Abstract
Purpose: :
Corneal epithelial cell adhesion and migration are essential for ocular surface maintenance. Impaired epithelial cell adhesion such as in recurrent corneal erosion syndrome causes severe discomfort and functional disability. Recently, podosomes have been characterized as distinct adhesive domains and putative hemidesmosome precursors in mesenchymal and epithelial cells. We were therefore interested to characterize podosome–like structures in human corneal epithelial cells.
Methods: :
Human corneal epithelial cells (hCEC) were grown as expansion cultures from donor cornea rings and plated on gelatine– or fibronectin–coated glass coverslips. Localization of F–actin, cortactin and vinculin was assessed by confocal immunofluoresecence microscopy. To study the effect of PKC activation, cells were exposed to 1µM phorbol–12,13–dibutyrate (PDBu) for various times.
Results: :
Untreated hCEC formed podosome–like structures at their basal surface. Treatment with PDBu for 10min. markedly increased the number of cells forming podosome–like structures. Within 60min, extensive podosomal networks formed distal to the leading edge of polarized hCEC with concomitant actin cytoskeletal reorganization. The effect of PDBu was more prominent in cells plated on fibronectin than on collagen.
Conclusions: :
Podosome–like structures are formed in hCEC. The localization of PDBu–induced podosomes suggests a role of these structures in cell adhesion and migration and warrants further studies towards their role in hemidesmosome formation.
Keywords: cornea: epithelium • cornea: basic science • pathology: experimental