Purpose: To analyze alpha-integrin mediated adhesion of human corneal epithelial cells to placental and EHS laminin isoforms.
Methods: Western blot analysis was used to partially characterize commercially available preparations of laminin isolated from the mouse EHS sarcoma and from human placenta. Using the human corneal epithelial cell line HCE-T, adhesion to laminin isoforms and fibronectin was determined using a colorimetric adhesion assay. alpha-integrin sub-unit modulation of corneal epithelial cell interaction with laminin isoforms was analyzed using immunofluorescence microscopy and adhesion assays incorporating functional blocking antibodies.
Results: In short-term adhesion assays, the preferred substrate for HCE-T attachment is placental laminin. Immunofluorescence microscopy reveals that alpha-integrin protein localization patterns are not significantly different in HCE-T interacting with EHS or placental laminin. However, in short-term assays alpha3 integrin plays a major role, and alpha2 integrin a minor role, in mediating HCE-T adhesion to laminin. alpha6 integrin does not appear to mediate adhesion to either substrate.
Conclusions: These studies demonstrate that human corneal epithelial cells are capable of rapid adhesion to, and enhanced spreading on, laminin isoforms not characteristically resident in the adult corneal basement membrane. This characteristic of human corneal epithelium may explain, at least in part, why amniotic membrane transplantation is proving to be clinically useful for human ocular surface reconstruction.