Abstract

DO.14.01

Expression of pluripotency/multipotency markers in human corneal, limbal and cultivated limbal epithelium

Mikk Pauklin, Anne Pester, Henning Thomasen, Sabah Brockmann-Ahmed, Klaus-Peter Steuhl, Daniel Meller
Zentrum für Augenheilkunde, Universitätsklinikum Essen, Essen

Objective
Corneal epithelial stem cells (SC) are located in the limbal zone. Recent studies have shown that several adult stem cells express pluripotency markers and can under certain conditions differentiate into a wide range of cell types. The objective of this study was to analyze the expression of key molecules needed for the maintenance of pluripotency in the human corneal and limbal epithelium, as well as in cultivated limbal epithelium.
Methods
Four samples of human corneal, limbal and on intact amniotic membrane cultivated limbal epithelium were analyzed. The expression of corneal epithelial differentiation markers (K3, K12, K15 and Cx43), putative limbal SC markers (ABCG2, p63), and molecules needed for pluripotency/multipotency (NANOG, OCT4 (POU5F1), SOX2, KLF4, KIT, NESTIN, PAX6) was examined using Real-Time PCR and immunohistochemical staining.
Results
The expression of all studied markers was detected in all limbal and corneal epithelial samples. Limbal epithelium showed a significantly (p<0.05) higher expression of K15, ABCG2, OCT4, SOX2, and NESTIN, but a significantly lower expression of K3 in comparison to central corneal epithelium. Limbal epithelial cells did not express K3 after cultivation on amniotic membrane and showed a significantly lower expression of differentiation markers K12 and Cx43 in comparison to both corneal and limbal epithelium. The expression of all pluripotency markers was detectable in cultivated limbal epithelial cells, even though the expression was significantly lower than in native limbal epithelium.
Conclusions
The human limbal epithelial cells express genes that are associated with the maintenance of pluripotency/multipotency and preserve an expression of these genes even after cultivation on amniotic membrane. Limbal epithelial stem cells may have a higher differentiation potential than previously presumed.

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