title: ATP-Binding Pocket-Targeted Suppression of Src and Syk by Luteolin Contributes to Its Anti-Inflammatory Action.
abstract: Luteolin is a flavonoid identified as a major anti-inflammatory component of Artemisia asiatica. Numerous reports have demonstrated the ability of luteolin to suppress inflammation in a variety of inflammatory conditions. However, its exact anti-inflammatory mechanism has not been fully elucidated. In the present study, the anti-inflammatory mode of action in activated macrophages of luteolin from Artemisia asiatica was examined by employing immunoblotting analysis, a luciferase reporter gene assay, enzyme assays, and an overexpression strategy. Luteolin dose-dependently inhibited the secretion of nitric oxide (NO) and prostaglandin E2 (PGE2) and diminished the levels of mRNA transcripts of inducible NO synthase (iNOS), tumor necrosis factor- (TNF-) α, and cyclooxygenase-2 (COX-2) in lipopolysaccharide- (LPS-) and pam3CSK-treated macrophage-like RAW264.7 cells without displaying cytotoxicity. Luteolin displayed potent NO-inhibitory activity and also suppressed the nuclear translocation of NF-κB (p65 and p50) via blockade of Src and Syk, but not other mitogen-activated kinases. Overexpression of wild type Src and point mutants thereof, and molecular modelling studies, suggest that the ATP-binding pocket may be the luteolin-binding site in Src. These results strongly suggest that luteolin may exert its anti-inflammatory action by suppressing the NF-κB signaling cascade via blockade of ATP binding in Src and Syk.
authors.affiliation: Department of Aerospace, Information Engineering, Bio-Inspired Aerospace Information Laboratory, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: Jeong-Oog
authors.initials: JO
authors.lastname: Lee
authors.affiliation: Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Deok
authors.initials: D
authors.lastname: Jeong
authors.affiliation: School of Systems Biological Science, Soongsil University, Seoul 156-743, Republic of Korea.
authors.forename: Mi-Yeon
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Jae Youl
authors.initials: JY
authors.lastname: Cho
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D047311:Luteolin / Q000494:pharmacology*; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D000072377:Syk Kinase; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D000893:Anti-Inflammatory Agents; D047908:Intracellular Signaling Peptides and Proteins; D009569:Nitric Oxide; D051546:Cyclooxygenase 2; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D019061:src-Family Kinases; D047311:Luteolin