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. Commercial vaccines available fail to protect against the emergence of high virulence of PEDV variants. Therefore, the endemic state of 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 (HPLC)/tandem mass spectrometry, was performed to determine proteomic differences between PEDV-infected and mock-infected Vero cells at 18 h post-infection. 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 superpathway of cholesterol biosynthesis were triggered by the infection of the highly virulent strain, which are linked to host innate immunity. 25-HC, an inhibitor of the mevalonate pathway, exhibited potent antiviral activity against PEDV infection. Meanwhile, cell cycle related function were significantly regulated, which may be likely responsible for viral replication and pathogenicity of PEDV.