UV-A irradiation induces transcription of IL-6 and TNF alpha genes in human keratinocytes and dermal fibroblasts.
OBJECTIVE
To determine whether UV-A irradiation induces synthesis of inflammatory cytokines in the skin.


METHODS
Human keratinocytes and dermal fibroblasts were cultured and exposed to various doses of UV-A radiation. The cellular distribution of IL-6 and TNF alpha was determined by indirect immunofluorescence and by flow cytometry with monoclonal anti-IL-6 and anti-TNF alpha antibodies. Cytokine production was measured in the supernatants using an ELISA. IL-6 and TNF alpha transcription induced by UV-A was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) amplification.


RESULTS
IL-6 and TNF alpha were detected in small amounts in nonUV-A-irradiated cell. UV-A exposure was followed by significant increases in IL-6 and TNF alpha expression and by small increases in IL-6 and TNF alpha levels in culture supernatants. RT-PCR demonstrated a UV-A-mediated increase in the transcription of IL-6 and TNF alpha genes.


CONCLUSIONS
Synthesis of IL-6 and TNF alpha can be induced by UV-A irradiation. This effect of UV-A may contribute to the inflammatory skin changes seen during lupus flare-ups after sun exposure.
Immunotechnology Unit, CBE, Universidad Autónoma de Zacatecas, Guadalupe, Mexico. avalose@cantera.reduaz.mx
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Avalos-Díaz
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Alvarado-Flores
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Herrera-Esparza
D015153:Blotting, Western; D002457:Cell Extracts / Q000737:chemistry; D048429:Cell Size / Q000528:radiation effects; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000528:radiation effects; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000528:radiation effects; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics; D014466:Ultraviolet Rays
D002457:Cell Extracts; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha