Masahito Hashimoto

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NOD2, a protein associated with susceptibility to Crohn's disease, confers responsiveness to bacterial preparations of lipopolysaccharide and peptidoglycan, but the precise moiety recognized remains elusive. Biochemical and functional analyses identified muramyl dipeptide (MurNAc-L-Ala-D-isoGln) derived from peptidoglycan as the essential structure in(More)
Nucleotide-binding oligomerization domain protein 1 (NOD1) belongs to a family that includes multiple members with NOD and leucine-rich repeats in vertebrates and plants. NOD1 has been suggested to have a role in innate immune responses, but the mechanism involved remains unknown. Here we report that NOD1 mediates the recognition of peptidoglycan derived(More)
Host innate immune responses to microbial components, known as pathogen-associated molecular patterns (PAMPs), are regulated and modified by cellular receptors and serum proteins, including Toll-like receptors (TLRs), CD14, and LPS-binding protein (LBP). We demonstrated that a treponemal membrane lipid inhibited PAMPs-induced immune responses. The chemical(More)
Treponema denticola has been reported to coaggregate with Porphyromonas gingivalis and localize closely together in matured subgingival plaque. In this study of the interaction of T. denticola with P. gingivalis, the P. gingivalis fimbria-binding protein of T. denticola was identified by two-dimensional electrophoresis followed by a ligand overlay assay(More)
Spirochetes are well-known as causative agents of various chronic infectious diseases. Glycolipids of small-sized Treponema spirochetes have been shown to exhibit immunostimulating activities. In this study, we found that a glycoconjugate preparation obtained from Treponema medium (Tm-Gp), an intermediate-sized oral Treponema seen in subgingival plaque from(More)
Nod1 and Nod2 are intracellular proteins that are involved in recognition of bacterial molecules and their genetic variations have been linked to several inflammatory diseases that are strongly affected by environmental factors. However, the distribution of Nod1- and Nod2-stimulatory molecules in different bacterial species and environments is unknown. Here(More)
Lipoteichoic acid (LTA) derived from Staphylococcus aureus is reported to be a ligand of TLR2. However, we previously demonstrated that LTA fraction prepared from bacterial cells contains lipoproteins, which activate cells via TLR2. In this study, we investigated the immunobiological activity of LTA fraction obtained from S. aureus wild-type strain,(More)
Glycoconjugates are distributed on the cell surfaces of some small-sized treponemes and have been reported to be completely different from lipopolysaccharides. We separated a glycoconjugate fraction from Treponema medium ATCC 700293, a medium-sized oral spirochete, to assess its immunobiological activities and elucidate the chemical structure of its(More)
Bacterial fimbriae are associated with a specific adherence factor, adhesin, in their microbial etiology. Porphyromonas gingivalis, as an anaerobic Gram-negative periodontopathogenic organism, is known to possess fimbriae on its cell surfaces. In this study, we demonstrated that P. gingivalis fimbriae and an active synthetic peptide composed of residues 69(More)
Lipoteichoic acid (LTA) is a cell surface glycoconjugate of gram-positive bacteria and is reported to activate the innate immune system. We previously reported that purified LTA obtained from Enterococcus hirae has no immunostimulating activity, but a subfraction (Eh-AF) in an LTA fraction possesses activity. In this study, we established a mouse monoclonal(More)