title: Prostaglandin E(2) modulation of gene expression in an Atlantic salmon (Salmo salar) macrophage-like cell line (SHK-1).
abstract: Following lipopolysaccharide (LPS)-stimulation of Atlantic salmon (Salmo salar) macrophage-like SHK-1 cells, prostaglandin E(2) (PGE(2)) exhibited dose-dependent inhibition of the antigen presenting molecules major histocompatability class I and II and the pro-inflammatory cytokine interleukin-1 beta gene expression. Prostaglandin E(2) was found to be stimulatory towards cyclooxygenase-2 (COX-2) expression at higher concentrations (1 x 10(-6) and 1 x 10(-8)M) and inhibitory at lower concentrations (1 x 10(-10) and 1 x 10(-12)M) after 4h exposure. After 24h exposure, however, LPS-induced COX-2 expression decreased and was completely inhibited by all PGE(2) concentrations (1 x 10(-6)-1 x 10(-10)M). Incubation of SHK-1 cells with LPS alone had no effect on tumour necrosis factor alpha (TNFalpha)-like gene or transforming growth factor beta-like gene expression after 4h, however, LPS and PGE(2) showed a synergistic effect on TNFalpha-like gene expression after 24h. This study provides evidence for the existence of a PGE(2)-mediated negative feedback mechanism in the control of PGs through down-regulation of COX-2, as well as for inflammatory responses by the down-regulation of both COX-2 and IL-1 beta. The differential regulation of immune-related genes under these conditions further demonstrates the usefulness of the SHK-1 cell line for studying aspects of salmonid immunology.
authors.affiliation: Department of Biology, Dalhousie University, 1411 Oxford Street, Halifax, NS, Canada B3H 2Z1. mark.fast@nrc-cnrc.gc.ca
authors.forename: M D
authors.initials: MD
authors.lastname: Fast
authors.forename: N W
authors.initials: NW
authors.lastname: Ross
authors.forename: S C
authors.initials: SC
authors.lastname: Johnson
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects; D001483:Base Sequence; D002460:Cell Line; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000494:pharmacology*; D005246:Feedback; D015870:Gene Expression / Q000187:drug effects; D005805:Genes, MHC Class I / Q000187:drug effects; D005802:Genes, MHC Class II / Q000187:drug effects; D007375:Interleukin-1 / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics; D020317:Salmo salar / Q000235:genetics* / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone