1
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Douglas CM, Bird JE, Kopinke D, Esser KA. An optimized approach to study nanoscale sarcomere structure utilizing super-resolution microscopy with nanobodies. PLoS One 2024; 19:e0300348. [PMID: 38687705 PMCID: PMC11060602 DOI: 10.1371/journal.pone.0300348] [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: 11/06/2023] [Accepted: 02/23/2024] [Indexed: 05/02/2024] Open
Abstract
The sarcomere is the fundamental contractile unit in skeletal muscle, and the regularity of its structure is critical for function. Emerging data demonstrates that nanoscale changes to the regularity of sarcomere structure can affect the overall function of the protein dense ~2μm sarcomere. Further, sarcomere structure is implicated in many clinical conditions of muscle weakness. However, our understanding of how sarcomere structure changes in disease, especially at the nanoscale, has been limited in part due to the inability to robustly detect and measure at sub-sarcomere resolution. We optimized several methodological steps and developed a robust pipeline to analyze sarcomere structure using structured illumination super-resolution microscopy in conjunction with commercially-available and fluorescently-conjugated Variable Heavy-Chain only fragment secondary antibodies (nanobodies), and achieved a significant increase in resolution of z-disc width (353nm vs. 62nm) compared to confocal microscopy. The combination of these methods provides a unique approach to probe sarcomere protein localization at the nanoscale and may prove advantageous for analysis of other cellular structures.
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Affiliation(s)
- Collin M. Douglas
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States of America
| | - Jonathan E. Bird
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Daniel Kopinke
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Karyn A. Esser
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States of America
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2
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Perrin A, Métay C, Savarese M, Ben Yaou R, Demidov G, Nelson I, Solé G, Péréon Y, Bertini ES, Fattori F, D'Amico A, Ricci F, Ginsberg M, Seferian A, Boespflug-Tanguy O, Servais L, Chapon F, Lagrange E, Gaudon K, Bloch A, Ghanem R, Guyant-Maréchal L, Johari M, Van Goethem C, Fardeau M, Morales RJ, Genetti CA, Marttila M, Koenig M, Beggs AH, Udd B, Bonne G, Cossée M. Titin copy number variations associated with dominant inherited phenotypes. J Med Genet 2024; 61:369-377. [PMID: 37935568 PMCID: PMC10957311 DOI: 10.1136/jmg-2023-109473] [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: 06/22/2023] [Accepted: 10/18/2023] [Indexed: 11/09/2023]
Abstract
BACKGROUND Titinopathies are caused by mutations in the titin gene (TTN). Titin is the largest known human protein; its gene has the longest coding phase with 364 exons. Titinopathies are very complex neuromuscular pathologies due to the variable age of onset of symptoms, the great diversity of pathological and muscular impairment patterns (cardiac, skeletal muscle or mixed) and both autosomal dominant and recessive modes of transmission. Until now, only few CNVs in TTN have been reported without clear genotype-phenotype associations. METHODS Our study includes eight families with dominant titinopathies. We performed next-generation sequencing or comparative genomic hybridisation array analyses and found CNVs in the TTN gene. We characterised these CNVs by RNA sequencing (RNAseq) analyses in six patients' muscles and performed genotype-phenotype inheritance association study by combining the clinical and biological data of these eight families. RESULTS Seven deletion-type CNVs in the TTN gene were identified among these families. Genotype and RNAseq results showed that five deletions do not alter the reading frame and one is out-of-reading frame. The main phenotype identified was distal myopathy associated with contractures. The analysis of morphological, clinical and genetic data and imaging let us draw new genotype-phenotype associations of titinopathies. CONCLUSION Identifying TTN CNVs will further increase diagnostic sensitivity in these complex neuromuscular pathologies. Our cohort of patients enabled us to identify new deletion-type CNVs in the TTN gene, with unexpected autosomal dominant transmission. This is valuable in establishing new genotype-phenotype associations of titinopathies, mainly distal myopathy in most of the patients.
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Affiliation(s)
- Aurélien Perrin
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Corinne Métay
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Marco Savarese
- Tampere Neuromuscular Center, Folkhälsan Research Center, Helsinki, Finland
| | - Rabah Ben Yaou
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - German Demidov
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tubingen, Germany
| | - Isabelle Nelson
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Guilhem Solé
- CHU de Bordeaux, AOC National Reference Center for Neuromuscular Disorders, Bordeaux, France
| | - Yann Péréon
- Department of Clinical Neurophysiology, Reference Centre for Neuromuscular Diseases AOC, Filnemus, Euro-NMD, CHU Nantes, Nantes Université, Place Alexis-Ricordeau, Nantes, France
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children Research Hospital, IRCCS, Rome, Italy
| | - Fabiana Fattori
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children Research Hospital, IRCCS, Rome, Italy
| | - Adele D'Amico
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children Research Hospital, IRCCS, Rome, Italy
| | - Federica Ricci
- Division of Child and Adolescent Neuropsychiatry, University of Turin, Turin, Italy
| | - Mira Ginsberg
- Department of Pediatric Neurology, Wolfson Medical Center, Holon, Israel
| | | | - Odile Boespflug-Tanguy
- Institut I-MOTION, Hôpital Armand Trousseau, Paris, France
- UMR 1141, INSERM, NeuroDiderot Université Paris Cité and APHP, Neuropédiatrie, French Reference Center for Leukodystrophies, LEUKOFRANCE, Hôpital Robert Debré, Paris, France
| | - Laurent Servais
- Institut I-MOTION, Hôpital Armand Trousseau, Paris, France
- MDUK Oxford Neuromuscular Centre & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
- Neuromuscular Reference Center, Division of Paediatrics, University and Hospital University of Liège, Liège, Belgium
| | - Françoise Chapon
- Département de pathologie, Centre de Compétence des Maladies Neuromusculaires, Centre Hospitalier Universitaire de Caen, Caen, France
| | - Emmeline Lagrange
- Centre de Compétences des Maladies Neuro Musculaires, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France
| | - Karen Gaudon
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
| | - Adrien Bloch
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
| | - Robin Ghanem
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
| | | | - Mridul Johari
- Tampere Neuromuscular Center, Folkhälsan Research Center, Helsinki, Finland
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Charles Van Goethem
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- Montpellier BioInformatique pour le Diagnostic Clinique (MOBIDIC), Plateau de Médecine Moléculaire et Génomique (PMMG), CHU Montpellier, Montpellier, France
| | - Michel Fardeau
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Raul Juntas Morales
- Department of Neurology, Hospital Universitario Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Casie A Genetti
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Minttu Marttila
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- HiLIFE Helsinki Institute of Life Science, Tukholmankatu 8, FI-00014, University of Helsinki, Helsinki, Finland
| | - Michel Koenig
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Alan H Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bjarne Udd
- Tampere Neuromuscular Center, Folkhälsan Research Center, Helsinki, Finland
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Mireille Cossée
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
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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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Ormrod B, Ehler E. Induced pluripotent stem cell-derived cardiomyocytes-more show than substance? Biophys Rev 2023; 15:1941-1950. [PMID: 38192353 PMCID: PMC10771368 DOI: 10.1007/s12551-023-01099-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 07/04/2023] [Indexed: 01/10/2024] Open
Abstract
Cardiomyocytes that are derived from human-induced pluripotent stem cells (iPSC-CM) are an exciting tool to investigate cardiomyopathy disease mechanisms at the cellular level as well as to screen for potential side effects of novel drugs. However, currently their benefit is limited due to their fairly immature differentiation status under conventional culture conditions. This review is mainly aimed at researchers outside of the iPSC-CM field and will describe potential pitfalls and which features at the level of the myofibrils would be desired to make them a more representative model system. We will also discuss different strategies that may help to achieve these.
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Affiliation(s)
- Beth Ormrod
- School of Cardiovascular and Metabolic Medicine and Sciences, King’s College London, London, SE1 1UL UK
| | - Elisabeth Ehler
- School of Cardiovascular and Metabolic Medicine and Sciences, King’s College London, London, SE1 1UL UK
- Randall Centre for Cell and Molecular Biophysics (School of Basic and Biosciences), Room 3.26A, New Hunt’s House, Guy’s Campus, London, SE1 1UL UK
- British Heart Foundation Centre of Research Excellence, King’s College London, London, SE1 1UL UK
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5
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Barish S, Berg K, Drozd J, Berglund-Brown I, Khizir L, Wasson LK, Seidman CE, Seidman JG, Chen S, Brueckner M. The H2Bub1-deposition complex is required for human and mouse cardiogenesis. Development 2023; 150:dev201899. [PMID: 38038666 PMCID: PMC10730087 DOI: 10.1242/dev.201899] [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: 04/28/2023] [Accepted: 10/10/2023] [Indexed: 12/02/2023]
Abstract
De novo variants affecting monoubiquitylation of histone H2B (H2Bub1) are enriched in human congenital heart disease. H2Bub1 is required in stem cell differentiation, cilia function, post-natal cardiomyocyte maturation and transcriptional elongation. However, how H2Bub1 affects cardiogenesis is unknown. We show that the H2Bub1-deposition complex (RNF20-RNF40-UBE2B) is required for mouse cardiogenesis and for differentiation of human iPSCs into cardiomyocytes. Mice with cardiac-specific Rnf20 deletion are embryonic lethal and have abnormal myocardium. We then analyzed H2Bub1 marks during differentiation of human iPSCs into cardiomyocytes. H2Bub1 is erased from most genes at the transition from cardiac mesoderm to cardiac progenitor cells but is preserved on a subset of long cardiac-specific genes. When H2Bub1 is reduced in iPSC-derived cardiomyocytes, long cardiac-specific genes have fewer full-length transcripts. This correlates with H2Bub1 accumulation near the center of these genes. H2Bub1 accumulation near the center of tissue-specific genes was also observed in embryonic fibroblasts and fetal osteoblasts. In summary, we show that normal H2Bub1 distribution is required for cardiogenesis and cardiomyocyte differentiation, and suggest that H2Bub1 regulates tissue-specific gene expression by increasing the amount of full-length transcripts.
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Affiliation(s)
- Syndi Barish
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Kathryn Berg
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Jeffrey Drozd
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Isabella Berglund-Brown
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Labeeqa Khizir
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Lauren K. Wasson
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Christine E. Seidman
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Harvard University, Boston, MA 02115, USA
| | | | - Sidi Chen
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Martina Brueckner
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
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6
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Tamborrini D, Wang Z, Wagner T, Tacke S, Stabrin M, Grange M, Kho AL, Rees M, Bennett P, Gautel M, Raunser S. Structure of the native myosin filament in the relaxed cardiac sarcomere. Nature 2023; 623:863-871. [PMID: 37914933 PMCID: PMC10665186 DOI: 10.1038/s41586-023-06690-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023]
Abstract
The thick filament is a key component of sarcomeres, the basic units of striated muscle1. Alterations in thick filament proteins are associated with familial hypertrophic cardiomyopathy and other heart and muscle diseases2. Despite the central importance of the thick filament, its molecular organization remains unclear. Here we present the molecular architecture of native cardiac sarcomeres in the relaxed state, determined by cryo-electron tomography. Our reconstruction of the thick filament reveals the three-dimensional organization of myosin, titin and myosin-binding protein C (MyBP-C). The arrangement of myosin molecules is dependent on their position along the filament, suggesting specialized capacities in terms of strain susceptibility and force generation. Three pairs of titin-α and titin-β chains run axially along the filament, intertwining with myosin tails and probably orchestrating the length-dependent activation of the sarcomere. Notably, whereas the three titin-α chains run along the entire length of the thick filament, titin-β chains do not. The structure also demonstrates that MyBP-C bridges thin and thick filaments, with its carboxy-terminal region binding to the myosin tails and directly stabilizing the OFF state of the myosin heads in an unforeseen manner. These results provide a foundation for future research investigating muscle disorders involving sarcomeric components.
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Affiliation(s)
- Davide Tamborrini
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Zhexin Wang
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Thorsten Wagner
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Sebastian Tacke
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Markus Stabrin
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Michael Grange
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
- Structural Biology, The Rosalind Franklin Institute, Didcot, UK
| | - Ay Lin Kho
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Martin Rees
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Pauline Bennett
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Mathias Gautel
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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7
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Coscarella IL, Landim-Vieira M, Rastegarpouyani H, Chase PB, Irianto J, Pinto JR. Nucleus Mechanosensing in Cardiomyocytes. Int J Mol Sci 2023; 24:13341. [PMID: 37686151 PMCID: PMC10487505 DOI: 10.3390/ijms241713341] [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: 07/14/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
Cardiac muscle contraction is distinct from the contraction of other muscle types. The heart continuously undergoes contraction-relaxation cycles throughout an animal's lifespan. It must respond to constantly varying physical and energetic burdens over the short term on a beat-to-beat basis and relies on different mechanisms over the long term. Muscle contractility is based on actin and myosin interactions that are regulated by cytoplasmic calcium ions. Genetic variants of sarcomeric proteins can lead to the pathophysiological development of cardiac dysfunction. The sarcomere is physically connected to other cytoskeletal components. Actin filaments, microtubules and desmin proteins are responsible for these interactions. Therefore, mechanical as well as biochemical signals from sarcomeric contractions are transmitted to and sensed by other parts of the cardiomyocyte, particularly the nucleus which can respond to these stimuli. Proteins anchored to the nuclear envelope display a broad response which remodels the structure of the nucleus. In this review, we examine the central aspects of mechanotransduction in the cardiomyocyte where the transmission of mechanical signals to the nucleus can result in changes in gene expression and nucleus morphology. The correlation of nucleus sensing and dysfunction of sarcomeric proteins may assist the understanding of a wide range of functional responses in the progress of cardiomyopathic diseases.
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Affiliation(s)
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Hosna Rastegarpouyani
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
- Institute for Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - Prescott Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Jerome Irianto
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
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8
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Nelson S, Beck-Previs S, Sadayappan S, Tong C, Warshaw DM. Myosin-binding protein C stabilizes, but is not the sole determinant of SRX myosin in cardiac muscle. J Gen Physiol 2023; 155:e202213276. [PMID: 36688870 PMCID: PMC9884578 DOI: 10.1085/jgp.202213276] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/08/2022] [Accepted: 01/03/2023] [Indexed: 01/24/2023] Open
Abstract
The myosin super-relaxed (SRX) state is central to striated muscle metabolic and functional regulation. In skeletal muscle, SRX myosin are predominantly colocalized with myosin-binding protein C (MyBP-C) in the sarcomere C-zone. To define how cardiac MyBP-C (cMyBP-C) and its specific domains contribute to stabilizing the SRX state in cardiac muscle, we took advantage of transgenic cMyBP-C null mice and those expressing cMyBP-C with a 271-residue N-terminal truncation. Utilizing super-resolution microscopy, we determined the lifetime and subsarcomeric location of individual fluorescent-ATP turnover events within isolated cardiac myofibrils. The proportion of SRX myosin demonstrated a gradient along the half-thick filament, highest in the P- and C-zones (72 ± 9% and 71 ± 6%, respectively) and lower in the D-zone (45 ± 10%), which lies farther from the sarcomere center and lacks cMyBP-C, suggesting a possible role for cMyBP-C in stabilizing the SRX. However, myofibrils from cMyBP-C null mice demonstrated an ∼40% SRX reduction, not only within the now cMyBP-C-free C-zone (49 ± 9% SRX), but also within the D-zone (22 ± 5% SRX). These data suggest that the influence of cMyBP-C on the SRX state is not limited to the C-zone but extends along the thick filament. Interestingly, myofibrils with N-terminal truncated cMyBP-C had an SRX content and spatial gradient similar to the cMyBP-C null, indicating that the N terminus of cMyBP-C is necessary for cMyBP-C's role in enhancing the SRX gradient along the entire thick filament. Given that SRX myosin exist as a gradient along the thick filament that is highest in the C-zone, even in the absence of cMyBP-C or its N-terminus, an inherent bias must exist in the structure of the thick filament to stabilize the SRX state.
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Affiliation(s)
- Shane Nelson
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT, USA
| | - Samantha Beck-Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT, USA
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Carl Tong
- Department of Medical Physiology, Texas A&M University, Bryan, TX, USA
| | - David M. Warshaw
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT, USA
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9
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Olie CS, Pinto-Fernández A, Damianou A, Vendrell I, Mei H, den Hamer B, van der Wal E, de Greef JC, Raz V, Kessler BM. USP18 is an essential regulator of muscle cell differentiation and maturation. Cell Death Dis 2023; 14:231. [PMID: 37002195 PMCID: PMC10066380 DOI: 10.1038/s41419-023-05725-z] [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: 10/27/2022] [Revised: 02/14/2023] [Accepted: 03/07/2023] [Indexed: 04/03/2023]
Abstract
The ubiquitin proteasomal system is a critical regulator of muscle physiology, and impaired UPS is key in many muscle pathologies. Yet, little is known about the function of deubiquitinating enzymes (DUBs) in the muscle cell context. We performed a genetic screen to identify DUBs as potential regulators of muscle cell differentiation. Surprisingly, we observed that the depletion of ubiquitin-specific protease 18 (USP18) affected the differentiation of muscle cells. USP18 depletion first stimulated differentiation initiation. Later, during differentiation, the absence of USP18 expression abrogated myotube maintenance. USP18 enzymatic function typically attenuates the immune response by removing interferon-stimulated gene 15 (ISG15) from protein substrates. However, in muscle cells, we found that USP18, predominantly nuclear, regulates differentiation independent of ISG15 and the ISG response. Exploring the pattern of RNA expression profiles and protein networks whose levels depend on USP18 expression, we found that differentiation initiation was concomitant with reduced expression of the cell-cycle gene network and altered expression of myogenic transcription (co) factors. We show that USP18 depletion altered the calcium channel gene network, resulting in reduced calcium flux in myotubes. Additionally, we show that reduced expression of sarcomeric proteins in the USP18 proteome was consistent with reduced contractile force in an engineered muscle model. Our results revealed nuclear USP18 as a critical regulator of differentiation initiation and maintenance, independent of ISG15 and its role in the ISG response.
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Affiliation(s)
- Cyriel Sebastiaan Olie
- Human Genetics department, Leiden University Medical Centre, 2333ZC, Leiden, The Netherlands
| | - Adán Pinto-Fernández
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, UK
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Andreas Damianou
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, UK
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Iolanda Vendrell
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, UK
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Centre, 2333ZC, Leiden, The Netherlands
| | - Bianca den Hamer
- Human Genetics department, Leiden University Medical Centre, 2333ZC, Leiden, The Netherlands
| | - Erik van der Wal
- Human Genetics department, Leiden University Medical Centre, 2333ZC, Leiden, The Netherlands
| | - Jessica C de Greef
- Human Genetics department, Leiden University Medical Centre, 2333ZC, Leiden, The Netherlands
| | - Vered Raz
- Human Genetics department, Leiden University Medical Centre, 2333ZC, Leiden, The Netherlands.
| | - Benedikt M Kessler
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, UK.
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK.
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10
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Broadway-Stringer S, Jiang H, Wadmore K, Hooper C, Douglas G, Steeples V, Azad AJ, Singer E, Reyat JS, Galatik F, Ehler E, Bennett P, Kalisch-Smith JI, Sparrow DB, Davies B, Djinovic-Carugo K, Gautel M, Watkins H, Gehmlich K. Insights into the Role of a Cardiomyopathy-Causing Genetic Variant in ACTN2. Cells 2023; 12:721. [PMID: 36899856 PMCID: PMC10001372 DOI: 10.3390/cells12050721] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/13/2023] [Accepted: 02/21/2023] [Indexed: 03/12/2023] Open
Abstract
Pathogenic variants in ACTN2, coding for alpha-actinin 2, are known to be rare causes of Hypertrophic Cardiomyopathy. However, little is known about the underlying disease mechanisms. Adult heterozygous mice carrying the Actn2 p.Met228Thr variant were phenotyped by echocardiography. For homozygous mice, viable E15.5 embryonic hearts were analysed by High Resolution Episcopic Microscopy and wholemount staining, complemented by unbiased proteomics, qPCR and Western blotting. Heterozygous Actn2 p.Met228Thr mice have no overt phenotype. Only mature males show molecular parameters indicative of cardiomyopathy. By contrast, the variant is embryonically lethal in the homozygous setting and E15.5 hearts show multiple morphological abnormalities. Molecular analyses, including unbiased proteomics, identified quantitative abnormalities in sarcomeric parameters, cell-cycle defects and mitochondrial dysfunction. The mutant alpha-actinin protein is found to be destabilised, associated with increased activity of the ubiquitin-proteasomal system. This missense variant in alpha-actinin renders the protein less stable. In response, the ubiquitin-proteasomal system is activated; a mechanism that has been implicated in cardiomyopathies previously. In parallel, a lack of functional alpha-actinin is thought to cause energetic defects through mitochondrial dysfunction. This seems, together with cell-cycle defects, the likely cause of the death of the embryos. The defects also have wide-ranging morphological consequences.
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Affiliation(s)
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford OX3 9DU, UK
| | - Kirsty Wadmore
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Charlotte Hooper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford OX3 9DU, UK
| | - Gillian Douglas
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford OX3 9DU, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford OX3 9DU, UK
| | - Amar J. Azad
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Evie Singer
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Jasmeet S. Reyat
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Frantisek Galatik
- Department of Physiology, Faculty of Science, Charles University, 12800 Prague, Czech Republic
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London SE1 9RT, UK
- School of Cardiovascular and Metabolic Medicine and Sciences, British Heart Foundation Centre of Research Excellence, King’s College London, London SE1 9RT, UK
| | - Pauline Bennett
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London SE1 9RT, UK
| | | | - Duncan B. Sparrow
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Benjamin Davies
- Transgenic Core, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Kristina Djinovic-Carugo
- European Molecular Biology Laboratory, 38000 Grenoble, France
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Mathias Gautel
- School of Basic and Medical Biosciences, British Heart Foundation Centre of Research Excellence, King’s College London, London SE1 9RT, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford OX3 9DU, UK
| | - Katja Gehmlich
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford OX3 9DU, UK
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11
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Dowling P, Gargan S, Swandulla D, Ohlendieck K. Fiber-Type Shifting in Sarcopenia of Old Age: Proteomic Profiling of the Contractile Apparatus of Skeletal Muscles. Int J Mol Sci 2023; 24:ijms24032415. [PMID: 36768735 PMCID: PMC9916839 DOI: 10.3390/ijms24032415] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
The progressive loss of skeletal muscle mass and concomitant reduction in contractile strength plays a central role in frailty syndrome. Age-related neuronal impairments are closely associated with sarcopenia in the elderly, which is characterized by severe muscular atrophy that can considerably lessen the overall quality of life at old age. Mass-spectrometry-based proteomic surveys of senescent human skeletal muscles, as well as animal models of sarcopenia, have decisively improved our understanding of the molecular and cellular consequences of muscular atrophy and associated fiber-type shifting during aging. This review outlines the mass spectrometric identification of proteome-wide changes in atrophying skeletal muscles, with a focus on contractile proteins as potential markers of changes in fiber-type distribution patterns. The observed trend of fast-to-slow transitions in individual human skeletal muscles during the aging process is most likely linked to a preferential susceptibility of fast-twitching muscle fibers to muscular atrophy. Studies with senescent animal models, including mostly aged rodent skeletal muscles, have confirmed fiber-type shifting. The proteomic analysis of fast versus slow isoforms of key contractile proteins, such as myosin heavy chains, myosin light chains, actins, troponins and tropomyosins, suggests them as suitable bioanalytical tools of fiber-type transitions during aging.
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Affiliation(s)
- Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
| | - Stephen Gargan
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
| | - Dieter Swandulla
- Institute of Physiology, University of Bonn, D53115 Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Correspondence: ; Tel.: +353-1-7083842
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12
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Baraldo M, Zorzato S, Dondjang AHT, Geremia A, Nogara L, Dumitras AG, Canato M, Marcucci L, Nolte H, Blaauw B. Inducible deletion of raptor and mTOR from adult skeletal muscle impairs muscle contractility and relaxation. J Physiol 2022; 600:5055-5075. [PMID: 36255030 DOI: 10.1113/jp283686] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/20/2022] [Indexed: 01/05/2023] Open
Abstract
Skeletal muscle weakness has been associated with different pathological conditions, including sarcopenia and muscular dystrophy, and is accompanied by altered mammalian target of rapamycin (mTOR) signalling. We wanted to elucidate the functional role of mTOR in muscle contractility. Most loss-of-function studies for mTOR signalling have used the drug rapamycin to inhibit some of the signalling downstream of mTOR. However, given that rapamycin does not inhibit all mTOR signalling completely, we generated a double knockout for mTOR and for the scaffold protein of mTORC1, raptor, in skeletal muscle. We found that double knockout in mice results in a more severe phenotype compared with deletion of raptor or mTOR alone. Indeed, these animals display muscle weakness, increased fibre denervation and a slower muscle relaxation following tetanic stimulation. This is accompanied by a shift towards slow-twitch fibres and changes in the expression levels of calcium-related genes, such as Serca1 and Casq1. Double knockout mice show a decrease in calcium decay kinetics after tetanus in vivo, suggestive of a reduced calcium reuptake. In addition, RNA sequencing analysis revealed that many downregulated genes, such as Tcap and Fhod3, are linked to sarcomere organization. These results suggest a key role for mTOR signalling in maintaining proper fibre relaxation in skeletal muscle. KEY POINTS: Skeletal muscle wasting and weakness have been associated with different pathological conditions, including sarcopenia and muscular dystrophy, and are accompanied by altered mammalian target of rapamycin (mTOR) signalling. Mammalian target of rapamycin plays a crucial role in the maintenance of muscle mass and functionality. We found that the loss of both mTOR and raptor results in contractile abnormalities, with severe muscle weakness and delayed relaxation following tetanic stimulation. These results are associated with alterations in the expression of genes involved in sarcomere organization and calcium handling and with an impairment in calcium reuptake after contraction. Taken together, these results provide a mechanistic insight into the role of mTOR in muscle contractility.
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Affiliation(s)
- Martina Baraldo
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Sabrina Zorzato
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Achille Homère Tchampda Dondjang
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Alessia Geremia
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Leonardo Nogara
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ana Georgia Dumitras
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marta Canato
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Center for Biosystems Dynamics Research, RIKEN, Suita, Japan
| | - Hendrik Nolte
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
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13
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Agarwal R, Wakimoto H, Paulo JA, Zhang Q, Reichart D, Toepfer C, Sharma A, Tai AC, Lun M, Gorham J, DePalma SR, Gygi SP, Seidman J, Seidman CE. Pathogenesis of Cardiomyopathy Caused by Variants in ALPK3, an Essential Pseudokinase in the Cardiomyocyte Nucleus and Sarcomere. Circulation 2022; 146:1674-1693. [PMID: 36321451 PMCID: PMC9698156 DOI: 10.1161/circulationaha.122.059688] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND ALPK3 encodes α-kinase 3, a muscle-specific protein of unknown function. ALPK3 loss-of-function variants cause cardiomyopathy with distinctive clinical manifestations in both children and adults, but the molecular functions of ALPK3 remain poorly understood. METHODS We explored the putative kinase activity of ALPK3 and the consequences of damaging variants using isogenic human induced pluripotent stem cell-derived cardiomyocytes, mice, and human patient tissues. RESULTS Multiple sequence alignment of all human α-kinase domains and their orthologs revealed 4 conserved residues that were variant only in ALPK3, demonstrating evolutionary divergence of the ALPK3 α-kinase domain sequence. Phosphoproteomic evaluation of both ALPK3 kinase domain inhibition and overexpression failed to detect significant changes in catalytic activity, establishing ALPK3 as a pseudokinase. Investigations into alternative functions revealed that ALPK3 colocalized with myomesin proteins (MYOM1, MYOM2) at both the nuclear envelope and the sarcomere M-band. ALPK3 loss-of-function variants caused myomesin proteins to mislocalize and also dysregulated several additional M-band proteins involved in sarcomere protein turnover, which ultimately impaired cardiomyocyte structure and function. CONCLUSIONS ALPK3 is an essential cardiac pseudokinase that inserts in the nuclear envelope and the sarcomere M-band. Loss of ALPK3 causes mislocalization of myomesins, critical force-buffering proteins in cardiomyocytes, and also dysregulates M-band proteins necessary for sarcomere protein turnover. We conclude that ALPK3 cardiomyopathy induces ventricular dilatation caused by insufficient myomesin-mediated force buffering and hypertrophy by impairment of sarcomere proteostasis.
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Affiliation(s)
- Radhika Agarwal
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Hiroko Wakimoto
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Joao A. Paulo
- Department of Cell Biology (J.A.P., S.P.G.), Harvard Medical School, Boston, MA
| | - Qi Zhang
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Daniel Reichart
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Christopher Toepfer
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA.,Radcliffe Department of Medicine (C.T.), University of Oxford, United Kingdom.,Wellcome Centre for Human Genetics (C.T.), University of Oxford, United Kingdom
| | - Arun Sharma
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA.,Board of Governors Regenerative Medicine Institute (A.S.), Cedars-Sinai Medical Center, Los Angeles, CA.,Smidt Heart Institute (A.S.), Cedars-Sinai Medical Center, Los Angeles, CA.,Department of Biomedical Sciences (A.S.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Angela C. Tai
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Mingyue Lun
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Joshua Gorham
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Steven R. DePalma
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Steven P. Gygi
- Department of Cell Biology (J.A.P., S.P.G.), Harvard Medical School, Boston, MA
| | - J.G. Seidman
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA
| | - Christine E. Seidman
- Department of Genetics (R.A., H.W., Q.Z., D.R., C.T., A.S., A.C.T., M.L., J.G., S.R.D., J.G.S., C.E.S.), Harvard Medical School, Boston, MA.,Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.).,Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
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14
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Ahmed RE, Tokuyama T, Anzai T, Chanthra N, Uosaki H. Sarcomere maturation: function acquisition, molecular mechanism, and interplay with other organelles. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210325. [PMID: 36189811 PMCID: PMC9527934 DOI: 10.1098/rstb.2021.0325] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
During postnatal cardiac development, cardiomyocytes mature and turn into adult ones. Hence, all cellular properties, including morphology, structure, physiology and metabolism, are changed. One of the most important aspects is the contractile apparatus, of which the minimum unit is known as a sarcomere. Sarcomere maturation is evident by enhanced sarcomere alignment, ultrastructural organization and myofibrillar isoform switching. Any maturation process failure may result in cardiomyopathy. Sarcomere function is intricately related to other organelles, and the growing evidence suggests reciprocal regulation of sarcomere and mitochondria on their maturation. Herein, we summarize the molecular mechanism that regulates sarcomere maturation and the interplay between sarcomere and other organelles in cardiomyocyte maturation. This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.
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Affiliation(s)
- Razan E Ahmed
- Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Takeshi Tokuyama
- Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Tatsuya Anzai
- Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.,Department of Pediatrics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Nawin Chanthra
- Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Hideki Uosaki
- Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
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15
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Schöck F, González-Morales N. The insect perspective on Z-disc structure and biology. J Cell Sci 2022; 135:277280. [PMID: 36226637 DOI: 10.1242/jcs.260179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myofibrils are the intracellular structures formed by actin and myosin filaments. They are paracrystalline contractile cables with unusually well-defined dimensions. The sliding of actin past myosin filaments powers contractions, and the entire system is held in place by a structure called the Z-disc, which anchors the actin filaments. Myosin filaments, in turn, are anchored to another structure called the M-line. Most of the complex architecture of myofibrils can be reduced to studying the Z-disc, and recently, important advances regarding the arrangement and function of Z-discs in insects have been published. On a very small scale, we have detailed protein structure information. At the medium scale, we have cryo-electron microscopy maps, super-resolution microscopy and protein-protein interaction networks, while at the functional scale, phenotypic data are available from precise genetic manipulations. All these data aim to answer how the Z-disc works and how it is assembled. Here, we summarize recent data from insects and explore how it fits into our view of the Z-disc, myofibrils and, ultimately, muscles.
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Affiliation(s)
- Frieder Schöck
- Department of Biology, McGill University, Montreal, Quebec, H3A 1B1, Canada
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16
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Koser F, Hobbach AJ, Abdellatif M, Herbst V, Türk C, Reinecke H, Krüger M, Sedej S, Linke WA. Acetylation and phosphorylation changes to cardiac proteins in experimental HFpEF due to metabolic risk reveal targets for treatment. Life Sci 2022; 309:120998. [PMID: 36179815 DOI: 10.1016/j.lfs.2022.120998] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/24/2022] [Accepted: 09/21/2022] [Indexed: 11/17/2022]
Abstract
AIMS Despite the high prevalence of heart failure with preserved ejection fraction (HFpEF), the pathomechanisms remain elusive and specific therapy is lacking. Disease-causing factors include metabolic risk, notably obesity. However, proteomic changes in HFpEF are poorly understood, hampering therapeutic strategies. We sought to elucidate how metabolic syndrome affects cardiac protein expression, phosphorylation and acetylation in the Zucker diabetic fatty/Spontaneously hypertensive heart failure F1 (ZSF1) rat HFpEF model, and to evaluate changes regarding their potential for treatment. MAIN METHODS ZSF1 obese and lean rats were fed a Purina diet up to the onset of HFpEF in the obese animals. We quantified the proteome, phosphoproteome and acetylome of ZSF1 obese versus lean heart tissues by mass spectrometry and singled out targets for site-specific evaluation. KEY FINDINGS The acetylome of ZSF1 obese versus lean hearts was more severely altered (21 % of proteins changed) than the phosphoproteome (9 %) or proteome (3 %). Proteomic alterations, confirmed by immunoblotting, indicated low-grade systemic inflammation and endothelial remodeling in obese hearts, but low nitric oxide-dependent oxidative/nitrosative stress. Altered acetylation in ZSF1 obese hearts mainly affected pathways important for metabolism, energy production and mechanical function, including hypo-acetylation of mechanical proteins but hyper-acetylation of proteins regulating fatty acid metabolism. Hypo-acetylation and hypo-phosphorylation of elastic titin in ZSF1 obese hearts could explain myocardial stiffening. SIGNIFICANCE Cardiometabolic syndrome alters posttranslational modifications, notably acetylation, in experimental HFpEF. Pathway changes implicate a HFpEF signature of low-grade inflammation, endothelial dysfunction, metabolic and mechanical impairment, and suggest titin stiffness and mitochondrial metabolism as promising therapeutic targets.
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Affiliation(s)
- Franziska Koser
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Anastasia J Hobbach
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, University Hospital Münster, Münster, Germany
| | | | - Viktoria Herbst
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Clara Türk
- 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
| | - Holger Reinecke
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, University Hospital Münster, Münster, 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
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria; Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, Münster, Germany.
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17
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Wang J, Wang C, Xie H, Feng X, Wei L, Wang B, Li T, Pi M, Gong L. Case Report: Tetralogy of Fallot in a Chinese Family Caused by a Novel Missense Variant of MYOM2. Front Cardiovasc Med 2022; 9:863650. [PMID: 35872890 PMCID: PMC9300848 DOI: 10.3389/fcvm.2022.863650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
Background Rare genetic variants have been identified to be important contributors to the risk of Tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease (CHD). But relatively limited familial studies with small numbers of TOF cases have been reported to date. In this study, we aimed to identify novel pathogenic genes and variants that caused TOF in a Chinese family using whole exome sequencing (WES). Methods A Chinese family whose twins were affected by TOF were recruited for this study. A WES was performed for the affected twins, their healthy brother, and parents to identify the potential pathogenic mutated gene(s). Heterozygous variants carried by the twins, but not the unaffected brother, were retained. Public databases were used to assess the frequencies of the selected variants, and online prediction tools were accessed to predict the influences of these variants on protein function. The final candidate variant was further confirmed by Sanger sequencing in other members of the family. Results After several filtering processes, a heterozygous missense variant in the MYOM2 gene (NM_003970.4:c.3097C>T:p.R1033C) was identified and confirmed by Sanger sequencing in the affected twins and their unaffected father, suggesting an inheritance pattern with incomplete penetrance. The variant was found to be extremely rare in the public databases. Furthermore, the mutated site was highly conserved among mammals, and as shown using multiple online prediction tools, this variant was predicted to be a detrimental variant. Conclusion We assessed a family with TOF caused by a rare heterozygous missense variant of MYOM2. Our findings not only further confirm the significant role of genetics in the incidence of TOF but also expand the spectrum of the gene variants that lead to TOF.
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Affiliation(s)
- Jing Wang
- Department of Medical Genetics and Developmental Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Chunyan Wang
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Center for Genetics, National Research Institute for Family Planning, Beijing, China
| | - Haiyang Xie
- Department of Cardiothoracic Surgery, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyuan Feng
- Department of Echocardiography, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Wei
- Department of Cardiothoracic Surgery, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Binbin Wang
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Center for Genetics, National Research Institute for Family Planning, Beijing, China
| | - Tengyan Li
- Center for Genetics, National Research Institute for Family Planning, Beijing, China
| | - Mingan Pi
- Department of Cardiothoracic Surgery, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Mingan Pi
| | - Li Gong
- Department of Cardiothoracic Surgery, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Li Gong
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18
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Schwaerzer GK, Casteel DE, Cividini F, Kalyanaraman H, Zhuang S, Gu Y, Peterson KL, Dillmann W, Boss GR, Pilz RB, Pilz RB. Constitutive protein kinase G activation exacerbates stress-induced cardiomyopathy. Br J Pharmacol 2022; 179:2413-2429. [PMID: 34000062 PMCID: PMC9926932 DOI: 10.1111/bph.15530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Heart failure is associated with high morbidity and mortality, and new therapeutic targets are needed. Preclinical data suggest that pharmacological activation of protein kinase G (PKG) can reduce maladaptive ventricular remodelling and cardiac dysfunction in the stressed heart. However, clinical trial results have been mixed and the effects of long-term PKG activation in the heart are unknown. EXPERIMENTAL APPROACH We characterized the cardiac phenotype of mice carrying a heterozygous knock-in mutation of PKG1 (Prkg1R177Q/+ ), which causes constitutive, cGMP-independent activation of the kinase. We examined isolated cardiac myocytes and intact mice, the latter after stress induced by surgical transaortic constriction or angiotensin II (Ang II) infusion. KEY RESULTS Cardiac myocytes from Prkg1R177Q/+ mice showed altered phosphorylation of sarcomeric proteins and reduced contractility in response to electrical stimulation, compared to cells from wild type mice. Under basal conditions, young PKG1R177Q/+ mice exhibited no obvious cardiac abnormalities, but aging animals developed mild increases in cardiac fibrosis. In response to angiotensin II infusion or fixed pressure overload induced by transaortic constriction, young PKGR177Q/+ mice exhibited excessive hypertrophic remodelling with increased fibrosis and myocyte apoptosis, leading to increased left ventricular dilation and dysfunction compared to wild type litter mates. CONCLUSION AND IMPLICATIONS Long-term PKG1 activation in mice may be harmful to the heart, especially in the presence of pressure overload and neurohumoral stress. LINKED ARTICLES This article is part of a themed issue on cGMP Signalling in Cell Growth and Survival. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.11/issuetoc.
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Affiliation(s)
- Gerburg K. Schwaerzer
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Darren E. Casteel
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Federico Cividini
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Hema Kalyanaraman
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Shunhui Zhuang
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Kirk L. Peterson
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Wolfgang Dillmann
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Gerry R. Boss
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Renate B. Pilz
- Department of Medicine, University of California San Diego, La Jolla, California 92093,Correspondence should be addressed to R.B.P. ()
| | - Renate B Pilz
- Department of Medicine, University of California San Diego, La Jolla, California, 92093, USA
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19
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Wang J, Fan Y, Wang C, Dube S, Poiesz BJ, Dube DK, Ma Z, Sanger JM, Sanger JW. Inhibitors of the Ubiquitin Proteasome System block myofibril assembly in cardiomyocytes derived from chick embryos and human pluripotent stem cells. Cytoskeleton (Hoboken) 2022; 78:461-491. [PMID: 35502133 DOI: 10.1002/cm.21697] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 11/06/2022]
Abstract
Details of sarcomeric protein assembly during de novo myofibril formation closely resemble myofibrillogenesis in skeletal and cardiac myocytes in birds, rodents and zebrafish. The arrangement of proteins during myofibrillogenesis follows a three-step process: beginning with premyofibrils, followed by nascent myofibrils, and concluding with mature myofibrils (reviewed in Sanger et al., 2017). Our aim is to determine if the same pathway is followed in human cardiomyocytes derived from human inducible pluripotent stem cells. We found that the human cardiomyocytes developed patterns of protein organization identical to the three-step series seen in the model organisms cited above. Further experiments showed that myofibril assembly can be blocked at the nascent myofibril by five different inhibitors of the Ubiquitin Proteasome System (UPS) stage in both avian and human cardiomyocytes. With the exception of Carfilzomib, removal of the UPS inhibitors allows nascent myofibrils to proceed to mature myofibrils. Some proteasomal inhibitors, such as Bortezomib and Carfilzomib, used to treat multiple myeloma patients, have off-target effects of damage to hearts in three to six percent of these patients. These cardiovascular adverse events may result from prevention of mature myofibril formation in the cardiomyocytes. In summary, our results support a common three-step model for the formation of myofibrils ranging from avian to human cardiomyocytes. The Ubiquitin Proteasome System is required for progression from nascent myofibrils to mature myofibrils. Our experiments suggest a possible explanation for the cardiac and skeletal muscle off-target effects reported in multiple myeloma patients treated with proteasome inhibitors. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | - Chenyan Wang
- Department of Biomedical & Chemical Engineering, The BioInspired Institute for Materials and Living Systems, Syracuse University, Syracuse, NY
| | - Syamalima Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Bernard J Poiesz
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Dipak K Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Zhen Ma
- Department of Biomedical & Chemical Engineering, The BioInspired Institute for Materials and Living Systems, Syracuse University, Syracuse, NY
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | - Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
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20
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Koubassova NA, Tsaturyan AK, Bershitsky SY, Ferenczi MA, Padrón R, Craig R. Interacting-heads motif explains the X-ray diffraction pattern of relaxed vertebrate skeletal muscle. Biophys J 2022; 121:1354-1366. [PMID: 35318005 PMCID: PMC9072692 DOI: 10.1016/j.bpj.2022.03.023] [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: 01/10/2022] [Revised: 01/25/2022] [Accepted: 03/17/2022] [Indexed: 11/19/2022] Open
Abstract
Electron microscopy (EM) shows that myosin heads in thick filaments isolated from striated muscles interact with each other and with the myosin tail under relaxing conditions. This "interacting-heads motif" (IHM) is highly conserved across the animal kingdom and is thought to be the basis of the super-relaxed state. However, a recent X-ray modeling study concludes, contrary to expectation, that the IHM is not present in relaxed intact muscle. We propose that this conclusion results from modeling with a thick filament 3D reconstruction in which the myosin heads have radially collapsed onto the thick filament backbone, not from absence of the IHM. Such radial collapse, by about 3-4 nm, is well established in EM studies of negatively stained myosin filaments, on which the reconstruction was based. We have tested this idea by carrying out similar X-ray modeling and determining the effect of the radial position of the heads on the goodness of fit to the X-ray pattern. We find that, when the IHM is modeled into a thick filament at a radius 3-4 nm greater than that modeled in the recent study, there is good agreement with the X-ray pattern. When the original (collapsed) radial position is used, the fit is poor, in agreement with that study. We show that modeling of the low-angle region of the X-ray pattern is relatively insensitive to the conformation of the myosin heads but very sensitive to their radial distance from the filament axis. We conclude that the IHM is sufficient to explain the X-ray diffraction pattern of intact muscle when placed at the appropriate radius.
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Affiliation(s)
| | | | - Sergey Y Bershitsky
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia
| | - Michael A Ferenczi
- Brunel Medical School, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Raúl Padrón
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts
| | - Roger Craig
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts.
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21
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Lamber EP, Guicheney P, Pinotsis N. The role of the M-band myomesin proteins in muscle integrity and cardiac disease. J Biomed Sci 2022; 29:18. [PMID: 35255917 PMCID: PMC8900313 DOI: 10.1186/s12929-022-00801-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/28/2022] [Indexed: 11/30/2022] Open
Abstract
Transversal structural elements in cross-striated muscles, such as the M-band or the Z-disc, anchor and mechanically stabilize the contractile apparatus and its minimal unit—the sarcomere. The ability of proteins to target and interact with these structural sarcomeric elements is an inevitable necessity for the correct assembly and functionality of the myofibrillar apparatus. Specifically, the M-band is a well-recognized mechanical and signaling hub dealing with active forces during contraction, while impairment of its function leads to disease and death. Research on the M-band architecture is focusing on the assembly and interactions of the three major filamentous proteins in the region, mainly the three myomesin proteins including their embryonic heart (EH) isoform, titin and obscurin. These proteins form the basic filamentous network of the M-band, interacting with each other as also with additional proteins in the region that are involved in signaling, energetic or mechanosensitive processes. While myomesin-1, titin and obscurin are found in every muscle, the expression levels of myomesin-2 (also known as M-protein) and myomesin-3 are tissue specific: myomesin-2 is mainly expressed in the cardiac and fast skeletal muscles, while myomesin-3 is mainly expressed in intermediate muscles and specific regions of the cardiac muscle. Furthermore, EH-myomesin apart from its role during embryonic stages, is present in adults with specific cardiac diseases. The current work in structural, molecular, and cellular biology as well as in animal models, provides important details about the assembly of myomesin-1, obscurin and titin, the information however about the myomesin-2 and -3, such as their interactions, localization and structural details remain very limited. Remarkably, an increasing number of reports is linking all three myomesin proteins and particularly myomesin-2 to serious cardiovascular diseases suggesting that this protein family could be more important than originally thought. In this review we will focus on the myomesin protein family, the myomesin interactions and structural differences between isoforms and we will provide the most recent evidence why the structurally and biophysically unexplored myomesin-2 and myomesin-3 are emerging as hot targets for understanding muscle function and disease.
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22
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El Kadiri Y, Ratbi I, Sefiani A, Lyahyai J. Clinical and molecular genetic analysis of early-onset myopathy with fatal cardiomyopathy: Novel biallelic M-line TTN mutation and review of the literature. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Suay-Corredera C, Alegre-Cebollada J. The mechanics of the heart: zooming in on hypertrophic cardiomyopathy and cMyBP-C. FEBS Lett 2022; 596:703-746. [PMID: 35224729 DOI: 10.1002/1873-3468.14301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/10/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), a disease characterized by cardiac muscle hypertrophy and hypercontractility, is the most frequently inherited disorder of the heart. HCM is mainly caused by variants in genes encoding proteins of the sarcomere, the basic contractile unit of cardiomyocytes. The most frequently mutated among them is MYBPC3, which encodes cardiac myosin-binding protein C (cMyBP-C), a key regulator of sarcomere contraction. In this review, we summarize clinical and genetic aspects of HCM and provide updated information on the function of the healthy and HCM sarcomere, as well as on emerging therapeutic options targeting sarcomere mechanical activity. Building on what is known about cMyBP-C activity, we examine different pathogenicity drivers by which MYBPC3 variants can cause disease, focussing on protein haploinsufficiency as a common pathomechanism also in nontruncating variants. Finally, we discuss recent evidence correlating altered cMyBP-C mechanical properties with HCM development.
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24
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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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25
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Pierantozzi E, Szentesi P, Paolini C, Dienes B, Fodor J, Oláh T, Colombini B, Rassier DE, Rubino EM, Lange S, Rossi D, Csernoch L, Bagni MA, Reggiani C, Sorrentino V. Impaired Intracellular Ca 2+ Dynamics, M-Band and Sarcomere Fragility in Skeletal Muscles of Obscurin KO Mice. Int J Mol Sci 2022; 23:1319. [PMID: 35163243 PMCID: PMC8835721 DOI: 10.3390/ijms23031319] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/16/2022] Open
Abstract
Obscurin is a giant sarcomeric protein expressed in striated muscles known to establish several interactions with other proteins of the sarcomere, but also with proteins of the sarcoplasmic reticulum and costameres. Here, we report experiments aiming to better understand the contribution of obscurin to skeletal muscle fibers, starting with a detailed characterization of the diaphragm muscle function, which we previously reported to be the most affected muscle in obscurin (Obscn) KO mice. Twitch and tetanus tension were not significantly different in the diaphragm of WT and Obscn KO mice, while the time to peak (TTP) and half relaxation time (HRT) were prolonged. Differences in force-frequency and force-velocity relationships and an enhanced fatigability are observed in an Obscn KO diaphragm with respect to WT controls. Voltage clamp experiments show that a sarcoplasmic reticulum's Ca2+ release and SERCA reuptake rates were decreased in muscle fibers from Obscn KO mice, suggesting that an impairment in intracellular Ca2+ dynamics could explain the observed differences in the TTP and HRT in the diaphragm. In partial contrast with previous observations, Obscn KO mice show a normal exercise tolerance, but fiber damage, the altered sarcomere ultrastructure and M-band disarray are still observed after intense exercise.
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Affiliation(s)
- Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy; (E.P.); (E.M.R.); (D.R.)
| | - Péter Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (P.S.); (B.D.); (J.F.); (T.O.); (L.C.)
| | - Cecilia Paolini
- Department of Neuroscience, Imaging and Clinical Sciences, University Gabriele d’ Annunzio of Chieti, 66100 Chieti, Italy;
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (P.S.); (B.D.); (J.F.); (T.O.); (L.C.)
| | - János Fodor
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (P.S.); (B.D.); (J.F.); (T.O.); (L.C.)
| | - Tamás Oláh
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (P.S.); (B.D.); (J.F.); (T.O.); (L.C.)
| | - Barbara Colombini
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (B.C.); (M.A.B.)
| | - Dilson E. Rassier
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC H2W 1S4, Canada;
| | - Egidio Maria Rubino
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy; (E.P.); (E.M.R.); (D.R.)
| | - Stephan Lange
- Biomedical Research Facility 2, School of Medicine, University of California, La Jolla, CA 92093, USA;
- Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, 413 45 Gothenburg, Sweden
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy; (E.P.); (E.M.R.); (D.R.)
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (P.S.); (B.D.); (J.F.); (T.O.); (L.C.)
| | - Maria Angela Bagni
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (B.C.); (M.A.B.)
| | - Carlo Reggiani
- Department of Biomedical Science, University of Padova, 35121 Padova, Italy;
- Science and Research Center Koper, Institute for Kinesiology Research, 6000 Koper, Slovenia
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy; (E.P.); (E.M.R.); (D.R.)
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26
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Nanosurgical Manipulation of Titin and Its M-Complex. NANOMATERIALS 2022; 12:nano12020178. [PMID: 35055197 PMCID: PMC8779236 DOI: 10.3390/nano12020178] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 01/21/2023]
Abstract
Titin is a multifunctional filamentous protein anchored in the M-band, a hexagonally organized supramolecular lattice in the middle of the muscle sarcomere. Functionally, the M-band is a framework that cross-links myosin thick filaments, organizes associated proteins, and maintains sarcomeric symmetry via its structural and putative mechanical properties. Part of the M-band appears at the C-terminal end of isolated titin molecules in the form of a globular head, named here the “M-complex”, which also serves as the point of head-to-head attachment of titin. We used high-resolution atomic force microscopy and nanosurgical manipulation to investigate the topographical and internal structure and local mechanical properties of the M-complex and its associated titin molecules. We find that the M-complex is a stable structure that corresponds to the transverse unit of the M-band organized around the myosin thick filament. M-complexes may be interlinked into an M-complex array that reflects the local structural and mechanical status of the transversal M-band lattice. Local segments of titin and the M-complex could be nanosurgically manipulated to achieve extension and domain unfolding. Long threads could be pulled out of the M-complex, suggesting that it is a compact supramolecular reservoir of extensible filaments. Nanosurgery evoked an unexpected volume increment in the M-complex, which may be related to its function as a mechanical spacer. The M-complex thus displays both elastic and plastic properties which support the idea that the M-band may be involved in mechanical functions within the muscle sarcomere.
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27
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Biophysical Reviews "Meet the Editor Series"-Elisabeth Ehler. Biophys Rev 2021; 13:579-581. [PMID: 34777613 DOI: 10.1007/s12551-021-00830-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/14/2021] [Indexed: 10/20/2022] Open
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28
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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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29
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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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30
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Abstract
Hypoxia inhibits the tricarboxylic acid (TCA) cycle and leaves glycolysis as the primary metabolic pathway responsible for converting glucose into usable energy. However, the mechanisms that compensate for this loss in energy production due to TCA cycle inactivation remain poorly understood. Glycolysis enzymes are typically diffuse and soluble in the cytoplasm under normoxic conditions. In contrast, recent studies have revealed dynamic compartmentalization of glycolysis enzymes in response to hypoxic stress in yeast, C. elegans and mammalian cells. These messenger ribonucleoprotein (mRNP) structures, termed glycolytic (G) bodies in yeast, lack membrane enclosure and display properties of phase-separated biomolecular condensates. Disruption of condensate formation correlates with defects such as impaired synaptic function in C. elegans neurons and decreased glucose flux in yeast. Concentrating glycolysis enzymes into condensates may lead to their functioning as 'metabolons' that enhance rates of glucose utilization for increased energy production. Besides condensates, glycolysis enzymes functionally associate in other organisms and specific tissues through protein-protein interactions and membrane association. However, as discussed in this Review, the functional consequences of coalescing glycolytic machinery are only just beginning to be revealed. Through ongoing studies, we anticipate the physiological importance of metabolic regulation mediated by the compartmentalization of glycolysis enzymes will continue to emerge.
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Affiliation(s)
- Gregory G Fuller
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - John K Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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31
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Crocini C, Gotthardt M. Cardiac sarcomere mechanics in health and disease. Biophys Rev 2021; 13:637-652. [PMID: 34745372 PMCID: PMC8553709 DOI: 10.1007/s12551-021-00840-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/27/2021] [Indexed: 12/23/2022] Open
Abstract
The sarcomere is the fundamental structural and functional unit of striated muscle and is directly responsible for most of its mechanical properties. The sarcomere generates active or contractile forces and determines the passive or elastic properties of striated muscle. In the heart, mutations in sarcomeric proteins are responsible for the majority of genetically inherited cardiomyopathies. Here, we review the major determinants of cardiac sarcomere mechanics including the key structural components that contribute to active and passive tension. We dissect the molecular and structural basis of active force generation, including sarcomere composition, structure, activation, and relaxation. We then explore the giant sarcomere-resident protein titin, the major contributor to cardiac passive tension. We discuss sarcomere dynamics exemplified by the regulation of titin-based stiffness and the titin life cycle. Finally, we provide an overview of therapeutic strategies that target the sarcomere to improve cardiac contraction and filling.
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Affiliation(s)
- Claudia Crocini
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- BioFrontiers Institute & Department of Molecular and Cellular Development, University of Colorado Boulder, Boulder, USA
| | - Michael Gotthardt
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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32
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Biquand A, Spinozzi S, Tonino P, Cosette J, Strom J, Elbeck Z, Knöll R, Granzier H, Lostal W, Richard I. Titin M-line insertion sequence 7 is required for proper cardiac function in mice. J Cell Sci 2021; 134:271843. [PMID: 34401916 DOI: 10.1242/jcs.258684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/06/2021] [Indexed: 11/20/2022] Open
Abstract
Titin is a giant sarcomeric protein that is involved in a large number of functions, with a primary role in skeletal and cardiac sarcomere organization and stiffness. The titin gene (TTN) is subject to various alternative splicing events, but in the region that is present at the M-line, the only exon that can be spliced out is Mex5, which encodes for the insertion sequence 7 (is7). Interestingly, in the heart, the majority of titin isoforms are Mex5+, suggesting a cardiac role for is7. Here, we performed comprehensive functional, histological, transcriptomic, microscopic and molecular analyses of a mouse model lacking the Ttn Mex5 exon (ΔMex5), and revealed that the absence of the is7 is causative for dilated cardiomyopathy. ΔMex5 mice showed altered cardiac function accompanied by increased fibrosis and ultrastructural alterations. Abnormal expression of excitation-contraction coupling proteins was also observed. The results reported here confirm the importance of the C-terminal region of titin in cardiac function and are the first to suggest a possible relationship between the is7 and excitation-contraction coupling. Finally, these findings give important insights for the identification of new targets in the treatment of titinopathies.
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Affiliation(s)
- Ariane Biquand
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Simone Spinozzi
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Paola Tonino
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | | | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - Zaher Elbeck
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institutet, 141 57 Huddinge, Sweden
| | - Ralph Knöll
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institutet, 141 57 Huddinge, Sweden.,Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, 431 50 Gothenburg, Sweden
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - William Lostal
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Isabelle Richard
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
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33
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Squire JM, Knupp C. The muscle M3 x-ray diffraction peak and sarcomere length: No evidence for disordered myosin heads out of actin overlap. J Gen Physiol 2021; 153:212534. [PMID: 34347004 PMCID: PMC8348229 DOI: 10.1085/jgp.202012859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
X-ray diffraction studies of muscle have provided a wealth of information on muscle structure and physiology, and the meridian of the diffraction pattern is particularly informative. Reconditi et al. (2014. J. Physiol.https://doi.org/10.1113/jphysiol.2013.267849) performed superb experiments on changes to the M3 meridional peak as a function of sarcomere length (SL). They found that the M3 intensity dropped almost linearly as sarcomere length increased at least to about SL = 3.0 µm, and that it followed the same track as tension, pointing toward zero at the end of overlap at ∼3.6 µm. They concluded that, just as tension could only be generated by overlapped myosin heads, so ordered myosin heads contributing to the M3 intensity could only occur in the overlap region of the A-band, and that nonoverlapped heads must be highly disordered. Here we show that this conclusion is not consistent with x-ray diffraction theory; it would not explain their observations. We discuss one possible reason for the change in M3 intensity with increasing sarcomere length in terms of increasing axial misalignment of the myosin filaments that at longer sarcomere lengths is limited by the elastic stretching of the M-band and titin.
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Affiliation(s)
- John M Squire
- Muscle Contraction Group, School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK.,Faculty of Medicine, Imperial College London, London, UK
| | - Carlo Knupp
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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34
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Wang Z, Grange M, Wagner T, Kho AL, Gautel M, Raunser S. The molecular basis for sarcomere organization in vertebrate skeletal muscle. Cell 2021; 184:2135-2150.e13. [PMID: 33765442 PMCID: PMC8054911 DOI: 10.1016/j.cell.2021.02.047] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/27/2021] [Accepted: 02/22/2021] [Indexed: 12/20/2022]
Abstract
Sarcomeres are force-generating and load-bearing devices of muscles. A precise molecular picture of how sarcomeres are built underpins understanding their role in health and disease. Here, we determine the molecular architecture of native vertebrate skeletal sarcomeres by electron cryo-tomography. Our reconstruction reveals molecular details of the three-dimensional organization and interaction of actin and myosin in the A-band, I-band, and Z-disc and demonstrates that α-actinin cross-links antiparallel actin filaments by forming doublets with 6-nm spacing. Structures of myosin, tropomyosin, and actin at ~10 Å further reveal two conformations of the "double-head" myosin, where the flexible orientation of the lever arm and light chains enable myosin not only to interact with the same actin filament, but also to split between two actin filaments. Our results provide unexpected insights into the fundamental organization of vertebrate skeletal muscle and serve as a strong foundation for future investigations of muscle diseases.
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Affiliation(s)
- Zhexin Wang
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Michael Grange
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Thorsten Wagner
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Ay Lin Kho
- The Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Excellence Centre, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Mathias Gautel
- The Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Excellence Centre, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
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35
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Solís C, Solaro RJ. Novel insights into sarcomere regulatory systems control of cardiac thin filament activation. J Gen Physiol 2021; 153:211903. [PMID: 33740037 PMCID: PMC7988513 DOI: 10.1085/jgp.202012777] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/23/2021] [Indexed: 12/11/2022] Open
Abstract
Our review focuses on sarcomere regulatory mechanisms with a discussion of cardiac-specific modifications to the three-state model of thin filament activation from a blocked to closed to open state. We discuss modulation of these thin filament transitions by Ca2+, by crossbridge interactions, and by thick filament–associated proteins, cardiac myosin–binding protein C (cMyBP-C), cardiac regulatory light chain (cRLC), and titin. Emerging evidence supports the idea that the cooperative activation of the thin filaments despite a single Ca2+ triggering regulatory site on troponin C (cTnC) cannot be considered in isolation of other functional domains of the sarcomere. We discuss long- and short-range interactions among these domains with the regulatory units of thin filaments, including proteins at the barbed end at the Z-disc and the pointed end near the M-band. Important to these discussions is the ever-increasing understanding of the role of cMyBP-C, cRLC, and titin filaments. Detailed knowledge of these control processes is critical to the understanding of mechanisms sustaining physiological cardiac state with varying hemodynamic load, to better defining genetic and acquired cardiac disorders, and to developing targets for therapies at the level of the sarcomeres.
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Affiliation(s)
- Christopher Solís
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
| | - R John Solaro
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
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36
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The Role of Z-disc Proteins in Myopathy and Cardiomyopathy. Int J Mol Sci 2021; 22:ijms22063058. [PMID: 33802723 PMCID: PMC8002584 DOI: 10.3390/ijms22063058] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/07/2021] [Accepted: 03/11/2021] [Indexed: 12/11/2022] Open
Abstract
The Z-disc acts as a protein-rich structure to tether thin filament in the contractile units, the sarcomeres, of striated muscle cells. Proteins found in the Z-disc are integral for maintaining the architecture of the sarcomere. They also enable it to function as a (bio-mechanical) signalling hub. Numerous proteins interact in the Z-disc to facilitate force transduction and intracellular signalling in both cardiac and skeletal muscle. This review will focus on six key Z-disc proteins: α-actinin 2, filamin C, myopalladin, myotilin, telethonin and Z-disc alternatively spliced PDZ-motif (ZASP), which have all been linked to myopathies and cardiomyopathies. We will summarise pathogenic variants identified in the six genes coding for these proteins and look at their involvement in myopathy and cardiomyopathy. Listing the Minor Allele Frequency (MAF) of these variants in the Genome Aggregation Database (GnomAD) version 3.1 will help to critically re-evaluate pathogenicity based on variant frequency in normal population cohorts.
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37
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Muscle Proteomic Profile before and after Enzyme Replacement Therapy in Late-Onset Pompe Disease. Int J Mol Sci 2021; 22:ijms22062850. [PMID: 33799647 PMCID: PMC8001152 DOI: 10.3390/ijms22062850] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/07/2021] [Accepted: 03/08/2021] [Indexed: 12/29/2022] Open
Abstract
Mutations in the acidic alpha-glucosidase (GAA) coding gene cause Pompe disease. Late-onset Pompe disease (LOPD) is characterized by progressive proximal and axial muscle weakness and atrophy, causing respiratory failure. Enzyme replacement therapy (ERT), based on recombinant human GAA infusions, is the only available treatment; however, the efficacy of ERT is variable. Here we address the question whether proteins at variance in LOPD muscle of patients before and after 1 year of ERT, compared withhealthy age-matched subjects (CTR), reveal a specific signature. Proteins extracted from skeletal muscle of LOPD patients and CTR were analyzed by combining gel based (two-dimensional difference gel electrophoresis) and label-free (liquid chromatography-mass spectrometry) proteomic approaches, and ingenuity pathway analysis. Upstream regulators targeting autophagy and lysosomal tethering were assessed by immunoblotting. 178 proteins were changed in abundance in LOPD patients, 47 of them recovered normal level after ERT. Defects in oxidative metabolism, muscle contractile protein regulation, cytoskeletal rearrangement, and membrane reorganization persisted. Metabolic changes, ER stress and UPR (unfolded protein response) contribute to muscle proteostasis dysregulation with active membrane remodeling (high levels of LC3BII/LC3BI) and accumulation of p62, suggesting imbalance in the autophagic process. Active lysosome biogenesis characterizes both LOPD PRE and POST, unparalleled by molecules involved in lysosome tethering (VAMP8, SNAP29, STX17, and GORASP2) and BNIP3. In conclusion this study reveals a specific signature that suggests ERT prolongation and molecular targets to ameliorate patient’s outcome.
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38
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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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39
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Hang C, Song Y, Li Y, Zhang S, Chang Y, Bai R, Saleem A, Jiang M, Lu W, Lan F, Cui M. Knockout of MYOM1 in human cardiomyocytes leads to myocardial atrophy via impairing calcium homeostasis. J Cell Mol Med 2021; 25:1661-1676. [PMID: 33452765 PMCID: PMC7875908 DOI: 10.1111/jcmm.16268] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 12/27/2022] Open
Abstract
Myomesin-1 (encoded by MYOM1 gene) is expressed in almost all cross-striated muscles, whose family (together with myomesin-2 and myomesin-3) helps to cross-link adjacent myosin to form the M-line in myofibrils. However, little is known about its biological function, causal relationship and mechanisms underlying the MYOM1-related myopathies (especially in the heart). Regrettably, there is no MYMO1 knockout model for its study so far. A better and further understanding of MYOM1 biology is urgently needed. Here, we used CRISPR/Cas9 gene-editing technology to establish an MYOM1 knockout human embryonic stem cell line (MYOM1-/- hESC), which was then differentiated into myomesin-1 deficient cardiomyocytes (MYOM1-/- hESC-CMs) in vitro. We found that myomesin-1 plays an important role in sarcomere assembly, contractility regulation and cardiomyocytes development. Moreover, myomesin-1-deficient hESC-CMs can recapitulate myocardial atrophy phenotype in vitro. Based on this model, not only the biological function of MYOM1, but also the aetiology, pathogenesis, and potential treatments of myocardial atrophy caused by myomesin-1 deficiency can be studied.
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Affiliation(s)
- Chengwen Hang
- Department of CardiologyPeking University Third HospitalBeijingChina
| | - Yuanxiu Song
- Department of CardiologyPeking University Third HospitalBeijingChina
| | - Ya’nan Li
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Siyao Zhang
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Yun Chang
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Rui Bai
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Amina Saleem
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Mengqi Jiang
- Department of CardiologyPeking University Third HospitalBeijingChina
| | - Wenjing Lu
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Feng Lan
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Ming Cui
- Department of CardiologyPeking University Third HospitalBeijingChina
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40
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Gagaoua M, Troy D, Mullen AM. The Extent and Rate of the Appearance of the Major 110 and 30 kDa Proteolytic Fragments during Post-Mortem Aging of Beef Depend on the Glycolysing Rate of the Muscle and Aging Time: An LC-MS/MS Approach to Decipher Their Proteome and Associated Pathways. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:602-614. [PMID: 33377770 DOI: 10.1021/acs.jafc.0c06485] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Post-mortem (p-m) muscle undergoes a myriad of complex physical and biochemical changes prior to its conversion to meat, which are influential on proteolysis and hence tenderization. A more in-depth understanding of the mechanisms underpinning these dynamics is a key to consistently providing tender beef. Using an LC-MS/MS approach, with state-of-art mass spectrometry Q Exactive HF-X, the proteome and associated pathways contributing to the appearance of the proteolytic breakdown products appearing over 14 days p-m, at two important molecular weights (110 and 30 kDa) on 1D SDS-PAGE gels, have been investigated in beef longissimus thoracis et lumborum muscles exhibiting four rates of pH decline differentiated on the basis of time at pH 6 (fast glycolysing, <3 h; medium, 3-5 h; slow, 5-8 h; and very slow, 8+ h). Both 110 and 30 kDa bands appeared during aging and increased in intensity as a function of p-m time in a pH decline-dependent manner. The 110 kDa band appeared as early as 3 h p-m and displayed an incremental increase in all groups through to 14 days p-m. From 2 days p-m, this increase in abundance during aging was significantly (P < 0.001) influenced by the glycolytic rate: fast > or = medium > slow > very slow. The day 2 p-m appearance of the 30 kDa band was most evident for the fast glycolysing muscle with little or no evidence of appearance in slow and very slow. For days 7 and 14 p-m, the strength of appearance was dependent on glycolysing groups fast > medium > or = slow > very slow. LC-MS/MS analysis yielded a total of 22 unique proteins for the 110 kDa fragment and 13 for the 30 kDa, with 4 common proteins related to both the actin and fibrinogen complex. The Gene Ontology analysis revealed that a myriad of biological pathways are influential with many related to proteins involved primarily in muscle contraction and structure. Other pathways of interest include energy metabolism, apoptotic mitochondrial changes, calcium and ion transport, and so on. Interestingly, most of the proteins composing the fragments were so far identified as biomarkers of beef tenderness and other quality traits.
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Affiliation(s)
- Mohammed Gagaoua
- Food Quality and Sensory Science Department, Teagasc Ashtown Food Research Centre, Ashtown, Dublin 15, Ireland
| | - Declan Troy
- Food Quality and Sensory Science Department, Teagasc Ashtown Food Research Centre, Ashtown, Dublin 15, Ireland
| | - Anne Maria Mullen
- Food Quality and Sensory Science Department, Teagasc Ashtown Food Research Centre, Ashtown, Dublin 15, Ireland
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41
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Li Y, Hessel AL, Unger A, Ing D, Recker J, Koser F, Freundt JK, Linke WA. Graded titin cleavage progressively reduces tension and uncovers the source of A-band stability in contracting muscle. eLife 2020; 9:64107. [PMID: 33357376 PMCID: PMC7781594 DOI: 10.7554/elife.64107] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022] Open
Abstract
The giant muscle protein titin is a major contributor to passive force; however, its role in active force generation is unresolved. Here, we use a novel titin-cleavage (TC) mouse model that allows specific and rapid cutting of elastic titin to quantify how titin-based forces define myocyte ultrastructure and mechanics. We show that under mechanical strain, as TC doubles from heterozygous to homozygous TC muscles, Z-disks become increasingly out of register while passive and active forces are reduced. Interactions of elastic titin with sarcomeric actin filaments are revealed. Strikingly, when titin-cleaved muscles contract, myosin-containing A-bands become split and adjacent myosin filaments move in opposite directions while also shedding myosins. This establishes intact titin filaments as critical force-transmission networks, buffering the forces observed by myosin filaments during contraction. To perform this function, elastic titin must change stiffness or extensible length, unveiling its fundamental role as an activation-dependent spring in contracting muscle.
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Affiliation(s)
- Yong Li
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Anthony L Hessel
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Andreas Unger
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - David Ing
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Jannik Recker
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Franziska Koser
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - 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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42
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Auxerre-Plantié E, Nielsen T, Grunert M, Olejniczak O, Perrot A, Özcelik C, Harries D, Matinmehr F, Dos Remedios C, Mühlfeld C, Kraft T, Bodmer R, Vogler G, Sperling SR. Identification of MYOM2 as a candidate gene in hypertrophic cardiomyopathy and Tetralogy of Fallot, and its functional evaluation in the Drosophila heart. Dis Model Mech 2020; 13:dmm045377. [PMID: 33033063 PMCID: PMC7758640 DOI: 10.1242/dmm.045377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 10/01/2020] [Indexed: 01/11/2023] Open
Abstract
The causal genetic underpinnings of congenital heart diseases, which are often complex and multigenic, are still far from understood. Moreover, there are also predominantly monogenic heart defects, such as cardiomyopathies, with known disease genes for the majority of cases. In this study, we identified mutations in myomesin 2 (MYOM2) in patients with Tetralogy of Fallot (TOF), the most common cyanotic heart malformation, as well as in patients with hypertrophic cardiomyopathy (HCM), who do not exhibit any mutations in the known disease genes. MYOM2 is a major component of the myofibrillar M-band of the sarcomere, and a hub gene within interactions of sarcomere genes. We show that patient-derived cardiomyocytes exhibit myofibrillar disarray and reduced passive force with increasing sarcomere lengths. Moreover, our comprehensive functional analyses in the Drosophila animal model reveal that the so far uncharacterized fly gene CG14964 [herein referred to as Drosophila myomesin and myosin binding protein (dMnM)] may be an ortholog of MYOM2, as well as other myosin binding proteins. Its partial loss of function or moderate cardiac knockdown results in cardiac dilation, whereas more severely reduced function causes a constricted phenotype and an increase in sarcomere myosin protein. Moreover, compound heterozygous combinations of CG14964 and the sarcomere gene Mhc (MYH6/7) exhibited synergistic genetic interactions. In summary, our results suggest that MYOM2 not only plays a critical role in maintaining robust heart function but may also be a candidate gene for heart diseases such as HCM and TOF, as it is clearly involved in the development of the heart.This article has an associated First Person interview with Emilie Auxerre-Plantié and Tanja Nielsen, joint first authors of the paper.
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Affiliation(s)
- Emilie Auxerre-Plantié
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Tanja Nielsen
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Marcel Grunert
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Olga Olejniczak
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Andreas Perrot
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
| | - Cemil Özcelik
- Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
| | - Dennis Harries
- Medical School of Hannover, Institute of Molecular and Cell Physiology, 30625 Hannover, Germany
| | - Faramarz Matinmehr
- Medical School of Hannover, Institute of Molecular and Cell Physiology, 30625 Hannover, Germany
| | - Cristobal Dos Remedios
- Anatomy and Histology, School of Medical Sciences, Bosch Institute, University of Sydney, Camperdown, Sydney, New South Wales 2006, Australia
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Theresia Kraft
- Medical School of Hannover, Institute of Molecular and Cell Physiology, 30625 Hannover, Germany
| | - Rolf Bodmer
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Georg Vogler
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Silke R Sperling
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
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Ghosh AC, Tattikota SG, Liu Y, Comjean A, Hu Y, Barrera V, Ho Sui SJ, Perrimon N. Drosophila PDGF/VEGF signaling from muscles to hepatocyte-like cells protects against obesity. eLife 2020; 9:56969. [PMID: 33107824 PMCID: PMC7752135 DOI: 10.7554/elife.56969] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/26/2020] [Indexed: 12/21/2022] Open
Abstract
PDGF/VEGF ligands regulate a plethora of biological processes in multicellular organisms via autocrine, paracrine, and endocrine mechanisms. We investigated organ-specific metabolic roles of Drosophila PDGF/VEGF-like factors (Pvfs). We combine genetic approaches and single-nuclei sequencing to demonstrate that muscle-derived Pvf1 signals to the Drosophila hepatocyte-like cells/oenocytes to suppress lipid synthesis by activating the Pi3K/Akt1/TOR signaling cascade in the oenocytes. Functionally, this signaling axis regulates expansion of adipose tissue lipid stores in newly eclosed flies. Flies emerge after pupation with limited adipose tissue lipid stores and lipid level is progressively accumulated via lipid synthesis. We find that adult muscle-specific expression of pvf1 increases rapidly during this stage and that muscle-to-oenocyte Pvf1 signaling inhibits expansion of adipose tissue lipid stores as the process reaches completion. Our findings provide the first evidence in a metazoan of a PDGF/VEGF ligand acting as a myokine that regulates systemic lipid homeostasis by activating TOR in hepatocyte-like cells.
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Affiliation(s)
- Arpan C Ghosh
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, United States
| | - Sudhir Gopal Tattikota
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, United States
| | - Yifang Liu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, United States
| | - Aram Comjean
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, United States
| | - Yanhui Hu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, United States
| | - Victor Barrera
- Harvard Chan Bioinformatics Core, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Shannan J Ho Sui
- Harvard Chan Bioinformatics Core, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, United States.,Howard Hughes Medical Institute, Boston, United States
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Cao T, Jin JP. Evolution of Flight Muscle Contractility and Energetic Efficiency. Front Physiol 2020; 11:1038. [PMID: 33162892 PMCID: PMC7581897 DOI: 10.3389/fphys.2020.01038] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 07/29/2020] [Indexed: 12/19/2022] Open
Abstract
The powered flight of animals requires efficient and sustainable contractions of the wing muscles of various flying species. Despite their high degree of phylogenetic divergence, flight muscles in insects and vertebrates are striated muscles with similarly specialized sarcomeric structure and basic mechanisms of contraction and relaxation. Comparative studies examining flight muscles together with other striated muscles can provide valuable insights into the fundamental mechanisms of muscle contraction and energetic efficiency. Here, we conducted a literature review and data mining to investigate the independent emergence and evolution of flight muscles in insects, birds, and bats, and the likely molecular basis of their contractile features and energetic efficiency. Bird and bat flight muscles have different metabolic rates that reflect differences in energetic efficiencies while having similar contractile machinery that is under the selection of similar natural environments. The significantly lower efficiency of insect flight muscles along with minimized energy expenditure in Ca2+ handling is discussed as a potential mechanism to increase the efficiency of mammalian striated muscles. A better understanding of the molecular evolution of myofilament proteins in the context of physiological functions of invertebrate and vertebrate flight muscles can help explore novel approaches to enhance the performance and efficiency of skeletal and cardiac muscles for the improvement of human health.
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Affiliation(s)
| | - J.-P. Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, United States
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Diurnal Differences in Human Muscle Isometric Force In Vivo Are Associated with Differential Phosphorylation of Sarcomeric M-Band Proteins. Proteomes 2020; 8:proteomes8030022. [PMID: 32859009 PMCID: PMC7565642 DOI: 10.3390/proteomes8030022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/06/2020] [Accepted: 08/25/2020] [Indexed: 12/25/2022] Open
Abstract
We investigated whether diurnal differences in muscle force output are associated with the post-translational state of muscle proteins. Ten physically active men (mean ± SD; age 26.7 ± 3.7 y) performed experimental sessions in the morning (08:00 h) and evening (17:00 h), which were counterbalanced in order of administration and separated by at least 72 h. Knee extensor maximal voluntary isometric contraction (MVIC) force and peak rate of force development (RFD) were measured, and samples of vastus lateralis were collected immediately after exercise. MVIC force was greater in the evening (mean difference of 67 N, 10.2%; p < 0.05). Two-dimensional (2D) gel analysis encompassed 122 proteoforms and discovered 6 significant (p < 0.05; false discovery rate [FDR] = 10%) diurnal differences. Phosphopeptide analysis identified 1693 phosphopeptides and detected 140 phosphopeptides from 104 proteins that were more (p < 0.05, FDR = 22%) phosphorylated in the morning. Myomesin 2, muscle creatine kinase, and the C-terminus of titin exhibited the most robust (FDR < 10%) diurnal differences. Exercise in the morning, compared to the evening, coincided with a greater phosphorylation of M-band-associated proteins in human muscle. These protein modifications may alter the M-band structure and disrupt force transmission, thus potentially explaining the lower force output in the morning.
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Berciano MT, Castillo-Iglesias MS, Val-Bernal JF, Lafarga V, Rodriguez-Rey JC, Lafarga M, Tapia O. Mislocalization of SMN from the I-band and M-band in human skeletal myofibers in spinal muscular atrophy associates with primary structural alterations of the sarcomere. Cell Tissue Res 2020; 381:461-478. [PMID: 32676861 DOI: 10.1007/s00441-020-03236-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/05/2020] [Indexed: 12/22/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by a deletion or mutation of the survival motor neuron 1 (SMN1) gene. Reduced SMN levels lead to motor neuron degeneration and muscular atrophy. SMN protein localizes to the cytoplasm and Cajal bodies. Moreover, in myofibrils from Drosophila and mice, SMN is a sarcomeric protein localized to the Z-disc. Although SMN participates in multiple functions, including the biogenesis of spliceosomal small nuclear ribonucleoproteins, its role in the sarcomere is unclear. Here, we analyzed the sarcomeric organization of SMN in human control and type I SMA skeletal myofibers. In control sarcomeres, we demonstrate that human SMN is localized to the titin-positive M-band and actin-positive I-band, and to SMN-positive granules that flanked the Z-discs. Co-immunoprecipitation assays revealed that SMN interacts with the sarcomeric protein actin, α-actinin, titin, and profilin2. In the type I SMA muscle, SMN levels were reduced, and atrophic (denervated) and hypertrophic (nondenervated) myofibers coexisted. The hypertrophied myofibers, which are potential primary targets of SMN deficiency, exhibited sites of focal or segmental alterations of the actin cytoskeleton, where the SMN immunostaining pattern was altered. Moreover, SMN was relocalized to the Z-disc in overcontracted minisarcomeres from hypertrophic myofibers. We propose that SMN could have an integrating role in the molecular components of the sarcomere. Consequently, low SMN levels might impact the normal sarcomeric architecture, resulting in the disruption of myofibrils found in SMA muscle. This primary effect might be independent of the neurogenic myopathy produced by denervation and contribute to pathophysiology of the SMA myopathy.
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Affiliation(s)
- María T Berciano
- Departamento de Biología Molecular, Universidad de Cantabria-IDIVAL, Santander, Spain
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL) and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain
| | | | - J Fernando Val-Bernal
- Unidad de Patología, Departamento de Ciencias Médicas y Quirúrgicas, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - Vanesa Lafarga
- Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
| | - José C Rodriguez-Rey
- Departamento de Biología Molecular, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - Miguel Lafarga
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL) and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain.
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria-IDIVAL, Santander, Spain.
| | - Olga Tapia
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL) and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain.
- Universidad Europea del Atlántico, Santander, Spain.
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The intercalated disc: a mechanosensing signalling node in cardiomyopathy. Biophys Rev 2020; 12:931-946. [PMID: 32661904 PMCID: PMC7429531 DOI: 10.1007/s12551-020-00737-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/08/2020] [Indexed: 02/08/2023] Open
Abstract
Cardiomyocytes, the cells generating contractile force in the heart, are connected to each other through a highly specialised structure, the intercalated disc (ID), which ensures force transmission and transduction between neighbouring cells and allows the myocardium to function in synchrony. In addition, cardiomyocytes possess an intrinsic ability to sense mechanical changes and to regulate their own contractile output accordingly. To achieve this, some of the components responsible for force transmission have evolved to sense changes in tension and to trigger a biochemical response that results in molecular and cellular changes in cardiomyocytes. This becomes of particular importance in cardiomyopathies, where the heart is exposed to increased mechanical load and needs to adapt to sustain its contractile function. In this review, we will discuss key mechanosensing elements present at the intercalated disc and provide an overview of the signalling molecules involved in mediating the responses to changes in mechanical force.
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Tang M, Dai H, Ma L, Yu Y, Liu T, Feng X, Hu W, Li Y, Zhang Y. Degradation of structural proteins and their relationship with the quality of Mandarin fish (
Siniperca chuatsi
) during post‐mortem storage and cooking. Int J Food Sci Technol 2020. [DOI: 10.1111/ijfs.14421] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Mi Tang
- College of Food Science Southwest University Chongqing 400715 China
| | - Hongjie Dai
- College of Food Science Southwest University Chongqing 400715 China
- Chongqing Key Laboratory of Soft‐Matter Material Chemistry and Function Manufacturing Chongqing China
| | - Liang Ma
- College of Food Science Southwest University Chongqing 400715 China
- Biological Science Research Center of Southwest University Chongqing China
| | - Yong Yu
- College of Food Science Southwest University Chongqing 400715 China
| | - Tingwei Liu
- College of Food Science Southwest University Chongqing 400715 China
| | - Xin Feng
- College of Food Science Southwest University Chongqing 400715 China
| | - Weijie Hu
- College of Food Science Southwest University Chongqing 400715 China
| | - Yuan Li
- College of Food Science Southwest University Chongqing 400715 China
| | - Yuhao Zhang
- College of Food Science Southwest University Chongqing 400715 China
- Chongqing Key Laboratory of Soft‐Matter Material Chemistry and Function Manufacturing Chongqing China
- Biological Science Research Center of Southwest University Chongqing China
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Ma W, Lee KH, Yang S, Irving TC, Craig R. Lattice arrangement of myosin filaments correlates with fiber type in rat skeletal muscle. J Gen Physiol 2019; 151:1404-1412. [PMID: 31699797 PMCID: PMC6888752 DOI: 10.1085/jgp.201912460] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/09/2019] [Indexed: 12/22/2022] Open
Abstract
The thick (myosin-containing) filaments of vertebrate skeletal muscle are arranged in a hexagonal lattice, interleaved with an array of thin (actin-containing) filaments with which they interact to produce contraction. X-ray diffraction and EM have shown that there are two types of thick filament lattice. In the simple lattice, all filaments have the same orientation about their long axis, while in the superlattice, nearest neighbors have rotations differing by 0° or 60°. Tetrapods (amphibians, reptiles, birds, and mammals) typically have only a superlattice, while the simple lattice is confined to fish. We have performed x-ray diffraction and electron microscopy of the soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat and found that while the EDL has a superlattice as expected, the SOL has a simple lattice. The EDL and SOL of the rat are unusual in being essentially pure fast and slow muscles, respectively. The mixed fiber content of most tetrapod muscles and/or lattice disorder may explain why the simple lattice has not been apparent in these vertebrates before. This is supported by only weak simple lattice diffraction in the x-ray pattern of mouse SOL, which has a greater mix of fiber types than rat SOL. We conclude that the simple lattice might be common in tetrapods. The correlation between fiber type and filament lattice arrangement suggests that the lattice arrangement may contribute to the functional properties of a muscle.
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Affiliation(s)
- Weikang Ma
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL
| | - Kyoung Hwan Lee
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Shixin Yang
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Thomas C Irving
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL
| | - Roger Craig
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
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50
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Special Issue: The Actin-Myosin Interaction in Muscle: Background and Overview. Int J Mol Sci 2019; 20:ijms20225715. [PMID: 31739584 PMCID: PMC6887992 DOI: 10.3390/ijms20225715] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 10/15/2019] [Indexed: 12/12/2022] Open
Abstract
Muscular contraction is a fundamental phenomenon in all animals; without it life as we know it would be impossible. The basic mechanism in muscle, including heart muscle, involves the interaction of the protein filaments myosin and actin. Motility in all cells is also partly based on similar interactions of actin filaments with non-muscle myosins. Early studies of muscle contraction have informed later studies of these cellular actin-myosin systems. In muscles, projections on the myosin filaments, the so-called myosin heads or cross-bridges, interact with the nearby actin filaments and, in a mechanism powered by ATP-hydrolysis, they move the actin filaments past them in a kind of cyclic rowing action to produce the macroscopic muscular movements of which we are all aware. In this special issue the papers and reviews address different aspects of the actin-myosin interaction in muscle as studied by a plethora of complementary techniques. The present overview provides a brief and elementary introduction to muscle structure and function and the techniques used to study it. It goes on to give more detailed descriptions of what is known about muscle components and the cross-bridge cycle using structural biology techniques, particularly protein crystallography, electron microscopy and X-ray diffraction. It then has a quick look at muscle mechanics and it summarises what can be learnt about how muscle works based on the other studies covered in the different papers in the special issue. A picture emerges of the main molecular steps involved in the force-producing process; steps that are also likely to be seen in non-muscle myosin interactions with cellular actin filaments. Finally, the remarkable advances made in studying the effects of mutations in the contractile assembly in causing specific muscle diseases, particularly those in heart muscle, are outlined and discussed.
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