Cigarette smoke extract induces endothelin-1 via protein kinase C in pulmonary artery endothelial cells

We examined the mechanism of endothelin (ET)-1 regulation by cigarette smok e extract (CSE) and the effect of platelets on CSE-induced stimulation of E T-1 gene expression in human and bovine pulmonary artery endothelial cells (PAECs). Our data show that CSE (1%) induces ET-1 gene expression (after 1 h) and ET-1 peptide synthesis (after 4 h) in bovine PAECs. The induction of preproET-1 mRNA level was due to de novo transcription, and new protein sy nthesis was not required for this induction. The protein kinase C inhibitor s staurosporine (10(-8) mol/l) and calphostin C (10(-7) mol/l) abolished th e induction of ET-1 gene expression by CSE in bovine and human PAECs. Altho ugh a lower concentration of platelets (10(6) cells/ml in bovine PAECs; 10( 7) cells/ml in human PAECs) did not significantly alter ET-1 gene expressio n in PAECs, incubation of platelets with CSE (1%) and PAECs produced a sign ificant increase in preproET-1 mRNA and ET-1 peptide compared with the valu es in the presence of CSE (1%) alone. CSE (1%) induced platelet aggregation and increased the expression of platelet membrane glycoproteins ex vivo. T hus our data suggest that CSE stimulates ET-1 gene expression via PKC in PA ECs. CSE and platelets showed a synergistic effect on ET-1 gene expression, possibly through the activation of platelets by CSE.