The interleukin-1 type 2 receptor gene displays immediate early gene responsiveness in glucocorticoid-stimulated human epidermal keratinocytes

Human epidermal keratinocytes (HEKs) in primary culture (P2-P4) were used t o study glucocorticoid (GC)mediated transcription of the genes encoding the constitutively expressed interleukin-1 type 1 receptor (IL-1R1) and the in ducible interleukin-1 type 2 receptor (IL-1R2). Utilizing Northern dot blot analysis and a quantitative reverse transcription-polymerase chain reactio n protocol for IL-1R1 and IL-1R2, dexamethasone and, in particular, the bud esonide epimer R were shown to effectively and rapidly induce transcription from the IL-IR2 gene when compared with IL-1R1 or beta-actin RNA message l evels in the same sample. Southern blot analysis of newly generated IL-1R2 reverse transcription-polymerase chain reaction products using end-labeled IL-1R2 intron probes suggested that GC enhancement of IL-1R2 expression was regulated primarily at the level of de novo transcription. GC-induced IL-1 R2 gene transcription displayed features characteristic of a classical imme diate early gene response, including a signal transduction function, a rela tively low basal abundance, a rapid, transient induction, cycloheximide sup erinduction, actinomycin D suppression, and a rapid decay of IL-1R2 RNA mes sage. Parallel time course kinetic analysis of IL-1R2 RNA message levels wi th Western immunoblotting revealed tight coupling of de novo IL-IR2 gene tr anscription with translation of the IL-1R2 RNA message; a newly synthesized (similar to 46-kDa) IL-1RS protein was detected in the HEK growth medium a s early as 1 h after budesonide epimer R treatment. These data indicate tha t different GC compounds can variably up-regulate the IL-1R2 response in HE Ks through transcription-mediated mechanisms and, for the first time, sugge st that a gene encoding a soluble cytokine receptor can respond like an imm ediate early gene.