MicroRNA expression in response to murine myocardial infarction: miR-21 regulates fibroblast metalloprotease-2 via phosphatase and tensin homologue

Good things come in small packages: The discovery of small RNAs in the smallest animal model

The 2024 Nobel Prize in Physiology or Medicine has been awarded to two pioneering researchers, Victor Ambros and Gary Ruvkun, marking the fourth time research using Caenorhabditis elegans (C. elegans) has received this prestigious recognition. With a rapid life cycle of just 3.5 days and four distinct larval stages, C. elegans serves as an ideal model for exploring complex genetic mechanisms, particularly heterochronic gene regulation. Ambros and Ruvkun's groundbreaking work on lin-4 and lin-14 genes in C. elegans revealed that lin-4 functions as a 22-nucleotide small RNA-now known as a microRNA (miRNA)-that binds complementarily to the 3' UTR of lin-14 mRNA, effectively inhibiting LIN-14 protein synthesis. This discovery was the first demonstration of miRNA in post-transcriptional gene regulation, a finding that has since reshaped our understanding of genetic regulation across species. Their research on small RNAs in C. elegans not only opened a new paradigm in molecular biology but also highlighted the power of this model organism in uncovering universal biological principles.

Physiological and cellular mechanisms of ischemic preconditioning microRNAs-mediated in underlying of ischemia/reperfusion injury in different organs

Ischemia-reperfusion (I/R) injury, as a pathological phenomenon, takes place when blood supply to an organ is disrupted and then aggravated during restoration of blood flow. Ischemic preconditioning (IPC) is a potent method for attenuating subsequent events of IR damage in numerous organs. IPC protocol is determined by a brief and sequential time periods of I/R before the main ischemia. MicroRNAs are endogenous non-coding RNAs that regulate post-transcriptionally target mRNA translation via degrading it and/or suppressing protein synthesis. This review introduces the physiological and cellular mechanisms of ischemic preconditioning microRNAs-mediated after I/R insult in different organs such as the liver, kidney, heart, brain, and intestine. Data of this review have been collected from the scientific articles published in databases such as Science Direct, Scopus, PubMed, Web of Science, and Scientific Information Database from 2000 to 2023. Based on these literature studies, IPC/IR intervention can affect cellular mechanisms including oxidative stress, apoptosis, angiogenesis, and inflammation through up-regulation or down-regulation of multiple microRNAs and their target genes.

Therapeutic potential of SMAD7 targeting miRNA in the pathogenesis of diabetic nephropathy

Diabetic nephropathy (DN) is a common complication of diabetes and a leading cause of end-stage renal disease, characterized by progressive kidney fibrosis and inflammation. The transforming growth factor-beta (TGF-β) signaling pathway plays a crucial role in the pathogenesis of diabetes nephropathy, and SMAD7 is a key negative regulator of this pathway. Recent studies have highlighted the involvement of miRNA in the progression of DN. Computational analysis identified 11 potential miRNAs such as miR-424, miR-195, miR-216a, miR-503, miR-15a-5p, miR-15b-5p, miR-665, miR-520h, miR16-5p, miR-21 and miR-32-5p which are predicted to target 3'UTR of SMAD7 mRNA. This review aims to explore the role of these miRNAs in the progression of DN. Notably, these miRNAs have shown therapeutic potential in mitigating fibrosis and inflammation by modulating SMAD7 expression in DN. Future directions can be to investigate the mechanistic pathways through which these miRNAs exert their effects, as well as optimizing delivery systems for effective clinical application. Targeting miRNAs that modulate SMAD7 expression represents a promising strategy for developing specific and effective therapies for diabetic nephropathy.

Exploring the role of pericardial miRNAs and exosomes in modulating cardiac fibrosis

The potential of the pericardial space as a therapeutic delivery tool for cardiac fibrosis and heart failure (HF) treatment has yet to be elucidated. Recently, miRNAs and exosomes have been discovered to be present in human pericardial fluid (PF). Novel studies have shown characteristic human PF miRNA compositions associated with cardiac diseases and higher miRNA expressions in PF compared to peripheral blood. Five key studies found differentially expressed miRNAs in HF, angina pectoris, aortic stenosis, ventricular tachycardia, and congenital heart diseases with either atrial fibrillation or sinus rhythm. As miRNA-based therapeutics for cardiac fibrosis and HF showed promising results in several in vivo studies for multiple miRNAs, we hypothesize a potential role of miRNA-based therapeutics delivered through the pericardial cavity. This is underlined by the favorable results of the first phase 1b clinical trial in this emerging field. Presenting the first human miRNA antisense drug trial, inhibition of miR-132 by intravenous administration of a novel antisense oligonucleotide, CDR132L, established efficacy in reducing miR-132 in plasma samples in a dose-dependent manner. We screened the literature, provided an overview of the miRNAs and exosomes present in PF, and drew a connection to those miRNAs previously elucidated in cardiac fibrosis and HF. Further, we speculate about clinical implications and potential delivery methods.

Current concepts in the epigenetic regulation of cardiac fibrosis

Cardiac fibrosis is a significant driver of congestive heart failure, a syndrome that continues to affect a growing patient population globally. Cardiac fibrosis results from a constellation of complex processes at the transcription, receptor, and signaling axes levels. Various mediators and signaling cascades, such as the transformation growth factor-beta pathway, have been implicated in the pathophysiology of cardiac tissue fibrosis. Our understanding of these markers and pathways has improved in recent years as more advanced technologies and assays have been developed, allowing for better delineation of the crosstalk between specific factors. There is mounting evidence suggesting that epigenetic modulation plays a pivotal role in the progression of cardiac fibrosis. Transcriptional regulation of key pro- and antifibrotic pathways can accentuate or blunt the rate and extent of fibrosis at the tissue level. Exosomes, micro-RNAs, and long noncoding RNAs all belong to factors that can impact the epigenetic signature in cardiac fibrosis. Herein, we comprehensively review the latest literature about exosomes, their contents, and cardiac fibrosis. In doing so, we highlight the specific transcriptional factors with pro- or antifibrotic properties. We also assimilate the data supporting these mediators' potential utility as diagnostic or prognostic biomarkers. Finally, we offer insight into where further work can be done to fill existing gaps to translate preclinical findings better and improve clinical outcomes.

Nucleic acid liquid biopsies in cardiovascular disease: Cell-free RNA liquid biopsies in cardiovascular disease

Cardiovascular diseases (CVD) and their complications continue to be the leading cause of mortality globally. With recent advancements in molecular analytics, individualized treatments are gradually applied to the diagnosis and treatment of CVD. In the field of diagnostics, liquid biopsy combined with modern analytical technologies is the most popular natural source to identify disease biomarkers, as has been successfully demonstrated in the cancer field. While it is not easy to obtain any diseased tissue for different types of CVD such as atherosclerosis, deep vein thrombosis or stroke, liquid biopsies provide a simple and non-invasive alternative to surgical tissue specimens to obtain dynamic molecular information reflecting disease states. The release of cell-free ribonucleic acids (cfRNA) from stressed/damaged/dying and/or necrotic cells is a common physiological phenomenon. CfRNAs are a heterogeneous population of various types of extracellular RNA found in body fluids (blood, urine, saliva, cerebrospinal fluid) or in association with vascular/atherosclerotic tissue, offering insights into disease pathology on a diagnostic front. In particular, cf-ribosomal RNA has been shown to act as a damaging molecule in several cardio-vascular disease conditions. Moreover, such pathophysiological functions of cfRNA in CVD have been successfully antagonized by the administration of RNases. In this review, we discuss the origin, structure, types, and potential utilization of cfRNA in the diagnosis of CVD. Together with the analysis of established CVD biomarkers, the profiling of cfRNA in body fluids may thereby provide a promising approach for early disease detection and monitoring.

Roles and Mechanisms of miRNAs in Abdominal Aortic Aneurysm: Signaling Pathways and Clinical Insights

PURPOSE OF REVIEW

Abdominal aortic aneurysm refers to a serious medical condition that can cause the irreversible expansion of the abdominal aorta, which can lead to ruptures that are associated with up to 80% mortality. Currently, surgical and interventional procedures are the only treatment options available for treating abdominal aortic aneurysm patients. In this review, we focus on the upstream and downstream molecules of the microRNA-related signaling pathways and discuss the roles, mechanisms, and targets of microRNAs in abdominal aortic aneurysm modulation to provide novel insights for precise and targeted drug therapy for the vast number of abdominal aortic aneurysm patients.

RECENT FINDINGS

Recent studies have highlighted that microRNAs, which are emerging as novel regulators of gene expression, are involved in the biological activities of regulating abdominal aortic aneurysms. Accumulating studies suggested that microRNAs modulate abdominal aortic aneurysm development through various signaling pathways that are yet to be comprehensively summarized. A total of six signaling pathways (NF-κB signaling pathway, PI3K/AKT signaling pathway, MAPK signaling pathway, TGF-β signaling pathway, Wnt signaling pathway, and P53/P21 signaling pathway), and a total of 19 miRNAs are intimately associated with the biological properties of abdominal aortic aneurysm through targeting various essential molecules. MicroRNAs modulate the formation, progression, and rupture of abdominal aortic aneurysm by regulating smooth muscle cell proliferation and phenotype change, vascular inflammation and endothelium function, and extracellular matrix remodeling. Because of the broad crosstalk among signaling pathways, a comprehensive analysis of miRNA-mediated signaling pathways is necessary to construct a well-rounded upstream and downstream regulatory network for future basic and clinical research of AAA therapy.

Circulating miRNA-21 as a diagnostic biomarker for acute coronary syndrome: a systematic review and meta-analysis of diagnostic test accuracy study

Background

Both early detection and treatment for acute coronary syndrome (ACS) have positively affected prognosis. A microRNA, miRNA-21 (miR-21), may have additional diagnostic potential for ACS among the others. This systematic review and meta-analysis aimed to evaluate the potential role of miR-21 in identifying ACS.

Methods

PubMed, EMBASE and CENTRAL databases were searched up to March 17, 2024, for case-control and cohort studies assessing the diagnostic value of circulating miR-21 in patients with ACS. The search was limited to studies published in either English or Chinese. The primary outcome was the discriminative ability to circulate miR-21 for ACS, represented by the area under the standard receiver operating characteristic curve (AUC) analysis. Meta-analyses combined the AUCs using a random-effects model. Heterogeneity among the studies was detected by the I2 and Q statistics. The quality of the studies included was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2. Publication bias analysis was assessed constructing by the Egger's test (PROSPERO: CRD42020209424).

Results

Eleven case-control studies containing a total of 2,413 subjects with 1,236 ACS cases and 1,177 controls were included. The mean age of participants in these studies ranges between 51.0 and 69.0 years. The meta-analysis showed an overall pooled AUC of 0.779 [95% confidence interval (CI): 0.715-0.843], with high heterogeneity noted between the studies (Q statistic =190.64, I2=94.23%, P<0.001). In subgroup analyses according to the subtypes of ACS, a pooled AUC of 0.767 (95% CI: 0.648-0.887) was derived from the studies focused on acute myocardial infarction cases only. The pooled AUC for unstable angina was 0.770 (95% CI: 0.718-0.822). In subgroup analyses according to the types of control groups, pooled AUC for ACS versus healthy controls was 0.779 (95% CI: 0.715-0.843), whereas the pooled AUC for ACS versus unhealthy controls was 0.740 (95% CI: 0.645-0.836). The quality assessment showed that the studies' overall quality was moderate. No evidence of publication bias was noted (P=0.49).

Conclusions

Circulating miR-21 shows abilities to differentiate between ACS and non-ACS, suggesting its potential as a novel diagnostic biomarker for ACS. However, the evidence is weakened by high heterogeneity observed among the studies. Further research is essential before it can be applied in clinical practice.

MiR-181a protects the heart against myocardial infarction by regulating mitochondrial fission via targeting programmed cell death protein 4

Worldwide, myocardial infarction (MI) is the leading cause of death and disability-adjusted life years lost. Recent researches explored new methods of detecting biomarkers that can predict the risk of developing myocardial infarction, which includes identifying genetic markers associated with increased risk. We induced myocardial infarction in mice by occluding the left anterior descending coronary artery and performed TTC staining to assess cell death. Next, we performed ChIP assays to measure the enrichment of histone modifications at the promoter regions of key genes involved in mitochondrial fission. We used qPCR and western blot to measure expression levels of relative apoptotic indicators. We report that miR-181a inhibits myocardial ischemia-induced apoptosis and preserves left ventricular function after MI. We show that programmed cell death protein 4 (PDCD4) is the target gene involved in miR-181a-mediated anti-ischemic injury, which enhanced BID recruitment to the mitochondria. In addition, we discovered that p53 inhibits the expression of miR-181a via transcriptional regulation. Here, we discovered for the first time a mitochondrial fission and apoptosis pathway which is controlled by miR-181a and involves PDCD4 and BID. This pathway may be controlled by p53 transcriptionally, and we presume that miR-181a may lead to the discovery of new therapeutic and preventive targets for ischemic heart diseases.

Current evidence regarding the cellular mechanisms associated with cancer progression due to cardiovascular diseases

Several large cohort studies in cardiovascular disease (CVD) patients have shown an increased incidence of cancer. Previous studies in a myocardial infarction (MI) mouse model reported increased colon, breast, and lung cancer growth. The potential mechanisms could be due to secreted cardiokines and micro-RNAs from pathological hearts and immune cell reprogramming. A study in a MI-induced heart failure (HF) mouse demonstrated an increase in cardiac expression of SerpinA3, resulting in an enhanced proliferation of colon cancer cells. In MI-induced HF mice with lung cancer, the attenuation of tumor sensitivity to ferroptosis via the secretion of miR-22-3p from cardiomyocytes was demonstrated. In MI mice with breast cancer, immune cell reprogramming toward the immunosuppressive state was shown. However, a study in mice with renal cancer reported no impact of MI on tumor growth. In addition to MI, cardiac hypertrophy was shown to promote the growth of breast and lung cancer. The cardiokine potentially involved, periostin, was increased in the cardiac tissue and serum of a cardiac hypertrophy model, and was reported to increase breast cancer cell proliferation. Since the concept that CVD could influence the initiation and progression of several types of cancer is quite new and challenging regarding future therapeutic and preventive strategies, further studies are needed to elucidate the potential underlying mechanisms which will enable more effective risk stratification and development of potential therapeutic interventions to prevent cancer in CVD patients.

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

The Functional Role of microRNAs and mRNAs in Diabetic Kidney Disease: A Review

Diabetes is a group of diseases marked by poor control of blood glucose levels. Diabetes mellitus (DM) occurs when pancreatic cells fail to make insulin, which is required to keep blood glucose levels stable, disorders, and so on. High glucose levels in the blood induce diabetic effects, which can cause catastrophic damage to bodily organs such as the eyes and lower extremities. Diabetes is classified into many forms, one of which is controlled by hyperglycemia or Diabetic Kidney Disease (DKD), and another that is not controlled by hyperglycemia (nondiabetic kidney disease or NDKD) and is caused by other factors such as hypertension, hereditary. DKD is associated with diabetic nephropathy (DN), a leading cause of chronic kidney disease (CKD) and end-stage renal failure. The disease is characterized by glomerular basement membrane thickening, glomerular sclerosis, and mesangial expansion, resulting in a progressive decrease in glomerular filtration rate, glomerular hypertension, and renal failure or nephrotic syndrome. It is also represented by some microvascular complications such as nerve ischemia produced by intracellular metabolic changes, microvascular illness, and the direct impact of excessive blood glucose on neuronal activity. Therefore, DKD-induced nephrotic failure is worse than NDKD. MicroRNAs (miRNAs) are important in the development and progression of several diseases, including diabetic kidney disease (DKD). These dysregulated miRNAs can impact various cellular processes, including inflammation, fibrosis, oxidative stress, and apoptosis, all of which are implicated during DKD. MiRNAs can alter the course of DKD by targeting several essential mechanisms. Understanding the miRNAs implicated in DKD and their involvement in disease development might lead to identifying possible therapeutic targets for DKD prevention and therapy. Therefore, this review focuses specifically on DKD-associated DN, as well as how in-silico approaches may aid in improving the management of the disease.

Clinical Variables Influence the Ability of miR-101, miR-150, and miR-21 to Predict Ventricular Remodeling after ST-Elevation Myocardial Infarction

Left ventricle remodeling (LVR) after acute myocardial infarction (MI) leads to impairment of both systolic and diastolic function, a significant contributor to heart failure (HF). Despite extensive research in the field, predicting post-MI LVR and HF is still a challenge. Several circulant microRNAs have been proposed as LVR predictors; however, their clinical value is controversial. Here, we used real-time quantitative PCR to quantify the plasma levels of hsa-miR-101, hsa-miR-150, and hsa-miR-21 on the first day of hospital admission of MI patients with ST-elevation (STEMI). We analyzed their correlation to the patient's clinical and paraclinical variables and evaluated their ability to discriminate between post-MI LVR and non-LVR. We show that, despite being excellent MI discriminators, none of these microRNAs can distinguish between LVR and non-LVR patients. Furthermore, we found that diabetes mellitus (DM), Hb level, and the number of erythrocytes significantly influence all three plasma microRNA levels. This suggests that plasma microRNAs' diagnostic and prognostic value in STEMI patients should be reevaluated and interpreted in the context of associated pathologies.

Inhibition of miR-195-3p protects against cardiac dysfunction and fibrosis after myocardial infarction

Cardiac fibrosis following myocardial infarction is a major risk factor for heart failure. Recent evidence suggests that miR-195-3p is up-regulated in fibrotic diseases, including kidney and liver fibrosis. However, its function and underlying mechanisms in cardiac fibrosis after MI remain unknown. To investigate the role of miR-195-3p in MI-induced cardiac fibrosis, we established acute MI models by ligating adult C57B/L6 mice LAD coronary artery while sham-operated mice were used as controls. In vivo inhibition of miR-195-3p was conducted by intramyocardial injection of AAV9-anti-miR-195-3p. In vitro overexpression and inhibition of miR-195-3p were performed by transfecting cultured Cardiac Fibroblasts (CFs) with synthetic miRNA mimic and inhibitor. Our results showed that MI induced the expression of miR-195-3p and that inhibition of miR-195-3p reduced myofibroblast differentiation and collagen deposition and protected cardiac function. In vitro stimulation of CFs with TGF-β1 resulted in a significant increase in miR-195-3p expression. Inhibition of miR-195-3p attenuated the TGF-β1-induced expression of ECM proteins, migration, and proliferation. PTEN expression was significantly reduced in the hearts of MI mice, in activated CFs, and in CFs transfected with miR-195-3p mimic. Inhibition of miR-195-3p markedly restored PTEN expression in MI mice and TGF-β1-treated CFs. In conclusion, this study highlights the crucial role of miR-195-3p in promoting cardiac fibrosis and dysfunction after MI. Inhibiting miR-195-3p could be a promising therapeutic strategy for preventing cardiac fibrosis and preserving cardiac function after MI. Additionally, the study sheds light on the mechanisms underlying the effects of miR-195-3p on fibrosis, including its regulation of PTEN/AKT pathway.

Long Non-coding RNA Involved in the Pathophysiology of Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a prevalent and chronic cardiovascular disorder associated with various pathophysiological alterations, including atrial electrical and structural remodeling, disrupted calcium handling, autonomic nervous system dysfunction, aberrant energy metabolism, and immune dysregulation. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play a significant role in the pathogenesis of AF.

OBJECTIVE

This discussion aims to elucidate the involvement of AF-related lncRNAs, with a specific focus on their role as miRNA sponges that modulate crucial signaling pathways, contributing to the progression of AF. We also address current limitations in AF-related lncRNA research and explore potential future directions in this field. Additionally, we summarize feasible strategies and promising delivery systems for targeting lncRNAs in AF therapy.

CONCLUSION

In conclusion, targeting AF-related lncRNAs holds substantial promise for future investigations and represents a potential therapeutic avenue for managing AF.

Enhancement of Bottle Gourd Oil Activity via Optimized Self-Dispersing Lipid Formulations (SDLFs) to Mitigate Isoproterenol-Evoked Cardiac Toxicity in Rats via Modulating BMP, MMP2, and miRNA-21 and miRNA-23a Genes' Expression

Bottle gourd (BG) oil (family Cucurbitaceae) has several pharmacological activities including a reduction of the hazard of cardiovascular and atherosclerosis conditions. This work aimed to develop and optimize self-dispersing lipid formulations (SDLFs) of BG oil by applying a full 32 factorial design. The formulation variables (oil concentration and surfactant mixture ratio) showed an obvious impact on the characters of the prepared BG-SDLFs including droplet size (DS), polydispersity index (PDI), emulsification time (ET), and transmission percentage (Tr%). The optimum BG-SDLF composed of 30% oil and Tween 80/Cremophor® RH40 (1:1) showed good emulsification characteristics and a better drug release profile compared with BG oil. In vivo study in isoproterenol-injected rats showed that BG oil and the optimized BG-SDLF improved cardiac function, by elevating the miRNA-23a gene expression level and decreasing miRNA-21 gene expression. They also caused the inhibition of the plasma B-type natriuretic peptide (BNP), N-terminal proatrial natriuretic peptide (NT-pro-BNP), cystatin c, galectin-3, lipoprotein-associated phospholipase A2 (Lp-PLA2), matrix metallopeptidase 2 (MMP2), cardiac troponin I (cTnI), and cardiac troponin T (cTnT). Our study demonstrated that BG oil and the optimized BG-SDLF provided a cardioprotection against isoproterenol-induced cardiac toxicity with better results in groups treated with the optimized BG-SDLF.

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.

Bioactive Compounds and Cardiac Fibrosis: Current Insight and Future Prospect

Cardiac fibrosis is a pathological condition characterized by excessive deposition of collagen and other extracellular matrix components in the heart. It is recognized as a major contributor to the development and progression of heart failure. Despite significant research efforts in characterizing and identifying key molecular mechanisms associated with myocardial fibrosis, effective treatment for this condition is still out of sight. In this regard, bioactive compounds have emerged as potential therapeutic antifibrotic agents due to their anti-inflammatory and antioxidant properties. These compounds exhibit the ability to modulate fibrogenic processes by inhibiting the production of extracellular matrix proteins involved in fibroblast to myofibroblast differentiation, or by promoting their breakdown. Extensive investigation of these bioactive compounds offers new possibilities for preventing or reducing cardiac fibrosis and its detrimental consequences. This comprehensive review aims to provide a thorough overview of the mechanisms underlying cardiac fibrosis, address the limitations of current treatment strategies, and specifically explore the potential of bioactive compounds as therapeutic interventions for the treatment and/or prevention of cardiac fibrosis.

Molecular mechanisms of postoperative atrial fibrillation in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) promotes atrial remodeling and fibrosis, providing a substrate for atrial fibrillation (AF). Herein, we investigate the pathophysiological mechanisms of AF in association with OSA in a cohort of cardiac surgery patients. A prospective study including patients undergoing cardiac surgery. Biomarkers reflective of AF pathophysiology (interleukin [IL-6], C-reactive protein [CRP], von Willebrand factor [vWF], N-terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity Troponin T [hs-TnT], and Galectin-3 [Gal-3]) was assessed by functional or immunological assays. miRNAs involved in AF were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Using atrial tissue samples, fibrosis was assessed by Masson's trichrome. Connexin 40 and 43 (Cx40; Cx43) were evaluated by immunolabeling. Fifty-six patients (15 with OSA and 41 non-OSA) were included in this hypothesis-generating pilot study. OSA group had a higher incidence of postoperative AF (POAF) (46.7% vs. 19.5%; p = .042), presented an increased risk of POAF (OR 3.61, 95% CI 1.01-12.92), and had significantly higher baseline levels of NT-proBNP (p = .044), vWF (p = .049), Gal-3 (p = .009), IL-6 (p = .002), and CRP (p = .003). This group presented lower levels of miR-21 and miR-208 (both p < .05). Also, lower Cx40 levels in POAF and/or OSA patients (50.0% vs. 81.8%, p = .033) were found. The presence of interstitial fibrosis (according to myocardial collagen by Masson's trichrome) was raised in OSA patients (86.7% vs. 53.7%, p = .024). Several biomarkers and miRNAs involved in inflammation and fibrosis were dysregulated in OSA patients, which together with a higher degree of interstitial fibrosis, altered miRNA, and Cxs expression predisposes to the development of a substrate that increases the AF risk.

Targeting and delivery of microRNA-targeting antisense oligonucleotides in cardiovascular diseases

Discovered three decades ago, microRNAs (miRNAs) are now recognized as key players in the pathophysiology of multiple human diseases, including those affecting the cardiovascular system. As such, miRNAs have emerged as promising therapeutic targets for preventing the onset and/or progression of several cardiovascular diseases. Anti-miRNA antisense oligonucleotides or "antagomirs" precisely block the activity of specific miRNAs and are therefore a promising therapeutic strategy to repress pathological miRNAs. In this review, we describe advancements in antisense oligonucleotide chemistry that have significantly improved efficacy and safety. Moreover, we summarize recent approaches for the targeted delivery of antagomirs to cardiovascular tissues, highlighting major advantages as well as limitations of viral (i.e., adenovirus, adeno-associated virus, and lentivirus) and non-viral (i.e., liposomes, extracellular vesicles, and polymer nanoparticles) delivery systems. We discuss recent preclinical studies that use targeted antagomir delivery systems to treat three major cardiovascular diseases (atherosclerosis, myocardial infarction, and cardiac hypertrophy, including hypertrophy caused by hypertension), highlighting therapeutic results and discussing challenges that limit clinical applicability.

Is miR-21 A Therapeutic Target in Cardiovascular Disease?

microRNA-21 (miR-21) serves a multitude of functions at the molecular level through its regulation of messenger RNA. Previous research has sparked interest in the role of miR-21 as a potential therapeutic target in cardiovascular diseases. miR-21 expression contributes to the differentiation, proliferation, and maturation of many cell types, such as fibroblasts, endothelial cells, cardiomyocytes, and endothelial progenitor cells. The function of miR-21 depends upon its expression level in the specific cell types and downstream targets, which determine cell fate. Under pathological conditions, the expression level of miR-21 is altered, leading to abnormal gene regulation of downstream signaling and cardiovascular diseases such as hypertension, cardiac hypertrophy and fibrosis, atherosclerosis, and heart failure. Agomirs or antagomirs can be introduced into the respective tissue type to reverse or stop the progression of the disease. Exosomes in the extracellular vesicles, which mediate many cellular events with high biocompatibility, have a high potential of efficiently delivering miR-21 to their targeted cells. The critical role of miR-21 in cardiovascular disease (CVD) is indisputable, but there are controversial reports on the function of miR-21 in the same disease. This discrepancy sparks interest in better understanding the role of miR-21 in different tissues under different stages of various diseases and the mechanism of how miR-21 inhibitors work.

MicroRNA in the Diagnosis and Treatment of Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX), a broad-spectrum chemotherapy drug, is widely applied to the treatment of cancer; however, DOX-induced cardiotoxicity (DIC) limits its clinical therapeutic utility. However, it is difficult to monitor and detect DIC at an early stage using conventional detection methods. Thus, sensitive, accurate, and specific methods of diagnosis and treatment are important in clinical practice. MicroRNAs (miRNAs) belong to non-coding RNAs (ncRNAs) and are stable and easy to detect. Moreover, miRNAs are expected to become biomarkers and therapeutic targets for DIC; thus, there are currently many studies focusing on the role of miRNAs in DIC. In this review, we list the prominent studies on the diagnosis and treatment of miRNAs in DIC, explore the feasibility and difficulties of using miRNAs as diagnostic biomarkers and therapeutic targets, and provide recommendations for future research.

Activated fibroblasts in cardiac and cancer fibrosis: An overview of analogies and new potential therapeutic options

Heart disease and cancer are two major causes of morbidity and mortality in the industrialized countries, and their increasingly recognized connections are shifting the focus from single disease studies to an interdisciplinary approach. Fibroblast-mediated intercellular crosstalk is critically involved in the evolution of both pathologies. In healthy myocardium and in non-cancerous conditions, resident fibroblasts are the main cell source for synthesis of the extracellular matrix (ECM) and important sentinels of tissue integrity. In the setting of myocardial disease or cancer, quiescent fibroblasts activate, respectively, into myofibroblasts (myoFbs) and cancer-associated fibroblasts (CAFs), characterized by increased production of contractile proteins, and by a highly proliferative and secretory phenotype. Although the initial activation of myoFbs/CAFs is an adaptive process to repair the damaged tissue, massive deposition of ECM proteins leads to maladaptive cardiac or cancer fibrosis, a recognized marker of adverse outcome. A better understanding of the key mechanisms orchestrating fibroblast hyperactivity may help developing innovative therapeutic options to restrain myocardial or tumor stiffness and improve patient prognosis. Albeit still unappreciated, the dynamic transition of myocardial and tumor fibroblasts into myoFbs and CAFs shares several common triggers and signaling pathways relevant to TGF-β dependent cascade, metabolic reprogramming, mechanotransduction, secretory properties, and epigenetic regulation, which might lay the foundation for future antifibrotic intervention. Therefore, the aim of this review is to highlight emerging analogies in the molecular signature underlying myoFbs and CAFs activation with the purpose of identifying novel prognostic/diagnostic biomarkers, and to elucidate the potential of drug repositioning strategies to mitigate cardiac/cancer fibrosis.

An updated review on cell signaling pathways regulated by candidate miRNAs in coronary artery disease

MicroRNAs (miRNAs) are small endogenous non-coding RNA, size range from 17 to 25 nucleotides that regulate gene expression at the post-transcriptional level. More than 2000 different types of miRNAs have been identified in humans which regulate about 60% of gene expression, since the discovery of the first miRNA in 1993. MicroRNA performs many functions such as being involved in the regulation of various biological pathways for example cell migration, cell proliferation, cell differentiation, disease progression, and initiation. miRNAs also play an important role in the development of atherosclerosis lesions, cardiac fibroblast, cardiac hypertrophy, cancer, and neurological disorders. Abnormal activation of many cell signaling pathways has been observed in the development of coronary artery disease. Abnormal expression of these candidate miRNA genes leads to up or downregulation of specific genes, these specific genes play an important role in the regulation of cell signaling pathways involved in coronary artery disease. Many studies have found that miRNAs play a key role in the regulation of crucial signaling pathways that are involved in the pathophysiology of coronary artery disease. This review is designed to investigate the role of cell signaling pathways regulated by candidate miRNAs in Coronary artery disease.

Low expression of miR-1929-3p mediates murine cytomegalovirus-induced fibrosis in cardiac fibroblasts via targeting endothelin a receptor/NLRP3 inflammasome pathway

MicroRNAs are crucial in the development of myocardial remodeling in hypertension. Low miR-1929-3p expression induced by murine cytomegalovirus (MCMV) infection is closely related to hypertensive myocardial remodeling. This study investigated the molecular mechanism of miR-1929-3p-induced myocardial remodeling after MCMV infection. We modeled MCMV-infected mouse cardiac fibroblasts (MMCFs) as the primary cell model. First, MCMV infection reduced the expression of miR-1929-3p and increased the mRNA and protein expression of its target gene endothelin receptor type A (ETAR) in mouse cardiac fibroblasts (MCFs), which demonstrated an internal relationship with myocardial fibrosis (MF) based on high proliferation, phenotypic transformation (α-SMA), and collagen expression in MMCFs. The transfection of the miR-1929-3p mimic downregulated the high expression of ETAR and alleviated these adverse effects in MMCFs. Inversely, these effects were exacerbated by the miR-1929-3p inhibitor. Second, the transfection of endothelin receptor type A over-expressed adenovirus (adETAR) reversed these positive effects of the miR-1929-3p mimic on MF improvement. Third, the transfection of adETAR exhibited a strong inflammatory response in MMCFs with increased expression of NOD-like receptors pyrin domain containing 3 (NLRP3) and increased secretion of interleukin-18. However, we found that the ETAR antagonist BQ123 and the selected NLRP3 inflammasome inhibitor MCC950 effectively eliminated the inflammatory response induced by both MCMV infection and miR-1929-3p inhibitor. Moreover, the MCF supernatant was related to cardiomyocyte hypertrophy. Our findings suggest that MCMV infection promotes MF by inducing the downregulation of miR-1929-3p and the high expression of ETAR, which activates NLRP3 inflammasomes in MCFs.

MicroRNA-21 mediated cross-talk between cardiomyocytes and fibroblasts in patients with atrial fibrillation

Background

Atrial fibrosis represents a major hallmark in disease progression of atrial fibrillation (AF). We have previously shown that circulating microRNA-21 (miR-21) correlates with the extent of left atrial fibrosis in patients undergoing catheter ablation for AF and can serve as a biomarker to predict ablation success. In this study, we aimed to validate the role of miR-21-5p as a biomarker in a large cohort of AF patients and to investigate its pathophysiological role in atrial remodeling.

Methods

For the validation cohort, we included 175 patients undergoing catheter ablation for AF. Bipolar voltage maps were obtained, circulating miR-21-5p was measured, and patients were followed-up for 12  months including ECG holter monitoring. AF was simulated by tachyarrhythmic pacing of cultured cardiomyocytes, the culture medium was transferred to fibroblast, and fibrosis pathways were analysed.

Results

73.3% of patients with no/minor LVAs, 51.4% of patients with moderate LVAs and only 18.2% of patients with extensive LVAs were in stable sinus rhythm (SR) 12  months after ablation (p < 0.01). Circulating miR-21-5p levels significantly correlated with the extent of LVAs and event-free survival. In-vitro tachyarrhythmic pacing of HL-1 cardiomyocytes resulted in an increased miR-21-5p expression. Transfer of the culture medium to fibroblasts induced fibrosis pathways and collagen production. The HDAC1 inhibitor mocetinostat was found to inhibit atrial fibrosis development.

Conclusion

We validated miR-21-5p as a biomarker that reflects the extent of left atrial fibrosis in AF patients. Furthermore, we found that miR-21-5p is released in-vitro from cardiomyocytes under tachyarrhythmic conditions and stimulates fibroblasts in a paracrine mode to induce collagen production.

Inducible miR-1224 silences cerebrovascular Serpine1 and restores blood flow to the stroke-affected site of the brain

The α-tocotrienol (TCT) form of natural vitamin E is more potent than the better known α-tocopherol against stroke. Angiographic studies of canine stroke have revealed beneficial cerebrovascular effects of TCT. This work seeks to understand the molecular basis of such effect. In mice, TCT supplementation improved perfusion at the stroke-affected site by inducing miR-1224. miRNA profiling of a laser-capture-microdissected stroke-affected brain site identified miR-1224 as the only vascular miR induced. Lentiviral knockdown of miR-1224 significantly blunted the otherwise beneficial effects of TCT on stroke outcomes. Studies on primary brain microvascular endothelial cells revealed direct angiogenic properties of miR-1224. In mice not treated with TCT, advance stereotaxic delivery of an miR-1224 mimic to the stroke site markedly improved stroke outcomes. Mechanistic studies identified Serpine1 as a target of miR-1224. Downregulation of Serpine1 augmented the angiogenic response of the miR-1224 mimic in the brain endothelial cells. The inhibition of Serpine1, by dietary TCT and pharmacologically, increased cerebrovascular blood flow at the stroke-affected site and protected against stroke. This work assigns Serpine1, otherwise known to be of critical significance in stroke, a cerebrovascular function that worsens stroke outcomes. miR-1224-dependent inhibition of Serpine1 can be achieved by dietary TCT as well as by the small-molecule inhibitor TM5441.

MicroRNAs in Cancer and Cardiovascular Disease

Although cardiac tumor formation is rare, accumulating evidence suggests that the two leading causes of deaths, cancers, and cardiovascular diseases are similar in terms of pathogenesis, including angiogenesis, immune responses, and fibrosis. These similarities have led to the creation of new exciting field of study called cardio-oncology. Here, we review the similarities between cancer and cardiovascular disease from the perspective of microRNAs (miRNAs). As miRNAs are well-known regulators of translation by binding to the 3'-untranslated regions (UTRs) of messenger RNAs (mRNAs), we carefully dissect how a specific set of miRNAs are both oncomiRs (miRNAs in cancer) and myomiRs (muscle-related miRNAs). Furthermore, from the standpoint of similar pathogenesis, miRNAs categories related to the similar pathogenesis are discussed; namely, angiomiRs, Immune-miRs, and fibromiRs.

Sodium hydrosulfide and bone marrow derived mesenchymal stem cells combined therapy for bleomycin induced pulmonary fibrosis in rats: Implication of micro RNA-21 and Lnc GAS5

AIMS

Pulmonary fibrosis (PF) is considered as an end stage for many lung diseases. Mesenchymal stem cells (MSC) as regenerative therapy have become a remarkably valuable therapeutic strategy in different diseases. Hydrogen sulfide has been recently introduced into the medical field for its antifibrotic properties in addition to enhancement of MSC stemness and function. The aim of the present study was to investigate the ability of BM-MSC in combination with NaHS to attenuate Bleomycin induced pulmonary fibrosis was studied in rats. A special emphasis was given to miR-21 and GAS5 as important players in the development of PF.

MAIN METHODS

PF was induced in 32 Wistar male rats by single endotracheal injection of bleomycin, those were randomly divided into four groups (8 rats each): (untreated PF group) - (PF + MSC) treated group- (PF + NaHS treated group) - PF + combined (NAHS + MSC) treated group.

KEY FINDINGS

Induction of PF was associated with increased miR-21 and decreased lncRNA-GAS5 expression. Treatment with either NaHS or BM-MSC leads to an inhibitory effect on pulmonary fibrosis as evidenced by improvement of histopathological studies, pulmonary function tests, reduction of inflammatory and fibrotic markers like Hydroxyproline, TNF α, TGF-β and caspase -3 together with downregulation miR-21 and increase lncRNA-GAS5 expression.

SIGNIFICANCE

The current work revealed the inhibitory effect of combined NaHS and BM-MSC on pulmonary fibrosis with concomitant modulation of miR-21 and lncRNA-GAS5 expression.

Revisiting miRNA-21 as a Therapeutic Strategy for Myocardial Infarction: A Systematic Review

Several types of cardiovascular cells use microRNA-21 ( miR-21 ), which has been linked to cardioprotection. In this study, we systematically reviewed the results of published papers on the therapeutic effect of miR-21 for myocardial infarction. Studies described the cardioprotective effects of miR-21 to reduce infarct size by improving angiogenesis, antiapoptotic, and anti-inflammatory mechanisms. Results suggest that cardioprotective effects of miR-21 may work synergistically to prevent the deterioration of cardiac function during postischemia. However, there are other results that indicate that miR-21 positively regulates tissue fibrosis, potentially worsening a postischemic injury. The dual functionalities of miR-21 occur through the targeting of genes and signaling pathways, such as PTEN , PDCD4 , KBTBD7 , NOS3 , STRN , and Spry-1 . This review provides insights into the future advancement of safe miR-21 -based genetic therapy in the treatment of myocardial infarction.

Non-coding RNAs: Important participants in cardiac fibrosis

Cardiac remodeling is a pathophysiological process activated by diverse cardiac stress, which impairs cardiac function and leads to adverse clinical outcome. This remodeling partly attributes to cardiac fibrosis, which is a result of differentiation of cardiac fibroblasts to myofibroblasts and the production of excessive extracellular matrix within the myocardium. Non-coding RNAs mainly include microRNAs and long non-coding RNAs. These non-coding RNAs have been proved to have a profound impact on biological behaviors of various cardiac cell types and play a pivotal role in the development of cardiac fibrosis. This review aims to summarize the role of microRNAs and long non-coding RNAs in cardiac fibrosis associated with pressure overload, ischemia, diabetes mellitus, aging, atrial fibrillation and heart transplantation, meanwhile shed light on the diagnostic and therapeutic potential of non-coding RNAs for cardiac fibrosis.

Epi-Drugs in Heart Failure

Unveiling the secrets of genome's flexibility does not only foster new research in the field, but also gives rise to the exploration and development of novel epigenetic-based therapies as an approach to alleviate disease phenotypes. A better understanding of chromatin biology (DNA/histone complexes) and non-coding RNAs (ncRNAs) has enabled the development of epigenetic drugs able to modulate transcriptional programs implicated in cardiovascular diseases. This particularly applies to heart failure, where epigenetic networks have shown to underpin several pathological features, such as left ventricular hypertrophy, fibrosis, cardiomyocyte apoptosis and microvascular dysfunction. Targeting epigenetic signals might represent a promising approach, especially in patients with heart failure with preserved ejection fraction (HFpEF), where prognosis remains poor and breakthrough therapies have yet to be approved. In this setting, epigenetics can be employed for the development of customized therapeutic approaches thus paving the way for personalized medicine. Even though the beneficial effects of epi-drugs are gaining attention, the number of epigenetic compounds used in the clinical practice remains low suggesting that more selective epi-drugs are needed. From DNA-methylation changes to non-coding RNAs, we can establish brand-new regulations for drug targets with the aim of restoring healthy epigenomes and transcriptional programs in the failing heart. In the present review, we bring the timeline of epi-drug discovery and development, thus highlighting the emerging role of epigenetic therapies in heart failure.

MicroRNAs (miRNAs) in Cardiovascular Complications of Rheumatoid Arthritis (RA): What Is New?

Rheumatoid Arthritis (RA) is among the most prevalent and impactful rheumatologic chronic autoimmune diseases (AIDs) worldwide. Within a framework that recognizes both immunological activation and inflammatory pathways, the exact cause of RA remains unclear. It seems however, that RA is initiated by a combination between genetic susceptibility, and environmental triggers, which result in an auto-perpetuating process. The subsequently, systemic inflammation associated with RA is linked with a variety of extra-articular comorbidities, including cardiovascular disease (CVD), resulting in increased mortality and morbidity. Hitherto, vast evidence demonstrated the key role of non-coding RNAs such as microRNAs (miRNAs) in RA, and in RA-CVD related complications. In this descriptive review, we aim to highlight the specific role of miRNAs in autoimmune processes, explicitly on their regulatory roles in the pathogenesis of RA, and its CV consequences, their main role as novel biomarkers, and their possible role as therapeutic targets.

Insight into the Role of the PI3K/Akt Pathway in Ischemic Injury and Post-Infarct Left Ventricular Remodeling in Normal and Diabetic Heart

Despite the significant decline in mortality, cardiovascular diseases are still the leading cause of death worldwide. Among them, myocardial infarction (MI) seems to be the most important. A further decline in the death rate may be achieved by the introduction of molecularly targeted drugs. It seems that the components of the PI3K/Akt signaling pathway are good candidates for this. The PI3K/Akt pathway plays a key role in the regulation of the growth and survival of cells, such as cardiomyocytes. In addition, it has been shown that the activation of the PI3K/Akt pathway results in the alleviation of the negative post-infarct changes in the myocardium and is impaired in the state of diabetes. In this article, the role of this pathway was described in each step of ischemia and subsequent left ventricular remodeling. In addition, we point out the most promising substances which need more investigation before introduction into clinical practice. Moreover, we present the impact of diabetes and widely used cardiac and antidiabetic drugs on the PI3K/Akt pathway and discuss the molecular mechanism of its effects on myocardial ischemia and left ventricular remodeling.

Suppression of lncRNA Gm47283 attenuates myocardial infarction via miR-706/ Ptgs2/ferroptosis axis

Myocardial infarction (MI) is the leading cause of sudden death. Long non-doing RNAs (lncRNAs) were demonstrated to play crucial roles in multiple diseases, including cancer and cardiovascular diseases. Nevertheless, the molecular mechanism of lncNRAs in MI is unclear. In this study, we integrated bioinformatics and molecular biological experiments to identify the novel lncRNA transcripts and elucidated its regulatory mechanism in MI. First, we identified 10 dysregualted lncRNAs and found that lncRNA Gm47283 was the top risk factor in MI. Bioinformatics analysis predicted that lncRNA Gm47283 exerted function via targeting miR-706 and Ptgs2. Ptgs2 was also the known regulator of ferroptosis. Inhibition or overexpression of lncRNA Gm47283 could regulate Ptgs2 expression and downstream ferroptosis activity. Overexpression of miR-706 could inhibit the expression of Ptgs2 and the activity of ferroptosis, thereby attenuated cellular injury. Mechanically, co-transfection experiments showed that overexpression of miR-706 could reverse the damage effect that was caused by lncRNA Gm47283 overexpression, via inhibiting Ptgs2 and ferroptosis. Additionally, inhibition of lncRNA Gm47283 by stem cell membrane coated siRNA could attenuate MI in vivo. Our study elucidated a novel mechanism containing lncRNA Gm47283/miR-706/Ptgs2/ferroptosis in MI, which provided a potential therapeutic for MI.

Graphical Abstract. Stem cell membrane coated siRNA of lncRNA Gm47283 inhibits cardiomyocyte ferroptosis in myocardial infarction rat. Stem cell membrane-coated siRNA of lncRNA Gm47283 increases miR-706, and then miR-706 suppresses the expression of Ptgs2 to reduce lipid peroxidation toxicity, and then inhibits cardiomyocyte ferroptosis. PUFA: polyunsaturated fatty acid.

MicroRNAs and Efferocytosis: Implications for Diagnosis and Therapy

About 10-100 billion cells are generated in the human body in a day, and accordingly, 10-100 billion cells predominantly die for maintaining homeostasis. Dead cells generated by apoptosis are also rapidly engulfed by macrophages (Mθs) to be degraded. In case of the inefficient engulfment of apoptotic cells (ACs) via Mθs, they experience secondary necrosis and thus release intracellular materials, which display damage-associated molecular patterns (DAMPs) and result in diseases. Over the last decades, researchers have also reflected on the significant contribution of microRNAs (miRNAs) to autoimmune diseases through the regulation of Mθs functions. Moreover, miRNAs have shown intricate involvement with completely adjusting basic Mθs functions, such as phagocytosis, inflammation, efferocytosis, tumor promotion, and tissue repair. In this review, the mechanism of efferocytosis containing "Find-Me", "Eat-Me", and "Digest-Me" signals is summarized and the biogenesis of miRNAs is briefly described. Finally, the role of miRNAs in efferocytosis is discussed. It is concluded that miRNAs represent promising treatments and diagnostic targets in impaired phagocytic clearance, which leads to different diseases.

First-Trimester Screening for Fetal Growth Restriction and Small-for-Gestational-Age Pregnancies without Preeclampsia Using Cardiovascular Disease-Associated MicroRNA Biomarkers

The goal of the study was to determine the early diagnostical potential of cardiovascular disease-associated microRNAs for prediction of small-for-gestational-age (SGA) and fetal growth restriction (FGR) without preeclampsia (PE). The whole peripheral venous blood samples were collected within 10 to 13 weeks of gestation from singleton Caucasian pregnancies within the period November 2012 to March 2020. The case-control retrospective study, nested in a cohort, involved all pregnancies diagnosed with SGA (n = 37) or FGR (n = 82) without PE and 80 appropriate-for-gestational age (AGA) pregnancies selected with regard to equality of sample storage time. Gene expression of 29 cardiovascular disease-associated microRNAs was assessed using real-time RT-PCR. Upregulation of miR-16-5p, miR-20a-5p, miR-146a-5p, miR-155-5p, miR-181a-5p, and miR-195-5p was observed in SGA or FGR pregnancies at 10.0% false positive rate (FPR). Upregulation of miR-1-3p, miR-20b-5p, miR-126-3p, miR-130b-3p, and miR-499a-5p was observed in SGA pregnancies only at 10.0% FPR. Upregulation of miR-145-5p, miR-342-3p, and miR-574-3p was detected in FGR pregnancies at 10.0% FPR. The combination of four microRNA biomarkers (miR-1-3p, miR-20a-5p, miR-146a-5p, and miR-181a-5p) was able to identify 75.68% SGA pregnancies at 10.0% FPR in early stages of gestation. The detection rate of SGA pregnancies without PE increased 4.67-fold (75.68% vs. 16.22%) when compared with the routine first-trimester screening for PE and/or FGR based on the criteria of the Fetal Medicine Foundation. The combination of seven microRNA biomarkers (miR-16-5p, miR-20a-5p, miR-145-5p, miR-146a-5p, miR-181a-5p, miR-342-3p, and miR-574-3p) was able to identify 42.68% FGR pregnancies at 10.0% FPR in early stages of gestation. The detection rate of FGR pregnancies without PE increased 1.52-fold (42.68% vs. 28.05%) when compared with the routine first-trimester screening for PE and/or FGR based on the criteria of the Fetal Medicine Foundation. Cardiovascular disease-associated microRNAs represent promising early biomarkers with very suitable predictive potential for SGA or FGR without PE to be implemented into the routine screening programs.

Non-canonical features of microRNAs: paradigms emerging from cardiovascular disease

Research showing that microRNAs (miRNAs) are versatile regulators of gene expression has instigated tremendous interest in cardiovascular research. The overwhelming majority of studies are predicated on the dogmatic notion that miRNAs regulate the expression of specific target mRNAs by inhibiting mRNA translation or promoting mRNA decay in the RNA-induced silencing complex (RISC). These efforts mostly identified and dissected contributions of multiple regulatory networks of miRNA-target mRNAs to cardiovascular pathogenesis. However, evidence from studies in the past decade indicates that miRNAs also operate beyond this canonical paradigm, featuring non-conventional regulatory functions and cellular localizations that have a pathophysiological role in cardiovascular disease. In this Review, we highlight the functional relevance of atypical miRNA biogenesis and localization as well as RISC heterogeneity. Moreover, we delineate remarkable non-canonical examples of miRNA functionality, including direct interactions with proteins beyond the Argonaute family and their role in transcriptional regulation in the nucleus and in mitochondria. We scrutinize the relevance of non-conventional biogenesis and non-canonical functions of miRNAs in cardiovascular homeostasis and pathology, and contextualize how uncovering these non-conventional properties can expand the scope of translational research in the cardiovascular field and beyond.

The Interplay Between Gut Microbiota and miRNAs in Cardiovascular Diseases

The human microbiota contains microorganisms found on the skin, mucosal surfaces and in other tissues. The major component, the gut microbiota, can be influenced by diet, genetics, and environmental factors. Any change in its composition results in pathophysiological changes that can further influence the evolution of different conditions, including cardiovascular diseases (CVDs). The microbiome is a complex ecosystem and can be considered the metagenome of the microbiota. MicroRNAs (miRNAs) are speculated to interact with the intestinal microbiota for modulating gene expressions of the host. miRNAs represent a category of small non-coding RNAs, consisting of approximately 22 nucleotides, which can regulate gene expression at post-transcriptional level, by influencing the degradation of mRNA and modifying protein amounts. miRNAs display a multitude of roles, being able to influence the pathogenesis and progression of various diseases. Circulating miRNAs are stable against degradation, due to their enclosure into extracellular vesicles (EVs). This review aims to assess the current knowledge of the possible interactions between gut microbiota, miRNAs, and CVDs. As more scientific research is conducted, it can be speculated that personalized patient care in the future may include the management of gut microbiota composition and the targeted treatment against certain expression of miRNAs.

MicroRNA-21-5p acts via the PTEN/Akt/FOXO3a signaling pathway to prevent cardiomyocyte injury caused by high glucose/high fat conditions

MicroRNAs (miRNAs or miRs) play important roles in cardiovascular disease. miR-21-5p is known to be involved in the regulation of cardiomyocyte injury under high glucose and high fat (HG-HF) conditions, but its mechanism of action remains unclear. In the present study, a cardiomyocyte cell line, H9c2, was treated with 33 mM glucose and 250 µM sodium palmitate for 24, 48, and 72 h to produce HG-HF injury. After treatment, miR-21-5p expression was detected by reverse transcription-quantitative PCR. A miR-21-5p mimic was then constructed and transfected into the cells and the potential molecular mechanism was investigated using Cell Counting Kit-8, TUNEL, flow cytometry and western blot assays. Expression of miR-21-5p was significantly downregulated by HG-HF treatment of H9c2 cells for 24, 48, and 72 h. In subsequent experiments, cells were treated for an intermediate period (48 h). Compared with the control group, HG-HF treatment significantly inhibited H9c2 proliferation and promoted apoptosis, while these effects were significantly reduced in the miR-21-5p mimic. Compared with the control group, HG-HF treatment significantly increased reactive oxygen species, while miR-21-5p mimic significantly reduced this effect. Compared with the control group, HG-HF treatment significantly increased the expression of the pro-apoptotic proteins Bax and phosphorylated (p)-Akt and decreased the expression of the anti-apoptotic proteins Bcl-2, p-PTEN, and p-FOXO3a, while overexpression of miR-21-5p significantly reduced these effects. The results revealed that miR-21-5p inhibited apoptosis and oxidative stress in H9c2 cells induced by HG-HF, likely through the PTEN/Akt/FOXO3a signaling pathway.

Sporadic Alzheimer's Disease- and Neurotoxicity-Related microRNAs Affecting Key Events of Tau-Driven Adverse Outcome Pathway Toward Memory Loss

BACKGROUND

A complex network of aging-related homeostatic pathways that are sensitive to further deterioration in the presence of genetic, systemic, and environmental risk factors, and lifestyle, is implicated in the pathogenesis of progressive neurodegenerative diseases, such as sporadic (late-onset) Alzheimer's disease (sAD).

OBJECTIVE

Since sAD pathology and neurotoxicity share microRNAs (miRs) regulating common as well as overlapping pathological processes, environmental neurotoxic compounds are hypothesized to exert a risk for sAD initiation and progression.

METHODS

Literature search for miRs associated with human sAD and environmental neurotoxic compounds was conducted. Functional miR analysis using PathDip was performed to create miR-target interaction networks.

RESULTS

The identified miRs were successfully linked to the hypothetical starting point and key events of the earlier proposed tau-driven adverse outcome pathway toward memory loss. Functional miR analysis confirmed most of the findings retrieved from literature and revealed some interesting findings. The analysis identified 40 miRs involved in both sAD and neurotoxicity that dysregulated processes governing the plausible adverse outcome pathway for memory loss.

CONCLUSION

Creating miR-target interaction networks related to pathological processes involved in sAD initiation and progression, and environmental chemical-induced neurotoxicity, respectively, provided overlapping miR-target interaction networks. This overlap offered an opportunity to create an alternative picture of the mechanisms underlying sAD initiation and early progression. Looking at initiation and progression of sAD from this new angle may open for new biomarkers and novel drug targets for sAD before the appearance of the first clinical symptoms.

A new player in the game: treatment with antagomiR-21a-5p significantly attenuates histological and echocardiographic effects of experimental autoimmune myocarditis

AIMS

Myocarditis is associated with formidable symptoms and increased risk of adverse outcomes. Current approaches mostly rely on symptomatic treatments, warranting novel concepts for clinical practice. The aim of this study was to investigate the microRNA (miRNA) expression profile of Balb/c mice with experimental autoimmune myocarditis (EAM), choose a representative miRNA to antagonize after review of available literature and test its effects on myocardial inflammation in vitro and in vivo.

METHODS AND RESULTS

Phase 1: EAM was induced in 12 male Balb/c mice, 10 animals served as controls. After sacrifice, next-generation sequencing (NGS) of the miRNA expression profile was performed. Based on these results, H9C2 cells and human ventricular cardiac fibroblasts exposed to lipopolysaccharide (LPS) were treated with the selected candidate antagomiR-21a-5p. Phase 2: EAM was induced in 48 animals. Thereof, 24 animals were either treated with antagomiR-21a-5p or negative control oligonucleotide in a nanoparticle formulation. Transthoracic echocardiography (TTE) was performed on Days 0, 7, 14, and 21. Histopathological examination was performed after sacrifice. Phase 1: EAM resulted in a significant up-regulation of 27 miRNAs, including miR-21a-5p (log2FC: 2.23, adj. P = 0.0026). Transfection with antagomiR-21a-5p resulted in a significant reduction of TNFα, IL-6, and collagen I in vitro. Phase 2: Treatment with antagomiR-21a-5p, formulated in polymeric nanoparticles for systemic injection, significantly attenuated myocardial inflammation (P = 0.001) and fibrosis (P = 0.013), as well as myocardial 'hypertrophy' on TTE.

CONCLUSIONS

Silencing of miR-21a-5p results in a significant reduction of the expression of pro-inflammatory cytokines in vitro, as well as a significant attenuation of inflammation, fibrosis and echocardiographic effects of EAM in vivo.

Exosomes in cardiovascular diseases: a blessing or a sin for the mankind

Cardiovascular diseases (CVDs) comprises disorders of blood vessels and heart. Multiple cells in the heart suggests that hetero-cellular communication, which is an important aspect in heart functioning and there is a need to elucidate the way in which this inter-cellular communication occurs. Now a days, exosomal research has gained much attention. Exosomes, nano-shuttles, are EVs with diameters ranging from 40 to 160 nm (average 100 nm), secreted by body cells. These vesicles act as cell-to-cell communicators and are carriers of important biomolecules such as RNAs, miRNAs, Proteins and lipids. Exosomes can change the gene expression of the recipient cells, thereby, changes the cellular characteristics. Exosomes have known to play an essential role in protection as well as progression of various cardiovascular diseases. In the present review, role of exosomes in various CVDs have been discussed.

Plasma miR-21 as a potential predictor in prediabetic individuals with a positive family history of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a heritable metabolic perturbation, rapidly growing across the world. Primary recognition of susceptible individuals with a family history of type 2 diabetes (FHD) in the prediabetes stage could delay the onset of T2DM or reduce complications induced by diabetes. This study aims to evaluate the expression levels of miR-21, miR-126 as noninvasive predictive biomarkers in individuals with genetic predisposition and investigate the correlation of miRNAs and cardiometabolic risk factors. Our study demonstrated that miR-21 expression has a notable elevate in both groups of T2DM and pre-T2DM. miR-21 expression was distinguished in the pre-T2DM and T2DM from the nondiabetic individuals by ROC curve analysis with AUC of 0.77 (95% CI 0.65-0.90; p = 0.0004) and AUC of 0.78 (95% CI 0.64-0.92; p = 0.0042), respectively. The relative gene expression of miR-126 was nearly equal among groups. miR-21 expression was positively associated with glycosylated hemoglobin (HbA1c), fasting blood sugar (FBS), and triglyceride (TG) and might have diagnostic value for T2DM and pre-T2DM. This study has revealed that the expression level of miR-21 can be considered as a non-invasive and rapid tool for distinguishing pre-T2DM and T2DM counterparts from healthy individuals.

Diagnostic and Prognostic Value of miRNAs after Coronary Artery Bypass Grafting: A Review

MiRNAs are noncoding, 21-24 nucleotide-long RNA particles that control over 60% of genes. MiRNAs affect gene expression through binding to the 3'-untranslated region of messenger RNA (mRNA), thus inhibiting mRNA translation or inducing mRNA degradation. MiRNAs have been associated with various cardiovascular diseases, including heart failure, hypertension, left ventricular hypertrophy, or ischemic heart disease. In addition, miRNA expression alters during coronary artery bypass grafting (CABG) surgery, which could be used to predict perioperative outcomes. CABG is an operation in which complex coronary arteries stenosis is treated by bypassing atherosclerotic lesions with venous or arterial grafts. Despite a very low perioperative mortality rate and excellent long-term survival, CABG is associated with postoperative complications, including reperfusion injury, graft failure, atrial fibrillation and perioperative myocardial infarction. So far, no reliable diagnostic and prognostic tools to predict prognosis after CABG have been developed. Changes in the perioperative miRNA expression levels could improve the diagnosis of post-CABG myocardial infarction and atrial fibrillation and could be used to stratify risk after CABG. Herein, we describe the expression changes of different subtypes of miRNAs during CABG and review the diagnostic and prognostic utility of miRNAs in patients undergoing CABG.

MicroRNAs as Biomarkers and Therapeutic Targets in Doxorubicin-Induced Cardiomyopathy: A Review

Doxorubicin is a broad-spectrum chemotherapy drug applied in antitumor therapy. However, its clinical utility is limited by its fatal cardiotoxicity. Doxorubicin (DOX)-induced cardiomyopathy (DIC) begins with the first DOX dose and is characterized by being cumulative dose-dependent, and its early diagnosis using common detection methods is very difficult. Therefore, it is urgent to determine the underlying mechanism of DIC to construct treatment strategies for the early intervention before irreversible damage to the myocardium occurs. Growing evidence suggests that microRNAs (miRNAs) play regulatory roles in the cardiovascular system. miRNAs may be involved in DIC by acting through multiple pathways to induce cardiomyocyte injury. Recent studies have shown that the dysregulation of miRNA expression can aggravate the pathological process of DIC, including the induction of oxidative stress, apoptosis, ion channel dysfunction and microvascular dysfunction. Current findings on the roles of miRNAs in DIC have led to a wide range of studies exploring candidate miRNAs to be utilized as diagnostic biomarkers and potential therapeutic targets for DIC. In this review, we discuss frontier studies on the roles of miRNAs in DIC to better understand their functions, develop relevant applications in DIC, discuss possible reasons for the limitations of their use and speculate on innovative treatment strategies.

miR-21 in Human Cardiomyopathies

miR-21 is a 22-nucleotide long microRNA that matches target mRNAs in a complementary base pairing fashion and regulates gene expression by repressing or degrading target mRNAs. miR-21 is involved in various cardiomyopathies, including heart failure, dilated cardiomyopathy, myocardial infarction, and diabetic cardiomyopathy. Expression levels of miR-21 notably change in both heart and circulation and provide cardiac protection after heart injury. In the meantime, miR-21 also tightly links to cardiac dysfunctions such as cardiac hypertrophy and fibrosis. This review focuses on the miR-21 expression pattern and its functions in diseased-heart and further discusses the feasibility of miR-21 as a biomarker and therapeutic target in cardiomyopathies.

Carbon nanodot-based electrogenerated chemiluminescence biosensor for miRNA-21 detection

A simple carbon nanodot–based electrogenerated chemiluminescence biosensor is described for sensitive and selective detection of microRNA-21 (miRNA-21), a biomarker of several pathologies including cardiovascular diseases (CVDs). The photoluminescent carbon nanodots (CNDs) were obtained using a new synthesis method, simply by treating tiger nut milk in a microwave reactor. The synthesis is environmentally friendly, simple, and efficient. The optical properties and morphological characteristics of the CNDs were exhaustively investigated, confirming that they have oxygen and nitrogen functional groups on their surfaces and exhibit excitation-dependent fluorescence emission, as well as photostability. They act as co-reactant agents in the anodic electrochemiluminescence (ECL) of [Ru(bpy)₃]²⁺, producing different signals for the probe (single-stranded DNA) and the hybridized target (double-stranded DNA). These results paved the way for the development of a sensitive ECL biosensor for the detection of miRNA-21. This was developed by immobilization of a thiolated oligonucleotide, fully complementary to the miRNA-21 sequence, on the disposable gold electrode. The target miRNA-21 was hybridized with the probe on the electrode surface, and the hybridization was detected by the enhancement of the [Ru(bpy)₃]²⁺/DNA ECL signal using CNDs. The biosensor shows a linear response to miRNA-21 concentration up to 100.0 pM with a detection limit of 0.721 fM. The method does not require complex labeling steps, and has a rapid response. It was successfully used to detect miRNA-21 directly in serum samples from heart failure patients without previous RNA extraction neither amplification process.