title: Quercetin regulates the inhibitory effect of monoclonal non-specific suppressor factor beta on tumor necrosis factor-alpha production in LPS-stimulated macrophages.
abstract: Monoclonal non-specific suppressor factor beta (MNSFbeta) is a member of the ubiquitin-like family that has been implicated in various biological functions. Previous studies have demonstrated that MNSFbeta regulates the ERK1/2-MAPK cascade in the macrophage cell line Raw 264.7. In this study, we found evidence that the flavonol quercetin regulates the effect of MNSFbeta on TNFalpha production in LPS-stimulated Raw264.7 cells. Quercetin inhibited MNSFbeta siRNA-mediated enhancement of both TNFalpha production and ERK1/2 phosphorylation in LPS-stimulated Raw264.7 cells. Quercetin decreased the expression of 33.5-kDa MNSFbeta adduct, which is important to the regulation of ERK1/2 activity, in unstimulated Raw264.7 cells. The various flavonoids tested, including other flavonols, did not affect the formation of this adduct. Collectively, MNSFbeta and quercetin might share a common pathway in regulating the ERK1/2 pathway in macrophages. This is the first report describing the involvement of flavonoids in the action of ubiquitin-like proteins.
authors.affiliation: Department of Cooperative Medical Research, Collaboration Center, Shimane University, Izumo, Japan. nkmr0515@med.shimane-u.ac.jp
authors.forename: Morihiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Satomi
authors.initials: S
authors.lastname: Omura
mesh_terms: D000818:Animals; D000975:Antioxidants; D002460:Cell Line; D005419:Flavonoids / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D011794:Quercetin / Q000494:pharmacology*; D034741:RNA, Small Interfering; D013491:Suppressor Factors, Immunologic / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000096:biosynthesis
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D008070:Lipopolysaccharides; D034741:RNA, Small Interfering; D013491:Suppressor Factors, Immunologic; D014409:Tumor Necrosis Factor-alpha; C072169:monoclonal nonspecific suppressor factor; D011794:Quercetin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3