Transcriptome and Proteomic Analysis Reveals Up-Regulation of Innate Immunity-Related Genes Expression in Caprine Herpesvirus 1 Infected Madin Darby Bovine Kidney Cells

Caprine herpesvirus 1 (CpHV-1) is a member of the alpha subfamily of herpesviruses, which is responsible for genital lesions and latent infections in goat populations worldwide. In this study, for the first time, the transcriptome and proteomics of CpHV-1 infected Madin Darby bovine kidney (MDBK) cells were explored using RNA-Sequencing (RNA-Seq) and isobaric tags for relative and absolute quantitation-liquid chromatography tandem mass spectrometry (iTRAQ-LC-MS/MS) technology, respectively. RNA-Seq analysis revealed 81 up-regulated and 19 down-regulated differentially expressed genes (DEGs) between infected and mock-infected MDBK cells. Bioinformatics analysis revealed that most of these DEGs were mainly involved in the innate immune response, especially the interferon stimulated genes (ISGs). Gene Ontology (GO) enrichment analysis results indicated that the identified DEGs were significantly mainly enriched for response to virus, defense response to virus, response to biotic stimulus and regulation of innate immune response. Viral carcinogenesis, the RIG-I-like receptor signaling pathway, the cytosolic DNA-sensing pathway and pathways associated with several viral infections were found to be significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. Eleven selected DEGs (Mx1, RSAD2, IFIT1, IFIT2, IFIT5, IFIH1, IFITM3, IRF7, IRF9, OAS1X and OAS1Y) associated with immune responses were selected, and they exhibited a concordant direction both in RNA-Seq and quantitative real-time RT-PCR analysis. Proteomic analysis also showed significant up-regulation of innate immunity-related proteins. GO analysis showed that the differentially expressed proteins were mostly enriched in defense response and response to virus, and the pathways associated with viral infection were enriched under KEGG analysis. Protein-protein interaction network analysis indicated most of the DEGs related to innate immune responses, as DDX58(RIG-I), IFIH1(MDA5), IRF7, Mx1, RSAD2, OAS1 and IFIT1, were located in the core of the network and highly connected with other DGEs. Our findings support the notion that CpHV-1 infection induced the transcription and protein expression alterations of a series of genes related to host innate immune response, which helps to elucidate the resistance of host cells to viral infection and to clarify the pathogenesis of CpHV-1.

Automated summary

Analysis of CpHV-1 infected MDBK cells using RNA-Seq and iTRAQ-LC-MS/MS revealed differentially expressed genes mainly involved in the host innate immune response. The up-regulated DEGs were enriched in pathways related to viral infection, highlighting the importance of host immune response in CpHV-1 pathogenesis.