Differential transcriptome analysis of zebrafish (Danio rerio) larvae challenged by Vibrio parahaemolyticus.

Zebrafish embryo and larva represent a useful in vivo model for identification of host innate immune responses to bacterial infection. Vibrio parahaemolyticus is a typical zoonotic pathogen worldwide that causes acute gastroenteritis in humans and vibriosis in fishes. However, the mechanism of the innate immune response in the zebrafish larvae infected by V. parahaemolyticus has not been clear. We analysed the transcriptomic profile of 3 days post-fertilization (dpf) zebrafish larvae immersed in V. parahaemolyticus 13 (Vp13) strain suspension for 2 hr. A total of 602 differentially expressed genes (DEGs) were identified in the infection group, of which 175 (29.07%) genes were upregulated and 427 (70.93%) genes were downregulated. These altered genes encoded complement and coagulation cascades, chemokine, TNF signalling pathway, NF-κB signalling pathway and JAK-STAT signalling pathway. Some significant DEGs, such as mmp13, cxcr4a, ccl20, hsp70, gngt, serpina1l, il8, cofilin and il11, were subjected to quantitative gene expression analysis, and the results were consistent with those of the transcriptome profile. These results clearly demonstrated that exposure to V. parahaemolyticus for 2 hr could activate innate immune response in 3dpf larvae by altered expression of downstream signalling pathway genes of pattern recognition receptors (PRRs). Our results also provide a useful reference for future analysis of signal transduction pathways and pathogenesis mechanisms underlying the systemic innate immune response to the external bacteria of V. parahaemolyticus.