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Møller Nielsen AK, Dehn AM, Hjortdal V, Larsen LA. TBX5 variants and cardiac phenotype: A systematic review of the literature and a novel variant. Eur J Med Genet 2024; 68:104920. [PMID: 38336121 DOI: 10.1016/j.ejmg.2024.104920] [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: 05/14/2023] [Revised: 12/07/2023] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
T-Box Transcription Factor 5 (TBX5) variants are associated with Holt-Oram syndrome. Holt-Oram syndrome display phenotypic variability, regarding upper limb defects, congenital heart defects, and arrhythmias. To investigate the genotype-phenotype relationship between TBX5 variants and cardiac disease, we performed a systematic review of the literature. Through the systematic review we identified 108 variants in TBX5 associated with a cardiac phenotype in 277 patients. Arrhythmias were more frequent in patients with a missense variant (48% vs 30%, p = 0.009) and upper limb abnormalities were more frequent in patients with protein-truncating variants (85% vs 64%, p = 0.0008). We found clustering of missense variants in the T-box domain. Furthermore, we present a family with atrial septal defects. By whole exome sequencing, we identified a novel missense variant p.Phe232Leu in TBX5. The cardiac phenotype included atrial septal defect, arrhythmias, heart failure, and dilated cardiomyopathy. Clinical examination revealed subtle upper limb abnormalities. Thus, the family corresponds to the diagnostic criteria of Holt-Oram syndrome. We provide an overview of cardiac phenotypes associated with TBX5 variants and show an increased risk of arrhythmias associated to missense variants compared to protein-truncating variants. We report a novel missense variant in TBX5 in a family with an atypical Holt-Oram syndrome phenotype.
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Affiliation(s)
- Anne Kathrine Møller Nielsen
- Department of Cardiothoracic Surgery, Rigshospitalet, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Anna Maria Dehn
- Department of Cardiothoracic Surgery, Rigshospitalet, Denmark
| | - Vibeke Hjortdal
- Department of Cardiothoracic Surgery, Rigshospitalet, Denmark
| | - Lars Allan Larsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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2
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Shafi O, Siddiqui G, Jaffry HA. The benign nature and rare occurrence of cardiac myxoma as a possible consequence of the limited cardiac proliferative/ regenerative potential: a systematic review. BMC Cancer 2023; 23:1245. [PMID: 38110859 PMCID: PMC10726542 DOI: 10.1186/s12885-023-11723-3] [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: 08/08/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023] Open
Abstract
BACKGROUND Cardiac Myxoma is a primary tumor of heart. Its origins, rarity of the occurrence of primary cardiac tumors and how it may be related to limited cardiac regenerative potential, are not yet entirely known. This study investigates the key cardiac genes/ transcription factors (TFs) and signaling pathways to understand these important questions. METHODS Databases including PubMed, MEDLINE, and Google Scholar were searched for published articles without any date restrictions, involving cardiac myxoma, cardiac genes/TFs/signaling pathways and their roles in cardiogenesis, proliferation, differentiation, key interactions and tumorigenesis, with focus on cardiomyocytes. RESULTS The cardiac genetic landscape is governed by a very tight control between proliferation and differentiation-related genes/TFs/pathways. Cardiac myxoma originates possibly as a consequence of dysregulations in the gene expression of differentiation regulators including Tbx5, GATA4, HAND1/2, MYOCD, HOPX, BMPs. Such dysregulations switch the expression of cardiomyocytes into progenitor-like state in cardiac myxoma development by dysregulating Isl1, Baf60 complex, Wnt, FGF, Notch, Mef2c and others. The Nkx2-5 and MSX2 contribute predominantly to both proliferation and differentiation of Cardiac Progenitor Cells (CPCs), may possibly serve roles based on the microenvironment and the direction of cell circuitry in cardiac tumorigenesis. The Nkx2-5 in cardiac myxoma may serve to limit progression of tumorigenesis as it has massive control over the proliferation of CPCs. The cardiac cell type-specific genetic programming plays governing role in controlling the tumorigenesis and regenerative potential. CONCLUSION The cardiomyocytes have very limited proliferative and regenerative potential. They survive for long periods of time and tightly maintain the gene expression of differentiation genes such as Tbx5, GATA4 that interact with tumor suppressors (TS) and exert TS like effect. The total effect such gene expression exerts is responsible for the rare occurrence and benign nature of primary cardiac tumors. This prevents the progression of tumorigenesis. But this also limits the regenerative and proliferative potential of cardiomyocytes. Cardiac Myxoma develops as a consequence of dysregulations in these key genes which revert the cells towards progenitor-like state, hallmark of CM. The CM development in carney complex also signifies the role of TS in cardiac cells.
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Affiliation(s)
- Ovais Shafi
- Sindh Medical College - Jinnah Sindh Medical University / Dow University of Health Sciences, Karachi, Pakistan.
| | - Ghazia Siddiqui
- Sindh Medical College - Jinnah Sindh Medical University / Dow University of Health Sciences, Karachi, Pakistan
| | - Hassam A Jaffry
- Sindh Medical College - Jinnah Sindh Medical University / Dow University of Health Sciences, Karachi, Pakistan
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3
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Daly SM, Peraza A, Newfeld SJ. Computational analysis of prodomain cysteines in human TGF-β proteins reveals frequent loss of disulfide-dependent regulation in tumors. G3 (BETHESDA, MD.) 2022; 12:jkac271. [PMID: 36214621 PMCID: PMC9713452 DOI: 10.1093/g3journal/jkac271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/29/2022] [Indexed: 03/23/2024]
Abstract
The functionally diverse members of the human Transforming Growth Factor-β (TGF-β) family are tightly regulated. TGF-β regulation includes 2 disulfide-dependent mechanisms-dimerization and partner protein binding. The specific cysteines participating in these regulatory mechanisms are known in just 3 of the 33 human TGF-β proteins. Human prodomain alignments revealed that 24 TGF-β prodomains contain conserved cysteines in 2 highly exposed locations. There are 3 in the region of the β8 helix that mediates dimerization near the prodomain carboxy terminus. There are 2 in the Association region that mediates partner protein binding near the prodomain amino terminus. The alignments predict the specific cysteines contributing to disulfide-dependent regulation of 72% of human TGF-β proteins. Database mining then identified 9 conserved prodomain cysteine mutations and their disease phenotypes in 7 TGF-β proteins. Three common adenoma phenotypes for prodomain cysteine mutations suggested 7 new regulatory heterodimer pairs. Two common adenoma phenotypes for prodomain and binding partner cysteine mutations revealed 17 new regulatory interactions. Overall, the analysis of human TGF-β prodomains suggests a significantly expanded scope of disulfide-dependent regulation by heterodimerization and partner protein binding; regulation that is often lost in tumors.
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Affiliation(s)
- Samantha M Daly
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Ashley Peraza
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Stuart J Newfeld
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
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4
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Azab B, Aburizeg D, Ji W, Jeffries L, Isbeih NJ, Al-Akily AS, Mohammad H, Osba YA, Shahin MA, Dardas Z, Hatmal MM, Al-Ammouri I, Lakhani S. TBX5 variant with the novel phenotype of mixed‑type total anomalous pulmonary venous return in Holt‑Oram Syndrome and variable intrafamilial heart defects. Mol Med Rep 2022; 25:210. [PMID: 35514310 PMCID: PMC9133962 DOI: 10.3892/mmr.2022.12726] [Citation(s) in RCA: 2] [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: 01/27/2022] [Accepted: 04/07/2022] [Indexed: 12/04/2022] Open
Abstract
Variants in T‑box transcription factor 5 (TBX5) can result in a wide phenotypic spectrum, specifically in the heart and the limbs. TBX5 has been implicated in causing non‑syndromic cardiac defects and Holt‑Oram syndrome (HOS). The present study investigated the underlying molecular etiology of a family with heterogeneous heart defects. The proband had mixed‑type total anomalous pulmonary venous return (mixed‑type TAPVR), whereas her mother had an atrial septal defect. Genetic testing through trio‑based whole‑exome sequencing was used to reveal the molecular etiology. A nonsense variant was identified in TBX5 (c.577G>T; p.Gly193*) initially showing co‑segregation with a presumably non‑syndromic presentation of congenital heart disease. Subsequent genetic investigations and more complete phenotyping led to the correct diagnosis of HOS, documenting the novel association of mixed‑type TAPVR with HOS. Finally, protein modeling of the mutant TBX5 protein that harbored this pathogenic nonsense variant (p.Gly193*) revealed a substantial drop in the quantity of non‑covalent bonds. The decrease in the number of non‑covalent bonds suggested that the resultant mutant dimer was less stable compared with the wild‑type protein, consequently affecting the protein's ability to bind DNA. The present findings extended the phenotypic cardiac defects associated with HOS; to the best of our knowledge, this is the first association of mixed‑type TAPVR with TBX5. Prior to the current analysis, the molecular association of TAPVR with HOS had never been documented; hence, this is the first genetic investigation to report the association between TAPVR and HOS. Furthermore, it was demonstrated that the null‑variants reported in the T‑box domain of TBX5 were associated with a wide range of cardiac and/or skeletal anomalies on both the inter‑and intrafamilial levels. In conclusion, genetic testing was highlighted as a potentially powerful approach in the prognostication of the proper diagnosis.
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Affiliation(s)
- Bilal Azab
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
- Correspondence to: Dr Bilal Azab, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, 3959 Broadway, New York, NY 10032, USA, E-mail:
| | - Dunia Aburizeg
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Weizhen Ji
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06504, USA
| | - Lauren Jeffries
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06504, USA
| | - Nooredeen Jamal Isbeih
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Amal Saleh Al-Akily
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Hashim Mohammad
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Yousef Abu Osba
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Mohammad A. Shahin
- Department of Pathology and Microbiology and Forensic Medicine, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Zain Dardas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ma'mon M. Hatmal
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa 13133, Jordan
| | - Iyad Al-Ammouri
- Department of Pediatrics, School of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Saquib Lakhani
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06504, USA
- Dr Saquib Lakhani, Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, 1 Park Street, Wing West Pavilion, New Haven, CT 06504, USA, E-mail:
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5
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Wang D, Dong X, Xiong Y, Li Z, Xie Y, Liang S, Huang T. Identification of a novel TBX5 c.755 + 1 G > A variant and related pathogenesis in a family with Holt-Oram syndrome. Am J Med Genet A 2022; 188:58-70. [PMID: 34490705 PMCID: PMC9290998 DOI: 10.1002/ajmg.a.62488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/03/2021] [Accepted: 08/18/2021] [Indexed: 02/05/2023]
Abstract
The proband with congenital heart disease and abnormal thumb was clinically diagnosed as Holt-Oram syndrome (HOS). A novel variant, T-box transcription factor 5 (TBX5) c.755 + 1 G > A, was identified in the proband via whole exome sequencing and validated using Sanger sequencing. Pedigree analysis and clinical examinations revealed three/seven individuals over three generations within the family, with features suggestive of HOS. Deep amplicon sequencing confirmed that the allele frequencies of the novel variant in the proband (III-1), her brother (III-2), and her mother (II-2) were 50%, 48.3%, and 38.1%, respectively, indicating that III-1 and III-2 harbored heterozygous variants, while II-2 harbored mosaic heterozygous variants. The minigene splicing assay showed that the novel variant affected the normal splicing of exon 7, resulting in the production of abnormal TBX5 transcripts. Reverse transcription-quantitative polymerase chain reaction and western blot analyses revealed that the novel variant upregulated TBX5 expression at the transcriptional and translational levels. Nuclear localization assay demonstrated impaired nuclear localization of the mutant TBX5. Cell viability assay revealed the inhibition of cell activity by the mutant TBX5. Our findings indicate that the novel variant was potentially induced HOS, probably by causing aberrant splicing, reducing the enrichment of nuclear TBX5 protein, and inhibiting cellular proliferation.
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Affiliation(s)
- De‐Gang Wang
- Research Center for Reproductive Medicine, Shantou University Medical College, Shantou, China
- Prenatal Diagnosis Center, Boai Hospital of Zhongshan, Zhongshan, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Xing‐Sheng Dong
- Prenatal Diagnosis CenterBoai Hospital of ZhongshanZhongshanChina
| | - Yi Xiong
- Prenatal Diagnosis CenterBoai Hospital of ZhongshanZhongshanChina
- The Second School of Clinical Medicine, Southern Medical UniversityGuangzhouChina
| | - Zhi‐Ming Li
- Prenatal Diagnosis CenterBoai Hospital of ZhongshanZhongshanChina
| | - Ying‐Jun Xie
- Department of Obstetrics and Gynecology, Key Laboratory for Major Obstetric Diseases of Guangdong ProvinceThe Third Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina
| | - Shu‐Hua Liang
- The Second School of Clinical Medicine, Southern Medical UniversityGuangzhouChina
| | - Tian‐Hua Huang
- Research Center for Reproductive Medicine, Shantou University Medical College, Shantou, China
- Chengdu Jinxin Research Institute for Reproductive Medicine and Genetics, Chengdu, China
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6
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Mahfuz AMUB, Khan MA, Deb P, Ansary SJ, Jahan R. Identification of deleterious single nucleotide polymorphism (SNP)s in the human TBX5 gene & prediction of their structural & functional consequences: An in silico approach. Biochem Biophys Rep 2021; 28:101179. [PMID: 34917776 PMCID: PMC8646135 DOI: 10.1016/j.bbrep.2021.101179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 12/29/2022] Open
Abstract
T-box transcription factor 5 gene (TBX5) encodes the transcription factor TBX5, which plays a crucial role in the development of heart and upper limbs. Damaging single nucleotide variants in this gene alter the protein structure, disturb the functions of TBX5, and ultimately cause Holt-Oram Syndrome (HOS). By analyzing the available single nucleotide polymorphism information in the dbSNP database, this study was designed to identify the most deleterious TBX5 SNPs through insilico approaches and predict their structural and functional consequences. Fifty-eight missense substitutions were found damaging by sequence homology-based tools: SIFT and PROVEAN, and structure homology-based tool PolyPhen-2. Various disease association meta-predictors further scrutinized these SNPs. Additionally, conservation profile of the amino acid residues, their surface accessibility, stability, and structural integrity of the native protein upon mutations were assessed. From these analyses, finally 5 SNPs were detected as the most damaging ones: [rs1565941579 (P85S), rs1269970792 (W121R), rs772248871 (V153D), rs769113870 (E208D), and rs1318021626 (I222N)]. Analyses of stop-lost, nonsense, UTR, and splice site SNPs were also conducted. Through integrative bioinformatics analyses, this study has identified the SNPs that are deleterious to the TBX5 protein structure and have the potential to cause HOS. Further wet-lab experiments can validate these findings. Deleterious SNPs in the human TBX5 gene responsible for Holt-Oram Syndrome have been identified. 58 missense and 2 nonsense SNPs were identified as deleterious. 86 3′ UTR SNPs were predicted to be located on miRNA target sites. Possible effects of missense SNPs on the TBX5 protein structure have been studied.
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Affiliation(s)
- A M U B Mahfuz
- Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, 1209, Bangladesh
| | - Md Arif Khan
- Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, 1209, Bangladesh
| | - Promita Deb
- Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, 1209, Bangladesh
| | - Sharmin Jahan Ansary
- Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, 1209, Bangladesh
| | - Rownak Jahan
- Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, 1209, Bangladesh
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7
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Rathjens FS, Blenkle A, Iyer LM, Renger A, Syeda F, Noack C, Jungmann A, Dewenter M, Toischer K, El-Armouche A, Müller OJ, Fabritz L, Zimmermann WH, Zelarayan LC, Zafeiriou MP. Preclinical evidence for the therapeutic value of TBX5 normalization in arrhythmia control. Cardiovasc Res 2021; 117:1908-1922. [PMID: 32777030 PMCID: PMC8262635 DOI: 10.1093/cvr/cvaa239] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 06/26/2020] [Accepted: 07/29/2020] [Indexed: 11/12/2022] Open
Abstract
AIMS Arrhythmias and sudden cardiac death (SCD) occur commonly in patients with heart failure. We found T-box 5 (TBX5) dysregulated in ventricular myocardium from heart failure patients and thus we hypothesized that TBX5 reduction contributes to arrhythmia development in these patients. To understand the underlying mechanisms, we aimed to reveal the ventricular TBX5-dependent transcriptional network and further test the therapeutic potential of TBX5 level normalization in mice with documented arrhythmias. METHODS AND RESULTS We used a mouse model of TBX5 conditional deletion in ventricular cardiomyocytes. Ventricular (v) TBX5 loss in mice resulted in mild cardiac dysfunction and arrhythmias and was associated with a high mortality rate (60%) due to SCD. Upon angiotensin stimulation, vTbx5KO mice showed exacerbated cardiac remodelling and dysfunction suggesting a cardioprotective role of TBX5. RNA-sequencing of a ventricular-specific TBX5KO mouse and TBX5 chromatin immunoprecipitation was used to dissect TBX5 transcriptional network in cardiac ventricular tissue. Overall, we identified 47 transcripts expressed under the control of TBX5, which may have contributed to the fatal arrhythmias in vTbx5KO mice. These included transcripts encoding for proteins implicated in cardiac conduction and contraction (Gja1, Kcnj5, Kcng2, Cacna1g, Chrm2), in cytoskeleton organization (Fstl4, Pdlim4, Emilin2, Cmya5), and cardiac protection upon stress (Fhl2, Gpr22, Fgf16). Interestingly, after TBX5 loss and arrhythmia development in vTbx5KO mice, TBX5 protein-level normalization by systemic adeno-associated-virus (AAV) 9 application, re-established TBX5-dependent transcriptome. Consequently, cardiac dysfunction was ameliorated and the propensity of arrhythmia occurrence was reduced. CONCLUSIONS This study uncovers a novel cardioprotective role of TBX5 in the adult heart and provides preclinical evidence for the therapeutic value of TBX5 protein normalization in the control of arrhythmia.
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MESH Headings
- Animals
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/physiopathology
- Arrhythmias, Cardiac/prevention & control
- Chromatin Immunoprecipitation Sequencing
- Death, Sudden, Cardiac/etiology
- Death, Sudden, Cardiac/prevention & control
- Disease Models, Animal
- Gene Expression Profiling
- Genetic Therapy
- Heart Rate
- Heart Ventricles/metabolism
- Heart Ventricles/physiopathology
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Left Ventricular/therapy
- Isolated Heart Preparation
- Mice, Inbred C57BL
- Mice, Knockout
- RNA-Seq
- T-Box Domain Proteins/genetics
- T-Box Domain Proteins/metabolism
- Transcription, Genetic
- Transcriptome
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Left/therapy
- Ventricular Function, Left
- Ventricular Remodeling
- Mice
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Affiliation(s)
- Franziska S Rathjens
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
- DZHK (German Center for Cardiovascular Disease), partner site, Goettingen, Germany
| | - Alica Blenkle
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
| | - Lavanya M Iyer
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
- DZHK (German Center for Cardiovascular Disease), partner site, Goettingen, Germany
| | - Anke Renger
- Institut für Erziehungswissenschaften, Humboldt University, Berlin, Germany
| | - Fahima Syeda
- Institute of Cardiovascular Science, University of Birmingham, Birmingham, UK
| | - Claudia Noack
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
- DZHK (German Center for Cardiovascular Disease), partner site, Goettingen, Germany
| | - Andreas Jungmann
- Internal Medicine III, University Hospital Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Disease), partner site Heidelberg/Mannheim, Germany
| | - Matthias Dewenter
- DZHK (German Center for Cardiovascular Disease), partner site Heidelberg/Mannheim, Germany
- Department of Molecular Cardiology and Epigenetics, University of Heidelberg, Germany
| | - Karl Toischer
- Department of Cardiology and Pneumology, University Medical Center, Goettingen, Germany
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Technology-Dresden, Germany
| | - Oliver J Müller
- Department of Internal Medicine III, University of Kiel, Kiel, Germany
| | - Larissa Fabritz
- Institute of Cardiovascular Science, University of Birmingham, Birmingham, UK
- Division of Rhythmology, Department of Cardiovascular Medicine, Hospital of the University of Münster, Münster, Germany
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Wolfram-Hubertus Zimmermann
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
- DZHK (German Center for Cardiovascular Disease), partner site, Goettingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Goettingen, Germany
| | - Laura C Zelarayan
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
- DZHK (German Center for Cardiovascular Disease), partner site, Goettingen, Germany
| | - Maria-Patapia Zafeiriou
- Institute of Pharmacology and Toxicology, University Medical Center, Goettingen, Germany
- DZHK (German Center for Cardiovascular Disease), partner site, Goettingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Goettingen, Germany
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8
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Functional analysis of two novel TBX5 variants present in individuals with Holt-Oram syndrome with different clinical manifestations. Mol Genet Genomics 2021; 296:809-821. [PMID: 33866394 DOI: 10.1007/s00438-021-01781-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 03/29/2021] [Indexed: 02/07/2023]
Abstract
Holt-Oram syndrome (HOS) is a rare disorder characterized by cardiac and upper-limb defects. Pathogenic variants in TBX5-a gene encoding a transcription factor important for heart and skeletal development-are the only known cause of HOS. Here, we present the identification and functional analysis of two novel TBX5 pathogenic variants found in two individuals with HOS presenting distinct phenotypes. The individual with the c.905delA variant has a severe cardiac phenotype but mild skeletal defects, unlike the individual with the c.246_249delGATG variant who has no cardiac problems but severe upper limbs malformations, including phocomelia. Both frameshift variants, c.246_249delGATG and c.905delA, generate mRNAs harbouring premature stop codons which, if not degraded by nonsense mediated decay, will lead to the production of shorter TBX5 proteins, p.Gln302Argfs*92 and p.Met83Phefs*6, respectively. Immunocytochemistry results suggest that both mutated proteins are produced and furthermore, like the wild-type protein, p.Gln302Argfs*92 mutant appears to be mainly localized in the nucleus, in contrast with p.Met83Phefs*6 mutant that displays a higher level of cytoplasmic localization. In addition, luciferase activity analysis revealed that none of the TBX5 mutants are capable of transactivating the NPPA promoter. In conclusion, our results provide evidence that both pathogenic variants cause a severe TBX5 loss-of-function, dramatically reducing its biological activity. The absence of cardiac problems in the individual with the p.Met83Phefs*6 variant supports the existence of other mechanisms/genes underlying the pathogenesis of HOS and/or the existence of an age-related delay in the development of a more serious cardiac phenotype. Further studies are required to understand the differential effects observed in the phenotypes of both individuals.
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9
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Taverne YJHJ, Sadeghi A, Bartelds B, Bogers AJJC, Merkus D. Right ventricular phenotype, function, and failure: a journey from evolution to clinics. Heart Fail Rev 2020; 26:1447-1466. [PMID: 32556672 PMCID: PMC8510935 DOI: 10.1007/s10741-020-09982-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The right ventricle has long been perceived as the "low pressure bystander" of the left ventricle. Although the structure consists of, at first glance, the same cardiomyocytes as the left ventricle, it is in fact derived from a different set of precursor cells and has a complex three-dimensional anatomy and a very distinct contraction pattern. Mechanisms of right ventricular failure, its detection and follow-up, and more specific different responses to pressure versus volume overload are still incompletely understood. In order to fully comprehend right ventricular form and function, evolutionary biological entities that have led to the specifics of right ventricular physiology and morphology need to be addressed. Processes responsible for cardiac formation are based on very ancient cardiac lineages and within the first few weeks of fetal life, the human heart seems to repeat cardiac evolution. Furthermore, it appears that most cardiogenic signal pathways (if not all) act in combination with tissue-specific transcriptional cofactors to exert inductive responses reflecting an important expansion of ancestral regulatory genes throughout evolution and eventually cardiac complexity. Such molecular entities result in specific biomechanics of the RV that differs from that of the left ventricle. It is clear that sole descriptions of right ventricular contraction patterns (and LV contraction patterns for that matter) are futile and need to be addressed into a bigger multilayer three-dimensional picture. Therefore, we aim to present a complete picture from evolution, formation, and clinical presentation of right ventricular (mal)adaptation and failure on a molecular, cellular, biomechanical, and (patho)anatomical basis.
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Affiliation(s)
- Yannick J H J Taverne
- Department of Cardiothoracic Surgery, Erasmus University Medical Center, Room Rg627, Dr. Molewaterplein 40, 3015, GD, Rotterdam, The Netherlands. .,Division of Experimental Cardiology, Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands. .,Unit for Cardiac Morphology and Translational Electrophysiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
| | - Amir Sadeghi
- Department of Cardiothoracic Surgery, Erasmus University Medical Center, Room Rg627, Dr. Molewaterplein 40, 3015, GD, Rotterdam, The Netherlands
| | - Beatrijs Bartelds
- Division of Pediatrics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Ad J J C Bogers
- Department of Cardiothoracic Surgery, Erasmus University Medical Center, Room Rg627, Dr. Molewaterplein 40, 3015, GD, Rotterdam, The Netherlands
| | - Daphne Merkus
- Division of Experimental Cardiology, Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands
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10
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Patterson J, Coats C, McGowan R. Familial dilated cardiomyopathy associated with pathogenic TBX5 variants: Expanding the cardiac phenotype associated with Holt-Oram syndrome. Am J Med Genet A 2020; 182:1725-1734. [PMID: 32449309 DOI: 10.1002/ajmg.a.61635] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/03/2020] [Accepted: 04/29/2020] [Indexed: 11/07/2022]
Abstract
Holt-Oram syndrome (HOS) is a rare, autosomal dominant disorder caused by heterozygous pathogenic variants in cardiac T-box transcription factor, TBX5. Classically, it is associated with upper limb malformations and variable cardiac abnormalities. Limb manifestations are considered to be invariably present, ranging in severity from limitation in movement, to triphalangeal thumbs, absent thumbs, shortened forearms, or phocomelia. Cardiac involvement is characterized by congenital heart defects, most commonly septal structural malformations, and conduction system disease. Recently, novel TBX5 variants have also been reported in association with dilated cardiomyopathy (DCM). In this context, we report eight individuals from four unrelated families, in whom pathogenic variants in TBX5 segregated with an atypical HOS phenotype. Affected individuals exhibit relatively mild skeletal features of HOS, with a predominant cardiac phenotype, which includes several individuals affected by non-ischaemic DCM. To our knowledge, these represent the first reported cases of DCM in families with skeletal features of HOS, some of whom also harbored variants previously linked to a classical HOS phenotype (p. Arg279* and p.Arg237Gln). This finding supports diverse roles of TBX5 in cardiovascular development and function, and confirms the importance of long-term cardiac surveillance for individuals affected by HOS. Furthermore, these families highlight the wide phenotypic variability of HOS, which may include comparatively mild upper limb findings in respect to cardiac manifestations.
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Affiliation(s)
- Jenny Patterson
- West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, UK
| | - Caroline Coats
- Department of Cardiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Ruth McGowan
- West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, UK
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11
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Holt-Oram syndrome: clinical and molecular description of 78 patients with TBX5 variants. Eur J Hum Genet 2018; 27:360-368. [PMID: 30552424 DOI: 10.1038/s41431-018-0303-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 10/12/2018] [Accepted: 10/25/2018] [Indexed: 12/24/2022] Open
Abstract
Holt-Oram syndrome (HOS) is an autosomal dominant condition characterised by the association of congenital heart defect (CHD), with or without rhythm disturbances and radial defects, due to TBX5 variants. The diagnosis is challenged by the variability of expression and the large phenotypic overlap with other conditions, like Okihiro syndrome, TAR syndrome or Fanconi disease. We retrospectively reviewed 212 patients referred for suspicion of HOS between 2002 and 2014, who underwent TBX5 screening. A TBX5 variant has been identified in 78 patients, representing the largest molecular series ever described. In the cohort, 61 met the previously described diagnostic criteria and 17 have been considered with an uncertain HOS diagnosis. A CHD was present in 91% of the patients with a TBX5 variant, atrial septal defects being the most common (61.5%). The genotype-phenotype study highlights the importance of some critical features in HOS: the septal characteristic of the CHD, the bilateral and asymmetric characteristics of the radial defect and the presence of shoulder or elbow mobility defect. Besides, 21 patients presented with an overlapping condition. Among them, 13 had a typical HOS presentation. We discuss the strategies that could be adopted to improve the molecular delineation of the remaining typical patients.
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12
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Tsai TC, Shih CC, Chien HP, Yang AH, Lu JK, Lu JH. Anti-apoptotic effects of IGF-I on mortality and dysmorphogenesis in tbx5-deficient zebrafish embryos. BMC DEVELOPMENTAL BIOLOGY 2018; 18:5. [PMID: 29506474 PMCID: PMC5836385 DOI: 10.1186/s12861-017-0161-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/05/2017] [Indexed: 01/21/2023]
Abstract
BACKGROUND Tbx5 deficiency in zebrafish causes several abnormal phenotypes of the heart and pectoral fins. It has been reported that exogenous human growth hormone can enhance expression of downstream mediators in the growth hormone and insulin-like growth factor I (IGF-I) pathway and partially restore dysmorphogenesis in tbx5 morphants. This study aimed to further evaluate the effects of IGF-I on cell apoptosis and dysmorphogenesis in zebrafish embryos deficient for tbx5. RESULTS Among the five studied groups of zebrafish embryos (wild-type embryos [WT], tbx5 morphants [MO], mismatched tbx5 morpholino-treated wild-type embryos [MIS], IGF-I-treated wild-type embryos [WTIGF1], and IGF-I-treated tbx5 morphants [MOIGF1]), the expression levels of the ifg1, igf1-ra, ifg-rb, erk1, and akt2 genes as well as the ERK and AKT proteins were significantly reduced in the MO group, but were partially restored in the MOIGF1 group. These expression levels remained normal in the WT, MIS, and WTIGF1 groups. Exogenous human IGF-I also reduced the incidence of phenotypic anomalies, decreased the expression levels of apoptotic genes and proteins, suppressed cell apoptosis, and improved survival of the MOIGF1 group. CONCLUSIONS These results suggest that IGF-I has an anti-apoptotic protective effect in zebrafish embryos with tbx5 deficiency.
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Affiliation(s)
- Tzu-Chun Tsai
- Institutes of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Chun-Che Shih
- Institutes of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Departments of Surgery, Pediatrics and Pathology, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China
| | - Hsin-Ping Chien
- Laboratory of Molecular Biology, Institute of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan, Republic of China
| | - An-Hang Yang
- Institutes of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Departments of Surgery, Pediatrics and Pathology, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China
| | - Jenn-Kan Lu
- Laboratory of Molecular Biology, Institute of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan, Republic of China. .,Department of Pediatrics, Veterans General Hospital-Taipei, No. 201, Shih-Pei Rd., Section 2, Beitou, Taipei, 112, Taiwan, Republic of China.
| | - Jen-Her Lu
- Institutes of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China. .,Departments of Surgery, Pediatrics and Pathology, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China. .,Department of Pediatrics, Veterans General Hospital-Taipei, No. 201, Shih-Pei Rd., Section 2, Beitou, Taipei, 112, Taiwan, Republic of China.
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13
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Ross SB, Bagnall RD, Yeates L, Sy RW, Semsarian C. Holt-Oram syndrome in two families diagnosed with left ventricular noncompaction and conduction disease. HeartRhythm Case Rep 2018; 4:146-151. [PMID: 29755943 PMCID: PMC5944048 DOI: 10.1016/j.hrcr.2017.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Samantha Barratt Ross
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
| | - Richard D Bagnall
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
| | - Laura Yeates
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Raymond W Sy
- Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
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14
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Wang F, Liu D, Zhang RR, Yu LW, Zhao JY, Yang XY, Jiang SS, Ma D, Qiao B, Zhang F, Jin L, Gui YH, Wang HY. A TBX5 3'UTR variant increases the risk of congenital heart disease in the Han Chinese population. Cell Discov 2017; 3:17026. [PMID: 28761722 PMCID: PMC5527299 DOI: 10.1038/celldisc.2017.26] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/29/2017] [Indexed: 12/27/2022] Open
Abstract
TBX5 is a vital transcription factor involved in cardiac development in a dosage-dependent manner. But little is known about the potential association of TBX5 3′ untranslated region (UTR) variations with congenital cardiac malformations. This study aimed to investigate the relationship between TBX5 3′UTR variants and risk for congenital heart disease (CHD) susceptibility in two Han Chinese populations, and to reveal its molecular mechanism. The relationship between TBX5 3′UTR variants and CHD susceptibility was examined in 1 177 CHD patients and 990 healthy controls in two independent case–control studies. Variant rs6489956 C>T was found to be associated with increased CHD susceptibility in both cohorts. The combined CHD risk for the CT and TT genotype carriers was 1.83 times higher than that of CC genotype, while the risk for CT or TT genotype was 1.94 times and 2.31 times higher than that of CC carriers, respectively. Quantitative real-time PCR and western blot analysis showed that T allele carriers exhibited reduced TBX5 mRNA and protein levels in CHDs tissues. Compared with C allele, T allele showed increased binding affinity to miR-9 and miR-30a in both luciferase assays and surface plasmon resonance analysis. Functional analysis confirmed that miR-9 and miR-30a downregulated TBX5 expression at the transcriptional and translational levels, respectively. The assays in zebrafish model were in support of the interaction of miR-9/30a and TBX5 3′UTR (C and T allele). We concluded that TBX5 3′UTR variant rs6489956 increased susceptibility of CHD in the Han Chinese population because it changes the binding affinity of two target miRNAs that specifically mediate TBX5 expression.
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Affiliation(s)
- Feng Wang
- Children's Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction & Development, Fudan University, Shanghai, China
| | - Dong Liu
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong University, Nantong, China
| | - Ran-Ran Zhang
- Children's Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction & Development, Fudan University, Shanghai, China
| | - Li-Wei Yu
- Children's Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction & Development, Fudan University, Shanghai, China
| | - Jian-Yuan Zhao
- The State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Xue-Yan Yang
- The State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Song-Shan Jiang
- The State Key laboratory for Biocontrol and MOE Key Laboratory of Gene Engineering, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Duan Ma
- Key Laboratory of Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Institute of Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Bin Qiao
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, Jinan, China
| | - Feng Zhang
- The Obstetrics & Gynecology Hospital, Key Laboratory of Reproduction Regulation of NPFPC, Institute of Reproduction & Development, Fudan University, Shanghai, China
| | - Li Jin
- The State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Yong-Hao Gui
- Children's Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction & Development, Fudan University, Shanghai, China
| | - Hong-Yan Wang
- The Obstetrics & Gynecology Hospital, Key Laboratory of Reproduction Regulation of NPFPC, Institute of Reproduction & Development, Fudan University, Shanghai, China
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15
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Tbx5 Buffers Inherent Left/Right Asymmetry Ensuring Symmetric Forelimb Formation. PLoS Genet 2016; 12:e1006521. [PMID: 27992425 PMCID: PMC5215935 DOI: 10.1371/journal.pgen.1006521] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/05/2017] [Accepted: 12/02/2016] [Indexed: 11/19/2022] Open
Abstract
The forelimbs and hindlimbs of vertebrates are bilaterally symmetric. The mechanisms that ensure symmetric limb formation are unknown but they can be disrupted in disease. In Holt-Oram Syndrome (HOS), caused by mutations in TBX5, affected individuals have left-biased upper/forelimb defects. We demonstrate a role for the transcription factor Tbx5 in ensuring the symmetric formation of the left and right forelimb. In our mouse model, bilateral hypomorphic levels of Tbx5 produces asymmetric forelimb defects that are consistently more severe in the left limb than the right, phenocopying the left-biased limb defects seen in HOS patients. In Tbx hypomorphic mutants maintained on an INV mutant background, with situs inversus, the laterality of defects is reversed. Our data demonstrate an early, inherent asymmetry in the left and right limb-forming regions and that threshold levels of Tbx5 are required to overcome this asymmetry to ensure symmetric forelimb formation. Externally, the human form appears bilaterally symmetric. For example, each of our pairs of arms and legs are the same length. This external symmetry masks many asymmetries found in internal organs. In most people the heart is found on the left side of the chest. The stomach, liver and spleen are also positioned asymmetrically. The authors of this study demonstrate, using a mouse model, that bilateral symmetry of the arms is not a default, passive state but that mechanisms are in place that ensure symmetrical formation of the left and right limbs. Bilateral symmetry of the arms is achieved by the action of a gene Tbx5 that masks the effects of signals that acted earlier during embryogenesis, many days before limb formation, and imposed asymmetries on the forming internal organs. Maintaining bilateral symmetry of the arms is important for them to carry out their normal functions but this process can go wrong. Holt-Oram syndrome patients have upper limb defects, including shortened arms. Consistently the defects are more severe in their left arm than right. This birth defect is caused by disruption of the TBX5 gene. By linking the action of Tbx5 to symmetrical limb formation, the authors provide an explanation for why Holt-Oram syndrome patients have more severe defects in the left arms than right.
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16
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Eckhardt LL, Makielski JC. Complexity of AF genetic susceptibility begets complexity of interpretation. Heart Rhythm 2016; 14:292-293. [PMID: 27825974 DOI: 10.1016/j.hrthm.2016.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Indexed: 11/19/2022]
Affiliation(s)
- Lee L Eckhardt
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Jonathan C Makielski
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
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17
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Abstract
TBX5 is a member of the T-box transcription factor family and is primarily known for its role in cardiac and forelimb development. Human patients with dominant mutations in TBX5 are characterized by Holt-Oram syndrome, and show defects of the cardiac septa, cardiac conduction system, and the anterior forelimb. The range of cardiac defects associated with TBX5 mutations in humans suggests multiple roles for the transcription factor in cardiac development and function. Animal models demonstrate similar defects and have provided a useful platform for investigating the roles of TBX5 during embryonic development. During early cardiac development, TBX5 appears to act primarily as a transcriptional activator of genes associated with cardiomyocyte maturation and upstream of morphological signals for septation. During later cardiac development, TBX5 is required for patterning of the cardiac conduction system and maintenance of mature cardiomyocyte function. A comprehensive understanding of the integral roles of TBX5 throughout cardiac development and adult life will be critical for understanding human cardiac morphology and function.
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Affiliation(s)
- J D Steimle
- University of Chicago, Chicago, IL, United States
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18
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Dreßen M, Lahm H, Lahm A, Wolf K, Doppler S, Deutsch MA, Cleuziou J, Pabst von Ohain J, Schön P, Ewert P, Malcic I, Lange R, Krane M. A novel de novo TBX5 mutation in a patient with Holt-Oram syndrome leading to a dramatically reduced biological function. Mol Genet Genomic Med 2016; 4:557-67. [PMID: 27652283 PMCID: PMC5023941 DOI: 10.1002/mgg3.234] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 01/26/2023] Open
Abstract
Background The Holt–Oram syndrome (HOS) is an autosomal dominant disorder affecting 1/100.000 live births. It is defined by upper limb anomalies and congenital heart defects with variable severity. We describe a dramatic phenotype of a male, 15‐month‐old patient being investigated for strict diagnostic criteria of HOS. Methods and results Genetic analysis revealed a so far unpublished TBX5 mutation, which occurs de novo in the patient with healthy parents. TBX5 belongs to the large family of T‐box transcription factors playing major roles in morphogenesis and cell‐type specification. The mutation located in the DNA‐binding domain at position 920 (C→A) leads to an amino acid change at position 85 (proline → threonine). Three‐dimensional analysis of the protein structure predicted a cis to trans change in the respective peptide bond, thereby probably provoking major conformational and functional alterations of the protein. The p.Pro85Thr mutation showed a dramatically reduced activation (97%) of the NPPA promoter in luciferase assays and failed to induce NPPA expression in HEK 293 cells compared to wild‐type TBX5 protein. The mutation did not interfere with the nuclear localization of the protein. Conclusion These results suggest that the dramatic functional alteration of the p.Pro85Thr mutation leads to the distinctive phenotype of the patient.
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Affiliation(s)
- Martina Dreßen
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Harald Lahm
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Armin Lahm
- Bioinformatics Project Support Rome Italy
| | - Klaudia Wolf
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Stefanie Doppler
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Marcus-André Deutsch
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Julie Cleuziou
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Jelena Pabst von Ohain
- Department of Cardiovascular Surgery Division of Experimental Surgery German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Patric Schön
- Department of Paediatric Cardiology and Congenital Heart Defects German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Peter Ewert
- Department of Paediatric Cardiology and Congenital Heart Defects German Heart Center Munich at the Technical University of Munich Munich Germany
| | - Ivan Malcic
- Department of Pediatrics Division of Cardiology and Intensive Care Unit University Hospital Zagreb Zagreb Croatia
| | - Rüdiger Lange
- Department of Cardiovascular SurgeryDivision of Experimental SurgeryGerman Heart Center Munich at the Technical University of MunichMunichGermany; DZHK (German Center for Cardiovascular Research) - partner site Munich Heart AllianceMunichGermany
| | - Markus Krane
- Department of Cardiovascular SurgeryDivision of Experimental SurgeryGerman Heart Center Munich at the Technical University of MunichMunichGermany; DZHK (German Center for Cardiovascular Research) - partner site Munich Heart AllianceMunichGermany
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19
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Yoshida A, Morisaki H, Nakaji M, Kitano M, Kim KS, Sagawa K, Ishikawa S, Satokata I, Mitani Y, Kato H, Hamaoka K, Echigo S, Shiraishi I, Morisaki T. Genetic mutation analysis in Japanese patients with non-syndromic congenital heart disease. J Hum Genet 2015; 61:157-62. [DOI: 10.1038/jhg.2015.126] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/01/2015] [Accepted: 09/23/2015] [Indexed: 12/22/2022]
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20
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Al-Qattan MM, Abou Al-Shaar H. Molecular basis of the clinical features of Holt–Oram syndrome resulting from missense and extended protein mutations of the TBX5 gene as well as TBX5 intragenic duplications. Gene 2015; 560:129-36. [DOI: 10.1016/j.gene.2015.02.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 11/24/2014] [Accepted: 02/02/2015] [Indexed: 01/13/2023]
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21
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Zhou M, Liao Y, Tu X. The role of transcription factors in atrial fibrillation. J Thorac Dis 2015; 7:152-8. [PMID: 25713730 DOI: 10.3978/j.issn.2072-1439.2015.01.21] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 12/09/2014] [Indexed: 12/21/2022]
Abstract
Atrial fibrillation (AF) is a complex disease that results from genetic and environmental factors and their interactions. In recent years, genome-wide association studies (GWAS) and family-based linkage analysis have found amounts of genetic variants associated with AF. Some of them lie in coding sequences and thus mediate the encoded proteins, some in non-coding regions and influence the expression of adjacent genes. These variants exert influence on the development of cardiovascular system and normal cardiac electrical activity in different levels, and eventually contribute to the occurrence of AF. Among these affected genes, as a crucial means of transcriptional regulation, several transcription factors play important roles in the pathogenesis of AF. In this review, we will focus on the potential role of PITX2, PRRX1, ZHFX3, TBX5, and NKX2.5 in AF.
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Affiliation(s)
- Mengchen Zhou
- 1 Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan 430074, China ; 2 Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430000, China
| | - Yuhua Liao
- 1 Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan 430074, China ; 2 Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430000, China
| | - Xin Tu
- 1 Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan 430074, China ; 2 Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430000, China
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22
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Barisic I, Boban L, Greenlees R, Garne E, Wellesley D, Calzolari E, Addor MC, Arriola L, Bergman JE, Braz P, Budd JL, Gatt M, Haeusler M, Khoshnood B, Klungsoyr K, McDonnell B, Nelen V, Pierini A, Queisser-Wahrendorf A, Rankin J, Rissmann A, Rounding C, Tucker D, Verellen-Dumoulin C, Dolk H. Holt Oram syndrome: a registry-based study in Europe. Orphanet J Rare Dis 2014; 9:156. [PMID: 25344219 PMCID: PMC4245183 DOI: 10.1186/s13023-014-0156-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/30/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Holt-Oram syndrome (HOS) is an autosomal dominant disorder characterised by upper limb anomalies and congenital heart defects. We present epidemiological and clinical aspects of HOS patients using data from EUROCAT (European Surveillance of Congenital Anomalies) registries. METHODS The study was based on data collected during 1990-2011 by 34 registries. The registries are population-based and use multiple sources of information to collect data on all types of birth using standardized definitions, methodology and coding. Diagnostic criteria for inclusion in the study were the presence of radial ray abnormalities and congenital heart disease (CHD), or the presence of either radial ray anomaly or CHD, with family history of HOS. RESULTS A total of 73 cases of HOS were identified, including 11 (15.1%) TOPFA and 62 (84.9%) LB. Out of 73 HOS cases, 30.8% (20/65) were suspected prenatally, 55.4% (36/65) at birth, 10.7% (7/65) in the first week of life, and 3.1% (2/65) in the first year of life. The prenatal detection rate was 39.2% (20/51), with no significant change over the study period. In 55% (11/20) of prenatally detected cases, parents decided to terminate pregnancy. Thumb anomalies were reported in all cases. Agenesis/hypoplasia of radius was present in 49.2% (30/61), ulnar aplasia/hypoplasia in 24.6% (15/61) and humerus hypoplasia/phocomelia in 42.6% (26/61) of patients. Congenital heart defects (CHD) were recorded in 78.7% (48/61) of patients. Isolated septal defects were present in 54.2 (26/48), while 25% (12/48) of patients had complex/severe CHD. The mean prevalence of HOS diagnosed prenatally or in the early years of life in European registries was 0.7 per 100,000 births or 1:135,615 births. CONCLUSIONS HOS is a rare genetic condition showing regional variation in its prevalence. It is often missed prenatally, in spite of the existence of major structural anomalies. When discovered, parents in 45% (9/20) of cases opt for the continuation of pregnancy. Although a quarter of patients have severe CHD, the overall first week survival is very good, which is important information for counselling purposes.
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23
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Baban A, Postma AV, Marini M, Trocchio G, Santilli A, Pelegrini M, Sirleto P, Lerone M, Albanese SB, Barnett P, Boogerd CJ, Dallapiccola B, Digilio MC, Ravazzolo R, Pongiglione G. Identification of TBX5 mutations in a series of 94 patients with Tetralogy of Fallot. Am J Med Genet A 2014; 164A:3100-7. [PMID: 25263169 DOI: 10.1002/ajmg.a.36783] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 08/22/2014] [Indexed: 01/02/2023]
Abstract
Tetralogy of Fallot (TOF) (OMIM #187500) is the most frequent conotruncal congenital heart defect (CHD) with a range of intra- and extracardiac phenotypes. TBX5 is a transcription factor with well-defined roles in heart and forelimb development, and mutations in TBX5 are associated with Holt-Oram syndrome (HOS) (OMIM#142900). Here we report on the screening of 94 TOF patients for mutations in TBX5, NKX2.5 and GATA4 genes. We identified two heterozygous mutations in TBX5. One mutation was detected in a Moroccan patient with TOF, a large ostium secundum atrial septal defect and complete atrioventricular block, and features of HOS including bilateral triphalangeal thumbs and fifth finger clinodactyly. This patient carried a previously described de novo, stop codon mutation (p.R279X) located in exon 8 causing a premature truncated protein. In a second patient from Italy with TOF, ostium secundum atrial septal defect and progressive arrhythmic changes on ECG, we identified a maternally inherited novel mutation in exon 9, which caused a substitution of a serine with a leucine at amino acid position 372 (p.S372L, c.1115C>T). The mother's clinical evaluation demonstrated frequent ventricular extrasystoles and an atrial septal aneurysm. Physical examination and radiographs of the hands showed no apparent skeletal defects in either child or mother. Molecular evaluation of the p.S372L mutation demonstrated a gain-of-function phenotype. We also review the literature on the co-occurrence of TOF and HOS, highlighting its relevance. This is the first systematic screening for TBX5 mutations in TOF patients which detected mutations in two of 94 (2.1%) patients.
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Affiliation(s)
- Anwar Baban
- Department of Pediatric Cardiology and Cardiosurgery, Bambino Gesù Children Hospital, IRCCS, Rome, Italy
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Wang F, Yang XY, Zhao JY, Yu LW, Zhang P, Duan WY, Chong M, Gui YH. miR-10a and miR-10b target the 3'-untranslated region of TBX5 to repress its expression. Pediatr Cardiol 2014; 35:1072-9. [PMID: 24714979 DOI: 10.1007/s00246-014-0901-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 03/25/2014] [Indexed: 11/27/2022]
Abstract
As a well-known transcription factor, TBX5 is involved in embryonic cardiac development. Although TBX5 functions in a dose-dependent manner, the posttranscriptional regulation of human TBX5 is poorly understood. Thus, this study aimed to identify microRNAs that modulate TBX5 expression. Luciferase assays were used to screen miRNAs predicted to modulate TBX5 expression. Using quantitative reverse transcriptase-polymerase chain reaction and Western blot analysis, the authors found that miR-10a and miR-10b significantly repressed TBX5 expression and decreased TBX5 protein levels by targeting the TBX5 3'-untranslated region. In addition, miR-10a and miR-10b expression levels were respectively 2.77 and 3.51 times higher in the heart tissues of congenital heart disease patients than in healthy control subjects, suggesting that they are potential diagnostic biomarkers. In conclusion, the study results indicate that miR-10a and miR-10b inhibit TBX5 expression at the level of translation. Higher levels of miR-10a and miR-10b expression are associated with a higher risk of congenital heart defects.
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Affiliation(s)
- Feng Wang
- Department of Cardiology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China
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25
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Beketaev I, Kim EY, Zhang Y, Yu W, Qian L, Wang J. Potentiation of Tbx5-mediated transactivation by SUMO conjugation and protein inhibitor of activated STAT 1 (PIAS1). Int J Biochem Cell Biol 2014; 50:82-92. [DOI: 10.1016/j.biocel.2014.02.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 01/30/2014] [Accepted: 02/11/2014] [Indexed: 12/18/2022]
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26
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Heithaus JL, Davenport S, Twyman KA, Torti EE, Batanian JR. An intragenic deletion of the gene MNAT1 in a family with pectus deformities. Am J Med Genet A 2014; 164A:1293-7. [PMID: 24664931 DOI: 10.1002/ajmg.a.36445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 12/26/2013] [Indexed: 11/07/2022]
Abstract
Pectus carinatum and excavatum have multiple genetic associations. We report on a novel association of these deformities in a 34-month-old male and his father, likely due to a small intragenic deletion of MNAT1 (ménage a trois 1 gene). Both individuals share a deletion of MNAT1 located at 14q23.1 and an interstitial duplication of CHRNA7 located at 15q13.3. Deletion of MNAT1 has been associated with connective tissue abnormalities and is likely the etiology of the malformations, whereas the duplication of CHNRA7 is unlikely related due to the lack of association with any such connective tissue abnormalities.
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Affiliation(s)
- Jennifer L Heithaus
- Department of Pediatrics, Genetics Division, Saint Louis University School of Medicine, St. Louis, Missouri
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27
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Baban A, Pitto L, Pulignani S, Cresci M, Mariani L, Gambacciani C, Digilio MC, Pongiglione G, Albanese S. Holt-Oram syndrome with intermediate atrioventricular canal defect, and aortic coarctation: Functional characterization of a de novoTBX5mutation. Am J Med Genet A 2014; 164A:1419-24. [DOI: 10.1002/ajmg.a.36459] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 12/26/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Anwar Baban
- Department of Pediatric Cardiology and Cardiac Surgery; Bambino Gesù Children's Hospital; IRCCS; Rome Italy
| | | | | | | | | | | | - Maria Cristina Digilio
- Department of Pediatric Cardiology and Cardiac Surgery; Bambino Gesù Children's Hospital; IRCCS; Rome Italy
| | - Giacomo Pongiglione
- Department of Pediatric Cardiology and Cardiac Surgery; Bambino Gesù Children's Hospital; IRCCS; Rome Italy
| | - Sonia Albanese
- Department of Pediatric Cardiology and Cardiac Surgery; Bambino Gesù Children's Hospital; IRCCS; Rome Italy
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28
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Corradi D. Atrial fibrillation from the pathologist's perspective. Cardiovasc Pathol 2013; 23:71-84. [PMID: 24462196 DOI: 10.1016/j.carpath.2013.12.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 12/03/2013] [Accepted: 12/07/2013] [Indexed: 12/18/2022] Open
Abstract
Atrial fibrillation (AF), the most common sustained cardiac arrhythmia encountered in clinical practice, is associated with increased morbidity and mortality. Electrophysiologically, it is characterized by a high rate of asynchronous atrial cell depolarization causing a loss of atrial contractile function and irregular ventricular rates. For a long time, AF was considered as a pure functional disorder without any structural background. Only in recent years, have new mapping and imaging techniques identified atrial locations, which are very often involved in the initiation and maintenance of this supraventricular arrhythmia (i.e. the distal portion of the pulmonary veins and the surrounding atrial myocardium). Morphological analysis of these myocardial sites has demonstrated significant structural remodeling as well as paved the way for further knowledge of AF natural history, pathogenesis, and treatment. This architectural myocardial disarrangement is induced by the arrhythmia itself and the very frequently associated cardiovascular disorders. At the same time, the structural remodeling is also capable of sustaining AF, thereby creating a sort of pathogenetic vicious circle. This review focuses on current understanding about the structural and genetic bases of AF with reference to their classification, pathogenesis, and clinical implications.
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Affiliation(s)
- Domenico Corradi
- Department of Biomedical, Biotechnological, and Translational Sciences (S.Bi.Bi.T.), Unit of Pathology, University of Parma, Parma, Italy.
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29
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Yang YQ, Gharibeh L, Li RG, Xin YF, Wang J, Liu ZM, Qiu XB, Xu YJ, Xu L, Qu XK, Liu X, Fang WY, Huang RT, Xue S, Nemer G. GATA4 loss-of-function mutations underlie familial tetralogy of fallot. Hum Mutat 2013; 34:1662-71. [PMID: 24000169 DOI: 10.1002/humu.22434] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 08/23/2013] [Indexed: 01/01/2023]
Abstract
Tetralogy of Fallot (TOF) represents the most common form of cyanotic congenital heart disease and accounts for significant morbidity and mortality in humans. Emerging evidence has implicated genetic defects in the pathogenesis of TOF. However, TOF is genetically heterogeneous and the genetic basis for TOF in most patients remains unclear. In this study, the GATA4 gene were sequenced in 52 probands with familial TOF, and three novel heterozygous mutations, including A9P and L51V both located in the putative first transactivational domain and N285S in the C-terminal zinc finger, were identified in three probands, respectively. Genetic analysis of the pedigrees demonstrated that in each family the mutation cosegregated with TOF with complete penetrance. The missense mutations were absent in 800 control chromosomes and the altered amino acids were highly conserved evolutionarily. Functional analysis showed that the GATA4 mutants were consistently associated with diminished DNA-binding affinity and decreased transcriptional activity. Furthermore, the N285S mutation completely disrupted the physical interaction between GATA4 and TBX5. To our knowledge, this report associates GATA4 loss-of-function mutations with familial TOF for the first time, providing novel insight into the molecular mechanism involved in TOF and suggesting potential implications for the early prophylaxis and allele-specific therapy of TOF.
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Affiliation(s)
- Yi-Qing Yang
- Department of Cardiology and Cardiovascular Research, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
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30
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Franklin AD, Lorinc AN, Donahue BS. Malignant hyperthermia-like manifestations in a two-month-old child with Holt-Oram syndrome undergoing cardiac surgery. J Cardiothorac Vasc Anesth 2013; 28:1326-7. [PMID: 24011877 DOI: 10.1053/j.jvca.2013.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Andrew D Franklin
- Monroe Carell Jr. Children's Hospital at Vanderbilt, Vanderbilt University School of Medicine, Nashville, TN.
| | - Amanda N Lorinc
- Monroe Carell Jr. Children's Hospital at Vanderbilt, Vanderbilt University School of Medicine, Nashville, TN
| | - Brian S Donahue
- Monroe Carell Jr. Children's Hospital at Vanderbilt, Vanderbilt University School of Medicine, Nashville, TN
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31
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Cheng C, Lin Y, Yang F, Wang W, Wu C, Qin J, Shao X, Zhou L. Mutational screening of affected cardiac tissues and peripheral blood cells identified novel somatic mutations in GATA4 in patients with ventricular septal defect. J Biomed Res 2013; 25:425-30. [PMID: 23554720 PMCID: PMC3596722 DOI: 10.1016/s1674-8301(11)60056-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 07/31/2011] [Accepted: 10/05/2011] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to examine how somatic mutations of the GATA4 gene contributed to the genesis of ventricular septal defect (VSD). The coding and intron-exon boundary regions of GATA4 were sequenced of DNA samples from peripheral blood cells and cardiac tissues of twenty surgically treated probands with VSD. Seven novel heterozygous variants were detected in cardiac tissues from VSD patients, but they were not detected in the peripheral blood cells of VSD patients or in 500 healthy control samples. We replicated 14 single nucleotide polymorphisms (SNPs) reported in NCBI. Bioinformatics analysis was performed to analyze the possible mechanism by which mutations were linked to VSD. Among those variants, c. 1004C>A (p.S335X) occurred in the highly conserved domain of GATA4 and generated a termination codon, which led to the production of truncated GATA4. The seven novel heterozygous GATA4 mutations were only identified in cardiac tissues with VSD, suggesting that they are of somatic origin. A higher mutation rate in cardiac tissues than in peripheral blood cells implies that the genetic contribution to VSD may have been underestimated.
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Affiliation(s)
- Chunyan Cheng
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
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Lu J, Tsai T, Choo S, Yeh S, Tang R, Yang A, Lee H, Lu J. Induction of apoptosis and inhibition of cell growth by tbx5 knockdown contribute to dysmorphogenesis in Zebrafish embryos. J Biomed Sci 2011; 18:73. [PMID: 21982178 PMCID: PMC3199240 DOI: 10.1186/1423-0127-18-73] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Accepted: 10/08/2011] [Indexed: 12/28/2022] Open
Abstract
Background The tbx5 mutation in human causes Holt-Oram syndrome, an autosomal dominant condition characterized by a familial history of congenital heart defects and preaxial radial upper-limb defects. We report aberrant apoptosis and dormant cell growth over head, heart, trunk, fin, and tail of zebrafish embryos with tbx5 deficiency correspond to the dysmorphogenesis of tbx5 morphants. Methods Wild-type zebrafish embryos at the 1-cell stage were injected with 4.3 nl of 19.4 ng of tbx5 morpholino or mismatch-tbx5-MO respectively in tbx5 morphants and mismatched control group. Semi-quantitative RT-PCR was used to for expression analysis of apoptosis and cell cycle-related genes. TUNEL and immunohistochemical assay showed the apoptosis spots within the local tissues. Ultra-structure of cardiac myocardium was examined by transmission electron microscope. Results Apoptosis-related genes (bad, bax, and bcl2), and cell cycle-related genes (cdk2, pcna, p27, and p57) showed remarkable increases in transcriptional level by RT-PCR. Using a TUNEL and immnuohistochemical assay, apoptosis was observed in the organs including the head, heart, pectoral fins, trunk, and tail of tbx5 knockdown embryos. Under transmission electron microscopic examination, mitochondria in cardiomyocytes became swollen and the myocardium was largely disorganized with a disarrayed appearance, compatible with reduced enhancement of myosin in the cardiac wall. The ATP level was reduced, and the ADP/ATP ratio as an apoptotic index significantly increased in the tbx5 deficient embryos. Conclusion Our study highlighted that tbx5 deficiency evoked apoptosis, distributed on multiple organs corresponding to dysmorphogenesis with the shortage of promising maturation, in tbx5 knockdown zebrafish embryos. We hypothesized that mesenchymal cell apoptosis associated with altered TBX5 level may subsequently interfered with organogenesis and contributed to dysmorphogenesis in tbx5 deficiency zebrafish embryos.
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Affiliation(s)
- Jenher Lu
- Department of Pediatrics and Pathology, Taipei Veterans General Hospital, Taipei, Taiwan.
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Abstract
The transcriptional regulation orchestrating the development of the heart is increasingly recognized to play an essential role in the regulation of ion channel and gap junction gene expression and consequently the proper generation and conduction of the cardiac electrical impulse. This has led to the realization that in some instances, abnormal cardiac electrical function and arrhythmias in the postnatal heart may stem from a developmental abnormality causing maintained (epigenetic) changes in gene regulation. The role of developmental genes in the regulation of cardiac electrical function is further underscored by recent genome-wide association studies that provide strong evidence that common genetic variation, at loci harbouring these genes, modulates electrocardiographic indices of conduction and repolarization and susceptibility to arrhythmia. Here we discuss recent findings and provide background insight into these complex mechanisms.
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Affiliation(s)
- Alex V Postma
- Heart Failure Research Center, Academic Medical Center, Amsterdam, The Netherlands
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