Sex-dependent responses to moderate/low-intensity swimming and loaded ladder-climbing resistance exercise in mdx mice - Journal of Muscle Research and Cell Motility

Duchenne muscular dystrophy (DMD) is a severe genetic disorder characterized by progressive muscle degeneration, and the mdx mouse has been widely used to investigate disease mechanisms and therapeutic strategies, including the impact of different exercise modalities and sex-related responses on dystrophic muscle. This study compared moderate/low-intensity swimming and loaded ladder-climbing in male and female mdx, including sedentary control groups for each sex. Animals were subjected to a 4-week swimming (30 min/day, 4 days/week) or a 15-day ladder-climbing resistance protocol (6 sessions, 3 sets of 10 climbs, every 48 h), starting at 30 and 45 days of age, respectively. All groups (male and female sedentary controls, swimming, and resistance-trained mice) were evaluated at 60 days of age. In male mdx mice, swimming reduced serum creatine kinase levels and improved limb functional performance compared to sedentary controls. In contrast, resistance exercise increased diaphragmatic fibrosis and reduced centrally nucleated fibers in biceps brachii in male mdx mice. Resistance-trained males also exhibited lower holding impulse compared to swimming-trained males. Females exhibited a milder response, with superior fatigue resistance, greater mechanical work during climbing, and superior final holding impulse compared to males. These findings demonstrate that exercise outcomes in mdx mice depend strongly on modality, intensity, and sex. Swimming provided functional benefits, while ladder-climbing induced measurable but controlled muscle adaptations, without consistent evidence of widespread damage.

doi.org

The pseudokinase domain PK1 of UNC-89/obscurin is required for mitochondrial morphology and function in C. elegans - Journal of Muscle Research and Cell Motility

UNC-89 is a giant modular protein located at the sarcomeric M-line of C. elegans striated muscle and is required for sarcomere organization and function. UNC-89 contains two protein kinase domains, PK...

link.springer.com

doi.org

Smooth muscle contractile cytoskeleton in health and disease - Journal of Muscle Research and Cell Motility

Smooth muscle cells are widespread in the human body, found in a range of tissues from the vasculature to the gut, airways, bladder and so on. They can be found as isolated cells or organised into syncytia (groups of cells). The organisation of the contractile cytoskeleton (smooth muscle actin and myosin filaments) is less well understood than that of striated (cardiac and skeletal) muscle. This review aims to explore what is known, the potential effects of mutations in smooth muscle actin, myosin and tropomyosin and how they lead to disease, and to highlight what we have still to learn about the smooth muscle contractile cytoskeleton.

doi.org

The role of melatonin in attenuation of vascular endothelin-1 reactivity via calcium channels and endothelial derived relaxing factors in STZ-induced diabetic aortic rats - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility - Diabetes mellitus can apply its first adverse effects by developing endothelial dysfunction, which can progress to diabetic vasculopathy. This study...

doi.org

Effects of culture media glucose concentration on LHCN-M2 skeletal muscle cell viability, differentiation and metabolic phenotype: a proof-of-concept study - Journal of Muscle Research and Cell Motility

In vitro skeletal muscle culture models provide important insight into the cellular mechanisms which underpin skeletal muscle physiology and metabolism in health and disease. The establishment of a model that can be cultured in physiological concentrations of glucose is an important factor in its translatability to more complex models and systems. Using the human skeletal muscle cell line, LHCN-M2 myoblasts, we aimed to determine the effects of different concentrations of glucose in culture media on cell viability, proliferation, ATP production and differentiation. LHCN-M2 myoblasts were cultured in NORM (1 g· L− 1) or HIGH (3.8 g· L− 1) glucose growth media, and cell viability, ATP production, and proliferation were measured. Immunofluorescence microscopy was used to determine LHCN-M2 differentiation into multinucleated myotubes with increasing concentrations of human serum (0.5%, 1% and 2% v/v). There were no differences in the viability, proliferation or basal ATP production rates of LHCN-M2 cells grown in NORM compared to HIGH glucose (P > 0.05). Morphological analysis revealed that myotube area was greater when differentiated in 2% compared to 0.5% human serum (P = 0.02), but myotube number and fusion index were unaffected (P > 0.05). These findings demonstrate that LHCN-M2 cells are capable of proliferating and differentiating into multinucleated myotubes under normal glucose concentrations in the culture media. Further work is required to determine the implications of media glucose concentration on the wider metabolic function and phenotype of LHCN-M2 myoblasts cells and myotubes.

doi.org

Amiodarone disrupts thyroid hormone homeostasis and impairs myogenic progression and locomotor function in zebrafish embryos - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility - Thyroid hormones (THs) are critical regulators of vertebrate embryonic development, governing cell proliferation, lineage commitment, and tissue...

doi.org

High-intensity interval training alleviates COPD-induced gastrocnemius muscle dysfunction via the BRD4/PGC-1α axis through restoring mitochondrial function and oxidative fiber composition - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility - Skeletal muscle dysfunction (SMD) associated with Chronic obstructive pulmonary disease (COPD), characterized by muscle atrophy and altered fiber type...

doi.org

Resistance-based exercise restores muscle health in dialysis patients - Journal of Muscle Research and Cell Motility

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are serious health concerns worldwide that require regular dialysis before a kidney transplant for a better quality of life. Due to aging and frailty, dialysis patients are often limited in physical activity, which can lead to multiple health complications and sometimes result in patient death. Therefore, maintaining muscle health is crucial for individuals undergoing dialysis. We recently reported that personalized resistance-based exercise can improve frailty in dialysis patients; however, the molecular mechanisms underlying its effects on muscle health remain unknown. RNA-Seq analysis revealed that exercise upregulates genes associated with muscle stemness, regeneration, and differentiation. Furthermore, our study demonstrated that exercise upregulates mitochondrial proteins involved in the oxidation of organic compounds and mitochondrial function in muscle. Moreover, we observed that exercise increased energy production via glucose uptake, glycogenesis, and fatty acid metabolism. These results suggest that personalized resistance-based muscle therapy in dialysis patients restores the expression of genes and proteins associated with muscle stemness, regeneration, differentiation, and energy generation.

doi.org

Stair-climbing resistance exercise, with or without oral turmeric (Curcuma longa L.) supplementation, relieves symptoms and promotes musculoskeletal repair in experimental rheumatoid arthritis in rats - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility - Rheumatoid arthritis is a chronic systemic inflammatory disease associated with joint inflammation, skeletal muscle dysfunction, and reduced physical...

doi.org

The effect of nimesulide on skeletal muscle hypertrophy and load progression after 8 weeks of resistance training in wistar rats - Journal of Muscle Research and Cell Motility

Resistance training is currently a widely targeted practice due to its ability to induce vital adaptations resulting from increased muscle strength (MS) and hypertrophy. There are reports of the concomitant use of nonsteroidal anti-inflammatory drugs with this practice for pain relief, which arises from the adaptive signaling of training. Based on this, the present study aimed to investigate whether the use of nimesulide concomitant with training could interfere with MS and hypertrophy. The sample consisted of 18 male Wistar rats, aged 91 days, with a body mass of 331 ± 20 g, divided into three groups: Control (CTRL, n = 4); Trained (TR, n = 7); and Trained and Treated with nimesulide (COMB, n = 7). The training protocol followed the ladder-climbing model. Nimesulide was administered orally at a dose of 2.5 mg/kg every day after training. Tissue collection of the Flexor Hallucis Longus (FHL) muscle was performed two days after the last training session. After eight weeks of the training protocol, a significant increase in MS was observed in TR and COMB compared to CTRL (p < 0.05). A significant increase in FHL muscle volume was observed in COMB compared to CTRL and TR only when muscle mass was normalized to body mass (p < 0.05), whereas no significant differences were detected among groups for absolute FHL mass. Additionally, there were no differences in training load or volume between COMB and TR (p ≥ 0.05). Therefore, based on the results, it is concluded that the administration of nimesulide during eight weeks of training promoted a greater hypertrophic response of the FHL muscle in rats.

doi.org

Smooth muscle contractile cytoskeleton in health and disease - Journal of Muscle Research and Cell Motility

Smooth muscle cells are widespread in the human body, found in a range of tissues from the vasculature to the gut, airways, bladder and so on. They can be found as isolated cells or organised into syncytia (groups of cells). The organisation of the contractile cytoskeleton (smooth muscle actin and myosin filaments) is less well understood than that of striated (cardiac and skeletal) muscle. This review aims to explore what is known, the potential effects of mutations in smooth muscle actin, myosin and tropomyosin and how they lead to disease, and to highlight what we have still to learn about the smooth muscle contractile cytoskeleton.

doi.org

Methodological framing in muscle morphology and mechanics: aligning experimental protocols with scientific questions - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility -

doi.org

Short-duration electrical pulse stimulation induces myokines and mitochondrial adaptations in C2C12 myotubes - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility - Physical activity induces rapid myokine and metabolic responses in skeletal muscle, yet the immediate cellular adaptations to short-duration...

doi.org

Assessing muscle morphology and mechanics: one protocol does not fit all - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility -

doi.org

CD36 regulates myogenic differentiation via chronic integrated stress response – implications for muscle aging - Journal of Muscle Research and Cell Motility

The integrated stress response (ISR) and mitochondrial unfolded protein response (UPRmt) plays a vital role in myogenic differentiation of muscle satellite cells. In this study, chronic ISR and UPRmt ...

doi.org

A single S-ketamine injection enhances mTOR signaling in rat skeletal muscle - Journal of Muscle Research and Cell Motility

S-ketamine is recognized as a rapid-acting antidepressant, exerting its effects primarily through activation of the mTOR signaling pathway in the brain, which plays a key role in neuroplasticity. Give...

doi.org

Festschrift for Professor Jennifer Morgan - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility -

doi.org

Regulation of Autonomic Motility in Human Gastric Muscle and the Gastroepiploic Artery by Stretch and pH - Journal of Muscle Research and Cell Motility

Human gastric motility is regulated by both slow wave activity and membrane excitability. Regulation of gastric function involves adapting motility through repetitive stretches during feeding and digestion. Alongside gastric motility, gastric vascular motility must also be accurately regulated. The physiological function of stretch-activated K+ channels has been demonstrated in the relaxation mechanisms of the uterus and bladder. For these reasons, this study was designed to investigate whether stretch-activated K+ channels are involved in the functional regulation of human gastric muscle and vessels. We examined human gastric body tissues and gastroepiploic arteries from patients who underwent gastrectomy using a conventional contractile measurement system and Western immunoblot. High concentrations of K+ (50 mM) induced tonic contraction (4 g) in human gastric circular muscle from the body. Acetylcholine (ACh, 10 µM) also induced an initial peak (3 g), tonic (1.1 g), and phasic contractions (1.5 g; 2.5 cycles/min). L-methionine, known to block TWIK (two-pore domain weak inward rectifying K2P channel)-related K+ channels (TREK-1), produced sustained contraction (2 g) in gastric smooth muscle in the presence of a cocktail of K+ channel blockers. Additionally, channel inhibitors such as extracellular acidosis (MES ([pH]o = 6.4)), quinidine, bupivacaine, and lidocaine enhanced spontaneous contractions by 224%, 183%, 138%, and 127% of control, respectively, in the presence of L-methionine. Concurrently, we analyzed the physiological role of TREK-1 and TASK-2 in the human gastroepiploic artery. The ring of the human gastroepiploic artery produced tonic contraction (2.8 g) under high K+ (50 mM). Following stimulation with high K+, the artery exhibited spontaneous vasoconstriction known as vasomotion (2.7 g; 0.13 cycles/min), which was completely inhibited by nifedipine, a voltage-dependent L-type Ca2+ channel (VDCCL) blocker. BayK 8644, an activator of VDCCL, induced vasomotion, which was also inhibited by nifedipine. In the human artery, L-methionine induced a vascular tonic contraction (0.15 g) and enhanced vasomotion by 179%. Additionally, lidocaine induced peak and tonic contractions of 1 g and 0.7 g, respectively. Both L-methionine and lidocaine also enhanced vasomotion induced by BayK 8644. The molecular presence of TREK-1 and TASK-2 was confirmed via Western blot in human gastric muscle, gastric mucosa, and artery, respectively. These findings suggest that TREK-1 and TASK-2 may be significant regulators of human gastric muscle and vascular motility.

doi.org

LncRNA Xist acts as a miR-486-5p sponge to modulate myoblast proliferation by recruiting Stk4 - Journal of Muscle Research and Cell Motility

Cell proliferation plays a crucial role in muscle atrophy-regeneration. However, the functional roles of Long non-coding RNA X-inactive specific transcript (lncRNA Xist) in C2C12 cell proliferation re...

doi.org

Smooth muscle of the lower urinary tract: BK-RyR coupling in physiology and pathophysiology - Journal of Muscle Research and Cell Motility

In the lower urinary tract, coordinated function between the bladder and urethra is essential for normal micturition, requiring smooth muscle contraction and relaxation in a tightly regulated cycle. D...

doi.org

Skeletal muscle alterations in Marfan syndrome: a systematic review - Journal of Muscle Research and Cell Motility

Marfan syndrome is an autosomal dominant multisystemic connective tissue disorder caused by mutations in the FBN1 gene. Although clinical changes in the cardiovascular, ocular, and skeletal systems ha...

doi.org

Myoblast and fibroblast derived small extracellular vesicles differentially affect myoblast migration dynamics - Journal of Muscle Research and Cell Motility

Muscle injury activates satellite cells and fibroblasts, with extracellular vesicles (EVs) mediating the related intercellular communication. The influence of EVs released by either cell type on recip...

doi.org

Smooth muscle cells from skin perforator vessels as a new tool for vascular research - Journal of Muscle Research and Cell Motility

Vascular smooth muscle cells (SMC) comprise the medial layer of blood vessels and are responsible for maintaining vascular tone. Ordinarily quiescent and contractile, SMC can dedifferentiate into diff...

doi.org

Regulation and function of Pax3 in muscle stem cell heterogeneity and stress response - Journal of Muscle Research and Cell Motility

Journal of Muscle Research and Cell Motility -

doi.org

Residual force enhancement following hindlimb unloading and exercise prehabilitation - Journal of Muscle Research and Cell Motility

This study was performed to investigate the effect of exercise prehabilitation (EPH) on passive force, residual force enhancement (RFE), and muscle protein expression in rat skeletal muscle. A total o...

doi.org