IL–1β-stimulated activation of ERK1/2 and p38α MAPK mediates the transcriptional up-regulation of IL–6, IL–8 and GRO-α in HeLa cells

Epithelial cells represent the first line of defense against infection. Here we have studied the production of inflammatory mediators induced by IL–1β in the HeLa epithelial cell line. We found that GRO-α, IL–6 and IL–8 were the only three inflammatory mediators elevated out of 36 tested. Specific inhibition of p38α MAP kinase or preventing the activation of ERK1/ERK2 partially reduced the production of these substances, while the combined blockade of both pathways almost abolished secretion. The suppression of these signaling pathways mainly reduced transcription of the genes encoding GRO-α, IL–6 and IL–8, rather than affecting mRNA stability, translation or secretion. The production of these three inflammatory mediators was shown to account for the ability of the HeLa cell culture medium to stimulate the migration of monocytes/macrophages, suggesting a key role for p38 MAPK and ERK1/ERK2 in orchestrating the epithelial cell response to infection.