Endothelial nitric oxide synthase-enhancing G-protein coupled receptor antagonist inhibits pulmonary artery hypertension by endothelin-1-dependent and endothelin-1-independent pathways in a monocrotaline model

• Published in: The Kaohsiung journal of medical sciences 2014-06, Vol.30 (6), p.267-278
• Main Authors: Liu, Chung-Pin, Dai, Zen-Kong, Huang, Chein-Heng, Yeh, Jwu-Lai, Wu, Bin-Nan, Wu, Jiunn-Ren, Chen, Ing-Jun
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Blood pressure; Blood Pressure - drug effects; Body Weight; Bosentan; Cell growth; Cyclic GMP-Dependent Protein Kinases - metabolism; Disease Models, Animal; Endothelial nitric oxide synthase; Endothelin; Endothelin-1; Endothelin-1 - blood; Endothelin-1 - metabolism; Endothelium; G proteins; G-protein coupled receptors; Guanylate Cyclase - metabolism; Heart enlargement; Heart Rate - drug effects; Hypertension; Hypertension, Pulmonary - complications; Hypertension, Pulmonary - enzymology; Hypertension, Pulmonary - pathology; Hypertension, Pulmonary - physiopathology; Hypertrophy, Right Ventricular - complications; Hypertrophy, Right Ventricular - enzymology; Hypertrophy, Right Ventricular - pathology; Hypertrophy, Right Ventricular - physiopathology; Immunohistochemistry; In Vitro Techniques; Instrument industry; Internal Medicine; Kinases; Male; Monocrotaline; Nitric oxide; Nitric Oxide Synthase Type III - metabolism; Pathogenesis; Physiological aspects; Piperazines - pharmacology; Piperidines - blood; Piperidines - pharmacology; Piperidines - therapeutic use; Protein kinases; Proteins; Pulmonary arteries; Pulmonary Artery - drug effects; Pulmonary Artery - pathology; Pulmonary Artery - physiopathology; Pulmonary artery hypertension; Purines - pharmacology; Rats, Wistar; Receptors, Cytoplasmic and Nuclear - metabolism; Receptors, G-Protein-Coupled - antagonists & inhibitors; Receptors, G-Protein-Coupled - metabolism; rho-Associated Kinases - metabolism; rhoA GTP-Binding Protein - metabolism; RhoA/Rho kinase; Signal Transduction - drug effects; Sildenafil Citrate; Smooth muscle; Soluble Guanylyl Cyclase; Sulfonamides - pharmacology; Thoracic surgery; Vasoconstriction - drug effects; Veins & arteries; Xanthines - blood; Xanthines - pharmacology; Xanthines - therapeutic use
• ISSN: 1607-551X; 2410-8650
• DOI: 10.1016/j.kjms.2014.02.014

Abstract This study investigates whether endothelin-1 (ET-1) mediates monocrotaline (MCT)-induced pulmonary artery hypertension (PAH) and right ventricular hypertrophy (RVH), and if so, whether the G-protein coupled receptor antagonist KMUP-1 (7-{2-[4-(2-chlorobenzene)piperazinyl]ethyl}-1,3-dimethylxanthine) inhibits ET-1-mediated PA constriction and the aforementioned pathological changes. In a chronic rat model, intraperitoneal MCT (60 mg/kg) induced PAH and increased PA medial wall thickening and RV/left ventricle + septum weight ratio on Day 21 after MCT injection. Treatment with sublingual KMUP-1 (2.5 mg/kg/day) for 21 days prevented these changes and restored vascular endothelial nitric oxide synthase (eNOS) immunohistochemical staining of lung tissues. Western blotting analysis demonstrated that KMUP-1 enhanced eNOS, soluble guanylate cyclase, and protein kinase G levels, and reduced ET-1 expression and inactivated Rho kinase II (ROCKII) in MCT-treated lung tissue over long-term administration. In MCT-treated rats, KMUP-1 decreased plasma ET-1 on Day 21. KMUP-1 (3.6 mg/kg) maximally appeared at 0.25 hours in the plasma and declined to basal levels within 24 hours after sublingual administration. In isolated PA of MCT-treated rats, compared with control and pretreatment with l -NG-nitroarginine methyl ester (100 μM), KMUP-1 (0.1–100 μM) inhibited ET-1 (0.01 μM)-induced vasoconstriction. Endothelium-denuded PA sustained higher contractility in the presence of KMUP-1. In a 24-hour culture of smooth muscle cells (i.e., PA smooth muscle cells or PASMCs), KMUP-1 (0.1–10 μM) inhibited RhoA- and ET-1-induced RhoA activation. KMUP-1 prevented MCT-induced PAH, PA wall thickening, and RVH by enhancing eNOS and suppressing ET-1/ROCKII expression. In vitro , KMUP-1 inhibited ET-1-induced PA constriction and ET-1-dependent/independent RhoA activation of PASMCs. In summary, KMUP-1 attenuates ET-1-induced/ET-1-mediated PA constriction, and could thus aid in the treatment of PAH caused by MCT.