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Zhu P, Li J, Yan F, Islam S, Lin X, Xu X. Allelic heterogeneity of TTNtv dilated cardiomyopathy can be modeled in adult zebrafish. JCI Insight 2024; 9:e175501. [PMID: 38412038 PMCID: PMC11128207 DOI: 10.1172/jci.insight.175501] [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: 09/07/2023] [Accepted: 02/21/2024] [Indexed: 02/29/2024] Open
Abstract
Allelic heterogeneity (AH) has been noted in truncational TTN-associated (TTNtv-associated) dilated cardiomyopathy (DCM); i.e., mutations affecting A-band-encoding exons are pathogenic, but those affecting Z-disc-encoding exons are likely benign. The lack of an in vivo animal model that recapitulates AH hinders the deciphering of the underlying mechanism. Here, we explored zebrafish as a candidate vertebrate model by phenotyping a collection of zebrafish ttntv alleles. We noted that cardiac function and sarcomere structure were more severely disrupted in ttntv-A than in ttntv-Z homozygous embryos. Consistently, cardiomyopathy-like phenotypes were present in ttntv-A but not ttntv-Z adult heterozygous mutants. The phenotypes observed in ttntv-A alleles were recapitulated in null mutants with the full titin-encoding sequences removed. Defective autophagic flux, largely due to impaired autophagosome-lysosome fusion, was also noted only in ttntv-A but not in ttntv-Z models. Moreover, we found that genetic manipulation of ulk1a restored autophagy flux and rescued cardiac dysfunction in ttntv-A animals. Together, our findings presented adult zebrafish as an in vivo animal model for studying AH in TTNtv DCM, demonstrated TTN loss of function is sufficient to trigger ttntv DCM in zebrafish, and uncovered ulk1a as a potential therapeutic target gene for TTNtv DCM.
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Affiliation(s)
- Ping Zhu
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Jiarong Li
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Cardiovascular Surgery, Second Xiangya Hospital, Central South University, Changsha, China
| | - Feixiang Yan
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Shahidul Islam
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
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2
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Dai Y, Ignatyeva N, Xu H, Wali R, Toischer K, Brandenburg S, Lenz C, Pronto J, Fakuade FE, Sossalla S, Zeisberg EM, Janshoff A, Kutschka I, Voigt N, Urlaub H, Rasmussen TB, Mogensen J, Lehnart SE, Hasenfuss G, Ebert A. An Alternative Mechanism of Subcellular Iron Uptake Deficiency in Cardiomyocytes. Circ Res 2023; 133:e19-e46. [PMID: 37313752 DOI: 10.1161/circresaha.122.321157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 05/26/2023] [Indexed: 06/15/2023]
Abstract
BACKGROUND Systemic defects in intestinal iron absorption, circulation, and retention cause iron deficiency in 50% of patients with heart failure. Defective subcellular iron uptake mechanisms that are independent of systemic absorption are incompletely understood. The main intracellular route for iron uptake in cardiomyocytes is clathrin-mediated endocytosis. METHODS We investigated subcellular iron uptake mechanisms in patient-derived and CRISPR/Cas-edited induced pluripotent stem cell-derived cardiomyocytes as well as patient-derived heart tissue. We used an integrated platform of DIA-MA (mass spectrometry data-independent acquisition)-based proteomics and signaling pathway interrogation. We employed a genetic induced pluripotent stem cell model of 2 inherited mutations (TnT [troponin T]-R141W and TPM1 [tropomyosin 1]-L185F) that lead to dilated cardiomyopathy (DCM), a frequent cause of heart failure, to study the underlying molecular dysfunctions of DCM mutations. RESULTS We identified a druggable molecular pathomechanism of impaired subcellular iron deficiency that is independent of systemic iron metabolism. Clathrin-mediated endocytosis defects as well as impaired endosome distribution and cargo transfer were identified as a basis for subcellular iron deficiency in DCM-induced pluripotent stem cell-derived cardiomyocytes. The clathrin-mediated endocytosis defects were also confirmed in the hearts of patients with DCM with end-stage heart failure. Correction of the TPM1-L185F mutation in DCM patient-derived induced pluripotent stem cells, treatment with a peptide, Rho activator II, or iron supplementation rescued the molecular disease pathway and recovered contractility. Phenocopying the effects of the TPM1-L185F mutation into WT induced pluripotent stem cell-derived cardiomyocytes could be ameliorated by iron supplementation. CONCLUSIONS Our findings suggest that impaired endocytosis and cargo transport resulting in subcellular iron deficiency could be a relevant pathomechanism for patients with DCM carrying inherited mutations. Insight into this molecular mechanism may contribute to the development of treatment strategies and risk management in heart failure.
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Affiliation(s)
- Yuanyuan Dai
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Nadezda Ignatyeva
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Hang Xu
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Ruheen Wali
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Karl Toischer
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
| | - Sören Brandenburg
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
| | - Christof Lenz
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Department of Clinical Chemistry, University Medical Center Goettingen, (C.L., H.U.), University of Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Goettingen (C.L., H.U.)
| | - Julius Pronto
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Institute of Pharmacology and Toxicology, University Medical Center Goettingen, (J.P., F.E.F., N.V.), University of Goettingen, Germany
| | - Funsho E Fakuade
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Institute of Pharmacology and Toxicology, University Medical Center Goettingen, (J.P., F.E.F., N.V.), University of Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
| | - Samuel Sossalla
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
- Department for Internal Medicine II, University Medical Center Regensburg (S.S.)
| | - Elisabeth M Zeisberg
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Andreas Janshoff
- Institute for Physical Chemistry (A.J.), University of Goettingen, Germany
| | - Ingo Kutschka
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Göttingen (I.K.)
| | - Niels Voigt
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Institute of Pharmacology and Toxicology, University Medical Center Goettingen, (J.P., F.E.F., N.V.), University of Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
| | - Henning Urlaub
- Department of Clinical Chemistry, University Medical Center Goettingen, (C.L., H.U.), University of Goettingen, Germany
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Goettingen (C.L., H.U.)
| | | | - Jens Mogensen
- Department of Cardiology, Aalborg University Hospital, Denmark (J.M.)
| | - Stephan E Lehnart
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
| | - Gerd Hasenfuss
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
| | - Antje Ebert
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
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Khalilimeybodi A, Riaz M, Campbell SG, Omens JH, McCulloch AD, Qyang Y, Saucerman JJ. Signaling network model of cardiomyocyte morphological changes in familial cardiomyopathy. J Mol Cell Cardiol 2023; 174:1-14. [PMID: 36370475 PMCID: PMC10230857 DOI: 10.1016/j.yjmcc.2022.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 08/26/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022]
Abstract
Familial cardiomyopathy is a precursor of heart failure and sudden cardiac death. Over the past several decades, researchers have discovered numerous gene mutations primarily in sarcomeric and cytoskeletal proteins causing two different disease phenotypes: hypertrophic (HCM) and dilated (DCM) cardiomyopathies. However, molecular mechanisms linking genotype to phenotype remain unclear. Here, we employ a systems approach by integrating experimental findings from preclinical studies (e.g., murine data) into a cohesive signaling network to scrutinize genotype to phenotype mechanisms. We developed an HCM/DCM signaling network model utilizing a logic-based differential equations approach and evaluated model performance in predicting experimental data from four contexts (HCM, DCM, pressure overload, and volume overload). The model has an overall prediction accuracy of 83.8%, with higher accuracy in the HCM context (90%) than DCM (75%). Global sensitivity analysis identifies key signaling reactions, with calcium-mediated myofilament force development and calcium-calmodulin kinase signaling ranking the highest. A structural revision analysis indicates potential missing interactions that primarily control calcium regulatory proteins, increasing model prediction accuracy. Combination pharmacotherapy analysis suggests that downregulation of signaling components such as calcium, titin and its associated proteins, growth factor receptors, ERK1/2, and PI3K-AKT could inhibit myocyte growth in HCM. In experiments with patient-specific iPSC-derived cardiomyocytes (MLP-W4R;MYH7-R723C iPSC-CMs), combined inhibition of ERK1/2 and PI3K-AKT rescued the HCM phenotype, as predicted by the model. In DCM, PI3K-AKT-NFAT downregulation combined with upregulation of Ras/ERK1/2 or titin or Gq protein could ameliorate cardiomyocyte morphology. The model results suggest that HCM mutations that increase active force through elevated calcium sensitivity could increase ERK activity and decrease eccentricity through parallel growth factors, Gq-mediated, and titin pathways. Moreover, the model simulated the influence of existing medications on cardiac growth in HCM and DCM contexts. This HCM/DCM signaling model demonstrates utility in investigating genotype to phenotype mechanisms in familial cardiomyopathy.
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Affiliation(s)
- Ali Khalilimeybodi
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States of America
| | - Muhammad Riaz
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jeffrey H Omens
- Departments of Bioengineering and Medicine, University of California, San Diego, La Jolla, CA, United States of America
| | - Andrew D McCulloch
- Departments of Bioengineering and Medicine, University of California, San Diego, La Jolla, CA, United States of America
| | - Yibing Qyang
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, New Haven, CT, United States of America; Department of Pathology, Yale University, New Haven, CT, United States of America; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, United States of America
| | - Jeffrey J Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States of America; Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, United States of America.
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Gladding PA, Cooper M, Young R, Loader S, Smith K, Zarate E, Green S, Villas Boas SG, Shepherd P, Kakadiya P, Thorstensen E, Keven C, Coe M, Jüllig M, Zhang E, Schlegel TT. Metabolomics and a Breath Sensor Identify Acetone as a Biomarker for Heart Failure. Biomolecules 2022; 13:biom13010013. [PMID: 36671398 PMCID: PMC9856097 DOI: 10.3390/biom13010013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Multi-omics delivers more biological insight than targeted investigations. We applied multi-omics to patients with heart failure with reduced ejection fraction (HFrEF). METHODS 46 patients with HFrEF and 20 controls underwent metabolomic profiling, including liquid/gas chromatography mass spectrometry (LC-MS/GC-MS) and solid-phase microextraction (SPME) volatilomics in plasma and urine. HFrEF was defined using left ventricular global longitudinal strain, ejection fraction and NTproBNP. A consumer breath acetone (BrACE) sensor validated results in n = 73. RESULTS 28 metabolites were identified by GCMS, 35 by LCMS and 4 volatiles by SPME in plasma and urine. Alanine, aspartate and glutamate, citric acid cycle, arginine biosynthesis, glyoxylate and dicarboxylate metabolism were altered in HFrEF. Plasma acetone correlated with NT-proBNP (r = 0.59, 95% CI 0.4 to 0.7), 2-oxovaleric and cis-aconitic acid, involved with ketone metabolism and mitochondrial energetics. BrACE > 1.5 ppm discriminated HF from other cardiac pathology (AUC 0.8, 95% CI 0.61 to 0.92, p < 0.0001). CONCLUSION Breath acetone discriminated HFrEF from other cardiac pathology using a consumer sensor, but was not cardiac specific.
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Affiliation(s)
- Patrick A. Gladding
- Cardiology Department, Waitemata District Health Board, Auckland 0620, New Zealand; (M.C.); (R.Y.); (S.L.)
- Auckland Bioengineering Institute, Auckland 1142, New Zealand
- Correspondence:
| | - Maxine Cooper
- Cardiology Department, Waitemata District Health Board, Auckland 0620, New Zealand; (M.C.); (R.Y.); (S.L.)
| | - Renee Young
- Cardiology Department, Waitemata District Health Board, Auckland 0620, New Zealand; (M.C.); (R.Y.); (S.L.)
| | - Suzanne Loader
- Cardiology Department, Waitemata District Health Board, Auckland 0620, New Zealand; (M.C.); (R.Y.); (S.L.)
| | - Kevin Smith
- Clinical Laboratory, Waitemata District Health Board, Auckland 0622, New Zealand;
| | - Erica Zarate
- School of Biological Science, University of Auckland, Auckland 1010, New Zealand; (E.Z.); (S.G.); (S.G.V.B.)
| | - Saras Green
- School of Biological Science, University of Auckland, Auckland 1010, New Zealand; (E.Z.); (S.G.); (S.G.V.B.)
| | - Silas G. Villas Boas
- School of Biological Science, University of Auckland, Auckland 1010, New Zealand; (E.Z.); (S.G.); (S.G.V.B.)
| | - Phillip Shepherd
- Grafton Genomics Ltd., Liggins Institute, University of Auckland, Auckland 1010, New Zealand; (P.S.); (P.K.)
| | - Purvi Kakadiya
- Grafton Genomics Ltd., Liggins Institute, University of Auckland, Auckland 1010, New Zealand; (P.S.); (P.K.)
| | - Eric Thorstensen
- Liggins Institute, University of Auckland, Auckland 1010, New Zealand; (E.T.); (C.K.); (M.C.)
| | - Christine Keven
- Liggins Institute, University of Auckland, Auckland 1010, New Zealand; (E.T.); (C.K.); (M.C.)
| | - Margaret Coe
- Liggins Institute, University of Auckland, Auckland 1010, New Zealand; (E.T.); (C.K.); (M.C.)
| | - Mia Jüllig
- Paper Dog Ltd., Waiheke Island, Auckland 1081, New Zealand;
| | - Edmond Zhang
- Precision Driven Health Initiative, Auckland 1021, New Zealand;
| | - Todd T. Schlegel
- Karolinska Institutet, 17177 Stockholm, Sweden;
- Nicollier-Schlegel Sàrl, 1270 Trélex, Switzerland
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Abstract
PURPOSE OF REVIEW Truncating TTN variants (TTNtv) are the most common genetic cause of dilated cardiomyopathy (DCM), but the underlying mechanisms are incompletely understood and effective therapeutic strategies are lacking. Here we review recent data that shed new light on the functional consequences of TTNtv and how these effects may vary with mutation location. RECENT FINDINGS Whether TTNtv act by haploinsufficiency or dominant negative effects has been hotly debated. New evidence now implicates both mechanisms in TTNtv-related DCM, showing reduced titin content and persistent truncated titin that may be incorporated into protein aggregates. The extent to which aggregate formation and protein quality control defects differ with TTNtv location and contribute to contractile dysfunction is unresolved. TTNtv-associated DCM has a complex etiology that involves varying combinations of wild-type titin deficiency and dominant negative effects of truncated mutant titin. Therapeutic strategies to improve protein handling may be beneficial in some cases.
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Implication of a novel truncating mutation in titin as a cause of autosomal dominant left ventricular noncompaction. J Geriatr Cardiol 2022; 19:301-314. [PMID: 35572216 PMCID: PMC9068586 DOI: 10.11909/j.issn.1671-5411.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Mutation in the titin gene (TTN) in left ventricular noncompaction (LVNC) has been reported with a highly heterogeneous prevalence, and the molecular mechanisms underlying the pathogenesis of TTN gene mutation are uncharacterized. In the present study, we identified a novel TTN mutation in a pedigree with LVNC and investigated the potential pathogenic mechanism by functional studies. METHODS The whole-genome sequencing with linkage analysis was performed in a 3-generation family affected by autosomal dominant LVNC cardiomyopathy. The clustered regularly interspaced short palindromic repeats associated protein 9 (CRISPR/Cas9) technology was used to establish novel truncating mutation in TTN in a rat cardiomyoblast H9C2 cell line in vitro, in which functional studies were carried out and characterized in comparison to its wild-type counterpart. RESULTS A novel truncating mutation TTN p. R2021X was identified as the only plausible disease-causing variant that segregated with disease among the five surviving affected individuals, with an interrogation of the entire genome excluding other potential causes. Quantitative reverse transcription-polymerase chain reaction and cellular immunofluorescence supported a haploinsufficient disease mechanism in titin truncation mutation cardiomyocytes. Further functional studies suggested mitochondrial abnormities in the presence of mutation, including decreased oxygen consumption rate, reduced adenosine triphosphate production, impaired activity of electron translation chain, and abnormal mitochondrial structure on electron microscopy. Impaired autophagy under electron microscopy accompanied with activation of the Akt-mTORC1 signaling pathway was observed in TTN p. R2021X truncation mutation cardiomyocytes. CONCLUSIONS The TTN p. R2021X mutation has a function in the cause of a highly penetrant familial LVNC. These findings expand the spectrum of titin's roles in cardiomyopathies and provide novel insight into the molecular basis of titin-truncating variants-associated LVNC.
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Zou S, Ye J, Hu S, Wei Y, Xu J. Mutations in the TTN Gene are a Prognostic Factor for Patients with Lung Squamous Cell Carcinomas. Int J Gen Med 2022; 15:19-31. [PMID: 35018111 PMCID: PMC8742622 DOI: 10.2147/ijgm.s343259] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/20/2021] [Indexed: 01/04/2023] Open
Abstract
Purpose To analyze the relationship between titin (TTN) mutation gene and tumor mutational burden (TMB) and the with prognosis of lung squamous cell carcinomas (LUSC), and to explore the feasibility of TTN as a potential prognostic marker of for LUSC. Methods We analyzed the somatic mutation landscape of LUSC samples using datasets obtained from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases. Sequence data were divided into wild and mutant groups, and differences in TMB values between the groups compared using a Mann–Whitney U-test. The Kaplan Meier method was used to analyze the correlation between TTN mutation and LUSC prognosis, whereas CIBERSORT algorithm was used to calculate the degree of relative enrichment degree of among tumor-infiltrating lymphocytes in LUSC. Results Analysis of both datasets revealed high mutations in the TTN gene, with mutants exhibiting a significantly higher TMB value relative to the wild-type (P < 0.001). Prognosis of the TTN mutant group in LUSC was significantly better than that of wild-type (P = 0.009). Kaplan Meier curves showed that TTN mutation may be an independent prognostic factor in LUSC patients (HR: 0.64, 95% CI 0.48–0.85, P = 0.001), while GSEA analysis revealed that TTN mutation plays a potential role in the development of LUSC. Finally, analysis of LUSC immune microenvironment revealed that TTN mutation was significantly associated with enrichment of macrophages M1 (p < 0.05). Conclusion TTN mutation is associated with TMB, and is positively correlated with prognosis of LUSC. Therefore, this mutation may serve as a potential prognostic indicator of LUSC.
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Affiliation(s)
- Sheng Zou
- Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, People's Republic of China
| | - Jiayue Ye
- Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, People's Republic of China
| | - Sheng Hu
- Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, People's Republic of China
| | - Yiping Wei
- Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, People's Republic of China
| | - Jianjun Xu
- Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, People's Republic of China
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8
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McAfee Q, Chen CY, Yang Y, Caporizzo MA, Morley M, Babu A, Jeong S, Brandimarto J, Bedi KC, Flam E, Cesare J, Cappola TP, Margulies K, Prosser B, Arany Z. Truncated titin proteins in dilated cardiomyopathy. Sci Transl Med 2021; 13:eabd7287. [PMID: 34731015 PMCID: PMC9236909 DOI: 10.1126/scitranslmed.abd7287] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Truncating variants in TTN (TTNtvs) are the most common known cause of nonischemic dilated cardiomyopathy (DCM), but how TTNtvs cause disease has remained controversial. Efforts to detect truncated titin proteins in affected human DCM hearts have failed, suggesting that disease is caused by haploinsufficiency, but reduced amounts of titin protein have not yet been demonstrated. Here, we leveraged a collection of 184 explanted posttransplant DCM hearts to show, using specialized electrophoretic gels, Western blotting, allelic phasing, and unbiased proteomics, that truncated titin proteins can quantitatively be detected in human DCM hearts. The sizes of truncated proteins corresponded to that predicted by their respective TTNtvs; the truncated proteins were encoded by the TTNtv-bearing allele; and no degradation fragments from protein encoded by either allele were detectable. In parallel, full-length titin was less abundant in TTNtv+ than in TTNtv− DCM hearts. Disease severity or need for transplantation did not correlate with TTNtv location. Transcriptomic profiling revealed few differences in splicing or allelic imbalance of the TTN transcript between TTNtv+ and TTNtv− DCM hearts. Studies with isolated human adult cardiomyocytes revealed no defects in contractility in cells from TTNtv+ compared to TTNtv− DCM hearts. Together, these data demonstrate the presence of truncated titin protein in human TTNtv+ DCM, show reduced amounts of full-length titin protein in TTNtv+ DCM hearts, and support combined dominant-negative and haploinsufficiency contributions to disease.
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Affiliation(s)
- Quentin McAfee
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Yifan Yang
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Matthew A. Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Michael Morley
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Apoorva Babu
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Sunhye Jeong
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Jeffrey Brandimarto
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Kenneth C. Bedi
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Emily Flam
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Joseph Cesare
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Thomas P. Cappola
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Kenneth Margulies
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Benjamin Prosser
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Zolt Arany
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
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9
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Müller E, Salcan S, Bongardt S, Barbosa DM, Krüger M, Kötter S. E3-ligase knock down revealed differential titin degradation by autopagy and the ubiquitin proteasome system. Sci Rep 2021; 11:21134. [PMID: 34702928 PMCID: PMC8548520 DOI: 10.1038/s41598-021-00618-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/30/2021] [Indexed: 01/09/2023] Open
Abstract
The sarcomere protein titin is a major determinant of cardiomyocyte stiffness and ventricular distensibility. The constant mechanical stress on titin requires well-controlled protein quality control, the exact mechanisms of which have not yet been fully elucidated. Here, we analyzed E3-ligases potentially responsible for cardiac titin ubiquitination and specifically studied the involvement of the autophagosomal system in titin degradation. Pharmacological inhibition of autophagy and the proteasome in cultured primary rat cardiomyocytes significantly elevated titin ubiquitination and increased titin degradation. Using in-vitro pull down assays we identified binding of E3-ligases MuRF1-3, CHIP and Fbx32 to several titin domains. Immunofluorescence analysis showed sarcomeric localization of the E3-ligases. siRNA-mediated knock-down of the E3-ligases MuRF-1, -3 and a combination of CHIP/Fbx32 significantly reduced autophagy-related titin ubiquitination, whereas knock-down of MuRF-2 and -3 reduced proteasome-related titin ubiquitination. We demonstrated that the proteasomal and the autophagosomal-lysosomal system participate in degradation of the titin filament. We found that ubiquitination and degradation of titin are partially regulated by E3-ligases of the MuRF family. We further identified CHIP and Fbx32 as E3-ligases involved in titin ubiquitination.
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Affiliation(s)
- Erik Müller
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Senem Salcan
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Sabine Bongardt
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - David Monteiro Barbosa
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Martina Krüger
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Sebastian Kötter
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany.
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10
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Collins HE, Kane MS, Litovsky SH, Darley-Usmar VM, Young ME, Chatham JC, Zhang J. Mitochondrial Morphology and Mitophagy in Heart Diseases: Qualitative and Quantitative Analyses Using Transmission Electron Microscopy. FRONTIERS IN AGING 2021; 2:670267. [PMID: 35822027 PMCID: PMC9261312 DOI: 10.3389/fragi.2021.670267] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 03/26/2021] [Indexed: 01/21/2023]
Abstract
Transmission electron microscopy (TEM) has long been an important technique, capable of high degree resolution and visualization of subcellular structures and organization. Over the last 20 years, TEM has gained popularity in the cardiovascular field to visualize changes at the nanometer scale in cardiac ultrastructure during cardiovascular development, aging, and a broad range of pathologies. Recently, the cardiovascular TEM enabled the studying of several signaling processes impacting mitochondrial function, such as mitochondrial fission/fusion, autophagy, mitophagy, lysosomal degradation, and lipophagy. The goals of this review are to provide an overview of the current usage of TEM to study cardiac ultrastructural changes; to understand how TEM aided the visualization of mitochondria, autophagy, and mitophagy under normal and cardiovascular disease conditions; and to discuss the overall advantages and disadvantages of TEM and potential future capabilities and advancements in the field.
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Affiliation(s)
- Helen E. Collins
- Division of Environmental Medicine, Department of Medicine, University of Louisville, KY, United States
| | - Mariame Selma Kane
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Silvio H. Litovsky
- Division of Anatomic Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Victor M. Darley-Usmar
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Martin E. Young
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - John C. Chatham
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jianhua Zhang
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
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11
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Santiago CF, Huttner IG, Fatkin D. Mechanisms of TTNtv-Related Dilated Cardiomyopathy: Insights from Zebrafish Models. J Cardiovasc Dev Dis 2021; 8:jcdd8020010. [PMID: 33504111 PMCID: PMC7912658 DOI: 10.3390/jcdd8020010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/15/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a common heart muscle disorder characterized by ventricular dilation and contractile dysfunction that is associated with significant morbidity and mortality. New insights into disease mechanisms and strategies for treatment and prevention are urgently needed. Truncating variants in the TTN gene, which encodes the giant sarcomeric protein titin (TTNtv), are the most common genetic cause of DCM, but exactly how TTNtv promote cardiomyocyte dysfunction is not known. Although rodent models have been widely used to investigate titin biology, they have had limited utility for TTNtv-related DCM. In recent years, zebrafish (Danio rerio) have emerged as a powerful alternative model system for studying titin function in the healthy and diseased heart. Optically transparent embryonic zebrafish models have demonstrated key roles of titin in sarcomere assembly and cardiac development. The increasing availability of sophisticated imaging tools for assessment of heart function in adult zebrafish has revolutionized the field and opened new opportunities for modelling human genetic disorders. Genetically modified zebrafish that carry a human A-band TTNtv have now been generated and shown to spontaneously develop DCM with age. This zebrafish model will be a valuable resource for elucidating the phenotype modifying effects of genetic and environmental factors, and for exploring new drug therapies.
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Affiliation(s)
- Celine F. Santiago
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Inken G. Huttner
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Diane Fatkin
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
- Cardiology Department, St. Vincent’s Hospital, Darlinghurst, NSW 2010, Australia
- Correspondence:
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12
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Sciarretta S, Forte M, Castoldi F, Frati G, Versaci F, Sadoshima J, Kroemer G, Maiuri MC. Caloric restriction mimetics for the treatment of cardiovascular diseases. Cardiovasc Res 2020; 117:1434-1449. [PMID: 33098415 DOI: 10.1093/cvr/cvaa297] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/09/2020] [Indexed: 12/25/2022] Open
Abstract
Caloric restriction mimetics (CRMs) are emerging as potential therapeutic agents for the treatment of cardiovascular diseases. CRMs include natural and synthetic compounds able to inhibit protein acetyltransferases, to interfere with acetyl coenzyme A biosynthesis, or to activate (de)acetyltransferase proteins. These modifications mimic the effects of caloric restriction, which is associated with the activation of autophagy. Previous evidence demonstrated the ability of CRMs to ameliorate cardiac function and reduce cardiac hypertrophy and maladaptive remodelling in animal models of ageing, mechanical overload, chronic myocardial ischaemia, and in genetic and metabolic cardiomyopathies. In addition, CRMs were found to reduce acute ischaemia-reperfusion injury. In many cases, these beneficial effects of CRMs appeared to be mediated by autophagy activation. In the present review, we discuss the relevant literature about the role of different CRMs in animal models of cardiac diseases, emphasizing the molecular mechanisms underlying the beneficial effects of these compounds and their potential future clinical application.
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Affiliation(s)
- Sebastiano Sciarretta
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 40100 Latina, Italy.,Department of AngioCardioNeurology, IRCCS Neuromed, Pozzilli (IS), Italy
| | - Maurizio Forte
- Department of AngioCardioNeurology, IRCCS Neuromed, Pozzilli (IS), Italy
| | - Francesca Castoldi
- Centre de Recherche des Cordeliers, Team "Metabolism, Cancer & Immunity", INSERM UMRS1138, Université de Paris, Sorbonne Université, 75006 Paris, France.,Cell Biology and Metabolomics platforms, Gustave Roussy Cancer Campus, 94805 Villejuif, France
| | - Giacomo Frati
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 40100 Latina, Italy.,Department of AngioCardioNeurology, IRCCS Neuromed, Pozzilli (IS), Italy
| | - Francesco Versaci
- Division of Cardiology, S. Maria Goretti Hospital, 04100 Latina, Italy
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, 185 South Orange Avenue, G-609, Newark, NJ 07103, USA
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Team "Metabolism, Cancer & Immunity", INSERM UMRS1138, Université de Paris, Sorbonne Université, 75006 Paris, France.,Cell Biology and Metabolomics platforms, Gustave Roussy Cancer Campus, 94805 Villejuif, France.,Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, 75015 Paris, France.,Suzhou Institute for Systems Medicine, Chinese Academy of Sciences, Suzhou Jiangsu 215163, China.,Department of Women's and Children's Health, Karolinska Institute, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Maria Chiara Maiuri
- Centre de Recherche des Cordeliers, Team "Metabolism, Cancer & Immunity", INSERM UMRS1138, Université de Paris, Sorbonne Université, 75006 Paris, France.,Cell Biology and Metabolomics platforms, Gustave Roussy Cancer Campus, 94805 Villejuif, France
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13
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Modifications of Titin Contribute to the Progression of Cardiomyopathy and Represent a Therapeutic Target for Treatment of Heart Failure. J Clin Med 2020; 9:jcm9092770. [PMID: 32859027 PMCID: PMC7564493 DOI: 10.3390/jcm9092770] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Titin is the largest human protein and an essential component of the cardiac sarcomere. With multiple immunoglobulin(Ig)-like domains that serve as molecular springs, titin contributes significantly to the passive tension, systolic function, and diastolic function of the heart. Mutations leading to early termination of titin are the most common genetic cause of dilated cardiomyopathy. Modifications of titin, which change protein length, and relative stiffness affect resting tension of the ventricle and are associated with acquired forms of heart failure. Transcriptional and post-translational changes that increase titin’s length and extensibility, making the sarcomere longer and softer, are associated with systolic dysfunction and left ventricular dilation. Modifications of titin that decrease its length and extensibility, making the sarcomere shorter and stiffer, are associated with diastolic dysfunction in animal models. There has been significant progress in understanding the mechanisms by which titin is modified. As molecular pathways that modify titin’s mechanical properties are elucidated, they represent therapeutic targets for treatment of both systolic and diastolic dysfunction. In this article, we review titin’s contribution to normal cardiac physiology, the pathophysiology of titin truncation variations leading to dilated cardiomyopathy, and transcriptional and post-translational modifications of titin. Emphasis is on how modification of titin can be utilized as a therapeutic target for treatment of heart failure.
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14
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Yang M, Zhang Y, Ren J. Acetylation in cardiovascular diseases: Molecular mechanisms and clinical implications. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165836. [PMID: 32413386 DOI: 10.1016/j.bbadis.2020.165836] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023]
Abstract
Acetylation belongs to a class of post-translational modification (PTM) processes that epigenetically regulate gene expression and gene transcriptional activity. Reversible histone acetylation on lysine residues governs the interactions between DNA and histones to mediate chromatin remodeling and gene transcription. Non-histone protein acetylation complicates cellular function whereas acetylation of key mitochondrial enzymes regulates bioenergetic metabolism. Acetylation and deacetylation of functional proteins are essential to the delicated homeostatic regulation of embryonic development, postnatal maturation, cardiomyocyte differentiation, cardiac remodeling and onset of various cardiovascular diseases including obesity, diabetes mellitus, cardiometabolic diseases, ischemia-reperfusion injury, cardiac remodeling, hypertension, and arrhythmias. Histone acetyltransferase (HATs) and histone deacetylases (HDACs) are essential enzymes mainly responsible for the regulation of lysine acetylation levels, thus providing possible drugable targets for therapeutic interventions in the management of cardiovascular diseases.
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Affiliation(s)
- Mingjie Yang
- Department of Cardiology and Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 210032, China
| | - Yingmei Zhang
- Department of Cardiology and Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 210032, China.
| | - Jun Ren
- Department of Cardiology and Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 210032, China.
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15
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Sacchetto C, Sequeira V, Bertero E, Dudek J, Maack C, Calore M. Metabolic Alterations in Inherited Cardiomyopathies. J Clin Med 2019; 8:E2195. [PMID: 31842377 PMCID: PMC6947282 DOI: 10.3390/jcm8122195] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 12/12/2022] Open
Abstract
The normal function of the heart relies on a series of complex metabolic processes orchestrating the proper generation and use of energy. In this context, mitochondria serve a crucial role as a platform for energy transduction by supplying ATP to the varying demand of cardiomyocytes, involving an intricate network of pathways regulating the metabolic flux of substrates. The failure of these processes results in structural and functional deficiencies of the cardiac muscle, including inherited cardiomyopathies. These genetic diseases are characterized by cardiac structural and functional anomalies in the absence of abnormal conditions that can explain the observed myocardial abnormality, and are frequently associated with heart failure. Since their original description, major advances have been achieved in the genetic and phenotype knowledge, highlighting the involvement of metabolic abnormalities in their pathogenesis. This review provides a brief overview of the role of mitochondria in the energy metabolism in the heart and focuses on metabolic abnormalities, mitochondrial dysfunction, and storage diseases associated with inherited cardiomyopathies.
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Affiliation(s)
- Claudia Sacchetto
- IMAiA—Institute for Molecular Biology and RNA Technology, Faculty of Health, Universiteitssingel 50, 6229ER Maastricht, The Netherlands;
- Medicine and Life Sciences, Faculty of Science and Engineering, Universiteitssingel 50, 6229ER Maastricht, The Netherlands
- Department of Biology, University of Padova, via Ugo Bassi 58B, 35121 Padova, Italy
| | - Vasco Sequeira
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Edoardo Bertero
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Jan Dudek
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Christoph Maack
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Martina Calore
- IMAiA—Institute for Molecular Biology and RNA Technology, Faculty of Health, Universiteitssingel 50, 6229ER Maastricht, The Netherlands;
- Medicine and Life Sciences, Faculty of Science and Engineering, Universiteitssingel 50, 6229ER Maastricht, The Netherlands
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16
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Ding Y, Dvornikov AV, Ma X, Zhang H, Wang Y, Lowerison M, Packard RR, Wang L, Chen J, Zhang Y, Hsiai T, Lin X, Xu X. Haploinsufficiency of mechanistic target of rapamycin ameliorates bag3 cardiomyopathy in adult zebrafish. Dis Model Mech 2019; 12:dmm040154. [PMID: 31492659 PMCID: PMC6826022 DOI: 10.1242/dmm.040154] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/28/2019] [Indexed: 12/14/2022] Open
Abstract
The adult zebrafish is an emerging vertebrate model for studying human cardiomyopathies; however, whether the simple zebrafish heart can model different subtypes of cardiomyopathies, such as dilated cardiomyopathy (DCM), remains elusive. Here, we generated and characterized an inherited DCM model in adult zebrafish and used this model to search for therapeutic strategies. We employed transcription activator-like effector nuclease (TALEN) genome editing technology to generate frame-shift mutants for the zebrafish ortholog of human BCL2-associated athanogene 3 (BAG3), an established DCM-causative gene. As in mammals, the zebrafish bag3 homozygous mutant (bag3e2/e2 ) exhibited aberrant proteostasis, as indicated by impaired autophagy flux and elevated ubiquitinated protein aggregation. Through comprehensive phenotyping analysis of the mutant, we identified phenotypic traits that resembled DCM phenotypes in mammals, including cardiac chamber enlargement, reduced ejection fraction characterized by increased end-systolic volume/body weight (ESV/BW), and reduced contractile myofibril activation kinetics. Nonbiased transcriptome analysis identified the hyperactivation of the mechanistic target of rapamycin (mTOR) signaling in bag3e2/e2 mutant hearts. Further genetic studies showed that mtorxu015/+ , an mTOR haploinsufficiency mutant, repaired abnormal proteostasis, improved cardiac function and rescued the survival of the bag3e2/e2 mutant. This study established the bag3e2/e2 mutant as a DCM model in adult zebrafish and suggested mtor as a candidate therapeutic target gene for BAG3 cardiomyopathy.
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Affiliation(s)
- Yonghe Ding
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Alexey V Dvornikov
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiao Ma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN 55905, USA
- Mayo Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| | - Hong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Clinical Center for Gene Diagnosis and Therapy, the Second Xiangya Hospital of Central South University, Changsha, China 410011
| | - Yong Wang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Institute of Life Science, Beijing University of Chinese Medicine, Beijing, China 100029
| | | | - Rene R Packard
- School of Medicine, University of California Los Angeles, Los Angeles, CA 90073, USA
| | - Lei Wang
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jun Chen
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuji Zhang
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tzung Hsiai
- School of Medicine, University of California Los Angeles, Los Angeles, CA 90073, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN 55905, USA
- Mayo Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
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Azad A, Poloni G, Sontayananon N, Jiang H, Gehmlich K. The giant titin: how to evaluate its role in cardiomyopathies. J Muscle Res Cell Motil 2019; 40:159-167. [PMID: 31147888 PMCID: PMC6726704 DOI: 10.1007/s10974-019-09518-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/28/2019] [Indexed: 01/02/2023]
Abstract
Titin, the largest protein known, has attracted a lot of interest in the cardiovascular field in recent years, since the discovery that truncating variants in titin are commonly found in patients with dilated cardiomyopathy. This review will discuss the contribution of variants in titin to inherited cardiac conditions (cardiomyopathies) and how model systems, such as animals and cellular systems, can help to provide insights into underlying disease mechanisms. It will also give an outlook onto exciting technological developments, such as in the field of CRISPR, which may facilitate future research on titin variants and their contributions to cardiomyopathies.
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Affiliation(s)
- Amar Azad
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, OX3 9DU, UK
- Swansea University Medical School, Swansea, SA2 8PP, UK
| | - Giulia Poloni
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, OX3 9DU, UK
| | - Naeramit Sontayananon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, OX3 9DU, UK
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, OX3 9DU, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, OX3 9DU, UK.
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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