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Steczina S, Mohran S, Bailey LRJ, McMillen TS, Kooiker KB, Wood NB, Davis J, Previs MJ, Olivotto I, Pioner JM, Geeves MA, Poggesi C, Regnier M. MYBPC3-c.772G>A mutation results in haploinsufficiency and altered myosin cycling kinetics in a patient induced stem cell derived cardiomyocyte model of hypertrophic cardiomyopathy. J Mol Cell Cardiol 2024; 191:27-39. [PMID: 38648963 PMCID: PMC11116032 DOI: 10.1016/j.yjmcc.2024.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/13/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
Approximately 40% of hypertrophic cardiomyopathy (HCM) mutations are linked to the sarcomere protein cardiac myosin binding protein-C (cMyBP-C). These mutations are either classified as missense mutations or truncation mutations. One mutation whose nature has been inconsistently reported in the literature is the MYBPC3-c.772G > A mutation. Using patient-derived human induced pluripotent stem cells differentiated to cardiomyocytes (hiPSC-CMs), we have performed a mechanistic study of the structure-function relationship for this MYBPC3-c.772G > A mutation versus a mutation corrected, isogenic cell line. Our results confirm that this mutation leads to exon skipping and mRNA truncation that ultimately suggests ∼20% less cMyBP-C protein (i.e., haploinsufficiency). This, in turn, results in increased myosin recruitment and accelerated myofibril cycling kinetics. Our mechanistic studies suggest that faster ADP release from myosin is a primary cause of accelerated myofibril cross-bridge cycling due to this mutation. Additionally, the reduction in force generating heads expected from faster ADP release during isometric contractions is outweighed by a cMyBP-C phosphorylation mediated increase in myosin recruitment that leads to a net increase of myofibril force, primarily at submaximal calcium activations. These results match well with our previous report on contractile properties from myectomy samples of the patients from whom the hiPSC-CMs were generated, demonstrating that these cell lines are a good model to study this pathological mutation and extends our understanding of the mechanisms of altered contractile properties of this HCM MYBPC3-c.772G > A mutation.
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Affiliation(s)
- Sonette Steczina
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Saffie Mohran
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Logan R J Bailey
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Molecular and Cellular Biology, University of Washington, Seattle, WA 98109, USA; Department of Lab Medicine and Pathology, University of Washington, Seattle, WA 98109, USA
| | - Timothy S McMillen
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA
| | - Kristina B Kooiker
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Neil B Wood
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05404, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Lab Medicine and Pathology, University of Washington, Seattle, WA 98109, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05404, USA
| | - Iacopo Olivotto
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Italy
| | | | | | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Italy
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA.
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Lee S, Vander Roest AS, Blair CA, Kao K, Bremner SB, Childers MC, Pathak D, Heinrich P, Lee D, Chirikian O, Mohran SE, Roberts B, Smith JE, Jahng JW, Paik DT, Wu JC, Gunawardane RN, Ruppel KM, Mack DL, Pruitt BL, Regnier M, Wu SM, Spudich JA, Bernstein D. Incomplete-penetrant hypertrophic cardiomyopathy MYH7 G256E mutation causes hypercontractility and elevated mitochondrial respiration. Proc Natl Acad Sci U S A 2024; 121:e2318413121. [PMID: 38683993 PMCID: PMC11087781 DOI: 10.1073/pnas.2318413121] [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: 10/22/2023] [Accepted: 03/05/2024] [Indexed: 05/02/2024] Open
Abstract
Determining the pathogenicity of hypertrophic cardiomyopathy-associated mutations in the β-myosin heavy chain (MYH7) can be challenging due to its variable penetrance and clinical severity. This study investigates the early pathogenic effects of the incomplete-penetrant MYH7 G256E mutation on myosin function that may trigger pathogenic adaptations and hypertrophy. We hypothesized that the G256E mutation would alter myosin biomechanical function, leading to changes in cellular functions. We developed a collaborative pipeline to characterize myosin function across protein, myofibril, cell, and tissue levels to determine the multiscale effects on structure-function of the contractile apparatus and its implications for gene regulation and metabolic state. The G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 33%, resulting in more myosin heads available for contraction. Myofibrils from gene-edited MYH7WT/G256E human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) exhibited greater and faster tension development. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. We demonstrated consistent hypercontractile myosin function as a primary consequence of the MYH7 G256E mutation across scales, highlighting the pathogenicity of this gene variant. Single-cell transcriptomic and metabolic profiling demonstrated upregulated mitochondrial genes and increased mitochondrial respiration, indicating early bioenergetic alterations. This work highlights the benefit of our multiscale platform to systematically evaluate the pathogenicity of gene variants at the protein and contractile organelle level and their early consequences on cellular and tissue function. We believe this platform can help elucidate the genotype-phenotype relationships underlying other genetic cardiovascular diseases.
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Affiliation(s)
- Soah Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biopharmaceutical Convergence, Sungkyunkwan University School of Pharmacy, Suwon, Gyeonggi-do 16419 South Korea
- School of Pharmacy, Sungkyunkwan University School of Pharmacy, Suwon, Gyeonggi-do 16419, South Korea
| | - Alison S Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Cheavar A Blair
- Biological Engineering, University of California, Santa Barbara, CA 93106
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Kerry Kao
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA 98195
| | - Samantha B Bremner
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA 98195
| | - Matthew C Childers
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA 98195
| | - Divya Pathak
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Paul Heinrich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Orlando Chirikian
- Biological Engineering, University of California, Santa Barbara, CA 93106
| | - Saffie E Mohran
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA 98195
| | | | | | - James W Jahng
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - David T Paik
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305
| | | | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - David L Mack
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA 98195
| | - Beth L Pruitt
- Biological Engineering, University of California, Santa Barbara, CA 93106
| | - Michael Regnier
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA 98195
| | - Sean M Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305
| | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305
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Buvoli M, Wilson GC, Buvoli A, Gugel JF, Hau A, Bönnemann CG, Paradas C, Ryba DM, Woulfe KC, Walker LA, Buvoli T, Ochala J, Leinwand LA. A Laing distal myopathy-associated proline substitution in the β-myosin rod perturbs myosin cross-bridging activity. J Clin Invest 2024; 134:e172599. [PMID: 38690726 PMCID: PMC11060730 DOI: 10.1172/jci172599] [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: 06/22/2023] [Accepted: 03/11/2024] [Indexed: 05/03/2024] Open
Abstract
Proline substitutions within the coiled-coil rod region of the β-myosin gene (MYH7) are the predominant mutations causing Laing distal myopathy (MPD1), an autosomal dominant disorder characterized by progressive weakness of distal/proximal muscles. We report that the MDP1 mutation R1500P, studied in what we believe to be the first mouse model for the disease, adversely affected myosin motor activity despite being in the structural rod domain that directs thick filament assembly. Contractility experiments carried out on isolated mutant muscles, myofibrils, and myofibers identified muscle fatigue and weakness phenotypes, an increased rate of actin-myosin detachment, and a conformational shift of the myosin heads toward the more reactive disordered relaxed (DRX) state, causing hypercontractility and greater ATP consumption. Similarly, molecular analysis of muscle biopsies from patients with MPD1 revealed a significant increase in sarcomeric DRX content, as observed in a subset of myosin motor domain mutations causing hypertrophic cardiomyopathy. Finally, oral administration of MYK-581, a small molecule that decreases the population of heads in the DRX configuration, significantly improved the limited running capacity of the R1500P-transgenic mice and corrected the increased DRX state of the myofibrils from patients. These studies provide evidence of the molecular pathogenesis of proline rod mutations and lay the groundwork for the therapeutic advancement of myosin modulators.
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Affiliation(s)
- Massimo Buvoli
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Genevieve C.K. Wilson
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Ada Buvoli
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Jack F. Gugel
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Abbi Hau
- Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, and
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, Guy’s Campus, King’s College London, London, United Kingdom
| | - Carsten G. Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke (NINDS), NIH, Bethesda, Maryland, USA
| | - Carmen Paradas
- Neuromuscular Unit, Department of Neurology, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | | | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado, Denver, Colorado, USA
| | - Lori A. Walker
- Division of Cardiology, Department of Medicine, University of Colorado, Denver, Colorado, USA
| | - Tommaso Buvoli
- Department of Mathematics, Tulane University, New Orleans, Louisiana, USA
| | - Julien Ochala
- Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, and
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, Guy’s Campus, King’s College London, London, United Kingdom
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
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Abstract
Force generation in striated muscle is primarily controlled by structural changes in the actin-containing thin filaments triggered by an increase in intracellular calcium concentration. However, recent studies have elucidated a new class of regulatory mechanisms, based on the myosin-containing thick filament, that control the strength and speed of contraction by modulating the availability of myosin motors for the interaction with actin. This review summarizes the mechanisms of thin and thick filament activation that regulate the contractility of skeletal and cardiac muscle. A novel dual-filament paradigm of muscle regulation is emerging, in which the dynamics of force generation depends on the coordinated activation of thin and thick filaments. We highlight the interfilament signaling pathways based on titin and myosin-binding protein-C that couple thin and thick filament regulatory mechanisms. This dual-filament regulation mediates the length-dependent activation of cardiac muscle that underlies the control of the cardiac output in each heartbeat.
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Affiliation(s)
- Elisabetta Brunello
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom; ,
| | - Luca Fusi
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom; ,
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, King's College London, London, United Kingdom
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Mohran S, Steczina S, Mandrycky C, Kao K, Regnier M. Measuring the Contractile Kinetics of Isolated Myofibrils from Human-Induced Pluripotent Stem Cell Derived Cardiomyocyte (hiPSC-CM) Models of Cardiomyopathy. Methods Mol Biol 2024; 2735:213-233. [PMID: 38038851 DOI: 10.1007/978-1-0716-3527-8_12] [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] [Indexed: 12/02/2023]
Abstract
Isolated myofibrils provide biomechanical data at the contractile organelle level that are independent of cellular calcium handling and signaling pathways. These myofibrils can be harvested from animal tissue, human muscle biopsies, or stem cell-derived striated muscle. Here we present our myofibril isolation and rapid solution switching protocols, which allow for precise measurements of activation (kinetics and tension generation) and a biphasic relaxation relationship (initial slow isometric relaxation followed by a fast exponential decay in tension). This experiment is generated on a custom-built myofibril apparatus utilizing a two-photodiode array to detect micron level deflection of our forged glass tip force transducers. A complete activation/relaxation curve can be produced from a single myofibril in under 30 minutes.
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Affiliation(s)
- Saffie Mohran
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Sonette Steczina
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Christian Mandrycky
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Kerry Kao
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA.
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.
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Barefield DY, Tonino P, Woulfe KC, Rahmanseresht S, O’Leary TS, Burnham HV, Wasserstrom JA, Kirk JA, Previs MJ, Granzier HL, McNally EM. Myosin-binding protein H-like regulates myosin-binding protein distribution and function in atrial cardiomyocytes. Proc Natl Acad Sci U S A 2023; 120:e2314920120. [PMID: 38091294 PMCID: PMC10741380 DOI: 10.1073/pnas.2314920120] [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: 09/01/2023] [Accepted: 10/25/2023] [Indexed: 12/18/2023] Open
Abstract
Mutations in atrial-enriched genes can cause a primary atrial myopathy that can contribute to overall cardiovascular dysfunction. MYBPHL encodes myosin-binding protein H-like (MyBP-HL), an atrial sarcomere protein that shares domain homology with the carboxy-terminus of cardiac myosin-binding protein-C (cMyBP-C). The function of MyBP-HL and the relationship between MyBP-HL and cMyBP-C is unknown. To decipher the roles of MyBP-HL, we used structured illumination microscopy, immuno-electron microscopy, and mass spectrometry to establish the localization and stoichiometry of MyBP-HL. We found levels of cMyBP-C, a major regulator of myosin function, were half as abundant compared to levels in the ventricle. In genetic mouse models, loss of MyBP-HL doubled cMyBP-C abundance in the atria, and loss of cMyBP-C doubled MyBP-HL abundance in the atria. Structured illumination microscopy showed that both proteins colocalize in the C-zone of the A-band, with MyBP-HL enriched closer to the M-line. Immuno-electron microscopy of mouse atria showed MyBP-HL strongly localized 161 nm from the M-line, consistent with localization to the third 43 nm repeat of myosin heads. Both cMyBP-C and MyBP-HL had less-defined sarcomere localization in the atria compared to ventricle, yet areas with the expected 43 nm repeat distance were observed for both proteins. Isometric force measurements taken from control and Mybphl null single atrial myofibrils revealed that loss of Mybphl accelerated the linear phase of relaxation. These findings support a mechanism where MyBP-HL regulates cMyBP-C abundance to alter the kinetics of sarcomere relaxation in atrial sarcomeres.
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Affiliation(s)
- David Y. Barefield
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Paola Tonino
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO80045
| | - Sheema Rahmanseresht
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Hope V. Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - J. Andrew Wasserstrom
- Department of Medicine and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Jonathan A. Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Henk L. Granzier
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
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Cogliati M, Cudicio A, Benedini M, Cabral HV, Negro F, Reggiani C, Orizio C. Influence of age on force and re-lengthening dynamics after tetanic stimulation withdrawal in the tibialis anterior muscle. Eur J Appl Physiol 2023; 123:1825-1836. [PMID: 37071199 PMCID: PMC10363076 DOI: 10.1007/s00421-023-05198-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
PURPOSE During alternate movements across a joint, the changeover from one direction of rotation to the opposite may be influenced by the delay and rate of tension reduction and the compliance to re-lengthening of the previously active muscle group. Given the aging process may affect the above-mentioned factors, this work aimed to compare the dynamics of both the ankle torque decline and muscle re-lengthening, mirrored by mechanomyogram (MMG), in the tibialis anterior because of its important role in gait. METHODS During the relaxation phase, after a supramaximal 35 Hz stimulation applied at the superficial motor point, in 20 young (Y) and 20 old (O) subjects, the torque (T) and MMG dynamics characteristics were measured. RESULTS The T and MMG analysis provided: (I) the beginning of the decay after cessation of stimulation (T: 22.51 ± 5.92 ms [Y] and 51.35 ± 15.21 ms [O]; MMG: 27.38 ± 6.93 ms [Y] and 61.41 ± 18.42 ms [O]); (II) the maximum rate of reduction (T: - 110.4 ± 45.56 Nm/s [Y] and - 52.72 ± 32.12 Nm/s [O]; MMG: - 24.47 ± 10.95 mm/s [Y] and - 13.76 ± 6.54 mm/s [O]); (III) the muscle compliance, measuring the MMG reduction of every 10% reduction of torque (bin 20-10%: 15.69 ± 7.5[Y] and 10.8 ± 3.3 [O]; bin 10-0%: 22.12 ± 10.3 [Y] and 17.58 ± 5.6 [O]). CONCLUSION Muscle relaxation results are different in Y and O and can be monitored by a non-invasive method measuring physiological variables of torque and re-lengthening dynamics at the end of the electromechanical coupling previously induced by the neuromuscular stimulation.
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Affiliation(s)
- M. Cogliati
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - A. Cudicio
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - M. Benedini
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - H. V. Cabral
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - F. Negro
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
- Centre of Research on the Neuromuscular Function and the Adapted Motor Activity, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - C. Reggiani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Science and Research Center, ZRS, Koper, Slovenia
| | - C. Orizio
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
- Centre of Research on the Neuromuscular Function and the Adapted Motor Activity, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
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8
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Lee S, Roest ASV, Blair CA, Kao K, Bremner SB, Childers MC, Pathak D, Heinrich P, Lee D, Chirikian O, Mohran S, Roberts B, Smith JE, Jahng JW, Paik DT, Wu JC, Gunawardane RN, Spudich JA, Ruppel K, Mack D, Pruitt BL, Regnier M, Wu SM, Bernstein D. Multi-scale models reveal hypertrophic cardiomyopathy MYH7 G256E mutation drives hypercontractility and elevated mitochondrial respiration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.08.544276. [PMID: 37333118 PMCID: PMC10274883 DOI: 10.1101/2023.06.08.544276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Rationale Over 200 mutations in the sarcomeric protein β-myosin heavy chain (MYH7) have been linked to hypertrophic cardiomyopathy (HCM). However, different mutations in MYH7 lead to variable penetrance and clinical severity, and alter myosin function to varying degrees, making it difficult to determine genotype-phenotype relationships, especially when caused by rare gene variants such as the G256E mutation. Objective This study aims to determine the effects of low penetrant MYH7 G256E mutation on myosin function. We hypothesize that the G256E mutation would alter myosin function, precipitating compensatory responses in cellular functions. Methods We developed a collaborative pipeline to characterize myosin function at multiple scales (protein to myofibril to cell to tissue). We also used our previously published data on other mutations to compare the degree to which myosin function was altered. Results At the protein level, the G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 50.9%, suggesting more myosins available for contraction. Myofibrils isolated from hiPSC-CMs CRISPR-edited with G256E (MYH7 WT/G256E ) generated greater tension, had faster tension development and slower early phase relaxation, suggesting altered myosin-actin crossbridge cycling kinetics. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. Single-cell transcriptomic and metabolic profiling demonstrated upregulation of mitochondrial genes and increased mitochondrial respiration, suggesting altered bioenergetics as an early feature of HCM. Conclusions MYH7 G256E mutation causes structural instability in the transducer region, leading to hypercontractility across scales, perhaps from increased myosin recruitment and altered crossbridge cycling. Hypercontractile function of the mutant myosin was accompanied by increased mitochondrial respiration, while cellular hypertrophy was modest in the physiological stiffness environment. We believe that this multi-scale platform will be useful to elucidate genotype-phenotype relationships underlying other genetic cardiovascular diseases.
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9
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Dewan S, Witayavanitkul N, Kumar M, Mayer BJ, Betancourt L, Cazorla O, de Tombe PP. Depressed myocardial cross-bridge cycling kinetics in a female guinea pig model of diastolic heart failure. J Gen Physiol 2023; 155:e202213288. [PMID: 37102986 PMCID: PMC10140646 DOI: 10.1085/jgp.202213288] [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: 10/28/2022] [Revised: 02/10/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023] Open
Abstract
Cardiac hypertrophy is associated with diastolic heart failure (DHF), a syndrome in which systolic function is preserved but cardiac filling dynamics are depressed. The molecular mechanisms underlying DHF and the potential role of altered cross-bridge cycling are poorly understood. Accordingly, chronic pressure overload was induced by surgically banding the thoracic ascending aorta (AOB) in ∼400 g female Dunkin Hartley guinea pigs (AOB); Sham-operated age-matched animals served as controls. Guinea pigs were chosen to avoid the confounding impacts of altered myosin heavy chain (MHC) isoform expression seen in other small rodent models. In vivo cardiac function was assessed by echocardiography; cardiac hypertrophy was confirmed by morphometric analysis. AOB resulted in left ventricle (LV) hypertrophy and compromised diastolic function with normal systolic function. Biochemical analysis revealed exclusive expression of β-MHC isoform in both sham control and AOB LVs. Myofilament function was assessed in skinned multicellular preparations, skinned single myocyte fragments, and single myofibrils prepared from frozen (liquid N2) LVs. The rates of force-dependent ATP consumption (tension-cost) and force redevelopment (Ktr), as well as myofibril relaxation time (Timelin) were significantly blunted in AOB, indicating reduced cross-bridge cycling kinetics. Maximum Ca2+ activated force development was significantly reduced in AOB myocytes, while no change in myofilament Ca2+ sensitivity was observed. Our results indicate blunted cross-bridge cycle in a β-MHC small animal DHF model. Reduced cross-bridge cycling kinetics may contribute, at least in part, to the development of DHF in larger mammals, including humans.
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Affiliation(s)
- Sukriti Dewan
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Namthip Witayavanitkul
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Mohit Kumar
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Beth J Mayer
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Lauren Betancourt
- Phymedexp INSERM, CNRS, University of Montpellier , Montpellier, France
| | - Olivier Cazorla
- Phymedexp INSERM, CNRS, University of Montpellier , Montpellier, France
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
- Phymedexp INSERM, CNRS, University of Montpellier , Montpellier, France
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10
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Winter L, Staszewska-Daca I, Zittrich S, Elhamine F, Zrelski MM, Schmidt K, Fischer I, Jüngst C, Schauss A, Goldmann WH, Stehle R, Wiche G. Z-Disk-Associated Plectin (Isoform 1d): Spatial Arrangement, Interaction Partners, and Role in Filamin C Homeostasis. Cells 2023; 12:1259. [PMID: 37174658 PMCID: PMC10177080 DOI: 10.3390/cells12091259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/15/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Plectin, a highly versatile cytolinker protein, is crucial for myofiber integrity and function. Accordingly, mutations in the human gene (PLEC) cause several rare diseases, denoted as plectinopathies, with most of them associated with progressive muscle weakness. Of several plectin isoforms expressed in skeletal muscle and the heart, P1d is the only isoform expressed exclusively in these tissues. Using high-resolution stimulated emission depletion (STED) microscopy, here we show that plectin is located within the gaps between individual α-actinin-positive Z-disks, recruiting and bridging them to desmin intermediate filaments (Ifs). Loss of plectin in myofibril bundles led to a complete loss of desmin Ifs. Loss of Z-disk-associated plectin isoform P1d led to disorganization of muscle fibers and slower relaxation of myofibrils upon mechanical strain, in line with an observed inhomogeneity of muscle ultrastructure. In addition to binding to α-actinin and thereby providing structural support, P1d forms a scaffolding platform for the chaperone-assisted selective autophagy machinery (CASA) by directly interacting with HSC70 and synpo2. In isoform-specific knockout (P1d-KO) mouse muscle and mechanically stretched plectin-deficient myoblasts, we found high levels of undigested filamin C, a bona fide substrate of CASA. Similarly, subjecting P1d-KO mice to forced swim tests led to accumulation of filamin C aggregates in myofibers, highlighting a specific role of P1d in tension-induced proteolysis activated upon high loads of physical exercise and muscle contraction.
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Affiliation(s)
- Lilli Winter
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
- Division of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Ilona Staszewska-Daca
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Stefan Zittrich
- Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Fatiha Elhamine
- Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Michaela M. Zrelski
- Division of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Katy Schmidt
- Division of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
- Core Facility for Cell Imaging & Ultrastructure Research (CIUS), University of Vienna, 1030 Vienna, Austria
| | - Irmgard Fischer
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Christian Jüngst
- CECAD Imaging Facility, CECAD Forschungszentrum Cologne, 50931 Cologne, Germany
| | - Astrid Schauss
- CECAD Imaging Facility, CECAD Forschungszentrum Cologne, 50931 Cologne, Germany
| | - Wolfgang H. Goldmann
- Department of Physics, Center for Medical Physics and Technology, Friedrich-Alexander-University Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Robert Stehle
- Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Gerhard Wiche
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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11
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Pioner JM, Vitale G, Steczina S, Langione M, Margara F, Santini L, Giardini F, Lazzeri E, Piroddi N, Scellini B, Palandri C, Schuldt M, Spinelli V, Girolami F, Mazzarotto F, van der Velden J, Cerbai E, Tesi C, Olivotto I, Bueno-Orovio A, Sacconi L, Coppini R, Ferrantini C, Regnier M, Poggesi C. Slower Calcium Handling Balances Faster Cross-Bridge Cycling in Human MYBPC3 HCM. Circ Res 2023; 132:628-644. [PMID: 36744470 PMCID: PMC9977265 DOI: 10.1161/circresaha.122.321956] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 01/19/2023] [Accepted: 01/24/2023] [Indexed: 02/07/2023]
Abstract
BACKGROUND The pathogenesis of MYBPC3-associated hypertrophic cardiomyopathy (HCM) is still unresolved. In our HCM patient cohort, a large and well-characterized population carrying the MYBPC3:c772G>A variant (p.Glu258Lys, E258K) provides the unique opportunity to study the basic mechanisms of MYBPC3-HCM with a comprehensive translational approach. METHODS We collected clinical and genetic data from 93 HCM patients carrying the MYBPC3:c772G>A variant. Functional perturbations were investigated using different biophysical techniques in left ventricular samples from 4 patients who underwent myectomy for refractory outflow obstruction, compared with samples from non-failing non-hypertrophic surgical patients and healthy donors. Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and engineered heart tissues (EHTs) were also investigated. RESULTS Haplotype analysis revealed MYBPC3:c772G>A as a founder mutation in Tuscany. In ventricular myocardium, the mutation leads to reduced cMyBP-C (cardiac myosin binding protein-C) expression, supporting haploinsufficiency as the main primary disease mechanism. Mechanical studies in single myofibrils and permeabilized muscle strips highlighted faster cross-bridge cycling, and higher energy cost of tension generation. A novel approach based on tissue clearing and advanced optical microscopy supported the idea that the sarcomere energetics dysfunction is intrinsically related with the reduction in cMyBP-C. Studies in single cardiomyocytes (native and hiPSC-derived), intact trabeculae and hiPSC-EHTs revealed prolonged action potentials, slower Ca2+ transients and preserved twitch duration, suggesting that the slower excitation-contraction coupling counterbalanced the faster sarcomere kinetics. This conclusion was strengthened by in silico simulations. CONCLUSIONS HCM-related MYBPC3:c772G>A mutation invariably impairs sarcomere energetics and cross-bridge cycling. Compensatory electrophysiological changes (eg, reduced potassium channel expression) appear to preserve twitch contraction parameters, but may expose patients to greater arrhythmic propensity and disease progression. Therapeutic approaches correcting the primary sarcomeric defects may prevent secondary cardiomyocyte remodeling.
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Affiliation(s)
- Josè Manuel Pioner
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
- Department of Biology (J.M.P.), University of Florence, Italy
| | - Giulia Vitale
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
| | - Sonette Steczina
- Department of Bioengineering, University of Washington, Seattle, WA (S.S., M.R.)
| | - Marianna Langione
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
| | - Francesca Margara
- Department of Computer Science, University of Oxford, United Kingdom (F. Margara, A.B.-O.)
| | - Lorenzo Santini
- Department of NeuroFarBa (L. Santini, C. Palandri, V. Spinelli, E. Cerbai, R. Coppini), University of Florence, Italy
| | - Francesco Giardini
- European Laboratory for Non-Linear Spectroscopy (LENS) (F. Giardini, E. Lazzeri, C.F., C.P., E. Cerbai), University of Florence, Italy
| | - Erica Lazzeri
- European Laboratory for Non-Linear Spectroscopy (LENS) (F. Giardini, E. Lazzeri, C.F., C.P., E. Cerbai), University of Florence, Italy
| | - Nicoletta Piroddi
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
| | - Beatrice Scellini
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
| | - Chiara Palandri
- Department of NeuroFarBa (L. Santini, C. Palandri, V. Spinelli, E. Cerbai, R. Coppini), University of Florence, Italy
| | - Maike Schuldt
- Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Physiology, The Netherlands (M.S., J.v.d.V.)
| | - Valentina Spinelli
- Department of NeuroFarBa (L. Santini, C. Palandri, V. Spinelli, E. Cerbai, R. Coppini), University of Florence, Italy
| | - Francesca Girolami
- Pediatric Cardiology (F. Girolami), IRCCS Meyer Children’s Hospital, Florence, Italy
| | - Francesco Mazzarotto
- Department of Molecular and Translational Medicine, University of Brescia, Italy (F. Mazzarotto)
- National Heart and Lung Institute, Imperial College London, London, United Kingdom (F. Mazzarotto)
| | - Jolanda van der Velden
- Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Physiology, The Netherlands (M.S., J.v.d.V.)
| | - Elisabetta Cerbai
- Department of NeuroFarBa (L. Santini, C. Palandri, V. Spinelli, E. Cerbai, R. Coppini), University of Florence, Italy
- European Laboratory for Non-Linear Spectroscopy (LENS) (F. Giardini, E. Lazzeri, C.F., C.P., E. Cerbai), University of Florence, Italy
| | - Chiara Tesi
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
| | - Iacopo Olivotto
- Cardiogenetics Unit (I.O.), IRCCS Meyer Children’s Hospital, Florence, Italy
- Referral Center for Cardiomyopathies, Careggi University Hospital, Florence, Italy (I.O.)
| | - Alfonso Bueno-Orovio
- Department of Computer Science, University of Oxford, United Kingdom (F. Margara, A.B.-O.)
| | - Leonardo Sacconi
- Institute of Clinical Physiology (IFC), National Research Council, Florence, Italy (L. Sacconi)
- Institute for Experimental Cardiovascular Medicine, Faculty of Medicine, University of Freiburg (L. Sacconi)
| | - Raffaele Coppini
- Department of NeuroFarBa (L. Santini, C. Palandri, V. Spinelli, E. Cerbai, R. Coppini), University of Florence, Italy
| | - Cecilia Ferrantini
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
- European Laboratory for Non-Linear Spectroscopy (LENS) (F. Giardini, E. Lazzeri, C.F., C.P., E. Cerbai), University of Florence, Italy
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA (S.S., M.R.)
| | - Corrado Poggesi
- Department of Clinical and Experimental Medicine, Division of Physiology (J.M.P., G.V., M.L., N.P., B.S., C.T., C.F., C. Poggesi), University of Florence, Italy
- European Laboratory for Non-Linear Spectroscopy (LENS) (F. Giardini, E. Lazzeri, C.F., C.P., E. Cerbai), University of Florence, Italy
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12
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Baraldo M, Zorzato S, Dondjang AHT, Geremia A, Nogara L, Dumitras AG, Canato M, Marcucci L, Nolte H, Blaauw B. Inducible deletion of raptor and mTOR from adult skeletal muscle impairs muscle contractility and relaxation. J Physiol 2022; 600:5055-5075. [PMID: 36255030 DOI: 10.1113/jp283686] [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] [Received: 08/04/2022] [Accepted: 09/20/2022] [Indexed: 01/05/2023] Open
Abstract
Skeletal muscle weakness has been associated with different pathological conditions, including sarcopenia and muscular dystrophy, and is accompanied by altered mammalian target of rapamycin (mTOR) signalling. We wanted to elucidate the functional role of mTOR in muscle contractility. Most loss-of-function studies for mTOR signalling have used the drug rapamycin to inhibit some of the signalling downstream of mTOR. However, given that rapamycin does not inhibit all mTOR signalling completely, we generated a double knockout for mTOR and for the scaffold protein of mTORC1, raptor, in skeletal muscle. We found that double knockout in mice results in a more severe phenotype compared with deletion of raptor or mTOR alone. Indeed, these animals display muscle weakness, increased fibre denervation and a slower muscle relaxation following tetanic stimulation. This is accompanied by a shift towards slow-twitch fibres and changes in the expression levels of calcium-related genes, such as Serca1 and Casq1. Double knockout mice show a decrease in calcium decay kinetics after tetanus in vivo, suggestive of a reduced calcium reuptake. In addition, RNA sequencing analysis revealed that many downregulated genes, such as Tcap and Fhod3, are linked to sarcomere organization. These results suggest a key role for mTOR signalling in maintaining proper fibre relaxation in skeletal muscle. KEY POINTS: Skeletal muscle wasting and weakness have been associated with different pathological conditions, including sarcopenia and muscular dystrophy, and are accompanied by altered mammalian target of rapamycin (mTOR) signalling. Mammalian target of rapamycin plays a crucial role in the maintenance of muscle mass and functionality. We found that the loss of both mTOR and raptor results in contractile abnormalities, with severe muscle weakness and delayed relaxation following tetanic stimulation. These results are associated with alterations in the expression of genes involved in sarcomere organization and calcium handling and with an impairment in calcium reuptake after contraction. Taken together, these results provide a mechanistic insight into the role of mTOR in muscle contractility.
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Affiliation(s)
- Martina Baraldo
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Sabrina Zorzato
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Achille Homère Tchampda Dondjang
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Alessia Geremia
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Leonardo Nogara
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ana Georgia Dumitras
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marta Canato
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Center for Biosystems Dynamics Research, RIKEN, Suita, Japan
| | - Hendrik Nolte
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
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13
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Lin YH, Major JL, Liebner T, Hourani Z, Travers JG, Wennersten SA, Haefner KR, Cavasin MA, Wilson CE, Jeong MY, Han Y, Gotthardt M, Ferguson SK, Ambardekar AV, Lam MP, Choudhary C, Granzier HL, Woulfe KC, McKinsey TA. HDAC6 modulates myofibril stiffness and diastolic function of the heart. J Clin Invest 2022; 132:e148333. [PMID: 35575093 PMCID: PMC9106344 DOI: 10.1172/jci148333] [Citation(s) in RCA: 12] [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: 02/03/2021] [Accepted: 04/05/2022] [Indexed: 01/26/2023] Open
Abstract
Passive stiffness of the heart is determined largely by extracellular matrix and titin, which functions as a molecular spring within sarcomeres. Titin stiffening is associated with the development of diastolic dysfunction (DD), while augmented titin compliance appears to impair systolic performance in dilated cardiomyopathy. We found that myofibril stiffness was elevated in mice lacking histone deacetylase 6 (HDAC6). Cultured adult murine ventricular myocytes treated with a selective HDAC6 inhibitor also exhibited increased myofibril stiffness. Conversely, HDAC6 overexpression in cardiomyocytes led to decreased myofibril stiffness, as did ex vivo treatment of mouse, rat, and human myofibrils with recombinant HDAC6. Modulation of myofibril stiffness by HDAC6 was dependent on 282 amino acids encompassing a portion of the PEVK element of titin. HDAC6 colocalized with Z-disks, and proteomics analysis suggested that HDAC6 functions as a sarcomeric protein deacetylase. Finally, increased myofibril stiffness in HDAC6-deficient mice was associated with exacerbated DD in response to hypertension or aging. These findings define a role for a deacetylase in the control of myofibril function and myocardial passive stiffness, suggest that reversible acetylation alters titin compliance, and reveal the potential of targeting HDAC6 to manipulate the elastic properties of the heart to treat cardiac diseases.
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Affiliation(s)
- Ying-Hsi Lin
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jennifer L. Major
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Tim Liebner
- Department of Proteomics, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zaynab Hourani
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, USA
| | - Joshua G. Travers
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Sara A. Wennersten
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Korey R. Haefner
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Maria A. Cavasin
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | | | | | - Yu Han
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Scott K. Ferguson
- Cardiovascular and Pulmonary Research Laboratory, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Amrut V. Ambardekar
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Maggie P.Y. Lam
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Chunaram Choudhary
- Department of Proteomics, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henk L. Granzier
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, USA
| | | | - Timothy A. McKinsey
- Department of Medicine, Division of Cardiology, and
- Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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14
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Knight WE, Woulfe KC. Dysfunctional sarcomeric relaxation in the heart. CURRENT OPINION IN PHYSIOLOGY 2022; 26:100535. [PMID: 35603011 PMCID: PMC9119547 DOI: 10.1016/j.cophys.2022.100535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Since cardiac relaxation is commonly impaired in heart failure caused by many different etiologies, identifying druggable targets is a common goal. While many factors contribute to cardiac relaxation, this review focuses on sarcomeric relaxation and dysfunction. Any alteration in how sarcomeric proteins interact can lead to significant shifts in sarcomeric relaxation that may contribute to diastolic dysfunction. Considering examples of sarcomeric dysfunction that have been reported in 3 different pathologies, hypertrophic cardiomyopathy, restrictive cardiomyopathy, and heart failure with preserved ejection fraction, will provide insights into the role sarcomeric dysfunction plays in impaired cardiac relaxation. This will ultimately improve our understanding of sarcomeric physiology and uncover new therapeutic targets.
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Affiliation(s)
- Walter E. Knight
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, 12700 E 19 Ave, Aurora, CO 80045
| | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, 12700 E 19 Ave, Aurora, CO 80045
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15
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Lewalle A, Campbell KS, Campbell SG, Milburn GN, Niederer SA. Functional and structural differences between skinned and intact muscle preparations. J Gen Physiol 2022; 154:e202112990. [PMID: 35045156 PMCID: PMC8929306 DOI: 10.1085/jgp.202112990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 12/16/2021] [Indexed: 11/20/2022] Open
Abstract
Myofilaments and their associated proteins, which together constitute the sarcomeres, provide the molecular-level basis for contractile function in all muscle types. In intact muscle, sarcomere-level contraction is strongly coupled to other cellular subsystems, in particular the sarcolemmal membrane. Skinned muscle preparations (where the sarcolemma has been removed or permeabilized) are an experimental system designed to probe contractile mechanisms independently of the sarcolemma. Over the last few decades, experiments performed using permeabilized preparations have been invaluable for clarifying the understanding of contractile mechanisms in both skeletal and cardiac muscle. Today, the technique is increasingly harnessed for preclinical and/or pharmacological studies that seek to understand how interventions will impact intact muscle contraction. In this context, intrinsic functional and structural differences between skinned and intact muscle pose a major interpretational challenge. This review first surveys measurements that highlight these differences in terms of the sarcomere structure, passive and active tension generation, and calcium dependence. We then highlight the main practical challenges and caveats faced by experimentalists seeking to emulate the physiological conditions of intact muscle. Gaining an awareness of these complexities is essential for putting experiments in due perspective.
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Affiliation(s)
- Alex Lewalle
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | - Kenneth S. Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY
| | - Stuart G. Campbell
- Departments of Biomedical Engineering and Cellular and Molecular Physiology, Yale University, New Haven, CT
| | - Gregory N. Milburn
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY
| | - Steven A. Niederer
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
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16
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Smith QM, Inchingolo AV, Mihailescu MD, Dai H, Kad NM. Single-molecule imaging reveals the concerted release of myosin from regulated thin filaments. eLife 2021; 10:69184. [PMID: 34569933 PMCID: PMC8476120 DOI: 10.7554/elife.69184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 09/11/2021] [Indexed: 11/13/2022] Open
Abstract
Regulated thin filaments (RTFs) tightly control striated muscle contraction through calcium binding to troponin, which enables tropomyosin to expose myosin-binding sites on actin. Myosin binding holds tropomyosin in an open position, exposing more myosin-binding sites on actin, leading to cooperative activation. At lower calcium levels, troponin and tropomyosin turn off the thin filament; however, this is antagonised by the high local concentration of myosin, questioning how the thin filament relaxes. To provide molecular details of deactivation, we used single-molecule imaging of green fluorescent protein (GFP)-tagged myosin-S1 (S1-GFP) to follow the activation of RTF tightropes. In sub-maximal activation conditions, RTFs are not fully active, enabling direct observation of deactivation in real time. We observed that myosin binding occurs in a stochastic step-wise fashion; however, an unexpectedly large probability of multiple contemporaneous detachments is observed. This suggests that deactivation of the thin filament is a coordinated active process.
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Affiliation(s)
- Quentin M Smith
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | | | | | - Hongsheng Dai
- Department of Mathematical Sciences, University of Essex, Colchester, United Kingdom
| | - Neil M Kad
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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17
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Hill C, Brunello E, Fusi L, Ovejero JG, Irving M. Myosin-based regulation of twitch and tetanic contractions in mammalian skeletal muscle. eLife 2021; 10:e68211. [PMID: 34121660 PMCID: PMC8275128 DOI: 10.7554/elife.68211] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/11/2021] [Indexed: 01/16/2023] Open
Abstract
Time-resolved X-ray diffraction of isolated fast-twitch muscles of mice was used to show how structural changes in the myosin-containing thick filaments contribute to the regulation of muscle contraction, extending the previous focus on regulation by the actin-containing thin filaments. This study shows that muscle activation involves the following sequence of structural changes: thin filament activation, disruption of the helical array of myosin motors characteristic of resting muscle, release of myosin motor domains from the folded conformation on the filament backbone, and actin attachment. Physiological force generation in the 'twitch' response of skeletal muscle to single action potential stimulation is limited by incomplete activation of the thick filament and the rapid inactivation of both filaments. Muscle relaxation after repetitive stimulation is accompanied by a complete recovery of the folded motor conformation on the filament backbone but by incomplete reformation of the helical array, revealing a structural basis for post-tetanic potentiation in isolated muscles.
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Affiliation(s)
- Cameron Hill
- Randall Centre for Cell & Molecular Biophysics, New Hunt’s House, Guy’s Campus, King’s College LondonLondonUnited Kingdom
| | - Elisabetta Brunello
- Randall Centre for Cell & Molecular Biophysics, New Hunt’s House, Guy’s Campus, King’s College LondonLondonUnited Kingdom
| | - Luca Fusi
- Randall Centre for Cell & Molecular Biophysics, New Hunt’s House, Guy’s Campus, King’s College LondonLondonUnited Kingdom
| | - Jesús G Ovejero
- Randall Centre for Cell & Molecular Biophysics, New Hunt’s House, Guy’s Campus, King’s College LondonLondonUnited Kingdom
| | - Malcolm Irving
- Randall Centre for Cell & Molecular Biophysics, New Hunt’s House, Guy’s Campus, King’s College LondonLondonUnited Kingdom
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18
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Scellini B, Piroddi N, Dente M, Vitale G, Pioner JM, Coppini R, Ferrantini C, Poggesi C, Tesi C. Mavacamten has a differential impact on force generation in myofibrils from rabbit psoas and human cardiac muscle. J Gen Physiol 2021; 153:212024. [PMID: 33891673 PMCID: PMC8077167 DOI: 10.1085/jgp.202012789] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 03/04/2021] [Accepted: 03/30/2021] [Indexed: 12/20/2022] Open
Abstract
Mavacamten (MYK-461) is a small-molecule allosteric inhibitor of sarcomeric myosins being used in preclinical/clinical trials for hypertrophic cardiomyopathy treatment. A better understanding of its impact on force generation in intact or skinned striated muscle preparations, especially for human cardiac muscle, has been hindered by diffusional barriers. These limitations have been overcome by mechanical experiments using myofibrils subject to perturbations of the contractile environment by sudden solution changes. Here, we characterize the action of mavacamten in human ventricular myofibrils compared with fast skeletal myofibrils from rabbit psoas. Mavacamten had a fast, fully reversible, and dose-dependent negative effect on maximal Ca2+-activated isometric force at 15°C, which can be explained by a sudden decrease in the number of heads functionally available for interaction with actin. It also decreased the kinetics of force development in fast skeletal myofibrils, while it had no effect in human ventricular myofibrils. For both myofibril types, the effects of mavacamten were independent from phosphate in the low-concentration range. Mavacamten did not alter force relaxation of fast skeletal myofibrils, but it significantly accelerated the relaxation of human ventricular myofibrils. Lastly, mavacamten had no effect on resting tension but inhibited the ADP-stimulated force in the absence of Ca2+. Altogether, these effects outline a motor isoform-specific dependence of the inhibitory effect of mavacamten on force generation, which is mediated by a reduction in the availability of strongly actin-binding heads. Mavacamten may thus alter the interplay between thick and thin filament regulation mechanisms of contraction in association with the widely documented drug effect of stabilizing myosin motor heads into autoinhibited states.
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Affiliation(s)
- Beatrice Scellini
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Marica Dente
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Giulia Vitale
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Josè Manuel Pioner
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Raffaele Coppini
- Department of Neuroscience, Psychology, Drug Sciences, and Child Health, University of Florence, Florence, Italy
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
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19
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Solís C, Solaro RJ. Novel insights into sarcomere regulatory systems control of cardiac thin filament activation. J Gen Physiol 2021; 153:211903. [PMID: 33740037 PMCID: PMC7988513 DOI: 10.1085/jgp.202012777] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/23/2021] [Indexed: 12/11/2022] Open
Abstract
Our review focuses on sarcomere regulatory mechanisms with a discussion of cardiac-specific modifications to the three-state model of thin filament activation from a blocked to closed to open state. We discuss modulation of these thin filament transitions by Ca2+, by crossbridge interactions, and by thick filament–associated proteins, cardiac myosin–binding protein C (cMyBP-C), cardiac regulatory light chain (cRLC), and titin. Emerging evidence supports the idea that the cooperative activation of the thin filaments despite a single Ca2+ triggering regulatory site on troponin C (cTnC) cannot be considered in isolation of other functional domains of the sarcomere. We discuss long- and short-range interactions among these domains with the regulatory units of thin filaments, including proteins at the barbed end at the Z-disc and the pointed end near the M-band. Important to these discussions is the ever-increasing understanding of the role of cMyBP-C, cRLC, and titin filaments. Detailed knowledge of these control processes is critical to the understanding of mechanisms sustaining physiological cardiac state with varying hemodynamic load, to better defining genetic and acquired cardiac disorders, and to developing targets for therapies at the level of the sarcomeres.
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Affiliation(s)
- Christopher Solís
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
| | - R John Solaro
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
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20
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Kawai M, Stehle R, Pfitzer G, Iorga B. Phosphate has dual roles in cross-bridge kinetics in rabbit psoas single myofibrils. J Gen Physiol 2021; 153:211791. [PMID: 33599680 PMCID: PMC7885270 DOI: 10.1085/jgp.202012755] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 12/04/2020] [Accepted: 01/15/2021] [Indexed: 11/27/2022] Open
Abstract
In this study, we aimed to study the role of inorganic phosphate (Pi) in the production of oscillatory work and cross-bridge (CB) kinetics of striated muscle. We applied small-amplitude sinusoidal length oscillations to rabbit psoas single myofibrils and muscle fibers, and the resulting force responses were analyzed during maximal Ca2+ activation (pCa 4.65) at 15°C. Three exponential processes, A, B, and C, were identified from the tension transients, which were studied as functions of Pi concentration ([Pi]). In myofibrils, we found that process C, corresponding to phase 2 of step analysis during isometric contraction, is almost a perfect single exponential function compared with skinned fibers, which exhibit distributed rate constants, as described previously. The [Pi] dependence of the apparent rate constants 2πb and 2πc, and that of isometric tension, was studied to characterize the force generation and Pi release steps in the CB cycle, as well as the inhibitory effect of Pi. In contrast to skinned fibers, Pi does not accumulate in the core of myofibrils, allowing sinusoidal analysis to be performed nearly at [Pi] = 0. Process B disappeared as [Pi] approached 0 mM in myofibrils, indicating the significance of the role of Pi rebinding to CBs in the production of oscillatory work (process B). Our results also suggest that Pi competitively inhibits ATP binding to CBs, with an inhibitory dissociation constant of ∼2.6 mM. Finally, we found that the sinusoidal waveform of tension is mostly distorted by second harmonics and that this distortion is closely correlated with production of oscillatory work, indicating that the mechanism of generating force is intrinsically nonlinear. A nonlinear force generation mechanism suggests that the length-dependent intrinsic rate constant is asymmetric upon stretch and release and that there may be a ratchet mechanism involved in the CB cycle.
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Affiliation(s)
- Masataka Kawai
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA
| | - Robert Stehle
- Institute of Vegetative Physiology, University of Köln, Köln, Germany
| | - Gabriele Pfitzer
- Institute of Vegetative Physiology, University of Köln, Köln, Germany.,Institute of Neurophysiology, University of Köln, Köln, Germany
| | - Bogdan Iorga
- Institute of Vegetative Physiology, University of Köln, Köln, Germany.,Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany.,Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
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21
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Mijailovich SM, Prodanovic M, Poggesi C, Powers JD, Davis J, Geeves MA, Regnier M. The effect of variable troponin C mutation thin filament incorporation on cardiac muscle twitch contractions. J Mol Cell Cardiol 2021; 155:112-124. [PMID: 33636222 DOI: 10.1016/j.yjmcc.2021.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 11/19/2022]
Abstract
One of the complexities of understanding the pathology of familial forms of cardiac diseases is the level of mutation incorporation in sarcomeres. Computational models of the sarcomere that are spatially explicit offer an approach to study aspects of mutational incorporation into myofilaments that are more challenging to get at experimentally. We studied two well characterized mutations of cardiac TnC, L48Q and I61Q, that decrease or increase the release rate of Ca2+ from cTnC, k-Ca, resulting in HCM and DCM respectively [1]. Expression of these mutations in transgenic mice was used to provide experimental data for incorporation of 30 and 50% (respectively) into sarcomeres. Here we demonstrate that fixed length twitch contractions of trabeculae from mice containing mutant differ from WT; L48Q trabeculae have slower relaxation while I61Q trabeculae have markedly reduced peak tension. Using our multiscale modelling approach [2] we were able to describe the tension transients of WT mouse myocardium. Tension transients for the mutant cTnCs were simulated with changes in k-Ca, measured experimentally for each cTnC mutant in whole troponin complex, a change in the affinity of cTnC for cTnI, and a reduction in the number of detached crossbridges available for binding. A major advantage of the multiscale explicit 3-D model is that it predicts the effects of variable mutation incorporation, and the effects of variations in mutation distribution within thin filaments in sarcomeres. Such effects are currently impossible to explore experimentally. We explored random and clustered distributions of mutant cTnCs in thin filaments, as well as distributions of individual thin filaments with only WT or mutant cTnCs present. The effects of variable amounts of incorporation and non-random distribution of mutant cTnCs are more marked for I61Q than L48Q cTnC. We conclude that this approach can be effective for study on mutations in multiple proteins of the sarcomere. SUMMARY: A challenge in experimental studies of diseases is accounting for the effect of variable mutation incorporation into myofilaments. Here we use a spatially explicit computational approach, informed by experimental data from transgenic mice expressing one of two mutations in cardiac Troponin C that increase or decrease calcium sensitivity. We demonstrate that the model can accurately describe twitch contractions for the data and go on to explore the effect of variable mutant incorporation and localization on simulated cardiac muscle twitches.
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Affiliation(s)
| | - Momcilo Prodanovic
- Bioengineering Research and Development Center (BioIRC), Kragujevac 34000, Serbia; Faculty of Engineering, University of Kragujevac, Kragujevac 34000, Serbia
| | - Corrado Poggesi
- Department of Experimental & Clinical Medicine, University of Florence, Florence 50134, Italy
| | - Joseph D Powers
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA; Dept. of Bioengineering, University of California, San Diego, CA 92093, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Michael A Geeves
- Dept. of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
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22
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Piroddi N, Pesce P, Scellini B, Manzini S, Ganzetti GS, Badi I, Menegollo M, Cora V, Tiso S, Cinquetti R, Monti L, Chiesa G, Bleyl SB, Busnelli M, Dellera F, Bruno D, Caicci F, Grimaldi A, Taramelli R, Manni L, Sacerdoti D, Tesi C, Poggesi C, Ausoni S, Acquati F, Campione M. Myocardial overexpression of ANKRD1 causes sinus venosus defects and progressive diastolic dysfunction. Cardiovasc Res 2021; 116:1458-1472. [PMID: 31688894 DOI: 10.1093/cvr/cvz291] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 09/26/2019] [Accepted: 10/30/2019] [Indexed: 12/11/2022] Open
Abstract
AIMS Increased Ankyrin Repeat Domain 1 (ANKRD1) levels linked to gain of function mutations have been associated to total anomalous pulmonary venous return and adult cardiomyopathy occurrence in humans. The link between increased ANKRD1 level and cardiac structural and functional disease is not understood. To get insight into this problem, we have generated a gain of function ANKRD1 mouse model by overexpressing ANKRD1 in the myocardium. METHODS AND RESULTS Ankrd1 is expressed non-homogeneously in the embryonic myocardium, with a dynamic nucleo-sarcomeric localization in developing cardiomyocytes. ANKRD1 transgenic mice present sinus venosus defect, which originates during development by impaired remodelling of early embryonic heart. Adult transgenic hearts develop diastolic dysfunction with preserved ejection fraction, which progressively evolves into heart failure, as shown histologically and haemodynamically. Transgenic cardiomyocyte structure, sarcomeric assembly, and stability are progressively impaired from embryonic to adult life. Postnatal transgenic myofibrils also present characteristic functional alterations: impaired compliance at neonatal stage and impaired lusitropism in adult hearts. Altogether, our combined analyses suggest that impaired embryonic remodelling and adult heart dysfunction in ANKRD1 transgenic mice present a common ground of initial cardiomyocyte defects, which are exacerbated postnatally. Molecular analysis showed transient activation of GATA4-Nkx2.5 transcription in early transgenic embryos and subsequent dynamic transcriptional modulation within titin gene. CONCLUSIONS ANKRD1 is a fine mediator of cardiomyocyte response to haemodynamic load in the developing and adult heart. Increased ANKRD1 levels are sufficient to initiate an altered cellular phenotype, which is progressively exacerbated into a pathological organ response by the high ventricular workload during postnatal life. Our study defines for the first time a unifying picture for ANKRD1 role in heart development and disease and provides the first mechanistic link between ANKRD1 overexpression and cardiac disease onset.
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Affiliation(s)
- Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Paola Pesce
- Department of Medicine, University of Padua, 35121 Padua, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Stefano Manzini
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy
| | - Giulia S Ganzetti
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy
| | - Ileana Badi
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy.,Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Michela Menegollo
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Virginia Cora
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Simone Tiso
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Raffaella Cinquetti
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Laura Monti
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Giulia Chiesa
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy
| | - Steven B Bleyl
- Department of Pediatrics, University of Utah, Salt Lake City, 84132 UT, USA
| | - Marco Busnelli
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy
| | - Federica Dellera
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy
| | - Daniele Bruno
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Federico Caicci
- Department of Biology, University of Padua, 35121 Padua, Italy
| | - Annalisa Grimaldi
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Roberto Taramelli
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Lucia Manni
- Department of Biology, University of Padua, 35121 Padua, Italy
| | - David Sacerdoti
- Department of Medicine, University of Padua, 35121 Padua, Italy
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Simonetta Ausoni
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Francesco Acquati
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Marina Campione
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy.,CNR-Neuroscience Institute, 35121 Padua, Italy
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23
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Knight WE, Ali HR, Nakano SJ, Wilson CE, Walker LA, Woulfe KC. Ex vivo Methods for Measuring Cardiac Muscle Mechanical Properties. Front Physiol 2021; 11:616996. [PMID: 33488406 PMCID: PMC7820907 DOI: 10.3389/fphys.2020.616996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/10/2020] [Indexed: 11/13/2022] Open
Abstract
Cardiovascular disease continues to be the leading cause of morbidity and mortality in the United States and thousands of manuscripts each year are aimed at elucidating mechanisms underlying cardiac disease. The methods for quantifying cardiac performance are quite varied, with each technique assessing unique features of cardiac muscle mechanical properties. Accordingly, in this review, we discuss current ex vivo methods for quantifying cardiac muscle performance, highlighting what can be learned from each method, and how each technique can be used in conjunction to complement others for a more comprehensive understanding of cardiac function. Importantly, cardiac function can be assessed at several different levels, from the whole organ down to individual protein-protein interactions. Here, we take a reductionist view of methods that are commonly used to measure the distinct aspects of cardiac mechanical function, beginning with whole heart preparations and finishing with the in vitro motility assay. While each of the techniques are individually well-documented in the literature, there is a significant need for a comparison of the techniques, delineating the mechanical parameters that can are best measured with each technique, as well as the strengths and weaknesses inherent to each method. Additionally, we will consider complementary techniques and how these methods can be used in combination to improve our understanding of cardiac mechanical function. By presenting each of these methods, with their strengths and limitations, in a single manuscript, this review will assist cardiovascular biologists in understanding the existing literature on cardiac mechanical function, as well as designing future experiments.
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Affiliation(s)
- Walter E Knight
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Hadi R Ali
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Stephanie J Nakano
- Department of Pediatrics, Division of Cardiology, Children's Hospital, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Cortney E Wilson
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Lori A Walker
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Kathleen C Woulfe
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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24
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Alpha and beta myosin isoforms and human atrial and ventricular contraction. Cell Mol Life Sci 2021; 78:7309-7337. [PMID: 34704115 PMCID: PMC8629898 DOI: 10.1007/s00018-021-03971-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 01/15/2023]
Abstract
Human atrial and ventricular contractions have distinct mechanical characteristics including speed of contraction, volume of blood delivered and the range of pressure generated. Notably, the ventricle expresses predominantly β-cardiac myosin while the atrium expresses mostly the α-isoform. In recent years exploration of the properties of pure α- & β-myosin isoforms have been possible in solution, in isolated myocytes and myofibrils. This allows us to consider the extent to which the atrial vs ventricular mechanical characteristics are defined by the myosin isoform expressed, and how the isoform properties are matched to their physiological roles. To do this we Outline the essential feature of atrial and ventricular contraction; Explore the molecular structural and functional characteristics of the two myosin isoforms; Describe the contractile behaviour of myocytes and myofibrils expressing a single myosin isoform; Finally we outline the outstanding problems in defining the differences between the atria and ventricles. This allowed us consider what features of contraction can and cannot be ascribed to the myosin isoforms present in the atria and ventricles.
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25
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Hypothesis: Single Actomyosin Properties Account for Ensemble Behavior in Active Muscle Shortening and Isometric Contraction. Int J Mol Sci 2020; 21:ijms21218399. [PMID: 33182367 PMCID: PMC7664901 DOI: 10.3390/ijms21218399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 11/17/2022] Open
Abstract
Muscle contraction results from cyclic interactions between myosin II motors and actin with two sets of proteins organized in overlapping thick and thin filaments, respectively, in a nearly crystalline lattice in a muscle sarcomere. However, a sarcomere contains a huge number of other proteins, some with important roles in muscle contraction. In particular, these include thin filament proteins, troponin and tropomyosin; thick filament proteins, myosin binding protein C; and the elastic protein, titin, that connects the thin and thick filaments. Furthermore, the order and 3D organization of the myofilament lattice may be important per se for contractile function. It is possible to model muscle contraction based on actin and myosin alone with properties derived in studies using single molecules and biochemical solution kinetics. It is also possible to reproduce several features of muscle contraction in experiments using only isolated actin and myosin, arguing against the importance of order and accessory proteins. Therefore, in this paper, it is hypothesized that “single molecule actomyosin properties account for the contractile properties of a half sarcomere during shortening and isometric contraction at almost saturating Ca concentrations”. In this paper, existing evidence for and against this hypothesis is reviewed and new modeling results to support the arguments are presented. Finally, further experimental tests are proposed, which if they corroborate, at least approximately, the hypothesis, should significantly benefit future effective analysis of a range of experimental studies, as well as drug discovery efforts.
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26
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Vernillo G, Khassetarash A, Millet GY, Temesi J. Use of transcranial magnetic stimulation to assess relaxation rates in unfatigued and fatigued knee-extensor muscles. Exp Brain Res 2020; 239:205-216. [PMID: 33140192 PMCID: PMC7884370 DOI: 10.1007/s00221-020-05921-9] [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: 06/28/2020] [Accepted: 09/04/2020] [Indexed: 11/29/2022]
Abstract
We examined whether transcranial magnetic stimulation (TMS) delivered to the motor cortex allows assessment of muscle relaxation rates in unfatigued and fatigued knee extensors (KE). We assessed the ability of this technique to measure time course of fatigue-induced changes in muscle relaxation rate and compared relaxation rate from resting twitches evoked by femoral nerve stimulation. Twelve healthy men performed maximal voluntary isometric contractions (MVC) twice before (PRE) and once at the end of a 2-min KE MVC and five more times within 8 min during recovery. Relative (intraclass correlation coefficient; ICC2,1) and absolute (repeatability coefficient) reliability and variability (coefficient of variation) were assessed. Time course of fatigue-induced changes in muscle relaxation rate was tested with generalized estimating equations. In unfatigued KE, peak relaxation rate coefficient of variation and repeatability coefficient were similar for both techniques. Mean (95% CI) ICC2,1 for peak relaxation rates were 0.933 (0.724–0.982) and 0.889 (0.603–0.968) for TMS and femoral nerve stimulation, respectively. TMS-induced normalized muscle relaxation rate was − 11.5 ± 2.5 s−1 at PRE, decreased to − 6.9 ± 1.2 s−1 (− 37 ± 17%, P < 0.001), and recovered by 2 min post-exercise. Normalized peak relaxation rate for resting twitch did not show a fatigue-induced change. During fatiguing KE exercise, the change in muscle relaxation rate as determined by the two techniques was different. TMS provides reliable values of muscle relaxation rates. Furthermore, it is sufficiently sensitive and more appropriate than the resting twitch evoked by femoral nerve stimulation to reveal fatigue-induced changes in KE.
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Affiliation(s)
- Gianluca Vernillo
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Department of Biomedical Sciences for Health, Università Degli Studi di Milano, Milan, Italy
| | - Arash Khassetarash
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Guillaume Y Millet
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,University of Lyon, UJM Saint-Etienne, Inter-University Laboratory of Human Movement Biology, EA 7424), 42023, Saint-Etienne, France.,Institut Universitaire de France (IUF), Paris, France
| | - John Temesi
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada. .,Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK.
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27
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Regazzoni F, Dedè L, Quarteroni A. Biophysically detailed mathematical models of multiscale cardiac active mechanics. PLoS Comput Biol 2020; 16:e1008294. [PMID: 33027247 PMCID: PMC7571720 DOI: 10.1371/journal.pcbi.1008294] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 10/19/2020] [Accepted: 08/27/2020] [Indexed: 11/19/2022] Open
Abstract
We propose four novel mathematical models, describing the microscopic mechanisms of force generation in the cardiac muscle tissue, which are suitable for multiscale numerical simulations of cardiac electromechanics. Such models are based on a biophysically accurate representation of the regulatory and contractile proteins in the sarcomeres. Our models, unlike most of the sarcomere dynamics models that are available in the literature and that feature a comparable richness of detail, do not require the time-consuming Monte Carlo method for their numerical approximation. Conversely, the models that we propose only require the solution of a system of PDEs and/or ODEs (the most reduced of the four only involving 20 ODEs), thus entailing a significant computational efficiency. By focusing on the two models that feature the best trade-off between detail of description and identifiability of parameters, we propose a pipeline to calibrate such parameters starting from experimental measurements available in literature. Thanks to this pipeline, we calibrate these models for room-temperature rat and for body-temperature human cells. We show, by means of numerical simulations, that the proposed models correctly predict the main features of force generation, including the steady-state force-calcium and force-length relationships, the length-dependent prolongation of twitches and increase of peak force, the force-velocity relationship. Moreover, they correctly reproduce the Frank-Starling effect, when employed in multiscale 3D numerical simulation of cardiac electromechanics.
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Affiliation(s)
- Francesco Regazzoni
- MOX - Dipartimento di Matematica, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Luca Dedè
- MOX - Dipartimento di Matematica, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alfio Quarteroni
- MOX - Dipartimento di Matematica, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milano, Italy
- Mathematics Institute, École Polytechnique Fédérale de Lausanne, Av. Piccard, CH-1015 Lausanne, Switzerland (Professor Emeritus)
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28
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Pavadai E, Lehman W, Rynkiewicz MJ. Protein-Protein Docking Reveals Dynamic Interactions of Tropomyosin on Actin Filaments. Biophys J 2020; 119:75-86. [PMID: 32521240 DOI: 10.1016/j.bpj.2020.05.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/01/2020] [Accepted: 05/18/2020] [Indexed: 01/01/2023] Open
Abstract
Experimental approaches such as fiber diffraction and cryo-electron microscopy reconstruction have defined regulatory positions of tropomyosin on actin but have not, as yet, succeeded at determining key atomic-level contacts between these proteins or fully substantiated the dynamics of their interactions at a structural level. To overcome this deficiency, we have previously employed computational approaches to deduce global dynamics of thin filament components by energy landscape determination and molecular dynamics simulations. Still, these approaches remain computationally challenging for any complex and large macromolecular assembly like the thin filament. For example, tropomyosin cable wrapping around actin of thin filaments features both head-to-tail polymeric interactions and local twisting, both of which depart from strict superhelical symmetry. This produces a complex energy surface that is difficult to model and thus to evaluate globally. Therefore, at this stage of our understanding, assessing global molecular dynamics can prove to be inherently impractical. As an alternative, we adopted a "divide and conquer" protocol to investigate actin-tropomyosin interactions at an atomistic level. Here, we first employed unbiased protein-protein docking tools to identify binding specificity of individual tropomyosin pseudorepeat segments over the actin surface. Accordingly, tropomyosin "ligand" segments were rotated and translated over potential "target" binding sites on F-actin where the corresponding interaction energetics of billions of conformational poses were ranked by the programs PIPER and ClusPro. These data were used to assess favorable interactions and then to rebuild models of seamless and continuous tropomyosin cables over the F-actin substrate, which were optimized further by flexible fitting routines and molecular dynamics. The models generated azimuthally distinct regulatory positions for tropomyosin cables along thin filaments on actin dominated by stereo-specific head-to-tail overlap linkage. The outcomes are in good agreement with current cryo-electron microscopy topology and consistent with long-thought residue-to-residue interactions between actin and tropomyosin.
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Affiliation(s)
- Elumalai Pavadai
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, Massachusetts
| | - William Lehman
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, Massachusetts.
| | - Michael J Rynkiewicz
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, Massachusetts
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29
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de Winter JM, Molenaar JP, Yuen M, van der Pijl R, Shen S, Conijn S, van de Locht M, Willigenburg M, Bogaards SJ, van Kleef ES, Lassche S, Persson M, Rassier DE, Sztal TE, Ruparelia AA, Oorschot V, Ramm G, Hall TE, Xiong Z, Johnson CN, Li F, Kiss B, Lozano-Vidal N, Boon RA, Marabita M, Nogara L, Blaauw B, Rodenburg RJ, Küsters B, Doorduin J, Beggs AH, Granzier H, Campbell K, Ma W, Irving T, Malfatti E, Romero NB, Bryson-Richardson RJ, van Engelen BG, Voermans NC, Ottenheijm CA. KBTBD13 is an actin-binding protein that modulates muscle kinetics. J Clin Invest 2020; 130:754-767. [PMID: 31671076 PMCID: PMC6994151 DOI: 10.1172/jci124000] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/24/2019] [Indexed: 11/17/2022] Open
Abstract
The mechanisms that modulate the kinetics of muscle relaxation are critically important for muscle function. A prime example of the impact of impaired relaxation kinetics is nemaline myopathy caused by mutations in KBTBD13 (NEM6). In addition to weakness, NEM6 patients have slow muscle relaxation, compromising contractility and daily life activities. The role of KBTBD13 in muscle is unknown, and the pathomechanism underlying NEM6 is undetermined. A combination of transcranial magnetic stimulation-induced muscle relaxation, muscle fiber- and sarcomere-contractility assays, low-angle x-ray diffraction, and superresolution microscopy revealed that the impaired muscle-relaxation kinetics in NEM6 patients are caused by structural changes in the thin filament, a sarcomeric microstructure. Using homology modeling and binding and contractility assays with recombinant KBTBD13, Kbtbd13-knockout and Kbtbd13R408C-knockin mouse models, and a GFP-labeled Kbtbd13-transgenic zebrafish model, we discovered that KBTBD13 binds to actin - a major constituent of the thin filament - and that mutations in KBTBD13 cause structural changes impairing muscle-relaxation kinetics. We propose that this actin-based impaired relaxation is central to NEM6 pathology.
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Affiliation(s)
| | - Joery P. Molenaar
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
- Department of Neurology, Rijnstate Hospital, Arnhem, Netherlands
| | - Michaela Yuen
- Department of Physiology, Amsterdam University Medical Center, Netherlands
- Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Australia
| | - Robbert van der Pijl
- Department of Physiology, Amsterdam University Medical Center, Netherlands
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, USA
| | - Shengyi Shen
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, USA
| | - Stefan Conijn
- Department of Physiology, Amsterdam University Medical Center, Netherlands
| | | | - Menne Willigenburg
- Department of Physiology, Amsterdam University Medical Center, Netherlands
| | | | - Esmee S.B. van Kleef
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Saskia Lassche
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Malin Persson
- Department of Kinesiology and Physical Education, McGill University, Montreal, Canada
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Dilson E. Rassier
- Department of Kinesiology and Physical Education, McGill University, Montreal, Canada
| | - Tamar E. Sztal
- School of Biological Sciences, Monash University, Melbourne, Australia
| | | | - Viola Oorschot
- Monash Ramaciotti Centre for Structural Cryo-Electron Microscopy, Monash University, Melbourne, Australia
| | - Georg Ramm
- Monash Ramaciotti Centre for Structural Cryo-Electron Microscopy, Monash University, Melbourne, Australia
- Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Thomas E. Hall
- Institute for Molecular Bioscience, University of Queensland, Queensland, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, University of Queensland, Queensland, Australia
| | - Christopher N. Johnson
- Division of Clinical Pharmacology, Center for Arrhythmia Research and Therapeutics and Center for Structural Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Frank Li
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, USA
| | - Balazs Kiss
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, USA
| | | | - Reinier A. Boon
- Department of Physiology, Amsterdam University Medical Center, Netherlands
| | - Manuela Marabita
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Italy
| | - Leonardo Nogara
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Italy
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Italy
| | - Richard J. Rodenburg
- Department of Pediatrics, Radboud University Medical Centre, Translational Metabolic Laboratory, Nijmegen, Netherlands
| | - Benno Küsters
- Department of Pathology, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Jonne Doorduin
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alan H. Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, USA
| | - Ken Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Weikang Ma
- BioCAT, Illinois Institute of Technology, Chicago, Illinois, USA
| | - Thomas Irving
- BioCAT, Illinois Institute of Technology, Chicago, Illinois, USA
| | - Edoardo Malfatti
- Service Neurologie Médicale, Centre de Référence Maladies Neuromusculaire Paris-Nord CHU Raymond-Poincaré, U1179 UVSQ-INSERM Handicap Neuromusculaire: Physiologie, Biothérapie et Pharmacologie Appliquées, UFR des Sciences de la Santé Simone Veil, Université Versailles-Saint-Quentin-en-Yvelines, Garches, France
| | - Norma B. Romero
- Sorbonne Université, Myology Institute, Neuromuscular Morphology Unit, Center for Research in Myology, GH Pitié-Salpêtrière Paris, France
- Centre de Référence de Pathologie Neuromusculaire Paris-Est, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | | | - Baziel G.M. van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Nicol C. Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Coen A.C. Ottenheijm
- Department of Physiology, Amsterdam University Medical Center, Netherlands
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, USA
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30
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Lin YH, Schmidt W, Fritz KS, Jeong MY, Cammarato A, Foster DB, Biesiadecki BJ, McKinsey TA, Woulfe KC. Site-specific acetyl-mimetic modification of cardiac troponin I modulates myofilament relaxation and calcium sensitivity. J Mol Cell Cardiol 2020; 139:135-147. [PMID: 31981571 DOI: 10.1016/j.yjmcc.2020.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Cardiac troponin I (cTnI) is an essential physiological and pathological regulator of cardiac relaxation. Significant to this regulation, the post-translational modification of cTnI through phosphorylation functions as a key mechanism to accelerate myofibril relaxation. Similar to phosphorylation, post-translational modification by acetylation alters amino acid charge and protein function. Recent studies have demonstrated that the acetylation of cardiac myofibril proteins accelerates relaxation and that cTnI is acetylated in the heart. These findings highlight the potential significance of myofilament acetylation; however, it is not known if site-specific acetylation of cTnI can lead to changes in myofilament, myofibril, and/or cellular mechanics. The objective of this study was to determine the effects of mimicking acetylation at a single site of cTnI (lysine-132; K132) on myofilament, myofibril, and cellular mechanics and elucidate its influence on molecular function. METHODS To determine if pseudo-acetylation of cTnI at 132 modulates thin filament regulation of the acto-myosin interaction, we reconstituted thin filaments containing WT or K132Q (to mimic acetylation) cTnI and assessed in vitro motility. To test if mimicking acetylation at K132 alters cellular relaxation, adult rat ventricular cardiomyocytes were infected with adenoviral constructs expressing either cTnI K132Q or K132 replaced with arginine (K132R; to prevent acetylation) and cell shortening and isolated myofibril mechanics were measured. Finally, to confirm that changes in cell shortening and myofibril mechanics were directly due to pseudo-acetylation of cTnI at K132, we exchanged troponin containing WT or K132Q cTnI into isolated myofibrils and measured myofibril mechanical properties. RESULTS Reconstituted thin filaments containing K132Q cTnI exhibited decreased calcium sensitivity compared to thin filaments reconstituted with WT cTnI. Cardiomyocytes expressing K132Q cTnI had faster relengthening and myofibrils isolated from these cells had faster relaxation along with decreased calcium sensitivity compared to cardiomyocytes expressing WT or K132R cTnI. Myofibrils exchanged with K132Q cTnI ex vivo demonstrated faster relaxation and decreased calcium sensitivity. CONCLUSIONS Our results indicate for the first time that mimicking acetylation of a specific cTnI lysine accelerates myofilament, myofibril, and myocyte relaxation. This work underscores the importance of understanding how acetylation of specific sarcomeric proteins affects cardiac homeostasis and disease and suggests that modulation of myofilament lysine acetylation may represent a novel therapeutic target to alter cardiac relaxation.
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Affiliation(s)
- Ying H Lin
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - William Schmidt
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Kristofer S Fritz
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Mark Y Jeong
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Timothy A McKinsey
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America; Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
| | - Kathleen C Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
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31
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Persson M, Steinz MM, Westerblad H, Lanner JT, Rassier DE. Force generated by myosin cross-bridges is reduced in myofibrils exposed to ROS/RNS. Am J Physiol Cell Physiol 2019; 317:C1304-C1312. [DOI: 10.1152/ajpcell.00272.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Skeletal muscle weakness is associated with oxidative stress and oxidative posttranslational modifications on contractile proteins. There is indirect evidence that reactive oxygen/nitrogen species (ROS/RNS) affect skeletal muscle myofibrillar function, although the details of the acute effects of ROS/RNS on myosin-actin interactions are not known. In this study, we examined the effects of peroxynitrite (ONOO−) on the contractile properties of individual skeletal muscle myofibrils by monitoring myofibril-induced displacements of an atomic force cantilever upon activation and relaxation. The isometric force decreased by ~50% in myofibrils treated with the ONOO− donor (SIN-1) or directly with ONOO−, which was independent of the cross-bridge abundancy condition (i.e., rigor or relaxing condition) during SIN-1 or ONOO− treatment. The force decrease was attributed to an increase in the cross-bridge detachment rate ( gapp) in combination with a conservation of the force redevelopment rate (kTr) and hence, an increase in the population of cross-bridges transitioning from force-generating to non-force-generating cross-bridges during steady-state. Taken together, the results of this study provide important information on how ROS/RNS affect myofibrillar force production which may be of importance for conditions where increased oxidative stress is part of the pathophysiology.
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Affiliation(s)
- Malin Persson
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Maarten M. Steinz
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Håkan Westerblad
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Johanna T. Lanner
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Dilson E. Rassier
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
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32
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The relation between sarcomere energetics and the rate of isometric tension relaxation in healthy and diseased cardiac muscle. J Muscle Res Cell Motil 2019; 42:47-57. [PMID: 31745760 PMCID: PMC7932984 DOI: 10.1007/s10974-019-09566-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/13/2019] [Indexed: 12/24/2022]
Abstract
Full muscle relaxation happens when [Ca2+] falls below the threshold for force activation. Several experimental models, from whole muscle organs and intact muscle down to skinned fibers, have been used to explore the cascade of kinetic events leading to mechanical relaxation. The use of single myofibrils together with fast solution switching techniques, has provided new information about the role of cross-bridge (CB) dissociation in the time course of isometric force decay. Myofibril’s relaxation is biphasic starting with a slow seemingly linear phase, with a rate constant, slow kREL, followed by a fast mono-exponential phase. Sarcomeres remain isometric during the slow force decay that reflects CB detachment under isometric conditions while the final fast relaxation phase begins with a sudden give of few sarcomeres and is then dominated by intersarcomere dynamics. Based on a simple two-state model of the CB cycle, myofibril slow kREL represents the apparent forward rate with which CBs leave force generating states (gapp) under isometric conditions and correlates with the energy cost of tension generation (ATPase/tension ratio); in short slow kREL ~ gapp ~ tension cost. The validation of this relationship is obtained by simultaneously measuring maximal isometric force and ATP consumption in skinned myocardial strips that provide an unambiguous determination of the relation between contractile and energetic properties of the sarcomere. Thus, combining kinetic experiments in isolated myofibrils and mechanical and energetic measurements in multicellular cardiac strips, we are able to provide direct evidence for a positive linear correlation between myofibril isometric relaxation kinetics (slow kREL) and the energy cost of force production both measured in preparations from the same cardiac sample. This correlation remains true among different types of muscles with different ATPase activities and also when CB kinetics are altered by cardiomyopathy-related mutations. Sarcomeric mutations associated to hypertrophic cardiomyopathy (HCM), a primary cardiac disorder caused by mutations in genes encoding sarcomeric proteins, have been often found to accelerate CB turnover rate and increase the energy cost of myocardial contraction. Here we review data showing that faster CB detachment results in a proportional increase in the energetic cost of tension generation in heart samples from both HCM patients and mouse models of the disease.
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33
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Månsson A. The effects of inorganic phosphate on muscle force development and energetics: challenges in modelling related to experimental uncertainties. J Muscle Res Cell Motil 2019; 42:33-46. [PMID: 31620962 PMCID: PMC7932973 DOI: 10.1007/s10974-019-09558-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 10/09/2019] [Indexed: 02/03/2023]
Abstract
Muscle force and power are developed by myosin cross-bridges, which cyclically attach to actin, undergo a force-generating transition and detach under turnover of ATP. The force-generating transition is intimately associated with release of inorganic phosphate (Pi) but the exact sequence of events in relation to the actual Pi release step is controversial. Details of this process are reflected in the relationships between [Pi] and the developed force and shortening velocity. In order to account for these relationships, models have proposed branched kinetic pathways or loose coupling between biochemical and force-generating transitions. A key hypothesis underlying the present study is that such complexities are not required to explain changes in the force–velocity relationship and ATP turnover rate with altered [Pi]. We therefore set out to test if models without branched kinetic paths and Pi-release occurring before the main force-generating transition can account for effects of varied [Pi] (0.1–25 mM). The models tested, one assuming either linear or non-linear cross-bridge elasticity, account well for critical aspects of muscle contraction at 0.5 mM Pi but their capacity to account for the maximum power output vary. We find that the models, within experimental uncertainties, account for the relationship between [Pi] and isometric force as well as between [Pi] and the velocity of shortening at low loads. However, in apparent contradiction with available experimental findings, the tested models produce an anomalous force–velocity relationship at elevated [Pi] and high loads with more than one possible velocity for a given load. Nevertheless, considering experimental uncertainties and effects of sarcomere non-uniformities, these discrepancies are insufficient to refute the tested models in favour of more complex alternatives.
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Affiliation(s)
- Alf Månsson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, Universitetskajen, 391 82, Kalmar, Sweden.
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34
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Geeves MA, Lehrer SS, Lehman W. The mechanism of thin filament regulation: Models in conflict? J Gen Physiol 2019; 151:1265-1271. [PMID: 31570503 PMCID: PMC6829557 DOI: 10.1085/jgp.201912446] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 09/05/2019] [Indexed: 01/29/2023] Open
Abstract
Evidence on two- and three-state models of the calcium regulation models of muscle contractions remain in favor of three-state models. In a recent JGP article, Heeley et al. (2019. J. Gen. Physiol. https://doi.org/10.1085/jgp.201812198) reopened the debate about two- versus three-state models of thin filament regulation. The authors review their work, which measures the rate constant of Pi release from myosin.ADP.Pi activated by actin or thin filaments under a variety of conditions. They conclude that their data can be described by a two-state model and raise doubts about the generally accepted three-state model as originally formulated by McKillop and Geeves (1993. Biophys. J.https://doi.org/10.1016/S0006-3495(93)81110-X). However, in the following article, we follow Plato’s dictum that “twice and thrice over, as they say, good it is to repeat and review what is good.” We have therefore reviewed the evidence for the three- and two-state models and present our view that the evidence is overwhelmingly in favor of three structural states of the thin filament, which regulate access of myosin to its binding sites on actin and, hence, muscle contractility.
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Affiliation(s)
| | | | - William Lehman
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA
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35
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Jeong MY, Lin YH, Wennersten SA, Demos-Davies KM, Cavasin MA, Mahaffey JH, Monzani V, Saripalli C, Mascagni P, Reece TB, Ambardekar AV, Granzier HL, Dinarello CA, McKinsey TA. Histone deacetylase activity governs diastolic dysfunction through a nongenomic mechanism. Sci Transl Med 2019; 10:10/427/eaao0144. [PMID: 29437146 DOI: 10.1126/scitranslmed.aao0144] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/07/2017] [Accepted: 01/05/2018] [Indexed: 12/21/2022]
Abstract
There are no approved drugs for the treatment of heart failure with preserved ejection fraction (HFpEF), which is characterized by left ventricular (LV) diastolic dysfunction. We demonstrate that ITF2357 (givinostat), a clinical-stage inhibitor of histone deacetylase (HDAC) catalytic activity, is efficacious in two distinct murine models of diastolic dysfunction with preserved EF. ITF2357 blocked LV diastolic dysfunction due to hypertension in Dahl salt-sensitive (DSS) rats and suppressed aging-induced diastolic dysfunction in normotensive mice. HDAC inhibitor-mediated efficacy was not due to lowering blood pressure or inhibiting cellular and molecular events commonly associated with diastolic dysfunction, including cardiac fibrosis, cardiac hypertrophy, or changes in cardiac titin and myosin isoform expression. Instead, ex vivo studies revealed impairment of cardiac myofibril relaxation as a previously unrecognized, myocyte-autonomous mechanism for diastolic dysfunction, which can be ameliorated by HDAC inhibition. Translating these findings to humans, cardiac myofibrils from patients with diastolic dysfunction and preserved EF also exhibited compromised relaxation. These data suggest that agents such as HDAC inhibitors, which potentiate cardiac myofibril relaxation, hold promise for the treatment of HFpEF in humans.
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Affiliation(s)
- Mark Y Jeong
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ying H Lin
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sara A Wennersten
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kimberly M Demos-Davies
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Maria A Cavasin
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jennifer H Mahaffey
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Chandrasekhar Saripalli
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85724, USA
| | | | - T Brett Reece
- Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Amrut V Ambardekar
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85724, USA
| | - Charles A Dinarello
- Division of Infectious Diseases, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Timothy A McKinsey
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA. .,Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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36
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Piroddi N, Witjas-Paalberends ER, Ferrara C, Ferrantini C, Vitale G, Scellini B, Wijnker PJM, Sequiera V, Dooijes D, Dos Remedios C, Schlossarek S, Leung MC, Messer A, Ward DG, Biggeri A, Tesi C, Carrier L, Redwood CS, Marston SB, van der Velden J, Poggesi C. The homozygous K280N troponin T mutation alters cross-bridge kinetics and energetics in human HCM. J Gen Physiol 2018; 151:18-29. [PMID: 30578328 PMCID: PMC6314385 DOI: 10.1085/jgp.201812160] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/29/2018] [Indexed: 01/24/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is caused by mutations in sarcomeric proteins, but the pathogenic mechanism is unclear. Piroddi et al. find impairment of cross-bridge kinetics and energetics in human sarcomeres with a TNNT2 mutation, suggesting that HCM involves inefficient ATP utilization. Hypertrophic cardiomyopathy (HCM) is a genetic form of left ventricular hypertrophy, primarily caused by mutations in sarcomere proteins. The cardiac remodeling that occurs as the disease develops can mask the pathogenic impact of the mutation. Here, to discriminate between mutation-induced and disease-related changes in myofilament function, we investigate the pathogenic mechanisms underlying HCM in a patient carrying a homozygous mutation (K280N) in the cardiac troponin T gene (TNNT2), which results in 100% mutant cardiac troponin T. We examine sarcomere mechanics and energetics in K280N-isolated myofibrils and demembranated muscle strips, before and after replacement of the endogenous troponin. We also compare these data to those of control preparations from donor hearts, aortic stenosis patients (LVHao), and HCM patients negative for sarcomeric protein mutations (HCMsmn). The rate constant of tension generation following maximal Ca2+ activation (kACT) and the rate constant of isometric relaxation (slow kREL) are markedly faster in K280N myofibrils than in all control groups. Simultaneous measurements of maximal isometric ATPase activity and Ca2+-activated tension in demembranated muscle strips also demonstrate that the energy cost of tension generation is higher in the K280N than in all controls. Replacement of mutant protein by exchange with wild-type troponin in the K280N preparations reduces kACT, slow kREL, and tension cost close to control values. In donor myofibrils and HCMsmn demembranated strips, replacement of endogenous troponin with troponin containing the K280N mutant increases kACT, slow kREL, and tension cost. The K280N TNNT2 mutation directly alters the apparent cross-bridge kinetics and impairs sarcomere energetics. This result supports the hypothesis that inefficient ATP utilization by myofilaments plays a central role in the pathogenesis of the disease.
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Affiliation(s)
- Nicoletta Piroddi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - E Rosalie Witjas-Paalberends
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Claudia Ferrara
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Cecilia Ferrantini
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy.,LENS, Sesto Fiorentino (Firenze), Florence, Italy
| | - Giulia Vitale
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Beatrice Scellini
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Paul J M Wijnker
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Vasco Sequiera
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Dennis Dooijes
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Clinical Genetics, University Medical Center, Utrecht, Netherlands
| | - Cristobal Dos Remedios
- Department of Anatomy and Histology, Bosch Institute, The University of Sydney, Sydney, Australia
| | - Saskia Schlossarek
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Man Ching Leung
- National Heart and Lung Institute, Imperial College, London, England, UK
| | - Andrew Messer
- National Heart and Lung Institute, Imperial College, London, England, UK
| | - Douglas G Ward
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | | | - Chiara Tesi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | | | - Steven B Marston
- National Heart and Lung Institute, Imperial College, London, England, UK
| | - Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Clinical Genetics, University Medical Center, Utrecht, Netherlands.,ICIN-Netherlands, Heart Institute, Utrecht, Netherlands
| | - Corrado Poggesi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy .,LENS, Sesto Fiorentino (Firenze), Florence, Italy
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37
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Dvornikov AV, de Tombe PP, Xu X. Phenotyping cardiomyopathy in adult zebrafish. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:116-125. [PMID: 29884423 PMCID: PMC6269218 DOI: 10.1016/j.pbiomolbio.2018.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/26/2018] [Accepted: 05/29/2018] [Indexed: 12/21/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is usually manifested by increased myofilament Ca2+ sensitivity, excessive contractility, and impaired relaxation. In contrast, dilated cardiomyopathy (DCM) originates from insufficient sarcomere contractility and reduced cardiac pump function, subsequently resulting in heart failure. The zebrafish has emerged as a new model of human cardiomyopathy with high-throughput screening, which will facilitate the discovery of novel genetic factors and the development of new therapies. Given the small hearts of zebrafish, better phenotyping tools are needed to discern different types of cardiomyopathy, such as HCM and DCM. This article reviews the existing models of cardiomyopathy, available morphologic and functional methods, and current understanding of the different types of cardiomyopathy in adult zebrafish.
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Affiliation(s)
- Alexey V Dvornikov
- Department of Biochemistry and Molecular Biology, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.
| | - Pieter P de Tombe
- University of Illinois at Chicago, Department of Physiology and Biophysics, Chicago, IL, USA; Magdi Yacoub Institute, Cardiac Biophysics Division, Harefield, UK; Imperial College, Heart and Lung Institute, London, UK; Freiburg University, Institute for Experimental Cardiovascular Medicine, Germany
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.
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38
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Vikhorev PG, Vikhoreva NN. Cardiomyopathies and Related Changes in Contractility of Human Heart Muscle. Int J Mol Sci 2018; 19:ijms19082234. [PMID: 30065175 PMCID: PMC6121228 DOI: 10.3390/ijms19082234] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/22/2018] [Accepted: 07/27/2018] [Indexed: 02/07/2023] Open
Abstract
About half of hypertrophic and dilated cardiomyopathies cases have been recognized as genetic diseases with mutations in sarcomeric proteins. The sarcomeric proteins are involved in cardiomyocyte contractility and its regulation, and play a structural role. Mutations in non-sarcomeric proteins may induce changes in cell signaling pathways that modify contractile response of heart muscle. These facts strongly suggest that contractile dysfunction plays a central role in initiation and progression of cardiomyopathies. In fact, abnormalities in contractile mechanics of myofibrils have been discovered. However, it has not been revealed how these mutations increase risk for cardiomyopathy and cause the disease. Much research has been done and still much is being done to understand how the mechanism works. Here, we review the facts of cardiac myofilament contractility in patients with cardiomyopathy and heart failure.
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Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Natalia N Vikhoreva
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK.
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39
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Nogueira L, Trisko BM, Lima‐Rosa FL, Jackson J, Lund‐Palau H, Yamaguchi M, Breen EC. Cigarette smoke directly impairs skeletal muscle function through capillary regression and altered myofibre calcium kinetics in mice. J Physiol 2018; 596:2901-2916. [PMID: 29797443 PMCID: PMC6046067 DOI: 10.1113/jp275888] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/18/2018] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Cigarette smoke components directly alter muscle fatigue resistance and intracellular muscle fibre Ca2+ handling independent of a change in lung structure. Changes in muscle vascular structure are associated with a depletion of satellite cells. Sarcoplasmic reticulum Ca2+ uptake is substantially impaired in myofibres during fatiguing contractions in mice treated with cigarette smoke extract. ABSTRACT Cigarette smokers exhibit exercise intolerance before a decline in respiratory function. In the present study, the direct effects of cigarette smoke on limb muscle function were tested by comparing cigarette smoke delivered to mice by weekly injections of cigarette smoke extract (CSE), or nose-only exposure (CS) 5 days each week, for 8 weeks. Cigarette smoke delivered by either route did not alter pulmonary airspace size. Muscle fatigue measured in situ was 50% lower in the CSE and CS groups than in control. This was accompanied by 34% and 22% decreases in soleus capillary-to-fibre ratio of the CSE and CS groups, respectively, and a trend for fewer skeletal muscle actin-positive arterioles (P = 0.07). In addition, fewer quiescent satellite cells (Nes+Pax7+) were associated with soleus fibres in mice with skeletal myofibre VEGF gene deletion (decreased 47%) and CS exposed (decreased 73%) than with control fibres. Contractile properties of isolated extensor digitorum longus and soleus muscles were impaired. In flexor digitorum brevis myofibres isolated from CSE mice, fatigue resistance was diminished by 43% compared to control and CS myofibres, and this was accompanied by a pronounced slowing in relaxation, an increase in intracellular Ca2+ accumulation, and a slowing in sarcoplasmic reticulum Ca2+ uptake. These data suggest that cigarette smoke components may impair hindlimb muscle vascular structure, fatigue resistance and myofibre calcium handling, and these changes ultimately affect contractile efficiency of locomotor muscles independent of a change in lung function.
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Affiliation(s)
- Leonardo Nogueira
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM‐LDM)Universidade Federal do Rio de JaneiroRio de JaneiroRJBrazil
| | - Breanna M. Trisko
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Frederico L. Lima‐Rosa
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM‐LDM)Universidade Federal do Rio de JaneiroRio de JaneiroRJBrazil
| | - Jason Jackson
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Helena Lund‐Palau
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Masahiro Yamaguchi
- Department of Physiology, Kochi Medical SchoolKochi UniversityKochiJapan
| | - Ellen C. Breen
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
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Iorga B, Schwanke K, Weber N, Wendland M, Greten S, Piep B, Dos Remedios CG, Martin U, Zweigerdt R, Kraft T, Brenner B. Differences in Contractile Function of Myofibrils within Human Embryonic Stem Cell-Derived Cardiomyocytes vs. Adult Ventricular Myofibrils Are Related to Distinct Sarcomeric Protein Isoforms. Front Physiol 2018; 8:1111. [PMID: 29403388 PMCID: PMC5780405 DOI: 10.3389/fphys.2017.01111] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 12/15/2017] [Indexed: 01/10/2023] Open
Abstract
Characterizing the contractile function of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is key for advancing their utility for cellular disease models, promoting cell based heart repair, or developing novel pharmacological interventions targeting cardiac diseases. The aim of the present study was to understand whether steady-state and kinetic force parameters of β-myosin heavy chain (βMyHC) isoform-expressing myofibrils within human embryonic stem cell-derived cardiomyocytes (hESC-CMs) differentiated in vitro resemble those of human ventricular myofibrils (hvMFs) isolated from adult donor hearts. Contractile parameters were determined using the same micromechanical method and experimental conditions for both types of myofibrils. We identified isoforms and phosphorylation of main sarcomeric proteins involved in the modulation of force generation of both, chemically demembranated hESC-CMs (d-hESC-CMs) and hvMFs. Our results indicate that at saturating Ca2+ concentration, both human-derived contractile systems developed forces with similar rate constants (0.66 and 0.68 s−1), reaching maximum isometric force that was significantly smaller for d-hESC-CMs (42 kPa) than for hvMFs (94 kPa). At submaximal Ca2+-activation, where intact cardiomyocytes normally operate, contractile parameters of d-hESC-CMs and hvMFs exhibited differences. Ca2+ sensitivity of force was higher for d-hESC-CMs (pCa50 = 6.04) than for hvMFs (pCa50 = 5.80). At half-maximum activation, the rate constant for force redevelopment was significantly faster for d-hESC-CMs (0.51 s−1) than for hvMFs (0.28 s−1). During myofibril relaxation, kinetics of the slow force decay phase were significantly faster for d-hESC-CMs (0.26 s−1) than for hvMFs (0.21 s−1), while kinetics of the fast force decay were similar and ~20x faster. Protein analysis revealed that hESC-CMs had essentially no cardiac troponin-I, and partially non-ventricular isoforms of some other sarcomeric proteins, explaining the functional discrepancies. The sarcomeric protein isoform pattern of hESC-CMs had features of human cardiomyocytes at an early developmental stage. The study indicates that morphological and ultrastructural maturation of βMyHC isoform-expressing hESC-CMs is not necessarily accompanied by ventricular-like expression of all sarcomeric proteins. Our data suggest that hPSC-CMs could provide useful tools for investigating inherited cardiac diseases affecting contractile function during early developmental stages.
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Affiliation(s)
- Bogdan Iorga
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany.,Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Kristin Schwanke
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs, REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Hannover, Germany
| | - Natalie Weber
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Meike Wendland
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Stephan Greten
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Birgit Piep
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | | | - Ulrich Martin
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs, REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Hannover, Germany
| | - Robert Zweigerdt
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs, REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Hannover, Germany
| | - Theresia Kraft
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Bernhard Brenner
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
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41
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Irving M. Regulation of Contraction by the Thick Filaments in Skeletal Muscle. Biophys J 2017; 113:2579-2594. [PMID: 29262355 PMCID: PMC5770512 DOI: 10.1016/j.bpj.2017.09.037] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/27/2017] [Accepted: 09/29/2017] [Indexed: 11/23/2022] Open
Abstract
Contraction of skeletal muscle cells is initiated by a well-known signaling pathway. An action potential in a motor nerve triggers an action potential in a muscle cell membrane, a transient increase of intracellular calcium concentration, binding of calcium to troponin in the actin-containing thin filaments, and a structural change in the thin filaments that allows myosin motors from the thick filaments to bind to actin and generate force. This calcium/thin filament mediated pathway provides the "START" signal for contraction, but it is argued that the functional response of the muscle cell, including the speed of its contraction and relaxation, adaptation to the external load, and the metabolic cost of contraction is largely determined by additional mechanisms. This review considers the role of the thick filaments in those mechanisms, and puts forward a paradigm for the control of contraction in skeletal muscle in which both the thick and thin filaments have a regulatory function. The OFF state of the thick filament is characterized by helical packing of most of the myosin head or motor domains on the thick filament surface in a conformation that makes them unavailable for actin binding or ATP hydrolysis, although a small fraction of the myosin heads are constitutively ON. The availability of the majority fraction of the myosin heads for contraction is controlled in part by the external load on the muscle, so that these heads only attach to actin and hydrolyze ATP when they are required. This phenomenon seems to be the major determinant of the well-known force-velocity relationship of muscle, and controls the metabolic cost of contraction. The regulatory state of the thick filament also seems to control the dynamics of both muscle activation and relaxation.
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Affiliation(s)
- Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics and BHF Centre of Research Excellence, King's College London, London, United Kingdom.
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42
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Kinetic coupling of phosphate release, force generation and rate-limiting steps in the cross-bridge cycle. J Muscle Res Cell Motil 2017; 38:275-289. [PMID: 28918606 DOI: 10.1007/s10974-017-9482-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/12/2017] [Indexed: 10/18/2022]
Abstract
A basic goal in muscle research is to understand how the cyclic ATPase activity of cross-bridges is converted into mechanical force. A direct approach to study the chemo-mechanical coupling between Pi release and the force-generating step is provided by the kinetics of force response induced by a rapid change in [Pi]. Classical studies on fibres using caged-Pi discovered that rapid increases in [Pi] induce fast force decays dependent on final [Pi] whose kinetics were interpreted to probe a fast force-generating step prior to Pi release. However, this hypothesis was called into question by studies on skeletal and cardiac myofibrils subjected to Pi jumps in both directions (increases and decreases in [Pi]) which revealed that rapid decreases in [Pi] trigger force rises with slow kinetics, similar to those of calcium-induced force development and mechanically-induced force redevelopment at the same [Pi]. A possible explanation for this discrepancy came from imaging of individual sarcomeres in cardiac myofibrils, showing that the fast force decay upon increase in [Pi] results from so-called sarcomere 'give'. The slow force rise upon decrease in [Pi] was found to better reflect overall sarcomeres cross-bridge kinetics and its [Pi] dependence, suggesting that the force generation coupled to Pi release cannot be separated from the rate-limiting transition. The reasons for the different conclusions achieved in fibre and myofibril studies are re-examined as the recent findings on cardiac myofibrils have fundamental consequences for the coupling between Pi release, rate-limiting steps and force generation. The implications from Pi-induced force kinetics of myofibrils are discussed in combination with historical and recent models of the cross-bridge cycle.
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43
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Regnier M, Cheng Y. Finally, We Can Relax: A New Generation of Muscle Models that Incorporate Sarcomere Compliance. Biophys J 2017; 110:521-522. [PMID: 26840717 DOI: 10.1016/j.bpj.2015.12.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 12/21/2015] [Indexed: 10/22/2022] Open
Affiliation(s)
- Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington; Center for Cardiovascular Biology, University of Washington, Seattle, Washington; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington.
| | - Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington
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44
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Stehle R. Force Responses and Sarcomere Dynamics of Cardiac Myofibrils Induced by Rapid Changes in [P i]. Biophys J 2017; 112:356-367. [PMID: 28122221 DOI: 10.1016/j.bpj.2016.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 11/02/2016] [Accepted: 11/04/2016] [Indexed: 11/16/2022] Open
Abstract
The second phase of the biphasic force decay upon release of phosphate from caged phosphate was previously interpreted as a signature of kinetics of the force-generating step in the cross-bridge cycle. To test this hypothesis without using caged compounds, force responses and individual sarcomere dynamics upon rapid increases or decreases in concentration of inorganic phosphate [Pi] were investigated in calcium-activated cardiac myofibrils. Rapid increases in [Pi] induced a biphasic force decay with an initial slow decline (phase 1) and a subsequent 3-5-fold faster major decay (phase 2). Phase 2 started with the distinct elongation of a single sarcomere, the so-called sarcomere "give". "Give" then propagated from sarcomere to sarcomere along the myofibril. Propagation speed and rate constant of phase 2 (k+Pi(2)) had a similar [Pi]-dependence, indicating that the kinetics of the major force decay (phase 2) upon rapid increase in [Pi] is determined by sarcomere dynamics. In contrast, no "give" was observed during phase 1 after rapid [Pi]-increase (rate constant k+Pi(1)) and during the single-exponential force rise (rate constant k-Pi) after rapid [Pi]-decrease. The values of k+Pi(1) and k-Pi were similar to the rate constant of mechanically induced force redevelopment (kTR) and Ca2+-induced force development (kACT) measured at same [Pi]. These results indicate that the major phase 2 of force decay upon a Pi-jump does not reflect kinetics of the force-generating step but results from sarcomere "give". The other phases of Pi-induced force kinetics that occur in the absence of "give" yield the same information as mechanically and Ca2+-induced force kinetics (k+Pi(1) ∼ k-Pi ∼ kTR ∼ kACT). Model simulations indicate that Pi-induced force kinetics neither enable the separation of Pi-release from the rate-limiting transition f into force states nor differentiate whether the "force-generating step" occurs before, along, or after the Pi-release.
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Affiliation(s)
- Robert Stehle
- Institute of Vegetative Physiology, University of Cologne, Köln, Germany.
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45
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The Relaxation Properties of Myofibrils Are Compromised by Amino Acids that Stabilize α-Tropomyosin. Biophys J 2017; 112:376-387. [PMID: 28122223 DOI: 10.1016/j.bpj.2016.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 12/20/2022] Open
Abstract
We investigated the functional impact of α-tropomyosin (Tm) substituted with one (D137L) or two (D137L/G126R) stabilizing amino acid substitutions on the mechanical behavior of rabbit psoas skeletal myofibrils by replacing endogenous Tm and troponin (Tn) with recombinant Tm mutants and purified skeletal Tn. Force recordings from myofibrils (15°C) at saturating [Ca2+] showed that Tm-stabilizing substitutions did not significantly affect the maximal isometric tension and the rates of force activation (kACT) and redevelopment (kTR). However, a clear effect was observed on force relaxation: myofibrils with D137L/G126R or D137L Tm showed prolonged durations of the slow phase of relaxation and decreased rates of the fast phase. Both Tm-stabilizing substitutions strongly decreased the slack sarcomere length (SL) at submaximal activating [Ca2+] and increased the steepness of the SL-passive tension relation. These effects were reversed by addition of 10 mM 2,3-butanedione 2-monoxime. Myofibrils also showed an apparent increase in Ca2+ sensitivity. Measurements of myofibrillar ATPase activity in the absence of Ca2+ showed a significant increase in the presence of these Tms, indicating that single and double stabilizing substitutions compromise the full inhibition of contraction in the relaxed state. These data can be understood with the three-state (blocked-closed-open) theory of muscle regulation, according to which the mutations increase the contribution of the active open state in the absence of Ca2+ (M-). Force measurements on myofibrils substituted with C-terminal truncated TnI showed similar compromised relaxation effects, indicating the importance of TnI-Tm interactions in maintaining the blocked state. It appears that reducing the flexibility of native Tm coiled-coil structure decreases the optimum interactions of the central part of Tm with the C-terminal region of TnI. This results in a shift away from the blocked state, allowing myosin binding and activity in the absence of Ca2+. This work provides a basis for understanding the effects of disease-producing mutations in muscle proteins.
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46
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Demangel R, Treffel L, Py G, Brioche T, Pagano AF, Bareille MP, Beck A, Pessemesse L, Candau R, Gharib C, Chopard A, Millet C. Early structural and functional signature of 3-day human skeletal muscle disuse using the dry immersion model. J Physiol 2017; 595:4301-4315. [PMID: 28326563 DOI: 10.1113/jp273895] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/16/2017] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Our study contributes to the characterization of muscle loss and weakness processes induced by a sedentary life style, chronic hypoactivity, clinical bed rest, immobilization and microgravity. This study, by bringing together integrated and cellular evaluation of muscle structure and function, identifies the early functional markers and biomarkers of muscle deconditioning. Three days of muscle disuse in healthy adult subjects is sufficient to significantly decrease muscle mass, tone and force, and to induce changes in function relating to a weakness in aerobic metabolism and muscle fibre denervation. The outcomes of this study should be considered in the development of an early muscle loss prevention programme and/or the development of pre-conditioning programmes required before clinical bed rest, immobilization and spaceflight travel. ABSTRACT Microgravity and hypoactivity are associated with skeletal muscle deconditioning. The decrease of muscle mass follows an exponential decay, with major changes in the first days. The purpose of the study was to dissect out the effects of a short-term 3-day dry immersion (DI) on human quadriceps muscle function and structure. The DI model, by suppressing all support zones, accurately reproduces the effects of microgravity. Twelve healthy volunteers (32 ± 5 years) completed 3 days of DI. Muscle function was investigated through maximal voluntary contraction (MVC) tests and muscle viscoelasticity. Structural experiments were performed using MRI analysis and invasive experiments on muscle fibres. Our results indicated a significant 9.1% decrease of the normalized MVC constant (P = 0.048). Contraction and relaxation modelization kinetics reported modifications related to torque generation (kACT = -29%; P = 0.014) and to the relaxation phase (kREL = +34%; P = 0.040) after 3 days of DI. Muscle viscoelasticity was also altered. From day one, rectus femoris stiffness and tone decreased by, respectively, 7.3% (P = 0.002) and 10.2% (P = 0.002), and rectus femoris elasticity decreased by 31.5% (P = 0.004) after 3 days of DI. At the cellular level, 3 days of DI translated into a significant atrophy of type I muscle fibres (-10.6 ± 12.1%, P = 0.027) and an increased proportion of hybrid, type I/IIX fibre co-expression. Finally, we report an increase (6-fold; P = 0.002) in NCAM+ muscle fibres, showing an early denervation process. This study is the first to report experiments performed in Europe investigating human short-term DI-induced muscle adaptations, and contributes to deciphering the early changes and biomarkers of skeletal muscle deconditioning.
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Affiliation(s)
- Rémi Demangel
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Loïc Treffel
- Université Claude Bernard Lyon 1, Lyon, France.,Université de Strasbourg, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7178, Strasbourg, France
| | - Guillaume Py
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Thomas Brioche
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Allan F Pagano
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | | | - Arnaud Beck
- Institute for Space Medicine and Physiology (MEDES), Toulouse, France
| | - Laurence Pessemesse
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Robin Candau
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | | | - Angèle Chopard
- Université de Montpellier, INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Catherine Millet
- Université Claude Bernard Lyon 1, Lyon, France.,Service d'Odontologie, Hospices Civils de Lyon, Lyon, France
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47
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Chung CS, Hoopes CW, Campbell KS. Myocardial relaxation is accelerated by fast stretch, not reduced afterload. J Mol Cell Cardiol 2017; 103:65-73. [PMID: 28087265 DOI: 10.1016/j.yjmcc.2017.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/08/2017] [Accepted: 01/09/2017] [Indexed: 12/19/2022]
Abstract
Fast relaxation of cross-bridge generated force in the myocardium facilitates efficient diastolic function. Recently published research studying mechanisms that modulate the relaxation rate has focused on molecular factors. Mechanical factors have received less attention since the 1980s when seminal work established the theory that reducing afterload accelerates the relaxation rate. Clinical trials using afterload reducing drugs, partially based on this theory, have thus far failed to improve outcomes for patients with diastolic dysfunction. Therefore, we reevaluated the protocols that suggest reducing afterload accelerates the relaxation rate and identified that myocardial relengthening was a potential confounding factor. We hypothesized that the speed of myocardial relengthening at end systole (end systolic strain rate), and not afterload, modulates relaxation rate and tested this hypothesis using electrically-stimulated trabeculae from mice, rats, and humans. We used load-clamp techniques to vary afterload and end systolic strain rate independently. Our data show that the rate of relaxation increases monotonically with end systolic strain rate but is not altered by afterload. Computer simulations mimic this behavior and suggest that fast relengthening quickens relaxation by accelerating the detachment of cross-bridges. The relationship between relaxation rate and strain rate is novel and upends the prevailing theory that afterload modifies relaxation. In conclusion, myocardial relaxation is mechanically modified by the rate of stretch at end systole. The rate of myocardial relengthening at end systole may be a new diagnostic indicator or target for treatment of diastolic dysfunction.
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Affiliation(s)
- Charles S Chung
- Department of Physiology, Wayne State University, Detroit, MI, USA; Department of Physiology, University of Kentucky, Lexington, KY, USA.
| | - Charles W Hoopes
- Department of Surgery, University of Kentucky, Lexington, KY, USA
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY, USA; Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, USA
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48
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Weber N, Schwanke K, Greten S, Wendland M, Iorga B, Fischer M, Geers-Knörr C, Hegermann J, Wrede C, Fiedler J, Kempf H, Franke A, Piep B, Pfanne A, Thum T, Martin U, Brenner B, Zweigerdt R, Kraft T. Stiff matrix induces switch to pure β-cardiac myosin heavy chain expression in human ESC-derived cardiomyocytes. Basic Res Cardiol 2016; 111:68. [PMID: 27743117 DOI: 10.1007/s00395-016-0587-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 10/06/2016] [Indexed: 10/20/2022]
Abstract
Human pluripotent stem cell (hPSC)-derived cardiomyocytes hold great potential for in vitro modeling of diseases like cardiomyopathies. Yet, knowledge about expression and functional impact of sarcomeric protein isoforms like the myosin heavy chain (MyHC) in hPSC-cardiomyocytes is scarce. We hypothesized that ventricular β-MyHC expression alters contraction and calcium kinetics and drives morphological and electrophysiological differentiation towards ventricular-like cardiomyocytes. To address this, we (1) generated human embryonic stem cell-derived cardiomyocytes (hESC-CMs) that switched towards exclusive β-MyHC, and (2) functionally and morphologically characterized these hESC-CMs at the single-cell level. MyHC-isoforms and functional properties were investigated during prolonged in vitro culture of cardiomyocytes in floating cardiac bodies (soft conditions) vs. culture on a stiff matrix. Using a specific anti-β-MyHC and a newly generated anti-α-MyHC-antibody, we found individual cardiomyocytes grown in cardiac bodies to mostly express both α- and β-MyHC-protein isoforms. Yet, 35 and 75 days of cultivation on laminin-coated glass switched 66 and 87 % of all cardiomyocytes to exclusively express β-MyHC, respectively. Twitch contraction and calcium transients were faster for CMs on laminin-glass. Surprisingly, both parameters were only little affected by the MyHC-isoform, although hESC-CMs with only β-MyHC had much lower ATP-turnover and tension cost, just as in human ventricular cardiomyocytes. Spontaneous contractions and no strict coupling of β-MyHC to ventricular-like action potentials suggest that MyHC-isoform expression does not fully determine the hESC-CM differentiation status. Stiff substrate-induced pure β-MyHC-protein expression in hESC-CMs, with several contractile parameters close to ventricular cardiomyocytes, provides a well-defined in vitro system for modeling of cardiomyopathies and drug screening approaches.
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Affiliation(s)
- Natalie Weber
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Kristin Schwanke
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.,Leibniz Research Laboratories for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany.,HTTG, LEBAO and REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Stephan Greten
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Meike Wendland
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Bogdan Iorga
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany.,Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Martin Fischer
- Institute of Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Cornelia Geers-Knörr
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,REBIRTH Excellence Cluster, Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,REBIRTH Excellence Cluster, Hannover, Germany
| | - Jan Fiedler
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany
| | - Henning Kempf
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.,Leibniz Research Laboratories for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany.,HTTG, LEBAO and REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Annika Franke
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.,Leibniz Research Laboratories for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany.,HTTG, LEBAO and REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Birgit Piep
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Angelika Pfanne
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany
| | - Thomas Thum
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany.,Integrated Research and Treatment Center Transplantation (IFB-Tx) and REBIRTH Excellence Cluster, Hannover Medical School, Hannover, Germany.,National Heart and Lung Institute, Imperial College London, London, UK
| | - Ulrich Martin
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.,Leibniz Research Laboratories for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany.,HTTG, LEBAO and REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Bernhard Brenner
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany
| | - Robert Zweigerdt
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany. .,Leibniz Research Laboratories for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany. .,HTTG, LEBAO and REBIRTH-Center for Regenerative Medicine, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany.
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625, Hannover, Germany.
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49
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Cheng Y, Lindert S, Oxenford L, Tu AY, McCulloch AD, Regnier M. Effects of Cardiac Troponin I Mutation P83S on Contractile Properties and the Modulation by PKA-Mediated Phosphorylation. J Phys Chem B 2016; 120:8238-53. [PMID: 27150586 PMCID: PMC5001945 DOI: 10.1021/acs.jpcb.6b01859] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
cTnI(P82S) (cTnI(P83S) in rodents) resides at the I-T arm of cardiac troponin I (cTnI) and was initially identified as a disease-causing mutation of hypertrophic cardiomyopathy (HCM). However, later studies suggested this may not be true. We recently reported that introduction of an HCM-associated mutation in either inhibitory-peptide (cTnI(R146G)) or cardiac-specific N-terminus (cTnI(R21C)) of cTnI blunts the PKA-mediated modulation on myofibril activation/relaxation kinetics by prohibiting formation of intrasubunit contacts between these regions. Here, we tested whether this also occurs for cTnI(P83S). cTnI(P83S) increased both Ca(2+) binding affinity to cTn (KCa) and affinity of cTnC for cTnI (KC-I), and eliminated the reduction of KCa and KC-I observed for phosphorylated-cTnI(WT). In isolated myofibrils, cTnI(P83S) maintained maximal tension (TMAX) and Ca(2+) sensitivity of tension (pCa50). For cTnI(WT) myofibrils, PKA-mediated phosphorylation decreased pCa50 and sped up the slow-phase relaxation (especially for those Ca(2+) conditions that heart performs in vivo). Those effects were blunted for cTnI(P83S) myofibrils. Molecular-dynamics simulations suggested cTnI(P83S) moderately inhibited an intrasubunit interaction formation between inhibitory-peptide and N-terminus, but this "blunting" effect was weaker than that with cTnI(R146G) or cTnI(R21C). In summary, cTnI(P83S) has similar effects as other HCM-associated cTnI mutations on troponin and myofibril function even though it is in the I-T arm of cTnI.
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Affiliation(s)
- Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, United States
- National Biomedical Computation Resource, University of California San Diego, La Jolla, California 92093, United States
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Lucas Oxenford
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, United States
| | - An-yue Tu
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, United States
| | - Andrew D. McCulloch
- National Biomedical Computation Resource, University of California San Diego, La Jolla, California 92093, United States
- Department of Bioengineering, University of California San Diego, La Jolla, California 92093, United States
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, United States
- Center for Cardiovascular Biology, University of Washington, Seattle, Washington 98195, United States
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50
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Dvornikov AV, Smolin N, Zhang M, Martin JL, Robia SL, de Tombe PP. Restrictive Cardiomyopathy Troponin I R145W Mutation Does Not Perturb Myofilament Length-dependent Activation in Human Cardiac Sarcomeres. J Biol Chem 2016; 291:21817-21828. [PMID: 27557662 DOI: 10.1074/jbc.m116.746172] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/23/2016] [Indexed: 02/05/2023] Open
Abstract
The cardiac troponin I (cTnI) R145W mutation is associated with restrictive cardiomyopathy (RCM). Recent evidence suggests that this mutation induces perturbed myofilament length-dependent activation (LDA) under conditions of maximal protein kinase A (PKA) stimulation. Some cardiac disease-causing mutations, however, have been associated with a blunted response to PKA-mediated phosphorylation; whether this includes LDA is unknown. Endogenous troponin was exchanged in isolated skinned human myocardium for recombinant troponin containing either cTnI R145W, PKA/PKC phosphomimetic charge mutations (S23D/S24D and T143E), or various combinations thereof. Myofilament Ca2+ sensitivity of force, tension cost, LDA, and single myofibril activation/relaxation parameters were measured. Our results show that both R145W and T143E uncouple the impact of S23D/S24D phosphomimetic on myofilament function, including LDA. Molecular dynamics simulations revealed a marked reduction in interactions between helix C of cTnC (residues 56, 59, and 63), and cTnI (residue 145) in the presence of either cTnI RCM mutation or cTnI PKC phosphomimetic. These results suggest that the RCM-associated cTnI R145W mutation induces a permanent structural state that is similar to, but more extensive than, that induced by PKC-mediated phosphorylation of cTnI Thr-143. We suggest that this structural conformational change induces an increase in myofilament Ca2+ sensitivity and, moreover, uncoupling from the impact of phosphorylation of cTnI mediated by PKA at the Ser-23/Ser-24 target sites. The R145W RCM mutation by itself, however, does not impact LDA. These perturbed biophysical and biochemical myofilament properties are likely to significantly contribute to the diastolic cardiac pump dysfunction that is seen in patients suffering from a restrictive cardiomyopathy that is associated with the cTnI R145W mutation.
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Affiliation(s)
- Alexey V Dvornikov
- From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
| | - Nikolai Smolin
- From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
| | - Mengjie Zhang
- From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
| | - Jody L Martin
- From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
| | - Seth L Robia
- From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
| | - Pieter P de Tombe
- From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
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