Transcriptome analysis reveals the relationship between Spring viremia of carp N protein-induced endoplasmic reticulum stress in Epithelioma papulosum cyprinid (EPC) cells and apoptosis and autophagy

Spring viremia of carp virus(SVCV) is one of the important pathogens of viral infectious diseases in fish, which brings severe economic losses to the aquaculture industry and is familiar and challenging to control viral disease in aquaculture. Currently, studies have shown that SVCV can induce endoplasmic reticulum stress, whereas the relationship between whether the most abundant protein of SVCV-N, can induce endoplasmic reticulum stress, autophagy and apoptosis has not been reported. In this study, the SVCV-N protein was overexpressed in EPC cells. According to transcriptome analysis of gene changes in EPC cells, there were 2290 differentially expressed genes, 1137 up-regulated and 1153 down-regulated genes compared to controls transfected with the empty vector pCS 2 + 8CmCherry. After gene ontology (GO) analysis, they were classified into three categories: biological processes, molecular functions and cellular components. KEGG enrichment analysis showed that 722 differentially expressed genes were enriched in 190 KEGG pathways, most of them were enriched in endoplasmic reticulum processing. Western blotting showed that GRP78, Beclin1 and Lc3-II/Lc3- I protein expression was increased, and p62 protein expression was decreased. Flow cytometry showed an increased rate of apoptosis. Activation inhibition experiments showed that activation of endoplasmic reticulum stress expression by SVCV-N protein promotes autophagy and apoptosis, and vice versa. The qRT-PCR results are consistent with the RNA-Seq, indicating that the transcriptome sequencing data are reliable. This study provides preliminary insight into the pathogenic mechanism of SVCV-N infection and provides data to reveal the mechanism.