Transcriptome analysis reveals heat shock protein 70 (HSP70) induced by tembusu virus infection is associated with immune responses

The outbreak and prevalence of tembusu virus (TMUV) endanger the breeding industry of waterfowls. However, little is known about the molecular mechanism underlying TMUV infection. It was reported that heat shock protein 70 (HSP70) was a positive regulator of the infection of TMUV. In order to study the interactions between HSP70 and host immune response to TMUV infection, TMUV-infected cells with or without HSP70 inhibitor were harvested and subjected to deep sequencing to identify genes differentially expressed. We found 43 differentially expressed genes (DEGs) in HSP70 inhibitor-treated and mock-treated TMUV-infected DF-1 cells. Of these DEGs, 39 genes were down-regulated significantly. Gene Ontology analysis suggested that the DEGs were mainly involved in biological process, cellular component and molecular function. Kyoto Encyclopedia of Genes and Genomes analysis showed that the DEGs mainly related to the activation of innate immune response, including RIG-I-like receptor, toll-like receptor and NF-κB signaling pathway. Also, 12 down-regulated immune-related DEGs were selected for confirmation by reverse transcription quantitative real-time PCR verification, all these genes showed consistent expression between the result of reverse transcription quantitative real-time PCR and transcriptomic sequencing. These results revealed the important role of HSP70 in facilitating the innate immune response induced by TMUV infection. This is first to access the role of HSP70 in host response to TMUV infection, which provides a basis for further study of the pathogenesis of TMUV and contributes to the elucidation of TMUV-host interactions.