A miR-382-5p-PORCN axis modulates endogenous Wnt signaling during palatal development

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Precise temporal control of Wnt signaling is crucial for palate development.
• Mechanisms regulating endogenous Wnt ligand availability during palatogenesis are not well understood.

Purpose of the Study:

• To investigate the role of microRNAs in regulating Wnt signaling during mouse palatogenesis.
• To identify novel regulatory mechanisms controlling Wnt ligand availability.

Main Methods:

• Temporal microRNA profiling of mouse palatal shelves (E13.5-E15.0).
• Bioinformatic analysis to identify microRNA targets.
• Dual-luciferase reporter assays to confirm direct targeting.
• Overexpression of miR-382-5p and assessment of PORCN protein and Wnt signaling markers (Axin2, Ccnd1).
• Rescue experiments using a miRNA-insensitive Porcn construct.

Main Results:

• miR-382-5p showed a transient decrease at embryonic day 14.5, a critical stage for palate development.
• Porcn was identified and confirmed as a direct target of miR-382-5p, with miR-382-5p causing post-transcriptional repression of PORCN.
• Overexpression of miR-382-5p attenuated Wnt signaling, evidenced by reduced target gene expression and reporter activity.
• Restoration of PORCN expression rescued Wnt signaling activity.

Conclusions:

• Porcn is a direct target of miR-382-5p, establishing a novel miR-382-5p-PORCN-Wnt regulatory axis.
• The transient decrease in miR-382-5p during palatogenesis suggests developmental relief of Porcn repression enhances Wnt signaling.
• This pathway contributes to the stage-specific regulation of Wnt signaling essential for palate development.