title: Novel mechanism of U18666A-induced tumour necrosis factor-alpha production in RAW 264.7 macrophage cells.
abstract: U18666A is a cholesterol transport-inhibiting agent that is used widely to mimic Niemann-Pick type C disease. The effect of U18666A on tumour necrosis factor (TNF)-alpha production in mouse macrophage cell line, RAW 264.7 cells and peritoneal macrophages was examined. U18666A induced TNF-alpha mRNA expression 48 h after the treatment, and TNF-alpha production 48 and 72 h after stimulation in RAW 264.7 cells. U18666A accumulated intracellular free cholesterol in the culture of normal medium but not cholesterol-free medium. U18666A also induced reactive oxygen species (ROS) generation in normal medium but much less in cholesterol-free medium. Anti-oxidant N-acetyl-L-cysteine (NAC) abolished U18666A-induced TNF-alpha production. U18666A led to the phosphorylation of p38 mitogen-activated protein kinase 24 and 48 h after the stimulation and the p38 activation was inhibited in presence of cholesterol-free medium or NAC. A p38 inhibitor reduced U18666A-induced TNF-alpha production. Taken together, U18666A was suggested to induce TNF-alpha production in RAW 264.7 cells via free cholesterol accumulation-mediated ROS generation.
authors.affiliation: Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Iftakhar-E-Khuda
authors.forename: N
authors.initials: N
authors.lastname: Koide
authors.forename: F
authors.initials: F
authors.lastname: Hassan
authors.forename: A S M
authors.initials: AS
authors.lastname: Noman
authors.forename: J
authors.initials: J
authors.lastname: Dagvadorj
authors.forename: G
authors.initials: G
authors.lastname: Tumurkhuu
authors.forename: Y
authors.initials: Y
authors.lastname: Naiki
authors.forename: T
authors.initials: T
authors.lastname: Komatsu
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Yokochi
mesh_terms: D000736:Androstenes / Q000494:pharmacology*; D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D004789:Enzyme Activation; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009542:Niemann-Pick Diseases / Q000276:immunology; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000736:Androstenes; D000924:Anticholesteremic Agents; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C006261:3-beta-(2-(diethylamino)ethoxy)androst-5-en-17-one; D002784:Cholesterol; D048051:p38 Mitogen-Activated Protein Kinases