Expression of circulating microRNA-1 and microRNA-133 in pediatric patients with tachycardia

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.

Non-coding RNAs in human health and disease: potential function as biomarkers and therapeutic targets

Human diseases have been a critical threat from the beginning of human history. Knowing the origin, course of action and treatment of any disease state is essential. A microscopic approach to the molecular field is a more coherent and accurate way to explore the mechanism, progression, and therapy with the introduction and evolution of technology than a macroscopic approach. Non-coding RNAs (ncRNAs) play increasingly important roles in detecting, developing, and treating all abnormalities related to physiology, pathology, genetics, epigenetics, cancer, and developmental diseases. Noncoding RNAs are becoming increasingly crucial as powerful, multipurpose regulators of all biological processes. Parallel to this, a rising amount of scientific information has revealed links between abnormal noncoding RNA expression and human disorders. Numerous non-coding transcripts with unknown functions have been found in addition to advancements in RNA-sequencing methods. Non-coding linear RNAs come in a variety of forms, including circular RNAs with a continuous closed loop (circRNA), long non-coding RNAs (lncRNA), and microRNAs (miRNA). This comprises specific information on their biogenesis, mode of action, physiological function, and significance concerning disease (such as cancer or cardiovascular diseases and others). This study review focuses on non-coding RNA as specific biomarkers and novel therapeutic targets.

The Genetics and Epigenetics of Ventricular Arrhythmias in Patients Without Structural Heart Disease

Ventricular arrhythmia without structural heart disease is an arrhythmic disorder that occurs in structurally normal heart and no transient or reversible arrhythmia factors, such as electrolyte disorders and myocardial ischemia. Ventricular arrhythmias without structural heart disease can be induced by multiple factors, including genetics and environment, which involve different genetic and epigenetic regulation. Familial genetic analysis reveals that cardiac ion-channel disorder and dysfunctional calcium handling are two major causes of this type of heart disease. Genome-wide association studies have identified some genetic susceptibility loci associated with ventricular tachycardia and ventricular fibrillation, yet relatively few loci associated with no structural heart disease. The effects of epigenetics on the ventricular arrhythmias susceptibility genes, involving non-coding RNAs, DNA methylation and other regulatory mechanisms, are gradually being revealed. This article aims to review the knowledge of ventricular arrhythmia without structural heart disease in genetics, and summarizes the current state of epigenetic regulation.

Expression levels of serum circulating microRNAs in pediatric patients with ventricular and supraventricular arrhythmias

PURPOSE

Aberrant expression of various miRNA species has been implicated in numerous cardiac diseases, e.g., heart failure, hypertrophy, conduction disturbances, and arrhythmogenesis. The aim of this study was to determine whether miR-1, miR-133a, and miR-133b can serve as biomarkers in the diagnosis of ventricular (Va) and supraventricular (SVa) arrhythmias in pediatric patients.

MATERIALS AND METHODS

Molecular analysis included 30 patients with SVa or Va (13-17.5 years; 14 boys/16 girls) and 20 non-arrhythmic controls. Arrhythmia was confirmed by 24-h Holter ECG recording. miRNA was extracted from serum using the miRNeasy^R Serum/Plasma Kit. miScript SYBR Green PCR Kit (Qiagen) was used to quantify miRNA expression.

RESULTS

The levels of miR-1 and miR-133a expression were significantly higher in the SVa group than in the controls (p ​= ​0.0327 and p<0.0001, respectively). Additionally, both groups of patients with arrhythmia presented significantly lower expression levels of miR-133b than the controls (p<0.01 for both comparisons). The level of miR-133a expression in the SVa group was significantly higher than in the Va group (p ​= ​0.0124). ROC analysis demonstrated that the expressions of miR-1 and miR-133a could differentiate between the SVa patients and arrhythmia-free controls (AUC ​= ​0.7091, p ​= ​0.07 and AUC ​= ​0.8021, p ​= ​0.007, respectively). Furthermore, the expression of miR-133b was shown to distinguish patients with SVa and Va from the arrhythmia-free controls (AUC ​= ​0.7273, p ​= ​0.07 and AUC ​= ​0.8030, p ​= ​0.04, respectively).

CONCLUSIONS

miR-1, miR-133a, and miR-133b have the potential to become diagnostic biomarkers of arrhythmia in pediatric patients.

miR-133: A Suppressor of Cardiac Remodeling?

Cardiac remodeling, which is characterized by mechanical and electrical remodeling, is a significant pathophysiological process involved in almost all forms of heart diseases. MicroRNAs (miRNAs) are a group of non-coding RNAs of 20–25 nucleotides in length that primarily regulate gene expression by promoting mRNA degradation or post-transcriptional repression in a sequence-specific manner. Three miR-133 genes have been identified in the human genome, miR-133a-1, miR-133a-2, and miR-133b, which are located on chromosomes 18, 20, and 6, respectively. These miRNAs are mainly expressed in muscle tissues and appear to repress the expression of non-muscle genes. Based on accumulating evidence, miR-133 participates in the proliferation, differentiation, survival, hypertrophic growth, and electrical conduction of cardiac cells, which are essential for cardiac fibrosis, cardiac hypertrophy, and arrhythmia. Nevertheless, the roles of miR-133 in cardiac remodeling are ambiguous, and the mechanisms are also sophisticated, involving many target genes and signaling pathways, such as RhoA, MAPK, TGFβ/Smad, and PI3K/Akt. Therefore, in this review, we summarize the critical roles of miR-133 and its potential mechanisms in cardiac remodeling.

Circulating Noncoding RNAs as Biomarkers of Cardiovascular Disease and Injury

The discovery of thousands of noncoding RNAs (ncRNAs) has expanded our view on mammalian genomes and transcriptomes, as well as their organization and regulation. Accumulating evidence on aberrantly regulated ncRNAs, including short microRNAs, long ncRNAs and circular RNAs, across various heart diseases indicates that ncRNAs are critical contributors to cardiovascular pathophysiology. In addition, ncRNAs are released into the circulation where they are present in concentration levels that differ between healthy subjects and diseased patients. Although little is known about the origin and function of such circulating ncRNAs, these molecules are increasingly recognized as noninvasive and readily accessible biomarker for risk stratification, diagnosis and prognosis of cardiac injury, and multiple forms of cardiovascular disease. In this review, we summarize recent findings on biological characteristics of circulating ncRNAs and highlight their value as potential biomarker in selected pathologies of cardiovascular disease.

Acute responses of circulating microRNAs to low-volume sprint interval cycling

Low-volume high-intensity interval training is an efficient and practical method of inducing physiological responses in various tissues to develop physical fitness and may also change the expression of circulating microRNAs (miRNAs). The purpose of the present study was to examine whether miRNAs for muscle, heart, somatic tissue and metabolism were affected by 30-s intervals of intensive sprint cycling. We also examined the relationship of these miRNAs to conventional biochemical and performance indices. Eighteen healthy young males performed sprint interval cycling. Circulating miRNAs in plasma were detected using TaqMan-based quantitative PCR and normalized to Let-7d/g/i. In addition, we determined the levels of insulin-like growth factor-I, testosterone and cortisol, and anaerobic capacity. Compared to plasma levels before exercise muscle-specific miR-1 (0.12 ± 0.02 vs. 0.09 ± 0.02), miR-133a (0.46 ± 0.10 vs. 0.31 ± 0.06), and miR-133b (0.19 ± 0.02 vs. 0.10 ± 0.01) decreased (all P < 0.05), while miR-206 and miR-499 remained unchanged. The levels of metabolism related miR-122 (0.62 ± 0.07 vs. 0.34 ± 0.03) and somatic tissues related miR-16 (1.74 ± 0.27 vs. 0.94 ± 0.12) also decreased (both P < 0.05). The post-exercise IGF-1 and cortisol concentrations were significantly increased, while testosterone concentrations did not. Plasma levels of miR-133b correlated to peak power (r = 0.712, P = 0.001) and miR-122 correlated to peak power ratio (r = 0.665, P = 0.003). In conclusion sprint exercise provokes genetic changes for RNA related to specific muscle or metabolism related miRNAs suggesting that miR-133b and miR-122 may be potential useful biomarkers for actual physiological strain or anaerobic capacity. Together, our findings on the circulating miRNAs may provide new insight into the physiological responses that are being performed during exercise and delineate mechanisms by which exercise confers distinct phenotypes and improves performance.