Signal transduction pathways involved in lipopolysaccharide-induced production of PGE(2) by human microvascular endothelial cells

Lipopolysaccharide induces the expression of prostaglandin H synthase-2 wit h subsequent production of PGE(2) in human microvascular endothelial cells. In order to investigate the signaling pathways that are involved in the LP S-induced production of PGE(2), the roles of several second messenger syste ms in this process were evaluated. Treatment of human microvascular endothe lial cells with the tyrosine kinase inhibitors herbimycin A and genistein s ignificantly inhibited LPS-mediated PGE(2) production. Western blotting dem onstrated that LPS induced the phosphorylation of p42, p44 and p38 MAP kina ses. Both PD98059, an inhibitor of p42 and p44 MAP kinase activation, and S B203580, an inhibitor of p38 MAP kinase, blocked LPS-induced PGE(2) product ion. Inhibition of PKC activity by staurosporine and GF109203X resulted in a potentiation of the LPS response. Treatment of the cells with SN50, an NF -kappa B inhibitor, resulted in inhibition of the LPS-mediated PGE(2) produ ction. These results suggest that LPS induces PGE(2) production in human mi crovascular endothelial cells through sequential activation of tyrosine kin ases, ERK and p38 MAP kinases and NF-kappa B. In addition, PKC activity exe rts a feedback control of PGE(2) production in LPS-stimulated microvessel-d erived endothelial cells.