title: Molecular mechanisms of lipopolysaccharide-induced cyclooxygenase-2 expression in human neutrophils: involvement of the mitogen-activated protein kinase pathway and regulation by anti-inflammatory cytokines.
abstract: Neutrophils are an important cellular source of proinflammatory mediators, whose regulation may be of potential benefit for the treatment of a number of inflammatory diseases. However, the mechanisms of lipopolysaccharide (LPS)-induced neutrophil activation and its regulation by anti-inflammatory cytokines have not yet been fully elucidated. Recent studies have revealed that mitogen-activated protein kinases (MAPK) play a crucial role in the generation of proinflammatory mediators in some cell types. Therefore, we conducted this study to determine whether MAPK activation could be involved in prostaglandin E(2) (PGE(2)) production and cyclooxygenase (COX)-2 expression in LPS-stimulated human neutrophils. PD98059 (MEK1 inhibitor) and SB203580 (p38(MAPK) inhibitor) reduced PGE(2) production as well as COX-2 expression in LPS-stimulated neutrophils. In addition, both extracellular signal-regulated protein kinase (ERK) and p38(MAPK) were phosphorylated and activated in time- and dose-dependent manners. Since we previously showed that IL-10 and IL-4 similarly inhibited COX-2 expression in LPS-stimulated neutrophils, we next tested the effects of IL-10 and IL-4 on the phosphorylation and activation of both kinases. IL-10 inhibited the phosphorylation and activation of p38(MAPK), but not ERK. In addition, IL-4 caused a marginal inhibition in the activation of p38(MAPK). Taken together, these results suggest that both ERK and p38(MAPK) pathways are involved in LPS-induced COX-2 expression and PGE(2) production in neutrophils, and IL-10 and IL-4 inhibit neutrophil prostanoid synthesis by down-regulating the activation of p38(MAPK).
authors.affiliation: Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Nagano
authors.forename: Takeshi
authors.initials: T
authors.lastname: Otsuka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Niiro
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Yamaoka
authors.forename: Yojirou
authors.initials: Y
authors.lastname: Arinobu
authors.forename: Eiichi
authors.initials: E
authors.lastname: Ogami
authors.forename: Mitsuteru
authors.initials: M
authors.lastname: Akahoshi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Miyake
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakashima
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Niho
authors.forename: Mine
authors.initials: M
authors.lastname: Harada
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D016753:Interleukin-10 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis*; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D007527:Isoenzymes; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D011725:Pyridines; D016753:Interleukin-10; D015847:Interleukin-4; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; D015232:Dinoprostone; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one