Is there a new dawn for selective mineralocorticoid receptor antagonism?

GRK5 is an essential co-repressor of the cardiac mineralocorticoid receptor and is selectively induced by finerenone

BACKGROUND

In the heart, aldosterone (Aldo) binds the mineralocorticoid receptor (MR) to exert damaging, adverse remodeling-promoting effects. We recently showed that G protein-coupled receptor-kinase (GRK)-5 blocks the cardiac MR by directly phosphorylating it, thereby repressing its transcriptional activity. MR antagonist (MRA) drugs block the cardiac MR reducing morbidity and mortality of advanced human heart failure. Non-steroidal MRAs, such as finerenone, may provide better cardio-protection against Aldo than classic, steroidal MRAs, like spironolactone and eplerenone.

AIM

To investigate potential differences between finerenone and eplerenone at engaging GRK5-dependent cardiac MR phosphorylation and subsequent blockade.

METHODS

We used H9c2 cardiomyocytes, which endogenously express the MR and GRK5.

RESULTS

GRK5 phosphorylates the MR in H9c2 cardiomyocytes in response to finerenone but not to eplerenone. Unlike eplerenone, finerenone alone potently and efficiently suppresses cardiac MR transcriptional activity, thus displaying inverse agonism. GRK5 is necessary for finerenone’s inverse agonism, since GRK5 genetic deletion renders finerenone incapable of blocking cardiac MR transcriptional activity. Eplerenone alone does not fully suppress cardiac MR basal activity regardless of GRK5 expression levels. Finally, GRK5 is necessary for the anti-apoptotic, anti-oxidative, and anti-fibrotic effects of both finerenone and eplerenone against Aldo, as well as for the higher efficacy and potency of finerenone at blocking Aldo-induced apoptosis, oxidative stress, and fibrosis.

CONCLUSION

Finerenone, but not eplerenone, induces GRK5-dependent cardiac MR inhibition, which underlies, at least in part, its higher potency and efficacy, compared to eplerenone, as an MRA in the heart. GRK5 acts as a co-repressor of the cardiac MR and is essential for efficient MR antagonism in the myocardium

Dihydropyrimidinones Scaffold as a Promising Nucleus for Synthetic Profile and Various Therapeutic Targets: A Review

BACKGROUND

This review elaborates the updated synthetic and pharmacological approaches of a known group of dihydropyrimidinones/thiones from the multi-component reaction like Biginelli reaction, which was named Pietro Biginelli in 1891. This review consists of the reaction of an aromatic aldehyde, urea and ethyl acetoacetate leading to dihydropyrimidinone/thione. Currently, the scientific movement to develop economically viable green methods using compounds that are reusable, non-volatile, easily obtained, etc. Objective: This review covers the recent synthesis and pharmacological advancement of dihydropyrimidinones/ thiones moiety, along with covering the structure-activity relationship of the most potent compounds, which may prove to become better, more efficacious and safer agents. Thus, this review may help the researchers in drug designing and development of new Dihydropyrimidinones entities.

CONCLUSION

This review focuses on the wide application of dihydropyrimidinone/thione review reports the design, synthesis and pharmacological activities of nitrogen-sulphur containing dihydropyrimidinone moiety by using multi-component reaction. Dihydropyrimidinones (DHPM) pharmacophore is an important heterocyclic ring in medicinal chemistry. It is derived from multi-component reactions, "Biginelli reaction" and plays a critical role as anticancer, antioxidant, antimicrobial, anti-inflammatory, anti-HIV-1, antimalarial, anti-inflammatory, antihypertensive and anti-tubercular agents. Exhaustive research has led to its vast biological profile, with a wide range of therapeutic application.

Hyperkalemia and Acute Kidney Injury with Spironolactone Use Among Patients with Heart Failure

OBJECTIVE

To quantify the risk of hyperkalemia and acute kidney injury (AKI) when spironolactone use is added on to loop diuretic use among patients with heart failure, and to evaluate whether the risk is modified by level of kidney function.

METHODS

We identified 17,110 patients with heart failure treated with loop diuretics between January 1, 2004, and December 31, 2016 within the Geisinger Health System. We estimated the incidence of hyperkalemia and AKI associated with spironolactone initiation, and used target trial emulation methods to minimize confounding by indication.

RESULTS

During a mean follow-up of 134 mo, 3229 of 17,110 patients (18.9%) initiated spironolactone. Incidence rates of hyperkalemia and AKI in patients using spironolactone with a loop diuretic were 2.9 and 10.1 events per 1000 person-months, respectively. In propensity score-matched analyses, spironolactone initiation was associated with higher hyperkalemia and AKI risk compared with loop alone (hazard ratio, 1.69; 95% CI, 1.35 to 2.10; P<.001, and hazard ratio, 1.12; 95% CI, 1.00 to 1.26; P=.04, respectively). There were no differences in the relative risk of either outcome associated with spironolactone by level of kidney function.

CONCLUSION

The addition of spironolactone to loop diuretics in patients with heart failure was associated with higher risk of hyperkalemia and AKI; these risks must be weighed against the potential benefits of spironolactone.

Aldosterone renin ratio and chronic kidney disease

As a component of the metabolic syndrome, hypertension (HTN) is increasing throughout the world with variable percentages, but mostly among developing world. Aldosterone plays a role in the relationship between aldosterone and nephropathy. We aimed to evaluate the relationship between aldosterone renin ratio (ARR) and chronic kidney disease (CKD). Variables drawn from the computerized hospital information database were all patients who had an ARR above 35 (if aldosterone reading was above 300 pmol/L). A total of 1584 patients, of whom 777 were male and 807 were female, with a mean [standard deviation (SD)] of 43.3 (16.5) years were studied. The mean ARR was 210.1 (SD: 246.4) in males and 214.3 and 210.1 in females, P = 0.51. The mean estimated glomerular filtration rate (eGFR) was 50.2 (SD 12.6); in males, it was 49.99 (0.90) and in females, it was 50.48 (0.92), P = 0.70. The regression model revealed a negative relationship between ARR and GFR with a coefficient of -2.08, 95% confidence interval: -4.6, 0.21, P = 0.07. CKD population with HTN tends to have a very high level of ARR, and those with advanced CKD have higher ARR. However, high ARR could have low eGFR and kidney dysfunction on follow-up. In view of high prevalence of noncommunicable disease and high early CKD population, there is an important need to consider comprehensive management strategies that involve the blockage of high renin-angiotensin-aldosterone and the use of mineralocorticosteroid receptor blockers.

Quantum dots modulate intracellular Ca2+ level in lung epithelial cells

While adverse effects of nanoparticles on lung health have previously been proposed, few studies have addressed the direct effects of nanoparticle exposure on the airway epithelium. In this work, we examine the response of the pulmonary airway to nanoparticles by measuring intracellular Ca²⁺ concentration ([Ca²⁺]_i) in the Calu-3 epithelial layer stimulated by 3-mercaptopropionic-acid (3MPA) coated CdSe-CdS/ZnS core-multishell quantum dots (QDs). Simultaneous transient transepithelial electrical resistance (TEER) decrease and global [Ca²⁺]_i increase in Calu-3 epithelial layer, accompanied by cell displacements, contraction, and expansion, were observed under QD deposition. This suggests that a QD-induced global [Ca²⁺]_i increase in the Calu-3 epithelial layer caused the transient TEER decrease. The [Ca²⁺]_i increase was marked and rapid in the apical region, while [Ca²⁺]_i decreased in the basolateral region of the epithelial layer. TEER transient response and extracellular Ca²⁺ entry induced by QD deposition were completely inhibited in cells treated with stretched-activated (SA) inhibitor GdCl₃ and store-operated calcium entry (SOCE) inhibitor BTP2 and in cells immersed in Ca²⁺-free medium. The voltage-gated calcium channel (VGCC) inhibitor nifedipine decreased, stabilized, and suppressed the TEER response, but did not affect the [Ca²⁺]_i increase, due to QD deposition. This demonstrates that the Ca²⁺ influx activated by QDs’ mechanical stretch occurs through activation of both SA and SOCE channels. QD-induced [Ca²⁺]_i increase occurred in the Calu-3 epithelial layer after culturing for 15 days, while significant TEER drop only occurred after 23 days. This work provides a new perspective from which to study direct interactions between airway epithelium and nanoparticles and may help to reveal the pathologies of pulmonary disease.

Third-generation Mineralocorticoid Receptor Antagonists: Why Do We Need a Fourth?

The first mineralocorticoid receptor (MR) antagonist, spironolactone, was developed almost 60 years ago to treat primary aldosteronism and pathological edema. Its use waned in part because of its lack of selectivity. Subsequently, knowledge of the scope of MR function was expanded along with clinical evidence of the therapeutic importance of MR antagonists to prevent the ravages of inappropriate MR activation. Forty-two years elapsed between the first and MR-selective second generation of MR antagonists. Fifteen years later, despite serious shortcomings of the existing antagonists, a third-generation antagonist has yet to be marketed. Progress has been slowed by the lack of appreciation of the large variety of cell types that express the MR and its diverse cell-type-specific actions, and also its unique complex interaction actions at the molecular level. New MR antagonists should preferentially target the inflammatory and fibrotic effects of MR and perhaps its excitatory effects on sympathetic nervous system, but not the renal tubular epithelium or neurons of the cortex and hippocampus. This review briefly describes efforts to develop a third-generation MR antagonist and why fourth generation antagonists and selective agonists based on structural determinants of tissue and ligand-specific MR activation should be contemplated.

Aldosterone in vascular and metabolic dysfunction

PURPOSE OF REVIEW

This review will highlight recent developments in mineralocorticoid receptor research which impact aldosterone-associated vascular and cardiometabolic dysfunction.

RECENT FINDINGS

The mineralocorticoid receptor is also expressed in vascular smooth muscle and vascular endothelium, and contributes to vascular function and remodeling. Adipocyte-derived leptin stimulates aldosterone secretion, which may explain the observed link between obesity and hyperaldosteronism. Adipocyte mineralocorticoid receptor overexpression produces systemic changes consistent with metabolic syndrome. Ongoing studies with novel nonsteroidal mineralocorticoid receptor antagonists may provide a novel treatment for diabetic nephropathy and heart failure in patients with chronic kidney disease, with reduced risk of hyperkalemia.

SUMMARY

Ongoing research continues to demonstrate novel roles of the vascular and adipocyte mineralocorticoid receptor function, which may explain the beneficial metabolic and vascular benefits of mineralocorticoid receptor antagonists.

Pharmacological profile of CS-3150, a novel, highly potent and selective non-steroidal mineralocorticoid receptor antagonist

The present study was designed to characterize the pharmacological profile of CS-3150, a novel non-steroidal mineralocorticoid receptor antagonist. In the radioligand-binding assay, CS-3150 inhibited (3)H-aldosterone binding to mineralocorticoid receptor with an IC50 value of 9.4nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 36 and 713nM, respectively. CS-3150 also showed at least 1000-fold higher selectivity for mineralocorticoid receptor over other steroid hormone receptors, glucocorticoid receptor, androgen receptor and progesterone receptor. In the reporter gene assay, CS-3150 inhibited aldosterone-induced transcriptional activation of human mineralocorticoid receptor with an IC50 value of 3.7nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 66 and 970nM, respectively. CS-3150 had no agonistic effect on mineralocorticoid receptor and did not show any antagonistic or agonistic effect on glucocorticoid receptor, androgen receptor and progesterone receptor even at the high concentration of 5μM. In adrenalectomized rats, single oral administration of CS-3150 suppressed aldosterone-induced decrease in urinary Na(+)/K(+) ratio, an index of in vivo mineralocorticoid receptor activation, and this suppressive effect was more potent and longer-lasting than that of spironolactone and eplerenone. Chronic treatment with CS-3150 inhibited blood pressure elevation induced by deoxycorticosterone acetate (DOCA)/salt-loading to rats, and this antihypertensive effect was more potent than that of spironolactone and eplerenone. These findings indicate that CS-3150 is a selective and highly potent mineralocorticoid receptor antagonist with long-lasting oral activity. This agent could be useful for the treatment of hypertension, cardiovascular and renal disorders.