title: Structure-activity relationship of alginate oligosaccharides in the induction of cytokine production from RAW264.7 cells.
abstract: Guluronate and mannuronate oligomers with various degree of polymerization were prepared from polyguluronate (PG) and polymannuronate (PM) with an alginate lyase from a Pseudoalteromonas sp., and their activities to induce cytokine secretion from mouse macrophage cell line RAW264.7 cells were examined. Enzymatically depolymerized unsaturated alginate oligomers induced tumor necrosis factor (TNF)-alpha secretion from RAW264.7 cells in a structure-depending manner, while the activities of saturated alginate oligomers prepared by acid hydrolysis were fairly low or only trace levels. These results suggest that unsaturated end-structure of alginate oligomers was important for the TNF-alpha-inducing activity. Among the unsaturated guluronate (G3-G9) and mannuronate (M3-M9) oligomers, G8 and M7 showed the most potent activity, respectively. Bio-Plex assay revealed that interleukin (IL)-1alpha, IL-1beta, and IL-6 secretion from RAW264.7 cells were also induced by unsaturated alginate oligomers with similar structure-activity relationship profiles as seen in TNF-alpha, and the most potent activities were observed with G8 and M7. These results suggest that G8 and M7 may have the most suitable molecular size or entire structural conformation as stimulant for cytokine secretion. Since antibodies to Toll-like receptor (TLR)2 and TLR4 effectively inhibited the G8- and M7-induced production of TNF-alpha, these alginate oligomers may stimulate innate immunity through the pattern recognition receptors on macrophages similar to microbial products.
authors.affiliation: Division of Biochemistry, Faculty of Fisheries, Nagasaki University, Nagasaki 852 8521, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Maki
authors.initials: M
authors.lastname: Kurachi
authors.forename: Takuji
authors.initials: T
authors.lastname: Nakashima
authors.forename: Daekyung
authors.initials: D
authors.lastname: Kim
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Oda
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Muramatsu
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007378:Interleukins / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009844:Oligosaccharides / Q000737:chemistry* / Q000494:pharmacology*; D011133:Polysaccharide-Lyases / Q000737:chemistry; D031161:Pseudoalteromonas / Q000201:enzymology; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D013329:Structure-Activity Relationship; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000464:Alginates; D019138:Antibodies, Blocking; D016207:Cytokines; D006603:Hexuronic Acids; D007378:Interleukins; D009844:Oligosaccharides; D011971:Receptors, Immunologic; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C007896:guluronic acid; D020723:Glucuronic Acid; C008324:mannuronic acid; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase