title: Differential regulation of cathelicidin in salmon and cod.
abstract: Antimicrobial peptides (AMPs) are an important component of innate immunity in vertebrates. The cathelicidin family of AMPs is well characterized in mammals and has also been reported in several fish species. In this study we investigated the regulation of cathelicidin expression in a gadoid and a salmonid cell-line in order to dissect the signalling pathways involved. For this, fish cells were treated with microbial lysates, purified microbial components and commercial signalling inhibitors and expression of cathelicidin was assessed with quantitative real-time PCR (qPCR). We found that cathelicidin expression was induced in both cell lines in response to microbial stimuli, but the response patterns differed in these evolutionary distant fish species. Our data suggest that in salmonids, pattern recognition receptors such as TLR5 may be involved in the stimulation of cathelicidin expression and that the signalling cascade can include PI3-kinase and cellular trafficking compartments. A detailed knowledge of the regulating factors involved in AMP-related defence responses, including cathelicidin, could help in developing strategies to enhance the immune defence of fish.
authors.affiliation: Institute of Biology, University of Iceland, Sturlagata 7, 101 Reykjavik, Iceland.
authors.forename: Daniela C
authors.initials: DC
authors.lastname: Broekman
authors.forename: Guðmundur H
authors.initials: GH
authors.lastname: Guðmundsson
authors.forename: Valerie H
authors.initials: VH
authors.lastname: Maier
mesh_terms: D000818:Animals; D002176:Candida albicans / Q000502:physiology; D054804:Cathelicidins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D048389:Gadus morhua / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D005786:Gene Expression Regulation; D006090:Gram-Negative Bacteria / Q000502:physiology; D007113:Immunity, Innate; D007778:Lactobacillus / Q000502:physiology; D060888:Real-Time Polymerase Chain Reaction; D012474:Salmon / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D015398:Signal Transduction; D013045:Species Specificity
chemical_list: D054804:Cathelicidins; D029941:Fish Proteins
keywords: AMP; Cathelicidin; Cell culture; Cell signalling; ECP; Gene expression; Innate immunity; PAMPs; PI3K; TLR; antimicrobial peptide; extracellular product; h; hours; p.s.; pathogen associated molecular patterns; phosphoinositid-3-kinase; post stimulation; toll-like receptor