1
|
Theisen B, Holtz A, Rajagopalan V. Noncoding RNAs and Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes in Cardiac Arrhythmic Brugada Syndrome. Cells 2023; 12:2398. [PMID: 37830612 PMCID: PMC10571919 DOI: 10.3390/cells12192398] [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: 07/22/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/14/2023] Open
Abstract
Hundreds of thousands of people die each year as a result of sudden cardiac death, and many are due to heart rhythm disorders. One of the major causes of these arrhythmic events is Brugada syndrome, a cardiac channelopathy that results in abnormal cardiac conduction, severe life-threatening arrhythmias, and, on many occasions, death. This disorder has been associated with mutations and dysfunction of about two dozen genes; however, the majority of the patients do not have a definite cause for the diagnosis of Brugada Syndrome. The protein-coding genes represent only a very small fraction of the mammalian genome, and the majority of the noncoding regions of the genome are actively transcribed. Studies have shown that most of the loci associated with electrophysiological traits are located in noncoding regulatory regions and are expected to affect gene expression dosage and cardiac ion channel function. Noncoding RNAs serve an expanding number of regulatory and other functional roles within the cells, including but not limited to transcriptional, post-transcriptional, and epigenetic regulation. The major noncoding RNAs found in Brugada Syndrome include microRNAs; however, others such as long noncoding RNAs are also identified. They contribute to pathogenesis by interacting with ion channels and/or are detectable as clinical biomarkers. Stem cells have received significant attention in the recent past, and can be differentiated into many different cell types including those in the heart. In addition to contractile and relaxational properties, BrS-relevant electrophysiological phenotypes are also demonstrated in cardiomyocytes differentiated from stem cells induced from adult human cells. In this review, we discuss the current understanding of noncoding regions of the genome and their RNA biology in Brugada Syndrome. We also delve into the role of stem cells, especially human induced pluripotent stem cell-derived cardiac differentiated cells, in the investigation of Brugada syndrome in preclinical and clinical studies.
Collapse
Affiliation(s)
- Benjamin Theisen
- Department of Biomedical and Anatomical Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
| | - Austin Holtz
- Department of Biomedical and Anatomical Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
| | - Viswanathan Rajagopalan
- Department of Biomedical and Anatomical Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
- Arkansas Biosciences Institute, Jonesboro, AR 72401, USA
| |
Collapse
|
2
|
Popa IP, Șerban DN, Mărănducă MA, Șerban IL, Tamba BI, Tudorancea I. Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification. Int J Mol Sci 2023; 24:ijms24043328. [PMID: 36834739 PMCID: PMC9967917 DOI: 10.3390/ijms24043328] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/13/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Brugada syndrome (BrS) is a rare hereditary arrhythmia disorder, with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD) in young adults. BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match. Computational modelling, pre-clinical, and clinical research show that BrS molecular anomalies result in excitation wavelength (k) modifications, which eventually increase the risk of arrhythmia. Although a mutation in the SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5) gene was first reported almost two decades ago, BrS is still currently regarded as a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance. In spite of the extensive use of the next-generation sequencing (NGS) technique with high coverage, genetics remains unexplained in a number of clinically confirmed cases. Except for the SCN5A which encodes the cardiac sodium channel NaV1.5, susceptibility genes remain mostly unidentified. The predominance of cardiac transcription factor loci suggests that transcriptional regulation is essential to the Brugada syndrome's pathogenesis. It appears that BrS is a multifactorial disease, which is influenced by several loci, each of which is affected by the environment. The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification. The aim of this review is to summarize the latest findings addressing the genetic architecture of BrS and to provide novel perspectives into its molecular underpinnings and novel models of risk stratification.
Collapse
Affiliation(s)
- Irene Paula Popa
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
| | - Dragomir N. Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Minela Aida Mărănducă
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Ionela Lăcrămioara Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Bogdan Ionel Tamba
- Department of Pharmacology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
- Correspondence:
| | - Ionuț Tudorancea
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| |
Collapse
|
3
|
Abstract
Brugada syndrome is a heritable channelopathy characterized by a peculiar electrocardiogram (ECG) pattern and increased risk of cardiac arrhythmias and sudden death. The arrhythmias originate because of an imbalance between the repolarizing and depolarizing currents that modulate the cardiac action potential. Even if an overt structural cardiomyopathy is not typical of Brugada syndrome, fibrosis and structural changes in the right ventricle contribute to a conduction slowing, which ultimately facilitates ventricular arrhythmias. Currently, Mendelian autosomal dominant transmission is detected in less than 25% of all clinical confirmed cases. Although 23 genes have been associated with the condition, only SCN5A, encoding the cardiac sodium channel, is considered clinically actionable and disease causing. The limited monogenic inheritance has pointed toward new perspectives on the possible complex genetic architecture of the disease, involving polygenic inheritance and a polygenic risk score that can influence penetrance and risk stratification. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Marina Cerrone
- Leon H. Charney Division of Cardiology, Grossman School of Medicine, New York University, New York, NY, USA;
| | - Sarah Costa
- Department of Internal Medicine, Kantonsspital Baden, Baden, Switzerland
| | - Mario Delmar
- Leon H. Charney Division of Cardiology, Grossman School of Medicine, New York University, New York, NY, USA;
| |
Collapse
|
4
|
Martínez-Campelo L, Cruz R, Blanco-Verea A, Moscoso I, Ramos-Luis E, Lage R, Álvarez-Barredo M, Sabater-Molina M, Peñafiel-Verdú P, Jiménez-Jáimez J, Rodríguez-Mañero M, Brion M. Searching for genetic modulators of the phenotypic heterogeneity in Brugada syndrome. PLoS One 2022; 17:e0263469. [PMID: 35231055 PMCID: PMC8887717 DOI: 10.1371/journal.pone.0263469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 01/20/2022] [Indexed: 11/19/2022] Open
Abstract
In Brugada syndrome, even within the same family where all affected individuals share the same mutation, phenotypic variation is prominent, with variable penetrance and expressivity, presenting different degrees of involvement. It is difficult to establish a direct correlation between genotype and phenotype to predict prognosis in complications and risk of sudden death. The factors that modulate this inter- and intra-familial phenotypic variability remain to be determined. With the intention of testing whether other genetic factors, in addition to the causal mutation in SCN5A, may have a modulating effect on the Brugada phenotype and the risk of sudden death, we have studied 8 families with a causal variant in SCN5A with at least two affected individuals, one of whom has suffered cardiac arrest or sudden death. Whole exome sequencing was performed looking for additional variants that modify the phenotype and allow us to predict a better or worse prognosis for the evolution of the disease. The results did not show any clear genetic modifier; nevertheless, highlight the possible implication of the cholesterol and fibrosis pathways, as well as the circadian rhythm, as possible modulators of Brugada syndrome phenotype.
Collapse
Affiliation(s)
- Laura Martínez-Campelo
- Cardiovascular Genetics, Santiago de Compostela Health Research Institute, Santiago de Compostela, Spain
- Genomic Medicine Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Raquel Cruz
- Genomic Medicine Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
- CIBER of Rare Diseases, Carlos III Health Institute, Madrid, Spain
| | - Alejandro Blanco-Verea
- Cardiovascular Genetics, Santiago de Compostela Health Research Institute, Santiago de Compostela, Spain
- Genomic Medicine Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Isabel Moscoso
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Cardiology Group, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Eva Ramos-Luis
- Cardiovascular Genetics, Santiago de Compostela Health Research Institute, Santiago de Compostela, Spain
- Genomic Medicine Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Ricardo Lage
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Cardiology Group, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - María Álvarez-Barredo
- Cardiovascular Genetics, Santiago de Compostela Health Research Institute, Santiago de Compostela, Spain
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
| | - María Sabater-Molina
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Cardiogenetics Laboratory, Murcian Institute for Biosanitary Research, Cardiology Service, Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - Pablo Peñafiel-Verdú
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Cardiogenetics Laboratory, Murcian Institute for Biosanitary Research, Cardiology Service, Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - Juan Jiménez-Jáimez
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Arrhythmia Unit, Virgen de las Nieves University Hospital, Granada, Spain
| | - Moisés Rodríguez-Mañero
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Cardiology Service, Santiago de Compostela University Hospital, Santiago de Compostela, Spain
| | - María Brion
- Cardiovascular Genetics, Santiago de Compostela Health Research Institute, Santiago de Compostela, Spain
- Genomic Medicine Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
- Cardiovascular CIBER, Carlos III Health Institute, Madrid, Spain
- Family Heart Disease Unit, Cardiology Service, Santiago de Compostela University Hospital, Santiago de Compostela, Spain
| |
Collapse
|
5
|
Daimi H, Lozano-Velasco E, Aranega A, Franco D. Genomic and Non-Genomic Regulatory Mechanisms of the Cardiac Sodium Channel in Cardiac Arrhythmias. Int J Mol Sci 2022; 23:1381. [PMID: 35163304 PMCID: PMC8835759 DOI: 10.3390/ijms23031381] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/30/2021] [Accepted: 01/06/2022] [Indexed: 12/19/2022] Open
Abstract
Nav1.5 is the predominant cardiac sodium channel subtype, encoded by the SCN5A gene, which is involved in the initiation and conduction of action potentials throughout the heart. Along its biosynthesis process, Nav1.5 undergoes strict genomic and non-genomic regulatory and quality control steps that allow only newly synthesized channels to reach their final membrane destination and carry out their electrophysiological role. These regulatory pathways are ensured by distinct interacting proteins that accompany the nascent Nav1.5 protein along with different subcellular organelles. Defects on a large number of these pathways have a tremendous impact on Nav1.5 functionality and are thus intimately linked to cardiac arrhythmias. In the present review, we provide current state-of-the-art information on the molecular events that regulate SCN5A/Nav1.5 and the cardiac channelopathies associated with defects in these pathways.
Collapse
Affiliation(s)
- Houria Daimi
- Biochemistry and Molecular Biology Laboratory, Faculty of Pharmacy, University of Monastir, Monastir 5000, Tunisia
| | - Estefanía Lozano-Velasco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Amelia Aranega
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Diego Franco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| |
Collapse
|
6
|
Man JCK, Bosada FM, Scholman KT, Offerhaus JA, Walsh R, van Duijvenboden K, van Eif VWW, Bezzina CR, Verkerk AO, Boukens BJ, Barnett P, Christoffels VM. Variant Intronic Enhancer Controls SCN10A-short Expression and Heart Conduction. Circulation 2021; 144:229-242. [PMID: 33910361 DOI: 10.1161/circulationaha.121.054083] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Genetic variants in SCN10A, encoding the neuronal voltage-gated sodium channel NaV1.8, are strongly associated with atrial fibrillation, Brugada syndrome, cardiac conduction velocities, and heart rate. The cardiac function of SCN10A has not been resolved, however, and diverging mechanisms have been proposed. Here, we investigated the cardiac expression of SCN10A and the function of a variant-sensitive intronic enhancer previously linked to the regulation of SCN5A, encoding the major essential cardiac sodium channel NaV1.5. METHODS The expression of SCN10A was investigated in mouse and human hearts. With the use of CRISPR/Cas9 genome editing, the mouse intronic enhancer was disrupted, and mutant mice were characterized by transcriptomic and electrophysiological analyses. The association of genetic variants at SCN5A-SCN10A enhancer regions and gene expression were evaluated by genome-wide association studies single-nucleotide polymorphism mapping and expression quantitative trait loci analysis. RESULTS We found that cardiomyocytes of the atria, sinoatrial node, and ventricular conduction system express a short transcript comprising the last 7 exons of the gene (Scn10a-short). Transcription occurs from an intronic enhancer-promoter complex, whereas full-length Scn10a transcript was undetectable in the human and mouse heart. Expression quantitative trait loci analysis revealed that the genetic variants in linkage disequilibrium with genetic variant rs6801957 in the intronic enhancer associate with SCN10A transcript levels in the heart. Genetic modification of the enhancer in the mouse genome led to reduced cardiac Scn10a-short expression in atria and ventricles, reduced cardiac sodium current in atrial cardiomyocytes, atrial conduction slowing and arrhythmia, whereas the expression of Scn5a, the presumed enhancer target gene, remained unaffected. In patch-clamp transfection experiments, expression of Scn10a-short-encoded NaV1.8-short increased NaV1.5-mediated sodium current. We propose that noncoding genetic variation modulates transcriptional regulation of Scn10a-short in cardiomyocytes that impacts NaV1.5-mediated sodium current and heart rhythm. CONCLUSIONS Genetic variants in and around SCN10A modulate enhancer function and expression of a cardiac-specific SCN10A-short transcript. We propose that noncoding genetic variation modulates transcriptional regulation of a functional C-terminal portion of NaV1.8 in cardiomyocytes that impacts on NaV1.5 function, cardiac conduction velocities, and arrhythmia susceptibility.
Collapse
Affiliation(s)
- Joyce C K Man
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Fernanda M Bosada
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Koen T Scholman
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Joost A Offerhaus
- Department of Experimental Cardiology (J.A.O., R.W., C.R.B., A.O.V., B.J.B.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Roddy Walsh
- Department of Experimental Cardiology (J.A.O., R.W., C.R.B., A.O.V., B.J.B.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Karel van Duijvenboden
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Vincent W W van Eif
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Connie R Bezzina
- Department of Experimental Cardiology (J.A.O., R.W., C.R.B., A.O.V., B.J.B.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Arie O Verkerk
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Department of Experimental Cardiology (J.A.O., R.W., C.R.B., A.O.V., B.J.B.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Department of Experimental Cardiology (J.A.O., R.W., C.R.B., A.O.V., B.J.B.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Phil Barnett
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam Reproduction and Development (J.C.K.M., F.M.B., K.T.S., K.v.D., V.W.W.v.E., A.O.V., B.J.B., P.B., V.M.C.), Amsterdam UMC, University of Amsterdam, location AMC, The Netherlands
| |
Collapse
|
7
|
Monasky MM, Micaglio E, Locati ET, Pappone C. Evaluating the Use of Genetics in Brugada Syndrome Risk Stratification. Front Cardiovasc Med 2021; 8:652027. [PMID: 33969014 PMCID: PMC8096997 DOI: 10.3389/fcvm.2021.652027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/24/2021] [Indexed: 12/19/2022] Open
Abstract
The evolution of the current dogma surrounding Brugada syndrome (BrS) has led to a significant debate about the real usefulness of genetic testing in this syndrome. Since BrS is defined by a particular electrocardiogram (ECG) pattern, after ruling out certain possible causes, this disease has come to be defined more for what it is not than for what it is. Extensive research is required to understand the effects of specific individual variants, including modifiers, rather than necessarily grouping together, for example, “all SCN5A variants” when trying to determine genotype-phenotype relationships, because not all variants within a particular gene act similarly. Genetic testing, including whole exome or whole genome testing, and family segregation analysis should always be performed when possible, as this is necessary to advance our understanding of the genetics of this condition. All considered, BrS should no longer be considered a pure autosomal dominant disorder, but an oligogenic condition. Less common patterns of inheritance, such as recessive, X–linked, or mitochondrial may exist. Genetic testing, in our opinion, should not be used for diagnostic purposes. However, variants in SCN5A can have a prognostic value. Patients should be diagnosed and treated per the current guidelines, after an arrhythmologic examination, based on the presence of the specific BrS ECG pattern. The genotype characterization should come in a second stage, particularly in order to guide the familial diagnostic work-up. In families in which an SCN5A pathogenic variant is found, genetic testing could possibly contribute to the prognostic risk stratification.
Collapse
Affiliation(s)
| | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Emanuela T Locati
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| |
Collapse
|
8
|
Elevated EZH2 in ischemic heart disease epigenetically mediates suppression of Na V1.5 expression. J Mol Cell Cardiol 2020; 153:95-103. [PMID: 33370552 DOI: 10.1016/j.yjmcc.2020.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/16/2020] [Accepted: 12/20/2020] [Indexed: 12/19/2022]
Abstract
Suppression of the cardiac sodium channel NaV1.5 leads to fatal arrhythmias in ischemic heart disease (IHD). However, the transcriptional regulation of NaV1.5 in cardiac ischemia is still unclear. Our studies are aimed to investigate the expression of enhancer of zeste homolog 2 (EZH2) in IHD and regulation of cardiac NaV1.5 expression by EZH2. Human heart tissue was obtained from IHD and non-failing heart (NFH) patients; mouse heart tissue was obtained from the peri-infarct zone of hearts with myocardial infarction (MI) and hearts with a sham procedure. Protein and mRNA expression were measured by immunoblotting, immunostaining, and qRT-PCR. Protein-DNA binding and promoter activity were analyzed by ChIP-qPCR and luciferase assays, respectively. Na+ channel activity was assessed by whole-cell patch clamp recordings. EZH2 and H3K27me3 were increased while NaV1.5 expression was reduced in IHD hearts and in mouse MI hearts compared to the controls. Reduced NaV1.5 and increased EZH2 mRNA levels were observed in mouse MI hearts. A selective EZH2 inhibitor, GSK126 decreased H3K27me3 and elevated NaV1.5 in HL-1 cells. Silencing of EZH2 expression decreased H3K27me3 and increased NaV1.5 in these cells. EZH2 and H3K27me3 were enriched in the promoter regions of Scn5a and were decreased by treatment with EZH2 siRNA. GSK126 inhibited the enrichment of H3K27me3 in the Scn5a promoter and enhanced Scn5a transcriptional activity. GSK126 significantly increased Na+ channel activity. Taken together, EZH2 is increased in ischemic hearts and epigenetically suppresses Scn5a transcription by H3K27me3, leading to decreased NaV1.5 expression and Na+ channel activity underlying the pathogenesis of arrhythmias.
Collapse
|
9
|
Pérez-Agustín A, Pinsach-Abuin M, Pagans S. Role of Non-Coding Variants in Brugada Syndrome. Int J Mol Sci 2020; 21:E8556. [PMID: 33202810 PMCID: PMC7698069 DOI: 10.3390/ijms21228556] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022] Open
Abstract
Brugada syndrome (BrS) is an inherited electrical heart disease associated with a high risk of sudden cardiac death (SCD). The genetic characterization of BrS has always been challenging. Although several cardiac ion channel genes have been associated with BrS, SCN5A is the only gene that presents definitive evidence for causality to be used for clinical diagnosis of BrS. However, more than 65% of diagnosed cases cannot be explained by variants in SCN5A or other genes. Therefore, in an important number of BrS cases, the underlying mechanisms are still elusive. Common variants, mostly located in non-coding regions, have emerged as potential modulators of the disease by affecting different regulatory mechanisms, including transcription factors (TFs), three-dimensional organization of the genome, or non-coding RNAs (ncRNAs). These common variants have been hypothesized to modulate the interindividual susceptibility of the disease, which could explain incomplete penetrance of BrS observed within families. Altogether, the study of both common and rare variants in parallel is becoming increasingly important to better understand the genetic basis underlying BrS. In this review, we aim to describe the challenges of studying non-coding variants associated with disease, re-examine the studies that have linked non-coding variants with BrS, and provide further evidence for the relevance of regulatory elements in understanding this cardiac disorder.
Collapse
Affiliation(s)
- Adrian Pérez-Agustín
- Department of Medical Sciences, School of Medicine, University of Girona, 17003 Girona, Spain;
- Biomedical Research Institute of Girona, 17190 Salt, Spain;
| | | | - Sara Pagans
- Department of Medical Sciences, School of Medicine, University of Girona, 17003 Girona, Spain;
- Biomedical Research Institute of Girona, 17190 Salt, Spain;
| |
Collapse
|
10
|
Campuzano O, Sarquella-Brugada G, Cesar S, Arbelo E, Brugada J, Brugada R. Update on Genetic Basis of Brugada Syndrome: Monogenic, Polygenic or Oligogenic? Int J Mol Sci 2020; 21:ijms21197155. [PMID: 32998306 PMCID: PMC7582739 DOI: 10.3390/ijms21197155] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Brugada syndrome is a rare inherited arrhythmogenic disease leading to ventricular fibrillation and high risk of sudden death. In 1998, this syndrome was linked with a genetic variant with an autosomal dominant pattern of inheritance. To date, rare variants identified in more than 40 genes have been potentially associated with this disease. Variants in regulatory regions, combinations of common variants and other genetic alterations are also proposed as potential origins of Brugada syndrome, suggesting a polygenic or oligogenic inheritance pattern. However, most of these genetic alterations remain of questionable causality; indeed, rare pathogenic variants in the SCN5A gene are the only established cause of Brugada syndrome. Comprehensive analysis of all reported genetic alterations identified the origin of disease in no more than 40% of diagnosed cases. Therefore, identifying the cause of this rare arrhythmogenic disease in the many families without a genetic diagnosis is a major current challenge in Brugada syndrome. Additional challenges are interpretation/classification of variants and translation of genetic data into clinical practice. Further studies focused on unraveling the pathophysiological mechanisms underlying the disease are needed. Here we provide an update on the genetic basis of Brugada syndrome.
Collapse
Affiliation(s)
- Oscar Campuzano
- Cardiovascular Genetics Centre, University of Girona-IDIBGI, 17190 Girona, Spain
- Medical Science Department, School of Medicine, University of Girona, 17003 Girona, Spain;
- Centro Investigación Biomédica en Red: Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Correspondence: (O.C.); (R.B.)
| | - Georgia Sarquella-Brugada
- Medical Science Department, School of Medicine, University of Girona, 17003 Girona, Spain;
- Arrhythmia Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain;
| | - Sergi Cesar
- Arrhythmia Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain;
| | - Elena Arbelo
- Centro Investigación Biomédica en Red: Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Arrhythmia Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain;
| | - Josep Brugada
- Centro Investigación Biomédica en Red: Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Arrhythmia Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain;
- Arrhythmia Section, Cardiovascular Institute, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Centre, University of Girona-IDIBGI, 17190 Girona, Spain
- Medical Science Department, School of Medicine, University of Girona, 17003 Girona, Spain;
- Centro Investigación Biomédica en Red: Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (J.B.)
- Familial Cardiomyopathies Unit, Hospital Josep Trueta de Girona, 17007 Girona, Spain
- Correspondence: (O.C.); (R.B.)
| |
Collapse
|
11
|
Novel SCN5A p.V1429M Variant Segregation in a Family with Brugada Syndrome. Int J Mol Sci 2020; 21:ijms21165902. [PMID: 32824506 PMCID: PMC7460631 DOI: 10.3390/ijms21165902] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 01/10/2023] Open
Abstract
Brugada syndrome (BrS) is diagnosed by the presence of an elevated ST-segment and can result in sudden cardiac death. The most commonly found mutated gene is SCN5A, which some argue is the only gene that has been definitively confirmed to cause BrS, while the potential causative effect of other genes is still under debate. While the issue of BrS genetics is currently a hot topic, current knowledge is not able to result in molecular confirmation of over half of BrS cases. Therefore, it is difficult to develop research models with wide potential. Instead, the clinical genetics first need to be better understood. In this study, we provide crucial human data on the novel heterozygous variant NM_198056.2:c.4285G>A (p.Val1429Met) in the SCN5A gene, and demonstrate its segregation with BrS, suggesting a pathogenic effect. These results provide the first disease association with this variant and are crucial clinical data to communicate to basic scientists, who could perform functional studies to better understand the molecular effects of this clinically-relevant variant in BrS.
Collapse
|
12
|
Xiao QY, Fang XC, Li XQ, Fei GJ. Ethnic differences in genetic polymorphism associated with irritable bowel syndrome. World J Gastroenterol 2020; 26:2049-2063. [PMID: 32536774 PMCID: PMC7267697 DOI: 10.3748/wjg.v26.i17.2049] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/25/2020] [Accepted: 04/04/2020] [Indexed: 02/06/2023] Open
Abstract
Genetic polymorphism is associated with irritable bowel syndrome (IBS) in terms of susceptibility and clinical manifestations. Previous studies have shown that genetic polymorphism might play a key role in the onset and progression of IBS by modulating components of its pathogenesis such as the gut-brain axis, gastrointestinal motility, inflammatory activity, and immune status. Although underlying pathophysiological mechanisms have not been fully clarified, the potential ethnic differences that are present in worldwide genetic studies of IBS deserve attention. This review surveyed numerous studies focusing on IBS-associated single nucleotide polymorphisms, and investigated the ethnic disparities revealed by them. The results demonstrate the need for more attention on ethnic factors in IBS-related genetic studies. Taking ethnic backgrounds into accounts and placing emphasis on disparities potentially ascribed to ethnicity could help lay a solid and generalized foundation for transcultural, multi-ethnic, or secondary analyses in IBS, for example, a meta-analysis. Broader genetic studies considering ethnic factors are greatly needed to obtain a better understanding of the pathophysiological mechanisms of IBS and to improve the prevention, intervention, and treatment of this disease.
Collapse
Affiliation(s)
- Qi-Yun Xiao
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Xiu-Cai Fang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Xiao-Qing Li
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Gui-Jun Fei
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| |
Collapse
|
13
|
Shimoyama T, Hayashi H, Suzuki F, Nishiyama Y, Miyamoto Y, Aiba T, Shimizu W, Kimura K. Idiopathic ventricular fibrillation and the V1764fsX1786 frameshift mutation of the SCN5A gene in a myotonic dystrophy type 1 patient. J Clin Neurosci 2020; 74:242-244. [DOI: 10.1016/j.jocn.2020.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/08/2020] [Indexed: 10/25/2022]
|
14
|
Monasky MM, Micaglio E, Ciconte G, Pappone C. Brugada Syndrome: Oligogenic or Mendelian Disease? Int J Mol Sci 2020; 21:ijms21051687. [PMID: 32121523 PMCID: PMC7084676 DOI: 10.3390/ijms21051687] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 02/06/2023] Open
Abstract
Brugada syndrome (BrS) is diagnosed by a coved-type ST-segment elevation in the right precordial leads on the electrocardiogram (ECG), and it is associated with an increased risk of sudden cardiac death (SCD) compared to the general population. Although BrS is considered a genetic disease, its molecular mechanism remains elusive in about 70-85% of clinically-confirmed cases. Variants occurring in at least 26 different genes have been previously considered causative, although the causative effect of all but the SCN5A gene has been recently challenged, due to the lack of systematic, evidence-based evaluations, such as a variant's frequency among the general population, family segregation analyses, and functional studies. Also, variants within a particular gene can be associated with an array of different phenotypes, even within the same family, preventing a clear genotype-phenotype correlation. Moreover, an emerging concept is that a single mutation may not be enough to cause the BrS phenotype, due to the increasing number of common variants now thought to be clinically relevant. Thus, not only the complete list of genes causative of the BrS phenotype remains to be determined, but also the interplay between rare and common multiple variants. This is particularly true for some common polymorphisms whose roles have been recently re-evaluated by outstanding works, including considering for the first time ever a polygenic risk score derived from the heterozygous state for both common and rare variants. The more common a certain variant is, the less impact this variant might have on heart function. We are aware that further studies are warranted to validate a polygenic risk score, because there is no mutated gene that connects all, or even a majority, of BrS cases. For the same reason, it is currently impossible to create animal and cell line genetic models that represent all BrS cases, which would enable the expansion of studies of this syndrome. Thus, the best model at this point is the human patient population. Further studies should first aim to uncover genetic variants within individuals, as well as to collect family segregation data to identify potential genetic causes of BrS.
Collapse
Affiliation(s)
| | | | | | - Carlo Pappone
- Correspondence: ; Tel.: +39-0252-774260; Fax: +39-0252-774306
| |
Collapse
|
15
|
Micaglio E, Monasky MM, Resta N, Bagnulo R, Ciconte G, Gianelli L, Locati ET, Vicedomini G, Borrelli V, Ghiroldi A, Anastasia L, Benedetti S, Di Resta C, Ferrari M, Pappone C. Novel SCN5A p.W697X Nonsense Mutation Segregation in a Family with Brugada Syndrome. Int J Mol Sci 2019; 20:ijms20194920. [PMID: 31590245 PMCID: PMC6801452 DOI: 10.3390/ijms20194920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 01/05/2023] Open
Abstract
Brugada syndrome (BrS) is marked by an elevated ST-segment elevation and increased risk of sudden cardiac death. Variants in the SCN5A gene are considered to be molecular confirmation of the syndrome in about one third of cases, while the genetics remain a mystery in about half of the cases, with the remaining cases being attributed to variants in any of a number of genes. Before research models can be developed, it is imperative to understand the genetics in patients. Even data from humans is complicated, since variants in the most common gene in BrS, SCN5A, are associated with a number of pathologies, or could even be considered benign, depending on the variant. Here, we provide crucial human data on a novel NM_198056.2:c.2091G>A (p.Trp697X) point-nonsense heterozygous variant in the SCN5A gene, as well as its segregation with BrS. The results herein suggest a pathogenic effect of this variant. These results could be used as a stepping stone for functional studies to better understand the molecular effects of this variant in BrS.
Collapse
Affiliation(s)
- Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Michelle M. Monasky
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Nicoletta Resta
- Medical Genetics Unit, Department of Biomedical Sciences and Human Oncology, “Aldo Moro” University of Bari, Policlinico Hospital, 70121 Bari, Italy; (N.R.); (R.B.)
| | - Rosanna Bagnulo
- Medical Genetics Unit, Department of Biomedical Sciences and Human Oncology, “Aldo Moro” University of Bari, Policlinico Hospital, 70121 Bari, Italy; (N.R.); (R.B.)
| | - Giuseppe Ciconte
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Luigi Gianelli
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Emanuela T. Locati
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Gabriele Vicedomini
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Valeria Borrelli
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
| | - Andrea Ghiroldi
- Stem Cells for Tissue Engineering Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy; (A.G.); (L.A.)
| | - Luigi Anastasia
- Stem Cells for Tissue Engineering Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy; (A.G.); (L.A.)
- Department of Biomedical Sciences for Health, University of Milan, 20122 Milan, Italy
| | - Sara Benedetti
- Laboratory of Clinical Molecular Biology and Cytogenetics, Division of Genetics and Cellular Biology, IRCCS San Raffaele Hospital, 20132 Milan, Italy; (S.B.); (M.F.)
| | - Chiara Di Resta
- Genomic Unit for the Diagnosis of Human Pathologies, Division of Genetics and Cellular Biology, IRCCS San Raffaele Hospital, 20132 Milan, Italy;
- Vita-Salute San Raffaele University, 20132 Milan, Italy
| | - Maurizio Ferrari
- Laboratory of Clinical Molecular Biology and Cytogenetics, Division of Genetics and Cellular Biology, IRCCS San Raffaele Hospital, 20132 Milan, Italy; (S.B.); (M.F.)
- Genomic Unit for the Diagnosis of Human Pathologies, Division of Genetics and Cellular Biology, IRCCS San Raffaele Hospital, 20132 Milan, Italy;
- Vita-Salute San Raffaele University, 20132 Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy (M.M.M.); (G.C.); (L.G.); (E.T.L.); (G.V.); (V.B.)
- Correspondence: ; Tel.: +39-0252774260
| |
Collapse
|
16
|
Whole genome and transcriptome sequencing of post-mortem cardiac tissues from sudden cardiac death victims identifies a gene regulatory variant in NEXN. Int J Legal Med 2019; 133:1699-1709. [PMID: 31392414 DOI: 10.1007/s00414-019-02127-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/11/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Sudden cardiac death (SCD) is a major public health problem and constitutes a diagnostic and preventive challenge in forensic pathology, especially for cases with structural normal hearts at autopsy, so-called sudden arrhythmic death syndrome (SADS). The identification of new genetic risk factors that predispose to SADS is important, because they may contribute to establish the diagnosis and increase the understanding of disease pathways underlying SADS. Pathogenic mutations in the protein coding regions of cardiac genes were found in relation to SADS. However, much remains unknown about variants in non-coding regions of the genome. METHODS AND RESULTS In this study, we explored the potential of whole genome sequencing (WGS) and whole transcriptome sequencing (WTS) to find DNA variants in SCD victims with structural normal hearts. With focus on the non-coding regulatory regions, we re-examined a cohort of 13 SADS and sudden unexplained death in infancy (SUDI) victims without disease causing DNA variants in recognized cardiac genes. The genetic re-examination of DNA was carried out using frozen tissue samples and WTS was carried out using five distinct formalin fixed and paraffin embedded (FFPE) cardiac tissue samples from each individual, including anterior and posterior walls of the left ventricle, ventricular papillary muscle, septum, and the right ventricle. We identified 23 candidate variants in regulatory sequences of cardiac genes, including a variant in the promotor region of NEXN, c.-194A>G, that was found to be statistically significantly (p < 0.05) associated with decreased expression of NEXN and cardiac hypertrophy. CONCLUSION With the use of post-mortem FFPE tissues, we highlight the potential of using WTS investigations and compare gene expression levels with DNA variation in regulatory non-coding regions of the genome for a better understanding of the genetics of cardiac diseases leading to SCD.
Collapse
|
17
|
Holistic Approach to Determine Cause of Autopsy-Negative Sudden Natural Death. J Am Coll Cardiol 2019; 69:2146-2148. [PMID: 28449775 DOI: 10.1016/j.jacc.2017.01.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 01/20/2017] [Indexed: 12/20/2022]
|
18
|
Aiba T. Recent understanding of clinical sequencing and gene-based risk stratification in inherited primary arrhythmia syndrome. J Cardiol 2019; 73:335-342. [PMID: 30910390 DOI: 10.1016/j.jjcc.2019.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 01/07/2019] [Indexed: 12/19/2022]
Abstract
Inherited primary arrhythmia syndromes (IPAS) may result in ventricular tachycardia or ventricular fibrillation by some genetic disorders, leading to sudden cardiac death. IPAS are also called "channelopathies" since many of these are caused by an abnormality in myocardial ion channels. Congenital long-QT syndrome (LQTS) is the most well documented IPAS, which may be seen in 0.1% of the general population. More than 15 disease-causing genes have been identified in almost 70% of LQTS patients and genetic testing is well applied to not only clinical diagnosis but also risk stratification and gene-based therapeutic strategy for each person with LQTS. Thus, in LQTS, gene-based personalized medicine can be realized. Unlike the LQTS, genetic testing for the Brugada syndrome (BrS) is still controversial since only 20% of patients can be identified with the causing gene mutations, most of which are in SCN5A. Furthermore, even in the SCN5A mutation-positive carriers, their phenotypes are not completely consistent with BrS, but may cause other IPAS including LQTS, cardiac conduction defect, sick sinus syndrome, and dilated cardiomyopathy. On the other hand, a recent Japanese BrS registry demonstrated that the pore-region mutations in SCN5A are significantly associated with a risk of lethal cardiac events. Furthermore, a genome-wide association study revealed that a common variant in SCN10A or HEY2 in addition to SCN5A is associated with BrS, thus, BrS may not be a monogenic Mendelian disease but probably an oligogenic disease. The purpose of this review is to describe the basic genetic and pathophysiological findings of the IPAS, particularly LQTS and Brugada syndrome, and to outline a rational approach to genetic testing, management, and family screening.
Collapse
Affiliation(s)
- Takeshi Aiba
- Department of Advanced Arrhythmia and Translational Medical Science, National Cerebral and Cardiovascular Center, Osaka, Japan.
| |
Collapse
|
19
|
Hayashi H, Sumiyoshi M, Nakazato Y, Daida H. Brugada syndrome and sinus node dysfunction. J Arrhythm 2018; 34:216-221. [PMID: 29951135 PMCID: PMC6009769 DOI: 10.1002/joa3.12046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/12/2018] [Indexed: 12/19/2022] Open
Abstract
Brugada syndrome (BrS) is a well-known catastrophic disease first reported in 1992 by the Brugada brothers. Ventricular fibrillation (VF) is an essential arrhythmia in BrS. An association between BrS and atrial tachyarrhythmias is not uncommon. However, sinus node dysfunction (SND) associated with BrS has not been well discussed. In this review, we focus on the association between BrS and SND. Based on previous reports describing clinical, epidemiological, and genetic evidence, SND is not a rare concomitant disorder in BrS. BrS may be a multiple conduction or arrhythmogenic disorder including not only the His-Purkinje system and right ventricle, but also the sinus node and atrium, derived from ion channel mutations.
Collapse
Affiliation(s)
- Hidemori Hayashi
- Department of Cardiovascular MedicineJuntendo University School of MedicineTokyoJapan
| | | | - Yuji Nakazato
- Department of CardiologyJuntendo University Urayasu HospitalUrayasuJapan
| | - Hiroyuki Daida
- Department of Cardiovascular MedicineJuntendo University School of MedicineTokyoJapan
| |
Collapse
|