Dual regulation of PLA2 and PGI2 production by G proteins in bovine aortic endothelial cells

Moti Rosenstock, Abraham Danon, Gilad Rimon

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

NaF, a nonselective activator of heterotrimeric guanine nucleotide- binding proteins (G proteins), increased the release of arachidonic acid (AA) and prostacyclin (PGI2) production in bovine aortic endothelial cells (BAEC) at low concentrations (40-60 mM). On the other hand, higher concentrations (100 mM) inhibited phospholipase A2 (PLA2) compared with the basal activity. Intracellular Ca2+ levels did not rise after treatment with stimulatory concentrations of NaF, and, moreover, neither neomycin nor Ca2+-free medium affected the biphasic pattern of PGI2 synthesis in response to NaF CGP-43187, an inhibitor of the 14-kDa secretory PLA2, did not affect NaF-induced AA release. However, AACOCF3, a specific inhibitor of the cytosolic 85-kDa PLA2 (cPLA2), abrogated AA release and PGI2 production in response to 60 mM NaF. A biphasic pattern of PGI2 production was also obtained with the guanosine 5'-triphosphate analogues guanosine 5'- O-(3-thiotriphosphate) and guanylylimidodiphosphate in permeabilized BAEC. Pretreatment of the cells with guanosine 5'-O-(2-thiodiphosphate) suppressed the inhibition and the stimulation of AA release induced by guanylylimidodiphosphate. In addition, phenylisopropyl adenosine inhibited the release of AA and PGI2, whereas ATP and bradykinin increased PGI2. Pertussis toxin not only inhibited ATP- and bradykinin-stimulated PGI2 release, it also reversed the inhibitory effect of phenylisopropyl adenosine, resulting in a significant stimulation. These findings strongly suggest that, in BAEC, cPLA2 is coupled with more than one G protein that are involved in inhibition and stimulation of cPLA2 activity.

Original languageEnglish
Pages (from-to)C555-C562
JournalAmerican Journal of Physiology - Cell Physiology
Volume271
Issue number2 40-2
DOIs
StatePublished - 1 Jan 1996

Keywords

  • arachidonic acid
  • guanyl nucleotides
  • pertussis toxin
  • phenylisopropyl adenosine
  • phospholipase A
  • prostacyclin
  • sodium fluoride

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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