title: miR-148a is a downstream effector of X-box-binding protein 1 that silences Wnt10b during adipogenesis of 3T3-L1 cells.
abstract: Wnt10b, an endogenous inhibitor of adipogenesis, maintains preadipocytes in an undifferentiated state by suppressing adipogenic transcription factors. We have previously demonstrated that Wnt10b transcription during adipogenesis is negatively regulated by X-box-binding protein 1 (XBP1), an important transcription factor of the unfolded protein response. In this report, we demonstrate that XBP1s can directly induce the transcription of microRNA-148a, which in turn mediates the silencing of Wnt10b mRNA during adipogenic differentiation of 3T3-L1 cells. Stability of Wnt10b mRNA was found to be significantly increased by knockdown of XBP1s. Using computational algorithms, a set of microRNAs was predicted to bind Wnt10b mRNA, of which microRNA-148a was selected as a potential target for XBP1s. Our results revealed that microRNA-148a could bind to the 3'UTR of Wnt10b mRNA. Its ectopic expression significantly suppressed both Wnt10b expression and β-catenin activity. When we altered the expression of XBP1 in 3T3-L1 cells, microRNA-148a levels changed accordingly. A potential XBP1 response element was found in the promoter region of microRNA-148a, and XBP1s directly bound to this response element as shown by point mutation analysis and chromatin immunoprecipitation assay. In addition, a microRNA-148a mimic significantly restored adipogenic potential in XBP1-deficient 3T3-L1 cells. These findings provide the first evidence that XBP1s can regulate Wnt10b by a post-transcriptional mechanism through directly inducing microRNA-148a.
authors.affiliation: Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Yoon Mi
authors.initials: YM
authors.lastname: Cho
authors.affiliation: Department of Medical Informatics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Tae-Min
authors.initials: TM
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Dae
authors.identifier: http://orcid.org/0000-0002-9942-8239
authors.initials: D
authors.lastname: Hun Kim
authors.affiliation: Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Dong
authors.initials: D
authors.lastname: Hee Kim
authors.affiliation: Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Seong-Whan
authors.initials: SW
authors.lastname: Jeong
authors.affiliation: Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Oh-Joo
authors.initials: OJ
authors.lastname: Kwon
mesh_terms: D020413:3' Untranslated Regions; D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics*; D000818:Animals; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D034622:RNA Interference; D020871:RNA Stability; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D051153:Wnt Proteins / Q000235:genetics*; D060449:Wnt Signaling Pathway; D000071717:X-Box Binding Protein 1
chemical_list: D020413:3' Untranslated Regions; D004268:DNA-Binding Proteins; D035683:MicroRNAs; C554644:Mirn148 microRNA, mouse; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; D051153:Wnt Proteins; C102068:Wnt10b protein, mouse; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse