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H. Nakamura, J. Sugar, B.Y. Yue; Influence of Cytokines on Levels of Transcription Factor Sp1 in Cultures of Human Corneal Fibroblasts . Invest. Ophthalmol. Vis. Sci. 2003;44(13):849.
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Purpose: Transcription factor Sp1 has been implicated in the activation or suppression of a large number of genes. The purpose of this study was to determine whether cytokines such as interleukin-1 (IL-1) α and ß can modulate the expression of Sp1 in cultures of normal human corneal fibroblasts. Methods: Early passaged human corneal fibroblasts were treated for 24 or 48 hours with cytokines including IL-1α and ß (10 ng/ml), epidermal growth factor (EGF, 15 ng/ml), fibroblast growth factor-2 (FGF-2, 20 ng/ml), and transforming growth factor ß1 and ß2 (10 ng/ml) in serum-free medium. The cells were either fixed for immunohistochemical evaluation of Sp1 level or harvested for nuclear extraction and Western blotting. Results: The Sp1 nuclear staining in corneal fibroblasts was enhanced by all the cytokines studied. The enhancement was most dramatically observed with EGF and FGF-2. Western blot analyses confirmed the immunohistochemical results. The level of Sp1 in EGF and FGF-2 treated cells was respectively, 2.9- and 2.6-fold higher compared to that in controls. Conclusions: The present study shows that the Sp1 expression in corneal fibroblasts is subjected to regulation by cytokines, especially EGF and FGF-2. This may have implications in situations with altered cytokine expression such as in wound healing or in diseases including keratoconus.
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