1
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Moutachi D, Hyzewicz J, Roy P, Lemaitre M, Bachasson D, Amthor H, Ritvos O, Li Z, Furling D, Agbulut O, Ferry A. Treadmill running and mechanical overloading improved the strength of the plantaris muscle in the dystrophin-desmin double knockout (DKO) mouse. J Physiol 2024; 602:3641-3660. [PMID: 38980963 DOI: 10.1113/jp286425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/24/2024] [Indexed: 07/11/2024] Open
Abstract
Limited knowledge exists regarding the chronic effect of muscular exercise on muscle function in a murine model of severe Duchenne muscular dystrophy (DMD). Here we determined the effects of 1 month of voluntary wheel running (WR), 1 month of enforced treadmill running (TR) and 1 month of mechanical overloading resulting from the removal of the synergic muscles (OVL) in mice lacking both dystrophin and desmin (DKO). Additionally, we examined the effect of activin receptor administration (AR). DKO mice, displaying severe muscle weakness, atrophy and greater susceptibility to contraction-induced functional loss, were exercised or treated with AR at 1 month of age and in situ force production of lower leg muscle was measured at the age of 2 months. We found that TR and OVL increased absolute maximal force and the rate of force development of the plantaris muscle in DKO mice. In contrast, those of the tibialis anterior (TA) muscle remained unaffected by TR and WR. Furthermore, the effects of TR and OVL on plantaris muscle function in DKO mice closely resembled those in mdx mice, a less severe murine DMD model. AR also improved absolute maximal force and the rate of force development of the TA muscle in DKO mice. In conclusion, exercise training improved plantaris muscle weakness in severely affected dystrophic mice. Consequently, these preclinical results may contribute to fostering further investigations aimed at assessing the potential benefits of exercise for DMD patients, particularly resistance training involving a low number of intense muscle contractions. KEY POINTS: Very little is known about the effects of exercise training in a murine model of severe Duchenne muscular dystrophy (DMD). One reason is that it is feared that chronic muscular exercise, particularly that involving intense muscle contractions, could exacerbate the disease. In DKO mice lacking both dystrophin and desmin, characterized by severe lower leg muscle weakness, atrophy and fragility in comparison to the less severe DMD mdx model, we found that enforced treadmill running improved absolute maximal force of the plantaris muscle, while that of tibialis anterior muscle remained unaffected by both enforced treadmill and voluntary wheel running. Furthermore, mechanical overloading, a non-physiological model of chronic resistance exercise, reversed plantaris muscle weakness. Consequently, our findings may have the potential to alleviate concerns and pave the way for exploring the prescription of endurance and resistance training as a viable therapeutic approach for the treatment of dystrophic patients. Additionally, such interventions may serve in mitigating the pathophysiological mechanisms induced by physical inactivity.
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Affiliation(s)
- Dylan Moutachi
- Sorbonne Université, INSERM U974, Centre de Recherche en Myologie, Paris, France
| | - Janek Hyzewicz
- Integrare Research Unit UMRS951, Université Paris-Saclay, Univ Evry, Inserm, Genethon, Evry, France
| | - Pauline Roy
- Sorbonne Université, INSERM U974, Centre de Recherche en Myologie, Paris, France
| | - Mégane Lemaitre
- Sorbonne Université, INSERM U974, Centre de Recherche en Myologie, Paris, France
| | - Damien Bachasson
- Institute of Myology, Neuromuscular Investigation Center, Neuromuscular Physiology and Evaluation Laboratory, Paris, France
| | - Helge Amthor
- Université de Versailles Saint-Quentin-en-Yvelines, INSERM U1179, Montigny-le-Bretonneux, France
| | - Olli Ritvos
- Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Zhenlin Li
- Sorbonne Université, Institut de Biologie Paris-Seine, UMR CNRS 8256, Inserm ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Denis Furling
- Sorbonne Université, INSERM U974, Centre de Recherche en Myologie, Paris, France
| | - Onnik Agbulut
- Sorbonne Université, Institut de Biologie Paris-Seine, UMR CNRS 8256, Inserm ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Arnaud Ferry
- Sorbonne Université, INSERM U974, Centre de Recherche en Myologie, Paris, France
- Université Paris Cité, Paris, France
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2
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Collins BC, Shapiro JB, Scheib MM, Musci RV, Verma M, Kardon G. Three-dimensional imaging studies in mice identify cellular dynamics of skeletal muscle regeneration. Dev Cell 2024; 59:1457-1474.e5. [PMID: 38569550 PMCID: PMC11153043 DOI: 10.1016/j.devcel.2024.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 12/06/2023] [Accepted: 03/08/2024] [Indexed: 04/05/2024]
Abstract
The function of many organs, including skeletal muscle, depends on their three-dimensional structure. Muscle regeneration therefore requires not only reestablishment of myofibers but also restoration of tissue architecture. Resident muscle stem cells (SCs) are essential for regeneration, but how SCs regenerate muscle architecture is largely unknown. We address this problem using genetic labeling of mouse SCs and whole-mount imaging to reconstruct, in three dimensions, muscle regeneration. Unexpectedly, we found that myofibers form via two distinct phases of fusion and the residual basement membrane of necrotic myofibers is critical for promoting fusion and orienting regenerated myofibers. Furthermore, the centralized myonuclei characteristic of regenerated myofibers are associated with myofibrillogenesis and endure months post injury. Finally, we elucidate two cellular mechanisms for the formation of branched myofibers, a pathology characteristic of diseased muscle. We provide a synthesis of the cellular events of regeneration and show that these differ from those used during development.
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Affiliation(s)
- Brittany C Collins
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Jacob B Shapiro
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Mya M Scheib
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Robert V Musci
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Mayank Verma
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gabrielle Kardon
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA.
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3
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Bibollet H, Nguyen EL, Miranda DR, Ward CW, Voss AA, Schneider MF, Hernández‐Ochoa EO. Voltage sensor current, SR Ca 2+ release, and Ca 2+ channel current during trains of action potential-like depolarizations of skeletal muscle fibers. Physiol Rep 2023; 11:e15675. [PMID: 37147904 PMCID: PMC10163276 DOI: 10.14814/phy2.15675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 05/07/2023] Open
Abstract
In skeletal muscle, CaV 1.1 serves as the voltage sensor for both excitation-contraction coupling (ECC) and L-type Ca2+ channel activation. We have recently adapted the technique of action potential (AP) voltage clamp (APVC) to monitor the current generated by the movement of intramembrane voltage sensors (IQ ) during single imposed transverse tubular AP-like depolarization waveforms (IQAP ). We now extend this procedure to monitoring IQAP , and Ca2+ currents during trains of tubular AP-like waveforms in adult murine skeletal muscle fibers, and compare them with the trajectories of APs and AP-induced Ca2+ release measured in other fibers using field stimulation and optical probes. The AP waveform remains relatively constant during brief trains (<1 sec) for propagating APs in non-V clamped fibers. Trains of 10 AP-like depolarizations at 10 Hz (900 ms), 50 Hz (180 ms), or 100 Hz (90 ms) did not alter IQAP amplitude or kinetics, consistent with previous findings in isolated muscle fibers where negligible charge immobilization occurred during 100 ms step depolarizations. Using field stimulation, Ca2+ release did exhibit a considerable decline from pulse to pulse during the train, also consistent with previous findings, indicating that the decline of Ca2+ release during a short train of APs is not correlated to modification of charge movement. Ca2+ currents during single or 10 Hz trains of AP-like depolarizations were hardly detectable, were minimal during 50 Hz trains, and became more evident during 100 Hz trains in some fibers. Our results verify predictions on the behavior of the ECC machinery in response to AP-like depolarizations and provide a direct demonstration that Ca2+ currents elicited by single AP-like waveforms are negligible, but can become more prominent in some fibers during short high-frequency train stimulation that elicits maximal isometric force.
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Affiliation(s)
- Hugo Bibollet
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Elton L. Nguyen
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Daniel R. Miranda
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Christopher W. Ward
- Department of OrthopedicsUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Andrew A. Voss
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Martin F. Schneider
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Erick O. Hernández‐Ochoa
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
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4
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Chan S, Kueh SLL, Morley JW, Head SI. Sarcoplasmic reticulum calcium handling in unbranched, immediately post-necrotic fast-twitch mdx fibres is similar to wild-type littermates. Exp Physiol 2022; 107:601-614. [PMID: 35471703 DOI: 10.1113/ep090057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 04/19/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS Central question: What are the early effects of dystrophin deficiency on SR Ca2+ handling in the mdx mouse? MAIN FINDING In the mdx mouse, Ca2+ handling by the SR is little affected by the absence of dystrophin when looking at fibres without branches that have just regenerated following massive myonecrosis. This has important implications for our understanding of Ca2+ pathology in the mdx mouse. ABSTRACT There is a variety of results in the literature regarding the effects of dystrophin deficiency on the Ca2+ -handling properties of the SR in mdx mice, an animal model of Duchenne muscular dystrophy. One possible source of variation is the presence of branched fibres. Fibre branching, a consequence of degenerative-regenerative processes such as muscular dystrophy, has in itself a significant influence on the function of the SR. In our present study we attempt to detect early effects of dystrophin deficiency on SR Ca2+ handling by using unbranched fibres from the immediate post-necrotic stage in mdx mice (just regenerated following massive necrosis). Using kinetically-corrected Fura-2 fluorescence signals measured during twitch and tetanus, we analysed the amplitude, rise time and decay time of Δ[Ca2+ ]i in unfatigued and fatigued fibres. Decay was also resolved into SR pump and SR leak components. Fibres from mdx mice were similar in all respects to fibres from wt littermates apart from: (i) a smaller amplitude of the initial spike of Δ[Ca2+ ]i during a tetanus; and (ii) a mitigation of the fall in Δ[Ca2+ ]i amplitude during the course of fatigue. Our findings suggest that the early effects of a loss of dystrophin on SR Ca2+ handling in mdx mice are subtle, and emphasise the importance of distinguishing between Ca2+ pathology that is due to lack of dystrophin and Ca2+ pathology that is due to muscle degeneration. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Stephen Chan
- School of Medicine, Western Sydney University, Campbelltown, New South Wales, Australia.,Department of Physiology, Faculty of Science, Mahidol University, Ratchatewi, Bangkok, Thailand
| | - Sindy L L Kueh
- School of Medicine, Western Sydney University, Campbelltown, New South Wales, Australia
| | - John W Morley
- School of Medicine, Western Sydney University, Campbelltown, New South Wales, Australia
| | - Stewart I Head
- School of Medicine, Western Sydney University, Campbelltown, New South Wales, Australia
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5
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Morris CE, Wheeler JJ, Joos B. The Donnan-dominated resting state of skeletal muscle fibers contributes to resilience and longevity in dystrophic fibers. J Gen Physiol 2022; 154:212743. [PMID: 34731883 PMCID: PMC8570295 DOI: 10.1085/jgp.202112914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 09/30/2021] [Indexed: 11/28/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked dystrophin-minus muscle-wasting disease. Ion homeostasis in skeletal muscle fibers underperforms as DMD progresses. But though DMD renders these excitable cells intolerant of exertion, sodium overloaded, depolarized, and spontaneously contractile, they can survive for several decades. We show computationally that underpinning this longevity is a strikingly frugal, robust Pump-Leak/Donnan (P-L/D) ion homeostatic process. Unlike neurons, which operate with a costly “Pump-Leak–dominated” ion homeostatic steady state, skeletal muscle fibers operate with a low-cost “Donnan-dominated” ion homeostatic steady state that combines a large chloride permeability with an exceptionally small sodium permeability. Simultaneously, this combination keeps fiber excitability low and minimizes pump expenditures. As mechanically active, long-lived multinucleate cells, skeletal muscle fibers have evolved to handle overexertion, sarcolemmal tears, ischemic bouts, etc.; the frugality of their Donnan dominated steady state lets them maintain the outsized pump reserves that make them resilient during these inevitable transient emergencies. Here, P-L/D model variants challenged with DMD-type insult/injury (low pump-strength, overstimulation, leaky Nav and cation channels) show how chronic “nonosmotic” sodium overload (observed in DMD patients) develops. Profoundly severe DMD ion homeostatic insult/injury causes spontaneous firing (and, consequently, unwanted excitation–contraction coupling) that elicits cytotoxic swelling. Therefore, boosting operational pump-strength and/or diminishing sodium and cation channel leaks should help extend DMD fiber longevity.
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Affiliation(s)
- Catherine E Morris
- Neuroscience, Ottawa Hospital Research Institute, Ottawa, Canada.,Center for Neural Dynamics, University of Ottawa, Ottawa, Canada
| | | | - Béla Joos
- Center for Neural Dynamics, University of Ottawa, Ottawa, Canada.,Department of Physics, University of Ottawa, Ottawa, Canada
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6
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Kiriaev L, Kueh S, Morley JW, North KN, Houweling PJ, Head SI. Lifespan Analysis of Dystrophic mdx Fast-Twitch Muscle Morphology and Its Impact on Contractile Function. Front Physiol 2021; 12:771499. [PMID: 34950049 PMCID: PMC8689589 DOI: 10.3389/fphys.2021.771499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Duchenne muscular dystrophy is caused by the absence of the protein dystrophin from skeletal muscle and is characterized by progressive cycles of necrosis/regeneration. Using the dystrophin deficient mdx mouse model, we studied the morphological and contractile chronology of dystrophic skeletal muscle pathology in fast-twitch Extensor Digitorum Longus muscles from animals 4–22 months of age containing 100% regenerated muscle fibers. Catastrophically, the older age groups lost ∼80% of their maximum force after one eccentric contraction (EC) of 20% strain with the greatest loss of ∼92% recorded in senescent 22-month-old mdx mice. In old age groups, there was minimal force recovery ∼24% after 120 min, correlated with a dramatic increase in the number and complexity of branched fibers. This data supports our two-phase model where a “tipping point” is reached when branched fibers rupture irrevocably on EC. These findings have important implications for pre-clinical drug studies and genetic rescue strategies.
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Affiliation(s)
- Leonit Kiriaev
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
- *Correspondence: Leonit Kiriaev,
| | - Sindy Kueh
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - John W. Morley
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Kathryn N. North
- Muscle Research Group, Murdoch Children’s Research Institute, Melbourne, VIC, Australia
| | - Peter J. Houweling
- Muscle Research Group, Murdoch Children’s Research Institute, Melbourne, VIC, Australia
| | - Stewart I. Head
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
- Muscle Research Group, Murdoch Children’s Research Institute, Melbourne, VIC, Australia
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7
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Geist Hauserman J, Stavusis J, Joca HC, Robinett JC, Hanft L, Vandermeulen J, Zhao R, Stains JP, Konstantopoulos K, McDonald KS, Ward C, Kontrogianni-Konstantopoulos A. Sarcomeric deficits underlie MYBPC1-associated myopathy with myogenic tremor. JCI Insight 2021; 6:e147612. [PMID: 34437302 PMCID: PMC8525646 DOI: 10.1172/jci.insight.147612] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 08/25/2021] [Indexed: 12/02/2022] Open
Abstract
Myosin binding protein-C slow (sMyBP-C) comprises a subfamily of cytoskeletal proteins encoded by MYBPC1 that is expressed in skeletal muscles where it contributes to myosin thick filament stabilization and actomyosin cross-bridge regulation. Recently, our group described the causal association of dominant missense pathogenic variants in MYBPC1 with an early-onset myopathy characterized by generalized muscle weakness, hypotonia, dysmorphia, skeletal deformities, and myogenic tremor, occurring in the absence of neuropathy. To mechanistically interrogate the etiologies of this MYBPC1-associated myopathy in vivo, we generated a knock-in mouse model carrying the E248K pathogenic variant. Using a battery of phenotypic, behavioral, and physiological measurements spanning neonatal to young adult life, we found that heterozygous E248K mice faithfully recapitulated the onset and progression of generalized myopathy, tremor occurrence, and skeletal deformities seen in human carriers. Moreover, using a combination of biochemical, ultrastructural, and contractile assessments at the level of the tissue, cell, and myofilaments, we show that the loss-of-function phenotype observed in mutant muscles is primarily driven by disordered and misaligned sarcomeres containing fragmented and out-of-register internal membranes that result in reduced force production and tremor initiation. Collectively, our findings provide mechanistic insights underscoring the E248K-disease pathogenesis and offer a relevant preclinical model for therapeutic discovery.
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Affiliation(s)
- Janelle Geist Hauserman
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Janis Stavusis
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Humberto C. Joca
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Joel C. Robinett
- Department of Medical Pharmacology and Physiology, University of Missouri, School of Medicine Columbia, Missouri, USA
| | - Laurin Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, School of Medicine Columbia, Missouri, USA
| | - Jack Vandermeulen
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Runchen Zhao
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Joseph P. Stains
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, School of Medicine Columbia, Missouri, USA
| | - Christopher Ward
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
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8
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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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9
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Kiriaev L, Kueh S, Morley JW, Houweling PJ, Chan S, North KN, Head SI. Dystrophin-negative slow-twitch soleus muscles are not susceptible to eccentric contraction induced injury over the lifespan of the mdx mouse. Am J Physiol Cell Physiol 2021; 321:C704-C720. [PMID: 34432537 DOI: 10.1152/ajpcell.00122.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 08/09/2021] [Indexed: 11/22/2022]
Abstract
Duchenne muscular dystrophy (DMD) is the second most common fatal genetic disease in humans and is characterized by the absence of a functional copy of the protein dystrophin from skeletal muscle. In dystrophin-negative humans and rodents, regenerated skeletal muscle fibers show abnormal branching. The number of fibers with branches and the complexity of branching increases with each cycle of degeneration/regeneration. Previously, using the mdx mouse model of DMD, we have proposed that once the number and complexity of branched fibers present in dystrophic fast-twitch EDL muscle surpasses a stable level, we term the "tipping point," the branches, in and of themselves, mechanically weaken the muscle by rupturing when subjected to high forces during eccentric contractions. Here, we use the slow-twitch soleus muscle from the dystrophic mdx mouse to study prediseased "periambulatory" dystrophy at 2-3 wk, the peak regenerative "adult" phase at 6-9 wk, and "old" at 58-112 wk. Using isolated mdx soleus muscles, we examined contractile function and response to eccentric contraction correlated with the amount and complexity of regenerated branched fibers. The intact muscle was enzymatically dispersed into individual fibers in order to count fiber branching and some muscles were optically cleared to allow laser scanning confocal microscopy. We demonstrate throughout the lifespan of the mdx mouse that dystrophic slow-twitch soleus muscle is no more susceptible to eccentric contraction-induced injury than age-matched littermate controls and that this is correlated with a reduction in the number and complexity of branched fibers compared with fast-twitch dystrophic EDL muscles.
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MESH Headings
- Age Factors
- Animals
- Disease Models, Animal
- Dystrophin/deficiency
- Dystrophin/genetics
- Kinetics
- Male
- Mice, Inbred mdx
- Muscle Contraction
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/pathology
- Muscle Strength
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Muscular Dystrophy, Duchenne/physiopathology
- Mutation
- Mice
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Affiliation(s)
- Leonit Kiriaev
- School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Sindy Kueh
- School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - John W Morley
- School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Peter J Houweling
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Stephen Chan
- School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Kathryn N North
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Stewart I Head
- School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
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10
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Chaffer TJ. The protective role of desmin in duchenne muscular dystrophy: Therapeutic insights. J Physiol 2020; 598:4759-4760. [PMID: 33231871 DOI: 10.1113/jp280325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Tomer Jordi Chaffer
- Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada.,Meakins-Christie Laboratories and Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Canada
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11
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Garcia-Pelagio KP, Pratt SJP, Lovering RM. Effects of myofiber isolation technique on sarcolemma biomechanics. Biotechniques 2020; 69:388-391. [PMID: 33000629 PMCID: PMC7686532 DOI: 10.2144/btn-2020-0087] [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] [Indexed: 11/23/2022] Open
Abstract
Isolated myofibers are commonly used to understand the function of skeletal muscle in vivo. This can involve single isolated myofibers obtained from dissection or from enzymatic dissociation. Isolation via dissection allows control of sarcomere length and preserves tendon attachment but is labor-intensive, time-consuming and yields few viable myofibers. In contrast, enzymatic dissociation is fast and facile, produces hundreds of myofibers, and more importantly reduces the number of muscles/animals needed for studies. Biomechanical properties of the sarcolemma have been studied using myofibers from the extensor digitorum longus, but this has been limited to dissected myofibers, making data collection slow and difficult. We have modified this tool to perform biomechanical measurements of the sarcolemma in dissociated myofibers from the flexor digitorum brevis.
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Affiliation(s)
- Karla P Garcia-Pelagio
- Departmento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Stephen JP Pratt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Richard M Lovering
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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12
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Implications of increased S100β and Tau5 proteins in dystrophic nerves of two mdx mouse models for Duchenne muscular dystrophy. Mol Cell Neurosci 2020; 105:103484. [DOI: 10.1016/j.mcn.2020.103484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/25/2020] [Indexed: 12/31/2022] Open
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13
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Chick embryonic cells as a source for generating in vitro model of muscle cell dystrophy. In Vitro Cell Dev Biol Anim 2018; 54:756-769. [DOI: 10.1007/s11626-018-0297-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/19/2018] [Indexed: 12/31/2022]
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Schneidereit D, Nübler S, Prölß G, Reischl B, Schürmann S, Müller OJ, Friedrich O. Optical prediction of single muscle fiber force production using a combined biomechatronics and second harmonic generation imaging approach. LIGHT, SCIENCE & APPLICATIONS 2018; 7:79. [PMID: 30374401 PMCID: PMC6199289 DOI: 10.1038/s41377-018-0080-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/19/2018] [Accepted: 09/24/2018] [Indexed: 05/22/2023]
Abstract
Skeletal muscle is an archetypal organ whose structure is tuned to match function. The magnitude of order in muscle fibers and myofibrils containing motor protein polymers determines the directed force output of the summed force vectors and, therefore, the muscle's power performance on the structural level. Structure and function can change dramatically during disease states involving chronic remodeling. Cellular remodeling of the cytoarchitecture has been pursued using noninvasive and label-free multiphoton second harmonic generation (SHG) microscopy. Hereby, structure parameters can be extracted as a measure of myofibrillar order and thus are suggestive of the force output that a remodeled structure can still achieve. However, to date, the parameters have only been an indirect measure, and a precise calibration of optical SHG assessment for an exerted force has been elusive as no technology in existence correlates these factors. We engineered a novel, automated, high-precision biomechatronics system into a multiphoton microscope allows simultaneous isometric Ca2+-graded force or passive viscoelasticity measurements and SHG recordings. Using this MechaMorph system, we studied force and SHG in single EDL muscle fibers from wt and mdx mice; the latter serves as a model for compromised force and abnormal myofibrillar structure. We present Ca2+-graded isometric force, pCa-force curves, passive viscoelastic parameters and 3D structure in the same fiber for the first time. Furthermore, we provide a direct calibration of isometric force to morphology, which allows noninvasive prediction of the force output of single fibers from only multiphoton images, suggesting a potential application in the diagnosis of myopathies.
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Affiliation(s)
- Dominik Schneidereit
- Institute of Medical Biotechnology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), FAU Erlangen-Nürnberg, Paul-Gordan-Str. 7, 91052 Erlangen, Germany
| | - Stefanie Nübler
- Institute of Medical Biotechnology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), FAU Erlangen-Nürnberg, Paul-Gordan-Str. 7, 91052 Erlangen, Germany
| | - Gerhard Prölß
- Institute of Medical Biotechnology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
| | - Barbara Reischl
- Institute of Medical Biotechnology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
| | - Sebastian Schürmann
- Institute of Medical Biotechnology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), FAU Erlangen-Nürnberg, Paul-Gordan-Str. 7, 91052 Erlangen, Germany
- Muscle Research Center Erlangen (MURCE), Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Oliver J Müller
- Department of Internal Medicine III, University of Kiel, Arnold-Heller-Str. 3, 24105 Kiel, Germany
- DZHK (German Center for Cardiovascular Research) Partner Site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), FAU Erlangen-Nürnberg, Paul-Gordan-Str. 7, 91052 Erlangen, Germany
- Muscle Research Center Erlangen (MURCE), Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
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15
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Robison P, Sussan TE, Chen H, Biswal S, Schneider MF, Hernández-Ochoa EO. Impaired calcium signaling in muscle fibers from intercostal and foot skeletal muscle in a cigarette smoke-induced mouse model of COPD. Muscle Nerve 2017; 56:282-291. [PMID: 27862020 PMCID: PMC5426995 DOI: 10.1002/mus.25466] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 11/02/2016] [Accepted: 11/09/2016] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Respiratory and locomotor skeletal muscle dysfunction are common findings in chronic obstructive pulmonary disease (COPD); however, the mechanisms that cause muscle impairment in COPD are unclear. Because Ca2+ signaling in excitation-contraction (E-C) coupling is important for muscle activity, we hypothesized that Ca2+ dysregulation could contribute to muscle dysfunction in COPD. METHODS Intercostal and flexor digitorum brevis muscles from control and cigarette smoke-exposed mice were investigated. We used single cell Ca2+ imaging and Western blot assays to assess Ca2+ signals and E-C coupling proteins. RESULTS We found impaired Ca2+ signals in muscle fibers from both muscle types, without significant changes in releasable Ca2+ or in the expression levels of E-C coupling proteins. CONCLUSIONS Ca2+ dysregulation may contribute or accompany respiratory and locomotor muscle dysfunction in COPD. These findings are of significance to the understanding of the pathophysiological course of COPD in respiratory and locomotor muscles. Muscle Nerve 56: 282-291, 2017.
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Affiliation(s)
- Patrick Robison
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Thomas E. Sussan
- Department of Environmental Health Sciences, Johns Hopkins University School of Public Health, Baltimore, Maryland 21205, USA
| | - Hegang Chen
- Division of Biostatistics and Bioinformatics, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Shyam Biswal
- Department of Environmental Health Sciences, Johns Hopkins University School of Public Health, Baltimore, Maryland 21205, USA
| | - Martin F. Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Erick O. Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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16
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Iyer SR, Shah SB, Valencia AP, Schneider MF, Hernández-Ochoa EO, Stains JP, Blemker SS, Lovering RM. Altered nuclear dynamics in MDX myofibers. J Appl Physiol (1985) 2016; 122:470-481. [PMID: 27979987 DOI: 10.1152/japplphysiol.00857.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 01/17/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic disorder in which the absence of dystrophin leads to progressive muscle degeneration and weakness. Although the genetic basis is known, the pathophysiology of dystrophic skeletal muscle remains unclear. We examined nuclear movement in wild-type (WT) and muscular dystrophy mouse model for DMD (MDX) (dystrophin-null) mouse myofibers. We also examined expression of proteins in the linkers of nucleoskeleton and cytoskeleton (LINC) complex, as well as nuclear transcriptional activity via histone H3 acetylation and polyadenylate-binding nuclear protein-1. Because movement of nuclei is not only LINC dependent but also microtubule dependent, we analyzed microtubule density and organization in WT and MDX myofibers, including the application of a unique 3D tool to assess microtubule core structure. Nuclei in MDX myofibers were more mobile than in WT myofibers for both distance traveled and velocity. MDX muscle shows reduced expression and labeling intensity of nesprin-1, a LINC protein that attaches the nucleus to the microtubule and actin cytoskeleton. MDX nuclei also showed altered transcriptional activity. Previous studies established that microtubule structure at the cortex is disrupted in MDX myofibers; our analyses extend these findings by showing that microtubule structure in the core is also disrupted. In addition, we studied malformed MDX myofibers to better understand the role of altered myofiber morphology vs. microtubule architecture in the underlying susceptibility to injury seen in dystrophic muscles. We incorporated morphological and microtubule architectural concepts into a simplified finite element mathematical model of myofiber mechanics, which suggests a greater contribution of myofiber morphology than microtubule structure to muscle biomechanical performance.NEW & NOTEWORTHY Microtubules provide the means for nuclear movement but show altered organization in the muscular dystrophy mouse model (MDX) (dystrophin-null) muscle. Here, MDX myofibers show increased nuclear movement, altered transcriptional activity, and altered linkers of nucleoskeleton and cytoskeleton complex expression compared with healthy myofibers. Microtubule architecture was incorporated in finite element modeling of passive stretch, revealing a role of fiber malformation, commonly found in MDX muscle. The results suggest that alterations in microtubule architecture in MDX muscle affect nuclear movement, which is essential for muscle function.
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Affiliation(s)
- Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Sameer B Shah
- Departments of Orthopaedic Surgery and Bioengineering, University of California San Diego, La Jolla, California
| | - Ana P Valencia
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Silvia S Blemker
- Department of Biomedical Engineering and Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia; and
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; .,Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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17
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Widrick JJ, Alexander MS, Sanchez B, Gibbs DE, Kawahara G, Beggs AH, Kunkel LM. Muscle dysfunction in a zebrafish model of Duchenne muscular dystrophy. Physiol Genomics 2016; 48:850-860. [PMID: 27764767 DOI: 10.1152/physiolgenomics.00088.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/29/2016] [Indexed: 01/10/2023] Open
Abstract
Sapje zebrafish lack the protein dystrophin and are the smallest vertebrate model of Duchenne muscular dystrophy (DMD). Their small size makes them ideal for large-scale drug discovery screens. However, the extent that sapje mimic the muscle dysfunction of higher vertebrate models of DMD is unclear. We used an optical birefringence assay to differentiate affected dystrophic sapje larvae from their unaffected siblings and then studied trunk muscle contractility at 4-7 days postfertilization. Preparation cross-sectional area (CSA) was similar for affected and unaffected larvae, yet tetanic forces of affected preparations were only 30-60% of normal. ANCOVA indicated that the linear relationship observed between tetanic force and CSA for unaffected preparations was absent in the affected population. Consequently, the average force/CSA of affected larvae was depressed 30-70%. Disproportionate reductions in twitch vs. tetanic force, and a slowing of twitch tension development and relaxation, indicated that the myofibrillar disorganization evident in the birefringence assay could not explain the entire force loss. Single eccentric contractions, in which activated preparations were lengthened 5-10%, resulted in tetanic force deficits in both groups of larvae. However, deficits of affected preparations were three- to fivefold greater at all strains and ages, even after accounting for any recovery. Based on these functional assessments, we conclude that the sapje mutant zebrafish is a phenotypically severe model of DMD. The severe contractile deficits of sapje larvae represent novel physiological endpoints for therapeutic drug screening.
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Affiliation(s)
- Jeffrey J Widrick
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts; .,Department of Pediatrics and Genetics, Harvard Medical School, Boston, Massachusetts
| | - Matthew S Alexander
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics and Genetics, Harvard Medical School, Boston, Massachusetts
| | - Benjamin Sanchez
- Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Devin E Gibbs
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts
| | - Genri Kawahara
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics and Genetics, Harvard Medical School, Boston, Massachusetts
| | - Alan H Beggs
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts.,The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts; and
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics and Genetics, Harvard Medical School, Boston, Massachusetts.,The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts; and.,Harvard Stem Cell Institute, Cambridge, Massachusetts
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18
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Roy P, Rau F, Ochala J, Messéant J, Fraysse B, Lainé J, Agbulut O, Butler-Browne G, Furling D, Ferry A. Dystrophin restoration therapy improves both the reduced excitability and the force drop induced by lengthening contractions in dystrophic mdx skeletal muscle. Skelet Muscle 2016; 6:23. [PMID: 27441081 PMCID: PMC4952281 DOI: 10.1186/s13395-016-0096-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/11/2016] [Indexed: 12/16/2022] Open
Abstract
Background The greater susceptibility to contraction-induced skeletal muscle injury (fragility) is an important dystrophic feature and tool for testing preclinic dystrophin-based therapies for Duchenne muscular dystrophy. However, how these therapies reduce the muscle fragility is not clear. Methods To address this question, we first determined the event(s) of the excitation-contraction cycle which is/are altered following lengthening (eccentric) contractions in the mdx muscle. Results We found that the immediate force drop following lengthening contractions, a widely used measure of muscle fragility, was associated with reduced muscle excitability. Moreover, the force drop can be mimicked by an experimental reduction in muscle excitation of uninjured muscle. Furthermore, the force drop was not related to major neuromuscular transmission failure, excitation-contraction uncoupling, and myofibrillar impairment. Secondly, and importantly, the re-expression of functional truncated dystrophin in the muscle of mdx mice using an exon skipping strategy partially prevented the reductions in both force drop and muscle excitability following lengthening contractions. Conclusion We demonstrated for the first time that (i) the increased susceptibility to contraction-induced muscle injury in mdx mice is mainly attributable to reduced muscle excitability; (ii) dystrophin-based therapy improves fragility of the dystrophic skeletal muscle by preventing reduction in muscle excitability.
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Affiliation(s)
- Pauline Roy
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Fredérique Rau
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Julien Ochala
- Centre of Human and Aerospace Physiological Sciences, King's College London, Guy's Campus, SE3 8TL London, UK
| | - Julien Messéant
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Bodvael Fraysse
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Jeanne Lainé
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Onnik Agbulut
- Biological Adaptation and Ageing, UMR CNRS 8256, Institut de Biologie Paris-Seine (IBPS), UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75005 France
| | - Gillian Butler-Browne
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Denis Furling
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France
| | - Arnaud Ferry
- Groupe Hospitalier Pitié Salpêtrière, Centre de Recherche en Myologie, CNRS, Inserm, UPMC Univ Paris 06, Sorbonne Universités, Paris, F-75013 France ; Sorbonne Paris Cité, Université Paris Descartes, Paris, F-75006 France ; Groupe Hospitalier Pitié-Salpétrière, Institut de Myologie, F-75013 Paris, France
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19
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Pichavant C, Burkholder TJ, Pavlath GK. Decrease of myofiber branching via muscle-specific expression of the olfactory receptor mOR23 in dystrophic muscle leads to protection against mechanical stress. Skelet Muscle 2016; 6:2. [PMID: 26798450 PMCID: PMC4721043 DOI: 10.1186/s13395-016-0077-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/05/2016] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Abnormal branched myofibers within skeletal muscles are commonly found in diverse animal models of muscular dystrophy as well as in patients. Branched myofibers from dystrophic mice are more susceptible to break than unbranched myofibers suggesting that muscles containing a high percentage of these myofibers are more prone to injury. Previous studies showed ubiquitous over-expression of mouse olfactory receptor 23 (mOR23), a G protein-coupled receptor, in wild type mice decreased myofiber branching. Whether mOR23 over-expression specifically in skeletal muscle cells is sufficient to mitigate myofiber branching in dystrophic muscle is unknown. METHODS We created a novel transgenic mouse over-expressing mOR23 specifically in muscle cells and then bred with dystrophic (mdx) mice. Myofiber branching was analyzed in these two transgenic mice and membrane integrity was assessed by Evans blue dye fluorescence. RESULTS mOR23 over-expression in muscle led to a decrease of myofiber branching after muscle regeneration in non-dystrophic mouse muscles and reduced the severity of myofiber branching in mdx mouse muscles. Muscles from mdx mouse over-expressing mOR23 significantly exhibited less damage to eccentric contractions than control mdx muscles. CONCLUSIONS The decrease of myofiber branching in mdx mouse muscles over-expressing mOR23 reduced the amount of membrane damage induced by mechanical stress. These results suggest that modifying myofiber branching in dystrophic patients, while not preventing degeneration, could be beneficial for mitigating some of the effects of the disease process.
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Affiliation(s)
- Christophe Pichavant
- Department of Pharmacology, Emory University, Atlanta, GA USA ; Present address: Department of Genetics, Stanford University, Stanford, CA USA
| | - Thomas J Burkholder
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA USA
| | - Grace K Pavlath
- Department of Pharmacology, Emory University, Atlanta, GA USA ; 1510 Clifton Road, Room 5024, Atlanta, GA 30322 USA
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20
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Hernández-Ochoa EO, Pratt SJP, Lovering RM, Schneider MF. Critical Role of Intracellular RyR1 Calcium Release Channels in Skeletal Muscle Function and Disease. Front Physiol 2016; 6:420. [PMID: 26793121 PMCID: PMC4709859 DOI: 10.3389/fphys.2015.00420] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/21/2015] [Indexed: 01/25/2023] Open
Abstract
The skeletal muscle Ca2+ release channel, also known as ryanodine receptor type 1 (RyR1), is the largest ion channel protein known and is crucial for effective skeletal muscle contractile activation. RyR1 function is controlled by Cav1.1, a voltage gated Ca2+ channel that works mainly as a voltage sensor for RyR1 activity during skeletal muscle contraction and is also fine-tuned by Ca2+, several intracellular compounds (e.g., ATP), and modulatory proteins (e.g., calmodulin). Dominant and recessive mutations in RyR1, as well as acquired channel alterations, are the underlying cause of various skeletal muscle diseases. The aim of this mini review is to summarize several current aspects of RyR1 function, structure, regulation, and to describe the most common diseases caused by hereditary or acquired RyR1 malfunction.
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Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
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21
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Xu S, Shi D, Pratt SJP, Zhu W, Marshall A, Lovering RM. Abnormalities in brain structure and biochemistry associated with mdx mice measured by in vivo MRI and high resolution localized (1)H MRS. Neuromuscul Disord 2015; 25:764-72. [PMID: 26236031 DOI: 10.1016/j.nmd.2015.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 06/21/2015] [Accepted: 07/06/2015] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD), an X-linked disorder caused by the lack of dystrophin, is characterized by the progressive wasting of skeletal muscles. To date, what is known about dystrophin function is derived from studies of dystrophin-deficient animals, with the most common model being the mdx mouse. Most studies on patients with DMD and in mdx mice have focused on skeletal muscle and the development of therapies to reverse, or at least slow, the severe muscle wasting and progressive degeneration. However, dystrophin is also expressed in the CNS. Both mdx mice and patients with DMD can have cognitive and behavioral changes, but studies in the dystrophic brain are limited. We examined the brain structure and metabolites of mature wild type (WT) and mdx mice using magnetic resonance imaging and spectroscopy (MRI/MRS). Both structural and metabolic alterations were observed in the mdx brain. Enlarged lateral ventricles were detected in mdx mice when compared to WT. Diffusion tensor imaging (DTI) revealed elevations in diffusion diffusivities in the prefrontal cortex and a reduction of fractional anisotropy in the hippocampus. Metabolic changes included elevations in phosphocholine and glutathione, and a reduction in γ-aminobutyric acid in the hippocampus. In addition, an elevation in taurine was observed in the prefrontal cortex. Such findings indicate a regional structural change, altered cellular antioxidant defenses, a dysfunction of GABAergic neurotransmission, and a perturbed osmoregulation in the brain lacking dystrophin.
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Affiliation(s)
- Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Da Shi
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Stephen J P Pratt
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Andrew Marshall
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, MD, USA.
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