Multiple roles of Pax6 in postnatal cornea development

Area of Science:

• Developmental Biology
• Ophthalmology
• Cell Biology

Background:

• Mammalian corneal development involves complex epithelial, endothelial, and stromal formation.
• Postnatal corneal epithelium undergoes stratification and continuous renewal.
• Pax6 is a key transcription factor in ocular development.

Purpose of the Study:

• To investigate the role of Pax6 in mammalian corneal development and differentiation.
• To determine Pax6's function in ocular surface epithelium (OSE) and postnatal corneal epithelium (CE) using conditional depletion.

Main Methods:

• Utilized the Cre-loxP system for conditional depletion of Pax6 in K14-cre (OSE) and Aldh3-cre (postnatal CE) expressing cells.
• Employed immunofluorescence studies to analyze protein expression, including cytokeratins and junctional proteins (Zonula occludens-1).

Main Results:

• Early Pax6 inactivation in OSE caused thickened epithelium with conjunctival keratinization in corneal and limbal cells.
• Postnatal Pax6 depletion in CE led to reduced epithelial thickness, increased proliferation, loss of Cytokeratin 12, and impaired cell adhesion.
• Aberrant Cytokeratin 14 expression in apical layers indicated defective corneal epithelial cell differentiation.

Conclusions:

• Pax6 is essential for maintaining postnatal corneal epithelial differentiation and intercellular adhesion.
• Pax6 in the limbus prevents conjunctival cell overgrowth onto the cornea.
• Conditional Pax6 depletion reveals its critical roles in distinct ocular surface compartments.