Search Results (959)

Background/Objectives: This study systematically investigated the expression characteristics of the ALDOA gene in skeletal muscle cells and its effects on cell proliferation, apoptosis, and differentiation. Methods: We constructed an ALDOA overexpression vector and transfected it into C2C12 cells and porcine skeletal muscle satellite cells. Results: We found that ALDOA exhibited the highest expression in the longissimus dorsi muscle and was primarily localized in the cell nucleus. Overexpression of ALDOA significantly inhibited cell proliferation, induced G0/G1 phase arrest, and downregulated the expression of proliferation-related genes such as CDK2 and Cyclin D1. Concurrently, ALDOA overexpression markedly promoted apoptosis. Regarding differentiation, although ALDOA expression was upregulated during differentiation, its overexpression significantly suppressed the expression of myogenic differentiation-related genes (such as MYOD, MYOG, MEF2C), suggesting a negative regulatory role in differentiation control. Conclusions: This study reveals the multifaceted regulatory functions of ALDOA in skeletal muscle cells, providing experimental evidence for deepening the understanding of its mechanisms in muscle development and regeneration. This study provides the first functional evidence that ALDOA acts as a multifunctional regulator in skeletal muscle cells, negatively governing cell growth and fate decisions by inhibiting proliferation, promoting apoptosis, and impeding myogenic differentiation, thereby extending its role beyond glycolysis to direct governance of cellular processes. This study reveals for the first time that ALDOA possesses dual functions in muscle cells, regulating both metabolism and transcription. Full article

Magnesium (Mg²⁺) is a key regulator of cellular biochemical processes and an essential cofactor in skeletal muscle physiology. Although Mg²⁺ deficiency has been linked to reduced muscle strength, its role in the regulation of calcium (Ca²⁺) signaling and in inflammation remains incompletely understood. In this study, we examined the effects of Mg²⁺ availability using the murine myoblast cell line C2C12. Cells were differentiated under low, normal, or high Mg²⁺ conditions, and myotube formation, intracellular Ca²⁺ fluxes, and resistance to inflammatory stimuli were assessed. Mg²⁺ deficiency impaired myotube differentiation, while Mg²⁺ supplementation preserved Ca²⁺ response during stimulation and contributed to protect myotubes against inflammation-induced damage. Collectively, these findings highlight a dual role of Mg²⁺ in sustaining functional performance under repeated stress and protecting myotubes against inflammatory injury. This study supports the importance of adequate dietary Mg²⁺ intake as a potential strategy to mitigate muscle loss associated with aging and chronic inflammation. Full article

We have previously established that bexarotene, a clinically approved agonist of retinoid X receptor (RXR), promotes the differentiation and fusion of skeletal myoblasts. We have also analyzed the genomic programs underlying rexinoid-enhanced myogenic differentiation to identify novel regulatory pathways. As such, we observed a significant upregulation of a transcript encoding a predicted transmembrane protein, Tmem182, during C2C12 myoblast differentiation. Despite the documentation of Tmem182 expression in skeletal muscles, its regulation had yet to be explored. Here, we show that Tmem182 gene expression is markedly augmented in early myoblast differentiation and further enhanced by RXR signaling. In addition, Tmem182 expression is specific to muscle tissues and related to muscle master regulator MyoD. We found that MyoD and histone acetyltransferase p300 are bound to the Tmem182 promoter, and Tmem182 expression is p300-dependent. Thus, our data display a putative epigenetic signature associated with p300 and histone acetylation in rexinoid-responsive locus activation and transcription of myogenic targets. Full article

Background/Objectives: Alcohol use disorder (AUD) is a major public health issue with rising global occurrence and metabolic consequences. Modeling the addictive behaviors associated with AUD remains inadequate and elusive. Even more so, models that are representative of AUD in concert with excessive caloric intake are limited. Some consequences of chronic alcohol use overlap with the metabolic phenotype of hypercaloric diets. Recently characterized metabolic dysfunction-associated steatotic liver disease with increased alcohol intake (MetALD) helps to differentiate these conditions. This study aims to investigate metabolic phenotypes and gene expression alterations in MetALD mice that are grouped by alcohol preference based on blood phosphatidylethanol levels and alcohol consumption. Methods: Mice were fed high-fat and chow diets, with water and 10% EtOH, for 13 weeks. mRNA sequencing was performed across multiple tissues including brain, liver, skeletal muscle, ileum, and white adipose tissue, and gut microbiome diversity was evaluated via 16S sequencing. Results: Key findings included reduced glucagon in alcohol-preferring mice with no significant differences in dyslipidemia and hepatic steatosis. Additionally, we observed reduced gut microbiome diversity and Wnt signaling with elevated acute-phase response genes in ileum tissue. Reduced Wnt and Hippo signaling in the brain and liver, respectively, was also revealed. Other gene ontologies discovered included increased neural inflammation and adipose mitochondrial translation. Nek3, Ntf3, Cux1, and Irf6 expression changes were shared across at least three tissues and may be potential biomarkers of alcohol addiction. Conclusions: This novel model assists future intervention research in the characterization of MetALD and identifies potential biomarkers of alcohol preference. Full article

Skeletal muscles are essential for movement and support but are vulnerable to injury. Muscle regeneration relies on the extracellular matrix (ECM), which regulates key cellular processes. Transforming growth factor β-induced (TGFBI), an ECM component involved in cell adhesion, migration, and tissue development, has not been investigated in skeletal muscle regeneration. Here, we examined the role of TGFBI using Tgfbi knockout (KO) mice and C2C12 myoblasts. In vitro, C2C12 cells were treated with recombinant TGFBI following snake venom (SV)-induced injury, and myogenic differentiation and fusion were evaluated by quantitative real-time PCR (qRT-PCR) and Western blotting. In vivo, acute muscle injury was induced by SV injection into the tibialis anterior muscles of 12-week-old wild-type and Tgfbi KO mice, with regeneration assessed by histology and qRT-PCR. TGFBI was absent in uninjured muscle and C2C12 cells but was upregulated after injury. Recombinant TGFBI enhanced myogenic differentiation and restored SV-induced downregulation of myogenic and fusion markers. Although phenotypically normal under physiological conditions, Tgfbi KO mice exhibited impaired regeneration, characterized by persistent immature myofibers, elevated inflammatory cytokines, reduced myogenic marker expression, and increased fibrosis. These findings reveal TGFBI as a key regulator of skeletal muscle repair and a potential therapeutic target for muscle-related disorders. Full article

Mesenchymal stromal/stem cells (MSCs) are known to secrete a wide range of pleiotropic molecules promoting tissue repair and regeneration. Recent advances in cell sheet technology have demonstrated significant improvements in the regenerative capacity of MSCs within the sheet, retaining appropriate microenvironmental cues, and have suggested an instructing role of extracellular matrix (ECM). We previously found that the secretome of MSCs cultured on a decellularized MSC-derived ECM (dECM) was significantly enriched in dozens of cytokines, chemokines and growth factors compared to the secretome of MSCs grown on standard plastic dishes. The enriched secretome has been shown to have enhanced chemotactic and angiogenic properties, stimulate C2C12 myoblast proliferation and promote skeletal muscle regeneration in a murine in vivo model. Here, we report novel findings about dECM-induced changes in the miRNA profile of MSCs. We performed miRNA-seq and found 17 differentially expressed miRNAs in endometrial MSCs (MESCs) with miR-146a-5p being the most upregulated. Additionally, we investigated miR-146a-5p expression in MSCs of various origins after exposure to dECM, and found a correlation between miR-146a-5p upregulation and the general dECM-induced paracrine response. Furthermore, we demonstrated that miR-146a-5p mimics, transfected into C2C12 myoblasts, promoted their proliferation, suggesting a role for miR-146a-5p in myotropic effects mediated by the enriched secretome. These findings provide new insights into how ECM as a component of the MSC niche influences the secretory phenotype and modulates therapeutic properties of MSCs. Full article

Circular RNA (CircRNA) can regulate gene expression through acting as a competitive endogenous RNA (ceRNA), thus becoming involved in various biological processes. However, little was known about the role of circRNA in the formation of meat quality in pigs. Here, circRNAs were first characterized in muscles with differential meat quality and myofiber composition, longissimus thoracis, and semitendinosus muscles, with RNA-sequencing (RNA-seq). A total of 1126 differentially expressed circRNAs were identified. Among them, Circ-06958 is highly expressed in both muscles. Circ-06958 originated from Long-chain acyl-CoA synthetase 1 (ACSL1), a gene involved in muscle development. Circ-06958 was then characterized experimentally for the first time. Next, it was revealed that Circ-06958 increased proliferation of muscle cells, including porcine skeletal muscle satellite cells (PMSCs) and C2C12 myoblasts, by promoting cell cycle progression. Circ-06958 was mainly localized in cytoplasm, indicating it can function as a ceRNA. A regulatory axis Circ-06958/miR-31-5p/Adenylate Kinase 4 (AK4) axis was constructed with molecular biology techniques. Afterward, it was shown that miR-31-5p inhibited cell proliferation by affecting cell cycle progression in the two cells, while AK4 increased it. We made it clear that Circ-06958 promoted muscle cell proliferation via the miR-31-5p/AK4 axis. The results will contribute to further revealing the mechanisms through which meat quality generates. Full article

Long non-coding RNAs (lncRNAs) are essential regulatory molecules involved in various biological processes in mammals. However, their expression patterns across multiple porcine tissues have not been systematically characterized. We analyzed 607 RNA-seq datasets derived from 14 porcine tissues, including backfat, gallbladder, heart, ileum, jejunum, kidney, longissimus dorsi, liver, lung, skeletal muscle, ovary, pituitary, skeletal muscle, and spleen. Additionally, we examined 63 single-cell RNA-seq datasets from porcine primary oocytes at five developmental stages. For comparative analysis, we included 20 human and 17 mouse oocyte RNA-seq datasets. We identified 52,798 porcine lncRNAs, with tissue-specific expression patterns most prominent in oocytes and least in skeletal muscle. Among them, 2169 were classified as housekeeping and 14,469 as tissue-specific lncRNAs. Cross-species analysis revealed that a small subset of oocyte-expressed lncRNAs is conserved in humans and mice, associated with catalytic activity and circadian regulation. Additionally, 44 lncRNAs were differentially expressed during oocyte development, implicating them in neurogenesis, vesicle transport, and protein modification. Our findings not only contribute to the growing body of knowledge regarding lncRNAs in porcine biology but also pave the way for future research aimed at elucidating their functional roles in reproductive biology and other physiological processes. Full article

The Kazakh horse, a versatile breed, is renowned for stable genetic performance and strong tolerance to coarse feed. Sex is a key factor influencing skeletal muscle development. However, the mechanisms underlying sex-specific regulation of equine muscle growth remain obscure. This study employed transcriptomic analysis to investigate sex-associated molecular differences in skeletal muscle of Kazakh horses. The experimental cohort comprised four three-year-old Kazakh stallions and four three-year-old Kazakh mares. After slaughter, six groups of muscle samples were collected immediately, including the longissimus dorsi, rectus abdominis, and diaphragm muscles of both sexes, with four biological replicates per group. RNA-seq analysis revealed 361, 230, and 236 differentially expressed genes (DEGs) in the longissimus dorsi of stallion Kazakh horses (Mb) vs. the longissimus dorsi of mare Kazakh horses (Gb), the rectus abdominis of stallion Kazakh horses (Mf) vs. the rectus abdominis of mare Kazakh horses (Gf), and the diaphragm of stallion Kazakh horses (Mg) vs. the diaphragm of mare Kazakh horses (Gg), respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that DEGs such as TPM1, MYL1, MYH3, and PYGM were primarily enriched in muscle system processes (BP), contractile fibers (CC), and adenosine ribonucleotide binding (MF). Furthermore, these genes were significantly associated with pathways such as the Cytoskeleton in muscle cells and the Thyroid hormone signaling pathway. The data demonstrate pronounced sex-related differences in gene expression and muscle structure in Kazakh horses, likely mediated by cytoskeleton-associated genes. Notably, TPM1, MYL1, MYH3, and PYGM may act as key regulators of sex-specific muscle development. These findings provide molecular insights into the mechanisms underlying sexual dimorphism in equine muscle growth. Full article

To investigate the genetic regulatory mechanism of supplementary feeding on muscle development in Oula sheep, we employed transcriptomic analysis to explore the differentially expressed genes (DEGs) in the longissimus dorsi muscle of Oula sheep at different ages under conditions of supplementary feeding and non-supplementary feeding, as well as the significantly enriched Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways of DEGs. Moreover, by combining with the method of weighted gene co-expression network analysis, we screened for the potential hub genes that might play crucial roles. The results demonstrated that the CD4 and ICAM1 genes and the PI3K-Akt signaling pathway might exert important functions during the lamb stage. At the growth stage, the AGL, PGM2L1, PRKAA2, NEDD4, and GBE1 genes might serve as core genes to regulate the growth of skeletal muscle in Oula sheep after supplementary feeding through signaling pathways such as starch and sucrose metabolism and insulin signaling pathway. This outcome provides a molecular-level interpretation of the regulatory mechanism of supplementary feeding on muscle growth and development in Oula sheep at different ages, offering a theoretical basis for the further improvement of the meat quality of Oula sheep and the enhancement of the quality of livestock products in the Qinghai–Tibet Plateau region. Full article

Skeletal muscle, the primary meat-producing tissue in bovines, is regulated by a complex transcriptional network during development. The role of Thrombospondin 3 (THBS3) and its associated super-enhancer (SE) in this process remains largely unknown. Here, by integrating multi-omics data, we identified THBS3 as a novel core regulator of myogenesis, orchestrated by a cognate super-enhancer (THBS3-SE). Functional assays demonstrated that THBS3 knockdown significantly promoted the proliferation and myogenic differentiation of bovine muscle stem cells (MuSCs) and accelerated their commitment to a fast-twitch fiber fate. Transcriptomic analysis linked THBS3 function to key signaling pathways controlling muscle growth, especially the mechanistic target of rapamycin (mTOR) signaling pathway. Mechanistically, we found that distal enhancers within the THBS3-SE loop to the THBS3 promoter drive its transcription, and CRISPR-based interference of these enhancers recapitulated the pro-myogenic effects of THBS3 knockdown. Collectively, our findings unveiled a THBS3-SE-mediated regulatory axis that critically governed bovine MuSCs’ fate. Targeting this axis may offer a novel strategy for improving beef production efficiency. Full article

Background: Glucose intolerance (GI) is a metabolic disorder that is a consequence of hyperglycemia. Glucose intolerance can, under some conditions, progress to type 2 diabetes mellitus (T2D), where insulin is insufficiently utilized. As a result of genetic and lifestyle effects, the incidence of T2D has increased worldwide. Pathophysiological consequences of the disease may include retinopathy, nephropathy, and neuropathy. Skeletal muscle is one of the major organs that regulates blood sugar homeostasis, both at rest and during exercise. Thus, understanding the molecular and genetic perspectives on the contribution of skeletal muscles to the predisposition to diabetes is a hot topic in diabetes research. In this study, we conducted a differential analysis of gene expression and compared the expression profiles of all the genes in the skeletal muscles of normal, glucose-intolerant, and diabetic individuals via the Affymetrix HGU133plus2 platform. Data were collected from the Gene-Expression Omnibus (GEO) series GSE18732. Gene Ontology enrichment and perturbed pathways were thoroughly analyzed. Results: We found that genes that were significantly differentially expressed between the different tissues contribute to metabolic pathways related to glucose homeostasis, as well as several signaling pathways related to insulin signaling, e.g., the MAPK, mTOR, Toll-like receptor (TLR), p53, WNT and neurotrophin signaling pathways. Furthermore, some genes related to several malignancies were also differentially expressed across the different clinical groups. Additionally, some of these genes are related to epigenetic regulation. Furthermore, other differentially expressed genes were connected to several myopathies. Conclusions: This study may serve as a gene-based analysis that contributes as a basis for further analysis. This investigation may include gene and protein networks that serve in understanding diabetes, the mechanism of action of the involved proteins, and pharmacology and drug design targeting T2D. Full article

The purpose of this experiment was to study the effects of heat stress on the performance and protein metabolism of skeletal muscle in meat rabbits. A total of 160 New Zealand White rabbits aged 80 days with mean initial body weights of 2359 ± 200 g were randomly divided into a control group and a heat stress group. The experiment duration was 20 days. Heat stress treatment reduced the growth performance and slaughter performance of the rabbits (p < 0.05) and increased muscle yellowness (b*, p < 0.05). In addition, heat stress treatment increased the concentrations of leptin, cholesterol, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol in serum (p < 0.05), and decreased the serum total protein and immunoglobulin (IgG, IgM, and IgA) contents of rabbits. Under the criteria fold-change ≥ 1.20 or ≤0.84 and p-value ≤ 0.05, 7 up-regulated proteins and 122 down-regulated proteins were screened. A gene ontology (GO) enrichment analysis of the differentially expressed proteins was performed. The most enriched specific GO terms among the differential proteins were response to stress, extracellular region, and protein binding in the biological process (BP), cellular component (CC), and molecular function (MF) categories, respectively, and the most enriched pathway was the PI3K/Akt signalling pathway. In conclusion, heat stress could reduce the carcass yield of meat rabbits, change the physical characteristics of the skeletal muscle, and influence protein metabolism by changing blood indices, potentially through the PI3K/Akt signalling pathway. Full article

N-lactoyl amino acids (Lac-AAs) are key players that regulate appetite and body weight. The most prominent and well-studied member is N-lactoyl phenylalanine (Lac-Phe), which can be induced by food intake, exercise and metformin treatment. However, its broader metabolic impact remains insufficiently characterized. This study investigates the effects of Lac-Phe on insulin signaling, inflammation, and mitochondrial respiration using HepG2 and differentiated C2C12 cell models, as well as isolated rat brain mitochondria and synaptosomes. Our results demonstrate that Lac-Phe significantly impairs insulin-stimulated phosphorylation of key proteins in the insulin signaling pathway, particularly in skeletal muscle cells, indicating disrupted insulin signaling. Additionally, Lac-Phe exposure increases the secretion of pro-inflammatory cytokines in C2C12 skeletal muscle cells and markedly impairs mitochondrial respiration in HepG2 liver cells and rat brain-derived synaptosomes, but not in isolated mitochondria. These findings highlight potential adverse metabolic effects of Lac-Phe, especially when administered at high concentrations, and underscore the necessity of conducting a comprehensive risk assessment and dose optimization before considering Lac-Phe or related Lac-AAs as therapeutic agents. Our work provides important insights into the molecular liabilities associated with Lac-Phe and calls for further studies to balance its therapeutic promise against possible metabolic risks. Full article

Sarcopenia, the age-related decline in skeletal muscle mass and function, is a growing health concern in aging populations. Nutritional interventions are increasingly recognized for their therapeutic potential; however, molecular biomarkers that reflect their efficacy are limited. To identify nutrition-responsive genes relevant to sarcopenia, we performed transcriptomic profiling of gastrocnemius muscle from mature and middle-aged mice. Aging-associated differentially expressed genes (DEGs) were filtered based on expression levels and correlation with muscle mass. Functional food interventions, including high- and low-molecular-weight collagen hydrolysates and allulose, were applied, and effect scores were calculated to assess transcriptomic responsiveness. Ajuba, a gene involved in cytoskeletal regulation and tissue remodeling, was significantly downregulated in middle-aged mice, consistent with aging-associated muscle decline. Dietary supplementation restored Ajuba expression across all intervention groups, with the strongest effect observed in the high-molecular-weight collagen group. Ajuba expression also showed strong positive correlations with tibialis anterior mass, hindlimb thickness, and muscle-to-fat ratio. Ajuba was identified as a nutritionally modifiable gene with strong associations to muscle phenotype and dietary response. These findings support Ajuba as a transcriptomic biomarker and potential molecular target for precision nutrition strategies aimed at preventing or mitigating sarcopenia. Full article