Computational Identification of Dithymoquinone as a Potential Inhibitor of Myostatin and Regulator of Muscle Mass

Mss51 protein inhibition serves as a novel target for type 2 diabetes: a molecular docking and simulation study

Myostatin is a widely recognized inhibitory factor of skeletal muscle growth and significantly influences muscle development and metabolism. In mice, myostatin inhibition improves insulin sensitivity, increases glucose uptake by skeletal muscle, and reduces body fat. Furthermore, Mss51 is downregulated in response to myostatin inhibition, and its deletion appears to improve the metabolic state of skeletal muscle and reduce adipose tissue, which makes Mss51 a potential target for the treatment of obesity and type 2 diabetes. Here, we report a computationally predicted and validated three-dimensional structure of Mss51. Computational screening was used to identify naturally occurring compounds from the Herbal and Specs chemical database that might inhibit Mss51, based on binding affinities and physiochemical and ADMET properties. ZINC00338371, ZINC95099599 and ZINC08214878 were found to bind to Mss51 with high binding affinity and specificity. In addition, 100 ns molecular dynamics simulations were conducted to assess the stabilities of the interactions between the three compounds and Mss51. MD simulation demonstrated that all three compounds bind to the active pocket site of Mss51 stably and cause conformation changes. ZINC00338371 was found to bind most stably with binding free energy -229.022 ± 13.776 kJ/mol to Mss51, suggesting that it has therapeutic potential as a treatment option for obesity and type 2 diabetes.Communicated by Ramaswamy H. Sarma.

Therapeutic applications of biological macromolecules and scaffolds for skeletal muscle regeneration: A review

Skeletal muscle (SM) mass and strength maintenance are important requirements for human well-being. SM regeneration to repair minor injuries depends upon the myogenic activities of muscle satellite (stem) cells. However, losses of regenerative properties following volumetric muscle loss or severe trauma or due to congenital muscular abnormalities are not self-restorable, and thus, these conditions have major healthcare implications and pose clinical challenges. In this context, tissue engineering based on different types of biomaterials and scaffolds provides an encouraging means of structural and functional SM reconstruction. In particular, biomimetic (able to transmit biological signals) and several porous scaffolds are rapidly evolving. Several biological macromolecules/biomaterials (collagen, gelatin, alginate, chitosan, and fibrin etc.) are being widely used for SM regeneration. However, available alternatives for SM regeneration must be redesigned to make them more user-friendly and economically feasible with longer shelf lives. This review aimed to explore the biological aspects of SM regeneration and the roles played by several biological macromolecules and scaffolds in SM regeneration in cases of volumetric muscle loss.

Licochalcone A and B enhance muscle proliferation and differentiation by regulating Myostatin

BACKGROUND

Myostatin (MSTN) inhibition has demonstrated promise for the treatment of diseases associated with muscle loss. In a previous study, we discovered that Glycyrrhiza uralensis (G. uralensis) crude water extract (CWE) inhibits MSTN expression while promoting myogenesis. Furthermore, three specific compounds of G. uralensis, namely liquiritigenin, tetrahydroxymethoxychalcone, and Licochalcone B (Lic B), were found to promote myoblast proliferation and differentiation, as well as accelerate the regeneration of injured muscle tissue.

PURPOSE

The purpose of this study was to build on our previous findings on G. uralensis and demonstrate the potential of its two components, Licochalcone A (Lic A) and Lic B, in muscle mass regulation (by inhibiting MSTN), aging and muscle formation.

METHODS

G. uralensis, Lic A, and Lic B were evaluated thoroughly using in silico, in vitro and in vivo approaches. In silico analyses included molecular docking, and dynamics simulations of these compounds with MSTN. Protein-protein docking was carried out for MSTN, as well as for the docked complex of MSTN-Lic with its receptor, activin type IIB receptor (ACVRIIB). Subsequent in vitro studies used C2C12 cell lines and primary mouse muscle stem cells to acess the cell proliferation and differentiation of normal and aged cells, levels of MSTN, Atrogin 1, and MuRF1, and plasma MSTN concentrations, employing techniques such as western blotting, immunohistochemistry, immunocytochemistry, cell proliferation and differentiation assays, and real-time RT-PCR. Furthermore, in vivo experiments using mouse models focused on measuring muscle fiber diameters.

RESULTS

CWE of G. uralensis and two of its components, namely Lic A and B, promote myoblast proliferation and differentiation by inhibiting MSTN and reducing Atrogin1 and MuRF1 expressions and MSTN protein concentration in serum. In silico interaction analysis revealed that Lic A (binding energy -6.9 Kcal/mol) and B (binding energy -5.9 Kcal/mol) bind to MSTN and reduce binding between it and ACVRIIB, thereby inhibiting downstream signaling. The experimental analysis, which involved both in vitro and in vivo studies, demonstrated that the levels of MSTN, Atrogin 1, and MuRF1 were decreased when G. uralensis CWE, Lic A, or Lic B were administered into mice or treated in the mouse primary muscle satellite cells (MSCs) and C2C12 myoblasts. The diameters of muscle fibers increased in orally treated mice, and the differentiation and proliferation of C2C12 cells were enhanced. G. uralensis CWE, Lic A, and Lic B also promoted cell proliferation in aged cells, suggesting that they may have anti-muslce aging properties. They also reduced the expression and phosphorylation of SMAD2 and SMAD3 (MSTN downstream effectors), adding to the evidence that MSTN is inhibited.

CONCLUSION

These findings suggest that CWE and its active constituents Lic A and Lic B have anti-mauscle aging potential. They also have the potential to be used as natural inhibitors of MSTN and as therapeutic options for disorders associated with muscle atrophy.

Current situation and publication trends of skeletal muscle related research: A bibliometric analysis

Skeletal muscle (SM) is a highly plastic and dynamic tissue of the body and is largely responsible for body maintenance. SM is primarily responsible for body balance, movement, postural support, thermogenesis, and blood glucose homeostasis. SM regeneration depends on the activation of muscle satellite (stem) cells (MSCs) under the regulation of several muscle regulatory factors that regulate myogenesis. Bibliometric analysis involves the quantitative and qualitative assessments of research and scientific progress that provides researchers access to recent publications, research directions, and thus generates ideas that can be implemented to guide future research. In this analysis, the Web of Science database was searched for articles using the search term "skeletal muscle AND myogenesis AND muscle satellite cell", and 1777 articles (original research/review articles) published from the year 1997 to June 2023 were retrieved. After applying several other exclusion and inclusion criteria, 129 articles were considered for analysis. Types of research, keywords, journals, authors, years, institutions, funding agencies, and average annual citations were analyzed. Muscle regeneration, satellite cell, and myogenesis were often used keywords and exhibited increasing trends in research articles over the decades. Some journals were found to strongly support research publications with high impact factors and citation scores. This study aimed to examine research ideas and growth in the skeletal muscle related field for atrophy and aging improvement.

Targeting myostatin using quercetin as a media supplement to improve myogenesis for cultured meat production: An in silico and in vitro study

Cultured meat (CM) is an alternative protein food and is produced by cultivating muscle satellite (stem) cells (MSCs) derived from livestock animals (bovine, chickens, and porcine) through myogenesis leading to generate muscle mass. Myostatin (MSTN) is well well-known negative regulator of myogenesis, and in the present study, in silico screening of natural compounds was performed to identify MSTN inhibitors. Interestingly, quercetin was found to inhibit MSTN (binding energy -7.40 kcal/mol), and this was further validated by a 100 ns molecular dynamics simulation. Quercetin was added to culture media to boost myogenesis, and its potent antioxidant property helped maintain media pH. Furthermore, quercetin increased the myotube thickness and length, increased MSC differentiation, and upregulated the gene and protein expressions of myoblast determination protein 1 (MYOD), Myogenin (MYOG), and Myosin heavy chains (MYH) in vitro. In addition, quercetin inhibited the activities of MSTN, activin receptor type-2B (ACVR2B), and SMAD2 and 3, and thus significantly enhanced MSC differentiation and myotube formation. Overall, this study shows that quercetin might be useful for enhancing large-scale CM production. It is hoped that this study provides a starting point for research in the CM area aimed to enhancing product quality, nutritional values, and the efficacy of large-scale production.

Therapeutic applications of ginseng for skeletal muscle-related disorder management

Skeletal muscle (SM) is the largest organ of the body and is largely responsible for the metabolism required to maintain body functions. Furthermore, the maintenance of SM is dependent on the activation of muscle satellite (stem) cells (MSCs) and the subsequent proliferation and fusion of differentiating myoblasts into mature myofibers (myogenesis). Natural compounds are being used as therapeutic options to promote SM regeneration during aging, muscle atrophy, sarcopenia, cachexia, or obesity. In particular, ginseng-derived compounds have been utilized in these contexts, though ginsenoside Rg1 is mostly used for SM mass management. These compounds primarily function by activating the Akt/mTOR signaling pathway, upregulating myogenin and MyoD to induce muscle hypertrophy, downregulating atrophic factors (atrogin1, muscle ring-finger protein-1, myostatin, and mitochondrial reactive oxygen species production), and suppressing the expressions of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in cachexia. Ginsenoside compounds are also used for obesity management, and their anti-obesity effects are attributed to peroxisome proliferator activated receptor gamma (PPARγ) inhibition, AMPK activation, glucose transporter type 4 (GLUT4) translocation, and increased phosphorylations of insulin resistance (IR), insulin receptor substrate-1 (IRS-1), and Akt. This review was undertaken to provide an overview of the use of ginseng-related compounds for the management of SM-related disorders.

Identification of active compounds as novel dipeptidyl peptidase-4 inhibitors through machine learning and structure-based molecular docking simulations

The enzyme dipeptidyl peptidase 4 (DPP4) is a potential therapeutic target for type 2 diabetes (T2DM). Many synthetic anti-DPP4 medications are available to treat T2DM. The need for secure and efficient medicines has been unmet due to the adverse side effects of existing DPP4 medications. The present study implemented a combined approach to machine learning and structure-based virtual screening to identify DPP4 inhibitors. Two ML models were trained based on DPP4 IC50 datasets. The ML models random forest (RF) and multilayer perceptron (MLP) neural network showed good accuracy, with the area under the curve being 0.93 and 0.91, respectively. The natural compound library was screened through ML models, and 1% (217) of compounds were selected for further screening. Structure-based virtual screening was performed along with positive control sitagliptin to obtain more specific and selective leads for DPP4. Based on binding affinity, drug-likeness properties, and interaction with DPP4, Z-614 and Z-997 compounds showed high binding affinity and specificity in the catalytic pocket of DPP4. Finally, the stability conformation of the DPP4 enzyme complex was checked by a molecular dynamics (MD) simulation. The MD simulation showed that both compounds bind better in the catalytic pocket, but the Z-614 compound altered the DPP4 native conformation. Therefore, Z-614 showed a high deviation in the backbone. This combined approach (ML and structure-based) study reported that Z-997 binds most stably to DPP4 in their catalytic pocket with a binding free energy of -70.3 kJ/mol, suggesting its therapeutic potential as a treatment option for T2DM disease.Communicated by Ramaswamy H. Sarma.

Therapeutic Applications of Ginseng Natural Compounds for Health Management

Ginseng is usually consumed as a daily food supplement to improve health and has been shown to benefit skeletal muscle, improve glucose metabolism, and ameliorate muscle-wasting conditions, cardiovascular diseases, stroke, and the effects of aging and cancers. Ginseng has also been reported to help maintain bone strength and liver (digestion, metabolism, detoxification, and protein synthesis) and kidney functions. In addition, ginseng is often used to treat age-associated neurodegenerative disorders, and ginseng and ginseng-derived natural products are popular natural remedies for diseases such as diabetes, obesity, oxidative stress, and inflammation, as well as fungal, bacterial, and viral infections. Ginseng is a well-known herbal medication, known to alleviate the actions of several cytokines. The article concludes with future directions and significant application of ginseng compounds for researchers in understanding the promising role of ginseng in the treatment of several diseases. Overall, this study was undertaken to highlight the broad-spectrum therapeutic applications of ginseng compounds for health management.

Age Is Just a Number: Progress and Obstacles in the Discovery of New Candidate Drugs for Sarcopenia

Sarcopenia is a disease characterized by the progressive loss of skeletal muscle mass and function that occurs with aging. The progression of sarcopenia is correlated with the onset of physical disability, the inability to live independently, and increased mortality. Due to global increases in lifespan and demographic aging in developed countries, sarcopenia has become a major socioeconomic burden. Clinical therapies for sarcopenia are based on physical therapy and nutritional support, although these may suffer from low adherence and variable outcomes. There are currently no clinically approved drugs for sarcopenia. Consequently, there is a large amount of pre-clinical research focusing on discovering new candidate drugs and novel targets. In this review, recent progress in this research will be discussed, along with the challenges that may preclude successful translational research in the clinic. The types of drugs examined include mitochondria-targeting compounds, anti-diabetes agents, small molecules that target non-coding RNAs, protein therapeutics, natural products, and repositioning candidates. In light of the large number of drugs and targets being reported, it can be envisioned that clinically approved pharmaceuticals to prevent the progression or even mitigate sarcopenia may be within reach.

Fiber-Type Shifting in Sarcopenia of Old Age: Proteomic Profiling of the Contractile Apparatus of Skeletal Muscles

The progressive loss of skeletal muscle mass and concomitant reduction in contractile strength plays a central role in frailty syndrome. Age-related neuronal impairments are closely associated with sarcopenia in the elderly, which is characterized by severe muscular atrophy that can considerably lessen the overall quality of life at old age. Mass-spectrometry-based proteomic surveys of senescent human skeletal muscles, as well as animal models of sarcopenia, have decisively improved our understanding of the molecular and cellular consequences of muscular atrophy and associated fiber-type shifting during aging. This review outlines the mass spectrometric identification of proteome-wide changes in atrophying skeletal muscles, with a focus on contractile proteins as potential markers of changes in fiber-type distribution patterns. The observed trend of fast-to-slow transitions in individual human skeletal muscles during the aging process is most likely linked to a preferential susceptibility of fast-twitching muscle fibers to muscular atrophy. Studies with senescent animal models, including mostly aged rodent skeletal muscles, have confirmed fiber-type shifting. The proteomic analysis of fast versus slow isoforms of key contractile proteins, such as myosin heavy chains, myosin light chains, actins, troponins and tropomyosins, suggests them as suitable bioanalytical tools of fiber-type transitions during aging.

Molecular Mechanisms and Current Treatment Options for Cancer Cachexia

Simple Summary

The primary characteristics of cancer cachexia are weakness, weight loss, atrophy, fat reduction, and systemic inflammation. Cachexia is strongly associated with cancers involving the lungs, pancreas, esophagus, stomach, and liver, which account for half of all cancer deaths. TGF-β, MSTN, activin, IGF-1/PI3K/AKT, and JAK-STAT signaling pathways are known to underlie muscle atrophy and cachexia. Anamorelin (appetite stimulation), megestrol acetate, eicosapentaenoic acid, phytocannabinoids, targeting MSTN/activin, and molecules targeting proinflammatory cytokines, such as TNF-α and IL-6, are being tested as treatment options for cancer cachexia.

Abstract

Cancer cachexia is a condition marked by functional, metabolic, and immunological dysfunctions associated with skeletal muscle (SM) atrophy, adipose tissue loss, fat reduction, systemic inflammation, and anorexia. Generally, the condition is caused by a variety of mediators produced by cancer cells and cells in tumor microenvironments. Myostatin and activin signaling, IGF-1/PI3K/AKT signaling, and JAK-STAT signaling are known to play roles in cachexia, and thus, these pathways are considered potential therapeutic targets. This review discusses the current state of knowledge of the molecular mechanisms underlying cachexia and the available therapeutic options and was undertaken to increase understanding of the various factors/pathways/mediators involved and to identify potential treatment options.