Figure 10. PTHrP–PPR signalling regulates cell survival, proliferation and differentiation of osterix-expressing dental mesenchymal progenitors through the HDAC4 pathway.

Shown is the concluding summary diagram of this study. First, our findings suggest that PTHrP is predominantly expressed by cells in the dental follicle and root surface, where active cementogenensis takes place. Second, our findings collectively suggest that the PPR signalling in Osx⁺ dental mesenchymal progenitors is important in several critical aspects, such as cell survival, proliferation and differentiation into cementoblasts. Deletion of the PPR signalling in these progenitors leads to defects in survival, proliferation and differentiation of these cells, leading to truncated dental roots and dysregulated cementum formation. Furthermore, HDAC4 appears to be one of the major downstream mediators of the PPR signalling in dental mesenchymal progenitors.