Aldosterone Synthase Inhibitors Research Articles

Overcoming Undesirable CYP1A2 Inhibition of Pyridylnaphthalene-Type Aldosterone Synthase Inhibitors: Influence of Heteroaryl Derivatization on Potency and Selectivity

Recently, we reported on the development of potent and selective inhibitors of aldosterone synthase (CYP11B2) for the treatment of congestive heart failure and myocardial fibrosis. A major drawback of these nonsteroidal compounds was a strong inhibition of the hepatic drug-metabolizing enzyme CYP1A2. In the present study, we examined the influence of substituents in the heterocycle of lead structures with a naphthalene molecular scaffold to overcome this unwanted side effect. With respect to CYP11B2 inhibition, some substituents induced a dramatic increase in inhibitory potency. The methoxyalkyl derivatives 22 and 26 are the most potent CYP11B2 inhibitors up to now (IC50 = 0.2 nM). Most compounds also clearly discriminated between CYP11B2 and CYP11B1, and the CYP1A2 potency significantly decreased in some cases (e.g., isoquinoline derivative 30 displayed only 6% CYP1A2 inhibition at 2 microM concentration). Furthermore, isoquinoline derivative 28 proved to be capable of passing the gastrointestinal tract and reached the general circulation after peroral administration to male Wistar rats.

Aldosterone synthase inhibition improves cardiovascular function and structure in rats with heart failure: a comparison with spironolactone

Inhibition of aldosterone synthase, the key enzyme in aldosterone formation, could be an alternative strategy for mineralocorticoid-receptor antagonists in congestive heart failure (CHF), but its effect in CHF is unknown. We compared, in rats with CHF, the effects of a 7 day and a 12 week treatment with the aldosterone synthase inhibitor FAD286 (4 mg kg(-1) day(-1)) with those induced by spironolactone (80 mg kg(-1) day(-1)). FAD286/spironolactone increased cardiac output without modifying arterial pressure. Long-term FAD286 and spironolactone reduced left ventricular (LV) end-diastolic pressure, LV relaxation constant, and LV dilatation, and these effects were more marked with FAD286, whereas both drugs reduced LV hypertrophy and collagen accumulation to the same extent. Long-term FAD286/spironolactone prevented CHF-related enhancement in LV ACE and reduction in LV ACE-2, but only FAD286 prevented the reduction in LV AT(2) receptors. FAD286, but not long-term spironolactone, reduced the CHF-related enhancements in LV reactive oxygen species, reduced-oxidized glutathione ratio, and aortic nicotinamide adenine dinucleotide phosphate oxidase activity. FAD286 normalized the CHF-induced impairment of endothelium-dependent vasodilatation. In experimental CHF, FAD286 and spironolactone improve LV haemodynamics, remodelling, and function, but only FAD286 persistently normalizes LV 'redox status'. These results suggest that aldosterone synthase inhibition is a potential therapeutic strategy for the treatment of CHF.

Local renal aldosterone production induces inflammation and matrix formation in kidneys of diabetic rats

Recently, we reported the presence of a local renal aldosterone production. In the present study, we tested the hypothesis that local aldosterone production in the kidney contributes to renal inflammation, matrix formation and albuminuria associated with diabetes. We evaluated changes in renal aldosterone content (RAC), aldosterone synthase expression, nuclear factor kappaB (NFkappaB), tumour necrosis factor alpha (TNFalpha), interleukin-6 (IL-6), transforming growth factor beta (TGFbeta), glomerular fibronectin, collagen type IV and urinary albumin extraction (UAE) in response to the aldosterone synthase inhibitor FAD286. Studies were conducted in adrenalectomized, normoglycaemic (control) or diabetic rats for 14 weeks. The FAD286 was administered during the last 10 weeks of the study. Plasma aldosterone levels were not detectable in any of the study groups. Compared with control rats, diabetic rats had higher levels of RAC by 488% (P < 0.01), NFkappaB by 293% (P < 0.01), TNFalpha by 356% (P < 0.01), IL-6 by 378% (P < 0.01), TGFbeta by 337% (P < 0.01) and UAE by 1122% (P < 0.01), and increased glomerular fibronectin and collagen type IV immunostaining. In diabetic rats, FAD286 reduced RAC (P < 0.01), UAE (P < 0.05), NFkappaB mRNA, TNFalpha mRNA, IL-6 mRNA and TGFbeta mRNA by 51, 41, 41 and 52% and also their proteins and decreased glomerular fibronectin and collagen type IV immunostaining. In conclusion, diabetes increases local aldosterone production in the kidney, which contributes to development of renal inflammation, matrix formation and albuminuria. Inhibition of aldosterone production in the kidney could be helpful in management of diabetic nephropathy.

Aldosterone and the autocrine modulation of potassium currents and oxidative stress in the diabetic rat heart

Aldosterone plays a major role in cardiac pathology. This study was designed to investigate the role of cardiac aldosterone in modulating K(+) currents and oxidative stress in the streptozotocin-induced diabetic rat heart. Transient and sustained K(+) currents were measured in ventricular myocytes by voltage clamp. Plasma and cellular aldosterone were measured by ELISA. Fluorescent dihydroethidium (DHE) was used to assess superoxide ions as markers of oxidative stress. The mineralocorticoid antagonist spironolactone (1 microM, 5-9 h) significantly augmented both K(+) currents in diabetic males, with a concomitant shortening of the action potential but had no effect in myocytes from control males or from diabetic females. Effects of spironolactone were restored in ovariectomized diabetic females and abolished in orchidectomized diabetic males. The aldosterone synthase inhibitor FAD286 (1 microM, 5-9 h) significantly augmented K(+) currents in cells from diabetic males, but not females. Spironolactone and FAD286 significantly reduced oxidative stress in cells from diabetic males. Plasma aldosterone content was elevated in diabetic males (relative to control), but not in females. Cellular aldosterone was also elevated, but not significantly. The elevation in aldosterone was only partly dependent on a concomitant increase in cellular angiotensin II. A gender-related, sex-hormone-dependent elevation in plasma and cardiac cell aldosterone contributed to oxidative stress and to attenuation of K(+) currents in diabetic male rats. Aldosterone may thus contribute to diabetes-associated cardiac arrhythmias. Aldosterone elevation was partly related to levels of angiotensin II, but residual, angiotensin II-independent, aldosterone maintains functional relevance.

Central infusion of aldosterone synthase inhibitor prevents sympathetic hyperactivity and hypertension by central Na+ in Wistar rats

In Wistar rats, increasing cerebrospinal fluid (CSF) Na+ concentration ([Na+]) by intracerebroventricular (ICV) infusion of hypertonic saline causes sympathetic hyperactivity and hypertension that can be prevented by blockade of brain mineralocorticoid receptors (MR). To assess the role of aldosterone produced locally in the brain in the activation of MR in the central nervous system (CNS), Wistar rats were infused ICV with artificial CSF (aCSF), Na+ -rich (800 mmol/l) aCSF, aCSF plus the aldosterone synthase inhibitor FAD286 (100 microg x kg(-1) x day(-1)), or Na+ -rich aCSF plus FAD286. After 2 wk of infusion, rats treated with Na+ -rich aCSF exhibited significant increases in aldosterone and corticosterone content in the hypothalamus but not in the hippocampus, as well as increases in resting blood pressure (BP) and sympathoexcitatory responses to air stress, and impairment of arterial baroreflex function. Concomitant ICV infusion of FAD286 prevented the Na+ -induced increase in hypothalamic aldosterone but not corticosterone and prevented most of the increases in resting BP and sympathoexcitatory and pressor responses to air stress and the baroreflex impairment. FAD286 had no effects in rats infused with ICV aCSF. In another set of rats, 24-h BP and heart rate were recorded via telemetry before and during a 14-day ICV infusion of Na+ -rich aCSF with or without FAD286. Na+ -rich aCSF without FAD286 caused sustained increases ( approximately 10 mmHg) in resting mean arterial pressure that were absent in the rats treated with FAD286. These data suggest that in Wistar rats, an increase in CSF [Na+] may increase the biosynthesis of corticosterone and aldosterone in the hypothalamus, and mainly aldosterone activates MR in the CNS leading to sympathetic hyperactivity and hypertension.

The aldosterone synthase inhibitor FAD286 reduces plasma aldosterone concentration (PAC) with a long duration of action in a rat model of subchronic hyperaldosteronism

FAD286 (FAD) is a prototypical aldosterone synthase (CYP11B2) inhibitor that represents an alternative therapy to mineralocorticoid receptor antagonism. We previously characterized the effects of single oral treatment with FAD in a rat model of acute hyperaldosteronism secondary to angiotensin II (ANG II) infusion. In order to assess the effect of subchronic FAD treatment, we extended these studies using multiple dosing. ANG II was infused (30 ng/kg/min iv) for 11 days in cannulated Sprague‐Dawley rats to elevate PAC to ~2–7 nM. After 1 day (“baseline”), FAD (1, 3, or 10 mg/kg) was administered once daily by oral gavage for 2 or 9 consecutive days. Blood samples were collected at baseline and each subsequent day at 3 (“peak”) or 24 hr (“trough”) after dosing. FAD dose‐dependently lowered peak and trough PAC and elevated peak plasma FAD concentrations (~7200 nM at 10 mg/kg). At the highest dose of FAD, peak‐trough excursions in PAC were negligible despite low‐nM trough FAD concentrations. After discontinuing FAD (10 mg/kg) in the 2‐day‐dosing model, PACs remained blunted for at least 2 more days despite undetectable FAD in plasma. There were no signs of an accumulative drug effect or development of tolerance over the 9 days of FAD treatment. The long duration of action combined with the short PK half‐life suggest that FAD is retained at the target enzyme (CYP11B2) within the adrenal cortical mitochondria.

Aldosterone: From biosynthesis to non-genomic action onto the proteome

An increased aldosterone concentration can lead to a progression of heart diseases and to myocardial fibrosis. These fatal processes can be prevented by e.g. inhibiting the mineralocorticoid receptor (MR), which is nowadays part of a commonly applied standard therapy. Moreover, selective inhibition of aldosterone synthase (CYP11B2) is a straightforward goal whereby CYP11B1, a key enzyme in glucocorticoid biosynthesis exhibiting a high structure identity with CYP11B2 should not be inhibited. Therefore, effective test systems have been developed and rather potent and selective CYP11B2 compounds like SIAS-1 have been identified by our group. In addition to finding new inhibitors, we investigated which proteins are directly influenced by aldosterone focussing on non-genomic effects. Schizosaccharomyces pombe was chosen as a model organism, since this yeast does not contain nuclear steroid receptors, but many genes and regulatory mechanisms that are close to those of mammals. Besides creating a reference map for this organism, protein spots affected by aldosterone as well as deoxycorticosterone (DOC) and corticosterone have been identified. In case of aldosterone, a regulatory effect of proteins that are connected with structural proteins, signal cascades, osmoregulation and calcium pathway as well as to general metabolism have been discovered. DOC causes overlapping but also different effects compared with aldosterone. As shown exemplarily for GAPDH, the aldosterone-mediated effects in S. pombe can also be verified in mammalian cells. These and further investigations contribute to a deeper understanding of so-called non-genomic aldosterone effects.

Why are mineralocorticoid receptor antagonists cardioprotective?

Two clinical trials, the Randomized ALdosterone Evaluation Study (RALES) and the EPlerenone HEart failure and SUrvival Study (EPHESUS), have recently shown that mineralocorticoid receptor (MR) antagonists reduce mortality in patients with heart failure on top of ACE inhibition. This effect could not be attributed solely to blockade of the renal MR-mediated effects on blood pressure, and it has therefore been proposed that aldosterone, the endogenous MR agonist, also acts extrarenally, in particular in the heart. Indeed, MR are present in cardiac tissue, and possibly aldosterone synthesis occurs in the heart. This review critically addresses the following questions: (1) is aldosterone synthesized at cardiac tissue sites, (2) what agonist stimulates cardiac MR normally, and (3) what effects are mediated by aldosterone/MR in the heart that could explain the beneficial effects of MR blockade in heart failure? Conclusions are that most, if not all, of cardiac aldosterone originates in the circulation (i.e., is of adrenal origin), and that glucocorticoids, in addition to aldosterone, may serve as the endogenous agonist of cardiac MR. MR-mediated effects in the heart include effects on endothelial function, cardiac fibrosis and hypertrophy, oxidative stress, cardiac inotropy, coronary flow, and arrhythmias. Some of these effects occur via or in synergy with angiotensin II, and involve a non-MR-mediated mechanism. This raises the possibility that aldosterone synthase inhibitors might exert beneficial effects on top of MR blockade.

Investigation of aldosterone-synthase inhibition in rats

In-vivo investigation of aldosterone-synthase inhibitors requires experimental models to characterize the biological effects of these compounds. Seven successive experiments were performed in groups of 2-month-old male spontaneously hypertensive rats. Urinary free aldosterone was the main end-point measured during two contrasted diets: low sodium-high potassium (LS), inducing high urinary aldosterone (839 pmol/24 h, 95% confidence interval 654-1077), and high sodium-normal potassium (HS), inducing low urinary aldosterone (38.1 pmol/24 h; 95% confidence interval, 32.4-44.9). FAD 286 A (10 and 30 mg/kg) decreased urinary free aldosterone by 53 and 87% on the LS diet, and 50 and 75% on the HS. Plasma renin concentration increased three-fold after a 4-week treatment of 30 mg/kg FAD 286 A on the LS diet and did not change on the HS. The combination of FAD 286 A (30 mg/kg) and spironolactone (30 mg/kg) on the LS diet induced a biological picture of severe hypoaldosteronism and was not tolerated, whereas the HS diet prevented these abnormalities. The combination of FAD 286 A (30 mg/kg) and furosemide (30 mg/kg) on the HS diet corrected the diuretic-induced hypokalemia (4.1 +/- 0.2 versus 3.7 +/- 2.2 mEq/l, P < 0.033). This experimental model will be useful to screen future aldosterone-synthase inhibitors and study their biological effects in various experimental conditions.

Can the dextroenantiomer of the aromatase inhibitor fadrozole be useful for clinical investigation of aldosterone-synthase inhibition?

The beneficial effects of spironolactone, eplerenone, amiloride and potassium in preventing cardiovascular damage in various experimental models of salt-induced hypertension can be dissociated from blood pressure effects, and have drawn attention to the direct genomic and non-genomic actions of aldosterone at the level of the vessels, the heart and the kidneys. Exposure to endogenous aldosterone could be decreased by direct and specific aldosterone-synthase inhibition. FAD 286A, the dextroenantiomer of the aromatase inhibitor fadrozole, might be a first candidate to investigate in humans, the physiological impact and therapeutic properties of aldosterone-synthase inhibition, especially in various forms of primary aldosteronism.

Synthesis and Evaluation of Heteroaryl-Substituted Dihydronaphthalenes and Indenes: Potent and Selective Inhibitors of Aldosterone Synthase (CYP11B2) for the Treatment of Congestive Heart Failure and Myocardial Fibrosis

In this study, the synthesis and biological evaluation of heteroaryl-substituted dihydronaphthalenes and indenes (1-16) is described. The compounds were tested for activity by use of human CYP11B2 expressed in fission yeast and V79 MZh cells and for selectivity by use of human CYP11B1, CYP17, and CYP19. The most active inhibitor was the 6-methoxydihydronaphthalene 4 (IC(50) = 2 nM), showing a K(i) value of 1.3 nM and a competitive type of inhibition. The 5-methoxyindene 3 was found to be the most selective CYP11B2 inhibitor (IC(50) = 4 nM; CYP11B1 IC(50) = 5684 nM), which also showed only marginal inhibition of human CYP3A4 and CYP2D6. Docking and molecular dynamics studies using our homology-modeled CYP11B2 structure were performed to understand some structure-activity relationships. Caco-2 cell experiments revealed highly cell-permeable compounds, and metabolic studies with 4 using rat liver microsomes showed sufficient stability.

Nongenomic Renal Effects of Aldosterone

There is increasing evidence for a dependency on aldosterone in the development of hypertension.1 How aldosterone influences the physiology that determines blood pressure or for that matter promotes the pathophysiology of high blood pressure turns out to be less than straightforward. There is the genomic pathway that begins with the binding of aldosterone to the classical mineralocorticoid receptor (MR) and ends with sodium reabsorption at the distal nephron. But aldosterone can convey nongenomic influences as well, actions that have received less attention, possibly in part because they seem counterintuitive to our genomic view of biology. Adding to the complexity of aldosterone’s actions is the fact that there are also nonepithelial (nondistal nephron) targets of aldosterone, such as the heart, the vasculature, the kidney, and other sites. In this issue of Hypertension , Schmidt et al2 describe a rapid (thus nongenomic) effect of administered aldosterone to increase resistance in renal vasculature (a nonepithelial target) in healthy human subjects. The findings follow on the heels of a rather large body of work on the genomic actions of aldosterone. Aldosterone’s nongenomic effects were first recognized more than a decade before an aldosterone-inducible gene was identified in the late 1990s.3 A nongenomic action characteristically occurs almost immediately, usually within several minutes,4 before sufficient time has elapsed for gene …

408 Cardiovascular effects and angiotensin system adaptation in experimental heart failure after aldosterone synthase inhibition

408 Cardiovascular effects and angiotensin system adaptation in experimental heart failure after aldosterone synthase inhibition

Development and evaluation of a pharmacophore model for inhibitors of aldosterone synthase (CYP11B2)

Recently, we proposed inhibition of aldosterone synthase (CYP11B2) as a novel strategy for the treatment of congestive heart failure and myocardial fibrosis and synthesized a large number of inhibitors. In this work, a pharmacophore model for CYP11B2 inhibitors was developed by superimposition of active and non-active compounds. This model was confirmed by the synthesis of two pyridyl substituted acenaphthene derivatives ( A, B). This new class of compounds as well as the pharmacophore could be helpful for the discovery of novel inhibitors.

Heteroaryl-Substituted Naphthalenes and Structurally Modified Derivatives: Selective Inhibitors of CYP11B2 for the Treatment of Congestive Heart Failure and Myocardial Fibrosis

Recently we proposed inhibition of aldosterone synthase (CYP11B2) as a novel strategy for the treatment of congestive heart failure and myocardial fibrosis. In this study the synthesis and biological evaluation of heteroaryl-substituted naphthalenes and quinolines (1-31) is described. Key step for the preparation of the compounds was a Suzuki cross-coupling. Activity of the compounds was determined in vitro using human CYP11B2 and selectivity was evaluated toward the human steroidogenic enzymes CYP11B1, CYP19, and CYP17. A large number of highly active and selective inhibitors of CYP11B2 was identified. The most active inhibitor was the 6-cyano compound 8 (IC50 = 3 nM) showing a competitive type of inhibition (K(i) value = 1.9 nM). The 6-ethoxy derivative 5 was found to be the most selective CYP11B2 inhibitor (IC50 = 12 nM; K(i) value = 8 nM; CYP11B1 IC50 = 5419 nM; selectivity factor = 451), showing no inhibition of human CYP3A4 (50 nM) and CYP2D6 (20 nM). Docking and molecular dynamics studies using our homology modeled CYP11B2 structure with selected compounds were performed. Caco-2 cell experiments revealed a large number of medium and highly permeable compounds and metabolic studies with 2 using rat liver microsomes showed sufficient stability.

Issue Highlights

HomeCirculationVol. 111, No. 23Issue Highlights Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIssue Highlights Originally published14 Jun 2005https://doi.org/10.1161/circ.111.23.3015Circulation. 2005;111:3015ALDOSTERONE SYNTHASE INHIBITOR AMELIORATES ANGIOTENSIN II–INDUCED ORGAN DAMAGE, by Fiebeler et al.Aldosterone has been shown to contribute to angiotensin II–induced end-organ damage, and clinical studies have confirmed the benefit of adding aldosterone antagonists to angiotensin-converting enzyme inhibitor agents to prevent adverse remodeling. Angiotensin II increases circulating levels of aldosterone levels as well as de novo tissue synthesis of aldosterone by stimulating aldosterone synthase (CYP11B2); however, it is unknown which source of aldosterone plays a greater role in tissue remodeling and damage. In these studies, Fiebeler et al examine this question by utilizing both FAD286, a novel CYP11B2 inhibitor, and adrenalectomy in transgenic rats overexpressing human renin and angiotensinogen genes. Using these models, they are able to isolate the source of aldosterone that modulates some of the adverse cardiac and renal effects associated with hyperaldosteronism. See p 3087.LONG-TERM RESPONSE TO CALCIUM CHANNEL BLOCKERS IN IDIOPATHIC PULMONARY ARTERIAL HYPERTENSION, by Sitbon et al.Characteristics of patients with idiopathic pulmonary arterial hypertension (IPAH) who benefit from long-term calcium channel blockers (CCBs) are unknown. Sitbon and colleagues performed acute pulmonary vasodilator testing with epoprostenol or nitric oxide during initial right heart catheterization in 557 IPAH patients. Acute responders were treated initially with oral CCB. Long-term CCB responders were defined as those being in functional class I or II after at least 1 year on CCB monotherapy. Among the 70 patients (12.6%) who displayed acute pulmonary vasoreactivity and received CCB therapy, 38 (6.7%) improved long term. Long-term CCB responders had less severe disease at baseline and displayed a more pronounced fall in mean pulmonary artery pressure during acute vasodilator testing. Of note, long-term CCB responders represented less than 10% of IPAH patients evaluated in a pulmonary vascular referral center. These data suggest that routine administration of CCB as first-line therapy in IPAH patients may be ill advised. See p 3105.APOLIPOPROTEIN E MIMETIC PEPTIDE DRAMATICALLY LOWERS PLASMA CHOLESTEROL AND RESTORES ENDOTHELIAL FUNCTION IN WATANABE HERITABLE HYPERLIPIDEMIC RABBITS, by Gupta et al.Elevated high-density lipoprotein (HDL) levels are associated with a reduction in the frequency of cardiovascular events. To develop new drugs for the treatment of atherosclerosis, investigators have been evaluating the therapeutic properties of HDL components in both animal models of vascular disease and patients with coronary atherosclerosis. However, some of these agents are structurally complex and difficult to produce. In this issue of Circulation, Gupta et al analyze the atheroprotective properties of a synthetic peptide containing the arginine-rich receptor-binding domain of ApoE fused to an amphipathic helical peptide that possesses ApoA-I–like properties. A single administration of the dual-domain peptide dramatically reduces plasma cholesterol levels and improves vascular reactivity in a dyslipidemic rabbit model. These improvements coincide with a reduction in markers of oxidative stress that are associated with vascular inflammation. These data suggest that this HDL-mimetic peptide could make ‘good‘ cholesterol better and have utility for the treatment of atherosclerosis. See p 3112.Visit http://www.circ.ahajournals.org:Cardiology Patient PageHow to Respond to an Implantable Cardioverter-Defibrillator Shock. See p e380.Images in Cardiovascular MedicineReversible Right Ventricular Hypertrophy Due to Cardiac Sarcoidosis. See p e383. Download figureDownload PowerPointThree-Dimensional Imaging in Rupture of Papillary Muscle After Acute Myocardial Infarction. See p e385.Angiosarcoma of the Pericardium: A Fatal Disease. See p e388.CorrespondenceSee p e390. Previous Back to top Next FiguresReferencesRelatedDetails June 14, 2005Vol 111, Issue 23 Advertisement Article InformationMetrics https://doi.org/10.1161/circ.111.23.3015 Originally publishedJune 14, 2005 PDF download Advertisement

Synthesis and Evaluation of (Pyridylmethylene)tetrahydronaphthalenes/-indanes and Structurally Modified Derivatives: Potent and Selective Inhibitors of Aldosterone Synthase

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionSynthesis and Evaluation of (Pyridylmethylene)tetrahydronaphthalenes/-indanes and Structurally Modified Derivatives: Potent and Selective Inhibitors of Aldosterone SynthaseSarah Ulmschneider, Ursula Müller-Vieira, Christian D. Klein, Iris Antes, Thomas Lengauer, and Rolf W. HartmannCite this: J. Med. Chem. 2005, 48, 13, 4489–4490Publication Date (Web):May 19, 2005Publication History Published online19 May 2005Published inissue 1 June 2005https://doi.org/10.1021/jm058022pCopyright © 2005 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views343Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (48 KB) Get e-Alerts Get e-Alerts

Angiotensin II and Aldosterone Regulate Gene Transcription Via Functional Mineralocortocoid Receptors in Human Coronary Artery Smooth Muscle Cells

Inhibition or blockade of the angiotensin-aldosterone system consistently decreases ischemic cardiovascular events in clinical trials. The steroid hormone aldosterone acts by binding to the mineralocorticoid receptor (MR), a ligand activated transcription factor that is a member of the nuclear hormone receptor superfamily. MR binds and is activated by aldosterone and cortisol with equal affinity, but MR activation by cortisol is diminished in tissues that express the cortisol-inactivating enzyme 11-beta-hydroxysteroid-dehydrogenase-2 (11betaHSD2). Although previous studies support that the vasculature is a target tissue of aldosterone, MR-mediated gene expression in vascular cells has not been demonstrated or systematically explored. We investigated whether functional MR and 11betaHSD2 are expressed in human blood vessels. Human coronary and aortic vascular smooth muscle cells (VSMCs) express mRNA and protein for both MR and 11betaHSD2. The endogenous VSMC MR mediates aldosterone-dependent gene expression, which is blocked by the competitive MR antagonist spironolactone. Inhibition of 11betaHSD2 in coronary artery VSMCs enhances gene transactivation by cortisol, supporting that the VSMC 11betaHSD2 is functional. Angiotensin II also activates MR-mediated gene transcription in coronary artery VSMCs. Angiotensin II activation of MR-mediated gene expression is inhibited by both the AT1 receptor blocker losartan and by spironolactone, but not by aldosterone synthase inhibition. Microarray and quantitative RT-PCR experiments show that aldosterone activates expression of endogenous human coronary VSMC genes, including several involved in vascular fibrosis, inflammation, and calcification. These data support a new MR-dependent mechanism by which aldosterone and angiotensin II influence ischemic cardiovascular events, and suggest that ACE inhibitors and MR antagonists may decrease clinical ischemic events by inhibiting MR-dependent gene expression in vascular cells.

Synthesis and Evaluation of (Pyridylmethylene)tetrahydronaphthalenes/-indanes and Structurally Modified Derivatives: Potent and Selective Inhibitors of Aldosterone Synthase

Elevated aldosterone levels are key effectors for the development and progression of congestive heart failure and myocardial fibrosis. Recently, we proposed inhibition of aldosterone synthase (CYP11B2) as an innovative strategy for the treatment of these diseases. In this study, the synthesis and biological evaluation of E- and Z-(pyridylmethylene)tetrahydronaphthalenes and -indanes (1a,b-38a) is described. The activity of the compounds was determined using human CYP11B2, and the selectivity was evaluated toward the human steroidogenic enzymes CYP11B1, CYP19, and CYP17. The biological results revealed a few rather selective inhibitors of CYP11B1, some compounds inhibiting both CYP11B1 and CYP11B2, and a large number of highly selective inhibitors of CYP11B2. The most active inhibitor was the 3-pyridyl compound 5a (IC(50) = 7 nM). The pyrimidyl-substituted derivative 28a was found to be the most selective CYP11B2 inhibitor (IC(50) = 27 nM) in this series, showing a 120-fold selectivity for CYP11B1 (IC(50) = 3179 nM). Molecular modeling, i.e., examination of the electronic and steric features of selected compounds and homology modeling and docking, was used to understand the structure-activity/-selectivity relationships.

Synthesis of Amidinohydrazones and Evaluation of Their Inhibitory Effect towards Aldosterone Synthase (CYP11B2) and the Formation of Selected Steroids

The synthesis and biological evaluation of a series of amidinohydrazones (3a-h, 6a-c, 8 and 9) as potential nonsteroidal inhibitors of aldosterone synthase (CYP11B2) are described. The compounds were tested in vitro using CYP11B2-expressing fission yeast; they showed only marginal inhibitory effect. Compound 6c was evaluated for its effect on the formation of aldosterone, cortisol, androstenedione, and DHEA in the adrenocortical tumor cell line NCI-H295R. It exhibited no significant effect on the production of these products.