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Mohammadshirazi A, Mazzone GL, Zylberberg BA, Taccola G. A Focal Traumatic Injury to the Neonatal Rodent Spinal Cord Causes an Immediate and Massive Spreading Depolarization Sustained by Chloride Ions, with Transient Network Dysfunction. Cell Mol Neurobiol 2025; 45:10. [PMID: 39745523 PMCID: PMC11695467 DOI: 10.1007/s10571-024-01516-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Accepted: 11/13/2024] [Indexed: 01/06/2025]
Abstract
In clinics, physical injuries to the spinal cord cause a temporary motor areflexia below lesion, known as spinal shock. This topic is still underexplored due to the lack of preclinical spinal cord injury (SCI) models that do not use anesthesia, which would affect spinal excitability. Our innovative design considered a custom-made micro impactor that provides localized and calibrated strikes to the ventral surface of the thoracic spinal cord of the entire CNS isolated from neonatal rats. Before and after injury, multiple ventral root (VR) recordings continuously traced respiratory rhythm, baseline spontaneous activities, and electrically induced reflex responses. As early as 200 ms after the lowering of the impactor, an immediate transient depolarization spread from the injury site to the whole spinal cord with distinct segmental velocities. Stronger strikes induced higher potentials causing, close by the site of injury, a transient drop in spinal cord oxygenation (SCO2) and a massive cell death with a complete functional disconnection of input along the cord. Below the impact site, expiratory rhythm and spontaneous lumbar activity were suppressed. On lumbar VRs, reflex responses transiently halted but later recovered to control values, while electrically induced fictive locomotion remained perturbed. Moreover, low-ion modified Krebs solutions differently influenced impact-induced depolarizations, the magnitude of which amplified in low Cl-. Overall, our novel ex vivo platform traces the immediate functional consequences of impacts to the spinal cord during development. This basic study provides insights on the SCI pathophysiology, unveiling an immediate chloride dysregulation.
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Affiliation(s)
- Atiyeh Mohammadshirazi
- Neuroscience Department, International School for Advanced Studies (SISSA), Via Bonomea 265, Trieste, TS, Italy
- Applied Neurophysiology and Neuropharmacology Lab, Istituto di Medicina Fisica e Riabilitazione (IMFR), Via Gervasutta 48, Udine, UD, Italy
| | - Graciela L Mazzone
- Instituto de Investigaciones en Medicina Traslacional (IIMT), CONICET-Universidad Austral, Av. Pte. Perón 1500, B1629AHJ, Pilar, Buenos Aires, Argentina
- Facultad de Ciencias Biomédicas, Universidad Austral, Av. Pte. Perón 1500, B1629AHJ, Pilar, Buenos Aires, Argentina
| | - Benjamín A Zylberberg
- Instituto de Investigaciones en Medicina Traslacional (IIMT), CONICET-Universidad Austral, Av. Pte. Perón 1500, B1629AHJ, Pilar, Buenos Aires, Argentina
- Facultad de Ciencias Biomédicas, Universidad Austral, Av. Pte. Perón 1500, B1629AHJ, Pilar, Buenos Aires, Argentina
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies (SISSA), Via Bonomea 265, Trieste, TS, Italy.
- Applied Neurophysiology and Neuropharmacology Lab, Istituto di Medicina Fisica e Riabilitazione (IMFR), Via Gervasutta 48, Udine, UD, Italy.
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Kadam SD, Hegarty SV. Development of KCC2 therapeutics to treat neurological disorders. Front Mol Neurosci 2024; 17:1503070. [PMID: 39720463 PMCID: PMC11666659 DOI: 10.3389/fnmol.2024.1503070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2024] [Accepted: 11/27/2024] [Indexed: 12/26/2024] Open
Abstract
KCC2 is CNS neuron-specific chloride extruder, essential for the establishment and maintenance of the transmembrane chloride gradient, thereby enabling synaptic inhibition within the CNS. Herein, we highlight KCC2 hypofunction as a fundamental and conserved pathology contributing to neuronal circuit excitation/inhibition (E/I) imbalances that underly epilepsies, chronic pain, neuro-developmental/-traumatic/-degenerative/-psychiatric disorders. Indeed, downstream of both acquired and genetic factors, multiple pathologies (e.g., hyperexcitability and inflammation) converge to impair KCC2-dependent inhibition in CNS. When KCC2 hypofunction occurs, affected neurons are disinhibited due to impaired inhibitory responses to GABA/glycine. This causes neuronal hyperexcitability, disinhibition within neuron circuits, and disrupted neurological functions. More recently, KCC2 was identified as a genetically-validated target for epilepsy, intellectual disability, and autism spectrum disorder, and pathogenic mutations in human SLC12A5 gene were linked to psychiatric/mood disorders. The broad therapeutic utility of KCC2-upmodulating drugs relates to its critical role in determining inhibitory activity of GABAergic neurotransmission, a mechanism widely targeted by several drugs. However, in cases of KCC2 hypofunction GABAergic neurotransmission can be depolarizing/excitatory, thereby impairing endogenous neuronal inhibition while also limiting the effectiveness of existing therapeutics targeting/requiring GABAergic pathway inhibition. Several preclinical reports have shown that KCC2 upmodulating treatments rescue and increase the efficacy of anti-seizure and analgesic medications. Thus, a first-in-class KCC2-potentiating therapy would provide a novel mechanism for restoring physiological CNS inhibition and addressing drug resistance in patients with E/I imbalance pathologies. Herein, we discuss progress toward and further work needed to develop the first-in-class KCC2 therapeutics to treat neurological disorder patients.
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Shenkman BS, Kalashnikov VE, Sharlo KA, Turtikova OV, Bokov RO, Mirzoev TM. Continuous Use During Disuse: Mechanisms and Effects of Spontaneous Activity of Unloaded Postural Muscle. Int J Mol Sci 2024; 25:12462. [PMID: 39596527 PMCID: PMC11594575 DOI: 10.3390/ijms252212462] [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: 09/30/2024] [Revised: 11/15/2024] [Accepted: 11/18/2024] [Indexed: 11/28/2024] Open
Abstract
In most mammals, postural soleus muscles are involved in the maintenance of the stability of the body in the gravitational field of Earth. It is well established that immediately after a laboratory rat is exposed to conditions of weightlessness (parabolic flight) or simulated microgravity (hindlimb suspension/unloading), a sharp decrease in soleus muscle electrical activity occurs. However, starting from the 3rd day of mechanical unloading, soleus muscle electrical activity begins to increase and reaches baseline levels approximately by the 14th day of hindlimb suspension. This phenomenon, observed in the course of rat hindlimb suspension, was named the "spontaneous electrical activity of postural muscle". The present review discusses spinal mechanisms underlying the development of such spontaneous activity of rat soleus muscle and the effect of this activity on intracellular signaling in rat soleus muscle during mechanical unloading.
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Affiliation(s)
- Boris S. Shenkman
- Myology Lab, Institute of Biomedical Problems of the Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (K.A.S.); (O.V.T.); (R.O.B.)
| | | | | | | | | | - Timur M. Mirzoev
- Myology Lab, Institute of Biomedical Problems of the Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (K.A.S.); (O.V.T.); (R.O.B.)
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4
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Sergeeva XV, Sharlo KA, Tyganov SA, Kalashnikov VE, Shenkman BS. Molecular Signaling Effects behind the Spontaneous Soleus Muscle Activity Induced by 7-Day Rat Hindlimb Suspension. Int J Mol Sci 2024; 25:8316. [PMID: 39125886 PMCID: PMC11312583 DOI: 10.3390/ijms25158316] [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: 06/27/2024] [Revised: 07/22/2024] [Accepted: 07/28/2024] [Indexed: 08/12/2024] Open
Abstract
The elimination of ground reaction force (support withdrawal) vastly affects slow postural muscles in terms of their regulation and structure. One of the effects of support withdrawal in this study was an immediate postural muscle inactivation, followed by the daily gradual development of spontaneous activity of the slow postural soleus muscle in response to rat hindlimb suspension to mimic space flight. The origin of this activity is somewhat akin to muscle spasticity after spinal cord injuries and is the result of KCC2 content decline in the spinal cord's motor neurons. However, the physiological consequences of unloading-induced spontaneous activity remain unexplored. We have conducted an experiment with the administration of a highly specific KCC2 activator during 7-day unloading. For this experiment, 32 male Wistar rats were divided into 4 groups: C+placebo, C+CLP-290 (100 mg/kg b w), 7HS+placebo, and 7HS+CLP-hindlimb-suspended group with CLP-290 administration (100 mg/kg b w). The soleus muscles of the animals were dissected and analyzed for several proteostasis- and metabolism-related parameters. CLP-290 administration to the unloaded animals led to the upregulation of AMPK downstream (p-ACC) and mTOR targets (p-p70S6k and p-4E-BP) and an enhanced PGC1alpha decrease vs. the 7HS group, but neither prevented nor enhanced atrophy of the soleus muscle or myofiber CSA.
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Affiliation(s)
| | - Kristina A. Sharlo
- Myology Laboratory, Institute of Biomedical Problems, RAS (Russian Academy of Sciences), Moscow 123007, Russia; (X.V.S.); (S.A.T.); (V.E.K.)
| | | | | | - Boris S. Shenkman
- Myology Laboratory, Institute of Biomedical Problems, RAS (Russian Academy of Sciences), Moscow 123007, Russia; (X.V.S.); (S.A.T.); (V.E.K.)
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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 PMCID: PMC11163198 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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Keramidis I, McAllister BB, Bourbonnais J, Wang F, Isabel D, Rezaei E, Sansonetti R, Degagne P, Hamel JP, Nazari M, Inayat S, Dudley JC, Barbeau A, Froux L, Paquet ME, Godin AG, Mohajerani MH, De Koninck Y. Restoring neuronal chloride extrusion reverses cognitive decline linked to Alzheimer's disease mutations. Brain 2023; 146:4903-4915. [PMID: 37551444 PMCID: PMC10690023 DOI: 10.1093/brain/awad250] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/23/2023] [Accepted: 07/09/2023] [Indexed: 08/09/2023] Open
Abstract
Disinhibition during early stages of Alzheimer's disease is postulated to cause network dysfunction and hyperexcitability leading to cognitive deficits. However, the underlying molecular mechanism remains unknown. Here we show that, in mouse lines carrying Alzheimer's disease-related mutations, a loss of neuronal membrane potassium-chloride cotransporter KCC2, responsible for maintaining the robustness of GABAA-mediated inhibition, occurs pre-symptomatically in the hippocampus and prefrontal cortex. KCC2 downregulation was inversely correlated with the age-dependent increase in amyloid-β 42 (Aβ42). Acute administration of Aβ42 caused a downregulation of membrane KCC2. Loss of KCC2 resulted in impaired chloride homeostasis. Preventing the decrease in KCC2 using long term treatment with CLP290 protected against deterioration of learning and cortical hyperactivity. In addition, restoring KCC2, using short term CLP290 treatment, following the transporter reduction effectively reversed spatial memory deficits and social dysfunction, linking chloride dysregulation with Alzheimer's disease-related cognitive decline. These results reveal KCC2 hypofunction as a viable target for treatment of Alzheimer's disease-related cognitive decline; they confirm target engagement, where the therapeutic intervention takes place, and its effectiveness.
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Affiliation(s)
- Iason Keramidis
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
- Graduate Program in Neuroscience, Faculty of Medicine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Brendan B McAllister
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Julien Bourbonnais
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
| | - Feng Wang
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
- Faculty of Dentistry, Université Laval, Québec, QC G1V 0A6, Canada
| | - Dominique Isabel
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
| | - Edris Rezaei
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Romain Sansonetti
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
| | - Phil Degagne
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Justin P Hamel
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
| | - Mojtaba Nazari
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Samsoon Inayat
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Jordan C Dudley
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Annie Barbeau
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
| | - Lionel Froux
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
| | - Marie-Eve Paquet
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
- Department of Biochemistry, Microbiology, and Bio-informatics, Université Laval, Québec, QC G1V 0A6, Canada
| | - Antoine G Godin
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
- Graduate Program in Neuroscience, Faculty of Medicine, Université Laval, Québec, QC G1V 0A6, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC G1V 0A6, Canada
| | - Majid H Mohajerani
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC G1E 1T2, Canada
- Graduate Program in Neuroscience, Faculty of Medicine, Université Laval, Québec, QC G1V 0A6, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC G1V 0A6, Canada
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Sharlo KA, Lvova ID, Tyganov SA, Sergeeva KV, Kalashnikov VY, Kalashnikova EP, Mirzoev TM, Kalamkarov GR, Shevchenko TF, Shenkman BS. A Prochlorperazine-Induced Decrease in Autonomous Muscle Activity during Hindlimb Unloading Is Accompanied by Preserved Slow Myosin mRNA Expression. Curr Issues Mol Biol 2023; 45:5613-5630. [PMID: 37504270 PMCID: PMC10378404 DOI: 10.3390/cimb45070354] [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: 05/11/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/29/2023] Open
Abstract
Skeletal muscle disuse leads to pathological muscle activity as well as to slow-to-fast fiber-type transformation. Fast-type fibers are more fatigable than slow-type, so this transformation leads to a decline in muscle function. Prochlorperazine injections previously were shown to attenuate autonomous rat soleus muscle electrical activity under unloading conditions. In this study, we found that prochlorperazine blocks slow-to-fast fiber-type transformation in disused skeletal muscles of rats, possibly through affecting calcium and ROS-related signaling.
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Affiliation(s)
- Kristina A Sharlo
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Irina D Lvova
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Sergey A Tyganov
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Ksenia V Sergeeva
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Vitaly Y Kalashnikov
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Ekaterina P Kalashnikova
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Timur M Mirzoev
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Grigoriy R Kalamkarov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Tatiana F Shevchenko
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Boris S Shenkman
- Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
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Caron G, Bilchak J, Marie-Pascale Côté. Bumetanide increases postsynaptic inhibition after chronic SCI and decreases presynaptic inhibition with step-training. J Physiol 2023; 601:1425-1447. [PMID: 36847245 PMCID: PMC10106440 DOI: 10.1113/jp283753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 02/16/2023] [Indexed: 03/01/2023] Open
Abstract
Current anti-spastic medication significantly compromises motor recovery after spinal cord injury (SCI), indicating a critical need for alternative interventions. Because a shift in chloride homeostasis decreases spinal inhibition and contributes to hyperreflexia after SCI, we investigated the effect of bumetanide, an FDA-approved sodium-potassium-chloride intruder (NKCC1) antagonist, on presynaptic and postsynaptic inhibition. We compared its effect with step-training as it is known to improve spinal inhibition by restoring chloride homeostasis. In SCI rats, a prolonged bumetanide treatment increased postynaptic inhibition but not presynaptic inhibition of the plantar H-reflex evoked by posterior biceps and semitendinosus (PBSt) group I afferents. By using in vivo intracellular recordings of motoneurons, we further show that a prolonged bumetanide increased postsynaptic inhibition by hyperpolarizing the reversal potential for inhibitory postsynaptic potentials (IPSPs) after SCI. However, in step-trained SCI rats an acute delivery of bumetanide decreased presynaptic inhibition of the H-reflex, but not postsynaptic inhibition. These results suggest that bumetanide might be a viable option to improve postsynaptic inhibition after SCI, but it also decreases the recovery of presynaptic inhibition with step-training. We discuss whether the effects of bumetanide are mediated by NKCC1 or by off-target effects. KEY POINTS: After spinal cord injury (SCI), chloride homeostasis is dysregulated over time in parallel with the decrease in presynaptic inhibition of Ia afferents and postsynaptic inhibition of motoneurons, and the development of spasticity. While step-training counteracts these effects, it cannot always be implemented in the clinic because of comorbidities. An alternative intervention is to use pharmacological strategies to decrease spasticity without hindering the recovery of motor function with step-training. Here we found that, after SCI, a prolonged bumetanide (an FDA-approved antagonist of the sodium-potassium-chloride intruder, NKCC1) treatment increases postsynaptic inhibition of the H-reflex, and it hyperpolarizes the reversal potential for inhibitory postsynaptic potentials in motoneurons. However, in step-trained SCI, an acute delivery of bumetanide decreases presynaptic inhibition of the H-reflex, but not postsynaptic inhibition. Our results suggest that bumetanide has the potential to decrease spastic symptoms related to a decrease in postsynaptic but not presynaptic inhibition after SCI.
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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 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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9
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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: 1.7] [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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Ji B, Wojtaś B, Skup M. Molecular Identification of Pro-Excitogenic Receptor and Channel Phenotypes of the Deafferented Lumbar Motoneurons in the Early Phase after SCT in Rats. Int J Mol Sci 2022; 23:ijms231911133. [PMID: 36232433 PMCID: PMC9569670 DOI: 10.3390/ijms231911133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 02/07/2023] Open
Abstract
Spasticity impacts the quality of life of patients suffering spinal cord injury and impedes the recovery of locomotion. At the cellular level, spasticity is considered to be primarily caused by the hyperexcitability of spinal α-motoneurons (MNs) within the spinal stretch reflex circuit. Here, we hypothesized that after a complete spinal cord transection in rats, fast adaptive molecular responses of lumbar MNs develop in return for the loss of inputs. We assumed that early loss of glutamatergic afferents changes the expression of glutamatergic AMPA and NMDA receptor subunits, which may be the forerunners of the developing spasticity of hindlimb muscles. To better understand its molecular underpinnings, concomitant expression of GABA and Glycinergic receptors and serotoninergic and noradrenergic receptors, which regulate the persistent inward currents crucial for sustained discharges in MNs, were examined together with voltage-gated ion channels and cation-chloride cotransporters. Using quantitative real-time PCR, we showed in the tracer-identified MNs innervating extensor and flexor muscles of the ankle joint multiple increases in transcripts coding for AMPAR and 5-HTR subunits, along with a profound decrease in GABAAR, GlyR subunits, and KCC2. Our study demonstrated that both MNs groups similarly adapt to a more excitable state, which may increase the occurrence of extensor and flexor muscle spasms.
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Affiliation(s)
- Benjun Ji
- Group of Restorative Neurobiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Bartosz Wojtaś
- Laboratory of Sequencing, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Małgorzata Skup
- Group of Restorative Neurobiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
- Correspondence:
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11
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Molecular Mechanisms of Epilepsy: The Role of the Chloride Transporter KCC2. J Mol Neurosci 2022; 72:1500-1515. [PMID: 35819636 DOI: 10.1007/s12031-022-02041-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 06/07/2022] [Indexed: 10/17/2022]
Abstract
Epilepsy is a neurological disease characterized by abnormal or synchronous brain activity causing seizures, which may produce convulsions, minor physical signs, or a combination of symptoms. These disorders affect approximately 65 million people worldwide, from all ages and genders. Seizures apart, epileptic patients present a high risk to develop neuropsychological comorbidities such as cognitive deficits, emotional disturbance, and psychiatric disorders, which severely impair quality of life. Currently, the treatment for epilepsy includes the administration of drugs or surgery, but about 30% of the patients treated with antiepileptic drugs develop time-dependent pharmacoresistence. Therefore, further investigation about epilepsy and its causes is needed to find new pharmacological targets and innovative therapeutic strategies. Pharmacoresistance is associated to changes in neuronal plasticity and alterations of GABAA receptor-mediated neurotransmission. The downregulation of GABA inhibitory activity may arise from a positive shift in GABAA receptor reversal potential, due to an alteration in chloride homeostasis. In this paper, we review the contribution of K+-Cl--cotransporter (KCC2) to the alterations in the Cl- gradient observed in epileptic condition, and how these alterations are coupled to the increase in the excitability.
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12
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Liedtke W. Long March Toward Safe and Effective Analgesia by Enhancing Gene Expression of Kcc2: First Steps Taken. Front Mol Neurosci 2022; 15:865600. [PMID: 35645734 PMCID: PMC9137411 DOI: 10.3389/fnmol.2022.865600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/08/2022] [Indexed: 11/15/2022] Open
Abstract
Low intraneuronal chloride in spinal cord dorsal horn pain relay neurons is critical for physiologic transmission of primary pain afferents because low intraneuronal chloride dictates whether GABA-ergic and glycin-ergic neurotransmission is inhibitory. If the neuronal chloride elevates to pathologic levels, then spinal cord primary pain relay becomes leaky and exhibits the behavioral hallmarks of pathologic pain, namely hypersensitivity and allodynia. Low chloride in spinal cord dorsal horn neurons is maintained by proper gene expression of Kcc2 and sustained physiologic function of the KCC2 chloride extruding electroneutral transporter. Peripheral nerve injury and other forms of neural injury evoke greatly diminished Kcc2 gene expression and subsequent corruption of inhibitory neurotransmission in the spinal cord dorsal horn, thus causing derailment of the gate function for pain. Here I review key discoveries that have helped us understand these fundamentals, and focus on recent insights relating to the discovery of Kcc2 gene expression enhancing compounds via compound screens in neurons. One such study characterized the kinase inhibitor, kenpaullone, more in-depth, revealing its function as a robust and long-lasting analgesic in preclinical models of nerve injury and cancer bone pain, also elucidating its mechanism of action via GSK3β inhibition, diminishing delta-catenin phosphorylation, and facilitating its nuclear transfer and subsequent enhancement of Kcc2 gene expression by de-repressing Kaiso epigenetic transcriptional regulator. Future directions re Kcc2 gene expression enhancement are discussed, namely combination with other analgesics and analgesic methods, such as spinal cord stimulation and electroacupuncture, gene therapy, and leveraging Kcc2 gene expression-enhancing nanomaterials.
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Wang S, Wang P, Yin R, Xiao M, Zhang Y, Reinhardt JD, Wang H, Xu G. Combination of repetitive transcranial magnetic stimulation and treadmill training reduces hyperreflexia by rebalancing motoneuron excitability in rats after spinal cord contusion. Neurosci Lett 2022; 775:136536. [PMID: 35183693 DOI: 10.1016/j.neulet.2022.136536] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/12/2022] [Accepted: 02/15/2022] [Indexed: 11/19/2022]
Abstract
Spasticity commonly emerges during the process of recovery after spinal cord injury (SCI) and critically exacerbates motor dysfunction. Given insufficient effects of individual therapies, we combined repetitive transcranial magnetic stimulation (rTMS) with treadmill training (Tr) in rats with SCI to investigate potential synergistic effects on alleviating spasticity and motor dysfunction. Animals were randomized into four groups: SCI only, rTMS, Tr, and rTMS plus Tr. At the study endpoint eight weeks after the start of interventions, the rTMS plus Tr group exhibited the largest decrease in maximal H-reflex amplitude/maximal M-wave amplitude ratio (effect size (ES): -0.082, 95% confidence interval (CI): -0.118 to -0.046, p < 0.001) as well as the greatest improvement in motor function measured with the Basso, Beattie, and Bresnahan locomotor scale (ES: 1.811, 95% CI: 1.018 to 2.603, p < 0.001; significantly different from all other groups at p < 0.01) and grid-walking test (ES: -5.1, 95% CI: -7.784 to -2.416, p < 0.001, significantly different from rTMS alone at p < 0.01). Pathological analyses demonstrated that the combined treatment facilitated the growth of serotonergic axons around the lesion site, and the upregulation of 5-hydroxytryptamine, potassium-chloride cotransporter-2, and glutamic acid decarboxylases 67 in the lumbar spinal cord distal to the injury site. All effects of combined treatment of rTMS and treadmill training were enhanced compared to treadmill training or rTMS alone. Treadmill training and rTMS intervention appear to have synergistic effects on hyperreflexia and locomotion likely related to a restored balance between facilitatory and inhibitory inputs to motoneurons.
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Affiliation(s)
- Shuangyan Wang
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China; Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Pei Wang
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China
| | - Ruian Yin
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China
| | - Ming Xiao
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing 211166, China
| | - Yongjie Zhang
- Department of Human Anatomy, Nanjing Medical University, Nanjing 211166, China
| | - Jan D Reinhardt
- Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, China
| | - Hongxing Wang
- Department of Rehabilitation Medicine, Zhongda Hospital, Southeast University Nanjing 210024, China.
| | - Guangxu Xu
- Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
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14
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Kalashnikov VE, Tyganov SA, Turtikova OV, Kalashnikova EP, Glazova MV, Mirzoev TM, Shenkman BS. Prochlorperazine Withdraws the Delayed Onset Tonic Activity of Unloaded Rat Soleus Muscle: A Pilot Study. Life (Basel) 2021; 11:life11111161. [PMID: 34833037 PMCID: PMC8618166 DOI: 10.3390/life11111161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/16/2022] Open
Abstract
A gradual increase in rat soleus muscle electromyographic (EMG) activity is known to occur after 3–4 days of hindlimb suspension/unloading (HS). The physiological significance and mechanisms of such activity of motoneurons under unloading conditions are currently unclear. Since hyperactivity of motoneurons and muscle spasticity after spinal cord injury are associated with KCC2 downregulation, we hypothesized that a decrease in potassium (K+)/chloride (Cl−) co-transporter 2 (KCC2) in motoneurons would be responsible for an increase in soleus muscle EMG activity during HS. We aimed to investigate the effect of prochlorperazine (KCC2 activator) on the electrical activity of rat soleus muscle under HS. Wistar rats were divided into the following groups: (1) vivarium control (C), (2) 7-day HS group (7HS) and (3) 7-day HS group plus intraperitoneal injections of prochlorperazine (10 mg/kg, daily) (7HS + P). Expression of proteins in the motoneurons of the lumbar spinal cord was determined by Western blotting. An electromyogram of the rat soleus muscle was recorded using intramuscular electrodes. KCC2 content after 7-day HS significantly decreased by 34% relative to the control group. HS-induced decrease in KCC2 protein content was prevented by prochlorperazine administration. HS also induced a significant 80% decrease in KCC2 Ser940 phosphorylation; however prochlorperazine did not affect KCC2 phosphorylation. The treatment of the rats with prochlorperazine prevented a HS-induced increase in Na(+)/K(+)/(Cl−) co-transporter 1 (KCC2 antagonist) protein content. In parallel with the restoration of KCC2 content, prochlorperazine administration during HS partially prevented an increase in the soleus muscle tonic EMG activity. Thus, prochlorperazine administration during 7-day HS prevents a decrease in KCC2 protein expression in motoneurons and significantly reduces the level of HS-induced soleus muscle electrical activity.
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Affiliation(s)
- Vitaliy E. Kalashnikov
- Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (S.A.T.); (O.V.T.); (E.P.K.); (B.S.S.)
| | - Sergey A. Tyganov
- Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (S.A.T.); (O.V.T.); (E.P.K.); (B.S.S.)
| | - Olga V. Turtikova
- Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (S.A.T.); (O.V.T.); (E.P.K.); (B.S.S.)
| | - Ekaterina P. Kalashnikova
- Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (S.A.T.); (O.V.T.); (E.P.K.); (B.S.S.)
| | - Margarita V. Glazova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223 St. Petersburg, Russia;
| | - Timur M. Mirzoev
- Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (S.A.T.); (O.V.T.); (E.P.K.); (B.S.S.)
- Correspondence:
| | - Boris S. Shenkman
- Institute of Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia; (V.E.K.); (S.A.T.); (O.V.T.); (E.P.K.); (B.S.S.)
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15
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Xie L, Xie Y, Mao G, Cao S, Fang R, Zhou S, Jiang J, Yao T, Fan J, Liu D, Wu D, Ge J. Decreased spasticity of Baishaoluoshi Decoction through the BDNF/TrKB-KCC2 pathway on poststroke spasticity rats. Neuroreport 2021; 32:1183-1191. [PMID: 34284448 PMCID: PMC8389354 DOI: 10.1097/wnr.0000000000001709] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/11/2021] [Indexed: 01/02/2023]
Abstract
OBJECTIVE K+-Cl- cotransporter-2 (KCC2), which primarily extrudes chloride in mature neurons, triggers hemiplegia limb spasticity after ischemic stroke by affecting neuronal excitability. Our previous study revealed that the Chinese herb Baishaoluoshi Decoction decreases hemiplegia limb spasticity in poststroke spasticity (PSS) patients. This study aimed at elucidating on the effects of Baishaoluoshi Decoction on the BDNF/TrKB-KCC2 pathway in PSS rat models. METHODS Middle cerebral artery occlusion (MCAO) was adopted for the establishment of PSS rat models. Muscle tension was evaluated by Modified Ashworth Scale. Nissl staining and transmission electron microscopy were used to measure the protective effects of Baishaoluoshi Decoction on ischemic injury-induced neuronal damage due to MCAO. Expression levels of BDNF, TrKB, and KCC2 in brain tissues around the infarct and brainstem were detected by immunohistochemical staining. RESULTS It was found that Baishaoluoshi Decoction suppressed hemiplegia limb spasticity and alleviated the damage in neurons and synapses in PSS rat models. Importantly, the expression of BDNF, TrKB, and KCC2 in brain tissues around the infarct and brainstem were significantly upregulated after treatment with low-dose and high-dose Baishaoluoshi Decoction. CONCLUSION Suppression of spasticity by Baishaoluoshi Decoction in PSS rat models may be correlated with upregulated BDNF/TrKB-KCC2 pathway, which may be a complementary therapeutic strategy for PSS.
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Affiliation(s)
- Le Xie
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Yao Xie
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Guo Mao
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Sijia Cao
- Foreign Languages Department, School of Humanities and Management, Hunan University of Chinese Medicine
| | - Rui Fang
- Chinese Pharmacy Teaching and Research Department, College of Integrated Traditional Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan
| | - Shen Zhou
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Junlin Jiang
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Ting Yao
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Jianhu Fan
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Dong Liu
- Hunan Key Laboratory of Prevention and Treatment in Cardiovascular Disease, College of Pharmacy, Guiyang University of Chinese Medicine, Guiyang, Guizhou, China
| | - Dahua Wu
- Neurology Department, Hunan Academy of Chinese Medicine Affiliated Hospital
| | - Jinwen Ge
- Chinese Pharmacy Teaching and Research Department, College of Integrated Traditional Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan
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16
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Guo F, Zheng X, He Z, Zhang R, Zhang S, Wang M, Chen H, Wang W. Nimodipine Promotes Functional Recovery After Spinal Cord Injury in Rats. Front Pharmacol 2021; 12:733420. [PMID: 34594224 PMCID: PMC8477750 DOI: 10.3389/fphar.2021.733420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that results in severe motor, sensory, and autonomic dysfunction. The L-/T-type calcium channel blocker nimodipine (NMD) exerts a protective effect on neuronal injury; however, the protective effects of long-term administration of NMD in subjects with SCI remain unknown. Thus, the aim of this study was to evaluate the role of long-term treatment with NMD on a clinically relevant SCI model. Female rats with SCI induced by 25 mm contusion were subcutaneously injected with vehicle or 10 mg/kg NMD daily for six consecutive weeks. We monitored the motor score, hind limb grip strength, pain-related behaviors, and bladder function in this study to assess the efficacy of NMD in rats with SCI. Rats treated with NMD showed improvements in locomotion, pain-related behaviors, and spasticity-like symptoms, but not in open-field spontaneous activity, hind limb grip strength or bladder function. SCI lesion areas and perilesional neuronal numbers, gliosis and calcitonin gene-related peptide (CGRP+) fiber sprouting in the lumbar spinal cord and the expression of K+–Cl− cotransporter 2 (KCC2) on lumbar motor neurons were also observed to further explore the possible protective mechanisms of NMD. NMD-treated rats showed greater tissue preservation with reduced lesion areas and increased perilesional neuronal sparing. NMD-treated rats also showed improvements in gliosis, CGRP+ fiber sprouting in the lumbar spinal cord, and KCC2 expression in lumbar motor neurons. Together, these results indicate that long-term treatment with NMD improves functional recovery after SCI, which may provide a potential therapeutic strategy for the treatment of SCI.
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Affiliation(s)
- Fangliang Guo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaolong Zheng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ziyu He
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ruoying Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Song Zhang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minghuan Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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17
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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: 32] [Impact Index Per Article: 8.0] [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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18
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Bilchak JN, Yeakle K, Caron G, Malloy D, Côté MP. Enhancing KCC2 activity decreases hyperreflexia and spasticity after chronic spinal cord injury. Exp Neurol 2021; 338:113605. [PMID: 33453210 PMCID: PMC7904648 DOI: 10.1016/j.expneurol.2021.113605] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/21/2020] [Accepted: 01/09/2021] [Indexed: 02/03/2023]
Abstract
After spinal cord injury (SCI), the majority of individuals develop spasticity, a debilitating condition involving involuntary movements, co-contraction of antagonistic muscles, and hyperreflexia. By acting on GABAergic and Ca2+-dependent signaling, current anti-spastic medications lead to serious side effects, including a drastic decrease in motoneuronal excitability which impairs motor function and rehabilitation efforts. Exercise, in contrast, decreases spastic symptoms without decreasing motoneuron excitability. These functional improvements coincide with an increase in expression of the chloride co-transporter KCC2 in lumbar motoneurons. Thus, we hypothesized that spastic symptoms can be alleviated directly through restoration of chloride homeostasis and endogenous inhibition by increasing KCC2 activity. Here, we used the recently developed KCC2 enhancer, CLP257, to evaluate the effects of acutely increasing KCC2 extrusion capability on spastic symptoms after chronic SCI. Sprague Dawley rats received a spinal cord transection at T12 and were either bike-trained or remained sedentary for 5 weeks. Increasing KCC2 activity in the lumbar enlargement improved the rate-dependent depression of the H-reflex and reduced both phasic and tonic EMG responses to muscle stretch in sedentary animals after chronic SCI. Furthermore, the improvements due to this pharmacological treatment mirror those of exercise. Together, our results suggest that pharmacologically increasing KCC2 activity is a promising approach to decrease spastic symptoms in individuals with SCI. By acting to directly restore endogenous inhibition, this strategy has potential to avoid severe side effects and improve the quality of life of affected individuals.
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Affiliation(s)
- Jadwiga N Bilchak
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Kyle Yeakle
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Guillaume Caron
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Dillon Malloy
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Marie-Pascale Côté
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America.
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19
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Jeffrey-Gauthier R, Bouyer J, Piché M, Côté MP, Leblond H. Locomotor deficits induced by lumbar muscle inflammation involve spinal microglia and are independent of KCC2 expression in a mouse model of complete spinal transection. Exp Neurol 2021; 338:113592. [PMID: 33388315 PMCID: PMC7904639 DOI: 10.1016/j.expneurol.2020.113592] [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: 01/17/2020] [Revised: 12/03/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
Spinal cord injury (SCI) is associated with damage to musculoskeletal tissues of the spine. Recent findings show that pain and inflammatory processes caused by musculoskeletal injury mediate plastic changes in the spinal cord. These changes could impede the adaptive plastic changes responsible for functional recovery. The underlying mechanism remains unclear, but may involve the microglia-BDNF-KCC2 pathway, which is implicated in sensitization of dorsal horn neurons in neuropathic pain and in the regulation of spinal excitability by step-training. In the present study, we examined the effects of step-training and lumbar muscle inflammation induced by complete Freund's adjuvant (CFA) on treadmill locomotion in a mouse model of complete spinal transection. The impact on locomotor recovery of each of these interventions alone or in combination were examined in addition to changes in microglia and KCC2 expression in the dorsal and ventral horns of the sublesional spinal cord. Results show that angular motion at the hip, knee and ankle joint during locomotion were decreased by CFA injection and improved by step-training. Moreover, CFA injection enhanced the expression of the microglial marker Iba1 in both ventral and dorsal horns, with or without step-training. However, this change was not associated with a modulation of KCC2 expression, suggesting that locomotor deficits induced by inflammation are independent of KCC2 expression in the sublesional spinal cord. These results indicate that musculoskeletal injury hinders locomotor recovery after SCI and that microglia is involved in this effect.
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Affiliation(s)
- Renaud Jeffrey-Gauthier
- Department of Anatomy, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7, Canada; CogNAC Research Group, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7, Canada.
| | - Julien Bouyer
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, United States.
| | - Mathieu Piché
- Department of Anatomy, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7, Canada; CogNAC Research Group, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7, Canada.
| | - Marie-Pascale Côté
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, United States.
| | - Hugues Leblond
- Department of Anatomy, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7, Canada; CogNAC Research Group, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7, Canada.
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20
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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: 4] [Impact Index Per Article: 0.8] [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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21
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Duy PQ, He M, He Z, Kahle KT. Preclinical insights into therapeutic targeting of KCC2 for disorders of neuronal hyperexcitability. Expert Opin Ther Targets 2020; 24:629-637. [PMID: 32336175 DOI: 10.1080/14728222.2020.1762174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Epilepsy is a common neurological disorder of neuronal hyperexcitability that begets recurrent and unprovoked seizures. The lack of a truly satisfactory pharmacotherapy for epilepsy highlights the clinical urgency for the discovery of new drug targets. To that end, targeting the electroneutral K+/Cl- cotransporter KCC2 has emerged as a novel therapeutic strategy for the treatment of epilepsy. AREAS COVERED We summarize the roles of KCC2 in the maintenance of synaptic inhibition and the evidence linking KCC2 dysfunction to epileptogenesis. We also discuss preclinical proof-of-principle studies that demonstrate that augmentation of KCC2 function can reduce seizure activity. Moreover, potential strategies to modulate KCC2 activity for therapeutic benefit are highlighted. EXPERT OPINION Although KCC2 is a promising drug target, questions remain before clinical translation. It is unclear whether increasing KCC2 activity can reverse epileptogenesis, the ultimate curative goal for epilepsy therapy that extends beyond seizure reduction. Furthermore, the potential adverse effects associated with increased KCC2 function have not been studied. Continued investigations into the neurobiology of KCC2 will help to translate promising preclinical insights into viable therapeutic avenues that leverage fundamental properties of KCC2 to treat medically intractable epilepsy and other disorders of failed synaptic inhibition with attendant neuronal hyperexcitability.
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Affiliation(s)
- Phan Q Duy
- Department of Neurosurgery, Yale University School of Medicine , New Haven, CT, USA.,Medical Scientist Training Program, Yale University School of Medicine , New Haven, CT, USA
| | - Miao He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School , Boston, MA, USA
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School , Boston, MA, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Yale University School of Medicine , New Haven, CT, USA.,Department of Genetics, Yale University School of Medicine , New Haven, CT, USA.,Departments of Pediatrics and Cellular & Molecular Physiology, Yale University School of Medicine , New Haven, CT, USA.,Yale-Rockefeller NIH Centers for Mendelian Genomics, Yale University , New Haven, CT, USA.,Yale Stem Cell Center, Yale School of Medicine , New Haven, CT, USA
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22
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Protein Degradome of Spinal Cord Injury: Biomarkers and Potential Therapeutic Targets. Mol Neurobiol 2020; 57:2702-2726. [PMID: 32328876 DOI: 10.1007/s12035-020-01916-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/31/2020] [Indexed: 12/13/2022]
Abstract
Degradomics is a proteomics sub-discipline whose goal is to identify and characterize protease-substrate repertoires. With the aim of deciphering and characterizing key signature breakdown products, degradomics emerged to define encryptic biomarker neoproteins specific to certain disease processes. Remarkable improvements in structural and analytical experimental methodologies as evident in research investigating cellular behavior in neuroscience and cancer have allowed the identification of specific degradomes, increasing our knowledge about proteases and their regulators and substrates along with their implications in health and disease. A physiologic balance between protein synthesis and degradation is sought with the activation of proteolytic enzymes such as calpains, caspases, cathepsins, and matrix metalloproteinases. Proteolysis is essential for development, growth, and regeneration; however, inappropriate and uncontrolled activation of the proteolytic system renders the diseased tissue susceptible to further neurotoxic processes. In this article, we aim to review the protease-substrate repertoires as well as emerging therapeutic interventions in spinal cord injury at the degradomic level. Several protease substrates and their breakdown products, essential for the neuronal structural integrity and functional capacity, have been characterized in neurotrauma including cytoskeletal proteins, neuronal extracellular matrix glycoproteins, cell junction proteins, and ion channels. Therefore, targeting exaggerated protease activity provides a potentially effective therapeutic approach in the management of protease-mediated neurotoxicity in reducing the extent of damage secondary to spinal cord injury.
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23
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Beverungen H, Klaszky SC, Klaszky M, Côté MP. Rehabilitation Decreases Spasticity by Restoring Chloride Homeostasis through the Brain-Derived Neurotrophic Factor-KCC2 Pathway after Spinal Cord Injury. J Neurotrauma 2020; 37:846-859. [PMID: 31578924 PMCID: PMC7071070 DOI: 10.1089/neu.2019.6526] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Activity-based therapy is routinely integrated in rehabilitation programs to facilitate functional recovery after spinal cord injury (SCI). Among its beneficial effects is a reduction of hyperreflexia and spasticity, which affects ∼75% of the SCI population. Unlike current anti-spastic pharmacological treatments, rehabilitation attenuates spastic symptoms without causing an active depression in spinal excitability, thus avoiding further interference with motor recovery. Understanding how activity-based therapies contribute to decrease spasticity is critical to identifying new pharmacological targets and to optimize rehabilitation programs. It was recently demonstrated that a decrease in the expression of KCC2, a neuronal Cl- extruder, contributes to the development spasticity in SCI rats. Although exercise can decrease spinal hyperexcitability and increase KCC2 expression on lumbar motoneurons after SCI, a causal effect remains to be established. Activity-dependent processes include an increase in brain-derived neurotrophic factor (BDNF) expression. Interestingly, BDNF is a regulator of KCC2 but also a potent modulator of spinal excitability. Therefore, we hypothesized that after SCI, the activity-dependent increase in KCC2 expression: 1) functionally contributes to reduce hyperreflexia, and 2) is regulated by BDNF. SCI rats chronically received VU0240551 (KCC2 blocker) or TrkB-IgG (BDNF scavenger) during the daily rehabilitation sessions and the frequency-dependent depression of the H-reflex, a monitor of hyperreflexia, was recorded 4 weeks post-injury. Our results suggest that the activity-dependent increase in KCC2 functionally contributes to H-reflex recovery and critically depends on BDNF activity. This study provides a new perspective in understanding how exercise impacts hyperreflexia by identifying the biological basis of the recovery of function.
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Affiliation(s)
- Henrike Beverungen
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Samantha Choyke Klaszky
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Michael Klaszky
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Marie-Pascale Côté
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
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24
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Tang BL. The Expanding Therapeutic Potential of Neuronal KCC2. Cells 2020; 9:E240. [PMID: 31963584 PMCID: PMC7016893 DOI: 10.3390/cells9010240] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/09/2020] [Accepted: 01/16/2020] [Indexed: 02/06/2023] Open
Abstract
Dysfunctions in GABAergic inhibitory neural transmission occur in neuronal injuries and neurological disorders. The potassium-chloride cotransporter 2 (KCC2, SLC12A5) is a key modulator of inhibitory GABAergic inputs in healthy adult neurons, as its chloride (Cl-) extruding activity underlies the hyperpolarizing reversal potential for GABAA receptor Cl- currents (EGABA). Manipulation of KCC2 levels or activity improve symptoms associated with epilepsy and neuropathy. Recent works have now indicated that pharmacological enhancement of KCC2 function could reactivate dormant relay circuits in an injured mouse's spinal cord, leading to functional recovery and the attenuation of neuronal abnormality and disease phenotype associated with a mouse model of Rett syndrome (RTT). KCC2 interacts with Huntingtin and is downregulated in Huntington's disease (HD), which contributed to GABAergic excitation and memory deficits in the R6/2 mouse HD model. Here, these recent advances are highlighted, which attest to KCC2's growing potential as a therapeutic target for neuropathological conditions resulting from dysfunctional inhibitory input.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore; ; Tel.: +65-6516-1040
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 119077, Singapore
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25
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Plantier V, Sanchez-Brualla I, Dingu N, Brocard C, Liabeuf S, Gackière F, Brocard F. Calpain fosters the hyperexcitability of motoneurons after spinal cord injury and leads to spasticity. eLife 2019; 8:e51404. [PMID: 31815668 PMCID: PMC6927741 DOI: 10.7554/elife.51404] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/08/2019] [Indexed: 12/12/2022] Open
Abstract
Up-regulation of the persistent sodium current (INaP) and down-regulation of the potassium/chloride extruder KCC2 lead to spasticity after spinal cord injury (SCI). We here identified calpain as the driver of the up- and down-regulation of INaP and KCC2, respectively, in neonatal rat lumbar motoneurons. Few days after SCI, neonatal rats developed behavioral signs of spasticity with the emergence of both hyperreflexia and abnormal involuntary muscle contractions on hindlimbs. At the same time, in vitro isolated lumbar spinal cords became hyperreflexive and displayed numerous spontaneous motor outputs. Calpain-I expression paralleled with a proteolysis of voltage-gated sodium (Nav) channels and KCC2. Acute inhibition of calpains reduced this proteolysis, restored the motoneuronal expression of Nav and KCC2, normalized INaP and KCC2 function, and curtailed spasticity. In sum, by up- and down-regulating INaP and KCC2, the calpain-mediated proteolysis of Nav and KCC2 drives the hyperexcitability of motoneurons which leads to spasticity after SCI.
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Affiliation(s)
- Vanessa Plantier
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
| | - Irene Sanchez-Brualla
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
| | - Nejada Dingu
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
| | - Cécile Brocard
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
| | - Sylvie Liabeuf
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
| | - Florian Gackière
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
| | - Frédéric Brocard
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRSMarseilleFrance
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Goutierre M, Al Awabdh S, Donneger F, François E, Gomez-Dominguez D, Irinopoulou T, Menendez de la Prida L, Poncer JC. KCC2 Regulates Neuronal Excitability and Hippocampal Activity via Interaction with Task-3 Channels. Cell Rep 2019; 28:91-103.e7. [PMID: 31269453 DOI: 10.1016/j.celrep.2019.06.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 04/18/2019] [Accepted: 05/30/2019] [Indexed: 10/26/2022] Open
Abstract
KCC2 regulates neuronal transmembrane chloride gradients and thereby controls GABA signaling in the brain. KCC2 downregulation is observed in numerous neurological and psychiatric disorders. Paradoxical, excitatory GABA signaling is usually assumed to contribute to abnormal network activity underlying the pathology. We tested this hypothesis and explored the functional impact of chronic KCC2 downregulation in the rat dentate gyrus. Although the reversal potential of GABAA receptor currents is depolarized in KCC2 knockdown neurons, this shift is compensated by depolarization of the resting membrane potential. This reflects downregulation of leak potassium currents. We show KCC2 interacts with Task-3 (KCNK9) channels and is required for their membrane expression. Increased neuronal excitability upon KCC2 suppression altered dentate gyrus rhythmogenesis, which could be normalized by chemogenetic hyperpolarization. Our data reveal KCC2 downregulation engages complex synaptic and cellular alterations beyond GABA signaling that perturb network activity thus offering additional targets for therapeutic intervention.
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Affiliation(s)
- Marie Goutierre
- INSERM UMR-S 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France
| | - Sana Al Awabdh
- INSERM UMR-S 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France
| | - Florian Donneger
- INSERM UMR-S 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France
| | - Emeline François
- INSERM UMR-S 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France
| | - Daniel Gomez-Dominguez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28002, Spain
| | - Theano Irinopoulou
- INSERM UMR-S 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France
| | | | - Jean Christophe Poncer
- INSERM UMR-S 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France.
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27
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Spinal Cord Stimulation for Pain Treatment After Spinal Cord Injury. Neurosci Bull 2018; 35:527-539. [PMID: 30560438 DOI: 10.1007/s12264-018-0320-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 08/11/2018] [Indexed: 12/30/2022] Open
Abstract
In addition to restoration of bladder, bowel, and motor functions, alleviating the accompanying debilitating pain is equally important for improving the quality of life of patients with spinal cord injury (SCI). Currently, however, the treatment of chronic pain after SCI remains a largely unmet need. Electrical spinal cord stimulation (SCS) has been used to manage a variety of chronic pain conditions that are refractory to pharmacotherapy. Yet, its efficacy, benefit profiles, and mechanisms of action in SCI pain remain elusive, due to limited research, methodological weaknesses in previous clinical studies, and a lack of mechanistic exploration of SCS for SCI pain control. We aim to review recent studies and outline the therapeutic potential of different SCS paradigms for traumatic SCI pain. We begin with an overview of its manifestations, classification, potential underlying etiology, and current challenges for its treatment. The clinical evidence for using SCS in SCI pain is then reviewed. Finally, future perspectives of pre-clinical research and clinical study of SCS for SCI pain treatment are discussed.
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