FIGURE 1.

A, the effect of TNFα and IFNγ on ET-1 expression in HPASM cells. HPASM cells were cultured for 24 h in the presence of TNFα, IFNγ, IL-1β (all at 10 ng/ml), or lipopolysaccharide (LPS, 1 μg/ml). ET-1 released into the supernatant was measured by ELISA. Results are presented as the means ± S.E. from five separate experiments performed in cells from three separate patients. *, p < 0.05 versus control by one way ANOVA. B and C, HPASM cells were cultured in the absence or presence of the endothelin converting enzyme inhibitor phosphoramidon (phos, 50 μm) for 30 min before treatment with medium (con) or TNFα and IFNγ (both at 10 ng/ml). After a further 24-h incubation, supernatants were collected for determination of ET-1 and Big ET-1 (B and C, respectively) by ELISA. Results are presented as the mean from one representative patient repeated in triplicate. D and E, synergistic increase of ET-1 release from HPASM cells treated with 10 ng/ml TNFα and increasing concentrations of IFNγ (D) or 10 ng/ml IFNγ and increasing concentrations of TNFα (E). Results are expressed as the mean from a single representative experiment repeated in triplicate. F, the synergistic effect of TNFα and IFNγ in stimulating expression of preproET-1 mRNA from HPASM cells after 18 h. Results are expressed as the ratio of preproET-1 message to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) message and are expressed as the mean ± S.E. of three independent patient cells. *, p < 0.01 compared with control by one way ANOVA.