NBCe1 Regulates Odontogenic Differentiation of Human Dental Pulp Stem Cells via NF-κB.

Abstract

Background and objectives: Dental pulp stem cells (DPSCs) play an important role in the repair of tooth injuries. Electrogenic sodium bicarbonate cotransporter 1 (NBCe1) is a Na^＋-coupled HCO₃^- transporter encoded by the solute carrier 4A4 (SLC4A4) gene and plays a crucial role in maintaining the pH of DPSCs. Our previous research confirmed that NBCe1 is highly expressed in odontoblasts during the development of the tooth germ. Therefore, in this study, we aimed to investigate the effect of NBCe1 on odontogenic differentiation of DPSCs and further clarify the underlying mechanisms.

Methods and results: DPSCs were isolated and identified, and the selective NBCe1 inhibitor S0859 was used to treat DPSCs. We used a cell counting Kit-8 assay to detect cell proliferative ability, and intracellular pH was assessed using confocal microscopy. Odontogenic differentiation of DPSCs was analyzed using real-time PCR and Alizarin Red S staining, and the NF-κB pathway was assessed using western blotting. Our results indicated that 10 μM S0859 was the optimal concentration for DPSC induction. Intracellular pH was decreased upon treatment with S0859. The mRNA expressions of DSPP, DMP1, RUNX2, OCN, and OPN were upregulated in the NBCe1 inhibited group compared to the controls. Moreover, NBCe1 inhibition significantly activated the NF-κB pathway, and a NF-κB inhibitor reduced the effect of NBCe1 on DPSC differentiation.

Conclusions: NBCe1 inhibition significantly promotes odontogenic differentiation of DPSCs, and this process may be regulated by activating the NF-κB signaling pathway.