title: Nitric oxide attenuates endothelin-1-induced activation of ERK1/2, PKB, and Pyk2 in vascular smooth muscle cells by a cGMP-dependent pathway.
abstract: Nitric oxide (NO), in addition to its vasodilator action, has also been shown to antagonize the mitogenic and hypertrophic responses of growth factors and vasoactive peptides such as endothelin-1 (ET-1) in vascular smooth muscle cells (VSMCs). However, the mechanism by which NO exerts its antimitogenic and antihypertrophic effect remains unknown. Therefore, the aim of this study was to determine whether NO generation would modify ET-1-induced signaling pathways involved in cellular growth, proliferation, and hypertrophy in A-10 VSMCs. Treatment of A-10 VSMCs with S-nitroso-N-acetylpenicillamine (SNAP) or sodium nitroprusside (SNP), two NO donors, attenuated the ET-1-enhanced phosphorylation of several key components of growth-promoting and hypertrophic signaling pathways such as ERK1/2, PKB, and Pyk2. On the other hand, inhibition of the endogenous NO generation with N(G)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, increased the ET-1-induced phosphorylation of these signaling components. Since NO mediates its effect principally through a cGMP-soluble guanylyl cyclase (sGC) pathway, we investigated the role of these molecules in NO action. 8-Bromoguanosine 3',5'-cyclic monophosphate, a nonmetabolizable and cell-permeant analog of cGMP, exhibited a effect similar to that of SNAP and SNP. Furthermore, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of sGC, reversed the inhibitory effect of NO on ET-1-induced responses. SNAP treatment also decreased the protein synthesis induced by ET-1. Together, these data demonstrate that NO, in a cGMP-dependent manner, attenuated ET-1-induced phosphorylation of ERK1/2, PKB, and Pyk2 and also antagonized the hypertrophic effects of ET-1. It may be suggested that NO-induced generation of cGMP contributes to the inhibition of ET-1-induced mitogenic and hypertrophic responses in VSMCs.
authors.affiliation: Laboratory of Cell Signaling, Montreal Diabetes Research Centre, Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Technopole Angus Campus, and Department of Medicine, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Ali
authors.initials: A
authors.lastname: Bouallegue
authors.forename: Grace Bou
authors.initials: GB
authors.lastname: Daou
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Srivastava
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000196:embryology / Q000201:enzymology / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006984:Hypertrophy / Q000201:enzymology / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000196:embryology / Q000201:enzymology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D010766:Phosphorylation; D014176:Protein Biosynthesis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000378:metabolism; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D015398:Signal Transduction; D000071756:Soluble Guanylyl Cyclase
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D010069:Oxadiazoles; D011810:Quinoxalines; D018160:Receptors, Cytoplasmic and Nuclear; D009599:Nitroprusside; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D019001:Nitric Oxide Synthase; D051418:Focal Adhesion Kinase 2; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D007930:Leucine; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester