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Watanabe T, Kimura A, Kuroyanagi H. Alternative Splicing Regulator RBM20 and Cardiomyopathy. Front Mol Biosci 2018; 5:105. [PMID: 30547036 PMCID: PMC6279932 DOI: 10.3389/fmolb.2018.00105] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/09/2018] [Indexed: 12/17/2022] Open
Abstract
RBM20 is a vertebrate-specific RNA-binding protein with two zinc finger (ZnF) domains, one RNA-recognition motif (RRM)-type RNA-binding domain and an arginine/serine (RS)-rich region. RBM20 has initially been identified as one of dilated cardiomyopathy (DCM)-linked genes. RBM20 is a regulator of heart-specific alternative splicing and Rbm20ΔRRM mice lacking the RRM domain are defective in the splicing regulation. The Rbm20ΔRRM mice, however, do not exhibit a characteristic DCM-like phenotype such as dilatation of left ventricles or systolic dysfunction. Considering that most of the RBM20 mutations identified in familial DCM cases were heterozygous missense mutations in an arginine-serine-arginine-serine-proline (RSRSP) stretch whose phosphorylation is crucial for nuclear localization of RBM20, characterization of a knock-in animal model is awaited. One of the major targets for RBM20 is the TTN gene, which is comprised of the largest number of exons in mammals. Alternative splicing of the TTN gene is exceptionally complicated and RBM20 represses >160 of its consecutive exons, yet detailed mechanisms for such extraordinary regulation are to be elucidated. The TTN gene encodes the largest known protein titin, a multi-functional sarcomeric structural protein specific to striated muscles. As titin is the most important factor for passive tension of cardiomyocytes, extensive heart-specific and developmentally regulated alternative splicing of the TTN pre-mRNA by RBM20 plays a critical role in passive stiffness and diastolic function of the heart. In disease models with diastolic dysfunctions, the phenotypes were rescued by increasing titin compliance through manipulation of the Ttn pre-mRNA splicing, raising RBM20 as a potential therapeutic target.
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Affiliation(s)
- Takeshi Watanabe
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Department of Psychosomatic Dentistry, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Akinori Kimura
- Division of Pathology, Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Laboratory for Integrated Research Projects on Intractable Diseases Advanced Technology Laboratories, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Laboratory for Integrated Research Projects on Intractable Diseases Advanced Technology Laboratories, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States
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253
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Pott A, Shahid M, Köhler D, Pylatiuk C, Weinmann K, Just S, Rottbauer W. Therapeutic Chemical Screen Identifies Phosphatase Inhibitors to Reconstitute PKB Phosphorylation and Cardiac Contractility in ILK-Deficient Zebrafish. Biomolecules 2018; 8:biom8040153. [PMID: 30463267 PMCID: PMC6315389 DOI: 10.3390/biom8040153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/24/2018] [Accepted: 10/30/2018] [Indexed: 12/12/2022] Open
Abstract
Patients with inherited dilated cardiomyopathy (DCM) often suffer from severe heart failure based on impaired cardiac contractility leading to increased morbidity and mortality. Integrin-linked kinase (ILK) as a part of the cardiac mechanical stretch sensor was found to be an essential genetic regulator of cardiac contractility. Integrin-linked kinase localizes to z-disks and costameres in vertebrate hearts and regulates the activity of the signaling molecule protein kinase B (PKB/Akt) by controlling its phosphorylation. Despite identification of several potential drug targets in the ILK signaling pathway, pharmacological treatment strategies to restore contractile function in ILK-dependent cardiomyopathies have not been established yet. In recent years, the zebrafish has emerged as a valuable experimental system to model human cardiomyopathies as well as a powerful tool for the straightforward high-throughput in vivo small compound screening of therapeutically active substances. Using the ILK deficient zebrafish heart failure mutant main squeeze (msq), which shows reduced PKB phosphorylation and thereby impaired cardiac contractile force, we identified here, in an automated small compound screen, the protein phosphatase inhibitors calyculin A and okadaic acid significantly restoring myocardial contractile function by reconstituting PKB phosphorylation in msq ILK-deficient zebrafish embryos.
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Affiliation(s)
- Alexander Pott
- Department of Internal Medicine II, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - Maryam Shahid
- Department of Internal Medicine II, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - Doreen Köhler
- Department of Internal Medicine III, University of Heidelberg, D-69120 Heidelberg, Germany.
| | - Christian Pylatiuk
- Institute of Applied Computer Science, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany.
| | - Karolina Weinmann
- Department of Internal Medicine II, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - Steffen Just
- Department of Internal Medicine II, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - Wolfgang Rottbauer
- Department of Internal Medicine II, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
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254
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Rellini G, Piazza R, Loiudice E, Cassin M, Bernardi G, Pavan D, Cervesato E, Nicolosi GL. Heterogeneity of clinical presentation in Tako-Tsubo syndromes: the prevalence of normal segmental wall motion and normal ECG pattern. J Cardiovasc Med (Hagerstown) 2018; 19:717-724. [PMID: 30320724 DOI: 10.2459/jcm.0000000000000729] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
AIM The aim of this study is to report the heterogeneity of clinical presentation in Tako-Tsubo syndrome (TTS), including a significant prevalence of normal ECG and echocardiographic patterns in a series of consecutive patients from a single center. METHODS AND RESULTS From our database we selected a total of 168 cases of TTS. A total of 140 of these (Group A); 14 men (10%), mean age 60.3 years, range 39-87; 126 women (90%), mean age 66.1 years, range 43-93; matched the following reported criteria: typical stenocardic pain immediately following an emotional acute stress, or acute medical or surgical event within the preceding 12 h; acute rise and fall of troponin release; absence of significant coronary disease at coronary angiography. ECG findings at presentation ranged from T wave abnormalities (41 cases, 29.3%) to ST elevation (52 cases, 37.1%) and ST depression (11 cases, 7.9%), whereas in 36 cases (25.7%) the ECG was normal. Echocardiography at presentation showed akinesia of the total apical or medium-apical segments in 74 patients (53%), whereas it showed akinesia of left ventricular wall segments in other locations in 30 patients (21%) and even normal regional wall motion and thickening in 36 patients (26%). We described also a series of 13 female patients (mean age 70.2 years; age range 45-85 years) (Group B) who did not complain of chest pain at presentation, but showed a classical Tako-Tsubo evolution of wall motion abnormalities at echocardiography. Finally we selected 15 female patients (mean age 69.3 years; age range 49-89 years) (Group C) who formally did not report acute stress immediately preceding their presentation to the hospital for chest pain. They showed a classical Tako-Tsubo evolution of wall motion abnormalities at echocardiography and only one case of normal ECG pattern at presentation. CONCLUSION In this series of acute TTS, a wide variability of ECG and echocardiographic patterns are observed, ranging from ST elevation with coexisting segmental wall motion abnormalities of the typical TTS to a clinical presentation characterized by normal ECG and normal segmental wall motion pattern.
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Affiliation(s)
| | | | | | | | | | | | | | - Gian L Nicolosi
- Cardiology Department, ARC, Ospedale Civile.,Cardiology Clinic, Policlinico San Giorgio, Pordenone, Italy
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255
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Vikhorev PG, Vikhoreva NN. Cardiomyopathies and Related Changes in Contractility of Human Heart Muscle. Int J Mol Sci 2018; 19:ijms19082234. [PMID: 30065175 PMCID: PMC6121228 DOI: 10.3390/ijms19082234] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/22/2018] [Accepted: 07/27/2018] [Indexed: 02/07/2023] Open
Abstract
About half of hypertrophic and dilated cardiomyopathies cases have been recognized as genetic diseases with mutations in sarcomeric proteins. The sarcomeric proteins are involved in cardiomyocyte contractility and its regulation, and play a structural role. Mutations in non-sarcomeric proteins may induce changes in cell signaling pathways that modify contractile response of heart muscle. These facts strongly suggest that contractile dysfunction plays a central role in initiation and progression of cardiomyopathies. In fact, abnormalities in contractile mechanics of myofibrils have been discovered. However, it has not been revealed how these mutations increase risk for cardiomyopathy and cause the disease. Much research has been done and still much is being done to understand how the mechanism works. Here, we review the facts of cardiac myofilament contractility in patients with cardiomyopathy and heart failure.
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Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Natalia N Vikhoreva
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK.
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256
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Brodehl A, Gaertner-Rommel A, Milting H. Molecular insights into cardiomyopathies associated with desmin (DES) mutations. Biophys Rev 2018; 10:983-1006. [PMID: 29926427 DOI: 10.1007/s12551-018-0429-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 05/22/2018] [Indexed: 12/15/2022] Open
Abstract
Increasing usage of next-generation sequencing techniques pushed during the last decade cardiogenetic diagnostics leading to the identification of a huge number of genetic variants in about 170 genes associated with cardiomyopathies, channelopathies, or syndromes with cardiac involvement. Because of the biochemical and cellular complexity, it is challenging to understand the clinical meaning or even the relevant pathomechanisms of the majority of genetic sequence variants. However, detailed knowledge about the associated molecular pathomechanism is essential for the development of efficient therapeutic strategies in future and genetic counseling. Mutations in DES, encoding the muscle-specific intermediate filament protein desmin, have been identified in different kinds of cardiac and skeletal myopathies. Here, we review the functions of desmin in health and disease with a focus on cardiomyopathies. In addition, we will summarize the genetic and clinical literature about DES mutations and will explain relevant cell and animal models. Moreover, we discuss upcoming perspectives and consequences of novel experimental approaches like genome editing technology, which might open a novel research field contributing to the development of efficient and mutation-specific treatment options.
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Affiliation(s)
- Andreas Brodehl
- Erich and Hanna Klessmann Institute for Cardiovascular Research & Development, Heart and Diabetes Centre NRW, Ruhr-University Bochum, Georgstrasse 11, 32545, Bad Oeynhausen, Germany.
| | - Anna Gaertner-Rommel
- Erich and Hanna Klessmann Institute for Cardiovascular Research & Development, Heart and Diabetes Centre NRW, Ruhr-University Bochum, Georgstrasse 11, 32545, Bad Oeynhausen, Germany
| | - Hendrik Milting
- Erich and Hanna Klessmann Institute for Cardiovascular Research & Development, Heart and Diabetes Centre NRW, Ruhr-University Bochum, Georgstrasse 11, 32545, Bad Oeynhausen, Germany.
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257
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Merlo M, Porcari A, Sinagra G. The (ultra) sound of a burning heart: A matter of speckles. Int J Cardiol 2018; 259:132-133. [DOI: 10.1016/j.ijcard.2018.02.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 02/19/2018] [Indexed: 10/17/2022]
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258
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Limongelli G, Bossone E, Elliott PM, Day SM. On the Road from Gene to Therapy in Inherited Cardiomyopathies. Heart Fail Clin 2018. [DOI: 10.1016/j.hfc.2018.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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259
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260
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Rosales W, Lizcano F. The Histone Demethylase JMJD2A Modulates the Induction of Hypertrophy Markers in iPSC-Derived Cardiomyocytes. Front Genet 2018; 9:14. [PMID: 29479368 PMCID: PMC5811633 DOI: 10.3389/fgene.2018.00014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 01/10/2018] [Indexed: 01/04/2023] Open
Abstract
The development of cardiovascular pathologies is partly attributed to epigenetic causes, including histone methylation, which appears to be an important marker in hearts that develop cardiac hypertrophy. Previous studies showed that the histone demethylase JMJD2A can regulate the hypertrophic process in murine cardiomyocytes. However, the influence of JMJD2A on cardiac hypertrophy in a human cardiomyocyte model is still poorly understood. In the present study, cardiomyocytes derived from human induced pluripotent stem cells (iPSCs) were used. Hypertrophy was induced by angiotensin II and endothelin-1 (ET-1), and transfections were performed to overexpress JMJD2A and for small interfering RNA (siRNA)-induced silencing of JMJD2A. Gene expression analyses were determined using RT-PCR and Western blot. The expression levels of B-type natriuretic peptide (BNP), natriuretic peptide A (ANP), and beta myosin heavy chain (β-MHC) were increased by nearly 2–10-fold with ET-1 compared with the control. However, a higher level of JMJD2A and UTX was detected, whereas the level of JMJD2C was lower. When cardiomyocytes were transiently transfected with JMJD2A, an increase close to 150% in BNP was observed, and this increase was greater after treatment with ET-1. To verify the specificity of JMJD2A activity, a knockdown was performed by means of siRNA-JMJD2A, which led to a significant reduction in BNP. The involvement of JMJD2A suggests that histone-specific modifications are associated with genes encoding proteins that are actively transcribed during the hypertrophy process. Since BNP is closely related to JMJD2A expression, we suggest that there could be a direct influence of JMJD2A on the expression of BNP. These results may be studied further to reduce cardiac hypertrophy via the regulation of epigenetic modifiers.
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Affiliation(s)
- Wendy Rosales
- Center of Biomedical Research, Universidad de La Sabana, Chía, Colombia
| | - Fernando Lizcano
- Center of Biomedical Research, Universidad de La Sabana, Chía, Colombia
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261
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Chang ACY, Blau HM. Short telomeres - A hallmark of heritable cardiomyopathies. Differentiation 2018; 100:31-36. [PMID: 29482077 DOI: 10.1016/j.diff.2018.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 12/15/2022]
Abstract
Cardiovascular diseases are the leading cause of death worldwide and the incidence increases with age. Genetic testing has taught us much about the pathogenic pathways that drive heritable cardiomyopathies. Here we discuss an unexpected link between shortened telomeres, a molecular marker of aging, and genetic cardiomyopathy. Positioned at the ends of chromosomes, telomeres are DNA repeats which serve as protective caps that shorten with each cell division in proliferative tissues. Cardiomyocytes are an anomaly, as they are largely non-proliferative post-birth and retain relatively stable telomere lengths throughout life in healthy individuals. However, there is mounting evidence that in disease states, cardiomyocyte telomeres significantly shorten. Moreover, this shortening may play an active role in the development of mitochondrial dysfunction central to the etiology of dilated and hypertrophic cardiomyopathies. Elucidation of the mechanisms that underlie the telomere-mitochondrial signaling axis in the heart will provide fresh insights into our understanding of genetic cardiomyopathies, and could lead to the identification of previously uncharacterized modes of therapeutic intervention.
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Affiliation(s)
- Alex C Y Chang
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.
| | - Helen M Blau
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA.
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262
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Brophy JM. Big Data to Assess Potential Pregnancy-Related Cardiovascular Complications of Difficult Labour-Original Investigator-Driven Research Is Not Dead! Can J Cardiol 2017; 34:6-7. [PMID: 29275884 DOI: 10.1016/j.cjca.2017.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 12/28/2022] Open
Affiliation(s)
- James M Brophy
- Departments of Medicine and Epidemiology (McGill), Royal Victoria Hospital, Montreal, Quebec, Canada.
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263
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Affiliation(s)
- Gianfranco Sinagra
- From the Cardiovascular Department, Cardiomyopathy Centre, University of Trieste, Italy
| | - Matteo Dal Ferro
- From the Cardiovascular Department, Cardiomyopathy Centre, University of Trieste, Italy
| | - Marco Merlo
- From the Cardiovascular Department, Cardiomyopathy Centre, University of Trieste, Italy
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264
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Abstract
The nonischemic cardiomyopathies are a diverse group of cardiac disorders that frequently cause heart failure and death and are now recognized with increasing frequency. There has been substantial progress in the clinical recognition and understanding of the natural history of these conditions. Well-established and new techniques of cardiac imaging are also helpful in this regard. Basic scientists are elucidating the pathogenesis and pathobiology of individual cardiomyopathies. In this compendium, some of the most important advances in this field are reviewed. Scientific opportunities to enhance further collaborative research to accelerate progress are identified.
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Affiliation(s)
- Eugene Braunwald
- From the TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
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