Synergistic Effect of Hydrogen and 5-Aza on Myogenic Differentiation through the p38 MAPK Signaling Pathway in Adipose-Derived Mesenchymal Stem Cells.

Background and Objectives: This study aims to clarify the systems underlying regulation and regulatory roles of hydrogen combined with 5-Aza in the myogenic differentiation of adipose mesenchymal stem cells (ADSCs). Methods and Results: In this study, ADSCs acted as an in vitro myogenic differentiating mode. First, the Alamar blue Staining and mitochondrial tracer technique were used to verify whether hydrogen combined with 5-Aza could promote cell proliferation. In addition, this study assessed myogenic differentiating markers (e.g., Myogenin, Mhc and Myod protein expressions) based on the Western blotting assay, analysis on cellular morphological characteristics (e.g., Myotube number, length, diameter and maturation index), RT-PCR (Myod, Myogenin and Mhc mRNA expression) and Immunofluorescence analysis (Desmin, Myosin and ß-actin protein expression). Finally, to verify the mechanism of myogenic differentiation of hydrogen-bound 5-Aza, we performed bioinformatics analysis and Western blot to detect the expression of p-P38 protein. Hydrogen combined with 5-Aza significantly enhanced the proliferation and myogenic differentiation of ADSCs in vitro by increasing the number of single-cell mitochondria and upregulating the expression of myogenic biomarkers such as Myod, Mhc and myotube formation. The expressions of p-P38 was up-regulated by hydrogen combined with 5-Aza. The differentiating ability was suppressed when the cells were cultivated in combination with SB203580 (p38 MAPK signal pathway inhibitor). Conclusions: Hydrogen alleviates the cytotoxicity of 5-Aza and synergistically promotes the myogenic differentiation capacity of adipose stem cells via the p38 MAPK pathway. Thus, the mentioned results present insights into myogenic differentiation and are likely to generate one potential alternative strategy for skeletal muscle related diseases.

Molecular Hydrogen Promotes Adipose-derived Stem Cell Myogenic Differentiation via Regulation of Mitochondria.

BACKGROUND: Acute skeletal muscle injuries are common physical or sports traumas. Cellular therapy has excellent potential for regeneration after skeletal muscle injury. Adipose-derived stem cells (ADSCs) are a more accessible type of stem cell. However, it has a low survival rate and differentiation efficiency in the oxidative stress-rich microenvironment after transplantation. Although molecular hydrogen (H2) possesses anti-inflammatory and antioxidant biological properties, its utility in mitochondrial and stem cell research has not been adequately explored. OBJECTIVE: This study aimed to reveal the role of H2 on adipose-derived stem cells' myogenic differentiation. METHODS: The protective effects of H2 in ADSCs were evaluated by MTT assay, live-dead cell staining, western blot analysis, immunofluorescence staining, confocal imaging, and transmission electron microscopy. RESULTS: An appropriate volume fraction of H2 significantly decreased mitochondrial reactive oxygen species (ROS) levels, increased the number of mitochondria, and promoted mitophagy, thus enhancing the survival and myogenic differentiation of ADSCs. CONCLUSION: This study reveals the application potential of H2 in skeletal muscle diseases or other pathologies related to mitochondrial dysfunction.

Porous Se@SiO2 nanoparticles improve oxidative injury to promote muscle regeneration via modulating mitochondria.

Background: Acute skeletal muscle injuries are common among physical or sports traumas. The excessive oxidative stress at the site of injury impairs muscle regeneration. The authors have recently developed porous Se@SiO2 nanoparticles (NPs) with antioxidant properties. Methods: The protective effects were evaluated by cell proliferation, myogenic differentiation and mitochondrial activity. Then, the therapeutic effect was investigated in a cardiotoxin-induced muscle injury rat model. Results: Porous Se@SiO2 NPs significantly protected the morphological and functional stability of mitochondria, thus protecting satellite cells from H2O2-induced damage to cell proliferation and myogenic differentiation. In the rat model, intervention with porous Se@SiO2 NPs promoted muscle regeneration. Conclusion: This study reveals the application potential of porous Se@SiO2 NPs in skeletal muscle diseases related to mitochondrial dysfunction.

Muscle injuries are very common in daily life and in sports. When a muscle is injured, the local response inhibits the regeneration and differentiation of stem cells inside the muscle, thus hindering muscle regeneration. The authors have recently developed a nanoparticle with the ability to protect muscle stem cell function, promote stem cell proliferation and differentiation and facilitate muscle regeneration after skeletal muscle injury in rats. Thus, this study reveals the potential of porous Se@SiO₂ nanoparticles in skeletal muscle diseases associated with mitochondrial dysfunction.

Disuse-associated loss of the protease LONP1 in muscle impairs mitochondrial function and causes reduced skeletal muscle mass and strength.

Mitochondrial proteolysis is an evolutionarily conserved quality-control mechanism to maintain proper mitochondrial integrity and function. However, the physiological relevance of stress-induced impaired mitochondrial protein quality remains unclear. Here, we demonstrate that LONP1, a major mitochondrial protease resides in the matrix, plays a role in controlling mitochondrial function as well as skeletal muscle mass and strength in response to muscle disuse. In humans and mice, disuse-related muscle loss is associated with decreased mitochondrial LONP1 protein. Skeletal muscle-specific ablation of LONP1 in mice resulted in impaired mitochondrial protein turnover, leading to mitochondrial dysfunction. This caused reduced muscle fiber size and strength. Mechanistically, aberrant accumulation of mitochondrial-retained protein in muscle upon loss of LONP1 induces the activation of autophagy-lysosome degradation program of muscle loss. Overexpressing a mitochondrial-retained mutant ornithine transcarbamylase (ΔOTC), a known protein degraded by LONP1, in skeletal muscle induces mitochondrial dysfunction, autophagy activation, and cause muscle loss and weakness. Thus, these findings reveal a role of LONP1-dependent mitochondrial protein quality-control in safeguarding mitochondrial function and preserving skeletal muscle mass and strength, and unravel a link between mitochondrial protein quality and muscle mass maintenance during muscle disuse.