The Production IL-21 and VEGF in UVB-irradiated Human Keratinocyte Cell Line, HaCaT.
BACKGROUND
Ultraviolet B (UVB) induces multiple inflammatory and carcinogenic reactions. In skin, UVB induces to secrete several kinds of inflammatory cytokines from keratinocytes and also increases angiogenic process via the modulation of vascular endothelial growth factor (VEGF) production. Interleukin-21 (IL-21) is an inflammatory cytokine and produced by activated T cells. The biologic functions of IL-21 have not yet extensively studied.


METHODS
In the present study, we investigate the production of IL-21 from human keratinocyte cell line, HaCaT and its biological effect after exposure to UVB.


RESULTS
First, we confirmed the IL-21 production and its receptor expression in HaCaT. And then, the change of IL-21 and VEGF production in HaCaT by UVB irradiation was examined. Not only IL-21 but also VEGF production was enhanced by UVB irradiation. Next, to determine relationship of enhanced production of IL-21 and VEGF, we detected VEGF production after neutralization of IL-21. VEGF production was reduced by IL-21 neutralization, which indicates that the IL-21 is involved in the VEGF production.


CONCLUSIONS
Taken together, our results suggest that IL-21 and VEGF production is enhanced by UVB irradiation in HaCaT. In addition, it seems that IL-21 plays a role in the angiogenic process in skin via the modulation of VEGF production.
Department of Anatomy and Tumor Immunity Medical Research Center, Seoul National University College of Medicine, Seoul 110-799, Korea.
Hyemin
H
Kim
Jae Seung
JS
Kang
Wang Jae
WJ
Lee