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Dominguez-Bajo A, Clotman F. Potential Roles of Specific Subclasses of Premotor Interneurons in Spinal Cord Function Recovery after Traumatic Spinal Cord Injury in Adults. Cells 2024; 13:652. [PMID: 38667267 PMCID: PMC11048910 DOI: 10.3390/cells13080652] [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: 03/01/2024] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024] Open
Abstract
The differential expression of transcription factors during embryonic development has been selected as the main feature to define the specific subclasses of spinal interneurons. However, recent studies based on single-cell RNA sequencing and transcriptomic experiments suggest that this approach might not be appropriate in the adult spinal cord, where interneurons show overlapping expression profiles, especially in the ventral region. This constitutes a major challenge for the identification and direct targeting of specific populations that could be involved in locomotor recovery after a traumatic spinal cord injury in adults. Current experimental therapies, including electrical stimulation, training, pharmacological treatments, or cell implantation, that have resulted in improvements in locomotor behavior rely on the modulation of the activity and connectivity of interneurons located in the surroundings of the lesion core for the formation of detour circuits. However, very few publications clarify the specific identity of these cells. In this work, we review the studies where premotor interneurons were able to create new intraspinal circuits after different kinds of traumatic spinal cord injury, highlighting the difficulties encountered by researchers, to classify these populations.
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Affiliation(s)
- Ana Dominguez-Bajo
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology (LIBST), Animal Molecular and Cellular Biology Group (AMCB), Place Croix du Sud 4–5, 1348 Louvain la Neuve, Belgium
| | - Frédéric Clotman
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology (LIBST), Animal Molecular and Cellular Biology Group (AMCB), Place Croix du Sud 4–5, 1348 Louvain la Neuve, Belgium
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Kerzonkuf M, Verneuil J, Brocard C, Dingu N, Trouplin V, Ramirez Franco JJ, Bartoli M, Brocard F, Bras H. Knockdown of calpain1 in lumbar motoneurons reduces spasticity after spinal cord injury in adult rats. Mol Ther 2024; 32:1096-1109. [PMID: 38291756 DOI: 10.1016/j.ymthe.2024.01.029] [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: 04/20/2023] [Revised: 12/23/2023] [Accepted: 01/23/2024] [Indexed: 02/01/2024] Open
Abstract
Spasticity, affecting ∼75% of patients with spinal cord injury (SCI), leads to hyperreflexia, muscle spasms, and cocontractions of antagonist muscles, greatly affecting their quality of life. Spasticity primarily stems from the hyperexcitability of motoneurons below the lesion, driven by an upregulation of the persistent sodium current and a downregulation of chloride extrusion. This imbalance results from the post-SCI activation of calpain1, which cleaves Nav1.6 channels and KCC2 cotransporters. Our study was focused on mitigating spasticity by specifically targeting calpain1 in spinal motoneurons. We successfully transduced lumbar motoneurons in adult rats with SCI using intrathecal administration of adeno-associated virus vector serotype 6, carrying a shRNA sequence against calpain1. This approach significantly reduced calpain1 expression in transduced motoneurons, leading to a noticeable decrease in spasticity symptoms, including hyperreflexia, muscle spasms, and cocontractions in hindlimb muscles, which are particularly evident in the second month post-SCI. In addition, this decrease, which prevented the escalation of spasticity to a severe grade, paralleled the restoration of KCC2 levels in transduced motoneurons, suggesting a reduced proteolytic activity of calpain1. These findings demonstrate that inhibiting calpain1 in motoneurons is a promising strategy for alleviating spasticity in SCI patients.
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Affiliation(s)
- Marjorie Kerzonkuf
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Jérémy Verneuil
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Cécile Brocard
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Nejada Dingu
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Virginie Trouplin
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Jose Jorge Ramirez Franco
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Marc Bartoli
- Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université and INSERM, Marseille, France
| | - Frédéric Brocard
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France.
| | - Hélène Bras
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France.
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Ertlen C, Seblani M, Bonnet M, Brezun JM, Coyle T, Sabatier F, Fuentes S, Decherchi P, Serratrice N, Marqueste T. Efficacy of the immediate adipose-derived stromal vascular fraction autograft on functional sensorimotor recovery after spinal cord contusion in rats. Stem Cell Res Ther 2024; 15:29. [PMID: 38303017 PMCID: PMC10835949 DOI: 10.1186/s13287-024-03645-z] [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: 09/13/2023] [Accepted: 01/23/2024] [Indexed: 02/03/2024] Open
Abstract
BACKGROUND Spinal cord injuries (SCI) lead to functional alteration with important consequences such as motor and sensory disorders. The repair strategies developed to date remain ineffective. The adipose tissue-derived stromal vascular fraction (SVF) is composed of a cocktail of cells with trophic, pro-angiogenic and immunomodulatory effects. Numerous therapeutic benefits were shown for tissue reconstitution, peripheral neuropathy and for the improvement of neurodegenerative diseases. Here, the therapeutic efficacy of SVF on sensorimotor recovery after an acute thoracic spinal cord contusion in adult rats was determined. METHOD Male Sprague Dawley rats (n = 45) were divided into 3 groups: SHAM (without SCI and treatment), NaCl (animals with a spinal lesion and receiving a saline injection through the dura mater) and SVF (animals with a spinal lesion and receiving a fraction of fat removed from adipocytes through the dura mater). Some animals were sacrificed 14 days after the start of the experiment to determine the inflammatory reaction by measuring the interleukin-1β, interleukin-6 and Tumor Necrosis Factor-α in the lesion area. Other animals were followed once a week for 12 weeks to assess functional recovery (postural and locomotor activities, sensorimotor coordination). At the end of this period, spinal reflexivity (rate-dependent depression of the H-reflex) and physiological adjustments (ventilatory response to metabosensitive muscle activation following muscle fatigue) were measured with electrophysiological tools. RESULTS Compared to non-treated animals, results indicated that the SVF reduced the endogenous inflammation and increased the behavioral recovery in treated animals. Moreover, H-reflex depression and ventilatory adjustments to muscle fatigue were found to be comparable between SHAM and SVF groups. CONCLUSION Our results highlight the effectiveness of SVF and its high therapeutic potential to improve sensorimotor functions and to restore the segmental sensorimotor loop and the communication between supra- and sub-lesional spinal cord regions after traumatic contusion.
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Affiliation(s)
- Céline Ertlen
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France
| | - Mostafa Seblani
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France
| | - Maxime Bonnet
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France
| | - Jean-Michel Brezun
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France
| | - Thelma Coyle
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France
| | - Florence Sabatier
- Assistance Publique - Hôpitaux de Marseille (AP-HM), INSERM 1409 Centre d'Investigation Clinique en Biothérapies, Unité de Culture Et Thérapie Cellulaire, Hôpital de La Conception, 147, Boulevard Baille, 13385, Marseille Cedex 05, France
| | - Stéphane Fuentes
- Assistance Publique - Hôpitaux de Marseille (AP-HM), Service de Neurochirurgie, Hôpital de La Timone, 264, Rue Saint-Pierre, 13005, Marseille, France
| | - Patrick Decherchi
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France.
| | - Nicolas Serratrice
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France
- Assistance Publique - Hôpitaux de Marseille (AP-HM), Service de Neurochirurgie, Hôpital de La Timone, 264, Rue Saint-Pierre, 13005, Marseille, France
| | - Tanguy Marqueste
- Aix-Marseille Univ, CNRS, ISM UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY, Equipe Plasticité Des Systèmes Nerveux Et Musculaire (PSNM), Parc Scientifique Et Technologique de Luminy, Aix Marseille Univ, CC910 - 163, Avenue de Luminy, 13288, Marseille Cedex 09, France.
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Wang Y, Su H, Zhong J, Zhan Z, Zhao Q, Liu Y, Li S, Wang H, Yang C, Yu L, Tan B, Yin Y. Osteopontin enhances the effect of treadmill training and promotes functional recovery after spinal cord injury. MOLECULAR BIOMEDICINE 2023; 4:44. [PMID: 38015348 PMCID: PMC10684450 DOI: 10.1186/s43556-023-00154-y] [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: 07/08/2023] [Accepted: 11/05/2023] [Indexed: 11/29/2023] Open
Abstract
In this study, we examined the combined impact of osteopontin (OPN) and treadmill training on mice with spinal cord injury (SCI). OPN was overexpressed by injecting AAV9-SPP1-GFP into the sensorimotor cortex, followed by a left incomplete C5 crush injury two weeks later. Mice (Ex or Ex + OPN group) were trained at 50% maximum running speed for 8 weeks. To analyze the effects, we used biotinylated dextran amine (BDA) for tracing the corticospinal tract (CST) and performed Western blotting and immunohistochemical methods to assess the activation of the mammalian target of rapamycin (mTOR). We also examined axonal regeneration and conducted behavioral tests to measure functional recovery. The results demonstrated that treadmill training promoted the expression of neurotrophic factors such as brain-derived neurotrophic factor (BNDF) and insulin-like growth factor I (IGF-1) and activated mTOR signaling. OPN amplified the effect of treadmill training on activating mTOR signaling indicated by upregulated phosphorylation of ribosomal protein S6 kinase (S6). The combination of OPN and exercise further promoted functional recovery and facilitated limited CST axonal regeneration which did not occur with treadmill training and OPN treatment alone. These findings indicate that OPN enhances the effects of treadmill training in the treatment of SCI and offer new therapeutic insights for spinal cord injury.
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Affiliation(s)
- Yunhang Wang
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
- Department of Rehabilitation, Zhejiang University School of Medicine Second Affiliated Hospital, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
| | - Hong Su
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Juan Zhong
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Zuxiong Zhan
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Qin Zhao
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Yuan Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, Department of Special War Wound, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Sen Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Department of Special War Wound, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Haiyan Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Department of Special War Wound, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Ce Yang
- State Key Laboratory of Trauma, Burns and Combined Injury, Department of Special War Wound, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Lehua Yu
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Botao Tan
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
| | - Ying Yin
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
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Goltash S, Stevens SJ, Topcu E, Bui TV. Changes in synaptic inputs to dI3 INs and MNs after complete transection in adult mice. Front Neural Circuits 2023; 17:1176310. [PMID: 37476398 PMCID: PMC10354275 DOI: 10.3389/fncir.2023.1176310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/21/2023] [Indexed: 07/22/2023] Open
Abstract
Introduction Spinal cord injury (SCI) is a debilitating condition that disrupts the communication between the brain and the spinal cord. Several studies have sought to determine how to revive dormant spinal circuits caudal to the lesion to restore movements in paralyzed patients. So far, recovery levels in human patients have been modest at best. In contrast, animal models of SCI exhibit more recovery of lost function. Previous work from our lab has identified dI3 interneurons as a spinal neuron population central to the recovery of locomotor function in spinalized mice. We seek to determine the changes in the circuitry of dI3 interneurons and motoneurons following SCI in adult mice. Methods After a complete transection of the spinal cord at T9-T11 level in transgenic Isl1:YFP mice and subsequent treadmill training at various time points of recovery following surgery, we examined changes in three key circuits involving dI3 interneurons and motoneurons: (1) Sensory inputs from proprioceptive and cutaneous afferents, (2) Presynaptic inhibition of sensory inputs, and (3) Central excitatory glutamatergic synapses from spinal neurons onto dI3 INs and motoneurons. Furthermore, we examined the possible role of treadmill training on changes in synaptic connectivity to dI3 interneurons and motoneurons. Results Our data suggests that VGLUT1+ inputs to dI3 interneurons decrease transiently or only at later stages after injury, whereas levels of VGLUT1+ remain the same for motoneurons after injury. Levels of VGLUT2+ inputs to dI3 INs and MNs may show transient increases but fall below levels seen in sham-operated mice after a period of time. Levels of presynaptic inhibition to VGLUT1+ inputs to dI3 INs and MNs can rise shortly after SCI, but those increases do not persist. However, levels of presynaptic inhibition to VGLUT1+ inputs never fell below levels observed in sham-operated mice. For some synaptic inputs studied, levels were higher in spinal cord-injured animals that received treadmill training, but these increases were observed only at some time points. Discussion These results suggest remodeling of spinal circuits involving spinal interneurons that have previously been implicated in the recovery of locomotor function after spinal cord injury in mice.
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Metz K, Matos IC, Li Y, Afsharipour B, Thompson CK, Negro F, Quinlan KA, Bennett DJ, Gorassini MA. Facilitation of sensory transmission to motoneurons during cortical or sensory-evoked primary afferent depolarization (PAD) in humans. J Physiol 2023; 601:1897-1924. [PMID: 36916205 PMCID: PMC11037101 DOI: 10.1113/jp284275] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Sensory and corticospinal tract (CST) pathways activate spinal GABAergic interneurons that have axoaxonic connections onto proprioceptive (Ia) afferents that cause long-lasting depolarizations (termed primary afferent depolarization, PAD). In rodents, sensory-evoked PAD is produced by GABAA receptors at nodes of Ranvier in Ia afferents, rather than at presynaptic terminals, and facilitates spike propagation to motoneurons by preventing branch-point failures, rather than causing presynaptic inhibition. We examined in 40 human participants whether putative activation of Ia-PAD by sensory or CST pathways can also facilitate Ia afferent activation of motoneurons via the H-reflex. H-reflexes in several leg muscles were facilitated by prior conditioning from low-threshold proprioceptive, cutaneous or CST pathways, with a similar long-lasting time course (∼200 ms) to phasic PAD measured in rodent Ia afferents. Long trains of cutaneous or proprioceptive afferent conditioning produced longer-lasting facilitation of the H-reflex for up to 2 min, consistent with tonic PAD in rodent Ia afferents mediated by nodal α5-GABAA receptors for similar stimulation trains. Facilitation of H-reflexes by this conditioning was likely not mediated by direct facilitation of the motoneurons because isolated stimulation of sensory or CST pathways did not alone facilitate the tonic firing rate of motor units. Furthermore, cutaneous conditioning increased the firing probability of single motor units (motoneurons) during the H-reflex without increasing their firing rate at this time, indicating that the underlying excitatory postsynaptic potential was more probable, but not larger. These results are consistent with sensory and CST pathways activating nodal GABAA receptors that reduce intermittent failure of action potentials propagating into Ia afferent branches. KEY POINTS: Controlled execution of posture and movement requires continually adjusted feedback from peripheral sensory pathways, especially those that carry proprioceptive information about body position, movement and effort. It was previously thought that the flow of proprioceptive feedback from Ia afferents was only reduced by GABAergic neurons in the spinal cord that sent axoaxonic projections to the terminal endings of sensory axons (termed GABAaxo neurons). Based on new findings in rodents, we provide complementary evidence in humans to suggest that sensory and corticospinal pathways known to activate GABAaxo neurons that project to dorsal parts of the Ia afferent also increase the flow of proprioceptive feedback to motoneurons in the spinal cord. These findings support a new role for spinal GABAaxo neurons in facilitating afferent feedback to the spinal cord during voluntary or reflexive movements.
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Affiliation(s)
- Krista Metz
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Isabel Concha Matos
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Yaqing Li
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Babak Afsharipour
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | | | - Francesco Negro
- Clinical and Experimental Sciences, Universita degli Studi di Brescia, Brescia, Italy
| | - Katharina A Quinlan
- George and Anne Ryan Institute for Neuroscience, Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, USA
| | - David J Bennett
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Monica A Gorassini
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
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Talifu Z, Pan Y, Gong H, Xu X, Zhang C, Yang D, Gao F, Yu Y, Du L, Li J. The role of KCC2 and NKCC1 in spinal cord injury: From physiology to pathology. Front Physiol 2022; 13:1045520. [PMID: 36589461 PMCID: PMC9799334 DOI: 10.3389/fphys.2022.1045520] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
The balance of ion concentrations inside and outside the cell is an essential homeostatic mechanism in neurons and serves as the basis for a variety of physiological activities. In the central nervous system, NKCC1 and KCC2, members of the SLC12 cation-chloride co-transporter (CCC) family, participate in physiological and pathophysiological processes by regulating intracellular and extracellular chloride ion concentrations, which can further regulate the GABAergic system. Over recent years, studies have shown that NKCC1 and KCC2 are essential for the maintenance of Cl- homeostasis in neural cells. NKCC1 transports Cl- into cells while KCC2 transports Cl- out of cells, thereby regulating chloride balance and neuronal excitability. An imbalance of NKCC1 and KCC2 after spinal cord injury will disrupt CI- homeostasis, resulting in the transformation of GABA neurons from an inhibitory state into an excitatory state, which subsequently alters the spinal cord neural network and leads to conditions such as spasticity and neuropathic pain, among others. Meanwhile, studies have shown that KCC2 is also an essential target for motor function reconstruction after spinal cord injury. This review mainly introduces the physiological structure and function of NKCC1 and KCC2 and discusses their pathophysiological roles after spinal cord injury.
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Affiliation(s)
- Zuliyaer Talifu
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China
| | - Yunzhu Pan
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China
| | - Han Gong
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Xin Xu
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Chunjia Zhang
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Degang Yang
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Feng Gao
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Yan Yu
- School of Rehabilitation, Capital Medical University, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Liangjie Du
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,*Correspondence: Liangjie Du, ; Jianjun Li,
| | - Jianjun Li
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China,*Correspondence: Liangjie Du, ; Jianjun Li,
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Lukacova N, Kisucka A, Kiss Bimbova K, Bacova M, Ileninova M, Kuruc T, Galik J. Glial-Neuronal Interactions in Pathogenesis and Treatment of Spinal Cord Injury. Int J Mol Sci 2021; 22:13577. [PMID: 34948371 PMCID: PMC8708227 DOI: 10.3390/ijms222413577] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/14/2022] Open
Abstract
Traumatic spinal cord injury (SCI) elicits an acute inflammatory response which comprises numerous cell populations. It is driven by the immediate response of macrophages and microglia, which triggers activation of genes responsible for the dysregulated microenvironment within the lesion site and in the spinal cord parenchyma immediately adjacent to the lesion. Recently published data indicate that microglia induces astrocyte activation and determines the fate of astrocytes. Conversely, astrocytes have the potency to trigger microglial activation and control their cellular functions. Here we review current information about the release of diverse signaling molecules (pro-inflammatory vs. anti-inflammatory) in individual cell phenotypes (microglia, astrocytes, blood inflammatory cells) in acute and subacute SCI stages, and how they contribute to delayed neuronal death in the surrounding spinal cord tissue which is spared and functional but reactive. In addition, temporal correlation in progressive degeneration of neurons and astrocytes and their functional interactions after SCI are discussed. Finally, the review highlights the time-dependent transformation of reactive microglia and astrocytes into their neuroprotective phenotypes (M2a, M2c and A2) which are crucial for spontaneous post-SCI locomotor recovery. We also provide suggestions on how to modulate the inflammation and discuss key therapeutic approaches leading to better functional outcome after SCI.
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Affiliation(s)
- Nadezda Lukacova
- Institute of Neurobiology, Biomedical Research Centre, Slovak Academy of Sciences, Soltesovej 4–6, 040 01 Kosice, Slovakia; (A.K.); (K.K.B.); (M.B.); (M.I.); (T.K.); (J.G.)
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França de Barros F, Bacqué-Cazenave J, Taillebuis C, Courtand G, Manuel M, Bras H, Tagliabue M, Combes D, Lambert FM, Beraneck M. Conservation of locomotion-induced oculomotor activity through evolution in mammals. Curr Biol 2021; 32:453-461.e4. [PMID: 34856124 DOI: 10.1016/j.cub.2021.11.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/04/2021] [Accepted: 11/09/2021] [Indexed: 10/19/2022]
Abstract
Efference copies are neural replicas of motor outputs used to anticipate the sensory consequences of a self-generated motor action or to coordinate neural networks involved in distinct motor behaviors.1 An established example of this motor-to-motor coupling is the efference copy of the propulsive motor command, which supplements classical visuo-vestibular reflexes to ensure gaze stabilization during amphibian larval locomotion.2 Such feedforward replica of spinal pattern-generating circuits produces a spino-extraocular motor coupled activity that evokes eye movements, spatiotemporally coordinated to tail undulation independently of any sensory signal.3,4 Exploiting the developmental stages of the frog,1 studies in metamorphing Xenopus demonstrated the persistence of this spino-extraocular motor command in adults and its developmental adaptation to tetrapodal locomotion.5,6 Here, we demonstrate for the first time the existence of a comparable locomotor-to-ocular motor coupling in the mouse. In neonates, ex vivo nerve recordings of brainstem-spinal cord preparations reveal a spino-extraocular motor coupled activity similar to the one described in Xenopus. In adult mice, trans-synaptic rabies virus injections in lateral rectus eye muscle label cervical spinal cord neurons closely connected to abducens motor neurons. Finally, treadmill-elicited locomotion in decerebrated preparations7 evokes rhythmic eye movements in synchrony with the limb gait pattern. Overall, our data are evidence for the conservation of locomotor-induced eye movements in vertebrate lineages. Thus, in mammals as in amphibians, CPG-efference copy feedforward signals might interact with sensory feedback to ensure efficient gaze control during locomotion.
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Affiliation(s)
- Filipa França de Barros
- Université de Paris, CNRS, Integrative Neuroscience and Cognition Center, F-75006 Paris, France
| | - Julien Bacqué-Cazenave
- Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, INCIA CNRS UMR 5287, 33076 Université de Bordeaux, Bordeaux, France
| | - Coralie Taillebuis
- Université de Paris, CNRS, Integrative Neuroscience and Cognition Center, F-75006 Paris, France; Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, INCIA CNRS UMR 5287, 33076 Université de Bordeaux, Bordeaux, France
| | - Gilles Courtand
- Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, INCIA CNRS UMR 5287, 33076 Université de Bordeaux, Bordeaux, France
| | - Marin Manuel
- Université de Paris, CNRS, Saints-Pères Institute for the Neurosciences, F-75006 Paris, France; Department of Biomedical and Pharmaceutical Sciences and George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
| | - Hélène Bras
- Institut de Neurosciences de la Timone, UMR 7289 CNRS-AMU, 13385 Marseille, France
| | - Michele Tagliabue
- Université de Paris, CNRS, Integrative Neuroscience and Cognition Center, F-75006 Paris, France
| | - Denis Combes
- Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, INCIA CNRS UMR 5287, 33076 Université de Bordeaux, Bordeaux, France
| | - François M Lambert
- Institut des Neurosciences Cognitives et Intégratives d'Aquitaine, INCIA CNRS UMR 5287, 33076 Université de Bordeaux, Bordeaux, France.
| | - Mathieu Beraneck
- Université de Paris, CNRS, Integrative Neuroscience and Cognition Center, F-75006 Paris, France.
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Treadmill training based on the overload principle promotes locomotor recovery in a mouse model of chronic spinal cord injury. Exp Neurol 2021; 345:113834. [PMID: 34370998 DOI: 10.1016/j.expneurol.2021.113834] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/16/2021] [Accepted: 08/02/2021] [Indexed: 11/21/2022]
Abstract
Rehabilitative treatment, including treadmill training, is considered an important strategy for restoring motor function after spinal cord injury (SCI). However, many unexplained problems persist regarding the appropriate rehabilitative method and the mechanism underlying the beneficial effects of rehabilitation. Moreover, only a few preclinical studies have been performed on rehabilitative interventions for chronic SCI, although most patients have chronic injuries. In fact, several preclinical studies reported that rehabilitative training was less effective when applied during the chronic phase than when applied sooner. While numerous studies have examined the effects of treadmill training during the subacute phase, the training conditions vary considerably among preclinical reports. Therefore, establishing a standard training protocol is essential for achieving beneficial rehabilitation effects at the chronic stage. Since the difficulty of applying an appropriate training load hinders training at constant speeds, it is important to adjust the training intensity in accordance with the exercise tolerance of an individual animal to provide further functional recovery benefits. Here, we created a novel quadrupedal treadmill training protocol based on the overload principle for mice with incomplete thoracic SCI. We subjected SCI model mice to rehabilitative training according to the protocol for two consecutive weeks starting at 42 days after injury. We examined the treadmill speeds at which the mice were able to run based on the severity of paresis and investigated the impact of the protocol on functional recovery. Assessment of running speed changes during the treadmill training period revealed faster treadmill speeds for mice with mild paresis than for those with severe paresis. The training parameters, including the speed and distance traveled, were positively correlated with the changes in motor function. These results suggest that the most suitable running speed during treadmill training differs according to the level of motor dysfunction and that running longer distances has a positive impact on motor functional recovery. Based on this established protocol, we compared functional and histological results between the chronic SCI groups with and without rehabilitation. The gait analyses showed significantly better functional improvement in the rehabilitation group than in the nonrehabilitation group. Histological analyses revealed that the BDNF- and VGLUT1-positive areas of lumbar enlargement were significantly increased in the rehabilitation group. These findings implied that rehabilitation promoted not only motor performance but also motor control, including forelimb-hindlimb coordination, even in chronic SCI, resulting in functional improvement by treadmill training alone. Therefore, rehabilitative training based on the overload principle appears to be one of the appropriate treatment options for incomplete thoracic SCI, and evidence of its efficacy exists in actual clinical settings.
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Bilchak JN, Caron G, Côté MP. Exercise-Induced Plasticity in Signaling Pathways Involved in Motor Recovery after Spinal Cord Injury. Int J Mol Sci 2021; 22:ijms22094858. [PMID: 34064332 PMCID: PMC8124911 DOI: 10.3390/ijms22094858] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 02/06/2023] Open
Abstract
Spinal cord injury (SCI) leads to numerous chronic and debilitating functional deficits that greatly affect quality of life. While many pharmacological interventions have been explored, the current unsurpassed therapy for most SCI sequalae is exercise. Exercise has an expansive influence on peripheral health and function, and by activating the relevant neural pathways, exercise also ameliorates numerous disorders of the central nervous system (CNS). While the exact mechanisms by which this occurs are still being delineated, major strides have been made in the past decade to understand the molecular underpinnings of this essential treatment. Exercise rapidly and prominently affects dendritic sprouting, synaptic connections, neurotransmitter production and regulation, and ionic homeostasis, with recent literature implicating an exercise-induced increase in neurotrophins as the cornerstone that binds many of these effects together. The field encompasses vast complexity, and as the data accumulate, disentangling these molecular pathways and how they interact will facilitate the optimization of intervention strategies and improve quality of life for individuals affected by SCI. This review describes the known molecular effects of exercise and how they alter the CNS to pacify the injury environment, increase neuronal survival and regeneration, restore normal neural excitability, create new functional circuits, and ultimately improve motor function following SCI.
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GABAergic Mechanisms Can Redress the Tilted Balance between Excitation and Inhibition in Damaged Spinal Networks. Mol Neurobiol 2021; 58:3769-3786. [PMID: 33826070 PMCID: PMC8279998 DOI: 10.1007/s12035-021-02370-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 03/22/2021] [Indexed: 12/19/2022]
Abstract
Correct operation of neuronal networks depends on the interplay between synaptic excitation and inhibition processes leading to a dynamic state termed balanced network. In the spinal cord, balanced network activity is fundamental for the expression of locomotor patterns necessary for rhythmic activation of limb extensor and flexor muscles. After spinal cord lesion, paralysis ensues often followed by spasticity. These conditions imply that, below the damaged site, the state of balanced networks has been disrupted and that restoration might be attempted by modulating the excitability of sublesional spinal neurons. Because of the widespread expression of inhibitory GABAergic neurons in the spinal cord, their role in the early and late phases of spinal cord injury deserves full attention. Thus, an early surge in extracellular GABA might be involved in the onset of spinal shock while a relative deficit of GABAergic mechanisms may be a contributor to spasticity. We discuss the role of GABA A receptors at synaptic and extrasynaptic level to modulate network excitability and to offer a pharmacological target for symptom control. In particular, it is proposed that activation of GABA A receptors with synthetic GABA agonists may downregulate motoneuron hyperexcitability (due to enhanced persistent ionic currents) and, therefore, diminish spasticity. This approach might constitute a complementary strategy to regulate network excitability after injury so that reconstruction of damaged spinal networks with new materials or cell transplants might proceed more successfully.
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Gong C, Zheng X, Guo F, Wang Y, Zhang S, Chen J, Sun X, Shah SZA, Zheng Y, Li X, Yin Y, Li Q, Huang X, Guo T, Han X, Zhang SC, Wang W, Chen H. Human spinal GABA neurons alleviate spasticity and improve locomotion in rats with spinal cord injury. Cell Rep 2021; 34:108889. [PMID: 33761348 DOI: 10.1016/j.celrep.2021.108889] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/21/2020] [Accepted: 03/01/2021] [Indexed: 01/10/2023] Open
Abstract
Spinal cord injury (SCI) often results in spasticity. There is currently no effective therapy for spasticity. Here, we describe a method to efficiently differentiate human pluripotent stem cells from spinal GABA neurons. After transplantation into the injured rat spinal cord, the DREADD (designer receptors exclusively activated by designer drug)-expressing spinal progenitors differentiate into GABA neurons, mitigating spasticity-like response of the rat hindlimbs and locomotion deficits in 3 months. Administering clozapine-N-oxide, which activates the grafted GABA neurons, further alleviates spasticity-like response, suggesting an integration of grafted GABA neurons into the local neural circuit. These results highlight the therapeutic potential of the spinal GABA neurons for SCI.
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Affiliation(s)
- ChenZi Gong
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaolong Zheng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - FangLiang Guo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - YaNan Wang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Song Zhang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jing Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - XueJiao Sun
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Sayed Zulfiqar Ali Shah
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - YiFeng Zheng
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiao Li
- School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Yatao Yin
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qian Li
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - XiaoLin Huang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tiecheng Guo
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaohua Han
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Su-Chun Zhang
- Waisman Center, Department of Neuroscience and Department of Neurology, University of Wisconsin, Madison, WI, USA; Program in Neuroscience & Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Pan L, Tan B, Tang W, Luo M, Liu Y, Yu L, Yin Y. Combining task-based rehabilitative training with PTEN inhibition promotes axon regeneration and upper extremity skilled motor function recovery after cervical spinal cord injury in adult mice. Behav Brain Res 2021; 405:113197. [PMID: 33621609 DOI: 10.1016/j.bbr.2021.113197] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/30/2021] [Accepted: 02/17/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Conditional deletion of Pten in corticospinal neurons promotes axon sprouting and regeneration after spinal cord injury (SCI). However, regeneration studies targeted on PTEN inhibition seldom show motor function recovery. The promotion of functional recovery can be improved by rehabilitative training under a use-dependent plasticity mechanism. PURPOSE To investigate the combined effects of PTEN inhibition and rehabilitative training on axon regeneration and subsequent motor functional improvement after cervical spinal cord injury. METHODS Lentiviral particles (Lenti-PTEN-RNAi or Lenti-Scrambled-EGFP) were injected into the right sensorimotor mouse cortex in four experimental groups (PTEN RNAi + Training, PTEN RNAi, Control + Training, Control). Two weeks after injection, all mouse groups received a left C5 crush injury. We performed task-based rehabilitative training for 4 weeks on the PTEN RNAi + Training and Control + Training groups. Biotinylated dextran amine (BDA) was used for anterograde tracing of the dorsal corticospinal tract (dCST). We analysed axonal regeneration through immunohistochemical methods. A battery of behavioral tests was employed to assess functional recovery at Day3 and every other week after injury. RESULTS Combining rehabilitative training with PTEN inhibition induced more axon regeneration and synapse reformation in the spinal cord caudal to the lesion site. Rostral to the lesion, the transected dCST axons sprouted into gray matter upon contact. Furthermore, forelimb function was found to be improved after combination therapy during behavioral testing. CONCLUSION Combining task-based rehabilitative training with PTEN inhibition further promotes axon regeneration, synaptic plasticity and reorganization of the neural network, with significant improvement in forelimb skilled motor function after cervical spinal cord injury. Our study provides new therapeutic insights for spinal cord injury management in the future.
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Affiliation(s)
- Lu Pan
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Botao Tan
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Weiwei Tang
- Central Laboratory, Xinqiao Hospital, The Army Medical University (Third Military Medical University), Chongqing, 400037, China
| | - Meiling Luo
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Yuan Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, Department of Research Institute of Surgery, Daping Hospital, The Army Medical University, Chongqing, 400042, China
| | - Lehua Yu
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Ying Yin
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
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Lalonde NR, Bui TV. Do spinal circuits still require gating of sensory information by presynaptic inhibition after spinal cord injury? CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2020.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Caron G, Bilchak JN, Côté MP. Direct evidence for decreased presynaptic inhibition evoked by PBSt group I muscle afferents after chronic SCI and recovery with step-training in rats. J Physiol 2020; 598:4621-4642. [PMID: 32721039 DOI: 10.1113/jp280070] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/27/2020] [Indexed: 01/11/2023] Open
Abstract
KEY POINTS Presynaptic inhibition is modulated by supraspinal centres and primary afferents in order to filter sensory information, adjust spinal reflex excitability, and ensure smooth movement. After spinal cord injury (SCI), the supraspinal control of primary afferent depolarization (PAD) interneurons is disengaged, suggesting an increased role for sensory afferents. While increased H-reflex excitability in spastic individuals indicates a possible decrease in presynaptic inhibition, it remains unclear whether a decrease in sensory-evoked PAD contributes to this effect. We investigated whether the PAD evoked by hindlimb afferents contributes to the change in presynaptic inhibition of the H-reflex in a decerebrated rat preparation. We found that chronic SCI decreases presynaptic inhibition of the plantar H-reflex through a reduction in PAD evoked by posterior biceps-semitendinosus (PBSt) muscle group I afferents. We further found that step-training restored presynaptic inhibition of the plantar H-reflex evoked by PBSt, suggesting the presence of activity-dependent plasticity of PAD pathways activated by flexor muscle group I afferents. ABSTRACT Spinal cord injury (SCI) results in the disruption of supraspinal control of spinal networks and an increase in the relative influence of afferent feedback to sublesional neural networks, both of which contribute to enhancing spinal reflex excitability. Hyperreflexia occurs in ∼75% of individuals with a chronic SCI and critically hinders functional recovery and quality of life. It is suggested that it results from an increase in motoneuronal excitability and a decrease in presynaptic and postsynaptic inhibitory mechanisms. In contrast, locomotor training decreases hyperreflexia by restoring presynaptic inhibition. Primary afferent depolarization (PAD) is a powerful presynaptic inhibitory mechanism that selectively gates primary afferent transmission to spinal neurons to adjust reflex excitability and ensure smooth movement. However, the effect of chronic SCI and step-training on the reorganization of presynaptic inhibition evoked by hindlimb afferents, and the contribution of PAD has never been demonstrated. The objective of this study is to directly measure changes in presynaptic inhibition through dorsal root potentials (DRPs) and its association with plantar H-reflex inhibition. We provide direct evidence that H-reflex hyperexcitability is associated with a decrease in transmission of PAD pathways activated by posterior biceps-semitendinosus (PBSt) afferents after chronic SCI. More precisely, we illustrate that the pattern of inhibition evoked by PBSt group I muscle afferents onto both L4-DRPs and plantar H-reflexes evoked by the distal tibial nerve is impaired after chronic SCI. These changes are not observed in step-trained animals, suggesting a role for activity-dependent plasticity to regulate PAD pathways activated by flexor muscle group I afferents.
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Affiliation(s)
- Guillaume Caron
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19129
| | - Jadwiga N Bilchak
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19129
| | - Marie-Pascale Côté
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19129
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Bras H, Liabeuf S. Differential effects of spinal cord transection on glycinergic and GABAergic synaptic signaling in sub-lesional lumbar motoneurons. J Chem Neuroanat 2020; 113:101847. [PMID: 32653413 DOI: 10.1016/j.jchemneu.2020.101847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 01/11/2023]
Abstract
This review takes stock on the impact of complete spinal cord transection (SCT) on the plasticity of inhibitory synaptic transmission on sub-lesional lumbar motoneurons (MNs), differentiating between studies in neonate and adult rats. After neonatal SCT, normal maturational up-regulation of glycine receptors was observed. On the other hand, the developmental downregulation of the GABAA receptors, as well as the up-regulation of the co-transporter KCC2 were prevented, but not the normal decrease of NKCC1. In adult SCT rats, glycinergic synaptic transmission, which is the major contributor to spinal MNs inhibition in adulthood, had normal control levels 2 months post-injury. On the other hand, the GABAergic transmission was altered through an up-regulation of the pre-signaling levels and a down-regulation in the density of post synaptic receptors. KCC2 membrane expression was down-regulated at all post-injury times tested (24h to 4 months), thereby depolarizing the Cl- equilibrium potential and reducing the strength of postsynaptic inhibition. The preservation of glycinergic pre- and post signaling is probably a key factor in the success of locomotor rehabilitation programs in adult SCT rats. However, these data highlight the need to develop strategies to restore KCC2 levels in lumbar MNs, to stabilize the excitation/inhibition balance, which is essential to the effective control of skeletal muscle activity.
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Affiliation(s)
- Hélène Bras
- Institut de Neurosciences de la Timone, UMR 7289, CNRS and Aix Marseille Université, Campus Santé Timone, 13385, Marseille, France.
| | - Sylvie Liabeuf
- Institut de Neurosciences de la Timone, UMR 7289, CNRS and Aix Marseille Université, Campus Santé Timone, 13385, Marseille, France
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Alteration of glycinergic receptor expression in lumbar spinal motoneurons is involved in the mechanisms underlying spasticity after spinal cord injury. J Chem Neuroanat 2020; 106:101787. [PMID: 32339654 DOI: 10.1016/j.jchemneu.2020.101787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023]
Abstract
Spasticity is a disabling motor disorder affecting 70% of people with brain and spinal cord injury. The rate-dependent depression (RDD) of the H reflex is the only electrophysiological measurement correlated with the degree of spasticity assessed clinically in spastic patients. Several lines of evidence suggest that the mechanism underlying the H reflex RDD depends on the strength of synaptic inhibition through GABAA (GABAAR) and glycine receptors (GlyR). In adult rats with spinal cord transection (SCT), we studied the time course of the expression of GABAAR and GlyR at the membrane of retrogradely identified Gastrocnemius and Tibialis anterior motoneurons (MNs) 3, 8 and 16 weeks after injury, and measured the RDD of the H reflex at similar post lesion times. Three weeks after SCT, a significant decrease in the expression of GABAA and GlyR was observed compared to intact rats, and the H-reflex RDD was much less pronounced than in controls. Eight weeks after SCT, GlyR values returned to normal. Simultaneously, we observed a tendency to recover normal RDD of the H reflex at higher frequencies. We tested whether an anti-inflammatory treatment using methylprednisolone performed immediately after SCT could prevent alterations in GABAA/glycine receptors and/or the development of spasticity observed 3 weeks after injury. This treatment restored control levels of GlyR but not the expression of GABAAR, and it completely prevented the attenuation of RDD. These data strongly suggest that alteration of glycinergic inhibition of lumbar MNs is involved in the mechanisms underlying spasticity after SCI.
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Kobayakawa K, DePetro KA, Zhong H, Pham B, Hara M, Harada A, Nogami J, Ohkawa Y, Edgerton VR. Locomotor Training Increases Synaptic Structure With High NGL-2 Expression After Spinal Cord Hemisection. Neurorehabil Neural Repair 2019; 33:225-231. [PMID: 30782076 DOI: 10.1177/1545968319829456] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND We previously demonstrated that step training leads to reorganization of neuronal networks in the lumbar spinal cord of rodents after a hemisection (HX) injury and step training, including increases excitability of spinally evoked potentials in hindlimb motor neurons. METHODS In this study, we investigated changes in RNA expression and synapse number using RNA-Seq and immunohistochemistry of the lumbar spinal cord 23 days after a mid-thoracic HX in rats with and without post-HX step training. RESULTS Gene Ontology (GO) term clustering demonstrated that expression levels of 36 synapse-related genes were increased in trained compared with nontrained rats. Many synaptic genes were upregulated in trained rats, but Lrrc4 (coding NGL-2) was the most highly expressed in the lumbar spinal cord caudal to the HX lesion. Trained rats also had a higher number of NGL-2/synaptophysin synaptic puncta in the lumbar ventral horn. CONCLUSIONS Our findings demonstrate clear activity-dependent regulation of synapse-related gene expression post-HX. This effect is consistent with the concept that activity-dependent phenomena can provide a mechanistic drive for epigenetic neuronal group selection in the shaping of the reorganization of synaptic networks to learn the locomotion task being trained after spinal cord injury.
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Affiliation(s)
| | | | - Hui Zhong
- 1 University of California, Los Angeles, CA, USA
| | - Bau Pham
- 1 University of California, Los Angeles, CA, USA
| | | | | | | | | | - V Reggie Edgerton
- 1 University of California, Los Angeles, CA, USA.,3 Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Barcelona, Spain.,4 University of Technology Sydney, Ultimo, New South Wales, Australia
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