title: Regulation of Wnt/β-catenin signaling by CCAAT/enhancer binding protein β during adipogenesis.
abstract: Activation of the Wnt/β-catenin signaling pathway inhibits adipogenesis, while disruption of Wnt signaling leads to spontaneous adipogenesis. CCAAT/enhancer binding protein β (C/EBPβ) is rapidly induced in early stages of adipogenesis and is responsible for transcriptional induction of two major adipogenic transcription factors, peroxisome proliferator-activated receptor γ (PPARγ) and C/EBPα. In this study, we examined whether C/EBPβ is involved in the suppression of Wnt/β-catenin signaling during adipogenesis. Knockdown of C/EBPβ expression not only inhibited adipogenesis but also maintained active Wnt/β-catenin signaling, after addition of adipogenic inducers. In contrast, overexpression of C/EBPβ substantially inhibited Wnt signaling. Interestingly, our data showed that C/EBPβ is involved in the expression of Wnt10b, a major Wnt ligand in preadipocytes, even though C/EBPβ is not an essential factor to regulate Wnt10b expression during adipogenesis, and that C/EBPβ inhibits Wnt10b promoter activity by directly binding to specific regions of the promoter. These results suggest a dual function of C/EBPβ: stimulating expression of adipogenic genes and inhibiting Wnt signaling.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sung Soo
authors.initials: SS
authors.lastname: Chung
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Lee
authors.forename: Min
authors.initials: M
authors.lastname: Kim
authors.forename: Byung Yong
authors.initials: BY
authors.lastname: Ahn
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Jung
authors.forename: Hak Mo
authors.initials: HM
authors.lastname: Lee
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Kim
authors.forename: Kyong Soo
authors.initials: KS
authors.lastname: Park
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D050156:Adipogenesis / Q000235:genetics; D015153:Blotting, Western; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D006801:Humans; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D060449:Wnt Signaling Pathway / Q000235:genetics
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D047495:PPAR gamma; D011518:Proto-Oncogene Proteins; C491119:WNT10B protein, human; D051153:Wnt Proteins