title: Bromocriptine inhibits adipogenesis and lipogenesis by agonistic action on α2-adrenergic receptor in 3T3-L1 adipocyte cells.
abstract: The primary goals of the present study were to investigate the inhibitory effects of bromocriptine (BC) on adipogenesis and lipogenesis in 3T3-L1 adipocyte cells as well as to elucidate its molecular mechanism of action. Adipogenic and lipogenic capacity of BC-treated cells was evaluated by oil red-O staining, triglyceride content assay, real-time RT-PCR and immunoblotting. To determine the mechanism responsible for the anti-obesity effect of BC, we applied two methods. Firstly, we knocked down dopamine D2 receptor (D2R) up to 50% using siRNA. Secondly, we blocked the activity of α2-adrenergic receptor (α2-AR) by yohimbine treatment and monitored its effects on adipogenic and lipogenic events in 3T3-L1 cells. BC decreased the expression levels of adipogenic activators, including Pparα, Pparγ, and Cebpα, as well as major lipogenic target genes, including Me1, Acc1, 6Pgd, Fasn, and Prkaa1. Moreover, BC markedly reduced intracellular nitric oxide formation in a dose-dependent manner and expression of pro-inflammatory genes, Tnfα and Il6, which reflects attenuated pro-inflammatory responses. Further, upon treatment with BC, D2R-deficient cells displayed a significant decrease in lipogenic activity compared to control cells, whereas yohimbine-treated cells exhibited no reduction in lipogenic activity. BC can effectively attenuate adipogenesis and lipogenesis in 3T3-L1 cells by downregulating the expression of lipogenic genes and proteins. Our current experimental data collectively establish that the anti-obesity effects of BC are not D2R-dependent but result from the action of α2-AR in 3T3-L1 adipocytes.
authors.affiliation: Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk 712-714, Republic of Korea.
authors.forename: Rajib
authors.initials: R
authors.lastname: Mukherjee
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Yun
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects* / Q000235:genetics; D058669:Adrenergic alpha-2 Receptor Antagonists / Q000494:pharmacology* / Q000633:toxicity; D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology* / Q000633:toxicity; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D050356:Lipid Metabolism; D050155:Lipogenesis / Q000187:drug effects* / Q000235:genetics; D051379:Mice; D034622:RNA Interference; D018341:Receptors, Adrenergic, alpha-2 / Q000235:genetics / Q000378:metabolism
chemical_list: D058669:Adrenergic alpha-2 Receptor Antagonists; D018341:Receptors, Adrenergic, alpha-2; D001971:Bromocriptine