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Sun Y, Liu X, Huang W, Le S, Yan J. Structural domain in the Titin N2B-us region binds to FHL2 in a force-activation dependent manner. Nat Commun 2024; 15:4496. [PMID: 38802383 DOI: 10.1038/s41467-024-48828-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/15/2024] [Indexed: 05/29/2024] Open
Abstract
Titin N2B unique sequence (N2B-us) is a 572 amino acid sequence that acts as an elastic spring to regulate muscle passive elasticity. It is thought to lack stable tertiary structures and is a force-bearing region that is regulated by mechanical stretching. In this study, the conformation of N2B-us and its interaction with four-and-a-half LIM domain protein 2 (FHL2) are investigated using AlphaFold2 predictions and single-molecule experimental validation. Surprisingly, a stable alpha/beta structural domain is predicted and confirmed in N2B-us that can be mechanically unfolded at forces of a few piconewtons. Additionally, more than twenty FHL2 LIM domain binding sites are predicted to spread throughout N2B-us. Single-molecule manipulation experiments reveals the force-dependent binding of FHL2 to the N2B-us structural domain. These findings provide insights into the mechano-sensing functions of N2B-us and its interactions with FHL2.
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Affiliation(s)
- Yuze Sun
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Xuyao Liu
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Wenmao Huang
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Shimin Le
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore.
- Department of Physics, National University of Singapore, Singapore, Singapore.
- Centre for Biological Imaging Sciences, National University of Singapore, Singapore, Singapore.
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, China.
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2
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Stroik D, Gregorich ZR, Raza F, Ge Y, Guo W. Titin: roles in cardiac function and diseases. Front Physiol 2024; 15:1385821. [PMID: 38660537 PMCID: PMC11040099 DOI: 10.3389/fphys.2024.1385821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The giant protein titin is an essential component of muscle sarcomeres. A single titin molecule spans half a sarcomere and mediates diverse functions along its length by virtue of its unique domains. The A-band of titin functions as a molecular blueprint that defines the length of the thick filaments, the I-band constitutes a molecular spring that determines cell-based passive stiffness, and various domains, including the Z-disk, I-band, and M-line, serve as scaffolds for stretch-sensing signaling pathways that mediate mechanotransduction. This review aims to discuss recent insights into titin's functional roles and their relationship to cardiac function. The role of titin in heart diseases, such as dilated cardiomyopathy and heart failure with preserved ejection fraction, as well as its potential as a therapeutic target, is also discussed.
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Affiliation(s)
- Dawson Stroik
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Zachery R. Gregorich
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Farhan Raza
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Ying Ge
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Wei Guo
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
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3
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Weston TGR, Rees M, Gautel M, Fraternali F. Walking with giants: The challenges of variant impact assessment in the giant sarcomeric protein titin. WIREs Mech Dis 2024; 16:e1638. [PMID: 38155593 DOI: 10.1002/wsbm.1638] [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: 06/15/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/30/2023]
Abstract
Titin, the so-called "third filament" of the sarcomere, represents a difficult challenge for the determination of damaging genetic variants. A single titin molecule extends across half the length of a sarcomere in striated muscle, fulfilling a variety of vital structural and signaling roles, and has been linked to an equally varied range of myopathies, resulting in a significant burden on individuals and healthcare systems alike. While the consequences of truncating variants of titin are well-documented, the ramifications of the missense variants prevalent in the general population are less so. We here present a compendium of titin missense variants-those that result in a single amino-acid substitution in coding regions-reported to be pathogenic and discuss these in light of the nature of titin and the variant position within the sarcomere and their domain, the structural, pathological, and biophysical characteristics that define them, and the methods used for characterization. Finally, we discuss the current knowledge and integration of the multiple fields that have contributed to our understanding of titin-related pathology and offer suggestions as to how these concurrent methodologies may aid the further development in our understanding of titin and hopefully extend to other, less well-studied giant proteins. This article is categorized under: Cardiovascular Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Timir G R Weston
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK
| | - Martin Rees
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK
| | - Mathias Gautel
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK
| | - Franca Fraternali
- Institute of Structural and Molecular Biology, University College London, London, UK
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4
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Nakhaei-Rad S, Haghighi F, Bazgir F, Dahlmann J, Busley AV, Buchholzer M, Kleemann K, Schänzer A, Borchardt A, Hahn A, Kötter S, Schanze D, Anand R, Funk F, Kronenbitter AV, Scheller J, Piekorz RP, Reichert AS, Volleth M, Wolf MJ, Cirstea IC, Gelb BD, Tartaglia M, Schmitt JP, Krüger M, Kutschka I, Cyganek L, Zenker M, Kensah G, Ahmadian MR. Molecular and cellular evidence for the impact of a hypertrophic cardiomyopathy-associated RAF1 variant on the structure and function of contractile machinery in bioartificial cardiac tissues. Commun Biol 2023; 6:657. [PMID: 37344639 PMCID: PMC10284840 DOI: 10.1038/s42003-023-05013-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 06/02/2023] [Indexed: 06/23/2023] Open
Abstract
Noonan syndrome (NS), the most common among RASopathies, is caused by germline variants in genes encoding components of the RAS-MAPK pathway. Distinct variants, including the recurrent Ser257Leu substitution in RAF1, are associated with severe hypertrophic cardiomyopathy (HCM). Here, we investigated the elusive mechanistic link between NS-associated RAF1S257L and HCM using three-dimensional cardiac bodies and bioartificial cardiac tissues generated from patient-derived induced pluripotent stem cells (iPSCs) harboring the pathogenic RAF1 c.770 C > T missense change. We characterize the molecular, structural, and functional consequences of aberrant RAF1-associated signaling on the cardiac models. Ultrastructural assessment of the sarcomere revealed a shortening of the I-bands along the Z disc area in both iPSC-derived RAF1S257L cardiomyocytes and myocardial tissue biopsies. The aforementioned changes correlated with the isoform shift of titin from a longer (N2BA) to a shorter isoform (N2B) that also affected the active force generation and contractile tensions. The genotype-phenotype correlation was confirmed using cardiomyocyte progeny of an isogenic gene-corrected RAF1S257L-iPSC line and was mainly reversed by MEK inhibition. Collectively, our findings uncovered a direct link between a RASopathy gene variant and the abnormal sarcomere structure resulting in a cardiac dysfunction that remarkably recapitulates the human disease.
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Affiliation(s)
- Saeideh Nakhaei-Rad
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Stem Cell Biology and Regenerative Medicine Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Fereshteh Haghighi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Clinic for Cardiothoracic and Vascular Surgery, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Farhad Bazgir
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Julia Dahlmann
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Institute of Human Genetics, University Hospital, Otto von Guericke-University, Magdeburg, Germany
| | - Alexandra Viktoria Busley
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Stem Cell Unit, Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells", University of Göttingen, Göttingen, Germany
| | - Marcel Buchholzer
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Karolin Kleemann
- Clinic for Cardiothoracic and Vascular Surgery, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Anne Schänzer
- Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
| | - Andrea Borchardt
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas Hahn
- Department of Child Neurology, Justus Liebig University Giessen, 35392, Giessen, Germany
| | - Sebastian Kötter
- Institute of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Denny Schanze
- Institute of Human Genetics, University Hospital, Otto von Guericke-University, Magdeburg, Germany
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Florian Funk
- Institute of Pharmacology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Annette Vera Kronenbitter
- Institute of Pharmacology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jürgen Scheller
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Roland P Piekorz
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Marianne Volleth
- Institute of Human Genetics, University Hospital, Otto von Guericke-University, Magdeburg, Germany
| | - Matthew J Wolf
- Department of Medicine and Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ion Cristian Cirstea
- Institute of Comparative Molecular Endocrinology, University of Ulm, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Bruce D Gelb
- Mindich Child Health and Development Institute and Departments of Pediatrics and Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Marco Tartaglia
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Joachim P Schmitt
- Institute of Pharmacology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Martina Krüger
- Institute of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ingo Kutschka
- Clinic for Cardiothoracic and Vascular Surgery, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Lukas Cyganek
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Stem Cell Unit, Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells", University of Göttingen, Göttingen, Germany
| | - Martin Zenker
- Institute of Human Genetics, University Hospital, Otto von Guericke-University, Magdeburg, Germany.
| | - George Kensah
- Clinic for Cardiothoracic and Vascular Surgery, University Medical Center Göttingen, Göttingen, Germany.
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany.
| | - Mohammad R Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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5
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Funk F, Kronenbitter A, Isić M, Flocke V, Gorreßen S, Semmler D, Brinkmann M, Beck K, Steinhoff O, Srivastava T, Barbosa DM, Voigt K, Wang L, Bottermann K, Kötter S, Grandoch M, Flögel U, Krüger M, Schmitt JP. Diabetes disturbs functional adaptation of the remote myocardium after ischemia/reperfusion. J Mol Cell Cardiol 2022; 173:47-60. [PMID: 36150524 DOI: 10.1016/j.yjmcc.2022.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 07/01/2022] [Accepted: 09/16/2022] [Indexed: 01/06/2023]
Abstract
Diabetes mellitus type 2 is associated with adverse clinical outcome after myocardial infarction. To better understand the underlying causes we here investigated sarcomere protein function and its calcium-dependent regulation in the non-ischemic remote myocardium (RM) of diabetic mice (db/db) after transient occlusion of the left anterior descending coronary artery. Before and 24 h after surgery db/db and non-diabetic db/+ underwent magnetic resonance imaging followed by histological and biochemical analyses of heart tissue. Intracellular calcium transients and sarcomere function were measured in isolated cardiomyocytes. Active and passive force generation was assessed in skinned fibers and papillary muscle preparations. Before ischemia and reperfusion (I/R), beat-to-beat calcium cycling was depressed in diabetic cardiomyocytes. Nevertheless, contractile function was preserved owing to increased myofilament calcium sensitivity and higher responsiveness of myocardial force production to β-adrenergic stimulation in db/db compared to db/+. In addition, protein kinase C activity was elevated in db/db hearts leading to strong phosphorylation of the titin PEVK region and increased titin-based tension of myofilaments. I/R impaired the function of whole hearts and RM sarcomeres in db/db to a larger extent than in non-diabetic db/+, and we identified several reasons. First, the amplitude and the kinetics of cardiomyocyte calcium transients were further reduced in the RM of db/db. Underlying causes involved altered expression of calcium regulatory proteins. Diabetes and I/R additively reduced phospholamban S16-phosphorylation by 80% (P < 000.1) leading to strong inhibition of the calcium ATPase SERCA2a. Second, titin stiffening was only observed in the RM of db/+, but not in the RM of db/db. Finally, db/db myofilament calcium sensitivity and force generation upon β-adrenergic stimulation were no longer enhanced over db/+ in the RM. The findings demonstrate that impaired cardiomyocyte calcium cycling of db/db hearts is compensated by increased myofilament calcium sensitivity and increased titin-based stiffness prior to I/R. In contrast, sarcomere function of the RM 24 h after I/R is poor because both these compensatory mechanisms fail and myocyte calcium handling is further depressed.
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Affiliation(s)
- Florian Funk
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Annette Kronenbitter
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Malgorzata Isić
- Institute of Cardiovascular Physiology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Vera Flocke
- Institute of Molecular Cardiology, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Simone Gorreßen
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Dominik Semmler
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Maximilian Brinkmann
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Katharina Beck
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Oliver Steinhoff
- Institute of Translational Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Tanu Srivastava
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - David Monteiro Barbosa
- Institute of Cardiovascular Physiology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Katharina Voigt
- Institute of Cardiovascular Physiology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Luzhou Wang
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Katharina Bottermann
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Sebastian Kötter
- Institute of Cardiovascular Physiology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Maria Grandoch
- Institute of Translational Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Ulrich Flögel
- Institute of Molecular Cardiology, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Martina Krüger
- Institute of Cardiovascular Physiology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Joachim P Schmitt
- Institute of Pharmacology, University Hospital Düsseldorf, and Cardiovascular Research Institute Düsseldorf (CARID), Universitätsstraße 1, 40225 Düsseldorf, Germany.
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6
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Li N, Hang W, Shu H, Zhou N. RBM20, a Therapeutic Target to Alleviate Myocardial Stiffness via Titin Isoforms Switching in HFpEF. Front Cardiovasc Med 2022; 9:928244. [PMID: 35783855 PMCID: PMC9243441 DOI: 10.3389/fcvm.2022.928244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/30/2022] [Indexed: 12/05/2022] Open
Abstract
Increased myocardial stiffness is critically involved in heart diseases with impaired cardiac compliance, especially heart failure with preserved ejection fraction (HFpEF). Myocardial stiffness mainly derives from cardiomyocyte- and extracellular matrix (ECM)-derived passive stiffness. Titin, a major component of sarcomeres, participates in myocardial passive stiffness and stress-sensitive signaling. The ratio of two titin isoforms, N2BA to N2B, was validated to influence diastolic dysfunction via several pathways. RNA binding motif protein 20 (RBM20) is a well-studied splicing factor of titin, functional deficiency of RBM20 in mice profile improved cardiac compliance and function, which indicated that RBM20 functions as a potential therapeutic target for mitigating myocardial stiffness by modulating titin isoforms. This minor review summarized how RBM20 and other splicing factors modify the titin isoforms ratio, therefore providing a promising target for improving the myocardial compliance of HFpEF.
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7
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Lu Z, Wu Y, Chen Y, Chen X, Wu R, Lu Q, Chen D, Huang R. Role of spt23 in Saccharomyces cerevisiae thermal tolerance. Appl Microbiol Biotechnol 2022; 106:3691-3705. [PMID: 35476152 PMCID: PMC9151549 DOI: 10.1007/s00253-022-11920-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 11/02/2022]
Abstract
spt23 plays multiple roles in the thermal tolerance of budding yeast. spt23 regulates unsaturated lipid acid (ULA) content in the cell, which can then significantly affect cellular thermal tolerance. Being a Ty suppressor, spt23 can also interact with transposons (Tys) that are contributors to yeast's adaptive evolution. Nevertheless, few studies have investigated whether and how much spt23 can exert its regulatory functions through transposons. In this study, expression quantitative trait loci (eQTL) analysis was conducted with thermal-tolerant Saccharomyces cerevisiae strains, and spt23 was identified as one of the most important genes in mutants. spt23-overexpression (OE), deletion (Del), and integrative-expressed (IE) strains were constructed. Their heat tolerance, ethanol production, the expression level of key genes, and lipid acid contents in the cell membranes were measured. Furthermore, LTR (long terminal repeat)-amplicon sequencing was used to profile yeast transposon activities in the treatments. The results showed the Del type had a higher survival rate, biomass, and ethanol production, revealing negative correlations between spt23 expression levels and thermal tolerance. Total unsaturated lipid acid (TULA) contents in cell membranes were lower in the Del type, indicating its negative association with spt23 expression levels. The Del type resulted in the lower richness and higher evenness in LTR distributions, as well as higher transposon activities. The intersection of 3 gene sets and regression analysis revealed the relative weight of spt23's direct and TY-induced influence is about 4:3. These results suggested a heat tolerance model in which spt23 increases cell thermal tolerance through transcriptional regulation in addition to spt23-transposon triggered unknown responses. KEY POINTS: • spt23 is a key gene for heat tolerance, important for LA contents but not vital. • Deletion of spt23 decreases in yeast's LTR richness but not in evenness. • The relative weight of spt23's direct and TY-induced influence is about 4:3.
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Affiliation(s)
- Zhilong Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, 530004, People's Republic of China.,College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, People's Republic of China.,National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Yanling Wu
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Ying Chen
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Xiaoling Chen
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Renzhi Wu
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Qi Lu
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Dong Chen
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China
| | - Ribo Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, 530004, People's Republic of China. .,College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, People's Republic of China. .,National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, People's Republic of China.
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8
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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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9
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van der Pijl RJ, Domenighetti AA, Sheikh F, Ehler E, Ottenheijm CAC, Lange S. The titin N2B and N2A regions: biomechanical and metabolic signaling hubs in cross-striated muscles. Biophys Rev 2021; 13:653-677. [PMID: 34745373 PMCID: PMC8553726 DOI: 10.1007/s12551-021-00836-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023] Open
Abstract
Muscle specific signaling has been shown to originate from myofilaments and their associated cellular structures, including the sarcomeres, costameres or the cardiac intercalated disc. Two signaling hubs that play important biomechanical roles for cardiac and/or skeletal muscle physiology are the N2B and N2A regions in the giant protein titin. Prominent proteins associated with these regions in titin are chaperones Hsp90 and αB-crystallin, members of the four-and-a-half LIM (FHL) and muscle ankyrin repeat protein (Ankrd) families, as well as thin filament-associated proteins, such as myopalladin. This review highlights biological roles and properties of the titin N2B and N2A regions in health and disease. Special emphasis is placed on functions of Ankrd and FHL proteins as mechanosensors that modulate muscle-specific signaling and muscle growth. This region of the sarcomere also emerged as a hotspot for the modulation of passive muscle mechanics through altered titin phosphorylation and splicing, as well as tethering mechanisms that link titin to the thin filament system.
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Affiliation(s)
| | - Andrea A. Domenighetti
- Shirley Ryan AbilityLab, Chicago, IL USA
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL USA
| | - Farah Sheikh
- Division of Cardiology, School of Medicine, UC San Diego, La Jolla, CA USA
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King’s College London, London, UK
| | - Coen A. C. Ottenheijm
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ USA
- Department of Physiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Stephan Lange
- Division of Cardiology, School of Medicine, UC San Diego, La Jolla, CA USA
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
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10
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Adekunle AO, Adzika GK, Mprah R, Ndzie Noah ML, Adu-Amankwaah J, Rizvi R, Akhter N, Sun H. Predominance of Heart Failure With Preserved Ejection Fraction in Postmenopausal Women: Intra- and Extra-Cardiomyocyte Maladaptive Alterations Scaffolded by Estrogen Deficiency. Front Cell Dev Biol 2021; 9:685996. [PMID: 34660569 PMCID: PMC8511782 DOI: 10.3389/fcell.2021.685996] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 09/09/2021] [Indexed: 12/11/2022] Open
Abstract
Heart failure (HF) remains a public health concern as it is associated with high morbidity and death rates. In particular, heart failure with preserved ejection fraction (HFpEF) represents the dominant (>50%) form of HF and mostly occurring among postmenopausal women. Hence, the initiation and progression of the left ventricular diastolic dysfunctions (LVDD) (a typically clinical manifestation of HFpEF) in postmenopausal women have been attributed to estrogen deficiency and the loss of its residue cardioprotective effects. In this review, from a pathophysiological and immunological standpoint, we discuss the probable multiple pathomechanisms resulting in HFpEF, which are facilitated by estrogen deficiency. The initial discussions recap estrogen and estrogen receptors (ERs) and β-adrenergic receptors (βARs) signaling under physiological/pathological states to facilitate cardiac function/dysfunction, respectively. By reconciling these prior discussions, attempts were made to explain how the loss of estrogen facilitates the disruptions both ERs and βARs-mediated signaling responsible for; the modulation of intra-cardiomyocyte calcium homeostasis, maintenance of cardiomyocyte cytoskeletal and extracellular matrix, the adaptive regulation of coronary microvascular endothelial functions and myocardial inflammatory responses. By scaffolding the disruption of these crucial intra- and extra-cardiomyocyte physiological functions, estrogen deficiency has been demonstrated to cause LVDD and increase the incidence of HFpEF in postmenopausal women. Finally, updates on the advancements in treatment interventions for the prevention of HFpEF were highlighted.
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Affiliation(s)
| | | | - Richard Mprah
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
| | | | | | | | - Nazma Akhter
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical University, Xuzhou, China.,Xuzhou Medical University, Xuzhou, China
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11
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Loescher CM, Hobbach AJ, Linke WA. Titin (TTN): from molecule to modifications, mechanics and medical significance. Cardiovasc Res 2021; 118:2903-2918. [PMID: 34662387 PMCID: PMC9648829 DOI: 10.1093/cvr/cvab328] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/13/2021] [Indexed: 12/19/2022] Open
Abstract
The giant sarcomere protein titin is a major determinant of cardiomyocyte stiffness and contributor to cardiac strain sensing. Titin-based forces are highly regulated in health and disease, which aids in the regulation of myocardial function, including cardiac filling and output. Due to the enormous size, complexity, and malleability of the titin molecule, titin properties are also vulnerable to dysregulation, as observed in various cardiac disorders. This review provides an overview of how cardiac titin properties can be changed at a molecular level, including the role isoform diversity and post-translational modifications (acetylation, oxidation, and phosphorylation) play in regulating myocardial stiffness and contractility. We then consider how this regulation becomes unbalanced in heart disease, with an emphasis on changes in titin stiffness and protein quality control. In this context, new insights into the key pathomechanisms of human cardiomyopathy due to a truncation in the titin gene (TTN) are discussed. Along the way, we touch on the potential for titin to be therapeutically targeted to treat acquired or inherited cardiac conditions, such as HFpEF or TTN-truncation cardiomyopathy.
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Affiliation(s)
- Christine M Loescher
- Institute of Physiology II, University Hospital Münster, Robert-Koch-Str. 27B, Münster, 48149 Germany
| | - Anastasia J Hobbach
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, University Hospital Münster, Münster, Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, Robert-Koch-Str. 27B, Münster, 48149 Germany
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12
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Liu Y, Wang C, Cheng P, Zhang S, Zhou W, Xu Y, Xu H, Ji G. FHL1 Inhibits the Progression of Colorectal Cancer by Regulating the Wnt/β-Catenin Signaling Pathway. J Cancer 2021; 12:5345-5354. [PMID: 34335951 PMCID: PMC8317513 DOI: 10.7150/jca.60543] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/15/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose: This study aims to explore the FHL1 expression level in colorectal cancer (CRC) patients, analyze its association with patient survival and investigate the role of FHL1 in CRC. Methods: We used secondary sequencing to profile mRNA expression in CRC tissue and corresponding adjacent normal tissue from four CRC patients. We focus on FHL1 and analyzed the association between its expression level and clinical indicators. Furthermore, we explored the functional role of FHL1 in colorectal cancer tumorigenesis by transfecting cells with siRNA or overexpression plasmids. Results: Hierarchical clustering revealed significantly differentially expressed mRNAs. FHL1 expression was significantly lower in CRC tissue than in adjacent normal tissue as well as in CRC cell lines relative to NCM460. Low FHL1 expression in CRC tissue correlated with poor patient survival. Our data demonstrated that overexpression of FHL1 inhibited the proliferation, colony formation potential, and expression of CdK4 and Cyclin D1, whereas ablating FHL1 promoted their proliferation and colony formation potential, suggesting that FHL1 acts as a tumor suppressor in CRC. Moreover, we showed that FHL1 inhibited the proliferation of colorectal cancer cells by negatively regulating the Wnt/β-catenin signaling pathway. Conclusion: FHL1 is a potential tumor suppressor gene in colorectal cancer, and regulation of the FHL1-Wnt/β-catenin pathway may be part of its antitumor mechanism.
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Affiliation(s)
- Yujing Liu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Chunyan Wang
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Peiqiu Cheng
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Shengan Zhang
- Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Wenjun Zhou
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Yangxian Xu
- Department of General Surgery, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Hanchen Xu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Guang Ji
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
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13
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Complex functionality of protein phosphatase 1 isoforms in the heart. Cell Signal 2021; 85:110059. [PMID: 34062239 DOI: 10.1016/j.cellsig.2021.110059] [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: 01/04/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1(PP1) is a key regulator of cardiac function through dephosphorylating serine/threonine residues within target proteins to oppose the function of protein kinases. Studies from failing hearts of animal models and human patients have demonstrated significant increase of PP1 activity in myocardium, while elevated PP1 activity in transgenic mice leads to cardiac dysfunction, suggesting that PP1 might be a therapeutic target to ameliorate cardiac dysfunction in failing hearts. In fact, cardiac overexpression of inhibitor 1, the endogenous inhibitor of PP1, increases cardiac contractility and suppresses heart failure progression. However, this notion of PP1 inhibition for heart failure treatment has been challenged by recent studies on the isoform-specific roles of PP1 in the heart. PP1 is a holoenzyme composed of catalytic subunits (PP1α, PP1β, or PP1γ) and regulatory proteins that target them to distinct subcellular locations for functional specificity. This review will summarize how PP1 regulates phosphorylation of some of the key cardiac proteins involved in Ca2+ handling and cardiac contraction, and the potential role of PP1 isoforms in controlling cardiac physiology and pathophysiology.
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14
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Bonilla DA, Kreider RB, Stout JR, Forero DA, Kerksick CM, Roberts MD, Rawson ES. Metabolic Basis of Creatine in Health and Disease: A Bioinformatics-Assisted Review. Nutrients 2021; 13:nu13041238. [PMID: 33918657 PMCID: PMC8070484 DOI: 10.3390/nu13041238] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 02/06/2023] Open
Abstract
Creatine (Cr) is a ubiquitous molecule that is synthesized mainly in the liver, kidneys, and pancreas. Most of the Cr pool is found in tissues with high-energy demands. Cr enters target cells through a specific symporter called Na+/Cl−-dependent Cr transporter (CRT). Once within cells, creatine kinase (CK) catalyzes the reversible transphosphorylation reaction between [Mg2+:ATP4−]2− and Cr to produce phosphocreatine (PCr) and [Mg2+:ADP3−]−. We aimed to perform a comprehensive and bioinformatics-assisted review of the most recent research findings regarding Cr metabolism. Specifically, several public databases, repositories, and bioinformatics tools were utilized for this endeavor. Topics of biological complexity ranging from structural biology to cellular dynamics were addressed herein. In this sense, we sought to address certain pre-specified questions including: (i) What happens when creatine is transported into cells? (ii) How is the CK/PCr system involved in cellular bioenergetics? (iii) How is the CK/PCr system compartmentalized throughout the cell? (iv) What is the role of creatine amongst different tissues? and (v) What is the basis of creatine transport? Under the cellular allostasis paradigm, the CK/PCr system is physiologically essential for life (cell survival, growth, proliferation, differentiation, and migration/motility) by providing an evolutionary advantage for rapid, local, and temporal support of energy- and mechanical-dependent processes. Thus, we suggest the CK/PCr system acts as a dynamic biosensor based on chemo-mechanical energy transduction, which might explain why dysregulation in Cr metabolism contributes to a wide range of diseases besides the mitigating effect that Cr supplementation may have in some of these disease states.
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Affiliation(s)
- Diego A. Bonilla
- Research Division, Dynamical Business & Science Society–DBSS International SAS, Bogotá 110861, Colombia
- Research Group in Biochemistry and Molecular Biology, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
- Research Group in Physical Activity, Sports and Health Sciences (GICAFS), Universidad de Córdoba, Montería 230002, Colombia
- kDNA Genomics, Joxe Mari Korta Research Center, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
- Correspondence: ; Tel.: +57-320-335-2050
| | - Richard B. Kreider
- Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Texas A&M University, College Station, TX 77843, USA;
| | - Jeffrey R. Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL 32816, USA;
| | - Diego A. Forero
- Professional Program in Sport Training, School of Health and Sport Sciences, Fundación Universitaria del Área Andina, Bogotá 111221, Colombia;
| | - Chad M. Kerksick
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, Saint Charles, MO 63301, USA;
| | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA;
- Edward via College of Osteopathic Medicine, Auburn, AL 36849, USA
| | - Eric S. Rawson
- Department of Health, Nutrition and Exercise Science, Messiah University, Mechanicsburg, PA 17055, USA;
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15
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Fleming JR, Rani A, Kraft J, Zenker S, Börgeson E, Lange S. Exploring Obscurin and SPEG Kinase Biology. J Clin Med 2021; 10:jcm10050984. [PMID: 33801198 PMCID: PMC7957886 DOI: 10.3390/jcm10050984] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 12/15/2022] Open
Abstract
Three members of the obscurin protein family that contain tandem kinase domains with important signaling functions for cardiac and striated muscles are the giant protein obscurin, its obscurin-associated kinase splice isoform, and the striated muscle enriched protein kinase (SPEG). While there is increasing evidence for the specific roles that each individual kinase domain plays in cross-striated muscles, their biology and regulation remains enigmatic. Our present study focuses on kinase domain 1 and the adjacent low sequence complexity inter-kinase domain linker in obscurin and SPEG. Using Phos-tag gels, we show that the linker in obscurin contains several phosphorylation sites, while the same region in SPEG remained unphosphorylated. Our homology modeling, mutational analysis and molecular docking demonstrate that kinase 1 in obscurin harbors all key amino acids important for its catalytic function and that actions of this domain result in autophosphorylation of the protein. Our bioinformatics analyses also assign a list of putative substrates for kinase domain 1 in obscurin and SPEG, based on the known and our newly proposed phosphorylation sites in muscle proteins, including obscurin itself.
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Affiliation(s)
- Jennifer R. Fleming
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
- Correspondence: (J.R.F.); (E.B.); (S.L.)
| | - Alankrita Rani
- Centre for Molecular and Translational Medicine, The Wallenberg Laboratory and Wallenberg, Department of Molecular and Clinical Medicine, University of Gothenburg, 41345 Gothenburg, Sweden; (A.R.); (J.K.)
| | - Jamie Kraft
- Centre for Molecular and Translational Medicine, The Wallenberg Laboratory and Wallenberg, Department of Molecular and Clinical Medicine, University of Gothenburg, 41345 Gothenburg, Sweden; (A.R.); (J.K.)
| | - Sanja Zenker
- Department of Medicine, University of California, San Diego, CA 92093, USA;
| | - Emma Börgeson
- Centre for Molecular and Translational Medicine, The Wallenberg Laboratory and Wallenberg, Department of Molecular and Clinical Medicine, University of Gothenburg, 41345 Gothenburg, Sweden; (A.R.); (J.K.)
- Department of Clinical Physiology, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden
- Correspondence: (J.R.F.); (E.B.); (S.L.)
| | - Stephan Lange
- Centre for Molecular and Translational Medicine, The Wallenberg Laboratory and Wallenberg, Department of Molecular and Clinical Medicine, University of Gothenburg, 41345 Gothenburg, Sweden; (A.R.); (J.K.)
- Department of Medicine, University of California, San Diego, CA 92093, USA;
- Correspondence: (J.R.F.); (E.B.); (S.L.)
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16
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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: 10] [Impact Index Per Article: 3.3] [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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17
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Michel K, Herwig M, Werner F, Špiranec Spes K, Abeßer M, Schuh K, Dabral S, Mügge A, Baba HA, Skryabin BV, Hamdani N, Kuhn M. C-type natriuretic peptide moderates titin-based cardiomyocyte stiffness. JCI Insight 2020; 5:139910. [PMID: 33055420 PMCID: PMC7710274 DOI: 10.1172/jci.insight.139910] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/09/2020] [Indexed: 12/11/2022] Open
Abstract
Heart failure is often accompanied by titin-dependent myocardial stiffness. Phosphorylation of titin by cGMP-dependent protein kinase I (PKGI) increases cardiomyocyte distensibility. The upstream pathways stimulating PKGI-mediated titin phosphorylation are unclear. We studied whether C-type natriuretic peptide (CNP), via its guanylyl cyclase-B (GC-B) receptor and cGMP/PKGI signaling, modulates titin-based ventricular compliance. To dissect GC-B–mediated effects of endogenous CNP in cardiomyocytes, we generated mice with cardiomyocyte-restricted GC-B deletion (CM GC-B–KO mice). The impact on heart morphology and function, myocyte passive tension, and titin isoform expression and phosphorylation was studied at baseline and after increased afterload induced by transverse aortic constriction (TAC). Pressure overload increased left ventricular endothelial CNP expression, with an early peak after 3 days. Concomitantly, titin phosphorylation at Ser4080, the site phosphorylated by PKGI, was augmented. Notably, in CM GC-B–KO mice this titin response was abolished. TAC-induced hypertrophy and fibrosis were not different between genotypes. However, the KO mice presented mild systolic and diastolic dysfunction together with myocyte stiffness, which were not observed in control littermates. In vitro, recombinant PKGI rescued reduced titin-Ser4080 phosphorylation and reverted passive stiffness of GC-B–deficient cardiomyocytes. CNP-induced activation of GC-B/cGMP/PKGI signaling in cardiomyocytes provides a protecting regulatory circuit preventing titin-based myocyte stiffening during early phases of pressure overload. C-type natriuretic peptide via GC-B/cGMP/PKGI signalling in cardiomyocytes attenuates titin-based cardiomyocyte stiffening during early phases of pressure-overload.
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Affiliation(s)
- Konstanze Michel
- Institute of Physiology, University of Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Melissa Herwig
- Institute of Physiology and.,Department of Cardiology, St-Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Franziska Werner
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | | | - Marco Abeßer
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Kai Schuh
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Swati Dabral
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Andreas Mügge
- Department of Cardiology, St-Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Hideo A Baba
- Institute of Pathology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Boris V Skryabin
- Medical Faculty, Core Facility TRAnsgenic animal and genetic engineering Models (TRAM), University of Münster, Münster, Germany
| | - Nazha Hamdani
- Institute of Physiology and.,Department of Cardiology, St-Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
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18
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Kolijn D, Kovács Á, Herwig M, Lódi M, Sieme M, Alhaj A, Sandner P, Papp Z, Reusch PH, Haldenwang P, Falcão-Pires I, Linke WA, Jaquet K, Van Linthout S, Mügge A, Tschöpe C, Hamdani N. Enhanced Cardiomyocyte Function in Hypertensive Rats With Diastolic Dysfunction and Human Heart Failure Patients After Acute Treatment With Soluble Guanylyl Cyclase (sGC) Activator. Front Physiol 2020; 11:345. [PMID: 32523538 PMCID: PMC7261855 DOI: 10.3389/fphys.2020.00345] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/26/2020] [Indexed: 01/09/2023] Open
Abstract
Aims Our aim was to investigate the effect of nitric oxide (NO)-independent activation of soluble guanylyl cyclase (sGC) on cardiomyocyte function in a hypertensive animal model with diastolic dysfunction and in biopsies from human heart failure with preserved ejection fraction (HFpEF). Methods Dahl salt-sensitive (DSS) rats and control rats were fed a high-salt diet for 10 weeks and then acutely treated in vivo with the sGC activator BAY 58-2667 (cinaciguat) for 30 min. Single skinned cardiomyocyte passive stiffness (Fpassive) was determined in rats and human myocardium biopsies before and after acute treatment. Titin phosphorylation, activation of the NO/sGC/cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) cascade, as well as hypertrophic pathways including NO/sGC/cGMP/PKG, PKA, calcium–calmodulin kinase II (CaMKII), extracellular signal-regulated kinase 2 (ERK2), and PKC were assessed. In addition, we explored the contribution of pro-inflammatory cytokines and oxidative stress levels to the modulation of cardiomyocyte function. Immunohistochemistry and electron microscopy were used to assess the translocation of sGC and connexin 43 proteins in the rat model before and after treatment. Results High cardiomyocyte Fpassive was found in rats and human myocardial biopsies compared to control groups, which was attributed to hypophosphorylation of total titin and to deranged site-specific phosphorylation of elastic titin regions. This was accompanied by lower levels of PKG and PKA activity, along with dysregulation of hypertrophic pathway markers such as CaMKII, PKC, and ERK2. Furthermore, DSS rats and human myocardium biopsies showed higher pro-inflammatory cytokines and oxidative stress compared to controls. DSS animals benefited from treatment with the sGC activator, as Fpassive, titin phosphorylation, PKG and the hypertrophic pathway kinases, pro-inflammatory cytokines, and oxidative stress markers all significantly improved to the level observed in controls. Immunohistochemistry and electron microscopy revealed a translocation of sGC protein toward the intercalated disc and t-tubuli following treatment in both control and DSS samples. This translocation was confirmed by staining for the gap junction protein connexin 43 at the intercalated disk. DSS rats showed a disrupted connexin 43 pattern, and sGC activator was able to partially reduce disruption and increase expression of connexin 43. In human HFpEF biopsies, the high Fpassive, reduced titin phosphorylation, dysregulation of the NO–sGC–cGMP–PKG pathway and PKA activity level, and activity of kinases involved in hypertrophic pathways CaMKII, PKC, and ERK2 were all significantly improved by sGC treatment and accompanied by a reduction in pro-inflammatory cytokines and oxidative stress markers. Conclusion Our data show that sGC activator improves cardiomyocyte function, reduces inflammation and oxidative stress, improves sGC–PKG signaling, and normalizes hypertrophic kinases, indicating that it is a potential treatment option for HFpEF patients and perhaps also for cases with increased hypertrophic signaling.
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Affiliation(s)
- Detmar Kolijn
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Árpád Kovács
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Melissa Herwig
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Mária Lódi
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany.,Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,University of Debrecen, Kálmán Laki Doctoral School, Debrecen, Hungary
| | - Marcel Sieme
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany
| | - Abdulatif Alhaj
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany
| | - Peter Sandner
- Bayer AG, Drug Discovery Cardiology, Wuppertal, Germany
| | - Zoltán Papp
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Peter H Reusch
- Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany
| | - Peter Haldenwang
- Department of Cardiothoracic Surgery, University Hospital Bergmannsheil Bochum, Bochum, Germany
| | - Ines Falcão-Pires
- Department of Surgery and Physiology and Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, University of Münster, Münster, Germany
| | - Kornelia Jaquet
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany
| | - Sophie Van Linthout
- Department of Medicine and Cardiology (CVK), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Andreas Mügge
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany
| | - Carsten Tschöpe
- Department of Medicine and Cardiology (CVK), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Nazha Hamdani
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Joseph Hospital, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
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19
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Herwig M, Kolijn D, Lódi M, Hölper S, Kovács Á, Papp Z, Jaquet K, Haldenwang P, Dos Remedios C, Reusch PH, Mügge A, Krüger M, Fielitz J, Linke WA, Hamdani N. Modulation of Titin-Based Stiffness in Hypertrophic Cardiomyopathy via Protein Kinase D. Front Physiol 2020; 11:240. [PMID: 32351396 PMCID: PMC7174613 DOI: 10.3389/fphys.2020.00240] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/02/2020] [Indexed: 12/21/2022] Open
Abstract
The giant protein titin performs structure-preserving functions in the sarcomere and is important for the passive stiffness (Fpassive) of cardiomyocytes. Protein kinase D (PKD) enzymes play crucial roles in regulating myocardial contraction, hypertrophy, and remodeling. PKD phosphorylates myofilament proteins, but it is not known whether the giant protein titin is also a PKD substrate. Here, we aimed to determine whether PKD phosphorylates titin and thereby modulates cardiomyocyte Fpassive in normal and failing myocardium. The phosphorylation of titin was assessed in cardiomyocyte-specific PKD knock-out mice (cKO) and human hearts using immunoblotting with a phosphoserine/threonine and a phosphosite-specific titin antibody. PKD-dependent site-specific titin phosphorylation in vivo was quantified by mass spectrometry using stable isotope labeling by amino acids in cell culture (SILAC) of SILAC-labeled mouse heart protein lysates that were mixed with lysates isolated from hearts of either wild-type control (WT) or cKO mice. Fpassive of single permeabilized cardiomyocytes was recorded before and after PKD and HSP27 administration. All-titin phosphorylation was reduced in cKO compared to WT hearts. Multiple conserved PKD-dependent phosphosites were identified within the Z-disk, A-band and M-band regions of titin by quantitative mass spectrometry, and many PKD-dependent phosphosites detected in the elastic titin I-band region were significantly decreased in cKO. Analysis of titin site-specific phosphorylation showed unaltered or upregulated phosphorylation in cKO compared to matched WT hearts. Fpassive was elevated in cKO compared to WT cardiomyocytes and PKD administration lowered Fpassive of WT and cKO cardiomyocytes. Cardiomyocytes from hypertrophic cardiomyopathy (HCM) patients showed higher Fpassive compared to control hearts and significantly lower Fpassive after PKD treatment. In addition, we found higher phosphorylation at CaMKII-dependent titin sites in HCM compared to control hearts. Expression and phosphorylation of HSP27, a substrate of PKD, were elevated in HCM hearts, which was associated with increased PKD expression and phosphorylation. The relocalization of HSP27 in HCM away from the sarcomeric Z-disk and I-band suggested that HSP27 failed to exert its protective action on titin extensibility. This protection could, however, be restored by administration of HSP27, which significantly reduced Fpassive in HCM cardiomyocytes. These findings establish a previously unknown role for PKDin regulating diastolic passive properties of healthy and diseased hearts.
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Affiliation(s)
- Melissa Herwig
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Detmar Kolijn
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Mária Lódi
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - Soraya Hölper
- Sanofi-Aventis Deutschland GmbH Industriepark Höchst, Frankfurt, Germany
| | - Árpád Kovács
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany
| | - Zoltán Papp
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Kornelia Jaquet
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany
| | - Peter Haldenwang
- Department of Cardiothoracic Surgery, University Hospital Bergmannsheil Bochum, Bochum, Germany
| | - Cris Dos Remedios
- School of Medical Sciences, Bosch Institute, University of Sydney, Camperdown, NSW, Australia
| | - Peter H Reusch
- Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany
| | - Andreas Mügge
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany
| | - Marcus Krüger
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Jens Fielitz
- Department of Internal Medicine B, Cardiology, University Medicine Greifswald, Greifswald, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, University of Münster, Münster, Germany
| | - Nazha Hamdani
- Department of Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Bochums, Germany.,Department of Clinical Pharmacology, Ruhr University Bochum, Bochum, Germany.,Institute of Physiology, Ruhr University Bochum, Bochum, Germany
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20
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Ward M, Iskratsch T. Mix and (mis-)match - The mechanosensing machinery in the changing environment of the developing, healthy adult and diseased heart. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118436. [PMID: 30742931 PMCID: PMC7042712 DOI: 10.1016/j.bbamcr.2019.01.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/07/2019] [Accepted: 01/29/2019] [Indexed: 01/01/2023]
Abstract
The composition and the stiffness of cardiac microenvironment change during development and/or in heart disease. Cardiomyocytes (CMs) and their progenitors sense these changes, which decides over the cell fate and can trigger CM (progenitor) proliferation, differentiation, de-differentiation or death. The field of mechanobiology has seen a constant increase in output that also includes a wealth of new studies specific to cardiac or cardiomyocyte mechanosensing. As a result, mechanosensing and transduction in the heart is increasingly being recognised as a main driver of regulating the heart formation and function. Recent work has for instance focused on measuring the molecular, physical and mechanical changes of the cellular environment - as well as intracellular contributors to the passive stiffness of the heart. On the other hand, a variety of new studies shed light into the molecular machinery that allow the cardiomyocytes to sense these properties. Here we want to discuss the recent work on this topic, but also specifically focus on how the different components are regulated at various stages during development, in health or disease in order to highlight changes that might contribute to disease progression and heart failure.
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Key Words
- cm, cardiomyocytes
- hcm, hypertrophic cardiomyopathy
- dcm, dilated cardiomyopathy
- icm, idiopathic cardiomyopathy
- myh, myosin heavy chain
- tnnt, troponin t
- tnni, troponin i
- afm, atomic force microscope
- mre, magnetic resonance elastography
- swe, ultrasound cardiac shear-wave elastography
- lv, left ventricle
- lox, lysyl oxidase
- loxl, lysyl oxidase like protein
- lh, lysyl hydroxylase
- lys, lysin
- lccs, lysald-derived collagen crosslinks
- hlccs, hylald-derived collagen crosslinks
- pka, protein kinase a
- pkc, protein kinase c
- vash1, vasohibin-1
- svbp, small vasohibin binding protein
- tcp, tubulin carboxypeptidase
- ttl, tubulin tyrosine ligase
- mrtf, myocardin-related transcription factor
- gap, gtpase activating protein
- gef, guanine nucleotide exchange factor
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Affiliation(s)
- Matthew Ward
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, United Kingdom
| | - Thomas Iskratsch
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, United Kingdom.
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21
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Trum M, Wagner S, Maier LS, Mustroph J. CaMKII and GLUT1 in heart failure and the role of gliflozins. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165729. [PMID: 32068116 DOI: 10.1016/j.bbadis.2020.165729] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Abstract
Empagliflozin, a selective sodium-glucose co-transporter 2 (SGLT2) inhibitor, has been shown to reduce mortality and hospitalization for heart failure in diabetic patients in the EMPA-REG-OUTCOME trial (Zinman et al., 2015). Surprisingly, dapagliflozin, another SGLT2 inhibitor, exerted comparable effects on clinical endpoints even in the absence of diabetes mellitus (DAPA-HF trial) (McMurray et al., 2019). There is a myriad of suggested underlying mechanisms ranging from improved glycemic control and hemodynamic effects to altered myocardial metabolism, inflammation, neurohumoral activation and intracellular ion homeostasis. Here, we review the effects of gliflozins on cardiac electro-mechanical coupling with an emphasis on novel CaMKII-mediated pathways and on cardiac glucose and ketone metabolism in the failing heart. We focus on empagliflozin as it is the gliflozin with the most abundant experimental evidence for direct effects on the heart. Where useful, we aim to compare empagliflozin to other gliflozins. To facilitate understanding of empagliflozin-induced alterations, we first give a short summary of the pathophysiological role of CaMKII in heart failure, as well as cardiac changes of glucose and ketone body metabolism in the failing heart.
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Affiliation(s)
- M Trum
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - S Wagner
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - L S Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - J Mustroph
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany.
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22
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Radke MH, Polack C, Methawasin M, Fink C, Granzier HL, Gotthardt M. Deleting Full Length Titin Versus the Titin M-Band Region Leads to Differential Mechanosignaling and Cardiac Phenotypes. Circulation 2020; 139:1813-1827. [PMID: 30700140 DOI: 10.1161/circulationaha.118.037588] [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] [Indexed: 12/31/2022]
Abstract
BACKGROUND Titin is a giant elastic protein that spans the half-sarcomere from Z-disk to M-band. It acts as a molecular spring and mechanosensor and has been linked to striated muscle disease. The pathways that govern titin-dependent cardiac growth and contribute to disease are diverse and difficult to dissect. METHODS To study titin deficiency versus dysfunction, the authors generated and compared striated muscle specific knockouts (KOs) with progressive postnatal loss of the complete titin protein by removing exon 2 (E2-KO) or an M-band truncation that eliminates proper sarcomeric integration, but retains all other functional domains (M-band exon 1/2 [M1/2]-KO). The authors evaluated cardiac function, cardiomyocyte mechanics, and the molecular basis of the phenotype. RESULTS Skeletal muscle atrophy with reduced strength, severe sarcomere disassembly, and lethality from 2 weeks of age were shared between the models. Cardiac phenotypes differed considerably: loss of titin leads to dilated cardiomyopathy with combined systolic and diastolic dysfunction-the absence of M-band titin to cardiac atrophy and preserved function. The elastic properties of M1/2-KO cardiomyocytes are maintained, while passive stiffness is reduced in the E2-KO. In both KOs, we find an increased stress response and increased expression of proteins linked to titin-based mechanotransduction (CryAB, ANKRD1, muscle LIM protein, FHLs, p42, Camk2d, p62, and Nbr1). Among them, FHL2 and the M-band signaling proteins p62 and Nbr1 are exclusively upregulated in the E2-KO, suggesting a role in the differential pathology of titin truncation versus deficiency of the full-length protein. The differential stress response is consistent with truncated titin contributing to the mechanical properties in M1/2-KOs, while low titin levels in E2-KOs lead to reduced titin-based stiffness and increased strain on the remaining titin molecules. CONCLUSIONS Progressive depletion of titin leads to sarcomere disassembly and atrophy in striated muscle. In the complete knockout, remaining titin molecules experience increased strain, resulting in mechanically induced trophic signaling and eventually dilated cardiomyopathy. The truncated titin in M1/2-KO helps maintain the passive properties and thus reduces mechanically induced signaling. Together, these findings contribute to the molecular understanding of why titin mutations differentially affect cardiac growth and have implications for genotype-phenotype relations that support a personalized medicine approach to the diverse titinopathies.
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Affiliation(s)
- Michael H Radke
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany (M.H.R., C.P., C.F., M.G.).,DZHK: German Centre for Cardiovascular Research, Partner Site, Berlin, Germany (M.H.R., M.G.)
| | - Christopher Polack
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany (M.H.R., C.P., C.F., M.G.)
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson (M.M., H.G.). The current affiliation for P.S. and T.S. is Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Germany
| | - Claudia Fink
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany (M.H.R., C.P., C.F., M.G.)
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson (M.M., H.G.). The current affiliation for P.S. and T.S. is Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University Mainz, Germany
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany (M.H.R., C.P., C.F., M.G.).,DZHK: German Centre for Cardiovascular Research, Partner Site, Berlin, Germany (M.H.R., M.G.)
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23
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Tharp CA, Haywood ME, Sbaizero O, Taylor MRG, Mestroni L. The Giant Protein Titin's Role in Cardiomyopathy: Genetic, Transcriptional, and Post-translational Modifications of TTN and Their Contribution to Cardiac Disease. Front Physiol 2019; 10:1436. [PMID: 31849696 PMCID: PMC6892752 DOI: 10.3389/fphys.2019.01436] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/07/2019] [Indexed: 02/06/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is a leading cause of heart failure, sudden cardiac death and heart transplant. DCM is inherited in approximately 50% of cases, in which the most frequent genetic defects are truncation variants of the titin gene (TTNtv). TTN encodes titin, which is the largest protein in the body and is an essential component of the sarcomere. Titin serves as a biological spring, spanning half of the sarcomere and connecting the Z-disk to the M-line, with scaffold and signaling functions. Truncations of titin are believed to lead to either haploinsufficiency and loss-of-function, or to a “poison peptide” effect. However, other titin mechanisms are postulated to influence cardiac function including post-translational modifications, in particular changes in titin phosphorylation that alters the stiffness of the protein, and diversity of alternative splicing that generates different titin isoforms. In this article, we review the role of TTN mutations in development of DCM, how differential expression of titin isoforms relate to DCM pathophysiology, and discuss how post-translational modifications of titin can affect cardiomyocyte function. Current research efforts aim to elucidate the contribution of titin to myofibril assembly, stability, and signal transduction, and how mutant titin leads to cardiac dysfunction and human disease. Future research will need to translate this knowledge toward novel therapeutic approaches that can modulate titin transcriptional and post-translational defects to treat DCM and heart failure.
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Affiliation(s)
- Charles A Tharp
- Adult Medical Genetics Program and Cardiovascular Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Mary E Haywood
- Adult Medical Genetics Program and Cardiovascular Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Matthew R G Taylor
- Adult Medical Genetics Program and Cardiovascular Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Luisa Mestroni
- Adult Medical Genetics Program and Cardiovascular Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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24
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Liao D, Chen W, Tan CY, Wong JX, Chan PS, Tan LW, Foo R, Jiang J. Upregulation of Yy1 Suppresses Dilated Cardiomyopathy caused by Ttn insufficiency. Sci Rep 2019; 9:16330. [PMID: 31705051 PMCID: PMC6841687 DOI: 10.1038/s41598-019-52796-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 10/21/2019] [Indexed: 12/31/2022] Open
Abstract
Truncating variants in TTN (TTNtv), coding for the largest structural protein in the sarcomere, contribute to the largest portion of familial and ambulatory dilated cardiomyopathy (DCM). TTN haploinsufficiency caused by TTNtv is suggested as the disease mechanism. However, it is unclear whether TTN insufficiency causes DCM. Moreover, it is unknown whether modulation of downstream pathways serves as a therapeutic strategy for DCM caused by TTN insufficiency. Here, we show that reduction of cardiac Ttn expression by adeno-associated virus mediated shRNA (Ttn shRNA) generated DCM in mouse, demonstrating impaired cardiac performance, enlarged left ventricle (LV) and reduced LV wall thickness. A screen of 10 dysregulated and selected genes identified that Yin Yang 1 (Yy1) significantly suppressed DCM caused by Ttn shRNA. Gene profiling by RNAseq showed Yy1 modulated cell growth related genes. Ttn insufficiency activated cardiomyocyte cell cycle reentry by upregulating of Ccnd1 and Ccnd2. Cardiomyocytes activated by Ttn insufficiency did not advance to S phase by EdU incorporation assay. Yy1 promoted cardiomyocyte cell cycle by further enhancing Ccnd1 and Ccnd2 and increasing DNA replication without undergoing cell division. Importantly, upregulation of Ccnd1 and Ccnd2 suppressed DCM caused by Ttn insufficiency. Our findings demonstrate that DCM caused by Ttn insufficiency can be treated by therapeutically promoting cardiac cell cycle.
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Affiliation(s)
- Dan Liao
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore
| | - Weiming Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore
| | - Chia Yee Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore
| | - Jing Xuan Wong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore
| | - Pui Shi Chan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore
| | - Lek Wen Tan
- Genome Institute of Singapore, A*STAR, Singapore, 138672, Singapore
| | - Roger Foo
- Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore.,Genome Institute of Singapore, A*STAR, Singapore, 138672, Singapore
| | - Jianming Jiang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore. .,Cardiovascular Research Institute, National University Health System, Centre for Translational Medicine, Singapore, 117599, Singapore.
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25
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Salcan S, Bongardt S, Monteiro Barbosa D, Efimov IR, Rassaf T, Krüger M, Kötter S. Elastic titin properties and protein quality control in the aging heart. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118532. [PMID: 31421188 DOI: 10.1016/j.bbamcr.2019.118532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 07/12/2019] [Accepted: 08/12/2019] [Indexed: 01/09/2023]
Abstract
Cardiac aging affects the heart on the functional, structural, and molecular level and shares characteristic hallmarks with the development of chronic heart failure. Apart from age-dependent left ventricular hypertrophy and fibrosis that impairs diastolic function, diminished activity of cardiac protein-quality-control systems increases the risk of cytotoxic accumulation of defective proteins. Here, we studied the impact of cardiac aging on the sarcomeric protein titin by analyzing titin-based cardiomyocyte passive tension, titin modification and proteasomal titin turnover. We analyzed left ventricular samples from young (6 months) and old (20 months) wild-type mice and healthy human donor patients grouped according to age in young (17-50 years) and aged hearts (51-73 years). We found no age-dependent differences in titin isoform composition of mouse or human hearts. In aged hearts from mice and human we determined altered titin phosphorylation at serine residues S4010 and S4099 in the elastic N2B domain, but no significant changes in phosphorylation of S11878 and S12022 in the elastic PEVK region. Importantly, overall titin-based cardiomyocyte passive tension remained unchanged. In aged hearts, the calcium-activated protease calpain-1, which provides accessibility to ubiquitination by releasing titin from the sarcomere, showed decreased proteolytic activity. In addition, we observed a reduction in the proteasomal activities. Taken together, our data indicate that cardiac aging does not affect titin-based passive properties of the cardiomyocytes, but impairs protein-quality control, including titin, which may result in a diminished adaptive capacity of the aged myocardium.
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Affiliation(s)
- Senem Salcan
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Sabine Bongardt
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany
| | - David Monteiro Barbosa
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Igor R Efimov
- George Washington University, Department of Biomedical Engineering, Science and Engineering Hall, Washington DC-20052, USA
| | - Tienush Rassaf
- University Hospital Essen, Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, 45147 Essen, Germany
| | - Martina Krüger
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany.
| | - Sebastian Kötter
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany.
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26
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Jaffré F, Miller CL, Schänzer A, Evans T, Roberts AE, Hahn A, Kontaridis MI. Inducible Pluripotent Stem Cell-Derived Cardiomyocytes Reveal Aberrant Extracellular Regulated Kinase 5 and Mitogen-Activated Protein Kinase Kinase 1/2 Signaling Concomitantly Promote Hypertrophic Cardiomyopathy in RAF1-Associated Noonan Syndrome. Circulation 2019; 140:207-224. [PMID: 31163979 DOI: 10.1161/circulationaha.118.037227] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND More than 90% of individuals with Noonan syndrome (NS) with mutations clustered in the CR2 domain of RAF1 present with severe and often lethal hypertrophic cardiomyopathy (HCM). The signaling pathways by which NS RAF1 mutations promote HCM remain elusive, and so far, there is no known treatment for NS-associated HCM. METHODS We used patient-derived RAF1S257L/+ and CRISPR-Cas9-generated isogenic control inducible pluripotent stem cell (iPSC)-derived cardiomyocytes to model NS RAF1-associated HCM and to further delineate the molecular mechanisms underlying the disease. RESULTS We show that mutant iPSC-derived cardiomyocytes phenocopy the pathology seen in hearts of patients with NS by exhibiting hypertrophy and structural defects. Through pharmacological and genetic targeting, we identify 2 perturbed concomitant pathways that, together, mediate HCM in RAF1 mutant iPSC-derived cardiomyocytes. Hyperactivation of mitogen-activated protein kinase kinase 1/2 (MEK1/2), but not extracellular regulated kinase 1/2, causes myofibrillar disarray, whereas the enlarged cardiomyocyte phenotype is a direct consequence of increased extracellular regulated kinase 5 (ERK5) signaling, a pathway not previously known to be involved in NS. RNA-sequencing reveals genes with abnormal expression in RAF1 mutant iPSC-derived cardiomyocytes and identifies subsets of genes dysregulated by aberrant MEK1/2 or ERK5 pathways that could contribute to the NS-associated HCM. CONCLUSIONS Taken together, the results of our study identify the molecular mechanisms by which NS RAF1 mutations cause HCM and reveal downstream effectors that could serve as therapeutic targets for treatment of NS and perhaps other, more common, congenital HCM disorders.
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Affiliation(s)
- Fabrice Jaffré
- Department of Medicine, Division of Cardiology, Beth Israel Deaconess Medical Center (F.J., M.I.K.).,Harvard Medical School, Boston, MA (F.J., M.I.K.).,Department of Surgery, Weill Cornell Medical College, New York, NY (F.J., T.E.)
| | - Clint L Miller
- Center for Public Health Genomics, Department of Public Health Sciences, Biochemistry and Molecular Genetics, and Biomedical Engineering, University of Virginia, Charlottesville (C.L.M.)
| | - Anne Schänzer
- Institute of Neuropathology (A.S.), University Hospital Giessen, Justus Liebig University Giessen, Germany
| | - Todd Evans
- Department of Surgery, Weill Cornell Medical College, New York, NY (F.J., T.E.)
| | - Amy E Roberts
- Department of Cardiology, Division of Genetics, Boston Children's Hospital, MA (A.E.R.)
| | - Andreas Hahn
- Department of Child Neurology (A.H.), University Hospital Giessen, Justus Liebig University Giessen, Germany
| | - Maria I Kontaridis
- Department of Medicine, Division of Cardiology, Beth Israel Deaconess Medical Center (F.J., M.I.K.).,Department of Biological Chemistry and Molecular Pharmacology (M.I.K.).,Harvard Medical School, Boston, MA (F.J., M.I.K.).,Harvard Stem Cell Institute, Harvard University, Cambridge, MA (M.I.K.).,Masonic Medical Research Institute, Utica, NY (M.I.K.)
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27
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Saucerman JJ, Tan PM, Buchholz KS, McCulloch AD, Omens JH. Mechanical regulation of gene expression in cardiac myocytes and fibroblasts. Nat Rev Cardiol 2019; 16:361-378. [PMID: 30683889 PMCID: PMC6525041 DOI: 10.1038/s41569-019-0155-8] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The intact heart undergoes complex and multiscale remodelling processes in response to altered mechanical cues. Remodelling of the myocardium is regulated by a combination of myocyte and non-myocyte responses to mechanosensitive pathways, which can alter gene expression and therefore function in these cells. Cellular mechanotransduction and its downstream effects on gene expression are initially compensatory mechanisms during adaptations to the altered mechanical environment, but under prolonged and abnormal loading conditions, they can become maladaptive, leading to impaired function and cardiac pathologies. In this Review, we summarize mechanoregulated pathways in cardiac myocytes and fibroblasts that lead to altered gene expression and cell remodelling under physiological and pathophysiological conditions. Developments in systems modelling of the networks that regulate gene expression in response to mechanical stimuli should improve integrative understanding of their roles in vivo and help to discover new combinations of drugs and device therapies targeting mechanosignalling in heart disease.
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Affiliation(s)
- Jeffrey J Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Philip M Tan
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Kyle S Buchholz
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Andrew D McCulloch
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA.
| | - Jeffrey H Omens
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
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Koser F, Loescher C, Linke WA. Posttranslational modifications of titin from cardiac muscle: how, where, and what for? FEBS J 2019; 286:2240-2260. [PMID: 30989819 PMCID: PMC6850032 DOI: 10.1111/febs.14854] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/27/2019] [Accepted: 04/13/2019] [Indexed: 12/11/2022]
Abstract
Titin is a giant elastic protein expressed in the contractile units of striated muscle cells, including the sarcomeres of cardiomyocytes. The last decade has seen enormous progress in our understanding of how titin molecular elasticity is modulated in a dynamic manner to help cardiac sarcomeres adjust to the varying hemodynamic demands on the heart. Crucial events mediating the rapid modulation of cardiac titin stiffness are post‐translational modifications (PTMs) of titin. In this review, we first recollect what is known from earlier and recent work on the molecular mechanisms of titin extensibility and force generation. The main goal then is to provide a comprehensive overview of current insight into the relationship between titin PTMs and cardiomyocyte stiffness, notably the effect of oxidation and phosphorylation of titin spring segments on titin stiffness. A synopsis is given of which type of oxidative titin modification can cause which effect on titin stiffness. A large part of the review then covers the mechanically relevant phosphorylation sites in titin, their location along the elastic segment, and the protein kinases and phosphatases known to target these sites. We also include a detailed coverage of the complex changes in phosphorylation at specific titin residues, which have been reported in both animal models of heart disease and in human heart failure, and their correlation with titin‐based stiffness alterations. Knowledge of the relationship between titin PTMs and titin elasticity can be exploited in the search for therapeutic approaches aimed at softening the pathologically stiffened myocardium in heart failure patients.
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Schaefer A, Schneeberger Y, Schulz S, Krasemann S, Werner T, Piasecki A, Höppner G, Müller C, Morhenn K, Lorenz K, Wieczorek D, Schwoerer AP, Eschenhagen T, Ehmke H, Reichenspurner H, Stenzig J, Cuello F. Analysis of fibrosis in control or pressure overloaded rat hearts after mechanical unloading by heterotopic heart transplantation. Sci Rep 2019; 9:5710. [PMID: 30952943 PMCID: PMC6451012 DOI: 10.1038/s41598-019-42263-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 01/22/2019] [Indexed: 02/03/2023] Open
Abstract
Mechanical unloading (MU) by implantation of left ventricular assist devices (LVAD) has become clinical routine. This procedure has been shown to reverse cardiac pathological remodeling, with the underlying molecular mechanisms incompletely understood. Most studies thus far were performed in non-standardized human specimens or MU of healthy animal hearts. Our study investigates cardiac remodeling processes in sham-operated healthy rat hearts and in hearts subjected to standardized pathological pressure overload by transverse aortic constriction (TAC) prior to MU by heterotopic heart transplantation (hHTx/MU). Rats underwent sham or TAC surgery. Disease progression was monitored by echocardiography prior to MU by hHTx/MU. Hearts after TAC or TAC combined with hHTx/MU were removed and analyzed by histology, western immunoblot and gene expression analysis. TAC surgery resulted in cardiac hypertrophy and impaired cardiac function. TAC hearts revealed significantly increased cardiac myocyte diameter and mild fibrosis. Expression of hypertrophy associated genes after TAC was higher compared to hearts after hHTx/MU. While cardiac myocyte cell diameter regressed to the level of sham-operated controls in all hearts subjected to hHTx/MU, fibrotic remodeling was significantly exacerbated. Transcription of pro-fibrotic and apoptosis-related genes was markedly augmented in all hearts after hHTx/MU. Sarcomeric proteins involved in excitation-contraction coupling displayed significantly lower phosphorylation levels after TAC and significantly reduced total protein levels after hHTx/MU. Development of myocardial fibrosis, cardiac myocyte atrophy and loss of sarcomeric proteins was observed in all hearts that underwent hHTX/MU regardless of the disease state. These results may help to explain the clinical experience with low rates of LVAD removal due to lack of myocardial recovery.
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Affiliation(s)
- Andreas Schaefer
- Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany. .,DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany. .,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Yvonne Schneeberger
- Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Steven Schulz
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Krasemann
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tessa Werner
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Angelika Piasecki
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Grit Höppner
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Müller
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of General and Interventional Cardiology, University Heart Center, Hamburg, Germany
| | - Karoline Morhenn
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | - Alexander P Schwoerer
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Eschenhagen
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Heimo Ehmke
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hermann Reichenspurner
- Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Justus Stenzig
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Friederike Cuello
- DZHK (German Centre for Cardiovascular Research) partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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30
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Kellermayer D, Smith JE, Granzier H. Titin mutations and muscle disease. Pflugers Arch 2019; 471:673-682. [PMID: 30919088 DOI: 10.1007/s00424-019-02272-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022]
Abstract
The introduction of next-generation sequencing technology has revealed that mutations in the gene that encodes titin (TTN) are linked to multiple skeletal and cardiac myopathies. The most prominent of these myopathies is dilated cardiomyopathy (DCM). Over 60 genes are linked to the etiology of DCM, but by far, the leading cause of DCM is mutations in TTN with truncating variants in TTN (TTNtvs) associated with familial DCM in ∼ 20% of the cases. Titin is a large (3-4 MDa) and abundant protein that forms the third myofilament type of striated muscle where it spans half the sarcomere, from the Z-disk to the M-line. The underlying mechanisms by which titin mutations induce disease are poorly understood and targeted therapies are not available. Here, we review what is known about TTN mutations in muscle disease, with a major focus on DCM. We highlight that exon skipping might provide a possible therapeutic avenue to address diseases that arise from TTNtvs.
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Affiliation(s)
- Dalma Kellermayer
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA.,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA
| | - John E Smith
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA.,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA. .,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA.
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31
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Differences in light scattering between pale and dark beef longissimus thoracis muscles are primarily caused by differences in the myofilament lattice, myofibril and muscle fibre transverse spacings. Meat Sci 2019; 149:96-106. [DOI: 10.1016/j.meatsci.2018.11.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 10/16/2018] [Accepted: 11/05/2018] [Indexed: 01/15/2023]
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32
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Freundt JK, Linke WA. Titin as a force-generating muscle protein under regulatory control. J Appl Physiol (1985) 2018; 126:1474-1482. [PMID: 30521425 DOI: 10.1152/japplphysiol.00865.2018] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Titin has long been recognized as a mechanical protein in muscle cells that has a main function as a molecular spring in the contractile units, the sarcomeres. Recent work suggests that the titin spring contributes to muscle contraction in a more active manner than previously thought. In this review, we highlight this property, specifically the ability of the immunoglobulin-like (Ig) domains of titin to undergo unfolding-refolding transitions when isolated titin molecules or skeletal myofibrils are held at physiological force levels. Folding of titin Ig domains under force is a hitherto unappreciated, putative source of work production in muscle cells, which could work in synergy with the actomyosin system to maximize the energy delivered by a stretched, actively contracting muscle. This review also focuses on the mechanisms shown to modulate titin-based viscoelastic forces in skeletal muscle cells, including chaperone binding, titin oxidation, phosphorylation, Ca2+ binding, and interaction with actin filaments. Along the way, we discuss which of these modulatory mechanisms might contribute to the phenomenon of residual force enhancement relevant for eccentric muscle contractions. Finally, a brief perspective is added on the potential for the alterations in titin-based force to dynamically alter mechano-chemical signaling pathways in the muscle cell. We conclude that titin from skeletal muscle is a determinant of both passive and active tension and a bona fide mechanosensor, whose stiffness is tuned by various independent mechanisms.
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Affiliation(s)
- Johanna K Freundt
- Institute of Physiology II, University of Muenster , Muenster , Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University of Muenster , Muenster , Germany
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33
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Fichna JP, Maruszak A, Żekanowski C. Myofibrillar myopathy in the genomic context. J Appl Genet 2018; 59:431-439. [PMID: 30203143 DOI: 10.1007/s13353-018-0463-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022]
Abstract
Myofibrillar myopathy (MFM) is a group of inherited muscular disorders characterized by myofibril dissolution and abnormal accumulation of degradation products. The diagnosis of muscular disorders based on clinical presentation is difficult due to phenotypic heterogeneity and overlapping symptoms. In addition, precise diagnosis does not always explain the disease etiopathology or the highly variable clinical course even among patients diagnosed with the same type of myopathy. The advent of high-throughput next-generation sequencing (NGS) has provided a successful and cost-effective strategy for identification of novel causative genes in myopathies, including MFM. So far, pathogenic mutations associated with MFM phenotype, including atypical MFM-like cases, have been identified in 17 genes: DES, CRYAB, MYOT, ZASP, FLNC, BAG3, FHL1, TTN, DNAJB6, PLEC, LMNA, ACTA1, HSPB8, KY, PYROXD1, and SQSTM + TIA1 (digenic). Most of these genes are also associated with other forms of muscle diseases. In addition, in many MFM patients, numerous genomic variants in muscle-related genes have been identified. The various myopathies and muscular dystrophies seem to form a single disease continuum; therefore, gene identification in one disease impacts the genetic etiology of the others. In this review, we describe the heterogeneity of the MFM genetic background focusing on the role of rare variants, the importance of whole genome sequencing in the identification of novel disease-associated mutations, and the emerging concept of variant load as the basis of the phenotypic heterogeneity.
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Affiliation(s)
- Jakub Piotr Fichna
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland.
| | - Aleksandra Maruszak
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland
| | - Cezary Żekanowski
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland
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34
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Do Actomyosin Single-Molecule Mechanics Data Predict Mechanics of Contracting Muscle? Int J Mol Sci 2018; 19:ijms19071863. [PMID: 29941816 PMCID: PMC6073448 DOI: 10.3390/ijms19071863] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 12/15/2022] Open
Abstract
In muscle, but not in single-molecule mechanics studies, actin, myosin and accessory proteins are incorporated into a highly ordered myofilament lattice. In view of this difference we compare results from single-molecule studies and muscle mechanics and analyze to what degree data from the two types of studies agree with each other. There is reasonable correspondence in estimates of the cross-bridge power-stroke distance (7–13 nm), cross-bridge stiffness (~2 pN/nm) and average isometric force per cross-bridge (6–9 pN). Furthermore, models defined on the basis of single-molecule mechanics and solution biochemistry give good fits to experimental data from muscle. This suggests that the ordered myofilament lattice, accessory proteins and emergent effects of the sarcomere organization have only minor modulatory roles. However, such factors may be of greater importance under e.g., disease conditions. We also identify areas where single-molecule and muscle data are conflicting: (1) whether force generation is an Eyring or Kramers process with just one major power-stroke or several sub-strokes; (2) whether the myofilaments and the cross-bridges have Hookean or non-linear elasticity; (3) if individual myosin heads slip between actin sites under certain conditions, e.g., in lengthening; or (4) if the two heads of myosin cooperate.
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35
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Four and a half LIM domain protein signaling and cardiomyopathy. Biophys Rev 2018; 10:1073-1085. [PMID: 29926425 DOI: 10.1007/s12551-018-0434-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 06/06/2018] [Indexed: 01/10/2023] Open
Abstract
Four and a half LIM domain (FHL) protein family members, FHL1 and FHL2, are multifunctional proteins that are enriched in cardiac muscle. Although they both localize within the cardiomyocyte sarcomere (titin N2B), they have been shown to have important yet unique functions within the context of cardiac hypertrophy and disease. Studies in FHL1-deficient mice have primarily uncovered mitogen-activated protein kinase (MAPK) scaffolding functions for FHL1 as part of a novel biomechanical stretch sensor within the cardiomyocyte sarcomere, which acts as a positive regulator of pressure overload-mediated cardiac hypertrophy. New data have highlighted a novel role for the serine/threonine protein phosphatase (PP5) as a deactivator of the FHL1-based biomechanical stretch sensor, which has implications in not only cardiac hypertrophy but also heart failure. In contrast, studies in FHL2-deficient mice have primarily uncovered an opposing role for FHL2 as a negative regulator of adrenergic-mediated signaling and cardiac hypertrophy, further suggesting unique functions targeted by FHL proteins in the "stressed" cardiomyocyte. In this review, we provide current knowledge of the role of FHL1 and FHL2 in cardiac muscle as it relates to their actions in cardiac hypertrophy and cardiomyopathy. A specific focus will be to dissect the pathways and protein-protein interactions that underlie FHLs' signaling role in cardiac hypertrophy as well as provide a comprehensive list of FHL mutations linked to cardiac disease, using evidence gained from genetic mouse models and human genetic studies.
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Picard B, Gagaoua M, Al-Jammas M, De Koning L, Valais A, Bonnet M. Beef tenderness and intramuscular fat proteomic biomarkers: muscle type effect. PeerJ 2018; 6:e4891. [PMID: 29892502 PMCID: PMC5994332 DOI: 10.7717/peerj.4891] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/14/2018] [Indexed: 12/22/2022] Open
Abstract
Tenderness and intramuscular fat content are key attributes for beef sensory qualities. Recently some proteomic analysis revealed several proteins which are considered as good biomarkers of these quality traits. This study focuses on the analysis of 20 of these proteins representative of several biological functions: muscle structure and ultrastructure, muscle energetic metabolism, cellular stress and apoptosis. The relative abundance of the proteins was measured by Reverse Phase Protein Array (RPPA) in five muscles known to have different tenderness and intramuscular lipid contents: Longissimus thoracis (LT), Semimembranosus (SM), Rectus abdominis (RA), Triceps brachii (TB) and Semitendinosus (ST). The main results showed a muscle type effect on 16 among the 20 analyzed proteins. They revealed differences in protein abundance depending on the contractile and metabolic properties of the muscles. The RA muscle was the most different by 11 proteins differentially abundant comparatively to the four other muscles. Among these 11 proteins, six were less abundant namely enolase 3 (ENO3), phosphoglucomutase 1 (PGK1), aldolase (ALDOA), myosin heavy chain IIX (MyHC-IIX), fast myosin light chain 1 (MLC1F), triosephosphate isomerase 1 (TPI1) and five more abundant: Heat shock protein (HSP27, HSP70-1A1, αB-crystallin (CRYAB), troponin T slow (TNNT1), and aldolase dehydrogenase 1 (ALDH1A1). Four proteins: HSP40, four and a half LIM domains protein 1 (FHL1), glycogen phosphorylase B (PYGB) and malate dehydrogenase (MDH1) showed the same abundance whatever the muscle. The correlations observed between the 20 proteins in all the five muscles were used to construct a correlation network. The proteins the most connected with the others were in the following order MyHC-IIX, CRYAB, TPI1, PGK1, ALDH1A1, HSP27 and TNNT1. This knowledge is important for understanding the biological functions related to beef tenderness and intramuscular fat content.
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Affiliation(s)
- Brigitte Picard
- Université Clermont Auvergne, INRA, VetAgro Sup, UMR Herbivores, Saint-Genès-Champanelle, France
| | - Mohammed Gagaoua
- Université Clermont Auvergne, INRA, VetAgro Sup, UMR Herbivores, Saint-Genès-Champanelle, France
| | - Marwa Al-Jammas
- Université Clermont Auvergne, INRA, VetAgro Sup, UMR Herbivores, Saint-Genès-Champanelle, France
| | - Leanne De Koning
- Institut Curie Centre de Recherche, Université de recherche PSL, Plateforme RPPA, Paris, France
| | - Albéric Valais
- S.I.C.A. Rouge des Prés, Domaines des rues, Chenillé-Champteussé, France
| | - Muriel Bonnet
- Université Clermont Auvergne, INRA, VetAgro Sup, UMR Herbivores, Saint-Genès-Champanelle, France
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Hopf AE, Andresen C, Kötter S, Isić M, Ulrich K, Sahin S, Bongardt S, Röll W, Drove F, Scheerer N, Vandekerckhove L, De Keulenaer GW, Hamdani N, Linke WA, Krüger M. Diabetes-Induced Cardiomyocyte Passive Stiffening Is Caused by Impaired Insulin-Dependent Titin Modification and Can Be Modulated by Neuregulin-1. Circ Res 2018; 123:342-355. [PMID: 29760016 DOI: 10.1161/circresaha.117.312166] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 05/05/2018] [Accepted: 05/11/2018] [Indexed: 12/17/2022]
Abstract
RATIONALE Increased titin-dependent cardiomyocyte tension is a hallmark of heart failure with preserved ejection fraction associated with type-2 diabetes mellitus. However, the insulin-related signaling pathways that modify titin-based cardiomyocyte tension, thereby contributing to modulation of diastolic function, are largely unknown. OBJECTIVE We aimed to determine how impaired insulin signaling affects titin expression and phosphorylation and thus increases passive cardiomyocyte tension, and whether metformin or neuregulin-1 (NRG-1) can correct disturbed titin modifications and increased titin-based stiffness. METHODS AND RESULTS We used cardiac biopsies from human diabetic (n=23) and nondiabetic patients (n=19), cultured rat cardiomyocytes, left ventricular tissue from apolipoprotein E-deficient mice with streptozotocin-induced diabetes mellitus (n=12-22), and ZSF1 (obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid) rats (n=5-6) and analyzed insulin-dependent signaling pathways that modulate titin phosphorylation. Titin-based passive tension was measured using permeabilized cardiomyocytes. In human diabetic hearts, we detected titin hypophosphorylation at S4099 and hyperphosphorylation at S11878, suggesting altered activity of protein kinases; cardiomyocyte passive tension was significantly increased. When applied to cultured cardiomyocytes, insulin and metformin increased titin phosphorylation at S4010, S4099, and S11878 via enhanced ERK1/2 (extracellular signal regulated kinase 1/2) and PKCα (protein kinase Cα) activity; NRG-1 application enhanced ERK1/2 activity but reduced PKCα activity. In apolipoprotein E-deficient mice, chronic treatment of streptozotocin-induced diabetes mellitus with NRG-1 corrected titin phosphorylation via increased PKG (protein kinase G) and ERK1/2 activity and reduced PKCα activity, which reversed the diabetes mellitus-associated changes in titin-based passive tension. Acute application of NRG-1 to obese ZSF1 rats with type-2 diabetes mellitus reduced end-diastolic pressure. CONCLUSIONS Mechanistically, we found that impaired cGMP-PKG signaling and elevated PKCα activity are key modulators of titin-based cardiomyocyte stiffening in diabetic hearts. We conclude that by restoring normal kinase activities of PKG, ERK1/2, and PKCα, and by reducing cardiomyocyte passive tension, chronic NRG-1 application is a promising approach to modulate titin properties in heart failure with preserved ejection fraction associated with type-2 diabetes mellitus.
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Affiliation(s)
- Anna-Eliane Hopf
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Christian Andresen
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Sebastian Kötter
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Małgorzata Isić
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Kamila Ulrich
- Department of Systems Physiology, Ruhr-University Bochum, Germany (K.U., N.H.)
| | - Senem Sahin
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Sabine Bongardt
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Wilhelm Röll
- Department of Cardiovascular Surgery, University Clinic Bonn, Germany (W.R.)
| | - Felicitas Drove
- Bayer AG, Drug Discovery, Pharmaceuticals, Wuppertal, Germany (F.D., N.S.)
| | - Nina Scheerer
- Bayer AG, Drug Discovery, Pharmaceuticals, Wuppertal, Germany (F.D., N.S.)
| | - Leni Vandekerckhove
- Department of Pharmaceutical Sciences, Laboratory of Physiopharmacology, Campus Drie Eiken, University of Antwerp, Belgium (L.V., G.W.D.)
| | - Gilles W De Keulenaer
- Department of Pharmaceutical Sciences, Laboratory of Physiopharmacology, Campus Drie Eiken, University of Antwerp, Belgium (L.V., G.W.D.)
| | - Nazha Hamdani
- Department of Systems Physiology, Ruhr-University Bochum, Germany (K.U., N.H.)
| | - Wolfgang A Linke
- Institute of Physiology II, University of Munster, Germany (W.A.L.)
| | - Martina Krüger
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
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Alogna A, Schwarzl M, Manninger M, Hamdani N, Zirngast B, Kloth B, Steendijk P, Verderber J, Zweiker D, Westermann D, Blankenberg S, Maechler H, Tschöpe C, Linke WA, Marsche G, Pieske BM, Post H. Acute stimulation of the soluble guanylate cyclase does not impact on left ventricular capacitance in normal and hypertrophied porcine hearts in vivo. Am J Physiol Heart Circ Physiol 2018; 315:H669-H680. [PMID: 29727215 DOI: 10.1152/ajpheart.00510.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Experimental data indicate that stimulation of the nitric oxide-soluble guanylate cyclase(sGC)-cGMP-PKG pathway can increase left ventricular (LV) capacitance via phosphorylation of the myofilamental protein titin. We aimed to test whether acute pharmacological sGC stimulation with BAY 41-8543 would increase LV capacitance via titin phosphorylation in healthy and deoxycorticosteroneacetate (DOCA)-induced hypertensive pigs. Nine healthy Landrace pigs and 7 pigs with DOCA-induced hypertension and LV concentric hypertrophy were acutely instrumented to measure LV end-diastolic pressure-volume relationships (EDPVRs) at baseline and during intravenous infusion of BAY 41-8543 (1 and 3 μg·kg-1·min-1 for 30 min, respectively). Separately, in seven healthy and six DOCA pigs, transmural LV biopsies were harvested from the beating heart to measure titin phosphorylation during BAY 41-8543 infusion. LV EDPVRs before and during BAY 41-8543 infusion were superimposable in both healthy and DOCA-treated pigs, whereas mean aortic pressure decreased by 20-30 mmHg in both groups. Myocardial titin phosphorylation was unchanged in healthy pigs, but total and site-specific (Pro-Glu-Val-Lys and N2-Bus domains) titin phosphorylation was increased in DOCA-treated pigs. Bicoronary nitroglycerin infusion in healthy pigs ( n = 5) induced a rightward shift of the LV EDPVR, demonstrating the responsiveness of the pathway in this model. Acute systemic sGC stimulation with the sGC stimulator BAY 41-8543 did not recruit an LV preload reserve in both healthy and hypertrophied LV porcine myocardium, although it increased titin phosphorylation in the latter group. Thus, increased titin phosphorylation is not indicative of increased in vivo LV capacitance. NEW & NOTEWORTHY We demonstrate that acute pharmacological stimulation of soluble guanylate cyclase does not increase left ventricular compliance in normal and hypertrophied porcine hearts. Effects of long-term soluble guanylate cyclase stimulation with oral compounds in disease conditions associated with lowered myocardial cGMP levels, i.e., heart failure with preserved ejection fraction, remain to be investigated.
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Affiliation(s)
- Alessio Alogna
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Berlin Institute of Health , Berlin , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Berlin, Berlin, Germany
| | - Michael Schwarzl
- Department of General and Interventional Cardiology, University Heart Center Hamburg-Eppendorf , Hamburg , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Hamburg/Kiel/Lübeck, Hamburg , Germany
| | - Martin Manninger
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz , Graz , Austria
| | - Nazha Hamdani
- Institute of Physiology II, University of Muenster , Muenster , Germany
| | - Birgit Zirngast
- Department of Cardiothoracic Surgery, Medical University of Graz , Graz , Austria
| | - Benjamin Kloth
- Department of Cardiovascular Surgery, University Heart Center Hamburg-Eppendorf , Hamburg , Germany
| | - Paul Steendijk
- Department of Cardiology, Leiden University Medical Center , Leiden , The Netherlands
| | - Jochen Verderber
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz , Graz , Austria
| | - David Zweiker
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz , Graz , Austria
| | - Dirk Westermann
- Department of General and Interventional Cardiology, University Heart Center Hamburg-Eppendorf , Hamburg , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Hamburg/Kiel/Lübeck, Hamburg , Germany
| | - Stefan Blankenberg
- Department of General and Interventional Cardiology, University Heart Center Hamburg-Eppendorf , Hamburg , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Hamburg/Kiel/Lübeck, Hamburg , Germany
| | - Heinrich Maechler
- Department of Cardiothoracic Surgery, Medical University of Graz , Graz , Austria
| | - Carsten Tschöpe
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Berlin Institute of Health , Berlin , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Berlin, Berlin, Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University of Muenster , Muenster , Germany
| | - Gunther Marsche
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz , Graz , Austria
| | - Burkert M Pieske
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Berlin Institute of Health , Berlin , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Berlin, Berlin, Germany
| | - Heiner Post
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Berlin Institute of Health , Berlin , Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung E.V.-Partner Site Berlin, Berlin, Germany
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Guo W, Zhu C, Yin Z, Wang Q, Sun M, Cao H, Greaser ML. Splicing Factor RBM20 Regulates Transcriptional Network of Titin Associated and Calcium Handling Genes in The Heart. Int J Biol Sci 2018; 14:369-380. [PMID: 29725258 PMCID: PMC5930469 DOI: 10.7150/ijbs.24117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/27/2018] [Indexed: 01/28/2023] Open
Abstract
RNA binding motif 20 (RBM20) regulates pre-mRNA splicing of over thirty genes, among which titin is a major target. With RBM20 expression, titin expresses a larger isoform at fetal stage to a smaller isoform at adult resulting from alternative splicing, while, without RBM20, titin expresses exclusively a larger isoform throughout all ages. In addition to splicing regulation, it is unknown whether RBM20 also regulates gene expression. In this study, we employed Rbm20 knockout rats to investigate gene expression profile using Affymetrix expression array. We compared wild type to Rbm20 knockout at day1, 20 and 49. Bioinformatics analysis showed RBM20 regulates fewer genes expression at younger age and more at older age and commonly expressed genes have the same trends. GSEA indicated up-regulated genes are associated with heart failure. We examined titin binding partners. All titin direct binding partners are up-regulated and their increased expression is associated with dilated cardiomyopathy. Particularly, we found that genes involving calcium handling and muscle contraction are changed by RBM20. Intracellular calcium level measurement with individual cardiomyocytes further confirmed that changes of these proteins impact calcium handling. Selected genes from titin binding partners and calcium handling were validated with QPCR and western blotting. These data demonstrate that RBM20 regulates gene splicing as well as gene expression. Altered gene expression by RBM20 influences protein-protein interaction, calcium releasing and thus muscle contraction. Our results first reported gene expression impacted by RBM20 with heart maturation, and provided new insights into the role of RBM20 in the progression of heart failure.
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Affiliation(s)
- Wei Guo
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Chaoqun Zhu
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Zhiyong Yin
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Department of Cardiology, Xi Jing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Qiurong Wang
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Mingming Sun
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Huojun Cao
- Iowa Institute for Oral Health Research, College of Dentistry.,Craniofacial Anomalies Research Center, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Marion L Greaser
- Animal Science, University of Wisconsin-Madison, Madison, WI 53705, USA
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Protein phosphatase 5 regulates titin phosphorylation and function at a sarcomere-associated mechanosensor complex in cardiomyocytes. Nat Commun 2018; 9:262. [PMID: 29343782 PMCID: PMC5772059 DOI: 10.1038/s41467-017-02483-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 12/04/2017] [Indexed: 12/14/2022] Open
Abstract
Serine/threonine protein phosphatase 5 (PP5) is ubiquitously expressed in eukaryotic cells; however, its function in cardiomyocytes is unknown. Under basal conditions, PP5 is autoinhibited, but enzymatic activity rises upon binding of specific factors, such as the chaperone Hsp90. Here we show that PP5 binds and dephosphorylates the elastic N2B-unique sequence (N2Bus) of titin in cardiomyocytes. Using various binding and phosphorylation tests, cell-culture manipulation, and transgenic mouse hearts, we demonstrate that PP5 associates with N2Bus in vitro and in sarcomeres and is antagonistic to several protein kinases, which phosphorylate N2Bus and lower titin-based passive tension. PP5 is pathologically elevated and likely contributes to hypo-phosphorylation of N2Bus in failing human hearts. Furthermore, Hsp90-activated PP5 interacts with components of a sarcomeric, N2Bus-associated, mechanosensor complex, and blocks mitogen-activated protein-kinase signaling in this complex. Our work establishes PP5 as a compartmentalized, well-controlled phosphatase in cardiomyocytes, which regulates titin properties and kinase signaling at the myofilaments. Protein phosphatase 5 (PP5) is expressed in many cell types but its role in cardiomyocytes is unknown. Here the authors show that PP5 binds and dephosphorylates elastic titin in cardiac sarcomeres, and that PP5 is increased in heart failure, reducing cardiomyocyte compliance.
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Ehsan M, Jiang H, L Thomson K, Gehmlich K. When signalling goes wrong: pathogenic variants in structural and signalling proteins causing cardiomyopathies. J Muscle Res Cell Motil 2017; 38:303-316. [PMID: 29119312 PMCID: PMC5742121 DOI: 10.1007/s10974-017-9487-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/28/2017] [Indexed: 12/20/2022]
Abstract
Cardiomyopathies are a diverse group of cardiac disorders with distinct phenotypes, depending on the proteins and pathways affected. A substantial proportion of cardiomyopathies are inherited and those will be the focus of this review article. With the wide application of high-throughput sequencing in the practice of clinical genetics, the roles of novel genes in cardiomyopathies are recognised. Here, we focus on a subgroup of cardiomyopathy genes [TTN, FHL1, CSRP3, FLNC and PLN, coding for Titin, Four and a Half LIM domain 1, Muscle LIM Protein, Filamin C and Phospholamban, respectively], which, despite their diverse biological functions, all have important signalling functions in the heart, suggesting that disturbances in signalling networks can contribute to cardiomyopathies.
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Affiliation(s)
- Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Kate L Thomson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK.
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Franssen C, Kole J, Musters R, Hamdani N, Paulus WJ. α-B Crystallin Reverses High Diastolic Stiffness of Failing Human Cardiomyocytes. Circ Heart Fail 2017; 10:e003626. [PMID: 28242778 DOI: 10.1161/circheartfailure.116.003626] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/23/2017] [Indexed: 01/09/2023]
Abstract
BACKGROUND Cardiomyocytes with a less distensible titin and interstitial collagen contribute to the high diastolic stiffness of failing myocardium. Their relative contributions and mechanisms underlying loss of titin distensibility were assessed in failing human hearts. METHODS AND RESULTS Left ventricular tissue was procured in patients with aortic stenosis (AS, n=9) and dilated cardiomyopathy (DCM, n=6). Explanted donor hearts (n=8) served as controls. Stretches were performed in myocardial strips, and an extraction protocol differentiated between passive tension (Fpassive) attributable to cardiomyocytes or to collagen. Fpassive-cardiomyocytes was higher in AS and DCM at shorter muscle lengths, whereas Fpassive-collagen was higher in AS at longer muscle lengths and in DCM at shorter and longer muscle lengths. Cardiomyocytes were stretched to investigate titin distensibility. Cardiomyocytes were incubated with alkaline phosphatase, subsequently reassessed after a period of prestretch and finally treated with the heat shock protein α-B crystallin. Alkaline phosphatase shifted the Fpassive-sarcomere length relation upward only in donor. Prestretch shifted the Fpassive-sarcomere length relation further upward in donor and upward in AS and DCM. α-B crystallin shifted the Fpassive-sarcomere length relation downward to baseline in donor and to lower than baseline in AS and DCM. In failing myocardium, confocal laser microscopy revealed α-B crystallin in subsarcolemmal aggresomes. CONCLUSIONS High cardiomyocyte stiffness contributed to stiffness of failing human myocardium because of reduced titin distensibility. The latter resulted from an absent stiffness-lowering effect of baseline phosphorylation and from titin aggregation. High cardiomyocyte stiffness was corrected by α-B crystallin probably through relief of titin aggregation.
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Affiliation(s)
- Constantijn Franssen
- From the Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (C.F., J.K., R.M., N.H., W.J.P.); and Department of Cardiovascular Physiology, Ruhr University Bochum, Germany (N.H.)
| | - Jeroen Kole
- From the Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (C.F., J.K., R.M., N.H., W.J.P.); and Department of Cardiovascular Physiology, Ruhr University Bochum, Germany (N.H.)
| | - René Musters
- From the Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (C.F., J.K., R.M., N.H., W.J.P.); and Department of Cardiovascular Physiology, Ruhr University Bochum, Germany (N.H.)
| | - Nazha Hamdani
- From the Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (C.F., J.K., R.M., N.H., W.J.P.); and Department of Cardiovascular Physiology, Ruhr University Bochum, Germany (N.H.)
| | - Walter J Paulus
- From the Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (C.F., J.K., R.M., N.H., W.J.P.); and Department of Cardiovascular Physiology, Ruhr University Bochum, Germany (N.H.).
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Tampering with springs: phosphorylation of titin affecting the mechanical function of cardiomyocytes. Biophys Rev 2017; 9:225-237. [PMID: 28510118 PMCID: PMC5498327 DOI: 10.1007/s12551-017-0263-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/26/2017] [Indexed: 12/17/2022] Open
Abstract
Reversible post-translational modifications of various cardiac proteins regulate the mechanical properties of the cardiomyocytes and thus modulate the contractile performance of the heart. The giant protein titin forms a continuous filament network in the sarcomeres of striated muscle cells, where it determines passive tension development and modulates active contraction. These mechanical properties of titin are altered through post-translational modifications, particularly phosphorylation. Titin contains hundreds of potential phosphorylation sites, the functional relevance of which is only beginning to emerge. Here, we provide a state-of-the-art summary of the phosphorylation sites in titin, with a particular focus on the elastic titin spring segment. We discuss how phosphorylation at specific amino acids can reduce or increase the stretch-induced spring force of titin, depending on where the spring region is phosphorylated. We also review which protein kinases phosphorylate titin and how this phosphorylation affects titin-based passive tension in cardiomyocytes. A comprehensive overview is provided of studies that have measured altered titin phosphorylation and titin-based passive tension in myocardial samples from human heart failure patients and animal models of heart disease. As our understanding of the broader implications of phosphorylation in titin progresses, this knowledge could be used to design targeted interventions aimed at reducing pathologically increased titin stiffness in patients with stiff hearts.
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Abstract
Striated cardiac and skeletal muscles play very different roles in the body, but they are similar at the molecular level. In particular, contraction, regardless of the type of muscle, is a precise and complex process involving the integral protein myofilaments and their associated regulatory components. The smallest functional unit of muscle contraction is the sarcomere. Within the sarcomere can be found a sophisticated ensemble of proteins associated with the thick filaments (myosin, myosin binding protein-C, titin, and obscurin) and thin myofilaments (actin, troponin, tropomyosin, nebulin, and nebulette). These parallel thick and thin filaments slide across one another, pulling the two ends of the sarcomere together to regulate contraction. More specifically, the regulation of both timing and force of contraction is accomplished through an intricate network of intra- and interfilament interactions belonging to each myofilament. This review introduces the sarcomere proteins involved in striated muscle contraction and places greater emphasis on the more recently identified and less well-characterized myofilaments: cardiac myosin binding protein-C, titin, nebulin, and obscurin. © 2017 American Physiological Society. Compr Physiol 7:675-692, 2017.
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Affiliation(s)
- Brian Leei Lin
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
| | - Taejeong Song
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Hinze F, Dieterich C, Radke MH, Granzier H, Gotthardt M. Reducing RBM20 activity improves diastolic dysfunction and cardiac atrophy. J Mol Med (Berl) 2016; 94:1349-1358. [PMID: 27889803 PMCID: PMC5143357 DOI: 10.1007/s00109-016-1483-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/09/2016] [Accepted: 11/01/2016] [Indexed: 01/14/2023]
Abstract
Abstract Impaired diastolic filling is a main contributor to heart failure with preserved ejection fraction (HFpEF), a syndrome with increasing prevalence and no treatment. Both collagen and the giant sarcomeric protein titin determine diastolic function. Since titin’s elastic properties can be adjusted physiologically, we evaluated titin-based stiffness as a therapeutic target. We adjusted RBM20-dependent cardiac isoform expression in the titin N2B knockout mouse with increased ventricular stiffness. A ~50 % reduction of RBM20 activity does not only maintain cardiac filling in diastole but also ameliorates cardiac atrophy and thus improves cardiac function in the N2B-deficient heart. Reduced RBM20 activity partially normalized gene expression related to muscle development and fatty acid metabolism. The adaptation of cardiac growth was related to hypertrophy signaling via four-and-a-half lim-domain proteins (FHLs) that translate mechanical input into hypertrophy signals. We provide a novel link between cardiac isoform expression and trophic signaling via FHLs and suggest cardiac splicing as a therapeutic target in diastolic dysfunction. Key message Increasing the length of titin isoforms improves ventricular filling in heart disease. FHL proteins are regulated via RBM20 and adapt cardiac growth. RBM20 is a therapeutic target in diastolic dysfunction.
Electronic supplementary material The online version of this article (doi:10.1007/s00109-016-1483-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Florian Hinze
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Christoph Dieterich
- Klaus Tschira Institute for Integrative Computational Cardiology and Department of Cardiology, Angiology, and Pneumology, Heidelberg University, Analysezentrum III, INF 669, 69120, Heidelberg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Heidelberg, Heidelberg, Germany
| | - Michael H Radke
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Arizona Health Sciences Center, 1501 N. Campbell, PO Box 245051, Tucson, AZ, 85724, USA
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany. .,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany.
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Phosphorylating Titin's Cardiac N2B Element by ERK2 or CaMKIIδ Lowers the Single Molecule and Cardiac Muscle Force. Biophys J 2016; 109:2592-2601. [PMID: 26682816 DOI: 10.1016/j.bpj.2015.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 12/28/2022] Open
Abstract
Titin is a large filamentous protein that is responsible for the passive force of the cardiac sarcomere. Titin's force is generated by its I-band region, which includes the cardiac-specific N2B element. The N2B element consists of three immunoglobulin domains, two small unique sequence insertions, and a large 575-residue unique sequence, the N2B-Us. Posttranslational modifications of the N2B element are thought to regulate passive force, but the underlying mechanisms are unknown. Increased passive-force levels characterize diastolic stiffening in heart-failure patients, and it is critical to understand the underlying molecular mechanisms and identify therapeutic targets. Here, we used single-molecule force spectroscopy to study the mechanical effects of the kinases calcium/calmodulin-dependent protein kinase II delta (CaMKIIδ) and extracellular signal-regulated kinase 2 (ERK2) on the single-molecule mechanics of the N2B element. Both CaMKIIδ and ERK2 were found to phosphorylate the N2B element, and single-molecule force spectroscopy revealed an increase in the persistence length (Lp) of the molecule, indicating that the bending rigidity of the molecule was increased. Experiments performed under oxidizing conditions and with a recombinant N2B element that had a simplified domain composition provided evidence that the Lp increase requires the N2B-Us of the N2B element. Mechanical experiments were also performed on skinned myocardium before and after phosphorylation. The results revealed a large (∼30%) passive force reduction caused by CaMKIIδ and a much smaller (∼6%) reduction caused by ERK2. These findings support the notion that the important kinases ERK2 and CaMKIIδ can alter the passive force of myocytes in the heart (although CaMKIIδ appears to be more potent) during physiological and pathophysiological states.
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Bull M, Methawasin M, Strom J, Nair P, Hutchinson K, Granzier H. Alternative Splicing of Titin Restores Diastolic Function in an HFpEF-Like Genetic Murine Model (TtnΔIAjxn). Circ Res 2016; 119:764-72. [PMID: 27470639 DOI: 10.1161/circresaha.116.308904] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/28/2016] [Indexed: 12/15/2022]
Abstract
RATIONALE Patients with heart failure with preserved ejection fraction (HFpEF) experience elevated filling pressures and reduced ventricular compliance. The splicing factor RNA-binding motif 20 (RBM20) regulates the contour length of titin's spring region and thereby determines the passive stiffness of cardiomyocytes. Inhibition of RBM20 leads to super compliant titin isoforms (N2BAsc) that reduce passive stiffness. OBJECTIVE To determine the therapeutic potential of upregulating compliant titin isoforms in an HFpEF-like state in the mouse. METHODS AND RESULTS Constitutive and inducible cardiomyocyte-specific RBM20-inhibited mice were produced on a Ttn(ΔIAjxn) background to assess the effect of upregulating compliant titin at the cellular and organ levels. Genetic deletion of the I-band-A-band junction (IAjxn) in titin increases strain on the spring region and causes a HFpEF-like syndrome in the mouse without pharmacological or surgical intervention. The increased strain represents a mechanical analog of deranged post-translational modification of titin that results in increased passive myocardial stiffness in patients with HFpEF. On inhibition of RBM20 in Ttn(ΔIAjxn) mice, compliant titin isoforms were expressed, diastolic function was normalized, exercise performance was improved, and pathological hypertrophy was attenuated. CONCLUSIONS We report for the first time a benefit from upregulating compliant titin isoforms in a murine model with HFpEF-like symptoms. Constitutive and inducible RBM20 inhibition improves diastolic function resulting in greater tolerance to exercise. No effective therapies exists for treating this pervasive syndrome; therefore, our data on RBM20 inhibition are clinically significant.
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Affiliation(s)
- Mathew Bull
- From the Department of Cellular and Molecular Medicine (M.B., M.M., J.S., P.N., K.H., H.G.) and Sarver Molecular Cardiovascular Research Program (M.B., M.M., J.S., P.N., K.H., H.G.), University of Arizona, Tucson
| | - Mei Methawasin
- From the Department of Cellular and Molecular Medicine (M.B., M.M., J.S., P.N., K.H., H.G.) and Sarver Molecular Cardiovascular Research Program (M.B., M.M., J.S., P.N., K.H., H.G.), University of Arizona, Tucson
| | - Joshua Strom
- From the Department of Cellular and Molecular Medicine (M.B., M.M., J.S., P.N., K.H., H.G.) and Sarver Molecular Cardiovascular Research Program (M.B., M.M., J.S., P.N., K.H., H.G.), University of Arizona, Tucson
| | - Pooja Nair
- From the Department of Cellular and Molecular Medicine (M.B., M.M., J.S., P.N., K.H., H.G.) and Sarver Molecular Cardiovascular Research Program (M.B., M.M., J.S., P.N., K.H., H.G.), University of Arizona, Tucson
| | - Kirk Hutchinson
- From the Department of Cellular and Molecular Medicine (M.B., M.M., J.S., P.N., K.H., H.G.) and Sarver Molecular Cardiovascular Research Program (M.B., M.M., J.S., P.N., K.H., H.G.), University of Arizona, Tucson
| | - Henk Granzier
- From the Department of Cellular and Molecular Medicine (M.B., M.M., J.S., P.N., K.H., H.G.) and Sarver Molecular Cardiovascular Research Program (M.B., M.M., J.S., P.N., K.H., H.G.), University of Arizona, Tucson.
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Rodrigues PG, Leite-Moreira AF, Falcão-Pires I. Myocardial reverse remodeling: how far can we rewind? Am J Physiol Heart Circ Physiol 2016; 310:H1402-22. [PMID: 26993225 DOI: 10.1152/ajpheart.00696.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 03/04/2016] [Indexed: 12/19/2022]
Abstract
Heart failure (HF) is a systemic disease that can be divided into HF with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF). HFpEF accounts for over 50% of all HF patients and is typically associated with high prevalence of several comorbidities, including hypertension, diabetes mellitus, pulmonary hypertension, obesity, and atrial fibrillation. Myocardial remodeling occurs both in HFrEF and HFpEF and it involves changes in cardiac structure, myocardial composition, and myocyte deformation and multiple biochemical and molecular alterations that impact heart function and its reserve capacity. Understanding the features of myocardial remodeling has become a major objective for limiting or reversing its progression, the latter known as reverse remodeling (RR). Research on HFrEF RR process is broader and has delivered effective therapeutic strategies, which have been employed for some decades. However, the RR process in HFpEF is less clear partly due to the lack of information on HFpEF pathophysiology and to the long list of failed standard HF therapeutics strategies in these patient's outcomes. Nevertheless, new proteins, protein-protein interactions, and signaling pathways are being explored as potential new targets for HFpEF remodeling and RR. Here, we review recent translational and clinical research in HFpEF myocardial remodeling to provide an overview on the most important features of RR, comparing HFpEF with HFrEF conditions.
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Affiliation(s)
- Patrícia G Rodrigues
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Universidade do Porto, Porto, Portugal
| | - Adelino F Leite-Moreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Universidade do Porto, Porto, Portugal
| | - Inês Falcão-Pires
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Universidade do Porto, Porto, Portugal
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Franssen C, González Miqueo A. The role of titin and extracellular matrix remodelling in heart failure with preserved ejection fraction. Neth Heart J 2016; 24:259-67. [PMID: 26886920 PMCID: PMC4796057 DOI: 10.1007/s12471-016-0812-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) is characterised by a high incidence of metabolic comorbidities that share the potential to induce both systemic and coronary microvascular inflammation and oxidative stress. These pathophysiological alterations contribute to increased passive stiffness of the myocardium and to diastolic dysfunction, both hallmarks of HFpEF. Passive myocardial stiffness depends mainly on two components: the extracellular matrix (ECM) and the cardiomyocytes. Quantitative and qualitative changes in collagen metabolism leading to myocardial fibrosis determine the ECM-based stiffness of the myocardium. Different noninvasive diagnostic tools to assess myocardial fibrosis are being developed, some of which have demonstrated to correlate with clinical status and prognosis. Cardiomyocytes mainly alter the passive stiffness through alterations in the giant myofilament titin, which serves as a spring. By modifying its phosphorylation state or by direct oxidative effects, titin determines cardiomyocyte-based passive stiffness. Probably the relative importance of cardiomyocyte-based changes is more important in the beginning of the disease, whereas ECM-based changes become more prominent in the more advanced stages. The present review focuses on these changes in ECM and cardiomyocytes in HFpEF and their potential prognostic and therapeutic implications.
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Affiliation(s)
- C Franssen
- ICaR-VU, VU University Medical Center, Van der Boechorststraat 7, 1081, BT Amsterdam, The Netherlands.
| | - A González Miqueo
- Center for Applied Medical Research, University of Navarra, Program of Cardiovascular Diseases, Pamplona, Spain
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Krüger M, Kötter S. Titin, a Central Mediator for Hypertrophic Signaling, Exercise-Induced Mechanosignaling and Skeletal Muscle Remodeling. Front Physiol 2016; 7:76. [PMID: 26973541 PMCID: PMC4771757 DOI: 10.3389/fphys.2016.00076] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/15/2016] [Indexed: 01/09/2023] Open
Abstract
Titin is a giant scaffold protein with multiple functions in striated muscle physiology. Due to the elastic I-band domains and the filament-like integration in the half-sarcomere titin is an important factor for sarcomere assembly and serves as an adaptable molecular spring that determines myofilament distensibility. Protein-interactions e.g., with muscle ankyrin repeat proteins or muscle LIM-protein link titin to hypertrophic signaling and via p62 and Muscle Ring Finger proteins to mechanisms that control protein quality control. This review summarizes our current knowledge on titin as a central node for exercise-induced mechanosignaling and remodeling and further highlights the pathophysiological implications.
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Affiliation(s)
- Martina Krüger
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf Düsseldorf, Germany
| | - Sebastian Kötter
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf Düsseldorf, Germany
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