PURPOSE. Congenital aniridia due to heterozygosity for Pax6 is associated with ocular surface disease, including keratopathy. This study investigated how defects in glycoconjugate component of the cell surface of Pax6(+/-) could cause the abnormal cellular migration phenotypes associated with the disease.
METHODS. Immunohistochemistry, lectin-based histochemistry, conventional staining techniques, and proteomic assays were performed on eyes and cultured corneal epithelial cells from wild-type and Pax6(+/-) littermates. Wild-type cells were manipulated in culture to replicate the glycoconjugate abnormalities found in Pax6 heterozygotes and determine the consequences for wound healing.
RESULTS. Multiple glycoconjugate defects were found in Pax6-mutant cells. Lectin cytochemistry of corneal epithelial cells suggested a partial failure of glycoprotein trafficking. Blocking cell surface carbohydrate moieties in wild-type corneal cells caused wound-healing delays similar to those seen in untreated Pax6(+/-) cells.
CONCLUSIONS. Alterations to the cell surface glycoconjugate signature of Pax6(+/-) corneal epithelia restrict the ability of cells to initiate migration in response to wounding. This underlies the observed wound-healing delay in cultured Pax6(+/-) epithelia.
- metalloproteinase gelatinase B
- heparan-sulfate proteoglycans