GDF-8 (Myostatin)

Abstract

Skeletal muscles secrete myokines, including irisin and myostatin, which regulate inflammation and metabolism and may influence the severity of SARS-CoV-2 infection. This study investigated the associations between serum irisin and myostatin levels and COVID-19 severity.

Abstract

The myostatin protein is a potent negative regulator of skeletal muscle growth encoded by the MSTN gene. MSTN loss-of-function variants lead to a particular cattle phenotype characterized by an increase in skeletal muscle mass, known as "double muscling" or "double muscled". However, most of the MSTN causal variants that have been linked to this phenotype lack experimental validation. This is the case, for example, for the five missense MSTN variants reported to be causal according to the Online Mendelian Inheritance in Animals. RNA splicing plays a major role in regulating gene expression; therefore, exploring the effects of variants on RNA splicing may provide relevant information on their functional impact. Here, we have set up a full-length gene assay (FLGA) to functionally assess MSTN splicing variants, and we have used it to test the five missense variants plus a well-described deep intronic splicing variant as a positive control. We also evaluated the performances of SpliceAI and Pangolin, two deep learning-based splice predictors, to identify potential splicing effects of these six variants. Our FLGA system performed well and showed that none of the missense variants has an effect on splicing, unlike the positive control. For each variant, splicing program predictions were perfectly concordant with the effect observed in the FLGA. We have produced a relevant and powerful assay to analyze MSTN splicing variants in cattle. SpliceAI and Pangolin may be efficiently used to screen large datasets of MSTN variants and sort the best candidates prior to experimental validation using an FLGA.

Abstract

Mastication is essential for oral function and systemic metabolic regulation. The impact of soft diets, which reduce masticatory load, on myokine signaling remains unclear. Accordingly, we examined whether reduced mastication alters myokine secretion from the masseter muscle and affects muscle development and systemic metabolic regulation. Male C57BL/6J mice were fed either hard or soft diets for short-term (1 week) or long-term (7 weeks). Body weight, masseter muscle weight, epididymal fat weight, and fiber cross-sectional area were assessed. The expression of key myokines (IL-6, IL-10, TNF-α, Nfkb1, and myostatin [Mstn]) was measured using qPCR (quantitative polymerase chain reaction), and myostatin protein levels were evaluated using immunohistochemical assays. Short-term soft diet feeding did not produce any major morphological changes. However, long-term feeding significantly reduced masseter weight and fiber size, while increasing the amount of epididymal fat, despite an unchanged total body weight. At the molecular level, IL-6 expression was consistently lower in soft diet-fed mice, and IL-10 levels declined further with long-term feeding. In contrast, TNF-α, Nfkb1, and Mstn levels were elevated at both ages. The immunohistochemical assays confirmed increased myostatin protein levels in the masseter under soft-diet conditions. These results suggest that reduced masticatory stimulation remodels the biochemical environment of the masseter muscle, suppressing anabolic and anti-inflammatory signals while enhancing catabolic pathways. These alterations impair muscle growth and promote fat accumulation indicating that masticatory load regulates craniofacial muscle development and systemic metabolism through myokine-mediated mechanisms. Therefore, maintaining adequate mastication during growth may be critical for oral health, body composition, and long-term metabolic homeostasis.

Abstract

Portunus trituberculatus is an economically important marine crustacean in East Asia's aquaculture industry. Nevertheless, precise genome modification has not yet been established. In this study, we evaluated the applicability of the CRISPR-Cas9 gene editing system in P. trituberculatus using electroporation for efficient delivery of the Cas9-sgRNA complex into zygotes. We systematically investigated electroporation parameters, including buffer composition, voltage, capacitance, and pulse times. Our results showed that artificial seawater was a superior buffer to phosphate-buffered saline (PBS) and identified an effective electroporation condition of 600 V, 1 μF capacitance, and two pulses, resulting in approximately 72.7% fluorescent zygotes. Under these electroporated conditions, we detected gene indels and putative insertion events at the targeted locus of myostatin (mstn) gene. These results demonstrate the feasibility of Cas9-based genome editing in P. trituberculatus and provide a proof-of-concept for functional genomics studies and future genetic improvement of this species.

Abstract

Obesity is increasingly recognized not only as a metabolic disorder but also as a condition marked by the structural and functional deterioration of skeletal muscle and tendon tissues. Central to this process is the dysregulation of the extracellular matrix (ECM) resulting in fibrosis and ectopic fat accumulation, factors that contribute to impaired tissue mechanics. Myostatin (GDF-8), a member of the TGF-β superfamily, is known as a negative regulator of muscle mass. It can also mediate interaction between adipose and other tissues including muscles and tendons. In obesity, elevated myostatin levels have been reported to be associated with insulin resistance, muscle atrophy, and activation of SMAD2/3 signaling, while experimental and preclinical studies indicate that myostatin inhibition can improve glucose homeostasis and increase lean mass. Emerging evidence suggests that myostatin also plays a critical role in muscle ECM and tendon remodeling. Restoring its physiological levels may help reverse ECM disorganization and reduce tissue fragility associated with musculotendinous dysfunction. This review highlights the multifaceted role of myostatin in obesity, beyond its role in muscle catabolism, to include modulation of structural integrity, metabolism, and mechanical adaptability of the musculotendinous system. Understanding how myostatin responds to metabolic stress and affects biomechanical remodeling offers novel insights into obesity-related muscle and tendon dysfunction.

Abstract

Cattle breeds are optimized either for milk or meat production and secrete consumed nutrients in the form of milk or accrete nutrients as skeletal muscle tissue, respectively. Surplus energy is usually stored in the form of fat in adipose tissues. To gain more insight into the physiological and genetic background of nutrient accretion as either protein or fat, an experimental F2 population was generated crossing Charolais (CH) bulls and German Holstein (GH) cows. Mutations in two genes with known, profound effects on growth were segregating in this population: the I442M mutation in the non-SMC condensin I complex, subunit G (NCAPG) gene, and the Q204X mutation in the myostatin (MSTN) gene. The major aim of this study was to close the gap between the described effects of the NCAPG/LCORL region and MSTN SNPs on carcass and meat quality traits, as well as on the structure and composition of the underlying tissues. Whole carcass data, meat quality traits, composition of major cuts and their dominating muscles, including muscle and fat cell structure, were analyzed as well as chemical and fatty acid composition. Mutant alleles of both loci were associated with higher weights, increased muscularity, and reduced fatness, e.g., each explaining about 15% of the observed variance. However, both loci apparently affect traits in a specific manner, influencing either dimensional traits or mass accretion.

Abstract

Glucagon-like peptide-1 (GLP-1) receptor and dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonists drive significant transformation in the landscape for type 2 diabetes and obesity management, yet 15-40% of weight loss in trials like STEP and SURMOUNT stems from lean muscle mass. This catabolic loss impairs glucose disposal, muscle strength, and physical function; elevating risks for the loss of force generating capacity in the skeletal muscles leading to sarcopenia, particularly in elderly patients. Unfortunately, current FDA guidelines emphasize total weight reduction over body composition, featuring an unmet critical need for elucidating strategies to preserve loss of lean muscle. This review will feature the emerging therapeutics to mitigate loss of lean muscle, including selective androgen receptor modulators, myostatin-targeting TGF-β inhibitors, and gene-silencing siRNA therapies. Despite promising preclinical and early clinical data, limitations persist, including reliance on parenteral biologics, limited mechanistic diversity, short trial durations, and sparse functional outcome data. Future research must prioritize precise muscle assessments, body composition, long-term trials, and accessible interventions integrating pharmacotherapy. These advances could redefine weight loss paradigms, ensuring therapeutic efficacy aligns with optimal body composition and patient outcomes.

Abstract

Background: Myokines are secreted by skeletal muscle and play a role in their metabolic function and crosstalk with various tissues. Myokines appear to be involved in the pathogenesis of obesity and type 2 diabetes (T2D), yet little is known regarding their function in type 1 diabetes (T1D). Aim: To assess the levels and clinical correlates of a panel of five myokines, comparing adolescents with recent-onset T1D, prolonged disease, and healthy controls. Methods: Fifty-eight adolescents participated; 20 with recent-onset T1D, 20 with over 7 years of T1D, and 18 healthy controls were included. Clinical and laboratory data were collected, including levels of Apelin, Irisin, Interleukin-6 (IL-6), Fibroblast growth factor 21 (FGF21), and Myostatin. Results: Apelin levels were lower in patients with prolonged T1D compared with patients with recent-onset T1D and controls, (117.9 ± 94.3, 228.3 ± 181.6, and 224.4 ± 138.4 pg/ml, respectively; analysis of variance (ANOVA) p = 0.029). Other myokines did not differ significantly between groups. Apelin levels correlated with fasting C-peptide levels (r = 0.337, p = 0.010). In patients with prolonged T1D, myostatin positively correlated with insulin doses (total daily dose r = 0.590, p = 0.006 and basal daily dose r = 0.645, p = 0.002). Both apelin and myostatin levels negatively correlated with the diastolic blood pressure (BP) percentile (r = - 0.324, p = 0.013; r = - 0.302, p = 0.024, respectively). Conclusions: Our results demonstrate lower levels of apelin, a myokine related to the beneficial metabolic effects of skeletal muscle, in prolonged T1D. The correlations of apelin with C-peptide and myostatin with insulin doses may reflect a relationship with beta-cell function and insulin sensitivity.

Abstract

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are used to treat obesity and metabolic diseases, yet their early impact on body composition and circulating regulators of muscle and bone remain unclear. This study aimed to assess early effects of liraglutide on total and regional body composition and associated changes in circulating markers of muscle and bone metabolism.

Abstract

Studies have shown that sarcopenia and its related parameters are associated with cognition. Preclinical evidence suggests that myokines, such as irisin, Brain-Derived Neurotrophic Factor(BDNF), myostatin and Insulin-like Growth Factor-1(IGF-1) might explain this relationship. This study aimed to explore the associations between sarcopenia-related parameters and cognition, and whether myokines influence this association.

Abstract

Sarcopenia and obesity are major global health challenges. This study investigated peptides from chicken breast meat via in vitro digestion as potent ActRIIB antagonists to promote myogenesis. The intestinal-phase digest collected at 120 min showed the highest degree of hydrolysis (65.99 % ± 4.00 %) and enhanced C2C12 proliferation (128.15 % ± 9.90 %). Peptidomics identified peptides mainly from myofibrillar proteins and metabolic enzymes. Molecular docking revealed key hydrogen-bonding residues, including Glu95, Pro117, Glu94, Thr93, Asn96 (Chain A), Ser97 (Chain L), and Ser59 (Chain H). Surface plasmon resonance showed that KEKLHVYKHIEK, EIKKEEKKEER, and DLENDKQQLDEK exhibited strong ActRIIB-binding affinity (KD: 0.514, 0.813, 1.91 μM). These peptides enhanced cell proliferation, inhibited myostatin signaling by reducing Smad2/3 phosphorylation, and upregulated MyoD expression. Molecular dynamics simulations (100 ns) indicated that DLENDKQQLDEK-ActRIIB and EIKKEEKKEER-ActRIIB complexes maintained a stable average number of 6 and 10 hydrogen bonds, respectively. Chicken breast-derived peptides thus represent promising functional food ingredients for combating muscle-wasting disorders.

Abstract

Gene expression levels of myogenic regulatory factors (MRFs) (myf5, myod2, and myog), myostatin (mstn1a and mstn1b), and the muscle protein myosin (myhc) in muscles were studied in the rainbow trout Oncorhynchus mykiss Walb. Study fish of three size groups (SGs) were fed with two commercial feeds differing in compositions. Expression levels of myhc, myf5, myog, and mstn1a in muscles were found to differ depending on the feed, especially in smaller fish (<1000 g). The finding suggests that the feed composition, including the quantitative ratio of ingredients and the sources of proteins, fats, and carbohydrates in the feed, affects the muscle growth regulation in early trout growth and development. The results complement the literature data on features of the regulation of myogenesis in response to external factors.

Abstract

Skeletal muscle is highly susceptible to hypobaric hypoxia linked muscle protein loss due to disturbed proteostasis and redox homeostasis. Carnosine, an endogenous dipeptide possesses antioxidant, anti-inflammatory, anti-glycation and pH buffering properties. The present study investigated the beneficial efficacy of carnosine in amelioration of muscle protein loss during chronic hypobaric hypoxia exposure in rats. Further, probable molecular mechanism for it's protective efficacy was also established via molecular docking study along with support of in-vivo study. Male Sprague-Dawley rats were divided into three groups: Control (unexposed rats), HH (07d hypobaric hypoxia exposed rats), HH + CAR (Carnosine supplement rats with 07d hypobaric hypoxia exposure 50 mg/kg supplemented). Carnosine administration downregulated myostatin expression levels while IGF-1 level was upregulated and this was accompanied with an increase in total protein content. The expression levels of FOXO, MAFbx, MuRF1, markers of muscle atrophy were also declined on carnosine supplementation. Further, myogenesis markers, myoG, and mTOR were found increased in carnosine supplemented rats. Along with these activities, carnosine also managed excessive reactive oxygen species (ROS) production, protein oxidation and damage. Ergo, molecular docking study supported the fact that carnosine has the ability to bind with IGFBP and myostatin, a negative regulator of muscle atrophy. Carnosine attenuates muscle protein loss via enhancing myogenesis, managing redox, and protein homeostasis. All these activities together enhances protein concentration and ameliorates hypobaric hypoxia induced muscle protein loss. Therefore, carnosine supplementation can be an effective therapeutic strategy in combating skeletal muscle protein loss linked with high altitude induced hypobaric hypoxia.

Abstract

Insulin resistance develops when skeletal muscle (SM), adipose tissue (AT), and the liver fail to respond adequately to insulin, a dysfunction closely intertwined with chronic low-grade inflammation. This combination leads to compensatory hyperinsulinemia, dysglycemia, and metabolic stress, driving major disorders such as type 2 diabetes, metabolic syndrome, metabolic dysfunction-associated steatotic liver disease (MASLD), and cardiovascular disease. Both adipokines and myokines are central modulators of this metabolic-inflammatory axis. In obesity, diabetes, MASLD, and thyroid dysfunction, alterations in myokines such as myostatin, irisin, fibroblast growth factor 21 (FGF-21), apelin, brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and interleukin-15 (IL-15) influence glucose uptake, lipid oxidation, mitochondrial function, and systemic inflammation. Exercise-induced myokines exert insulin-sensitizing and anti-inflammatory effects, whereas myostatin and tumor necrosis factor-alpha (TNF-α) promote metabolic impairment. These pathways reveal extensive crosstalk between SM and key metabolic organs-including the liver, pancreas, AT, intestine, heart, and thyroid gland. In metabolic disease, inflammation-driven changes in deiodinase activity and triiodothyronine (T3) availability further link muscle dysfunction with thyroid imbalance. The aim of this narrative review was to elucidate the complex interplay between myokines, adipokines, inflammation, and insulin resistance, and to clarify their clinical relevance in metabolic and thyroid disorders. Given this integrative role of SM, sarcopenia should be recognized as a clinical marker of metabolic or thyroid dysregulation, and preserving muscle mass through structured physical activity should be a core therapeutic target.

Abstract

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert cardiometabolic benefits beyond weight loss, yet their systemic proteomic mechanisms remain incompletely defined. We profiled short-term liraglutide-induced protein changes and compared them with published semaglutide signatures.

Abstract

Denosumab, a monoclonal antibody targeting RANKL, is widely used for the treatment of osteoporosis. In addition to its skeletal benefits, emerging evidence suggests that denosumab may also exert positive effects on muscle health by modulating inflammation, myostatin expression, and insulin sensitivity through the RANK/RANKL/OPG pathway.

Abstract

Although peptide-based delivery strategies show promise for muscle and heart diseases, delivery of biotherapeutics to both skeletal and cardiac muscles remains challenging. Here, we identified a muscle-homing peptide (BV2) against blood vessel epicardial substance (BVES) by phage display. BV2 shows high binding affinity to BVES and is internalized primarily via caveolae-mediated endocytosis. Importantly, BV2 enables efficient delivery of Duchenne Muscular Dystrophy (DMD) phosphorodiamidate morpholino oligomer (PMO), mCherry protein and exosomes to skeletal muscle and heart in vivo. BV2-mCherry protein and BV2-E31R anti-myostatin peptide were effectively delivered to muscle layers when microneedles loaded with these biotherapeutics were implanted on hindlimbs of mice. Muscle mass and myofiber size also significantly increased in muscle atrophy mice grafted with BV2-E31R microneedles. Moreover, significantly enhanced restoration of dystrophin protein was achieved in peripheral and cardiac muscles of dystrophin-deficient mdx and dystrophin/utrophin double-knockout mice when exosomes simultaneously modified with BV2 and PMO. These findings highlight the potency of BV2 in directing targeted delivery of diverse biotherapeutics to muscle and heart, thus providing an effective tool for DMD and other muscular and cardiac disorders.

Abstract

Skeletal muscle is a dynamic tissue involved not only in mechanical functions but also in the regulation of metabolic and immune processes. It secretes signaling molecules known as myokines, which act in autocrine, paracrine, and endocrine ways- affecting both muscle function and other tissues and organs. Well-known myokines include myostatin, IL-6, IL-15, FGF21, and irisin. They regulate muscle mass and strength, promote angiogenesis, maintain glucose and lipid homeostasis, and contribute to immune and anti-cancer responses. Their activity depends on physiological and pathological conditions at both local and systemic levels. Notably, myokine secretion varies with muscle fiber type, influencing their specific biological effects. Understanding how myokines are regulated and function may support the development of new therapies in regenerative medicine, oncology, and metabolic disease treatment.

Abstract

This review summarizes recent advances in ligand trap therapies targeting activin type II receptors [ActRIIA/ACVR2A and ActRIIB/ACVR2B], which serve as shared receptors for members of the TGF-β family, including activins, GDF11, and myostatin [MSTN]. These receptors mediate Smad2/3 signaling and play critical roles in hematopoiesis, vascular homeostasis, and muscle regulation. Two peptide-based ligand traps have recently received clinical approval: luspatercept [ActRIIB-Fc], an erythroid maturation agent, and sotatercept [ActRIIA-Fc], a novel therapeutic agent for pulmonary arterial hypertension [PAH]. Luspatercept primarily inhibits activin B and GDF11, thereby promoting late-stage erythropoiesis and demonstrating efficacy in anemia associated with conditions such as myelodysplastic syndromes [MDS] and β-thalassemia. Sotatercept binds activins and GDFs to rebalance Smad2/3 and Smad1/5/8 signaling, thereby improving vascular remodeling in PAH. Although both agents have failed to increase skeletal muscle mass in clinical trials consistently, they represent significant advances in the treatment of hematopoietic and vascular disorders. Future studies should focus on optimal dosing strategies, long-term safety, and potential synergistic effects when combined with other therapeutic modalities.

Abstract

Sarcopenia is a prevalent and debilitating skeletal muscle disorder in the aging population, characterized by progressive loss of muscle mass, strength, and function. Despite its significant impact on mobility, independence, and healthcare systems worldwide, effective pharmacological treatments remain limited. Recent advances in the understanding of sarcopenia pathophysiology have identified myostatin-a potent negative regulator of muscle growth-as a promising therapeutic target. Myostatin inhibitors-comprising direct agents such as monoclonal antibodies and small molecules, as well as indirect modulators including follistatin-based strategies and other pathway regulators-have demonstrated encouraging results in preclinical and early clinical studies by increasing muscle mass and improving muscle function. This comprehensive review summarizes current knowledge of myostatin's molecular mechanisms in muscle homeostasis, evaluates the efficacy and safety of various myostatin-targeted therapies in sarcopenia, and discusses the translational challenges and future directions for clinical application. The integration of myostatin inhibition into therapeutic regimens offers the potential to address a critical unmet need in sarcopenia management and improve the quality of life for elderly individuals.

Abstract

Small interfering RNAs (siRNAs) hold promise for treating cardiac and muscular diseases, but robust and scalable delivery remains a hurdle. While biologic-siRNA conjugates (e.g. antibodies) are in clinical development, their manufacturing is complex. Lipophilic siRNAs are readily chemically synthesized at scale and support effective heart and muscle delivery. Here, we refine siRNA chemical design for enhanced potency and durability to support clinically relevant silencing. Targeting myostatin (MSTN), a key gene in muscle-wasting, a single subcutaneous dose in mice achieved potent silencing (80% inhibition up to 6 weeks, 30% up to 14 weeks). Biweekly dosing led to over 95% MSTN reduction for half-a-year with no observed toxicity. This resulted in muscle growth, increased lean mass, and improved grip strength. Phenotypical benefits extended beyond direct target silencing, suggesting prolonged effects. The siRNA scaffold was effective across multiple muscle groups, with its modularity confirmed by three additional targets. Optimized dosing extended durability to 20 weeks without compromising phenotypic outcomes. As a proof of concept, MSTN inhibition with siRNAs successfully combated muscle wasting in an inflammatory myopathy model (cardiotoxin). These findings pave the way for long-lasting gene modulation in heart and muscle, offering new therapeutic strategies for muscular diseases.

Abstract

Glucagon-like peptide-1 (GLP-1) analogs, originally developed as antidiabetic agents, have emerged as groundbreaking drugs for treating obesity, following reports of their remarkable weight-reducing effects. With growing recognition of obesity as a disease in modern society and a sharp rise in its prevalence, pharmacological interventions are now being actively pursued. However, due to their mechanism of action, primarily appetite suppression, GLP-1 analogs have been associated with various adverse effects. Most notably, muscle loss - which may be related to reduced nutritional intake - has become an important issue in the long-term management of patients undergoing GLP-1 therapy. This has drawn attention to myostatin (MSTN) inhibitors for their ability to significantly increase muscle mass. These agents are now being explored not only as a strategy to offset the side effects of GLP-1 analogs, but also as direct therapeutics for a range of metabolic disorders, including obesity and diabetes. In this review, we discuss the emerging therapeutic potential of MSTN inhibitors and examine current clinical trials investigating their use alone or in combination with GLP-1 analogs in metabolic disorders.

Abstract

Muscle wasting disorders, including sarcopenia and skeletal muscle atrophy, are increasingly prevalent among older adults and those with metabolic comorbidities. Sarcopenia, a progressive age-associated condition, involves the decline in skeletal muscle mass, strength, and physical performance, affecting millions of people globally. These disorders significantly elevate the risks of frailty, falls, and premature mortality, contributing to a growing burden on healthcare systems. Current interventions, including resistance exercise and dietary supplementation, have shown limited effectiveness, particularly among individuals with concurrent conditions such as type 2 diabetes (T2D). Notably, glucagon-like peptide-1 receptor agonists (GLP-1RAs), initially developed for glycemic and weight control, have demonstrated promising effects in preclinical models of muscle degeneration. In this review, we analyzed 20 preclinical and clinical studies on sarcopenia and muscle wasting disorders. Animal studies yielded promising results, including increased grip strength and enhanced skeletal muscle cross-sectional area (CSA), while body weight remained stable within a defined dosage range. Mechanistically, GLP-1RAs mitigate muscle wasting by upregulating myogenic factors (MyoD, MyoG), promoting mitochondrial biogenesis, and suppressing proteolysis (MuRF1, MAFbx) and inflammation via AMPK/SIRT1/NF-κB/Myostatin signaling. In contrast, limited clinical studies showed body weight reduction accompanied by a decline in lean mass following GLP-1RA treatment. Collectively, these results highlight the low dose-dependent anabolic potential of GLP-1RAs on skeletal muscle, while clinical evidence indicates simultaneous weight and lean mass loss. These findings suggest low-dose GLP-1RAs as potential therapy for sarcopenic obesity or early sarcopenia with metabolic comorbidities, warranting comprehensive clinical trials that incorporate multimodal strategies to preserve muscle mass during treatment.

Abstract

The MSTN-mutated cattle exhibit an enhancement in meat production while maintaining health. However, the study on meat quality of MSTN-mutated beef is still limited. Herein, we firstly investigated the pH values in different muscle tissues from wild-type (WT) and MSTN mutant-type (MT) Mongolian cattle during post-mortem period and found that all MT beef reached ultimate pH (upH) earlier than WT. Furthermore, shear force, pressing loss, cooking loss, total histone crotonylation level and histone H3 lysine 18 crotonylation (H3K18cr) level were increased in longissimus dorsi, tenderloin, sirloin and brisket muscles of MT cattle. Mechanism studied demonstrated that the expression levels of glycolysis-related genes accompanied by enhanced H3K18cr modification at HK2 promoter were higher in MT muscles compared with that of WT. This finding provides new insights into meat aging process in MSTN-mutated cattle, thereby facilitating the rapid development of the beef industry.

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic condition with a complex pathophysiology involving multiple organs. Organokines, including hepatokines, myokines, cardiokines, renokines, osteokines, and adipokines, play central roles in lipid metabolism, glucose homeostasis, inflammation, and fibrosis. Dysregulation of these signaling molecules contributes to the progression of MASLD and its systemic complications. This review examines the role of organokine-mediated crosstalk between the liver and peripheral organs (e.g., muscle, heart, kidneys, bone, and adipose tissue) in the pathogenesis of MASLD. Key molecules, such as myostatin, FGF-21, IL-6, and adiponectin, influence insulin sensitivity, lipid metabolism, and inflammation. Some organokines have protective effects (e.g., FGF-21, irisin, and klotho), while others, such as myostatin and fetuin-A, exacerbate insulin resistance and fibrosis. These findings suggest that targeting organokines could provide potential biomarkers and therapeutic strategies for MASLD. Future research should focus on elucidating the molecular mechanisms and assessing the role of organokines in the prevention and treatment of MASLD.

Abstract

This study investigated whether fermented mealworms extract (FME) can simultaneously improve postmenopausal osteoporosis and muscle atrophy, along with the underlying mechanisms. Female C57BL/6 N mice were divided into five groups: sham-operated, ovariectomized (OVX), OVX treated with two doses of FME (200 and 500 mg/kg, oral), and OVX treated with alendronate (Alen, 500 μg/kg, oral) as a positive control, for 15 weeks. FME500 significantly increased grip strength, whereas FME200 showed no significant improvement compared to the OVX group. Muscle cross-sectional area significantly increased in both FME groups compared to the OVX group. FME500 also enhanced muscle protein synthesis markers (MyoD1 and MHC) and more effectively suppressed muscle degradation markers (MuRF-1, atrogin-1, myostatin, and polyubiquitinated proteins) than FME200. In bone, both FME doses improved bone density and serum levels of RANKL and CTX-1 compared to the OVX group. FME500 more effectively downregulated RANKL, IL-6, and TNF-α expression in both bone and muscle than FME200 in OVX group. Mechanistic analyses were performed mainly in the FME500 group, which downregulated NFκB/MAPK and upregulated IGF-1-PI3K-Akt in both bone and muscle. These results indicate that FME suppresses the postmenopausal concurrent bone and muscle loss by regulating RANKL-NFκB/MAPK and IGF-1-PI3K-Akt signaling pathways.

Abstract

CRISPR-Cas9 genome editing offers significant opportunities to improve livestock traits; however, its application in buffalo has been very limited, with no prior reports of live gene-edited animals. Here, we report the successful birth of a buffalo edited in the myostatin (MSTN) gene. To achieve this, five single-guide RNAs (sgRNAs) targeting the buffalo MSTN gene were designed and tested in skin-derived fibroblasts. Among these, sgRNA5 exhibited the highest editing efficiency, approaching ∼50%, as confirmed by T7 Endonuclease I assay, Tracking of Indels by Decomposition, and Inference of CRISPR Edits analyses. Single-cell cloning identified six edited fibroblast clonal populations, including one with a bi-allelic frameshift mutation predicted to severely truncate the MSTN protein. These bi-allelic clonal cells were subsequently used as nuclear donors to produce somatic cell nuclear transfer (SCNT) embryos, which were transferred into recipient buffaloes (n = 15). This effort established three pregnancies and resulted in the birth of one live MSTN knockout buffalo calf. Phenotypically, the calf displayed accelerated growth and increased muscle fiber number and size while maintaining normal meat composition. In conclusion, this study reports the world's first gene-edited buffalo generated through CRISPR-Cas9-mediated genome editing combined with SCNT. These findings provide a proof-of-concept for genome editing in buffalo and demonstrate that MSTN disruption can effectively enhance muscle growth and meat production traits.

Abstract

Myostatin and follistatin are the regulators of muscle growth and pivotal proteins that regulate muscle tissue function. An integrated approach is HIIT and resistance training provides a holistic strategy for promoting healthy aging and maintaining functional abilities, potentially through the modulation of myostatin and follistatin levels. This study aims to assess the effect of high-intensity interval training and resistance training on myostatin and follistatin protein concentrations in aged rats' serum and muscle tissue. In this study, 20-month-old female Sprague-Dawley rats were used in three groups: (1) Control (Con), (2) Resistance training (RT), and (3) High-intensity interval training (HIIT). The HIIT and resistance training protocols were carried out for 8 weeks and three sessions per week. The results showed serum levels and muscle tissue content of myostatin increased in the RT compared to the control group (p = 0.0001 and p = 0.04). The muscle tissue content of follistatin increased in the HIIT compared to the control group (p = 0.03). There is a significant difference in serum levels and muscle tissue content of follistatin between HIIT and RT groups (p = 0.0001 and p = 0.001). According to the roles of myostatin and follistatin in regulating muscle hypertrophy, present research shows HIIT has more effects on follistatin levels and resistance training has more effects on myostatin levels. This can indicate that according to the number of training sessions, HIIT can be a better and newer treatment method for older people.

Abstract

Myostatin (M), activin-A (A) and follistatin (F), three TGF-β superfamily members, play a role in cancer sarcopenia. The aim of our study was to assess the association of MAF in head and neck cancer (HNC) skeletal muscle loss.

Abstract

Myostatin (MSTN) and Callipyge (CLPG) genes are key regulators of muscle growth. While MSTN inhibits muscle development, the CLPG mutation induces muscle hypertrophy through a specific imprinted genetic mechanism. The interaction between these genes remains of interest for improving livestock muscle traits. In this study, CRISPR/Cas9 was employed to edit MSTN and CLPG genes in goat fibroblast cells via electrotransfection. Cells were selected using puromycin antibiotic, and gene-editing efficiency was evaluated through Sanger sequencing. Gene expression changes were analyzed using RT-qPCR analysis. MSTN gene knockout resulted in significant downregulation of MSTN and CLPG, while GTL2 expression was upregulated by more than 50-fold. Additionally, myosin heavy chain genes (MYH1, MYH3, MYH4) were strongly upregulated, with MYH3 13-fold and MYH4 30-fold increase in the expression. In CLPG-edited cells, the expression of MSTN, TRIM28, and CLPG was reduced, while GTL2 was upregulated by 6-fold. MYH3 and MYH4 expression increased 4-fold in CLPG-edited cells, though the increase was less pronounced compared to MSTN-edited cells. DLK1 expression was undetectable in both non-edited control and gene-edited fibroblast cells. Our findings support the interaction between MSTN and CLPG, contributing to the regulation of muscle growth. Notably, the study also highlights the challenges associated with editing imprinted genes like CLPG and suggests that TRIM28 may play a role downstream of CLPG regulation. These results provide valuable insights into muscle development regulation, offering potential applications in livestock genetic improvement.