We aimed at evaluating the relative contribution of cyclooxygenase (COX) -1 and COX-2 to the synthesis of prostacyclin in endothelial cells under static conditions in the presence or absence of exogenous arachidonic acid and/or altered intracellular redox balance. Selective inhibitors of either COX-1 (SC560 and FR122047) or COX-2 (SC236) concentration dependently (1-300 nM) reduced basal and interleukin (IL) -1|β-induced prostacyclin production in human umbilical vein endothelial cells by 70% or more; compound selectivity was confirmed using a whole-blood assay (IC50 COX-1/COX-2: 13 nM/930 nM for SC-560;9 μxM/457 nM for SC-236). The observed concomitant formation of isoprostane appeared to be associated with COX enzyme activity, while formation of COX-1/COX-2 heterodimers was detected by immunoprecipitation. In the presence of arachidonic acid and 12-hydroperoxy-eicosatetraenoic acid, either exogenous or provided by platelet activation, or after glutathione depletion, COX-1 inhibition but not COX-2 inhibition concentration dependently decreased prostacyclin production. Both isoforms appear to contribute to basal prostacyclin production by endothelial cells, with COX-2 providing the hydroperoxide tone required for COX-1 activity. Conversely, in the case of intracellular glutathione depletion or enhanced availability of arachidonic acid and hydroperoxides, selective COX-2 inhibition did not significantly affect the production of endothelial prostacyclin. These findings contribute to a better understanding of the effects of cyclooxygenase inhibitors on prostacyclin production.

Critical role of COX-1 in prostacyclin production by human endothelial cells under modification of hydroperoxide tone / C. Bolego, C. Buccellati, A. Prada, R.M. Gaion, G. Folco, A. Sala. - In: THE FASEB JOURNAL. - ISSN 0892-6638. - 23:2(2009 Feb), pp. 605-612.

Critical role of COX-1 in prostacyclin production by human endothelial cells under modification of hydroperoxide tone

C. Bolego
Primo
;
C. Buccellati
Secondo
;
G. Folco
Penultimo
;
A. Sala
Ultimo
2009

Abstract

We aimed at evaluating the relative contribution of cyclooxygenase (COX) -1 and COX-2 to the synthesis of prostacyclin in endothelial cells under static conditions in the presence or absence of exogenous arachidonic acid and/or altered intracellular redox balance. Selective inhibitors of either COX-1 (SC560 and FR122047) or COX-2 (SC236) concentration dependently (1-300 nM) reduced basal and interleukin (IL) -1|β-induced prostacyclin production in human umbilical vein endothelial cells by 70% or more; compound selectivity was confirmed using a whole-blood assay (IC50 COX-1/COX-2: 13 nM/930 nM for SC-560;9 μxM/457 nM for SC-236). The observed concomitant formation of isoprostane appeared to be associated with COX enzyme activity, while formation of COX-1/COX-2 heterodimers was detected by immunoprecipitation. In the presence of arachidonic acid and 12-hydroperoxy-eicosatetraenoic acid, either exogenous or provided by platelet activation, or after glutathione depletion, COX-1 inhibition but not COX-2 inhibition concentration dependently decreased prostacyclin production. Both isoforms appear to contribute to basal prostacyclin production by endothelial cells, with COX-2 providing the hydroperoxide tone required for COX-1 activity. Conversely, in the case of intracellular glutathione depletion or enhanced availability of arachidonic acid and hydroperoxides, selective COX-2 inhibition did not significantly affect the production of endothelial prostacyclin. These findings contribute to a better understanding of the effects of cyclooxygenase inhibitors on prostacyclin production.
12-HpETE; COX-2 heterodimers; Isoprostanes; Prostaglandin; Selective cyclooxygenase inhibitors
Settore BIO/14 - Farmacologia
feb-2009
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/61821
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