title: Involvement of Wnt activation in the micromechanical vibration-enhanced osteogenic response of osteoblasts.
abstract: BACKGROUND
  Low-magnitude vibration has been widely used as a tool for rehabilitation, enhancing physical performance, and stimulating bone development. Although mechanical stimulation generated by vibrations is regarded as important factor in bone remodeling, the underlying cellular and molecular regulatory mechanisms of this response, which may be important in the development of new mechanobiological strategies, currently remain unclear.
  
  
  METHODS
  In this study, to investigate the mechanobiological mechanisms of vibration-enhanced osteogenic responses in osteoblasts, MC3T3-E1 cells were subjected to vibrations of different amplitude (0.06, 0.14, 0.32, 0.49, 0.66, and 0.8 × g) at 40 Hz for 30 min/day over 3 days. The osteogenesis-related transcription factors Wnt10B, Sclerostin, OPG, and RANKL were analyzed for mRNA and protein expression.
  
  
  RESULTS
  The results revealed that protein expression of Wnt10B and OPG was increased in a magnitude-dependent manner by mechanical vibrations at amplitudes of 0.06, 0.14, 0.32, and 0.49 × g; the maximum increases were 2.4-fold (p < 0.001) and 7.9-fold (p < 0.001), respectively, at 0.49 × g. Sclerostin and RANKL levels were reduced at all amplitudes. On the basis of mRNA levels, the reduced expression of RANKL was further downregulated (p < 0.05) whereas OPG expression was further increased (p < 0.01) when the MC3T3-E1 cells were treated with LiCl compared with the effects of vibration alone.
  
  
  CONCLUSIONS
  The findings may indicate that Wnt signaling is involved in mechanotransduction at low-magnitude vibration; this may provide a cellular basis, and impetus for further development of, biomechanically based intervention for enhancing bone strength and accelerating implant osseointegration.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China. yezi200625@163.com
authors.forename: Wei Wei
authors.initials: WW
authors.lastname: Hou
authors.forename: Zhuo Li
authors.initials: ZL
authors.lastname: Zhu
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: Chun Xiang
authors.initials: CX
authors.lastname: Zhang
authors.forename: Hai Yang
authors.initials: HY
authors.lastname: Yu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D015153:Blotting, Western; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002478:Cells, Cultured; D005819:Genetic Markers; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D010006:Osteoblasts / Q000502:physiology*; D053244:Osteoprotegerin / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D053245:RANK Ligand / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014732:Vibration; D051153:Wnt Proteins / Q000378:metabolism / Q000502:physiology*; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; D053244:Osteoprotegerin; D011518:Proto-Oncogene Proteins; D053245:RANK Ligand; C422903:SOST protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; C491119:WNT10B protein, human; D051153:Wnt Proteins