title: NOD2 stimulation by Staphylococcus aureus-derived peptidoglycan is boosted by Toll-like receptor 2 costimulation with lipoproteins in dendritic cells.
abstract: Mutations in the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) play an important role in the pathogenesis of Crohn's disease. NOD2 is an intracellular pattern recognition receptor (PRR) that senses bacterial peptidoglycan (PGN) structures, e.g., muramyl dipeptide (MDP). Here we focused on the effect of more-cross-linked, polymeric PGN fragments (PGNpol) in the activation of the innate immune system. In this study, the effect of combined NOD2 and Toll-like receptor 2 (TLR2) stimulation was examined compared to single stimulation of the NOD2 receptor alone. PGNpol species derived from a lipoprotein-containing Staphylococcus aureus strain (SA113) and a lipoprotein-deficient strain (SA113 Δlgt) were isolated. While PGNpol constitutes a combined NOD2 and TLR2 ligand, lipoprotein-deficient PGNpolΔlgt leads to activation of the immune system only via the NOD2 receptor. Murine bone marrow-derived dendritic cells (BMDCs), J774 cells, and Mono Mac 6 (MM6) cells were stimulated with these ligands. Cytokines (interleukin-6 [IL-6], IL-12p40, and tumor necrosis factor alpha [TNF-α]) as well as DC activation and maturation parameters were measured. Stimulation with PGNpolΔlgt did not lead to enhanced cytokine secretion or DC activation and maturation. However, stimulation with PGNpol led to strong cytokine secretion and subsequent DC maturation. These results were confirmed in MM6 and J774 cells. We showed that the NOD2-mediated activation of DCs with PGNpol was dependent on TLR2 costimulation. Therefore, signaling via both receptors leads to a more potent activation of the immune system than that with stimulation via each receptor alone.
authors.affiliation: Division of Gastroenterology, Department of Medicine II, University of Rostock, Rostock, Germany holger.schaeffler@med.uni-rostock.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Schäffler
authors.affiliation: Microbial Genetics, University of Tübingen, Tübingen, Germany.
authors.forename: Dogan Doruk
authors.initials: DD
authors.lastname: Demircioglu
authors.affiliation: Microbial Genetics, University of Tübingen, Tübingen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kühner
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany Deutsches Zentrum für Infektionsforschung (DZIF), Partner Side Tübingen, Tübingen, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Menz
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany Deutsches Zentrum für Infektionsforschung (DZIF), Partner Side Tübingen, Tübingen, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Bender
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany Deutsches Zentrum für Infektionsforschung (DZIF), Partner Side Tübingen, Tübingen, Germany.
authors.forename: Ingo B
authors.initials: IB
authors.lastname: Autenrieth
authors.affiliation: Division of Gastroenterology, Department of Medicine II, University of Rostock, Rostock, Germany.
authors.forename: Peggy
authors.initials: P
authors.lastname: Bodammer
authors.affiliation: Division of Gastroenterology, Department of Medicine II, University of Rostock, Rostock, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Lamprecht
authors.affiliation: Microbial Genetics, University of Tübingen, Tübingen, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Götz
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany Deutsches Zentrum für Infektionsforschung (DZIF), Partner Side Tübingen, Tübingen, Germany.
authors.forename: Julia-Stefanie
authors.initials: JS
authors.lastname: Frick
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008074:Lipoproteins / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism*; D010457:Peptidoglycan / Q000737:chemistry / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D008074:Lipoproteins; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D010457:Peptidoglycan; C493486:Tlr2 protein, mouse; D051195:Toll-Like Receptor 2