Studies on the regulatory mechanisms of interleukin-8 gene expression in resting and IFN-gamma-treated neutrophils: evidence on the capability of staurosporine of inducing the production of interleukin-8 by human neutrophils.

To understand how expression of IL-8 mRNA is regulated, we studied the effects of Staurosporine, H7, phorbol-myristate-acetate and Dexamethasone in human neutrophils subsequently treated with IFN-gamma. Our results can be summarized as follows: a) IL-8 mRNA steady state levels were enhanced in a dose dependent fashion by both Staurosporine and phorbol-myristate-acetate, were not influenced by H7, but were decreased by Dexamethasone; b) the negative effect of IFN-gamma on IL-8 mRNA accumulation was prevented by Staurosporine and phorbol-myristate-acetate, was not influenced by H7, and was potentiated by Dexamethasone; c) IL-8 mRNA induction caused by Staurosporine was accompanied by a time and dose dependent release of IL-8 into the PMN supernatants.