TY - JOUR
T1 - Dectin-2 recognises mannosylated O-antigens of human opportunistic pathogens and augments lipopolysaccharide activation of myeloid cells
AU - Wittmann, Alexandra
AU - Lamprinaki, Dimitra
AU - Bowles, Kristian M.
AU - Katzenellenbogen, Ewa
AU - Knirel, Yuriy A.
AU - Whitfield, Chris
AU - Nishimura, Takashi
AU - Matsumoto, Naoki
AU - Yamamoto, Kazuo
AU - Iwakura, Yoichiro
AU - Saijo, Shinobu
AU - Kawasaki, Norihito
N1 - © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
Author's Choice—Final version free via Creative Commons CC-BY license.
PY - 2016/8/19
Y1 - 2016/8/19
N2 - Lipopolysaccharide (LPS) consists of a relatively conserved region of lipid A and core-oligosaccharide, and a highly variable region of O-antigen polysaccharide. While lipid A is known to bind to the toll-like receptor 4 (TLR4)-myeloid differentiation factor 2 (MD2) complex, the role of the O-antigen remains unclear. Here we report a novel molecular interaction between dendritic cell-associated C-type lectin-2 (Dectin-2) and the mannosylated O-antigen found in a human opportunistic pathogen Hafnia alvei PCM 1223, which has a repeating unit of [-Man-α1,3-Man-α1,2-Man-α1,2-Man-α1,2-Man-α1,3-]. H. alvei LPS induced higher levels of TNFα and IL-10 from mouse bone marrow-derived dendritic cells (BM-DCs), when compared to Salmonella enterica O66 LPS which has a repeat of [-Gal-α1,6-Gal-α1,4-[Glc-β1,3]GalNAc-α1,3-GalNAc-β1,3-]. In a cell-based reporter assay, Dectin-2 was shown to recognise H. alvei LPS. This binding was inhibited by mannosidase treatment of H. alvei LPS and by mutations in the carbohydrate-binding domain of Dectin-2, demonstrating that H. alvei LPS is a novel glycan ligand of Dectin-2. The enhanced cytokine production by H. alvei LPS was Dectin-2 dependent, as Dectin-2 knockout BM-DCs failed to do so. This receptor crosstalk between Dectin-2 and TLR4 involved events including spleen tyrosine kinase (Syk) activation and receptor juxtaposition. Furthermore, another mannosylated LPS from Escherichia coli O9a, also bound to Dectin-2 and augmented TLR4 activation of BM-DCs. Taken together, these data indicate that mannosylated O-antigens from several gram-negative bacteria augment TLR4 responses through interaction with Dectin-2.
AB - Lipopolysaccharide (LPS) consists of a relatively conserved region of lipid A and core-oligosaccharide, and a highly variable region of O-antigen polysaccharide. While lipid A is known to bind to the toll-like receptor 4 (TLR4)-myeloid differentiation factor 2 (MD2) complex, the role of the O-antigen remains unclear. Here we report a novel molecular interaction between dendritic cell-associated C-type lectin-2 (Dectin-2) and the mannosylated O-antigen found in a human opportunistic pathogen Hafnia alvei PCM 1223, which has a repeating unit of [-Man-α1,3-Man-α1,2-Man-α1,2-Man-α1,2-Man-α1,3-]. H. alvei LPS induced higher levels of TNFα and IL-10 from mouse bone marrow-derived dendritic cells (BM-DCs), when compared to Salmonella enterica O66 LPS which has a repeat of [-Gal-α1,6-Gal-α1,4-[Glc-β1,3]GalNAc-α1,3-GalNAc-β1,3-]. In a cell-based reporter assay, Dectin-2 was shown to recognise H. alvei LPS. This binding was inhibited by mannosidase treatment of H. alvei LPS and by mutations in the carbohydrate-binding domain of Dectin-2, demonstrating that H. alvei LPS is a novel glycan ligand of Dectin-2. The enhanced cytokine production by H. alvei LPS was Dectin-2 dependent, as Dectin-2 knockout BM-DCs failed to do so. This receptor crosstalk between Dectin-2 and TLR4 involved events including spleen tyrosine kinase (Syk) activation and receptor juxtaposition. Furthermore, another mannosylated LPS from Escherichia coli O9a, also bound to Dectin-2 and augmented TLR4 activation of BM-DCs. Taken together, these data indicate that mannosylated O-antigens from several gram-negative bacteria augment TLR4 responses through interaction with Dectin-2.
U2 - 10.1074/jbc.M116.741256
DO - 10.1074/jbc.M116.741256
M3 - Article
VL - 291
SP - 17629
EP - 17638
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 34
ER -