Proteome analysis of differential protein expression in porcine alveolar macrophages regulated by porcine reproductive and respiratory syndrome virus nsp1 beta protein

摘要

Porcine reproductive and respiratory syndrome virus (PRRSV), an acute infectious disease agent in swine, causes enormous economic losses to the global swine industry. PRRSV nonstructural protein 1 beta (nsp1 beta) plays a critical role in viral subgenomic mRNA synthesis and host immune regulation. However, the global changes of cellular gene expression in natural target cells regulated by the nsp1 beta have not yet been identified. Here, isobaric tags for relative and absolute quantification (iTRAQ) labeling coupled with liquid chromatography-tandem mass spectrometry were used to quantitatively identify cellular proteins in porcine alveolar macrophage (PAM) 3D4/21 cells transduced with recombinant lentivirus expressing PRRSV nsp1 beta that are differentially expressed compared with PAM 3D4/21 cells transduced with recombinant lentivirus expressing GFP. Of the 425 cellular proteins detected as differentially expressed, 186 were upregulated and 239 were downregulated. Based on the identities of the differentially expressed cellular proteins and the essential role of nsp1 beta in interferon (IFN) activation and inflammatory factor antagonism during PRRSV infection, we propose a potential mechanism in which nsp1 beta inhibits IFN induction and nuclear factor kappa B (NF-kappa B) signaling pathways. Our results suggest that mitochondrial antiviral signaling (MAVS) protein and translocases of outer membrane complex 70 (TOM70), involved in type I IFN induction, were downregulated, while protein phosphatase 1A (PPM1A), related to the inhibition of NF-kappa B pathway activation, was upregulated in nsp1 beta-overexpressed PAM 3D4/21 cells. These data provide valuable information for better understanding the potential biological function of nsp1 beta during PRRSV infection and the mechanism of virus escape from host immune surveillance of viral replication.