Abstract
Infections with bovine viral diarrhea virus (BVDV) contribute significantly to health-related economic losses in the beef and dairy industries and are widespread throughout the world. Severe acute BVDV infection is characterized by a gastrointestinal (GI) inflammatory response. The mechanism of inflammatory lesions caused by BVDV remains unknown. The interstitial cells of Cajal (ICC) network plays a pivotal role as a pacemaker in the generation of electrical slow waves for GI motility, and it is crucial for the reception of regulatory inputs from the enteric nervous system. The present study investigated whether ICC were a good model for studying GI inflammatory lesions caused by BVDV infection. Primary ICC were isolated from the duodenum of Merino sheep. The presence of BVDV was detected in ICC grown for five passages after BVDV infection, indicating that BVDV successfully replicated in ICC. After infection with BVDV strain TC, the cell proliferation proceeded slowly or declined. Morphological changes, including swelling, dissolution, and formation of vacuoles in the ICC were observed, indicating quantitative, morphological and functional changes in the cells. RNA sequencing (RNA-Seq) was performed to investigate differentially expressed genes (DEGs) in BVDV-infected ICC and explore the molecular mechanism of underlying quantitative, morphological and functional changes of ICC. Eight hundred six genes were differentially expressed after BVDV infection, of which 538 genes were upregulated and 268 genes were downregulated. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the 806 DEGs were significantly enriched in 27 pathways, including cytokine-cytokine receptor interaction, interleukin (IL)-17 signaling and mitogen-activated protein kinase (MAPK) signaling pathways. The DEGs and raw files of high-throughput sequencing of this study were submitted to the NCBI Gene Expression Omnibus (GEO) database (accession number GSE122344). Finally, 21 DEGs were randomly selected, and the relative repression levels of these genes were tested using the quantitative real-time PCR (qRT-PCR) to validate the RNA-Seq results. The results showed that the related expression levels of 21 DEGs were similar to RNA-Seq. This study is the first to establish a new infection model for investigating GI inflammatory lesions induced by BVDV infection. RNA-Seq-based transcriptomic profiling can provide a basis for study on BVDV-associated inflammatory lesions.