Type I and Type II Interferons Upregulate Functional Type I Interleukin-1 Receptor in a Human Fibroblast Cell Line TIG-1

The regulation of type I interleukin-1 receptor (IL-1R) expression by type I, interferon (IFN)-α A/D, and type II IFN, IFN-α, in a human fibroblast cell line TIG-1 was investigated. After 2 h stimulation with human IFN-α A/D or IFN-γ, the levels of type I IL-1R mRNA increased. We previously reported that IL-1 upregulates transcription and cell surface molecules of type I IL-1R in TIG-1 cells through induction of prostaglandin (PG) E2 and cAMP accumulation. However, indomethacin was unable to inhibit the effect of IFNs, indicating that IFNs augment IL-1R expression through a pathway distinct from that of IL-1. The augmentation was also observed in other fibroblast cell lines. Nuclear run-on assays and studies of the stability of mRNA suggested that the increase in IL-1R mRNA was a result of the enhanced transcription of IL-1R gene. Binding studies using 125I-IL-1α revealed that the number of cell surface IL-1R increased with no change in binding affinity by treatment with these IFNs. Pretreatment of the ce...