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Comprehensive gene expression profiling in Japanese flounder kidney after injection with two different
Hidehiro Kondo1, Yuriko Kawana1, Yoshiaki Suzuki1
1Laboratory of Genome Science, Graduate School of Tokyo University of Marine Science and Technology, Minato, Tokyo, Japan.
Abstract:
Pathogenic bacteria possess some components, that are recognized by the host immune receptors. Different components are recognized by distinct receptors, and thus it is speculated that these components may regulate different gene sets. To investigate the gene expression profiles regulated by different bacterial components in Japanese flounder Paralichthys olivaceus, Japanese flounder were intraperitoneally injected with formalin-killed bacterial cells (FKC) of Edwardsiella tarda and Streptococcus iniae. The numbers of differentially regulated genes were much larger in the fish injected with E. tarda than those with S. iniae. Comprehensive gene expression profiling showed that almost all of the genes differentially regulated by injections of E. tarda FKC were also differentially regulated by injections of S. iniae FKC. mRNA levels of inflammatory cytokines, including interleukin (IL)-1β, IL-8, interferon γ and tumor necrosis factor were upregulated in both of the injected groups. Each of these mRNAs except for IL-8 mRNA were also much higher in the E. tarda FKC injected group than in the S. iniae FKC injected group. Furthermore, mRNA levels of IL-6 were strongly up-regulated in the E. tarda FKC injected group. The E. tarda FKC might induce higher inflammatory responses than S. iniae FKC.
Insights
Edwardsiella tarda formalin-killed bacterial cells (FKC) induced a stronger immune response in Japanese flounder than Streptococcus iniae FKC. This suggests different bacterial components can regulate distinct gene sets and inflammatory pathways.
Area of Science:
- Immunology
- Fish immunology
- Molecular biology
Background:
- Pathogenic bacteria possess components recognized by host immune receptors, potentially regulating distinct gene sets.
- Understanding these interactions is crucial for fish health and disease management in aquaculture.
Purpose of the Study:
- To investigate gene expression profiles regulated by different bacterial components in Japanese flounder (Paralichthys olivaceus).
- To compare the immune response elicited by Edwardsiella tarda and Streptococcus iniae formalin-killed bacterial cells (FKC).
Main Methods:
- Japanese flounder were intraperitoneally injected with formalin-killed bacterial cells (FKC) of E. tarda and S. iniae.
- Comprehensive gene expression profiling was performed to analyze differentially regulated genes.
- mRNA levels of inflammatory cytokines were quantified using quantitative PCR.
Main Results:
- A larger number of genes were differentially regulated by E. tarda FKC compared to S. iniae FKC.
- Almost all genes regulated by E. tarda FKC were also regulated by S. iniae FKC.
- mRNA levels of inflammatory cytokines (IL-1β, IL-8, IFN-γ, TNF) were upregulated in both groups, with higher levels for most in the E. tarda group. IL-6 was strongly upregulated by E. tarda FKC.
Conclusions:
- E. tarda FKC may induce a higher inflammatory response in Japanese flounder than S. iniae FKC.
- Different bacterial components can elicit distinct immune responses and regulate specific gene expression patterns.
- This study provides insights into the molecular mechanisms of immune recognition and response in fish.
