1
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Olejnickova V, Hamor PU, Janacek J, Bartos M, Zabrodska E, Sankova B, Kvasilova A, Kolesova H, Sedmera D. Development of ventricular trabeculae affects electrical conduction in the early endothermic heart. Dev Dyn 2024; 253:78-90. [PMID: 36400745 DOI: 10.1002/dvdy.552] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/09/2022] [Accepted: 11/09/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The ventricular trabeculae play a role, among others, in the impulse spreading in ectothermic hearts. Despite the morphological similarity with the early developing hearts of endotherms, this trabecular function in mammalian and avian embryos was poorly addressed. RESULTS We simulated impulse propagation inside the looping ventricle and revealed delayed apical activation in the heart with inhibited trabecular growth. This finding was corroborated by direct imaging of the endocardial surface showing early activation within the trabeculae implying preferential spreading of depolarization along with them. Targeting two crucial pathways of trabecular formation (Neuregulin/ErbB and Nkx2.5), we showed that trabecular development is also essential for proper conduction patterning. Persistence of the slow isotropic conduction likely contributed to the pumping failure in the trabeculae-deficient hearts. CONCLUSIONS Our results showed the essential role of trabeculae in intraventricular impulse spreading and conduction patterning in the early endothermic heart. Lack of trabeculae leads to the failure of conduction parameters differentiation resulting in primitive ventricular activation with consequent impact on the cardiac pumping function.
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Affiliation(s)
- Veronika Olejnickova
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Laboratory of Developmental Cardiology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Uriel Hamor
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jiri Janacek
- Laboratory of Biomathematics, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Bartos
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Department of Stomatology, General University Hospital in Prague, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Eva Zabrodska
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Barbora Sankova
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Alena Kvasilova
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Hana Kolesova
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Laboratory of Developmental Cardiology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - David Sedmera
- Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Laboratory of Developmental Cardiology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
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2
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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [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: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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3
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Pierre M, Djemai M, Chapotte-Baldacci CA, Pouliot V, Puymirat J, Boutjdir M, Chahine M. Cardiac involvement in patient-specific induced pluripotent stem cells of myotonic dystrophy type 1: unveiling the impact of voltage-gated sodium channels. Front Physiol 2023; 14:1258318. [PMID: 37791351 PMCID: PMC10544896 DOI: 10.3389/fphys.2023.1258318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/28/2023] [Indexed: 10/05/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a genetic disorder that causes muscle weakness and myotonia. In DM1 patients, cardiac electrical manifestations include conduction defects and atrial fibrillation. DM1 results in the expansion of a CTG transcribed into CUG-containing transcripts that accumulate in the nucleus as RNA foci and alter the activity of several splicing regulators. The underlying pathological mechanism involves two key RNA-binding proteins (MBNL and CELF) with expanded CUG repeats that sequester MBNL and alter the activity of CELF resulting in spliceopathy and abnormal electrical activity. In the present study, we identified two DM1 patients with heart conduction abnormalities and characterized their hiPSC lines. Two differentiation protocols were used to investigate both the ventricular and the atrial electrophysiological aspects of DM1 and unveil the impact of the mutation on voltage-gated ion channels, electrical activity, and calcium homeostasis in DM1 cardiomyocytes derived from hiPSCs. Our analysis revealed the presence of molecular hallmarks of DM1, including the accumulation of RNA foci and sequestration of MBNL1 in DM1 hiPSC-CMs. We also observed mis-splicing of SCN5A and haploinsufficiency of DMPK. Furthermore, we conducted separate characterizations of atrial and ventricular electrical activity, conduction properties, and calcium homeostasis. Both DM1 cell lines exhibited reduced density of sodium and calcium currents, prolonged action potential duration, slower conduction velocity, and impaired calcium transient propagation in both ventricular and atrial cardiomyocytes. Notably, arrhythmogenic events were recorded, including both ventricular and atrial arrhythmias were observed in the two DM1 cell lines. These findings enhance our comprehension of the molecular mechanisms underlying DM1 and provide valuable insights into the pathophysiology of ventricular and atrial involvement.
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Affiliation(s)
| | | | | | | | - Jack Puymirat
- LOEX, CHU de Québec-Université Laval Research Center, Quebec City, QC, Canada
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
- Departments of Cell Biology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, United States
- Department of Medicine, New York University Grossman School of Medicine, New York, NY, United States
| | - Mohamed Chahine
- CERVO Research Center, Quebec City, QC, Canada
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
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4
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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5
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Chen H, Li T, Wu Y, Wang X, Wang M, Wang X, Fang X. Association between single-nucleotide polymorphisms of NKX2.5 and congenital heart disease in Chinese population: A meta-analysis. Open Life Sci 2022; 17:473-482. [PMID: 35647298 PMCID: PMC9102305 DOI: 10.1515/biol-2022-0058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/18/2022] [Accepted: 03/03/2022] [Indexed: 11/15/2022] Open
Abstract
Abstract
NKX2.5 is a transcription factor that plays a key role in cardiovascular growth and development. Several independent studies have been previously conducted to investigate the association between the single-nucleotide polymorphism (SNP) 606G >C (rs3729753) in the coding region of NKX2.5 and congenital heart disease (CHD). However, the results of these studies have been inconsistent. Therefore, the present study aimed to reveal the relationship between NKX2.5 SNP 606G >C and the risk of CHD as possible in the Chinese population through meta-analysis. After retrieving related articles in PubMed, MEDLINE, EMBASE, Web of science, Cochrane, China National Knowledge Infrastructure, Wanfang DATA, and VIP database until August 2021, a total of eight studies were included in the present meta-analysis. The qualified research data were then merged into allele, dominant, recessive, heterozygous, homozygous, and additive models. Overall results of the current meta-analysis showed that 606G >C was not associated with CHD of the Chinese population in any model. In addition, subgroup analysis based on CHD type gave the same negative result. Results of sensitivity analysis showed that there was no significant correlation after the deletion of each study. Furthermore, it was noted that the results were negative and the heterogeneity was not significant. In conclusion, it was evident that NKX2-5 SNP 606G >C may not lead to the risk of CHD in Chinese population.
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Affiliation(s)
- Huan Chen
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University , Changsha , Hunan , China
| | - Tianjiao Li
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University , Changsha , Hunan , China
| | - Yuqing Wu
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University , Changsha , Hunan , China
| | - Xi Wang
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University , Changsha , Hunan , China
| | - Mingyuan Wang
- Department of Pathophysiology, Xiangya Medical College, Central South University , Changsha , Hunan , China
| | - Xin Wang
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University , Changsha , Hunan , China
| | - Xiaoling Fang
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University , Changsha , Hunan , China
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6
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Iop L, Iliceto S, Civieri G, Tona F. Inherited and Acquired Rhythm Disturbances in Sick Sinus Syndrome, Brugada Syndrome, and Atrial Fibrillation: Lessons from Preclinical Modeling. Cells 2021; 10:3175. [PMID: 34831398 PMCID: PMC8623957 DOI: 10.3390/cells10113175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 12/12/2022] Open
Abstract
Rhythm disturbances are life-threatening cardiovascular diseases, accounting for many deaths annually worldwide. Abnormal electrical activity might arise in a structurally normal heart in response to specific triggers or as a consequence of cardiac tissue alterations, in both cases with catastrophic consequences on heart global functioning. Preclinical modeling by recapitulating human pathophysiology of rhythm disturbances is fundamental to increase the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and clinical management. In silico, in vivo, and in vitro models found variable application to dissect many congenital and acquired rhythm disturbances. In the copious list of rhythm disturbances, diseases of the conduction system, as sick sinus syndrome, Brugada syndrome, and atrial fibrillation, have found extensive preclinical modeling. In addition, the electrical remodeling as a result of other cardiovascular diseases has also been investigated in models of hypertrophic cardiomyopathy, cardiac fibrosis, as well as arrhythmias induced by other non-cardiac pathologies, stress, and drug cardiotoxicity. This review aims to offer a critical overview on the effective ability of in silico bioinformatic tools, in vivo animal studies, in vitro models to provide insights on human heart rhythm pathophysiology in case of sick sinus syndrome, Brugada syndrome, and atrial fibrillation and advance their safe and successful translation into the cardiology arena.
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Affiliation(s)
- Laura Iop
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Via Giustiniani, 2, I-35124 Padua, Italy; (S.I.); (G.C.)
| | | | | | - Francesco Tona
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Via Giustiniani, 2, I-35124 Padua, Italy; (S.I.); (G.C.)
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7
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Hamano M, Nomura S, Iida M, Komuro I, Yamanishi Y. Prediction of single-cell mechanisms for disease progression in hypertrophic remodelling by a trans-omics approach. Sci Rep 2021; 11:8112. [PMID: 33854108 PMCID: PMC8047020 DOI: 10.1038/s41598-021-86821-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 03/18/2021] [Indexed: 12/24/2022] Open
Abstract
Heart failure is a heterogeneous disease with multiple risk factors and various pathophysiological types, which makes it difficult to understand the molecular mechanisms involved. In this study, we proposed a trans-omics approach for predicting molecular pathological mechanisms of heart failure and identifying marker genes to distinguish heterogeneous phenotypes, by integrating multiple omics data including single-cell RNA-seq, ChIP-seq, and gene interactome data. We detected a significant increase in the expression level of natriuretic peptide A (Nppa), after stress loading with transverse aortic constriction (TAC), and showed that cardiomyocytes with high Nppa expression displayed specific gene expression patterns. Multiple NADH ubiquinone complex family, which are associated with the mitochondrial electron transport system, were negatively correlated with Nppa expression during the early stages of cardiac hypertrophy. Large-scale ChIP-seq data analysis showed that Nkx2-5 and Gtf2b were transcription factors characteristic of high-Nppa-expressing cardiomyocytes. Nppa expression levels may, therefore, represent a useful diagnostic marker for heart failure.
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Affiliation(s)
- Momoko Hamano
- Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Seitaro Nomura
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan.,Genome Science Division, Research Center for Advanced Science and Technologies, The University of Tokyo, Tokyo, 153-0041, Japan
| | - Midori Iida
- Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Issei Komuro
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan
| | - Yoshihiro Yamanishi
- Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan.
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8
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Bousalis D, Lacko CS, Hlavac N, Alkassis F, Wachs RA, Mobini S, Schmidt CE, Kasahara H. Extracellular Matrix Disparities in an Nkx2-5 Mutant Mouse Model of Congenital Heart Disease. Front Cardiovasc Med 2020; 7:93. [PMID: 32548129 PMCID: PMC7272573 DOI: 10.3389/fcvm.2020.00093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/29/2020] [Indexed: 12/19/2022] Open
Abstract
Congenital heart disease (CHD) affects almost one percent of all live births. Despite diagnostic and surgical reparative advances, the causes and mechanisms of CHD are still primarily unknown. The extracellular matrix plays a large role in cell communication, function, and differentiation, and therefore likely plays a role in disease development and pathophysiology. Cell adhesion and gap junction proteins, such as integrins and connexins, are also essential to cellular communication and behavior, and could interact directly (integrins) or indirectly (connexins) with the extracellular matrix. In this work, we explore disparities in the expression and spatial patterning of extracellular matrix, adhesion, and gap junction proteins between wild type and Nkx2-5 +/R52G mutant mice. Decellularization and proteomic analysis, Western blotting, histology, immunostaining, and mechanical assessment of embryonic and neonatal wild type and Nkx2-5 mutant mouse hearts were performed. An increased abundance of collagen IV, fibronectin, and integrin β-1 was found in Nkx2-5 mutant neonatal mouse hearts, as well as increased expression of connexin 43 in embryonic mutant hearts. Furthermore, a ventricular noncompaction phenotype was observed in both embryonic and neonatal mutant hearts, as well as spatial disorganization of ECM proteins collagen IV and laminin in mutant hearts. Characterizing such properties in a mutant mouse model provides valuable information that can be applied to better understanding the mechanisms of congenital heart disease.
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Affiliation(s)
- Deanna Bousalis
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Christopher S Lacko
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Nora Hlavac
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Fariz Alkassis
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States
| | - Rebecca A Wachs
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Sahba Mobini
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Madrid, Spain.,Centro de Biología Molecular Severo Ochoa (CBMSO, UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Christine E Schmidt
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Hideko Kasahara
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States
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9
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Dupays L, Towers N, Wood S, David A, Stuckey DJ, Mohun T. Furin, a transcriptional target of NKX2-5, has an essential role in heart development and function. PLoS One 2019; 14:e0212992. [PMID: 30840660 PMCID: PMC6402701 DOI: 10.1371/journal.pone.0212992] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 02/13/2019] [Indexed: 11/22/2022] Open
Abstract
The homeodomain transcription factor NKX2-5 is known to be essential for both normal heart development and for heart function. But little is yet known about the identities of its downstream effectors or their function during differentiation of cardiac progenitor cells (CPCs). We have used transgenic analysis and CRISPR-mediated ablation to identify a cardiac enhancer of the Furin gene. The Furin gene, encoding a proprotein convertase, is directly repressed by NKX2-5. Deletion of Furin in CPCs is embryonic lethal, with mutant hearts showing a range of abnormalities in the outflow tract. Those defects are associated with a reduction in proliferation and premature differentiation of the CPCs. Deletion of Furin in differentiated cardiomyocytes results in viable adult mutant mice showing an elongation of the PR interval, a phenotype that is consistent with the phenotype of mice and human mutant for Nkx2-5. Our results show that Furin mediate some aspects of Nkx2-5 function in the heart.
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Affiliation(s)
- Laurent Dupays
- The Francis Crick Institute, London, United Kingdom
- * E-mail: (LD); (TM)
| | - Norma Towers
- The Francis Crick Institute, London, United Kingdom
| | - Sophie Wood
- The Francis Crick Institute, London, United Kingdom
| | - Anna David
- Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
| | - Daniel J. Stuckey
- Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
| | - Timothy Mohun
- The Francis Crick Institute, London, United Kingdom
- * E-mail: (LD); (TM)
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10
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Horton AJ, Brooker J, Streitfeld WS, Flessa ME, Pillai B, Simpson R, Clark CD, Gooz MB, Sutton KK, Foley AC, Lee KH. Nkx2-5 Second Heart Field Target Gene Ccdc117 Regulates DNA Metabolism and Proliferation. Sci Rep 2019; 9:1738. [PMID: 30742009 PMCID: PMC6370788 DOI: 10.1038/s41598-019-39078-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/13/2018] [Indexed: 11/08/2022] Open
Abstract
The cardiac transcription factor Nkx2-5 is essential for normal outflow tract (OFT) and right ventricle (RV) development. Nkx2-5-/- null mouse embryos display severe OFT and RV hypoplasia and a single ventricle phenotype due to decreased proliferation of Second Heart Field (SHF) cells, a pool of cardiac progenitors present in anterior pharyngeal arch mesoderm at mid-gestation. However, definition of the precise role of Nkx2-5 in facilitating SHF expansion is incomplete. We have found that Nkx2-5 positively and directly regulates a novel target gene, Ccdc117, in cells of the SHF at these stages. The nuclear/mitotic spindle associated protein Ccdc117 interacts with the MIP18/MMS19 cytoplasmic iron-sulfur (FeS) cluster assembly (CIA) complex, which transfers critical FeS clusters to several key enzymes with functions in DNA repair and replication. Loss of cellular Ccdc117 expression results in reduced proliferation rates associated with a delay at the G1-S transition, decreased rates of DNA synthesis, and unresolved DNA damage. These results implicate a novel role for Nkx2-5 in the regulation of cell cycle events in the developing heart, through Ccdc117's interaction with elements of the CIA pathway and the facilitation of DNA replication during SHF expansion.
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Affiliation(s)
- Anthony J Horton
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - John Brooker
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - William S Streitfeld
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Meaghan E Flessa
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Balakrishnan Pillai
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Raychel Simpson
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Christopher D Clark
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Monika B Gooz
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Kimberly K Sutton
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Ann C Foley
- Regenerative Medicine and Cell Biology Department, Medical University of South Carolina, Charleston, SC, 29425, USA
- Bioengineering Department, Clemson University - MUSC, Charleston, SC, 29425, USA
| | - Kyu-Ho Lee
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA.
- Regenerative Medicine and Cell Biology Department, Medical University of South Carolina, Charleston, SC, 29425, USA.
- Bioengineering Department, Clemson University - MUSC, Charleston, SC, 29425, USA.
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11
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Deletion of Nkx2-5 in trabecular myocardium reveals the developmental origins of pathological heterogeneity associated with ventricular non-compaction cardiomyopathy. PLoS Genet 2018; 14:e1007502. [PMID: 29979676 PMCID: PMC6051668 DOI: 10.1371/journal.pgen.1007502] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 07/18/2018] [Accepted: 06/19/2018] [Indexed: 12/20/2022] Open
Abstract
Left ventricular non-compaction (LVNC) is a rare cardiomyopathy associated with a hypertrabeculated phenotype and a large spectrum of symptoms. It is still unclear whether LVNC results from a defect of ventricular trabeculae development and the mechanistic basis that underlies the varying severity of this pathology is unknown. To investigate these issues, we inactivated the cardiac transcription factor Nkx2-5 in trabecular myocardium at different stages of trabecular morphogenesis using an inducible Cx40-creERT2 allele. Conditional deletion of Nkx2-5 at embryonic stages, during trabecular formation, provokes a severe hypertrabeculated phenotype associated with subendocardial fibrosis and Purkinje fiber hypoplasia. A milder phenotype was observed after Nkx2-5 deletion at fetal stages, during trabecular compaction. A longitudinal study of cardiac function in adult Nkx2-5 conditional mutant mice demonstrates that excessive trabeculation is associated with complex ventricular conduction defects, progressively leading to strain defects, and, in 50% of mutant mice, to heart failure. Progressive impaired cardiac function correlates with conduction and strain defects independently of the degree of hypertrabeculation. Transcriptomic analysis of molecular pathways reflects myocardial remodeling with a larger number of differentially expressed genes in the severe versus mild phenotype and identifies Six1 as being upregulated in hypertrabeculated hearts. Our results provide insights into the etiology of LVNC and link its pathogenicity with compromised trabecular development including compaction defects and ventricular conduction system hypoplasia. During fetal heart morphogenesis, formation of the mature ventricular wall requires coordinated compaction of the inner trabecular layer and growth of the outer layer of myocardium. Arrested trabecular development has been implicated in the pathogenesis of hypertrabeculation associated with ventricular non-compaction cardiomyopathy. However much uncertainty still exists among clinicians concerning the physiopathology of ventricular non-compaction cardiomyopathy, including its clinical characteristics, prognosis, classification and even the definition of hypertrabeculation. In particular, distinguishing between pathological and non-pathological subtypes of non-compaction is currently a major issue. Here we show that deletion of the gene encoding the transcription factor Nkx2-5 at critical steps during trabecular development recapitulates pathological features of hypertrabeculation, providing the first model of ventricular non-compaction cardiomyopathy in adult mice. We demonstrate that excessive trabeculation due to failure of trabecular compaction during fetal development is associated with Purkinje fiber hypoplasia and subendocardial fibrosis. Longitudinal functional studies reveal that these mice present all the clinical signs of symptomatic left ventricular non-compaction cardiomyopathy, including conduction defects, strain defects and progressive heart failure. Our results, including transcriptomic analysis, suggest that pathological features of non-compaction are primarily developmental defects. This study clarifies the origin of the pathological outcomes associated with LVNC and may provide helpful information for clinicians concerning the etiology of this rare cardiomyopathy.
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12
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Pursani V, Bhartiya D, Tanavde V, Bashir M, Sampath P. Transcriptional activator DOT1L putatively regulates human embryonic stem cell differentiation into the cardiac lineage. Stem Cell Res Ther 2018; 9:97. [PMID: 29631608 PMCID: PMC5891944 DOI: 10.1186/s13287-018-0810-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 02/12/2018] [Accepted: 02/20/2018] [Indexed: 01/09/2023] Open
Abstract
Background Commitment of pluripotent stem cells into differentiated cells and associated gene expression necessitate specific epigenetic mechanisms that modify the DNA and corresponding histone proteins to render the chromatin in an open or closed state. This in turn dictates the associated genetic machinery, including transcription factors, acknowledging the cellular signals provided. Activating histone methyltransferases represent crucial enzymes in the epigenetic machinery that cause transcription initiation by delivering the methyl mark on histone proteins. A number of studies have evidenced the vital role of one such histone modifier, DOT1L, in transcriptional regulation. Involvement of DOT1L in differentiating pluripotent human embryonic stem (hES) cells into the cardiac lineage has not yet been investigated. Methods The study was conducted on in-house derived (KIND1) and commercially available (HES3) human embryonic stem cell lines. Chromatin immunoprecipitation (ChIP) was performed followed by sequencing to uncover the cardiac genes harboring the DOT1L specific mark H3K79me2. Following this, dual immunofluorescence was employed to show the DOT1L co-occupancy along with the cardiac progenitor specific marker. DOT1L was knocked down by siRNA to further confirm its role during cardiac differentiation. Results ChIP sequencing revealed a significant number of peaks characterizing H3K79me2 occupancy in the proximity of the transcription start site. This included genes like MYOF, NR2F2, NKX2.5, and HAND1 in cardiac progenitors and cardiomyocytes, and POU5F1 and NANOG in pluripotent hES cells. Consistent with this observation, we also show that DOT1L co-localizes with the master cardiac transcription factor NKX2.5, suggesting its direct involvement during gene activation. Knockdown of DOT1L did not alter the pluripotency of hES cells, but it led to the disruption of cardiac differentiation observed morphologically as well as at transcript and protein levels. Conclusions Collectively, our data suggests the crucial role of H3K79me2 methyltransferase DOT1L for activation of NKX2.5 during the cardiac differentiation of hES cells. Electronic supplementary material The online version of this article (10.1186/s13287-018-0810-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Varsha Pursani
- Stem Cell Biology Department, ICMR-National Institute for Research in Reproductive Health, J.M. Street, Parel, Mumbai, Maharashtra, 400 012, India
| | - Deepa Bhartiya
- Stem Cell Biology Department, ICMR-National Institute for Research in Reproductive Health, J.M. Street, Parel, Mumbai, Maharashtra, 400 012, India.
| | - Vivek Tanavde
- Division of Biological & Life Sciences, School of Arts & Sciences, Ahmedabad University, Ahmedabad, 380009, India.,Genome and Gene Expression Data Analysis Division, A* Star-Bioinformatics Institute, Singapore, 138671, Singapore
| | - Mohsin Bashir
- Division of Translational Control of Disease, A* Star-Institute of Medical Biology, Singapore, 138648, Singapore
| | - Prabha Sampath
- Division of Translational Control of Disease, A* Star-Institute of Medical Biology, Singapore, 138648, Singapore
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13
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Xu JH, Gu JY, Guo YH, Zhang H, Qiu XB, Li RG, Shi HY, Liu H, Yang XX, Xu YJ, Qu XK, Yang YQ. Prevalence and Spectrum of NKX2-5 Mutations Associated With Sporadic Adult-Onset Dilated Cardiomyopathy. Int Heart J 2017; 58:521-529. [PMID: 28690296 DOI: 10.1536/ihj.16-440] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dilated cardiomyopathy (DCM), the most common form of primary myocardial disease, is a leading cause of congestive heart failure and the most common indication for heart transplantation. Recently, NKX2-5 mutations have been involved in the pathogenesis of familial DCM. However, the prevalence and spectrum of NKX2-5 mutations associated with sporadic DCM remain to be evaluated. In this study, the coding regions and flanking introns of the NKX2-5 gene, which encodes a cardiac transcription factor pivotal for cardiac development and structural remodeling, were sequenced in 210 unrelated patients with sporadic adult-onset DCM. A total of 300 unrelated healthy individuals used as controls were also genotyped for NKX2-5. The functional effect of the mutant NKX2-5 was investigated using a dual-luciferase reporter assay system. As a result, two novel heterozygous NKX2-5 mutations, p.R139W and p.E167X, were identified in 2 unrelated patients with sporadic adult-onset DCM, with a mutational prevalence of approximately 0.95%. The mutations were absent in 600 referential chromosomes and the altered amino acids were completely conserved evolutionarily across species. Functional assays revealed that the NKX2-5 mutants were associated with significantly reduced transcriptional activity. Furthermore, the mutations abrogated the synergistic activation between NKX2-5 and GATA4 as well as TBX20, two other cardiac key transcription factors that have been causally linked to adult-onset DCM. This study is the first to associate NKX2-5 loss-of-function mutations with enhanced susceptibility to sporadic DCM, which provides novel insight into the molecular etiology underpinning DCM, and suggests the potential implications for the genetic counseling and personalized treatment of the DCM patients.
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Affiliation(s)
- Jia-Hong Xu
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine
| | - Jian-Yun Gu
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine
| | - Yu-Han Guo
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine
| | - Hong Zhang
- Department of Pharmacy, Tongji Hospital, Tongji University School of Medicine
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Ruo-Gu Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Hong-Yu Shi
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Hua Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Xiao-Xiao Yang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Xin-Kai Qu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University.,Department of Cardiovascular Research Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University.,Department of Central Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University
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14
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Abstract
The generation and propagation of the cardiac impulse is the central function of the cardiac conduction system (CCS). Impulse initiation occurs in nodal tissues that have high levels of automaticity, but slow conduction properties. Rapid impulse propagation is a feature of the ventricular conduction system, which is essential for synchronized contraction of the ventricular chambers. When functioning properly, the CCS produces ~2.4 billion heartbeats during a human lifetime and orchestrates the flow of cardiac impulses, designed to maximize cardiac output. Abnormal impulse initiation or propagation can result in brady- and tachy-arrhythmias, producing an array of symptoms, including syncope, heart failure or sudden cardiac death. Underlying the functional diversity of the CCS are gene regulatory networks that direct cell fate towards a nodal or a fast conduction gene program. In this review, we will discuss our current understanding of the transcriptional networks that dictate the components of the CCS, the growth factor-dependent signaling pathways that orchestrate some of these transcriptional hierarchies and the effect of aberrant transcription factor expression on mammalian conduction disease.
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15
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Furtado MB, Wilmanns JC, Chandran A, Perera J, Hon O, Biben C, Willow TJ, Nim HT, Kaur G, Simonds S, Wu Q, Willians D, Salimova E, Plachta N, Denegre JM, Murray SA, Fatkin D, Cowley M, Pearson JT, Kaye D, Ramialison M, Harvey RP, Rosenthal NA, Costa MW. Point mutations in murine Nkx2-5 phenocopy human congenital heart disease and induce pathogenic Wnt signaling. JCI Insight 2017; 2:e88271. [PMID: 28352650 DOI: 10.1172/jci.insight.88271] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the Nkx2-5 gene are a main cause of congenital heart disease. Several studies have addressed the phenotypic consequences of disrupting the Nkx2-5 gene locus, although animal models to date failed to recapitulate the full spectrum of the human disease. Here, we describe a new Nkx2-5 point mutation murine model, akin to its human counterpart disease-generating mutation. Our model fully reproduces the morphological and physiological clinical presentations of the disease and reveals an understudied aspect of Nkx2-5-driven pathology, a primary right ventricular dysfunction. We further describe the molecular consequences of disrupting the transcriptional network regulated by Nkx2-5 in the heart and show that Nkx2-5-dependent perturbation of the Wnt signaling pathway promotes heart dysfunction through alteration of cardiomyocyte metabolism. Our data provide mechanistic insights on how Nkx2-5 regulates heart function and metabolism, a link in the study of congenital heart disease, and confirms that our models are the first murine genetic models to our knowledge to present all spectra of clinically relevant adult congenital heart disease phenotypes generated by NKX2-5 mutations in patients.
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Affiliation(s)
- Milena B Furtado
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Julia C Wilmanns
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia.,Department of Cardiology and Angiology, Medical School Hannover, Hannover, Germany
| | - Anjana Chandran
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Joelle Perera
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Olivia Hon
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - Christine Biben
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | | | - Hieu T Nim
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Gurpreet Kaur
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | | | - Qizhu Wu
- Monash Biomedical Imaging, Monash University, Clayton, Australia
| | - David Willians
- Heart Failure Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Ekaterina Salimova
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | | | | | | | - Diane Fatkin
- Molecular Cardiology, Victor Chang Cardiac Research Institute, Darlinghurst, Australia.,Faculty of Medicine and School of Biological and Biomolecular Sciences, University of New South Wales, Kensington, Australia.,Cardiology Department, St. Vincent's Hospital, Darlinghurst, Australia
| | | | - James T Pearson
- Department of Physiology.,Monash Biomedical Imaging, Monash University, Clayton, Australia
| | - David Kaye
- Heart Failure Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Mirana Ramialison
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Richard P Harvey
- Faculty of Medicine and School of Biological and Biomolecular Sciences, University of New South Wales, Kensington, Australia.,Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | - Nadia A Rosenthal
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Mauro W Costa
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
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16
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Choy L, Yeo JM, Tse V, Chan SP, Tse G. Cardiac disease and arrhythmogenesis: Mechanistic insights from mouse models. IJC HEART & VASCULATURE 2016; 12:1-10. [PMID: 27766308 PMCID: PMC5064289 DOI: 10.1016/j.ijcha.2016.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 05/02/2016] [Indexed: 12/19/2022]
Abstract
The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony. Last but not least, pharmacological models, despite being simplistic, have enabled us to understand the physiological mechanisms of arrhythmias and evaluate the anti-arrhythmic properties of experimental agents, such as gap junction modulators, that may be exert therapeutic effects in other cardiac diseases. In this article, we examine these in turn, demonstrating that primary inherited arrhythmic syndromes are now recognized to be more complex than abnormality in a particular ion channel, involving alterations in gene expression and structural remodelling. Conversely, in cardiomyopathies and heart failure, mutations in ion channels and proteins have been identified as underlying causes, and electrophysiological remodelling are recognized pathological features. Transgenic techniques causing mutagenesis in mice are extremely powerful in dissecting the relative contributions of different genes play in producing disease phenotypes. Mouse models can serve as useful systems in which to explore how protein defects contribute to arrhythmias and direct future therapy.
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Affiliation(s)
- Lois Choy
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Jie Ming Yeo
- School of Medicine, Imperial College London, SW7 2AZ, UK
| | - Vivian Tse
- Department of Physiology, McGill University, Canada
| | - Shing Po Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Gary Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
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17
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Abstract
SUMOylation is a ubiquitin-related transient posttranslational modification pathway catalyzing the conjugation of small ubiquitin-like modifier (SUMO) proteins (SUMO1, SUMO2, and SUMO3) to lysine residues of proteins. SUMOylation targets a wide variety of cellular regulators and thereby affects a multitude of different cellular processes. SUMO/sentrin-specific proteases are able to remove SUMOs from targets, contributing to a tight control of SUMOylated proteins. Genetic and cell biological experiments indicate a critical role of balanced SUMOylation/deSUMOylation for proper cardiac development, metabolism, and stress adaptation. Here, we review the current knowledge about SUMOylation/deSUMOylation in the heart and provide an integrated picture of cardiac functions of the SUMO system under physiologic or pathologic conditions. We also describe potential therapeutic approaches targeting the SUMO machinery to combat heart disease.
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Affiliation(s)
- Luca Mendler
- From the Institute of Biochemistry II, Goethe University, Medical School, Frankfurt, Germany (L.M., S.M.); Institute of Biochemistry, Faculty of General Medicine, University of Szeged, Szeged, Hungary (L.M.); and Department I - Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (T.B.)
| | - Thomas Braun
- From the Institute of Biochemistry II, Goethe University, Medical School, Frankfurt, Germany (L.M., S.M.); Institute of Biochemistry, Faculty of General Medicine, University of Szeged, Szeged, Hungary (L.M.); and Department I - Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (T.B.).
| | - Stefan Müller
- From the Institute of Biochemistry II, Goethe University, Medical School, Frankfurt, Germany (L.M., S.M.); Institute of Biochemistry, Faculty of General Medicine, University of Szeged, Szeged, Hungary (L.M.); and Department I - Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (T.B.).
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18
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Nisbet AM, Camelliti P, Walker NL, Burton FL, Cobbe SM, Kohl P, Smith GL. Prolongation of atrio-ventricular node conduction in a rabbit model of ischaemic cardiomyopathy: Role of fibrosis and connexin remodelling. J Mol Cell Cardiol 2016; 94:54-64. [PMID: 27021518 PMCID: PMC4873602 DOI: 10.1016/j.yjmcc.2016.03.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 03/16/2016] [Accepted: 03/23/2016] [Indexed: 11/26/2022]
Abstract
Conduction abnormalities are frequently associated with cardiac disease, though the mechanisms underlying the commonly associated increases in PQ interval are not known. This study uses a chronic left ventricular (LV) apex myocardial infarction (MI) model in the rabbit to create significant left ventricular dysfunction (LVD) 8 weeks post-MI. In vivo studies established that the PQ interval increases by approximately 7 ms (10%) with no significant change in average heart rate. Optical mapping of isolated Langendorff perfused rabbit hearts recapitulated this result: time to earliest activation of the LV was increased by 14 ms (16%) in the LVD group. Intra-atrial and LV transmural conduction times were not altered in the LVD group. Isolated AVN preparations from the LVD group demonstrated a significantly longer conduction time (by approximately 20 ms) between atrial and His electrograms than sham controls across a range of pacing cycle lengths. This difference was accompanied by increased effective refractory period and Wenckebach cycle length, suggesting significantly altered AVN electrophysiology post-MI. The AVN origin of abnormality was further highlighted by optical mapping of the isolated AVN. Immunohistochemistry of AVN preparations revealed increased fibrosis and gap junction protein (connexin43 and 40) remodelling in the AVN of LVD animals compared to sham. A significant increase in myocyte–non-myocyte connexin co-localization was also observed after LVD. These changes may increase the electrotonic load experienced by AVN muscle cells and contribute to slowed conduction velocity within the AVN. Chronic myocardial infarction (MI) causes changes in atrio-ventricular node (AVN) function. Isolated hearts post-MI show delays in ventricular activation due to slowed conduction via the AVN. Isolated AVN preparations demonstrated AVN electrical remodelling post-MI. Electrical remodelling is associated with fibrosis and altered expression of connexins in the AVN. AVN dysfunction post-MI is caused by localized functional and structural remodelling.
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Affiliation(s)
- Ashley M Nisbet
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8QQ, UK
| | - Patrizia Camelliti
- School of Biosciences and Medicine, University of Surrey, Guildford, GU2 7XH, UK.
| | - Nicola L Walker
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8QQ, UK
| | - Francis L Burton
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8QQ, UK
| | - Stuart M Cobbe
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8QQ, UK
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, Medical School of the University of Freiburg, Germany; Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield UB9 6JH, UK
| | - Godfrey L Smith
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8QQ, UK
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19
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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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20
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Yuan F, Qiu XB, Li RG, Qu XK, Wang J, Xu YJ, Liu X, Fang WY, Yang YQ, Liao DN. A novel NKX2-5 loss-of-function mutation predisposes to familial dilated cardiomyopathy and arrhythmias. Int J Mol Med 2014; 35:478-86. [PMID: 25503402 DOI: 10.3892/ijmm.2014.2029] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 12/05/2014] [Indexed: 01/08/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is the most prevalent type of primary myocardial disease, which is the third most common cause of heart failure and the most frequent reason for heart transplantation. Aggregating evidence demonstrates that genetic risk factors are involved in the pathogenesis of idiopathic DCM. Nevertheless, DCM is of remarkable genetic heterogeneity and the genetic defects underpinning DCM in an overwhelming majority of patients remain unknown. In the present study, the whole coding exons and splice junction sites of the NKX2-5 gene, which encodes a homeodomain transcription factor crucial for cardiac development and structural remodeling, were sequenced in 130 unrelated patients with idiopathic DCM. The available relatives of the index patient harboring an identified mutation and 200 unrelated ethnically matched healthy individuals used as controls were genotyped for the NKX2-5 gene. The functional effect of the mutant NKX2-5 was characterized in contrast to its wild-type counterpart using a dual-luciferase reporter assay system. As a result, a novel heterozygous NKX2-5 mutation, p.S146W, was identified in a family with DCM inherited as an autosomal dominant trait, which co-segregated with DCM in the family with complete penetrance. Notably, the mutation carriers also had arrhythmias, such as paroxysmal atrial fibrillation and atrioventricular block. The missense mutation was absent in 400 reference chromosomes and the altered amino acid was completely conserved evolutionarily among species. Functional analysis revealed that the NKX2-5 mutant was associated with a significantly reduced transcriptional activity. The findings expand the mutational spectrum of NKX2-5 linked to DCM and provide novel insight into the molecular mechanisms underlying DCM, contributing to the antenatal prophylaxis and allele-specific management of DCM.
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Affiliation(s)
- Fang Yuan
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - Ruo-Gu Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - Xin-Kai Qu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - Juan Wang
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, P.R. China
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - Wei-Yi Fang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
| | - De-Ning Liao
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
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21
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Bressan M, Yang PB, Louie JD, Navetta AM, Garriock RJ, Mikawa T. Reciprocal myocardial-endocardial interactions pattern the delay in atrioventricular junction conduction. Development 2014; 141:4149-57. [PMID: 25273084 DOI: 10.1242/dev.110007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Efficient blood flow depends on two developmental processes that occur within the atrioventricular junction (AVJ) of the heart: conduction delay, which entrains sequential chamber contraction; and valve formation, which prevents retrograde fluid movement. Defects in either result in severe congenital heart disease; however, little is known about the interplay between these two crucial developmental processes. Here, we show that AVJ conduction delay is locally assigned by the morphogenetic events that initiate valve formation. Our data demonstrate that physical separation from endocardial-derived factors prevents AVJ myocardium from becoming fast conducting. Mechanistically, this physical separation is induced by myocardial-derived factors that support cardiac jelly deposition at the onset of valve formation. These data offer a novel paradigm for conduction patterning, whereby reciprocal myocardial-endocardial interactions coordinate the processes of valve formation with establishment of conduction delay. This, in turn, synchronizes the electrophysiological and structural events necessary for the optimization of blood flow through the developing heart.
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Affiliation(s)
- Michael Bressan
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3120, USA
| | - PoAn Brian Yang
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3120, USA
| | - Jonathan D Louie
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3120, USA
| | - Alicia M Navetta
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3120, USA
| | - Robert J Garriock
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3120, USA
| | - Takashi Mikawa
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3120, USA
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22
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Zhang SS, Shaw RM. Trafficking highways to the intercalated disc: new insights unlocking the specificity of connexin 43 localization. ACTA ACUST UNITED AC 2014; 21:43-54. [PMID: 24460200 DOI: 10.3109/15419061.2013.876014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
With each heartbeat, billions of cardiomyocytes work in concert to propagate the electrical excitation needed to effectively circulate blood. Regulated expression and timely delivery of connexin proteins to form gap junctions at the specialized cell-cell contact region, known as the intercalated disc, is essential to ventricular cardiomyocyte coupling. We focus this review on several regulatory mechanisms that have been recently found to govern the lifecycle of connexin 43 (Cx43), the short-lived and most abundantly expressed connexin in cardiac ventricular muscle. The Cx43 lifecycle begins with gene expression, followed by oligomerization into hexameric channels, and then cytoskeletal-based transport toward the disc region. Once delivered, hemichannels interact with resident disc proteins and are organized to effect intercellular coupling. We highlight recent studies exploring regulation of Cx43 localization to the intercalated disc, with emphasis on alternatively translated Cx43 isoforms and cytoskeletal transport machinery that together regulate Cx43 gap junction coupling between cardiomyocytes.
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23
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Gladman JT, Yadava RS, Mandal M, Yu Q, Kim YK, Mahadevan MS. NKX2-5, a modifier of skeletal muscle pathology due to RNA toxicity. Hum Mol Genet 2014; 24:251-64. [PMID: 25168381 DOI: 10.1093/hmg/ddu443] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
RNA toxicity is implicated in a number of disorders; especially those associated with expanded repeat sequences, such as myotonic dystrophy (DM1). Previously, we have shown increased NKX2-5 expression in RNA toxicity associated with DM1. Here, we investigate the relationship between NKX2-5 expression and muscle pathology due to RNA toxicity. In skeletal muscle from mice with RNA toxicity and individuals with DM1, expression of Nkx2-5 or NKX2-5 and its downstream targets are significantly correlated with severity of histopathology. Using C2C12 myoblasts, we show that over-expression of NKX2-5 or mutant DMPK 3'UTR results in myogenic differentiation defects, which can be rescued by knockdown of Nkx2-5, despite continued toxic RNA expression. Furthermore, in a mouse model of NKX2-5 over-expression, we find defects in muscle regeneration after induced damage, similar to those seen in mice with RNA toxicity. Using mouse models of Nkx2-5 over-expression and depletion, we find that NKX2-5 levels modify disease phenotypes in mice with RNA toxicity.
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Affiliation(s)
- Jordan T Gladman
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ramesh S Yadava
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Mahua Mandal
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Qing Yu
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Yun K Kim
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Mani S Mahadevan
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
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24
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Ashraf H, Pradhan L, Chang EI, Terada R, Ryan NJ, Briggs LE, Chowdhury R, Zárate MA, Sugi Y, Nam HJ, Benson DW, Anderson RH, Kasahara H. A mouse model of human congenital heart disease: high incidence of diverse cardiac anomalies and ventricular noncompaction produced by heterozygous Nkx2-5 homeodomain missense mutation. ACTA ACUST UNITED AC 2014; 7:423-433. [PMID: 25028484 DOI: 10.1161/circgenetics.113.000281] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Heterozygous human mutations of NKX2-5 are highly penetrant and associated with varied congenital heart defects. The heterozygous knockout of murine Nkx2-5, in contrast, manifests less profound cardiac malformations, with low disease penetrance. We sought to study this apparent discrepancy between human and mouse genetics. Because missense mutations in the NKX2-5 homeodomain (DNA-binding domain) are the most frequently reported type of human mutation, we replicated this genetic defect in a murine knockin model. METHODS AND RESULTS We generated a murine model in a 129/Sv genetic background by knocking-in an Nkx2-5 homeodomain missense mutation previously identified in humans. The mutation was located at homeodomain position 52Arg→Gly (R52G). All the heterozygous neonatal Nkx2-5(+/R52G) mice demonstrated a prominent trabecular layer in the ventricular wall, so called noncompaction, along with diverse cardiac anomalies, including atrioventricular septal defects, Ebstein malformation of the tricuspid valve, and perimembranous and muscular ventricular septal defects. In addition, P10 Nkx2-5(+/R52G) mice demonstrated atrial sepal anomalies, with significant increase in the size of the interatrial communication and fossa ovalis, and decrease in the length of the flap valve compared with control Nkx2-5(+/+) or Nkx2-5(+/-) mice. CONCLUSIONS The results of our study demonstrate that heterozygous missense mutation in the murine Nkx2-5 homeodomain (R52G) is highly penetrant and result in pleiotropic cardiac effects. Thus, in contrast to heterozygous Nkx2-5 knockout mice, the effects of the heterozygous knockin mimic findings in humans with heterozygous missense mutation in NKX2-5 homeodomain.
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Affiliation(s)
- Hassan Ashraf
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Lagnajeet Pradhan
- Department of Bioengineering, University of Texas at Dallas, TX 75080
| | - Eileen I Chang
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Ryota Terada
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Nicole J Ryan
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Laura E Briggs
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Rajib Chowdhury
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Miguel A Zárate
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Yukiko Sugi
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Hyun-Joo Nam
- Department of Bioengineering, University of Texas at Dallas, TX 75080
| | - D Woodrow Benson
- Department of Pediatrics, Herma Heart Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | | | - Hideko Kasahara
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
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25
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Nakashima Y, Yanez DA, Touma M, Nakano H, Jaroszewicz A, Jordan MC, Pellegrini M, Roos KP, Nakano A. Nkx2-5 suppresses the proliferation of atrial myocytes and conduction system. Circ Res 2014; 114:1103-13. [PMID: 24563458 DOI: 10.1161/circresaha.114.303219] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
RATIONALE Tight control of cardiomyocyte proliferation is essential for the formation of four-chambered heart. Although human mutation of NKX2-5 is linked to septal defects and atrioventricular conduction abnormalities, early lethality and hemodynamic alteration in the mutant models have caused controversy as to whether Nkx2-5 regulates cardiomyocyte proliferation. OBJECTIVE In this study, we circumvented these limitations by atrial-restricted deletion of Nkx2-5. METHOD AND RESULTS Atrial-specific Nkx2-5 mutants died shortly after birth with hyperplastic working myocytes and conduction system including two nodes and internodal tracts. Multicolor reporter analysis revealed that Nkx2-5-null cardiomyocytes displayed clonal proliferative activity throughout the atria, indicating the suppressive role of Nkx2-5 in cardiomyocyte proliferation after chamber ballooning stages. Transcriptome analysis revealed that aberrant activation of Notch signaling underlies hyperproliferation of mutant cardiomyocytes, and forced activation of Notch signaling recapitulates hyperproliferation of working myocytes but not the conduction system. CONCLUSIONS Collectively, these data suggest that Nkx2-5 regulates the proliferation of atrial working and conduction myocardium in coordination with Notch pathway.
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Affiliation(s)
- Yasuhiro Nakashima
- From the Department of Molecular Cell and Developmental Biology (Y.N., D.A.Y., H.N., A.J., M.P., A.N.), Departments of Pediatrics and Molecular Cell and Integrative Physiology, David Geffen School of Medicine (M.T.), Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research (H.N., M.P., A.N.), Department of Physiology, David Geffen School of Medicine (M.C.J., K.P.R.), Molecular Biology Institute (M.P.), Institute of Genomics and Proteomics (M.P.), and Jonsson Comprehensive Cancer Center (A.N.), University of California, Los Angeles, Los Angeles, CA
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26
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Heart failure in congenital heart disease: the role of genes and hemodynamics. Pflugers Arch 2014; 466:1025-35. [DOI: 10.1007/s00424-014-1447-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 01/07/2014] [Indexed: 12/28/2022]
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27
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Transcriptional networks regulating the costamere, sarcomere, and other cytoskeletal structures in striated muscle. Cell Mol Life Sci 2013; 71:1641-56. [PMID: 24218011 DOI: 10.1007/s00018-013-1512-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/27/2013] [Accepted: 10/30/2013] [Indexed: 10/26/2022]
Abstract
Structural abnormalities in striated muscle have been observed in numerous transcription factor gain- and loss-of-function phenotypes in animal and cell culture model systems, indicating that transcription is important in regulating the cytoarchitecture. While most characterized cytoarchitectural defects are largely indistinguishable by histological and ultrastructural criteria, analysis of dysregulated gene expression in each mutant phenotype has yielded valuable information regarding specific structural gene programs that may be uniquely controlled by each of these transcription factors. Linking the formation and maintenance of each subcellular structure or subset of proteins within a cytoskeletal compartment to an overlapping but distinct transcription factor cohort may enable striated muscle to control cytoarchitectural function in an efficient and specific manner. Here we summarize the available evidence that connects transcription factors, those with established roles in striated muscle such as MEF2 and SRF, as well as other non-muscle transcription factors, to the regulation of a defined cytoskeletal structure. The notion that genes encoding proteins localized to the same subcellular compartment are coordinately transcriptionally regulated may prompt rationally designed approaches that target specific transcription factor pathways to correct structural defects in muscle disease.
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28
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Lee KY, Li M, Manchanda M, Batra R, Charizanis K, Mohan A, Warren SA, Chamberlain CM, Finn D, Hong H, Ashraf H, Kasahara H, Ranum LPW, Swanson MS. Compound loss of muscleblind-like function in myotonic dystrophy. EMBO Mol Med 2013; 5:1887-900. [PMID: 24293317 PMCID: PMC3914532 DOI: 10.1002/emmm.201303275] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 02/04/2023] Open
Abstract
Myotonic dystrophy (DM) is a multi-systemic disease that impacts cardiac and skeletal muscle as well as the central nervous system (CNS). DM is unusual because it is an RNA-mediated disorder due to the expression of toxic microsatellite expansion RNAs that alter the activities of RNA processing factors, including the muscleblind-like (MBNL) proteins. While these mutant RNAs inhibit MBNL1 splicing activity in heart and skeletal muscles, Mbnl1 knockout mice fail to recapitulate the full-range of DM symptoms in these tissues. Here, we generate mouse Mbnl compound knockouts to test the hypothesis that Mbnl2 functionally compensates for Mbnl1 loss. Although Mbnl1−/−; Mbnl2−/− double knockouts (DKOs) are embryonic lethal, Mbnl1−/−; Mbnl2+/− mice are viable but develop cardinal features of DM muscle disease including reduced lifespan, heart conduction block, severe myotonia and progressive skeletal muscle weakness. Mbnl2 protein levels are elevated in Mbnl1−/− knockouts where Mbnl2 targets Mbnl1-regulated exons. These findings support the hypothesis that compound loss of MBNL function is a critical event in DM pathogenesis and provide novel mouse models to investigate additional pathways disrupted in this RNA-mediated disease.
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Affiliation(s)
- Kuang-Yung Lee
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, USA; Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan
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29
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Costa MW, Guo G, Wolstein O, Vale M, Castro ML, Wang L, Otway R, Riek P, Cochrane N, Furtado M, Semsarian C, Weintraub RG, Yeoh T, Hayward C, Keogh A, Macdonald P, Feneley M, Graham RM, Seidman JG, Seidman CE, Rosenthal N, Fatkin D, Harvey RP. Functional characterization of a novel mutation in NKX2-5 associated with congenital heart disease and adult-onset cardiomyopathy. ACTA ACUST UNITED AC 2013; 6:238-47. [PMID: 23661673 DOI: 10.1161/circgenetics.113.000057] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The transcription factor NKX2-5 is crucial for heart development, and mutations in this gene have been implicated in diverse congenital heart diseases and conduction defects in mouse models and humans. Whether NKX2-5 mutations have a role in adult-onset heart disease is unknown. METHODS AND RESULTS Mutation screening was performed in 220 probands with adult-onset dilated cardiomyopathy. Six NKX2-5 coding sequence variants were identified, including 3 nonsynonymous variants. A novel heterozygous mutation, I184M, located within the NKX2-5 homeodomain, was identified in 1 family. A subset of family members had congenital heart disease, but there was an unexpectedly high prevalence of dilated cardiomyopathy. Functional analysis of I184M in vitro demonstrated a striking increase in protein expression when transfected into COS-7 cells or HL-1 cardiomyocytes because of reduced degradation by the Ubiquitin-proteasome system. In functional assays, DNA-binding activity of I184M was reduced, resulting in impaired activation of target genes despite increased expression levels of mutant protein. CONCLUSIONS Certain NKX2-5 homeodomain mutations show abnormal protein degradation via the Ubiquitin-proteasome system and partially impaired transcriptional activity. We propose that this class of mutation can impair heart development and mature heart function and contribute to NKX2-5-related cardiomyopathies with graded severity.
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Affiliation(s)
- Mauro W Costa
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.
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30
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Two novel and functional DNA sequence variants within an upstream enhancer of the human NKX2-5 gene in ventricular septal defects. Gene 2013; 524:152-5. [PMID: 23644027 DOI: 10.1016/j.gene.2013.04.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/27/2013] [Accepted: 04/04/2013] [Indexed: 01/08/2023]
Abstract
Mortality in patients with congenital heart disease (CHD) is significantly increased even with successful surgeries. The main causes are late cardiac complications, such as heart failure and arrhythmia, probably due to genetic defects. To date, genetic causes for CHD remain largely unknown. NKX2-5 gene encodes a highly conserved homeobox transcription factor, which is essential to the heart development in embryos and cardiac function in adults. Mutations in NKX2-5 gene have been implicated in diverse types of CHD, including ventricular septal defect (VSD). As NKX2-5 is a dosage-sensitive regulator, we have speculated that changed NKX2-5 levels may mediate CHD development by influencing cardiac gene regulatory network. In previous studies, we have analyzed the NKX2-5 gene promoter and a proximal enhancer in VSD patients. In the present study, we further genetically and functionally analyzed an upstream enhancer of the NKX2-5 gene in large cohorts of VSD patients (n=340) and controls (n=347). Two novel heterozygous DNA sequence variants (DSVs), g.17483576C>G and g.17483564C>T, were identified in three VSD patients, but none in controls. Functionally, these two DSVs significantly decreased the activity of the enhancer (P<0.01). Another novel heterozygous DSV, g.17483557Ins, was found in both VSD patients and controls with similar frequencies (P>0.05). Taken together, our data suggested that the DSVs within the upstream enhancer of the NKX2-5 gene may contribute to a small number of VSD. Therefore, genetic studies of CHD may provide insight into designing novel therapies for adult CHD patients.
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31
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Zhang SS, Shaw RM. Multilayered regulation of cardiac ion channels. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1833:876-85. [PMID: 23103513 PMCID: PMC3568256 DOI: 10.1016/j.bbamcr.2012.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/12/2012] [Accepted: 10/12/2012] [Indexed: 12/27/2022]
Abstract
Essential to beat-to-beat heart function is the ability for cardiomyocytes to propagate electrical excitation and generate contractile force. Both excitation and contractility depend on specific ventricular ion channels, which include the L-type calcium channel (LTCC) and the connexin 43 (Cx43) gap junction. Each of these two channels is localized to a distinct subdomain of the cardiomyocyte plasma membrane. In this review, we focus on regulatory mechanisms that govern the lifecycles of LTCC and Cx43, from their biogenesis in the nucleus to directed delivery to T-tubules and intercalated discs, respectively. We discuss recent findings on how alternative promoter usage, tissue-specific transcription, and alternative splicing determine precise ion channel expression levels within a cardiomyocyte. Moreover, recent work on microtubule and actin-dependent trafficking for Cx43 and LTCC are introduced. Lastly, we discuss how human cardiac disease phenotypes can be attributed to defects in distinct mechanisms of channel regulation at the level of gene expression and channel trafficking. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.
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Affiliation(s)
- Shan-Shan Zhang
- University of California, San Francisco, San Francisco, CA 94158, USA
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32
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Qin X, Xing Q, Ma L, Meng H, Liu Y, Pang S, Yan B. Genetic analysis of an enhancer of the NKX2-5 gene in ventricular septal defects. Gene 2012; 508:106-9. [DOI: 10.1016/j.gene.2012.07.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/01/2012] [Accepted: 07/13/2012] [Indexed: 01/23/2023]
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33
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Kaese S, Verheule S. Cardiac electrophysiology in mice: a matter of size. Front Physiol 2012; 3:345. [PMID: 22973235 PMCID: PMC3433738 DOI: 10.3389/fphys.2012.00345] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/09/2012] [Indexed: 12/27/2022] Open
Abstract
Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias.
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Affiliation(s)
- Sven Kaese
- Division of Experimental and Clinical Electrophysiology, Department of Cardiology and Angiology, University Hospital Münster Münster, Germany
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34
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Normal and abnormal development of the cardiac conduction system; implications for conduction and rhythm disorders in the child and adult. Differentiation 2012; 84:131-48. [DOI: 10.1016/j.diff.2012.04.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 04/16/2012] [Indexed: 11/20/2022]
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35
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Raveau M, Lignon JM, Nalesso V, Duchon A, Groner Y, Sharp AJ, Dembele D, Brault V, Hérault Y. The App-Runx1 region is critical for birth defects and electrocardiographic dysfunctions observed in a Down syndrome mouse model. PLoS Genet 2012; 8:e1002724. [PMID: 22693452 PMCID: PMC3364940 DOI: 10.1371/journal.pgen.1002724] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/05/2012] [Indexed: 01/24/2023] Open
Abstract
Down syndrome (DS) leads to complex phenotypes and is the main genetic cause of birth defects and heart diseases. The Ts65Dn DS mouse model is trisomic for the distal part of mouse chromosome 16 and displays similar features with post-natal lethality and cardiovascular defects. In order to better understand these defects, we defined electrocardiogram (ECG) with a precordial set-up, and we found conduction defects and modifications in wave shape, amplitudes, and durations in Ts65Dn mice. By using a genetic approach consisting of crossing Ts65Dn mice with Ms5Yah mice monosomic for the App-Runx1 genetic interval, we showed that the Ts65Dn viability and ECG were improved by this reduction of gene copy number. Whole-genome expression studies confirmed gene dosage effect in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah hearts and showed an overall perturbation of pathways connected to post-natal lethality (Coq7, Dyrk1a, F5, Gabpa, Hmgn1, Pde10a, Morc3, Slc5a3, and Vwf) and heart function (Tfb1m, Adam19, Slc8a1/Ncx1, and Rcan1). In addition cardiac connexins (Cx40, Cx43) and sodium channel sub-units (Scn5a, Scn1b, Scn10a) were found down-regulated in Ts65Dn atria with additional down-regulation of Cx40 in Ts65Dn ventricles and were likely contributing to conduction defects. All these data pinpoint new cardiac phenotypes in the Ts65Dn, mimicking aspects of human DS features and pathways altered in the mouse model. In addition they highlight the role of the App-Runx1 interval, including Sod1 and Tiam1, in the induction of post-natal lethality and of the cardiac conduction defects in Ts65Dn. These results might lead to new therapeutic strategies to improve the care of DS people.
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Affiliation(s)
- Matthieu Raveau
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Jacques M. Lignon
- Immunologie et Embryologie Moléculaire, CNRS Université d'Orléans, UMR6218, Orléans, France
| | - Valérie Nalesso
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Arnaud Duchon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Yoram Groner
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Andrew J. Sharp
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Doulaye Dembele
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Véronique Brault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
- Transgénèse et Archivage d'Animaux Modèles, CNRS, UPS44, Orléans, France
- Institut Clinique de la Souris, Illkirch, France
- * E-mail:
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36
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Risebro CA, Petchey LK, Smart N, Gomes J, Clark J, Vieira JM, Yanni J, Dobrzynski H, Davidson S, Zuberi Z, Tinker A, Shui B, Tallini YI, Kotlikoff MI, Miquerol L, Schwartz RJ, Riley PR. Epistatic rescue of Nkx2.5 adult cardiac conduction disease phenotypes by prospero-related homeobox protein 1 and HDAC3. Circ Res 2012; 111:e19-31. [PMID: 22647876 DOI: 10.1161/circresaha.111.260695] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Nkx2.5 is one of the most widely studied cardiac-specific transcription factors, conserved from flies to man, with multiple essential roles in both the developing and adult heart. Specific dominant mutations in NKX2.5 have been identified in adult congenital heart disease patients presenting with conduction system anomalies and recent genome-wide association studies implicate the NKX2.5 locus, as causative for lethal arrhythmias ("sudden cardiac death") that occur at a frequency in the population of 1 in 1000 per annum worldwide. Haploinsufficiency for Nkx2.5 in the mouse phenocopies human conduction disease pathology yet the phenotypes, described in both mouse and man, are highly pleiotropic, implicit of unknown modifiers and/or factors acting in epistasis with Nkx2.5/NKX2.5. OBJECTIVE To identify bone fide upstream genetic modifier(s) of Nkx2.5/NKX2.5 function and to determine epistatic effects relevant to the manifestation of NKX2.5-dependent adult congenital heart disease. METHODS AND RESULTS A study of cardiac function in prospero-related homeobox protein 1 (Prox1) heterozygous mice, using pressure-volume loop and micromannometry, revealed rescue of hemodynamic parameters in Nkx2.5(Cre/+); Prox1(loxP/+) animals versus Nkx2.5(Cre/+) controls. Anatomic studies, on a Cx40(EGFP) background, revealed Cre-mediated knock-down of Prox1 restored the anatomy of the atrioventricular node and His-Purkinje network both of which were severely hypoplastic in Nkx2.5(Cre/+) littermates. Steady state surface electrocardiography recordings and high-speed multiphoton imaging, to assess Ca(2+) handling, revealed atrioventricular conduction and excitation-contraction were also normalized by Prox1 haploinsufficiency, as was expression of conduction genes thought to act downstream of Nkx2.5. Chromatin immunoprecipitation on adult hearts, in combination with both gain and loss-of-function reporter assays in vitro, revealed that Prox1 recruits the corepressor HDAC3 to directly repress Nkx2.5 via a proximal upstream enhancer as a mechanism for regulating Nkx2.5 function in adult cardiac conduction. CONCLUSIONS Here we identify Prox1 as a direct upstream modifier of Nkx2.5 in the maintenance of the adult conduction system and rescue of Nkx2.5 conduction disease phenotypes. This study is the first example of rescue of Nkx2.5 function and establishes a model for ensuring electrophysiological function within the adult heart alongside insight into a novel Prox1-HDAC3-Nkx2.5 signaling pathway for therapeutic targeting in conduction disease.
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Lujan HL, Janbaih H, Feng HZ, Jin JP, DiCarlo SE. Myocardial ischemia, reperfusion, and infarction in chronically instrumented, intact, conscious, and unrestrained mice. Am J Physiol Regul Integr Comp Physiol 2012; 302:R1384-400. [PMID: 22538514 DOI: 10.1152/ajpregu.00095.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the United States alone, the National Heart, Lung, and Blood Institute (NHLBI) has invested several hundred million dollars in pursuit of myocardial infarct-sparing therapies. However, due largely to methodological limitations, this investment has not produced any notable clinical application or cardioprotective therapy. Among the major methodological limitations is the reliance on animal models that do not mimic the clinical situation. In this context, the limited use of conscious animal models is of major concern. In fact, whenever possible, studies of cardiovascular physiology and pathophysiology should be conducted in conscious, complex models to avoid the complications associated with the use of anesthesia and surgical trauma. The mouse has significant advantages over other experimental models for the investigation of infarct-sparing therapies. The mouse is inexpensive, has a high throughput, and presents the ability of one to create genetically modified models. However, successful infarct-sparing therapies in anesthetized mice or isolated mouse hearts may not be successful in more complex models, including conscious mice. Accordingly, a conscious mouse model of myocardial ischemia and reperfusion has the potential to be of major importance for advancing the concepts and methods that drive the development of infarct-sparing therapies. Therefore, we describe, for the first time, the use of an intact, conscious, and unrestrained mouse model of myocardial ischemia-reperfusion and infarction. The conscious mouse model permits occlusion and reperfusion of the left anterior descending coronary artery in an intact, complex model free of the confounding influences of anesthetics and surgical trauma. This methodology may be adopted for advancing the concepts and ideas that drive cardiovascular research.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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Oyamada M, Takebe K, Oyamada Y. Regulation of connexin expression by transcription factors and epigenetic mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:118-33. [PMID: 22244842 DOI: 10.1016/j.bbamem.2011.12.031] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 12/17/2011] [Accepted: 12/27/2011] [Indexed: 01/24/2023]
Abstract
Gap junctions are specialized cell-cell junctions that directly link the cytoplasm of neighboring cells. They mediate the direct transfer of metabolites and ions from one cell to another. Discoveries of human genetic disorders due to mutations in gap junction protein (connexin [Cx]) genes and experimental data on connexin knockout mice provide direct evidence that gap junctional intercellular communication is essential for tissue functions and organ development, and that its dysfunction causes diseases. Connexin-related signaling also involves extracellular signaling (hemichannels) and non-channel intracellular signaling. Thus far, 21 human genes and 20 mouse genes for connexins have been identified. Each connexin shows tissue- or cell-type-specific expression, and most organs and many cell types express more than one connexin. Connexin expression can be regulated at many of the steps in the pathway from DNA to RNA to protein. In recent years, it has become clear that epigenetic processes are also essentially involved in connexin gene expression. In this review, we summarize recent knowledge on regulation of connexin expression by transcription factors and epigenetic mechanisms including histone modifications, DNA methylation, and microRNA. This article is part of a Special Issue entitled: The communicating junctions, roles and dysfunctions.
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Affiliation(s)
- Masahito Oyamada
- Department of Food Science and Human Nutrition, Fuji Women's University, Ishikarishi, Japan.
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Costa MW, Lee S, Furtado MB, Xin L, Sparrow DB, Martinez CG, Dunwoodie SL, Kurtenbach E, Mohun T, Rosenthal N, Harvey RP. Complex SUMO-1 regulation of cardiac transcription factor Nkx2-5. PLoS One 2011; 6:e24812. [PMID: 21931855 PMCID: PMC3171482 DOI: 10.1371/journal.pone.0024812] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 08/22/2011] [Indexed: 01/04/2023] Open
Abstract
Reversible post-translational protein modifications such as SUMOylation add complexity to cardiac transcriptional regulation. The homeodomain transcription factor Nkx2-5/Csx is essential for heart specification and morphogenesis. It has been previously suggested that SUMOylation of lysine 51 (K51) of Nkx2-5 is essential for its DNA binding and transcriptional activation. Here, we confirm that SUMOylation strongly enhances Nkx2-5 transcriptional activity and that residue K51 of Nkx2-5 is a SUMOylation target. However, in a range of cultured cell lines we find that a point mutation of K51 to arginine (K51R) does not affect Nkx2-5 activity or DNA binding, suggesting the existence of additional Nkx2-5 SUMOylated residues. Using biochemical assays, we demonstrate that Nkx2-5 is SUMOylated on at least one additional site, and this is the predominant site in cardiac cells. The second site is either non-canonical or a "shifting" site, as mutation of predicted consensus sites and indeed every individual lysine in the context of the K51R mutation failed to impair Nkx2-5 transcriptional synergism with SUMO, or its nuclear localization and DNA binding. We also observe SUMOylation of Nkx2-5 cofactors, which may be critical to Nkx2-5 regulation. Our data reveal highly complex regulatory mechanisms driven by SUMOylation to modulate Nkx2-5 activity.
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Affiliation(s)
- Mauro W Costa
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
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Kim EY, Chen L, Ma Y, Yu W, Chang J, Moskowitz IP, Wang J. Expression of sumoylation deficient Nkx2.5 mutant in Nkx2.5 haploinsufficient mice leads to congenital heart defects. PLoS One 2011; 6:e20803. [PMID: 21677783 PMCID: PMC3108998 DOI: 10.1371/journal.pone.0020803] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 05/12/2011] [Indexed: 12/16/2022] Open
Abstract
Nkx2.5 is a cardiac specific homeobox gene critical for normal heart development. We previously identified Nkx2.5 as a target of sumoylation, a posttranslational modification implicated in a variety of cellular activities. Sumoylation enhanced Nkx2.5 activity via covalent attachment to the lysine residue 51, the primary SUMO acceptor site. However, how sumoylation regulates the activity of Nkx2.5 in vivo remains unknown. We generated transgenic mice overexpressing sumoylation deficient mutant K51R (conversion of lysine 51 to arginine) specifically in mouse hearts under the control of cardiac α-myosin heavy chain (α-MHC) promoter (K51R-Tg). Expression of the Nkx2.5 mutant transgene in the wild type murine hearts did not result in any overt cardiac phenotype. However, in the presence of Nkx2.5 haploinsufficiency, cardiomyocyte-specific expression of the Nkx2.5 K51R mutant led to congenital heart diseases (CHDs), accompanied with decreased cardiomyocyte proliferation. Also, a number of human CHDs-associated Nkx2.5 mutants exhibited aberrant sumoylation. Our work demonstrates that altered sumoylation status may underlie the development of human CHDs associated with Nkx2.5 mutants.
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Affiliation(s)
- Eun Young Kim
- Program in Genes and Development, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Li Chen
- Department of Basic Research Laboratories, Texas Heart Institute, Houston, Texas, United States of America
| | - Yanlin Ma
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, United States of America
| | - Wei Yu
- Department of Biochemistry and Molecular Biology, University of Houston, Houston, Texas, United States of America
| | - Jiang Chang
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, United States of America
| | - Ivan P. Moskowitz
- Departments of Pediatrics and Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jun Wang
- Department of Basic Research Laboratories, Texas Heart Institute, Houston, Texas, United States of America
- * E-mail:
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Affiliation(s)
- David S Park
- Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, NY 10016, USA
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Mueller EE, Momen A, Massé S, Zhou YQ, Liu J, Backx PH, Henkelman RM, Nanthakumar K, Stewart DJ, Husain M. Electrical remodelling precedes heart failure in an endothelin-1-induced model of cardiomyopathy. Cardiovasc Res 2011; 89:623-33. [PMID: 21062919 DOI: 10.1093/cvr/cvq351] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
AIMS Binary transgenic (BT) mice with doxycycline (DOX)-suppressible cardiac-specific overexpression of endothelin-1 (ET-1) exhibit progressive heart failure (HF), QRS prolongation, and death following DOX withdrawal. However, the molecular basis and reversibility of the electrophysiological abnormalities in this model were not known. Here, we assess the mechanisms underlying ET-1-mediated electrical remodelling, and its role in HF. METHODS AND RESULTS BT vs. non-BT littermate controls were withdrawn from DOX and serially studied with ultrasound biomicroscopy, octapolar catheters, multielectrode epicardial mapping, histopathology, western blot, immunohistochemistry, and qRT-PCR. Abnormalities in ventricular activation and -dV/dt were detected as early as 4 weeks after transgene activation, when the structure and function of the heart remained unaffected. By 8 weeks of ET-1 overexpression, biventricular systolic and diastolic dysfunction, myocardial fibrosis, and cardiomyocyte hypertrophy were observed. Intracardiac and epicardial electrograms revealed prolonged conduction and ventricular activation, reduced -dV/dt, and abnormal atrioventricular nodal function. Within 4 weeks of ET-1 induction, connexin 40 (Cx40) protein and Cx43 mRNA, protein, and phosphorylation levels were reduced by 36, 64, 93, and 69%, respectively; Na(v)1.5 mRNA and protein levels were reduced by 30 and 50%, respectively, as was Na(+) channel conductance. Importantly, the associated electrophysiological abnormalities at this time point were reversible upon suppression of ET-1 overexpression and completely prevented the development of structural and functional remodelling. CONCLUSION ET-1-mediated electrical remodelling correlates with reduced Cx40, Cx43, and Na(v)1.5 expression and decreased Na(+) channel conductance and precedes HF. The sequence and reversibility of this phenotype suggest that a primary abnormality in electrical remodelling may contribute to the pathogenesis of HF.
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Affiliation(s)
- Erin E Mueller
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Terada R, Warren S, Lu JT, Chien KR, Wessels A, Kasahara H. Ablation of Nkx2-5 at mid-embryonic stage results in premature lethality and cardiac malformation. Cardiovasc Res 2011; 91:289-99. [PMID: 21285290 DOI: 10.1093/cvr/cvr037] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIMS Human congenital heart disease linked to mutations in the homeobox transcription factor, NKX2-5, is characterized by cardiac anomalies, including atrial and ventricular septal defects as well as conduction and occasional defects in contractility. In the mouse, homozygous germline deletion of Nkx2-5 gene results in death around E10.5. It is, however, not established whether Nkx2-5 is necessary for cardiac development beyond this embryonic stage. Because human NKX2-5 mutations are related to septum secundum type atrial septal defects (ASD), we hypothesized that Nkx2-5 deficiency during the processes of septum secundum formation may cause cardiac anomalies; thus, we analysed mice with tamoxifen-inducible Nkx2-5 ablation beginning at E12.5 when the septum secundum starts to develop. METHODS AND RESULTS Using tamoxifen-inducible Nkx2-5 gene-targeted mice, this study demonstrates that Nkx2-5 ablation beginning at E12.5 results in embryonic death by E17.5. Analysis of mutant embryos at E16.5 shows arrhythmias, contraction defects, and cardiac malformations, including ASD. Quantitative measurements using serial section histology and three-dimensional reconstruction demonstrate growth retardation of the septum secundum and enlarged foramen ovale in Nkx2-5-ablated embryos. Functional cardiac defects may be attributed to abnormal expression of transcripts critical for conduction and contraction, including cardiac voltage-gated Na(+) channel pore-forming α-subunit (Na(v)1.5-α), gap junction protein connexin40, cardiac myosin light chain kinase, and sarcolipin within 4 days after tamoxifen injection. CONCLUSION Nkx2-5 is necessary for survival after the mid-embryonic stage for cardiac function and formation by regulating the expression of its downstream target genes.
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Affiliation(s)
- Ryota Terada
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610-0274, USA
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Development of electrocardiogram intervals during growth of FVB/N neonate mice. BMC PHYSIOLOGY 2010; 10:16. [PMID: 20735846 PMCID: PMC2936334 DOI: 10.1186/1472-6793-10-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 08/24/2010] [Indexed: 12/13/2022]
Abstract
Background Electrocardiography remains the best diagnostic tool and therapeutic biomarker for a spectrum of pediatric diseases involving cardiac or autonomic nervous system defects. As genetic links to these disorders are established and transgenic mouse models produced in efforts to understand and treat them, there is a surprising lack of information on electrocardiograms (ECGs) and ECG abnormalities in neonate mice. This is likely due to the trauma and anaesthesia required of many legacy approaches to ECG recording in mice, exacerbated by the fragility of many mutant neonates. Here, we use a non-invasive system to characterize development of the heart rate and electrocardiogram throughout the growth of conscious neonate FVB/N mice. Results We examine ECG waveforms as early as two days after birth. At this point males and females demonstrate comparable heart rates that are 50% lower than adult mice. Neonatal mice exhibit very low heart rate variability. Within 12 days of birth PR, QRS and QTc interval durations are near adult values while heart rate continues to increase until weaning. Upon weaning FVB/N females quickly develop slower heart rates than males, though PR intervals are comparable between sexes until a later age. This suggests separate developmental events may contribute to these gender differences in electrocardiography. Conclusions We provide insight with a new level of detail to the natural course of heart rate establishment in neonate mice. ECG can now be conveniently and repeatedly used in neonatal mice. This should serve to be of broad utility, facilitating further investigations into development of a diverse group of diseases and therapeutics in preclinical mouse studies.
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Alvarez-Saavedra M, Carrasco L, Sura-Trueba S, Demarchi Aiello V, Walz K, Neto JX, Young JI. Elevated expression of MeCP2 in cardiac and skeletal tissues is detrimental for normal development. Hum Mol Genet 2010; 19:2177-90. [PMID: 20203171 DOI: 10.1093/hmg/ddq096] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
MeCP2 plays a critical role in interpreting epigenetic signatures that command chromatin conformation and regulation of gene transcription. In spite of MeCP2's ubiquitous expression, its functions have always been considered in the context of brain physiology. In this study, we demonstrate that alterations of the normal pattern of expression of MeCP2 in cardiac and skeletal tissues are detrimental for normal development. Overexpression of MeCP2 in the mouse heart leads to embryonic lethality with cardiac septum hypertrophy and dysregulated expression of MeCP2 in skeletal tissue produces severe malformations. We further show that MeCP2's expression in the heart is developmentally regulated; further suggesting that it plays a key role in regulating transcriptional programs in non-neural tissues.
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Briggs LE, Takeda M, Cuadra AE, Wakimoto H, Marks MH, Walker AJ, Seki T, Oh SP, Lu JT, Sumners C, Raizada MK, Horikoshi N, Weinberg EO, Yasui K, Ikeda Y, Chien KR, Kasahara H. Perinatal loss of Nkx2-5 results in rapid conduction and contraction defects. Circ Res 2008; 103:580-90. [PMID: 18689573 DOI: 10.1161/circresaha.108.171835] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Homeobox transcription factor Nkx2-5, highly expressed in heart, is a critical factor during early embryonic cardiac development. In this study, using tamoxifen-inducible Nkx2-5 knockout mice, we demonstrate the role of Nkx2-5 in conduction and contraction in neonates within 4 days after perinatal tamoxifen injection. Conduction defect was accompanied by reduction in ventricular expression of the cardiac voltage-gated Na+ channel pore-forming alpha-subunit (Na(v)1.5-alpha), the largest ion channel in the heart responsive for rapid depolarization of the action potential, which leads to increased intracellular Ca2+ for contraction (conduction-contraction coupling). In addition, expression of ryanodine receptor 2, through which Ca2+ is released from sarcoplasmic reticulum, was substantially reduced in Nkx2-5 knockout mice. These results indicate that Nkx2-5 function is critical not only during cardiac development but also in perinatal hearts, by regulating expression of several important gene products involved in conduction and contraction.
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Affiliation(s)
- Laura E Briggs
- University of Florida College of Medicine, 1600 SW Archer Rd, M-540, Gainesville, FL 32610-0274, USA
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MURC, a muscle-restricted coiled-coil protein that modulates the Rho/ROCK pathway, induces cardiac dysfunction and conduction disturbance. Mol Cell Biol 2008; 28:3424-36. [PMID: 18332105 DOI: 10.1128/mcb.02186-07] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We identified a novel muscle-restricted putative coiled-coil protein, MURC, which is evolutionarily conserved from frog to human. MURC was localized to the cytoplasm with accumulation in the Z-line of the sarcomere in the murine adult heart. MURC mRNA expression in the heart increased during the developmental process from the embryonic stage to adulthood. In response to pressure overload, MURC mRNA expression increased in the hypertrophied heart. Using the yeast two-hybrid system, we identified the serum deprivation response (SDPR) protein, a phosphatidylserine-binding protein, as a MURC-binding protein. MURC induced activation of the RhoA/ROCK pathway, which modulated serum response factor-mediated atrial natriuretic peptide (ANP) expression and myofibrillar organization. SDPR augmented MURC-induced transactivation of the ANP promoter in cardiomyocytes, and RNA interference of SDPR attenuated the action of MURC on the ANP promoter. Transgenic mice expressing cardiac-specific MURC (Tg-MURC) exhibited cardiac contractile dysfunction and atrioventricular (AV) conduction disturbances with atrial chamber enlargement, reduced thickness of the ventricular wall, and interstitial fibrosis. Spontaneous episodes of atrial fibrillation and AV block were observed in Tg-MURC mice. These findings indicate that MURC modulates RhoA signaling and that MURC plays an important role in the development of cardiac dysfunction and conduction disturbance with increased vulnerability to atrial arrhythmias.
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Chan JY, Takeda M, Briggs LE, Graham ML, Lu JT, Horikoshi N, Weinberg EO, Aoki H, Sato N, Chien KR, Kasahara H. Identification of cardiac-specific myosin light chain kinase. Circ Res 2008; 102:571-80. [PMID: 18202317 DOI: 10.1161/circresaha.107.161687] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two myosin light chain (MLC) kinase (MLCK) proteins, smooth muscle (encoded by mylk1 gene) and skeletal (encoded by mylk2 gene) MLCK, have been shown to be expressed in mammals. Even though phosphorylation of its putative substrate, MLC2, is recognized as a key regulator of cardiac contraction, a MLCK that is preferentially expressed in cardiac muscle has not yet been identified. In this study, we characterized a new kinase encoded by a gene homologous to mylk1 and -2, named cardiac MLCK, which is specifically expressed in the heart in both atrium and ventricle. In fact, expression of cardiac MLCK is highly regulated by the cardiac homeobox protein Nkx2-5 in neonatal cardiomyocytes. The overall structure of cardiac MLCK protein is conserved with skeletal and smooth muscle MLCK; however, the amino terminus is quite unique, without significant homology to other known proteins, and its catalytic activity does not appear to be regulated by Ca(2+)/calmodulin in vitro. Cardiac MLCK is phosphorylated and the level of phosphorylation is increased by phenylephrine stimulation accompanied by increased level of MLC2v phosphorylation. Both overexpression and knockdown of cardiac MLCK in cultured cardiomyocytes revealed that cardiac MLCK is likely a new regulator of MLC2 phosphorylation, sarcomere organization, and cardiomyocyte contraction.
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Affiliation(s)
- Jason Y Chan
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1600 SW Archer Rd, Gainesville, FL 32610-0274, USA
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Yadava RS, Frenzel-McCardell CD, Yu Q, Srinivasan V, Tucker AL, Puymirat J, Thornton CA, Prall OW, Harvey RP, Mahadevan MS. RNA toxicity in myotonic muscular dystrophy induces NKX2-5 expression. Nat Genet 2008; 40:61-8. [PMID: 18084293 PMCID: PMC2909759 DOI: 10.1038/ng.2007.28] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Accepted: 09/26/2007] [Indexed: 11/10/2022]
Abstract
Myotonic muscular dystrophy (DM1) is the most common inherited neuromuscular disorder in adults and is considered the first example of a disease caused by RNA toxicity. Using a reversible transgenic mouse model of RNA toxicity in DM1, we provide evidence that DM1 is associated with induced NKX2-5 expression. Transgene expression resulted in cardiac conduction defects, increased expression of the cardiac-specific transcription factor NKX2-5 and profound disturbances in connexin 40 and connexin 43. Notably, overexpression of the DMPK 3' UTR mRNA in mouse skeletal muscle also induced transcriptional activation of Nkx2-5 and its targets. In human muscles, these changes were specific to DM1 and were not present in other muscular dystrophies. The effects on NKX2-5 and its downstream targets were reversed by silencing toxic RNA expression. Furthermore, using Nkx2-5+/- mice, we show that NKX2-5 is the first genetic modifier of DM1-associated RNA toxicity in the heart.
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Affiliation(s)
- Ramesh S Yadava
- Department of Pathology, University of Virginia, Charlottesville, Virginia 22908, USA
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Bartlett HL, Sutherland L, Kolker SJ, Welp C, Tajchman U, Desmarais V, Weeks DL. Transient early embryonic expression of Nkx2-5 mutations linked to congenital heart defects in human causes heart defects in Xenopus laevis. Dev Dyn 2007; 236:2475-84. [PMID: 17685485 PMCID: PMC2078326 DOI: 10.1002/dvdy.21244] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Nkx2-5 is a homeobox containing transcription factor that is conserved and expressed in organisms that form hearts. Fruit flies lacking the gene (tinman) fail to form a dorsal vessel, mice that are homozygous null for Nkx2-5 form small, deformed hearts, and several human cardiac defects have been linked to dominant mutations in the Nkx2-5 gene. The Xenopus homologs (XNkx2-5) of two truncated forms of Nkx2-5 that have been identified in humans with congenital heart defects were used in the studies reported here. mRNAs encoding these mutations were injected into single cell Xenopus embryos, and heart development was monitored. Our results indicate that the introduction of truncated XNkx2-5 variants leads to three principle developmental defects. The atrial septum and the valve of the atrioventricular canal were both abnormal. In addition, video microscopic timing of heart contraction indicated that embryos injected with either mutant form of XNkx2-5 have conduction defects.
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Affiliation(s)
| | - Lillian Sutherland
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Sandra J. Kolker
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Chelsea Welp
- Department of Pediatrics, University of Iowa, Iowa City, Iowa
| | | | - Vera Desmarais
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Daniel L. Weeks
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
- *Correspondence to: Daniel L. Weeks, Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, IA 52242-1109. E-mail:
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