Transcriptome analysis of PK-15 cells expressing CSFV NS4A.

BACKGROUND: Classical swine fever (CSF) is a severe disease of pigs that results in huge economic losses worldwide and is caused by classical swine fever virus (CSFV). CSFV nonstructural protein 4 A (NS4A) plays a crucial role in infectious CSFV particle formation. However, the function of NS4A during CSFV infection is not well understood.  RESULTS: In this study, we used RNA-seq to investigate the functional role of CSFV NS4A in PK-15 cells. A total of 3893 differentially expressed genes (DEGs) were identified in PK-15 cells expressing NS4A compared to cells expressing the empty vector (NC). Twelve DEGs were selected and further verified by RT‒qPCR. GO and KEGG enrichment analyses revealed that these DEGs were associated with multiple biological functions, including cell adhesion, apoptosis, host defence response, the inflammatory response, the immune response, and autophagy. Interestingly, some genes associated with host immune defence and inflammatory response were downregulated, and some genes associated with host apoptosis and autophagy were upregulated. CONCLUSION: CSFV NS4A inhibits the innate immune response, and suppresses the expression of important genes associated with defence response to viruses and inflammatory response, and regulates cell adhesion, apoptosis and autophagy.