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Gilda JE, Gomes AV. Proteasome dysfunction in cardiomyopathies. J Physiol 2017; 595:4051-4071. [PMID: 28181243 DOI: 10.1113/jp273607] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) plays a critical role in removing unwanted intracellular proteins and is involved in protein quality control, signalling and cell death. Because the heart is subject to continuous metabolic and mechanical stress, the proteasome plays a particularly important role in the heart, and proteasome dysfunction has been suggested as a causative factor in cardiac dysfunction. Proteasome impairment has been detected in cardiomyopathies, heart failure, myocardial ischaemia, and hypertrophy. Proteasome inhibition is also sufficient to cause cardiac dysfunction in healthy pigs, and patients using a proteasome inhibitor for cancer therapy have a higher incidence of heart failure. In this Topical Review we discuss the experimental data which suggest UPS dysfunction is a common feature of cardiomyopathies, with an emphasis on hypertrophic cardiomyopathy caused by sarcomeric mutations. We also propose potential mechanisms by which cardiomyopathy-causing mutations may lead to proteasome impairment, such as altered calcium handling and increased oxidative stress due to mitochondrial dysfunction.
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Affiliation(s)
- Jennifer E Gilda
- Department of Neurobiology, Physiology, and Behaviour, University of California, Davis, CA, 95616, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behaviour, University of California, Davis, CA, 95616, USA.,Department of Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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Mohamed IA, Krishnamoorthy NT, Nasrallah GK, Da'as SI. The Role of Cardiac Myosin Binding Protein C3 in Hypertrophic Cardiomyopathy-Progress and Novel Therapeutic Opportunities. J Cell Physiol 2017; 232:1650-1659. [PMID: 27731493 DOI: 10.1002/jcp.25639] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/07/2016] [Indexed: 11/11/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a common autosomal dominant genetic cardiovascular disorder marked by genetic and phenotypic heterogeneity. Mutations in the gene encodes the cardiac myosin-binding protein C, cMYBPC3 is amongst the various sarcomeric genes that are associated with HCM. These mutations produce mutated mRNAs and truncated cMyBP-C proteins. In this review, we will discuss the implications and molecular mechanisms involved in MYBPC3 different mutations. Further, we will highlight the novel targets that can be developed into potential therapeutics for the treatment of HMC. J. Cell. Physiol. 232: 1650-1659, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Iman A Mohamed
- Department of Biomedical Science, Zewail City of Science and Technology, Giza, Egypt
| | - Navaneethakrishnan T Krishnamoorthy
- Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - Gheyath K Nasrallah
- Department of Biomedical Science, College of Health Science, Qatar University, Doha, Qatar.,Biomedical Research Center, Qatar University, Doha, Qatar
| | - Sahar I Da'as
- Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar.,Department of Biomedical and Biological Sciences, Hamad Bin Khalifa University, Doha, Qatar
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Friedrich FW, Flenner F, Nasib M, Eschenhagen T, Carrier L. Epigallocatechin-3-Gallate Accelerates Relaxation and Ca 2+ Transient Decay and Desensitizes Myofilaments in Healthy and Mybpc3-Targeted Knock-in Cardiomyopathic Mice. Front Physiol 2016; 7:607. [PMID: 27994558 PMCID: PMC5136558 DOI: 10.3389/fphys.2016.00607] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/22/2016] [Indexed: 11/13/2022] Open
Abstract
Background: Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac muscle disease with left ventricular hypertrophy, interstitial fibrosis and diastolic dysfunction. Increased myofilament Ca2+ sensitivity could be the underlying cause of diastolic dysfunction. Epigallocatechin-3-gallate (EGCg), a catechin found in green tea, has been reported to decrease myofilament Ca2+ sensitivity in HCM models with troponin mutations. However, whether this is also the case for HCM-associated thick filament mutations is not known. Therefore, we evaluated whether EGCg affects the behavior of cardiomyocytes and myofilaments of an HCM mouse model carrying a gene mutation in cardiac myosin-binding protein C and exhibiting both increased myofilament Ca2+ sensitivity and diastolic dysfunction. Methods and Results: Acute effects of EGCg were tested on fractional sarcomere shortening and Ca2+ transients in intact ventricular myocytes and on force-Ca2+ relationship of skinned ventricular muscle strips isolated from Mybpc3-targeted knock-in (KI) and wild-type (WT) mice. Fractional sarcomere shortening and Ca2+ transients were analyzed at 37°C under 1-Hz pacing in the absence or presence of EGCg (1.8 μM). At baseline and in the absence of Fura-2, KI cardiomyocytes displayed lower diastolic sarcomere length, higher fractional sarcomere shortening, longer time to peak shortening and time to 50% relengthening than WT cardiomyocytes. In WT and KI neither diastolic sarcomere length nor fractional sarcomere shortening were influenced by EGCg treatment, but relaxation time was reduced, to a greater extent in KI cells. EGCg shortened time to peak Ca2+ and Ca2+ transient decay in Fura-2-loaded WT and KI cardiomyocytes. EGCg did not influence phosphorylation of phospholamban. In skinned cardiac muscle strips, EGCg (30 μM) decreased Ca2+ sensitivity in both groups. Conclusion: EGCg hastened relaxation and Ca2+ transient decay to a larger extent in KI than in WT cardiomyocytes. This effect could be partially explained by myofilament Ca2+ desensitization.
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Affiliation(s)
- Felix W Friedrich
- Cardiovascular Research Center, Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-EppendorfHamburg, Germany; German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Frederik Flenner
- Cardiovascular Research Center, Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-EppendorfHamburg, Germany; German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Mahtab Nasib
- Cardiovascular Research Center, Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-EppendorfHamburg, Germany; German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Thomas Eschenhagen
- Cardiovascular Research Center, Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-EppendorfHamburg, Germany; German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Lucie Carrier
- Cardiovascular Research Center, Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-EppendorfHamburg, Germany; German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
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Monteiro da Rocha A, Guerrero-Serna G, Helms A, Luzod C, Mironov S, Russell M, Jalife J, Day SM, Smith GD, Herron TJ. Deficient cMyBP-C protein expression during cardiomyocyte differentiation underlies human hypertrophic cardiomyopathy cellular phenotypes in disease specific human ES cell derived cardiomyocytes. J Mol Cell Cardiol 2016; 99:197-206. [PMID: 27620334 PMCID: PMC5609478 DOI: 10.1016/j.yjmcc.2016.09.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/18/2016] [Accepted: 09/08/2016] [Indexed: 02/07/2023]
Abstract
AIMS Mutations of cardiac sarcomere genes have been identified to cause HCM, but the molecular mechanisms that lead to cardiomyocyte hypertrophy and risk for sudden death are uncertain. The aim of this study was to examine HCM disease mechanisms at play during cardiac differentiation of human HCM specific pluripotent stem cells. METHODS AND RESULTS We generated a human embryonic stem cell (hESC) line carrying a naturally occurring mutation of MYPBC3 (c.2905 +1 G >A) to study HCM pathogenesis during cardiac differentiation. HCM-specific hESC-derived cardiomyocytes (hESC-CMs) displayed hallmark aspects of HCM including sarcomere disarray, hypertrophy and impaired calcium impulse propagation. HCM hESC-CMs presented a transient haploinsufficiency of cMyBP-C during cardiomyocyte differentiation, but by day 30 post-differentiation cMyBP-C levels were similar to control hESC-CMs. Gene transfer of full-length MYBPC3 during differentiation prevented hypertrophy, sarcomere disarray and improved calcium impulse propagation in HCM hESC-CMs. CONCLUSION(S) These findings point to the critical role of MYBPC3 during sarcomere assembly in cardiac myocyte differentiation and suggest developmental influences of MYBPC3 truncating mutations on the mature hypertrophic phenotype.
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Affiliation(s)
- Andre Monteiro da Rocha
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Guadalupe Guerrero-Serna
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Adam Helms
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Carly Luzod
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Sergey Mironov
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Mark Russell
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, United States
| | - José Jalife
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Sharlene M Day
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Gary D Smith
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Todd J Herron
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States.
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Westfall MV. Contribution of Post-translational Phosphorylation to Sarcomere-Linked Cardiomyopathy Phenotypes. Front Physiol 2016; 7:407. [PMID: 27683560 PMCID: PMC5021686 DOI: 10.3389/fphys.2016.00407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/30/2016] [Indexed: 01/24/2023] Open
Abstract
Secondary shifts develop in post-translational phosphorylation of sarcomeric proteins in multiple animal models of inherited cardiomyopathy. These signaling alterations together with the primary mutation are predicted to contribute to the overall cardiac phenotype. As a result, identification and integration of post-translational myofilament signaling responses are identified as priorities for gaining insights into sarcomeric cardiomyopathies. However, significant questions remain about the nature and contribution of post-translational phosphorylation to structural remodeling and cardiac dysfunction in animal models and human patients. This perspective essay discusses specific goals for filling critical gaps about post-translational signaling in response to these inherited mutations, especially within sarcomeric proteins. The discussion focuses primarily on pre-clinical analysis of animal models and defines challenges and future directions in this field.
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Beqqali A, Bollen IAE, Rasmussen TB, van den Hoogenhof MM, van Deutekom HWM, Schafer S, Haas J, Meder B, Sørensen KE, van Oort RJ, Mogensen J, Hubner N, Creemers EE, van der Velden J, Pinto YM. A mutation in the glutamate-rich region of RNA-binding motif protein 20 causes dilated cardiomyopathy through missplicing of titin and impaired Frank-Starling mechanism. Cardiovasc Res 2016; 112:452-63. [PMID: 27496873 DOI: 10.1093/cvr/cvw192] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/21/2016] [Indexed: 12/16/2022] Open
Abstract
AIM Mutations in the RS-domain of RNA-binding motif protein 20 (RBM20) have recently been identified to segregate with aggressive forms of familial dilated cardiomyopathy (DCM). Loss of RBM20 in rats results in missplicing of the sarcomeric gene titin (TTN). The functional and physiological consequences of RBM20 mutations outside the mutational hotspot of RBM20 have not been explored to date. In this study, we investigated the pathomechanism of DCM caused by a novel RBM20 mutation in human cardiomyocytes. METHODS AND RESULTS We identified a family with DCM carrying a mutation (RBM20(E913K/+)) in a glutamate-rich region of RBM20. Western blot analysis of endogenous RBM20 protein revealed strongly reduced protein levels in the heart of an RBM20(E913K/+ )carrier. RNA deep-sequencing demonstrated massive inclusion of exons coding for the spring region of titin in the RBM20(E913K/+ )carrier. Titin isoform analysis revealed a dramatic shift from the less compliant N2B towards the highly compliant N2BA isoforms in RBM20(E913K/+ )heart. Moreover, an increased sarcomere resting-length was observed in single cardiomyocytes and isometric force measurements revealed an attenuated Frank-Starling mechanism (FSM), which was rescued by protein kinase A treatment. CONCLUSION A mutation outside the mutational hotspot of RBM20 results in haploinsufficiency of RBM20. This leads to disturbed alternative splicing of TTN, resulting in a dramatic shift to highly compliant titin isoforms and an impaired FSM. These effects may contribute to the early onset, and malignant course of DCM caused by RBM20 mutations. Altogether, our results demonstrate that heterozygous loss of RBM20 suffices to profoundly impair myocyte biomechanics by its disturbance of TTN splicing.
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Affiliation(s)
- Abdelaziz Beqqali
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Ilse A E Bollen
- Department of Physiology, VU University Medical Center, Institute for Cardiovascular Research (ICaR-VU), van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
| | - Torsten B Rasmussen
- Department of Cardiology, Aarhus University Hospital, Norrebrogade 44, DK-8000, Aarhus, Denmark
| | - Maarten M van den Hoogenhof
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Hanneke W M van Deutekom
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Sebastian Schafer
- National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609, Singapore Division of Cardiovascular & Metabolic Disorders, Duke-National University of Singapore, 8 College Road, Singapore 169857, Singapore
| | - Jan Haas
- Department of Internal Medicine III, Cardiology, University Hospital of Heidelberg, 69120 Heidelberg, Germany DZHK (German Centre for Cardiovascular Research), Oudenarder Straße 16, 13347 Berlin, Germany
| | - Benjamin Meder
- Department of Internal Medicine III, Cardiology, University Hospital of Heidelberg, 69120 Heidelberg, Germany DZHK (German Centre for Cardiovascular Research), Oudenarder Straße 16, 13347 Berlin, Germany
| | - Keld E Sørensen
- Department of Cardiology, Aarhus University Hospital, Norrebrogade 44, DK-8000, Aarhus, Denmark
| | - Ralph J van Oort
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Jens Mogensen
- Department of Cardiology, Odense University Hospital, Sdr. Boulevard 29, 5000 Odense, Denmark
| | - Norbert Hubner
- DZHK (German Centre for Cardiovascular Research), Oudenarder Straße 16, 13347 Berlin, Germany Charité-Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany Cardiovascular and Metabolic Sciences, Max-Delbrück-Center for Molecular Medicine (MDC), Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Esther E Creemers
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Center, Institute for Cardiovascular Research (ICaR-VU), van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
| | - Yigal M Pinto
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
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The embryological basis of subclinical hypertrophic cardiomyopathy. Sci Rep 2016; 6:27714. [PMID: 27323879 PMCID: PMC4914973 DOI: 10.1038/srep27714] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/24/2016] [Indexed: 02/04/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is caused by mutations in sarcomeric proteins, the commonest being MYBPC3 encoding myosin-binding protein C. It is characterised by left ventricular hypertrophy but there is an important pre-hypertrophic phenotype with features including crypts, abnormal mitral leaflets and trabeculae. We investigated these during mouse cardiac development using high-resolution episcopic microscopy. In embryonic hearts from wildtype, homozygous (HO) and heterozygous (HET) Mybpc3-targeted knock-out (KO) mice we show that crypts (one or two) are a normal part of wildtype development but they almost all resolve by birth. By contrast, HO and HET embryos had increased crypt presence, abnormal mitral valve formation and alterations in the compaction process. In scarce normal human embryos, crypts were sometimes present. This study shows that features of the human pre-hypertrophic HCM phenotype occur in the mouse. In an animal model we demonstrate that there is an embryological HCM phenotype. Crypts are a normal part of cardiac development but, along with the mitral valve and trabeculae, their developmental trajectory is altered by the presence of HCM truncating Mybpc3 gene mutation.
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Mamidi R, Gresham KS, Verma S, Stelzer JE. Cardiac Myosin Binding Protein-C Phosphorylation Modulates Myofilament Length-Dependent Activation. Front Physiol 2016; 7:38. [PMID: 26913007 PMCID: PMC4753332 DOI: 10.3389/fphys.2016.00038] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/28/2016] [Indexed: 11/13/2022] Open
Abstract
Cardiac myosin binding protein-C (cMyBP-C) phosphorylation is an important regulator of contractile function, however, its contributions to length-dependent changes in cross-bridge (XB) kinetics is unknown. Therefore, we performed mechanical experiments to quantify contractile function in detergent-skinned ventricular preparations isolated from wild-type (WT) hearts, and hearts expressing non-phosphorylatable cMyBP-C [Ser to Ala substitutions at residues Ser273, Ser282, and Ser302 (i.e., 3SA)], at sarcomere length (SL) 1.9 μm or 2.1μm, prior and following protein kinase A (PKA) treatment. Steady-state force generation measurements revealed a blunting in the length-dependent increase in myofilament Ca(2+)-sensitivity of force generation (pCa50) following an increase in SL in 3SA skinned myocardium compared to WT skinned myocardium. Dynamic XB behavior was assessed at submaximal Ca(2+)-activations by imposing an acute rapid stretch of 2% of initial muscle length, and measuring both the magnitudes and rates of resultant phases of force decay due to strain-induced XB detachment and delayed force rise due to recruitment of additional XBs with increased SL (i.e., stretch activation). The magnitude (P2) and rate of XB detachment (k rel) following stretch was significantly reduced in 3SA skinned myocardium compared to WT skinned myocardium at short and long SL, and prior to and following PKA treatment. Furthermore, the length-dependent acceleration of k rel due to decreased SL that was observed in WT skinned myocardium was abolished in 3SA skinned myocardium. PKA treatment accelerated the rate of XB recruitment (k df) following stretch at both SL's in WT but not in 3SA skinned myocardium. The amplitude of the enhancement in force generation above initial pre-stretch steady-state levels (P3) was not different between WT and 3SA skinned myocardium at any condition measured. However, the magnitude of the entire delayed force phase which can dip below initial pre-stretch steady-state levels (Pdf) was significantly lower in 3SA skinned myocardium under all conditions, in part due to a reduced magnitude of XB detachment (P2) in 3SA skinned myocardium compared to WT skinned myocardium. These findings demonstrate that cMyBP-C phospho-ablation regulates SL- and PKA-mediated effects on XB kinetics in the myocardium, which would be expected to contribute to the regulation of the Frank-Starling mechanism.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
| | - Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
| | - Sujeet Verma
- Department of Horticultural Science, Institute of Food and Agricultural Sciences Gulf Coast Research and Education Center, University of Florida Wimauma, FL, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
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Stathopoulou K, Wittig I, Heidler J, Piasecki A, Richter F, Diering S, van der Velden J, Buck F, Donzelli S, Schröder E, Wijnker PJM, Voigt N, Dobrev D, Sadayappan S, Eschenhagen T, Carrier L, Eaton P, Cuello F. S-glutathiolation impairs phosphoregulation and function of cardiac myosin-binding protein C in human heart failure. FASEB J 2016; 30:1849-64. [PMID: 26839380 DOI: 10.1096/fj.201500048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 01/13/2016] [Indexed: 11/11/2022]
Abstract
Cardiac myosin-binding protein C (cMyBP-C) regulates actin-myosin interaction and thereby cardiac myocyte contraction and relaxation. This physiologic function is regulated by cMyBP-C phosphorylation. In our study, reduced site-specific cMyBP-C phosphorylation coincided with increased S-glutathiolation in ventricular tissue from patients with dilated or ischemic cardiomyopathy compared to nonfailing donors. We used redox proteomics, to identify constitutive and disease-specific S-glutathiolation sites in cMyBP-C in donor and patient samples, respectively. Among those, a cysteine cluster in the vicinity of the regulatory phosphorylation sites within the myosin S2 interaction domain C1-M-C2 was identified and showed enhanced S-glutathiolation in patients. In vitro S-glutathiolation of recombinant cMyBP-C C1-M-C2 occurred predominantly at Cys(249), which attenuated phosphorylation by protein kinases. Exposure to glutathione disulfide induced cMyBP-C S-glutathiolation, which functionally decelerated the kinetics of Ca(2+)-activated force development in ventricular myocytes from wild-type, but not those from Mybpc3-targeted knockout mice. These oxidation events abrogate protein kinase-mediated phosphorylation of cMyBP-C and therefore potentially contribute to the reduction of its phosphorylation and the contractile dysfunction observed in human heart failure.-Stathopoulou, K., Wittig, I., Heidler, J., Piasecki, A., Richter, F., Diering, S., van der Velden, J., Buck, F., Donzelli, S., Schröder, E., Wijnker, P. J. M., Voigt, N., Dobrev, D., Sadayappan, S., Eschenhagen, T., Carrier, L., Eaton, P., Cuello, F. S-glutathiolation impairs phosphoregulation and function of cardiac myosin-binding protein C in human heart failure.
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Affiliation(s)
- Konstantina Stathopoulou
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany
| | - Ilka Wittig
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe University, Frankfurt am Main, Germany; Cluster of Excellence "Macromolecular Complexes," Goethe University, Frankfurt am Main, Germany; Partner Site Rhein/Main, Frankfurt, Germany
| | - Juliana Heidler
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe University, Frankfurt am Main, Germany; Cluster of Excellence "Macromolecular Complexes," Goethe University, Frankfurt am Main, Germany; Partner Site Rhein/Main, Frankfurt, Germany
| | - Angelika Piasecki
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany
| | - Florian Richter
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe University, Frankfurt am Main, Germany; Cluster of Excellence "Macromolecular Complexes," Goethe University, Frankfurt am Main, Germany; Partner Site Rhein/Main, Frankfurt, Germany
| | - Simon Diering
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Amsterdam, The Netherlands; ICIN-The Netherlands Heart Institute, Utrecht, The Netherlands
| | - Friedrich Buck
- Department of Clinical Chemistry/Central Laboratories, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sonia Donzelli
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany
| | - Ewald Schröder
- King's British Heart Foundation Centre, King's College London, London, United Kingdom
| | - Paul J M Wijnker
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany; Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Niels Voigt
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany; and
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany; and
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Loyola University, Chicago, Maywood, Illinois, USA
| | - Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany
| | - Philip Eaton
- King's British Heart Foundation Centre, King's College London, London, United Kingdom
| | - Friederike Cuello
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Frankfurt, Germany;
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Najafi A, Sequeira V, Helmes M, Bollen IAE, Goebel M, Regan JA, Carrier L, Kuster DWD, Van Der Velden J. Selective phosphorylation of PKA targets after β-adrenergic receptor stimulation impairs myofilament function in Mybpc3-targeted HCM mouse model. Cardiovasc Res 2016; 110:200-14. [PMID: 26825555 DOI: 10.1093/cvr/cvw026] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 01/22/2016] [Indexed: 12/19/2022] Open
Abstract
AIMS Hypertrophic cardiomyopathy (HCM) has been associated with reduced β-adrenergic receptor (β-AR) signalling, leading downstream to a low protein kinase A (PKA)-mediated phosphorylation. It remained undefined whether all PKA targets will be affected similarly by diminished β-AR signalling in HCM. We aimed to investigate the role of β-AR signalling on regulating myofilament and calcium handling in an HCM mouse model harbouring a gene mutation (G > A transition on the last nucleotide of exon 6) in Mybpc3 encoding cardiac myosin-binding protein C. METHODS AND RESULTS Cardiomyocyte contractile properties and phosphorylation state were measured in left ventricular permeabilized and intact cardiomyocytes isolated from heterozygous (HET) or homozygous (KI) Mybpc3-targeted knock-in mice. Significantly higher myofilament Ca²⁺sensitivity and passive tension were detected in KI mice, which were normalized after PKA treatment. Loaded intact cardiomyocyte force-sarcomere length relation was impaired in both HET and KI mice, suggesting a reduced length-dependent activation. Unloaded cardiomyocyte function revealed an impaired myofilament contractile response to isoprenaline (ISO) in KI, whereas the calcium-handling response to ISO was maintained. This disparity was explained by an attenuated increase in cardiac troponin I (cTnI) phosphorylation in KI, whereas the increase in phospholamban (PLN) phosphorylation was maintained to wild-type values. CONCLUSION These data provide evidence that in the KI HCM mouse model, β-AR stimulation leads to preferential PKA phosphorylation of PLN over cTnI, resulting in an impaired inotropic and lusitropic response.
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Affiliation(s)
- Aref Najafi
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Vasco Sequeira
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Michiel Helmes
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Ilse A E Bollen
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Max Goebel
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Jessica A Regan
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Diederik W D Kuster
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Jolanda Van Der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
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Mutation-Specific Phenotypes in hiPSC-Derived Cardiomyocytes Carrying Either Myosin-Binding Protein C Or α-Tropomyosin Mutation for Hypertrophic Cardiomyopathy. Stem Cells Int 2015; 2016:1684792. [PMID: 27057166 PMCID: PMC4707351 DOI: 10.1155/2016/1684792] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/22/2015] [Accepted: 09/20/2015] [Indexed: 01/18/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disease, which affects the structure of heart muscle tissue. The clinical symptoms include arrhythmias, progressive heart failure, and even sudden cardiac death but the mutation carrier can also be totally asymptomatic. To date, over 1400 mutations have been linked to HCM, mostly in genes encoding for sarcomeric proteins. However, the pathophysiological mechanisms of the disease are still largely unknown. Two founder mutations for HCM in Finland are located in myosin-binding protein C (MYBPC3-Gln1061X) and α-tropomyosin (TPM1-Asp175Asn) genes. We studied the properties of HCM cardiomyocytes (CMs) derived from patient-specific human induced pluripotent stem cells (hiPSCs) carrying either MYBPC3-Gln1061X or TPM1-Asp175Asn mutation. Both types of HCM-CMs displayed pathological phenotype of HCM but, more importantly, we found differences between CMs carrying either MYBPC3-Gln1061X or TPM1-Asp175Asn gene mutation in their cellular size, Ca(2+) handling, and electrophysiological properties, as well as their gene expression profiles. These findings suggest that even though the clinical phenotypes of the patients carrying either MYBPC3-Gln1061X or TPM1-Asp175Asn gene mutation are similar, the genetic background as well as the functional properties on the cellular level might be different, indicating that the pathophysiological mechanisms behind the two mutations would be divergent as well.
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64
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Ntelios D, Tzimagiorgis G, Efthimiadis GK, Karvounis H. Mechanical aberrations in hypetrophic cardiomyopathy: emerging concepts. Front Physiol 2015; 6:232. [PMID: 26347658 PMCID: PMC4541419 DOI: 10.3389/fphys.2015.00232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 11/13/2022] Open
Abstract
Hypertrophic cardiomyopathy is the most common monogenic disorder in cardiology. Despite important advances in understanding disease pathogenesis, it is not clear how flaws in individual sarcomere components are responsible for the observed phenotype. The aim of this article is to provide a brief interpretative analysis of some currently proposed pathophysiological mechanisms of hypertrophic cardiomyopathy, with a special emphasis on alterations in the cardiac mechanical properties.
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Affiliation(s)
- Dimitrios Ntelios
- Laboratory of Biological Chemistry, Medical School, Aristotle University of Thessaloniki Thessaloniki, Greece ; Department of Cardiology, AHEPA University Hospital Thessaloniki, Greece
| | - Georgios Tzimagiorgis
- Laboratory of Biological Chemistry, Medical School, Aristotle University of Thessaloniki Thessaloniki, Greece
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65
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Cardiac myosin-binding protein C (MYBPC3) in cardiac pathophysiology. Gene 2015; 573:188-97. [PMID: 26358504 DOI: 10.1016/j.gene.2015.09.008] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 08/21/2015] [Accepted: 09/01/2015] [Indexed: 12/27/2022]
Abstract
More than 350 individual MYPBC3 mutations have been identified in patients with inherited hypertrophic cardiomyopathy (HCM), thus representing 40–50% of all HCM mutations, making it the most frequently mutated gene in HCM. HCM is considered a disease of the sarcomere and is characterized by left ventricular hypertrophy, myocyte disarray and diastolic dysfunction. MYBPC3 encodes for the thick filament associated protein cardiac myosin-binding protein C (cMyBP-C), a signaling node in cardiac myocytes that contributes to the maintenance of sarcomeric structure and regulation of contraction and relaxation. This review aims to provide a succinct overview of how mutations in MYBPC3 are considered to affect the physiological function of cMyBP-C, thus causing the deleterious consequences observed inHCM patients. Importantly, recent advances to causally treat HCM by repairing MYBPC3 mutations by gene therapy are discussed here, providing a promising alternative to heart transplantation for patients with a fatal form of neonatal cardiomyopathy due to bi-allelic truncating MYBPC3 mutations.
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Jensen MK, Havndrup O, Christiansen M, Andersen PS, Axelsson A, Køber L, Bundgaard H. Echocardiographic evaluation of pre-diagnostic development in young relatives genetically predisposed to hypertrophic cardiomyopathy. Int J Cardiovasc Imaging 2015; 31:1511-8. [PMID: 26231341 DOI: 10.1007/s10554-015-0723-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/25/2015] [Indexed: 11/29/2022]
Abstract
Identification of the first echocardiographic manifestations of hypertrophic cardiomyopathy may be important for clinical management and our understanding of the pathogenesis. We studied the development of pre-diagnostic echocardiographic changes in young relatives to HCM patients during long-term years follow-up. HCM-relatives not fulfilling the diagnostic criteria for HCM and age of <18 years were included in this study. We performed echocardiographic evaluations at inclusion and after 12 ± 1 years follow-up. Based on family screening of 11 sarcomere genes, CRYAB, α-GAL, and titin, we evaluated: (1) non-carriers (known family mutation ruled out-controls), (2) carriers (phenotype negative gene mutation carriers) and (3) phenotype negative relatives with unknown genetic status (relatives from families without identified mutations). At inclusion (age 11 ± 5 years), there were no differences in echocardiographic chamber dimensions, systolic or diastolic function between the three groups. During follow-up (age 23 ± 5 years), carriers (n = 8) developed lower left ventricular end-diastolic dimension (LVEDd) compared to non-carriers (n = 23) (41 ± 4 vs. 46 ± 4 mm; p = 0.04) and a higher ratio of early left ventricular filling velocity and early diastolic velocity of lateral mitral annulus (E/e' 6 ± 1 vs. 5 ± 1; p = 0.003). No significant differences in LVEDd or E/e' were found between relatives with unknown genetic status (n = 24) and non-carriers though Z-scores for these parameters were >2 in a subset of relatives with unknown genetic status. Children carrying pathogenic sarcomere gene mutations develop reduced LVEDd and increased E/e' as first pre-diagnostic echocardiographic manifestations during follow-up into adulthood.
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Affiliation(s)
- Morten K Jensen
- The Unit for Inherited Heart Diseases, The Heart Center, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
| | - Ole Havndrup
- Department of Cardiology, Roskilde Sygehus, Roskilde, Denmark
| | - Michael Christiansen
- Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark
| | - Paal S Andersen
- Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark
| | - Anna Axelsson
- The Unit for Inherited Heart Diseases, The Heart Center, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Lars Køber
- The Unit for Inherited Heart Diseases, The Heart Center, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Henning Bundgaard
- The Unit for Inherited Heart Diseases, The Heart Center, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
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Walweel K, Li J, Molenaar P, Imtiaz MS, Quail A, dos Remedios CG, Beard NA, Dulhunty AF, van Helden DF, Laver DR. Differences in the regulation of RyR2 from human, sheep, and rat by Ca²⁺ and Mg²⁺ in the cytoplasm and in the lumen of the sarcoplasmic reticulum. ACTA ACUST UNITED AC 2015; 144:263-71. [PMID: 25156119 PMCID: PMC4144672 DOI: 10.1085/jgp.201311157] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cardiac ryanodine receptors (RyR2) from humans, rats, and sheep show differential sensitivity to calcium and magnesium, with regulation of human RyR2 resembling that of sheep more than that of rat. Regulation of the cardiac ryanodine receptor (RyR2) by intracellular Ca2+ and Mg2+ plays a key role in determining cardiac contraction and rhythmicity, but their role in regulating the human RyR2 remains poorly defined. The Ca2+- and Mg2+-dependent regulation of human RyR2 was recorded in artificial lipid bilayers in the presence of 2 mM ATP and compared with that in two commonly used animal models for RyR2 function (rat and sheep). Human RyR2 displayed cytoplasmic Ca2+ activation (Ka = 4 µM) and inhibition by cytoplasmic Mg2+ (Ki = 10 µM at 100 nM Ca2+) that was similar to RyR2 from rat and sheep obtained under the same experimental conditions. However, in the presence of 0.1 mM Ca2+, RyR2s from human were 3.5-fold less sensitive to cytoplasmic Mg2+ inhibition than those from sheep and rat. The Ka values for luminal Ca2+ activation were similar in the three species (35 µM for human, 12 µM for sheep, and 10 µM for rat). From the relationship between open probability and luminal [Ca2+], the peak open probability for the human RyR2 was approximately the same as that for sheep, and both were ∼10-fold greater than that for rat RyR2. Human RyR2 also showed the same sensitivity to luminal Mg2+ as that from sheep, whereas rat RyR2 was 10-fold more sensitive. In all species, modulation of RyR2 gating by luminal Ca2+ and Mg2+ only occurred when cytoplasmic [Ca2+] was <3 µM. The activation response of RyR2 to luminal and cytoplasmic Ca2+ was strongly dependent on the Mg2+ concentration. Addition of physiological levels (1 mM) of Mg2+ raised the Ka for cytoplasmic Ca2+ to 30 µM (human and sheep) or 90 µM (rat) and raised the Ka for luminal Ca2+ to ∼1 mM in all species. This is the first report of the regulation by Ca2+ and Mg2+ of native RyR2 receptor activity from healthy human hearts.
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Affiliation(s)
- Kafa Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales 2308, Australia
| | - Jiao Li
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales 2308, Australia
| | - Peter Molenaar
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4001, Australia School of Medicine, University of Queensland, Brisbane, Queensland 4006, Australia Critical Care Research Group, The Prince Charles Hospital Foundation, Chermside, Queensland 4032, Australia
| | - Mohammad S Imtiaz
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales 2308, Australia
| | - Anthony Quail
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales 2308, Australia
| | - Cris G dos Remedios
- Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Nicole A Beard
- Faculty of Education, Science, Technology, and Mathematics, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
| | - Angela F Dulhunty
- The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2600, Australia
| | - Dirk F van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales 2308, Australia
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales 2308, Australia
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van der Velden J, Ho CY, Tardiff JC, Olivotto I, Knollmann BC, Carrier L. Research priorities in sarcomeric cardiomyopathies. Cardiovasc Res 2015; 105:449-56. [PMID: 25631582 PMCID: PMC4375392 DOI: 10.1093/cvr/cvv019] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/04/2015] [Accepted: 01/09/2015] [Indexed: 12/12/2022] Open
Abstract
The clinical variability in patients with sarcomeric cardiomyopathies is striking: a mutation causes cardiomyopathy in one individual, while the identical mutation is harmless in a family member. Moreover, the clinical phenotype varies ranging from asymmetric hypertrophy to severe dilatation of the heart. Identification of a single phenotype-associated disease mechanism would facilitate the design of targeted treatments for patient groups with different clinical phenotypes. However, evidence from both the clinic and basic knowledge of functional and structural properties of the sarcomere argues against a 'one size fits all' therapy for treatment of one clinical phenotype. Meticulous clinical and basic studies are needed to unravel the initial and progressive changes initiated by sarcomere mutations to better understand why mutations in the same gene can lead to such opposing phenotypes. Ultimately, we need to design an 'integrative physiology' approach to fully realize patient/gene-tailored therapy. Expertise within different research fields (cardiology, genetics, cellular biology, physiology, and pharmacology) must be joined to link longitudinal clinical studies with mechanistic insights obtained from molecular and functional studies in novel cardiac muscle systems. New animal models, which reflect both initial and more advanced stages of sarcomeric cardiomyopathy, will also aid in achieving these goals. Here, we discuss current priorities in clinical and preclinical investigation aimed at increasing our understanding of pathophysiological mechanisms leading from mutation to disease. Such information will provide the basis to improve risk stratification and to develop therapies to prevent/rescue cardiac dysfunction and remodelling caused by sarcomere mutations.
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Affiliation(s)
- Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, van der Boechorststraat 7, 1081BT Amsterdam, The Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Carolyn Y Ho
- Brigham and Women's Hospital, Cardiology, Boston, MA, USA
| | - Jil C Tardiff
- Department of Medicine and Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Iacopo Olivotto
- Referral Center for Cardiomyopathies, Careggi University Hospital, Florence, Italy
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
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69
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Rosas PC, Liu Y, Abdalla MI, Thomas CM, Kidwell DT, Dusio GF, Mukhopadhyay D, Kumar R, Baker KM, Mitchell BM, Powers PA, Fitzsimons DP, Patel BG, Warren CM, Solaro RJ, Moss RL, Tong CW. Phosphorylation of cardiac Myosin-binding protein-C is a critical mediator of diastolic function. Circ Heart Fail 2015; 8:582-94. [PMID: 25740839 DOI: 10.1161/circheartfailure.114.001550] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 02/24/2015] [Indexed: 01/06/2023]
Abstract
BACKGROUND Heart failure (HF) with preserved ejection fraction (HFpEF) accounts for ≈50% of all cases of HF and currently has no effective treatment. Diastolic dysfunction underlies HFpEF; therefore, elucidation of the mechanisms that mediate relaxation can provide new potential targets for treatment. Cardiac myosin-binding protein-C (cMyBP-C) is a thick filament protein that modulates cross-bridge cycling rates via alterations in its phosphorylation status. Thus, we hypothesize that phosphorylated cMyBP-C accelerates the rate of cross-bridge detachment, thereby enhancing relaxation to mediate diastolic function. METHODS AND RESULTS We compared mouse models expressing phosphorylation-deficient cMyBP-C(S273A/S282A/S302A)-cMyBP-C(t3SA), phosphomimetic cMyBP-C(S273D/S282D/S302D)-cMyBP-C(t3SD), and wild-type-control cMyBP-C(tWT) to elucidate the functional effects of cMyBP-C phosphorylation. Decreased voluntary running distances, increased lung/body weight ratios, and increased brain natriuretic peptide levels in cMyBP-C(t3SA) mice demonstrate that phosphorylation deficiency is associated with signs of HF. Echocardiography (ejection fraction and myocardial relaxation velocity) and pressure/volume measurements (-dP/dtmin, pressure decay time constant τ-Glantz, and passive filling stiffness) show that cMyBP-C phosphorylation enhances myocardial relaxation in cMyBP-C(t3SD) mice, whereas deficient cMyBP-C phosphorylation causes diastolic dysfunction with HFpEF in cMyBP-C(t3SA) mice. Simultaneous force and [Ca(2+)]i measurements on intact papillary muscles show that enhancement of relaxation in cMyBP-C(t3SD) mice and impairment of relaxation in cMyBP-C(t3SA) mice are not because of altered [Ca(2+)]i handling, implicating that altered cross-bridge detachment rates mediate these changes in relaxation rates. CONCLUSIONS cMyBP-C phosphorylation enhances relaxation, whereas deficient phosphorylation causes diastolic dysfunction and phenotypes resembling HFpEF. Thus, cMyBP-C is a potential target for treatment of HFpEF.
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Affiliation(s)
- Paola C Rosas
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Yang Liu
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Mohamed I Abdalla
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Candice M Thomas
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - David T Kidwell
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Giuseppina F Dusio
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Dhriti Mukhopadhyay
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Rajesh Kumar
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Kenneth M Baker
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Brett M Mitchell
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Patricia A Powers
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Daniel P Fitzsimons
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Bindiya G Patel
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Chad M Warren
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - R John Solaro
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Richard L Moss
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Carl W Tong
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.).
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Duncker DJ, Bakkers J, Brundel BJ, Robbins J, Tardiff JC, Carrier L. Animal and in silico models for the study of sarcomeric cardiomyopathies. Cardiovasc Res 2015; 105:439-48. [PMID: 25600962 DOI: 10.1093/cvr/cvv006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Over the past decade, our understanding of cardiomyopathies has improved dramatically, due to improvements in screening and detection of gene defects in the human genome as well as a variety of novel animal models (mouse, zebrafish, and drosophila) and in silico computational models. These novel experimental tools have created a platform that is highly complementary to the naturally occurring cardiomyopathies in cats and dogs that had been available for some time. A fully integrative approach, which incorporates all these modalities, is likely required for significant steps forward in understanding the molecular underpinnings and pathogenesis of cardiomyopathies. Finally, novel technologies, including CRISPR/Cas9, which have already been proved to work in zebrafish, are currently being employed to engineer sarcomeric cardiomyopathy in larger animals, including pigs and non-human primates. In the mouse, the increased speed with which these techniques can be employed to engineer precise 'knock-in' models that previously took years to make via multiple rounds of homologous recombination-based gene targeting promises multiple and precise models of human cardiac disease for future study. Such novel genetically engineered animal models recapitulating human sarcomeric protein defects will help bridging the gap to translate therapeutic targets from small animal and in silico models to the human patient with sarcomeric cardiomyopathy.
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Affiliation(s)
- Dirk J Duncker
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jeroen Bakkers
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bianca J Brundel
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jeff Robbins
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital, Cincinnati, OH, USA
| | - Jil C Tardiff
- Department of Medicine and Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
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71
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Mybpc3 gene therapy for neonatal cardiomyopathy enables long-term disease prevention in mice. Nat Commun 2014; 5:5515. [PMID: 25463264 DOI: 10.1038/ncomms6515] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/08/2014] [Indexed: 01/24/2023] Open
Abstract
Homozygous or compound heterozygous frameshift mutations in MYBPC3 encoding cardiac myosin-binding protein C (cMyBP-C) cause neonatal hypertrophic cardiomyopathy (HCM), which rapidly evolves into systolic heart failure and death within the first year of life. Here we show successful long-term Mybpc3 gene therapy in homozygous Mybpc3-targeted knock-in (KI) mice, which genetically mimic these human neonatal cardiomyopathies. A single systemic administration of adeno-associated virus (AAV9)-Mybpc3 in 1-day-old KI mice prevents the development of cardiac hypertrophy and dysfunction for the observation period of 34 weeks and increases Mybpc3 messenger RNA (mRNA) and cMyBP-C protein levels in a dose-dependent manner. Importantly, Mybpc3 gene therapy unexpectedly also suppresses accumulation of mutant mRNAs. This study reports the first successful long-term gene therapy of HCM with correction of both haploinsufficiency and production of poison peptides. In the absence of alternative treatment options except heart transplantation, gene therapy could become a realistic treatment option for severe neonatal HCM.
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Mamidi R, Gresham KS, Stelzer JE. Length-dependent changes in contractile dynamics are blunted due to cardiac myosin binding protein-C ablation. Front Physiol 2014; 5:461. [PMID: 25520665 PMCID: PMC4251301 DOI: 10.3389/fphys.2014.00461] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 11/10/2014] [Indexed: 12/29/2022] Open
Abstract
Enhanced cardiac contractile function with increased sarcomere length (SL) is, in part, mediated by a decrease in the radial distance between myosin heads and actin. The radial disposition of myosin heads relative to actin is modulated by cardiac myosin binding protein-C (cMyBP-C), suggesting that cMyBP-C contributes to the length-dependent activation (LDA) in the myocardium. However, the precise roles of cMyBP-C in modulating cardiac LDA are unclear. To determine the impact of cMyBP-C on LDA, we measured isometric force, myofilament Ca2+-sensitivity (pCa50) and length-dependent changes in kinetic parameters of cross-bridge (XB) relaxation (krel), and recruitment (kdf) due to rapid stretch, as well as the rate of force redevelopment (ktr) in response to a large slack-restretch maneuver in skinned ventricular multicellular preparations isolated from the hearts of wild-type (WT) and cMyBP-C knockout (KO) mice, at SL's 1.9 μm or 2.1 μm. Our results show that maximal force was not significantly different between KO and WT preparations but length-dependent increase in pCa50 was attenuated in the KO preparations. pCa50 was not significantly different between WT and KO preparations at long SL (5.82 ± 0.02 in WT vs. 5.87 ± 0.02 in KO), whereas pCa50 was significantly different between WT and KO preparations at short SL (5.71 ± 0.02 in WT vs. 5.80 ± 0.01 in KO; p < 0.05). The ktr, measured at half-maximal Ca2+-activation, was significantly accelerated at short SL in WT preparations (8.74 ± 0.56 s−1 at 1.9 μm vs. 5.71 ± 0.40 s−1 at 2.1 μm, p < 0.05). Furthermore, krel and kdf were accelerated by 32% and 50%, respectively at short SL in WT preparations. In contrast, ktr was not altered by changes in SL in KO preparations (8.03 ± 0.54 s−1 at 1.9 μm vs. 8.90 ± 0.37 s−1 at 2.1 μm). Similarly, KO preparations did not exhibit length-dependent changes in krel and kdf. Collectively, our data implicate cMyBP-C as an important regulator of LDA via its impact on dynamic XB behavior due to changes in SL.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
| | - Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
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73
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Parvatiyar MS, Pinto JR. Pathogenesis associated with a restrictive cardiomyopathy mutant in cardiac troponin T is due to reduced protein stability and greatly increased myofilament Ca2+ sensitivity. Biochim Biophys Acta Gen Subj 2014; 1850:365-72. [PMID: 25450489 DOI: 10.1016/j.bbagen.2014.09.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 01/21/2023]
Abstract
BACKGROUND Dilated and hypertrophic cardiomyopathy mutations in troponin can blunt effects of protein kinase A (PKA) phosphorylation of cardiac troponin I (cTnI), decreasing myofilament Ca2+-sensitivity; however this effect has never been tested for restrictive cardiomyopathy (RCM) mutants. This study explores whether an RCM cardiac troponin T mutant (cTnT-ΔE96) interferes with convergent PKA regulation and if TnT instability contributes to greatly enhanced Ca2+-sensitivity in skinned fibers. METHODS Force of contraction in skinned cardiac porcine fiber and spectroscopic studies were performed. RESULTS A decrease of -0.26 and -0.25 pCa units in Ca2+-sensitivity of contraction after PKA incubation was observed for skinned fibers incorporated with WT or cTnT-ΔE96, respectively. To further assess whether cTnT-ΔE96 interferes solely with transmission of cTnI phosphorylation effects, skinned fibers were reconstituted with PKA pseudo-phosphorylated cTnI (cTnI-SS/DD.cTnC). Fibers displaced with cTnT-WT, reconstituted with cTnI-SS/DD.cTnC decreased Ca2+-sensitivity of force (pCa50=5.61) compared to control cTnI-WT.cTnC (pCa50=5.75), similarly affecting cTnT-ΔE96 (pCa50=6.03) compared to control \cTnI-WT.cTnC (pCa50=6.14). Fluorescence studies measuring cTnC(IAANS) Ca2+-affinity changes due to cTnT-ΔE96 indicated that higher complexity (thin filament) better recapitulates skinned fiber Ca2+ sensitive changes. Circular dichroism revealed reduced α-helicity and earlier thermal unfolding for cTnT-ΔE96 compared to WT. CONCLUSIONS Although ineffective in decreasing myofilament Ca2+-sensitivity to normal levels, cTnT-ΔE96 does not interfere with PKA cTnI phosphorylation mediated effects; 2) cTnT-ΔE96 requires actin to increase cTnC Ca2+-affinity; and 3) deletion of E96 reduces cTnT stability, likely disrupting crucial thin filament interactions. GENERAL SIGNIFICANCE The pathological effect of cTnT-ΔE96 is largely manifested by dramatic myofilament Ca2+-sensitization which still persists even after PKA phosphorylation mediated Ca2+-desensitization.
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Affiliation(s)
- Michelle S Parvatiyar
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA.
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Friedrich FW, Reischmann S, Schwalm A, Unger A, Ramanujam D, Münch J, Müller OJ, Hengstenberg C, Galve E, Charron P, Linke WA, Engelhardt S, Patten M, Richard P, van der Velden J, Eschenhagen T, Isnard R, Carrier L. FHL2 expression and variants in hypertrophic cardiomyopathy. Basic Res Cardiol 2014; 109:451. [PMID: 25358972 PMCID: PMC4215105 DOI: 10.1007/s00395-014-0451-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 10/04/2014] [Accepted: 10/22/2014] [Indexed: 11/28/2022]
Abstract
Based on evidence that FHL2 (four and a half LIM domains protein 2) negatively regulates cardiac hypertrophy we tested whether FHL2 altered expression or variants could be associated with hypertrophic cardiomyopathy (HCM). HCM is a myocardial disease characterized by left ventricular hypertrophy, diastolic dysfunction and increased interstitial fibrosis and is mainly caused by mutations in genes coding for sarcomeric proteins. FHL2 mRNA level, FHL2 protein level and I-band-binding density were lower in HCM patients than control individuals. Screening of 121 HCM patients without mutations in established disease genes identified 2 novel (T171M, V187L) and 4 known (R177Q, N226N, D268D, P273P) FHL2 variants in unrelated HCM families. We assessed the structural and functional consequences of the nonsynonymous substitutions after adeno-associated viral-mediated gene transfer in cardiac myocytes and in 3D-engineered heart tissue (EHT). Overexpression of FHL2 wild type or nonsynonymous substitutions in cardiac myocytes markedly down-regulated α-skeletal actin and partially blunted hypertrophy induced by phenylephrine or endothelin-1. After gene transfer in EHTs, force and velocity of both contraction and relaxation were higher with T171M and V187L FHL2 variants than wild type under basal conditions. Finally, chronic phenylephrine stimulation depressed EHT function in all groups, but to a lower extent in T171M-transduced EHTs. These data suggest that (1) FHL2 is down-regulated in HCM, (2) both FHL2 wild type and variants partially protected phenylephrine- or endothelin-1-induced hypertrophy in cardiac myocytes, and (3) FHL2 T171M and V187L nonsynonymous variants induced altered EHT contractility. These findings provide evidence that the 2 novel FHL2 variants could increase cardiac function in HCM.
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Affiliation(s)
- Felix W. Friedrich
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Silke Reischmann
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Aileen Schwalm
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Andreas Unger
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | - Deepak Ramanujam
- Institute of Pharmacology and Toxicology, Technical University Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Munich, Munich, Germany
| | - Julia Münch
- University Heart Center Hamburg, Hamburg, Germany
| | - Oliver J. Müller
- Department of Cardiology, Internal Medicine III, University Hospital Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Christian Hengstenberg
- Present Address: German Heart Centre of the Technical University Munich, Munich, Germany
- Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Enrique Galve
- Unitat d’Insuficiència Cardiaca, Servei de Cardiologia, Hospital Vall d’Hebron, Barcelona, Spain
| | - Philippe Charron
- Inserm, U956, Paris, France
- ICAN Institute, UPMC Univ Paris 06, Paris, France
| | - Wolfgang A. Linke
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technical University Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Munich, Munich, Germany
| | | | - Pascale Richard
- Inserm, U956, Paris, France
- ICAN Institute, UPMC Univ Paris 06, Paris, France
- Groupe Hospitalier Pitié-Salpêtrière, AP-HP Centre de référence des maladies cardiaques héréditaires, Paris, France
- Groupe Hospitalier Pitié-Salpêtrière, AP-HP,UF Cardiogénétique et Myogénétique, Paris, France
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Richard Isnard
- Inserm, U956, Paris, France
- ICAN Institute, UPMC Univ Paris 06, Paris, France
- Groupe Hospitalier Pitié-Salpêtrière, AP-HP Centre de référence des maladies cardiaques héréditaires, Paris, France
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
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Brenner B, Seebohm B, Tripathi S, Montag J, Kraft T. Familial hypertrophic cardiomyopathy: functional variance among individual cardiomyocytes as a trigger of FHC-phenotype development. Front Physiol 2014; 5:392. [PMID: 25346696 PMCID: PMC4193225 DOI: 10.3389/fphys.2014.00392] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/22/2014] [Indexed: 11/13/2022] Open
Abstract
Familial hypertrophic cardiomyopathy (FHC) is the most frequent inherited cardiac disease. It has been related to numerous mutations in many sarcomeric and even some non-sarcomeric proteins. So far, however, no common mechanism has been identified by which the many different mutations in different sarcomeric and non-sarcomeric proteins trigger development of the FHC phenotype. Here we show for different MYH7 mutations variance in force pCa-relations from normal to highly abnormal as a feature common to all mutations we studied, while direct functional effects of the different FHC-mutations, e.g., on force generation, ATPase or calcium sensitivity of the contractile system, can be quite different. The functional variation among individual M. soleus fibers of FHC-patients is accompanied by large variation in mutant vs. wildtype β-MyHC-mRNA. Preliminary results show a similar variation in mutant vs. wildtype β-MyHC-mRNA among individual cardiomyocytes. We discuss our previously proposed concept as to how different mutations in the β-MyHC and possibly other sarcomeric and non-sarcomeric proteins may initiate an FHC-phenotype by functional variation among individual cardiomyocytes that results in structural distortions within the myocardium, leading to cellular and myofibrillar disarray. In addition, distortions can activate stretch-sensitive signaling in cardiomyocytes and non-myocyte cells which is known to induce cardiac remodeling with interstitial fibrosis and hypertrophy. Such a mechanism will have major implications for therapeutic strategies to prevent FHC-development, e.g., by reducing functional imbalances among individual cardiomyocytes or by inhibition of their triggering of signaling paths initiating remodeling. Targeting increased or decreased contractile function would require selective targeting of mutant or wildtype protein to reduce functional imbalances.
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Affiliation(s)
- Bernhard Brenner
- Institute of Molecular and Cell Physiology, Hannover Medical School Hannover, Germany
| | - Benjamin Seebohm
- Institute of Molecular and Cell Physiology, Hannover Medical School Hannover, Germany
| | - Snigdha Tripathi
- Institute of Molecular and Cell Physiology, Hannover Medical School Hannover, Germany
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School Hannover, Germany
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School Hannover, Germany
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Wijnker PJM, Murphy AM, Stienen GJM, van der Velden J. Troponin I phosphorylation in human myocardium in health and disease. Neth Heart J 2014; 22:463-9. [PMID: 25200323 PMCID: PMC4188840 DOI: 10.1007/s12471-014-0590-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Cardiac troponin I (cTnI) is well known as a biomarker for the diagnosis of myocardial damage. However, because of its central role in the regulation of contraction and relaxation in heart muscle, cTnI may also be a potential target for the treatment of heart failure. Studies in rodent models of cardiac disease and human heart samples showed altered phosphorylation at various sites on cTnI (i.e. site-specific phosphorylation). This is caused by altered expression and/or activity of kinases and phosphatases during heart failure development. It is not known whether these (transient) alterations in cTnI phosphorylation are beneficial or detrimental. Knowledge of the effects of site-specific cTnI phosphorylation on cardiomyocyte contractility is therefore of utmost importance for the development of new therapeutic strategies in patients with heart failure. In this review we focus on the role of cTnI phosphorylation in the healthy heart upon activation of the beta-adrenergic receptor pathway (as occurs during increased stress and exercise) and as a modulator of the Frank-Starling mechanism. Moreover, we provide an overview of recent studies which aimed to reveal the functional consequences of changes in cTnI phosphorylation in cardiac disease.
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Affiliation(s)
- P J M Wijnker
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Van der Boechorststraat 7, 1081, BT, Amsterdam, the Netherlands,
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Manders E, Bogaard HJ, Handoko ML, van de Veerdonk MC, Keogh A, Westerhof N, Stienen GJM, Dos Remedios CG, Humbert M, Dorfmüller P, Fadel E, Guignabert C, van der Velden J, Vonk-Noordegraaf A, de Man FS, Ottenheijm CAC. Contractile dysfunction of left ventricular cardiomyocytes in patients with pulmonary arterial hypertension. J Am Coll Cardiol 2014; 64:28-37. [PMID: 24998125 DOI: 10.1016/j.jacc.2014.04.031] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND After lung transplantation, increased left ventricular (LV) filling can lead to LV failure, increasing the risk of post-operative complications and mortality. LV dysfunction in pulmonary arterial hypertension (PAH) is characterized by a reduced LV ejection fraction and impaired diastolic function. OBJECTIVES The pathophysiology of LV dysfunction in PAH is incompletely understood. This study sought to assess the contribution of atrophy and contractility of cardiomyocytes to LV dysfunction in PAH patients. METHODS LV function was assessed by cardiac magnetic resonance imaging. In addition, LV biopsies were obtained in 9 PAH patients and 10 donors. The cross-sectional area (CSA) and force-generating capacity of isolated single cardiomyocytes was investigated. RESULTS Magnetic resonance imaging analysis revealed a significant reduction in LV ejection fraction in PAH patients, indicating a reduction in LV contractility. The CSA of LV cardiomyocytes of PAH patients was significantly reduced (~30%), indicating LV cardiomyocyte atrophy. The maximal force-generating capacity, normalized to cardiomyocyte CSA, was significantly reduced (~25%). Also, a reduction in the number of available myosin-based cross-bridges was found to cause the contractile weakness of cardiomyocytes. This finding was supported by protein analyses, which showed an ~30% reduction in the myosin/actin ratio in cardiomyocytes from PAH patients. Finally, the phosphorylation level of sarcomeric proteins was reduced in PAH patients, which was accompanied by increased calcium sensitivity of force generation. CONCLUSIONS The contractile function and the CSA of LV cardiomyocytes is substantially reduced in PAH patients. We propose that these changes contribute to the reduced in vivo contractility of the LV in PAH patients.
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Affiliation(s)
- Emmy Manders
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands; Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Harm-Jan Bogaard
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands
| | - M Louis Handoko
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Cardiology Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Marielle C van de Veerdonk
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands
| | - Anne Keogh
- Heart Transplant Unit, St. Vincent's Hospital, Sydney, Australia
| | - Nico Westerhof
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands; Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ger J M Stienen
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Department of Physics and Astronomy, VU University, Amsterdam, the Netherlands
| | | | - Marc Humbert
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Assistance Publique-Hôpitaux de Paris, Service de Pneumologie, Département Hospitalo-Universitaire, Thorax Innovation (DHU TORINO), Hôpital Bicêtre, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Peter Dorfmüller
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; Service d'Anatomie Pathologique, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Elie Fadel
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; Service de Chirurgie Thoracique, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Christophe Guignabert
- University of Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France; Inserm U999, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LabEx LERMIT), Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; ICIN Netherlands Heart Institute, Utrecht, the Netherlands
| | - Anton Vonk-Noordegraaf
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands
| | - Frances S de Man
- Department of Pulmonology, Vrije Universiteit (VU) University Medical Center, Amsterdam, the Netherlands.
| | - Coen A C Ottenheijm
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands.
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Helms AS, Davis FM, Coleman D, Bartolone SN, Glazier AA, Pagani F, Yob JM, Sadayappan S, Pedersen E, Lyons R, Westfall MV, Jones R, Russell MW, Day SM. Sarcomere mutation-specific expression patterns in human hypertrophic cardiomyopathy. ACTA ACUST UNITED AC 2014; 7:434-43. [PMID: 25031304 DOI: 10.1161/circgenetics.113.000448] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Heterozygous mutations in sarcomere genes in hypertrophic cardiomyopathy (HCM) are proposed to exert their effect through gain of function for missense mutations or loss of function for truncating mutations. However, allelic expression from individual mutations has not been sufficiently characterized to support this exclusive distinction in human HCM. METHODS AND RESULTS Sarcomere transcript and protein levels were analyzed in septal myectomy and transplant specimens from 46 genotyped HCM patients with or without sarcomere gene mutations and 10 control hearts. For truncating mutations in MYBPC3, the average ratio of mutant:wild-type transcripts was ≈1:5, in contrast to ≈1:1 for all sarcomere missense mutations, confirming that nonsense transcripts are uniquely unstable. However, total MYBPC3 mRNA was significantly increased by 9-fold in HCM samples with MYBPC3 mutations compared with control hearts and with HCM samples without sarcomere gene mutations. Full-length MYBPC3 protein content was not different between MYBPC3 mutant HCM and control samples, and no truncated proteins were detected. By absolute quantification of abundance with multiple reaction monitoring, stoichiometric ratios of mutant sarcomere proteins relative to wild type were strikingly variable in a mutation-specific manner, with the fraction of mutant protein ranging from 30% to 84%. CONCLUSIONS These results challenge the concept that haploinsufficiency is a unifying mechanism for HCM caused by MYBPC3 truncating mutations. The range of allelic imbalance for several missense sarcomere mutations suggests that certain mutant proteins may be more or less stable or incorporate more or less efficiently into the sarcomere than wild-type proteins. These mutation-specific properties may distinctly influence disease phenotypes.
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Affiliation(s)
- Adam S Helms
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Frank M Davis
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - David Coleman
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Sarah N Bartolone
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Amelia A Glazier
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Francis Pagani
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Jaime M Yob
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Sakthivel Sadayappan
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Ellen Pedersen
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Robert Lyons
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Margaret V Westfall
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Richard Jones
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Mark W Russell
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.)
| | - Sharlene M Day
- From the Departments of Internal Medicine (A.S.H., F.D., D.C., S.B., J.M.Y., S.M.D.), Molecular and Integrative Physiology (A.A.G., M.V.W.), Cardiac Surgery (F.P., M.V.W.), Sequencing Core (E.P., R.L.), and Pediatrics (M.W.R.), University of Michigan, Ann Arbor; Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, IL (S.S.); and MS Bioworks, Ann Arbor, MI (R.J.).
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79
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Lynch TL, Sadayappan S. Surviving the infarct: A profile of cardiac myosin binding protein-C pathogenicity, diagnostic utility, and proteomics in the ischemic myocardium. Proteomics Clin Appl 2014; 8:569-77. [PMID: 24888514 PMCID: PMC4162529 DOI: 10.1002/prca.201400011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/31/2014] [Accepted: 05/20/2014] [Indexed: 12/17/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) is a regulatory protein of the contractile apparatus within the cardiac sarcomere. Ischemic injury to the heart during myocardial infarction (MI) results in the cleavage of cMyBP-C in a phosphorylation-dependent manner and release of an N-terminal fragment (C0C1f) into the circulation. C0C1f has been shown to be pathogenic within cardiac tissue, leading to the development of heart failure. Based on its high levels and early release into the circulation post-MI, C0C1f may serve as a novel biomarker for diagnosing MI more effectively than current clinically used biomarkers. Over time, circulating C0C1f could trigger an autoimmune response leading to myocarditis and progressive cardiac dysfunction. Given the importance of cMyBP-C phosphorylation state in the context of proteolytic cleavage and release into the circulation post-MI, understanding the posttranslational modifications (PTMs) of cMyBP-C would help in further elucidating the role of this protein in health and disease. Accordingly, recent studies have implemented the latest proteomics approaches to define the PTMs of cMyBP-C. The use of such proteomics assays may provide accurate quantitation of the levels of cMyBP-C in the circulation following MI, which could, in turn, demonstrate the efficacy of using plasma cMyBP-C as a cardiac-specific early biomarker of MI. In this review, we define the pathogenic and potential immunogenic effects of C0C1f on cardiac function in the post-MI heart. We also discuss the most advanced proteomics approaches now used to determine cMyBP-C PTMs with the aim of validating C0C1f as an early biomarker of MI.
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Affiliation(s)
- Thomas L Lynch
- Division of Cardiology, Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
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80
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Najafi A, Schlossarek S, van Deel ED, van den Heuvel N, Güçlü A, Goebel M, Kuster DWD, Carrier L, van der Velden J. Sexual dimorphic response to exercise in hypertrophic cardiomyopathy-associated MYBPC3-targeted knock-in mice. Pflugers Arch 2014; 467:1303-17. [PMID: 25010737 DOI: 10.1007/s00424-014-1570-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 06/27/2014] [Accepted: 06/27/2014] [Indexed: 01/02/2023]
Abstract
Hypertrophic cardiomyopathy (HCM), the most common genetic cardiac disorder, is frequently caused by mutations in MYBPC3, encoding cardiac myosin-binding protein C (cMyBP-C). Moreover, HCM is the leading cause of sudden cardiac death (SCD) in young athletes. Interestingly, SCD is more likely to occur in male than in female athletes. However, the pathophysiological mechanisms leading to sex-specific differences are poorly understood. Therefore, we studied the effect of sex and exercise on functional properties of the heart and sarcomeres in mice carrying a MYBPC3 point mutation (G > A transition in exon 6) associated with human HCM. Echocardiography followed by isometric force measurements in left ventricular (LV) membrane-permeabilized cardiomyocytes was performed in wild-type (WT) and heterozygous (HET) knock-in mice of both sex (N = 5 per group) in sedentary mice and mice that underwent an 8-week voluntary wheel-running exercise protocol. Isometric force measurements in single cardiomyocytes revealed a lower maximal force generation (F max) of the sarcomeres in male sedentary HET (13.0 ± 1.1 kN/m(2)) compared to corresponding WT (18.4 ± 1.8 kN/m(2)) male mice. Exercise induced a higher F max in HET male mice, while it did not affect HET females. Interestingly, a low cardiac troponin I bisphosphorylation, increased myofilament Ca(2+)-sensitivity, and LV hypertrophy were particularly observed in exercised HET females. In conclusion, in sedentary animals, contractile differences are seen between male and female HET mice. Male and female HET hearts adapted differently to a voluntary exercise protocol, indicating that physiological stimuli elicit a sexually dimorphic cardiac response in heterozygous MYBPC3-targeted knock-in mice.
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Affiliation(s)
- Aref Najafi
- Department of Physiology, VU University Medical Center, Room B-156, Van der Boechorstraat 7, 1081 BT, Amsterdam, The Netherlands,
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81
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Dweck D, Sanchez-Gonzalez MA, Chang AN, Dulce RA, Badger CD, Koutnik AP, Ruiz EL, Griffin B, Liang J, Kabbaj M, Fincham FD, Hare JM, Overton JM, Pinto JR. Long term ablation of protein kinase A (PKA)-mediated cardiac troponin I phosphorylation leads to excitation-contraction uncoupling and diastolic dysfunction in a knock-in mouse model of hypertrophic cardiomyopathy. J Biol Chem 2014; 289:23097-23111. [PMID: 24973218 DOI: 10.1074/jbc.m114.561472] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cardiac troponin I (cTnI) R21C (cTnI-R21C) mutation has been linked to hypertrophic cardiomyopathy and renders cTnI incapable of phosphorylation by PKA in vivo. Echocardiographic imaging of homozygous knock-in mice expressing the cTnI-R21C mutation shows that they develop hypertrophy after 12 months of age and have abnormal diastolic function that is characterized by longer filling times and impaired relaxation. Electrocardiographic analyses show that older R21C mice have elevated heart rates and reduced cardiovagal tone. Cardiac myocytes isolated from older R21C mice demonstrate that in the presence of isoproterenol, significant delays in Ca(2+) decay and sarcomere relaxation occur that are not present at 6 months of age. Although isoproterenol and stepwise increases in stimulation frequency accelerate Ca(2+)-transient and sarcomere shortening kinetics in R21C myocytes from older mice, they are unable to attain the corresponding WT values. When R21C myocytes from older mice are treated with isoproterenol, evidence of excitation-contraction uncoupling is indicated by an elevation in diastolic calcium that is frequency-dissociated and not coupled to shorter diastolic sarcomere lengths. Myocytes from older mice have smaller Ca(2+) transient amplitudes (2.3-fold) that are associated with reductions (2.9-fold) in sarcoplasmic reticulum Ca(2+) content. This abnormal Ca(2+) handling within the cell may be attributed to a reduction (2.4-fold) in calsequestrin expression in conjunction with an up-regulation (1.5-fold) of Na(+)-Ca(2+) exchanger. Incubation of permeabilized cardiac fibers from R21C mice with PKA confirmed that the mutation prevents facilitation of mechanical relaxation. Altogether, these results indicate that the inability to enhance myofilament relaxation through cTnI phosphorylation predisposes the heart to abnormal diastolic function, reduced accessibility of cardiac reserves, dysautonomia, and hypertrophy.
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Affiliation(s)
- David Dweck
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Marcos A Sanchez-Gonzalez
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300,; Family Institute, Florida State University, Tallahassee, Florida 32306
| | - Audrey N Chang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040
| | - Raul A Dulce
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - Crystal-Dawn Badger
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Andrew P Koutnik
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Edda L Ruiz
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Brittany Griffin
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Mohamed Kabbaj
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Frank D Fincham
- Family Institute, Florida State University, Tallahassee, Florida 32306
| | - Joshua M Hare
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - J Michael Overton
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300,.
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82
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Witjas-Paalberends ER, Güçlü A, Germans T, Knaapen P, Harms HJ, Vermeer AMC, Christiaans I, Wilde AAM, Dos Remedios C, Lammertsma AA, van Rossum AC, Stienen GJM, van Slegtenhorst M, Schinkel AF, Michels M, Ho CY, Poggesi C, van der Velden J. Gene-specific increase in the energetic cost of contraction in hypertrophic cardiomyopathy caused by thick filament mutations. Cardiovasc Res 2014; 103:248-57. [PMID: 24835277 DOI: 10.1093/cvr/cvu127] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Disease mechanisms regarding hypertrophic cardiomyopathy (HCM) are largely unknown and disease onset varies. Sarcomere mutations might induce energy depletion for which until now there is no direct evidence at sarcomere level in human HCM. This study investigated if mutations in genes encoding myosin-binding protein C (MYBPC3) and myosin heavy chain (MYH7) underlie changes in the energetic cost of contraction in the development of human HCM disease. METHODS AND RESULTS Energetic cost of contraction was studied in vitro by measurements of force development and ATPase activity in cardiac muscle strips from 26 manifest HCM patients (11 MYBPC3mut, 9 MYH7mut, and 6 sarcomere mutation-negative, HCMsmn). In addition, in vivo, the ratio between external work (EW) and myocardial oxygen consumption (MVO2) to obtain myocardial external efficiency (MEE) was determined in 28 pre-hypertrophic mutation carriers (14 MYBPC3mut and 14 MYH7mut) and 14 healthy controls using [(11)C]-acetate positron emission tomography and cardiovascular magnetic resonance imaging. Tension cost (TC), i.e. ATPase activity during force development, was higher in MYBPC3mut and MYH7mut compared with HCMsmn at saturating [Ca(2+)]. TC was also significantly higher in MYH7mut at submaximal, more physiological [Ca(2+)]. EW was significantly lower in both mutation carrier groups, while MVO2 did not differ. MEE was significantly lower in both mutation carrier groups compared with controls, showing the lowest efficiency in MYH7 mutation carriers. CONCLUSION We provide direct evidence that sarcomere mutations perturb the energetic cost of cardiac contraction. Gene-specific severity of cardiac abnormalities may underlie differences in disease onset and suggests that early initiation of metabolic treatment may be beneficial, in particular, in MYH7 mutation carriers.
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Affiliation(s)
- E Rosalie Witjas-Paalberends
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Ahmet Güçlü
- Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands ICIN Netherlands Heart Institute, Utrecht, The Netherlands
| | - Tjeerd Germans
- Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Paul Knaapen
- Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Hendrik J Harms
- Department of Radiology and Nuclear Medicine, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Alexa M C Vermeer
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Imke Christiaans
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Arthur A M Wilde
- Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Cris Dos Remedios
- Institute for Biomedical Research, Muscle Research Unit, University of Sydney, Sydney, Australia
| | - Adriaan A Lammertsma
- Department of Radiology and Nuclear Medicine, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Albert C van Rossum
- Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Ger J M Stienen
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands
| | | | - Arend F Schinkel
- Thorax Center, Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Michelle Michels
- Thorax Center, Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carolyn Y Ho
- Brigham and Women's Hospital, Cardiology, Boston, MA, USA
| | - Corrado Poggesi
- Department of Physiology, University of Florence, Florence, Italy
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands ICIN Netherlands Heart Institute, Utrecht, The Netherlands
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83
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Barefield D, Kumar M, de Tombe PP, Sadayappan S. Contractile dysfunction in a mouse model expressing a heterozygous MYBPC3 mutation associated with hypertrophic cardiomyopathy. Am J Physiol Heart Circ Physiol 2014; 306:H807-15. [PMID: 24464755 PMCID: PMC3949045 DOI: 10.1152/ajpheart.00913.2013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/19/2014] [Indexed: 12/29/2022]
Abstract
The etiology of hypertrophic cardiomyopathy (HCM) has been ascribed to mutations in genes encoding sarcomere proteins. In particular, mutations in MYBPC3, a gene which encodes cardiac myosin binding protein-C (cMyBP-C), have been implicated in over one third of HCM cases. Of these mutations, 70% are predicted to result in C'-truncated protein products, which are undetectable in tissue samples. Heterozygous carriers of these truncation mutations exhibit varying penetrance of HCM, with symptoms often occurring later in life. We hypothesize that heterozygous carriers of MYBPC3 mutations, while seemingly asymptomatic, have subtle functional impairments that precede the development of overt HCM. This study compared heterozygous (+/t) knock-in MYBPC3 truncation mutation mice with wild-type (+/+) littermates to determine whether functional alterations occur at the whole-heart or single-cell level before the onset of hypertrophy. The +/t mice show ∼40% reduction in MYBPC3 transcription, but no changes in cMyBP-C level, phosphorylation status, or cardiac morphology. Nonetheless, +/t mice show significantly decreased maximal force development at sarcomere lengths of 1.9 μm (+/t 68.5 ± 4.1 mN/mm(2) vs. +/+ 82.2 ± 3.2) and 2.3 μm (+/t 79.2 ± 3.1 mN/mm(2) vs. +/+ 95.5 ± 2.4). In addition, heterozygous mice show significant reductions in vivo in the early/after (E/A) (+/t 1.74 ± 0.12 vs. +/+ 2.58 ± 0.43) and E'/A' (+/t 1.18 ± 0.05 vs. +/+ 1.52 ± 0.15) ratios, indicating diastolic dysfunction. These results suggest that seemingly asymptomatic heterozygous MYBPC3 carriers do suffer impairments that may presage the onset of HCM.
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Affiliation(s)
- David Barefield
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois
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84
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Milani-Nejad N, Janssen PML. Small and large animal models in cardiac contraction research: advantages and disadvantages. Pharmacol Ther 2014; 141:235-49. [PMID: 24140081 PMCID: PMC3947198 DOI: 10.1016/j.pharmthera.2013.10.007] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 12/22/2022]
Abstract
The mammalian heart is responsible for not only pumping blood throughout the body but also adjusting this pumping activity quickly depending upon sudden changes in the metabolic demands of the body. For the most part, the human heart is capable of performing its duties without complications; however, throughout many decades of use, at some point this system encounters problems. Research into the heart's activities during healthy states and during adverse impacts that occur in disease states is necessary in order to strategize novel treatment options to ultimately prolong and improve patients' lives. Animal models are an important aspect of cardiac research where a variety of cardiac processes and therapeutic targets can be studied. However, there are differences between the heart of a human being and an animal and depending on the specific animal, these differences can become more pronounced and in certain cases limiting. There is no ideal animal model available for cardiac research, the use of each animal model is accompanied with its own set of advantages and disadvantages. In this review, we will discuss these advantages and disadvantages of commonly used laboratory animals including mouse, rat, rabbit, canine, swine, and sheep. Since the goal of cardiac research is to enhance our understanding of human health and disease and help improve clinical outcomes, we will also discuss the role of human cardiac tissue in cardiac research. This review will focus on the cardiac ventricular contractile and relaxation kinetics of humans and animal models in order to illustrate these differences.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA.
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85
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van Spaendonck-Zwarts KY, Posafalvi A, van den Berg MP, Hilfiker-Kleiner D, Bollen IAE, Sliwa K, Alders M, Almomani R, van Langen IM, van der Meer P, Sinke RJ, van der Velden J, Van Veldhuisen DJ, van Tintelen JP, Jongbloed JDH. Titin gene mutations are common in families with both peripartum cardiomyopathy and dilated cardiomyopathy. Eur Heart J 2014; 35:2165-73. [DOI: 10.1093/eurheartj/ehu050] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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86
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Cardiac myosin-binding protein-C is a critical mediator of diastolic function. Pflugers Arch 2014; 466:451-7. [PMID: 24442121 PMCID: PMC3928517 DOI: 10.1007/s00424-014-1442-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/23/2013] [Accepted: 01/03/2014] [Indexed: 12/25/2022]
Abstract
Diastolic dysfunction prominently contributes to heart failure with preserved ejection fraction (HFpEF). Owing partly to inadequate understanding, HFpEF does not have any effective treatments. Cardiac myosin-binding protein-C (cMyBP-C), a component of the thick filament of heart muscle that can modulate cross-bridge attachment/detachment cycling process by its phosphorylation status, appears to be involved in the diastolic dysfunction associated with HFpEF. In patients, cMyBP-C mutations are associated with diastolic dysfunction even in the absence of hypertrophy. cMyBP-C deletion mouse models recapitulate diastolic dysfunction despite in vitro evidence of uninhibited cross-bridge cycling. Reduced phosphorylation of cMyBP-C is also associated with diastolic dysfunction in patients. Mouse models of reduced cMyBP-C phosphorylation exhibit diastolic dysfunction while cMyBP-C phosphorylation mimetic mouse models show enhanced diastolic function. Thus, cMyBP-C phosphorylation mediates diastolic function. Experimental results of both cMyBP-C deletion and reduced cMyBP-C phosphorylation causing diastolic dysfunction suggest that cMyBP-C phosphorylation level modulates cross-bridge detachment rate in relation to ongoing attachment rate to mediate relaxation. Consequently, alteration in cMyBP-C regulation of cross-bridge detachment is a key mechanism that causes diastolic dysfunction. Regardless of the exact molecular mechanism, ample clinical and experimental data show that cMyBP-C is a critical mediator of diastolic function. Furthermore, targeting cMyBP-C phosphorylation holds potential as a future treatment for diastolic dysfunction.
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87
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Schlossarek S, Frey N, Carrier L. Ubiquitin-proteasome system and hereditary cardiomyopathies. J Mol Cell Cardiol 2013; 71:25-31. [PMID: 24380728 DOI: 10.1016/j.yjmcc.2013.12.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 11/13/2013] [Accepted: 12/17/2013] [Indexed: 12/14/2022]
Abstract
Adequate protein turnover is essential for cardiac homeostasis. Different protein quality controls are involved in the maintenance of protein homeostasis, including molecular chaperones and co-chaperones, the autophagy-lysosomal pathway, and the ubiquitin-proteasome system (UPS). In the last decade, a series of evidence has underlined a major function of the UPS in cardiac physiology and disease. Particularly, recent studies have shown that dysfunctional proteasomal function leads to cardiac disorders. Hypertrophic and dilated cardiomyopathies are the two most prevalent inherited cardiomyopathies. Both are primarily transmitted as an autosomal-dominant trait and mainly caused by mutations in genes encoding components of the cardiac sarcomere, including a relevant striated muscle-specific E3 ubiquitin ligase. A growing body of evidence indicates impairment of the UPS in inherited cardiomyopathies as determined by measurement of the level of ubiquitinated proteins, the activities of the proteasome and/or the use of fluorescent UPS reporter substrates. The present review will propose mechanisms of UPS impairment in inherited cardiomyopathies, summarize the potential consequences of UPS impairment, including activation of the unfolded protein response, and underline some therapeutic options available to restore proteasome function and therefore cardiac homeostasis and function. This article is part of a Special Issue entitled "Protein Quality Control, the Ubiquitin Proteasome System, and Autophagy".
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Affiliation(s)
- Saskia Schlossarek
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Norbert Frey
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany; Department of Cardiology and Angiology, University of Kiel, Kiel, Germany
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany; Inserm, U974, Paris F-75013, France; Université Pierre et Marie Curie- Paris 6, UM 76, CNRS, UMR 7215, Institut de Myologie, IFR14, Paris F-75013, France.
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88
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Behrens-Gawlik V, Mearini G, Gedicke-Hornung C, Richard P, Carrier L. MYBPC3 in hypertrophic cardiomyopathy: from mutation identification to RNA-based correction. Pflugers Arch 2013; 466:215-23. [PMID: 24337823 DOI: 10.1007/s00424-013-1409-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/18/2013] [Accepted: 11/22/2013] [Indexed: 01/16/2023]
Abstract
Mutations in MYBPC3 gene, encoding cardiac myosin-binding protein C (cMyBP-C), frequently cause hypertrophic cardiomyopathy (HCM), which affects 0.2 % of the general population. This myocardial autosomal-dominant disorder is the leading cause of sudden cardiac death particularly in young athletes. The current pharmacological and surgical treatments of HCM focus on symptoms relief, but do not address the cause of the disease. With the development of novel strategies targeting the endogenous mutation, causal HCM therapy is now possible. This review will discuss the current knowledge on HCM from the identification of MYBPC3 gene mutations to potential RNA-based correction.
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Affiliation(s)
- Verena Behrens-Gawlik
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
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89
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Güçlü A, Germans T, Witjas-Paalberends ER, Stienen GJM, Brouwer WP, Harms HJ, Marcus JT, Vonk ABA, Stooker W, Yilmaz A, Klein P, Ten Berg JM, Kluin J, Asselbergs FW, Lammertsma AA, Knaapen P, van Rossum AC, van der Velden J. ENerGetIcs in hypertrophic cardiomyopathy: traNslation between MRI, PET and cardiac myofilament function (ENGINE study). Neth Heart J 2013; 21:567-71. [PMID: 24114686 PMCID: PMC3833912 DOI: 10.1007/s12471-013-0478-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Introduction Hypertrophic cardiomyopathy (HCM) is an autosomal dominant heart disease mostly due to mutations in genes encoding sarcomeric proteins. HCM is characterised by asymmetric hypertrophy of the left ventricle (LV) in the absence of another cardiac or systemic disease. At present it lacks specific treatment to prevent or reverse cardiac dysfunction and hypertrophy in mutation carriers and HCM patients. Previous studies have indicated that sarcomere mutations increase energetic costs of cardiac contraction and cause myocardial dysfunction and hypertrophy. By using a translational approach, we aim to determine to what extent disturbances of myocardial energy metabolism underlie disease progression in HCM. Methods Hypertrophic obstructive cardiomyopathy (HOCM) patients and aortic valve stenosis (AVS) patients will undergo a positron emission tomography (PET) with acetate and cardiovascular magnetic resonance imaging (CMR) with tissue tagging before and 4 months after myectomy surgery or aortic valve replacement + septal biopsy. Myectomy tissue or septal biopsy will be used to determine efficiency of sarcomere contraction in-vitro, and results will be compared with in-vivo cardiac performance. Healthy subjects and non-hypertrophic HCM mutation carriers will serve as a control group. Endpoints Our study will reveal whether perturbations in cardiac energetics deteriorate during disease progression in HCM and whether these changes are attributed to cardiac remodelling or the presence of a sarcomere mutation per se. In-vitro studies in hypertrophied cardiac muscle from HOCM and AVS patients will establish whether sarcomere mutations increase ATP consumption of sarcomeres in human myocardium. Our follow-up imaging study in HOCM and AVS patients will reveal whether impaired cardiac energetics are restored by cardiac surgery.
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Affiliation(s)
- A Güçlü
- Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU, VU University Medical Center, ZH 5F-13, PO Box 7057, 1007MB, Amsterdam, the Netherlands,
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90
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Sequeira V, Witjas-Paalberends ER, Kuster DWD, van der Velden J. Cardiac myosin-binding protein C: hypertrophic cardiomyopathy mutations and structure-function relationships. Pflugers Arch 2013; 466:201-6. [PMID: 24240729 DOI: 10.1007/s00424-013-1400-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 10/30/2013] [Accepted: 10/31/2013] [Indexed: 01/05/2023]
Abstract
Cardiac myosin-binding protein C (cMyBP-C) research has been characterized by two waves. Initial interest was piqued by its discovery in 1973 as a contaminant of myosin preparations from skeletal muscle. The second wave started in 1995 by the discovery that mutations in the gene encoding cMyBP-C cause hypertrophic cardiomyopathy (HCM). In this review, we will address what is known of cMyBP-C's role as a regulator of contraction as well as its role in HCM.
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Affiliation(s)
- Vasco Sequeira
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands
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91
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van Dijk SJ, Boontje NM, Heymans MW, Ten Cate FJ, Michels M, Dos Remedios C, Dooijes D, van Slegtenhorst MA, van der Velden J, Stienen GJM. Preserved cross-bridge kinetics in human hypertrophic cardiomyopathy patients with MYBPC3 mutations. Pflugers Arch 2013; 466:1619-33. [PMID: 24186209 DOI: 10.1007/s00424-013-1391-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/04/2013] [Accepted: 10/19/2013] [Indexed: 12/23/2022]
Abstract
Mutations in the MYBPC3 gene, encoding cardiac myosin binding protein C (cMyBP-C) are frequent causes of hypertrophic cardiomyopathy (HCM). Previously, we have presented evidence for reduced cMyBP-C expression (haploinsufficiency), in patients with a truncation mutation in MYBPC3. In mice, lacking cMyBP-C cross-bridge kinetics was accelerated. In this study, we investigated whether cross-bridge kinetics was altered in myectomy samples from HCM patients harboring heterozygous MYBPC3 mutations (MYBPC3mut). Isometric force and the rate of force redevelopment (k tr) at different activating Ca(2+) concentrations were measured in mechanically isolated Triton-permeabilized cardiomyocytes from MYBPC3mut (n = 18) and donor (n = 7) tissue. Furthermore, the stretch activation response of cardiomyocytes was measured in tissue from eight MYBPC3mut patients and five donors to assess the rate of initial force relaxation (k 1) and the rate and magnitude of the transient increase in force (k 2 and P 3, respectively) after a rapid stretch. Maximal force development of the cardiomyocytes was reduced in MYBPC3mut (24.5 ± 2.3 kN/m(2)) compared to donor (34.9 ± 1.6 kN/m(2)). The rates of force redevelopment in MYBPC3mut and donor over a range of Ca(2+) concentrations were similar (k tr at maximal activation: 0.63 ± 0.03 and 0.75 ± 0.09 s(-1), respectively). Moreover, the stretch activation parameters did not differ significantly between MYBPC3mut and donor (k 1: 8.5±0.5 and 8.8 ± 0.4 s(-1); k 2: 0.77 ± 0.06 and 0.74 ± 0.09 s(-1); P 3: 0.08 ± 0.01 and 0.09 ± 0.01, respectively). Incubation with protein kinase A accelerated k 1 in MYBPC3mut and donor to a similar extent. Our experiments indicate that, at the cMyBP-C expression levels in this patient group (63 ± 6 % relative to donors), cross-bridge kinetics are preserved and that the depressed maximal force development is not explained by perturbation of cross-bridge kinetics.
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Affiliation(s)
- Sabine J van Dijk
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
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92
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MicroRNA transcriptome profiling in cardiac tissue of hypertrophic cardiomyopathy patients with MYBPC3 mutations. J Mol Cell Cardiol 2013; 65:59-66. [PMID: 24083979 DOI: 10.1016/j.yjmcc.2013.09.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 09/12/2013] [Accepted: 09/19/2013] [Indexed: 01/26/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is predominantly caused by mutations in genes encoding sarcomeric proteins. One of the most frequent affected genes is MYBPC3, which encodes the thick filament protein cardiac myosin binding protein C. Despite the prevalence of HCM, disease pathology and clinical outcome of sarcomeric mutations are largely unknown. We hypothesized that microRNAs (miRNAs) could play a role in the disease process. To determine which miRNAs were changed in expression, miRNA arrays were performed on heart tissue from HCM patients with a MYBPC3 mutation (n=6) and compared with hearts of non-failing donors (n=6). 532 out of 664 analyzed miRNAs were expressed in at least one heart sample. 13 miRNAs were differentially expressed in HCM compared with donors (at p<0.01, fold change ≥ 2). The genomic context of these differentially expressed miRNAs revealed that miR-204 (fold change 2.4 in HCM vs. donor) was located in an intron of the TRPM3 gene, encoding an aspecific cation channel involved in calcium entry. RT-PCR analysis revealed a trend towards TRPM3 upregulation in HCM compared with donor myocardium (fold change 2.3, p=0.078). In silico identification of mRNA targets of differentially expressed miRNAs showed a large proportion of genes involved in cardiac hypertrophy and cardiac beta-adrenergic receptor signaling and we showed reduced phosphorylation of cardiac troponin I in the HCM myocardium when compared with donor. HCM patients with MYBPC3 mutations have a specific miRNA expression profile. Downstream mRNA targets reveal possible involvement in cardiac signaling pathways.
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93
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Sequeira V, Nijenkamp LLAM, Regan JA, van der Velden J. The physiological role of cardiac cytoskeleton and its alterations in heart failure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:700-22. [PMID: 23860255 DOI: 10.1016/j.bbamem.2013.07.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac muscle cells are equipped with specialized biochemical machineries for the rapid generation of force and movement central to the work generated by the heart. During each heart beat cardiac muscle cells perceive and experience changes in length and load, which reflect one of the fundamental principles of physiology known as the Frank-Starling law of the heart. Cardiac muscle cells are unique mechanical stretch sensors that allow the heart to increase cardiac output, and adjust it to new physiological and pathological situations. In the present review we discuss the mechano-sensory role of the cytoskeletal proteins with respect to their tight interaction with the sarcolemma and extracellular matrix. The role of contractile thick and thin filament proteins, the elastic protein titin, and their anchorage at the Z-disc and M-band, with associated proteins are reviewed in physiologic and pathologic conditions leading to heart failure. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé
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Affiliation(s)
- Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Louise L A M Nijenkamp
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Jessica A Regan
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; Department of Physiology, Molecular Cardiovascular Research Program, Sarver Heart Center, University of Arizona, Tucson, AZ 85724, USA
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; ICIN-Netherlands Heart Institute, The Netherlands.
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94
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Gedicke-Hornung C, Behrens-Gawlik V, Reischmann S, Geertz B, Stimpel D, Weinberger F, Schlossarek S, Précigout G, Braren I, Eschenhagen T, Mearini G, Lorain S, Voit T, Dreyfus PA, Garcia L, Carrier L. Rescue of cardiomyopathy through U7snRNA-mediated exon skipping in Mybpc3-targeted knock-in mice. EMBO Mol Med 2013; 5:1128-45. [PMID: 23716398 PMCID: PMC3721478 DOI: 10.1002/emmm.201202168] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 04/19/2013] [Accepted: 04/19/2013] [Indexed: 11/26/2022] Open
Abstract
Exon skipping mediated by antisense oligoribonucleotides (AON) is a promising therapeutic approach for genetic disorders, but has not yet been evaluated for cardiac diseases. We investigated the feasibility and efficacy of viral-mediated AON transfer in a Mybpc3-targeted knock-in (KI) mouse model of hypertrophic cardiomyopathy (HCM). KI mice carry a homozygous G>A transition in exon 6, which results in three different aberrant mRNAs. We identified an alternative variant (Var-4) deleted of exons 5–6 in wild-type and KI mice. To enhance its expression and suppress aberrant mRNAs we designed AON-5 and AON-6 that mask splicing enhancer motifs in exons 5 and 6. AONs were inserted into modified U7 small nuclear RNA and packaged in adeno-associated virus (AAV-U7-AON-5+6). Transduction of cardiac myocytes or systemic administration of AAV-U7-AON-5+6 increased Var-4 mRNA/protein levels and reduced aberrant mRNAs. Injection of newborn KI mice abolished cardiac dysfunction and prevented left ventricular hypertrophy. Although the therapeutic effect was transient and therefore requires optimization to be maintained over an extended period, this proof-of-concept study paves the way towards a causal therapy of HCM.
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Affiliation(s)
- Christina Gedicke-Hornung
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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95
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Witjas-Paalberends ER, Piroddi N, Stam K, van Dijk SJ, Oliviera VS, Ferrara C, Scellini B, Hazebroek M, ten Cate FJ, van Slegtenhorst M, dos Remedios C, Niessen HWM, Tesi C, Stienen GJM, Heymans S, Michels M, Poggesi C, van der Velden J. Mutations in MYH7 reduce the force generating capacity of sarcomeres in human familial hypertrophic cardiomyopathy. Cardiovasc Res 2013; 99:432-41. [PMID: 23674513 DOI: 10.1093/cvr/cvt119] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Familial hypertrophic cardiomyopathy (HCM), frequently caused by sarcomeric gene mutations, is characterized by cellular dysfunction and asymmetric left-ventricular (LV) hypertrophy. We studied whether cellular dysfunction is due to an intrinsic sarcomere defect or cardiomyocyte remodelling. METHODS AND RESULTS Cardiac samples from 43 sarcomere mutation-positive patients (HCMmut: mutations in thick (MYBPC3, MYH7) and thin (TPM1, TNNI3, TNNT2) myofilament genes) were compared with 14 sarcomere mutation-negative patients (HCMsmn), eight patients with secondary LV hypertrophy due to aortic stenosis (LVHao) and 13 donors. Force measurements in single membrane-permeabilized cardiomyocytes revealed significantly lower maximal force generating capacity (Fmax) in HCMmut (21 ± 1 kN/m²) and HCMsmn (26 ± 3 kN/m²) compared with donor (36 ± 2 kN/m²). Cardiomyocyte remodelling was more severe in HCMmut compared with HCMsmn based on significantly lower myofibril density (49 ± 2 vs. 63 ± 5%) and significantly higher cardiomyocyte area (915 ± 15 vs. 612 ± 11 μm²). Low Fmax in MYBPC3mut, TNNI3mut, HCMsmn, and LVHao was normalized to donor values after correction for myofibril density. However, Fmax was significantly lower in MYH7mut, TPM1mut, and TNNT2mut even after correction for myofibril density. In accordance, measurements in single myofibrils showed very low Fmax in MYH7mut, TPM1mut, and TNNT2mut compared with donor (respectively, 73 ± 3, 70 ± 7, 83 ± 6, and 113 ± 5 kN/m²). In addition, force was lower in MYH7mut cardiomyocytes compared with MYBPC3mut, HCMsmn, and donor at submaximal [Ca²⁺]. CONCLUSION Low cardiomyocyte Fmax in HCM patients is largely explained by hypertrophy and reduced myofibril density. MYH7 mutations reduce force generating capacity of sarcomeres at maximal and submaximal [Ca²⁺]. These hypocontractile sarcomeres may represent the primary abnormality in patients with MYH7 mutations.
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Affiliation(s)
- E Rosalie Witjas-Paalberends
- Laboratory for Physiology, VU University Medical Center, Institute for Cardiovascular Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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96
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Cheng Y, Wan X, McElfresh TA, Chen X, Gresham KS, Rosenbaum DS, Chandler MP, Stelzer JE. Impaired contractile function due to decreased cardiac myosin binding protein C content in the sarcomere. Am J Physiol Heart Circ Physiol 2013; 305:H52-65. [PMID: 23666674 DOI: 10.1152/ajpheart.00929.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations in cardiac myosin binding protein C (MyBP-C) are a common cause of familial hypertrophic cardiomyopathy (FHC). The majority of MyBP-C mutations are expected to reduce MyBP-C expression; however, the consequences of MyBP-C deficiency on the regulation of myofilament function, Ca²⁺ homeostasis, and in vivo cardiac function are unknown. To elucidate the effects of decreased MyBP-C expression on cardiac function, we employed MyBP-C heterozygous null (MyBP-C+/-) mice presenting decreases in MyBP-C expression (32%) similar to those of FHC patients carrying MyBP-C mutations. The levels of MyBP-C phosphorylation were reduced 53% in MyBP-C+/- hearts compared with wild-type hearts. Skinned myocardium isolated from MyBP-C+/- hearts displayed decreased cross-bridge stiffness at half-maximal Ca²⁺ activations, increased steady-state force generation, and accelerated rates of cross-bridge recruitment at low Ca²⁺ activations (<15% and <25% of maximum, respectively). Protein kinase A treatment abolished basal differences in rates of cross-bridge recruitment between MyBP-C+/- and wild-type myocardium. Intact ventricular myocytes from MyBP-C+/- hearts displayed abnormal sarcomere shortening but unchanged Ca²⁺ transient kinetics. Despite a lack of left ventricular hypertrophy, MyBP-C+/- hearts exhibited elevated end-diastolic pressure and decreased peak rate of LV pressure rise, which was normalized following dobutamine infusion. Furthermore, electrocardiogram recordings in conscious MyBP-C+/- mice revealed prolonged QRS and QT intervals, which are known risk factors for cardiac arrhythmia. Collectively, our data show that reduced MyBP-C expression and phosphorylation in the sarcomere result in myofilament dysfunction, contributing to contractile dysfunction that precedes compensatory adaptations in Ca²⁺ handling, and chamber remodeling. Perturbations in mechanical and electrical activity in MyBP-C+/- mice could increase their susceptibility to cardiac dysfunction and arrhythmia.
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Affiliation(s)
- Y Cheng
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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97
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Impact of ANKRD1 mutations associated with hypertrophic cardiomyopathy on contraction parameters of engineered heart tissue. Basic Res Cardiol 2013; 108:349. [PMID: 23572067 DOI: 10.1007/s00395-013-0349-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/11/2013] [Accepted: 03/26/2013] [Indexed: 12/25/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a myocardial disease associated with mutations in sarcomeric genes. Three mutations were found in ANKRD1, encoding ankyrin repeat domain 1 (ANKRD1), a transcriptional co-factor located in the sarcomere. In the present study, we investigated whether expression of HCM-associated ANKRD1 mutations affects contraction parameters after gene transfer in engineered heart tissues (EHTs). EHTs were generated from neonatal rat heart cells and were transduced with adeno-associated virus encoding GFP or myc-tagged wild-type (WT) or mutant (P52A, T123M, or I280V) ANKRD1. Contraction parameters were analyzed from day 8 to day 16 of culture, and evaluated in the absence or presence of the proteasome inhibitor epoxomicin for 24 h. Under standard conditions, only WT- and T123M-ANKRD1 were correctly incorporated in the sarcomere. T123M-ANKRD1-transduced EHTs exhibited higher force and velocities of contraction and relaxation than WT- P52A- and I280V-ANKRD1 were highly unstable, not incorporated into the sarcomere, and did not induce contractile alterations. After epoxomicin treatment, P52A and I280V were both stabilized and incorporated into the sarcomere. I280V-transduced EHTs showed prolonged relaxation. These data suggest different impacts of ANKRD1 mutations on cardiomyocyte function: gain-of-function for T123M mutation under all conditions and dominant-negative effect for the I280V mutation which may come into play only when the proteasome is impaired.
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98
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Sequeira V, Wijnker PJM, Nijenkamp LLAM, Kuster DWD, Najafi A, Witjas-Paalberends ER, Regan JA, Boontje N, Ten Cate FJ, Germans T, Carrier L, Sadayappan S, van Slegtenhorst MA, Zaremba R, Foster DB, Murphy AM, Poggesi C, Dos Remedios C, Stienen GJM, Ho CY, Michels M, van der Velden J. Perturbed length-dependent activation in human hypertrophic cardiomyopathy with missense sarcomeric gene mutations. Circ Res 2013; 112:1491-505. [PMID: 23508784 DOI: 10.1161/circresaha.111.300436] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE High-myofilament Ca(2+) sensitivity has been proposed as a trigger of disease pathogenesis in familial hypertrophic cardiomyopathy (HCM) on the basis of in vitro and transgenic mice studies. However, myofilament Ca(2+) sensitivity depends on protein phosphorylation and muscle length, and at present, data in humans are scarce. OBJECTIVE To investigate whether high myofilament Ca(2+) sensitivity and perturbed length-dependent activation are characteristics for human HCM with mutations in thick and thin filament proteins. METHODS AND RESULTS Cardiac samples from patients with HCM harboring mutations in genes encoding thick (MYH7, MYBPC3) and thin (TNNT2, TNNI3, TPM1) filament proteins were compared with sarcomere mutation-negative HCM and nonfailing donors. Cardiomyocyte force measurements showed higher myofilament Ca(2+) sensitivity in all HCM samples and low phosphorylation of protein kinase A (PKA) targets compared with donors. After exogenous PKA treatment, myofilament Ca(2+) sensitivity was similar (MYBPC3mut, TPM1mut, sarcomere mutation-negative HCM), higher (MYH7mut, TNNT2mut), or even significantly lower (TNNI3mut) compared with donors. Length-dependent activation was significantly smaller in all HCM than in donor samples. PKA treatment increased phosphorylation of PKA-targets in HCM myocardium and normalized length-dependent activation to donor values in sarcomere mutation-negative HCM and HCM with truncating MYBPC3 mutations but not in HCM with missense mutations. Replacement of mutant by wild-type troponin in TNNT2mut and TNNI3mut corrected length-dependent activation to donor values. CONCLUSIONS High-myofilament Ca(2+) sensitivity is a common characteristic of human HCM and partly reflects hypophosphorylation of PKA targets compared with donors. Length-dependent sarcomere activation is perturbed by missense mutations, possibly via posttranslational modifications other than PKA hypophosphorylation or altered protein-protein interactions, and represents a common pathomechanism in HCM.
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Affiliation(s)
- Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, the Netherlands.
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Kraft T, Witjas-Paalberends ER, Boontje NM, Tripathi S, Brandis A, Montag J, Hodgkinson JL, Francino A, Navarro-Lopez F, Brenner B, Stienen GJM, van der Velden J. Familial hypertrophic cardiomyopathy: functional effects of myosin mutation R723G in cardiomyocytes. J Mol Cell Cardiol 2013; 57:13-22. [PMID: 23318932 DOI: 10.1016/j.yjmcc.2013.01.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 01/03/2013] [Indexed: 11/17/2022]
Abstract
Familial Hypertrophic Cardiomyopathy (FHC) is frequently caused by mutations in the β-cardiac myosin heavy chain (β-MyHC). To identify changes in sarcomeric function triggered by such mutations, distinguishing mutation effects from other functional alterations of the myocardium is essential. We previously identified a direct effect of mutation R723G (MyHC723) on myosin function in slow Musculus soleus fibers. Here we investigate contractile features of left ventricular cardiomyocytes of FHC-patients with the same MyHC723-mutation and compare these to the soleus data. In mechanically isolated, triton-permeabilized MyHC723-cardiomyocytes, maximum force was significantly lower but calcium-sensitivity was unchanged compared to donor. Conversely, MyHC723-soleus fibers showed significantly higher maximum force and reduced calcium-sensitivity compared to controls. Protein phosphorylation, a potential myocardium specific modifying mechanism, might account for differences compared to soleus fibers. Analysis revealed reduced phosphorylation of troponin I and T, myosin-binding-protein C, and myosin-light-chain 2 in MyHC723-myocardium compared to donor. Saturation of protein-kinaseA phospho-sites led to comparable, i.e., reduced MyHC723-calcium-sensitivity in cardiomyocytes as in M. soleus fibers, while maximum force remained reduced. Myofibrillar disarray and lower density of myofibrils, however, largely account for reduced maximum force in MyHC723-cardiomyocytes. The changes seen when phosphorylation of sarcomeric proteins in myocardium of affected patients is matched to control tissue suggest that the R723G mutation causes reduced Ca(++)-sensitivity in both cardiomyocytes and M. soleus fibers. In MyHC723-myocardium, however, hypophosphorylation can compensate for the reduced calcium-sensitivity, while maximum force generation, lowered by myofibrillar deficiency and disarray, remains impaired, and may only be compensated by hypertrophy.
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Affiliation(s)
- Theresia Kraft
- Molecular and Cell Physiology, Hannover Medical School, D-30625 Hannover, Germany.
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Hamdani N, Krysiak J, Kreusser MM, Neef S, Dos Remedios CG, Maier LS, Krüger M, Backs J, Linke WA. Crucial role for Ca2(+)/calmodulin-dependent protein kinase-II in regulating diastolic stress of normal and failing hearts via titin phosphorylation. Circ Res 2013; 112:664-74. [PMID: 23283722 DOI: 10.1161/circresaha.111.300105] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
RATIONALE Myocardial diastolic stiffness and cardiomyocyte passive force (F(passive)) depend in part on titin isoform composition and phosphorylation. Ca(2+)/calmodulin-dependent protein kinase-II (CaMKII) phosphorylates ion channels, Ca(2+)-handling proteins, and chromatin-modifying enzymes in the heart, but has not been known to target titin. OBJECTIVE To elucidate whether CaMKII phosphorylates titin and modulates F(passive) in normal and failing myocardium. METHODS AND RESULTS Titin phosphorylation was assessed in CaMKIIδ/γ double-knockout (DKO) mouse, transgenic CaMKIIδC-overexpressing mouse, and human hearts, by Pro-Q-Diamond/Sypro-Ruby staining, autoradiography, and immunoblotting using phosphoserine-specific titin-antibodies. CaMKII-dependent site-specific titin phosphorylation was quantified in vivo by mass spectrometry using stable isotope labeling by amino acids in cell culture mouse heart mixed with wild-type (WT) or DKO heart. F(passive) of single permeabilized cardiomyocytes was recorded before and after CaMKII-administration. All-titin phosphorylation was reduced by >50% in DKO but increased by up to ≈100% in transgenic versus WT hearts. Conserved CaMKII-dependent phosphosites were identified within the PEVK-domain of titin by quantitative mass spectrometry and confirmed in recombinant human PEVK-fragments. CaMKII also phosphorylated the cardiac titin N2B-unique sequence. Phosphorylation at specific PEVK/titin N2B-unique sequence sites was decreased in DKO and amplified in transgenic versus WT hearts. F(passive) was elevated in DKO and reduced in transgenic compared with WT cardiomyocytes. CaMKII-administration lowered F(passive) of WT and DKO cardiomyocytes, an effect blunted by titin antibody pretreatment. Human end-stage failing hearts revealed higher CaMKII expression/activity and phosphorylation at PEVK/titin N2B-unique sequence sites than nonfailing donor hearts. CONCLUSIONS CaMKII phosphorylates the titin springs at conserved serines/threonines, thereby lowering F(passive). Deranged CaMKII-dependent titin phosphorylation occurs in heart failure and contributes to altered diastolic stress.
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Affiliation(s)
- Nazha Hamdani
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
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