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Miyairi Y, Ohkawara B, Sato A, Sawada R, Ishii H, Tomita H, Inoue T, Nakashima H, Ito M, Masuda A, Hosono Y, Imagama S, Ohno K. A class of chemical compounds enhances clustering of muscle nicotinic acetylcholine receptor in cultured myogenic cells. Biochem Biophys Res Commun 2024; 731:150400. [PMID: 39024975 DOI: 10.1016/j.bbrc.2024.150400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/25/2024] [Accepted: 07/12/2024] [Indexed: 07/20/2024]
Abstract
Neuromuscular signal transmission is affected in various diseases including myasthenia gravis, congenital myasthenic syndromes, and sarcopenia. We used an ATF2-luciferase system to monitor the phosphorylation of MuSK in HEK293 cells introduced with MUSK and LRP4 cDNAs to find novel chemical compounds that enhanced agrin-mediated acetylcholine receptor (AChR) clustering. Four compounds with similar chemical structures carrying benzene rings and heterocyclic rings increased the luciferase activities 8- to 30-folds, and two of them showed continuously graded dose dependence. The effects were higher than that of disulfiram, a clinically available aldehyde dehydrogenase inhibitor, which we identified to be the most competent preapproved drug to enhance ATF2-luciferase activity in the same assay system. In C2C12 myotubes, all the compounds increased the area, intensity, length, and number of AChR clusters. Three of the four compounds increased the phosphorylation of MuSK, but not of Dok7, JNK. ERK, or p38. Monitoring cell toxicity using the neurite elongation of NSC34 neuronal cells as a surrogate marker showed that all the compounds had no effects on the neurite elongation up to 1 μM. Extensive docking simulation and binding structure prediction of the four compounds with all available human proteins using AutoDock Vina and DiffDock showed that the four compounds were unlikely to directly bind to MuSK or Dok7, and the exact target remained unknown. The identified compounds are expected to serve as a seed to develop a novel therapeutic agent to treat defective NMJ signal transmission.
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Affiliation(s)
- Yuichi Miyairi
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Ayato Sato
- Institute for Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan; Center for One Medicine Innovative Translational Research (COMIT), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Ryusuke Sawada
- Department of Pharmacology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Hisao Ishii
- Department of Hand Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Hiroyuki Tomita
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Taro Inoue
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Hiroaki Nakashima
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Yasuyuki Hosono
- Department of Pharmacology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Shiro Imagama
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan; Graduate School of Nutritoinal Sciencess, Nagoya University of Arts and Sciences, 57 Takenoyama, Iwasaki, Nisshin, 470-0196, Japan.
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Gros K, Matkovič U, Parato G, Miš K, Luin E, Bernareggi A, Sciancalepore M, Marš T, Lorenzon P, Pirkmajer S. Neuronal Agrin Promotes Proliferation of Primary Human Myoblasts in an Age-Dependent Manner. Int J Mol Sci 2022; 23:ijms231911784. [PMID: 36233091 PMCID: PMC9570459 DOI: 10.3390/ijms231911784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/06/2022] [Accepted: 09/22/2022] [Indexed: 12/02/2022] Open
Abstract
Neuronal agrin, a heparan sulphate proteoglycan secreted by the α-motor neurons, promotes the formation and maintenance of the neuromuscular junction by binding to Lrp4 and activating muscle-specific kinase (MuSK). Neuronal agrin also promotes myogenesis by enhancing differentiation and maturation of myotubes, but its effect on proliferating human myoblasts, which are often considered to be unresponsive to agrin, remains unclear. Using primary human myoblasts, we determined that neuronal agrin induced transient dephosphorylation of ERK1/2, while c-Abl, STAT3, and focal adhesion kinase were unresponsive. Gene silencing of Lrp4 and MuSK markedly reduced the BrdU incorporation, suggesting the functional importance of the Lrp4/MuSK complex for myoblast proliferation. Acute and chronic treatments with neuronal agrin increased the proliferation of human myoblasts in old donors, but they did not affect the proliferation of myoblasts in young donors. The C-terminal fragment of agrin which lacks the Lrp4-binding site and cannot activate MuSK had a similar age-dependent effect, indicating that the age-dependent signalling pathways activated by neuronal agrin involve the Lrp4/MuSK receptor complex as well as an Lrp4/MuSK-independent pathway which remained unknown. Collectively, our results highlight an age-dependent role for neuronal agrin in promoting the proliferation of human myoblasts.
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Affiliation(s)
- Katarina Gros
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Urška Matkovič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Giulia Parato
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Elisa Luin
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Annalisa Bernareggi
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Marina Sciancalepore
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Tomaž Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Paola Lorenzon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
- Correspondence: (P.L.); (S.P.)
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Correspondence: (P.L.); (S.P.)
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Rimer M. Extracellular signal-regulated kinases 1 and 2 regulate neuromuscular junction and myofiber phenotypes in mammalian skeletal muscle. Neurosci Lett 2019; 715:134671. [PMID: 31805372 DOI: 10.1016/j.neulet.2019.134671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/27/2019] [Accepted: 11/30/2019] [Indexed: 02/06/2023]
Abstract
The neuromuscular junction is the synapse between a motor neuron of the spinal cord and a skeletal muscle fiber in the periphery. Reciprocal interactions between these excitable cells, and between them and others cell types present within the muscle tissue, shape the development, homeostasis and plasticity of skeletal muscle. An important aim in the field is to understand the molecular mechanisms underlying these cellular interactions, which include identifying the nature of the signals and receptors involved but also of the downstream intracellular signaling cascades elicited by them. This review focuses on work that shows that skeletal muscle fiber-derived extracellular signal-regulated kinases 1 and 2 (ERK1/2), ubiquitous and prototypical intracellular mitogen-activated protein kinases, have modulatory roles in the maintenance of the neuromuscular synapse and in the acquisition and preservation of fiber type identity in skeletal muscle.
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Affiliation(s)
- Mendell Rimer
- Department of Neuroscience & Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center and Texas A&M Institute for Neuroscience, Bryan, TX 77807 USA.
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Gartz Hanson M, Niswander LA. Rectification of muscle and nerve deficits in paralyzed ryanodine receptor type 1 mutant embryos. Dev Biol 2015; 404:76-87. [PMID: 26025922 DOI: 10.1016/j.ydbio.2015.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/21/2015] [Accepted: 05/22/2015] [Indexed: 02/05/2023]
Abstract
Locomotion and respiration require motor axon connectivity and activation of the neuromuscular junction (NMJ). Through a forward genetic screen for muscle weakness, we recently reported an allele of ryanodine receptor type 1 (Ryr1(AG)). Here we reveal a role for functional RyR1 during acetylcholine receptor (AChR) cluster formation and embryonic synaptic transmission. Ryr1(AG) homozygous embryos are non-motile. Motor axons extend past AChR clusters and enlarged AChR clusters are found under fasciculated nerves. Using physiological and pharmacological methods, we show that contractility can be resumed through the masking of a potassium leak, and evoked vesicular release can be resumed via bypassing the defect in RyR1 induced calcium release. Moreover, we show the involvement of ryanodine receptors in presynaptic release at the NMJ. This data provides evidence of a role for RyR1 on both the pre- and postsynaptic sides of the NMJ.
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Affiliation(s)
- M Gartz Hanson
- Department of Pediatrics University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, United States.
| | - Lee A Niswander
- Department of Pediatrics University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, United States
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Muscle-derived extracellular signal-regulated kinases 1 and 2 are required for the maintenance of adult myofibers and their neuromuscular junctions. Mol Cell Biol 2015; 35:1238-53. [PMID: 25605336 DOI: 10.1128/mcb.01071-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Ras-extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway appears to be important for the development, maintenance, aging, and pathology of mammalian skeletal muscle. Yet no gene targeting of Erk1/2 in muscle fibers in vivo has been reported to date. We combined a germ line Erk1 mutation with Cre-loxP Erk2 inactivation in skeletal muscle to produce, for the first time, mice lacking ERK1/2 selectively in skeletal myofibers. Animals lacking muscle ERK1/2 displayed stunted postnatal growth, muscle weakness, and a shorter life span. Their muscles examined in this study, sternomastoid and tibialis anterior, displayed fragmented neuromuscular synapses and a mixture of modest fiber atrophy and loss but failed to show major changes in fiber type composition or absence of cell surface dystrophin. Whereas the lack of only ERK1 had no effects on the phenotypes studied, the lack of myofiber ERK2 explained synaptic fragmentation in the sternomastoid but not the tibialis anterior and a decrease in the expression of the acetylcholine receptor (AChR) epsilon subunit gene mRNA in both muscles. A reduction in AChR protein was documented in line with the above mRNA results. Evidence of partial denervation was found in the sternomastoid but not the tibialis anterior. Thus, myofiber ERK1/2 are differentially required for the maintenance of myofibers and neuromuscular synapses in adult mice.
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Hanson MG, Niswander LA. An explant muscle model to examine the refinement of the synaptic landscape. J Neurosci Methods 2014; 238:95-104. [PMID: 25251554 DOI: 10.1016/j.jneumeth.2014.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 08/27/2014] [Accepted: 09/12/2014] [Indexed: 01/14/2023]
Abstract
Signals from nerve and muscle regulate the formation of synapses. Transgenic mouse models and muscle cell cultures have elucidated the molecular mechanisms required for aggregation and stabilization of synaptic structures. However, far less is known about the molecular pathways involved in redistribution of muscle synaptic components. Here we established a physiologically viable whole-muscle embryonic explant system, in the presence or absence of the nerve, which demonstrates the synaptic landscape is dynamic and malleable. Manipulations of factors intrinsic to the muscle or extrinsically provided by the nerve illustrate vital functions during formation, redistribution and elimination of acetylcholine receptor (AChR) clusters. In particular, RyR1 activity is an important mediator of these functions. This physiologically relevant and readily accessible explant system provides a new approach to genetically uncouple nerve-derived signals and for manipulation via signaling molecules, drugs, and electrical stimulation to examine early formation of the neuromuscular circuit.
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Affiliation(s)
- Martin Gartz Hanson
- Howard Hughes Medical Institute, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, United States.
| | - Lee A Niswander
- Howard Hughes Medical Institute, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, United States
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Chao T, Frump D, Lin M, Caiozzo VJ, Mozaffar T, Steward O, Gupta R. Matrix metalloproteinase 3 deletion preserves denervated motor endplates after traumatic nerve injury. Ann Neurol 2012; 73:210-23. [DOI: 10.1002/ana.23781] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/29/2012] [Accepted: 09/24/2012] [Indexed: 12/13/2022]
Affiliation(s)
- Tom Chao
- Department of Orthopaedic Surgery; University of California; Irvine, Irvine; CA
| | - Derek Frump
- Department of Orthopaedic Surgery; University of California; Irvine, Irvine; CA
| | - Michael Lin
- Department of Orthopaedic Surgery; University of California; Irvine, Irvine; CA
| | - Vincent J. Caiozzo
- Department of Orthopaedic Surgery; University of California; Irvine, Irvine; CA
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Abstract
Agrin, an extracellular matrix protein belonging to the heterogeneous family of heparan sulfate proteoglycans (HSPGs), is expressed by cells of the hematopoietic system but its role in leukocyte biology is not yet clear. Here we demonstrate that agrin has a crucial, nonredundant role in myeloid cell development and functions. We have identified lineage-specific alterations that affect maturation, survival and properties of agrin-deficient monocytic cells, and occur at stages later than stem cell precursors. Our data indicate that the cell-autonomous signals delivered by agrin are sensed by macrophages through the α-DC (DG) receptor and lead to the activation of signaling pathways resulting in rearrangements of the actin cytoskeleton during the phagocytic synapse formation and phosphorylation of extracellular signal-regulated kinases (Erk 1/2). Altogether, these data identify agrin as a novel player of innate immunity.
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Agrin triggers the clustering of raft-associated acetylcholine receptors through actin cytoskeleton reorganization. Biol Cell 2011; 103:287-301. [PMID: 21524273 DOI: 10.1042/bc20110018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND INFORMATION Cholesterol/sphingolipid-rich membrane microdomains or membrane rafts have been implicated in various aspects of receptor function such as activation, trafficking and synapse localization. More specifically in muscle, membrane rafts are involved in AChR (acetylcholine receptor) clustering triggered by the neural factor agrin, a mechanism considered integral to NMJ (neuromuscular junction) formation. In addition, actin polymerization is required for the formation and stabilization of AChR clusters in muscle fibres. Since membrane rafts are platforms sustaining actin nucleation, we hypothesize that these microdomains provide the suitable microenvironment favouring agrin/MuSK (muscle-specific kinase) signalling, eliciting in turn actin cytoskeleton reorganization and AChR clustering. However, the identity of the signalling pathways operating through these microdomains still remains unclear. RESULTS In this work, we attempted to identify the interactions between membrane raft components and cortical skeleton that regulate, upon signalling by agrin, the assembly and stabilization of synaptic proteins of the postsynaptic membrane domain at the NMJ. We provide evidence that in C2C12 myotubes, agrin triggers the association of a subset of membrane rafts enriched in AChR, the -MuSK and Cdc42 (cell division cycle 42) to the actin cytoskeleton. Disruption of the liquid-ordered phase by methyl-β-cyclodextrin abolished this association. We further show that actin and the actin-nucleation factors, N-WASP (neuronal Wiscott-Aldrich syndrome protein) and Arp2/3 (actin-related protein 2/3) are transiently associated with rafts on agrin engagement. Consistent with these observations, pharmacological inhibition of N-WASP activity perturbed agrin-elicited AChR clustering. Finally, immunoelectron microscopic analyses of myotube membrane uncovered that AChRs were constitutively associated with raft nanodomains at steady state that progressively coalesced on agrin activation. These rearrangements of membrane domains correlated with the reorganization of cortical actin cytoskeleton through concomitant and transient recruitment of the Arp2/3 complex to AChR-enriched rafts. CONCLUSIONS The present observations support the notion that membrane rafts are involved in AChR clustering by promoting local actin cytoskeleton reorganization through the recruitment of effectors of the agrin/MuSK signalling cascade. These mechanisms are believed to play an important role in vivo in the formation of the NMJ.
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Rimer M. Emerging roles for MAP kinases in agrin signaling. Commun Integr Biol 2011; 4:143-6. [PMID: 21655426 DOI: 10.4161/cib.4.2.14357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 11/19/2022] Open
Abstract
Information between neurons and the target cells they innervate passes through sites of functional contact called synapses. How synapses form and are altered by sensory or cognitive experience is central to understand nervous system function. Studies of synapse formation and plasticity have concentrated on a few "model" synapses. The vertebrate neuromuscular junction (NMJ), the synapse between a motoneuron in the spinal cord and a skeletal muscle fiber, is one such model synapse. The extracellular matrix proteoglycan agrin plays an essential organizing role at the NMJ. Agrin is also present at some synapses in the brain and in other organs in the periphery, but its function outside the NMJ is unclear. The core signaling pathway for agrin at the NMJ, which is still incompletely defined, includes molecules specifically involved in this cascade and molecules used in other signaling pathways in many cells. Mitogen-activated protein kinases (MAPKs) are evolutionarily conserved components of intracellular signaling modules that control a myriad of cellular processes. This article reviews emerging evidence that suggests that MAPKs are involved in agrin signaling at the NMJ and in the putative functions of agrin in the formation of a subset of synapses in the brain.
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Affiliation(s)
- Mendell Rimer
- Department of Neuroscience & Experimental Therapeutics; College of Medicine; Texas A&M Health Science Center; College Station, TX USA
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