1
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Geisler S. Augustus Waller's foresight realized: SARM1 in peripheral neuropathies. Curr Opin Neurobiol 2024; 87:102884. [PMID: 38852438 DOI: 10.1016/j.conb.2024.102884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 06/11/2024]
Abstract
Peripheral neuropathy is a common neurodegenerative condition characterized by numbness, tingling, pain, and weakness that frequently starts in the distal limbs. Arising from multiple etiologies, many peripheral neuropathies exhibit a slowly progressive course due to axon degeneration for which no effective treatments exist. During the past decade, numerous crucial insights into mechanisms of axon degeneration in peripheral neuropathies emerged from experiments involving nerve-cutting procedures, revealing the central role of the SARM1 axon degeneration pathway in both. Here I review commonalities and differences in the role of SARM1 after nerve cut and in several acquired and inherited peripheral neuropathies. This new knowledge now paves the way for the development of therapeutics that directly address root causes of various kinds of neuropathies.
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Affiliation(s)
- Stefanie Geisler
- Department of Neurology, Washington University School of Medicine in St. Louis, 660S. Euclid Ave, Box 8111, St. Louis, MO 63110, USA.
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2
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Schmitd LB, Hafner H, Ward A, Asghari Adib E, Biscola NP, Kohen R, Patel M, Williamson RE, Desai E, Bennett J, Saxman G, Athaiya M, Wilborn D, Shumpert J, Zhao XF, Kawaguchi R, Geschwind DH, Hoke A, Shrager P, Collins CA, Havton LA, Kalinski AL, Giger RJ. Sarm1 is not necessary for activation of neuron-intrinsic growth programs yet required for the Schwann cell repair response and peripheral nerve regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583374. [PMID: 38496662 PMCID: PMC10942360 DOI: 10.1101/2024.03.04.583374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Upon peripheral nervous system (PNS) injury, severed axons undergo rapid SARM1-dependent Wallerian degeneration (WD). In mammals, the role of SARM1 in PNS regeneration, however, is unknown. Here we demonstrate that Sarm1 is not required for axotomy induced activation of neuron-intrinsic growth programs and axonal growth into a nerve crush site. However, in the distal nerve, Sarm1 is necessary for the timely induction of the Schwann cell (SC) repair response, nerve inflammation, myelin clearance, and regeneration of sensory and motor axons. In Sarm1-/- mice, regenerated fibers exhibit reduced axon caliber, defective nerve conduction, and recovery of motor function is delayed. The growth hostile environment of Sarm1-/- distal nerve tissue was demonstrated by grafting of Sarm1-/- nerve into WT recipients. SC lineage tracing in injured WT and Sarm1-/- mice revealed morphological differences. In the Sarm1-/- distal nerve, the appearance of p75NTR+, c-Jun+ SCs is significantly delayed. Ex vivo, p75NTR and c-Jun upregulation in Sarm1-/- nerves can be rescued by pharmacological inhibition of ErbB kinase. Together, our studies show that Sarm1 is not necessary for the activation of neuron intrinsic growth programs but in the distal nerve is required for the orchestration of cellular programs that underlie rapid axon extension.
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Affiliation(s)
- Ligia B. Schmitd
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Hannah Hafner
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Ayobami Ward
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor MI, USA
| | - Elham Asghari Adib
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Natalia P. Biscola
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Manav Patel
- Department of Biology, Ball State University, Muncie IN, USA
| | | | - Emily Desai
- Department of Biology, Ball State University, Muncie IN, USA
| | | | - Grace Saxman
- Department of Biology, Ball State University, Muncie IN, USA
| | - Mitre Athaiya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - David Wilborn
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Jaisha Shumpert
- Department of Biology, Ball State University, Muncie IN, USA
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Riki Kawaguchi
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Daniel H. Geschwind
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Institute of Precision Health, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ahmet Hoke
- Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA
| | - Peter Shrager
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Catherine A. Collins
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Leif A. Havton
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- James J Peters VA Medical Center, Bronx, NY, USA
| | - Ashley L. Kalinski
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Biology, Ball State University, Muncie IN, USA
| | - Roman J. Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor MI, USA
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3
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Krishnan A, Verge VMK, Zochodne DW. Hallmarks of peripheral nerve injury and regeneration. HANDBOOK OF CLINICAL NEUROLOGY 2024; 201:1-17. [PMID: 38697733 DOI: 10.1016/b978-0-323-90108-6.00014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Peripheral nerves are functional networks in the body. Disruption of these networks induces varied functional consequences depending on the types of nerves and organs affected. Despite the advances in microsurgical repair and understanding of nerve regeneration biology, restoring full functions after severe traumatic nerve injuries is still far from achieved. While a blunted growth response from axons and errors in axon guidance due to physical barriers may surface as the major hurdles in repairing nerves, critical additional cellular and molecular aspects challenge the orderly healing of injured nerves. Understanding the systematic reprogramming of injured nerves at the cellular and molecular levels, referred to here as "hallmarks of nerve injury regeneration," will offer better ideas. This chapter discusses the hallmarks of nerve injury and regeneration and critical points of failures in the natural healing process. Potential pharmacological and nonpharmacological intervention points for repairing nerves are also discussed.
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Affiliation(s)
- Anand Krishnan
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada; Cameco MS Neuroscience Research Centre (CMSNRC), Saskatoon, SK, Canada.
| | - Valerie M K Verge
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada; Cameco MS Neuroscience Research Centre (CMSNRC), Saskatoon, SK, Canada.
| | - Douglas W Zochodne
- Neuroscience and Mental Health Institute and Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
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4
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Dehghan S, Kheshtchin N, Hassannezhad S, Soleimani M. Cell death classification: A new insight based on molecular mechanisms. Exp Cell Res 2023; 433:113860. [PMID: 38013091 DOI: 10.1016/j.yexcr.2023.113860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 11/29/2023]
Abstract
Cells tend to disintegrate themselves or are forced to undergo such destructive processes in critical circumstances. This complex cellular function necessitates various mechanisms and molecular pathways in order to be executed. The very nature of cell death is essentially important and vital for maintaining homeostasis, thus any type of disturbing occurrence might lead to different sorts of diseases and dysfunctions. Cell death has various modalities and yet, every now and then, a new type of this elegant procedure gets to be discovered. The diversity of cell death compels the need for a universal organizing system in order to facilitate further studies, therapeutic strategies and the invention of new methods of research. Considering all that, we attempted to review most of the known cell death mechanisms and sort them all into one arranging system that operates under a simple but subtle decision-making (If \ Else) order as a sorting algorithm, in which it decides to place and sort an input data (a type of cell death) into its proper set, then a subset and finally a group of cell death. By proposing this algorithm, the authors hope it may solve the problems regarding newer and/or undiscovered types of cell death and facilitate research and therapeutic applications of cell death.
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Affiliation(s)
- Sepehr Dehghan
- Department of Medical Basic Sciences, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Nasim Kheshtchin
- Department of Immunology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Maryam Soleimani
- Department of Medical Basic Sciences, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
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5
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Funakoshi M, Araki T. Mechanism of initiation and regulation of axonal degeneration with special reference to NMNATs and Sarm1. Neurosci Res 2023; 197:3-8. [PMID: 34767875 DOI: 10.1016/j.neures.2021.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 10/19/2022]
Abstract
Axonal degeneration is observed in a variety of contexts in both the central and peripheral nervous systems. Pathological signaling to regulate the progression of axonal degeneration has long been studied using Wallerian degeneration, the prototypical axonal degradation observed after injury, as a representative model. Understanding metabolism of nicotinamide adenine dinucleotide (NAD+) and the functional regulation of Sarm1 has generated great progress in this field, but there are a number of remaining questions. Here, in this short review, we describe our current understanding of the axonal degeneration mechanism, with special reference to the biology related to wlds mice and Sarm1. Furthermore, variations of axonal degeneration initiation are discussed in order to address the remaining questions needed for mechanistic clarification.
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Affiliation(s)
- Masabumi Funakoshi
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Toshiyuki Araki
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
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6
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Mimic S, Aru B, Pehlivanoğlu C, Sleiman H, Andjus PR, Yanıkkaya Demirel G. Immunology of amyotrophic lateral sclerosis - role of the innate and adaptive immunity. Front Neurosci 2023; 17:1277399. [PMID: 38105925 PMCID: PMC10723830 DOI: 10.3389/fnins.2023.1277399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/07/2023] [Indexed: 12/19/2023] Open
Abstract
This review aims to summarize the latest evidence about the role of innate and adaptive immunity in Amyotrophic Lateral Sclerosis (ALS). ALS is a devastating neurodegenerative disease affecting upper and lower motor neurons, which involves essential cells of the immune system that play a basic role in innate or adaptive immunity, that can be neurotoxic or neuroprotective for neurons. However, distinguishing between the sole neurotoxic or neuroprotective function of certain cells such as astrocytes can be challenging due to intricate nature of these cells, the complexity of the microenvironment and the contextual factors. In this review, in regard to innate immunity we focus on the involvement of monocytes/macrophages, microglia, the complement, NK cells, neutrophils, mast cells, and astrocytes, while regarding adaptive immunity, in addition to humoral immunity the most important features and roles of T and B cells are highlighted, specifically different subsets of CD4+ as well as CD8+ T cells. The role of autoantibodies and cytokines is also discussed in distinct sections of this review.
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Affiliation(s)
- Stefan Mimic
- Centre for Laser Microscopy, Institute of Physiology and Biochemistry “Jean Giaja”, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Başak Aru
- Immunology Department, Faculty of Medicine, Yeditepe University, Istanbul, Türkiye
| | - Cemil Pehlivanoğlu
- Immunology Department, Faculty of Medicine, Yeditepe University, Istanbul, Türkiye
| | - Hadi Sleiman
- Faculty of Medicine, Yeditepe University, Istanbul, Türkiye
| | - Pavle R. Andjus
- Centre for Laser Microscopy, Institute of Physiology and Biochemistry “Jean Giaja”, Faculty of Biology, University of Belgrade, Belgrade, Serbia
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7
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Evans CW, Egid A, Mamsa SSA, Paterson DJ, Ho D, Bartlett CA, Fehily B, Lins BR, Fitzgerald M, Hackett MJ, Smith NM. Elemental Mapping in a Preclinical Animal Model Reveals White Matter Copper Elevation in the Acute Phase of Central Nervous System Trauma. ACS Chem Neurosci 2023; 14:3518-3527. [PMID: 37695072 DOI: 10.1021/acschemneuro.3c00421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023] Open
Abstract
Understanding the chemical events following trauma to the central nervous system could assist in identifying causative mechanisms and potential interventions to protect neural tissue. Here, we apply a partial optic nerve transection model of injury in rats and use synchrotron X-ray fluorescence microscopy (XFM) to perform elemental mapping of metals (K, Ca, Fe, Cu, Zn) and other related elements (P, S, Cl) in white matter tracts. The partial optic nerve injury model and spatial precision of microscopy allow us to obtain previously unattained resolution in mapping elemental changes in response to a primary injury and subsequent secondary effects. We observed significant elevation of Cu levels at multiple time points following the injury, both at the primary injury site and in neural tissue near the injury site vulnerable to secondary damage, as well as significant changes in Cl, K, P, S, and Ca. Our results suggest widespread metal dyshomeostasis in response to central nervous system trauma and that altered Cu homeostasis may be a specific secondary event in response to white matter injury. The findings highlight metal homeostasis as a potential point of intervention in limiting damage following nervous system injury.
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Affiliation(s)
- Cameron W Evans
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Abigail Egid
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Somayra S A Mamsa
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | | | - Diwei Ho
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Carole A Bartlett
- Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Brooke Fehily
- Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- Perron Institute for Neurological and Translational Sciences, 8 Verdun Street, Nedlands, WA 6009, Australia
| | - Brittney R Lins
- Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- Perron Institute for Neurological and Translational Sciences, 8 Verdun Street, Nedlands, WA 6009, Australia
| | - Melinda Fitzgerald
- Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- Perron Institute for Neurological and Translational Sciences, 8 Verdun Street, Nedlands, WA 6009, Australia
| | - Mark J Hackett
- Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Molecular and Life Sciences, Faculty of Science and Engineering, Curtin University, Bentley, WA 6102, Australia
| | - Nicole M Smith
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
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8
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Chen JTC, Hu X, Otto IUC, Schürger C, von Bieberstein BR, Doppler K, Krug SM, Hankir MK, Blasig R, Sommer C, Brack A, Blasig IE, Rittner HL. Myelin barrier breakdown, mechanical hypersensitivity, and painfulness in polyneuropathy with claudin-12 deficiency. Neurobiol Dis 2023; 185:106246. [PMID: 37527762 DOI: 10.1016/j.nbd.2023.106246] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/25/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023] Open
Abstract
BACKGROUND The blood-nerve and myelin barrier shield peripheral neurons and their axons. These barriers are sealed by tight junction proteins, which control the passage of potentially noxious molecules including proinflammatory cytokines via paracellular pathways. Peripheral nerve barrier breakdown occurs in various neuropathies, such as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and traumatic neuropathy. Here, we studied the functional role of the tight junction protein claudin-12 in regulating peripheral nerve barrier integrity and CIDP pathogenesis. METHODS Sections from sural nerve biopsies from 23 patients with CIDP and non-inflammatory idiopathic polyneuropathy (PNP) were analyzed for claudin-12 and -19 immunoreactivity. Cldn12-KO mice were generated and subjected to the chronic constriction injury (CCI) model of neuropathy. These mice were then characterized using a battery of barrier and behavioral tests, histology, immunohistochemistry, and mRNA/protein expression. In phenotype rescue experiments, the proinflammatory cytokine TNFα was neutralized with the anti-TNFα antibody etanercept; the peripheral nerve barrier was stabilized with the sonic hedgehog agonist smoothened (SAG). RESULTS Compared to those without pain, patients with painful neuropathy exhibited reduced claudin-12 expression independently of fiber loss. Accordingly, global Cldn12-KO in male mice, but not fertile female mice, selectively caused mechanical allodynia associated with a leaky myelin barrier, increased TNFα, decreased sonic hedgehog (SHH), and loss of small axons accompanied by reduced peripheral myelin protein 22 (Pmp22). Other barriers and neurological functions remained intact. The Cldn12-KO phenotype could be rescued either by neutralizing TNFα with etanercept or stabilizing the barrier with SAG, which both also upregulated the Schwann cell barrier proteins Cldn19 and Pmp22. CONCLUSION These results point to a critical role for claudin-12 in maintaining the myelin barrier presumably via Pmp22 and highlight restoration of the hedgehog pathway as a potential treatment strategy for painful inflammatory neuropathy.
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Affiliation(s)
- Jeremy Tsung-Chieh Chen
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Xiawei Hu
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Isabel U C Otto
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Christina Schürger
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Bruno Rogalla von Bieberstein
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Kathrin Doppler
- University Hospital Würzburg, Department of Neurology, 97080 Würzburg, Germany
| | - Susanne M Krug
- Charité-Universitätsmedizin Berlin, Clinical Physiology/Nutritional Medicine, 13125 Berlin, Germany
| | - Mohammed K Hankir
- University Hospital Würzburg, Department of General, Transplantation, Visceral, Vascular and Pediatric Surgery, 97080 Würzburg, Germany
| | - Rosel Blasig
- Leibnitz Institute of Molecular Pharmacology, Departments of Molecular Physiology and Cell Biology, 13125 Berlin, Germany
| | - Claudia Sommer
- University Hospital Würzburg, Department of Neurology, 97080 Würzburg, Germany
| | - Alexander Brack
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Ingolf E Blasig
- Leibnitz Institute of Molecular Pharmacology, Departments of Molecular Physiology and Cell Biology, 13125 Berlin, Germany
| | - Heike L Rittner
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany.
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9
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Stocco E, Barbon S, Emmi A, Tiengo C, Macchi V, De Caro R, Porzionato A. Bridging Gaps in Peripheral Nerves: From Current Strategies to Future Perspectives in Conduit Design. Int J Mol Sci 2023; 24:ijms24119170. [PMID: 37298122 DOI: 10.3390/ijms24119170] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
In peripheral nerve injuries (PNI) with substance loss, where tensionless end-to-end suture is not achievable, the positioning of a graft is required. Available options include autografts (e.g., sural nerve, medial and lateral antebrachial cutaneous nerves, superficial branch of the radial nerve), allografts (Avance®; human origin), and hollow nerve conduits. There are eleven commercial hollow conduits approved for clinical, and they consist of devices made of a non-biodegradable synthetic polymer (polyvinyl alcohol), biodegradable synthetic polymers (poly(DL-lactide-ε-caprolactone); polyglycolic acid), and biodegradable natural polymers (collagen type I with/without glycosaminoglycan; chitosan; porcine small intestinal submucosa); different resorption times are available for resorbable guides, ranging from three months to four years. Unfortunately, anatomical/functional nerve regeneration requirements are not satisfied by any of the possible alternatives; to date, focusing on wall and/or inner lumen organization/functionalization seems to be the most promising strategy for next-generation device fabrication. Porous or grooved walls as well as multichannel lumens and luminal fillers are the most intriguing options, eventually also including the addition of cells (Schwann cells, bone marrow-derived, and adipose tissue derived stem cells) to support nerve regeneration. This review aims to describe common alternatives for severe PNI recovery with a highlight of future conduits.
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Affiliation(s)
- Elena Stocco
- Section of Human Anatomy, Department of Neuroscience, University of Padova, 35121 Padova, Italy
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, Padova University Hospital, Via Giustiniani, 2, 35128 Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria (CORIS), Veneto Region, 35128 Padova, Italy
- Foundation for Biology and Regenerative Medicine, Tissue Engineering and Signaling-TES, Onlus, 35030 Padova, Italy
| | - Silvia Barbon
- Section of Human Anatomy, Department of Neuroscience, University of Padova, 35121 Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria (CORIS), Veneto Region, 35128 Padova, Italy
- Foundation for Biology and Regenerative Medicine, Tissue Engineering and Signaling-TES, Onlus, 35030 Padova, Italy
| | - Aron Emmi
- Section of Human Anatomy, Department of Neuroscience, University of Padova, 35121 Padova, Italy
| | - Cesare Tiengo
- Plastic Surgery Unit, Department of Neuroscience, University of Padova, 35121 Padova, Italy
| | - Veronica Macchi
- Section of Human Anatomy, Department of Neuroscience, University of Padova, 35121 Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria (CORIS), Veneto Region, 35128 Padova, Italy
| | - Raffaele De Caro
- Section of Human Anatomy, Department of Neuroscience, University of Padova, 35121 Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria (CORIS), Veneto Region, 35128 Padova, Italy
| | - Andrea Porzionato
- Section of Human Anatomy, Department of Neuroscience, University of Padova, 35121 Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria (CORIS), Veneto Region, 35128 Padova, Italy
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10
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Takenaka T, Ohnishi Y, Yamamoto M, Setoyama D, Kishima H. Glycolytic System in Axons Supplement Decreased ATP Levels after Axotomy of the Peripheral Nerve. eNeuro 2023; 10:ENEURO.0353-22.2023. [PMID: 36894321 PMCID: PMC10035771 DOI: 10.1523/eneuro.0353-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 02/04/2023] [Accepted: 02/25/2023] [Indexed: 03/11/2023] Open
Abstract
Wallerian degeneration (WD) occurs in the early stages of numerous neurologic disorders, and clarifying WD pathology is crucial for the advancement of neurologic therapies. ATP is acknowledged as one of the key pathologic substances in WD. The ATP-related pathologic pathways that regulate WD have been defined. The elevation of ATP levels in axon contributes to delay WD and protects axons. However, ATP is necessary for the active processes to proceed WD, given that WD is stringently managed by auto-destruction programs. But little is known about the bioenergetics during WD. In this study, we made sciatic nerve transection models for GO-ATeam2 knock-in rats and mice. We presented the spatiotemporal ATP distribution in the injured axons with in vivo ATP imaging systems, and investigated the metabolic source of ATP in the distal nerve stump. A gradual decrease in ATP levels was observed before the progression of WD. In addition, the glycolytic system and monocarboxylate transporters (MCTs) were activated in Schwann cells following axotomy. Interestingly, in axons, we found the activation of glycolytic system and the inactivation of the tricarboxylic acid (TCA) cycle. Glycolytic inhibitors, 2-deoxyglucose (2-DG) and MCT inhibitors, a-cyano-4-hydroxycinnamic acid (4-CIN) decreased ATP and enhanced WD progression, whereas mitochondrial pyruvate carrier (MPC) inhibitors (MSDC-0160) did not change. Finally, ethyl pyruvate (EP) increased ATP levels and delayed WD. Together, our findings suggest that glycolytic system, both in Schwann cells and axons, is the main source of maintaining ATP levels in the distal nerve stump.
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Affiliation(s)
- Tomofumi Takenaka
- Department of neurosurgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Department of Research Promotion and Management, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
| | - Yuichiro Ohnishi
- Department of Research Promotion and Management, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
- Department of Neurosurgery, Osaka Gyoumeikan Hospital, Osaka, 554-0012, Japan
| | - Masamichi Yamamoto
- Department of Research Promotion and Management, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
| | - Daiki Setoyama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Haruhiko Kishima
- Department of neurosurgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
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Traumatic axonopathy in spinal tracts after impact acceleration head injury: Ultrastructural observations and evidence of SARM1-dependent axonal degeneration. Exp Neurol 2023; 359:114252. [PMID: 36244414 DOI: 10.1016/j.expneurol.2022.114252] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 11/09/2022]
Abstract
Traumatic axonal injury (TAI) and the associated axonopathy are common consequences of traumatic brain injury (TBI) and contribute to significant neurological morbidity. It has been previously suggested that TAI activates a highly conserved program of axonal self-destruction known as Wallerian degeneration (WD). In the present study, we utilize our well-established impact acceleration model of TBI (IA-TBI) to characterize the pathology of injured myelinated axons in the white matter tracks traversing the ventral, lateral, and dorsal spinal columns in the mouse and assess the effect of Sterile Alpha and TIR Motif Containing 1 (Sarm1) gene knockout on acute and subacute axonal degeneration and myelin pathology. In silver-stained preparations, we found that IA-TBI results in white matter pathology as well as terminal field degeneration across the rostrocaudal axis of the spinal cord. At the ultrastructural level, we found that traumatic axonopathy is associated with diverse types of axonal and myelin pathology, ranging from focal axoskeletal perturbations and focal disruption of the myelin sheath to axonal fragmentation. Several morphological features such as neurofilament compaction, accumulation of organelles and inclusions, axoskeletal flocculation, myelin degeneration and formation of ovoids are similar to profiles encountered in classical examples of WD. Other profiles such as excess myelin figures and inner tongue evaginations are more typical of chronic neuropathies. Stereological analysis of pathological axonal and myelin profiles in the ventral, lateral, and dorsal columns of the lower cervical cord (C6) segments from wild type and Sarm1 KO mice at 3 and 7 days post IA-TBI (n = 32) revealed an up to 90% reduction in the density of pathological profiles in Sarm1 KO mice after IA-TBI. Protection was evident across all white matter tracts assessed, but showed some variability. Finally, Sarm1 deletion ameliorated the activation of microglia associated with TAI. Our findings demonstrate the presence of severe traumatic axonopathy in multiple ascending and descending long tracts after IA-TBI with features consistent with some chronic axonopathies and models of WD and the across-tract protective effect of Sarm1 deletion.
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McGrady NR, Holden JM, Ribeiro M, Boal AM, Risner ML, Calkins DJ. Axon hyperexcitability in the contralateral projection following unilateral optic nerve crush in mice. Brain Commun 2022; 4:fcac251. [PMID: 36267329 PMCID: PMC9576152 DOI: 10.1093/braincomms/fcac251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 08/02/2022] [Accepted: 10/01/2022] [Indexed: 11/07/2022] Open
Abstract
Optic neuropathies are characterized by degeneration of retinal ganglion cell axonal projections to the brain, including acute conditions like optic nerve trauma and progressive conditions such as glaucoma. Despite different aetiologies, retinal ganglion cell axon degeneration in traumatic optic neuropathy and glaucoma share common pathological signatures. We compared how early pathogenesis of optic nerve trauma and glaucoma influence axon function in the mouse optic projection. We assessed pathology by measuring anterograde axonal transport from retina to superior colliculus, current-evoked optic nerve compound action potential and retinal ganglion cell density 1 week following unilateral optic nerve crush or intraocular pressure elevation. Nerve crush reduced axon transport, compound axon potential and retinal ganglion cell density, which were unaffected by intraocular pressure elevation. Surprisingly, optic nerves contralateral to crush demonstrated 5-fold enhanced excitability in compound action potential compared with naïve nerves. Enhanced excitability in contralateral sham nerves is not due to increased accumulation of voltage-gated sodium channel 1.6, or ectopic voltage-gated sodium channel 1.2 expression within nodes of Ranvier. Our results indicate hyperexcitability is driven by intrinsic responses of αON-sustained retinal ganglion cells. We found αON-sustained retinal ganglion cells in contralateral, sham and eyes demonstrated increased responses to depolarizing currents compared with those from naïve eyes, while light-driven responses remained intact. Dendritic arbours of αON-sustained retinal ganglion cells of the sham eye were like naïve, but soma area and non-phosphorylated neurofilament H increased. Current- and light-evoked responses of sham αOFF-sustained retinal ganglion cells remained stable along with somato-dendritic morphologies. In retinas directly affected by crush, light responses of αON- and αOFF-sustained retinal ganglion cells diminished compared with naïve cells along with decreased dendritic field area or branch points. Like light responses, αOFF-sustained retinal ganglion cell current-evoked responses diminished, but surprisingly, αON-sustained retinal ganglion cell responses were similar to those from naïve retinas. Optic nerve crush reduced dendritic length and area in αON-sustained retinal ganglion cells in eyes ipsilateral to injury, while crush significantly reduced dendritic branching in αOFF-sustained retinal ganglion cells. Interestingly, 1 week of intraocular pressure elevation only affected αOFF-sustained retinal ganglion cell physiology, depolarizing resting membrane potential in cells of affected eyes and blunting current-evoked responses in cells of saline-injected eyes. Collectively, our results suggest that neither saline nor sham surgery provide a true control, chronic versus acute optic neuropathies differentially affect retinal ganglion cells composing the ON and OFF pathways, and acute stress can have near-term effects on the contralateral projection.
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Affiliation(s)
- Nolan R McGrady
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Joseph M Holden
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Marcio Ribeiro
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Andrew M Boal
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Michael L Risner
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - David J Calkins
- Correspondence to: David J. Calkins, PhD AA7103 MCN/VUIIS 1161 21st Ave. S., Nashville, TN 37232, USA E-mail:
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Yamamoto Y, Kadoya K, Terkawi MA, Endo T, Konno K, Watanabe M, Ichihara S, Hara A, Kaneko K, Iwasaki N, Ishijima M. Neutrophils delay repair process in Wallerian degeneration by releasing NETs outside the parenchyma. Life Sci Alliance 2022; 5:5/10/e202201399. [PMID: 35961782 PMCID: PMC9375156 DOI: 10.26508/lsa.202201399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 12/05/2022] Open
Abstract
Neutrophils accumulate at the epineurium in Wallerian degeneration (WD) and inhibit macrophage infiltration from the epineurium into the parenchyma by releasing neutrophil extracellular traps, resulting in the delay of repair processes in WD. Although inflammation is indispensable for the repair process in Wallerian degeneration (WD), the role of neutrophils in the WD repair process remains unclear. After peripheral nerve injury, neutrophils accumulate at the epineurium but not the parenchyma in the WD region because of the blood–nerve barrier. An increase or decrease in the number of neutrophils delayed or promoted macrophage infiltration from the epineurium into the parenchyma and the repair process in WD. Abundant neutrophil extracellular traps (NETs) were formed around neutrophils, and its inhibition dramatically increased macrophage infiltration into the parenchyma. Furthermore, inhibition of either MIF or its receptor, CXCR4, in neutrophils decreased NET formation, resulting in enhanced macrophage infiltration into the parenchyma. Moreover, inhibiting MIF for just 2 h after peripheral nerve injury promoted the repair process. These findings indicate that neutrophils delay the repair process in WD from outside the parenchyma by inhibiting macrophage infiltration via NET formation and that neutrophils, NETs, MIF, and CXCR4 are therapeutic targets for peripheral nerve regeneration.
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Affiliation(s)
- Yasuhiro Yamamoto
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.,Department of Medicine for Motor Organ, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Ken Kadoya
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Mohamad Alaa Terkawi
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Takeshi Endo
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kohtarou Konno
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Satoshi Ichihara
- Department of Orthopaedic Surgery, Juntendo University Urayasu Hospital, Urayasu, Japan
| | - Akira Hara
- Department of Orthopaedic Surgery, Juntendo University Urayasu Hospital, Urayasu, Japan
| | - Kazuo Kaneko
- Department of Medicine for Motor Organ, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Norimasa Iwasaki
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Muneaki Ishijima
- Department of Medicine for Motor Organ, Juntendo University Graduate School of Medicine, Tokyo, Japan
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14
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Errante EL, Diaz A, Smartz T, Khan A, Silvera R, Brooks AE, Lee YS, Burks SS, Levi AD. Optimal Technique for Introducing Schwann Cells Into Peripheral Nerve Repair Sites. Front Cell Neurosci 2022; 16:929494. [PMID: 35846565 PMCID: PMC9283978 DOI: 10.3389/fncel.2022.929494] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Peripheral nerve injury (PNI) is found in a relatively large portion of trauma patients. If the injury is severe, such as with the presence of a long segmental gap, PNI can present a challenge for treatment. The current clinical standard of nerve harvest for the repair of long segmental gap PNI can lead to many potential complications. While other methods have been utilized, recent evidence indicates the relevance of cell therapies, particularly through the use of Schwann cells, for the treatment of PNI. Schwann cells (SCs) are integral in the regeneration and restoration of function following PNI. SCs are able to dedifferentiate and proliferate, remove myelin and axonal debris, and are supportive in axonal regeneration. Our laboratory has demonstrated that SCs are effective in the treatment of severe PNI when axon guidance channels are utilized. However, in order for this treatment to be effective, optimal techniques for cellular placement must be used. Thus, here we provide relevant background information, preclinical, and clinical evidence for our method in the treatment of severe PNI through the use of SCs and axon guidance channels.
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Affiliation(s)
- Emily L. Errante
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Anthony Diaz
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Taylor Smartz
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Aisha Khan
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Risset Silvera
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Adriana E. Brooks
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Yee-Shuan Lee
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - S. Shelby Burks
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Allan D. Levi
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Allan D. Levi
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15
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Li B, Zhang Z, Wang H, Zhang D, Han T, Chen H, Chen J, Chen Z, Xie Y, Wang L, Bsoul N, Zhou X, Yan H. Melatonin promotes peripheral nerve repair through Parkin-mediated mitophagy. Free Radic Biol Med 2022; 185:52-66. [PMID: 35504358 DOI: 10.1016/j.freeradbiomed.2022.04.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 10/18/2022]
Abstract
Schwann cells (SCs) are the major glial cells in peripheral nervous system. They unsheathe and myelinate axons and play an essential role in peripheral nerve regeneration. Several studies report that Parkin-mediated mitophagy is associated with various diseases. Melatonin promotes proliferation of central glial cells. Little is known about the effect of melatonin and Parkin-mediated mitophagy on peripheral nerve repair. In this study, using a rat model of a peripheral nerve injury (PNI) and in vitro model established by RSC96 cells treated with tert-butyl hydroperoxide (TBHP), we found that Parkin-mediated mitophagy can effectively reduce the production of mitochondrial reactive oxygen species (ROS), maintain the balance of mitochondrial membrane potential, maintain autophagic flux, and inhibit mitochondrial apoptosis. At the same time, we found that the increase of Parkin under stress is a manifestation of the RSC96 cells' resistance to oxidative stress to maintain RSC96 cells' balance. In our experiment, melatonin is similar to a Parkin agonist, up-regulating the expression of Parkin, enhancing all the positive results of Parkin in a stress state, such as inhibiting active oxygen production, maintaining autophagic flux, and inhibiting mitochondrial apoptosis. In addition, we design in vivo experiments to verify in In vitro experiments. In in vivo, melatonin promotes the expression of Parkin, maintains autophagic flux, inhibits apoptosis, promotes myelin regeneration, reduces the regeneration of collagen fibers around damaged tissues, and promotes peripheral nerve repair. When adenovirus was used to down-regulate the expression of Parkin, we found that all the positive effects of melatonin were attenuated. Collectively, these findings indicate that melatonin upregulates Parkin-mediated mitophagy and promotes peripheral nerve repair. The results provide a basis for development of effective drugs for PNI treatment.
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Affiliation(s)
- Baolong Li
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Zhe Zhang
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Hui Wang
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Dupiao Zhang
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Tao Han
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Hongyu Chen
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Jianpeng Chen
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Zhengtai Chen
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Yutong Xie
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Liang Wang
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Najeeb Bsoul
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China
| | - Xijie Zhou
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
| | - Hede Yan
- Department of Orthopedics (Division of Hand and Microsurgery), The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Key Laboratory of structural malformations in children, Wenzhou, 325000, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
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Kancheva I, Buma F, Kwakkel G, Kancheva A, Ramsey N, Raemaekers M. Investigating secondary white matter degeneration following ischemic stroke by modelling affected fiber tracts. Neuroimage Clin 2022; 33:102945. [PMID: 35124524 PMCID: PMC8829801 DOI: 10.1016/j.nicl.2022.102945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/27/2021] [Accepted: 01/17/2022] [Indexed: 11/27/2022]
Abstract
Secondary white matter degeneration was studied in 11 ischemic stroke patients. We used a custom-developed approach to model damaged fibers associated with a lesion. This approach tackles the inter-subject variability in lesion size and location. Findings suggest that secondary degeneration spreads along an entire fiber’s length.
Secondary white matter degeneration is a common occurrence after ischemic stroke, as identified by Diffusion Tensor Imaging (DTI). However, despite recent advances, the time course of the process is not completely understood. The primary aim of this study was to assess secondary degeneration using an approach whereby we create a patient-specific model of damaged fibers based on the volumetric characteristics of lesions. We also examined the effects of secondary degeneration along the modelled streamlines at different distances from the primary infarction using DTI. Eleven patients who presented with upper limb motor deficits at the time of a first-ever ischemic stroke were included. They underwent scanning at weeks 6 and 29 post-stroke. The fractional anisotropy (FA), mean diffusivity (MD), primary eigenvalue (λ1), and transverse eigenvalue (λ23) were measured. Using regions of interest based on the simulation output, the differences between the modelled fibers and matched contralateral areas were analyzed. The longitudinal change between the two time points and across five distances from the primary lesion was also assessed using the ratios of diffusion quantities (rFA, rMD, rλ1, and rλ23) between the ipsilesional and contralesional hemisphere. At week 6 post-stroke, significantly decreased λ1 was found along the ipsilesional corticospinal tract (CST) with a trend towards lower FA, reduced MD and λ23. At week 29 post-stroke, significantly decreased FA was shown relative to the non-lesioned side, with a trend towards lower λ1, unchanged MD, and higher λ23. Along the ipsilesional tract, the rFA diminished, whereas the rMD, rλ1, and rλ23 significantly increased over time. No significant variations in the time progressive effect with distance were demonstrated. The findings support previously described mechanisms of secondary degeneration and suggest that it spreads along the entire length of a damaged tract. Future investigations using higher-order tractography techniques can further explain the intravoxel alterations caused by ischemic injury.
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Affiliation(s)
- Ivana Kancheva
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, PO Box 85060, 3508AB Utrecht, The Netherlands.
| | - Floor Buma
- Department of Anatomy and Neurosciences, MOVE Research Institute Amsterdam, VU University Medical Center, PO Box 7057, 1007MB Amsterdam, The Netherlands
| | - Gert Kwakkel
- Department of Rehabilitation Medicine, VU University Medical Center, PO Box 7057, 1007MB Amsterdam, The Netherlands
| | - Angelina Kancheva
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, PO Box 85060, 3508AB Utrecht, The Netherlands
| | - Nick Ramsey
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, PO Box 85060, 3508AB Utrecht, The Netherlands
| | - Mathijs Raemaekers
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, PO Box 85060, 3508AB Utrecht, The Netherlands
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Chen H, Jiang L, Zhang D, Chen J, Luo X, Xie Y, Han T, Wang L, Zhang Z, Zhou X, Yan H. Exploring the Correlation Between the Regulation of Macrophages by Regulatory T Cells and Peripheral Neuropathic Pain. Front Neurosci 2022; 16:813751. [PMID: 35237123 PMCID: PMC8882923 DOI: 10.3389/fnins.2022.813751] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectiveIntractable pain after peripheral nerve injury has become a major concern in the field of pain. Current evidence shows that routine medications or surgical treatment is associated with inconsistent results and different curative effects. Stable and effective treatment methods in clinical practice are also lacking. To date, there is no consensus on the pathophysiological mechanisms of pain. The present study investigates the potential regulatory role of regulatory T cells in the differentiation of macrophages on dorsal root ganglion (DRG) and explores the mechanism of nociceptive signals in the signal transfer station. The findings are expected to guide the prevention of various types of peripheral neuropathic pain.MethodsThirty-six male Sprague Dawley (SD) rats and 18 male Nude rats, of equal weight (250–300g), were used in this study. The rats were divided into 3 groups: SD rat sciatic nerve transection group (SNT group, n = 18), SD rat nerve transection experimental group (SNT/RAPA group, n = 18) and Nude rat nerve transection experimental group (SNT/NUDE group, n = 18). The behavior related to neuropathic pain of animals were comprehensively evaluated in all groups. Furthermore, we analyzed the degree of neuroma development, histology, gene, and protein expression, and compared their correlation with the ultrastructural changes of M1/M2 type differentiation of macrophages in DRG.ResultsSciatic nerve transection (SNT), induced the aggregation of several types of macrophages in lumbar DRG of SD rats leading to a higher ratio of M1/M2. Following the inhibition of the M1 type polarization of macrophages, axon outgrowth increased significantly. A significantly lower average autotomy score was reported in the SNT/NUDE group (*p < 0.05) and the SNT/RAPA group (@p < 0.05) as compared to that of the SNT group. The SNT/NUDE group showed no noticeable neuroma formation 30 days after the nerve transection. However, bulbous neuromas were observed in the nerve stumps of both the SNT control and SNT/RAPA groups. Immunofluorescence staining revealed a significant decrease in the proportion of M1/M2 macrophages in lumbar DRG of the SNT/NUDE group (**p < 0.001) and the SNT/RAPA group (@p < 0.05) compared to the SNT group. The expression of pain-related proteins was also decreased (@p < 0.05, *p < 0.05,**p < 0.001). Also, the expression of alpha-smooth muscle actin (α-SMA), neurofilament 200 (NF-200), and nerve growth factor low-affinity receptor p75 were significantly down-regulated in the nerve tissue (@p < 0.05, @@p < 0.001, **p < 0.001).ConclusionM1/M2 type differentiation of macrophages on DRG plays a significant role in the formation of traumatic painful neuroma after neurotomy. In combination with our previous study, the results of this study suggest that regulatory T cells reduce the ratio of M1/M2 macrophages and alleviate the pain of neuroma by regulating the polarization direction of macrophages on neuroma. These findings provide key insights into developing new strategies to manage painful neuroma.
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Affiliation(s)
- Hongyu Chen
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Liangfu Jiang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
| | - Dupiao Zhang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Jianpeng Chen
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Xiaobin Luo
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
| | - Yutong Xie
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Tao Han
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Liang Wang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Zhe Zhang
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- The Second School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Xijie Zhou
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- *Correspondence: Xijie Zhou,
| | - Hede Yan
- Division of Hand Surgery, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Orthopedics of Zhejiang Province, Wenzhou, China
- Hede Yan,
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18
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Lee MW, Jang N, Choi N, Yang S, Jeong J, Nam HS, Oh S, Kim K, Hwang D. In Vivo Cellular-Level 3D Imaging of Peripheral Nerves Using a Dual-Focusing Technique for Intra-Neural Interface Implantation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2102876. [PMID: 34845862 PMCID: PMC8787432 DOI: 10.1002/advs.202102876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/09/2021] [Indexed: 06/13/2023]
Abstract
In vivo volumetric imaging of the microstructural changes of peripheral nerves with an inserted electrode could be key for solving the chronic implantation failure of an intra-neural interface necessary to provide amputated patients with natural motion and sensation. Thus far, no imaging devices can provide a cellular-level three-dimensional (3D) structural images of a peripheral nerve in vivo. In this study, an optical coherence tomography-based peripheral nerve imaging platform that employs a newly proposed depth of focus extension technique is reported. A point spread function with the finest transverse resolution of 1.27 µm enables the cellular-level volumetric visualization of the metal wire and microstructural changes in a rat sciatic nerve with the metal wire inserted in vivo. Further, the feasibility of applying the imaging platform to large animals for a preclinical study is confirmed through in vivo rabbit sciatic nerve imaging. It is expected that new possibilities for the successful chronic implantation of an intra-neural interface will open up by providing the 3D microstructural changes of nerves around the inserted electrode.
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Affiliation(s)
- Min Woo Lee
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Namseon Jang
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Nara Choi
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Sungwook Yang
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Jinwoo Jeong
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Hyeong Soo Nam
- Department of Mechanical EngineeringKorea Advanced Institute of Science and TechnologyDaejeon34141Republic of Korea
| | - Sang‐Rok Oh
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Keehoon Kim
- Department of Mechanical EngineeringPohang University of Science and TechnologyGyeongbuk37673Republic of Korea
| | - Donghyun Hwang
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
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19
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Four Seasons for Schwann Cell Biology, Revisiting Key Periods: Development, Homeostasis, Repair, and Aging. Biomolecules 2021; 11:biom11121887. [PMID: 34944531 PMCID: PMC8699407 DOI: 10.3390/biom11121887] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 01/28/2023] Open
Abstract
Like the seasons of the year, all natural things happen in stages, going through adaptations when challenged, and Schwann cells are a great example of that. During maturation, these cells regulate several steps in peripheral nervous system development. The Spring of the cell means the rise and bloom through organized stages defined by time-dependent regulation of factors and microenvironmental influences. Once matured, the Summer of the cell begins: a high energy stage focused on maintaining adult homeostasis. The Schwann cell provides many neuron-glia communications resulting in the maintenance of synapses. In the peripheral nervous system, Schwann cells are pivotal after injuries, balancing degeneration and regeneration, similarly to when Autumn comes. Their ability to acquire a repair phenotype brings the potential to reconnect axons to targets and regain function. Finally, Schwann cells age, not only by growing old, but also by imposed environmental cues, like loss of function induced by pathologies. The Winter of the cell presents as reduced activity, especially regarding their role in repair; this reflects on the regenerative potential of older/less healthy individuals. This review gathers essential information about Schwann cells in different stages, summarizing important participation of this intriguing cell in many functions throughout its lifetime.
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20
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Sarm1 haploinsufficiency or low expression levels after antisense oligonucleotides delay programmed axon degeneration. Cell Rep 2021; 37:110108. [PMID: 34910914 PMCID: PMC8692746 DOI: 10.1016/j.celrep.2021.110108] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 08/24/2021] [Accepted: 11/17/2021] [Indexed: 12/28/2022] Open
Abstract
Activation of the pro-degenerative protein SARM1 after diverse physical and disease-relevant injuries causes programmed axon degeneration. Original studies indicate that substantially decreased SARM1 levels are required for neuroprotection. However, we demonstrate, in Sarm1 haploinsufficient mice, that lowering SARM1 levels by 50% delays programmed axon degeneration in vivo after sciatic nerve transection and partially prevents neurite outgrowth defects in mice lacking the pro-survival factor NMNAT2. In vitro, the rate of degeneration in response to traumatic, neurotoxic, and genetic triggers of SARM1 activation is also slowed. Finally, we demonstrate that Sarm1 antisense oligonucleotides decrease SARM1 levels by more than 50% in vitro, which delays or prevents programmed axon degeneration. Combining Sarm1 haploinsufficiency with antisense oligonucleotides further decreases SARM1 levels and prolongs protection after neurotoxic injury. These data demonstrate that axon protection occurs in a Sarm1 gene dose-responsive manner and that SARM1-lowering agents have therapeutic potential, making Sarm1-targeting antisense oligonucleotides a promising therapeutic strategy. SARM1-dependent axon degeneration occurs after diverse neurotoxic triggers Silencing one allele of pro-degenerative SARM1 slows programmed axon degeneration Sarm1 ASOs can mimic this, delaying axon degeneration in multiple contexts Decreasing SARM1 expression even partially may be therapeutically valuable
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21
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Yong Y, Hunter-Chang S, Stepanova E, Deppmann C. Axonal spheroids in neurodegeneration. Mol Cell Neurosci 2021; 117:103679. [PMID: 34678457 PMCID: PMC8742877 DOI: 10.1016/j.mcn.2021.103679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 10/20/2022] Open
Abstract
Axonal spheroids are bubble-like biological features that form on most degenerating axons, yet little is known about their influence on degenerative processes. Their formation and growth has been observed in response to various degenerative triggers such as injury, oxidative stress, inflammatory factors, and neurotoxic molecules. They often contain cytoskeletal elements and organelles, and, depending on the pathological insult, can colocalize with disease-related proteins such as amyloid precursor protein (APP), ubiquitin, and motor proteins. Initial formation of axonal spheroids depends on the disruption of axonal and membrane tension governed by cytoskeleton structure and calcium levels. Shortly after spheroid formation, the engulfment signal phosphatidylserine (PS) is exposed on the outer leaflet of spheroid plasma membrane, suggesting an important role for axonal spheroids in phagocytosis and debris clearance during degeneration. Spheroids can grow until they rupture, allowing pro-degenerative factors to exit the axon into extracellular space and accelerating neurodegeneration. Though much remains to be discovered in this area, axonal spheroid research promises to lend insight into the etiologies of neurodegenerative disease, and may be an important target for therapeutic intervention. This review summarizes over 100 years of work, describing what is known about axonal spheroid structure, regulation and function.
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Affiliation(s)
- Yu Yong
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Sarah Hunter-Chang
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Ekaterina Stepanova
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Christopher Deppmann
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA.
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22
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Arthur-Farraj P, Coleman MP. Lessons from Injury: How Nerve Injury Studies Reveal Basic Biological Mechanisms and Therapeutic Opportunities for Peripheral Nerve Diseases. Neurotherapeutics 2021; 18:2200-2221. [PMID: 34595734 PMCID: PMC8804151 DOI: 10.1007/s13311-021-01125-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 12/25/2022] Open
Abstract
Since Waller and Cajal in the nineteenth and early twentieth centuries, laboratory traumatic peripheral nerve injury studies have provided great insight into cellular and molecular mechanisms governing axon degeneration and the responses of Schwann cells, the major glial cell type of peripheral nerves. It is now evident that pathways underlying injury-induced axon degeneration and the Schwann cell injury-specific state, the repair Schwann cell, are relevant to many inherited and acquired disorders of peripheral nerves. This review provides a timely update on the molecular understanding of axon degeneration and formation of the repair Schwann cell. We discuss how nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) and sterile alpha TIR motif containing protein 1 (SARM1) are required for axon survival and degeneration, respectively, how transcription factor c-JUN is essential for the Schwann cell response to nerve injury and what each tells us about disease mechanisms and potential therapies. Human genetic association with NMNAT2 and SARM1 strongly suggests aberrant activation of programmed axon death in polyneuropathies and motor neuron disorders, respectively, and animal studies suggest wider involvement including in chemotherapy-induced and diabetic neuropathies. In repair Schwann cells, cJUN is aberrantly expressed in a wide variety of human acquired and inherited neuropathies. Animal models suggest it limits axon loss in both genetic and traumatic neuropathies, whereas in contrast, Schwann cell secreted Neuregulin-1 type 1 drives onion bulb pathology in CMT1A. Finally, we discuss opportunities for drug-based and gene therapies to prevent axon loss or manipulate the repair Schwann cell state to treat acquired and inherited neuropathies and neuronopathies.
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Affiliation(s)
- Peter Arthur-Farraj
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
| | - Michael P Coleman
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
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23
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Di Pietro M, Russo M, Dono F, Carrarini C, Thomas A, Di Stefano V, Telese R, Bonanni L, Sensi SL, Onofrj M, Franciotti R. A Critical Review of Alien Limb-Related Phenomena and Implications for Functional Magnetic Resonance Imaging Studies. Front Neurol 2021; 12:661130. [PMID: 34566830 PMCID: PMC8458742 DOI: 10.3389/fneur.2021.661130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 07/06/2021] [Indexed: 11/27/2022] Open
Abstract
Consensus criteria on corticobasal degeneration (CBD) include alien limb (AL) phenomena. However, the gist of the behavioral features of AL is still “a matter of debate.” CBD-related AL has so far included the description of involuntary movements, frontal release phenomena (frontal AL), or asomatognosia (posterior or “real” AL). In this context, the most frequent symptoms are language and praxis deficits and cortical sensory misperception. However, asomatognosia requires, by definition, intact perception and cognition. Thus, to make a proper diagnosis of AL in the context of CBD, cognitive and language dysfunctions must be carefully verified and objectively assessed. We reviewed the current literature on AL in CBD and now propose that the generic use of the term AL should be avoided. This catchall AL term should instead be deconstructed. We propose that the term AL is appropriate to describe clinical features associated with specific brain lesions. More discrete sets of regionally bound clinical signs that depend on dysfunctions of specific brain areas need to be assessed and presented when posing the diagnosis. Thus, in our opinion, the AL term should be employed in association with precise descriptions of the accompanying involuntary movements, sensory misperceptions, agnosia-asomatognosia contents, and the presence of utilization behavior. The review also offers an overview of functional magnetic resonance imaging-based studies evaluating AL-related phenomena. In addition, we provide a complementary set of video clips depicting CBD-related involuntary movements that should not mistakenly be interpreted as signs of AL.
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Affiliation(s)
- Martina Di Pietro
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Mirella Russo
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Fedele Dono
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Claudia Carrarini
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Astrid Thomas
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Vincenzo Di Stefano
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, Palermo, Italy
| | - Roberta Telese
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,IRCCS C. Mondino Foundation, Pavia, Italy
| | - Laura Bonanni
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Stefano L Sensi
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy
| | - Marco Onofrj
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technology (CAST), "G. D'Annunzio" University, Chieti, Italy.,YDA Foundation, Institute of Immune Therapy and Advanced Biological Treatment, Pescara, Italy
| | - Raffaella Franciotti
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University of Chieti-Pescara, Chieti, Italy
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24
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Palumbo A, Grüning P, Landt SK, Heckmann LE, Bartram L, Pabst A, Flory C, Ikhsan M, Pietsch S, Schulz R, Kren C, Koop N, Boltze J, Madany Mamlouk A, Zille M. Deep Learning to Decipher the Progression and Morphology of Axonal Degeneration. Cells 2021; 10:cells10102539. [PMID: 34685519 PMCID: PMC8534012 DOI: 10.3390/cells10102539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022] Open
Abstract
Axonal degeneration (AxD) is a pathological hallmark of many neurodegenerative diseases. Deciphering the morphological patterns of AxD will help to understand the underlying mechanisms and develop effective therapies. Here, we evaluated the progression of AxD in cortical neurons using a novel microfluidic device together with a deep learning tool that we developed for the enhanced-throughput analysis of AxD on microscopic images. The trained convolutional neural network (CNN) sensitively and specifically segmented the features of AxD including axons, axonal swellings, and axonal fragments. Its performance exceeded that of the human evaluators. In an in vitro model of AxD in hemorrhagic stroke induced by the hemolysis product hemin, we detected a time-dependent degeneration of axons leading to a decrease in axon area, while axonal swelling and fragment areas increased. Axonal swellings preceded axon fragmentation, suggesting that swellings may be reliable predictors of AxD. Using a recurrent neural network (RNN), we identified four morphological patterns of AxD (granular, retraction, swelling, and transport degeneration). These findings indicate a morphological heterogeneity of AxD in hemorrhagic stroke. Our EntireAxon platform enables the systematic analysis of axons and AxD in time-lapse microscopy and unravels a so-far unknown intricacy in which AxD can occur in a disease context.
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Affiliation(s)
- Alex Palumbo
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, 23562 Lübeck, Germany
| | - Philipp Grüning
- Institute for Neuro- and Bioinformatics, University of Lübeck, 23562 Lübeck, Germany; (P.G.); (A.M.M.)
| | - Svenja Kim Landt
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
| | - Lara Eleen Heckmann
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
| | - Luisa Bartram
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
| | - Alessa Pabst
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
| | - Charlotte Flory
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
| | - Maulana Ikhsan
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, 23562 Lübeck, Germany
- Faculty of Medicine, Malikussaleh University, Lhokseumawe 24355, Indonesia
| | - Sören Pietsch
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
- Department of Neonatology, Universitätsklinikum Leipzig, 04103 Leipzig, Germany
| | - Reinhard Schulz
- Wissenschaftliche Werkstätten, University of Lübeck, 23562 Lübeck, Germany;
| | - Christopher Kren
- Medical Laser Center Lübeck GmbH, 23562 Lübeck, Germany; (C.K.); (N.K.)
| | - Norbert Koop
- Medical Laser Center Lübeck GmbH, 23562 Lübeck, Germany; (C.K.); (N.K.)
| | - Johannes Boltze
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
- School of Life Sciences, The University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, UK
| | - Amir Madany Mamlouk
- Institute for Neuro- and Bioinformatics, University of Lübeck, 23562 Lübeck, Germany; (P.G.); (A.M.M.)
| | - Marietta Zille
- Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, 23562 Lübeck, Germany; (A.P.); (S.K.L.); (L.E.H.); (L.B.); (A.P.); (C.F.); (M.I.); (S.P.); (J.B.)
- Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, 23562 Lübeck, Germany
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, 1090 Vienna, Austria
- Correspondence:
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25
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SARM1-mediated wallerian degeneration: A possible mechanism underlying organophosphorus-induced delayed neuropathy. Med Hypotheses 2021; 155:110666. [PMID: 34455132 DOI: 10.1016/j.mehy.2021.110666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/09/2021] [Accepted: 08/19/2021] [Indexed: 11/20/2022]
Abstract
Some organophosphorus compounds (OPs) can cause a type of delayed neurotoxicity in human being, which is known as organophosphorus-induced delayed neuropathy (OPIDN). Signs and symptoms of the patients include tingling and sensory loss of the hands and feet, followed by progressive muscle weakness in the lower and upper limbs, and ataxia. Pathologically, OPIDN are characterized by distal sensorimotor axonopathy due to the distal axonal degeneration of nerve tracts located in central and peripheral nervous systems. The morphological pattern of the distal axonopathy is similar to Wallerian degeneration that occurs after nerve injury in vitro. It is generally acknowledged that inhibition and subsequent aging of neuropathy target esterase (NTE) is required for the occurrence of OPIDN. However, the underlying mechanisms through which NTE triggers axonal degeneration in OPIDN is still largely unclear. Recently, sterile alpha and toll/interleukin receptor motif-containing protein 1(SARM1) has been identified as a key player in Wallerian degeneration. In physical and chemical transection of axons, SARM1 was found to promotes axon degeneration by hydrolyzing NAD+. By contrast, SARM1 deficiency could prevent neuron degeneration in response to a wide range of insults. Furthermore, SARM1 can also translocate to mitochondria and cause mitochondrial damage, thus triggering axon degeneration and neuron death. These findings suggested the existence of a pathway in axonal degeneration that might be targeted therapeutically. Here, we hypothesize that SARM1 activation after NTE inhibition and aging might be an etiological factor in OPIDN that regulates Wallerian-like degeneration. Analysing SARM1 mediated NAD degeneration pathway and its upstream activators in OPIDN could contribute to the development of novel therapies to treat OPIDN.
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26
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Zhang C, Kang K, Chen Y, Shan S, Xie K, Song F. Atg7 Knockout Alleviated the Axonal Injury of Neuro-2a Cells Induced by Tri-Ortho-Cresyl Phosphate. Neurotox Res 2021; 39:1076-1086. [PMID: 33650059 DOI: 10.1007/s12640-021-00344-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/09/2021] [Accepted: 02/21/2021] [Indexed: 10/22/2022]
Abstract
Autophagy is believed to be essential for the maintenance of axonal homeostasis in neurons. However, whether autophagy is causally related to the axon degeneration in organophosphorus-induced delayed neuropathy (OPIDN) still remains unclear. This research was designed to investigate the role of autophagy in axon degeneration following tri-ortho-cresyl phosphate (TOCP) in an in vitro model. Differentiated wild-type and Atg7-/- neuro-2a (N2a) cells were treated with TOCP for 24 h. Axonal degeneration in N2a cells was quantitatively analyzed; the key molecules responsible for axon degeneration and its upstream signaling pathway were determined by Western blotting and real-time PCR. The results found that Atg7-/- cells exhibited a higher resistance to TOCP insult than wild-type cells. Further study revealed that TOCP caused a significant decrease in pro-survival factors NMNATs and SCG10 and a significant increase in pro-degenerative factor SARM1 in both cells. Notably, Atg7-/- cells presented a higher level of pro-survival factors and a lower level of pro-degenerative factors than wild-type cells in the same setting of TOCP administration. Moreover, DLK-MAPK pathway was activated following TOCP. Altogether, our results suggest that autophagy is able to affect TOCP-induced axonal injury via regulating the balance between pro-survival and pro-degenerative factors, providing a promising avenue for the potential therapy for OPIDN patients.
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Affiliation(s)
- Cuiqin Zhang
- Institute of Toxicology, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong, 250012, People's Republic of China
| | - Kang Kang
- Institute of Toxicology, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong, 250012, People's Republic of China
| | - Yisi Chen
- Institute of Toxicology, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong, 250012, People's Republic of China
| | - Shulin Shan
- Institute of Toxicology, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong, 250012, People's Republic of China
| | - Keqin Xie
- Institute of Toxicology, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong, 250012, People's Republic of China
| | - Fuyong Song
- Institute of Toxicology, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong, 250012, People's Republic of China.
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27
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Hopkins EL, Gu W, Kobe B, Coleman MP. A Novel NAD Signaling Mechanism in Axon Degeneration and its Relationship to Innate Immunity. Front Mol Biosci 2021; 8:703532. [PMID: 34307460 PMCID: PMC8295901 DOI: 10.3389/fmolb.2021.703532] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/28/2021] [Indexed: 12/21/2022] Open
Abstract
Axon degeneration represents a pathological feature of many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease where axons die before the neuronal soma, and axonopathies, such as Charcot-Marie-Tooth disease and hereditary spastic paraplegia. Over the last two decades, it has slowly emerged that a central signaling pathway forms the basis of this process in many circumstances. This is an axonal NAD-related signaling mechanism mainly regulated by the two key proteins with opposing roles: the NAD-synthesizing enzyme NMNAT2, and SARM1, a protein with NADase and related activities. The crosstalk between the axon survival factor NMNAT2 and pro-degenerative factor SARM1 has been extensively characterized and plays an essential role in maintaining the axon integrity. This pathway can be activated in necroptosis and in genetic, toxic or metabolic disorders, physical injury and neuroinflammation, all leading to axon pathology. SARM1 is also known to be involved in regulating innate immunity, potentially linking axon degeneration to the response to pathogens and intercellular signaling. Understanding this NAD-related signaling mechanism enhances our understanding of the process of axon degeneration and enables a path to the development of drugs for a wide range of neurodegenerative diseases.
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Affiliation(s)
- Eleanor L. Hopkins
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Michael P. Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Ren S, Zhang W, Liu H, Wang X, Guan X, Zhang M, Zhang J, Wu Q, Xue Y, Wang D, Liu Y, Liu J, Ren X. Transplantation of a vascularized pedicle of hemisected spinal cord to establish spinal cord continuity after removal of a segment of the thoracic spinal cord: A proof-of-principle study in dogs. CNS Neurosci Ther 2021; 27:1182-1197. [PMID: 34184402 PMCID: PMC8446222 DOI: 10.1111/cns.13696] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/02/2021] [Accepted: 06/06/2021] [Indexed: 12/14/2022] Open
Abstract
Introduction Glial scar formation impedes nerve regeneration/reinnervation after spinal cord injury (SCI); therefore, removal of scar tissue is essential for SCI treatment. Aims To investigate whether removing a spinal cord and transplanting a vascularized pedicle of hemisected spinal cord from the spinal cord caudal to the transection can restore motor function, to aid in the treatment of future clinical spinal cord injuries. We developed a canine model. After removal of a 1‐cm segment of the thoracic (T10–T11) spinal cord in eight beagles, a vascularized pedicle of hemisected spinal cord from the first 1.5 cm of the spinal cord caudal to the transection (cut along the posterior median sulcus of the spinal cord) was transplanted to bridge the transected spinal cord in the presence of a fusogen (polyethylene glycol, PEG) in four of the eight dogs. We used various forms of imaging, electron microscopy, and histologic data to determine that after our transplantation of a vascular pedicled hemisection to bridge the transected spinal cord, electrical continuity across the spinal bridge was restored. Results Motor function was restored following our transplantation, as confirmed by the re‐establishment of anatomic continuity along with interfacial axonal sprouting. Conclusion Taken together, our findings suggest that SCI patients—who have previously been thought to have irreversible damage and/or paralysis—may be treated effectively with similar operative techniques to re‐establish electrical and functional continuity following SCI.
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Affiliation(s)
- Shuai Ren
- Hand and Microsurgery Center, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.,State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Harbin, China.,Global Initiative to Cure Paralysis (GICUP), Columbus, OH, USA
| | - Weihua Zhang
- Global Initiative to Cure Paralysis (GICUP), Columbus, OH, USA.,Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China.,Institute of Orthopedic, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - HongMiao Liu
- Department of Pathology, The General Hospital of Heilongjiang Farms & Land Reclamation Administration Harbin, Harbin, China
| | - Xin Wang
- Department of Pathology, The General Hospital of Heilongjiang Farms & Land Reclamation Administration Harbin, Harbin, China
| | - Xiangchen Guan
- Hand and Microsurgery Center, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.,State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Harbin, China
| | - Mingzhe Zhang
- Hand and Microsurgery Center, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.,State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Harbin, China
| | - Jian Zhang
- Hand and Microsurgery Center, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.,State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Harbin, China
| | - Qiong Wu
- Department of MR Diagnosis, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yan Xue
- Department of Orthopaedics, The Fifth Hospital of Harbin, Harbin, China
| | - Dan Wang
- Department of Pathology, The General Hospital of Heilongjiang Farms & Land Reclamation Administration Harbin, Harbin, China
| | - Yong Liu
- Department of Orthopaedics, The Fifth Hospital of Harbin, Harbin, China
| | - Jianyu Liu
- Hand and Microsurgery Center, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.,State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Harbin, China
| | - Xiaoping Ren
- Global Initiative to Cure Paralysis (GICUP), Columbus, OH, USA.,Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China.,Institute of Orthopedic, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
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Kobayashi M, Zochodne DW. Diabetic polyneuropathy: Bridging the translational gap. J Peripher Nerv Syst 2021; 25:66-75. [PMID: 32573914 DOI: 10.1111/jns.12392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/22/2022]
Abstract
Clinical trials for diabetic polyneuropathy (DPN) have failed to identify therapeutic impacts that have arrested or reversed the disorder, despite a long history. This review considers DPN in the context of a unique neurodegenerative disorder that targets peripheral neurons and their companion glial cells. The approach is to examine what cells, cell substructures, and pathways are implicated in causing DPN and how they might be addressed therapeutically. These include axonopathy, neuronopathy, hyperglycemia, polyol flux, advanced glycation endproduct (AGE)-receptor AGE signaling, growth factor disruption, abnormal insulin signaling, and abnormalities of other intrinsic neuron pathways. Mitochondrial dysfunction and lipid toxicity are largely delegated to the companion review in this issue by Stino and Feldman. Finally, the linkage between axon plasticity of cutaneous nerves, peripheral neuroregenerative pathways, and diabetes are discussed.
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Affiliation(s)
- Masaki Kobayashi
- Department of Neurology, Nissan Tamagawa Hospital, Tokyo, Japan.,Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Douglas W Zochodne
- Division of Neurology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
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30
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Whole-Tissue Immunolabeling and 3D Fluorescence Imaging to Visualize Axon Degeneration in the Intact, Unsectioned Mouse Tissues. Methods Mol Biol 2021. [PMID: 32524484 DOI: 10.1007/978-1-0716-0585-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Axon degeneration destructs functional connectivity of neural circuits and is one of the common, key pathological features of different neurodegenerative diseases. However, conventional histochemistry methods, which largely rely on tissue sections, have intrinsic limitations in examining the 3D distribution of axonal structures on the whole-tissue level. This technical shortcoming has continuously impeded our in-depth understanding of pathological axon degeneration in many scenarios. To overcome such drawback encountered in the research field, we describe here a general protocol of whole-tissue immunolabeling and 3D fluorescence imaging technique to visualize axon degeneration in the intact, unsectioned mouse tissues. In particular, experimental steps of tissue harvesting, whole-tissue immunolabeling, tissue optical clearing, and 3D fluorescence imaging have been systematically optimized, which makes the protocol effective for assessing integrity of the axonal structures in a variety of tissues. Notably, it has enabled the 3D fluorescence imaging of chemotherapy- or traumatic injury-induced axon degeneration within the bones (e.g., femurs) or bone-containing tissues (e.g., hindpaws), which had previously been inaccessible to conventional histochemistry methods. This protocol is therefore readily compatible with many areas of the research on axon degeneration and is poised to serve the field in future investigations.
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31
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Nadeau JR, Arnold BM, Johnston JM, Muir GD, Verge VMK. Acute intermittent hypoxia enhances regeneration of surgically repaired peripheral nerves in a manner akin to electrical stimulation. Exp Neurol 2021; 341:113671. [PMID: 33684407 DOI: 10.1016/j.expneurol.2021.113671] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 02/16/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022]
Abstract
The intrinsic repair response of injured peripheral neurons is enhanced by brief electrical stimulation (ES) at time of surgical repair, resulting in improved regeneration in rodents and humans. However, ES is invasive. Acute intermittent hypoxia (AIH) - breathing alternate cycles of regular air and air with ~50% normal oxygen levels (11% O2), considered mild hypoxia, is an emerging, promising non-invasive therapy that promotes motor function in spinal cord injured rats and humans. AIH can increase neural activity and under moderately severe hypoxic conditions improves repair of peripherally crushed nerves in mice. Thus, we posited an AIH paradigm similar to that used clinically for spinal cord injury, will improve surgically repaired peripheral nerves akin to ES, including an impact on regeneration-associated gene (RAG) expression-a predictor of growth states. Alterations in early RAG expression were examined in adult male Lewis rats that underwent tibial nerve coaptation repair with either 2 days AIH or normoxia control treatment begun on day 2 post-repair, or 1 h ES treatment (20 Hz) at time of repair. Three days post-repair, AIH or ES treatments effected significant and parallel elevated RAG expression relative to normoxia control at the level of injured sensory and motor neuron cell bodies and proximal axon front. These parallel impacts on RAG expression were coupled with significant improvements in later indices of regeneration, namely enhanced myelination and increased numbers of newly myelinated fibers detected 20 mm distal to the tibial nerve repair site or sensory and motor neurons retrogradely labeled 28 mm distal to the repair site, both at 25 days post nerve repair; and improved return of toe spread function 5-10 weeks post-repair. Collectively, AIH mirrors many beneficial effects of ES on peripheral nerve repair outcomes. This highlights its potential for clinical translation as a non-invasive means to effect improved regeneration of injured peripheral nerves.
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Affiliation(s)
- J R Nadeau
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; Biomedical Sciences, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada; Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada
| | - B M Arnold
- Biomedical Sciences, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada; Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada
| | - J M Johnston
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada
| | - G D Muir
- Biomedical Sciences, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada; Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada
| | - V M K Verge
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada.
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Kornfeld T, Nessler J, Helmer C, Hannemann R, Waldmann KH, Peck CT, Hoffmann P, Brandes G, Vogt PM, Radtke C. Spider silk nerve graft promotes axonal regeneration on long distance nerve defect in a sheep model. Biomaterials 2021; 271:120692. [PMID: 33607544 DOI: 10.1016/j.biomaterials.2021.120692] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 01/19/2021] [Accepted: 01/26/2021] [Indexed: 12/21/2022]
Abstract
Peripheral nerve injuries with substantial tissue loss require autologous nerve transplantation or alternatively reconstruction with nerve conduits. Axonal elongation after nerve transection is about 1 mm/day. The precise time course of axonal regeneration on an ultrastructural level in nerve gap repair using either autologous or artificial implants has not been described. As peripheral nerve regeneration is a highly time critical process due to deterioration of the neuromuscular junction, this in vivo examination in a large animal model was performed in order to investigate axonal elongation rates and spider silk material degradation in a narrowly delimited time series (20, 30, 40, 50, 90, 120, 150 and 180 days) by using a novel spider silk based artificial nerve graft as a critical prerequisite for clinical translation. Autologous nerves or artificial nerve conduits based on spider silk of the spider species Trichonephila edulis were transplanted in a 6.0 cm nerve defect model in the black headed mutton. At each of the post-implant time point, electrophysiology recordings were performed to assess functional reinnervation of axonal fibers into the implants. Samples were analyzed by histology and immunofluorescence in order to verify the timeline of axonal regeneration including axonal regeneration rates of the spider silk implant and the autologous transplant groups. Spider silk was degraded within 3 month by a light immune response mainly mediated by Langhans Giant cells. In conjunction with behavioral analysis and electrophysiological measurements, the results indicate that the spider silk nerve implant supported an axonal regeneration comparable to an autologous nerve graft which is the current gold standard in nerve repair surgery. These findings indicate that a biomaterial based spider silk nerve conduit is as effective as autologous nerve implants and may be an important approach for long nerve defects.
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Affiliation(s)
- T Kornfeld
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany; Department of Plastic, and Reconstructive Surgery, Medical School of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - J Nessler
- Clinic for Small Animals, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany
| | - C Helmer
- Clinic for Swine and Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Hannover, Germany
| | - R Hannemann
- Clinic for Swine and Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Hannover, Germany
| | - K H Waldmann
- Clinic for Swine and Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Hannover, Germany
| | - C T Peck
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - P Hoffmann
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - G Brandes
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - P M Vogt
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - C Radtke
- Department of Plastic, Aesthetic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany; Department of Plastic, and Reconstructive Surgery, Medical School of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.
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Balakrishnan A, Belfiore L, Chu TH, Fleming T, Midha R, Biernaskie J, Schuurmans C. Insights Into the Role and Potential of Schwann Cells for Peripheral Nerve Repair From Studies of Development and Injury. Front Mol Neurosci 2021; 13:608442. [PMID: 33568974 PMCID: PMC7868393 DOI: 10.3389/fnmol.2020.608442] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/31/2020] [Indexed: 12/13/2022] Open
Abstract
Peripheral nerve injuries arising from trauma or disease can lead to sensory and motor deficits and neuropathic pain. Despite the purported ability of the peripheral nerve to self-repair, lifelong disability is common. New molecular and cellular insights have begun to reveal why the peripheral nerve has limited repair capacity. The peripheral nerve is primarily comprised of axons and Schwann cells, the supporting glial cells that produce myelin to facilitate the rapid conduction of electrical impulses. Schwann cells are required for successful nerve regeneration; they partially “de-differentiate” in response to injury, re-initiating the expression of developmental genes that support nerve repair. However, Schwann cell dysfunction, which occurs in chronic nerve injury, disease, and aging, limits their capacity to support endogenous repair, worsening patient outcomes. Cell replacement-based therapeutic approaches using exogenous Schwann cells could be curative, but not all Schwann cells have a “repair” phenotype, defined as the ability to promote axonal growth, maintain a proliferative phenotype, and remyelinate axons. Two cell replacement strategies are being championed for peripheral nerve repair: prospective isolation of “repair” Schwann cells for autologous cell transplants, which is hampered by supply challenges, and directed differentiation of pluripotent stem cells or lineage conversion of accessible somatic cells to induced Schwann cells, with the potential of “unlimited” supply. All approaches require a solid understanding of the molecular mechanisms guiding Schwann cell development and the repair phenotype, which we review herein. Together these studies provide essential context for current efforts to design glial cell-based therapies for peripheral nerve regeneration.
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Affiliation(s)
- Anjali Balakrishnan
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lauren Belfiore
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Tak-Ho Chu
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Taylor Fleming
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada
| | - Rajiv Midha
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jeff Biernaskie
- Department of Comparative Biology and Experimental Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Carol Schuurmans
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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Canty AJ, Jackson JS, Huang L, Trabalza A, Bass C, Little G, Tortora M, Khan S, De Paola V. In vivo imaging of injured cortical axons reveals a rapid onset form of Wallerian degeneration. BMC Biol 2020; 18:170. [PMID: 33208154 PMCID: PMC7677840 DOI: 10.1186/s12915-020-00869-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 09/16/2020] [Indexed: 12/22/2022] Open
Abstract
Background Despite the widespread occurrence of axon and synaptic loss in the injured and diseased nervous system, the cellular and molecular mechanisms of these key degenerative processes remain incompletely understood. Wallerian degeneration (WD) is a tightly regulated form of axon loss after injury, which has been intensively studied in large myelinated fibre tracts of the spinal cord, optic nerve and peripheral nervous system (PNS). Fewer studies, however, have focused on WD in the complex neuronal circuits of the mammalian brain, and these were mainly based on conventional endpoint histological methods. Post-mortem analysis, however, cannot capture the exact sequence of events nor can it evaluate the influence of elaborated arborisation and synaptic architecture on the degeneration process, due to the non-synchronous and variable nature of WD across individual axons. Results To gain a comprehensive picture of the spatiotemporal dynamics and synaptic mechanisms of WD in the nervous system, we identify the factors that regulate WD within the mouse cerebral cortex. We combined single-axon-resolution multiphoton imaging with laser microsurgery through a cranial window and a fluorescent membrane reporter. Longitudinal imaging of > 150 individually injured excitatory cortical axons revealed a threshold length below which injured axons consistently underwent a rapid-onset form of WD (roWD). roWD started on average 20 times earlier and was executed 3 times slower than WD described in other regions of the nervous system. Cortical axon WD and roWD were dependent on synaptic density, but independent of axon complexity. Finally, pharmacological and genetic manipulations showed that a nicotinamide adenine dinucleotide (NAD+)-dependent pathway could delay cortical roWD independent of transcription in the damaged neurons, demonstrating further conservation of the molecular mechanisms controlling WD in different areas of the mammalian nervous system. Conclusions Our data illustrate how in vivo time-lapse imaging can provide new insights into the spatiotemporal dynamics and synaptic mechanisms of axon loss and assess therapeutic interventions in the injured mammalian brain.
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Affiliation(s)
- Alison Jane Canty
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Australia.
| | - Johanna Sara Jackson
- Dementia Research Institute at Imperial College, Department of Brain Sciences, Imperial College London, London, W12 0NN, UK
| | - Lieven Huang
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Antonio Trabalza
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Cher Bass
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Graham Little
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Maria Tortora
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Shabana Khan
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Vincenzo De Paola
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK. .,Medical Research Council London Institute of Medical Sciences, London, W12 0NN, UK.
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Nocera G, Jacob C. Mechanisms of Schwann cell plasticity involved in peripheral nerve repair after injury. Cell Mol Life Sci 2020; 77:3977-3989. [PMID: 32277262 PMCID: PMC7532964 DOI: 10.1007/s00018-020-03516-9] [Citation(s) in RCA: 208] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 03/09/2020] [Accepted: 03/30/2020] [Indexed: 01/01/2023]
Abstract
The great plasticity of Schwann cells (SCs), the myelinating glia of the peripheral nervous system (PNS), is a critical feature in the context of peripheral nerve regeneration following traumatic injuries and peripheral neuropathies. After a nerve damage, SCs are rapidly activated by injury-induced signals and respond by entering the repair program. During the repair program, SCs undergo dynamic cell reprogramming and morphogenic changes aimed at promoting nerve regeneration and functional recovery. SCs convert into a repair phenotype, activate negative regulators of myelination and demyelinate the damaged nerve. Moreover, they express many genes typical of their immature state as well as numerous de-novo genes. These genes modulate and drive the regeneration process by promoting neuronal survival, damaged axon disintegration, myelin clearance, axonal regrowth and guidance to their former target, and by finally remyelinating the regenerated axon. Many signaling pathways, transcriptional regulators and epigenetic mechanisms regulate these events. In this review, we discuss the main steps of the repair program with a particular focus on the molecular mechanisms that regulate SC plasticity following peripheral nerve injury.
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Affiliation(s)
- Gianluigi Nocera
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany
| | - Claire Jacob
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany.
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36
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Kerns JM, Walter JS, Patetta MJ, Sood A, Hussain AK, Chung JJ, Deshpande A, DesLaurier JT, Dieter RA, Siemionow M, Seiler FA, Amirouche FML, Gonzalez MH. Histological Assessment of Wallerian Degeneration of the Rat Tibial Nerve Following Crush and Transection Injuries. J Reconstr Microsurg 2020; 37:391-404. [PMID: 32971546 DOI: 10.1055/s-0040-1716870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Wallerian degeneration (WD) following peripheral nerve injury (PNI) is an area of growing focus for pharmacological developments. Clinically, WD presents challenges in achieving full functional recovery following PNI, as prolonged denervation of distal tissues for an extended period of time can irreversibly destabilize sensory and motor targets with secondary tissue atrophy. Our objective is to improve upon histological assessments of WD. METHODS Conventional methods utilize a qualitative system simply describing the presence or absence of WD in nerve fibers. We propose a three-category assessment that allows more quantification: A fibers appear normal, B fibers have moderate WD (altered axoplasm), and C fibers have extensive WD (myelin figures). Analysis was by light microscopy (LM) on semithin sections stained with toluidine blue in three rat tibial nerve lesion models (crush, partial transection, and complete transection) at 5 days postop and 5 mm distal to the injury site. The LM criteria were verified at the ultrastructural level. This early outcome measure was compared with the loss of extensor postural thrust and the absence of muscle atrophy. RESULTS The results showed good to excellent internal consistency among counters, demonstrating a significant difference between the crush and transection lesion models. A significant decrease in fiber density in the injured nerves due to inflammation/edema was observed. The growth cones of regenerating axons were evident in the crush lesion group. CONCLUSION The ABC method of histological assessment is a consistent and reliable method that will be useful to quantify the effects of different interventions on the WD process.
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Affiliation(s)
- James M Kerns
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
| | - James S Walter
- Hines Veterans Affairs Hospital Research Service, Hines, Illinois
| | - Michael J Patetta
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
| | - Anshum Sood
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
| | - Awais K Hussain
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
| | - Joyce J Chung
- University of Illinois College of Medicine, Chicago, Illinois
| | | | | | - Raymond A Dieter
- Hines Veterans Affairs Hospital Research Service, Hines, Illinois
| | - Maria Siemionow
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
| | - Figen A Seiler
- Research Resources Center, University of Illinois Chicago, Chicago, Illinois
| | - Farid M L Amirouche
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
| | - Mark H Gonzalez
- Department Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois
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37
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Yong Y, Gamage K, Cushman C, Spano A, Deppmann C. Regulation of degenerative spheroids after injury. Sci Rep 2020; 10:15472. [PMID: 32963272 PMCID: PMC7508847 DOI: 10.1038/s41598-020-71906-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/05/2020] [Indexed: 12/26/2022] Open
Abstract
Neuronal injury leads to rapid, programmed disintegration of axons distal to the site of lesion. Much like other forms of axon degeneration (e.g. developmental pruning, toxic insult from neurodegenerative disorder), Wallerian degeneration associated with injury is preceded by spheroid formation along axons. The mechanisms by which injury leads to formation of spheroids and whether these spheroids have a functional role in degeneration remain elusive. Here, using neonatal mouse primary sympathetic neurons, we investigate the roles of players previously implicated in the progression of Wallerian degeneration in injury-induced spheroid formation. We find that intra-axonal calcium flux is accompanied by actin-Rho dependent growth of calcium rich axonal spheroids that eventually rupture, releasing material to the extracellular space prior to catastrophic axon degeneration. Importantly, after injury, Sarm1-/- and DR6-/-, but not Wlds (excess NAD+) neurons, are capable of forming spheroids that eventually rupture, releasing their contents to the extracellular space to promote degeneration. Supplementation of exogenous NAD+ or expressing WLDs suppresses Rho-dependent spheroid formation and degeneration in response to injury. Moreover, injured or trophically deprived Sarm1-/- and DR6-/-, but not Wlds neurons, are resistant to degeneration induced by conditioned media collected from wild-type axons after spheroid rupture. Taken together, these findings place Rho-actin and NAD+ upstream of spheroid formation and may suggest that other mediators of degeneration, such as DR6 and SARM1, mediate post-spheroid rupture events that lead to catastrophic axon disassembly.
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Affiliation(s)
- Yu Yong
- Department of Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA
| | - Kanchana Gamage
- Amgen, Massachusetts and Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Courtny Cushman
- Department of Neuroscience and Biomedical Engineering, University of Virginia, Charlottesville, VA, 22904-4328, USA
| | - Anthony Spano
- Department of Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA
| | - Christopher Deppmann
- Department of Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA.
- Department of Neuroscience and Biomedical Engineering, University of Virginia, Charlottesville, VA, 22904-4328, USA.
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA.
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A glycolytic shift in Schwann cells supports injured axons. Nat Neurosci 2020; 23:1215-1228. [PMID: 32807950 DOI: 10.1038/s41593-020-0689-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 07/07/2020] [Indexed: 01/09/2023]
Abstract
Axon degeneration is a hallmark of many neurodegenerative disorders. The current assumption is that the decision of injured axons to degenerate is cell-autonomously regulated. Here we show that Schwann cells (SCs), the glia of the peripheral nervous system, protect injured axons by virtue of a dramatic glycolytic upregulation that arises in SCs as an inherent adaptation to axon injury. This glycolytic response, paired with enhanced axon-glia metabolic coupling, supports the survival of axons. The glycolytic shift in SCs is largely driven by the metabolic signaling hub, mammalian target of rapamycin complex 1, and the downstream transcription factors hypoxia-inducible factor 1-alpha and c-Myc, which together promote glycolytic gene expression. The manipulation of glial glycolytic activity through this pathway enabled us to accelerate or delay the degeneration of perturbed axons in acute and subacute rodent axon degeneration models. Thus, we demonstrate a non-cell-autonomous metabolic mechanism that controls the fate of injured axons.
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Microstructural Changes in Compressed Cervical Spinal Cord Are Consistent With Clinical Symptoms and Symptom Duration. Spine (Phila Pa 1976) 2020; 45:E999-E1005. [PMID: 32706563 DOI: 10.1097/brs.0000000000003480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A prospective study. OBJECTIVE To investigate the association between microstructural changes measured by diffusion tensor imaging (DTI) and clinical symptoms and their duration in patients with cervical spondylotic myelopathy (CSM) affected by single level. SUMMARY OF BACKGROUND DATA No report was reported regarding the association between the microstructural changes and the symptoms and their duration at single-level spinal cord compression. METHODS Twenty-nine consecutive patients with CSM and 29 normal subjects were enrolled in this study. DTI with tractography was performed on the cervical spinal cord. Clinical symptoms were evaluated using modified Japanese Orthopaedic Association (mJOA) scores for each patient, and the duration of clinical symptoms was noted based on the earliest instance of limb pain or numbness or weakness or bladder dysfunction. Mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from tractography images. RESULTS The mean FA value of the cervical compressed spinal cord was significantly lower than the FA of the normal population (P < 0.001). The mean ADC value in the cervical compressed spinal cord was obviously higher than those of normal cervical spinal cord (P < 0.001). In the CSM patients, a significant positive association was observed between FA values and mJOA scores (P < 0.001). However, there were a notable negative association between mJOA scores and ADC values (P < 0.001), and between mJOA scores and symptom duration (P < 0.001). CONCLUSION These results illustrate DTI can measure the micostructural changes of cervical spinal cord and DTI parameters are potential biomarkers for spinal cord dysfunction in patients with CSM. LEVEL OF EVIDENCE 3.
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Vaquié A, Sauvain A, Duman M, Nocera G, Egger B, Meyenhofer F, Falquet L, Bartesaghi L, Chrast R, Lamy CM, Bang S, Lee SR, Jeon NL, Ruff S, Jacob C. Injured Axons Instruct Schwann Cells to Build Constricting Actin Spheres to Accelerate Axonal Disintegration. Cell Rep 2020; 27:3152-3166.e7. [PMID: 31189102 DOI: 10.1016/j.celrep.2019.05.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/11/2019] [Accepted: 05/17/2019] [Indexed: 01/26/2023] Open
Abstract
After a peripheral nerve lesion, distal ends of injured axons disintegrate into small fragments that are subsequently cleared by Schwann cells and later by macrophages. Axonal debris clearing is an early step of the repair process that facilitates regeneration. We show here that Schwann cells promote distal cut axon disintegration for timely clearing. By combining cell-based and in vivo models of nerve lesion with mouse genetics, we show that this mechanism is induced by distal cut axons, which signal to Schwann cells through PlGF mediating the activation and upregulation of VEGFR1 in Schwann cells. In turn, VEGFR1 activates Pak1, leading to the formation of constricting actomyosin spheres along unfragmented distal cut axons to mediate their disintegration. Interestingly, oligodendrocytes can acquire a similar behavior as Schwann cells by enforced expression of VEGFR1. These results thus identify controllable molecular cues of a neuron-glia crosstalk essential for timely clearing of damaged axons.
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Affiliation(s)
- Adrien Vaquié
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Alizée Sauvain
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Mert Duman
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gianluigi Nocera
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Boris Egger
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Bioimage Light Microscopy Facility, University of Fribourg, Fribourg, Switzerland
| | - Felix Meyenhofer
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Medicine, University of Fribourg, Fribourg, Switzerland; Bioimage Light Microscopy Facility, University of Fribourg, Fribourg, Switzerland
| | - Laurent Falquet
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Medicine, University of Fribourg, Fribourg, Switzerland; Bioinformatics Core Facility, University of Fribourg and Swiss Institute of Bioinformatics, Fribourg, Switzerland
| | - Luca Bartesaghi
- Departments of Neuroscience and Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Roman Chrast
- Departments of Neuroscience and Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Seokyoung Bang
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea
| | - Seung-Ryeol Lee
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea
| | - Noo Li Jeon
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea
| | - Sophie Ruff
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Claire Jacob
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Biology, Johannes Gutenberg University Mainz, Mainz, Germany.
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O'Reilly ML, Tom VJ. Neuroimmune System as a Driving Force for Plasticity Following CNS Injury. Front Cell Neurosci 2020; 14:187. [PMID: 32792908 PMCID: PMC7390932 DOI: 10.3389/fncel.2020.00187] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/29/2020] [Indexed: 12/15/2022] Open
Abstract
Following an injury to the central nervous system (CNS), spontaneous plasticity is observed throughout the neuraxis and affects multiple key circuits. Much of this spontaneous plasticity can elicit beneficial and deleterious functional outcomes, depending on the context of plasticity and circuit affected. Injury-induced activation of the neuroimmune system has been proposed to be a major factor in driving this plasticity, as neuroimmune and inflammatory factors have been shown to influence cellular, synaptic, structural, and anatomical plasticity. Here, we will review the mechanisms through which the neuroimmune system mediates plasticity after CNS injury. Understanding the role of specific neuroimmune factors in driving adaptive and maladaptive plasticity may offer valuable therapeutic insight into how to promote adaptive plasticity and/or diminish maladaptive plasticity, respectively.
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Affiliation(s)
- Micaela L O'Reilly
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
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Stassart RM, Woodhoo A. Axo-glial interaction in the injured PNS. Dev Neurobiol 2020; 81:490-506. [PMID: 32628805 DOI: 10.1002/dneu.22771] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Axons share a close relationship with Schwann cells, their glial partners in peripheral nerves. An intricate axo-glia network of signals and bioactive molecules regulates the major aspects of nerve development and normal functioning of the peripheral nervous system. Disruptions to these complex axo-glial interactions can have serious neurological consequences, as typically seen in injured nerves. Recent studies in inherited neuropathies have demonstrated that damage to one of the partners in this symbiotic unit ultimately leads to impairment of the other partner, emphasizing the bidirectional influence of axon to glia and glia to axon signaling in these diseases. After physical trauma to nerves, dramatic alterations in the architecture and signaling environment of peripheral nerves take place. Here, axons and Schwann cells respond adaptively to these perturbations and change the nature of their reciprocal interactions, thereby driving the remodeling and regeneration of peripheral nerves. In this review, we focus on the nature and importance of axon-glia interactions in injured nerves, both for the reshaping and repair of nerves after trauma, and in driving pathology in inherited peripheral neuropathies.
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Affiliation(s)
- Ruth M Stassart
- Department of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Ashwin Woodhoo
- Nerve Disorders Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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43
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Brown BL, Sandelski MM, Drejet SM, Runge EM, Shipchandler TZ, Jones KJ, Walker CL. Facial nerve repair utilizing intraoperative repair strategies. Laryngoscope Investig Otolaryngol 2020; 5:552-559. [PMID: 32596500 PMCID: PMC7314485 DOI: 10.1002/lio2.411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/27/2020] [Accepted: 05/18/2020] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES To determine whether functional and anatomical outcomes following suture neurorrhaphy are improved by the addition of electrical stimulation with or without the addition of polyethylene glycol (PEG). METHODS In a rat model of facial nerve injury, complete facial nerve transection and repair was performed via (a) suture neurorrhaphy alone, (b) neurorrhaphy with the addition of brief (30 minutes) intraoperative electrical stimulation, or (c) neurorrhaphy with the addition electrical stimulation and PEG. Functional recovery was assessed weekly for 16 weeks. At 16 weeks postoperatively, motoneuron survival, amount of regrowth, and specificity of regrowth were assessed by branch labeling and tissue analysis. RESULTS The addition of brief intraoperative electrical stimulation improved all functional outcomes compared to suturing alone. The addition of PEG to electrical stimulation impaired this benefit. Motoneuron survival, amount of regrowth, and specificity of regrowth were unaltered at 16 weeks postoperative in all treatment groups. CONCLUSION The addition of brief intraoperative electrical stimulation to neurorrhaphy in this rodent model shows promising neurological benefit in the surgical repair of facial nerve injury. LEVEL OF EVIDENCE Animal study.
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Affiliation(s)
- Brandon L. Brown
- Department of Anatomy, Cell Biology and PhysiologyIndiana University School of MedicineIndianapolisIndianaUSA
- Department of Anatomical Sciences and NeurobiologyUniversity of LouisvilleLouisvilleKentuckyUSA
| | - Morgan M. Sandelski
- Department of Anatomy, Cell Biology and PhysiologyIndiana University School of MedicineIndianapolisIndianaUSA
| | - Sarah M. Drejet
- Department of OtolaryngologyIndiana University School of MedicineIndianapolisIndianaUSA
| | - Elizabeth M. Runge
- Department of Anatomy, Cell Biology and PhysiologyIndiana University School of MedicineIndianapolisIndianaUSA
| | - Taha Z. Shipchandler
- Department of OtolaryngologyIndiana University School of MedicineIndianapolisIndianaUSA
| | - Kathryn J. Jones
- Department of Anatomy, Cell Biology and PhysiologyIndiana University School of MedicineIndianapolisIndianaUSA
- Research and Development ServiceRichard L Roudebush Veterans Affairs Medical CenterIndianapolisIndianaUSA
| | - Chandler L. Walker
- Department of Anatomy, Cell Biology and PhysiologyIndiana University School of MedicineIndianapolisIndianaUSA
- Research and Development ServiceRichard L Roudebush Veterans Affairs Medical CenterIndianapolisIndianaUSA
- Department of Biomedical Sciences and Comprehensive CareIndiana University School of DentistryIndianapolisIndianaUSA
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Grove M, Lee H, Zhao H, Son YJ. Axon-dependent expression of YAP/TAZ mediates Schwann cell remyelination but not proliferation after nerve injury. eLife 2020; 9:50138. [PMID: 32436841 PMCID: PMC7259960 DOI: 10.7554/elife.50138] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 05/19/2020] [Indexed: 12/18/2022] Open
Abstract
Previously we showed that YAP/TAZ promote not only proliferation but also differentiation of immature Schwann cells (SCs), thereby forming and maintaining the myelin sheath around peripheral axons (Grove et al., 2017). Here we show that YAP/TAZ are required for mature SCs to restore peripheral myelination, but not to proliferate, after nerve injury. We find that YAP/TAZ dramatically disappear from SCs of adult mice concurrent with axon degeneration after nerve injury. They reappear in SCs only if axons regenerate. YAP/TAZ ablation does not impair SC proliferation or transdifferentiation into growth promoting repair SCs. SCs lacking YAP/TAZ, however, fail to upregulate myelin-associated genes and completely fail to remyelinate regenerated axons. We also show that both YAP and TAZ are redundantly required for optimal remyelination. These findings suggest that axons regulate transcriptional activity of YAP/TAZ in adult SCs and that YAP/TAZ are essential for functional regeneration of peripheral nerve.
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Affiliation(s)
- Matthew Grove
- Shriners Hospitals Pediatric Research Center and Center for Neural Repair and Rehabilitation, Temple University, Philadelphia, United States.,Department of Anatomy and Cell Biology, Temple University, Philadelphia, United States
| | - Hyunkyoung Lee
- Shriners Hospitals Pediatric Research Center and Center for Neural Repair and Rehabilitation, Temple University, Philadelphia, United States.,Department of Anatomy and Cell Biology, Temple University, Philadelphia, United States
| | - Huaqing Zhao
- Department of Clinical Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, United States
| | - Young-Jin Son
- Shriners Hospitals Pediatric Research Center and Center for Neural Repair and Rehabilitation, Temple University, Philadelphia, United States.,Department of Anatomy and Cell Biology, Temple University, Philadelphia, United States
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45
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Kesim-Sahin O, Sirin NG, Erbas B, Artug T, Oguz-Akarsu E, Kocasoy-Orhan E, Baslo MB, Mammadova N, Emekli U, Oge AE. Compound muscle action potential scan and MScanFit motor unit number estimation during Wallerian degeneration after nerve transections. Muscle Nerve 2020; 62:239-246. [PMID: 32415858 DOI: 10.1002/mus.26923] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND Compound muscle action potential (CMAP) scan and MScanFit have been used to understand the consequences of denervation and reinnervation. This study aimed to monitor these parameters during Wallerian degeneration (WD) after acute nerve transections (ANT). METHODS Beginning after urgent surgery, CMAP scans were recorded at 1-2 day intervals in 12 patients with ANT of the ulnar or median nerves, by stimulating the distal stump (DS). Stimulus intensities (SI), steps, returners, and MScanFit were calculated. Studies were grouped according to the examination time after ANT. Results were compared with those of 27 controls. RESULTS CMAP amplitudes and MScanFit progressively declined, revealing a positive correlation with one another. SIs were higher in WD groups than controls. Steps appeared or disappeared in follow-up scans. The late WD group had higher returner% than the early WD and control groups. CONCLUSIONS MScanFit can monitor neuromuscular dysfunction during WD. SIs revealed excitability changes in DS.
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Affiliation(s)
- Ozlem Kesim-Sahin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Nermin Gorkem Sirin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Bahar Erbas
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.,Department of Pharmacology, Istanbul Bilim University, Istanbul, Turkey
| | - Tugrul Artug
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.,Department of Electrical and Electronics Engineering, Istanbul Arel University, Istanbul, Turkey
| | - Emel Oguz-Akarsu
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Elif Kocasoy-Orhan
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Mehmet Baris Baslo
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Nermin Mammadova
- Department of Reconstructive and Plastic Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ufuk Emekli
- Department of Reconstructive and Plastic Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ali Emre Oge
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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Mole AJ, Bell S, Thomson AK, Dissanayake KN, Ribchester RR, Murray LM. Synaptic withdrawal following nerve injury is influenced by postnatal maturity, muscle-specific properties, and the presence of underlying pathology in mice. J Anat 2020; 237:263-274. [PMID: 32311115 PMCID: PMC7369188 DOI: 10.1111/joa.13187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/30/2020] [Accepted: 03/02/2020] [Indexed: 01/13/2023] Open
Abstract
Axonal and synaptic degeneration occur following nerve injury and during disease. Traumatic nerve injury results in rapid fragmentation of the distal axon and loss of synaptic terminals, in a process known as Wallerian degeneration (WD). Identifying and understanding factors that influence the rate of WD is of significant biological and clinical importance, as it will facilitate understanding of the mechanisms of neurodegeneration and identification of novel therapeutic targets. Here, we investigate levels of synaptic loss following nerve injury under a range of conditions, including during postnatal development, in a range of anatomically distinct muscles and in a mouse model of motor neuron disease. By utilising an ex vivo model of nerve injury, we show that synaptic withdrawal is slower during early postnatal development. Significantly more neuromuscular junctions remained fully innervated in the cranial nerve/muscle preparations analysed at P15 than at P25. Furthermore, we demonstrate variability in the level of synaptic withdrawal in response to injury in different muscles, with retraction being slower in abdominal preparations than in cranial muscles across all time points analysed. Importantly, differences between the cranial and thoracoabdominal musculature seen here are not consistent with differences in muscle vulnerability that have been previously reported in mouse models of the childhood motor neuron disease, spinal muscular atrophy (SMA), caused by depletion of survival motor neuron protein (Smn). To further investigate the relationship between synaptic degeneration in SMA and WD, we induced WD in preparations from the Smn2B/− mouse model of SMA. In a disease‐resistant muscle (rostral band of levator auris longus), where there is minimal denervation, there was no change in the level of synaptic loss, which suggests that the process of synaptic withdrawal following injury is Smn‐independent. However, in a muscle with ongoing degeneration (transvs. abdominis), the level of synaptic loss significantly increased, with the percentage of denervated endplates increasing by 33% following injury, compared to disease alone. We therefore conclude that the presence of a die‐back can accelerate synaptic loss after injury in Smn2B/− mice.
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Affiliation(s)
- Alannah J Mole
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Sarah Bell
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Alison K Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Kosala N Dissanayake
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Richard R Ribchester
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
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Azzarito M, Seif M, Kyathanahally S, Curt A, Freund P. Tracking the neurodegenerative gradient after spinal cord injury. NEUROIMAGE-CLINICAL 2020; 26:102221. [PMID: 32145681 PMCID: PMC7058923 DOI: 10.1016/j.nicl.2020.102221] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/21/2020] [Accepted: 02/17/2020] [Indexed: 01/12/2023]
Abstract
OBJECTIVE To quantify neurodegenerative changes along the cervical spinal cord rostral to a spinal cord injury (SCI) by means of quantitative MRI (qMRI) and to determine its relationship with clinical impairment. METHODS Thirty chronic SCI patients (15 tetraplegics and 15 paraplegics) and 23 healthy controls underwent a high-resolution T1-weighted and myelin-sensitive magnetization transfer (MT) MRI. We assessed macro- and microstructural changes along the cervical cord from levels C1 to C4, calculating cross-sectional spinal cord area, its anterior-posterior and left-right width and myelin content (i.e. MT). Regression analysis determined associations between qMRI parameters and clinical impairment. RESULTS In SCI patients, cord area decreased by 2.67 mm2 (p = 0.004) and left-right width decreased by 0.35 mm (p = 0.002) per cervical cord level in the caudal direction when compared to the healthy controls. This gradient of neurodegeneration was greater in tetraplegic than paraplegics in the cross-sectional cervical cord area (by 3.28 mm2, p = 0.011), left-right width (by 0.36 mm, p = 0.03), and mean cord MT (by 0.13%, p = 0.04), but independant of lesion severity (p > 0.05). Higher lesion level was associated with greater magnitudes of neurodegeneration. Greater loss in myelin content in the dorsal columns and spinothalamic tract was associated with worse light touch (p = 0.016) and pin prick score (p = 0.024), respectively. CONCLUSIONS A gradient of neurodegeneration is evident in the cervical cord remote from a SCI. Tract-specific associations with appropriate clinical outcomes highlight that remote neurodegenerative changes are clinically eloquent. Monitoring the neurodegenerative gradient could be used to track treatment effects of regenerative and neuroprotective agents, both in trials targeting cervical and thoracic SCI patients.
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Affiliation(s)
- Michela Azzarito
- Spinal Cord Injury Center Balgrist, University Hospital, Zurich, Switzerland.
| | - Maryam Seif
- Spinal Cord Injury Center Balgrist, University Hospital, Zurich, Switzerland.
| | | | - Armin Curt
- Spinal Cord Injury Center Balgrist, University Hospital, Zurich, Switzerland.
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, University Hospital, Zurich, Switzerland; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, United Kingdom; Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
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cADPR is a gene dosage-sensitive biomarker of SARM1 activity in healthy, compromised, and degenerating axons. Exp Neurol 2020; 329:113252. [PMID: 32087251 DOI: 10.1016/j.expneurol.2020.113252] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 02/03/2023]
Abstract
SARM1 is the central executioner of pathological axon degeneration, promoting axonal demise in response to axotomy, traumatic brain injury, and neurotoxic chemotherapeutics that induce peripheral neuropathy. SARM1 is an injury-activated NAD+ cleavage enzyme, and this NADase activity is required for the pro-degenerative function of SARM1. At present, SARM1 function is assayed by either analysis of axonal loss, which is far downstream of SARM1 enzymatic activity, or via NAD+ levels, which are regulated by many competing pathways. Here we explored the utility of measuring cADPR, a product of SARM1-dependent cleavage of NAD+, as an in cell and in vivo biomarker of SARM1 enzymatic activity. We find that SARM1 is a major producer of cADPR in cultured dorsal root ganglion (DRG) neurons, sciatic nerve, and brain, demonstrating that SARM1 has basal activity in the absence of injury. Following injury, there is a dramatic SARM1-dependent increase in the levels of axonal cADPR that precedes morphological axon degeneration. In vivo, there is also a rapid and large injury-stimulated increase in cADPR in sciatic and optic nerves. The increase in cADPR after injury is proportional to SARM1 gene dosage, suggesting that SARM1 activity is the prime regulator of cADPR levels. The role of cADPR as an important calcium mobilizing agent prompted exploration of its functional contribution to axon degeneration. We used multiple bacterial and mammalian engineered enzymes to manipulate cADPR levels in neurons but found no changes in the time course of axonal degeneration, suggesting that cADPR is unlikely to be an important contributor to the degenerative mechanism. Using cADPR as a SARM1 biomarker, we find that SARM1 can be partially activated by a diverse array of mitochondrial toxins administered at doses that do not induce axon degeneration. Hence, the subcritical activation of SARM1 induced by mitochondrial dysfunction may contribute to the axonal vulnerability common to many neurodegenerative diseases. Finally, we assay levels of both nerve cADPR and plasma neurofilament light chain (NfL) following nerve injury in vivo, and demonstrate that both biomarkers are excellent readouts of SARM1 activity, with cADPR reporting the early molecular changes in the nerve and NfL reporting subsequent axonal breakdown. The identification and characterization of cADPR as a SARM1 biomarker will help identify neurodegenerative diseases in which SARM1 contributes to axonal loss and expedite target validation studies of SARM1-directed therapeutics.
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Li R, Li D, Wu C, Ye L, Wu Y, Yuan Y, Yang S, Xie L, Mao Y, Jiang T, Li Y, Wang J, Zhang H, Li X, Xiao J. Nerve growth factor activates autophagy in Schwann cells to enhance myelin debris clearance and to expedite nerve regeneration. Theranostics 2020; 10:1649-1677. [PMID: 32042328 PMCID: PMC6993217 DOI: 10.7150/thno.40919] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 10/27/2019] [Indexed: 12/12/2022] Open
Abstract
Rationale: Autophagy in Schwann cells (SCs) is crucial for myelin debris degradation and clearance following peripheral nerve injury (PNI). Nerve growth factor (NGF) plays an important role in reconstructing peripheral nerve fibers and promoting axonal regeneration. However, it remains unclear if NGF effect in enhancing nerve regeneration is mediated through autophagic clearance of myelin debris in SCs. Methods: In vivo, free NGF solution plus with/without pharmacological inhibitors were administered to a rat sciatic nerve crush injury model. In vitro, the primary Schwann cells (SCs) and its cell line were cultured in normal medium containing NGF, their capable of swallowing or clearing degenerated myelin was evaluated through supplement of homogenized myelin fractions. Results: Administration of exogenous NGF could activate autophagy in dedifferentiated SCs, accelerate myelin debris clearance and phagocytosis, as well as promote axon and myelin regeneration at early stage of PNI. These NGF effects were effectively blocked by autophagy inhibitors. In addition, inhibition of the p75 kD neurotrophin receptor (p75NTR) signal or inactivation of the AMP-activated protein kinase (AMPK) also inhibited the NGF effect as well. Conclusions: NGF effect on promoting early nerve regeneration is closely associated with its accelerating autophagic clearance of myelin debris in SCs, which probably regulated by the p75NTR/AMPK/mTOR axis. Our studies thus provide strong support that NGF may serve as a powerful pharmacological therapy for peripheral nerve injuries.
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Chandrasekaran S, Davis J, Bersch I, Goldberg G, Gorgey AS. Electrical stimulation and denervated muscles after spinal cord injury. Neural Regen Res 2020; 15:1397-1407. [PMID: 31997798 PMCID: PMC7059583 DOI: 10.4103/1673-5374.274326] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Spinal cord injury (SCI) population with injury below T10 or injury to the cauda equina region is characterized by denervated muscles, extensive muscle atrophy, infiltration of intramuscular fat and formation of fibrous tissue. These morphological changes may put individuals with SCI at higher risk for developing other diseases such as various cardiovascular diseases, diabetes, obesity and osteoporosis. Currently, there is no available rehabilitation intervention to rescue the muscles or restore muscle size in SCI individuals with lower motor neuron denervation. We, hereby, performed a review of the available evidence that supports the use of electrical stimulation in restoration of denervated muscle following SCI. Long pulse width stimulation (LPWS) technique is an upcoming method of stimulating denervated muscles. Our primary objective is to explore the best stimulation paradigms (stimulation parameters, stimulation technique and stimulation wave) to achieve restoration of the denervated muscle. Stimulation parameters, such as the pulse duration, need to be 100–1000 times longer than in innervated muscles to achieve desirable excitability and contraction. The use of electrical stimulation in animal and human models induces muscle hypertrophy. Findings in animal models indicate that electrical stimulation, with a combination of exercise and pharmacological interventions, have proven to be effective in improving various aspects like relative muscle weight, muscle cross sectional area, number of myelinated regenerated fibers, and restoring some level of muscle function. Human studies have shown similar outcomes, identifying the use of LPWS as an effective strategy in increasing muscle cross sectional area, the size of muscle fibers, and improving muscle function. Therefore, displaying promise is an effective future stimulation intervention. In summary, LPWS is a novel stimulation technique for denervated muscles in humans with SCI. Successful studies on LPWS of denervated muscles will help in translating this stimulation technique to the clinical level as a rehabilitation intervention after SCI.
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Affiliation(s)
| | - John Davis
- Spinal Cord Injury and Disorders, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
| | - Ines Bersch
- Swiss Paraplegic Centre, Nottwil, Switzerland; Institute of Clinical Sciences, Department of Orthopedics at the University of Gothenburg, Gothenburg, Sweden
| | - Gary Goldberg
- Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University; Electrodiagnostic Center, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
| | - Ashraf S Gorgey
- Spinal Cord Injury and Disorders, Hunter Holmes McGuire VA Medical Center; Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University, Richmond, VA, USA
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