title: Long-term inhibition of RhoA attenuates vascular contractility by enhancing endothelial NO production in an intact rabbit mesenteric artery.
abstract: RhoA plays a critical role in regulating NO production in cultured endothelial cells. To determine its role in in situ endothelial cells, we investigated the effects of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors and a RhoA-binding domain of Rho-kinase (RB) on vascular contractility in the isolated rabbit mesenteric artery. Ex vivo treatment of the strips with 3x10(-5) mol/L simvastatin and fluvastatin for approximately 24 to 30 hours significantly attenuated the contractile response to phenylephrine and high K+ in the presence of endothelium. The addition of N(omega)-nitro-L-arginine methyl ester and the removal of endothelium abolished the attenuation of the contractile response. The cotreatment with geranylgeranyl pyrophosphate prevented the statin-induced attenuation of the contractile response, whereas geranylgeranyl transferase inhibitor mimicked the effect of simvastatin. Treatment with simvastatin enhanced the bradykinin-induced endothelium-dependent relaxation in the mesenteric artery, whereas it had no effect on the bradykinin-induced [Ca2+]i elevation in endothelial cells of the aortic valves. Introduction of RB to the strips using a cell-penetrating peptide of Tat protein (TATHA-RB) attenuated the contractile responses in a NO-dependent manner. However, a Rac1/Cdc42-binding fragment of p21-activated protein kinase, RB without Tat peptide or TATHA-protein A had no effect. The in vivo treatment of rabbit with simvastatin and TATHA-RB attenuated the contractility in a NO-dependent manner. Simvastatin and TATHA-RB significantly upregulated eNOS in the rabbit mesenteric artery. The present study provides the first evidence that RhoA plays a physiological role in suppressing NO production in in situ endothelial cells.
authors.affiliation: Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Shiga
authors.forename: Katsuya
authors.initials: K
authors.lastname: Hirano
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hirano
authors.forename: Junji
authors.initials: J
authors.lastname: Nishimura
authors.forename: Hajime
authors.initials: H
authors.lastname: Nawata
authors.forename: Hideo
authors.initials: H
authors.lastname: Kanaide
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015696:Gene Products, tat / Q000737:chemistry; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III; D010455:Peptides / Q000378:metabolism; D017368:Protein Prenylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011817:Rabbits; D019821:Simvastatin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D054462:p21-Activated Kinases; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D015696:Gene Products, tat; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; D009569:Nitric Oxide; D019821:Simvastatin; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein; D001920:Bradykinin; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester