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Strom J, Bull M, Gohlke J, Saripalli C, Methawasin M, Gotthardt M, Granzier H. Titin's cardiac-specific N2B element is critical to mechanotransduction during volume overload of the heart. J Mol Cell Cardiol 2024; 191:40-49. [PMID: 38604403 DOI: 10.1016/j.yjmcc.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 03/09/2024] [Accepted: 04/08/2024] [Indexed: 04/13/2024]
Abstract
The heart has the ability to detect and respond to changes in mechanical load through a process called mechanotransduction. In this study, we focused on investigating the role of the cardiac-specific N2B element within the spring region of titin, which has been proposed to function as a mechanosensor. To assess its significance, we conducted experiments using N2B knockout (KO) mice and wildtype (WT) mice, subjecting them to three different conditions: 1) cardiac pressure overload induced by transverse aortic constriction (TAC), 2) volume overload caused by aortocaval fistula (ACF), and 3) exercise-induced hypertrophy through swimming. Under conditions of pressure overload (TAC), both genotypes exhibited similar hypertrophic responses. In contrast, WT mice displayed robust left ventricular hypertrophy after one week of volume overload (ACF), while the KO mice failed to undergo hypertrophy and experienced a high mortality rate. Similarly, swim exercise-induced hypertrophy was significantly reduced in the KO mice. RNA-Seq analysis revealed an abnormal β-adrenergic response to volume overload in the KO mice, as well as a diminished response to isoproterenol-induced hypertrophy. Because it is known that the N2B element interacts with the four-and-a-half LIM domains 1 and 2 (FHL1 and FHL2) proteins, both of which have been associated with mechanotransduction, we evaluated these proteins. Interestingly, while volume-overload resulted in FHL1 protein expression levels that were comparable between KO and WT mice, FHL2 protein levels were reduced by over 90% in the KO mice compared to WT. This suggests that in response to volume overload, FHL2 might act as a signaling mediator between the N2B element and downstream signaling pathways. Overall, our study highlights the importance of the N2B element in mechanosensing during volume overload, both in physiological and pathological settings.
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Affiliation(s)
- Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States of America
| | - Mathew Bull
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States of America
| | - Jochen Gohlke
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States of America
| | - Chandra Saripalli
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States of America
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States of America
| | - Michael Gotthardt
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Cardiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America.
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Stroik D, Gregorich ZR, Raza F, Ge Y, Guo W. Titin: roles in cardiac function and diseases. Front Physiol 2024; 15:1385821. [PMID: 38660537 PMCID: PMC11040099 DOI: 10.3389/fphys.2024.1385821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The giant protein titin is an essential component of muscle sarcomeres. A single titin molecule spans half a sarcomere and mediates diverse functions along its length by virtue of its unique domains. The A-band of titin functions as a molecular blueprint that defines the length of the thick filaments, the I-band constitutes a molecular spring that determines cell-based passive stiffness, and various domains, including the Z-disk, I-band, and M-line, serve as scaffolds for stretch-sensing signaling pathways that mediate mechanotransduction. This review aims to discuss recent insights into titin's functional roles and their relationship to cardiac function. The role of titin in heart diseases, such as dilated cardiomyopathy and heart failure with preserved ejection fraction, as well as its potential as a therapeutic target, is also discussed.
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Affiliation(s)
- Dawson Stroik
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Zachery R. Gregorich
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Farhan Raza
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Ying Ge
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Wei Guo
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
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3
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Usui Y, Hanashima A, Hashimoto K, Kimoto M, Ohira M, Mohri S. Comparative analysis of ventricular stiffness across species. Physiol Rep 2024; 12:e16013. [PMID: 38644486 PMCID: PMC11033294 DOI: 10.14814/phy2.16013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 04/01/2024] [Accepted: 04/01/2024] [Indexed: 04/23/2024] Open
Abstract
Investigating ventricular diastolic properties is crucial for understanding the physiological cardiac functions in organisms and unraveling the pathological mechanisms of cardiovascular disorders. Ventricular stiffness, a fundamental parameter that defines ventricular diastolic functions in chordates, is typically analyzed using the end-diastolic pressure-volume relationship (EDPVR). However, comparing ventricular stiffness accurately across chambers of varying maximum volume capacities has been a long-standing challenge. As one of the solutions to this problem, we propose calculating a relative ventricular stiffness index by applying an exponential approximation formula to the EDPVR plot data of the relationship between ventricular pressure and values of normalized ventricular volume by the ventricular weight. This article reviews the potential, utility, and limitations of using normalized EDPVR analysis in recent studies. Herein, we measured and ranked ventricular stiffness in differently sized and shaped chambers using ex vivo ventricular pressure-volume analysis data from four animals: Wistar rats, red-eared slider turtles, masu salmon, and cherry salmon. Furthermore, we have discussed the mechanical effects of intracellular and extracellular viscoelastic components, Titin (Connectin) filaments, collagens, physiological sarcomere length, and other factors that govern ventricular stiffness. Our review provides insights into the comparison of ventricular stiffness in different-sized ventricles between heterologous and homologous species, including non-model organisms.
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Grants
- JP22K15155 Japan Society for the Promotion of Science, Grant/Award Number
- JP20K21453 Japan Society for the Promotion of Science, Grant/Award Number
- JP20H04508 Japan Society for the Promotion of Science, Grant/Award Number
- JP21K19933 Japan Society for the Promotion of Science, Grant/Award Number
- JP20H04521 Japan Society for the Promotion of Science, Grant/Award Number
- JP17H02092 Japan Society for the Promotion of Science, Grant/Award Number
- JP23H00556 Japan Society for the Promotion of Science, Grant/Award Number
- JP17H06272 Japan Society for the Promotion of Science, Grant/Award Number
- JP17H00859 Japan Society for the Promotion of Science, Grant/Award Number
- JP25560214 Japan Society for the Promotion of Science, Grant/Award Number
- JP16K01385 Japan Society for the Promotion of Science, Grant/Award Number
- JP26282127 Japan Society for the Promotion of Science, Grant/Award Number
- The Futaba research grant program
- Research Grant from the Kawasaki Foundation in 2016 from Medical Science and Medical Welfare
- Medical Research Grant in 2010 from Takeda Science Foundation
- R03S005 Research Project Grant from Kawasaki Medical School
- R03B050 Research Project Grant from Kawasaki Medical School
- R01B054 Research Project Grant from Kawasaki Medical School
- H30B041 Research Project Grant from Kawasaki Medical School
- H30B016 Research Project Grant from Kawasaki Medical School
- H27B10 Research Project Grant from Kawasaki Medical School
- R02B039 Research Project Grant from Kawasaki Medical School
- H28B80 Research Project Grant from Kawasaki Medical School
- R05B016 Research Project Grant from Kawasaki Medical School
- Japan Society for the Promotion of Science, Grant/Award Number
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Affiliation(s)
- Yuu Usui
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Akira Hanashima
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Ken Hashimoto
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Misaki Kimoto
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Momoko Ohira
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
| | - Satoshi Mohri
- First Department of PhysiologyKawasaki Medical SchoolKurashikiOkayamaJapan
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Hinson JT, Hershberger RE. Monoallelic TTN Truncation Variants Identified in Individuals With DCM May Cause a Mild Skeletal Myopathy. JACC. HEART FAILURE 2024; 12:754-756. [PMID: 38206233 DOI: 10.1016/j.jchf.2023.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 01/12/2024]
Affiliation(s)
- J Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA; Cardiology Center, UConn Health, Farmington, Connecticut, USA.
| | - Ray E Hershberger
- Divisions of Human Genetics and Cardiovascular Medicine, Department of Medicine, The Ohio State University Medical Center, Columbus, Ohio, USA; The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, USA
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5
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Jolfayi AG, Kohansal E, Ghasemi S, Naderi N, Hesami M, MozafaryBazargany M, Moghadam MH, Fazelifar AF, Maleki M, Kalayinia S. Exploring TTN variants as genetic insights into cardiomyopathy pathogenesis and potential emerging clues to molecular mechanisms in cardiomyopathies. Sci Rep 2024; 14:5313. [PMID: 38438525 PMCID: PMC10912352 DOI: 10.1038/s41598-024-56154-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/01/2024] [Indexed: 03/06/2024] Open
Abstract
The giant protein titin (TTN) is a sarcomeric protein that forms the myofibrillar backbone for the components of the contractile machinery which plays a crucial role in muscle disorders and cardiomyopathies. Diagnosing TTN pathogenic variants has important implications for patient management and genetic counseling. Genetic testing for TTN variants can help identify individuals at risk for developing cardiomyopathies, allowing for early intervention and personalized treatment strategies. Furthermore, identifying TTN variants can inform prognosis and guide therapeutic decisions. Deciphering the intricate genotype-phenotype correlations between TTN variants and their pathologic traits in cardiomyopathies is imperative for gene-based diagnosis, risk assessment, and personalized clinical management. With the increasing use of next-generation sequencing (NGS), a high number of variants in the TTN gene have been detected in patients with cardiomyopathies. However, not all TTN variants detected in cardiomyopathy cohorts can be assumed to be disease-causing. The interpretation of TTN variants remains challenging due to high background population variation. This narrative review aimed to comprehensively summarize current evidence on TTN variants identified in published cardiomyopathy studies and determine which specific variants are likely pathogenic contributors to cardiomyopathy development.
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Affiliation(s)
- Amir Ghaffari Jolfayi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Erfan Kohansal
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Serwa Ghasemi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Niloofar Naderi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahshid Hesami
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | | | - Maryam Hosseini Moghadam
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Amir Farjam Fazelifar
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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6
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Sun W, Liu X, Song L, Tao L, Lai K, Jiang H, Xiao H. The TTN p. Tyr4418Ter mutation causes cardiomyopathy in human and mice. PLoS One 2024; 19:e0296802. [PMID: 38381767 PMCID: PMC10880961 DOI: 10.1371/journal.pone.0296802] [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: 10/03/2023] [Accepted: 12/19/2023] [Indexed: 02/23/2024] Open
Abstract
OBJECTIVE To generate a mouse model carrying TTNtv Y4370* simulating the newly discovered human heterozygous nonsense TTNtv c.13254T>G (p.Tyr4418Ter) to supplement and improve the functional evidence of pathogenic mutation TTNtv c.13254T>G on the pathogenic type of dilated cardiomyopathy. METHODS We generated 4 mice carrying TTNtv p. Y4370* through CRISPR/Cas-mediated genome engineering. Monthly serological detection, bimonthly echocardiography, and histology evaluation were carried out to observe and compare alterations of cardiac structure and function between 4 TTN+/- mice and 4 wild-type (WT) mice. RESULTS For the two-month-old TTN+/- mice, serum glutamic-oxalacetic transaminase (AST), lactic dehydrogenase (LDH), and creatine kinase (CK) were significantly increased, the diastolic Left Ventricular Systolic Anterior Wall (LVAW), and the LV mass markedly rose, with the left ventricular volume displaying an increasing trend and Ejection Fraction (EF) and Fractional Shortening (FS) showing a decreasing trend. Besides, the histological evaluation showed that cardiac fibrosis level and positive rate of cardiac mast cell of TTN+/- mice were obviously increased compared with WT mice. CONCLUSIONS TTNtv Y4370* could lead to cardiac structure and function alterations in mice, supplementing the evidence of TTNtv c.13254T>G pathogenicity in human.
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Affiliation(s)
- Wenqiang Sun
- Division of Cardiac Surgery & Wuhan Clinical Research Center for Cardiomyopathy, Wuhan Asia Heart Hospital Affiliated with Wuhan University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Xiaohui Liu
- Department of Clinical Laboratory, Wuhan Asia Heart Hospital Affiliated with the Wuhan University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Laichun Song
- Division of Cardiac Surgery & Wuhan Clinical Research Center for Cardiomyopathy, Wuhan Asia Heart Hospital Affiliated with Wuhan University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Liang Tao
- Division of Cardiac Surgery & Wuhan Clinical Research Center for Cardiomyopathy, Wuhan Asia Heart Hospital Affiliated with Wuhan University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Kaisheng Lai
- Department of Science Research Centre, BestNovo (Beijing) Medical Laboratory, Beijing, P.R. China
| | - Hui Jiang
- Department of Science Research Centre, BestNovo (Beijing) Medical Laboratory, Beijing, P.R. China
| | - Hongyan Xiao
- Division of Cardiac Surgery & Wuhan Clinical Research Center for Cardiomyopathy, Wuhan Asia Heart Hospital Affiliated with Wuhan University of Science and Technology, Wuhan, Hubei, P.R. China
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7
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ElSaygh J, Zaher A, Peterson SJ, Parikh MA, Frishman WH. Titin: The Missing Link in Cardiac Physiology. Cardiol Rev 2024:00045415-990000000-00209. [PMID: 38334419 DOI: 10.1097/crd.0000000000000656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Titin, an extraordinary protein known for its colossal size and multifaceted roles, is a cornerstone in the structural and functional dynamics of striated muscle tissues, including the heart and skeletal muscles. Its sheer enormity, with a molecular weight exceeding 3000 kDa, is paralleled only by the immense influence it exerts on muscle physiology. This review will delve into the remarkable structural organization of Titin and the genetics of this molecule, including the common mutations resulting in various cardiomyopathies. We will delve deeper into its role in dilated cardiomyopathy, familial restrictive cardiomyopathy, hypertrophic cardiomyopathy, and left ventricular noncompaction cardiomyopathy. This review culminates by discussing the prospects of therapeutic strategies targeting Titin. While these interventions remain primarily theoretical, the possibilities are intriguing. Patients with Titin truncation mutations present unique challenges, but innovative approaches like gene therapy or preemptive treatments with drugs such as angiotensin-converting enzyme inhibitors or beta-blockers offer hope. This multi-pronged approach highlights the significance of understanding Titin's multifaceted role and its potential as a target for future therapeutic interventions.
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Affiliation(s)
- Jude ElSaygh
- From the Department of Medicine, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY
| | - Anas Zaher
- From the Department of Medicine, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY
| | - Stephen J Peterson
- From the Department of Medicine, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY
- Weill Department of Medicine, Weill Cornell Medicine, NY
| | - Manish A Parikh
- From the Department of Medicine, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY
- Weill Department of Medicine, Weill Cornell Medicine, NY
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Kahsay A, Dennhag N, Liu JX, Nord H, Rönnbäck H, Thorell AE, von Hofsten J, Pedrosa Domellöf F. Obscurin Maintains Myofiber Identity in Extraocular Muscles. Invest Ophthalmol Vis Sci 2024; 65:19. [PMID: 38334702 PMCID: PMC10860686 DOI: 10.1167/iovs.65.2.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/12/2024] [Indexed: 02/10/2024] Open
Abstract
Purpose The cytoskeleton of the extraocular muscles (EOMs) is significantly different from that of other muscles. We aimed to investigate the role of obscurin, a fundamental cytoskeletal protein, in the EOMs. Methods The distribution of obscurin in human and zebrafish EOMs was compared using immunohistochemistry. The two obscurin genes in zebrafish, obscna and obscnb, were knocked out using CRISPR/Cas9, and the EOMs were investigated using immunohistochemistry, qPCR, and in situ hybridization. The optokinetic reflex (OKR) in five-day-old larvae and adult obscna-/-;obscnb-/- and sibling control zebrafish was analyzed. Swimming distance was recorded at the same age. Results The obscurin distribution pattern was similar in human and zebrafish EOMs. The proportion of slow and fast myofibers was reduced in obscna-/-;obscnb-/- zebrafish EOMs but not in trunk muscle, whereas the number of myofibers containing cardiac myosin myh7 was significantly increased in EOMs of obscurin double mutants. Loss of obscurin resulted in less OKRs in zebrafish larvae but not in adult zebrafish. Conclusions Obscurin expression is conserved in normal human and zebrafish EOMs. Loss of obscurin induces a myofiber type shift in the EOMs, with upregulation of cardiac myosin heavy chain, myh7, showing an adaptation strategy in EOMs. Our model will facilitate further studies in conditions related to obscurin.
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Affiliation(s)
- Abraha Kahsay
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Nils Dennhag
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Jing-Xia Liu
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
| | - Hanna Nord
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
| | - Hugo Rönnbäck
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | | | - Jonas von Hofsten
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
| | - Fatima Pedrosa Domellöf
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
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9
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Fallon TR, Shende VV, Wierzbicki IH, Auber RP, Gonzalez DJ, Wisecaver JH, Moore BS. Giant polyketide synthase enzymes biosynthesize a giant marine polyether biotoxin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.29.577497. [PMID: 38352448 PMCID: PMC10862718 DOI: 10.1101/2024.01.29.577497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Prymnesium parvum are harmful haptophyte algae that cause massive environmental fish-kills. Their polyketide polyether toxins, the prymnesins, are amongst the largest nonpolymeric compounds in nature, alongside structurally-related health-impacting "red-tide" polyether toxins whose biosynthetic origins have been an enigma for over 40 years. Here we report the 'PKZILLAs', massive P. parvum polyketide synthase (PKS) genes, whose existence and challenging genomic structure evaded prior detection. PKZILLA-1 and -2 encode giant protein products of 4.7 and 3.2 MDa with 140 and 99 enzyme domains, exceeding the largest known protein titin and all other known PKS systems. Their predicted polyene product matches the proposed pre-prymnesin precursor of the 90-carbon-backbone A-type prymnesins. This discovery establishes a model system for microalgal polyether biosynthesis and expands expectations of genetic and enzymatic size limits in biology.
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Affiliation(s)
- Timothy R. Fallon
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and University of California, San Diego; 9500 Gilman Dr #0204, La Jolla, CA 92093, USA
| | - Vikram V. Shende
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and University of California, San Diego; 9500 Gilman Dr #0204, La Jolla, CA 92093, USA
| | - Igor H. Wierzbicki
- Department of Pharmacology, University of California, San Diego; 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Robert P. Auber
- Department of Biochemistry, Purdue University; 175 S University St, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University; 175 S University St, West Lafayette, IN 47907, USA
| | - David J. Gonzalez
- Department of Pharmacology, University of California, San Diego; 9500 Gilman Dr, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego; 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Jennifer H. Wisecaver
- Department of Biochemistry, Purdue University; 175 S University St, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University; 175 S University St, West Lafayette, IN 47907, USA
| | - Bradley S. Moore
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and University of California, San Diego; 9500 Gilman Dr #0204, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego; 9500 Gilman Dr, La Jolla, CA 92093, USA
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Kellermayer D, Tordai H, Kiss B, Török G, Péter DM, Sayour AA, Pólos M, Hartyánszky I, Szilveszter B, Labeit S, Gángó A, Bedics G, Bödör C, Radovits T, Merkely B, Kellermayer MS. Truncated titin is structurally integrated into the human dilated cardiomyopathic sarcomere. J Clin Invest 2024; 134:e169753. [PMID: 37962957 PMCID: PMC10763722 DOI: 10.1172/jci169753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/08/2023] [Indexed: 11/16/2023] Open
Abstract
Heterozygous (HET) truncating variant mutations in the TTN gene (TTNtvs), encoding the giant titin protein, are the most common genetic cause of dilated cardiomyopathy (DCM). However, the molecular mechanisms by which TTNtv mutations induce DCM are controversial. Here, we studied 127 clinically identified DCM human cardiac samples with next-generation sequencing (NGS), high-resolution gel electrophoresis, Western blot analysis, and super-resolution microscopy in order to dissect the structural and functional consequences of TTNtv mutations. The occurrence of TTNtv was found to be 15% in the DCM cohort. Truncated titin proteins matching, by molecular weight, the gene sequence predictions were detected in the majority of the TTNtv+ samples. Full-length titin was reduced in TTNtv+ compared with TTNtv- samples. Proteomics analysis of washed myofibrils and stimulated emission depletion (STED) super-resolution microscopy of myocardial sarcomeres labeled with sequence-specific anti-titin antibodies revealed that truncated titin was structurally integrated into the sarcomere. Sarcomere length-dependent anti-titin epitope position, shape, and intensity analyses pointed at possible structural defects in the I/A junction and the M-band of TTNtv+ sarcomeres, which probably contribute, possibly via faulty mechanosensor function, to the development of manifest DCM.
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Affiliation(s)
- Dalma Kellermayer
- Heart and Vascular Center
- Department of Biophysics and Radiation Biology, and
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | | | - Balázs Kiss
- Department of Biophysics and Radiation Biology, and
| | - György Török
- Department of Biophysics and Radiation Biology, and
| | | | | | | | | | | | - Siegfried Labeit
- DZHK Partnersite Mannheim-Heidelberg, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ambrus Gángó
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Gábor Bedics
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Csaba Bödör
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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11
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Barefield DY, Tonino P, Woulfe KC, Rahmanseresht S, O’Leary TS, Burnham HV, Wasserstrom JA, Kirk JA, Previs MJ, Granzier HL, McNally EM. Myosin-binding protein H-like regulates myosin-binding protein distribution and function in atrial cardiomyocytes. Proc Natl Acad Sci U S A 2023; 120:e2314920120. [PMID: 38091294 PMCID: PMC10741380 DOI: 10.1073/pnas.2314920120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/25/2023] [Indexed: 12/18/2023] Open
Abstract
Mutations in atrial-enriched genes can cause a primary atrial myopathy that can contribute to overall cardiovascular dysfunction. MYBPHL encodes myosin-binding protein H-like (MyBP-HL), an atrial sarcomere protein that shares domain homology with the carboxy-terminus of cardiac myosin-binding protein-C (cMyBP-C). The function of MyBP-HL and the relationship between MyBP-HL and cMyBP-C is unknown. To decipher the roles of MyBP-HL, we used structured illumination microscopy, immuno-electron microscopy, and mass spectrometry to establish the localization and stoichiometry of MyBP-HL. We found levels of cMyBP-C, a major regulator of myosin function, were half as abundant compared to levels in the ventricle. In genetic mouse models, loss of MyBP-HL doubled cMyBP-C abundance in the atria, and loss of cMyBP-C doubled MyBP-HL abundance in the atria. Structured illumination microscopy showed that both proteins colocalize in the C-zone of the A-band, with MyBP-HL enriched closer to the M-line. Immuno-electron microscopy of mouse atria showed MyBP-HL strongly localized 161 nm from the M-line, consistent with localization to the third 43 nm repeat of myosin heads. Both cMyBP-C and MyBP-HL had less-defined sarcomere localization in the atria compared to ventricle, yet areas with the expected 43 nm repeat distance were observed for both proteins. Isometric force measurements taken from control and Mybphl null single atrial myofibrils revealed that loss of Mybphl accelerated the linear phase of relaxation. These findings support a mechanism where MyBP-HL regulates cMyBP-C abundance to alter the kinetics of sarcomere relaxation in atrial sarcomeres.
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Affiliation(s)
- David Y. Barefield
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Paola Tonino
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO80045
| | - Sheema Rahmanseresht
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Hope V. Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - J. Andrew Wasserstrom
- Department of Medicine and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Jonathan A. Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Henk L. Granzier
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
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12
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Zampieri M, Di Filippo C, Zocchi C, Fico V, Golinelli C, Spaziani G, Calabri G, Bennati E, Girolami F, Marchi A, Passantino S, Porcedda G, Capponi G, Gozzini A, Olivotto I, Ragni L, Favilli S. Focus on Paediatric Restrictive Cardiomyopathy: Frequently Asked Questions. Diagnostics (Basel) 2023; 13:3666. [PMID: 38132249 PMCID: PMC10742619 DOI: 10.3390/diagnostics13243666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/21/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023] Open
Abstract
Restrictive cardiomyopathy (RCM) is characterized by restrictive ventricular pathophysiology determined by increased myocardial stiffness. While suspicion of RCM is initially raised by clinical evaluation and supported by electrocardiographic and echocardiographic findings, invasive hemodynamic evaluation is often required for diagnosis and management of patients during follow-up. RCM is commonly associated with a poor prognosis and a high incidence of heart failure, and PH is reported in paediatric patients with RCM. Currently, only a few therapies are available for specific RCM aetiologies. Early referral to centres for advanced heart failure treatment is often necessary. The aim of this review is to address questions frequently asked when facing paediatric patients with RCM, including issues related to aetiologies, clinical presentation, diagnostic process and prognosis.
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Affiliation(s)
- Mattia Zampieri
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
- Cardiomyopathy Unit, Careggi University Hospital, 50134 Florence, Italy
| | - Chiara Di Filippo
- Local Health Unit, Outpatient Cardiology Clinic, 84131 Salerno, Italy
| | - Chiara Zocchi
- Cardiovascular Department, San Donato Hospital, 52100 Arezzo, Italy
| | - Vera Fico
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
- Cardiomyopathy Unit, Careggi University Hospital, 50134 Florence, Italy
| | - Cristina Golinelli
- Pediatric Cardiology and Adult Congenital Heart Disease Program, Department of Cardio—Thoracic and Vascular Medicine, IRCCS Azienda Ospedaliero—Universitaria di Bologna, 40138 Bologna, Italy
| | - Gaia Spaziani
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Giovanni Calabri
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Elena Bennati
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Francesca Girolami
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Alberto Marchi
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
- Cardiomyopathy Unit, Careggi University Hospital, 50134 Florence, Italy
| | - Silvia Passantino
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Giulio Porcedda
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Guglielmo Capponi
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Alessia Gozzini
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
| | - Iacopo Olivotto
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
- Cardiomyopathy Unit, Careggi University Hospital, 50134 Florence, Italy
| | - Luca Ragni
- Pediatric Cardiology and Adult Congenital Heart Disease Program, Department of Cardio—Thoracic and Vascular Medicine, IRCCS Azienda Ospedaliero—Universitaria di Bologna, 40138 Bologna, Italy
| | - Silvia Favilli
- Pediatric Cardiology, Meyer Children’s University Hospital IRCCS, 50134 Florence, Italy (S.F.)
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13
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Fleming JR, Müller I, Zacharchenko T, Diederichs K, Mayans O. Molecular insights into titin's A-band. J Muscle Res Cell Motil 2023; 44:255-270. [PMID: 37258982 PMCID: PMC10665226 DOI: 10.1007/s10974-023-09649-1] [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: 03/06/2023] [Accepted: 04/11/2023] [Indexed: 06/02/2023]
Abstract
The thick filament-associated A-band region of titin is a highly repetitive component of the titin chain with important scaffolding properties that support thick filament assembly. It also has a demonstrated link to human disease. Despite its functional significance, it remains a largely uncharacterized part of the titin protein. Here, we have performed an analysis of sequence and structure conservation of A-band titin, with emphasis on poly-FnIII tandem components. Specifically, we have applied multi-dimensional sequence pairwise similarity analysis to FnIII domains and complemented this with the crystallographic elucidation of the 3D-structure of the FnIII-triplet A84-A86 from the fourth long super-repeat in the C-zone (C4). Structural models serve here as templates to map sequence conservation onto super-repeat C4, which we show is a prototypical representative of titin's C-zone. This templating identifies positionally conserved residue clusters in C super-repeats with the potential of mediating interactions to thick-filament components. Conservation localizes to two super-repeat positions: Ig domains in position 1 and FnIII domains in position 7. The analysis also allows conclusions to be drawn on the conserved architecture of titin's A-band, as well as revisiting and expanding the evolutionary model of titin's A-band.
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Affiliation(s)
| | - Iljas Müller
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Thomas Zacharchenko
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
- Wellcome Centre for Cell-Matrix Research, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Kay Diederichs
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany.
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14
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Kelly JA, Dinman JD. Shiftless Is a Novel Member of the Ribosome Stress Surveillance Machinery That Has Evolved to Play a Role in Innate Immunity and Cancer Surveillance. Viruses 2023; 15:2296. [PMID: 38140537 PMCID: PMC10747187 DOI: 10.3390/v15122296] [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: 11/06/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
A longstanding paradox in molecular biology has centered on the question of how very long proteins are synthesized, despite numerous measurements indicating that ribosomes spontaneously shift reading frame at rates that should preclude their ability completely translate their mRNAs. Shiftless (SFL; C19orf66) was originally identified as an interferon responsive gene encoding an antiviral protein, indicating that it is part of the innate immune response. This activity is due to its ability to bind ribosomes that have been programmed by viral sequence elements to shift reading frame. Curiously, Shiftless is constitutively expressed at low levels in mammalian cells. This study examines the effects of altering Shiftless homeostasis, revealing how it may be used by higher eukaryotes to identify and remove spontaneously frameshifted ribosomes, resolving the apparent limitation on protein length. Data also indicate that Shiftless plays a novel role in the ribosome-associated quality control program. A model is proposed wherein SFL recognizes and arrests frameshifted ribosomes, and depending on SFL protein concentrations, either leads to removal of frameshifted ribosomes while leaving mRNAs intact, or to mRNA degradation. We propose that SFL be added to the growing pantheon of proteins involved in surveilling translational fidelity and controlling gene expression in higher eukaryotes.
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Affiliation(s)
| | - Jonathan D. Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA;
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15
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Wang G, Wu W, Lv X, Yan C, Lin P. Aberrant mRNA processing caused by splicing mutations in TTN-related neuromuscular disorders. J Hum Genet 2023; 68:777-782. [PMID: 37407718 DOI: 10.1038/s10038-023-01182-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/20/2023] [Accepted: 06/27/2023] [Indexed: 07/07/2023]
Abstract
Mutations in the TTN gene have been reported to be responsible for a range of neuromuscular disorders, including recessive distal myopathy and congenital myopathy (CM). Only five splicing mutations have been identified to induce aberrant mRNA splicing in TTN-related neuromuscular disorders. In our study, we described detailed clinical characteristics, muscle pathology and genetic analysis of two probands with TTN-related autosomal recessive neuromuscular disorders. Besides, we identified two novel intronic mutations, c.107377+1 G > C in intron 362 and c.19994-2 A > G in intron 68, in the two probands. Through cDNA analysis, we revealed the c.107377+1 G > C mutation induced retention of the entire intron 362, and the c.19994-2 A > G mutation triggered skipping of the first 11 bp of exon 69. Our study broadens the aberrant splicing spectrum of neuromuscular disorders caused by splicing mutations in the TTN gene.
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Affiliation(s)
- Guangyu Wang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Wenjing Wu
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Xiaoqing Lv
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Chuanzhu Yan
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Pengfei Lin
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China.
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16
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Inafuku DA, Kirkpatrick KL, Osuagwu O, An Q, Brewster DA, Nakib MZ. Channel capacity of the ribosome. Phys Rev E 2023; 108:044404. [PMID: 37978643 DOI: 10.1103/physreve.108.044404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 08/09/2023] [Indexed: 11/19/2023]
Abstract
Translation is one of the most fundamental processes in the biological cell. Because of the central role that translation plays across all domains of life, the enzyme that carries out this process, the ribosome, is required to process information with high accuracy. This accuracy often approaches values near unity experimentally. In this paper, we model the ribosome as an information channel and demonstrate mathematically that this biological machine has information-processing capabilities that have not been recognized previously. In particular, we calculate bounds on the ribosome's theoretical Shannon capacity and numerically approximate this capacity. Finally, by incorporating estimates on the ribosome's operation time, we show that the ribosome operates at speeds safely below its capacity, allowing the ribosome to process information with an arbitrary degree of error. Our results show that the ribosome achieves a high accuracy in line with purely information-theoretic means.
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Affiliation(s)
- Daniel A Inafuku
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Kay L Kirkpatrick
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Mathematics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Onyema Osuagwu
- Electrical and Computer Engineering Department, Morgan State University, Baltimore, Maryland 21251, USA
- Cybersecurity Assurance and Policy Center, Morgan State University, Baltimore, Maryland 21251, USA
| | - Qier An
- Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - David A Brewster
- Department of Mathematics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Mayisha Zeb Nakib
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
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17
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Gassner C, Vongsvivut J, Ng SH, Ryu M, Tobin MJ, Juodkazis S, Morikawa J, Wood BR. Linearly Polarized Infrared Spectroscopy for the Analysis of Biological Materials. APPLIED SPECTROSCOPY 2023; 77:977-1008. [PMID: 37464791 DOI: 10.1177/00037028231180233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The analysis of biological samples with polarized infrared spectroscopy (p-IR) has long been a widely practiced method for the determination of sample orientation and structural properties. In contrast to earlier works, which employed this method to investigate the fundamental chemistry of biological systems, recent interests are moving toward "real-world" applications for the evaluation and diagnosis of pathological states. This focal point review provides an up-to-date synopsis of the knowledge of biological materials garnered through linearly p-IR on biomolecules, cells, and tissues. An overview of the theory with special consideration to biological samples is provided. Different modalities which can be employed along with their capabilities and limitations are outlined. Furthermore, an in-depth discussion of factors regarding sample preparation, sample properties, and instrumentation, which can affect p-IR analysis is provided. Additionally, attention is drawn to the potential impacts of analysis of biological samples with inherently polarized light sources, such as synchrotron light and quantum cascade lasers. The vast applications of p-IR for the determination of the structure and orientation of biological samples are given. In conclusion, with considerations to emerging instrumentation, findings by other techniques, and the shift of focus toward clinical applications, we speculate on the future directions of this methodology.
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Affiliation(s)
- Callum Gassner
- Centre for Biospectroscopy, School of Chemistry, Monash University, Clayton, Australia
| | - Jitraporn Vongsvivut
- Infrared Microspectroscopy (IRM) Beamline, ANSTO-Australian Synchrotron, Clayton, Australia
| | - Soon Hock Ng
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, Australia
| | - Meguya Ryu
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Mark J Tobin
- Infrared Microspectroscopy (IRM) Beamline, ANSTO-Australian Synchrotron, Clayton, Australia
| | - Saulius Juodkazis
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, Australia
| | - Junko Morikawa
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Bayden R Wood
- Centre for Biospectroscopy, School of Chemistry, Monash University, Clayton, Australia
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18
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Di Feo MF, Lillback V, Jokela M, McEntagart M, Homfray T, Giorgio E, Casalis Cavalchini GC, Brusco A, Iascone M, Spaccini L, D'Oria P, Savarese M, Udd B. The crucial role of titin in fetal development: recurrent miscarriages and bone, heart and muscle anomalies characterise the severe end of titinopathies spectrum. J Med Genet 2023; 60:866-873. [PMID: 36977548 DOI: 10.1136/jmg-2022-109018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/18/2023] [Indexed: 03/30/2023]
Abstract
BACKGROUND Titin truncating variants (TTNtvs) have been associated with several forms of myopathies and/or cardiomyopathies. In homozygosity or in compound heterozygosity, they cause a wide spectrum of recessive phenotypes with a congenital or childhood onset. Most recessive phenotypes showing a congenital or childhood onset have been described in subjects carrying biallelic TTNtv in specific exons. Often karyotype or chromosomal microarray analyses are the only tests performed when prenatal anomalies are identified. Thereby, many cases caused by TTN defects might be missed in the diagnostic evaluations. In this study, we aimed to dissect the most severe end of the titinopathies spectrum. METHODS We performed a retrospective study analysing an international cohort of 93 published and 10 unpublished cases carrying biallelic TTNtv. RESULTS We identified recurrent clinical features showing a significant correlation with the genotype, including fetal akinesia (up to 62%), arthrogryposis (up to 85%), facial dysmorphisms (up to 73%), joint (up to 17%), bone (up to 22%) and heart anomalies (up to 27%) resembling complex, syndromic phenotypes. CONCLUSION We suggest TTN to be carefully evaluated in any diagnostic process involving patients with these prenatal signs. This step will be essential to improve diagnostic performance, expand our knowledge and optimise prenatal genetic counselling.
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Affiliation(s)
- Maria Francesca Di Feo
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health (DINOGMI), University of Genoa, Genova, Italy
| | - Victoria Lillback
- Folkhälsan Research Center, Helsinki, Uusimaa, Finland
- University of Helsinki Department of Medical and Clinical Genetics, Helsinki, Uusimaa, Finland
| | - Manu Jokela
- Tampere University Hospital, Tampere, Pirkanmaa, Finland
- TYKS Turku University Hospital, Turku, Varsinais-Suomi, Finland
| | - Meriel McEntagart
- Department of Medical Genetics, St George's University of London, London, London, UK
| | - Tessa Homfray
- St George's University of London, London, London, UK
| | - Elisa Giorgio
- Department of Molecular Medicine, University of Pavia, Pavia, Lombardia, Italy
- Fondazione Istituto Neurologico Nazionale C Mondino Istituto di Ricovero e Cura a Carattere Scientifico, Pavia, Lombardia, Italy
| | - Guido C Casalis Cavalchini
- Medical Genetics Unit, Azienda Ospedaliero Universitaria Città della Salute e della Scienza di Torino, Torino, Piemonte, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Turin School of Medicine, Torino, Piemonte, Italy
| | - Maria Iascone
- Laboratorio di Genetica Medica, ASST Papa Giovanni XXIII, Bergamo, BG, Italy
| | - Luigina Spaccini
- Unità di Genetica Medica, UOC Ostetricia e Ginecologia, Ospedale dei Bambini Vittore Buzzi, Milano, Lombardia, Italy
| | - Patrizia D'Oria
- UOC Ostetrica e Ginecologia, Ospedale Bolognini di Seriate, Seriate, Lombardia, Italy
| | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Uusimaa, Finland
- Department of Medical Genetics, University of Helsinki, Helsinki, Uusimaa, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Uusimaa, Finland
- Tampere University Hospital Department of Musculoskeletal Diseases, Tampere, Pirkanmaa, Finland
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19
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Alawneh I, Yuki KE, Amburgey K, Yoon G, Dowling JJ, Hazrati LN, Gonorazky H. Titin related myopathy with ophthalmoplegia. A novel phenotype. Neuromuscul Disord 2023; 33:605-609. [PMID: 37393749 DOI: 10.1016/j.nmd.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 05/01/2023] [Accepted: 05/11/2023] [Indexed: 07/04/2023]
Abstract
Titin-related myopathy is an emerging genetic neuromuscular disorder with a wide spectrum of clinical phenotypes. To date, there have not been reports of patients with this disease that presented with extraocular muscle involvement. Here we discuss a 19-year-old male with congenital weakness, complete ophthalmoplegia, thoracolumbar scoliosis, and obstructive sleep apnea. Muscle magnetic resonance imaging revealed severe involvement of the gluteal and anterior compartment muscles, and clear adductor sparing, while muscle biopsy of the right vastus lateralis showed distinctive cap-like structures. Trio Whole Exome Sequencing (WES) showed compound heterozygous likely pathologic variants in the TTN gene. (c.82541_82544dup (p.Arg27515Serfs*2) in exon 327 (NM_001267550.2) and c.31846+1G>A (p.?) in exon 123 (NM_001267550.2). To our knowledge, this is the first report of a TTN-related disorder associated with ophthalmoplegia.
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Affiliation(s)
- Issa Alawneh
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Kyoko E Yuki
- Division of Genome Diagnostics, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Kimberly Amburgey
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Division of Genome Diagnostics, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Grace Yoon
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Division of Genetic, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - James J Dowling
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Division of Genetic, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Program of Genetic and Genome Biology, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Lili-Naz Hazrati
- Division of Pathology, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Hernan Gonorazky
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Program of Genetic and Genome Biology, The Hospital for Sick Children, University of Toronto, Toronto, Canada.
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20
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Koslow M, Mondaca-Ruff D, Xu X. Transcriptome studies of inherited dilated cardiomyopathies. Mamm Genome 2023; 34:312-322. [PMID: 36749382 PMCID: PMC10426000 DOI: 10.1007/s00335-023-09978-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: 07/25/2022] [Accepted: 01/16/2023] [Indexed: 02/08/2023]
Abstract
Dilated cardiomyopathy (DCM) is a group of heart muscle diseases that often lead to heart failure, with more than 50 causative genes have being linked to DCM. The heterogenous nature of the inherited DCMs suggest the need of precision medicine. Consistent with this emerging concept, transcriptome studies in human patients with DCM indicated distinct molecular signature for DCMs of different genetic etiology. To facilitate this line of research, we reviewed the status of transcriptome studies of inherited DCMs by focusing on three predominant DCM causative genes, TTN, LMNA, and BAG3. Besides studies in human patients, we summarized transcriptomic analysis of these inherited DCMs in a variety of model systems ranging from iPSCs to rodents and zebrafish. We concluded that the RNA-seq technology is a powerful genomic tool that has already led to the discovery of new modifying genes, signaling pathways, and related therapeutic avenues. We also pointed out that both temporal (different pathological stages) and spatial (different cell types) information need to be considered for future transcriptome studies. While an important bottle neck is the low throughput in experimentally testing differentially expressed genes, new technologies in efficient animal models such as zebrafish starts to be developed. It is anticipated that the RNA-seq technology will continue to uncover both unique and common pathological events, aiding the development of precision medicine for inherited DCMs.
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Affiliation(s)
- Matthew Koslow
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - David Mondaca-Ruff
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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21
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Linke WA. Stretching the story of titin and muscle function. J Biomech 2023; 152:111553. [PMID: 36989971 DOI: 10.1016/j.jbiomech.2023.111553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/29/2023]
Abstract
The discovery of the giant protein titin, also known as connectin, dates almost half a century back. In this review, I recapitulate major advances in the discovery of the titin filaments and the recognition of their properties and function until today. I briefly discuss how our understanding of the layout and interactions of titin in muscle sarcomeres has evolved and review key facts about the titin sequence at the gene (TTN) and protein levels. I also touch upon properties of titin important for the stability of the contractile units and the assembly and maintenance of sarcomeric proteins. The greater part of my discussion centers around the mechanical function of titin in skeletal muscle. I cover milestones of research on titin's role in stretch-dependent passive tension development, recollect the reasons behind the enormous elastic diversity of titin, and provide an update on the molecular mechanisms of titin elasticity, details of which are emerging even now. I reflect on current knowledge of how muscle fibers behave mechanically if titin stiffness is removed and how titin stiffness can be dynamically regulated, such as by posttranslational modifications or calcium binding. Finally, I highlight novel and exciting, but still controversially discussed, insight into the role titin plays in active tension development, such as length-dependent activation and contraction from longer muscle lengths.
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Affiliation(s)
- Wolfgang A Linke
- Institute of Physiology II, University of Münster, Germany; Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Germany; German Centre for Cardiovascular Research, Berlin, Germany.
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22
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Grogan A, Huang W, Brong A, Kane MA, Kontrogianni-Konstantopoulos A. Alterations in cytoskeletal and Ca 2+ cycling regulators in atria lacking the obscurin Ig58/59 module. Front Cardiovasc Med 2023; 10:1085840. [PMID: 37304957 PMCID: PMC10251194 DOI: 10.3389/fcvm.2023.1085840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/26/2023] [Indexed: 06/13/2023] Open
Abstract
Introduction Obscurin (720-870 kDa) is a giant cytoskeletal and signaling protein that possesses both structural and regulatory functions in striated muscles. Immunoglobulin domains 58/59 (Ig58/59) of obscurin bind to a diverse set of proteins that are essential for the proper structure and function of the heart, including giant titin, novex-3, and phospholamban (PLN). Importantly, the pathophysiological significance of the Ig58/59 module has been further underscored by the discovery of several mutations within Ig58/59 that are linked to various forms of myopathy in humans. We previously generated a constitutive deletion mouse model, Obscn-ΔIg58/59, that expresses obscurin lacking Ig58/59, and characterized the effects of this deletion on cardiac morphology and function through aging. Our findings demonstrated that Obscn-ΔIg58/59 male animals develop severe arrhythmia, primarily manifesting as episodes of junctional escape and spontaneous loss of regular p-waves, reminiscent of human atrial fibrillation, accompanied by significant atrial enlargement that progresses in severity with aging. Methods and Results To comprehensively characterize the molecular alterations responsible for these pathologies, we performed proteomic and phospho-proteomic analyses in aging Obscn-ΔIg58/59 atria. Our studies revealed extensive and novel alterations in the expression and phosphorylation profile of major cytoskeletal proteins, Ca2+ regulators, and Z-disk associated protein complexes in the Obscn-ΔIg58/59 atria through aging. Discussion These studies implicate obscurin, particularly the Ig58/59 module, as an essential regulator of the Z-disk associated cytoskeleton and Ca2+ cycling in the atria and provide new molecular insights into the development of atrial fibrillation and remodeling.
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Affiliation(s)
- Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, United States
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, United States
| | - Annie Brong
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, United States
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, United States
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23
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Montañés-Agudo P, Pinto YM, Creemers EE. Splicing factors in the heart: Uncovering shared and unique targets. J Mol Cell Cardiol 2023; 179:72-79. [PMID: 37059416 DOI: 10.1016/j.yjmcc.2023.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/29/2023] [Accepted: 04/09/2023] [Indexed: 04/16/2023]
Abstract
Alternative splicing generates specialized protein isoforms that allow the heart to adapt during development and disease. The recent discovery that mutations in the splicing factor RNA-binding protein 20 (RBM20) cause a severe form of familial dilated cardiomyopathy has sparked a great interest in alternative splicing in the field of cardiology. Since then, identification of splicing factors controlling alternative splicing in the heart has grown at a rapid pace. Despite the intriguing observation that a certain overlap exists between the targets of some splicing factors, an integrated and systematic analysis of their splicing networks is missing. Here, we compared the splicing networks of individual splicing factors by re-analyzing original RNA-sequencing data from eight previously published mouse models, in which a single splicing factor has been genetically deleted (i.e. HNRNPU, MBNL1/2, QKI, RBM20, RBM24, RBPMS, SRSF3, SRSF4). We show that key splicing events in Camk2d, Ryr2, Tpm1, Tpm2 and Pdlim5 require the combined action of the majority of these splicing factors. Additionally, we identified common targets and pathways among splicing factors, with the largest overlap between the splicing networks of MBNL, QKI and RBM24. We also re-analyzed a large-scale RNA-sequencing study on hearts of 128 heart failure patients. Here, we observed that MBNL1, QKI and RBM24 expression varied greatly. This variation in expression correlated with differential splicing of their downstream targets as found in mice, suggesting that aberrant splicing by MBNL1, QKI and RBM24 might contribute to the disease mechanism in heart failure.
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Affiliation(s)
- Pablo Montañés-Agudo
- Experimental Cardiology, Room K2-112, Amsterdam UMC Location University of Amsterdam, Meibergdreef 15, Amsterdam 1105AZ, the Netherlands.
| | - Yigal M Pinto
- Experimental Cardiology, Room K2-104, Amsterdam UMC, location University of Amsterdam, Meibergdreef 15, Amsterdam 1105AZ, the Netherlands.
| | - Esther E Creemers
- Experimental Cardiology, Room K2-104-2, Amsterdam UMC, Location University of Amsterdam, Meibergdreef 15, Amsterdam 1105AZ, the Netherlands.
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24
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Mauriello GE, Moncure GE, Nowzari RA, Miller CJ, Wright NT. The N-terminus of obscurin is flexible in solution. Proteins 2023; 91:485-496. [PMID: 36306263 DOI: 10.1002/prot.26442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/13/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
The N-terminal half of the giant cytoskeletal protein obscurin is comprised of more than 50 Ig-like domains, arranged in tandem. Domains 18-51 are connected to each other through short 5-residue linkers, and this arrangement has been previously shown to form a semi-flexible rod in solution. Domains 1-18 generally have slightly longer ~7 residue interdomain linkers, and the multidomain structure and motion conferred by this kind of linker is understudied. Here, we use NMR, SAXS, and MD to show that these longer linkers are associated with significantly more domain/domain flexibility, with the resulting multidomain structure being moderately compact. Further examination of the relationship between interdomain flexibility and linker length shows there is a 5 residue "sweet spot" linker length that results in dual-domain systems being extended, and conversely that both longer or shorter linkers result in a less extended structure. This detailed knowledge of the obscurin N terminus structure and flexibility allowed for mathematical modeling of domains 1-18, which suggests that this region likely forms tangles if left alone in solution. Given how infrequently protein tangles occur in nature, and given the pathological outcomes that occur when tangles do arise, our data suggest that obscurin is likely either significantly scaffolded or else externally extended in the cell.
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Affiliation(s)
- Gianna E Mauriello
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, USA
| | - Grace E Moncure
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, USA
| | - Roujon A Nowzari
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, USA
| | - Callie J Miller
- Department of Engineering, James Madison University, Harrisonburg, Virginia, USA
| | - Nathan T Wright
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, USA
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25
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Eccentric muscle contractions: from single muscle fibre to whole muscle mechanics. Pflugers Arch 2023; 475:421-435. [PMID: 36790515 PMCID: PMC10011336 DOI: 10.1007/s00424-023-02794-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/24/2023] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
Eccentric muscle loading encompasses several unique features compared to other types of contractions. These features include increased force, work, and performance at decreased oxygen consumption, reduced metabolic cost, improved energy efficiency, as well as decreased muscle activity. This review summarises explanatory approaches to long-standing questions in terms of muscular contraction dynamics and molecular and cellular mechanisms underlying eccentric muscle loading. Moreover, this article intends to underscore the functional link between sarcomeric components, emphasising the fundamental role of titin in skeletal muscle. The giant filament titin reveals versatile functions ranging from sarcomere organisation and maintenance, providing passive tension and elasticity, and operates as a mechanosensory and signalling platform. Structurally, titin consists of a viscoelastic spring segment that allows activation-dependent coupling to actin. This titin-actin interaction can explain linear force increases in active lengthening experiments in biological systems. A three-filament model of skeletal muscle force production (mediated by titin) is supposed to overcome significant deviations between experimental observations and predictions by the classic sliding-filament and cross-bridge theories. Taken together, this review intends to contribute to a more detailed understanding of overall muscle behaviour and force generation-from a microscopic sarcomere level to a macroscopic multi-joint muscle level-impacting muscle modelling, the understanding of muscle function, and disease.
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26
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Cardone N, Moula M, Baelde RJ, Biquand A, Villanova M, Metay C, Fiorillo C, Baratto S, Merlini L, Sabatelli P, Romero NB, Relaix F, Authier FJ, Taglietti V, Savarese M, de Winter J, Ottenheijm C, Richard I, Malfatti E. Clinical and functional characterization of a long survivor congenital titinopathy patient with a novel metatranscript-only titin variant. Acta Neuropathol Commun 2023; 11:48. [PMID: 36945066 PMCID: PMC10031982 DOI: 10.1186/s40478-023-01539-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/03/2023] [Indexed: 03/23/2023] Open
Abstract
Congenital titinopathies are an emerging group of a potentially severe form of congenital myopathies caused by biallelic mutations in titin, encoding the largest existing human protein involved in the formation and stability of sarcomeres. In this study we describe a patient with a congenital myopathy characterized by multiple contractures, a rigid spine, non progressive muscular weakness, and a novel homozygous TTN pathogenic variant in a metatranscript-only exon: the c.36400A > T, p.Lys12134*. Muscle biopsies showed increased internalized nuclei, variability in fiber size, mild fibrosis, type 1 fiber predominance, and a slight increase in the number of satellite cells. RNA studies revealed the retention of intron 170 and 171 in the open reading frame, and immunoflourescence and western blot studies, a normal titin content. Single fiber functional studies showed a slight decrease in absolute maximal force and a cross-sectional area with no decreases in tension, suggesting that weakness is not sarcomere-based but due to hypotrophy. Passive properties of single fibers were not affected, but the observed increased calcium sensitivity of force generation might contribute to the contractural phenotype and rigid spine of the patient. Our findings provide evidence for a pathogenic, causative role of a metatranscript-only titin variant in a long survivor congenital titinopathy patient with distal arthrogryposis and rigid spine.
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Affiliation(s)
- Nastasia Cardone
- Univ Paris-Est Créteil, INSERM, U955 IMRB, F-94010, Créteil, France
| | - Melissa Moula
- Univ Paris-Est Créteil, INSERM, U955 IMRB, F-94010, Créteil, France
| | - Rianne J Baelde
- Amsterdam UMC location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1117, Amsterdam, Netherlands
| | | | - Marcello Villanova
- Neuromuscular Unit, Presidio Ospedaliero Accreditato Villa Bellombra, Bologna, Italy
| | - Corinne Metay
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire. Centre de Génétique Moléculaire et Chromosomique et INSERM UMRS 974, Institut de Myologie. Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, INSERM UMRS1166, Sorbonne Université, Paris, France
| | - Chiara Fiorillo
- Neurologia Pediatrica e Malattie Muscolari, Istituto G.Gaslini, Genoa, Italy
| | - Serena Baratto
- Neurologia Pediatrica e Malattie Muscolari, Istituto G.Gaslini, Genoa, Italy
| | - Luciano Merlini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126, Bologna, Italy
| | - Patrizia Sabatelli
- CNR, Institute of Molecular Genetics "Luigi Luca Cavalli Sforza" -Unit of Bologna, Bologna, Italy
- IRCCS-Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Norma B Romero
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
| | - Frederic Relaix
- Univ Paris-Est Créteil, INSERM, U955 IMRB, F-94010, Créteil, France
| | - François Jérôme Authier
- Univ Paris-Est Créteil, INSERM, U955 IMRB, F-94010, Créteil, France
- APHP, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor Hospital, Créteil, France
| | | | | | - Josine de Winter
- Amsterdam UMC location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1117, Amsterdam, Netherlands
| | - Coen Ottenheijm
- Amsterdam UMC location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1117, Amsterdam, Netherlands
| | | | - Edoardo Malfatti
- Univ Paris-Est Créteil, INSERM, U955 IMRB, F-94010, Créteil, France.
- APHP, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor Hospital, Créteil, France.
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27
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Parker F, Tang AAS, Rogers B, Carrington G, dos Remedios C, Li A, Tomlinson D, Peckham M. Affimers targeting proteins in the cardiomyocyte Z-disc: Novel tools that improve imaging of heart tissue. Front Cardiovasc Med 2023; 10:1094563. [PMID: 36865889 PMCID: PMC9971620 DOI: 10.3389/fcvm.2023.1094563] [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: 11/10/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Dilated Cardiomyopathy is a common form of heart failure. Determining how this disease affects the structure and organization of cardiomyocytes in the human heart is important in understanding how the heart becomes less effective at contraction. Here we isolated and characterised Affimers (small non-antibody binding proteins) to Z-disc proteins ACTN2 (α-actinin-2), ZASP (also known as LIM domain binding protein 3 or LDB3) and the N-terminal region of the giant protein titin (TTN Z1-Z2). These proteins are known to localise in both the sarcomere Z-discs and the transitional junctions, found close to the intercalated discs that connect adjacent cardiomyocytes. We use cryosections of left ventricles from two patients diagnosed with end-stage Dilated Cardiomyopathy who underwent Orthotopic Heart Transplantation and were whole genome sequenced. We describe how Affimers substantially improve the resolution achieved by confocal and STED microscopy compared to conventional antibodies. We quantified the expression of ACTN2, ZASP and TTN proteins in two patients with dilated cardiomyopathy and compared them with a sex- and age-matched healthy donor. The small size of the Affimer reagents, combined with a small linkage error (the distance from the epitope to the dye label covalently bound to the Affimer) revealed new structural details in Z-discs and intercalated discs in the failing samples. Affimers are thus useful for analysis of changes to cardiomyocyte structure and organisation in diseased hearts.
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Affiliation(s)
- Francine Parker
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Anna A. S. Tang
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Brendan Rogers
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Glenn Carrington
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Cris dos Remedios
- Mechanobiology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Amy Li
- Sydney Heart Bank, The University of Sydney, Sydney, NSW, Australia
- Department of Pharmacy & Biomedical Sciences, La Trobe University, Bendigo, VIC, Australia
- Centre for Healthy Futures, Torrens University Australia, Surrey Hills, NSW, Australia
| | - Darren Tomlinson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Michelle Peckham
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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28
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Stergiou C, Williams R, Fleming JR, Zouvelou V, Ninou E, Andreetta F, Rinaldi E, Simoncini O, Mantegazza R, Bogomolovas J, Tzartos J, Labeit S, Mayans O, Tzartos S. Immunological and Structural Characterization of Titin Main Immunogenic Region; I110 Domain Is the Target of Titin Antibodies in Myasthenia Gravis. Biomedicines 2023; 11:biomedicines11020449. [PMID: 36830985 PMCID: PMC9952892 DOI: 10.3390/biomedicines11020449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/08/2023] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies targeting the neuromuscular junction (NJ) of skeletal muscles. The major MG autoantigen is nicotinic acetylcholine receptor. Other autoantigens at the NJ include MuSK, LRP4 and agrin. Autoantibodies to the intra-sarcomeric striated muscle-specific gigantic protein titin, although not directed to the NJ, are invaluable biomarkers for thymoma and MG disease severity. Thymus and thymoma are critical in MG mechanisms and management. Titin autoantibodies bind to a 30 KDa titin segment, the main immunogenic region (MIR), consisting of an Ig-FnIII-FnIII 3-domain tandem, termed I109-I111. In this work, we further resolved the localization of titin epitope(s) to facilitate the development of more specific anti-titin diagnostics. For this, we expressed protein samples corresponding to 8 MIR and non-MIR titin fragments and tested 77 anti-titin sera for antibody binding using ELISA, competition experiments and Western blots. All anti-MIR antibodies were bound exclusively to the central MIR domain, I110, and to its containing titin segments. Most antibodies were bound also to SDS-denatured I110 on Western blots, suggesting that their epitope(s) are non-conformational. No significant difference was observed between thymoma and non-thymoma patients or between early- and late-onset MG. In addition, atomic 3D-structures of the MIR and its subcomponents were elucidated using X-ray crystallography. These immunological and structural data will allow further studies into the atomic determinants underlying titin-based autoimmunity, improved diagnostics and how to eventually treat titin autoimmunity associated co-morbidities.
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Affiliation(s)
| | - Rhys Williams
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | | | - Vasiliki Zouvelou
- 1st Neurology Department, Eginition Hospital, National and Kapodistrian University of Athens, 157 72 Athens, Greece
| | | | - Francesca Andreetta
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Elena Rinaldi
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Ornella Simoncini
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Renato Mantegazza
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Julius Bogomolovas
- School of Medicine, University of California, La Jolla, San Diego, CA 92093, USA
| | - John Tzartos
- School of Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, 124 62 Athens, Greece
| | - Siegfried Labeit
- DZHK Partner Site Mannheim-Heidelberg, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
- Myomedix GmbH, 69151 Neckargemuend, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Socrates Tzartos
- Tzartos NeuroDiagnostics, 115 23 Athens, Greece
- Hellenic Pasteur Institute, 115 21 Athens, Greece
- Department of Pharmacy, University of Patras, 265 00 Patras, Greece
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29
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Golding GB, Koponen H, Mhaskar N, Smyth WF. Computing Maximal Covers for Protein Sequences. J Comput Biol 2023; 30:149-160. [PMID: 35939266 DOI: 10.1089/cmb.2021.0520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A partial cover of a string or sequence of length n, which we model as an array x=x[1..n], is a repeating substring u of x such that "many" positions in x lie within occurrences of u. A maximal cover u*-introduced in 2018 by Mhaskar and Smyth as optimal cover-is a partial cover that, over all partial covers u, maximizes the positions covered. Applying data structures also introduced by Mhaskar and Smyth, our software MAXCOVER for the first time enables efficient computation of u* for any x-in particular, as described here, for protein sequences of Arabidopsis, Caenorhabditis elegans, Drosophila melanogaster, and humans. In this protein context, we also compare an extended version of MAXCOVER with existing software (MUMmer's repeat-match) for the closely related task of computing non-extendible repeating substrings (a.k.a. maximal repeats). In practice, MAXCOVER is an order-of-magnitude faster than MUMmer, with much lower space requirements, while producing more compact output that, nevertheless, yields a more exact and user-friendly specification of the repeats.
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Affiliation(s)
- G Brian Golding
- Department of Biology, and McMaster University, Hamilton, Ontario, Canada
| | - Holly Koponen
- Department of Computing and Software, McMaster University, Hamilton, Ontario, Canada
| | - Neerja Mhaskar
- Department of Computing and Software, McMaster University, Hamilton, Ontario, Canada
| | - W F Smyth
- Department of Computing and Software, McMaster University, Hamilton, Ontario, Canada
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30
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Qi Y, Ji X, Ding H, Wang Y, Liu X, Zhang Y, Yin A. A spectrum of clinical severity of recessive titinopathies in prenatal. Front Genet 2023; 13:1064474. [PMID: 36761691 PMCID: PMC9907677 DOI: 10.3389/fgene.2022.1064474] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/23/2022] [Indexed: 01/26/2023] Open
Abstract
Variants in TTN are associated with a broad range of clinical phenotypes, from dominant adult-onset dilated cardiomyopathy to recessive infantile-onset myopathy. However, few foetal cases have been reported for multiple reasons. Next-generation sequencing has facilitated the prenatal identification of a growing number of suspected titinopathy variants. We investigated six affected foetuses from three families, completed the intrauterine course of the serial phenotypic spectrum of TTN, and discussed the genotype-phenotype correlations from a broader perspective. The recognizable prenatal feature onset at the second trimester was started with reduced movement, then contracture 3-6 weeks later, followed with/without hydrops, finally at late pregnancy was accompanied with polyhydramnio (major) or oligohydramnios. Two cases with typical arthrogryposis-hydrops sequences identified a meta-only transcript variant c.36203-1G>T. Deleterious transcriptional consequences of the substitution were verified by minigene splicing analysis. Case 3 identified a homozygous splicing variant in the constitutively expressed Z-disc. It presented a milder phenotype than expected, which was presumably saved by the isoform of corons. A summary of the foetal-onset titinopathy cases implied that variants in TTN present with a series of signs and a spectrum of clinical severity, which followed the dosage/positional effect; the meta-only transcript allele involvement may be a prerequisite for the development of fatal hydrops.
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Affiliation(s)
- Yiming Qi
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Xueqi Ji
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Guangzhou Medical University, Guangzhou, China
| | - Hongke Ding
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Yunan Wang
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | | | - Yan Zhang
- Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Aihua Yin
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China,*Correspondence: Aihua Yin,
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31
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Noureddine M, Gehmlich K. Structural and signaling proteins in the Z-disk and their role in cardiomyopathies. Front Physiol 2023; 14:1143858. [PMID: 36935760 PMCID: PMC10017460 DOI: 10.3389/fphys.2023.1143858] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The sarcomere is the smallest functional unit of muscle contraction. It is delineated by a protein-rich structure known as the Z-disk, alternating with M-bands. The Z-disk anchors the actin-rich thin filaments and plays a crucial role in maintaining the mechanical stability of the cardiac muscle. A multitude of proteins interact with each other at the Z-disk and they regulate the mechanical properties of the thin filaments. Over the past 2 decades, the role of the Z-disk in cardiac muscle contraction has been assessed widely, however, the impact of genetic variants in Z-disk proteins has still not been fully elucidated. This review discusses the various Z-disk proteins (alpha-actinin, filamin C, titin, muscle LIM protein, telethonin, myopalladin, nebulette, and nexilin) and Z-disk-associated proteins (desmin, and obscurin) and their role in cardiac structural stability and intracellular signaling. This review further explores how genetic variants of Z-disk proteins are linked to inherited cardiac conditions termed cardiomyopathies.
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Affiliation(s)
- Maya Noureddine
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Maya Noureddine, ; Katja Gehmlich,
| | - Katja Gehmlich
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, United Kingdom
- *Correspondence: Maya Noureddine, ; Katja Gehmlich,
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McCord M, Bartom E, Burdett K, Baran A, Eckerdt FD, Balyasnikova IV, McCortney K, Sears T, Cheng SY, Sarkaria JN, Stupp R, Heimberger AB, Ahmed A, James CD, Horbinski C. Modeling Therapy-Driven Evolution of Glioblastoma with Patient-Derived Xenografts. Cancers (Basel) 2022; 14:5494. [PMID: 36428586 PMCID: PMC9688760 DOI: 10.3390/cancers14225494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 11/12/2022] Open
Abstract
Adult-type diffusely infiltrating gliomas, of which glioblastoma is the most common and aggressive, almost always recur after treatment and are fatal. Improved understanding of therapy-driven tumor evolution and acquired therapy resistance in gliomas is essential for improving patient outcomes, yet the majority of the models currently used in preclinical research are of therapy-naïve tumors. Here, we describe the development of therapy-resistant IDH-wildtype glioblastoma patient-derived xenografts (PDX) through orthotopic engraftment of therapy naïve PDX in athymic nude mice, and repeated in vivo exposure to the therapeutic modalities most often used in treating glioblastoma patients: radiotherapy and temozolomide chemotherapy. Post-temozolomide PDX became enriched for C>T transition mutations, acquired inactivating mutations in DNA mismatch repair genes (especially MSH6), and developed hypermutation. Such post-temozolomide PDX were resistant to additional temozolomide (median survival decrease from 80 days in parental PDX to 42 days in a temozolomide-resistant derivative). However, temozolomide-resistant PDX were sensitive to lomustine (also known as CCNU), a nitrosourea which induces tumor cell apoptosis by a different mechanism than temozolomide. These PDX models mimic changes observed in recurrent GBM in patients, including critical features of therapy-driven tumor evolution. These models can therefore serve as valuable tools for improving our understanding and treatment of recurrent glioma.
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Affiliation(s)
- Matthew McCord
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Elizabeth Bartom
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kirsten Burdett
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Aneta Baran
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Frank D. Eckerdt
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Irina V. Balyasnikova
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kathleen McCortney
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Thomas Sears
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Shi-Yuan Cheng
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jann N. Sarkaria
- Department of Radiation Oncology, Mayo Clinic, Rochester Minnesota, Rochester, MN 55905, USA
| | - Roger Stupp
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Amy B. Heimberger
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Atique Ahmed
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Charles David James
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Craig Horbinski
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Lou and Jean Malnati Brain Tumor Institute of Northwestern Medicine, Chicago, IL 60611, USA
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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Usui Y, Kimoto M, Hanashima A, Hashimoto K, Mohri S. Cardiac hemodynamics and ventricular stiffness of sea-run cherry salmon (Oncorhynchus masou masou) differ critically from those of landlocked masu salmon. PLoS One 2022; 17:e0267264. [PMID: 36331913 PMCID: PMC9635730 DOI: 10.1371/journal.pone.0267264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Ventricular diastolic mechanical properties are important determinants of cardiac function and are optimized by changes in cardiac structure and physical properties. Oncorhynchus masou masou is an anadromous migratory fish of the Salmonidae family, and several ecological studies on it have been conducted; however, the cardiac functions of the fish are not well known. Therefore, we investigated ventricular diastolic function in landlocked (masu salmon) and sea-run (cherry salmon) types at 29–30 months post fertilization. Pulsed-wave Doppler echocardiography showed that the atrioventricular inflow waveforms of cherry salmon were biphasic with early diastolic filling and atrial contraction, whereas those of masu salmon were monophasic with atrial contraction. In addition, end-diastolic pressure–volume relationship analysis revealed that the dilatability per unit myocardial mass of the ventricle in cherry salmon was significantly suppressed compared to that in masu salmon, suggesting that the ventricle of the cherry salmon was relatively stiffer (relative ventricular stiffness index; p = 0.0263). Contrastingly, the extensibility of cardiomyocytes, characterized by the expression pattern of Connectin isoforms in their ventricles, was similar in both types. Histological analysis showed that the percentage of the collagen accumulation area in the compact layer of cherry salmon increased compared with that of the masu salmon, which may contribute to ventricle stiffness. Although the heart mass of cherry salmon was about 11-fold greater than that of masu salmon, there was no difference in the morphology of the isolated cardiomyocytes, suggesting that the heart of the cherry salmon grows by cardiomyocyte proliferation, but not cell hypertrophy. The cardiac physiological function of the teleosts varies with differences in their developmental processes and life history. Our multidimensional analysis of the O. masou heart may provide a clue to the process by which the heart acquires a biphasic blood-filling pattern, i.e., a ventricular diastolic suction.
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Affiliation(s)
- Yuu Usui
- First Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
- * E-mail:
| | - Misaki Kimoto
- First Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Akira Hanashima
- First Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Ken Hashimoto
- First Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Satoshi Mohri
- First Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
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Ford MKB, Hari A, Rodriguez O, Xu J, Lack J, Oguz C, Zhang Y, Weber S, Magliocco M, Barnett J, Xirasagar S, Samuel S, Imberti L, Bonfanti P, Biondi A, Dalgard CL, Chanock S, Rosen L, Holland S, Su H, Notarangelo L, Vishkin U, Watson CT, Sahinalp SC. ImmunoTyper-SR: A computational approach for genotyping immunoglobulin heavy chain variable genes using short-read data. Cell Syst 2022; 13:808-816.e5. [PMID: 36265467 PMCID: PMC10084889 DOI: 10.1016/j.cels.2022.08.008] [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: 04/01/2022] [Revised: 07/20/2022] [Accepted: 08/22/2022] [Indexed: 01/26/2023]
Abstract
Human immunoglobulin heavy chain (IGH) locus on chromosome 14 includes more than 40 functional copies of the variable gene (IGHV), which are critical for the structure of antibodies that identify and neutralize pathogenic invaders as a part of the adaptive immune system. Because of its highly repetitive sequence composition, the IGH locus has been particularly difficult to assemble or genotype when using standard short-read sequencing technologies. Here, we introduce ImmunoTyper-SR, an algorithmic tool for the genotyping and CNV analysis of the germline IGHV genes on Illumina whole-genome sequencing (WGS) data using a combinatorial optimization formulation that resolves ambiguous read mappings. We have validated ImmunoTyper-SR on 12 individuals, whose IGHV allele composition had been independently validated, as well as concordance between WGS replicates from nine individuals. We then applied ImmunoTyper-SR on 585 COVID patients to investigate the associations between IGHV alleles and anti-type I IFN autoantibodies, which were previously associated with COVID-19 severity.
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Affiliation(s)
| | - Ananth Hari
- National Cancer Institute, NIH, Bethesda, MD, USA; Department of Electrical Engineering, University of Maryland, College Park, MD, USA
| | - Oscar Rodriguez
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY, USA
| | - Junyan Xu
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Justin Lack
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Cihan Oguz
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Yu Zhang
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Sarah Weber
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Mary Magliocco
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Jason Barnett
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Sandhya Xirasagar
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Smilee Samuel
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Luisa Imberti
- Diagnostic Department, ASST Spedali Civili di Brescia, Brescia, Italy
| | - Paolo Bonfanti
- University of Milano-Bicocca, Fondazione MBBM, Monza, Italy
| | - Andrea Biondi
- University of Milano-Bicocca, Fondazione MBBM, Monza, Italy
| | - Clifton L Dalgard
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | | | - Lindsey Rosen
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Steven Holland
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Helen Su
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Luigi Notarangelo
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Uzi Vishkin
- Department of Electrical Engineering, University of Maryland, College Park, MD, USA
| | - Corey T Watson
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY, USA
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Bayega A, Oikonomopoulos S, Wang YC, Ragoussis J. Improved Nanopore full-length cDNA sequencing by PCR-suppression. Front Genet 2022; 13:1031355. [PMID: 36324505 PMCID: PMC9618600 DOI: 10.3389/fgene.2022.1031355] [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: 08/29/2022] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
Full-length transcript sequencing remains a main goal of RNA sequencing. However, even the application of long-read sequencing technologies such as Oxford Nanopore Technologies still fail to yield full-length transcript sequencing for a significant portion of sequenced reads. Since these technologies can sequence reads that are far longer than the longest known processed transcripts, the lack of efficiency to obtain full-length transcripts from good quality RNAs stems from library preparation inefficiency rather than the presence of degraded RNA molecules. It has previously been shown that addition of inverted terminal repeats in cDNA during reverse transcription followed by single-primer PCR creates a PCR suppression effect that prevents amplification of short molecules thus enriching the library for longer transcripts. We adapted this method for Nanopore cDNA library preparation and show that not only is PCR efficiency increased but gene body coverage is dramatically improved. The results show that implementation of this simple strategy will result in better quality full-length RNA sequencing data and make full-length transcript sequencing possible for most of sequenced reads.
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Affiliation(s)
- Anthony Bayega
- Department of Human Genetics, McGill University Genome Centre, McGill University, Montréal, QC, Canada
| | - Spyros Oikonomopoulos
- Department of Human Genetics, McGill University Genome Centre, McGill University, Montréal, QC, Canada
| | - Yu Chang Wang
- Department of Human Genetics, McGill University Genome Centre, McGill University, Montréal, QC, Canada
| | - Jiannis Ragoussis
- Department of Human Genetics, McGill University Genome Centre, McGill University, Montréal, QC, Canada
- Department of Bioengineering, McGill University, Montréal, QC, Canada
- *Correspondence: Jiannis Ragoussis,
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36
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Hettige P, Tahir U, Nishikawa KC, Gage MJ. Transcriptomic profiles of muscular dystrophy with myositis (mdm) in extensor digitorum longus, psoas, and soleus muscles from mice. BMC Genomics 2022; 23:657. [PMID: 36115951 PMCID: PMC9482285 DOI: 10.1186/s12864-022-08873-2] [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: 06/07/2022] [Accepted: 09/02/2022] [Indexed: 11/11/2022] Open
Abstract
Background Titinopathies are inherited muscular diseases triggered by genetic mutations in the titin gene. Muscular dystrophy with myositis (mdm) is one such disease caused by a LINE repeat insertion, leading to exon skipping and an 83-amino acid residue deletion in the N2A-PEVK region of mouse titin. This region has been implicated in a number of titin—titin ligand interactions, hence are important for myocyte signaling and health. Mice with this mdm mutation develop a severe and progressive muscle degeneration. The range of phenotypic differences observed in mdm mice shows that the deletion of this region induces a cascade of transcriptional changes extending to numerous signaling pathways affected by the titin filament. Previous research has focused on correlating phenotypic differences with muscle function in mdm mice. These studies have provided understanding of the downstream physiological effects resulting from the mdm mutation but only provide insights on processes that can be physiologically observed and measured. We used differential gene expression (DGE) to compare the transcriptomes of extensor digitorum longus (EDL), psoas and soleus muscles from wild-type and mdm mice to develop a deeper understand of these tissue-specific responses. Results The overall expression pattern observed shows a well-differentiated transcriptional signature in mdm muscles compared to wild type. Muscle-specific clusters observed within the mdm transcriptome highlight the level of variability of each muscle to the deletion. Differential gene expression and weighted gene co-expression network analysis showed a strong directional response in oxidative respiration-associated mitochondrial genes, which aligns with the poor shivering and non-shivering thermogenesis previously observed. Sln, which is a marker associated with shivering and non-shivering thermogenesis, showed the strongest expression change in fast-fibered muscles. No drastic changes in MYH expression levels were reported, which indicated an absence of major fiber-type switching events. Overall expression shifts in MYH isoforms, MARPs, and extracellular matrix associated genes demonstrated the transcriptional complexity associated with mdm mutation. The expression alterations in mitochondrial respiration and metabolism related genes in the mdm muscle dominated over other transcriptomic changes, and likely account for the late stage cellular responses in the mdm muscles. Conclusions We were able to demonstrate that the complex nature of mdm mutation extends beyond a simple rearrangement in titin gene. EDL, psoas and soleus exemplify unique response modes observed in skeletal muscles with mdm mutation. Our data also raises the possibility that failure to maintain proper energy homeostasis in mdm muscles may contribute to the pathogenesis of the degenerative phenotype in mdm mice. Understanding the full disease-causing molecular cascade is difficult using bulk RNA sequencing techniques due to intricate nature of the disease. The development of the mdm phenotype is temporally and spatially regulated, hence future studies should focus on single fiber level investigations. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08873-2.
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Marcello M, Cetrangolo V, Savarese M, Udd B. Use of animal models to understand titin physiology and pathology. J Cell Mol Med 2022; 26:5103-5112. [PMID: 36065969 PMCID: PMC9575118 DOI: 10.1111/jcmm.17533] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/01/2022] Open
Abstract
In recent years, increasing attention has been paid to titin (TTN) and its mutations. Heterozygous TTN truncating variants (TTNtv) increase the risk of a cardiomyopathy. At the same time, TTNtv and few missense variants have been identified in patients with mainly recessive skeletal muscle diseases. The pathogenic mechanisms underlying titin‐related diseases are still partly unknown. Similarly, the titin mechanical and functional role in the muscle contraction are far from being exhaustively clarified. In the last few years, several animal models carrying variants in the titin gene have been developed and characterized to study the structural and mechanical properties of specific titin domains or to mimic patients' mutations. This review describes the main animal models so far characterized, including eight mice models and three fish models (Medaka and Zebrafish) and discusses the useful insights provided by a thorough characterization of the cell‐, tissue‐ and organism‐phenotypes in these models.
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Affiliation(s)
| | | | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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Gritsyna YV, Grabarskaya MA, Mikhailova GZ, Popova SS, Bobyleva LG, Ermakov AM, Zakharova NM, Vikhlyantsev IM. Differential Expression of Titin and Obscurin mRNA in Striated Muscles of the Long-Tailed Ground Squirrel Urocitellus undulatus. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022050052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Interdomain Linker Effect on the Mechanical Stability of Ig Domains in Titin. Int J Mol Sci 2022; 23:ijms23179836. [PMID: 36077234 PMCID: PMC9456048 DOI: 10.3390/ijms23179836] [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: 07/30/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
Titin is the largest protein in humans, composed of more than one hundred immunoglobulin (Ig) domains, and plays a critical role in muscle’s passive elasticity. Thus, the molecular design of this giant polyprotein is responsible for its mechanical function. Interestingly, most of these Ig domains are connected directly with very few interdomain residues/linker, which suggests such a design is necessary for its mechanical stability. To understand this design, we chose six representative Ig domains in titin and added nine glycine residues (9G) as an artificial interdomain linker between these Ig domains. We measured their mechanical stabilities using atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) and compared them to the natural sequence. The AFM results showed that the linker affected the mechanical stability of Ig domains. The linker mostly reduces its mechanical stability to a moderate extent, but the opposite situation can happen. Thus, this effect is very complex and may depend on each particular domain’s property.
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40
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Contributions of Titin and Collagen to Passive Stress in Muscles from mdm Mice with a Small Deletion in Titin’s Molecular Spring. Int J Mol Sci 2022; 23:ijms23168858. [PMID: 36012129 PMCID: PMC9408699 DOI: 10.3390/ijms23168858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/01/2022] [Accepted: 08/07/2022] [Indexed: 12/12/2022] Open
Abstract
Muscular dystrophy with myositis (mdm) is a naturally occurring mutation in the mouse Ttn gene that results in higher passive stress in muscle fibers and intact muscles compared to wild-type (WT). The goal of this study was to test whether alternative splicing of titin exons occurs in mdm muscles, which contain a small deletion in the N2A-PEVK regions of titin, and to test whether splicing changes are associated with an increase in titin-based passive tension. Although higher levels of collagen have been reported previously in mdm muscles, here we demonstrate alternative splicing of titin in mdm skeletal muscle fibers. We identified Z-band, PEVK, and C-terminus Mex5 exons as splicing hotspots in mdm titin using RNA sequencing data and further reported upregulation in ECM-associated genes. We also treated skinned mdm soleus fiber bundles with trypsin, trypsin + KCl, and trypsin + KCL + KI to degrade titin. The results showed that passive stress dropped significantly more after trypsin treatment in mdm fibers (11 ± 1.6 mN/mm2) than in WT fibers (4.8 ± 1 mN/mm2; p = 0.0004). The finding that treatment with trypsin reduces titin-based passive tension more in mdm than in WT fibers supports the hypothesis that exon splicing leads to the expression of a stiffer and shorter titin isoform in mdm fibers. After titin extraction by trypsin + KCl + KI, mdm fibers (6.7 ± 1.27 mN/mm2) had significantly higher collagen-based passive stress remaining than WT fibers (2.6 ± 1.3 mN/mm2; p = 0.0014). We conclude that both titin and collagen contribute to higher passive tension of mdm muscles.
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Hurley KL, Bassett JR, Monroy JA. Active muscle stiffness is reduced during rapid unloading in muscles from TtnD112-158 mice with a large deletion to PEVK titin. J Exp Biol 2022; 225:276067. [DOI: 10.1242/jeb.243584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 07/13/2022] [Indexed: 11/20/2022]
Abstract
Evidence suggests that the giant muscle protein, titin functions as a tunable spring in active muscle. However, the mechanisms for increasing titin stiffness with activation are not well understood. Previous studies have suggested that during muscle activation, titin binds to actin which engages the PEVK region of titin thereby increasing titin stiffness. In this study, we investigated the role of PEVK titin in active muscle stiffness during rapid unloading. We measured elastic recoil of active and passive soleus muscles from TtnD112-158 mice characterized by a 75% deletion of PEVK titin and increased passive stiffness. We hypothesized that activated TtnD112-158 muscles are more stiff than wild type muscles due to the increased stiffness of PEVK titin. Using a servomotor force lever, we compared the stress–strain relationships of elastic elements in active and passive muscles during rapid unloading and quantified the change in stiffness upon activation. Results show that the elastic modulus of TtnD112-158 muscles increased with activation. However, elastic elements developed force at 7% longer lengths and exhibited 50% lower active stiffness in TtnD112-158 soleus muscles than wild type muscles. Thus, despite having a shorter, stiffer PEVK segment, during rapid unloading, TtnD112-158 soleus muscles exhibited reduced active stiffness compared to wild type soleus muscles. These results are consistent with the idea that PEVK titin contributes to active muscle stiffness, however, the reduction in active stiffness of TtnD112-158 muscles suggests that other mechanisms compensate for the increased PEVK stiffness.
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Affiliation(s)
| | | | - Jenna A. Monroy
- 3 W.M. Keck Science Department, Claremont Colleges, Claremont, CA, USA
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42
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Kötter S, Krüger M. Protein Quality Control at the Sarcomere: Titin Protection and Turnover and Implications for Disease Development. Front Physiol 2022; 13:914296. [PMID: 35846001 PMCID: PMC9281568 DOI: 10.3389/fphys.2022.914296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
Sarcomeres are mainly composed of filament and signaling proteins and are the smallest molecular units of muscle contraction and relaxation. The sarcomere protein titin serves as a molecular spring whose stiffness mediates myofilament extensibility in skeletal and cardiac muscle. Due to the enormous size of titin and its tight integration into the sarcomere, the incorporation and degradation of the titin filament is a highly complex task. The details of the molecular processes involved in titin turnover are not fully understood, but the involvement of different intracellular degradation mechanisms has recently been described. This review summarizes the current state of research with particular emphasis on the relationship between titin and protein quality control. We highlight the involvement of the proteasome, autophagy, heat shock proteins, and proteases in the protection and degradation of titin in heart and skeletal muscle. Because the fine-tuned balance of degradation and protein expression can be disrupted under pathological conditions, the review also provides an overview of previously known perturbations in protein quality control and discusses how these affect sarcomeric proteins, and titin in particular, in various disease states.
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Contini M, Altman D, Cornachione A, Rassier DE, Bagni MA. An increase in force after stretch of diaphragm fibers and myofibrils is accompanied by an increase in sarcomere length non-uniformities and Ca 2+ sensitivity. Am J Physiol Cell Physiol 2022; 323:C14-C28. [PMID: 35613356 DOI: 10.1152/ajpcell.00394.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When muscle fibers from limb muscles are stretched while activated, the force increases to a steady-state level that is higher than that produced during isometric contractions at a corresponding sarcomere length, a phenomenon known as residual force enhancement (RFE). The mechanisms responsible for the RFE are an increased stiffness of titin molecules which may lead to an increased Ca2+ sensitivity of the contractile apparatus,and the development of sarcomere length non-uniformities. RFE is not observed in cardiac muscles, which makes this phenomenon specific to certain preparations. The aim of this study was to investigate if the RFE is present in the diaphragm, and its potential association with an increased Ca2+ sensitivity and the development of sarcomere length non-uniformities. We used two preparations: single intact fibers and myofibrils isolated from the diaphragm from mice. We investigated RFE in a variety of lengths across the force-length relationship. RFE was observed in both preparations at all lengths investigated, and was larger with increasing magnitudes of stretch. RFE was accompanied by an increased Ca2+ sensitivity as shown by a change in the force-pCa2+-curve, and increased sarcomere length non-uniformities. Therefore, RFE is a phenomenon commonly observed in skeletal muscles, with mechanisms that are similar across preparations.
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Affiliation(s)
- Massimo Contini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - David Altman
- Department of Physics, Willamette University, Salem, OR, United States
| | - Anabelle Cornachione
- Department of Physiological Sciences, Federal University of São Carlos, São Paulo, Brazil
| | | | - Maria Angela Bagni
- Department of Experimental and Clinical Medicine, University of Florence, Italy
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Array Comparative Genomic Hybridisation and Droplet Digital PCR Uncover Recurrent Copy Number Variation of the TTN Segmental Duplication Region. Genes (Basel) 2022; 13:genes13050905. [PMID: 35627290 PMCID: PMC9142044 DOI: 10.3390/genes13050905] [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: 04/07/2022] [Revised: 05/13/2022] [Accepted: 05/17/2022] [Indexed: 02/04/2023] Open
Abstract
Intragenic segmental duplication regions are potential hotspots for recurrent copy number variation and possible pathogenic aberrations. Two large sarcomeric genes, nebulin and titin, both contain such segmental duplication regions. Using our custom Comparative Genomic Hybridisation array, we have previously shown that a gain or loss of more than one copy of the repeated block of the nebulin triplicate region constitutes a recessive pathogenic mutation. Using targeted array-CGH, similar copy number variants can be detected in the segmental duplication region of titin. Due to the limitations of the array-CGH methodology and the repetitiveness of the region, the exact copy numbers of the blocks could not be determined. Therefore, we developed complementary custom Droplet Digital PCR assays for the titin segmental duplication region to confirm true variation. Our combined methods show that the titin segmental duplication region is subject to recurrent copy number variation. Gains and losses were detected in samples from healthy individuals as well as in samples from patients with different muscle disorders. The copy number variation observed in our cohort is likely benign, but pathogenic copy number variants in the segmental duplication region of titin cannot be excluded. Further investigations are needed, however, this region should no longer be neglected in genetic analyses.
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Novel compound heterozygous mutations in the TTN gene: elongation and truncation variants causing limb-girdle muscular dystrophy type 2J in a Han Chinese family. Neurol Sci 2022; 43:3427-3433. [DOI: 10.1007/s10072-022-05979-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/18/2022] [Indexed: 10/18/2022]
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Querceto S, Santoro R, Gowran A, Grandinetti B, Pompilio G, Regnier M, Tesi C, Poggesi C, Ferrantini C, Pioner JM. The harder the climb the better the view: The impact of substrate stiffness on cardiomyocyte fate. J Mol Cell Cardiol 2022; 166:36-49. [PMID: 35139328 DOI: 10.1016/j.yjmcc.2022.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 12/22/2021] [Accepted: 02/02/2022] [Indexed: 12/27/2022]
Abstract
The quest for novel methods to mature human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for cardiac regeneration, modelling and drug testing has emphasized a need to create microenvironments with physiological features. Many studies have reported on how cardiomyocytes sense substrate stiffness and adapt their morphological and functional properties. However, these observations have raised new biological questions and a shared vision to translate it into a tissue or organ context is still elusive. In this review, we will focus on the relevance of substrates mimicking cardiac extracellular matrix (cECM) rigidity for the understanding of the biomechanical crosstalk between the extracellular and intracellular environment. The ability to opportunely modulate these pathways could be a key to regulate in vitro hiPSC-CM maturation. Therefore, both hiPSC-CM models and substrate stiffness appear as intriguing tools for the investigation of cECM-cell interactions. More understanding of these mechanisms may provide novel insights on how cECM affects cardiac cell function in the context of genetic cardiomyopathies.
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Affiliation(s)
- Silvia Querceto
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | - Rosaria Santoro
- Unità di Biologia Vascolare e Medicina Rigenerativa, Centro Cardiologico Monzino IRCCS, via Carlo Parea 4, Milan, Italy; Department of Electronics, Information and Biomedical Engineering, Politecnico di Milano, Milan, Italy
| | - Aoife Gowran
- Unità di Biologia Vascolare e Medicina Rigenerativa, Centro Cardiologico Monzino IRCCS, via Carlo Parea 4, Milan, Italy
| | - Bruno Grandinetti
- European Laboratory for Non-Linear Spectroscopy (LENS), Sesto Fiorentino, FI, Italy
| | - Giulio Pompilio
- Unità di Biologia Vascolare e Medicina Rigenerativa, Centro Cardiologico Monzino IRCCS, via Carlo Parea 4, Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, University of Milan, Italy
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Chiara Tesi
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | - Corrado Poggesi
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | - Cecilia Ferrantini
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | - Josè Manuel Pioner
- Department of Biology, Università degli Studi di Firenze, Florence, Italy.
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Panwar D, Singh KG, Mathur S, Prasad B, Joshi A, Lal V, Thatai A. Heterozygous missense variant in the TTN gene causing Tibial muscular dystrophy. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00284-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Tibial muscular dystrophy (TMD), tardive, is a dominantly inherited mild degenerative disorder of anterior tibial muscles. Mutations of Titin (TTN) have been reported in patients with different phenotypes such as skeletal muscular abnormalities or complex overlapping disorders of muscles. Titin (TTN) is a large 363 exon gene that encodes an abundant protein (the longest polypeptide known in nature) expressed in the heart and skeletal muscles.
Methods
DNA from peripheral blood sample was extracted, whole exome sequencing (WES) was performed, and a neuromuscular disorders related gene-filtering strategy was used to analyse the disease-causing mutations. Further, sanger sequencing was applied to confirm the variant.
Results
A novel missense variant (c.41529G > C;p.Arg13843Ser) of TTN gene was identified in a patient with lower limb weakness, occasional tongue fasciculation and mild scoliosis. This variant leads to a substitution of arginine with serine, causing structural changes in titin protein that is responsible for the TMD disease.
Conclusion
The novel variant detected has widened the genetic spectrum of TTN-associated diseases, further functional studies will aid in establishing the clinical diagnosis.
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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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Ford M, Hari A, Rodriguez O, Xu J, Lack J, Oguz C, Zhang Y, Weber S, Magglioco M, Barnett J, Xirasagar S, Samuel S, Imberti L, Bonfanti P, Biondi A, Dalgard CL, Chanock S, Rosen L, Holland S, Su H, Notarangelo L, Vishkin U, Watson C, Sahinalp SC. ImmunoTyper-SR: A Novel Computational Approach for Genotyping Immunoglobulin Heavy Chain Variable Genes using Short Read Data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.01.31.478564. [PMID: 35132409 PMCID: PMC8820654 DOI: 10.1101/2022.01.31.478564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human immunoglobulin heavy chain (IGH) locus on chromosome 14 includes more than 40 functional copies of the variable gene (IGHV), which, together with the joining genes (IGHJ), diversity genes (IGHD), constant genes (IGHC) and immunoglobulin light chains, code for antibodies that identify and neutralize pathogenic invaders as a part of the adaptive immune system. Because of its highly repetitive sequence composition, the IGH locus has been particularly difficult to assemble or genotype through the use of standard short read sequencing technologies. Here we introduce ImmunoTyper-SR, an algorithmic method for genotype and CNV analysis of the germline IGHV genes using Illumina whole genome sequencing (WGS) data. ImmunoTyper-SR is based on a novel combinatorial optimization formulation that aims to minimize the total edit distance between reads and their assigned IGHV alleles from a given database, with constraints on the number and distribution of reads across each called allele. We have validated ImmunoTyper-SR on 12 individuals with Illumina WGS data from the 1000 Genomes Project, whose IGHV allele composition have been studied extensively through the use of long read and targeted sequencing platforms, as well as nine individuals from the NIAID COVID Consortium who have been subjected to WGS twice. We have then applied ImmunoTyper-SR on 585 samples from the NIAID COVID Consortium to investigate associations between distinct IGHV alleles and anti-type I IFN autoantibodies which have been linked to COVID-19 severity.
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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: 7] [Impact Index Per Article: 3.5] [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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