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Leung MR, Zeev-Ben-Mordehai T. Cryo-electron microscopy of cholinesterases, present and future. J Neurochem 2020; 158:1236-1243. [PMID: 33222205 PMCID: PMC8518539 DOI: 10.1111/jnc.15245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/30/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023]
Abstract
Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) exist in a variety of oligomeric forms, each with defined cellular and subcellular distributions. Although crystal structures of AChE and BChE have been available for many years, structures of the physiologically relevant ChE tetramer were only recently solved by cryo‐electron microscopy (cryo‐EM) single‐particle analysis. Here, we briefly review how these structures contribute to our understanding of cholinesterase oligomerization, highlighting the advantages of using cryo‐EM to resolve structures of protein assemblies that cannot be expressed recombinantly. We argue that the next frontier in cholinesterase structural biology is to image membrane‐anchored ChE oligomers directly in their native environment—the cell.
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Affiliation(s)
- Miguel Ricardo Leung
- Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.,The Division of Structural Biology, Wellcome Centre for Human Genetics, The University of Oxford, Oxford, UK
| | - Tzviya Zeev-Ben-Mordehai
- Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.,The Division of Structural Biology, Wellcome Centre for Human Genetics, The University of Oxford, Oxford, UK
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2
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Kaufman T, Kaplan B, Perry L, Shandalov Y, Landau S, Srugo I, Ad-El D, Levenberg S. Innervation of an engineered muscle graft for reconstruction of muscle defects. Am J Transplant 2019; 19:37-47. [PMID: 29856531 DOI: 10.1111/ajt.14957] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 01/25/2023]
Abstract
Autologous muscle flaps are commonly used to reconstruct defects that involve muscle impairment. To maintain viability and functionality of these flaps, they must be properly vascularized and innervated. Tissue-engineered muscles could potentially replace autologous muscle tissue, but still require establishment of sufficient innervation to ensure functionality. In this study, we explored the possibility of innervating engineered muscle grafts transplanted to an abdominal wall defect in mice, by transferring the native femoral nerve to the graft. Six weeks posttransplantation, nerve conduction studies and electromyography demonstrated increased innervation in engineered grafts neurotized with the femoral nerve, as compared to non-neurotized grafts. Histologic assessments revealed axonal penetration and formation of neuromuscular junctions within the grafts. The innervation process described here may advance the fabrication of a fully functional engineered muscle graft that will be of utility in clinical settings.
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Affiliation(s)
- Tal Kaufman
- Department of Plastic Surgery, Rabin Medical Center, Petach Tikva, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ben Kaplan
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel.,Bruce Rapaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Luba Perry
- Bruce Rapaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel.,Inter-departmental Program in Biotechnology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Yulia Shandalov
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Shira Landau
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | | | - Dean Ad-El
- Department of Plastic Surgery, Rabin Medical Center, Petach Tikva, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shulamit Levenberg
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel
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3
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Blotnick-Rubin E, Anglister L. Fine Localization of Acetylcholinesterase in the Synaptic Cleft of the Vertebrate Neuromuscular Junction. Front Mol Neurosci 2018; 11:123. [PMID: 29725289 PMCID: PMC5917012 DOI: 10.3389/fnmol.2018.00123] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 03/29/2018] [Indexed: 11/13/2022] Open
Abstract
Acetylcholinesterase (AChE) is concentrated at cholinergic synapses, where it is a major factor in controlling the duration of transmitter action. The concentration and localization of AChE within the synaptic cleft are in keeping with the functional requirements of the particular type of synapse. The densities of synaptic AChE at various neuromuscular junctions (NMJs) had been evaluated by quantitative EM-autoradiography using radiolabeled probes. Yet, fundamental issues concerning the precise distribution and location of the enzyme in the cleft remained open: whether and to what extent synaptic AChE is associated with pre- or postsynaptic membranes, or with synaptic basal lamina (BL), and whether it occurs only in the primary cleft (PC) or also in postjunctional folds (PJFs). Nanogold-conjugates of fasciculin, an anticholinesterase polypeptide toxin, were prepared and used to label AChE at NMJs of mouse and frog muscles. Selective intense labeling was obtained at the NMJs, with gold-labeled AChE sites distributed over the BL in the PC and the PJFs. Quantitative analysis demonstrated that AChE sites are almost exclusively located on the BL rather than on pre- or postsynaptic membranes and are distributed in the PC and down the PJFs, with a defined pattern. This localization pattern of AChE is suggested to ensure full hydrolysis of acetylcholine (ACh) bouncing off receptors, thus eliminating its unnecessary detrimental reattachment.
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Affiliation(s)
- Edna Blotnick-Rubin
- Department of Medical Neurobiology, Institute for Medical Research-Israel-Canada (IMRIC), Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Lili Anglister
- Department of Medical Neurobiology, Institute for Medical Research-Israel-Canada (IMRIC), Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Thurner M, Asim F, Garczarczyk-Asim D, Janke K, Deutsch M, Margreiter E, Troppmair J, Marksteiner R. Development of an in vitro potency assay for human skeletal muscle derived cells. PLoS One 2018; 13:e0194561. [PMID: 29566057 PMCID: PMC5864011 DOI: 10.1371/journal.pone.0194561] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 03/04/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Potency is a quantitative measure of the desired biological function of an advanced therapy medicinal product (ATMP) and is a prerequisite for market approval application (MAA). To assess the potency of human skeletal muscle-derived cells (SMDCs), which are currently investigated in clinical trials for the regeneration of skeletal muscle defects, we evaluated acetylcholinesterase (AChE), which is expressed in skeletal muscle and nervous tissue of all mammals. METHODS CD56+ SMDCs were separated from CD56- SMDCs by magnetic activated cell sorting (MACS) and both differentiated in skeletal muscle differentiation medium. AChE activity of in vitro differentiated SMDCs was correlated with CD56 expression, fusion index, cell number, cell doubling numbers, differentiation markers and compared to the clinical efficacy in patients treated with SMDCs against fecal incontinence. RESULTS CD56- SMDCs did not form multinucleated myotubes and remained low in AChE activity during differentiation. CD56+ SMDCs generated myotubes and increased in AChE activity during differentiation. AChE activity was found to accurately reflect the number of CD56+ SMDCs in culture, their fusion competence, and cell doubling number. In patients with fecal incontinence responding to SMDCs treatment, the improvement of clinical symptoms was positively linked with the AChE activity of the SMDCs injected. DISCUSSION AChE activity was found to truly reflect the in vitro differentiation status of SMDCs and to be superior to the mere use of surface markers as it reflects not only the number of myogenic SMDCs in culture but also their fusion competence and population doubling number, thus combining cell quality and quantification of the expected mode of action (MoA) of SMDCs. Moreover, the successful in vitro validation of the assay proves its suitability for routine use. Most convincingly, our results demonstrate a link between clinical efficacy and the AChE activity of the SMDCs preparations used for the treatment of fecal incontinence. Thus, we recommend using AChE activity of in vitro differentiated SMDCs as a potency measure in end stage (phase III) clinical trials using SMDCs for skeletal muscle regeneration and subsequent market approval application (MAA).
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Affiliation(s)
- Marco Thurner
- Innovacell Biotechnologie AG, Science Park, Innsbruck, Austria
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant, and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria
- * E-mail: ,
| | - Faheem Asim
- Innovacell Biotechnologie AG, Science Park, Innsbruck, Austria
| | | | - Katrin Janke
- Innovacell Biotechnologie AG, Science Park, Innsbruck, Austria
| | - Martin Deutsch
- Innovacell Biotechnologie AG, Science Park, Innsbruck, Austria
| | - Eva Margreiter
- Innovacell Biotechnologie AG, Science Park, Innsbruck, Austria
| | - Jakob Troppmair
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant, and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria
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Mis K, Grubic Z, Lorenzon P, Sciancalepore M, Mars T, Pirkmajer S. In Vitro Innervation as an Experimental Model to Study the Expression and Functions of Acetylcholinesterase and Agrin in Human Skeletal Muscle. Molecules 2017; 22:molecules22091418. [PMID: 28846617 PMCID: PMC6151842 DOI: 10.3390/molecules22091418] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/18/2017] [Accepted: 08/23/2017] [Indexed: 12/19/2022] Open
Abstract
Acetylcholinesterase (AChE) and agrin, a heparan-sulfate proteoglycan, reside in the basal lamina of the neuromuscular junction (NMJ) and play key roles in cholinergic transmission and synaptogenesis. Unlike most NMJ components, AChE and agrin are expressed in skeletal muscle and α-motor neurons. AChE and agrin are also expressed in various other types of cells, where they have important alternative functions that are not related to their classical roles in NMJ. In this review, we first focus on co-cultures of embryonic rat spinal cord explants with human skeletal muscle cells as an experimental model to study functional innervation in vitro. We describe how this heterologous rat-human model, which enables experimentation on highly developed contracting human myotubes, offers unique opportunities for AChE and agrin research. We then highlight innovative approaches that were used to address salient questions regarding expression and alternative functions of AChE and agrin in developing human skeletal muscle. Results obtained in co-cultures are compared with those obtained in other models in the context of general advances in the field of AChE and agrin neurobiology.
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Affiliation(s)
- Katarina Mis
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
| | - Zoran Grubic
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
| | - Paola Lorenzon
- Department of Life Sciences, University of Trieste, via A. Fleming 22, I-34127 Trieste, Italy.
| | - Marina Sciancalepore
- Department of Life Sciences, University of Trieste, via A. Fleming 22, I-34127 Trieste, Italy.
| | - Tomaz Mars
- Department of Life Sciences, University of Trieste, via A. Fleming 22, I-34127 Trieste, Italy.
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
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Smith AS, Passey SL, Martin NR, Player DJ, Mudera V, Greensmith L, Lewis MP. Creating Interactions between Tissue-Engineered Skeletal Muscle and the Peripheral Nervous System. Cells Tissues Organs 2016; 202:143-158. [PMID: 27825148 PMCID: PMC5175300 DOI: 10.1159/000443634] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2015] [Indexed: 12/22/2022] Open
Abstract
Effective models of mammalian tissues must allow and encourage physiologically (mimetic) correct interactions between co-cultured cell types in order to produce culture microenvironments as similar as possible to those that would normally occur in vivo. In the case of skeletal muscle, the development of such a culture model, integrating multiple relevant cell types within a biomimetic scaffold, would be of significant benefit for investigations into the development, functional performance, and pathophysiology of skeletal muscle tissue. Although some work has been published regarding the behaviour of in vitro muscle models co-cultured with organotypic slices of CNS tissue or with stem cell-derived neurospheres, little investigation has so far been made regarding the potential to maintain isolated motor neurons within a 3D biomimetic skeletal muscle culture platform. Here, we review the current state of the art for engineering neuromuscular contacts in vitro and provide original data detailing the development of a 3D collagen-based model for the co-culture of primary muscle cells and motor neurons. The devised culture system promotes increased myoblast differentiation, forming arrays of parallel, aligned myotubes on which areas of nerve-muscle contact can be detected by immunostaining for pre- and post-synaptic proteins. Quantitative RT-PCR results indicate that motor neuron presence has a positive effect on myotube maturation, suggesting neural incorporation influences muscle development and maturation in vitro. The importance of this work is discussed in relation to other published neuromuscular co-culture platforms along with possible future directions for the field.
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Affiliation(s)
- Alec S.T. Smith
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, National Centre for Sport and Exercise Medicine (NCSEM) England, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- Department of Bioengineering, University of Washington, Seattle, Wash., USA
| | - Samantha L. Passey
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, National Centre for Sport and Exercise Medicine (NCSEM) England, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, Vic., Australia
| | - Neil R.W. Martin
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, National Centre for Sport and Exercise Medicine (NCSEM) England, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Darren J. Player
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, National Centre for Sport and Exercise Medicine (NCSEM) England, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Vivek Mudera
- Division of Surgery and Interventional Science, UCL Institute of Orthopaedics and Musculoskeletal Science, London, UK
| | - Linda Greensmith
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Mark P. Lewis
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, National Centre for Sport and Exercise Medicine (NCSEM) England, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- *Prof. Mark P. Lewis, School of Sport, Exercise and Health Sciences, Loughborough University, Ashby Road, Loughborough LE11 3TU (UK), E-Mail
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7
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Mis K, Matkovic U, Pirkmajer S, Sciancalepore M, Lorenzon P, Mars T, Grubic Z. Acetylcholinesterase and agrin: different functions, similar expression patterns, multiple roles. Chem Biol Interact 2012; 203:297-301. [PMID: 23117006 DOI: 10.1016/j.cbi.2012.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/16/2012] [Accepted: 10/17/2012] [Indexed: 12/31/2022]
Abstract
Acetylcholinesterase (AChE) and agrin play unique functional roles in the neuromuscular junction (NMJ). AChE is a cholinergic and agrin a synaptogenetic component. In spite of their different functions, they share several common features: their targeting is determined by alternative splicing; unlike most other NMJ components they are expressed in both, muscle and motor neuron and both reside on the synaptic basal lamina of the NMJ. Also, both were reported to play various nonjunctional roles. However, while the origin of basal lamina bound agrin is undoubtedly neural, the neural origin of AChE, which is anchored to the basal lamina with collagenic tail ColQ, is elusive. Hypothesizing that motor neuron proteins targeted to the NMJ basal lamina share common temporal pattern of expression, which is coordinated with the formation of basal lamina, we compared expression of agrin isoforms with the expression of AChE-T and ColQ in the developing rat spinal cord at the stages before and after the formation of NMJ basal lamina. Cellular origin of AChE-T and agrin was determined by in situ hybridization and their quantitative levels by RT PCR. We found parallel increase in expression of the synaptogenetic (agrin 8) isoform of agrin and ColQ after the formation of basal lamina supporting the view that ColQ bound AChE and agrin 8 isoform are destined to the basal lamina. Catalytic AChE-T subunit and agrin isoforms 19 and 0 followed different expression patterns. In accordance with the reports of other authors, our investigations also revealed various alternative functions for AChE and agrin. We have already demonstrated participation of AChE in myoblast apoptosis; here we present the evidence that agrin promotes the maturation of heavy myosin chains and the excitation-contraction coupling. These results show that common features of AChE and agrin extend to their capacity to play multiple roles in muscle development.
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Affiliation(s)
- Katarina Mis
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Camp S, De Jaco A, Zhang L, Marquez M, De La Torre B, Taylor P. Acetylcholinesterase expression in muscle is specifically controlled by a promoter-selective enhancesome in the first intron. J Neurosci 2008; 28:2459-70. [PMID: 18322091 PMCID: PMC2692871 DOI: 10.1523/jneurosci.4600-07.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 01/09/2008] [Accepted: 01/17/2008] [Indexed: 11/21/2022] Open
Abstract
Mammalian acetylcholinesterase (AChE) gene expression is exquisitely regulated in target tissues and cells during differentiation. An intron located between the first and second exons governs a approximately 100-fold increase in AChE expression during myoblast to myotube differentiation in C2C12 cells. Regulation is confined to 255 bp of evolutionarily conserved sequence containing functional transcription factor consensus motifs that indirectly interact with the endogenous promoter. To examine control in vivo, this region was deleted by homologous recombination. The knock-out mouse is virtually devoid of AChE activity and its encoding mRNA in skeletal muscle, yet activities in brain and spinal cord innervating skeletal muscle are unaltered. The transcription factors MyoD and myocyte enhancer factor-2 appear to be responsible for muscle regulation. Selective control of AChE expression by this region is also found in hematopoietic lineages. Expression patterns in muscle and CNS neurons establish that virtually all AChE activity at the mammalian neuromuscular junction arises from skeletal muscle rather than from biosynthesis in the motoneuron cell body and axoplasmic transport.
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Affiliation(s)
- Shelley Camp
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Antonella De Jaco
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Limin Zhang
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Michael Marquez
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Brian De La Torre
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
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Bandi E, Jevšek M, Mars T, Jurdana M, Formaggio E, Sciancalepore M, Fumagalli G, Grubič Z, Ruzzier F, Lorenzon P. Neural agrin controls maturation of the excitation-contraction coupling mechanism in human myotubes developing in vitro. Am J Physiol Cell Physiol 2008; 294:C66-73. [DOI: 10.1152/ajpcell.00248.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to elucidate the mechanisms responsible for the effects of innervation on the maturation of excitation-contraction coupling apparatus in human skeletal muscle. For this purpose, we compared the establishment of the excitation-contraction coupling mechanism in myotubes differentiated in four different experimental paradigms: 1) aneurally cultured, 2) cocultured with fetal rat spinal cord explants, 3) aneurally cultured in medium conditioned by cocultures, and 4) aneurally cultured in medium supplemented with purified recombinant chick neural agrin. Ca2+ imaging indicated that coculturing human muscle cells with rat spinal cord explants increased the fraction of cells showing a functional excitation-contraction coupling mechanism. The effect of spinal cord explants was mimicked by treatment with medium conditioned by cocultures or by addition of 1 nM of recombinant neural agrin to the medium. The treatment with neural agrin increased the number of human muscle cells in which functional ryanodine receptors (RyRs) and dihydropyridine-sensitive L-type Ca2+ channels were detectable. Our data are consistent with the hypothesis that agrin, released from neurons, controls the maturation of the excitation-contraction coupling mechanism and that this effect is due to modulation of both RyRs and L-type Ca2+ channels. Thus, a novel role for neural agrin in skeletal muscle maturation is proposed.
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