Glycogen synthase kinase 3 inhibition enhances mineral nodule formation by cementoblasts in vitro

Objectives: This study aimed to investigate whether GSK-3 inhibition (CHIR99021) effectively promoted mineralization by cementoblasts (OCCM-30).Materials and MethodsOCCM-30 cells were used and treated with different concentrations of CHIR99021 (2.5, 5 and 10 µM). Experiments included proliferation and viability, cellular metabolic activity, gene expression and mineral nodule formation by Xylene Orange at the experimental time points.ResultsIn general, CHIR99021 did not significantly affect OCCM-30 viability and cell metabolism (MTT assay) (p > 0.05), but increased OCCM-30 proliferation at 2.5 µM on days 2 and 4 (p < 0.05). Data analysis further showed that inhibition of GSK-3 resulted in increased transcript levels of Axin2 in OCCM-30 cells starting as early as 4 h, and regulated the expression of key bone markers including alkaline phosphatase ( Alp ), runt-related transcription factor 2 ( Runx-2 ), osteocalcin ( Ocn ) and osterix ( Osx ). In addition, CHIR99021 led to an enhanced mineral nodule formation in vitro both, under osteogenic and non-osteogenic conditions as early as 5 days after treatment.ConclusionAltogether, the results of the current study suggest that activation of the Wnt signaling by inhibiting GSK-3 has the potential to promote cementoblast differentiation leading to increased mineral deposition in vitro .Clinical relevanceAs cementum regeneration is currently unpredictable due to limited understanding of cementum development, the findings of the present study may lead to new insights into developing more predictable approaches to promote new cementum formation.