Transcriptome profiling and differential expression analysis of the immune-related genes during the acute phase of infection with Mycobacterium marinum in the goldfish (Carassius auratus L.)

Abstract

Goldfish (Carassius auratus L.) have been used as a model organism to study innate immune system and host-pathogen interactions. Mycobacterium marinum is a Gram-positive bacterium that has been shown to infect many fish species. To increase knowledge of the molecular mechanisms of the host defense against M. marinum, we conducted transcriptome analysis of spleen in goldfish 24 h post-infection via Illumina sequencing. The de novo assembly resulted in the identification of 83,674 unigenes, with 69,050 (82.52.9%) successfully annotated in public databases (GO, KEGG, COG, NR, SwissProt and Pfam). Comparison of gene expression profiles between M. marinum-stimulated fish and PBS-injected fish (sham control) revealed 4200 differentially expressed genes (DEGs), with 2211 up-regulated and 1989 down-regulated. The DEGs were enriched in multiple immune-related pathways such as Toll-like receptor signaling pathway, NOD-like receptor signaling pathway, NF-κB signaling pathway, Jak-STAT signaling pathway, and cytokine-cytokine receptor interaction pathway. The data obtained in the present study offers valuable information for acute immune response of goldfish challenged with M. marinum, which will facilitate further investigations on strategies against M. marinum infection in teleosts.