Dexamethasone Suppresses Palatal Cell Proliferation through miR-130a-3p

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Cleft lip with or without cleft palate (CL/P) is a common congenital birth defect.
• MicroRNAs (miRNAs) are critical regulators of gene expression and play roles in embryonic development.

Purpose of the Study:

• To identify novel pathogenic microRNAs associated with cleft palate (CP).
• To investigate the role of specific microRNAs in dexamethasone-induced CP in mice.

Main Methods:

• miRNA-sequencing of developing mouse palatal shelves at different embryonic stages (E13.5 vs. E14.5).
• In vitro studies using primary mouse embryonic palatal mesenchymal (MEPM) cells and O9-1 neural crest cells to assess the functional impact of miRNA manipulation.
• Dexamethasone treatment to induce CP in mice and subsequent analysis of miRNA expression and cellular effects.

Main Results:

• Several miRNAs were found to be significantly upregulated (miR-449 family) or downregulated (miR-19a-3p, miR-130a-3p, miR-301a-3p, miR-486b-5p) during palate development.
• Overexpression of miR-449 family members and miR-486b-5p, and inhibition of miR-130a-3p and miR-301a-3p, affected cell proliferation in MEPM and O9-1 cells.
• Dexamethasone suppressed miR-130a-3p expression, and a miR-130a-3p mimic counteracted dexamethasone's effect on cell proliferation and normalized Slc24a2 expression.

Conclusions:

• The miR-449 family and miR-486b-5p may play roles in normal palate development by regulating cell proliferation.
• miR-130a-3p is crucial in the pathogenesis of dexamethasone-induced cleft palate in mice, potentially by regulating Slc24a2 expression.