title: Hypoxia-inducible factor-1α is required for transforming growth factor-β1-induced type I collagen, periostin and α-smooth muscle actin expression in human periodontal ligament cells.
abstract: BACKGROUND
  We reported previously that hypoxia inducible factor (HIF)-1α was not degraded under normoxic condition with transforming growth factor (TGF)-β1 stimulation in human periodontal ligament (PDL) cells; however, the role of HIF-1α has been unclear. Recently, HIF-1α, working together with TGF-β1, has been reported to promote extracellular matrix accumulation under normoxic condition in renal epithelial cell. The aim of this study is to investigate the effects of HIF-1α on the expression of TGF-β1-mediated genes including type I collagen, periostin and α-smooth muscle actin (SMA) in human PDL cells.
  
  
  METHODS
  The effects of TGF-β1 on HIF-1α mRNA and protein expression were analyzed by real-time RT-PCR and western blot, respectively. Next, The expression of type I collagen, periostin and α-SMA mRNA were analyzed with or without HIF-1α under normoxic condition with TGF-β1 stimulation using a real-time RT-PCR.
  
  
  RESULTS
  TGF-β1 induced the expression of HIF-1α both in mRNA and protein levels. TGF-β1-induced mRNA expression of type I collagen, periostin and α-SMA were inhibited even with TGF-β1 stimulation when HIF-1α was knocked down.
  
  
  CONCLUSIONS
  HIF-1α is required for TGF-β1-induced type I collagen, periostin and α-SMA expression in human PDL cells.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan. Electronic address: teppei@dent.tokushima-u.ac.jp.
authors.forename: Teppei
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yasue
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Tanaka
mesh_terms: D000199:Actins / Q000378:metabolism; D001641:Bicuspid; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000378:metabolism; D018929:Cell Culture Techniques; D024042:Collagen Type I / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D009130:Muscle, Smooth / Q000378:metabolism; D010513:Periodontal Ligament / Q000166:cytology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D000199:Actins; D015815:Cell Adhesion Molecules; D024042:Collagen Type I; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C512835:POSTN protein, human; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta
keywords: HIF-1α; Periodontal ligament cells; TGF-β1