Article date: July 1996
By: Paola Patrignani, Giovanna Santini, Maria R. Panara, Maria G. Sciulli, Anita Greco, Maria T. Rotondo, Maria Giamberardino, Jacques Maclouf, Giovanni Ciabattoni, Carlo Patrono, in Volume 118, Issue 5, pages 1285-1293
The isoprostane 8‐epi‐prostaglandin (PG)F2α is produced by free radical‐catalyzed peroxidation of arachidonic acid. It may also be formed as a minor product of the cyclo‐oxygenase activity of platelet PGH synthase (PGHS)‐1. We investigated 8‐epi‐PGF2α production associated with induction of the human monocyte PGHS‐2 and its pharmacological modulation.
Heparinized whole blood samples were drawn from healthy volunteers, 48 h following oral dosing with aspirin 300 mg to suppress platelet cyclo‐oxygenase activity. One ml aliquots were incubated with lipopolysaccharide (LPS: 0.1–50 μg ml−1) for 0–24 h at 37°C. PGE2 and 8‐epi‐PGF2α were measured in separated plasma by radioimmunoassay and enzyme immunoassay techniques.
Levels of both eicosanoids were undetectable (i.e. < 60 pg ml−1) at time 0. LPS induced the formation of PGE2 and 8‐epi‐PGF2α in a time‐ and concentration‐dependent fashion, coincident with the induction of PGHS‐2 detected by Western blot analysis of monocyte lysates. After 24 h at 10 μg ml−1 LPS, immunoreactive PGE2 and 8‐epi‐PGF2α averaged 10,480 ± 4,643 and 295 ± 140 pg ml−1 (mean ± s.d., n = 6), respectively.
Dexamethasone and 5‐methanesulphonamido‐6‐(2, 4‐difluorothiophenyl)‐1‐indanone (L‐745,337), a selective inhibitor of the cyclo‐oxygenase activity of PGHS‐2, reduced PGE2 and 8‐epi‐PGF2α production in response to LPS.
Isolated monocytes produced PGE2 and 8‐epi‐PGF2α in response to LPS (10 μg ml−1) in a time‐dependent fashion. Monocyte PGE2 and 8‐epi‐PGF2α production was largely prevented by dexamethasone (2 μm) and cycloheximide (10 μg ml−1) in association with suppression of PGHS‐2 but not of PGHS‐1 expression.
We conclude that the induction of PGHS‐2 in human monocytes is associated with cyclo‐oxygenase‐dependent generation of the vasoconstrictor and platelet‐agonist 8‐epi‐PGF2α.
The isoprostane 8‐epi‐prostaglandin (PG)F2α is produced by free radical‐catalyzed peroxidation of arachidonic acid. It may also be formed as a minor product of the cyclo‐oxygenase activity of platelet PGH synthase (PGHS)‐1. We investigated 8‐epi‐PGF2α production associated with induction of the human monocyte PGHS‐2 and its pharmacological modulation.
Heparinized whole blood samples were drawn from healthy volunteers, 48 h following oral dosing with aspirin 300 mg to suppress platelet cyclo‐oxygenase activity. One ml aliquots were incubated with lipopolysaccharide (LPS: 0.1–50 μg ml−1) for 0–24 h at 37°C. PGE2 and 8‐epi‐PGF2α were measured in separated plasma by radioimmunoassay and enzyme immunoassay techniques.
Levels of both eicosanoids were undetectable (i.e. < 60 pg ml−1) at time 0. LPS induced the formation of PGE2 and 8‐epi‐PGF2α in a time‐ and concentration‐dependent fashion, coincident with the induction of PGHS‐2 detected by Western blot analysis of monocyte lysates. After 24 h at 10 μg ml−1 LPS, immunoreactive PGE2 and 8‐epi‐PGF2α averaged 10,480 ± 4,643 and 295 ± 140 pg ml−1 (mean ± s.d., n = 6), respectively.
Dexamethasone and 5‐methanesulphonamido‐6‐(2, 4‐difluorothiophenyl)‐1‐indanone (L‐745,337), a selective inhibitor of the cyclo‐oxygenase activity of PGHS‐2, reduced PGE2 and 8‐epi‐PGF2α production in response to LPS.
Isolated monocytes produced PGE2 and 8‐epi‐PGF2α in response to LPS (10 μg ml−1) in a time‐dependent fashion. Monocyte PGE2 and 8‐epi‐PGF2α production was largely prevented by dexamethasone (2 μm) and cycloheximide (10 μg ml−1) in association with suppression of PGHS‐2 but not of PGHS‐1 expression.
We conclude that the induction of PGHS‐2 in human monocytes is associated with cyclo‐oxygenase‐dependent generation of the vasoconstrictor and platelet‐agonist 8‐epi‐PGF2α.
DOI: 10.1111/j.1476-5381.1996.tb15535.x
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