p38 mitogen-activated protein kinase regulates IL-8 expression in human pulmonary vascular endothelial cells

The aim of this study was to examine the role of p38 mitogen-activated prot ein (MAP) kinase in interleukin (IL)-8 expression in tumour necrosis factor (TNF)-alpha- and IL-1 alpha-stimulated human pulmonary vascular endothelia l cells. To this end, the phosphorylation and activation of p38 MAP kinase and the e ffect of SE 203580, a specific inhibitor of p38 MAP kinase activity, on p38 MAP kinase activity and IL-8 expression in TNF-alpha- and IL-1 alpha-stimu lated human pulmonary vascular endothelial cells were examined. TNF-alpha- and IL-1 alpha- induced phosphorylation and activation of p38 MA P kinase and IL-8 expression in human pulmonary endothelial cells. Inhibiti on of TNF-alpha- and IL-1 alpha-induced p38 MAP kinase activity by SE 20358 0 inhibited TNF-alpha- and IL-1 alpha-induced IL-8 protein production as we ll as IL-8 messenger ribonucleic acid (mRNA) expression, indicating that SE 203580 was effective at the transcriptional level. These results indicate that p38 mitogen-activated protein kinase plays an i mportant role in the tumour necrosis factor-alpha- and interleukin-1 or-act ivated signalling pathway which regulates interleukin-8 expression in human pulmonary vascular endothelial cells.