Kirenol inhibits adipogenesis through activation of the Wnt/β-catenin signaling pathway in 3T3-L1 adipocytes

• DOI: 10.1016/j.bbrc.2014.02.017
• Publication Date: 2014-02-12T13:01:56Z
• Authors: Mi-Bo Kim; Youngwoo Song; Changhee Kim; Jae-Kwan Hwang
• Keywords: 0301 basic medicine; Adipogenesis; Anti-Inflammatory Agents; Down-Regulation; Lipid Metabolism; 3. Good health; PPAR gamma; Mice; 03 medical and health sciences; 3T3-L1 Cells; Adipocytes; CCAAT-Enhancer-Binding Protein-alpha; Animals; RNA Interference; Anti-Obesity Agents; Diterpenes; Sterol Regulatory Element Binding Protein 1; Wnt Signaling Pathway; beta Catenin

Kirenol, a natural diterpenoid compound, has been reported to possess anti-oxidant, anti-inflammatory, anti-allergic, and anti-arthritic activities; however, its anti-adipogenic effect remains to be studied. The present study evaluated the effect of kirenol on anti-adipogenesis through the activation of the Wnt/β-catenin signaling pathway. Kirenol prevented intracellular lipid accumulation by down-regulating key adipogenesis transcription factors [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding proteins α (C/EBPα), and sterol regulatory element binding protein-1c (SREBP-1c)] and lipid biosynthesis-related enzymes [fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC)], as well as adipocytokines (adiponectin and leptin). Kirenol effectively activated the Wnt/β-catenin signaling pathway, in which kirenol up-regulated the expression of low density lipoprotein receptor related protein 6 (LRP6), disheveled 2 (DVL2), β-catenin, and cyclin D1 (CCND1), while it inactivated glycogen synthase kinase 3β (GSK3β) by increasing its phosphorylation. Kirenol down-regulated the expression levels of PPARγ and C/EBPα, which were up-regulated by siRNA knockdown of β-catenin. Overall, kirenol is capable of inhibiting the differentiation and lipogenesis of 3T3-L1 adipocytes through the activation of the Wnt/β-catenin signaling pathway, suggesting its potential as natural anti-obesity agent.