ISSN:
1600-0625
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract 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 Ca2+ 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/m2 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/m2. After 300 J/m2 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/m2 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1600-0625.1994.tb00263.x
