[Molecular mechanism of interleukin-8 gene expression]

Evidence is accumulating that interleukin-8 (IL-8), discovered as a potent neutrophil chemotactic factor, plays a crucial role in establishing acute neutrophil-mediated inflammation by exerting various activities against non-leukocytic as well as leukocytic cells. Various types of cells can rapidly produce a large amount of IL-8 upon stimulation with inflammatory stimuli, such as lipopolysaccharide, IL-1, and tumor necrosis factor (TNF). However, IL-8 production is tightly regulated at several levels, particularly at the transcriptional levels to prevent aberrant production. Our previous experiments demonstrated that IL-8 gene transcription requires the cooperative activation of a transcription factor, NF-kappa B, with an additional transcription factor, AP-1 or NF-IL6, depending on types of cells and stimuli. In addition, we recently observed that infection with Helicobacter pylori or cytomegalovirus activated NF-kappa B, therapy inducing IL-8 protein secretion as well as IL-8 gene transcription. Moreover, IL-8, in turn, enhanced cytomegalovirus replication and infectious virion production. Collectively, these results suggest the potential involvement of IL-8 in the pathology of bacterial or viral infection.