Critical role of NADPH oxidase-derived reactive oxygen species in generating Ca2+ oscillations in human aortic endothelial cells stimulated by histamine

Qinghua Hu, Zu Xi Yu, Victor J. Ferrans, Kazuyo Takeda, Kaikobad Irani, Roy C. Ziegelstein

Research output: Contribution to journalArticle

Abstract

There is increasing evidence that intracellular reactive oxygen species (ROS) play a role in cell signaling and that the NADPH oxidase is a major source of ROS in endothelial cells. At low concentrations, agonist stimulation of membrane receptors generates intracellular ROS and repetitive oscillations of intracellular Ca2+ concentration ([Ca2+]i) in human endothelial cells. The present study was performed to examine whether ROS are important in the generation or maintenance of [Ca2+]i oscillations in human aortic endothelial cells (HAEC) stimulated by histamine. Histamine (1 μM) increased the fluorescence of 2′,7′-dihydrodichlorofluorescin diacetate in HAEC, an indicator of ROS production. This was partially inhibited by the NADPH oxidase inhibitor diphenyleneiodonium (DPI, 10 μM), by the farnesyltransferase inhibitor H-Ampamb-Phe-Met-OH (2 μM), and in HAEC transiently expressing Rac1N17, a dominant negative allele of the protein Rac1, which is essential for NADPH oxidase activity. In indo 1-loaded HAEC, 1 μM histamine triggered [Ca2+]i oscillations that were blocked by DPI or H-Ampamb-Phe-Met-OH. Histamine-stimulated [Ca2+]i oscillations were not observed in HAEC lacking functional Rac1 protein but were observed when transfected cells were simultaneously exposed to a low concentration of hydrogen peroxide (10 μM), which by itself did not alter either [Ca2+]i or levels of inositol 1,4,5-trisphosphate (Ins-1,4,5-P3). Thus, histamine generates ROS in HAEC at least partially via NADPH oxidase activation. NADPH oxidase-derived ROS are critical to the generation of [Ca2+]i oscillations in HAEC during histamine stimulation, perhaps by increasing the sensitivity of the endoplasmic reticulum to Ins-1,4,5-P3.

Original languageEnglish (US)
Pages (from-to)32546-32551
Number of pages6
JournalJournal of Biological Chemistry
Volume277
Issue number36
DOIs
StatePublished - Sep 6 2002

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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