1
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Bouquiaux C, Champagne B, Beaujean P. Multimillion Atom Simulations of Di-8-ANEPPS Chromophores Embedded in a Model Plasma Membrane: Toward the Investigation of Realistic Dyed Cell Membranes. J Chem Inf Model 2024; 64:518-531. [PMID: 38157204 DOI: 10.1021/acs.jcim.3c01568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
A multistep computational approach has been employed to study a multimillion all-atom dyed plasma membrane, with no less than 42 different lipid species spanning the major head groups and a variety of fatty acids, as well as cholesterol, with the objective of investigating its structure and dynamics, as well as its impact on the embedded di-8-ANEPPS dyes. The latter are commonly used as bioimaging probes and serve as local microscopes. So, they provide information on membrane morphology via their second harmonic nonlinear optical (NLO) responses, which have the advantage of being specific to interface regions and sensitive to the chromophore environment. In previous studies, this chromophore has only been studied in simpler membrane models, far from the complexity of real lipid bilayers, while, owing to the ever-increasing computational resources, multimillion lipid bilayers have been studied, giving access to the effects of its heterogeneity. First, using molecular dynamics (MD) simulations, it is found that the combination of lipids produces a more ordered and denser membrane compared to its homogeneous model counterparts, while the local environment of the embedded dyes becomes enriched in phosphatidylcholine. Subsequently, the second harmonic first hyperpolarizability of the probes was calculated at the TDDFT level on selected frames of MD, highlighting the influence of the lipid environment. Due to the complexity of the system, machine learning (ML) tools have been employed to establish relationships between the membrane structural parameters, the orientation of the probes, and their NLO responses. These ML approaches have revealed influential features, including the presence of diacylglycerol lipids close to the dye. On the whole, this work provides a first step toward understanding the cooperation, synergy, and interactions that occur in such complex guest-host environments, which have emerged as new targets for drug design and membrane lipid therapy.
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Affiliation(s)
- Charlotte Bouquiaux
- University of Namur, Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Benoît Champagne
- University of Namur, Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Pierre Beaujean
- University of Namur, Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, rue de Bruxelles, 61, B-5000 Namur, Belgium
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2
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Morgenstern TJ, Nirwan N, Hernández-Ochoa EO, Bibollet H, Choudhury P, Laloudakis YD, Ben Johny M, Bannister RA, Schneider MF, Minor DL, Colecraft HM. Selective posttranslational inhibition of Ca Vβ 1-associated voltage-dependent calcium channels with a functionalized nanobody. Nat Commun 2022; 13:7556. [PMID: 36494348 PMCID: PMC9734117 DOI: 10.1038/s41467-022-35025-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/15/2022] [Indexed: 12/13/2022] Open
Abstract
Ca2+ influx through high-voltage-activated calcium channels (HVACCs) controls diverse cellular functions. A critical feature enabling a singular signal, Ca2+ influx, to mediate disparate functions is diversity of HVACC pore-forming α1 and auxiliary CaVβ1-CaVβ4 subunits. Selective CaVα1 blockers have enabled deciphering their unique physiological roles. By contrast, the capacity to post-translationally inhibit HVACCs based on CaVβ isoform is non-existent. Conventional gene knockout/shRNA approaches do not adequately address this deficit owing to subunit reshuffling and partially overlapping functions of CaVβ isoforms. Here, we identify a nanobody (nb.E8) that selectively binds CaVβ1 SH3 domain and inhibits CaVβ1-associated HVACCs by reducing channel surface density, decreasing open probability, and speeding inactivation. Functionalizing nb.E8 with Nedd4L HECT domain yielded Chisel-1 which eliminated current through CaVβ1-reconstituted CaV1/CaV2 and native CaV1.1 channels in skeletal muscle, strongly suppressed depolarization-evoked Ca2+ influx and excitation-transcription coupling in hippocampal neurons, but was inert against CaVβ2-associated CaV1.2 in cardiomyocytes. The results introduce an original method for probing distinctive functions of ion channel auxiliary subunit isoforms, reveal additional dimensions of CaVβ1 signaling in neurons, and describe a genetically-encoded HVACC inhibitor with unique properties.
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Affiliation(s)
- Travis J. Morgenstern
- grid.239585.00000 0001 2285 2675Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY USA
| | - Neha Nirwan
- grid.266102.10000 0001 2297 6811Cardiovascular Research Institute, University of California, San Francisco, CA USA
| | - Erick O. Hernández-Ochoa
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Hugo Bibollet
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Papiya Choudhury
- grid.239585.00000 0001 2285 2675Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY USA
| | - Yianni D. Laloudakis
- grid.239585.00000 0001 2285 2675Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY USA
| | - Manu Ben Johny
- grid.239585.00000 0001 2285 2675Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY USA
| | - Roger A. Bannister
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA ,grid.411024.20000 0001 2175 4264Department of Pathology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Martin F. Schneider
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Daniel L. Minor
- grid.266102.10000 0001 2297 6811Cardiovascular Research Institute, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811Department of Biochemistry and Biophysics, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA USA ,grid.184769.50000 0001 2231 4551Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Henry M. Colecraft
- grid.239585.00000 0001 2285 2675Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY USA ,grid.239585.00000 0001 2285 2675Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY USA
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3
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Lukyanenko V, Muriel J, Garman D, Breydo L, Bloch RJ. Elevated Ca 2+ at the triad junction underlies dysregulation of Ca 2+ signaling in dysferlin-null skeletal muscle. Front Physiol 2022; 13:1032447. [PMID: 36406982 PMCID: PMC9669649 DOI: 10.3389/fphys.2022.1032447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/14/2022] [Indexed: 11/05/2022] Open
Abstract
Dysferlin-null A/J myofibers generate abnormal Ca2+ transients that are slightly reduced in amplitude compared to controls. These are further reduced in amplitude by hypoosmotic shock and often appear as Ca2+ waves (Lukyanenko et al., J. Physiol., 2017). Ca2+ waves are typically associated with Ca2+-induced Ca2+ release, or CICR, which can be myopathic. We tested the ability of a permeable Ca2+ chelator, BAPTA-AM, to inhibit CICR in injured dysferlin-null fibers and found that 10-50 nM BAPTA-AM suppressed all Ca2+ waves. The same concentrations of BAPTA-AM increased the amplitude of the Ca2+ transient in A/J fibers to wild type levels and protected transients against the loss of amplitude after hypoosmotic shock, as also seen in wild type fibers. Incubation with 10 nM BAPTA-AM led to intracellular BAPTA concentrations of ∼60 nM, as estimated with its fluorescent analog, Fluo-4AM. This should be sufficient to restore intracellular Ca2+ to levels seen in wild type muscle. Fluo-4AM was ∼10-fold less effective than BAPTA-AM, however, consistent with its lower affinity for Ca2+. EGTA, which has an affinity for Ca2+ similar to BAPTA, but with much slower kinetics of binding, was even less potent when introduced as the -AM derivative. By contrast, a dysferlin variant with GCaMP6fu in place of its C2A domain accumulated at triad junctions, like wild type dysferlin, and suppressed all abnormal Ca2+ signaling. GCaMP6fu introduced as a Venus chimera did not accumulate at junctions and failed to suppress abnormal Ca2+ signaling. Our results suggest that leak of Ca2+ into the triad junctional cleft underlies dysregulation of Ca2+ signaling in dysferlin-null myofibers, and that dysferlin's C2A domain suppresses abnormal Ca2+ signaling and protects muscle against injury by binding Ca2+ in the cleft.
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Affiliation(s)
- Valeriy Lukyanenko
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Joaquin Muriel
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Daniel Garman
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
- Program in Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, United States
| | - Leonid Breydo
- Formulation Development, Regeneron Pharmaceuticals, Tarrytown, NY, United States
| | - Robert J. Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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4
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Demonbreun AR, Bogdanovic E, Vaught LA, Reiser NL, Fallon KS, Long AM, Oosterbaan CC, Hadhazy M, Page PG, Joseph PRB, Cowen G, Telenson AM, Khatri A, Sadleir KR, Vassar R, McNally EM. A conserved annexin A6-mediated membrane repair mechanism in muscle, heart, and nerve. JCI Insight 2022; 7:158107. [PMID: 35866481 PMCID: PMC9431694 DOI: 10.1172/jci.insight.158107] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/08/2022] [Indexed: 11/21/2022] Open
Abstract
Membrane instability and disruption underlie myriad acute and chronic disorders. Anxa6 encodes the membrane-associated protein annexin A6 and was identified as a genetic modifier of muscle repair and muscular dystrophy. To evaluate annexin A6’s role in membrane repair in vivo, we inserted sequences encoding green fluorescent protein (GFP) into the last coding exon of Anxa6. Heterozygous Anxa6gfp mice expressed a normal pattern of annexin A6 with reduced annexin A6GFP mRNA and protein. High-resolution imaging of wounded muscle fibers showed annexin A6GFP rapidly formed a repair cap at the site of injury. Injured cardiomyocytes and neurons also displayed repair caps after wounding, highlighting annexin A6–mediated repair caps as a feature in multiple cell types. Using surface plasmon resonance, we showed recombinant annexin A6 bound phosphatidylserine-containing lipids in a Ca2+- and dose-dependent fashion with appreciable binding at approximately 50 μM Ca2+. Exogenously added recombinant annexin A6 localized to repair caps and improved muscle membrane repair capacity in a dose-dependent fashion without disrupting endogenous annexin A6 localization, indicating annexin A6 promotes repair from both intracellular and extracellular compartments. Thus, annexin A6 orchestrates repair in multiple cell types, and recombinant annexin A6 may be useful in additional chronic disorders beyond skeletal muscle myopathies.
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Affiliation(s)
| | - Elena Bogdanovic
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Lauren A Vaught
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Nina L Reiser
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Katherine S Fallon
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Ashlee M Long
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Claire C Oosterbaan
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Michele Hadhazy
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | | | | | - Gabrielle Cowen
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | | | - Ammaarah Khatri
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Katherine R Sadleir
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Robert Vassar
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Elizabeth M McNally
- Center for Genetic Medicine.,Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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5
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Hughes DC, Hardee JP, Waddell DS, Goodman CA. CORP: Gene delivery into murine skeletal muscle using in vivo electroporation. J Appl Physiol (1985) 2022; 133:41-59. [PMID: 35511722 DOI: 10.1152/japplphysiol.00088.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The strategy of gene delivery into skeletal muscles has provided exciting avenues in identifying new potential therapeutics towards muscular disorders and addressing basic research questions in muscle physiology through overexpression and knockdown studies. In vivo electroporation methodology offers a simple, rapidly effective technique for the delivery of plasmid DNA into post-mitotic skeletal muscle fibers and the ability to easily explore the molecular mechanisms of skeletal muscle plasticity. The purpose of this review is to describe how to robustly electroporate plasmid DNA into different hindlimb muscles of rodent models. Further, key parameters (e.g., voltage, hyaluronidase, plasmid concentration) which contribute to the successful introduction of plasmid DNA into skeletal muscle fibers will be discussed. In addition, details on processing tissue for immunohistochemistry and fiber cross-sectional area (CSA) analysis will be outlined. The overall goal of this review is to provide the basic and necessary information needed for successful implementation of in vivo electroporation of plasmid DNA and thus open new avenues of discovery research in skeletal muscle physiology.
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Affiliation(s)
- David C Hughes
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Justin P Hardee
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - David S Waddell
- Department of Biology, University of North Florida, Jacksonville, FL, United States
| | - Craig A Goodman
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
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6
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Ghosh R, Dumarieh R, Xiao Y, Frederick KK. Stability of the nitroxide biradical AMUPol in intact and lysed mammalian cells. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 336:107150. [PMID: 35151975 PMCID: PMC8961433 DOI: 10.1016/j.jmr.2022.107150] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Dynamic Nuclear Polarization (DNP) enhanced solid state NMR increases experimental sensitivity, potentially enabling detection of biomolecules at their physiological concentrations. The sensitivity of DNP experiments is due to the transfer of polarization from electron spins of free radicals to the nuclear spins of interest. Here, we investigate the reduction of AMUPol in both lysed and intact HEK293 cells. We find that nitroxide radicals are reduced with first order reduction kinetics by cell lysates at a rate of ∼ 12% of the added nitroxide radical concentration per hour. We also found that electroporation delivered a consistent amount of AMUPol to intact cells and that nitroxide radicals are reduced just slightly more rapidly (∼15% per hour) by intact cells than by cell lysates. The two nitroxide radicals of AMUPol are reduced independently and this leads to considerable accumulation of the DNP-silent monoradical form of AMUPol, particularly in preparations of intact cells where nearly half of the AMUPol is already reduced to the DNP silent monoradical form at the earliest experimental time points. This confirms that the loss of the DNP-active biradical form of AMUPol is faster than the nitroxide reduction rate. Finally, we investigate the effect of adding N-ethyl maleimide, a well-known inhibitor of thiol (-SH) group-based reduction of nitroxide biradicals in cells, on AMUPol reduction, cellular viability, and DNP performance. Although pre-treatment of cells with NEM effectively inhibited the reduction of AMUPol, exposure to NEM compromised cellular viability and, surprisingly, did not improve DNP performance. Collectively, these results indicate that, currently, the most effective strategy to obtain high DNP enhancements for DNP-assisted in-cell NMR is to minimize room temperature contact times with cellular constituents and suggest that the development of bio-resistant polarization agents for DNP could considerably increase the sensitivity of DNP-assisted in-cell NMR experiments.
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Affiliation(s)
- Rupam Ghosh
- Department of Biophysics, UT Southwestern Medical Center, Dallas, 75390-8816, United States
| | - Rania Dumarieh
- Department of Biophysics, UT Southwestern Medical Center, Dallas, 75390-8816, United States
| | - Yiling Xiao
- Department of Biophysics, UT Southwestern Medical Center, Dallas, 75390-8816, United States
| | - Kendra K Frederick
- Department of Biophysics, UT Southwestern Medical Center, Dallas, 75390-8816, United States; Center for Neurodegenerative and Alzheimer's Disease, UT Southwestern Medical Center, Dallas 75390, United States.
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7
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Ghosh R, Xiao Y, Kragelj J, Frederick KK. In-Cell Sensitivity-Enhanced NMR of Intact Viable Mammalian Cells. J Am Chem Soc 2021; 143:18454-18466. [PMID: 34724614 DOI: 10.1021/jacs.1c06680] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
NMR has the resolution and specificity to determine atomic-level protein structures of isotopically labeled proteins in complex environments, and with the sensitivity gains conferred by dynamic nuclear polarization (DNP), NMR has the sensitivity to detect proteins at their endogenous concentrations. However, DNP sensitivity enhancements are critically dependent on experimental conditions and sample composition. While some of these conditions are theoretically compatible with cellular viability, the effects of others on cellular sample integrity are unknown. Uncertainty about the integrity of cellular samples limits the utility of experimental outputs of in-cell experiments. Using several measures, we establish conditions that support DNP enhancements that can enable detection of micromolar concentrations of proteins in experimentally tractable times that are compatible with cellular viability. Taken together, we establish DNP-assisted MAS NMR as a technique for structural investigations of biomolecules in intact viable cells that can be phenotyped both before and after NMR experiments.
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Affiliation(s)
- Rupam Ghosh
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States
| | - Yiling Xiao
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States
| | - Jaka Kragelj
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States
| | - Kendra K Frederick
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States.,Center for Alzheimer's and Neurodegenerative Disease, UT Southwestern Medical Center, Dallas, Texas 75390, United States
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8
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Liu Z, Chaillou T, Santos Alves E, Mader T, Jude B, Ferreira DMS, Hynynen H, Cheng AJ, Jonsson WO, Pironti G, Andersson DC, Kenne E, Ruas JL, Tavi P, Lanner JT. Mitochondrial NDUFA4L2 is a novel regulator of skeletal muscle mass and force. FASEB J 2021; 35:e22010. [PMID: 34724256 DOI: 10.1096/fj.202100066r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 01/07/2023]
Abstract
The hypoxia-inducible nuclear-encoded mitochondrial protein NADH dehydrogenase (ubiquinone) 1 alpha subcomplex, 4-like 2 (NDUFA4L2) has been demonstrated to decrease oxidative phosphorylation and production of reactive oxygen species in neonatal cardiomyocytes, brain tissue and hypoxic domains of cancer cells. Prolonged local hypoxia can negatively affect skeletal muscle size and tissue oxidative capacity. Although skeletal muscle is a mitochondrial rich, oxygen sensitive tissue, the role of NDUFA4L2 in skeletal muscle has not previously been investigated. Here we ectopically expressed NDUFA4L2 in mouse skeletal muscles using adenovirus-mediated expression and in vivo electroporation. Moreover, femoral artery ligation (FAL) was used as a model of peripheral vascular disease to induce hind limb ischemia and muscle damage. Ectopic NDUFA4L2 expression resulted in reduced mitochondrial respiration and reactive oxygen species followed by lowered AMP, ADP, ATP, and NAD+ levels without affecting the overall protein content of the mitochondrial electron transport chain. Furthermore, ectopically expressed NDUFA4L2 caused a ~20% reduction in muscle mass that resulted in weaker muscles. The loss of muscle mass was associated with increased gene expression of atrogenes MurF1 and Mul1, and apoptotic genes caspase 3 and Bax. Finally, we showed that NDUFA4L2 was induced by FAL and that the Ndufa4l2 mRNA expression correlated with the reduced capacity of the muscle to generate force after the ischemic insult. These results show, for the first time, that mitochondrial NDUFA4L2 is a novel regulator of skeletal muscle mass and force. Specifically, induced NDUFA4L2 reduces mitochondrial activity leading to lower levels of important intramuscular metabolites, including adenine nucleotides and NAD+ , which are hallmarks of mitochondrial dysfunction and hence shows that dysfunctional mitochondrial activity may drive muscle wasting.
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Affiliation(s)
- Zhengye Liu
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Thomas Chaillou
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Estela Santos Alves
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Theresa Mader
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Baptiste Jude
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Duarte M S Ferreira
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Heidi Hynynen
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Arthur J Cheng
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - William O Jonsson
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Gianluigi Pironti
- Department of Physiology and Pharmacology, Medical Cardiac and Skeletal Muscle Research, Karolinska Institutet, Stockholm, Sweden
| | - Daniel C Andersson
- Department of Physiology and Pharmacology, Medical Cardiac and Skeletal Muscle Research, Karolinska Institutet, Stockholm, Sweden.,Heart, Vascular and Neurology Theme, Cardiology Unit, Karolinska University Hospital, Stockholm, Sweden
| | - Ellinor Kenne
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
| | - Jorge L Ruas
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Pasi Tavi
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Johanna T Lanner
- Department of Physiology and Pharmacology, Molecular Muscle Physiology and Pathophysiology, Karolinska Institutet, Stockholm, Sweden
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9
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Massart J, Sjögren RJO, Egan B, Garde C, Lindgren M, Gu W, Ferreira DMS, Katayama M, Ruas JL, Barrès R, O'Gorman DJ, Zierath JR, Krook A. Endurance exercise training-responsive miR-19b-3p improves skeletal muscle glucose metabolism. Nat Commun 2021; 12:5948. [PMID: 34642330 PMCID: PMC8511155 DOI: 10.1038/s41467-021-26095-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 09/09/2021] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle is a highly adaptable tissue and remodels in response to exercise training. Using short RNA sequencing, we determine the miRNA profile of skeletal muscle from healthy male volunteers before and after a 14-day aerobic exercise training regime. Among the exercise training-responsive miRNAs identified, miR-19b-3p was selected for further validation. Overexpression of miR-19b-3p in human skeletal muscle cells increases insulin signaling, glucose uptake, and maximal oxygen consumption, recapitulating the adaptive response to aerobic exercise training. Overexpression of miR-19b-3p in mouse flexor digitorum brevis muscle enhances contraction-induced glucose uptake, indicating that miR-19b-3p exerts control on exercise training-induced adaptations in skeletal muscle. Potential targets of miR-19b-3p that are reduced after aerobic exercise training include KIF13A, MAPK6, RNF11, and VPS37A. Amongst these, RNF11 silencing potentiates glucose uptake in human skeletal muscle cells. Collectively, we identify miR-19b-3p as an aerobic exercise training-induced miRNA that regulates skeletal muscle glucose metabolism.
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Affiliation(s)
- Julie Massart
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Rasmus J O Sjögren
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Brendan Egan
- Department of Physiology and Pharmacology, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
- Department of Health & Human Performance, Dublin City University, Dublin, Ireland
| | - Christian Garde
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Magnus Lindgren
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Weifeng Gu
- University of Massachusetts Medical School, Worchester, MA, USA
- Department of Cell Biology and Neuroscience, University of California at Riverside, Riverside, CA, USA
| | - Duarte M S Ferreira
- Department of Physiology and Pharmacology, Section of Molecular and Cellular Exercise Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Mutsumi Katayama
- Department of Physiology and Pharmacology, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Jorge L Ruas
- Department of Physiology and Pharmacology, Section of Molecular and Cellular Exercise Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Romain Barrès
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Donal J O'Gorman
- Department of Health & Human Performance, Dublin City University, Dublin, Ireland
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
- Department of Physiology and Pharmacology, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Anna Krook
- Department of Physiology and Pharmacology, Section of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
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10
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Voltage sensor movements of Ca V1.1 during an action potential in skeletal muscle fibers. Proc Natl Acad Sci U S A 2021; 118:2026116118. [PMID: 34583989 DOI: 10.1073/pnas.2026116118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
The skeletal muscle L-type Ca2+ channel (CaV1.1) works primarily as a voltage sensor for skeletal muscle action potential (AP)-evoked Ca2+ release. CaV1.1 contains four distinct voltage-sensing domains (VSDs), yet the contribution of each VSD to AP-evoked Ca2+ release remains unknown. To investigate the role of VSDs in excitation-contraction coupling (ECC), we encoded cysteine substitutions on each S4 voltage-sensing segment of CaV1.1, expressed each construct via in vivo gene transfer electroporation, and used in cellulo AP fluorometry to track the movement of each CaV1.1 VSD in skeletal muscle fibers. We first provide electrical measurements of CaV1.1 voltage sensor charge movement in response to an AP waveform. Then we characterize the fluorescently labeled channels' VSD fluorescence signal responses to an AP and compare them with the waveforms of the electrically measured charge movement, the optically measured free myoplasmic Ca2+, and the calculated rate of Ca2+ release from the sarcoplasmic reticulum for an AP, the physiological signal for skeletal muscle fiber activation. A considerable fraction of the fluorescence signal for each VSD occurred after the time of peak Ca2+ release, and even more occurred after the earlier peak of electrically measured charge movement during an AP, and thus could not directly reflect activation of Ca2+ release or charge movement, respectively. However, a sizable fraction of the fluorometric signals for VSDs I, II, and IV, but not VSDIII, overlap the rising phase of charge moved, and even more for Ca2+ release, and thus could be involved in voltage sensor rearrangements or Ca2+ release activation.
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Mitochondria-localized AMPK responds to local energetics and contributes to exercise and energetic stress-induced mitophagy. Proc Natl Acad Sci U S A 2021; 118:2025932118. [PMID: 34493662 PMCID: PMC8449344 DOI: 10.1073/pnas.2025932118] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/05/2021] [Indexed: 12/25/2022] Open
Abstract
Mitochondria form a complex, interconnected reticulum that is maintained through coordination among biogenesis, dynamic fission, and fusion and mitophagy, which are initiated in response to various cues to maintain energetic homeostasis. These cellular events, which make up mitochondrial quality control, act with remarkable spatial precision, but what governs such spatial specificity is poorly understood. Herein, we demonstrate that specific isoforms of the cellular bioenergetic sensor, 5' AMP-activated protein kinase (AMPKα1/α2/β2/γ1), are localized on the outer mitochondrial membrane, referred to as mitoAMPK, in various tissues in mice and humans. Activation of mitoAMPK varies across the reticulum in response to energetic stress, and inhibition of mitoAMPK activity attenuates exercise-induced mitophagy in skeletal muscle in vivo. Discovery of a mitochondrial pool of AMPK and its local importance for mitochondrial quality control underscores the complexity of sensing cellular energetics in vivo that has implications for targeting mitochondrial energetics for disease treatment.
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Jorquera G, Meneses-Valdés R, Rosales-Soto G, Valladares-Ide D, Campos C, Silva-Monasterio M, Llanos P, Cruz G, Jaimovich E, Casas M. High extracellular ATP levels released through pannexin-1 channels mediate inflammation and insulin resistance in skeletal muscle fibres of diet-induced obese mice. Diabetologia 2021; 64:1389-1401. [PMID: 33710396 DOI: 10.1007/s00125-021-05418-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/22/2020] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Skeletal muscle is a key target organ for insulin's actions and is the main regulator of blood glucose. In obese individuals and animal models, there is a chronic low-grade inflammatory state affecting highly metabolic organs, leading to insulin resistance. We have described that adult skeletal muscle fibres can release ATP to the extracellular medium through pannexin-1 (PANX1) channels. Besides, it is known that high extracellular ATP concentrations can act as an inflammatory signal. Here, we propose that skeletal muscle fibres from obese mice release high levels of ATP, through PANX1 channels, promoting inflammation and insulin resistance in muscle cells. METHODS C57BL/6J mice were fed with normal control diet (NCD) or high-fat diet (HFD) for 8 weeks. Muscle fibres were isolated from flexor digitorum brevis (FDB) muscle. PANX1-knockdown FDB fibres were obtained by in vivo electroporation of a short hairpin RNA Panx1 plasmid. We analysed extracellular ATP levels in a luciferin/luciferase assay. Gene expression was studied with quantitative real-time PCR (qPCR). Protein levels were evaluated by immunoblots, ELISA and immunofluorescence. Insulin sensitivity was analysed in a 2-NBDG (fluorescent glucose analogue) uptake assay, immunoblots and IPGTT. RESULTS HFD-fed mice showed significant weight gain and insulin resistance compared with NCD-fed mice. IL-6, IL-1β and TNF-α protein levels were increased in FDB muscle from obese mice. We observed high levels of extracellular ATP in muscle fibres from obese mice (197 ± 55 pmol ATP/μg RNA) compared with controls (32 ± 10 pmol ATP/μg RNA). ATP release in obese mice fibres was reduced by application of 100 μmol/l oleamide (OLE) and 5 μmol/l carbenoxolone (CBX), both PANX1 blockers. mRNA levels of genes linked to inflammation were reduced using OLE, CBX or 2 U/ml ATPase apyrase in muscle fibres from HFD-fed mice. In fibres from mice with pannexin-1 knockdown, we observed diminished extracellular ATP levels (78 ± 10 pmol ATP/μg RNA vs 252 ± 37 pmol ATP/μg RNA in control mice) and a lower expression of inflammatory markers. Moreover, a single pulse of 300 μmol/l ATP to fibres from control mice reduced insulin-mediated 2-NBDG uptake and promoted an elevation in mRNA levels of inflammatory markers. PANX-1 protein levels were increased two- to threefold in skeletal muscle from obese mice compared with control mice. Incubation with CBX increased Akt activation and 2-NBDG uptake in HFD fibres after insulin stimulation, rescuing the insulin resistance condition. Finally, in vivo treatment of HFD-fed mice with CBX (i.p. injection of 10 mg/kg each day) for 14 days, compared with PBS, reduced extracellular ATP levels in skeletal muscle fibres (51 ± 10 pmol ATP/μg RNA vs 222 ± 28 pmol ATP/μg RNA in PBS-treated mice), diminished inflammation and improved glycaemic management. CONCLUSIONS/INTERPRETATION In this work, we propose a novel mechanism for the development of inflammation and insulin resistance in the skeletal muscle of obese mice. We found that high extracellular ATP levels, released by overexpressed PANX1 channels, lead to an inflammatory state and insulin resistance in skeletal muscle fibres of obese mice.
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Affiliation(s)
- Gonzalo Jorquera
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| | - Roberto Meneses-Valdés
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Giovanni Rosales-Soto
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Facultad de Ciencias de la Educación, Universidad San Sebastián, sede Bellavista, Santiago, Chile
| | | | - Cristian Campos
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mónica Silva-Monasterio
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paola Llanos
- Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Gonzalo Cruz
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Enrique Jaimovich
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mariana Casas
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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Balnis J, Drake LA, Vincent CE, Korponay TC, Singer DV, Lacomis D, Lee CG, Elias JA, Jourd'heuil D, Singer HA, Jaitovich A. Succinate Dehydrogenase (SDH)-subunit C Regulates Muscle Oxygen Consumption and Fatigability in an Animal Model of Pulmonary Emphysema. Am J Respir Cell Mol Biol 2021; 65:259-271. [PMID: 33909984 DOI: 10.1165/rcmb.2020-0551oc] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Patients with pulmonary emphysema often develop locomotor muscle dysfunction, which is independently associated with disability and higher mortality in that population. Muscle dysfunction entails reduced force-generation capacity which partially depends on fibers' oxidative potential, yet very little mechanistic research has focused on muscle respiration in pulmonary emphysema. Using a recently established animal model of pulmonary emphysema-driven skeletal muscle dysfunction, we found downregulation of succinate dehydrogenase (SDH) subunit C in association with lower oxygen consumption and fatigue-tolerance in locomotor muscles. Reduced SDH activity has been previously observed in muscles from patients with pulmonary emphysema and we found that SDHC is required to support respiration in cultured muscle cells. Moreover, in-vivo gain of SDH function in emphysema animals muscles resulted in better oxygen consumption rate (OCR) and fatigue tolerance. These changes correlated with a larger number of relatively more oxidative type 2-A and 2X fibers, and a reduced amount of 2B fibers. Our data suggests that SDHC is a key regulator of respiration and fatigability in pulmonary emphysema-driven skeletal muscles, which could be impactful to develop strategies aimed at attenuating this comorbidity.
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Affiliation(s)
- Joseph Balnis
- Albany Medical College, 1092, Albany, New York, United States
| | - Lisa A Drake
- Albany Medical Center, 138207, Albany, New York, United States
| | | | | | - Diane V Singer
- Albany Medical College, 1092, Albany, New York, United States
| | - David Lacomis
- University of Pittsburgh, 6614, Pittsburgh, Pennsylvania, United States
| | - Chun Geun Lee
- Brown University, 6752, Molecular Microbiology and Immunology, Providence, Rhode Island, United States
| | - Jack A Elias
- Brown University, 6752, Medicine and Biologic Science, Providence, Rhode Island, United States
| | | | - Harold A Singer
- Albany Medical College, 1092, Albany, New York, United States
| | - Ariel Jaitovich
- Albany Medical College Center for Cardiovascular Sciences, 150554, Medicine, Albany, New York, United States;
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Foltz SJ, Cui YY, Choo HJ, Hartzell HC. ANO5 ensures trafficking of annexins in wounded myofibers. J Cell Biol 2021; 220:e202007059. [PMID: 33496727 PMCID: PMC7844426 DOI: 10.1083/jcb.202007059] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/20/2020] [Accepted: 12/23/2020] [Indexed: 12/14/2022] Open
Abstract
Mutations in ANO5 (TMEM16E) cause limb-girdle muscular dystrophy R12. Defective plasma membrane repair is a likely mechanism. Using myofibers from Ano5 knockout mice, we show that trafficking of several annexin proteins, which together form a cap at the site of injury, is altered upon loss of ANO5. Annexin A2 accumulates at the wound to nearly twice the level observed in WT fibers, while annexin A6 accumulation is substantially inhibited in the absence of ANO5. Appearance of annexins A1 and A5 at the cap is likewise diminished in the Ano5 knockout. These changes are correlated with an alteration in annexin repair cap fine structure and shedding of annexin-positive vesicles. We conclude that loss of annexin coordination during repair is disrupted in Ano5 knockout mice and underlies the defective repair phenotype. Although ANO5 is a phospholipid scramblase, abnormal repair is rescued by overexpression of a scramblase-defective ANO5 mutant, suggesting a novel, scramblase-independent role of ANO5 in repair.
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Affiliation(s)
| | | | - Hyojung J. Choo
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
| | - H. Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
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15
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Debattisti V, Horn A, Singh R, Seifert EL, Hogarth MW, Mazala DA, Huang KT, Horvath R, Jaiswal JK, Hajnóczky G. Dysregulation of Mitochondrial Ca 2+ Uptake and Sarcolemma Repair Underlie Muscle Weakness and Wasting in Patients and Mice Lacking MICU1. Cell Rep 2020; 29:1274-1286.e6. [PMID: 31665639 PMCID: PMC7007691 DOI: 10.1016/j.celrep.2019.09.063] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/07/2019] [Accepted: 09/20/2019] [Indexed: 01/29/2023] Open
Abstract
Muscle function is regulated by Ca2+, which mediates excitation-contraction coupling, energy metabolism, adaptation to exercise, and sarcolemmal repair. Several of these actions rely on Ca2+ delivery to the mitochondrial matrix via the mitochondrial Ca2+ uniporter, the pore of which is formed by mitochondrial calcium uniporter (MCU). MCU's gatekeeping and cooperative activation are controlled by MICU1. Loss-of-protein mutation in MICU1 causes a neuromuscular disease. To determine the mechanisms underlying the muscle impairments, we used MICU1 patient cells and skeletal muscle-specific MICU1 knockout mice. Both these models show a lower threshold for MCU-mediated Ca2+ uptake. Lack of MICU1 is associated with impaired mitochondrial Ca2+ uptake during excitation-contraction, aerobic metabolism impairment, muscle weakness, fatigue, and myofiber damage during physical activity. MICU1 deficit compromises mitochondrial Ca2+ uptake during sarcolemmal injury, which causes ineffective repair of the damaged myofibers. Thus, dysregulation of mitochondrial Ca2+ uptake hampers myofiber contractile function, likely through energy metabolism and membrane repair.
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Affiliation(s)
- Valentina Debattisti
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Adam Horn
- Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue Northwest, Washington, DC 20010, USA; Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20052, USA
| | - Raghavendra Singh
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Erin L Seifert
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Marshall W Hogarth
- Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue Northwest, Washington, DC 20010, USA; Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20052, USA
| | - Davi A Mazala
- Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue Northwest, Washington, DC 20010, USA; Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20052, USA
| | - Kai Ting Huang
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Rita Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Jyoti K Jaiswal
- Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue Northwest, Washington, DC 20010, USA; Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20052, USA.
| | - György Hajnóczky
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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Definition of a Novel Plasmid-Based Gene Transfection Protocol of Mammalian Skeletal Muscles by Means of In Vivo Electroporation. Int J Mol Sci 2020; 21:ijms21186494. [PMID: 32899477 PMCID: PMC7555604 DOI: 10.3390/ijms21186494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 11/17/2022] Open
Abstract
We describe an original electroporation protocol for in vivo plasmid DNA transfection. The right hind limbs of C57 mice are exposed to a specifically designed train of permeabilizing electric pulses by transcutaneous application of tailored needle electrodes, immediately after the injection of pEGFP-C1 plasmid encoding GFP (Green Fluorescente Protein). The electroporated rodents show a greater GFP expression than the controls at three different time points (4, 10, and 15 days). The electroporated muscles display only mild interstitial myositis, with a significant increase in inflammatory cell infiltrates. Finally, mild gait abnormalities are registered in electroporated mice only in the first 48 h after the treatment. This protocol has proven to be highly efficient in terms of expression levels of the construct, is easy to apply since it does not require surgical exposure of the muscle and is well tolerated by the animals because it does not cause evident morphological and functional damage to the electroporated muscle.
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17
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Ojeda J, Bermedo-García F, Pérez V, Mella J, Hanna P, Herzberg D, Tejero R, López-Manzaneda M, Tabares L, Henríquez JP. The Mouse Levator Auris Longus Muscle: An Amenable Model System to Study the Role of Postsynaptic Proteins to the Maintenance and Regeneration of the Neuromuscular Synapse. Front Cell Neurosci 2020; 14:225. [PMID: 32848618 PMCID: PMC7405910 DOI: 10.3389/fncel.2020.00225] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 06/26/2020] [Indexed: 12/16/2022] Open
Abstract
The neuromuscular junction (NMJ) is the peripheral synapse that controls the coordinated movement of many organisms. The NMJ is also an archetypical model to study synaptic morphology and function. As the NMJ is the primary target of neuromuscular diseases and traumatic injuries, the establishment of suitable models to study the contribution of specific postsynaptic muscle-derived proteins on NMJ maintenance and regeneration is a permanent need. Considering the unique experimental advantages of the levator auris longus (LAL) muscle, here we present a method allowing for efficient electroporation-mediated gene transfer and subsequent detailed studies of the morphology and function of the NMJ and muscle fibers. Also, we have standardized efficient facial nerve injury protocols to analyze LAL muscle NMJ degeneration and regeneration. Our results show that the expression of a control fluorescent protein does not alter either the muscle structural organization, the apposition of the pre- and post-synaptic domains, or the functional neurotransmission parameters of the LAL muscle NMJs; in turn, the overexpression of MuSK, a major regulator of postsynaptic assembly, induces the formation of ectopic acetylcholine receptor clusters. Our NMJ denervation experiments showed complete reinnervation of LAL muscle NMJs four weeks after facial nerve injury. Together, these experimental strategies in the LAL muscle constitute effective methods to combine protein expression with accurate analyses at the levels of structure, function, and regeneration of the NMJ.
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Affiliation(s)
- Jorge Ojeda
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile.,Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain.,Developmental Neurobiology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Francisca Bermedo-García
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Viviana Pérez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Jessica Mella
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Patricia Hanna
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
| | - Daniel Herzberg
- Veterinary Sciences Clinic, Universidad de Concepción, Concepción, Chile
| | - Rocío Tejero
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Mario López-Manzaneda
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Lucia Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Juan Pablo Henríquez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA BioBio), Universidad de Concepción, Concepción, Chile
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18
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Sébastien M, Aubin P, Brocard J, Brocard J, Marty I, Fauré J. Dynamics of triadin, a muscle-specific triad protein, within sarcoplasmic reticulum subdomains. Mol Biol Cell 2020; 31:261-272. [PMID: 31877066 PMCID: PMC7183767 DOI: 10.1091/mbc.e19-07-0399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In skeletal muscle, proteins of the calcium release complex responsible for the excitation-contraction (EC) coupling are exclusively localized in specific reticulum–plasma membrane (ER-PM) contact points named triads. The CRC protein triadin (T95) is localized in the sarcoplasmic reticulum (SR) subdomain of triads where it forms large multimers. However, the mechanisms leading to the steady-state accumulation of T95 in these specific areas of SR are largely unknown. To visualize T95 dynamics, fluorescent chimeras were expressed in triadin knockout myotubes, and their mobility was compared with the mobility of Sec61β, a membrane protein of the SR unrelated to the EC coupling process. At all stages of skeletal muscle cells differentiation, we show a permanent flux of T95 diffusing in the SR membrane. Moreover, we find evidence that a longer residence time in the ER-PM contact point is due to the transmembrane domain of T95 resulting in an overall triad localization.
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Affiliation(s)
- Muriel Sébastien
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Perrine Aubin
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Jacques Brocard
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Julie Brocard
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Isabelle Marty
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Julien Fauré
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France.,Grenoble Institut Neurosciences, Inserm, U1216, CHU Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
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Expression and functional analysis of the hydrogen peroxide biosensors HyPer and HyPer2 in C2C12 myoblasts/myotubes and single skeletal muscle fibres. Sci Rep 2020; 10:871. [PMID: 31965006 PMCID: PMC6972731 DOI: 10.1038/s41598-020-57821-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/06/2020] [Indexed: 01/11/2023] Open
Abstract
Hydrogen peroxide (H2O2) is generated in cells and plays an important role as a signalling molecule. It has been reported that H2O2 is involved in physiological and pathological processes in skeletal muscle. However, H2O2 detection in cells with traditional techniques produces frequent artefacts. Currently, the HyPer biosensor detects intracellular H2O2 specifically in real time using fluorescence microscopy. The aim of this study was to develop and optimize approaches used to express the HyPer biosensor in different models of skeletal muscle cells, such as the C2C12 myoblast/myotube cell line and mature skeletal muscle fibres isolated from C57BL/6J mice, and to measure intracellular H2O2 in real time in these cells. The results show that the expression of the HyPer biosensor in skeletal muscle cells is possible. In addition, we demonstrate that HyPer is functional and that this biosensor detects changes and fluctuations in intracellular H2O2 in a reversible manner. The HyPer2 biosensor, which is a more advanced version of HyPer, presents improved properties in terms of sensitivity in detecting lower concentrations of H2O2 in skeletal muscle fibres. In conclusion, the expression of the HyPer biosensor in the different experimental models combined with fluorescence microscopy techniques is a powerful methodology to monitor and register intracellular H2O2 specifically in skeletal muscle. The innovation of the methodological approaches presented in this study may present new avenues for studying the role of H2O2 in skeletal muscle pathophysiology. Furthermore, the methodology may potentially be adapted to yield other specific biosensors for different reactive oxygen and nitrogen species or metabolites involved in cellular functions.
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Demonbreun AR, Fallon KS, Oosterbaan CC, Bogdanovic E, Warner JL, Sell JJ, Page PG, Quattrocelli M, Barefield DY, McNally EM. Recombinant annexin A6 promotes membrane repair and protects against muscle injury. J Clin Invest 2019; 129:4657-4670. [PMID: 31545299 PMCID: PMC6819108 DOI: 10.1172/jci128840] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/26/2019] [Indexed: 12/22/2022] Open
Abstract
Membrane repair is essential to cell survival. In skeletal muscle, injury often associates with plasma membrane disruption. Additionally, muscular dystrophy is linked to mutations in genes that produce fragile membranes or reduce membrane repair. Methods to enhance repair and reduce susceptibility to injury could benefit muscle in both acute and chronic injury settings. Annexins are a family of membrane-associated Ca2+-binding proteins implicated in repair, and annexin A6 was previously identified as a genetic modifier of muscle injury and disease. Annexin A6 forms the repair cap over the site of membrane disruption. To elucidate how annexins facilitate repair, we visualized annexin cap formation during injury. We found that annexin cap size positively correlated with increasing Ca2+ concentrations. We also found that annexin overexpression promoted external blebs enriched in Ca2+ and correlated with a reduction of intracellular Ca2+ at the injury site. Annexin A6 overexpression reduced membrane injury, consistent with enhanced repair. Treatment with recombinant annexin A6 protected against acute muscle injury in vitro and in vivo. Moreover, administration of recombinant annexin A6 in a model of muscular dystrophy reduced serum creatinine kinase, a biomarker of disease. These data identify annexins as mediators of membrane-associated Ca2+ release during membrane repair and annexin A6 as a therapeutic target to enhance membrane repair capacity.
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Affiliation(s)
- Alexis R. Demonbreun
- Center for Genetic Medicine, and
- Department of Pharmacology, Northwestern University, Chicago, Illinois, USA
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Tran MP, Tsutsumi R, Erberich JM, Chen KD, Flores MD, Cooper KL. Evolutionary loss of foot muscle during development with characteristics of atrophy and no evidence of cell death. eLife 2019; 8:50645. [PMID: 31612857 PMCID: PMC6855805 DOI: 10.7554/elife.50645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 10/01/2019] [Indexed: 12/19/2022] Open
Abstract
Many species that run or leap across sparsely vegetated habitats, including horses and deer, evolved the severe reduction or complete loss of foot muscles as skeletal elements elongated and digits were lost, and yet the developmental mechanisms remain unknown. Here, we report the natural loss of foot muscles in the bipedal jerboa, Jaculus jaculus. Although adults have no muscles in their feet, newborn animals have muscles that rapidly disappear soon after birth. We were surprised to find no evidence of apoptotic or necrotic cell death during stages of peak myofiber loss, countering well-supported assumptions of developmental tissue remodeling. We instead see hallmarks of muscle atrophy, including an ordered disassembly of the sarcomere associated with upregulation of the E3 ubiquitin ligases, MuRF1 and Atrogin-1. We propose that the natural loss of muscle, which remodeled foot anatomy during evolution and development, involves cellular mechanisms that are typically associated with disease or injury. Intrinsic muscles are a group of muscles deep inside the hands and feet. They help to control the precise movements required, for example, for a pianist to play their instrument or for certain animals to climb with remarkable agility. Some animals, such as horses and deer, have evolved in such a way that they no longer grasp objects with hands and feet. Where intrinsic muscles were once present in the hands and feet of their ancestors, these animals now have strong ligaments that prevent over-extension of the wrist and ankle joints during hard landings. Given their size, it is difficult to study horses and deer in the laboratory and understand how they lost their intrinsic muscles during evolution. Tran et al. therefore focused on a small rodent called the lesser Egyptian jerboa, which also displays long legs with strong ligaments and no intrinsic muscles. Newborn jerboas have foot muscles that look very much like the intrinsic muscles found in mice, but these muscles disappear within 4 days of birth. A mechanism called programmed cell death is often responsible for specific tissues disappearing during development, but the experiments of Tran et al. revealed that this was not the case in jerboas. Instead, their intrinsic muscles were degraded by processes triggered by genes that disassemble underused muscles. In mice and humans, fasting, nerve injuries, or immobility trigger this type of muscle degradation, but in jerboas these processes appear to be a normal part of development. This unexpected discovery shows that development and disease-like processes are linked, and that more studies of nontraditional research animals may help scientists better understand these connections.
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Affiliation(s)
- Mai P Tran
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California, San Diego, La Jolla, United States
| | - Rio Tsutsumi
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California, San Diego, La Jolla, United States
| | - Joel M Erberich
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California, San Diego, La Jolla, United States
| | - Kevin D Chen
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California, San Diego, La Jolla, United States
| | - Michelle D Flores
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California, San Diego, La Jolla, United States
| | - Kimberly L Cooper
- Division of Biological Sciences, Section of Cellular and Developmental Biology, University of California, San Diego, La Jolla, United States
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22
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Young CS, Mokhonova E, Quinonez M, Pyle AD, Spencer MJ. Creation of a Novel Humanized Dystrophic Mouse Model of Duchenne Muscular Dystrophy and Application of a CRISPR/Cas9 Gene Editing Therapy. J Neuromuscul Dis 2019; 4:139-145. [PMID: 28505980 PMCID: PMC5565771 DOI: 10.3233/jnd-170218] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Duchenne muscular dystrophy is caused by mutations in DMD which disrupt the reading frame. Therapeutic strategies that restore DMD's reading frame, such as exon skipping and CRISPR/Cas9, need to be tested in the context of the human DMD sequence in vivo. We have developed a novel dystrophic mouse model by using CRISPR/Cas9 to delete exon 45 in the human DMD gene in hDMD mice, which places DMD out-of-frame. We have utilized this model to demonstrate that our clinically-relevant CRISPR/Cas9 platform, which targets deletion of human DMD exons 45-55, can be directly applied in vivo to restore dystrophin.
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Affiliation(s)
- Courtney S. Young
- Molecular Biology Interdepartmental Program, University of California, Los Angeles, CA, USA
- Center for Duchenne Muscular Dystrophy at UCLA, University of California, Los Angeles, CA, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, USA
| | - Ekaterina Mokhonova
- Center for Duchenne Muscular Dystrophy at UCLA, University of California, Los Angeles, CA, USA
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Marbella Quinonez
- Center for Duchenne Muscular Dystrophy at UCLA, University of California, Los Angeles, CA, USA
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - April D. Pyle
- Center for Duchenne Muscular Dystrophy at UCLA, University of California, Los Angeles, CA, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, USA
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Melissa J. Spencer
- Molecular Biology Interdepartmental Program, University of California, Los Angeles, CA, USA
- Center for Duchenne Muscular Dystrophy at UCLA, University of California, Los Angeles, CA, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, USA
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
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23
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Randazzo D, Khalique U, Belanto JJ, Kenea A, Talsness DM, Olthoff JT, Tran MD, Zaal KJ, Pak K, Pinal-Fernandez I, Mammen AL, Sackett D, Ervasti JM, Ralston E. Persistent upregulation of the β-tubulin tubb6, linked to muscle regeneration, is a source of microtubule disorganization in dystrophic muscle. Hum Mol Genet 2019; 28:1117-1135. [PMID: 30535187 DOI: 10.1093/hmg/ddy418] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/26/2018] [Accepted: 12/02/2018] [Indexed: 12/20/2022] Open
Abstract
In healthy adult skeletal muscle fibers microtubules form a three-dimensional grid-like network. In the mdx mouse, a model of Duchenne muscular dystrophy (DMD), microtubules are mostly disordered, without periodicity. These microtubule defects have been linked to the mdx mouse pathology. We now report that increased expression of the beta 6 class V β-tubulin (tubb6) contributes to the microtubule changes of mdx muscles. Wild-type muscle fibers overexpressing green fluorescent protein (GFP)-tubb6 (but not GFP-tubb5) have disorganized microtubules whereas mdx muscle fibers depleted of tubb6 (but not of tubb5) normalize their microtubules, suggesting that increasing tubb6 is toxic. However, tubb6 increases spontaneously during differentiation of mouse and human muscle cultures. Furthermore, endogenous tubb6 is not uniformly expressed in mdx muscles but is selectively increased in fiber clusters, which we identify as regenerating. Similarly, mdx-based rescued transgenic mice that retain a higher than expected tubb6 level show focal expression of tubb6 in subsets of fibers. Tubb6 is also upregulated in cardiotoxin-induced mouse muscle regeneration, in human myositis and DMD biopsies, and the tubb6 level correlates with that of embryonic myosin heavy chain, a regeneration marker. In conclusion, modulation of a β-tubulin isotype plays a role in muscle differentiation and regeneration. Increased tubb6 expression and microtubule reorganization are not pathological per se but reflect a return to an earlier developmental stage. However, chronic elevation of tubb6, as occurs in the mdx mouse, may contribute to the repeated cycles of regeneration and to the pathology of the disease.
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Affiliation(s)
- Davide Randazzo
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Umara Khalique
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Joseph J Belanto
- Department of Biochemistry, Molecular Biology, and Biophysics, and Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - Aster Kenea
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Dana M Talsness
- Department of Biochemistry, Molecular Biology, and Biophysics, and Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - John T Olthoff
- Department of Biochemistry, Molecular Biology, and Biophysics, and Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - Michelle D Tran
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Kristien J Zaal
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Katherine Pak
- Laboratory of Muscle Stem Cells and Gene Regulation, Muscle Disease Unit, NIAMS, NIH, Bethesda, MD, USA
| | - Iago Pinal-Fernandez
- Laboratory of Muscle Stem Cells and Gene Regulation, Muscle Disease Unit, NIAMS, NIH, Bethesda, MD, USA.,Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Andrew L Mammen
- Laboratory of Muscle Stem Cells and Gene Regulation, Muscle Disease Unit, NIAMS, NIH, Bethesda, MD, USA.,Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dan Sackett
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology, and Biophysics, and Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - Evelyn Ralston
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
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24
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Sokołowska E, Błachnio-Zabielska AU. A Critical Review of Electroporation as A Plasmid Delivery System in Mouse Skeletal Muscle. Int J Mol Sci 2019; 20:ijms20112776. [PMID: 31174257 PMCID: PMC6600476 DOI: 10.3390/ijms20112776] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
The gene delivery to skeletal muscles is a promising strategy for the treatment of both muscular disorders (by silencing or overexpression of specific gene) and systemic secretion of therapeutic proteins. The use of a physical method like electroporation with plate or needle electrodes facilitates long-lasting gene silencing in situ. It has been reported that electroporation enhances the expression of the naked DNA gene in the skeletal muscle up to 100 times and decreases the changeability of the intramuscular expression. Coelectransfer of reporter genes such as green fluorescent protein (GFP), luciferase or beta-galactosidase allows the observation of correctly performed silencing in the muscles. Appropriate selection of plasmid injection volume and concentration, as well as electrotransfer parameters, such as the voltage, the length and the number of electrical pulses do not cause long-term damage to myocytes. In this review, we summarized the electroporation methodology as well as the procedure of electrotransfer to the gastrocnemius, tibialis, soleus and foot muscles and compare their advantages and disadvantages.
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Affiliation(s)
- Emilia Sokołowska
- Department of Hygiene, Epidemiology and Metabolic Disorders, Medical University of Bialystok, 15-222 Bialystok, Poland.
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25
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Valladares D, Utreras-Mendoza Y, Campos C, Morales C, Diaz-Vegas A, Contreras-Ferrat A, Westermeier F, Jaimovich E, Marchi S, Pinton P, Lavandero S. IP 3 receptor blockade restores autophagy and mitochondrial function in skeletal muscle fibers of dystrophic mice. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3685-3695. [PMID: 30251688 DOI: 10.1016/j.bbadis.2018.08.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 08/06/2018] [Accepted: 08/30/2018] [Indexed: 12/14/2022]
Abstract
Duchenne muscular dystrophy (DMD) is characterized by a severe and progressive destruction of muscle fibers associated with altered Ca2+ homeostasis. We have previously shown that the IP3 receptor (IP3R) plays a role in elevating basal cytoplasmic Ca2+ and that pharmacological blockade of IP3R restores muscle function. Moreover, we have shown that the IP3R pathway negatively regulates autophagy by controlling mitochondrial Ca2+ levels. Nevertheless, it remains unclear whether IP3R is involved in abnormal mitochondrial Ca2+ levels, mitochondrial dynamics, or autophagy and mitophagy observed in adult DMD skeletal muscle. Here, we show that the elevated basal autophagy and autophagic flux levels were normalized when IP3R was downregulated in mdx fibers. Pharmacological blockade of IP3R in mdx fibers restored both increased mitochondrial Ca2+ levels and mitochondrial membrane potential under resting conditions. Interestingly, mdx mitochondria changed from a fission to an elongated state after IP3R knockdown, and the elevated mitophagy levels in mdx fibers were normalized. To our knowledge, this is the first study associating IP3R1 activity with changes in autophagy, mitochondrial Ca2+ levels, mitochondrial membrane potential, mitochondrial dynamics, and mitophagy in adult mouse skeletal muscle. Moreover, these results suggest that increased IP3R activity in mdx fibers plays an important role in the pathophysiology of DMD. Overall, these results lead us to propose the use of specific IP3R blockers as a new pharmacological treatment for DMD, given their ability to restore both autophagy/mitophagy and mitochondrial function.
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Affiliation(s)
- Denisse Valladares
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Escuela de Kinesiologia, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile.
| | - Yildy Utreras-Mendoza
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Cristian Campos
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Camilo Morales
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Alexis Diaz-Vegas
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Ariel Contreras-Ferrat
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Francisco Westermeier
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Enrique Jaimovich
- Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Chile
| | - Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Center for Studies of Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile; Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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26
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Melzer W. No voltage change at skeletal muscle SR membrane during Ca 2+ release-just Mermaids on acid. J Gen Physiol 2018; 150:1055-1058. [PMID: 29970411 PMCID: PMC6080887 DOI: 10.1085/jgp.201812084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Melzer highlights new work confirming that the sarcoplasmic reticulum transmembrane voltage changes little during Ca2+ release Calcium ions control multiple physiological functions by binding to extracellular and intracellular targets. One of the best-studied Ca2+-dependent functions is contraction of smooth and striated muscle tissue, which results from Ca2+ ligation to calmodulin and troponin C, respectively. Ca2+ signaling typically involves flux of the ion across membranes via specifically gated channel proteins. Because calcium ions are charged, they possess the ability to generate changes in the respective transmembrane voltage. Ca2+-dependent voltage alterations of the surface membrane are easily measured using microelectrodes. A well-known example is the characteristic plateau phase of the action potential in cardiac ventricular cells that results from the opening of voltage-gated L-type Ca2+ channels. Ca2+ ions are also released from intracellular storage compartments in many cells, but these membranes are not accessible to direct voltage recording with microelectrodes. In muscle, for example, release of Ca2+ from the sarcoplasmic reticulum (SR) to the myoplasm constitutes a flux that is considerably larger than the entry flux from the extracellular space. Whether this flux is accompanied by a voltage change across the SR membrane is an obvious question of mechanistic importance and has been the subject of many investigations. Because the tiny spaces enclosed by the SR membrane are inaccessible to microelectrodes, alternative methods have to be applied. In a study by Sanchez et al. (2018. J. Gen. Physiol.https://doi.org/10.1085/jgp.201812035) in this issue, modern confocal light microscopy and genetically encoded voltage probes targeted to the SR were applied in a new approach to search for changes in the membrane potential of the SR during Ca2+ release.
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Affiliation(s)
- Werner Melzer
- Institut für Angewandte Physiologie, Universität Ulm, Ulm, Germany
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27
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Ross BL, Tenner B, Markwardt ML, Zviman A, Shi G, Kerr JP, Snell NE, McFarland JJ, Mauban JR, Ward CW, Rizzo MA, Zhang J. Single-color, ratiometric biosensors for detecting signaling activities in live cells. eLife 2018; 7:e35458. [PMID: 29968564 PMCID: PMC6037473 DOI: 10.7554/elife.35458] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/16/2018] [Indexed: 11/22/2022] Open
Abstract
Genetically encoded fluorescent biosensors have revolutionized the study of signal transduction by enabling the real-time tracking of signaling activities in live cells. Investigating the interaction between signaling networks has become increasingly important to understanding complex cellular phenomena, necessitating an update of the biosensor toolkit to allow monitoring and perturbing multiple activities simultaneously in the same cell. We therefore developed a new class of fluorescent biosensors based on homo-FRET, deemed FLuorescence Anisotropy REporters (FLAREs), which combine the multiplexing ability of single-color sensors with a quantitative, ratiometric readout. Using an array of color variants, we were able to demonstrate multiplexed imaging of three activity reporters simultaneously in the same cell. We further demonstrate the compatibility of FLAREs for use with optogenetic tools as well as intravital two-photon imaging.
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Affiliation(s)
- Brian L Ross
- Department of PharmacologyUniversity of California, San DiegoSan DiegoUnited States
- Department of Biomedical EngineeringJohns Hopkins UniversityBaltimoreUnited States
| | - Brian Tenner
- Department of PharmacologyUniversity of California, San DiegoSan DiegoUnited States
- Program in Molecular BiophysicsJohns Hopkins University School of MedicineBaltimoreUnited States
| | - Michele L Markwardt
- Department of PhysiologyUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Adam Zviman
- Department of PhysiologyUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Guoli Shi
- Department of OrthopaedicsUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Jaclyn P Kerr
- Department of OrthopaedicsUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Nicole E Snell
- Department of PhysiologyUniversity of Maryland BaltimoreBaltimoreUnited States
| | | | - Joseph R Mauban
- Department of PhysiologyUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Christopher W Ward
- Department of OrthopaedicsUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Megan A Rizzo
- Department of PhysiologyUniversity of Maryland BaltimoreBaltimoreUnited States
| | - Jin Zhang
- Department of PharmacologyUniversity of California, San DiegoSan DiegoUnited States
- Program in Molecular BiophysicsJohns Hopkins University School of MedicineBaltimoreUnited States
- Department of Pharmacology and Molecular SciencesJohns Hopkins University School of MedicineBaltimoreUnited States
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28
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Madsen AB, Knudsen JR, Henriquez-Olguin C, Angin Y, Zaal KJ, Sylow L, Schjerling P, Ralston E, Jensen TE. β-Actin shows limited mobility and is required only for supraphysiological insulin-stimulated glucose transport in young adult soleus muscle. Am J Physiol Endocrinol Metab 2018; 315. [PMID: 29533739 PMCID: PMC6087721 DOI: 10.1152/ajpendo.00392.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Studies in skeletal muscle cell cultures suggest that the cortical actin cytoskeleton is a major requirement for insulin-stimulated glucose transport, implicating the β-actin isoform, which in many cell types is the main actin isoform. However, it is not clear that β-actin plays such a role in mature skeletal muscle. Neither dependency of glucose transport on β-actin nor actin reorganization upon glucose transport have been tested in mature muscle. To investigate the role of β-actin in fully differentiated muscle, we performed a detailed characterization of wild type and muscle-specific β-actin knockout (KO) mice. The effects of the β-actin KO were subtle; however, we confirmed the previously reported decline in running performance of β-actin KO mice compared with wild type during repeated maximal running tests. We also found insulin-stimulated glucose transport into incubated muscles reduced in soleus but not in extensor digitorum longus muscle of young adult mice. Contraction-stimulated glucose transport trended toward the same pattern, but the glucose transport phenotype disappeared in soleus muscles from mature adult mice. No genotype-related differences were found in body composition or glucose tolerance or by indirect calorimetry measurements. To evaluate β-actin mobility in mature muscle, we electroporated green fluorescent protein (GFP)-β-actin into flexor digitorum brevis muscle fibers and measured fluorescence recovery after photobleaching. GFP-β-actin showed limited unstimulated mobility and no changes after insulin stimulation. In conclusion, β-actin is not required for glucose transport regulation in mature mouse muscle under the majority of the tested conditions. Thus, our work reveals fundamental differences in the role of the cortical β-actin cytoskeleton in mature muscle compared with cell culture.
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Affiliation(s)
- Agnete B Madsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Jonas R Knudsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Carlos Henriquez-Olguin
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
- Centro de Estudios Moleculares de la Célula, Instituto de Ciencias Biomédicas, Universidad de Chile ; Laboratory of Exercise Sciences, Clínica MEDS, Santiago , Chile
| | - Yeliz Angin
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Kristien J Zaal
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health , Bethesda, Maryland
| | - Lykke Sylow
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery, Bispebjerg Hospital , Copenhagen , Denmark
- Center of Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Evelyn Ralston
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health , Bethesda, Maryland
| | - Thomas E Jensen
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
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29
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Díaz-Vegas AR, Cordova A, Valladares D, Llanos P, Hidalgo C, Gherardi G, De Stefani D, Mammucari C, Rizzuto R, Contreras-Ferrat A, Jaimovich E. Mitochondrial Calcium Increase Induced by RyR1 and IP3R Channel Activation After Membrane Depolarization Regulates Skeletal Muscle Metabolism. Front Physiol 2018; 9:791. [PMID: 29988564 PMCID: PMC6026899 DOI: 10.3389/fphys.2018.00791] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/06/2018] [Indexed: 11/13/2022] Open
Abstract
Aim: We hypothesize that both type-1 ryanodine receptor (RyR1) and IP3-receptor (IP3R) calcium channels are necessary for the mitochondrial Ca2+ increase caused by membrane depolarization induced by potassium (or by electrical stimulation) of single skeletal muscle fibers; this calcium increase would couple muscle fiber excitation to an increase in metabolic output from mitochondria (excitation-metabolism coupling). Methods: Mitochondria matrix and cytoplasmic Ca2+ levels were evaluated in fibers isolated from flexor digitorium brevis muscle using plasmids for the expression of a mitochondrial Ca2+ sensor (CEPIA3mt) or a cytoplasmic Ca2+ sensor (RCaMP). The role of intracellular Ca2+ channels was evaluated using both specific pharmacological inhibitors (xestospongin B for IP3R and Dantrolene for RyR1) and a genetic approach (shIP3R1-RFP). O2 consumption was detected using Seahorse Extracellular Flux Analyzer. Results: In isolated muscle fibers cell membrane depolarization increased both cytoplasmic and mitochondrial Ca2+ levels. Mitochondrial Ca2+ uptake required functional inositol IP3R and RyR1 channels. Inhibition of either channel decreased basal O2 consumption rate but only RyR1 inhibition decreased ATP-linked O2 consumption. Cell membrane depolarization-induced Ca2+ signals in sub-sarcolemmal mitochondria were accompanied by a reduction in mitochondrial membrane potential; Ca2+ signals propagated toward intermyofibrillar mitochondria, which displayed increased membrane potential. These results are compatible with slow, Ca2+-dependent propagation of mitochondrial membrane potential from the surface toward the center of the fiber. Conclusion: Ca2+-dependent changes in mitochondrial membrane potential have different kinetics in the surface vs. the center of the fiber; these differences are likely to play a critical role in the control of mitochondrial metabolism, both at rest and after membrane depolarization as part of an “excitation-metabolism” coupling process in skeletal muscle fibers.
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Affiliation(s)
- Alexis R Díaz-Vegas
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Alex Cordova
- Biomedical Neuroscience Institute, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Denisse Valladares
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Exercise and Movement Science Laboratory, Universidad Finis Terrae, Santiago, Chile
| | - Paola Llanos
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Institute for Research in Dental Science, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ariel Contreras-Ferrat
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
| | - Enrique Jaimovich
- Muscle Physiology Laboratory, Center of Studies in Exercise, Metabolism and Cancer, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile
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TRPV1 variants impair intracellular Ca 2+ signaling and may confer susceptibility to malignant hyperthermia. Genet Med 2018; 21:441-450. [PMID: 29930394 PMCID: PMC6752298 DOI: 10.1038/s41436-018-0066-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/04/2018] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Malignant hyperthermia (MH) is a pharmacogenetic disorder arising from uncontrolled muscle calcium release due to an abnormality in the sarcoplasmic reticulum (SR) calcium-release mechanism triggered by halogenated inhalational anesthetics. However, the molecular mechanisms involved are still incomplete. METHODS We aimed to identify transient receptor potential vanilloid 1 (TRPV1) variants within the entire coding sequence in patients who developed sensitivity to MH of unknown etiology. In vitro and in vivo functional studies were performed in heterologous expression system, trpv1-/- mice, and a murine model of human MH. RESULTS We identified TRPV1 variants in two patients and their heterologous expression in muscles of trpv1-/- mice strongly enhanced calcium release from SR upon halogenated anesthetic stimulation, suggesting they could be responsible for the MH phenotype. We confirmed the in vivo significance by using mice with a knock-in mutation (Y524S) in the type I ryanodine receptor (Ryr1), a mutation analogous to the Y522S mutation associated with MH in humans. We showed that the TRPV1 antagonist capsazepine slows the heat-induced hypermetabolic response in this model. CONCLUSION We propose that TRPV1 contributes to MH and could represent an actionable therapeutic target for prevention of the pathology and also be responsible for MH sensitivity when mutated.
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31
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Lim JA, Sun B, Puertollano R, Raben N. Therapeutic Benefit of Autophagy Modulation in Pompe Disease. Mol Ther 2018; 26:1783-1796. [PMID: 29804932 DOI: 10.1016/j.ymthe.2018.04.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 12/11/2022] Open
Abstract
The complexity of the pathogenic cascade in lysosomal storage disorders suggests that combination therapy will be needed to target various aspects of pathogenesis. The standard of care for Pompe disease (glycogen storage disease type II), a deficiency of lysosomal acid alpha glucosidase, is enzyme replacement therapy (ERT). Many patients have poor outcomes due to limited efficacy of the drug in clearing muscle glycogen stores. The resistance to therapy is linked to massive autophagic buildup in the diseased muscle. We have explored two strategies to address the problem. Genetic suppression of autophagy in muscle of knockout mice resulted in the removal of autophagic buildup, increase in muscle force, decrease in glycogen level, and near-complete clearance of lysosomal glycogen following ERT. However, this approach leads to accumulation of ubiquitinated proteins, oxidative stress, and exacerbation of muscle atrophy. Another approach involves AAV-mediated TSC knockdown in knockout muscle leading to upregulation of mTOR, inhibition of autophagy, reversal of atrophy, and efficient cellular clearance on ERT. Importantly, this approach reveals the possibility of reversing already established autophagic buildup, rather than preventing its development.
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Affiliation(s)
- Jeong-A Lim
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA; Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Baodong Sun
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Rosa Puertollano
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
| | - Nina Raben
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
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32
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Tarpey MD, Amorese AJ, Balestrieri NP, Ryan TE, Schmidt CA, McClung JM, Spangenburg EE. Characterization and utilization of the flexor digitorum brevis for assessing skeletal muscle function. Skelet Muscle 2018; 8:14. [PMID: 29665848 PMCID: PMC5905177 DOI: 10.1186/s13395-018-0160-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/03/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The ability to assess skeletal muscle function and delineate regulatory mechanisms is essential to uncovering therapeutic approaches that preserve functional independence in a disease state. Skeletal muscle provides distinct experimental challenges due to inherent differences across muscle groups, including fiber type and size that may limit experimental approaches. The flexor digitorum brevis (FDB) possesses numerous properties that offer the investigator a high degree of experimental flexibility to address specific hypotheses. To date, surprisingly few studies have taken advantage of the FDB to investigate mechanisms regulating skeletal muscle function. The purpose of this study was to characterize and experimentally demonstrate the value of the FDB muscle for scientific investigations. METHODS First, we characterized the FDB phenotype and provide reference comparisons to skeletal muscles commonly used in the field. We developed approaches allowing for experimental assessment of force production, in vitro and in vivo microscopy, and mitochondrial respiration to demonstrate the versatility of the FDB. As proof-of principle, we performed experiments to alter force production or mitochondrial respiration to validate the flexibility the FDB affords the investigator. RESULTS The FDB is made up of small predominantly type IIa and IIx fibers that collectively produce less peak isometric force than the extensor digitorum longus (EDL) or soleus muscles, but demonstrates a greater fatigue resistance than the EDL. Unlike the other muscles, inherent properties of the FDB muscle make it amenable to multiple in vitro- and in vivo-based microscopy methods. Due to its anatomical location, the FDB can be used in cardiotoxin-induced muscle injury protocols and is amenable to electroporation of cDNA with a high degree of efficiency allowing for an effective means of genetic manipulation. Using a novel approach, we also demonstrate methods for assessing mitochondrial respiration in the FDB, which are comparable to the commonly used gastrocnemius muscle. As proof of principle, short-term overexpression of Pgc1α in the FDB increased mitochondrial respiration rates. CONCLUSION The results highlight the experimental flexibility afforded the investigator by using the FDB muscle to assess mechanisms that regulate skeletal muscle function.
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Affiliation(s)
- Michael D. Tarpey
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Adam J. Amorese
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Nicholas P. Balestrieri
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Terence E. Ryan
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Cameron A. Schmidt
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Joseph M. McClung
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834 USA
| | - Espen E. Spangenburg
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834 USA
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33
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Jackson KC, Tarpey MD, Valencia AP, Iñigo MR, Pratt SJ, Patteson DJ, McClung JM, Lovering RM, Thomson DM, Spangenburg EE. Induced Cre-mediated knockdown of Brca1 in skeletal muscle reduces mitochondrial respiration and prevents glucose intolerance in adult mice on a high-fat diet. FASEB J 2018; 32:3070-3084. [PMID: 29401626 DOI: 10.1096/fj.201700464r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The breast cancer type 1 susceptibility protein (Brca1) is a regulator of DNA repair in mammary gland cells; however, recent cell culture evidence suggests that Brca1 influences other processes, including those in nonmammary cells. In this study, we sought to determine whether Brca1 is necessary for metabolic regulation of skeletal muscle using a novel in vivo mouse model. We developed an inducible skeletal muscle-specific Brca1knockout (BRCA1KOsmi) model to test whether Brca1 expression is necessary for maintenance of metabolic function of skeletal muscle when exposed to a high-fat diet (HFD). Our data demonstrated that deletion of Brca1 prevented HFD-induced alterations in glucose and insulin tolerance. Irrespective of diet, BRCA1KOsmi mice exhibited significantly lower ADP-stimulated complex I mitochondrial respiration rates compared to age-matched wild-type (WT) mice. The data show that Brca1 has the ability to localize to the mitochondria in skeletal muscle and that BRCA1KOsmi mice exhibit higher whole-body CO2 production, respiratory exchange ratio, and energy expenditure, compared with the WT mice. Our results demonstrate that loss of Brca1 in skeletal muscle leads to dysregulated metabolic function, characterized by decreased mitochondrial respiration. Thus, any condition that results in loss of Brca1 function could induce metabolic imbalance in skeletal muscle.-Jackson, K. C., Tarpey, M. D., Valencia, A. P., Iñigo, M. R., Pratt, S. J., Patteson, D. J., McClung, J. M., Lovering, R. M., Thomson, D. M., Spangenburg, E. E. Induced Cre-mediated knockdown of Brca1 in skeletal muscle reduces mitochondrial respiration and prevents glucose intolerance in adult mice on a high-fat diet.
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Affiliation(s)
- Kathryn C Jackson
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA
| | - Michael D Tarpey
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ana P Valencia
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA
| | - Melissa R Iñigo
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA.,Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Stephen J Pratt
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Daniel J Patteson
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Joseph M McClung
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; and
| | - Richard M Lovering
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - David M Thomson
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA
| | - Espen E Spangenburg
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA.,Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; and
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34
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Oh J, Sinha I, Tan KY, Rosner B, Dreyfuss JM, Gjata O, Tran P, Shoelson SE, Wagers AJ. Age-associated NF-κB signaling in myofibers alters the satellite cell niche and re-strains muscle stem cell function. Aging (Albany NY) 2017; 8:2871-2896. [PMID: 27852976 PMCID: PMC5191876 DOI: 10.18632/aging.101098] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 10/25/2016] [Indexed: 12/23/2022]
Abstract
Skeletal muscle is a highly regenerative tissue, but muscle repair potential is increasingly compromised with advancing age. In this study, we demonstrate that increased NF-κB activity in aged muscle fibers contributes to diminished myogenic potential of their associated satellite cells. We further examine the impact of genetic modulation of NF-κB signaling in muscle satellite cells or myofibers on recovery after damage. These studies reveal that NF-κB activity in differentiated myofibers is sufficient to drive dysfunction of muscle regenerative cells via cell-non-autonomous mechanisms. Inhibition of NF-κB, or its downstream target Phospholipase A2, in myofibers rescued muscle regenerative potential in aged muscle. Moreover, systemic administration of sodium salicylate, an FDA-approved NF-κB inhibitor, decreased inflammatory gene expression and improved repair in aged muscle. Together, these studies identify a unique NF-κB regulated, non-cell autonomous mechanism by which stem cell function is linked to lipid signaling and homeostasis, and provide important new targets to stimulate muscle repair in aged individuals.
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Affiliation(s)
- Juhyun Oh
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Cambridge, MA 02138, USA.,Joslin Diabetes Center, Boston, MA 02215, USA.,Paul F. Glenn Center for the Biology of Aging, Harvard Medical School, Boston, MA 02115, USA
| | - Indranil Sinha
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Cambridge, MA 02138, USA.,Joslin Diabetes Center, Boston, MA 02215, USA.,Division of Plastic Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Kah Yong Tan
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Cambridge, MA 02138, USA.,Joslin Diabetes Center, Boston, MA 02215, USA
| | - Bernard Rosner
- Department of Biostatistics, Harvard School of Public Health, MA 02115, USA
| | - Jonathan M Dreyfuss
- Joslin Diabetes Center, Boston, MA 02215, USA.,Department of Biomedical Engineering, Boston University, Boston 02215, USA
| | - Ornela Gjata
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Peter Tran
- Joslin Diabetes Center, Boston, MA 02215, USA
| | - Steven E Shoelson
- Joslin Diabetes Center, Boston, MA 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Amy J Wagers
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Cambridge, MA 02138, USA.,Joslin Diabetes Center, Boston, MA 02215, USA.,Paul F. Glenn Center for the Biology of Aging, Harvard Medical School, Boston, MA 02115, USA
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35
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Quattrocelli M, Capote J, Ohiri JC, Warner JL, Vo AH, Earley JU, Hadhazy M, Demonbreun AR, Spencer MJ, McNally EM. Genetic modifiers of muscular dystrophy act on sarcolemmal resealing and recovery from injury. PLoS Genet 2017; 13:e1007070. [PMID: 29065150 PMCID: PMC5669489 DOI: 10.1371/journal.pgen.1007070] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/03/2017] [Accepted: 10/11/2017] [Indexed: 12/17/2022] Open
Abstract
Genetic disruption of the dystrophin complex produces muscular dystrophy characterized by a fragile muscle plasma membrane leading to excessive muscle degeneration. Two genetic modifiers of Duchenne Muscular Dystrophy implicate the transforming growth factor β (TGFβ) pathway, osteopontin encoded by the SPP1 gene and latent TGFβ binding protein 4 (LTBP4). We now evaluated the functional effect of these modifiers in the context of muscle injury and repair to elucidate their mechanisms of action. We found that excess osteopontin exacerbated sarcolemmal injury, and correspondingly, that loss of osteopontin reduced injury extent both in isolated myofibers and in muscle in vivo. We found that ablation of osteopontin was associated with reduced expression of TGFβ and TGFβ-associated pathways. We identified that increased TGFβ resulted in reduced expression of Anxa1 and Anxa6, genes encoding key components of the muscle sarcolemma resealing process. Genetic manipulation of Ltbp4 in dystrophic muscle also directly modulated sarcolemmal resealing, and Ltbp4 alleles acted in concert with Anxa6, a distinct modifier of muscular dystrophy. These data provide a model in which a feed forward loop of TGFβ and osteopontin directly impacts the capacity of muscle to recover from injury, and identifies an intersection of genetic modifiers on muscular dystrophy.
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MESH Headings
- Animals
- Annexin A1/genetics
- Annexin A1/metabolism
- Annexin A6/genetics
- Annexin A6/metabolism
- Female
- Gene Expression Regulation
- Genes, Modifier
- Latent TGF-beta Binding Proteins/physiology
- Male
- Mice
- Mice, Inbred DBA
- Mice, Knockout
- Muscle, Skeletal/injuries
- Muscle, Skeletal/physiology
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/metabolism
- Muscular Dystrophy, Animal/pathology
- Osteopontin/genetics
- Osteopontin/metabolism
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Recovery of Function
- Sarcolemma/physiology
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Affiliation(s)
- Mattia Quattrocelli
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Joanna Capote
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Joyce C. Ohiri
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - James L. Warner
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Andy H. Vo
- Committee on Development, Regeneration, and Stem Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Judy U. Earley
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Michele Hadhazy
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Alexis R. Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Melissa J. Spencer
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
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36
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Laker RC, Drake JC, Wilson RJ, Lira VA, Lewellen BM, Ryall KA, Fisher CC, Zhang M, Saucerman JJ, Goodyear LJ, Kundu M, Yan Z. Ampk phosphorylation of Ulk1 is required for targeting of mitochondria to lysosomes in exercise-induced mitophagy. Nat Commun 2017; 8:548. [PMID: 28916822 PMCID: PMC5601463 DOI: 10.1038/s41467-017-00520-9] [Citation(s) in RCA: 313] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 07/05/2017] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial health is critical for skeletal muscle function and is improved by exercise training through both mitochondrial biogenesis and removal of damaged/dysfunctional mitochondria via mitophagy. The mechanisms underlying exercise-induced mitophagy have not been fully elucidated. Here, we show that acute treadmill running in mice causes mitochondrial oxidative stress at 3-12 h and mitophagy at 6 h post-exercise in skeletal muscle. These changes were monitored using a novel fluorescent reporter gene, pMitoTimer, that allows assessment of mitochondrial oxidative stress and mitophagy in vivo, and were preceded by increased phosphorylation of AMP activated protein kinase (Ampk) at tyrosine 172 and of unc-51 like autophagy activating kinase 1 (Ulk1) at serine 555. Using mice expressing dominant negative and constitutively active Ampk in skeletal muscle, we demonstrate that Ulk1 activation is dependent on Ampk. Furthermore, exercise-induced metabolic adaptation requires Ulk1. These findings provide direct evidence of exercise-induced mitophagy and demonstrate the importance of Ampk-Ulk1 signaling in skeletal muscle.Exercise is associated with biogenesis and removal of dysfunctional mitochondria. Here the authors use a mitochondrial reporter gene to demonstrate the occurrence of mitophagy following exercise in mice, and show this is dependent on AMPK and ULK1 signaling.
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Affiliation(s)
- Rhianna C Laker
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Joshua C Drake
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Rebecca J Wilson
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Vitor A Lira
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Department of Health and Human Physiology, Obesity Research and Education Initiative, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa, IA, 52242, USA
| | - Bevan M Lewellen
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Karen A Ryall
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Carleigh C Fisher
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Mei Zhang
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Jeffrey J Saucerman
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Laurie J Goodyear
- Research Division, Joslin Diabetes Center, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02215, USA
| | - Mondira Kundu
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Zhen Yan
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA. .,Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA. .,Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA. .,Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
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37
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Quattrocelli M, Salamone IM, Page PG, Warner JL, Demonbreun AR, McNally EM. Intermittent Glucocorticoid Dosing Improves Muscle Repair and Function in Mice with Limb-Girdle Muscular Dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2520-2535. [PMID: 28823869 DOI: 10.1016/j.ajpath.2017.07.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/03/2017] [Accepted: 07/13/2017] [Indexed: 12/17/2022]
Abstract
The muscular dystrophies are genetically diverse. Shared pathological features among muscular dystrophies include breakdown, or loss of muscle, and accompanying fibrotic replacement. Novel strategies are needed to enhance muscle repair and function and to slow this pathological remodeling. Glucocorticoid steroids, like prednisone, are known to delay loss of ambulation in patients with Duchenne muscular dystrophy but are accompanied by prominent adverse effects. However, less is known about the effects of steroid administration in other types of muscular dystrophies, including limb-girdle muscular dystrophies (LGMDs). LGMD 2B is caused by loss of dysferlin, a membrane repair protein, and LGMD 2C is caused by loss of the dystrophin-associated protein, γ-sarcoglycan. Herein, we assessed the efficacy of steroid dosing on sarcolemmal repair, muscle function, histopathology, and the regenerative capacity of primary muscle cells. We found that in murine models of LGMD 2B and 2C, daily prednisone dosing reduced muscle damage and fibroinflammatory infiltration. However, daily prednisone dosing also correlated with increased muscle adipogenesis and atrophic remodeling. Conversely, intermittent dosing of prednisone, provided once weekly, enhanced muscle repair and did not induce atrophy or adipogenesis, and was associated with improved muscle function. These data indicate that dosing frequency of glucocorticoid steroids affects muscle remodeling in non-Duchenne muscular dystrophies, suggesting a positive outcome associated with intermittent steroid dosing in LGMD 2B and 2C muscle.
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Affiliation(s)
- Mattia Quattrocelli
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Isabella M Salamone
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Patrick G Page
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - James L Warner
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Alexis R Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
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38
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Quattrocelli M, Barefield DY, Warner JL, Vo AH, Hadhazy M, Earley JU, Demonbreun AR, McNally EM. Intermittent glucocorticoid steroid dosing enhances muscle repair without eliciting muscle atrophy. J Clin Invest 2017; 127:2418-2432. [PMID: 28481224 DOI: 10.1172/jci91445] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/09/2017] [Indexed: 12/20/2022] Open
Abstract
Glucocorticoid steroids such as prednisone are prescribed for chronic muscle conditions such as Duchenne muscular dystrophy, where their use is associated with prolonged ambulation. The positive effects of chronic steroid treatment in muscular dystrophy are paradoxical because these steroids are also known to trigger muscle atrophy. Chronic steroid use usually involves once-daily dosing, although weekly dosing in children has been suggested for its reduced side effects on behavior. In this work, we tested steroid dosing in mice and found that a single pulse of glucocorticoid steroids improved sarcolemmal repair through increased expression of annexins A1 and A6, which mediate myofiber repair. This increased expression was dependent on glucocorticoid response elements upstream of annexins and was reinforced by the expression of forkhead box O1 (FOXO1). We compared weekly versus daily steroid treatment in mouse models of acute muscle injury and in muscular dystrophy and determined that both regimens provided comparable benefits in terms of annexin gene expression and muscle repair. However, daily dosing activated atrophic pathways, including F-box protein 32 (Fbxo32), which encodes atrogin-1. Conversely, weekly steroid treatment in mdx mice improved muscle function and histopathology and concomitantly induced the ergogenic transcription factor Krüppel-like factor 15 (Klf15) while decreasing Fbxo32. These findings suggest that intermittent, rather than daily, glucocorticoid steroid regimen promotes sarcolemmal repair and muscle recovery from injury while limiting atrophic remodeling.
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39
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García-Castañeda M, Vega AV, Rodríguez R, Montiel-Jaen MG, Cisneros B, Zarain-Herzberg A, Avila G. Functional impact of an oculopharyngeal muscular dystrophy mutation in PABPN1. J Physiol 2017; 595:4167-4187. [PMID: 28303574 DOI: 10.1113/jp273948] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/11/2017] [Indexed: 01/14/2023] Open
Abstract
KEY POINTS Mutations in the gene encoding poly(A)-binding protein nuclear 1 (PABPN1) result in oculopharyngeal muscular dystrophy (OPMD). This disease is of late-onset, but the underlying mechanism is unclear. Ca2+ stimulates muscle growth and contraction and, because OPMD courses with muscle atrophy and weakness, we hypothesized that the homeostasis of Ca2+ is altered in this disorder. C2C12 myotubes were transfected with cDNAs encoding either PABPN1 or the PABPN1-17A OPMD mutation. Subsequently, they were investigated concerning not only excitation-contraction coupling (ECC) and intracellular levels of Ca2+ , but also differentiation stage and nuclear structure. PABPN1-17A gave rise to: inhibition of Ca2+ release during ECC, depletion of sarcoplasmic reticulum Ca2+ content, reduced expression of ryanodine receptors, altered nuclear morphology and incapability to stimulate myoblast fusion. PABPN1-17A failed to inhibit ECC in adult muscle fibres, suggesting that its effects are primarily related to muscle regeneration. ABSTRACT Oculopharyngeal muscular dystrophy (OPMD) is linked to mutations in the gene encoding poly(A)-binding protein nuclear 1 (PABPN1). OPMD mutations consist of an expansion of a tract that contains 10 alanines (to 12-17). This disease courses with muscle weakness that begins in adulthood, but the underlying mechanism is unclear. In the present study, we investigated the functional effects of PABPN1 and an OPMD mutation (PABPN1-17A) using myotubes transfected with cDNAs encoding these proteins (GFP-tagged). PABPN1 stimulated myoblast fusion (100%), whereas PABPN1-17A failed to mimic this effect. Additionally, the OPMD mutation markedly altered nuclear morphology; specifically, it led to nuclei with a more convoluted and ovoid shape. Although PABPN1 and PABPN1-17A modified the expression of sarcoplasmic/endoplasmic reticulum Ca2+ -ATPase and calsequestrin, the corresponding changes did not have a clear impact on [Ca2+ ]. Interestingly, neither L-type Ca2+ channels, nor voltage-gated sarcoplasmic reticulum (SR) Ca2+ release (VGCR) was altered by PABPN1. However, PABPN1-17A produced a selective inhibition of VGCR (50%). This effect probably arises from both lower expression of RyR1 and depletion of SR Ca2+ . The latter, however, was not related to inhibition of store-operated Ca2+ entry. Both PABPN1 constructs promoted a moderated decrease in cytosolic [Ca2+ ], which apparently results from down-regulation of excitation-coupled Ca2+ entry. On the other hand, PABPN1-17A did not alter ECC in muscle fibres, suggesting that adult muscle is less prone to developing deleterious effects. These results demonstrate that PABPN1 proteins regulate essential processes during myotube formation and support the notion that OPMD involves disruption of myogenesis, nuclear structure and homeostasis of Ca2+ .
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Affiliation(s)
| | - Ana Victoria Vega
- UBIMED FES-Iztacala, National Autonomous University of Mexico, Mexico City, México
| | - Rocío Rodríguez
- Department of Molecular Biology, Cinvestav-IPN AP 14-740, México City, México
| | | | - Bulmaro Cisneros
- Department of Molecular Biology, Cinvestav-IPN AP 14-740, México City, México
| | - Angel Zarain-Herzberg
- Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, México
| | - Guillermo Avila
- Department of Biochemistry, Cinvestav-IPN AP 14-740, México City, México
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Osseni A, Sébastien M, Sarrault O, Baudet M, Couté Y, Fauré J, Fourest-Lieuvin A, Marty I. Triadin and CLIMP-63 form a link between triads and microtubules in muscle cells. J Cell Sci 2016; 129:3744-3755. [PMID: 27562070 DOI: 10.1242/jcs.188862] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 08/18/2016] [Indexed: 01/20/2023] Open
Abstract
In skeletal muscle, the triad is a structure comprising a transverse (T)-tubule and sarcoplasmic reticulum (SR) cisternae. Triads constitute the basis of excitation-contraction coupling as the cradle of the Ca2+ release complex. We have shown previously that triadin, a member of this complex, has shaping properties on reticulum membrane and is indirectly involved in a link between triads and microtubules. We have identified here that CLIMP-63 (also known as CKAP4), as the partner of triadin, is responsible for this association of triads and microtubules. Triadin and CLIMP-63 interact through their respective luminal domains and the shaping properties of triadin depend on the capacity of CLIMP-63 to bind microtubules with its cytosolic portion. In skeletal muscle, CLIMP-63 is localized in the SR, including triads, and is associated with the Ca2+ release complex through its interaction with triadin. Knockout of triadin in muscles results in the delocalization of CLIMP-63 from triads, its dissociation from the Ca2+ release complex and a disorganization of the microtubule network. Our results suggest that the association of triadin and CLIMP-63 could be involved in the shaping of SR terminal cisternae and in the guidance of microtubules close to the triads.
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Affiliation(s)
- Alexis Osseni
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble F-38000, France INSERM, U1216, Grenoble F-38000, France
| | - Muriel Sébastien
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble F-38000, France INSERM, U1216, Grenoble F-38000, France
| | - Oriana Sarrault
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble F-38000, France INSERM, U1216, Grenoble F-38000, France
| | - Mathieu Baudet
- University Grenoble Alpes, BIG-BGE, Grenoble F-38000, France CEA, BIG, BGE and GPC, Grenoble F-38000, France INSERM, BGE, Grenoble F-38000, France
| | - Yohann Couté
- University Grenoble Alpes, BIG-BGE, Grenoble F-38000, France CEA, BIG, BGE and GPC, Grenoble F-38000, France INSERM, BGE, Grenoble F-38000, France
| | - Julien Fauré
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble F-38000, France INSERM, U1216, Grenoble F-38000, France CHU de Grenoble, Grenoble F-38000, France
| | - Anne Fourest-Lieuvin
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble F-38000, France INSERM, U1216, Grenoble F-38000, France CEA, BIG, BGE and GPC, Grenoble F-38000, France
| | - Isabelle Marty
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble F-38000, France INSERM, U1216, Grenoble F-38000, France
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Demonbreun AR, Quattrocelli M, Barefield DY, Allen MV, Swanson KE, McNally EM. An actin-dependent annexin complex mediates plasma membrane repair in muscle. J Cell Biol 2016; 213:705-18. [PMID: 27298325 PMCID: PMC4915191 DOI: 10.1083/jcb.201512022] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 05/19/2016] [Indexed: 01/03/2023] Open
Abstract
Disruption of the plasma membrane often accompanies cellular injury, and in muscle, plasma membrane resealing is essential for efficient recovery from injury. Muscle contraction, especially of lengthened muscle, disrupts the sarcolemma. To define the molecular machinery that directs repair, we applied laser wounding to live mammalian myofibers and assessed translocation of fluorescently tagged proteins using high-resolution microscopy. Within seconds of membrane disruption, annexins A1, A2, A5, and A6 formed a tight repair "cap." Actin was recruited to the site of damage, and annexin A6 cap formation was both actin dependent and Ca(2+) regulated. Repair proteins, including dysferlin, EHD1, EHD2, MG53, and BIN1, localized adjacent to the repair cap in a "shoulder" region enriched with phosphatidlyserine. Dye influx into muscle fibers lacking both dysferlin and the related protein myoferlin was substantially greater than control or individual null muscle fibers, underscoring the importance of shoulder-localized proteins. These data define the cap and shoulder as subdomains within the repair complex accumulating distinct and nonoverlapping components.
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Affiliation(s)
| | | | - David Y Barefield
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611
| | - Madison V Allen
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611
| | - Kaitlin E Swanson
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611 Department of Pathology, The University of Chicago, Chicago, IL 60637
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Demonbreun AR, Allen MV, Warner JL, Barefield DY, Krishnan S, Swanson KE, Earley JU, McNally EM. Enhanced Muscular Dystrophy from Loss of Dysferlin Is Accompanied by Impaired Annexin A6 Translocation after Sarcolemmal Disruption. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:1610-22. [PMID: 27070822 DOI: 10.1016/j.ajpath.2016.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 01/20/2016] [Accepted: 02/11/2016] [Indexed: 02/03/2023]
Abstract
Dysferlin is a membrane-associated protein implicated in membrane resealing; loss of dysferlin leads to muscular dystrophy. We examined the same loss-of-function Dysf mutation in two different mouse strains, 129T2/SvEmsJ (Dysf(129)) and C57BL/6J (Dysf(B6)). Although there are many genetic differences between these two strains, we focused on polymorphisms in Anxa6 because these variants were previously associated with modifying a pathologically distinct form of muscular dystrophy and increased the production of a truncated annexin A6 protein. Dysferlin deficiency in the C57BL/6J background was associated with increased Evan's Blue dye uptake into muscle and increased serum creatine kinase compared to the 129T2/SvEmsJ background. In the C57BL/6J background, dysferlin loss was associated with enhanced pathologic severity, characterized by decreased mean fiber cross-sectional area, increased internalized nuclei, and increased fibrosis, compared to that in Dysf(129) mice. Macrophage infiltrate was also increased in Dysf(B6) muscle. High-resolution imaging of live myofibers demonstrated that fibers from Dysf(B6) mice displayed reduced translocation of full-length annexin A6 to the site of laser-induced sarcolemmal disruption compared to Dysf(129) myofibers, and impaired translocation of annexin A6 associated with impaired resealing of the sarcolemma. These results provide one mechanism by which the C57BL/6J background intensifies dysferlinopathy, giving rise to a more severe form of muscular dystrophy in the Dysf(B6) mouse model through increased membrane leak and inflammation.
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Affiliation(s)
| | - Madison V Allen
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois
| | - James L Warner
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois
| | - David Y Barefield
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois
| | - Swathi Krishnan
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Kaitlin E Swanson
- Department of Pathology, The University of Chicago, Chicago, Illinois
| | - Judy U Earley
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois
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Abstract
Mature muscle has a unique structure that is amenable to live cell imaging. Herein, we describe the experimental protocol for expressing fluorescently labeled proteins in the flexor digitorum brevis (FDB) muscle. Conditions have been optimized to provide a large number of high quality myofibers expressing the electroporated plasmid while minimizing muscle damage. The method employs fluorescent tags on various proteins. Combining this expression method with high resolution confocal microscopy permits live cell imaging, including imaging after laser-induced damage. Fluorescent dyes combined with imaging of fluorescently-tagged proteins provides information regarding the basic structure of muscle and its response to stimuli.
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Abstract
Since an intact membrane is required for normal cellular homeostasis, membrane repair is essential for cell survival. Human genetic studies, combined with the development of novel animal models and refinement of techniques to study cellular injury, have now uncovered series of repair proteins highly relevant for human health. Many of the deficient repair pathways manifest in skeletal muscle, where defective repair processes result in myopathies or other forms of muscle disease. Dysferlin is a membrane-associated protein implicated in sarcolemmal repair and also linked to other membrane functions including the maintenance of transverse tubules in muscle. MG53, annexins, and Eps15 homology domain-containing proteins interact with dysferlin to form a membrane repair complex and similarly have roles in membrane trafficking in muscle. These molecular features of membrane repair are not unique to skeletal muscle, but rather skeletal muscle, due to its high demands, is more dependent on an efficient repair process. Phosphatidylserine and phosphatidylinositol 4,5-bisphosphate, as well as Ca(2+), are central regulators of membrane organization during repair. Given the importance of muscle health in disease and in aging, these pathways are targets to enhance muscle function and recovery from injury.
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45
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Tang Y, Wang H, Wei B, Guo Y, Gu L, Yang Z, Zhang Q, Wu Y, Yuan Q, Zhao G, Ji G. CUG-BP1 regulates RyR1 ASI alternative splicing in skeletal muscle atrophy. Sci Rep 2015; 5:16083. [PMID: 26531141 PMCID: PMC4632035 DOI: 10.1038/srep16083] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/30/2015] [Indexed: 02/06/2023] Open
Abstract
RNA binding protein is identified as an important mediator of aberrant alternative splicing in muscle atrophy. The altered splicing of calcium channels, such as ryanodine receptors (RyRs), plays an important role in impaired excitation-contraction (E-C) coupling in muscle atrophy; however, the regulatory mechanisms of ryanodine receptor 1 (RyR1) alternative splicing leading to skeletal muscle atrophy remains to be investigated. In this study we demonstrated that CUG binding protein 1 (CUG-BP1) was up-regulated and the alternative splicing of RyR1 ASI (exon70) was aberrant during the process of neurogenic muscle atrophy both in human patients and mouse models. The gain and loss of function experiments in vivo demonstrated that altered splicing pattern of RyR1 ASI was directly mediated by an up-regulated CUG-BP1 function. Furthermore, we found that CUG-BP1 affected the calcium release activity in single myofibers and the extent of atrophy was significantly reduced upon gene silencing of CUG-BP1 in atrophic muscle. These findings improve our understanding of calcium signaling related biological function of CUG-BP1 in muscle atrophy. Thus, we provide an intriguing perspective of involvement of mis-regulated RyR1 splicing in muscular disease.
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Affiliation(s)
- Yinglong Tang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Huiwen Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Bin Wei
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Yuting Guo
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Lei Gu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiguang Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Qing Zhang
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Yanyun Wu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Qi Yuan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Gang Zhao
- Department of Neurology, Xijing Hospital, Forth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Guangju Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
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46
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Demonbreun AR, Swanson KE, Rossi AE, Deveaux HK, Earley JU, Allen MV, Arya P, Bhattacharyya S, Band H, Pytel P, McNally EM. Eps 15 Homology Domain (EHD)-1 Remodels Transverse Tubules in Skeletal Muscle. PLoS One 2015; 10:e0136679. [PMID: 26325203 PMCID: PMC4556691 DOI: 10.1371/journal.pone.0136679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/06/2015] [Indexed: 11/19/2022] Open
Abstract
We previously showed that Eps15 homology domain-containing 1 (EHD1) interacts with ferlin proteins to regulate endocytic recycling. Myoblasts from Ehd1-null mice were found to have defective recycling, myoblast fusion, and consequently smaller muscles. When expressed in C2C12 cells, an ATPase dead-EHD1 was found to interfere with BIN1/amphiphysin 2. We now extended those findings by examining Ehd1-heterozygous mice since these mice survive to maturity in normal Mendelian numbers and provide a ready source of mature muscle. We found that heterozygosity of EHD1 was sufficient to produce ectopic and excessive T-tubules, including large intracellular aggregates that contained BIN1. The disorganized T-tubule structures in Ehd1-heterozygous muscle were accompanied by marked elevation of the T-tubule-associated protein DHPR and reduction of the triad linker protein junctophilin 2, reflecting defective triads. Consistent with this, Ehd1-heterozygous muscle had reduced force production. Introduction of ATPase dead-EHD1 into mature muscle fibers was sufficient to induce ectopic T-tubule formation, seen as large BIN1 positive structures throughout the muscle. Ehd1-heterozygous mice were found to have strikingly elevated serum creatine kinase and smaller myofibers, but did not display findings of muscular dystrophy. These data indicate that EHD1 regulates the maintenance of T-tubules through its interaction with BIN1 and links T-tubules defects with elevated creatine kinase and myopathy.
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Affiliation(s)
- Alexis R. Demonbreun
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
- * E-mail:
| | - Kaitlin E. Swanson
- Department of Pathology, The University of Chicago, Chicago, IL, United States of America
| | - Ann E. Rossi
- Department of Medicine, The University of Chicago, Chicago, IL, United States of America
| | - H. Kieran Deveaux
- Department of Medicine, The University of Chicago, Chicago, IL, United States of America
| | - Judy U. Earley
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
| | - Madison V. Allen
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
| | - Priyanka Arya
- Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Sohinee Bhattacharyya
- Department of Pathology & Microbiology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Hamid Band
- Department of Pathology & Microbiology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Peter Pytel
- Department of Pathology, The University of Chicago, Chicago, IL, United States of America
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
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Lenhart KC, O'Neill TJ, Cheng Z, Dee R, Demonbreun AR, Li J, Xiao X, McNally EM, Mack CP, Taylor JM. GRAF1 deficiency blunts sarcolemmal injury repair and exacerbates cardiac and skeletal muscle pathology in dystrophin-deficient mice. Skelet Muscle 2015; 5:27. [PMID: 26301073 PMCID: PMC4546166 DOI: 10.1186/s13395-015-0054-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/04/2015] [Indexed: 11/18/2022] Open
Abstract
Background The plasma membranes of striated muscle cells are particularly susceptible to rupture as they endure significant mechanical stress and strain during muscle contraction, and studies have shown that defects in membrane repair can contribute to the progression of muscular dystrophy. The synaptotagmin-related protein, dysferlin, has been implicated in mediating rapid membrane repair through its ability to direct intracellular vesicles to sites of membrane injury. However, further work is required to identify the precise molecular mechanisms that govern dysferlin targeting and membrane repair. We previously showed that the bin–amphiphysin–Rvs (BAR)–pleckstrin homology (PH) domain containing Rho-GAP GTPase regulator associated with focal adhesion kinase-1 (GRAF1) was dynamically recruited to the tips of fusing myoblasts wherein it promoted membrane merging by facilitating ferlin-dependent capturing of intracellular vesicles. Because acute membrane repair responses involve similar vesicle trafficking complexes/events and because our prior studies in GRAF1-deficient tadpoles revealed a putative role for GRAF1 in maintaining muscle membrane integrity, we postulated that GRAF1 might also play an important role in facilitating dysferlin-dependent plasma membrane repair. Methods We used an in vitro laser-injury model to test whether GRAF1 was necessary for efficient muscle membrane repair. We also generated dystrophin/GRAF1 doubledeficient mice by breeding mdx mice with GRAF1 hypomorphic mice. Evans blue dye uptake and extensive morphometric analyses were used to assess sarcolemmal integrity and related pathologies in cardiac and skeletal muscles isolated from these mice. Results Herein, we show that GRAF1 is dynamically recruited to damaged skeletal and cardiac muscle plasma membranes and that GRAF1-depleted muscle cells have reduced membrane healing abilities. Moreover, we show that dystrophin depletion exacerbated muscle damage in GRAF1-deficient mice and that mice with dystrophin/GRAF1 double deficiency phenocopied the severe muscle pathologies observed in dystrophin/dysferlin-double null mice. Consistent with a model that GRAF1 facilitates dysferlin-dependent membrane patching, we found that GRAF1 associates with and regulates plasma membrane deposition of dysferlin. Conclusions Overall, our work indicates that GRAF1 facilitates dysferlin-dependent membrane repair following acute muscle injury. These findings indicate that GRAF1 might play a role in the phenotypic variation and pathological progression of cardiac and skeletal muscle degeneration in muscular dystrophy patients. Electronic supplementary material The online version of this article (doi:10.1186/s13395-015-0054-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kaitlin C Lenhart
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Thomas J O'Neill
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Zhaokang Cheng
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Rachel Dee
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Alexis R Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 USA
| | - Jianbin Li
- Department of Gene Therapy Molecular Pharmaceutics, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Xiao Xiao
- Department of Gene Therapy Molecular Pharmaceutics, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 USA
| | - Christopher P Mack
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
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Rokach O, Sekulic-Jablanovic M, Voermans N, Wilmshurst J, Pillay K, Heytens L, Zhou H, Muntoni F, Gautel M, Nevo Y, Mitrani-Rosenbaum S, Attali R, Finotti A, Gambari R, Mosca B, Jungbluth H, Zorzato F, Treves S. Epigenetic changes as a common trigger of muscle weakness in congenital myopathies. Hum Mol Genet 2015; 24:4636-47. [DOI: 10.1093/hmg/ddv195] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/22/2015] [Indexed: 12/13/2022] Open
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Cenik BK, Garg A, McAnally JR, Shelton JM, Richardson JA, Bassel-Duby R, Olson EN, Liu N. Severe myopathy in mice lacking the MEF2/SRF-dependent gene leiomodin-3. J Clin Invest 2015; 125:1569-78. [PMID: 25774500 DOI: 10.1172/jci80115] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 01/29/2015] [Indexed: 01/18/2023] Open
Abstract
Maintenance of skeletal muscle structure and function requires a precise stoichiometry of sarcomeric proteins for proper assembly of the contractile apparatus. Absence of components of the sarcomeric thin filaments causes nemaline myopathy, a lethal congenital muscle disorder associated with aberrant myofiber structure and contractility. Previously, we reported that deficiency of the kelch-like family member 40 (KLHL40) in mice results in nemaline myopathy and destabilization of leiomodin-3 (LMOD3). LMOD3 belongs to a family of tropomodulin-related proteins that promote actin nucleation. Here, we show that deficiency of LMOD3 in mice causes nemaline myopathy. In skeletal muscle, transcription of Lmod3 was controlled by the transcription factors SRF and MEF2. Myocardin-related transcription factors (MRTFs), which function as SRF coactivators, serve as sensors of actin polymerization and are sequestered in the cytoplasm by actin monomers. Conversely, conditions that favor actin polymerization de-repress MRTFs and activate SRF-dependent genes. We demonstrated that the actin nucleator LMOD3, together with its stabilizing partner KLHL40, enhances MRTF-SRF activity. In turn, SRF cooperated with MEF2 to sustain the expression of LMOD3 and other components of the contractile apparatus, thereby establishing a regulatory circuit to maintain skeletal muscle function. These findings provide insight into the molecular basis of the sarcomere assembly and muscle dysfunction associated with nemaline myopathy.
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50
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Mammucari C, Gherardi G, Zamparo I, Raffaello A, Boncompagni S, Chemello F, Cagnin S, Braga A, Zanin S, Pallafacchina G, Zentilin L, Sandri M, De Stefani D, Protasi F, Lanfranchi G, Rizzuto R. The mitochondrial calcium uniporter controls skeletal muscle trophism in vivo. Cell Rep 2015; 10:1269-79. [PMID: 25732818 DOI: 10.1016/j.celrep.2015.01.056] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/23/2014] [Accepted: 01/24/2015] [Indexed: 12/18/2022] Open
Abstract
Muscle atrophy contributes to the poor prognosis of many pathophysiological conditions, but pharmacological therapies are still limited. Muscle activity leads to major swings in mitochondrial [Ca(2+)], which control aerobic metabolism, cell death, and survival pathways. We investigated in vivo the effects of mitochondrial Ca(2+) homeostasis in skeletal muscle function and trophism by overexpressing or silencing the mitochondrial calcium uniporter (MCU). The results demonstrate that in both developing and adult muscles, MCU-dependent mitochondrial Ca(2+) uptake has a marked trophic effect that does not depend on aerobic control but impinges on two major hypertrophic pathways of skeletal muscle, PGC-1α4 and IGF1-Akt/PKB. In addition, MCU overexpression protects from denervation-induced atrophy. These data reveal a novel Ca(2+)-dependent organelle-to-nucleus signaling route that links mitochondrial function to the control of muscle mass and may represent a possible pharmacological target in conditions of muscle loss.
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Affiliation(s)
- Cristina Mammucari
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy.
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Ilaria Zamparo
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Anna Raffaello
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Simona Boncompagni
- Ce.S.I. (Center for Research on Ageing) and D.N.I.C.S. (Department of Neuroscience, Imaging and Clinical Sciences), University "G. D'Annunzio" of Chieti, Chieti 66100, Italy
| | - Francesco Chemello
- Department of Biology and CRIBI Biotechnology Center, University of Padua, Padua 35131, Italy
| | - Stefano Cagnin
- Department of Biology and CRIBI Biotechnology Center, University of Padua, Padua 35131, Italy
| | - Alessandra Braga
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Sofia Zanin
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Giorgia Pallafacchina
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy; Neuroscience Institute, National Research Council, Padua 35131, Italy
| | - Lorena Zentilin
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste 34159, Italy
| | - Marco Sandri
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy; Neuroscience Institute, National Research Council, Padua 35131, Italy; Dulbecco Telethon Institute at Venetian Institute of Molecular Medicine, Padua 35129, Italy; Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Feliciano Protasi
- Ce.S.I. (Center for Research on Ageing) and D.N.I.C.S. (Department of Neuroscience, Imaging and Clinical Sciences), University "G. D'Annunzio" of Chieti, Chieti 66100, Italy
| | - Gerolamo Lanfranchi
- Department of Biology and CRIBI Biotechnology Center, University of Padua, Padua 35131, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy; Neuroscience Institute, National Research Council, Padua 35131, Italy.
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