Endothelin-1 decreases endothelial NOS expression and activity through ETA receptor-mediated generation of hydrogen peroxide

Stephen Wedgwood, Stephen M. Black

Research output: Contribution to journalArticlepeer-review

129 Scopus citations


Similar to infants born with persistent pulmonary hypertension of the newborn (PPHN), there is an increase in circulating ehdothelin-1 (ET-1) and decreased endothelial nitric oxide synthase (eNOS) gene expression in an ovine model of PPHN. These abnormalities lead to vasoconstriction and vascular remodeling. Our previous studies have demonstrated that reactive oxygen species (ROS) levels are elevated in the pulmonary arteries from PPHN lambs and that ET-1 increases ROS production in pulmonary arterial smooth muscle cells (PASMC) in culture. Thus the objective of this study was to determine whether there was a feedback mechanism between the ET-1-mediated increase in ROS in fetal PASMC (FPASMC) and a decrease in eNOS gene expression in fetal pulmonary arterial endothelial cells (FPAEC). Our results indicate that ET-1 increased H 2O2 levels in FPASMC in an endothelin A receptor-dependent fashion. This was observed in both FPASMC monoculture and in cocultures of FPASMC and FPAEC. Conversely, ET-1 decreased H2O2 levels in FPAEC monoculture in an endothelin B receptor-dependent fashion. Furthermore, ET-1 decreased eNOS promoter activity by 40% in FPAEC in coculture with FPASMC. Promoter activity was restored in the presence of catalase. In FPAEC in monoculture treated with 0-100 μM H2O2, 12 μM had no effect on eNOS promoter activity, but it increased eNOS protein levels by 50%. However, at 100 μM, H2O2 decreased eNOS promoter activity and protein levels in FPAEC by 79 and 40%, respectively. These data suggest a role for smooth muscle cell-derived H2O2 in ET-1-mediated downregulation of eNOS expression in children born with PPHN.

Original languageEnglish (US)
Pages (from-to)L480-L487
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number3 32-3
StatePublished - Mar 2005


  • Cell signaling
  • Endothelial nitric oxide synthase
  • Endothelin A
  • Gene expression
  • Nitric oxide synthase
  • Pulmonary hypertension
  • Reactive oxygen species

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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