title: Notch inhibits chondrogenic differentiation of mesenchymal progenitor cells by targeting Twist1.
abstract: While Notch signaling plays a critical role in the regulation of cartilage formation, its downstream targets are unknown. To address this we performed gain and losses of function experiments and demonstrate that Notch inhibition of chondrogenesis acts via up-regulation of the transcription factor Twist1. Upon Notch activation, murine limb bud mesenchymal progenitor cells in micromass culture displayed an inhibition of chondrogenesis. Twist1 was found to be exclusively expressed in mesenchymal progenitor cells at the onset stage of chondrogenesis during Notch activation. Inhibition of Notch signaling in these cells significantly reduced protein expression of Twist1. Furthermore, the inhibition effect of NICD1 on MPC chondrogenesis was markedly reduced by knocking down of Twist1. Constitutively active Notch signaling significantly enhanced Twist1 promoter activity; whereas mutation studies indicated that a putative NICD/RBPjK binding element in the promoter region is required for the Notch-responsiveness of the Twist1 promoter. Finally, chromatin immunoprecipitation assays further confirmed that the Notch intracellular domain influences Twist1 by directly binding to the Twist1 promoter. These data provide a novel insight into understanding the molecular mechanisms behind Notch inhibition of the onset of chondrogenesis.
authors.affiliation: Department of Orthopaedics, Shengjing Hospital, China Medical University, 36 Sanhao Road, Shenyang 110004, China. Electronic address: tianyecmusjh@sina.com.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Anesthesiology, Shengjing Hospital, China Medical University, 36 Sanhao Road, Shenyang 110004, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Orthopaedics, Shengjing Hospital, China Medical University, 36 Sanhao Road, Shenyang 110004, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester School of Medicine, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Chang
authors.affiliation: Institute of Spine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Orthopaedic Surgery, Anhui Provincial Hospital, Hefei 230001, China.
authors.forename: Xifu
authors.initials: X
authors.lastname: Shang
authors.affiliation: Ministry of Education Key Laboratory for Regenerative Medicine, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wan
authors.affiliation: Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
authors.forename: John V
authors.initials: JV
authors.lastname: Marymont
authors.affiliation: Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Dong
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D020219:Chondrogenesis; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000235:genetics / Q000378:metabolism; D018878:Limb Buds / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D009687:Nuclear Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D061251:Primary Cell Culture; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051881:Receptor, Notch1 / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D051879:Twist-Related Protein 1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; C497762:Notch1 protein, mouse; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C497571:Rbpj protein, mouse; D051881:Receptor, Notch1; D051879:Twist-Related Protein 1; C067250:Twist1 protein, mouse
keywords: Chondrogenesis; Mesenchymal progenitor cell; Notch signaling; Twist1