Muscle-skeletal chains

Sarcopenia is a major contributor to disability in older adults, and thus, it is key to elucidate the mechanisms underlying its development. Increasing evidence suggests that impaired macroautophagy/autophagy contributes to the development of sarcopenia. However, the mechanisms leading to reduced autophagy during aging remain largely unexplored, and whether autophagy activation protects from sarcopenia has not been fully addressed. Here we show that the autophagy regulator TP53INP2/TRP53INP2 is decreased during aging in mouse and human skeletal muscle...

AIMS: Although there is evidence that stroke patients who exercise regularly before stroke have a better prognosis than those who do not exercise, the detailed mechanism remains unclear. Moreover, neuronal death plays a central role in neurological dysfunction caused by ischemic stroke. Thus, we investigated whether exercise could reduce stroke-induced neuronal death and its associated mediators in the current study. RESULTS: Ferroptosis was the most dominant form of programmed cell death in neurons...

The low efficiency of in vivo transfection of a few fibres revealed a novel tissue network that temporally amplified growth stimulation in the entire regenerating rat soleus muscle. This acupuncture-like effect was demonstrated when the fibres began to grow after complete fibre degradation, synchronous inflammation, myoblast and myotube formation. Neonatal sarcoplasmic/endoplasmic reticulum ATPase (SERCA1b) was first detected in this system. The neonatal, fast and slow SERCA isoforms displayed consequent changes with innervation and differentiation, recapitulating events in muscle development...

Viperid snake venoms induce severe tissue damage, characterized by the direct toxic action of venom components, i.e., phospholipases A2 (PLA2 s) and metalloproteinases (SVMPs), concomitantly with the onset of endogenous inflammatory processes, in an intricate scenario of tissue alterations. Understanding the expression of relevant genes in muscle tissue will provide valuable insights into the undergoing pathological and inflammatory processes. In this study, we have used the Nanostring technology to evaluate the patterns of gene expression in mouse skeletal muscle 1 h, 6 h, and 24 h after injection of the venoms of Bothrops asper and Daboia russelii , two medically relevant species in Latin America and Asia, respectively, with somewhat different clinical manifestations...

Muscle atrophy is a detrimental and injurious condition that leads to reduced skeletal muscle mass and disruption of protein metabolism. Oyster ( Crassostrea nippona ) is a famous and commonly consumed shellfish in East Asia and has become a popular dietary choice worldwide. The current investigation evaluated the efficacy of C. nippona against muscle atrophy, which has become a severe health issue. Mammalian skeletal muscles are primarily responsible for efficient metabolism, energy consumption, and body movements...

Cytochrome c (Cyt c ) has both life-sustaining and cellular death-related functions, depending on subcellular localization. Within mitochondria, Cyt c acts as a single electron carrier as part of the electron transport chain (ETC). When released into the cytosol after cellular insult, Cyt c triggers the assembly of the apoptosome, committing the cell to intrinsic apoptosis. Due to these dual natures, Cyt c requires strong regulation by the cell, including post-translational modifications, such as phosphorylation and acetylation...

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, which is commonly associated with NAFLD. Adenosine-to-inosine editing, catalysed by adenosine deaminase acting on RNA (ADAR), is an important post-transcriptional modification of genome-encoded RNA transcripts. Three ADAR gene family members, including ADAR1, ADAR2 and ADAR3, have been identified...

Plasma apelin levels are reduced in aging and muscle wasting conditions. We aimed to investigate the significance of apelin signaling in cardiac and skeletal muscle responses to physiological stress. Apelin knockout (KO) and wild type (WT) mice were subjected to high intensity interval training (HIIT) by treadmill running. The effects of apelin on energy metabolism were studied in primary mouse skeletal muscle myotubes and cardiomyocytes. Apelin increased mitochondrial ATP production and mitochondrial coupling efficiency in myotubes and promoted the expression of mitochondrial genes both in primary myotubes and cardiomyocytes...

Long non-coding RNAs (lncRNAs) play an essential role in vertebrate myogenesis and muscle diseases. However, the dynamic expression patterns, biological functions, and mechanisms of lncRNAs in skeletal muscle development and regeneration remain largely unknown. In this study, a novel lncRNA (named lncMGR) was differentially expressed during breast muscle development in fast- and slow-growing chickens. Functionally, lncMGR promoted myoblast differentiation, inhibited myoblast proliferation in vitro, and promoted myofiber hypertrophy and injury repair in vivo...

High-intensity exercise stimulates glycolysis, subsequently leading to elevated lactate production within skeletal muscle. While lactate produced within the muscle is predominantly released into the circulation via the monocarboxylate transporter 4 (MCT4), recent research underscores lactate's function as an intercellular and intertissue signalling molecule. However, its specific intracellular roles within muscle cells remains less defined. In this study, our objective was to elucidate the effects of increased intramuscular lactate accumulation on skeletal muscle adaptation to training...

OBJECTIVE: Stroke is frequently associated with muscle mass loss. Treadmill training is considered the most effective treatment for sarcopenia. Circadian rhythms are closely related to exercise and have been extensively studied. The skeletal muscle has its molecular clock genes. Exercise may regulate skeletal muscle clock genes. This study evaluated the effects of early treadmill training on the skeletal muscle molecular clock machinery in rats with stroke and determined the relationship of these changes with exercise-induced improvements in skeletal muscle health...

Many human tissues exhibit a highly oriented architecture that confers them with distinct mechanical properties, enabling adaptation to diverse and challenging environments. Hydrogels, with their water-rich "soft and wet" structure, have emerged as promising biomimetic materials in tissue engineering for repairing and replacing damaged tissues and organs. Highly oriented hydrogels can especially emulate the structural orientation found in human tissue, exhibiting unique physiological functions and properties absent in traditional homogeneous isotropic hydrogels...

Sarcopenia is a progressive and generalized loss of skeletal muscle and functions associated with ageing with currently no definitive treatment. Alterations in gut microbial composition have emerged as a significant contributor to the pathophysiology of multiple diseases. Recently, its association with muscle health has pointed to its potential role in mediating sarcopenia. The current review focuses on the association of gut microbiota and mediators of muscle health, connecting the dots between the influence of gut microbiota and their metabolites on biomarkers of sarcopenia...

The molecular mechanisms underlying muscular adaptations to concentric, and eccentric exercise training have been extensively explored. However, most previous studies have focused on subjectively selected proteins, thus, unable to provide a comprehensive protein profile, and potentially missing the crucial mechanisms underlying muscular adaptation to exercise training. We herein aimed to investigate proteomic profiles of human skeletal muscle in response to short-term resistance training. Twenty young males were randomly and evenly assigned to two groups to complete a four-week either eccentric (ECC) or concentric (CON) training program...

The sleep-breathing condition obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse, which can exacerbate oxidative stress and free radical generation, thereby detrimentally impacting both motor and sensory nerve function and inducing muscular damage. OSA development is promoted by increasing proportions of fast-twitch muscle fibers in the genioglossus. Orientin, a water-soluble dietary C-glycosyl flavonoid with antioxidant properties, increased the expression of slow myosin heavy chain (MyHC) and signaling factors associated with AMP-activated protein kinase (AMPK) activation both in vivo and in vitro ...

Muscle contraction is a regulated process driven by the sliding of actin-thin filaments over myosin-thick filaments. Lmod2 is an actin filament length regulator and essential for life since human mutations and complete loss of Lmod2 in mice lead to dilated cardiomyopathy and death. To study the little-known role of Lmod2 in skeletal muscle, we created a mouse model with Lmod2 expressed exclusively in the heart but absent in skeletal muscle. Loss of Lmod2 in skeletal muscle results in decreased force production in fast- and slow-twitch muscles...

AIM: To explore the effects and mechanisms of different concentrations of uric acid on skeletal muscle cells. METHODS: C2C12 myoblasts were differentiated into myotubes and then exposed to a medium containing uric acid (0 μM, 200 μM, 400 μM, 600 μM, 800 μM, 1000 μM, 1200 μM, 1400 μM). The myotube diameters were observed under light microscopy; the expressions of myosin heavy chain (MyHC), autophagy-related proteins (LC3BII/LC3BI, P62), cGAS, and p-Sting/Sting proteins were analyzed using Western blotting or immunoprecipitation; and oxidative stress and mitochondrial damage were evaluated using ROS, mtDNA and JC-1 assays...

BACKGROUND: Skeletal craniofacial morphology can be influenced by changes in masticatory muscle function, which may also change the functional profile of the muscles. OBJECTIVES: To investigate the effects of age and functional demands on the expression of Myosin Heavy-Chain (MyHC) isoforms in representative jaw-closing and jaw-opening muscles, namely the masseter and digastric muscles respectively. METHODS: Eighty-four male Wistar rats were divided into four age groups, namely an immature (n = 12; 4-week-old), early adult (n = 24; 16-week-old), adult (n = 24; 26-week-old) and mature adult (n = 24; 38-week-old) group...

Lipin-1 is a member of the evolutionarily conserved family of proteins and is expressed predominantly in adipose tissue and skeletal muscle. On the one hand, lipin-1 is an enzyme that catalyzes the dephosphorylation of phosphatidic acid to diacylglycerol (DAG) and thus participates in the metabolic pathways of biosynthesis of storage lipids in the cell, membrane phospholipids, and intracellular signaling molecules. On the other hand, lipin-1 is able to be transported from the cytoplasm to the nucleus and is a coactivator of lipid metabolism gene transcription...

BACKGROUND: The diagnosis of myasthenia gravis (MG) in children remains difficult. Circulating small extracellular vesicle (sEV)-derived miRNAs (sEV-miRNAs) have been recognized as biomarkers of various diseases and can be excreted by different cell types. These biomarker candidates also play a vital role in autoimmune diseases via intercellular communication. METHODS: In the present study, we used sEV isolation and purification methods to extract the plasma-derived sEV-miRNAs from children with MG and healthy controls...