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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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2
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Fisher KM, Garner JP, Darian-Smith C. Chronic Adaptations in the Dorsal Horn Following a Cervical Spinal Cord Injury in Primates. J Neurosci 2024; 44:e0877232023. [PMID: 38233220 PMCID: PMC10860610 DOI: 10.1523/jneurosci.0877-23.2023] [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: 05/08/2023] [Revised: 11/21/2023] [Accepted: 12/01/2023] [Indexed: 01/19/2024] Open
Abstract
Spinal cord injury (SCI) is devastating, with limited treatment options and variable outcomes. Most in vivo SCI research has focused on the acute and early post-injury periods, and the promotion of axonal growth, so little is understood about the clinically stable chronic state, axonal growth over time, and what plasticity endures. Here, we followed animals into the chronic phase following SCI, to address this gap. Male macaques received targeted deafferentation, affecting three digits of one hand, and were divided into short (4-6 months) or long-term (11-12 months) groups, based on post-injury survival times. Monkeys were assessed behaviorally, where possible, and all exhibited an initial post-injury deficit in manual dexterity, with gradual functional recovery over 2 months. We previously reported extensive sprouting of somatosensory corticospinal (S1 CST) fibers in the dorsal horn in the first five post-injury months. Here, we show that by 1 year, the S1 CST sprouting is pruned, with the terminal territory resembling control animals. This was reflected in the number of putatively "functional" synapses observed, which increased over the first 4-5 months, and then returned to baseline by 1 year. Microglia density also increased in the affected dorsal horn at 4-6 months and then decreased, but did not return to baseline by 1 year, suggesting refinement continues beyond this time. Overall, there is a long period of reorganization and consolidation of adaptive circuitry in the dorsal horn, extending well beyond the initial behavioral recovery. This provides a potential window to target therapeutic opportunities during the chronic phase.
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Affiliation(s)
- Karen M Fisher
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford 94305-5342, California
| | - Joseph P Garner
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford 94305-5342, California
| | - Corinna Darian-Smith
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford 94305-5342, California
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3
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Tan S, Faull RLM, Curtis MA. The tracts, cytoarchitecture, and neurochemistry of the spinal cord. Anat Rec (Hoboken) 2023; 306:777-819. [PMID: 36099279 DOI: 10.1002/ar.25079] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/01/2022] [Accepted: 09/11/2022] [Indexed: 11/06/2022]
Abstract
The human spinal cord can be described using a range of nomenclatures with each providing insight into its structure and function. Here we have comprehensively reviewed the key literature detailing the general structure, configuration of tracts, the cytoarchitecture of Rexed's laminae, and the neurochemistry at the spinal segmental level. The purpose of this review is to detail current anatomical understanding of how the spinal cord is structured and to aid researchers in identifying gaps in the literature that need to be studied to improve our knowledge of the spinal cord which in turn will improve the potential of therapeutic intervention for disorders of the spinal cord.
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Affiliation(s)
- Sheryl Tan
- Centre for Brain Research and Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research and Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research and Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
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Van Steenbergen V, Burattini L, Trumpp M, Fourneau J, Aljović A, Chahin M, Oh H, D’Ambra M, Bareyre FM. Coordinated neurostimulation promotes circuit rewiring and unlocks recovery after spinal cord injury. J Exp Med 2022; 220:213780. [PMID: 36571760 PMCID: PMC9794600 DOI: 10.1084/jem.20220615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 10/26/2022] [Accepted: 12/15/2022] [Indexed: 12/27/2022] Open
Abstract
Functional recovery after incomplete spinal cord injury depends on the effective rewiring of neuronal circuits. Here, we show that selective chemogenetic activation of either corticospinal projection neurons or intraspinal relay neurons alone led to anatomically restricted plasticity and little functional recovery. In contrast, coordinated stimulation of both supraspinal centers and spinal relay stations resulted in marked and circuit-specific enhancement of neuronal rewiring, shortened EMG latencies, and improved locomotor recovery.
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Affiliation(s)
- Valérie Van Steenbergen
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany
| | - Laura Burattini
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany
| | - Michelle Trumpp
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany
| | - Julie Fourneau
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany
| | - Almir Aljović
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany,Graduate School of Systemic Neurosciences, LMU Munich, Planegg-Martinsried, Germany
| | - Maryam Chahin
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany,Graduate School of Systemic Neurosciences, LMU Munich, Planegg-Martinsried, Germany
| | - Hanseul Oh
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany,Graduate School of Systemic Neurosciences, LMU Munich, Planegg-Martinsried, Germany
| | - Marta D’Ambra
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany
| | - Florence M. Bareyre
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany,Biomedical Center Munich (BMC), Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany,Munich Cluster of Systems Neurology (SyNergy), LMU Munich, Munich, Germany,Correspondence to Florence M. Bareyre:
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Selective plasticity of callosal neurons in the adult contralesional cortex following murine traumatic brain injury. Nat Commun 2022; 13:2659. [PMID: 35551446 PMCID: PMC9098892 DOI: 10.1038/s41467-022-29992-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
Traumatic brain injury (TBI) results in deficits that are often followed by recovery. The contralesional cortex can contribute to this process but how distinct contralesional neurons and circuits respond to injury remains to be determined. To unravel adaptations in the contralesional cortex, we used chronic in vivo two-photon imaging. We observed a general decrease in spine density with concomitant changes in spine dynamics over time. With retrograde co-labeling techniques, we showed that callosal neurons are uniquely affected by and responsive to TBI. To elucidate circuit connectivity, we used monosynaptic rabies tracing, clearing techniques and histology. We demonstrate that contralesional callosal neurons adapt their input circuitry by strengthening ipsilateral connections from pre-connected areas. Finally, functional in vivo two-photon imaging demonstrates that the restoration of pre-synaptic circuitry parallels the restoration of callosal activity patterns. Taken together our study thus delineates how callosal neurons structurally and functionally adapt following a contralateral murine TBI. Which contralesional circuits adapt after traumatic brain injury (TBI) is unclear. Here the authors used in vivo imaging, retrograde labeling, rabies tracing, clearing and functional imaging to demonstrate that callosal neurons selectively adapt after TBI in mice.
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Le Ray D, Guayasamin M. How Does the Central Nervous System for Posture and Locomotion Cope With Damage-Induced Neural Asymmetry? Front Syst Neurosci 2022; 16:828532. [PMID: 35308565 PMCID: PMC8927091 DOI: 10.3389/fnsys.2022.828532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/07/2022] [Indexed: 12/28/2022] Open
Abstract
In most vertebrates, posture and locomotion are achieved by a biomechanical apparatus whose effectors are symmetrically positioned around the main body axis. Logically, motor commands to these effectors are intrinsically adapted to such anatomical symmetry, and the underlying sensory-motor neural networks are correspondingly arranged during central nervous system (CNS) development. However, many developmental and/or life accidents may alter such neural organization and acutely generate asymmetries in motor operation that are often at least partially compensated for over time. First, we briefly present the basic sensory-motor organization of posturo-locomotor networks in vertebrates. Next, we review some aspects of neural plasticity that is implemented in response to unilateral central injury or asymmetrical sensory deprivation in order to substantially restore symmetry in the control of posturo-locomotor functions. Data are finally discussed in the context of CNS structure-function relationship.
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Moreno-López Y, Hollis ER. Sensory Circuit Remodeling and Movement Recovery After Spinal Cord Injury. Front Neurosci 2021; 15:787690. [PMID: 34955735 PMCID: PMC8692650 DOI: 10.3389/fnins.2021.787690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/10/2021] [Indexed: 12/18/2022] Open
Abstract
Restoring sensory circuit function after spinal cord injury (SCI) is essential for recovery of movement, yet current interventions predominantly target motor pathways. Integrated cortical sensorimotor networks, disrupted by SCI, are critical for perceiving, shaping, and executing movement. Corticocortical connections between primary sensory (S1) and motor (M1) cortices are critical loci of functional plasticity in response to learning and injury. Following SCI, in the motor cortex, corticocortical circuits undergo dynamic remodeling; however, it remains unknown how rehabilitation shapes the plasticity of S1-M1 networks or how these changes may impact recovery of movement.
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Affiliation(s)
| | - Edmund R Hollis
- Burke Neurological Institute, White Plains, NY, United States.,Weill Cornell Medicine, Feil Family Brain & Mind Research Institute, New York, NY, United States
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Guérout N. Plasticity of the Injured Spinal Cord. Cells 2021; 10:cells10081886. [PMID: 34440655 PMCID: PMC8395000 DOI: 10.3390/cells10081886] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 12/11/2022] Open
Abstract
Complete spinal cord injury (SCI) leads to permanent motor, sensitive and sensory deficits. In humans, there is currently no therapy to promote recovery and the only available treatments include surgical intervention to prevent further damage and symptomatic relief of pain and infections in the acute and chronic phases, respectively. Basically, the spinal cord is classically viewed as a nonregenerative tissue with limited plasticity. Thereby the establishment of the “glial” scar which appears within the SCI is mainly described as a hermetic barrier for axon regeneration. However, recent discoveries have shed new light on the intrinsic functional plasticity and endogenous recovery potential of the spinal cord. In this review, we will address the different aspects that the spinal cord plasticity can take on. Indeed, different experimental paradigms have demonstrated that axonal regrowth can occur even after complete SCI. Moreover, recent articles have demonstrated too that the “glial” scar is in fact composed of several cellular populations and that each of them exerts specific roles after SCI. These recent discoveries underline the underestimation of the plasticity of the spinal cord at cellular and molecular levels. Finally, we will address the modulation of this endogenous spinal cord plasticity and the perspectives of future therapeutic opportunities which can be offered by modulating the injured spinal cord microenvironment.
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Affiliation(s)
- Nicolas Guérout
- EA3830 GRHV, Institute for Research and Innovation in Biomedicine (IRIB), Normandie Université, UNIROUEN, 76000 Rouen, France
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Liao Z, Wang W, Deng W, Zhang Y, Song A, Deng S, Zhao H, Zhang S, Li Z. Human Umbilical Cord Mesenchymal Stem Cells-Secreted TSG-6 Is Anti-Inflammatory and Promote Tissue Repair After Spinal Cord Injury. ASN Neuro 2021. [PMCID: PMC8135204 DOI: 10.1177/17590914211010628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spinal cord injury (SCI) causes patients paralysis and hard to recover. The therapeutic effects of current clinical drugs are accompanied by side effects. In recent years, stem cell therapy has attracted the attention of researchers. Human umbilical cord mesenchymal stem cells (hucMSCs) have been widely used in various diseases due to their excellent paracrine function. TNF-stimulated gene 6 (TSG-6), a secretion factor of stem cells, may play an important role in hucMSCs in the treatment of SCI. So we conducted an experiment to explore its effect. We first observed that the expression of TSG-6 increased in SCI rats after injected with hucMSCs. Then, we used siRNA to knowdown the expression of TSG-6. We treated SCI rats with TSG-6-knockdown hucMSCs. Without TSG-6 expression, hucMSCs treatment made the tissue recovery worse and the number of Nissl bodies less. Meanwhile, neutrophils infiltrated more in the damaged parts. Our research also proved that TSG-6 may help demyelination recovering and alleviate astrocytes gathering in the injury sites. Our study revealed that hucMSCs secreted TSG-6 may decrease the degeneration of myelin sheath, reduce inflammation, decrease neuron loss and promote tissue repair. These results provided a new therapeutic factor for the treatment of SCI.
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Affiliation(s)
- Ziling Liao
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Wei Wang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Weiyue Deng
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Yuying Zhang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Aishi Song
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Sihao Deng
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
- NHC Key Laboratory of Birth Defect for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Huifang Zhao
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | | | - Zhiyuan Li
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
- NHC Key Laboratory of Birth Defect for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- Changsha Stomatological Hospital, Changsha, China
- GZMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China
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