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MOTS-c Impact on Muscle Cell Differentiation and Metabolism Across Fiber Types
Background/Aims: MOTS-c belongs to a group of mitochondrial peptides involved in metabolic processes in the body. This peptide has garnered increasing attention since its discovery in 2015 because of its potential to ameliorate metabolic parameters in animals with diabetes or insulin resistance. MOTS-c is involved in muscle metabolism; however, little is known about its role in fiber differentiation. Materials: We conducted a study to explore the effect of MOTS-c on cellular processes using the C2C12 and L6 cell lines, representing different metabolic types of muscle fibers. The research methods were real-time PCR, Western blot, and lipid accumulation measurement. Results: >Notably, our investigations revealed that MOTS-c increased the survival of C2C12 cells at doses of 10 and 100 nM (p<0.01) and stimulated the phosphorylation of extracellular signal-regulated kinase within 5 min of incubation (p<0.05). Remarkably, these effects were not observed in L6 cells; however, both cell lines showed a reduced rate of proliferation. Furthermore, MOTS-c promotes the differentiation of C2C12 cells by increasing the expression of muscle regulatory factors, but it does not produce such an effect in L6 cells. Additionally, cells were treated with physiological concentrations of free fatty acids and MOTS-c, unveiling an augmentation in lipid accumulation observed in L6 cells and a decrease in lipid accumulation in C2C12 cells. Conclusion: In conclusion, our findings have suggested a diverse response to MOTS-c depending on the type of muscle fibers, particularly in the domains of survival, cell differentiation, and lipid accumulation.
MOTS-c modulates pancreatic islet function in rats and pigs in vitro
Abstract MOTS-c is a promising regulator of metabolism and energy homeostasis. While its effects have been studied in cell lines, our team aimed to investigate its influence on more complex structures—specifically, isolated pancreatic islets. We used two animal models: the rat, which is commonly studied, and the pig, which shares greater physiological similarities with humans. This study assessed the expression and secretion of insulin and glucagon, the expression of their receptors, cell viability, and cell death following MOTS-c treatment of the islets. Additionally, we examined how MOTS-c secretion is affected by different incubation media, such as the presence of free fatty acids, pancreatic hormones, and different glucose concentrations. The results indicate that MOTS-c impacts pancreatic islet physiology by, for example, reducing insulin and glucagon secretion and enhancing cell viability. Notably, the effects differed between the two species, which may be attributed to anatomical differences in their pancreatic islets or structural variations in rat and pig MOTS-c. These facts may lead to the conclusion that if MOTS-c may be helpful in human medicine, the pig model should be considered another valuable choice.
MOTS-c regulates pancreatic alpha and beta cell functions in vitro
AbstractThe aim of this study is to determine the influence of the mitochondrial open-reading-frame of the twelve S rRNA-c (MOTS-c) peptide on pancreatic cell physiology. Moreover, in this study, we examined the changes in MOTS-c secretion and expression under different conditions. Our experiments were conducted using laboratory cell line cultures, specifically the INS-1E and αTC-1 cell lines, which represent β and α pancreatic cells, respectively. As the pancreas is an endocrine organ, we also tested its hormone regulation capabilities. Furthermore, we assessed the secretion of MOTS-c after incubating the cells with glucose and free fatty acids. Additionally, we examined key cell culture parameters such as cell viability, proliferation, and apoptosis. The results obtained from this study show that MOTS-c has a significant impact on the physiology of pancreatic cells. Specifically, it lowers insulin secretion and expression in INS-1E cells and enhances glucagon secretion and expression in αTC-1 cells. Furthermore, MOTS-c affects cell viability and apoptosis. Interestingly, insulin and glucagon affect the MOTS-c secretion as well as glucose and free fatty acids. These experiments clearly show that MOTS-c is an important regulator of pancreatic metabolism, and there are numerous properties of MOTS-c yet to be discovered.