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Bell KM, Brown AT, Van Houten SK, Blice-Baum AC, Kronert WA, Loya AK, Camillo JRT, Cammarato A, Corr DT, Bernstein SI, Swank DM. A Drosophila cardiac myosin increases jump muscle stretch activation and shortening deactivation. Biophys J 2025; 124:651-666. [PMID: 39799399 PMCID: PMC11900181 DOI: 10.1016/j.bpj.2025.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2024] [Revised: 12/06/2024] [Accepted: 01/08/2025] [Indexed: 01/15/2025] Open
Abstract
Stretch activation (SA), a delayed increase in force production after rapid muscle lengthening, is critical to the function of vertebrate cardiac muscle and insect asynchronous indirect flight muscle. SA enables or increases power generation in muscle types used in a cyclical manner. Recently, myosin isoform expression has been implicated as a mechanism for varying the amplitude of SA in some muscle types. For instance, we found that expressing a larval Drosophila myosin isoform in a muscle type with minimal SA, the Drosophila jump muscle, substantially increased SA amplitude and enabled positive cyclical power generation. To test whether other myosin isoforms could increase SA amplitude and whether the Drosophila heart benefits from SA, we identified two Drosophila cardiac myosin isoforms, CardM1 and CardM2, and expressed them in Drosophila jump muscle. CardM1, CardM2, and control jump muscle fibers all displayed the characteristic phase 3 of SA, with CardM2 SA amplitude ∼60% greater than that of CardM1 and control fibers. Increasing [Pi] from 0 to 16 mM increased CardM2 SA tension amplitude by 74%, yet had minimal or no effect on CardM1 or control muscle SA amplitude. CardM2 displayed the most prominent phase 3 dip when we induced shortening deactivation, a delayed decrease in force after muscle shortening. The magnitude of CardM2 shortening deactivation tension was ∼50% greater than control or CardM1 fibers. This, along with its greater stretch-activated tension, caused CardM2 to be the only isoform to produce positive power when its fiber length was sinusoidally oscillated. The results support our hypotheses that some myosin isoforms enable greater SA tension levels and suggest that the Drosophila heart is benefiting from SA and shortening deactivation in a manner similar to vertebrate hearts.
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Affiliation(s)
- Kaylyn M Bell
- Department of Biological Sciences & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Alon T Brown
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Sarah K Van Houten
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Anna C Blice-Baum
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - William A Kronert
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, California
| | - Amy K Loya
- Department of Electrical, Computer, and Biomedical Engineering Union College, Schenectady, New York
| | - Jared Rafael T Camillo
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, California
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - David T Corr
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York; Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, New York
| | - Sanford I Bernstein
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, California
| | - Douglas M Swank
- Department of Biological Sciences & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York; Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York.
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Leite L, Matos P, Leon-Justel A, Espírito-Santo C, Rodríguez-Padial L, Rodrigues F, Orozco D, Redon J. High sensitivity troponins: A potential biomarkers of cardiovascular risk for primary prevention. Front Cardiovasc Med 2022; 9:1054959. [PMID: 36531726 PMCID: PMC9748104 DOI: 10.3389/fcvm.2022.1054959] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/14/2022] [Indexed: 03/07/2024] Open
Abstract
There have been several approaches to building charts for CV risk, all of which have both strengths and limitations. Identifying early organ damage provides relevant information and should be included in risk charts, although the direct relationship with risk is imprecise, variability between operators at the time to assess, and low availability in some healthcare systems, limits its use. Biomarkers, like troponin (cTns) isoforms cTnI and cTnT, a cardiac specific myocyte injury marker, have the great advantage of being relatively reproducible, more readily accessible, and applicable to different populations. New and improved troponin assays have good analytical performance, can measure very low levels of circulating troponin, and have low intra individual variation, below 10 %. Several studies have analyzed the blood levels in healthy subjects and their predictive value for cardiovascular events in observational, prospective and post-hoc studies. All of them offered relevant information and shown that high sensitivity hs-cTnI has a place as an additional clinical marker to add to current charts, and it also reflects sex- and age-dependent differences. Although few more questions need to be answered before recommend cTnI for assessing CV risk in primary prevention, seems to be a potential strong marker to complement CV risk charts.
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Affiliation(s)
- Luis Leite
- Cardiology Department, Coimbra University Hospital, University of Coimbra, Coimbra, Portugal
| | - Pedro Matos
- APDP e Hospital CUF Infante Santo, Lisbon, Portugal
| | - Antonio Leon-Justel
- Department of Laboratory Medicine, Virgen Macarena University Hospital, Seville, Spain
| | | | | | | | - Domingo Orozco
- Department of Clinical Medicine, Miguel Hernández University, Elche, Spain
| | - Josep Redon
- INCLIVA Research Institute, University of Valencia, Valencia, Spain
- CIBERObn Institute of Health Carlos III, Madrid, Spain
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Through thick and thin: dual regulation of insect flight muscle and cardiac muscle compared. J Muscle Res Cell Motil 2019; 40:99-110. [PMID: 31292801 PMCID: PMC6726838 DOI: 10.1007/s10974-019-09536-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 07/02/2019] [Indexed: 01/15/2023]
Abstract
Both insect flight muscle and cardiac muscle contract rhythmically, but the way in which repetitive contractions are controlled is different in the two types of muscle. We have compared the flight muscle of the water bug, Lethocerus, with cardiac muscle. Both have relatively high resting elasticity and are activated by an increase in sarcomere length or a quick stretch. The larger response of flight muscle is attributed to the highly ordered lattice of thick and thin filaments and to an isoform of troponin C that has no exchangeable Ca2+-binding site. The Ca2+ sensitivity of cardiac muscle and flight muscle can be manipulated so that cardiac muscle responds to Ca2+ like flight muscle, and flight muscle responds like cardiac muscle, showing the malleability of regulation. The interactions of the subunits in flight muscle troponin are described; a model of the complex, using the structure of cardiac troponin as a template, shows an overall similarity of cardiac and flight muscle troponin complexes. The dual regulation by thick and thin filaments in skeletal and cardiac muscle is thought to operate in flight muscle. The structure of inhibited myosin heads folded back on the thick filament in relaxed Lethocerus fibres has not been seen in other species and may be an adaptation to the rapid contractions of flight muscle. A scheme for regulation by thick and thin filaments during oscillatory contraction is described. Cardiac and flight muscle have much in common, but the differing mechanical requirements mean that regulation by both thick and thin filaments is adapted to the particular muscle.
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Lan H, Hong X, Huang R, Lin X, Li Q, Li K, Zhou T. RNA interference-mediated knockdown and virus-induced suppression of Troponin C gene adversely affect the behavior or fitness of the green rice leafhopper, Nephotettix cincticeps. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2018; 97:e21438. [PMID: 29193300 DOI: 10.1002/arch.21438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The green rice leafhopper, Nephotettix cincticeps, is a major rice pest in Southeast Asia and Southern China. Novel control strategies must be explored to control the rice pest. Behavior or fitness regulation of insect by modulating the Troponin C (TnC) may be a novel strategy in the comprehensive management of the insect pest. However, characterizations and functions of TnC, especially regarding effect of its RNA interference-mediated gene knockdown on the behavior or fitness of N. cincticeps remain unknown. Here, we successfully cloned and characterized TnC gene from N. cincticeps (Nc-TnC). We demonstrated that Nc-TnC ubiquitously transcribed at all development stages and special tissues in adult insects, with relative higher levels at the adult stage and in the intestinal canal. Microinjection- or oral membrane feeding-based transient knockdown of Nc-TnC adversely affected the performance or fitness, such as the decreased survival, feeding capacity, weight, and fecundity of N. cincticeps. Furthermore, we revealed that the expression of Nc-TnC was suppressed by its interaction with rice dwarf virus-encoded nonstructural protein 10, which ultimately affected detrimentally the corresponding parameters of the performance or fitness of N. cincticeps. In conclusion, our data deepen understanding of Nc-TnC functions during the development of and viral infection in N. cincticeps. It imply Nc-TnC may serve as a potential target for N. cincticeps control in future.
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Affiliation(s)
- Hanhong Lan
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Xiaojing Hong
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Ranran Huang
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Xin Lin
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Qinghuang Li
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Kaihui Li
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Tao Zhou
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
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