Sclerostin Promotes Bone Remodeling in the Process of Tooth Movement

PLoS One. 2017 Jan 12;12(1):e0167312. doi: 10.1371/journal.pone.0167312. eCollection 2017.

Abstract

Tooth movement is a biological process of bone remodeling induced by mechanical force. Sclerostin secreted by osteocytes is mechanosensory and important in bone remodeling. However, little is known regarding the role of sclerostin in tooth movement. In this study, models of experimental tooth movement were established in rats and mice. Sclerostin expression was investigated with immunohistochemistry staining, and osteoclastic activity was analyzed with tartrate-resistant acid phosphatase (TRAP) staining. MLO-Y4 osteocyte-like cells underwent uniaxial compression and tension stress or were cultured in hypoxia conditions. Expression of sclerostin was assessed by RT-qPCR and ELISA. MLO-Y4 cells were cultured with recombinant human sclerostin (rhSCL) interference and then co-cultured with RAW264.7 osteoclast precursor cells. Expressions of RANKL and OPG were analyzed by RT-qPCR, and osteoclastic activity was assessed by TRAP staining. During tooth movement, sclerostin was expressed differently in compression and tension sites. In SOST knock-out mice, there were significantly fewer TRAP-positive cells than in WT mice during tooth movement in compression sites. In-vitro studies showed that the expression of sclerostin in MLO-Y4 osteocyte-like cells was not different under a uniaxial compression and tension force, whereas hypoxia conditions significantly increased sclerostin expression in MLO-Y4 cells. rhSCL interference increased the expression of RANKL and the RANKL/OPG ratio in MLO-Y4 cells and the osteoclastic induction ability of MLO-Y4 cells in experimental osteocyte-osteoclast co-culture. These data suggest that sclerostin plays an important role in the bone remodeling of tooth movement.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Bone Morphogenetic Proteins / metabolism*
  • Bone Morphogenetic Proteins / pharmacology
  • Bone Remodeling / drug effects
  • Bone Remodeling / physiology*
  • Cell Hypoxia
  • Cell Line
  • Genetic Markers
  • Glycoproteins / metabolism*
  • Glycoproteins / pharmacology
  • Humans
  • Intercellular Signaling Peptides and Proteins
  • Male
  • Mice
  • Osteocytes / metabolism*
  • Osteoprotegerin / metabolism
  • RANK Ligand / metabolism
  • RAW 264.7 Cells
  • Rats
  • Rats, Sprague-Dawley
  • Tartrate-Resistant Acid Phosphatase / metabolism
  • Tooth Mobility / metabolism*
  • Tooth Movement Techniques

Substances

  • Adaptor Proteins, Signal Transducing
  • Bone Morphogenetic Proteins
  • Genetic Markers
  • Glycoproteins
  • Intercellular Signaling Peptides and Proteins
  • Osteoprotegerin
  • RANK Ligand
  • SOST protein, human
  • Sost protein, mouse
  • Sost protein, rat
  • Tnfrsf11b protein, mouse
  • Tnfrsf11b protein, rat
  • Tnfsf11 protein, mouse
  • ACP5 protein, human
  • Acp5 protein, mouse
  • Tartrate-Resistant Acid Phosphatase

Grants and funding

This study was supported by National Natural Science Foundation of China (Grant No. 11172190 (received by Ding), 81371171 (received by Ding), 81371172 (received by Xianglong) and 81500885 (received by Rui)) and Research Fund for the Doctoral Program of Higher Education of China, Grant No. 20130181110013 (received by Ding). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.