1
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Lahiri SK, Jin F, Zhou Y, Quick AP, Kramm CF, Wang MC, Wehrens XH. Altered myocardial lipid regulation in junctophilin-2-associated familial cardiomyopathies. Life Sci Alliance 2024; 7:e202302330. [PMID: 38438248 PMCID: PMC10912815 DOI: 10.26508/lsa.202302330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024] Open
Abstract
Myocardial lipid metabolism is critical to normal heart function, whereas altered lipid regulation has been linked to cardiac diseases including cardiomyopathies. Genetic variants in the JPH2 gene can cause hypertrophic cardiomyopathy (HCM) and, in some cases, dilated cardiomyopathy (DCM). In this study, we tested the hypothesis that JPH2 variants identified in patients with HCM and DCM, respectively, cause distinct alterations in myocardial lipid profiles. Echocardiography revealed clinically significant cardiac dysfunction in both knock-in mouse models of cardiomyopathy. Unbiased myocardial lipidomic analysis demonstrated significantly reduced levels of total unsaturated fatty acids, ceramides, and various phospholipids in both mice with HCM and DCM, suggesting a common metabolic alteration in both models. On the contrary, significantly increased di- and triglycerides, and decreased co-enzyme were only found in mice with HCM. Moreover, mice with DCM uniquely exhibited elevated levels of cholesterol ester. Further in-depth analysis revealed significantly altered metabolites from all the lipid classes with either similar or opposing trends in JPH2 mutant mice with HCM or DCM. Together, these studies revealed, for the first time, unique alterations in the cardiac lipid composition-including distinct increases in neutral lipids and decreases in polar membrane lipids-in mice with HCM and DCM were caused by distinct JPH2 variants. These studies may aid the development of novel biomarkers or therapeutics for these inherited disorders.
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Affiliation(s)
- Satadru K Lahiri
- https://ror.org/02pttbw34 Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Feng Jin
- https://ror.org/02pttbw34 Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Yue Zhou
- https://ror.org/02pttbw34 Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
| | - Ann P Quick
- https://ror.org/02pttbw34 Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Carlos F Kramm
- https://ror.org/02pttbw34 Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Meng C Wang
- https://ror.org/02pttbw34 Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, USA
| | - Xander Ht Wehrens
- https://ror.org/02pttbw34 Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Medicine, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- https://ror.org/02pttbw34 Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA
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2
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Hall DD, Takeshima H, Song LS. Structure, Function, and Regulation of the Junctophilin Family. Annu Rev Physiol 2024; 86:123-147. [PMID: 37931168 PMCID: PMC10922073 DOI: 10.1146/annurev-physiol-042022-014926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
In both excitable and nonexcitable cells, diverse physiological processes are linked to different calcium microdomains within nanoscale junctions that form between the plasma membrane and endo-sarcoplasmic reticula. It is now appreciated that the junctophilin protein family is responsible for establishing, maintaining, and modulating the structure and function of these junctions. We review foundational findings from more than two decades of research that have uncovered how junctophilin-organized ultrastructural domains regulate evolutionarily conserved biological processes. We discuss what is known about the junctophilin family of proteins. Our goal is to summarize the current knowledge of junctophilin domain structure, function, and regulation and to highlight emerging avenues of research that help our understanding of the transcriptional, translational, and post-translational regulation of this gene family and its roles in health and during disease.
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Affiliation(s)
- Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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3
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Mariani MV, Pierucci N, Fanisio F, Laviola D, Silvetti G, Piro A, La Fazia VM, Chimenti C, Rebecchi M, Drago F, Miraldi F, Natale A, Vizza CD, Lavalle C. Inherited Arrhythmias in the Pediatric Population: An Updated Overview. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:94. [PMID: 38256355 PMCID: PMC10819657 DOI: 10.3390/medicina60010094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/17/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024]
Abstract
Pediatric cardiomyopathies (CMs) and electrical diseases constitute a heterogeneous spectrum of disorders distinguished by structural and electrical abnormalities in the heart muscle, attributed to a genetic variant. They rank among the main causes of morbidity and mortality in the pediatric population, with an annual incidence of 1.1-1.5 per 100,000 in children under the age of 18. The most common conditions are dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Despite great enthusiasm for research in this field, studies in this population are still limited, and the management and treatment often follow adult recommendations, which have significantly more data on treatment benefits. Although adult and pediatric cardiac diseases share similar morphological and clinical manifestations, their outcomes significantly differ. This review summarizes the latest evidence on genetics, clinical characteristics, management, and updated outcomes of primary pediatric CMs and electrical diseases, including DCM, HCM, arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), long QT syndrome (LQTS), and short QT syndrome (SQTS).
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Affiliation(s)
- Marco Valerio Mariani
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Nicola Pierucci
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Francesca Fanisio
- Division of Cardiology, Policlinico Casilino, 00169 Rome, Italy; (F.F.); (M.R.)
| | - Domenico Laviola
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Giacomo Silvetti
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Agostino Piro
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Vincenzo Mirco La Fazia
- Department of Electrophysiology, St. David’s Medical Center, Texas Cardiac Arrhythmia Institute, Austin, TX 78705, USA; (V.M.L.F.); (A.N.)
| | - Cristina Chimenti
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Marco Rebecchi
- Division of Cardiology, Policlinico Casilino, 00169 Rome, Italy; (F.F.); (M.R.)
| | - Fabrizio Drago
- Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children’s Hospital and Research Institute, 00165 Rome, Italy;
| | - Fabio Miraldi
- Cardio Thoracic-Vascular and Organ Transplantation Surgery Department, Policlinico Umberto I Hospital, 00161 Rome, Italy;
| | - Andrea Natale
- Department of Electrophysiology, St. David’s Medical Center, Texas Cardiac Arrhythmia Institute, Austin, TX 78705, USA; (V.M.L.F.); (A.N.)
| | - Carmine Dario Vizza
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
| | - Carlo Lavalle
- Department of Cardiovascular, Respiratory, Nephrological, Aenesthesiological and Geriatric Sciences, “Sapienza” University of Rome, 00161 Rome, Italy; (N.P.); (D.L.); (G.S.); (A.P.); (C.C.); (C.D.V.); (C.L.)
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4
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Lipov A, Jurgens SJ, Mazzarotto F, Allouba M, Pirruccello JP, Aguib Y, Gennarelli M, Yacoub MH, Ellinor PT, Bezzina CR, Walsh R. Exploring the complex spectrum of dominance and recessiveness in genetic cardiomyopathies. NATURE CARDIOVASCULAR RESEARCH 2023; 2:1078-1094. [PMID: 38666070 PMCID: PMC11041721 DOI: 10.1038/s44161-023-00346-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/07/2023] [Indexed: 04/28/2024]
Abstract
Discrete categorization of Mendelian disease genes into dominant and recessive models often oversimplifies their underlying genetic architecture. Cardiomyopathies (CMs) are genetic diseases with complex etiologies for which an increasing number of recessive associations have recently been proposed. Here, we comprehensively analyze all published evidence pertaining to biallelic variation associated with CM phenotypes to identify high-confidence recessive genes and explore the spectrum of monoallelic and biallelic variant effects in established recessive and dominant disease genes. We classify 18 genes with robust recessive association with CMs, largely characterized by dilated phenotypes, early disease onset and severe outcomes. Several of these genes have monoallelic association with disease outcomes and cardiac traits in the UK Biobank, including LMOD2 and ALPK3 with dilated and hypertrophic CM, respectively. Our data provide insights into the complex spectrum of dominance and recessiveness in genetic heart disease and demonstrate how such approaches enable the discovery of unexplored genetic associations.
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Affiliation(s)
- Alex Lipov
- Department of Experimental Cardiology, Heart Centre, Amsterdam UMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Sean J. Jurgens
- Department of Experimental Cardiology, Heart Centre, Amsterdam UMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA USA
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA
| | - Francesco Mazzarotto
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Mona Allouba
- National Heart and Lung Institute, Imperial College London, London, UK
- Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
| | - James P. Pirruccello
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA USA
- Division of Cardiology, University of California, San Francisco, San Francisco, CA USA
| | - Yasmine Aguib
- National Heart and Lung Institute, Imperial College London, London, UK
- Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
| | - Massimo Gennarelli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
- Genetics Unit, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Magdi H. Yacoub
- National Heart and Lung Institute, Imperial College London, London, UK
- Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
- Harefield Heart Science Centre, Uxbridge, UK
| | - Patrick T. Ellinor
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA USA
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA
- Demoulas Center for Cardiac Arrhythmias, Massachusetts General Hospital, Boston, MA USA
| | - Connie R. Bezzina
- Department of Experimental Cardiology, Heart Centre, Amsterdam UMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart, Amsterdam, the Netherlands
| | - Roddy Walsh
- Department of Experimental Cardiology, Heart Centre, Amsterdam UMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
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5
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Maurer C, Boleti O, Najarzadeh Torbati P, Norouzi F, Fowler ANR, Minaee S, Salih KH, Taherpour M, Birjandi H, Alizadeh B, Salih AF, Bijari M, Houlden H, Pittman AM, Maroofian R, Almashham YH, Karimiani EG, Kaski JP, Faqeih EA, Vakilian F, Jamshidi Y. Genetic Insights from Consanguineous Cardiomyopathy Families. Genes (Basel) 2023; 14:182. [PMID: 36672924 PMCID: PMC9858866 DOI: 10.3390/genes14010182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 01/13/2023] Open
Abstract
Inherited cardiomyopathies are a prevalent cause of heart failure and sudden cardiac death. Both hypertrophic (HCM) and dilated cardiomyopathy (DCM) are genetically heterogeneous and typically present with an autosomal dominant mode of transmission. Whole exome sequencing and autozygosity mapping was carried out in eight un-related probands from consanguineous Middle Eastern families presenting with HCM/DCM followed by bioinformatic and co-segregation analysis to predict the potential pathogenicity of candidate variants. We identified homozygous missense variants in TNNI3K, DSP, and RBCK1 linked with a dilated phenotype, in NRAP linked with a mixed phenotype of dilated/hypertrophic, and in KLHL24 linked with a mixed phenotype of dilated/hypertrophic and non-compaction features. Co-segregation analysis in family members confirmed autosomal recessive inheritance presenting in early childhood/early adulthood. Our findings add to the mutational spectrum of recessive cardiomyopathies, supporting inclusion of KLHL24, NRAP and RBCK1 as disease-causing genes. We also provide evidence for novel (recessive) modes of inheritance of a well-established gene TNNI3K and expand our knowledge of the clinical heterogeneity of cardiomyopathies. A greater understanding of the genetic causes of recessive cardiomyopathies has major implications for diagnosis and screening, particularly in underrepresented populations, such as those of the Middle East.
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Affiliation(s)
- Constance Maurer
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Olga Boleti
- Centre for Paediatric Inherited and Rare Cardiovascular Disease, University College London and Great Ormond Street Hospital, London WC1N 1DZ, UK
| | | | - Farzaneh Norouzi
- Department of Cardiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
| | - Anna Nicole Rebekah Fowler
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Shima Minaee
- Department of Cardiovascular Diseases, Razavi Hospital, Mashhad 9177948954, Iran
| | - Khalid Hama Salih
- Department of Pediatrics, College of Medicine, Sulaimani University, Sulaymaniyah 46001, Iraq
| | - Mehdi Taherpour
- Department of Cardiovascular Diseases, Razavi Hospital, Mashhad 9177948954, Iran
| | - Hassan Birjandi
- Division of Congenital and Pediatric Cardiology, Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
| | - Behzad Alizadeh
- Division of Congenital and Pediatric Cardiology, Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
| | - Aso Faeq Salih
- Department of Pediatrics, College of Medicine, Sulaimani University, Sulaymaniyah 46001, Iraq
| | - Moniba Bijari
- Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Alan Michael Pittman
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Reza Maroofian
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Yahya H. Almashham
- Pediatric Cardiology, King Salman Heart Center, King Fahad Medical City, Riyadh 12231, Saudi Arabia
| | - Ehsan Ghayoor Karimiani
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
- Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad 009851, Iran
| | - Juan Pablo Kaski
- Centre for Paediatric Inherited and Rare Cardiovascular Disease, University College London and Great Ormond Street Hospital, London WC1N 1DZ, UK
| | - Eissa Ali Faqeih
- Section of Medical Genetics, Children’s Specialist Hospital, King Fahad Medical City, Riyadh 12231, Saudi Arabia
| | - Farveh Vakilian
- Department of Cardiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
| | - Yalda Jamshidi
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
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6
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Patel V, Chahal CAA. Editorial commentary: Genomic and precision medicine provides deeper insights into the genetic basis of diverse JPH2-mediated phenotypes. Trends Cardiovasc Med 2023; 33:11-12. [PMID: 34965474 DOI: 10.1016/j.tcm.2021.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 02/01/2023]
Affiliation(s)
- Viraj Patel
- North West Thames Regional Genetics Service, St Mark's and Northwick Park Hospitals, London, UK
| | - C Anwar A Chahal
- Center for Inherited Cardiovascular Diseases, WellSpan Health, Lancaster, PA, USA; Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS Trust, London, West Smithfield, EC1A 7BE, UK; Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA, USA; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.
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7
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Koopmann TT, Jamshidi Y, Naghibi-Sistani M, van der Klift HM, Birjandi H, Al-Hassnan Z, Alwadai A, Zifarelli G, Karimiani EG, Sedighzadeh S, Bahreini A, Nouri N, Peter M, Watanabe K, van Duyvenvoorde HA, Ruivenkamp CAL, Teunissen AKK, Ten Harkel ADJ, van Duinen SG, Haak MC, Prada CE, Santen GWE, Maroofian R. Biallelic loss of LDB3 leads to a lethal pediatric dilated cardiomyopathy. Eur J Hum Genet 2023; 31:97-104. [PMID: 36253531 PMCID: PMC9823012 DOI: 10.1038/s41431-022-01204-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 02/08/2023] Open
Abstract
Autosomal dominant variants in LDB3 (also known as ZASP), encoding the PDZ-LIM domain-binding factor, have been linked to a late onset phenotype of cardiomyopathy and myofibrillar myopathy in humans. However, despite knockout mice displaying a much more severe phenotype with premature death, bi-allelic variants in LDB3 have not yet been reported. Here we identify biallelic loss-of-function variants in five unrelated cardiomyopathy families by next-generation sequencing. In the first family, we identified compound heterozygous LOF variants in LDB3 in a fetus with bilateral talipes and mild left cardiac ventricular enlargement. Ultra-structural examination revealed highly irregular Z-disc formation, and RNA analysis demonstrated little/no expression of LDB3 protein with a functional C-terminal LIM domain in muscle tissue from the affected fetus. In a second family, a homozygous LDB3 nonsense variant was identified in a young girl with severe early-onset dilated cardiomyopathy with left ventricular non-compaction; the same homozygous nonsense variant was identified in a third unrelated female infant with dilated cardiomyopathy. We further identified homozygous LDB3 frameshift variants in two unrelated probands diagnosed with cardiomegaly and severely reduced left ventricular ejection fraction. Our findings demonstrate that recessive LDB3 variants can lead to an early-onset severe human phenotype of cardiomyopathy and myopathy, reminiscent of the knockout mouse phenotype, and supporting a loss of function mechanism.
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Affiliation(s)
- Tamara T. Koopmann
- grid.10419.3d0000000089452978Department of Clinical Genetics/LDGA, Leiden University Medical Center, Leiden, The Netherlands
| | - Yalda Jamshidi
- grid.264200.20000 0000 8546 682XGenetics Research Centre, Molecular and Clinical Sciences Institute, St George’s University of London, London, UK
| | - Mohammad Naghibi-Sistani
- grid.411583.a0000 0001 2198 6209Pediatric & Congenital Cardiology Division, Pediatric Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Heleen M. van der Klift
- grid.10419.3d0000000089452978Department of Clinical Genetics/LDGA, Leiden University Medical Center, Leiden, The Netherlands
| | - Hassan Birjandi
- grid.411583.a0000 0001 2198 6209Pediatric & Congenital Cardiology Division, Pediatric Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zuhair Al-Hassnan
- grid.415310.20000 0001 2191 4301The Cardiovascular Genetics Program, Centre for Genomic Medicine, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Abdullah Alwadai
- grid.415989.80000 0000 9759 8141PICU Department, Prince Sultan Cardiac Center, Riyadh, Saudi Arabia
| | - Giovanni Zifarelli
- grid.511058.80000 0004 0548 4972CENTOGENE GmbH, Am Strande 7, 18055 Rostock, Germany
| | - Ehsan G. Karimiani
- grid.264200.20000 0000 8546 682XGenetics Research Centre, Molecular and Clinical Sciences Institute, St George’s University of London, London, UK ,Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad, Iran
| | - Sahar Sedighzadeh
- grid.412504.60000 0004 0612 5699Department of Biological Sciences, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran ,KaryoGen, Isfahan, Iran
| | - Amir Bahreini
- KaryoGen, Isfahan, Iran ,grid.21925.3d0000 0004 1936 9000Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA USA
| | - Nayereh Nouri
- KaryoGen, Isfahan, Iran ,grid.411036.10000 0001 1498 685XDepartment of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Merlene Peter
- grid.413808.60000 0004 0388 2248Division of Genetics, Birth Defects & Metabolism, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL 60611 USA
| | - Kyoko Watanabe
- grid.413808.60000 0004 0388 2248Division of Cardiology, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL 60611 USA
| | - Hermine A. van Duyvenvoorde
- grid.10419.3d0000000089452978Department of Clinical Genetics/LDGA, Leiden University Medical Center, Leiden, The Netherlands
| | - Claudia A. L. Ruivenkamp
- grid.10419.3d0000000089452978Department of Clinical Genetics/LDGA, Leiden University Medical Center, Leiden, The Netherlands
| | - Aalbertine K. K. Teunissen
- grid.10419.3d0000000089452978Department of Obstetrics and Prenatal Diagnosis, Leiden University Medical Center, Leiden, The Netherlands
| | - Arend D. J. Ten Harkel
- grid.10419.3d0000000089452978Department of Pediatric Cardiology, Willem Alexander Children’s Hospital, Leiden University Medical Center, Leiden, The Netherlands
| | - Sjoerd G. van Duinen
- grid.10419.3d0000000089452978Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Monique C. Haak
- grid.10419.3d0000000089452978Department of Pediatric Cardiology, Willem Alexander Children’s Hospital, Leiden University Medical Center, Leiden, The Netherlands
| | - Carlos E. Prada
- grid.413808.60000 0004 0388 2248Division of Genetics, Birth Defects & Metabolism, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL 60611 USA ,grid.16753.360000 0001 2299 3507Department of Pediatrics, Feinberg School of Medicine of Northwestern University, Chicago, IL 60611 USA
| | - Gijs W. E. Santen
- grid.10419.3d0000000089452978Department of Clinical Genetics/LDGA, Leiden University Medical Center, Leiden, The Netherlands
| | - Reza Maroofian
- grid.83440.3b0000000121901201Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
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8
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Parker LE, Kramer RJ, Kaplan S, Landstrom AP. One gene, two modes of inheritance, four diseases: A systematic review of the cardiac manifestation of pathogenic variants in JPH2-encoded junctophilin-2. Trends Cardiovasc Med 2023; 33:1-10. [PMID: 34861382 PMCID: PMC9156715 DOI: 10.1016/j.tcm.2021.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 02/01/2023]
Abstract
Rare variants in JPH2 have been associated with a range of cardiac disease, including hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmias, and sudden cardiac death (SCD); however, our understanding of how variants in JPH2 correspond to specific modes of inheritance and correlate clinical phenotypes has not been comprehensively explored. In this systematic review, we assess current case reports and series that describe patients with JPH2 variants and cardiac disease. We identified a total of 61 variant-positive individuals, approximately 80% of whom had some form of cardiac disease, including 47% HCM, 18% DCM, and 14% arrhythmia/SCD. In analyzing the 24 probands described in the studies, we found that autosomal recessive, loss-of-function variants are associated with severe, early onset DCM, while autosomal dominant missense variants are associated with a wider range of cardiac disease, including HCM, arrhythmia, SCD, and cardiac conduction disease.
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Affiliation(s)
- Lauren E Parker
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States
| | - Ryan J Kramer
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States
| | - Samantha Kaplan
- Medical Center Library and Archives, Duke University, Durham, NC, United States
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States; Department of Cell Biology, Duke University School of Medicine, Durham, NC, United States.
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9
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Yang Q, Berkman AM, Ezekian JE, Rosamilia M, Rosenfeld JA, Liu P, Landstrom AP. Determining the Likelihood of Disease Pathogenicity Among Incidentally Identified Genetic Variants in Rare Dilated Cardiomyopathy-Associated Genes. J Am Heart Assoc 2022; 11:e025257. [PMID: 36129056 DOI: 10.1161/jaha.122.025257] [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
Background As utilization of clinical exome sequencing (ES) has expanded, criteria for evaluating the diagnostic weight of incidentally identified variants are critical to guide clinicians and researchers. This is particularly important in genes associated with dilated cardiomyopathy (DCM), which can cause heart failure and sudden death. We sought to compare the frequency and distribution of incidentally identified variants in DCM-associated genes between a clinical referral cohort with those in control and known case cohorts to determine the likelihood of pathogenicity among those undergoing genetic testing for non-DCM indications. Methods and Results A total of 39 rare, non-TTN DCM-associated genes were identified and evaluated from a clinical ES testing referral cohort (n=14 005, Baylor Genetic Laboratories) and compared with a DCM case cohort (n=9442) as well as a control cohort of population variants (n=141 456) derived from the gnomAD database. Variant frequencies in each cohort were compared. Signal-to-noise ratios were calculated comparing the DCM and ES cohort with the gnomAD cohort. The likely pathogenic/pathogenic variant yield in the DCM cohort (8.2%) was significantly higher than in the ES cohort (1.9%). Based on signal-to-noise and correlation analysis, incidental variants found in FLNC, RBM20, MYH6, DSP, ABCC9, JPH2, and NEXN had the greatest chance of being DCM-associated. Conclusions The distribution of pathogenic variants between the ES cohort and the DCM case cohort was gene specific, and variants found in the ES cohort were similar to variants found in the control cohort. Incidentally identified variants in specific genes are more associated with DCM than others.
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Affiliation(s)
- Qixin Yang
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC.,Department of Cardiology The First Affiliated Hospital, College of Medicine, Zhejiang University Hangzhou China
| | - Amy M Berkman
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC
| | - Jordan E Ezekian
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC
| | - Michael Rosamilia
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics Baylor College of Medicine and Baylor Genetics Laboratories Houston TX
| | - Pengfei Liu
- Department of Molecular and Human Genetics Baylor College of Medicine and Baylor Genetics Laboratories Houston TX
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC.,Department of Cell Biology Duke University School of Medicine Durham NC
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10
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Yang ZF, Panwar P, McFarlane CR, Tuinte WE, Campiglio M, Van Petegem F. Structures of the junctophilin/voltage-gated calcium channel interface reveal hot spot for cardiomyopathy mutations. Proc Natl Acad Sci U S A 2022; 119:e2120416119. [PMID: 35238659 PMCID: PMC8916002 DOI: 10.1073/pnas.2120416119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/31/2022] [Indexed: 01/19/2023] Open
Abstract
SignificanceIon channels have evolved the ability to communicate with one another, either through protein-protein interactions, or indirectly via intermediate diffusible messenger molecules. In special cases, the channels are part of different membranes. In muscle tissue, the T-tubule membrane is in proximity to the sarcoplasmic reticulum, allowing communication between L-type calcium channels and ryanodine receptors. This process is critical for excitation-contraction coupling and requires auxiliary proteins like junctophilin (JPH). JPHs are targets for disease-associated mutations, most notably hypertrophic cardiomyopathy mutations in the JPH2 isoform. Here we provide high-resolution snapshots of JPH, both alone and in complex with a calcium channel peptide, and show how this interaction is targeted by cardiomyopathy mutations.
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Affiliation(s)
- Zheng Fang Yang
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ciaran R. McFarlane
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Wietske E. Tuinte
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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11
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Minor hypertrophic cardiomyopathy genes, major insights into the genetics of cardiomyopathies. Nat Rev Cardiol 2022; 19:151-167. [PMID: 34526680 DOI: 10.1038/s41569-021-00608-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/02/2021] [Indexed: 01/06/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) was traditionally described as an autosomal dominant Mendelian disease but is now increasingly recognized as having a complex genetic aetiology. Although eight core genes encoding sarcomeric proteins account for >90% of the pathogenic variants in patients with HCM, variants in several additional genes (ACTN2, ALPK3, CSRP3, FHOD3, FLNC, JPH2, KLHL24, PLN and TRIM63), encoding non-sarcomeric proteins with diverse functions, have been shown to be disease-causing in a small number of patients. Genome-wide association studies (GWAS) have identified numerous loci in cardiomyopathy case-control studies and biobank investigations of left ventricular functional traits. Genes associated with Mendelian cardiomyopathy are enriched in the putative causal gene lists at these loci. Intriguingly, many loci are associated with both HCM and dilated cardiomyopathy but with opposite directions of effect on left ventricular traits, highlighting a genetic basis underlying the contrasting pathophysiological effects observed in each condition. This overlap extends to rare Mendelian variants with distinct variant classes in several genes associated with HCM and dilated cardiomyopathy. In this Review, we appraise the complex contribution of the non-sarcomeric, HCM-associated genes to cardiomyopathies across a range of variant classes (from common non-coding variants of individually low effect size to complete gene knockouts), which provides insights into the genetic basis of cardiomyopathies, causal genes at GWAS loci and the application of clinical genetic testing.
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12
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Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
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13
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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14
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Parker LE, Landstrom AP. The clinical utility of pediatric cardiomyopathy genetic testing: From diagnosis to a precision medicine-based approach to care. PROGRESS IN PEDIATRIC CARDIOLOGY 2021; 62. [PMID: 34776723 DOI: 10.1016/j.ppedcard.2021.101413] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Pediatric-onset cardiomyopathies are rare yet cause significant morbidity and mortality in affected children. Genetic testing has a major role in the clinical evaluation of pediatric-onset cardiomyopathies, and identification of a variant in an associated gene can be used to confirm the clinical diagnosis and exclude syndromic causes that may warrant different treatment strategies. Further, risk-predictive testing of first-degree relatives can assess who is at-risk of disease and requires continued clinical follow-up. Aim of Review In this review, we seek to describe the current role of genetic testing in the clinical diagnosis and management of patients and families with the five major cardiomyopathies. Further, we highlight the ongoing development of precision-based approaches to diagnosis, prognosis, and treatment. Key Scientific Concepts of Review Emerging application of genotype-phenotype correlations opens the door for genetics to guide a precision medicine-based approach to prognosis and potentially for therapies. Despite advances in our understanding of the genetic etiology of cardiomyopathy and increased accessibility of clinical genetic testing, not all pediatric cardiomyopathy patients have a clear genetic explanation for their disease. Expanded genomic studies are needed to understand the cause of disease in these patients, improve variant classification and genotype-driven prognostic predictions, and ultimately develop truly disease preventing treatment.
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Affiliation(s)
- Lauren E Parker
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States.,Department of Cell Biology, Duke University School of Medicine, Durham, NC, United States
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15
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Marian AJ, Asatryan B, Wehrens XHT. Genetic basis and molecular biology of cardiac arrhythmias in cardiomyopathies. Cardiovasc Res 2021; 116:1600-1619. [PMID: 32348453 DOI: 10.1093/cvr/cvaa116] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/09/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias are common, often the first, and sometimes the life-threatening manifestations of hereditary cardiomyopathies. Pathogenic variants in several genes known to cause hereditary cardiac arrhythmias have also been identified in the sporadic cases and small families with cardiomyopathies. These findings suggest a shared genetic aetiology of a subset of hereditary cardiomyopathies and cardiac arrhythmias. The concept of a shared genetic aetiology is in accord with the complex and exquisite interplays that exist between the ion currents and cardiac mechanical function. However, neither the causal role of cardiac arrhythmias genes in cardiomyopathies is well established nor the causal role of cardiomyopathy genes in arrhythmias. On the contrary, secondary changes in ion currents, such as post-translational modifications, are common and contributors to the pathogenesis of arrhythmias in cardiomyopathies through altering biophysical and functional properties of the ion channels. Moreover, structural changes, such as cardiac hypertrophy, dilatation, and fibrosis provide a pro-arrhythmic substrate in hereditary cardiomyopathies. Genetic basis and molecular biology of cardiac arrhythmias in hereditary cardiomyopathies are discussed.
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Affiliation(s)
- Ali J Marian
- Department of Medicine, Center for Cardiovascular Genetics, Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, 6770 Bertner Street, Suite C900A, Houston, TX 77030, USA
| | - Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Xander H T Wehrens
- Department of Biophysics and Molecular Physiology, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
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16
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Targeting JP2: A New Treatment for Pulmonary Hypertension. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:2003446. [PMID: 34394822 PMCID: PMC8363443 DOI: 10.1155/2021/2003446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 12/16/2022]
Abstract
Pulmonary hypertension (PH) is a disease with a complex etiology and high mortality rate. Abnormal pulmonary vasoconstriction and pulmonary vascular remodeling lead to an increase in mean pulmonary arterial blood pressure for which, and there is currently no cure. Junctophilin-2 (JP2) is beneficial for the assembly of junctional membrane complexes, the structural basis for excitation-contraction coupling that tethers the plasma membrane to the sarcoplasmic reticulum/endoplasmic reticulum and is involved in maintaining intracellular calcium concentration homeostasis and normal muscle contraction function. Recent studies have shown that JP2 maintains normal contraction and relaxation of vascular smooth muscle. In some experimental studies of drug treatments for PH, JP2 expression was increased, which improved pulmonary vascular remodeling and right ventricular function. Based on JP2 research to date, this paper summarizes the current understanding of JP2 protein structure, function, and related heart diseases and mechanisms and analyzes the feasibility and possible therapeutic strategies for targeting JP2 in PH.
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17
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Guo A, Fang W, Gibson S. Sequence determinants of human junctophilin-2 protein nuclear localization and phase separation. Biochem Biophys Res Commun 2021; 563:79-84. [PMID: 34062390 DOI: 10.1016/j.bbrc.2021.05.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 05/20/2021] [Accepted: 05/20/2021] [Indexed: 10/21/2022]
Abstract
Junctophilin-2 (JPH2) was conventionally considered as a structural membrane binding protein. Recently, it was shown that proteolytically truncated mouse JPH2 variants are imported into nucleus to exert alternative functions. However, the intranuclear behaviors of human JPH2 (hJPH2) and underlying molecular determinants have not been explored. Here, we demonstrate that full-length hJPH2 is imported into nucleus in human cells by two nuclear localization signals (NLSs), including a newly discovered one at the C-terminus. Importantly, unlike the JPH2 N-terminal truncation which diffuses throughout the nucleus, full-length hJPH2 forms nuclear bodies behaving like liquid-liquid phase separated droplets that are separated from chromatin. The C-terminal transmembrane domain is required for the formation of hJPH2 droplets. Oxidation mimicking substitution of residues C678 and M679 augments the formation of hJPH2 nuclear droplets, suggesting nuclear hJPH2 liquid-liquid phase separation could be modulated by oxidative stress. Mutation A405D, which introduces a negatively charged residue into an intrinsic disordered region (IDR) of hJPH2, turns liquid-like droplets into amyloid-like aggregates. Depletion of an Alanine Rich Region in the IDR recapitulates the liquid-amyloid phase transition. The MORN repeat regions of hJPH2 encodes intrinsic tendency to form amyloid-like structure. Together, these data revealed the novel intrinsic properties of hJPH2 to form nuclear liquid droplets, and identified critical functional domains encoding these properties. We propose that hJPH2 droplets could function as membrane-less organelles participating in nuclear regulatory processes.
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Affiliation(s)
- Ang Guo
- Department of Pharmaceutical Sciences, North Dakota State University, 1401 Albrecht Blvd, Fargo, ND, 58102, USA.
| | - Wenjuan Fang
- Department of Pharmaceutical Sciences, North Dakota State University, 1401 Albrecht Blvd, Fargo, ND, 58102, USA
| | - Savannah Gibson
- Department of Pharmaceutical Sciences, North Dakota State University, 1401 Albrecht Blvd, Fargo, ND, 58102, USA
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18
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Qiao Q, Zhao CM, Yang CX, Gu JN, Guo YH, Zhang M, Li RG, Qiu XB, Xu YJ, Yang YQ. Detection and functional characterization of a novel MEF2A variation responsible for familial dilated cardiomyopathy. Clin Chem Lab Med 2020; 59:955-963. [PMID: 33554560 DOI: 10.1515/cclm-2020-1318] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/25/2020] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Dilated cardiomyopathy (DCM) represents the most frequent form of cardiomyopathy, leading to heart failure, cardiac arrhythmias and death. Accumulating evidence convincingly demonstrates the crucial role of genetic defects in the pathogenesis of DCM, and over 100 culprit genes have been implicated with DCM. However, DCM is of substantial genetic heterogeneity, and the genetic determinants underpinning DCM remain largely elusive. METHODS Whole-exome sequencing and bioinformatical analyses were implemented in a consanguineous Chinese family with DCM. A total of 380 clinically annotated control individuals and 166 more DCM index cases then underwent Sanger sequencing analysis for the identified genetic variation. The functional characteristics of the variant were delineated by utilizing a dual-luciferase assay system. RESULTS A heterozygous variation in the MEF2A gene (encoding myocyte enhancer factor 2A, a transcription factor pivotal for embryonic cardiogenesis and postnatal cardiac adaptation), NM_001365204.1: c.718G>T; p. (Gly240*), was identified, and verified by Sanger sequencing to segregate with autosome-dominant DCM in the family with complete penetrance. The nonsense variation was neither detected in 760 control chromosomes nor found in 166 more DCM probands. Functional analyses revealed that the variant lost transactivation on the validated target genes MYH6 and FHL2, both causally linked to DCM. Furthermore, the variation nullified the synergistic activation between MEF2A and GATA4, another key transcription factor involved in DCM. CONCLUSIONS The findings firstly indicate that MEF2A loss-of-function variation predisposes to DCM in humans, providing novel insight into the molecular mechanisms of DCM and suggesting potential implications for genetic testing and prognostic evaluation of DCM patients.
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Affiliation(s)
- Qi Qiao
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China
| | - Cui-Mei Zhao
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine, Shanghai, P.R. China
| | - Chen-Xi Yang
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China
| | - Jia-Ning Gu
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China
| | - Yu-Han Guo
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China
| | - Min Zhang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Ruo-Gu Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China.,Cardiovascular Research Laboratory, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China.,Center Laboratory, Shanghai Fifth People's Hospital, Fudan University, Shanghai, P.R. China
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19
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T-tubule remodeling in human hypertrophic cardiomyopathy. J Muscle Res Cell Motil 2020; 42:305-322. [PMID: 33222034 PMCID: PMC8332592 DOI: 10.1007/s10974-020-09591-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 10/22/2020] [Indexed: 11/17/2022]
Abstract
The highly organized transverse T-tubule membrane system represents the ultrastructural substrate for excitation–contraction coupling in ventricular myocytes. While the architecture and function of T-tubules have been well described in animal models, there is limited morpho-functional data on T-tubules in human myocardium. Hypertrophic cardiomyopathy (HCM) is a primary disease of the heart muscle, characterized by different clinical presentations at the various stages of its progression. Most HCM patients, indeed, show a compensated hypertrophic disease (“non-failing hypertrophic phase”), with preserved left ventricular function, and only a small subset of individuals evolves into heart failure (“end stage HCM”). In terms of T-tubule remodeling, the “end-stage” disease does not differ from other forms of heart failure. In this review we aim to recapitulate the main structural features of T-tubules during the “non-failing hypertrophic stage” of human HCM by revisiting data obtained from human myectomy samples. Moreover, by comparing pathological changes observed in myectomy samples with those introduced by acute (experimentally induced) detubulation, we discuss the role of T-tubular disruption as a part of the complex excitation–contraction coupling remodeling process that occurs during disease progression. Lastly, we highlight how T-tubule morpho-functional changes may be related to patient genotype and we discuss the possibility of a primitive remodeling of the T-tubule system in rare HCM forms associated with genes coding for proteins implicated in T-tubule structural integrity, formation and maintenance.
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20
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Miura A, Kondo H, Yamamoto T, Okumura Y, Nishio H. Sudden Unexpected Death of Infantile Dilated Cardiomyopathy with JPH2 and PKD1 Gene Variants. Int Heart J 2020; 61:1079-1083. [PMID: 32879264 DOI: 10.1536/ihj.20-155] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A Japanese girl with polycystic kidney disease (PKD) developed normally, but at 8 months of age, she was hospitalized for acute onset dyspnea. On the day after admission to hospital, her general condition suddenly became worse. An echocardiogram showed left ventricular dilatation with thin walls, severe mitral valve regurgitation, and a reduced ejection fraction. She died of acute cardiac failure 3 hours after the sudden change. Postmortem analysis with light microscopy showed disarray of cardiomyocytes without obvious infiltration of lymphocytes, and we diagnosed her heart failure as idiopathic dilated cardiomyopathy (DCM). Clinical exome sequencing showed compound heterozygous variants in JPH2 (p.T237A/p.I414L) and a heterozygous nonsense mutation in PKD1 (p.Q4193*). To date, several variants in the JPH2 gene have been reported to be pathogenic for adult-onset hypertrophic cardiomyopathy or DCM in an autosomal dominant manner and infantile-onset DCM in an autosomal recessive manner. Additionally, autosomal dominant polycystic kidney disease is a systemic disease associated with several extrarenal manifestations, such as cardiomyopathy. Here we report a sudden infant death case of DCM and discuss the genetic variants of DCM and PKD.
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Affiliation(s)
- Aya Miura
- Department of Legal Medicine, Hyogo College of Medicine
| | - Hidehito Kondo
- Department of Pediatrics, Japanese Red Cross Kyoto Daiichi Hospital
| | | | - Yasuko Okumura
- Department of Pediatrics, Japanese Red Cross Kyoto Daiichi Hospital
| | - Hajime Nishio
- Department of Legal Medicine, Hyogo College of Medicine
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21
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Essandoh K, Philippe JM, Jenkins PM, Brody MJ. Palmitoylation: A Fatty Regulator of Myocardial Electrophysiology. Front Physiol 2020; 11:108. [PMID: 32140110 PMCID: PMC7042378 DOI: 10.3389/fphys.2020.00108] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/30/2020] [Indexed: 01/02/2023] Open
Abstract
Regulation of cardiac physiology is well known to occur through the action of kinases that reversibly phosphorylate ion channels, calcium handling machinery, and signaling effectors. However, it is becoming increasingly apparent that palmitoylation or S-acylation, the post-translational modification of cysteines with saturated fatty acids, plays instrumental roles in regulating the localization, activity, stability, sorting, and function of numerous proteins, including proteins known to have essential functions in cardiomyocytes. However, the impact of this modification on cardiac physiology requires further investigation. S-acylation is catalyzed by the zDHHC family of S-acyl transferases that localize to intracellular organelle membranes or the sarcolemma. Recent work has begun to uncover functions of S-acylation in the heart, particularly in the regulation of cardiac electrophysiology, including modification of the sodium-calcium exchanger, phospholemman and the cardiac sodium pump, as well as the voltage-gated sodium channel. Elucidating the regulatory functions of zDHHC enzymes in cardiomyocytes and determination of how S-acylation is altered in the diseased heart will shed light on how these modifications participate in cardiac pathogenesis and potentially identify novel targets for the treatment of cardiovascular disease. Indeed, proteins with critical signaling roles in the heart are also S-acylated, including receptors and G-proteins, yet the dynamics and functions of these modifications in myocardial physiology have not been interrogated. Here, we will review what is known about zDHHC enzymes and substrate S-acylation in myocardial physiology and highlight future areas of investigation that will uncover novel functions of S-acylation in cardiac homeostasis and pathophysiology.
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Affiliation(s)
- Kobina Essandoh
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Julie M Philippe
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States.,Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Matthew J Brody
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
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