Abstract
Abstract: :
Purpose:The human cornea expresses three isoforms of TGF-ß(ß1, ß2, and ß3), but the specific roles among the isoforms on the regulation of epithelial proliferation as well as their functional differences during the process of wound healing in the corneal epithelium have not been fully elucidated. It has been shown that mRNA of TGF-ß2 is more strongly expressed than those of ß1 and ß3 in the corneal epithelium. In addition, human tears contain TGF-ß2 abundantly. Our previous study using the cDNAexpression array system demonstrated that TGF-ß1 affected the expression levels of specific genes, not only at the mRNA level but also at the protein expression level. In this study, we report on our investigation of the effect of TGF-ß2 on the simultaneous expression of many genes in cultured human corneal epithelial cells (HCECs) with cDNA array system. Methods:Human cDNA expression array technology was used to study the simultaneous expression of 1176 cellular genes in HCECs incubated with TGF-ß2(10ng/ml) for 12 hr. cDNA probes were obtained from untreated and TGF-ß2 treated HCECs. Results:TGF-ß2 treatment caused an increase in the expression level of 67genes such as NDP kinase B, c-myc oncogene, cyclin K, MAP kinase3, transcription factor AP-1 and erythrocyte glucose transporter 1. The expression of 184 genes including the vav oncogene, MPP2 protein, erythropoietithin receptor, p53 cellular tumor antigen and stem cell tyrosine kinase 1 was downregulated. The types of genes influenced by TGF-ß2 were significantly different from those of TGF-ß1. Conclusion:TGF-ß2, like TGF-ß1, has a strong effect on the regulation of genes in the corneal epithelium. Each isoform of TGF-ßs plays a unique role in the control of epithelia during wound healing. Since TGF-ß2 tends to decrease the expression of genes, it may act as a negative regulator of cellular proliferation in the cornea. The cDNA expression array provides novel information for the clarification of the cascade of TGF-beta-induced cell signal transduction.
Keywords: 372 cornea: epithelium • 417 gene/expression • 423 growth factors/growth factor receptors