1
|
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.
Collapse
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
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Guerra J, Matta L, Bartelt A. Cardiac proteostasis in obesity and cardiovascular disease. Herz 2024; 49:118-123. [PMID: 38329532 PMCID: PMC10917825 DOI: 10.1007/s00059-024-05233-6] [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] [Accepted: 01/17/2024] [Indexed: 02/09/2024]
Abstract
Cardiovascular diseases (CVD) are closely linked to protein homeostasis (proteostasis) and its failure. Beside genetic mutations that impair cardiac protein quality control, obesity is a strong risk factor for heart disease. In obesity, adipose tissue becomes dysfunctional and impacts heart function and CVD progression by releasing cytokines that contribute to systemic insulin resistance and cardiovascular dysfunction. In addition, chronic inflammation and lipotoxicity compromise endoplasmic reticulum (ER) function, eliciting stress responses that overwhelm protein quality control beyond its capacity. Impairment of proteostasis-including dysfunction of the ubiquitin-proteasome system (UPS), autophagy, and the depletion of chaperones-is intricately linked to cardiomyocyte dysfunction. Interventions targeting UPS and autophagy pathways are new potential strategies for re-establishing protein homeostasis and improving heart function. Additionally, lifestyle modifications such as dietary interventions and exercise have been shown to promote cardiac proteostasis and overall metabolic health. The pursuit of future research dedicated to proteostasis and protein quality control represents a pioneering approach for enhancing cardiac health and addressing the complexities of obesity-related cardiac dysfunction.
Collapse
Affiliation(s)
- Joel Guerra
- Institute for Cardiovascular Prevention (IPEK), Faculty of Medicine, Ludwig-Maximilians-Universität München, Max-Lebsche-Platz 30, 81377, Munich, Germany
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Leonardo Matta
- Institute for Cardiovascular Prevention (IPEK), Faculty of Medicine, Ludwig-Maximilians-Universität München, Max-Lebsche-Platz 30, 81377, Munich, Germany
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Alexander Bartelt
- Institute for Cardiovascular Prevention (IPEK), Faculty of Medicine, Ludwig-Maximilians-Universität München, Max-Lebsche-Platz 30, 81377, Munich, Germany.
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany.
- German Center for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany.
- German Center for Diabetes Research, Neuherberg, Germany.
| |
Collapse
|
4
|
Lepley LK, Stoneback L, Macpherson PC, Butterfield TA. Eccentric Exercise as a Potent Prescription for Muscle Weakness After Joint Injury. Exerc Sport Sci Rev 2023; 51:109-116. [PMID: 37093645 PMCID: PMC10330137 DOI: 10.1249/jes.0000000000000319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Lengthening contractions (i.e., eccentric contractions) are capable of uniquely triggering the nervous system and signaling pathways to promote tissue health/growth. This mode of exercise may be particularly potent for patients suffering from muscle weakness after joint injury. Here we provide a novel framework for eccentric exercise as a safe, effective mode of exercise prescription for muscle recovery.
Collapse
Affiliation(s)
| | - Luke Stoneback
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
| | - Peter C.D. Macpherson
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy A. Butterfield
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| |
Collapse
|
5
|
Valero-Muñoz M, Saw EL, Hekman RM, Blum BC, Hourani Z, Granzier H, Emili A, Sam F. Proteomic and phosphoproteomic profiling in heart failure with preserved ejection fraction (HFpEF). Front Cardiovasc Med 2022; 9:966968. [PMID: 36093146 PMCID: PMC9452734 DOI: 10.3389/fcvm.2022.966968] [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: 06/12/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Although the prevalence of heart failure with preserved ejection fraction (HFpEF) is increasing, evidence-based therapies for HFpEF remain limited, likely due to an incomplete understanding of this disease. This study sought to identify the cardiac-specific features of protein and phosphoprotein changes in a murine model of HFpEF using mass spectrometry. HFpEF mice demonstrated moderate hypertension, left ventricle (LV) hypertrophy, lung congestion and diastolic dysfunction. Proteomics analysis of the LV tissue showed that 897 proteins were differentially expressed between HFpEF and Sham mice. We observed abundant changes in sarcomeric proteins, mitochondrial-related proteins, and NAD-dependent protein deacetylase sirtuin-3 (SIRT3). Upregulated pathways by GSEA analysis were related to immune modulation and muscle contraction, while downregulated pathways were predominantly related to mitochondrial metabolism. Western blot analysis validated SIRT3 downregulated cardiac expression in HFpEF vs. Sham (0.8 ± 0.0 vs. 1.0 ± 0.0; P < 0.001). Phosphoproteomics analysis showed that 72 phosphosites were differentially regulated between HFpEF and Sham LV. Aberrant phosphorylation patterns mostly occurred in sarcomere proteins and nuclear-localized proteins associated with contractile dysfunction and cardiac hypertrophy. Seven aberrant phosphosites were observed at the z-disk binding region of titin. Additional agarose gel analysis showed that while total titin cardiac expression remained unaltered, its stiffer N2B isoform was significantly increased in HFpEF vs. Sham (0.144 ± 0.01 vs. 0.127 ± 0.01; P < 0.05). In summary, this study demonstrates marked changes in proteins related to mitochondrial metabolism and the cardiac contractile apparatus in HFpEF. We propose that SIRT3 may play a role in perpetuating these changes and may be a target for drug development in HFpEF.
Collapse
Affiliation(s)
- María Valero-Muñoz
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: María Valero-Muñoz,
| | - Eng Leng Saw
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Ryan M. Hekman
- Department of Biology, Boston University, Boston, MA, United States
- Department of Biochemistry, Cell Biology and Genomics, Boston University, Boston, MA, United States
| | - Benjamin C. Blum
- Department of Biochemistry, Cell Biology and Genomics, Boston University, Boston, MA, United States
- Center for Network Systems Biology, Boston University, Boston, MA, United States
| | - Zaynab Hourani
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ, United States
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ, United States
| | - Andrew Emili
- Department of Biology, Boston University, Boston, MA, United States
- Department of Biochemistry, Cell Biology and Genomics, Boston University, Boston, MA, United States
| | - Flora Sam
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- Flora Sam,
| |
Collapse
|
6
|
Li N, Hang W, Shu H, Zhou N. RBM20, a Therapeutic Target to Alleviate Myocardial Stiffness via Titin Isoforms Switching in HFpEF. Front Cardiovasc Med 2022; 9:928244. [PMID: 35783855 PMCID: PMC9243441 DOI: 10.3389/fcvm.2022.928244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/30/2022] [Indexed: 12/05/2022] Open
Abstract
Increased myocardial stiffness is critically involved in heart diseases with impaired cardiac compliance, especially heart failure with preserved ejection fraction (HFpEF). Myocardial stiffness mainly derives from cardiomyocyte- and extracellular matrix (ECM)-derived passive stiffness. Titin, a major component of sarcomeres, participates in myocardial passive stiffness and stress-sensitive signaling. The ratio of two titin isoforms, N2BA to N2B, was validated to influence diastolic dysfunction via several pathways. RNA binding motif protein 20 (RBM20) is a well-studied splicing factor of titin, functional deficiency of RBM20 in mice profile improved cardiac compliance and function, which indicated that RBM20 functions as a potential therapeutic target for mitigating myocardial stiffness by modulating titin isoforms. This minor review summarized how RBM20 and other splicing factors modify the titin isoforms ratio, therefore providing a promising target for improving the myocardial compliance of HFpEF.
Collapse
|
7
|
van der Pijl RJ, Domenighetti AA, Sheikh F, Ehler E, Ottenheijm CAC, Lange S. The titin N2B and N2A regions: biomechanical and metabolic signaling hubs in cross-striated muscles. Biophys Rev 2021; 13:653-677. [PMID: 34745373 PMCID: PMC8553726 DOI: 10.1007/s12551-021-00836-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023] Open
Abstract
Muscle specific signaling has been shown to originate from myofilaments and their associated cellular structures, including the sarcomeres, costameres or the cardiac intercalated disc. Two signaling hubs that play important biomechanical roles for cardiac and/or skeletal muscle physiology are the N2B and N2A regions in the giant protein titin. Prominent proteins associated with these regions in titin are chaperones Hsp90 and αB-crystallin, members of the four-and-a-half LIM (FHL) and muscle ankyrin repeat protein (Ankrd) families, as well as thin filament-associated proteins, such as myopalladin. This review highlights biological roles and properties of the titin N2B and N2A regions in health and disease. Special emphasis is placed on functions of Ankrd and FHL proteins as mechanosensors that modulate muscle-specific signaling and muscle growth. This region of the sarcomere also emerged as a hotspot for the modulation of passive muscle mechanics through altered titin phosphorylation and splicing, as well as tethering mechanisms that link titin to the thin filament system.
Collapse
Affiliation(s)
| | - Andrea A. Domenighetti
- Shirley Ryan AbilityLab, Chicago, IL USA
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL USA
| | - Farah Sheikh
- Division of Cardiology, School of Medicine, UC San Diego, La Jolla, CA USA
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King’s College London, London, UK
| | - Coen A. C. Ottenheijm
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ USA
- Department of Physiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Stephan Lange
- Division of Cardiology, School of Medicine, UC San Diego, La Jolla, CA USA
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
8
|
Bogomolovas J, Fleming JR, Franke B, Manso B, Simon B, Gasch A, Markovic M, Brunner T, Knöll R, Chen J, Labeit S, Scheffner M, Peter C, Mayans O. Titin kinase ubiquitination aligns autophagy receptors with mechanical signals in the sarcomere. EMBO Rep 2021; 22:e48018. [PMID: 34402565 PMCID: PMC8490993 DOI: 10.15252/embr.201948018] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 12/13/2022] Open
Abstract
Striated muscle undergoes remodelling in response to mechanical and physiological stress, but little is known about the integration of such varied signals in the myofibril. The interaction of the elastic kinase region from sarcomeric titin (A168-M1) with the autophagy receptors Nbr1/p62 and MuRF E3 ubiquitin ligases is well suited to link mechanosensing with the trophic response of the myofibril. To investigate the mechanisms of signal cross-talk at this titin node, we elucidated its 3D structure, analysed its response to stretch using steered molecular dynamics simulations and explored its functional relation to MuRF1 and Nbr1/p62 using cellular assays. We found that MuRF1-mediated ubiquitination of titin kinase promotes its scaffolding of Nbr1/p62 and that the process can be dynamically down-regulated by the mechanical unfolding of a linker sequence joining titin kinase with the MuRF1 receptor site in titin. We propose that titin ubiquitination is sensitive to the mechanical state of the sarcomere, the regulation of sarcomere targeting by Nbr1/p62 being a functional outcome. We conclude that MuRF1/Titin Kinase/Nbr1/p62 constitutes a distinct assembly that predictably promotes sarcomere breakdown in inactive muscle.
Collapse
Affiliation(s)
- Julius Bogomolovas
- Department of MedicineSchool of MedicineUniversity of CaliforniaSan Diego, La JollaCAUSA
- Department of Cognitive and Clinical NeuroscienceCentral Institute of Mental HealthMedical Faculty MannheimHeidelberg UniversityMannheimGermany
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Barbara Franke
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Bruno Manso
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Bernd Simon
- Structural and Computational Biology UnitEMBLHeidelbergGermany
| | - Alexander Gasch
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Thomas Brunner
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Ralph Knöll
- Integrated Cardio Metabolic Centre (ICMC)Heart and Vascular ThemeUniversity Hospital, MedHKarolinska InstitutetHuddingeSweden
- Bioscience, CardiovascularRenal & MetabolismBioPharmaceuticalsR&D, AstraZenecaGothenburgSweden
| | - Ju Chen
- Department of MedicineSchool of MedicineUniversity of CaliforniaSan Diego, La JollaCAUSA
| | - Siegfried Labeit
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Christine Peter
- Department of ChemistryUniversity of KonstanzKonstanzGermany
| | - Olga Mayans
- Department of BiologyUniversity of KonstanzKonstanzGermany
| |
Collapse
|
9
|
Lo WL, Weiss A. Adapting T Cell Receptor Ligand Discrimination Capability via LAT. Front Immunol 2021; 12:673196. [PMID: 33936119 PMCID: PMC8085316 DOI: 10.3389/fimmu.2021.673196] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 03/29/2021] [Indexed: 12/19/2022] Open
Abstract
Self- and non-self ligand discrimination is a core principle underlying T cell-mediated immunity. Mature αβ T cells can respond to a foreign peptide ligand presented by major histocompatibility complex molecules (pMHCs) on antigen presenting cells, on a background of continuously sensed self-pMHCs. How αβ T cells can properly balance high sensitivity and high specificity to foreign pMHCs, while surrounded by a sea of self-peptide ligands is not well understood. Such discrimination cannot be explained solely by the affinity parameters of T cell antigen receptor (TCR) and pMHC interaction. In this review, we will discuss how T cell ligand discrimination may be molecularly defined by events downstream of the TCR-pMHC interaction. We will discuss new evidence in support of the kinetic proofreading model of TCR ligand discrimination, and in particular how the kinetics of specific phosphorylation sites within the adaptor protein linker for activation of T cells (LAT) determine the outcome of TCR signaling. In addition, we will discuss emerging data regarding how some kinases, including ZAP-70 and LCK, may possess scaffolding functions to more efficiently direct their kinase activities.
Collapse
Affiliation(s)
- Wan-Lin Lo
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, United States
| |
Collapse
|
10
|
Shenkman BS, Tsaturyan AK, Vikhlyantsev IM, Kozlovskaya IB, Grigoriev AI. Molecular Mechanisms of Muscle Tone Impairment under Conditions of Real and Simulated Space Flight. Acta Naturae 2021; 13:85-97. [PMID: 34377559 PMCID: PMC8327152 DOI: 10.32607/actanaturae.10953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/04/2020] [Indexed: 01/08/2023] Open
Abstract
Kozlovskaya et al. [1] and Grigoriev et al. [2] showed that enormous loss of muscle stiffness (atonia) develops in humans under true (space flight) and simulated microgravity conditions as early as after the first days of exposure. This phenomenon is attributed to the inactivation of slow motor units and called reflectory atonia. However, a lot of evidence indicating that even isolated muscle or a single fiber possesses substantial stiffness was published at the end of the 20th century. This intrinsic stiffness is determined by the active component, i.e. the ability to form actin-myosin cross-bridges during muscle stretch and contraction, as well as by cytoskeletal and extracellular matrix proteins, capable of resisting muscle stretch. The main facts on intrinsic muscle stiffness under conditions of gravitational unloading are considered in this review. The data obtained in studies of humans under dry immersion and rodent hindlimb suspension is analyzed. The results and hypotheses regarding reduced probability of cross-bridge formation in an atrophying muscle due to increased interfilament spacing are described. The evidence of cytoskeletal protein (titin, nebulin, etc.) degradation during gravitational unloading is also discussed. The possible mechanisms underlying structural changes in skeletal muscle collagen and its role in reducing intrinsic muscle stiffness are presented. The molecular mechanisms of changes in intrinsic stiffness during space flight and simulated microgravity are reviewed.
Collapse
Affiliation(s)
- B. S. Shenkman
- State Scientific Center of Russian Federation – Institute of Biomedical Problems, Moscow, 123007 Russia
| | - A. K. Tsaturyan
- Lomonosov Moscow State University Research Institute of Mechanics, Moscow, 119192 Russia
| | - I. M. Vikhlyantsev
- Institute of Experimental and Theoretical Biophysics, Moscow Region, Pushchino, 142290 Russia
| | - I. B. Kozlovskaya
- State Scientific Center of Russian Federation – Institute of Biomedical Problems, Moscow, 123007 Russia
| | - A. I. Grigoriev
- State Scientific Center of Russian Federation – Institute of Biomedical Problems, Moscow, 123007 Russia
| |
Collapse
|
11
|
Hang C, Song Y, Li Y, Zhang S, Chang Y, Bai R, Saleem A, Jiang M, Lu W, Lan F, Cui M. Knockout of MYOM1 in human cardiomyocytes leads to myocardial atrophy via impairing calcium homeostasis. J Cell Mol Med 2021; 25:1661-1676. [PMID: 33452765 PMCID: PMC7875908 DOI: 10.1111/jcmm.16268] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 12/27/2022] Open
Abstract
Myomesin-1 (encoded by MYOM1 gene) is expressed in almost all cross-striated muscles, whose family (together with myomesin-2 and myomesin-3) helps to cross-link adjacent myosin to form the M-line in myofibrils. However, little is known about its biological function, causal relationship and mechanisms underlying the MYOM1-related myopathies (especially in the heart). Regrettably, there is no MYMO1 knockout model for its study so far. A better and further understanding of MYOM1 biology is urgently needed. Here, we used CRISPR/Cas9 gene-editing technology to establish an MYOM1 knockout human embryonic stem cell line (MYOM1-/- hESC), which was then differentiated into myomesin-1 deficient cardiomyocytes (MYOM1-/- hESC-CMs) in vitro. We found that myomesin-1 plays an important role in sarcomere assembly, contractility regulation and cardiomyocytes development. Moreover, myomesin-1-deficient hESC-CMs can recapitulate myocardial atrophy phenotype in vitro. Based on this model, not only the biological function of MYOM1, but also the aetiology, pathogenesis, and potential treatments of myocardial atrophy caused by myomesin-1 deficiency can be studied.
Collapse
Affiliation(s)
- Chengwen Hang
- Department of CardiologyPeking University Third HospitalBeijingChina
| | - Yuanxiu Song
- Department of CardiologyPeking University Third HospitalBeijingChina
| | - Ya’nan Li
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Siyao Zhang
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Yun Chang
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Rui Bai
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Amina Saleem
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Mengqi Jiang
- Department of CardiologyPeking University Third HospitalBeijingChina
| | - Wenjing Lu
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Feng Lan
- Beijing Lab for Cardiovascular Precision MedicineAnzhen HospitalCapital Medical UniversityBeijingChina
| | - Ming Cui
- Department of CardiologyPeking University Third HospitalBeijingChina
| |
Collapse
|
12
|
Santiago CF, Huttner IG, Fatkin D. Mechanisms of TTNtv-Related Dilated Cardiomyopathy: Insights from Zebrafish Models. J Cardiovasc Dev Dis 2021; 8:jcdd8020010. [PMID: 33504111 PMCID: PMC7912658 DOI: 10.3390/jcdd8020010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/15/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a common heart muscle disorder characterized by ventricular dilation and contractile dysfunction that is associated with significant morbidity and mortality. New insights into disease mechanisms and strategies for treatment and prevention are urgently needed. Truncating variants in the TTN gene, which encodes the giant sarcomeric protein titin (TTNtv), are the most common genetic cause of DCM, but exactly how TTNtv promote cardiomyocyte dysfunction is not known. Although rodent models have been widely used to investigate titin biology, they have had limited utility for TTNtv-related DCM. In recent years, zebrafish (Danio rerio) have emerged as a powerful alternative model system for studying titin function in the healthy and diseased heart. Optically transparent embryonic zebrafish models have demonstrated key roles of titin in sarcomere assembly and cardiac development. The increasing availability of sophisticated imaging tools for assessment of heart function in adult zebrafish has revolutionized the field and opened new opportunities for modelling human genetic disorders. Genetically modified zebrafish that carry a human A-band TTNtv have now been generated and shown to spontaneously develop DCM with age. This zebrafish model will be a valuable resource for elucidating the phenotype modifying effects of genetic and environmental factors, and for exploring new drug therapies.
Collapse
Affiliation(s)
- Celine F. Santiago
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Inken G. Huttner
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Diane Fatkin
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
- Cardiology Department, St. Vincent’s Hospital, Darlinghurst, NSW 2010, Australia
- Correspondence:
| |
Collapse
|
13
|
Shenkman BS. How Postural Muscle Senses Disuse? Early Signs and Signals. Int J Mol Sci 2020; 21:E5037. [PMID: 32708817 PMCID: PMC7404025 DOI: 10.3390/ijms21145037] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/11/2022] Open
Abstract
A mammalian soleus muscle along with other "axial" muscles ensures the stability of the body under the Earth's gravity. In rat experiments with hindlimb suspension, zero-gravity parabolic flights as well as in human dry immersion studies, a dramatic decrease in the electromyographic (EMG) activity of the soleus muscle has been repeatedly shown. Most of the motor units of the soleus muscle convert from a state of activity to a state of rest which is longer than under natural conditions. And the state of rest gradually converts to the state of disuse. This review addresses a number of metabolic events that characterize the earliest stage of the cessation of the soleus muscle contractile activity. One to three days of mechanical unloading are accompanied by energy-dependent dephosphorylation of AMPK, accumulation of the reactive oxygen species, as well as accumulation of resting myoplasmic calcium. In this transition period, a rapid rearrangement of the various signaling pathways occurs, which, primarily, results in a decrease in the rate of protein synthesis (primarily via inhibition of ribosomal biogenesis and activation of endogenous inhibitors of mRNA translation, such as GSK3β) and an increase in proteolysis (via upregulation of muscle-specific E3-ubiquitin ligases).
Collapse
Affiliation(s)
- Boris S Shenkman
- Myology Laboratory, Institute of Biomedical Problems RAS, 123007 Moscow, Russia
| |
Collapse
|
14
|
Huang S, Liu S, Niu Y, Fu L. Scriptaid/exercise-induced lysine acetylation is another type of posttranslational modification occurring in titin. J Appl Physiol (1985) 2020; 128:276-285. [DOI: 10.1152/japplphysiol.00617.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Titin serves important functions in skeletal muscle during exercise, and posttranslational modifications of titin participate in the regulation of titin-based sarcomeric functions. Scriptaid has exercise-like effects through the inhibition of HDAC and regulatory acetylation of proteins. However, it remains mostly unclear if exercise could result in titin’s acetylation and whether Scriptaid could regulate acetylation of titin. We treated C57BL/6 mice with 6-wk treadmill exercise and 6-wk Scriptaid administration to explore Scriptaid’s effects on mice exercise capacity and whether Scriptaid administration/exercise could induce titin’s acetylation modification. An exercise endurance test was conducted to explore their effects on mice exercise capacity, and proteomic studies were conducted with gastrocnemius muscle tissue of mice from different groups to explore titin’s acetylation modification. We found that Scriptaid and exercise did not change titin’s protein expression, but they did induce acetylation modification changes of titin. In total, 333 acetylated lysine sites were identified. Exercise changed the acetylation levels of 33 lysine sites of titin, whereas Scriptaid changed acetylation levels of 31 titin lysine sites. Exercise treatment and Scriptaid administration shared 11 lysine sites. In conclusion, Scriptaid increased exercise endurance of mice by increasing the time mice spent running to fatigue. Acetylation is a common type of posttranslational modification of titin, and exercise/Scriptaid changed the acetylation levels of titin and titin-interacting proteins. Most importantly, titin may be a mediator through which Scriptaid and exercise modulate the properties and functions of exercise-induced skeletal muscle at the molecular level. NEW & NOTEWORTHY Scriptaid administration increased mouse exercise endurance. Acetylation is another type of posttranslational modification of titin. Scriptaid/exercise changed acetylation levels of titin and titin-interacting proteins. Titin may mediate exercise-induced skeletal muscle properties and functions.
Collapse
Affiliation(s)
- Song Huang
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, Tianjin, China
| | - Sujuan Liu
- Department of Anatomy and Embryology, School of Basic Medical Science, Tianjin Medical University, Tianjin, China
| | - Yanmei Niu
- Department of Rehabilitation, School of Medical Technology, Tianjin Medical University, Tianjin, China
| | - Li Fu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, Tianjin, China
- Department of Rehabilitation, School of Medical Technology, Tianjin Medical University, Tianjin, China
| |
Collapse
|
15
|
Monitoring Unfolding of Titin I27 Single and Bi Domain with High-Pressure NMR Spectroscopy. Biophys J 2019; 115:341-352. [PMID: 30021109 DOI: 10.1016/j.bpj.2018.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/26/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
A complete description of the pathways and mechanisms of protein folding requires a detailed structural and energetic characterization of the folding energy landscape. Simulations, when corroborated by experimental data yielding global information on the folding process, can provide this level of insight. Molecular dynamics (MD) has often been combined with force spectroscopy experiments to decipher the unfolding mechanism of titin immunoglobulin-like single or multidomain, the giant multimodular protein from sarcomeres, yielding information on the sequential events during titin unfolding under stretching. Here, we used high-pressure NMR to monitor the unfolding of titin I27 Ig-like single domain and tandem. Because this method brings residue-specific information on the folding process, it can provide quasiatomic details on this process without the help of MD simulations. Globally, the results of our high-pressure analysis are in agreement with previous results obtained by the combination of experimental measurements and MD simulation and/or protein engineering, although the intermediate folding state caused by the early detachment of the AB β-sheet, often reported in previous works based on MD or force spectroscopy, cannot be detected. On the other hand, the A'G parallel β-sheet of the β-sandwich has been confirmed as the Achilles heel of the three-dimensional scaffold: its disruption yields complete unfolding with very similar characteristics (free energy, unfolding volume, kinetics rate constants) for the two constructs.
Collapse
|
16
|
Salcan S, Bongardt S, Monteiro Barbosa D, Efimov IR, Rassaf T, Krüger M, Kötter S. Elastic titin properties and protein quality control in the aging heart. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118532. [PMID: 31421188 DOI: 10.1016/j.bbamcr.2019.118532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 07/12/2019] [Accepted: 08/12/2019] [Indexed: 01/09/2023]
Abstract
Cardiac aging affects the heart on the functional, structural, and molecular level and shares characteristic hallmarks with the development of chronic heart failure. Apart from age-dependent left ventricular hypertrophy and fibrosis that impairs diastolic function, diminished activity of cardiac protein-quality-control systems increases the risk of cytotoxic accumulation of defective proteins. Here, we studied the impact of cardiac aging on the sarcomeric protein titin by analyzing titin-based cardiomyocyte passive tension, titin modification and proteasomal titin turnover. We analyzed left ventricular samples from young (6 months) and old (20 months) wild-type mice and healthy human donor patients grouped according to age in young (17-50 years) and aged hearts (51-73 years). We found no age-dependent differences in titin isoform composition of mouse or human hearts. In aged hearts from mice and human we determined altered titin phosphorylation at serine residues S4010 and S4099 in the elastic N2B domain, but no significant changes in phosphorylation of S11878 and S12022 in the elastic PEVK region. Importantly, overall titin-based cardiomyocyte passive tension remained unchanged. In aged hearts, the calcium-activated protease calpain-1, which provides accessibility to ubiquitination by releasing titin from the sarcomere, showed decreased proteolytic activity. In addition, we observed a reduction in the proteasomal activities. Taken together, our data indicate that cardiac aging does not affect titin-based passive properties of the cardiomyocytes, but impairs protein-quality control, including titin, which may result in a diminished adaptive capacity of the aged myocardium.
Collapse
Affiliation(s)
- Senem Salcan
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Sabine Bongardt
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany
| | - David Monteiro Barbosa
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Igor R Efimov
- George Washington University, Department of Biomedical Engineering, Science and Engineering Hall, Washington DC-20052, USA
| | - Tienush Rassaf
- University Hospital Essen, Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, 45147 Essen, Germany
| | - Martina Krüger
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany.
| | - Sebastian Kötter
- Department of Cardiovascular Physiology, Medical Faculty, Heinrich Heine-University Düsseldorf, D-40225 Düsseldorf, Germany.
| |
Collapse
|
17
|
Weil BR, Techiryan G, Suzuki G, Konecny F, Canty JM. Adaptive Reductions in Left Ventricular Diastolic Compliance Protect the Heart From Stretch-Induced Stunning. JACC Basic Transl Sci 2019; 4:527-541. [PMID: 31468008 PMCID: PMC6712414 DOI: 10.1016/j.jacbts.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/19/2019] [Accepted: 04/20/2019] [Indexed: 11/04/2022]
Abstract
Swine subjected to 2 weeks of repetitive pressure overload (RPO) exhibited significant myocyte loss, but left ventricular (LV) systolic function was preserved, and chamber dilatation did not occur. Instead, myocardial remodeling characterized by myocyte hypertrophy and interstitial fibrosis led to a marked reduction in LV diastolic compliance, which protected the heart from stretch-induced myocyte injury and preserved LV ejection fraction without anatomic LV hypertrophy. These results support a novel paradigm that links cardiac adaptations to RPO with the pathogenesis of reduced LV diastolic compliance and may explain how LV stiffening can occur in the absence of sustained hypertension or anatomic hypertrophy.
Collapse
Key Words
- BP, blood pressure
- EDPVR, end-diastolic pressure−volume relationship
- HFpEF, heart failure with preserved ejection fraction
- LV, left ventricular
- LVEDP, left ventricular end-diastolic pressure
- LVEDV, left ventricular end-diastolic volume
- PE, phenylephrine
- PV, pressure−volume
- RPO, repetitive pressure overload
- TUNEL, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling
- cTnI, cardiac troponin I
- diastolic dysfunction
- fibrosis
- heart failure
- myocardial stunning
- stretch
- ΔEDP/ΔEDV, changes in end-diastolic pressure/end-diastolic volume
Collapse
Affiliation(s)
- Brian R. Weil
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York
- The Clinical and Translational Research Center, University at Buffalo, Buffalo, New York
| | - George Techiryan
- The Clinical and Translational Research Center, University at Buffalo, Buffalo, New York
- Department of Medicine, University at Buffalo, Buffalo, New York
| | - Gen Suzuki
- The Clinical and Translational Research Center, University at Buffalo, Buffalo, New York
- Department of Medicine, University at Buffalo, Buffalo, New York
| | - Filip Konecny
- Department of Surgery, McMaster University, Hamilton, Ontario, Canada
| | - John M. Canty
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York
- The Clinical and Translational Research Center, University at Buffalo, Buffalo, New York
- Department of Medicine, University at Buffalo, Buffalo, New York
- VA WNY Health Care System, Buffalo, New York
- Department of Biomedical Engineering, University at Buffalo, Buffalo, New York
| |
Collapse
|
18
|
Freundt JK, Linke WA. Titin as a force-generating muscle protein under regulatory control. J Appl Physiol (1985) 2018; 126:1474-1482. [PMID: 30521425 DOI: 10.1152/japplphysiol.00865.2018] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Titin has long been recognized as a mechanical protein in muscle cells that has a main function as a molecular spring in the contractile units, the sarcomeres. Recent work suggests that the titin spring contributes to muscle contraction in a more active manner than previously thought. In this review, we highlight this property, specifically the ability of the immunoglobulin-like (Ig) domains of titin to undergo unfolding-refolding transitions when isolated titin molecules or skeletal myofibrils are held at physiological force levels. Folding of titin Ig domains under force is a hitherto unappreciated, putative source of work production in muscle cells, which could work in synergy with the actomyosin system to maximize the energy delivered by a stretched, actively contracting muscle. This review also focuses on the mechanisms shown to modulate titin-based viscoelastic forces in skeletal muscle cells, including chaperone binding, titin oxidation, phosphorylation, Ca2+ binding, and interaction with actin filaments. Along the way, we discuss which of these modulatory mechanisms might contribute to the phenomenon of residual force enhancement relevant for eccentric muscle contractions. Finally, a brief perspective is added on the potential for the alterations in titin-based force to dynamically alter mechano-chemical signaling pathways in the muscle cell. We conclude that titin from skeletal muscle is a determinant of both passive and active tension and a bona fide mechanosensor, whose stiffness is tuned by various independent mechanisms.
Collapse
Affiliation(s)
- Johanna K Freundt
- Institute of Physiology II, University of Muenster , Muenster , Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University of Muenster , Muenster , Germany
| |
Collapse
|
19
|
Calcium increases titin N2A binding to F-actin and regulated thin filaments. Sci Rep 2018; 8:14575. [PMID: 30275509 PMCID: PMC6167357 DOI: 10.1038/s41598-018-32952-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/19/2018] [Indexed: 12/30/2022] Open
Abstract
Mutations in titin are responsible for many cardiac and muscle diseases, yet the underlying mechanisms remain largely unexplained. Numerous studies have established roles for titin in muscle function, and Ca2+-dependent interactions between titin and actin have been suggested to play a role in muscle contraction. The present study used co-sedimentation assays, dynamic force spectroscopy (DFS), and in vitro motility (IVM) assays to determine whether the N2A region of titin, overlooked in previous studies, interacts with actin in the presence of Ca2+. Co-sedimentation demonstrated that N2A – F-actin binding increases with increasing protein and Ca2+ concentration, DFS demonstrated increased rupture forces and decreased koff in the presence of Ca2+, and IVM demonstrated a Ca2+-dependent reduction in motility of F-actin and reconstituted thin filaments in the presence of N2A. These results indicate that Ca2+ increases the strength and stability of N2A – actin interactions, supporting the hypothesis that titin plays a regulatory role in muscle contraction. The results further support a model in which N2A – actin binding in active muscle increases titin stiffness, and that impairment of this mechanism contributes to the phenotype in muscular dystrophy with myositis. Future studies are required to determine whether titin – actin binding occurs in skeletal muscle sarcomeres in vivo.
Collapse
|
20
|
Hopf AE, Andresen C, Kötter S, Isić M, Ulrich K, Sahin S, Bongardt S, Röll W, Drove F, Scheerer N, Vandekerckhove L, De Keulenaer GW, Hamdani N, Linke WA, Krüger M. Diabetes-Induced Cardiomyocyte Passive Stiffening Is Caused by Impaired Insulin-Dependent Titin Modification and Can Be Modulated by Neuregulin-1. Circ Res 2018; 123:342-355. [PMID: 29760016 DOI: 10.1161/circresaha.117.312166] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 05/05/2018] [Accepted: 05/11/2018] [Indexed: 12/17/2022]
Abstract
RATIONALE Increased titin-dependent cardiomyocyte tension is a hallmark of heart failure with preserved ejection fraction associated with type-2 diabetes mellitus. However, the insulin-related signaling pathways that modify titin-based cardiomyocyte tension, thereby contributing to modulation of diastolic function, are largely unknown. OBJECTIVE We aimed to determine how impaired insulin signaling affects titin expression and phosphorylation and thus increases passive cardiomyocyte tension, and whether metformin or neuregulin-1 (NRG-1) can correct disturbed titin modifications and increased titin-based stiffness. METHODS AND RESULTS We used cardiac biopsies from human diabetic (n=23) and nondiabetic patients (n=19), cultured rat cardiomyocytes, left ventricular tissue from apolipoprotein E-deficient mice with streptozotocin-induced diabetes mellitus (n=12-22), and ZSF1 (obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid) rats (n=5-6) and analyzed insulin-dependent signaling pathways that modulate titin phosphorylation. Titin-based passive tension was measured using permeabilized cardiomyocytes. In human diabetic hearts, we detected titin hypophosphorylation at S4099 and hyperphosphorylation at S11878, suggesting altered activity of protein kinases; cardiomyocyte passive tension was significantly increased. When applied to cultured cardiomyocytes, insulin and metformin increased titin phosphorylation at S4010, S4099, and S11878 via enhanced ERK1/2 (extracellular signal regulated kinase 1/2) and PKCα (protein kinase Cα) activity; NRG-1 application enhanced ERK1/2 activity but reduced PKCα activity. In apolipoprotein E-deficient mice, chronic treatment of streptozotocin-induced diabetes mellitus with NRG-1 corrected titin phosphorylation via increased PKG (protein kinase G) and ERK1/2 activity and reduced PKCα activity, which reversed the diabetes mellitus-associated changes in titin-based passive tension. Acute application of NRG-1 to obese ZSF1 rats with type-2 diabetes mellitus reduced end-diastolic pressure. CONCLUSIONS Mechanistically, we found that impaired cGMP-PKG signaling and elevated PKCα activity are key modulators of titin-based cardiomyocyte stiffening in diabetic hearts. We conclude that by restoring normal kinase activities of PKG, ERK1/2, and PKCα, and by reducing cardiomyocyte passive tension, chronic NRG-1 application is a promising approach to modulate titin properties in heart failure with preserved ejection fraction associated with type-2 diabetes mellitus.
Collapse
Affiliation(s)
- Anna-Eliane Hopf
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Christian Andresen
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Sebastian Kötter
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Małgorzata Isić
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Kamila Ulrich
- Department of Systems Physiology, Ruhr-University Bochum, Germany (K.U., N.H.)
| | - Senem Sahin
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Sabine Bongardt
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| | - Wilhelm Röll
- Department of Cardiovascular Surgery, University Clinic Bonn, Germany (W.R.)
| | - Felicitas Drove
- Bayer AG, Drug Discovery, Pharmaceuticals, Wuppertal, Germany (F.D., N.S.)
| | - Nina Scheerer
- Bayer AG, Drug Discovery, Pharmaceuticals, Wuppertal, Germany (F.D., N.S.)
| | - Leni Vandekerckhove
- Department of Pharmaceutical Sciences, Laboratory of Physiopharmacology, Campus Drie Eiken, University of Antwerp, Belgium (L.V., G.W.D.)
| | - Gilles W De Keulenaer
- Department of Pharmaceutical Sciences, Laboratory of Physiopharmacology, Campus Drie Eiken, University of Antwerp, Belgium (L.V., G.W.D.)
| | - Nazha Hamdani
- Department of Systems Physiology, Ruhr-University Bochum, Germany (K.U., N.H.)
| | - Wolfgang A Linke
- Institute of Physiology II, University of Munster, Germany (W.A.L.)
| | - Martina Krüger
- From the Medical Faculty, Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany (A.-E.H., C.A., S.K., M.I., S.S., S.B., M.K.)
| |
Collapse
|
21
|
Immunotherapy with CAR-Modified T Cells: Toxicities and Overcoming Strategies. J Immunol Res 2018; 2018:2386187. [PMID: 29850622 PMCID: PMC5932485 DOI: 10.1155/2018/2386187] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 02/07/2018] [Indexed: 12/11/2022] Open
Abstract
T cells modified via chimeric antigen receptors (CARs) have emerged as a promising treatment modality. Unparalleled clinical efficacy recently demonstrated in refractory B-cell malignancy has brought this new form of adoptive immunotherapy to the center stage. Nonetheless, its current success has also highlighted its potential treatment-related toxicities. The adverse events observed in the clinical trials are described in this review, after which, some innovative strategies developed to overcome these unwanted toxicities are outlined, including suicide genes, targeted activation, and other novel strategies.
Collapse
|
22
|
Guo W, Sun M. RBM20, a potential target for treatment of cardiomyopathy via titin isoform switching. Biophys Rev 2018; 10:15-25. [PMID: 28577155 PMCID: PMC5803173 DOI: 10.1007/s12551-017-0267-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/16/2017] [Indexed: 12/18/2022] Open
Abstract
Cardiomyopathy, also known as heart muscle disease, is an unfavorable condition leading to alterations in myocardial contraction and/or impaired ability of ventricular filling. The onset and development of cardiomyopathy have not currently been well defined. Titin is a giant multifunctional sarcomeric filament protein that provides passive stiffness to cardiomyocytes and has been implicated to play an important role in the origin and development of cardiomyopathy and heart failure. Titin-based passive stiffness can be mainly adjusted by isoform switching and post-translational modifications in the spring regions. Recently, genetic mutations of TTN have been identified that can also contribute to variable passive stiffness, though the detailed mechanisms remain unclear. In this review, we will discuss titin isoform switching as it relates to alternative splicing during development stages and differences between species and muscle types. We provide an update on the regulatory mechanisms of TTN splicing controlled by RBM20 and cover the roles of TTN splicing in adjusting the diastolic stiffness and systolic compliance of the healthy and the failing heart. Finally, this review attempts to provide future directions for RBM20 as a potential target for pharmacological intervention in cardiomyopathy and heart failure.
Collapse
Affiliation(s)
- Wei Guo
- Animal Science, University of Wyoming, Laramie, WY, 82071, USA.
- Center for Cardiovascular Research and Integrative Medicine, University of Wyoming, Laramie, WY, 82071, USA.
| | - Mingming Sun
- Animal Science, University of Wyoming, Laramie, WY, 82071, USA
- Center for Cardiovascular Research and Integrative Medicine, University of Wyoming, Laramie, WY, 82071, USA
| |
Collapse
|
23
|
Baumert P, Lake MJ, Drust B, Stewart CE, Erskine RM. TRIM63 (MuRF-1) gene polymorphism is associated with biomarkers of exercise-induced muscle damage. Physiol Genomics 2017; 50:142-143. [PMID: 29212849 PMCID: PMC5899231 DOI: 10.1152/physiolgenomics.00103.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unaccustomed strenuous exercise can lead to muscle strength loss, inflammation and delayed-onset muscle soreness, which may be influenced by genetic variation. We investigated if a missense single nucleotide polymorphism (A>G, rs2275950 ) within the TRIM63 gene (encoding MuRF-1 and potentially affecting titin mechanical properties) was associated with the variable response to unaccustomed eccentric exercise. Sixty-five untrained, healthy participants (genotyped for rs2275950 : AA, AG, and GG) performed 120 maximal eccentric knee extensions (ECC) to induce muscle damage. Isometric and isokinetic maximal voluntary knee extension contractions (MVCs) and muscle soreness were assessed before, immediately after, and 48 h after ECC. AA homozygotes were consistently stronger [baseline isometric MVC: 3.23 ± 0.92 Nm/kg (AA) vs. 2.09 ± 0.67 Nm/kg (GG); P = 0.006] and demonstrated less muscle soreness over time ( P = 0.022) compared with GG homozygotes. This may be explained by greater titin stiffness in AA homozygotes, leading to intrinsically stronger muscle fibers that are more resistant to eccentric damaging contractions.
Collapse
Affiliation(s)
- P Baumert
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - M J Lake
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - B Drust
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - C E Stewart
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - R M Erskine
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Institute of Sport, Exercise & Health, University College London, London, United Kingdom
| |
Collapse
|
24
|
Genetic epidemiology of titin-truncating variants in the etiology of dilated cardiomyopathy. Biophys Rev 2017; 9:207-223. [PMID: 28510119 PMCID: PMC5498329 DOI: 10.1007/s12551-017-0265-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/10/2017] [Indexed: 02/07/2023] Open
Abstract
Heart failure (HF) is a complex clinical syndrome defined by the inability of the heart to pump enough blood to meet the body's metabolic demands. Major causes of HF are cardiomyopathies (diseases of the myocardium associated with mechanical and/or electrical dysfunction), among which the most common form is dilated cardiomyopathy (DCM). DCM is defined by ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness, which leads to progressive HF. Over 60 genes are linked to the etiology of DCM. Titin (TTN) is the largest known protein in biology, spanning half the cardiac sarcomere and, as such, is a basic structural and functional unit of striated muscles. It is essential for heart development as well as mechanical and regulatory functions of the sarcomere. Next-generation sequencing (NGS) in clinical DCM cohorts implicated truncating variants in titin (TTNtv) as major disease alleles, accounting for more than 25% of familial DCM cases, but these variants have also been identified in 2-3% of the general population, where these TTNtv blur diagnostic and clinical utility. Taking into account the published TTNtv and their association to DCM, it becomes clear that TTNtv harm the heart with position-dependent occurrence, being more harmful when present in the A-band TTN, presumably with dominant negative/gain-of-function mechanisms. However, these insights are challenged by the depiction of position-independent toxicity of TTNtv acting via haploinsufficient alleles, which are sufficient to induce cardiac pathology upon stress. In the current review, we provide an overview of TTN and discuss studies investigating various TTN mutations. We also present an overview of different mechanisms postulated or experimentally validated in the pathogenicity of TTNtv. DCM-causing genes are also discussed with respect to non-truncating mutations in the etiology of DCM. One way of understanding pathogenic variants is probably to understand the context in which they may or may not affect protein-protein interactions, changes in cell signaling, and substrate specificity. In this regard, we also provide a brief overview of TTN interactions in situ. Quantitative models in the risk assessment of TTNtv are also discussed. In summary, we highlight the importance of gene-environment interactions in the etiology of DCM and further mechanistic studies used to delineate the pathways which could be targeted in the management of DCM.
Collapse
|
25
|
Kötter S, Kazmierowska M, Andresen C, Bottermann K, Grandoch M, Gorressen S, Heinen A, Moll JM, Scheller J, Gödecke A, Fischer JW, Schmitt JP, Krüger M. Titin-Based Cardiac Myocyte Stiffening Contributes to Early Adaptive Ventricular Remodeling After Myocardial Infarction. Circ Res 2016; 119:1017-1029. [DOI: 10.1161/circresaha.116.309685] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/15/2016] [Indexed: 01/09/2023]
Abstract
Rationale:
Myocardial infarction (MI) increases the wall stress in the viable myocardium and initiates early adaptive remodeling in the left ventricle to maintain cardiac output. Later remodeling processes include fibrotic reorganization that eventually leads to cardiac failure. Understanding the mechanisms that support cardiac function in the early phase post MI and identifying the processes that initiate transition to maladaptive remodeling are of major clinical interest.
Objective:
To characterize MI-induced changes in titin-based cardiac myocyte stiffness and to elucidate the role of titin in ventricular remodeling of remote myocardium in the early phase after MI.
Methods and Results:
Titin properties were analyzed in Langendorff-perfused mouse hearts after 20-minute ischemia/60-minute reperfusion (I/R), and mouse hearts that underwent ligature of the left anterior descending coronary artery for 3 or 10 days. Cardiac myocyte passive tension was significantly increased 1 hour after ischemia/reperfusion and 3 and 10 days after left anterior descending coronary artery ligature. The increased passive tension was caused by hypophosphorylation of the titin N2-B unique sequence and hyperphosphorylation of the PEVK (titin domain rich in proline, glutamate, valine, and lysine) region of titin. Blocking of interleukine-6 before left anterior descending coronary artery ligature restored titin-based myocyte tension after MI, suggesting that MI-induced titin stiffening is mediated by elevated levels of the cytokine interleukine-6. We further demonstrate that the early remodeling processes 3 days after MI involve accelerated titin turnover by the ubiquitin–proteasome system.
Conclusions:
We conclude that titin-based cardiac myocyte stiffening acutely after MI is partly mediated by interleukine-6 and is an important mechanism of remote myocardium to adapt to the increased mechanical demands after myocardial injury.
Collapse
Affiliation(s)
- Sebastian Kötter
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Malgorzata Kazmierowska
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Christian Andresen
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Katharina Bottermann
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Maria Grandoch
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Simone Gorressen
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Andre Heinen
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Jens M. Moll
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Jürgen Scheller
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Axel Gödecke
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Jens W. Fischer
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Joachim P. Schmitt
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| | - Martina Krüger
- From the Department of Cardiovascular Physiology (S.K., M.K., C.A., K.B., A.H., A.G., M.K.), Department of Pharmacology and Clinical Pharmacology (M.G., S.G., J.W.F., J.P.S.), and Institute of Biochemistry and Molecular Biology II (J.M.M., J.S.), Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
| |
Collapse
|
26
|
Structural advances on titin: towards an atomic understanding of multi-domain functions in myofilament mechanics and scaffolding. Biochem Soc Trans 2016; 43:850-5. [PMID: 26517893 DOI: 10.1042/bst20150084] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Titin is a gigantic filamentous protein of the muscle sarcomere that plays roles in myofibril mechanics and homoeostasis. 3D-structures of multi-domain fragments of titin are now available that start revealing the molecular mechanisms governing its mechanical and scaffolding functions. This knowledge is now being translated into the fabrication of self-assembling biopolymers. Here we review the structural advances on titin, the novel concepts derived from these and the emerging translational avenues.
Collapse
|
27
|
Toxicity and management in CAR T-cell therapy. MOLECULAR THERAPY-ONCOLYTICS 2016; 3:16011. [PMID: 27626062 PMCID: PMC5008265 DOI: 10.1038/mto.2016.11] [Citation(s) in RCA: 598] [Impact Index Per Article: 74.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/20/2016] [Accepted: 02/23/2016] [Indexed: 12/14/2022]
Abstract
T cells can be genetically modified to target tumors through the expression of a chimeric antigen receptor (CAR). Most notably, CAR T cells have demonstrated clinical efficacy in hematologic malignancies with more modest responses when targeting solid tumors. However, CAR T cells also have the capacity to elicit expected and unexpected toxicities including: cytokine release syndrome, neurologic toxicity, “on target/off tumor” recognition, and anaphylaxis. Theoretical toxicities including clonal expansion secondary to insertional oncogenesis, graft versus host disease, and off-target antigen recognition have not been clinically evident. Abrogating toxicity has become a critical step in the successful application of this emerging technology. To this end, we review the reported and theoretical toxicities of CAR T cells and their management.
Collapse
|
28
|
Krüger M, Kötter S. Titin, a Central Mediator for Hypertrophic Signaling, Exercise-Induced Mechanosignaling and Skeletal Muscle Remodeling. Front Physiol 2016; 7:76. [PMID: 26973541 PMCID: PMC4771757 DOI: 10.3389/fphys.2016.00076] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/15/2016] [Indexed: 01/09/2023] Open
Abstract
Titin is a giant scaffold protein with multiple functions in striated muscle physiology. Due to the elastic I-band domains and the filament-like integration in the half-sarcomere titin is an important factor for sarcomere assembly and serves as an adaptable molecular spring that determines myofilament distensibility. Protein-interactions e.g., with muscle ankyrin repeat proteins or muscle LIM-protein link titin to hypertrophic signaling and via p62 and Muscle Ring Finger proteins to mechanisms that control protein quality control. This review summarizes our current knowledge on titin as a central node for exercise-induced mechanosignaling and remodeling and further highlights the pathophysiological implications.
Collapse
Affiliation(s)
- Martina Krüger
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf Düsseldorf, Germany
| | - Sebastian Kötter
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf Düsseldorf, Germany
| |
Collapse
|
29
|
Gramlich M, Pane LS, Zhou Q, Chen Z, Murgia M, Schötterl S, Goedel A, Metzger K, Brade T, Parrotta E, Schaller M, Gerull B, Thierfelder L, Aartsma-Rus A, Labeit S, Atherton JJ, McGaughran J, Harvey RP, Sinnecker D, Mann M, Laugwitz KL, Gawaz MP, Moretti A. Antisense-mediated exon skipping: a therapeutic strategy for titin-based dilated cardiomyopathy. EMBO Mol Med 2016; 7:562-76. [PMID: 25759365 PMCID: PMC4492817 DOI: 10.15252/emmm.201505047] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Frameshift mutations in the TTN gene encoding titin are a major cause for inherited forms of dilated cardiomyopathy (DCM), a heart disease characterized by ventricular dilatation, systolic dysfunction, and progressive heart failure. To date, there are no specific treatment options for DCM patients but heart transplantation. Here, we show the beneficial potential of reframing titin transcripts by antisense oligonucleotide (AON)-mediated exon skipping in human and murine models of DCM carrying a previously identified autosomal-dominant frameshift mutation in titin exon 326. Correction of TTN reading frame in patient-specific cardiomyocytes derived from induced pluripotent stem cells rescued defective myofibril assembly and stability and normalized the sarcomeric protein expression. AON treatment in Ttn knock-in mice improved sarcomere formation and contractile performance in homozygous embryos and prevented the development of the DCM phenotype in heterozygous animals. These results demonstrate that disruption of the titin reading frame due to a truncating DCM mutation can be restored by exon skipping in both patient cardiomyocytes in vitro and mouse heart in vivo, indicating RNA-based strategies as a potential treatment option for DCM.
Collapse
Affiliation(s)
- Michael Gramlich
- Department of Cardiology and Cardiovascular Diseases, Eberhard Karls University, Tübingen, Germany Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Luna Simona Pane
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany
| | - Qifeng Zhou
- Department of Cardiology and Cardiovascular Diseases, Eberhard Karls University, Tübingen, Germany
| | - Zhifen Chen
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany
| | - Marta Murgia
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Sonja Schötterl
- Department of Cardiology and Cardiovascular Diseases, Eberhard Karls University, Tübingen, Germany
| | - Alexander Goedel
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany
| | - Katja Metzger
- Department of Cardiology and Cardiovascular Diseases, Eberhard Karls University, Tübingen, Germany
| | - Thomas Brade
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany
| | - Elvira Parrotta
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany Department of Experimental and Clinical Medicine, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Martin Schaller
- Department of Dermatology, Eberhard Karls University, Tübingen, Germany
| | - Brenda Gerull
- Libin Cardiovascular Institute of Alberta and University of Calgary, Calgary, AB, Canada
| | | | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Siegfried Labeit
- Institute for Integrative Pathophysiology, Universitätsmedizin Mannheim, Mannheim, Germany
| | - John J Atherton
- Department of Cardiology, Royal Brisbane and Women's Hospital and University of Queensland School of Medicine, Brisbane, Australia
| | - Julie McGaughran
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia
| | - Richard P Harvey
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia St Vincent's Clinical School, University of New South Wales, Kensington, NSW, Australia
| | - Daniel Sinnecker
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Karl-Ludwig Laugwitz
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Meinrad Paul Gawaz
- Department of Cardiology and Cardiovascular Diseases, Eberhard Karls University, Tübingen, Germany
| | - Alessandra Moretti
- I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| |
Collapse
|
30
|
James J, Robbins J. Bringing It All Together: Bedside to Bench and Back Again. Circ Res 2015; 117:987-9. [PMID: 26635381 DOI: 10.1161/circresaha.115.307874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Jeanne James
- From the Department of Pediatrics, The Heart Institute, Cincinnati Children's Hospital Medical Center, OH
| | - Jeffrey Robbins
- From the Department of Pediatrics, The Heart Institute, Cincinnati Children's Hospital Medical Center, OH.
| |
Collapse
|
31
|
Identification of a Novel Mutation in the Titin Gene in a Chinese Family with Limb-Girdle Muscular Dystrophy 2J. Mol Neurobiol 2015; 53:5097-102. [DOI: 10.1007/s12035-015-9439-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/10/2015] [Indexed: 01/01/2023]
|
32
|
Shin SH, Huang M, Kim SH, Choi JY. Differential Protein Expression in Congenital and Acquired Cholesteatomas. PLoS One 2015; 10:e0137011. [PMID: 26335306 PMCID: PMC4559438 DOI: 10.1371/journal.pone.0137011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/11/2015] [Indexed: 11/23/2022] Open
Abstract
Congenital cholesteatomas are epithelial lesions that present as an epithelial pearl behind an intact eardrum. Congenital and acquired cholesteatomas progress quite differently from each other and progress patterns can provide clues about the unique origin and pathogenesis of the abnormality. However, the exact pathogenic mechanisms by which cholesteatomas develop remain unknown. In this study, key proteins that directly affect cholesteatoma pathogenesis are investigated with proteomics and immunohistochemistry. Congenital cholesteatoma matrices and retroauricular skin were harvested during surgery in 4 patients diagnosed with a congenital cholesteatoma. Tissue was also harvested from the retraction pocket in an additional 2 patients during middle ear surgery. We performed 2-dimensional (2D) electrophoresis to detect and analyze spots that are expressed only in congenital cholesteatoma and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) to separate proteins by molecular weight. Protein expression was confirmed by immunohistochemical staining. The image analysis of 2D electrophoresis showed that 4 congenital cholesteatoma samples had very similar protein expression patterns and that 127 spots were exclusively expressed in congenital cholesteatomas. Of these 127 spots, 10 major spots revealed the presence of titin, forkhead transcription activator homolog (FKH 5–3), plectin 1, keratin 10, and leucine zipper protein 5 by MALDI-TOF/MS analysis. Immunohistochemical staining showed that FKH 5–3 and titin were expressed in congenital cholesteatoma matrices, but not in acquired cholesteatomas. Our study shows that protein expression patterns are completely different in congenital cholesteatomas, acquired cholesteatomas, and skin. Moreover, non-epithelial proteins, including FKH 5–3 and titin, were unexpectedly expressed in congenital cholesteatoma tissue. Our data indicates that congenital cholesteatoma origins may differ from those of acquired cholesteatomas, which originate from retraction pocket epithelia.
Collapse
Affiliation(s)
- Seung-Ho Shin
- Department of Otorhinolaryngology–Head and Neck Surgery, School of Medicine, Ewha Womans University, Seoul, Korea
- Department of Medicine, Graduate School, Yonsei University, Seoul, Korea
| | - Mei Huang
- Research Center for Human Natural Defense System, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Huhn Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
- * E-mail: (JYC); (SHK)
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
- * E-mail: (JYC); (SHK)
| |
Collapse
|
33
|
Thornell LE, Carlsson L, Eriksson PO, Liu JX, Österlund C, Stål P, Pedrosa-Domellöf F. Fibre typing of intrafusal fibres. J Anat 2015; 227:136-56. [PMID: 26179023 PMCID: PMC4523317 DOI: 10.1111/joa.12338] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2015] [Indexed: 12/23/2022] Open
Abstract
The first descriptions of muscle spindles with intrafusal fibres containing striated myofibrils and nervous elements were given approximately 150 years ago. It took, however, another 100 years to establish the presence of two types of intrafusal muscle fibres: nuclear bag and nuclear chain fibres. The present paper highlights primarily the contribution of Robert Banks in fibre typing of intrafusal fibres: the confirmation of the principle of two types of nuclear bag fibres in mammalian spindles and the variation in occurrence of a dense M-band along the fibres. Furthermore, this paper summarizes how studies from the Umeå University group (Laboratory of Muscle Biology in the Department of Integrative Medical Biology) on fibre typing and the structure and composition of M-bands have contributed to the current understanding of muscle spindle complexity in adult humans as well as to muscle spindle development and effects of ageing. The variable molecular composition of the intrafusal sarcomeres with respect to myosin heavy chains and M-band proteins gives new perspectives on the role of the intrafusal myofibrils as stretch-activated sensors influencing tension/stiffness and signalling to nuclei.
Collapse
Affiliation(s)
- Lars-Eric Thornell
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Lena Carlsson
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Per-Olof Eriksson
- Department of Odontology, Clinical Oral Physiology, Umeå UniversityUmeå, Sweden
| | - Jing-Xia Liu
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Catharina Österlund
- Department of Odontology, Clinical Oral Physiology, Umeå UniversityUmeå, Sweden
| | - Per Stål
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Fatima Pedrosa-Domellöf
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå UniversityUmeå, Sweden
| |
Collapse
|