Establishment of a myostatin gene-knockout C2C12 cell line and evaluation of related microRNA expression

The strategy of blocking myostatin (MSTN) signal transduction has long been regarded as a promising approach in the treatment of patients with muscle loss. However, individuals taking blocking agents often encounter issues such as lack of strength, fatigue, and poor muscle proliferation due to muscle hypertrophy and the involvement of multiple receptors. To address these challenges, a series of experiments were conducted on a C2C12 cell line in this study. First, the pX601-SaCas9-sgRNA/puro vector carrying a Cas9-encoded gene was constructed and subsequently used to produce Mstn-knockout (Mstn-KO) C2C12 cell lines. The expression level of the MSTN protein and the growth characteristics of the cell lines were verified. Moreover, the expression of muscle growth-related microRNAs in the cell lines was analyzed through real-time polymerase chain reaction (PCR). The results indicate that we have successfully established a method for constructing Mstn-KO cell lines with stable passage. No expression of the MSTN protein and strong cell proliferation were observed in the cell lines. Moreover, real-time PCR experiments showed that the expression levels of miR-1, miR-431, miR-206, and miR-133a were significantly increased (P < 0.01), the expression level of miR-23a was significantly increased (P < 0.05), and the expression level of miR-486 was significantly decreased (P < 0.05). These findings indicate that multiple miRNAs are closely associated with MSTN regulation. This study lays the foundation for further investigation into the effects of the Mstn gene on the physiological function of myoblasts and the development of drugs that block the MSTN signaling pathway.