20-HETE increases superoxide production and activates NAPDH oxidase in pulmonary artery endothelial cells

Meetha Medhora, Yuenmu Chen, Stephanie Gruenloh, Daniel Harland, Sreedhar Bodiga, Jacek Zielonka, Debebe Gebremedhin, Ying Gao, J R Falck, Siddam Anjaiah, Elizabeth R. Jacobs

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Reactive oxygen species (ROS) signal vital physiological processes including cell growth, angiogenesis, contraction, and relaxation of vascular smooth muscle. Because cytochrome P-450 family 4 (CYP4)/20- hydroxyeicosatetraenoic acid (20-HETE) has been reported to enhance angiogenesis, pulmonary vascular tone, and endothelial nitric oxide synthase function, we explored the potential of this system to stimulate bovine pulmonary artery endothelial cell (BPAEC) ROS production. Our data are the first to demonstrate that 20-HETE increases ROS in BPAECs in a time- and concentration-dependent manner as detected by enhanced fluorescence of oxidation products of dihydroethidium (DHE) and dichlorofluorescein diacetate. An analog of 20-HETE elicits no increase in ROS and blocks 20-HETE-evoked increments in DHE fluorescence, supporting its function as an antagonist. Endothelial cells derived from bovine aortas exhibit enhanced ROS production to 20-HETE quantitatively similar to that of BPAECs. 20-HETE-induced ROS production in BPAECs is blunted by pretreatment with polyethylene-glycolated SOD, apocynin, inhibition of Rac1, and a peptide-based inhibitor of NADPH oxidase subunit p47phox association with gp91. These data support 20-HETE-stimulated, NADPH oxidase-derived, and Rac1/2-dependent ROS production in BPAECs. 20-HETE promotes translocation of p47phox and tyrosine phosphorylation of p47phox in a time-dependent manner as well as increased activated Rac1/2, providing at least three mechanisms through which 20-HETE activates NADPH oxidase. These observations suggest that 20-HETE stimulates ROS production in BPAECs at least in part through activation of NADPH oxidase within minutes of application of the lipid.

Original languageEnglish (US)
Pages (from-to)L902-L911
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume294
Issue number5
DOIs
StatePublished - May 2008

Keywords

  • CYP4A
  • Hydrogen peroxide
  • Rac1/2
  • Reactive oxygen species
  • Superoxide

ASJC Scopus subject areas

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

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