| 0592 BMP-2 Induction of DSPP and Odontoblast Differentiation through Osx | ||
|
J.M. GONZALEZ1, T. LI1, J.G. HEINRICH1, Y. WU1, H. CHUANG1, K. DONLY1, J. DONG2, I. GAY2, M. MACDOUGALL2, and S. CHEN1, 1University of Texas - San Antonio / Health Science Ctr, USA, 2University of Alabama at Birmingham, USA Bone morphogenetic protein-2 (BMP-2) is a potent secreted factor that stimulates osteoblast and dental cell differentiation. BMP-2 induces cell fate presumably by activating specific target gene expression. Dentin sialophosphoprotein (DSPP) is one of key markers during odontoblast differentiation and dentinogensis. However, the signaling pathway of BMP-2 related to DSPP expression during odontoblast cytodifferentiation remains unclear. Objective: To investigate downstream gene(s) of BMP-2 signaling on DSPP gene expression in mouse odontoblasts. Methods: The mouse odontoblast cell line (MO6-G3) was treated with recombinant BMP-2 (100 ng/ml) for 12 h, 24 h, 48 h and 72 h, respectively. Quantitative real time qRT-PCR and fluorescent immunohistochemistry were used to measure expression of DSPP and other related bone/tooth genes in BMP-2 treated and non-treated control cells. Transient transfection and electrophoretic mobility shift analyses were performed to determine the BMP-2 response element(s) in the mouse DSPP promoter and transcription factors binding to these elements. In situ hybridization assay was carried out to determine expression of DSPP and identified key transcription factors during tooth development. Results: BMP-2 treatment of MO6-G3 cells up-regulated the DSPP expression and the transcription factor Osterix (Osx/Sp7) at the mRNA and protein levels as determined by qRT-PCR and immunohistochemistry. Osx, a zinc finger transcription factor, is essential for osteoblast and odontoblast differentiation since Osx null mice have arrested bone and tooth formation. In situ hybridization analysis showed that both DSPP and Osx gene expressions are gradually increased with odontoblast cytodifferentiation. An Osx binding site capable of binding Osx was identified located in the proximal region of the mouse DSPP promoter. Conclusions: This study demonstrates that BMP-2 mediates DSPP expression during dentinogenesis mediated through the Osx signaling pathway. Detail mechanisms of this signaling pathway are yet to be determined. This study was supported by NIDCR grants DE14318 (CO-STAR) and P01 DE 13221 (MM) | ||
| Seq #87 - Cell differentiation 2:00 PM-3:15 PM, Thursday, March 22, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J | ||
|
Back to the Mineralized Tissue Program
| ||