MiR30-GALNT1/2 Axis-Mediated Glycosylation Contributes to the Increased Secretion of Inactive Human Prohormone for Brain Natriuretic Peptide (proBNP) From Failing Hearts

Coronary microcirculation in myocardial ischemia: A genetic perspective

Coronary microvascular dysfunction (CMD) is a major contributor to ischemic heart disease (IHD), acting both independently and together with atherosclerosis. CMD encompasses structural and functional microcirculatory changes that result in dysregulated coronary blood flow. Structural abnormalities include microvascular remodeling, resulting in arteriolar and capillary narrowing, perivascular fibrosis and capillary rarefaction. Endothelial dysfunction and smooth muscle cell hyperactivity further impair microcirculation. Genetic factors may play a crucial role in the pathophysiology of CMD, mainly due to single nucleotide polymorphisms (SNPs) in genes that regulate coronary blood flow and microcirculation structural modifications. This manuscript aims to review the genetic determinants of CMD, with particular focus on ion channels, microRNAs (miRNAs), and proteins involved in the endothelial environment. The improving knowledge about genetic aspects of CMD opens the possibility to have new biomarkers, improving diagnosis and the development of targeted treatments in light of an even more patient-tailored approach.

Musclin Counteracts Skeletal Muscle Dysfunction and Exercise Intolerance in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Exercise intolerance is a hallmark of heart failure with preserved ejection fraction (HFpEF) and is characterized by skeletal muscle (SkM) dysfunction with impaired oxidative capacity. To maintain oxidative capacity, the SkM secretes myokines such as musclin, which has been shown to potentiate NP (natriuretic peptide) signaling and induce PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1 alpha) signaling. We sought to investigate the role of musclin in SkM dysfunction in HFpEF. For this study, we selected the oxidative-predominant SkM soleus in HFpEF mice and vastus lateralis from patients with HFpEF.

METHODS

Using the SAUNA model, mice underwent HFpEF induction by uninephrectomy, d-aldosterone infusion, and 1% sodium chloride drinking water for 4 weeks. Exogenous musclin was given to HFpEF mice every 2 days during the last 2 weeks of HFpEF induction. Molecular analyses were conducted on blood samples and SkM from HFpEF mice and patients with HFpEF.

RESULTS

In HFpEF mice and patients with HFpEF, increased musclin expression was accompanied by decreased cyclic guanosine monophosphate levels and PGC-1α expression in SkM, suggesting impaired NP signaling. Exogenous administration of musclin in mice with HFpEF demonstrated augmented circulating musclin levels and potentiated NP signaling in SkM as shown by increased PKG1 (protein kinase G1) activity and PGC-1α expression. This was associated with a transition from type-2A to type-1 fiber (type-1 has more endurance) and increased succinate dehydrogenase activity, hindlimb blood flow, and capillary density in the soleus muscle. Exogenous musclin also mitigated cardiac hypertrophy without affecting blood pressure or diastolic function. Most importantly, HFpEF mice treated with musclin demonstrated improved functional and exercise capacity.

CONCLUSIONS

Musclin mediates beneficial effects in SkM and heart with improved exercise capacity likely by improving oxidative capacity in SkM. Future studies are warranted to address the therapeutic efficacy of exogenous musclin in humans with HFpEF.

Responses of B-type natriuretic peptide (BNP), mature BNP and proBNP to sacubitril/valsartan differs between responders and non-responders

BACKGROUND

Earlier studies showed that measured changes in plasma B-type natriuretic peptide (BNP) levels are inconsistent after sacubitril/valsartan administration. The reason remains unknown but may reflect the fact that BNP immunoreactivity measured with commercial BNP assays (BNPcom) includes both mature BNP and proBNP, and neprilysin degrades only mature BNP. In addition, the responsiveness to sacubitril/valsartan varies among patients with heart failure. We investigated the mechanism underlying the inconsistency of BNP measurements after sacubitril/valsartan.

METHODS

We measured plasma mature BNP, proBNP and total BNP (mature BNP+proBNP) levels with our immunochemiluminescent assay as well as NT-proBNP, A-type natriuretic peptide (ANP) and BNPcom with conventional assays in 54 patients with heart failure, before (baseline) and after 2, 4, 8 and 12 weeks of sacubitril/valsartan administration. Responders were defined as having NT-proBNP levels at <70% of baseline after 12 weeks.

RESULTS

Among all patients, total BNP and BNPcom did not change with sacubitril/valsartan treatment, whereas NT-proBNP and proBNP decreased, mature BNP modestly increased and ANP greatly increased. Responders (n=31) exhibited smaller %changes in all natriuretic peptide levels than non-responders (n=23; all p<0.01). Receiver operating characteristic curves analysis to assess the ability of the %change in each natriuretic peptide at 4 weeks to detect responders showed that the area under the curve was about 0.80 for each peptide. There were good correlations between plasma natriuretic peptides levels at baseline and throughout the sacubitril/valsartan administration.

CONCLUSION

These results suggest that the magnitude and direction of change in each BNP form depends on its substrate specificity for neprilysin, that differences in plasma levels of each BNP form between responders and non-responders appear early and persist and that BNPcom levels at 4 weeks can be applicable to prediction of the responders. Notably, our findings show that the idea that BNPcom cannot be used as a marker of heart failure after sacubitril/valsartan should be reconsidered.

Cellular and molecular biology of posttranslational modifications in cardiovascular disease

Cardiovascular disease (CVD) has now become the leading cause of death worldwide, and its high morbidity and mortality rates pose a great threat to society. Although numerous studies have reported the pathophysiology of CVD, the exact pathogenesis of all types of CVD is not fully understood. Therefore, much more research is still needed to explore the pathogenesis of CVD. With the development of proteomics, many studies have successfully identified the role of posttranslational modifications in the pathogenesis of CVD, including key processes such as apoptosis, cell metabolism, and oxidative stress. In this review, we summarize the progress in the understanding of posttranslational modifications in cardiovascular diseases, including novel protein posttranslational modifications such as succinylation and nitrosylation. Furthermore, we summarize the currently identified histone deacetylase (HDAC) inhibitors used to treat CVD, providing new perspectives on CVD treatment modalities. We critically analyze the roles of posttranslational modifications in the pathogenesis of CVD-related diseases and explore future research directions related to posttranslational modifications in cardiovascular diseases.

MicroRNA-30d and -483-3p for bi-ventricular remodelling and miR-126-3p for pulmonary hypertension in advanced heart failure

AIMS

MicroRNAs play a role in pathogenic mechanisms leading to heart failure. We measured a panel of 754 miRNAs in the myocardial tissue and in the serum of patients with heart failure with reduced ejection fraction due to dilatative idiopathic cardiomyopathy (DCM, N = 10) or ischaemic cardiomyopathy (N = 3), referred to left ventricular assist device implant. We aim to identify circulating miRNAs with high tissue co-expression, significantly associated to echocardiographic and haemodynamic measures.

METHODS AND RESULTS

We have measured a panel of 754 miRNAs in the myocardial tissue [left ventricular (LV) apex] and in the serum obtained at the same time in a well selected study population of end-stage heart failure with reduced ejection fraction due to either DCM or ischaemic cardiomyopathy, referred to continuous flow left ventricular assist device implant. We observed moderate agreement for miR-30d, miR-126-3p, and miR-483-3p. MiR-30d was correlated to LV systolic as well as diastolic volumes (r = 0.78, P = 0.001 and r = 0.80, P = 0.005, respectively), while miR-126-3p was associated to mPAP and PCWP (r = -0.79, P = 0.007 and r = -0.80, P = 0.005, respectively). Finally, serum miR-483-3p had an association with right ventricular end diastolic diameter (r = -0.73, P = 0.02) and central venous pressure (CVP) (r - 0.68 p 0.03).

CONCLUSIONS

In patients with DCM, few miRNAs are co-expressed in serum and tissue: They are related to LV remodelling (miR-30d), post-capillary pulmonary artery pressure (miR-126-3p), and right ventricular remodelling/filling pressures (miR-483-3p). Further studies are needed to confirm their role in diagnosis, prognosis or as therapeutic targets in heart failure with reduced ejection fraction.

MicroRNA-124 conducts neuroprotective effect via inhibiting AK4/ATF3 after subarachnoid hemorrhage

Spontaneous subarachnoid hemorrhage (SAH) accounts for approximately 5% of all cases of stroke. SAH is correlated with elevated rates of mortality and disability. Despite significant advancements in comprehending the pathogenesis and surgical management, efficacious clinical interventions remain restricted, and the prognosis is yet to be enhanced. MicroRNAs play a crucial role in various pathological processes in organisms. Revealing these regulatory processes is conducive to the development of new treatment methods. MicroRNA-124 is highly expressed in the nervous system and has significant research value for SAH. This study aims to explore the role of miR-124 in the early post-SAH period on neural function and verify whether it is involved in the pathological and physiological processes of SAH. In this study, we used methods such as comparing the expression levels of miR-124 in cerebrospinal fluid, establishing a rat SAH model, and a mouse embryonic primary neuron hemoglobin stimulation model to verify the downstream proteins of miR-124 in SAH. Through transfection techniques, we adjusted the expression of this small RNA in Vitro and in Vivo models using miR-124 inhibitor and mimic in the primary neuron hemoglobin stimulation model and rat SAH model, and observed the phenotype. Finally, by consulting the literature and verifying in Vivo and in Vitro methods, AK4 and downstream molecule ATF3 were identified as downstream targets of miR-124.

Natriuretic Peptide Receptors (NPRs) as a Potential Target for the Treatment of Heart Failure

PURPOSE OF REVIEW

Heart failure is defined as a complex clinical syndrome that results from any structural or functional impairment of ventricular filling or ejection of blood. The natriuretic peptide is known to exert its biological action on the kidney, heart, blood vessels, renin-angiotensin system, autonomous nervous system, and central nervous system. The natriuretic peptide-natriuretic receptor system plays an important role in the regulation of blood pressure and body fluid volume through its pleiotropic effects.

RECENT FINDINGS

The clinical and animal studies suggest that natriuretic peptide-natriuretic receptors are important targets for the treatment of heart failure and other cardiovascular diseases. Even though attempts targeting natriuretic peptide receptors are underway for heart failure treatment, they seem insufficient despite the receptor systems' potential. This review summarizes natriuretic peptide-natriuretic receptor system's physiological actions and potential target for the treatment of heart failure. Natriuretic peptides play multiple roles in different parts of the body, almost all of the activities related to this receptor system appear to have the potential to be harnessed to treat heart failure or symptoms associated with heart failure.

Natriuretic Peptides: It Is Time for Guided Therapeutic Strategies Based on Their Molecular Mechanisms

Natriuretic peptides (NPs) are the principal expression products of the endocrine function of the heart. They exert several beneficial effects, mostly mediated through guanylate cyclase-A coupled receptors, including natriuresis, diuresis, vasorelaxation, blood volume and blood pressure reduction, and regulation of electrolyte homeostasis. As a result of their biological functions, NPs counterbalance neurohormonal dysregulation in heart failure and other cardiovascular diseases. NPs have been also validated as diagnostic and prognostic biomarkers in cardiovascular diseases such as atrial fibrillation, coronary artery disease, and valvular heart disease, as well as in the presence of left ventricular hypertrophy and severe cardiac remodeling. Serial measurements of their levels may be used to contribute to more accurate risk stratification by identifying patients who are more likely to experience death from cardiovascular causes, heart failure, and cardiac hospitalizations and to guide tailored pharmacological and non-pharmacological strategies with the aim to improve clinical outcomes. On these premises, multiple therapeutic strategies based on the biological properties of NPs have been attempted to develop new targeted cardiovascular therapies. Apart from the introduction of the class of angiotensin receptor/neprilysin inhibitors to the current management of heart failure, novel promising molecules including M-atrial natriuretic peptide (a novel atrial NP-based compound) have been tested for the treatment of human hypertension with promising results. Moreover, different therapeutic strategies based on the molecular mechanisms involved in NP regulation and function are under development for the management of heart failure, hypertension, and other cardiovascular conditions.

Diagnostic utility of total NT-proBNP testing by immunoassay based on antibodies targeting glycosylation-free regions of NT-proBNP

OBJECTIVES

The N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) is a widely used heart failure (HF) biomarker. Commercial NT-proBNP immunoassays detect only a subfraction of endogenous NT-proBNP, as the antibodies target a region of NT-proBNP that could be glycosylated at Ser44. The diagnostic utility of immunoassays measuring total NT-proBNP remains unclear.

METHODS

NT-proBNP was measured in 183 HF and 200 non-HF patients diagnosed by two independent cardiologists blinded to NT-proBNP results. Plasma samples either non-treated or treated with a mixture of glycosidases were analyzed by the Elecsys proBNP II assay (Roche Diagnostics, based on antibodies targeting a glycosylated region of NT-proBNP) and the SuperFlex NT-proBNP assay (PerkinElmer, based on antibodies targeting regions of NT-proBNP that are free of O-glycans). The diagnostic accuracy of the two assays was analyzed by comparison of ROC curves.

RESULTS

The ROC-AUC for the proBNP II assay was 0.943 (95% CI 0.922-0.964) for NT-proBNP measured in untreated samples and 0.935 (0.913-0.958) for NT-proBNP measured in glycosidase-treated samples. The SuperFlex NT-proBNP assay in untreated samples gave a ROC-AUC of 0.930 (95% CI 0.907-0.954). The median percentage of non-glycosylated NT-proBNP to total NT-proBNP was 1.5-1.6-fold lower in the non-HF group compared to that in the HF group.

CONCLUSIONS

The clinical value of total NT-proBNP for HF diagnosis was similar to the subfraction of NT-proBNP that was non-glycosylated at Ser44. The lower percentage of non-glycosylated NT-proBNP to total NT-proBNP in non-HF patients suggests that total NT-proBNP might be more sensitive in individuals without current or prior symptoms of HF.

Endocrine functions of the heart: from bench to bedside

Heart has a recognized endocrine function as it produces several biologically active substances with hormonal properties. Among these hormones, the natriuretic peptide (NP) system has been extensively characterized and represents a prominent expression of the endocrine function of the heart. Over the years, knowledge about the mechanisms governing their synthesis, secretion, processing, and receptors interaction of NPs has been intensively investigated. Their main physiological endocrine and paracrine effects on cardiovascular and renal systems are mostly mediated through guanylate cyclase-A coupled receptors. The potential role of NPs in the pathophysiology of heart failure and particularly their counterbalancing action opposing the overactivation of renin-angiotensin-aldosterone and sympathetic nervous systems has been described. In addition, NPs are used today as key biomarkers in cardiovascular diseases with both diagnostic and prognostic significance. On these premises, multiple therapeutic strategies based on the biological properties of NPs have been attempted to develop new cardiovascular therapies. Apart from the introduction of the class of angiotensin receptor/neprilysin inhibitors in the current management of heart failure, novel promising molecules, including M-atrial natriuretic peptide (a novel atrial NP-based compound), have been tested for the treatment of human hypertension. The development of new drugs is currently underway, and we are probably only at the dawn of novel NPs-based therapeutic strategies. The present article also provides an updated overview of the regulation of NPs synthesis and secretion by microRNAs and epigenetics as well as interactions of cardiac hormones with other endocrine systems.

Cardiovascular Alterations and Structural Changes in the Setting of Chronic Kidney Disease: a Review of Cardiorenal Syndrome Type 4

Cardiovascular and renal physiology are interrelated. More than a decade ago this was codified in guidelines defining the five subtypes of the cardiorenal syndrome. Morbidity and mortality for those with the cardiorenal syndrome is high compared to demographically matched individuals without cardiorenal disease, acute or chronic. The focus of this review will be the epidemiology, the impact of chronic kidney disease on cardiac structure and function, and associated clinical symptoms, outcomes, and potential treatments for patients with chronic reno-cardiac syndrome, or cardiorenal syndrome type 4. Cardiac structural changes can be profound and are described in detail both at a cellular and physiologic level. Integrating therapies for the treatment of causative or resulting comorbidities may ultimately slow progression of both cardiac and renal disease as well as minimize symptoms and death.

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.

Development of a joint diagnostic model of thyroid papillary carcinoma with artificial neural network and random forest

Objective: Papillary thyroid carcinoma (PTC) accounts for 80% of thyroid malignancy, and the occurrence of PTC is increasing rapidly. The present study was conducted with the purpose of identifying novel and important gene panels and developing an early diagnostic model for PTC by combining artificial neural network (ANN) and random forest (RF). Methods and results: Samples were searched from the Gene Expression Omnibus (GEO) database, and gene expression datasets (GSE27155, GSE60542, and GSE33630) were collected and processed. GSE27155 and GSE60542 were merged into the training set, and GSE33630 was defined as the validation set. Differentially expressed genes (DEGs) in the training set were obtained by "limma" of R software. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis as well as immune cell infiltration analysis were conducted based on DEGs. Important genes were identified from the DEGs by random forest. Finally, an artificial neural network was used to develop a diagnostic model. Also, the diagnostic model was validated by the validation set, and the area under the receiver operating characteristic curve (AUC) value was satisfactory. Conclusion: A diagnostic model was established by a joint of random forest and artificial neural network based on a novel gene panel. The AUC showed that the diagnostic model had significantly excellent performance.

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.

Assays Specific for BNP1-32 and NT-proBNP Exhibit a Similar Performance to Two Widely Used Assays in the Diagnosis of Heart Failure

BACKGROUND

Secretion of cardioprotective B-type natriuretic peptide 1-32 (BNP1-32) is increased proportionately with cardiac dysfunction, but its measurement in plasma is difficult. Therefore, less specific BNP and amino-terminal proBNP (NT-proBNP) assays that detect the precursor molecule proBNP alongside BNP or NT-proBNP metabolites were developed to reflect BNP1-32 secretion and are now mandated in the diagnosis of heart failure (HF). We compared the diagnostic performance of 2 widely used clinical assays: the Roche proBNPII assay, and Abbott BNP assay, against our recently developed in-house assays that measure either intact BNP1-32 or NT-proBNP.

METHODS

EDTA plasma samples obtained from patients presenting with breathlessness (n = 195, 60 [31%] with clinically adjudicated HF) were assayed using the Roche NT-proBNP and our specific in-house BNP1-32 and NTBNP assays. A subset (n = 75) were also assessed with the Abbott BNP assay.

RESULTS

Roche NT-proBNP was highly correlated with BNP1-32 and NTBNP (Spearman rho = 0.92 and 0.90, respectively, both Ps < 0.001), and all 3 assays similarly discriminated acute HF from other causes of breathlessness (ROC analysis areas under the curve 0.85-0.89). The Abbott BNP assay performed similarly to the other assays. Roche NT-proBNP and BNP1-32 assays had similar sensitivity (83% and 80%), specificity (83% and 84%), positive (70% and 71%) and negative (91% and 90%) predictive values, and accuracy (both 83%) at their optimal cutoffs of 1536 and 12 ng/L, respectively.

CONCLUSIONS

Since all assays exhibited similar performance in the diagnosis of HF, currently mandated assays provide a reliable proxy for circulating concentrations of active BNP1-32 in HF diagnosis.

Exogenous ANP Treatment Ameliorates Myocardial Insulin Resistance and Protects against Ischemia-Reperfusion Injury in Diet-Induced Obesity

Increasing evidence suggests natriuretic peptides (NPs) coordinate interorgan metabolic crosstalk. We recently reported exogenous ANP treatment ameliorated systemic insulin resistance by inducing adipose tissue browning and attenuating hepatic steatosis in diet-induced obesity (DIO). We herein investigated whether ANP treatment also ameliorates myocardial insulin resistance, leading to cardioprotection during ischemia-reperfusion injury (IRI) in DIO. Mice fed a high-fat diet (HFD) or normal-fat diet for 13 weeks were treated with or without ANP infusion subcutaneously for another 3 weeks. Left ventricular BNP expression was substantially reduced in HFD hearts. Intraperitoneal-insulin-administration-induced Akt phosphorylation was impaired in HFD hearts, which was restored by ANP treatment, suggesting that ANP treatment ameliorated myocardial insulin resistance. After ischemia-reperfusion using the Langendorff model, HFD impaired cardiac functional recovery with a corresponding increased infarct size. However, ANP treatment improved functional recovery and reduced injury while restoring impaired IRI-induced Akt phosphorylation in HFD hearts. Myocardial ultrastructural analyses showed increased peri-mitochondrial lipid droplets with concomitantly decreased ATGL and HSL phosphorylation levels in ANP-treated HFD, suggesting that ANP protects mitochondria from lipid overload by trapping lipids. Accordingly, ANP treatment attenuated mitochondria cristae disruption after IRI in HFD hearts. In summary, exogenous ANP treatment ameliorates myocardial insulin resistance and protects against IRI associated with mitochondrial ultrastructure modifications in DIO. Replenishing biologically active NPs substantially affects HFD hearts in which endogenous NP production is impaired.

Role of Posttranslational Modifications of Proteins in Cardiovascular Disease

Cardiovascular disease (CVD) has become a leading cause of mortality and morbidity globally, making it an urgent concern. Although some studies have been performed on CVD, its molecular mechanism remains largely unknown for all types of CVD. However, recent in vivo and in vitro studies have successfully identified the important roles of posttranslational modifications (PTMs) in various diseases, including CVD. Protein modification, also known as PTMs, refers to the chemical modification of specific amino acid residues after protein biosynthesis, which is a key process that can influence the activity or expression level of proteins. Studies on PTMs have contributed directly to improving the therapeutic strategies for CVD. In this review, we examined recent progress on PTMs and highlighted their importance in both physiological and pathological conditions of the cardiovascular system. Overall, the findings of this review contribute to the understanding of PTMs and their potential roles in the treatment of CVD.

B-Type Natriuretic Peptide (BNP) Revisited—Is BNP Still a Biomarker for Heart Failure in the Angiotensin Receptor/Neprilysin Inhibitor Era?

Simple Summary

Active BNP-32, less active proBNP-108, and inactive N-terminal proBNP-76 all circulate in the blood. The circulating protease neprilysin has lower substrate specificity for BNP than ANP, while proBNP and N-terminal proBNP are not degraded by neprilysin. Currently available BNP immunoassays react with both mature BNP and proBNP; therefore, measured plasma BNP is mature BNP + proBNP. Because ARNI administration increases mature BNP, measured plasma BNP initially increases with ARNI administration by the amount of the increase in mature BNP. Later, ARNI administration reduces myocardial wall stress, and the resultant reduction in BNP production more than offsets the increase of mature BNP due to inhibition of degradation by neprilysin, resulting in lower plasma BNP levels. In the ARNI era, BNP remains a useful biomarker for heart failure, though mild increases early during ARNI administration should be taken into consideration.

Abstract

Myocardial wall stress, cytokines, hormones, and ischemia all stimulate B-type (or brain) natriuretic peptide (BNP) gene expression. Within the myocardium, ProBNP-108, a BNP precursor, undergoes glycosylation, after which a portion is cleaved by furin into mature BNP-32 and N-terminal proBNP-76, depending on the glycosylation status. As a result, active BNP, less active proBNP, and inactive N-terminal proBNP all circulate in the blood. There are three major pathways for BNP clearance: (1) cellular internalization via natriuretic peptide receptor (NPR)-A and NPR-C; (2) degradation by proteases in the blood, including neprilysin, dipeptidyl-peptidase-IV, insulin degrading enzyme, etc.; and (3) excretion in the urine. Because neprilysin has lower substrate specificity for BNP than atrial natriuretic peptide (ANP), the increase in plasma BNP after angiotensin receptor neprilysin inhibitor (ARNI) administration is much smaller than the increase in plasma ANP. Currently available BNP immunoassays react with both mature BNP and proBNP. Therefore, BNP measured with an immunoassay is mature BNP + proBNP. ARNI administration increases mature BNP but not proBNP, as the latter is not degraded by neprilysin. Consequently, measured plasma BNP initially increases with ARNI administration by the amount of the increase in mature BNP. Later, ARNI reduces myocardial wall stress, and the resultant reduction in BNP production more than offsets the increase in mature BNP mediated by inhibiting degradation by neprilysin, which lowers plasma BNP levels. These results suggest that even in the ARNI era, BNP can be used for diagnosis and assessment of the pathophysiology and prognosis of heart failure, though the mild increases early during ARNI administration should be taken into consideration.

Small extracellular vesicles derived from patients with persistent atrial fibrillation exacerbate arrhythmogenesis via miR-30a-5p

Small extracellular vesicles (sEVs) are nanometer-sized membranous vesicles that contribute to the pathogenesis of atrial fibrillation (AF). Here, we investigated the role of sEVs derived from patients with persistent AF in the pathophysiology of AF. First, we evaluated the pathological effects of sEVs derived from the peripheral blood of patients with persistent AF (AF-sEVs). AF-sEVs treatment reduced cell viability, caused abnormal Ca2+ handling, induced reactive oxygen species (ROS) production, and led to increased CaMKII activation of non-paced and paced atrial cardiomyocytes. Next, we analyzed the miRNA profile of AF-sEVs to investigate which components of AF-sEVs promote arrhythmias, and we selected six miRNAs that correlated with CaMKII activation. qRT-PCR experiment identified that miR-30a-5p was significantly downregulated in AF-sEVs, paced cardiomyocytes, and atrial tissues of patients with persistent AF. CaMKII was predicted by bioinformatics analysis as a miR-30a-5p target gene and validated by a dual luciferase reporter; hence, we evaluated the effects of miR-30a-5p on paced cardiomyocytes and validated miR-30a-5p as a pro-arrhythmic signature of AF-sEVs. Consequently, AF-sEVs-loaded with miR-30a-5p attenuated pacing-induced Ca2+-handling abnormalities, whereas AF-sEVs-loaded with anti-miR-30a-5p reversed the change in paced cardiomyocytes. Taken together, the regulation of CaMKII by miR-30a-5p revealed that miR-30a-5p is a major mediator for AF-sEVs-mediated AF pathogenesis. Accordingly, these findings suggest that sEVs derived from patients with persistent AF exacerbate arrhythmogenesis via miR-30a-5p.

A new biomarker of cardiac resynchronization therapy response: cGMP to mature BNP ratio

BACKGROUND

Biomarkers that can predict cardiac resynchronization therapy (CRT) response have not yet been identified. The purpose of this study was to assess whether individual measurements of four brain/B-type natriuretic peptide (BNP) forms, coupled with cyclic guanosine monophosphate (cGMP) might contribute to the prediction of echocardiographic CRT responders.

METHODS

A BNP precursor (proBNP) and total BNP (= proBNP + mature BNP) were measured with newly developed kits, while an N-terminal fragment of proBNP (NT-proBNP) and cGMP were measured with commercial kits on the day before CRT implantation. Estimated mature BNP (emBNP = total BNP-proBNP), and the ratio of cGMP to each BNP form, as well as the concentrations of three other BNP forms, were prospectively investigated for their capability in predicting a response to CRT. A CRT responder was defined as an improvement in left ventricular ejection fraction >10% and/or a reduction in left ventricular end-systolic volume >15% at 6-month follow-up.

RESULTS

Out of 77 patients, 46 (60%) were categorized as CRT responders. Among the measurement parameters, only the highest quartile of the cGMP to emBNP ratio was an independent predictor of CRT responders (odds ratio 4.87, 95% confidence interval 1.25-18.89, p = 0.02). The cGMP to emBNP ratio was associated with the cumulative events of heart failure hospitalization within one year following CRT implantation (log-rank p = 0.029).

CONCLUSIONS

The cGMP to emBNP ratio could be utilized as a predictive biomarker of CRT responders. (Clinical Study on Responder Prediction in Cardiac Resynchronization Therapy Using Individual Molecular Measurement of Natriuretic Peptide: UMIN R000038927).

miR-30b-5p inhibits proliferation, invasion, and migration of papillary thyroid cancer by targeting GALNT7 via the EGFR/PI3K/AKT pathway

BACKGROUND

Papillary thyroid carcinoma (PTC) is a common endocrine tumor. Increasing evidence has shown that microRNA dysfunction is involved in the occurrence and development of cancer. The expression of MicroRNA-30b-5p (miR-30b-5p) was down-regulated in PTC; however, its role in the development of PTC is not clear. Hence, this study aimed to explore the role and mechanism of miR-30b-5p in the occurrence and development of PTC.

METHODS

The qRT-PCR assay was used to detect the expression of miR-30b-5p in 60 cases of papillary thyroid carcinoma along with their matched non-cancerous tissues. This study explored the biological function of miR-30b-5p by the functional gain and loss experiments in vitro and vivo. The direct target gene of miR-30b-5p and its signaling pathway was identified through bioinformatics analysis, qRT-PCR, western blot, rescue experiments, and double luciferase 3'-UTR report analysis.

RESULTS

This study demonstrated that the low expression of miR-30b-5p is related to poor clinicopathological features. Functionally, the overexpression of miR-30b-5p inhibited the proliferation, invasion, and migration of PTC cells. Bioinformatics and luciferase analysis showed that GALNT7 is the direct and functional target of miR-30b-5p. Moreover, miR-30b-5p inhibited the proliferation of PTC in vivo by inhibiting the expression of GALNT7. The studies on the mechanism have shown that GALNT7 promotes cell proliferation and invasion by activating EGFR/PI3K/AKT kinase pathway, which can be attenuated by the kinase inhibitors.

CONCLUSIONS

Overall, miR-30b-5p inhibited the progression of papillary thyroid carcinoma by targeting GALNT7 and inhibiting the EGFR/PI3K/AKT pathway.

Molecular ratio of mature B-type natriuretic peptide in acute heart failure: an indicator for ventricular contractile recovery

Aims

The methodology to distinguish between the heart failure (HF) with recovered ejection fraction (HFrecEF) and those with continuously reduced ejection fraction (EF) (HFcrEF) on admission has not been established. We recently demonstrated that the ratio of plasma levels of pro‐B‐type natriuretic peptide (proBNP) to total BNP (proBNP plus mature BNP) is decreased on admission in patients with mild acute HF, but not in severe acute HF as a compensatory mechanism for activating cyclic GMP via increases of bioactive mature BNP. We aimed to test the hypothesis that the ratio of bioactive mature BNP to total BNP is associated with reverse remodelling capacity in patients with HF with reduced EF.

Methods and results

Plasma proBNP and total BNP were measured in patients with acute decompensated HF by using specific and sensitive enzyme immunochemiluminescent assay. Estimated percent mature BNP (%emBNP) was calculated as ([total BNP − proBNP]/total BNP) × 100. We retrospectively identified the patients with reduced EF (≤40%, on admission) who had echocardiographic data after discharge (n = 93). We defined patients with increased EF by >10% during the follow‐up term (median, 545 days) after the admission as HFrecEF group. We compared patient characteristics, %emBNP, and other biomarkers between HFrecEF and HFcrEF. Of the enrolled patients with HFrecEF (n = 32) and HFcrEF (n = 61), on admission, %emBNP was significantly higher in HFrecEF than in HFcrEF (44.1% vs. 36.9%; P < 0.05). There were no significant differences in left ventricular EF on admission between the two groups. The univariate analysis revealed that %emBNP on admission was associated with HFrecEF occurrence rate (P < 0.05), in contrast both total BNP and high‐sensitive cardiac troponin‐T levels were not associated with HFrecEF occurrence rate.

Conclusions

The ratio of mature BNP to total BNP in plasma at the time of hospital admission may be predictive of left ventricular contractile recovery. Preservation of the capacity to convert proBNP to mature BNP, but not myocardial injury itself, is associated with future ventricular contractile recovery.

Toward a New Paradigm for Targeted Natriuretic Peptide Enhancement in Heart Failure

The natriuretic peptide system (NPS) plays a fundamental role in maintaining cardiorenal homeostasis, and its potent filling pressure-regulated diuretic and vasodilatory effects constitute a beneficial compensatory mechanism in heart failure (HF). Leveraging the NPS for therapeutic benefit in HF has been the subject of intense investigation during the last three decades and has ultimately reached widespread clinical use in the form of angiotensin receptor-neprilysin inhibition (ARNi). NPS enhancement via ARNi confers beneficial effects on mortality and hospitalization in HF, but inhibition of neprilysin leads to the accumulation of a number of other vasoactive peptides in the circulation, often resulting in hypotension and raising potential concerns over long-term adverse effects. Moreover, ARNi is less effective in the large group of HF patients with preserved ejection fraction. Alternative approaches for therapeutic augmentation of the NPS with increased specificity and efficacy are therefore warranted, and are now becoming feasible particularly with recent development of RNA therapeutics. In this review, the current state-of-the-art in terms of experimental and clinical strategies for NPS augmentation and their implementation will be reviewed and discussed.

Global functions of O-glycosylation: promises and challenges in O-glycobiology

Mucin type O-glycosylation is one of the most diverse types of glycosylation, playing essential roles in tissue development and homeostasis. In complex organisms, O-GalNAc glycans comprise a substantial proportion of the glycocalyx, with defined functions in hemostatic, gastrointestinal, and respiratory systems. Furthermore, O-GalNAc glycans are important players in host-microbe interactions, and changes in O-glycan composition are associated with certain diseases and metabolic conditions, which in some instances can be used for diagnosis or therapeutic intervention. Breakthroughs in O-glycobiology have gone hand in hand with the development of new technologies, such as advancements in mass spectrometry, as well as facilitation of genetic engineering in mammalian cell lines. High-throughput O-glycoproteomics have enabled us to draw a comprehensive map of O-glycosylation, and mining this information has supported the definition and confirmation of functions related to site-specific O-glycans. This includes protection from proteolytic cleavage, as well as modulation of binding affinity or receptor function. Yet, there is still much to discover, and among the important next challenges will be to define the context-dependent functions of O-glycans in different stages of cellular differentiation, cellular metabolism, host-microbiome interactions, and in disease. In this review, we present the achievements and the promises in O-GalNAc glycobiology driven by technological advances in analytical methods, genetic engineering, and systems biology.

Potential pitfalls when interpreting plasma BNP levels in heart failure practice

B-type (or brain) natriuretic peptide (BNP) is synthesized in cardiac myocytes and released constitutively into the circulation. Pressure/volume overload, neurohumoral factors, cytokines, and ischemia enhance BNP gene expression, and then precursor proBNP is produced. It has been thought that proBNP is cleaved into active BNP molecule and inactive marker molecule NT-proBNP intracellularly by processing enzyme furin, and they are released into the circulation. However, recent studies have shown that considerable amount of uncleaved proBNP circulates in the blood. The commercially available BNP assay kits consist of two antibodies that sandwich the BNP molecule. Therefore, if proBNP is present, BNP assay kit cross-reacts to proBNP and measures it as BNP. Therefore, it should be noted that the current BNP value is proBNP plus BNP. BNP and NT-proBNP have been established as a biomarker for heart failure patients presenting dyspnea. But many pitfalls are present for interpreting the BNP value. For example, the presence of renal dysfunction, age, female sex, atrial fibrillation, inflammation, hyperthyroidism, use of sacubitril/valsartan, and macro-proBNPemia overestimate BNP value, whereas the presence of obesity, immediately after acute coronary syndrome onset, and pericardial effusion underestimate BNP value. In the management for heart failure patients, BNP plays an important role. Therefore, clinicians should note the pitfall of interpretation of BNP and we describe the mechanism involved.

Elevation of Plasminogen Activator Inhibitor-1 promotes differentiation of Cancer Stem-like Cell state by Hepatitis C Virus infection

Plasminogen activator inhibitor-1 (PAI-1) is a critical factor that regulates protein synthesis and degradation. The increased PAI-1 levels are detectable in the serum of patients with chronic hepatitis C virus (HCV) liver disease. The differentiation state and motility of HCV-induced cancer stem-like cells (CSC) play a major role in severe liver disease progression. However, the role of PAI-1 in the pathological process of chronic liver diseases remains unknown. In this study, we determined how PAI-1 affects the differentiation of CSC state in hepatocytes upon HCV infection. We found that HCV infection induced the expression of PAI-1 while decreasing miR-30c expression in Huh7.5.1 cells. Similar results were obtained from isolated hepatocytes from humanized liver mice after HCV infection. Moreover, decreased miR-30c expression in HCV-infected hepatocytes was associated with the increased levels of PAI-1 mRNA and protein. Notably, the increased PAI-1 levels resulted in the activation of Protein Kinase B/AKT, a major mediator of cell proliferation, in HCV-infected hepatocytes along with the increased expression of CSC markers such as Human Differentiated Protein (CD) 133, Epithelial cell adhesion molecule (EpCAM), Octamer 4 (Oct4), Nanog, Cyclin D1, and MYC. Moreover, blockade of PAI-1 activity by miR-30c mimic and anti-PAI-1 mAb abrogated the AKT activation with decreased expression of CSC markers. Our findings suggest that HCV infection induces the CSC state via PAI-1-mediated AKT activation in hepatocytes. It implicates that the manipulation of PAI-1 activity could provide potential therapeutics to prevent the development of HCV-associated chronic liver diseases.IMPORTANCEThe progression of chronic liver disease by HCV infection is considered a major risk factor for hepatocellular carcinoma (HCC), one of the major causes of death from cancer. Recent studies have demonstrated that increased CSC properties in HCV-infected hepatocytes are associated with the progression of HCC. Since proteins and miRNAs production by HCV-infected hepatocytes can play various roles in physiological processes, investigating these factors can potentially lead to new therapeutic targets. However, the mechanism of HCV associated progression of hepatocytes to CSC remains unclear. Here we identify the roles of PAI-1 and miR-30c in the progression of CSC during HCV infection in hepatocytes. Our data shows that increased secretion of PAI-1 following HCV infection promotes this CSC state and activation of AKT. We report that the inhibition of PAI-1 by miR-30c mimic reduces HCV associated CSC properties in hepatocytes. Taken together, targeting this interaction of secreted PAI-1 and miR-30c in HCV-infected hepatocytes may provide a potential therapeutic intervention against the progression to chronic liver diseases and HCC.

The natriuretic peptide system in heart failure: Diagnostic and therapeutic implications

Natriuretic peptides, which are activated in heart failure, play an important cardioprotective role. The most notable of the cardioprotective natriuretic peptides are atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), which are abundantly expressed and secreted in the atrium and ventricles, respectively, and C-type natriuretic peptide (CNP), which is expressed mainly in the vasculature, central nervous system, and bone. ANP and BNP exhibit antagonistic effects against angiotensin II via diuretic/natriuretic actions, vasodilatory actions, and inhibition of aldosterone secretion, whereas CNP is involved in the regulation of vascular tone and blood pressure, among other roles. ANP and BNP are of particular interest with respect to heart failure, as their levels, most notably BNP and N-terminal proBNP-a cleavage product produced when proBNP is processed to mature BNP-are increased in patients with heart failure. Furthermore, the identification of natriuretic peptides as sensitive markers of cardiac load has driven significant research into their physiological roles in cardiovascular homeostasis and disease, as well as their potential use as both biomarkers and therapeutics. In this review, I discuss the physiological functions of the natriuretic peptide family, with a particular focus on the basic research that has led to our current understanding of its roles in maintaining cardiovascular homeostasis, and the pathophysiological implications for the onset and progression of heart failure. The clinical significance and potential of natriuretic peptides as diagnostic and/or therapeutic agents are also discussed.

Exposing the High Heterogeneity of Circulating Pro B-Type Natriuretic Peptide Fragments in Healthy Individuals and Heart Failure Patients

BACKGROUND

The high molecular complexity of variably O-glycosylated and degraded pro B-type natriuretic peptide (proBNP) derived molecular forms challenges current immunoassays. Antibodies used show pronounced differences in cross-reactivities with these circulating fragments, which still need to be better characterized on a molecular level. To pave the way for advanced quantitative assays in the future, it is critical to fully understand these circulating forms.

METHODS

Plasma samples were collected from 8 heart failure (HF) patients and 2 healthy controls. NT-proBNP and proBNP were purified by immunoprecipitation and analyzed by nano-flow liquid chromatography coupled to high-resolution mass spectrometry. Fragments formed during proteolysis in solution digestion were distinguished from naturally occurring peptides by using an 18O stable isotope labeling strategy.

RESULTS

We detected 16 previously unknown circulating fragments of proBNP peptides (9 of which are located in the N-terminal and 7 in the C-terminal region), revealing a more advanced state of degradation than previously known. Two of these fragments are indicative of either unidentified processing modes or a far-reaching C-terminal degradation (or a combination thereof) of the precursor proBNP.

CONCLUSIONS

Our results further restrict ideal target epitopes for immunoassay antibodies and expand the current thinking of diversity, degradation, and processing of proBNP, as well as the distribution of circulating forms.

Single-Cell Transcriptome Analysis Decipher New Potential Regulation Mechanism of ACE2 and NPs Signaling Among Heart Failure Patients Infected With SARS-CoV-2

Aims: COVID-19 patients with comorbidities such as hypertension or heart failure (HF) are associated with poor clinical outcomes. The cellular distribution of Angiotensin-converting enzyme 2 (ACE2), the critical enzyme for SARS-CoV-2 infection, in the human heart is unknown. We explore the underlying mechanism that leads to increased susceptibility to SARS-CoV-2 in patients with cardiovascular diseases and patients of cardiac dysfunction have increased risk of multi-organ injury compared with patients of normal cardiac function.

Methods and Results: We analyzed single-cell RNA sequencing (scRNA-seq) data in both normal and failing hearts. The results demonstrated that ACE2 is present in cardiomyocytes (CMs) and non-CMs, while the number of ACE2-postive (ACE2+) CMs and ACE2 gene expression in these CMs are significantly increased in the failing hearts. Interestingly, both brain natriuretic peptides (BNP) and atrial natriuretic peptide (ANP) are significantly up-regulated in the ACE2+ CMs, which is consistent with other studies that ACE2, ANP, and BNP increased in HF patients. We found that genes related to virus entry, virus replication and suppression of interferon-gamma signaling are all up-regulated in failing CMs, and the increase was significantly higher in ACE2+ CMs, suggesting that these CMs may be more vulnerable to virus infection. As the level of expression of both ACE2 and BNP in CMs were up-regulated, we further performed retrospective analysis of the plasma BNP levels and clinical outcomes of 91 COVID-19 patients from a single-center. Patients with higher plasma BNP were associated with significantly higher mortality and expression levels of inflammatory and infective markers.

Conclusion: In the failing heart, the upregulation of ACE2 and virus infection associated genes could potentially facilitate SARS-CoV-2 virus entry and replication in these vulnerable cardiomyocyte subsets. COVID-19 patients with higher plasma BNP levels had poorer clinical outcomes. These observations may allude to a potential regulatory association between ACE2 and BNP in mediating myocarditis associated with COVID-19.

Mucin-Type O-GalNAc Glycosylation in Health and Disease

Mucin-type GalNAc O-glycosylation is one of the most abundant and unique post-translational modifications. The combination of proteome-wide mapping of GalNAc O-glycosylation sites and genetic studies with knockout animals and genome-wide analyses in humans have been instrumental in our understanding of GalNAc O-glycosylation. Combined, such studies have revealed well-defined functions of O-glycans at single sites in proteins, including the regulation of pro-protein processing and proteolytic cleavage, as well as modulation of receptor functions and ligand binding. In addition to isolated O-glycans, multiple clustered O-glycans have an important function in mammalian biology by providing structural support and stability of mucins essential for protecting our inner epithelial surfaces, especially in the airways and gastrointestinal tract. Here the many O-glycans also provide binding sites for both endogenous and pathogen-derived carbohydrate-binding proteins regulating critical developmental programs and helping maintain epithelial homeostasis with commensal organisms. Finally, O-glycan changes have been identified in several diseases, most notably in cancer and inflammation, where the disease-specific changes can be used for glycan-targeted therapies. This chapter will review the biosynthesis, the biology, and the translational perspectives of GalNAc O-glycans.

Epigenetic control of natriuretic peptides: implications for health and disease

The natriuretic peptides (NPs) family, including a class of hormones and their receptors, is largely known for its beneficial effects within the cardiovascular system to preserve regular functions and health. The concentration level of each component of the family is of crucial importance to guarantee a proper control of both systemic and local cardiovascular functions. A fine equilibrium between gene expression, protein secretion and clearance is needed to achieve the final optimal level of NPs. To this aim, the regulation of gene expression and translation plays a key role. In this regard, we know the existence of fine regulatory mechanisms, the so-called epigenetic mechanisms, which target many genes at either the promoter or the 3'UTR region to inhibit or activate their expression. The gene encoding ANP (NPPA) is regulated by histone modifications, DNA methylation, distinct microRNAs and a natural antisense transcript (NPPA-AS1) with consequent implications for both health and disease conditions. Notably, ANP modulates microRNAs on its own. Histone modifications of BNP gene (NPPB) are associated with several cardiomyopathies. The proBNP processing is regulated by miR30-GALNT1/2 axis. Among other components of the NPs family, CORIN, NPRA, NPRC and NEP may undergo epigenetic regulation. A better understanding of the epigenetic control of the NPs family will allow to gain more insights on the pathological basis of common cardiovascular diseases and to identify novel therapeutic targets. The present review article aims to discuss the major achievements obtained so far with studies on the epigenetic modulation of the NPs family.

BNP and NT-proBNP Interpretation in the Neprilysin Inhibitor Era

PURPOSE OF REVIEW

Describe the mechanisms that may influence change in measured natriuretic peptide levels when using the neprilysin inhibitor sacubitril to treat a patient with heart failure.

RECENT FINDINGS

Prior to the introduction of the neprilysin inhibitor sacubitril as part of a chemical combination with the angiotensin receptor blocker valsartan shown to reduce mortality and heart failure hospitalizations in patients with heart failure with reduced ejection fraction, the natriuretic peptide assays for B-type natriuretic peptide (BNP) and the amino-terminal proBNP (NT-proBNP) assays were shown to have similar diagnostic accuracy to differentiate heart failure from other etiologies of shortness of breath. Sacubitril/valsartan use has been shown to result in a modest and chronic elevation of BNP while reducing levels of NT-prBNP. This review explores the potential impact of these findings on interpreting natriuretic peptide results for diagnosis and prognosis, as well as explore the challenges associated with the heterogeneity of this finding, highlighting the impact of inhibiting neprilysin, a non-specific endopeptidase with multiple target sites within BNP and other proteins. With increased uptake of sacubitril/valsartan expected in patients with heart failure, interpretation of natriuretic peptide assays becomes somewhat more complex, particularly for BNP. However, knowing a baseline steady-state concentration and using the same assay can assist with BNP interpretation for diagnosis and prognosis.

Sweet Control: MicroRNA Regulation of the Glycome

Glycosylation is a sophisticated informational system that controls specific biological functions at the cellular and organismal level. Dysregulation of glycosylation may underlie some of the most complex and common diseases of the modern era. In the past 5 years, microRNAs have come to the forefront as a critical regulator of the glycome. Herein, we review the current literature on miRNA regulation of glycosylation and how this work may point to a new way to identify the biological importance of glycosylation enzymes.

The therapeutic effect of B-type natriuretic peptides in acute decompensated heart failure

B-type natriuretic peptide (BNP) exhibits roles in natriuresis and diuresis, making it an ideal drug that may aid in diuresing a fluid-overloaded patient with poor or worsening renal function. Several randomized clinical trials have tested the hypothesis that infusions of pharmacological doses of BNP to acute heart failure (HF) patients may enhance decongestion and preserve renal function in this clinical setting. Unfortunately, none of these have demonstrated beneficial outcomes. The current challenge for BNP research in acute HF lies in addressing a failure of concept and a reluctance to abandon an ineffective research model. Future success will necessitate a detailed understanding of the mechanism of action of BNP, as well as better integration of basic and clinical science.

The Importance of Natriuretic Peptides in Cardiometabolic Diseases

The natriuretic peptide (NP) system is composed of 3 distinct peptides (atrial natriuretic peptide or ANP, B-type natriuretic peptide or BNP, and C-type natriuretic peptide or CNP) and 3 receptors (natriuretic peptide receptor-A or NPR-A or particulate guanynyl cyclase-A natriuretic peptide receptor-B or NPR-B or particulate guanynyl cyclase-B, and natriuretic peptide receptor-C or NPR-C or clearance receptor). ANP and BNP function as defense mechanisms against ventricular stress and the deleterious effects of volume and pressure overload on the heart. Although the role of NPs in cardiovascular homeostasis has been extensively studied and well established, much remains uncertain about the signaling pathways in pathological states like heart failure, a state of impaired natriuretic peptide function. Elevated levels of ANP and BNP in heart failure correlate with disease severity and have a prognostic value. Synthetic ANP and BNP have been studied for their therapeutic role in hypertension and heart failure, and promising trials are under way. In recent years, the expression of ANP and BNP in human adipocytes has come to light. Through their role in promotion of adipocyte browning, lipolysis, lipid oxidation, and modulation of adipokine secretion, they have emerged as key regulators of energy consumption and metabolism. NPR-A signaling in skeletal muscles and adipocytes is emerging as pivotal to the maintenance of long-term insulin sensitivity, which is disrupted in obesity and reduced glucose-tolerance states. Genetic variants in the genes encoding for ANP and BNP have been associated with a favorable cardiometabolic profile. In this review, we discuss several pathways that have been proposed to explain the role of NPs as endocrine networkers. There is much to be explored about the therapeutic role of NPs in improving metabolic milieu.

Single-cell Transcriptome Analysis Indicates New Potential Regulation Mechanism of ACE2 and NPs signaling among heart failure patients infected with SARS-CoV-2

BACKGROUND

COVID-19 patients with comorbidities such as hypertension or heart failure (HF) are associated with poor clinical outcomes. Angiotensin-converting enzyme 2 (ACE2), the critical enzyme for SARS-CoV-2 infection, is broadly expressed in many organs including heart. However, the cellular distribution of ACE2 in the human heart, particularly the failing heart is unknown.

METHODS

We analyzed single-cell RNA sequencing (scRNA-seq) data in both normal and failing hearts, and characterized the ACE2 gene expression profile in various cell subsets, especially in cardiomyocyte subsets, as well as its interaction with gene networks relating to various defense and immune responses at the single cell level.

RESULTS

The results demonstrated that ACE2 is present in cardiomyocytes (CMs), endothelial cells, fibroblasts and smooth muscle cells in the heart, while the number of ACE2-postive (ACE2+) CMs and ACE2 gene expression in these CMs are significantly increased in the failing hearts. Interestingly, both brain natriuretic peptides (BNP) and atrial natriuretic peptide (ANP) are significantly up-regulated in the ACE2+ CMs. Further analysis shows that ANP, BNP and ACE2 may form a negative feedback loop with a group of genes associated with the development of heart failure. To our surprise, we found that genes related to virus entry, virus replication and suppression of interferon-gamma（IFN-γ）signaling are all up-regulated in CMs in failing hearts, and the increases were significantly higher in ACE2+ CMs as compared with ACE2 negative (ACE2-) CMs, suggesting that these ACE2+ CMs may be more vulnerable to virus infection. Since ACE2 expression is correlated with BNP expression, we further performed retrospective analysis of the plasma BNP levels and clinic outcome of 91 COVID-19 patients from a single-center. Patients with higher plasma BNP were associated with significantly higher mortality rate and expression levels of inflammatory and infective markers such as procalcitonin and C-reactive protein.

CONCLUSION

In the failing heart, the upregulation of ACE2 and virus infection associated genes, as well as the increased expression of ANP and BNP could facilitate SARS-CoV-2 virus entry and replication in these vulnerable cardiomyocyte subsets. These findings may advance our understanding of the underlying molecular mechanisms of myocarditis associated with COVID-19.

Sweet rescue or surrender of the failing heart?

Natriuretic peptides (NPs) are hormones involved in maintaining heart health that undergo proteolytic cleavage to become activated. Previous work has shown that O-GalNAc glycans affect their processing and activation. Here, Goetze, Schjoldager, and colleagues now provide comprehensive characterization of O-glycosylation of NPs, revealing that all members of the NP family can be modified by O-GalNAc glycans. Intriguingly, the study discovers glycans in the receptor-binding region of the A-type natriuretic peptide (ANP), demonstrating that they affect both stability and activity of ANP. These results may inform future therapeutic approaches for heart failure using peptide glycoforms.

Change in the NT-proBNP/Mature BNP Molar Ratio Precedes Worsening Renal Function in Patients With Acute Heart Failure: A Novel Predictor Candidate for Cardiorenal Syndrome

Background Early detection for worsening renal function (WRF) is indispensable in patients with acute decompensated heart failure (HF). We tested the hypothesis that the difference in the circulating levels of each B-type or brain natriuretic peptide (BNP) molecular form is associated with the occurrence of WRF. Methods and Results Circulating levels of proBNP, the NT-proBNP (N-terminal proBNP), and total BNP (proBNP+mature BNP) were prospectively measured in patients with acute decompensated HF using specific and sensitive enzyme immunochemiluminescent assays. An estimated mature BNP (emBNP) concentration was calculated by subtracting proBNP levels from total BNP levels. WRF was defined as a >20% decrease in the estimated glomerular filtration rate during the hospitalization. One-way repeated-measures ANOVA was used to compare the changes of variables between the patients with and without WRF. In patients with acute decompensated HF (New York Heart Association class III-IV; 96%) hospitalized for HF, NT-proBNP levels did not differ during the hospitalization between patients with and without WRF (n=42 and 140, respectively). By contrast, emBNP levels were lower in patients with WRF than in those without WRF on day 3 after admission. NT-proBNP/emBNP molar ratios were elevated on day 3 after admission in the patients with WRF, before estimated glomerular filtration rate declined, but were unchanged in patients without WRF. On day 3 after hospital admission, NT-proBNP/emBNP ratios were strongly associated with percentage decreases in estimated glomerular filtration rate. Conclusions These findings suggest that elevation of NT-proBNP/emBNP ratio precedes WRF in patients with acute HF and can be a potentially useful biomarker for risk stratification of cardiorenal syndrome.

The microRNA in ventricular remodeling: the miR-30 family

Ventricular remodeling (VR) is a complex pathological process of cardiomyocyte apoptosis, cardiac hypertrophy, and myocardial fibrosis, which is often caused by various cardiovascular diseases (CVDs) such as hypertension, acute myocardial infarction, heart failure (HF), etc. It is also an independent risk factor for a variety of CVDs, which will eventually to damage the heart function, promote cardiovascular events, and lead to an increase in mortality. MicroRNAs (miRNAs) can participate in a variety of CVDs through post-transcriptional regulation of target gene proteins. Among them, microRNA-30 (miR-30) is one of the most abundant miRNAs in the heart. In recent years, the study found that the miR-30 family can participate in VR through a variety of mechanisms, including autophagy, apoptosis, oxidative stress, and inflammation. VR is commonly found in ischemic heart disease (IHD), hypertensive heart disease (HHD), diabetic cardiomyopathy (DCM), antineoplastic drug cardiotoxicity (CTX), and other CVDs. Therefore, we will review the relevant mechanisms of the miR-30 in VR induced by various diseases.

Superiority of proatrial natriuretic peptide in the prognostic power in patients with acute decompensated heart failure on hospital admission: comparison with B-type natriuretic peptide and other natriuretic peptide forms

Aims

There are significant differences in how atrial (A-type) and B-type natriuretic peptide (ANP and BNP) are secreted and metabolised, but there is little information available about the relative clinical significance of the two peptides. The aim of the present study was to investigate: (1) the association between the circulating level of each ANP molecular form and patient clinical background and (2) their prognostic power for patients with acute decompensated heart failure (ADHF).

Methods

We used specific chemiluminescence enzyme immunoassays to prospectively evaluate the levels of six bioactive molecular forms of ANP (pro-ANP, β-ANP and total ANP) and BNP (pro-BNP, N-terminal pro-BNP (NT-pro-BNP) and total BNP) in plasma samples collected from 173 patients with ADHF on their hospital admission.

Results

We found that pro-ANP levels were strongly associated with left ventricular (LV) size and ejection fraction (p<0.001), but were not associated with left atrial size. Percent pro-ANP ([pro-ANP/total ANP]x100) was also associated with LV size and function. During the follow-up term (median: 469 days), composite adverse events (all causes of death or rehospitalisation for HF) occurred in 67 patients (38.7 %). Pro-ANP was significantly associated with composite adverse events even after adjusting by estimated glomerular filtration rate (eGFR) (p<0.05). In contrast, NT-pro-BNP was not independent of eGFR in the multivariate analysis.

Conclusion

Circulating levels of pro-ANP are strongly associated with LV function and clinical outcomes of patients with ADHF. These findings suggest that during the acute phases of HF, pro-ANP has a prognostic power comparable with NT-pro-BNP independently of renal function.

Discovery of O-glycans on atrial natriuretic peptide (ANP) that affect both its proteolytic degradation and potency at its cognate receptor

Atrial natriuretic peptide (ANP) is a peptide hormone that in response to atrial stretch is secreted from atrial myocytes into the circulation, where it stimulates vasodilatation and natriuresis. ANP is an important biomarker of heart failure where low plasma concentrations exclude cardiac dysfunction. ANP is a member of the natriuretic peptide (NP) family, which also includes the B-type natriuretic peptide (BNP) and the C-type natriuretic peptide. The proforms of these hormones undergo processing to mature peptides, and for proBNP, this process has previously been demonstrated to be regulated by O-glycosylation. It has been suggested that proANP also may undergo post-translational modifications. Here, we conducted a targeted O-glycoproteomics approach to characterize O-glycans on NPs and demonstrate that all NP members can carry O-glycans. We identified four O-glycosites in proANP in the porcine heart, and surprisingly, two of these were located on the mature bioactive ANP itself. We found that one of these glycans is located within a conserved sequence motif of the receptor-binding region, suggesting that O-glycans may serve a function beyond intracellular processing and maturation. We also identified an O-glycoform of proANP naturally occurring in human circulation. We demonstrated that site-specific O-glycosylation shields bioactive ANP from proteolytic degradation and modifies potency at its cognate receptor in vitro Furthermore, we showed that ANP O-glycosylation attenuates acute renal and cardiovascular ANP actions in vivo The discovery of novel glycosylated ANP proteoforms reported here significantly improves our understanding of cardiac endocrinology and provides important insight into the etiology of heart failure.

ProBNP That Is Not Glycosylated at Threonine 71 Is Decreased with Obesity in Patients with Heart Failure

BACKGROUND

Heart failure (HF) is a leading cause of morbidity and mortality worldwide. Plasma concentrations of B-type natriuretic peptide (BNP) or its amino terminal congener (NT-proBNP) are used for HF diagnosis and risk stratification. Because BNP concentrations are inexplicably lowered in obese patients, we investigated the relationship between proBNP glycosylation, plasma NT-proBNP, and body mass index (BMI) in HF patients.

METHODS

Three assays were developed to distinguish between total proBNP (glycosylated plus nonglycosylated proBNP), proBNP not glycosylated at threonine 71 (NG-T71), and proBNP not glycosylated in the central region (NG-C). Intraassay and interassay CVs were <15%; limits of detection were <21 ng/L; and samples diluted in parallel.

RESULT

Applying these assays and an NT-proBNP assay to plasma samples from 106 healthy volunteers and 238 HF patients determined that concentrations [median (interquartile range)] of proBNP, NG-T71, and NT-proBNP were greater in HF patients compared with controls [300 (44-664), 114 (18-254), and 179 (880-3459) ng/L vs 36 (18-229), 36 (18-175), and 40 (17-68) ng/L, respectively; all P < 0.012]. NG-C was undetectable in most samples. ProBNP concentrations in HF patients with BMI more or less than 30 kg/m² were not different (P = 0.85), whereas HF patients with BMI >30 kg/m² had lower NT-proBNP and NG-T71 concentrations (P < 0.003) and higher proBNP/NT-proBNP and proBNP/NG-T71 ratios (P = 0.001 and P = 0.02, respectively) than those with BMI <30 kg/m².

CONCLUSIONS

Increased BMI is associated with decreased concentrations of proBNP not glycosylated at T71. Decreased proBNP substrate amenable to processing could partially explain the lower NT-proBNP and BNP concentrations observed in obese individuals, including those presenting with HF.

Atrial and brain natriuretic peptides: Hormones secreted from the heart

The natriuretic peptide family consists of three biologically active peptides: atrial natriuretic peptide (ANP), brain (or B-type) natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). Among these, ANP and BNP are secreted by the heart and act as cardiac hormones. Both ANP and BNP preferentially bind to natriuretic peptide receptor-A (NPR-A or guanylyl cyslase-A) and exert similar effects through increases in intracellular cyclic guanosine monophosphate (cGMP) within target tissues. Expression and secretion of ANP and BNP are stimulated by various factors and are regulated via multiple signaling pathways. Human ANP has three molecular forms, α-ANP, β-ANP, and proANP (or γ-ANP), with proANP predominating in healthy atrial tissue. During secretion proANP is proteolytically processed by corin, resulting in secretion of bioactive α-ANP into the peripheral circulation. ProANP and β-ANP are minor forms in the circulation but are increased in patients with heart failure. The human BNP precursor proBNP is proteolytically processed to BNP_1-32 and N-terminal proBNP (NT-proBNP) within ventricular myocytes. Uncleaved proBNP as well as mature BNP_1-32 and NT-proBNP is secreted from the heart, and its secretion is increased in patients with heart failure. Mature BNP, its metabolites including BNP_3-32, BNP_4-32, and BNP_5-32, and proBNP are all detected as immunoreactive-BNP by the current BNP assay system. We recently developed an assay system that specifically detects human proBNP. Using this assay system, we observed that miR30-GALNTs-dependent O-glycosylation in the N-terminal region of proBNP contributes to regulation of the processing and secretion of proBNP from the heart.

Natriuretic peptides in human heart: Novel insight into their molecular forms, functions, and diagnostic use

Among the three natriuretic peptides, atrial/A-type natriuretic peptide (ANP) and brain/B-type natriuretic peptide (BNP) are primarily produced by, and secreted from, heart tissue. They maintain cardiovascular homeostasis by binding to natriuretic peptide receptor-A. Since plasma ANP and BNP concentrations, as well as expression, are elevated in response to increased body fluid volume and pressure load on the heart wall, these peptides are widely utilized as diagnostic biomarkers for evaluating heart failure. Regardless of their high utility, differences in their molecular forms between healthy and diseased subjects and how these relate to pathophysiology have not well been examined. Recent studies have shown that the circulating molecular forms of ANP and BNP are not uniform; bioactive α-ANP is the major ANP form, whereas the weakly active proBNP is the major BNP form. The relative ratios of the different molecular forms are altered under different pathophysiological conditions. These facts indicate that detailed measurements of each form may provide useful information on the pathophysiological state of heart tissue. Here, we revisit the relationship between the molecular forms of, and pathophysiological alterations in, human ANP and BNP and discuss the possible utility of the measurement of each of the molecular forms. The third peptide, C-type natriuretic peptide, activates natriuretic peptide receptor-B, but little is known about its production and function in the heart because of its extremely low levels. However, through recent studies, its role in the heart is gradually becoming clear. Here, we summarize its molecular forms, assay systems, and functions in the heart.

Translational science: Newly emerging science in biology and medicine - Lessons from translational research on the natriuretic peptide family and leptin

Translation is the process of turning observations in the laboratory, clinic, and community into interventions that improve the health of individuals and the public, ranging from diagnostics and therapeutics to medical procedures and behavioral changes. Translational research is defined as the effort to traverse a particular step of the translation process for a particular target or disease. Translational science is a newly emerging science, distinct from basic and clinical sciences in biology and medicine, and is a field of investigation focused on understanding the scientific and operational principles underlying each step of the translational process. Advances in translational science will increase the efficacy and safety of translational research in all diagnostic and therapeutic areas. This report examines translational research on novel hormones, the natriuretic peptide family and leptin, which have achieved clinical applications or for which studies are still ongoing, and also emphasizes the lessons that translational science has learned from more than 30 years' experience in translational research.

Amniotic Fluid Natriuretic Peptide Levels in Fetuses With Congenital Heart Defects or Arrhythmias

BACKGROUND

We have previously demonstrated that umbilical cord plasma natriuretic peptide (NP) levels reflect the severity of heart failure (HF) in fetuses with congenital heart defects (CHD). The aim of this study was to evaluate the significance of amniotic fluid (AF) NP levels in the assessment of HF in fetuses with CHD or arrhythmia.

METHODS AND RESULTS

This was a prospective observational study at a tertiary pediatric cardiac center. A total of 95 singletons with CHD or arrhythmia, and 96 controls from 2012 to 2015 were analyzed. AF concentrations of atrial NP (ANP), B-type NP (BNP) and N-terminal pro-B-type NP (NT-proBNP) at birth were compared with ultrasonographic assessment of fetal HF using the cardiovascular profile (CVP) score. Multivariate analysis showed that a CVP score ≤5 and preterm birth are independently associated with high AF NT-proBNP levels. AF NT-proBNP levels of fetuses with CHD or arrhythmia inversely correlated with CVP score (P for trend <0.01). In contrast, AF concentrations of ANP and BNP were extremely low, and it was difficult to assess the degree of fetal HF based on them.

CONCLUSIONS

AF NT-proBNP concentrations increase in stepwise fashion with the severity of HF in fetuses with CHD or arrhythmia; it was the optimal NP for assessing the fetal HF.

Cutting Edge of Brain Natriuretic Peptide (BNP) Research - The Diversity of BNP Immunoreactivity and Its Clinical Relevance

Brain (or B-type) natriuretic peptide (BNP) is a cardiac hormone produced in the heart and an established biochemical marker for heart failure (HF) because the level in plasma increases in proportion to disease severity. Recently, the diversity of BNP molecular forms in the peripheral circulation, which includes mature BNP (BNP_1-32) and its metabolites (BNP_3-32, BNP_4-32, and BNP_5-32), was demonstrated. Moreover, studies showed that unprocessed BNP prohormone (proBNP) is also secreted from the heart, and its secretion is increased in patients with HF. Interestingly, BNP_1-32, its metabolites, and proBNP are all detected as immunoreactive BNP by the currently available BNP assay system. Current N-terminal proBNP (NT-proBNP) assay systems also can react to both NT-proBNP and proBNP. In addition, the N-terminal region of proBNP and NT-proBNP are often O-glycosylated, which may result in underestimation of total NT-proBNP level, which includes both glycosylated and non-glycosylated NT-proBNP, by the NT-proBNP assay system. More recently, we have shown that miR30-GALNT-dependent O-glycosylation in the N-terminal region of proBNP affects the processing of proBNP and contributes to its secretion from the heart. The level of proBNP relative to BNP (proBNP/BNP ratio) in the coronary sinus is higher in patients with more severe HF. The proBNP/BNP ratio and the deglycosylated NT-proBNP level may be new and clinically useful biomarkers of HF.

miR-30 Family: A Promising Regulator in Development and Disease

MicroRNAs (miRNAs) are small noncoding RNAs that negatively regulate posttranscriptional expression of target genes. Accumulating evidences have demonstrated that the miR-30 family, as a member of microRNAs, played a crucial regulating role in the development of tissues and organs and the pathogenesis of clinical diseases, which indicated that it may be a promising regulator in development and disease. This review aims to clarify the current progress on the regulating role of miR-30 family in tissues and organs development and related disease and highlight their research prospective in the future.