Immunomodulatory function of antimicrobial peptide EC-Hepcidin1 modulates the induction of inflammatory gene expression in primary cells of Caspian Trout (Salmo trutta caspius Kessler, 1877)

Hepcidins, a group of antimicrobial peptides (AMPs), play a key role in the innate immune system of fishes and act against different pathogens. In this study, antimicrobial and immune-inflammatory activity of a synthetic EC-hepcidin1, previously identified from orange-spotted grouper, were evaluated. EC-hepcidin1 showed weak activity against the zoonotic fish pathogen Streptococcus iniae (MIC 100 mu g mL(-1) and MBC 150 mu g mL(-1)). To study the effect of AMPs in general, and EC-hepcidin1 in particular, a primary cell culture (SC) from the fin tissue of the Caspian Trout (Salmo trutta caspius) was established. The neutral Red method on SC cells revealed that EC-hepcidinl has no or very low cytotoxic properties. Treatment of cells with either EC-hepcidinl (150 mu g mL(-1)) or fish pathogen Streptococcus iniae (MOI = 10) and a mixture of both resulted in the up-regulation of gene expression of MHC-UBA, IL-6, and TNF alpha indicating the modulatory function on inflammatory processes. These findings indicate that EC-hepcidinl might act as a candidate for modulation of the innate immune system in S. iniae-based infection.