MicroRNA-93-5p regulates odontogenic differentiation and dentin formation via KDM6B

Area of Science:

• Molecular Biology
• Developmental Biology
• Epigenetics

Background:

• Epigenetic factors are crucial for dental pulp stem cell differentiation and tooth development.
• MicroRNAs (miRNAs) can act as epigenetic regulators, influencing factors like DNA methyltransferases and histone modification enzymes.
• MicroRNA-93-5p (miR-93-5p) was identified as differentially expressed during tooth germ development and predicted to target lysine-specific demethylase 6B (KDM6B).

Purpose of the Study:

• To investigate the role of miR-93-5p as an epigenetic regulator (epi-miRNA) in tooth development.
• To elucidate the mechanisms by which miR-93-5p regulates odontogenic differentiation and dentin formation.
• To explore the interaction between miR-93-5p and KDM6B in the context of dental stem cell differentiation.

Main Methods:

• Examined expression patterns of miR-93-5p and KDM6B in dental pulp stem cells (DPSCs) during tooth development and odontogenic differentiation.
• Validated miR-93-5p targeting of KDM6B using dual luciferase reporter and ChIP-qPCR assays in human DPSCs (hDPSCs).
• Assessed the impact of miR-93-5p mimic and inhibitor on hDPSCs' odontogenic differentiation via histological and qPCR analyses.
• Investigated KDM6B-overexpression and miR-93-5p inhibition effects on tertiary dentin formation in a rat pulpotomy model using microCT and histological analyses.

Main Results:

• miR-93-5p expression decreased during odontoblast differentiation, inversely correlating with increased KDM6B expression.
• Overexpression of miR-93-5p inhibited hDPSCs' odontogenic differentiation, while inhibition promoted it.
• miR-93-5p directly targets the 3' UTR of KDM6B, suppressing its protein translation.
• KDM6B demethylated H3K27me3 marks at BMP2 promoters, upregulating BMP2 transcription.
• In vivo, KDM6B-overexpression or miR-93-5p inhibition promoted tertiary dentin formation by reducing H3K27me3 levels in DPSCs.

Conclusions:

• miR-93-5p acts as an epi-miRNA by targeting the epigenetic regulator KDM6B.
• This interaction modulates H3K27me3 marks on BMP2 promoters, thereby influencing odontogenic differentiation of DPSCs.
• The miR-93-5p/KDM6B axis plays a significant role in dentin formation, presenting a potential therapeutic target for dental regeneration.