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Morales PN, Coons AN, Koopman AJ, Patel S, Chase PB, Parvatiyar MS, Pinto JR. Post-translational modifications of vertebrate striated muscle myosin heavy chains. Cytoskeleton (Hoboken) 2024. [PMID: 38587113 DOI: 10.1002/cm.21857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/06/2024] [Accepted: 03/25/2024] [Indexed: 04/09/2024]
Abstract
Post-translational modifications (PTMs) play a crucial role in regulating the function of many sarcomeric proteins, including myosin. Myosins comprise a family of motor proteins that play fundamental roles in cell motility in general and muscle contraction in particular. A myosin molecule consists of two myosin heavy chains (MyHCs) and two pairs of myosin light chains (MLCs); two MLCs are associated with the neck region of each MyHC's N-terminal head domain, while the two MyHC C-terminal tails form a coiled-coil that polymerizes with other MyHCs to form the thick filament backbone. Myosin undergoes extensive PTMs, and dysregulation of these PTMs may lead to abnormal muscle function and contribute to the development of myopathies and cardiovascular disorders. Recent studies have uncovered the significance of PTMs in regulating MyHC function and showed how these PTMs may provide additional modulation of contractile processes. Here, we discuss MyHC PTMs that have been biochemically and/or functionally studied in mammals' and rodents' striated muscle. We have identified hotspots or specific regions in three isoforms of myosin (MYH2, MYH6, and MYH7) where the prevalence of PTMs is more frequent and could potentially play a significant role in fine-tuning the activity of these proteins.
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Affiliation(s)
- Paula Nieto Morales
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
| | - Arianna N Coons
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Amelia J Koopman
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Sonu Patel
- Department of Health, Nutrition and Food Sciences, Florida State University, Tallahassee, Florida, USA
| | - P Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Michelle S Parvatiyar
- Department of Health, Nutrition and Food Sciences, Florida State University, Tallahassee, Florida, USA
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
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Saad NS, Mashali MA, Repas SJ, Janssen PML. Altering Calcium Sensitivity in Heart Failure: A Crossroads of Disease Etiology and Therapeutic Innovation. Int J Mol Sci 2023; 24:17577. [PMID: 38139404 PMCID: PMC10744146 DOI: 10.3390/ijms242417577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
Heart failure (HF) presents a significant clinical challenge, with current treatments mainly easing symptoms without stopping disease progression. The targeting of calcium (Ca2+) regulation is emerging as a key area for innovative HF treatments that could significantly alter disease outcomes and enhance cardiac function. In this review, we aim to explore the implications of altered Ca2+ sensitivity, a key determinant of cardiac muscle force, in HF, including its roles during systole and diastole and its association with different HF types-HF with preserved and reduced ejection fraction (HFpEF and HFrEF, respectively). We further highlight the role of the two rate constants kon (Ca2+ binding to Troponin C) and koff (its dissociation) to fully comprehend how changes in Ca2+ sensitivity impact heart function. Additionally, we examine how increased Ca2+ sensitivity, while boosting systolic function, also presents diastolic risks, potentially leading to arrhythmias and sudden cardiac death. This suggests that strategies aimed at moderating myofilament Ca2+ sensitivity could revolutionize anti-arrhythmic approaches, reshaping the HF treatment landscape. In conclusion, we emphasize the need for precision in therapeutic approaches targeting Ca2+ sensitivity and call for comprehensive research into the complex interactions between Ca2+ regulation, myofilament sensitivity, and their clinical manifestations in HF.
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Affiliation(s)
- Nancy S. Saad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo 11795, Egypt
| | - Mohammed A. Mashali
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Surgery, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22514, Egypt
| | - Steven J. Repas
- Department of Emergency Medicine, Wright State University Boonshoft School of Medicine, Dayton, OH 45324, USA;
| | - Paul M. L. Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Hilderink S, Schuldt M, Goebel M, Jansen VJ, Manders E, Moorman S, Dorsch LM, van Steenbeek FG, van der Velden J, Kuster DWD. Characterization of heterozygous and homozygous mouse models with the most common hypertrophic cardiomyopathy mutation MYBPC3 c.2373InsG in the Netherlands. J Mol Cell Cardiol 2023; 185:65-76. [PMID: 37844837 DOI: 10.1016/j.yjmcc.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 09/25/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in the cardiac myosin binding protein-C (cMyBP-C) encoding gene MYBPC3. In the Netherlands, approximately 25% of patients carry the MYBPC3c.2373InsG founder mutation. Most patients are heterozygous (MYBPC3+/InsG) and have highly variable phenotypic expression, whereas homozygous (MYBPC3InsG/InsG) patients have severe HCM at a young age. To improve understanding of disease progression and genotype-phenotype relationship based on the hallmarks of human HCM, we characterized mice with CRISPR/Cas9-induced heterozygous and homozygous mutations. At 18-28 weeks of age, we assessed the cardiac phenotype of Mybpc3+/InsG and Mybpc3InsG/InsG mice with echocardiography, and performed histological analyses. Cytoskeletal proteins and cardiomyocyte contractility of 3-4 week old and 18-28 week old Mybpc3c.2373InsG mice were compared to wild-type (WT) mice. Expectedly, knock-in of Mybpc3c.2373InsG resulted in the absence of cMyBP-C and our 18-28 week old homozygous Mybpc3c.2373InsG model developed cardiac hypertrophy and severe left ventricular systolic and diastolic dysfunction, whereas HCM was not evident in Mybpc3+/InsG mice. Mybpc3InsG/InsG cardiomyocytes also presented with slowed contraction-relaxation kinetics, to a greater extent in 18-28 week old mice, partially due to increased levels of detyrosinated tubulin and desmin, and reduced cardiac troponin I (cTnI) phosphorylation. Impaired cardiomyocyte contraction-relaxation kinetics were successfully normalized in 18-28 week old Mybpc3InsG/InsG cardiomyocytes by combining detyrosination inhibitor parthenolide and β-adrenergic receptor agonist isoproterenol. Both the 3-4 week old and 18-28 week old Mybpc3InsG/InsG models recapitulate HCM, with a severe phenotype present in the 18-28 week old model.
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Affiliation(s)
- Sarah Hilderink
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Maike Schuldt
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Max Goebel
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Valentijn J Jansen
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Emmy Manders
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands
| | - Stan Moorman
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Larissa M Dorsch
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Frank G van Steenbeek
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands; Department of Cardiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht University, 3508 GA Utrecht, the Netherlands; Regenerative Medicine Center Utrecht, University Medical Center Utrecht, Utrecht University, 3584 CT Utrecht, the Netherlands
| | - Jolanda van der Velden
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Diederik W D Kuster
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands.
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Cebro-Márquez M, Rodríguez-Mañero M, Serrano-Cruz V, Vilar-Sánchez ME, González-Melchor L, García-Seara J, Martínez-Sande JL, Aragón-Herrera A, Martínez-Monzonís MA, González-Juanatey JR, Lage R, Moscoso I. Plasma miR-486-5p Expression Is Upregulated in Atrial Fibrillation Patients with Broader Low-Voltage Areas. Int J Mol Sci 2023; 24:15248. [PMID: 37894937 PMCID: PMC10607367 DOI: 10.3390/ijms242015248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
Atrial fibrillation (AF) is the most common arrhythmia worldwide, affecting 1% of the population over 60 years old. The incidence and prevalence of AF are increasing globally, representing a relevant health problem, suggesting that more advanced strategies for predicting risk stage are highly needed. miRNAs mediate several processes involved in AF. Our aim was to identify miRNAs with a prognostic value as biomarkers in patients referred for AF ablation and its association with LVA extent, based on low-voltage area (LVA) maps. In this study, we recruited 44 AF patients referred for catheter ablation. We measured the expression of 84 miRNAs in plasma from peripheral blood in 3 different groups based on LVA extent. Expression analysis showed that miR-486-5p was significantly increased in patients with broader LVA (4-fold, p = 0.0002; 5-fold, p = 0.0001). Receiver operating characteristic curve analysis showed that miR-486-5p expression could predict atrium LVA (AUC, 0.8958; p = 0.0015). Also, miR-486-5p plasma levels were associated with AF-type (AUC, 0.7137; p = 0.0453). In addition, miR-486-5p expression was positively correlated with LVA percentage, left atrial (LA) area, and LA volume (r = 0.322, p = 0.037; r = 0.372, p = 0.015; r = 0.319, p = 0.045, respectively). These findings suggest that miR-486-5p expression might have prognostic significance in LVA extent in patients with AF.
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Affiliation(s)
- María Cebro-Márquez
- Cardiology Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; (M.C.-M.); (V.S.-C.); (M.E.V.-S.)
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Moisés Rodríguez-Mañero
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Valentina Serrano-Cruz
- Cardiology Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; (M.C.-M.); (V.S.-C.); (M.E.V.-S.)
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
| | - Marta E. Vilar-Sánchez
- Cardiology Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; (M.C.-M.); (V.S.-C.); (M.E.V.-S.)
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
| | - Laila González-Melchor
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
| | - Javier García-Seara
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - José Luis Martínez-Sande
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Alana Aragón-Herrera
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Cellular and Molecular Cardiology Research Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain
| | - María Amparo Martínez-Monzonís
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - José Ramón González-Juanatey
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Ricardo Lage
- Cardiology Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; (M.C.-M.); (V.S.-C.); (M.E.V.-S.)
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Isabel Moscoso
- Cardiology Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; (M.C.-M.); (V.S.-C.); (M.E.V.-S.)
- Department of Cardiology and Coronary Unit, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain; (M.R.-M.); (L.G.-M.); (J.G.-S.); (J.L.M.-S.); (A.A.-H.); (M.A.M.-M.); (J.R.G.-J.)
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
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Lynn ML, Jimenez J, Castillo RL, Klass MM, Vasquez C, Baldo A, Gibson C, Murphy AM, Tardiff JC. The HCM - Linked Mutation Arg92Leu in TNNT2 Allosterically Alters the cTnC - cTnI Interface and Disrupts the PKA-mediated Regulation of Myofilament Relaxation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.549569. [PMID: 37503299 PMCID: PMC10370115 DOI: 10.1101/2023.07.18.549569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Background Impaired left ventricular relaxation, high filling pressures, and dysregulation of Ca 2+ homeostasis are common findings contributing to diastolic dysfunction in hypertrophic cardiomyopathy (HCM). Studies have shown that impaired relaxation is an early observation in the sarcomere-gene-positive preclinical HCM cohort which suggests potential involvement of myofilament regulators of relaxation. Yet, a molecular level understanding of mechanism(s) at the level of the myofilament is lacking. We hypothesized that mutation-specific, allosterically mediated, changes to the cardiac troponin C-cardiac troponin I (cTnC-cTnI) interface can account for the development of early-onset diastolic dysfunction via decreased PKA accessibility to cTnI. Methods HCM mutations R92L-cTnT (Arg92Leu) and Δ160E-cTnT (Glu160 deletion) were studied in vivo , in vitro, and in silico via 2D echocardiography, western blotting, ex vivo hemodynamics, stopped-flow kinetics, time resolved fluorescence resonance energy transfer (TR-FRET), and molecular dynamics simulations. Results The HCM-causative mutations R92L-cTnT and Δ160E-cTnT result in different time-of-onset of diastolic dysfunction. R92L-cTnT demonstrated early-onset diastolic dysfunction accompanied by a localized decrease in phosphorylation of cTnI. Constitutive phosphorylation of cTnI (cTnI-D 23 D 24 ) was sufficient to recover diastolic function to Non-Tg levels only for R92L-cTnT. Mutation-specific changes in Ca 2+ dissociation rates associated with R92L-cTnT reconstituted with cTnI-D 23 D 24 led us to investigate potential involvement of structural changes in the cTnC-cTnI interface as an explanation for these observations. We probed the interface via TR-FRET revealing a repositioning of the N-terminus of cTnI, closer to cTnC, and concomitant decreases in distance distributions at sites flanking the PKA consensus sequence. Implementing TR-FRET distances as constraints into our atomistic model identified additional electrostatic interactions at the consensus sequence. Conclusion These data indicate that the early diastolic dysfunction observed in a subset of HCM is likely attributable to structural changes at the cTnC-cTnI interface that impair accessibility of PKA thereby blunting β-adrenergic responsiveness and identifying a potential molecular target for therapeutic intervention.
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Chakraborty AD, Kooiker K, Kobak KA, Cheng Y, Lee CF, Razumova M, Granzier H H, Regnier M, Rabinovitch PS, Moussavi-Harami F, Chiao YA. Late-life Rapamycin Treatment Enhances Cardiomyocyte Relaxation Kinetics and Reduces Myocardial Stiffness. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.544619. [PMID: 37398078 PMCID: PMC10312630 DOI: 10.1101/2023.06.12.544619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Diastolic dysfunction is a key feature of the aging heart. We have shown that late-life treatment with mTOR inhibitor, rapamycin, reverses age-related diastolic dysfunction in mice but the molecular mechanisms of the reversal remain unclear. To dissect the mechanisms by which rapamycin improves diastolic function in old mice, we examined the effects of rapamycin treatment at the levels of single cardiomyocyte, myofibril and multicellular cardiac muscle. Compared to young cardiomyocytes, isolated cardiomyocytes from old control mice exhibited prolonged time to 90% relaxation (RT 90 ) and time to 90% Ca 2+ transient decay (DT 90 ), indicating slower relaxation kinetics and calcium reuptake with age. Late-life rapamycin treatment for 10 weeks completely normalized RT 90 and partially normalized DT 90 , suggesting improved Ca 2+ handling contributes partially to the rapamycin-induced improved cardiomyocyte relaxation. In addition, rapamycin treatment in old mice enhanced the kinetics of sarcomere shortening and Ca 2+ transient increase in old control cardiomyocytes. Myofibrils from old rapamycin-treated mice displayed increased rate of the fast, exponential decay phase of relaxation compared to old controls. The improved myofibrillar kinetics were accompanied by an increase in MyBP-C phosphorylation at S282 following rapamycin treatment. We also showed that late-life rapamycin treatment normalized the age-related increase in passive stiffness of demembranated cardiac trabeculae through a mechanism independent of titin isoform shift. In summary, our results showed that rapamycin treatment normalizes the age-related impairments in cardiomyocyte relaxation, which works conjointly with reduced myocardial stiffness to reverse age-related diastolic dysfunction.
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Feng HZ, Huang X, Jin JP. N-terminal truncated cardiac troponin I enhances Frank-Starling response by increasing myofilament sensitivity to resting tension. J Gen Physiol 2023; 155:e202012821. [PMID: 36880803 PMCID: PMC10005897 DOI: 10.1085/jgp.202012821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/09/2022] [Accepted: 12/29/2022] [Indexed: 03/08/2023] Open
Abstract
Cardiac troponin I (cTnI) of higher vertebrates has evolved with an N-terminal extension, of which deletion via restrictive proteolysis occurs as a compensatory adaptation in chronic heart failure to increase ventricular relaxation and stroke volume. Here, we demonstrate in a transgenic mouse model expressing solely N-terminal truncated cTnI (cTnI-ND) in the heart with deletion of the endogenous cTnI gene. Functional studies using ex vivo working hearts showed an extended Frank-Starling response to preload with reduced left ventricular end diastolic pressure. The enhanced Frank-Starling response effectively increases systolic ventricular pressure development and stroke volume. A novel finding is that cTnI-ND increases left ventricular relaxation velocity and stroke volume without increasing the end diastolic volume. Consistently, the optimal resting sarcomere length (SL) for maximum force development in cTnI-ND cardiac muscle was not different from wild-type (WT) control. Despite the removal of the protein kinase A (PKA) phosphorylation sites in cTnI, β-adrenergic stimulation remains effective on augmenting the enhanced Frank-Starling response of cTnI-ND hearts. Force-pCa relationship studies using skinned preparations found that while cTnI-ND cardiac muscle shows a resting SL-resting tension relationship similar to WT control, cTnI-ND significantly increases myofibril Ca2+ sensitivity to resting tension. The results demonstrate that restrictive N-terminal deletion of cTnI enhances Frank-Starling response by increasing myofilament sensitivity to resting tension rather than directly depending on SL. This novel function of cTnI regulation suggests a myofilament approach to utilizing Frank-Starling mechanism for the treatment of heart failure, especially diastolic failure where ventricular filling is limited.
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Affiliation(s)
- Han-Zhong Feng
- Department of Physiology and Biophysics, University of Illinois at Chicago School of Medicine, Chicago, IL, USA
| | - Xupei Huang
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Jian-Ping Jin
- Department of Physiology and Biophysics, University of Illinois at Chicago School of Medicine, Chicago, IL, USA
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8
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Salhi HE, Shettigar V, Salyer L, Sturgill S, Brundage EA, Robinett J, Xu Z, Abay E, Lowe J, Janssen PML, Rafael-Fortney JA, Weisleder N, Ziolo MT, Biesiadecki BJ. The lack of Troponin I Ser-23/24 phosphorylation is detrimental to in vivo cardiac function and exacerbates cardiac disease. J Mol Cell Cardiol 2023; 176:84-96. [PMID: 36724829 PMCID: PMC10074981 DOI: 10.1016/j.yjmcc.2023.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 01/11/2023] [Accepted: 01/24/2023] [Indexed: 01/30/2023]
Abstract
Troponin I (TnI) is a key regulator of cardiac contraction and relaxation with TnI Ser-23/24 phosphorylation serving as a myofilament mechanism to modulate cardiac function. Basal cardiac TnI Ser-23/24 phosphorylation is high such that both increased and decreased TnI phosphorylation may modulate cardiac function. While the effects of increasing TnI Ser-23/24 phosphorylation on heart function are well established, the effects of decreasing TnI Ser-23/24 phosphorylation are not clear. To understand the in vivo role of decreased TnI Ser-23/24 phosphorylation, mice expressing TnI with Ser-23/24 mutated to alanine (TnI S23/24A) that lack the ability to be phosphorylated at these residues were subjected to echocardiography and pressure-volume hemodynamic measurements in the absence or presence of physiological (pacing increasing heart rate or adrenergic stimulation) or pathological (transverse aortic constriction (TAC)) stress. In the absence of pathological stress, the lack of TnI Ser-23/24 phosphorylation impaired systolic and diastolic function. TnI S23/24A mice also had an impaired systolic and diastolic response upon stimulation increased heart rate and an impaired adrenergic response upon dobutamine infusion. Following pathological cardiac stress induced by TAC, TnI S23/24A mice had a greater increase in ventricular mass, worse diastolic function, and impaired systolic and diastolic function upon increasing heart rate. These findings demonstrate that mice lacking the ability to phosphorylate TnI at Ser-23/24 have impaired in vivo systolic and diastolic cardiac function, a blunted cardiac reserve and a worse response to pathological stress supporting decreased TnI Ser23/24 phosphorylation is a modulator of these processes in vivo.
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Affiliation(s)
- Hussam E Salhi
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Vikram Shettigar
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Lorien Salyer
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Sarah Sturgill
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Joel Robinett
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Zhaobin Xu
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Eaman Abay
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Jeovanna Lowe
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Jill A Rafael-Fortney
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Noah Weisleder
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Mark T Ziolo
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America.
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9
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Subramanian H, Nikolaev VO. A-Kinase Anchoring Proteins in Cardiac Myocytes and Their Roles in Regulating Calcium Cycling. Cells 2023; 12:cells12030436. [PMID: 36766777 PMCID: PMC9913689 DOI: 10.3390/cells12030436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
The rate of calcium cycling and calcium transient amplitude are critical determinants for the efficient contraction and relaxation of the heart. Calcium-handling proteins in the cardiac myocyte are altered in heart failure, and restoring the proper function of those proteins is an effective potential therapeutic strategy. The calcium-handling proteins or their regulators are phosphorylated by a cAMP-dependent kinase (PKA), and thereby their activity is regulated. A-Kinase Anchoring Proteins (AKAPs) play a seminal role in orchestrating PKA and cAMP regulators in calcium handling and contractile machinery. This cAMP/PKA orchestration is crucial for the increased force and rate of contraction and relaxation of the heart in response to fight-or-flight. Knockout models and the few available preclinical models proved that the efficient targeting of AKAPs offers potential therapies tailor-made for improving defective calcium cycling. In this review, we highlight important studies that identified AKAPs and their regulatory roles in cardiac myocyte calcium cycling in health and disease.
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Affiliation(s)
- Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck
- Correspondence: (H.S.); (V.O.N.); Tel.: +49(0)40-7410-57383 (V.O.N.)
| | - Viacheslav O. Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck
- Correspondence: (H.S.); (V.O.N.); Tel.: +49(0)40-7410-57383 (V.O.N.)
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10
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Sevrieva IR, Ponnam S, Yan Z, Irving M, Kampourakis T, Sun YB. Phosphorylation-dependent interactions of myosin-binding protein C and troponin coordinate the myofilament response to protein kinase A. J Biol Chem 2023; 299:102767. [PMID: 36470422 PMCID: PMC9826837 DOI: 10.1016/j.jbc.2022.102767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
PKA-mediated phosphorylation of sarcomeric proteins enhances heart muscle performance in response to β-adrenergic stimulation and is associated with accelerated relaxation and increased cardiac output for a given preload. At the cellular level, the latter translates to a greater dependence of Ca2+ sensitivity and maximum force on sarcomere length (SL), that is, enhanced length-dependent activation. However, the mechanisms by which PKA phosphorylation of the most notable sarcomeric PKA targets, troponin I (cTnI) and myosin-binding protein C (cMyBP-C), lead to these effects remain elusive. Here, we specifically altered the phosphorylation level of cTnI in heart muscle cells and characterized the structural and functional effects at different levels of background phosphorylation of cMyBP-C and with two different SLs. We found Ser22/23 bisphosphorylation of cTnI was indispensable for the enhancement of length-dependent activation by PKA, as was cMyBP-C phosphorylation. This high level of coordination between cTnI and cMyBP-C may suggest coupling between their regulatory mechanisms. Further evidence for this was provided by our finding that cardiac troponin (cTn) can directly interact with cMyBP-C in vitro, in a phosphorylation- and Ca2+-dependent manner. In addition, bisphosphorylation at Ser22/Ser23 increased Ca2+ sensitivity at long SL in the presence of endogenously phosphorylated cMyBP-C. When cMyBP-C was dephosphorylated, bisphosphorylation of cTnI increased Ca2+ sensitivity and decreased cooperativity at both SLs, which may translate to deleterious effects in physiological settings. Our results could have clinical relevance for disease pathways, where PKA phosphorylation of cTnI may be functionally uncoupled from cMyBP-C phosphorylation due to mutations or haploinsufficiency.
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Affiliation(s)
- Ivanka R Sevrieva
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom.
| | - Saraswathi Ponnam
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Ziqian Yan
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Yin-Biao Sun
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
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11
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Joyce W, Ripley DM, Gillis T, Black AC, Shiels HA, Hoffmann FG. A Revised Perspective on the Evolution of Troponin I and Troponin T Gene Families in Vertebrates. Genome Biol Evol 2022; 15:6904147. [PMID: 36518048 PMCID: PMC9825255 DOI: 10.1093/gbe/evac173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 11/29/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
The troponin (Tn) complex, responsible for the Ca2+ activation of striated muscle, is composed of three interacting protein subunits: TnC, TnI, and TnT, encoded by TNNC, TNNI, and TNNT genes. TNNI and TNNT are sister gene families, and in mammals the three TNNI paralogs (TNNI1, TNNI2, TNNI3), which encode proteins with tissue-specific expression, are each in close genomic proximity with one of the three TNNT paralogs (TNNT2, TNNT3, TNNT1, respectively). It has been widely presumed that all vertebrates broadly possess genes of these same three classes, although earlier work has overlooked jawless fishes (cyclostomes) and cartilaginous fishes (chimeras, rays, and sharks), which are distantly related to other jawed vertebrates. With a new phylogenetic and synteny analysis of a diverse array of vertebrates including these taxonomic groups, we define five distinct TNNI classes (TNNI1-5), with TNNI4 and TNNI5 being only present in non-amniote vertebrates and typically found in tandem, and four classes of TNNT (TNNT1-4). These genes are located in four genomic loci that were generated by the 2R whole-genome duplications. TNNI3, encoding "cardiac TnI" in tetrapods, was independently lost in cartilaginous and ray-finned fishes. Instead, ray-finned fishes predominantly express TNNI1 in the heart. TNNI5 is highly expressed in shark hearts and contains a N-terminal extension similar to that of TNNI3 found in tetrapod hearts. Given that TNNI3 and TNNI5 are distantly related, this supports the hypothesis that the N-terminal extension may be an ancestral feature of vertebrate TNNI and not an innovation unique to TNNI3, as has been commonly believed.
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Affiliation(s)
| | - Daniel M Ripley
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Todd Gillis
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Amanda Coward Black
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, Mississippi 39762, USA
| | - Holly A Shiels
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, United Kingdom
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12
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Adenosine and Adenosine Receptors: Advances in Atrial Fibrillation. Biomedicines 2022; 10:biomedicines10112963. [PMID: 36428533 PMCID: PMC9687155 DOI: 10.3390/biomedicines10112963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in the world. Because the key to developing innovative therapies that limit the onset and the progression of AF is to fully understand the underlying molecular mechanisms of AF, the aim of the present narrative review is to report the most recent advances in the potential role of the adenosinergic system in the pathophysiology of AF. After a comprehensive approach describing adenosinergic system signaling and the mechanisms of the initiation and maintenance of AF, we address the interactions of the adenosinergic system's signaling with AF. Indeed, adenosine release can activate four G-coupled membrane receptors, named A1, A2A, A2B and A3. Activation of the A2A receptors can promote the occurrence of delayed depolarization, while activation of the A1 receptors can shorten the action potential's duration and induce the resting membrane's potential hyperpolarization, which promote pulmonary vein firing, stabilize the AF rotors and allow for functional reentry. Moreover, the A2B receptors have been associated with atrial fibrosis homeostasis. Finally, the adenosinergic system can modulate the autonomous nervous system and is associated with AF risk factors. A question remains regarding adenosine release and the adenosine receptors' activation and whether this would be a cause or consequence of AF.
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13
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Sarco/endoplasmic reticulum calcium ATPase activity is unchanged despite increased myofilament calcium sensitivity in Zucker type 2 diabetic fatty rat heart. Sci Rep 2022; 12:16904. [PMID: 36207382 PMCID: PMC9546843 DOI: 10.1038/s41598-022-20520-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/14/2022] [Indexed: 11/11/2022] Open
Abstract
Systolic and diastolic dysfunction in diabetes have frequently been associated with abnormal calcium (Ca2+) regulation. However, there is emerging evidence that Ca2+ mishandling alone is insufficient to fully explain diabetic heart dysfunction, with focus shifting to the properties of the myofilament proteins. Our aim was to examine the effects of diabetes on myofilament Ca2+ sensitivity and Ca2+ handling in left ventricular tissues isolated from the same type 2 diabetic rat hearts. We measured the force-pCa relationship in skinned left ventricular cardiomyocytes isolated from 20-week-old type 2 diabetic and non-diabetic rats. Myofilament Ca2+ sensitivity was greater in the diabetic relative to non-diabetic cardiomyocytes, and this corresponded with lower phosphorylation of cardiac troponin I (cTnI) at ser23/24 in the diabetic left ventricular tissues. Protein expression of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), phosphorylation of phospholamban (PLB) at Ser16, and SERCA/PLB ratio were lower in the diabetic left ventricular tissues. However, the maximum SERCA Ca2+ uptake rate was not different between the diabetic and non-diabetic myocardium. Our data suggest that impaired contractility in the diabetic heart is not caused by SERCA Ca2+ mishandling. This study highlights the important role of the cardiac myofilament and provides new insight on the pathophysiology of diabetic heart dysfunction.
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14
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Fertig B, Ling J, Nollet EE, Dobi S, Busiau T, Ishikawa K, Yamada K, Lee A, Kho C, Wills L, Tibbo AJ, Scott M, Grant K, Campbell KS, Birks EJ, MacQuaide N, Hajjar R, Smith GL, van der Velden J, Baillie GS. SUMOylation does not affect cardiac troponin I stability but alters indirectly the development of force in response to Ca 2. FEBS J 2022; 289:6267-6285. [PMID: 35633070 PMCID: PMC9588612 DOI: 10.1111/febs.16537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 03/21/2022] [Accepted: 05/26/2022] [Indexed: 11/27/2022]
Abstract
Post-translational modification of the myofilament protein troponin I by phosphorylation is known to trigger functional changes that support enhanced contraction and relaxation of the heart. We report for the first time that human troponin I can also be modified by SUMOylation at lysine 177. Functionally, TnI SUMOylation is not a factor in the development of passive and maximal force generation in response to calcium, however this modification seems to act indirectly by preventing SUMOylation of other myofilament proteins to alter calcium sensitivity and cooperativity of myofilaments. Utilising a novel, custom SUMO site-specific antibody that recognises only the SUMOylated form of troponin I, we verify that this modification occurs in human heart and that it is upregulated during disease.
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Affiliation(s)
- Bracy Fertig
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
| | - Jiayue Ling
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
| | - Edgar E. Nollet
- Department of Physiology, Amsterdam UMC, Amsterdam Cardiovascular SciencesVrije Universiteit AmsterdamThe Netherlands
| | - Sara Dobi
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
| | - Tara Busiau
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
| | | | - Kelly Yamada
- Cardiovascular Research CentreIcahn School of MedicineNew YorkNYUSA
| | - Ahyoung Lee
- Cardiovascular Research CentreIcahn School of MedicineNew YorkNYUSA
| | - Changwon Kho
- Division of Applied MedicinePusan National UniversityKorea
| | - Lauren Wills
- Department of NeuroscienceIchan School of MedicineNew YorkNYUSA
| | - Amy J. Tibbo
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
| | - Mark Scott
- INSERM, U1016, Institut CochinParisFrance
| | - Kirsten Grant
- Department of Clinical BiochemistryGlasgow Royal InfirmaryUK
| | - Kenneth S. Campbell
- Department of PhysiologyUniversity of KentuckyLexingtonKYUSA
- Division of Cardiovasuclar MedicineUniversity of KentuckyLexingtonKYUSA
| | - Emma J. Birks
- Division of Cardiovasuclar MedicineUniversity of KentuckyLexingtonKYUSA
| | - Niall MacQuaide
- School of Health and Life SciencesGlasgow Caledonian UniversityUK
| | | | - Godfrey L. Smith
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Amsterdam Cardiovascular SciencesVrije Universiteit AmsterdamThe Netherlands
- Netherlands Heart InstituteUtrechtThe Netherlands
| | - George S. Baillie
- Institute of Cardiovascular and Medical Sciences, College of Veterinary, Medical and Life SciencesGlasgow UniversityUK
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15
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Singh RR, Slater RE, Wang J, Wang C, Guo Q, Motani AS, Hartman JJ, Sadayappan S, Ason BL. Distinct Mechanisms for Increased Cardiac Contraction Through Selective Alteration of Either Myosin or Troponin Activity. JACC Basic Transl Sci 2022; 7:1021-1037. [DOI: 10.1016/j.jacbts.2022.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 10/14/2022]
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16
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Okhovatian S, Mohammadi MH, Rafatian N, Radisic M. Engineering Models of the Heart Left Ventricle. ACS Biomater Sci Eng 2022; 8:2144-2160. [PMID: 35523206 DOI: 10.1021/acsbiomaterials.1c00636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite capturing the imagination of scientists for decades, the goal of creating an artificial heart for transplantation proved to be significantly more challenging than initially anticipated. Toward this goal, recent ground-breaking studies demonstrate the development of functional left ventricular (LV) models. LV models are artificially constructed 3D chambers that are capable of containing liquid within the engineered cavity and exhibit the functionality of native LV including contraction, ejection of fluid, and electrical impulse propagation. Various hydrogels and polymers have been used in manufacturing of LV models, relying on techniques such as electrospinning, bioprinting, casting, and molding. Most studies scaled down the models based on the dimensions of the human or rat ventricle. Initially, neonatal rat cardiomyocytes were the cell type of choice for construction the LV models. Yet, as the stem cell biology field advanced, recent studies focused on the use of cardiomyocytes derived from human induced pluripotent stem cells. In this review, we first describe the physiological characteristics of the human heart, to establish the parameter space for modeling. We then elaborate on current advances in the field and compare recently developed LV models among themselves and with the native human left ventricle. Fabrication methods, cell types, biomaterials, functional properties, and disease modeling capability are some of the major parameters that have distinguished these models. We also highlight some of the current challenges in this field, such as vascularization, cell composition and fidelity, and discuss potential solutions to overcome them.
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Affiliation(s)
- Sargol Okhovatian
- Institute of Biomaterials Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Mohammad Hossein Mohammadi
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Naimeh Rafatian
- Institute of Biomaterials Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada.,Institute of Biomaterials Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada.,Toronto General Research Institute, Toronto, Ontario M5G 2C4, Canada
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17
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Critical Evaluation of Current Hypotheses for the Pathogenesis of Hypertrophic Cardiomyopathy. Int J Mol Sci 2022; 23:ijms23042195. [PMID: 35216312 PMCID: PMC8880276 DOI: 10.3390/ijms23042195] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
Hereditary hypertrophic cardiomyopathy (HCM), due to mutations in sarcomere proteins, occurs in more than 1/500 individuals and is the leading cause of sudden cardiac death in young people. The clinical course exhibits appreciable variability. However, typically, heart morphology and function are normal at birth, with pathological remodeling developing over years to decades, leading to a phenotype characterized by asymmetric ventricular hypertrophy, scattered fibrosis and myofibrillar/cellular disarray with ultimate mechanical heart failure and/or severe arrhythmias. The identity of the primary mutation-induced changes in sarcomere function and how they trigger debilitating remodeling are poorly understood. Support for the importance of mutation-induced hypercontractility, e.g., increased calcium sensitivity and/or increased power output, has been strengthened in recent years. However, other ideas that mutation-induced hypocontractility or non-uniformities with contractile instabilities, instead, constitute primary triggers cannot yet be discarded. Here, we review evidence for and criticism against the mentioned hypotheses. In this process, we find support for previous ideas that inefficient energy usage and a blunted Frank–Starling mechanism have central roles in pathogenesis, although presumably representing effects secondary to the primary mutation-induced changes. While first trying to reconcile apparently diverging evidence for the different hypotheses in one unified model, we also identify key remaining questions and suggest how experimental systems that are built around isolated primarily expressed proteins could be useful.
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18
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Lewalle A, Campbell KS, Campbell SG, Milburn GN, Niederer SA. Functional and structural differences between skinned and intact muscle preparations. J Gen Physiol 2022; 154:e202112990. [PMID: 35045156 PMCID: PMC8929306 DOI: 10.1085/jgp.202112990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 12/16/2021] [Indexed: 11/20/2022] Open
Abstract
Myofilaments and their associated proteins, which together constitute the sarcomeres, provide the molecular-level basis for contractile function in all muscle types. In intact muscle, sarcomere-level contraction is strongly coupled to other cellular subsystems, in particular the sarcolemmal membrane. Skinned muscle preparations (where the sarcolemma has been removed or permeabilized) are an experimental system designed to probe contractile mechanisms independently of the sarcolemma. Over the last few decades, experiments performed using permeabilized preparations have been invaluable for clarifying the understanding of contractile mechanisms in both skeletal and cardiac muscle. Today, the technique is increasingly harnessed for preclinical and/or pharmacological studies that seek to understand how interventions will impact intact muscle contraction. In this context, intrinsic functional and structural differences between skinned and intact muscle pose a major interpretational challenge. This review first surveys measurements that highlight these differences in terms of the sarcomere structure, passive and active tension generation, and calcium dependence. We then highlight the main practical challenges and caveats faced by experimentalists seeking to emulate the physiological conditions of intact muscle. Gaining an awareness of these complexities is essential for putting experiments in due perspective.
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Affiliation(s)
- Alex Lewalle
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | - Kenneth S. Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY
| | - Stuart G. Campbell
- Departments of Biomedical Engineering and Cellular and Molecular Physiology, Yale University, New Haven, CT
| | - Gregory N. Milburn
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY
| | - Steven A. Niederer
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
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19
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Pathophysiology of heart failure and an overview of therapies. Cardiovasc Pathol 2022. [DOI: 10.1016/b978-0-12-822224-9.00025-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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20
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Complex functionality of protein phosphatase 1 isoforms in the heart. Cell Signal 2021; 85:110059. [PMID: 34062239 DOI: 10.1016/j.cellsig.2021.110059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1(PP1) is a key regulator of cardiac function through dephosphorylating serine/threonine residues within target proteins to oppose the function of protein kinases. Studies from failing hearts of animal models and human patients have demonstrated significant increase of PP1 activity in myocardium, while elevated PP1 activity in transgenic mice leads to cardiac dysfunction, suggesting that PP1 might be a therapeutic target to ameliorate cardiac dysfunction in failing hearts. In fact, cardiac overexpression of inhibitor 1, the endogenous inhibitor of PP1, increases cardiac contractility and suppresses heart failure progression. However, this notion of PP1 inhibition for heart failure treatment has been challenged by recent studies on the isoform-specific roles of PP1 in the heart. PP1 is a holoenzyme composed of catalytic subunits (PP1α, PP1β, or PP1γ) and regulatory proteins that target them to distinct subcellular locations for functional specificity. This review will summarize how PP1 regulates phosphorylation of some of the key cardiac proteins involved in Ca2+ handling and cardiac contraction, and the potential role of PP1 isoforms in controlling cardiac physiology and pathophysiology.
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21
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Mahmud Z, Dhami PS, Rans C, Liu PB, Hwang PM. Dilated Cardiomyopathy Mutations and Phosphorylation disrupt the Active Orientation of Cardiac Troponin C. J Mol Biol 2021; 433:167010. [PMID: 33901537 DOI: 10.1016/j.jmb.2021.167010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/07/2021] [Accepted: 04/20/2021] [Indexed: 11/28/2022]
Abstract
Cardiac troponin (cTn) is made up of three subunits, cTnC, cTnI, and cTnT. The regulatory N-terminal domain of cTnC (cNTnC) controls cardiac muscle contraction in a calcium-dependent manner. We show that calcium-saturated cNTnC can adopt two different orientations, with the "active" orientation consistent with the 2020 cryo-EM structure of the activated cardiac thin filament by Yamada et al. Using solution NMR 15N R2 relaxation analysis, we demonstrate that the two domains of cTnC tumble independently (average R2 10 s-1), being connected by a flexible linker. However, upon addition of cTnI1-77, the complex tumbles as a rigid unit (R2 30 s-1). cTnI phosphomimetic mutants S22D/S23D, S41D/S43D and dilated cardiomyopathy- (DCM-)associated mutations cTnI K35Q, cTnC D75Y, and cTnC G159D destabilize the active orientation of cNTnC, with intermediate 15N R2 rates (R2 17-23 s-1). The active orientation of cNTnC is stabilized by the flexible tails of cTnI, cTnI1-37 and cTnI135-209. Surprisingly, when cTnC is incorporated into complexes lacking these tails (cTnC-cTnI38-134, cTnC-cTnT223-288, or cTnC-cTnI38-134-cTnT223-288), the cNTnC domain is still immobilized, revealing a new interaction between cNTnC and the IT-arm that stabilizes a "dormant" orientation. We propose that the calcium sensitivity of the cardiac troponin complex is regulated by an equilibrium between active and dormant orientations, which can be shifted through post-translational modifications or DCM-associated mutations.
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Affiliation(s)
- Zabed Mahmud
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Prabhpaul S Dhami
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Caleb Rans
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Philip B Liu
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Peter M Hwang
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada; Department of Medicine, University of Alberta, Edmonton, AB T6G 2R3, Canada.
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22
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Safabakhsh S, Panwar P, Barichello S, Sangha SS, Hanson PJ, Van Petegem F, Laksman Z. THE ROLE OF PHOSPHORYLATION IN ATRIAL FIBRILLATION: A FOCUS ON MASS SPECTROMETRY APPROACHES. Cardiovasc Res 2021; 118:1205-1217. [PMID: 33744917 DOI: 10.1093/cvr/cvab095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/16/2021] [Indexed: 11/14/2022] Open
Abstract
Atrial fibrillation (AF) is the most common arrhythmia worldwide. It is associated with significant increases in morbidity in the form of stroke and heart failure, and a doubling in all-cause mortality. The pathophysiology of AF is incompletely understood, and this has contributed to a lack of effective treatments and disease-modifying therapies. An important cellular process that may explain how risk factors give rise to AF includes post-translational modification (PTM) of proteins. As the most commonly occurring PTM, protein phosphorylation is especially relevant. Although many methods exist for studying protein phosphorylation, a common and highly resolute technique is mass spectrometry (MS). This review will discuss recent evidence surrounding the role of protein phosphorylation in the pathogenesis of AF. MS-based technology to study phosphorylation and uses of MS in other areas of medicine such as oncology will also be presented. Based on these data, future goals and experiments will be outlined that utilize MS technology to better understand the role of phosphorylation in AF and elucidate its role in AF pathophysiology. This may ultimately allow for the development of more effective AF therapies.
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Affiliation(s)
- Sina Safabakhsh
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pankaj Panwar
- AbCellera Biologicals Inc., Vancouver, British Columbia, Canada
| | - Scott Barichello
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarabjit S Sangha
- Cellular and Regenerative Medicine Centre, BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, British Columbia, Canada.,Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada
| | - Paul J Hanson
- UBC Heart Lung Innovation Centre, Vancouver, British Columbia, Canada.,UBC Department of Pathology and Laboratory Medicine, Vancouver, British Columbia, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zachary Laksman
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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23
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Joyce W, Wang T. How cardiac output is regulated: August Krogh's proto-Guytonian understanding of the importance of venous return. Comp Biochem Physiol A Mol Integr Physiol 2021; 253:110861. [DOI: 10.1016/j.cbpa.2020.110861] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/25/2020] [Accepted: 11/25/2020] [Indexed: 12/20/2022]
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24
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Nadur NF, de Azevedo LL, Caruso L, Graebin CS, Lacerda RB, Kümmerle AE. The long and winding road of designing phosphodiesterase inhibitors for the treatment of heart failure. Eur J Med Chem 2020; 212:113123. [PMID: 33412421 DOI: 10.1016/j.ejmech.2020.113123] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 12/14/2022]
Abstract
Cyclic nucleotide phosphodiesterases (PDEs) are a superfamily of enzymes known to play a critical role in the indirect regulation of several intracellular metabolism pathways through the selective hydrolysis of the phosphodiester bonds of specific second messenger substrates such as cAMP (3',5'-cyclic adenosine monophosphate) and cGMP (3',5'-cyclic guanosine monophosphate), influencing the hypertrophy, contractility, apoptosis and fibroses in the cardiovascular system. The expression and/or activity of multiple PDEs is altered during heart failure (HF), which leads to changes in levels of cyclic nucleotides and function of cardiac muscle. Within the cardiovascular system, PDEs 1-5, 8 and 9 are expressed and are interesting targets for the HF treatment. In this comprehensive review we will present a briefly description of the biochemical importance of each cardiovascular related PDE to the HF, and cover almost all the "long and winding road" of designing and discovering ligands, hits, lead compounds, clinical candidates and drugs as PDE inhibitors in the last decade.
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Affiliation(s)
- Nathalia Fonseca Nadur
- Laboratório de Diversidade Molecular e Química Medicinal (LaDMol-QM, Molecular Diversity and Medicinal Chemistry Laboratory), Chemistry Institute, Rural Federal University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil; Programa de Pós-Gradução em Química (PPGQ), Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil
| | - Luciana Luiz de Azevedo
- Laboratório de Diversidade Molecular e Química Medicinal (LaDMol-QM, Molecular Diversity and Medicinal Chemistry Laboratory), Chemistry Institute, Rural Federal University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil; Programa de Pós-Gradução em Química (PPGQ), Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil
| | - Lucas Caruso
- Laboratório de Diversidade Molecular e Química Medicinal (LaDMol-QM, Molecular Diversity and Medicinal Chemistry Laboratory), Chemistry Institute, Rural Federal University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil; Programa de Pós-Gradução em Química (PPGQ), Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil
| | - Cedric Stephan Graebin
- Laboratório de Diversidade Molecular e Química Medicinal (LaDMol-QM, Molecular Diversity and Medicinal Chemistry Laboratory), Chemistry Institute, Rural Federal University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil; Programa de Pós-Gradução em Química (PPGQ), Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil
| | - Renata Barbosa Lacerda
- Programa de Pós-Gradução em Química (PPGQ), Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil
| | - Arthur Eugen Kümmerle
- Laboratório de Diversidade Molecular e Química Medicinal (LaDMol-QM, Molecular Diversity and Medicinal Chemistry Laboratory), Chemistry Institute, Rural Federal University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil; Programa de Pós-Gradução em Química (PPGQ), Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil.
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25
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Clark JA, Sewanan LR, Schwan J, Kluger J, Campbell KS, Campbell SG. Fast-relaxing cardiomyocytes exert a dominant role in the relaxation behavior of heterogeneous myocardium. Arch Biochem Biophys 2020; 697:108711. [PMID: 33271148 DOI: 10.1016/j.abb.2020.108711] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/05/2020] [Accepted: 11/26/2020] [Indexed: 01/02/2023]
Abstract
Substantial variation in relaxation rate exists among cardiomyocytes within small volumes of myocardium; however, it is unknown how this variability affects the overall relaxation mechanics of heart muscle. In this study, we sought to modulate levels of cellular heterogeneity in a computational model, then validate those predictions using an engineered heart tissue platform. We formulated an in silico tissue model composed of half-sarcomeres with varied relaxation rates, incorporating single-cell cardiomyocyte experimental data. These model tissues randomly sampled relaxation parameters from two offset distributions of fast- and slow-relaxing populations of half-sarcomeres. Isometric muscle twitch simulations predicted a complex relationship between relaxation time and the proportion of fast-versus slow-relaxing cells in heterogeneous tissues. Specifically, a 50/50 mixture of fast and slow cells did not lead to relaxation time that was the mean of the relaxation times associated with the two pure cases. Rather, the mean relaxation time was achieved at a ratio of 70:30 slow:fast relaxing cells, suggesting a disproportionate impact of fast-relaxing cells on overall tissue relaxation. To examine whether this behavior persists in vitro, we constructed engineered heart tissues from two lines of fast- and slow-relaxing human iPSC-derived cardiomyocytes. Cell tracking via fluorescent nanocrystals confirmed the presence of both cell populations in the 50/50 mixed tissues at the time of mechanical characterization. Isometric muscle twitch relaxation times of these mixed-population engineered heart tissues showed agreement with the predictions from the model, namely that the measured relaxation rate of 50/50 mixed tissues more closely resembled that of tissues made with 100% fast-relaxing cells. Our observations suggest that cardiomyocyte diversity can play an important role in determining tissue-level relaxation.
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Affiliation(s)
- J Alexander Clark
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Lorenzo R Sewanan
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jonas Schwan
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jonathan Kluger
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Kenneth S Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA.
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Abstract
Heart failure (HF) is a common consequence of several cardiovascular diseases and is understood as a vicious cycle of cardiac and hemodynamic decline. The current inventory of treatments either alleviates the pathophysiological features (eg, cardiac dysfunction, neurohumoral activation, and ventricular remodeling) and/or targets any underlying pathologies (eg, hypertension and myocardial infarction). Yet, since these do not provide a cure, the morbidity and mortality associated with HF remains high. Therefore, the disease constitutes an unmet medical need, and novel therapies are desperately needed. Cyclic guanosine-3',5'-monophosphate (cGMP), synthesized by nitric oxide (NO)- and natriuretic peptide (NP)-responsive guanylyl cyclase (GC) enzymes, exerts numerous protective effects on cardiac contractility, hypertrophy, fibrosis, and apoptosis. Impaired cGMP signaling, which can occur after GC deactivation and the upregulation of cyclic nucleotide-hydrolyzing phosphodiesterases (PDEs), promotes cardiac dysfunction. In this study, we review the role that NO/cGMP and NP/cGMP signaling plays in HF. After considering disease etiology, the physiological effects of cGMP in the heart are discussed. We then assess the evidence from preclinical models and patients that compromised cGMP signaling contributes to the HF phenotype. Finally, the potential of pharmacologically harnessing cardioprotective cGMP to rectify the present paucity of effective HF treatments is examined.
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27
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Abstract
The cyclic nucleotides cyclic adenosine-3′,5′-monophosphate (cAMP) and cyclic guanosine-3′,5′-monophosphate (cGMP) maintain physiological cardiac contractility and integrity. Cyclic nucleotide–hydrolysing phosphodiesterases (PDEs) are the prime regulators of cAMP and cGMP signalling in the heart. During heart failure (HF), the expression and activity of multiple PDEs are altered, which disrupt cyclic nucleotide levels and promote cardiac dysfunction. Given that the morbidity and mortality associated with HF are extremely high, novel therapies are urgently needed. Herein, the role of PDEs in HF pathophysiology and their therapeutic potential is reviewed. Attention is given to PDEs 1–5, and other PDEs are briefly considered. After assessing the role of each PDE in cardiac physiology, the evidence from pre-clinical models and patients that altered PDE signalling contributes to the HF phenotype is examined. The potential of pharmacologically harnessing PDEs for therapeutic gain is considered.
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28
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Distinct hypertrophic cardiomyopathy genotypes result in convergent sarcomeric proteoform profiles revealed by top-down proteomics. Proc Natl Acad Sci U S A 2020; 117:24691-24700. [PMID: 32968017 PMCID: PMC7547245 DOI: 10.1073/pnas.2006764117] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common heritable heart disease. Although the genetic cause of HCM has been linked to mutations in genes encoding sarcomeric proteins, the ability to predict clinical outcomes based on specific mutations in HCM patients is limited. Moreover, how mutations in different sarcomeric proteins can result in highly similar clinical phenotypes remains unknown. Posttranslational modifications (PTMs) and alternative splicing regulate the function of sarcomeric proteins; hence, it is critical to study HCM at the level of proteoforms to gain insights into the mechanisms underlying HCM. Herein, we employed high-resolution mass spectrometry-based top-down proteomics to comprehensively characterize sarcomeric proteoforms in septal myectomy tissues from HCM patients exhibiting severe outflow track obstruction (n = 16) compared to nonfailing donor hearts (n = 16). We observed a complex landscape of sarcomeric proteoforms arising from combinatorial PTMs, alternative splicing, and genetic variation in HCM. A coordinated decrease of phosphorylation in important myofilament and Z-disk proteins with a linear correlation suggests PTM cross-talk in the sarcomere and dysregulation of protein kinase A pathways in HCM. Strikingly, we discovered that the sarcomeric proteoform alterations in the myocardium of HCM patients undergoing septal myectomy were remarkably consistent, regardless of the underlying HCM-causing mutations. This study suggests that the manifestation of severe HCM coalesces at the proteoform level despite distinct genotype, which underscores the importance of molecular characterization of HCM phenotype and presents an opportunity to identify broad-spectrum treatments to mitigate the most severe manifestations of this genetically heterogenous disease.
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29
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Eyster CA, Matsuzaki S, Newhardt MF, Giorgione JR, Humphries KM. Diabetes induced decreases in PKA signaling in cardiomyocytes: The role of insulin. PLoS One 2020; 15:e0231806. [PMID: 32817622 PMCID: PMC7444578 DOI: 10.1371/journal.pone.0231806] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/06/2020] [Indexed: 11/24/2022] Open
Abstract
The cAMP-dependent protein kinase (PKA) signaling pathway is the primary means by which the heart regulates moment-to-moment changes in contractility and metabolism. We have previously found that PKA signaling is dysfunctional in the diabetic heart, yet the underlying mechanisms are not fully understood. The objective of this study was to determine if decreased insulin signaling contributes to a dysfunctional PKA response. To do so, we isolated adult cardiomyocytes (ACMs) from wild type and Akita type 1 diabetic mice. ACMs were cultured in the presence or absence of insulin and PKA signaling was visualized by immunofluorescence microscopy using an antibody that recognizes proteins specifically phosphorylated by PKA. We found significant decreases in proteins phosphorylated by PKA in wild type ACMs cultured in the absence of insulin. PKA substrate phosphorylation was decreased in Akita ACMs, as compared to wild type, and unresponsive to the effects of insulin. The decrease in PKA signaling was observed regardless of whether the kinase was stimulated with a beta-agonist, a cell-permeable cAMP analog, or with phosphodiesterase inhibitors. PKA content was unaffected, suggesting that the decrease in PKA signaling may be occurring by the loss of specific PKA substrates. Phospho-specific antibodies were used to discern which potential substrates may be sensitive to the loss of insulin. Contractile proteins were phosphorylated similarly in wild type and Akita ACMs regardless of insulin. However, phosphorylation of the glycolytic regulator, PFK-2, was significantly decreased in an insulin-dependent manner in wild type ACMs and in an insulin-independent manner in Akita ACMs. These results demonstrate a defect in PKA activation in the diabetic heart, mediated in part by deficient insulin signaling, that results in an abnormal activation of a primary metabolic regulator.
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Affiliation(s)
- Craig A. Eyster
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Satoshi Matsuzaki
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Maria F. Newhardt
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Jennifer R. Giorgione
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Kenneth M. Humphries
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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30
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Parasuraman SK, Loudon BL, Lowery C, Cameron D, Singh S, Schwarz K, Gollop ND, Rudd A, McKiddie F, Phillips JJ, Prasad SK, Wilson AM, Sen-Chowdhry S, Clark A, Vassiliou VS, Dawson DK, Frenneaux MP. Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction. J Am Heart Assoc 2020; 8:e010114. [PMID: 30922153 PMCID: PMC6509705 DOI: 10.1161/jaha.118.010114] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background Exercise‐induced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise. Methods and Results Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at end‐diastole and end‐systole, were measured at rest and peak‐exercise, and compared between the groups. The septum was circular at rest in all 3 groups at end‐diastole. At peak‐exercise, end‐systolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. End‐diastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with end‐systolic NRC (ρ=0.51, P=0.007). In hypertensive controls and healthy controls, peak‐exercise end‐systolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, non‐significant increases in end‐diastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peak‐exercise end‐diastolic NRC also negatively correlated (r=−0.40, P<0.05) with the change in left ventricular end‐diastolic volume with exercise (ie, the Frank‐Starling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=−0.36, P=0.08). Conclusions Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the pre‐existing impaired Frank‐Starling response in these patients.
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Affiliation(s)
| | - Brodie L Loudon
- 1 Norwich Medical School University of East Anglia Norwich United Kingdom
| | - Crystal Lowery
- 1 Norwich Medical School University of East Anglia Norwich United Kingdom
| | - Donnie Cameron
- 1 Norwich Medical School University of East Anglia Norwich United Kingdom
| | | | | | - Nicholas D Gollop
- 1 Norwich Medical School University of East Anglia Norwich United Kingdom
| | - Amelia Rudd
- 4 Department of Cardiology School of Medicine & Dentistry University of Aberdeen United Kingdom
| | - Fergus McKiddie
- 5 Nuclear Medicine Aberdeen Royal Infirmary NHS Grampian Aberdeen United Kingdom
| | - Jim J Phillips
- 5 Nuclear Medicine Aberdeen Royal Infirmary NHS Grampian Aberdeen United Kingdom
| | - Sanjay K Prasad
- 6 Royal Brompton Hospital and Imperial College London London United Kingdom
| | - Andrew M Wilson
- 1 Norwich Medical School University of East Anglia Norwich United Kingdom
| | - Srijita Sen-Chowdhry
- 7 Institute of Cardiovascular Science University College London London United Kingdom
| | - Allan Clark
- 1 Norwich Medical School University of East Anglia Norwich United Kingdom
| | | | - Dana K Dawson
- 4 Department of Cardiology School of Medicine & Dentistry University of Aberdeen United Kingdom
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Chiao YA, Zhang H, Sweetwyne M, Whitson J, Ting YS, Basisty N, Pino LK, Quarles E, Nguyen NH, Campbell MD, Zhang T, Gaffrey MJ, Merrihew G, Wang L, Yue Y, Duan D, Granzier HL, Szeto HH, Qian WJ, Marcinek D, MacCoss MJ, Rabinovitch P. Late-life restoration of mitochondrial function reverses cardiac dysfunction in old mice. eLife 2020; 9:e55513. [PMID: 32648542 PMCID: PMC7377906 DOI: 10.7554/elife.55513] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/07/2020] [Indexed: 12/26/2022] Open
Abstract
Diastolic dysfunction is a prominent feature of cardiac aging in both mice and humans. We show here that 8-week treatment of old mice with the mitochondrial targeted peptide SS-31 (elamipretide) can substantially reverse this deficit. SS-31 normalized the increase in proton leak and reduced mitochondrial ROS in cardiomyocytes from old mice, accompanied by reduced protein oxidation and a shift towards a more reduced protein thiol redox state in old hearts. Improved diastolic function was concordant with increased phosphorylation of cMyBP-C Ser282 but was independent of titin isoform shift. Late-life viral expression of mitochondrial-targeted catalase (mCAT) produced similar functional benefits in old mice and SS-31 did not improve cardiac function of old mCAT mice, implicating normalizing mitochondrial oxidative stress as an overlapping mechanism. These results demonstrate that pre-existing cardiac aging phenotypes can be reversed by targeting mitochondrial dysfunction and implicate mitochondrial energetics and redox signaling as therapeutic targets for cardiac aging.
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Affiliation(s)
- Ying Ann Chiao
- Department of Pathology, University of WashingtonSeattleUnited States
- Aging and Metabolism Program, Oklahoma Medical Research FoundationOklahoma CityUnited States
| | - Huiliang Zhang
- Department of Pathology, University of WashingtonSeattleUnited States
| | - Mariya Sweetwyne
- Department of Pathology, University of WashingtonSeattleUnited States
| | - Jeremy Whitson
- Department of Pathology, University of WashingtonSeattleUnited States
| | - Ying Sonia Ting
- Department of Genome Science, University of WashingtonSeattleUnited States
| | | | - Lindsay K Pino
- Department of Genome Science, University of WashingtonSeattleUnited States
| | - Ellen Quarles
- Department of Pathology, University of WashingtonSeattleUnited States
| | - Ngoc-Han Nguyen
- Department of Pathology, University of WashingtonSeattleUnited States
| | | | - Tong Zhang
- Biological Sciences Division, Pacific Northwest National LaboratoryRichlandUnited States
| | - Matthew J Gaffrey
- Biological Sciences Division, Pacific Northwest National LaboratoryRichlandUnited States
| | - Gennifer Merrihew
- Department of Genome Science, University of WashingtonSeattleUnited States
| | - Lu Wang
- Department of Environmental and Occupational Health Sciences, University of WashingtonSeattleUnited States
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine, University of MissouriColumbiaUnited States
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of MissouriColumbiaUnited States
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine, University of ArizonaTucsonUnited States
| | | | - Wei-Jun Qian
- Biological Sciences Division, Pacific Northwest National LaboratoryRichlandUnited States
| | - David Marcinek
- Department of Radiology, University of WashingtonSeattleUnited States
| | - Michael J MacCoss
- Department of Genome Science, University of WashingtonSeattleUnited States
| | - Peter Rabinovitch
- Department of Pathology, University of WashingtonSeattleUnited States
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32
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Teigen LE, Sundberg CW, Kelly LJ, Hunter SK, Fitts RH. Ca 2+ dependency of limb muscle fiber contractile mechanics in young and older adults. Am J Physiol Cell Physiol 2020; 318:C1238-C1251. [PMID: 32348175 DOI: 10.1152/ajpcell.00575.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Age-induced declines in skeletal muscle contractile function have been attributed to multiple cellular factors, including lower peak force (Po), decreased Ca2+ sensitivity, and reduced shortening velocity (Vo). However, changes in these cellular properties with aging remain unresolved, especially in older women, and the effect of submaximal Ca2+ on contractile function is unknown. Thus, we compared contractile properties of muscle fibers from 19 young (24 ± 3 yr; 8 women) and 21 older adults (77 ± 7 yr; 7 women) under maximal and submaximal Ca2+ and assessed the abundance of three proteins thought to influence Ca2+ sensitivity. Fast fiber cross-sectional area was ~44% larger in young (6,479 ± 2,487 µm2) compared with older adults (4,503 ± 2,071 µm2, P < 0.001), which corresponded with a greater absolute Po (young = 1.12 ± 0.43 mN; old = 0.79 ± 0.33 mN, P < 0.001). There were no differences in fast fiber size-specific Po, indicating the age-related decline in force was explained by differences in fiber size. Except for fast fiber size and absolute Po, no age or sex differences were observed in Ca2+ sensitivity, rate of force development (ktr), or Vo in either slow or fast fibers. Submaximal Ca2+ depressed ktr and Vo, but the effects were not altered by age in either sex. Contrary to rodent studies, regulatory light chain (RLC) and myosin binding protein-C abundance and RLC phosphorylation were unaltered by age or sex. These data suggest the age-associated reductions in contractile function are primarily due to the atrophy of fast fibers and that caution is warranted when extending results from rodent studies to humans.
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Affiliation(s)
- Laura E Teigen
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | - Christopher W Sundberg
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin.,Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Lauren J Kelly
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | - Sandra K Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Robert H Fitts
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
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Fletcher S, Maddock H, James RS, Wallis R, Gharanei M. The cardiac work-loop technique: An in vitro model for identifying and profiling drug-induced changes in inotropy using rat papillary muscles. Sci Rep 2020; 10:5258. [PMID: 32210283 PMCID: PMC7093439 DOI: 10.1038/s41598-020-58935-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/26/2019] [Indexed: 11/09/2022] Open
Abstract
The cardiac work-loop technique closely mimics the intrinsic in vivo movement and characteristics of cardiac muscle function. In this study, six known inotropes were profiled using the work-loop technique to evaluate the potential of this method to predict inotropy. Papillary muscles from male Sprague-Dawley rats were mounted onto an organ bath perfused with Krebs-Henseleit buffer. Following optimisation, work-loop contractions were performed that included an initial stabilisation period followed by vehicle control or drug administration. Six known inotropes were tested: digoxin, dobutamine, isoprenaline, flecainide, verapamil and atenolol. Muscle performance was evaluated by calculating power output during work-loop contraction. Digoxin, dobutamine and isoprenaline caused a significant increase in power output of muscles when compared to vehicle control. Flecainide, verapamil and atenolol significantly reduced power output of muscles. These changes in power output were reflected in alterations in work loop shapes. This is the first study in which changes in work-loop shape detailing for example the activation, shortening or passive re-lengthening have been linked to the mechanism of action of a compound. This study has demonstrated that the work-loop technique can provide an important novel method with which to assess detailed mechanisms of drug-induced effects on cardiac muscle contractility.
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Affiliation(s)
- Sophie Fletcher
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, United Kingdom.,InoCardia Ltd, Technocentre, Puma Way, Coventry, CV1 2TT, UK
| | - Helen Maddock
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, United Kingdom. .,InoCardia Ltd, Technocentre, Puma Way, Coventry, CV1 2TT, UK.
| | - Rob S James
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, United Kingdom
| | - Rob Wallis
- InoCardia Ltd, Technocentre, Puma Way, Coventry, CV1 2TT, UK
| | - Mayel Gharanei
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, United Kingdom.,InoCardia Ltd, Technocentre, Puma Way, Coventry, CV1 2TT, UK
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Russell MA. Synemin Redefined: Multiple Binding Partners Results in Multifunctionality. Front Cell Dev Biol 2020; 8:159. [PMID: 32258037 PMCID: PMC7090255 DOI: 10.3389/fcell.2020.00159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/27/2020] [Indexed: 12/15/2022] Open
Abstract
Historically synemin has been studied as an intermediate filament protein. However, synemin also binds the type II regulatory (R) subunit α of protein kinase A (PKA) and protein phosphatase type 2A, thus participating in the PKA and phosphoinositide 3-kinase (PI3K)-Akt and signaling pathways. In addition, recent studies using transgenic mice indicate that a significant function of synemin is its role in signaling pathways in various tissues, including the heart. Recent clinical reports have shown that synemin mutations led to multiple cases of dilated cardiomyopathy. Additionally, a single case of the rare condition ulnar-mammary-like syndrome with left ventricular tachycardia due to a mutation in the synemin gene (SYNM) has been reported. Therefore, this review uses these recent studies to provide a new framework for detailed discussions on synemin tissue distribution, binding partners and synemin in disease. Differences between α- and β-synemin are highlighted. The studies presented here indicate that while synemin does function as an intermediate filament protein, it is unique among this large family of proteins as it is also a regulator of signaling pathways and a crosslinker. Also evident is that the dominant function(s) are isoform-, developmental-, and tissue-specific.
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Affiliation(s)
- Mary A Russell
- Department of Biological Sciences, Kent State University at Trumbull, Warren, OH, United States
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35
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Nanometric targeting of type 9 adenylyl cyclase in heart. Biochem Soc Trans 2020; 47:1749-1756. [PMID: 31769471 DOI: 10.1042/bst20190227] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/15/2022]
Abstract
Adenylyl cyclases (ACs) convert ATP into the classical second messenger cyclic adenosine monophosphate (cAMP). Cardiac ACs, specifically AC5, AC6, and AC9, regulate cAMP signaling controlling functional outcomes such as heart rate, contractility and relaxation, gene regulation, stress responses, and glucose and lipid metabolism. With so many distinct functional outcomes for a single second messenger, the cell creates local domains of cAMP signaling to correctly relay signals. Targeting of ACs to A-kinase anchoring proteins (AKAPs) not only localizes ACs, but also places them within signaling nanodomains, where cAMP levels and effects can be highly regulated. Here we will discuss the recent work on the structure, regulation and physiological functions of AC9 in the heart, where it accounts for <3% of total AC activity. Despite the small contribution of AC9 to total cardiac cAMP production, AC9 binds and regulates local PKA phosphorylation of Yotiao-IKs and Hsp20, demonstrating a role for nanometric targeting of AC9.
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36
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Sevrieva IR, Brandmeier B, Ponnam S, Gautel M, Irving M, Campbell KS, Sun YB, Kampourakis T. Cardiac myosin regulatory light chain kinase modulates cardiac contractility by phosphorylating both myosin regulatory light chain and troponin I. J Biol Chem 2020; 295:4398-4410. [PMID: 32086378 PMCID: PMC7135997 DOI: 10.1074/jbc.ra119.011945] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/14/2020] [Indexed: 12/14/2022] Open
Abstract
Heart muscle contractility and performance are controlled by posttranslational modifications of sarcomeric proteins. Although myosin regulatory light chain (RLC) phosphorylation has been studied extensively in vitro and in vivo, the precise role of cardiac myosin light chain kinase (cMLCK), the primary kinase acting upon RLC, in the regulation of cardiomyocyte contractility remains poorly understood. In this study, using recombinantly expressed and purified proteins, various analytical methods, in vitro and in situ kinase assays, and mechanical measurements in isolated ventricular trabeculae, we demonstrate that human cMLCK is not a dedicated kinase for RLC but can phosphorylate other sarcomeric proteins with well-characterized regulatory functions. We show that cMLCK specifically monophosphorylates Ser23 of human cardiac troponin I (cTnI) in isolation and in the trimeric troponin complex in vitro and in situ in the native environment of the muscle myofilament lattice. Moreover, we observed that human cMLCK phosphorylates rodent cTnI to a much smaller extent in vitro and in situ, suggesting species-specific adaptation of cMLCK. Although cMLCK treatment of ventricular trabeculae exchanged with rat or human troponin increased their cross-bridge kinetics, the increase in sensitivity of myofilaments to calcium was significantly blunted by human TnI, suggesting that human cTnI phosphorylation by cMLCK modifies the functional consequences of RLC phosphorylation. We propose that cMLCK-mediated phosphorylation of TnI is functionally significant and represents a critical signaling pathway that coordinates the regulatory states of thick and thin filaments in both physiological and potentially pathophysiological conditions of the heart.
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Affiliation(s)
- Ivanka R Sevrieva
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Birgit Brandmeier
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Saraswathi Ponnam
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Mathias Gautel
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Kenneth S Campbell
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536-0298
| | - Yin-Biao Sun
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
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37
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Marin W. A-kinase anchoring protein 1 (AKAP1) and its role in some cardiovascular diseases. J Mol Cell Cardiol 2019; 138:99-109. [PMID: 31783032 DOI: 10.1016/j.yjmcc.2019.11.154] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/08/2019] [Accepted: 11/22/2019] [Indexed: 01/09/2023]
Abstract
A-kinase anchoring proteins (AKAPs) play crucial roles in regulating compartmentalized multi-protein signaling networks related to PKA-mediated phosphorylation. The mitochondrial AKAP - AKAP1 proteins are enriched in heart and play cardiac protective roles. This review aims to thoroughly summarize AKAP1 variants from their sequence features to the structure-function relationships between AKAP1 and its binding partners, as well as the molecular mechanisms of AKAP1 in cardiac hypertrophy, hypoxia-induced myocardial infarction and endothelial cells dysfunction, suggesting AKAP1 as a candidate for cardiovascular therapy.
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Affiliation(s)
- Wenwen Marin
- Institute for Translational Medicine, Medical Faculty of Qingdao University, Qingdao 266021, China.
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38
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Clark JA, Weiss JD, Campbell SG. A Microwell Cell Capture Device Reveals Variable Response to Dobutamine in Isolated Cardiomyocytes. Biophys J 2019; 117:1258-1268. [PMID: 31537313 DOI: 10.1016/j.bpj.2019.08.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/14/2019] [Accepted: 08/22/2019] [Indexed: 12/15/2022] Open
Abstract
Isolated ventricular cardiomyocytes exhibit substantial cell-to-cell variability, even when obtained from the same small volume of myocardium. In this study, we investigated the possibility that cardiomyocyte responses to β-adrenergic stimulus are also highly heterogeneous. To achieve the throughput and measurement duration desired for these experiments, we designed and validated a novel microwell system that immobilizes and uniformly orients isolated adult cardiomyocytes. In this configuration, detailed drug responses of dozens of cells can be followed for intervals exceeding 1 h. At the conclusion of an experiment, specific cells can also be harvested via a precision aspirator for single-cell gene expression profiling. Using this system, we followed changes in Ca2+ signaling and contractility of individual cells under sustained application of either dobutamine or omecamtiv mecarbil. Both compounds increased average cardiomyocyte contractility over the course of an hour, but responses of individual cells to dobutamine were significantly more variable. Surprisingly, some dobutamine-treated cardiomyocytes augmented Ca2+ release without increasing contractility. Other cells responded with increased contractility despite unchanged Ca2+ release. Single-cell gene expression analysis revealed significant co-expression of β-adrenergic pathway genes PKA regulatory subunit type I, PKA regulatory subunit type II, and Ca2+/calmodulin-dependent protein kinase II across cardiomyocytes. Other data supported a connection between the effects of dobutamine on relaxation rate and the expression of protein phosphatase 2. These findings suggest that variable drug responses among cells are not merely experimental artifacts. By enabling direct comparison of the functional behavior of an individual cell and the genes it expresses, this new system constitutes a unique tool for interrogating cardiomyocyte drug responses and discovering the genes that modulate them.
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39
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Lieben Louis X, Raj P, Meikle Z, Yu L, Susser SE, MacInnis S, Duhamel TA, Wigle JT, Netticadan T. Resveratrol prevents palmitic-acid-induced cardiomyocyte contractile impairment. Can J Physiol Pharmacol 2019; 97:1132-1140. [PMID: 31374178 DOI: 10.1139/cjpp-2019-0051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Long-chain saturated fatty acids, especially palmitic acid (PA), contribute to cardiomyocyte lipotoxicity. This study tests the effects of PA on adult rat cardiomyocyte contractile function and proteins associated with calcium regulating cardiomyocyte contraction and relaxation. Adult rat cardiomyocytes were pretreated with resveratrol (Resv) and then treated with PA. For the reversal study, cardiomyocytes were incubated with PA prior to treatment with Resv. Cardiomyocyte contractility, ratio of rod- to round-shaped cardiomyocytes, and Hoechst staining were used to measure functional and morphological changes in cardiomyocytes. Protein expression of sarco-endoplasmic reticulum ATPase 2a (SERCA2a), native phospholamban (PLB) and phosphorylated PLB (pPLB ser16 and pPLB thr17), and troponin I (TnI) and phosphorylated TnI (pTnI) were measured. SERCA2a activity was also measured. Our results show that PA (200 μM) decreased the rate of cardiomyocyte relaxation, reduced the number of rod-shaped cardiomyocytes, and increased the number of cells with condensed nuclei; pre-treating cardiomyocytes with Resv significantly prevented these changes. Post-treatment with Resv did not reverse morphological changes induced by PA. Protein expression levels of SERCA2a, PLB, pPLBs, TnI, and pTnI were unchanged by PA or Resv. SERCA2a activity assay showed that Vmax and Iono ratio were increased with PA and pre-treatment with Resv prevented this increase. In conclusion, our results show that Resv protect cardiomyocytes from contractile dysfunction induced by PA.
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Affiliation(s)
- Xavier Lieben Louis
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada.,Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.,Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen, Research Centre, Winnipeg, MB R2H 2A6, Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Pema Raj
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.,Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen, Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Zach Meikle
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Liping Yu
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen, Research Centre, Winnipeg, MB R2H 2A6, Canada.,Agriculture and Agri-Food Canada, Winnipeg, MB R2H 2A6, Canada
| | - Shannel E Susser
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada.,Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Shayla MacInnis
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Todd A Duhamel
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada.,Health, Leisure & Human Performance Research Institute, Faculty of Kinesiology & Recreation Management, University of Manitoba, MB R3E 0J9, Canada
| | - Jeffrey T Wigle
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Thomas Netticadan
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.,Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen, Research Centre, Winnipeg, MB R2H 2A6, Canada.,Agriculture and Agri-Food Canada, Winnipeg, MB R2H 2A6, Canada
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40
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Abstract
G protein-coupled receptors (GPCRs) are critical cellular sensors that mediate numerous physiological processes. In the heart, multiple GPCRs are expressed on various cell types, where they coordinate to regulate cardiac function by modulating critical processes such as contractility and blood flow. Under pathological settings, these receptors undergo aberrant changes in expression levels, localization and capacity to couple to downstream signalling pathways. Conventional therapies for heart failure work by targeting GPCRs, such as β-adrenergic receptor and angiotensin II receptor antagonists. Although these treatments have improved patient survival, heart failure remains one of the leading causes of mortality worldwide. GPCR kinases (GRKs) are responsible for GPCR phosphorylation and, therefore, desensitization and downregulation of GPCRs. In this Review, we discuss the GPCR signalling pathways and the GRKs involved in the pathophysiology of heart disease. Given that increased expression and activity of GRK2 and GRK5 contribute to the loss of contractile reserve in the stressed and failing heart, inhibition of overactive GRKs has been proposed as a novel therapeutic approach to treat heart failure.
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41
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Lin Z, Wei L, Cai W, Zhu Y, Tucholski T, Mitchell SD, Guo W, Ford SP, Diffee GM, Ge Y. Simultaneous Quantification of Protein Expression and Modifications by Top-down Targeted Proteomics: A Case of the Sarcomeric Subproteome. Mol Cell Proteomics 2019; 18:594-605. [PMID: 30591534 PMCID: PMC6398208 DOI: 10.1074/mcp.tir118.001086] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 12/08/2018] [Indexed: 12/14/2022] Open
Abstract
Determining changes in protein expression and post-translational modifications (PTMs) is crucial for elucidating cellular signal transduction and disease mechanisms. Conventional antibody-based approaches have inherent problems such as the limited availability of high-quality antibodies and batch-to-batch variation. Top-down mass spectrometry (MS)-based proteomics has emerged as the most powerful method for characterization and quantification of protein modifications. Nevertheless, robust methods to simultaneously determine changes in protein expression and PTMs remain lacking. Herein, we have developed a straightforward and robust top-down liquid chromatography (LC)/MS-based targeted proteomics platform for simultaneous quantification of protein expression and PTMs with high throughput and high reproducibility. We employed this method to analyze the sarcomeric subproteome from various muscle types of different species, which successfully revealed skeletal muscle heterogeneity and cardiac developmental changes in sarcomeric protein isoform expression and PTMs. As demonstrated, this targeted top-down proteomics platform offers an excellent 'antibody-independent' alternative for the accurate quantification of sarcomeric protein expression and PTMs concurrently in complex mixtures, which is generally applicable to different species and various tissue types.
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Affiliation(s)
- Ziqing Lin
- From the ‡Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
- §Human Proteomics Program, University of Wisconsin-Madison, Madison, WI 53705
| | - Liming Wei
- From the ‡Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
- ¶Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, P. R. China
| | - Wenxuan Cai
- From the ‡Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
- ‖Molecular & Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705
| | - Yanlong Zhu
- From the ‡Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
- §Human Proteomics Program, University of Wisconsin-Madison, Madison, WI 53705
| | - Trisha Tucholski
- **Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Stanford D Mitchell
- From the ‡Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
- ‖Molecular & Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705
| | - Wei Guo
- ‡‡Department of Animal Science, Fetal Programming Center, University of Wyoming, Laramie, Wyoming 82071
| | - Stephen P Ford
- ‡‡Department of Animal Science, Fetal Programming Center, University of Wyoming, Laramie, Wyoming 82071
| | - Gary M Diffee
- §§Department of Kinesiology, University of Wisconsin-Madison, Madison, WI 53705
| | - Ying Ge
- From the ‡Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705;
- §Human Proteomics Program, University of Wisconsin-Madison, Madison, WI 53705
- ‖Molecular & Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705
- **Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706
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42
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Biesiadecki BJ, Westfall MV. Troponin I modulation of cardiac performance: Plasticity in the survival switch. Arch Biochem Biophys 2019; 664:9-14. [PMID: 30684464 DOI: 10.1016/j.abb.2019.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/11/2018] [Accepted: 01/22/2019] [Indexed: 01/21/2023]
Abstract
Signaling complexes targeting the myofilament are essential in modulating cardiac performance. A central target of this signaling is cardiac troponin I (cTnI) phosphorylation. This review focuses on cTnI phosphorylation as a model for myofilament signaling, discussing key gaps and future directions towards understanding complex myofilament modulation of cardiac performance. Human heart cTnI is phosphorylated at 14 sites, giving rise to a complex modulatory network of varied functional responses. For example, while classical Ser23/24 phosphorylation mediates accelerated relaxation, protein kinase C phosphorylation of cTnI serves as a brake on contractile function. Additionally, the functional response of cTnI multi-site phosphorylation cannot necessarily be predicted from the response of individual sites alone. These complexities underscore the need for systematically evaluating single and multi-site phosphorylation on myofilament cellular and in vivo contractile function. Ultimately, a complete understanding of these multi-site responses requires work to establish site occupancy and dominance, kinase/phosphatase signaling balance, and the function of adaptive secondary phosphorylation. As cTnI phosphorylation is essential for modulating cardiac performance, future insight into the complex role of cTnI phosphorylation is important to establish sarcomere signaling in the healthy heart as well as identification of novel myofilament targets in the treatment of disease.
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Affiliation(s)
- Brandon J Biesiadecki
- Department of Physiology and Cell Biology, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, 43210, USA.
| | - Margaret V Westfall
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, 48109, USA.
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43
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Is there an effect of ischemic conditioning on myocardial contractile function following acute myocardial ischemia/reperfusion injury? Biochim Biophys Acta Mol Basis Dis 2019; 1865:822-830. [PMID: 30660684 DOI: 10.1016/j.bbadis.2018.12.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
Abstract
Ischemic conditioning induces cardioprotection; the final infarct size following a myocardial ischemic event is reduced. However, whether ischemic conditioning has long-term beneficial effects on myocardial contractile function following such an ischemic event needs further elucidation. To date, ex vivo studies have shown that ischemic conditioning improves the contractile recovery of isolated ventricular papillary muscle or atrial trabeculae following simulated ischemia. However, in vivo animal studies and studies in patients undergoing elective cardiac surgery show conflicting results. At the subcellular level, it is known that ischemic conditioning improved energy metabolism, preserved mitochondrial respiration, ATP production, and Ca2+ homeostasis in isolated mitochondria from the myocardium. Ischemic conditioning also presents with post-translational modifications of proteins in the contractile machinery of the myocardium. The beneficial effects on myocardial contractile function need further elucidation. This article is part of a Special Issue entitled: The power of metabolism: Linking energy supply and demand to contractile function edited by Torsten Doenst, Michael Schwarzer and Christine Des Rosiers.
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44
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Mangmool S, Parichatikanond W, Kurose H. Therapeutic Targets for Treatment of Heart Failure: Focus on GRKs and β-Arrestins Affecting βAR Signaling. Front Pharmacol 2018; 9:1336. [PMID: 30538631 PMCID: PMC6277550 DOI: 10.3389/fphar.2018.01336] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/30/2018] [Indexed: 12/19/2022] Open
Abstract
Heart failure (HF) is a heart disease that is classified into two main types: HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Both types of HF lead to significant risk of mortality and morbidity. Pharmacological treatment with β-adrenergic receptor (βAR) antagonists (also called β-blockers) has been shown to reduce the overall hospitalization and mortality rates and improve the clinical outcomes in HF patients with HFrEF but not HFpEF. Although, the survival rate of patients suffering from HF continues to drop, the management of HF still faces several limitations and discrepancies highlighting the need to develop new treatment strategies. Overstimulation of the sympathetic nervous system is an adaptive neurohormonal response to acute myocardial injury and heart damage, whereas prolonged exposure to catecholamines causes defects in βAR regulation, including a reduction in the amount of βARs and an increase in βAR desensitization due to the upregulation of G protein-coupled receptor kinases (GRKs) in the heart, contributing in turn to the progression of HF. Several studies show that myocardial GRK2 activity and expression are raised in the failing heart. Furthermore, β-arrestins play a pivotal role in βAR desensitization and, interestingly, can mediate their own signal transduction without any G protein-dependent pathway involved. In this review, we provide new insight into the role of GRKs and β-arrestins on how they affect βAR signaling regarding the molecular and cellular pathophysiology of HF. Additionally, we discuss the therapeutic potential of targeting GRKs and β-arrestins for the treatment of HF.
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | | | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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45
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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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van Opbergen CJ, van der Voorn SM, Vos MA, de Boer TP, van Veen TA. Cardiac Ca2+ signalling in zebrafish: Translation of findings to man. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:45-58. [DOI: 10.1016/j.pbiomolbio.2018.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 05/04/2018] [Indexed: 02/07/2023]
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Cai W, Hite ZL, Lyu B, Wu Z, Lin Z, Gregorich ZR, Messer AE, McIlwain SJ, Marston SB, Kohmoto T, Ge Y. Temperature-sensitive sarcomeric protein post-translational modifications revealed by top-down proteomics. J Mol Cell Cardiol 2018; 122:11-22. [PMID: 30048711 DOI: 10.1016/j.yjmcc.2018.07.247] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/11/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022]
Abstract
Despite advancements in symptom management for heart failure (HF), this devastating clinical syndrome remains the leading cause of death in the developed world. Studies using animal models have greatly advanced our understanding of the molecular mechanisms underlying HF; however, differences in cardiac physiology and the manifestation of HF between animals, particularly rodents, and humans necessitates the direct interrogation of human heart tissue samples. Nevertheless, an ever-present concern when examining human heart tissue samples is the potential for artefactual changes related to temperature changes during tissue shipment or sample processing. Herein, we examined the effects of temperature on the post-translational modifications (PTMs) of sarcomeric proteins, the proteins responsible for muscle contraction, under conditions mimicking those that might occur during tissue shipment or sample processing. Using a powerful top-down proteomics method, we found that sarcomeric protein PTMs were differentially affected by temperature. Specifically, cardiac troponin I and enigma homolog isoform 2 showed robust increases in phosphorylation when tissue was incubated at either 4 °C or 22 °C. The observed increase is likely due to increased cyclic AMP levels and activation of protein kinase A in the tissue. On the contrary, cardiac troponin T and myosin regulatory light chain phosphorylation decreased when tissue was incubated at 4 °C or 22 °C. Furthermore, significant protein degradation was also observed after incubation at 4 °C or 22 °C. Overall, these results indicate that temperature exerts various effects on sarcomeric protein PTMs and careful tissue handling is critical for studies involving human heart samples. Moreover, these findings highlight the power of top-down proteomics for examining the integrity of cardiac tissue samples.
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Affiliation(s)
- Wenxuan Cai
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zachary L Hite
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Beini Lyu
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zhijie Wu
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ziqing Lin
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA; Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zachery R Gregorich
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Andrew E Messer
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Sean J McIlwain
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53705, USA; UW Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Steve B Marston
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Takushi Kohmoto
- Department of Surgery, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ying Ge
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA.
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Abstract
This article focuses on three "bins" that comprise sets of biophysical derangements elicited by cardiomyopathy-associated mutations in the myofilament. Current therapies focus on symptom palliation and do not address the disease at its core. We and others have proposed that a more nuanced classification could lead to direct interventions based on early dysregulation changing the trajectory of disease progression in the preclinical cohort. Continued research is necessary to address the complexity of cardiomyopathic progression and develop efficacious therapeutics.
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Affiliation(s)
- Melissa L Lynn
- Department of Medicine, University of Arizona, Room 317, 1656 East Mabel Street, Tucson, AZ 85724, USA
| | - Sarah J Lehman
- Department of Physiological Sciences, University of Arizona, Room 317, 1656 East Mabel Street, Tucson, AZ 85724, USA
| | - Jil C Tardiff
- Department of Medicine, University of Arizona, Room 312, 1656 East Mabel Street, Tucson, AZ 85724, USA.
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Menna P, Calabrese V, Armento G, Annibali O, Greco C, Salvatorelli E, Marchesi F, Reggiardo G, Minotti G. Pharmacology of Cardio-Oncology: Chronotropic and Lusitropic Effects of B-Type Natriuretic Peptide in Cancer Patients with Early Diastolic Dysfunction Induced by Anthracycline or Nonanthracycline Chemotherapy. J Pharmacol Exp Ther 2018; 366:158-168. [DOI: 10.1124/jpet.118.249235] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/30/2018] [Indexed: 12/31/2022] Open
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Role of superoxide ion formation in hypothermia/rewarming induced contractile dysfunction in cardiomyocytes. Cryobiology 2018; 81:57-64. [PMID: 29458041 DOI: 10.1016/j.cryobiol.2018.02.010] [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: 08/01/2017] [Revised: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 01/24/2023]
Abstract
Rewarming following accidental hypothermia is associated with circulatory collapse due primarily to impaired cardiac contractile (systolic) function. Previously, we found that reduced myofilament Ca2+ sensitivity underlies hypothermia/rewarming (H/R)-induced cardiac contractile dysfunction. This reduced Ca2+ sensitivity is associated with troponin I (cTnI) phosphorylation. We hypothesize that H/R induces reactive oxygen species (ROS) formation in cardiomyocytes, which leads to cTnI phosphorylation and reduced myofilament Ca2+ sensitivity. To test this hypothesis, we exposed isolated rat cardiomyocytes to a 2-h period of severe hypothermia (15 °C) followed by rewarming (35 °C) with and without antioxidant (TEMPOL) treatment. Simultaneous measurements of cytosolic Ca2+ ([Ca2+]cyto) and contractile (sarcomere shortening) responses indicated that H/R-induced contractile dysfunction and reduced Ca2+ sensitivity was prevented in cardiomyocytes treated with TEMPOL. In addition, TEMPOL treatment blunted H/R-induced cTnI phosphorylation. These results support our overall hypothesis and suggest that H/R disrupts excitation-contraction coupling of the myocardium through a cascade of event triggered by excessive ROS formation during hypothermia. Antioxidant treatment may improve successful rescue of accidental hypothermia victims.
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