Quantitative Proteomics Reveals Changes in Vero Cells in Response to Porcine Epidemic Diarrhea Virus

Outbreaks of porcine epidemic diarrhea
virus (PEDV) have caused
significant lethality rates in neonatal piglets, which pose a serious
threat to the swine industry worldwide. Available commercial vaccines
fail to protect against the emergence of high virulence of PEDV variants.
Therefore, the endemic state of the PEDV infection in suckling piglets
highlights the urgent need for uncovering the molecular determinants
of the disease pathogenesis. In this study, stable isotope labeling
by amino acids in cell culture (SILAC), combined with high-performance
liquid chromatography/tandem mass spectrometry was performed to determine
proteomic differences between PEDV-infected and mock-infected Vero
cells at 18 h postinfection. The SILAC-based approach identified 4508
host-cell proteins, of which 120 were significantly up-regulated and
103 were significantly down-regulated at ≥95% confidence. Alterations
in the expression of selected proteins were verified by Western blot.
Several signaling metabolic pathways including mevalonate pathway
I and the superpathway of cholesterol biosynthesis were triggered
by the infection of the highly virulent strain and are linked to host
innate immunity. 25-HC, an inhibitor of the mevalonate pathway, exhibited
potent antiviral activity against PEDV infection. Meanwhile, the cell-cycle-related
functions were significantly regulated, which may likely be responsible
for the viral replication and pathogenicity of PEDV.