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Mantilla CB, Ermilov LG, Greising SM, Gransee HM, Zhan WZ, Sieck GC. Electrophysiological effects of BDNF and TrkB signaling at type-identified diaphragm neuromuscular junctions. J Neurophysiol 2023; 129:781-792. [PMID: 36883761 PMCID: PMC10069962 DOI: 10.1152/jn.00015.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023] Open
Abstract
Previous studies show that synaptic quantal release decreases during repetitive stimulation, i.e., synaptic depression. Neurotrophin brain-derived neurotrophic factor (BDNF) enhances neuromuscular transmission via activation of tropomyosin-related kinase receptor B (TrkB). We hypothesized that BDNF mitigates synaptic depression at the neuromuscular junction and that the effect is more pronounced at type IIx and/or IIb fibers compared to type I or IIa fibers given the more rapid reduction in docked synaptic vesicles with repetitive stimulation. Rat phrenic nerve-diaphragm muscle preparations were used to determine the effect of BDNF on synaptic quantal release during repetitive stimulation at 50 Hz. An ∼40% decline in quantal release was observed during each 330-ms duration train of nerve stimulation (intratrain synaptic depression), and this intratrain decline was observed across repetitive trains (20 trains at 1/s repeated every 5 min for 30 min for 6 sets). BDNF treatment significantly enhanced quantal release at all fiber types (P < 0.001). BDNF treatment did not change release probability within a stimulation set but enhanced synaptic vesicle replenishment between sets. In agreement, synaptic vesicle cycling (measured using FM4-64 fluorescence uptake) was increased following BDNF [or neurotrophin-4 (NT-4)] treatment (∼40%; P < 0.05). Conversely, inhibiting BDNF/TrkB signaling with the tyrosine kinase inhibitor K252a and TrkB-IgG (which quenches endogenous BDNF or NT-4) decreased FM4-64 uptake (∼34% across fiber types; P < 0.05). The effects of BDNF were generally similar across all fiber types. We conclude that BDNF/TrkB signaling acutely enhances presynaptic quantal release and thereby may serve to mitigate synaptic depression and maintain neuromuscular transmission during repetitive activation.NEW & NOTEWORTHY Neurotrophin brain-derived neurotrophic factor (BDNF) enhances neuromuscular transmission via activation of tropomyosin-related kinase receptor B (TrkB). Rat phrenic nerve-diaphragm muscle preparations were used to determine the rapid effect of BDNF on synaptic quantal release during repetitive stimulation. BDNF treatment significantly enhanced quantal release at all fiber types. BDNF increased synaptic vesicle cycling (measured using FM4-64 fluorescence uptake); conversely, inhibiting BDNF/TrkB signaling decreased FM4-64 uptake.
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Affiliation(s)
- Carlos B Mantilla
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Leonid G Ermilov
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Sarah M Greising
- School of Kinesiology, University of Minnesota, Minneapolis, Minnesota, United States
| | - Heather M Gransee
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Wen-Zhi Zhan
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Gary C Sieck
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
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2
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Cristobal CD, Lee HK. Development of myelinating glia: An overview. Glia 2022; 70:2237-2259. [PMID: 35785432 PMCID: PMC9561084 DOI: 10.1002/glia.24238] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 01/07/2023]
Abstract
Myelin is essential to nervous system function, playing roles in saltatory conduction and trophic support. Oligodendrocytes (OLs) and Schwann cells (SCs) form myelin in the central and peripheral nervous systems respectively and follow different developmental paths. OLs are neural stem-cell derived and follow an intrinsic developmental program resulting in a largely irreversible differentiation state. During embryonic development, OL precursor cells (OPCs) are produced in distinct waves originating from different locations in the central nervous system, with a subset developing into myelinating OLs. OPCs remain evenly distributed throughout life, providing a population of responsive, multifunctional cells with the capacity to remyelinate after injury. SCs derive from the neural crest, are highly dependent on extrinsic signals, and have plastic differentiation states. SC precursors (SCPs) are produced in early embryonic nerve structures and differentiate into multipotent immature SCs (iSCs), which initiate radial sorting and differentiate into myelinating and non-myelinating SCs. Differentiated SCs retain the capacity to radically change phenotypes in response to external signals, including becoming repair SCs, which drive peripheral regeneration. While several transcription factors and myelin components are common between OLs and SCs, their differentiation mechanisms are highly distinct, owing to their unique lineages and their respective environments. In addition, both OLs and SCs respond to neuronal activity and regulate nervous system output in reciprocal manners, possibly through different pathways. Here, we outline their basic developmental programs, mechanisms regulating their differentiation, and recent advances in the field.
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Affiliation(s)
- Carlo D. Cristobal
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA
| | - Hyun Kyoung Lee
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA,Department of PediatricsBaylor College of MedicineHoustonTexasUSA,Department of NeuroscienceBaylor College of MedicineHoustonTexasUSA
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3
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BDNF Spinal Overexpression after Spinal Cord Injury Partially Protects Soleus Neuromuscular Junction from Disintegration, Increasing VAChT and AChE Transcripts in Soleus but Not Tibialis Anterior Motoneurons. Biomedicines 2022; 10:biomedicines10112851. [DOI: 10.3390/biomedicines10112851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/20/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
After spinal cord transection (SCT) the interaction between motoneurons (MNs) and muscle is impaired, due to reorganization of the spinal network after a loss of supraspinal inputs. Rats subjected to SCT, treated with intraspinal injection of a AAV-BDNF (brain-derived neurotrophic factor) construct, partially regained the ability to walk. The central effects of this treatment have been identified, but its impact at the neuromuscular junction (NMJ) has not been characterized. Here, we compared the ability of NMJ pre- and postsynaptic machinery in the ankle extensor (Sol) and flexor (TA) muscles to respond to intraspinal AAV-BDNF after SCT. The gene expression of cholinergic molecules (VAChT, ChAT, AChE, nAChR, mAChR) was investigated in tracer-identified, microdissected MN perikarya, and in muscle fibers with the use of qPCR. In the NMJs, a distribution of VAChT, nAChR and Schwann cells was studied by immunofluorescence, and of synaptic vesicles and membrane active zones by electron microscopy. We showed partial protection of the Sol NMJs from disintegration, and upregulation of the VAChT and AChE transcripts in the Sol, but not the TA MNs after spinal enrichment with BDNF. We propose that the observed discrepancy in response to BDNF treatment is an effect of difference in the TrkB expression setting BDNF responsiveness, and of BDNF demands in Sol and TA muscles.
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4
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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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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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Ryu SH, Hong SM, Khan Z, Lee SK, Vishwanath M, Turk A, Yeon SW, Jo YH, Lee DH, Lee JK, Hwang BY, Jung JK, Kim SY, Lee MK. Neurotrophic isoindolinones from the fruiting bodies of Hericium erinaceus. Bioorg Med Chem Lett 2021; 31:127714. [DOI: 10.1016/j.bmcl.2020.127714] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/07/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022]
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7
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Petrov KA, Nikolsky EE, Masson P. Autoregulation of Acetylcholine Release and Micro-Pharmacodynamic Mechanisms at Neuromuscular Junction: Selective Acetylcholinesterase Inhibitors for Therapy of Myasthenic Syndromes. Front Pharmacol 2018; 9:766. [PMID: 30050445 PMCID: PMC6052098 DOI: 10.3389/fphar.2018.00766] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/25/2018] [Indexed: 12/22/2022] Open
Abstract
Neuromuscular junctions (NMJs) are directly involved into such indispensable to life processes as respiration and locomotion. However, motor nerve forms only one synaptic contact at each muscle fiber. This unique configuration requires specific properties and constrains to be effective. The very high density of acetylcholine receptors (AChRs) of muscle type in synaptic cleft and an excess of acetylcholine (ACh) released under physiological conditions make this synapse extremely reliable. Nevertheless, under pathological conditions such as myasthenia gravis and congenital myasthenic syndromes, the safety factor can be markedly reduced. Drugs used for short-term symptomatic therapy of these pathological states, cause partial inhibition of cholinesterases (ChEs). These enzymes catalyze the hydrolysis of ACh, thus terminate its action on AChRs. Extension of the lifetime of ACh molecules compensates muscular AChRs abnormalities and, consequently, rescues muscle contractions. In this mini review, we will first outline the functional organization of the NMJ, and then, consider the concept of the safety factor and how it may be changed. This will be followed by a look at autoregulation of ACh release that influences the safety factor of NMJs. Finally, we will consider the morphological features of NMJs as a putative reserve to increase effectiveness of pathological muscle weakness therapy by ChEs inhibitors due to opportunity to use micro-pharmacodynamic mechanisms.
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Affiliation(s)
- Konstantin A Petrov
- A.E. Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan, Russia.,Neuropharmacology Lab, Kazan Federal University, Kazan, Russia
| | - Evgeny E Nikolsky
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan, Russia
| | - Patrick Masson
- Neuropharmacology Lab, Kazan Federal University, Kazan, Russia
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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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Hurtado E, Cilleros V, Nadal L, Simó A, Obis T, Garcia N, Santafé MM, Tomàs M, Halievski K, Jordan CL, Lanuza MA, Tomàs J. Muscle Contraction Regulates BDNF/TrkB Signaling to Modulate Synaptic Function through Presynaptic cPKCα and cPKCβI. Front Mol Neurosci 2017; 10:147. [PMID: 28572757 PMCID: PMC5436293 DOI: 10.3389/fnmol.2017.00147] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/01/2017] [Indexed: 01/09/2023] Open
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) acts via tropomyosin-related kinase B receptor (TrkB) to regulate synapse maintenance and function in the neuromuscular system. The potentiation of acetylcholine (ACh) release by BDNF requires TrkB phosphorylation and Protein Kinase C (PKC) activation. BDNF is secreted in an activity-dependent manner but it is not known if pre- and/or postsynaptic activities enhance BDNF expression in vivo at the neuromuscular junction (NMJ). Here, we investigated whether nerve and muscle cell activities regulate presynaptic conventional PKC (cPKCα and βI) via BDNF/TrkB signaling to modulate synaptic strength at the NMJ. To differentiate the effects of presynaptic activity from that of muscle contraction, we stimulated the phrenic nerve of rat diaphragms (1 Hz, 30 min) with or without contraction (abolished by μ-conotoxin GIIIB). Then, we performed ELISA, Western blotting, qRT-PCR, immunofluorescence and electrophysiological techniques. We found that nerve-induced muscle contraction: (1) increases the levels of mature BDNF protein without affecting pro-BDNF protein or BDNF mRNA levels; (2) downregulates TrkB.T1 without affecting TrkB.FL or p75 neurotrophin receptor (p75) levels; (3) increases presynaptic cPKCα and cPKCβI protein level through TrkB signaling; and (4) enhances phosphorylation of cPKCα and cPKCβI. Furthermore, we demonstrate that cPKCβI, which is exclusively located in the motor nerve terminals, increases activity-induced acetylcholine release. Together, these results show that nerve-induced muscle contraction is a key regulator of BDNF/TrkB signaling pathway, retrogradely activating presynaptic cPKC isoforms (in particular cPKCβI) to modulate synaptic function. These results indicate that a decrease in neuromuscular activity, as occurs in several neuromuscular disorders, could affect the BDNF/TrkB/PKC pathway that links pre- and postsynaptic activity to maintain neuromuscular function.
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Affiliation(s)
- Erica Hurtado
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Víctor Cilleros
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Laura Nadal
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Anna Simó
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Teresa Obis
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Neus Garcia
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Manel M Santafé
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Marta Tomàs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | | | - Cynthia L Jordan
- Neuroscience Program, Michigan State UniversityMichigan, MI, United States
| | - Maria A Lanuza
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Josep Tomàs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
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10
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Takamori M. Synaptic Homeostasis and Its Immunological Disturbance in Neuromuscular Junction Disorders. Int J Mol Sci 2017; 18:ijms18040896. [PMID: 28441759 PMCID: PMC5412475 DOI: 10.3390/ijms18040896] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/04/2017] [Accepted: 04/19/2017] [Indexed: 12/14/2022] Open
Abstract
In the neuromuscular junction, postsynaptic nicotinic acetylcholine receptor (nAChR) clustering, trans-synaptic communication and synaptic stabilization are modulated by the molecular mechanisms underlying synaptic plasticity. The synaptic functions are based presynaptically on the active zone architecture, synaptic vesicle proteins, Ca2+ channels and synaptic vesicle recycling. Postsynaptically, they are based on rapsyn-anchored nAChR clusters, localized sensitivity to ACh, and synaptic stabilization via linkage to the extracellular matrix so as to be precisely opposed to the nerve terminal. Focusing on neural agrin, Wnts, muscle-specific tyrosine kinase (a mediator of agrin and Wnts signalings and regulator of trans-synaptic communication), low-density lipoprotein receptor-related protein 4 (the receptor of agrin and Wnts and participant in retrograde signaling), laminin-network (including muscle-derived agrin), extracellular matrix proteins (participating in the synaptic stabilization) and presynaptic receptors (including muscarinic and adenosine receptors), we review the functional structures of the synapse by making reference to immunological pathogenecities in postsynaptic disease, myasthenia gravis. The synapse-related proteins including cortactin, coronin-6, caveolin-3, doublecortin, R-spondin 2, amyloid precursor family proteins, glia cell-derived neurotrophic factor and neurexins are also discussed in terms of their possible contribution to efficient synaptic transmission at the neuromuscular junction.
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Affiliation(s)
- Masaharu Takamori
- Neurological Center, Kanazawa-Nishi Hospital, Kanazawa, Ishikawa 920-0025, Japan.
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11
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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: 64] [Impact Index Per Article: 7.1] [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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12
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Monk KR, Feltri ML, Taveggia C. New insights on Schwann cell development. Glia 2015; 63:1376-93. [PMID: 25921593 PMCID: PMC4470834 DOI: 10.1002/glia.22852] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/13/2015] [Indexed: 12/11/2022]
Abstract
In the peripheral nervous system, Schwann cells are glial cells that are in intimate contact with axons throughout development. Schwann cells generate the insulating myelin sheath and provide vital trophic support to the neurons that they ensheathe. Schwann cell precursors arise from neural crest progenitor cells, and a highly ordered developmental sequence controls the progression of these cells to become mature myelinating or nonmyelinating Schwann cells. Here, we discuss both seminal discoveries and recent advances in our understanding of the molecular mechanisms that drive Schwann cell development and myelination with a focus on cell-cell and cell-matrix signaling events.
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Affiliation(s)
- Kelly R Monk
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri
| | - M Laura Feltri
- Department of Biochemistry and Neurology, Hunter James Kelly Research Institute, University at Buffalo, State University of New York, Buffalo, New York
| | - Carla Taveggia
- Division of Neuroscience and INSPE, San Raffaele Scientific Institute, Milan, Italy
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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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Mitochondrial alarmins released by degenerating motor axon terminals activate perisynaptic Schwann cells. Proc Natl Acad Sci U S A 2015; 112:E497-505. [PMID: 25605902 DOI: 10.1073/pnas.1417108112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An acute and highly reproducible motor axon terminal degeneration followed by complete regeneration is induced by some animal presynaptic neurotoxins, representing an appropriate and controlled system to dissect the molecular mechanisms underlying degeneration and regeneration of peripheral nerve terminals. We have previously shown that nerve terminals exposed to spider or snake presynaptic neurotoxins degenerate as a result of calcium overload and mitochondrial failure. Here we show that toxin-treated primary neurons release signaling molecules derived from mitochondria: hydrogen peroxide, mitochondrial DNA, and cytochrome c. These molecules activate isolated primary Schwann cells, Schwann cells cocultured with neurons and at neuromuscular junction in vivo through the MAPK pathway. We propose that this inter- and intracellular signaling is involved in triggering the regeneration of peripheral nerve terminals affected by other forms of neurodegenerative diseases.
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Schwann cells sense and control acetylcholine spillover at the neuromuscular junction by α7 nicotinic receptors and butyrylcholinesterase. J Neurosci 2014; 34:11870-83. [PMID: 25186736 DOI: 10.1523/jneurosci.0329-14.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Terminal Schwann cells (TSCs) are key components of the mammalian neuromuscular junction (NMJ). How the TSCs sense the synaptic activity in physiological conditions remains unclear. We have taken advantage of the distinct localization of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at the NMJ to bring out the function of different ACh receptors (AChRs). AChE is clustered by the collagen Q in the synaptic cleft and prevents the repetitive activation of muscle nicotinic AChRs. We found that BChE is anchored at the TSC by a proline-rich membrane anchor, the small transmembrane protein anchor of brain AChE. When BChE was specifically inhibited, ACh release was significant depressed through the activation of α7 nAChRs localized on the TSC and activated by the spillover of ACh. When both AChE and BChE were inhibited, the spillover increased and induced a dramatic reduction of ACh release that compromised the muscle twitch triggered by the nerve stimulation. α7 nAChRs at the TSC may act as a sensor for spillover of ACh adjusted by BChE and may represent an extrasynaptic sensor for homeostasis at the NMJ. In myasthenic rats, selective inhibition of AChE is more effective in rescuing muscle function than the simultaneous inhibition of AChE and BChE because the concomitant inhibition of BChE counteracts the positive action of AChE inhibition. These results show that inhibition of BChE should be avoided during the treatment of myasthenia and the pharmacological reversal of residual curarization after anesthesia.
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Darabid H, Perez-Gonzalez AP, Robitaille R. Neuromuscular synaptogenesis: coordinating partners with multiple functions. Nat Rev Neurosci 2014; 15:630-1. [DOI: 10.1038/nrn3821] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Moloney EB, de Winter F, Verhaagen J. ALS as a distal axonopathy: molecular mechanisms affecting neuromuscular junction stability in the presymptomatic stages of the disease. Front Neurosci 2014; 8:252. [PMID: 25177267 PMCID: PMC4132373 DOI: 10.3389/fnins.2014.00252] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/29/2014] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is being redefined as a distal axonopathy, in that many molecular changes influencing motor neuron degeneration occur at the neuromuscular junction (NMJ) at very early stages of the disease prior to symptom onset. A huge variety of genetic and environmental causes have been associated with ALS, and interestingly, although the cause of the disease can differ, both sporadic and familial forms of ALS show a remarkable similarity in terms of disease progression and clinical manifestation. The NMJ is a highly specialized synapse, allowing for controlled signaling between muscle and nerve necessary for skeletal muscle function. In this review we will evaluate the clinical, animal experimental and cellular/molecular evidence that supports the idea of ALS as a distal axonopathy. We will discuss the early molecular mechanisms that occur at the NMJ, which alter the functional abilities of the NMJ. Specifically, we focus on the role of axon guidance molecules on the stability of the cytoskeleton and how these molecules may directly influence the cells of the NMJ in a way that may initiate or facilitate the dismantling of the neuromuscular synapse in the presymptomatic stages of ALS.
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Affiliation(s)
- Elizabeth B. Moloney
- Department of Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and ScienceAmsterdam, Netherlands
| | - Fred de Winter
- Department of Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and ScienceAmsterdam, Netherlands
- Department of Neurosurgery, Leiden University Medical CentreLeiden, Netherlands
| | - Joost Verhaagen
- Department of Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and ScienceAmsterdam, Netherlands
- Centre for Neurogenomics and Cognitive Research, Vrije Universiteit AmsterdamAmsterdam, Netherlands
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Sartini S, Bartolini F, Ambrogini P, Betti M, Ciuffoli S, Lattanzi D, Di Palma M, Cuppini R. Motor activity affects adult skeletal muscle re-innervation acting via tyrosine kinase receptors. Eur J Neurosci 2013; 37:1394-403. [PMID: 23373744 DOI: 10.1111/ejn.12130] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 02/01/2023]
Abstract
Recently, muscle expression of brain-derived neurotrophic factor (BDNF) mRNA and protein under activity control has been reported. BDNF is a neurotrophin known to be involved in axon sprouting in the CNS. Hence, we set out to study the effect of chronic treadmill mid-intensity running on adult rat muscle re-innervation, and to explore the involvement of BDNF and tropomyosin-related kinase (Trk) receptors. After nerve crush, muscle re-innervation was evaluated using intracellular recordings, tension recordings, immunostaining and Western blot analyses. An enhanced muscle multiple innervation was found in running rats that was fully reversed to control values blocking Trk receptors or interrupting the running activity. An increase in muscle multiple innervation was also found in sedentary rats treated with a selective TrkB receptor agonist. The expression of TrkB receptors by intramuscular axons was demonstrated, and increased muscle expression of BDNF was found in running animals. The increase in muscle multiple innervation was consistent with the faster muscle re-innervation that we found in running animals. We conclude that, when regenerating axons contact muscle cells, muscle activity progressively increases modulating BDNF and possibly other growth factors, which in turn, acting via Trk receptors, induce axon sprouting to re-innervate skeletal muscle.
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Affiliation(s)
- Stefano Sartini
- Department of Earth, Life and Environmental Sciences, Section of Physiology, Campus Scientifico Enrico Mattei, via Ca' le Suore 2, I-61029 Urbino, Italy.
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Batista-de-Oliveira M, Monte-Silva-Machado K, Paiva A, Lima H, Fregni F, Guedes R. Favorable and unfavorable lactation modulates the effects of electrical stimulation on brain excitability: A spreading depression study in adult rats. Life Sci 2012; 91:306-11. [DOI: 10.1016/j.lfs.2012.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 06/06/2012] [Accepted: 07/06/2012] [Indexed: 11/24/2022]
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Tian X, Wang S, Zhang Z, Lv D. Rat bone marrow-derived Schwann-like cells differentiated by the optimal inducers combination on microfluidic chip and their functional performance. PLoS One 2012; 7:e42804. [PMID: 22880114 PMCID: PMC3411850 DOI: 10.1371/journal.pone.0042804] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 07/11/2012] [Indexed: 11/29/2022] Open
Abstract
Numerous researches demonstrated the possibility of derivation of Schwann-like (SC-like) cells in vitro from bone marrow stromal cells (BMSCs). However, the concentration of the induce factors were different in those studies, especially for the critical factors forskolin (FSK) and β-heregulin (HRG). Here, we used a new and useful method to build an integrated microfluidic chip for rapid analyses of the optimal combination between the induce factors FSK and HRG. The microfluidic device was mainly composed of an upstream concentration gradient generator (CGG) and a downstream cell culture module. Rat BMSCs were cultured in the cell chambers for 11 days at the different concentrations of induce factors generated by CGG. The result of immunofluorescence staining on-chip showed that the group of 4.00 µM FSK and 250.00 ng/ml HRG presented an optimal effect to promote the derivation of SC-like cells. Moreover, the optimal SC-like cells obtained on-chip were further tested using DRG co-culture and ELISA to detect their functional performance. Our findings demonstrate that SC-like cells could be obtained with high efficiency and functional performance in the optimal inducers combination.
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Affiliation(s)
| | - Shouyu Wang
- Department of Orthopedics, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, People's Republic of China
- * E-mail: (DCL); (SYW)
| | | | - Decheng Lv
- Department of Orthopedics, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, People's Republic of China
- * E-mail: (DCL); (SYW)
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Brink DL, Gilbert M, Xie X, Petley-Ragan L, Auld VJ. Glial processes at the Drosophila larval neuromuscular junction match synaptic growth. PLoS One 2012; 7:e37876. [PMID: 22666403 PMCID: PMC3362601 DOI: 10.1371/journal.pone.0037876] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 04/25/2012] [Indexed: 11/19/2022] Open
Abstract
Glia are integral participants in synaptic physiology, remodeling and maturation from blowflies to humans, yet how glial structure is coordinated with synaptic growth is unknown. To investigate the dynamics of glial development at the Drosophila larval neuromuscular junction (NMJ), we developed a live imaging system to establish the relationship between glia, neuronal boutons, and the muscle subsynaptic reticulum. Using this system we observed processes from two classes of peripheral glia present at the NMJ. Processes from the subperineurial glia formed a blood-nerve barrier around the axon proximal to the first bouton. Processes from the perineurial glial extended beyond the end of the blood-nerve barrier into the NMJ where they contacted synapses and extended across non-synaptic muscle. Growth of the glial processes was coordinated with NMJ growth and synaptic activity. Increasing synaptic size through elevated temperature or the highwire mutation increased the extent of glial processes at the NMJ and conversely blocking synaptic activity and size decreased the presence and size of glial processes. We found that elevated temperature was required during embryogenesis in order to increase glial expansion at the nmj. Therefore, in our live imaging system, glial processes at the NMJ are likely indirectly regulated by synaptic changes to ensure the coordinated growth of all components of the tripartite larval NMJ.
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Affiliation(s)
- Deidre L. Brink
- Department of Zoology, Cell and Developmental Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mary Gilbert
- Department of Zoology, Cell and Developmental Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Xiaojun Xie
- Department of Zoology, Cell and Developmental Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lindsay Petley-Ragan
- Department of Zoology, Cell and Developmental Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vanessa J. Auld
- Department of Zoology, Cell and Developmental Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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22
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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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Involvement of spinal neurotrophin-3 in electroacupuncture analgesia and inhibition of spinal glial activation in rat model of monoarthritis. THE JOURNAL OF PAIN 2011; 12:974-84. [PMID: 21680256 DOI: 10.1016/j.jpain.2011.03.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/10/2011] [Accepted: 03/08/2011] [Indexed: 11/23/2022]
Abstract
UNLABELLED Although electroacupuncture (EA) has been proven to effectively relieve pain associated with arthritis, the underlying mechanism of EA analgesia requires further investigation. Here, the involvement of spinal neurotrophin-3 (NT-3) in EA's analgesic effects on complete Freund's adjuvant (CFA)-induced inflammatory pain was examined. The present study demonstrated that: 1) repeated EA stimulation of ipsilateral GB30 and GB34 acupoints remarkably suppressed CFA-induced hyperalgesia; 2) EA treatment markedly enhanced the upregulation of spinal NT-3 mRNA and protein levels following CFA injection; 3) antisense oligodeoxynucleotides (ODN) specifically against NT-3 intrathecally administered during EA treatment for 7 days significantly attenuated the EA analgesia; and 4) the suppressed expression of spinal GFAP (astrocytic marker), OX-42 (microglial marker) as well as proinflammatory cytokines, interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α by EA treatment was significantly attenuated following NT-3 antisense ODN delivery. These results suggested that endogenous NT-3 may be involved in the analgesic effect of EA on inflammatory pain in rats, mediated through the inhibition of spinal glial activity as well as proinflammatory cytokine production. PERSPECTIVE The present study may initiate a discussion on the possible roles of NT-3/glia/cytokines in the therapeutic effects of acupuncture and provide insight on the mechanism underlie the analgesic effects of acupuncture on pain associated with arthritis.
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Rana OR, Saygili E, Gemein C, Zink MD, Buhr A, Saygili E, Mischke K, Nolte KW, Weis J, Weber C, Marx N, Schauerte P. Chronic Electrical Neuronal Stimulation Increases Cardiac Parasympathetic Tone by Eliciting Neurotrophic Effects. Circ Res 2011; 108:1209-19. [DOI: 10.1161/circresaha.110.234518] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Rationale:
Recently, we provided a technique of chronic high-frequency electric stimulation (HFES) of the right inferior ganglionated plexus for ventricular rate control during atrial fibrillation in dogs and humans. In these experiments, we observed a decrease of the intrinsic ventricular rate during the first 4 to 5 months when HFES was intermittently shut off.
Objective:
We thus hypothesized that HFES might elicit trophic effects on cardiac neurons, which in turn increase baseline parasympathetic tone of the atrioventricular node.
Methods and Results:
In mongrel dogs atrial fibrillation was induced by rapid atrial pacing. Endocardial HFES of the right inferior ganglionated plexus, which contains abundant fibers to the atrioventricular node, was performed for 2 years. Sham-operated nonstimulated dogs served as control. In chronic neurostimulated dogs, we found an increased neuronal cell size accompanied by an increase of choline acetyltransferase and unchanged tyrosine hydroxylase protein expression as compared with unstimulated dogs. Moreover, β-nerve growth factor (NGF) and neurotrophin (NT)-3 were upregulated in chronically neurostimulated dogs. In vitro, HFES of cultured neurons of interatrial ganglionated plexus from adult rats increased neuronal growth accompanied by upregulation of NGF, NT-3, glial-derived neurotrophic factor (GDNF), ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) expression. NGF was identified as the main growth-inducing factor, whereas NT-3 did not affect HFES-induced growth. However, NT-3 could be identified as an important acetylcholine-upregulating factor.
Conclusions:
HFES of cardiac neurons in vivo and in vitro causes neuronal cellular hypertrophy, which is mediated by NGF and boosters cellular function by NT-3–mediated acetylcholine upregulation. This knowledge may contribute to develop HFES techniques to augment cardiac parasympathetic tone.
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Affiliation(s)
- Obaida R. Rana
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Erol Saygili
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Christopher Gemein
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Matthias D.H. Zink
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Alexandra Buhr
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Esra Saygili
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Karl Mischke
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Kay W. Nolte
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Joachim Weis
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Christian Weber
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Nikolaus Marx
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
| | - Patrick Schauerte
- From the Department of Cardiology (O.R.R., Erol Saygili, C.G., M.D.H.Z., A.B., Esra Saygili, K.M., N.M., P.S.) and Institutes for Neuropathology (K.W.N., J.W.) and Molecular Cardiovascular Research (C.W.), RWTH Aachen University, Germany
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Paban V, Chambon C, Manrique C, Touzet C, Alescio-Lautier B. Neurotrophic signaling molecules associated with cholinergic damage in young and aged rats: Environmental enrichment as potential therapeutic agent. Neurobiol Aging 2011; 32:470-85. [DOI: 10.1016/j.neurobiolaging.2009.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/16/2009] [Accepted: 03/18/2009] [Indexed: 10/20/2022]
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Age affects reciprocal cellular interactions in neuromuscular synapses following peripheral nerve injury. Ageing Res Rev 2011; 10:43-53. [PMID: 20943206 DOI: 10.1016/j.arr.2010.10.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/04/2010] [Accepted: 10/04/2010] [Indexed: 01/09/2023]
Abstract
Studies of the influence of age on regeneration and reinnervation in the peripheral nervous system (PNS) and neuromuscular junction (NMJ) are reviewed, with a particular focus on aged and denervated skeletal muscles. The morphological and functional features of incomplete regeneration and reinnervation are compared between adult and aged animals. In addition, some possible mechanisms of the age-related defects will be discussed. Increased fragmentation or damage in individual components of the NMJ (terminal Schwann cells (TSCs), axon terminals and acetylcholine receptor sites occurs during muscle reinnervation following PNS injury in the aged animals. The capacity to produce ultraterminal sprouting or multiple innervation secondary to PNS injury is maintained, but not the capacity to eliminate such anomalous axonal profiles. The frequency and accuracy of reoccupation of the synaptic sites by TSCs and axon terminals are impaired. Thus, despite the capability of extending neural processes, the rate at which regenerating nerve fibers grow, mature and precisely appose the postsynaptic muscle fiber is impaired, resulting in the failure of re-establishment of the normal single motor innervation in the NMJ. A complex set of cellular interactions in the NMJ are known to participate in the neurotrophism and neurotrophism to support growth of the regenerating and sprouting axons and their pathfinding to direct the target muscle fiber. Besides the capability of α-motoneurons, signaling originating from the TSCs and muscle may be impaired during aging.
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Garcia N, Santafe MM, Tomàs M, Lanuza MA, Besalduch N, Tomàs J. Involvement of brain-derived neurotrophic factor (BDNF) in the functional elimination of synaptic contacts at polyinnervated neuromuscular synapses during development. J Neurosci Res 2010; 88:1406-19. [PMID: 20029969 DOI: 10.1002/jnr.22320] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We use immunohistochemistry to describe the localization of brain-derived neurotrophic factor (BDNF) and its receptors trkB and p75(NTR) in the neuromuscular synapses of postnatal rats (P6-P7) during the synapse elimination period. The receptor protein p75(NTR) is present in the nerve terminal, muscle cell and glial Schwann cell whereas BDNF and trkB proteins can be detected mainly in the pre- and postsynaptic elements. Exogenously applied BDNF (10 nM for 3 hr or 50 nM for 1 hr) increases ACh release from singly and dually innervated synapses. This effect may be specific for BDNF because the neurotrophin NT-4 (2-8 nM) does not modulate release at P6-P7. Blocking the receptors trkB and p75(NTR) (with K-252a and anti-p75-192-IgG, respectively) completely abolishes the potentiating effect of exogenous BDNF. In addition, exogenous BDNF transiently recruits functionally depressed silent terminals, and this effect seems to be mediated by trkB. Calcium ions, the L-type voltage-dependent calcium channels and protein kinase C are involved in BDNF-mediated nerve ending recruitment. Blocking experiments suggest that endogenous BDNF could operate through p75(NTR) receptors coupled to potentiate ACh release in all nerve terminals because the anti-p75-192-IgG reduces release. However, blocking the trkB receptor (K-252a) or neutralizing endogenous BDNF with the trkB-IgG fusion protein reveals a trkB-mediated release inhibition on almost mature strong endings in dual junctions. Taken together these results suggest that a BDNF-induced p75(NTR)-mediated ACh release potentiating mechanism and a BDNF-induced trkB-mediated release inhibitory mechanism may contribute to developmental synapse disconnection.
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Affiliation(s)
- N Garcia
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer Sant Llorenç, Spain
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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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Bélair EL, Vallée J, Robitaille R. In vivo long-term synaptic plasticity of glial cells. J Physiol 2010; 588:1039-56. [PMID: 20142269 DOI: 10.1113/jphysiol.2009.178988] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Evidence showing the ability of glial cells to detect, respond to and modulate synaptic transmission and plasticity has contributed to the notion of glial cells as active synaptic partners. However, synaptically induced plasticity of glia themselves remains ill defined. Here we used the amphibian neuromuscular junction (NMJ) to study plasticity of perisynaptic Schwann cells (PSCs), glial cells at this synapse, following long-term in vivo modifications of synaptic activity. We used two models that altered synaptic activity in different manners. First, chronic blockade of postsynaptic nicotinic receptors using alpha-bungarotoxin (alpha-BTx) decreased facilitation, increased synaptic depression and decreased post-tetanic potentiation (PTP). Second, chronic nerve stimulation increased facilitation and resistance to synaptic depression, while leaving PTP unaltered. Our results indicate that there is no direct relationship between transmitter release and PSC calcium responses. Indeed, despite changes in transmitter release and plasticity in stimulated NMJs, nerve-evoked PSC calcium responses were similar to control. Similarly, PSC calcium responses in alpha-BTx treated NMJs were delayed and smaller in amplitude, even though basal level of transmitter release was increased. Also, when isolating purinergic and muscarinic components of PSC calcium responses, we found an increased sensitivity to ATP and a decreased sensitivity to muscarine in chronically stimulated NMJs. Conversely, in alpha-BTx treated NMJs, PSC sensitivity remained unaffected, but ATP- and muscarine-induced calcium responses were prolonged. Thus, our results reveal complex modifications of PSC properties, with differential modulation of signalling pathways that might underlie receptor regulation or changes in Ca(2+) handling. Importantly, similar to neurons, perisynaptic glial cells undergo plastic changes induced by altered synaptic activity.
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Affiliation(s)
- Eve-Lyne Bélair
- Département de physiologie, Faculté de médecine, Université de Montréal, PO box 6128 Succursale Centre-ville, Montréal, Québec, Canada
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Distinct muscarinic acetylcholine receptor subtypes contribute to stability and growth, but not compensatory plasticity, of neuromuscular synapses. J Neurosci 2010; 29:14942-55. [PMID: 19940190 DOI: 10.1523/jneurosci.2276-09.2009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Muscarinic acetylcholine receptors (mAChRs) modulate synaptic function, but whether they influence synaptic structure remains unknown. At neuromuscular junctions (NMJs), mAChRs have been implicated in compensatory sprouting of axon terminals in paralyzed or denervated muscles. Here we used pharmacological and genetic inhibition and localization studies of mAChR subtypes at mouse NMJs to demonstrate their roles in synaptic stability and growth but not in compensatory sprouting. M(2) mAChRs were present solely in motor neurons, whereas M(1), M(3), and M(5) mAChRs were associated with Schwann cells and/or muscle fibers. Blockade of all five mAChR subtypes with atropine evoked pronounced effects, including terminal sprouting, terminal withdrawal, and muscle fiber atrophy. In contrast, methoctramine, an M(2/4)-preferring antagonist, induced terminal sprouting and terminal withdrawal, but no muscle fiber atrophy. Consistent with this observation, M(2)(-/-) but no other mAChR mutant mice exhibited spontaneous sprouting accompanied by extensive loss of parental terminal arbors. Terminal sprouting, however, seemed not to be the causative defect because partial loss of terminal branches was common even in the M(2)(-/-) NMJs without sprouting. Moreover, compensatory sprouting after paralysis or partial denervation was normal in mice deficient in M(2) or other mAChR subtypes. We also found that many NMJs of M(5)(-/-) mice were exceptionally small and reduced in proportion to the size of parental muscle fibers. These findings show that axon terminals are unstable without M(2) and that muscle fiber growth is defective without M(5). Subtype-specific muscarinic signaling provides a novel means for coordinating activity-dependent development and maintenance of the tripartite synapse.
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Abstract
The CNS contains relatively few unmyelinated nerve fibers, and thus benefits from the advantages that are conferred by myelination, including faster conduction velocities, lower energy consumption for impulse transmission, and greater stability of point-to-point connectivity. In the PNS many fibers or regions of fibers the Schwann do not form myelin. Examples include C fibers nociceptors, postganglionic sympathetic fibers, and the Schwann cells associated with motor nerve terminals at neuromuscular junctions. These examples retain a degree of plasticity and a capacity to sprout collaterally that is unusual in myelinated fibers. Nonmyelin-forming Schwann cells, including those associated with uninjured fibers, have the capacity to act as the "first responders" to injury or disease in their neighborhoods.
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Affiliation(s)
- John W Griffin
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Schwann cell mediated trophic effects by differentiated mesenchymal stem cells. Exp Cell Res 2008; 314:2692-701. [DOI: 10.1016/j.yexcr.2008.05.013] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 05/22/2008] [Accepted: 05/22/2008] [Indexed: 01/01/2023]
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Theodosis DT, Poulain DA, Oliet SHR. Activity-Dependent Structural and Functional Plasticity of Astrocyte-Neuron Interactions. Physiol Rev 2008; 88:983-1008. [DOI: 10.1152/physrev.00036.2007] [Citation(s) in RCA: 387] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Observations from different brain areas have established that the adult nervous system can undergo significant experience-related structural changes throughout life. Less familiar is the notion that morphological plasticity affects not only neurons but glial cells as well. Yet there is abundant evidence showing that astrocytes, the most numerous cells in the mammalian brain, are highly mobile. Under physiological conditions as different as reproduction, sensory stimulation, and learning, they display a remarkable structural plasticity, particularly conspicuous at the level of their lamellate distal processes that normally ensheath all portions of neurons. Distal astrocytic processes can undergo morphological changes in a matter of minutes, a remodeling that modifies the geometry and diffusion properties of the extracellular space and relationships with adjacent neuronal elements, especially synapses. Astrocytes respond to neuronal activity via ion channels, neurotransmitter receptors, and transporters on their processes; they transmit information via release of neuroactive substances. Where astrocytic processes are mobile then, astrocytic-neuronal interactions become highly dynamic, a plasticity that has important functional consequences since it modifies extracellular ionic homeostasis, neurotransmission, gliotransmission, and ultimately neuronal function at the cellular and system levels. Although a complete picture of intervening cellular mechanisms is lacking, some have been identified, notably certain permissive molecular factors common to systems capable of remodeling (cell surface and extracellular matrix adhesion molecules, cytoskeletal proteins) and molecules that appear specific to each system (neuropeptides, neurotransmitters, steroids, growth factors) that trigger or reverse the morphological changes.
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Feng Z, Ko CP. The Role of Glial Cells in the Formation and Maintenance of the Neuromuscular Junction. Ann N Y Acad Sci 2008; 1132:19-28. [DOI: 10.1196/annals.1405.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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