Figure 1. Expression of epithelial cell markers in reconstructed hemicorneas. Human corneal epithelial stem cells seeded onto the HKL scaffold form a pluristratified and differentiated epithelium. Cryosections were analyzed through immunofluorescence. The layer of basal cuboidal cells was firmly attached to the underlying extra cellular matrix (ECM) and to the basement membrane through integrins α6 (blue, A), β1 (green, B), and β4 (red, C). The basal expression of p63 isoforms (red, D) and of the stem cell marker ΔNp63α (yellow, E) was always observed, thus suggesting the maintenance of undifferentiated progenitor cells interspersed between differentiated cells. Expression of keratin 14 (green, F) was also observed in the basal layers. Corneal differentiation occurred in all epithelial layers and was evaluated through the analysis of several markers, including 14-3-3σ (pink, G), keratin 19 (orange, H), keratin 3 (yellow, I), and keratin 12 (red, J). Note the presence of the Bowman’s membrane in transmitted-light images (white arrows, D–E). Scale bar=50 μm.