title: 8-Isoprostane-induced endothelin-1 production by infant rat pulmonary artery smooth muscle cells is mediated by Rho-kinase.
abstract: We have reported that 8-isoprostane stimulated the production of endothelin (ET)-1, a potent vasoconstrictor and critical mediator of chronic pulmonary hypertension, by infant rat pulmonary artery smooth muscle cells (PASMCs), through stimulation of the thromboxane A2 receptor. The aim of this study was to examine the contribution of putative downstream intracellular mediators of thromboxane A2 receptor stimulation to this effect. PASMCs from infant rats were treated with calcium ionophore (A23187), 8-isoprostane, or 8-isoprostane together with inhibitors of tyrosine kinase, protein kinase C, phosphatidylinositol 3-kinase, mitogen-activated protein kinases, or Rho-kinases (ROCK). A23187 had no effect on ET-1 production, excluding raised intracellular Ca2+ as a major contributor. Increased ET-1 production induced by 8-isoprostane was significantly attenuated by the ROCK inhibitors Y-27632 and hydroxyfasudil, but not by inhibitors of the other pathways. 8-Isoprostane also increased membrane binding of RhoA, a major determinant of ROCK activity, and ROCK-II expression through the protein kinase C pathway. These data indicate that the RhoA/ROCK pathway mediates increased ET-1 production by PASMCs, which we speculate may at least partly explain the beneficial effects of both antioxidants and ROCK inhibitors in animal models of chronic pulmonary hypertension.
authors.affiliation: Clinical Integrative Biology, Sunnybrook Research Institute, Toronto, ON, Canada.
authors.forename: Soojin L
authors.initials: SL
authors.lastname: Yi
authors.forename: Crystal
authors.initials: C
authors.lastname: Kantores
authors.forename: Rosetta
authors.initials: R
authors.lastname: Belcastro
authors.forename: Judy
authors.initials: J
authors.lastname: Cabacungan
authors.forename: A Keith
authors.initials: AK
authors.lastname: Tanswell
authors.forename: Robert P
authors.initials: RP
authors.lastname: Jankov
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D018929:Cell Culture Techniques; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000494:pharmacology; D019332:Endothelin-1 / Q000096:biosynthesis*; D004789:Enzyme Activation; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011480:Protease Inhibitors / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054460:rho-Associated Kinases
chemical_list: D019332:Endothelin-1; D047908:Intracellular Signaling Peptides and Proteins; D011480:Protease Inhibitors; C075750:8-epi-prostaglandin F2alpha; D000001:Calcimycin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D015237:Dinoprost; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C