Endothelin-1 enhances β2-adrenoceptor gene transcription in human lung fibroblasts

AimsThe present study aimed to explore possible effects of endothelin-1 (ET-1) on ß2-adrenoceptor gene transcription in human lung fibroblasts.Main methodsMRC-5 human lung fibroblasts were cultured in absence or presence of test substances, followed by ß2-adrenoceptor mRNA determination by quantitative real time PCR.Key findingsET-1 caused a marked and rapid in onset (1 hr) increase in β2-adrenoceptor mRNA, an effect additive to that of short time (1 hr) exposure to the β2-adrenoceptor agonist olodaterol. The stimulatory effect of ET-1 on β2-adrenoceptor mRNA was prevented by the non-selective ET-A/ET-B receptor antagonist bosentan, indicating that it was mediated via specific ET receptors. In the presence of actinomycin D the effect of ET-1 was prevented indicating that ET-1 acts via increased transcription of the β2-adrenoceptor gene. ET-1-induced up-regulation of β2-adrenoceptor mRNA was also seen in the presence of cycloheximide excluding indirect effects via up-regulation of other regulatory proteins.ConclusionsET-1 can up-regulate β-adrenoceptor gene transcription in human lung fibroblasts.