IADR Abstract Archives

The effect of DSP on pulp cell and bone

Objective: Dentin sialophosphoprotein (DSPP) is a dentin-specific non-collagenous matrix protein and post-translationally cleaved into two polypeptides; dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). The mutation in DSPP is associated with dentin defects in human, i.e. dentinogenesis imperfecta (DGI). Since previous reports identified the mutation in human DSP (hDSP) portion (amino acid position at 45) in DGI, we hypothesize that the C-terminal truncated hDSPP protein may cause pulp obliteration observed in these DGI patients. Thus, as a preliminary step toward our hypothesis, the objective of our current study is to characterize the effect of mouse DSP-Q48X (similar to hDSP-Q45X) on pulp cell function and bone formation.

Method: The molecular cloning of mouse DSP (mDSP) DNA was performed by PCR (mDSP-Q48X) and it was subcloned into pGEXT4T-1 bacterial expression vector and mammalian expression vector. The expression of mDSP-Q48X protein was confirmed by Western blot (WB) analysis. The effect of mDSP-Q48X protein addition on pulp cells and calvarial bone was then examined.

Result: The expression of mDSP-Q48X in bacterial expression system and in human embryonic kidney 293 cells was both confirmed and the proteins (purified from bacteria and mammalian cells) did not seem to have any post-translational modification. After GST-mDSP-Q48X protein was purified, GST-mDSP-Q48X protein or GST alone as a control was added into human pulp cells and mouse calvaria ex vivo cultures. DNA synthesis in the pulp cells was increased and bone formation was accelerated.

Conclusion: We successfully generated mDSP-Q48X in expression vector system and purified the protein. Our data highly indicated that this truncated DSP protein has a unique ability to affect cell function and bone formation. The data obtained from this study may provide insights into the biological functions of this particular form of DSP in pulp and bone biology, and help a new molecular design for bone/dental tissue bioengineering.

Division: IADR/LAR General Session
Meeting: 2012 IADR/LAR General Session (Iguaçu Falls, Brazil)
Location: Iguaçu Falls, Brazil
Year: 2012
Final Presentation ID: 327
Abstract Category|Abstract Category(s): Pulp Biology & Regeneration Research

Authors

Jaha, Haytham ( Boston University, Boston, MA, USA )

Ohyama, Yoshio ( Boston University, Boston, MA, USA )

Almehmadi, Ahmed ( Boston University, Boston, MA, USA )

Venkitapathi, Sundharamani ( Boston University, Boston, MA, USA )

Aljamaan, Reem ( Boston University, Boston, MA, USA )

Suzuki, Shigeki ( Hiroshima University, Hiroshima, N/A, Japan )

Mochida, Yoshiyuki ( Boston University, Boston, MA, USA )

Huang, George ( Boston University, Boston, MA, USA )

SESSION INFORMATION

Poster Session
Dental Pulp Cells and Stem Cells
06/21/2012