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Colin-Pierre C, El Baraka O, Danoux L, Bardey V, André V, Ramont L, Brézillon S. Regulation of stem cell fate by HSPGs: implication in hair follicle cycling. NPJ Regen Med 2022; 7:77. [PMID: 36577752 PMCID: PMC9797564 DOI: 10.1038/s41536-022-00267-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 11/30/2022] [Indexed: 12/29/2022] Open
Abstract
Heparan sulfate proteoglycans (HSPGs) are part of proteoglycan family. They are composed of heparan sulfate (HS)-type glycosaminoglycan (GAG) chains covalently linked to a core protein. By interacting with growth factors and/or receptors, they regulate numerous pathways including Wnt, hedgehog (Hh), bone morphogenic protein (BMP) and fibroblast growth factor (FGF) pathways. They act as inhibitor or activator of these pathways to modulate embryonic and adult stem cell fate during organ morphogenesis, regeneration and homeostasis. This review summarizes the knowledge on HSPG structure and classification and explores several signaling pathways regulated by HSPGs in stem cell fate. A specific focus on hair follicle stem cell fate and the possibility to target HSPGs in order to tackle hair loss are discussed in more dermatological and cosmeceutical perspectives.
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Affiliation(s)
- Charlie Colin-Pierre
- Université de Reims Champagne-Ardenne, SFR CAP-Santé (FED 4231), Laboratoire de Biochimie Médicale et Biologie Moléculaire, Reims, France.
- CNRS UMR 7369, Matrice Extracellulaire et Dynamique Cellulaire-MEDyC, Reims, France.
- BASF Beauty Care Solutions France SAS, Pulnoy, France.
| | | | - Louis Danoux
- BASF Beauty Care Solutions France SAS, Pulnoy, France
| | | | - Valérie André
- BASF Beauty Care Solutions France SAS, Pulnoy, France
| | - Laurent Ramont
- Université de Reims Champagne-Ardenne, SFR CAP-Santé (FED 4231), Laboratoire de Biochimie Médicale et Biologie Moléculaire, Reims, France
- CNRS UMR 7369, Matrice Extracellulaire et Dynamique Cellulaire-MEDyC, Reims, France
- CHU de Reims, Service Biochimie-Pharmacologie-Toxicologie, Reims, France
| | - Stéphane Brézillon
- Université de Reims Champagne-Ardenne, SFR CAP-Santé (FED 4231), Laboratoire de Biochimie Médicale et Biologie Moléculaire, Reims, France
- CNRS UMR 7369, Matrice Extracellulaire et Dynamique Cellulaire-MEDyC, Reims, France
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Luttrell SM, Smith AST, Mack DL. Creating stem cell-derived neuromuscular junctions in vitro. Muscle Nerve 2021; 64:388-403. [PMID: 34328673 PMCID: PMC9292444 DOI: 10.1002/mus.27360] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/28/2021] [Accepted: 06/21/2021] [Indexed: 12/14/2022]
Abstract
Recent development of novel therapies has improved mobility and quality of life for people suffering from inheritable neuromuscular disorders. Despite this progress, the majority of neuromuscular disorders are still incurable, in part due to a lack of predictive models of neuromuscular junction (NMJ) breakdown. Improvement of predictive models of a human NMJ would be transformative in terms of expanding our understanding of the mechanisms that underpin development, maintenance, and disease, and as a testbed with which to evaluate novel therapeutics. Induced pluripotent stem cells (iPSCs) are emerging as a clinically relevant and non‐invasive cell source to create human NMJs to study synaptic development and maturation, as well as disease modeling and drug discovery. This review will highlight the recent advances and remaining challenges to generating an NMJ capable of eliciting contraction of stem cell‐derived skeletal muscle in vitro. We explore the advantages and shortcomings of traditional NMJ culturing platforms, as well as the pioneering technologies and novel, biomimetic culturing systems currently in use to guide development and maturation of the neuromuscular synapse and extracellular microenvironment. Then, we will explore how this NMJ‐in‐a‐dish can be used to study normal assembly and function of the efferent portion of the neuromuscular arc, and how neuromuscular disease‐causing mutations disrupt structure, signaling, and function.
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Affiliation(s)
- Shawn M Luttrell
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA
| | - Alec S T Smith
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA.,Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - David L Mack
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA.,Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
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3
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Insights into Potential Targets for Therapeutic Intervention in Epilepsy. Int J Mol Sci 2020; 21:ijms21228573. [PMID: 33202963 PMCID: PMC7697405 DOI: 10.3390/ijms21228573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.
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Takamori M. Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability. Front Mol Neurosci 2020; 13:86. [PMID: 32547365 PMCID: PMC7272578 DOI: 10.3389/fnmol.2020.00086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca2+ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.
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Abstract
Thirty to fifty percent of patients with acetylcholine receptor (AChR) antibody (Ab)-negative myasthenia gravis (MG) have Abs to muscle specific kinase (MuSK) and are referred to as having MuSK-MG. MuSK is a 100 kD single-pass post-synaptic transmembrane receptor tyrosine kinase crucial to the development and maintenance of the neuromuscular junction. The Abs in MuSK-MG are predominantly of the IgG4 immunoglobulin subclass. MuSK-MG differs from AChR-MG, in exhibiting more focal muscle involvement, including neck, shoulder, facial and bulbar-innervated muscles, as well as wasting of the involved muscles. MuSK-MG is highly associated with the HLA DR14-DQ5 haplotype and occurs predominantly in females with onset in the fourth decade of life. Some of the standard treatments of AChR-MG have been found to have limited effectiveness in MuSK-MG, including thymectomy and cholinesterase inhibitors. Therefore, current treatment involves immunosuppression, primarily by corticosteroids. In addition, patients respond especially well to B cell depletion agents, e.g., rituximab, with long-term remissions. Future treatments will likely derive from the ongoing analysis of the pathogenic mechanisms underlying this disease, including histologic and physiologic studies of the neuromuscular junction in patients as well as information derived from the development and study of animal models of the disease.
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Affiliation(s)
| | - David P. Richman
- Department of Neurology, University of California, Davis, Davis, CA, United States
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Signal Exchange through Extracellular Vesicles in Neuromuscular Junction Establishment and Maintenance: From Physiology to Pathology. Int J Mol Sci 2019; 20:ijms20112804. [PMID: 31181747 PMCID: PMC6600513 DOI: 10.3390/ijms20112804] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 06/06/2019] [Indexed: 12/11/2022] Open
Abstract
Neuromuscular junction (NMJ) formation involves morphological changes both in motor terminals and muscle membrane. The molecular mechanisms leading to NMJ formation and maintenance have not yet been fully elucidated. During the last decade, it has become clear that virtually all cells release different types of extracellular vesicles (EVs), which can be taken up by nearby or distant cells modulating their activity. Initially, EVs were associated to a mechanism involved in the elimination of unwanted material; subsequent evidence demonstrated that exosomes, and more in general EVs, play a key role in intercellular communication by transferring proteins, lipids, DNA and RNA to target cells. Recently, EVs have emerged as potent carriers for Wnt, bone morphogenetic protein, miRNA secretion and extracellular traveling. Convincing evidence demonstrates that presynaptic terminals release exosomes that are taken up by muscle cells, and these exosomes can modulate synaptic plasticity in the recipient muscle cell in vivo. Furthermore, recent data highlighted that EVs could also be a potential cause of neurodegenerative disorders. Indeed, mutant SOD1, TDP-43 and FUS/TLS can be secreted by neural cells packaged into EVs and enter in neighboring neural cells, contributing to the onset and severity of the disease.
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Shi Y, Li Q, Shao Z. Wnts Promote Synaptic Assembly Through T-Cell Specific Transcription Factors in Caenorhabditis elegans. Front Mol Neurosci 2018; 11:194. [PMID: 29962933 PMCID: PMC6013564 DOI: 10.3389/fnmol.2018.00194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/16/2018] [Indexed: 12/19/2022] Open
Abstract
Synapses are specialized neuronal connections essential for neuronal function. Defects in synaptic assembly or maintenance usually lead to various neurological disorders. Synaptic assembly is regulated by secreted molecules such as Wnts. Wnts are a large family of conserved glycosylated signaling molecules involved in many aspects of neural development and maintenance. However, the molecular mechanisms by which Wnts regulate synaptic assembly remain elusive due to the large number of ligands/receptors, the diversity of signaling cascades and the complexity of the nervous system. In this study, through genetic manipulation, we uncover that C. elegans Wnt-2 (CWN-2) is required for synaptic development. The CWN-2 signal is required during both embryonic and postembryonic development, in the nervous system and intestine, for promoting synaptic assembly. Furthermore, we provide genetic evidence for CWN-2 promoting synaptogenesis through the Frizzled receptor (FZD) CFZ-2, the Dishevelled (DVL) DSH-2, the β-catenin SYS-1 and the only T-cell specific transcription factor POP-1/TCF. Importantly, it is the first time to report the requirement of a TCF for presynaptic assembly. These findings expand our understanding of the synaptogenic mechanisms and may provide therapeutic insights into Wnt-related neurological disorders.
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Affiliation(s)
- Yanjun Shi
- Department of Neurology, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qian Li
- Department of Neurology, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhiyong Shao
- Department of Neurology, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
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8
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Happe CL, Tenerelli KP, Gromova AK, Kolb F, Engler AJ. Mechanically patterned neuromuscular junctions-in-a-dish have improved functional maturation. Mol Biol Cell 2017; 28:1950-1958. [PMID: 28495800 PMCID: PMC5541845 DOI: 10.1091/mbc.e17-01-0046] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 04/03/2017] [Accepted: 05/02/2017] [Indexed: 12/11/2022] Open
Abstract
Motor neuron (MN) diseases are progressive disorders resulting from degeneration of neuromuscular junctions (NMJs), which form the connection between MNs and muscle fibers. NMJ-in-a-dish models have been developed to examine human MN-associated dysfunction with disease; however such coculture models have randomly oriented myotubes with immature synapses that contract asynchronously. Mechanically patterned (MP) extracellular matrix with alternating soft and stiff stripes improves current NMJ-in-a-dish models by inducing both mouse and human myoblast durotaxis to stripes where they aligned, differentiated, and fused into patterned myotubes. Compared to conventional culture on rigid substrates or unpatterned hydrogels, MP substrates supported increased differentiation and fusion, significantly larger acetylcholine (ACh) receptor clusters, and increased expression of MuSK and Lrp4, two cell surface receptors required for NMJ formation. Robust contractions were observed when mouse myotubes were stimulated by ACh, with twitch duration and frequency most closely resembling those for mature muscle on MP substrates. Fused myotubes, when cocultured with MNs, were able to form even larger NMJs. Thus MP matrices produce more functionally active NMJs-in-a-dish, which could be used to elucidate disease pathology and facilitate drug discovery.
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Affiliation(s)
- Cassandra L Happe
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Kevin P Tenerelli
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Anastasia K Gromova
- Biomedical Sciences Program, University of California, San Diego, La Jolla, CA 92093
| | - Frederic Kolb
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Adam J Engler
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
- Biomedical Sciences Program, University of California, San Diego, La Jolla, CA 92093
- Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
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9
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Regulation of WNT Signaling at the Neuromuscular Junction by the Immunoglobulin Superfamily Protein RIG-3 in Caenorhabditis elegans. Genetics 2017; 206:1521-1534. [PMID: 28515212 PMCID: PMC5500148 DOI: 10.1534/genetics.116.195297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 05/11/2017] [Indexed: 12/17/2022] Open
Abstract
Perturbations in synaptic function could affect the normal behavior of an animal, making it important to understand the regulatory mechanisms of synaptic signaling. Previous work has shown that in Caenorhabditis elegans an immunoglobulin superfamily protein, RIG-3, functions in presynaptic neurons to maintain normal acetylcholine receptor levels at the neuromuscular junction (NMJ). In this study, we elucidate the molecular and functional mechanism of RIG-3. We demonstrate by genetic and BiFC (Bi-molecular Fluorescence Complementation) assays that presynaptic RIG-3 functions by directly interacting with the immunoglobulin domain of the nonconventional Wnt receptor, ROR receptor tyrosine kinase (RTK), CAM-1, which functions in postsynaptic body-wall muscles. This interaction in turn inhibits Wnt/LIN-44 signaling through the ROR/CAM-1 receptor, and allows for maintenance of normal acetylcholine receptor, AChR/ACR-16, levels at the neuromuscular synapse. Further, this work reveals that RIG-3 and ROR/CAM-1 function through the β-catenin/HMP-2 at the NMJ. Taken together, our results demonstrate that RIG-3 functions as an inhibitory molecule of the Wnt/LIN-44 signaling pathway through the RTK, CAM-1.
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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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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: 33] [Impact Index Per Article: 4.1] [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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12
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Etherington SJ, Hong IHK, Wong CJW, Stephens N, Warburton NM. Heterochronic neuromuscular junction development in an Australian marsupial (Macropus fuliginosus
). J Zool (1987) 2016. [DOI: 10.1111/jzo.12367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- S. J. Etherington
- School of Veterinary and Life Sciences; Murdoch University; Murdoch Western Australia Australia
| | - I. H. K. Hong
- School of Veterinary and Life Sciences; Murdoch University; Murdoch Western Australia Australia
| | - C. J. W. Wong
- School of Veterinary and Life Sciences; Murdoch University; Murdoch Western Australia Australia
| | - N. Stephens
- School of Veterinary and Life Sciences; Murdoch University; Murdoch Western Australia Australia
| | - N. M. Warburton
- School of Veterinary and Life Sciences; Murdoch University; Murdoch Western Australia Australia
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13
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Kurimoto S, Jung J, Tapadia M, Lengfeld J, Agalliu D, Waterman M, Mozaffar T, Gupta R. Activation of the Wnt/β-catenin signaling cascade after traumatic nerve injury. Neuroscience 2015; 294:101-8. [PMID: 25743255 DOI: 10.1016/j.neuroscience.2015.02.049] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 12/21/2022]
Abstract
Recent data have shown that preservation of the neuromuscular junction (NMJ) after traumatic nerve injury helps to improve functional recovery with surgical repair via matrix metalloproteinase-3 (MMP3) blockade. As such, we sought to explore additional pathways that may augment this response. Wnt3a has been shown to inhibit acetylcholine receptor (AChR) clustering via β-catenin-dependent signaling in the development of the NMJ. Therefore, we hypothesized that Wnt3a and β-catenin are associated with NMJ destabilization following traumatic denervation. A critical size nerve defect was created by excising a 10-mm segment of the sciatic nerve in mice. Denervated muscles were then harvested at multiple time points for immunofluorescence staining, quantitative real-time PCR, and western blot analysis for Wnt3a and β-catenin levels. Moreover, a novel Wnt/β-catenin transgenic reporter mouse line was utilized to support our hypothesis of Wnt activation after traumatic nerve injury. The expression of Wnt3a mRNA was significantly increased by 2 weeks post-injury and remained upregulated for 2 months. Additionally, β-catenin was activated at 2 months post-injury relative to controls. Correspondingly, immunohistochemical analysis of denervated transgenic mouse line TCF/Lef:H2B-GFP muscles demonstrated that the number of GFP-positive cells was increased at the motor endplate band. These collective data support that post-synaptic AChRs destabilize after denervation by a process that involves the Wnt/β-catenin pathway. As such, this pathway serves as a potential therapeutic target to prevent the motor endplate degeneration that occurs following traumatic nerve injury.
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Affiliation(s)
- S Kurimoto
- Department of Orthopaedic Surgery, University of California, Irvine, CA 92697, USA; Department of Hand Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-Cho, Showa-Ku, Nagoya 466-8550, Japan
| | - J Jung
- Department of Orthopaedic Surgery, University of California, Irvine, CA 92697, USA
| | - M Tapadia
- Department of Orthopaedic Surgery, University of California, Irvine, CA 92697, USA
| | - J Lengfeld
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - D Agalliu
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - M Waterman
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, USA
| | - T Mozaffar
- Department of Orthopaedic Surgery, University of California, Irvine, CA 92697, USA; Department of Neurology, University of California, Irvine, CA 92697, USA
| | - R Gupta
- Department of Orthopaedic Surgery, University of California, Irvine, CA 92697, USA; Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA; Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA.
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14
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Osses N, Henríquez JP. Bone morphogenetic protein signaling in vertebrate motor neurons and neuromuscular communication. Front Cell Neurosci 2015; 8:453. [PMID: 25674047 PMCID: PMC4307192 DOI: 10.3389/fncel.2014.00453] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/15/2014] [Indexed: 01/28/2023] Open
Abstract
An accurate communication between motor neurons and skeletal muscle fibers is required for the proper assembly, growth and maintenance of neuromuscular junctions (NMJs). Several signaling and extracellular matrix molecules play stimulatory and inhibitory roles on the assembly of functional synapses. Studies in Drosophila have revealed crucial functions for early morphogens, such as members of the Wnt and Bone Morphogenetic Proteins (BMP) signaling pathways, during the assembly and maturation of the NMJ. Here, we bring together recent findings that led us to propose that BMPs also work in vertebrate organisms as diffusible cues to communicate motor neurons and skeletal muscles.
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Affiliation(s)
- Nelson Osses
- BMP Research Group, Institute of Chemistry, Faculty of Sciences, Pontificia Universidad Católica de Valparaíso Valparaíso, Chile
| | - Juan P Henríquez
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción Concepción, Chile
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Bainbridge TW, DeAlmeida VI, Izrael-Tomasevic A, Chalouni C, Pan B, Goldsmith J, Schoen AP, Quiñones GA, Kelly R, Lill JR, Sandoval W, Costa M, Polakis P, Arnott D, Rubinfeld B, Ernst JA. Evolutionary divergence in the catalytic activity of the CAM-1, ROR1 and ROR2 kinase domains. PLoS One 2014; 9:e102695. [PMID: 25029443 PMCID: PMC4100928 DOI: 10.1371/journal.pone.0102695] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/23/2014] [Indexed: 12/15/2022] Open
Abstract
Receptor tyrosine kinase-like orphan receptors (ROR) 1 and 2 are atypical members of the receptor tyrosine kinase (RTK) family and have been associated with several human diseases. The vertebrate RORs contain an ATP binding domain that deviates from the consensus amino acid sequence, although the impact of this deviation on catalytic activity is not known and the kinase function of these receptors remains controversial. Recently, ROR2 was shown to signal through a Wnt responsive, β-catenin independent pathway and suppress a canonical Wnt/β-catenin signal. In this work we demonstrate that both ROR1 and ROR2 kinase domains are catalytically deficient while CAM-1, the C. elegans homolog of ROR, has an active tyrosine kinase domain, suggesting a divergence in the signaling processes of the ROR family during evolution. In addition, we show that substitution of the non-consensus residues from ROR1 or ROR2 into CAM-1 and MuSK markedly reduce kinase activity, while restoration of the consensus residues in ROR does not restore robust kinase function. We further demonstrate that the membrane-bound extracellular domain alone of either ROR1 or ROR2 is sufficient for suppression of canonical Wnt3a signaling, and that this domain can also enhance Wnt5a suppression of Wnt3a signaling. Based on these data, we conclude that human ROR1 and ROR2 are RTK-like pseudokinases.
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Affiliation(s)
- Travis W. Bainbridge
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Venita I. DeAlmeida
- Department of Cancer Targets, Genentech, Inc., South San Francisco, California, United States of America
| | - Anita Izrael-Tomasevic
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Cécile Chalouni
- Center for Advanced Light Microscopy, Genentech, Inc., South San Francisco, California, United States of America
| | - Borlan Pan
- Department of Structural Biology, Genentech, Inc., South San Francisco, California, United States of America
| | - Joshua Goldsmith
- Department of Cancer Targets, Genentech, Inc., South San Francisco, California, United States of America
| | - Alia P. Schoen
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Gabriel A. Quiñones
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Ryan Kelly
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Jennie R. Lill
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Wendy Sandoval
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Mike Costa
- Department of Cancer Targets, Genentech, Inc., South San Francisco, California, United States of America
| | - Paul Polakis
- Department of Cancer Targets, Genentech, Inc., South San Francisco, California, United States of America
| | - David Arnott
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Bonnee Rubinfeld
- Department of Cancer Targets, Genentech, Inc., South San Francisco, California, United States of America
| | - James A. Ernst
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, California, United States of America
- * E-mail:
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Avilés EC, Pinto C, Hanna P, Ojeda J, Pérez V, De Ferrari GV, Zamorano P, Albistur M, Sandoval D, Henríquez JP. Frizzled-9 impairs acetylcholine receptor clustering in skeletal muscle cells. Front Cell Neurosci 2014; 8:110. [PMID: 24860427 PMCID: PMC4029016 DOI: 10.3389/fncel.2014.00110] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 03/28/2014] [Indexed: 11/13/2022] Open
Abstract
Cumulative evidence indicates that Wnt pathways play crucial and diverse roles to assemble the neuromuscular junction (NMJ), a peripheral synapse characterized by the clustering of acetylcholine receptors (AChR) on postsynaptic densities. The molecular determinants of Wnt effects at the NMJ are still to be fully elucidated. We report here that the Wnt receptor Frizzled-9 (Fzd9) is expressed in developing skeletal muscles during NMJ synaptogenesis. In cultured myotubes, gain- and loss-of-function experiments revealed that Fzd9-mediated signaling impairs the AChR-clustering activity of agrin, an organizer of postsynaptic differentiation. Overexpression of Fzd9 induced the cytosolic accumulation of β-catenin, a key regulator of Wnt signaling. Consistently, Fzd9 and β-catenin localize in the postsynaptic domain of embryonic NMJs in vivo. Our findings represent the first evidence pointing to a crucial role of a Fzd-mediated, β-catenin-dependent signaling on the assembly of the vertebrate NMJ.
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Affiliation(s)
- Evelyn C Avilés
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Cristina Pinto
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Patricia Hanna
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Jorge Ojeda
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Viviana Pérez
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Giancarlo V De Ferrari
- Faculty of Biological Sciences, Center for Biomedical Research and FONDAP Center for Genome Regulation, Universidad Andres Bello Santiago, Chile
| | - Pedro Zamorano
- Department of Biomedicine, Universidad de Antofagasta Antofagasta, Chile
| | - Miguel Albistur
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Daniel Sandoval
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Juan P Henríquez
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Millennium Nucleus of Regenerative Biology, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
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Zhao C, Zhang J, Li K, Yang J, Yu H, Duan S, Jiang K, Li X. β-Catenin regulates membrane potential in muscle cells by regulating the α2 subunit of Na,K-ATPase. Eur J Neurosci 2014; 40:2216-24. [PMID: 24674304 DOI: 10.1111/ejn.12564] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/05/2014] [Accepted: 02/18/2014] [Indexed: 01/28/2023]
Abstract
Muscle β-catenin has been shown to play a role in the formation of the neuromuscular junction (NMJ). Our previous studies showed that muscle-specific conditional knockout of β-catenin (HSA-β-cat(-/-) ) results in early postnatal death in mice. To understand the underlying mechanisms, we investigated the electrophysiological properties of muscle cells from HSA-β-cat(-/-) and control mice, and found that, in the absence of muscle β-catenin, the resting membrane potential (RMP) depolarised in muscle cells from the diaphragm, gastrocnemius and extensor digitorum longus muscles. Furthermore, in a primary line of mouse myoblasts (C2C12 cells) transfected with small-interfering RNAs targeting β-catenin, the RMP was depolarised as well. Finally, the expression levels of the α2 subunit of sodium/potassium adenosine triphosphatase were reduced by β-catenin knockdown in vitro or deletion in vivo. These results suggest a possible mechanism underlying the depolarised RMP in the absence of muscle β-catenin, and provide additional evidence supporting a role for β-catenin in the development of NMJs.
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Affiliation(s)
- Congying Zhao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
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18
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Pinto C, Cárdenas P, Osses N, Henríquez JP. Characterization of Wnt/β-catenin and BMP/Smad signaling pathways in an in vitro model of amyotrophic lateral sclerosis. Front Cell Neurosci 2013; 7:239. [PMID: 24348333 PMCID: PMC3847560 DOI: 10.3389/fncel.2013.00239] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/13/2013] [Indexed: 12/11/2022] Open
Abstract
Different pathways activated by morphogens of the early embryonic development, such as the Wnt and the Bone Morphogenetic Protein (BMP) ligands, are involved in diverse physiological and pathological conditions of the nervous system, including neurodegeneration. In this work, we have analyzed the endogenous activity of the canonical Wnt/β-catenin and BMP/Smad-dependent pathways in an in vitro model of amyotrophic lateral sclerosis (ALS), given by motor neuron-like NSC34 cells stably expressing wild-type or G93A mutated forms of human Cu/Zn superoxide dismutase-1 (SOD1). As ALS-derived motor neurons, NSC34 cells expressing mutated hSOD1 show a decreased proliferation rate, are more susceptible to oxidation-induced cell death and display Golgi fragmentation. In addition, they display an impaired ability to induce the expression of the motor neuronal marker Hb9 and, consistently, to morphologically differentiate into a motor neuronal phenotype. Regarding signaling, our data show that the transcriptional activity associated to the Wnt/β-catenin pathway is decreased, a finding possibly associated to the cytosolic aggregation of β-catenin. In turn, the BMP-dependent phosphorylation of Smad1 and the transcriptional activation of the BMP/Smad pathway is increased in the pathologic model. Together, these findings suggest that Wnt/β-catenin and the BMP-dependent pathways could play relevant roles in the neurodegeneration of motor neurons in the context of ALS.
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Affiliation(s)
- Cristina Pinto
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy, Universidad de ConcepciónConcepción, Chile
| | - Pilar Cárdenas
- Institute of Chemistry, Faculty of Sciences, Pontificia Universidad Católica de ValparaísoValparaiso, Chile
| | - Nelson Osses
- Institute of Chemistry, Faculty of Sciences, Pontificia Universidad Católica de ValparaísoValparaiso, Chile
| | - Juan P. Henríquez
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy, Universidad de ConcepciónConcepción, Chile
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19
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Parkinson W, Dear ML, Rushton E, Broadie K. N-glycosylation requirements in neuromuscular synaptogenesis. Development 2013; 140:4970-81. [PMID: 24227656 DOI: 10.1242/dev.099192] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Neural development requires N-glycosylation regulation of intercellular signaling, but the requirements in synaptogenesis have not been well tested. All complex and hybrid N-glycosylation requires MGAT1 (UDP-GlcNAc:α-3-D-mannoside-β1,2-N-acetylglucosaminyl-transferase I) function, and Mgat1 nulls are the most compromised N-glycosylation condition that survive long enough to permit synaptogenesis studies. At the Drosophila neuromuscular junction (NMJ), Mgat1 mutants display selective loss of lectin-defined carbohydrates in the extracellular synaptomatrix, and an accompanying accumulation of the secreted endogenous Mind the gap (MTG) lectin, a key synaptogenesis regulator. Null Mgat1 mutants exhibit strongly overelaborated synaptic structural development, consistent with inhibitory roles for complex/hybrid N-glycans in morphological synaptogenesis, and strengthened functional synapse differentiation, consistent with synaptogenic MTG functions. Synapse molecular composition is surprisingly selectively altered, with decreases in presynaptic active zone Bruchpilot (BRP) and postsynaptic Glutamate receptor subtype B (GLURIIB), but no detectable change in a wide range of other synaptic components. Synaptogenesis is driven by bidirectional trans-synaptic signals that traverse the glycan-rich synaptomatrix, and Mgat1 mutation disrupts both anterograde and retrograde signals, consistent with MTG regulation of trans-synaptic signaling. Downstream of intercellular signaling, pre- and postsynaptic scaffolds are recruited to drive synaptogenesis, and Mgat1 mutants exhibit loss of both classic Discs large 1 (DLG1) and newly defined Lethal (2) giant larvae [L(2)GL] scaffolds. We conclude that MGAT1-dependent N-glycosylation shapes the synaptomatrix carbohydrate environment and endogenous lectin localization within this domain, to modulate retention of trans-synaptic signaling ligands driving synaptic scaffold recruitment during synaptogenesis.
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Affiliation(s)
- William Parkinson
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
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20
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Wnt signaling in skeletal muscle dynamics: myogenesis, neuromuscular synapse and fibrosis. Mol Neurobiol 2013; 49:574-89. [PMID: 24014138 DOI: 10.1007/s12035-013-8540-5] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/15/2013] [Indexed: 12/21/2022]
Abstract
The signaling pathways activated by Wnt ligands are related to a wide range of critical cell functions, such as cell division, migration, and synaptogenesis. Here, we summarize compelling evidence on the role of Wnt signaling on several features of skeletal muscle physiology. We briefly review the role of Wnt pathways on the formation of muscle fibers during prenatal and postnatal myogenesis, highlighting its role on the activation of stem cells of the adult muscles. We also discuss how Wnt signaling regulates the precise formation of neuromuscular synapses, by modulating the differentiation of presynaptic and postsynaptic components, particularly regarding the clustering of acetylcholine receptors on the muscle membrane. In addition, based on previous evidence showing that Wnt pathways are linked to several diseases, such as Alzheimer's and cancer, we address recent studies indicating that Wnt signaling plays a key role in skeletal muscle fibrosis, a disease characterized by an increase in the extracellular matrix components leading to failure in muscle regeneration, tissue disorganization and loss of muscle activity. In this context, we also discuss the possible cross-talk between the Wnt/β-catenin pathway with two other critical profibrotic pathways, transforming growth factor β and connective tissue growth factor, which are potent stimulators of the accumulation of connective tissue, an effect characteristic of the fibrotic condition. As it has emerged in other pathological conditions, we suggests that muscle fibrosis may be a consequence of alterations of Wnt signaling activity.
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Takamori M. Structure of the neuromuscular junction: function and cooperative mechanisms in the synapse. Ann N Y Acad Sci 2013; 1274:14-23. [PMID: 23252893 DOI: 10.1111/j.1749-6632.2012.06784.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
As an overview of the structure of the neuromuscular junction, three items are described focusing on cooperative mechanisms involving the synapse and leading to muscle contraction: (1) presynaptic acetylcholine release regulated by vesicle cycling (exocytosis and endocytosis); the fast-mode of endocytosis requires a large influx of external Ca(2+) and is promoted by the activation of G protein-coupled receptors and receptor tyrosine kinases; (2) postsynaptic acetylcholine receptor clustering mediated by the muscle-specific, Dok7-stimulated tyrosine kinase (MuSK) through two signaling mechanisms: one via agrin-Lrp4-MuSK (Ig1/2 domains) and the second via Wnt-MuSK (Frizzled-like cysteine-rich domain)-adaptor Dishevelled; Wnts/MuSK and Lrp4 direct a retrograde signal to presynaptic differentiation; (3) muscle contractile machinery regulated by Ca(2+) -release and Ca(2+) -influx channels, including the depolarization-activated ryanodine receptor-1 and the receptor- and/or store-operated transient receptor potential canonical. The first mechanism is dysfunctional in Lambert-Eaton myasthenic syndrome, the second in anti-acetylcholine receptor-negative myasthenia gravis (MG), and the third in thymoma-associated MG.
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22
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Kuroda K, Kuang S, Taketo MM, Rudnicki MA. Canonical Wnt signaling induces BMP-4 to specify slow myofibrogenesis of fetal myoblasts. Skelet Muscle 2013; 3:5. [PMID: 23497616 PMCID: PMC3602004 DOI: 10.1186/2044-5040-3-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 02/15/2013] [Indexed: 11/24/2022] Open
Abstract
Background The Wnts are secreted proteins that play important roles in skeletal myogenesis, muscle fiber type diversification, neuromuscular junction formation and muscle stem cell function. How Wnt proteins orchestrate such diverse activities remains poorly understood. Canonical Wnt signaling stabilizes β-catenin, which subsequently translocate to the nucleus to activate the transcription of TCF/LEF family genes. Methods We employed TCF-reporter mice and performed analysis of embryos and of muscle groups. We further isolated fetal myoblasts and performed cell and molecular analyses. Results We found that canonical Wnt signaling is strongly activated during fetal myogenesis and weakly activated in adult muscles limited to the slow myofibers. Muscle-specific transgenic expression of a stabilized β-catenin protein led to increased oxidative myofibers and reduced muscle mass, suggesting that canonical Wnt signaling promotes slow fiber types and inhibits myogenesis. By TCF-luciferase reporter assay, we identified Wnt-1 and Wnt-3a as potent activators of canonical Wnt signaling in myogenic progenitors. Consistent with in vivo data, constitutive overexpression of Wnt-1 or Wnt-3a inhibited the proliferation of both C2C12 and primary myoblasts. Surprisingly, Wnt-1 and Wnt-3a overexpression up-regulated BMP-4, and inhibition of BMP-4 by shRNA or recombinant Noggin protein rescued the myogenic inhibitory effect of Wnt-1 and Wnt-3a. Importantly, Wnt-3a or BMP-4 recombinant proteins promoted slow myosin heavy chain expression during myogenic differentiation of fetal myoblasts. Conclusions These results demonstrate a novel interaction between canonical Wnt and BMP signaling that induces myogenic differentiation towards slow muscle phenotype.
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Affiliation(s)
- Kazuki Kuroda
- Sprott Center for Stem Cell Research, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada.
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The Onecut transcription factor HNF-6 regulates in motor neurons the formation of the neuromuscular junctions. PLoS One 2012; 7:e50509. [PMID: 23227180 PMCID: PMC3515622 DOI: 10.1371/journal.pone.0050509] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 10/22/2012] [Indexed: 02/06/2023] Open
Abstract
The neuromuscular junctions are the specialized synapses whereby spinal motor neurons control the contraction of skeletal muscles. The formation of the neuromuscular junctions is controlled by a complex interplay of multiple mechanisms coordinately activated in motor nerve terminals and in their target myotubes. However, the transcriptional regulators that control in motor neurons the genetic programs involved in neuromuscular junction development remain unknown. Here, we provide evidence that the Onecut transcription factor HNF-6 regulates in motor neurons the formation of the neuromuscular junctions. Indeed, adult Hnf6 mutant mice exhibit hindlimb muscle weakness and abnormal locomotion. This results from defects of hindlimb neuromuscular junctions characterized by an abnormal morphology and defective localization of the synaptic vesicle protein synaptophysin at the motor nerve terminals. These defects are consequences of altered and delayed formation of the neuromuscular junctions in newborn mutant animals. Furthermore, we show that the expression level of numerous regulators of neuromuscular junction formation, namely agrin, neuregulin-2 and TGF-ß receptor II, is downregulated in the spinal motor neurons of Hnf6 mutant newborn animals. Finally, altered formation of neuromuscular junction-like structures in a co-culture model of wildtype myotubes with mutant embryonic spinal cord slices is rescued by recombinant agrin and neuregulin, indicating that depletion in these factors contributes to defective neuromuscular junction development in the absence of HNF-6. Thus, HNF-6 controls in spinal motor neurons a genetic program that coordinates the formation of hindlimb neuromuscular junctions.
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Park M, Shen K. WNTs in synapse formation and neuronal circuitry. EMBO J 2012; 31:2697-704. [PMID: 22617419 DOI: 10.1038/emboj.2012.145] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/20/2012] [Indexed: 11/09/2022] Open
Abstract
Wnt proteins play important roles in wiring neural circuits. Wnts regulate many aspects of neural circuit generation through their receptors and distinct signalling pathways. In this review, we discuss recent findings on the functions of Wnts in various aspects of neural circuit formation, including neuronal polarity, axon guidance, synapse formation, and synaptic plasticity in vertebrate and invertebrate nervous systems.
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Affiliation(s)
- Mikyoung Park
- Center for Functional Connectomics, Brain Science Institute, Seoul, Korea.
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25
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Wnt4 participates in the formation of vertebrate neuromuscular junction. PLoS One 2012; 7:e29976. [PMID: 22253844 PMCID: PMC3257248 DOI: 10.1371/journal.pone.0029976] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/07/2011] [Indexed: 01/27/2023] Open
Abstract
Neuromuscular junction (NMJ) formation requires the highly coordinated communication of several reciprocal signaling processes between motoneurons and their muscle targets. Identification of the early, spatially restricted cues in target recognition at the NMJ is still poorly documented, especially in mammals. Wnt signaling is one of the key pathways regulating synaptic connectivity. Here, we report that Wnt4 contributes to the formation of vertebrate NMJ in vivo. Results from a microarray screen and quantitative RT-PCR demonstrate that Wnt4 expression is regulated during muscle cell differentiation in vitro and muscle development in vivo, being highly expressed when the first synaptic contacts are formed and subsequently downregulated. Analysis of the mouse Wnt4−/− NMJ phenotype reveals profound innervation defects including motor axons overgrowing and bypassing AChR aggregates with 30% of AChR clusters being unapposed by nerve terminals. In addition, loss of Wnt4 function results in a 35% decrease of the number of prepatterned AChR clusters while Wnt4 overexpression in cultured myotubes increases the number of AChR clusters demonstrating that Wnt4 directly affects postsynaptic differentiation. In contrast, muscle structure and the localization of several synaptic proteins including acetylcholinesterase, MuSK and rapsyn are not perturbed in the Wnt4 mutant. Finally, we identify MuSK as a Wnt4 receptor. Wnt4 not only interacts with MuSK ectodomain but also mediates MuSK activation. Taken together our data reveal a new role for Wnt4 in mammalian NMJ formation that could be mediated by MuSK, a key receptor in synaptogenesis.
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Schulte G, Bryja V, Schambony A. 19thActa Physiologicainternational symposium ‘WNT Signaling in Physiology and Disease’- a long way from developmental biology to physiology. Acta Physiol (Oxf) 2011. [DOI: 10.1111/j.1748-1716.2011.02326.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Henríquez JP, Krull CE, Osses N. The Wnt and BMP families of signaling morphogens at the vertebrate neuromuscular junction. Int J Mol Sci 2011; 12:8924-46. [PMID: 22272112 PMCID: PMC3257109 DOI: 10.3390/ijms12128924] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 11/18/2011] [Accepted: 11/22/2011] [Indexed: 11/16/2022] Open
Abstract
The neuromuscular junction has been extensively employed in order to identify crucial determinants of synaptogenesis. At the vertebrate neuromuscular synapse, extracellular matrix and signaling proteins play stimulatory and inhibitory roles on the assembly of functional synapses. Studies in invertebrate species have revealed crucial functions of early morphogens during the assembly and maturation of the neuromuscular junction. Here, we discuss growing evidence addressing the function of Wnt and Bone morphogenetic protein (BMP) signaling pathways at the vertebrate neuromuscular synapse. We focus on the emerging role of Wnt proteins as positive and negative regulators of postsynaptic differentiation. We also address the possible involvement of BMP pathways on motor neuron behavior for the assembly and/or regeneration of the neuromuscular junction.
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Affiliation(s)
- Juan P. Henríquez
- Laboratory of Developmental Neurobiology (LDNB), Department of Cell Biology, Faculty of Biological Sciences, University of Concepcion, and CMA Bio-Bio, Concepcion 4089100, Chile
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +56-41-220-4531; Fax: +56-41-224-5975
| | - Catherine E. Krull
- University of Michigan, 5211 Dental, Ann Arbor, Michigan, MI 48109, USA; E-Mail:
| | - Nelson Osses
- Institute of Chemistry, Faculty of Sciences, Pontificia Universidad Católica de Valparaíso, Valparaiso 2340025, Chile; E-Mail:
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28
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Kilander MBC, Halleskog C, Schulte G. Recombinant WNTs differentially activate β-catenin-dependent and -independent signalling in mouse microglia-like cells. Acta Physiol (Oxf) 2011; 203:363-72. [PMID: 21557822 DOI: 10.1111/j.1748-1716.2011.02324.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIM The objective of this study was to compare the efficacy of different recombinant, commercially available Wingless/Int-1 (WNTs) with regard to WNT/β-catenin signalling, dishevelled (DVL) and G protein activation and the induction of cell proliferation in a microglia-like cell line called N13. METHODS For detection of activated signalling molecules, cell lysates are analysed by immunoblotting. Furthermore, we used a [γ(35)S] GTP binding assay to monitor the exchange of GDP for GTP in heterotrimeric G proteins in N13 membrane preparations. Cell proliferation was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay measuring mitochondrial function, which is proportional to the amount of viable cells. RESULTS Of the WNTs tested (WNT-3A, -4, -5A, -5B, -7A,-9B), only WNT-3A activated WNT/β-catenin signalling in N13 cells. All WNTs induced the formation of phosphorylated and shifted DVL (PS-DVL) and the activation of heterotrimeric G proteins with variable efficacies. WNT-5A and WNT-9B, which had the highest efficacy in the G protein assay, also induced N13 cell proliferation. CONCLUSION WNTs show significant differences in their efficacy to activate β-catenin-dependent and -independent signalling. The WNTs tested are present during maturation of the central nervous system and/or in the adult brain and are thus potential regulators of microglia-mediated neuroinflammation.
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Affiliation(s)
- M B C Kilander
- Section Receptor Biology & Signalling, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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