Abstract
Abstract: :
Purpose: We previously reported gene expression profiling of human corneal and conjunctival epithelial cells whose RNA had been extracted from all epithelial layers. However, better understanding of epithelial cell differentiation processes at the molecular level requires data on active genes obtained from individual epithelial cell layers. We therefore sought to analyze gene expression profiling among epithelial cells from individual layers of the cornea, limbus and conjunctiva. Methods: With a laser micro-dissection device, we separately collected at least 50 human epithelial cells from superficial, intermediate and basal layers of cornea, limbus and conjunctiva. Using mRNAs amplified from each cell group, we examined gene expression profiling among these cells using iAFLP, a kind of competitive RT-PCR, for 400 genes: 200 genes selected from the Bodymap database as corneal epithelium-specific, and 200 genes related to apoptosis, cell adhesion, immune system; some growth hormone receptors etc. Results: The validity of these data was confirmed by similar gene expression of keratin 3/12 in corneal superficial cells, and correspondence of uroplakin 1b gene expression to immunohistochemical localization. Computer-assisted gene cluster analysis showed that all layers of conjunctival epithelial cells were tightly clustered. Although the intermediate and surface layers of cornea and limbus were also tightly clustered, corneal and limbal basal cells showed a distinctive gene expression pattern. Among them, limbal basal cell-specific genes included 6 unknown genes and 2 well-characterized genes (CACL2, FBW2); these genes are good candidates for stem cell markers. Conclusion: The unique gene expression pattern of the limbal basal cell suggests its unique cell function.
Keywords: 370 cornea: basic science • 417 gene/expression • 372 cornea: epithelium