Roles of miR-1-1 and miR-181c in ventricular septal defects

Epigenetic reprogramming of mtDNA and its etiology in mitochondrial diseases

Mitochondrial functionality and its regulation are tightly controlled through a balanced crosstalk between the nuclear and mitochondrial DNA interactions. Epigenetic signatures like methylation, hydroxymethylation and miRNAs have been reported in mitochondria. In addition, epigenetic signatures encoded by nuclear DNA are also imported to mitochondria and regulate the gene expression dynamics of the mitochondrial genome. Alteration in the interplay of these epigenetic modifications results in the pathogenesis of various disorders like neurodegenerative, cardiovascular, metabolic disorders, cancer, aging and senescence. These modifications result in higher ROS production, increased mitochondrial copy number and disruption in the replication process. In addition, various miRNAs are associated with regulating and expressing important mitochondrial gene families like COX, OXPHOS, ND and DNMT. Epigenetic changes are reversible and therefore therapeutic interventions like changing the target modifications can be utilized to repair or prevent mitochondrial insufficiency by reversing the changed gene expression. Identifying these mitochondrial-specific epigenetic signatures has the potential for early diagnosis and treatment responses for many diseases caused by mitochondrial dysfunction. In the present review, different mitoepigenetic modifications have been discussed in association with the development of various diseases by focusing on alteration in gene expression and dysregulation of specific signaling pathways. However, this area is still in its infancy and future research is warranted to draw better conclusions.

From genes to therapy: A comprehensive exploration of congenital heart disease through the lens of genetics and emerging technologies

Congenital heart disease (CHD) affects approximately 1 % of live births worldwide, making it the most common congenital anomaly in newborns. Recent advancements in genetics and genomics have significantly deepened our understanding of the genetics of CHDs. While the majority of CHD etiology remains unclear, evidence consistently indicates that genetics play a significant role in its development. CHD etiology holds promise for enhancing diagnosis and developing novel therapies to improve patient outcomes. In this review, we explore the contributions of both monogenic and polygenic factors of CHDs and highlight the transformative impact of emerging technologies on these fields. We also summarized the state-of-the-art techniques, including targeted next-generation sequencing (NGS), whole genome and whole exome sequencing (WGS, WES), single-cell RNA sequencing (scRNA-seq), human induced pluripotent stem cells (hiPSCs) and others, that have revolutionized our understanding of cardiovascular disease genetics both from diagnosis perspective and from disease mechanism perspective in children and young adults. These molecular diagnostic techniques have identified new genes and chromosomal regions involved in syndromic and non-syndromic CHD, enabling a more defined explanation of the underlying pathogenetic mechanisms. As our knowledge and technologies continue to evolve, they promise to enhance clinical outcomes and reduce the CHD burden worldwide.

Understanding the Genetic and Non-genetic Interconnections in the Aetiology of Isolated Congenital Heart Disease: An Updated Review: Part 1

PURPOSE OF REVIEW

Congenital heart disease (CHD) is the most frequently occurring birth defect. Majority of the earlier reviews focussed on the association of genetic factors with CHD. A few epidemiological studies provide convincing evidence for environmental factors in the causation of CHD. Although the multifactorial theory of gene-environment interaction is the prevailing explanation, explicit understanding of the biological mechanism(s) involved, remains obscure. Nonetheless, integration of all the information into one platform would enable us to better understand the collective risk implicated in CHD development.

RECENT FINDINGS

Great strides in novel genomic technologies namely, massive parallel sequencing, whole exome sequencing, multiomics studies supported by system-biology have greatly improved our understanding of the aetiology of CHD. Molecular genetic studies reveal that cardiac specific gene variants in transcription factors or signalling molecules, or structural proteins could cause CHD. Additionally, non-hereditary contributors such as exposure to teratogens, maternal nutrition, parental age and lifestyle factors also contribute to induce CHD. Moreover, DNA methylation and non-coding RNA are also correlated with CHD. Here, we inform that a complex combination of genetic, environmental and epigenetic factors interact to interfere with morphogenetic processes of cardiac development leading to CHD. It is important, not only to identify individual genetic and non-inherited risk factors but also to recognize which factors interact mutually, causing cardiac defects.

Role of miRNA in Cardiovascular Diseases in Children-Systematic Review

The number of children suffering from cardiovascular diseases (CVDs) is rising globally. Therefore, there is an urgent need to acquire a better understanding of the genetic factors and molecular mechanisms related to the pathogenesis of CVDs in order to develop new prevention and treatment strategies for the future. MicroRNAs (miRNAs) constitute a class of small non-coding RNA fragments that range from 17 to 25 nucleotides in length and play an essential role in regulating gene expression, controlling an abundance of biological aspects of cell life, such as proliferation, differentiation, and apoptosis, thus affecting immune response, stem cell growth, ageing and haematopoiesis. In recent years, the concept of miRNAs as diagnostic markers allowing discrimination between healthy individuals and those affected by CVDs entered the purview of academic debate. In this review, we aimed to systematise available information regarding miRNAs associated with arrhythmias, cardiomyopathies, myocarditis and congenital heart diseases in children. We focused on the targeted genes and metabolic pathways influenced by those particular miRNAs, and finally, tried to determine the future of miRNAs as novel biomarkers of CVD.

Crafting a Blueprint for MicroRNA in Cardiovascular Diseases (CVDs)

Cardiovascular diseases (CVDs) encompass a range of disorders, from congenital heart malformation, cardiac valve, peripheral artery, coronary artery, cardiac muscle diseases, and arrhythmias, ultimately leading to heart failure. Despite therapeutic advancements, CVDs remain the primary cause of global mortality, highlighting the need for a thorough knowledge of CVDs at the level of molecular structure. Gene and microRNA (miRNA) expression variations significantly influence cellular pathways, impacting an organism's physiology. MiRNAs, in particular, serve as regulators of gene expression, playing critical roles in essential cellular pathways and influencing the development of various diseases, including CVD. A wealth of evidence supports the involvement of miRNAs in CVD progression. These findings highlight the potential of miRNAs as valuable diagnostic biomarkers and open new avenues for their therapeutic application in CVDs. This study focuses on the latest advancements in identifying and characterizing microRNAs, exploring their manipulation and clinical application, and discussing future perspectives.

Spinal cord injury dysregulates fibro-adipogenic progenitors miRNAs signaling to promote neurogenic heterotopic ossifications

Neurogenic heterotopic ossifications are intramuscular bone formations developing following central nervous system injury. The pathophysiology is poorly understood and current treatments for this debilitating condition remain unsatisfying. Here we explored the role of miRNAs in a clinically relevant mouse model that combines muscle and spinal cord injury, and in patients' cells. We found an osteo-suppressive miRNAs response in injured muscle that was hindered when the spinal cord injury was associated. In isolated fibro-adipogenic progenitors from damaged muscle (cells at the origin of ossification), spinal cord injury induced a downregulation of osteo-suppressive miRNAs while osteogenic markers were overexpressed. The overexpression of selected miRNAs in patient's fibro-adipogenic progenitors inhibited mineralization and osteo-chondrogenic markers in vitro. Altogether, we highlighted an osteo-suppressive mechanism involving multiple miRNAs in response to muscle injury that prevents osteogenic commitment which is ablated by the neurologic lesion in heterotopic ossification pathogenesis. This provides new research hypotheses for preventive treatments.

Recent Advances of Using Exosomes as Diagnostic Markers and Targeting Carriers for Cardiovascular Disease

Cardiovascular diseases (CVDs) are the leading cause of human death worldwide. Exosomes act as endogenous biological vectors; they possess advantages of low immunogenicity and low safety risks, also providing tissue selectivity, including the inherent targeting the to heart. Therefore, exosomes not only have been applied as biomarkers for diagnosis and therapeutic outcome confirmation but also showed potential as drug carriers for cardiovascular targeting delivery. This review aims to summarize the progress and challenges of exosomes as novel biomarkers, especially many novel exosomal noncoding RNAs (ncRNAs), and also provides an overview of the improved targeting functions of exosomes by unique engineered approaches, the latest developed administration methods, and the therapeutic effects of exosomes used as the biocarriers of medications for cardiovascular disease treatment. Also, the possible therapeutic mechanisms and the potentials for transferring exosomes to the clinic for CVD treatment are discussed. The advances, in vivo and in vitro applications, modifications, mechanisms, and challenges summarized in this review will provide a general understanding of this promising strategy for CVD treatment.

Mitochondrial epigenetics in aging and cardiovascular diseases

Mitochondria are cellular organelles which generate adenosine triphosphate (ATP) molecules for the maintenance of cellular energy through the oxidative phosphorylation. They also regulate a variety of cellular processes including apoptosis and metabolism. Of interest, the inner part of mitochondria-the mitochondrial matrix-contains a circular molecule of DNA (mtDNA) characterised by its own transcriptional machinery. As with genomic DNA, mtDNA may also undergo nucleotide mutations that have been shown to be responsible for mitochondrial dysfunction. During physiological aging, the mitochondrial membrane potential declines and associates with enhanced mitophagy to avoid the accumulation of damaged organelles. Moreover, if the dysfunctional mitochondria are not properly cleared, this could lead to cellular dysfunction and subsequent development of several comorbidities such as cardiovascular diseases (CVDs), diabetes, respiratory and cardiovascular diseases as well as inflammatory disorders and psychiatric diseases. As reported for genomic DNA, mtDNA is also amenable to chemical modifications, namely DNA methylation. Changes in mtDNA methylation have shown to be associated with altered transcriptional programs and mitochondrial dysfunction during aging. In addition, other epigenetic signals have been observed in mitochondria, in particular the interaction between mtDNA methylation and non-coding RNAs. Mitoepigenetic modifications are also involved in the pathogenesis of CVDs where oxygen chain disruption, mitochondrial fission, and ROS formation alter cardiac energy metabolism leading to hypertrophy, hypertension, heart failure and ischemia/reperfusion injury. In the present review, we summarize current evidence on the growing importance of epigenetic changes as modulator of mitochondrial function in aging. A better understanding of the mitochondrial epigenetic landscape may pave the way for personalized therapies to prevent age-related diseases.

Multiple Copies of microRNA Binding Sites in Long 3'UTR Variants Regulate Axonal Translation

Rapid responses to changes within subcellular compartments of highly polarized cells, such as neuron axons, depend on local translation and post-transcriptional regulation. The mechanism by which microRNAs (miRNAs) regulate this process is not fully understood. Here, using live cell imaging and RNA sequencing analysis, we demonstrated how miRNAs can differentially control hundreds of transcripts at the subcellular level. We demonstrated that the seed match length of the miRNA target-sequence regulates both mRNA stability and protein translation rates. While longer seed matches have an increased inhibitory effect, transcriptome analysis did not reveal differences in seed match length between axonal and somata mRNAs of motor neurons. However, mRNA variants with longer 3'UTR are enriched in axons and contain multiple repeats of specific miRNA target sequences. Finally, we demonstrated that the long 3'UTR mRNA variant of the motor protein Kif5b is enriched explicitly in motor neuron axons and contains multiple sequence repeats for binding miR-129-5p. This subsequently results in the differential post-transcriptional regulation of kif5b and its synthesis in axons. Thus, we suggest that the number of miRNA binding sites at the 3'UTR of the mRNA, rather than the miRNA seed match length, regulates the axonal transcriptome.

Circulating microRNA: Myocardium-derived prenatal biomarker of ventricular septal defects

Background: Recently, circulating microRNAs (miRNAs) from maternal blood and amniotic fluid have been used as biomarkers for ventricular septal defect (VSD) diagnosis. However, whether circulating miRNAs are associated with fetal myocardium remains unknown.

Methods: Dimethadione (DMO) induced a VSD rat model. The miRNA expression profiles of the myocardium, amniotic fluid and maternal serum were analyzed. Differentially expressed microRNAs (DE-microRNAs) were verified by qRT–PCR. The target gene of miR-1-3p was confirmed by dual luciferase reporter assays. Expression of amniotic fluid-derived DE-microRNAs was verified in clinical samples.

Results: MiRNAs were differentially expressed in VSD fetal rats and might be involved in cardiomyocyte differentiation and apoptosis. MiR-1-3p, miR-1b and miR-293-5p were downregulated in the myocardium and upregulated in amniotic fluid/maternal serum. The expression of amniotic fluid-derived DE-microRNAs (miR-1-3p, miR-206 and miR-184) was verified in clinical samples. Dual luciferase reporter assays confirmed that miR-1-3p directly targeted SLC8A1/NCX1.

Conclusion: MiR-1-3p, miR-1b and miR-293-5p are downregulated in VSD myocardium and upregulated in circulation and may be released into circulation by cardiomyocytes. MiR-1-3p targets SLC8A1/NCX1 and participates in myocardial apoptosis. MiR-1-3p upregulation in circulation is a direct and powerful indicator of fetal VSD and is expected to serve as a prenatal VSD diagnostic marker.

Post-Transcriptional Regulation of Molecular Determinants during Cardiogenesis

Cardiovascular development is initiated soon after gastrulation as bilateral precardiac mesoderm is progressively symmetrically determined at both sides of the developing embryo. The precardiac mesoderm subsequently fused at the embryonic midline constituting an embryonic linear heart tube. As development progress, the embryonic heart displays the first sign of left-right asymmetric morphology by the invariably rightward looping of the initial heart tube and prospective embryonic ventricular and atrial chambers emerged. As cardiac development progresses, the atrial and ventricular chambers enlarged and distinct left and right compartments emerge as consequence of the formation of the interatrial and interventricular septa, respectively. The last steps of cardiac morphogenesis are represented by the completion of atrial and ventricular septation, resulting in the configuration of a double circuitry with distinct systemic and pulmonary chambers, each of them with distinct inlets and outlets connections. Over the last decade, our understanding of the contribution of multiple growth factor signaling cascades such as Tgf-beta, Bmp and Wnt signaling as well as of transcriptional regulators to cardiac morphogenesis have greatly enlarged. Recently, a novel layer of complexity has emerged with the discovery of non-coding RNAs, particularly microRNAs and lncRNAs. Herein, we provide a state-of-the-art review of the contribution of non-coding RNAs during cardiac development. microRNAs and lncRNAs have been reported to functional modulate all stages of cardiac morphogenesis, spanning from lateral plate mesoderm formation to outflow tract septation, by modulating major growth factor signaling pathways as well as those transcriptional regulators involved in cardiac development.

Restoring Ravaged Heart: Molecular Mechanisms and Clinical Application of miRNA in Heart Regeneration

Human heart development is a complex and tightly regulated process, conserving proliferation, and multipotency of embryonic cardiovascular progenitors. At terminal stage, progenitor cell type gets suppressed for terminal differentiation and maturation. In the human heart, most cardiomyocytes are terminally differentiated and so have limited proliferation capacity. MicroRNAs (miRNAs) are non-coding single-stranded RNA that regulate gene expression and mRNA silencing at the post-transcriptional level. These miRNAs play a crucial role in numerous biological events, including cardiac development, and cardiomyocyte proliferation. Several cardiac cells specific miRNAs have been discovered. Inhibition or overexpression of these miRNAs could induce cardiac regeneration, cardiac stem cell proliferation and cardiomyocyte proliferation. Clinical application of miRNAs extends to heart failure, wherein the cell cycle arrest of terminally differentiated cardiac cells inhibits the heart regeneration. The regenerative capacity of the myocardium can be enhanced by cardiomyocyte specific miRNAs controlling the cell cycle. In this review, we focus on cardiac-specific miRNAs involved in cardiac regeneration and cardiomyocyte proliferation, and their potential as a new clinical therapy for heart regeneration.

Role of miR-181c in Diet-induced obesity through regulation of lipid synthesis in liver

We recently identified a nuclear-encoded miRNA (miR-181c) in cardiomyocytes that can translocate into mitochondria to regulate mitochondrial gene mt-COX1 and influence obesity-induced cardiac dysfunction through the mitochondrial pathway. Because liver plays a pivotal role during obesity, we hypothesized that miR-181c might contribute to the pathophysiological complications associated with obesity. Therefore, we used miR-181c/d-/- mice to study the role of miR-181c in hepatocyte lipogenesis during diet-induced obesity. The mice were fed a high-fat (HF) diet for 26 weeks, during which indirect calorimetric measurements were made. Quantitative PCR (qPCR) was used to examine the expression of genes involved in lipid synthesis. We found that miR-181c/d-/- mice were not protected against all metabolic consequences of HF exposure. After 26 weeks, the miR-181c/d-/- mice had a significantly higher body fat percentage than did wild-type (WT) mice. Glucose tolerance tests showed hyperinsulinemia and hyperglycemia, indicative of insulin insensitivity in the miR-181c/d-/- mice. miR-181c/d-/- mice fed the HF diet had higher serum and liver triglyceride levels than did WT mice fed the same diet. qPCR data showed that several genes regulated by isocitrate dehydrogenase 1 (IDH1) were more upregulated in miR-181c/d-/- liver than in WT liver. Furthermore, miR-181c delivered in vivo via adeno-associated virus attenuated the lipogenesis by downregulating these same lipid synthesis genes in the liver. In hepatocytes, miR-181c regulates lipid biosynthesis by targeting IDH1. Taken together, the data indicate that overexpression of miR-181c can be beneficial for various lipid metabolism disorders.

Construction of the amniotic fluid-derived exosomal ceRNA network associated with ventricular septal defect

Ventricular septal defect (VSD) is the most frequent congenital cardiac malformations. Amniotic fluid (AF) contains a higher abundance of biological compounds that could reflect fetal health information. The aims of our study were to construct a competitive endogenous RNA (ceRNA) network based on AF-derived exosomal ncRNAs. We conducted whole transcriptome profiling in six pairs of AF-derived exosomes from VSD fetuses and matched healthy controls. A total of 1252 differentially expressed (DE) mRNAs, 256 DE-miRNAs and 1090 DE-lncRNAs were found to be significantly altered in the VSD group. We constructed a ceRNA regulatory network including 46 mRNAs, 11 miRNAs and 47 lncRNAs. The expression level of 6 hub RNAs were validated using qRT-PCR. In conclusion, AF-derived exosomal VSD-related ceRNAs provide a basis for a better understanding of the role of ncRNAs in the pathogenesis and mechanisms of VSD, which may lead to the discovery of potential diagnostic biomarkers for fetal VSD.

Usefulness of ischemia-modified albumin for assessment of the effects of small ventricular septal defects on the pulmonary vascular bed

BACKGROUND

Pulmonary vascular damage may be associated with oxidative stress in congenital heart diseases. We investigated whether small ventricular septal defects have an effect on the pulmonary bed.

METHODS

This prospective cohort study included 100 patients with small ventricular septal defects and 75 healthy controls. Ischemia-modified albumin, high-sensitivity C-reactive protein, and various cardiovascular parameters were assessed in both groups.

RESULTS

The mean ischemia-modified albumin level was significantly higher in patients with small ventricular septal defects (0.62 ± 0.17 absorbance units) than in the control group (0.51 ± 0.09 absorbance units; p < 0.001). The mean high-sensitivity C-reactive protein level was significantly higher in the ventricular septal defects group (3.72 ± 1.57) than in the control group (2.45 ± 0.89; p < 0.001). The ischemia-modified albumin levels in patients with left ventricular internal diameter end diastole and end sistole and main pulmonary artery z-scores ≥ 2 were significantly higher than patients whose z-scores were <2. The ischemia-modified albumin and high-sensitivity C-reactive protein levels were positively correlated in the small ventricular septal defects group (rho = 0.742, p < 0.001). Receiver operating characteristic analyses showed that at the optimal cut-off value of ischemia-modified albumin for the prediction of pulmonary involvement was 0.55 absorbance units with a sensitivity of 60%, specificity of 62% (area under the curve = 0.690, p < 0.001).

CONCLUSIONS

We demonstrated the presence of oxidative stress and higher ischemia-modified albumin levels in small ventricular septal defects, suggesting that ischemia-modified albumin might be a useful biomarker for evaluating the effects of small ventricular septal defects on the pulmonary bed.

miR-27b-3p Down-Regulation Prevents Hypoxia-Induced Cardiomyocyte Apoptosis Through Regulating Yes-Associated Protein 1 (YAP1) Expression

Background: Congenital heart disease (CHD) is one of the most common birth defects. MicroR-NAs (miRNAs) are a group of endogenous, non-coding small RNAs and mediate the target genes expression. An increasing evidence showed that in recent years, miRNAs have given rise to more and more attention in heart protection and development. In our research, the main purpose was to determine the effect of miR-27b-3p in CHD and analyze related mechanisms. Methods: We performed qRT-PCR analysis to examine miR-27b-3p expression in myocardial tissue from 30 patients with CHD and hypoxia-induced H9C2 cells. Then, we performed biological software TargetScan to predict the relationship of miR-27b-3p and YAP1, and dual luciferase reporter gene assay was used to verify the results. H9C2 cells were transfected with inhibitor control, miR-27b-3p inhibitor, miR-27b-3p inhibitor + control-siRNA or miR-27b-3p inhibitor + YAP1-siRNA for 6 hours and then induced by hypoxia for 72 hours. Subsequently, we performed MTT and FCM analysis to detect cell viability and apoptosis. Finally, we used western blot assay to measure the expression of apoptosis-related proteins. Results: Our study indicated that miR-27b-3p expression in myocardial samples of cyanotic CHD patients was significantly higher than that of the acyanotic CHD patients. miR-27b-3p expression was gradually up-regulated with the increase of hypoxia induction time in H9C2 cells. Besides, we confirmed that YAP1 was a target gene of miR-27b-3p. Moreover, our results showed that miR-27b-3p inhibitor improved cell viability, decreased apoptosis, and affected apoptosis-related proteins expression in hypoxia induced H9C2 cells. These changes were reversed by YAP1-siRNA. All data demonstrated that miR-27b-3p/YAP1 might be new potential bio-marker and therapeutic target for CHD treatment.

Genetic and epigenetic mechanisms in the development of congenital heart diseases

Congenital heart disease (CHD) is the most common of congenital cardiovascular malformations associated with birth defects, and it results in significant morbidity and mortality worldwide. The classification of CHD is still elusive owing to the complex pathogenesis of CHD. Advances in molecular medicine have revealed the genetic basis of some heart anomalies. Genes associated with CHD might be modulated by various epigenetic factors. Thus, the genetic and epigenetic factors are gradually accepted as important triggers in the pathogenesis of CHD. However, few literatures have comprehensively elaborated the genetic and epigenetic mechanisms of CHD. This review focuses on the etiology of CHD from genetics and epigenetics to discuss the role of these factors in the development of CHD. The interactions between genetic and epigenetic in the pathogenesis of CHD are also elaborated. Chromosome abnormalities and gene mutations in genetics, and DNA methylations, histone modifications and on-coding RNAs in epigenetics are summarized in detail. We hope the summative knowledge of these etiologies may be useful for improved diagnosis and further elucidation of CHD so that morbidity and mortality of children with CHD can be reduced in the near future.

The microbiome’s relationship with congenital heart disease: more than a gut feeling

Patients with congenital heart disease (CHD) are at risk for developing intestinal dysbiosis and intestinal epithelial barrier dysfunction due to abnormal gut perfusion or hypoxemia in the context of low cardiac output or cyanosis. Intestinal dysbiosis may contribute to systemic inflammation thereby worsening clinical outcomes in this patient population. Despite significant advances in the management and survival of patients with CHD, morbidity remains significant and questions have arisen as to the role of the microbiome in the inflammatory process. Intestinal dysbiosis and barrier dysfunction experienced in this patient population are increasingly implicated in critical illness. This review highlights possible CHD-microbiome interactions, illustrates underlying signaling mechanisms, and discusses future directions and therapeutic translation of the basic research.

Genome-wide analysis of primary microRNA expression using H3K36me3 ChIP-seq data

MicroRNAs are key players in gene regulatory networks controlling cell homeostasis. Their altered expression has been previously linked to disease outcomes and microRNAs thus serve as biomarkers for disease diagnostics. However, their synthesis and its transcriptional regulation have been challenging to investigate. In this study, we validated the use of H3K36me3 histone modification for the quantification of microRNA transcription levels using data from the ENCODE Consortium and then applied this approach to provide new insight into the cell-type-specific regulation in tissues, cell line models and cardiac disease. In cardiomyocytes derived from patients suffering from septal defects, carrying a G296S mutation in the transcription factor GATA4, we show that microRNA gene transcription is altered in cardiomyocytes carrying this mutation and coincides with novel super-enhancers formed within regulatory domains defined using chromatin interaction profiles. The most prominently elevated primary transcript encodes for let-7a and miR-100 that may target genes in the Hippo signaling pathway. Collectively, our work presents a methodology to quantify microRNA gene expression using histone marker data and paves the way for functional studies of cell-type-specific transcriptional regulation occurring in disease pathology.

Mending a broken heart: In vitro, in vivo and in silico models of congenital heart disease

Birth defects contribute to ∼0.3% of global infant mortality in the first month of life, and congenital heart disease (CHD) is the most common birth defect among newborns worldwide. Despite the significant impact on human health, most treatments available for this heterogenous group of disorders are palliative at best. For this reason, the complex process of cardiogenesis, governed by multiple interlinked and dose-dependent pathways, is well investigated. Tissue, animal and, more recently, computerized models of the developing heart have facilitated important discoveries that are helping us to understand the genetic, epigenetic and mechanobiological contributors to CHD aetiology. In this Review, we discuss the strengths and limitations of different models of normal and abnormal cardiogenesis, ranging from single-cell systems and 3D cardiac organoids, to small and large animals and organ-level computational models. These investigative tools have revealed a diversity of pathogenic mechanisms that contribute to CHD, including genetic pathways, epigenetic regulators and shear wall stresses, paving the way for new strategies for screening and non-surgical treatment of CHD. As we discuss in this Review, one of the most-valuable advances in recent years has been the creation of highly personalized platforms with which to study individual diseases in clinically relevant settings.

Potential Association of Circulating MicroRNA-181c and MicroRNA-484 Levels with Cardiorespiratory Fitness after Myocardial Infarction: A Pilot Study

Objectives:

In the field of exercise physiology, there has been great interest in exploring circulating microRNAs (miRs) as potential biomarkers. However, it remains to be determined whether circulating miRs reflect cardiorespiratory fitness. The aim of this study was to investigate the association between circulating levels of specific miRs and cardiorespiratory fitness evaluated by cardiopulmonary exercise testing (CPET) after acute myocardial infarction (MI).

Methods:

Twenty patients who had had an acute MI were included. All patients underwent CPET in the convalescent phase. Quantitative real-time polymerase chain reaction analyses for miR-181 members (a/b/c) and miR-484 were performed to determine the expression levels in the peripheral blood of the included patients and healthy control subjects (n=5).

Results:

Post-MI patients showed impaired exercise tolerance and ventilatory efficiency in CPET analysis. Compared with controls, circulating levels of miR-181a and 181c were gradually and significantly elevated through the 1st to 7th days after acute MI, whereas miR-181b and miR-484 were not. Circulating miR levels did not correlate with clinical or echocardiographic parameters. However, circulating levels of miR-181c and miR-484 on the 7th day showed significant positive correlations with the anaerobic threshold and peak oxygen consumption from CPET analysis. Moreover, miR-181c levels were inversely associated with the ventilatory inefficiency index. Patients with high exercise capacity after MI showed significantly higher expressions of circulating miR-181c and miR-484 than those with low exercise capacity.

Conclusions:

The results of this pilot study suggest that circulating levels of miR-181c and miR-484 after acute MI may be predictive biomarkers of post-MI cardiorespiratory fitness.

The Role of Epigenetics in Congenital Heart Disease

Congenital heart disease (CHD) is the most common birth defect among newborns worldwide and contributes to significant infant morbidity and mortality. Owing to major advances in medical and surgical management, as well as improved prenatal diagnosis, the outcomes for these children with CHD have improved tremendously so much so that there are now more adults living with CHD than children. Advances in genomic technologies have discovered the genetic causes of a significant fraction of CHD, while at the same time pointing to remarkable complexity in CHD genetics. For this reason, the complex process of cardiogenesis, which is governed by multiple interlinked and dose-dependent pathways, is a well investigated process. In addition to the sequence of the genome, the contribution of epigenetics to cardiogenesis is increasingly recognized. Significant progress has been made dissecting the epigenome of the heart and identified associations with cardiovascular diseases. The role of epigenetic regulation in cardiac development/cardiogenesis, using tissue and animal models, has been well reviewed. Here, we curate the current literature based on studies in humans, which have revealed associated and/or causative epigenetic factors implicated in CHD. We sought to summarize the current knowledge on the functional role of epigenetics in cardiogenesis as well as in distinct CHDs, with an aim to provide scientists and clinicians an overview of the abnormal cardiogenic pathways affected by epigenetic mechanisms, for a better understanding of their impact on the developing fetal heart, particularly for readers interested in CHD research.

Dysbiosis and Intestinal Barrier Dysfunction in Pediatric Congenital Heart Disease Is Exacerbated Following Cardiopulmonary Bypass

There are no data evaluating the microbiome in congenital heart disease following cardiopulmonary bypass. The authors evaluated patients with congenital heart disease undergoing cardiopulmonary bypass and noncardiac patients undergoing surgery without bypass. Patients with congenital heart disease had differences in baseline microbiome compared with control subjects, and this was exacerbated following surgery with bypass. Markers of barrier dysfunction were similar for both groups at baseline, and surgery with bypass induced significant intestinal barrier dysfunction compared with control subjects. This study offers novel evidence of alterations of the microbiome in congenital heart disease and exacerbation along with intestinal barrier dysfunction following cardiopulmonary bypass.

MicroRNAs: roles in cardiovascular development and disease

Cardiovascular diseases (CVDs) comprise a group of disorders ranging from peripheral artery, coronary artery, cardiac valve, cardiac muscle, and congenital heart diseases to arrhythmias and ultimately, heart failure. For all the advances in therapeutics, CVDs are still the leading cause of mortality the world over, hence the significance of a thorough understanding of CVDs at the molecular level. Disparities in the expressions of genes and microRNAs (miRNAs) play a crucial role in the determination of the fate of cellular pathways, which ultimately affect an organism's physiology. Indeed, miRNAs serve as the regulators of gene expressions in that they perform key functions both in several important cellular pathways and in the regulation of the onset of various diseases such as CVDs. Many miRNAs are expressed in embryonic, postnatal, and adult hearts; their aberrant expression or genetic deletion is associated with abnormal cardiac cell differentiation, disruption in heart development, and cardiac dysfunction. A substantial body of evidence implicates miRNAs in CVD development and suggests them as diagnostic biomarkers and intriguing therapeutic tools. The present review provides an overview of the history, biogenesis, and processing of miRNAs, as well as their function in the development, remodeling, and diseases of the heart.

microRNA-181 serves as a dual-role regulator in the development of human cancers

MicroRNAs (miRNAs) as the regulatory short noncoding RNAs are involved in a wide array of cellular and molecular processes. They negatively regulate gene expression and their dysfunction is correlated with cancer development through modulation of multiple signaling pathways. Therefore, these molecules could be considered as novel biomarkers and therapeutic targets for more effective management of human cancers. Recent studies have demonstrated that the miR-181 family is dysregulated in various tumor tissues and plays a pivotal role in carcinogenesis. They have been shown to act as oncomirs or tumor suppressors considering their mRNA targets and to be involved in cell proliferation, apoptosis, autophagy, angiogenesis and drug resistance. Additionally, these miRNAs have been demonstrated to exert their regulatory effects through modulating multiple signaling pathways including PI3K/AKT, MAPK, TGF-b, Wnt, NF-κB, Notch pathways. Given that, in this review, we briefly summarise the recent studies that have focused on the roles of miRNA-181 family as the multifunctional miRNAs in tumorigenesis and cancer development. These miRNAs may serve as diagnostic and prognostic biomarkers or therapeutic targets in human cancer gene therapy.

miR-181c Activates Mitochondrial Calcium Uptake by Regulating MICU1 in the Heart

Background

Translocation of miR‐181c into cardiac mitochondria downregulates the mitochondrial gene, mt‐COX1. miR‐181c/d^−/− hearts experience less oxidative stress during ischemia/reperfusion (I/R) and are protected against I/R injury. Additionally, miR‐181c overexpression can increase mitochondrial matrix Ca²⁺ ([Ca²⁺]_m), but the mechanism by which miR‐181c regulates [Ca²⁺]_m is unknown.

Methods and Results

By RNA sequencing and analysis, here we show that hearts from miR‐181c/d^−/− mice overexpress nuclear‐encoded Ca²⁺ regulatory and metabolic pathway genes, suggesting that alterations in miR‐181c and mt‐COX1 perturb mitochondria‐to‐nucleus retrograde signaling and [Ca²⁺]_m regulation. Quantitative polymerase chain reaction validation of transcription factors that are known to initiate retrograde signaling revealed significantly higher Sp1 (specificity protein) expression in the miR‐181c/d^−/− hearts. Furthermore, an association of Sp1 with the promoter region of MICU1 was confirmed by chromatin immunoprecipitation‐quantitative polymerase chain reaction and higher expression of MICU1 was found in the miR‐181c/d^−/− hearts. Conversely, downregulation of Sp1 by small interfering RNA decreased MICU1 expression in neonatal mouse ventricular myocytes. Changes in PDH activity provided evidence for a change in [Ca²⁺]_m via the miR‐181c/MICU1 axis. Moreover, this mechanism was implicated in the pathology of I/R injury. When MICU1 was knocked down in the miR‐181c/d^−/− heart by lentiviral expression of a short‐hairpin RNA against MICU1, cardioprotective effects against I/R injury were abrogated. Furthermore, using an in vitro I/R model in miR‐181c/d^−/− neonatal mouse ventricular myocytes, we confirmed the contribution of both Sp1 and MICU1 in ischemic injury.

Conclusions

miR‐181c regulates mt‐COX1, which in turn regulates MICU1 expression through the Sp1‐mediated mitochondria‐to‐nucleus retrograde pathway. Loss of miR‐181c can protect the heart from I/R injury by modulating [Ca²⁺]_m through the upregulation of MICU1.

Applications of miRNAs in cardiac development, disease progression and regeneration

Development of the complex human heart is tightly regulated at multiple levels, maintaining multipotency and proliferative state in the embryonic cardiovascular progenitors and thereafter suppressing progenitor characteristics to allow for terminal differentiation and maturation. Small regulatory microRNAs (miRNAs) are at the level of post-transcriptional gene suppressors, which enhance the degradation or decay of their target protein-coding mRNAs. These miRNAs are known to play roles in a large number of biological events, cardiovascular development being no exception. A number of critical cardiac-specific miRNAs have been identified, of which structural developmental defects have been linked to dysregulation of miRNAs in the proliferating cardiac stem cells. These miRNAs present in the stem cell niche are lost when the cardiac progenitors terminally differentiate, resulting in the postnatal mitotic arrest of the heart. Therapeutic applications of these miRNAs extend to the realm of heart failure, whereby the death of heart cells in the ageing heart cannot be replaced due to the arrest of cell division. By utilizing miRNA therapy to control cell cycling, the regenerative potential of matured myocardium can be restored. This review will address the various cardiac progenitor-related miRNAs that control the development and proliferative potential of the heart.

Long non-coding RNA MALAT1 functions as miR-1 sponge to regulate Connexin 43-mediated ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament (OPLL) is the major cause for several deteriorate bone and joint diseases. Its development is a highly organized dynamic process as modulated by various physiological and pathophysiological factors. Both long non-coding RNAs (lncRNAs) and small non-coding RNAs (miRNAs) have been postulated to involve into almost all the biological conditions. Here, we applied high through-put transcriptome screening to unveil lncRNAs highly regulated under OPLL condition. siRNA assay in combination with western blot and quantitative PCR deciphered the lncRNA and miRNA functions in OPLL and their underlying mechanism. Here we identified an lncRNA, named Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) engaged into the development of OPLL by indirectly targeting Connexin 43 (Cx43) gene. As previously reported, Cx43 is one of the main proteins contributing to OPLL partially through enhancing inflammatory signaling. On top of that, we provided another regulatory layer that MALAT1 served as the upstream effector governing the transcription of Cx43 gene. Perturbation of MALAT1 significantly inhibited Cx43 expression, inflammation, and osteogenesis. Mechanistically, in silico analysis and experimental validation both confirmed that microRNA-1 (miR-1) was the mediator connecting MALAT1-Cx43 axis: overexpression of miR-1 diminished Cx43 expression and OPLL process; meanwhile, MALAT1 acted as miR-1 sponge to inhibit its suppressive transcription effect on downstream ossification related genes. Knock-down of MALAT1 released sequestered miR-1, which repressed Cx43 expression and associated OPLL. Likewise, induced OPLL caused by overexpression of MALAT1 can be ameliorated by enhanced miR-1 function, knock-down of Cx43 or inhibition of inflammation. More importantly, further validation using patient ligament samples from non-OPLL and OPLL individuals identified MALAT1-miR-1-Cx43 regulatory axis. Collectively, we found a novel mechanism through lncRNA-miRNA interaction that provides more insights into understanding the development of OPLL.

miR-181c-5p Exacerbates Hypoxia/Reoxygenation-Induced Cardiomyocyte Apoptosis via Targeting PTPN4

Background

Activation of cell apoptosis is a major form of cell death during myocardial ischemia/reperfusion injury (I/RI). Therefore, examining ways to control cell apoptosis has important clinical significance for improving postischemic recovery. Clinical evidence demonstrated that miR-181c-5p was significantly upregulated in the early phase of myocardial infarction. However, whether or not miR-181c-5p mediates cardiac I/RI through cell apoptosis pathway is unknown. Thus, the present study is aimed at investigating the role and the possible mechanism of miR-181c-5p in apoptosis during I/R injury by using H9C2 cardiomyocytes.

Methods and Results

The rat origin H9C2 cardiomyocytes were subjected to hypoxia/reoxygenation (H/R, 6 hours hypoxia followed by 6 hours reoxygenation) to induce cell injury. The results showed that H/R significantly increased the expression of miR-181c-5p but not miR-181c-3p in H9C2 cells. In line with this, in an in vivo rat cardiac I/RI model, miR-181c-5p expression was also significantly increased. The overexpression of miR-181c-5p by its agomir transfection significantly aggravated H/R-induced cell injury (increased lactate dehydrogenase level and reduced cell viability) and exacerbated H/R-induced cell apoptosis (greater cleaved caspases 3 expression, Bax/Bcl-2 and more TUNEL-positive cells). In contrast, inhibition of miR-181c-5p in vitro had the opposite effect. By using computational prediction algorithms, protein tyrosine phosphatase nonreceptor type 4 (PTPN4) was predicted as a potential target gene of miR-181c-5p and was verified by the luciferase reporter assay. The overexpression of miR-181c-5p significantly attenuated the mRNA and protein expression of PTPN4 in H9C2 cardiomyocytes. Moreover, knockdown of PTPN4 significantly aggravated H/R-induced enhancement of LDH level, cleaved caspase 3 expression, and apoptotic cell death, which mimicked the proapoptotic effects of miR-181c-5p in H9C2 cardiomyocytes.

Conclusions

These findings suggested that miR-181c-5p exacerbates H/R-induced cardiomyocyte injury and apoptosis via targeting PTPN4 and that miR-181c-5p/PTPN4 signaling may yield novel strategies to combat myocardial I/R injury.

The Role of Non-Coding RNA in Congenital Heart Diseases

Cardiovascular development is a complex developmental process starting with the formation of an early straight heart tube, followed by a rightward looping and the configuration of atrial and ventricular chambers. The subsequent step allows the separation of these cardiac chambers leading to the formation of a four-chambered organ. Impairment in any of these developmental processes invariably leads to cardiac defects. Importantly, our understanding of the developmental defects causing cardiac congenital heart diseases has largely increased over the last decades. The advent of the molecular era allowed to bridge morphogenetic with genetic defects and therefore our current understanding of the transcriptional regulation of cardiac morphogenesis has enormously increased. Moreover, the impact of environmental agents to genetic cascades has been demonstrated as well as of novel genomic mechanisms modulating gene regulation such as post-transcriptional regulatory mechanisms. Among post-transcriptional regulatory mechanisms, non-coding RNAs, including therein microRNAs and lncRNAs, are emerging to play pivotal roles. In this review, we summarize current knowledge on the functional role of non-coding RNAs in distinct congenital heart diseases, with particular emphasis on microRNAs and long non-coding RNAs.

A MicroRNA Perspective on Cardiovascular Development and Diseases: An Update

In this review, we summarize the latest research pertaining to MicroRNAs (miRs) related to cardiovascular diseases. In today's molecular age, the key clinical aspects of diagnosing and treating these type of diseases are crucial, and miRs play an important role. Therefore, we have made a thorough analysis discussing the most important candidate protagonists of many pathways relating to such conditions as atherosclerosis, heart failure, myocardial infarction, and congenital heart disorders. We approach miRs initially from the fundamental molecular aspects and look at their role in developmental pathways, as well as regulatory mechanisms dysregulated under specific cardiovascular conditions. By doing so, we can better understand their functional roles. Next, we look at therapeutic aspects, including delivery and inhibition techniques. We conclude that a personal approach for treatment is paramount, and so understanding miRs is strategic for cardiovascular health.

At the heart of programming: the role of micro-RNAs

Epidemiological and experimental observations tend to prove that environment, lifestyle or nutritional challenges influence heart functions together with genetic factors. Furthermore, when occurring during sensitive windows of heart development, these environmental challenges can induce an 'altered programming' of heart development and shape the future heart disease risk. In the etiology of heart diseases driven by environmental challenges, epigenetics has been highlighted as an underlying mechanism, constituting a bridge between environment and heart health. In particular, micro-RNAs which are involved in each step of heart development and functions seem to play a crucial role in the unfavorable programming of heart diseases. This review describes the latest advances in micro-RNA research in heart diseases driven by early exposure to challenges and discusses the use of micro-RNAs as potential targets in the reversal of the pathophysiology.

miR-181c-3p and -5p promotes high-glucose-induced dysfunction in human umbilical vein endothelial cells by regulating leukemia inhibitory factor

Diabetes mellitus is a chronic metabolic disease with high blood glucose level and closely related to endothelial dysfunction, an important factor in the pathogenesis of vascular changes. Several miRNAs have been reported to be altered in a diabetic environment including miR-181c. In the article, we found that the expression of miR-181c-3p and miR-181c-5p was significantly downregulated under glucose treatment in a dose-dependent manner and in peripheral blood from diabetic patients compared with healthy participants. We explored the role of miR-181c-3p and miR-181c-5p in high glucose (HG)-induced dysfunction in human umbilical vein endothelial cells (HUVECs) by regulating leukemia inhibitory factor (LIF), their potential target with binding sites in 3-UTR region, that is also closely related to glucose metabolism. In addition, miR-181c-3p and miR-181c-5p significantly enhanced HG-induced oxidative stress injury by increasing malondialdehyde (MDA) and reactive oxygen species (ROS) production and promoted HG-induced HUVECs apoptosis, confirmed by TUNEL staining. LIF partially reduced those effects by decreasing oxidative stress and inhibiting cell apoptosis. Therefore, knocking down of LIF in HUVECs by LIF siRNA transfection, significantly increased HG-induced MDA and ROS production and induced more intense HUVECs apoptosis. Our results indicate that miR-181c-3p and miR-181c-5p promote HG-induced HUVECs injury through their target LIF.

Experience with genomic sequencing in pediatric patients with congenital cardiac defects in a large community hospital

BACKGROUND

Congenital cardiac defects, whether isolated or as part of a larger syndrome, are the most common type of human birth defect occurring on average in about 1% of live births depending on the malformation. As there is an expanding understanding of the underlying molecular mechanisms by which a cardiac defect may occur, there is a need to assess the current rates of diagnosis of cardiac defects by molecular sequencing in a clinical setting.

METHODS AND RESULTS

In this report, we evaluated 34 neonatal and pediatric patients born with a cardiac defect and their parents using exomized preexisting whole genome sequencing (WGS) data to model clinically available exon-based tests. Overall, we identified candidate variants in previously reported cardiac-related genes in 35% (12/34) of the probands. These include clearly pathogenic variants in two of 34 patients (6%) and variants of uncertain significance in relevant genes in 10 patients (26%), of these latter 10, 2 segregated with clinically apparent findings in the family trios.

CONCLUSIONS

These findings suggest that with current knowledge of the proteins underlying CHD, genomic sequencing can identify the underlying genetic etiology in certain patients; however, this technology currently does not have a high enough yield to be of routine clinical use in the screening of pediatric congenital cardiac defects.

A Rare Rs139365823 Polymorphism in Pre-miR-138 Is Associated with Risk of Congenital Heart Disease in a Chinese Population

miR-138 modulates cardiac morphogenesis in zebrafish. We explored whether a genetic polymorphism in miR-138 might contribute to the occurrence of sporadic congenital heart disease (CHD) and the potential mechanism. We performed a case-control study consisting of 857 CHD cases and 938 non-CHD controls by genotyping miR-138 in a Chinese population. Two SNPs, including rare rs139365823 located in the pre-miR-138 sequence and rs76987351 located in the pri-miR-138 sequence, were identified by sequencing miR-138. The results demonstrated that the genotypes and allele frequencies of the rs139365823 minor allele A were significantly associated with the increased risk of CHD cases overall or in the Tetralogy of Fallot (TOF) subtype, but not with the rs76987351 A/G allele. Real-time PCR data showed that the rs139365823 minor allele A significantly increased the expression of mature miR-138, whereas the rs76987351 minor allele A had the opposite effect. As TOF is caused by severe outflow tract (OFT) development and an alignment defect, we identified Dvl2, involved in OFT development, as a direct target of miR-138. Further, the rs139365823 minor allele A enhanced the miR-138-mediated inhibitory regulation of Dvl2. Taken together, our results demonstrated for the first time that the functional variant rs139365823 in pre-miR-138 altered the expression of mature miR-138 and its inhibitory effect on target genes and conferred the risk for CHD in the population studied here.

MicroRNA expression, target genes, and signaling pathways in infants with a ventricular septal defect

This study aimed to systematically investigate the relationship between miRNA expression and the occurrence of ventricular septal defect (VSD), and characterize the miRNA target genes and pathways that can lead to VSD. The miRNAs that were differentially expressed in blood samples from VSD and normal infants were screened and validated by implementing miRNA microarrays and qRT-PCR. The target genes regulated by differentially expressed miRNAs were predicted using three target gene databases. The functions and signaling pathways of the target genes were enriched using the GO database and KEGG database, respectively. The transcription and protein expression of specific target genes in critical pathways were compared in the VSD and normal control groups using qRT-PCR and western blotting, respectively. Compared with the normal control group, the VSD group had 22 differentially expressed miRNAs; 19 were downregulated and three were upregulated. The 10,677 predicted target genes participated in many biological functions related to cardiac development and morphogenesis. Four target genes (mGLUR, Gq, PLC, and PKC) were involved in the PKC pathway and four (ECM, FAK, PI3 K, and PDK1) were involved in the PI3 K-Akt pathway. The transcription and protein expression of these eight target genes were significantly upregulated in the VSD group. The 22 miRNAs that were dysregulated in the VSD group were mainly downregulated, which may result in the dysregulation of several key genes and biological functions related to cardiac development. These effects could also be exerted via the upregulation of eight specific target genes, the subsequent over-activation of the PKC and PI3 K-Akt pathways, and the eventual abnormal cardiac development and VSD.

Hypomethylation and decreased expression of BRG1 in the myocardium of patients with congenital heart disease

BACKGROUND

BRG1, an ATPase subunit of the SWItch/Sucrose Non-Fermentable complex, is tightly associated with cardiac development. However, little is known about the association between the pathogenesis of CHD and BRG1.

METHODS

The methylation of a BRG1 promoter and a novel CpG island in the second intron was analyzed in the myocardium of congenital heart disease (CHD) patients (n = 24) and normal controls (n = 11) using pyrosequencing and the MassARRAY platform. BRG1 expression was sketched in the normal fetal and postnatal heart using real-time PCR. BRG1 mRNA and protein expression was detected by means of real-time PCR and immunohistochemistry. The expression of GATA4 was analyzed with real-time PCR.

RESULTS

The CpG shore in the second intron of BRG1 was hypomethylated in the myocardium of patients (p < 0.05). BRG1 showed a high level of expression in the normal fetal heart in the second trimester (p < 0.01). Compared with that of the normal subjects, BRG1 expression was decreased by 70% in the myocardium of patients (n = 92; p < 0.05). Of note, the expression of GATA4 was significantly correlated with BRG1 expression (r = 0.7475; p = 0.0082) in the myocardium, and it was also decreased by 70% in these patients (n = 92; p < 0.05).

CONCLUSION

These results suggested that the early high expression of BRG1 in fetal hearts maintained normal cardiac development and that the abnormal hypomethylation and decreased expression of BRG1 in human hearts probably affect the expression of GATA4, which affects the pathogenesis of CHD. Birth Defects Research 109:1183-1195, 2017. © 2017 Wiley Periodicals, Inc.

miR-873 suppresses H9C2 cardiomyocyte proliferation by targeting GLI1

MicroRNAs (miRNAs) are a class of endogenous, non-coding small RNAs that regulate the expression of target genes. Previous studies have suggested that miRNAs are key regulators in cardiovascular systems. This study investigated the role of miR-873 in H9C2 cardiomyocytes by targeting glioma-associated oncogene 1 (GLI1). miR-873 was significantly up-regulated in serum samples from congenital heart disease (CHD) patients compared with those from normal individuals. Furthermore, miR-873 over-expression suppressed H9C2 proliferation and induced cell cycle arrest. Bioinformatic algorithms revealed a predicted target site for miR-873 in the 3'-untranslated region (3'UTR) of GLI1, which was verified using a dual-luciferase reporter assay. qPCR and western blot analysis also showed that miR-873 negatively regulated GLI1 mRNA and protein expression in H9C2 cells. Conversely, GLI1 over-expression partially reversed the growth-inhibitory effect of miR-873. To summarize, our data suggest that miR-873 is a novel miRNA that regulates H9C2 cell proliferation via targeting GLI1, and miR-873 may serve as a new potential biomarker diagnosis in CHD in the future.

MicroRNAs Association in the Cardiac Hypertrophy Secondary to Complex Congenital Heart Disease in Children

Complex congenital heart disease (CHD) affects cardiac blood flow, generating a pressure overload in the compromised ventricles and provoking hypertrophy that over time will induce myocardial dysfunction and cause a potential risk of imminent death. Therefore, the early diagnosis of complex CHD is paramount during the first year of life, with surgical treatment of patients favoring survival. In the present study, we analyzed cardiac tissue and plasma of children with cardiac hypertrophy (CH) secondary to CHD for the expression of 11 miRNAs specific to CH in adults. The results were compared with the miRNA expression patterns in tissue and blood of healthy children. In this way, we determined that miRNAs 1, 18b, 21, 23b, 133a, 195, and 208b constitute the expression profile of the cardiac tissue of children with CHD. Meanwhile, miRNAs 21, 23a, 23b, and 24 can be considered specific biomarkers for the diagnosis of CH in infants with CHD. These results suggest that CH secondary to CHD in children differs in its mechanism from that described for adult hypertrophy, offering a new perspective to study the development of this pathology and to determine the potential of hypertrophic miRNAs to be biomarkers for early CH.

MicroRNAs: pleiotropic players in congenital heart disease and regeneration

Congenital heart disease (CHD) is the leading cause of infant death, affecting approximately 4-14 live births per 1,000. Although surgical techniques and interventions have improved significantly, a large number of infants still face poor clinical outcomes. MicroRNAs (miRs) are known to coordinately regulate cardiac development and stimulate pathological processes in the heart, including fibrosis or hypertrophy and impair angiogenesis. Dysregulation of these regulators could therefore contribute (I) to the initial development of CHD and (II) at least partially to the observed clinical outcomes of many CHD patients by stimulating the aforementioned pathways. Thus, miRs may exhibit great potential as therapeutic targets in regenerative medicine. In this review we provide an overview of miR function and elucidate their role in selected CHDs, including hypoplastic left heart syndrome (HLHS), tetralogy of Fallot (TOF), ventricular septal defects (VSDs) and Holt-Oram syndrome (HOS). We then bridge this knowledge to the potential usefulness of miRs and/or their targets in therapeutic strategies for regenerative purposes in CHDs.

Circulating microRNAs as potential biomarkers for diagnosis of congenital heart defects

BACKGROUND

MicroRNAs are small non-coding RNAs of approximately 22 nucleotides in length, and play important regulatory roles in normal heart development and the pathogenesis of heart diseases. Recently, a few prospective studies have implicated the diagnostic role of microRNAs in congenital heart defects (CHD).

DATA RESOURCES

This review retrieved the research articles in PubMed focusing on the altered microRNAs in cardiac tissue or serum of patients with CHD versus healthy normal controls, as well as the studies exploring circulating microRNAs as potential biomarkers for (fetal) CHD.

RESULTS

Most of the studies of interest were conducted in recent years, implicating that the topic in this review is a newly emerging field and is drawing much attention. Moreover, a number of differentially expressed microRNAs between CHD specimens and normal controls have been reported.

CONCLUSION

Circulating microRNAs may serve as potential biomarkers for diagnosis of CHD in the future, with more efforts paving the road to the aim.

MicroRNAs in congenital heart disease

Congenital heart disease (CHD) is a broad term which encompasses a spectrum of pathology, the most common phenotypes include atrial septal defects (ASDs), ventricular septal defects (VSDs), patent ductus arteriosus (PAD) and tetralogy of Fallot (TOF). The impact of CHD is profound and it is estimated to be responsible for over 40% of prenatal deaths. MicroRNAs (miRs) are small, highly conserved, non-coding RNAs which have complex roles in a variety of pathophysiological states. miRs are post-transcriptional negative regulators of gene expression. Individual miRs are known to exert effects in multiple target genes, therefore the altered expression of a single miR could influence an entire gene network resulting in complex pathological states. Recent evidences suggest a role in the dysregulation of miRs in CHD. Mouse knock out models have contributed to our knowledge base revealing specific patterns of miR expression in cardiovascular physiology and pathological states. Specific miRs necessary for embryonic cardiac development have been revealed. Dysregulation of these miRs has been shown to cause structural abnormalities in the heart and vasculature, thus furthering our understanding of the processes which result in CHD. These advances have provided new insight into the signalling pathways responsible for CHD. Furthermore, this new appreciation for miRs in the development of CHD has uncovered their potential for new therapeutic targets where modulated miR activity may reduce the burden of disease. Here, we summarize current knowledge of the cause-effect relationships of miRs in CHD and consider their potential as a therapeutic targets and biomarkers in this clinical setting.

Regulatory RNAs controlling vascular (dys)function by affecting TGF-ß family signalling

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. Over the last few years, microRNAs (miRNAs) have emerged as master regulators of gene expression in cardiovascular biology and disease. miRNAs are small endogenous non-coding RNAs that usually bind to 3′ untranslated region (UTR) of their target mRNAs and inhibit mRNA stability or translation of their target genes. miRNAs play a dynamic role in the pathophysiology of many CVDs through their effects on target mRNAs in vascular cells. Recently, numerous miRNAs have been implicated in the regulation of the transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) signalling pathway which plays crucial roles in diverse biological processes, and is involved in pathogenesis of many diseases including CVD. This review gives an overview of current literature on the role of miRNAs targeting TGF-β/BMP signalling in vascular cells, including endothelial cells and smooth muscle cells. We also provide insight into how this miRNA-mediated regulation of TGF-β/BMP signalling might be used to harness CVD.

Protective effect of microRNA-30b on hypoxia/reoxygenation-induced apoptosis in H9C2 cardiomyocytes

We examined the protective role of microRNA-30b (miR-30b) in ischemia-reperfusion (I/R)-induced injury in rat H9C2 cardiomyocytes. H9C2 cells were subjected to hypoxia-reoxygenation (H/R) treatment to simulate ischemia-reperfusion (I/R) injury. H9C2 cells were divided into: vehicle control (VC) group; scrambled inhibitors (INC) group; scrambled mimics (MNC) group; H/R+VC group; H/R+INC group; H/R+mimics group. H/R induced apoptosis was detected by flow cytometry and the pathways involved in miR-30b-mediated protection were examined by analyzing the expression of miR-30b, Bcl-2, Bax, Caspase-3, KRAS, p-AKT and total AKT in H9C2 cells. Overexpression of miR-30b mimic (H/R+mimics group) significantly increased Bcl-2 and Bcl-2/Bax levels and decreased Bax and Caspase-3 levels, compared with the H/R+VC group (all P<0.05). Consistent with this, the apoptosis rate was significantly decreased in the H/R+mimics group (P<0.05) compared with the H/R+VC group. Western blot analysis revealed that overexpression of miR-30b mimic resulted in significantly increase in AKT activation and decreased KRAS, compared to the H/R+VC group (both P<0.05). In conclusion, the H/R induced apoptosis decreased miR-30b expression, but over-expression of miR-30b inhibited H/R induced apoptosis. The observed miR-30b-mediated protection against H/R induced apoptosis involved the upregulation of Ras-PI3K-Akt pathway.

Characterization of circulating microRNA expression in patients with a ventricular septal defect

OBJECTIVES

Ventricular septal defect (VSD), one of the most common types of congenital heart disease (CHD), results from a combination of environmental and genetic factors. Recent studies demonstrated that microRNAs (miRNAs) are involved in development of CHD. This study was to characterize the expression of miRNAs that might be involved in the development or reflect the consequences of VSD.

METHODS

MiRNA microarray analysis and reverse transcription-polymerase chain reaction (RT-PCR) were employed to determine the miRNA expression profile from 3 patients with VSD and 3 VSD-free controls. 3 target gene databases were employed to predict the target genes of differentially expressed miRNAs. miRNAs that were generally consensus across the three databases were selected and then independently validated using real time PCR in plasma samples from 20 VSD patients and 15 VSD-free controls. Target genes of validated 8 miRNAs were predicted using bioinformatic methods.

RESULTS

36 differentially expressed miRNAs were found in the patients with VSD and the VSD-free controls. Compared with VSD-free controls, expression of 15 miRNAs were up-regulated and 21 miRNAs were downregulated in the VSD group. 15 miRNAs were selected based on database analysis results and expression levels of 8 miRNAs were validated. The results of the real time PCR were consistent with those of the microarray analysis. Gene ontology analysis indicated that the top target genes were mainly related to cardiac right ventricle morphogenesis. NOTCH1, HAND1, ZFPM2, and GATA3 were predicted as targets of hsa-let-7e-5p, hsa-miR-222-3p and hsa-miR-433.

CONCLUSION

We report for the first time the circulating miRNA profile for patients with VSD and showed that 7 miRNAs were downregulated and 1 upregulated when matched to VSD-free controls. Analysis revealed target genes involved in cardiac development were probably regulated by these miRNAs.

miR-10a and miR-10b target the 3'-untranslated region of TBX5 to repress its expression

As a well-known transcription factor, TBX5 is involved in embryonic cardiac development. Although TBX5 functions in a dose-dependent manner, the posttranscriptional regulation of human TBX5 is poorly understood. Thus, this study aimed to identify microRNAs that modulate TBX5 expression. Luciferase assays were used to screen miRNAs predicted to modulate TBX5 expression. Using quantitative reverse transcriptase-polymerase chain reaction and Western blot analysis, the authors found that miR-10a and miR-10b significantly repressed TBX5 expression and decreased TBX5 protein levels by targeting the TBX5 3'-untranslated region. In addition, miR-10a and miR-10b expression levels were respectively 2.77 and 3.51 times higher in the heart tissues of congenital heart disease patients than in healthy control subjects, suggesting that they are potential diagnostic biomarkers. In conclusion, the study results indicate that miR-10a and miR-10b inhibit TBX5 expression at the level of translation. Higher levels of miR-10a and miR-10b expression are associated with a higher risk of congenital heart defects.