UVB-induced GM-CSF production is suppressed by dexamethasone in HaCaT cells.

Abstract

Epidermal keratinocytes are important sources of a wide variety of cytokines that include the Granulocyte-macrophage Colony Stimulating Factor (GM-CSF). Glucocorticoids have been shown to inhibit the production of several cytokines. However, their effect on GM-CSF synthesis by keratinocytes is still unknown. The effects of glucocorticoid on GM-CSF production by keratinocytes were evaluated using ELISA and RT-PCR analysis. GM-CSF secretion by HaCaT cells increased with increasing UVB exposure. Dexamethasone suppressed basal release of GM-CSE In addition, it strongly inhibited both the UVB-mediated augmentation of GM-CSF protein production and mRNA expression. Lincomycin enhanced slightly the inhibitory effect of dexamethasone on GM-CSF synthesis, while lincomycin itself had no effect on GM-CSF secretion. Results showed that dexamethasone suppressed basal release and UVB-induced production of GM-CSF by keratinocytes.