The synergistic effects of TGF- β1 and RUNX2 on enamel mineralization through regulating ODAPH expression during the maturation stage

In this study,TGF- β1−/−Runx2−/− andTGF- β1+/ −Runx2+/ − mice were successfully generated to clarify the relationship between TGF- β1 and RUNX2 during amelogenesis. Lower mineralization was observed inTGF- β1−/−Runx2−/− andTGF- β1+/ −Runx2+/ − mice than single gene deficient mice. Micro-computed tomography ( μCT) revealed a lower ratio of enamel to dentin density inTGF- β1−/−Runx2−/− mice. Although μCT elucidated a relatively constant enamel thickness, variation was identified by scanning electron microscopy, which revealed thatTGF- β1−/−Runx2−/− mice were more vulnerable to acid etching with lower degree of enamel mineralization. Furthermore, the double gene knock-out mice exhibited more serious enamel dysplasia than the single gene deficient mice. Hematoxylin –eosin staining revealed abnormalities in ameloblast morphology and arrangement inTGF- β1−/−Runx2−/− mice, which was accompanied by the absence of atypical basal lamina (BL) and the ectopic of enamel matrix. Odontogenesis-associated phosphoprotein (ODAPH) has been identified as a component of an atypical BL. The protein and mRNA expression of ODAPH were down-regulated. In summary, TGF- β1 and RUNX2 might synergistically regulate enamel mineralization through the downstream target geneOdaph. However, the specific mechanism by which TGF- β1 and RUNX2 promote mineralization remains to be further studied.
Source: Journal of Molecular Histology - Category: Laboratory Medicine Source Type: research