title: Comparative study on modeccin- and phytohemagglutinin (PHA)-induced secretion of cytokines and nitric oxide (NO) in RAW264.7 cells.
abstract: The effects of cytotoxic lectins, modeccin and phytohemagglutinin (PHA) on mouse macrophage cell line RAW264.7 was studied by detecting the induction of inflammatory mediators. Results showed that modeccin induced the release of tumor necrosis factor-α (TNF-α) from RAW264.7 cells with a bell-shape concentration-dependent profile. PHA that showed no significant cytotoxicity on RAW264.7 cells up to 100,000 ng/ml induced much higher level of TNF-α than modeccin. PHA simultaneously induced the secretion of granulocyte colony stimulation factor (G-CSF) from RAW264.7 cells with even much higher level than that of TNF-α, whereas modeccin did not. Furthermore, PHA induced the secretion of nitric oxide (NO) in RAW264.7 cells, while no significant level of NO was detected in the modeccin-treated cells. NH₄Cl (a lysomotoropic agent) and cycloheximide (a ribosome inhibitor) strongly inhibited modeccin-induced TNF-α secretion, but no significant inhibitory effects of these reagents on the PHA-induced TNF-α secretion were observed. Contrary to modeccin-induced TNF-α secretion, even slightly increased TNF-α secretion was observed in PHA-treated cells in the presence of 10 mM NH₄Cl. In addition, the inhibition profiles of modeccin-induced TNF-α secretion by various kinase inhibitors were different from those of PHA. These results suggested that the action mode of modeccin to stimulate RAW264.7 cells leading to the secretion of inflammatory molecules, including TNF-α, is distinct from that of PHA. On the other hand, significantly increased translocation of activator protein-1 (AP-1), a crucial transcription factor involved in expression of inflammatory molecules, into nucleus was observed in RAW264.7 cells treated with PHA and modeccin.
authors.affiliation: Jeju Center, Korea Basic Science Institute, Jeju-Si, Jeju Special Self-Governing Province, South Korea.
authors.forename: Daekyung
authors.initials: D
authors.lastname: Kim
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamasaki
authors.forename: Zedong
authors.initials: Z
authors.lastname: Jiang
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yamanishi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Oda
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism*; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D010835:Phytohemagglutinins / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D054790:Ribosome Inactivating Proteins, Type 2 / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D010835:Phytohemagglutinins; D054790:Ribosome Inactivating Proteins, Type 2; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D016179:Granulocyte Colony-Stimulating Factor; D009569:Nitric Oxide; C016004:modeccin; D003513:Cycloheximide; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse