1
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Mukhopadhyay S, Dixit P, Khanom N, Sanghera G, McGurk KA. The Genetic Factors Influencing Cardiomyopathies and Heart Failure across the Allele Frequency Spectrum. J Cardiovasc Transl Res 2024:10.1007/s12265-024-10520-y. [PMID: 38771459 DOI: 10.1007/s12265-024-10520-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 05/03/2024] [Indexed: 05/22/2024]
Abstract
Heart failure (HF) remains a major cause of mortality and morbidity worldwide. Understanding the genetic basis of HF allows for the development of disease-modifying therapies, more appropriate risk stratification, and personalised management of patients. The advent of next-generation sequencing has enabled genome-wide association studies; moving beyond rare variants identified in a Mendelian fashion and detecting common DNA variants associated with disease. We summarise the latest GWAS and rare variant data on mixed and refined HF aetiologies, and cardiomyopathies. We describe the recent understanding of the functional impact of titin variants and highlight FHOD3 as a novel cardiomyopathy-associated gene. We describe future directions of research in this field and how genetic data can be leveraged to improve the care of patients with HF.
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Affiliation(s)
- Srinjay Mukhopadhyay
- National Heart and Lung Institute, Imperial College London, LMS Building, Hammersmith Campus, London, UK
- School of Medicine, Cardiff University, Wales, UK
| | - Prithvi Dixit
- National Heart and Lung Institute, Imperial College London, LMS Building, Hammersmith Campus, London, UK
| | - Najiyah Khanom
- National Heart and Lung Institute, Imperial College London, LMS Building, Hammersmith Campus, London, UK
| | - Gianluca Sanghera
- National Heart and Lung Institute, Imperial College London, LMS Building, Hammersmith Campus, London, UK
| | - Kathryn A McGurk
- National Heart and Lung Institute, Imperial College London, LMS Building, Hammersmith Campus, London, UK.
- MRC Laboratory of Medical Sciences, Imperial College London, London, UK.
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2
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Ghahremani S, Kanwal A, Pettinato A, Ladha F, Legere N, Thakar K, Zhu Y, Tjong H, Wilderman A, Stump WT, Greenberg L, Greenberg MJ, Cotney J, Wei CL, Hinson JT. CRISPR Activation Reverses Haploinsufficiency and Functional Deficits Caused by TTN Truncation Variants. Circulation 2024; 149:1285-1297. [PMID: 38235591 PMCID: PMC11031707 DOI: 10.1161/circulationaha.123.063972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 12/13/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND TTN truncation variants (TTNtvs) are the most common genetic lesion identified in individuals with dilated cardiomyopathy, a disease with high morbidity and mortality rates. TTNtvs reduce normal TTN (titin) protein levels, produce truncated proteins, and impair sarcomere content and function. Therapeutics targeting TTNtvs have been elusive because of the immense size of TTN, the rarity of specific TTNtvs, and incomplete knowledge of TTNtv pathogenicity. METHODS We adapted CRISPR activation using dCas9-VPR to functionally interrogate TTNtv pathogenicity and develop a therapeutic in human cardiomyocytes and 3-dimensional cardiac microtissues engineered from induced pluripotent stem cell models harboring a dilated cardiomyopathy-associated TTNtv. We performed guide RNA screening with custom TTN reporter assays, agarose gel electrophoresis to quantify TTN protein levels and isoforms, and RNA sequencing to identify molecular consequences of TTN activation. Cardiomyocyte epigenetic assays were also used to nominate DNA regulatory elements to enable cardiomyocyte-specific TTN activation. RESULTS CRISPR activation of TTN using single guide RNAs targeting either the TTN promoter or regulatory elements in spatial proximity to the TTN promoter through 3-dimensional chromatin interactions rescued TTN protein deficits disturbed by TTNtvs. Increasing TTN protein levels normalized sarcomere content and contractile function despite increasing truncated TTN protein. In addition to TTN transcripts, CRISPR activation also increased levels of myofibril assembly-related and sarcomere-related transcripts. CONCLUSIONS TTN CRISPR activation rescued TTNtv-related functional deficits despite increasing truncated TTN levels, which provides evidence to support haploinsufficiency as a relevant genetic mechanism underlying heterozygous TTNtvs. CRISPR activation could be developed as a therapeutic to treat a large proportion of TTNtvs.
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Affiliation(s)
| | - Aditya Kanwal
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Anthony Pettinato
- Cardiology Center, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Feria Ladha
- Cardiology Center, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Nicholas Legere
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Ketan Thakar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Yanfen Zhu
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Harianto Tjong
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Andrea Wilderman
- Cardiology Center, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - W. Tom Stump
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lina Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael J. Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Justin Cotney
- Cardiology Center, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Chia-Lin Wei
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - J. Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
- Cardiology Center, University of Connecticut Health Center, Farmington, CT 06030, USA
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3
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Stroik D, Gregorich ZR, Raza F, Ge Y, Guo W. Titin: roles in cardiac function and diseases. Front Physiol 2024; 15:1385821. [PMID: 38660537 PMCID: PMC11040099 DOI: 10.3389/fphys.2024.1385821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The giant protein titin is an essential component of muscle sarcomeres. A single titin molecule spans half a sarcomere and mediates diverse functions along its length by virtue of its unique domains. The A-band of titin functions as a molecular blueprint that defines the length of the thick filaments, the I-band constitutes a molecular spring that determines cell-based passive stiffness, and various domains, including the Z-disk, I-band, and M-line, serve as scaffolds for stretch-sensing signaling pathways that mediate mechanotransduction. This review aims to discuss recent insights into titin's functional roles and their relationship to cardiac function. The role of titin in heart diseases, such as dilated cardiomyopathy and heart failure with preserved ejection fraction, as well as its potential as a therapeutic target, is also discussed.
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Affiliation(s)
- Dawson Stroik
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Zachery R. Gregorich
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Farhan Raza
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Ying Ge
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Wei Guo
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
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4
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Zhu P, Li J, Yan F, Islam S, Lin X, Xu X. Allelic heterogeneity of TTNtv dilated cardiomyopathy can be modeled in adult zebrafish. JCI Insight 2024; 9:e175501. [PMID: 38412038 PMCID: PMC11128207 DOI: 10.1172/jci.insight.175501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 02/21/2024] [Indexed: 02/29/2024] Open
Abstract
Allelic heterogeneity (AH) has been noted in truncational TTN-associated (TTNtv-associated) dilated cardiomyopathy (DCM); i.e., mutations affecting A-band-encoding exons are pathogenic, but those affecting Z-disc-encoding exons are likely benign. The lack of an in vivo animal model that recapitulates AH hinders the deciphering of the underlying mechanism. Here, we explored zebrafish as a candidate vertebrate model by phenotyping a collection of zebrafish ttntv alleles. We noted that cardiac function and sarcomere structure were more severely disrupted in ttntv-A than in ttntv-Z homozygous embryos. Consistently, cardiomyopathy-like phenotypes were present in ttntv-A but not ttntv-Z adult heterozygous mutants. The phenotypes observed in ttntv-A alleles were recapitulated in null mutants with the full titin-encoding sequences removed. Defective autophagic flux, largely due to impaired autophagosome-lysosome fusion, was also noted only in ttntv-A but not in ttntv-Z models. Moreover, we found that genetic manipulation of ulk1a restored autophagy flux and rescued cardiac dysfunction in ttntv-A animals. Together, our findings presented adult zebrafish as an in vivo animal model for studying AH in TTNtv DCM, demonstrated TTN loss of function is sufficient to trigger ttntv DCM in zebrafish, and uncovered ulk1a as a potential therapeutic target gene for TTNtv DCM.
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Affiliation(s)
- Ping Zhu
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Jiarong Li
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Cardiovascular Surgery, Second Xiangya Hospital, Central South University, Changsha, China
| | - Feixiang Yan
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Shahidul Islam
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
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5
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Hinson JT, Hershberger RE. Monoallelic TTN Truncation Variants Identified in Individuals With DCM May Cause a Mild Skeletal Myopathy. JACC. HEART FAILURE 2024; 12:754-756. [PMID: 38206233 DOI: 10.1016/j.jchf.2023.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 01/12/2024]
Affiliation(s)
- J Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA; Cardiology Center, UConn Health, Farmington, Connecticut, USA.
| | - Ray E Hershberger
- Divisions of Human Genetics and Cardiovascular Medicine, Department of Medicine, The Ohio State University Medical Center, Columbus, Ohio, USA; The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, USA
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6
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Pérez-Serra A, Toro R, Martinez-Barrios E, Iglesias A, Fernandez-Falgueras A, Alcalde M, Coll M, Puigmulé M, del Olmo B, Picó F, Lopez L, Arbelo E, Cesar S, de Llano CT, Mangas A, Brugada J, Sarquella-Brugada G, Brugada R, Campuzano O. Implementing a New Algorithm for Reinterpretation of Ambiguous Variants in Genetic Dilated Cardiomyopathy. Int J Mol Sci 2024; 25:3807. [PMID: 38612618 PMCID: PMC11012211 DOI: 10.3390/ijms25073807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/13/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Dilated cardiomyopathy is a heterogeneous entity that leads to heart failure and malignant arrhythmias. Nearly 50% of cases are inherited; therefore, genetic analysis is crucial to unravel the cause and for the early identification of carriers at risk. A large number of variants remain classified as ambiguous, impeding an actionable clinical translation. Our goal was to perform a comprehensive update of variants previously classified with an ambiguous role, applying a new algorithm of already available tools. In a cohort of 65 cases diagnosed with dilated cardiomyopathy, a total of 125 genetic variants were classified as ambiguous. Our reanalysis resulted in the reclassification of 12% of variants from an unknown to likely benign or likely pathogenic role, due to improved population frequencies. For all the remaining ambiguous variants, we used our algorithm; 60.9% showed a potential but not confirmed deleterious role, and 24.5% showed a potential benign role. Periodically updating the population frequencies is a cheap and fast action, making it possible to clarify the role of ambiguous variants. Here, we perform a comprehensive reanalysis to help to clarify the role of most of ambiguous variants. Our specific algorithms facilitate genetic interpretation in dilated cardiomyopathy.
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Affiliation(s)
- Alexandra Pérez-Serra
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Rocío Toro
- Medicine Department, School of Medicine, Cadiz University, 11003 Cadiz, Spain; (R.T.); (A.M.)
- Research Unit, Biomedical Research and Innovation Institute of Cadiz (INiBICA), Puerta del Mar University Hospital, 11009 Cadiz, Spain
| | - Estefanía Martinez-Barrios
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), 1105 AZ Amsterdam, The Netherlands; (E.M.-B.); (S.C.); (G.S.-B.)
- Pediatric Arrhythmias, Inherited Cardiac Diseases and Sudden Death Unit, Cardiology Department, Sant Joan de Déu Hospital de Barcelona, 08950 Barcelona, Spain
- Arrítmies Pediàtriques, Cardiologia Genètica i Mort Sobtada, Malalties Cardiovasculars en el Desenvolupament, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Anna Fernandez-Falgueras
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain;
| | - Mireia Alcalde
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Mónica Coll
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Marta Puigmulé
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Bernat del Olmo
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Ferran Picó
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Laura Lopez
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
| | - Elena Arbelo
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), 1105 AZ Amsterdam, The Netherlands; (E.M.-B.); (S.C.); (G.S.-B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Sergi Cesar
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), 1105 AZ Amsterdam, The Netherlands; (E.M.-B.); (S.C.); (G.S.-B.)
- Pediatric Arrhythmias, Inherited Cardiac Diseases and Sudden Death Unit, Cardiology Department, Sant Joan de Déu Hospital de Barcelona, 08950 Barcelona, Spain
- Arrítmies Pediàtriques, Cardiologia Genètica i Mort Sobtada, Malalties Cardiovasculars en el Desenvolupament, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain
| | - Coloma Tiron de Llano
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain;
| | - Alipio Mangas
- Medicine Department, School of Medicine, Cadiz University, 11003 Cadiz, Spain; (R.T.); (A.M.)
- Research Unit, Biomedical Research and Innovation Institute of Cadiz (INiBICA), Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Internal Medicine Department, Puerta del Mar University Hospital, School of Medicine, University of Cadiz, 11009 Cadiz, Spain
| | - Josep Brugada
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), 1105 AZ Amsterdam, The Netherlands; (E.M.-B.); (S.C.); (G.S.-B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Georgia Sarquella-Brugada
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), 1105 AZ Amsterdam, The Netherlands; (E.M.-B.); (S.C.); (G.S.-B.)
- Pediatric Arrhythmias, Inherited Cardiac Diseases and Sudden Death Unit, Cardiology Department, Sant Joan de Déu Hospital de Barcelona, 08950 Barcelona, Spain
- Arrítmies Pediàtriques, Cardiologia Genètica i Mort Sobtada, Malalties Cardiovasculars en el Desenvolupament, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain
- Medical Science Department, School of Medicine, University of Girona, 17003 Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain;
- Medical Science Department, School of Medicine, University of Girona, 17003 Girona, Spain
| | - Oscar Campuzano
- Cardiovascular Genetics Center, Institut d’Investigació Biomèdica de Girona (IDIBGI-CERCA), Parc Hospitalari Martí i Julià, Edifici M2, 17190 Salt, Spain; (A.P.-S.); (A.I.); (A.F.-F.); (M.A.); (M.C.); (M.P.); (B.d.O.); (F.P.); (L.L.)
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Medical Science Department, School of Medicine, University of Girona, 17003 Girona, Spain
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7
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Weston TGR, Rees M, Gautel M, Fraternali F. Walking with giants: The challenges of variant impact assessment in the giant sarcomeric protein titin. WIREs Mech Dis 2024; 16:e1638. [PMID: 38155593 DOI: 10.1002/wsbm.1638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/30/2023]
Abstract
Titin, the so-called "third filament" of the sarcomere, represents a difficult challenge for the determination of damaging genetic variants. A single titin molecule extends across half the length of a sarcomere in striated muscle, fulfilling a variety of vital structural and signaling roles, and has been linked to an equally varied range of myopathies, resulting in a significant burden on individuals and healthcare systems alike. While the consequences of truncating variants of titin are well-documented, the ramifications of the missense variants prevalent in the general population are less so. We here present a compendium of titin missense variants-those that result in a single amino-acid substitution in coding regions-reported to be pathogenic and discuss these in light of the nature of titin and the variant position within the sarcomere and their domain, the structural, pathological, and biophysical characteristics that define them, and the methods used for characterization. Finally, we discuss the current knowledge and integration of the multiple fields that have contributed to our understanding of titin-related pathology and offer suggestions as to how these concurrent methodologies may aid the further development in our understanding of titin and hopefully extend to other, less well-studied giant proteins. This article is categorized under: Cardiovascular Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Timir G R Weston
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK
| | - Martin Rees
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK
| | - Mathias Gautel
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK
| | - Franca Fraternali
- Institute of Structural and Molecular Biology, University College London, London, UK
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8
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Burnham HV, Cizauskas HE, Barefield DY. Fine tuning contractility: atrial sarcomere function in health and disease. Am J Physiol Heart Circ Physiol 2024; 326:H568-H583. [PMID: 38156887 PMCID: PMC11221815 DOI: 10.1152/ajpheart.00252.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
The molecular mechanisms of sarcomere proteins underlie the contractile function of the heart. Although our understanding of the sarcomere has grown tremendously, the focus has been on ventricular sarcomere isoforms due to the critical role of the ventricle in health and disease. However, atrial-specific or -enriched myofilament protein isoforms, as well as isoforms that become expressed in disease, provide insight into ways this complex molecular machine is fine-tuned. Here, we explore how atrial-enriched sarcomere protein composition modulates contractile function to fulfill the physiological requirements of atrial function. We review how atrial dysfunction negatively affects the ventricle and the many cardiovascular diseases that have atrial dysfunction as a comorbidity. We also cover the pathophysiology of mutations in atrial-enriched contractile proteins and how they can cause primary atrial myopathies. Finally, we explore what is known about contractile function in various forms of atrial fibrillation. The differences in atrial function in health and disease underscore the importance of better studying atrial contractility, especially as therapeutics currently in development to modulate cardiac contractility may have different effects on atrial sarcomere function.
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Affiliation(s)
- Hope V Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| | - Hannah E Cizauskas
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| | - David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
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9
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DePaolo J, Bornstein M, Judy R, Abramowitz S, Verma SS, Levin MG, Arany Z, Damrauer SM. Titin-Truncating variants Predispose to Dilated Cardiomyopathy in Diverse Populations. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.17.24301405. [PMID: 38293092 PMCID: PMC10827233 DOI: 10.1101/2024.01.17.24301405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Importance The effect of high percentage spliced in (hiPSI) TTN truncating variants (TTNtvs) on risk of dilated cardiomyopathy (DCM) has historically been studied among population subgroups defined by genetic similarity to European reference populations. This has raised questions about the effect of TTNtvs in diverse populations, especially among individuals genetically similar to African reference populations. Objective To determine the effect of TTNtvs on risk of DCM in diverse population as measured by genetic distance (GD) in principal component (PC) space. Design Cohort study. Setting Penn Medicine Biobank (PMBB) is a large, diverse biobank. Participants Participants were recruited from across the Penn Medicine healthcare system and volunteered to have their electronic health records linked to biospecimen data including DNA which has undergone whole exome sequencing. Main Outcomes and Measures Risk of DCM among individuals carrying a hiPSI TTNtv. Results Carrying a hiPSI TTNtv was associated with DCM among PMBB participants across a range of GD deciles from the 1000G European centroid; the effect estimates ranged from odds ratio (OR) = 3.29 (95% confidence interval [CI] 1.26 to 8.56) to OR = 9.39 (95% CI 3.82 to 23.13). When individuals were assigned to population subgroups based on genetic similarity to the 1000G reference populations, hiPSI TTNtvs conferred significant risk of DCM among those genetically similar to the 1000G European reference population (OR = 7.55, 95% CI 4.99 to 11.42, P<0.001) and individuals genetically similar to the 1000G African reference population (OR 3.50, 95% CI 1.48 to 8.24, P=0.004). Conclusions and Relevance TTNtvs are associated with increased risk of DCM among a diverse cohort. There is no significant difference in effect of TTNtvs on DCM risk across deciles of GD from the 1000G European centroid, suggesting genetic background should not be considered when screening individuals for titin-related DCM.
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Affiliation(s)
- John DePaolo
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marc Bornstein
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Renae Judy
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarah Abramowitz
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shefali S Verma
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Michael G Levin
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA 19104, USA
| | - Zoltan Arany
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Scott M Damrauer
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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10
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Hinson JT, Campbell SG. TTN truncation variants produce sarcomere-integrating proteins of uncertain functional significance. J Clin Invest 2024; 134:e175206. [PMID: 38226618 PMCID: PMC10786689 DOI: 10.1172/jci175206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024] Open
Abstract
Titin (TTN) is one of the largest and most complex proteins expressed in humans, and truncation variants are the most prevalent genetic lesion identified in individuals with dilated cardiomyopathy (DCM) or other disorders of impaired cardiac contractility. Two reports in this issue of the JCI shed light on a potential mechanism involving truncated TTN sarcomere integration and the potential for disruption of sarcomere structural integrity. Kellermayer, Tordai, and colleagues confirmed the presence of truncated TTN protein in human DCM samples. McAfee and authors developed a patient-specific TTN antibody to study truncated TTN subcellular localization and to explore its functional consequences. A "poison peptide" mechanism emerges that inspires alternative therapeutic approaches while opening new lines for inquiry, such as the role of haploinsufficiency of full-length TTN protein, mechanisms explaining sarcomere dysfunction, and explanations for variable penetrance.
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Affiliation(s)
- J. Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA
- Cardiology Center, UConn Health, Farmington, Connecticut, USA
| | - Stuart G. Campbell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
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11
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Kellermayer D, Tordai H, Kiss B, Török G, Péter DM, Sayour AA, Pólos M, Hartyánszky I, Szilveszter B, Labeit S, Gángó A, Bedics G, Bödör C, Radovits T, Merkely B, Kellermayer MS. Truncated titin is structurally integrated into the human dilated cardiomyopathic sarcomere. J Clin Invest 2024; 134:e169753. [PMID: 37962957 PMCID: PMC10763722 DOI: 10.1172/jci169753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/08/2023] [Indexed: 11/16/2023] Open
Abstract
Heterozygous (HET) truncating variant mutations in the TTN gene (TTNtvs), encoding the giant titin protein, are the most common genetic cause of dilated cardiomyopathy (DCM). However, the molecular mechanisms by which TTNtv mutations induce DCM are controversial. Here, we studied 127 clinically identified DCM human cardiac samples with next-generation sequencing (NGS), high-resolution gel electrophoresis, Western blot analysis, and super-resolution microscopy in order to dissect the structural and functional consequences of TTNtv mutations. The occurrence of TTNtv was found to be 15% in the DCM cohort. Truncated titin proteins matching, by molecular weight, the gene sequence predictions were detected in the majority of the TTNtv+ samples. Full-length titin was reduced in TTNtv+ compared with TTNtv- samples. Proteomics analysis of washed myofibrils and stimulated emission depletion (STED) super-resolution microscopy of myocardial sarcomeres labeled with sequence-specific anti-titin antibodies revealed that truncated titin was structurally integrated into the sarcomere. Sarcomere length-dependent anti-titin epitope position, shape, and intensity analyses pointed at possible structural defects in the I/A junction and the M-band of TTNtv+ sarcomeres, which probably contribute, possibly via faulty mechanosensor function, to the development of manifest DCM.
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Affiliation(s)
- Dalma Kellermayer
- Heart and Vascular Center
- Department of Biophysics and Radiation Biology, and
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | | | - Balázs Kiss
- Department of Biophysics and Radiation Biology, and
| | - György Török
- Department of Biophysics and Radiation Biology, and
| | | | | | | | | | | | - Siegfried Labeit
- DZHK Partnersite Mannheim-Heidelberg, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ambrus Gángó
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Gábor Bedics
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Csaba Bödör
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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12
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McAfee Q, Caporizzo MA, Uchida K, Bedi KC, Margulies KB, Arany Z, Prosser BL. Truncated titin protein in dilated cardiomyopathy incorporates into the sarcomere and transmits force. J Clin Invest 2024; 134:e170196. [PMID: 37943622 PMCID: PMC10786684 DOI: 10.1172/jci170196] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Affiliation(s)
| | - Matthew A. Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Keita Uchida
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | | | - Zolt Arany
- Cardiovascular Institute, Department of Medicine and
| | - Benjamin L. Prosser
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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13
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Arany Z. Peripartum Cardiomyopathy. N Engl J Med 2024; 390:154-164. [PMID: 38197818 DOI: 10.1056/nejmra2306667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Affiliation(s)
- Zoltan Arany
- From the Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia
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14
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Levin MG, Aragam KG. Truncations of Titin and Left Atrial Cardiomyopathy: Comment on Henkens et al.'s article, Left Atrial Function in Patients With Titin Cardiomyopathy. J Card Fail 2024; 30:61-63. [PMID: 37451603 DOI: 10.1016/j.cardfail.2023.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 06/16/2023] [Indexed: 07/18/2023]
Affiliation(s)
- Michael G Levin
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA.
| | - Krishna G Aragam
- Massachusetts General Hospital and Harvard Medical School, Boston, MA; Broad Institute of MIT and Harvard, Cambridge, MA.
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15
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Henkens MTHM, Raafs AG, Vanloon T, Vos JL, Vandenwijngaard A, Brunner HG, Krapels IPC, Knackstedt C, Gerretsen S, Hazebroek MR, Vernooy K, Nijveldt R, Lumens J, Verdonschot JAJ. Left Atrial Function in Patients with Titin Cardiomyopathy. J Card Fail 2024; 30:51-60. [PMID: 37230314 DOI: 10.1016/j.cardfail.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 05/01/2023] [Accepted: 05/01/2023] [Indexed: 05/27/2023]
Abstract
BACKGROUND Truncating variants in titin (TTNtv) are the most prevalent genetic etiology of dilated cardiomyopathy (DCM). Although TTNtv has been associated with atrial fibrillation, it remains unknown whether and how left atrial (LA) function differs between patients with DCM with and without TTNtv. We aimed to determine and compare LA function in patients with DCM with and without TTNtv and to evaluate whether and how left ventricular (LV) function affects the LA using computational modeling. METHODS AND RESULTS Patients with DCM from the Maastricht DCM registry that underwent genetic testing and cardiovascular magnetic resonance (CMR) were included in the current study. Subsequent computational modeling (CircAdapt model) was performed to identify potential LV and LA myocardial hemodynamic substrates. In total, 377 patients with DCM (n = 42 with TTNtv, n = 335 without a genetic variant) were included (median age 55 years, interquartile range [IQR] 46-62 years, 62% men). Patients with TTNtv had a larger LA volume and decreased LA strain compared with patients without a genetic variant (LA volume index 60 mLm-2 [IQR 49-83] vs 51 mLm-2 [IQR 42-64]; LA reservoir strain 24% [IQR 10-29] vs 28% [IQR 20-34]; LA booster strain 9% [IQR 4-14] vs 14% [IQR 10-17], respectively; all P < .01). Computational modeling suggests that while the observed LV dysfunction partially explains the observed LA dysfunction in the patients with TTNtv, both intrinsic LV and LA dysfunction are present in patients with and without a TTNtv. CONCLUSIONS Patients with DCM with TTNtv have more severe LA dysfunction compared with patients without a genetic variant. Insights from computational modeling suggest that both intrinsic LV and LA dysfunction are present in patients with DCM with and without TTNtv.
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Affiliation(s)
- Michiel T H M Henkens
- Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands; Centre for Heart Failure Research, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, the Netherlands; Netherlands Heart Institute (NLHI), Utrecht, the Netherlands
| | - Anne G Raafs
- Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands; Centre for Heart Failure Research, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, the Netherlands
| | - Tim Vanloon
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the Netherlands
| | - Jacqueline L Vos
- Department of Cardiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Arthur Vandenwijngaard
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Han G Brunner
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands; GROW Institute for Developmental Biology and Cancer, Maastricht University, Maastricht, the Netherlands; Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ingrid P C Krapels
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Christian Knackstedt
- Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands; Centre for Heart Failure Research, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, the Netherlands
| | - Suzanne Gerretsen
- Department of Radiology and Nuclear Medicine, Cardiovascular research Institute Maastricht (CARIM), Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Mark R Hazebroek
- Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Kevin Vernooy
- Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands; Centre for Heart Failure Research, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, the Netherlands
| | - Robin Nijveldt
- Department of Cardiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joost Lumens
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the Netherlands
| | - Job A J Verdonschot
- Centre for Heart Failure Research, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, the Netherlands; Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands.
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16
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Martinez-Martin I, Crousilles A, Ochoa JP, Velazquez-Carreras D, Mortensen SA, Herrero-Galan E, Delgado J, Dominguez F, Garcia-Pavia P, de Sancho D, Wilmanns M, Alegre-Cebollada J. Titin domains with reduced core hydrophobicity cause dilated cardiomyopathy. Cell Rep 2023; 42:113490. [PMID: 38052212 DOI: 10.1016/j.celrep.2023.113490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 12/07/2023] Open
Abstract
The underlying genetic defect in most cases of dilated cardiomyopathy (DCM), a common inherited heart disease, remains unknown. Intriguingly, many patients carry single missense variants of uncertain pathogenicity targeting the giant protein titin, a fundamental sarcomere component. To explore the deleterious potential of these variants, we first solved the wild-type and mutant crystal structures of I21, the titin domain targeted by pathogenic variant p.C3575S. Although both structures are remarkably similar, the reduced hydrophobicity of deeply buried position 3575 strongly destabilizes the mutant domain, a scenario supported by molecular dynamics simulations and by biochemical assays that show no disulfide involving C3575. Prompted by these observations, we have found that thousands of similar hydrophobicity-reducing variants associate specifically with DCM. Hence, our results imply that titin domain destabilization causes DCM, a conceptual framework that not only informs pathogenicity assessment of gene variants but also points to therapeutic strategies counterbalancing protein destabilization.
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Affiliation(s)
- Ines Martinez-Martin
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain.
| | - Audrey Crousilles
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
| | - Juan Pablo Ochoa
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHIM, CIBERCV, 28222 Madrid, Spain; Health in Code, 15008 A Coruña, Spain
| | | | - Simon A Mortensen
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
| | - Elias Herrero-Galan
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Javier Delgado
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Fernando Dominguez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHIM, CIBERCV, 28222 Madrid, Spain
| | - Pablo Garcia-Pavia
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHIM, CIBERCV, 28222 Madrid, Spain
| | - David de Sancho
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia, Kimika Fakultatea, UPV/EHU, 20018 Donostia-San Sebastian, Euskadi, Spain; Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastian, Euskadi, Spain
| | - Matthias Wilmanns
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
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17
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Wang S, Zhang Z, He J, Liu J, Guo X, Chu H, Xu H, Wang Y. Comprehensive review on gene mutations contributing to dilated cardiomyopathy. Front Cardiovasc Med 2023; 10:1296389. [PMID: 38107262 PMCID: PMC10722203 DOI: 10.3389/fcvm.2023.1296389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is one of the most common primary myocardial diseases. However, to this day, it remains an enigmatic cardiovascular disease (CVD) characterized by ventricular dilatation, which leads to myocardial contractile dysfunction. It is the most common cause of chronic congestive heart failure and the most frequent indication for heart transplantation in young individuals. Genetics and various other factors play significant roles in the progression of dilated cardiomyopathy, and variants in more than 50 genes have been associated with the disease. However, the etiology of a large number of cases remains elusive. Numerous studies have been conducted on the genetic causes of dilated cardiomyopathy. These genetic studies suggest that mutations in genes for fibronectin, cytoskeletal proteins, and myosin in cardiomyocytes play a key role in the development of DCM. In this review, we provide a comprehensive description of the genetic basis, mechanisms, and research advances in genes that have been strongly associated with DCM based on evidence-based medicine. We also emphasize the important role of gene sequencing in therapy for potential early diagnosis and improved clinical management of DCM.
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Affiliation(s)
- Shipeng Wang
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
| | - Zhiyu Zhang
- Department of Cardiovascular Medicine, The Second People's Hospital of Yibin, Yibin, China
| | - Jiahuan He
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
| | - Junqian Liu
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
| | - Xia Guo
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
| | - Haoxuan Chu
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
| | - Hanchi Xu
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
| | - Yushi Wang
- Department of Cardiovascular Medicine, The First Hospital of Jilin University, Changchun, China
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18
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Jacobs J, Van Aelst L, Breckpot J, Corveleyn A, Kuiperi C, Dupont M, Heggermont W, De Vadder K, Willems R, Van Cleemput J, Bogaert JG, Robyns T. Tools to differentiate between Filamin C and Titin truncating variant carriers: value of MRI. Eur J Hum Genet 2023; 31:1323-1332. [PMID: 37032351 PMCID: PMC10620392 DOI: 10.1038/s41431-023-01357-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/01/2023] [Accepted: 03/22/2023] [Indexed: 04/11/2023] Open
Abstract
Whereas truncating variants of the giant protein Titin (TTNtv) are the main cause of familial dilated cardiomyopathy (DCM), recently Filamin C truncating variants (FLNCtv) were identified as a cause of arrhythmogenic cardiomyopathy (ACM). Our aim was to characterize and compare clinical and MRI features of TTNtv and FLNCtv in the Belgian population. In index patients referred for genetic testing of ACM/DCM, FLNCtv and TTNtv were found in 17 (3.6%) and 33 (12.3%) subjects, respectively. Further family cascade screening yielded 24 and 19 additional truncating variant carriers in FLNC and TTN, respectively. The main phenotype was ACM in FLNCtv carriers whereas TTNtv carriers showed either an ACM or DCM phenotype. Non-sustained Ventricular Tachycardia was frequent in both populations. MRI data, available in 28/40 FLNCtv and 32/52 TTNtv patients, showed lower Left Ventricular (LV) ejection fraction and lower LV strain in TTNtv patients (p < 0.01). Conversely, both the frequency (68% vs 22%) and extent of non-ischemic myocardial late gadolinium enhancement (LGE) was significantly higher in FLNCtv patients (p < 0.01). Hereby, ring-like LGE was found in 16/19 (84%) FLNCtv versus 1/7 (14%) of TTNtv patients (p < 0.01). In conclusion, a large number of FLNCtv and TTNtv patients present with an ACM phenotype but can be separated by cardiac MRI. Whereas FLNCtv patients often have extensive myocardial fibrosis, typically following a ring-like pattern, LV dysfunction without or limited replacement fibrosis is the common TTNtv phenotype.
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Affiliation(s)
- Johanna Jacobs
- Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium.
- Department of Cardiovascular Diseases, University Hospitals Leuven, 3000, Leuven, Belgium.
| | - Lucas Van Aelst
- Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium
- Department of Cardiovascular Diseases, University Hospitals Leuven, 3000, Leuven, Belgium
| | | | | | - Cuno Kuiperi
- Center for Human Genetics, UZ Leuven, 3000, Leuven, Belgium
| | - Matthias Dupont
- Department of Cardiology, Ziekenhuis Oost-Limburg (ZOL), 3600, Genk, Belgium
| | - Ward Heggermont
- Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium
- Department of Cardiology, Onze-Lieve-Vrouwziekenhuis Aalst, 9300, Aalst, Belgium
| | | | - Rik Willems
- Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium
- Department of Cardiovascular Diseases, University Hospitals Leuven, 3000, Leuven, Belgium
| | - Johan Van Cleemput
- Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium
- Department of Cardiovascular Diseases, University Hospitals Leuven, 3000, Leuven, Belgium
| | - Jan G Bogaert
- Department of Radiology, UZ Leuven, 3000, Leuven, Belgium
- Department of Imaging and Pathology, KU Leuven, 3000, Leuven, Belgium
| | - Tomas Robyns
- Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium
- Department of Cardiovascular Diseases, University Hospitals Leuven, 3000, Leuven, Belgium
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19
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McGurk KA, Zhang X, Theotokis P, Thomson K, Harper A, Buchan RJ, Mazaika E, Ormondroyd E, Wright WT, Macaya D, Pua CJ, Funke B, MacArthur DG, Prasad SK, Cook SA, Allouba M, Aguib Y, Yacoub MH, O'Regan DP, Barton PJR, Watkins H, Bottolo L, Ware JS. The penetrance of rare variants in cardiomyopathy-associated genes: A cross-sectional approach to estimating penetrance for secondary findings. Am J Hum Genet 2023; 110:1482-1495. [PMID: 37652022 PMCID: PMC10502871 DOI: 10.1016/j.ajhg.2023.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/21/2023] [Accepted: 08/04/2023] [Indexed: 09/02/2023] Open
Abstract
Understanding the penetrance of pathogenic variants identified as secondary findings (SFs) is of paramount importance with the growing availability of genetic testing. We estimated penetrance through large-scale analyses of individuals referred for diagnostic sequencing for hypertrophic cardiomyopathy (HCM; 10,400 affected individuals, 1,332 variants) and dilated cardiomyopathy (DCM; 2,564 affected individuals, 663 variants), using a cross-sectional approach comparing allele frequencies against reference populations (293,226 participants from UK Biobank and gnomAD). We generated updated prevalence estimates for HCM (1:543) and DCM (1:220). In aggregate, the penetrance by late adulthood of rare, pathogenic variants (23% for HCM, 35% for DCM) and likely pathogenic variants (7% for HCM, 10% for DCM) was substantial for dominant cardiomyopathy (CM). Penetrance was significantly higher for variant subgroups annotated as loss of function or ultra-rare and for males compared to females for variants in HCM-associated genes. We estimated variant-specific penetrance for 316 recurrent variants most likely to be identified as SFs (found in 51% of HCM- and 17% of DCM-affected individuals). 49 variants were observed at least ten times (14% of affected individuals) in HCM-associated genes. Median penetrance was 14.6% (±14.4% SD). We explore estimates of penetrance by age, sex, and ancestry and simulate the impact of including future cohorts. This dataset reports penetrance of individual variants at scale and will inform the management of individuals undergoing genetic screening for SFs. While most variants had low penetrance and the costs and harms of screening are unclear, some individuals with highly penetrant variants may benefit from SFs.
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Affiliation(s)
- Kathryn A McGurk
- National Heart and Lung Institute, Imperial College London, London, UK; MRC London Institute of Medical Sciences, Imperial College London, London, UK
| | - Xiaolei Zhang
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Pantazis Theotokis
- National Heart and Lung Institute, Imperial College London, London, UK; MRC London Institute of Medical Sciences, Imperial College London, London, UK
| | - Kate Thomson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and the Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Andrew Harper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and the Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Rachel J Buchan
- National Heart and Lung Institute, Imperial College London, London, UK; MRC London Institute of Medical Sciences, Imperial College London, London, UK; Royal Brompton & Harefield Hospitals, Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - Erica Mazaika
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Elizabeth Ormondroyd
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and the Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - William T Wright
- Northern Ireland Regional Genetics Centre, Belfast Health and Social Care Trust, Belfast City Hospital, Belfast, Northern Ireland, UK
| | | | - Chee Jian Pua
- National Heart Research Institute Singapore and Duke-National University of Singapore, Singapore, Singapore
| | - Birgit Funke
- Laboratory for Molecular Medicine, Partners Healthcare Center for Personalized Genetic Medicine, Boston, MA, USA
| | - Daniel G MacArthur
- Centre for Population Genomics, Garvan Institute of Medical Research and UNSW, Sydney, NSW, Australia; Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Sanjay K Prasad
- National Heart and Lung Institute, Imperial College London, London, UK; Royal Brompton & Harefield Hospitals, Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - Stuart A Cook
- MRC London Institute of Medical Sciences, Imperial College London, London, UK; National Heart Research Institute Singapore and Duke-National University of Singapore, Singapore, Singapore
| | - Mona Allouba
- National Heart and Lung Institute, Imperial College London, London, UK; Aswan Heart Centre, Aswan, Egypt
| | - Yasmine Aguib
- National Heart and Lung Institute, Imperial College London, London, UK; Aswan Heart Centre, Aswan, Egypt
| | - Magdi H Yacoub
- National Heart and Lung Institute, Imperial College London, London, UK; Royal Brompton & Harefield Hospitals, Guy's and St. Thomas' NHS Foundation Trust, London, UK; Aswan Heart Centre, Aswan, Egypt
| | - Declan P O'Regan
- MRC London Institute of Medical Sciences, Imperial College London, London, UK
| | - Paul J R Barton
- National Heart and Lung Institute, Imperial College London, London, UK; MRC London Institute of Medical Sciences, Imperial College London, London, UK; Royal Brompton & Harefield Hospitals, Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and the Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Leonardo Bottolo
- Department of Medical Genetics, University of Cambridge, Cambridge, UK; The Alan Turing Institute, London, UK; MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - James S Ware
- National Heart and Lung Institute, Imperial College London, London, UK; MRC London Institute of Medical Sciences, Imperial College London, London, UK; Royal Brompton & Harefield Hospitals, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
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20
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Baban A, Cicenia M, Magliozzi M, Parlapiano G, Cirillo M, Pascolini G, Fattori F, Gnazzo M, Bruno P, De Luca L, Di Chiara L, Francalanci P, Udd B, Secinaro A, Amodeo A, Bertini ES, Savarese M, Drago F, Novelli A. Biallelic truncating variants in children with titinopathy represent a recognizable condition with distinctive muscular and cardiac characteristics: a report on five patients. Front Cardiovasc Med 2023; 10:1210378. [PMID: 37576110 PMCID: PMC10415037 DOI: 10.3389/fcvm.2023.1210378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 07/10/2023] [Indexed: 08/15/2023] Open
Abstract
Background Monoallelic and biallelic TTN truncating variants (TTNtv) may be responsible for a wide spectrum of musculoskeletal and cardiac disorders with different age at onset. Although the prevalence of heterozygous TTNtv is relatively high in the general population, cardiac phenotyping (mainly cardiomyopathies, CMPs) in biallelic titinopathy has rarely been described in children. Methods We reviewed the medical records of pediatric patients with biallelic TTNtv and cardiac involvement. Clinical exome sequencing excluded pathogenic/likely pathogenic variants in major CMP genes. Results Five pediatric patients (four male) with biallelic TTNtv were included. Major arthrogryposis multiplex was observed in four patients; no patient showed intellectual disability. At a cardiac level, congenital heart defects (atrial and ventricular septal defects, n = 3) and left ventricular non-compaction (n = 1) were reported. All patients had dilated cardiomyopathy (DCM) diagnosed at birth in one patient and at the age of 10, 13, 14, and 17 years in the other four patients. Heart rhythm monitoring showed tachyarrhythmias (premature ventricular contractions, n = 2; non-sustained ventricular tachycardia, n = 2) and nocturnal first-degree atrio-ventricular block (n = 2). Cardiac magnetic resonance (CMR) imaging was performed in all patients and revealed a peculiar late gadolinium enhancement distribution in three patients. HyperCKemia was present in two patients and end-stage heart failure in four. End-organ damage requiring heart transplantation (HT) was indicated in two patients, who were operated on successfully. Conclusion Biallelic TTNtv should be considered when evaluating children with severe and early-onset DCM, particularly if skeletal and muscular abnormalities are present, e.g., arthrogryposis multiplex and congenital progressive myopathy. End-stage heart failure is common and may require HT.
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Affiliation(s)
- Anwar Baban
- Pediatric Cardiology and Arrhythmia/Syncope Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Marianna Cicenia
- Pediatric Cardiology and Arrhythmia/Syncope Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Monia Magliozzi
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Giovanni Parlapiano
- Pediatric Cardiology and Arrhythmia/Syncope Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Marco Cirillo
- Department of Imaging, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Giulia Pascolini
- Pediatric Cardiology and Arrhythmia/Syncope Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Fabiana Fattori
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Maria Gnazzo
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Pasqualina Bruno
- Department of Cardiac Surgery, Cardiology, Heart and Lung Transplantation, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Lorenzo De Luca
- Pediatric Cardiology and Arrhythmia/Syncope Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Luca Di Chiara
- Pediatric Cardiac Intensive Care Unit, Department of Cardiology and Cardiac Surgery, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Paola Francalanci
- Department of Pathology, Bambino Gesù Children’s Hospital and Research Institute, IRCCS, Rome, Italy
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
| | - Aurelio Secinaro
- Advanced Cardiothoracic Imaging Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Antonio Amodeo
- Heart Failureand Transplant, Mechanical Circulatory Support Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Fabrizio Drago
- Pediatric Cardiology and Arrhythmia/Syncope Complex Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
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21
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Barefield DY, Alvarez-Arce A, Araujo KN. Mechanisms of Sarcomere Protein Mutation-Induced Cardiomyopathies. Curr Cardiol Rep 2023; 25:473-484. [PMID: 37060436 PMCID: PMC11141690 DOI: 10.1007/s11886-023-01876-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 04/16/2023]
Abstract
PURPOSE OF REVIEW The pace of identifying cardiomyopathy-associated mutations and advances in our understanding of sarcomere function that underlies many cardiomyopathies has been remarkable. Here, we aim to synthesize how these advances have led to the promising new treatments that are being developed to treat cardiomyopathies. RECENT FINDINGS The genomics era has identified and validated many genetic causes of hypertrophic and dilated cardiomyopathies. Recent advances in our mechanistic understanding of sarcomere pathophysiology include high-resolution molecular models of sarcomere components and the identification of the myosin super-relaxed state. The advances in our understanding of sarcomere function have yielded several therapeutic agents that are now in development and clinical use to correct contractile dysfunction-mediated cardiomyopathy. New genes linked to cardiomyopathy include targets with limited clinical evidence and require additional investigation. Large portions of cardiomyopathy with family history remain genetically undiagnosed and may be due to polygenic disease.
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Affiliation(s)
- David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA.
| | - Alejandro Alvarez-Arce
- Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA
| | - Kelly N Araujo
- Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA
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22
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A Novel Nonsense Pathogenic TTN Variant Identified in a Patient with Severe Dilated Cardiomyopathy. Curr Issues Mol Biol 2023; 45:2422-2430. [PMID: 36975527 PMCID: PMC10047881 DOI: 10.3390/cimb45030157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
Both genetic and environmental factors contribute to the development of dilated cardiomyopathy. Among the genes involved, TTN mutations, including truncated variants, explain 25% of DCM cases. We performed genetic counseling and analysis on a 57-year-old woman diagnosed with severe DCM and presenting relevant acquired risk factors for DCM (hypertension, diabetes, smoking habit, and/or previous alcohol and cocaine abuse) and with a family history of both DCM and sudden cardiac death. The left ventricular systolic function, as assessed by standard echocardiography, was 20%. The genetic analysis performed using TruSight Cardio panel, including 174 genes related to cardiac genetic diseases, revealed a novel nonsense TTN variant (TTN:c.103591A > T, p.Lys34531*), falling within the M-band region of the titin protein. This region is known for its important role in maintaining the structure of the sarcomere and in promoting sarcomerogenesis. The identified variant was classified as likely pathogenic based on ACMG criteria. The current results support the need of genetic analysis in the presence of a family history, even when relevant acquired risk factors for DCM may have contributed to the severity of the disease.
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23
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Parker F, Tang AAS, Rogers B, Carrington G, dos Remedios C, Li A, Tomlinson D, Peckham M. Affimers targeting proteins in the cardiomyocyte Z-disc: Novel tools that improve imaging of heart tissue. Front Cardiovasc Med 2023; 10:1094563. [PMID: 36865889 PMCID: PMC9971620 DOI: 10.3389/fcvm.2023.1094563] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Dilated Cardiomyopathy is a common form of heart failure. Determining how this disease affects the structure and organization of cardiomyocytes in the human heart is important in understanding how the heart becomes less effective at contraction. Here we isolated and characterised Affimers (small non-antibody binding proteins) to Z-disc proteins ACTN2 (α-actinin-2), ZASP (also known as LIM domain binding protein 3 or LDB3) and the N-terminal region of the giant protein titin (TTN Z1-Z2). These proteins are known to localise in both the sarcomere Z-discs and the transitional junctions, found close to the intercalated discs that connect adjacent cardiomyocytes. We use cryosections of left ventricles from two patients diagnosed with end-stage Dilated Cardiomyopathy who underwent Orthotopic Heart Transplantation and were whole genome sequenced. We describe how Affimers substantially improve the resolution achieved by confocal and STED microscopy compared to conventional antibodies. We quantified the expression of ACTN2, ZASP and TTN proteins in two patients with dilated cardiomyopathy and compared them with a sex- and age-matched healthy donor. The small size of the Affimer reagents, combined with a small linkage error (the distance from the epitope to the dye label covalently bound to the Affimer) revealed new structural details in Z-discs and intercalated discs in the failing samples. Affimers are thus useful for analysis of changes to cardiomyocyte structure and organisation in diseased hearts.
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Affiliation(s)
- Francine Parker
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Anna A. S. Tang
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Brendan Rogers
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Glenn Carrington
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Cris dos Remedios
- Mechanobiology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Amy Li
- Sydney Heart Bank, The University of Sydney, Sydney, NSW, Australia
- Department of Pharmacy & Biomedical Sciences, La Trobe University, Bendigo, VIC, Australia
- Centre for Healthy Futures, Torrens University Australia, Surrey Hills, NSW, Australia
| | - Darren Tomlinson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Michelle Peckham
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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24
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Verdonschot JA, Wang P, Derks KW, Adriaens ME, Stroeks SL, Henkens MT, Raafs AG, Sikking M, de Koning B, van den Wijngaard A, Krapels IP, Nabben M, Brunner HG, Heymans SR. Clustering of Cardiac Transcriptome Profiles Reveals Unique. JACC Basic Transl Sci 2023; 8:406-418. [PMID: 37138803 PMCID: PMC10149655 DOI: 10.1016/j.jacbts.2022.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/26/2022] [Accepted: 10/26/2022] [Indexed: 02/04/2023]
Abstract
Dilated cardiomyopathy is a heterogeneous disease characterized by multiple genetic and environmental etiologies. The majority of patients are treated the same despite these differences. The cardiac transcriptome provides information on the patient's pathophysiology, which allows targeted therapy. Using clustering techniques on data from the genotype, phenotype, and cardiac transcriptome of patients with early- and end-stage dilated cardiomyopathy, more homogeneous patient subgroups are identified based on shared underlying pathophysiology. Distinct patient subgroups are identified based on differences in protein quality control, cardiac metabolism, cardiomyocyte function, and inflammatory pathways. The identified pathways have the potential to guide future treatment and individualize patient care.
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25
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Gu JN, Yang CX, Ding YY, Qiao Q, Di RM, Sun YM, Wang J, Yang L, Xu YJ, Yang YQ. Identification of BMP10 as a Novel Gene Contributing to Dilated Cardiomyopathy. Diagnostics (Basel) 2023; 13:diagnostics13020242. [PMID: 36673052 PMCID: PMC9857772 DOI: 10.3390/diagnostics13020242] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 12/20/2022] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
Dilated cardiomyopathy (DCM), characterized by left ventricular or biventricular enlargement with systolic dysfunction, is the most common type of cardiac muscle disease. It is a major cause of congestive heart failure and the most frequent indication for heart transplantation. Aggregating evidence has convincingly demonstrated that DCM has an underlying genetic basis, though the genetic defects responsible for DCM in a larger proportion of cases remain elusive, motivating the ongoing research for new DCM-causative genes. In the current investigation, a multigenerational family affected with autosomal-dominant DCM was recruited from the Chinese Han population. By whole-exome sequencing and Sanger sequencing analyses of the DNAs from the family members, a new BMP10 variation, NM_014482.3:c.166C > T;p.(Gln56*), was discovered and verified to be in co-segregation with the DCM phenotype in the entire family. The heterozygous BMP10 variant was not detected in 268 healthy volunteers enrolled as control subjects. The functional measurement via dual-luciferase reporter assay revealed that Gln56*-mutant BMP10 lost the ability to transactivate its target genes NKX2.5 and TBX20, two genes that had been causally linked to DCM. The findings strongly indicate BMP10 as a new gene contributing to DCM in humans and support BMP10 haploinsufficiency as an alternative pathogenic mechanism underpinning DCM, implying potential implications for the early genetic diagnosis and precision prophylaxis of DCM.
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Affiliation(s)
- Jia-Ning Gu
- Department of Cardiology, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
| | - Chen-Xi Yang
- Department of Cardiology, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
| | - Yuan-Yuan Ding
- Shanghai Health Development Research Center, Shanghai Medical Information Center, Shanghai 200031, China
| | - Qi Qiao
- Department of Cardiology, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
| | - Ruo-Min Di
- Department of Cardiology, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
| | - Yu-Min Sun
- Department of Cardiology, Shanghai Jing’an District Central Hospital, Fudan University, Shanghai 200040, China
| | - Jun Wang
- Department of Cardiology, Shanghai Jing’an District Central Hospital, Fudan University, Shanghai 200040, China
| | - Ling Yang
- Department of Ultrasound, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
- Correspondence: (Y.-J.X.); (Y.-Q.Y.)
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
- Department of Cardiovascular Research Laboratory, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
- Department of Central Laboratory, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
- Correspondence: (Y.-J.X.); (Y.-Q.Y.)
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26
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Kim YG, Ha C, Shin S, Park JH, Jang JH, Kim JW. Enrichment of titin-truncating variants in exon 327 in dilated cardiomyopathy and its relevance to reduced nonsense-mediated mRNA decay efficiency. Front Genet 2023; 13:1087359. [PMID: 36685919 PMCID: PMC9845391 DOI: 10.3389/fgene.2022.1087359] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/07/2022] [Indexed: 01/05/2023] Open
Abstract
Titin truncating variants (TTNtvs) are the most common genetic cause of dilated cardiomyopathy (DCM). Among four regions of titin, A-band enrichment of DCM-causing TTNtvs is widely accepted but the underlying mechanism is still unknown. Meanwhile, few reports have identified exon 327 as a highly mutated A-band exon but the degree of exon 327 enrichment has not been quantitatively investigated. To find the real hotspot of DCM-causing TTNtvs, we aimed to reassess the degree of TTNtv enrichment in known titin regions and in exon 327, separately. In addition, we tried to explain exon 327 clustering in terms of nonsense-mediated mRNA decay (NMD) efficiency and a dominant negative mechanism recently proposed. Research papers focusing on TTNtvs found in patients with DCM were collected. A total of 612 patients with TTNtv-realated DCM were obtained from 10 studies. In the four regions of TTN and exon 327, the degree of TTNtvs enrichment was calculated in a way that the effect of distribution of highly expressed exons was normalized. As a result, exon 327 was the only region that showed significant enrichment for DCM-related TTNtv (p < .001). On the other hand, other A-band exons had almost the same number of TTNtv of random distribution. A review of RNAseq data revealed that the median allelic imbalance deviation of exon 327 TTNtvs was .04, indicating almost zero NMD. From these findings, we propose that the widely accepted A-band enrichment of DCM-related TTNtv is mostly attributable to exon 327 enrichment. In addition, based on the recently demonstrated dominant negative mechanism, the extremely low NMD efficiency seems to contribute to exon 327 enrichment.
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Affiliation(s)
- Young-gon Kim
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Changhee Ha
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Sunghwan Shin
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jong-ho Park
- Clinical Genomics Center, Samsung Medical Center, Seoul, South Korea
| | - Ja-Hyun Jang
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jong-Won Kim
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea,Clinical Genomics Center, Samsung Medical Center, Seoul, South Korea,*Correspondence: Jong-Won Kim,
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27
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Titin-truncating variants in hiPSC cardiomyocytes induce pathogenic proteinopathy and sarcomere defects with preserved core contractile machinery. Stem Cell Reports 2022; 18:220-236. [PMID: 36525964 PMCID: PMC9860080 DOI: 10.1016/j.stemcr.2022.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 12/23/2022] Open
Abstract
Titin-truncating variants (TTNtv) are the single largest genetic cause of dilated cardiomyopathy (DCM). In this study we modeled disease phenotypes of A-band TTNtv-induced DCM in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) using genome editing and tissue engineering technologies. Transcriptomic, cellular, and micro-tissue studies revealed that A-band TTNtv hiPSC-CMs exhibit pathogenic proteinopathy, sarcomere defects, aberrant Na+ channel activities, and contractile dysfunction. These phenotypes establish a dual mechanism of poison peptide effect and haploinsufficiency that collectively contribute to DCM pathogenesis. However, TTNtv cellular defects did not interfere with the function of the core contractile machinery, the actin-myosin-troponin-Ca2+ complex, and preserved the therapeutic mechanism of sarcomere modulators. Treatment of TTNtv cardiac micro-tissues with investigational sarcomere modulators augmented contractility and resulted in sustained transcriptomic changes that promote reversal of DCM disease signatures. Together, our findings elucidate the underlying pathogenic mechanisms of A-band TTNtv-induced DCM and demonstrate the validity of sarcomere modulators as potential therapeutics.
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28
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Guo Y, Wang J, Guo X, Gao R, Yang C, Li L, Sun Y, Qiu X, Xu Y, Yang Y. KLF13 Loss‐of‐Function Mutations Underlying Familial Dilated Cardiomyopathy. J Am Heart Assoc 2022; 11:e027578. [DOI: 10.1161/jaha.122.027578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Background
Dilated cardiomyopathy (DCM), characterized by progressive left ventricular enlargement and systolic dysfunction, is the most common type of cardiomyopathy and a leading cause of heart failure and cardiac death. Accumulating evidence underscores the critical role of genetic defects in the pathogenesis of DCM, and >250 genes have been implicated in DCM to date. However, DCM is of substantial genetic heterogeneity, and the genetic basis underpinning DCM remains elusive in most cases.
Methods and Results
By genome‐wide scan with microsatellite markers and genetic linkage analysis in a 4‐generation family inflicted with autosomal‐dominant DCM, a new locus for DCM was mapped on chromosome 15q13.1–q13.3, a 4.77‐cM (≈3.43 Mbp) interval between markers D15S1019 and D15S1010, with the largest 2‐point logarithm of odds score of 5.1175 for the marker D15S165 at recombination fraction (θ)=0.00. Whole‐exome sequencing analyses revealed that within the mapping chromosomal region, only the mutation in the
KLF13
gene, c.430G>T (p.E144X), cosegregated with DCM in the family. In addition, sequencing analyses of
KLF13
in another cohort of 266 unrelated patients with DCM and their available family members unveiled 2 new mutations, c.580G>T (p.E194X) and c.595T>C (p.C199R), which cosegregated with DCM in 2 families, respectively. The 3 mutations were absent from 418 healthy subjects. Functional assays demonstrated that the 3 mutants had no transactivation on the target genes
ACTC1
and
MYH7
(2 genes causally linked to DCM), alone or together with GATA4 (another gene contributing to DCM), and a diminished ability to bind the promoters of
ACTC1
and
MYH7
. Add, the E144X‐mutant KLF13 showed a defect in intracellular distribution.
Conclusions
This investigation indicates
KLF13
as a new gene predisposing to DCM, which adds novel insight to the molecular pathogenesis underlying DCM, implying potential implications for prenatal prevention and precision treatment of DCM in a subset of patients.
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Affiliation(s)
- Yu‐Han Guo
- Department of Cardiology, Shanghai Fifth People’s Hospital Fudan University Shanghai China
| | - Jun Wang
- Department of Cardiology, Shanghai Jing’an District Central Hospital Fudan University Shanghai China
| | - Xiao‐Juan Guo
- Department of Cardiology, Shanghai Fifth People’s Hospital Fudan University Shanghai China
| | - Ri‐Feng Gao
- Department of Cardiology, Shanghai Fifth People’s Hospital Fudan University Shanghai China
| | - Chen‐Xi Yang
- Department of Cardiology, Shanghai Fifth People’s Hospital Fudan University Shanghai China
| | - Li Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital Tongji University School of Medicine Shanghai China
- Institute of Medical Genetics Tongji University Shanghai China
| | - Yu‐Min Sun
- Department of Cardiology, Shanghai Jing’an District Central Hospital Fudan University Shanghai China
| | - Xing‐Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital Shanghai Jiao Tong University Shanghai China
| | - Ying‐Jia Xu
- Department of Cardiology, Shanghai Fifth People’s Hospital Fudan University Shanghai China
| | - Yi‐Qing Yang
- Department of Cardiology, Shanghai Fifth People’s Hospital Fudan University Shanghai China
- Cardiovascular Research Laboratory and Central Laboratory, Shanghai Fifth People’s Hospital Fudan University Shanghai China
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29
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Marcello M, Cetrangolo V, Savarese M, Udd B. Use of animal models to understand titin physiology and pathology. J Cell Mol Med 2022; 26:5103-5112. [PMID: 36065969 PMCID: PMC9575118 DOI: 10.1111/jcmm.17533] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/01/2022] Open
Abstract
In recent years, increasing attention has been paid to titin (TTN) and its mutations. Heterozygous TTN truncating variants (TTNtv) increase the risk of a cardiomyopathy. At the same time, TTNtv and few missense variants have been identified in patients with mainly recessive skeletal muscle diseases. The pathogenic mechanisms underlying titin‐related diseases are still partly unknown. Similarly, the titin mechanical and functional role in the muscle contraction are far from being exhaustively clarified. In the last few years, several animal models carrying variants in the titin gene have been developed and characterized to study the structural and mechanical properties of specific titin domains or to mimic patients' mutations. This review describes the main animal models so far characterized, including eight mice models and three fish models (Medaka and Zebrafish) and discusses the useful insights provided by a thorough characterization of the cell‐, tissue‐ and organism‐phenotypes in these models.
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Affiliation(s)
| | | | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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30
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Molecular genetic mechanisms of dilated cardiomyopathy. Curr Opin Genet Dev 2022; 76:101959. [PMID: 35870234 DOI: 10.1016/j.gde.2022.101959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 11/20/2022]
Abstract
Heart failure (HF) is a rapidly growing cardiovascular condition with a prevalence of ~40 million individuals worldwide [1]. While HF can be caused by acquired conditions such as myocardial infarctions and viruses [2], the genetic basis for HF is rapidly emerging particularly for dilated cardiomyopathy (DCM) that is the most prevalent HF type. In this review, insights from the rapid expansion in next-generation sequencing technologies applied in the HF clinic are merged with recent functional genomics studies to provide a contemporary view of DCM molecular genetics.
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31
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Abstract
PURPOSE OF REVIEW Truncating TTN variants (TTNtv) are the most common genetic cause of dilated cardiomyopathy (DCM), but the underlying mechanisms are incompletely understood and effective therapeutic strategies are lacking. Here we review recent data that shed new light on the functional consequences of TTNtv and how these effects may vary with mutation location. RECENT FINDINGS Whether TTNtv act by haploinsufficiency or dominant negative effects has been hotly debated. New evidence now implicates both mechanisms in TTNtv-related DCM, showing reduced titin content and persistent truncated titin that may be incorporated into protein aggregates. The extent to which aggregate formation and protein quality control defects differ with TTNtv location and contribute to contractile dysfunction is unresolved. TTNtv-associated DCM has a complex etiology that involves varying combinations of wild-type titin deficiency and dominant negative effects of truncated mutant titin. Therapeutic strategies to improve protein handling may be beneficial in some cases.
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Exploring the Potential of Symmetric Exon Deletion to Treat Non-Ischemic Dilated Cardiomyopathy by Removing Frameshift Mutations in TTN. Genes (Basel) 2022; 13:genes13061093. [PMID: 35741855 PMCID: PMC9222585 DOI: 10.3390/genes13061093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/30/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022] Open
Abstract
Non-ischemic dilated cardiomyopathy (DCM) is one of the most frequent pathologies requiring cardiac transplants. Even though the etiology of this disease is complex, frameshift mutations in the giant sarcomeric protein Titin could explain up to 25% of the familial and 18% of the sporadic cases of DCM. Many studies have shown the potential of genome editing using CRISPR/Cas9 to correct truncating mutations in sarcomeric proteins and have established the grounds for myoediting. However, these therapies are still in an immature state, with only few studies showing an efficient treatment of cardiac diseases. This publication hypothesizes that the Titin (TTN)-specific gene structure allows the application of myoediting approaches in a broad range of locations to reframe TTNtvvariants and to treat DCM patients. Additionally, to pave the way for the generation of efficient myoediting approaches for DCM, we screened and selected promising target locations in TTN. We conceptually explored the deletion of symmetric exons as a therapeutic approach to restore TTN’s reading frame in cases of frameshift mutations. We identified a set of 94 potential candidate exons of TTN that we consider particularly suitable for this therapeutic deletion. With this study, we aim to contribute to the development of new therapies to efficiently treat titinopathies and other diseases caused by mutations in genes encoding proteins with modular structures, e.g., Obscurin.
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33
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Abstract
Cardiovascular complications of pregnancy have risen substantially over the past decades, and now account for the majority of pregnancy-induced maternal deaths, as well as having substantial long-term consequences on maternal cardiovascular health. The causes and pathophysiology of these complications remain poorly understood, and therapeutic options are limited. Preclinical models represent a crucial tool for understanding human disease. We review here advances made in preclinical models of cardiovascular complications of pregnancy, including preeclampsia and peripartum cardiomyopathy, with a focus on pathological mechanisms elicited by the models and on relevance to human disease.
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Affiliation(s)
- Zolt Arany
- Department of Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia (Z.A.)
| | - Denise Hilfiker-Kleiner
- Institute of Cardiovascular Complications in Pregnancy and in Oncologic Therapies, Philipps University Marburg, Germany (D.H.-K.)
| | - S Ananth Karumanchi
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (S.A.K.)
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34
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Genetic Insights into Primary Restrictive Cardiomyopathy. J Clin Med 2022; 11:jcm11082094. [PMID: 35456187 PMCID: PMC9027761 DOI: 10.3390/jcm11082094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Restrictive cardiomyopathy is a rare cardiac disease causing severe diastolic dysfunction, ventricular stiffness and dilated atria. In consequence, it induces heart failure often with preserved ejection fraction and is associated with a high mortality. Since it is a poor clinical prognosis, patients with restrictive cardiomyopathy frequently require heart transplantation. Genetic as well as non-genetic factors contribute to restrictive cardiomyopathy and a significant portion of cases are of unknown etiology. However, the genetic forms of restrictive cardiomyopathy and the involved molecular pathomechanisms are only partially understood. In this review, we summarize the current knowledge about primary genetic restrictive cardiomyopathy and describe its genetic landscape, which might be of interest for geneticists as well as for cardiologists.
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35
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Abstract
Variants in >12 genes encoding sarcomeric proteins can cause various cardiomyopathies. The two most common are hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Current therapeutics do not target the root causes of these diseases, but attempt to prevent disease progression and/or to manage symptoms. Accordingly, novel approaches are being developed to treat the cardiac muscle dysfunction directly. Challenges to developing therapeutics for these diseases include the diverse mechanisms of pathogenesis, some of which are still being debated and defined. Four small molecules that modulate the myosin motor protein in the cardiac sarcomere have shown great promise in the settings of HCM and DCM, regardless of the underlying genetic pathogenesis, and similar approaches are being developed to target other components of the sarcomere. In the setting of HCM, mavacamten and aficamten bind to the myosin motor and decrease the ATPase activity of myosin. In the setting of DCM, omecamtiv mecarbil and danicamtiv increase myosin activity in cardiac muscle (but omecamtiv mecarbil decreases myosin activity in vitro). In this Review, we discuss the therapeutic strategies to alter sarcomere contractile activity and summarize the data indicating that targeting one protein in the sarcomere can be effective in treating patients with genetic variants in other sarcomeric proteins, as well as in patients with non-sarcomere-based disease.
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36
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37
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Fomin A, Gärtner A, Cyganek L, Tiburcy M, Tuleta I, Wellers L, Folsche L, Hobbach AJ, von Frieling-Salewsky M, Unger A, Hucke A, Koser F, Kassner A, Sielemann K, Streckfuß-Bömeke K, Hasenfuss G, Goedel A, Laugwitz KL, Moretti A, Gummert JF, Dos Remedios CG, Reinecke H, Knöll R, van Heesch S, Hubner N, Zimmermann WH, Milting H, Linke WA. Truncated titin proteins and titin haploinsufficiency are targets for functional recovery in human cardiomyopathy due to TTN mutations. Sci Transl Med 2021; 13:eabd3079. [PMID: 34731013 DOI: 10.1126/scitranslmed.abd3079] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Andrey Fomin
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany
| | - Anna Gärtner
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Lukas Cyganek
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Stem Cell Unit, University Medical Center, 37075 Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany
| | - Malte Tiburcy
- German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany
| | - Izabela Tuleta
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, 48149 University Hospital Münster, Münster, Germany
| | - Luisa Wellers
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Lina Folsche
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Anastasia J Hobbach
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, 48149 University Hospital Münster, Münster, Germany
| | | | - Andreas Unger
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Anna Hucke
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Franziska Koser
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Astrid Kassner
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Katharina Sielemann
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Katrin Streckfuß-Bömeke
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany
| | - Alexander Goedel
- First Medical Department, Cardiology, Technical University of Munich, 81675 Munich, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Munich, Germany.,Department of Cell and Molecular Biology, Karolinska Institute, S-17177 Stockholm, Sweden
| | - Karl-Ludwig Laugwitz
- First Medical Department, Cardiology, Technical University of Munich, 81675 Munich, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Munich, Germany.,Munich Heart Alliance, 80802 Munich, Germany
| | - Alessandra Moretti
- First Medical Department, Cardiology, Technical University of Munich, 81675 Munich, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Munich, Germany.,Munich Heart Alliance, 80802 Munich, Germany
| | - Jan F Gummert
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany.,Department of Cardio-Thoracic Surgery, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | | | - Holger Reinecke
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, 48149 University Hospital Münster, Münster, Germany
| | - Ralph Knöll
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institute, S-17177 Stockholm, Sweden.,Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Sebastiaan van Heesch
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Berlin, Germany.,Princess Máxima Center for Pediatric Oncology, 3584 CT Utrecht, Netherlands
| | - Norbert Hubner
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Berlin, Germany.,Charité-Universitätsmedizin, 10117 Berlin, Germany.,Berlin Institute of Health, 10178 Berlin, Germany
| | - Wolfram H Zimmermann
- German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells," University of Göttingen, 37073 Göttingen, Germany
| | - Hendrik Milting
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Wolfgang A Linke
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Institute of Physiology II, University of Münster, 48149 Münster, Germany
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38
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Loescher CM, Hobbach AJ, Linke WA. Titin (TTN): from molecule to modifications, mechanics and medical significance. Cardiovasc Res 2021; 118:2903-2918. [PMID: 34662387 PMCID: PMC9648829 DOI: 10.1093/cvr/cvab328] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/13/2021] [Indexed: 12/19/2022] Open
Abstract
The giant sarcomere protein titin is a major determinant of cardiomyocyte stiffness and contributor to cardiac strain sensing. Titin-based forces are highly regulated in health and disease, which aids in the regulation of myocardial function, including cardiac filling and output. Due to the enormous size, complexity, and malleability of the titin molecule, titin properties are also vulnerable to dysregulation, as observed in various cardiac disorders. This review provides an overview of how cardiac titin properties can be changed at a molecular level, including the role isoform diversity and post-translational modifications (acetylation, oxidation, and phosphorylation) play in regulating myocardial stiffness and contractility. We then consider how this regulation becomes unbalanced in heart disease, with an emphasis on changes in titin stiffness and protein quality control. In this context, new insights into the key pathomechanisms of human cardiomyopathy due to a truncation in the titin gene (TTN) are discussed. Along the way, we touch on the potential for titin to be therapeutically targeted to treat acquired or inherited cardiac conditions, such as HFpEF or TTN-truncation cardiomyopathy.
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Affiliation(s)
- Christine M Loescher
- Institute of Physiology II, University Hospital Münster, Robert-Koch-Str. 27B, Münster, 48149 Germany
| | - Anastasia J Hobbach
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, University Hospital Münster, Münster, Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, Robert-Koch-Str. 27B, Münster, 48149 Germany
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