MicroRNA-668-3p inhibits myoblast proliferation and differentiation by targeting Appl1

Adiponectin regulates proliferation and differentiation of chicken skeletal muscle satellite cells via ERK1/2 and p38 signaling pathways

Skeletal muscle satellite cells (SMSCs) are critical for postnatal skeletal muscle growth and regeneration. Adiponectin plays a pivotal role in regulating muscle glucose uptake and fatty acid metabolism. However, its function in the proliferation and differentiation of chicken SMSCs remains poorly understood. In this study, we investigated the effects of adiponectin on the proliferation and differentiation of in vitro cultured chicken SMSCs. Our results demonstrated that adiponectin promoted SMSCs proliferation while inhibiting myogenic differentiation and inducing adipogenic differentiation. RNA-seq analysis revealed enrichment of the MAPK signaling pathway, suggesting its potential involvement in the regulation of adiponectin on SMSCs activity. Western blot analysis revealed that adiponectin activated ERK1/2 phosphorylation and inhibited p38 phosphorylation during the process of the inhibition on myogenic differentiation in chicken SMSCs. Furthermore, suppression of ERK1/2 signaling with U0126 or activation of p38 signaling with SSK1 reversed the downregulated expression of myogenic differentiation marker MyHC, MyOD1, and MyOG induced by adiponectin. These findings validated that adiponectin impeded myogenic differentiation through activation of ERK1/2 and inhibition of p38 signaling pathways. Additionally, activation of p38 signaling pathway reduced the increased percentage of EdU-positive cells induced by adiponectin. Collectively, these findings demonstrated that adiponectin impedes myogenic differentiation of SMSCs through activating ERK1/2 and inhibiting p38 signaling pathways, while promoting proliferation by inhibiting p38 signaling pathway.

Eicosapentaenoic acid-mediated activation of PGAM2 regulates skeletal muscle growth and development via the PI3K/AKT pathway

Eicosapentaenoic acid regulates glucose uptake in skeletal muscle and significantly affects whole-body energy metabolism. However, the underlying molecular mechanism remains unclear. Here we report that eicosapentaenoic acid activates phosphoglycerate mutase 2, which mediates the conversion of 2-phosphoglycerate into 3-phosphoglycerate. This enzyme plays a pivotal role in glycerol degradation, thereby facilitating the proliferation and differentiation of satellite cells in skeletal muscle. Interestingly, phosphoglycerate mutase 2 inhibits mitochondrial metabolism, promoting the formation of fast-type muscle fibers. Treatment with eicosapentaenoic acid and phosphoglycerate mutase 2 knockdown induced opposite transcriptomic changes, most of which were enriched in the PI3K-AKT signaling pathway. Phosphoglycerate mutase 2 activated the PI3K-AKT signaling pathway, which inhibited the phosphorylation of FOXO1, and, in turn, inhibited mitochondrial function and promoted the formation of fast-type muscle fibers. Our results suggest that eicosapentaenoic acid promotes skeletal muscle growth and regulates glucose metabolism by targeting phosphoglycerate mutase 2 and activating the PI3K/AKT signaling pathway.

Identification of different myofiber types in pigs muscles and construction of regulatory networks

BACKGROUND

Skeletal muscle is composed of muscle fibers with different physiological characteristics, which plays an important role in regulating skeletal muscle metabolism, movement and body homeostasis. The type of skeletal muscle fiber directly affects meat quality. However, the transcriptome and gene interactions between different types of muscle fibers are not well understood.

RESULTS

In this paper, we selected 180-days-old Large White pigs and found that longissimus dorsi (LD) muscle was dominated by fast-fermenting myofibrils and soleus (SOL) muscle was dominated by slow-oxidizing myofibrils by frozen sections and related mRNA and protein assays. Here, we selected LD muscle and SOL muscle for transcriptomic sequencing, and identified 312 differentially expressed mRNA (DEmRs), 30 differentially expressed miRNA (DEmiRs), 183 differentially expressed lncRNA (DElRs), and 3417 differentially expressed circRNA (DEcRs). The ceRNA network included ssc-miR-378, ssc-miR-378b-3p, ssc-miR-24-3p, XR_308817, XR_308823, SMIM8, MAVS and FOS as multiple core nodes that play important roles in muscle development. Moreover, we found that different members of the miR-10 family expressed differently in oxidized and glycolytic muscle fibers, among which miR-10a-5p was highly expressed in glycolytic muscle fibers (LD) and could target MYBPH gene mRNA. Therefore, we speculate that miR-10a-5p may be involved in the transformation of muscle fiber types by targeting the MYHBP gene. In addition, PPI analysis of differentially expressed mRNA genes showed that ACTC1, ACTG2 and ACTN2 gene had the highest node degree, suggesting that this gene may play a key role in the regulatory network of muscle fiber type determination.

CONCLUSIONS

We can conclude that these genes play a key role in regulating muscle fiber type transformation. Our study provides transcriptomic profiles and ceRNA interaction networks for different muscle fiber types in pigs, providing reference for the transformation of pig muscle fiber types and the improvement of meat quality.

miR-103-3p Regulates the Proliferation and Differentiation of C2C12 Myoblasts by Targeting BTG2

Skeletal muscle, a vital and intricate organ, plays a pivotal role in maintaining overall body metabolism, facilitating movement, and supporting normal daily activities. An accumulating body of evidence suggests that microRNA (miRNA) holds a crucial role in orchestrating skeletal muscle growth. Therefore, the primary aim of this study was to investigate the influence of miR-103-3p on myogenesis. In our study, the overexpression of miR-103-3p was found to stimulate proliferation while suppressing differentiation in C2C12 myoblasts. Conversely, the inhibition of miR-103-3p expression yielded contrasting effects. Through bioinformatics analysis, potential binding sites of miR-103-3p with the 3'UTR region of BTG anti-proliferative factor 2 (BTG2) were predicted. Subsequently, dual luciferase assays conclusively demonstrated BTG2 as the direct target gene of miR-103-3p. Further investigation into the role of BTG2 in C2C12 myoblasts unveiled that its overexpression impeded proliferation and encouraged differentiation in these cells. Notably, co-transfection experiments showcased that the overexpression of BTG2 could counteract the effects induced by miR-103-3p. In summary, our findings elucidate that miR-103-3p promotes proliferation while inhibiting differentiation in C2C12 myoblasts by targeting BTG2.