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Journal of Muscle Research and Cell Motility

Esther Barreiro, Shahragim Tajbakhsh
In eukaryote cells, chromatin appears in several forms and is composed of genomic DNA, protein and RNA. The protein content of chromatin is composed primarily of core histones that are packaged into nucleosomes resulting in the condensation of the DNA. Several epigenetic mechanisms regulate the stability of the nucleosomes and the protein-protein interactions that modify the transcriptional activity of the DNA. Interestingly, epigenetic control of gene expression has recently emerged as a relevant mechanism involved in the regulation of many different biological processes including that of muscle development, muscle mass maintenance, function, and phenotype in health and disease...
March 28, 2017: Journal of Muscle Research and Cell Motility
C J Barclay
The energy required for muscle contraction is provided by the breakdown of ATP but the amount of ATP in muscles cells is sufficient to power only a short duration of contraction. Buffering of ATP by phosphocreatine, a reaction catalysed by creatine kinase, extends the duration of activity possible but sustained activity depends on continual regeneration of PCr. This is achieved using ATP generated by oxidative processes and, during intense activity, by anaerobic glycolysis. The rate of ATP breakdown ranges from 70 to 140 mM min(-1) during isometric contractions of various intensity to as much as 400 mM min(-1) during intense, dynamic activity...
March 12, 2017: Journal of Muscle Research and Cell Motility
Yusuke Komiya, Shoko Sawano, Daisuke Mashima, Riho Ichitsubo, Mako Nakamura, Ryuichi Tatsumi, Yoshihide Ikeuchi, Wataru Mizunoya
Skeletal muscle is the main tissue of lipid metabolism and accordingly is critical for homeostasis and energy production; however, the determinants of lipid accumulation in skeletal muscle are unknown. Here, we examined whether the soleus muscle (predominantly slow-twitch fibers) has a higher lipid accumulation capacity than that of the extensor digitorum longus (EDL, predominantly fast-twitch fibers) muscle in mice. Soleus and EDL muscles were harvested from male C57BL/6J mice. The mRNA levels of genes involved in fatty acid import and triglyceride synthesis and accumulation were examined in soleus and EDL muscles...
March 9, 2017: Journal of Muscle Research and Cell Motility
Stefan Matecki, Boris Jung, Nathalie Saint, Valerie Scheuermann, Samir Jaber, Alain Lacampagne
Respiratory muscle contractile inactivity during mechanical ventilation (MV) induces diaphragm muscle weakness, a condition referred to as ventilator-induced diaphragmatic dysfunction (VIDD). Although VIDD pathophysiological mechanisms are still not fully understood, it has been recently suggested that remodeling of the sarcoplasmic reticulum (SR) calcium release channel/ryanodine receptors (RyR1) in the diaphragm is a proximal mechanism of VIDD. Here, we used piglets, a large animal model of VIDD that is more relevant to human pathophysiology, to determine whether RyR1 alterations are observed in the presence of diaphragm weakness...
March 4, 2017: Journal of Muscle Research and Cell Motility
William Gittings, Jordan Bunda, Rene Vandenboom
We investigated the influence of shortening speed on concentric force potentiation at different frequencies in muscles devoid of skeletal myosin light chain kinase (skMLCK(-/-)) and unable to phosphorylate myosin. EDL muscles from skMLCK(-/-) mice were activated in vitro (25 °C) across a range of stimulation frequencies (10-100 Hz) during shortening ramps at 0.10, 0.30, or 0.50 of maximum shortening velocity (Vmax) before and after a potentiating stimulus (PS). When collapsed across all frequencies, the PS increased relative (post/pre) concentric force to 1...
March 2, 2017: Journal of Muscle Research and Cell Motility
Mélanie Gueffier, Justin Zintz, Karen Lambert, Amanda Finan, Franck Aimond, Nourdine Chakouri, Christophe Hédon, Mathieu Granier, Pierre Launay, Jérôme Thireau, Sylvain Richard, Marie Demion
Cardiac hypertrophy (CH) is an adaptive process that exists in two distinct forms and allows the heart to adequately respond to an organism's needs. The first form of CH is physiological, adaptive and reversible. The second is pathological, irreversible and associated with fibrosis and cardiomyocyte death. CH involves multiple molecular mechanisms that are still not completely defined but it is now accepted that physiological CH is associated more with the PI3-K/Akt pathway while the main signaling cascade activated in pathological CH involves the Calcineurin-NFAT pathway...
February 21, 2017: Journal of Muscle Research and Cell Motility
(no author information available yet)
No abstract text is available yet for this article.
February 8, 2017: Journal of Muscle Research and Cell Motility
Giorgia Valle, Barbara Vergani, Roberta Sacchetto, Carlo Reggiani, Edith De Rosa, Lisa Maccatrozzo, Alessandra Nori, Antonello Villa, Pompeo Volpe
This study investigates the functional role of calsequestrin 2 (CASQ2) in both fast-twitch and slow-twitch skeletal muscles by using CASQ2-/- mice; CASQ2 is expressed throughout life in slow-twitch muscles, but only in the developmental and neonatal stages in fast-twitch muscles. CASQ2-/- causes increase in calsequestrin 1 (CASQ1) expression, but without functional changes in both muscle types. CASQ2-/- mice have ultrastructural changes in fast-twitch muscles only, i.e., formation of pentads and stacks in the sarcoplasmic reticulum...
January 27, 2017: Journal of Muscle Research and Cell Motility
Michelle L Munro, Christian Soeller
The ventricular cardiomyocytes of adult mammals contain invaginations of the plasma membrane known as transverse (t)-tubules. These regular structures are essential for the synchronisation of excitation-contraction (EC) coupling throughout the cell, which is a vital process for cardiac function. T-tubules form a close association with the sarcoplasmic reticulum (SR) to form junctions, where several key proteins involved in EC coupling are localised, including the SR calcium release channels-the ryanodine receptors (RyR)...
January 6, 2017: Journal of Muscle Research and Cell Motility
Sherif M Reda, Sampath K Gollapudi, Murali Chandra
The N-terminal extension of human cardiac troponin T (TnT), which modulates myofilament Ca(2+) sensitivity, contains several hypertrophic cardiomyopathy (HCM)-causing mutations including S69F. However, the functional consequence of S69F mutation is unknown. The human analog of S69F in rat TnT is L71F (TnTL71F). Because the functional consequences due to structural changes in the N-terminal extension are influenced by the type of myosin heavy chain (MHC) isoform, we hypothesized that the TnTL71F-mediated effect would be differently modulated by α- and β-MHC isoforms...
December 14, 2016: Journal of Muscle Research and Cell Motility
Masataka Kawai, Tarek S Karam, John Jeshurun Michael, Li Wang, Murali Chandra
In mammalian ventricles, two myosin heavy chain (MHC) isoforms have been identified. Small animals express α-MHC, whereas large animals express β-MHC, which contribute to a large difference in the heart rate. Sprague-Dawley rats possessing ~99% α-MHC were treated with propylthiouracil to result in 100% β-MHC. Papillary muscles were skinned, dissected into small fibers, and used for experiments. To understand the functional difference between α-MHC and β-MHC, skinned-fibers were activated under the intracellular ionic conditions: 5 mM MgATP, 1 mM Mg(2+), 8 mM Pi, 200 mM ionic strength, pH 7...
December 10, 2016: Journal of Muscle Research and Cell Motility
Alf Månsson
Bridging the gaps between experimental systems on different hierarchical scales is needed to overcome remaining challenges in the understanding of muscle contraction. Here, a mathematical model with well-characterized structural and biochemical actomyosin states is developed to that end. We hypothesize that this model accounts for generation of force and motion from single motor molecules to the large ensembles of muscle. In partial support of this idea, a wide range of contractile phenomena are reproduced without the need to invoke cooperative interactions or ad hoc states/transitions...
December 2016: Journal of Muscle Research and Cell Motility
Jérôme Roy, Jean-Yves Le Guennec
Since 40 years, it is known that omega-3 poly-unsaturated fatty acids (ω3 PUFAs) have cardioprotective effects. These include antiarrhythmic effects, improvements of autonomic function, endothelial function, platelet anti-aggregation and inflammatory properties, lowering blood pressure, plaque stabilization and reduced atherosclerosis. However, recently, conflicting results regarding the health benefits of ω3 PUFAs from seafood or ω3 PUFAs supplements have emerged. The aim of this review is to examine recent literature regarding health aspects of ω3 PUFAs intake from fish or supplements, and to discuss different arguments/reasons supporting these conflicting findings...
November 18, 2016: Journal of Muscle Research and Cell Motility
Johann Caspar Rüegg
Wilhelm Hasselbach (1921-2015) is best known for his major contribution to the discovery and molecular elucidation of an ATP-driven active ion transport across a biological membrane. He had discovered SERCA, the calcium pump of the sarcoplasmic reticulum (Hasselbach and Makinose in Biochem Z 333:518-528, 1961; Biochem Z 339:94-111, 1963).
October 2016: Journal of Muscle Research and Cell Motility
Caputo Carlo, Bolaños Pura, Ramos Magaly, DiFranco Marino
Muscle fibres, isolated from frog tibialis anterior and mouse flexor digitorum brevis (FDB) were loaded with the fast dye MagFluo-4 to study the effects of potentiators caffeine, nitrate, Zn(2+) and perchlorate on Ca(2+) transients elicited by single action potentials. Overall, the potentiators doubled the transients amplitude and prolonged by about 1.5-fold their decay time. In contrast, as shown here for the first time, nitrate and Zn(2+), but not caffeine, activated a late, secondary component of the transient rising phase of frog but not mouse, fibres...
September 2, 2016: Journal of Muscle Research and Cell Motility
Pasquale Bianco, Massimo Reconditi, Gabriella Piazzesi, Vincenzo Lombardi
No abstract text is available yet for this article.
August 29, 2016: Journal of Muscle Research and Cell Motility
Teppei Ikeda, Osamu Ichii, Saori Otsuka-Kanazawa, Teppei Nakamura, Yaser Hosny Ali Elewa, Yasuhiro Kon
Skeletal muscle myofibers constantly undergo degeneration and regeneration. Histopathological features of 6 skeletal muscles (cranial tibial [CT], gastrocnemius, quadriceps femoris, triceps brachii [TB], lumbar longissimus muscles, and costal part of the diaphragm [CPD]) were compared using C57BL/10ScSn-Dmd (mdx) (mdx) mice, a model for muscular dystrophy versus control, C57BL/10 mice. Body weight and skeletal muscle mass were lower in mdx mice than the control at 4 weeks of age; these results were similar at 6-30 weeks...
July 29, 2016: Journal of Muscle Research and Cell Motility
Wenjun Zheng, Sarah E Hitchcock-DeGregori, Bipasha Barua
Tropomyosin (Tpm) is a two-chained α-helical coiled-coil protein that binds to filamentous actin (F-actin), and regulates its interactions with myosin by occupying three average positions on F-actin (blocked, closed, and open). Mutations in the Tpm are linked to heart diseases including hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). To elucidate the molecular mechanisms of Tpm mutations (including DCM mutation E54K, HCM mutations E62Q, A63V, K70T, V95A, D175N, E180G, L185R, E192K, and a designed synthetic mutation D137L) in terms of their effects on Tpm flexibility and its interactions with F-actin, we conducted extensive molecular dynamics simulations for the wild-type and mutant Tpm in complex with F-actin (total simulation time 160 ns per mutant)...
July 4, 2016: Journal of Muscle Research and Cell Motility
J Fernando Olivera, Gonzalo Pizarro
Raising the intracellular [Ca(2+)] ([Ca(2+)]i) was previously found to produce uncoupling between the electrical depolarization of the transverse tubules and contraction in skinned muscle fibers. Here we study the effect of elevated [Ca(2+)]i in voltage clamped cut fibers of frog skeletal muscle to establish how the charge movement, a measure of the activation of the dihydropyridine receptors (DHPR)-voltage sensors, and Ca(2+) release, a consequence of the opening of the ryanodine receptor (RyR)-release channels, were affected...
June 25, 2016: Journal of Muscle Research and Cell Motility
Feng Pan, Jing-Yi Mi, Yan Zhang, Xiao-Yun Pan, Yong-Jun Rui
The failure to accept reinnervation is considered to be one of the reasons for the poor motor functional recovery of intrinsic hand muscles (IHMs) after nerve injury. Rat could be a suitable model to be used in simulating motor function recovery of the IHMs after nerve injury as to the similarities in function and anatomy of the muscles between human and rat. However, few studies have reported the muscle fiber types composition and endplate morphologic characteristics of intrinsic forepaw muscles (IFMs) in the rat...
June 2016: Journal of Muscle Research and Cell Motility
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