Pleomorphic adenoma gene 1 (PLAG1) promotes proliferation and inhibits apoptosis of bovine primary myoblasts through the PI3K-Akt signaling pathway

PLAG1 is important for growth and development; however, its role in bovine muscle development is unclear. Our study demonstrates that PLAG1 promotes proliferation and inhibits apoptosis of bovine primary myoblasts through the PI3K-Akt signaling pathway. Pleomorphic adenoma gene 1 (PLAG1) is a transcription factor involved in various cellular processes in organismal growth and development. However, its role in muscle function is unclear. This work investigated the roles of PLAG1 in muscle development and explored its regulatory mechanisms. The PLAG1 was proved to promote the proliferation of bovine primary myoblasts using the cell counting kit 8 (CCK-8) assay (P < 0.001), 5-ethynyl-2'-deoxyuridine (EdU) proliferation assay (P = 0.005), quantitative real-time polymerase chain reaction (qRT-PCR) (P = 0.028), western blot, and flow cytometry (P < 0.05), and to inhibit apoptosis of bovine primary myoblasts using qRT-PCR (P = 0.038), western blot, and flow cytometry (P < 0.001). Chromatin immunoprecipitation sequencing (ChIP-seq) and western blot showed PLAG1 upregulated phosphorylated (p)-PI3K, PI3K, p-Akt, Akt, Cyclin D1, and CDK2 and inhibited the expression of p21 and p27 to enhance myoblast proliferation, and increased expression of Bcl-2, and Bcl-xL to inhibit apoptosis. Additionally, PLAG1 was identified as a target of miR-1 using dual-luciferase assay (P < 0.001), qRT-PCR (P < 0.001), and western blot. Furthermore, miR-1 might be a potential mediator of the positive feedback regulation relationship between PLAG1 and the PI3K-Akt signaling pathway. Lay Summary Pleomorphic adenoma gene 1 (PLAG1) is a critical candidate gene that affects bovine stature and height. Past studies have focused on correlations between PLAG1 and quantitative traits. However, few studies have focused on studying the function of PLAG1 at the cellular level. Here, we investigated the effects of PLAG1 on bovine primary myoblasts and found it promoted proliferation and inhibited the apoptosis of bovine primary myoblasts. In addition, our study demonstrated that the effects of PLAG1 on myoblast proliferation and apoptosis were through the PI3K-Akt signaling pathway. Further study suggested that there was a potential positive feedback regulation between PLAG1 and PI3K-Akt, and miR-1 acted as a key mediator. Our study provided a theoretical basis for further exploration.