Oral lining mucosa development depends on mesenchymal microRNAs

Area of Science:

• Developmental Biology
• Molecular Biology
• Oral Biology

Background:

• The oral mucosa, comprising masticatory, lining, and specialized types, has distinct functions and development.
• Molecular mechanisms underlying oral mucosa differentiation are not fully understood.
• MicroRNAs (miRNAs) are key regulators of gene expression, crucial for fine-tuning developmental processes.

Purpose of the Study:

• To investigate the role of mesenchymal microRNAs (miRNAs) in oral mucosa development.
• To elucidate the molecular pathways involved in the differentiation of oral mucosal tissues.

Main Methods:

• Utilized a mouse model with conditional deletion of Dicer in the Wnt1-expressing mesenchymal cells (Wnt1Cre;Dicer(fl/fl)).
• Analyzed the histological and molecular characteristics of the oral mucosa in mutant mice.
• Examined gene expression patterns, focusing on Fibroblast Growth Factor (FGF) signaling.

Main Results:

• Mesenchymal Dicer deletion led to the trans-differentiation of lining mucosa into an epithelium resembling masticatory mucosa and skin.
• Upregulation of FGF signaling was observed in the mutant lining mucosal epithelium.
• Increased Fgf7 expression in the mutant mesenchyme suggests an indirect role of mesenchymal miRNAs in epithelial cell regulation.

Conclusions:

• Mesenchymal microRNAs play a critical, albeit indirect, role in regulating the growth and differentiation of oral lining mucosal epithelium.
• Disruption of miRNA processing in the mesenchyme can induce significant changes in oral mucosal tissue characteristics.
• FGF signaling is implicated as a downstream pathway affected by mesenchymal miRNA dysregulation in oral mucosa development.