Cytoskeletal and cell adhesion defects in wounded and Pax6+/- corneal epithelia

Area of Science:

• Ophthalmology
• Genetics
• Cell Biology

Background:

• PAX6 heterozygosity (PAX6(+/-)) causes aniridia and aniridia-related keratopathy (ARK).
• The molecular mechanisms linking PAX6 gene dosage deficiency to corneal disease remain incompletely understood.
• Previous studies suggest a chronic wound state and compromised barrier function in Pax6(+/-) corneas.

Purpose of the Study:

• To investigate the cellular and molecular basis of corneal defects in Pax6(+/-) mice.
• To characterize the cytoskeletal and wound-healing phenotypes in Pax6(+/-) corneas.
• To elucidate the contribution of these phenotypes to the pathogenesis of ARK.

Main Methods:

• Utilized Pax6(+/-) mice as a model for Pax6-related corneal diseases.
• Performed in vivo wound-healing assays on wild-type and Pax6(+/-) corneas.
• Conducted immunohistochemistry and electron microscopy to analyze cellular structures and molecular markers.

Main Results:

• Identified defects in keratin, desmoplakin, and actin cytoskeletal organization in Pax6(+/-) corneal cells.
• Observed phenotypes in unwounded Pax6(+/-) corneas (e.g., cell fissures, vesicles, gaps) similar to wounded wild-type corneas.
• Detected increased protein oxidation and MAPK phosphorylation (ERK1/2, p38) in Pax6(+/-) corneal epithelia, indicative of a wound-healing response.

Conclusions:

• Cell junctions and cytoskeleton are dynamically remodeled in Pax6(+/-) corneas, resembling a wound-healing state.
• These dynamic cellular changes contribute to the clinical manifestations of aniridia-related keratopathy (ARK).
• The findings provide insights into the pathogenesis of corneal diseases associated with PAX6 mutations.