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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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2
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Lisin R, Balakin A, Mukhlynina E, Protsenko Y. Differences in Mechanical, Electrical and Calcium Transient Performance of the Isolated Right Atrial and Ventricular Myocardium of Guinea Pigs at Different Preloads (Lengths). Int J Mol Sci 2023; 24:15524. [PMID: 37958508 PMCID: PMC10650485 DOI: 10.3390/ijms242115524] [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: 09/29/2023] [Revised: 10/19/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023] Open
Abstract
There are only a few studies devoted to the comparative and simultaneous study of the mechanisms of the length-dependent regulation of atrial and ventricular contractility. Therefore, an isometric force-length protocol was applied to isolated guinea pig right atrial (RA) strips and ventricular (RV) trabeculae, with a simultaneous measurement of force (Frank-Starling mechanism) and Ca2+ transients (CaT) or transmembrane action potentials (AP). Over the entire length-range studied, the duration of isometric contraction, CaT and AP, were shorter in the RA myocardium than in the RV myocardium. The RA myocardium was stiffer than the RV myocardium. With the increasing length of the RA and RV myocardium, the amplitude and duration of isometric contraction and CaT increased, as well as the amplitude and area of the "CaT difference curves" (shown for the first time). However, the rates of the tension development and relaxation decreased. No contribution of AP duration to the heterometric regulation of isometric tension was found in either the RA or RV myocardium of the guinea pig. Changes in the degree of overlap of the contractile proteins of the guinea pig RA and RV myocardium mainly affect CaT kinetics but not AP duration.
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Affiliation(s)
| | - Alexandr Balakin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 106 Pervomayskaya Str., Yekaterinburg 620049, Russia; (R.L.); (E.M.); (Y.P.)
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3
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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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5
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Kobirumaki-Shimozawa F, Shimozawa T, Oyama K, Baba S, Li J, Nakanishi T, Terui T, Louch WE, Ishiwata S, Fukuda N. Synchrony of sarcomeric movement regulates left ventricular pump function in the in vivo beating mouse heart. J Gen Physiol 2021; 153:212675. [PMID: 34605861 PMCID: PMC8493835 DOI: 10.1085/jgp.202012860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
Sarcomeric contraction in cardiomyocytes serves as the basis for the heart's pump functions. It has generally been considered that in cardiac muscle as well as in skeletal muscle, sarcomeres equally contribute to myofibrillar dynamics in myocytes at varying loads by producing similar levels of active and passive force. In the present study, we expressed α-actinin-AcGFP in Z-disks to analyze dynamic behaviors of sequentially connected individual sarcomeres along a myofibril in a left ventricular (LV) myocyte of the in vivo beating mouse heart. To quantify the magnitude of the contribution of individual sarcomeres to myofibrillar dynamics, we introduced the novel parameter "contribution index" (CI) to measure the synchrony in movements between a sarcomere and a myofibril (from -1 [complete asynchrony] to 1 [complete synchrony]). First, CI varied markedly between sarcomeres, with an average value of ∼0.3 during normal systole. Second, when the movements between adjacent sarcomeres were asynchronous (CI < 0), a sarcomere and the ones next to the adjacent sarcomeres and farther away moved in synchrony (CI > 0) along a myofibril. Third, when difference in LV pressure in diastole and systole (ΔLVP) was lowered to <10 mm Hg, diastolic sarcomere length increased. Under depressed conditions, the movements between adjacent sarcomeres were in marked asynchrony (CI, -0.3 to -0.4), and, as a result, average CI was linearly decreased in association with a decrease in ΔLVP. These findings suggest that in the left ventricle of the in vivo beating mouse heart, (1) sarcomeres heterogeneously contribute to myofibrillar dynamics due to an imbalance of active and passive force between neighboring sarcomeres, (2) the force imbalance is pronounced under depressed conditions coupled with a marked increase in passive force and the ensuing tug-of-war between sarcomeres, and (3) sarcomere synchrony via the distal intersarcomere interaction regulates the heart's pump function in coordination with myofibrillar contractility.
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Affiliation(s)
| | - Togo Shimozawa
- Technical Division, School of Science, The University of Tokyo, Tokyo, Japan
| | - Kotaro Oyama
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan.,Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Gunma, Japan
| | - Shunsuke Baba
- Department of Pediatrics, The Jikei University School of Medicine, Tokyo, Japan
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Tomohiro Nakanishi
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takako Terui
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Norio Fukuda
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
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6
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Adewale AO, Ahn YH. Titin N2A Domain and Its Interactions at the Sarcomere. Int J Mol Sci 2021; 22:ijms22147563. [PMID: 34299183 PMCID: PMC8305307 DOI: 10.3390/ijms22147563] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/16/2022] Open
Abstract
Titin is a giant protein in the sarcomere that plays an essential role in muscle contraction with actin and myosin filaments. However, its utility goes beyond mechanical functions, extending to versatile and complex roles in sarcomere organization and maintenance, passive force, mechanosensing, and signaling. Titin’s multiple functions are in part attributed to its large size and modular structures that interact with a myriad of protein partners. Among titin’s domains, the N2A element is one of titin’s unique segments that contributes to titin’s functions in compliance, contraction, structural stability, and signaling via protein–protein interactions with actin filament, chaperones, stress-sensing proteins, and proteases. Considering the significance of N2A, this review highlights structural conformations of N2A, its predisposition for protein–protein interactions, and its multiple interacting protein partners that allow the modulation of titin’s biological effects. Lastly, the nature of N2A for interactions with chaperones and proteases is included, presenting it as an important node that impacts titin’s structural and functional integrity.
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7
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Banga S, Heinze-Milne SD, Godin J, Howlett SE. Signs of diastolic dysfunction are graded by serum testosterone levels in aging C57BL/6 male mice. Mech Ageing Dev 2021; 198:111523. [PMID: 34166687 DOI: 10.1016/j.mad.2021.111523] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/01/2021] [Accepted: 06/17/2021] [Indexed: 01/08/2023]
Abstract
We investigated whether maladaptive, age-associated changes in heart structure and function were linked to circulating testosterone levels. Male C57BL/6 mice had a gonadectomy (GDX) or sham surgery at 4 weeks and effects of GDX on the heart were examined with echocardiography. Serum testosterone was measured with ELISA. Left ventricular (LV) mass increased with age but was smaller in GDX mice than sham at 18 months (144.0 ± 8.7 vs 118.2 ± 11.9 mg; p = 0.009). The isovolumic relaxation time (IVRT) declined with age but was prolonged in GDX mice at 18 months (10.5 ± 0.8 vs 12.5 ± 0.5 msec, p = 0.008). Ejection fraction did not change with age or GDX, but E/A ratios were lower in GDX mice than controls at 18 months (1.6 ± 0.2 vs 1.3 ± 0.1, p = 0.021). When links between serum testosterone and cardiac parameters were examined longitudinally in 18-24-month-old mice, LV mass declined with decreasing testosterone (β = 37.70, p = 0.016), however IVRT increased as testosterone decreased (β=-2.69, p = 0.036). Since longer IVRT and lower E/A ratios are signs of diastolic dysfunction, low circulating testosterone may promote or exacerbate diastolic dysfunction in older males. These findings suggest that lower testosterone directly modifies heart structure and function to promote maladaptive remodeling and diastolic dysfunction in the aging heart.
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Affiliation(s)
- Shubham Banga
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada.
| | | | - Judith Godin
- Geriatric Medicine Research, Division of Geriatric Medicine, Nova Scotia Health Authority and Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Susan E Howlett
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada; Department of Medicine (Geriatric Medicine), Dalhousie University, Halifax, NS, Canada.
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8
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Münch J, Abdelilah-Seyfried S. Sensing and Responding of Cardiomyocytes to Changes of Tissue Stiffness in the Diseased Heart. Front Cell Dev Biol 2021; 9:642840. [PMID: 33718383 PMCID: PMC7952448 DOI: 10.3389/fcell.2021.642840] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/09/2021] [Indexed: 12/20/2022] Open
Abstract
Cardiomyocytes are permanently exposed to mechanical stimulation due to cardiac contractility. Passive myocardial stiffness is a crucial factor, which defines the physiological ventricular compliance and volume of diastolic filling with blood. Heart diseases often present with increased myocardial stiffness, for instance when fibrotic changes modify the composition of the cardiac extracellular matrix (ECM). Consequently, the ventricle loses its compliance, and the diastolic blood volume is reduced. Recent advances in the field of cardiac mechanobiology revealed that disease-related environmental stiffness changes cause severe alterations in cardiomyocyte cellular behavior and function. Here, we review the molecular mechanotransduction pathways that enable cardiomyocytes to sense stiffness changes and translate those into an altered gene expression. We will also summarize current knowledge about when myocardial stiffness increases in the diseased heart. Sophisticated in vitro studies revealed functional changes, when cardiomyocytes faced a stiffer matrix. Finally, we will highlight recent studies that described modulations of cardiac stiffness and thus myocardial performance in vivo. Mechanobiology research is just at the cusp of systematic investigations related to mechanical changes in the diseased heart but what is known already makes way for new therapeutic approaches in regenerative biology.
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Affiliation(s)
- Juliane Münch
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Salim Abdelilah-Seyfried
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.,Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
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9
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Li M, Wu J, Hu G, Song Y, Shen J, Xin J, Li Z, Liu W, Dong E, Xu M, Zhang Y, Xiao H. Pathological matrix stiffness promotes cardiac fibroblast differentiation through the POU2F1 signaling pathway. SCIENCE CHINA. LIFE SCIENCES 2021; 64:242-254. [PMID: 32617828 DOI: 10.1007/s11427-019-1747-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/21/2020] [Indexed: 12/13/2022]
Abstract
Cardiac fibroblast (CF) differentiation into myofibroblasts is a crucial cause of cardiac fibrosis, which increases in the extracellular matrix (ECM) stiffness. The increased stiffness further promotes CF differentiation and fibrosis. However, the molecular mechanism is still unclear. We used bioinformatics analysis to find new candidates that regulate the genes involved in stiffness-induced CF differentiation, and found that there were binding sites for the POU-domain transcription factor, POU2F1 (also known as Oct-1), in the promoters of 50 differentially expressed genes (DEGs) in CFs on the stiffer substrate. Immunofluorescent staining and Western blotting revealed that pathological stiffness upregulated POU2F1 expression and increased CF differentiation on polyacrylamide hydrogel substrates and in mouse myocardial infarction tissue. A chromatin immunoprecipitation assay showed that POU2F1 bound to the promoters of fibrosis repressors IL1R2, CD69, and TGIF2. The expression of these fibrosis repressors was inhibited on pathological substrate stiffness. Knockdown of POU2F1 upregulated these repressors and attenuated CF differentiation on pathological substrate stiffness (35 kPa). Whereas, overexpression of POU2F1 downregulated these repressors and enhanced CF differentiation. In conclusion, pathological stiffness upregulates the transcription factor POU2F1 to promote CF differentiation by inhibiting fibrosis repressors. Our work elucidated the crosstalk between CF differentiation and the ECM and provided a potential target for cardiac fibrosis treatment.
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Affiliation(s)
- Mingzhe Li
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Jimin Wu
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Guomin Hu
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Yao Song
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Jing Shen
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Junzhou Xin
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Zijian Li
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Wei Liu
- Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Erdan Dong
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
- Institute of Cardiovascular Sciences, Health Science Center, Peking University, Beijing, 100191, China
| | - Ming Xu
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China
| | - Youyi Zhang
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China.
| | - Han Xiao
- Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital; NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education; Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China.
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10
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Lee EJ, Jang HC, Koo KH, Kim HY, Lim JY. Mechanical Properties of Single Muscle Fibers: Understanding Poor Muscle Quality in Older Adults with Diabetes. Ann Geriatr Med Res 2020; 24:267-273. [PMID: 33389973 PMCID: PMC7781968 DOI: 10.4235/agmr.20.0078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/21/2020] [Indexed: 12/25/2022] Open
Abstract
Background While aging causes muscle weakness, type 2 diabetes mellitus (T2DM) is also considered a high-risk factor for the induction of skeletal muscle weakness. Previous studies have reported increased collagen content in insulin-resistant skeletal muscles. Here, we studied the mechanical properties of aged skeletal muscle in patients with T2DM to investigate whether aged skeletal muscles with T2DM induce higher passive tension due to the abundance of extracellular matrix (ECM) inside or outside of the muscle fibers. Methods Samples from the gluteus maximus muscles of older adults with diabetes (T2DM) and non-diabetic (non-DM) older adults who underwent elective orthopedic surgery were collected. Permeabilized single muscle fibers from these samples were used to identify their mechanical properties. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to quantify titin and fiber type distributions in these samples. Results We confirmed a significant predominance of type I fiber ratio in both T2DM and non-DM aged muscles. While the average cross-sectional area and maximal active tension of the single fibers were smaller in the T2DM group than those in the non-DM group, the difference was not statistically significant. T2DM subjects showed significantly greater passive tension and lower titin-/ECM-based passive tension ratios than those in non-DM subjects, which indicated that more ECM but less titin contributed to the total passive tension. Conclusion Based on our findings, we concluded that T2DM may cause increased passive stiffness of single skeletal muscle fibers in older adults because of an excessive accumulation of ECM in and around single muscle fibers due to increased insulin resistance.
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Affiliation(s)
- Eun-Jeong Lee
- Department of Kinesiology, School of Health and Human Science, Concordia University Irvine, Irvine, CA, USA.,Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Hak Chul Jang
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Kyung-Hoi Koo
- Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Hye-Young Kim
- Division of Liberal Arts and Science, Korea National Sport University, Seoul, Korea
| | - Jae-Young Lim
- Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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Abstract
Muscle stiffness, muscle elasticity and explosive strength are the main components of athletes' performance and they show a sex-based as well as ethnicity variation. Muscle stiffness is thought to be one of the risk factors associated with sports injuries and is less common in females than in males. These observations may be explained by circulating levels of sex hormones and their specific receptors. It has been shown that higher levels of estrogen are associated with lower muscle stiffness responsible for suppression of collagen synthesis. It is thought that these properties, at least in part, depend on genetic factors. Particularly, the gene encoding estrogen receptor 1 (ESR1) is one of the candidates that may be associated with muscle stiffness. Muscle elasticity increases with aging and there is evidence suggesting that titin (encoded by the TTN gene), a protein that is expressed in cardiac and skeletal muscles, is one of the factors responsible for elastic properties of the muscles. Mutations in the TTN gene result in some types of muscular dystrophy or cardiomyopathy. In this context, TTN may be regarded as a promising candidate for studying the elastic properties of muscles in athletes. The physiological background of explosive strength depends not only on the muscle architecture and muscle fiber composition, but also on the central nervous system and functionality of neuromuscular units. These properties are, at least partly, genetically determined. In this context, the ACTN3 gene code for α-actinin 3 has been widely researched.
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12
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van der Pijl RJ, Hudson B, Granzier-Nakajima T, Li F, Knottnerus AM, Smith J, Chung CS, Gotthardt M, Granzier HL, Ottenheijm CAC. Deleting Titin's C-Terminal PEVK Exons Increases Passive Stiffness, Alters Splicing, and Induces Cross-Sectional and Longitudinal Hypertrophy in Skeletal Muscle. Front Physiol 2020; 11:494. [PMID: 32547410 PMCID: PMC7274174 DOI: 10.3389/fphys.2020.00494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022] Open
Abstract
The Proline, Glutamate, Valine and Lysine-rich (PEVK) region of titin constitutes an entropic spring that provides passive tension to striated muscle. To study the functional and structural repercussions of a small reduction in the size of the PEVK region, we investigated skeletal muscles of a mouse with the constitutively expressed C-terminal PEVK exons 219-225 deleted, the TtnΔ219-225 model (MGI: TtnTM 2.1Mgot ). Based on this deletion, passive tension in skeletal muscle was predicted to be increased by ∼17% (sarcomere length 3.0 μm). In contrast, measured passive tension (sarcomere length 3.0 μm) in both soleus and EDL muscles was increased 53 ± 11% and 62 ± 4%, respectively. This unexpected increase was due to changes in titin, not to alterations in the extracellular matrix, and is likely caused by co-expression of two titin isoforms in TtnΔ219-225 muscles: a larger isoform that represents the TtnΔ219-225 N2A titin and a smaller isoform, referred to as N2A2. N2A2 represents a splicing adaption with reduced expression of spring element exons, as determined by titin exon microarray analysis. Maximal tetanic tension was increased in TtnΔ219-225 soleus muscle (WT 240 ± 9; TtnΔ219-225 276 ± 17 mN/mm2), but was reduced in EDL muscle (WT 315 ± 9; TtnΔ219-225 280 ± 14 mN/mm2). The changes in active tension coincided with a switch toward slow fiber types and, unexpectedly, faster kinetics of tension generation and relaxation. Functional overload (FO; ablation) and hindlimb suspension (HS; unloading) experiments were also conducted. TtnΔ219-225 mice showed increases in both longitudinal hypertrophy (increased number of sarcomeres in series) and cross-sectional hypertrophy (increased number of sarcomeres in parallel) in response to FO and attenuated cross-sectional atrophy in response to HS. In summary, slow- and fast-twitch muscles in a mouse model devoid of titin's PEVK exons 219-225 have high passive tension, due in part to alterations elsewhere in splicing of titin's spring region, increased kinetics of tension generation and relaxation, and altered trophic responses to both functional overload and unloading. This implicates titin's C-terminal PEVK region in regulating passive and active muscle mechanics and muscle plasticity.
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Affiliation(s)
- Robbert J van der Pijl
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States.,Department of Physiology, Amsterdam UMC, Amsterdam, Netherlands
| | - Brian Hudson
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States
| | | | - Frank Li
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States
| | - Anne M Knottnerus
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States
| | - John Smith
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States
| | - Charles S Chung
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States.,Department of Physiology, Wayne State University, Detroit, MI, United States
| | - Michael Gotthardt
- Max-Delbruck-Center for Molecular Medicine, Berlin, Germany.,Cardiology, Virchow Klinikum, Charité University Medicine, Berlin, Germany
| | - Henk L Granzier
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States
| | - Coen A C Ottenheijm
- Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States.,Department of Physiology, Amsterdam UMC, Amsterdam, Netherlands
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13
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Chung CS, Hiske MA, Chadha A, Mueller PJ. Compliant Titin Isoform Content Is Reduced in Left Ventricles of Sedentary Versus Active Rats. Front Physiol 2020; 11:15. [PMID: 32116740 PMCID: PMC7025574 DOI: 10.3389/fphys.2020.00015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/13/2020] [Indexed: 11/30/2022] Open
Abstract
A sedentary lifestyle is associated with increased cardiovascular risk factors and reduced cardiac compliance when compared to a lifestyle that includes exercise training. Exercise training increases cardiac compliance in humans, but the mechanisms underlying this improvement are unknown. A major determinant of cardiac compliance is the compliance of the giant elastic protein titin. Experimentally reducing titin compliance in animal models reduces exercise tolerance, but it is not known whether sedentary versus chronic exercise conditions cause differences in titin isoform content. We hypothesized that sedentary conditions would be associated with a reduction in the content of the longer, more compliant N2BA isoform relative to the stiffer N2B isoform (yielding a reduced N2BA:N2B ratio) compared to age-matched exercising controls. We obtained left ventricles from 16-week old rats housed for 12 weeks in standard (sedentary) or voluntary running wheel (exercised) housing. The N2BA:N2B ratio was decreased in the hearts of sedentary versus active rats (p = 0.041). Gene expression of a titin mRNA splicing factor, RNA Binding Motif 20 protein (RBM20), correlated negatively with N2BA:N2B ratios (p = 0.006, r = -0.449), but was not different between groups, suggesting that RBM20 may be regulated post-transcriptionally. Total phosphorylation of cardiac titin was not different between the active and sedentary groups. This study is the first to demonstrate that sedentary rats exhibit reduced cardiac titin N2BA:N2B isoform ratios, which implies reduced cardiac compliance. These data suggest that a lack of exercise (running wheel) reduces cardiac compliance and that exercise itself increases cardiac compliance.
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14
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Oláh A, Ruppert M, Orbán TI, Apáti Á, Sarkadi B, Merkely B, Radovits T. Hemodynamic characterization of a transgenic rat strain stably expressing the calcium sensor protein GCaMP2. Am J Physiol Heart Circ Physiol 2019; 316:H1224-H1228. [DOI: 10.1152/ajpheart.00074.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A novel transgenic rat strain has recently been generated that stably expresses the genetically engineered calcium sensor protein GCaMP2 in different cell types, including cardiomyocytes, to investigate calcium homeostasis. To investigate whether the expression of the GCaMP2 protein itself affects cardiac function, in the present work we aimed at characterizing in vivo hemodynamics in the GCaMP2 transgenic rat strain. GCaMP2 transgenic rats and age-matched Sprague-Dawley control animals were investigated. In vivo hemodynamic characterization was performed by left ventricular (LV) pressure-volume analysis. Postmortem heart weight data showed cardiac hypertrophy in the GCaMP2 group (heart-weight-to-tibial-length ratio: 0.26 ± 0.01 GCaMP2 vs. 0.23 ± 0.01 g/cm Co, P < 0.05). We detected elevated mean arterial pressure and increased total peripheral resistance in transgenic rats. GCaMP2 transgenesis was associated with prolonged contraction and relaxation. LV systolic function was not altered in transgenic rats, as indicated by conventional parameters and load-independent, sensitive indices. We found a marked deterioration of LV active relaxation in GCaMP2 animals (τ: 16.8 ± 0.7 GCaMP2 vs. 12.2 ± 0.3 ms Co, P < 0.001). Our data indicated myocardial hypertrophy, arterial hypertension, and impaired LV active relaxation along with unchanged systolic performance in the heart of transgenic rats expressing the GCaMP2 fluorescent calcium sensor protein. Special caution should be taken when using transgenic models in cardiovascular studies. NEW & NOTEWORTHY Genetically encoded Ca2+-sensors, like GCaMP2, are important tools to reveal molecular mechanisms for Ca2+-sensing. We provided left ventricular hemodynamic characterization of GCaMP2 transgenic rats and found increased afterload, cardiac hypertrophy, and prolonged left ventricular relaxation, along with unaltered systolic function and contractility. Special caution should be taken when using this rodent model in cardiovascular pharmacological and toxicological studies.
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Affiliation(s)
- Attila Oláh
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Mihály Ruppert
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Tamás István Orbán
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ágota Apáti
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Balázs Sarkadi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Béla Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Tamás Radovits
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
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15
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Kellermayer D, Smith JE, Granzier H. Titin mutations and muscle disease. Pflugers Arch 2019; 471:673-682. [PMID: 30919088 DOI: 10.1007/s00424-019-02272-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022]
Abstract
The introduction of next-generation sequencing technology has revealed that mutations in the gene that encodes titin (TTN) are linked to multiple skeletal and cardiac myopathies. The most prominent of these myopathies is dilated cardiomyopathy (DCM). Over 60 genes are linked to the etiology of DCM, but by far, the leading cause of DCM is mutations in TTN with truncating variants in TTN (TTNtvs) associated with familial DCM in ∼ 20% of the cases. Titin is a large (3-4 MDa) and abundant protein that forms the third myofilament type of striated muscle where it spans half the sarcomere, from the Z-disk to the M-line. The underlying mechanisms by which titin mutations induce disease are poorly understood and targeted therapies are not available. Here, we review what is known about TTN mutations in muscle disease, with a major focus on DCM. We highlight that exon skipping might provide a possible therapeutic avenue to address diseases that arise from TTNtvs.
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Affiliation(s)
- Dalma Kellermayer
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA.,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA
| | - John E Smith
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA.,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA. .,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA.
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16
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Slater RE, Strom JG, Methawasin M, Liss M, Gotthardt M, Sweitzer N, Granzier HL. Metformin improves diastolic function in an HFpEF-like mouse model by increasing titin compliance. J Gen Physiol 2018; 151:42-52. [PMID: 30567709 PMCID: PMC6314384 DOI: 10.1085/jgp.201812259] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 11/14/2018] [Indexed: 12/20/2022] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) is a syndrome characterized by increased diastolic stiffness, for which effective therapies are lacking. Slater et al. show that metformin lowers titin-based passive stiffness in an HFpEF mouse model and may therefore be of therapeutic benefit. Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome characterized by a preserved ejection fraction but increased diastolic stiffness and abnormalities of filling. Although the prevalence of HFpEF is high and continues to rise, no effective therapies exist; however, the diabetic drug metformin has been associated with improved diastolic function in diabetic patients. Here we determine the therapeutic potential of metformin for improving diastolic function in a mouse model with HFpEF-like symptoms. We combine transverse aortic constriction (TAC) surgery with deoxycorticosterone acetate (DOCA) supplementation to obtain a mouse model with increased diastolic stiffness and exercise intolerance. Echocardiography and pressure–volume analysis reveal that providing metformin to TAC/DOCA mice improves diastolic function in the left ventricular (LV) chamber. Muscle mechanics show that metformin lowers passive stiffness of the LV wall muscle. Concomitant with this improvement in diastolic function, metformin-treated TAC/DOCA mice also demonstrate preserved exercise capacity. No metformin effects are seen in sham operated mice. Extraction experiments on skinned ventricular muscle strips show that the metformin-induced reduction of passive stiffness in TAC/DOCA mice is due to an increase in titin compliance. Using phospho-site-specific antibodies, we assay the phosphorylation of titin’s PEVK and N2B spring elements. Metformin-treated mice have unaltered PEVK phosphorylation but increased phosphorylation of PKA sites in the N2B element, a change which has previously been shown to lower titin’s stiffness. Consistent with this result, experiments with a mouse model deficient in the N2B element reveal that the beneficial effect of metformin on LV chamber and muscle stiffness requires the presence of the N2B element. We conclude that metformin offers therapeutic benefit during HFpEF by lowering titin-based passive stiffness.
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Affiliation(s)
- Rebecca E Slater
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Joshua G Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Martin Liss
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.,German Center for Cardiovascular Research, Partner Site Berlin, Berlin, Germany
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.,German Center for Cardiovascular Research, Partner Site Berlin, Berlin, Germany
| | - Nancy Sweitzer
- Sarver Heart Center, College of Medicine, University of Arizona, Tucson, AZ
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ .,Sarver Heart Center, College of Medicine, University of Arizona, Tucson, AZ
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17
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Brynnel A, Hernandez Y, Kiss B, Lindqvist J, Adler M, Kolb J, van der Pijl R, Gohlke J, Strom J, Smith J, Ottenheijm C, Granzier HL. Downsizing the molecular spring of the giant protein titin reveals that skeletal muscle titin determines passive stiffness and drives longitudinal hypertrophy. eLife 2018; 7:40532. [PMID: 30565562 PMCID: PMC6300359 DOI: 10.7554/elife.40532] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/26/2018] [Indexed: 12/25/2022] Open
Abstract
Titin, the largest protein known, forms an elastic myofilament in the striated muscle sarcomere. To establish titin’s contribution to skeletal muscle passive stiffness, relative to that of the extracellular matrix, a mouse model was created in which titin’s molecular spring region was shortened by deleting 47 exons, the TtnΔ112-158 model. RNA sequencing and super-resolution microscopy predicts a much stiffer titin molecule. Mechanical studies with this novel mouse model support that titin is the main determinant of skeletal muscle passive stiffness. Unexpectedly, the in vivo sarcomere length working range was shifted to shorter lengths in TtnΔ112-158 mice, due to a ~ 30% increase in the number of sarcomeres in series (longitudinal hypertrophy). The expected effect of this shift on active force generation was minimized through a shortening of thin filaments that was discovered in TtnΔ112-158 mice. Thus, skeletal muscle titin is the dominant determinant of physiological passive stiffness and drives longitudinal hypertrophy. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Ambjorn Brynnel
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Yaeren Hernandez
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Balazs Kiss
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Johan Lindqvist
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Maya Adler
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Justin Kolb
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Robbert van der Pijl
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Jochen Gohlke
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - John Smith
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Coen Ottenheijm
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, United States
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18
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Li KL, Methawasin M, Tanner BCW, Granzier HL, Solaro RJ, Dong WJ. Sarcomere length-dependent effects on Ca 2+-troponin regulation in myocardium expressing compliant titin. J Gen Physiol 2018; 151:30-41. [PMID: 30523116 PMCID: PMC6314383 DOI: 10.1085/jgp.201812218] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/01/2018] [Indexed: 11/20/2022] Open
Abstract
Increases in sarcomere length cause enhanced force generation in cardiomyocytes by an unknown mechanism. Li et al. reveal that titin-based passive tension contributes to length-dependent activation of myofilaments and that tightly bound myosin–actin cross-bridges are associated with this effect. Cardiac performance is tightly regulated at the cardiomyocyte level by sarcomere length, such that increases in sarcomere length lead to sharply enhanced force generation at the same Ca2+ concentration. Length-dependent activation of myofilaments involves dynamic and complex interactions between a multitude of thick- and thin-filament components. Among these components, troponin, myosin, and the giant protein titin are likely to be key players, but the mechanism by which these proteins are functionally linked has been elusive. Here, we investigate this link in the mouse myocardium using in situ FRET techniques. Our objective was to monitor how length-dependent Ca2+-induced conformational changes in the N domain of cardiac troponin C (cTnC) are modulated by myosin–actin cross-bridge (XB) interactions and increased titin compliance. We reconstitute FRET donor- and acceptor-modified cTnC(13C/51C)AEDANS-DDPM into chemically skinned myocardial fibers from wild-type and RBM20-deletion mice. The Ca2+-induced conformational changes in cTnC are quantified and characterized using time-resolved FRET measurements as XB state and sarcomere length are varied. The RBM20-deficient mouse expresses a more compliant N2BA titin isoform, leading to reduced passive tension in the myocardium. This provides a molecular tool to investigate how altered titin-based passive tension affects Ca2+-troponin regulation in response to mechanical stretch. In wild-type myocardium, we observe a direct association of sarcomere length–dependent enhancement of troponin regulation with both Ca2+ activation and strongly bound XB states. In comparison, measurements from titin RBM20-deficient animals show blunted sarcomere length–dependent effects. These results suggest that titin-based passive tension contributes to sarcomere length–dependent Ca2+-troponin regulation. We also conclude that strong XB binding plays an important role in linking the modulatory effect of titin compliance to Ca2+-troponin regulation of the myocardium.
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Affiliation(s)
- King-Lun Li
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Bertrand C W Tanner
- Integrative Physiology and Neuroscience, Washington State University, Pullman, WA
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - R John Solaro
- The Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Wen-Ji Dong
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA .,Integrative Physiology and Neuroscience, Washington State University, Pullman, WA
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19
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Greenberg MJ, Daily NJ, Wang A, Conway MK, Wakatsuki T. Genetic and Tissue Engineering Approaches to Modeling the Mechanics of Human Heart Failure for Drug Discovery. Front Cardiovasc Med 2018; 5:120. [PMID: 30283789 PMCID: PMC6156537 DOI: 10.3389/fcvm.2018.00120] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022] Open
Abstract
Heart failure is the leading cause of death in the western world and as such, there is a great need for new therapies. Heart failure has a variable presentation in patients and a complex etiology; however, it is fundamentally a condition that affects the mechanics of cardiac contraction, preventing the heart from generating sufficient cardiac output under normal operating pressures. One of the major issues hindering the development of new therapies has been difficulties in developing appropriate in vitro model systems of human heart failure that recapitulate the essential changes in cardiac mechanics seen in the disease. Recent advances in stem cell technologies, genetic engineering, and tissue engineering have the potential to revolutionize our ability to model and study heart failure in vitro. Here, we review how these technologies are being applied to develop personalized models of heart failure and discover novel therapeutics.
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Affiliation(s)
- Michael J Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, United States
| | | | - Ann Wang
- InvivoSciences Inc., Madison, WI, United States
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20
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Liss M, Radke MH, Eckhard J, Neuenschwander M, Dauksaite V, von Kries JP, Gotthardt M. Drug discovery with an RBM20 dependent titin splice reporter identifies cardenolides as lead structures to improve cardiac filling. PLoS One 2018; 13:e0198492. [PMID: 29889873 PMCID: PMC5995442 DOI: 10.1371/journal.pone.0198492] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/20/2018] [Indexed: 02/07/2023] Open
Abstract
Diastolic dysfunction is increasingly prevalent in our ageing society and an important contributor to heart failure. The giant protein titin could serve as a therapeutic target, as its elastic properties are a main determinant of cardiac filling in diastole. This study aimed to develop a high throughput pharmacological screen to identify small molecules that affect titin isoform expression through differential inclusion of exons encoding the elastic PEVK domains. We used a dual luciferase splice reporter assay that builds on the titin splice factor RBM20 to screen ~34,000 small molecules and identified several compounds that inhibit the exclusion of PEVK exons. These compounds belong to the class of cardenolides and affect RBM20 dependent titin exon exclusion but did not affect RBFOX1 mediated splicing of FMNL3. We provide evidence that cardenolides do not bind to the RNA interacting domain of RBM20, but reduce RBM20 protein levels and alter transcription of select splicing factors that interact with RBM20. Cardenolides affect titin isoform expression. Understanding their mode of action and harnessing the splice effects through chemical modifications that suppress the effects on ion homeostasis and more selectively affect cardiac splicing has the potential to improve cardiac filling and thus help patients with diastolic heart failure, for which currently no targeted therapy exists.
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Affiliation(s)
- Martin Liss
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Michael H. Radke
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Jamina Eckhard
- Screening Unit, Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | | | - Vita Dauksaite
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | | | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- * E-mail:
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21
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Røe ÅT, Aronsen JM, Skårdal K, Hamdani N, Linke WA, Danielsen HE, Sejersted OM, Sjaastad I, Louch WE. Increased passive stiffness promotes diastolic dysfunction despite improved Ca2+ handling during left ventricular concentric hypertrophy. Cardiovasc Res 2018; 113:1161-1172. [PMID: 28472418 PMCID: PMC5852536 DOI: 10.1093/cvr/cvx087] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/03/2017] [Indexed: 02/06/2023] Open
Abstract
Aims Concentric hypertrophy following pressure-overload is linked to preserved systolic function but impaired diastolic function, and is an important substrate for heart failure with preserved ejection fraction. While increased passive stiffness of the myocardium is a suggested mechanism underlying diastolic dysfunction in these hearts, the contribution of active diastolic Ca2+ cycling in cardiomyocytes remains unclear. In this study, we sought to dissect contributions of passive and active mechanisms to diastolic dysfunction in the concentrically hypertrophied heart following pressure-overload. Methods and results Rats were subjected to aortic banding (AB), and experiments were performed 6 weeks after surgery using sham-operated rats as controls. In vivo ejection fraction and fractional shortening were normal, confirming preservation of systolic function. Left ventricular concentric hypertrophy and diastolic dysfunction following AB were indicated by thickening of the ventricular wall, reduced peak early diastolic tissue velocity, and higher E/e' values. Slowed relaxation was also observed in left ventricular muscle strips isolated from AB hearts, during both isometric and isotonic stimulation, and accompanied by increases in passive tension, viscosity, and extracellular collagen. An altered titin phosphorylation profile was observed with hypophosphorylation of the phosphosites S4080 and S3991 sites within the N2Bus, and S12884 within the PEVK region. Increased titin-based stiffness was confirmed by salt-extraction experiments. In contrast, isolated, unloaded cardiomyocytes exhibited accelerated relaxation in AB compared to sham, and less contracture at high pacing frequencies. Parallel enhancement of diastolic Ca2+ handling was observed, with augmented NCX and SERCA2 activity and lowered resting cytosolic [Ca2+]. Conclusion In the hypertrophied heart with preserved systolic function, in vivo diastolic dysfunction develops as cardiac fibrosis and alterations in titin phosphorylation compromise left ventricular compliance, and despite compensatory changes in cardiomyocyte Ca2+ homeostasis.
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MESH Headings
- Adaptation, Physiological
- Animals
- Aorta/physiopathology
- Aorta/surgery
- Arterial Pressure
- Calcium/metabolism
- Calcium Signaling
- Collagen/metabolism
- Compliance
- Connectin/metabolism
- Constriction
- Diastole
- Disease Models, Animal
- Fibrosis
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Isolated Heart Preparation
- Male
- Myocardium/metabolism
- Myocardium/pathology
- Phosphorylation
- Rats, Wistar
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Sodium-Calcium Exchanger/metabolism
- Systole
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
- Ventricular Remodeling
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Affiliation(s)
- Åsmund T. Røe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, Kirkeveien 166, NO-0407 Oslo, Norway
- Corresponding author. Tel: +47 23 01 68 00; fax: +47 23 01 67 99, E-mail:
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, Kirkeveien 166, NO-0407 Oslo, Norway
- Bjørknes College, Oslo, Norway
| | - Kristine Skårdal
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, Kirkeveien 166, NO-0407 Oslo, Norway
| | - Nazha Hamdani
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | - Wolfgang A. Linke
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | - Håvard E. Danielsen
- Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway
- Nuffield Division of Clinical Laboratory Sciences, University of Oxford, Oxford, UK
| | - Ole M. Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, Kirkeveien 166, NO-0407 Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, Kirkeveien 166, NO-0407 Oslo, Norway
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, Kirkeveien 166, NO-0407 Oslo, Norway
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22
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Abstract
PURPOSE OF REVIEW Hypertension is the most prevalent risk factor in heart failure with preserved ejection fraction (HFpEF) and plays a key role in the disease. The continued lack of effective therapies to improve outcomes in HFpEF underscores the knowledge gaps regarding the pathophysiology of HFpEF. This review builds on fundamental concepts in pressure overload-induced left ventricular modeling, and summarizes recent knowledge gained regarding the mechanisms underlying the transition from hypertensive heart disease to HFpEF. RECENT FINDINGS The pathophysiology of hypertensive HFpEF extends beyond the development of left ventricular hypertrophy and diastolic dysfunction to myocardial contractile dysfunction, beyond left atrial structural dilatation to left atrial functional decline, beyond macrovascular stiffening to microvascular dysfunction, beyond central cardiac triggers to systemic endothelial inflammation, beyond fibrosis to titin changes, and beyond collagen deposition to qualitative changes in collagen. The central paradigm involves a systemic proinflammatory state triggering a downstream cascade of cardiac microvascular endothelial activation, oxidative stress, and abnormal myocardial cyclic guanosine monophosphate signaling, leading to microvascular rarefaction, chronic ischemia, fibrosis and progression to HFpEF. SUMMARY Recent advances have provided insights into the pathophysiology of HFpEF in hypertension. Such knowledge provides novel opportunities for therapeutic strategies in the treatment of hypertensive HFpEF.
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23
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Toedebusch R, Belenchia A, Pulakat L. Diabetic Cardiomyopathy: Impact of Biological Sex on Disease Development and Molecular Signatures. Front Physiol 2018; 9:453. [PMID: 29773993 PMCID: PMC5943496 DOI: 10.3389/fphys.2018.00453] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/11/2018] [Indexed: 12/14/2022] Open
Abstract
Diabetic cardiomyopathy refers to a unique set of heart-specific pathological variables induced by hyperglycemia and insulin resistance. Given that cardiovascular disease (CVD) is the leading cause of death in the world, and type 2 diabetes incidence continues to rise, understanding the complex interplay between these two morbidities and developing novel therapeutic strategies is vital. Two hallmark characteristics specific to diabetic cardiomyopathy are diastolic dysfunction and cardiac structural mal-adaptations, arising from cardiac cellular responses to the complex toxicity induced by hyperglycemia with or without hyperinsulinemia. While type 2 diabetes is more prevalent in men compared to women, cardiovascular risk is higher in diabetic women than in diabetic men, suggesting that diabetic women take a steeper path to cardiomyopathy and heart failure. Accumulating evidence from randomized clinical trials indicate that although pre-menopausal women have lower risk of CVDs, compared to age-matched men, this advantage is lost in diabetic pre-menopausal women, which suggests estrogen availability does not protect from increased cardiovascular risk. Notably, few human studies have assessed molecular and cellular mechanisms regarding similarities and differences in the progression of diabetic cardiomyopathy in men versus women. Additionally, most pre-clinical rodent studies fail to include female animals, leaving a void in available data to truly understand the impact of biological sex differences in diabetes-induced dysfunction of cardiovascular cells. Elegant reviews in the past have discussed in detail the roles of estrogen-mediated signaling in cardiovascular protection, sex differences associated with telomerase activity in the heart, and cardiac responses to exercise. In this review, we focus on the emerging cellular and molecular markers that define sex differences in diabetic cardiomyopathy based on the recent clinical and pre-clinical evidence. We also discuss miR-208a, MED13, and AT2R, which may provide new therapeutic targets with hopes to develop novel treatment paradigms to treat diabetic cardiomyopathy uniquely between men and women.
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Affiliation(s)
- Ryan Toedebusch
- Cardiovascular Medicine Division, Department of Medicine, University of Missouri, Columbia, MO, United States.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
| | - Anthony Belenchia
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - Lakshmi Pulakat
- Cardiovascular Medicine Division, Department of Medicine, University of Missouri, Columbia, MO, United States.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
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24
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Wang Z, Patel JR, Schreier DA, Hacker TA, Moss RL, Chesler NC. Organ-level right ventricular dysfunction with preserved Frank-Starling mechanism in a mouse model of pulmonary arterial hypertension. J Appl Physiol (1985) 2018; 124:1244-1253. [PMID: 29369739 PMCID: PMC6008075 DOI: 10.1152/japplphysiol.00725.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/08/2018] [Accepted: 01/22/2018] [Indexed: 01/08/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rapidly fatal disease in which mortality is due to right ventricular (RV) failure. It is unclear whether RV dysfunction initiates at the organ level or the subcellular level or both. We hypothesized that chronic pressure overload-induced RV dysfunction begins at the organ level with preserved Frank-Starling mechanism in myocytes. To test this hypothesis, we induced PAH with Sugen + hypoxia (HySu) in mice and measured RV whole organ and subcellular functional changes by in vivo pressure-volume measurements and in vitro trabeculae length-tension measurements, respectively, at multiple time points for up to 56 days. We observed progressive changes in RV function at the organ level: in contrast to early PAH (14-day HySu), in late PAH (56-day HySu) ejection fraction and ventricular-vascular coupling were decreased. At the subcellular level, direct measurements of myofilament contraction showed that RV contractile force was similarly increased at any stage of PAH development. Moreover, cross-bridge kinetics were not changed and length dependence of force development (Frank-Starling relation) were not different from baseline in any PAH group. Histological examinations confirmed increased cardiomyocyte cross-sectional area and decreased von Willebrand factor expression in RVs with PAH. In summary, RV dysfunction developed at the organ level with preserved Frank-Starling mechanism in myofilaments, and these results provide novel insight into the development of RV dysfunction, which is critical to understanding the mechanisms of RV failure. NEW & NOTEWORTHY A multiscale investigation of pulmonary artery pressure overload in mice showed time-dependent organ-level right ventricular (RV) dysfunction with preserved Frank-Starling relations in myofilaments. Our findings provide novel insight into the development of RV dysfunction, which is critical to understanding mechanisms of RV failure.
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Affiliation(s)
- Zhijie Wang
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin
- Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado
| | - Jitandrakumar R Patel
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison , Madison, Wisconsin
| | - David A Schreier
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin
| | - Timothy A Hacker
- Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
| | - Richard L Moss
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison , Madison, Wisconsin
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin
- Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
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25
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Nguyen-Truong M, Wang Z. Biomechanical Properties and Mechanobiology of Cardiac ECM. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1098:1-19. [PMID: 30238363 DOI: 10.1007/978-3-319-97421-7_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The heart is comprised of cardiac cells and extracellular matrix (ECM) which function together to pump blood throughout the body, provide organs with nutrients and oxygen, and remove metabolic wastes. Cardiac ECM provides a scaffold to cardiac cells and contributes to the mechanical properties and function of the cardiac tissue. Recently, more evidence suggests that cardiac ECM plays an active role in cardiac remodeling in response to mechanical loads. To that end, we provide an overview of the structure and function of the heart and the currently available in vivo and ex vivo mechanical measurements of cardiac tissues. We also review the biomechanical properties of cardiac tissues including the myocardium and heart valves, with a discussion on the differences between the right ventricle and left ventricle. Lastly, we go into the mechanical factors involved in cardiac remodeling and review the mechanobiology of cardiac tissues, i.e., the biomechanical responses at the cellular and tissue level, with an emphasis on the impact on the cardiac ECM. The regulation of cardiac ECM on cell function, which is a new and open area of research, is also briefly discussed. Future investigation into the ECM deposition and the interaction of cardiac cells and ECM components for mechanotransduction can assist to understand cardiac remodeling and inspire new therapies for cardiac diseases.
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Affiliation(s)
| | - Zhijie Wang
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA. .,Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA.
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26
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Peyronnet R, Bollensdorff C, Capel RA, Rog-Zielinska EA, Woods CE, Charo DN, Lookin O, Fajardo G, Ho M, Quertermous T, Ashley EA, Kohl P. Load-dependent effects of apelin on murine cardiomyocytes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:333-343. [PMID: 28935153 PMCID: PMC5726609 DOI: 10.1016/j.pbiomolbio.2017.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/26/2023]
Abstract
The apelin peptide is described as one of the most potent inotropic agents, produced endogenously in a wide range of cells, including cardiomyocytes. Despite positive effects on cardiac contractility in multicellular preparations, as well as indications of cardio-protective actions in several diseases, its effects and mechanisms of action at the cellular level are incompletely understood. Here, we report apelin effects on dynamic mechanical characteristics of single ventricular cardiomyocytes, isolated from mouse models (control, apelin-deficient [Apelin-KO], apelin-receptor KO mouse [APJ-KO]), and rat. Dynamic changes in maximal velocity of cell shortening and relaxation were monitored. In addition, more traditional indicators of inotropic effects, such as maximum shortening (in mechanically unloaded cells) or peak force development (in auxotonic contracting cells, preloaded using the carbon fibre technique) were studied. The key finding is that, using Apelin-KO cardiomyocytes exposed to different preloads with the 2-carbon fibre technique, we observe a lowering of the slope of the end-diastolic stress-length relation in response to 10 nM apelin, an effect that is preload-dependent. This suggests a positive lusitropic effect of apelin, which could explain earlier counter-intuitive findings on an apelin-induced increase in contractility occurring without matching rise in oxygen consumption.
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Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg · Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, NHLI, Heart Science Centre, UK.
| | - Christian Bollensdorff
- Imperial College London, NHLI, Heart Science Centre, UK; Sidra Medical and Research Center, Qatar Foundation, Qatar
| | | | - Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg · Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, NHLI, Heart Science Centre, UK
| | - Christopher E Woods
- Stanford University Division of Cardiovascular Medicine, Stanford, USA; Palo Alto Medical Foundation, Burlingame, CA, USA
| | - David N Charo
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | - Oleg Lookin
- Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russian Federation
| | - Giovanni Fajardo
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | - Michael Ho
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | | | - Euan A Ashley
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg · Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, NHLI, Heart Science Centre, UK
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27
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Tam MC, Lee R, Cascino TM, Konerman MC, Hummel SL. Current Perspectives on Systemic Hypertension in Heart Failure with Preserved Ejection Fraction. Curr Hypertens Rep 2017; 19:12. [PMID: 28233237 DOI: 10.1007/s11906-017-0709-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) is a prevalent but incompletely understood syndrome. Traditional models of HFpEF pathophysiology revolve around systemic HTN and other causes of increased left ventricular afterload leading to left ventricular hypertrophy (LVH) and diastolic dysfunction. However, emerging models attribute the development of HFpEF to systemic proinflammatory changes secondary to common comorbidities which include HTN. Alterations in passive ventricular stiffness, ventricular-arterial coupling, peripheral microvascular function, systolic reserve, and chronotropic response occur. As a result, HFpEF is heterogeneous in nature, making it difficult to prescribe uniform therapies to all patients. Nonetheless, treating systemic HTN remains a cornerstone of HFpEF management. Antihypertensive therapies have been linked to LVH regression and improvement in diastolic dysfunction. However, to date, no therapies have definitive mortality benefit in HFpEF. Non-pharmacologic management for HTN, including dietary modification, exercise, and treating sleep disordered breathing, may provide some morbidity benefit in the HFpEF population. Future research is need to identify effective treatments, perhaps in more specific subgroups, and focus may need to shift from reducing mortality to improving exercise capacity and symptoms. Tailoring antihypertensive therapies to specific phenotypes of HFpEF may be an important component of this strategy.
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Affiliation(s)
- Marty C Tam
- Frankel Cardiovascular Center, University of Michigan Health System, Ann Arbor, MI, USA
| | - Ran Lee
- Frankel Cardiovascular Center, University of Michigan Health System, Ann Arbor, MI, USA
| | - Thomas M Cascino
- Frankel Cardiovascular Center, University of Michigan Health System, Ann Arbor, MI, USA
| | - Matthew C Konerman
- Frankel Cardiovascular Center, University of Michigan Health System, Ann Arbor, MI, USA
| | - Scott L Hummel
- Frankel Cardiovascular Center, University of Michigan Health System, Ann Arbor, MI, USA. .,Ann Arbor Veterans Affairs Health System, 1500 E. Medical Center Drive, 2383 CVC/SPC 5853, Ann Arbor, MI, 48109, USA.
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28
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Rain S, Andersen S, Najafi A, Gammelgaard Schultz J, da Silva Gonçalves Bós D, Handoko ML, Bogaard HJ, Vonk-Noordegraaf A, Andersen A, van der Velden J, Ottenheijm CAC, de Man FS. Right Ventricular Myocardial Stiffness in Experimental Pulmonary Arterial Hypertension: Relative Contribution of Fibrosis and Myofibril Stiffness. Circ Heart Fail 2017; 9:CIRCHEARTFAILURE.115.002636. [PMID: 27370069 PMCID: PMC4956674 DOI: 10.1161/circheartfailure.115.002636] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/12/2016] [Indexed: 11/17/2022]
Abstract
Supplemental Digital Content is available in the text. Background— The purpose of this study was to determine the relative contribution of fibrosis-mediated and myofibril-mediated stiffness in rats with mild and severe right ventricular (RV) dysfunction. Methods and Results— By performing pulmonary artery banding of different diameters for 7 weeks, mild RV dysfunction (Ø=0.6 mm) and severe RV dysfunction (Ø=0.5 mm) were induced in rats. The relative contribution of fibrosis- and myofibril-mediated RV stiffness was determined in RV trabecular strips. Total myocardial stiffness was increased in trabeculae from both mild and severe RV dysfunction in comparison to controls. In severe RV dysfunction, increased RV myocardial stiffness was explained by both increased fibrosis-mediated stiffness and increased myofibril-mediated stiffness, whereas in mild RV dysfunction, only myofibril-mediated stiffness was increased in comparison to control. Histological analyses revealed that RV fibrosis gradually increased with severity of RV dysfunction, whereas the ratio of collagen I/III expression was only elevated in severe RV dysfunction. Stiffness measurements in single membrane-permeabilized RV cardiomyocytes demonstrated a gradual increase in RV myofibril stiffness, which was partially restored by protein kinase A in both mild and severe RV dysfunction. Increased expression of compliant titin isoforms was observed only in mild RV dysfunction, whereas titin phosphorylation was reduced in both mild and severe RV dysfunction. Conclusions— RV myocardial stiffness is increased in rats with mild and severe RV dysfunction. In mild RV dysfunction, stiffness is mainly determined by increased myofibril stiffness. In severe RV dysfunction, both myofibril- and fibrosis-mediated stiffness contribute to increased RV myocardial stiffness.
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Affiliation(s)
- Silvia Rain
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Stine Andersen
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Aref Najafi
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Jacob Gammelgaard Schultz
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Denielli da Silva Gonçalves Bós
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - M Louis Handoko
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Harm-Jan Bogaard
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Anton Vonk-Noordegraaf
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Asger Andersen
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Jolanda van der Velden
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Coen A C Ottenheijm
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Frances S de Man
- From the Department of Pulmonology (S.R., D.d.S.G.B., H.-J.B., A.V.-N., F.S.d.M.), Department of Physiology (S.R., A.N., D.d.S.G.B., M.L.H., J.v.d.V., C.A.C.O., F.S.d.M.), and Department of Cardiology (M.L.H.), Vrije Universiteit University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands (M.L.H.); Department of Cardiology, Aarhus University Hospital, Denmark (S. Anderson, A.N., J.G.S., A. Anderson); and Interuniversity Cardiology Institute of the Netherlands, The Netherlands Heart Institute, Utrecht (J.v.d.V.).
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29
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Valero-Munoz M, Li S, Wilson RM, Boldbaatar B, Iglarz M, Sam F. Dual Endothelin-A/Endothelin-B Receptor Blockade and Cardiac Remodeling in Heart Failure With Preserved Ejection Fraction. Circ Heart Fail 2017; 9:CIRCHEARTFAILURE.116.003381. [PMID: 27810862 DOI: 10.1161/circheartfailure.116.003381] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/03/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND Despite the increasing prevalence of heart failure with preserved ejection fraction (HFpEF) in humans, there remains no evidence-based therapies for HFpEF. Endothelin-1 (ET-1) antagonists are a possibility because elevated ET-1 levels are associated with adverse cardiovascular effects, such as arterial and pulmonary vasoconstriction, impaired left ventricular (LV) relaxation, and stimulation of LV hypertrophy. LV hypertrophy is a common phenotype in HFpEF, particularly when associated with hypertension. METHODS AND RESULTS In the present study, we found that ET-1 levels were significantly elevated in patients with chronic stable HFpEF. We then sought to investigate the effects of chronic macitentan, a dual ET-A/ET-B receptor antagonist, on cardiac structure and function in a murine model of HFpEF induced by chronic aldosterone infusion. Macitentan caused LV hypertrophy regression independent of blood pressure changes in HFpEF. Although macitentan did not modulate diastolic dysfunction in HFpEF, it significantly reduced wall thickness and relative wall thickness after 2 weeks of therapy. In vitro studies showed that macitentan decreased the aldosterone-induced cardiomyocyte hypertrophy. These changes were mediated by a reduction in the expression of cardiac myocyte enhancer factor 2a. Moreover, macitentan improved adverse cardiac remodeling, by reducing the stiffer cardiac collagen I and titin n2b expression in the left ventricle of mice with HFpEF. CONCLUSIONS These findings indicate that dual ET-A/ET-B receptor inhibition improves HFpEF by abrogating adverse cardiac remodeling via antihypertrophic mechanisms and by reducing stiffness. Additional studies are needed to explore the role of dual ET-1 receptor antagonists in patients with HFpEF.
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Affiliation(s)
- Maria Valero-Munoz
- From the Whitaker Cardiovascular Institute (M.V.-M., S.L., R.M.W., B.B., F.S.) and Cardiovascular Section and Evans Department of Medicine (F.S.), Boston University School of Medicine, MA; and Actelion Pharmaceuticals Ltd., Allschwil, Switzerland (M.I.)
| | - Shanpeng Li
- From the Whitaker Cardiovascular Institute (M.V.-M., S.L., R.M.W., B.B., F.S.) and Cardiovascular Section and Evans Department of Medicine (F.S.), Boston University School of Medicine, MA; and Actelion Pharmaceuticals Ltd., Allschwil, Switzerland (M.I.)
| | - Richard M Wilson
- From the Whitaker Cardiovascular Institute (M.V.-M., S.L., R.M.W., B.B., F.S.) and Cardiovascular Section and Evans Department of Medicine (F.S.), Boston University School of Medicine, MA; and Actelion Pharmaceuticals Ltd., Allschwil, Switzerland (M.I.)
| | - Batbold Boldbaatar
- From the Whitaker Cardiovascular Institute (M.V.-M., S.L., R.M.W., B.B., F.S.) and Cardiovascular Section and Evans Department of Medicine (F.S.), Boston University School of Medicine, MA; and Actelion Pharmaceuticals Ltd., Allschwil, Switzerland (M.I.)
| | - Marc Iglarz
- From the Whitaker Cardiovascular Institute (M.V.-M., S.L., R.M.W., B.B., F.S.) and Cardiovascular Section and Evans Department of Medicine (F.S.), Boston University School of Medicine, MA; and Actelion Pharmaceuticals Ltd., Allschwil, Switzerland (M.I.)
| | - Flora Sam
- From the Whitaker Cardiovascular Institute (M.V.-M., S.L., R.M.W., B.B., F.S.) and Cardiovascular Section and Evans Department of Medicine (F.S.), Boston University School of Medicine, MA; and Actelion Pharmaceuticals Ltd., Allschwil, Switzerland (M.I.).
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Vikhlyantsev IM, Podlubnaya ZA. Nuances of electrophoresis study of titin/connectin. Biophys Rev 2017; 9:189-199. [PMID: 28555301 PMCID: PMC5498330 DOI: 10.1007/s12551-017-0266-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 04/28/2017] [Indexed: 01/03/2023] Open
Abstract
Almost 40 years has passed since the discovery of giant elastic protein titin (also known as connectin) of striated and smooth muscles using gel electrophoresis. Sodium dodecyl sulfate polyacrylamide gel electrophoresis is a major technique for studying the isoform composition and content of titin. This review provides historical insights into the technical aspects of the electrophoresis methods used to identify titin and its isoforms. We particularly focus on the nuances of the technique that improve the preservation of its primary structure so that its high molecular weight isoforms can be visualized.
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Affiliation(s)
- Ivan M Vikhlyantsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Street 3, Pushchino, 142290, Russia.
- Pushchino State Institute of Natural Science, Nauki Street 3, Pushchino, 142290, Russia.
| | - Zoya A Podlubnaya
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Street 3, Pushchino, 142290, Russia
- Pushchino State Institute of Natural Science, Nauki Street 3, Pushchino, 142290, Russia
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Slater RE, Strom JG, Granzier H. Effect of exercise on passive myocardial stiffness in mice with diastolic dysfunction. J Mol Cell Cardiol 2017; 108:24-33. [PMID: 28476659 DOI: 10.1016/j.yjmcc.2017.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 04/24/2017] [Accepted: 04/27/2017] [Indexed: 12/20/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome, characterized by increased diastolic stiffness and a preserved ejection fraction, with no effective treatment options. Here we studied the therapeutic potential of exercise for improving diastolic function in a mouse model with HFpEF-like symptoms, the TtnΔIAjxn mouse model. TtnΔIAjxn mice have increased diastolic stiffness and reduced exercise tolerance, mimicking aspects of HFpEF observed in patients. We investigated the effect of free-wheel running exercise on diastolic function. Mechanical studies on cardiac muscle strips from the LV free wall revealed that both TtnΔIAjxn and wildtype (WT) exercised mice had a reduction in passive stiffness, relative to sedentary controls. In both genotypes, this reduction is due to an increase in the compliance of titin whereas ECM-based stiffness was unaffected. Phosphorylation of titin's PEVK and N2B spring elements were assayed with phospho-site specific antibodies. Exercised mice had decreased PEVK phosphorylation and increased N2B phosphorylation both of which are predicted to contribute to the increased compliance of titin. Since exercise lowers the heart rate we examined whether reduction in heart rate per se can improve passive stiffness by administering the heart-rate-lowering drug ivabradine. Ivabradine lowered heart rate in our study but it did not affect passive tension, in neither WT nor TtnΔIAjxn mice. We conclude that exercise is beneficial for decreasing passive stiffness and that it involves beneficial alterations in titin phosphorylation.
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Affiliation(s)
- Rebecca E Slater
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States
| | - Joshua G Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States; Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States.
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Briana DD, Germanou K, Boutsikou M, Boutsikou T, Athanasopoulos N, Marmarinos A, Gourgiotis D, Malamitsi-Puchner A. Potential prognostic biomarkers of cardiovascular disease in fetal macrosomia: the impact of gestational diabetes. J Matern Fetal Neonatal Med 2017; 31:895-900. [PMID: 28298172 DOI: 10.1080/14767058.2017.1300651] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Fetal macrosomia is associated with cardiac hypertrophy and increased cardiovascular risk. Cardiac biomarkers may play diagnostic/prognostic role in cardiovascular disease. We tested whether cardiac biomarkers are differentially expressed in cord blood samples of full-term singleton large-for-gestational-age (LGA), as compared to appropriate-for-gestational-age (AGA) pregnancies. METHODS Cardiotrophin-1 (CT-1), Titin, pentraxin (PTX-3) and soluble CD36 (sCD36) concentrations were determined in 80 cord blood samples from a) LGA pregnancies due to maternal diabetes (n = 8), overweight/obese (n = 11), excessive weight gain (n = 7), without specific pathology (n = 14), b) AGA normal pregnancies (controls, n = 40). Neonates were classified as LGA or AGA based on customized birth weight (BW) standards. RESULTS CT-1 and Titin concentrations were higher in LGA than AGA pregnancies (p < .001 and p = .023, respectively). A subgroup analysis (in the LGA group) showed increased CT-1 concentrations only in diabetic pregnancies. PTX-3 and sCD36 concentrations were similar in LGA and AGA fetuses. In the LGA group, PTX-3 concentrations positively correlated with birth-weight (r = .416, p = .008) and respective sCD36 concentrations (r = .443, p = .004). CONCLUSION Higher Titin concentrations in LGAs possibly represent a candidate molecular mechanism underlying the association between fetal macrosomia and cardiomyocyte/diastolic dysfunction. CT-1 is up-regulated only in LGAs exposed to maternal diabetes. PTX-3 and sCD36 are probably not affected by excessive fetal growth.
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Affiliation(s)
- Despina D Briana
- a Department of Neonatology , National and Kapodistrian University of Athens , Athens , Greece
| | - Kleopatra Germanou
- a Department of Neonatology , National and Kapodistrian University of Athens , Athens , Greece
| | - Maria Boutsikou
- a Department of Neonatology , National and Kapodistrian University of Athens , Athens , Greece
| | - Theodora Boutsikou
- a Department of Neonatology , National and Kapodistrian University of Athens , Athens , Greece
| | - Nikolaos Athanasopoulos
- a Department of Neonatology , National and Kapodistrian University of Athens , Athens , Greece
| | - Antonios Marmarinos
- b Laboratory of Clinical Biochemistry-Molecular Diagnostics, 2nd Department of Pediatrics , National and Kapodistrian University of Athens , Athens , Greece
| | - Dimitrios Gourgiotis
- b Laboratory of Clinical Biochemistry-Molecular Diagnostics, 2nd Department of Pediatrics , National and Kapodistrian University of Athens , Athens , Greece
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Shalabi N, Cornachione A, de Souza Leite F, Vengallatore S, Rassier DE. Residual force enhancement is regulated by titin in skeletal and cardiac myofibrils. J Physiol 2017; 595:2085-2098. [PMID: 28028799 DOI: 10.1113/jp272983] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/12/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS When a skeletal muscle is stretched while it contracts, the muscle produces a relatively higher force than the force from an isometric contraction at the same length: a phenomenon referred to as residual force enhancement. Residual force enhancement is puzzling because it cannot be directly explained by the classical force-length relationship and the sliding filament theory of contraction, the main paradigms in the muscle field. We used custom-built instruments to measure residual force enhancement in skeletal myofibrils, and, for the first time, in cardiac myofibrils. Our data report that residual force enhancement is present in skeletal muscles, but not cardiac muscles, and is regulated by the different isoforms of the titin protein filaments. ABSTRACT When a skeletal muscle contracts isometrically, the muscle produces a force that is relative to the final isometric sarcomere length (SL). However, when the same final SL is reached by stretching the muscle while it contracts, the muscle produces a relatively higher force: a phenomenon commonly referred to as residual force enhancement. In this study, we investigated residual force enhancement in rabbit skeletal psoas myofibrils and, for the first time, cardiac papillary myofibrils. A custom-built atomic force microscope was used in experiments that stretched myofibrils before and after inhibiting myosin and actin interactions to determine whether the different cardiac and skeletal titin isoforms regulate residual force enhancement. At SLs ranging from 2.24 to 3.13 μm, the skeletal myofibrils enhanced the force by an average of 9.0%, and by 29.5% after hindering myosin and actin interactions. At SLs ranging from 1.80 to 2.29 μm, the cardiac myofibrils did not enhance the force before or after hindering myosin and actin interactions. We conclude that residual force enhancement is present only in skeletal muscles and is dependent on the titin isoforms.
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Affiliation(s)
- Nabil Shalabi
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada, H3A 2K6
| | - Anabelle Cornachione
- Department of Kinesiology and Physical Education, McGill University, 475 Pine Avenue West, Montreal, Quebec, Canada, H2W 1S4
| | - Felipe de Souza Leite
- Department of Kinesiology and Physical Education, McGill University, 475 Pine Avenue West, Montreal, Quebec, Canada, H2W 1S4
| | - Srikar Vengallatore
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada, H3A 2K6
| | - Dilson E Rassier
- Department of Kinesiology and Physical Education, McGill University, 475 Pine Avenue West, Montreal, Quebec, Canada, H2W 1S4
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Crossley DA, Burggren WW, Reiber CL, Altimiras J, Rodnick KJ. Mass Transport: Circulatory System with Emphasis on Nonendothermic Species. Compr Physiol 2016; 7:17-66. [PMID: 28134997 DOI: 10.1002/cphy.c150010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mass transport can be generally defined as movement of material matter. The circulatory system then is a biological example given its role in the movement in transporting gases, nutrients, wastes, and chemical signals. Comparative physiology has a long history of providing new insights and advancing our understanding of circulatory mass transport across a wide array of circulatory systems. Here we focus on circulatory function of nonmodel species. Invertebrates possess diverse convection systems; that at the most complex generate pressures and perform at a level comparable to vertebrates. Many invertebrates actively modulate cardiovascular function using neuronal, neurohormonal, and skeletal muscle activity. In vertebrates, our understanding of cardiac morphology, cardiomyocyte function, and contractile protein regulation by Ca2+ highlights a high degree of conservation, but differences between species exist and are coupled to variable environments and body temperatures. Key regulators of vertebrate cardiac function and systemic blood pressure include the autonomic nervous system, hormones, and ventricular filling. Further chemical factors regulating cardiovascular function include adenosine, natriuretic peptides, arginine vasotocin, endothelin 1, bradykinin, histamine, nitric oxide, and hydrogen sulfide, to name but a few. Diverse vascular morphologies and the regulation of blood flow in the coronary and cerebral circulations are also apparent in nonmammalian species. Dynamic adjustments of cardiovascular function are associated with exercise on land, flying at high altitude, prolonged dives by marine mammals, and unique morphology, such as the giraffe. Future studies should address limits of gas exchange and convective transport, the evolution of high arterial pressure across diverse taxa, and the importance of the cardiovascular system adaptations to extreme environments. © 2017 American Physiological Society. Compr Physiol 7:17-66, 2017.
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Affiliation(s)
- Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Warren W Burggren
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Carl L Reiber
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Jordi Altimiras
- AVIAN Behavioral Genomics and Physiology, IFM Biology, Linköping University, Linköping, Sweden
| | - Kenneth J Rodnick
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho, USA
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Keen AN, Klaiman JM, Shiels HA, Gillis TE. Temperature-induced cardiac remodelling in fish. ACTA ACUST UNITED AC 2016; 220:147-160. [PMID: 27852752 PMCID: PMC5278617 DOI: 10.1242/jeb.128496] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Thermal acclimation causes the heart of some fish species to undergo significant remodelling. This includes changes in electrical activity, energy utilization and structural properties at the gross and molecular level of organization. The purpose of this Review is to summarize the current state of knowledge of temperature-induced structural remodelling in the fish ventricle across different levels of biological organization, and to examine how such changes result in the modification of the functional properties of the heart. The structural remodelling response is thought to be responsible for changes in cardiac stiffness, the Ca2+ sensitivity of force generation and the rate of force generation by the heart. Such changes to both active and passive properties help to compensate for the loss of cardiac function caused by a decrease in physiological temperature. Hence, temperature-induced cardiac remodelling is common in fish that remain active following seasonal decreases in temperature. This Review is organized around the ventricular phases of the cardiac cycle – specifically diastolic filling, isovolumic pressure generation and ejection – so that the consequences of remodelling can be fully described. We also compare the thermal acclimation-associated modifications of the fish ventricle with those seen in the mammalian ventricle in response to cardiac pathologies and exercise. Finally, we consider how the plasticity of the fish heart may be relevant to survival in a climate change context, where seasonal temperature changes could become more extreme and variable. Summary: Thermal acclimation of some temperate fishes causes extensive remodelling of the heart. The resultant changes to the active and passive properties of the heart represent a highly integrated phenotypic response.
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Affiliation(s)
- Adam N Keen
- Division of Cardiovascular Science, School of Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9NT, UK
| | - Jordan M Klaiman
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98109, USA
| | - Holly A Shiels
- Division of Cardiovascular Science, School of Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9NT, UK
| | - Todd E Gillis
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Methawasin M, Strom JG, Slater RE, Fernandez V, Saripalli C, Granzier H. Experimentally Increasing the Compliance of Titin Through RNA Binding Motif-20 (RBM20) Inhibition Improves Diastolic Function In a Mouse Model of Heart Failure With Preserved Ejection Fraction. Circulation 2016; 134:1085-1099. [PMID: 27630136 DOI: 10.1161/circulationaha.116.023003] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/05/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Left ventricular (LV) stiffening contributes to heart failure with preserved ejection fraction (HFpEF), a syndrome with no effective treatment options. Increasing the compliance of titin in the heart has become possible recently through inhibition of the splicing factor RNA binding motif-20. Here, we investigated the effects of increasing the compliance of titin in mice with diastolic dysfunction. METHODS Mice in which the RNA recognition motif (RRM) of one of the RNA binding motif-20 alleles was floxed and that expressed the MerCreMer transgene under control of the αMHC promoter (referred to as cRbm20ΔRRM mice) were used. Mice underwent transverse aortic constriction (TAC) surgery and deoxycorticosterone acetate (DOCA) pellet implantation. RRM deletion in adult mice was triggered by injecting raloxifene (cRbm20ΔRRM-raloxifene), with dimethyl sulfoxide (DMSO)-injected mice (cRbm20ΔRRM-DMSO) as the control. Diastolic function was investigated with echocardiography and pressure-volume analysis; passive stiffness was studied in LV muscle strips and isolated cardiac myocytes before and after elimination of titin-based stiffness. Treadmill exercise performance was also studied. Titin isoform expression was evaluated with agarose gels. RESULTS cRbm20ΔRRM-raloxifene mice expressed large titins in the hearts, called supercompliant titin (N2BAsc), which, within 3 weeks after raloxifene injection, made up ≈45% of total titin. TAC/DOCA cRbm20ΔRRM-DMSO mice developed LV hypertrophy and a marked increase in LV chamber stiffness as shown by both pressure-volume analysis and echocardiography. LV chamber stiffness was normalized in TAC/DOCA cRbm20ΔRRM-raloxifene mice that expressed N2BAsc. Passive stiffness measurements on muscle strips isolated from the LV free wall revealed that extracellular matrix stiffness was equally increased in both groups of TAC/DOCA mice (cRbm20ΔRRM-DMSO and cRbm20ΔRRM-raloxifene). However, titin-based muscle stiffness was reduced in the mice that expressed N2BAsc (TAC/DOCAcRbm20ΔRRM-raloxifene). Exercise testing demonstrated significant improvement in exercise tolerance in TAC/DOCA mice that expressed N2BAsc. CONCLUSIONS Inhibition of the RNA binding motif-20-based titin splicing system upregulates compliant titins, which improves diastolic function and exercise tolerance in the TAC/DOCA model. Titin holds promise as a therapeutic target for heart failure with preserved ejection fraction.
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Affiliation(s)
- Mei Methawasin
- From Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson
| | - Joshua G Strom
- From Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson
| | - Rebecca E Slater
- From Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson
| | - Vanessa Fernandez
- From Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson
| | - Chandra Saripalli
- From Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson
| | - Henk Granzier
- From Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson.
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Aboelkassem Y, Bonilla JA, McCabe KJ, Campbell SG. Contributions of Ca2+-Independent Thin Filament Activation to Cardiac Muscle Function. Biophys J 2016; 109:2101-12. [PMID: 26588569 DOI: 10.1016/j.bpj.2015.09.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/03/2015] [Accepted: 09/11/2015] [Indexed: 12/29/2022] Open
Abstract
Although Ca2+ is the principal regulator of contraction in striated muscle, in vitro evidence suggests that some actin-myosin interaction is still possible even in its absence. Whether this Ca2+-independent activation (CIA) occurs under physiological conditions remains unclear, as does its potential impact on the function of intact cardiac muscle. The purpose of this study was to investigate CIA using computational analysis. We added a structurally motivated representation of this phenomenon to an existing myofilament model, which allowed predictions of CIA-dependent muscle behavior. We found that a certain amount of CIA was essential for the model to reproduce reported effects of nonfunctional troponin C on myofilament force generation. Consequently, those data enabled estimation of ΔGCIA, the energy barrier for activating a thin filament regulatory unit in the absence of Ca2+. Using this estimate of ΔGCIA as a point of reference (∼7 kJ mol(-1)), we examined its impact on various aspects of muscle function through additional simulations. CIA decreased the Hill coefficient of steady-state force while increasing myofilament Ca2+ sensitivity. At the same time, CIA had minimal effect on the rate of force redevelopment after slack/restretch. Simulations of twitch tension show that the presence of CIA increases peak tension while profoundly delaying relaxation. We tested the model's ability to represent perturbations to the Ca2+ regulatory mechanism by analyzing twitch records measured in transgenic mice expressing a cardiac troponin I mutation (R145G). The effects of the mutation on twitch dynamics were fully reproduced by a single parameter change, namely lowering ΔGCIA by 2.3 kJ mol(-1) relative to its wild-type value. Our analyses suggest that CIA is present in cardiac muscle under normal conditions and that its modulation by gene mutations or other factors can alter both systolic and diastolic function.
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Affiliation(s)
- Yasser Aboelkassem
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Jordan A Bonilla
- Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena, California
| | - Kimberly J McCabe
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut.
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Pulcastro HC, Awinda PO, Methawasin M, Granzier H, Dong W, Tanner BCW. Increased Titin Compliance Reduced Length-Dependent Contraction and Slowed Cross-Bridge Kinetics in Skinned Myocardial Strips from Rbm (20ΔRRM) Mice. Front Physiol 2016; 7:322. [PMID: 27524973 PMCID: PMC4966298 DOI: 10.3389/fphys.2016.00322] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/14/2016] [Indexed: 01/12/2023] Open
Abstract
Titin is a giant protein spanning from the Z-disk to the M-band of the cardiac sarcomere. In the I-band titin acts as a molecular spring, contributing to passive mechanical characteristics of the myocardium throughout a heartbeat. RNA Binding Motif Protein 20 (RBM20) is required for normal titin splicing, and its absence or altered function leads to greater expression of a very large, more compliant N2BA titin isoform in Rbm20 homozygous mice (Rbm20ΔRRM) compared to wild-type mice (WT) that almost exclusively express the stiffer N2B titin isoform. Prior studies using Rbm20ΔRRM animals have shown that increased titin compliance compromises muscle ultrastructure and attenuates the Frank-Starling relationship. Although previous computational simulations of muscle contraction suggested that increasing compliance of the sarcomere slows the rate of tension development and prolongs cross-bridge attachment, none of the reported effects of Rbm20ΔRRM on myocardial function have been attributed to changes in cross-bridge cycling kinetics. To test the relationship between increased sarcomere compliance and cross-bridge kinetics, we used stochastic length-perturbation analysis in Ca2+-activated, skinned papillary muscle strips from Rbm20ΔRRM and WT mice. We found increasing titin compliance depressed maximal tension, decreased Ca2+-sensitivity of the tension-pCa relationship, and slowed myosin detachment rate in myocardium from Rbm20ΔRRM vs. WT mice. As sarcomere length increased from 1.9 to 2.2 μm, length-dependent activation of contraction was eliminated in the Rbm20ΔRRM myocardium, even though myosin MgADP release rate decreased ~20% to prolong strong cross-bridge binding at longer sarcomere length. These data suggest that increasing N2BA expression may alter cardiac performance in a length-dependent manner, showing greater deficits in tension production and slower cross-bridge kinetics at longer sarcomere length. This study also supports the idea that passive mechanical characteristics of the myocardium influence ensemble cross-bridge behavior and maintenance of tension generation throughout the sarcomere.
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Affiliation(s)
- Hannah C Pulcastro
- Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Peter O Awinda
- Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona Tucson, AZ, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona Tucson, AZ, USA
| | - Wenji Dong
- Department of Integrative Physiology and Neuroscience, Washington State UniversityPullman, WA, USA; Voiland School of Chemical Engineering and Bioengineering, Washington State UniversityPullman, WA, USA
| | - Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
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Dickinson ES, Johnson AS, Ellers O, Dickinson PS. Forces generated during stretch in the heart of the lobster Homarus americanus are anisotropic and are altered by neuromodulators. ACTA ACUST UNITED AC 2016; 219:1187-202. [PMID: 26896540 DOI: 10.1242/jeb.135657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/05/2016] [Indexed: 01/02/2023]
Abstract
Mechanical and neurophysiological anisotropies mediate three-dimensional responses of the heart of ITALIC! Homarus americanus Although hearts ITALIC! in vivoare loaded multi-axially by pressure, studies of invertebrate cardiac function typically use uniaxial tests. To generate whole-heart length-tension curves, stretch pyramids at constant lengthening and shortening rates were imposed uniaxially and biaxially along longitudinal and transverse axes of the beating whole heart. To determine whether neuropeptides that are known to modulate cardiac activity in ITALIC! H. americanusaffect the active or passive components of these length-tension curves, we also performed these tests in the presence of SGRNFLRFamide (SGRN) and GYSNRNYLRFamide (GYS). In uniaxial and biaxial tests, both passive and active forces increased with stretch along both measurement axes. The increase in passive forces was anisotropic, with greater increases along the longitudinal axis. Passive forces showed hysteresis and active forces were higher during lengthening than shortening phases of the stretch pyramid. Active forces at a given length were increased by both neuropeptides. To exert these effects, neuropeptides might have acted indirectly on the muscle via their effects on the cardiac ganglion, directly on the neuromuscular junction, or directly on the muscles. Because increases in response to stretch were also seen in stimulated motor nerve-muscle preparations, at least some of the effects of the peptides are likely peripheral. Taken together, these findings suggest that flexibility in rhythmic cardiac contractions results from the amplified effects of neuropeptides interacting with the length-tension characteristics of the heart.
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Affiliation(s)
- E S Dickinson
- Biology Department, Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA
| | - A S Johnson
- Biology Department, Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA
| | - O Ellers
- Biology Department, Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA
| | - P S Dickinson
- Biology Department, Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA
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Papalamprou A, Griffiths LG. Cardiac Extracellular Matrix Scaffold Generated Using Sarcomeric Disassembly and Antigen Removal. Ann Biomed Eng 2015. [DOI: 10.1007/s10439-015-1404-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Bowden MA, Tesch GH, Julius TL, Rosli S, Love JE, Ritchie RH. Earlier onset of diabesity-Induced adverse cardiac remodeling in female compared to male mice. Obesity (Silver Spring) 2015; 23:1166-77. [PMID: 25959739 DOI: 10.1002/oby.21072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/09/2015] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Emerging evidence suggests female type 2 diabetes (T2DM) patients may fare worse than males with respect to cardiovascular complications. Hence the impact of sex on relative progression of left ventricular (LV) remodeling in obese db/db mice was characterized. METHODS The changes in parameters of LV hypertrophy (heart weight, pro-hypertrophic gene expression, cardiomyocyte size) and fibrosis (LV collagen deposition and oxidative stress), in parallel with body weight and blood glucose and lipid profiles, in male and female db/db T2DM mice, at 10, 14, and 18 weeks of age, were determined. RESULTS Diabesity-induced cardiac remodeling was at least comparable in female (compared to male) mice. Females exhibited enhanced systemic oxidative stress and nonesterified fatty acid levels. Progression of LV pro-hypertrophic (β-myosin heavy chain, B-type natriuretic peptide) and pro-oxidant gene expression (NADPH oxidase subunit Nox2, plasminogen activator inhibitor-1 PAI-I) was, however, exaggerated in females when expressed relative to 10-week-old db/db mice. Increased cardiomyocyte width was also evident earlier in db/db females than males. No other gender differences were observed. CONCLUSIONS Progressive, age-dependent development of cardiac remodeling in db/db mice parallels impairments in glucose handling and oxidative stress. Certain aspects of the T2DM-induced LV remodeling response may have an earlier and/or exaggerated onset in diabetic females.
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Affiliation(s)
- Marissa A Bowden
- Heart Failure Pharmacology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Greg H Tesch
- Department of Nephrology, Monash Medical Centre, Clayton, Victoria, Australia
- Department of Medicine, Monash University, Clayton, Victoria, Australia
| | - Tracey L Julius
- Heart Failure Pharmacology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Sarah Rosli
- Heart Failure Pharmacology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Jane E Love
- Heart Failure Pharmacology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Rebecca H Ritchie
- Heart Failure Pharmacology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
- Department of Medicine, Monash University, Clayton, Victoria, Australia
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Campbell KS, Sorrell VL. Cell- and molecular-level mechanisms contributing to diastolic dysfunction in HFpEF. J Appl Physiol (1985) 2015; 119:1228-32. [PMID: 25911687 DOI: 10.1152/japplphysiol.01168.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/12/2015] [Indexed: 02/08/2023] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) is the default diagnosis for patients who have symptoms of heart failure, an ejection fraction >0.5, and evidence of diastolic dysfunction. The clinical condition, which was largely unrecognized 30 years ago, is now a major health problem and currently accounts for 50% of all patients with heart failure. Clinical studies show that patients with HFpEF exhibit increased passive stiffness of the ventricles and a slower rate of pressure decline during diastole. This review discusses some of the cell- and molecular-level mechanisms that contribute to these effects and focuses on data obtained using human samples. Collagen cross linking, modulation of protein kinase G-related pathways, Ca(2+) handling, and strain-dependent detachment of cross bridges are highlighted as potential factors that could be modulated to improve ventricular function in patients with HFpEF.
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Affiliation(s)
- Kenneth S Campbell
- Department of Physiology and Center for Muscle Biology, Linda and Jack Gill Heart Institute, University of Kentucky, Lexington, Kentucky; and
| | - Vincent L Sorrell
- Division of Cardiovascular Medicine, Linda and Jack Gill Heart Institute, University of Kentucky, Lexington, Kentucky
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Zile MR, Baicu CF, Ikonomidis JS, Stroud RE, Nietert PJ, Bradshaw AD, Slater R, Palmer BM, Van Buren P, Meyer M, Redfield MM, Bull DA, Granzier HL, LeWinter MM. Myocardial stiffness in patients with heart failure and a preserved ejection fraction: contributions of collagen and titin. Circulation 2015; 131:1247-59. [PMID: 25637629 DOI: 10.1161/circulationaha.114.013215] [Citation(s) in RCA: 460] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/26/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND The purpose of this study was to determine whether patients with heart failure and a preserved ejection fraction (HFpEF) have an increase in passive myocardial stiffness and the extent to which discovered changes depend on changes in extracellular matrix fibrillar collagen and cardiomyocyte titin. METHODS AND RESULTS Seventy patients undergoing coronary artery bypass grafting underwent an echocardiogram, plasma biomarker determination, and intraoperative left ventricular epicardial anterior wall biopsy. Patients were divided into 3 groups: referent control (n=17, no hypertension or diabetes mellitus), hypertension (HTN) without (-) HFpEF (n=31), and HTN with (+) HFpEF (n=22). One or more of the following studies were performed on the biopsies: passive stiffness measurements to determine total, collagen-dependent and titin-dependent stiffness (differential extraction assay), collagen assays (biochemistry or histology), or titin isoform and phosphorylation assays. In comparison with controls, patients with HTN(-)HFpEF had no change in left ventricular end-diastolic pressure, myocardial passive stiffness, collagen, or titin phosphorylation but had an increase in biomarkers of inflammation (C-reactive protein, soluble ST2, tissue inhibitor of metalloproteinase 1). In comparison with both control and HTN(-)HFpEF, patients with HTN(+)HFpEF had increased left ventricular end-diastolic pressure, left atrial volume, N-terminal propeptide of brain natriuretic peptide, total, collagen-dependent, and titin-dependent stiffness, insoluble collagen, increased titin phosphorylation on PEVK S11878(S26), reduced phosphorylation on N2B S4185(S469), and increased biomarkers of inflammation. CONCLUSIONS Hypertension in the absence of HFpEF did not alter passive myocardial stiffness. Patients with HTN(+)HFpEF had a significant increase in passive myocardial stiffness; collagen-dependent and titin-dependent stiffness were increased. These data suggest that the development of HFpEF depends on changes in both collagen and titin homeostasis.
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Affiliation(s)
- Michael R Zile
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.).
| | - Catalin F Baicu
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - John S Ikonomidis
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Robert E Stroud
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Paul J Nietert
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Amy D Bradshaw
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Rebecca Slater
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Bradley M Palmer
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Peter Van Buren
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Markus Meyer
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Margaret M Redfield
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - David A Bull
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Henk L Granzier
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Martin M LeWinter
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
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Herum KM, Lunde IG, Skrbic B, Louch WE, Hasic A, Boye S, Unger A, Brorson SH, Sjaastad I, Tønnessen T, Linke WA, Gomez MF, Christensen G. Syndecan-4 is a key determinant of collagen cross-linking and passive myocardial stiffness in the pressure-overloaded heart. Cardiovasc Res 2015; 106:217-26. [DOI: 10.1093/cvr/cvv002] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 12/20/2014] [Indexed: 01/02/2023] Open
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Cardiac tissue structure, properties, and performance: a materials science perspective. Ann Biomed Eng 2014; 42:2003-13. [PMID: 25081385 DOI: 10.1007/s10439-014-1071-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 07/14/2014] [Indexed: 12/24/2022]
Abstract
From an engineering perspective, many forms of heart disease can be thought of as a reduction in biomaterial performance, in which the biomaterial is the tissue comprising the ventricular wall. In materials science, the structure and properties of a material are recognized to be interconnected with performance. In addition, for most measurements of structure, properties, and performance, some processing is required. Here, we review the current state of knowledge regarding cardiac tissue structure, properties, and performance as well as the processing steps taken to acquire those measurements. Understanding the impact of these factors and their interactions may enhance our understanding of heart function and heart failure. We also review design considerations for cardiac tissue property and performance measurements because, to date, most data on cardiac tissue has been obtained under non-physiological loading conditions. Novel measurement systems that account for these design considerations may improve future experiments and lead to greater insight into cardiac tissue structure, properties, and ultimately performance.
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Pregnancy differentially regulates the collagens types I and III in left ventricle from rat heart. BIOMED RESEARCH INTERNATIONAL 2014; 2014:984785. [PMID: 25147829 PMCID: PMC4131467 DOI: 10.1155/2014/984785] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 01/19/2023]
Abstract
The pathologic cardiac remodeling has been widely documented; however, the physiological cardiac remodeling induced by pregnancy and its reversion in postpartum are poorly understood. In the present study we investigated the changes in collagen I (Col I) and collagen III (Col III) mRNA and protein levels in left ventricle from rat heart during pregnancy and postpartum. Col I and Col III mRNA expression in left ventricle samples during pregnancy and postpartum were analyzed by using quantitative PCR. Data obtained from gene expression show that Col I and Col III in left ventricle are upregulated during pregnancy with reversion in postpartum. In contrast to gene expression, the protein expression evaluated by western blot showed that Col I is downregulated and Col III is upregulated in left ventricle during pregnancy. In conclusion, the pregnancy differentially regulates collagens types I and III in heart; this finding could be an important molecular mechanism that regulates the ventricular stiffness in response to blood volume overload present during pregnancy which is reversed in postpartum.
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Williams SM, Golden-Mason L, Ferguson BS, Schuetze KB, Cavasin MA, Demos-Davies K, Yeager ME, Stenmark KR, McKinsey TA. Class I HDACs regulate angiotensin II-dependent cardiac fibrosis via fibroblasts and circulating fibrocytes. J Mol Cell Cardiol 2014; 67:112-25. [PMID: 24374140 PMCID: PMC4120952 DOI: 10.1016/j.yjmcc.2013.12.013] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 12/12/2013] [Accepted: 12/17/2013] [Indexed: 01/07/2023]
Abstract
Fibrosis, which is defined as excessive accumulation of fibrous connective tissue, contributes to the pathogenesis of numerous diseases involving diverse organ systems. Cardiac fibrosis predisposes individuals to myocardial ischemia, arrhythmias and sudden death, and is commonly associated with diastolic dysfunction. Histone deacetylase (HDAC) inhibitors block cardiac fibrosis in pre-clinical models of heart failure. However, which HDAC isoforms govern cardiac fibrosis, and the mechanisms by which they do so, remains unclear. Here, we show that selective inhibition of class I HDACs potently suppresses angiotensin II (Ang II)-mediated cardiac fibrosis by targeting two key effector cell populations, cardiac fibroblasts and bone marrow-derived fibrocytes. Class I HDAC inhibition blocks cardiac fibroblast cell cycle progression through derepression of the genes encoding the cyclin-dependent kinase (CDK) inhibitors, p15 and p57. In contrast, class I HDAC inhibitors block agonist-dependent differentiation of fibrocytes through a mechanism involving repression of ERK1/2 signaling. These findings define novel roles for class I HDACs in the control of pathological cardiac fibrosis. Furthermore, since fibrocytes have been implicated in the pathogenesis of a variety of human diseases, including heart, lung and kidney failure, our results suggest broad utility for isoform-selective HDAC inhibitors as anti-fibrotic agents that function, in part, by targeting these circulating mesenchymal cells.
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Affiliation(s)
- Sarah M Williams
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO, USA
| | - Lucy Golden-Mason
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Colorado Denver, Aurora, CO, USA
| | - Bradley S Ferguson
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO, USA
| | - Katherine B Schuetze
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO, USA
| | - Maria A Cavasin
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO, USA
| | - Kim Demos-Davies
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO, USA
| | - Michael E Yeager
- Department of Pediatrics, Division of Pulmonary and Critical Care Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Kurt R Stenmark
- Department of Pediatrics, Division of Pulmonary and Critical Care Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Timothy A McKinsey
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO, USA.
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Onitsuka K, Ide T, Arai S, Hata Y, Murayama Y, Hosokawa K, Sakamoto T, Tobushi T, Sakamoto K, Fujino T, Sunagawa K. Cardiac phase-targeted dynamic load on left ventricle differentially regulates phase-sensitive gene expressions and pathway activation. J Mol Cell Cardiol 2013; 64:30-8. [PMID: 24004468 DOI: 10.1016/j.yjmcc.2013.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 08/07/2013] [Accepted: 08/26/2013] [Indexed: 12/15/2022]
Abstract
The heart has remarkable capacity to adapt to mechanical load and to dramatically change its phenotype. The mechanism underlying such diverse phenotypic adaptations remains unknown. Since systolic overload induces wall thickening, while diastolic overload induces chamber enlargement, we hypothesized that cardiac phase-sensitive mechanisms govern the adaptation. We inserted a balloon into the left ventricle (LV) of a Langendorff perfused rat heart, and controlled LV volume (LVV) using a high performance servo-pump. We created isolated phasic systolic overload (SO) by isovolumic contraction (peak LV pressure >170mmHg) at unstressed diastolic LVV [end-diastolic pressure (EDP)=0mmHg]. We also created pure phasic diastolic overload (DO) by increasing diastolic LVV until EDP >40mmHg and unloading completely in systole. After 3hours under each condition, the myocardium was analyzed using DNA microarray. Gene expressions under SO and DO conditions were compared against unloaded control condition using gene ontology and pathway analysis (n=4 each). SO upregulated proliferation-related genes, whereas DO upregulated fibrosis-related genes (P<10(-5)). Both SO and DO upregulated genes related functionally to cardiac hypertrophy, although the gene profiles were totally different. Upstream regulators confirmed by Western blot indicated that SO activated extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase, and Ca(2+)/calmodulin-dependent protein kinase II (3.2-, 2.0-, and 4.7-fold versus control, P<0.05, n=5), whereas DO activated p38 (2.9-fold, P<0.01), which was consistent with the downstream gene expressions. In conclusion, pure isolated systolic and diastolic overload permits elucidation of cardiac phase-sensitive gene regulation. The genomic responses indicate that mechanisms governing the cardiac phase-sensitive adaptations are different.
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Affiliation(s)
- Ken Onitsuka
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Vikhlyantsev IM, Podlubnaya ZA. New titin (connectin) isoforms and their functional role in striated muscles of mammals: facts and suppositions. BIOCHEMISTRY (MOSCOW) 2013; 77:1515-35. [PMID: 23379526 DOI: 10.1134/s0006297912130093] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This review summarizes results of our studies on titin isoform composition in vertebrate striated muscles under normal conditions, during hibernation, real and simulated microgravity, and under pathological conditions (stiff-person syndrome, post-apoplectic spasticity, dilated cardiomyopathy, cardiac hypertrophy). Experimental evidence for the existence in mammalian striated muscles of higher molecular weight isoforms of titin (NT-isoforms) in addition to the known N2A-, N2BA-, and N2B-titin isoforms was obtained. Comparative studies of changes in titin isoform composition and structure-functional properties of human and animal striated muscles during adaptive and pathological processes led to a conclusion about the key role of NT-isoforms of titin in maintenance of sarcomere structure and contractile function of these muscles.
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Affiliation(s)
- I M Vikhlyantsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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