title: Ultraviolet B irradiation-enhanced interleukin (IL)-6 production and mRNA expression are mediated by IL-1 alpha in cultured human keratinocytes.
abstract: Ultraviolet (UV) B radiation may trigger cutaneous inflammatory responses by directly inducing epidermal keratinocytes to elaborate specific cytokines such as interleukin (IL-1) and IL-6. Because IL-1 is a potent inducer of IL-6, one may speculate that the release of IL-6 by keratinocytes after UV exposure is mediated via the release of IL-1 in an autocrine or paracrine manner. We demonstrated that UVB irradiation upregulated IL-1 alpha mRNA at a lower dose (15 mJ/cm2) and then downregulated IL-1 alpha mRNA expression at high doses (30-40 mJ/cm2). The kinetic profile of IL-1alpha mRNA expression showed a biphasic response, with the early increase by 1 h after UV exposure and the secondary increase at 6 h after UV. On the other hand, the expression of IL-6 mRNA was increased with increasing doses of UVB (0-45 m/J/cm2) and showed a single peak at 6 h post UV. These results may indicate that UVB radiation could regulate the expression of IL-1alpha and IL-6 mRNA in keratinocytes by different mechanisms. Our data show that anti-human IL-1alpha antibody inhibits UV-induced IL-6 production and mRNA expression in cultured keratinocytes. The addition of recombinant IL-1alpha to the medium increased IL-6 synthesis and augmented IL-6 production and mRNA expression in cultured human keratinocytes by UVB irradiation. These results support the hypothesis that UVB irradiation-enhanced IL-6 production and mRNA expression may be mediated by IL-1alpha.
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine, Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Chung
authors.forename: S H
authors.initials: SH
authors.lastname: Youn
authors.forename: W S
authors.initials: WS
authors.lastname: Koh
authors.forename: H C
authors.initials: HC
authors.lastname: Eun
authors.forename: K H
authors.initials: KH
authors.lastname: Cho
authors.forename: K C
authors.initials: KC
authors.lastname: Park
authors.forename: J I
authors.initials: JI
authors.lastname: Youn
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000528:radiation effects; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics / Q000502:physiology*; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis*; D011817:Rabbits; D014466:Ultraviolet Rays
chemical_list: D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger