Induction of cyclo-oxygenase-2 in human endothelial cells by SIN-1 in the absence of prostaglandin production.
Nitric oxide (NO) regulates cyclo-oxygenase (COX) activity in various cell systems and reports conflict in regard to its stimulatory versus inhibitory role. Incubation of human umbilical vein endothelial cells (HUVEC) with SIN-1 (3-morpholinosydnonimine), a donor of NO, resulted in a rapid and dose-dependent increase in the expression of COX-2 as analysed by Western and Northern blotting. Incubation of HUVEC with SIN-1 and interleukine (IL)-1alpha resulted in increased induction of COX-2 compared with IL-1alpha alone and corresponded to an additive effect. The COX-2 induction was dependent on a de novo synthesis since cycloheximide, an inhibitor of protein synthesis, blocked the enzyme expression. The increase in COX-2 expression was not accompanied by a corresponding change in prostaglandin (PG) production. However, the COX activity was partially recovered when immunoprecipitated COX-2 was incubated with arachidonic acid and haematin. Peroxynitrite, a highly reactive nitrogen molecule derived from the interaction of NO and superoxide anion, significantly increased COX-2 expression. Under these conditions and within the limit of detection of the antibody, selective antibody for nitrotyrosine failed to detect nitrated COX-2 in immunoprecipitated COX-2 when cells where incubated with SIN-1 or SIN-1+IL-1alpha. Ro 31-8220, a specific inhibitor of protein kinase (PK) C, blocked the induction of COX-2. Also, SB203580, the selective inhibitor of p38 MAP kinase, strongly blocked the induction of COX-2 by SIN-1 in the presence or absence of IL-1alpha, whereas the MEK-1 inhibitor, PD 98059, affected it to a lesser extent. These data demonstrate that SIN-1 induces COX-2 in HUVEC in the absence of PG formation and suggest a complex regulation of COX-2 expression and PG formation by NO in endothelial cells.
Eligini
S
S
U 348 INSERM, I.F.R.6 Circulation-Paris 7, Hôpital Lariboisère 75475 Paris cedex 10, France.
Habib
A
A
Lebret
M
M
Créminon
C
C
Lévy-Toledano
S
S
Maclouf
J
J
D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D051546:Cyclooxygenase 2; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology*; D009566:Nitrates / Q000494:pharmacology; D011233:Precipitin Tests; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D011453:Prostaglandins / Q000096:biosynthesis*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D009566:Nitrates; D011453:Prostaglandins; D011725:Pyridines; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C039642:peroxynitric acid; C002385:linsidomine; D008981:Molsidomine; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one