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Ragusa R, Caselli C. Focus on cardiac troponin complex: From gene expression to cardiomyopathy. Genes Dis 2024; 11:101263. [PMID: 39211905 PMCID: PMC11357864 DOI: 10.1016/j.gendis.2024.101263] [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: 10/03/2023] [Revised: 01/26/2024] [Accepted: 02/21/2024] [Indexed: 09/04/2024] Open
Abstract
The cardiac troponin complex (cTn) is a regulatory component of sarcomere. cTn consists of three subunits: cardiac troponin C (cTnC), which confers Ca2+ sensitivity to muscle; cTnI, which inhibits the interaction of cross-bridge of myosin with thin filament during diastole; and cTnT, which has multiple roles in sarcomere, such as promoting the link between the cTnI-cTnC complex and tropomyosin within the thin filament and influencing Ca2+ sensitivity of cTn and force development during contraction. Conditions that interfere with interactions within cTn and/or other thin filament proteins can be key factors in the regulation of cardiac contraction. These conditions include alterations in myofilament Ca2+ sensitivity, direct changes in cTn function, and triggering downstream events that lead to adverse cardiac remodeling and impairment of heart function. This review describes gene expression and post-translational modifications of cTn as well as the conditions that can adversely affect the delicate balance among the components of cTn, thereby promoting contractile dysfunction.
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Affiliation(s)
- Rosetta Ragusa
- Institute of Clinical Physiology, CNR, via Moruzzi 1, Pisa 56124, Italy
| | - Chiara Caselli
- Institute of Clinical Physiology, CNR, via Moruzzi 1, Pisa 56124, Italy
- Fondazione Toscana Gabriele Monasterio, via Moruzzi 1, Pisa 56124, Italy
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Hey TM, Rasmussen TB, Madsen T, Aagaard MM, Harbo M, Mølgaard H, Nielsen SK, Haas J, Meder B, Møller JE, Eiskjær H, Mogensen J. Clinical and Genetic Investigations of 109 Index Patients With Dilated Cardiomyopathy and 445 of Their Relatives. Circ Heart Fail 2020; 13:e006701. [PMID: 33019804 DOI: 10.1161/circheartfailure.119.006701] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND It was the aim to investigate the frequency and genetic basis of dilated cardiomyopathy (DCM) among relatives of index patients with unexplained heart failure at a tertiary referral center. METHODS Clinical investigations were performed in 109 DCM index patients and 445 of their relatives. All index patients underwent genetic investigations of 76 disease-associated DCM genes. A family history of DCM occurred in 11% (n=12) while clinical investigations identified familial DCM in a total of 32% (n=35). One-fifth of all relatives (n=95) had DCM of whom 60% (n=57) had symptoms of heart failure at diagnosis, whereas 40% (n=38) were asymptomatic. Symptomatic relatives had a shorter event-free survival than asymptomatic DCM relatives (P<0.001). RESULTS Genetic investigations identified 43 pathogenic (n=27) or likely pathogenic (n=16) variants according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology criteria. Forty-four percent (n=48/109) of index patients carried a pathogenic/likely pathogenic variant of whom 36% (n=27/74) had sporadic DCM, whereas 60% (21/35) were familial cases. Thirteen of the pathogenic/likely pathogenic variants were also present in ≥7 affected individuals and thereby considered to be of sufficient high confidence for use in predictive genetic testing. CONCLUSIONS A family history of DCM identified only 34% (n=12/35) of hereditary DCM, whereas systematic clinical screening identified the remaining 66% (n=23) of DCM families. This emphasized the importance of clinical investigations to identify familial DCM. The high number of pathogenic/likely pathogenic variants identified in familial DCM provides a firm basis for offering genetic investigations in affected families. This should also be considered in sporadic cases since adequate family evaluation may not always be possible and the results of the genetic investigations may carry prognostic information with an impact on individual management.
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Affiliation(s)
- Thomas M Hey
- Department of Cardiology, Odense University Hospital, Denmark (T.M.H., S.K.N., J.E.M., J.M.)
- Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Denmark (T.M.H., .K.N., J.E.M., J.M.)
| | - Torsten B Rasmussen
- Department of Cardiology, Aarhus University Hospital, Denmark (T.B.R., H.M., H.E.)
| | - Trine Madsen
- Department of Cardiology Aalborg University Hospital, Denmark (T.M.)
| | | | - Maria Harbo
- Department of Clinical Genetics, Vejle Hospital, Denmark (M.H., M.M.A.)
| | - Henning Mølgaard
- Department of Cardiology, Aarhus University Hospital, Denmark (T.B.R., H.M., H.E.)
| | - Søren K Nielsen
- Department of Cardiology, Odense University Hospital, Denmark (T.M.H., S.K.N., J.E.M., J.M.)
- Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Denmark (T.M.H., .K.N., J.E.M., J.M.)
| | - Jan Haas
- Institue for Cardiomyopathies Heidelberg, Department of Internal Medicine III (J.H., B.M.), University of Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), Germany (J.H., B.M.)
| | - Benjamin Meder
- Institue for Cardiomyopathies Heidelberg, Department of Internal Medicine III (J.H., B.M.), University of Heidelberg, Germany
- Klaus Tschira Institute für Computational Cardiology (B.M.), University of Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), Germany (J.H., B.M.)
| | - Jacob E Møller
- Department of Cardiology, Odense University Hospital, Denmark (T.M.H., S.K.N., J.E.M., J.M.)
- Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Denmark (T.M.H., .K.N., J.E.M., J.M.)
| | - Hans Eiskjær
- Department of Cardiology, Aarhus University Hospital, Denmark (T.B.R., H.M., H.E.)
| | - Jens Mogensen
- Department of Cardiology, Odense University Hospital, Denmark (T.M.H., S.K.N., J.E.M., J.M.)
- Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Denmark (T.M.H., .K.N., J.E.M., J.M.)
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England J, Loughna S, Rutland CS. Multiple Species Comparison of Cardiac Troponin T and Dystrophin: Unravelling the DNA behind Dilated Cardiomyopathy. J Cardiovasc Dev Dis 2017; 4:E8. [PMID: 29367539 PMCID: PMC5715711 DOI: 10.3390/jcdd4030008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/01/2017] [Accepted: 07/05/2017] [Indexed: 12/14/2022] Open
Abstract
Animals have frequently been used as models for human disorders and mutations. Following advances in genetic testing and treatment options, and the decreasing cost of these technologies in the clinic, mutations in both companion and commercial animals are now being investigated. A recent review highlighted the genes associated with both human and non-human dilated cardiomyopathy. Cardiac troponin T and dystrophin were observed to be associated with both human and turkey (troponin T) and canine (dystrophin) dilated cardiomyopathies. This review gives an overview of the work carried out in cardiac troponin T and dystrophin to date in both human and animal dilated cardiomyopathy.
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Affiliation(s)
- Jennifer England
- School of Life Sciences, Medical School, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
| | - Siobhan Loughna
- School of Life Sciences, Medical School, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
| | - Catrin Sian Rutland
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, UK.
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Dewan S, McCabe KJ, Regnier M, McCulloch AD. Insights and Challenges of Multi-Scale Modeling of Sarcomere Mechanics in cTn and Tm DCM Mutants-Genotype to Cellular Phenotype. Front Physiol 2017; 8:151. [PMID: 28352236 PMCID: PMC5348544 DOI: 10.3389/fphys.2017.00151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/24/2017] [Indexed: 01/18/2023] Open
Abstract
Dilated Cardiomyopathy (DCM) is a leading cause of sudden cardiac death characterized by impaired pump function and dilatation of cardiac ventricles. In this review we discuss various in silico approaches to elucidating the mechanisms of genetic mutations leading to DCM. The approaches covered in this review focus on bridging the spatial and temporal gaps that exist between molecular and cellular processes. Mutations in sarcomeric regulatory thin filament proteins such as the troponin complex (cTn) and Tropomyosin (Tm) have been associated with DCM. Despite the experimentally-observed myofilament measures of contractility in the case of these mutations, the mechanisms by which the underlying molecular changes and protein interactions scale up to organ failure by these mutations remains elusive. The review highlights multi-scale modeling approaches and their applicability to study the effects of sarcomeric gene mutations in-silico. We discuss some of the insights that can be gained from computational models of cardiac biomechanics when scaling from molecular states to cellular level.
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Affiliation(s)
- Sukriti Dewan
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kimberly J McCabe
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Michael Regnier
- Departments of Bioengineering and Medicine, University of Washington Seattle, WA, USA
| | - Andrew D McCulloch
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
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Long PA, Larsen BT, Evans JM, Olson TM. Exome Sequencing Identifies Pathogenic and Modifier Mutations in a Child With Sporadic Dilated Cardiomyopathy. J Am Heart Assoc 2015; 4:JAHA.115.002443. [PMID: 26656454 PMCID: PMC4845292 DOI: 10.1161/jaha.115.002443] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background Idiopathic dilated cardiomyopathy (DCM) is typically diagnosed in adulthood, yet familial cases exhibit variable age‐dependent penetrance and a subset of patients develop sporadic DCM in childhood. We sought to discover the molecular basis of sporadic DCM in an 11‐year‐old female with severe heart failure necessitating cardiac transplantation. Methods and Results Parental echocardiograms excluded asymptomatic DCM. Whole exome sequencing was performed on the family trio and filtered for rare, deleterious, recessive, and de novo variants. Of the 8 candidate genes identified, only 2 had a role in cardiac physiology. A de novo missense mutation in TNNT2 was identified, previously reported and functionally validated in familial DCM with markedly variable penetrance. Additionally, recessive compound heterozygous truncating mutations were identified in XIRP2, a member of the ancient Xin gene family, which governs intercalated disc (ICD) maturation. Histomorphological analysis of explanted heart tissue revealed misregistration, mislocalization, and shortening of ICDs, findings similar to Xirp2−/− mice. Conclusions The synergistic effects of TNNT2 and XIRP2 mutations, resulting in perturbed sarcomeric force generation and transmission, respectively, would account for an early‐onset heart failure phenotype. Whereas the importance of Xin proteins in cardiac development has been well established in animal models, this study implicates XIRP2 as a novel modifier gene in the pathogenesis of DCM.
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Affiliation(s)
- Pamela A Long
- Mayo Graduate School, Molecular Pharmacology and Experimental Therapeutics Track, Mayo Clinic, Rochester, MN (P.A.L.) Cardiovascular Genetics Research Laboratory, Mayo Clinic, Rochester, MN (P.A.L., T.M.O.)
| | - Brandon T Larsen
- Department of Pathology, University of Arizona Medical Center, Tucson, AZ (B.T.L.)
| | - Jared M Evans
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN (J.M.E.)
| | - Timothy M Olson
- Cardiovascular Genetics Research Laboratory, Mayo Clinic, Rochester, MN (P.A.L., T.M.O.) Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN (T.M.O.) Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN (T.M.O.)
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Abstract
Recent advances have expanded our ability to conduct a comprehensive genetic evaluation for dilated cardiomyopathy (DCM). By evaluating recent literature, this review aims to bring the reader up-to-date on the genetic evaluation of DCM. Updated guidelines have been published. Mutations in BAG3, including a large deletion, were identified in 2 % of DCM. Truncating mutations in TTN were reported in 25 % of DCM. Two new genes have been reported with autosomal recessive DCM. These studies illustrate the role of improved technologies while raising the possibility of a complex genetic model for DCM. The inclusion of TTN has led to an increased genetic testing detection rate of 40 %. While our ability to identify disease-causing variants has increased, so has the identification of variants of unknown significance. A genetic evaluation for DCM must therefore address this complexity.
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Return of genetic results in the familial dilated cardiomyopathy research project. J Genet Couns 2012; 22:164-74. [PMID: 22886719 DOI: 10.1007/s10897-012-9532-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 07/20/2012] [Indexed: 01/06/2023]
Abstract
The goal of the Familial Dilated Cardiomyopathy (FDC) Research Project, initiated in 1993, has been to identify and characterize FDC genetic cause. All participating individuals have been consented for the return of genetic results, an important but challenging undertaking. Since the inception of the Project we have enrolled 606 probands, and 269 of these had 1670 family members also enrolled. Each subject was evaluated for idiopathic dilated cardiomyopathy (IDC) and pedigrees were categorized as familial or sporadic. The coding regions of 14 genes were resequenced in 311 to 324 probands in five studies. Ninety-two probands were found to carry nonsynonymous rare variants absent in controls, and with Clinical Laboratory Improvement Amendment of 1988 (CLIA) compliant protocols, relevant genetic results were returned to these probands and their consented relatives by study genetic counselors and physicians in 353 letters. In 10 of the 51 families that received results >1 year ago, at least 23 individuals underwent CLIA confirmation testing for their family's rare variant. Return of genetic results has been successfully undertaken in the FDC Research Project. This report describes the methods utilized in the process of returning research results. We use this information as a springboard for providing guidance to other genetic research groups and proposing future directions in this arena.
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Howarth FC, Qureshi MA, Hassan Z, Isaev D, Parekh K, John A, Oz M, Raza H, Adeghate E, Adrian TE. Contractility of ventricular myocytes is well preserved despite altered mechanisms of Ca2+ transport and a changing pattern of mRNA in aged type 2 Zucker diabetic fatty rat heart. Mol Cell Biochem 2011; 361:267-80. [PMID: 22009485 DOI: 10.1007/s11010-011-1112-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 10/07/2011] [Indexed: 02/07/2023]
Abstract
There has been a spectacular rise in the global prevalence of type 2 diabetes mellitus and cardiovascular complications are the major cause of morbidity and mortality in diabetic patients. The objective of the study was to investigate ventricular myocyte shortening, intracellular Ca(2+) signalling and expression of genes encoding cardiac muscle proteins in the aged Zucker diabetic fatty (ZDF) rat. There was a fourfold elevation in non-fasting blood glucose in ZDF rats (478.43 ± 29.22 mg/dl) compared to controls (108.22 ± 2.52 mg/dl). Amplitude of shortening, time to peak (TPK) and time to half (THALF) relaxation of shortening were unaltered in ZDF myocytes compared to age-matched controls. Amplitude and THALF decay of the Ca(2+) transient were unaltered; however, TPK Ca(2+) transient was prolonged in ZDF myocytes (70.0 ± 3.2 ms) compared to controls (58.4 ± 2.3 ms). Amplitude of the L-type Ca(2+) current was reduced across a wide range of test potentials (-30 to +40 mV) in ZDF myocytes compared to controls. Sarcoplasmic reticulum Ca(2+) content was unaltered in ZDF myocytes compared to controls. Expression of genes encoding cardiac muscle proteins, membrane Ca(2+) channels, and cell membrane ion transport and intracellular Ca(2+) transport proteins were variously altered. Myh6, Tnnt2, Cacna2d3, Slc9a1, and Atp2a2 were downregulated while Myl2, Cacna1g, Cacna1h, and Atp2a1 were upregulated in ZDF ventricle compared to controls. The results of this study have demonstrated that preserved ventricular myocyte shortening is associated with altered mechanisms of Ca(2+) transport and a changing pattern of genes encoding a variety of Ca(2+) signalling and cardiac muscle proteins in aged ZDF rat.
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Affiliation(s)
- F C Howarth
- Department of Physiology, Faculty of Medicine & Health Sciences, United Arab Emirates University, Al Ain, UAE.
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Burkett EL, Hershberger RE. Clinical and genetic issues in dilated cardiomyopathy: a review for genetics professionals. Genet Med 2011; 45:969-81. [PMID: 15808750 DOI: 10.1016/j.jacc.2004.11.066] [Citation(s) in RCA: 245] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 09/16/2004] [Accepted: 11/22/2004] [Indexed: 12/19/2022] Open
Abstract
Dilated cardiomyopathy (DCM), usually diagnosed as idiopathic dilated cardiomyopathy (IDC), has been shown to have a familial basis in 20-35% of cases. Genetic studies in familial dilated cardiomyopathy (FDC) have shown dramatic locus heterogeneity with mutations identified in >30 mostly autosomal genes showing primarily dominant transmission. Most mutations are private missense, nonsense or short insertion/deletions. Marked allelic heterogeneity is the rule. Although to date most DCM genetics fits into a Mendelian rare variant disease paradigm, this paradigm may be incomplete with only 30-35% of FDC genetic cause identified. Despite this incomplete knowledge, we predict that DCM genetics will become increasingly relevant for genetics and cardiovascular professionals. This is because DCM causes heart failure, a national epidemic, with considerable morbidity and mortality. The fact that early, even pre-symptomatic intervention can prevent or ameliorate DCM, coupled with more cost-effective genetic testing, will drive further progress in the field. Ongoing questions include: whether sporadic (IDC) disease has a genetic basis, and if so, how it differs from familial disease; which gene-specific or genetic pathways are most relevant; and whether other genetic mechanisms (e.g., DNA structural variants, epigenetics, mitochondrial mutations and others) are operative in DCM. We suggest that such new knowledge will lead to novel approaches to the prevention and treatment of DCM.
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Affiliation(s)
- Emily L Burkett
- Division of Cardiology, Department of Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OT 97239, USA
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Clinical and genetic issues in dilated cardiomyopathy: a review for genetics professionals. Genet Med 2011; 12:655-67. [PMID: 20864896 DOI: 10.1097/gim.0b013e3181f2481f] [Citation(s) in RCA: 177] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dilated cardiomyopathy (DCM), usually diagnosed as idiopathic dilated cardiomyopathy (IDC), has been shown to have a familial basis in 20-35% of cases. Genetic studies in familial dilated cardiomyopathy (FDC) have shown dramatic locus heterogeneity with mutations identified in >30 mostly autosomal genes showing primarily dominant transmission. Most mutations are private missense, nonsense or short insertion/deletions. Marked allelic heterogeneity is the rule. Although to date most DCM genetics fits into a Mendelian rare variant disease paradigm, this paradigm may be incomplete with only 30-35% of FDC genetic cause identified. Despite this incomplete knowledge, we predict that DCM genetics will become increasingly relevant for genetics and cardiovascular professionals. This is because DCM causes heart failure, a national epidemic, with considerable morbidity and mortality. The fact that early, even pre-symptomatic intervention can prevent or ameliorate DCM, coupled with more cost-effective genetic testing, will drive further progress in the field. Ongoing questions include: whether sporadic (IDC) disease has a genetic basis, and if so, how it differs from familial disease; which gene-specific or genetic pathways are most relevant; and whether other genetic mechanisms (e.g., DNA structural variants, epigenetics, mitochondrial mutations and others) are operative in DCM. We suggest that such new knowledge will lead to novel approaches to the prevention and treatment of DCM.
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