Early Phase of UVB-induced GM-CSF Upregulation in Epithelial Cell Line is not Totally Dependent on IL-1α

ABSTRACT

BACKGROUND: It was demonstrated that ultraviolet(UV) B light induces the release of IL-1α in cultured human epithelial cell line and augmentation of GM-CSF production by UVB is reported to be mediated by IL-1α in the murine keratinocyte cell line Pam 212. OBJECTIVE: The purpose of this study was to evaluate the effects of UVB on kinetic profile of IL-1 and GM-CSF mRNA expression and to see whether synthesis of GM-CSF by UVB can be completely inhibited by blocking IL-1α mediated pathway. METHODS: We used a competitive RT-PCR for measuring cytokine gene expression in epithelial cell line after UV radiation. RESULTS: The IL-1α mRNA increased as early as 1h after UV irradiation, and then decreased at 3h after the irradiation. Thereafter, the response of IL-1α mRNA was upregulated with a second peak at 6h after the UV irradiation. However, mRNA for GM-CSF increased at 1h after UV light exposure and anti-IL-1α antibodies could only partially inhibit UV-augmented GM- CSF production. CONCLUSION: UVB induced GM-CSF production seemed to be mainly mediated by UVB induced IL-1α but these results suggest that UVB may also induce GM-CSF production through an IL-1α independent pathway.