title: Asporin in compressed periodontal ligament cells inhibits bone formation.
abstract: OBJECTIVE
  During orthodontic tooth movement, bone resorption and inhibition of bone formation occur on the compressed side, thereby preventing ankylosis. Periodontal ligament (PDL) cells control bone metabolism and inhibition of bone formation on the compressed side by secreting bone-formation inhibitory factors such as asporin (ASPN) or sclerostin (encoded by SOST). The aim of this study was to identify the inhibitory factors of bone formation in PDL cells.
  
  
  METHODS
  In vitro, the changes in expression of ASPN and SOST and subsequent protein release in human PDL (hPDL) cells were assessed by semi-quantitative polymerase chain reaction (PCR), real-time PCR, and immunofluorescence in hPDL cells subjected to centrifugal force using a centrifuge (45, 90, 135, and 160 × g). In vivo, we applied a compressive force using the Waldo method in rats, and examined the distribution of ASPN or sclerostin by immunohistochemistry.
  
  
  RESULTS
  In vitro, hPDL cells subjected to 90 × g for 24h demonstrated upregulated ASPN and downregulated SOST expressions, which were confirmed by immunofluorescent staining. In addition, the formation of mineralized tissue by human osteoblasts was significantly inhibited by the addition of medium from hPDL cells cultured during compressive force as well as the addition of equivalent amounts of ASPN peptide. In vivo, asporin-positive immunoreactive PDL cells and osteoclasts were found on the compressed side, whereas few sclerostin-positive PDL cells were observed.
  
  
  CONCLUSIONS
  PDL cells subjected to an optimal compressive force induce the expression and release of ASPN, which inhibits bone formation during orthodontic tooth movement on the compressed side.
authors.affiliation: Division of Orofacial Functions and Orthodontics, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Masae
authors.initials: M
authors.lastname: Ueda
authors.affiliation: Department of Oral Anatomy and Cell Biology, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan. Electronic address: tgoto@dent.kagoshima-u.ac.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Goto
authors.affiliation: Division of Orofacial Functions and Orthodontics, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Kayoko N
authors.initials: KN
authors.lastname: Kuroishi
authors.affiliation: Division of Orofacial Functions and Orthodontics, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Kaori K
authors.initials: KK
authors.lastname: Gunjigake
authors.affiliation: Division of Orofacial Functions and Orthodontics, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Erina
authors.initials: E
authors.lastname: Ikeda
authors.affiliation: Division of Anatomy, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kataoka
authors.affiliation: Division of Anatomy, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Mitsushiro
authors.initials: M
authors.lastname: Nakatomi
authors.affiliation: Division of Anatomy, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Toyono
authors.affiliation: Division of Anatomy, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Seta
authors.affiliation: Division of Orofacial Functions and Orthodontics, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kawamoto
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000378:metabolism*; D015870:Gene Expression; D005819:Genetic Markers; D006801:Humans; D008297:Male; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques
chemical_list: C439889:ASPN protein, human; D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D016326:Extracellular Matrix Proteins; D005819:Genetic Markers; C422903:SOST protein, human
keywords: Asporin; Compressive force; Orthodontic tooth movement; PLAP-1; Periodontal ligament; Sclerostin