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Korb A, Tajbakhsh S, Comai GE. Functional specialisation and coordination of myonuclei. Biol Rev Camb Philos Soc 2024; 99:1164-1195. [PMID: 38477382 DOI: 10.1111/brv.13063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 03/14/2024]
Abstract
Myofibres serve as the functional unit for locomotion, with the sarcomere as fundamental subunit. Running the entire length of this structure are hundreds of myonuclei, located at the periphery of the myofibre, juxtaposed to the plasma membrane. Myonuclear specialisation and clustering at the centre and ends of the fibre are known to be essential for muscle contraction, yet the molecular basis of this regionalisation has remained unclear. While the 'myonuclear domain hypothesis' helped explain how myonuclei can independently govern large cytoplasmic territories, novel technologies have provided granularity on the diverse transcriptional programs running simultaneously within the syncytia and added a new perspective on how myonuclei communicate. Building upon this, we explore the critical cellular and molecular sources of transcriptional and functional heterogeneity within myofibres, discussing the impact of intrinsic and extrinsic factors on myonuclear programs. This knowledge provides new insights for understanding muscle development, repair, and disease, but also opens avenues for the development of novel and precise therapeutic approaches.
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Affiliation(s)
- Amaury Korb
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
| | - Shahragim Tajbakhsh
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
| | - Glenda E Comai
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
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2
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Lukowicz-Bedford RM, Eisen JS, Miller AC. Gap-junction-mediated bioelectric signaling required for slow muscle development and function in zebrafish. Curr Biol 2024:S0960-9822(24)00759-0. [PMID: 38936363 DOI: 10.1016/j.cub.2024.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 04/11/2024] [Accepted: 06/04/2024] [Indexed: 06/29/2024]
Abstract
Bioelectric signaling, intercellular communication facilitated by membrane potential and electrochemical coupling, is emerging as a key regulator of animal development. Gap junction (GJ) channels can mediate bioelectric signaling by creating a fast, direct pathway between cells for the movement of ions and other small molecules. In vertebrates, GJ channels are formed by a highly conserved transmembrane protein family called the connexins. The connexin gene family is large and complex, creating challenges in identifying specific connexins that create channels within developing and mature tissues. Using the embryonic zebrafish neuromuscular system as a model, we identify a connexin conserved across vertebrate lineages, gjd4, which encodes the Cx46.8 protein, that mediates bioelectric signaling required for slow muscle development and function. Through mutant analysis and in vivo imaging, we show that gjd4/Cx46.8 creates GJ channels specifically in developing slow muscle cells. Using genetics, pharmacology, and calcium imaging, we find that spinal-cord-generated neural activity is transmitted to developing slow muscle cells, and synchronized activity spreads via gjd4/Cx46.8 GJ channels. Finally, we show that bioelectrical signal propagation within the developing neuromuscular system is required for appropriate myofiber organization and that disruption leads to defects in behavior. Our work reveals a molecular basis for GJ communication among developing muscle cells and reveals how perturbations to bioelectric signaling in the neuromuscular system may contribute to developmental myopathies. Moreover, this work underscores a critical motif of signal propagation between organ systems and highlights the pivotal role of GJ communication in coordinating bioelectric signaling during development.
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Affiliation(s)
| | - Judith S Eisen
- University of Oregon, Institute of Neuroscience, Eugene, OR 97405, USA
| | - Adam C Miller
- University of Oregon, Institute of Neuroscience, Eugene, OR 97405, USA.
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3
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Kenworthy AK. What's past is prologue: FRAP keeps delivering 50 years later. Biophys J 2023; 122:3577-3586. [PMID: 37218127 PMCID: PMC10541474 DOI: 10.1016/j.bpj.2023.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/03/2023] [Accepted: 05/11/2023] [Indexed: 05/24/2023] Open
Abstract
Fluorescence recovery after photobleaching (FRAP) has emerged as one of the most widely utilized techniques to quantify binding and diffusion kinetics of biomolecules in biophysics. Since its inception in the mid-1970s, FRAP has been used to address an enormous array of questions including the characteristic features of lipid rafts, how cells regulate the viscosity of their cytoplasm, and the dynamics of biomolecules inside condensates formed by liquid-liquid phase separation. In this perspective, I briefly summarize the history of the field and discuss why FRAP has proven to be so incredibly versatile and popular. Next, I provide an overview of the extensive body of knowledge that has emerged on best practices for quantitative FRAP data analysis, followed by some recent examples of biological lessons learned using this powerful approach. Finally, I touch on new directions and opportunities for biophysicists to contribute to the continued development of this still-relevant research tool.
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Affiliation(s)
- Anne K Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia.
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4
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Mirouse V. Evolution and developmental functions of the dystrophin-associated protein complex: beyond the idea of a muscle-specific cell adhesion complex. Front Cell Dev Biol 2023; 11:1182524. [PMID: 37384252 PMCID: PMC10293626 DOI: 10.3389/fcell.2023.1182524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/30/2023] [Indexed: 06/30/2023] Open
Abstract
The Dystrophin-Associated Protein Complex (DAPC) is a well-defined and evolutionarily conserved complex in animals. DAPC interacts with the F-actin cytoskeleton via dystrophin, and with the extracellular matrix via the membrane protein dystroglycan. Probably for historical reasons that have linked its discovery to muscular dystrophies, DAPC function is often described as limited to muscle integrity maintenance by providing mechanical robustness, which implies strong cell-extracellular matrix adhesion properties. In this review, phylogenetic and functional data from different vertebrate and invertebrate models will be analyzed and compared to explore the molecular and cellular functions of DAPC, with a specific focus on dystrophin. These data reveals that the evolution paths of DAPC and muscle cells are not intrinsically linked and that many features of dystrophin protein domains have not been identified yet. DAPC adhesive properties also are discussed by reviewing the available evidence of common key features of adhesion complexes, such as complex clustering, force transmission, mechanosensitivity and mechanotransduction. Finally, the review highlights DAPC developmental roles in tissue morphogenesis and basement membrane (BM) assembly that may indicate adhesion-independent functions.
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5
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Milcheva R, Mečiarová I, Todorova K, Dilcheva V, Petkova S, Babál P. Trichinella spiralis (Owen, 1835) Induces Increased Dystrophin Expression in Invaded Cross-striated Muscle. Acta Parasitol 2023:10.1007/s11686-023-00673-2. [PMID: 36988857 DOI: 10.1007/s11686-023-00673-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/08/2023] [Indexed: 03/30/2023]
Abstract
PURPOSE Dystrophin and the dystrophin glycoprotein complex serve as a cytoskeletal integrator, critical for muscle membrane stability. The aim of the present study was to clarify the expression of dystrophin protein and mRNA in the skeletal muscle tissue during the muscle phase of trichinellosis in mice. METHODS Muscle tissue was collected from mice experimentally infected with Trichinella spiralis at days 0, 14 and 40 after infection. The expression of dystrophin in the muscle tissue was investigated by immunohistochemistry with antibodies against three different domains of the protein, and the expression levels of Dys mRNA by real-time PCR. RESULTS The presence of dystrophin protein was increased in the de-differentiating cytoplasm at the early stage of muscle infection and was persisting also in the mature Nurse cell harbouring the parasite. It was accompanied by significantly elevated expression of Dys mRNA at days 14 and 40 after infection. CONCLUSION Our findings indicate that dystrophin plays a role in regeneration of the muscle and in the Nurse cell formation and stability for security of the parasite survival.
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Affiliation(s)
- Rositsa Milcheva
- Institute of Experimental Morphology, Pathology and Anthropology with Museum-Bulgarian Academy of Sciences, "Acad. G. Bonchev'' Str., block 25, 1113, Sofia, Bulgaria.
| | | | - Katerina Todorova
- Institute of Experimental Morphology, Pathology and Anthropology with Museum-Bulgarian Academy of Sciences, "Acad. G. Bonchev'' Str., block 25, 1113, Sofia, Bulgaria
| | - Valeria Dilcheva
- Institute of Experimental Morphology, Pathology and Anthropology with Museum-Bulgarian Academy of Sciences, "Acad. G. Bonchev'' Str., block 25, 1113, Sofia, Bulgaria
| | - Svetlozara Petkova
- Institute of Experimental Morphology, Pathology and Anthropology with Museum-Bulgarian Academy of Sciences, "Acad. G. Bonchev'' Str., block 25, 1113, Sofia, Bulgaria
| | - Pavel Babál
- Institute of Pathological Anatomy, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
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6
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Dystrophin myonuclear domain restoration governs treatment efficacy in dystrophic muscle. Proc Natl Acad Sci U S A 2023; 120:e2206324120. [PMID: 36595689 PMCID: PMC9926233 DOI: 10.1073/pnas.2206324120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Dystrophin is essential for muscle health: its sarcolemmal absence causes the fatal, X-linked condition, Duchenne muscular dystrophy (DMD). However, its normal, spatial organization remains poorly understood, which hinders the interpretation of efficacy of its therapeutic restoration. Using female reporter mice heterozygous for fluorescently tagged dystrophin (DmdEGFP), we here reveal that dystrophin distribution is unexpectedly compartmentalized, being restricted to myonuclear-defined sarcolemmal territories extending ~80 µm, which we called "basal sarcolemmal dystrophin units (BSDUs)." These territories were further specialized at myotendinous junctions, where both Dmd transcripts and dystrophin protein were enriched. Genome-level correction in X-linked muscular dystrophy mice via CRISPR/Cas9 gene editing restored a mosaic of separated dystrophin domains, whereas transcript-level Dmd correction, following treatment with tricyclo-DNA antisense oligonucleotides, restored dystrophin initially at junctions before extending along the entire fiber-with levels ~2% sufficient to moderate the dystrophic process. We conclude that widespread restoration of fiber dystrophin is likely critical for therapeutic success in DMD, perhaps most importantly, at muscle-tendon junctions.
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Tanji M, Wada K, Sakamoto K, Ono Y, Inui M. Digoxigenin-labeled RNA probes for untranslated regions enable the isoform-specific gene expression analysis of myosin heavy chains in whole-mount in situ hybridization. Dev Growth Differ 2023; 65:48-55. [PMID: 36517457 DOI: 10.1111/dgd.12832] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/03/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022]
Abstract
Myosin heavy chains (MyHCs), which are encoded by myosin heavy chain (Myh) genes, are the most abundant proteins in myofiber. Among the 11 sarcomeric Myh isoform genes in the mammalian genome, seven are mainly expressed in skeletal muscle. Myh genes/MyHC proteins share a common role as force producing units with highly conserved sequences, but have distinct spatio-temporal expression patterns. As such, the expression patterns of Myh genes/MyHC proteins are considered as molecular signatures of specific fiber types or the regenerative status of mammalian skeletal muscles. Immunohistochemistry is widely used for identifying MyHC expression patterns; however, this method is costly and is not ideal for whole-mount samples, such as embryos. In situ hybridization (ISH) is another versatile method for the analysis of gene expression, but is not commonly applied for Myh genes, partly because of the highly homologous sequences of Myh genes. Here we demonstrate that an ISH analysis with the untranslated region (UTR) sequence of Myh genes is cost-effective and specific method for analyzing the Myh gene expression in whole-mount samples. Digoxigenin (DIG)-labeled antisense probes for UTR sequences, but not for protein coding sequences, specifically detected the expression patterns of respective Myh isoform genes in both embryo and adult skeletal muscle tissues. UTR probes also revealed the isoform gene-specific polarized localization of Myh mRNAs in embryonic myofibers, which implied a novel mRNA distribution mechanism. Our data suggested that the DIG-labeled UTR probe is a cost-effective and versatile method to specifically detect skeletal muscle Myh genes in a whole-mount analysis.
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Affiliation(s)
- Masafumi Tanji
- Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Keitaro Wada
- Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Keita Sakamoto
- Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Yudai Ono
- Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Masafumi Inui
- Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
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8
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Warrington SJ, Strutt H, Strutt D. Use of Fluorescence Recovery After Photobleaching (FRAP) to Measure In Vivo Dynamics of Cell Junction-Associated Polarity Proteins. Methods Mol Biol 2022; 2438:1-30. [PMID: 35147932 DOI: 10.1007/978-1-0716-2035-9_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Here, we present a detailed protocol for fluorescence recovery after photobleaching (FRAP) to measure the dynamics of junctional populations of proteins in living tissue. Specifically, we describe how to perform FRAP in Drosophila pupal wings on fluorescently tagged core planar polarity proteins, which exhibit relatively slow junctional turnover. We provide a step-by-step practical guide to performing FRAP, and list a series of controls and optimizations to do before conducting a FRAP experiment. Finally, we describe how to present the FRAP data for publication.
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Affiliation(s)
| | - Helen Strutt
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - David Strutt
- School of Biosciences, University of Sheffield, Sheffield, UK.
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9
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Nutraceutical Screening in a Zebrafish Model of Muscular Dystrophy: Gingerol as a Possible Food Aid. Nutrients 2021; 13:nu13030998. [PMID: 33808773 PMCID: PMC8003371 DOI: 10.3390/nu13030998] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/04/2021] [Accepted: 03/16/2021] [Indexed: 12/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin gene, is an inherited neuromuscular disorder that causes loss of muscle mass and motor skills. In the era of genomic medicine, there is still no known cure for DMD. In clinical practice, there is a growing awareness of the possible importance of nutrition in neuromuscular diseases. This is mostly the result of patients’ or caregivers’ empirical reports of how active substances derived from food have led to improved muscle strength and, thus, better quality of life. In this report, we investigate several nutraceutical principles in the sapje strain of zebrafish, a validated model of DMD, in order to identify possible natural products that, if supplemented in the diet, might improve the quality of life of DMD patients. Gingerol, a constituent of fresh ginger, statistically increased the locomotion of mutant larvae and upregulated the expression of heme oxygenase 1, a target gene for therapy aimed at improving dystrophic symptoms. Although three other compounds showed a partial positive effect on locomotor and muscle structure phenotypes, our nutraceutical screening study lent preliminary support to the efficacy and safety only of gingerol. Gingerol could easily be proposed as a dietary supplement in DMD.
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10
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Chen Y, Li J, Zhou Q, Liu Z, Li Q. Hexavalent chromium amplifies the developmental toxicity of graphene oxide during zebrafish embryogenesis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 208:111487. [PMID: 33126181 DOI: 10.1016/j.ecoenv.2020.111487] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
Combined toxicity is a critical issue in risk assessment of contaminants. However, very little is known about the joint effects of graphene oxide (GO, a crucial 2-dimensional carbon material) and hexavalent chromium (Cr6+, a widespread heavy metal), particularly with respect to the critical period of embryogenesis. In this study, the combined toxicity of GO and Cr6+ was evaluated through embryo-larval toxicity test in Danio rerio (zebrafish). Results indicated that the co-exposure of Cr6+ (1 mg/L) and GO (0.01 mg/L) inhibited hatching and spontaneous movement of embryos, but no significant changes were found in the single Cr6+ or GO group. Compared with the single GO or Cr6+ exposure, their co-exposure (GO+Cr6+) significantly enhanced the teratogenicity in a concentration-dependent pattern, and the spinal curvature was observed as the main deformity. GO+Cr6+ changed the protein secondary structures of embryos result of the generation of ROS and oxidative stress. The degradations of vertical myosepta and cartilages were observed in co-exposure group, suggesting that GO+Cr6+ disrupted the development of musculoskeletal system. The genes col11a1a, col2a1a and postnb were down-regulated but the genes acta1b and mmp9 were up-regulated by GO+Cr6+. The interactions between Cr6+ and GO demonstrated that the morphology, structure, and surface properties of GO were modified by Cr6+. The enhanced defects and O-containing groups of GO could trap more β-sheets, induced oxidative stress, disturbed the development of skeletal muscles and cartilages in zebrafish. These data suggested that GO+Cr6+ enhanced their joint toxicity due to the variation of nanoparticle properties. This finding is important for assessing the ecological risk of graphene family nanomaterials in the natural environment.
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Affiliation(s)
- Yuming Chen
- School of Public Health, Xinxiang Medical University, Xinxiang 453003, China
| | - Jitong Li
- Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases/Henan Neural Development Engineering Research Center for Children, Department of Nephrology and Rheumatology, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou 450018, China
| | - Qixing Zhou
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
| | - Zhijie Liu
- School of Public Health, Xinxiang Medical University, Xinxiang 453003, China
| | - Qiong Li
- School of Public Health, Xinxiang Medical University, Xinxiang 453003, China
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11
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Ganassi M, Badodi S, Wanders K, Zammit PS, Hughes SM. Myogenin is an essential regulator of adult myofibre growth and muscle stem cell homeostasis. eLife 2020; 9:e60445. [PMID: 33001028 PMCID: PMC7599067 DOI: 10.7554/elife.60445] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/30/2020] [Indexed: 02/06/2023] Open
Abstract
Growth and maintenance of skeletal muscle fibres depend on coordinated activation and return to quiescence of resident muscle stem cells (MuSCs). The transcription factor Myogenin (Myog) regulates myocyte fusion during development, but its role in adult myogenesis remains unclear. In contrast to mice, myog-/-zebrafish are viable, but have hypotrophic muscles. By isolating adult myofibres with associated MuSCs, we found that myog-/- myofibres have severely reduced nuclear number, but increased myonuclear domain size. Expression of fusogenic genes is decreased, Pax7 upregulated, MuSCs are fivefold more numerous and mis-positioned throughout the length of myog-/-myofibres instead of localising at myofibre ends as in wild-type. Loss of Myog dysregulates mTORC1 signalling, resulting in an 'alerted' state of MuSCs, which display precocious activation and faster cell cycle entry ex vivo, concomitant with myod upregulation. Thus, beyond controlling myocyte fusion, Myog influences the MuSC:niche relationship, demonstrating a multi-level contribution to muscle homeostasis throughout life.
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Affiliation(s)
- Massimo Ganassi
- Randall Centre for Cell and Molecular Biophysics, King’s College LondonLondonUnited Kingdom
| | - Sara Badodi
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of LondonLondonUnited Kingdom
| | - Kees Wanders
- Randall Centre for Cell and Molecular Biophysics, King’s College LondonLondonUnited Kingdom
| | - Peter S Zammit
- Randall Centre for Cell and Molecular Biophysics, King’s College LondonLondonUnited Kingdom
| | - Simon M Hughes
- Randall Centre for Cell and Molecular Biophysics, King’s College LondonLondonUnited Kingdom
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12
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Sear RP. Diffusiophoresis in Cells: A General Nonequilibrium, Nonmotor Mechanism for the Metabolism-Dependent Transport of Particles in Cells. PHYSICAL REVIEW LETTERS 2019; 122:128101. [PMID: 30978101 DOI: 10.1103/physrevlett.122.128101] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/21/2019] [Indexed: 06/09/2023]
Abstract
The more we learn about the cytoplasm of cells, the more we realize that the cytoplasm is not uniform but instead is highly inhomogeneous. In any inhomogeneous solution, there are concentration gradients, and particles move either up or down these gradients due to a mechanism called diffusiophoresis. I estimate that inside metabolically active cells, the dynamics of particles can be strongly accelerated by diffusiophoresis, provided that they are at least tens of nanometers across. The dynamics of smaller objects, such as single proteins, are largely unaffected.
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Affiliation(s)
- Richard P Sear
- Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
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13
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Abstract
Dystrophin is the largest protein isoform (427 kDa) expressed from the gene defective in Duchenne muscular dystrophy, a lethal muscle-wasting and genetically inherited disease. Dystrophin, localized within a cytoplasmic lattice termed costameres, connects the intracellular cytoskeleton of a myofiber through the cell membrane (sarcolemma) to the surrounding extracellular matrix. In spite of its mechanical regulation roles in stabilizing the sarcolemma during muscle contraction, the underlying molecular mechanism is still elusive. Here, we systematically investigated the mechanical stability and kinetics of the force-bearing central domain of human dystrophin that contains 24 spectrin repeats using magnetic tweezers. We show that the stochastic unfolding and refolding of central domain of dystrophin is able to keep the forces below 25 pN over a significant length change up to ∼800 nm in physiological level of pulling speeds. These results suggest that dystrophin may serve as a molecular shock absorber that defines the physiological level of force in the dystrophin-mediated force-transmission pathway during muscle contraction/stretch, thereby stabilizing the sarcolemma.
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Affiliation(s)
- Shimin Le
- Department of Physics, National University of Singapore, Singapore, 117551
| | - Miao Yu
- Mechanobiology Institute, National University of Singapore, Singapore, 117411
| | - Ladislav Hovan
- Mechanobiology Institute, National University of Singapore, Singapore, 117411
| | - Zhihai Zhao
- Department of Physics, National University of Singapore, Singapore, 117551
| | - James Ervasti
- College of Biological Sciences, University of Minnesota, MN, USA, 55455
| | - Jie Yan
- Department of Physics, National University of Singapore, Singapore, 117551
- Mechanobiology Institute, National University of Singapore, Singapore, 117411
- Centre for BioImaging Sciences, National University of Singapore, Singapore, 117546
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14
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Veerapathiran S, Wohland T. Fluorescence techniques in developmental biology. J Biosci 2018; 43:541-553. [PMID: 30002271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Advanced fluorescence techniques, commonly known as the F-techniques, measure the kinetics and the interactions of biomolecules with high sensitivity and spatiotemporal resolution. Applications of the F-techniques, which were initially limited to cells, were further extended to study in vivo protein organization and dynamics in whole organisms. The integration of F-techniques with multi-photon microscopy and light-sheet microscopy widened their applications in the field of developmental biology. It became possible to penetrate the thick tissues of living organisms and obtain good signal-to-noise ratio with reduced photo-induced toxicity. In this review, we discuss the principle and the applications of the three most commonly used F-techniques in developmental biology: Fluorescence Recovery After Photo-bleaching (FRAP), Fo¨ rster Resonance Energy Transfer (FRET), and Fluorescence Correlation and Cross-Correlation Spectroscopy (FCS and FCCS).
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Affiliation(s)
- Sapthaswaran Veerapathiran
- Department of Biological Sciences and NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore
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15
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16
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Delalande O, Molza AE, Dos Santos Morais R, Chéron A, Pollet É, Raguenes-Nicol C, Tascon C, Giudice E, Guilbaud M, Nicolas A, Bondon A, Leturcq F, Férey N, Baaden M, Perez J, Roblin P, Piétri-Rouxel F, Hubert JF, Czjzek M, Le Rumeur E. Dystrophin's central domain forms a complex filament that becomes disorganized by in-frame deletions. J Biol Chem 2018. [PMID: 29535188 DOI: 10.1074/jbc.m117.809798] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Dystrophin, encoded by the DMD gene, is critical for maintaining plasma membrane integrity during muscle contraction events. Mutations in the DMD gene disrupting the reading frame prevent dystrophin production and result in severe Duchenne muscular dystrophy (DMD); in-frame internal deletions allow production of partly functional internally deleted dystrophin and result in less severe Becker muscular dystrophy (BMD). Many known BMD deletions occur in dystrophin's central domain, generally considered to be a monotonous rod-shaped domain based on the knowledge of spectrin family proteins. However, the effects caused by these deletions, ranging from asymptomatic to severe BMD, argue against the central domain serving only as a featureless scaffold. We undertook structural studies combining small-angle X-ray scattering and molecular modeling in an effort to uncover the structure of the central domain, as dystrophin has been refractory to characterization. We show that this domain appears to be a tortuous and complex filament that is profoundly disorganized by the most severe BMD deletion (loss of exons 45-47). Despite the preservation of large parts of the binding site for neuronal nitric oxide synthase (nNOS) in this deletion, computational approaches failed to recreate the association of dystrophin with nNOS. This observation is in agreement with a strong decrease of nNOS immunolocalization in muscle biopsies, a parameter related to the severity of BMD phenotypes. The structural description of the whole dystrophin central domain we present here is a first necessary step to improve the design of microdystrophin constructs toward the goal of a successful gene therapy for DMD.
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Affiliation(s)
- Olivier Delalande
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France,
| | - Anne-Elisabeth Molza
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Raphael Dos Santos Morais
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France.,the Synchrotron SOLEIL, 91190 Saint Aubin, France.,the Laboratoire Léon-Brillouin, UMR 12 CEA-CNRS, Université Paris-Saclay, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Angélique Chéron
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Émeline Pollet
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Céline Raguenes-Nicol
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Christophe Tascon
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Emmanuel Giudice
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Marine Guilbaud
- the Sorbonne Universités UPMC-INSERM-UMRS 97-CNRS FRE 3617, Institut de Myologie, 75013 Paris, France
| | - Aurélie Nicolas
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Arnaud Bondon
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France.,the Université Rennes, CNRS, Institut des Sciences Chimiques de Rennes-UMR 6226, PRISM, 35000 Rennes, France
| | - France Leturcq
- the Sorbonne Universités UPMC-INSERM-UMRS 97-CNRS FRE 3617, Institut de Myologie, 75013 Paris, France.,the AP-HP, Groupe Hospitalier Cochin-Broca-Hôtel Dieu, Laboratoire de Biochimie et Génétique Moléculaire, 75014 Paris, France
| | - Nicolas Férey
- the CNRS UPR3251, Université Paris XI, 91403 Orsay Cedex, France
| | - Marc Baaden
- the CNRS UPR9080, Université Paris Diderot, Sorbonne Paris Cité, 75005 Paris, France
| | - Javier Perez
- the Synchrotron SOLEIL, 91190 Saint Aubin, France
| | - Pierre Roblin
- the Synchrotron SOLEIL, 91190 Saint Aubin, France.,the INRA-Biopolymères, Interaction et Assemblages, 44000 Nantes, France
| | - France Piétri-Rouxel
- the Sorbonne Universités UPMC-INSERM-UMRS 97-CNRS FRE 3617, Institut de Myologie, 75013 Paris, France
| | - Jean-François Hubert
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
| | - Mirjam Czjzek
- the Sorbonne Universités, UPMC Université Paris 06, 75006 Paris, France, and.,the CNRS UMR 8227, Integrative Biology of Marine Models, 29688 Roscoff Cedex, France
| | - Elisabeth Le Rumeur
- From the Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, 35000 Rennes, France
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17
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Abstract
Histone acetyl transferases (HATs) and histone deacetylases (HDAC) control transcription during myogenesis. HDACs promote chromatin condensation, inhibiting gene transcription in muscle progenitor cells until myoblast differentiation is triggered and HDACs are released. HATs, namely CBP/p300, activate myogenic regulatory and elongation factors promoting myogenesis. HDAC inhibitors are known to improve regeneration in dystrophic muscles through follistatin upregulation. However, the potential of directly modulating HATs remains unexplored. We tested this possibility in a well-known zebrafish model of Duchenne muscular dystrophy. Interestingly, CBP/p300 transcripts were found downregulated in the absence of Dystrophin. While investigating CBP rescuing potential we observed that dystrophin-null embryos overexpressing CBP actually never show significant muscle damage, even before a first regeneration cycle could occur. We found that the pan-HDAC inhibitor trichostatin A (TSA) also prevents early muscle damage, however the single HAT CBP is as efficient even in low doses. The HAT domain of CBP is required for its full rescuing ability. Importantly, both CBP and TSA prevent early muscle damage without restoring endogenous CBP/p300 neither increasing follistatin transcripts. This suggests a new mechanism of action of epigenetic regulators protecting dystrophin-null muscle fibres from detaching, independent from the known improvement of regeneration upon damage of HDACs inhibitors. This study builds supporting evidence that epigenetic modulators may play a role in determining the severity of muscle dystrophy, controlling the ability to resist muscle damage. Determining the mode of action leading to muscle protection can potentially lead to new treatment options for muscular dystrophies in the future.
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Affiliation(s)
- Fernanda Bajanca
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Laurence Vandel
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France; Université Clermont Auvergne, CNRS, Inserm, GReD, F-63000 Clermont-Ferrand, France (present address)
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18
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Chow RWY, Vermot J. The rise of photoresponsive protein technologies applications in vivo: a spotlight on zebrafish developmental and cell biology. F1000Res 2017; 6. [PMID: 28413613 PMCID: PMC5389412 DOI: 10.12688/f1000research.10617.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/06/2017] [Indexed: 12/24/2022] Open
Abstract
The zebrafish ( Danio rerio) is a powerful vertebrate model to study cellular and developmental processes in vivo. The optical clarity and their amenability to genetic manipulation make zebrafish a model of choice when it comes to applying optical techniques involving genetically encoded photoresponsive protein technologies. In recent years, a number of fluorescent protein and optogenetic technologies have emerged that allow new ways to visualize, quantify, and perturb developmental dynamics. Here, we explain the principles of these new tools and describe some of their representative applications in zebrafish.
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Affiliation(s)
- Renee Wei-Yan Chow
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique UMR8104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Julien Vermot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique UMR8104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
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19
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Zhao J, Kodippili K, Yue Y, Hakim CH, Wasala L, Pan X, Zhang K, Yang NN, Duan D, Lai Y. Dystrophin contains multiple independent membrane-binding domains. Hum Mol Genet 2016; 25:3647-3653. [PMID: 27378693 DOI: 10.1093/hmg/ddw210] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/14/2016] [Accepted: 06/27/2016] [Indexed: 01/09/2023] Open
Abstract
Dystrophin is a large sub-sarcolemmal protein. Its absence leads to Duchenne muscular dystrophy (DMD). Binding to the sarcolemma is essential for dystrophin to protect muscle from contraction-induced injury. It has long been thought that membrane binding of dystrophin depends on its cysteine-rich (CR) domain. Here, we provide in vivo evidence suggesting that dystrophin contains three additional membrane-binding domains including spectrin-like repeats (R)1-3, R10-12 and C-terminus (CT). To systematically study dystrophin membrane binding, we split full-length dystrophin into ten fragments and examined subcellular localizations of each fragment by adeno-associated virus-mediated gene transfer. In skeletal muscle, R1-3, CR domain and CT were exclusively localized at the sarcolemma. R10-12 showed both cytosolic and sarcolemmal localization. Importantly, the CR-independent membrane binding was conserved in murine and canine muscles. A critical function of the CR-mediated membrane interaction is the assembly of the dystrophin-associated glycoprotein complex (DGC). While R1-3 and R10-12 did not restore the DGC, surprisingly, CT alone was sufficient to establish the DGC at the sarcolemma. Additional studies suggest that R1-3 and CT also bind to the sarcolemma in the heart, though relatively weak. Taken together, our study provides the first conclusive in vivo evidence that dystrophin contains multiple independent membrane-binding domains. These structurally and functionally distinctive membrane-binding domains provide a molecular framework for dystrophin to function as a shock absorber and signaling hub. Our results not only shed critical light on dystrophin biology and DMD pathogenesis, but also provide a foundation for rationally engineering minimized dystrophins for DMD gene therapy.
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Affiliation(s)
- Junling Zhao
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Kasun Kodippili
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Chady H Hakim
- Department of Molecular Microbiology and Immunology, School of Medicine.,National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Lakmini Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Xiufang Pan
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Nora N Yang
- National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine .,Department of Neurology, School of Medicine.,Department of Bioengineering.,Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Yi Lai
- Department of Molecular Microbiology and Immunology, School of Medicine
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20
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Pipalia TG, Koth J, Roy SD, Hammond CL, Kawakami K, Hughes SM. Cellular dynamics of regeneration reveals role of two distinct Pax7 stem cell populations in larval zebrafish muscle repair. Dis Model Mech 2016; 9:671-84. [PMID: 27149989 PMCID: PMC4920144 DOI: 10.1242/dmm.022251] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 04/27/2016] [Indexed: 12/25/2022] Open
Abstract
Heterogeneity of stem cells or their niches is likely to influence tissue regeneration. Here we reveal stem/precursor cell diversity during wound repair in larval zebrafish somitic body muscle using time-lapse 3D confocal microscopy on reporter lines. Skeletal muscle with incision wounds rapidly regenerates both slow and fast muscle fibre types. A swift immune response is followed by an increase in cells at the wound site, many of which express the muscle stem cell marker Pax7. Pax7(+) cells proliferate and then undergo terminal differentiation involving Myogenin accumulation and subsequent loss of Pax7 followed by elongation and fusion to repair fast muscle fibres. Analysis of pax7a and pax7b transgenic reporter fish reveals that cells expressing each of the duplicated pax7 genes are distinctly localised in uninjured larvae. Cells marked by pax7a only or by both pax7a and pax7b enter the wound rapidly and contribute to muscle wound repair, but each behaves differently. Low numbers of pax7a-only cells form nascent fibres. Time-lapse microscopy revealed that the more numerous pax7b-marked cells frequently fuse to pre-existing fibres, contributing more strongly than pax7a-only cells to repair of damaged fibres. pax7b-marked cells are more often present in rows of aligned cells that are observed to fuse into a single fibre, but more rarely contribute to nascent regenerated fibres. Ablation of a substantial portion of nitroreductase-expressing pax7b cells with metronidazole prior to wounding triggered rapid pax7a-only cell accumulation, but this neither inhibited nor augmented pax7a-only cell-derived myogenesis and thus altered the cellular repair dynamics during wound healing. Moreover, pax7a-only cells did not regenerate pax7b cells, suggesting a lineage distinction. We propose a modified founder cell and fusion-competent cell model in which pax7a-only cells initiate fibre formation and pax7b cells contribute to fibre growth. This newly discovered cellular complexity in muscle wound repair raises the possibility that distinct populations of myogenic cells contribute differentially to repair in other vertebrates.
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Affiliation(s)
- Tapan G Pipalia
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Jana Koth
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 9DS, UK
| | - Shukolpa D Roy
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Christina L Hammond
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, and Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Simon M Hughes
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
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21
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Bajanca F, Gonzalez-Perez V, Gillespie SJ, Beley C, Garcia L, Theveneau E, Sear RP, Hughes SM. In vivo dynamics of skeletal muscle Dystrophin in zebrafish embryos revealed by improved FRAP analysis. eLife 2015; 4. [PMID: 26459831 PMCID: PMC4601390 DOI: 10.7554/elife.06541] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 09/10/2015] [Indexed: 12/30/2022] Open
Abstract
Dystrophin forms an essential link between sarcolemma and cytoskeleton, perturbation of which causes muscular dystrophy. We analysed Dystrophin binding dynamics in vivo for the first time. Within maturing fibres of host zebrafish embryos, our analysis reveals a pool of diffusible Dystrophin and complexes bound at the fibre membrane. Combining modelling, an improved FRAP methodology and direct semi-quantitative analysis of bleaching suggests the existence of two membrane-bound Dystrophin populations with widely differing bound lifetimes: a stable, tightly bound pool, and a dynamic bound pool with high turnover rate that exchanges with the cytoplasmic pool. The three populations were found consistently in human and zebrafish Dystrophins overexpressed in wild-type or dmd(ta222a/ta222a) zebrafish embryos, which lack Dystrophin, and in Gt(dmd-Citrine)(ct90a) that express endogenously-driven tagged zebrafish Dystrophin. These results lead to a new model for Dystrophin membrane association in developing muscle, and highlight our methodology as a valuable strategy for in vivo analysis of complex protein dynamics.
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Affiliation(s)
- Fernanda Bajanca
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,CNRS and Université Paul Sabatier, Toulouse, France
| | | | - Sean J Gillespie
- Department of Physics, University of Surrey, Guildford, United Kingdom
| | - Cyriaque Beley
- Université Versailles Saint-Quentin, Montigny-le-Bretonneux, France.,Laboratoire International Associé-Biologie appliquée aux handicaps neuromusculaires, Centre Scientifique de Monaco, Monaco, Monaco
| | - Luis Garcia
- Université Versailles Saint-Quentin, Montigny-le-Bretonneux, France.,Laboratoire International Associé-Biologie appliquée aux handicaps neuromusculaires, Centre Scientifique de Monaco, Monaco, Monaco
| | | | - Richard P Sear
- Department of Physics, University of Surrey, Guildford, United Kingdom
| | - Simon M Hughes
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
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