Hongyou Yu

Publications (3)3.62 Total impact

• Article: Overexpression of osteoprotegerin promotes preosteoblast differentiation to mature osteoblasts.

  Hongyou Yu, Paul de Vos, Yijin Ren
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  ABSTRACT: The hypothesis of the present study is that overexpression of osteoprotegerin (OPG) promotes preosteoblast maturation. The preosteoblast cell line MC3T3-E1 was transfected with OPG overexpression. OPG expression was confirmed by enzyme-linked immunosorbent assay (ELISA) and Western blot. Changes in the transcription factors in OPG-expressing cells were assessed by real-time polymerase quantitative polymerase chain reaction (RT-qPCR). Alkaline phosphate (ALP) expression was measured by ELISA. The success of stable transfection of MC3T3-E1 cells with OPG overexpression was confirmed by MoFlow sorting followed by G418 selection. RT-qPCR showed that expression of RunX2, the most important osteoblast differentiation controlling factor, was suppressed. Smad1 and Akt1, as well as ALP, were upregulated in the OPG overexpressing cells. Results from the present study provide evidence that overexpression of OPG in preosteoblasts promotes its differentiation into mature osteoblasts.
  The Angle Orthodontist 01/2011; 81(1):100-106. · 1.21 Impact Factor
• Article: Orthodontic mechanical tension effects on the myofibroblast expression of alpha-smooth muscle actin.

  Yao Meng, Xianglong Han, Lan Huang, Ding Bai, Hongyou Yu, Yan He, Yan Jing
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  ABSTRACT: To detect myofibroblast formation on the tension side during orthodontic tooth movement in vivo and myofibroblast expression of alpha-smooth muscle actin (alpha-SMA) induced by tension both in vivo and in vitro. Fifty 6-week male rats were used in this in vivo study, and the right maxillary first molar was moved mesially, which served as the experimental group, and the left maxillary first molar served as the control. Rats were sacrificed at days 0, 3, 5, 7, and 14 after force loading. Myofibroblasts, identified with alpha-SMA, were examined through immunohistochemistry. For the in vitro study, human periodontal ligament (PDL) fibroblasts were obtained. Cyclic mechanical tension was applied to the fibroblasts for 0, 1, 3, 6, and 12 hours. Transmission electron microscopy was used to detect the ultrastructure of myofibroblasts. alpha-SMA mRNA gene expression was quantified by real-time quantitative PCR. The expression of alpha-SMA was detected by immunofluorescence and quantified by Western blotting. In vivo, the myofibroblasts expressing alpha-SMA were identified both in the experimental group and in the control group. The expressions of alpha-SMA were increased in the tension areas of the experimental group over time, and reached the maximum in day 14. In vitro, fibronexus junctions and actin microfilaments in the cells could be found with transmission electron microscopy. Cyclic mechanical tension could significantly induce alpha-SMA expression at 12 hours (P < .01) than the controls. Myofibroblasts existed in the PDL. The expressions of alpha-SMA in the myofibroblasts were significantly up regulated under tension both in vivo and in vitro.
  The Angle Orthodontist 09/2010; 80(5):912-8. · 1.21 Impact Factor
• Article: Mechanical tensile stress effects on the expression of bone sialoprotein in bovine cementoblasts.

  Hongyou Yu, Yijin Ren, Andrew Sandham, Aishu Ren, Lan Huang, Ding Bai
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  ABSTRACT: To develop a new cementoblast culture method and to detect bone sialoprotein (BSP) expression in response to high and low mechanical tensile stress in cementoblast in vitro. Cementoblasts were collected from the roots of newborn bovine teeth and were identified with cementum-derived attachment protein (CAP) antibody 3G9. Cell proliferation was evaluated by MTT [3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay, and mineralization was confirmed by von Kossa staining. Mechanical tensile stress was applied in vitro to the cementoblast with the use of a uniaxial four-point bending system with 2000 or 4000 microstrains, at a frequency of 0.5 Hz for 3, 6, 12, 24, or 36 hours. BSP mRNA level was quantified by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). A large amount of cementoblast was observed to be expressing CAP. Cementoblasts had a proliferation tendency similar to that of osteoblasts but different from that of periodontal ligament (PDL) cells. Cementoblasts had the ability to become mineralized between osteoblasts and PDL cells. The mechanical tensile stress significantly up-regulated BSP mRNA expression, which reached a peak at 24 hours in both 2000 and 4000 microstrain groups (P < .01) and was tenfold and sixfold higher than that of controls, respectively. BSP expression dropped toward baseline levels at 36 hours in both groups. Mechanical tensile stress up-regulated the expression of BSP. Low mechanical tensile stress induced earlier and more intensive up-regulation of BSP mRNA; this might represent the optimal stimuli for cementoblast activity.
  The Angle Orthodontist 03/2009; 79(2):346-52. · 1.21 Impact Factor