PLAG1 Promotes Proliferation and Differentiation of Sujiang Pig MuSCs: Insights from Whole-Transcriptome and ceRNA Network Analyses

Skeletal muscle satellite cells (MuSCs) are essential for muscle growth and development, but their regulatory mechanisms remain unclear. This study aimed to characterize the expression pattern of pleomorphic adenoma gene 1 (PLAG1), determine its effects on MuSC proliferation and differentiation, and explore its potential regulatory mechanisms through integrated transcriptomic and ceRNA analyses in Sujiang pig MuSCs. Results showed that PLAG1 was widely expressed in multiple porcine tissues and was significantly upregulated during MuSC differentiation. PLAG1 overexpression promoted MuSC proliferation and differentiation, whereas PLAG1 knockdown produced the opposite effects. Whole-transcriptome sequencing following PLAG1 knockdown identified 432 differentially expressed mRNAs, 70 miRNAs, 163 lncRNAs, and 150 circRNAs. Enrichment analysis revealed that differentially expressed mRNAs were mainly associated with cell cycle regulation, DNA replication, and the p53 signaling pathway. Western blot analysis further showed that PLAG1 knockdown reduced CDK1 and PCNA protein levels. ceRNA network analysis revealed potential regulatory associations among differentially expressed lncRNAs, circRNAs, miRNAs, and mRNAs, and the expression changes in selected differentially expressed RNAs were further validated by qRT-PCR. Collectively, these findings indicate that PLAG1 promotes MuSC proliferation and differentiation and may be associated with cell cycle-related gene expression changes and potential non-coding RNA regulatory networks in porcine MuSCs.