GM-CSF production by epithelial cell line: upregulation by ultraviolet A

It was demonstrated that UVB increases synthesis and expression of IL-l alpha and GM-CSF by keratinocytes. Upregulation of GM-CSF by WE is reported to be mediated by IL-l alpha. However, regulation of IL-l alpha and GMCSF by WA is not well-known. The purpose of the present study was to evaluate the effects of UVA on IL-l alpha and GM-CSF production. Here we used a competitive RT-PCR for measuring cytokine gene expression in an epidermal cell line after UVA irradiation. IL-l alpha and GM-CSF mRNA did not show any change at 1 h and 6 h following exposure to UVA. After WA irradiation, however, IL-l alpha mRNA decreased and GM-CSF mRNA increased at 24 h and the level of GM-CSF in culture supernatant increased at 24 h and 48 h. Addition of antihuman IL-l alpha neutralizing antibody to WA irradiated cells did not prevent the increase of GM-CSF mRNA expression. These results suggest that UVA radiation may induce GMCSF production through an IL-l alpha independent pathway.