Aldosterone/Mineralocorticoid Receptor Downstream Targets as Novel Therapeutic Targets to Prevent Cardiovascular Remodeling

The incidence of heart failure (HF) is increasing because of aging of the population. Despite optimal therapy, patients with HF experience disease progression associated with high mortality rates. HF is still the first cause of hospital admission in subjects aged >65 years. The obvious solution for HF epidemics is to prevent new-onset HF with therapies directed specifically to mechanistic targets that are involved in the transition to HF. The mineralocorticoid receptor (MR) and its natural ligand, the hormone aldosterone (Aldo), play important roles during cardiac and arterial remodeling, but the underlying effects are still not understood. MR antagonists are highly recommended for treatment of systolic symptomatic HF. However, adverse effects limit their use in clinical practice. Galectin-3 (Gal-3), neutrophil gelatinase-associated lipocalin (NGAL), and cardiotrophin-1 (CT-1) have been identified as highly focused targets controlling downstream key MR-mediated HF mechanisms. Therefore, interfering with mechanistic pathways involved in downstream MR activation may provide therapeutic alternatives to MR antagonists. The aim of this review is to focus on the role of the MR biotargets in cardiovascular remodeling

Potential Benefit of Mineralocorticoid Receptor Antagonists in Kidney Diseases

Since the last two decades, a major paradigm shift occurred in our understanding of the physiological and pathophysiological roles of the mineralocorticoid receptor (MR). Expression of the MR in cells/tissues not involved in sodium/potassium balance and extracellular volume homeostasis, i.e., the primary role of the aldosterone/MR complex, paved the way to the discovery of unsuspected implications of MR in a variety of cellular processes and pathological consequences. It also opens the possibility for quick translation to the bedside using available MR antagonists (MRAs) such as spironolactone, canrenone, or eplerenone or using the more recently developed various nonsteroidal MRAs that are not yet marketed. Landmark clinical trials like RALES, EPHESUS, or EMPHASIS well established that MRAs provide great benefits in patients with heart failure and spironolactone or eplerenone have been recommended in these patients. The deep understanding provided by preclinical studies in various domains stimulated the possibility to extend the use of MRAs to new fields, including renal diseases even if MRAs are currently contraindicated or used with great caution in patients with renal function impairment due to the higher risk of hyperkalemia associated with MRA therapy in this at-risk population. The present review presents preclinical data supporting potential indications in renal diseases

0307 Role of vascular mineralocorticoid receptor in renal injury induced by ischemia/reperfusion

IntroductionAcute kidney injury (AKI) is defined as an abrupt decrease (48h) in kidney function. One of the main causes of AKI is ischemia/reperfusion (I/R). AKI is related with high mortality, chronic kidney disease development and cardiac alterations like heart failure and arrhythmias. Mineralocorticoid receptor (MR) antagonism with spironolactone (Sp) prevents tubular injury and renal dysfunction induced by I/R in the rat. Although there is information supporting a role for aldosterone and MR in kidney injury, it remains unexplored the specific role of the MR expressed in the vasculature in mediating the deleterious effects of aldosterone during renal I/R.ObjectiveTo study the effect of inducing I/R in mice lacking the MR specifically in the endothelial cells or in the vascular smooth muscle cells.MethodsTo test if Sp is also able to prevent renal injury induced by I/R in the mice with the C57BL/6 background (same as MR KO mice) we included three groups of mice: 1) Sham, 2) I/R 20 min and 3) I/R 20 min + Sp pre-treatment. We analyzed the presence of renal dysfunction and inflammatory cytokines. In the MR KO mice, we will analyze the effect of MR deficiency after renal I/R in an acute phase (24h) and in chronic kidney disease development (after 4 weeks). In the acute studies the mechanisms that will be explored include: polarization of macrophages, endothelial injury and oxidative stress. In the chronic studies we will test if the wild type or MR knockout mice develop CKD as a consequence of renal I/R.ResultsMice underwent renal I/R developed injury characterized by increased serum creatinine and urea levels, urinary Hsp72 and elevation in the mRNA of TNF-alpha and MCP-1 pro-inflammatory cytokines. These alterations were prevented by the Sp pre-treatment.ConclusionThe protective effect of Sp against renal I/R that was previously reported in the rat is also observed in the C57BL/6 mice and supports the study of the MR KO mice in the renal I/R setting

11β-HSD2 SUMOylation Modulates Cortisol-induced Mineralocorticoid Receptor Nuclear Translocation Independently of Effects on Transactivation

The enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) has an essential role in aldosterone target tissues, conferring aldosterone selectivity for the mineralocorticoid receptor (MR) by converting 11β-hydroxyglucocorticoids to inactive 11-ketosteroids. Congenital deficiency of 11β-HSD2 causes a form of salt-sensitive hypertension known as the syndrome of apparent mineralocorticoid excess. The disease phenotype, which ranges from mild to severe, correlates well with reduction in enzyme activity. Furthermore, polymorphisms in the 11β-HSD2 coding gene (HSD11B2) have been linked to high blood pressure and salt sensitivity, major cardiovascular risk factors. 11β-HSD2 expression is controlled by different factors such as cytokines, sex steroids, or vasopressin, but posttranslational modulation of its activity has not been explored. Analysis of 11β-HSD2 sequence revealed a consensus site for conjugation of small ubiquitin-related modifier (SUMO) peptide, a major posttranslational regulatory event in several cellular processes. Our results demonstrate that 11β-HSD2 is SUMOylated at lysine 266. Non-SUMOylatable mutant K266R showed slightly higher substrate affinity and decreased Vmax, but no effects on protein stability or subcellular localization. Despite mild changes in enzyme activity, mutant K266R was unable to prevent cortisol-dependent MR nuclear translocation. The same effect was achieved by coexpression of wild-type 11β-HSD2 with sentrin-specific protease 1, a protease that catalyzes SUMO deconjugation. In the presence of 11β-HSD2-K266R, increased nuclear MR localization did not correlate with increased response to cortisol or increased recruitment of transcriptional coregulators. Taken together, our data suggests that SUMOylation of 11β-HSD2 at residue K266 modulates cortisol-mediated MR nuclear translocation independently of effects on transactivation

Pioglitazone modulates the vascular contractility in hypertension by interference with ET-1 pathway

Endothelin-1 (ET-1) is an important modulator of the vascular tone and a proinflammatory molecule that contributes to the vascular damage observed in hypertension. Peroxisome-proliferator activated receptors-γ (PPARγ) agonists show cardioprotective properties by decreasing inflammatory molecules such as COX-2 and reactive oxygen species (ROS), among others. We investigated the possible modulatory effect of PPARγ activation on the vascular effects of ET-1 in hypertension. In spontaneously hypertensive rats (SHR), but not in normotensive rats, ET-1 enhanced phenylephrineinduced contraction through ETA by a mechanism dependent on activation of TP receptors by COX-2- derived prostacyclin and reduction in NO bioavailability due to enhanced ROS production. In SHR, the PPARγ agonist pioglitazone (2.5 mg/Kg·day, 28 days) reduced the increased ETA levels and increased those of ETB. After pioglitazone treatment of SHR, ET-1 through ETB decreased ROS levels that resulted in increased NO bioavailability and diminished phenylephrine contraction. In vascular smooth muscle cells from SHR, ET-1 increased ROS production through AP-1 and NFκB activation, leading to enhanced COX-2 expression. These effects were blocked by pioglitazone. In summary, in hypertension, pioglitazone shifts the vascular ETA/ETB ratio, reduces ROS/COX-2 activation and increases NO availability; these changes explain the effect of ET-1 decreasing phenylephrine-induced contractionThis work was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (SAF2015-69294-R and SAF2016-80305-P), Instituto de Salud Carlos III (CIBER de Enfermedades Cardiovasculares, CB16.11.00286), Comunidad de Madrid (B2017/BMD-3676) and Fondo Europeo de Desarrollo Regional (FEDER) a way to build Europ

Sex-dependent expression of neutrophil gelatinase-associated lipocalin in aortic stenosis

Background: Accumulating evidence suggest the existence of sex-related differences in the pathogenesis of aortic stenosis (AS) with inflammation, oxidative stress, fibrosis and calcification being over-represented in men. Neutrophil gelatinase-associated lipocalin (NGAL) is expressed in a myriad of tissues and cell types, and it is associated with acute and chronic pathological processes comprising inflammation, fibrosis or calcification. Sex-dependent signatures have been evidenced for NGAL which expression has been associated predominantly in males to metabolic and cardiovascular disorders. We aimed to analyse sex-related differences of NGAL in AS and its role in the inflammatory and fibrocalcific progression of AS. Methods and results: 220 (60.45% men) patients with severe AS elective for surgical aortic valve (AV) replacement were recruited. Immunohistochemistry revealed higher expression of NGAL in calcific areas of AVs and that was validated by qPCR in in 65 (60% men) donors. Valve interstitial cells (VICs) were a source of NGAL in these samples. Proteome profiler analyses evidenced higher expression of NGAL in men compared to women, and that was further validated by ELISA. NGAL expression in the AV was correlated with inflammation, oxidative stress, and osteogenic markers, as well as calcium score. The expression of NGAL, both intracellular and secreted (sNGAL), was significantly deregulated only in calcifying male-derived VICs. Depletion of intracellular NGAL in calcifying male-derived VICs was associated with pro-inflammatory profiles, dysbalanced matrix remodelling and pro-osteogenic profiles. Conversely, exogenous NGAL mediated inflammatory and dysbalanced matrix remodelling in calcifying VICs, and all that was prevented by the pharmacological blockade of NGAL. Conclusions: Owing to the over-expression of NGAL, the AV from men may be endowed with higher expression of inflammatory, oxidative stress, matrix remodelling and osteogenic markers supporting the progression of calcific AS phenotypes. The expression of NGAL in the VIC emerges as a potential therapeutic checkpoint, with its effects being potentially reverted by the pharmacological blockade of extracellular NGAL.This research was funded by Miguel Servet contract CP13/00221 from Instituto de Salud Carlos III-FEDER, Fondo de Investigaciones Sanitarias [PI18/01875; PI21/00280]. M.G. is supported by a Miguel Servet Foundation PhD studentship, E.M.-N is supported by a Margarita Salas postdoctoral fellowship (ULL-MS-P14), L.M. is supported by a PFIS (FI19/00302) PhD studentship, E.J. (CD19/00251) is supported by a Sara Borrell postdoctoral fellowship

Lipocalin 2 as a potential systemic biomarker for central serous chorioretinopathy

No systemic biomarker of Central Serous Chorioretinopathy (CSCR) has been identified. Lipocalin 2 (LCN2 or NGAL), alone or complexed with MMP-9 (NGAL/MMP-9), is increased in several retinal disorders. Serum levels of LCN2 and NGAL/MMP-9 were measured in CSCR patients (n = 147) with chronic (n = 76) or acute/recurrent disease (n = 71) and in age- and sex-matched

The Epidermal Growth Factor Receptor Is Involved in Angiotensin II But Not Aldosterone/Salt-Induced Cardiac Remodelling

Experimental and clinical studies have shown that aldosterone/mineralocorticoid receptor (MR) activation has deleterious effects in the cardiovascular system; however, the signalling pathways involved in the pathophysiological effects of aldosterone/MR in vivo are not fully understood. Several in vitro studies suggest that Epidermal Growth Factor Receptor (EGFR) plays a role in the cardiovascular effects of aldosterone. This hypothesis remains to be demonstrated in vivo. To investigate this question, we analyzed the molecular and functional consequences of aldosterone exposure in a transgenic mouse model with constitutive cardiomyocyte-specific overexpression of a mutant EGFR acting as a dominant negative protein (DN-EGFR). As previously reported, Angiotensin II-mediated cardiac remodelling was prevented in DN-EGFR mice. However, when chronic MR activation was induced by aldosterone-salt-uninephrectomy, cardiac hypertrophy was similar between control littermates and DN-EGFR. In the same way, mRNA expression of markers of cardiac remodelling such as ANF, BNF or β-Myosin Heavy Chain as well as Collagen 1a and 3a was similarly induced in DN-EGFR mice and their CT littermates. Our findings confirm the role of EGFR in AngII mediated cardiac hypertrophy, and highlight that EGFR is not involved in vivo in the damaging effects of aldosterone on cardiac function and remodelling

Cardiomyopathy and Response to Enzyme Replacement Therapy in a Male Mouse Model for Fabry Disease

Fabry disease is an X-linked disorder of glycosphingolipid metabolism that results in progressive accumulation of neutral glycosphingolipids, (predominately globotriaosylceramide; GL-3) in lysosomes, as well as other cellular compartments and the extracellular space. Our aim was to characterize the cardiac phenotype of male knock-out mice that are deficient in alpha-galactosidase A activity, as a model for Fabry disease and test the efficacy of Enzyme Replacement Therapy with agalsidase-beta. Male mice (3–4 months of age) were characterized with awake blood pressure and heart rate measurements, cardiac echocardiography and electrocardiography measurements under light anesthesia, histological studies and molecular studies with real-time polymerase chain reaction. The Fabry knock-out mouse has bradycardia and lower blood pressure than control wild type (CB7BL/6J) mice. In Fabry knock-out mice, the cardiomyopathy associated mild hypertrophy at echography with normal systolic LV function and mild diastolic dysfunction. Premature atrial contractions were more frequent in without conduction defect. Heart weight normalized to tibial length was increased in Fabry knock-out mice. Ascending aorta dilatation was observed. Molecular studies were consistent with early stages of cardiac remodeling. A single dose of agalsidase-beta (3 mg/kg) did not affect the LV hypertrophy, function or heart rate, but did improve the mRNA signals of early cardiac remodeling. In conclusion, the alpha-galactosidase A deficient mice at 3 to 4 months of age have cardiac and vascular alterations similar to that described in early clinical stage of Fabry disease in children and adolescents. Enzyme replacement therapy affects cardiac molecular remodeling after a single dose

Aldosterone-Mineralocorticoid Receptor - Cell Biology to Translational Medicine

This book is an open access dissemination of the EU COST Action ADMIRE in Aldosterone/Mineralocorticoid Receptor (MR) physiology and pathophysiology. Aldosterone is the major hormone regulating blood pressure. Alterations in blood levels of aldosterone and genetic mutations in the MR receptor are major causes of hypertension and comorbidities. Many of the drugs in clinical use, and in development for treating hypertension, target aldosterone and MR actions in the kidney and cardiovascular system. The ADMIRE book assembles review chapters from 16 European ADMIRE laboratories providing the latest insights into mechanisms of aldosterone synthesis/secretion, aldosterone/MR physiology and signaling, and the pathophysiological roles of aldosterone/MR activation