Urocortin II induces nitric oxide production through cAMP and Ca2+ related pathways in endothelial cells.
BACKGROUND
Urocortin II has previously been shown in anesthetized pigs to increase coronary blood flow through activation of the endothelial nitric oxide synthase (eNOS) pathway and involvement of the subtype 2 of corticotropin releasing factor receptors (CRFR2). However, little information has been available regarding the intracellular signalling through these receptors and leading to the release of nitric oxide (NO).


OBJECTIVE
The present study was therefore planned to determine the mechanism involved in such signalling.


METHODS
In porcine aortic endothelial cells (PAE) the effects of urocortin II on NO production and ERK, Akt, p38 and eNOS phosphorylation were examined in absence or presence of the adenylyl cyclase agonist forskolin and antagonist 2'5' dideoxyadenosine, the Ca2+ ionophore A23187, the Ca2+-calmodulin-kinase inhibitor KN93, the CRFR2 blocker astressin 2B and of the protein kinases specific inhibitors UO126, wortmannin and SB203580.


RESULTS
Urocortin II caused a significant increase of NO production, which was amplified by forskolin and A23187 (P <0.05). All effects of urocortin II were abolished by l-NAME, 2'5' dideoxyadenosine, KN93, astressin 2B and by pre-treatment of cells with UO126, wortmannin and SB203580. Western Blot analysis confirmed the involvement of ERK, Akt and p38 in the eNOS activation.


CONCLUSIONS
In PAE urocortin II interaction with CRFR2 caused a cAMP-dependent and Ca2+-related phoshorylation of ERK, Akt and p38 leading to eNOS activation.
Grossini
Elena
E
Laboratorio di Fisiologia, Dipartimento di Medicina Clinica e Sperimentale, Facoltà di Medicina e Chirurgia, Università del Piemonte Orientale 'A. Avogadro', Novara, Italy. grossini@med.unipmn.it
Molinari
Claudio
C
Mary
David A S G
DA
Uberti
Francesca
F
Ribichini
Flavio
F
Caimmi
Philippe Primo
PP
Vacca
Giovanni
G
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D016048:Dideoxyadenosine / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D009570:Nitriles / Q000494:pharmacology; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013552:Swine; D054832:Urocortins / Q000494:pharmacology*; D000077191:Wortmannin; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D000730:Androstadienes; D002070:Butadienes; D007093:Imidazoles; D007476:Ionophores; D009570:Nitriles; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D011725:Pyridines; C113580:U 0126; D054832:Urocortins; C528574:astressin-2B; D005576:Colforsin; D009569:Nitric Oxide; D000001:Calcimycin; D016048:Dideoxyadenosine; D000242:Cyclic AMP; D051058:Oncogene Protein v-akt; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; D002118:Calcium; D000077191:Wortmannin