title: Effects of the proteasome inhibitor, bortezomib, on cytodifferentiation and mineralization of periodontal ligament cells.
abstract: OBJECTIVE
  The proteasome inhibitor, bortezomib, is known to induce osteoblastic differentiation in a number of cell lines, such as mesenchymal stem cells and osteoblastic precursor cells. As periodontal ligament (PDL) cells are multipotent, we examined whether bortezomib may induce the differentiation of PDL cells into hard-tissue-forming cells.
  
  
  METHODS
  A mouse PDL clone cell line, MPDL22 cells, was cultured in mineralization medium in the presence or absence of bortezomib. Expression of calcification-related genes and calcified-nodule formation were evaluated by real-time PCR and Alizarin Red staining, respectively.
  
  
  RESULTS
  Bortezomib increased the expression of calcification-related mRNAs, such as tissue nonspecific alkaline phosphatase isoenzyme (ALPase), bone sialoprotein (Bsp), runt-related transcription factor 2 (Runx2) and osteopontin, and calcified-nodule formation in MPDL22 cells. These effects were induced, in part, by increasing the cytosolic accumulation and nuclear translocation of β-catenin, leading to an increase in expression of bone morphogenetic protein (Bmp)-2, -4 and -6 mRNAs. In addition, bortezomib enhanced BMP-2-induced expression of Bsp and osteopontin mRNAs and increased calcified-nodule formation in MPDL22 cells.
  
  
  CONCLUSIONS
  Bortezomib induced cytodifferentiation and mineralization of PDL cells by enhancing the accumulation of β-catenin within the cytosol and the nucleus and increasing the expression of Bmp-2, -4 and -6 mRNAs. Moreover, bortezomib enhanced the BMP-2-induced cytodifferentiation and mineralization of PDL cells, suggesting that bortezomib may be efficacious for use in periodontal regeneration therapy.
authors.affiliation: Department of Periodontology, Division of Oral Biology and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan; Challenge to Intractable Oral Diseases, Center for Translational Dental Research, Osaka University Dental Hospital, Suita, Osaka, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kitagaki
authors.forename: S
authors.initials: S
authors.lastname: Miyauchi
authors.forename: C J
authors.initials: CJ
authors.lastname: Xie
authors.forename: M
authors.initials: M
authors.lastname: Yamashita
authors.forename: S
authors.initials: S
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Kitamura
authors.forename: S
authors.initials: S
authors.lastname: Murakami
mesh_terms: D000469:Alkaline Phosphatase / Q000187:drug effects; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000187:drug effects; D055415:Bone Morphogenetic Protein 4 / Q000187:drug effects; D055418:Bone Morphogenetic Protein 6 / Q000187:drug effects; D000069286:Bortezomib / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells / Q000187:drug effects; D050659:Core Binding Factor Alpha 1 Subunit / Q000187:drug effects; D003600:Cytosol / Q000187:drug effects; D007527:Isoenzymes / Q000187:drug effects; D051379:Mice; D053495:Osteopontin / Q000187:drug effects; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D061988:Proteasome Inhibitors / Q000494:pharmacology*; D051176:beta Catenin / Q000187:drug effects
chemical_list: C525719:Bmp2 protein, mouse; C525810:Bmp4 protein, mouse; C525817:Bmp6 protein, mouse; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055418:Bone Morphogenetic Protein 6; C495267:CTNNB1 protein, mouse; D050659:Core Binding Factor Alpha 1 Subunit; D007527:Isoenzymes; D061988:Proteasome Inhibitors; C493716:Runx2 protein, mouse; C506896:Spp1 protein, mouse; D051176:beta Catenin; D053495:Osteopontin; D000069286:Bortezomib; D000469:Alkaline Phosphatase
keywords: bortezomib; cytodifferentiation; mineralization; periodontal ligament