The extracellular matrix of the developing cornea: diversity, deposition and function

Area of Science:

• Ophthalmology
• Developmental Biology
• Biochemistry

Background:

• The cornea's transparency relies on its organized extracellular matrix (ECM).
• Neural crest (NC) cells differentiate into corneal endothelium and fibroblasts.
• The ocular ECM's role in this differentiation is under investigation.

Purpose of the Study:

• To examine the role of ECM components, particularly collagen I and proteoglycans, in corneal development and stromal morphogenesis.
• To investigate the unique processes of fibrillogenesis in the corneal stroma.

Main Methods:

• Comparative analysis of normal corneas and collagen I-deficient Mov13 mouse corneas.
• In vitro studies using chick corneal epithelia with intact basal lamina to assess stromal deposition.
• Enzymatic degradation of chondroitin sulfate (CS) to evaluate its role in morphogenesis.

Main Results:

• Collagen I is essential for structural integrity and proper fibril organization in the corneal stroma, though its absence doesn't alter initial cellular morphology.
• Corneal epithelial production of collagen and proteoglycans is largely independent of the substratum.
• Chondroitin sulfate (CS) does not appear essential for stromal morphogenesis but may function as a lubricant for corneal growth.
• Corneal stromal fibrillogenesis differs from other embryonic tissues, possibly due to an unidentified ECM macromolecule.

Conclusions:

• Collagen I plays a critical structural role in corneal stromal organization.
• Corneal stromal development exhibits a degree of epithelial autonomy.
• Chondroitin sulfate's primary role may be facilitating corneal growth through lubrication.
• Unique ECM components likely govern corneal fibrillogenesis, distinguishing it from other developmental contexts.