title: Mast cells limit extracellular levels of IL-13 via a serglycin proteoglycan-serine protease axis.
abstract: Mast cell (MC) granules contain large amounts of proteases of the chymase, tryptase and carboxypeptidase A (MC-CPA) type that are stored in complex with serglycin,a proteoglycan with heparin side chains. Hence, serglycinprotease complexes are released upon MC degranulation and may influence local inflammation. Here we explored the possibility that a serglycin-protease axis may regulate levels of IL-13, a cytokine involved in allergic asthma. Indeed, we found that wild-type MCs efficiently degraded exogenous or endogenously produced IL-13 upon degranulation,whereas serglycin −/− MCs completely lacked this ability.Moreover, MC-mediated IL-13 degradation was blocked both by a serine protease inhibitor and by a heparin antagonist,which suggests that IL-13 degradation is catalyzed by serglycin-dependent serine proteases and that optimal IL-13 degradation is dependent on both the serglycin and the protease component of the serglycin-protease complex.Moreover, IL-13 degradation was abrogated in MC-CPA −/−MC cultures, but was normal in cultures of MCs with an inactivating mutation of MC-CPA, which suggests that the IL-13-degrading serine proteases rely on MC-CPA protein.Together, our data implicate a serglycin-serine protease axis in the regulation of extracellular levels of IL-13. Reduction of IL-13 levels through this mechanism possibly can provide a protective function in the context of allergic inflammation.
authors.affiliation: Department of Anatomy, Physiology, and Biochemistry, Swedish University of Agricultural Sciences, The Biomedical Centre, Box 575, SE-75123 Uppsala, Sweden.
authors.forename: Ida
authors.initials: I
authors.lastname: Waern
authors.forename: Iulia
authors.initials: I
authors.lastname: Karlsson
authors.forename: Michael
authors.initials: M
authors.lastname: Thorpe
authors.forename: Susan M
authors.initials: SM
authors.lastname: Schlenner
authors.forename: Thorsten B
authors.initials: TB
authors.lastname: Feyerabend
authors.forename: Hans-Reimer
authors.initials: HR
authors.lastname: Rodewald
authors.forename: Magnus
authors.initials: M
authors.lastname: Åbrink
authors.forename: Lars
authors.initials: L
authors.lastname: Hellman
authors.forename: Gunnar
authors.initials: G
authors.lastname: Pejler
authors.forename: Sara
authors.initials: S
authors.lastname: Wernersson
mesh_terms: D000818:Animals; D043422:Carboxypeptidases A / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015550:Cell Degranulation; D002478:Cells, Cultured; D017353:Gene Deletion; D006493:Heparin / Q000276:immunology / Q000378:metabolism; D006494:Heparin Antagonists / Q000494:pharmacology; D006967:Hypersensitivity / Q000276:immunology / Q000378:metabolism; D018793:Interleukin-13 / Q000276:immunology / Q000378:metabolism*; D008407:Mast Cells / Q000502:physiology*; D051379:Mice; D010537:Peritoneum / Q000166:cytology; D011509:Proteoglycans / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D059748:Proteolysis; D057057:Serine Proteases / Q000276:immunology / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D006494:Heparin Antagonists; D018793:Interleukin-13; D011509:Proteoglycans; D015842:Serine Proteinase Inhibitors; D033921:Vesicular Transport Proteins; C075430:serglycin; D006493:Heparin; D057057:Serine Proteases; D043422:Carboxypeptidases A