Abstract
Purpose: :
MicroRNAs (miRNA) are a family of small noncoding, gene regulatory RNAs that control translation of genes by pairing with the 3’UTR sequence of the mRNA coded by the target gene and influence biological processes in the cell, including differentiation. Micro RNAs have shown tissue and stage specificity during development and growth. A number of miRNAs like let7a, 31, 184, 204 and 205 are found in high levels in the eye tissue, especially the corneal epithelium. The purpose of this study was to examine the expression pattern of these five miRNAs during the process of calcium induced differentiation in telomerase immortalized human corneal epithelial cells (hTCEpi).
Methods: :
The expression levels of miRNAs were assayed by qRT-PCR using miRNA specific primers. Differentiation was induced in the cultured cells by growing them in 1.15 mM Ca concentration for 7 days followed by 7 days of airlifting. The cells were then examined for the five miRNAs in undifferentiated and partially differentiated (7 days) and completely differentiated (14 days) stage.
Results: :
The expression levels of miR7a and miR204 showed a study decrease from undifferentiated to completely differentiated cells. However, the levels of miR31, miR184 and miR205 increased by approximately 3 fold for miR31, miR184 and by 4.5 fold for miR205 in partially differentiated cells and to 2 fold in fully differentiated cells.
Conclusions: :
We found that the expression profile of cornea specific miRNAs varies during differentiation of the epithelium. The gene batteries that are controlled by these miRNAs and may be involved in epithelial differentiation are under investigation.
Keywords: cornea: epithelium • differentiation • calcium