title: S100A8 induction in keratinocytes by ultraviolet A irradiation is dependent on reactive oxygen intermediates.
abstract: Cutaneous exposure to ultraviolet (UV) A (320-400 nm) results in the formation of damaging reactive oxygen intermediates, which are implicated as mediators of DNA damage, apoptosis, and photoaging. S100A8 is a low-molecular-weight calcium-binding protein, highly sensitive to oxidation. In this study, UVA-induced S100A8 expression by keratinocytes was investigated. UVA (50-100 kJ per m2) strongly induced S100A8 in differentiated keratinocytes in the epidermis of BALB/c mice. Similarly, S100A8 mRNA and monomeric protein were significantly upregulated in PAM212 cells (a murine keratinocyte cell line) in response to 10 kJ per m2 UVA 24 h after irradiation. Although S100A9 associates with S100A8 in neutrophils and abnormally differentiated keratinocytes (human psoriasis), in this study it was not coinduced with keratinocyte S100A8. Dorsal application of 4-hydroxy-tempo (a superoxide dismutase-mimicking agent) to mice concentration-dependently reduced UVA-induced S100A8 expression. Incubation of PAM212 cells with superoxide dismutase and catalase during UVA irradiation also abrogated S100A8 induction. These results suggest that UVA-induced S100A8 is expressed by keratinocytes in response to generation of reactive oxygen intermediates.
authors.affiliation: Department of Microbiology and Infectious Diseases, School of Medicine and Flinders Medical Research Institute, Flinders University, Adelaide, Australia.
authors.forename: Michele A
authors.initials: MA
authors.lastname: Grimbaldeston
authors.forename: Carolyn L
authors.initials: CL
authors.lastname: Geczy
authors.forename: Nicodemus
authors.initials: N
authors.lastname: Tedla
authors.forename: John J
authors.initials: JJ
authors.lastname: Finlay-Jones
authors.forename: Prue H
authors.initials: PH
authors.lastname: Hart
mesh_terms: D000818:Animals; D040501:Calgranulin A / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation / Q000528:radiation effects*; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D010084:Oxidation-Reduction; D012333:RNA, Messenger / Q000032:analysis; D017382:Reactive Oxygen Species; D014466:Ultraviolet Rays
chemical_list: D040501:Calgranulin A; D012333:RNA, Messenger; D017382:Reactive Oxygen Species