title: Differential responses of mast cell Toll-like receptors 2 and 4 in allergy and innate immunity.
abstract: Toll-like receptor 2 (TLR2) and TLR4 play important roles in the early innate immune response to microbial challenge. To clarify the functional roles of TLRs 2 and 4 in mast cells, we examined bone marrow-derived mast cells (BMMCs) from TLR2 or TLR4 gene-targeted mice. Peptidoglycan (PGN) from Staphylococcus aureus stimulated mast cells in a TLR2-dependent manner to produce TNF-alpha, IL-4, IL-5, IL-6, and IL-13, but not IL-1beta. In contrast, LPS from Escherichia coli stimulated mast cells in a TLR4-dependent manner to produce TNF-alpha, IL-1beta, IL-6, and IL-13, but not IL-4 nor IL-5. Furthermore, TLR2- but not TLR4-dependent mast cell stimulation resulted in mast cell degranulation and Ca2+ mobilization. In a mast cell-dependent model of acute sepsis, TLR4 deficiency of BMMCs in mice resulted in significantly higher mortality because of defective neutrophil recruitment and production of proinflammatory cytokines in the peritoneal cavity. Intradermal injection of PGN led to increased vasodilatation and inflammation through TLR2-dependent activation of mast cells in the skin. Taken together, these results suggest that direct activation of mast cells via TLR2 or TLR4 by respective microligands contributes to innate and allergic immune responses.
authors.affiliation: Department of Dermatology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Volaluck
authors.initials: V
authors.lastname: Supajatura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ushio
authors.forename: Atsuhito
authors.initials: A
authors.lastname: Nakao
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Ko
authors.initials: K
authors.lastname: Okumura
authors.forename: Chisei
authors.initials: C
authors.lastname: Ra
authors.forename: Hideoki
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000276:immunology*; D029721:Drosophila Proteins; D004926:Escherichia coli / Q000276:immunology; D006967:Hypersensitivity / Q000276:immunology*; D007113:Immunity, Innate / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D010457:Peptidoglycan / Q000276:immunology / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000276:immunology*; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D012867:Skin / Q000276:immunology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000276:immunology; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors
chemical_list: D029721:Drosophila Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D010457:Peptidoglycan; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors