title: Demethylation of SFRP2 by histone demethylase KDM2A regulated osteo-/dentinogenic differentiation of stem cells of the apical papilla.
abstract: OBJECTIVE
  Dental mesenchymal stem cells (MSCs) are easily obtained; however, mechanisms underlying directed differentiation of these cells remains unclear. Wnt/β-catenin signalling is essential for mesenchymal cell commitment and differentiation, and Wnt inhibition is linked to stem cell maintenance and function. Secreted frizzled-related protein 2 (SFRP2) competes with the Frizzled receptor for direct binding to Wnt and blocks activation of Wnt signalling. Here, we used stem cells derived from apical papillae (SCAPs) to study the functions of SFRP2.
  
  
  METHODS
  SCAPs were isolated from apical papillae of immature third molars. The cells were analysed using alkaline phosphatase activity assays, Alizarin red staining and quantitative calcium measurements. In addition, we evaluated expression profile of genes associated with osteogenesis and dentinogenesis (osteo-/dentinogenesis), and conducted in vivo transplantation experiments to determine osteo-/dentinogenic differentiation potential of SCAPs. ChIP assays were used to detect histone methylation at the SFRP2 promoter.
  
  
  RESULTS
  We found that SFRP2 enhanced osteo-/dentinogenic differentiation via Osterix, a key transcription factor in SCAPs. Furthermore, silencing SFRP2 induced SCAP cell death in osteogenic-inducing medium, indicating that SFRP2 is a key factor in maintaining SCAP survival following osteo-/dentinogenic commitment. Moreover, we found that silencing KDM2A, a histone demethylase and BCL6 co-repressor, de-repressed SFRP2 transcription by increasing histone H3K4 and H3K36 methylation at the SFRP2 promoter.
  
  
  CONCLUSIONS
  Our results have identified a new function of SFRP2 and shed new light on the molecular mechanism underlying directed differentiation of stem cells of dental origin.
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.|Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.|Department of Stomatology, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
authors.forename: Guoxia
authors.initials: G
authors.lastname: Yu
authors.affiliation: Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.|Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, Beijing, 100069, China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Wang
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.|Department of Implant Dentistry, Capital Medical University School of Stomatology, Beijing, 100050, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Lin
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Diao
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.|Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Dong
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.affiliation: Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.|Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, Beijing, 100069, China.
authors.forename: Songlin
authors.initials: S
authors.lastname: Wang
authors.affiliation: Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, 100050, China.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Fan
mesh_terms: D002454:Cell Differentiation; D002478:Cells, Cultured; D003771:Dental Papilla / Q000166:cytology* / Q000378:metabolism; D003810:Dentinogenesis; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D008745:Methylation; D010012:Osteogenesis; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D015854:Up-Regulation; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D044783:F-Box Proteins; D006657:Histones; D056484:Jumonji Domain-Containing Histone Demethylases; D008565:Membrane Proteins; D034741:RNA, Small Interfering; C109618:SFRP2 protein, human; D000094742:Secreted Frizzled-Related Proteins; C534524:KDM2A protein, human