Spring viraemia of carp virus infection induces hypoxia response in zebrafish by stabilizing hif1a

The hypoxia signaling pathway controls hypoxia adaptation and tolerance of organisms, which is regulated by multiple mechanisms. Viral infection elicits various pathophysiological responses in the host. However, whether viral infection can affect the hypoxia response is still largely unknown. In this study, we found that Spring viraemia of carp virus (SVCV) infection in zebrafish caused symptoms similar to those in zebrafish under hypoxic conditions. Further assays indicated that SVCV infection activated the hypoxia signaling pathway in zebrafish. In addition, SVCV infection caused increased glycolysis and ROS levels in cells. Mechanistically, SVCV-G protein interacted with hif1a-a/b and attenuated their K48-linked polyubiquitination, leading to their stabilization and subsequent enhancement of target gene expression. Moreover, treatment with the HIF1a-specific inhibitor PX478 enhanced the antiviral ability against SVCV infection in zebrafish and zebrafish cells. This study reveals a relationship between SVCV infection and the hypoxia signaling pathway in fish, and provides a strategy for reducing the damage of viral disease in the aquaculture industry. Overall design: Zebrafish larvae were placed in disposable cell culture dishes (60 mm in diameter) containing 4 mL of egg water, and 2 mL of SVCV (~5.0×107 TCID50/mL) was added into each dish. Whole RNA of zebrafish larvae (3 dpf) infected with or without SVCV were purified using RNeasy Mini Kit (QIAGEN NO. 74104). Three biological replicates were used for each sample. The transcriptome library for sequencing was generated using NEBNext Ultra RNA Library Prep Kit for Illumina (NEB, USA, #E7530L) following manufacturer's protocol In order to ensure the quality of information analysis, the software fastp was used to remove the splice sequences, filter the low quality, N bases (indicating that the base information could not be determined), and obtain high quality clean data. clean data, and the number of bases and sequences of the clean data were counted. At the same time, GC, Q20, Q30 content of the clean data were calculated (GenePlus, Beijing, China). Heatmaps were generated using Multi Experiment Viewer (MeV) software. Gene Ontology (GO) enrichment analyses for the differentially expressed genes (DEGs) were performed using the cluster Profiler version 3.8.