A MicroRNA Perspective on Cardiovascular Development and Diseases: An Update

Meta-analysis of Circulatory mitomiRs in stress Response: Unveiling the significance of miR-34a and miR-146a

BACKGROUND

MicroRNAs (miRNAs) are short, noncoding RNAs with essential roles in cellular pathways and are often associated with various diseases and stress conditions. Recently, they have been discovered in mitochondria, termed "mitomiRs," with unique functions. Mitochondria, crucial organelles for energy production and stress responses, Dysregulated mitomiRs functions and expression has been evident in stress conditions such as cardiovascular and neurodegenerative. In this meta-analysis we have systematically identified miR-34a & miR-146a as possible potential biomarkers for affliction.

METHODS

A meta-analysis was conducted to assess the potential role of miR-34a and miR-146a, two specific mitomiRs, as biomarkers in stress-related conditions. The study followed PRISMA guidelines, involving comprehensive database searches in May and September 2023. Twelve studies meeting predefined inclusion criteria were selected, and data analysis included the evaluation of miR-34a and miR-146a expression levels in various stress conditions compared to control groups. We also performed Gene ontology (GO) and Pathway enrichment analysis to observe how mitomiRs affects our body.

RESULTS

The meta-analysis revealed a significant increase in overall mitomiRs (miR-34a and miR-146a) expression levels in experimental groups experiencing different stress conditions compared to control groups (Z = 3.54, p < 0.05 using RevMan software). miR-34a demonstrated more pronounced upregulation and exhibited potential as a specific biomarker in certain stress-related conditions (Z = 2.22, p < 0.05). However, miR-146a did not show a significant difference, requiring further investigation in various stress-related contexts. The Analysis indicated a high degree of heterogeneity among the studies.

CONCLUSION

This meta-analysis emphasises the importance of mitomiRs, especially miR-34a, as potential biomarkers in the intricate interplay between stress, mitochondrial function, and disease. The study opens new avenues for exploring miRNAs' diagnostic and therapeutic applications in stress-related diseases, highlighting their pivotal role at the crossroads of molecular biology, psychology, and medicine.

MicroRNA-15b promotes cardiac ischemia injury by the inhibition of Mitofusin 2/PERK pathway

MicroRNA and mitofusin-2 (Mfn2) play an important role in the myocardial apoptosis induced by acute myocardial infarction (AMI). However, the target relationship and underlying mechanism associated with interorganelle interaction between endoplasmic reticulum (ER) and mitochondria under ischemic condition is not completely clear. MI-induced injury, Mfn2 expression, Mfn2-mediated mitochondrial function and ER stress, and target regulation by miRNA-15b (miR-15b) were evaluated by animal MI and cellular hypoxic models with advanced molecular techniques. The results confirmed that Mfn2 was down-regulated and miR-15b was up-regulated upon the target binding profile under ischemic/hypoxic condition. Our data showed that miR-15b caused cardiac apoptotic injury that was reversed by rAAV9-anti-miR-15b or AMO-15b. The damage effect of miR-15b on Mfn2 expression and mitochondrial function was observed and rescued by rAAV9-anti-miR-15b or AMO-15b. The targeted regulation of miR-15b on Mfn2 was verified by luciferase reporter and microRNA-masking. Importantly, miR-15b-mediated Mfn2 suppression activated PERK/CHOP pathway, by which leads to ER stress and mitochondrial dysfunction, and cardiac apoptosis eventually. In conclusion, our research, for the first time, revealed the missing molecular link in Mfn2 and apoptosis and elucidated that pro-apoptotic miR-15b plays crucial roles during the pathogenesis of AMI through down-regulation of Mfn2 and activation of PERK-mediated ER stress. These findings may provide an opportunity to develop new therapies for prophylaxis and treatment of ischemic heart disease.

Monocytic microRNAs-Novel targets in atherosclerosis therapy

Atherosclerosis is a chronic proinflammatory disease of the vascular wall resulting in narrowing of arteries due to plaque formation, thereby causing reduced blood supply that is the leading cause for diverse end-organ damage with high mortality rates. Monocytes/macrophages, activated by elevated circulating lipoproteins, are significantly involved in the formation and development of atherosclerotic plaques. The imbalance between proinflammatory and anti-inflammatory macrophages, arising from dysregulated macrophage polarization, appears to be a driving force in this process. Proatherosclerotic processes acting on monocytes/macrophages include accumulation of cholesterol in macrophages leading to foam cell formation, as well as dysfunctional efferocytosis, all of which contribute to the formation of unstable plaques. In recent years, microRNAs (miRs) were identified as factors that could modulate monocyte/macrophage function and may therefore interfere with the atherosclerotic process. In this review, we present effects of monocyte/macrophage-derived miRs on atherosclerotic processes in order to reveal new treatment options using miRmimics or antagomiRs.

MicroRNAs as novel biomarkers for the diagnosis and treatment of pediatric diseases

MicroRNAs (miRNAs) are highly conserved noncoding RNAs that regulate gene expression by silencing or degrading messenger RNAs. Many of the approximately 2,500 miRNAs discovered in humans are known to regulate vital biological processes, including cell differentiation, proliferation, apoptosis, and embryonic tissue development. Aberrant miRNA expression may have pathological and malignant consequences. Therefore, miRNAs have emerged as novel diagnostic markers and potential therapeutic targets for various diseases. Children undergo various stages of growth, development, and maturation between birth and adulthood. It is important to study the role of miRNA expression in normal growth and disease development during these developmental stages. In this mini-review, we discuss the role of miRNAs as diagnostic and prognostic biomarkers in various pediatric diseases.

The emerging role of miRNAs in myocardial infarction: From molecular signatures to therapeutic targets

Globally, myocardial infarction (MI) and other cardiovascular illnesses have long been considered the top killers. Heart failure and mortality are the results of myocardial apoptosis, cardiomyocyte fibrosis, and cardiomyocyte hypertrophy, all of which are caused by MI. MicroRNAs (miRNAs) play a crucial regulatory function in the progression and advancement of heart disease following an MI. By consolidating the existing data on miRNAs, our aim is to gain a more comprehensive understanding of their role in the pathological progression of myocardial injury after MI and to identify potential crucial target pathways. Also included are the primary treatment modalities and their most recent developments. miRNAs have the ability to regulate both normal and pathological activity, including the key signaling pathways. As a result, they may exert medicinal benefits. This review presents a comprehensive analysis of the role of miRNAs in MI with a specific emphasis on their impact on the regeneration of cardiomyocytes and other forms of cell death, such as apoptosis, necrosis, and autophagy. Furthermore, the targets of pro- and anti-MI miRNAs are comparatively elucidated.

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.

MicroRNA-499-5p inhibits transforming growth factor-β1-induced Smad2 signaling pathway and suppresses fibroblast proliferation and collagen synthesis in rat by targeting TGFβ-R1

BACKGROUND

Artial fibrosis has been recognized as a typical pathological change in atrial fibrillation. Although present evidence suggests that microRNA-499-5p (miR-499-5p) plays an important role in the development of atrial fibrosis, the specific mechanism is not fully understood. Therefore, this study attempted to assess the influence of miR-499-5p on atrial fibroblasts and explore the potential molecular mechanism.

METHODS

Atrial fibroblasts from sprague dawley rat were respectively transfected with miR-499-5p mimic, miR-499-5p negative control and miR-499-5p inhibitor, atrial fibroblasts without any treatment were also established. Cell counting kit-8 assay and transwell assay were used to detect the proliferation and migration of atrial fibroblasts in each group. Expressions of miR-499-5p, TGF-β1, smad2, α-SMA, collagen-I and TGFβ-R1 in mRNA and protein level were subsequently detected via quantitative real-time polymerase chain reaction and western blot. Furthermore, the prediction of the binding sites of miR-499-5p and TGFβ-R1 was performed via the bioinformatics online software TargetScan and verified by dual luciferase reporter.

RESULTS

By utilizing miR-499-5p-transfected atrial fibroblasts model, expression of miR-499-5p in the miR-499-5p mimic group was upregulated, while it was downregulated in the miR-499-5p inhibitors group. Upregulated miR-499-5p expression led to to a significant decrease in the proliferative and migratory ability of cultured atrial fibroblasts, while downregulated miR-499-5p expression led to a significant increase in the proliferative and migratory ability of cultured atrial fibroblasts. Additionally, upregulated miR-499-5p expression made a significant rise in TGF-β1-induced mRNA and protein expression of TGF-β1, TGFβ-R1, smad2, α-SMA and collagen-I in atrial fibroblasts. Furthermore, results from the dual luciferase reporter conformed that miR-499-5p may repress TGFβ-R1 by binding the 3'UTR of TGFβ-R1 directly.

CONCLUSIONS

miR-499-5p is able to inhibit the activation of transforming growth factor β-induced Smad2 signaling and eventually suppressed the proliferation, migration and invasion of atrial fibroblasts and collagen synthesis by targeting TGFβ-R1.

MicroRNA-22-3p alleviates atherosclerosis by mediating macrophage M2 polarization as well as inhibiting NLRP3 activation

OBJECTIVE

MicroRNA (miR)-22-3p is expressed in atherosclerosis (AS), but its function and regulatory mechanisms remain unclear. Therefore, the effects of miR-22-3p in AS were assessed in this study.

METHODS

MiR-22-3p expression was assessed in AS, and miR-22-3p target genes were predicted using sequencing transcriptomics. The effect of miR-22-3p agomir on atherosclerotic lesions in an AS mouse model were determined by Oil red O, Masson's, and sirius red staining, and by anti-smooth muscle actin and macrophage antigen-3 immunostaining. Gene expression in AS was evaluated by western blot and immunofluorescence.

RESULTS

MiR-22-3p was expressed in AS and control samples (32.5% and 33.9% levels, respectively, relative to total miRNA among six highly expressed miRNAs). In the mouse model of AS, miR-22-3p agomir significantly reduced lipid deposition, proliferation of aortic collagen fibres, and macrophage content. Additionally, inducible nitric oxide synthase, interleukin-6, and tumour necrosis factor-α levels were significantly reduced, and levels of arginase 1 and CD206 were significantly enhanced. MiR-22-3p was found to target janus kinase 1(JAK1), and significantly inhibited the activation of NLR family pyrin domain containing 3 (NLRP3) and JAK1 in mice.

CONCLUSIONS

MiR-22-3p appears to reduce the inflammatory response in AS, which might be achieved by inducing the M2 macrophage phenotype and suppressing NLRP3 activation via JAK1.

The potential role of miRNAs in the pathogenesis of cardiovascular diseases - A focus on signaling pathways interplay

For the past two decades since their discovery, scientists have linked microRNAs (miRNAs) to posttranscriptional regulation of gene expression in critical cardiac physiological and pathological processes. Multiple non-coding RNA species regulate cardiac muscle phenotypes to stabilize cardiac homeostasis. Different cardiac pathological conditions, including arrhythmia, myocardial infarction, and hypertrophy, are modulated by non-coding RNAs in response to stress or other pathological conditions. Besides, miRNAs are implicated in several modulatory signaling pathways of cardiovascular disorders including mitogen-activated protein kinase, nuclear factor kappa beta, protein kinase B (AKT), NOD-like receptor family pyrin domain-containing 3 (NLRP3), Jun N-terminal kinases (JNKs), Toll-like receptors (TLRs) and apoptotic protease-activating factor 1 (Apaf-1)/caspases. This review highlights the potential role of miRNAs as therapeutic targets and updates our understanding of their roles in the processes underlying pathogenic phenotypes of cardiac muscle.

Emerging Roles of Micrornas in Veterinary Cardiology

Simple Summary

MicroRNAs are promising novel biomarkers for the diagnosis and prognosis of cardiovascular diseases. These molecules are defined as a class of short-sequence non-coding RNAs that influence the expression of numerous genes. The growing understanding of cardiac biology contributed to recognising specific abnormal microRNA expression when diseases are present, which makes them potential biomarkers and therapeutical targets. Recent studies have analysed and discussed microRNA expression in cardiac diseases, such as myxomatous mitral valve disease, which are prevalent in our animal companions. This review summarises the most relevant microRNAs related to cardiovascular diseases in dogs and cats. In addition, it describes microRNA’s basic biology and function and discusses their potential as circulating biomarkers for diagnosis, prognosis and monitorisation of treatment, as well as their limitations. Although current studies describe microRNA expression in veterinary cardiology, further work is warranted before they are implemented in the clinical setting.

Abstract

Over the last years, the importance of microRNAs (miRNAs) has increasingly been recognised. Each miRNA is a short sequence of non-coding RNA that influences countless genes’ expression and, thereby, contributes to several physiological pathways and diseases. It has been demonstrated that miRNAs participate in the development of many cardiovascular diseases (CVDs). This review synopsises the most recent studies emphasising miRNA’s influence in several CVDs affecting dogs and cats. It provides a concise outline of miRNA’s biology and function, the diagnostic potential of circulating miRNAs as biomarkers, and their role in different CVDs. It also discusses known and future roles for miRNAs as potential clinical biomarkers and therapeutic targets. So, this review gives a comprehensive outline of the most relevant miRNAs related to CVDs in Veterinary Medicine.

Role of Different Types of miRNAs in Some Cardiovascular Diseases and Therapy-Based miRNA Strategies: A Mini Review

The role of microRNAs (miRNAs) in the pathogenesis of cardiovascular disease has been extensively studied. miRNAs have been highlighted as an important physiological regulator for activities like cardiac protection. miRNAs are present in the circulation, and they have been investigated as physiological markers, especially in the condition of heart failure. However, there is less compelling verification that miRNAs can outperform traditional biomarkers. However, clinical evidence is still required. In this review article, we explored the feasibility of miRNAs as diagnostic biomarkers for heart failure in a systematic study. Searching in the PubMed database to identify miRNA molecules that are differentially expressed between groups of patients with heart failure or heart disease and controls, throughout the investigation, we discovered no significant overlap in differentially expressed miRNAs. Only four miRNAs (“miR-126,” “miR-150-5p,” “hsa-miR-233,” and “miR-423-5p”) were differentially expressed. Results from our review show that there is not enough evidence to support the use of miRNAs as biomarkers in clinical settings.

Noncoding RNome as Enabling Biomarkers for Precision Health

Noncoding RNAs (ncRNAs), in the form of structural, catalytic or regulatory RNAs, have emerged to be critical effectors of many biological processes. With the advent of new technologies, we have begun to appreciate how intracellular and circulatory ncRNAs elegantly choreograph the regulation of gene expression and protein function(s) in the cell. Armed with this knowledge, the clinical utility of ncRNAs as biomarkers has been recently tested in a wide range of human diseases. In this review, we examine how critical factors govern the success of interrogating ncRNA biomarker expression in liquid biopsies and tissues to enhance our current clinical management of human diseases, particularly in the context of cancer. We also discuss strategies to overcome key challenges that preclude ncRNAs from becoming standard-of-care clinical biomarkers, including sample pre-analytics standardization, data cross-validation with closer attention to discordant findings, as well as correlation with clinical outcomes. Although harnessing multi-modal information from disease-associated noncoding RNome (ncRNome) in biofluids or in tissues using artificial intelligence or machine learning is at the nascent stage, it will undoubtedly fuel the community adoption of precision population health.

A panel of plasma microRNAs improves the assessment of surrogate markers of cardiovascular disease in rheumatoid arthritis patients

OBJECTIVE

Patients with rheumatoid arthritis (RA) present increased risk of cardiovascular (CV) disease compared with the general population. Moreover, CV risk factors that have causal relationship with atherosclerosis do not seem to fully explain the accelerated process that they exhibit. We evaluated the association of a 10 microRNAs panel with surrogate markers of subclinical arteriosclerosis (carotid intima media thickness (cIMT), carotid plaque presence (cPP), pulse wave velocity (PWV) and distensibility) in a cohort of RA patients.

METHODS

199 patients with RA were included. Surrogate markers of arteriosclerosis were measured with My Lab 60 X-Vision sonographer. MicroRNAs were extracted from plasma and quantified with qPCR. Multivariate models and classification methods were performed.

RESULTS

Multivariate models showed that microRNAs-24 (β  =  15.48), 125a (β  =  9.93), 132 (β  =  11.52), 146 (β  =  15.12), 191 (β  =  13.25) and 223 (β  =  13.30) were associated with cIMT globally. MicroRNA-24 (OR = 0.41), 146 (OR = 0.36) and Let7a (OR = 0.23) were associated with cPP in men. Including the microRNAs in a PLS-DA model properly classified men with and without cPP. MicroRNA-96 (β = -0.28) was associated with PWV in male patients. Finally, several miRNAs were also associated with cIMT, cPP and arterial stiffness in the high DAS28 group and in the earlier tertile groups of disease duration.

CONCLUSION

Plasmatic expression of microRNA-24, 96, 103, 125a, 132, 146, 191, 223 and Let7a were associated with surrogate markers of CV disease and could be predictors of CV risk in patients with RA.

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.

Deep sequencing unveils altered cardiac miRNome in congenital heart disease

Congenital heart disease (CHD) surges from fetal cardiac dysmorphogenesis and chiefly contributes to perinatal morbidity and cardiovascular disease mortality. A continual rise in prevalence and prerequisite postoperative disease management creates need for better understanding and new strategies to control the disease. The interaction between genetic and non-genetic factors roots the multifactorial status of this disease, which remains incompletely explored. The small non-coding microRNAs (miRs, miRNAs) regulate several biological processes via post-transcriptional regulation of gene expression. Abnormal expression of miRs in developing and adult heart is associated with anomalous cardiac cell differentiation, cardiac dysfunction, and cardiovascular diseases. Here, we attempt to discover the changes in cardiac miRNA transcriptome in CHD patients over those without CHD (non-CHD) and find its role in CHD through functional annotation. This study explores the miRNome in three most commonly occurring CHD subtypes, namely atrial septal defect (ASD), ventricular septal defect (VSD), and tetralogy of fallot (TOF). We found 295 dysregulated miRNAs through high-throughput sequencing of the cardiac tissues. The bioinformatically predicted targets of these differentially expressed miRs were functionally annotated to know they were entailed in cell signal regulatory pathways, profoundly responsible for cell proliferation, survival, angiogenesis, migration and cell cycle regulation. Selective miRs (hsa-miR-221-3p, hsa-miR-218-5p, hsa-miR-873-5p) whose expression was validated by qRT-PCR, have been reported for cardiogenesis, cardiomyocyte proliferation, cardioprotection and cardiac dysfunction. These results indicate that the altered miRNome to be responsible for the disease status in CHD patients. Our data expand the existing knowledge on the epigenetic changes in CHD. In future, characterization of these cardiac-specific miRs will add huge potential to understand cardiac development, function, and molecular pathogenesis of heart diseases with a prospect of epigenetic manipulation for cardiac repair.

MitomiRs: their roles in mitochondria and importance in cancer cell metabolism

Background

MicroRNAs (miRNAs) are short non-coding RNAs that play important roles in almost all biological pathways. They regulate post-transcriptional gene expression by binding to the 3’untranslated region (3’UTR) of messenger RNAs (mRNAs). MitomiRs are miRNAs of nuclear or mitochondrial origin that are localized in mitochondria and have a crucial role in regulation of mitochondrial function and metabolism. In eukaryotes, mitochondria are the major sites of oxidative metabolism of sugars, lipids, amino acids, and other bio-macromolecules. They are also the main sites of adenosine triphosphate (ATP) production.

Conclusions

In the review, we discuss the role of mitomiRs in mitochondria and introduce currently well studied mitomiRs, their target genes and functions. We also discuss their role in cancer initiation and progression through the regulation of mRNA expression in mitochondria. MitomiRs directly target key molecules such as transporters or enzymes in cell metabolism and regulate several oncogenic signaling pathways. They also play an important role in the Warburg effect, which is vital for cancer cells to maintain their proliferative potential. In addition, we discuss how they indirectly upregulate hexokinase 2 (HK2), an enzyme involved in glucose phosphorylation, and thus may affect energy metabolism in breast cancer cells. In tumor tissues such as breast cancer and head and neck tumors, the expression of one of the mitomiRs (miR-210) correlates with hypoxia gene signatures, suggesting a direct link between mitomiR expression and hypoxia in cancer. The miR-17/92 cluster has been shown to act as a key factor in metabolic reprogramming of tumors by regulating glycolytic and mitochondrial metabolism. This cluster is deregulated in B-cell lymphomas, B-cell chronic lymphocytic leukemia, acute myeloid leukemia, and T-cell lymphomas, and is particularly overexpressed in several other cancers. Based on the current knowledge, we can conclude that there is a large number of miRNAs present in mitochondria, termed mitomiR, and that they are important regulators of mitochondrial function. Therefore, mitomiRs are important players in the metabolism of cancer cells, which need to be further investigated in order to develop a potential new therapies for cancer.

Ovarian cancer: epigenetics, drug resistance, and progression

Ovarian cancer (OC) is one of the most common malignant tumors in women. OC is associated with the activation of oncogenes, the inactivation of tumor suppressor genes, and the activation of abnormal cell signaling pathways. Moreover, epigenetic processes have been found to play an important role in OC tumorigenesis. Epigenetic processes do not change DNA sequences but regulate gene expression through DNA methylation, histone modification, and non-coding RNA. This review comprehensively considers the importance of epigenetics in OC, with a focus on microRNA and long non-coding RNA. These types of RNA are promising molecular markers and therapeutic targets that may support precision medicine in OC. DNA methylation inhibitors and histone deacetylase inhibitors may be useful for such targeting, with a possible novel approach combining these two therapies. Currently, the clinical application of such epigenetic approaches is limited by multiple obstacles, including the heterogeneity of OC, insufficient sample sizes in reported studies, and non-optimized methods for detecting potential tumor markers. Nonetheless, the application of epigenetic approaches to OC patient diagnosis, treatment, and prognosis is a promising area for future clinical investigation.

Plasma expression of microRNA-425-5p and microRNA-451a as biomarkers of cardiovascular disease in rheumatoid arthritis patients

To validate in a cohort of 214 rheumatoid arthritis patients a panel of 10 plasmatic microRNAs, which we previously identified and that can facilitate earlier diagnosis of cardiovascular disease in rheumatoid arthritis patients. We identified 10 plasma miRs that were downregulated in male rheumatoid arthritis patients and in patients with acute myocardial infarction compared to controls suggesting that these microRNAs could be epigenetic biomarkers for cardiovascular disease in rheumatoid arthritis patients. Six of those microRNAs were validated in independent plasma samples from 214 rheumatoid arthritis patients and levels of expression were associated with surrogate markers of cardiovascular disease (carotid intima-media thickness, plaque formation, pulse wave velocity and distensibility) and with prior cardiovascular disease. Multivariate analyses adjusted for traditional confounders and treatments showed that decreased expression of microRNA-425-5p in men and decreased expression of microRNA-451 in women were significantly associated with increased (β = 0.072; p = 0.017) and decreased carotid intima-media thickness (β = −0.05; p = 0.013), respectively. MicroRNA-425-5p and microRNA-451 also increased the accuracy to discriminate patients with pathological carotid intima-media thickness by 1.8% (p = 0.036) in men and 3.5% (p = 0.027) in women, respectively. In addition, microRNA-425-5p increased the accuracy to discriminate male patients with prior cardiovascular disease by 3% (p = 0.008). Additionally, decreased expression of microRNA-451 was significantly associated with decreased pulse wave velocity (β = −0.72; p = 0.035) in overall rheumatoid arthritis population. Distensibility showed no significant association with expression levels of the microRNAs studied. We provide evidence of a possible role of microRNA-425-5p and microRNA-451 as useful epigenetic biomarkers to assess cardiovascular disease risk in patients with rheumatoid arthritis.

An Integrative Analysis of The Micro-RNAs Contributing in Stemness, Metastasis and B-Raf Pathways in Malignant Melanoma and Melanoma Stem Cell

Objective

Epithelial-mesenchymal transition (EMT) and the stemness potency in association with BRAF mutation are in dispensable to the progression of melanoma. Recently, microRNAs (miRNAs) have been introduced as the regulator of a multitude of oncogenic functions in most of tumors. Therefore identifying and interpreting the expression patterns of these miRNAs is essential. The present study sought to find common miRNAs regulating all three important pathways in melanoma development.

Materials and Methods

In this experimental study, 18 miRNAs that importantly contribute to EMT and have a role in regulating self-renewal and the BRAF pathway were selected based on current literature and cross-analysis with available databases. Subsequently, their expression patterns were evaluated in 20 melanoma patients, normal tissues, serum from patients and control subjects, and melanospheres. Pattern discovery and integrative regulatory network analysis were used to find the most important miRNAs in melanoma progression.

Results

Among 18 selected miRNAs, miR-205, -141, -203, -15b, and -9 were differentially expressed in tumor samples than normal tissues. Among them, miR-205, -15b, and -9 significantly expressed in serum samples and healthy donors. Attribute Weighting and decision trees (DT) analysis presented evidence that the combination of miR-205, -203, -9, and -15b can regulate self-renewal and EMT process, by affecting CDH1, CCND1, and VEGF expression.

Conclusion

We suggested here that miR-205, -15b, -203, -9 pattern as the key miRNAs linked to melanoma status, the pluripotency, proliferation, and motility of malignant cells. However, further investigations are required to find the mechanisms underlying the combinatory effects of the above mentioned miRNAs.

Behind the Adaptive and Resistance Mechanisms of Cancer Stem Cells to TRAIL

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), also known as Apo-2 ligand (Apo2L), is a member of the TNF cytokine superfamily. TRAIL has been widely studied as a novel strategy for tumor elimination, as cancer cells overexpress TRAIL death receptors, inducing apoptosis and inhibiting blood vessel formation. However, cancer stem cells (CSCs), which are the main culprits responsible for therapy resistance and cancer remission, can easily develop evasion mechanisms for TRAIL apoptosis. By further modifying their properties, they take advantage of this molecule to improve survival and angiogenesis. The molecular mechanisms that CSCs use for TRAIL resistance and angiogenesis development are not well elucidated. Recent research has shown that proteins and transcription factors from the cell cycle, survival, and invasion pathways are involved. This review summarizes the main mechanism of cell adaption by TRAIL to promote response angiogenic or pro-angiogenic intermediates that facilitate TRAIL resistance regulation and cancer progression by CSCs and novel strategies to induce apoptosis.

Behind the Adaptive and Resistance Mechanisms of Cancer Stem Cells to TRAIL

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), also known as Apo-2 ligand (Apo2L), is a member of the TNF cytokine superfamily. TRAIL has been widely studied as a novel strategy for tumor elimination, as cancer cells overexpress TRAIL death receptors, inducing apoptosis and inhibiting blood vessel formation. However, cancer stem cells (CSCs), which are the main culprits responsible for therapy resistance and cancer remission, can easily develop evasion mechanisms for TRAIL apoptosis. By further modifying their properties, they take advantage of this molecule to improve survival and angiogenesis. The molecular mechanisms that CSCs use for TRAIL resistance and angiogenesis development are not well elucidated. Recent research has shown that proteins and transcription factors from the cell cycle, survival, and invasion pathways are involved. This review summarizes the main mechanism of cell adaption by TRAIL to promote response angiogenic or pro-angiogenic intermediates that facilitate TRAIL resistance regulation and cancer progression by CSCs and novel strategies to induce apoptosis.

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.

Cyclic stretching boosts microRNA-499 to regulate Bcl-2 via microRNA-208a in atrial fibroblasts

MicroRNAs that modulate transcription can regulate other microRNAs and are also up-regulated under pathological stress. MicroRNA-499 (miR-499), microRNA-208a (miR-208a) and B-cell lymphoma 2 (Bcl-2) play roles in cardiovascular diseases, such as direct reprogramming of cardiac fibroblast into cardiomyocyte and cardiomyocyte apoptosis. Whether miR208a, miR499 and Bcl-2 were critical regulators in cardiac fibroblast apoptosis under mechanical stretching conditions in human cardiac fibroblasts-adult atrial (HCF-aa) was investigated. Using negative pressure, HCF-aa grown on a flexible membrane base were cyclically stretched to 20% of their maximum elongation. In adult rats, an aortocaval shunt was used to create an in vivo model of volume overload. MiR208a was up-regulated early by stretching and returned to normal levels with longer stretching cycles, whereas the expression of miR499 and Bcl-2 was up-regulated by longer stretching times. Pre-treatment with antagomir-499 reversed the miR-208a down-regulation, whereas Bcl-2 expression could be suppressed by miR-208a overexpression. In the HCF-aa under stretching for 1 h, miR-499 overexpression decreased pri-miR-208a luciferase activity; this inhibition of pri-miR-208a luciferase activity with stretching was reversed when the miR-499-5p binding site in pri-miR-208a was mutated. The addition of antagomir-208a reversed the Bcl-2-3'UTR suppression from stretching for 1 h. Flow cytometric analysis revealed that pre-treatment with miR-499 or antagomir-208a inhibited cellular apoptosis in stretched HCF-aa. In hearts with volume overload, miR-499 overexpression inhibited myocardial miR-208a expression, whereas Bcl-2 expression could be suppressed by the addition of miR-208a. In conclusion, miR-208a mediated the regulation of miR-499 on Bcl-2 expression in stretched HCF-aa and hearts with volume overload.

Therapeutic Approaches for Metastases from Colorectal Cancer and Pancreatic Ductal Carcinoma

Metastasis is the process of dissemination of a tumor, whereby cells from the primary site dislodge and find their way to other tissues where secondary tumors establish. Metastasis is the primary cause of death related to cancer. This process warrants changes in original tumoral cells and their microenvironment to establish a metastatic niche. Traditionally, cancer therapy has focused on metastasis prevention by systematic treatments or direct surgical re-sectioning. However, metastasis can still occur. More recently, new therapies direct their attention to targeting cancer stem cells. As they propose, these cells could be the orchestrators of the metastatic niche. In this review, we describe conventional and novel developments in cancer therapeutics for liver and lung metastasis. We further discuss the resistance mechanisms of targeted therapy, the advantages, and disadvantages of diverse treatment approaches, and future novel strategies to enhance cancer prognosis.

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.

Novel biomarkers to assess the risk for acute coronary syndrome: beyond troponins

Current diagnostic biomarkers for ACS are mainly represented by troponin I and troponin T. Dosing of these two molecules often leads to false positive results, since their plasma levels can increase in several different systemic settings. Therefore, identification of new markers able to detect patients with acute coronary syndromes is an emerging priority. On this view, many studies have been performed on different microRNAs, mitochondrial peptides, inflammatory cytokines and adhesion molecules with very promising results. Besides their introduction in screening programs, further studies are now needed in the acute setting, beyond or in association with troponin levels. This will help to better discriminate the real occurrence of an ACS in many patients accessing the emergency department for chest pain.

Prospective Advances in Non-coding RNAs Investigation

Non-coding RNAs (ncRNAs) play significant roles in numerous physiological cellular processes and molecular alterations during pathological conditions including heart diseases, cancer, immunological disorders and neurological diseases. This chapter is focusing on the basis of ncRNA relation with their functions and prospective advances in non-coding RNAs particularly miRNAs investigation in the cardiovascular disease management.The field of ncRNAs therapeutics is a very fascinating and challenging too. Scientists have opportunity to develop more advanced therapeutics as well as diagnostic approaches for cardiovascular conditions. Advanced studies are critically needed to deepen the understanding of the molecular biology, mechanism and modulation of ncRNAs and chemical formulations for managing CVDs.

Unveiling ncRNA regulatory axes in atherosclerosis progression

Completion of the human genome sequencing project highlighted the richness of the cellular RNA world, and opened the door to the discovery of a plethora of short and long non-coding RNAs (the dark transcriptome) with regulatory or structural potential, which shifted the balance of pathological gene alterations from coding to non-coding RNAs. Thus, disease risk assessment currently has to also evaluate the expression of new RNAs such as small micro RNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), competing endogenous RNAs (ceRNAs), retrogressed elements, 3'UTRs of mRNAs, etc. We are interested in the pathogenic mechanisms of atherosclerosis (ATH) progression in patients suffering Chronic Kidney Disease, and in this review, we will focus in the role of the dark transcriptome (non-coding RNAs) in ATH progression. We will focus in miRNAs and in the formation of regulatory axes or networks with their mRNA targets and with the lncRNAs that function as miRNA sponges or competitive inhibitors of miRNA activity. In this sense, we will pay special attention to retrogressed genomic elements, such as processed pseudogenes and Alu repeated elements, that have been recently seen to also function as miRNA sponges, as well as to the use or miRNA derivatives in gene silencing, anti-ATH therapies. Along the review, we will discuss technical developments associated to research in lncRNAs, from sequencing technologies to databases, repositories and algorithms to predict miRNA targets, as well as new approaches to miRNA function, such as integrative or enrichment analysis and their potential to unveil RNA regulatory networks.

MicroRNA-20b Promotes Cardiac Hypertrophy by the Inhibition of Mitofusin 2-Mediated Inter-organelle Ca2+ Cross-Talk

MicroRNA (miRNA) and mitofusin-2 (Mfn2) are important in the development of cardiac hypertrophy, but the target relationship and mechanism associated with Ca²⁺ handling between SR and mitochondria under hypertrophic condition is not established. Mfn2 expression, Mfn2-mediated interorganelle Ca²⁺ cross-talk, and target regulation by miRNA-20b (miR-20b) were evaluated using animal/cellular hypertrophic models with state-of-the-art techniques. The results demonstrated that Mfn2 was downregulated and miR-20b was upregulated upon the target binding profile under hypertrophic condition. Our data showed that miR-20b induced cardiac hypertrophy that was reversed by recombinant adeno-associated virus vector 9 (rAAV9)-anti-miR-20b or miR-20b antisense inhibitor (AMO-20b). The deleterious action of miR-20b on Mfn2 expression/function and mitochondrial ATP synthesis was observed and reversed by rAAV9-anti-miR-20b or AMO-20b. The targeted regulation of miR-20b on Mfn2 was confirmed by luciferase reporter and miRNA-masking. Importantly, the facts that mitochondrial calcium uniporter (MCU) activation by Spermine increased the cytosolic Ca²⁺ into mitochondria, manifested as enhanced histamine-mediated Ca²⁺ release from mitochondrial, suggesting that Ca²⁺ reuptake/buffering capability of mitochondria to cytosolic Ca²⁺ is injured by miR-20b-mediated Mfn2 signaling, by which leads cytosolic Ca²⁺ overload and cardiac hypertrophy through Ca²⁺ signaling pathway. In conclusion, pro-hypertonic miR-20b plays crucial roles in cardiac hypertrophy through downregulation of Mfn2 and cytosolic Ca²⁺ overload by weakening the buffering capability of mitochondria.

(-)-Epigallocatechin Gallate Promotes MicroRNA 145 Expression against Myocardial Hypoxic Injury through Dab2/Wnt3a/β-catenin

MicroRNA 145 (miR-145) is a critical modulator of cardiovascular diseases. The downregulation of myocardial miR-145 is followed by an increase in disabled-2 (Dab2) expression in cardiomyocytes. (-)-epigallocatechin gallate (EGCG) is a flavonoid that has been evaluated extensively due to its diverse pharmacological properties including anti-inflammatory effects. The aim of this study was to investigate the cardioprotective effects of EGCG under hypoxia-induced stress in vitro and in vivo. The hypoxic insult led to the suppression of miR-145 expression in cultured rat cardiomyocytes in a concentration-dependent manner. Western blotting and real-time PCR were performed. In rat myocardial infarction study, in situ hybridization, and immunofluorescent analyses were adopted. The western blot and real-time PCR data revealed that hypoxic stress with 2.5% O2 suppressed the expression of miR-145 and Wnt3a/[Formula: see text]-catenin in cultured rat cardiomyocytes but augmented Dab2. Treatment with EGCG attenuated Dab2 expression, but increased Wnt3a and [Formula: see text]-catenin in hypoxic cultured cardiomyocytes. Following in vivo myocardial infarction (MI) study, the data revealed the myocardial infarct area reduced by 48.5%, 44.6%, and 48.5% in EGCG (50[Formula: see text]mg/kg) or miR-145 dominant or Dab2 siRNA groups after myocardial infarction for 28 days, respectively. This study demonstrated that EGCG increased miR-145, Wnt3a, and [Formula: see text]-catenin expression but attenuated Dab2 expression. Moreover, EGCG ameliorated myocardial ischemia in vivo. The novel suppressive effect was mediated through the miR-145 and Dab2/Wnt3a/[Formula: see text]-catenin pathways.

LncRNA XIST knockdown ameliorates oxidative low-density lipoprotein-induced endothelial cells injury by targeting miR-204-5p/TLR4

Oxidative low-density lipoprotein (ox-LDL)-induced endothelial cell injury is a key contributor to atherosclerosis development. However, the role and mechanism of long noncoding RNA X-inactive specific transcript (XIST) in atherosclerosis remain largely unknown. The ox-LDL-induced human umbilical vein endothelial cells (HUVECs) injury was analyzed by cell viability, apoptosis, inflammatory cytokines secretion and oxidative stress. The expression levels of XIST, microRNA-204-5p (miR-204-5p) and toll-like receptor 4 (TLR4) were detected by quantitative real-time polymerase chain reaction and western blot, respectively. The target interaction between miR-204-5p and XIST or TLR4 was explored by bioinformatics analysis, luciferase assay and RNA immunoprecipitation. The expression of XIST was enhanced in ox-LDL-treated HUVECs. Knockdown of XIST attenuated ox-LDL-induced viability inhibition, apoptosis production, inflammatory response and oxidative stress in HUVECs. XIST was validated as a sponge of miR-204-5p and TLR4 acted as a target of miR-204-5p. Knockdown of miR-204-5p reversed silence of XISTmediated suppressive role in ox-LDL-induced injury. TLR4 alleviated miR-204-5p-mediated inhibitive effect on ox-LDL-induced injury. Moreover, XIST could regulate TLR4 expression by sponging miR-204-5p. In conclusion, silence of XIST displayed a protective role in ox-LDL-induced injury in HUVECs by regulating miR-204-5p/TLR4 axis, providing a novel mechanism for understanding the pathogenesis of atherosclerosis.

Downregulation of miR-542-3p promotes osteogenic transition of vascular smooth muscle cells in the aging rat by targeting BMP7

Background

Aging is believed to have a close association with cardiovascular diseases, resulting in various pathological alterations in blood vessels, including vascular cell phenotypic shifts. In aging vessels, the microRNA(miRNA)-mediated mechanism regulating the vascular smooth muscle cell (VSMC) phenotype remains unclarified. MiRNA microarray was used to compare the expressions of miRNAs in VSMCs from old rats (oVSMCs) and young rats (yVSMCs). Quantitative reverse transcription real-time PCR (qRT-PCR) and small RNA transfection were used to explore the miR-542-3p expression in oVSMCs and yVSMCs in vitro. Calcification induction of yVSMCs was conducted by the treatment of β-glycerophosphate (β-GP). Alizarin red staining was used to detect calcium deposition. Western blot and qRT-PCR were used to investigate the expression of the smooth muscle markers, smooth muscle 22α (SM22α) and calponin, and the osteogenic markers, osteopontin (OPN), and runt-related transcription factor 2 (Runx2). Lentivirus was used to overexpress miR-542-3p and bone morphogenetic protein 7 (BMP7) in yVMSCs. Luciferase reporter assay was conducted to identify the target of miR-542-3p.

Results

Compared with yVSMCs, 28 downregulated and 34 upregulated miRNAs were identified in oVSMCs. It was confirmed by qRT-PCR that oVSMC expressed four times lower miR-542-3p than yVSMCs. Overexpressing miR-542-3p in yVSMCs suppressed the osteogenic differentiation induced by β-GP. Moreover, miR-542-3p targets BMP7 and overexpressing BMP7 in miR-542-3p–expressing yVSMCs reverses miR-542-3p’s inhibition of osteogenic differentiation.

Conclusions

miR-542-3p regulates osteogenic differentiation of VSMCs through targeting BMP7, suggesting that the downregulation of miR-542-3p in oVSMCs plays a crucial role in osteogenic transition in the aging rat.

MicroRNA 3113-5p is a novel marker for early cardiac ischemia/reperfusion injury

BACKGROUND

Ischemia/reperfusion (I/R) injury of heart is one of the major causes of acute cardiac injury, which may result in worsening or even loss of heart function. With novel microRNAs being evolutionarily discovered, numbers of them remained functionally unknown. We aimed to discover novel microRNAs with therapeutic or diagnostic potential in the setting of early cardiac I/R injury.

METHODS

Cardiac electrical activity, biochemical detection and histopathology analysis were performed to reveal early changes of cardiac I/R injury. A microRNA array was performed to screen differential microRNAs in the mouse model of cardiac I/R injury. The differentially expressed microRNAs were validated in cardiac tissues and in serum samples.

RESULTS

The abnormality in electrocardiogram and increases in serum cTnI levels suggested the successful establishment of cardiac I/R injury in mice. A total of 1882 microRNAs were identified, of which 11 were significantly down-regulated and 41 were significantly up-regulated at 3 h post reperfusion. microRNA 223-3p and microRNA 3113-5p were among the mostly altered microRNAs and were validated to be up-regulated within the early hours of I/R injury in heart tissues. In the circulating system, cTnI, a sensitive marker of cardiac injury, or microRNA 223-3p only increased within the first 6 h post I/R injury. However, microRNA 3113-5p stably increased in the serum, keeping an increase of 2.5-fold throughout the 24 h. In the human serum samples, microRNA 3113-5p was detected to be significantly upregulated as soon as 3 h after I/R stimuli and kept significantly higher levels within the 48 h.

CONCLUSION

This is the first study that reported the functional roles of microRNA 3113-5p in cardiovascular system. Our data suggested that cardiac microRNA 3113-5p might be a useful target for therapeutic purposes and circulating microRNA 3113-5p might serve as a stable marker for early diagnosis of cardiac I/R injury.

Differential chamber-specific expression and regulation of long non-coding RNAs during cardiac development

Cardiovascular development is governed by a complex interplay between inducting signals such as Bmps and Fgfs leading to activation of cardiac specific transcription factors such as Nkx2.5, Mef2c and Srf that orchestrate the initial steps of cardiogenesis. Over the last decade we have witnessed the discovery of novel layers of gene regulation, i.e. post-transcriptional regulation exerted by non-coding RNAs. The function role of small non coding RNAs has been widely demonstrated, e.g. miR-1 knockout display several cardiovascular abnormalities during embryogenesis. More recently long non-coding RNAs have been also reported to modulate gene expression and function in the developing heart, as exemplified by the embryonic lethal phenotypes of Fendrr and Braveheart knock out mice, respectively. In this study, we investigated the differential expression profile during cardiogenesis of previously reported lncRNAs in heart development. Our data revealed that Braveheart, Fendrr, Carmen display a preferential adult expression while Miat, Alien, H19 preferentially display chamber-specific expression at embryonic stages. We also demonstrated that these lncRNAs are differentially regulated by Nkx2.5, Srf and Mef2c, Pitx2 > Wnt > miRNA signaling pathway and angiotensin II and thyroid hormone administration. Importantly isoform-specific expression and distinct nuclear vs cytoplasmic localization of Braveheart, Carmen and Fendrr during chamber morphogenesis is observed, suggesting distinct functional roles of these lncRNAs in atrial and ventricular chambers. Furthermore, we demonstrate by in situ hybridization a dynamic epicardial, myocardial and endocardial expression of H19 during cardiac development. Overall our data support novel roles of these lncRNAs in different temporal and tissue-restricted fashion during cardiogenesis.

MicroRNAs as Biomarkers and Therapeutic Targets in Heart Failure

Heart failure still represents a real challenge both in everyday practice and research, due to the complex issues related to its pathogenesis and management. Humoral biomarkers have emerged in the last decades as useful tools in the diagnosis, risk stratification and guiding the treatment of heart failure. These molecules are related to different pathological and adaptive processes, like myocardial injury, neurohormonal activation and cardiac remodeling, their most widespread representatives being the natriuretic peptides (e.g. NT-proBNP). The role of altered gene expression and transcription as the basis of myocardial structural and functional changes in heart failure is largely recognized. MicroRNAs (miRNAs) are non-coding RNAs which have a major role in post-transcriptional gene expression by interfering with messenger RNA molecules. Our short review summarizes the molecular biology of miRNAs and their possible role as biomarkers in the diagnosis and prognosis of heart failure. Furthermore, the therapeutical perspectives conferred by these molecules are also presented.

The role of microRNAs in congenital heart disease

Congenital heart diseases (CHDs) are the leading inherited cause of perinatal and infant mortality. CHD refers to structural anomalies of the heart and blood vessels that arise during cardiac development and represents a broad spectrum of malformations, including septal and valve defects, lesions affecting the outflow tract and ventricules. Advanced treatment strategies have greatly improved life expectancy and led to expanded population of adult patients with CHD. Thus, a better understanding of the pathogenesis and molecular mechanisms underlying CHDs is essential to improve the diagnosis and prognosis of patients. The etiology of CHD is largely unknown, genetic and environmental factors may contribute to the disease. In addition to the mutations affecting genomic DNA, epigenetic changes are being increasingly acknowledged as key factors in the development and progression of CHDs. The posttranscriptional regulation of gene expression by microRNAs (miRs) controls the highly complex multi-cell lineage process of cardiac tissue formation. In recent years, multiplex experimental models have provided evidence that changes in expression levels of miRs are associated with human cardiovascular disease, including CHD. The newly described correlations between miRs and heart development suggest the potential importance of miRs as diagnostic markers in human cardiovascular diseases. In the future, more intensive research is likely to be carried out to clarify their contribution to personalized management and treatment of CHD patients. In this paper, we discuss the current knowledge on the causative role of miRs in cardiac development and CHDs.

High serum CRP influences myocardial miRNA profiles in ischemia-reperfusion injury of rat heart

Objective

Prognosis of myocardial infarction tends to be worse when serum C-reactive protein (CRP) level is high. miRNAs are also known to be involved in different pathogeneses of heart diseases such as myocardial infarction. However, how CRP is involved in myocardial infarction has not been fully elucidated. We hypothesized that serum CRP changes the miRNA profile during ischemia-reperfusion injury (IRI) of the myocardium. To confirm this hypothesis, we performed global miRNA expression profiling of myocardium using IRI and CRP infusion rat model.

Methods

After ligation of the coronary artery of rat hearts, human serum CRP was intravenously injected, and reperfusion was performed (I/R+CRP group, n = 6). Control group consisted of the sham group (n = 3), IV CRP infusion group (CRP only, n = 3), and the I/R-only group (I/R only, n = 5). We evaluated 423 miRNA expression in non-ischemic areas and areas at risk (AAR) of each group using NanoString nCounter miRNA expression assay.

Results

MiR-124 was downregulated in non-ischemic myocardium in CRP-only group. In AAR, 7 miRNAs were commonly upregulated in both I/R-only and I/R+CRP groups. And additional 6 miRNAs were upregulated in the I/R+CRP group (miR-33, miR-409-3p, miR-384-3p, miR-3562, miR-101a, and miR-340-5p). Similarly, in the non-ischemic areas, 6 miRNAs were commonly upregulated in both I/R-only and I/R+CRP groups, and additional 5 miRNAs changed in the I/R+CRP group (upregulation of miR-3559-5p, miR-499, and miR-21 and downregulation of miR-500 and miR-532-3p).

Conclusion

We showed that when serum CRP level is high, IRI results in multiple miRNA profile changes not only in ischemic areas but also in non-ischemic myocardium. Our results may provide a strong basis for studying the role of CRP and miRNAs in ischemic heart disease.

Identification of Candidate Genes and Pathways in Dexmedetomidine-Induced Cardioprotection in the Rat Heart by Bioinformatics Analysis

Dexmedetomidine (DEX), a highly selective alpha2 adrenergic receptor agonist, directly protects hearts against ischemia/reperfusion (I/R) injury. However, the detailed mechanism has not been fully elucidated. We studied differentially expressed mRNAs and miRNAs after DEX administration in rat hearts by comprehensive analysis. Additionally, bioinformatics analysis was applied to explore candidate genes and pathways that might play important roles in DEX-induced cardioprotection. The results of microarray analysis showed that 165 mRNAs and 6 miRNAs were differentially expressed after DEX administration. Through bioinformatics analysis using differentially expressed mRNAs, gene ontology (GO) terms including MAP kinase tyrosine/serine/threonine phosphatase activity and pathways including the p53 pathway were significantly enriched in the down-regulated mRNAs. Dusp1 and Atm were associated with the GO term of MAP kinase tyrosine/serine/threonine phosphatase activity and the p53 pathway, respectively. On the other hand, no significant pathway was found in the target mRNAs of deregulated miRNAs. The results indicated some possible key genes and pathways that seem to be of significance in DEX-induced cardioprotection, although miRNAs seem to be unlikely to contribute to cardioprotection induced by DEX.

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.

MiR-1a-3p mitigates isoproterenol-induced heart failure by enhancing the expression of mitochondrial ND1 and COX1

MicroRNAs (miRNAs) have become potential targets for the treatment of heart failure (HF). It has been shown that miR-1 can reverse cardiac hypertrophy during the compensatory phase of HF development, but it is unknown whether miR-1 can still reverse cardiac dysfunction and improve cardiac remodeling after HF progresses to the decompensation stage. We established a mouse model of isoproterenol-induced HF and then injected miR-1a-3p agomir (agomir-1) into the tail vein. Echocardiography showed that the mice treated with agomir-1 had significantly increased ejection fraction and fractional shortening. These mice also showed a decrease in the N-terminal pro-B type natriuretic peptide (NT-proBNP) levels, but this remained higher than in controls. Cardiac hypertrophy, myocardial fibrosis, apoptosis, and glycogen deposition were reduced in mice treated with agomir-1. Furthermore, we found that supplementation of agomir-1 increased the expression of two mitochondrial DNA-encoded proteins, mitochondrially encoded NADH dehydrogenase 1 (ND1) and mitochondrially encoded cytochrome c oxidase I (COX1). In conclusion, our study found that miR-1a-3p alleviated the symptoms of ISO-induced HF in mice by enhancing mitochondrial ND1 and COX1. The results of this work may provide new therapeutic strategies for the treatment of HF patients.

MicroRNA-34 family: a potential tumor suppressor and therapeutic candidate in cancer

MicroRNA-34 (miR-34) has been reported to be dysregulated in various human cancers and regarded as a tumor suppressive microRNA because of its synergistic effect with the well-known tumor suppressor p53. Along with the application of MRX34, the first tumor-targeted microRNA drug which based on miR-34a mimics, on phase I clinical trial (NCT01829971), the significance of miR-34 is increasingly recognized. miR-34 plays a crucial role on repressing tumor progression by involving in epithelial-mesenchymal transition (EMT) via EMT- transcription factors, p53 and some important signal pathways. Not only that, numerous preclinical researches revealed the giant potential of miR-34a on cancer therapy through diversiform nano-scaled delivery systems. Here, we provide an overview about the function of miR-34 in various cancers and the mechanism of miR-34 in tumor-associated EMT. Furthermore, its potential role as a microRNA therapeutic candidate is also discussed. Notwithstanding some obstacles existed, the extensive application prospect of miR-34 on oncotherapy cannot be neglected.

Anesthetic-induced Myocardial Conditioning: Molecular Fundamentals and Scope

BACKGROUND

The pre- and post-conditioning effects of halogenated anesthetics make them most suitable for cardiac surgery. Several studies have demonstrated that the mechanism of drug-induced myocardial conditioning is enzyme-mediated via messenger RNA and miRNA regulation. The objective of this study was to investigate the role that miRNAs play in the cardioprotective effect of halogenated anesthetics. For such purpose, we reviewed the literature to determine the expression profile of miRNAs in ischemic conditioning and in the complications prevented by these phenomena.

METHODS

A review was conducted of more than 100 studies to identify miRNAs involved in anesthetic-induced myocardial conditioning. Our objective was to determine the miRNAs that play a relevant role in ischemic disease, heart failure and arrhythmogenesis, which expression is modulated by the perioperative administration of halogenated anesthetics. So far, no studies have been performed to assess the role of miRNAs in anesthetic-induced myocardial conditioning. The potential of miRNAs as biomarkers and miRNAs-based therapies involving the synthesis, inhibition or stimulation of miRNAs are a promising avenue for future research in the field of cardiology.

RESULTS

Each of the cardioprotective effects of myocardial conditioning is related to the expression of several (not a single) miRNAs. The cumulative evidence on the role of miRNAs in heart disease and myocardial conditioning opens new therapeutic and diagnostic opportunities.

CONCLUSION

Halogenated anesthetics regulate the expression of miRNAs involved in heart conditions. Further research is needed to determine the expression profile of miRNAs after the administration of halogenated drugs. The results of these studies would contribute to the development of new hypnotics for cardiac surgery patients.