Aronia Upregulates Myogenic Differentiation and Augments Muscle Mass and Function Through Muscle Metabolism

Berry Fruits and Their Improving Potential on Skeletal Muscle Health and Performance: A Systematic Review of the Evidence in Animal and in Human Studies

The well-established anti-inflammatory and antioxidant properties of red fruits leave room for a biological pathway of improved muscle health promoted by berries in the diet. Our objective was to systematically review the number of trials conducted on human and animal species around the relationship between a berry diet and muscle health outcomes. Two independent examiners conducted a search for studies that utilized keywords associated with muscle health outcomes and a berry-based diet in both human and animal trials, in accordance with the PRISMA statement guidelines. The literature was searched through six electronic databases until December 2023. Screening of 152 retrieved articles resulted in a final selection of 16 reports investigating the effect of exposure to a berry-based diet and skeletal muscle health outcomes. The study protocol was registered on PROSPERO (CRD42023479682). Among the selected studies, nine involved humans and seven animal models (rats and mice). Overall, most of the studies reported positive effects on performance or muscle health. Specifically, five studies investigated the possible effects of blackcurrant on active human subjects or athletes; three studies focused on blueberry and presented results on running performance (human sample) and muscle health (rat models). The rest of the studies involved raspberries (two studies, rat models), aronia (one study, rat models), elderberry (one study, rat models), and a mixed compound (one study, rat models). In conclusion, there is some early evidence that a berry-rich diet may increase performance or muscle health, but more research is needed to fully understand the underlying biological trajectories, and thus, no firm conclusions can yet be drawn.

Mechanistic of AMPK/ACC2 regulating myoblast differentiation by fatty acid oxidation of goat

Myoblast differentiation depends on fatty acid oxidation (FAO)，and its rate-limiting enzyme acetyl-CoA carboxylase 2 (ACC2) participate in the regulation skeletal muscle development. However, the precise regulatory mechanism is still unknown. Using previous RNA-sequencing data from our laboratory, we explored the effect of ACC2 on myoblast differentiation, as a candidate gene, since its expression is higher in myoblasts of lamb (first day of age) than that of the fetus (75th day of pregnancy). Our findings show that siACC2 inhibited myoblast proliferation, promoted differentiation, and boosted mitochondrial and fatty acid oxidation activities. The effect of ACC2 on goat muscle cell differentiation was modulated by Etomoxir, a CPT1A inhibitor. Notably, the AMPK/ACC2 pathway was found to regulate fatty acid oxidation and goat muscle cell differentiation. Inhibiting the AMPK/ACC2 pathway significantly reduced CPT1A expression. These findings indicate that AMPK/ACC2 regulate goat myoblast differentiation via fatty acid oxidation, contributing to understanding the mechanism of goat skeletal muscle development.

Gouqi-derived nanovesicles (GqDNVs) inhibited dexamethasone-induced muscle atrophy associating with AMPK/SIRT1/PGC1α signaling pathway

With the increasing trend of global aging, sarcopenia has become a significant public health issue. Goji berry, also known as "Gou qi zi" in China, is a traditional Chinese herb that can enhance the structure and function of muscles and bones. Otherwise, previous excellent publications illustrated that plant-derived exosome-like nanoparticles can exert good bioactive functions in different aging or disease models. Thus, we issued the hypothesis that Gouqi-derived nanovesicles (GqDNVs) may also have the ability to improve skeletal muscle health, though the effect and its mechanism need to be explored. Hence, we have extracted GqDNVs from fresh berries of Lycium barbarum L. (goji) and found that the contents of GqDNVs are rich in saccharides and lipids. Based on the pathway annotations and predictions in non-targeted metabolome analysis, GqDNVs are tightly associated with the pathways in metabolism. In muscle atrophy model mice, intramuscular injection of GqDNVs improves the cross-sectional area of the quadriceps muscle, grip strength and the AMPK/SIRT1/PGC1α pathway expression. After separately inhibiting AMPK or PGC1α in C2C12 cells with dexamethasone administration, we have found that the activated AMPK plays the chief role in improving cell proliferation induced by GqDNVs. Furthermore, the energy-targeted metabolome analysis in the quadriceps muscle demonstrates that the GqDNVs up-regulate the metabolism of amino sugar and nucleotide sugar, autophagy and oxidative phosphorylation process, which indicates the activation of muscle regeneration. Besides, the Spearman rank analysis shows close associations between the quality and function of skeletal muscle, metabolites and expression levels of AMPK and SIRT1. In this study, we provide a new founding that GqDNVs can improve the quality and function of skeletal muscle accompanying the activated AMPK/SIRT1/PGC1α signaling pathway. Therefore, GqDNVs have the effect of anti-aging skeletal muscle as a potential adjuvant or complementary method or idea in future therapy and research.

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.