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Expression profiles of seven channel catfish antimicrobial peptides in response to Edwardsiella ictaluri infection
Author(s) -
Pridgeon J W,
Mu X,
Klesius P H
Publication year - 2012
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/j.1365-2761.2011.01343.x
Subject(s) - edwardsiella ictaluri , downregulation and upregulation , catfish , biology , hepcidin , microbiology and biotechnology , cathepsin l , ictalurus , antimicrobial peptides , immunology , antimicrobial , cathepsin , gene , inflammation , biochemistry , enzyme , fishery , fish <actinopterygii>
Using quantitative polymerase chain reaction (QPCR), the relative transcriptional levels of seven channel catfish antimicrobial peptide (AMP) genes (NK‐lysin type 1, NK‐lysin type 2, NK‐lysin type 3, bactericidal permeability‐increasing protein, cathepsin D, hepcidin and liver‐expressed AMP 2) in response to Edwardsiella ictaluri infection were determined. None of the AMP genes tested was significantly upregulated at 2 h post‐infection. Hepcidin was the only one that was significantly ( P < 0.05) upregulated at 4, 6 and 12 h post‐infection. At 24 and 48 h post‐infection, four AMPs (hepcidin, NK‐lysin type 1, NK‐lysin type 3 and cathepsin D) were significantly ( P <0.05) upregulated. Among all the AMPs that were significantly upregulated at different time points, hepcidin at 4, 6 and 12 h post‐infection was upregulated the most. When catfish were injected with different doses of E. ictaluri , all lethal doses were able to induce significant ( P <0.05) upregulation of hepcidin in the posterior kidney, whereas sublethal doses failed to induce any significant upregulation of hepcidin. In vitro growth studies revealed that the presence of synthetic hepcidin peptide at a concentration of 16 μ m or higher significantly inhibited the cell proliferation of E. ictaluri . Taken together, our results suggest that hepcidin might play an important role in the channel catfish defence against E. ictaluri infection.