To delineate the molecular mechanism underlying the inverse agonist activity of olmesartan, a potent angiotensin II type 1 (AT 1 ) receptor antagonist, we performed binding affinity studies and an inositol phosphate production assay. 257 was found to be important for the interaction with olmesartan but not for the inverse agonist activity. Based on these results, we constructed a model for the interaction between olmesartan and the AT 1 receptor. Although the activation of G protein-coupled receptors is initiated by anti-clockwise rotation of transmembrane (TM) III and TM VI followed by changes in the conformation of the receptor, in this model, cooperative interactions between the hydroxyl group and Tyr 113 in TM III and between the carboxyl group and His 256 in TM VI were essential for the potent inverse agonist activity of olmesartan. We speculate that the specific interaction of olmesartan with these two TMs is essential for stabilizing the AT 1 receptor in an inactive conformation. A better understanding of the molecular mechanisms of the inverse agonism could be useful for the development of new G proteincoupled receptor antagonists with inverse agonist activity.Angiotensin II (Ang II) 3 receptor antagonists (ARBs) are highly selective for the Ang II type 1 (AT 1 ) receptor, which is a member of the G protein-coupled receptor (GPCR) superfamily, and block the diverse effects of Ang II. In addition to their blood pressure-lowering effects in hypertensive patients, ARBs have been shown to promote regression of left ventricular hypertrophy and decrease cardiovascular morbidity and mortality in patients with heart failure or hypertensive diabetic nephropathy with proteinuria (1). Many ARBs are available for clinical use. Because not all ARBs have the same effects, some benefits conferred by ARBs may not be class effects (2). This notion represents an exciting new area in ARB-based therapy, which holds the promise of reducing the incidence of cardiovascular disease.Inverse agonists, such as the opioid receptor ligand ICI174864 (3), block agonist-independent signal transduction by GPCRs. Many clinically important medications have been shown to behave as inverse agonists when tested against either wild-type (WT) or mutated GPCRs; e.g. olanzapine in the 5-hydroxytryptamine 2C receptors (4) and metoprolol in the ␤-adrenoreceptor (5). Spontaneous receptor mutations leading to constitutive activity have been implicated in some human diseases (6, 7). However, such spontaneous mutations have not been reported for the AT 1 receptor, and the WT AT 1 receptor shows slight constitutive activity (2). A recent study demonstrates that the WT AT 1 receptor is activated by mechanical stretching of cultured rat myocytes without the involvement of Ang II, and this was suppressed by an inverse agonist (8). The same study also demonstrates that cardiac hypertrophy induced by constricting the transverse aorta in angiotensinogen knock-out mice was attenuated by an inverse agonist, suggesting that the WT AT 1 receptor is activated ind...

With conventional lifestyle modification programs, it can be difficult for hypertensive individuals to modify their lifestyles and maintain the changes. We assessed whether a multicomponent program (patient-centered assessment and counseling for exercise plus nutrition [PACE Japan]) based on behavior theory and social cognitive theory would be effective for treating patients with essential hypertension. We examined 57 outpatients aged 62 10 years with essential hypertension irrespective of antihypertensive drug treatment.Participants were randomly divided into two groups: 1) a PACE Japan follow-up group (n 18), who were given an action-plan sheet and systemic health counseling by a physician and counselor every 4 weeks for 24 weeks, and 2) a PACE Japan-only group (n 20), who were given an action-plan sheet but did not receive counseling. An age-and sex-matched control group (n 19) was also selected. The decrease in systolic blood pressure (SBP) ( SBP SBP at 24 weeks minus that at 0 weeks) in the PACE Japan follow-up group was significantly greater than that in the control group. In addition, the percentage of Fat (%Fat) and urinary sodium extraction (U-Na) in the PACE Japan follow-up group were significantly greater than those in the control group. With regard to changes in total energy expenditure, exercise energy expenditure and total energy intake between 0 weeks and 24 weeks, significant improvements were observed for the PACE Japan follow-up group. U-Na was determined to significantly predict SBP as assessed by stepwise selection. In addition, the partial correlation coefficient of SBP with U-Na was 0.361 ( p 0.

hemokines facilitate leukocyte migration and positioning, as well as other processes such as cell activation and differentiation. 1 They and their receptors constitute a large set of proteins and 2 subfamilies, CXC and CC chemokines and their receptors, have been identified. 2 There is increasing evidence from both clinical and animal studies that leukocytes play a central role in restenosis after balloon angioplasty and stent implantation in patients with coronary artery disease (CAD). Plasma concentrations of monocyte chemoattractant protein-1 (MCP-1), which is a ligand for CCR2, are elevated in patients with restenosis after coronary angioplasty 3 and Horvath et al reported that blockade of CCR2 effectively reduced neointimal hyperplasia after stenting in an animal model. 4 Although there is no clear evidence to show that CXC chemokines are associated with coronary stenosis in patients with CAD, recent studies have shown that they are involved in graft rejection and ischemia -perfusion injury. The interferon-inducible protein 10 (IP10) is a chemoattractant for human monocytes and lymphocytes and promotes T cell adhesion to endothelial cells. 5 The presence of CXCR3 + T cells and the CXCR3 ligand IP10 in 169 sequential human endomyocardial biopsies strongly associ- Circulation Journal Vol.67, October 2003ate the chemokine with acute allograft rejection. 6 Interestingly, Horiuchi et al found only weak expression of CXCR3 on cells in the outer layer of the neointima and adventitia and found the strongest staining in the innermost layer of the neointima in rat models of transplant vasculopathy. 7 Because neointimal hyperplasia is seen after coronary angioplasty, CXC chemokines may be a new target for preventing coronary stenosis.In the present study, we hypothesized that coronary stenosis is associated with a significant expression of leukocyte IP10 -CXCR3, although there is no clear evidence that blockade of the IP10 -CXCR3 interaction has beneficial effects on coronary stenosis in patients with CAD. Accordingly, in the present study, we investigated the levels of expression of CC and CXC chemokines and their receptors, including the IP10 -CXCR3 interaction, in patients with de novo stenosis or restenosis. Methods Study PopulationThe subject group comprised 55 patients with CAD who underwent percutaneous transluminal coronary angioplasty (PTCA) including stent implantation and 20 patients without significant coronary stenosis (defined as >50% luminal narrowing) based on the results of coronary angiography during the same period as a control group (C group, n=20). The patients with CAD were divided into 3 groups: 20 with de novo stenosis (D group), 15 with restenosis (R group) and 20 without restenosis (N group) after PTCA.Exclusion criteria were acute myocardial infarction and In rat models of transplant vasculopathy, the strongest staining of CXCR3 is observed in the innermost layer of the neointima and because neointimal hyperplasia is seen after coronary angioplasty, the CXC chemokines may be targets for prev...

Objective It is unclear whether the reduction of coronary restenosis by statins is due to a decrease in low-

A recent clinical study indicated that an angiotensin II (Ang II) type 1 (AT) receptor-neprilysin inhibitor (ARNi) designated LCZ696 (sacubitril/valsartan, as combined sodium complex) was superior to enalapril at reducing the risks of death and hospitalization due to heart failure. Therefore, we investigated the possible mechanisms of the beneficial effect of LCZ696, in which the inhibition of neprilysin enhances atrial natriuretic peptide (NP) or brain NP (ANP or BNP)-evoked signals that can block Ang II/AT receptor-induced aldosterone (Ald) synthesis in human adrenocortical cells. The binding affinity of valsartan+LBQ657 (active moiety of sacubitril) to the AT receptor was greater than that of valsartan alone in an AT receptor-expressing human embryonic kidney cell-based assay. There was no difference in the dissociation from the AT receptor between valsartan+LBQ657 and valsartan alone. In Ang II-sensitized human adrenocortical cells, ANP or BNP alone, but not LBQ657 or valsartan alone, significantly decreased Ald synthesis. The level of suppression of Ald synthesis by ANP or BNP with LBQ657 was greater than that by ANP or BNP without LBQ657. The suppression of ANP was blocked by inhibitors of regulator of G-protein signaling proteins and cyclic GMP-dependent protein kinase. The inhibition of neprilysin did not change the mRNA levels of the AT receptor, ANP receptor A, regulator of G-protein signaling protein, renin or 3β-hydroxysteroid dehydrogenases. In conclusion, the inhibition of neprilysin by LBQ657 enhances the NP-evoked signals that can block Ang II/AT receptor-induced Ald synthesis in human adrenocortical cells.