Thiamet-G facilitates reparative dentin formation via modulating O-GlcNAcylation and inflammation.

INTRODUCTION: O-GlcNAcylation, a reversible post-translational modification regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), is involved in various cellular processes, such as proliferation, differentiation, and inflammation modulation. Developmental study revealed that proper O-GlcNAcylation mediated by OGT is vital for tooth morphogenesis. However, the function of O-GlcNAcylation during reparative dentin formation is still unknown. To understand its therapeutic relevance in regenerative dentistry, we examined the potential of OGA inhibitor, Thiamet-G, in reparative dentin formation using both in vitro and in vivo approaches. METHODS: Human dental pulp stem cells were cultivated to examine cell viability, alkaline phosphatase (ALP) activity, and mRNA expression of reparative dentin-related genes. Furthermore, the dental pulp of the upper first molar in 8-week-old male ICR mice was exposed, and Thiamet-G was locally delivered for in vivo studies. Histological and immunohistochemical alterations were analyzed after 3 and 5 days post-cavity preparation, and dentin-bridge formation was evaluated at 42 days using histology and micro-CT. RESULTS: In vitro, Thiamet-G treatment facilitated proliferation, ALP activity, and upregulated expression of reparative dentin-related genes, including BMP2, BSP, DSPP, OCN, and RUNX2. In vivo, Thiamet-G treated specimens showed the altered localizations of NESTIN, NF-κB, MPO, OPN, RUNX2, TGF-β1, and TNF-α at 3 and 5 days post exposure, suggesting enhanced dentin regeneration and modulated inflammation. Particularly, at 42 days, Thiamet-G treated specimens exhibited enhanced dentin-bridge formation, confirmed by micro-CT imaging and histology. CONCLUSION: Thiamet-G treatment facilitated reparative dentin formation by modulating inflammation and regulating regenerating signaling, suggesting its potential as a therapeutic agent.