Circulating miRNAs: novel biomarkers of acute coronary syndrome?

Predicting Diagnostic Gene Biomarkers Associated With Immune Checkpoints, N6-Methyladenosine, and Ferroptosis in Patients With Acute Myocardial Infarction

This study aimed to determine early diagnosis genes of acute myocardial infarction (AMI) and then validate their association with ferroptosis, immune checkpoints, and N6-methyladenosine (m6A), which may provide a potential method for the early diagnosis of AMI. Firstly, we downloaded microarray data from NCBI (GSE61144, GSE60993, and GSE42148) and identified differentially expressed genes (DEGs) in samples from healthy subjects and patients with AMI. Also, we performed systematic gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses and used STRING to predict protein interactions. Moreover, MCC and MCODE algorithms in the cytoHubba plug-in were used to screen nine key genes in the network. We then determined the diagnostic significance of the nine obtained DEGs by plotting receiver operating characteristic curves using a multiscale curvature classification algorithm. Meanwhile, we investigated the relationship between AMI and immune checkpoints, ferroptosis, and m6A. In addition, we further validated the key genes through the GSE66360 dataset and consequently obtained nine specific genes that can be used as early diagnosis biomarkers for AMI. Through screening, we identified 210 DEGs, including 53 downregulated and 157 upregulated genes. According to GO, KEGG, and key gene screening results, FPR1, CXCR1, ELANE, TLR2, S100A12, TLR4, CXCL8, FPR2 and CAMP could be used for early prediction of AMI. Finally, we found that AMI was associated with ferroptosis, immune checkpoints, and m6A and FPR1, CXCR1, ELANE, TLR2, S100A12, TLR4, CXCL8, FPR2 and CAMP are effective markers for the diagnosis of AMI, which can provide new prospects for future studies on the pathogenesis of AMI.

Development of Liposome-Based Immunoassay for the Detection of Cardiac Troponin I

Cardiovascular diseases (CVDs) are one of the foremost causes of mortality in intensive care units worldwide. The development of a rapid method to quantify cardiac troponin I (cTnI)—the gold-standard biomarker of myocardial infarction (MI) (or “heart attack”)—becomes crucial in the early diagnosis and treatment of myocardial infarction (MI). This study investigates the development of an efficient fluorescent “sandwich” immunoassay using liposome-based fluorescent signal amplification and thereby enables the sensing and quantification of serum-cTnI at a concentration relevant to clinical settings. The calcein-loaded liposomes were utilized as fluorescent nano vehicles, and these have exhibited appropriate stability and efficient fluorescent properties. The standardized assay was sensitive and selective towards cTnI in both physiological buffer solutions and spiked human serum samples. The novel assay presented noble analytical results with sound dynamic linearity over a wide concentration range of 0 to 320 ng/mL and a detection limit of 6.5 ng/mL for cTnI in the spiked human serum.

Nourin-Dependent miR-137 and miR-106b: Novel Early Inflammatory Diagnostic Biomarkers for Unstable Angina Patients

BACKGROUND

Currently, no blood biomarkers exist that can diagnose unstable angina (UA) patients. Nourin is an early inflammatory mediator rapidly released within 5 min by reversible ischemic myocardium, and if ischemia persists, it is also released by necrosis. Nourin is elevated in acute coronary syndrome (ACS) patients but not in symptomatic noncardiac and healthy subjects. Recently, circulating microRNAs (miRNAs) have been established as markers of disease, including cardiac injury and inflammation.

OBJECTIVES

To profile and validate the potential diagnostic value of Nourin-dependent miR-137 (marker of cell damage) and miR-106b-5p (marker of inflammation) as early biomarkers in suspected UA patients and to investigate the association of their target and regulating genes.

METHODS

Using Nourin amino acid sequence, an integrated bioinformatics analysis was conducted. Analysis indicated that Nourin is a direct target for miR-137 and miR-106b-5p in myocardial ischemic injury. Two linked molecular networks of lncRNA/miRNAs/mRNAs were also retrieved, including CTB89H12.4/miR-137/FTHL-17 and CTB89H12.4/miR-106b-5p/ANAPC11. Gene expression profiling was assessed in serum samples collected at presentation to an emergency department (ED) from: (1) UA patients (n = 30) (confirmed by invasive coronary angiography with stenosis greater than 50% and troponin level below the clinical decision limit); (2) patients with acute ST elevation myocardial infarction (STEMI) (n = 16) (confirmed by persistent ST-segment changes and elevated troponin level); and 3) healthy subjects (n = 16).

RESULTS

Gene expression profiles showed that miR-137 and miR-106b-5p were significantly upregulated by 1382-fold and 192-fold in UA compared to healthy, and by 2.5-fold and 4.6-fold in STEMI compared to UA, respectively. Healthy subjects showed minimal expression profile. Receiver operator characteristics (ROC) analysis revealed that the two miRNAs were sensitive and specific biomarkers for assessment of UA and STEMI patients. Additionally, Spearman's correlation analysis revealed a significant association of miRNAs with the associated mRNA targets and the regulating lncRNA.

CONCLUSIONS

Nourin-dependent gene expression of miR-137 and miR-106b-5p are novel blood-based biomarkers that can diagnose UA and STEMI patients at presentation and stratify severity of myocardial ischemia, with higher expression in STEMI compared to UA. Early diagnosis of suspected UA patients using the novel Nourin biomarkers is key for initiating guideline-based therapy that improves patients' health outcomes.

Do MicroRNAs Modulate Visceral Pain?

Visceral pain, a common characteristic of multiple diseases relative to viscera, impacts millions of people worldwide. Although hundreds of studies have explored mechanisms underlying visceral pain, it is still poorly managed. Over the past decade, strong evidence emerged suggesting that microRNAs (miRNAs) play a significant role in visceral nociception through altering neurotransmitters, receptors and other genes at the posttranscriptional level. Under pathological conditions, one kind of miRNA may have several target mRNAs and several kinds of miRNAs may act on one target, suggesting complex interactions and mechanisms between miRNAs and target genes lead to pathological states. In this review we report on recent progress in examining miRNAs responsible for visceral sensitization and provide miRNA-based therapeutic targets for the management of visceral pain.

Circulating miR-22-5p and miR-122-5p are promising novel biomarkers for diagnosis of acute myocardial infarction

BACKGROUND/AIMS

This study sought to evaluate the potential of circulating microRNAs (miRNAs) as novel indicators for acute myocardial infarction (AMI).

METHODS

Plasma samples were collected from each participant, and total RNA was extracted. Quantitative real-time polymerase chain reaction were used to investigate the expression of circulating miRNAs. We measured circulating levels of six individual miRNAs, which are known to be relevant to AMI, in the plasma samples from 66 AMI patients and 70 non-AMI healthy comparisons.

RESULTS

Five small RNAs were specifically expressed in AMI patients, plasma miR-122-5p levels is significantly elevated (p < 0.0001) in AMI patients, while plasma miR-22-5p ( p < 0.05) levels were significantly decreased. In addition, significant correlations between miR-22-5p and miR-122-5p ( R = 0.773), miR-122-5p and creatine kinase isoenzyme (CK-MB; R = 0.6296) were detected. Further, receiver operating characteristic (ROC) analysis indicated that miR-22-5p showed considerable diagnostic efficiency for predicting AMI (area under the curve [AUC] = 0.975). Combining miR-22-5p and miR-122-5p in a panel increased the sensitivity (98.6%) of distinguishing between patients with AMI and healthy comparisons.

CONCLUSION

Circulating miR-22-5p and miR-122-5p could be considered promising novel diagnostic biomarkers for AMI.

Epigenetic mechanisms in coronary artery disease: The current state and prospects

Coronary artery disease (CAD) is the leading cause of morbidity and mortality. CAD has both genetic and environmental causes. In the past two decades, the understanding of epigenetics has advanced swiftly and vigorously. It has been demonstrated that epigenetic modifications are associated with the onset and progression of CAD. This review aims to improve the understanding of the epigenetic mechanisms closely related to CAD and to provide a novel perspective on the onset and development of CAD. Epigenetic changes include DNA methylation, histone modification, microRNA and lncRNA, which are interrelated with critical genes and influence the expression of those genes. In addition, miRNA plays a diverse role in the pathological process of CAD. Numerous studies have found that some cardiac-specific miRNAs have potential as certain diagnostic biomarkers and treatment targets for CAD. In this review, the aberrant epigenetic mechanisms that contribute to CAD will be discussed. We will also provide novel insight into the epigenetic mechanisms that target CAD.

Elevated plasma miRNA-122, -140-3p, -720, -2861, and -3149 during early period of acute coronary syndrome are derived from peripheral blood mononuclear cells

OBJECTIVE

Our previous study has found that circulating microRNA (miRNA, or miR) -122, -140-3p, -720, -2861, and -3149 are significantly elevated during early stage of acute coronary syndrome (ACS). This study was conducted to determine the origin of these elevated plasma miRNAs in ACS.

METHODS

qRT-PCR was performed to detect the expression profiles of these 5 miRNAs in liver, spleen, lung, kidney, brain, skeletal muscles, and heart. To determine their origins, these miRNAs were detected in myocardium of acute myocardial infarction (AMI), and as well in platelets and peripheral blood mononuclear cells (PBMCs, including monocytes, circulating endothelial cells (CECs) and lymphocytes) of the AMI pigs and ACS patients.

RESULTS

MiR-122 was specifically expressed in liver, and miR-140-3p, -720, -2861, and -3149 were highly expressed in heart. Compared with the sham pigs, miR-122 was highly expressed in the border zone of the ischemic myocardium in the AMI pigs without ventricular fibrillation (P < 0.01), miR-122 and -720 were decreased in platelets of the AMI pigs, and miR-122, -140-3p, -720, -2861, and -3149 were increased in PBMCs of the AMI pigs (all P < 0.05). Compared with the non-ACS patients, platelets miR-720 was decreased and PBMCs miR-122, -140-3p, -720, -2861, and -3149 were increased in the ACS patients (all P < 0.01). Furthermore, PBMCs miR-122, -720, and -3149 were increased in the AMI patients compared with the unstable angina (UA) patients (all P < 0.05). Further origin identification revealed that the expression levels of miR-122 in CECs and lymphocytes, miR-140-3p and -2861 in monocytes and CECs, miR-720 in monocytes, and miR-3149 in CECs were greatly up-regulated in the ACS patients compared with the non-ACS patients, and were higher as well in the AMI patients than that in the UA patients except for the miR-122 in CECs (all P < 0.05).

CONCLUSION

The elevated plasma miR-122, -140-3p, -720, -2861, and -3149 in the ACS patients were mainly originated from CECs and monocytes.

Circulating MicroRNA-145 is Associated with Acute Myocardial Infarction and Heart Failure

Background:

Recent studies show that microRNA-145 (miRNA-145) might be an attractive tumor biomarker of considerable prognostic value, but little is known about their relationship with acute myocardial infarction (AMI). This study investigated the correlation between the level of miR-145 and AMI.

Methods:

One-hundred patients were divided into three groups: no coronary artery disease (CAD) group, non-ST segment elevation myocardial infarction group, and ST segment elevation myocardial infarction group. The plasma levels of miR-145 were quantified using real-time quantitative polymerase chain reaction. Logarithmic transformation of miRNA-145 levels (Ln_miRNA-145) was used for statistical analysis due to the skewed data distribution.

Results:

Plasma levels of miR-145 were significantly lower in patients with AMI compared to patients in the non-CAD group (−6.38 ± 0.11 vs. −4.47 ± 0.17, P < 0.0001). Compared to those without heart failure, the levels of miR-145 were significantly lower in patients with heart failure (−6.91 ± 0.20 vs. −5.35 ± 0.13, P < 0.0001). We also found that the lower plasma levels of miRNA-145 significantly correlated with increased serum levels of B-type natriuretic peptide (Spearman ρ= −0.60, P < 0.0001), troponin T (Spearman ρ= −0.62, P < 0.0001), and decreased ejection fraction (Spearman ρ= 0.65, P < 0.0001). In a multivariable linear regression analysis, AMI and heart failure were independently associated with lower Ln_miRNA-145 (estimate −0.99, standard error [SE] 0.28; P = 0.001 and estimate −0.62, SE 0.21; P = 0.004).

Conclusions:

Our results suggest that decreased plasma levels of miR-145 are associated with AMI. Circulating miR-145 may be useful in prognosticating cardiac function and the risk of developing heart failure.

Circulating Organ-Specific MicroRNAs Serve as Biomarkers in Organ-Specific Diseases: Implications for Organ Allo- and Xeno-Transplantation

Different cell types possess different miRNA expression profiles, and cell/tissue/organ-specific miRNAs (or profiles) indicate different diseases. Circulating miRNA is either actively secreted by living cells or passively released during cell death. Circulating cell/tissue/organ-specific miRNA may serve as a non-invasive biomarker for allo- or xeno-transplantation to monitor organ survival and immune rejection. In this review, we summarize the proof of concept that circulating organ-specific miRNAs serve as non-invasive biomarkers for a wide spectrum of clinical organ-specific manifestations such as liver-related disease, heart-related disease, kidney-related disease, and lung-related disease. Furthermore, we summarize how circulating organ-specific miRNAs may have advantages over conventional methods for monitoring immune rejection in organ transplantation. Finally, we discuss the implications and challenges of applying miRNA to monitor organ survival and immune rejection in allo- or xeno-transplantation.

The biology of circulating microRNAs in cardiovascular disease

BACKGROUND

Since their first description in mammalian cells, more than 2500 microRNA molecules have been predicted or verified within human cells. Recently, extracellular microRNAs have been described, protected from degradation by specialized packaging in extracellular vesicles or RNA-binding proteins.

MATERIALS AND METHODS

We will discuss recent data regarding circulating microRNAs, their potential role as novel biomarkers and intercellular communicators, as well as future challenges of studying and applying such novel biology, particularly in the cardiovascular system.

RESULTS

Circulating microRNAs have been proposed as attractive candidates as both diagnostic and prognostic biomarkers in various diseases, including a spectrum of cardiovascular conditions. Moreover, consistent with our evolving appreciation of the role of exosomes and microvesicles in intercellular communication, it has been proposed that delivery of active microRNAs to recipient tissues may serve as a primary mode of intercellular communication. Indeed, the transfer of functional microRNAs has been demonstrated in in vitro models and has been reported in a few in vivo contexts. In addition, therapeutic application of extracellular microRNAs has also been explored.

CONCLUSION

Over recent years, increasing attention has been paid to the role of circulating miRNAs in cardiovascular disease. As biomarkers and intercellular communicators, circulating miRNAs could play important roles in the prediction, diagnosis and tailored treatment of cardiovascular diseases in the near future.

Plasma Levels of microRNA-145 Are Associated with Severity of Coronary Artery Disease

Background and Objective

MicroRNAs (miRNAs) have been shown to be associated with various physiological and pathological conditions, including inflammation and cardiovascular disease, but little is known about their relationship with the presence of coronary artery disease (CAD) and disease severity.

Methods

A total of 195 consecutive subjects who underwent coronary angiography for chest pain evaluation were enrolled in this study. In CAD patients severity of coronary lesions was assessed by the number of diseased vessels and the Synergy between PCI with Taxus and Cardiac surgery score (SYNTAX score). Plasma levels of miRNA-145 were quantified by real-time quantitative polymerase chain reaction test, and logarithmic transformation of miRNA-145 levels (Ln_miRNA-145) was used for analyses due to its skewed distribution.

Results

Of the 195 total subjects 167 patients were diagnosed as having CAD. Ln_miRNA-145 was significantly lower in CAD patients compared with the non-CAD group (-6.11±0.92 vs. -5.06±1.25; p <0.001). In multivariable linear regression analyses CAD was significantly associated with lower Ln_miRNA-145 (Estimate, -0.50; standard error (SE), 0.11; p <0.0001). Furthermore, among CAD patients, three-vessel disease, higher SYNTAX scores and STEMI were significantly associated with lower Ln_miRNA-145 ([Estimate, -0.40; SE, 0.07; p <0.0001]; [Estimate, -0.02, SE, 0.10; p = 0.005] and [Estimate, -0.35, SE, 0.10; p <0.001] respectively).

Conclusions

Lower plasma levels of miRNA-145 were significantly associated with the presence as well as severity of CAD. As a potential biomarker for CAD, plasma miRNA-145 may be useful in predicting CAD and its severity in patients presenting with chest pain.

Plasma miR-122 and miR-3149 Potentially Novel Biomarkers for Acute Coronary Syndrome

OBJECTIVE

We evaluated the potentiality of plasma microRNAs (miRNAs, or miRs) that were considered as novel biomarkers for acute coronary syndrome (ACS), including acute myocardial infarction (AMI) and unstable angina (UA).

METHODS AND RESULTS

We initially identified plasma miR-122, -140-3p, -144, -720, -1225-3p, -2861, and -3149 as candidate miRNAs associated with AMI (≥2 fold and P < 0.05) by comparing expression differences of miRNAs among AMI, non-coronary heart disease (non-CHD) and stable angina (SA) groups, using miRNA microarrays (n = 8 independent arrays in each group). Those seven plasma miRNAs were further examined with qRT-PCR analyses in two replications including 111 and 428 patients separately, and the results demonstrated that plasma miR-122, -140-3p, -720, -2861, and -3149 were elevated in the ACS group vs. the non-ACS (non-CHD + SA) group (P < 0.01). The area under the receiver operating characteristic curve (AUC) of the five miRNAs for ACS classification was 0.838, 0.818, 0.865, 0.852, and 0.670, respectively (all P < 0.001), while the values reached 0.843 and 0.925 when simultaneously with miR-122 and -3149 or with miR-122, -2861, and -3149 together (all P < 0.001). In plasma of pigs after coronary ligation, miR-122 was increased from 180 min to 240 min and miR-3149 was augmented from 30 min to 240 min compared with the sham pigs (all P < 0.05).

CONCLUSION

Plasma miR-122, -140-3p, -720, -2861, and -3149 were associated with and potentially novel biomarkers for ACS.

Role of exosomes in myocardial remodeling

Exosomes are nanovesicles released from cells through exocytosis and are known to be mediators of proximal as well as distant cell-to-cell signaling. They are surrounded by a classical bilayered membrane with an exceptionally high cholesterol/phospholipid ratio. Exosomes were first described in 1977, then named prostasomes, and in 1987 the name exosome was coined. Exosomes contain surface proteins, some of which can act as labels in order to find their target cells. Exosomes also contain messages in the form of proteins and nucleic acids (RNA and DNA) that are transferable to target cells. Little is known and written about cardiac exosomes, although Gupta and Knowlton described exosomes containing HSP60 in 2007. It is now known that exosomes from cardiomyocytes can transfect other cells and that the metabolic milieu of the parental cell decides the quality of exosomes released such that they induce differential gene expression in transfected cells. Future clinical use of exosomes in diagnosis, monitoring disease progress, and treatment is promising.

Rapid upregulation and clearance of distinct circulating microRNAs after prolonged aerobic exercise

Short nonprotein coding RNA molecules, known as microRNAs (miRNAs), are intracellular mediators of adaptive processes, including muscle hypertrophy, contractile force generation, and inflammation. During basal conditions and tissue injury, miRNAs are released into the bloodstream as "circulating" miRNAs (c-miRNAs). To date, the impact of extended-duration, submaximal aerobic exercise on plasma concentrations of c-miRNAs remains incompletely characterized. We hypothesized that specific c-miRNAs are differentially upregulated following prolonged aerobic exercise. To test this hypothesis, we measured concentrations of c-miRNAs enriched in muscle (miR-1, miR-133a, miR-499-5p), cardiac tissue (miR-208a), and the vascular endothelium (miR-126), as well as those important in inflammation (miR-146a) in healthy male marathon runners (N = 21) at rest, immediately after a marathon (42-km foot race), and 24 h after the race. In addition, we compared c-miRNA profiles to those of conventional protein biomarkers reflective of skeletal muscle damage, cardiac stress and necrosis, and systemic inflammation. Candidate c-miRNAs increased immediately after the marathon and declined to prerace levels or lower after 24 h of race completion. However, the magnitude of change for each c-miRNA differed, even when originating from the same tissue type. In contrast, traditional biomarkers increased after exercise but remained elevated 24 h postexercise. Thus c-miRNAs respond differentially to prolonged exercise, suggesting the existence of specific mechanisms of c-miRNA release and clearance not fully explained by generalized cellular injury. Furthermore, c-miRNA expression patterns differ in a temporal fashion from corollary conventional tissue-specific biomarkers, emphasizing the potential of c-miRNAs as unique, real-time markers of exercise-induced tissue adaptation.

Circulating microRNAs as mirrors of acute coronary syndromes: MiRacle or quagMire?

Acute coronary syndrome (ACS), a leading cause of morbidity and mortality worldwide, is among the most serious cardiovascular diseases. Exploring novel approaches, which can complement and improve current strategies for ACS, is continuous. MicroRNAs (miRNAs) are a novel class of small, short non-coding RNA that post-transcriptionally regulate genes. The tissue- or cell-specific distribution features of miRNAs and its merit of stably existing in serum and plasma make them attractive biomarkers for ACS. An early and accurate diagnosis is the pre-requisite to facilitate rapid decision making and treatment and therefore improve outcome in ACS patients. This review highlights and summarizes recent studies using circulating miRNAs as novel biomarkers for ACS including its role in diagnosis, prediction, prognosis and reaction to therapy. In addition, we also discuss the potential function of miRNAs as extracellular communicators in cell-to-cell communication. Large multicentre studies are highly needed to pave the road for using circulating miRNAs as biomarkers for ACS from the bench to the bedside. Considering the advantageous properties and the continuously increasing number of studies, circulating miRNAs definitely have the potential to be reasonable diagnostic tools once their infancy has passed.