Purpose: To determine the roles of transforming growth factor-ß 1 (TGF-ß 1 ), epidermal growth factor (EGF), and cell density on the regulation of the TGFBI gene transcript in a human corneal epithelial cell line (HCE-T). Methods: HCE-T cells (40–50% confluent), which possess the biochemical and morphological phenotype of human corneal epithelial cells, were treated with either TGF-ß 1 (20 ng/ml) or EGF (20 ng/ml) for 0, 24, 48, and 72 h. Total RNA was isolated at each time point from the treated cells and the placebo-treated controls. The TGFBI mRNA transcript level was quantitated using Northern blot analysis. Results: TGF-ß 1 upregulates TGFBI gene transcript in this human corneal epithelial cell line, reaching a peak of 2.5-fold of upregulation at 48 h after TGF-ß 1 treatment and a 1.5-fold at 72 h. In contrast, EGF treatment showed no effect on the TGFBI mRNA level. In addition, the TGFBI gene transcript appears to be cell density-dependent because the transcript level shows a trend of reduction as the cell density increases from 40–50% to full confluency. Conclusion: The TGFBI gene transcript in this human corneal epithelial cell line is upregulated by growth factor TGF-ß 1 , but is not affected by growth factor EGF. Furthermore, cell density appears to be an important regulatory mechanism in controlling the level of TGFBI gene expression in corneal epithelial cells.

Read More: http://informahealthcare.com/doi/abs/10.1076/opge.23.4.237.13884