1
|
Seow KN, Seow CY. Molecular Events of the Crossbridge Cycle Reflected in the Force–Velocity Relationship of Activated Muscle. Front Physiol 2022; 13:846284. [PMID: 35360243 PMCID: PMC8960716 DOI: 10.3389/fphys.2022.846284] [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: 12/31/2021] [Accepted: 02/15/2022] [Indexed: 11/13/2022] Open
Abstract
Muscles convert chemical energy to mechanical work. Mechanical performance of a muscle is often assessed by the muscle’s ability to shorten and generate power over a range of loads or forces, characterized by the force–velocity and force–power relationships. The hyperbolic force–velocity relationship of muscle, for a long time, has been regarded as a pure empirical description of the force–velocity data. Connections between mechanical manifestation in terms of force–velocity properties and the kinetics of the crossbridge cycle have only been established recently. In this review, we describe how the model of Huxley’s crossbridge kinetics can be transformed to the hyperbolic Hill equation, and link the changes in force–velocity properties to molecular events within the crossbridge cycle driven by ATP hydrolysis. This allows us to reinterpret some findings from previous studies on experimental interventions that altered the force–velocity relationship and gain further insight into the molecular mechanisms of muscle contraction under physiological and pathophysiological conditions.
Collapse
Affiliation(s)
- Kathryn N. Seow
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Chun Y. Seow
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Heart Lung Innovation, Providence Health Care/St. Paul’s Hospital, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Chun Y. Seow,
| |
Collapse
|
2
|
Miyashiro D, Ohtsuki M, Shimamoto Y, Wakayama J, Kunioka Y, Kobayashi T, Ishiwata S, Yamada T. Radial stiffness characteristics of the overlap regions of sarcomeres in isolated skeletal myofibrils in pre-force generating state. Biophys Physicobiol 2017; 14:207-220. [PMID: 29362706 PMCID: PMC5773156 DOI: 10.2142/biophysico.14.0_207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/14/2017] [Indexed: 12/01/2022] Open
Abstract
We have studied the stiffness of myofilament lattice in sarcomeres in the pre-force generating state, which was realized by a relaxing reagent, BDM (butane dione monoxime). First, the radial stiffness for the overlap regions of sarcomeres of isolated single myofibrils was estimated from the resulting decreases in diameter by osmotic pressure applied with the addition of Dextran. Then, the radial stiffness was also estimated from force-distance curve measurements with AFM technology. The radial stiffness for the overlap regions thus obtained was composed of a soft and a rigid component. The soft component visco-elastically changed in a characteristic fashion depending on the physiological conditions of myofibrils, suggesting that it comes from cross-bridge structures. BDM treatments significantly affected the soft radial component of contracting myofibrils depending on the approach velocity of cantilever: It was nearly equal to that in the contracting state at high approach velocity, whereas as low as that in the relaxing state at low approach velocity. However, comparable BDM treatments greatly suppressed the force production and the axial stiffness in contracting glycerinated muscle fibers and also the sliding velocity of actin filaments in the in vitro motility assay. Considering that BDM shifts the cross-bridge population from force generating to pre-force generating states in contracting muscle, the obtained results strongly suggest that cross-bridges in the pre-force generating state are visco-elastically attached to the thin filaments in such a binding manner that the axial stiffness is low but the radial stiffness significantly high similar to that in force generating state.
Collapse
Affiliation(s)
- Daisuke Miyashiro
- Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Misato Ohtsuki
- Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Yuta Shimamoto
- Department of Physics, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Jun'ichi Wakayama
- Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Yuki Kunioka
- Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Takakazu Kobayashi
- Department of Electronic Engineering, Shibaura Institute of Technology, Koto-ku, Tokyo 135-8548, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Takenori Yamada
- Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| |
Collapse
|
3
|
Seow CY. Hill's equation of muscle performance and its hidden insight on molecular mechanisms. J Gen Physiol 2013; 142:561-73. [PMID: 24277600 PMCID: PMC3840917 DOI: 10.1085/jgp.201311107] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/04/2013] [Indexed: 11/20/2022] Open
Abstract
Muscles shorten faster against light loads than they do against heavy loads. The hyperbolic equation first used by A.V. Hill over seven decades ago to illustrate the relationship between shortening velocity and load is still the predominant method used to characterize muscle performance, even though it has been regarded as purely empirical and lacking precision in predicting velocities at high and low loads. Popularity of the Hill equation has been sustained perhaps because of historical reasons, but its simplicity is certainly attractive. The descriptive nature of the equation does not diminish its role as a useful tool in our quest to understand animal locomotion and optimal design of muscle-powered devices like bicycles. In this Review, an analysis is presented to illustrate the connection between the historic Hill equation and the kinetics of myosin cross-bridge cycle based on the latest findings on myosin motor interaction with actin filaments within the structural confines of a sarcomere. In light of the new data and perspective, some previous studies of force-velocity relations of muscle are revisited to further our understanding of muscle mechanics and the underlying biochemical events, specifically how extracellular and intracellular environment, protein isoform expression, and posttranslational modification of contractile and regulatory proteins change the interaction between myosin and actin that in turn alter muscle force, shortening velocity, and the relationship between them.
Collapse
Affiliation(s)
- Chun Y Seow
- Department of Pathology and Laboratory Medicine, James Hogg Research Centre/St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia V6Z 1Y6, Canada
| |
Collapse
|
4
|
Miyashiro D, Wakayama J, Akiyama N, Kunioka Y, Yamada T. Radial stability of the actomyosin filament lattice in isolated skeletal myofibrils studied using atomic force microscopy. J Physiol Sci 2013; 63:299-310. [PMID: 23690090 PMCID: PMC10717890 DOI: 10.1007/s12576-013-0268-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/30/2013] [Indexed: 12/01/2022]
Abstract
The radial stability of the actomyosin filament lattice in skeletal myofibrils was examined by using atomic force microscopy. The diameter and the radial stiffness of the A-band region were examined based on force-distance curves obtained for single myofibrils adsorbed onto cover slips and compressed with the tip of a cantilever and with the Dextran treatment. The results obtained indicated that the A-band is composed of a couple of stiffness components having a rigid core-like component. It was further clarified that these radial components changed the thickness as well as the stiffness depending on the physiological condition of myofibrils. Notably, by decreasing the ionic strength, the diameter of the A-band region became greatly shrunken, but the rigid core-like component thickened, indicating that the electrostatic force distinctly affects the radial structure of actomyosin filament components. The results obtained were analyzed based on the elementary structures of the filament lattice composed of cross-bridges, thin filaments and thick filament backbones. It was clarified that the actomyosin filament lattice is radially deformable greatly and that (1), under mild compression, the filament lattice is stabilized primarily by the interactions of myosin heads with thin filaments and thick filament backbones, and (2), under severe compression, the electrostatic repulsive interactions between thin filaments and thick filament backbones became predominant.
Collapse
Affiliation(s)
- Daisuke Miyashiro
- Department of Physics (Biophysics Section), Tokyo University of Science, Tokyo, Japan
| | - Jun’ichi Wakayama
- Nanobiotechnology Laboratory (Food Engineering Division), National Food Research Institute, National Agriculture and Food Research Organization, Ibaraki, Japan
| | - Nao Akiyama
- Department of Physics (Biophysics Section), Tokyo University of Science, Tokyo, Japan
| | - Yuki Kunioka
- Japan Science and Technology Agency, Innovation Plaza Ishikawa, Ishikawa, Japan
| | - Takenori Yamada
- Department of Physics (Biophysics Section), Tokyo University of Science, Tokyo, Japan
| |
Collapse
|
5
|
Insights into the kinetics of Ca2+-regulated contraction and relaxation from myofibril studies. Pflugers Arch 2009; 458:337-57. [PMID: 19165498 DOI: 10.1007/s00424-008-0630-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 12/24/2008] [Indexed: 01/06/2023]
Abstract
Muscle contraction results from force-generating interactions between myosin cross-bridges on the thick filament and actin on the thin filament. The force-generating interactions are regulated by Ca(2+) via specialised proteins of the thin filament. It is controversial how the contractile and regulatory systems dynamically interact to determine the time course of muscle contraction and relaxation. Whereas kinetics of Ca(2+)-induced thin-filament regulation is often investigated with isolated proteins, force kinetics is usually studied in muscle fibres. The gap between studies on isolated proteins and structured fibres is now bridged by recent techniques that analyse the chemical and mechanical kinetics of small components of a muscle fibre, subcellular myofibrils isolated from skeletal and cardiac muscle. Formed of serially arranged repeating units called sarcomeres, myofibrils have a complete fully structured ensemble of contractile and Ca(2+) regulatory proteins. The small diameter of myofibrils (few micrometres) facilitates analysis of the kinetics of sarcomere contraction and relaxation induced by rapid changes of [ATP] or [Ca(2+)]. Among the processes studied on myofibrils are: (1) the Ca(2+)-regulated switch on/off of the troponin complex, (2) the chemical steps in the cross-bridge adenosine triphosphatase cycle, (3) the mechanics of force generation and (4) the length dynamics of individual sarcomeres. These studies give new insights into the kinetics of thin-filament regulation and of cross-bridge turnover, how cross-bridges transform chemical energy into mechanical work, and suggest that the cross-bridge ensembles of each half-sarcomere cooperate with each other across the half-sarcomere borders. Additionally, we now have a better understanding of muscle relaxation and its impairment in certain muscle diseases.
Collapse
|
6
|
Li B, Lin M, Tang Y, Wang B, Wang JHC. A novel functional assessment of the differentiation of micropatterned muscle cells. J Biomech 2008; 41:3349-53. [PMID: 19007933 DOI: 10.1016/j.jbiomech.2008.09.025] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Revised: 09/25/2008] [Accepted: 09/26/2008] [Indexed: 11/20/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a lethal disease characterized by rapid, progressive atrophy of muscle tissues. Timely screening of therapeutic interventions is necessary for the development of effective treatment approaches for DMD. We have developed an in vitro model using a combination of micropatterning of C2C12 skeletal muscle cells and cell traction force microscopy (CTFM). In this model, C2C12 cells were micropatterned on a highly elongated adhesive island such that the cells assumed a shape typical of a myotube. During differentiation, these cells gradually fused together and began expressing dystrophin, a structural protein of myotubes, meanwhile, their contractile forces, represented by cell traction forces, continually increased until the myotubes reached maturation. In addition, the high-degree alignment of cells favored myotube differentiation and dystrophin expression. Since the fundamental structural unit of muscle tissue is myofiber, which is responsible for muscle contraction, such a technology that can directly quantify the contractile forces of the myotube, a precursor of myofiber, may constitute a fast and efficient screening approach for DMD therapies.
Collapse
Affiliation(s)
- Bin Li
- MechanoBiology Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, 210 Lothrop Street, BST, E1640, Pittsburgh, PA 15213, USA
| | | | | | | | | |
Collapse
|
7
|
Li K, Zheng S, Xiao X, Wang Q, Zhou Y, Chen L. The structural characteristics and expression of neuropeptides in the esophagus of patients with congenital esophageal atresia and tracheoesophageal fistula. J Pediatr Surg 2007; 42:1433-8. [PMID: 17706510 DOI: 10.1016/j.jpedsurg.2007.03.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE The aim of this study was to investigate the structural characteristics and the expression of a group of neuropeptides in the esophagus of patients with congenital esophageal atresia and tracheoesophageal fistula (EA-TEF), as well to elucidate the roles of these neuropeptides in the pathogenesis of postoperative incoordination of esophagus after successful surgical repair of EA-TEF. METHODS Twenty-four specimens from distal tracheoesophageal fistulas of patients with EA-TEF (EA-TEF group) and 10 esophageal specimens from neonates who died of nonesophageal diseases (control group) were studied. All of the specimens were subjected to routine pathologic study, ultrastructural observation, and immunohistochemical staining for neuron-specific enolase, substance P, vasoactive intestinal polypeptide, and nitric oxide synthase. RESULTS In the EA-TEF group, mitochondria were distributed along the membrane of smooth muscle cell, whereas mitochondria in the control group were distributed along the karyotheca of the smooth muscle cells. The ratio of granulated vesicles to clear vesicles in the varicosity of the intramuscular motor nerve ending of the EA-TEF group (0.520 +/- 0.137) was much higher than that in the control group (0.192 +/- 0.020, P < .05). The percentages of specimens shown to have positive expression of neuron-specific enolase and substance P in the EA-TEF group (20.8% and 12.5%, respectively) were significantly lower than those in the control group (90% and 80% respectively, P < .05). The percentages of specimens shown to have positive expression of vasoactive intestinal polypeptide and nitric oxide synthase in the EA-TEF group (83.3% and 75%, respectively) were significantly higher than that in the control group (30% and 10% respectively, P < .05). CONCLUSION Imbalance of neurotransmitters excretion in nerve vesicle, abnormal intrinsic dysplasia of nerve plexus and increased expression of certain neuropeptides were the main characteristics of esophagus with abnormal intrinsic innervation, which may be responsible for the postoperative esophageal dysfunction of EA-TEF.
Collapse
Affiliation(s)
- Kai Li
- Department of Surgery, Children's Hospital, Medical Center of Fudan University (Former Shanghai Medical University), Shanghai 200032, PR China
| | | | | | | | | | | |
Collapse
|
8
|
Wakayama J, Shohara M, Yagi C, Ono H, Miyake N, Kunioka Y, Yamada T. Zigzag motions of the myosin-coated beads actively sliding along actin filaments suspended between immobilized beads. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1573:93-9. [PMID: 12383947 DOI: 10.1016/s0304-4165(02)00336-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The motions of myosin filaments actively sliding along suspended actin filaments were studied. By manipulating a double-beam laser tweezers, single actin filaments were suspended between immobilized microbeads. When another beads coated with myosin filaments were dragged to suspended actin filaments, the beads instantly and unidirectionally slid along the actin filaments. The video image analysis showed that the beads slid at a velocity of ca. 3-5 microm/s accompanied with zigzag motions. When beads were densely coated with myosin filaments, the sliding motions became straight and smooth. The obtained results indicate that (1) during the sliding motions, the interaction between myosin heads and actin filaments is weak and susceptible to random thermal agitations, (2) the effects of thermal agitations to the sliding motions of myofilaments are readily suppressed by mechanical constraints imposed to the filaments, and (3) the active sliding force is produced almost in parallel to the filaments axis.
Collapse
Affiliation(s)
- Jun'ichi Wakayama
- Biophysics Section, Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Japan
| | | | | | | | | | | | | |
Collapse
|