Animals ; Humans ; Ligands ; Polymorphism, Genetic ; Receptor Cross-Talk ; physiology ; Receptor, Angiotensin, Type 1 ; physiology ; Receptor, Angiotensin, Type 2 ; genetics ; physiology

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

PURPOSE: Angiotensin II plays a potent role in renal injury not only by vasoconstrictive effects but also by biochemical effects. We investigated the effect of angiotensin II on ZO-1 (zonular occludens-1), a component of the slit diaphragm domain connecting slit diaphragm structure and actin cytoskeleton, in the glomerular epithelial cells (podocytes) for the glomerular damage. We tried to find that this effect could be prevented by losartan, an angiotensin II type 1 receptor blocker. METHODS: Glomerular epithelial cells were treated with various concentrations of angiotensin II and losartan. The distribution of ZO-1 was observed by confocal microscope and the change of ZO-1 expression was measured by Western blotting and RT-PCR. RESULTS: The intensities of fluorescences and bands of ZO-1 protein were decreased by angiotensin II in a dose-dependent manner by confocal microscopy and Western blot analysis, respectively. ZO-1 also moved from peripheral to inner cytoplasm and lost its linear pattern. These distributional changes of ZO-1 protein by angiotensin II were reversed by losartan in a dose-dependent manner. Angiotensin II reduced the amount and mRNA expresssion of ZO-1 which were also reversed by losartan. CONCLUSION: Angiotensin II decreases the amount of ZO-1 protein and changes its localization through angiotensin II type 1 receptor. These findings suggest that angiotensin II-added condition induces the cytoplasmic translocation and suppresses the production of ZO-1 in podocytes at transcriptional level, and could be prevented by angiotensin receptor antagonists.
Actin Cytoskeleton ; Adherens Junctions ; Angiotensin II Type 1 Receptor Blockers ; Angiotensin II* ; Angiotensin Receptor Antagonists ; Angiotensins* ; Blotting, Western ; Cytoplasm ; Diaphragm ; Epithelial Cells* ; Losartan ; Microscopy, Confocal ; Podocytes ; Receptor, Angiotensin, Type 1 ; RNA, Messenger

BACKGROUND/AIMS: Fimasartan is an angiotensin type 1 receptor blocker (ARB) which has comparable efficacy and tolerability with other ARBs. The aim of this study was to evaluate 24-hour blood pressure (BP) lowering efficacy and the tolerability of the low dose fimasartan compared with valsartan in patients with mild to moderate hypertension. METHODS: This study was a phase II, prospective, multicenter, randomized, double-blind, parallel-grouped trial. A total of 75 hypertensive patients, whose mean ambulatory BP monitoring values were ≥ 135/85 mmHg, were randomized to either fimasartan 30 mg or valsartan 80 mg daily. The primary efficacy endpoint was the change in the mean 24-hour systolic BP (SBP) values from the baseline and at the week 8. Secondary endpoints included the change in the mean 24-hour diastolic BP values, the daytime and the nighttime mean BP values at week 8, the trough-to-peak (T/P) ratio and the smoothness index. RESULTS: At week 8, the mean 24-hour SBP values significantly decreased in both groups; –10.5 ± 11.9 mmHg (p < 0.0001) in the fimasartan group and –5.5 ± 11.6 mmHg (p = 0.0307) in the valsartan group. The difference between two groups was 4.3 ± 2.9 mmHg but there was no statistical significance (p = 0.1392). The global T/P ratio in the fimasartan 30 mg groups were 0.48 and 0.40 in the valsartan 80 mg group, respectively (p = 0.3411). The most frequent adverse events (AEs) were acute pharyngitis and there were no cases of severe AEs. CONCLUSIONS: In mild-to-moderate hypertensive patients, low dose (30 mg) fimasartan showed comparable 24-hour BP lowering efficacy compared with valsartan (80 mg). There was no difference in tolerability between two groups.
Angiotensin II Type 1 Receptor Blockers ; Blood Pressure Monitoring, Ambulatory ; Blood Pressure* ; Humans ; Hypertension* ; Pharyngitis ; Prospective Studies ; Receptor, Angiotensin, Type 1 ; Valsartan

To investigate the molecular mechanism of angiotensin II (Ang II) receptor activation in adult rat cardiac fibroblasts, the expressions of cell signal transduction-associated genes were studied by using cDNA microarray. Cardiac fibroblasts of adult Sprague-Dawley rats (230~250 g) were isolated and cultured. The cells were divided into 4 groups: Ang II, Ang II + losartan, Ang II + PD123319, Ang II + losartan + PD123319. The expressions of Ang II receptors were studied by immunohistochemical staining. Total RNA was extracted and purified. After cDNA synthesis and biotin-16-dUTP labeling, the probes were denatured and hybridized with GEArray Q Series mouse G Protein-coupled Receptors Signaling Pathway Finder Gene Array (MM-025) containing 96 genes associated with 11 pathways. The arrays were scanned with a Uniscand1000 scanner and further analyzed with GEArray Analyzer software. RT-PCR was used to further confirm the results of gene microarray. The results of immunohistochemical staining showed that the expression of Ang II type 2 (AT2) receptor was evidently induced by Ang II stimulation when Ang II type 1 (AT1) receptor was blocked. The results of gene array indicated that blocking AT1 receptor changed 34 genes (more than 2 folds), 30 were down-regulated and 4 were up-regulated. The maximum change was not beyond 20 folds. The following 9 pathways were activated: cAMP/PKA, Ca2+, PKC, PLC, MAPK, PI-3 kinase, NO-cGMP, Rho, NF-kappaB pathways. Blockade of AT2 receptor caused 64 genes changing more than 2 folds (48 were down-regulated and 16 were up-regulated). Eleven pathways were basically activated. The change of the following 7 genes was over 30 folds: Cyp19a1 (37 folds), Il1r2 (42 folds), Cflar (53 folds), Bcl21 (31 folds), Pik3cg (278 folds), Cdkn1a (90 folds), Agt (162 folds). According to the activated extent, the signal transduction pathways in turn were PI-3 kinase, NF-kappaB and JAK-STAT pathways. Blocking both AT1 and AT2 receptors changed 46 genes more than 2 folds (36 were down-regulated and 10 were up-regulated). Eleven pathways were basically activated. The results of RT-PCR of IL-1beta and TNF-alpha confirmed the observations in gene microarray. Our results show that Ang II can induce a high expression of AT2 receptor in adult rat cardiac fibroblasts when AT1 receptor is blocked, and the signal mechanism of AT2 receptor is clearly different from that of AT1 receptor.
Angiotensin II ; pharmacology ; Angiotensin Receptor Antagonists ; pharmacology ; Animals ; Fibroblasts ; metabolism ; Gene Expression ; Imidazoles ; pharmacology ; Losartan ; pharmacology ; Myocardium ; cytology ; Pyridines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 1 ; metabolism ; Receptor, Angiotensin, Type 2 ; metabolism ; Signal Transduction

Previously, we made a study report on the genotype disturbution and the gene frequency of angiotensin I-converting enzyme (ACE) in Korean population, and on the association between hypertension and genetic variance of ACE. This time, we have investigated a rapid mismatch-PCR/RFLP assays for the variant of the angiotensin II type 1 receptor (AT1R) gene (an A C transversion at position 1166 of AT1R gene), a mutation which may interact with the ACE polymorphism in the determining of risk of myocardial infarction. The genotype distributions of Koreans' angiotensin II type I receptor gene were AA (66.3%):AC (28.1%):CC (5.6%), thus the AA genotype was most numerous, and the allele frequency was A:C = 0.803:0.197. Genotype distributions were shown as AA (76.8%):AC (20.9%):CC (2.3%), the allele frequency was A:C = 0.872:0.128 in the male group, and AA (47.4%):AC (41.0%):CC (11.6%), A:C = 0.679:0.321 in the female group. Differences were highly significant between the male and female groups (p<0.0001). Genotype distributions between angiotensin II type I receptor gene and angiotensin converting enzyme gene showed that there is no significance between AT1R genotypes and ACE genotypes in total subjects (p>0.05).
Angiotensin II* ; Angiotensins* ; Female ; Gene Frequency ; Genotype ; Humans ; Hypertension ; Male ; Myocardial Infarction ; Peptidyl-Dipeptidase A* ; Polymorphism, Genetic ; Receptor, Angiotensin, Type 1*

OBJECTIVEIt has been shown that angiotensin converting enzyme inhibitors (ACEI) can reduce the ratio of pulmonary and systemic circulation blood flow (Qp/Qs) and thus decrease the blood flow of left-to-right shunt in children with left-to-right shunt congenital cardiac lesions. This suggests that there are differences in the expression of Angiotensin II receptors between systemic and pulmonary circulation. This study aimed to explore the differences of Angiotensin II receptors type 1 and type 2 (AT1 and AT2 receptors) expression between systemic and pulmonary circulation in children with left-to-right shunt congenital cardiac lesions.

METHODSLung and skeletal muscular tissues were obtained from 20 children with left-to-right shunt congenital cardiac lesions by biopsy during operation. The specimens were stained by immunohistochemistry techniques for AT1 and AT2 receptors. The technique of morphometric analysis was used to measure the immunoreactivity of AT1 and AT2 receptors (expressed by IOD values) of pulmonary, skeletal muscular and pleural small vascular wall the diameter of which was 15-100 microm.

RESULTSThe immunoreactivities of AT1 and AT2 receptors of pulmonary small vascular walls [(124 +/- 95)x10(3) and (85 +/- 62)x10(3) respectively] were significantly lower than those of skeletal muscular [(219 +/- 156)x10(3) and (155 +/- 139)x10(3) respectively] and those of pleural small vascular walls [(279 +/- 191)x10(3) and (175 +/- 128)x10(3) respectively] in children with left-to-right shunt congenital cardiac lesions (P < 0.05).

CONCLUSIONSThe expression of AT1 and AT2 receptors in small vascular walls of systemic circulation was higher than that of pulmonary circulation in children with left-to-right shunt congenital cardiac lesions.

Child ; Child, Preschool ; Female ; Heart Defects, Congenital ; blood ; Humans ; Immunohistochemistry ; Infant ; Male ; Pulmonary Circulation ; Receptor, Angiotensin, Type 1 ; blood ; Receptor, Angiotensin, Type 2 ; blood

OBJECTIVETo analyze the expression of angiotensin II (ANG II) receptor and apoptosis in myocardium in rats of endotoxemia.

METHODSModel of endotoxemia was induced by intraperitoneal injection with lipopolysaccharide (LPS) 10 mg/kg in male Wistar rats and saline was injected into control group. The rats were killed at 2 h or 6 h after saline (control) or LPS . Expression of the correlation factors related to apoptosis of Bcl-2, Bax, AT1 and AT2 receptor in myocardial tissue were detected with immunohistochemistry (IHC), and changes of myocardial cells apoptosis was detected by the method of TUNEL. The gene expression of AT1 and AT2 receptor was examined by RT-PCR. The pathological changes of myocardial tissue were observed by electron microscope.

RESULTSCompared with control group , the expression of AT1 and AT2 receptor were significantly decreased, especially in 6 h group; and the expression of Bcl-2 and Bax were decreased, the ratio of Bcl-2/Bax had the downtrend as well as the apoptosis of myocardial cells.

CONCLUSIONInterfered by LPS, the down regulation of AT1 and AT2 receptor expression has the negative relation with apoptosis of myocardial cells, this result indicated that down regulation of AT1 and AT2 receptor expression maybe related to cardiac functional impairment, which maybe help us to find a new protective path to prevent myocardial damage induced by systemic inflammatory.

Animals ; Apoptosis ; Endotoxemia ; metabolism ; Male ; Myocytes, Cardiac ; cytology ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; metabolism ; Receptor, Angiotensin, Type 2 ; metabolism

OBJECTIVEThe present study was undertaken to observe the expression of angiotensin II (Ang II) type 1 (AT1) and type 2 (AT2) receptors in human hypertrophic scars, and explore their role in the proliferation of fibroblasts in human hypertrophic scars.

METHODSThe expression of both ATL and AT2 receptors in fibroblasts of hypertrophic scars was detected with immunohistochemical staining. Radioligand receptor binding assay and RT-PCR were used to determined expression level of AT1 and AT2 receptors in cultured fibroblasts derived from hypertrophic scars. DNA synthesis was examined in cultured fibroblasts of hypertrophic scars by measuring [3H]-TdR incorporation into fibroblasts.

RESULTSPositive staining signals of both AT1 and AT2 receptors were found in fibroblasts of hypertrophic scars. Expression level of AT1 and AT2 receptors were (10.69 +/- 2.15) fmol/10(6) cells, (4.9 +/- 1.05) fmol/10(6) cells respectively in cultured fibroblasts derived from hypertrophic scars. RT-PCR showed the similar results. In cultured fibroblasts, Ang II stimulation significantly increased DNA synthesis (P < 0.05 vs negative control), which was inhibited by valsartan, an AT1 receptor blocker, but augmented by PD123319, an AT2 receptor antagonist. Valsartan or PD123319 alone did not influence the proliferation of fibroblasts derived from hypertrophic scars.

CONCLUSIONSBoth AT1 and AT2 receptors were expressed in the fibroblasts of hypertrophic scars, and Ang II regulates DNA synthesis in hypertrophic scar fibroblasts through a negative cross-talk between AT1 and AT2 receptors, which might contribute, at least partly to formation and maturation of human hypertrophic scars. The present study provides new insight into pathogenesis of hypertrophic scars.

Cell Proliferation ; Cells, Cultured ; Cicatrix, Hypertrophic ; metabolism ; pathology ; DNA ; biosynthesis ; Fibroblasts ; metabolism ; physiology ; Humans ; Receptor, Angiotensin, Type 1 ; metabolism ; Receptor, Angiotensin, Type 2 ; metabolism ; Signal Transduction

OBJECTIVETo investigate the relationship between dyslipidemia and the polymorphism of angiotensin II type 1 receptor (AT(1)R) gene A1166C in hypertensive Kazakans of Xinjiang area.

METHODSPolymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) methods were used to detect the A1166C polymorphism of AT(1)R gene of 296 hypertensive and 198 normotensive Kazakans. Biochemical parameters were measured by autochemical emalyzer.

RESULTS(1) The TC and LDL-C levels are significantly higher in hypertension group than those in normotensive controls [TC: (4.91 +/- 1.19) mmol/L vs. (4.43 +/- 1.20) mmol/L; LDL-C: (3.36 +/- 1.01) mmol/L vs. (2.94 +/- 1.30) mmol/L, P < 0.001). (2) In hypertension group, TC and LDL-C are related to A1166C polymorphism of AT(1)R gene and TC and LDL-C of AC carriers are significantly higher than AA carriers (P < 0.05).

CONCLUSIONThe dyslipidemia is related to A1166C polymorphism of AT(1)R gene in hypertensive Kazakans.

Gene Frequency ; Genotype ; Humans ; Hypertension ; Polymorphism, Genetic ; Receptor, Angiotensin, Type 1 ; genetics