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Rahimzadeh M, Tennstedt S, Aherrahrou Z. Nexilin in cardiomyopathy: unveiling its diverse roles with special focus on endocardial fibroelastosis. Heart Fail Rev 2024; 29:1025-1037. [PMID: 38985384 DOI: 10.1007/s10741-024-10416-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/01/2024] [Indexed: 07/11/2024]
Abstract
Cardiac disorders exhibit considerable heterogeneity, and understanding their genetic foundations is crucial for their diagnosis and treatment. Recent genetic analyses involving a growing number of participants have uncovered novel mutations within both coding and non-coding regions of DNA, contributing to the onset of cardiac conditions. The NEXN gene, encoding the Nexilin protein, an actin filament-binding protein, is integral to normal cardiac function. Mutations in this gene have been linked to cardiomyopathies, cardiovascular disorders, and sudden deaths. Heterozygous or homozygous variants of the NEXN gene are associated with the development of endocardial fibroelastosis (EFE), a rare cardiac condition characterized by excessive collagen and elastin deposition in the left ventricular endocardium predominantly affecting infants and young children. EFE occurs both primary and secondary to other conditions and often leads to unfavorable prognoses and outcomes. This review explores the role of NEXN genetic variants in cardiovascular disorders, particularly EFE, revealing that functional mutations are not clustered in a specific domain of Nexilin based on the cardiac disorder phenotype. Our review underscores the importance of understanding genetic mutations for the diagnosis and treatment of cardiac conditions.
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Affiliation(s)
- Mahsa Rahimzadeh
- Cardiovascular Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
- Department of Biochemistry, Faculty of Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Stephanie Tennstedt
- Institute for Cardiogenetics, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
- DZHK (German Research Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, 23562, Germany
- University Heart Center Lübeck, Lübeck, 23562, Germany
| | - Zouhair Aherrahrou
- Institute for Cardiogenetics, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.
- DZHK (German Research Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, 23562, Germany.
- University Heart Center Lübeck, Lübeck, 23562, Germany.
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Bekele BM, Gazzerro E, Schoenrath F, Falk V, Rost S, Hoerning S, Jelting Y, Zaum AK, Spuler S, Knierim J. Undetected Neuromuscular Disease in Patients after Heart Transplantation. Int J Mol Sci 2024; 25:7819. [PMID: 39063061 PMCID: PMC11277526 DOI: 10.3390/ijms25147819] [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: 06/08/2024] [Revised: 07/10/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024] Open
Abstract
(1) Heart transplantation (HTX) improves the overall survival and functional status of end-stage heart failure patients with cardiomyopathies (CMPs). The majority of CMPs have genetic causes, and the overlap between CMPs and inherited myopathies is well documented. However, the long-term outcome in skeletal muscle function and possibility of an undiagnosed underlying genetic cause of both a cardiac and skeletal pathology remain unknown. (2) Thirty-nine patients were assessed using open and standardized interviews on muscle function, a quality-of-life (EuroQol EQ-5D-3L) questionnaire, and a physical examination (Medical Research Council Muscle scale). Whole-exome sequencing was completed in three stages for those with skeletal muscle weakness. (3) Seven patients (17.9%) reported new-onset muscle weakness and motor limitations. Objective muscle weakness in the upper and lower extremities was seen in four patients. In three of them, exome sequencing revealed pathogenic/likely pathogenic variants in the genes encoding nexilin, myosin heavy chain, titin, and SPG7. (4) Our findings support a positive long-term outcome of skeletal muscle function in HTX patients. However, 10% of patients showed clinical signs of myopathy due to a possible genetic cause. The integration of genetic testing and standardized neurological assessment of motor function during the peri-HTX period should be considered.
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Affiliation(s)
- Biniam Melese Bekele
- Muscle Research Unit, ECRC Experimental and Clinical Research Center, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Lindenberger Weg 80, 13125 Berlin, Germany; (B.M.B.); (E.G.)
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
- Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany (J.K.)
- Deutsches Herzzentrum der Charité—Medical Heart Center of Charité and German Heart Institute Berlin, Department of Cardiothoracic and Vascular Surgery, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Elisabetta Gazzerro
- Muscle Research Unit, ECRC Experimental and Clinical Research Center, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Lindenberger Weg 80, 13125 Berlin, Germany; (B.M.B.); (E.G.)
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Felix Schoenrath
- Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany (J.K.)
- Deutsches Herzzentrum der Charité—Medical Heart Center of Charité and German Heart Institute Berlin, Department of Cardiothoracic and Vascular Surgery, Augustenburger Platz 1, 13353 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner site Berlin, 13125 Berlin, Germany
| | - Volkmar Falk
- Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany (J.K.)
- Deutsches Herzzentrum der Charité—Medical Heart Center of Charité and German Heart Institute Berlin, Department of Cardiothoracic and Vascular Surgery, Augustenburger Platz 1, 13353 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner site Berlin, 13125 Berlin, Germany
- Translational Cardiovascular Technologies, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Simone Rost
- Institute for Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Selina Hoerning
- Institute for Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Yvonne Jelting
- Institute for Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Ann-Kathrin Zaum
- Institute for Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Simone Spuler
- Muscle Research Unit, ECRC Experimental and Clinical Research Center, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Lindenberger Weg 80, 13125 Berlin, Germany; (B.M.B.); (E.G.)
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
- Berlin Institute of Health at Charité—Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Jan Knierim
- Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany (J.K.)
- Sana Paulinenkrankenhaus, Department of Internal Medicine and Cardiology, Dickensweg 25-39, 14055 Berlin, Germany
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Shao Y, Liu C, Liao HK, Zhang R, Yuan B, Yang H, Li R, Zhu S, Fang X, Rodriguez Esteban C, Chen J, Izpisua Belmonte JC. In vivo rescue of genetic dilated cardiomyopathy by systemic delivery of nexilin. Genome Biol 2024; 25:135. [PMID: 38783323 PMCID: PMC11112773 DOI: 10.1186/s13059-024-03283-x] [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] [Received: 02/08/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Dilated cardiomyopathy (DCM) is one of the most common causes of heart failure. Multiple identified mutations in nexilin (NEXN) have been suggested to be linked with severe DCM. However, the exact association between multiple mutations of Nexn and DCM remains unclear. Moreover, it is critical for the development of precise and effective therapeutics in treatments of DCM. RESULTS In our study, Nexn global knockout mice and mice carrying human equivalent G645del mutation are studied using functional gene rescue assays. AAV-mediated gene delivery is conducted through systemic intravenous injections at the neonatal stage. Heart tissues are analyzed by immunoblots, and functions are assessed by echocardiography. Here, we identify functional components of Nexilin and demonstrate that exogenous introduction could rescue the cardiac function and extend the lifespan of Nexn knockout mouse models. Similar therapeutic effects are also obtained in G645del mice, providing a promising intervention for future clinical therapeutics. CONCLUSIONS In summary, we demonstrated that a single injection of AAV-Nexn was capable to restore the functions of cardiomyocytes and extended the lifespan of Nexn knockout and G645del mice. Our study represented a long-term gene replacement therapy for DCM that potentially covers all forms of loss-of-function mutations in NEXN.
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Affiliation(s)
- Yanjiao Shao
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Altos Labs, San Diego, CA, 92121, USA
| | - Canzhao Liu
- Department of Cardiology, Translational Medicine Research Center, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical University, Guangzhou, 510280, China
- Guangdong Provincial Biomedical Engineering Technology Research Center for Cardiovascular Disease, Guangzhou, 510280, China
| | - Hsin-Kai Liao
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Ran Zhang
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Baolei Yuan
- Altos Labs, San Diego, CA, 92121, USA
- King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Hanyan Yang
- Department of Cardiology, Translational Medicine Research Center, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical University, Guangzhou, 510280, China
- Guangdong Provincial Biomedical Engineering Technology Research Center for Cardiovascular Disease, Guangzhou, 510280, China
| | - Ronghui Li
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Altos Labs, San Diego, CA, 92121, USA
| | - Siting Zhu
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Concepcion Rodriguez Esteban
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Altos Labs, San Diego, CA, 92121, USA
| | - Ju Chen
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Juan Carlos Izpisua Belmonte
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
- Altos Labs, San Diego, CA, 92121, USA.
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Hermida A, Ader F, Millat G, Jedraszak G, Maury P, Cador R, Catalan PA, Clerici G, Combes N, De Groote P, Dupin-Deguine D, Eschalier R, Faivre L, Garcia P, Guillon B, Janin A, Kugener B, Lackmy M, Laredo M, Le Guillou X, Lesaffre F, Lucron H, Milhem A, Nadeau G, Nguyen K, Palmyre A, Perdreau E, Picard F, Rebotier N, Richard P, Rooryck C, Seitz J, Verloes A, Vernier A, Winum P, Yabeta GAD, Bouchot O, Chevalier P, Charron P, Gandjbakhch E. NEXN Gene in Cardiomyopathies and Sudden Cardiac Deaths: Prevalence, Phenotypic Expression, and Prognosis. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2024; 17:e004285. [PMID: 38059363 DOI: 10.1161/circgen.123.004285] [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: 06/14/2023] [Accepted: 11/05/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Few clinical data are available on NEXN mutation carriers, and the gene's involvement in cardiomyopathies or sudden death has not been fully established. Our objectives were to assess the prevalence of putative pathogenic variants in NEXN and to describe the phenotype and prognosis of patients carrying the variants. METHODS DNA samples from consecutive patients with cardiomyopathy or sudden cardiac death/sudden infant death syndrome/idiopathic ventricular fibrillation were sequenced with a custom panel of genes. Index cases carrying at least one putative pathogenic variant in the NEXN gene were selected. RESULTS Of the 9516 index patients sequenced, 31 were carriers of a putative pathogenic variant in NEXN only, including 2 with double variants and 29 with a single variant. Of the 29 unrelated probands with a single variant (16 males; median age at diagnosis, 32.0 [26.0-49.0] years), 21 presented with dilated cardiomyopathy (prevalence, 0.33%), and 3 presented with hypertrophic cardiomyopathy (prevalence, 0.14%). Three patients had idiopathic ventricular fibrillation, and there were 2 cases of sudden infant death syndrome (prevalence, 0.46%). For patients with dilated cardiomyopathy, the median left ventricle ejection fraction was 37.5% (26.25-50.0) at diagnosis and improved with treatment in 13 (61.9%). Over a median follow-up period of 6.0 years, we recorded 3 severe arrhythmic events and 2 severe hemodynamic events. CONCLUSIONS Putative pathogenic NEXN variants were mainly associated with dilated cardiomyopathy; in these individuals, the prognosis appeared to be relatively good. However, severe and early onset phenotypes were also observed-especially in patients with double NEXN variants. We also detected NEXN variants in patients with hypertrophic cardiomyopathy and sudden infant death syndrome/idiopathic ventricular fibrillation, although a causal link could not be established.
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Affiliation(s)
- Alexis Hermida
- Cardiology, Arrhythmia, and Cardiac Stimulation Service (A.H.), Amiens-Picardie University Hospital
- EA4666 HEMATIM, University of Picardie-Jules Verne, Amiens (A.H., G.J.)
- Institute of Cardiology and ICAN Institute for Cardiometabolism and Nutrition (A.H., M. Laredo, P. Charron, E.G.)
- Department of Genetics, Department of Cardiology, and Referral center for hereditary cardiac diseases, APHP, Pitié-Salpêtrière Hospital (A.H., P. Charron, E.G.)
| | - Flavie Ader
- Unité Pédagogique de Biochimie, Département des Sciences Biologiques et Médicales, UFR de Pharmacie-Faculté de Santé, Université Paris Cité (F.A.)
- Unité Fonctionnelle de Cardiogénétique et Myogénétique Moléculaire et Cellulaire, DMU Biogem, Service de Biochimie Métabolique, AP-HP-Sorbonne Université, Pitié-Salpêtrière -Charles Foix (F.A., P.R.)
- Sorbonne Université, INSERM 1166, Paris (F.A., M. Laredo, P.R., P. Charron, E.G.)
| | - Gilles Millat
- Service de Génétique Moléculaire, Hospices Civils de Lyon (G.M., A.J.)
| | - Guillaume Jedraszak
- Molecular Genetics Laboratory (G.J.), Amiens-Picardie University Hospital
- EA4666 HEMATIM, University of Picardie-Jules Verne, Amiens (A.H., G.J.)
| | | | - Romain Cador
- Service de Cardiologie, Hôpital Saint Joseph, Paris (R.C.)
| | | | - Gaël Clerici
- Service de Cardiologie, Centre hospitalier universitaire, Saint Pierre, La Réunion (G.C.)
| | - Nicolas Combes
- Service de Cardiologie, Clinique Pasteur, Toulouse (N.C.)
| | - Pascal De Groote
- France CHU Lille, Service de Cardiologie & Inserm U1167, Institut Pasteur de Lille (P.D.G.)
| | | | | | | | - Patricia Garcia
- Unité Mort Inattendue du Nourrisson, Hôpital de la Conception, APHM, Marseille (P.G.)
| | | | - Alexandre Janin
- Service de Génétique Moléculaire, Hospices Civils de Lyon (G.M., A.J.)
| | | | - Marylin Lackmy
- Unité de Génétique Clinique, CHU de Guadeloupe, Pointe à Pitre (M. Lackmy)
| | - Mikael Laredo
- Institute of Cardiology and ICAN Institute for Cardiometabolism and Nutrition (A.H., M. Laredo, P. Charron, E.G.)
- Sorbonne Université, INSERM 1166, Paris (F.A., M. Laredo, P.R., P. Charron, E.G.)
| | | | | | - Hugues Lucron
- Service de Cardiologie pédiatrique, CHU Martinique, Fort-de-France (H.L.)
| | | | - Gwenaël Nadeau
- Service de génétique clinique CH Métropole Savoie, Chambéry (G.N.)
| | | | - Aurélien Palmyre
- APHP, Ambroise Paré Hospital, Department of Genetics and Referral center for cardiac hereditary cardiac diseases, Boulogne-Billancourt (A.P., P. Charron)
| | - Elodie Perdreau
- Département médico chirurgical de cardiologie pédiatrique (E.P.), Hôpital Louis Pradel, HCL, Lyon
| | - François Picard
- Service de Cardiologie, Hôpital Cardiologique Haut Leveque, Bordeaux (F.P.)
| | | | - Pascale Richard
- Unité Fonctionnelle de Cardiogénétique et Myogénétique Moléculaire et Cellulaire, DMU Biogem, Service de Biochimie Métabolique, AP-HP-Sorbonne Université, Pitié-Salpêtrière -Charles Foix (F.A., P.R.)
- Sorbonne Université, INSERM 1166, Paris (F.A., M. Laredo, P.R., P. Charron, E.G.)
| | | | - Julien Seitz
- Service de Cardiologie, Hôpital Saint Joseph, Marseille (J.S.)
| | - Alain Verloes
- Departement de génétique, Hôpital Robert Debré, APHP (A. Verloes)
| | | | | | - Grace-A-Dieu Yabeta
- Service de Cardiologie, CH Ouest Guyane, Saint-Laurent-du-Maroni (G.-A.-D.Y.)
| | - Océane Bouchot
- Service de Cardiologie, CH Annecy Genevois, Annecy, France (O.B.)
| | | | - Philippe Charron
- Institute of Cardiology and ICAN Institute for Cardiometabolism and Nutrition (A.H., M. Laredo, P. Charron, E.G.)
- Department of Genetics, Department of Cardiology, and Referral center for hereditary cardiac diseases, APHP, Pitié-Salpêtrière Hospital (A.H., P. Charron, E.G.)
- Sorbonne Université, INSERM 1166, Paris (F.A., M. Laredo, P.R., P. Charron, E.G.)
- APHP, Ambroise Paré Hospital, Department of Genetics and Referral center for cardiac hereditary cardiac diseases, Boulogne-Billancourt (A.P., P. Charron)
| | - Estelle Gandjbakhch
- Institute of Cardiology and ICAN Institute for Cardiometabolism and Nutrition (A.H., M. Laredo, P. Charron, E.G.)
- Department of Genetics, Department of Cardiology, and Referral center for hereditary cardiac diseases, APHP, Pitié-Salpêtrière Hospital (A.H., P. Charron, E.G.)
- Sorbonne Université, INSERM 1166, Paris (F.A., M. Laredo, P.R., P. Charron, E.G.)
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Dixon RE, Trimmer JS. Endoplasmic Reticulum-Plasma Membrane Junctions as Sites of Depolarization-Induced Ca 2+ Signaling in Excitable Cells. Annu Rev Physiol 2023; 85:217-243. [PMID: 36202100 PMCID: PMC9918718 DOI: 10.1146/annurev-physiol-032122-104610] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane contact sites between endoplasmic reticulum (ER) and plasma membrane (PM), or ER-PM junctions, are found in all eukaryotic cells. In excitable cells they play unique roles in organizing diverse forms of Ca2+ signaling as triggered by membrane depolarization. ER-PM junctions underlie crucial physiological processes such as excitation-contraction coupling, smooth muscle contraction and relaxation, and various forms of activity-dependent signaling and plasticity in neurons. In many cases the structure and molecular composition of ER-PM junctions in excitable cells comprise important regulatory feedback loops linking depolarization-induced Ca2+ signaling at these sites to the regulation of membrane potential. Here, we describe recent findings on physiological roles and molecular composition of native ER-PM junctions in excitable cells. We focus on recent studies that provide new insights into canonical forms of depolarization-induced Ca2+ signaling occurring at junctional triads and dyads of striated muscle, as well as the diversity of ER-PM junctions in these cells and in smooth muscle and neurons.
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Affiliation(s)
- Rose E Dixon
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
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Noureddine M, Gehmlich K. Structural and signaling proteins in the Z-disk and their role in cardiomyopathies. Front Physiol 2023; 14:1143858. [PMID: 36935760 PMCID: PMC10017460 DOI: 10.3389/fphys.2023.1143858] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The sarcomere is the smallest functional unit of muscle contraction. It is delineated by a protein-rich structure known as the Z-disk, alternating with M-bands. The Z-disk anchors the actin-rich thin filaments and plays a crucial role in maintaining the mechanical stability of the cardiac muscle. A multitude of proteins interact with each other at the Z-disk and they regulate the mechanical properties of the thin filaments. Over the past 2 decades, the role of the Z-disk in cardiac muscle contraction has been assessed widely, however, the impact of genetic variants in Z-disk proteins has still not been fully elucidated. This review discusses the various Z-disk proteins (alpha-actinin, filamin C, titin, muscle LIM protein, telethonin, myopalladin, nebulette, and nexilin) and Z-disk-associated proteins (desmin, and obscurin) and their role in cardiac structural stability and intracellular signaling. This review further explores how genetic variants of Z-disk proteins are linked to inherited cardiac conditions termed cardiomyopathies.
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Affiliation(s)
- Maya Noureddine
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Maya Noureddine, ; Katja Gehmlich,
| | - Katja Gehmlich
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, United Kingdom
- *Correspondence: Maya Noureddine, ; Katja Gehmlich,
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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: 12] [Impact Index Per Article: 6.0] [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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8
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Powers JD, Kirkland NJ, Liu C, Razu SS, Fang X, Engler AJ, Chen J, McCulloch AD. Subcellular Remodeling in Filamin C Deficient Mouse Hearts Impairs Myocyte Tension Development during Progression of Dilated Cardiomyopathy. Int J Mol Sci 2022; 23:871. [PMID: 35055055 PMCID: PMC8779483 DOI: 10.3390/ijms23020871] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/28/2021] [Accepted: 01/11/2022] [Indexed: 01/15/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is a life-threatening form of heart disease that is typically characterized by progressive thinning of the ventricular walls, chamber dilation, and systolic dysfunction. Multiple mutations in the gene encoding filamin C (FLNC), an actin-binding cytoskeletal protein in cardiomyocytes, have been found in patients with DCM. However, the mechanisms that lead to contractile impairment and DCM in patients with FLNC variants are poorly understood. To determine how FLNC regulates systolic force transmission and DCM remodeling, we used an inducible, cardiac-specific FLNC-knockout (icKO) model to produce a rapid onset of DCM in adult mice. Loss of FLNC reduced systolic force development in single cardiomyocytes and isolated papillary muscles but did not affect twitch kinetics or calcium transients. Electron and immunofluorescence microscopy showed significant defects in Z-disk alignment in icKO mice and altered myofilament lattice geometry. Moreover, a loss of FLNC induces a softening myocyte cortex and structural adaptations at the subcellular level that contribute to disrupted longitudinal force production during contraction. Spatially explicit computational models showed that these structural defects could be explained by a loss of inter-myofibril elastic coupling at the Z-disk. Our work identifies FLNC as a key regulator of the multiscale ultrastructure of cardiomyocytes and therefore plays an important role in maintaining systolic mechanotransmission pathways, the dysfunction of which may be key in driving progressive DCM.
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Affiliation(s)
- Joseph D. Powers
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Natalie J. Kirkland
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Canzhao Liu
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
| | - Swithin S. Razu
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
| | - Adam J. Engler
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Ju Chen
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
| | - Andrew D. McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
- Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA
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9
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Setterberg IE, Le C, Frisk M, Li J, Louch WE. The Physiology and Pathophysiology of T-Tubules in the Heart. Front Physiol 2021; 12:718404. [PMID: 34566684 PMCID: PMC8458775 DOI: 10.3389/fphys.2021.718404] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/07/2021] [Indexed: 12/18/2022] Open
Abstract
In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling. These structures form functional junctions with the sarcoplasmic reticulum (SR), and thereby enable close contact between L-type Ca2+ channels (LTCCs) and Ryanodine Receptors (RyRs). This arrangement in turn ensures efficient triggering of Ca2+ release, and contraction. While new data indicate that t-tubules are capable of exhibiting compensatory remodeling, they are also widely reported to be structurally and functionally compromised during disease, resulting in disrupted Ca2+ homeostasis, impaired systolic and/or diastolic function, and arrhythmogenesis. This review summarizes these findings, while highlighting an emerging appreciation of the distinct roles of t-tubules in the pathophysiology of heart failure with reduced and preserved ejection fraction (HFrEF and HFpEF). In this context, we review current understanding of the processes underlying t-tubule growth, maintenance, and degradation, underscoring the involvement of a variety of regulatory proteins, including junctophilin-2 (JPH2), amphiphysin-2 (BIN1), caveolin-3 (Cav3), and newer candidate proteins. Upstream regulation of t-tubule structure/function by cardiac workload and specifically ventricular wall stress is also discussed, alongside perspectives for novel strategies which may therapeutically target these mechanisms.
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Affiliation(s)
- Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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10
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Biquand A, Spinozzi S, Tonino P, Cosette J, Strom J, Elbeck Z, Knöll R, Granzier H, Lostal W, Richard I. Titin M-line insertion sequence 7 is required for proper cardiac function in mice. J Cell Sci 2021; 134:271843. [PMID: 34401916 DOI: 10.1242/jcs.258684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/06/2021] [Indexed: 11/20/2022] Open
Abstract
Titin is a giant sarcomeric protein that is involved in a large number of functions, with a primary role in skeletal and cardiac sarcomere organization and stiffness. The titin gene (TTN) is subject to various alternative splicing events, but in the region that is present at the M-line, the only exon that can be spliced out is Mex5, which encodes for the insertion sequence 7 (is7). Interestingly, in the heart, the majority of titin isoforms are Mex5+, suggesting a cardiac role for is7. Here, we performed comprehensive functional, histological, transcriptomic, microscopic and molecular analyses of a mouse model lacking the Ttn Mex5 exon (ΔMex5), and revealed that the absence of the is7 is causative for dilated cardiomyopathy. ΔMex5 mice showed altered cardiac function accompanied by increased fibrosis and ultrastructural alterations. Abnormal expression of excitation-contraction coupling proteins was also observed. The results reported here confirm the importance of the C-terminal region of titin in cardiac function and are the first to suggest a possible relationship between the is7 and excitation-contraction coupling. Finally, these findings give important insights for the identification of new targets in the treatment of titinopathies.
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Affiliation(s)
- Ariane Biquand
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Simone Spinozzi
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Paola Tonino
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | | | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - Zaher Elbeck
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institutet, 141 57 Huddinge, Sweden
| | - Ralph Knöll
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institutet, 141 57 Huddinge, Sweden.,Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, 431 50 Gothenburg, Sweden
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - William Lostal
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Isabelle Richard
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
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