title: Toll-like receptor 4-dependent recognition of structurally different forms of chemically synthesized lipid As of Porphyromonas gingivalis.
abstract: Porphyromonas gingivalis is a Gram-negative anaerobic oral black-pigmented bacterium closely associated with chronic periodontitis. Lipopolysaccharide (LPS) derived from P. gingivalis is shown to be unusual because the LPS contains a greater number of lipid A species, such as tri-, tetra-, and/or penta-acylated lipid As. In this study, a lipid A possessing penta-fatty acyl chains derived from P. gingivalis strain 381 (compound PG-381-5FA) was synthesized, and examined for its immunobiological activities, compared with a tri-acylated lipid A (compound PG-381-3FA) synthesized previously. Compound PG-381-5FA, similar to compound PG-381-3FA, demonstrated weaker activity in a Limulus test as compared with Escherichia coli-type synthetic lipid A (compound 506). Compound PG-381-5FA, followed by compound PG-381-3FA, induced KC, interleukin-6, and tumour necrosis factor-alpha production in peritoneal macrophages from LPS-responsive C3H/HeN mice, but not in those from LPS-hyporesponsive C3H/HeJ mice. Furthermore, compound PG-381-5FA, as well as compound PG-381-3FA, activated nuclear factor-kappaB via Toll-like receptor (TLR)4/mD-2, but not TLR2, in a manner similar to compound 506, and worked as an antagonist for compound 506-induced cell activation. In the case of human peripheral blood mononuclear cells, compound PG-381-5FA showed much stronger IL-6-inducing activity than compound PG-381-3FA. The present results demonstrate that the chemical synthesis of a penta-acylated lipid A, mimicking the natural lipid A portion of LPS from P. gingivalis, is attributable to immune cell activation through TLR4, similar to that of compound 506.
authors.affiliation: Department of Oral Microbiology, Asahi University School of Dentistry, Gifu, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Sawada
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: Y
authors.initials: Y
authors.lastname: Asai
authors.forename: Y
authors.initials: Y
authors.lastname: Makimura
authors.forename: A
authors.initials: A
authors.lastname: Sugiyama
mesh_terms: D000328:Adult; D000818:Animals; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008050:Lipid A / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000276:immunology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D016328:NF-kappa B / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000276:immunology*; D013329:Structure-Activity Relationship; D051197:Toll-Like Receptor 4 / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D015850:Interleukin-6; D008050:Lipid A; D008070:Lipopolysaccharides; D016328:NF-kappa B; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha