Psoralea corylifolia L. seed extract attenuates dexamethasone-induced muscle atrophy in mice by inhibition of oxidative stress and inflammation

Plant-Derived Treatments for Different Types of Muscle Atrophy

With the development of medicine and chemistry, an increasing number of plant-derived medicines have been shown to exert beneficial therapeutic on the treatment of various physical and psychological diseases. In particular, by using physical chemistry methods, we are able to examine the chemical components of plants and the effects of these substances on the human body. Muscle atrophy (MA) is characterized by decreased muscle mass and function, is caused by multiple factors and severely affects the quality of life of patients. The multifactorial and complex pathogenesis of MA hinders drug research and disease treatment. However, phytotherapy has achieved significant results in the treatment of MA. We searched PubMed and the Web of Science for articles related to plant-derived substances and muscle atrophy. After applying exclusion and inclusion criteria, 166 and 79 articles met the inclusion criteria, respectively. A total of 173 articles were included in the study after excluding duplicates. The important role of phytoactives such as curcumin, resveratrol, and ginsenosides in the treatment of MA (e.g., maintaining a positive nitrogen balance in muscles and exerting anti-inflammatory and antioxidant effects) has been extensively studied. Unfortunately, MA dose not have to a single cause, and each cause has its own unique mechanism of injury. This review focuses on the therapeutic mechanisms of active plant components in MA and provides insights into the personalized treatment of MA.

Utilizing zebrafish models to elucidate mechanisms and develop therapies for skeletal muscle atrophy

Skeletal muscle atrophy, resulting from an imbalance in muscle protein synthesis and degradation, compromises muscle quality and function, imposing significant burdens on movement and metabolic stability. Animal models are crucial for understanding the mechanisms of skeletal muscle atrophy and developing clinical prevention and treatment strategies. Zebrafish, as small aquatic vertebrates, exhibit high genetic homology with humans and offer advantages such as rapid reproduction, development, and transparent embryos. Their physiological and anatomical similarities to mammals, including a substantial proportion of skeletal muscle and observable swimming behavior reflecting body dysfunction, make zebrafish an ideal model for studying skeletal muscle-related diseases. This review outlines the development of zebrafish skeletal muscle and highlights key pathways regulating muscle proteins, emphasizing their anatomical and genetic consistency with humans. Various zebrafish models of skeletal muscle atrophy created through physical, chemical, and gene-editing methods are systematically summarized. Current challenges and proposed improvement strategies are also discussed to enhance the reliability and applicability of zebrafish models, providing a comprehensive reference for advancing research on skeletal muscle atrophy.

Standardized Boesenbergia pandurata Extract Prevents Dexamethasone-Induced Muscle Atrophy and Dysfunction in C57BL/6 Mice

Muscle atrophy, characterized by diminished muscle mass and impaired function, poses a substantial global health concern. Boesenbergia pandurata (Roxb.) Schltr., commonly known as fingerroot, possesses a variety of advantageous activities, including anti-inflammatory, antioxidant, antibacterial, and anticancer effects. However, there are currently no preclinical studies available that explore the potential of B. pandurata extract (BPE) to mitigate muscle atrophy. In this study, we aimed to explore the protective effects of BPE, standardized to panduratin A content, against muscle atrophy and its underlying molecular mechanisms in a dexamethasone-induced muscle atrophy mouse model. Compared with the dexamethasone group, BPE significantly restored muscle mass, muscle volume, muscle fiber cross-sectional area, grip strength, and exercise endurance. Additionally, BPE suppressed inflammatory responses by downregulating the expressions of nuclear factor kappa B and inflammatory cytokines while also enhancing antioxidant effects by increasing the expressions of antioxidant enzymes. Moreover, BPE promoted protein synthesis and muscle differentiation by stimulating the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling pathway. Furthermore, it suppressed myostatin expression and inhibited the expressions of E3 ubiquitin ligases by preventing the nuclear translocation of forkhead box O3a, thereby alleviating proteolysis. Overall, BPE effectively regulates unbalanced protein metabolism, suggesting its potential as a functional food ingredient for preventing muscle wasting diseases.

Effects of Alnus japonica Hot Water Extract and Oregonin on Muscle Loss and Muscle Atrophy in C2C12 Murine Skeletal Muscle Cells

Background/Objectives: Sarcopenia is characterized by the loss of muscle mass and function, increases in mortality rate, and risk of comorbidities in the elderly. This study evaluated the effects of Alnus japonica hot water extract (AJHW) and its active compound, oregonin, on muscle atrophy and apoptosis in vitro. Methods: AJHW underwent phytochemical analysis. C2C12 cells were subjected to H2O2 and dexamethasone to induce oxidative stress and muscle loss, after which AJHW and oregonin were administered to assess their impacts on cell viability, apoptosis, muscle protein synthesis stimulation, and muscle protein degradation inhibition. Cell viability was assessed via an MTT assay, and apoptosis was analyzed by measuring Bcl-2, Bax, cleaved caspase-3, and cleaved PARP through Western blotting. Western blotting and RT-PCR were utilized to analyze MyoD, Myogenin, Atrogin-1, and MuRF1 protein and gene expression in a muscle atrophy model, as well as the Akt/mTOR and FoxO3α pathways. Results: AJHW was confirmed to contain oregonin, an active compound. AJHW and oregonin significantly increased cell viability and reduced apoptosis by upregulating Bcl-2 and downregulating Bax, cleaved caspase-3, and cleaved PARP. They significantly enhanced muscle protein synthesis through the upregulation of MyoD and Myogenin, while diminishing muscle degradation by downregulating Atrogin-1 and MuRF1. The activation of the Akt/mTOR pathway and inhibition of the FoxO3α pathway were also observed. Conclusions: AJHW and oregonin effectively prevented muscle cell apoptosis, promoted muscle protein synthesis, and inhibited muscle protein degradation in vitro. These results suggest that AJHW and oregonin could serve as therapeutic agents to prevent and treat sarcopenia.

Aquo-ethanolic extract of Lilii Bulbus attenuates dexamethasone-induced muscle loss and enhances muscle strength in experimental mice

Traditionally, Lilium lancifolium bulb is known for its ability to nourish yin, nourish the lungs, clear the heart, soothe coughs, reduce irritability, and calm the mind. In Oriental Medicine, it is categorized as a tonic remedy for alleviating symptoms of fatigue and enhancing the strength of bones and muscles. In this study, we aimed to validate the effectiveness of the aquo-ethanolic extract of Lilli Bulbus (LBE) in a dexamethasone (DEX)-induced muscle atrophy model, both in vitro and in vivo, and elucidate its mechanism of action through muscle transcriptome analysis. The effects of LBE on the viability and myotube density of C2C12 myoblasts and differentiated C2C12 myotubes with and without DEX treatment were investigated. LBE pretreatment protected C2C12 myoblast cells and increased the muscle density of C2C12 myotubes in response to DEX. LBE showed potent free radical scavenging activities in cell-free biochemical assays as well as antioxidant activity in C2C12 myoblasts. LBE also exhibited protective effects in an experimental animal model of DEX-induced muscle atrophy, showing muscular function and motor coordination recovery. Transcriptomic analysis of three different muscle tissues from mice with DEX-induced muscle atrophy showed that the regulation of the extracellular matrix was perturbed by glucocorticoid treatment, and this perturbation was reversed by LBE treatment. Collectively, LBE alleviated skeletal muscle loss and maintained muscle function from the chronic toxicity of DEX by protecting muscle cells from various stressful conditions, as well as DEX itself, inhibiting muscle protein degradation, and preserving the muscle tissue microenvironment.

Molecular mechanism of skeletal muscle loss and its prevention by natural resources

A skeletal muscle disorder has drawn attention due to the global aging issues. The loss of skeletal muscle mass has been suggested to be from the reduced muscle regeneration by dysfunction of muscle satellite cell/fibro-adipogenic progenitor cells and the muscle atrophy by dysfunction of mitochondria, ubiquitin-proteasome system, and autophagy. In this review, we highlighted the underlying mechanisms of skeletal muscle mass loss including Notch signaling, Wnt/β-catenin signaling, Hedgehog signaling, AMP-activated protein kinase (AMPK) signaling, and mammalian target of rapamycin (mTOR) signaling. In addition, we summarized accumulated studies of natural resources investigating their roles in ameliorating the loss of skeletal muscle mass and demonstrating the underlying mechanisms in vitro and in vivo. In conclusion, following the studies of natural resources exerting the preventive activity in muscle mass loss, the signaling-based approaches may accelerate the development of functional foods for sarcopenia prevention.

Characterizing metabolomic and transcriptomic changes, and investigating the therapeutic mechanism of Psoralea corylifolia linn. In the treatment of kidney-yang deficiency syndrome in rats

Kidney-yang deficiency syndrome (KYDS) is characterized by a metabolic disorder stemming from neuroendocrine dysregulation, often associated with hepatic dysfunction. In traditional Chinese medicine, Psoralea corylifolia Linn. (BGZ) is commonly utilized for treating KYDS. However, the specific therapeutic effects of BGZ on liver function regulation remain unclear. To evaluate the protective effects of BGZ against KYDS in rats, organ index, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and other biochemical indices were analyzed. Hematoxylin and eosin (HE) staining was utilized to assess liver histopathology. Additionally, transcriptomic and metabolomic analyses were conducted to identify potential biomarkers. BGZ treatment led to a significant reduction in ALT and AST levels, accompanied by improvements in liver histopathology in rats with KYDS. Moreover, BGZ induced significant alterations in 92 differentially expressed genes (DEGs) and 20 metabolites in the KYDS rat model. The comprehensive examination of metabolites and DEGs identified potential mechanisms underlying the therapeutic effects of BGZ, highlighting the neuroactive ligand-receptor interaction, cAMP signaling pathway, calcium signaling pathway, and cytokine-cytokine receptor interaction as key mechanisms. Validation of key targets within the cAMP pathway was substantiated through enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction. The cAMP pathway emerges as a plausible mechanism through which BGZ exerts protective effects against KYDS. The findings of this study contribute to an improved understanding of the therapeutic actions of BGZ and establish a groundwork for further research into the complex pathways involved, as well as the potential for drug-targeted therapies for KYDS.

Human umbilical cord mesenchymal stem cell-derived exosomes ameliorate muscle atrophy via the miR-132-3p/FoxO3 axis

Background

Muscle atrophy or sarcopenia is the loss of muscle mass and strength and leads to an increased risk of disability and death including osteoporotic fractures. Currently, there are no available clinical biologic agents for the treatment of sarcopenia. Since exosomes have become increasingly attractive as a novel therapeutic approach due to their ability to facilitate cell-cell transfer of proteins and RNAs, promoting cell repair and function recovery, we hypothesized that human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Exos) might benefit muscle atrophy in age-related and dexamethasone-induced sarcopenia animal models.

Methods

HucMSC-Exos were harvested by ultrafast centrifugation and identified by transmission electron microscopy, particle size analysis, and Western blot analysis. The effects of hucMSC-Exos on muscle atrophy were evaluated using age-related and dexamethasone-induced muscle atrophy mice models. Body weight, grip strength, muscle weight, and muscle histology of these mice were assessed. The expression levels of muscle RING finger 1 (MuRF1) and muscle atrophy F-box (atrogin-1) were measured by Western blot. Dexamethasone-induced C2C12 myotube atrophy was used to establish the cell model of muscle atrophy. Myotube diameter was evaluated by immunofluorescence staining. Bioinformatic analysis, RNA sequencing analysis, and Western blot analysis were performed to explore the underlying mechanisms.

Results

In vivo experiments, hucMSC-Exos demonstrated a remarkable capacity to improve grip strength, increase muscle mass, and muscle fiber cross-sectional area, while concurrently reducing the expression of MuRF1 and atrogin-1 in age-related and dexamethasone-induced muscle atrophy mice. In vitro experiments, hucMSC-Exos can promote the proliferation of C2C12 cells, and rescue the dexamethasone-induced decline in the viability of C2C12 myotubes. In addition, hucMSC-Exos can increase the diameter of C2C12 myotubes, and reduce dexamethasone-induced upregulation of MuRF1 and atrogin-1. Combined with bioinformatics analysis and RNA sequencing analysis, we further showed that miR-132-3p was one of the essential miRNAs in hucMSC-Exos and played an important role by targeting FoxO3.

Conclusion

Our findings suggested that hucMSC-Exos can improve age-related and dexamethasone-induced muscle atrophy in mice models. This study first demonstrated that hucMSC-Exos may ameliorate muscle atrophy via the miR-132-3p/FoxO3 axis. These data may provide novel and valuable insights into the clinical transformation of hucMSC-Exos for the treatment of sarcopenia.

The translational potential of this article

HucMSC-Exos are easily available for clinical application, this study further consolidates the evidence for the clinical transformation potential of hucMSC-Exos for sarcopenia and provides its new target pathway.

Dietary supplementation with Lacticaseibacillus rhamnosus IDCC3201 alleviates sarcopenia by modulating the gut microbiota and metabolites in dexamethasone-induced models

Probiotics can exert direct or indirect influences on various aspects of health claims by altering the composition of the gut microbiome and producing bioactive metabolites. The aim of this study was to examine the effect of Lacticaseibacillus rhamnosus IDCC3201 on skeletal muscle atrophy in dexamethasone-induced C2C12 cells and a mouse animal model. Dexamethasone treatment significantly reduced C2C12 muscle cell viability, myotube diameter, and levels of muscle atrophic markers (Atrogin-1 and MuRF-1). These effects were alleviated by conditioned media (CM) and cell extract (EX) derived from L. rhamnosus IDCC3201. In addition, we assessed the in vivo therapeutic effect of L. rhamnosus IDCC3201 in a mouse model of dexamethasone (DEX)-induced muscle atrophy. Supplementation with IDCC3201 resulted in significant enhancements in body composition, particularly in lean mass, muscle strength, and myofibril size, in DEX-induced muscle atrophy mice. In comparison to the DEX-treatment group, the normal and DEX + L. rhamnosus IDCC3201 groups showed a higher transcriptional level of myosin heavy chain family genes (MHC1, MHC1b, MHC2A, 2bB, and 2X) and a reduction in atrophic muscle makers. These analyses revealed that L. rhamnosus IDCC3201 supplementation led to increased production of branched-chain amino acids (BCAAs) and improved the Allobaculum genus within the gut microbiota of muscle atrophy-induced groups. Taken together, our findings suggest that L. rhamnosus IDCC3201 represents a promising dietary supplement with the potential to alleviate sarcopenia by modulating the gut microbiome and metabolites.

Gromwell ameliorates glucocorticoid-induced muscle atrophy through the regulation of Akt/mTOR pathway

BACKGROUND

Muscle atrophy is characterized by decreased muscle mass, function, and strength. Synthetic glucocorticoids, including dexamethasone (Dexa), are commonly used to treat autoimmune diseases. However, prolonged exposure of Dexa with high dose exerts severe side effects, including muscle atrophy. The purpose of this study was to investigate whether Gromwell root extract (GW) can prevent Dexa-induced muscle atrophy in C2C12 cells and mice and to characterize the composition of GW to identify bioactive compounds.

METHODS

For in vitro experiments, GW (0.5 and 1 µg/mL) or lithospermic acid (LA, 5 and 10 µM) was added to C2C12 myotubes on day 4 of differentiation and incubated for 24 h, along with 50 µM Dexa. For in vivo experiment, four-week-old male C57BL/6 mice were randomly divided into the four following groups (n = 7/group): Con group, Dexa group, GW0.1 group, and GW0.2 group. Mice were fed experimental diets of AIN-93 M with or without 0.1 or 0.2% GW for 4 weeks. Subsequently, muscle atrophy was induced by administering an intraperitoneal injection of Dexa at a dose of 15 mg/kg/day for 38 days, in conjunction with dietary intake.

RESULTS

In Dexa-induced myotube atrophy, treatment with GW increased myotube diameter, reduced the expression of muscle atrophy markers, and enhanced the expression of myosin heavy chain (MHC) isoforms in C2C12 cells. Supplementation with the GW improved muscle function and performance in mice with Dexa-induced muscle atrophy, evidenced in the grip strength and running tests. The GW group showed increased lean body mass, skeletal muscle mass, size, and myosin heavy chain isoform expression, along with reduced skeletal muscle atrophy markers in Dexa-injected mice. Supplementation with GW increased protein synthesis and decreased protein degradation through the Akt/mammalian target of rapamycin and glucocorticoid receptor/forkhead box O3 signaling pathways, respectively. We identified LA as a potential bioactive component of the GW. LA treatment increased myotube diameter and decreased the expression of muscle atrophy markers in Dexa-induced C2C12 cells.

CONCLUSIONS

These findings underscore the potential of the GW in preventing Dexa-induced skeletal muscle atrophy and highlight the contribution of LA to its effects.

Exploring the mechanism and phytochemicals in Psoraleae Fructus-induced hepatotoxicity based on RNA-seq, in vitro screening and molecular docking

Psoraleae Fructus (PF) is a widely-used herb with diverse pharmacological activities, while its related hepatic injuries have aroused public concerns. In this work, a systematic approach based on RNA sequencing (RNA-seq), high-content screening (HCS) and molecular docking was developed to investigate the potential mechanism and identify major phytochemicals contributed to PF-induced hepatotoxicity. Animal experiments proved oral administration of PF water extracts disturbed lipid metabolism and promoted hepatic injuries by suppressing fatty acid and cholesterol catabolism. RNA-seq combined with KEGG enrichment analysis identified mitochondrial oxidative phosphorylation (OXPHOS) as the potential key pathway. Further experiments validated PF caused mitochondrial structure damage, mtDNA depletion and inhibited expressions of genes engaged in OXPHOS. By detecting mitochondrial membrane potential and mitochondrial superoxide, HCS identified bavachin, isobavachalcone, bakuchiol and psoralidin as most potent mitotoxic compounds in PF. Moreover, molecular docking confirmed the potential binding patterns and strong binding affinity of the critical compounds with mitochondrial respiratory complex. This study unveiled the underlying mechanism and phytochemicals in PF-induced liver injuries from the view of mitochondrial dysfunction.

Heme oxygenase-1: A potential therapeutic target for improving skeletal muscle atrophy

Skeletal muscle atrophy is a common muscle disease that is directly caused by an imbalance in protein synthesis and degradation. At the histological level, it is mainly characterized by a reduction in muscle mass and fiber cross-sectional area (CSA). Patients with skeletal muscle atrophy present with reduced motor ability, easy fatigue, and poor life quality. Heme oxygenase-1 (HO-1) is an inducible enzyme that catalyzes the degradation of heme and has attracted much attention for its anti-oxidation effects. In addition, there is growing evidence that HO-1 plays an important role in anti-inflammatory, anti-apoptosis, pro-angiogenesis, and maintaining skeletal muscle homeostasis, making it a potential therapeutic target for improving skeletal muscle atrophy. Here, we review the pathogenesis of skeletal muscle atrophy, the biology of HO-1 and its regulation, and the biological function of HO-1 in skeletal muscle homeostasis, with a specific focus on the role of HO-1 in skeletal muscle atrophy, aiming to observe the therapeutic potential of HO-1 for skeletal muscle atrophy.

Oxidative stress: roles in skeletal muscle atrophy

Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.

Network pharmacology-based identification of bioavailable anti-inflammatory agents from Psoralea corylifolia L. in an experimental colitis model

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional oriental medicine, the dried seeds of Psoralea corylifolia L. (PC) have been used to treat various diseases, including gastrointestinal, urinary, orthopedic, diarrheal, ulcer, and inflammatory disorders.

AIM OF THE STUDY

Although its various biological properties are well-known, there is no information on the therapeutic effects and bioavailable components of PC against inflammatory bowel disease. Therefore, we focused on the relationship between hydroethanolic extract of PC (EPC) that ameliorates colitis in mice and bioactive constituents of EPC that suppress pro-inflammatory cytokines in macrophages.

MATERIALS AND METHODS

We investigated the therapeutic effects of EPC in a dextran sulfate sodium-induced colitis mouse model and identified the orally absorbed components of EPC using UPLC-MS/MS analysis. In addition, we evaluated and validated the mechanism of action of the bioavailable constituents of EPC using network pharmacology analysis. The effects on nitric oxide (NO) and inflammatory cytokines were measured by Griess reagent and enzyme linked immunosorbent assay in lipopolysaccharide (LPS)-induced macrophages.

RESULTS

In experimental colitis, EPC improved body weight loss, colon length shortening, and disease activity index. Moreover, EPC reduced the serum levels of pro-inflammatory cytokines and histopathological damage to the colon. Network pharmacological analysis identified 13 phytochemicals that were bioavailable following oral administration of EPC, as well as their potential anti-inflammatory effects. 11 identified EPC constituents markedly reduced the overproduction of NO, tumor necrosis factor-α, and/or interleukin-6 in macrophages induced by LPS. The LPS-induced expression of the nuclear factor kappa-light-chain-enhancer of activated B cells reporter gene was reduced by the 4 EPC constituents.

CONCLUSIONS

The results indicate that the protective activity of EPC against colitis is a result of the additive effects of each constituent on the expression of inflammatory cytokines. Therefore, it suggests that 11 bioavailable phytochemicals of EPC could aid in the management of intestinal inflammation, and also provides useful insights into the clinical application of PC for the treatment of inflammatory bowel diseases.

Is dexamethasone-induced muscle atrophy an alternative model for naturally aged sarcopenia model?

Background

Primary sarcopenia is usually known as age-related skeletal muscle loss; however, other factors like endocrine, lifestyle and inflammation can also cause muscle loss, known as secondary sarcopenia. Although many studies have used different sarcopenia animal models for exploring the underlying mechanism and therapeutic approaches for sarcopenia, limited study has provided evidence of the relevance of these animal models. This study aims to investigate the similarity and difference in muscle qualities between primary and secondary sarcopenia mice models, using naturally aged mice and dexamethasone-induced mice.

Methods

21-month-old mice were used as naturally aged primary sarcopenia mice and 3-month-old mice received daily intraperitoneal injection of dexamethasone (20 mg/ kg body weight) for 10 days were used as secondary sarcopenia model. This study provided measurements for muscle mass and functions, including Dual-energy X-ray absorptiometry (DXA) scanning, handgrip strength test and treadmill running to exhaustion test. Besides, muscle contraction, muscle fibre type measurements and gene expression were also performed to provide additional information on muscle qualities.

Results

The results suggest two sarcopenia animal models shared a comparable decrease in forelimb lean mass, muscle fibre size, grip strength and muscle contraction ability. Besides, the upregulation of protein degradation genes was also observed in two sarcopenia animal models. However, only primary sarcopenia mice were identified with an early stage of mtDNA deletion.

Conclusion

Collectively, this study evaluated that the dexamethasone-induced mouse model could be served as an alternative model for primary sarcopenia, according to the comparable muscle mass and functional changes. However, whether dexamethasone-induced mice can be used as an animal model when studying the molecular mechanisms of sarcopenia needs to be carefully evaluated.

The translational potential of this article

The purpose of sarcopenia research is to investigate appropriate treatments for reversing the loss of skeletal muscle mass and functions. Using animal models for the preclinical study could predict the safety and efficacy of the treatments. This study compared the typical age-related sarcopenia mice model and dexamethasone-induced secondary sarcopenia mice to provide evidence of the pathological and functional changes in the mice models.

Isodorsmanin A Prevents Inflammatory Response in LPS-Stimulated Macrophages by Inhibiting the JNK and NF-κB Signaling Pathways

Natural and synthetic chalcones exhibit anti-inflammatory, antitumoral, antibacterial, antifungal, antimalarial, and antitubercular activities. Isodorsmanin A (IDA), a chalcone, is a well-known constituent of the dried seeds of Psoralea corylifolia L. (PC). Although other constituents of PC have been widely investigated, there are no studies on the biological properties of IDA. In this study, we focused on the anti-inflammatory effects of IDA and evaluated its effects on lipopolysaccharide (LPS)-stimulated macrophages. The results showed that IDA suppressed the production of inflammatory mediators (nitric oxide [NO] and prostaglandin E₂ [PGE₂]) and proinflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and interleukin-1β [IL-1β]) without cytotoxicity. In addition, it downregulated the mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) within the treatment concentrations. In our mechanistic studies, IDA inhibited the phosphorylation of the c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase (MAPK), and protected the nuclear factor of the kappa light polypeptide gene enhancer in the B-cells' inhibitor, alpha (IκB-α), from degradation, thus preventing the activation of the nuclear factor kappa-light-chain-enhancer of activated B cells' (NF-κB) transcription factor. Our results suggest that IDA is a promising compound for attenuating excessive inflammatory responses.

The Inhibition of Autophagy and Pyroptosis by an Ethanol Extract of Nelumbo nucifera Leaf Contributes to the Amelioration of Dexamethasone-Induced Muscle Atrophy

Muscle atrophy is characterized by a decline in muscle mass and function. Excessive glucocorticoids in the body due to aging or drug treatment can promote muscle wasting. In this study, we investigated the preventive effect of Nelumbo nucifera leaf (NNL) ethanolic extract on muscle atrophy induced by dexamethasone (DEX), a synthetic glucocorticoid, in mice and its underlying mechanisms. The administration of NNL extract increased weight, cross-sectional area, and grip strength of quadriceps (QD) and gastrocnemius (GA) muscles in DEX-induced muscle atrophy in mice. The NNL extract administration decreased the expression of muscle atrophic factors, such as muscle RING-finger protein-1 and atrogin-1, and autophagy factors, such as Beclin-1, microtubule-associated protein 1A/1B-light chain 3 (LC3-I/II), and sequestosome 1 (p62/SQSTM1) in DEX-injected mice. DEX injection increased the protein expression levels of NOD-like receptor pyrin domain-containing protein 3 (NLRP3), cleaved-caspase-1, interleukin-1beta (IL-1β), and cleaved-gasdermin D (GSDMD), which were significantly reduced by NNL extract administration (500 mg/kg/day). In vitro studies using C2C12 myotubes also revealed that NNL extract treatment inhibited the DEX-induced increase in autophagy factors, pyroptosis-related factors, and NF-κB. Overall, the NNL extract prevented DEX-induced muscle atrophy by downregulating the ubiquitin-proteasome system, autophagy pathway, and GSDMD-mediated pyroptosis pathway, which are involved in muscle degradation.

Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta-analysis of randomized controlled trials

Probiotics have shown potential to counteract sarcopenia, although the extent to which they can influence domains of sarcopenia such as muscle mass and strength in humans is unclear. The aim of this systematic review and meta-analysis was to explore the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. A literature search of randomized controlled trials (RCTs) was conducted through PubMed, Scopus, Web of Science and Cochrane Library from inception until June 2022. Eligible RCTs compared the effect of probiotic supplementation versus placebo on muscle and total lean mass and global muscle strength (composite score of all muscle strength outcomes) in adults (>18 years). To evaluate the differences between groups, a meta-analysis was conducted using the random effects inverse-variance model by utilizing standardized mean differences. Twenty-four studies were included in the systematic review and meta-analysis exploring the effects of probiotics on muscle mass, total lean mass and global muscle strength. Our main analysis (k = 10) revealed that muscle mass was improved following probiotics compared with placebo (SMD: 0.42, 95% CI: 0.10-0.74, I²  = 57%, P = 0.009), although no changes were revealed in relation to total lean mass (k = 12; SMD: -0.03, 95% CI: -0.19 - 0.13, I²  = 0%, P = 0.69). Interestingly, a significant increase in global muscle strength was also observed among six RCTs (SMD: 0.69, 95% CI: 0.33-1.06, I²  = 64%, P = 0.0002). Probiotic supplementation enhances both muscle mass and global muscle strength; however, no beneficial effects were observed in total lean mass. Investigating the physiological mechanisms underpinning different ageing groups and elucidating appropriate probiotic strains for optimal gains in muscle mass and strength are warranted.

Bavachin and Corylifol A Improve Muscle Atrophy by Enhancing Mitochondria Quality Control in Type 2 Diabetic Mice

Type 2 diabetes reduces muscle mass and function. Chronic inflammation and mitochondrial dysfunction play critical roles in muscle atrophy pathogenesis. Here, we investigated the effects of bavachin and corylifol A from Psoralea corylifolia L. seeds on muscle atrophy in dexamethasone-treated mice and in db/db mice. Bavachin and corylifol A enhanced muscle strength and muscle mass in dexamethasone-treated mice. In diabetic mice, they enhanced muscle strength and cross-sectional areas. Bavachin and corylifol A suppressed inflammatory cytokine (interleukin-6 and tumor necrosis factor-α) expression levels by downregulating nuclear factor-κB phosphorylation. They decreased the muscle atrophic factor (myostatin, atrogin-1, and muscle RING finger-1) expression levels. They activated the AKT synthetic signaling pathway and induced a switch from fast-type glycolytic fibers (type 2B) to slow-type oxidative fibers (types I and 2A). They increased mitochondrial biogenesis and dynamic factor (optic atrophy-1, mitofusin-1/2, fission, mitochondrial 1, and dynamin 1-like) expression levels via the AMP-activated protein kinase-peroxisome proliferator-activated receptor gamma coactivator 1-alpha signaling pathway. They also improved mitochondrial quality by upregulating the mitophagy factor (p62, parkin, PTEN-induced kinase-1, and BCL2-interacting protein-3) expression levels. Therefore, bavachin and corylifol A exert potential therapeutic effects on muscle atrophy by suppressing inflammation and improving mitochondrial function.