Lespedeza bicolor extract supplementation reduced hyperglycemia-induced skeletal muscle damage by regulation of AMPK/SIRT/PGC1α-related energy metabolism in type 2 diabetic mice

Effects of Bioconverted Guava Leaf (Psidium guajava L.) Extract on Skeletal Muscle Damage by Regulation of Ubiquitin-Proteasome System and Apoptosis in Type 2 Diabetic Mice

Skeletal muscle atrophy is one of the serious complications of diabetes, which increases the risk of frailty, falls, and mortality. However, interventions for muscle atrophy are limited, and research is needed regarding the treatment of muscle wasting. Recently, the bioconversion of natural products by lactic acid bacteria has been highlighted as a possibility to improve the bioavailability of active ingredients. This process also produces metabolites, which are key signaling mediators for a variety of physiological functions. This study investigated the effect of bioconverted guava leaf (Psidium guajava L., GL) by Lactobacillus plantarum on hyperglycemia-induced skeletal muscle atrophy in type 2 diabetes mellites (T2DM) mice. Diabetes was induced by a high-fat diet with a two-time streptozotocin (STZ) injection (60 mg/kg BW) in male C57BL/6J mice. After diabetes was induced (a fasting blood glucose level (FBG) ≥ 300 mg/dL), the mice were administered with GL (100 mg/kg/day) or bioconverted GL (FGL) (50 mg/kg/day) by oral gavage for 14 weeks. FGL contains different substances such as hydroxyl-isocaproic acid and hydroxyl-isovaleric acid compared to GLE itself, which have potential to prevent muscle degradation in T2DM mice. GL and FGL supplementation reduced the FBG level in T2DM mice. In addition, GL and FGL supplementation enhanced muscle strength, the skeletal muscle cross-sectional area, and ameliorated ubiquitin-proteasome system (UPS)-related pathways in T2DM mice. On the other hand, GLE supplementation ameliorated glucose tolerance demonstrated by oral glucose tolerance test and enhanced insulin signaling pathway. In addition, only FGL supplementation attenuated skeletal muscle inflammation and apoptosis with an improved mammalian target of the rapamycin (mTOR)-autophagy-related pathway. Although administered at a half dose of GLE, FGL demonstrated greater efficacy in regulating the expression of these molecular markers. The result suggests that even GL itself has anti-diabetic effects, and the functionality would be enhanced by the bioconversion of GL with L. Plantarum, which has an additive or/and a synergistic effect. Taken together, FGL could be used as a potential nutraceutical to attenuate muscle degradation by the inhibition of inflammation, the UPS, and the apoptosis pathway.

The Functions and Regulatory Mechanisms of Histone Modifications in Skeletal Muscle Development and Disease

Skeletal muscle development is a complex biological process regulated by many factors, such as transcription factors, signaling pathways, and epigenetic modifications. Histone modifications are important epigenetic regulatory factors involved in various biological processes, including skeletal muscle development, and play a crucial role in the pathogenesis of skeletal muscle diseases. Histone modification regulators affect the expression of many genes involved in skeletal muscle development and disease by adding or removing certain chemical modifications. In this review, we comprehensively summarize the functions and regulatory activities of the histone modification regulators involved in skeletal muscle development, regeneration, and disease.

Flavonoids Derived from the Roots of Lespedeza bicolor Inhibit the Activity of SARS-CoV Papain-like Protease

Despite the now infamous coronavirus disease outbreaks caused by severe acute respiratory syndrome coronavirus (SARS-CoV), this virus continues to be a threat to the global population. Although a huge research effort has targeted SARS-CoV, no report exists regarding natural small molecules targeting one of its key enzymes, papain-like protease (PLpro). In this study, nine flavonoids displaying SARS-CoV PLpro inhibitory activity were isolated from the root bark of Lespedeza bicolor. The compounds were identified as erythrabyssin II (1), lespebuergine G4 (2), 1-methoxyerythrabyssin II (3), bicolosin A (4), bicolosin B (5), bicolosin (6), xanthoangelol (7), (±)-lespeol (8), and parvisoflavanone (9). Most compounds (1-4 and 6-8) inhibited SARS-CoV PLpro activity in a dose-dependent manner, with their Kis ranging from 5.56 to 75.37 μM. The structure-activity analysis of pterocarpans (1-6) showed that activity was enhanced by C1-OCH3, but it was reduced by C8-CH3. A mechanistic analysis revealed that all inhibitors were noncompetitive. Some of the key compounds isolated in this study are pterocarpans, which are abundantly present in the Leguminosae family. Overall, a rich source of SARS-CoV papain-like protease inhibitors was identified in this study.

Lespedeza bicolor root extract exerts anti-TNBC potential by regulating FAK-related signalling pathways

Lespedeza bicolor is a shrub plant that has been widely distributed in East Asia. The methanol extract from its LBR has been shown to exhibit anticancer and anti-bacterial effects. However, its anticancer efficacy in TNBC remains uncertain. This work aimed to study the anti-TNBC effect of LBR ethanol extract and its underlying mechanism. LBR triggered the cell death in TNBC through inhibiting cell proliferation, S-phase cell arrest, and induction of apoptosis. RNA-seq analysis revealed that the genes altered by LBR treatment were predominantly enriched in the cell adhesion. Notably, LBR inhibited phosphorylation and distribution of FAK. Furthermore, LBR demonstrated significant anticancer activity in xenograft tumors in mice through inhibiting cancer cell growth and inducing apoptosis. This work demonstrated the anticancer efficiency of LBR in TNBC without causing significant adverse effect, which providing a foundation for developing LBR based chemotherapeutic agents for breast cancer therapy.

Diabetes-induced muscle wasting: molecular mechanisms and promising therapeutic targets

Diabetes has become a serious public health crisis, presenting significant challenges to individuals worldwide. As the largest organ in the human body, skeletal muscle is a significant target of this chronic disease, yet muscle wasting as a complication of diabetes is still not fully understood and effective treatment methods have yet to be developed. Here, we discuss the targets involved in inducing muscle wasting under diabetic conditions, both validated targets and emerging targets. Diabetes-induced skeletal muscle wasting is known to involve changes in various signaling molecules and pathways, such as protein degradation pathways, protein synthesis pathways, mitochondrial function, and oxidative stress inflammation. Recent studies have shown that some of these present potential as promising therapeutic targets, including the neuregulin 1/epidermal growth factor receptor family, advanced glycation end-products, irisin, ferroptosis, growth differentiation factor 15 and more. This study's investigation and discussion of such pathways and their potential applications provides a theoretical basis for the development of clinical treatments for diabetes-induced muscle wasting and a foundation for continued focus on this disease.

Guava leaf extract attenuated muscle proteolysis in dexamethasone induced muscle atrophic mice via ubiquitin proteasome system, mTOR-autophagy, and apoptosis pathway

Muscle atrophy is the waste or loss of muscle mass and is caused by physical inactivity, aging, or diseases such as diabetes, cancer, and heart failure. The number of patients suffering from musculoskeletal disorders is expected to increase in the future. However, intervention for muscle atrophy is limited, so research on treatment for muscle wasting is needed. This study hypothesized that guava leaf (Psidium guajava L. [GL]) would have ameliorative effects on muscle atrophy by regulation of protein degradation pathways in a dexamethasone (DEX)-induced muscle atrophy mice model. Muscle atrophy was induced by DEX injection for 28 days in 7 week-old-male ICR mice. Then, low-dose GL (LGL, 200 mg/kg) or high-dose GL (HGL, 500 mg/kg) extract (GLE) was supplemented by oral gavage for 21 days. Muscle strength, calf thickness, and body composition were analyzed. Histopathological changes in the gastrocnemius muscle were examined using hematoxylin and eosin staining, and molecular pathways related to muscle degradation were analyzed by western blots. GLE treatment regardless of dose increased muscle strength in mice with muscle atrophy accompanied by attenuating autophagy related pathway in the DEX-induced muscle atrophy mice. Moreover, a high dose of GLE treatment ameliorated ubiquitin proteasome system and apoptosis in the DEX-induced muscle atrophy mice. This study suggested that GLE could be helpful to improve muscle health and alleviate proteolysis by regulation of the ubiquitin-proteasome system, autophagy, and apoptosis, which are involved in muscle degradation. In conclusion, GLE could be a potential nutraceutical to prevent muscle atrophy.

Pathogenesis and comprehensive treatment strategies of sarcopenia in elderly patients with type 2 diabetes mellitus

Sarcopenia and diabetes are two age-related diseases that are common in the elderly population, and have a serious effect on their general health and quality of life. Sarcopenia refers to the progressive loss of muscle mass, strength and function, whereas diabetes is a chronic disease characterized by elevated blood sugar levels. The comorbidity of sarcopenia and diabetes is particularly concerning, as people with diabetes have a higher risk of developing sarcopenia due to the combination of insulin resistance, chronic inflammation and reduced physical activity. In contrast, sarcopenia destroyed blood sugar control and exacerbated the development of people with diabetes, leading to the occurrence of a variety of complications. Fortunately, there are a number of effective treatment strategies for sarcopenia in people with diabetes. Physical exercise and a balanced diet with enough protein and nutrients have been proved to enhance the muscular quality and strength of this population. Additionally, pharmacological therapies and lifestyle changes can optimize blood sugar control, which can prevent further muscle loss and improve overall health outcomes. This review aims to summarize the pathogenesis and comprehensive treatment strategies of sarcopenia in elderly patients with type 2 diabetes, which help healthcare professionals recognize their intimate connection and provide a new vision for the treatment of diabetes and its complications in this population. Through early identification and comprehensive treatment, it is possible to improve the muscle function and general quality of life of elderly with diabetes and sarcopenia.

The epigenetic regulatory effect of histone acetylation and deacetylation on skeletal muscle metabolism-a review

Skeletal muscles, the largest organ responsible for energy metabolism in most mammals, play a vital role in maintaining the body's homeostasis. Epigenetic modification, specifically histone acetylation, serves as a crucial regulatory mechanism influencing the physiological processes and metabolic patterns within skeletal muscle metabolism. The intricate process of histone acetylation modification involves coordinated control of histone acetyltransferase and deacetylase levels, dynamically modulating histone acetylation levels, and precisely regulating the expression of genes associated with skeletal muscle metabolism. Consequently, this comprehensive review aims to elucidate the epigenetic regulatory impact of histone acetylation modification on skeletal muscle metabolism, providing invaluable insights into the intricate molecular mechanisms governing epigenetic modifications in skeletal muscle metabolism.

Aerobic Exercise Ameliorates Muscle Atrophy Induced by Methylglyoxal via Increasing Gastrocnemius and Extensor Digitorum Longus Muscle Sensitivity

Muscle atrophy is characterized by the loss of muscle function. Many efforts are being made to prevent muscle atrophy, and exercise is an important alternative. Methylglyoxal is a well-known causative agent of metabolic diseases and diabetic complications. This study aimed to evaluate whether methylglyoxal induces muscle atrophy and to evaluate the ameliorative effect of moderate-intensity aerobic exercise in a methylglyoxal-induced muscle atrophy animal model. Each mouse was randomly divided into three groups: control, methylglyoxal-treated, and methylglyoxal-treated within aerobic exercise. In the exercise group, each mouse was trained on a treadmill for 2 weeks. On the last day, all groups were evaluated for several atrophic behaviors and skeletal muscles, including the soleus, plantaris, gastrocnemius, and extensor digitorum longus were analyzed. In the exercise group, muscle mass was restored, causing in attenuation of muscle atrophy. The gastrocnemius and extensor digitorum longus muscles showed improved fiber cross-sectional area and reduced myofibrils. Further, they produced regulated atrophy-related proteins (i.e., muscle atrophy F-box, muscle RING-finger protein-1, and myosin heavy chain), indicating that aerobic exercise stimulated their muscle sensitivity to reverse skeletal muscle atrophy. In conclusion, shortness of the gastrocnemius caused by methylglyoxal may induce the dynamic imbalance of skeletal muscle atrophy, thus methylglyoxal may be a key target for treating skeletal muscle atrophy. To this end, aerobic exercise may be a powerful tool for regulating methylglyoxal-induced skeletal muscle atrophy.

Annona muricate Extract Supplementation Contributes to Improve Aberrant Multi-Organ Energy Metabolism via Muscle-Brain Connectivity in Diabetic Mice

Type 2 diabetes mellitus (T2DM) is related with the incidence of sarcopenia and cognitive impairment that reduces quality of life in the elderly. Recent evidence has demonstrated that sarcopenia is associated with cognitive dysfunction, and muscle-derived endocrine factors might contribute to cognitive function by the skeletal muscle-brain endocrine loop. This study investigated the beneficial effects of Annona muricata (AM, graviola) on multi-organ energy metabolism with muscle-brain connectivity via brain function-related myokines in mice. Body composition, fasting blood glucose level, insulin, HbA1c%, histopathological changes, and the protein levels of insulin-signaling, energy metabolism, neuroprotection, inflammation, and protein-degradation pathways were measured. AM extract (AME) treatment selectively enhanced insulin signaling in the skeletal muscle and hippocampus of T2DM mice. Furthermore, AME treatment effectively increased muscle-derived fibroblast growth factor 21 (FGF21), cathepsin-B (CTSB), irisin, brain-derived neurotrophic factor (BDNF), and liver-derived FGF21 that contribute to whole-body energy homeostasis. In particular, AME increased the levels of circulating myokines (FGF21, BDNF, irisin, and CTSB), and these were accordance with the hippocampal neurotrophic factors (BDNF and CTSB) in T2DM mice. In conclusion, we suggest that AME would be a potential nutraceutical for improving the energy metabolism associated with muscle-brain connectivity via brain function-related myokines in T2DM.