BACKGROUND AND OBJECTIVES: Elevated endothelin (ET)-1 level is strongly correlated with the pathogenesis of pulmonary arterial hypertension (PAH). Expression level of nicotinamide adenine dinucleotide phosphate oxidase (NOX) 4 is increased in the PAH patients. Ambrisentan, a selective endothelin receptor A (ERA) antagonist, is widely used in PAH therapy. The current study was undertaken to evaluate the effects of ambrisentan treatment in the monocrotaline (MCT)-induced PAH rat model. METHODS: Rats were categorized into control group (C), monocrotaline group (M) and ambrisentan group (Am). The M and Am were subcutaneously injected 60 mg/kg MCT at day 0, and in Am, ambrisentan was orally administered the day after MCT injection for 4 weeks. The right ventricle (RV) pressure was measured and pathological changes of the lung tissues were observed by Victoria blue staining. Protein expressions of ET-1, ERA, endothelial nitric oxide synthase (eNOS) and NOX4 were confirmed by western blot analysis. RESULTS: Ambrisentan treatment resulted in a recovery of the body weight and RV/left ventricle+septum at week 4. The RV pressure was lowered at weeks 2 and 4 after ambrisentan administration. Medial wall thickening of pulmonary arterioles and the number of intra-acinar arteries were also attenuated by ambrisentan at week 4. Protein expression levels of ET-1 and eNOS were recovered at weeks 2 and 4, and ERA levels recovered at week 4. CONCLUSIONS: Ambrisentan administration resulted in the recovery of ET-1, ERA and eNOS protein expression levels in the PAH model. However, the expression level of NOX4 remained unaffected after ambrisentan treatment.
Animals ; Arteries ; Arterioles ; Blotting, Western ; Body Weight ; Endothelin Receptor Antagonists ; Endothelins ; Gene Expression ; Heart Ventricles ; Humans ; Hypertension ; Hypertension, Pulmonary ; Lung ; Models, Animal ; Monocrotaline ; NADP ; NADPH Oxidase ; Nitric Oxide Synthase Type III ; Oxidoreductases ; Rats ; Receptors, Endothelin ; Victoria

The study is to investigate the effect of angiotensin II (Ang II) and its receptor blockers on migration and endothelin-1 (ET-1) expression of rat vascular adventitial fibroblast subpopulations. Vascular adventitial fibroblasts were individually expanded by using cloning rings, and the effects of Ang II on the migration of adventitial fibroblast subpopulations were evaluated by Transwell. Fluorescence quantitative-PCR detected the expression of preproET-1 mRNA induced by Ang II, and its receptor antagonists losartan and PD-123319. The concentration of ET-1 was determined by ELISA. It showed that spindle shaped and epithelioid shaped cells were isolated by using cloning rings, named as spindle cells and round cells. RT-PCR showed that fibroblast subpopulations did not have leukocytes, endothelial cells and smooth muscle cells, namely pure cell lines. Compared with respective control cells, two subpopulations had transferring ability. Ang II significantly improved round cells migration in a concentration-dependent manner, and had no obvious influence on spindle cells migration. Ang II (1 x 10(-8) - 1 x 10(-6) mol x L(-1)) significantly increased the expression of preproET-1 mRNA in round cells (P < 0.01), and had no significant effect on the expression of preproET-1 mRNA in spindle cells. Losartan blocked the expression of preproET-1 mRNA induced by Ang II in round cells, and had no significant effect on the expression of preproET-1 mRNA in spindle cells. The effects of Ang II and ET-1 receptor inhibitors on the release of ET-1 were similar to the expression of preproET-1 mRNA. The results indicate that there are two cell subpopulations: round cells and spindle cells in rat vascular adventitial fibroblasts. Ang II significantly improved cells migration, and increased the expression of ET-1 in round cell subpopulation. It suggested that there may be different migratory mechanisms in two cell subpopulations, and the two subpopulations may play a different role in vascular remodeling and reparative process.
Angiotensin II ; pharmacology ; Angiotensin Receptor Antagonists ; pharmacology ; Animals ; Cell Movement ; drug effects ; Cells, Cultured ; Endothelin-1 ; genetics ; metabolism ; Fibroblasts ; cytology ; metabolism ; Imidazoles ; pharmacology ; Losartan ; pharmacology ; Male ; Pyridines ; pharmacology ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vasoconstrictor Agents ; pharmacology

The purpose of this study was to investigate the therapeutic effects of small hairpin RNA (shRNA) targeting endothelin-converting enzyme (ECE)-1 in monocrotaline (MCT)-induced pulmonary hypertensive rats. Ninty-four Sprague-Dawley rats were divided into three groups: control (n = 24), MCT (n = 35) and shRNA (n = 35). Four-week survival rate in the shRNA group was significantly increased compared to that in the MCT group. The shRNA group showed a significant improvement of right ventricular (RV) pressure compared with the MCT group. The MCT and shRNA groups also showed an increase in RV/(left ventricle + septum) ratio and lung/body weight. Plasma endothelin (ET)-1 concentrations in the shRNA group were lower than those in the MCT group. Medial wall thickness of pulmonary arterioles were increased after MCT injection and was significantly decreased in the shRNA group. The number of intra-acinar muscular pulmonary arteries was decreased in the shRNA group. The mRNA expressions of ET-1 and ET receptor A (ETA) were significantly decreased in the shRNA group in week 4. The protein levels of ETA were decreased in the shRNA group in week 2. The protein levels of tumor necrosis factor-alpha and vascular endothelial growth factor were decreased in the shRNA group in week 4. In conclusion, the gene silencing with lentiviral vector targeting ECE-1 could be effective against hemodynamic, histopathological and gene expression changes in pulmonary hypertension.
Animals ; Aspartic Acid Endopeptidases/*antagonists & inhibitors/blood/genetics ; Body Weight ; Heart Ventricles/physiopathology ; Hypertension, Pulmonary/chemically induced/*enzymology/mortality ; Lentivirus/genetics ; Lung/anatomy & histology/metabolism/pathology ; Male ; Metalloendopeptidases/*antagonists & inhibitors/blood/genetics ; Monocrotaline/toxicity ; Pulmonary Artery/drug effects/physiopathology ; RNA, Small Interfering/*metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin A/genetics/metabolism ; Survival Rate ; Tumor Necrosis Factor-alpha/metabolism ; Vascular Endothelial Growth Factor A/metabolism

BACKGROUNDIt has been shown that neurohumoral factors other than mechanical obstruction are involved in the pathophysiology of acute pulmonary thromboembolism (APTE). The aim of this study was to investigate the effects of thrombolytic drugs, a selective endothelin-1 receptor (ET-1R) antagonist alone or their combination on APTE in a canine model.

METHODSTwenty dogs were randomly assigned to five groups: sham, model, urokinase (UK), BQ123, and combination (UK plus BQ123). The dogs in the sham group underwent sham surgery. APTE was induced in the other four groups by intravenous injection of autologous blood clots. Dogs in the UK, BQ123 and combination groups received UK, BQ123 (a selective ET-1R antagonist), or UK plus BQ123, respectively. The dogs in the model group were given saline. Mean pulmonary artery pressure (mPAP), serum concentrations of ET-1, thromboxane (TXB2), and tumor necrosis factor (TNF)-alpha were determined at different time points following the induction of APTE.

RESULTSUK and BQ123 alone markedly decreased mPAP in APTE. By comparison, the reduction was more significant in the combination group. Compared with the sham group ((-0.90 +/- 0.61) mmHg), mPAP increased by (7.44 +/- 1.04), (3.42 +/- 1.12) and (1.14 +/- 0.55) mmHg in the model group, UK alone and BQ123 alone groups, respectively, and decreased by (2.24 +/- 0.67) mmHg in the combination group (P < 0.01). Serum ET-1 concentrations in the BQ123 and combination groups were (52.95 +/- 8.53) and (74.42 +/- 10.27) pg/ml, respectively, and were significantly lower than those in the model and UK groups ((84.56 +/- 7.44) and (97.66 +/- 8.31) pg/ml respectively; P < 0.01). Serum TNF-alpha concentrations were significantly lower in the BQ123 group than in the model, UK and combination groups (P < 0.05).

CONCLUSIONSOur results indicate that the selective ET-1R antagonist BQ123 not only reduces the increase of mPAP and serum ET-1 level, but also inhibits the production of TNF-alpha, and attenuates the local inflammatory response induced by APTE. Selective ET-1R antagonists may be beneficial to the treatment of APTE, particularly when used in combination with a thrombolytic agent.

Animals ; Dogs ; Endothelin A Receptor Antagonists ; Endothelin-1 ; blood ; Fibrinolytic Agents ; therapeutic use ; Peptides, Cyclic ; therapeutic use ; Pulmonary Embolism ; blood ; drug therapy ; pathology ; Random Allocation ; Thromboxanes ; blood ; Tumor Necrosis Factor-alpha ; blood

Three-dimensional pharmacophore models were generated for AT1 and ET(A) receptors based on highly selective AT1 and ET(A) antagonists using the program Catalyst/HipHop. Both the best pharmacophore model for selective AT1 antagonists (Hypo-AT(1)-7) and ETA antagonists (Hypo-ET(A)-1) were obtained through a careful validation process. All five features contained in Hypo-AT(1)-7 and Hypo-ET(A)-1 (hydrogen-bond acceptor (A), hydrophobic aliphatic (Z), negative ionizable (N), ring aromatic (R), and hydrophobic aromatic (Y)) seem to be essential for antagonists in terms of binding activity. Dual AT1 and ET(A) receptor antagonists (DARAs) can map to both Hypo-AT(1)-7 and Hypo-ET(A)-1, separately. Comparison of Hypo-AT(1)-7 and Hypo-ET(A)-1, not only AT1 and ET(A) antagonist pharmacophore models consist of essential features necessary for compounds to be highly active and selective toward their corresponding receptor, but also have something in common. The results in this study will act as a valuable tool for designing and researching structural relationship of novel dual AT1 and ET(A) receptor antagonists.
Angiotensin II Type 1 Receptor Blockers ; chemistry ; Drug Design ; Endothelin Receptor Antagonists ; Models, Molecular ; Molecular Conformation

OBJECTIVETo investigate the anti-tumor effect of the endothelin A receptor antagonist BQ123 on human prostate cancer cell line PC-3M in vitro by observing its impact on the proliferation and apoptosis of human prostate cancer cells.

METHODSThe inhibiting effect of BQ123 on the proliferation of PC-3M cells was observed by MTT assay, erosion trace test and Transwell chamber chemotaxis assay, and its induction of their apoptosis determined by Annexin V-FITC/PI staining and cytometry.

RESULTSBQ123 exhibited increased inhibition of PC-3M cells in a time-dependent manner, with inhibition rates of 22.32%, 44.88% and 64.47% at 24 h, 48 h and 72 h, respectively (P < 0.05). The migration distances of the PC-3M cells in the BQ123 group were (103.42 +/- 75.63) microm, (243.75 +/- 121.53) microm and (422.07 +/- 36.01) microm at 12 h, 24 h and 48 h, obviously lower than (162.93 +/- 19.87) microm, (317.19 +/- 43.19) microm and (692.74 +/- 40.84) microm in the control group (P < 0.05). The number of the PC-3M cells that invaded the inferior chamber in the BQ123 group was (79.2 +/- 9.58), significantly decreased as compared with (92.6 +/- 5.94) in the control (P < 0.05). The apoptosis rate of PC-3M exposed to BQ123 was (15.03 +/- 0.93)%, significantly higher than (9.38 +/- 1.37)% in the control (P < 0.05). The ratio of PC-3M cells in different cycles showed no significant differences.

CONCLUSIONBQ123 inhibits the proliferation of PC-3M cells and induces their apoptosis in vitro, which may give a new idea on the studies of prostate cancer therapies.

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Endothelin A Receptor Antagonists ; Humans ; Male ; Peptides, Cyclic ; pharmacology ; Prostatic Neoplasms

Endothelin systems are believed to play important roles in the emergence and maintenance of functions of various organs during perinatal development, including the kidney. The present study was designed to investigate the roles of endothelin systems on physiologic renal growth and development. Newborn rat pups were treated with either Bristol-Myers Squibb-182874 (30 mg/kg/day), a selective endothelin A receptor (ET(A)R) antagonist, or vehicle for 7 days. To identify cellular changes, kidneys were examined for apoptotic cells by terminal deoxynucleotide transferasemediated nick-end labeling stain and proliferating cell nuclear antigen (PCNA) by immunohistochemical (IHC) stain. To clarify the molecular control of these processes, immunoblots and reverse transcriptase-polymerase chain reaction for Clusterin, Bcl-2, Bcl-X(L), Bax, and p53 were performed. ETAR antagonist treatment resulted in reduced kidney weights, decreased PCNA-positive proliferating cells, and increased apoptotic cells. The protein expressions of renal Bcl-X(L) and Bax in the ETAR antagonist-treated group were significantly decreased, whereas the mRNA expressions of these genes were not changed. There were no significant differences in the expressions of Clusterin, Bcl-2, and p53. In conclusion, inhibition of endogenous endothelins impairs renal growth, in which decreased cellular proliferation, increased apoptosis and decreased expressions of renal Bcl-X(L) and Bax are possibly implicated.
Animals ; Animals, Newborn ; Antihypertensive Agents/*pharmacology ; *Apoptosis ; *Cell Proliferation ; Dansyl Compounds/*pharmacology ; Gene Expression Regulation, Developmental/drug effects ; In Situ Nick-End Labeling ; Kidney/drug effects/*growth & development/*metabolism ; Proliferating Cell Nuclear Antigen/metabolism ; Proto-Oncogene Proteins c-bcl-2/genetics/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin A/*antagonists & inhibitors/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Suppressor Protein p53/genetics/metabolism ; bcl-X Protein/genetics/metabolism

Antihypertensive Agents ; therapeutic use ; Endothelin Receptor Antagonists ; therapeutic use ; Familial Primary Pulmonary Hypertension ; Humans ; Hypertension ; drug therapy ; Hypertension, Pulmonary ; drug therapy

Proteinuria is a cardinal manifestation of renal disease and has been proposed to promote progression of renal disease. Proteinuria develops in 9~41% of transplant recipients, and is diagnosed by routine urinalysis, urine protein to creatinine ratio, or 24-hour urine protein collection. Protein excretion of >200 mg/24 h is considered abnormal. The etiology of post-transplant proteinuria is diverse, including allograft rejection, recurrent or de novo glomerulonephritis, cyclosporine A nephrotoxicity, conversion to sirolimus, and chronic allograft nephropathy, which is the most common. Transplant renal biopsy is required to confirm the cause of proteinuria, and a combination of two or more of the transplant pathological categories can be present. High-grade proteinuria is believed to mediate progressive renal damage by conferring to proximal tubular epithelial cells with increased production of endothelin-1, chemokines such as monocyte chemoattractant protein-1 and cytokines, all of which promote interstitial fibrosis. It has been reported that proteinuria after renal transplantation affected not only graft survival but also patient survival. In proteinuric recipients, both the cardiovascular and noncardiovascular death risks seem to be significantly increased compared with nonproteinuric recipients. Low-grade (<1 g/24 h) proteinuria 1 year after transplantation is also associated with graft loss. The treatments for proteinuria are blood pressure control, and the use of angiotensin-converting enzyme inhibitor and/or angiotensin II receptor blockers therapy. Several options that are able to reduce proteinuia, including nondihydropyridine calcium channel blocker or aldosterone antagonists are also available. In conclusion, post-transplant proteinuria is a sensitive marker of graft dysfunction, correlated both to graft failure and to patient death. Appropriate management guided by proven cause and antiproteinuric treatments may improve the outcome.
Allografts ; Angiotensin Receptor Antagonists ; Biopsy ; Blood Pressure ; Calcium Channels ; Chemokine CCL2 ; Chemokines ; Creatinine ; Cyclosporine ; Cytokines ; Endothelin-1 ; Epithelial Cells ; Fibrosis ; Glomerulonephritis ; Graft Survival ; Humans ; Kidney Transplantation ; Mineralocorticoid Receptor Antagonists ; Proteinuria* ; Sirolimus ; Transplantation ; Transplants ; Urinalysis

AIMTo determine the involvement of extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in the expression of endothelin receptor type B (ETB) during culture.

METHODSSB386023, a specific inhibitor for ERK1/2 pathway, was used to define the intracellular signaling pathway for the upregulation of ETB receptors and sarafotoxin 6c (S6c), a selective agonist for ETB receptors, induced contraction in isolated rat superior mesenteric arteries. The contraction was recorded by a sensitive in vitro myograph and the receptor mRNA was quantified by a real-time PCR. The phosphorylated ERK1/2 proteins were analyzed by phosphoELISA assay.

RESULTSS6c induced strong contractile responses of the artery after culture for 24 h, while there was no response to S6c in fresh vessel segments. The enhanced contractile response to S6c paralleled with an increase of mRNA for ETB receptors. The phosphorylated ERK1/2 proteins significantly increased after culture for 3 h. After co-culture with SB386023 for 24 h, S6c-induced contractions significantly decreased with reduction of Emax from (217 +/- 14) % to (127 +/- 23) % (P <0.01). This response paralleled with a decreased level of ETB receptor mRNA.

CONCLUSIONERK1/2 pathway was involved in the up-regulation of ETB receptors on smooth muscle cells isolated from rat mesenteric arteries during culture.

Animals ; Cells, Cultured ; Male ; Mesenteric Arteries ; cytology ; Mitogen-Activated Protein Kinase 1 ; antagonists & inhibitors ; metabolism ; Mitogen-Activated Protein Kinase 3 ; antagonists & inhibitors ; metabolism ; Muscle Contraction ; drug effects ; Muscle, Smooth, Vascular ; cytology ; metabolism ; Organ Culture Techniques ; Phosphorylation ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin B ; biosynthesis ; genetics ; Signal Transduction ; Up-Regulation ; Vasoconstrictor Agents ; pharmacology ; Viper Venoms ; pharmacology