1
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Kovyazina IV, Khamidullina AA. Muscarinic Cholinoreceptors in Skeletal Muscle: Localization and Functional Role. Acta Naturae 2023; 15:44-55. [PMID: 38234599 PMCID: PMC10790362 DOI: 10.32607/actanaturae.25259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 09/24/2023] [Indexed: 01/19/2024] Open
Abstract
The review focuses on the modern concepts of the functions of muscarinic cholinoreceptors in skeletal muscles, particularly, in neuromuscular contacts, and that of the signaling pathways associated with the activation of various subtypes of muscarinic receptors in the skeletal muscles of cold-blooded and warm-blooded animals. Despite the long history of research into the involvement of muscarinic receptors in the modulation of neuromuscular transmission, many aspects of such regulation and the associated intracellular mechanisms remain unclear. Now it is obvious that the functions of muscarinic receptors in skeletal muscle are not limited to the autoregulation of neurosecretion from motor nerve endings but also extend to the development and morphological rearrangements of the synaptic apparatus, coordinating them with the degree of activity. The review discusses various approaches to the study of the functions of muscarinic receptors in motor synapses, as well as the problems arising when interpreting experimental data. The final part of the review is devoted to an analysis of some of the intracellular mechanisms and signaling pathways that mediate the effects of muscarinic agents on neuromuscular transmission.
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Affiliation(s)
- I. V. Kovyazina
- Kazan State Medical University, Kazan, 420012 Russian Federation
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Kazan, 420111 Russian Federation
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2
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Lépine S, Castellanos-Montiel MJ, Durcan TM. TDP-43 dysregulation and neuromuscular junction disruption in amyotrophic lateral sclerosis. Transl Neurodegener 2022; 11:56. [PMID: 36575535 PMCID: PMC9793560 DOI: 10.1186/s40035-022-00331-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/29/2022] [Indexed: 12/28/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease characterized by upper and lower motor neuron (MN) loss with a signature feature of cytoplasmic aggregates containing TDP-43, which are detected in nearly all patients. Mutations in the gene that encodes TDP-43 (TARBDP) are known to result in both familial and sporadic ALS. In ALS, disruption of neuromuscular junctions (NMJs) constitutes a critical event in disease pathogenesis, leading to denervation atrophy, motor impairments and disability. Morphological defects and impaired synaptic transmission at NMJs have been reported in several TDP-43 animal models and in vitro, linking TDP-43 dysregulation to the loss of NMJ integrity in ALS. Through the lens of the dying-back and dying-forward hypotheses of ALS, this review discusses the roles of TDP-43 related to synaptic function, with a focus on the potential molecular mechanisms occurring within MNs, skeletal muscles and glial cells that may contribute to NMJ disruption in ALS.
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Affiliation(s)
- Sarah Lépine
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada ,grid.14709.3b0000 0004 1936 8649Faculty of Medicine and Health Sciences, McGill University, 3605 De La Montagne, Montreal, QC H3G 2M1 Canada
| | - Maria José Castellanos-Montiel
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
| | - Thomas Martin Durcan
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
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3
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Perez-Gonzalez AP, Provost F, Rousse I, Piovesana R, Benzina O, Darabid H, Lamoureux B, Wang YS, Arbour D, Robitaille R. Functional adaptation of glial cells at neuromuscular junctions in response to injury. Glia 2022; 70:1605-1629. [PMID: 35474470 PMCID: PMC9543218 DOI: 10.1002/glia.24184] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 12/04/2022]
Abstract
Synaptic elements from neuromuscular junctions (NMJs) undergo massive morphological and functional changes upon nerve injury. While morphological changes of NMJ‐associated glia in response to injury has been investigated, their functional properties remain elusive. Perisynaptic Schwann cells (PSCs), glial cells at the NMJ, are essential for NMJ maintenance and repair, and are involved in synaptic efficacy and plasticity. Importantly, these functions are regulated by PSCs ability to detect synaptic transmission through, notably, muscarinic (mAChRs) and purinergic receptors' activation. Using Ca2+ imaging and electrophysiological recordings of synaptic transmission at the mouse NMJ, we investigated PSC receptors activation following denervation and during reinnervation in adults and at denervated NMJs in an ALS mouse model (SOD1G37R). We observed reduced PSCs mAChR‐mediated Ca2+ responses at denervated and reinnervating NMJs. Importantly, PSC phenotypes during denervation and reinnervation were distinct than the one observed during NMJ maturation. At denervated NMJs, exogenous activation of mAChRs greatly diminished galectin‐3 expression, a glial marker of phagocytosis. PSCs Ca2+ responses at reinnervating NMJs did not correlate with the number of innervating axons or process extensions. Interestingly, we observed an extended period of reduced PSC mAChRs activation after the injury (up to 60 days), suggesting a glial memory of injury. PSCs associated with denervated NMJs in an ALS model (SOD1G37R mice) did not show any muscarinic adaptation, a phenotype incompatible with NMJ repair. Understanding functional mechanisms that underlie this glial response to injury may contribute to favor complete NMJ and motor recovery.
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Affiliation(s)
- Anna P Perez-Gonzalez
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Frédéric Provost
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Isabelle Rousse
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Roberta Piovesana
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Ouafa Benzina
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Houssam Darabid
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Benoit Lamoureux
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Yu Shi Wang
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Danielle Arbour
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Richard Robitaille
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada.,Centre Interdisciplinaire de Recherche sur le Cerveau et l'apprentissage, Montréal, Québec, Canada
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4
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Machado-Santos AR, Loureiro-Campos E, Patrício P, Araújo B, Alves ND, Mateus-Pinheiro A, Correia JS, Morais M, Bessa JM, Sousa N, Rodrigues AJ, Oliveira JF, Pinto L. Beyond New Neurons in the Adult Hippocampus: Imipramine Acts as a Pro-Astrogliogenic Factor and Rescues Cognitive Impairments Induced by Stress Exposure. Cells 2022; 11:cells11030390. [PMID: 35159199 PMCID: PMC8834148 DOI: 10.3390/cells11030390] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/13/2022] [Accepted: 01/21/2022] [Indexed: 02/06/2023] Open
Abstract
Depression is a prevalent, socially burdensome disease. Different studies have demonstrated the important role of astrocytes in the pathophysiology of depression as modulators of neurotransmission and neurovascular coupling. This is evidenced by astrocyte impairments observed in brains of depressed patients and the appearance of depressive-like behaviors upon astrocytic dysfunctions in animal models. However, little is known about the importance of de novo generated astrocytes in the mammalian brain and in particular its possible involvement in the precipitation of depression and in the therapeutic actions of current antidepressants (ADs). Therefore, we studied the modulation of astrocytes and adult astrogliogenesis in the hippocampal dentate gyrus (DG) of rats exposed to an unpredictable chronic mild stress (uCMS) protocol, untreated and treated for two weeks with antidepressants—fluoxetine and imipramine. Our results show that adult astrogliogenesis in the DG is modulated by stress and imipramine. This study reveals that distinct classes of ADs impact differently in the astrogliogenic process, showing different cellular mechanisms relevant to the recovery from behavioral deficits induced by chronic stress exposure. As such, in addition to those resident, the newborn astrocytes in the hippocampal DG might also be promising therapeutic targets for future therapies in the neuropsychiatric field.
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Affiliation(s)
- Ana R Machado-Santos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Eduardo Loureiro-Campos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Patrício
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Bruna Araújo
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Dinis Alves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - António Mateus-Pinheiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Joana Sofia Correia
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Mónica Morais
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - João M Bessa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Ana J Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - João Filipe Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, Campus of IPCA, 4750-810 Barcelos, Portugal
| | - Luísa Pinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
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5
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Fuertes-Alvarez S, Izeta A. Terminal Schwann Cell Aging: Implications for Age-Associated Neuromuscular Dysfunction. Aging Dis 2021; 12:494-514. [PMID: 33815879 PMCID: PMC7990373 DOI: 10.14336/ad.2020.0708] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/08/2020] [Indexed: 12/11/2022] Open
Abstract
Action potential is transmitted to muscle fibers through specialized synaptic interfaces called neuromuscular junctions (NMJs). These structures are capped by terminal Schwann cells (tSCs), which play essential roles during formation and maintenance of the NMJ. tSCs are implicated in the correct communication between nerves and muscles, and in reinnervation upon injury. During aging, loss of muscle mass and strength (sarcopenia and dynapenia) are due, at least in part, to the progressive loss of contacts between muscle fibers and nerves. Despite the important role of tSCs in NMJ function, very little is known on their implication in the NMJ-aging process and in age-associated denervation. This review summarizes the current knowledge about the implication of tSCs in the age-associated degeneration of NMJs. We also speculate on the possible mechanisms underlying the observed phenotypes.
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Affiliation(s)
- Sandra Fuertes-Alvarez
- 1Biodonostia, Tissue Engineering Group, Paseo Dr. Begiristain, s/n, San Sebastian 20014, Spain
| | - Ander Izeta
- 1Biodonostia, Tissue Engineering Group, Paseo Dr. Begiristain, s/n, San Sebastian 20014, Spain.,2Tecnun-University of Navarra, School of Engineering, Department of Biomedical Engineering and Science, Paseo Mikeletegi, 48, San Sebastian 20009, Spain
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6
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Properties of Glial Cell at the Neuromuscular Junction Are Incompatible with Synaptic Repair in the SOD1G37R ALS Mouse Model. J Neurosci 2020; 40:7759-7777. [PMID: 32859714 DOI: 10.1523/jneurosci.1748-18.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting motoneurons (MNs) in a motor-unit (MU)-dependent manner. Glial dysfunction contributes to numerous aspects of the disease. At the neuromuscular junction (NMJ), early alterations in perisynaptic Schwann cell (PSC), glial cells at this synapse, may impact their ability to regulate NMJ stability and repair. Indeed, muscarinic receptors (mAChRs) regulate the repair phenotype of PSCs and are overactivated at disease-resistant NMJs [soleus muscle (SOL)] in SOD1G37R mice. However, it remains unknown whether this is the case at disease-vulnerable NMJs and whether it translates into an impairment of PSC-dependent repair mechanisms. We used SOL and sternomastoid (STM) muscles from SOD1G37R mice and performed Ca2+-imaging to monitor PSC activity and used immunohistochemistry to analyze their repair and phagocytic properties. We show that PSC mAChR-dependent activity was transiently increased at disease-vulnerable NMJs (STM muscle). Furthermore, PSCs from both muscles extended disorganized processes from denervated NMJs and failed to initiate or guide nerve terminal sprouts at disease-vulnerable NMJs, a phenomenon essential for compensatory reinnervation. This was accompanied by a failure of numerous PSCs to upregulate galectin-3 (MAC-2), a marker of glial axonal debris phagocytosis, on NMJ denervation in SOD1 mice. Finally, differences in these PSC-dependent NMJ repair mechanisms were MU type dependent, thus reflecting MU vulnerability in ALS. Together, these results reveal that neuron-glia communication is ubiquitously altered at the NMJ in ALS. This appears to prevent PSCs from adopting a repair phenotype, resulting in a maladapted response to denervation at the NMJ in ALS.SIGNIFICANCE STATEMENT Understanding how the complex interplay between neurons and glial cells ultimately lead to the degeneration of motor neurons and loss of motor function is a fundamental question to comprehend amyotrophic lateral sclerosis (ALS). An early and persistent alteration of glial cell activity takes place at the neuromuscular junction (NMJ), the output of motor neurons, but its impact on NMJ repair remains unknown. Here, we reveal that glial cells at disease-vulnerable NMJs often fail to guide compensatory nerve terminal sprouts and to adopt a phagocytic phenotype on denervated NMJs in SOD1G37R mice. These results show that glial cells at the NMJ elaborate an inappropriate response to NMJ degeneration in a manner that reflects motor-unit (MU) vulnerability and potentially impairs compensatory reinnervation.
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7
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Santosa KB, Keane AM, Jablonka-Shariff A, Vannucci B, Snyder-Warwick AK. Clinical relevance of terminal Schwann cells: An overlooked component of the neuromuscular junction. J Neurosci Res 2018; 96:1125-1135. [PMID: 29536564 PMCID: PMC6292684 DOI: 10.1002/jnr.24231] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/30/2017] [Accepted: 02/09/2018] [Indexed: 12/13/2022]
Abstract
The terminal Schwann cell (tSC), a type of nonmyelinating Schwann cell, is a significant yet relatively understudied component of the neuromuscular junction. In addition to reviewing the role tSCs play on formation, maintenance, and remodeling of the synapse, we review studies that implicate tSCs in neuromuscular diseases including spinal muscular atrophy, Miller-Fisher syndrome, and amyotrophic lateral sclerosis, among others. We also discuss the importance of these cells on degeneration and regeneration after nerve injury. Knowledge of tSC biology may improve our understanding of disease pathogenesis and help us identify new and innovative therapeutic strategies for the many patients who suffer from neuromuscular disorders and nerve injuries.
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Affiliation(s)
- Katherine B. Santosa
- Postdoctoral Research Fellow, Division of Plastic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO
| | - Alexandra M. Keane
- Medical Student, Washington University School of Medicine, St. Louis, MO
| | - Albina Jablonka-Shariff
- Research Scientist, Division of Plastic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO
| | - Bianca Vannucci
- Medical Student, Washington University School of Medicine, St. Louis, MO
| | - Alison K. Snyder-Warwick
- Assistant Professor, Division of Plastic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO
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8
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Abstract
The schwann cells of the peripheral nervous system are indispensable for the formation, maintenance, and modulation of synapses over the life cycle. They not only recognize neuron-glia signaling molecules, but also secrete gliotransmitters. Through these processes, they regulate neuronal excitability and thus the release of neurotransmitters from the nerve terminal at the neuromuscular junction. Gliotransmitters strongly affect nerve communication, and their secretion is mainly triggered by synchronized Ca2+ signaling, implicating Ca2+ waves in synapse function. Reciprocally, neurotransmitters released during synaptic activity can evoke increases in intracellular Ca2+ levels. A reconsideration of the interplay between the two main types of cells in the nervous system is due, as the concept of nervous system activity comprising only neuron-neuron and neuron-muscle action has become untenable. A more precise understanding of the roles of schwann cells in nerve-muscle signaling is required.
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Affiliation(s)
- Sujin Hyung
- Department of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Shilim-dong, Gwanak-gu, Seoul, 08826, Korea
- BK21 Plus Transformative Training Program for Creative Mechanical and Aerospace Engineers, Seoul National University, San 56-1, Shilim-dong, Gwanak-gu, Seoul, 08826, Korea
| | - Kyuhwan Jung
- Graduate Program of Nano Science and Technology, Graduate School of Yonsei University, 50-1 Yonsei Ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Sung-Rae Cho
- Graduate Program of Nano Science and Technology, Graduate School of Yonsei University, 50-1 Yonsei Ro, Seodaemun-gu, Seoul, 03722, Korea
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, 50-1 Yonsei Ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Noo Li Jeon
- Department of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Shilim-dong, Gwanak-gu, Seoul, 08826, Korea
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9
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Arbour D, Vande Velde C, Robitaille R. New perspectives on amyotrophic lateral sclerosis: the role of glial cells at the neuromuscular junction. J Physiol 2016; 595:647-661. [PMID: 27633977 DOI: 10.1113/jp270213] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/12/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease leading to the death of motor neurons (MNs). It is also recognized as a non-cell autonomous disease where glial cells in the CNS are involved in its pathogenesis and progression. However, although denervation of neuromuscular junctions (NMJs) represents an early and major event in ALS, the importance of glial cells at this synapse receives little attention. An interesting possibility is that altered relationships between glial cells and MNs in the spinal cord in ALS may also take place at the NMJ. Perisynaptic Schwann cells (PSCs), which are glial cells at the NMJ, show great morphological and functional adaptability to ensure NMJ stability, maintenance and repair. More specifically, PSCs change their properties according to the state of innervation. Hence, abnormal changes or lack of changes can have detrimental effects on NMJs in ALS. This review will provide an overview of known and hypothesized interactions between MN nerve terminals and PSCs at NMJs during development, aging and ALS-induced denervation. These neuron-PSC interactions may be crucial to the understanding of how degenerative changes begin and progress at NMJs in ALS, and represent a novel therapeutic target.
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Affiliation(s)
- Danielle Arbour
- Département de neurosciences, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Groupe de recherche sur le système nerveux central, Université de Montréal, Montréal, Québec, Canada, H3C 3J7
| | - Christine Vande Velde
- Département de neurosciences, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Groupe de recherche sur le système nerveux central, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada, H2X 0A9
| | - Richard Robitaille
- Département de neurosciences, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Groupe de recherche sur le système nerveux central, Université de Montréal, Montréal, Québec, Canada, H3C 3J7
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10
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Ko CP, Robitaille R. Perisynaptic Schwann Cells at the Neuromuscular Synapse: Adaptable, Multitasking Glial Cells. Cold Spring Harb Perspect Biol 2015; 7:a020503. [PMID: 26430218 PMCID: PMC4588062 DOI: 10.1101/cshperspect.a020503] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The neuromuscular junction (NMJ) is engineered to be a highly reliable synapse to carry the control of the motor commands of the nervous system over the muscles. Its development, organization, and synaptic properties are highly structured and regulated to support such reliability and efficacy. Yet, the NMJ is also highly plastic, able to react to injury and adapt to changes. This balance between structural stability and synaptic efficacy on one hand and structural plasticity and repair on another hand is made possible by the intricate regulation of perisynaptic Schwann cells, glial cells at this synapse. They regulate both the efficacy and structural plasticity of the NMJ in a dynamic, bidirectional manner owing to their ability to decode synaptic transmission and by their interactions via trophic-related factors.
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Affiliation(s)
- Chien-Ping Ko
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-2520
| | - Richard Robitaille
- Département de Neurosciences, Université de Montréal, Montréal, Québec H3C 3J7, Canada Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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11
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Plasticity of Neuron-Glial Transmission: Equipping Glia for Long-Term Integration of Network Activity. Neural Plast 2015; 2015:765792. [PMID: 26339509 PMCID: PMC4539116 DOI: 10.1155/2015/765792] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/11/2015] [Indexed: 01/28/2023] Open
Abstract
The capacity of synaptic networks to express activity-dependent changes in strength and connectivity is essential for learning and memory processes. In recent years, glial cells (most notably astrocytes) have been recognized as active participants in the modulation of synaptic transmission and synaptic plasticity, implicating these electrically nonexcitable cells in information processing in the brain. While the concept of bidirectional communication between neurons and glia and the mechanisms by which gliotransmission can modulate neuronal function are well established, less attention has been focussed on the computational potential of neuron-glial transmission itself. In particular, whether neuron-glial transmission is itself subject to activity-dependent plasticity and what the computational properties of such plasticity might be has not been explored in detail. In this review, we summarize current examples of plasticity in neuron-glial transmission, in many brain regions and neurotransmitter pathways. We argue that induction of glial plasticity typically requires repetitive neuronal firing over long time periods (minutes-hours) rather than the short-lived, stereotyped trigger typical of canonical long-term potentiation. We speculate that this equips glia with a mechanism for monitoring average firing rates in the synaptic network, which is suited to the longer term roles proposed for astrocytes in neurophysiology.
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12
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Sibille J, Zapata J, Teillon J, Rouach N. Astroglial calcium signaling displays short-term plasticity and adjusts synaptic efficacy. Front Cell Neurosci 2015; 9:189. [PMID: 26074766 PMCID: PMC4444818 DOI: 10.3389/fncel.2015.00189] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/29/2015] [Indexed: 01/14/2023] Open
Abstract
Astrocytes are dynamic signaling brain elements able to sense neuronal inputs and to respond by complex calcium signals, which are thought to represent their excitability. Such signaling has been proposed to modulate, or not, neuronal activities ranging from basal synaptic transmission to epileptiform discharges. However, whether calcium signaling in astrocytes exhibits activity-dependent changes and acutely modulates short-term synaptic plasticity is currently unclear. We here show, using dual recordings of astroglial calcium signals and synaptic transmission, that calcium signaling in astrocytes displays, concomitantly to excitatory synapses, short-term plasticity in response to prolonged repetitive and tetanic stimulations of Schaffer collaterals. We also found that acute inhibition of calcium signaling in astrocytes by intracellular calcium chelation rapidly potentiates excitatory synaptic transmission and short-term plasticity of Shaffer collateral CA1 synapses, i.e., paired-pulse facilitation and responses to tetanic and prolonged repetitive stimulation. These data reveal that calcium signaling of astrocytes is plastic and down-regulates basal transmission and short-term plasticity of hippocampal CA1 glutamatergic synapses.
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Affiliation(s)
- Jérémie Sibille
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France ; Université Paris Diderot, Sorbonne Paris Cité Paris, France
| | - Jonathan Zapata
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France
| | - Jérémie Teillon
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France
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13
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Early and persistent abnormal decoding by glial cells at the neuromuscular junction in an ALS model. J Neurosci 2015; 35:688-706. [PMID: 25589763 DOI: 10.1523/jneurosci.1379-14.2015] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a late-onset neuromuscular disease characterized by progressive loss of motor neurons (MNs) preceded by neuromuscular junction (NMJ) denervation. Despite the importance of NMJ denervation in ALS, the mechanisms involved remain unexplored and ill defined. The contribution of glial cells in the disease has been highlighted, including axonal Schwann cell activation that precedes the decline of motor function and the onset of hindlimb paralysis. Because NMJ denervation occurs early in the process and that perisynaptic Schwann cells (PSCs), glial cells at the NMJ, regulate morphological stability, integrity, and repair of the NMJ, one could predict that PSC functions would be altered even before denervation, contributing to NMJ malfunctions. We tested this possibility using a slowly progressive model of ALS (SOD1(G37R) mice). We observed a normal NMJ organization at a presymptomatic stage of ALS (120 d), but PSC detection of endogenous synaptic activity revealed by intracellular Ca(2+) changes was enhanced compared with their wild-type littermates. This inappropriate PSC decoding ability was associated with an increased level of neurotransmitter release and dependent on intrinsic glial properties related to enhanced muscarinic receptor activation. The alteration of PSC muscarinic receptor functions also persists during the preonset stage of the disease and became dependent on MN vulnerability with age. Together, these results suggest that PSC properties are altered in the disease process in a manner that would be detrimental for NMJ repair. The impairments of PSC functions may contribute to NMJ dysfunction and ALS pathogenesis.
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14
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Mitterauer BJ. Self-Structuring of Motile Astrocytic Processes within the Network of a Single Astrocyte. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/abb.2015.612074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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De Pittà M, Volman V, Berry H, Parpura V, Volterra A, Ben-Jacob E. Computational quest for understanding the role of astrocyte signaling in synaptic transmission and plasticity. Front Comput Neurosci 2012; 6:98. [PMID: 23267326 PMCID: PMC3528083 DOI: 10.3389/fncom.2012.00098] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 12/06/2012] [Indexed: 01/08/2023] Open
Abstract
The complexity of the signaling network that underlies astrocyte-synapse interactions may seem discouraging when tackled from a theoretical perspective. Computational modeling is challenged by the fact that many details remain hitherto unknown and conventional approaches to describe synaptic function are unsuitable to explain experimental observations when astrocytic signaling is taken into account. Supported by experimental evidence is the possibility that astrocytes perform genuine information processing by means of their calcium signaling and are players in the physiological setting of the basal tone of synaptic transmission. Here we consider the plausibility of this scenario from a theoretical perspective, focusing on the modulation of synaptic release probability by the astrocyte and its implications on synaptic plasticity. The analysis of the signaling pathways underlying such modulation refines our notion of tripartite synapse and has profound implications on our understanding of brain function.
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Affiliation(s)
- Maurizio De Pittà
- School of Physics and Astronomy, Tel Aviv University Ramat Aviv, Israel
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16
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Xie AX, Sun MY, Murphy T, Lauderdale K, Tiglao E, Fiacco TA. Bidirectional scaling of astrocytic metabotropic glutamate receptor signaling following long-term changes in neuronal firing rates. PLoS One 2012; 7:e49637. [PMID: 23166735 PMCID: PMC3499417 DOI: 10.1371/journal.pone.0049637] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/16/2012] [Indexed: 11/19/2022] Open
Abstract
Very little is known about the ability of astrocytic receptors to exhibit plasticity as a result of changes in neuronal activity. Here we provide evidence for bidirectional scaling of astrocytic group I metabotropic glutamate receptor signaling in acute mouse hippocampal slices following long-term changes in neuronal firing rates. Plasticity of astrocytic mGluRs was measured by recording spontaneous and evoked Ca2+ elevations in both astrocytic somata and processes. An exogenous astrocytic Gq G protein-coupled receptor was resistant to scaling, suggesting that the alterations in astrocyte Ca2+ signaling result from changes in activity of the surface mGluRs rather than a change in intracellular G protein signaling molecules. These findings suggest that astrocytes actively detect shifts in neuronal firing rates and adjust their receptor signaling accordingly. This type of long-term plasticity in astrocytes resembles neuronal homeostatic plasticity and might be important to ensure an optimal or expected level of input from neurons.
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Affiliation(s)
- Alison X. Xie
- Graduate Program in Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Min-Yu Sun
- Graduate Program in Cellular, Molecular, and Developmental Biology, University of California Riverside, Riverside, California, United States of America
| | - Thomas Murphy
- Graduate Program in Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Kelli Lauderdale
- Graduate Program in Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Elizabeth Tiglao
- Undergraduate Neuroscience Major, University of California Riverside, Riverside, California, United States of America
| | - Todd A. Fiacco
- Department of Cell Biology and Neuroscience and Center for Glial-Neuronal Interactions, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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17
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Neuron-glia interactions: the roles of Schwann cells in neuromuscular synapse formation and function. Biosci Rep 2012; 31:295-302. [PMID: 21517783 DOI: 10.1042/bsr20100107] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The NMJ (neuromuscular junction) serves as the ultimate output of the motor neurons. The NMJ is composed of a presynaptic nerve terminal, a postsynaptic muscle and perisynaptic glial cells. Emerging evidence has also demonstrated an existence of perisynaptic fibroblast-like cells at the NMJ. In this review, we discuss the importance of Schwann cells, the glial component of the NMJ, in the formation and function of the NMJ. During development, Schwann cells are closely associated with presynaptic nerve terminals and are required for the maintenance of the developing NMJ. After the establishment of the NMJ, Schwann cells actively modulate synaptic activity. Schwann cells also play critical roles in regeneration of the NMJ after nerve injury. Thus, Schwann cells are indispensable for formation and function of the NMJ. Further examination of the interplay among Schwann cells, the nerve and the muscle will provide insights into a better understanding of mechanisms underlying neuromuscular synapse formation and function.
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18
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Astrocytes are endogenous regulators of basal transmission at central synapses. Cell 2011; 146:785-98. [PMID: 21855979 DOI: 10.1016/j.cell.2011.07.022] [Citation(s) in RCA: 445] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 05/09/2011] [Accepted: 07/09/2011] [Indexed: 11/22/2022]
Abstract
Basal synaptic transmission involves the release of neurotransmitters at individual synapses in response to a single action potential. Recent discoveries show that astrocytes modulate the activity of neuronal networks upon sustained and intense synaptic activity. However, their ability to regulate basal synaptic transmission remains ill defined and controversial. Here, we show that astrocytes in the hippocampal CA1 region detect synaptic activity induced by single-synaptic stimulation. Astrocyte activation occurs at functional compartments found along astrocytic processes and involves metabotropic glutamate subtype 5 receptors. In response, astrocytes increase basal synaptic transmission, as revealed by the blockade of their activity with a Ca(2+) chelator. Astrocytic modulation of basal synaptic transmission is mediated by the release of purines and the activation of presynaptic A(2A) receptors by adenosine. Our work uncovers an essential role for astrocytes in the regulation of elementary synaptic communication and provides insight into fundamental aspects of brain function.
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19
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Johnstone VPA, Raymond CR. A protein synthesis and nitric oxide-dependent presynaptic enhancement in persistent forms of long-term potentiation. Learn Mem 2011; 18:625-33. [PMID: 21933902 DOI: 10.1101/lm.2245911] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Long-term potentiation (LTP) is an important process underlying learning and memory in the brain. At CA3-CA1 synapses in the hippocampus, three discrete forms of LTP (LTP1, 2, and 3) can be differentiated on the basis of maintenance and induction mechanisms. However, the relative roles of pre- and post-synaptic expression mechanisms in LTP1, 2, and 3 are unknown. Neurotransmitter release in the expression of LTP1, 2, and 3 was measured via FM 1-43 destaining from CA3 terminals in hippocampal slices from male Wistar rats (7-8 wk). No difference in vesicle turnover rate was observed for LTP1 up to 160 min following induction by one train of theta-burst stimulation (1TBS). A presynaptic enhancement was found for LTP2 at 160 min after induction by 4TBS, and for LTP3 at both 80 and 160 min after induction by 8TBS. Inhibition of nitric oxide (NO) signaling blocked both LTP2 and LTP3 maintenance and the associated enhanced release. LTP2 maintenance and its presynaptic expression were dependent on protein synthesis, but not gene transcription. LTP3 maintenance was dependent on both translation and transcription, but like LTP2, the enhanced release only required translation. These data considerably strengthen the mechanistic separation of LTP1, 2, and 3, supporting a model of multiple, discrete forms of LTP at CA3-CA1 synapses rather than different temporal phases.
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Affiliation(s)
- Victoria P A Johnstone
- Department of Neuroscience, The John Curtin School of Medical Research & Eccles Institute of Neuroscience, The Australian National University, Canberra ACT 0200, Australia
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20
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Honsek SD, Walz C, Kafitz KW, Rose CR. Astrocyte calcium signals at Schaffer collateral to CA1 pyramidal cell synapses correlate with the number of activated synapses but not with synaptic strength. Hippocampus 2010; 22:29-42. [DOI: 10.1002/hipo.20843] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2010] [Indexed: 11/08/2022]
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21
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Perisynaptic glia discriminate patterns of motor nerve activity and influence plasticity at the neuromuscular junction. J Neurosci 2010; 30:11870-82. [PMID: 20810906 DOI: 10.1523/jneurosci.3165-10.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the nervous system, the induction of plasticity is coded by patterns of synaptic activity. Glial cells are now recognized as dynamic partners in a wide variety of brain functions, including the induction and modulation of various forms of synaptic plasticity. However, it appears that glial cells are usually activated by stereotyped, sustained neuronal activity, and little attention has been given to more subtle changes in the patterns of synaptic activation. To this end, we used the mouse neuromuscular junction as a simple and useful model to study glial modulation of synaptic plasticity. We used two patterns of motor nerve stimulation that mimic endogenous motor-neuronal activity. A continuous stimulation induced a post-tetanic potentiation and a phasic Ca(2+) response in perisynaptic Schwann cells (PSCs), glial cells at this synapse. A bursting pattern of activity induced a post-tetanic depression and oscillatory Ca(2+) responses in PSCs. The different Ca(2+) responses in PSCs indicate that they decode the pattern of synaptic activity. Furthermore, the chelation of glial Ca(2+) impaired the production of the sustained plasticity events indicating that PSCs govern the outcome of synaptic plasticity. The mechanisms involved were studied using direct photo-activation of PSCs with caged Ca(2+) that mimicked endogenous plasticity. Using specific pharmacology and transgenic knock-out animals for adenosine receptors, we showed that the sustained depression was mediated by A1 receptors while the sustained potentiation is mediated by A(2A) receptors. These results demonstrate that glial cells decode the pattern of synaptic activity and subsequently provide bidirectional feedback to synapses.
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22
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Synapse-glia interactions are governed by synaptic and intrinsic glial properties. Neuroscience 2010; 167:621-32. [PMID: 20188148 DOI: 10.1016/j.neuroscience.2010.02.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 01/30/2010] [Accepted: 02/16/2010] [Indexed: 11/24/2022]
Abstract
It is believed that glial cell activation and their interactions with synapses are predominantly dependent upon the characteristics of synaptic activity and the level of transmitter release. Because synaptic properties vary from one type of synapse to another, synapse-glia interactions should differ accordingly. The goal of this work was to examine how glial cell activation is dependent upon the properties of their respective synapses as well as the level of synaptic activity. We contrasted Ca(2+) responses of perisynaptic Schwann cells (PSCs) at neuromuscular junctions (NMJs) with different synaptic properties; the slow-twitch soleus (SOL) and the fast-twitch levator auris longus (LAL) muscles. Amplitude of PSC Ca(2+) responses elicited by repeated motor nerve stimulation at 40, 50 and 100 Hz were larger and their kinetics faster at LAL NMJs and this, at all frequencies examined. In addition, a greater number of PSCs per NMJ was activated by sustained synaptic transmission at NMJs of LAL in comparison to SOL. Differences in PSC activation could not be explained solely by differences in levels of transmitter release but also by intrinsic PSC properties since increasing transmitter release with tetraethylammonium chloride (TEA) did not increase their responsiveness. As a whole, these results indicate that PSC responsiveness at NMJs of slow- and fast-twitch muscles differ not only according to the level of activity of their synaptic partner but also in accordance with inherent glial properties.
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