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Bueno‐Beti C, Lim CX, Protonotarios A, Szabo PL, Westaby J, Mazic M, Sheppard MN, Behr E, Hamza O, Kiss A, Podesser BK, Hengstschläger M, Weichhart T, Asimaki A. An mTORC1-Dependent Mouse Model for Cardiac Sarcoidosis. J Am Heart Assoc 2023; 12:e030478. [PMID: 37750561 PMCID: PMC10727264 DOI: 10.1161/jaha.123.030478] [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] [Received: 06/22/2023] [Accepted: 08/15/2023] [Indexed: 09/27/2023]
Abstract
Background Sarcoidosis is an inflammatory, granulomatous disease of unknown cause affecting multiple organs, including the heart. Untreated, unresolved granulomatous inflammation can lead to cardiac fibrosis, arrhythmias, and eventually heart failure. Here we characterize the cardiac phenotype of mice with chronic activation of mammalian target of rapamycin (mTOR) complex 1 signaling in myeloid cells known to cause spontaneous pulmonary sarcoid-like granulomas. Methods and Results The cardiac phenotype of mice with conditional deletion of the tuberous sclerosis 2 (TSC2) gene in CD11c+ cells (TSC2fl/flCD11c-Cre; termed TSC2KO) and controls (TSC2fl/fl) was determined by histological and immunological stains. Transthoracic echocardiography and invasive hemodynamic measurements were performed to assess myocardial function. TSC2KO animals were treated with either everolimus, an mTOR inhibitor, or Bay11-7082, a nuclear factor-kB inhibitor. Activation of mTOR signaling was evaluated on myocardial samples from sudden cardiac death victims with a postmortem diagnosis of cardiac sarcoidosis. Chronic activation of mTORC1 signaling in CD11c+ cells was sufficient to initiate progressive accumulation of granulomatous infiltrates in the heart, which was associated with increased fibrosis, impaired cardiac function, decreased plakoglobin expression, and abnormal connexin 43 distribution, a substrate for life-threatening arrhythmias. Mice treated with the mTOR inhibitor everolimus resolved granulomatous infiltrates, prevented fibrosis, and improved cardiac dysfunction. In line, activation of mTOR signaling in CD68+ macrophages was detected in the hearts of sudden cardiac death victims who suffered from cardiac sarcoidosis. Conclusions To our best knowledge this is the first animal model of cardiac sarcoidosis that recapitulates major pathological hallmarks of human disease. mTOR inhibition may be a therapeutic option for patients with cardiac sarcoidosis.
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Affiliation(s)
- Carlos Bueno‐Beti
- Clinical Cardiology Academic Group, Molecular and Clinical Research Science InstituteSt George’s University of LondonLondonUnited Kingdom
| | - Clarice X. Lim
- Center for Pathobiochemistry and GeneticsMedical University of ViennaViennaAustria
| | - Alexandros Protonotarios
- Institute of Cardiovascular Science, Clinical Science Research GroupUniversity College LondonLondonUnited Kingdom
| | - Petra Lujza Szabo
- Center for Biomedical ResearchMedical University of ViennaViennaAustria
| | - Joseph Westaby
- Clinical Cardiology Academic Group, Molecular and Clinical Research Science InstituteSt George’s University of LondonLondonUnited Kingdom
| | - Mario Mazic
- Center for Pathobiochemistry and GeneticsMedical University of ViennaViennaAustria
| | - Mary N. Sheppard
- Clinical Cardiology Academic Group, Molecular and Clinical Research Science InstituteSt George’s University of LondonLondonUnited Kingdom
| | - Elijah Behr
- Clinical Cardiology Academic Group, Molecular and Clinical Research Science InstituteSt George’s University of LondonLondonUnited Kingdom
| | - Ouafa Hamza
- Center for Biomedical ResearchMedical University of ViennaViennaAustria
| | - Attila Kiss
- Center for Biomedical ResearchMedical University of ViennaViennaAustria
| | - Bruno K. Podesser
- Center for Biomedical ResearchMedical University of ViennaViennaAustria
| | | | - Thomas Weichhart
- Center for Pathobiochemistry and GeneticsMedical University of ViennaViennaAustria
| | - Angeliki Asimaki
- Clinical Cardiology Academic Group, Molecular and Clinical Research Science InstituteSt George’s University of LondonLondonUnited Kingdom
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Bueno-Beti C, Asimaki A. Cheek-Pro-Heart: What Can the Buccal Mucosa Do for Arrhythmogenic Cardiomyopathy? Biomedicines 2023; 11:biomedicines11041207. [PMID: 37189825 DOI: 10.3390/biomedicines11041207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is a heart muscle disease associated with ventricular arrhythmias and a high risk of sudden cardiac death (SCD). Although the disease was described over 40 years ago, its diagnosis is still difficult. Several studies have identified a set of five proteins (plakoglobin, Cx43, Nav1.5, SAP97 and GSK3β), which are consistently re-distributed in myocardial samples from ACM patients. Not all protein shifts are specific to ACM, but their combination has provided us with a molecular signature for the disease, which has greatly aided post-mortem diagnosis of SCD victims. The use of this signature, however, was heretofore restricted in living patients, as the analysis requires a heart sample. Recent studies have shown that buccal cells behave similarly to the heart in terms of protein re-localization. Protein shifts are associated with disease onset, deterioration and favorable response to anti-arrhythmic therapy. Accordingly, buccal cells can be used as a surrogate for the myocardium to aid diagnosis, risk stratification and even monitor response to pharmaceutical interventions. Buccal cells can also be kept in culture, hence providing an ex vivo model from the patient, which can offer insights into the mechanisms of disease pathogenesis, including drug response. This review summarizes how the cheek can aid the heart in the battle against ACM.
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Affiliation(s)
- Carlos Bueno-Beti
- Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, UK
| | - Angeliki Asimaki
- Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, UK
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Hung PF, Chung FP, Hung CL, Lin YJ, Kuo TT, Liao JN, Chen YY, Pan CH, Shaw KP, Chen SA. Decreased Expression of Plakophilin-2 and αT-Catenin in Arrhythmogenic Right Ventricular Cardiomyopathy: Potential Markers for Diagnosis. Int J Mol Sci 2022; 23:ijms23105529. [PMID: 35628349 PMCID: PMC9141850 DOI: 10.3390/ijms23105529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 02/01/2023] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary disease of the heart muscle. Clinical challenges remain, however, in identifying patients with ARVC in the early or concealed stages with subtle clinical manifestations. Therefore, we wanted to identify potential targets by immunohistochemical (IHC) analysis in comparison with controls. Pathogenic mutations were identified in 11 of 37 autopsied patients with ARVC. As observed from IHC analysis of the RV, expression of αT-catenin and plakophilin-2 is significantly decreased in autopsied patients with ARVC as compared to controls, and the decreased expression is consistent in patients with and without pathogenic mutations. Furthermore, ARVC specimens demonstrated a reduced localization of αT-catenin, desmocollin-2, desmoglein-2, desmoplakin, and plakophilin-2 on intercalated discs. These findings have been validated by comparing RV specimens obtained via endomyocardial biopsy between patients with ARVC and those without. The pathogenic mutation was present in 3 of 5 clinical patients with ARVC. In HL-1 myocytes, siRNA was used to knockdown CTNNA3, and western blotting analysis demonstrated that the decline in αT-catenin expression was accompanied by a significant decline in the expression of plakophilin-2. The aforementioned effect was directed towards protein degradation rather than mRNA stability. Plakophilin-2 expression decreases concurrently with the decline in CTNNA3 expression. Therefore, the expression of αT-catenin and plakophilin-2 could be potential surrogates for the diagnosis of ARVC.
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Affiliation(s)
- Pei-Fang Hung
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112201, Taiwan; (P.-F.H.); (Y.-J.L.); (J.-N.L.); (Y.-Y.C.); (S.-A.C.)
| | - Fa-Po Chung
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112201, Taiwan; (P.-F.H.); (Y.-J.L.); (J.-N.L.); (Y.-Y.C.); (S.-A.C.)
- Institute of Clinical Medicine and Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
- Correspondence:
| | - Chung-Lieh Hung
- Department of Medicine, Mackay Medical College, New Taipei City 252005, Taiwan;
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City 252005, Taiwan
- Division of Cardiology, Department of Internal Medicine, Mackay Memorial Hospital, Taipei 104217, Taiwan
| | - Yenn-Jiang Lin
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112201, Taiwan; (P.-F.H.); (Y.-J.L.); (J.-N.L.); (Y.-Y.C.); (S.-A.C.)
- Institute of Clinical Medicine and Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
| | - Tzu-Ting Kuo
- Institute of Clinical Medicine and Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
- Division of Cardiovascular Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei 112201, Taiwan
| | - Jo-Nan Liao
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112201, Taiwan; (P.-F.H.); (Y.-J.L.); (J.-N.L.); (Y.-Y.C.); (S.-A.C.)
- Institute of Clinical Medicine and Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
| | - Yun-Yu Chen
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112201, Taiwan; (P.-F.H.); (Y.-J.L.); (J.-N.L.); (Y.-Y.C.); (S.-A.C.)
- Institute of Epidemiology and Preventive Medicine College of Public Health, National Taiwan University, Taipei 100025, Taiwan
| | - Chih-Hsin Pan
- Institute of Forensic Medicine, Ministry of Justice, New Taipei City 235016, Taiwan; (C.-H.P.); (K.-P.S.)
| | - Kai-Ping Shaw
- Institute of Forensic Medicine, Ministry of Justice, New Taipei City 235016, Taiwan; (C.-H.P.); (K.-P.S.)
| | - Shih-Ann Chen
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112201, Taiwan; (P.-F.H.); (Y.-J.L.); (J.-N.L.); (Y.-Y.C.); (S.-A.C.)
- Institute of Clinical Medicine and Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
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Kant S, Krusche CA, Gaertner A, Milting H, Leube RE. Loss of plakoglobin immunoreactivity in intercalated discs in arrhythmogenic right ventricular cardiomyopathy: protein mislocalization versus epitope masking. Cardiovasc Res 2015; 109:260-71. [PMID: 26676851 DOI: 10.1093/cvr/cvv270] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 11/27/2015] [Indexed: 01/13/2023] Open
Abstract
AIMS To examine the relevance and cause of reduced plakoglobin IF in intercalated discs for arrhythmogenic right ventricular cardiomyopathy (ARVC) and ARVC-like disease in mouse and human. METHODS AND RESULTS Normalized semi-quantitative IF measurements were performed in a standardized format in desmoglein 2-mutant mice with an ARVC-like phenotype (n = 6) and in cardiac biopsies from humans with ARVC and non-ARVC heart disease (n = 10). Reduced plakoglobin staining was detectable in ARVC only with one antibody directed against a defined epitope but not with three other antibodies reacting with different epitopes of plakoglobin. CONCLUSIONS Reduced plakoglobin staining in intercalated discs of heart tissue from human ARVC patients and in a murine ARVC model is caused by alterations in epitope accessibility and not by protein relocalization.
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Affiliation(s)
- Sebastian Kant
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, Aachen 52074, Germany
| | - Claudia A Krusche
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, Aachen 52074, Germany
| | - Anna Gaertner
- Herz- und Diabeteszentrum NRW, Klinik für Thorax- und Kardiovaskularchirurgie, Erich und Hanna Klessmann-Institut für Kardiovaskuläre Forschung und Entwicklung, Bad Oeynhausen, Germany
| | - Hendrik Milting
- Herz- und Diabeteszentrum NRW, Klinik für Thorax- und Kardiovaskularchirurgie, Erich und Hanna Klessmann-Institut für Kardiovaskuläre Forschung und Entwicklung, Bad Oeynhausen, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, Aachen 52074, Germany
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Abstract
Arrhythmogenic cardiomyopathy (ACM) is a primary myocardial disease. It is characterized by frequent ventricular arrhythmias and increased risk of sudden cardiac death typically arising as an early manifestation before the onset of significant myocardial remodelling. Myocardial degeneration, often confined to the right ventricular free wall, with replacement by fibrofatty scar tissue, develops in many patients. ACM is a familial disease but genetic penetrance can be low and disease expression is highly variable. Inflammation might promote disease progression. It also appears that exercise increases disease penetrance and accelerates its development. More than 60% of probands harbour mutations in genes that encode desmosomal proteins, which has raised the possibility that defective cell-cell adhesion might play a role in disease pathogenesis. Recent advances have implicated changes in the canonical wingless-type mouse mammary tumour virus integration site (Wnt)/β-catenin and Hippo signalling pathways and defects in forwarding trafficking of ion channels and other proteins to the intercalated disk in cardiac myocytes. In this review we summarize the current understanding of the pathogenesis of ACM and highlight future research directions.
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Affiliation(s)
- Angeliki Asimaki
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Andre G Kleber
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey E Saffitz
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
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