NBCe1 in mouse and human ameloblasts may be indirectly regulated by fluoride

Area of Science:

• Biomineralization
• Tooth enamel formation
• Cellular pH regulation

Background:

• Enamel biomineralization releases protons, acidifying the local microenvironment.
• This acidification can be exacerbated by fluoride, requiring neutralization by ameloblasts.
• The electrogenic sodium bicarbonate co-transporter 1 (NBCe1) is implicated in ameloblast pH regulation.

Purpose of the Study:

• To investigate the role of NBCe1 in ameloblast pH regulation during enamel formation.
• To determine NBCe1 expression patterns in human and mouse ameloblasts.
• To assess the impact of fluoride and low pH on NBCe1 expression.

Main Methods:

• Transcript analysis using PCR and quantitative PCR (qPCR).
• In situ hybridization to localize NBCe1 mRNA.
• In vitro studies using human ameloblast-lineage cells.
• In vivo studies in mice with controlled fluoride ingestion.

Main Results:

• NBCe1-A found in human ameloblasts; NBCe1-B in mouse ameloblasts.
• NBCe1 mRNA levels increased with ameloblast differentiation in both species.
• Fluoride ingestion upregulated NBCe1 mRNA in maturation-stage mouse ameloblasts.
• Low pH upregulated NBCe1 in vitro, but fluoride did not.

Conclusions:

• NBCe1 plays a role in modulating pH during enamel formation.
• Fluoride-induced acidification in vivo may lead to NBCe1 upregulation.
• NBCe1 is crucial for maintaining pH homeostasis in the developing enamel matrix.