IFRD2, a target of miR-2400, regulates myogenic differentiation of bovine skeletal muscle satellite cells via decreased phosphorylation of ERK1/2 proteins.

The proliferation and differentiation of skeletal muscle satellite cells is a complex physiological process involving various transcription factors and small RNA molecules. This study aimed to understand the regulatory mechanisms underlying these processes, focusing on interferon-related development factor 2 (IFRD2) as a target gene of miRNA-2400 in bovine skeletal MuSCs (MuSCs). IFRD2 was identified as a target gene of miRNA-2400 involved in regulating the proliferation and differentiation of bovine skeletal MuSCs. Our results indicate that miR-2400 can target binding the 3'UTR of IFRD2 and inhibit its translation. mRNA and protein expression levels of IFRD2 increased significantly with increasing days of differentiation. Moreover, overexpression of the IFRD2 gene inhibited proliferation and promoted differentiation of bovine MuSCs. Conversely, the knockdown of the gene had the opposite effect. Overexpression of IFRD2 resulted in the inhibition of ERK1/2 phosphorylation levels in bovine MuSCs, which in turn promoted differentiation. In summary, IFRD2, as a target gene of miR-2400, crucially affects bovine skeletal muscle proliferation and differentiation by precisely regulating ERK1/2 phosphorylation.

[Effects of transcription factor SIX2 gene on the proliferation of bovine skeletal muscle satellite cells].

Objective: To investigate the effect of SIX2 gene on the proliferation of bovine skeletal muscle satellite cells. Methods: Bovine skeletal muscle satellite cells were used as experimental materials, and the expression of SIX2 gene in bovine skeletal muscle satellite cells was detected by real-time quantitative PCR at 24 h, 48 h, and 72 h of proliferation. The SIX2 gene overexpression vector was constructed by homologous recombination. The SIX2 gene overexpression plasmid and the control empty plasmid were transfected into bovine skeletal muscle satellite cells, and each group had three complex Wells. The cell viability was detected by MTT assay at 24 h, 48 h and 72 h after transfection. At 48 h after transfection, the cell cycle was detected by flow cytometry, and the expressions of cell proliferation marker genes were detected by real-time quantitative PCR (qRT-PCR) and Western blot. Results: With the proliferation of bovine skeletal muscle satellite cells, the expression of SIX2 mRNA was increased. Compared with the control group, the expressions of SIX2 mRNA and protein in the SIX2 gene overexpression plasmid group were increased by 18 and 2.6 times, respectively (P＜0.01). The cell viability of the SIX2 gene overexpression plasmid group was increased (P＜0.01), the proportion of G1 cells was decreased by 24.6%, and the proportion of S phase and G2 phase cells was increased by 20.3% and 4.31%, respectively (P＜0.01). The mRNA and protein expressions of Pax7 gene were increased by 15.84 and 1.22 times, respectively, and the mRNA and protein expressions of proliferation marker genes PCNA and CCNB1 were increased by 4.82, 2.23,1.55 and 1.46 times, respectively (P＜0.01). Conclusion: Overexpression of SIX2 gene promotes the proliferation of bovine skeletal muscle satellite cells.