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Gaglianone RB, Launikonis BS. Muscle fibre mitochondrial [Ca 2+ ] dynamics during Ca 2+ waves in RYR1 gain-of-function mouse. Acta Physiol (Oxf) 2024; 240:e14098. [PMID: 38240476 DOI: 10.1111/apha.14098] [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: 08/28/2023] [Revised: 11/14/2023] [Accepted: 01/01/2024] [Indexed: 02/24/2024]
Abstract
AIM A fraction of the Ca2+ released from the sarcoplasmic reticulum (SR) enters mitochondria to transiently increase its [Ca2+ ] ([Ca2+ ]mito ). This transient [Ca2+ ]mito increase may be important in the resynthesis of ATP and other processes. The resynthesis of ATP in the mitochondria generates heat that can lead to hypermetabolic reactions in muscle with ryanodine receptor 1 (RyR1) variants during the cyclic releasing of SR Ca2+ in the presence of a RyR1 agonist. We aimed to analyse whether the mitochondria of RYR1 variant muscle handles Ca2+ differently from healthy muscle. METHODS We used confocal microscopy to track mitochondrial and cytoplasmic Ca2+ with fluorescent dyes simultaneously during caffeine-induced Ca2+ waves in extensor digitorum longus muscle fibres from healthy mice and mice heterozygous (HET) for a malignant hyperthermia-causative RYR1 variant. RESULTS Mitochondrial Ca2+ -transient peaks trailed the peak of cytoplasmic Ca2+ transients by many seconds with [Ca2+ ]mito not increasing by more than 250 nM. A strong linear relationship between cytoplasmic Ca2+ and [Ca2+ ]mito amplitudes was observed in HET RYR1 KI fibres but not wild type (WT). CONCLUSION Our results indicate that [Ca2+ ]mito change within the nM range during SR Ca2+ release. HET fibre mitochondria are more sensitive to SR Ca2+ release flux than WT. This may indicate post-translation modification differences of the mitochondrial Ca2+ uniporter between the genotypes.
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Affiliation(s)
- Rhayanna B Gaglianone
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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2
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Marcucci L, Michelucci A, Reggiani C. Cytosolic Ca 2+ gradients and mitochondrial Ca 2+ uptake in resting muscle fibers: A model analysis. BIOPHYSICAL REPORTS 2023; 3:100117. [PMID: 37576797 PMCID: PMC10412765 DOI: 10.1016/j.bpr.2023.100117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/12/2023] [Indexed: 08/15/2023]
Abstract
Calcium ions (Ca2+) enter mitochondria via the mitochondrial Ca2+ uniporter, driven by electrical and concentration gradients. In this regard, transgenic mouse models, such as calsequestrin knockout (CSQ-KO) mice, with higher mitochondrial Ca2+ concentrations ([Ca2+]mito), should display higher cytosolic Ca2+ concentrations ([Ca2+]cyto). However, repeated measurements of [Ca2+]cyto in quiescent CSQ-KO fibers never showed a difference between WT and CSQ-KO. Starting from the consideration that fluorescent Ca2+ probes (Fura-2 and Indo-1) measure averaged global cytosolic concentrations, in this report we explored the role of local Ca2+ concentrations (i.e., Ca2+ microdomains) in regulating mitochondrial Ca2+ in resting cells, using a multicompartmental diffusional Ca2+ model. Progressively including the inward and outward fluxes of sarcoplasmic reticulum (SR), extracellular space, and mitochondria, we explored their contribution to the local Ca2+ distribution within the cell. The model predicts Ca2+ concentration gradients with hot spots or microdomains even at rest, minor but similar to those of evoked Ca2+ release. Due to their specific localization close to Ca2+ release units (CRU), mitochondria could take up Ca2+ directly from high-concentration microdomains, thus sensibly raising [Ca2+]mito, despite minor, possibly undetectable, modifications of the average [Ca2+]cyto.
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Affiliation(s)
- Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Center for Biosystems Dynamics Research, RIKEN, Suita, Japan
| | - Antonio Michelucci
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia
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3
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Barclay CJ, Curtin NA. Advances in understanding the energetics of muscle contraction. J Biomech 2023; 156:111669. [PMID: 37302165 DOI: 10.1016/j.jbiomech.2023.111669] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 05/30/2023] [Indexed: 06/13/2023]
Abstract
Muscle energetics encompasses the relationships between mechanical performance and the biochemical and thermal changes that occur during muscular activity. The biochemical reactions that underpin contraction are described and the way in which these are manifest in experimental recordings, as initial and recovery heat, is illustrated. Energy use during contraction can be partitioned into that related to cross-bridge force generation and that associated with activation by Ca2+. Activation processes account for 25-45% of ATP turnover in an isometric contraction, varying amongst muscles. Muscle energy use during contraction depends on the nature of the contraction. When shortening muscles produce less force than when contracting isometrically but use energy at a greater rate. These characteristics reflect more rapid cross-bridge cycling when shortening. When lengthening, muscles produce more force than in an isometric contraction but use energy at a lower rate. In that case, cross-bridges cycle but via a pathway in which ATP splitting is not completed. Shortening muscles convert part of the free energy available from ATP hydrolysis into work with the remainder appearing as heat. In the most efficient muscle studied, that of a tortoise, cross-bridges convert a maximum of 47% of the available energy into work. In most other muscles, only 20-30% of the free energy from ATP hydrolysis is converted into work.
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Affiliation(s)
- C J Barclay
- School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, Australia.
| | - N A Curtin
- Cardio-Respiratory Interface, NHLI, Imperial College London, London SW7 2AZ, UK
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4
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Fernández-Peña C, Reimúndez A, Viana F, Arce VM, Señarís R. Sex differences in thermoregulation in mammals: Implications for energy homeostasis. Front Endocrinol (Lausanne) 2023; 14:1093376. [PMID: 36967809 PMCID: PMC10030879 DOI: 10.3389/fendo.2023.1093376] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/06/2023] [Indexed: 03/10/2023] Open
Abstract
Thermal homeostasis is a fundamental process in mammals, which allows the maintenance of a constant internal body temperature to ensure an efficient function of cells despite changes in ambient temperature. Increasing evidence has revealed the great impact of thermoregulation on energy homeostasis. Homeothermy requires a fine regulation of food intake, heat production, conservation and dissipation and energy expenditure. A great interest on this field of research has re-emerged following the discovery of thermogenic brown adipose tissue and browning of white fat in adult humans, with a potential clinical relevance on obesity and metabolic comorbidities. However, most of our knowledge comes from male animal models or men, which introduces unwanted biases on the findings. In this review, we discuss how differences in sex-dependent characteristics (anthropometry, body composition, hormonal regulation, and other sexual factors) influence numerous aspects of thermal regulation, which impact on energy homeostasis. Individuals of both sexes should be used in the experimental paradigms, considering the ovarian cycles and sexual hormonal regulation as influential factors in these studies. Only by collecting data in both sexes on molecular, functional, and clinical aspects, we will be able to establish in a rigorous way the real impact of thermoregulation on energy homeostasis, opening new avenues in the understanding and treatment of obesity and metabolic associated diseases.
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Affiliation(s)
| | - Alfonso Reimúndez
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Félix Viana
- Institute of Neuroscience, University Miguel Hernández (UMH)-CSIC, Alicante, Spain
| | - Victor M. Arce
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- *Correspondence: Rosa Señarís, ; Victor M. Arce,
| | - Rosa Señarís
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- *Correspondence: Rosa Señarís, ; Victor M. Arce,
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5
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Bolaños P, Calderón JC. Excitation-contraction coupling in mammalian skeletal muscle: Blending old and last-decade research. Front Physiol 2022; 13:989796. [PMID: 36117698 PMCID: PMC9478590 DOI: 10.3389/fphys.2022.989796] [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: 07/08/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
The excitation–contraction coupling (ECC) in skeletal muscle refers to the Ca2+-mediated link between the membrane excitation and the mechanical contraction. The initiation and propagation of an action potential through the membranous system of the sarcolemma and the tubular network lead to the activation of the Ca2+-release units (CRU): tightly coupled dihydropyridine and ryanodine (RyR) receptors. The RyR gating allows a rapid, massive, and highly regulated release of Ca2+ from the sarcoplasmic reticulum (SR). The release from triadic places generates a sarcomeric gradient of Ca2+ concentrations ([Ca2+]) depending on the distance of a subcellular region from the CRU. Upon release, the diffusing Ca2+ has multiple fates: binds to troponin C thus activating the contractile machinery, binds to classical sarcoplasmic Ca2+ buffers such as parvalbumin, adenosine triphosphate and, experimentally, fluorescent dyes, enters the mitochondria and the SR, or is recycled through the Na+/Ca2+ exchanger and store-operated Ca2+ entry (SOCE) mechanisms. To commemorate the 7th decade after being coined, we comprehensively and critically reviewed “old”, historical landmarks and well-established concepts, and blended them with recent advances to have a complete, quantitative-focused landscape of the ECC. We discuss the: 1) elucidation of the CRU structures at near-atomic resolution and its implications for functional coupling; 2) reliable quantification of peak sarcoplasmic [Ca2+] using fast, low affinity Ca2+ dyes and the relative contributions of the Ca2+-binding mechanisms to the whole concert of Ca2+ fluxes inside the fibre; 3) articulation of this novel quantitative information with the unveiled structural details of the molecular machinery involved in mitochondrial Ca2+ handing to understand how and how much Ca2+ enters the mitochondria; 4) presence of the SOCE machinery and its different modes of activation, which awaits understanding of its magnitude and relevance in situ; 5) pharmacology of the ECC, and 6) emerging topics such as the use and potential applications of super-resolution and induced pluripotent stem cells (iPSC) in ECC. Blending the old with the new works better!
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Affiliation(s)
- Pura Bolaños
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Juan C. Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín, Colombia
- *Correspondence: Juan C. Calderón,
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6
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Reggiani C, Marcucci L. A controversial issue: Can mitochondria modulate cytosolic calcium and contraction of skeletal muscle fibers? J Gen Physiol 2022; 154:213356. [PMID: 35849108 PMCID: PMC9297197 DOI: 10.1085/jgp.202213167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mitochondria are characterized by a high capacity to accumulate calcium thanks to the electrochemical gradient created by the extrusion of protons in the respiratory chain. Thereby calcium can enter crossing the inner mitochondrial membrane via MCU complex, a high-capacity, low-affinity transport mechanism. Calcium uptake serves numerous purposes, among them the regulation of three dehydrogenases of the citric cycle, apoptosis via permeability transition, and, in some cell types, modulation of cytosolic calcium transients. This Review is focused on mitochondrial calcium uptake in skeletal muscle fibers and aims to reanalyze its functional impact. In particular, we ask whether mitochondrial calcium uptake is relevant for the control of cytosolic calcium transients and therefore of contractile performance. Recent data suggest that this may be the case, at least in particular conditions, as modified expression of MCU complex subunits or of proteins involved in mitochondrial dynamics and ablation of the main cytosolic calcium buffer, parvalbumin.
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Affiliation(s)
- Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Padova, Italy,Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia,Correspondence to Carlo Reggiani:
| | - Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, Padova, Italy,Center for Biosystems Dynamics Research, RIKEN, Suita, Japan
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7
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Barclay CJ, Launikonis BS. A mathematical model to quantify RYR Ca2+ leak and associated heat production in resting human skeletal muscle fibers. J Gen Physiol 2022; 154:213077. [PMID: 35311921 PMCID: PMC9037342 DOI: 10.1085/jgp.202112994] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/06/2022] [Indexed: 02/02/2023] Open
Abstract
Cycling of Ca2+ between the sarcoplasmic reticulum (SR) and myoplasm is an important component of skeletal muscle resting metabolism. As part of this cycle, Ca2+ leaks from the SR into the myoplasm and is pumped back into the SR using ATP, which leads to the consumption of O2 and generation of heat. Ca2+ may leak through release channels or ryanodine receptors (RYRs). RYR Ca2+ leak can be monitored in a skinned fiber preparation in which leaked Ca2+ is pumped into the t-system and measured with a fluorescent dye. However, accurate quantification faces a number of hurdles. To overcome them, we developed a mathematical model of Ca2+ movement in these preparations. The model incorporated Ca2+ pumps that move Ca2+ from the myoplasm to the SR and from the junctional space (JS) to the t-system, Ca2+ buffering by EGTA in the JS and myoplasm and by buffers in the SR, and Ca2+ leaks from the SR into the JS and myoplasm and from the t-system into the myoplasm. The model accurately simulated Ca2+ uptake into the t-system, the relationship between myoplasmic [Ca2+] and steady-state t-system [Ca2+], and the effect of blocking RYR Ca2+ leak on t-system Ca2+ uptake. The magnitude of the leak through the RYRs would contribute ∼5% of the resting heat production of human muscle. In normal resting fibers, RYR Ca2+ leak makes a small contribution to resting metabolism. RYR-focused pathologies have the potential to increase RYR Ca2+ leak and the RYR leak component of resting metabolism.
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8
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Barclay CJ, Curtin NA. The legacy of A. V. Hill's Nobel Prize winning work on muscle energetics. J Physiol 2022; 600:1555-1578. [PMID: 35114037 PMCID: PMC9304278 DOI: 10.1113/jp281556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/24/2022] [Indexed: 11/08/2022] Open
Abstract
A. V. Hill was awarded the 1922 Nobel Prize, jointly with Otto Meyerhof, for Physiology or Medicine for his work on energetic aspects of muscle contraction. Hill used his considerable mathematical and experimental skills to investigate the relationships among muscle mechanics, biochemistry and heat production. The main ideas of the work for which the Nobel Prize was awarded were superseded within a decade and the legacy of Hill and Meyerhof's Nobel work was not a set of persistent, influential ideas but rather was a prolonged period of extraordinary activity that advanced the understanding of how muscles work far beyond the concepts that led to the Nobel Prize. Hill pioneered the integration of mathematics into the study of physiology and pharmacology. Particular aspects of Hill's own work that remain in common use in muscle physiology include mathematical descriptions of the relationships between muscle force output and shortening velocity and between force output and calcium concentration and the model of muscle as a contractile element in series with an elastic element. We describe some of the characteristics of Hill's broader scientific activities and then outline how Hill's work on muscle energetics was extended after 1922, as a result of Hill's own work and that of others, to the present day. Abstract figure legend. A. V. Hill's scientific legacy. Vertical from the base. A. V. Hill (pictured) and his colleague Otto Meyerhof shared the 1922 Nobel Prize for Physiology or Medicine. Seven enduring elements of Hill's legacy to muscle physiology are shown. Arrows link concepts and approaches to related disciplines where they have been foundational and highly influential. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- C J Barclay
- School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, Australia
| | - N A Curtin
- Cardio-Respiratory Interface, NHLI, Imperial College London, London, SW7 2AZ, UK
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9
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Ca 2+ leak through ryanodine receptor 1 regulates thermogenesis in resting skeletal muscle. Proc Natl Acad Sci U S A 2022; 119:2119203119. [PMID: 35046046 PMCID: PMC8794839 DOI: 10.1073/pnas.2119203119] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2021] [Indexed: 11/26/2022] Open
Abstract
The evolution of mammals to use skeletal muscle as a source of heat allowed them to spread to all parts of the globe. The generation of heat requires increased adenosine triphosphate (ATP) hydrolysis in the resting muscle in a regulated manner, but how this mechanism works is unknown. The results suggest that mammals increase their RyR1 Ca2+ leak rate to amplify a basal ATP turnover rate at the sarcoplasmic reticulum Ca2+ pump that is higher than that of lower vertebrates. Muscle-based thermogenesis allows regulation of body temperature that is essential for life in mammals and provides a potential pathway for manipulating body weight or temperature by altering metabolic rate. Mammals rely on nonshivering thermogenesis (NST) from skeletal muscle so that cold temperatures can be tolerated. NST results from activity of the sarcoplasmic reticulum (SR) Ca2+ pump in skeletal muscle, but the mechanisms that regulate this activity are unknown. Here, we develop a single-fiber assay to investigate the role of Ca2+ leak through ryanodine receptor 1 (RyR1) to generate heat at the SR Ca2+ pump in resting muscle. By inhibiting a subpopulation of RyR1s in a single-fiber preparation via targeted delivery of ryanodine through transverse tubules, we achieve in-preparation isolation of RyR1 Ca2+ leak. This maneuver provided a critical increase in signal-to-noise of the SR-temperature-sensitive dye ER thermoyellow fluorescence signal from the fiber to allow detection of SR temperature changes as either RyR1 or SR Ca2+ pump activity was altered. We found that RyR1 Ca2+ leak raises cytosolic [Ca2+] in the local vicinity of the SR Ca2+ pump to amplify thermogenesis. Furthermore, gene-dose-dependent increases in RyR1 leak in RYR1 mutant mice result in progressive rises in leak-dependent heat, consistent with raised local [Ca2+] at the SR Ca2+ pump via RyR1 Ca2+ leak. We also show that basal RyR Ca2+ leak and the heat generated by the SR Ca2+ pump in the absence of RyR Ca2+ leak is greater in fibers from mice than from toads. The distinct function of RyRs and SR Ca2+ pump in endothermic mammals compared to ectothermic amphibians provides insights into the mechanisms by which mammalian skeletal muscle achieves thermogenesis at rest.
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10
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Rincón OA, Milán AF, Calderón JC, Giraldo MA. Comprehensive Simulation of Ca 2+ Transients in the Continuum of Mouse Skeletal Muscle Fiber Types. Int J Mol Sci 2021; 22:12378. [PMID: 34830262 PMCID: PMC8624975 DOI: 10.3390/ijms222212378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/01/2021] [Accepted: 10/12/2021] [Indexed: 01/19/2023] Open
Abstract
Mag-Fluo-4 has revealed differences in the kinetics of the Ca2+ transients of mammalian fiber types (I, IIA, IIX, and IIB). We simulated the changes in [Ca2+] through the sarcomere of these four fiber types, considering classical (troponin -Tn-, parvalbumin -Pv-, adenosine triphosphate -ATP-, sarcoplasmic reticulum Ca2+ pump -SERCA-, and dye) and new (mitochondria -MITO-, Na+/Ca2+ exchanger -NCX-, and store-operated calcium entry -SOCE-) Ca2+ binding sites, during single and tetanic stimulation. We found that during a single twitch, the sarcoplasmic peak [Ca2+] for fibers type IIB and IIX was around 16 µM, and for fibers type I and IIA reached 10-13 µM. The release rate in fibers type I, IIA, IIX, and IIB was 64.8, 153.6, 238.8, and 244.5 µM ms-1, respectively. Both the pattern of change and the peak concentrations of the Ca2+-bound species in the sarcoplasm (Tn, PV, ATP, and dye), the sarcolemma (NCX, SOCE), and the SR (SERCA) showed the order IIB ≥ IIX > IIA > I. The capacity of the NCX was 2.5, 1.3, 0.9, and 0.8% of the capacity of SERCA, for fibers type I, IIA, IIX, and IIB, respectively. MITO peak [Ca2+] ranged from 0.93 to 0.23 µM, in fibers type I and IIB, respectively, while intermediate values were obtained in fibers IIA and IIX. The latter numbers doubled during tetanic stimulation. In conclusion, we presented a comprehensive mathematical model of the excitation-contraction coupling that integrated most classical and novel Ca2+ handling mechanisms, overcoming the limitations of the fast- vs. slow-fibers dichotomy and the use of slow dyes.
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Affiliation(s)
- Oscar A. Rincón
- Biophysics Group, Institute of Physics, University of Antioquia, Medellín 050010, Colombia;
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín 050010, Colombia; (A.F.M.); (J.C.C.)
| | - Andrés F. Milán
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín 050010, Colombia; (A.F.M.); (J.C.C.)
| | - Juan C. Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín 050010, Colombia; (A.F.M.); (J.C.C.)
| | - Marco A. Giraldo
- Biophysics Group, Institute of Physics, University of Antioquia, Medellín 050010, Colombia;
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11
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Lamboley CR, Pearce L, Seng C, Meizoso-Huesca A, Singh DP, Frankish BP, Kaura V, Lo HP, Ferguson C, Allen PD, Hopkins PM, Parton RG, Murphy RM, van der Poel C, Barclay CJ, Launikonis BS. Ryanodine receptor leak triggers fiber Ca 2+ redistribution to preserve force and elevate basal metabolism in skeletal muscle. SCIENCE ADVANCES 2021; 7:eabi7166. [PMID: 34705503 PMCID: PMC8550231 DOI: 10.1126/sciadv.abi7166] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Muscle contraction depends on tightly regulated Ca2+ release. Aberrant Ca2+ leak through ryanodine receptor 1 (RyR1) on the sarcoplasmic reticulum (SR) membrane can lead to heatstroke and malignant hyperthermia (MH) susceptibility, as well as severe myopathy. However, the mechanism by which Ca2+ leak drives these pathologies is unknown. Here, we investigate the effects of four mouse genotypes with increasingly severe RyR1 leak in skeletal muscle fibers. We find that RyR1 Ca2+ leak initiates a cascade of events that cause precise redistribution of Ca2+ among the SR, cytoplasm, and mitochondria through altering the Ca2+ permeability of the transverse tubular system membrane. This redistribution of Ca2+ allows mice with moderate RyR1 leak to maintain normal function; however, severe RyR1 leak with RYR1 mutations reduces the capacity to generate force. Our results reveal the mechanism underlying force preservation, increased ATP metabolism, and susceptibility to MH in individuals with gain-of-function RYR1 mutations.
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Affiliation(s)
- Cedric R. Lamboley
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Luke Pearce
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Crystal Seng
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Aldo Meizoso-Huesca
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Daniel P. Singh
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Barnaby P. Frankish
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Vikas Kaura
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Harriet P. Lo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Paul D. Allen
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | | | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, Australia
| | - Robyn M. Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC 3086, Australia
| | - Chris van der Poel
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC 3086, Australia
| | - Christopher J. Barclay
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bradley S. Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Corresponding author.
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