title: Production and mechanism of secretion of interleukin-1beta from the marine fish gilthead seabream.
abstract: Mammalian interleukin-1beta (IL-1beta) is a secretory cytokine lacking a signal peptide, which does not follow the classical endoplasmic reticulum to Golgi pathway of secretion. Its post-translational processing by IL-1beta-converting enzyme (ICE) and subsequent release from activated macrophages requires ATP acting on P2X7 receptors. Little information is available on the production and release of fish IL-1beta, but the IL-1beta gene sequences reported to date lack a conserved ICE recognition site. We show for the first time that lipopolysaccharide (LPS)/macrophage-activating factor/bacterial DNA (VaDNA)-primed immune cells of the marine fish gilthead seabream (Sparus aurata) accumulate intracellular IL-1beta as a approximately 30 kDa polypeptide (proIL-1beta). The combination of LPS and VaDNA was found to be synergistic, suggesting that each ligand is recognized by a different pattern recognition receptor. More importantly, addition of extracellular ATP does not promote IL-1beta secretion by immune cells and fails to induce phosphatidylserine flip. In contrast, gilthead seabream SAF-1 fibroblasts shed microvesicles containing a 22 kDa IL-1beta form within 30 min of activation with ATP. Notably, the post-translational processing of IL-1beta by SAF-1 cells is abrogated by a specific ICE inhibitor.
authors.affiliation: Department of Cell Biology, Faculty of Biology, University of Murcia, Campus Universitario de Espinardo, 30100, Murcia, Spain
authors.forename: Pablo
authors.initials: P
authors.lastname: Pelegrín
authors.forename: Elena
authors.initials: E
authors.lastname: Chaves-Pozo
authors.forename: Victoriano
authors.initials: V
authors.lastname: Mulero
authors.forename: José
authors.initials: J
authors.lastname: Meseguer
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D017304:Annexin A5 / Q000032:analysis / Q000494:pharmacology; D000906:Antibodies / Q000276:immunology; D015153:Blotting, Western; D061945:Caspase Inhibitors; D002460:Cell Line; D004269:DNA, Bacterial / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D005822:Genetic Vectors / Q000235:genetics; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D007962:Leukocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D016215:Macrophage-Activating Factors / Q000494:pharmacology; D008264:Macrophages / Q000737:chemistry / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009842:Oligopeptides / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D021541:Sea Bream / Q000276:immunology / Q000502:physiology*; D014170:Transformation, Genetic; D014733:Vibrio / Q000235:genetics
chemical_list: D017304:Annexin A5; D000906:Antibodies; D061945:Caspase Inhibitors; D004269:DNA, Bacterial; D018076:DNA, Complementary; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016215:Macrophage-Activating Factors; D009842:Oligopeptides; C118632:tyrosyl-valyl-alanyl-aspartal; D000255:Adenosine Triphosphate