1
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Song T, McNamara JW, Baby A, Ma W, Landim-Vieira M, Natesan S, Pinto JR, Lorenz JN, Irving TC, Sadayappan S. Unlocking the Role of sMyBP-C: A Key Player in Skeletal Muscle Development and Growth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563591. [PMID: 38076858 PMCID: PMC10705270 DOI: 10.1101/2023.10.23.563591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Skeletal muscle is the largest organ in the body, responsible for gross movement and metabolic regulation. Recently, variants in the MYBPC1 gene have been implicated in a variety of developmental muscle diseases, such as distal arthrogryposis. How MYBPC1 variants cause disease is not well understood. Here, through a collection of novel gene-edited mouse models, we define a critical role for slow myosin binding protein-C (sMyBP-C), encoded by MYBPC1, across muscle development, growth, and maintenance during prenatal, perinatal, postnatal and adult stages. Specifically, Mybpc1 knockout mice exhibited early postnatal lethality and impaired skeletal muscle formation and structure, skeletal deformity, and respiratory failure. Moreover, a conditional knockout of Mybpc1 in perinatal, postnatal and adult stages demonstrates impaired postnatal muscle growth and function secondary to disrupted actomyosin interaction and sarcomere structural integrity. These findings confirm the essential role of sMyBP-C in skeletal muscle and reveal specific functions in both prenatal embryonic musculoskeletal development and postnatal muscle growth and function.
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Affiliation(s)
- Taejeong Song
- Center for Cardiovascular Research, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - James W. McNamara
- Center for Cardiovascular Research, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Akhil Baby
- Center for Cardiovascular Research, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
- Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai, India
| | - Weikang Ma
- BioCAT, Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Sankar Natesan
- Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai, India
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - John N. Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Thomas C. Irving
- BioCAT, Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - Sakthivel Sadayappan
- Center for Cardiovascular Research, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
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2
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Vander Roest AS, Liu C, Morck MM, Kooiker KB, Jung G, Song D, Dawood A, Jhingran A, Pardon G, Ranjbarvaziri S, Fajardo G, Zhao M, Campbell KS, Pruitt BL, Spudich JA, Ruppel KM, Bernstein D. Hypertrophic cardiomyopathy β-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proc Natl Acad Sci U S A 2021. [PMID: 34117120 DOI: 10.1073/pnas.2025030118/suppl_file/pnas.2025030118.sm02.avi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in β-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.
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Affiliation(s)
- Alison Schroer Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Chao Liu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- School of Medicine, University of Washington, Seattle, WA 98109
| | - Gwanghyun Jung
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Dan Song
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Arnav Jhingran
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
| | - Gaspard Pardon
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Sara Ranjbarvaziri
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Giovanni Fajardo
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mingming Zhao
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY 40536
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Mechanical and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - James A Spudich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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3
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Vander Roest AS, Liu C, Morck MM, Kooiker KB, Jung G, Song D, Dawood A, Jhingran A, Pardon G, Ranjbarvaziri S, Fajardo G, Zhao M, Campbell KS, Pruitt BL, Spudich JA, Ruppel KM, Bernstein D. Hypertrophic cardiomyopathy β-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proc Natl Acad Sci U S A 2021; 118:e2025030118. [PMID: 34117120 PMCID: PMC8214707 DOI: 10.1073/pnas.2025030118] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in β-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.
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Affiliation(s)
- Alison Schroer Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Chao Liu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- School of Medicine, University of Washington, Seattle, WA 98109
| | - Gwanghyun Jung
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Dan Song
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Arnav Jhingran
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
| | - Gaspard Pardon
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Sara Ranjbarvaziri
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Giovanni Fajardo
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mingming Zhao
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY 40536
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Mechanical and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - James A Spudich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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4
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Electro-Mechanical Whole-Heart Digital Twins: A Fully Coupled Multi-Physics Approach. MATHEMATICS 2021. [DOI: 10.3390/math9111247] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mathematical models of the human heart are evolving to become a cornerstone of precision medicine and support clinical decision making by providing a powerful tool to understand the mechanisms underlying pathophysiological conditions. In this study, we present a detailed mathematical description of a fully coupled multi-scale model of the human heart, including electrophysiology, mechanics, and a closed-loop model of circulation. State-of-the-art models based on human physiology are used to describe membrane kinetics, excitation-contraction coupling and active tension generation in the atria and the ventricles. Furthermore, we highlight ways to adapt this framework to patient specific measurements to build digital twins. The validity of the model is demonstrated through simulations on a personalized whole heart geometry based on magnetic resonance imaging data of a healthy volunteer. Additionally, the fully coupled model was employed to evaluate the effects of a typical atrial ablation scar on the cardiovascular system. With this work, we provide an adaptable multi-scale model that allows a comprehensive personalization from ion channels to the organ level enabling digital twin modeling.
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5
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Blum KP, Campbell KS, Horslen BC, Nardelli P, Housley SN, Cope TC, Ting LH. Diverse and complex muscle spindle afferent firing properties emerge from multiscale muscle mechanics. eLife 2020; 9:e55177. [PMID: 33370235 PMCID: PMC7769569 DOI: 10.7554/elife.55177] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 12/04/2020] [Indexed: 11/13/2022] Open
Abstract
Despite decades of research, we lack a mechanistic framework capable of predicting how movement-related signals are transformed into the diversity of muscle spindle afferent firing patterns observed experimentally, particularly in naturalistic behaviors. Here, a biophysical model demonstrates that well-known firing characteristics of mammalian muscle spindle Ia afferents - including movement history dependence, and nonlinear scaling with muscle stretch velocity - emerge from first principles of muscle contractile mechanics. Further, mechanical interactions of the muscle spindle with muscle-tendon dynamics reveal how motor commands to the muscle (alpha drive) versus muscle spindle (gamma drive) can cause highly variable and complex activity during active muscle contraction and muscle stretch that defy simple explanation. Depending on the neuromechanical conditions, the muscle spindle model output appears to 'encode' aspects of muscle force, yank, length, stiffness, velocity, and/or acceleration, providing an extendable, multiscale, biophysical framework for understanding and predicting proprioceptive sensory signals in health and disease.
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Affiliation(s)
- Kyle P Blum
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
| | | | - Brian C Horslen
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
| | - Paul Nardelli
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Stephen N Housley
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Timothy C Cope
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Lena H Ting
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
- Department of Rehabilitation Medicine, Emory UniversityAtlantaUnited States
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6
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Campbell SG, Niederer SA. KBTBD13 and the ever-expanding sarcomeric universe. J Clin Invest 2020; 130:593-594. [PMID: 31904591 DOI: 10.1172/jci132954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
KBTBD13 is a protein expressed in striated muscle whose precise function is unknown. Work by de Winter et al. in this issue of the JCI provides evidence that KBTBD13 localizes to the sarcomere and can directly bind actin. A mutation in KBTBD13 that is associated with nemaline myopathy alters the protein's effects on actin, apparently increasing thin-filament stiffness and ultimately depressing contractile force and relaxation rate. We discuss here the implications of this new sarcomeric protein, some alternate explanations for the effects of KBTBD13R408C, and the advantages of using computational models to interpret functional data from muscle.
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Affiliation(s)
- Stuart G Campbell
- Departments of Biomedical Engineering and Cellular and Molecular Physiology, Yale University, New Haven, USA
| | - Steven A Niederer
- Department of Biomedical Engineering, Kings' College London, London, United Kingdom
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7
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Kadry K, Pagoulatou S, Mercier Q, Rovas G, Bikia V, Müller H, Adamopoulos D, Stergiopulos N. Biomechanics of diastolic dysfunction: a one-dimensional computational modeling approach. Am J Physiol Heart Circ Physiol 2020; 319:H882-H892. [PMID: 32822212 DOI: 10.1152/ajpheart.00172.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Diastolic dysfunction (DD) is a major component of heart failure with preserved ejection fraction (HFpEF). Accordingly, a profound understanding of the underlying biomechanical mechanisms involved in DD is needed to elucidate all aspects of HFpEF. In this study, we have developed a computational model of DD by leveraging the power of an advanced one-dimensional arterial network coupled to a four-chambered zero-dimensional cardiac model. The two main pathologies investigated were linked to the active relaxation of the myocardium and the passive stiffness of the left ventricular wall. These pathologies were quantified through two parameters for the biphasic delay of active relaxation, which simulate the early and late-phase relaxation delay, and one parameter for passive stiffness, which simulates the increased nonlinear stiffness of the ventricular wall. A parameter sensitivity analysis was conducted on each of the three parameters to investigate their effect in isolation. The three parameters were then concurrently adjusted to produce the three main phenotypes of DD. It was found that the impaired relaxation phenotype can be replicated by mainly manipulating the active relaxation, the pseudo-normal phenotype was replicated by manipulating both the active relaxation and passive stiffness, and, finally, the restricted phenotype was replicated by mainly changing the passive stiffness. This article presents a simple model producing a holistic and comprehensive replication of the main DD phenotypes and presents novel biomechanical insights on how key parameters defining the relaxation and stiffness properties of the myocardium affect the development and manifestation of DD.NEW & NOTEWORTHY This study uses a complete and validated computational model of the cardiovascular system to simulate the two main pathologies involved in diastolic dysfunction (DD), i.e., abnormal active relaxation and increased ventricular diastolic stiffness. The three phenotypes of DD were successfully replicated according to literature data. We elucidate the biomechanical effect of the relaxation pathologies involved and how these pathologies interact to create the various phenotypes of DD.
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Affiliation(s)
- Karim Kadry
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Stamatia Pagoulatou
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Quentin Mercier
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Georgios Rovas
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Vasiliki Bikia
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Hajo Müller
- Department of Cardiology, Hôpitaux Universitaires de Genève, Geneva, Switzerland
| | | | - Nikolaos Stergiopulos
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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8
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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: 27] [Impact Index Per Article: 6.8] [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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9
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Lin DC, McGowan CP, Blum KP, Ting LH. Yank: the time derivative of force is an important biomechanical variable in sensorimotor systems. ACTA ACUST UNITED AC 2019; 222:222/18/jeb180414. [PMID: 31515280 DOI: 10.1242/jeb.180414] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The derivative of force with respect to time does not have a standard term in physics. As a consequence, the quantity has been given a variety of names, the most closely related being 'rate of force development'. The lack of a proper name has made it difficult to understand how different structures and processes within the sensorimotor system respond to and shape the dynamics of force generation, which is critical for survival in many species. We advocate that ∂[Formula: see text]/∂t be termed 'yank', a term that has previously been informally used and never formally defined. Our aim in this Commentary is to establish the significance of yank in how biological motor systems are organized, evolve and adapt. Further, by defining the quantity in mathematical terms, several measurement variables that are commonly reported can be clarified and unified. In this Commentary, we first detail the many types of motor function that are affected by the magnitude of yank generation, especially those related to time-constrained activities. These activities include escape, prey capture and postural responses to perturbations. Next, we describe the multi-scale structures and processes of the musculoskeletal system that influence yank and can be modified to increase yank generation. Lastly, we highlight recent studies showing that yank is represented in the sensory feedback system, and discuss how this information is used to enhance postural stability and facilitate recovery from postural perturbations. Overall, we promote an increased consideration of yank in studying biological motor and sensory systems.
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Affiliation(s)
- David C Lin
- School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA .,Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - Craig P McGowan
- Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA.,Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA.,WWAMI Medical Education Program, Moscow, ID 83844, USA
| | - Kyle P Blum
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Lena H Ting
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.,Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA 30322, USA
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10
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How myofilament strain and strain rate lead the dance of the cardiac cycle. Arch Biochem Biophys 2019; 664:62-67. [PMID: 30710504 PMCID: PMC6589344 DOI: 10.1016/j.abb.2019.01.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/21/2019] [Accepted: 01/28/2019] [Indexed: 12/20/2022]
Abstract
Movement of the myocardium can modify organ-level cardiac function and its molecular (crossbridge) mechanisms. This motion, which is defined by myocardial strain and strain rate (muscle shortening, lengthening, and the speed of these movements), occurs throughout the cardiac cycle, including during isovolumic periods. This review highlights how the left ventricular myocardium moves throughout the cardiac cycle, how muscle mechanics experiments provide insight into the regulation of forces used to move blood in and out of the left ventricle, and its impact on (and regulation by) crossbridge and sarcomere kinetics. We specifically highlight how muscle mechanics experiments explain how myocardial relaxation is accelerated by lengthening (strain rate) during late systole and isovolumic relaxation, a lengthening which has been measured in human hearts. Advancing and refining both in vivo measurement and ex vivo protocols with physiologic strain and strain rates could reveal important insights into molecular (crossbridge) kinetics. These advances could provide an improvement in both diagnosis and precise treatment of cardiac dysfunction.
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11
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Clark JA, Campbell SG. Diverse relaxation rates exist among rat cardiomyocytes isolated from a single myocardial region. J Physiol 2018; 597:711-722. [PMID: 30315728 DOI: 10.1113/jp276718] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/27/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Prior studies have shown variation in the functional properties of cardiomyocytes isolated from different regions of the left ventricular myocardium. We found that these region-dependent variations vanish below a tissue volume of ∼7 mm3 in the adult rat myocardium, revealing a fixed level of intrinsic relaxation rate heterogeneity that is independent of tissue volume. Within these microscopically varying cell populations, fast-relaxing cells were shown to have elevated phosphorylated troponin I compared to slow-relaxing cells. Relaxation rate was also correlated with cardiomyocyte length, in that slow-relaxing cells were longer than fast-relaxing cells. These results show a new relationship between cardiomyocyte morphology and myofilament relaxation, and suggest that functional diversity among individual myocytes at the microscale may contribute to bulk relaxation of the myocardium. ABSTRACT The mean contractility and calcium handling properties of cardiomyocytes isolated from different regions of the ventricular myocardium are known to vary significantly. We designed experiments to quantify the variance in contractile properties among cells within the same myocardial region. Longitudinal strips of myocardial tissue were excised from the epicardial left ventricular free walls of adult Sprague-Dawley rats and then treated with collagenase to isolate individual myocytes. Cardiomyocytes were characterized by measuring sarcomere length changes and calcium transients during electrical pacing. Variance of the time from peak sarcomere shortening to 50% re-lengthening (RT50 ) was assessed in each cell population. Isolating cells from progressively shorter strips allowed an estimate of the myocardial volume below which regional variation vanished and only microscale heterogeneity remained (∼7 mm3 ). The SD of RT50 within this myocardial volume was 28% of the mean. In a series of follow-up experiments, RT50 was shown to correlate significantly with resting myocyte length, suggesting a connection between cell morphology and intrinsic relaxation behaviour. To explore the mechanistic basis of varying RT50 , a novel single-cell aspirator was employed to collect small batches of cardiomyocytes grouped according to their relaxation rates (fast or slow). Western blot analysis of the two groups revealed significantly elevated troponin I phosphorylation in fast-relaxing cells. Our observations suggest that cell-to-cell heterogeneity of active contractile properties is substantial, with implications for how we understand myocardial relaxation and design drug therapies intended to alter relaxation rate.
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12
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Jarvis K, Woodward M, Debold EP, Walcott S. Acidosis affects muscle contraction by slowing the rates myosin attaches to and detaches from actin. J Muscle Res Cell Motil 2018; 39:135-147. [PMID: 30382520 DOI: 10.1007/s10974-018-9499-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/19/2018] [Indexed: 11/24/2022]
Abstract
The loss of muscle force and power during fatigue from intense contractile activity is associated with, and likely caused by, elevated levels of phosphate ([Formula: see text]) and hydrogen ions (decreased pH). To understand how these deficits in muscle performance occur at the molecular level, we used direct measurements of mini-ensembles of myosin generating force in the laser trap assay at pH 7.4 and 6.5. The data are consistent with a mechanochemical model in which a decrease in pH reduces myosin's detachment from actin (by slowing ADP release), increases non-productive myosin binding (by detached myosin rebinding without a powerstroke), and reduces myosin's attachment to actin (by slowing the weak-to-strong binding transition). Additional support of this mechanism is found by incorporating it into a branched pathway model for the effects of [Formula: see text] on myosin's interaction with actin. Including pH-dependence in one additional parameter (acceleration of [Formula: see text]-induced detachment), the model reproduces experimental measurements at high and low pH, and variable [Formula: see text], from the single molecule to large ensemble levels. Furthermore, when scaled up, the model predicts force-velocity relationships that are consistent with muscle fiber measurements. The model suggests that reducing pH has two opposing effects, a decrease in attachment favoring a decrease in muscle force and a decrease in detachment favoring an increase in muscle force. Depending on experimental details, the addition of [Formula: see text] can strengthen one or the other effect, resulting in either synergistic or antagonistic effects. This detailed molecular description suggests a molecular basis for contractile failure during muscle fatigue.
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Affiliation(s)
- Katelyn Jarvis
- Department of Mathematics, University of California, Davis, Davis, CA, 95616, USA
| | - Mike Woodward
- Department of Kinesiology, University of Massachusetts, Amherst, Amherst, MA, 01003, USA
| | - Edward P Debold
- Department of Kinesiology, University of Massachusetts, Amherst, Amherst, MA, 01003, USA
| | - Sam Walcott
- Department of Mathematics, University of California, Davis, Davis, CA, 95616, USA.
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13
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Coq JO, Delcour M, Ogawa Y, Peyronnet J, Castets F, Turle-Lorenzo N, Montel V, Bodineau L, Cardot P, Brocard C, Liabeuf S, Bastide B, Canu MH, Tsuji M, Cayetanot F. Mild Intrauterine Hypoperfusion Leads to Lumbar and Cortical Hyperexcitability, Spasticity, and Muscle Dysfunctions in Rats: Implications for Prematurity. Front Neurol 2018; 9:423. [PMID: 29973904 PMCID: PMC6020763 DOI: 10.3389/fneur.2018.00423] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/22/2018] [Indexed: 12/22/2022] Open
Abstract
Intrauterine ischemia-hypoxia is detrimental to the developing brain and leads to white matter injury (WMI), encephalopathy of prematurity (EP), and often to cerebral palsy (CP), but the related pathophysiological mechanisms remain unclear. In prior studies, we used mild intrauterine hypoperfusion (MIUH) in rats to successfully reproduce the diversity of clinical signs of EP, and some CP symptoms. Briefly, MIUH led to inflammatory processes, diffuse gray and WMI, minor locomotor deficits, musculoskeletal pathologies, neuroanatomical and functional disorganization of the primary somatosensory and motor cortices, delayed sensorimotor reflexes, spontaneous hyperactivity, deficits in sensory information processing, memory and learning impairments. In the present study, we investigated the early and long-lasting mechanisms of pathophysiology that may be responsible for the various symptoms induced by MIUH. We found early hyperreflexia, spasticity and reduced expression of KCC2 (a chloride cotransporter that regulates chloride homeostasis and cell excitability). Adult MIUH rats exhibited changes in muscle contractile properties and phenotype, enduring hyperreflexia and spasticity, as well as hyperexcitability in the sensorimotor cortex. Taken together, these results show that reduced expression of KCC2, lumbar hyperreflexia, spasticity, altered properties of the soleus muscle, as well as cortical hyperexcitability may likely interplay into a self-perpetuating cycle, leading to the emergence, and persistence of neurodevelopmental disorders (NDD) in EP and CP, such as sensorimotor impairments, and probably hyperactivity, attention, and learning disorders.
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Affiliation(s)
- Jacques-Olivier Coq
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France.,Centre National de la Recherche Scientifique, Neurosciences Intégratives et Adaptatives, UMR 7260, Aix Marseille Université, Marseille, France
| | - Maxime Delcour
- Centre National de la Recherche Scientifique, Neurosciences Intégratives et Adaptatives, UMR 7260, Aix Marseille Université, Marseille, France
| | - Yuko Ogawa
- Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Julie Peyronnet
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France
| | - Francis Castets
- Centre National de la Recherche Scientifique, Institut de Biologie du Développement de Marseille, UMR 7288, Aix-Marseille Université, Marseille, France
| | - Nathalie Turle-Lorenzo
- FR 3512 Fédération 3C, Aix Marseille Université - Centre National de la Recherche Scientifique, Marseille, France
| | - Valérie Montel
- EA 7369 ≪Activité Physique, Muscle et Santé≫ - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Université de Lille, Lille, France
| | - Laurence Bodineau
- Institut National de la Santé et de la Recherche Médicale, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
| | - Phillipe Cardot
- Institut National de la Santé et de la Recherche Médicale, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
| | - Cécile Brocard
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France
| | - Sylvie Liabeuf
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France
| | - Bruno Bastide
- EA 7369 ≪Activité Physique, Muscle et Santé≫ - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Université de Lille, Lille, France
| | - Marie-Hélène Canu
- EA 7369 ≪Activité Physique, Muscle et Santé≫ - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Université de Lille, Lille, France
| | - Masahiro Tsuji
- Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Florence Cayetanot
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France.,Institut National de la Santé et de la Recherche Médicale, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
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14
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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: 113] [Impact Index Per Article: 16.1] [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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15
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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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16
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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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17
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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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18
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Mayfield DL, Launikonis BS, Cresswell AG, Lichtwark GA. Additional in-series compliance reduces muscle force summation and alters the time course of force relaxation during fixed-end contractions. ACTA ACUST UNITED AC 2016; 219:3587-3596. [PMID: 27609762 DOI: 10.1242/jeb.143123] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/31/2016] [Indexed: 02/06/2023]
Abstract
There are high mechanical demands placed on skeletal muscles in movements requiring rapid acceleration of the body or its limbs. Tendons are responsible for transmitting muscle forces, but, because of their elasticity, can manipulate the mechanics of the internal contractile apparatus. Shortening of the contractile apparatus against the stretch of tendon affects force generation according to known mechanical properties; however, the extent to which differences in tendon compliance alter force development in response to a burst of electrical impulses is unclear. To establish the influence of series compliance on force summation, we studied electrically evoked doublet contractions in the cane toad peroneus muscle in the presence and absence of a compliant artificial tendon. Additional series compliance reduced tetanic force by two-thirds, a finding predicted based on the force-length property of skeletal muscle. Doublet force and force-time integral expressed relative to the twitch were also reduced by additional series compliance. Active shortening over a larger range of the ascending limb of the force-length curve and at a higher velocity, leading to a progressive reduction in force-generating potential, could be responsible. Muscle-tendon interaction may also explain the accelerated time course of force relaxation in the presence of additional compliance. Our findings suggest that a compliant tendon limits force summation under constant-length conditions. However, high series compliance can be mechanically advantageous when a muscle-tendon unit is actively stretched, permitting muscle fibres to generate force almost isometrically, as shown during stretch-shorten cycles in locomotor activities. Restricting active shortening would likely favour rapid force development.
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Affiliation(s)
- Dean L Mayfield
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Andrew G Cresswell
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Glen A Lichtwark
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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19
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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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20
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Pulcastro HC, Awinda PO, Methawasin M, Granzier H, Dong W, Tanner BCW. Increased Titin Compliance Reduced Length-Dependent Contraction and Slowed Cross-Bridge Kinetics in Skinned Myocardial Strips from Rbm (20ΔRRM) Mice. Front Physiol 2016; 7:322. [PMID: 27524973 PMCID: PMC4966298 DOI: 10.3389/fphys.2016.00322] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/14/2016] [Indexed: 01/12/2023] Open
Abstract
Titin is a giant protein spanning from the Z-disk to the M-band of the cardiac sarcomere. In the I-band titin acts as a molecular spring, contributing to passive mechanical characteristics of the myocardium throughout a heartbeat. RNA Binding Motif Protein 20 (RBM20) is required for normal titin splicing, and its absence or altered function leads to greater expression of a very large, more compliant N2BA titin isoform in Rbm20 homozygous mice (Rbm20ΔRRM) compared to wild-type mice (WT) that almost exclusively express the stiffer N2B titin isoform. Prior studies using Rbm20ΔRRM animals have shown that increased titin compliance compromises muscle ultrastructure and attenuates the Frank-Starling relationship. Although previous computational simulations of muscle contraction suggested that increasing compliance of the sarcomere slows the rate of tension development and prolongs cross-bridge attachment, none of the reported effects of Rbm20ΔRRM on myocardial function have been attributed to changes in cross-bridge cycling kinetics. To test the relationship between increased sarcomere compliance and cross-bridge kinetics, we used stochastic length-perturbation analysis in Ca2+-activated, skinned papillary muscle strips from Rbm20ΔRRM and WT mice. We found increasing titin compliance depressed maximal tension, decreased Ca2+-sensitivity of the tension-pCa relationship, and slowed myosin detachment rate in myocardium from Rbm20ΔRRM vs. WT mice. As sarcomere length increased from 1.9 to 2.2 μm, length-dependent activation of contraction was eliminated in the Rbm20ΔRRM myocardium, even though myosin MgADP release rate decreased ~20% to prolong strong cross-bridge binding at longer sarcomere length. These data suggest that increasing N2BA expression may alter cardiac performance in a length-dependent manner, showing greater deficits in tension production and slower cross-bridge kinetics at longer sarcomere length. This study also supports the idea that passive mechanical characteristics of the myocardium influence ensemble cross-bridge behavior and maintenance of tension generation throughout the sarcomere.
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Affiliation(s)
- Hannah C Pulcastro
- Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Peter O Awinda
- Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona Tucson, AZ, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona Tucson, AZ, USA
| | - Wenji Dong
- Department of Integrative Physiology and Neuroscience, Washington State UniversityPullman, WA, USA; Voiland School of Chemical Engineering and Bioengineering, Washington State UniversityPullman, WA, USA
| | - Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
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