Effect of double-stranded RNA on the expression of epithelial neutrophil activating peptide-78/CXCL-5 in human endothelial cells.

Epithelial neutophil activating peptide-78 (ENA-78)/CXCL-5 is a member of CXC chemokines. ENA-78 was originally described as a factor produced by epithelial cells only. But other types of cells including vascular endothelial cells also produce it. ENA-78 production by endothelial cells may be important for the regulation of neutrophil activation in inflammatory reactions. Polyinosinic-polycytidylic acid (poly IC) is a synthetic double-stranded RNA, which mimics the viral infection when applied to cells and affects the expression of various genes related to inflammatory reactions. In the present study, we examined the effect of poly IC on the expression of ENA-78 in human umbilical vein endothelial cells (HUVEC). HUVEC in culture were treated with poly IC and the expression of ENA-78 mRNA and protein were analyzed by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Poly IC induced ENA-78 expression in time- and concentration-dependent manners. Th2-type cytokine IL-4 partially inhibited the induction of ENA-78 by poly IC. 2-Aminopurine, an inhibitor of dsRNA-dependent kinase, suppressed the induction of ENA-78 by poly IC. ENA-78 may be involved in the inflammatory reactions elicited by viral infection in endothelial cells.