The emerging role of microRNAs in cardiac remodeling and heart failure.
ABSTRACT: Recent studies have suggested a potentially important role for a family of tiny regulatory RNAs, known as microRNAs (miRNAs or miRs), in the control of diverse aspects of cardiac function in health and disease. Although the field of miRNA biology is relatively new, there is emerging evidence that miRNAs may play an important role in the pathogenesis of heart failure through their ability to regulate the expression levels of genes that govern the process of adaptive and maladaptive cardiac remodeling. Here, we review the biology of miRNAs in relation to their role in modulating various aspects of the process of cardiac remodeling, as well as discuss the potential application of miRNA biology to the field of heart failure.
Project description:Like other organs, the heart undergoes normal adaptive remodeling, such as cardiac hypertrophy, with age. This remodeling, however, is intensified under stress and pathological conditions. Cardiac remodeling could be beneficial for a short period of time, to maintain a normal cardiac output in times of need; however, chronic cardiac hypertrophy may lead to heart failure and death. MicroRNAs (miRNAs) are known to have a role in the regulation of cardiac hypertrophy. This paper reviews recent advances in the field of miRNAs and cardiac hypertrophy, highlighting the latest findings for targeted genes and involved signaling pathways. By targeting pro-hypertrophic genes and signaling pathways, some of these miRNAs alleviate cardiac hypertrophy, while others enhance it. Therefore, miRNAs represent very promising potential pharmacotherapeutic targets for the management and treatment of cardiac hypertrophy.
Project description:Diastolic dysfunction in response to hypertrophy is a major clinical syndrome with few therapeutic options. MicroRNAs act as negative regulators of gene expression by inhibiting translation or promoting degradation of target mRNAs. Previously, we reported that genetic deletion of the cardiac-specific miR-208a prevents pathological cardiac remodeling and upregulation of Myh7 in response to pressure overload. Whether this miRNA might contribute to diastolic dysfunction or other forms of heart disease is currently unknown.Here, we show that systemic delivery of an antisense oligonucleotide induces potent and sustained silencing of miR-208a in the heart. Therapeutic inhibition of miR-208a by subcutaneous delivery of antimiR-208a during hypertension-induced heart failure in Dahl hypertensive rats dose-dependently prevents pathological myosin switching and cardiac remodeling while improving cardiac function, overall health, and survival. Transcriptional profiling indicates that antimiR-208a evokes prominent effects on cardiac gene expression; plasma analysis indicates significant changes in circulating levels of miRNAs on antimiR-208a treatment.These studies indicate the potential of oligonucleotide-based therapies for modulating cardiac miRNAs and validate miR-208 as a potent therapeutic target for the modulation of cardiac function and remodeling during heart disease progression.
Project description:Mechanical unloading by left ventricular assist devices (LVADs) in advanced heart failure (HF), in addition to improving symptoms and end-organ perfusion, is supposed to stimulate cellular and molecular responses which can reverse maladaptive cardiac remodeling. As microRNAs (miRNAs) are key regulators in remodeling processes, a comparative miRNA profiling in transplanted hearts of HF patients with/without LVAD assistance could aid to comprehend underlying molecular mechanisms. Next generation sequencing (NGS) was used to analyze miRNA differential expression in left ventricles of HF patients who underwent heart transplantation directly (n = 9) or following a period of LVAD support (n = 8). After data validation by quantitative real-time PCR, association with functional clinical parameters was investigated. Bioinformatics' tools were then used for prediction of putative targets of modulated miRNAs and relative pathway enrichment. The analysis revealed 13 upregulated and 10 downregulated miRNAs in failing hearts subjected to LVAD assistance. In particular, the expression level of some of them (miR-338-3p, miR-142-5p and -3p, miR-216a-5p, miR-223-3p, miR-27a-5p, and miR-378g) showed correlation with off-pump cardiac index values. Predicted targets of these miRNAs were involved in focal adhesion/integrin pathway and in actin cytoskeleton regulation. The identified miRNAs might contribute to molecular regulation of reverse remodeling and heart recovery mechanisms.
Project description:In response to stress, the heart undergoes extensive cardiac remodeling that results in cardiac fibrosis and pathological growth of cardiomyocytes (hypertrophy), which contribute to heart failure. Alterations in microRNA (miRNA) levels are associated with dysfunctional gene expression profiles associated with many cardiovascular disease conditions; however, miRNAs have emerged recently as paracrine signaling mediators. Thus, we investigated a potential paracrine miRNA crosstalk between cardiac fibroblasts and cardiomyocytes and found that cardiac fibroblasts secrete miRNA-enriched exosomes. Surprisingly, evaluation of the miRNA content of cardiac fibroblast-derived exosomes revealed a relatively high abundance of many miRNA passenger strands ("star" miRNAs), which normally undergo intracellular degradation. Using confocal imaging and coculture assays, we identified fibroblast exosomal-derived miR-21_3p (miR-21*) as a potent paracrine-acting RNA molecule that induces cardiomyocyte hypertrophy. Proteome profiling identified sorbin and SH3 domain-containing protein 2 (SORBS2) and PDZ and LIM domain 5 (PDLIM5) as miR-21* targets, and silencing SORBS2 or PDLIM5 in cardiomyocytes induced hypertrophy. Pharmacological inhibition of miR-21* in a mouse model of Ang II-induced cardiac hypertrophy attenuated pathology. These findings demonstrate that cardiac fibroblasts secrete star miRNA-enriched exosomes and identify fibroblast-derived miR-21* as a paracrine signaling mediator of cardiomyocyte hypertrophy that has potential as a therapeutic target.
Project description:During chronic heart failure, levels of circulating miRNAs endued with characteristics of diseased cells could be identified as biomarkers. In this study, we sought to identify cardiac-related circulating miRNAs as biomarkers of failing heart.Total RNA of plasma and heart samples was extracted from 10 normal controls and 14 patients with chronic heart failure. Microarray was applied for miRNA profiles. Validation and organ/tissue distribution analysis was performed by qRT-PCR. In addition, bioinformatics analysis was performed to understand the critical roles of these cardiac-related circulating miRNAs in heart failure.Results showed that levels of more than half of the miRNAs dysregulated in heart failed to show any differences in plasma. Meanwhile, more than 90% of the miRNAs dysregulated in plasma remained stable in heart. Four cardiac fibroblast-derived miRNAs (miR-660-3p, miR-665, miR-1285-3p and miR-4491) were found significantly upregulated in heart and plasma during heart failure. These 4 miRNAs strongly discriminated patients from controls, and 3 of them showed significant correlations with LVEF.This study provides global profiles of miRNAs changes in plasma and failing heart, and using a circulation-tissue miRNA profiling comparison model, we successfully identify 3 cardiac-related circulating miRNAs as potential biomarkers for diagnosis of heart failure.
Project description:Diverse forms of injury and stress evoke a hypertrophic growth response in adult cardiac myocytes, which is characterized by an increase in cell size, enhanced protein synthesis, assembly of sarcomeres, and reactivation of fetal genes, often culminating in heart failure and sudden death. Given the emerging roles of microRNAs (miRNAs) in modulation of cellular phenotypes, we searched for miRNAs that were regulated during cardiac hypertrophy and heart failure. We describe >12 miRNAs that are up- or down-regulated in cardiac tissue from mice in response to transverse aortic constriction or expression of activated calcineurin, stimuli that induce pathological cardiac remodeling. Many of these miRNAs were similarly regulated in failing human hearts. Forced overexpression of stress-inducible miRNAs was sufficient to induce hypertrophy in cultured cardiomyocytes. Similarly, cardiac overexpression of miR-195, which was up-regulated during cardiac hypertrophy, resulted in pathological cardiac growth and heart failure in transgenic mice. These findings reveal an important role for specific miRNAs in the control of hypertrophic growth and chamber remodeling of the heart in response to pathological signaling and point to miRNAs as potential therapeutic targets in heart disease.
Project description:Medical and device therapies that reduce heart failure morbidity and mortality also lead to decreased left ventricular volume and mass and a more normal elliptical shape of the ventricle. These are due to changes in myocyte size, structure, and organization that have been referred to collectively as reverse remodeling. Moreover, there are subsets of patients whose hearts have undergone reverse remodeling either spontaneously or after medical or device therapies and whose clinical course is associated with freedom from future heart failure events. This phenomenon has been referred to as myocardial recovery. Despite the frequent interchangeable use of the terms "myocardial recovery" and "reverse remodeling" to describe the reversal of various aspects of the heart failure phenotype after medical and device therapy, the literature suggests that there are important differences between these 2 phenomena and that myocardial recovery and reverse remodeling are not synonymous. In this review, we discuss the biology of cardiac remodeling, cardiac reverse remodeling, and myocardial recovery with the intent to provide a conceptual framework for understanding myocardial recovery.
Project description:Background:Cardiac hypertrophy is a well-known risk factor for heart failure and sudden cardiac death (SCD). On the other hand, physiological cardiac hypertrophy is often observed in young healthy men, and it is difficult to predict SCD in cardiac hypertrophy subjects who do not show symptoms of heart failure. MicroRNAs (miRNAs) widely regulate biological activity and play pivotal roles in heart failure progression. In this study, we investigated whether miRNA expression is altered in SCD with cardiac hypertrophy (SCH). Methods:Cardiac tissues were sampled at autopsy from SCH patients, compensated cardiac hypertrophy (CCH) subjects who died of causes other than heart failure, and control cases without cardiac hypertrophy or heart failure. After histopathological examination, we performed deep sequencing and quantitative PCR of cardiac miRNAs. Results and discussion:Although SCH and CCH showed indistinguishable histological features, their miRNA expression signatures were distinct. Among the 240 miRNAs stably detected in the heart, 8 were differentially expressed between SCH and CCH. Specifically, miR-221 increased in SCH compared to CCH and control cases. The significant elevation of cardiac miR-221 in SCH patients is correlated with lethal outcomes. Thus, our results indicate that an elevated miR-221 level is potentially associated with an increased risk of SCD in subjects with cardiac hypertrophy.
Project description:We recently identified a set of plasma microRNAs (miRNAs) that are downregulated in patients with heart failure in comparison with control subjects. To better understand their meaning and function, we sought to validate these circulating miRNAs in 3 different well-established rat and mouse heart failure models, and correlated the miRNAs to parameters of cardiac function.The previously identified let-7i-5p, miR-16-5p, miR-18a-5p, miR-26b-5p, miR-27a-3p, miR-30e-5p, miR-199a-3p, miR-223-3p, miR-423-3p, miR-423-5p and miR-652-3p were measured by means of quantitative real time polymerase chain reaction (qRT-PCR) in plasma samples of 8 homozygous TGR(mREN2)27 (Ren2) transgenic rats and 8 (control) Sprague-Dawley rats, 6 mice with angiotensin II-induced heart failure (AngII) and 6 control mice, and 8 mice with ischemic heart failure and 6 controls. Circulating miRNA levels were compared between the heart failure animals and healthy controls.Ren2 rats, AngII mice and mice with ischemic heart failure showed clear signs of heart failure, exemplified by increased left ventricular and lung weights, elevated end-diastolic left ventricular pressures, increased expression of cardiac stress markers and reduced left ventricular ejection fraction. All miRNAs were detectable in plasma from rats and mice. No significant differences were observed between the circulating miRNAs in heart failure animals when compared to the healthy controls (all P>0.05) and no robust associations with cardiac function could be found.The previous observation that miRNAs circulate in lower levels in human patients with heart failure could not be validated in well-established rat and mouse heart failure models. These results question the translation of data on human circulating miRNA levels to experimental models, and vice versa the validity of experimental miRNA data for human heart failure.
Project description:MicroRNAs (miRNAs) are small, noncoding ~22-nucleotide regulatory RNAs that are key regulators of gene expression programs. Their role in the context of the cardiovascular system has only recently begun to be explored; however, changes in the expression of miRNAs have been associated with cardiac development and with several pathophysiological states including myocardial hypertrophy and heart failure. We demonstrate that miRNA expression patterns are distinct in two types of heart failure: idiopathic dilated cardiomyopathy and ischemic cardiomyopathy. To pursue the observation that changes in expression levels of individual miRNAs are functionally relevant, microRNA mimics and inhibitors to miR-92, miR-100 and miR-133b were expressed in primary cultures of neonatal rat cardiac myocytes. These studies demonstrated that over-expression of miR-100 is involved in the beta-adrenergic receptor-mediated repression of "adult" cardiac genes (i.e., alpha-myosin heavy chain, SERCA2a), and that over-expression of miR-133b prevents changes in gene expression patterns mediated by beta-adrenergic receptor stimulation. In conclusion, some miRNA expression patterns appear to be unique to the etiology of cardiomyopathy and changes in the expression level of miRs 100 and 133b contribute to regulation of the fetal gene program. It is likely that this miR-directed reprogramming of key remodeling genes is involved in the establishment and progression of common human cardiomyopathies.