Neuregulin-1 attenuates right ventricular diastolic stiffness in experimental pulmonary hypertension

Screening and identification of key biomarkers associated with endometriosis using bioinformatics and next-generation sequencing data analysis

Background

Endometriosis is a common cause of endometrial-type mucosa outside the uterine cavity with symptoms such as painful periods, chronic pelvic pain, pain with intercourse and infertility. However, the early diagnosis of endometriosis is still restricted. The purpose of this investigation is to identify and validate the key biomarkers of endometriosis.

Methods

Next-generation sequencing dataset GSE243039 was obtained from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between endometriosis and normal control samples were identified. After screening of DEGs, gene ontology (GO) and REACTOME pathway enrichment analyses were performed. Furthermore, a protein–protein interaction (PPI) network was constructed and modules were analyzed using the Human Integrated Protein–Protein Interaction rEference database and Cytoscape software, and hub genes were identified. Subsequently, a network between miRNAs and hub genes, and network between TFs and hub genes were constructed using the miRNet and NetworkAnalyst tool, and possible key miRNAs and TFs were predicted. Finally, receiver operating characteristic curve analysis was used to validate the hub genes.

Results

A total of 958 DEGs, including 479 upregulated genes and 479 downregulated genes, were screened between endometriosis and normal control samples. GO and REACTOME pathway enrichment analyses of the 958 DEGs showed that they were mainly involved in multicellular organismal process, developmental process, signaling by GPCR and muscle contraction. Further analysis of the PPI network and modules identified 10 hub genes, including vcam1, snca, prkcb, adrb2, foxq1, mdfi, actbl2, prkd1, dapk1 and actc1. Possible target miRNAs, including hsa-mir-3143 and hsa-mir-2110, and target TFs, including tcf3 (transcription factor 3) and clock (clock circadian regulator), were predicted by constructing a miRNA-hub gene regulatory network and TF-hub gene regulatory network.

Conclusions

This investigation used bioinformatics techniques to explore the potential and novel biomarkers. These biomarkers might provide new ideas and methods for the early diagnosis, treatment and monitoring of endometriosis.

Unraveling the Impact of miR-146a in Pulmonary Arterial Hypertension Pathophysiology and Right Ventricular Function

Pulmonary arterial hypertension (PAH) is a chronic disorder characterized by excessive pulmonary vascular remodeling, leading to elevated pulmonary vascular resistance and right ventricle (RV) overload and failure. MicroRNA-146a (miR-146a) promotes vascular smooth muscle cell proliferation and vascular neointimal hyperplasia, both hallmarks of PAH. This study aimed to investigate the effects of miR-146a through pharmacological or genetic inhibition on experimental PAH and RV pressure overload animal models. Additionally, we examined the overexpression of miR-146a on human pulmonary artery smooth muscle cells (hPASMCs). Here, we showed that miR-146a genic expression was increased in the lungs of patients with PAH and the plasma of monocrotaline (MCT) rats. Interestingly, genetic ablation of miR-146a improved RV hypertrophy and systolic pressures in Sugen 5415/hypoxia (SuHx) and pulmonary arterial banding (PAB) mice. Pharmacological inhibition of miR-146a improved RV remodeling in PAB-wild type mice and MCT rats, and enhanced exercise capacity in MCT rats. However, overexpression of miR-146a did not affect proliferation, migration, and apoptosis in control-hPASMCs. Our findings show that miR-146a may play a significant role in RV function and remodeling, representing a promising therapeutic target for RV hypertrophy and, consequently, PAH.

Compensatory role of neuregulin-1 in diabetic cardiomyopathy

Diabetes mellitus is a prevalent risk factor for congestive heart failure. Diabetic cardiomyopathy patients present with left ventricular (LV) diastolic dysfunction at an early stage, then systolic dysfunction as the disease progresses. The mechanism underlying the development of diabetic cardiomyopathy has not yet been fully understood. This study aimed to elucidate the mechanisms by which diastolic dysfunction precedes systolic dysfunction at the early stage of diabetic cardiomyopathy. We hypothesized that the downregulation of cardioprotective factors is involved in the pathogenesis of diabetic cardiomyopathy. LV diastolic dysfunction, but not systolic dysfunction, was observed in type-1 diabetes mellitus model mice 4 weeks after STZ administration (STZ-4W), mimicking the early stage of diabetic cardiomyopathy. Counter to expectations, neuregulin-1 (NRG1) was markedly upregulated in the vascular endothelial cell in the ventricles of STZ-4W mice. To clarify the functional significance of the upregulated NRG1, we blocked its receptor ErbB2 with trastuzumab (TRZ). In STZ-4W mice, TRZ significantly reduced the systolic function without affecting diastolic function and caused a more prominent reduction in Akt phosphorylation levels. These results indicate that the compensatory upregulated NRG1 contributes to maintaining the LV systolic function, which explains why diastolic dysfunction precedes systolic dysfunction at the early stage of diabetic cardiomyopathy.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

Bleomycin-induced lung injury: Revisiting an old tool to model group III PH associated with pulmonary fibrosis

Pulmonary hypertension (PH) is a chronic disorder of the pulmonary circulation that often associates with other respiratory diseases (i.e., group III PH), leading to worsened symptoms and prognosis, notably when combined with interstitial lung diseases such as pulmonary fibrosis (PF). PH may lead to right ventricular (RV) failure, which accounts for a substantial part of the mortality in chronic lung disease patients. The disappointing results of pulmonary arterial hypertension (PAH)-related therapies in patients with PF emphasize the need to better understand the pathophysiologic mechanisms that drive PH development and progression in this specific setting. In this work, we validated an animal model of group III PH associated with PF (PH-PF), by using bleomycin (BM) intratracheal instillation and characterizing the nature of induced lung and vascular remodeling, including the influence on RV structure and function. To our knowledge, this is the first work describing this dose of BM in Sprague Dawley rats and the effects upon the heart and lungs, using different techniques such as echocardiography, heart catheterization, and histology. Our data shows the successful implementation of a rat model that mimics combined PF-PH, with most features seen in the equivalent human disease, such as lung and arterial remodeling, increased mPAP and RV dysfunction.

Neuregulin-1, a potential therapeutic target for cardiac repair

NRG1 (Neuregulin-1) is an effective cardiomyocyte proliferator, secreted and released by endothelial vascular cells, and affects the cardiovascular system. It plays a major role in heart growth, proliferation, differentiation, apoptosis, and other cardiovascular processes. Numerous experiments have shown that NRG1 can repair the heart in the pathophysiology of atherosclerosis, myocardial infarction, ischemia reperfusion, heart failure, cardiomyopathy and other cardiovascular diseases. NRG1 can connect related signaling pathways through the NRG1/ErbB pathway, which form signal cascades to improve the myocardial microenvironment, such as regulating cardiac inflammation, oxidative stress, necrotic apoptosis. Here, we summarize recent research advances on the molecular mechanisms of NRG1, elucidate the contribution of NRG1 to cardiovascular disease, discuss therapeutic approaches targeting NRG1 associated with cardiovascular disease, and highlight areas for future research.

Neuregulin-1 enhances cell-cycle activity, delays cardiac fibrosis, and improves cardiac performance in rat pups with right ventricular pressure load

OBJECTIVES

Right ventricular (RV) failure is a leading cause of death in patients with congenital heart disease. RV failure is kept at bay during childhood. Limited proliferation of cardiomyocytes is present in the postnatal heart. We propose that cardiomyocyte proliferation improves RV adaptation to pressure load (PL). We studied adaptation in response to increased RV PL and the role of increased cardiomyocyte cell cycle activity (CCA) in rat pups growing into adulthood.

METHODS

We induced RV PL at day of weaning in rats (3 weeks; 30-40 g) by pulmonary artery banding and followed rats into adulthood (300 g). We performed histological analyses and RNA sequencing analysis. To study the effects of increased cardiomyocyte cell cycle activity, we administered neuregulin-1 (NRG1), a growth factor involved in cardiac development.

RESULTS

PL induced an increase in CCA, with subsequent decline of CCA (sham/PL at 4 weeks: 0.14%/0.83%; P = .04 and 8 weeks: 0.00%/0.00%; P = .484) and cardiac function (cardiac index: control/PL 4 weeks: 4.41/3.29; P = .468 and 8 weeks: 3.57/1.44; P = .024). RNA sequencing analysis revealed delayed maturation and increased CCA pathways. NRG1 stimulated CCA (PL vehicle/NRG1 at 2 weeks: 0.62%/2.28%; P = .003), improved cardiac function (cardiac index control vs vehicle/NRG1 at 2 weeks: 4.21 vs 3.07/4.17; P = .009/.705) and postponed fibrosis (control vs vehicle/NRG1 at 4 weeks: 1.66 vs 4.82%/2.97%; P = .009/.078) in RV PL rats during childhood.

CONCLUSIONS

RV PL during growth induces a transient CCA increase. Further CCA stimulation improves cardiac function and delays fibrosis. This proof-of-concept study shows that stimulation of CCA can improve RV adaptation to PL in the postnatal developing heart and might provide a new approach to preserve RV function in patients with congenital heart disease.

Exploring Functional Differences between the Right and Left Ventricles to Better Understand Right Ventricular Dysfunction

The right and left ventricles have traditionally been studied as individual entities. Furthermore, modifications found in diseased left ventricles are assumed to influence on right ventricle alterations, but the connection is poorly understood. In this review, we describe the differences between ventricles under physiological and pathological conditions. Understanding the mechanisms that differentiate both ventricles would facilitate a more effective use of therapeutics and broaden our knowledge of right ventricle (RV) dysfunction. RV failure is the strongest predictor of mortality in pulmonary arterial hypertension, but at present, there are no definitive therapies directly targeting RV failure. We further explore the current state of drugs and molecules that improve RV failure in experimental therapeutics and clinical trials to treat pulmonary arterial hypertension and provide evidence of their potential benefits in heart failure.

[Circulating Neuregulin-1 and Chronic Heart Failure with Preserved Ejection]

Chronic heart failure (CHF) with preserved ejection fraction (CHFpEF) is an unsolved, socially relevant challenge since it is associated with a high level of morbidity and mortality. Early markers for this pathology are unavailable, and therapeutic approaches are undeveloped. This necessitates extensive studying the mechanisms of CHFpEF to identify therapeutic targets. According to current notions, systemic inflammation and endothelial dysfunction play an important role in the pathogenesis of CHFpEF. These processes induce the development of myocardial fibrosis and impairment of cardiomyocyte relaxation, thereby resulting in diastolic dysfunction and increased left ventricular (LV) filling pressure. Neuregulin-1 (NRG-1) is a paracrine growth factor and a natural agonist of ErbB receptor family synthesized in the endothelium of coronary microvessels. The NRG-1 / ErbB4 system of the heart is activated at early stages of CHFpEF to enhance the cardiomyocyte resistance to oxidative stress. Preclinical and clinical (phases II and III) studies have shown that the recombinant NRG-1 therapy results in improvement of myocardial contractility and in LV reverse remodeling. Results of recent studies suggest possible anti-inflammatory and antifibrotic effects of NRG-1, which warrants studying the activity of this system in patients with CHFpEF.

Reviewing the Limitations of Adult Mammalian Cardiac Regeneration: Noncoding RNAs as Regulators of Cardiomyogenesis

The adult mammalian heart is incapable of regeneration following cardiac injury, leading to a decline in function and eventually heart failure. One of the most evident barriers limiting cardiac regeneration is the inability of cardiomyocytes to divide. It has recently become clear that the mammalian heart undergoes limited cardiomyocyte self-renewal throughout life and is even capable of modest regeneration early after birth. These exciting findings have awakened the goal to promote cardiomyogenesis of the human heart to repair cardiac injury or treat heart failure. We are still far from understanding why adult mammalian cardiomyocytes possess only a limited capacity to proliferate. Identifying the key regulators may help to progress towards such revolutionary therapy. Specific noncoding RNAs control cardiomyocyte division, including well explored microRNAs and more recently emerged long noncoding RNAs. Elucidating their function and molecular mechanisms during cardiomyogenesis is a prerequisite to advance towards therapeutic options for cardiac regeneration. In this review, we present an overview of the molecular basis of cardiac regeneration and describe current evidence implicating microRNAs and long noncoding RNAs in this process. Current limitations and future opportunities regarding how these regulatory mechanisms can be harnessed to study myocardial regeneration will be addressed.

Mechanisms of the Multitasking Endothelial Protein NRG-1 as a Compensatory Factor During Chronic Heart Failure

Heart failure is a complex syndrome whose phenotypic presentation and disease progression depends on a complex network of adaptive and maladaptive responses. One of these responses is the endothelial release of NRG (neuregulin)-1—a paracrine growth factor activating ErbB2 (erythroblastic leukemia viral oncogene homolog B2), ErbB3, and ErbB4 receptor tyrosine kinases on various targets cells. NRG-1 features a multitasking profile tuning regenerative, inflammatory, fibrotic, and metabolic processes. Here, we review the activities of NRG-1 on different cell types and organs and their implication for heart failure progression and its comorbidities. Although, in general, effects of NRG-1 in heart failure are compensatory and beneficial, translation into therapies remains unaccomplished both because of the complexity of the underlying pathways and because of the challenges in the development of therapeutics (proteins, peptides, small molecules, and RNA-based therapies) for tyrosine kinase receptors. Here, we give an overview of the complexity to be faced and how it may be tackled.