Ectodermal Wnt controls nasal pit morphogenesis through modulation of the BMP/FGF/JNK signaling axis

Area of Science:

• Developmental biology
• Molecular genetics
• Craniofacial development

Background:

• WNT gene mutations are linked to orofacial birth defects like cleft lip and palate.
• The origin and function of Wnt ligands in facial development are not fully understood.

Purpose of the Study:

• To investigate the role of Wnt secretion in nasal-facial development.
• To identify the source of Wnt ligands during facial morphogenesis.

Main Methods:

• Utilized Foxg1-Cre to inactivate Gpr177/mWls, impairing Wnt secretion.
• Analyzed effects of Gpr177 ablation on facial development, cell proliferation, death, and cell migration.

Main Results:

• Gpr177 ablation in ectoderm caused severe facial deformities.
• Reduced cell proliferation and increased cell death observed due to WNT, FGF, and BMP signaling loss.
• Impaired olfactory epithelial cell migration and altered JNK signaling.

Conclusions:

• Head ectoderm (facial and neuroectoderm) is identified as the source of Wnt ligands.
• Both β-catenin-dependent and -independent Wnt pathways are essential for nasal-facial development.