Role of cyclooxygenase 2, p38 and p42/44 MAPK in the secretion of prostacyclin induced by epidermal growth factor, endothelin-1 and angiotensin II in rat ventricular cardiomyocytes.
We studied the respective roles of cyclooxygenases (COX) isoforms as well as the p38 and p42/44 MAP kinase cascades in angiotensin II (AngII)-, endothelin-1 (ET-1)- and epidermal growth factor (EGF)-induced prostacyclin (PGI(2)) secretion in neonatal rat ventricular cardiomyocytes. Exposure of these cells for 1 h to 100 nM AngII, ET-1 or EGF resulted in an increase in prostacyclin formation which was abolished by the COX-2 specific inhibitor NS-398 (1 microM), while the COX-1 inhibitor valeryl salicylate (5 microM) had no effect. Agonist-induced prostacyclin secretion was also abolished in the presence of cycloheximide (10 microg/ml), indicating that newly synthesized proteins are necessary for this response. In this context, the COX-2 protein amount was significantly increased following 1 h incubation of cardiomyocytes, with AngII, ET-1 and EGF. These results indicate that in cardiomyocytes AngII, ET-1 and EGF induce both the synthesis and the activity of COX-2. Investigating the role of MAPK in the stimulation of prostacyclin induced by these three agonists, we found that both the p42/44 MAPK inhibitor PD 98059 (50 microM) and the p38 MAPK blocker SB 203580 (5 microM) prevented agonist-induced PGI(2) secretion without affecting COX-2 activity or synthesis. Our results show that p42/44 and p38 MAPK activation is at the basis of AngII-, ET-1- and EGF-induced prostacyclin secretion in cardiomyocytes. They further suggest that these MAPK act on a target(s) located upstream of COX-2.
Rebsamen
Michela C
MC
Division of Endocrinology and Diabetology, University Hospital, 24, rue Micheli-du-Crest, CH-1211 14, Geneva, Switzerland.
Capoccia
Romina
R
Vallotton
Michel B
MB
Lang
Ursula
U
D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D051546:Cyclooxygenase 2; D019332:Endothelin-1 / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism; D011464:Epoprostenol / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D051381:Rats; D048051:p38 Mitogen-Activated Protein Kinases
D019332:Endothelin-1; D007527:Isoenzymes; D000804:Angiotensin II; D004815:Epidermal Growth Factor; D011464:Epoprostenol; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases