Xbp1 promotes odontoblastic differentiation through modulating mitochondrial homeostasis

Area of Science:

• Cell Biology
• Developmental Biology
• Genetics

Background:

• Odontoblast differentiation is regulated by transcriptional factors (TFs) and chromatin dynamics.
• The basic leucine zipper (bZIP) TF family plays a role in odontogenesis, but the specific function of XBP1 remains unclear.

Purpose of the Study:

• To investigate the role of XBP1 in odontoblast differentiation during tooth development.
• To identify downstream targets of XBP1 and elucidate its mechanism of action.

Main Methods:

• Stage-specific expression analysis of Xbp1s during tooth development.
• In vitro induction of XBP1 in mesenchymal stem cells (MSCs) using differentiation medium.
• ATAC-seq and RNA-seq to identify XBP1 targets.
• Assessment of odontogenic differentiation potential and mitochondrial homeostasis.

Main Results:

• XBP1 expression and nuclear translocation were induced by differentiation medium in MSCs.
• XBP1 deficiency impaired odontogenic differentiation potential.
• Hspa9 was identified as a direct downstream target of XBP1, crucial for mitochondrial homeostasis.
• Restoring mitochondrial function or overexpressing Hspa9 rescued XBP1-deficient differentiation defects.

Conclusions:

• XBP1 is crucial for odontoblast differentiation by modulating mitochondrial homeostasis.
• This study provides insights into the therapeutic potential for mitochondrial diseases linked to genetic defects.