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.
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.
Division of Cardiology, Department of Internal Medicine, Yuan's General Hospital, Kaohsiung, Taiwan.
Chung-Pin
CP
Liu
Department of Pediatrics, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Division of Pediatric Pulmonology and Cardiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
Zen-Kong
ZK
Dai
Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Chein-Heng
CH
Huang
Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Jwu-Lai
JL
Yeh
Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Bin-Nan
BN
Wu
Department of Pediatrics, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Division of Pediatric Pulmonology and Cardiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
Jiunn-Ren
JR
Wu
Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: ingjun@kmu.edu.tw.
Ing-Jun
IJ
Chen
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000097:blood / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D006976:Hypertension, Pulmonary / Q000150:complications / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D017380:Hypertrophy, Right Ventricular / Q000150:complications / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D016686:Monocrotaline; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D010880:Piperidines / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D011651:Pulmonary Artery / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D011687:Purines / Q000494:pharmacology; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D000068677:Sildenafil Citrate; D000071756:Soluble Guanylyl Cyclase; D013449:Sulfonamides / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014970:Xanthines / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D054460:rho-Associated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D019332:Endothelin-1; D010879:Piperazines; D010880:Piperidines; D011687:Purines; D018160:Receptors, Cytoplasmic and Nuclear; D043562:Receptors, G-Protein-Coupled; D013449:Sulfonamides; D014970:Xanthines; C439304:KMUP 1; D016686:Monocrotaline; D000068677:Sildenafil Citrate; D052250:Nitric Oxide Synthase Type III; D054460:rho-Associated Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D020742:rhoA GTP-Binding Protein; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase
Endothelial nitric oxide synthase; Endothelin-1; G-protein coupled receptors; Pulmonary artery hypertension; RhoA/Rho kinase