title: Cyanidin 3-glucoside protects 3T3-L1 adipocytes against H2O2- or TNF-alpha-induced insulin resistance by inhibiting c-Jun NH2-terminal kinase activation.
abstract: Anthocyanins are naturally occurring plant pigments and exhibit an array of pharmacological properties. Our previous study showed that black rice pigment extract rich in anthocyanin prevents and ameliorates high-fructose-induced insulin resistance in rats. In present study, cyanidin 3-glucoside (Cy-3-G), a typical anthocyanin most abundant in black rice was used to examine its protective effect on insulin sensitivity in 3T3-L1 adipocytes exposed to H(2)O(2) (generated by adding glucose oxidase to the medium) or tumor necrosis factor alpha (TNF-alpha). Twelve-hour exposure of 3T3-L1 adipocytes to H(2)O(2) or TNF-alpha resulted in the increase of c-Jun NH(2)-terminal kinase (JNK) activation and insulin receptor substrate 1 (IRS1) serine 307 phosphorylation, concomitantly with the decrease in insulin-stimulated IRS1 tyrosine phosphorylation and cellular glucose uptake. Blocking JNK expression using RNA interference efficiently prevented the H(2)O(2)- or TNF-alpha-induced defects in insulin action. Pretreatment of cells with Cy-3-G reduced the intracellular production of reactive oxygen species, the activation of JNK, and attenuated H(2)O(2)- or TNF-alpha-induced insulin resistance in a dose-dependent manner. In parallel, N-acetyl-cysteine, an antioxidant compound, did not exhibit an attenuation of TNF-alpha-induced insulin resistance. Taken together, these results indicated that Cy-3-G exerts a protective role against H(2)O(2)- or TNF-alpha-induced insulin resistance in 3T3-L1 adipocytes by inhibiting the JNK signal pathway.
authors.affiliation: Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), 74 Zhongshan Road 2, Guangzhou, Guangdong Province 510080, PR China.
authors.forename: Honghui
authors.initials: H
authors.lastname: Guo
authors.forename: Wenhua
authors.initials: W
authors.lastname: Ling
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Chi
authors.initials: C
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Hu
authors.forename: Min
authors.initials: M
authors.lastname: Xia
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D000872:Anthocyanins / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D005960:Glucosides / Q000494:pharmacology*; D006861:Hydrogen Peroxide; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D051379:Mice; D048055:Mitogen-Activated Protein Kinase 8 / Q000235:genetics / Q000378:metabolism*; D020011:Protective Agents / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha
chemical_list: D000872:Anthocyanins; D005960:Glucosides; D007328:Insulin; D020011:Protective Agents; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C462279:cyanidin-3-O-beta-glucopyranoside; D006861:Hydrogen Peroxide; D048055:Mitogen-Activated Protein Kinase 8; D005947:Glucose