Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that infect pigs’ intestinal epithelial cells, causing high morbidity and mortality. Due to the rapid mutation of PEDV, vaccine efficacy is uncertain, prompting exploration of alternative treatments. Nanobodies, also known as variable heavy chain domains of heavy chain-only antibodies (VHHs), offer significant potential in biomedical applications due to their small size and high specificity. In this study, yeast two-hybrid technology was employed to screen for eight specific VHH sequences targeting the PEDV S protein from a synthetically constructed nanobody yeast library. The VHH genes were then cloned into expression plasmids for recombinant protein production, and the resulting VHHs (termed PEDV S-VHHs) were purified. Indirect immunofluorescence assay (IFA) and Western blotting analysis confirmed that these VHHs specifically bind to both PEDV and its S protein. Neutralization assays demonstrated that seven PEDV S-VHHs exhibited potent neutralizing activity against PEDV. Additionally, a combination of these seven antibodies showed enhanced antiviral effects. Preliminary predictions were also made regarding the binding sites between these VHHs and PEDV. The PEDV S-VHHs described in this study hold potential as candidates for the prevention and treatment of PEDV infection.

Sujiang pigs, a high-quality local Chinese breed, represent a valuable model for investigating muscle development and improving meat production through genetic selection. Skeletal muscle satellite cells (MuSCs) are essential regulators of muscle growth, with differentiation tightly controlled by specific genes and signaling pathways. In this study, MuSCs were isolated from the gastrocnemius muscle and subjected to mRNA sequencing during proliferation (GM) and differentiation stages (DM1, DM2, and DM4, collectively referred to as DM). A total of 2790 differentially expressed genes (DEGs) were identified, including 1551 upregulated and 1239 downregulated genes. Time-series analysis revealed 16 significant expression patterns. These DEGs were primarily associated with muscle development and differentiation and were enriched in Wnt, PI3K–Akt, JAK–STAT, p53, Hippo, and Apelin signaling pathways. Among them, phosphoribosyl transferase domain containing 1 (PRTFDC1) exhibited pronounced downregulation during differentiation. Functional validation demonstrated that PRTFDC1 overexpression promoted myotube formation and upregulated MYOD1, MYOG, and MYH1 expression, whereas knockdown significantly inhibited differentiation. Furthermore, PRTFDC1 enhanced phosphorylation of key proteins in the cGAS–STING signaling pathway. Collectively, this study elucidates the temporal transcriptional regulation of MuSC differentiation in Sujiang pigs and identifies PRTFDC1 as a novel regulatory factor, providing a molecular foundation for breeding strategies and meat quality improvement.

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.