title: Bixin regulates mRNA expression involved in adipogenesis and enhances insulin sensitivity in 3T3-L1 adipocytes through PPARgamma activation.
abstract: Insulin resistance is partly due to suppression of insulin-induced glucose uptake into adipocytes. The uptake is dependent on adipocyte differentiation, which is controlled at mRNA transcription level. The peroxisome proliferator-activated receptor (PPAR), a ligand-regulated nuclear receptor, is involved in the differentiation. Many food-derived compounds serve as ligands to activate or inactivate PPAR. In this study, we demonstrated that bixin and norbixin (annatto extracts) activate PPARgamma by luciferase reporter assay using GAL4-PPAR chimera proteins. To examine the effects of bixin on adipocytes, 3T3-L1 adipocytes were treated with bixin or norbixin. The treatment induced mRNA expression of PPARgamma target genes such as adipocyte-specific fatty acid-binding protein (aP2), lipoprotein lipase (LPL), and adiponectin in differentiated 3T3-L1 adipocytes and enhanced insulin-dependent glucose uptake. The observations indicate that bixin acts as an agonist of PPARgamma and enhances insulin sensitivity in 3T3-L1 adipocytes, suggesting that bixin is a valuable food-derived compound as a PPAR ligand to regulate lipid metabolism and to ameliorate metabolic syndrome.
authors.affiliation: Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Goto
authors.forename: Aki
authors.initials: A
authors.lastname: Taimatsu
authors.forename: Kahori
authors.initials: K
authors.lastname: Egawa
authors.forename: Sota
authors.initials: S
authors.lastname: Katoh
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kusudo
authors.forename: Tomoya
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Chie
authors.initials: C
authors.lastname: Ohyane
authors.forename: Joo-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Young-Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Taku
authors.initials: T
authors.lastname: Uemura
authors.forename: Shizuka
authors.initials: S
authors.lastname: Hirai
authors.forename: Teruo
authors.initials: T
authors.lastname: Kawada
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects*; D000818:Animals; D002338:Carotenoids / Q000494:pharmacology*; D017930:Genes, Reporter / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000187:drug effects; D008156:Luciferases / Q000235:genetics; D051379:Mice; D047495:PPAR gamma / Q000819:agonists*; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D007328:Insulin; D047495:PPAR gamma; D012333:RNA, Messenger; D002338:Carotenoids; C004588:bixin; C099823:norbixin; D008156:Luciferases; D005947:Glucose