Abstract
Purpose: :
Human corneal epithelium is regenerative through the proliferation and migration of corneal epithelial progenitor cells residing in the basal epithelium of limbus. In this study, we characterized the microRNA expression pattern of human limbal-peripheral corneal epithelium (LPC) compared with central corneal epithelium (CC), and the potential regulatory routes involved in corneal epithelium formation and development.
Methods: :
Human MicroRNA Microarray and qPCR was performed to detect microRNA profiling in LPC and CC. Based on the known similar expression levels of hsa-miR-205, differentially expressed microRNAs were identified. Functional annotation analysis of predicted microRNA targets was performed with Database for Annotation, Visualization and Integrated Discovery (DAVID) version 6.7 and significant cross-correlated pathways were compared.
Results: :
Eighteen microRNAs were differentially expressed in human LPC and CC epithelia. Among them, 14 were up-regulated in LPC, and the remaining 4 vice versa. By microRNA-mRNA association, the algorithmic targets of these microRNAs included the reported limbal progenitor-enriched genes (ABCG2, TP63, BMI-1, and EGFR), limbal basal cell-expressing transcription factor TCF4, proliferation-related genes (CTNNB1, CCND family), corneal differentiation proteins (KRT3, CDH2, SPRR family), neurotrophic factor GDNF and its receptor GFRA1. Gene ontology (GO) analysis of predicted targets of LPC up-regulated microRNAs identified statistically enriched functional categories, such as cell proliferation, cell cycle, stem cell development, regulation of epithelial cell differentiation, wound healing and eye development. Whereas, CC up-regulated microRNAs have significant GO terms related with terminal differentiation events such as apoptosis, cell-cell signaling, cell migration and hormone secretion.
Conclusions: :
Our study has identified the unique microRNA expression patterns in human corneal epithelium and suggests the importance of microRNAs in cornea homeostasis and differentiation.
Keywords: cornea: epithelium • gene microarray • cornea: basic science