Natriuretic Peptide Processing in Patients with and Without Left Ventricular Dysfunction

Augmentation of natriuretic peptide (NP) receptor A and B (NPR-A and NPR-B) and cyclic guanosine monophosphate (cGMP) signalling as a therapeutic strategy in heart failure

INTRODUCTION

Heart failure is a complex, debilitating condition and despite advances in treatment, it remains a significant cause of morbidity and mortality worldwide. Therefore, the need for alternative treatment strategies is essential. In this review, we explore the therapeutic strategies of augmenting natriuretic peptide receptors (NPR-A and NPR-B) and cyclic guanosine monophosphate (cGMP) in heart failure.

AREAS COVERED

We aim to provide an overview of the evidence of preclinical and clinical studies on novel heart failure treatment strategies. Papers collected in this review have been filtered and screened following PubMed searches. This includes epigenetics, modulating enzyme activity in natriuretic peptide (NP) synthesis, gene therapy, modulation of downstream signaling by augmenting soluble guanylate cyclase (sGC) and phosphodiesterase (PDE) inhibition, nitrates, c-GMP-dependent protein kinase, synthetic and designer NP and RNA therapy.

EXPERT OPINION

The novel treatment strategies mentioned above have shown great potential, however, large randomized controlled trials are still lacking. The biggest challenge is translating the results seen in preclinical trials into clinical trials. We recommend a multi-disciplinary team approach with cardiologists, geneticist, pharmacologists, bioengineers, researchers, regulators, and patients to improve heart failure outcomes. Future management can involve telemedicine, remote monitoring, and artificial intelligence to optimize patient care.

Role of Cardiac Natriuretic Peptides in Heart Structure and Function

Cardiac natriuretic peptides (NPs), atrial NP (ANP) and B-type NP (BNP) are true hormones produced and released by cardiomyocytes, exerting several systemic effects. Together with C-type NP (CNP), mainly expressed by endothelial cells, they also exert several paracrine and autocrine activities on the heart itself, contributing to cardiovascular (CV) health. In addition to their natriuretic, vasorelaxant, metabolic and antiproliferative systemic properties, NPs prevent cardiac hypertrophy, fibrosis, arrhythmias and cardiomyopathies, counteracting the development and progression of heart failure (HF). Moreover, recent studies revealed that a protein structurally similar to NPs mainly produced by skeletal muscles and osteoblasts called musclin/osteocrin is able to interact with the NPs clearance receptor, attenuating cardiac dysfunction and myocardial fibrosis and promoting heart protection during pathological overload. This narrative review is focused on the direct activities of this molecule family on the heart, reporting both experimental and human studies that are clinically relevant for physicians.

Edema formation in congestive heart failure and the underlying mechanisms

Congestive heart failure (HF) is a complex disease state characterized by impaired ventricular function and insufficient peripheral blood supply. The resultant reduced blood flow characterizing HF promotes activation of neurohormonal systems which leads to fluid retention, often exhibited as pulmonary congestion, peripheral edema, dyspnea, and fatigue. Despite intensive research, the exact mechanisms underlying edema formation in HF are poorly characterized. However, the unique relationship between the heart and the kidneys plays a central role in this phenomenon. Specifically, the interplay between the heart and the kidneys in HF involves multiple interdependent mechanisms, including hemodynamic alterations resulting in insufficient peripheral and renal perfusion which can lead to renal tubule hypoxia. Furthermore, HF is characterized by activation of neurohormonal factors including renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system (SNS), endothelin-1 (ET-1), and anti-diuretic hormone (ADH) due to reduced cardiac output (CO) and renal perfusion. Persistent activation of these systems results in deleterious effects on both the kidneys and the heart, including sodium and water retention, vasoconstriction, increased central venous pressure (CVP), which is associated with renal venous hypertension/congestion along with increased intra-abdominal pressure (IAP). The latter was shown to reduce renal blood flow (RBF), leading to a decline in the glomerular filtration rate (GFR). Besides the activation of the above-mentioned vasoconstrictor/anti-natriuretic neurohormonal systems, HF is associated with exceptionally elevated levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). However, the supremacy of the deleterious neurohormonal systems over the beneficial natriuretic peptides (NP) in HF is evident by persistent sodium and water retention and cardiac remodeling. Many mechanisms have been suggested to explain this phenomenon which seems to be multifactorial and play a major role in the development of renal hyporesponsiveness to NPs and cardiac remodeling. This review focuses on the mechanisms underlying the development of edema in HF with reduced ejection fraction and refers to the therapeutic maneuvers applied today to overcome abnormal salt/water balance characterizing HF.

Corin: A Key Mediator in Sodium Homeostasis, Vascular Remodeling, and Heart Failure

Simple Summary

Atrial natriuretic peptide (ANP) is an important hormone that regulates many physiological and pathological processes, including electrolyte and body fluid balance, blood volume and pressure, cardiac channel activity and function, inflammatory response, lipid metabolism, and vascular remodeling. Corin is a transmembrane serine protease that activates ANP. Variants in the CORIN gene are associated with cardiovascular disease, including hypertension, cardiac hypertrophy, atrial fibrillation, heart failure, and preeclampsia. The current data indicate a key role of corin-mediated ANP production and signaling in the maintenance of cardiovascular homeostasis. In this review, we discuss the latest findings regarding the molecular and cellular mechanisms underlying the role of corin in sodium homeostasis, uterine spiral artery remodeling, and heart failure.

Abstract

Atrial natriuretic peptide (ANP) is a crucial element of the cardiac endocrine function that promotes natriuresis, diuresis, and vasodilation, thereby protecting normal blood pressure and cardiac function. Corin is a type II transmembrane serine protease that is highly expressed in the heart, where it converts the ANP precursor to mature ANP. Corin deficiency prevents ANP activation and causes hypertension and heart disease. In addition to the heart, corin is expressed in other tissues, including those of the kidney, skin, and uterus, where corin-mediated ANP production and signaling act locally to promote sodium excretion and vascular remodeling. These results indicate that corin and ANP function in many tissues via endocrine and autocrine mechanisms. In heart failure patients, impaired natriuretic peptide processing is a common pathological mechanism that contributes to sodium and body fluid retention. In this review, we discuss most recent findings regarding the role of corin in non-cardiac tissues, including the kidney and skin, in regulating sodium homeostasis and body fluid excretion. Moreover, we describe the molecular mechanisms underlying corin and ANP function in supporting orderly cellular events in uterine spiral artery remodeling. Finally, we assess the potential of corin-based approaches to enhance natriuretic peptide production and activity as a treatment of heart failure.

Evaluation of CORIN in patients with heart failure: A systematic review and meta-analysis

Objectives: We aim to evaluate the association between CORIN and heart failure.

Methods: This study used PubMed, EMBASE, Cochrane database, and China National Knowledge Database (CNKI) to search for CORIN-related full-text articles with heart failure patients. We drew forest plots, performed sensitivity and bias analyses based on the included data. Next, we used Review Manager 5.2 software to assess the heterogeneity among selected articles.

Results: Our meta-analysis results showed there was significant relationship between CORIN and heart failure (HF). There was significant difference of CORIN between heart failure group and control group (MD = −293.88, 95% confidence interval [-380.26, −207.49], p < .00001; heterogeneity p < .0001, I2= 97%) and there was significant difference in CORIN between ischemic group and non-ischemic group (MD = 88.79, 95% confidence interval [70.46107.12], heterogeneity p < .000, p = 0.94, l2= 0%). In subgroup analysis, there were significant differences in three different HF levels. Limited publication bias was observed, and this study was robust.

Conclusion: In short, the results showed that CORIN was closely related with heart failure and might be helpful in the diagnosis of heart failure.

An Robust Rank Aggregation and Least Absolute Shrinkage and Selection Operator Analysis of Novel Gene Signatures in Dilated Cardiomyopathy

Objective: Dilated cardiomyopathy (DCM) is a heart disease with high mortality characterized by progressive cardiac dilation and myocardial contractility reduction. The molecular signature of dilated cardiomyopathy remains to be defined. Hence, seeking potential biomarkers and therapeutic of DCM is urgent and necessary.

Methods: In this study, we utilized the Robust Rank Aggregation (RRA) method to integrate four eligible DCM microarray datasets from the GEO and identified a set of significant differentially expressed genes (DEGs) between dilated cardiomyopathy and non-heart failure. Moreover, LASSO analysis was carried out to clarify the diagnostic and DCM clinical features of these genes and identify dilated cardiomyopathy derived diagnostic signatures (DCMDDS).

Results: A total of 117 DEGs were identified across the four microarrays. Furthermore, GO analysis demonstrated that these DEGs were mainly enriched in the regulation of inflammatory response, the humoral immune response, the regulation of blood pressure and collagen–containing extracellular matrix. In addition, KEGG analysis revealed that DEGs were mainly enriched in diverse infected signaling pathways. Moreover, Gene set enrichment analysis revealed that immune and inflammatory biological processes such as adaptive immune response, cellular response to interferon and cardiac muscle contraction, dilated cardiomyopathy are significantly enriched in DCM. Moreover, Least absolute shrinkage and selection operator (LASSO) analyses of the 18 DCM-related genes developed a 7-gene signature predictive of DCM. This signature included ANKRD1, COL1A1, MYH6, PERELP, PRKACA, CDKN1A, and OMD. Interestingly, five of these seven genes have a correlation with left ventricular ejection fraction (LVEF) in DCM patients.

Conclusion: Our present study demonstrated that the signatures could be robust tools for predicting DCM in clinical practice. And may also be potential treatment targets for clinical implication in the future.

Distribution of Cardiac and Renal Corin and Proprotein Convertase Subtilisin/Kexin-6 in the Experimental Model of Cardio-Renal Syndrome of Various Severities

Congestive heart failure (CHF) often leads to progressive cardiac hypertrophy and salt/water retention. However, its pathogenesis remains largely unclarified. Corin, a cardiac serine protease, is responsible for converting proANP and proBNP to biologically active peptides. Although the involvement of corin in cardiac hypertrophy and heart failure was extensively studied, the alterations in corin and proprotein convertase subtilisin/kexin-6 (PCSK6), a key enzyme in the conversion of procorin to corin, has not been studied simultaneously in the cardiac and renal tissues in cardiorenal syndrome. Thus, this study aims to examine the status of PCSK6/corin in the cardiac and renal tissues of rats with CHF induced by the creation of aorto-caval fistula (ACF). We divided rats with ACF into two subgroups based on the pattern of their urinary sodium excretion, namely, compensated and decompensated. Placement of ACF led to cardiac hypertrophy, pulmonary congestion, and renal dysfunction, which were more profound in the decompensated subgroup. Corin immunoreactive peptides were detected in all heart chambers at the myocyte membranal and cytosolic localization and in the renal tissue, especially in the apical membrane of the proximal tubule, mTAL, and the collecting duct. Interestingly, the expression and abundance of corin in both the cardiac ventricles and renal tissues were significantly increased in compensated animals as compared with the decompensated state. Noteworthy, the abundance of PCSK6 in these tissues followed a similar pattern as corin. In contrast, furin expression was upregulated in the cardiac and renal tissues in correlation with CHF severity. We hypothesize that the obtained upregulation of cardiac and renal PCSK6/corin in rats with compensated CHF may represent a compensatory response aiming at maintaining normal Na⁺ balance, whereas the decline in these two enzymes may contribute to the pathogenesis of avid sodium retention, cardiac hypertrophy, and blunted atrial natriuretic peptide/brain natriuretic peptide actions in decompensated CHF.

Single-Nucleotide Polymorphisms in the 3' Untranslated Region of CORIN Associated With Cardiovascular Diseases in a Chinese Han Population: A Case-Control Study

Background: Corin is a transmembrane serine protease that activates pro-forms of atrial and brain natriuretic peptides. Numerous studies have indicated that corin played an important role in cardiovascular diseases (CVDs). However, there have been few studies about the correlation between single-nucleotide polymorphisms (SNPs) in the 3' untranslated region (3'UTR) of CORIN and CVDs. The aims of this study were to investigate the associations of three SNPs (rs3749585, rs4695253, and rs12641823) in the 3'UTR of CORIN with CVDs and to find the seed regions of microRNAs (miRNAs) that bind to SNPs of CORIN.

Methods and Results: A case–control study (n = 3,537) was performed in a Han population of northeastern China. CVDs included essential hypertension (EH), atrial fibrillation (AF), heart failure (HF), and coronary artery disease (CAD). Genotyping was performed using high-resolution melt analysis. In the EH-control study, rs3749585^T was significantly associated with the risk of EH after adjusting for sex and age in allelic (p_adj = 0.049; OR: 1.113) and dominant (p_adj = 0.015, OR: 1.233) models. Rs4695253^T was significantly associated with the risk of EH in the recessive model after adjusting for sex and age (p_adj = 0.005, OR: 2.084). Rs3749585^T was significantly and negatively associated with AF in the dominant and additive models after adjusting for sex, age, EH, HF, T2DM, and CAD (dominant: p_adj = 0.009, OR: 0.762; additive: p_adj = 0.048, OR: 0.873). In the HF-control study and CAD-control study, none of the three SNPs was associated with HF and CAD after adjusting for covariates in any models (p_adj > 0.05). The levels of high-density lipoprotein (HDL) in rs4695253^CC+CT were lower than the levels of HDL in rs4695253^TT (42.47 ± 10.30 vs. 48.0 ± 10.24 mg/dl, p_adj = 0.008). The levels of total cholesterol (TC) in rs4695253^CC+CT were lower than the levels of TC in rs4695253^TT (164.01 ± 49.15 vs. 180.81 ± 43.92 mg/dl, p_adj = 0.036). Luciferase assay revealed that the relative luciferase activity of rs3749585^CC-transfected cells was significantly decreased by miR-494-3p, in comparison to cells transfected with rs3749585^TT (p < 0.001). A significant decrease in the relative luciferase activity of rs3749585^TT reporter was observed as compared with rs3749585^CC reporter in the presence of miR-1323 or miR-548o-3p (p = 0.017 and 0.012, respectively).

Conclusions: We found significant associations between rs3749585^T and rs4695253^T and EH, between rs4695253^T and the levels of TC and HDL, and between rs3749585^T and AF. Hsa-miR-494-3p may serve as a potential therapeutic target for EH and AF patients in the future.

Function and regulation of corin in physiology and disease

Atrial natriuretic peptide (ANP) is of major importance in the maintenance of electrolyte balance and normal blood pressure. Reduced plasma ANP levels are associated with the increased risk of cardiovascular disease. Corin is a type II transmembrane serine protease that converts the ANP precursor to mature ANP. Corin deficiency prevents ANP generation and alters electrolyte and body fluid homeostasis. Corin is synthesized as a zymogen that is proteolytically activated on the cell surface. Factors that disrupt corin folding, intracellular trafficking, cell surface expression, and zymogen activation are expected to impair corin function. To date, CORIN variants that reduce corin activity have been identified in hypertensive patients. In addition to the heart, corin expression has been detected in non-cardiac tissues, where corin and ANP participate in diverse physiological processes. In this review, we summarize the current knowledge in corin biosynthesis and post-translational modifications. We also discuss tissue-specific corin expression and function in physiology and disease.

Recombinant Soluble Corin Improves Cardiac Function in Mouse Models of Heart Failure

Background

Corin is a transmembrane protease that activates ANP and BNP (atrial and B‐type natriuretic peptides). Impaired corin expression and function are associated with heart failure. In this study, we characterized a soluble form of corin (sCorin) and examined its effects on cardiac morphology and function in mouse heart failure models.

Methods and Results

sCorin, consisting of the full‐length extracellular fragment of human corin with an engineered activation site, was expressed in Chinese hamster ovary cells, purified from the conditioned medium with affinity chromatography, and characterized in pro‐ANP processing assays in vitro and pharmacokinetic studies in mice. Effects of sCorin on mouse models of heart failure induced by left coronary artery ligation and transverse aortic constriction were assessed by ELISA analysis of plasma markers, histologic examination, and echocardiography. We showed that purified and activated sCorin converted pro‐ANP to ANP that stimulated cGMP production in cultured cells. In mice, intravenously and intraperitoneally administered sCorin had plasma half‐lives of 3.5±0.1 and 8.3±0.3 hour, respectively. In the mouse heart failure models, intraperitoneal injection of sCorin increased plasma ANP, BNP, and cGMP levels; lowered plasma levels of NT‐proANP (N‐terminal‐pro‐ANP), angiotensin II, and aldosterone; reduced cardiac hypertrophy and fibrosis; and improved cardiac function.

Conclusions

We show that sCorin treatment enhanced natriuretic peptide processing and activity, suppressed the renin‐angiotensin‐aldosterone system, and improved cardiac morphology and function in mice with failing hearts.

Cardiac-Specific Overexpression of Catalytically Inactive Corin Reduces Edema, Contractile Dysfunction, and Death in Mice with Dilated Cardiomyopathy

Humans with dilated cardiomyopathy (DCM) and heart failure (HF) develop low levels of corin, a multi-domain, cardiac-selective serine protease involved in natriuretic peptide cleavage and sodium and water regulation. However, experimental restoration of corin levels markedly attenuates HF progression. To determine whether the beneficial effects of corin in HF require catalytic activity, we engineered cardiac overexpression of an enzymatically inactive corin transgene (corin-Tg(i)). On a wild-type (WT) background, corin-Tg(i) had no evident phenotypic effects. However, in a well-established genetic model of DCM, corin-Tg(i)/DCM mice had increased survival (p < 0.01 to 0.001) vs. littermate corin-WT/DCM controls. Pleural effusion (p < 0.01), lung edema (p < 0.05), systemic extracellular free water (p < 0.01), and heart weight were decreased (p < 0.01) in corin-Tg(i)/DCM vs. corin-WT/DCM mice. Cardiac ejection fraction and fractional shortening improved (p < 0.01), while ventricular dilation decreased (p < 0.0001) in corin-Tg(i)/DCM mice. Plasma atrial natriuretic peptide, cyclic guanosine monophosphate, and neprilysin were significantly decreased. Cardiac phosphorylated glycogen synthase kinase-3β (pSer9-GSK3β) levels were increased in corin(i)-Tg/DCM mice (p < 0.01). In summary, catalytically inactive corin-Tg(i) decreased fluid retention, improved contractile function, decreased HF biomarkers, and diminished cardiac GSK3β activity. Thus, the protective effects of cardiac corin on HF progression and survival in experimental DCM do not require the serine protease activity of the molecule.