Detection of circRNA Biomarker for Acute Myocardial Infarction Based on System Biological Analysis of RNA Expression

Collaborative CRISPR-Cas System-Enabled Detection of Circulating Circular RNA for Reliable Monitoring of Acute Myocardial Infarction

Acute myocardial infarction (AMI) is one of the major causes of death worldwide, posing significant global health challenges. Circular RNA (circRNA) has recently emerged as a potential diagnostic biomarker for AMI, providing valuable information for timely medical care. In this work, a new electrochemical method for circRNA detection by engineering a collaborative CRISPR-Cas system is developed. This system integrates the unique circRNA-targeting ability with cascade trans-cleavage activities of Cas effectors, using an isothermal primer exchange reaction as the bridge. Using cZNF292, a circulating circRNA biomarker for AMI is identified by this group; as a model, the collaborative CRISPR-Cas system-based method exhibits excellent accuracy and sensitivity with a low detection limit of 2.13 × 10-15 m. Moreover, the method demonstrates a good diagnostic performance for AMI when analyzing whole blood samples. Therefore, the method may provide new insight into the detection of circRNA biomarkers and is expected to have great potential in AMI diagnosis in the future.

Non-Coding Ribonucleic Acids as Diagnostic and Therapeutic Targets in Cardiac Fibrosis

PURPOSE OF REVIEW

Cardiac fibrosis is a crucial juncture following cardiac injury and a precursor for many clinical heart disease manifestations. Epigenetic modulators, particularly non-coding RNAs (ncRNAs), are gaining prominence as diagnostic and therapeutic tools.

RECENT FINDINGS

miRNAs are short linear RNA molecules involved in post-transcriptional regulation; lncRNAs and circRNAs are RNA sequences greater than 200 nucleotides that also play roles in regulating gene expression through a variety of mechanisms including miRNA sponging, direct interaction with mRNA, providing protein scaffolding, and encoding their own products. NcRNAs have the capacity to regulate one another and form sophisticated regulatory networks. The individual roles and disease relevance of miRNAs, lncRNAs, and circRNAs to cardiac fibrosis have been increasingly well described, though the complexity of their interrelationships, regulatory dynamics, and context-specific roles needs further elucidation. This review provides an overview of select ncRNAs relevant in cardiac fibrosis as a surrogate for many cardiac disease states with a focus on crosstalk and regulatory networks, variable actions among different disease states, and the clinical implications thereof. Further, the clinical feasibility of diagnostic and therapeutic applications as well as the strategies underway to advance ncRNA theranostics is explored.

Serum circRNA (Circ)_0051386 assists in the diagnosis of acute ST-segment elevation myocardial infarction and prediction of the occurrence of major adverse cardiovascular events after percutaneous coronary intervention

BACKGROUND

This study aimed to uncover the diagnostic value of circRNA (Circ)_0051386 in acute ST-segment elevation myocardial infarction (STEMI) and its predictive value for the occurrence of adverse major adverse cardiovascular events (MACEs).

METHODS

This study included 166 patients with STEMI and 83 health donors. The expression levels of serum Circ_0051386 in these participants were quantified using real-time quantitative polymerase chain reaction (RT-qPCR). Additionally, the incidence of MACEs during a 6-month follow-up period after percutaneous coronary intervention (PCI) was collected in the STEMI patient cohort.

RESULTS

Before and after propensity score matching (PSM), Circ_0051386 all had higher expression levels in the patients with STEMI than the normal subjects (all p < .001)and robust diagnosis values for the STEMI (AUC = 0.766, 0.779). Kaplan-Meier curves showed the high expression Circ_0051386 group had a higher occurrence rate of MACEs during a 6-month follow-up after PCI in patients with STEMI and this phenomenon was confirmed by internal validation (all p < .05). In addition, the multivariate COX regression showed gensini score (HR = 1.020, 95% CI = 1.002 - 1.038, p = .028) and Circ_0051386 (HR = 2.468, 95% CI =1.548-3.935, p < .001)were independent risk factors of the occurrence of MACEs in patients with STEMI after PCI. Pearson analysis presented that Circ_0051386 was positively correlated with gensini scores (r = 0.33), IL-1β (r = 0.55)and TNF-α(r = 0.41).

CONCLUSION

Our study indicated that Circ_0051386 is a biomarker of the diagnostic for STEMI and the predictor of the MACEs in STEMI patients after PCI. Its potential role in STEMI may be the regulation of inflammation in the vascular endothelial.

Circ_0020887 Silencing Combats Hypoxic-Induced Cardiomyocyte Injury in an MiR-370-3p/CYP1B1-Dependent Manner

Targeting circular RNA has been a novel approach to preventing and limiting acute myocardial infarction (AMI). Here, we planned to investigate the role and mechanism of circ_0020887 in AMI progression.Hypoxic injury in human cardiomyocytes (AC16) was measured using cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, and colorimetric assay kits. RNA and protein expressions were determined using real-time quantitative PCR and western blotting. Direct interplay between RNAs was determined using dual-luciferase reporter, RNA pull-down, and RIP assays.In the plasma and hypoxia-induced AC16 cells of patients with AMI, circ_0020887 and miR-370-3p were upregulated and downregulated, respectively, concomitant with the upregulation of cytochrome P450 1B1 (CYP1B1). Circ_0020887 interference could inhibit hypoxia-induced AC16 cell apoptosis, oxidative stress, and inflammatory response. Circ_0020887 could sponge miR-370-3p, and miR-370-3p could target CYP1B1. The inhibition effect of circ_0020887 knockdown on hypoxia-induced AC16 cell injury could be reversed by the miR-370-3p inhibitor. Besides, CYP1B1 overexpression also overturned the suppressive effect of miR-370-3p on hypoxia-induced AC16 cell apoptosis, oxidative stress, and inflammatory response.In conclusion, circ_0020887 regulated the miR-370-3p/CYP1B1 axis to regulate hypoxia-induced cardiomyocyte injury, confirming that circ_0020887 might promote cardiomyocyte injury.

Diagnostic value of circRNA in coronary heart disease: a meta-analysis

Aim: Studies have indicated that circRNAs have diagnostic value for coronary heart disease (CHD), but the efficacy varies greatly; therefore, a meta-analysis was conducted to assess the diagnostic value of circRNAs in CHD. Materials & methods: 16 studies with 3962 subjects (2239 cases and 1723 controls) were included by searching PubMed, Web of Science and MEDLINE. The pooled sensitivity and specificity, summary receiver operating characteristic and area under the curve, positive likelihood ratio and negative likelihood ratio were calculated. Results: The pooled area under the curve of circRNAs for the diagnosis of CHD was 0.80 (sensitivity and specificity were 0.77 and 0.68, respectively), and more indexes were calculated. Conclusion: circRNAs may be good biomarkers for diagnosing CHD.

CircHSPG2 knockdown attenuates hypoxia-induced apoptosis, inflammation, and oxidative stress in human AC16 cardiomyocytes by regulating the miR-1184/MAP3K2 axis

Circular RNAs (circRNAs) have been identified as vital regulators in cardiovascular diseases, including acute myocardial infarction (AMI). In this study, the function and mechanism of circRNA heparan sulfate proteoglycan 2 (circHSPG2) in hypoxia-induced injury in AC16 cardiomyocytes were investigated. AC16 cells were stimulated with hypoxia to establish an AMI cell model in vitro. Real-time quantitative PCR and western blot assays were performed to quantify the expression levels of circHSPG2, microRNA-1184 (miR-1184), and mitogen-activated protein kinase kinase kinase 2 (MAP3K2). Counting Kit-8 (CCK-8) assay was used to measure cell viability. Flow cytometry was performed to detect cell cycle and apoptosis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the expression of inflammatory factors. Dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays were used to analyze the relationship between miR-1184 and circHSPG2 or MAP3K2. In AMI serum, circHSPG2 and MAP3K2 mRNA were highly expressed and miR-1184 was down-regulated. Hypoxia treatment elevated HIF1α expression and repressed cell growth and glycolysis. Moreover, hypoxia promoted cell apoptosis, inflammation, and oxidative stress in AC16 cells. Hypoxia-induced circHSPG2 expression in AC16 cells. CircHSPG2 knockdown alleviated hypoxia-induced AC16 cell injury. CircHSPG2 directly targeted miR-1184, and miR-1184 targeted and suppressed MAP3K2. Inhibition of miR-1184 or overexpression of MAP3K2 abolished the alleviated effect of circHSPG2 knockdown on hypoxia-induced AC16 cell injury. Overexpression of miR-1184 relieved hypoxia-induced impairment in AC16 cells by MAP3K2. CircHSPG2 could regulate MAP3K2 expression through miR-1184. CircHSPG2 knockdown protected AC16 cells from hypoxia-induced injury by regulating the miR-1184/MAP3K2 cascade.

The Landscape of Circular RNAs in Cardiovascular Diseases

Cardiovascular disease (CVD) remains the leading cause of mortality globally. Circular RNAs (circRNAs) have attracted extensive attention for their roles in the physiological and pathological processes of various cardiovascular diseases (CVDs). In this review, we briefly describe the current understanding of circRNA biogenesis and functions and summarize recent significant findings regarding the roles of circRNAs in CVDs. These results provide a new theoretical basis for diagnosing and treating CVDs.

The circRNA-miRNA/RBP regulatory network in myocardial infarction

Myocardial infarction (MI) is a serious heart disease that causes high mortality rate worldwide. Noncoding RNAs are widely involved in the pathogenesis of MI. Circular RNAs (circRNAs) are recently validated to be crucial modulators of MI. CircRNAs are circularized RNAs with covalently closed loops, which make them stable under various conditions. CircRNAs can function by different mechanisms, such as serving as sponges of microRNAs (miRNAs) and RNA-binding proteins (RBPs), regulating mRNA transcription, and encoding peptides. Among these mechanisms, sponging miRNAs/RBPs is the main pathway. In this paper, we systematically review the current knowledge on the properties and action modes of circRNAs, elaborate on the roles of the circRNA-miRNA/RBP network in MI, and explore the value of circRNAs in MI diagnosis and clinical therapies. CircRNAs are widely involved in MI. CircRNAs have many advantages, such as stability, specificity, and wide distribution, which imply that circRNAs have a great potential to act as biomarkers for MI diagnosis and prognosis.

Comprehensive Analysis of circRNA-miRNA-mRNA Regulatory Network and Novel Potential Biomarkers in Acute Myocardial Infarction

Background

Circular RNA (circRNA) plays an important role in the regulation of gene expression and the occurrence of human diseases. However, studies on the role of circRNA in acute myocardial infarction (AMI) are limited. This study was performed to explore novel circRNA-related regulatory networks in AMI, aiming to better understand the molecular mechanism of circRNAs involvement in AMI and provide basis for further scientific research and clinical decision-making.

Methods

The AMI-related microarray datasets GSE160717 (circRNA), GSE31568 (miRNA), GSE61741 (miRNA), and GSE24519 (mRNA) were obtained from the Gene Expression Omnibus (GEO) database. After differential expression analysis, the regulatory relationships between these DERNAs were identified by online databases circBank, circInteractome, miRDB, miRWalk, Targetscan, and then two circRNA-miRNA-mRNA regulatory networks were constructed. Differentially expressed genes (DEGs) in this network were selected followed by enrichment analysis and protein–protein interaction (PPI) analysis. Hub genes were identified using Cytohubba plug-in of Cytoscape software. Hub genes and hub gene-related miRNAs were used for receiver operating characteristic curve (ROC) analysis to identify potential biomarkers. The relative expression levels of these biomarkers were further assessed by GSE31568 (miRNA) and GSE66360 (mRNA). Finally, on the basis of the above analysis, myocardial hypoxia model was constructed to verify the expression of Hub genes and related circRNAs.

Results

A total of 83 DEcircRNAs, 109 CoDEmiRNAs and 1204 DEGs were significantly differentially expressed in these datasets. The up-regulated circRNAs and down-regulated circRNAs were used to construct a circRNA-miRNA-mRNA regulatory network respectively. These circRNA-related DEGs were mainly enriched in the terms of “FOXO signaling pathway,” “T cell receptor signaling pathway,” “MAPK signaling pathway,” “Insulin resistance,” “cAMP signaling pathway,” and “mTOR signaling pathway.” The top 10 hub genes ATP2B2, KCNA1, GRIN2A, SCN2B, GPM6A, CACNA1E, HDAC2, SRSF1, ANK2, and HNRNPA2B1 were identified from the PPI network. Hub genes GPM6A, SRSF1, ANK2 and hub gene-related circRNAs hsa_circ_0023461, hsa_circ_0004561, hsa_circ_0001147, hsa_circ_0004771, hsa_circ_0061276, and hsa_circ_0045519 were identified as potential biomarkers in AMI.

Conclusion

In this study, the potential circRNAs associated with AMI were identified and two circRNA-miRNA-mRNA regulatory networks were constructed. This study explored the mechanism of circRNA involvement in AMI and provided new clues for the selection of new diagnostic markers and therapeutic targets for AMI.

Extracellular Circular RNAs Act as Novel First Messengers Mediating Cell Cross-Talk in Ischemic Cardiac Injury and Myocardial Remodeling

Myocardial infarction (MI) causes most of the mortality worldwide. Coronary obstruction-caused myocardial ischemic injury leads to permanent loss of the myocardium. Subsequent compensatory myocardial remodeling and heart failure would result in arrhythmia and even sudden death. The molecular mechanisms of these pathological processes remain to be thoroughly revealed. Circular RNAs (circRNAs) are special types of non-coding RNAs which can durably regulate gene expression and modulate cell fate. They had been reported to mediate ischemic myocardial injury and myocardial remodeling. circRNAs can be loaded into extracellular vesicles and released into extracellular space. More recently, it was uncovered that the extracellular circRNAs can regulate intercellular communications, similar to "first messengers." The cross-talk mediated by extracellular circRNAs had been demonstrated to play important roles in pathological processes. Here, we would like to review the modulation of extracellular circRNAs in ischemic myocardial injury and myocardial remodeling. We believe the extracellular circRNAs can bring new strategies of MI treatment.

Diagnostic value of circRNAs as effective biomarkers in human cardiovascular disease: an updated meta-analysis

Background: A growing body of literature has demonstrated that circular RNAs (circRNAs) are the potential biomarkers in human cardiovascular disease (CVD). Therefore, a meta-analysis based on current studies was accomplished to appraise the role of circRNAs in the diagnostic of CVD patients. Methods: Studies before October 30, 2021, were searched using PubMed, EMBASE, the Web of Science, and Cochrane Library. The diagnostic odds ratio (DOR) with a confidence interval (CI) of 95% was used to investigate the associations between circRNAs and CVDs. Results: A total of 27 eligible articles were selected, including 47 studies, with 6833 participants meeting the criteria standard constrain. The pooled overall sensitivity and specificity for circRNAs expression profile in differentiating CVD patients from controls (non-CVDs or healthy subjects) were 0.81 (95%CI 0.78-0.83) and 0.74 (95%CI 0.68-0.78), respectively; the overall positive likelihood ratio was 3.1 (95%CI 2.5-3.7); the negative likelihood ratio was 0.26 (95%CI 0.22-0.31); the overall diagnostic odds ratio corresponding to an area under the curve of 0.85 (95%CI 0.81-0.88) was 12 (95%CI 9-16). Subgroup analysis indicated that the serum rather than blood has higher diagnostic accuracy. Likewise, meta-regression analysis demonstrated that the specimen, detection method, sample size, and publication year were the main sources of heterogeneity. Sensitivity analysis and Deeks' funnel plot revealed that our results are relatively robust. Conclusions: Our evidence-based analysis results suggested that circRNAs provide higher diagnostic accuracy in the prediction of CVDs. Thus, circRNAs might be potential biomarkers in CVDs.