TGFBI gene transcript is transforming growth factor-beta1-responsive and cell density-dependent in a human corneal epithelial cell line.
OBJECTIVE
To determine the roles of transforming growth factor-beta( 1) (TGF-beta(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-beta(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-beta(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-beta(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.


CONCLUSIONS
The TGFBI gene transcript in this human corneal epithelial cell line is upregulated by growth factor TGF-beta( 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.
Wang
Ming
M
Wang Vision Institute and Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
Munier
Francis
F
Araki-Saski
Kaoru
K
Schorderet
Daniel
D
D015152:Blotting, Northern; D002452:Cell Count; D002455:Cell Division; D002461:Cell Line, Transformed; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D019573:Epithelium, Corneal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation; D000099222:betaIG-H3 Protein
D017931:DNA Primers; D018076:DNA, Complementary; D004815:Epidermal Growth Factor; D016326:Extracellular Matrix Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D000099222:betaIG-H3 Protein; C508960:TGFB1 protein, human