Synthesis of 8-epi-prostaglandin F(2α) by human endothelial cells: Role of prostaglandin H2 synthase

Michael T. Watkins, George M. Patton, Hiram M. Soler, Hassan Albadawi, Donald E. Humphries, James E. Evans, Hiroko Kadowaki

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

The experiments described in this paper were designed to determine the mechanism underlying the increase in 8-isoprostaglandin F(2α) (8-epi-PGF(2α)) production by cultured human endothelial cells during reoxygenation following hypoxia. Human umbilical artery endothelial cells were grown on microcarrier beads and exposed to sequential periods of normoxia, hypoxia, and reoxygenation. The amount of 8-epi-PGF(2α) in the medium was determined by ELISA. The production of 8-epi-PGF(2α) decreased by greater than 90% during hypoxia, Upon reoxygenation 8-epi-PGF(2α) production increased linearly for 90 min reaching nearly 3 times normoxic levels. When added to the medium during reoxygenation, neither superoxide dismutase nor Tiron, a cell-permeable superoxide scavenger, inhibited 8-epi-PGF(2α) production. However, 8-epi-PGF(2α) production was inhibited by catalase. The production of 8-epi-PGF(2α), was also inhibited by indomethacin and aspirin. Exogenous hydrogen peroxide stimulated 8-epi-PGF(2α) production by normoxic cells, and aspirin inhibited the hydrogen peroxide-mediated increase in 8-epi-PGF(2α) production. These results indicate that the reactive oxygen species responsible for 8-epi-PGF(2α) synthesis during reoxygenation is hydrogen peroxide and that in endothelial cells 8-epi-PGF(2α) synthesis is mediated by prostaglandin H2 synthase (PGHS). To verify the role of PGHS in 8-epi-PGF(2α) synthesis, human PGHS-1 was expressed in COS-7 cells, a PGHS negative cell line that does not synthesize 8-epi-PGF(2α). In the presence of exogenous arachidonic acid the COS-7 cells expressing human PGHS-1 produced substantial amounts of PGE2 and 8-epi-PGF(2α). These data indicate that human PGHS-1 can support the synthesis of 8-epi-PGF(2α),a and that 8-epi-PGF(2α) synthesis by cultured human endothelial cells during reoxygenation is dependent on the activity of PGHS-1.

Original languageEnglish (US)
Pages (from-to)747-754
Number of pages8
JournalBiochemical Journal
Volume344
Issue number3
DOIs
StatePublished - Dec 15 1999

Keywords

  • Endothelium
  • Hypoxia

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Watkins, M. T., Patton, G. M., Soler, H. M., Albadawi, H., Humphries, D. E., Evans, J. E., & Kadowaki, H. (1999). Synthesis of 8-epi-prostaglandin F(2α) by human endothelial cells: Role of prostaglandin H2 synthase. Biochemical Journal, 344(3), 747-754. https://doi.org/10.1042/0264-6021:3440747