Altered Proteomic Profile of Exosomes Secreted from Vero Cells Infected with Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea virus (PEDV) infection causes severe diarrhea in pigs and can be fatal in newborn piglets. Exosomes are extracellular vesicles secreted by cells that transfer biologically active proteins, lipids, and RNA to neighboring or distant cells. Herein, the morphology, particle size, and secretion of exosomes derived from a control and PEDV-infected group are examined, followed by a proteomic analysis of the exosomes. The results show that the exosomes secreted from the Vero cells had a typical cup-shaped structure. The average particle size of the exosomes from the PEDV-infected group was 112.4 nm, whereas that from the control group was 150.8 nm. The exosome density analysis and characteristic protein determination revealed that the content of exosomes in the PEDV-infected group was significantly higher than that in the control group. The quantitative proteomics assays revealed 544 differentially expressed proteins (DEPs) in the PEDV-infected group's exosomes compared with those in the controls, with 236 upregulated and 308 downregulated proteins. The DEPs were closely associated with cellular regulatory pathways, such as the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, extracellular matrix-receptor interaction, focal adhesion, and cytoskeletal regulation. These findings provide the basis for further investigation of the pathogenic mechanisms of PEDV and the discovery of novel antiviral targets.