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Vahle B, Heilmann L, Schauer A, Augstein A, Jarabo MEP, Barthel P, Mangner N, Labeit S, Bowen TS, Linke A, Adams V. Modulation of Titin and Contraction-Regulating Proteins in a Rat Model of Heart Failure with Preserved Ejection Fraction: Limb vs. Diaphragmatic Muscle. Int J Mol Sci 2024; 25:6618. [PMID: 38928324 PMCID: PMC11203682 DOI: 10.3390/ijms25126618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/12/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) is characterized by biomechanically dysfunctional cardiomyocytes. Underlying cellular changes include perturbed myocardial titin expression and titin hypophosphorylation leading to titin filament stiffening. Beside these well-studied alterations at the cardiomyocyte level, exercise intolerance is another hallmark of HFpEF caused by molecular alterations in skeletal muscle (SKM). Currently, there is a lack of data regarding titin modulation in the SKM of HFpEF. Therefore, the aim of the present study was to analyze molecular alterations in limb SKM (tibialis anterior (TA)) and in the diaphragm (Dia), as a more central SKM, with a focus on titin, titin phosphorylation, and contraction-regulating proteins. This study was performed with muscle tissue, obtained from 32-week old female ZSF-1 rats, an established a HFpEF rat model. Our results showed a hyperphosphorylation of titin in limb SKM, based on enhanced phosphorylation at the PEVK region, which is known to lead to titin filament stiffening. This hyperphosphorylation could be reversed by high-intensity interval training (HIIT). Additionally, a negative correlation occurring between the phosphorylation state of titin and the muscle force in the limb SKM was evident. For the Dia, no alterations in the phosphorylation state of titin could be detected. Supported by data of previous studies, this suggests an exercise effect of the Dia in HFpEF. Regarding the expression of contraction regulating proteins, significant differences between Dia and limb SKM could be detected, supporting muscle atrophy and dysfunction in limb SKM, but not in the Dia. Altogether, these data suggest a correlation between titin stiffening and the appearance of exercise intolerance in HFpEF, as well as a differential regulation between different SKM groups.
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Affiliation(s)
- Beatrice Vahle
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Leonard Heilmann
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Antje Schauer
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Antje Augstein
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Maria-Elisa Prieto Jarabo
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Peggy Barthel
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Norman Mangner
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Siegfried Labeit
- DZHK Partner Site Mannheim-Heidelberg, Medical Faculty Mannheim, University of Heidelberg, 68169 Mannheim, Germany;
- Myomedix GmbH, 69151 Neckargemünd, Germany
| | - T. Scott Bowen
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK;
| | - Axel Linke
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
| | - Volker Adams
- Heart Center Dresden, Laboratory of Molecular and Experimental Cardiology, TU Dresden, 01307 Dresden, Germany; (B.V.); (L.H.); (A.S.); (A.A.); (M.-E.P.J.); (P.B.); (N.M.); (A.L.)
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Wohlann T, Warneke K, Kalder V, Behm DG, Schmidt T, Schiemann S. Influence of 8-weeks of supervised static stretching or resistance training of pectoral major muscles on maximal strength, muscle thickness and range of motion. Eur J Appl Physiol 2024; 124:1885-1893. [PMID: 38240811 PMCID: PMC11129965 DOI: 10.1007/s00421-023-05413-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 12/29/2023] [Indexed: 05/28/2024]
Abstract
OBJECTIVES Current research suggests static stretch-induced maximal strength increases and muscle hypertrophy with potential to substitute resistance-training routines. However, most studies investigated the plantar flexors. This study explored the effects of a static stretching program on maximal strength, hypertrophy and flexibility of the pectoralis major and compared the effects with those of traditional resistance training. METHODS Eighty-one (81) active participants were allocated to either a static stretching, strength-training or control group. Pectoralis stretching was applied 15 min/day, 4 days per week for 8 weeks, while resistance training trained 3 days per week, 5 × 12 repetitions. RESULTS There was an increase in all parameters (strength: p < 0.001, ƞ2 = 0.313, muscle thickness: p < 0.001, ƞ2 = 0.157-0.264, flexibility: p < 0.001, ƞ2 = 0.316) and a time*group interaction (strength: p = 0.001, ƞ2 = 0.154, muscle thickness: p = 0.008-0.001, ƞ2 = 0.117-0.173, flexibility: p < 0.001, ƞ2 = 0.267). Post-hoc testing showed no difference between both intervention groups regarding maximal strength and muscle thickness (p = 0.905-0.983, d = 0.036-0.087), while flexibility increased in the stretching group (p = 0.001, d = 0.789). CONCLUSION Stretching showed increases in maximal strength and hypertrophy, which were comparable with commonly used resistance training. Based on current literature, the influence of mechanical tension as the underlying mechanism is discussed. Furthermore, as equipment and comparatively long stretching durations are requested to induce meaningful strength increases in recreationally active participants, practical application seems limited to special circumstances.
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Affiliation(s)
- Tim Wohlann
- Institute for Exercise, Sport and Health, Leuphana University, Lüneburg, Germany.
- Institute of Sport Science, University of Oldenburg, Oldenburg, Germany.
| | - Konstantin Warneke
- Institute of Sport Science, Alpen-Adria-University Klagenfurt, Klagenfurt Am Wörthersee, Austria
| | - Vincent Kalder
- Institute of Sport Science, University of Oldenburg, Oldenburg, Germany
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Tobias Schmidt
- Department of Sport Science, Medical School Hamburg, Hamburg, Germany
| | - Stephan Schiemann
- Institute for Exercise, Sport and Health, Leuphana University, Lüneburg, Germany
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Warneke K, Behm DG, Alizadeh S, Hillebrecht M, Konrad A, Wirth K. Discussing Conflicting Explanatory Approaches in Flexibility Training Under Consideration of Physiology: A Narrative Review. Sports Med 2024:10.1007/s40279-024-02043-y. [PMID: 38819597 DOI: 10.1007/s40279-024-02043-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 06/01/2024]
Abstract
The mechanisms underlying range of motion enhancements via flexibility training discussed in the literature show high heterogeneity in research methodology and study findings. In addition, scientific conclusions are mostly based on functional observations while studies considering the underlying physiology are less common. However, understanding the underlying mechanisms that contribute to an improved range of motion through stretching is crucial for conducting comparable studies with sound designs, optimising training routines and accurately interpreting resulting outcomes. While there seems to be no evidence to attribute acute range of motion increases as well as changes in muscle and tendon stiffness and pain perception specifically to stretching or foam rolling, the role of general warm-up effects is discussed in this paper. Additionally, the role of mechanical tension applied to greater muscle lengths for range of motion improvement will be discussed. Thus, it is suggested that physical training stressors can be seen as external stimuli that control gene expression via the targeted stimulation of transcription factors, leading to structural adaptations due to enhanced protein synthesis. Hence, the possible role of serial sarcomerogenesis in altering pain perception, reducing muscle stiffness and passive torque, or changes in the optimal joint angle for force development is considered as well as alternative interventions with a potential impact on anabolic pathways. As there are limited possibilities to directly measure serial sarcomere number, longitudinal muscle hypertrophy remains without direct evidence. The available literature does not demonstrate the necessity of only using specific flexibility training routines such as stretching to enhance acute or chronic range of motion.
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Affiliation(s)
- Konstantin Warneke
- Institute of Human Movement Science, Sport and Health, University of Graz, Graz, Austria.
- Department of Movement Sciences, Institute of Sport Science, University of Klagenfurt, Universitatsstraße 65, 9020, Klagenfurt Am Wörthersee, Austria.
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Shahab Alizadeh
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
- Human Performance Lab, Department of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Martin Hillebrecht
- University Sports Center, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Andreas Konrad
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
- University Sports Center, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Klaus Wirth
- University of Applied Sciences Wiener Neustadt, Vienna, Austria
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Belghith K, Zidi M, Fedele JM, Bou-Serhal R, Maktouf W. Quantifying Plantar Flexor Muscles Stiffness During Passive and Active Force Generation Using Shear Wave Elastography in Individuals With Chronic Stroke. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:735-742. [PMID: 38378402 DOI: 10.1016/j.ultrasmedbio.2024.01.072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/24/2024] [Accepted: 01/30/2024] [Indexed: 02/22/2024]
Abstract
OBJECTIVES This study aims to investigate the mechanical properties of paretic and healthy plantar flexor muscles and assesses the spatial distribution of stiffness between the gastrocnemius medialis (GM) and lateralis (GL) during active force generation. METHODS Shear wave elastography measurements were conducted on a control group (CNT, n=14; age=59.9±10.6 years; BMI=24.5±2.5 kg/m2) and a stroke survivor group (SSG, n=14; age=63.2±9.6 years; BMI=23.2±2.8 kg/m2). Shear modulus within the GM and GL was obtained during passive ankle mobilization at various angles of dorsiflexion (P0 =0°; P1=10°; P2=20°; P3=-20° and P4=-30°) and during different levels (30%, 50%, 70%, 100%) of maximal voluntary contraction (MVC). Muscle activations of GM, GL, soleus and tibialis anterior were also evaluated. RESULTS The results revealed a significant increase in passive stiffness within the paretic plantar flexor muscles under high tension during passive mobilization (p<0.05). Yet, during submaximal and maximal MVC, the paretic plantar flexors exhibited decreased active stiffness levels (p<0.05). A notable discrepancy was found between the stiffness of the GM and GL, with the GM demonstrating greater stiffness from 0° of dorsiflexion in the SSG (p<0.05), and from 10° of dorsiflexion in the CNT (p<0.05). No significant difference in stiffness was observed between the GM and GL muscles during active condition. CONCLUSION Stroke affects the mechanical properties differently depending on the state of muscle activation. Notably, the distribution of stiffness among synergistic plantar flexor muscles varied in passive condition, while remaining consistent in active condition.
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Affiliation(s)
- Kalthoum Belghith
- Bioengineering, Tissues and Neuroplasticity, UR 7377, University of Paris-Est Creteil, Faculty of Health/EPISEN, Creteil, France; CLINEA group, Clinique du Parc de Belleville, Paris, France
| | - Mustapha Zidi
- Bioengineering, Tissues and Neuroplasticity, UR 7377, University of Paris-Est Creteil, Faculty of Health/EPISEN, Creteil, France
| | | | | | - Wael Maktouf
- Bioengineering, Tissues and Neuroplasticity, UR 7377, University of Paris-Est Creteil, Faculty of Health/EPISEN, Creteil, France.
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Douglas CM, Bird JE, Kopinke D, Esser KA. An optimized approach to study nanoscale sarcomere structure utilizing super-resolution microscopy with nanobodies. PLoS One 2024; 19:e0300348. [PMID: 38687705 PMCID: PMC11060602 DOI: 10.1371/journal.pone.0300348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/23/2024] [Indexed: 05/02/2024] Open
Abstract
The sarcomere is the fundamental contractile unit in skeletal muscle, and the regularity of its structure is critical for function. Emerging data demonstrates that nanoscale changes to the regularity of sarcomere structure can affect the overall function of the protein dense ~2μm sarcomere. Further, sarcomere structure is implicated in many clinical conditions of muscle weakness. However, our understanding of how sarcomere structure changes in disease, especially at the nanoscale, has been limited in part due to the inability to robustly detect and measure at sub-sarcomere resolution. We optimized several methodological steps and developed a robust pipeline to analyze sarcomere structure using structured illumination super-resolution microscopy in conjunction with commercially-available and fluorescently-conjugated Variable Heavy-Chain only fragment secondary antibodies (nanobodies), and achieved a significant increase in resolution of z-disc width (353nm vs. 62nm) compared to confocal microscopy. The combination of these methods provides a unique approach to probe sarcomere protein localization at the nanoscale and may prove advantageous for analysis of other cellular structures.
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Affiliation(s)
- Collin M. Douglas
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States of America
| | - Jonathan E. Bird
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Daniel Kopinke
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Karyn A. Esser
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States of America
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Warneke K, Lohmann LH, Behm DG, Wirth K, Keiner M, Schiemann S, Wilke J. Effects of Chronic Static Stretching on Maximal Strength and Muscle Hypertrophy: A Systematic Review and Meta-Analysis with Meta-Regression. SPORTS MEDICINE - OPEN 2024; 10:45. [PMID: 38637473 PMCID: PMC11026323 DOI: 10.1186/s40798-024-00706-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 03/26/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Increases in maximal strength and muscle volume represent central aims of training interventions. Recent research suggested that the chronic application of stretch may be effective in inducing hypertrophy. The present systematic review therefore aimed to syntheisize the evidence on changes of strength and muscle volume following chronic static stretching. METHODS Three data bases were sceened to conduct a systematic review with meta-analysis. Studies using randomized, controlled trials with longitudinal (≥ 2 weeks) design, investigating strength and muscle volume following static stretching in humans, were included. Study quality was rated by two examiners using the PEDro scale. RESULTS A total of 42 studies with 1318 cumulative participants were identified. Meta-analyses using robust variance estimation showed small stretch-mediated maximal strength increases (d = 0.30 p < 0.001) with stretching duration and intervention time as significant moderators. Including all studies, stretching induced small magnitude, but significant hypertrophy effects (d = 0.20). Longer stretching durations and intervention periods as well as higher training frequencies revealed small (d = 0.26-0.28), but significant effects (p < 0.001-0.005), while lower dosage did not reach the level of significance (p = 0.13-0.39). CONCLUSIONS While of minor effectiveness, chronic static stretching represents a possible alternative to resistance training when aiming to improve strength and increase muscle size. As a dose-response relationship may exist, higher stretch durations and frequencies as well as long program durations should be further elaborated.
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Affiliation(s)
- Konstantin Warneke
- Institute of Human Movement Science, Sport and Health, University of Graz, Graz, Austria
- Department of Movement Sciences, University of Klagenfurt, Klagenfurt am Wörthersee, Austria
| | - Lars Hubertus Lohmann
- Department of Human Motion Science and Exercise Physiology, Friedrich Schiller University, 07743, Jena, Germany.
| | - David G Behm
- School of Human Kinetics and Recreation, Newfoundland and Labrador, Memorial University of Newfoundland, St. John's, Canada
| | - Klaus Wirth
- University of Applied Sciences Wiener Neustadt, Wiener Neustadt, Austria
| | - Michael Keiner
- Department of Sport Science, German University of Health & Sport, Ismaning, Germany
| | - Stephan Schiemann
- Institute of Exercise, Sport and Health, Leuphana University, Lüneburg, Germany
| | - Jan Wilke
- Department of Movement Sciences, University of Klagenfurt, Klagenfurt am Wörthersee, Austria
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Das S, Hilman MC, Yang F, Mourkioti F, Yang W, Cullen DK. Motor neurons and endothelial cells additively promote development and fusion of human iPSC-derived skeletal myocytes. Skelet Muscle 2024; 14:5. [PMID: 38454511 PMCID: PMC10921694 DOI: 10.1186/s13395-024-00336-4] [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: 08/08/2023] [Accepted: 01/30/2024] [Indexed: 03/09/2024] Open
Abstract
BACKGROUND Neurovascular cells have wide-ranging implications on skeletal muscle biology regulating myogenesis, maturation, and regeneration. Although several in vitro studies have investigated how motor neurons and endothelial cells interact with skeletal myocytes independently, there is limited knowledge about the combined effect of neural and vascular cells on muscle maturation and development. METHODS Here, we report a triculture system comprising human-induced pluripotent stem cell (iPSC)-derived skeletal myocytes, human iPSC-derived motor neurons, and primary human endothelial cells maintained under controlled media conditions. Briefly, iPSCs were differentiated to generate skeletal muscle progenitor cells (SMPCs). These SMPCs were seeded at a density of 5 × 104 cells/well in 12-well plates and allowed to differentiate for 7 days before adding iPSC-derived motor neurons at a concentration of 0.5 × 104 cells/well. The neuromuscular coculture was maintained for another 7 days in coculture media before addition of primary human umbilical vein endothelial cells (HUVEC) also at 0.5 × 104 cells/well. The triculture was maintained for another 7 days in triculture media comprising equal portions of muscle differentiation media, coculture media, and vascular media. Extensive morphological, genetic, and molecular characterization was performed to understand the combined and individual effects of neural and vascular cells on skeletal muscle maturation. RESULTS We observed that motor neurons independently promoted myofiber fusion, upregulated neuromuscular junction genes, and maintained a molecular niche supportive of muscle maturation. Endothelial cells independently did not support myofiber fusion and downregulated expression of LRP4 but did promote expression of type II specific myosin isoforms. However, neurovascular cells in combination exhibited additive increases in myofiber fusion and length, enhanced production of Agrin, along with upregulation of several key genes like MUSK, RAPSYN, DOK-7, and SLC2A4. Interestingly, more divergent effects were observed in expression of genes like MYH8, MYH1, MYH2, MYH4, and LRP4 and secretion of key molecular factors like amphiregulin and IGFBP-4. CONCLUSIONS Neurovascular cells when cultured in combination with skeletal myocytes promoted myocyte fusion with concomitant increase in expression of various neuromuscular genes. This triculture system may be used to gain a deeper understanding of the effects of the neurovascular niche on skeletal muscle biology and pathophysiology.
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Affiliation(s)
- Suradip Das
- Department of Neurosurgery, Center for Brain Injury & Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, 19104, USA.
| | - Melanie C Hilman
- Department of Neurosurgery, Center for Brain Injury & Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, 19104, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Feikun Yang
- Department of Medicine, Penn Institute for Regenerative Medicine, Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Foteini Mourkioti
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Musculoskeletal Program, Penn Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Wenli Yang
- Department of Medicine, Penn Institute for Regenerative Medicine, Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - D Kacy Cullen
- Department of Neurosurgery, Center for Brain Injury & Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, 19104, USA.
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.
- Musculoskeletal Program, Penn Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Carlassara M, Khorramnejad A, Oker H, Bahrami R, Lozada-Chávez AN, Mancini MV, Quaranta S, Body MJA, Lahondère C, Bonizzoni M. Population-specific responses to developmental temperature in the arboviral vector Aedes albopictus: Implications for climate change. GLOBAL CHANGE BIOLOGY 2024; 30:e17226. [PMID: 38454541 DOI: 10.1111/gcb.17226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/09/2024]
Abstract
The increase of environmental temperature due to current global warming is not only favouring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which the effects of developmental temperatures extend across developmental stages and their inter-stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector, to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome and Wolbachia prevalence in laboratory-reared populations originally collected from either temperate or tropical regions. We show that hatchability, larval and pupal viability and developmental speed are strongly influenced by temperature, and these effects extend to wing length, body mass, longevity and content of water, protein and lipids in adults in a population-specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Wolbachia density was generally lower in adult mosquitoes reared at 18°C than at other tested temperatures, and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450 and heat shock proteins) in mosquitoes reared at both 18 and 32°C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32°C, and the absence of isomorphy in the relationship between developmental stages and temperature in the laboratory population deriving from larvae collected in northern Italy. Altogether, these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact.
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Affiliation(s)
- Martina Carlassara
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Ayda Khorramnejad
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Helen Oker
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Romina Bahrami
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | | | | | - Stefano Quaranta
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Mélanie J A Body
- Department of Horticulture, Michigan State University, East Lansing, Michigan, USA
| | - Chloé Lahondère
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
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Pimenta R, Correia JP, Vaz JR, Veloso AP, Herzog W. Changes in passive and active hamstrings shear modulus are not related after a warmup protocol. J Biomech 2024; 163:111957. [PMID: 38266532 DOI: 10.1016/j.jbiomech.2024.111957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/10/2024] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
This study aimed to determine whether changes in hamstrings passive and active shear modulus after a warmup protocol are correlated. Twenty males without a history of hamstring strain injury participated. Muscle shear modulus was assessed using ultrasound-based shear wave elastography at rest and during isometric contractions at 20% of maximal voluntary isometric effort before and immediately after a warmup protocol. Changes in passive shear modulus did not seem to be associated with changes in active shear modulus. The results of this study suggest that changes in passive and active hamstring shear modulus are not associated after a standardized warmup intervention.
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Affiliation(s)
- Ricardo Pimenta
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Cruz Quebrada Dafundo, Portugal; Research Center of the Polytechnic Institute of Maia (N2i), Maia Polytechnic Institute (IPMAIA),Castêlo da Maia, 4475-690 Maia, Portugal; Futebol Clube Famalicão - Futebol SAD, Department of Rehabilitation and Performance, Famalicão, Portugal.
| | - José P Correia
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Cruz Quebrada Dafundo, Portugal
| | - João R Vaz
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Cruz Quebrada Dafundo, Portugal; Egas Moniz - Cooperativa de Ensino Superior, Monte da Caparica, Portugal
| | - António P Veloso
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Cruz Quebrada Dafundo, Portugal
| | - Walter Herzog
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
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Martinez-Martin I, Crousilles A, Ochoa JP, Velazquez-Carreras D, Mortensen SA, Herrero-Galan E, Delgado J, Dominguez F, Garcia-Pavia P, de Sancho D, Wilmanns M, Alegre-Cebollada J. Titin domains with reduced core hydrophobicity cause dilated cardiomyopathy. Cell Rep 2023; 42:113490. [PMID: 38052212 DOI: 10.1016/j.celrep.2023.113490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 12/07/2023] Open
Abstract
The underlying genetic defect in most cases of dilated cardiomyopathy (DCM), a common inherited heart disease, remains unknown. Intriguingly, many patients carry single missense variants of uncertain pathogenicity targeting the giant protein titin, a fundamental sarcomere component. To explore the deleterious potential of these variants, we first solved the wild-type and mutant crystal structures of I21, the titin domain targeted by pathogenic variant p.C3575S. Although both structures are remarkably similar, the reduced hydrophobicity of deeply buried position 3575 strongly destabilizes the mutant domain, a scenario supported by molecular dynamics simulations and by biochemical assays that show no disulfide involving C3575. Prompted by these observations, we have found that thousands of similar hydrophobicity-reducing variants associate specifically with DCM. Hence, our results imply that titin domain destabilization causes DCM, a conceptual framework that not only informs pathogenicity assessment of gene variants but also points to therapeutic strategies counterbalancing protein destabilization.
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Affiliation(s)
- Ines Martinez-Martin
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain.
| | - Audrey Crousilles
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
| | - Juan Pablo Ochoa
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHIM, CIBERCV, 28222 Madrid, Spain; Health in Code, 15008 A Coruña, Spain
| | | | - Simon A Mortensen
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
| | - Elias Herrero-Galan
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Javier Delgado
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Fernando Dominguez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHIM, CIBERCV, 28222 Madrid, Spain
| | - Pablo Garcia-Pavia
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHIM, CIBERCV, 28222 Madrid, Spain
| | - David de Sancho
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia, Kimika Fakultatea, UPV/EHU, 20018 Donostia-San Sebastian, Euskadi, Spain; Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastian, Euskadi, Spain
| | - Matthias Wilmanns
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
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11
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Hughes DC, Goodman CA, Baehr LM, Gregorevic P, Bodine SC. A critical discussion on the relationship between E3 ubiquitin ligases, protein degradation, and skeletal muscle wasting: it's not that simple. Am J Physiol Cell Physiol 2023; 325:C1567-C1582. [PMID: 37955121 PMCID: PMC10861180 DOI: 10.1152/ajpcell.00457.2023] [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: 09/18/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
Ubiquitination is an important post-translational modification (PTM) for protein substrates, whereby ubiquitin is added to proteins through the coordinated activity of activating (E1), ubiquitin-conjugating (E2), and ubiquitin ligase (E3) enzymes. The E3s provide key functions in the recognition of specific protein substrates to be ubiquitinated and aid in determining their proteolytic or nonproteolytic fates, which has led to their study as indicators of altered cellular processes. MuRF1 and MAFbx/Atrogin-1 were two of the first E3 ubiquitin ligases identified as being upregulated in a range of different skeletal muscle atrophy models. Since their discovery, the expression of these E3 ubiquitin ligases has often been studied as a surrogate measure of changes to bulk protein degradation rates. However, emerging evidence has highlighted the dynamic and complex regulation of the ubiquitin proteasome system (UPS) in skeletal muscle and demonstrated that protein ubiquitination is not necessarily equivalent to protein degradation. These observations highlight the potential challenges of quantifying E3 ubiquitin ligases as markers of protein degradation rates or ubiquitin proteasome system (UPS) activation. This perspective examines the usefulness of monitoring E3 ubiquitin ligases for determining specific or bulk protein degradation rates in the settings of skeletal muscle atrophy. Specific questions that remain unanswered within the skeletal muscle atrophy field are also identified, to encourage the pursuit of new research that will be critical in moving forward our understanding of the molecular mechanisms that govern protein function and degradation in muscle.
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Affiliation(s)
- David C Hughes
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
| | - Craig A Goodman
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
| | - Leslie M Baehr
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
| | - Paul Gregorevic
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Neurology, The University of Washington School of Medicine, Seattle, Washington, United States
| | - Sue C Bodine
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
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12
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Shi J, Wada M. Effects of eccentric contraction on force enhancement in rat fast-twitch muscle. Physiol Rep 2023; 11:e15797. [PMID: 37731168 PMCID: PMC10511694 DOI: 10.14814/phy2.15797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 09/22/2023] Open
Abstract
The aim of this study was to elucidate the effects of eccentric contraction (ECC) on force enhancement in rat fast-twitch skeletal muscle. Gastrocnemius (GAS) muscles were subjected to 200 ECCs in situ by electrical stimulation. Immediately before and after the stimulation, isometric torque produced by ankle flexion was measured at an ankle angle of 90°. After the second torque measurement, the superficial regions of the muscles were dissected and subjected to biochemical and skinned fiber analysis. ECC did not induce changes in the amount of degraded titin. After ECC, isometric torques in the GAS muscles were markedly reduced, especially at low stimulation frequency. ECC increased passive torque in whole muscle and passive force in skinned fibers. Passive force enhancement and the ratio of passive force to the maximal Ca2+ -activated force, but not residual force enhancement, were augmented in the skinned fibers subjected to ECC. An ECC-induced increase in titin-based stiffness may contribute to the increased PFE. These results suggest that skeletal muscle is endowed with a force potentiation system that can attenuate ECC-induced force reductions.
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Affiliation(s)
- Jiayu Shi
- Faculty of Sports SciencesNingbo UniversityZhejiangChina
| | - Masanobu Wada
- Graduate School of Humanities and Social SciencesHiroshima UniversityHiroshimaJapan
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13
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Faria A, Gabriel R, Brás R, Moreira H, Soares M, Ditroilo M. Free-oscillation technique: The effect of the magnitude of the impulse applied on muscle and tendon stiffness around the ankle. PLoS One 2023; 18:e0286847. [PMID: 37327246 PMCID: PMC10275422 DOI: 10.1371/journal.pone.0286847] [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: 02/02/2023] [Accepted: 05/24/2023] [Indexed: 06/18/2023] Open
Abstract
The importance of the muscle-tendon complex in sport and for activities of everyday living is well recognised. The free oscillation technique is frequently used to determine the musculo-articular "apparent" stiffness (obtained from vertical ground reaction force) and other parameters. However, an in-depth understanding of the muscle-tendon complex can be gained by separating the muscle (soleus) and the tendon (Achilles tendon) components and studying the "true" stiffness for each of these components (by considering the ankle joint moment arms), which can be valuable in improving our understanding of training, injury prevention, and recovery programs. Hence, this study aimed to investigate if muscle and tendon stiffness (i.e., "true" stiffness) are similarly affected by different impulse magnitudes when using the free-oscillation technique. Three impulse magnitudes (impulse 1, 2 and 3), corresponding to peak forces of 100, 150 and 200 N, were used to estimate the stiffness of the ankle joint in 27 males, using multiple loads (10, 15, 20, 25, 30, 35, and 40 kg). A significant decrease (p < 0.0005) was found in musculo-articular "apparent" stiffness (29224 ± 5087 N.m-1; 27839 ± 4914 N.m-1; 26835 ± 4880 N.m-1) between impulses 1, 2 and 3 respectively, when loads were collapsed across groups. However, significant differences (p < 0.001) were only found between the median (Mdn) of impulse 1 (Mdn = 564.31 (kN/m)/kN) and 2 (Mdn = 468.88 (kN/m)/kN) and between impulse 1 (Mdn = 564.31 (kN/m)/kN) and 3 (Mdn = 422.19 (kN/m)/kN), for "true" muscle stiffness, but not for "true" tendon stiffness (Mdn = 197.35 kN/m; Mdn = 210.26 kN/m; Mdn = 201.60 kN/m). The results suggest that the musculo-articular "apparent" stiffness around the ankle joint is influenced by the magnitude of the impulse applied. Interestingly, this is driven by muscle stiffness, whereas tendon stiffness appears to be unaffected.
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Affiliation(s)
- Aurélio Faria
- Department of Sport Sciences, CIDESD, University of Beira Interior, Covilhã, Portugal
| | - Ronaldo Gabriel
- Department of Sport Sciences, Exercise and Health – CITAB, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - Rui Brás
- Department of Sport Sciences, CIDESD, University of Beira Interior, Covilhã, Portugal
| | - Helena Moreira
- Department of Sport Sciences, Exercise and Health - CIDESD, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - Márcio Soares
- Department of Sport Sciences, CIDESD, University of Beira Interior, Covilhã, Portugal
| | - Massimiliano Ditroilo
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
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14
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Tran DT, Tsai L. Effect of strain rates on the mechanical response of whole muscle bundle. J Biol Phys 2023; 49:257-267. [PMID: 37009944 PMCID: PMC10160262 DOI: 10.1007/s10867-023-09630-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/04/2023] [Indexed: 04/04/2023] Open
Abstract
Muscle injuries frequently happen during sports activities and exercise, which could have serious consequences if not diagnosed and treated promptly. This research aims to investigate the quasi-static and dynamic responses of over 30 fresh frog semitendinosus muscles utilizing Split Hopkinson Pressure Bars (SHPB) and a material testing system under strain rates between 0.001 ~ 200 s-1. To accommodate the special shape of muscle-tendon-bone samples, PLA clampers were produced by the 3D printer to properly hold and prevent slipping during the testing process. The mechanical characteristics of the whole muscle bundle, including Young's modulus and stress-strain curve, are illustrated at various strain rates. The findings showed that the muscle properties were sensitive to strain rate when under passive deformation. Both maximum stress and Young's modulus increased with the rise of strain rate, and modulus at 200 s-1 can be as high as 10 times compared with quasi-static conditions.
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Affiliation(s)
- Dat Trong Tran
- Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, No. 415 Sanmin District, 807618, Jiangong, Kaohsiung City, Taiwan
- School of Transportation Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Liren Tsai
- Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, No. 415 Sanmin District, 807618, Jiangong, Kaohsiung City, Taiwan.
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15
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Linke WA. Stretching the story of titin and muscle function. J Biomech 2023; 152:111553. [PMID: 36989971 DOI: 10.1016/j.jbiomech.2023.111553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/29/2023]
Abstract
The discovery of the giant protein titin, also known as connectin, dates almost half a century back. In this review, I recapitulate major advances in the discovery of the titin filaments and the recognition of their properties and function until today. I briefly discuss how our understanding of the layout and interactions of titin in muscle sarcomeres has evolved and review key facts about the titin sequence at the gene (TTN) and protein levels. I also touch upon properties of titin important for the stability of the contractile units and the assembly and maintenance of sarcomeric proteins. The greater part of my discussion centers around the mechanical function of titin in skeletal muscle. I cover milestones of research on titin's role in stretch-dependent passive tension development, recollect the reasons behind the enormous elastic diversity of titin, and provide an update on the molecular mechanisms of titin elasticity, details of which are emerging even now. I reflect on current knowledge of how muscle fibers behave mechanically if titin stiffness is removed and how titin stiffness can be dynamically regulated, such as by posttranslational modifications or calcium binding. Finally, I highlight novel and exciting, but still controversially discussed, insight into the role titin plays in active tension development, such as length-dependent activation and contraction from longer muscle lengths.
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Affiliation(s)
- Wolfgang A Linke
- Institute of Physiology II, University of Münster, Germany; Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Germany; German Centre for Cardiovascular Research, Berlin, Germany.
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16
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Araz M, Weidner S, Izzi F, Badri-Spröwitz A, Siebert T, Haeufle DFB. Muscle preflex response to perturbations in locomotion: In vitro experiments and simulations with realistic boundary conditions. Front Bioeng Biotechnol 2023; 11:1150170. [PMID: 37214305 PMCID: PMC10194126 DOI: 10.3389/fbioe.2023.1150170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/21/2023] [Indexed: 05/24/2023] Open
Abstract
Neuromuscular control loops feature substantial communication delays, but mammals run robustly even in the most adverse conditions. In vivo experiments and computer simulation results suggest that muscles' preflex-an immediate mechanical response to a perturbation-could be the critical contributor. Muscle preflexes act within a few milliseconds, an order of magnitude faster than neural reflexes. Their short-lasting action makes mechanical preflexes hard to quantify in vivo. Muscle models, on the other hand, require further improvement of their prediction accuracy during the non-standard conditions of perturbed locomotion. Our study aims to quantify the mechanical work done by muscles during the preflex phase (preflex work) and test their mechanical force modulation. We performed in vitro experiments with biological muscle fibers under physiological boundary conditions, which we determined in computer simulations of perturbed hopping. Our findings show that muscles initially resist impacts with a stereotypical stiffness response-identified as short-range stiffness-regardless of the exact perturbation condition. We then observe a velocity adaptation to the force related to the amount of perturbation similar to a damping response. The main contributor to the preflex work modulation is not the change in force due to a change in fiber stretch velocity (fiber damping characteristics) but the change in magnitude of the stretch due to the leg dynamics in the perturbed conditions. Our results confirm previous findings that muscle stiffness is activity-dependent and show that also damping characteristics are activity-dependent. These results indicate that neural control could tune the preflex properties of muscles in expectation of ground conditions leading to previously inexplicable neuromuscular adaptation speeds.
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Affiliation(s)
- Matthew Araz
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Sven Weidner
- Department of Motion and Exercise Science, Institute of Sport and Movement Science, University of Stuttgart, Stuttgart, Germany
| | - Fabio Izzi
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Dynamic Locomotion Group, Max Plank Institute for Intelligent Systems, Stuttgart, Germany
| | - Alexander Badri-Spröwitz
- Dynamic Locomotion Group, Max Plank Institute for Intelligent Systems, Stuttgart, Germany
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Tobias Siebert
- Department of Motion and Exercise Science, Institute of Sport and Movement Science, University of Stuttgart, Stuttgart, Germany
| | - Daniel F. B. Haeufle
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
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17
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Eccentric muscle contractions: from single muscle fibre to whole muscle mechanics. Pflugers Arch 2023; 475:421-435. [PMID: 36790515 PMCID: PMC10011336 DOI: 10.1007/s00424-023-02794-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/24/2023] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
Eccentric muscle loading encompasses several unique features compared to other types of contractions. These features include increased force, work, and performance at decreased oxygen consumption, reduced metabolic cost, improved energy efficiency, as well as decreased muscle activity. This review summarises explanatory approaches to long-standing questions in terms of muscular contraction dynamics and molecular and cellular mechanisms underlying eccentric muscle loading. Moreover, this article intends to underscore the functional link between sarcomeric components, emphasising the fundamental role of titin in skeletal muscle. The giant filament titin reveals versatile functions ranging from sarcomere organisation and maintenance, providing passive tension and elasticity, and operates as a mechanosensory and signalling platform. Structurally, titin consists of a viscoelastic spring segment that allows activation-dependent coupling to actin. This titin-actin interaction can explain linear force increases in active lengthening experiments in biological systems. A three-filament model of skeletal muscle force production (mediated by titin) is supposed to overcome significant deviations between experimental observations and predictions by the classic sliding-filament and cross-bridge theories. Taken together, this review intends to contribute to a more detailed understanding of overall muscle behaviour and force generation-from a microscopic sarcomere level to a macroscopic multi-joint muscle level-impacting muscle modelling, the understanding of muscle function, and disease.
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18
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Bernabei M, Lee SSM, Perreault EJ, Sandercock TG. Axial stress determines the velocity of shear wave propagation in passive but not active muscles in vivo. J Appl Physiol (1985) 2023; 134:941-950. [PMID: 36861673 PMCID: PMC10069958 DOI: 10.1152/japplphysiol.00125.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/03/2023] Open
Abstract
Ultrasound shear wave elastography can be used to characterize mechanical properties of unstressed tissue by measuring shear wave velocity (SWV), which increases with increasing tissue stiffness. Measurements of SWV have often been assumed to be directly related to the stiffness of muscle. Some have also used measures of SWV to estimate stress, since muscle stiffness and stress covary during active contractions, but few have considered the direct influence of muscle stress on SWV. Rather, it is often assumed that stress alters the material properties of muscle, and in turn, shear wave propagation. The objective of this study was to determine how well the theoretical dependency of SWV on stress can account for measured changes of SWV in passive and active muscles. Data were collected from six isoflurane-anesthetized cats; three soleus muscles and three medial gastrocnemius muscles. Muscle stress and stiffness were measured directly along with SWV. Measurements were made across a range of passively and actively generated stresses, obtained by varying muscle length and activation, which was controlled by stimulating the sciatic nerve. Our results show that SWV depends primarily on the stress in a passively stretched muscle. In contrast, the SWV in active muscle is higher than would be predicted by considering only stress, presumably due to activation-dependent changes in muscle stiffness. Our results demonstrate that while SWV is sensitive to changes in muscle stress and activation, there is not a unique relationship between SWV and either of these quantities when considered in isolation.NEW & NOTEWORTHY Ultrasound shear wave elastography may be an inexpensive way to measure muscle stress in passive muscle. Here, using a cat model we directly measured shear wave velocity (SWV), muscle stress, and muscle stiffness. Our results show that SWV depends primarily on the stress in a passively stretched muscle. In contrast, the SWV in active muscle is higher than would be predicted by considering only stress, presumably due to activation-dependent changes in muscle stiffness.
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Affiliation(s)
- Michel Bernabei
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
- Shirley Ryan Ability Lab, Chicago, Illinois, United States
| | - Sabrina S M Lee
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, Illinois, United States
| | - Eric J Perreault
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
- Shirley Ryan Ability Lab, Chicago, Illinois, United States
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois, United States
| | - Thomas G Sandercock
- Department of Neuroscience, Northwestern University, Chicago, Illinois, United States
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19
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Zhuang S, Liu Y, Gao S, Tan Y, Hong H, Luo Y. Mechanisms of fish protein degradation caused by grass carp spoilage bacteria: A bottom-up exploration from the molecular level, muscle microstructure level, to related quality changes. Food Chem 2023; 403:134309. [DOI: 10.1016/j.foodchem.2022.134309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 10/14/2022]
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20
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Andersen OE, Kristensen AM, Nielsen OB, Overgaard K. Force potentiation during eccentric contractions in rat skeletal muscle. J Appl Physiol (1985) 2023; 134:777-785. [PMID: 36759160 DOI: 10.1152/japplphysiol.00676.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Postactivation potentiation refers to an acute enhancement of contractile properties following muscle activity. Previously, the effects of prior muscle activation on eccentric force at tetanic activation frequencies have only been sparsely reported. This paper aimed to study acute activity-induced effects on eccentric force of slow and fast-twitch muscles and characterize them in relation to postactivation potentiation. We elicited eccentric contractions in isolated rat extensor digitorum longus and soleus muscles by actively lengthening muscles at a constant velocity. We assessed contractile properties by measuring force over shortly interspaced, identical eccentric, and isometric contractions. We then analyzed stretch force, isometric peak force, rate of force development, and relaxation times. Finally, we compared the time courses for the development and cessation of changes in stretch force to known features of postactivation potentiation. In extensor digitorum longus, muscles stretch force consistently increased in a contraction-to-contraction manner by up to 49% [95% confidence interval (CI): 35-64%] whereas isometric peak force simultaneously showed minor declines (8%, 95% CI: 5-10%). The development and cessation of eccentric force potentiation coincided with the development of twitch potentiation and increases in rate of force development. In soleus muscles we found no consistent eccentric potentiation. Characterization of the increase in eccentric force revealed that force only increased in the very beginning of an active stretch. Eccentric force at tetanic activation frequencies potentiates substantially in extensor digitorum longus muscles over consecutive contractions with a time course coinciding with postactivation potentiation. Such eccentric potentiation may be important in sport performance.NEW & NOTEWORTHY Force during eccentric contractions can increase to a magnitude that may have profound consequences for our understanding of skeletal muscle locomotion. This increase in eccentric force occurs over consecutive, shortly interspaced, tetanic contractions in rat extensor digitorum longus muscles-not in rat soleus muscles-and coincides with well-known traits of postactivation potentiation. Eccentric force potentiation may significantly enhance muscle performance in activities involving stretch-shortening cycles.
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Affiliation(s)
- Ole Emil Andersen
- Department of Public Health, Aarhus University, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University, Aarhus, Denmark
| | | | - Ole B Nielsen
- Department of Public Health, Aarhus University, Aarhus, Denmark
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21
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Dowling P, Gargan S, Swandulla D, Ohlendieck K. Fiber-Type Shifting in Sarcopenia of Old Age: Proteomic Profiling of the Contractile Apparatus of Skeletal Muscles. Int J Mol Sci 2023; 24:ijms24032415. [PMID: 36768735 PMCID: PMC9916839 DOI: 10.3390/ijms24032415] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
The progressive loss of skeletal muscle mass and concomitant reduction in contractile strength plays a central role in frailty syndrome. Age-related neuronal impairments are closely associated with sarcopenia in the elderly, which is characterized by severe muscular atrophy that can considerably lessen the overall quality of life at old age. Mass-spectrometry-based proteomic surveys of senescent human skeletal muscles, as well as animal models of sarcopenia, have decisively improved our understanding of the molecular and cellular consequences of muscular atrophy and associated fiber-type shifting during aging. This review outlines the mass spectrometric identification of proteome-wide changes in atrophying skeletal muscles, with a focus on contractile proteins as potential markers of changes in fiber-type distribution patterns. The observed trend of fast-to-slow transitions in individual human skeletal muscles during the aging process is most likely linked to a preferential susceptibility of fast-twitching muscle fibers to muscular atrophy. Studies with senescent animal models, including mostly aged rodent skeletal muscles, have confirmed fiber-type shifting. The proteomic analysis of fast versus slow isoforms of key contractile proteins, such as myosin heavy chains, myosin light chains, actins, troponins and tropomyosins, suggests them as suitable bioanalytical tools of fiber-type transitions during aging.
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Affiliation(s)
- Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
| | - Stephen Gargan
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
| | - Dieter Swandulla
- Institute of Physiology, University of Bonn, D53115 Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
- Correspondence: ; Tel.: +353-1-7083842
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22
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Beedle AEM, Garcia-Manyes S. The role of single protein elasticity in mechanobiology. NATURE REVIEWS. MATERIALS 2023; 8:10-24. [PMID: 37469679 PMCID: PMC7614781 DOI: 10.1038/s41578-022-00488-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 07/21/2023]
Abstract
In addition to biochemical signals and genetic considerations, mechanical forces are rapidly emerging as a master regulator of human physiology. Yet the molecular mechanisms that regulate force-induced functionalities across a wide range of scales, encompassing the cell, tissue or organ levels, are comparatively not so well understood. With the advent, development and refining of single molecule nanomechanical techniques, enabling to exquisitely probe the conformational dynamics of individual proteins under the effect of a calibrated force, we have begun to acquire a comprehensive knowledge on the rich plethora of physicochemical principles that regulate the elasticity of single proteins. Here we review the major advances underpinning our current understanding of how the elasticity of single proteins regulates mechanosensing and mechanotransduction. We discuss the present limitations and future challenges of such a prolific and burgeoning field.
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Affiliation(s)
- Amy EM Beedle
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute of Technology (BIST), 08028 Barcelona, Spain
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK
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23
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Khalilimeybodi A, Riaz M, Campbell SG, Omens JH, McCulloch AD, Qyang Y, Saucerman JJ. Signaling network model of cardiomyocyte morphological changes in familial cardiomyopathy. J Mol Cell Cardiol 2023; 174:1-14. [PMID: 36370475 PMCID: PMC10230857 DOI: 10.1016/j.yjmcc.2022.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 08/26/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022]
Abstract
Familial cardiomyopathy is a precursor of heart failure and sudden cardiac death. Over the past several decades, researchers have discovered numerous gene mutations primarily in sarcomeric and cytoskeletal proteins causing two different disease phenotypes: hypertrophic (HCM) and dilated (DCM) cardiomyopathies. However, molecular mechanisms linking genotype to phenotype remain unclear. Here, we employ a systems approach by integrating experimental findings from preclinical studies (e.g., murine data) into a cohesive signaling network to scrutinize genotype to phenotype mechanisms. We developed an HCM/DCM signaling network model utilizing a logic-based differential equations approach and evaluated model performance in predicting experimental data from four contexts (HCM, DCM, pressure overload, and volume overload). The model has an overall prediction accuracy of 83.8%, with higher accuracy in the HCM context (90%) than DCM (75%). Global sensitivity analysis identifies key signaling reactions, with calcium-mediated myofilament force development and calcium-calmodulin kinase signaling ranking the highest. A structural revision analysis indicates potential missing interactions that primarily control calcium regulatory proteins, increasing model prediction accuracy. Combination pharmacotherapy analysis suggests that downregulation of signaling components such as calcium, titin and its associated proteins, growth factor receptors, ERK1/2, and PI3K-AKT could inhibit myocyte growth in HCM. In experiments with patient-specific iPSC-derived cardiomyocytes (MLP-W4R;MYH7-R723C iPSC-CMs), combined inhibition of ERK1/2 and PI3K-AKT rescued the HCM phenotype, as predicted by the model. In DCM, PI3K-AKT-NFAT downregulation combined with upregulation of Ras/ERK1/2 or titin or Gq protein could ameliorate cardiomyocyte morphology. The model results suggest that HCM mutations that increase active force through elevated calcium sensitivity could increase ERK activity and decrease eccentricity through parallel growth factors, Gq-mediated, and titin pathways. Moreover, the model simulated the influence of existing medications on cardiac growth in HCM and DCM contexts. This HCM/DCM signaling model demonstrates utility in investigating genotype to phenotype mechanisms in familial cardiomyopathy.
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Affiliation(s)
- Ali Khalilimeybodi
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States of America
| | - Muhammad Riaz
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jeffrey H Omens
- Departments of Bioengineering and Medicine, University of California, San Diego, La Jolla, CA, United States of America
| | - Andrew D McCulloch
- Departments of Bioengineering and Medicine, University of California, San Diego, La Jolla, CA, United States of America
| | - Yibing Qyang
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, New Haven, CT, United States of America; Department of Pathology, Yale University, New Haven, CT, United States of America; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, United States of America
| | - Jeffrey J Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States of America; Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, United States of America.
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24
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Kukulage DSK, Matarage Don NNJ, Ahn YH. Emerging chemistry and biology in protein glutathionylation. Curr Opin Chem Biol 2022; 71:102221. [PMID: 36223700 PMCID: PMC9844265 DOI: 10.1016/j.cbpa.2022.102221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 01/27/2023]
Abstract
Protein S-glutathionylation serves a regulatory role in proteins and modulates distinct biological processes implicated in health and diseases. Despite challenges in analyzing the dynamic and reversible nature of S-glutathionylation, recent chemical and biological methods have significantly advanced the field of S-glutathionylation, culminating in selective identification and detection, structural motif analysis, and functional studies of S-glutathionylation. This review will highlight emerging studies of protein glutathionylation, beginning by introducing biochemical tools that enable mass spectrometric identification and live-cell imaging of S-glutathionylation. Next, it will spotlight recent examples of S-glutathionylation regulating physiology and inflammation. Lastly, we will feature two emerging lines of glutathionylation research in cryptic cysteine glutathionylation and protein C-glutathionylation.
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Affiliation(s)
| | | | - Young-Hoon Ahn
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
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25
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Thangadurai M, Ajith A, Budharaju H, Sethuraman S, Sundaramurthi D. Advances in electrospinning and 3D bioprinting strategies to enhance functional regeneration of skeletal muscle tissue. BIOMATERIALS ADVANCES 2022; 142:213135. [PMID: 36215745 DOI: 10.1016/j.bioadv.2022.213135] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/31/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Skeletal muscles are essential for body movement, and the loss of motor function due to volumetric muscle loss (VML) limits the mobility of patients. Current therapeutic approaches are insufficient to offer complete functional recovery of muscle damages. Tissue engineering provides viable ways to fabricate scaffolds to regenerate damaged tissues. Hence, tissue engineering options are explored to address existing challenges in the treatment options for muscle regeneration. Electrospinning is a widely employed fabrication technique to make muscle mimetic nanofibrous scaffolds for tissue regeneration. 3D bioprinting has also been utilized to fabricate muscle-like tissues in recent times. This review discusses the anatomy of skeletal muscle, defects, the healing process, and various treatment options for VML. Further, the advanced strategies in electrospinning of natural and synthetic polymers are discussed, along with the recent developments in the fabrication of hybrid scaffolds. Current approaches in 3D bioprinting of skeletal muscle tissues are outlined with special emphasis on the combination of electrospinning and 3D bioprinting towards the development of fully functional muscle constructs. Finally, the current challenges and future perspectives of these convergence techniques are discussed.
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Affiliation(s)
- Madhumithra Thangadurai
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, India
| | - Athulya Ajith
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, India
| | - Harshavardhan Budharaju
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, India
| | - Swaminathan Sethuraman
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, India
| | - Dhakshinamoorthy Sundaramurthi
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, India.
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26
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Choi C, Smalley JL, Lemons AHS, Ren Q, Bope CE, Dengler JS, Davies PA, Moss SJ. Analyzing the mechanisms that facilitate the subtype-specific assembly of γ-aminobutyric acid type A receptors. Front Mol Neurosci 2022; 15:1017404. [PMID: 36263376 PMCID: PMC9574402 DOI: 10.3389/fnmol.2022.1017404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 09/07/2022] [Indexed: 01/16/2023] Open
Abstract
Impaired inhibitory signaling underlies the pathophysiology of many neuropsychiatric and neurodevelopmental disorders including autism spectrum disorders and epilepsy. Neuronal inhibition is regulated by synaptic and extrasynaptic γ-aminobutyric acid type A receptors (GABA A Rs), which mediate phasic and tonic inhibition, respectively. These two GABA A R subtypes differ in their function, ligand sensitivity, and physiological properties. Importantly, they contain different α subunit isoforms: synaptic GABA A Rs contain the α1-3 subunits whereas extrasynaptic GABA A Rs contain the α4-6 subunits. While the subunit composition is critical for the distinct roles of synaptic and extrasynaptic GABA A R subtypes in inhibition, the molecular mechanism of the subtype-specific assembly has not been elucidated. To address this issue, we purified endogenous α1- and α4-containing GABA A Rs from adult murine forebrains and examined their subunit composition and interacting proteins using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and quantitative analysis. We found that the α1 and α4 subunits form separate populations of GABA A Rs and interact with distinct sets of binding proteins. We also discovered that the β3 subunit, which co-purifies with both the α1 and α4 subunits, has different levels of phosphorylation on serines 408 and 409 (S408/9) between the two receptor subtypes. To understand the role S408/9 plays in the assembly of α1- and α4-containing GABA A Rs, we examined the effects of S408/9A (alanine) knock-in mutation on the subunit composition of the two receptor subtypes using LC-MS/MS and quantitative analysis. We discovered that the S408/9A mutation results in the formation of novel α1α4-containing GABA A Rs. Moreover, in S408/9A mutants, the plasma membrane expression of the α4 subunit is increased whereas its retention in the endoplasmic reticulum is reduced. These findings suggest that S408/9 play a critical role in determining the subtype-specific assembly of GABA A Rs, and thus the efficacy of neuronal inhibition.
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Affiliation(s)
- Catherine Choi
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Joshua L. Smalley
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Abigail H. S. Lemons
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Qiu Ren
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Christopher E. Bope
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Jake S. Dengler
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Paul A. Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Stephen J. Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States,Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom,*Correspondence: Stephen J. Moss,
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27
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Shi J, Watanabe D, Wada M. Eccentric muscle contraction potentiates titin stiffness-related contractile properties in rat fast-twitch muscles. J Appl Physiol (1985) 2022; 133:710-720. [PMID: 35981734 DOI: 10.1152/japplphysiol.00327.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was conducted to examine the effects of an acute bout of eccentric muscle contraction (ECC) on titin stiffness-related contractile properties in rat fast-twitch skeletal muscles. Intact gastrocnemius muscles were electrically stimulated in situ to undergo 200-repeated ECCs. Immediately after cessation of the stimulation, the superficial regions of the muscles were dissected and subjected to biochemical and skinned fiber analyses. Small heat shock protein αB-crystallin in the muscle fraction enriched for myofibrillar proteins was increased by ECC. ECC resulted in an increase in the titin-based passive force. Protein kinase A-treatment decreased the passive force only in ECC-subjected but not in rested fibers. ECC decreased the maximum Ca2+-activated force at a sarcomere length (SL) of 2.4 μm and had no effect on myofibrillar-Ca2+ sensitivity at 2.6-μm SL. In both rested and ECC-subjected fibers, these two variables were higher at 3.0-μm SL than at 2.4- or 2.6-μm SL. The differences in the two variables between the short and long SLs were greater in ECC-subjected than in rested fibers. These results indicate that an acute bout of ECC potentiates titin-based passive force, maximum active force at long SLs, and length-dependent activation and suggest that this potentiation may resist muscle fatigue in the muscles of the exercising body.
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Affiliation(s)
- Jiayu Shi
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Masanobu Wada
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan.,Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
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28
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Kuo CW, Pratiwi FW, Liu YT, Chueh DY, Chen P. Revealing the nanometric structural changes in myocardial infarction models by time-lapse intravital imaging. Front Bioeng Biotechnol 2022; 10:935415. [PMID: 36051583 PMCID: PMC9424828 DOI: 10.3389/fbioe.2022.935415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
In the development of bioinspired nanomaterials for therapeutic applications, it is very important to validate the design of nanomaterials in the disease models. Therefore, it is desirable to visualize the change of the cells in the diseased site at the nanoscale. Heart diseases often start with structural, morphological, and functional alterations of cardiomyocyte components at the subcellular level. Here, we developed straightforward technique for long-term real-time intravital imaging of contracting hearts without the need of cardiac pacing and complex post processing images to understand the subcellular structural and dynamic changes in the myocardial infarction model. A two-photon microscope synchronized with electrocardiogram signals was used for long-term in vivo imaging of a contracting heart with subcellular resolution. We found that the structural and dynamic behaviors of organelles in cardiomyocytes closely correlated with heart function. In the myocardial infarction model, sarcomere shortening decreased from ∼15% (healthy) to ∼8% (diseased) as a result of impaired cardiac function, whereas the distances between sarcomeres increased by 100 nm (from 2.11 to 2.21 μm) in the diastolic state. In addition, T-tubule system regularity analysis revealed that T-tubule structures that were initially highly organized underwent significant remodeling. Morphological remodeling and changes in dynamic activity at the subcellular level are essential to maintain heart function after infarction in a heart disease model.
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Affiliation(s)
- Chiung Wen Kuo
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
| | | | - Yen-Ting Liu
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
| | - Di-Yen Chueh
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
| | - Peilin Chen
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
- Institute of Physics, Academia Sinica, Taipei, Taiwan
- *Correspondence: Peilin Chen,
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29
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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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30
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Stirnemann G. Molecular interpretation of single-molecule force spectroscopy experiments with computational approaches. Chem Commun (Camb) 2022; 58:7110-7119. [PMID: 35678696 DOI: 10.1039/d2cc01350a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single molecule force-spectroscopy techniques have granted access to unprecedented molecular-scale details about biochemical and biological mechanisms. However, the interpretation of the experimental data is often challenging. Computational and simulation approaches (all-atom steered MD simulations in particular) are key to provide molecular details about the associated mechanisms, to help test different hypotheses and to predict experimental results. In this review, particular recent efforts directed towards the molecular interpretation of single-molecule force spectroscopy experiments on proteins and protein-related systems (often in close collaboration with experimental groups) will be presented. These results will be discussed in the broader context of the field, highlighting the recent achievements and the ongoing challenges for computational biophysicists and biochemists. In particular, I will focus on the input gained from molecular simulations approaches to rationalize the origin of the unfolded protein elasticity and the protein conformational behavior under force, to understand how force denaturation differs from chemical, thermal or shear unfolding, and to unravel the molecular details of unfolding events for a variety of systems. I will also discuss the use of models based on Langevin dynamics on a 1-D free-energy surface to understand the effect of protein segmentation on the work exerted by a force, or, at the other end of the spectrum of computational techniques, how quantum calculations can help to understand the reactivity of disulfide bridges exposed to force.
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Affiliation(s)
- Guillaume Stirnemann
- CNRS Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique, PSL University, Université de Paris, 13 rue Pierre et Marie Curie, 75005, Paris, France.
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31
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The Possible Impact of COVID-19 on Respiratory Muscles Structure and Functions: A Literature Review. SUSTAINABILITY 2022. [DOI: 10.3390/su14127446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The impact of SARS-CoV-2 infection on respiratory muscle functions is an important area of recent enquiry. COVID-19 has effects on the respiratory muscles. The diaphragm muscle is perturbed indirectly due to the mechanical-ventilation-induced-disuse, but also by direct mechanisms linked with SARS-CoV-2 viral infection. In this sense, a deeper understanding of the possible links between COVID-19 and alterations in structure and functions of the respiratory muscles may increase the success rate of preventive and supportive strategies. Ultrasound imaging alongside respiratory muscle strength tests and pulmonary function assessment are valid approaches to the screening and monitoring of disease, for mild to severe patients. The aim of the present review is to highlight the current literature regarding the links between COVID-19 and respiratory muscle functions. We examine from the pathophysiological aspects of disease, up to approaches taken to monitor and rehabilitate diseased muscle. We hope this work will add to a greater understanding of the pathophysiology and disease management of respiratory muscle pathology subsequent to SARS-CoV-2 infection.
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32
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Weidner S, Tomalka A, Rode C, Siebert T. How velocity impacts eccentric force generation of fully activated skinned skeletal muscle fibers in long stretches. J Appl Physiol (1985) 2022; 133:223-233. [PMID: 35652830 DOI: 10.1152/japplphysiol.00735.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Eccentric muscle contractions are fundamental to everyday life. They occur markedly in jumping, running, and accidents. Following an initial force rise, stretching of a fully activated muscle can result in a phase of decreasing force ('Give') followed by force redevelopment. However, how the stretch velocity affects 'Give' and force redevelopment remains largely unknown. We investigated the force produced by fully activated single skinned fibers of rat extensor digitorum longus muscles during long stretches. Fibers were pulled from length .85 to 1.3 optimal fiber length at a rate of 1, 10 and 100% of the estimated maximum shortening velocity. 'Give' was absent in slow stretches. Medium and fast stretches yielded a clear 'Give'. After the initial force peak, forces decreased by 11.2% and 27.8% relative to the initial peak force before rising again. During the last half of the stretch (from 1.07 to 1.3 optimal fiber length, which is within the range of the expected descending limb of the force-length relationship), the linear force slope tripled from slow to medium stretch and increased further by 60% from medium to fast stretch. These results are compatible with forcible cross-bridge detachment and re-development of a cross-bridge distribution, and a viscoelastic titin contribution to fiber force. Accounting for these results can improve muscle models and predictions of multi-body simulations.
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Affiliation(s)
- Sven Weidner
- nstitute of Sport and Movement Science, Department of Motion and Exercise Science, University of Stuttgart, Stuttgart, Germany
| | - André Tomalka
- nstitute of Sport and Movement Science, Department of Motion and Exercise Science, University of Stuttgart, Stuttgart, Germany
| | - Christian Rode
- nstitute of Sport Science, Department of Biomechanics, University of Rostock, Rostock, Germany
| | - Tobias Siebert
- nstitute of Sport and Movement Science, Department of Motion and Exercise Science, University of Stuttgart, Stuttgart, Germany.,Stuttgart Center of Simulation Science, University of Stuttgart, Stuttgart, Germany
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33
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Herrero-Galán E, Martínez-Martín I, Sánchez-González C, Vicente N, Bonzón-Kulichenko E, Calvo E, Suay-Corredera C, Pricolo MR, Fernández-Trasancos Á, Velázquez-Carreras D, Careaga CB, Abdellatif M, Sedej S, Rainer PP, Giganti D, Pérez-Jiménez R, Vázquez J, Alegre-Cebollada J. Basal oxidation of conserved cysteines modulates cardiac titin stiffness and dynamics. Redox Biol 2022; 52:102306. [PMID: 35367810 PMCID: PMC8971355 DOI: 10.1016/j.redox.2022.102306] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 01/11/2023] Open
Abstract
Titin, as the main protein responsible for the passive stiffness of the sarcomere, plays a key role in diastolic function and is a determinant factor in the etiology of heart disease. Titin stiffness depends on unfolding and folding transitions of immunoglobulin-like (Ig) domains of the I-band, and recent studies have shown that oxidative modifications of cryptic cysteines belonging to these Ig domains modulate their mechanical properties in vitro. However, the relevance of this mode of titin mechanical modulation in vivo remains largely unknown. Here, we describe the high evolutionary conservation of titin mechanical cysteines and show that they are remarkably oxidized in murine cardiac tissue. Mass spectrometry analyses indicate a similar landscape of basal oxidation in murine and human myocardium. Monte Carlo simulations illustrate how disulfides and S-thiolations on these cysteines increase the dynamics of the protein at physiological forces, while enabling load- and isoform-dependent regulation of titin stiffness. Our results demonstrate the role of conserved cysteines in the modulation of titin mechanical properties in vivo and point to potential redox-based pathomechanisms in heart disease.
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Affiliation(s)
| | | | | | - Natalia Vicente
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Elena Bonzón-Kulichenko
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Enrique Calvo
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | | | | | | | | | | | | | - Simon Sedej
- Division of Cardiology, Medical University of Graz, Graz, Austria; Faculty of Medicine, University of Maribor, Maribor, Slovenia; BioTechMed Graz, Graz, Austria
| | - Peter P Rainer
- Division of Cardiology, Medical University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - David Giganti
- Department of Biochemistry & Molecular Pharmacology and Institute for Systems Genetics, NYU Langone Health, New York, NY, United States
| | - Raúl Pérez-Jiménez
- CIC NanoGUNE BRTA, San Sebastian, Spain; Ikerbasque Foundation for Science, Bilbao, Spain
| | - Jesús Vázquez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
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34
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Array Comparative Genomic Hybridisation and Droplet Digital PCR Uncover Recurrent Copy Number Variation of the TTN Segmental Duplication Region. Genes (Basel) 2022; 13:genes13050905. [PMID: 35627290 PMCID: PMC9142044 DOI: 10.3390/genes13050905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/13/2022] [Accepted: 05/17/2022] [Indexed: 02/04/2023] Open
Abstract
Intragenic segmental duplication regions are potential hotspots for recurrent copy number variation and possible pathogenic aberrations. Two large sarcomeric genes, nebulin and titin, both contain such segmental duplication regions. Using our custom Comparative Genomic Hybridisation array, we have previously shown that a gain or loss of more than one copy of the repeated block of the nebulin triplicate region constitutes a recessive pathogenic mutation. Using targeted array-CGH, similar copy number variants can be detected in the segmental duplication region of titin. Due to the limitations of the array-CGH methodology and the repetitiveness of the region, the exact copy numbers of the blocks could not be determined. Therefore, we developed complementary custom Droplet Digital PCR assays for the titin segmental duplication region to confirm true variation. Our combined methods show that the titin segmental duplication region is subject to recurrent copy number variation. Gains and losses were detected in samples from healthy individuals as well as in samples from patients with different muscle disorders. The copy number variation observed in our cohort is likely benign, but pathogenic copy number variants in the segmental duplication region of titin cannot be excluded. Further investigations are needed, however, this region should no longer be neglected in genetic analyses.
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Gil-Redondo JC, Weber A, Toca-Herrera JL. Measuring (biological) materials mechanics with atomic force microscopy. 3. Mechanical unfolding of biopolymers. Microsc Res Tech 2022; 85:3025-3036. [PMID: 35502131 PMCID: PMC9543778 DOI: 10.1002/jemt.24136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 11/28/2022]
Abstract
Biopolymers, such as polynucleotides, polypeptides and polysaccharides, are macromolecules that direct most of the functions in living beings. Studying the mechanical unfolding of biopolymers provides important information about their molecular elasticity and mechanical stability, as well as their energy landscape, which is especially important in proteins, since their three‐dimensional structure is essential for their correct activity. In this primer, we present how to study the mechanical properties of proteins with atomic force microscopy and how to obtain information about their stability and energetic landscape. In particular, we discuss the preparation of polyprotein constructs suitable for AFM single molecule force spectroscopy (SMFS), describe the parameters used in our force‐extension SMFS experiments and the models and equations employed in the analysis of the data. As a practical example, we show the effect of the temperature on the unfolding force, the distance to the transition state, the unfolding rate at zero force, the height of the transition state barrier, and the spring constant of the protein for a construct containing nine repeats of the I27 domain from the muscle protein titin.
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Affiliation(s)
- Juan Carlos Gil-Redondo
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
| | - Andreas Weber
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
| | - José L Toca-Herrera
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
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Nitric oxide and skeletal muscle contractile function. Nitric Oxide 2022; 122-123:54-61. [PMID: 35405336 PMCID: PMC10167965 DOI: 10.1016/j.niox.2022.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/23/2022] [Accepted: 04/05/2022] [Indexed: 11/21/2022]
Abstract
Nitric oxide (NO) is complex modulator of skeletal muscle contractile function, capable of increasing or decreasing force and power output depending on multiple factors. This review explores the effects and potential mechanisms for modulation of skeletal muscle contractile function by NO, from pharmacological agents in isolated muscle preparations to dietary nitrate supplementation in humans and animals. Pharmacological manipulation in vitro suggests that NO signaling diminishes submaximal isometric force, whereas dietary manipulation in vivo suggest that NO enhances submaximal force. The bases for these different responses are unknown but could reflect dose-dependent effects. Maximal isometric force is unaffected by physiologically relevant levels of NO, which do not induce overt protein oxidation. Pharmacological and dietary manipulation of NO signaling enhances the maximal rate of isometric force development, unloaded shortening velocity, and peak power. We hypothesize that these effects are mediated by post-translational modifications of myofibrillar proteins that modulate thick filament regulation of contraction (e.g., mechanosensing and strain-dependence of cross-bridge kinetics). NO effects on contractile function appear to have some level of fiber type and sex-specificity. The mechanisms behind NO-mediated changes in skeletal muscle function need to be explored through proteomics analysis and advanced biophysical assays to advance the development of small molecules and open intriguing therapeutic and ergogenic possibilities for aging, disease, and athletic performance.
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Chetrit E, Sharma S, Maayan U, Pelah MG, Klausner Z, Popa I, Berkovich R. Nonexponential kinetics in captured in sequential unfolding of polyproteins over a range of loads. Curr Res Struct Biol 2022; 4:106-117. [PMID: 35540955 PMCID: PMC9079174 DOI: 10.1016/j.crstbi.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 11/08/2022] Open
Abstract
While performing under mechanical loads in vivo, polyproteins are vitally involved in cellular mechanisms such as regulation of tissue elasticity and mechano-transduction by unfolding their comprising domains and extending them. It is widely thought that the process of sequential unfolding of polyproteins follows an exponential kinetics as the individual unfolding events exhibit identical and identically distributed (iid) Poisson behavior. However, it was shown that under high loads, the sequential unfolding kinetics displays nonexponential kinetics that alludes to aging by a subdiffusion process. Statistical order analysis of this kinetics indicated that the individual unfolding events are not iid, and cannot be defined as a Poisson (memoryless) process. Based on numerical simulations it was argued that this behavior becomes less pronounced with lowering the load, therefore it is to be expected that polyproteins unfolding under lower forces will follow a Poisson behavior. This expectation serves as the motivation of the current study, in which we investigate the effect of force lowering on the unfolding kinetics of Poly-L8 under varying loads, specifically high (150, 100 pN) and moderate-low (45, 30, 20 pN) forces. We found that a hierarchy among the unfolding events still exists even under low loads, again resulting in nonexponential behavior. We observe that analyzing the dwell-time distributions with stretched-exponentials and power laws give rise to different phenomenological trends. Using statistical order analysis, we demonstrated that even under the lowest load, the sequential unfolding cannot be considered as iid, in accord with the power law distribution. Additional free energy analysis revealed the contribution of the unfolded segments elasticity that scales with the force on the overall one-dimensional contour of the energy landscape, but more importantly, it discloses the hierarchy within the activation barriers during sequential unfolding that account for the observed nonexponentiality. Poly-L8 unfolding shows nonexponential kinetics at forces ranging from 150 to 20 pN. Different phenomenological trends are observed for the dwell-time distributions. The unfolding events were shown to be dependent and not identically distributed. Free energy analysis reveals elastic impact and hierarchy in the unfolding barriers.
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Momb BA, Patino E, Akchurin OM, Miller MS. Iron Supplementation Improves Skeletal Muscle Contractile Properties in Mice with CKD. KIDNEY360 2022; 3:843-858. [PMID: 36128477 PMCID: PMC9438424 DOI: 10.34067/kid.0004412021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 03/18/2022] [Indexed: 01/12/2023]
Abstract
Background Patients with chronic kidney disease (CKD) frequently have compromised physical performance, which increases their mortality; however, their skeletal muscle dysfunction has not been characterized at the single-fiber and molecular levels. Notably, interventions to mitigate CKD myopathy are scarce. Methods The effect of CKD in the absence and presence of iron supplementation on the contractile function of individual skeletal muscle fibers from the soleus and extensor digitorum longus muscles was evaluated in 16-week-old mice. CKD was induced by the adenine diet, and iron supplementation was by weekly iron dextran injections. Results Maximally activated and fatigued fiber force production was decreased 24%-52% in untreated CKD, independent of size, by reducing strongly bound myosin/actin cross-bridges and/or decreasing myofilament stiffness in myosin heavy chain (MHC) I, IIA, and IIB fibers. Additionally, myosin/actin interactions in untreated CKD were slower for MHC I and IIA fibers and unchanged or faster in MHC IIB fibers. Iron supplementation improved anemia and did not change overall muscle mass in CKD mice. Iron supplementation ameliorated CKD-induced myopathy by increasing strongly bound cross-bridges, leading to improved specific tension, and/or returning the rate of myosin/actin interactions toward or equivalent to control values in MHC IIA and IIB fibers. Conclusions Skeletal muscle force production was significantly reduced in untreated CKD, independent of fiber size, indicating that compromised physical function in patients is not solely due to muscle mass loss. Iron supplementation improved multiple aspects of CKD-induced myopathy, suggesting that timely correction of iron imbalance may aid in ameliorating contractile deficits in CKD patients.
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Affiliation(s)
- Brent A. Momb
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Edwin Patino
- Joan and Sanford I. Weill Department of Medicine, Division of Nephrology and Hypertension, Weill Cornell Medicine, New York, New York
| | - Oleh M. Akchurin
- Department of Pediatrics, Division of Pediatric Nephrology, Weill Cornell Medicine, New York, New York,New York-Presbyterian Hospital, New York, New York
| | - Mark S. Miller
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
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González-Jamett A, Vásquez W, Cifuentes-Riveros G, Martínez-Pando R, Sáez JC, Cárdenas AM. Oxidative Stress, Inflammation and Connexin Hemichannels in Muscular Dystrophies. Biomedicines 2022; 10:biomedicines10020507. [PMID: 35203715 PMCID: PMC8962419 DOI: 10.3390/biomedicines10020507] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/13/2022] [Accepted: 02/15/2022] [Indexed: 12/16/2022] Open
Abstract
Muscular dystrophies (MDs) are a heterogeneous group of congenital neuromuscular disorders whose clinical signs include myalgia, skeletal muscle weakness, hypotonia, and atrophy that leads to progressive muscle disability and loss of ambulation. MDs can also affect cardiac and respiratory muscles, impairing life-expectancy. MDs in clude Duchenne muscular dystrophy, Emery-Dreifuss muscular dystrophy, facioscapulohumeral muscular dystrophy and limb-girdle muscular dystrophy. These and other MDs are caused by mutations in genes that encode proteins responsible for the structure and function of skeletal muscles, such as components of the dystrophin-glycoprotein-complex that connect the sarcomeric-actin with the extracellular matrix, allowing contractile force transmission and providing stability during muscle contraction. Consequently, in dystrophic conditions in which such proteins are affected, muscle integrity is disrupted, leading to local inflammatory responses, oxidative stress, Ca2+-dyshomeostasis and muscle degeneration. In this scenario, dysregulation of connexin hemichannels seem to be an early disruptor of the homeostasis that further plays a relevant role in these processes. The interaction between all these elements constitutes a positive feedback loop that contributes to the worsening of the diseases. Thus, we discuss here the interplay between inflammation, oxidative stress and connexin hemichannels in the progression of MDs and their potential as therapeutic targets.
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Affiliation(s)
- Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (W.V.); (J.C.S.)
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile; (G.C.-R.); (R.M.-P.)
- Correspondence: (A.G.-J.); (A.M.C.)
| | - Walter Vásquez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (W.V.); (J.C.S.)
| | - Gabriela Cifuentes-Riveros
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile; (G.C.-R.); (R.M.-P.)
| | - Rafaela Martínez-Pando
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile; (G.C.-R.); (R.M.-P.)
| | - Juan C. Sáez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (W.V.); (J.C.S.)
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (W.V.); (J.C.S.)
- Correspondence: (A.G.-J.); (A.M.C.)
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Stirnemann G. Recent Advances and Emerging Challenges in the Molecular Modeling of Mechanobiological Processes. J Phys Chem B 2022; 126:1365-1374. [PMID: 35143190 DOI: 10.1021/acs.jpcb.1c10715] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many biological processes result from the effect of mechanical forces on macromolecular structures and on their interactions. In particular, the cell shape, motion, and differentiation directly depend on mechanical stimuli from the extracellular matrix or from neighboring cells. The development of experimental techniques that can measure and characterize the tiny forces acting at the cellular scale and down to the single-molecule, biomolecular level has enabled access to unprecedented details about the involved mechanisms. However, because the experimental observables often do not provide a direct atomistic picture of the corresponding phenomena, particle-based simulations performed at various scales are instrumental in complementing these experiments and in providing a molecular interpretation. Here, we will review the recent key achievements in the field, and we will highlight and discuss the many technical challenges these simulations are facing, as well as suggest future directions for improvement.
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Affiliation(s)
- Guillaume Stirnemann
- CNRS Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique, PSL University, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France
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Frischholz J, Raiteri BJ, Cresswell AG, Hahn D. Corticospinal excitability remains unchanged in the presence of residual force enhancement and does not contribute to increased torque production. PeerJ 2022; 10:e12729. [PMID: 35036100 PMCID: PMC8743010 DOI: 10.7717/peerj.12729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 12/10/2021] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Following stretch of an active muscle, muscle force is enhanced, which is known as residual force enhancement (rFE). As earlier studies found apparent corticospinal excitability modulations in the presence of rFE, this study aimed to test whether corticospinal excitability modulations contribute to rFE. METHODS Fourteen participants performed submaximal plantar flexion stretch-hold and fixed-end contractions at 30% of their maximal voluntary soleus muscle activity in a dynamometer. During the steady state of the contractions, participants either received subthreshold or suprathreshold transcranial magnetic stimulation (TMS) of their motor cortex, while triceps surae muscle responses to stimulation were obtained via electromyography (EMG), and net ankle joint torque was recorded. B-mode ultrasound imaging was used to confirm muscle fascicle stretch during stretch-hold contractions in a subset of participants. RESULTS Following stretch of the plantar flexors, an average rFE of 7% and 11% was observed for contractions with subthreshold and suprathreshold TMS, respectively. 41-46 ms following subthreshold TMS, triceps surae muscle activity was suppressed by 19-25%, but suppression was not significantly different between stretch-hold and fixed-end contractions. Similarly, the reduction in plantar flexion torque following subthreshold TMS was not significantly different between contraction conditions. Motor evoked potentials, silent periods and superimposed twitches following suprathreshold TMS were also not significantly different between contraction conditions. DISCUSSION As TMS of the motor cortex did not result in any differences between stretch-hold and fixed-end contractions, we conclude that rFE is not linked to changes in corticospinal excitability.
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Affiliation(s)
- Jasmin Frischholz
- Human Movement Science, Faculty of Sport Science, Ruhr University Bochum, Bochum, Germany
| | - Brent J. Raiteri
- Human Movement Science, Faculty of Sport Science, Ruhr University Bochum, Bochum, Germany
| | - Andrew G. Cresswell
- School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia
| | - Daniel Hahn
- Human Movement Science, Faculty of Sport Science, Ruhr University Bochum, Bochum, Germany,School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia
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Nanosurgical Manipulation of Titin and Its M-Complex. NANOMATERIALS 2022; 12:nano12020178. [PMID: 35055197 PMCID: PMC8779236 DOI: 10.3390/nano12020178] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 01/21/2023]
Abstract
Titin is a multifunctional filamentous protein anchored in the M-band, a hexagonally organized supramolecular lattice in the middle of the muscle sarcomere. Functionally, the M-band is a framework that cross-links myosin thick filaments, organizes associated proteins, and maintains sarcomeric symmetry via its structural and putative mechanical properties. Part of the M-band appears at the C-terminal end of isolated titin molecules in the form of a globular head, named here the “M-complex”, which also serves as the point of head-to-head attachment of titin. We used high-resolution atomic force microscopy and nanosurgical manipulation to investigate the topographical and internal structure and local mechanical properties of the M-complex and its associated titin molecules. We find that the M-complex is a stable structure that corresponds to the transverse unit of the M-band organized around the myosin thick filament. M-complexes may be interlinked into an M-complex array that reflects the local structural and mechanical status of the transversal M-band lattice. Local segments of titin and the M-complex could be nanosurgically manipulated to achieve extension and domain unfolding. Long threads could be pulled out of the M-complex, suggesting that it is a compact supramolecular reservoir of extensible filaments. Nanosurgery evoked an unexpected volume increment in the M-complex, which may be related to its function as a mechanical spacer. The M-complex thus displays both elastic and plastic properties which support the idea that the M-band may be involved in mechanical functions within the muscle sarcomere.
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Riley LA, Zhang X, Douglas CM, Mijares JM, Hammers DW, Wolff CA, Wood NB, Olafson HR, Du P, Labeit S, Previs MJ, Wang ET, Esser KA. The skeletal muscle circadian clock regulates titin splicing through RBM20. eLife 2022; 11:76478. [PMID: 36047761 PMCID: PMC9473687 DOI: 10.7554/elife.76478] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 08/31/2022] [Indexed: 02/01/2023] Open
Abstract
Circadian rhythms are maintained by a cell-autonomous, transcriptional-translational feedback loop known as the molecular clock. While previous research suggests a role of the molecular clock in regulating skeletal muscle structure and function, no mechanisms have connected the molecular clock to sarcomere filaments. Utilizing inducible, skeletal muscle specific, Bmal1 knockout (iMSBmal1-/-) mice, we showed that knocking out skeletal muscle clock function alters titin isoform expression using RNAseq, liquid chromatography-mass spectrometry, and sodium dodecyl sulfate-vertical agarose gel electrophoresis. This alteration in titin's spring length resulted in sarcomere length heterogeneity. We demonstrate the direct link between altered titin splicing and sarcomere length in vitro using U7 snRNPs that truncate the region of titin altered in iMSBmal1-/- muscle. We identified a mechanism whereby the skeletal muscle clock regulates titin isoform expression through transcriptional regulation of Rbm20, a potent splicing regulator of titin. Lastly, we used an environmental model of circadian rhythm disruption and identified significant downregulation of Rbm20 expression. Our findings demonstrate the importance of the skeletal muscle circadian clock in maintaining titin isoform through regulation of RBM20 expression. Because circadian rhythm disruption is a feature of many chronic diseases, our results highlight a novel pathway that could be targeted to maintain skeletal muscle structure and function in a range of pathologies.
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Affiliation(s)
- Lance A Riley
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Xiping Zhang
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Collin M Douglas
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Joseph M Mijares
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - David W Hammers
- Myology Institute, University of FloridaGainesvilleUnited States,Department of Pharmacology and Therapeutics, University of FloridaGainesvilleUnited States
| | - Christopher A Wolff
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
| | - Neil B Wood
- Department of Molecular Physiology and Biophysics, University of VermontBurlingtonUnited States
| | - Hailey R Olafson
- Department of Molecular Genetics of Microbiology, Center for Neurogenetics, University of FloridaGainesvilleUnited States
| | - Ping Du
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States
| | - Siegfried Labeit
- Medical Faculty Mannheim, University of HeidelbergMannheimGermany
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of VermontBurlingtonUnited States
| | - Eric T Wang
- Myology Institute, University of FloridaGainesvilleUnited States,Department of Molecular Genetics of Microbiology, Center for Neurogenetics, University of FloridaGainesvilleUnited States
| | - Karyn A Esser
- Department of Physiology and Functional Genomics, University of FloridaGainesvilleUnited States,Myology Institute, University of FloridaGainesvilleUnited States
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Shi J, Watanabe D, Wada M. Effects of vigorous isometric muscle contraction on titin stiffness-related contractile properties in rat fast-twitch muscles. Am J Physiol Regul Integr Comp Physiol 2021; 321:R858-R868. [PMID: 34668430 DOI: 10.1152/ajpregu.00189.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022]
Abstract
This study was conducted to examine the effects of an acute bout of vigorous isometric contractions on titin stiffness-related contractile properties in rat fast-twitch skeletal muscles. Intact gastrocnemius muscles were electrically stimulated in situ until the force was reduced to ∼50% of the initial force. Immediately after cessation of the stimulation, the superficial regions of the muscles were dissected and subjected to biochemical and skinned fiber analyses. The stimulation resulted in a decrease in the titin-based passive force. The amounts of fragmented titin were unchanged by the stimulation. Protein kinase Cα-treatment increased the passive force in stimulated fibers to resting levels. The stimulation had no effect on the maximum Ca2+-activated force (max Ca2+ force) at a sarcomere length (SL) of 2.4 μm and decreased myofibrillar (my)-Ca2+ sensitivity at 2.6-μm SL. Stretching the SL to 3.0 μm led to the augmentation of the max Ca2+ force and my-Ca2+ sensitivity in both rested and stimulated fibers. For the max Ca2+ force, the extent of the increase was smaller in stimulated than in rested fibers, whereas for my-Ca2+ sensitivity, it was higher in stimulated than in rested fibers. These results suggest that vigorous isometric contractions decrease the titin-based passive force, possibly because of a reduction in phosphorylation by protein kinase Cα, and that the decreased titin stiffness may contribute, at least in part, to muscle fatigue.
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Affiliation(s)
- Jiayu Shi
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima-shi, Japan
| | - Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Higashihiroshima-shi, Japan
| | - Masanobu Wada
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima-shi, Japan
- Graduate School of Humanities and Social Sciences, Hiroshima University, Higashihiroshima-shi, Japan
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Spatiotemporal Regulation and Functional Analysis of Circular RNAs in Skeletal Muscle and Subcutaneous Fat during Pig Growth. BIOLOGY 2021; 10:biology10090841. [PMID: 34571718 PMCID: PMC8465536 DOI: 10.3390/biology10090841] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 11/16/2022]
Abstract
Recently, thousands of circular RNAs have been reported in different pig breeds. However, researches on the temporal and spatial expression patterns of circRNA over the period of animal growth are limited. Here, we systematically analyzed circRNAs in skeletal muscle and subcutaneous fat in four growth time points (30 days, 90 days, 150 days and 210 days after birth) of a Chinese native pig breed, Ningxiang pigs. A total of 1171 differentially expressed (DE) circRNAs between muscle and fat were identified, including 562 upregulated and 609 downregulated circRNAs. KEGG pathway enrichment analysis of these DE circRNAs revealed that host genes were mainly involved in glycogen metabolism signaling pathways, muscle development signaling pathways such as ErbB pathway and adipocytokine signaling pathways and AMPK signaling pathways and fatty acid biosynthesis. The circRNAs have striking spatiotemporal specificity in the form of dynamic expression at 90 d. Short Time-Series Expression Miner analysis showed multiple model spectra that are significantly enriched with time changes in muscle and fat. Our findings provide new ideas and perspectives about the role of circular RNAs and their targeting relations with mRNA and miRNA in skeletal muscle and fat tissue during pig growth.
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Yu M, Lu JH, Le S, Yan J. Unexpected Low Mechanical Stability of Titin I27 Domain at Physiologically Relevant Temperature. J Phys Chem Lett 2021; 12:7914-7920. [PMID: 34384021 DOI: 10.1021/acs.jpclett.1c01309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The extensively studied immunoglobulin (Ig) domain I27 of the giant force-bearing protein titin has provided a basis for our current understanding of the structural stability, dynamics, and function of the numerous mechanically stretched Ig domains in the force-bearing I-band of titin. The current consensus is that titin I27 has a high mechanical stability characterized by very low unfolding rate (<10-3 s-1) in physiological force range and high unfolding forces (>100 pN) at typical physiological force loading rates from experiments at typical laboratory temperatures. Here, we report that when the temperature is increased from 23 to 37 °C, the unfolding rate of I27 drastically increases by ∼100-fold at the physiological level of forces, indicating a low mechanical stability of I27 at physiological conditions. The result provides new insights into the structural states and the associated functions of I27 and other similar titin I-band Ig domains.
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Affiliation(s)
- Miao Yu
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Jung-Hsuan Lu
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Shimin Le
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
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Alegre-Cebollada J. Protein nanomechanics in biological context. Biophys Rev 2021; 13:435-454. [PMID: 34466164 PMCID: PMC8355295 DOI: 10.1007/s12551-021-00822-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022] Open
Abstract
How proteins respond to pulling forces, or protein nanomechanics, is a key contributor to the form and function of biological systems. Indeed, the conventional view that proteins are able to diffuse in solution does not apply to the many polypeptides that are anchored to rigid supramolecular structures. These tethered proteins typically have important mechanical roles that enable cells to generate, sense, and transduce mechanical forces. To fully comprehend the interplay between mechanical forces and biology, we must understand how protein nanomechanics emerge in living matter. This endeavor is definitely challenging and only recently has it started to appear tractable. Here, I introduce the main in vitro single-molecule biophysics methods that have been instrumental to investigate protein nanomechanics over the last 2 decades. Then, I present the contemporary view on how mechanical force shapes the free energy of tethered proteins, as well as the effect of biological factors such as post-translational modifications and mutations. To illustrate the contribution of protein nanomechanics to biological function, I review current knowledge on the mechanobiology of selected muscle and cell adhesion proteins including titin, talin, and bacterial pilins. Finally, I discuss emerging methods to modulate protein nanomechanics in living matter, for instance by inducing specific mechanical loss-of-function (mLOF). By interrogating biological systems in a causative manner, these new tools can contribute to further place protein nanomechanics in a biological context.
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Mazzo MR, Weinman LE, Giustino V, Mclagan B, Maldonado J, Enoka RM. Changes in neural drive to calf muscles during steady submaximal contractions after repeated static stretches. J Physiol 2021; 599:4321-4336. [PMID: 34292610 DOI: 10.1113/jp281875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/19/2021] [Indexed: 01/27/2023] Open
Abstract
KEY POINTS Repeated static-stretching interventions consistently increase the range of motion about a joint and decrease total joint stiffness, but findings on the changes in muscle and connective-tissue properties are mixed. The influence of these stretch-induced changes on muscle function at submaximal forces is unknown. To address this gap in knowledge, the changes in neural drive to the plantar flexor muscles after a static-stretch intervention were estimated. Neural drive to the plantar flexor muscles during a low-force contraction increased after repeated static stretches. These findings suggest that adjustments in motor unit activity are necessary at low forces to accommodate reductions in the force-generating and transmission capabilities of the muscle-tendon unit after repeated static stretches of the calf muscles. ABSTRACT Static stretching decreases stiffness about a joint, but its influence on muscle-tendon unit function and muscle activation is unclear. We investigated the influence of three static stretches on changes in neural drive to the plantar flexor muscles, both after a stretch intervention and after a set of maximal voluntary contractions (MVCs). Estimates of neural drive were obtained during submaximal isometric contractions by decomposing high-density electromyographic signals into the activity of individual motor units from medial gastrocnemius, lateral gastrocnemius and soleus. Motor units were matched across contractions and an estimate of neural drive to the plantar flexors was calculated by normalizing the cumulative spike train to the number of active motor units (normalized neural drive). Mean discharge rate increased after the stretch intervention during the 10% MVC task for all recorded motor units and those matched across conditions (all, P = 0.0046; matched only, P = 0.002), recruitment threshold decreased for motor units matched across contractions (P = 0.022), and discharge rate at recruitment was elevated (P = 0.004). Similarly, the estimate of normalized neural drive was significantly greater after the stretch intervention at 10% MVC torque (P = 0.029), but not at 35% MVC torque. The adjustments in motor unit activity required to complete the 10% MVC task after stretch may have been partially attenuated by a set of plantar flexor MVCs. The increase in neural drive required to produce low plantar-flexion torques after repeated static stretches of the calf muscles suggests stretch-induced changes in muscle and connective tissue properties.
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Affiliation(s)
- Melissa R Mazzo
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
| | - Logan E Weinman
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
| | - Valerio Giustino
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Bailey Mclagan
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
| | - John Maldonado
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
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The Sarcomeric Spring Protein Titin: Biophysical Properties, Molecular Mechanisms, and Genetic Mutations Associated with Heart Failure and Cardiomyopathy. Curr Cardiol Rep 2021; 23:121. [PMID: 34269900 DOI: 10.1007/s11886-021-01550-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/07/2021] [Indexed: 01/06/2023]
Abstract
PURPOSE OF REVIEW The giant protein titin forms the "elastic" filament of the sarcomere, essential for the mechanical compliance of the heart muscle. Titin serves a biological spring, and therefore structural modifications of titin affect function of the myocardium and are associated with heart failure and cardiomyopathy. RECENT FINDINGS In this review, we discuss the current understanding of titin's biophysical properties and how modifications contribute to cardiac function and heart failure. In addition, we review the most recent data on the clinical impact and phenotype heterogeneity of TTN truncating variants, including diseases involving striated muscles, and prospects for future therapies. Because of the giant structure of the titin protein and the complexity of its function, titin's role in health and disease is not yet completely understood. Future research efforts need to focus on novel therapeutic approaches able to modulate titin transcriptional and post-translational modification.
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Bjørnsen T, Wernbom M, Paulsen G, Markworth JF, Berntsen S, D'Souza RF, Cameron-Smith D, Raastad T. High-frequency blood flow-restricted resistance exercise results in acute and prolonged cellular stress more pronounced in type I than in type II fibers. J Appl Physiol (1985) 2021; 131:643-660. [PMID: 33955259 DOI: 10.1152/japplphysiol.00115.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Myocellular stress with high-frequency blood flow-restricted resistance exercise (BFRRE) was investigated by measures of heat shock protein (HSP) responses, glycogen content, and inflammatory markers. Thirteen participants [age: 24 ± 2 yr (means ± SD), 9 males] completed two 5-day blocks of seven BFRRE sessions, separated by 10 days. Four sets of unilateral knee extensions to failure at 20% of one-repetition maximum (1RM) were performed. Muscle samples obtained before, 1 h after the first session in the first and second block (acute 1 and acute 2), after three sessions (day 4), during the "rest week," and at 3 (post 3) and 10 days postintervention (post 10) were analyzed for HSP70, αB-crystallin, glycogen [periodic acid-Schiff (PAS) staining], mRNAs, miRNAs, and CD68+ (macrophages) and CD66b+ (neutrophils) cell numbers. αB-crystallin translocated from the cytosolic to the cytoskeletal fraction after acute 1 and acute 2 (P < 0.05) and immunostaining revealed larger responses in type I than in type II fibers (acute 1, 225 ± 184% vs. 92 ± 81%, respectively, P = 0.001). HSP70 was increased in the cytoskeletal fraction at day 4 and post 3, and immunostaining intensities were more elevated in type I than in type II fibers at day 4 (206 ± 84% vs. 72 ± 112%, respectively, P <0.001), during the rest week (98 ± 66% vs. 42 ± 79%, P < 0.001), and at post 3 (115 ± 82% vs. 28 ± 78%, P = 0.003). Glycogen content was reduced in both fiber types, but most pronounced in type I, which did not recover until the rest week (-15% to 29%, P ≤ 0.001). Intramuscular macrophage numbers were increased by ∼65% postintervention, but no changes were observed in muscle neutrophils. We conclude that high-frequency BFRRE with sets performed till failure stresses both fiber types, with type I fibers being most affected.NEW & NOTEWORTHY BFRRE has been reported to preferentially stress type I muscle fibers, as evidenced by HSP responses. We extend these findings by showing that the HSP responses occur in both fiber types but more so in type I fibers and that they can still be induced after a short-term training period. Furthermore, the reductions in glycogen content of type I fibers after strenuous frequent BFRRE in unaccustomed subjects can be prolonged (≥5 days), probably due to microdamage.
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Affiliation(s)
- Thomas Bjørnsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway.,Norwegian Olympic Federation, Oslo, Norway
| | - Mathias Wernbom
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.,The Rydberg Laboratory for Applied Sciences, Halmstad University, Halmstad, Sweden.,Department of Food and Nutrition, and Sport Science, Center for Health and Performance, University of Gothenburg, Göteborg, Sweden
| | - Gøran Paulsen
- Norwegian Olympic Federation, Oslo, Norway.,Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | | | - Sveinung Berntsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway
| | - Randall F D'Souza
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Discipline of Nutrition, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - David Cameron-Smith
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Singapore Institute for Clinical Sciences, Agency for Science, Technology, and Research, Singapore.,Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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