Cellular proteomic analysis of porcine circovirus type 2 and classical swine fever virus coinfection in porcine kidney-15 cells using isobaric tags for relative and absolute quantitation-coupled LC-MS/MS.

Viral coinfection or superinfection in host has caused public health concern and huge economic losses of farming industry. The influence of viral coinfection on cellular protein abundance is essential for viral pathogenesis. Based on a coinfection model for porcine circovirus type 2 (PCV2) and classical swine fever virus (CSFV) developed previously by our laboratory, isobaric tags for relative and absolute quantitation (iTRAQ)-coupled LC-MS/MS proteomic profiling was performed to explore the host cell responses to PCV2-CSFV coinfection. Totally, 3932 proteins were identified in three independent mass spectrometry analyses. Compared with uninfected cells, 304 proteins increased (fold change >1.2) and 198 decreased (fold change <0.833) their abundance in PCV2-infected cells (p < 0.05), 60 and 61 were more and less abundant in CSFV-infected cells, and 196 and 158 were more and less abundant, respectively in cells coinfected with PCV2 and CSFV. Representative differentially abundant proteins were validated by quantitative real-time PCR, Western blotting and confocal laser scanning microscopy. Bioinformatic analyses confirmed the dominant role of PCV2, and indicated that mitochondrial dysfunction, nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress response and apoptosis signaling pathways might be the specifical targets during PCV2-CSFV coinfection.