1
|
Liu S, Marang C, Woodward M, Joumaa V, Leonard T, Scott B, Debold E, Herzog W, Walcott S. Modeling thick filament activation suggests a molecular basis for force depression. Biophys J 2024; 123:555-571. [PMID: 38291752 PMCID: PMC10938083 DOI: 10.1016/j.bpj.2024.01.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/05/2023] [Accepted: 01/22/2024] [Indexed: 02/01/2024] Open
Abstract
Multiscale models aiming to connect muscle's molecular and cellular function have been difficult to develop, in part due to a lack of self-consistent multiscale data. To address this gap, we measured the force response from single, skinned rabbit psoas muscle fibers to ramp shortenings and step stretches performed on the plateau region of the force-length relationship. We isolated myosin from the same muscles and, under similar conditions, performed single-molecule and ensemble measurements of myosin's ATP-dependent interaction with actin using laser trapping and in vitro motility assays. We fit the fiber data by developing a partial differential equation model that includes thick filament activation, whereby an increase in force on the thick filament pulls myosin out of an inhibited state. The model also includes a series elastic element and a parallel elastic element. This parallel elastic element models a titin-actin interaction proposed to account for the increase in isometric force after stretch (residual force enhancement). By optimizing the model fit to a subset of our fiber measurements, we specified seven unknown parameters. The model then successfully predicted the remainder of our fiber measurements and also our molecular measurements from the laser trap and in vitro motility. The success of the model suggests that our multiscale data are self-consistent and can serve as a testbed for other multiscale models. Moreover, the model captures the decrease in isometric force observed in our muscle fibers after active shortening (force depression), suggesting a molecular mechanism for force depression, whereby a parallel elastic element combines with thick filament activation to decrease the number of cycling cross-bridges.
Collapse
Affiliation(s)
- Shuyue Liu
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta
| | - Chris Marang
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Mike Woodward
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Venus Joumaa
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta
| | - Tim Leonard
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta
| | - Brent Scott
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Edward Debold
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Walter Herzog
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta
| | - Sam Walcott
- Mathematical Sciences, Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, Massachusetts.
| |
Collapse
|
2
|
Garg A, Lavine KJ, Greenberg MJ. Assessing Cardiac Contractility From Single Molecules to Whole Hearts. JACC Basic Transl Sci 2024; 9:414-439. [PMID: 38559627 PMCID: PMC10978360 DOI: 10.1016/j.jacbts.2023.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/14/2023] [Accepted: 07/14/2023] [Indexed: 04/04/2024]
Abstract
Fundamentally, the heart needs to generate sufficient force and power output to dynamically meet the needs of the body. Cardiomyocytes contain specialized structures referred to as sarcomeres that power and regulate contraction. Disruption of sarcomeric function or regulation impairs contractility and leads to cardiomyopathies and heart failure. Basic, translational, and clinical studies have adapted numerous methods to assess cardiac contraction in a variety of pathophysiological contexts. These tools measure aspects of cardiac contraction at different scales ranging from single molecules to whole organisms. Moreover, these studies have revealed new pathogenic mechanisms of heart disease leading to the development of novel therapies targeting contractility. In this review, the authors explore the breadth of tools available for studying cardiac contractile function across scales, discuss their strengths and limitations, highlight new insights into cardiac physiology and pathophysiology, and describe how these insights can be harnessed for therapeutic candidate development and translational.
Collapse
Affiliation(s)
- Ankit Garg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Cardiovascular Research, Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kory J. Lavine
- Center for Cardiovascular Research, Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael J. Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| |
Collapse
|
3
|
Ottaviani A, Mansour D, Molinari LV, Galanti K, Mantini C, Khanji MY, Chahal AA, Zimarino M, Renda G, Sciarra L, Pelliccia F, Gallina S, Ricci F. Revisiting Diagnosis and Treatment of Hypertrophic Cardiomyopathy: Current Practice and Novel Perspectives. J Clin Med 2023; 12:5710. [PMID: 37685777 PMCID: PMC10489039 DOI: 10.3390/jcm12175710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/26/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
Sarcomeric hypertrophic cardiomyopathy (HCM) is a prevalent genetic disorder characterised by left ventricular hypertrophy, myocardial disarray, and an increased risk of heart failure and sudden cardiac death. Despite advances in understanding its pathophysiology, treatment options for HCM remain limited. This narrative review aims to provide a comprehensive overview of current clinical practice and explore emerging therapeutic strategies for sarcomeric HCM, with a focus on cardiac myosin inhibitors. We first discuss the conventional management of HCM, including lifestyle modifications, pharmacological therapies, and invasive interventions, emphasizing their limitations and challenges. Next, we highlight recent advances in molecular genetics and their potential applications in refining HCM diagnosis, risk stratification, and treatment. We delve into emerging therapies, such as gene editing, RNA-based therapies, targeted small molecules, and cardiac myosin modulators like mavacamten and aficamten, which hold promise in modulating the underlying molecular mechanisms of HCM. Mavacamten and aficamten, selective modulators of cardiac myosin, have demonstrated encouraging results in clinical trials by reducing left ventricular outflow tract obstruction and improving symptoms in patients with obstructive HCM. We discuss their mechanisms of action, clinical trial outcomes, and potential implications for the future of HCM management. Furthermore, we examine the role of precision medicine in HCM management, exploring how individualised treatment strategies, including exercise prescription as part of the management plan, may optimise patient outcomes. Finally, we underscore the importance of multidisciplinary care and patient-centred approaches to address the complex needs of HCM patients. This review also aims to encourage further research and collaboration in the field of HCM, promoting the development of novel and more effective therapeutic strategies, such as cardiac myosin modulators, to hopefully improve the quality of life and outcome of patients with sarcomeric HCM.
Collapse
Affiliation(s)
- Andrea Ottaviani
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Davide Mansour
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Lorenzo V. Molinari
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Kristian Galanti
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Cesare Mantini
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Mohammed Y. Khanji
- Barts Heart Centre, Barts Health NHS Trust, London EC1A 7BE, UK
- Newham University Hospital, Barts Health NHS Trust, London E13 8SL, UK
- NIHR Barts Biomedical Research Centre, William Harvey Research Institute, Queen Mary University of London, London EC1A 7BE, UK
| | - Anwar A. Chahal
- Barts Heart Centre, Barts Health NHS Trust, London EC1A 7BE, UK
- Inherited Cardiovascular Diseases, WellSpan Health, Lancaster, PA 17605, USA
- Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA 17605, USA
| | - Marco Zimarino
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
- Heart Department, SS. Annunziata Hospital, ASL 2 Abruzzo, 66100 Chieti, Italy
| | - Giulia Renda
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
- Heart Department, SS. Annunziata Hospital, ASL 2 Abruzzo, 66100 Chieti, Italy
| | - Luigi Sciarra
- Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Francesco Pelliccia
- Department of Cardiovascular Sciences, Sapienza University, 00166 Rome, Italy
| | - Sabina Gallina
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
- Heart Department, SS. Annunziata Hospital, ASL 2 Abruzzo, 66100 Chieti, Italy
| | - Fabrizio Ricci
- Department of Neuroscience, Imaging and Clinical Sciences, “G. D’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
- Heart Department, SS. Annunziata Hospital, ASL 2 Abruzzo, 66100 Chieti, Italy
- Department of Clinical Sciences, Lund University, 21428 Malmö, Sweden
| |
Collapse
|
4
|
Halder SS, Rynkiewicz MJ, Creso JG, Sewanan LR, Howland L, Moore JR, Lehman W, Campbell SG. Mechanisms of pathogenicity in the hypertrophic cardiomyopathy-associated TPM1 variant S215L. PNAS NEXUS 2023; 2:pgad011. [PMID: 36896133 PMCID: PMC9991458 DOI: 10.1093/pnasnexus/pgad011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/12/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is an inherited disorder often caused by mutations to sarcomeric genes. Many different HCM-associated TPM1 mutations have been identified but they vary in their degrees of severity, prevalence, and rate of disease progression. The pathogenicity of many TPM1 variants detected in the clinical population remains unknown. Our objective was to employ a computational modeling pipeline to assess pathogenicity of one such variant of unknown significance, TPM1 S215L, and validate predictions using experimental methods. Molecular dynamic simulations of tropomyosin on actin suggest that the S215L significantly destabilizes the blocked regulatory state while increasing flexibility of the tropomyosin chain. These changes were quantitatively represented in a Markov model of thin-filament activation to infer the impacts of S215L on myofilament function. Simulations of in vitro motility and isometric twitch force predicted that the mutation would increase Ca2+ sensitivity and twitch force while slowing twitch relaxation. In vitro motility experiments with thin filaments containing TPM1 S215L revealed higher Ca2+ sensitivity compared with wild type. Three-dimensional genetically engineered heart tissues expressing TPM1 S215L exhibited hypercontractility, upregulation of hypertrophic gene markers, and diastolic dysfunction. These data form a mechanistic description of TPM1 S215L pathogenicity that starts with disruption of the mechanical and regulatory properties of tropomyosin, leading thereafter to hypercontractility and finally induction of a hypertrophic phenotype. These simulations and experiments support the classification of S215L as a pathogenic mutation and support the hypothesis that an inability to adequately inhibit actomyosin interactions is the mechanism whereby thin-filament mutations cause HCM.
Collapse
Affiliation(s)
- Saiti S Halder
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511
| | | | - Jenette G Creso
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511
| | - Lorenzo R Sewanan
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511
- Department of Internal Medicine, Columbia University, New York, NY 10032
| | - Lindsey Howland
- Department of Biological Sciences, University of Massachusetts Lowell, MA 01854
| | - Jeffrey R Moore
- Department of Biological Sciences, University of Massachusetts Lowell, MA 01854
| | - William Lehman
- Department of Physiology/Biophysics, Boston University, Boston, MA 02215
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511
| |
Collapse
|
5
|
Abstract
Hypertrophic cardiomyopathy (HCM), the most common inherited heart disease, is still orphan of a specific drug treatment. The erroneous consideration of HCM as a rare disease has hampered the design and conduct of large, randomized trials in the last 50 years, and most of the indications in the current guidelines are derived from small non-randomized studies, case series, or simply from the consensus of experts. Guideline-directed therapy of HCM includes non-selective drugs such as disopyramide, non-dihydropyridine calcium channel blockers, or β-adrenergic receptor blockers, mainly used in patients with symptomatic obstruction of the outflow tract. Following promising preclinical studies, several drugs acting on potential HCM-specific targets were tested in patients. Despite the huge efforts, none of these studies was able to change clinical practice for HCM patients, because tested drugs were proven to be scarcely effective or hardly tolerated in patients. However, novel compounds have been developed in recent years specifically for HCM, addressing myocardial hypercontractility and altered energetics in a direct manner, through allosteric inhibition of myosin. In this paper, we will critically review the use of different classes of drugs in HCM patients, starting from "old" established agents up to novel selective drugs that have been recently trialed in patients.
Collapse
|
6
|
Riaz M, Park J, Sewanan LR, Ren Y, Schwan J, Das SK, Pomianowski PT, Huang Y, Ellis MW, Luo J, Liu J, Song L, Chen IP, Qiu C, Yazawa M, Tellides G, Hwa J, Young LH, Yang L, Marboe CC, Jacoby DL, Campbell SG, Qyang Y. Muscle LIM Protein Force-Sensing Mediates Sarcomeric Biomechanical Signaling in Human Familial Hypertrophic Cardiomyopathy. Circulation 2022; 145:1238-1253. [PMID: 35384713 PMCID: PMC9109819 DOI: 10.1161/circulationaha.121.056265] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Familial hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease and is typically caused by mutations in genes encoding sarcomeric proteins that regulate cardiac contractility. HCM manifestations include left ventricular hypertrophy and heart failure, arrythmias, and sudden cardiac death. How dysregulated sarcomeric force production is sensed and leads to pathological remodeling remains poorly understood in HCM, thereby inhibiting the efficient development of new therapeutics. METHODS Our discovery was based on insights from a severe phenotype of an individual with HCM and a second genetic alteration in a sarcomeric mechanosensing protein. We derived cardiomyocytes from patient-specific induced pluripotent stem cells and developed robust engineered heart tissues by seeding induced pluripotent stem cell-derived cardiomyocytes into a laser-cut scaffold possessing native cardiac fiber alignment to study human cardiac mechanobiology at both the cellular and tissue levels. Coupled with computational modeling for muscle contraction and rescue of disease phenotype by gene editing and pharmacological interventions, we have identified a new mechanotransduction pathway in HCM, shown to be essential in modulating the phenotypic expression of HCM in 5 families bearing distinct sarcomeric mutations. RESULTS Enhanced actomyosin crossbridge formation caused by sarcomeric mutations in cardiac myosin heavy chain (MYH7) led to increased force generation, which, when coupled with slower twitch relaxation, destabilized the MLP (muscle LIM protein) stretch-sensing complex at the Z-disc. Subsequent reduction in the sarcomeric muscle LIM protein level caused disinhibition of calcineurin-nuclear factor of activated T-cells signaling, which promoted cardiac hypertrophy. We demonstrate that the common muscle LIM protein-W4R variant is an important modifier, exacerbating the phenotypic expression of HCM, but alone may not be a disease-causing mutation. By mitigating enhanced actomyosin crossbridge formation through either genetic or pharmacological means, we alleviated stress at the Z-disc, preventing the development of hypertrophy associated with sarcomeric mutations. CONCLUSIONS Our studies have uncovered a novel biomechanical mechanism through which dysregulated sarcomeric force production is sensed and leads to pathological signaling, remodeling, and hypertrophic responses. Together, these establish the foundation for developing innovative mechanism-based treatments for HCM that stabilize the Z-disc MLP-mechanosensory complex.
Collapse
Affiliation(s)
- Muhammad Riaz
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Jinkyu Park
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Lorenzo R. Sewanan
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Yongming Ren
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Jonas Schwan
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Subhash K. Das
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | | | - Yan Huang
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Matthew W. Ellis
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Jiesi Luo
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Juli Liu
- Department of Pediatrics, Anatomy and Cell Biology, Indiana University, Indianapolis, IN, USA
| | - Loujin Song
- Department of Rehabilitation and Regenerative Medicine, Columbia Stem Cell Initiative, Columbia University, New York, NY, USA
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
| | - I-Ping Chen
- Department of Oral Health and Diagnostic Sciences, University of Connecticut Health, Farmington, CT, USA
| | | | - Masayuki Yazawa
- Department of Rehabilitation and Regenerative Medicine, Columbia Stem Cell Initiative, Columbia University, New York, NY, USA
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
| | | | - John Hwa
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Lawrence H. Young
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Lei Yang
- Department of Pediatrics, Anatomy and Cell Biology, Indiana University, Indianapolis, IN, USA
| | - Charles C. Marboe
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Daniel L. Jacoby
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Stuart G. Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Yibing Qyang
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| |
Collapse
|
7
|
Parikh J, Rumbell T, Butova X, Myachina T, Acero JC, Khamzin S, Solovyova O, Kozloski J, Khokhlova A, Gurev V. Generative adversarial networks for construction of virtual populations of mechanistic models: simulations to study Omecamtiv Mecarbil action. J Pharmacokinet Pharmacodyn 2021; 49:51-64. [PMID: 34716531 PMCID: PMC8837558 DOI: 10.1007/s10928-021-09787-4] [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: 06/21/2021] [Accepted: 09/23/2021] [Indexed: 11/30/2022]
Abstract
Biophysical models are increasingly used to gain mechanistic insights by fitting and reproducing experimental and clinical data. The inherent variability in the recorded datasets, however, presents a key challenge. In this study, we present a novel approach, which integrates mechanistic modeling and machine learning to analyze in vitro cardiac mechanics data and solve the inverse problem of model parameter inference. We designed a novel generative adversarial network (GAN) and employed it to construct virtual populations of cardiac ventricular myocyte models in order to study the action of Omecamtiv Mecarbil (OM), a positive cardiac inotrope. Populations of models were calibrated from mechanically unloaded myocyte shortening recordings obtained in experiments on rat myocytes in the presence and absence of OM. The GAN was able to infer model parameters while incorporating prior information about which model parameters OM targets. The generated populations of models reproduced variations in myocyte contraction recorded during in vitro experiments and provided improved understanding of OM’s mechanism of action. Inverse mapping of the experimental data using our approach suggests a novel action of OM, whereby it modifies interactions between myosin and tropomyosin proteins. To validate our approach, the inferred model parameters were used to replicate other in vitro experimental protocols, such as skinned preparations demonstrating an increase in calcium sensitivity and a decrease in the Hill coefficient of the force–calcium (F–Ca) curve under OM action. Our approach thereby facilitated the identification of the mechanistic underpinnings of experimental observations and the exploration of different hypotheses regarding variability in this complex biological system.
Collapse
Affiliation(s)
| | | | - Xenia Butova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences (UB RAS), Yekaterinburg, Russia
| | - Tatiana Myachina
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences (UB RAS), Yekaterinburg, Russia
| | - Jorge Corral Acero
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Svyatoslav Khamzin
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences (UB RAS), Yekaterinburg, Russia
| | - Olga Solovyova
- Ural Federal University, Yekaterinburg, Russia.,Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences (UB RAS), Yekaterinburg, Russia
| | | | - Anastasia Khokhlova
- Ural Federal University, Yekaterinburg, Russia.,Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences (UB RAS), Yekaterinburg, Russia
| | | |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Sewanan LR, Park J, Rynkiewicz MJ, Racca AW, Papoutsidakis N, Schwan J, Jacoby DL, Moore JR, Lehman W, Qyang Y, Campbell SG. Loss of crossbridge inhibition drives pathological cardiac hypertrophy in patients harboring the TPM1 E192K mutation. J Gen Physiol 2021; 153:212516. [PMID: 34319370 PMCID: PMC8321830 DOI: 10.1085/jgp.202012640] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/14/2021] [Accepted: 07/09/2021] [Indexed: 01/10/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is an inherited disorder caused primarily by mutations to thick and thinfilament proteins. Although thin filament mutations are less prevalent than their oft-studied thick filament counterparts, they are frequently associated with severe patient phenotypes and can offer important insight into fundamental disease mechanisms. We have performed a detailed study of tropomyosin (TPM1) E192K, a variant of uncertain significance associated with HCM. Molecular dynamics revealed that E192K results in a more flexible TPM1 molecule, which could affect its ability to regulate crossbridges. In vitro motility assays of regulated actin filaments containing TPM1 E192K showed an overall loss of Ca2+ sensitivity. To understand these effects, we used multiscale computational models that suggested a subtle phenotype in which E192K leads to an inability to completely inhibit actin-myosin crossbridge activity at low Ca2+. To assess the physiological impact of the mutation, we generated patient-derived engineered heart tissues expressing E192K. These tissues showed disease features similar to those of the patients, including cellular hypertrophy, hypercontractility, and diastolic dysfunction. We hypothesized that excess residual crossbridge activity could be triggering cellular hypertrophy, even if the overall Ca2+ sensitivity was reduced by E192K. To test this hypothesis, the cardiac myosin-specific inhibitor mavacamten was applied to patient-derived engineered heart tissues for 4 d followed by 24 h of washout. Chronic mavacamten treatment abolished contractile differences between control and TPM1 E192K engineered heart tissues and reversed hypertrophy in cardiomyocytes. These results suggest that the TPM1 E192K mutation triggers cardiomyocyte hypertrophy by permitting excess residual crossbridge activity. These studies also provide direct evidence that myosin inhibition by mavacamten can counteract the hypertrophic effects of mutant tropomyosin.
Collapse
Affiliation(s)
- Lorenzo R Sewanan
- Department of Biomedical Engineering, Yale University, New Haven, CT
| | - Jinkyu Park
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT.,Yale Stem Cell Center, Yale School of Medicine, New Haven, CT
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA
| | - Alice W Racca
- Department of Biological Sciences, University of Massachusetts, Lowell, MA
| | - Nikolaos Papoutsidakis
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT
| | - Jonas Schwan
- Department of Biomedical Engineering, Yale University, New Haven, CT
| | - Daniel L Jacoby
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT
| | - Jeffrey R Moore
- Department of Biological Sciences, University of Massachusetts, Lowell, MA
| | - William Lehman
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA
| | - Yibing Qyang
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT.,Yale Stem Cell Center, Yale School of Medicine, New Haven, CT.,Vascular Biology and Therapeutics Program, Yale University, New Haven, CT.,Department of Pathology, Yale University, New Haven, CT
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT.,Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT
| |
Collapse
|
10
|
Fan S, Gao L, Bell AC, Azure JA, Wang Y. Spontaneous myogenic fasciculation associated with the lengthening of cardiac muscle in response to static preloading. Sci Rep 2021; 11:14794. [PMID: 34285326 PMCID: PMC8292328 DOI: 10.1038/s41598-021-94335-w] [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: 02/19/2021] [Accepted: 07/09/2021] [Indexed: 02/06/2023] Open
Abstract
Force enhancement is one kind of myogenic spontaneous fasciculation in lengthening preload striated muscles. In cardiac muscle, the role of this biomechanical event is not well established. The physiological passive property is an essential part for maintaining normal diastole in the heart. In excessive preload heart, force enhancement relative erratic passive properties may cause muscle decompensating, implicate in the development of diastolic dysfunction. In this study, the force enhancement occurrence in mouse cardiac papillary muscle was evaluated by a microstepping stretch method. The intracellular Ca2+ redistribution during occurrence of force enhancement was monitored in real-time by a Flou-3 (2 mM) indicator. The force enhancement amplitude, the enhancement of the prolongation time, and the tension-time integral were analyzed by myography. The results indicated that the force enhancement occurred immediately after active stretching and was rapidly enhanced during sustained static stretch. The presence of the force and the increase in the amplitude synchronized with the acquisition and immediate transfer of Ca2+ to adjacent fibres. In highly preloaded fibres, the enhancement exceeded the maximum passive tension (from 4.49 ± 0.43 N/mm2 to 6.20 ± 0.51 N/mm2). The occurrence of force enhancement were unstable in each static stretch. The increased enhancement amplitude combined with the reduced prolongation time to induce a reduction in the tension-time integral. We concluded that intracellular Ca2+-synchronized force enhancement is one kind of interruption event in excessive preload cardiac muscle. During the cardiac muscle in its passive relaxation period, the occurrence of this interruption affected the rhythmic stability of the cardiac relaxation cycle.
Collapse
Affiliation(s)
- Shouyan Fan
- grid.443397.e0000 0004 0368 7493Laboratory of Extreme Environment Sports Medicine, Hainan Medical University, No. 3 Chengxi Xueyuan Road, Haikou, Hainan PFTZ 571199 China
| | - Lingfeng Gao
- grid.443397.e0000 0004 0368 7493Laboratory of Extreme Environment Sports Medicine, Hainan Medical University, No. 3 Chengxi Xueyuan Road, Haikou, Hainan PFTZ 571199 China
| | - Annie Christel Bell
- grid.443397.e0000 0004 0368 7493Laboratory of Extreme Environment Sports Medicine, Hainan Medical University, No. 3 Chengxi Xueyuan Road, Haikou, Hainan PFTZ 571199 China ,grid.443397.e0000 0004 0368 7493School of Emergency Trauma, Hainan Medical University, Haikou, Hainan PFTZ 571199 China
| | - Joseph Akparibila Azure
- grid.443397.e0000 0004 0368 7493Laboratory of Extreme Environment Sports Medicine, Hainan Medical University, No. 3 Chengxi Xueyuan Road, Haikou, Hainan PFTZ 571199 China ,grid.443397.e0000 0004 0368 7493School of Emergency Trauma, Hainan Medical University, Haikou, Hainan PFTZ 571199 China
| | - Yang Wang
- grid.443397.e0000 0004 0368 7493Laboratory of Extreme Environment Sports Medicine, Hainan Medical University, No. 3 Chengxi Xueyuan Road, Haikou, Hainan PFTZ 571199 China
| |
Collapse
|
11
|
Sewanan LR, Jacoby DL. Novel Myosin-Based Therapies in Hypertrophic Cardiomyopathy. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2021. [DOI: 10.1007/s11936-021-00921-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Creso JG, Campbell SG. Potential impacts of the cardiac troponin I mobile domain on myofilament activation and relaxation. J Mol Cell Cardiol 2021; 155:50-57. [PMID: 33647310 DOI: 10.1016/j.yjmcc.2021.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/13/2021] [Accepted: 02/22/2021] [Indexed: 10/22/2022]
Abstract
The cardiac thin filament is regulated in a Ca2+-dependent manner through conformational changes of troponin and tropomyosin (Tm). It has been generally understood that under conditions of low Ca2+ the inhibitory peptide domain (IP) of troponin I (TnI) binds to actin and holds Tm over the myosin binding sites on actin to prevent crossbridge formation. More recently, evidence that the C-terminal mobile domain (MD) of TnI also binds actin has made for a more complex scenario. This study uses a computational model to investigate the consequences of assuming that TnI regulates Tm movement via two actin-binding domains rather than one. First, a 16-state model of the cardiac thin filament regulatory unit was created with TnI-IP as the sole regulatory domain. Expansion of this to include TnI-MD formed a 24-state model. Comparison of these models showed that assumption of a second actin-binding site allows the individual domains to have a lower affinity for actin than would be required for IP acting alone. Indeed, setting actin affinities of the IP and MD to 25% of that assumed for the IP in the single-site model was sufficient to achieve precisely the same degree of Ca2+ regulation. We also tested the 24-state model's ability to represent steady-state experimental data in the case of disruption of either the IP or MD. We were able to capture qualitative changes in several properties that matched what was seen in the experimental data. Lastly, simulations were run to examine the effect of disruption of the IP or MD on twitch dynamics. Our results suggest that both domains are required to keep diastolic cross-bridge activity to a minimum and accelerate myofilament relaxation. Overall, our analyses support a paradigm in which two domains of TnI bind with moderate affinity to actin, working in tandem to complete Ca2+-dependent regulation of the thin filament.
Collapse
Affiliation(s)
- Jenette G Creso
- Department of Biomedical Engineering, Yale University, 55 Prospect St, New Haven, CT 06511, USA.
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, 55 Prospect St, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale School of Medicine, 333 Cedar St, New Haven, CT 06510, USA.
| |
Collapse
|
14
|
Abstract
The treatment of individual patients in cardiology practice increasingly relies on advanced imaging, genetic screening and devices. As the amount of imaging and other diagnostic data increases, paralleled by the greater capacity to personalize treatment, the difficulty of using the full array of measurements of a patient to determine an optimal treatment seems also to be paradoxically increasing. Computational models are progressively addressing this issue by providing a common framework for integrating multiple data sets from individual patients. These models, which are based on physiology and physics rather than on population statistics, enable computational simulations to reveal diagnostic information that would have otherwise remained concealed and to predict treatment outcomes for individual patients. The inherent need for patient-specific models in cardiology is clear and is driving the rapid development of tools and techniques for creating personalized methods to guide pharmaceutical therapy, deployment of devices and surgical interventions.
Collapse
|
15
|
Aboelkassem Y, Powers JD, McCabe KJ, McCulloch AD. Multiscale Models of Cardiac Muscle Biophysics and Tissue Remodeling in Hypertrophic Cardiomyopathies. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019; 11:35-44. [PMID: 31886450 DOI: 10.1016/j.cobme.2019.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Myocardial hypertrophy is the result of sustained perturbations to the mechanical and/or neurohormonal homeostasis of cardiac cells and is driven by integrated, multiscale biophysical and biochemical processes that are currently not well defined. In this brief review, we highlight recent computational and experimental models of cardiac hypertrophy that span mechanisms from the molecular level to the tissue level. Specifically, we focus on: (i) molecular-level models of the structural dynamics of sarcomere proteins in hypertrophic hearts, (ii) cellular-level models of excitation-contraction coupling and mechanosensitive signaling in disease-state myocytes, and (iii) organ-level models of myocardial growth kinematics and predictors thereof. Finally, we discuss how spanning these scales and combining multiple experimental/computational models will provide new information about the processes governing hypertrophy and potential methods to prevent or reverse them.
Collapse
Affiliation(s)
- Yasser Aboelkassem
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Joseph D Powers
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Kimberly J McCabe
- Department of Computational Physiology, Simula Research Laboratory, Lysaker, Norway
| | - Andrew D McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
16
|
Bowman JD, Lindert S. Computational Studies of Cardiac and Skeletal Troponin. Front Mol Biosci 2019; 6:68. [PMID: 31448287 PMCID: PMC6696891 DOI: 10.3389/fmolb.2019.00068] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022] Open
Abstract
Troponin is a key regulatory protein in muscle contraction, consisting of three subunits troponin C (TnC), troponin I (TnI), and troponin T (TnT). Calcium association to TnC initiates contraction by causing a series of dynamic and conformational changes that allow the switch peptide of TnI to bind and subsequently cross bridges to form between the thin and thick filament of the sarcomere. Owing to its pivotal role in contraction regulation, troponin has been the focus of numerous computational studies over the last decade. These studies elegantly supplemented a large volume of experimental work and focused on the structure, dynamics and function of the whole troponin complex, individual subunits, and even on segments of the thin filament. Molecular dynamics, Brownian dynamics, and free energy simulations have been used to elucidate the conformational dynamics and underlying free energy landscape of troponin, calcium, and switch peptide binding, as well as the effect of disease mutations, small molecules and post-translational modifications such as phosphorylation. Frequently, simulations have been used to confirm or explain experimental observations. Computer-aided drug discovery tools have been employed to identify novel potential calcium sensitizing agents binding to the TnC-TnI interface. Finally, Markov modeling has contributed to simulating contraction within the sarcomere on the mesoscale. Here we are reviewing and classifying the existing computational work on troponin and its subunits, outline current gaps in simulations elucidating troponin's role in contraction and suggest potential future developments in the field.
Collapse
Affiliation(s)
- Jacob D Bowman
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, United States
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, United States
| |
Collapse
|
17
|
Aboelkassem Y, McCabe KJ, Huber GA, Regnier M, McCammon JA, McCulloch AD. A Stochastic Multiscale Model of Cardiac Thin Filament Activation Using Brownian-Langevin Dynamics. Biophys J 2019; 117:2255-2272. [PMID: 31547973 DOI: 10.1016/j.bpj.2019.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 07/31/2019] [Accepted: 08/02/2019] [Indexed: 11/16/2022] Open
Abstract
We use Brownian-Langevin dynamics principles to derive a coarse-graining multiscale myofilament model that can describe the thin-filament activation process during contraction. The model links atomistic molecular simulations of protein-protein interactions in the thin-filament regulatory unit to sarcomere-level activation dynamics. We first calculate the molecular interaction energy between tropomyosin and actin surface using Brownian dynamics simulations. This energy profile is then generalized to account for the observed tropomyosin transitions between its regulatory stable states. The generalized energy landscape then served as a basis for developing a filament-scale model using Langevin dynamics. This integrated analysis, spanning molecular to thin-filament scales, is capable of tracking the events of the tropomyosin conformational changes as it moves over the actin surface. The tropomyosin coil with flexible overlap regions between adjacent tropomyosins is represented in the model as a system of coupled stochastic ordinary differential equations. The proposed multiscale approach provides a more detailed molecular connection between tropomyosin dynamics, the trompomyosin-actin interaction-energy landscape, and the generated force by the sarcomere.
Collapse
Affiliation(s)
- Yasser Aboelkassem
- Department of Bioengineering, University of California San Diego, La Jolla, California.
| | - Kimberly J McCabe
- Department of Bioengineering, University of California San Diego, La Jolla, California
| | - Gary A Huber
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - J Andrew McCammon
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Andrew D McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, California
| |
Collapse
|
18
|
Affiliation(s)
- Stuart G Campbell
- From the Department of Biomedical Engineering (S.G.C.), Yale University, New Haven, CT.,Department of Cellular and Molecular Physiology (S.G.C.), Yale School of Medicine, New Haven, CT
| | - Yibing Qyang
- From the Department of Biomedical Engineering (S.G.C.), Yale University, New Haven, CT.,Yale Stem Cell Center (Y.Q.), Yale University, New Haven, CT.,Vascular Biology and Therapeutics Program (Y.Q.), Yale University, New Haven, CT.,Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine (Y.Q.), Yale School of Medicine, New Haven, CT
| | - J Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT (J.T.H.).,Department of Cardiology, UConn Health, Farmington, CT (J.T.H.)
| |
Collapse
|
19
|
Williams CD, Holt NC. Spatial Scale and Structural Heterogeneity in Skeletal Muscle Performance. Integr Comp Biol 2018; 58:163-173. [DOI: 10.1093/icb/icy057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- C D Williams
- Allen Institute for Cell Science, 615 Westlake Ave N, Seattle, WA 98109, USA
| | - N C Holt
- Department of Biology, Northern Arizona University, S. San Francisco Street, Flagstaff, AZ 86011, USA
| |
Collapse
|
20
|
Farman GP, Rynkiewicz MJ, Orzechowski M, Lehman W, Moore JR. HCM and DCM cardiomyopathy-linked α-tropomyosin mutations influence off-state stability and crossbridge interaction on thin filaments. Arch Biochem Biophys 2018; 647:84-92. [PMID: 29626422 DOI: 10.1016/j.abb.2018.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 12/19/2022]
Abstract
Calcium regulation of cardiac muscle contraction is controlled by the thin-filament proteins troponin and tropomyosin bound to actin. In the absence of calcium, troponin-tropomyosin inhibits myosin-interactions on actin and induces muscle relaxation, whereas the addition of calcium relieves the inhibitory constraint to initiate contraction. Many mutations in thin filament proteins linked to cardiomyopathy appear to disrupt this regulatory switching. Here, we tested perturbations caused by mutant tropomyosins (E40K, DCM; and E62Q, HCM) on intra-filament interactions affecting acto-myosin interactions including those induced further by myosin association. Comparison of wild-type and mutant human α-tropomyosin (Tpm1.1) behavior was carried out using in vitro motility assays and molecular dynamics simulations. Our results show that E62Q tropomyosin destabilizes thin filament off-state function by increasing calcium-sensitivity, but without apparent affect on global tropomyosin structure by modifying coiled-coil rigidity. In contrast, the E40K mutant tropomyosin appears to stabilize the off-state, demonstrates increased tropomyosin flexibility, while also decreasing calcium-sensitivity. In addition, the E40K mutation reduces thin filament velocity at low myosin concentration while the E62Q mutant tropomyosin increases velocity. Corresponding molecular dynamics simulations indicate specific residue interactions that are likely to redefine underlying molecular regulatory mechanisms, which we propose explain the altered contractility evoked by the disease-causing mutations.
Collapse
Affiliation(s)
- Gerrie P Farman
- Department of Biological Sciences, University of Massachusetts-Lowell, One University Avenue, Lowell, MA 01854, USA; Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| | - Michael J Rynkiewicz
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| | - Marek Orzechowski
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| | - William Lehman
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| | - Jeffrey R Moore
- Department of Biological Sciences, University of Massachusetts-Lowell, One University Avenue, Lowell, MA 01854, USA.
| |
Collapse
|
21
|
Budna J, Bryja A, Celichowski P, Kahan R, Kranc W, Ciesiółka S, Rybska M, Borys S, Jeseta M, Bukowska D, Antosik P, Brüssow KP, Bruska M, Nowicki M, Zabel M, Kempisty B. Genes of cellular components of morphogenesis in porcine oocytes before and after IVM. Reproduction 2017; 154:535-545. [PMID: 28733345 DOI: 10.1530/rep-17-0367] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 07/04/2017] [Accepted: 07/21/2017] [Indexed: 12/13/2022]
Abstract
Proper oocyte maturation in mammals produces an oocyte capable of monospermic fertilization and embryo preimplantation. The cumulus-oocyte complexes (COCs), surrounding an oocyte, play a significant role in oocyte maturation. During this process, when the COCs undergo cumulus expansion wherein tightly compact cumulus cells (CCs) form a dispersed structure, permanent biochemical and molecular modifications occur in the maturing oocytes, indicating that the gene expression between immature and mature oocytes differs significantly. This study focuses on the genes responsible for the cellular components of morphogenesis within the developing oocyte. Brilliant cresyl blue (BCB) was used to determine the developmental capability of porcine oocytes. The immature oocytes (GV stage) were compared with matured oocytes (MII stage), using microarray and qRT-PCR analysis to track changes in the genetic expression profile of transcriptome genes. The data showed substantial upregulation of genes influencing oocyte's morphology, cellular migration and adhesion, intracellular communication, as well as plasticity of nervous system. Conversely, downregulation involved genes related to microtubule reorganization, regulation of adhesion, proliferation, migration and cell differentiation processes in oocytes. This suggests that most genes recruited in morphogenesis in porcine oocyte in vitro, may have cellular maturational capability, since they have a higher level of expression before the oocyte's matured form. It shows the process of oocyte maturation and developmental capacity is orchestrated by significant cellular modifications during morphogenesis.
Collapse
Affiliation(s)
- Joanna Budna
- Department of Histology and EmbryologyPoznan University of Medical Sciences, Poznan, Poland
| | - Artur Bryja
- Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland
| | - Piotr Celichowski
- Department of Histology and EmbryologyPoznan University of Medical Sciences, Poznan, Poland
| | - Rotem Kahan
- Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland
| | - Wiesława Kranc
- Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland
| | - Sylwia Ciesiółka
- Department of Histology and EmbryologyPoznan University of Medical Sciences, Poznan, Poland
| | - Marta Rybska
- Institute of Veterinary SciencesPoznan University of Life Sciences, Poznan, Poland
| | - Sylwia Borys
- Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland
| | - Michal Jeseta
- Department of Obstetrics and GynecologyUniversity Hospital and Masaryk University, Brno, Czech Republic
| | - Dorota Bukowska
- Institute of Veterinary SciencesPoznan University of Life Sciences, Poznan, Poland
| | - Paweł Antosik
- Institute of Veterinary SciencesPoznan University of Life Sciences, Poznan, Poland
| | - Klaus P Brüssow
- Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland
| | - Małgorzata Bruska
- Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland
| | - Michał Nowicki
- Department of Histology and EmbryologyPoznan University of Medical Sciences, Poznan, Poland
| | - Maciej Zabel
- Department of Histology and EmbryologyPoznan University of Medical Sciences, Poznan, Poland.,Department of Histology and EmbryologyWroclaw Medical University, Wroclaw, Poland
| | - Bartosz Kempisty
- Department of Histology and EmbryologyPoznan University of Medical Sciences, Poznan, Poland .,Department of AnatomyPoznan University of Medical Sciences, Poznan, Poland.,Department of Obstetrics and GynecologyUniversity Hospital and Masaryk University, Brno, Czech Republic
| |
Collapse
|
22
|
McConnell M, Tal Grinspan L, Williams MR, Lynn ML, Schwartz BA, Fass OZ, Schwartz SD, Tardiff JC. Clinically Divergent Mutation Effects on the Structure and Function of the Human Cardiac Tropomyosin Overlap. Biochemistry 2017; 56:3403-3413. [PMID: 28603979 DOI: 10.1021/acs.biochem.7b00266] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The progression of genetically inherited cardiomyopathies from an altered protein structure to clinical presentation of disease is not well understood. One of the main roadblocks to mechanistic insight remains a lack of high-resolution structural information about multiprotein complexes within the cardiac sarcomere. One example is the tropomyosin (Tm) overlap region of the thin filament that is crucial for the function of the cardiac sarcomere. To address this central question, we devised coupled experimental and computational modalities to characterize the baseline function and structure of the Tm overlap, as well as the effects of mutations causing divergent patterns of ventricular remodeling on both structure and function. Because the Tm overlap contributes to the cooperativity of myofilament activation, we hypothesized that mutations that enhance the interactions between overlap proteins result in more cooperativity, and conversely, those that weaken interaction between these elements lower cooperativity. Our results suggest that the Tm overlap region is affected differentially by dilated cardiomyopathy-associated Tm D230N and hypertrophic cardiomyopathy-associated human cardiac troponin T (cTnT) R92L. The Tm D230N mutation compacts the Tm overlap region, increasing the cooperativity of the Tm filament, contributing to a dilated cardiomyopathy phenotype. The cTnT R92L mutation causes weakened interactions closer to the N-terminal end of the overlap, resulting in decreased cooperativity. These studies demonstrate that mutations with differential phenotypes exert opposite effects on the Tm-Tn overlap, and that these effects can be directly correlated to a molecular level understanding of the structure and dynamics of the component proteins.
Collapse
Affiliation(s)
- Mark McConnell
- Department of Biomedical Engineering, University of Arizona , Tucson, Arizona 85721, United States
| | - Lauren Tal Grinspan
- Department of Medicine, Columbia University Medical Center , New York, New York 10032, United States
| | - Michael R Williams
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Melissa L Lynn
- Department of Physiological Sciences, University of Arizona , Tucson, Arizona 85724, United States
| | - Benjamin A Schwartz
- Graduate Interdisciplinary Program in Neuroscience, University of Arizona , Tucson, Arizona 85721, United States
| | - Ofer Z Fass
- Department of Physiological Sciences, University of Arizona , Tucson, Arizona 85724, United States
| | - Steven D Schwartz
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States
| | - Jil C Tardiff
- Department of Biomedical Engineering, University of Arizona , Tucson, Arizona 85721, United States.,Department of Physiological Sciences, University of Arizona , Tucson, Arizona 85724, United States.,Department of Medicine, University of Arizona , Tucson, Arizona 85724, United States
| |
Collapse
|
23
|
Xin X, Wang T, Liu X, Sui G, Jin C, Yue Y, Yang S, Guo H. A yeast two-hybrid assay reveals CMYA1 interacting proteins. C R Biol 2017; 340:314-323. [DOI: 10.1016/j.crvi.2017.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 05/19/2017] [Accepted: 06/13/2017] [Indexed: 10/19/2022]
|
24
|
Dewan S, McCabe KJ, Regnier M, McCulloch AD. Insights and Challenges of Multi-Scale Modeling of Sarcomere Mechanics in cTn and Tm DCM Mutants-Genotype to Cellular Phenotype. Front Physiol 2017; 8:151. [PMID: 28352236 PMCID: PMC5348544 DOI: 10.3389/fphys.2017.00151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/24/2017] [Indexed: 01/18/2023] Open
Abstract
Dilated Cardiomyopathy (DCM) is a leading cause of sudden cardiac death characterized by impaired pump function and dilatation of cardiac ventricles. In this review we discuss various in silico approaches to elucidating the mechanisms of genetic mutations leading to DCM. The approaches covered in this review focus on bridging the spatial and temporal gaps that exist between molecular and cellular processes. Mutations in sarcomeric regulatory thin filament proteins such as the troponin complex (cTn) and Tropomyosin (Tm) have been associated with DCM. Despite the experimentally-observed myofilament measures of contractility in the case of these mutations, the mechanisms by which the underlying molecular changes and protein interactions scale up to organ failure by these mutations remains elusive. The review highlights multi-scale modeling approaches and their applicability to study the effects of sarcomeric gene mutations in-silico. We discuss some of the insights that can be gained from computational models of cardiac biomechanics when scaling from molecular states to cellular level.
Collapse
Affiliation(s)
- Sukriti Dewan
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kimberly J McCabe
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Michael Regnier
- Departments of Bioengineering and Medicine, University of Washington Seattle, WA, USA
| | - Andrew D McCulloch
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|