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Differential modulation of interleukin‐1α (IL‐1α) and interleukin‐1β(IL‐1β in human epidermal keratinocytes by UVB
Author(s) -
Kondo Seiji,
Sauder Daniel N.,
Kono Takeshi,
Galley Kevin A.,
McKenzie Roderick C.
Publication year - 1994
Publication title -
experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 96
eISSN - 1600-0625
pISSN - 0906-6705
DOI - 10.1111/j.1600-0625.1994.tb00263.x
Subject(s) - interleukin , messenger rna , microbiology and biotechnology , interleukin 1β , interleukin 4 , interleukin 9 , chemistry , cytokine , biology , immunology , biochemistry , gene
Conflicting reports exist concerning ultraviolet‐B (UVB) effects on keralinocyte (KC) interleukin‐l (IL‐1) expression. To clarify the modulatery effects of UVB on IL‐1, the following study was undertaken. Normal human epidermal KCs cultured in a standard low Ca 2+ and serum‐free medium were irradiated in quiescent phase with UVB. In this study, we used semiquantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) to determine the mRNA level of interleukin‐1α (IL‐1α) and interleukin‐1β (IL‐β). After exposure to 100 or 300 J/m 2 UVB, a transient increase in mRNA levels was observed within I hour for IL‐1α and 3 to 6 h for IL‐β Following this transient induction, mRNA levels for both IL‐1α and IL‐1β returned to steady‐state levels after 100 J/m 2 . After 300 J/m 2 irradiation, IL‐1α and IL‐1β levels were downregulated compared to unirradiated cultures at 24‐h post‐irradiation. The half‐life for IL‐1α and IL‐1β was estimated using actinomycin D treatment. Both IL‐1α and IL‐1β mRNAs half‐lives (t1/2) decreased faster in irradiated cells (t1/2 = 30 minutes for IL‐1α and 2 h for IL‐1β) compared to unirradiated cells (t1/2= 1 h and 4 h, respectively). These results suggest that IL‐1α and IL‐1β mRNA expression are differentially regulated by UVB. In contrast to down‐regulation of mRNA levels, a significant increase in IL‐1α protein levels, measured by ELISA. was observed in culture supernatant from 6 h to 24 h after 300 J/m 2 UVB irradiation. Cycloheximide treatment did not abrogate this increase in IL‐1α protein level. Since this dose of UVB irradiation decreased the stability of IL‐1α and IL‐1β mRNA, this suggests that the release of IL‐1α after UVB irradiation was due to leakage from UVB‐damaged cells and not from de novo protein synthesis.