1
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Parry HA, Willingham TB, Giordano KA, Kim Y, Qazi S, Knutson JR, Combs CA, Glancy B. Impact of capillary and sarcolemmal proximity on mitochondrial structure and energetic function in skeletal muscle. J Physiol 2024; 602:1967-1986. [PMID: 38564214 PMCID: PMC11068488 DOI: 10.1113/jp286246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024] Open
Abstract
Mitochondria within skeletal muscle cells are located either between the muscle contractile apparatus (interfibrillar mitochondria, IFM) or beneath the cell membrane (subsarcolemmal mitochondria, SSM), with several structural and functional differences reported between IFM and SSM. However, recent 3D imaging studies demonstrate that mitochondria are particularly concentrated in the proximity of capillaries embedded in sarcolemmal grooves rather than in proximity to the sarcolemma itself (paravascular mitochondria, PVM). To evaluate the impact of capillary vs. sarcolemmal proximity, we compared the structure and function of skeletal muscle mitochondria located either lateral to embedded capillaries (PVM), adjacent to the sarcolemma but not in PVM pools (SSM) or interspersed between sarcomeres (IFM). Mitochondrial morphology and interactions were assessed by 3D electron microscopy coupled with machine learning segmentation, whereas mitochondrial energy conversion was assessed by two-photon microscopy of mitochondrial membrane potential, content, calcium, NADH redox and flux in live, intact cells. Structurally, although PVM and SSM were similarly larger than IFM, PVM were larger, rounder and had more physical connections to neighbouring mitochondria compared to both IFM and SSM. Functionally, PVM had similar or greater basal NADH flux compared to SSM and IFM, respectively, despite a more oxidized NADH pool and a greater membrane potential, signifying a greater activation of the electron transport chain in PVM. Together, these data indicate that proximity to capillaries has a greater impact on resting mitochondrial energy conversion and distribution in skeletal muscle than the sarcolemma alone. KEY POINTS: Capillaries have a greater impact on mitochondrial energy conversion in skeletal muscle than the sarcolemma. Paravascular mitochondria are larger, and the outer mitochondrial membrane is more connected with neighbouring mitochondria. Interfibrillar mitochondria are longer and have greater contact sites with other organelles (i.e. sarcoplasmic reticulum and lipid droplets). Paravascular mitochondria have greater activation of oxidative phosphorylation than interfibrillar mitochondria at rest, although this is not regulated by calcium.
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Affiliation(s)
- Hailey A. Parry
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - T. Bradley Willingham
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- Shephard Center’s Virginia C. Crawford Research Institute, Atlanta, GA, USA
| | | | - Yuho Kim
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- University of Massachusetts, Lowell, MA,USA
| | - Shureed Qazi
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jay R. Knutson
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Christian A. Combs
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brian Glancy
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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2
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Kim Y, Parry HA, Willingham TB, Alspaugh G, Lindberg E, Combs CA, Knutson JR, Bleck CKE, Glancy B. Reorganization of mitochondria-organelle interactions during postnatal development in skeletal muscle. J Physiol 2024; 602:891-912. [PMID: 38429930 PMCID: PMC10939894 DOI: 10.1113/jp285014] [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: 05/12/2023] [Accepted: 01/16/2024] [Indexed: 03/03/2024] Open
Abstract
Skeletal muscle cellular development requires the integrated assembly of mitochondria and other organelles adjacent to the sarcomere in support of muscle contractile performance. However, it remains unclear how interactions among organelles and with the sarcomere relates to the development of muscle cell function. Here, we combine 3D volume electron microscopy, proteomic analyses, and live cell functional imaging to investigate the postnatal reorganization of mitochondria-organelle interactions in skeletal muscle. We show that while mitochondrial networks are disorganized and loosely associated with the contractile apparatus at birth, contact sites among mitochondria, lipid droplets and the sarcoplasmic reticulum are highly abundant in neonatal muscles. The maturation process is characterized by a transition to highly organized mitochondrial networks wrapped tightly around the muscle sarcomere but also to less frequent interactions with both lipid droplets and the sarcoplasmic reticulum. Concomitantly, expression of proteins involved in mitochondria-organelle membrane contact sites decreases during postnatal development in tandem with a decrease in abundance of proteins associated with sarcomere assembly despite an overall increase in contractile protein abundance. Functionally, parallel measures of mitochondrial membrane potential, NADH redox status, and NADH flux within intact cells revealed that mitochondria in adult skeletal muscle fibres maintain a more activated electron transport chain compared with neonatal muscle mitochondria. These data demonstrate a developmental redesign reflecting a shift from muscle cell assembly and frequent inter-organelle communication toward a muscle fibre with mitochondrial structure, interactions, composition and function specialized to support contractile function. KEY POINTS: Mitochondrial network organization is remodelled during skeletal muscle postnatal development. The mitochondrial outer membrane is in frequent contact with other organelles at birth and transitions to more close associations with the contractile apparatus in mature muscles. Mitochondrial energy metabolism becomes more activated during postnatal development. Understanding the developmental redesign process within skeletal muscle cells may help pinpoint specific areas of deficit in muscles with developmental disorders.
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Affiliation(s)
- Yuho Kim
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
- Department of Physical Therapy and Kinesiology, University of Massachusetts Lowell, MA 01854, USA
| | - Hailey A. Parry
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - T. Bradley Willingham
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Greg Alspaugh
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Eric Lindberg
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Christian A. Combs
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Jay R. Knutson
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Christopher K. E. Bleck
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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3
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Yildiz B, Schiedt L, Mulaw M, Bockmann J, Jesse S, Lutz AK, Boeckers TM. Shank3 related muscular hypotonia is accompanied by increased intracellular calcium concentrations and ion channel dysregulation in striated muscle tissue. Front Cell Dev Biol 2023; 11:1243299. [PMID: 37745298 PMCID: PMC10511643 DOI: 10.3389/fcell.2023.1243299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Phelan-McDermid syndrome (PMS) is a syndromic form of Autism Spectrum Disorders (ASD) classified as a rare genetic neurodevelopmental disorder featuring global developmental delay, absent or delayed speech, ASD-like behaviour and neonatal skeletal muscle hypotonia. PMS is caused by a heterozygous deletion of the distal end of chromosome 22q13.3 or SHANK3 mutations. We analyzed striated muscles of newborn Shank3Δ11(-/-) animals and found a significant enlargement of the sarcoplasmic reticulum as previously seen in adult Shank3Δ11(-/-) mice, indicative of a Shank3-dependent and not compensatory mechanism for this structural alteration. We analyzed transcriptional differences by RNA-sequencing of muscle tissue of neonatal Shank3Δ11(-/-) mice and compared those to Shank3(+/+) controls. We found significant differences in gene expression of ion channels crucial for muscle contraction and for molecules involved in calcium ion regulation. In addition, calcium storage- [i.e., Calsequestrin (CSQ)], calcium secretion- and calcium-related signaling-proteins were found to be affected. By immunostainings and Western blot analyses we could confirm these findings both in Shank3Δ11(-/-) mice and PMS patient muscle tissue. Moreover, alterations could be induced in vitro by the selective downregulation of Shank3 in C2C12 myotubes. Our results emphasize that SHANK3 levels directly or indirectly regulate calcium homeostasis in a cell autonomous manner that might contribute to muscular hypotonia especially seen in the newborn.
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Affiliation(s)
- Berra Yildiz
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- International Graduate School in Molecular Medicine, IGradU, Ulm, Germany
| | - Lisa Schiedt
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- International Graduate School in Molecular Medicine, IGradU, Ulm, Germany
| | - Medhanie Mulaw
- Unit for Single-cell Genomics, Medical Faculty, Ulm University, Ulm, Germany
| | - Jürgen Bockmann
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Sarah Jesse
- Neurologie, Universitätsklinikum Ulm, Ulm, Germany
| | - Anne-Kathrin Lutz
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Tobias M. Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen, Ulm Site, Ulm, Germany
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4
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Pizza FX, Buckley KH. Regenerating Myofibers after an Acute Muscle Injury: What Do We Really Know about Them? Int J Mol Sci 2023; 24:12545. [PMID: 37628725 PMCID: PMC10454182 DOI: 10.3390/ijms241612545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Injury to skeletal muscle through trauma, physical activity, or disease initiates a process called muscle regeneration. When injured myofibers undergo necrosis, muscle regeneration gives rise to myofibers that have myonuclei in a central position, which contrasts the normal, peripheral position of myonuclei. Myofibers with central myonuclei are called regenerating myofibers and are the hallmark feature of muscle regeneration. An important and underappreciated aspect of muscle regeneration is the maturation of regenerating myofibers into a normal sized myofiber with peripheral myonuclei. Strikingly, very little is known about processes that govern regenerating myofiber maturation after muscle injury. As knowledge of myofiber formation and maturation during embryonic, fetal, and postnatal development has served as a foundation for understanding muscle regeneration, this narrative review discusses similarities and differences in myofiber maturation during muscle development and regeneration. Specifically, we compare and contrast myonuclear positioning, myonuclear accretion, myofiber hypertrophy, and myofiber morphology during muscle development and regeneration. We also discuss regenerating myofibers in the context of different types of myofiber necrosis (complete and segmental) after muscle trauma and injurious contractions. The overall goal of the review is to provide a framework for identifying cellular and molecular processes of myofiber maturation that are unique to muscle regeneration.
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Affiliation(s)
- Francis X. Pizza
- Department of Exercise and Rehabilitation Sciences, University of Toledo, Toledo, OH 43606, USA
| | - Kole H. Buckley
- Division of Gastroenterology and Hepatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA;
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5
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Murzilli S, Serano M, Pietrangelo L, Protasi F, Paolini C. Structural Adaptation of the Excitation-Contraction Coupling Apparatus in Calsequestrin1-Null Mice during Postnatal Development. BIOLOGY 2023; 12:1064. [PMID: 37626950 PMCID: PMC10452101 DOI: 10.3390/biology12081064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023]
Abstract
The precise arrangement and peculiar interaction of transverse tubule (T-tubule) and sarcoplasmic reticulum (SR) membranes efficiently guarantee adequate contractile properties of skeletal muscle fibers. Fast muscle fibers from mice lacking calsequestrin 1 (CASQ1) are characterized by the profound ultrastructural remodeling of T-tubule/SR junctions. This study investigates the role of CASQ1, an essential component of calcium release units (CRUs), in the postnatal development of muscle fibers. By using CASQ1-knockout mice, we examined the maturation of CRUs and the involvement of different junctional proteins in the juxtaposition of the membrane system. Our morphological investigation of both wild-type (WT) and CASQ1-null extensor digitorum longus (EDL) fibers, from 1 week to 4 months of age, yielded noteworthy findings. Firstly, we observed that the absence of CASQ1 hindered the full maturation of CRUs, despite the correct localization of key junctional components (ryanodine receptor, dihydropyridine receptor, and triadin) to the junctional SR in adult animals. Furthermore, analysis of protein expression profiles related to T-tubule biogenesis and organization (junctophilin 1, amphiphysin 2, caveolin 3, and mitsugumin 29) demonstrated delayed progression in their expression during postnatal development in the absence of CASQ1, suggesting the impaired maturation of CRUs. The absence of CASQ1 directly impacts the proper assembly of CRUs during development and influences the expression and coordination of other proteins involved in T-tubule biogenesis and organization.
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Affiliation(s)
- Stefania Murzilli
- Department of Neuroscience, Imaging and Clinical Sciences (DNISC), Center for Advanced Studies and Technology (CAST), University G. d’Annunzio of Chieti-Pescara, 66100 Chieti, Italy;
| | - Matteo Serano
- Department of Medicine and Aging Sciences (DMSI), Center for Advanced Studies and Technology (CAST), University G. d’Annunzio of Chieti-Pescara, 66100 Chieti, Italy; (M.S.); (L.P.); (F.P.)
| | - Laura Pietrangelo
- Department of Medicine and Aging Sciences (DMSI), Center for Advanced Studies and Technology (CAST), University G. d’Annunzio of Chieti-Pescara, 66100 Chieti, Italy; (M.S.); (L.P.); (F.P.)
| | - Feliciano Protasi
- Department of Medicine and Aging Sciences (DMSI), Center for Advanced Studies and Technology (CAST), University G. d’Annunzio of Chieti-Pescara, 66100 Chieti, Italy; (M.S.); (L.P.); (F.P.)
| | - Cecilia Paolini
- Department of Neuroscience, Imaging and Clinical Sciences (DNISC), Center for Advanced Studies and Technology (CAST), University G. d’Annunzio of Chieti-Pescara, 66100 Chieti, Italy;
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6
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Quinn CJ, Dibb KM. The origin of T-tubules. eLife 2023; 12:e88954. [PMID: 37339063 DOI: 10.7554/elife.88954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2023] Open
Abstract
Ring-like structures made up of caveolae appear to drive the development of membrane invaginations called T-tubules which are important for muscle contraction.
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Affiliation(s)
- Callum J Quinn
- Unit of Cardiac Physiology, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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7
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Szentesi P, Dienes B, Kutchukian C, Czirjak T, Buj-Bello A, Jacquemond V, Csernoch L. Disrupted T-tubular network accounts for asynchronous calcium release in MTM1-deficient skeletal muscle. J Physiol 2023; 601:99-121. [PMID: 36408764 PMCID: PMC10107287 DOI: 10.1113/jp283650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/14/2022] [Indexed: 11/22/2022] Open
Abstract
In mammalian skeletal muscle, the propagation of surface membrane depolarization into the interior of the muscle fibre along the transverse (T) tubular network is essential for the synchronized release of calcium from the sarcoplasmic reticulum (SR) via ryanodine receptors (RyRs) in response to the conformational change in the voltage-sensor dihydropyridine receptors. Deficiency in 3-phosphoinositide phosphatase myotubularin (MTM1) has been reported to disrupt T-tubules, resulting in impaired SR calcium release. Here confocal calcium transients recorded in muscle fibres of MTM1-deficient mice were compared with the results from a model where propagation of the depolarization along the T-tubules was modelled mathematically with disruptions in the network assumed to modify the access and transmembrane resistance as well as the capacitance. If, in simulations, T-tubules were assumed to be partially or completely inaccessible to the depolarization and RyRs at these points to be prime for calcium-induced calcium release, all the features of measured SR calcium release could be reproduced. We conclude that the inappropriate propagation of the depolarization into the fibre interior is the initial critical cause of severely impaired SR calcium release in MTM1 deficiency, while the Ca2+ -triggered opening of RyRs provides an alleviating support to the diseased process. KEY POINTS: Myotubular myopathy is a fatal disease due to genetic deficiency in the phosphoinositide phosphatase MTM1. Although the causes are known and corresponding gene therapy strategies are being developed, there is no mechanistic understanding of the disease-associated muscle function failure. Resolving this issue is of primary interest not only for a fundamental understanding of how MTM1 is critical for healthy muscle function, but also for establishing the related cellular mechanisms most primarily or stringently affected by the disease, which are thus of potential interest as therapy targets. The mathematical modelling approach used in the present work proves that the disease-associated alteration of the plasma membrane invagination network is sufficient to explain the dysfunctions of excitation-contraction coupling, providing the first integrated quantitative framework that explains the associated contraction failure.
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Affiliation(s)
- Peter Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Candice Kutchukian
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène, Lyon, France
| | - Tamas Czirjak
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ana Buj-Bello
- Genethon, Evry, France.,Université Paris-Saclay, Evry, France
| | - Vincent Jacquemond
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène, Lyon, France
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,ELRN-UD Cell Physiology Research Group, Debrecen, Hungary
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8
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Hinkle ER, Wiedner HJ, Torres EV, Jackson M, Black AJ, Blue RE, Harris SE, Guzman BB, Gentile GM, Lee EY, Tsai YH, Parker J, Dominguez D, Giudice J. Alternative splicing regulation of membrane trafficking genes during myogenesis. RNA (NEW YORK, N.Y.) 2022; 28:523-540. [PMID: 35082143 PMCID: PMC8925968 DOI: 10.1261/rna.078993.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Alternative splicing transitions occur during organ development, and, in numerous diseases, splicing programs revert to fetal isoform expression. We previously found that extensive splicing changes occur during postnatal mouse heart development in genes encoding proteins involved in vesicle-mediated trafficking. However, the regulatory mechanisms of this splicing-trafficking network are unknown. Here, we found that membrane trafficking genes are alternatively spliced in a tissue-specific manner, with striated muscles exhibiting the highest levels of alternative exon inclusion. Treatment of differentiated muscle cells with chromatin-modifying drugs altered exon inclusion in muscle cells. Examination of several RNA-binding proteins revealed that the poly-pyrimidine tract binding protein 1 (PTBP1) and quaking regulate splicing of trafficking genes during myogenesis, and that removal of PTBP1 motifs prevented PTBP1 from binding its RNA target. These findings enhance our understanding of developmental splicing regulation of membrane trafficking proteins which might have implications for muscle disease pathogenesis.
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Affiliation(s)
- Emma R Hinkle
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Hannah J Wiedner
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Eduardo V Torres
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Micaela Jackson
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Adam J Black
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - R Eric Blue
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Sarah E Harris
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Bryan B Guzman
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Gabrielle M Gentile
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Eunice Y Lee
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Yi-Hsuan Tsai
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Joel Parker
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Daniel Dominguez
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- McAllister Heart Institute, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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9
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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10
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Lo HP, Lim YW, Xiong Z, Martel N, Ferguson C, Ariotti N, Giacomotto J, Rae J, Floetenmeyer M, Moradi SV, Gao Y, Tillu VA, Xia D, Wang H, Rahnama S, Nixon SJ, Bastiani M, Day RD, Smith KA, Palpant NJ, Johnston WA, Alexandrov K, Collins BM, Hall TE, Parton RG. Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle. J Cell Biol 2021; 220:e201905065. [PMID: 34633413 PMCID: PMC8513623 DOI: 10.1083/jcb.201905065] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/02/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems, mouse and zebrafish. In both models, Cavin4 localized to T-tubules, and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.
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Affiliation(s)
- Harriet P. Lo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nick Martel
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jean Giacomotto
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, West Moreton Hospital and Health Service and University of Queensland, Brisbane, Queensland, Australia
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthias Floetenmeyer
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Shayli Varasteh Moradi
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Ya Gao
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Vikas A. Tillu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Di Xia
- Genome Innovation Hub, The University of Queensland, Brisbane, Queensland, Australia
| | - Huang Wang
- Translational Research Institute, Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Samira Rahnama
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Susan J. Nixon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Michele Bastiani
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ryan D. Day
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Kelly A. Smith
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nathan J. Palpant
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Wayne A. Johnston
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kirill Alexandrov
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Thomas E. Hall
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
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11
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Balderas-Villalobos J, Steele TWE, Eltit JM. Physiological and Pathological Relevance of Selective and Nonselective Ca 2+ Channels in Skeletal and Cardiac Muscle. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:225-247. [PMID: 35138617 PMCID: PMC10683374 DOI: 10.1007/978-981-16-4254-8_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Contraction of the striated muscle is fundamental for human existence. The action of voluntary skeletal muscle enables activities such as breathing, establishing body posture, and diverse body movements. Additionally, highly precise motion empowers communication, artistic expression, and other activities that define everyday human life. The involuntary contraction of striated muscle is the core function of the heart and is essential for blood flow. Several ion channels are important in the transduction of action potentials to cytosolic Ca2+ signals that enable muscle contraction; however, other ion channels are involved in the progression of muscle pathologies that can impair normal life or threaten it. This chapter describes types of selective and nonselective Ca2+ permeable ion channels expressed in the striated muscle, their participation in different aspects of muscle excitation and contraction, and their relevance to the progression of some pathological states.
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Affiliation(s)
- Jaime Balderas-Villalobos
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Tyler W E Steele
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Jose M Eltit
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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12
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Hall TE, Martel N, Ariotti N, Xiong Z, Lo HP, Ferguson C, Rae J, Lim YW, Parton RG. In vivo cell biological screening identifies an endocytic capture mechanism for T-tubule formation. Nat Commun 2020; 11:3711. [PMID: 32709891 PMCID: PMC7381618 DOI: 10.1038/s41467-020-17486-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 06/26/2020] [Indexed: 11/09/2022] Open
Abstract
The skeletal muscle T-tubule is a specialized membrane domain essential for coordinated muscle contraction. However, in the absence of genetically tractable systems the mechanisms involved in T-tubule formation are unknown. Here, we use the optically transparent and genetically tractable zebrafish system to probe T-tubule development in vivo. By combining live imaging of transgenic markers with three-dimensional electron microscopy, we derive a four-dimensional quantitative model for T-tubule formation. To elucidate the mechanisms involved in T-tubule formation in vivo, we develop a quantitative screen for proteins that associate with and modulate early T-tubule formation, including an overexpression screen of the entire zebrafish Rab protein family. We propose an endocytic capture model involving firstly, formation of dynamic endocytic tubules at transient nucleation sites on the sarcolemma, secondly, stabilization by myofibrils/sarcoplasmic reticulum and finally, delivery of membrane from the recycling endosome and Golgi complex.
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Affiliation(s)
- Thomas E Hall
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Nick Martel
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.,Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Kensington, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Harriet P Lo
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - James Rae
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia. .,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD, 4072, Australia.
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13
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Introducing a mammalian nerve-muscle preparation ideal for physiology and microscopy, the transverse auricular muscle in the ear of the mouse. Neuroscience 2019; 439:80-105. [PMID: 31351140 DOI: 10.1016/j.neuroscience.2019.07.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/10/2019] [Accepted: 07/15/2019] [Indexed: 11/23/2022]
Abstract
A new mammalian neuromuscular preparation is introduced for physiology and microscopy of all sorts: the intrinsic muscle of the mouse ear. The great utility of this preparation is demonstrated by illustrating how it has permitted us to develop a wholly new technique for staining muscle T-tubules, the critical conductive-elements in muscle. This involves sequential immersion in dilute solutions of osmium and ferrocyanide, then tannic acid, and then uranyl acetate, all of which totally blackens the T-tubules but leaves the muscle pale, thereby revealing that the T-tubules in mouse ear-muscles become severely distorted in several pathological conditions. These include certain mouse-models of muscular dystrophy (specifically, dysferlin-mutations), certain mutations of muscle cytoskeletal proteins (specifically, beta-tubulin mutations), and also in denervation-fibrillation, as observed in mouse ears maintained with in vitro tissue-culture conditions. These observations permit us to generate the hypothesis that T-tubules are the "Achilles' heel" in several adult-onset muscular dystrophies, due to their unique susceptibility to damage via muscle lattice-dislocations. These new observations strongly encourage further in-depth studies of ear-muscle architecture, in the many available mouse-models of various devastating human muscle-diseases. Finally, we demonstrate that the delicate and defined physical characteristics of this 'new' mammalian muscle are ideal for ultrastructural study, and thereby facilitate the imaging of synaptic vesicle membrane recycling in mammalian neuromuscular junctions, a topic that is critical to myasthenia gravis and related diseases, but which has, until now, completely eluded electron microscopic analysis. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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14
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Hinkle ER, Wiedner HJ, Black AJ, Giudice J. RNA processing in skeletal muscle biology and disease. Transcription 2019; 10:1-20. [PMID: 30556762 DOI: 10.1080/21541264.2018.1558677] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
RNA processing encompasses the capping, cleavage, polyadenylation and alternative splicing of pre-mRNA. Proper muscle development relies on precise RNA processing, driven by the coordination between RNA-binding proteins. Recently, skeletal muscle biology has been intensely investigated in terms of RNA processing. High throughput studies paired with deletion of RNA-binding proteins have provided a high-level understanding of the molecular mechanisms controlling the regulation of RNA-processing in skeletal muscle. Furthermore, misregulation of RNA processing is implicated in muscle diseases. In this review, we comprehensively summarize recent studies in skeletal muscle that demonstrated: (i) the importance of RNA processing, (ii) the RNA-binding proteins that are involved, and (iii) diseases associated with defects in RNA processing.
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Affiliation(s)
- Emma R Hinkle
- a Curriculum in Genetics and Molecular Biology (GMB) , University of North Carolina , Chapel Hill , USA.,b Department of Cell Biology & Physiology , University of North Carolina , Chapel Hill , USA
| | - Hannah J Wiedner
- a Curriculum in Genetics and Molecular Biology (GMB) , University of North Carolina , Chapel Hill , USA.,b Department of Cell Biology & Physiology , University of North Carolina , Chapel Hill , USA
| | - Adam J Black
- b Department of Cell Biology & Physiology , University of North Carolina , Chapel Hill , USA
| | - Jimena Giudice
- a Curriculum in Genetics and Molecular Biology (GMB) , University of North Carolina , Chapel Hill , USA.,b Department of Cell Biology & Physiology , University of North Carolina , Chapel Hill , USA.,c McAllister Heart Institute , University of North Carolina , Chapel Hill , USA
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15
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Roman W, Gomes ER. Nuclear positioning in skeletal muscle. Semin Cell Dev Biol 2018; 82:51-56. [DOI: 10.1016/j.semcdb.2017.11.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/24/2017] [Accepted: 11/06/2017] [Indexed: 01/01/2023]
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16
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Brinegar AE, Xia Z, Loehr JA, Li W, Rodney GG, Cooper TA. Extensive alternative splicing transitions during postnatal skeletal muscle development are required for calcium handling functions. eLife 2017; 6:27192. [PMID: 28826478 PMCID: PMC5577920 DOI: 10.7554/elife.27192] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 08/04/2017] [Indexed: 01/08/2023] Open
Abstract
Postnatal development of skeletal muscle is a highly dynamic period of tissue remodeling. Here, we used RNA-seq to identify transcriptome changes from late embryonic to adult mouse muscle and demonstrate that alternative splicing developmental transitions impact muscle physiology. The first 2 weeks after birth are particularly dynamic for differential gene expression and alternative splicing transitions, and calcium-handling functions are significantly enriched among genes that undergo alternative splicing. We focused on the postnatal splicing transitions of the three calcineurin A genes, calcium-dependent phosphatases that regulate multiple aspects of muscle biology. Redirected splicing of calcineurin A to the fetal isoforms in adult muscle and in differentiated C2C12 slows the timing of muscle relaxation, promotes nuclear localization of calcineurin target Nfatc3, and/or affects expression of Nfatc transcription targets. The results demonstrate a previously unknown specificity of calcineurin isoforms as well as the broader impact of alternative splicing during muscle postnatal development.
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Affiliation(s)
- Amy E Brinegar
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States.,Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States
| | - Zheng Xia
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States.,Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, United States
| | - James Anthony Loehr
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, United States
| | - Wei Li
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States.,Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, United States
| | - George Gerald Rodney
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, United States
| | - Thomas A Cooper
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States.,Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, United States
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17
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Valle G, Vergani B, Sacchetto R, Reggiani C, De Rosa E, Maccatrozzo L, Nori A, Villa A, Volpe P. Characterization of fast-twitch and slow-twitch skeletal muscles of calsequestrin 2 (CASQ2)-knock out mice: unexpected adaptive changes of fast-twitch muscles only. J Muscle Res Cell Motil 2017; 37:225-233. [PMID: 28130614 DOI: 10.1007/s10974-016-9463-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 12/22/2016] [Indexed: 01/02/2023]
Abstract
This study investigates the functional role of calsequestrin 2 (CASQ2) in both fast-twitch and slow-twitch skeletal muscles by using CASQ2-/- mice; CASQ2 is expressed throughout life in slow-twitch muscles, but only in the developmental and neonatal stages in fast-twitch muscles. CASQ2-/- causes increase in calsequestrin 1 (CASQ1) expression, but without functional changes in both muscle types. CASQ2-/- mice have ultrastructural changes in fast-twitch muscles only, i.e., formation of pentads and stacks in the sarcoplasmic reticulum.
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Affiliation(s)
- Giorgia Valle
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Barbara Vergani
- Consorzio MIA (Microscopy Image Analysis), Università di Milano-Bicocca, 20052, Monza, Italy
| | - Roberta Sacchetto
- Dipartimento di Biomedicina Comparata ed Alimentazione dell'Università di Padova, Padova, Italy
| | - Carlo Reggiani
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Edith De Rosa
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Lisa Maccatrozzo
- Dipartimento di Biomedicina Comparata ed Alimentazione dell'Università di Padova, Padova, Italy
| | - Alessandra Nori
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Antonello Villa
- Consorzio MIA (Microscopy Image Analysis), Università di Milano-Bicocca, 20052, Monza, Italy
| | - Pompeo Volpe
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy.
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18
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Hofhuis J, Bersch K, Büssenschütt R, Drzymalski M, Liebetanz D, Nikolaev VO, Wagner S, Maier LS, Gärtner J, Klinge L, Thoms S. Dysferlin mediates membrane tubulation and links T-tubule biogenesis to muscular dystrophy. J Cell Sci 2017; 130:841-852. [PMID: 28104817 DOI: 10.1242/jcs.198861] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/28/2016] [Indexed: 12/30/2022] Open
Abstract
The multi-C2 domain protein dysferlin localizes to the plasma membrane and the T-tubule system in skeletal muscle; however, its physiological mode of action is unknown. Mutations in the DYSF gene lead to autosomal recessive limb-girdle muscular dystrophy type 2B and Miyoshi myopathy. Here, we show that dysferlin has membrane tubulating capacity and that it shapes the T-tubule system. Dysferlin tubulates liposomes, generates a T-tubule-like membrane system in non-muscle cells, and links the recruitment of phosphatidylinositol 4,5-bisphosphate to the biogenesis of the T-tubule system. Pathogenic mutant forms interfere with all of these functions, indicating that muscular wasting and dystrophy are caused by the dysferlin mutants' inability to form a functional T-tubule membrane system.
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Affiliation(s)
- Julia Hofhuis
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Kristina Bersch
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Ronja Büssenschütt
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Marzena Drzymalski
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - David Liebetanz
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Viacheslav O Nikolaev
- Department of Cardiology and Pneumology, Heart Research Centre Göttingen, Göttingen 37075, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Centre Regensburg, Regensburg 93042, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Centre Regensburg, Regensburg 93042, Germany
| | - Jutta Gärtner
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Lars Klinge
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
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19
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Caprara GA, Morabito C, Perni S, Navarra R, Guarnieri S, Mariggiò MA. Evidence for Altered Ca 2+ Handling in Growth Associated Protein 43-Knockout Skeletal Muscle. Front Physiol 2016; 7:493. [PMID: 27833566 PMCID: PMC5080375 DOI: 10.3389/fphys.2016.00493] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
Neuronal growth-associated protein 43 (GAP43) has crucial roles in the nervous system, and during development, regeneration after injury, and learning and memory. GAP43 is expressed in mouse skeletal muscle fibers and satellite cells, with suggested its involvement in intracellular Ca2+ handling. However, the physiological role of GAP43 in muscle remains unknown. Using a GAP43-knockout (GAP43-/-) mouse, we have defined the role of GAP43 in skeletal muscle. GAP43-/- mice showed low survival beyond weaning, reduced adult body weight, decreased muscle strength, and changed myofiber ultrastructure, with no significant differences in the expression of markers of satellite cell and myotube progression through the myogenic program. Thus, GAP43 expression is involved in timing of muscle maturation in-vivo. Intracellular Ca2+ measurements in-vitro in myotubes revealed GAP43 involvement in Ca2+ handling. In the absence of GAP43 expression, the spontaneous Ca2+ variations had greater amplitudes and higher frequency. In GAP43-/- myotubes, also the intracellular Ca2+ variations induced by the activation of dihydropyridine and ryanodine Ca2+ channels, resulted modified. These evidences suggested dysregulation of Ca2+ homeostasis. The emerging hypothesis indicates that GAP43 interacts with calmodulin to indirectly modulate the activities of dihydropyridine and ryanodine Ca2+ channels. This thus influences intracellular Ca2+ dynamics and its related intracellular patterns, from functional excitation-contraction coupling, to cell metabolism, and gene expression.
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Affiliation(s)
- Giusy A Caprara
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Caterina Morabito
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Stefano Perni
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Riccardo Navarra
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Simone Guarnieri
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Maria A Mariggiò
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
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20
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Organization of junctional sarcoplasmic reticulum proteins in skeletal muscle fibers. J Muscle Res Cell Motil 2015; 36:501-15. [DOI: 10.1007/s10974-015-9421-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/08/2015] [Indexed: 01/24/2023]
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21
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Pinali C, Kitmitto A. Serial block face scanning electron microscopy for the study of cardiac muscle ultrastructure at nanoscale resolutions. J Mol Cell Cardiol 2014; 76:1-11. [PMID: 25149127 DOI: 10.1016/j.yjmcc.2014.08.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/31/2014] [Accepted: 08/12/2014] [Indexed: 12/28/2022]
Abstract
Electron microscopy techniques have made a significant contribution towards understanding muscle physiology since the 1950s. Subsequent advances in hardware and software have led to major breakthroughs in terms of image resolution as well as the ability to generate three-dimensional (3D) data essential for linking structure to function and dysfunction. In this methodological review we consider the application of a relatively new technique, serial block face scanning electron microscopy (SBF-SEM), for the study of cardiac muscle morphology. Employing SBF-SEM we have generated 3D data for cardiac myocytes within the myocardium with a voxel size of ~15 nm in the X-Y plane and 50 nm in the Z-direction. We describe how SBF-SEM can be used in conjunction with selective staining techniques to reveal the 3D cellular organisation and the relationship between the t-tubule (t-t) and sarcoplasmic reticulum (SR) networks. These methods describe how SBF-SEM can be used to provide qualitative data to investigate the organisation of the dyad, a specialised calcium microdomain formed between the t-ts and the junctional portion of the SR (jSR). We further describe how image analysis methods may be applied to interrogate the 3D volumes to provide quantitative data such as the volume of the cell occupied by the t-t and SR membranes and the volumes and surface area of jSR patches. We consider the strengths and weaknesses of the SBF-SEM technique, pitfalls in sample preparation together with tips and methods for image analysis. By providing a 'big picture' view at high resolutions, in comparison to conventional confocal microscopy, SBF-SEM represents a paradigm shift for imaging cellular networks in their native environment.
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Affiliation(s)
- Christian Pinali
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, University of Manchester, M13 9NT, UK
| | - Ashraf Kitmitto
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, University of Manchester, M13 9NT, UK.
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22
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Lee CS, Georgiou DK, Dagnino-Acosta A, Xu J, Ismailov II, Knoblauch M, Monroe TO, Ji R, Hanna AD, Joshi AD, Long C, Oakes J, Tran T, Corona BT, Lorca S, Ingalls CP, Narkar VA, Lanner JT, Bayle JH, Durham WJ, Hamilton SL. Ligands for FKBP12 increase Ca2+ influx and protein synthesis to improve skeletal muscle function. J Biol Chem 2014; 289:25556-70. [PMID: 25053409 DOI: 10.1074/jbc.m114.586289] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Rapamycin at high doses (2-10 mg/kg body weight) inhibits mammalian target of rapamycin complex 1 (mTORC1) and protein synthesis in mice. In contrast, low doses of rapamycin (10 μg/kg) increase mTORC1 activity and protein synthesis in skeletal muscle. Similar changes are found with SLF (synthetic ligand for FKBP12, which does not inhibit mTORC1) and in mice with a skeletal muscle-specific FKBP12 deficiency. These interventions also increase Ca(2+) influx to enhance refilling of sarcoplasmic reticulum Ca(2+) stores, slow muscle fatigue, and increase running endurance without negatively impacting cardiac function. FKBP12 deficiency or longer treatments with low dose rapamycin or SLF increase the percentage of type I fibers, further adding to fatigue resistance. We demonstrate that FKBP12 and its ligands impact multiple aspects of muscle function.
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Affiliation(s)
- Chang Seok Lee
- From the Baylor College of Medicine, Houston, Texas 77030
| | | | | | - Jianjun Xu
- From the Baylor College of Medicine, Houston, Texas 77030
| | | | - Mark Knoblauch
- From the Baylor College of Medicine, Houston, Texas 77030
| | | | - RuiRui Ji
- From the Baylor College of Medicine, Houston, Texas 77030
| | - Amy D Hanna
- From the Baylor College of Medicine, Houston, Texas 77030
| | - Aditya D Joshi
- From the Baylor College of Medicine, Houston, Texas 77030
| | - Cheng Long
- From the Baylor College of Medicine, Houston, Texas 77030
| | - Joshua Oakes
- From the Baylor College of Medicine, Houston, Texas 77030
| | - Ted Tran
- From the Baylor College of Medicine, Houston, Texas 77030
| | - Benjamin T Corona
- the Muscle Biology Laboratory, Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia 30302
| | - Sabina Lorca
- the Center for Metabolic and Degenerative Disease, University of Texas Health Science Center, Houston, Texas 77030, and
| | - Christopher P Ingalls
- the Muscle Biology Laboratory, Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia 30302
| | - Vihang A Narkar
- the Center for Metabolic and Degenerative Disease, University of Texas Health Science Center, Houston, Texas 77030, and
| | | | - J Henri Bayle
- From the Baylor College of Medicine, Houston, Texas 77030
| | - William J Durham
- the Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-1041
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23
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Hong T, Yang H, Zhang SS, Cho HC, Kalashnikova M, Sun B, Zhang H, Bhargava A, Grabe M, Olgin J, Gorelik J, Marbán E, Jan LY, Shaw RM. Cardiac BIN1 folds T-tubule membrane, controlling ion flux and limiting arrhythmia. Nat Med 2014; 20:624-32. [PMID: 24836577 PMCID: PMC4048325 DOI: 10.1038/nm.3543] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/24/2014] [Indexed: 11/08/2022]
Abstract
Cardiomyocyte T tubules are important for regulating ion flux. Bridging integrator 1 (BIN1) is a T-tubule protein associated with calcium channel trafficking that is downregulated in failing hearts. Here we find that cardiac T tubules normally contain dense protective inner membrane folds that are formed by a cardiac isoform of BIN1. In mice with cardiac Bin1 deletion, T-tubule folding is decreased, which does not change overall cardiomyocyte morphology but leads to free diffusion of local extracellular calcium and potassium ions, prolonging action-potential duration and increasing susceptibility to ventricular arrhythmias. We also found that T-tubule inner folds are rescued by expression of the BIN1 isoform BIN1+13+17, which promotes N-WASP-dependent actin polymerization to stabilize the T-tubule membrane at cardiac Z discs. BIN1+13+17 recruits actin to fold the T-tubule membrane, creating a 'fuzzy space' that protectively restricts ion flux. When the amount of the BIN1+13+17 isoform is decreased, as occurs in acquired cardiomyopathy, T-tubule morphology is altered, and arrhythmia can result.
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Affiliation(s)
- TingTing Hong
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Huanghe Yang
- Departments of Physiology, Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Shan-Shan Zhang
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Hee Cheol Cho
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Mariya Kalashnikova
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Baiming Sun
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Hao Zhang
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Anamika Bhargava
- Imperial Center for Translational and Experimental Medicine, Imperial College, London, UK
| | - Michael Grabe
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Jeffrey Olgin
- Division of Cardiology, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Julia Gorelik
- Imperial Center for Translational and Experimental Medicine, Imperial College, London, UK
| | - Eduardo Marbán
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lily Y. Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, USA
| | - Robin M. Shaw
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Distinct regions of triadin are required for targeting and retention at the junctional domain of the sarcoplasmic reticulum. Biochem J 2014; 458:407-17. [DOI: 10.1042/bj20130719] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Three regions contribute to triadin localization to the junctional sarcoplasmic reticulum. Dynamics studies revealed that TR3 mediates triadin stability at junctional sites. The stable association of triadin at the junctional sites is facilitated by interactions with calsequestrin-1.
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Ferrantini C, Crocini C, Coppini R, Vanzi F, Tesi C, Cerbai E, Poggesi C, Pavone FS, Sacconi L. The transverse-axial tubular system of cardiomyocytes. Cell Mol Life Sci 2013; 70:4695-710. [PMID: 23846763 PMCID: PMC11113601 DOI: 10.1007/s00018-013-1410-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/03/2013] [Accepted: 06/13/2013] [Indexed: 10/26/2022]
Abstract
A characteristic histological feature of striated muscle cells is the presence of deep invaginations of the plasma membrane (sarcolemma), most commonly referred to as T-tubules or the transverse-axial tubular system (TATS). TATS mediates the rapid spread of the electrical signal (action potential) to the cell core triggering Ca(2+) release from the sarcoplasmic reticulum, ultimately inducing myofilament contraction (excitation-contraction coupling). T-tubules, first described in vertebrate skeletal muscle cells, have also been recognized for a long time in mammalian cardiac ventricular myocytes, with a structure and a function that in recent years have been shown to be far more complex and pivotal for cardiac function than initially thought. Renewed interest in T-tubule function stems from the loss and disorganization of T-tubules found in a number of pathological conditions including human heart failure (HF) and dilated and hypertrophic cardiomyopathies, as well as in animal models of HF, chronic ischemia and atrial fibrillation. Disease-related remodeling of the TATS leads to asynchronous and inhomogeneous Ca(2+)-release, due to the presence of orphan ryanodine receptors that have lost their coupling with the dihydropyridine receptors and are either not activated or activated with a delay. Here, we review the physiology of the TATS, focusing first on the relationship between function and structure, and then describing T-tubular remodeling and its reversal in disease settings and following effective therapeutic approaches.
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Affiliation(s)
- C. Ferrantini
- Division of Physiology, Department of Clinical and Experimental Medicine, University of Florence, Florence, Italy
- Centre of Molecular Medicine (C.I.M.M.B.A.), University of Florence, Florence, Italy
| | - C. Crocini
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy
| | - R. Coppini
- Centre of Molecular Medicine (C.I.M.M.B.A.), University of Florence, Florence, Italy
- Division of Pharmacology, Department “NeuroFarBa”, University of Florence, Florence, Italy
| | - F. Vanzi
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy
- Department of Biology, University of Florence, Florence, Italy
| | - C. Tesi
- Division of Physiology, Department of Clinical and Experimental Medicine, University of Florence, Florence, Italy
- Centre of Molecular Medicine (C.I.M.M.B.A.), University of Florence, Florence, Italy
| | - E. Cerbai
- Centre of Molecular Medicine (C.I.M.M.B.A.), University of Florence, Florence, Italy
- Division of Pharmacology, Department “NeuroFarBa”, University of Florence, Florence, Italy
| | - C. Poggesi
- Division of Physiology, Department of Clinical and Experimental Medicine, University of Florence, Florence, Italy
- Centre of Molecular Medicine (C.I.M.M.B.A.), University of Florence, Florence, Italy
| | - F. S. Pavone
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy
- Department of Physics and Astronomy, University of Florence, Sesto Fiorentino, Italy
- National Institute of Optics (INO), National Research Council (CNR), Florence, Italy
| | - L. Sacconi
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy
- National Institute of Optics (INO), National Research Council (CNR), Florence, Italy
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26
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Amoasii L, Hnia K, Chicanne G, Brech A, Cowling BS, Müller MM, Schwab Y, Koebel P, Ferry A, Payrastre B, Laporte J. Myotubularin and PtdIns3P remodel the sarcoplasmic reticulum in muscle in vivo. J Cell Sci 2013; 126:1806-19. [PMID: 23444364 DOI: 10.1242/jcs.118505] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The sarcoplasmic reticulum (SR) is a specialized form of endoplasmic reticulum (ER) in skeletal muscle and is essential for calcium homeostasis. The mechanisms involved in SR remodeling and maintenance of SR subdomains are elusive. In this study, we identified myotubularin (MTM1), a phosphoinositide phosphatase mutated in X-linked centronuclear myopathy (XLCNM, or myotubular myopathy), as a key regulator of phosphatidylinositol 3-monophosphate (PtdIns3P) levels at the SR. MTM1 is predominantly located at the SR cisternae of the muscle triads, and Mtm1-deficient mouse muscles and myoblasts from XLCNM patients exhibit abnormal SR/ER networks. In vivo modulation of MTM1 enzymatic activity in skeletal muscle using ectopic expression of wild-type or a dead-phosphatase MTM1 protein leads to differential SR remodeling. Active MTM1 is associated with flat membrane stacks, whereas dead-phosphatase MTM1 mutant promotes highly curved cubic membranes originating from the SR and enriched in PtdIns3P. Overexpression of a tandem FYVE domain with high affinity for PtdIns3P alters the shape of the SR cisternae at the triad. Our findings, supported by the parallel analysis of the Mtm1-null mouse and an in vivo study, reveal a direct function of MTM1 enzymatic activity in SR remodeling and a key role for PtdIns3P in promoting SR membrane curvature in skeletal muscle. We propose that alteration in SR remodeling is a primary cause of X-linked centronuclear myopathy. The tight regulation of PtdIns3P on specific membrane subdomains may be a general mechanism to control membrane curvature.
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Affiliation(s)
- Leonela Amoasii
- Department of Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Collège de France, 67404 Illkirch, France
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27
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Voigt T, Sebald HJ, Schoenauer R, Levano S, Girard T, Hoppeler HH, Babiychuk EB, Draeger A. Annexin A1 is a biomarker of T-tubular repair in skeletal muscle of nonmyopathic patients undergoing statin therapy. FASEB J 2013; 27:2156-64. [PMID: 23413360 DOI: 10.1096/fj.12-219345] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Skeletal muscle complaints are a common consequence of cholesterol-lowering therapy. Transverse tubular (T-tubular) vacuolations occur in patients having statin-associated myopathy and, to a lesser extent, in statin-treated patients without myopathy. We have investigated quantitative changes in T-tubular morphology and looked for early indicators of T-tubular membrane repair in skeletal muscle biopsy samples from patients receiving cholesterol-lowering therapy who do not have myopathic side effects. Gene expression and protein levels of incipient membrane repair proteins were monitored in patients who tolerated statin treatment without myopathy and in statin-naive subjects. In addition, morphometry of the T-tubular system was performed. Only the gene expression for annexin A1 was up-regulated, whereas the expression of other repair genes remained unchanged. However, annexin A1 and dysferlin protein levels were significantly increased. In statin-treated patients, the volume fraction of the T-tubular system was significantly increased, but the volume fraction of the sarcoplasmic reticulum remained unchanged. A complex surface structure in combination with high mechanical loads makes skeletal muscle plasma membranes susceptible to injury. Ca(2+)-dependent membrane repair proteins such as dysferlin and annexin A1 are deployed at T-tubular sites. The up-regulation of annexin A1 gene expression and protein points to this protein as a biomarker for T-tubular repair.
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Affiliation(s)
- Tilman Voigt
- Institute of Anatomy, Inselspital, University of Bern, Bern, Switzerland
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28
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DiFranco M, Yu C, Quiñonez M, Vergara JL. Age-dependent chloride channel expression in skeletal muscle fibres of normal and HSA(LR) myotonic mice. J Physiol 2012; 591:1347-71. [PMID: 23247112 DOI: 10.1113/jphysiol.2012.246546] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Abstract We combine electrophysiological and optical techniques to investigate the role that the expression of chloride channels (ClC-1) plays on the age-dependent electrical properties of mammalian muscle fibres. To this end, we comparatively evaluate the magnitude and voltage dependence of chloride currents (ICl), as well as the resting resistance, in fibres isolated from control and human skeletal actin (HSA)(LR) mice (a model of myotonic dystrophy) of various ages. In control mice, the maximal peak chloride current ([peak-ICl]max) increases from -583 ± 126 to -956 ± 260 μA cm(-2) (mean ± SD) between 3 and 6 weeks old. Instead, in 3-week-old HSA(LR) mice, ICl are significantly smaller (-153 ± 33 μA cm(-2)) than in control mice, but after a long period of ∼14 weeks they reach statistically comparable values. Thus, the severe ClC-1 channelopathy in young HSA(LR) animals is slowly reversed with aging. Frequency histograms of the maximal chloride conductance (gCl,max) in fibres of young HSA(LR) animals are narrow and centred in low values; alternatively, those from older animals show broad distributions, centred at larger gCl,max values, compatible with mosaic expressions of ClC-1 channels. In fibres of both animal strains, optical data confirm the age-dependent increase in gCl, and additionally suggest that ClC-1 channels are evenly distributed between the sarcolemma and transverse tubular system membranes. Although gCl is significantly depressed in fibres of young HSA(LR) mice, the resting membrane resistance (Rm) at -90 mV is only slightly larger than in control mice due to upregulation of a Rb-sensitive resting conductance (gK,IR). In adult animals, differences in Rm are negligible between fibres of both strains, and the contributions of gCl and gK,IR are less altered in HSA(LR) animals. We surmise that while hyperexcitability in young HSA(LR) mice can be readily explained on the basis of reduced gCl, myotonia in adult HSA(LR) animals may be explained on the basis of a mosaic expression of ClC-1 channels in different fibres and/or on alterations of other conductances.
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Affiliation(s)
- Marino DiFranco
- Department of Physiology, David Geffen School of Medicine, UCLA, USA
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29
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Ryanodine Receptor Physiology and Its Role in Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:217-34. [DOI: 10.1007/978-94-007-2888-2_9] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Al-Qusairi L, Laporte J. T-tubule biogenesis and triad formation in skeletal muscle and implication in human diseases. Skelet Muscle 2011; 1:26. [PMID: 21797990 PMCID: PMC3156648 DOI: 10.1186/2044-5040-1-26] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 07/13/2011] [Indexed: 12/25/2022] Open
Abstract
In skeletal muscle, the excitation-contraction (EC) coupling machinery mediates the translation of the action potential transmitted by the nerve into intracellular calcium release and muscle contraction. EC coupling requires a highly specialized membranous structure, the triad, composed of a central T-tubule surrounded by two terminal cisternae from the sarcoplasmic reticulum. While several proteins located on these structures have been identified, mechanisms governing T-tubule biogenesis and triad formation remain largely unknown. Here, we provide a description of triad structure and plasticity and review the role of proteins that have been linked to T-tubule biogenesis and triad formation and/or maintenance specifically in skeletal muscle: caveolin 3, amphiphysin 2, dysferlin, mitsugumins, junctophilins, myotubularin, ryanodine receptor, and dihydhropyridine Receptor. The importance of these proteins in triad biogenesis and subsequently in muscle contraction is sustained by studies on animal models and by the direct implication of most of these proteins in human myopathies.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Translational Medecine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), 1 rue Laurent Fries, 67404 Illkirch, France.
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31
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Barthélémy F, Wein N, Krahn M, Lévy N, Bartoli M. Translational research and therapeutic perspectives in dysferlinopathies. Mol Med 2011; 17:875-82. [PMID: 21556485 DOI: 10.2119/molmed.2011.00084] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 05/05/2011] [Indexed: 12/13/2022] Open
Abstract
Dysferlinopathies are autosomal recessive disorders caused by mutations in the dysferlin (DYSF) gene, encoding the dysferlin protein. DYSF mutations lead to a wide range of muscular phenotypes, with the most prominent being Miyoshi myopathy (MM) and limb girdle muscular dystrophy type 2B (LGMD2B) and the second most common being LGMD. Symptoms generally appear at the end of childhood and, although disease progression is typically slow, walking impairments eventually result. Dysferlin is a modular type II transmembrane protein for which numerous binding partners have been identified. Although dysferlin function is only partially elucidated, this large protein contains seven calcium sensor C2 domains, shown to play a key role in muscle membrane repair. On the basis of this major function, along with detailed clinical observations, it has been possible to design various therapeutic approaches for dysferlin-deficient patients. Among them, exon-skipping and minigene transfer strategies have been evaluated at the preclinical level and, to date, represent promising approaches for clinical trials. This review aims to summarize the pathophysiology of dysferlinopathies and to evaluate the therapeutic potential for treatments currently under development.
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Affiliation(s)
- Florian Barthélémy
- University of the Mediterranean, Marseille Medical School, Marseille, France Inserm UMR_S 910 Medical Genetics and Functional Genomics Marseille, France
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32
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Grounds MD, Shavlakadze T. Growing muscle has different sarcolemmal properties from adult muscle: A proposal with scientific and clinical implications. Bioessays 2011; 33:458-68. [DOI: 10.1002/bies.201000136] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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33
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Couchoux H, Bichraoui H, Chouabe C, Altafaj X, Bonvallet R, Allard B, Ronjat M, Berthier C. Caveolin-3 is a direct molecular partner of the Cav1.1 subunit of the skeletal muscle L-type calcium channel. Int J Biochem Cell Biol 2011; 43:713-20. [PMID: 21262376 DOI: 10.1016/j.biocel.2011.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/18/2010] [Accepted: 01/17/2011] [Indexed: 12/14/2022]
Abstract
Caveolin-3 is the striated muscle specific isoform of the scaffolding protein family of caveolins and has been shown to interact with a variety of proteins, including ion channels. Mutations in the human CAV3 gene have been associated with several muscle disorders called caveolinopathies and among these, the P104L mutation (Cav-3(P104L)) leads to limb girdle muscular dystrophy of type 1C characterized by the loss of sarcolemmal caveolin. There is still no clear-cut explanation as to specifically how caveolin-3 mutations lead to skeletal muscle wasting. Previous results argued in favor of a role for caveolin-3 in dihydropyridine receptor (DHPR) functional regulation and/or T-tubular membrane localization. It appeared worth closely examining such a functional link and investigating if it could result from the direct physical interaction of the two proteins. Transient expression of Cav-3(P104L) or caveolin-3 specific siRNAs in C2C12 myotubes both led to a significant decrease of the L-type Ca(2+) channel maximal conductance. Immunolabeling analysis of adult skeletal muscle fibers revealed the colocalization of a pool of caveolin-3 with the DHPR within the T-tubular membrane. Caveolin-3 was also shown to be present in DHPR-containing triadic membrane preparations from which both proteins co-immunoprecipitated. Using GST-fusion proteins, the I-II loop of Ca(v)1.1 was identified as the domain interacting with caveolin-3, with an apparent affinity of 60nM. The present study thus revealed a direct molecular interaction between caveolin-3 and the DHPR which is likely to underlie their functional link and whose loss might therefore be involved in pathophysiological mechanisms associated to muscle caveolinopathies.
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Affiliation(s)
- Harold Couchoux
- Physiologie Intégrative Cellulaire et Moléculaire, Université Lyon 1, UMR CNRS 5123, Université de Lyon, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne, France
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34
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Lueck JD, Rossi AE, Thornton CA, Campbell KP, Dirksen RT. Sarcolemmal-restricted localization of functional ClC-1 channels in mouse skeletal muscle. J Gen Physiol 2010; 136:597-613. [PMID: 21078869 PMCID: PMC2995150 DOI: 10.1085/jgp.201010526] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 10/26/2010] [Indexed: 02/01/2023] Open
Abstract
Skeletal muscle fibers exhibit a high resting chloride conductance primarily determined by ClC-1 chloride channels that stabilize the resting membrane potential during repetitive stimulation. Although the importance of ClC-1 channel activity in maintaining normal muscle excitability is well appreciated, the subcellular location of this conductance remains highly controversial. Using a three-pronged multidisciplinary approach, we determined the location of functional ClC-1 channels in adult mouse skeletal muscle. First, formamide-induced detubulation of single flexor digitorum brevis (FDB) muscle fibers from 15-16-day-old mice did not significantly alter macroscopic ClC-1 current magnitude (at -140 mV; -39.0 +/- 4.5 and -42.3 +/- 5.0 nA, respectively), deactivation kinetics, or voltage dependence of channel activation (V(1/2) was -61.0 +/- 1.7 and -64.5 +/- 2.8 mV; k was 20.5 ± 0.8 and 22.8 +/- 1.2 mV, respectively), despite a 33% reduction in cell capacitance (from 465 +/- 36 to 312 +/- 23 pF). In paired whole cell voltage clamp experiments, where ClC-1 activity was measured before and after detubulation in the same fiber, no reduction in ClC-1 activity was observed, despite an approximately 40 and 60% reduction in membrane capacitance in FDB fibers from 15-16-day-old and adult mice, respectively. Second, using immunofluorescence and confocal microscopy, native ClC-1 channels in adult mouse FDB fibers were localized within the sarcolemma, 90 degrees out of phase with double rows of dihydropyridine receptor immunostaining of the T-tubule system. Third, adenoviral-mediated expression of green fluorescent protein-tagged ClC-1 channels in adult skeletal muscle of a mouse model of myotonic dystrophy type 1 resulted in a significant reduction in myotonia and localization of channels to the sarcolemma. Collectively, these results demonstrate that the majority of functional ClC-1 channels localize to the sarcolemma and provide essential insight into the basis of myofiber excitability in normal and diseased skeletal muscle.
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Affiliation(s)
- John D. Lueck
- Department of Pharmacology and Physiology, and Department of Neurology, University of Rochester, Rochester, NY 14642
- Department of Molecular Physiology and Biophysics, Department of Internal Medicine, Department of Neurology, and Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52246
| | - Ann E. Rossi
- Department of Pharmacology and Physiology, and Department of Neurology, University of Rochester, Rochester, NY 14642
| | - Charles A. Thornton
- Department of Pharmacology and Physiology, and Department of Neurology, University of Rochester, Rochester, NY 14642
| | - Kevin P. Campbell
- Department of Molecular Physiology and Biophysics, Department of Internal Medicine, Department of Neurology, and Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52246
| | - Robert T. Dirksen
- Department of Pharmacology and Physiology, and Department of Neurology, University of Rochester, Rochester, NY 14642
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Sadikot T, Hammond CR, Ferrari MB. Distinct roles for telethonin N-versus C-terminus in sarcomere assembly and maintenance. Dev Dyn 2010; 239:1124-35. [PMID: 20235223 DOI: 10.1002/dvdy.22263] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The N-terminus of telethonin forms a unique structure linking two titin N-termini at the Z-disc. While a specific role for the C-terminus has not been established, several studies indicate it may have a regulatory function. Using a morpholino approach in Xenopus, we show that telethonin knockdown leads to embryonic paralysis, myocyte defects, and sarcomeric disruption. These myopathic defects can be rescued by expressing full-length telethonin mRNA in morpholino background, indicating that telethonin is required for myofibrillogenesis. However, a construct missing C-terminal residues is incapable of rescuing motility or sarcomere assembly in cultured myocytes. We, therefore, tested two additional constructs: one where four C-terminal phosphorylatable residues were mutated to alanines and another where terminal residues were randomly replaced. Data from these experiments support that the telethonin C-terminus is required for assembly, but in a context-dependent manner, indicating that factors and forces present in vivo can compensate for C-terminal truncation or mutation.
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Affiliation(s)
- Takrima Sadikot
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri, Kansas City, Missouri 64110, USA
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36
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Tomori K, Ohta Y, Nishizawa T, Tamaki H, Takekura H. Low-intensity electrical stimulation ameliorates disruption of transverse tubules and neuromuscular junctional architecture in denervated rat skeletal muscle fibers. J Muscle Res Cell Motil 2010; 31:195-205. [DOI: 10.1007/s10974-010-9223-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 07/21/2010] [Indexed: 10/19/2022]
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Zhao G, Simpson RU. Membrane localization, Caveolin-3 association and rapid actions of vitamin D receptor in cardiac myocytes. Steroids 2010; 75:555-9. [PMID: 20015453 PMCID: PMC2885558 DOI: 10.1016/j.steroids.2009.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 12/03/2009] [Accepted: 12/07/2009] [Indexed: 11/26/2022]
Abstract
The active form of vitamin D, 1alpha, 25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), mediates both genomic and rapid non-genomic actions in heart cells. We have previously shown that the vitamin D receptor (VDR) is located in the t-tubular structure of cardiomyocytes. Here we show that VDR specifically interacts with Caveolin-3 in the t-tubules and sarcolemma of adult rat cardiac myocytes. Co-immunoprecipitation studies using VDR antibodies revealed that Caveolin-3 specifically co-precipitates with the VDR and similarly the VDR is co-precipitated with Caveolin-3 antibody. Confocal immuno-fluorescence microscopy analysis also showed co-localization of VDR and Caveolin-3 in t-tubules and sarcolemma. The non-genomic effects of the functional VDR were studied in electrically stimulated myocytes isolated from adult rat hearts. Sarcomere shortening and re-lengthening were measured in 1,25(OH)(2)D(3) treated cardiac myocytes. A 1nM treatment decreased peak shortening within minutes, suggesting a rapid effect through the membrane-bound VDR. This novel finding of the interaction between VDR and Caveolin-3 is fundamentally important in understanding 1,25(OH)(2)D(3) signal transduction in heart cells and provides further evidence that VDR plays a role in regulation of heart structure and function.
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Affiliation(s)
- Guisheng Zhao
- Department of Pharmacology, University of Michigan, School of Medicine, Ann Arbor, MI 48109, USA
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38
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Zhao G, Simpson RU. Interaction between vitamin D receptor with caveolin-3 and regulation by 1,25-dihydroxyvitamin D3 in adult rat cardiomyocytes. J Steroid Biochem Mol Biol 2010; 121:159-63. [PMID: 20304057 PMCID: PMC2906649 DOI: 10.1016/j.jsbmb.2010.03.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 03/11/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
We show that 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) and a synthetic non-genotropic vitamin D analog agonist, 1a,25(OH)2-lumisterol (JN), exhibit similar rapid effects on sarcomere shortening (contraction) of isolated adult cardiomyocyte. We also report that the vitamin D receptor (VDR) specifically interacts with caveolin-3 in the t-tubules and sarcolemma of isolated adult rat cardiac myocytes. Confocal immunofluorescence microscopy analysis showed co-localization of VDR and caveolin-3 in the t-tubules and sarcolemma of cardiomyocytes. Co-immunoprecipitation studies using VDR antibodies revealed that caveolin-3 specifically co-precipitates with the VDR and similarly the VDR is co-precipitated with caveolin-3 antibody. VDR is also in association with Serca-2, the sarcoplasmic reticulum Ca2+-ATPase, as demonstrated by co-immunoprecipitation, suggesting a role of VDR in regulating cardiac contractility by direct interaction with Serca-2. Treatment of isolated adult rat cardiomyocytes with 10 nM 1,25(OH)2D3 for 1 h caused decreased association between VDR and caveolin-3. These discoveries of the association between VDR and caveolin-3 and the regulation of this interaction by 1,25(OH)2D3 are fundamentally important in understanding 1,25(OH)2D3 signal transduction in heart cells and suggest a novel mechanism for VDR in the regulation of heart structure and function.
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Affiliation(s)
| | - Robert U. Simpson
- Address correspondence to: Robert U. Simpson, Department of Pharmacology, University of Michigan Medical School, 1150 West Medical Center Drive. MSRB III, Room 1301. Ann Arbor, MI 48109. Phone: (734) 763-3255. Fax: (734) 763-4450.
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39
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Klinge L, Harris J, Sewry C, Charlton R, Anderson L, Laval S, Chiu YH, Hornsey M, Straub V, Barresi R, Lochmüller H, Bushby K. Dysferlin associates with the developing T-tubule system in rodent and human skeletal muscle. Muscle Nerve 2010; 41:166-73. [PMID: 20082313 DOI: 10.1002/mus.21166] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mutations in the dysferlin gene cause limb-girdle muscular dystrophy type 2B, Miyoshi myopathy, and distal anterior compartment myopathy. Dysferlin mainly localizes to the sarcolemma in mature skeletal muscle where it is implicated in membrane fusion and repair. In different forms of muscular dystrophy, a predominantly cytoplasmic localization of dysferlin can be observed in regenerating myofibers, but the subcellular compartment responsible for this labeling pattern is not yet known. We have previously demonstrated an association of dysferlin with the developing T-tubule system in vitro. To investigate the role of dysferlin in adult skeletal muscle regeneration, we studied dysferlin localization at high resolution in a rat model of regeneration and found that the subcellular labeling of dysferlin colocalizes with the developing T-tubule system. Furthermore, ultrastructural analysis of dysferlin-deficient muscle revealed primary T-tubule anomalies similar to those seen in caveolin-3-deficient muscle. These findings indicate that dysferlin is necessary for correct T-tubule formation, and dysferlin-deficient skeletal muscle is characterized by abnormally configured T-tubules.
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Affiliation(s)
- Lars Klinge
- Institute of Human Genetics, International Centre for Life, University of Newcastle, Newcastle-upon-Tyne NE1 3BZ, UK
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40
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McGrath KF, Yuki A, Manaka Y, Tamaki H, Saito K, Takekura H. Morphological characteristics of cardiac calcium release units in animals with metabolic and circulatory disorders. J Muscle Res Cell Motil 2009; 30:225-31. [PMID: 19924547 DOI: 10.1007/s10974-009-9191-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 11/01/2009] [Indexed: 11/24/2022]
Abstract
Metabolic and circulatory disorders such as diabetes and hypertension are associated with cardiac dysfunction. Research on these types of experimental animals has observed abnormal calcium (Ca(2+)) sparks and waves in cells; a potential mechanism altering excitation-contraction (e-c) coupling in the myocardium. The e-c coupling depends on the intricate spatial relationship between the sarcolemma and sarcoplasmic reticulum calcium release units (CRU's). The objective of this study was to assess for a presence or absence of abnormalities in CRU's from type II diabetic and hypertensive rat models. Myocardial tissue underwent perfusion fixation followed by selective staining of the CRU's and the features observed using a high voltage electron microscope. Results revealed both diabetic groups had significant increases in body weight, a tendency toward an enlarged heart, and a significant disruption of the CRU's and displacement of transverse (t)-tubules in a longitudinal direction. The hypertensive model characteristically showed a dramatic increase in heart size, a significant increase in disrupted CRU's and a tendency towards longitudinal t-tubule orientation. We propose the two disorders of diabetes and hypertension have a similar etiology of cardiomyopathy resulting, in part, from an increase in the number of incomplete CRU's, due to a morphological change in the architecture and orientation of the t-tubules. These architectural changes could potentially explain the impaired calcium signaling previously observed in diabetic and hypertensive cardiomyopathy.
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Affiliation(s)
- Kelly F McGrath
- Department of Physiological Sciences, National Institute of Fitness and Sports, Kanoya, Kagoshima, Japan.
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41
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T-tubule disorganization and defective excitation-contraction coupling in muscle fibers lacking myotubularin lipid phosphatase. Proc Natl Acad Sci U S A 2009; 106:18763-8. [PMID: 19846786 DOI: 10.1073/pnas.0900705106] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle contraction is triggered by the excitation-contraction (E-C) coupling machinery residing at the triad, a membrane structure formed by the juxtaposition of T-tubules and sarcoplasmic reticulum (SR) cisternae. The formation and maintenance of this structure is key for muscle function but is not well characterized. We have investigated the mechanisms leading to X-linked myotubular myopathy (XLMTM), a severe congenital disorder due to loss of function mutations in the MTM1 gene, encoding myotubularin, a phosphoinositide phosphatase thought to have a role in plasma membrane homeostasis and endocytosis. Using a mouse model of the disease, we report that Mtm1-deficient muscle fibers have a decreased number of triads and abnormal longitudinally oriented T-tubules. In addition, SR Ca(2+) release elicited by voltage-clamp depolarizations is strongly depressed in myotubularin-deficient muscle fibers, with myoplasmic Ca(2+) removal and SR Ca(2+) content essentially unaffected. At the molecular level, Mtm1-deficient myofibers exhibit a 3-fold reduction in type 1 ryanodine receptor (RyR1) protein level. These data reveal a critical role of myotubularin in the proper organization and function of the E-C coupling machinery and strongly suggest that defective RyR1-mediated SR Ca(2+) release is responsible for the failure of muscle function in myotubular myopathy.
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42
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Fernando P, Sandoz JS, Ding W, de Repentigny Y, Brunette S, Kelly JF, Kothary R, Megeney LA. Bin1 SRC homology 3 domain acts as a scaffold for myofiber sarcomere assembly. J Biol Chem 2009; 284:27674-86. [PMID: 19633357 DOI: 10.1074/jbc.m109.029538] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In skeletal muscle development, the genes and regulatory factors that govern the specification of myocytes are well described. Despite this knowledge, the mechanisms that regulate the coordinated assembly of myofiber proteins into the functional contractile unit or sarcomere remain undefined. Here we explored the hypothesis that modular domain proteins such as Bin1 coordinate protein interactions to promote sarcomere formation. We demonstrate that Bin1 facilitates sarcomere organization through protein-protein interactions as mediated by the Src homology 3 (SH3) domain. We observed a profound disorder in myofiber size and structural organization in a murine model expressing the Bin1 SH3 region. In addition, satellite cell-derived myogenesis was limited despite the accumulation of skeletal muscle-specific proteins. Our experiments revealed that the Bin1 SH3 domain formed transient protein complexes with both actin and myosin filaments and the pro-myogenic kinase Cdk5. Bin1 also associated with a Cdk5 phosphorylation domain of titin. Collectively, these observations suggest that Bin1 displays protein scaffold-like properties and binds with sarcomeric factors important in directing sarcomere protein assembly and myofiber maturation.
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Affiliation(s)
- Pasan Fernando
- The Sprott Center for Stem Cell Research, Regenerative Medicine Program, Ottawa, Ontario K1H 8L6, Canada.
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43
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Hayashi T, Martone ME, Yu Z, Thor A, Doi M, Holst MJ, Ellisman MH, Hoshijima M. Three-dimensional electron microscopy reveals new details of membrane systems for Ca2+ signaling in the heart. J Cell Sci 2009; 122:1005-13. [PMID: 19295127 DOI: 10.1242/jcs.028175] [Citation(s) in RCA: 198] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the current study, the three-dimensional (3D) topologies of dyadic clefts and associated membrane organelles were mapped in mouse ventricular myocardium using electron tomography. The morphological details and the distribution of membrane systems, including transverse tubules (T-tubules), junctional sarcoplasmic reticulum (SR) and vicinal mitochondria, were determined and presumed to be crucial for controlling cardiac Ca(2+) dynamics. The geometric complexity of T-tubules that varied in diameter with frequent branching was clarified. Dyadic clefts were intricately shaped and remarkably small (average 4.39x10(5) nm(3), median 2.81x10(5) nm(3)). Although a dyadic cleft of average size could hold maximum 43 ryanodine receptor (RyR) tetramers, more than one-third of clefts were smaller than the size that is able to package as many as 15 RyR tetramers. The dyadic clefts were also adjacent to one another (average end-to-end distance to the nearest dyadic cleft, 19.9 nm) and were distributed irregularly along T-tubule branches. Electron-dense structures that linked membrane organelles were frequently observed between mitochondrial outer membranes and SR or T-tubules. We, thus, propose that the topology of dyadic clefts and the neighboring cellular micro-architecture are the major determinants of the local control of Ca(2+) in the heart, including the establishment of the quantal nature of SR Ca(2+) releases (e.g. Ca(2+) sparks).
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Affiliation(s)
- Takeharu Hayashi
- The Center for Research in Biological Systems, University of California San Diego, La Jolla, CA 92093, USA
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44
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Rigoard P, Buffenoir K, Wager M, Bauche S, Giot JP, Lapierre F. [Molecular architecture of the sarcoplasmic reticulum and its role in the ECC]. Neurochirurgie 2009; 55 Suppl 1:S83-91. [PMID: 19233437 DOI: 10.1016/j.neuchi.2008.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 05/09/2008] [Indexed: 11/16/2022]
Abstract
The sarcoplasmic reticulum (SR) plays a fundamental role in excitation-contraction coupling, which propagates the electric signal conversion along the muscle fiber's plasmic membrane to a mechanical event manifested as a muscle contraction. It plays a crucial role in calcium homeostasis and intracellular calcium storage control (storage, liberation and uptake) necessary for fiber muscle contraction and then relaxation. These functions take place at the triad, made up of individualized SR subdomains where the protein-specific organization provides efficient and fast coupling. Ryanodine receptors (RyR) and dihydropyridine receptors (DHPR) mainly act in calcium exchanges in the SR. This particular structural and molecular architecture must be correlated to its functional specificity.
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Affiliation(s)
- P Rigoard
- Service de neurochirurgie, CHU La Milétrie, 2, rue de la Milétrie, BP 577, 86021 Poitiers cedex, France.
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45
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Salmons S, Jarvis JC. Functional Electrical Stimulation of Denervated Muscles: An Experimental Evaluation. Artif Organs 2008; 32:597-603. [PMID: 18782128 DOI: 10.1111/j.1525-1594.2008.00608.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stanley Salmons
- Muscle Research Group, Department of Human Anatomy & Cell Biology, University of Liverpool, Liverpool, UK.
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46
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Jiménez-Moreno R, Wang ZM, Gerring RC, Delbono O. Sarcoplasmic reticulum Ca2+ release declines in muscle fibers from aging mice. Biophys J 2008; 94:3178-88. [PMID: 18178643 PMCID: PMC2275691 DOI: 10.1529/biophysj.107.118786] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Accepted: 12/03/2007] [Indexed: 11/18/2022] Open
Abstract
This study hypothesized that decline in sarcoplasmic reticulum (SR) Ca(2+) release and maximal SR-releasable Ca(2+) contributes to decreased specific force with aging. To test it, we recorded electrically evoked maximal isometric specific force followed by 4-chloro-m-cresol (4-CmC)-evoked maximal contracture force in single intact fibers from the mouse flexor digitorum brevis muscle. Significant differences in tetanic, but not in 4-CmC-evoked, contracture forces were recorded in fibers from aging mice as compared to younger mice. Peak intracellular Ca(2+) in response to 4-CmC did not differ significantly. SR Ca(2+) release was recorded in whole-cell patch-clamped fibers in the linescan mode of confocal microscopy using a low-affinity Ca(2+) indicator (Oregon green bapta-5N) with high-intracellular ethylene glycol-bis(alpha-aminoethyl ether)-N,N,N'N'-tetraacetic acid (20 mM). Maximal SR Ca(2+) release, but not voltage dependence, was significantly changed in fibers from old compared to young mice. Increasing the duration of fiber depolarization did not increase the maximal rate of SR Ca(2+) release in fibers from old compared to young mice. Voltage-dependent inactivation of SR Ca(2+) release did not differ significantly between fibers from young and old mice. These findings indicate that alterations in excitation-contraction coupling, but not in maximal SR-releasable Ca(2+), account for the age-dependent decline in intracellular Ca(2+) mobilization and specific force.
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Affiliation(s)
- Ramón Jiménez-Moreno
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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47
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Rodney GG. Calmodulin in adult mammalian skeletal muscle: localization and effect on sarcoplasmic reticulum Ca2+ release. Am J Physiol Cell Physiol 2008; 294:C1288-97. [PMID: 18322139 DOI: 10.1152/ajpcell.00033.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calmodulin is a ubiquitous Ca2+ binding protein that binds to ryanodine rectors (RyR) and is thought to modulate its activity. Here we evaluated the effects of recombinant calmodulin on the rate of occurrence and spatial properties of Ca2+ sparks as an assay of activation in saponin-permeabilized mouse myofibers. Control myofibers exhibited a time-dependent increase and subsequent decrease in spark frequency. Recombinant wild-type calmodulin prevented the time-dependent appearance of Ca2+ sparks and decreased the derived Ca2+ flux from the sarcoplasmic reticulum during a spark by approximately 37%. A recombinant Ca2+-insensitive form of calmodulin resulted in an instantaneous increase in spark frequency as well as an increase in the derived Ca2+ flux by approximately 24%. Endogenous calmodulin was found to primarily localize to the Z-line. Surprisingly, removal of endogenous calmodulin did not alter the time dependence of Ca2+ spark appearance. These results indicate that calmodulin may not be essential for RyR1-dependent Ca2+ release in adult mammalian skeletal muscle.
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Affiliation(s)
- George G Rodney
- Department of Organizational Systems & Adult Health, University of Maryland School of Nursing, Baltimore, MD 21201, USA.
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48
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T-tubule formation in cardiacmyocytes: two possible mechanisms? J Muscle Res Cell Motil 2007; 28:231-41. [PMID: 17940841 DOI: 10.1007/s10974-007-9121-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Accepted: 09/20/2007] [Indexed: 10/22/2022]
Abstract
We have followed the differentiation of transverse (T) tubules and of the associations between sarcoplasmic reticulum (SR) and either the plasmalemma (peripheral couplings) or the T tubules (dyads) in postnatal rat ventricular myocytes using electron microscopy. Dyads and peripheral couplings are collectively called Ca(2+) Release Units (CRUs) because they are the sites at which Ca(2+) is released from the SR. Profiles of T tubules, caveolae and dyads are mostly at the cell edge in early postnatal days and are found with increased frequency in the cell interior during the first two postnatal weeks. Using ferritin to trace continuity of T tubules lumen with the extracellular space, we find that some of T tubules (between approximately 6 and 25%), either singly or within dyads, lack ferritin in their lumen. The percentage of tubules that do not contain ferritin decreases slightly during postnatal differentiation and is not very different at the cells' edges and interior. We propose that T tubules form as invaginations of the plasmalemma that penetrate inward driven by accrual of membrane lipids and specific proteins. This occurs by a dual mechanism: either by the independent flow of SR and T tubule proteins into the two separate membranes or by the fusion of preformed vesicle tandems into the dyads. Most of the CRUs (approximately 86%) are constituted by peripheral couplings and ferritin containing dyads, thus constituting CRUs in which Ca(2+ )release from the SR is initiated by a membrane depolarization. In the remaining CRUs, activation of Ca(2+) release must be dependent on some other mechanisms.
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49
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Ashley Z, Salmons S, Boncompagni S, Protasi F, Russold M, Lanmuller H, Mayr W, Sutherland H, Jarvis JC. Effects of chronic electrical stimulation on long-term denervated muscles of the rabbit hind limb. J Muscle Res Cell Motil 2007; 28:203-17. [PMID: 17906933 DOI: 10.1007/s10974-007-9119-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
Abstract
We investigated the extent to which activity induced by chronic electrical stimulation could restore the mass and contractile function of rabbit tibialis anterior (TA) muscles that had undergone atrophy as a result of prolonged denervation. Denervation was carried out by selectively interrupting the motor nerve branches to the ankle dorsiflexors in one hind limb. Stimulators were implanted, with electrodes on the superficial and deep surfaces of the denervated TA muscle. Ten weeks later, the mass and mid-belly cross-sectional area (CSA) of TA muscles subjected to denervation alone had fallen to approximately 40% of normal. At this stage, stimulators in the other rabbits were activated for 1 h/day to deliver 20-ms rectangular bipolar constant-current pulses of 4 mA amplitude at 20 Hz with a duty cycle of 1s ON/2s OFF, a total of 24,000 impulses/day. The animals were examined after a further 2, 6 or 10 weeks. Stimulation restored the wet weight of the denervated muscles to values not significantly different to those of normal, innervated controls. It increased CSA from 39% to 66% of normal, and there was a commensurate increase in maximum isometric tetanic force from 27% to 50% of normal. Light and electron microscopic examination revealed a marked improvement in the size, packing, and internal organization of the stimulated-denervated muscle fibres, suggestive of an ongoing process of restoration. Excitability, contractile speed, power, and fatigue resistance had not, however, been restored to normal levels after 10 weeks of stimulation. Similar results were found for muscles that had been denervated for 39 weeks and then stimulated for 12 weeks. The study demonstrates worthwhile benefits of long-term electrical stimulation in the treatment of established denervation atrophy.
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Affiliation(s)
- Zoe Ashley
- Muscle Research Group, Department of Human Anatomy & Cell Biology, School of Biomedical Sciences, University of Liverpool, The Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
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50
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Stroffekova K. Ca2+/CaM-dependent inactivation of the skeletal muscle L-type Ca2+ channel (Cav1.1). Pflugers Arch 2007; 455:873-84. [PMID: 17899167 DOI: 10.1007/s00424-007-0344-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 09/05/2007] [Indexed: 10/22/2022]
Abstract
Ca2+-dependent modulation via calmodulin (CaM) has been documented for most high-voltage-activated Ca2+ channels, but whether the skeletal muscle L-type channel (Cav1.1) exhibits this property has been unknown. In this paper, whole-cell current and fluorescent resonance energy transfer (FRET) recordings were obtained from cultured mouse myotubes to test for potential involvement of CaM in function of Cav1.1. When prolonged depolarization (800 ms) was used to evoke Cav1.1 currents in normal myotubes, the fraction of current remaining at the end of the pulse displayed classic signs of Ca2+-dependent inactivation (CDI), including U-shaped voltage dependence, maximal inactivation (approximately 30%) at potentials eliciting maximal inward current, and virtual elimination of inactivation when Ba2+ replaced external Ca2+ or when 10 mM BAPTA was included in the pipette solution. Furthermore, CDI was virtually eliminated (from 30 to 8%) in normal myotubes overexpressing mutant CaM (CaM1234) that does not bind Ca2+, whereas CDI was unaltered in myotubes overexpressing wild-type CaM (CaMwt). In addition, a significant FRET signal (E=4.06%) was detected between fluorescently tagged Cav1.1 and CaMwt coexpressed in dysgenic myotubes, demonstrating for the first time that these two proteins associate in vivo. These findings show that CaM associates with and modulates Cav1.1.
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Affiliation(s)
- Katarina Stroffekova
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA.
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