title: KLF4 promotes the odontoblastic differentiation of human dental pulp cells.
abstract: BACKGROUND
  Krüppel-like factor 4 (KLF4) plays an important role in cytodifferentiation and proliferation. Our previous study showed that KLF4 was specifically expressed in polarizing and elongating odontoblasts. However, the role of KLF4 in odontoblast differentiation was still unknown. The purpose of this study was to investigate the role of KLF4 in odontoblastic differentiation of human dental pulp cells (hDPCs).
  
  
  METHODS
  hDPCs were treated with odontoblastic induction medium. Odontoblastic differentiation was determined by the detection of alkaline phosphatase (ALPase) activity and the expression of mineralization-related genes including ALP, dentin sialophosphoprotein (DSPP), and dentin matrix protein-1 (DMP-1). Also, cell proliferation ability was examined by the 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay. Simultaneously, messenger RNA and protein levels of KLF4 were detected. pKLF4-IRES2-EGFP plasmid encoding full-length KLF4 was constructed to overexpress KLF4, and biologic effects of KLF4 on hDPCs were investigated by the evaluation of ALPase activity and the detection of ALP, DSPP, and DMP-1 expression and analysis of cell proliferation ability.
  
  
  RESULTS
  ALPase activity and the expression of odontoblastic differentiation markers progressively increased in hDPCs cultured with odontoblastic induction medium. Meanwhile, the proliferation ability decreased in this procedure; messenger RNA and protein levels of KLF4 increased significantly on day 5 after the odontoblastic induction of hDPCs and kept increasing until day 14. hDPCs showed up-regulated activity of ALPase and the expression of mineralization-related genes, including ALP, DMP-1, and dentin sialoprotein (DSP), after KLF4 overexpression. Besides, the proliferation ability of hDPCs decreased significantly in the KLF4 overexpression group by EdU incorporation assay.
  
  
  CONCLUSIONS
  Our findings suggest that KLF4 is able to promote odontoblastic differentiation of hDPCs and inhibit proliferation of hDPCs.
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China, 430079.
authors.forename: Heng
authors.initials: H
authors.lastname: Lin
authors.forename: Lili
authors.initials: L
authors.lastname: Xu
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.forename: Qin
authors.initials: Q
authors.lastname: Sun
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Chen
authors.forename: Guohua
authors.initials: G
authors.lastname: Yuan
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D009281:Naphthalenes; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism*; D010082:Oxepins; D012333:RNA, Messenger / Q000032:analysis
chemical_list: C461941:1-phenyl-1,4-epoxy-1H,4H-naphtho(1,8-de)(1,2)dioxepin; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D009281:Naphthalenes; D010082:Oxepins; D012333:RNA, Messenger; D000469:Alkaline Phosphatase