1
|
Wu S, Su Y, Wang Y, Wang J, Xu D, Liu Y, Yang K, Gao J, Cui J, Bai W. Region-specific response of central microglial cells to sciatic nerve demyelination through sensory and motor pathways. Histol Histopathol 2024; 39:771-781. [PMID: 38051019 DOI: 10.14670/hh-18-681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Peripheral nerve injury can cause changes in microglial cells on the spinal dorsal and ventral horns. This region-specific response implies that central microglial cells could be activated through both sensory and motor pathways. In order to further determine how peripheral nerve injury activates central microglial cells through neural pathways, the sciatic nerve was selected as the target for neural tract tracing and demyelination. Firstly, we used cholera toxin subunit B (CTB) to map the central sensory and motor territories of the sciatic nerve. Secondly, we applied lysophosphatidylcholine to establish the model of sciatic nerve demyelination and examined the distribution of activated microglial cells via immunofluorescence with ionized calcium-binding adapter molecule 1. It was shown that CTB labeling included the transganglionically labeled sensory afferents and retrogradely labeled somata of motor neurons along the sensory and motor pathways of the sciatic nerve ipsilateral to the injection, in which sensory afferents terminated on the gracile nucleus, Clarke's nucleus, and spinal dorsal horn, while motor neurons located on the spinal ventral horn. Consistently, after sciatic nerve demyelination, the activated microglial cells were observed in the same territories as CTB-labeling, showing shortened processes and enlarged cell bodies. These results support the idea that central microglia might be activated by signals from the demyelinated sciatic nerve through both sensory and motor pathways.
Collapse
Affiliation(s)
- Shuang Wu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Yuxin Su
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Yuqing Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Jia Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Dongsheng Xu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Yihan Liu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Kunwu Yang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Junhong Gao
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China
| | - Jingjing Cui
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China.
| | - Wanzhu Bai
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, PR China.
| |
Collapse
|
2
|
da Silva NS, Lombardi J, Kirchhoff F, Ferreira RS, Barraviera B, de Oliveira ALR, Cartarozzi LP. Effects of local and systemic treatment with human natural killer-1 mimetic peptide (HNK-1) after ventral root avulsion and reimplantation in mice. J Venom Anim Toxins Incl Trop Dis 2024; 30:e20230065. [PMID: 38770186 PMCID: PMC11105159 DOI: 10.1590/1678-9199-jvatitd-2023-0065] [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: 08/28/2023] [Accepted: 04/01/2024] [Indexed: 05/22/2024] Open
Abstract
Background Spinal ventral root injuries generate significant motoneuron degeneration, which hinders full functional recovery. The poor prognosis of functional recovery can be attributed to the use or combination of different therapeutic approaches. Several molecules have been screened as potential treatments in combination with surgical reimplantation of the avulsed roots, the gold standard approach for such injuries. Among the studied molecules, human natural killer-1 (HNK-1) stands out as it is related to the stimulation of motor axon outgrowth. Therefore, we aimed to comparatively investigate the effects of local administration of an HNK-1 mimetic peptide (mp-HNK-1) and systemic treatment with ursolic acid (UA), another HNK-1 mimetic, after ventral root avulsion and reimplantation with heterologous fibrin biopolymer (HFB). Methods Female mice of the isogenic strain C57BL/6JUnib were divided into five experimental groups: Avulsion, Reimplantation, mp-HNK-1 (in situ), and UA (systemic treatment). Mice were evaluated 2 and 12 weeks after surgery. Functional assessment was performed every four days using the Catwalk platform. Neuronal survival was analyzed by cytochemistry, and glial reactions and synaptic coverage were evaluated by immunofluorescence. Results Treatment with UA elicited long-term neuroprotection, accompanied by a decrease in microglial reactions, and reactive astrogliosis. The neuroprotective effects of UA were preceded by increased glutamatergic and GABAergic inputs in the ventral spinal cord two weeks after injury. However, a single application of mp-HNK-1 had no significant effects. Functional analysis showed that UA treatment led to an improvement in motor and sensory recovery. Conclusion Overall, the results indicate that UA is neuroprotective, acting on glial cells and synaptic maintenance, and the combination of these findings led to a better functional recovery.
Collapse
Affiliation(s)
- Natalia Scanavachia da Silva
- Department of Structural and Functional Biology, Laboratory of Nerve Regeneration, Institute of Biology, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Julia Lombardi
- Department of Structural and Functional Biology, Laboratory of Nerve Regeneration, Institute of Biology, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
- Center for Gender-specific Biology and Medicine (CGBM), University of Saarland, Homburg, Germany
| | - Rui Seabra Ferreira
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Benedito Barraviera
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Alexandre Leite Rodrigues de Oliveira
- Department of Structural and Functional Biology, Laboratory of Nerve Regeneration, Institute of Biology, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Luciana Politti Cartarozzi
- Department of Structural and Functional Biology, Laboratory of Nerve Regeneration, Institute of Biology, University of Campinas (Unicamp), Campinas, SP, Brazil
| |
Collapse
|
3
|
Alvites R, Lopes B, Coelho A, Maurício AC. Peripheral nerve regeneration: a challenge far from being overcome. Regen Med 2024; 19:155-159. [PMID: 37786972 DOI: 10.2217/rme-2023-0072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023] Open
Affiliation(s)
- Rui Alvites
- Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto (ICETA), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
- Departamento de Clínicas Veterinárias, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Rua de Jorge Viterbo Ferreira, No. 228, 4050-313 Porto, Portugal
- Associate Laboratory for Animal & Veterinary Science (AL4AnimalS), 1300-477 Lisboa, Portugal
- Instituto Universitário de Ciências da Saúde (CESPU), Avenida Central de Gandra 1317, Gandra, 4585-116 Paredes, Portugal
| | - Bruna Lopes
- Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto (ICETA), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
- Departamento de Clínicas Veterinárias, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Rua de Jorge Viterbo Ferreira, No. 228, 4050-313 Porto, Portugal
- Associate Laboratory for Animal & Veterinary Science (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - André Coelho
- Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto (ICETA), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
- Departamento de Clínicas Veterinárias, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Rua de Jorge Viterbo Ferreira, No. 228, 4050-313 Porto, Portugal
- Associate Laboratory for Animal & Veterinary Science (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Ana Colette Maurício
- Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto (ICETA), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
- Departamento de Clínicas Veterinárias, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Rua de Jorge Viterbo Ferreira, No. 228, 4050-313 Porto, Portugal
- Associate Laboratory for Animal & Veterinary Science (AL4AnimalS), 1300-477 Lisboa, Portugal
| |
Collapse
|
4
|
Rotterman TM, Haley-Johnson Z, Pottorf TS, Chopra T, Chang E, Zhang S, McCallum WM, Fisher S, Franklin H, Alvarez M, Cope TC, Alvarez FJ. Modulation of central synapse remodeling after remote peripheral injuries by the CCL2-CCR2 axis and microglia. Cell Rep 2024; 43:113776. [PMID: 38367237 PMCID: PMC10947500 DOI: 10.1016/j.celrep.2024.113776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 12/19/2023] [Accepted: 01/25/2024] [Indexed: 02/19/2024] Open
Abstract
Microglia-mediated synaptic plasticity after CNS injury varies depending on injury severity, but the mechanisms that adjust synaptic plasticity according to injury differences are largely unknown. This study investigates differential actions of microglia on essential spinal motor synaptic circuits following different kinds of nerve injuries. Following nerve transection, microglia and C-C chemokine receptor type 2 signaling permanently remove Ia axons and synapses from the ventral horn, degrading proprioceptive feedback during motor actions and abolishing stretch reflexes. However, Ia synapses and reflexes recover after milder injuries (nerve crush). These different outcomes are related to the length of microglia activation, being longer after nerve cuts, with slower motor-axon regeneration and extended expression of colony-stimulating factor type 1 in injured motoneurons. Prolonged microglia activation induces CCL2 expression, and Ia synapses recover after ccl2 is deleted from microglia. Thus, microglia Ia synapse removal requires the induction of specific microglia phenotypes modulated by nerve regeneration efficiencies. However, synapse preservation was not sufficient to restore the stretch-reflex function.
Collapse
Affiliation(s)
- Travis M Rotterman
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA
| | - Zoë Haley-Johnson
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Tana S Pottorf
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Tavishi Chopra
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Ethan Chang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA
| | - Shannon Zhang
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | | | - Sarah Fisher
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Haley Franklin
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; The Alabama College of Osteopathic Medicine, Dothan, AL 36301, USA
| | - Myriam Alvarez
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Timothy C Cope
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA; W.H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | |
Collapse
|
5
|
Asghari Adib E, Shadrach JL, Reilly-Jankowiak L, Dwivedi MK, Rogers AE, Shahzad S, Passino R, Giger RJ, Pierchala BA, Collins CA. DLK signaling in axotomized neurons triggers complement activation and loss of upstream synapses. Cell Rep 2024; 43:113801. [PMID: 38363678 PMCID: PMC11088462 DOI: 10.1016/j.celrep.2024.113801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/27/2023] [Accepted: 01/31/2024] [Indexed: 02/18/2024] Open
Abstract
Axotomized spinal motoneurons (MNs) lose presynaptic inputs following peripheral nerve injury; however, the cellular mechanisms that lead to this form of synapse loss are currently unknown. Here, we delineate a critical role for neuronal kinase dual leucine zipper kinase (DLK)/MAP3K12, which becomes activated in axotomized neurons. Studies with conditional knockout mice indicate that DLK signaling activation in injured MNs triggers the induction of phagocytic microglia and synapse loss. Aspects of the DLK-regulated response include expression of C1q first from the axotomized MN and then later in surrounding microglia, which subsequently phagocytose presynaptic components of upstream synapses. Pharmacological ablation of microglia inhibits the loss of cholinergic C boutons from axotomized MNs. Together, the observations implicate a neuronal mechanism, governed by the DLK, in the induction of inflammation and the removal of synapses.
Collapse
Affiliation(s)
- Elham Asghari Adib
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Jennifer L Shadrach
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA
| | | | - Manish K Dwivedi
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Abigail E Rogers
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Shameena Shahzad
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Brian A Pierchala
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA; Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, 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.
| |
Collapse
|
6
|
Abstract
Vascular endothelial growth factor (VEGF) is well known for its angiogenic activity, but recent evidence has revealed a neuroprotective action of this factor on injured or diseased neurons. In the present review, we summarize the most relevant findings that have contributed to establish a link between VEGF deficiency and neuronal degeneration. At issue, 1) mutant mice with reduced levels of VEGF show adult-onset muscle weakness and motoneuron degeneration resembling amyotrophic lateral sclerosis (ALS), 2) administration of VEGF to different animal models of motoneuron degeneration improves motor performance and ameliorates motoneuronal degeneration, and 3) there is an association between low plasmatic levels of VEGF and human ALS. Altogether, the results presented in this review highlight VEGF as an essential motoneuron neurotrophic factor endowed with promising therapeutic potential for the treatment of motoneuron disorders.
Collapse
Affiliation(s)
- Paula M Calvo
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Rosendo G Hernández
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Angel M Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Rosa R de la Cruz
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| |
Collapse
|
7
|
Kim S, An S, Lee J, Jeong Y, You C, Kim H, Bae J, Yun C, Ryu D, Bae G, Kang J. Cdon ablation in motor neurons causes age-related motor neuron degeneration and impaired sciatic nerve repair. J Cachexia Sarcopenia Muscle 2023; 14:2239-2252. [PMID: 37559423 PMCID: PMC10570074 DOI: 10.1002/jcsm.13308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 05/19/2023] [Accepted: 07/11/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND The functional deterioration and loss of motor neurons are tightly associated with degenerative motor neuron diseases and aging-related muscle wasting. Motor neuron diseases or aging-related muscle wasting in turn contribute to increased risk of adverse health outcomes in the elderly. Cdon (cell adhesion molecule-downregulated oncogene) belongs to the immunoglobulin superfamily of cell adhesion molecule and plays essential roles in multiple signalling pathways, including sonic hedgehog (Shh), netrin, and cadherin-mediated signalling. Cdon as a Shh coreceptor plays a critical role in motor neuron specification during embryonic development. However, its role in adult motor neuron function is unknown. METHODS Hb9-Cre recombinase-driven motor neuron-specific Cdon deficient mice (mnKO) and a compound mutant mice (mnKO::SOD1G93A ) were generated to investigate the role of Cdon in motor neuron degeneration. Motor neuron regeneration was examined by using a sciatic nerve crush injury model. To investigate the phenotype, physical activity, compound muscle action potential, immunostaining, and transmission electron microscopy were carried out. In the mechanism study, RNA sequencing and RNA/protein analyses were employed. RESULTS Mice lacking Cdon in motor neurons exhibited middle age onset lethality and aging-related decline in motor function. In the sciatic nerve crush injury model, mnKO mice exhibited an impairment in motor function recovery evident by prolonged compound muscle action potential duration (4.63 ± 0.35 vs. 3.93 ± 0.22 s for f/f, P < 0.01) and physical activity. Consistently, neuromuscular junctions of mnKO muscles were incompletely occupied (49.79 ± 5.74 vs. 79.39 ± 3.77% fully occupied neuromuscular junctions for f/f, P < 0.0001), suggesting an impaired reinnervation. The transmission electron microscopy analysis revealed that mnKO sciatic nerves had smaller axon diameter (0.88 ± 0.13 vs. 1.43 ± 0.48 μm for f/f, P < 0.0001) and myelination defects. RNA sequencing of mnKO lumbar spinal cords showed alteration in genes related to neurogenesis, inflammation and cell death. Among the altered genes, ErbB4 and FgfR expressions were significantly altered in mnKO as well as in Cdon-depleted NSC34 motor neuron cells. Consistently, Cdon-depleted NSC34 cells exhibited elevated levels of cleaved Caspase3 and γH2AX proteins, as well as Bax transcription. Cdon-depleted NSC34 cells also exhibited impaired activation of Akt in response to neuregulin-1 (NRG1) treatment. CONCLUSIONS Our current data demonstrate the functional importance of Cdon in motor neuron function and nerve repair. Cdon ablation causes alterations in neurotrophin signalling that leads to motor neuron degeneration.
Collapse
Affiliation(s)
- Sunghee Kim
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| | - Subin An
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| | - Jinwoo Lee
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Research Institute of Animuscure INCSuwonSouth Korea
| | - Yideul Jeong
- Research Institute of Animuscure INCSuwonSouth Korea
| | - Chang‐Lim You
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| | - Hyebeen Kim
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| | - Ju‐Hyeon Bae
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| | - Chae‐Eun Yun
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| | - Dongryul Ryu
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
| | - Gyu‐Un Bae
- College of PharmacySookmyung Women's UniversitySeoulSouth Korea
| | - Jong‐Sun Kang
- Department of Molecular Cell BiologySungkyunkwan University School of MedicineSuwonSouth Korea
- Single Cell Network Research CenterSungkyunkwan University School of MedicineSuwonSouth Korea
| |
Collapse
|
8
|
Kandhavivorn W, Glaß H, Herrmannsdörfer T, Böckers TM, Uhlarz M, Gronemann J, Funk RHW, Pietzsch J, Pal A, Hermann A. Restoring Axonal Organelle Motility and Regeneration in Cultured FUS-ALS Motoneurons through Magnetic Field Stimulation Suggests an Alternative Therapeutic Approach. Cells 2023; 12:1502. [PMID: 37296623 PMCID: PMC10252208 DOI: 10.3390/cells12111502] [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: 03/09/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating motoneuron disease characterized by sustained loss of neuromuscular junctions, degenerating corticospinal motoneurons and rapidly progressing muscle paralysis. Motoneurons have unique features, essentially a highly polarized, lengthy architecture of axons, posing a considerable challenge for maintaining long-range trafficking routes for organelles, cargo, mRNA and secretion with a high energy effort to serve crucial neuronal functions. Impaired intracellular pathways implicated in ALS pathology comprise RNA metabolism, cytoplasmic protein aggregation, cytoskeletal integrity for organelle trafficking and maintenance of mitochondrial morphology and function, cumulatively leading to neurodegeneration. Current drug treatments only have marginal effects on survival, thereby calling for alternative ALS therapies. Exposure to magnetic fields, e.g., transcranial magnetic stimulations (TMS) on the central nervous system (CNS), has been broadly explored over the past 20 years to investigate and improve physical and mental activities through stimulated excitability as well as neuronal plasticity. However, studies of magnetic treatments on the peripheral nervous system are still scarce. Thus, we investigated the therapeutic potential of low frequency alternating current magnetic fields on cultured spinal motoneurons derived from induced pluripotent stem cells of FUS-ALS patients and healthy persons. We report a remarkable restoration induced by magnetic stimulation on axonal trafficking of mitochondria and lysosomes and axonal regenerative sprouting after axotomy in FUS-ALS in vitro without obvious harmful effects on diseased and healthy neurons. These beneficial effects seem to derive from improved microtubule integrity. Thus, our study suggests the therapeutic potential of magnetic stimulations in ALS, which awaits further exploration and validation in future long-term in vivo studies.
Collapse
Affiliation(s)
- Wonphorn Kandhavivorn
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
- Institute of Anatomy, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Hannes Glaß
- Division for Neurodegenerative Diseases, Department of Neurology, Technische Universität Dresden, D-01307 Dresden, Germany;
- Translational Neurodegeneration Section “Albrecht Kossel”, Department of Neurology, University Medical Center Rostock, University of Rostock, D-18147 Rostock, Germany
| | - Thomas Herrmannsdörfer
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
| | - Tobias M. Böckers
- Institute of Anatomy and Cell Biology, University of Ulm, D-89081 Ulm, Germany;
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Ulm, D-89081 Ulm, Germany
| | - Marc Uhlarz
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
| | - Jonas Gronemann
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
| | - Richard H. W. Funk
- Institute of Anatomy, Technische Universität Dresden, D-01307 Dresden, Germany
- Dresden International University, D-01067 Dresden, Germany
| | - Jens Pietzsch
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany
- Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Arun Pal
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
- Division for Neurodegenerative Diseases, Department of Neurology, Technische Universität Dresden, D-01307 Dresden, Germany;
| | - Andreas Hermann
- Division for Neurodegenerative Diseases, Department of Neurology, Technische Universität Dresden, D-01307 Dresden, Germany;
- Translational Neurodegeneration Section “Albrecht Kossel”, Department of Neurology, University Medical Center Rostock, University of Rostock, D-18147 Rostock, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Rostock/Greifswald, D-18147 Rostock, Germany
- Center for Transdisciplinary Neurosciences Rostock (CTNR), University Medical Center Rostock, University of Rostock, D-18147 Rostock, Germany
| |
Collapse
|
9
|
Cheung DL, Toda T, Narushima M, Eto K, Takayama C, Ooba T, Wake H, Moorhouse AJ, Nabekura J. KCC2 downregulation after sciatic nerve injury enhances motor function recovery. Sci Rep 2023; 13:7871. [PMID: 37188694 DOI: 10.1038/s41598-023-34701-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 05/05/2023] [Indexed: 05/17/2023] Open
Abstract
Injury to mature neurons induces downregulated KCC2 expression and activity, resulting in elevated intracellular [Cl-] and depolarized GABAergic signaling. This phenotype mirrors immature neurons wherein GABA-evoked depolarizations facilitate neuronal circuit maturation. Thus, injury-induced KCC2 downregulation is broadly speculated to similarly facilitate neuronal circuit repair. We test this hypothesis in spinal cord motoneurons injured by sciatic nerve crush, using transgenic (CaMKII-KCC2) mice wherein conditional CaMKIIα promoter-KCC2 expression coupling selectively prevents injury-induced KCC2 downregulation. We demonstrate, via an accelerating rotarod assay, impaired motor function recovery in CaMKII-KCC2 mice relative to wild-type mice. Across both cohorts, we observe similar motoneuron survival and re-innervation rates, but differing post-injury reorganization patterns of synaptic input to motoneuron somas-for wild-type, both VGLUT1-positive (excitatory) and GAD67-positive (inhibitory) terminal counts decrease; for CaMKII-KCC2, only VGLUT1-positive terminal counts decrease. Finally, we recapitulate the impaired motor function recovery of CaMKII-KCC2 mice in wild-type mice by administering local spinal cord injections of bicuculline (GABAA receptor blockade) or bumetanide (lowers intracellular [Cl-] by NKCC1 blockade) during the early post-injury period. Thus, our results provide direct evidence that injury-induced KCC2 downregulation enhances motor function recovery and suggest an underlying mechanism of depolarizing GABAergic signaling driving adaptive reconfiguration of presynaptic GABAergic input.
Collapse
Affiliation(s)
- Dennis Lawrence Cheung
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Takuya Toda
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Madoka Narushima
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Kei Eto
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, Japan
| | | | - Tatsuko Ooba
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Hiroaki Wake
- Division of Multicellular Circuit Dynamics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Graduate School of Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Andrew John Moorhouse
- School of Biomedical Sciences, UNSW Sydney (The University of New South Wales), Sydney, New South Wales, Australia
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.
- Graduate School of Medicine, Nagoya University, Nagoya, Aichi, Japan.
- School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, Japan.
| |
Collapse
|
10
|
Sleijser-Koehorst MLS, Koop MA, Coppieters MW, Lutke Schipholt IJ, Radisic N, Hooijmans CR, Scholten-Peeters GGM. The effects of aerobic exercise on neuroimmune responses in animals with traumatic peripheral nerve injury: a systematic review with meta-analyses. J Neuroinflammation 2023; 20:104. [PMID: 37138291 PMCID: PMC10155410 DOI: 10.1186/s12974-023-02777-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
BACKGROUND Increasing pre-clinical evidence suggests that aerobic exercise positively modulates neuroimmune responses following traumatic nerve injury. However, meta-analyses on neuroimmune outcomes are currently still lacking. This study aimed to synthesize the pre-clinical literature on the effects of aerobic exercise on neuroimmune responses following peripheral nerve injury. METHODS MEDLINE (via Pubmed), EMBASE and Web of Science were searched. Controlled experimental studies on the effect of aerobic exercise on neuroimmune responses in animals with a traumatically induced peripheral neuropathy were considered. Study selection, risk of bias assessment and data extraction were performed independently by two reviewers. Results were analyzed using random effects models and reported as standardized mean differences. Outcome measures were reported per anatomical location and per class of neuro-immune substance. RESULTS The literature search resulted in 14,590 records. Forty studies were included, reporting 139 comparisons of neuroimmune responses at various anatomical locations. All studies had an unclear risk of bias. Compared to non-exercised animals, meta-analyses showed the following main differences in exercised animals: (1) in the affected nerve, tumor necrosis factor-α (TNF-α) levels were lower (p = 0.003), while insulin-like growth factor-1 (IGF-1) (p < 0.001) and Growth Associated Protein 43 (GAP43) (p = 0.01) levels were higher; (2) At the dorsal root ganglia, brain-derived neurotrophic factor (BDNF)/BDNF mRNA levels (p = 0.004) and nerve growth factor (NGF)/NGF mRNA (p < 0.05) levels were lower; (3) in the spinal cord, BDNF levels (p = 0.006) were lower; at the dorsal horn, microglia (p < 0.001) and astrocyte (p = 0.005) marker levels were lower; at the ventral horn, astrocyte marker levels (p < 0.001) were higher, and several outcomes related to synaptic stripping were favorably altered; (4) brainstem 5-HT2A receptor levels were higher (p = 0.001); (5) in muscles, BDNF levels (p < 0.001) were higher and TNF-α levels lower (p < 0.05); (6) no significant differences were found for systemic neuroimmune responses in blood or serum. CONCLUSION This review revealed widespread positive modulatory effects of aerobic exercise on neuroimmune responses following traumatic peripheral nerve injury. These changes are in line with a beneficial influence on pro-inflammatory processes and increased anti-inflammatory responses. Given the small sample sizes and the unclear risk of bias of the studies, results should be interpreted with caution.
Collapse
Affiliation(s)
- Marije L S Sleijser-Koehorst
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences-Program Musculoskeletal Health, Vrije Universiteit Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands.
| | - Meghan A Koop
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences-Program Musculoskeletal Health, Vrije Universiteit Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
| | - Michel W Coppieters
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences-Program Musculoskeletal Health, Vrije Universiteit Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
- Menzies Health Institute Queensland, Griffith University, Brisbane and Gold Coast, Australia
- School of Health Sciences and Social Work, Griffith University, Brisbane and Gold Coast, Australia
| | - Ivo J Lutke Schipholt
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences-Program Musculoskeletal Health, Vrije Universiteit Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
- Department of Clinical Chemistry, Laboratory Medical Immunology, Amsterdam University Medical Centre, Location VUmc, Amsterdam, The Netherlands
| | - Nemanja Radisic
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences-Program Musculoskeletal Health, Vrije Universiteit Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
| | - Carlijn R Hooijmans
- Department of Anesthesiology, Pain and Palliative Care (Meta Research Team), Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Gwendolyne G M Scholten-Peeters
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences-Program Musculoskeletal Health, Vrije Universiteit Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands.
| |
Collapse
|
11
|
Lee JM, Choi YJ, Yoo MC, Yeo SG. Central Facial Nervous System Biomolecules Involved in Peripheral Facial Nerve Injury Responses and Potential Therapeutic Strategies. Antioxidants (Basel) 2023; 12:antiox12051036. [PMID: 37237902 DOI: 10.3390/antiox12051036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/20/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
Peripheral facial nerve injury leads to changes in the expression of various neuroactive substances that affect nerve cell damage, survival, growth, and regeneration. In the case of peripheral facial nerve damage, the injury directly affects the peripheral nerves and induces changes in the central nervous system (CNS) through various factors, but the substances involved in these changes in the CNS are not well understood. The objective of this review is to investigate the biomolecules involved in peripheral facial nerve damage so as to gain insight into the mechanisms and limitations of targeting the CNS after such damage and identify potential facial nerve treatment strategies. To this end, we searched PubMed using keywords and exclusion criteria and selected 29 eligible experimental studies. Our analysis summarizes basic experimental studies on changes in the CNS following peripheral facial nerve damage, focusing on biomolecules that increase or decrease in the CNS and/or those involved in the damage, and reviews various approaches for treating facial nerve injury. By establishing the biomolecules in the CNS that change after peripheral nerve damage, we can expect to identify factors that play an important role in functional recovery from facial nerve damage. Accordingly, this review could represent a significant step toward developing treatment strategies for peripheral facial palsy.
Collapse
Affiliation(s)
- Jae-Min Lee
- Department of Otorhinolaryngology, Head & Neck Surgery, College of Medicine, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea
| | - You Jung Choi
- Department of Otorhinolaryngology, Head & Neck Surgery, College of Medicine, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea
| | - Myung Chul Yoo
- Department of Physical Medicine & Rehabilitation, College of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Seung Geun Yeo
- Department of Otorhinolaryngology, Head & Neck Surgery, College of Medicine, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea
| |
Collapse
|
12
|
Jin MY, Weaver TE, Farris A, Gupta M, Abd-Elsayed A. Neuromodulation for Peripheral Nerve Regeneration: Systematic Review of Mechanisms and In Vivo Highlights. Biomedicines 2023; 11:biomedicines11041145. [PMID: 37189763 DOI: 10.3390/biomedicines11041145] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/24/2023] [Accepted: 04/07/2023] [Indexed: 05/17/2023] Open
Abstract
While denervation can occur with aging, peripheral nerve injuries are debilitating and often leads to a loss of function and neuropathic pain. Although injured peripheral nerves can regenerate and reinnervate their targets, this process is slow and directionless. There is some evidence supporting the use of neuromodulation to enhance the regeneration of peripheral nerves. This systematic review reported on the underlying mechanisms that allow neuromodulation to aid peripheral nerve regeneration and highlighted important in vivo studies that demonstrate its efficacy. Studies were identified from PubMed (inception through September 2022) and the results were synthesized qualitatively. Included studies were required to contain content related to peripheral nerve regeneration and some form of neuromodulation. Studies reporting in vivo highlights were subject to a risk of bias assessment using the Cochrane Risk of Bias tool. The results of 52 studies indicate that neuromodulation enhances natural peripheral nerve regeneration processes, but still requires other interventions (e.g., conduits) to control the direction of reinnervation. Additional human studies are warranted to verify the applicability of animal studies and to determine how neuromodulation can be optimized for the greatest functional restoration.
Collapse
Affiliation(s)
- Max Y Jin
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Tristan E Weaver
- Department of Anesthesiology, The Ohio State University Wexner Medical Center, Columbus, OH 43214, USA
| | - Adam Farris
- Department of Anesthesiology, The Ohio State University Wexner Medical Center, Columbus, OH 43214, USA
| | - Mayank Gupta
- Kansas Pain Management & Neuroscience Research Center, Overland Park, KS 66210, USA
| | - Alaa Abd-Elsayed
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI 53706, USA
| |
Collapse
|
13
|
Yu L, Liu M, Li F, Wang Q, Wang M, So KF, Qu Y, Zhou L. Celsr2 Knockout Alleviates Inhibitory Synaptic Stripping and Benefits Motoneuron Survival and Axon Regeneration After Branchial Plexus Avulsion. Mol Neurobiol 2023; 60:1884-1900. [PMID: 36593433 PMCID: PMC9984348 DOI: 10.1007/s12035-022-03198-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 12/23/2022] [Indexed: 01/04/2023]
Abstract
Axotomy-induced synaptic stripping modulates survival and axon regeneration of injured motoneurons. Celsr2 is supposed to mediate homophilic interactions of neighboring cells during development, and its role in synaptic stripping remains unknow. In a model of brachial plexus avulsion, Celsr2 knockout improved functional recovery, motoneuron survival, and axon regeneration. Celsr2 was indicated to express in spinal motoneurons, excitatory and inhibitory interneurons, astrocytes, and a subset of oligodendrocytes using Celsr2LacZ mice. Double immunostaining showed that the coverage of inhibitory and excitatory vesicles on injured motoneurons were remarkably reduced after injury, whereas more inhibitory vesicles were maintained in Celsr2-/- mutants than control mice. In the ultrastructure, the density of inhibitory F-boutons on injured motoneurons was higher in Celsr2-/- mutants than controls. Conditional knockout of Celsr2 in astrocytes or oligodendrocytes showed the similar axotomy-induced synaptic withdrawal to the control. RNAseq of injured spinal samples identified 12 MHC I molecules with significant changes between Celsr2-/- and control mice. After injury, expression of MHC I surrounding injured motoneurons was increased, particularly high in Celsr2-/- mutants. In conclusion, Celsr2 knockout enhances MHC I signaling, alleviates inhibitory synaptic stripping cell-autonomously, and contributes to motoneuron survival and regeneration, and Celsr2 is a potential target for neural repair.
Collapse
Affiliation(s)
- Lingtai Yu
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China
| | - Mengfan Liu
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China
| | - Fuxiang Li
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China
| | - Qianghua Wang
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China
| | - Meizhi Wang
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China
| | - Kwok-Fai So
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China.,Department of Neurology and Stroke Center, The First Affiliated Hospital & Clinical Neuroscience Institute of Jinan University, Guangzhou, 510632, People's Republic of China.,Neuroscience and Neurorehabilitation Institute, University of Health and Rehabilitation Sciences, Qingdao, 266071, Shandong, People's Republic of China.,Co-Innovation Center of Neuroregeneration, Nantong University, Jiangsu, People's Republic of China
| | - Yibo Qu
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China.,Co-Innovation Center of Neuroregeneration, Nantong University, Jiangsu, People's Republic of China
| | - Libing Zhou
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, 510632, People's Republic of China. .,Department of Neurology and Stroke Center, The First Affiliated Hospital & Clinical Neuroscience Institute of Jinan University, Guangzhou, 510632, People's Republic of China. .,Neuroscience and Neurorehabilitation Institute, University of Health and Rehabilitation Sciences, Qingdao, 266071, Shandong, People's Republic of China. .,Co-Innovation Center of Neuroregeneration, Nantong University, Jiangsu, People's Republic of China.
| |
Collapse
|
14
|
Paes SM, Castro MVD, Barbosa RM, Politti Cartarozzi L, Coser LDO, Kempe PRG, Decarli MC, Moraes ÂM, Barraviera B, Ferreira Júnior RS, Oliveira ALRD. Human dental pulp stem cell monolayer and spheroid therapy after spinal motor root avulsion in adult rats. Brain Res 2023; 1802:148229. [PMID: 36592804 DOI: 10.1016/j.brainres.2022.148229] [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: 11/02/2022] [Revised: 12/26/2022] [Accepted: 12/29/2022] [Indexed: 12/31/2022]
Abstract
Spinal cord injuries result in severe neurological deficits and neuronal loss, with poor functional recovery. Mesenchymal stem cells have shown promising results; therefore the present objective of this work was to compare motor recovery after treatment with human dental pulp stem cells (hDPSC) cultivated in monolayer (2D) or as spheroids (3D), following avulsion and reimplantation of spinal motor roots in adult rats. Thus, 72 adult female Lewis rats were divided into 4 groups: avulsion (AV); avulsion followed by reimplantation (AR); avulsion associated with reimplant and 2D cell therapy (AR + 2D), and avulsion associated with reimplant and 3D cell therapy (AR + 3D). The application of the cells in 2D and 3D was performed by microsurgery, with subsequent functional assessment using a walking track test (Catwalk system), immunohistochemistry, neuronal survival, and qRT-PCR in 1-, 4-, and 12-weeks post-injury. The animals in the AR + 2D and AR + 3D groups showed the highest neuronal survival rates, and immunofluorescence revealed downregulation of GFAP, and Iba-1, with preservation of synaptophysin, indicating a reduction in glial reactivity, combined with the maintenance of pre-synaptic inputs. There was an increase in anti-inflammatory (IL-4, TGFβ) and a reduction of pro-inflammatory factors (IL-6, TNFα) in animals treated with reimplantation and hDPSC. As for the functional recovery, in all analyzed parameters, the AR + 2D group performed better and was superior to the avulsion alone. Overall, our results indicate that the 2D and 3D cell therapy approaches provide successful immunomodulation and motor recovery, consistent with advanced therapies after spinal cord injury.
Collapse
Affiliation(s)
- Sabrina Moreira Paes
- Laboratory of Nerve Regeneration, Institute of Biology (IB), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Mateus Vidigal de Castro
- Laboratory of Nerve Regeneration, Institute of Biology (IB), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Rafael Maza Barbosa
- Laboratory of Nerve Regeneration, Institute of Biology (IB), State University of Campinas (UNICAMP), Campinas, SP, Brazil; School of Chemical Engineering, University of Campinas, UNICAMP, Av. Albert Einstein, 500, Brazil
| | - Luciana Politti Cartarozzi
- Laboratory of Nerve Regeneration, Institute of Biology (IB), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Lilian de Oliveira Coser
- Laboratory of Nerve Regeneration, Institute of Biology (IB), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Paula Regina Gelinski Kempe
- Laboratory of Nerve Regeneration, Institute of Biology (IB), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Monize Caiado Decarli
- School of Chemical Engineering, University of Campinas, UNICAMP, Av. Albert Einstein, 500, Brazil
| | - Ângela Maria Moraes
- School of Chemical Engineering, University of Campinas, UNICAMP, Av. Albert Einstein, 500, Brazil
| | - Benedito Barraviera
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Rui Seabra Ferreira Júnior
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | | |
Collapse
|
15
|
Pereira CT, Hill EE, Stasyuk A, Parikh N, Dhillon J, Wang A, Li A. Molecular Basis of Surgical Coaptation Techniques in Peripheral Nerve Injuries. J Clin Med 2023; 12:jcm12041555. [PMID: 36836090 PMCID: PMC9966153 DOI: 10.3390/jcm12041555] [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: 01/14/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023] Open
Abstract
Peripheral nerve injuries requiring surgical repair affect over 100,000 individuals in the US annually. Three accepted methods of peripheral repair include end-to-end, end-to-side, and side-to-side neurorrhaphy, each with its own set of indications. While it remains important to understand the specific circumstances in which each method is employed, a deeper understanding of the molecular mechanisms underlying the repair can add to the surgeon's decision-making algorithm when considering each technique, as well as help decide nuances in technique such as the need for making epineurial versus perineurial windows, length and dept of the nerve window, and distance from target muscle. In addition, a thorough knowledge of individual factors that are active in a particular repair can help guide research into adjunct therapies. This paper serves to summarize the similarities and divergences of the three commonly used nerve repair strategies and the scope of molecular mechanisms and signal transduction pathways in nerve regeneration as well as to identify the gaps in knowledge that should be addressed if we are to improve clinical outcomes in our patients.
Collapse
Affiliation(s)
- Clifford T. Pereira
- Department of Surgery, University of California Davis Medical Center, Sacramento, CA 95817, USA
- Division of Plastic Surgery, University of California Davis Medical Center, Sacramento, CA 95817, USA
- Correspondence:
| | - Elise E. Hill
- Department of Surgery, University of California Davis Medical Center, Sacramento, CA 95817, USA
- Department of Surgery, David Grant Medical Center, Travis Air Force Base, Fairfield, CA 94535, USA
| | - Anastasiya Stasyuk
- School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Neil Parikh
- School of Medicine, Boston University, Boston, MA 02118, USA
| | | | - Aijun Wang
- Department of Surgery, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Andrew Li
- Department of Surgery, University of California Davis Medical Center, Sacramento, CA 95817, USA
- Division of Plastic Surgery, University of California Davis Medical Center, Sacramento, CA 95817, USA
| |
Collapse
|
16
|
Andoh M, Koyama R. Microglia and GABA: Diverse functions of microglia beyond GABA-receiving cells. Neurosci Res 2023; 187:52-57. [PMID: 36152917 DOI: 10.1016/j.neures.2022.09.008] [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: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 11/18/2022]
Abstract
Neurotransmitters modulate intracellular signaling not only in neurons but also in glial cells such as astrocytes, which form tripartite synapses, and oligodendrocytes, which produce the myelin sheath on axons. Another major glial cell type, microglia, which are often referred to as brain-resident immune cells, also express receptors for neurotransmitters. Recent studies have mainly focused on excitatory neurotransmitters such as glutamate, and few have examined microglial responses to the inhibitory neurotransmitter GABA. Microglia can also structurally and functionally modulate inhibitory neuronal circuits, but the underlying molecular mechanisms remain largely unknown. Since the well-regulated balance of excitatory/inhibitory (E/I) neurotransmission is believed to be the basis of proper brain function, understanding how microglia regulate and respond to inhibitory neurotransmission will help us deepen our knowledge of neuron-glia interactions. In this review, we discuss the mechanisms by which GABA alters microglial behavior and the possibility that microglia are more than just GABA-receiving cells.
Collapse
Affiliation(s)
- Megumi Andoh
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan; Institute for AI and Beyond, The University of Tokyo, Tokyo 113-0033, Japan.
| |
Collapse
|
17
|
Arbat-Plana A, Bolívar S, Navarro X, Udina E, Alvarez FJ. Massive Loss of Proprioceptive Ia Synapses in Rat Spinal Motoneurons after Nerve Crush Injuries in the Postnatal Period. eNeuro 2023; 10:ENEURO.0436-22.2023. [PMID: 36759186 PMCID: PMC9948128 DOI: 10.1523/eneuro.0436-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/15/2022] [Accepted: 01/26/2023] [Indexed: 02/11/2023] Open
Abstract
Peripheral nerve injuries (PNIs) induce the retraction from the ventral horn of the synaptic collaterals of Ia afferents injured in the nerve, effectively removing Ia synapses from α-motoneurons. The loss of Ia input impairs functional recovery and could explain, in part, better recovery after PNIs with better Ia synaptic preservation. Synaptic losses correlate with injury severity, speed, and efficiency of muscle reinnervation and requires ventral microglia activation. It is unknown whether this plasticity is age dependent. In neonates, axotomized motoneurons and sensory neurons undergo apoptosis, but after postnatal day 10 most survive. The goal of this study was to analyze vesicular glutamate transporter 1 (VGluT1)-labeled Ia synapses (which also include II afferents) after nerve crush in 10 day old rats, a PNI causing little Ia/II synapse loss in adult rats. We confirmed fast and efficient reinnervation of leg muscles; however, a massive number of VGluT1/Ia/II synapses were permanently lost. This synapse loss was similar to that after more severe nerve injuries involving full transection in adults. In adults, disappearance of ventrally directed Ia/II collaterals targeting α-motoneurons was associated with a prolonged microglia reaction and a CCR2 mechanism that included infiltration of CCR2 blood immune cells. By contrast, microgliosis after P10 injuries was fast, resolved in about a week, and there was no evidence of peripheral immune cell infiltration. We conclude that VGluT1/Ia/II synapse loss in young animals differs in mechanism, perhaps associated with higher microglia synaptic pruning activity at this age and results in larger losses after milder nerve injuries.
Collapse
Affiliation(s)
- Ariadna Arbat-Plana
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
- Department of Physiology, Emory University, Atlanta, Georgia 30322
| | - Sara Bolívar
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
- Department of Physiology, Emory University, Atlanta, Georgia 30322
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
| | - Esther Udina
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
| | | |
Collapse
|
18
|
The Time Course of MHC-I Expression in C57BL/6J and A/J Mice Correlates with the Degree of Retrograde Gliosis in the Spinal Cord following Sciatic Nerve Crush. Cells 2022; 11:cells11233710. [PMID: 36496969 PMCID: PMC9740909 DOI: 10.3390/cells11233710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/23/2022] Open
Abstract
The pleiotropic role of the major histocompatibility complex class I (MHC-I) reflects the close association between the nervous and immune systems. In turn, MHC-I upregulation postinjury is associated with a better regenerative outcome in isogenic mice following peripheral nerve damage. In the present work, we compared the time course of neuronal, glial, and sensorimotor recovery (1, 3, 5, 7, and 28 days after lesion—dal) following unilateral sciatic nerve crush in A/J and C57BL/6J mice. The A/J strain showed higher expression of MHC-I (7 dal, ** p < 0.01), Iba-1 (microglial reaction, 7 dal, *** p < 0.001), and GFAP (astrogliosis, 5 dal, * p < 0.05) than the C57BL/6J counterpart. Synaptic coverage (synaptophysin) was equivalent in both strains over time. In addition, mRNA expression of microdissected spinal motoneurons revealed an increase in cytoskeleton-associated molecules (cofilin, shp2, and crmp2, * p < 0.05), but not trkB, in C57BL/6J mice. Gait recovery, studied by the sciatic functional index, was faster in the A/J strain, despite the equivalent results of C57BL/6J at 28 days after injury. A similar recovery was also seen for the nociceptive threshold (von Frey test). Interestingly, when evaluating proprioceptive recovery, C57BL/6J animals showed an enlarged base of support, indicating abnormal ambulation postinjury. Overall, the present results reinforce the role of MHC-I expression in the plasticity of the nervous system following axotomy, which in turn correlates with the variable recovery capacity among strains of mice.
Collapse
|
19
|
Pottorf TS, Rotterman TM, McCallum WM, Haley-Johnson ZA, Alvarez FJ. The Role of Microglia in Neuroinflammation of the Spinal Cord after Peripheral Nerve Injury. Cells 2022; 11:cells11132083. [PMID: 35805167 PMCID: PMC9265514 DOI: 10.3390/cells11132083] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 12/12/2022] Open
Abstract
Peripheral nerve injuries induce a pronounced immune reaction within the spinal cord, largely governed by microglia activation in both the dorsal and ventral horns. The mechanisms of activation and response of microglia are diverse depending on the location within the spinal cord, type, severity, and proximity of injury, as well as the age and species of the organism. Thanks to recent advancements in neuro-immune research techniques, such as single-cell transcriptomics, novel genetic mouse models, and live imaging, a vast amount of literature has come to light regarding the mechanisms of microglial activation and alluding to the function of microgliosis around injured motoneurons and sensory afferents. Herein, we provide a comparative analysis of the dorsal and ventral horns in relation to mechanisms of microglia activation (CSF1, DAP12, CCR2, Fractalkine signaling, Toll-like receptors, and purinergic signaling), and functionality in neuroprotection, degeneration, regeneration, synaptic plasticity, and spinal circuit reorganization following peripheral nerve injury. This review aims to shed new light on unsettled controversies regarding the diversity of spinal microglial-neuronal interactions following injury.
Collapse
Affiliation(s)
- Tana S. Pottorf
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
| | - Travis M. Rotterman
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA;
| | - William M. McCallum
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
| | - Zoë A. Haley-Johnson
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
| | - Francisco J. Alvarez
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
- Correspondence:
| |
Collapse
|
20
|
Abstract
VEGF was initially discovered due to its angiogenic activity and therefore named "vascular endothelial growth factor." However, its more recently discovered neurotrophic activity may be evolutionarily more ancient. Our previous work showed that all the changes produced by axotomy on the firing activity and synaptic inputs of abducens motoneurons were completely restored after VEGF administration. Therefore, we hypothesized that the lack of VEGF delivered by retrograde transport from the periphery should also affect the physiology of otherwise intact abducens motoneurons. For VEGF retrograde blockade, we chronically applied a neutralizing VEGF antibody to the lateral rectus muscle. Recordings of extracellular single-unit activity and eye movements were made in alert cats before and after the application of the neutralizing antibody. Our data revealed that intact, noninjured abducens motoneurons retrogradely deprived of VEGF exhibited noticeable changes in their firing pattern. There is a general decrease in firing rate and a significant reduction in eye position and eye velocity sensitivity (i.e., a decrease in the tonic and phasic components of their discharge, respectively). Moreover, by means of confocal immunocytochemistry, motoneurons under VEGF blockade showed a marked reduction in the density of afferent synaptic terminals contacting with their cell bodies. Altogether, the present findings demonstrate that the lack of retrogradely delivered VEGF renders abducens motoneurons into an axotomy-like state. This indicates that VEGF is an essential retrograde factor for motoneuronal synaptic drive and discharge activity.
Collapse
|
21
|
Chalif JI, Mentis GZ. Normal Development and Pathology of Motoneurons: Anatomy, Electrophysiological Properties, Firing Patterns and Circuit Connectivity. ADVANCES IN NEUROBIOLOGY 2022; 28:63-85. [PMID: 36066821 DOI: 10.1007/978-3-031-07167-6_3] [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: 06/15/2023]
Abstract
This chapter will provide an introduction into motoneuron anatomy, electrophysiological properties, firing patterns focusing on development and also describing several pathological conditions that affect mononeurons. It starts with a historical retrospective describing the early landmark work into motoneurons. The next section lays out the various types of motoneurons (alpha, beta, and gamma) and their subclasses (fast-twitch fatigable, fast-twitch fatigue-resistant, and slow-twitch fatigue resistant), highlighting the functional relevance of this classification scheme. The third section describes the development of motoneurons' passive and active electrophysiological properties. This section also defines the major terms one uses in describing how a neuron functions electrophysiologically. The electrophysiological aspects of a neuron is critical to understanding how it behaves within a circuit and contributes to behavior since the firing of an action potential is how neurons communicate with each other and with muscles. The electrophysiological changes of motoneurons over development underlies how their function changes over the lifetime of an organism. After describing the properties of individual motoneurons, the chapter then turns to revealing how motoneurons interact within complex neural circuits, with other motoneurons as well as sensory neurons, and how these circuits change over development. Finally, this chapter ends with highlighting some recent advances made in motoneuron pathology, focusing on spinal muscular atrophy, amyotrophic lateral sclerosis, and axotomy.
Collapse
Affiliation(s)
- Joshua I Chalif
- Departments of Neurology and Pathology & Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard University, Boston, MA, USA
| | - George Z Mentis
- Departments of Neurology and Pathology & Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA.
| |
Collapse
|
22
|
Tolkachev VS, Bazhanov SP, Matveeva OV, Korshunova GA, Shuvalov SD, Ulyanov VY, Ostrovskij VV. Degeneration Of Spinal Ganglion And Segmental Apparatus Of The Spinal Neurons In Sciatic Nerve Injury: An Experimental Study. RUSSIAN OPEN MEDICAL JOURNAL 2021. [DOI: 10.15275/rusomj.2021.0424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Objective — To investigate the extent of degenerative changes in neurons of spinal ganglion and segmental apparatus in various injuries to sciatic nerve in the experiment on white rats. Material and Methods — The research involved 40 white non-pedigree male rats distributed among four groups. The animals of Group 1 (n=10) underwent the compression of nerve trunks with Mosquito clamp forceps for 15 minutes. In Group 2 (n=10), the animals had their nerve trunks ligated; and in Group 3, they had their nerves completely transected in their middle thirds. The separate group of control animals (n=10) suffered no damage to their sciatic nerves. Spinal cords and spinal ganglia at L4-L6 level were the material for histopathological examination. We calculated the number (percent) of degenerated neurons in spinal cords and spinal ganglia at the affected sides on Day 30, and compared them to those at the intact sides. Results — The number (percent) of degenerated neurons in spinal cord and spinal ganglion, expressed as Me (Q1; Q2), constituted 2.52% (1.92; 2.74) and 3.75% (2.37; 4.74) in Group 1, 9.27% (9.03; 9.94) and 16.74% (16.01; 18.22) in Group 2, 25.59% (24.36; 26.29) and 31.94% (31.44; 33.03) in Group 3, respectively. Depending on the number (percent) of degenerated neurons, we classified three grades of change manifestation: mild (Group 1), medium (Group 2), and severe (Group 3). No degenerated neurons were found in the control animals. Conclusion — The compression, ischemic exposure on the sciatic nerve, and complete anatomical transection of its trunk resulted in Wallerian degeneration, as well as degeneration of segmental apparatus in spinal cord neurons.
Collapse
Affiliation(s)
| | | | - Olga V. Matveeva
- Saratov State Medical University n.a. V.I. Razumovsky, Saratov, Russia
| | | | | | | | | |
Collapse
|
23
|
Abstract
When animals walk overground, mechanical stimuli activate various receptors located in muscles, joints, and skin. Afferents from these mechanoreceptors project to neuronal networks controlling locomotion in the spinal cord and brain. The dynamic interactions between the control systems at different levels of the neuraxis ensure that locomotion adjusts to its environment and meets task demands. In this article, we describe and discuss the essential contribution of somatosensory feedback to locomotion. We start with a discussion of how biomechanical properties of the body affect somatosensory feedback. We follow with the different types of mechanoreceptors and somatosensory afferents and their activity during locomotion. We then describe central projections to locomotor networks and the modulation of somatosensory feedback during locomotion and its mechanisms. We then discuss experimental approaches and animal models used to investigate the control of locomotion by somatosensory feedback before providing an overview of the different functional roles of somatosensory feedback for locomotion. Lastly, we briefly describe the role of somatosensory feedback in the recovery of locomotion after neurological injury. We highlight the fact that somatosensory feedback is an essential component of a highly integrated system for locomotor control. © 2021 American Physiological Society. Compr Physiol 11:1-71, 2021.
Collapse
Affiliation(s)
- Alain Frigon
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Quebec, Canada
| | - Turgay Akay
- Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Boris I Prilutsky
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| |
Collapse
|
24
|
Mason MRJ, Erp S, Wolzak K, Behrens A, Raivich G, Verhaagen J. The Jun-dependent axon regeneration gene program: Jun promotes regeneration over plasticity. Hum Mol Genet 2021; 31:1242-1262. [PMID: 34718572 PMCID: PMC9029231 DOI: 10.1093/hmg/ddab315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/13/2021] [Accepted: 10/25/2021] [Indexed: 11/25/2022] Open
Abstract
The regeneration-associated gene (RAG) expression program is activated in injured peripheral neurons after axotomy and enables long-distance axon re-growth. Over 1000 genes are regulated, and many transcription factors are upregulated or activated as part of this response. However, a detailed picture of how RAG expression is regulated is lacking. In particular, the transcriptional targets and specific functions of the various transcription factors are unclear. Jun was the first-regeneration-associated transcription factor identified and the first shown to be functionally important. Here we fully define the role of Jun in the RAG expression program in regenerating facial motor neurons. At 1, 4 and 14 days after axotomy, Jun upregulates 11, 23 and 44% of the RAG program, respectively. Jun functions relevant to regeneration include cytoskeleton production, metabolic functions and cell activation, and the downregulation of neurotransmission machinery. In silico analysis of promoter regions of Jun targets identifies stronger over-representation of AP1-like sites than CRE-like sites, although CRE sites were also over-represented in regions flanking AP1 sites. Strikingly, in motor neurons lacking Jun, an alternative SRF-dependent gene expression program is initiated after axotomy. The promoters of these newly expressed genes exhibit over-representation of CRE sites in regions near to SRF target sites. This alternative gene expression program includes plasticity-associated transcription factors and leads to an aberrant early increase in synapse density on motor neurons. Jun thus has the important function in the early phase after axotomy of pushing the injured neuron away from a plasticity response and towards a regenerative phenotype.
Collapse
Affiliation(s)
- Matthew R J Mason
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105, BA, Amsterdam, The Netherlands
| | - Susan Erp
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105, BA, Amsterdam, The Netherlands
| | - Kim Wolzak
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105, BA, Amsterdam, The Netherlands
| | - Axel Behrens
- Adult Stem Cell Laboratory, The Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Gennadij Raivich
- UCL Institute for Women's Health, Maternal and Fetal Medicine, Perinatal Brain Repair Group, London, WC1E 6HX, United Kingdom
| | - Joost Verhaagen
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105, BA, Amsterdam, The Netherlands.,Center for Neurogenomics and Cognition Research, Neuroscience Campus Amsterdam, Vrije Universiteit Amsterdam, 1081HV, Amsterdam, The Netherlands
| |
Collapse
|
25
|
Spinal Cord Injury Significantly Alters the Properties of Reticulospinal Neurons: I. Biophysical Properties, Firing Patterns, Excitability, and Synaptic Inputs. Cells 2021; 10:cells10081921. [PMID: 34440690 PMCID: PMC8392545 DOI: 10.3390/cells10081921] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 11/17/2022] Open
Abstract
Following spinal cord injury (SCI) for larval lampreys, descending axons of reticulospinal (RS) neurons regenerate, and locomotor function gradually recovers. In the present study, the electrophysiological properties of uninjured (left)-injured (right) pairs of large, identified RS neurons were compared following rostral, right spinal cord hemi-transections (HTs). First, changes in firing patterns of injured RS neurons began in as little as 2-3 days following injury, these changes were maximal at ~2-3 weeks (wks), and by 12-16 wks normal firing patterns were restored for the majority of neurons. Second, at ~2-3 wks following spinal cord HTs, injured RS neurons displayed several significant changes in properties compared to uninjured neurons: (a) more hyperpolarized VREST; (b) longer membrane time constant and larger membrane capacitance; (c) increased voltage and current thresholds for action potentials (APs); (d) larger amplitudes and durations for APs; (e) higher slope for the repolarizing phase of APs; (f) virtual absence of some afterpotential components, including the slow afterhyperpolarization (sAHP); (g) altered, injury-type firing patterns; and (h) reduced average and peak firing (spiking) frequencies during applied depolarizing currents. These altered properties, referred to as the "injury phenotype", reduced excitability and spiking frequencies of injured RS neurons compared to uninjured neurons. Third, artificially injecting a current to add a sAHP waveform following APs for injured neurons or removing the sAHP following APs for uninjured neurons did not convert these neurons to normal firing patterns or injury-type firing patterns, respectively. Fourth, trigeminal sensory-evoked synaptic responses recorded from uninjured and injured pairs of RS neurons were not significantly different. Following SCI, injured lamprey RS neurons displayed several dramatic changes in their biophysical properties that are expected to reduce calcium influx and provide supportive intracellular conditions for axonal regeneration.
Collapse
|
26
|
English AW, Berglund K, Carrasco D, Goebel K, Gross RE, Isaacson R, Mistretta OC, Wynans C. Bioluminescent Optogenetics: A Novel Experimental Therapy to Promote Axon Regeneration after Peripheral Nerve Injury. Int J Mol Sci 2021; 22:ijms22137217. [PMID: 34281270 PMCID: PMC8269199 DOI: 10.3390/ijms22137217] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 11/18/2022] Open
Abstract
Functional recovery after peripheral nerve injury (PNI) is poor, mainly due to the slow and incomplete regeneration of injured axons. Experimental therapies that increase the excitability of the injured axons have proven remarkably successful in promoting regeneration, but their clinical applicability has been limited. Bioluminescent optogenetics (BL-OG) uses luminopsins, fusion proteins of light-generating luciferase and light-sensing ion channels that could be used to increase neuronal excitability if exposed to a suitable substrate. Excitatory luminopsins were expressed in motoneurons of transgenic mice and in wildtype mice transduced with adeno-associated viral vectors. Intraperitoneal administration of coelenterazine (CTZ), a known luciferase substrate, generated intense bioluminescence in peripheral axons. This bioluminescence increased motoneuron excitability. A single administration of CTZ immediately after sciatic nerve transection and repair markedly enhanced motor axon regeneration. Compound muscle action potentials were 3–4 times larger than controls by 4 weeks after injury. The results observed with transgenic mice were comparable to those of mice in which the luminopsin was expressed using viral vectors. Significantly more motoneurons had successfully reinnervated muscle targets four weeks after nerve injury in BL-OG treated mice than in controls. Bioluminescent optogenetics is a promising therapeutic approach to enhancing axon regeneration after PNI.
Collapse
Affiliation(s)
- Arthur W. English
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
- Correspondence:
| | - Ken Berglund
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.B.); (R.E.G.)
| | - Dario Carrasco
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Katharina Goebel
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Robert E. Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.B.); (R.E.G.)
| | - Robin Isaacson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Olivia C. Mistretta
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Carly Wynans
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| |
Collapse
|
27
|
Zilundu PLM, Xu X, Liaquat Z, Wang Y, Zhong K, Fu R, Zhou L. Long-Term Suppression of c-Jun and nNOS Preserves Ultrastructural Features of Lower Motor Neurons and Forelimb Function after Brachial Plexus Roots Avulsion. Cells 2021; 10:1614. [PMID: 34203264 PMCID: PMC8307634 DOI: 10.3390/cells10071614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 12/13/2022] Open
Abstract
Brachial plexus root avulsions cause debilitating upper limb paralysis. Short-term neuroprotective treatments have reported preservation of motor neurons and function in model animals while reports of long-term benefits of such treatments are scarce, especially the morphological sequelae. This morphological study investigated the long-term suppression of c-Jun- and neuronal nitric oxide synthase (nNOS) (neuroprotective treatments for one month) on the motor neuron survival, ultrastructural features of lower motor neurons, and forelimb function at six months after brachial plexus roots avulsion. Neuroprotective treatments reduced oxidative stress and preserved ventral horn motor neurons at the end of the 28-day treatment period relative to vehicle treated ones. Motor neuron sparing was associated with suppression of c-Jun, nNOS, and pro-apoptotic proteins Bim and caspases at this time point. Following 6 months of survival, neutral red staining revealed a significant loss of most of the motor neurons and ventral horn atrophy in the avulsed C6, 7, and 8 cervical segments among the vehicle-treated rats (n = 4). However, rats that received neuroprotective treatments c-Jun JNK inhibitor, SP600125 (n = 4) and a selective inhibitor of nNOS, 7-nitroindazole (n = 4), retained over half of their motor neurons in the ipsilateral avulsed side compared. Myelinated axons in the avulsed ventral horns of vehicle-treated rats were smaller but numerous compared to the intact contralateral ventral horns or neuroprotective-treated groups. In the neuroprotective treatment groups, there was the preservation of myelin thickness around large-caliber axons. Ultrastructural evaluation also confirmed the preservation of organelles including mitochondria and synapses in the two groups that received neuroprotective treatments compared with vehicle controls. Also, forelimb functional evaluation demonstrated that neuroprotective treatments improved functional abilities in the rats. In conclusion, neuroprotective treatments aimed at suppressing degenerative c-Jun and nNOS attenuated apoptosis, provided long-term preservation of motor neurons, their organelles, ventral horn size, and forelimb function.
Collapse
Affiliation(s)
- Prince Last Mudenda Zilundu
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
| | - Xiaoying Xu
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
| | - Zaara Liaquat
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen 518100, China;
| | - Yaqiong Wang
- Department of Electron Microscopy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China;
| | - Ke Zhong
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
| | - Rao Fu
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen 518100, China;
| | - Lihua Zhou
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen 518100, China;
| |
Collapse
|
28
|
Salvany S, Casanovas A, Piedrafita L, Tarabal O, Hernández S, Calderó J, Esquerda JE. Microglial recruitment and mechanisms involved in the disruption of afferent synaptic terminals on spinal cord motor neurons after acute peripheral nerve injury. Glia 2021; 69:1216-1240. [PMID: 33386754 PMCID: PMC7986680 DOI: 10.1002/glia.23959] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022]
Abstract
Peripheral nerve section with subsequent disconnection of motor neuron (MN) cell bodies from their skeletal muscle targets leads to a rapid reactive response involving the recruitment and activation of microglia. In addition, the loss of afferent synapses on MNs occurs in concomitance with microglial reaction by a process described as synaptic stripping. However, the way in which postaxotomy‐activated microglia adjacent to MNs are involved in synaptic removal is less defined. Here, we used confocal and electron microscopy to examine interactions between recruited microglial cells and presynaptic terminals in axotomized MNs between 1 and 15 days after sciatic nerve transection in mice. We did not observe any bulk engulfment of synaptic boutons by microglia. Instead, microglial cells internalized small membranous‐vesicular fragments which originated from the acute disruption of synaptic terminals involving the activation of the necroptotic pathway. The presence of abundant extracellular vesicles in the perineuronal space after axotomy, together with the increased expression of phospho‐mixed lineage kinase domain‐like protein and, later, of extracellular vesicle markers, such as CD9, CD63, and flotillin, indicate that the vesicles mainly originated in synapses and were transferred to microglia. The upregulation of Rab7 and Rab10 in microglia interacting with injured MNs, indicated the activation of endocytosis. As activated microglia and synaptic boutons displayed positive C1q immunoreactivity, a complement‐mediated opsonization may also contribute to microglial‐mediated synaptic disruption. In addition to the relevance of our data in the context of neuroinflammation and MN disease, they should also be taken into account for understanding functional recovery after peripheral nerve injury.
Collapse
Affiliation(s)
- Sara Salvany
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Anna Casanovas
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Olga Tarabal
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Sara Hernández
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Jordi Calderó
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| |
Collapse
|
29
|
Spinal Reflex Recovery after Dorsal Rhizotomy and Repair with Platelet-Rich Plasma (PRP) Gel Combined with Bioengineered Human Embryonic Stem Cells (hESCs). Stem Cells Int 2020; 2020:8834360. [PMID: 33178285 PMCID: PMC7647752 DOI: 10.1155/2020/8834360] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/20/2020] [Accepted: 09/30/2020] [Indexed: 02/07/2023] Open
Abstract
Dorsal root rhizotomy (DRZ) is currently considered an untreatable injury, resulting in the loss of sensitive function and usually leading to neuropathic pain. In this context, we recently proposed a new surgical approach to treat DRZ that uses platelet-rich plasma (PRP) gel to restore the spinal reflex. Success was correlated with the reentry of primary afferents into the spinal cord. Here, aiming to enhance previous results, cell therapy with bioengineered human embryonic stem cells (hESCs) to overexpress fibroblast growth factor 2 (FGF2) was combined with PRP. For these experiments, adult female rats were submitted to a unilateral rhizotomy of the lumbar spinal dorsal roots, which was followed by root repair with PRP gel with or without bioengineered hESCs. One week after DRZ, the spinal cords were processed to evaluate changes in the glial response (GFAP and Iba-1) and excitatory synaptic circuits (VGLUT1) by immunofluorescence. Eight weeks postsurgery, the lumbar intumescences were processed for analysis of the repaired microenvironment by transmission electron microscopy. Spinal reflex recovery was evaluated by the electronic Von Frey method for eight weeks. The transcript levels for human FGF2 were over 37-fold higher in the induced hESCs than in the noninduced and the wildtype counterparts. Altogether, the results indicate that the combination of hESCs with PRP gel promoted substantial and prominent axonal regeneration processes after DRZ. Thus, the repair of dorsal roots, if done appropriately, may be considered an approach to regain sensory-motor function after dorsal root axotomy.
Collapse
|
30
|
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.
Collapse
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
| |
Collapse
|
31
|
Carvalho NZM, Chiarotto GB, Bernardes D, Kempe PRG, Oliveira ALR. Neuroprotection by dimethyl fumarate following ventral root crush in C57BL/6J mice. Brain Res Bull 2020; 164:184-197. [PMID: 32866558 DOI: 10.1016/j.brainresbull.2020.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/22/2020] [Accepted: 08/13/2020] [Indexed: 01/22/2023]
Abstract
CNS lesions usually result in permanent loss of function and are an important problem in the medical field. In order to investigate neuroprotection/degeneration mechanisms and the synaptic plasticity of motoneurons, in addition to the potential for a variety of treatments, different experimental models of axonal injury have been proposed. Recent studies have tested the immunomodulatory drug dimethyl fumarate (DMF) for the treatment of neurodegenerative diseases and have shown promising outcomes. Therefore, in this work, we investigated the effects of DMF with regard to neuroprotection and its influence on the glial response in C57BL/6J animals subjected to crushing of the motor roots in the lumbar intumescence of the spinal cord. The animals were divided into a vehicle-treated injury group (0.08 % methylcellulose solution control group, n = 7) and injured groups treated with DMF at different doses (15, 30, 45, 90 and 180 mg/kg; n = 6-7 per dose). The 90 mg/kg dose showed the best neuroprotective results, so it was used for treatment over a period of eight weeks. Neuronal survival was assessed through Nissl staining, and functional recovery was evaluated with the CatWalk system (walking track test) and the von Frey test (mechanoreception). Immunohistochemistry was used to assess synaptic coverage and astroglial and microglial reactivity using the primary antibodies anti-synaptophysin (pre-synaptic terminal pan marker), GAD65 (GABAergic pre-synaptic terminations - inhibitory), and VGLUT1 (glutamatergic pre-synaptic terminations - excitatory). Glial reactions were evaluated with anti-IBA1 (microglia) and GFAP (astrocytes). Gene transcript levels of IL-3, IL-4, TNF-α, IL-6, TGF-β, iNOS-M1, and arginase-M2 were quantified by RT-qPCR. The results indicated that treatment with DMF, at a dose of 90 mg/kg, promoted neuroprotection and immunomodulation towards an anti-inflammatory response. It also resulted in greater preservation of inhibitory synapses and reduced astroglial reactivity, providing a more favorable environment for sensorimotor recovery.
Collapse
Affiliation(s)
| | - Gabriela Bortolança Chiarotto
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas - UNICAMP. 13083-970, Campinas, SP, Brazil; University Center of Herminio Ometto Foundation, Post Graduate Program in Biomedical Science, Brazil.
| | - Danielle Bernardes
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas - UNICAMP. 13083-970, Campinas, SP, Brazil; University Center of Herminio Ometto Foundation, Post Graduate Program in Biomedical Science, Brazil.
| | - Paula Regina Gelinski Kempe
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas - UNICAMP. 13083-970, Campinas, SP, Brazil.
| | - Alexandre Leite Rodrigues Oliveira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas - UNICAMP. 13083-970, Campinas, SP, Brazil.
| |
Collapse
|
32
|
Rotterman TM, Alvarez FJ. Microglia Dynamics and Interactions with Motoneurons Axotomized After Nerve Injuries Revealed By Two-Photon Imaging. Sci Rep 2020; 10:8648. [PMID: 32457369 PMCID: PMC7250868 DOI: 10.1038/s41598-020-65363-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 05/01/2020] [Indexed: 01/08/2023] Open
Abstract
The significance of activated microglia around motoneurons axotomized after nerve injuries has been intensely debated. In particular, whether microglia become phagocytic is controversial. To resolve these issues we directly observed microglia behaviors with two-photon microscopy in ex vivo spinal cord slices from CX3CR1-GFP mice complemented with confocal analyses of CD68 protein. Axotomized motoneurons were retrogradely-labeled from muscle before nerve injuries. Microglia behaviors close to axotomized motoneurons greatly differ from those within uninjured motor pools. They develop a phagocytic phenotype as early as 3 days after injury, characterized by frequent phagocytic cups, high phagosome content and CD68 upregulation. Interactions between microglia and motoneurons changed with time after axotomy. Microglia first extend processes that end in phagocytic cups at the motoneuron surface, then they closely attach to the motoneuron while extending filopodia over the cell body. Confocal 3D analyses revealed increased microglia coverage of the motoneuron cell body surface with time after injury and the presence of CD68 granules in microglia surfaces opposed to motoneurons. Some microglia formed macroclusters associated with dying motoneurons. Microglia in these clusters display the highest CD68 expression and associate with cytotoxic T-cells. These observations are discussed in relation to current theories on microglia function around axotomized motoneurons.
Collapse
Affiliation(s)
- Travis M Rotterman
- Department of Physiology, Emory University, Atlanta, GA, 30322, United States of America.,School of Biological Sciences, Georgia Tech, Atlanta, GA, 30318, United States of America
| | - Francisco J Alvarez
- Department of Physiology, Emory University, Atlanta, GA, 30322, United States of America.
| |
Collapse
|