 8 weeks post-SCI. Bioinformatics analysis was then utilized to identify currently available drugs with activity against the filtered molecules and to isolate proteins with known or unknown function in SCI. Our findings revealed multiple overlooked therapeutic candidates with important bioactivity and established druggability but with unknown expression and function in SCI including the upregulated purine nucleoside phosphorylase (PNP), cathepsins A, H, Z (CTSA, CTSH, CTSZ) and proteasome protease PSMB10, as well as the downregulated ATP citrate lyase (ACLY), malic enzyme (ME1) and sodium-potassium ATPase (ATP1A3), amongst others. This work reveals previously unappreciated therapeutic candidates for SCI and available drugs, thus providing a valuable resource for further studies and potential repurposing of existing therapeutics for SCI.
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Affiliation(s)
- Jure Tica
- Imperial College London, Alexander Fleming Building, London SW7 2AZ, UK.
| | - Elizabeth J Bradbury
- King's College London, Wolfson CARD, Institute of Psychiatry, Psychology & Neuroscience, London SE1 1UL, UK.
| | - Athanasios Didangelos
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 7RH, UK.
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16
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17
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James ND, Angéria M, Bradbury EJ, Damberg P, McMahon SB, Risling M, Carlstedt T. Structural and Functional Substitution of Deleted Primary Sensory Neurons by New Growth from Intrinsic Spinal Cord Nerve Cells: An Alternative Concept in Reconstruction of Spinal Cord Circuits. Front Neurol 2017; 8:358. [PMID: 28790970 PMCID: PMC5523078 DOI: 10.3389/fneur.2017.00358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/07/2017] [Indexed: 11/13/2022] Open
Abstract
In a recent clinical report, return of the tendon stretch reflex was demonstrated after spinal cord surgery in a case of total traumatic brachial plexus avulsion injury. Peripheral nerve grafts had been implanted into the spinal cord to reconnect to the peripheral nerves for motor and sensory function. The dorsal root ganglia (DRG) containing the primary sensory nerve cells had been surgically removed in order for secondary or spinal cord sensory neurons to extend into the periphery and replace the deleted DRG neurons. The present experimental study uses a rat injury model first to corroborate the clinical finding of a re-established spinal reflex arch, and second, to elucidate some of the potential mechanisms underlying these findings by means of morphological, immunohistochemical, and electrophysiological assessments. Our findings indicate that, after spinal cord surgery, the central nervous system sensory system could replace the traumatically detached original peripheral sensory connections through new neurite growth from dendrites.
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Affiliation(s)
- Nicholas D James
- The Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Maria Angéria
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Elizabeth J Bradbury
- The Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Peter Damberg
- Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Stephen B McMahon
- The Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Thomas Carlstedt
- The Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
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18
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Moeendarbary E, Weber IP, Sheridan GK, Koser DE, Soleman S, Haenzi B, Bradbury EJ, Fawcett J, Franze K. The soft mechanical signature of glial scars in the central nervous system. Nat Commun 2017; 8:14787. [PMID: 28317912 PMCID: PMC5364386 DOI: 10.1038/ncomms14787] [Citation(s) in RCA: 235] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 01/31/2017] [Indexed: 02/02/2023] Open
Abstract
Injury to the central nervous system (CNS) alters the molecular and cellular composition of neural tissue and leads to glial scarring, which inhibits the regrowth of damaged axons. Mammalian glial scars supposedly form a chemical and mechanical barrier to neuronal regeneration. While tremendous effort has been devoted to identifying molecular characteristics of the scar, very little is known about its mechanical properties. Here we characterize spatiotemporal changes of the elastic stiffness of the injured rat neocortex and spinal cord at 1.5 and three weeks post-injury using atomic force microscopy. In contrast to scars in other mammalian tissues, CNS tissue significantly softens after injury. Expression levels of glial intermediate filaments (GFAP, vimentin) and extracellular matrix components (laminin, collagen IV) correlate with tissue softening. As tissue stiffness is a regulator of neuronal growth, our results may help to understand why mammalian neurons do not regenerate after injury.
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Affiliation(s)
- Emad Moeendarbary
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK,Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave 56, Cambridge, Massachusetts 02139, USA,Department of Mechanical Engineering, University College London, London WC1E 7JE, UK,
| | - Isabell P. Weber
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Graham K. Sheridan
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK,School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ, UK
| | - David E. Koser
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Sara Soleman
- John van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge CB2 0PY, UK
| | - Barbara Haenzi
- John van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge CB2 0PY, UK
| | - Elizabeth J. Bradbury
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - James Fawcett
- John van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge CB2 0PY, UK
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK,
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19
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Bartus K, Galino J, James ND, Hernandez-Miranda LR, Dawes JM, Fricker FR, Garratt AN, McMahon SB, Ramer MS, Birchmeier C, Bennett DLH, Bradbury EJ. Neuregulin-1 controls an endogenous repair mechanism after spinal cord injury. Brain 2016; 139:1394-416. [PMID: 26993800 PMCID: PMC5477508 DOI: 10.1093/brain/aww039] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/24/2016] [Indexed: 12/16/2022] Open
Abstract
Spontaneous remyelination after spinal cord injury is mediated largely by Schwann cells
of unknown origin. Bartus et al. show that neuregulin-1 promotes
differentiation of spinal cord-resident precursor cells into PNS-like Schwann cells, which
remyelinate central axons and promote functional recovery. Targeting the neuregulin-1
system could enhance endogenous regenerative processes. Following traumatic spinal cord injury, acute demyelination of spinal axons is followed
by a period of spontaneous remyelination. However, this endogenous repair response is
suboptimal and may account for the persistently compromised function of surviving axons.
Spontaneous remyelination is largely mediated by Schwann cells, where demyelinated central
axons, particularly in the dorsal columns, become associated with peripheral myelin. The
molecular control, functional role and origin of these central remyelinating Schwann cells
is currently unknown. The growth factor neuregulin-1 (Nrg1, encoded by
NRG1) is a key signalling factor controlling myelination in the
peripheral nervous system, via signalling through ErbB tyrosine kinase receptors. Here we
examined whether Nrg1 is required for Schwann cell-mediated remyelination of central
dorsal column axons and whether Nrg1 ablation influences the degree of spontaneous
remyelination and functional recovery following spinal cord injury. In contused adult mice
with conditional ablation of Nrg1, we found an absence of Schwann cells within the spinal
cord and profound demyelination of dorsal column axons. There was no compensatory increase
in oligodendrocyte remyelination. Removal of peripheral input to the spinal cord and
proliferation studies demonstrated that the majority of remyelinating Schwann cells
originated within the injured spinal cord. We also examined the role of specific Nrg1
isoforms, using mutant mice in which only the immunoglobulin-containing isoforms of Nrg1
(types I and II) were conditionally ablated, leaving the type III Nrg1 intact. We found
that the immunoglobulin Nrg1 isoforms were dispensable for Schwann cell-mediated
remyelination of central axons after spinal cord injury. When functional effects were
examined, both global Nrg1 and immunoglobulin-specific Nrg1 mutants demonstrated reduced
spontaneous locomotor recovery compared to injured controls, although global Nrg1 mutants
were more impaired in tests requiring co-ordination, balance and proprioception.
Furthermore, electrophysiological assessments revealed severely impaired axonal conduction
in the dorsal columns of global Nrg1 mutants (where Schwann cell-mediated remyelination is
prevented), but not immunoglobulin-specific mutants (where Schwann cell-mediated
remyelination remains intact), providing robust evidence that the profound demyelinating
phenotype observed in the dorsal columns of Nrg1 mutant mice is related to conduction
failure. Our data provide novel mechanistic insight into endogenous regenerative processes
after spinal cord injury, demonstrating that Nrg1 signalling regulates central axon
remyelination and functional repair and drives the trans-differentiation of central
precursor cells into peripheral nervous system-like Schwann cells that remyelinate spinal
axons after injury. Manipulation of the Nrg1 system could therefore be exploited to
enhance spontaneous repair after spinal cord injury and other central nervous system
disorders with a demyelinating pathology.
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Affiliation(s)
- Katalin Bartus
- The Wolfson Centre for Age-Related Diseases, Regeneration Group, King's College London, Guy's Campus, London Bridge, London, UK
| | - Jorge Galino
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford, UK
| | - Nicholas D James
- The Wolfson Centre for Age-Related Diseases, Regeneration Group, King's College London, Guy's Campus, London Bridge, London, UK
| | | | - John M Dawes
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford, UK
| | - Florence R Fricker
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford, UK
| | - Alistair N Garratt
- Max Delbrück Center for Molecular Medicine, Berlin, Germany Charité Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany
| | - Stephen B McMahon
- The Wolfson Centre for Age-Related Diseases, Regeneration Group, King's College London, Guy's Campus, London Bridge, London, UK
| | - Matt S Ramer
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, Canada
| | | | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford, UK
| | - Elizabeth J Bradbury
- The Wolfson Centre for Age-Related Diseases, Regeneration Group, King's College London, Guy's Campus, London Bridge, London, UK
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20
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Offiah I, Didangelos A, Dawes J, Cartwright R, Khullar V, Bradbury EJ, O'Sullivan S, Williams D, Chessell IP, Pallas K, Graham G, O'Reilly BA, McMahon SB. The Expression of Inflammatory Mediators in Bladder Pain Syndrome. Eur Urol 2016; 70:283-90. [PMID: 26965559 PMCID: PMC4926725 DOI: 10.1016/j.eururo.2016.02.058] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 02/19/2016] [Indexed: 11/27/2022]
Abstract
Background Bladder pain syndrome (BPS) pathology is poorly understood. Treatment strategies are empirical, with limited efficacy, and affected patients have diminished quality of life. Objective We examined the hypothesis that inflammatory mediators within the bladder contribute to BPS pathology. Design, setting, and participants Fifteen women with BPS and 15 women with stress urinary incontinence without bladder pain were recruited from Cork University Maternity Hospital from October 2011 to October 2012. During cystoscopy, 5-mm bladder biopsies were taken and processed for gene expression analysis. The effect of the identified genes was tested in laboratory animals. Outcome measures and statistical analysis We studied the expression of 96 inflammation-related genes in diseased and healthy bladders. We measured the correlation between genes and patient clinical profiles using the Pearson correlation coefficient. Results and limitations Analysis revealed 15 differentially expressed genes, confirmed in a replication study. FGF7 and CCL21 correlated significantly with clinical outcomes. Intravesical CCL21 instillation in rats caused increased bladder excitability and increased c-fos activity in spinal cord neurons. CCL21 atypical receptor knockout mice showed significantly more c-fos upon bladder stimulation with CCL21 than wild-type littermates. There was no change in FGF7-treated animals. The variability in patient samples presented as the main limitation. We used principal component analysis to identify similarities within the patient group. Conclusions Our study identified two biologically relevant inflammatory mediators in BPS and demonstrated an increase in nociceptive signalling with CCL21. Manipulation of this ligand is a potential new therapeutic strategy for BPS. Patient summary We compared gene expression in bladder biopsies of patients with bladder pain syndrome (BPS) and controls without pain and identified two genes that were increased in BPS patients and correlated with clinical profiles. We tested the effect of these genes in laboratory animals, confirming their role in bladder pain. Manipulating these genes in BPS is a potential treatment strategy.
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Affiliation(s)
- Ifeoma Offiah
- Neurorestoration Group, Wolfson Centre for Age Related Diseases, King's College London, London, UK; Department of Urogynaecology, Cork University Maternity Hospital, University College Cork, Wilton, Co. Cork, Ireland.
| | - Athanasios Didangelos
- Neurorestoration Group, Wolfson Centre for Age Related Diseases, King's College London, London, UK
| | - John Dawes
- Neurorestoration Group, Wolfson Centre for Age Related Diseases, King's College London, London, UK
| | - Rufus Cartwright
- Department of Epidemiology and Biostatistics, Imperial College London, London, UK
| | - Vik Khullar
- Department of Epidemiology and Biostatistics, Imperial College London, London, UK
| | - Elizabeth J Bradbury
- Neurorestoration Group, Wolfson Centre for Age Related Diseases, King's College London, London, UK
| | - Suzanne O'Sullivan
- Department of Urogynaecology, Cork University Maternity Hospital, University College Cork, Wilton, Co. Cork, Ireland
| | | | | | - Kenny Pallas
- The Beatson Institute for Cancer Research, Glasgow, UK
| | - Gerry Graham
- The Beatson Institute for Cancer Research, Glasgow, UK
| | - Barry A O'Reilly
- Department of Urogynaecology, Cork University Maternity Hospital, University College Cork, Wilton, Co. Cork, Ireland
| | - Stephen B McMahon
- Neurorestoration Group, Wolfson Centre for Age Related Diseases, King's College London, London, UK
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21
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James ND, Shea J, Muir EM, Verhaagen J, Schneider BL, Bradbury EJ. Chondroitinase gene therapy improves upper limb function following cervical contusion injury. Exp Neurol 2015; 271:131-5. [PMID: 26044197 PMCID: PMC4590527 DOI: 10.1016/j.expneurol.2015.05.022] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/27/2015] [Indexed: 12/21/2022]
Abstract
Chondroitin sulphate proteoglycans (CSPGs) are known to be important contributors to the intensely inhibitory environment that prevents tissue repair and regeneration following spinal cord injury. The bacterial enzyme chondroitinase ABC (ChABC) degrades these inhibitory molecules and has repeatedly been shown to promote functional recovery in a number of spinal cord injury models. However, when used to treat more traumatic and clinically relevant spinal contusion injuries, findings with the ChABC enzyme have been inconsistent. We recently demonstrated that delivery of mammalian-compatible ChABC via gene therapy led to sustained and widespread digestion of CSPGs, resulting in significant functional repair of a moderate thoracic contusion injury in adult rats. Here we demonstrate that chondroitinase gene therapy significantly enhances upper limb function following cervical contusion injury, with improved forelimb ladder performance and grip strength as well as increased spinal conduction through the injury site and reduced lesion pathology. This is an important addition to our previous findings as improving upper limb function is a top priority for spinal injured patients. Additionally great importance is placed on replication in the spinal cord injury field. That chondroitinase gene therapy has now been shown to be efficacious in contusion models at either thoracic or cervical level is an important step in the further development of this promising therapeutic strategy towards the clinic.
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Affiliation(s)
- Nicholas D James
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Guy's Campus, London Bridge, London SE1 1UL, UK
| | - Jessie Shea
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Guy's Campus, London Bridge, London SE1 1UL, UK
| | - Elizabeth M Muir
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, 1105BA Amsterdam, The Netherlands
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Guy's Campus, London Bridge, London SE1 1UL, UK.
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Kwon BK, Streijger F, Hill CE, Anderson AJ, Bacon M, Beattie MS, Blesch A, Bradbury EJ, Brown A, Bresnahan JC, Case CC, Colburn RW, David S, Fawcett JW, Ferguson AR, Fischer I, Floyd CL, Gensel JC, Houle JD, Jakeman LB, Jeffery ND, Jones LAT, Kleitman N, Kocsis J, Lu P, Magnuson DSK, Marsala M, Moore SW, Mothe AJ, Oudega M, Plant GW, Rabchevsky AS, Schwab JM, Silver J, Steward O, Xu XM, Guest JD, Tetzlaff W. Large animal and primate models of spinal cord injury for the testing of novel therapies. Exp Neurol 2015; 269:154-68. [PMID: 25902036 DOI: 10.1016/j.expneurol.2015.04.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/08/2015] [Accepted: 04/13/2015] [Indexed: 12/28/2022]
Abstract
Large animal and primate models of spinal cord injury (SCI) are being increasingly utilized for the testing of novel therapies. While these represent intermediary animal species between rodents and humans and offer the opportunity to pose unique research questions prior to clinical trials, the role that such large animal and primate models should play in the translational pipeline is unclear. In this initiative we engaged members of the SCI research community in a questionnaire and round-table focus group discussion around the use of such models. Forty-one SCI researchers from academia, industry, and granting agencies were asked to complete a questionnaire about their opinion regarding the use of large animal and primate models in the context of testing novel therapeutics. The questions centered around how large animal and primate models of SCI would be best utilized in the spectrum of preclinical testing, and how much testing in rodent models was warranted before employing these models. Further questions were posed at a focus group meeting attended by the respondents. The group generally felt that large animal and primate models of SCI serve a potentially useful role in the translational pipeline for novel therapies, and that the rational use of these models would depend on the type of therapy and specific research question being addressed. While testing within these models should not be mandatory, the detection of beneficial effects using these models lends additional support for translating a therapy to humans. These models provides an opportunity to evaluate and refine surgical procedures prior to use in humans, and safety and bio-distribution in a spinal cord more similar in size and anatomy to that of humans. Our results reveal that while many feel that these models are valuable in the testing of novel therapies, important questions remain unanswered about how they should be used and how data derived from them should be interpreted.
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Affiliation(s)
- Brian K Kwon
- University of British Columbia, ICORD, Room 6196, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC V5Z 1 M9, Canada.
| | - Femke Streijger
- University of British Columbia, ICORD, Room 6196, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC V5Z 1 M9, Canada.
| | - Caitlin E Hill
- Burke Medical Research Institute/Weill Cornell Medical College, 785 Mamaroneck Ave., White Plains, NY 10605, USA.
| | | | - Mark Bacon
- International Spinal Research Trust, International Spinal Research Trust, Bramley Business Centre, Station Road, Bramley, Guildford, Surrey GU5 0AZ, UK.
| | - Michael S Beattie
- University of California at San Francisco, 1001 Potrero Ave., Bldg 1 Rm 101, San Francisco, CA 94110, USA.
| | - Armin Blesch
- Heidelberg University Hospital, Spinal Cord Injury Center, Germany.
| | - Elizabeth J Bradbury
- King's College London, The Wolfson Centre for Age-Related Diseases, Wolfson Wing, Hodgkin Building, Guy's Campus, London Bridge, London SE1 1UL, UK.
| | - Arthur Brown
- University of Western Ontario, Robarts Research Institute, University of Western Ontario, Department of Anatomy and Cell Biology, 1151 Richmond Street, North, N6A 5B7, Canada.
| | - Jacqueline C Bresnahan
- University of California at San Francisco, 1001 Potrero Ave., Bldg 1 Rm 101, San Francisco, CA 94110, USA.
| | - Casey C Case
- Asterias Biotherapeutics, 230 Constitution Drive, Menlo Park, CA 94025, USA.
| | - Raymond W Colburn
- Acorda Therapeutics, Acorda Therapeutics, Inc., 420 Saw Mill River Road, Ardsley, NY 10502, USA.
| | - Samuel David
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, 1650 Cedar Ave., Montreal, Quebec H3G 1A4, Canada.
| | - James W Fawcett
- University of Cambridge, John van Geest Centre for Brain Repair, Robinson Way, Cambridge CB2 0PY, UK.
| | - Adam R Ferguson
- University of California, San Francisco (UCSF), Brain and Spinal Injury Center (BASIC), Department of Neurological Surgery, USA.
| | - Itzhak Fischer
- Drexel University College of Medicine, Dept. of Neurobiology and Anatomy, 2900 Queen Lane, Philadelphia, PA 19129, USA.
| | - Candace L Floyd
- University of Alabama at Birmingham, 529C Spain Rehabilitation Center, 1717 6th Avenue South, Birmingham, AL 35249, USA.
| | - John C Gensel
- University of Kentucky, Spinal Cord and Brain Injury Research Center, B463 Biomedical & Biological Sciences Research Building (BBSRB), 741 S. Limestone, Lexington, KY 40536, USA.
| | - John D Houle
- Drexel University College of Medicine, Spinal Cord Research Center, Philadelphia, PA 19129, USA.
| | - Lyn B Jakeman
- National Institutes of Health/NINDS, 6001 Executive Blvd. North, Bethesda, MD 20852, USA.
| | - Nick D Jeffery
- Iowa State University, Lloyd Veterinary Medical Center, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
| | | | - Naomi Kleitman
- Craig H. Neilsen Foundation, 16830 Ventura Blvd. Suite 352, Encino, CA 91436, USA.
| | - Jeffery Kocsis
- Yale University and VA CT Healthcare System, Neuroscience Center (127A), VA CT Healthcare Center, 950 Campbell Ave., West Haven, CT 06516, USA.
| | - Paul Lu
- VA-San Diego Healthcare System, University of California at San Diego, BMF2, Room 2126, 9500 Gilman Dr., La Jolla, CA 92093-0626, USA.
| | - David S K Magnuson
- University of Louisville School of Medicine, 511 S. Floyd St., MDR Rm 616, USA.
| | - Martin Marsala
- University of California, San Diego, Department of Anesthesiology SCRM, Room 4009, 2880 Torrey Pines Scenic Dr., La Jolla, CA 92037, USA.
| | - Simon W Moore
- InVivo Therapeutics Corporation, One Kendall Square, Suite B14402, Cambridge, MA 02139, USA.
| | - Andrea J Mothe
- Toronto Western Research Institute, Krembil Discovery Tower, 60 Leonard Ave. , 7KD-406, Toronto ON M5T 2S8, Canada.
| | - Martin Oudega
- University of Miami Miller School of Medicine, LPLC, 1095 NW 14 Terrace, Miami, FL 33136, USA.
| | - Giles W Plant
- Stanford University, Lorry I. Lokey Stem Cell Research Building, Stanford University, 265 Campus Drive, Stanford, CA 94305, USA.
| | | | | | - Jerry Silver
- Case Western Reserve University, Dept. of Neurosciences, School of Medicine, 2109 Adelbert Rd., Cleveland, OH 44106, USA.
| | - Oswald Steward
- University of California Irvine, Reeve-Irvine Research Center, Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, Irvine, CA 92697, USA.
| | - Xiao-Ming Xu
- Indiana University School of Medicine, 320 W. 15th St., Indianapolis, IN 46202, USA.
| | | | - Wolfram Tetzlaff
- University of British Columbia, ICORD, Room 6196, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC V5Z 1 M9, Canada.
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Bradbury EJ, Ramer MS, Ramer LM. Sulfonylureas--a novel treatment to reduce tissue damage after acute spinal cord injury?--Authors' reply. Lancet Neurol 2015; 14:352-3. [PMID: 25792092 DOI: 10.1016/s1474-4422(15)70038-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Elizabeth J Bradbury
- Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London Bridge, London, UK.
| | - Matt S Ramer
- Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London Bridge, London, UK; International Collaboration On Repair Discoveries, Blusson Spinal Cord Centre, Vancouver General Hospital, Vancouver, BC, Canada; Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Leanne M Ramer
- Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London Bridge, London, UK; International Collaboration On Repair Discoveries, Blusson Spinal Cord Centre, Vancouver General Hospital, Vancouver, BC, Canada
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Abstract
Spinal cord injury is currently incurable and treatment is limited to minimising secondary complications and maximising residual function by rehabilitation. Improved understanding of the pathophysiology of spinal cord injury and the factors that prevent nerve and tissue repair has fuelled a move towards more ambitious experimental treatments aimed at promoting neuroprotection, axonal regeneration, and neuroplasticity. By necessity, these new options are more invasive. However, in view of recent advances in spinal cord injury research and demand from patients, clinicians, and the scientific community to push promising experimental treatments to the clinic, momentum and optimism exist for the translation of candidate experimental treatments to clinical spinal cord injury. The ability to rescue, reactivate, and rewire spinal systems to restore function after spinal cord injury might soon be within reach.
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Affiliation(s)
- Leanne M Ramer
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK; International Collaboration On Repair Discoveries, Blusson Spinal Cord Centre, Vancouver General Hospital, Vancouver, BC, Canada
| | - Matt S Ramer
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK; International Collaboration On Repair Discoveries, Blusson Spinal Cord Centre, Vancouver General Hospital, Vancouver, BC, Canada; Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK.
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Wilkinson SJ, Bradbury EJ, Thomson PC, Bedford MR, Cowieson AJ. Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. The effect of different dietary calcium and phosphorus concentrations and ratios on nutrient digestibility. Animal 2014; 8:1080-8. [PMID: 24840343 DOI: 10.1017/s1751731114001049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A total of 600 Ross 308-day-old male broiler chicks were used in a 28 day digestibility study to investigate the interaction between dietary calcium (Ca) and non-phytate phosphorus (nPP) on the digestibility of minerals and amino acids. Diets were formulated to be nutritionally adequate except for Ca and nPP. Fifteen mash diets based on corn and soya bean meal with varying concentrations of Ca (6.4 to 12.0 g/kg) and nPP (2.4 to 7.0 g/kg) were used. Diets were clustered around total densities of Ca and nPP of 12, 13.5 or 15.0 (g/kg) and within each density, a range of five Ca : nPP ratios (1.14 : 1, 1.5 : 1, 2.0 : 1, 2.75 : 1 and 4.0 : 1) were fed. Birds had free access to feed and water throughout the study. At day 28, birds were euthanised for the determination of apparent ileal mineral and amino acid digestibility. Data were modelled in R version 2.15 using a linear mixed-effects model and interrogation of the data was performed by fitting a low order polynomial function. At high Ca concentrations, increasing nPP led to an increase in the apparent digestibility of minerals. Apparent ileal digestibility of phosphorus (P) was enhanced with increasing dietary nPP up to 5.5 g/kg beyond which no improvements were found. Maximal Ca digestibility was found in diets with >8.0 g/kg Ca with concomitant low concentrations of nPP. Diets with a broader Ca : nPP ratio improved the digestibility of Ca but were deleterious to the digestibility of P. In this study, apparent digestibility of amino acids was broadly unaffected by dietary Ca and nPP concentrations. However, interactions between Ca and nPP were observed for the digestibility of glutamine, tyrosine and methionine (all P<0.001). Nitrogen digestibility showed discrete optima around 10.0 and 5.0 g/kg nPP and Na digestibility was maximised around 8 to 9.0 g/kg Ca and 4.5 to 5.4 g/kg nPP. These data show that the ratio of Ca : nPP is more influential to mineral digestibility than the absolute dietary concentration of each macro mineral.
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Affiliation(s)
- S J Wilkinson
- 1Poultry Research Foundation,The University of Sydney, Faculty of Veterinary Science,425 Werombi Road,Camden,NSW 2570,Australia
| | - E J Bradbury
- 1Poultry Research Foundation,The University of Sydney, Faculty of Veterinary Science,425 Werombi Road,Camden,NSW 2570,Australia
| | - P C Thomson
- 2Faculty of Veterinary Science,The University of Sydney,Camden,NSW 2570,Australia
| | - M R Bedford
- 3AB Vista Feed Ingredients,Marlborough,Wiltshire,SN84AN,UK
| | - A J Cowieson
- 1Poultry Research Foundation,The University of Sydney, Faculty of Veterinary Science,425 Werombi Road,Camden,NSW 2570,Australia
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26
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Bosch KD, Bradbury EJ, Verhaagen J, Fawcett JW, McMahon SB. Chondroitinase ABC promotes plasticity of spinal reflexes following peripheral nerve injury. Exp Neurol 2012; 238:64-78. [DOI: 10.1016/j.expneurol.2012.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/27/2012] [Accepted: 08/01/2012] [Indexed: 10/28/2022]
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27
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Starkey ML, Bartus K, Barritt AW, Bradbury EJ. Chondroitinase ABC promotes compensatory sprouting of the intact corticospinal tract and recovery of forelimb function following unilateral pyramidotomy in adult mice. Eur J Neurosci 2012; 36:3665-78. [PMID: 23061434 DOI: 10.1111/ejn.12017] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 08/26/2012] [Accepted: 09/12/2012] [Indexed: 12/11/2022]
Abstract
Chondroitin sulphate proteoglycans (CSPGs) are extracellular matrix molecules whose inhibitory activity is attenuated by the enzyme chondroitinase ABC (ChABC). Here we assess whether CSPG degradation can promote compensatory sprouting of the intact corticospinal tract (CST) following unilateral injury and restore function to the denervated forelimb. Adult C57BL/6 mice underwent unilateral pyramidotomy and treatment with either ChABC or a vehicle control. Significant impairments in forepaw symmetry were observed following pyramidotomy, with injured mice preferentially using their intact paw during spontaneous vertical exploration of a cylinder. No recovery on this task was observed in vehicle-treated mice. However, ChABC-treated mice showed a marked recovery of function, with forelimb symmetry fully restored by 5 weeks post-injury. Functional recovery was associated with robust sprouting of the uninjured CST, with numerous axons observed crossing the midline in the brainstem and spinal cord and terminating in denervated grey matter. CST fibres in the denervated side of the spinal cord following ChABC treatment were closely associated with the synaptic marker vGlut1. Immunohistochemical assessment of chondroitin-4-sulphate revealed that CSPGs were heavily digested around lamina X, alongside midline crossing axons and in grey matter regions where sprouting axons and reduced peri-neuronal net staining was observed. Thus, we demonstrate that CSPG degradation promotes midline crossing and reinnervation of denervated target regions by intact CST axons and leads to restored function in the denervated forepaw. Enhancing compensatory sprouting using ChABC provides a route to restore function that could be applied to disorders such as spinal cord injury and stroke.
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Affiliation(s)
- Michelle L Starkey
- Regeneration Group, King's College London, Wolfson Centre for Age-Related Diseases, Hodgkin Building, Guy's Campus, London Bridge, London, SE1 IUL, UK
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28
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29
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Abstract
Spinal cord injury (SCI) has multiple consequences, ranging from molecular imbalances to glial scar formation to functional impairments. It is logical to think that a combination of single treatments implemented in the right order and at the right time will be required to repair the spinal cord. However, the single treatments that compose the combination therapy will need to be chosen with caution as many have multiple outcomes that may or may not be synergistic. Single treatments may also elicit unwanted side-effects and/or effects that would decrease the repair potential of other components and/or the entire combination therapy. In this chapter a number of single treatments are discussed with respect to their multiplicity of action. These include strategies to boost growth and survival (such as neurotrophins and cyclic AMP) and strategies to reduce inhibitory factors (such as antimyelin-associated growth inhibitors and digestion of glial scar-associated inhibitors). We also present an overview of combination therapies that have successfully or unsuccessfully been tested in the laboratory using animal models. To effectively design a combination therapy a number of considerations need to be made such as the nature and timing of the treatments and the method for delivery. This chapter discusses these issues as well as considerations related to chronic SCI and the logistics of bringing combination therapies to the clinic.
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Affiliation(s)
- M Oudega
- Departments of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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30
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Bartus K, James ND, Bosch KD, Bradbury EJ. Chondroitin sulphate proteoglycans: key modulators of spinal cord and brain plasticity. Exp Neurol 2011; 235:5-17. [PMID: 21871887 DOI: 10.1016/j.expneurol.2011.08.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 07/15/2011] [Accepted: 08/08/2011] [Indexed: 01/08/2023]
Abstract
Chondroitin sulphate proteoglycans (CSPGs) are a family of inhibitory extracellular matrix molecules that are highly expressed during development, where they are involved in processes of pathfinding and guidance. CSPGs are present at lower levels in the mature CNS, but are highly concentrated in perineuronal nets where they play an important role in maintaining stability and restricting plasticity. Whilst important for maintaining stable connections, this can have an adverse effect following insult to the CNS, restricting the capacity for repair, where enhanced synapse formation leading to new connections could be functionally beneficial. CSPGs are also highly expressed at CNS injury sites, where they can restrict anatomical plasticity by inhibiting sprouting and reorganisation, curbing the extent to which spared systems may compensate for the loss function of injured pathways. Modification of CSPGs, usually involving enzymatic degradation of glycosaminoglycan chains from the CSPG molecule, has received much attention as a potential strategy for promoting repair following spinal cord and brain injury. Pre-clinical studies in animal models have demonstrated a number of reparative effects of CSPG modification, which are often associated with functional recovery. Here we discuss the potential of CSPG modification to stimulate restorative plasticity after injury, reviewing evidence from studies in the brain, the spinal cord and the periphery.
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Affiliation(s)
- K Bartus
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London Bridge, SE1 1UL, UK.
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31
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Carter LM, McMahon SB, Bradbury EJ. Delayed treatment with chondroitinase ABC reverses chronic atrophy of rubrospinal neurons following spinal cord injury. Exp Neurol 2011; 228:149-56. [PMID: 21215745 DOI: 10.1016/j.expneurol.2010.12.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 12/04/2010] [Accepted: 12/24/2010] [Indexed: 01/05/2023]
Abstract
Degradation of extracellular matrix chondroitin sulphate proteoglycans (CSPGs) using Chondroitinase ABC (ChABC) is a promising strategy for the treatment of spinal cord injury, with potent effects on promoting functional recovery and anatomical repair in spinal injured animals. We have previously demonstrated that ChABC treatment prevents atrophy of corticospinal projection neurons following spinal injury in adult YFP-H mice. Here, we investigate whether ChABC-mediated repair of the cell body extends to rubrospinal projection neurons (RSNs), whether neuroprotective effects can be sustained long-term and importantly, whether delayed treatment with ChABC can reverse chronic atrophy. Adult YFP-H mice underwent unilateral rubrospinal tract transection and were treated with ChABC or a control enzyme, delivered either acutely post-injury or after a one month delay. Eight weeks following injury and control treatment, RSNs in the injured red nucleus, identified by YFP label and NeuN immunoreactivity, showed severe atrophy, with ~40% loss of mean cell area compared to uninjured neurons in the contralateral red nucleus. Both acute and delayed treatment with ChABC promoted a significant rescue of injured RSNs, restoring cell area to ~80% and ~70%, respectively, of that in uninjured neurons. Thus, we demonstrate for the first time that CSPG degradation in the injured spinal cord not only promotes sustained rescue of cell atrophy when delivered acutely but can also reverse chronic atrophy in descending projection neurons. Thus, modulation of the extracellular matrix can mediate neuroprotective effects both early and late after spinal cord injury.
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Affiliation(s)
- Lucy M Carter
- King's College London, Neurorestoration Group, Wolfson Centre for Age Related Diseases, Wolfson Wing, Hodgkin Building, Guy's Campus, London Bridge, London SE1 1UL, UK.
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Starkey ML, Davies M, Yip PK, Carter LM, Wong DJN, McMahon SB, Bradbury EJ. Expression of the regeneration-associated protein SPRR1A in primary sensory neurons and spinal cord of the adult mouse following peripheral and central injury. J Comp Neurol 2009; 513:51-68. [PMID: 19107756 DOI: 10.1002/cne.21944] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Small proline-rich repeat protein 1A (SPRR1A) is expressed in dorsal root ganglion (DRG) neurons following peripheral nerve injury but it is not known whether SPRR1A is differentially expressed following injury to peripheral versus central DRG projections and a detailed characterization of expression in sensory neuron subpopulations and spinal cord has not been performed. Here we use immunocytochemical techniques to characterize SPRR1A expression following sciatic nerve, dorsal root, and dorsal column injury in adult mice. SPRR1A was not detected in naïve spinal cord, DRG, or peripheral nerves and there was minimal expression following injury to the centrally projecting branches of DRG neurons. However, following peripheral (sciatic) nerve injury, intense SPRR1A immunoreactivity was observed in the dorsal horn and motoneurons of the spinal cord, in L4/5 DRG neurons, and in the injured nerve. A time-course study comparing expression following sciatic nerve crush and transection revealed maximum SPRR1A levels at day 7 in both models. However, while SPRR1A was downregulated to baseline by 30 days postlesion following crush injury, it remained elevated 30 days after transection. Cell-size and double-labeling studies revealed that SPRR1A was expressed by DRG cells of all sizes and colocalized with classical markers of DRG subpopulations and their primary afferent terminals. High coexpression of SPRR1A with activating transcription factor-3 and growth-associated protein-43 was observed, indicating that it is expressed by injured and regenerating neurons. This study supports the hypothesis that SPRR1A is a regeneration-associated gene and that SPRR1A provides a valuable marker to assess the regenerative potential of injured neurons.
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Affiliation(s)
- Michelle L Starkey
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, Wolfson Wing, King's College London, London Bridge, London.
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33
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Webber DJ, Yip P, Bradbury EJ, Minger SL, McMahon SB. Neural progenitors promote axon growth in vitro and ex vivo but not following injury. J Stem Cells 2009; 4:1-16. [PMID: 20498687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Following an injury to the dorsal roots primary sensory afferents fail to regenerate past the hostile dorsal root entry zone (DREZ), the interface between the peripheral and central nervous system. Neural progenitor cells have previously been utilised as a cellular replacement therapy in a variety of CNS injury models. Here we show for the first time that NPCs are capable of promoting neurite outgrowth from adult sensory neurons in vitro and ex vivo cryo-cultures. The effectiveness of NPCs as a potential means of promoting regeneration of primary afferents across the DREZ was assessed following rhizotomy at the cervical level in the adult rat. Adult rats were subjected to rhizotomy of the dorsal roots between C(5)-T(1) which were then reanastamosed. In conjunction with the rhizotomy NPCs were delivered at the DREZ. NPCs survived transplantation and were observed to differentiate predominantly into glia. Regeneration of the dorsal root fibers was assessed with immunhistochemical analysis of the large and small diameter peptidergic and non-peptidergic afferents. Although afferents appeared near to the DREZ there was little regeneration beyond the DREZ. Furthermore, no significant improvement was observed in behavioural tasks.
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Affiliation(s)
- Daniel J Webber
- Brain Repair Centre, University of Cambridge, Forvie Site, Cambridge, CB2 2PY
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Marchand F, Tsantoulas C, Singh D, Grist J, Clark AK, Bradbury EJ, McMahon SB. Effects of Etanercept and Minocycline in a rat model of spinal cord injury. Eur J Pain 2008; 13:673-81. [PMID: 18849175 DOI: 10.1016/j.ejpain.2008.08.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/15/2008] [Accepted: 08/10/2008] [Indexed: 10/21/2022]
Abstract
Loss of function is usually considered the major consequence of spinal cord injury (SCI). However, pain severely compromises the quality of life in nearly 70% of SCI patients. The principal aim of this study was to assess the contribution of Tumor necrosis factor alpha (TNF-alpha) to SCI pain. TNF-alpha blockers have already been successfully used to treat inflammatory disorders but there are few studies on its effect on neuropathic pain, especially following SCI. Following T13 spinal cord hemisection, we examined the effects on mechanical allodynia and microglial activation of immediate and delayed chronic intrathecal treatment with etanercept, a fusion protein blocker of TNF-alpha. Immediate treatment (starting at the time of injury) with etanercept resulted in markedly reduced mechanical allodynia 1, 2, 3 and 4 weeks after SCI. Delayed treatment had no effect. Immediate etanercept treatment also reduced spinal microglial activation assessed by OX-42 immunostaining, a putative marker of activated microglia. To assess whether the effects of etanercept were mediated via decreased microglial activation, we examined the effects of the microglial inhibitor, minocycline which significantly reduced the development of pain behaviours at 1 and 2 weeks after SCI compared to saline treatment. Minocycline also significantly reduced microglial OX-42 expression. Furthermore, minocycline decreased the expression of noxious-stimulation-induced c-Fos, suggesting an effect on evoked neuronal activity. This study demonstrates that TNF-alpha plays an important role in the establishment of neuropathic pain following SCI, seemingly dependent on microglial activation. Pharmacological targeting of TNF-alpha may offer therapeutic opportunities for treating SCI pain.
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Affiliation(s)
- Fabien Marchand
- Neurorestoration Group, King's College London, Wolfson Wing, Wolfson Centre for Age Related Diseases, Hodgkin Building, Guy's Campus, London SE1 1UL, United Kingdom
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35
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García-Alías G, Lin R, Akrimi SF, Story D, Bradbury EJ, Fawcett JW. Therapeutic time window for the application of chondroitinase ABC after spinal cord injury. Exp Neurol 2007; 210:331-8. [PMID: 18158149 DOI: 10.1016/j.expneurol.2007.11.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 11/08/2007] [Accepted: 11/08/2007] [Indexed: 11/17/2022]
Abstract
Rats with a crush in the dorsal funiculi of the C4 segment of the spinal cord were treated with chondroitinase ABC delivered to the lateral ventricle, receiving 6 intraventricular injections on alternate days. In order to investigate the time window of efficacy of chondroitinase, treatment was begun at the time of injury or after a 2, 4 or 7 days delay. Behavioural testing over 6 weeks showed that acutely treated animals showed improved skilled forelimb reaching compared to penicillinase controls. Forelimb contact placing recovered in treated animals but not controls, and gait analysis showed recovery towards normal forelimb stride length in treated animals but not controls. Chondroitinase-treated animals showed greater axon regeneration than controls. The treatment effect on contact placing, stride length and axon regeneration was not dependent on the timing of the start of treatment, but in skilled paw reaching acutely treated animals recovered better function. The area of chondroitinase ABC digestion visualized by stub antibody staining included widespread digestion around the lateral ventricles and partial digestion of cervical spinal cord white matter, but not grey matter.
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Affiliation(s)
- Guillermo García-Alías
- Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Cambridge CB2 0PY, UK
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36
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Webber DJ, Bradbury EJ, McMahon SB, Minger SL. Transplanted neural progenitor cells survive and differentiate but achieve limited functional recovery in the lesioned adult rat spinal cord. Regen Med 2007; 2:929-45. [DOI: 10.2217/17460751.2.6.929] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Endogenous repair after injury in the adult CNS is limited by a number of factors including cellular loss, inflammation, cavitation and glial scarring. Spinal cord neural progenitor cells (SCNPCs) may provide a valuable cellular source for promoting repair following spinal cord injury. SCNPCs are multipotent, can be expanded in vitro, have the capacity to differentiate into CNS cell lineages and are capable of long-term survival following transplantation. Aims & Method: To determine the extent to which SCNPCs may contribute to spinal cord repair SCNPCs isolated from rat fetal spinal cord were expanded ex vivo and transplanted into the adult rat spinal cord after a dorsal column crush lesion. Results: The survival and distribution of transplanted cells were examined at 24 h, 1, 2 and 6 weeks after injury. Transplanted cells were identified at all time points, located mainly at the lesion perimeter, indicating good post-transplant cell survival. Furthermore, SCNPCs maintained their ability to differentiate in vivo, with approximately 40% differentiating into cells with a glial morphology, whilst 8% displayed a neural morphology. Transplanted animals were also assessed on a number of behavioral tasks measuring sensorimotor and proprioceptive function to determine the extent to which SCNPC transplants might attenuate lesion-induced functional deficits. SCNPCs failed to promote significant functional recovery, with a small improvement observed in only one of the four tasks employed, primarily related to improvements in sensory function. Tracing of the corticospinal tract and ascending dorsal column pathway revealed no regeneration of the axons beyond the lesion site. Conclusions: These data indicate that, although transplanted SCNPCs show good survival in the spinal cord injury environment, combination with other treatment strategies is likely to be required for these cells to fully exert their therapeutic potential.
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Affiliation(s)
- Daniel J Webber
- University of Cambridge, Centre for Brain Repair, Forvie Site, Robinson Way, Cambridge, CB2 2PY, UK
- King’s College London, Neurorestoration Group, Wolfson Centre for Age Related Disease, Guy’s Campus, London, SE1 1UL, UK
- King’s College London, Stem Cell Biology Laboratory, Wolfson Centre, Guy’s Campus, London, SE1 1UL, UK
| | - Elizabeth J Bradbury
- King’s College London, Neurorestoration Group, Wolfson Centre for Age Related Disease, Guy’s Campus, London, SE1 1UL, UK
| | - Stephen B McMahon
- King’s College London, Neurorestoration Group, Wolfson Centre for Age Related Disease, Guy’s Campus, London, SE1 1UL, UK
| | - Stephen L Minger
- King’s College London, Stem Cell Biology Laboratory, Wolfson Centre, Guy’s Campus, London, SE1 1UL, UK
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37
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Eickholt BJ, Ahmed AI, Davies M, Papakonstanti EA, Pearce W, Starkey ML, Bilancio A, Need AC, Smith AJH, Hall SM, Hamers FP, Giese KP, Bradbury EJ, Vanhaesebroeck B. Control of axonal growth and regeneration of sensory neurons by the p110delta PI 3-kinase. PLoS One 2007; 2:e869. [PMID: 17846664 PMCID: PMC1959241 DOI: 10.1371/journal.pone.0000869] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 08/16/2007] [Indexed: 12/13/2022] Open
Abstract
The expression and function of the 8 distinct catalytic isoforms of PI 3-kinase (PI3K) in the nervous system are unknown. Whereas most PI3Ks have a broad tissue distribution, the tyrosine kinase-linked p110δ isoform has previously been shown to be enriched in leukocytes. Here we report that p110δ is also highly expressed in the nervous system. Inactivation of p110δ in mice did not affect gross neuronal development but led to an increased vulnerability of dorsal root ganglia neurons to exhibit growth cone collapse and decreases in axonal extension. Loss of p110δ activity also dampened axonal regeneration following peripheral nerve injury in adult mice and impaired functional recovery of locomotion. p110δ inactivation resulted in reduced neuronal signaling through the Akt protein kinase, and increased activity of the small GTPase RhoA. Pharmacological inhibition of ROCK, a downstream effector of RhoA, restored axonal extension defects in neurons with inactive p110δ, suggesting a key role of RhoA in p110δ signaling in neurons. Our data identify p110δ as an important signaling component for efficient axonal elongation in the developing and regenerating nervous system.
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Affiliation(s)
- Britta J Eickholt
- Medical Research Council Centre for Developmental Neurobiology, King's College London, London, United Kingdom.
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38
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Barritt AW, Davies M, Marchand F, Hartley R, Grist J, Yip P, McMahon SB, Bradbury EJ. Chondroitinase ABC promotes sprouting of intact and injured spinal systems after spinal cord injury. J Neurosci 2006; 26:10856-67. [PMID: 17050723 PMCID: PMC3339436 DOI: 10.1523/jneurosci.2980-06.2006] [Citation(s) in RCA: 331] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chondroitin sulfate proteoglycans (CSPGs) are inhibitory extracellular matrix molecules that are upregulated after CNS injury. Degradation of CSPGs using the enzyme chondroitinase ABC (ChABC) can promote functional recovery after spinal cord injury. However, the mechanisms underlying this recovery are not clear. Here we investigated the effects of ChABC treatment on promoting plasticity within the spinal cord. We found robust sprouting of both injured (corticospinal) and intact (serotonergic) descending projections as well as uninjured primary afferents after a cervical dorsal column injury and ChABC treatment. Sprouting fibers were observed in aberrant locations in degenerating white matter proximal to the injury in regions where CSPGs had been degraded. Corticospinal and serotonergic sprouting fibers were also observed in spinal gray matter at and below the level of the lesion, indicating increased innervation in the terminal regions of descending projections important for locomotion. Spinal-injured animals treated with a vehicle solution showed no significant sprouting. Interestingly, ChABC treatment in uninjured animals did not induce sprouting in any system. Thus, both denervation and CSPG degradation were required to promote sprouting within the spinal cord. We also examined potential detrimental effects of ChABC-induced plasticity. However, although primary afferent sprouting was observed after lumbar dorsal column lesions and ChABC treatment, there was no increased connectivity of nociceptive neurons or development of mechanical allodynia or thermal hyperalgesia. Thus, CSPG digestion promotes robust sprouting of spinal projections in degenerating and denervated areas of the spinal cord; compensatory sprouting of descending systems could be a key mechanism underlying functional recovery.
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Affiliation(s)
- A W Barritt
- Neurorestoration Group, Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, United Kingdom
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39
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Yip PK, Wong LF, Pattinson D, Battaglia A, Grist J, Bradbury EJ, Maden M, McMahon SB, Mazarakis ND. Lentiviral vector expressing retinoic acid receptor beta2 promotes recovery of function after corticospinal tract injury in the adult rat spinal cord. Hum Mol Genet 2006; 15:3107-18. [PMID: 16984961 DOI: 10.1093/hmg/ddl251] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spinal cord injury often results in permanent and devastating neurological deficits and disability. This is due to the limited regenerative capacity of neurones in the central nervous system (CNS). We recently demonstrated that a transcription factor retinoic acid receptor beta2 (RARbeta2) promoted axonal regeneration in adult sensory neurones located peripherally. However, it is not known if RARbeta2 can promote axonal regeneration in cortical neurones of the CNS. Here, we demonstrate that delivery of RARbeta2 via a lentiviral vector to adult dissociated cortical neurones significantly enhances neurite outgrowth on adult cortical cryosections, which normally provide an unfavourable substrate for growth. We also show that lentiviral-mediated transduction of corticospinal neurones resulted in robust transgene expression in layer V corticospinal neurones and their axonal projections in the corticospinal tract (CST) of the spinal cord. Expression of RARbeta2 in these neurones enhanced regeneration of the descending CST fibres after injury to these axons in the mid-cervical spinal cord. Furthermore, we observed functional recovery in sensory and locomotor behavioural tests in RARbeta2-treated animals. These results suggest that a direct and selective delivery of RARbeta2 to the corticospinal neurones promotes long-distance functional regeneration of axons in the spinal cord and may thus offer new therapeutic gene strategy for the treatment of human spinal cord injuries.
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Affiliation(s)
- Ping K Yip
- Neurorestoration Group, Wolfson CARD, 2 MRC Centre for Developmental Biology, King's College London, Guy's Campus, London Bridge, London SE1 1UL, UK
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40
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Abstract
There are now numerous preclinical reports of various experimental treatments promoting some functional recovery after spinal cord injury. Surprisingly, perhaps, the mechanisms that underlie recovery have rarely been definitively established. Here, we critically evaluate the evidence that regeneration of damaged pathways or compensatory collateral sprouting can promote recovery. We also discuss several more speculative mechanisms that might putatively explain or confound some of the reported outcomes of experimental interventions.
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Affiliation(s)
- Elizabeth J Bradbury
- Neurorestoration Group, Wolfson Wing, Hodgkin Building, Guy's Campus, King's College London, London Bridge, London SE1 1UL, UK
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41
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Clark AK, Gentry C, Bradbury EJ, McMahon SB, Malcangio M. Role of spinal microglia in rat models of peripheral nerve injury and inflammation. Eur J Pain 2006; 11:223-30. [PMID: 16545974 DOI: 10.1016/j.ejpain.2006.02.003] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 01/19/2006] [Accepted: 02/06/2006] [Indexed: 11/25/2022]
Abstract
Mounting evidence supports the hypothesis that spinal microglia modulate the development and maintenance of some chronic pain states. Here we examined the role of spinal microglia following both peripheral inflammatory insult and peripheral nerve injury. We observed significant ipsilateral dorsal horn microglia activation 2 weeks after injury and bilateral activation 50 days following nerve injury as well as 24 h following intraplantar zymosan but not intraplantar complete Freund's adjuvant (CFA). Ipsilateral but not contralateral microglia activation was associated with hind paw mechanical hyperalgesia. Spinal injection of the glial metabolic inactivator fluorocitrate attenuated ipsilateral hyperalgesia and bilateral spinal microglia activation after peripheral nerve injury. Intrathecal fluorocitrate reversed hyperalgesia after intraplantar zymosan and produced no reversal of CFA-induced hyperalgesia. These data suggest a role for spinal glia in the persistence of mechanical hyperalgesia following peripheral nerve injury. However, activation of spinal microglia contralaterally did not correlate to nociception. Furthermore, it would appear that the time course of microglia activation and their contribution to inflammatory pain is dependent on the inflammatory stimulus administered.
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Affiliation(s)
- Anna K Clark
- Neurorestoration, Wolfson Centre for Age Related Diseases, King's College London, Wolfson Wing, Hodgkin Building, Guys Campus, London SE1 1UL, UK
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42
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Moreno-Flores MT, Bradbury EJ, Martín-Bermejo MJ, Agudo M, Lim F, Pastrana E, Avila J, Díaz-Nido J, McMahon SB, Wandosell F. A clonal cell line from immortalized olfactory ensheathing glia promotes functional recovery in the injured spinal cord. Mol Ther 2006; 13:598-608. [PMID: 16427362 DOI: 10.1016/j.ymthe.2005.11.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 10/06/2005] [Accepted: 11/02/2005] [Indexed: 11/24/2022] Open
Abstract
Immortalized cell lines of olfactory ensheathing glia (OEG) that maintain the proregenerative properties of primary cultures provide an unlimited source of OEG for both basic and applied studies. Indeed, one specific immortalized rat OEG clonal line (TEG3) proved to be as good as primary OEG in promoting neuritogenesis and axon regeneration in culture models. Thus, we examined the capacity of TEG3 to promote axonal repair in an animal model of spinal cord injury, dorsal column crush. TEG3 cells can acquire astrocyte-like or Schwann cell-like morphology depending on the conditions under which they are cultured. In the injured spinal cord, prelabeled TEG3 survived for at least 10 weeks after grafting and they integrated into the spinal cord, adopting Schwann cell-like, astrocyte-like, or intermediate morphologies. In TEG3-transplanted animals, sensory projection axons grow into the lesion site and there was robust sprouting/axonal growth of the corticospinal tract, both into and beyond the lesion site, after crushing of the spinal cord-dorsal columns. TEG3-transplanted animals also recovered sensory and motor function in tape removal and beam walking behavioral tests. These data indicate that certain immortalized cell lines derived from a single cell can maintain the regenerative properties of primary OEG.
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Affiliation(s)
- M Teresa Moreno-Flores
- Centro de Biología Molecular "Severo Ochoa," Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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43
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Starkey ML, Barritt AW, Yip PK, Davies M, Hamers FPT, McMahon SB, Bradbury EJ. Assessing behavioural function following a pyramidotomy lesion of the corticospinal tract in adult mice. Exp Neurol 2005; 195:524-39. [PMID: 16051217 DOI: 10.1016/j.expneurol.2005.06.017] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 05/27/2005] [Accepted: 06/27/2005] [Indexed: 11/25/2022]
Abstract
We have developed a pyramidotomy model in mice to lesion the corticospinal tract at the level of the brainstem pyramidal tract, and evaluated the resultant impairments in motor function in a series of behavioural tests. Adult C57BL/6 mice received a unilateral pyramidotomy and a control group of mice underwent sham surgery. We studied the effects of this lesion on forepaw function using five behavioural paradigms, some of which have been widely used in rat studies but have not been fully explored in mice. The tests used were: a rearing test, which assesses forepaw use for weight support during spontaneous vertical exploration of a cylinder; a grid walking test, which assesses the ability to accurately place the forepaws during exploration of an elevated grid; a tape-removal test, which measures both sensory and motor function of the forepaw; a CatWalk automated gait analysis, which provides a number of quantitative measures including stride length and stride width during locomotion; and a staircase reaching task, which assesses skilled independent forepaw use. All tests revealed lesion effects on forepaw function with the tape removal, grid walking, rearing and CatWalk tests demonstrating robust effects throughout the testing period. The development of a pyramidotomy lesion model in mice, together with behavioural tests which can reliably measure functional impairments, will provide a valuable tool for assessing therapeutic strategies to promote regeneration and plasticity.
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Affiliation(s)
- Michelle L Starkey
- Neurorestoration Group, CARD Wolfson Wing, Hodgkin Building, King's College London, Guy's Campus, London Bridge, London SE1 IUL, UK
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44
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Agudo M, Robinson M, Cafferty W, Bradbury EJ, Kilkenny C, Hunt SP, McMahon SB. Regulation of neuropilin 1 by spinal cord injury in adult rats. Mol Cell Neurosci 2005; 28:475-84. [PMID: 15737738 DOI: 10.1016/j.mcn.2004.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Revised: 10/05/2004] [Accepted: 10/19/2004] [Indexed: 11/16/2022] Open
Abstract
Using RT-PCR, in situ hybridization, Western blotting, and immunofluorescence, we have analyzed the expression of neuropilin 1 (Np1) in two models of spinal cord injury (spinal cord hemisection and dorsal column crush) and following dorsal root rhizotomy in adult rats. Our results show that Np1 RNA and protein are up-regulated in the spinal cord after all these lesions but remain unaltered in the adjacent dorsal root ganglia. In control animals, Np1 levels in the spinal cord are low and appear to be localized mainly in blood vessels, motoneurons, and in the superficial layers of the dorsal horn. After DCC and rhizotomy, Np1 is expressed de novo around the injury and in the deafferentated dorsal horn, respectively, mainly by OX42-positive microglial cells. Both lesions affect the sensory projections, and interestingly a consistent increase of Np1 signal is additionally seen in the dorsal horn where these projections terminate. Unexpectedly, this increase is bilateral after unilateral rhizotomy.
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Affiliation(s)
- Marta Agudo
- Neuro Restoration CARD, Wolfson Centre Guy's Campus, King's College London, London Bridge, London SE1 1UL, UK.
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45
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Cronin JN, Bradbury EJ, Lidierth M. Laminar distribution of GABAA- and glycine-receptor mediated tonic inhibition in the dorsal horn of the rat lumbar spinal cord: effects of picrotoxin and strychnine on expression of Fos-like immunoreactivity. Pain 2004; 112:156-63. [PMID: 15494196 DOI: 10.1016/j.pain.2004.08.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2004] [Revised: 07/14/2004] [Accepted: 08/03/2004] [Indexed: 10/26/2022]
Abstract
Inhibitory mechanisms are essential in suppressing the development of allodynia and hyperalgesia in the normal animal and there is evidence that loss of inhibition can lead to the development of neuropathic pain. We used Fos expression to map the distribution of tonically inhibited cells in the healthy rat lumbar spinal cord. In a control group, Fos-like immunoreactive (Fos-LI) cells were rare, averaging 7.5+/-2.2 cells (mean+/-SEM; N=13 sections) per 20 microm thick section of dorsal horn. This rose to 103+/-11 (mean+/-SEM; N=20) in picrotoxin-treated rats and to 88+/-11 (mean+/-SEM; N=18) in strychnine-treated rats. These changes were significant (ANOVA; P<0.001). There were marked regional variations in the distribution of Fos-LI cells between picrotoxin- and strychnine-treated animals. Picrotoxin induced a significant increase in the number of Fos-LI cells throughout the dorsal horn (lamina I-VI) while strychnine significantly elevated Fos-like immunoreactivity only in deep laminae (III-VI). For both picrotoxin and strychnine, the increase in Fos-like immunoreactivity peaked in lamina V (at 3579+/-319 and 3649+/-375% of control, respectively; mean+/-SEM) but for picrotoxin an additional peak was observed in the outer part of lamina II (1959+/-196%). Intrathecal administration of both GABAA and glycine receptor antagonists has been shown elsewhere to induce tactile allodynia. The present data suggest that this allodynia could arise due to blockade of tonic GABAA and glycine-receptor mediated inhibition in the deep dorsal horn. GABAA antagonists also induce hypersensitivity to noxious inputs. The blockade of tonic inhibition in the superficial dorsal horn shown here may underlie this hyperalgesia.
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Affiliation(s)
- John N Cronin
- Department of Physiology, Hodgkin Building, King's College London, London SE1 1UL, UK
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46
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Averill S, Michael GJ, Shortland PJ, Leavesley RC, King VR, Bradbury EJ, McMahon SB, Priestley JV. NGF and GDNF ameliorate the increase in ATF3 expression which occurs in dorsal root ganglion cells in response to peripheral nerve injury. Eur J Neurosci 2004; 19:1437-45. [PMID: 15066140 DOI: 10.1111/j.1460-9568.2004.03241.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Activating transcription factor-3 (ATF3) is a member of the ATF/CREB transcription factor superfamily and is induced in dorsal root ganglion (DRG) cells after nerve injury. In order to study the regulation of ATF3, we have examined the effect of nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF) on ATF3 expression. In untreated rats, sciatic nerve transection induced ATF3 immunoreactivity in 82% of L4 DRG cells at 14 days after axotomy. Intrathecal delivery of NGF or GDNF for 2 weeks commencing immediately after injury reduced the ATF3 expression to 35 and 23% of DRG cells, respectively. Cell size analysis indicated that NGF had protected a population of mainly small- to medium-sized cells, but that the GDNF had protected a population of both small and large cells. This effect was confirmed by double labelling for P2X(3), CGRP and 200 kDa neurofilament, markers for small peptide-poor cells, peptide-rich cells and large cells, respectively. Thus GDNF reduced the percentage of ATF3-immunoreactive P2X(3) cells from 70 to 4%, and the percentage of ATF3-immunoreactive neurofilament cells from 63 to 24%. NGF was less effective than GDNF in reducing ATF3 expression in these cell types, but reduced the percentage of ATF3-immunoreactive CGRP cells from 10% to < 1%. These results show that ATF3 expression in specific populations of DRG cells can be modulated by exogenous supplementation of specific trophic factors, and suggest that ATF3 expression may normally be induced by the loss of target-derived NGF and GDNF.
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Affiliation(s)
- Sharon Averill
- Neuroscience Centre, Bart's & The London School of Medicine & Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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Ramer MS, Bradbury EJ, Michael GJ, Lever IJ, McMahon SB. Glial cell line-derived neurotrophic factor increases calcitonin gene-related peptide immunoreactivity in sensory and motoneurons in vivo. Eur J Neurosci 2004; 18:2713-21. [PMID: 14656320 DOI: 10.1111/j.1460-9568.2003.03012.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Calcitonin gene-related peptide (CGRP) is expressed at high levels in roughly 50% of spinal sensory neurons and plays a role in peripheral vasodilation as well as nociceptive signalling in the spinal cord. Spinal motoneurons express low levels of CGRP; motoneuronal CGRP is thought to be involved in end-plate plasticity and to have trophic effects on target muscle cells. As both sensory and motoneurons express receptors for glial cell line-derived neurotrophic factor (GDNF) we sought to determine whether CGRP was regulated by GDNF. Rats were treated intrathecally for 1-3 weeks with recombinant human GDNF or nerve growth factor (NGF) (12 microg/day) and dorsal root ganglia and spinal cords were stained for CGRP. The GDNF treatment not only increased CGRP immunoreactivity in both sensory and motoneurons but also resulted in hypertrophy of both populations. By combined in situ hybridization and immunohistochemistry we found that, in the dorsal root ganglia, CGRP was up-regulated specifically in neurons expressing GDNF but not NGF receptors following GDNF treatment. Despite the increase in CGRP in GDNF-treated rats, there was no increase in thermal or mechanical pain sensitivity, while NGF-treated animals showed significant decreases in pain thresholds. In motoneurons, GDNF increased the overall intensity of CGRP immunoreactivity but did not increase the number of immunopositive cells. As GDNF has been shown to promote the regeneration of both sensory and motor axons, and as CGRP appears to be involved in motoneuronal plasticity, we reason that at least some of the regenerative effects of GDNF are mediated through CGRP up-regulation.
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Affiliation(s)
- Matt S Ramer
- Sensory Function Group, Centre for Neuroscience Research, King's College London, Guy's Campus, London Bridge, London, UK.
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48
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Malcangio M, Getting SJ, Grist J, Cunningham JR, Bradbury EJ, Charbel Issa P, Lever IJ, Pezet S, Perretti M. A novel control mechanism based on GDNF modulation of somatostatin release from sensory neurones. FASEB J 2002; 16:730-2. [PMID: 11978739 DOI: 10.1096/fj.01-0971fje] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Small-diameter sensory neurones found in the rat dorsal root ganglia (DRG) include cells sensitive to glial cell line-derived neurotrophic factor (GDNF), which express the inhibitory peptide somatostatin (SOM). Here we addressed the functional relationship between GDNF and sensory neurone-derived SOM. Topical application of GDNF through the rat isolated dorsal horn of the spinal cord promoted activity-induced release of SOM from central terminals of sensory neurones. Once released by sensory neurones, SOM is known to act, at least in part, by opposing the action of Substance P (SP) in neurogenic inflammation. Therefore, we evaluated GDNF ability to modulate two well-documented effects of peripherally and centrally administered SP. Local application of GDNF in the mouse air pouch reduced SP-induced leukocyte migration. This effect of GDNF was mimicked by the SOM analog octreotide (OCT) and required intact SOM neuronal pools. Intrathecal injection of GDNF activated rat lumbar dorsal horn neurones and inhibited intrathecal SP-induced thermal hypersensitivity. This effect of GDNF was reversed by the SOM antagonist c-SOM and mimicked by OCT. In conclusion we propose GDNF regulation of neuronal SOM release as a novel mechanism that, if explored, may lead to new therapeutic strategies based on local release of somatostatin.
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Affiliation(s)
- Marzia Malcangio
- Neuroscience Research Centre, Guy's, King's and St Thomas' School of Biomedical Sciences, King's College London, London SE1 1UL, UK.
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49
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Bradbury EJ, Moon LDF, Popat RJ, King VR, Bennett GS, Patel PN, Fawcett JW, McMahon SB. Chondroitinase ABC promotes functional recovery after spinal cord injury. Nature 2002; 416:636-40. [PMID: 11948352 DOI: 10.1038/416636a] [Citation(s) in RCA: 1728] [Impact Index Per Article: 78.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The inability of axons to regenerate after a spinal cord injury in the adult mammalian central nervous system (CNS) can lead to permanent paralysis. At sites of CNS injury, a glial scar develops, containing extracellular matrix molecules including chondroitin sulphate proteoglycans (CSPGs). CSPGs are inhibitory to axon growth in vitro, and regenerating axons stop at CSPG-rich regions in vivo. Removing CSPG glycosaminoglycan (GAG) chains attenuates CSPG inhibitory activity. To test the functional effects of degrading chondroitin sulphate (CS)-GAG after spinal cord injury, we delivered chondroitinase ABC (ChABC) to the lesioned dorsal columns of adult rats. We show that intrathecal treatment with ChABC degraded CS-GAG at the injury site, upregulated a regeneration-associated protein in injured neurons, and promoted regeneration of both ascending sensory projections and descending corticospinal tract axons. ChABC treatment also restored post-synaptic activity below the lesion after electrical stimulation of corticospinal neurons, and promoted functional recovery of locomotor and proprioceptive behaviours. Our results demonstrate that CSPGs are important inhibitory molecules in vivo and suggest that their manipulation will be useful for treatment of human spinal injuries.
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Affiliation(s)
- Elizabeth J Bradbury
- Sensory Function Group, Centre for Neuroscience Research, Hodgkin Building, Kings College London, Guy's Campus, London Bridge, London SE1 1UL, UK.
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50
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Charbel Issa P, Lever IJ, Michael GJ, Bradbury EJ, Malcangio M. Intrathecally delivered glial cell line-derived neurotrophic factor produces electrically evoked release of somatostatin in the dorsal horn of the spinal cord. J Neurochem 2001; 78:221-9. [PMID: 11461957 DOI: 10.1046/j.1471-4159.2001.00430.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor with an established role in sensory neuron development. More recently it has also been shown to support adult sensory neuron survival and exert a neuroprotective effect on damaged sensory neurons. Some adult small-sized dorsal root ganglion (DRG) cells that are GDNF-sensitive sensory neurons express the inhibitory peptide somatostatin (SOM). Thus, we tested the hypothesis that prolonged GDNF administration would regulate SOM expression in sensory neuron cell bodies in the dorsal root ganglia (DRG) and activity-induced release of SOM from axon terminals in the dorsal horn. Continuous intrathecal delivery of GDNF for 11-13 days significantly increased the number of small DRG cells that expressed SOM. Furthermore, GDNF treatment evoked SOM release in the isolated dorsal horn following electrical stimulation of the dorsal roots that was otherwise undetectable in control rats. Conversely capsaicin-induced release of SOM (EC(50) 50 nM) was not modified by GDNF treatment. These results show that GDNF can regulate central synaptic function in SOM-containing sensory neurons.
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Affiliation(s)
- P Charbel Issa
- Neuroscience Research Centre, Guy's, King's and St Thomas' School of Biomedical Sciences, King's College London, London, UK
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