Interleukin-1α, epidermal growth factor, and transforming growth factor-β exhibit differential kinetics on endothelin-1 synthesis in amnion cells

OBJECTIVE: To investigate the effects of three cytokines, interleukin- 1α (IL-1α), epidermal growth factor (EGF), and transforming growth factor- β (TGF-β), on the regulation of endothelin-1 (ET-1) mRNA and protein production in human amnion cells. METHODS: Human amnion cells were harvested from uncomplicated pregnancies undergoing elective cesarean delivery at term and grown in primary monolayer culture. Cells were treated with IL-1α, EGF, and TGF-β for dose-response and time course experiments. Northern analysis was used to determine ET-1 mRNA expression, and enzyme-linked immunosorbent assay was used for ET-1 peptide determination. RESULTS: Interleukin-1α, EGF, and TGF-β induced the expression of ET-1 mRNA and protein in a dose- and time-dependent fashion. The kinetics of ET-1 mRNA production did not differ markedly with respect to the inducing cytokine, but the kinetics of ET-1 protein production was quite different. Interleukin-1α and EGF stimulated a rapid increase in ET-1 that peaked by 24 hours, and the levels declined to just above the detection limit by 72 hours. In contrast, TGF-β-stimulated cells showed modest ET-1 production at early times (4-24 hours) and then gradually increased and peaked at 72 hours. CONCLUSIONS: Cytokines modulate the expression of ET-1 mRNA and its cognate protein in human amnion cells. The differential kinetics of ET-1 peptide expression in amnion cells suggests that ET metabolism as well as synthesis contribute to the net expression of endothelin in amnion.