Cooperative interaction of nuclear factor-kappa B- and cis-regulatory enhancer binding protein-like factor binding elements in activating the interleukin-8 gene by pro-inflammatory cytokines.

TLDR

IL‑8 is a cytokine that recruits neutrophils and T cells, and its transcription is induced only by IL‑1 and TNF, with the promoter region containing two cis‑elements for NF‑κB‑like and CREB‑like factors. Reporter assays in human fibrosarcoma cells revealed that the −94 to −71 bp region of the IL‑8 promoter is essential and sufficient for induction by IL‑1, TNF, or PMA. Mutating either cis‑element abolishes responsiveness, demonstrating that cooperative binding of NF‑κB‑like and CREB‑like factors is required for IL‑1 or TNF‑mediated IL‑8 induction.

Abstract

A novel cytokine, interleukin-8 (IL-8), may play major roles in the inflammatory process by recruiting neutrophils and T cells into inflammatory sites. The production of this cytokine is not constitutive and is induced in a variety of cell types by stimulation with mitogens and cytokines. Among cytokines, only IL-1 and tumor necrosis factor (TNF) can induce IL-8 gene expression at the transcriptional level. Transfection of a human fibrosarcoma cell line with chloramphenicol acetyltransferase expression plasmids linked to a 5'-flanking deletion mutants of the IL-8 gene demonstrated that the nucleotides between -94 and -71 base pairs from the start of the first exon are essential and sufficient for the IL-8 induction by either IL-1, TNF, or phorbol 12-myristate 13-acetate. This sequence is composed of two cis-elements; one is the potential binding site for a nuclear factor-kappa B-like factor and the other for a cis-regulatory enhancer binding protein-like factor. Mutations in either elements abolished IL-1, TNF, and phorbol 12-myristate 13-acetate responsiveness. This report provides the first evidence that cooperation between two distinct cis-elements may be required for induction of gene expression by either IL-1 or TNF.