Interleukin-1β and dexamethasone regulate gene expression of prostaglandin H synthase-2 via the NF-κB pathway in human amnion derived WISH cells

Interleukin-1 beta (IL-1 beta) stimulated PGE, synthesis in human amnion derived WISH cells, whereas dexamethasone blocked IL-1 beta-mediated stimulation of PGE, production. Sequence analysis of the 5'-flanking region of the human prostaglandin H synthase-2 (PGHS-2) gene indicates two putative NF-kB binding sites. Mutation of a single site or both sites resulted in significantly decreased activity of the PGHS-2 promoter. IL-1 beta treatment increased significantly the native promoter activity and this increase was attenuated by using the NF-kB-mutant promoter. Dexamethasone treatment also decreased the IL-1 beta mediated stimulation of the PGHS-2 native promoter but not the NF-kB mutant promoter. Furthermore, the involvement of the NF-kB was supported by electrophoretic mobility shift assay which revealed an increased nuclear binding of the NF-kB probe upon IL-1 beta induction and a decreased nuclear binding of the NF-kB probe upon dexamethasone pre-treatment. These results provide convincing evidence that NF-kB may mediate the IL-1 beta stimulation of PGHS-2 gene expression as well as the dexamethasone inhibition of the IL-1 beta induction process in WISH cells.