Wnt ligands from the embryonic surface ectoderm regulate 'bimetallic strip' optic cup morphogenesis in mouse

Area of Science:

• Developmental biology
• Ophthalmology
• Molecular biology

Background:

• The Wnt/β-catenin pathway is essential for embryonic development.
• Understanding Wnt signaling's role in eye morphogenesis is critical.

Purpose of the Study:

• To investigate the function of Wnt signaling in early mouse eye development.
• To determine the impact of Wntless deletion on eye structure and cell populations.

Main Methods:

• Conditional deletion of wntless (Wls) in mouse models.
• Microarray analysis and cell fate marker assessment.
• Wnt/β-catenin pathway reporter assays.

Main Results:

• Wls deletion led to optic cup malformations, including ventral coloboma and reduced periocular mesenchyme.
• Gene expression analysis revealed alterations in retinoic acid (RA) and Wnt/β-catenin pathway targets.
• Wnt ligands from the surface ectoderm regulate Wnt/β-catenin signaling in retinal pigment epithelium (RPE) progenitors.

Conclusions:

• Wnt signaling, mediated by Wntless, is vital for normal eye development.
• Reduced RPE cell numbers due to Wnt signaling disruption contribute to optic cup curvature.
• Differential cell numbers in bilayered epithelia can drive tissue shape changes.