MicroRNAs in myocardial ischemia: identifying new targets and tools for treating heart disease. New frontiers for miR-medicine

Mitochondrial miRNA as epigenomic signatures: Visualizing aging-associated heart diseases through a new lens

Aging bears many hard knocks, but heart disorders earn a particular allusion, being the most widespread. Cardiovascular diseases (CVDs) are becoming the biggest concern to mankind due to sundry health conditions directly or indirectly related to heart-linked abnormalities. Scientists know that mitochondria play a critical role in the pathophysiology of cardiac diseases. Both environment and genetics play an essential role in modulating and controlling mitochondrial functions. Even a minor abnormality may prove detrimental to heart function. Advanced age combined with an unhealthy lifestyle can cause most cardiomyocytes to be replaced by fibrotic tissue which upsets the conducting system and leads to arrhythmias. An aging heart encounters far more heart-associated comorbidities than a young heart. Many state-of-the-art technologies and procedures are already being used to prevent and treat heart attacks worldwide. However, it remains a mystery when this heart bomb would explode because it lacks an alarm. This calls for a novel and effective strategy for timely diagnosis and a sure-fire treatment. This review article provides a comprehensive overture of prospective potentials of mitochondrial miRNAs that predict complicated and interconnected pathways concerning heart ailments and signature compilations of relevant miRNAs as biomarkers to plot the role of miRNAs in epigenomics. This article suggests that analysis of DNA methylation patterns in age-associated heart diseases may determine age-impelled biomarkers of heart disease.

Monocyte subpopulation profiling indicates CDK6-derived cell differentiation and identifies subpopulation-specific miRNA expression sets in acute and stable coronary artery disease

Coronary artery disease (CAD) is a long-lasting inflammatory disease characterized by monocyte migration into the vessel wall leading to clinical events like myocardial infarction (MI). However, the role of monocyte subsets, especially their miRNA-driven differentiation in this scenario is still in its infancy. Here, we characterized monocyte subsets in controls and disease phenotypes of CAD and MI patients using flow cytometry and miRNA and mRNA expression profiling using RNA sequencing. We observed major differences in the miRNA profiles between the classical (CD14⁺⁺CD16⁻) and nonclassical (CD14⁺CD16⁺⁺) monocyte subsets irrespective of the disease phenotype suggesting the Cyclin-dependent Kinase 6 (CDK6) to be an important player in monocyte maturation. Between control and MI patients, we found a set of miRNAs to be differentially expressed in the nonclassical monocytes and targeting CCND2 (Cyclin D2) that is able to enhance myocardial repair. Interestingly, miRNAs as miR-125b playing a role in vascular calcification were differentially expressed in the classical subset in patients suffering from CAD and not MI in comparison to control samples. In conclusion, our study describes specific peculiarities of monocyte subset miRNA expression in control and diseased samples and provides basis to further functional analysis and to identify new cardiovascular disease treatment targets.

Circulating microRNA-208 family as early diagnostic biomarkers for acute myocardial infarction: A meta-analysis

OBJECTIVE

Many recent studies have demonstrated that serum miRNA-208 (miR-208) could be a powerful biomarker in the early diagnosis of acute myocardial infarction (AMI). However, the result of previous studies was not accurate due to the small sample sizes and controversial issues. Therefore, this study was performed to investigate the relationship between the expression levels of miR-208 and AMI.

MATERIALS AND METHODS

According to the inclusion and exclusion criteria, a preliminary literature search was performed. The study was based on articles published in PubMed, Embase, Cochrane databases before September 30, 2019. Two staff members extracted data from the included articles for meta-analysis. These data were analyzed for sensitivity, specificity, diagnostic odds ratio, and summary receiver operator curve (SROC) analyses.

RESULTS

This study included 13 pieces of literature, which contains 1703 patients with AMI and 1589 controls. The main results of our meta-analysis were as follows: The pool sensitivity and specificity of miR-208 for diagnosing AMI was 83% and 97%. The area under the SROC curve (AUC) was 93%. Mir-208 had a highly effective diagnostic capacity to distinguish AMI from chest pain patients with an AUC of 93%.

CONCLUSIONS

The results showed that circulating miR-208 was a reliable biomarker both for diagnosting ST-elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction (NSTEMI). MiR-208 was sufficient to distinguish AMI patients with chest pain from healthy controls.

Identification of novel circulating microRNAs in advanced heart failure by next-generation sequencing

Aims

Risk stratification in patients with advanced chronic heart failure (HF) is an unmet need. Circulating microRNA (miRNA) levels have been proposed as diagnostic and prognostic biomarkers in several diseases including HF. The aims of the present study were to characterize HF‐specific miRNA expression profiles and to identify miRNAs with prognostic value in HF patients.

Methods and results

We performed a global miRNome analysis using next‐generation sequencing in the plasma of 30 advanced chronic HF patients and of matched healthy controls. A small subset of miRNAs was validated by real‐time PCR (P < 0.0008). Pearson's correlation analysis was computed between miRNA expression levels and common HF markers. Multivariate prediction models were exploited to evaluate miRNA profiles' prognostic role. Thirty‐two miRNAs were found to be dysregulated between the two groups. Six miRNAs (miR‐210‐3p, miR‐22‐5p, miR‐22‐3p, miR‐21‐3p, miR‐339‐3p, and miR‐125a‐5p) significantly correlated with HF biomarkers, among which N‐terminal prohormone of brain natriuretic peptide. Inside the cohort of advanced HF population, we identified three miRNAs (miR‐125a‐5p, miR‐10b‐5p, and miR‐9‐5p) altered in HF patients experiencing the primary endpoint of cardiac death, heart transplantation, or mechanical circulatory support implantation when compared with those without clinical events. The three miRNAs added substantial prognostic power to Barcelona Bio‐HF score, a multiparametric and validated risk stratification tool for HF (from area under the curve = 0.72 to area under the curve = 0.82).

Conclusions

This discovery study has characterized, for the first time, the advanced chronic HF‐specific miRNA expression pattern. We identified a few miRNAs able to improve the prognostic stratification of HF patients based on common clinical and laboratory values. Further studies are needed to validate our results in larger populations.

MicroRNA-1278 ameliorates the inflammation of cardiomyocytes during myocardial ischemia by targeting both IL-22 and CXCL14

AIMS

This study aimed to elucidate the role of microRNAs (miRNAs) during myocardial infarction (MI) development in vivo and in vitro.

MAIN METHODS

Differentially expressed miRNAs between heart tissue from the MI mouse model and the control mouse were identified via microarray. Quantitative PCR (qPCR) and western blotting (WB) were performed to examine the expression levels of miRNAs and proteins, respectively. EdU-staining and colony formation assay were performed to assess cell viability and growth. Annexin V- and PI-staining-based flow cytometry was used to assess cell apoptosis. An MI mouse model was also established to study the function of miR-1278 in vivo.

KEY FINDINGS

The levels of miR-1278 were reduced in the infarct regions of heart tissues of the MI mouse model and in H2O2-treated newborn murine ventricular cardiomyocytes (NMVCs) compared to those in the heart tissues of healthy mice and non-treated NMVCs. H2O2 treatment suppressed the proliferation of NMVCs, while miR-1278 upregulation improved it. Moreover, we found that miR-1278 inhibited the upregulation of IL-22 and CXCL14 expression in H2O2-treated NMVCs by directly binding with the 3'-UTRs of both IL-22 and CXCL14. Furthermore, restoration of IL-22 and CXCL14 in H2O2-treated NMVCs promoted miR-1278-induced inflammation and apoptosis. Administration of agomiR-1278 to the MI mouse model significantly improved cardiac activity.

SIGNIFICANCE

Collectively, our findings illustrate that the expression of miR-1278 is low in H2O2-treated NMVCs and post-MI cardiac tissues, and the overexpression of miR-1278 in these protects against cell death by modulating IL-22 and CXCL14 expression.

MicroRNA-369 attenuates hypoxia-induced cardiomyocyte apoptosis and inflammation via targeting TRPV3

Hypoxia-induced apoptosis and inflammation play an important role in cardiovascular diseases including myocardial infarction (MI). miR-369 has been suggested to be a key regulator of cardiac fibrosis. However, the role of miR-369 in regulating hypoxia-induced heart injury remains unknown. Our data indicated that miR-369 expression was significantly down-regulated and TRPV3 was significantly up-regulated in myocardial tissue after MI in rats and in hypoxic-treated neonatal rat cardiomyocytes (NRCMs). In addition, we observed that hypoxia significantly promoted apoptosis and the inflammatory response, accompanied by increased caspase-3 activity and the secretion of the cytokines interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α. miR-369 overexpression significantly suppressed cell apoptosis and inflammatory factor production triggered by hypoxia, whereas miR-369 inhibition had an opposite effect. Importantly, we identified TRPV3 as a direct target of miR-369-3p. TRPV3 inhibition with small interfering RNA (siRNA) significantly inhibited hypoxia-induced inflammation and apoptosis, which can reverse the injury effects of miR-369 inhibitors. Our findings indicated that miR-369 reduced hypoxia-induced apoptosis and inflammation by targeting TRPV3.

MiR-23b-3p promotes postmenopausal osteoporosis by targeting MRC2 and regulating the Wnt/β-catenin signaling pathway

Postmenopausal osteoporosis (PMOP) is one of the most common metabolic bone diseases in postmenopausal women. Increasing evidence has indicated that microRNAs (miRNAs) play vital regulatory roles during osteoporosis progression. This study aimed to investigate the potential function of miR-23b-3p in the osteogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs). PMOP was induced in mice by bilateral ovariectomy. X-ray absorptiometry was applied to detect BMD and BMC in PMOP mice. Luciferase reporter assay and RIP assay were utilized to investigate the relationship between miR-23b-3p and MRC2. We found the upregulation of miR-23b-3p in bone tissues of PMOP mice. Silencing of miR-23b-3p relieved PMOP in mice. Moreover, miR-23b-3p knockdown facilitated the osteogenic differentiation of hMSCs by increasing the expression of Runx2, OCN, Osterix and promoting ALP activity. Mechanistically, MRC2 is a downstream target gene of miR-23b-3p. MRC2 knockdown significantly rescued the promoting effect of lenti-miR-23b-3p inhibitor on osteogenic differentiation of hMSCs. Furthermore, miR-23b-3p targeted MRC2 to inhibit the Wnt/β-catenin pathway during the osteogenic differentiation of hMSCs. In summary, inhibition of miR-23b-3p alleviates PMOP by targeting MRC2 to inhibit the Wnt/β-catenin signaling, which may provide a novel molecular insight for osteoporosis therapy.

Diagnostic and prognostic value of circulating miRNA-499 and miRNA-22 in acute myocardial infarction

BACKGROUND

Currently, acute myocardial infarction (AMI) represents a serious cardiovascular disease with high morbidity and mortality. Therefore, this study aimed to systematically evaluate the roles of miRNA-499 and miRNA-22 as potential biomarkers for AMI.

METHODS

According to the inclusion and exclusion criteria, we measured circulating levels of miRNAs in 50 AMI patients and 50 non-MI populations. The expression levels of plasma miRNA-499 and miRNA-22 were analyzed by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). A statistical analysis of clinical data of AMI patients was conducted by 90-day follow-up.

RESULTS

Real-time PCR analysis showed that the relative expression level of miRNA-499 increased gradually among the three groups (P < .05). However, the expression of miRNA-22 showed a downward trend (P < .05). According to logistic analysis, the relative levels of miRNA-499 and miRNA-22 were important predictors of AMI. When the miRNA-499 and miRNA-22 levels were 0.377 and 0.946 separately, the diagnostic value of miRNA-499 and miRNA-22 for AMI was 86.00% and 86.00% for sensitivity, and 98.00% and 94.00% for specificity, respectively. In addition, compared to the baseline GRACE scoring system, the combination of miRNA-499, miRNA-22, and GRACE scores had a stronger discriminating power for MACE occurrence, with a sensitivity of 100.00% and a specificity of 79.40%.

CONCLUSIONS

The results showed that plasma miRNA-499 and miRNA-22 were more sensitive and specific for the diagnosis of AMI, suggesting that they can be used as potential biomarkers for clinical diagnosis of AMI.

Potential Clinical Implications of miR-1 and miR-21 in Heart Disease and Cardioprotection

The interest in non-coding RNAs, which started more than a decade ago, has still not weakened. A wealth of experimental and clinical studies has suggested the potential of non-coding RNAs, especially the short-sized microRNAs (miRs), to be used as the new generation of therapeutic targets and biomarkers of cardiovascular disease, an ever-growing public health issue in the modern world. Among the hundreds of miRs characterized so far, microRNA-1 (miR-1) and microRNA-21 (miR-21) have received some attention and have been associated with cardiac injury and cardioprotection. In this review article, we summarize the current knowledge of the function of these two miRs in the heart, their association with cardiac injury, and their potential cardioprotective roles and biomarker value. While this field has already been extensively studied, much remains to be done before research findings can be translated into clinical application for patient’s benefit.

Insight into long noncoding RNA-miRNA-mRNA axes in myocardial ischemia-reperfusion injury: the implications for mechanism and therapy

Emerging evidence has demonstrated that regulatory noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs) and miRNAs, play crucial roles in the initiation and progress of myocardial ischemia-reperfusion injury (MIRI), which is associated with autophagy, apoptosis and necrosis of cardiomyocytes, as well as oxidative stress, inflammation and mitochondrial dysfunction. LncRNAs serve as a precursor or host of miRNAs and directly/indirectly affecting miRNAs via competitive binding or sponge effects. Simultaneously, miRNAs post-transcriptionally regulate the expression of genes by targeting various mRNA sequences due to their imperfect pairing with mRNAs. This review summarizes the potential regulatory role of lncRNA-miRNA-mRNA axes in MIRI and related molecular mechanisms of cardiac disorders, also provides insight into the potential therapies for MIRI-induced diseases.

Core-Shell Polymer-Based Nanoparticles Deliver miR-155-5p to Endothelial Cells

Heart failure occurs in over 30% of the worldwide population and most commonly originates from cardiovascular diseases such as myocardial infarction. microRNAs (miRNAs) target and silence specific mRNAs, thereby regulating gene expression. Because the endogenous miR-155-5p has been ascribed to vasculoprotection, loading it onto positively charged, core-shell poly(isobutylcyanoacrylate) (PIBCA)-polysaccharide nanoparticles (NPs) was attempted. NPs showed a decrease (p < 0.0001) in surface electrical charge (ζ potential), with negligible changes in size or shape when loaded with the anionic miR-155-5p. Presence of miR-155-5p in loaded NPs was further quantified. Cytocompatibility up to 100 μg/mL of NPs for 2 days with human coronary artery endothelial cells (hCAECs) was documented. NPs were able to enter hCAECs and were localized in the endoplasmic reticulum (ER). Expression of miR-155-5p was increased within the cells by 75-fold after 4 hours of incubation (p < 0.05) and was still noticeable at day 2. Differences between loaded NP-cultured cells and free miRNA, at days 1 (p < 0.05) and 2 (p < 0.001) suggest the ability of prolonged load release in physiological conditions. Expression of miR-155-5p downstream target BACH1 was decreased in the cells by 4-fold after 1 day of incubation (p < 0.05). This study is a first proof of concept that miR-155-5p can be loaded onto NPs and remain intact and biologically active in endothelial cells (ECs). These nanosystems could potentially increase an endogenous cytoprotective response and decrease damage within infarcted hearts.

Abnormal expression of miR‑133a in patients with acute myocardial infarction following radical surgery for gastric cancer and the underlying mechanism

The present study aimed to investigate the expression of microRNA (miR)‑133a in patients with or without acute myocardial infarction (AMI) following radical surgery for gastric cancer, and to explore its underlying mechanisms. Blood samples were collected from patients with or without AMI in order to detect the expression levels of miR‑133a and endothelial injury markers. In addition, an AMI rat model was established. Reverse transcription‑quantitative polymerase chain reaction was used to detect the mRNA expression levels of miR‑133a and B‑cell lymphoma 2‑like 1 (Bcl2l1). In addition, an ELISA assay was used for endothelial injury marker analysis. To investigate the effects of miR‑133a on human umbilical vein endothelial cells (HUVECs), a miR‑133a inhibitor was used. Cell proliferation and apoptosis were subsequently detected using an MTT assay and flow cytometry. Western blot analysis was also conducted to detect Bcl2l1 protein expression. The results suggested that patients with AMI exhibited significantly increased expression of endothelial injury markers (von Willebrand factor, heart‑type fatty acid‑binding protein and cardiac troponin I) and miR‑133a in blood samples compared with patients without AMI. In addition, treatment with a miR‑133a mimic was able to upregulate the expression of endothelial injury markers in an AMI rat model, whereas treatment with a miR‑133a inhibitor had the opposite effect. Furthermore, cellular experiments indicated that a miR‑133a inhibitor could promote HUVEC proliferation and reduce cell apoptosis. The present results also confirmed that miR‑133a directly targets Bcl2l1 and negatively regulates Bcl2l1 expression. In conclusion, the results of the present study suggested that miR‑133a was involved in the endothelial injury process after AMI by targeting Bcl2l1.

MicroRNA-1 and Circulating Microvesicles Mediate the Protective Effects of Dantonic in Acute Myocardial Infarction Rat Models

Aim: To investigate the protective effect of dantonic in ischemic myocardial damage by evaluating the expression of circulating microvesicles (MVs) and microRNA-1 (miR-1) in two animal models.

Methods: Two animal models of myocardial ischemia were established that were isoproterenol-induced myocardial ischemia (ISO-AMI) rat model and the acute myocardial infarction rat model induced by ligation of the left anterior descending coronary artery (LAD-AMI) of rat. To investigate the protective effect of dantonic, we observed the myocardial infarction size, creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) activities, cardiac troponin I (cTnI) level in serum, and the plasma levels of miR-1 and MVs.

Results: The results showed that pretreatment with dantonic significantly attenuated the LAD-AMI induced myocardial damage by decreasing the size of myocardial infarction, CK, LDH, AST activities, and cTnI level in serum. High dose dantonic treatment could significantly abrogate the increased plasma levels of miR-1 and MVs as compared to the LAD rat model. In addition, pretreatment with dantonic also showed a significant myocardial protective effect through reducing the expression levels of CK, LDH, and AST as compared to the ISO-AMI model. Whereas the cTnI level was no significant difference between model group and control group, suggesting that the model caused less myocardial damage. In the ISO-induced myocardial ischemia model, there is no significant difference between the model group with the control group of MVs and miR-1 levels. This may be that miR-1 is reported as a biomarker of acute myocardial infarction. The pathological changes of IOS-induced acute myocardial ischemia model are also different from those of acute myocardial infarction.

Conclusion: Dantonic showed the protective effect in these two ischemic myocardial injury rat models, whereas the circulating miR-1 and MVs levels were only ameliorated in the LAD rat model.

Nanotechnology based approaches for detection and delivery of microRNA in healthcare and crop protection

Nanobiotechnology has the potential to revolutionize diverse sectors including medicine, agriculture, food, textile and pharmaceuticals. Disease diagnostics, therapeutics and crop protection strategies are fast emerging using nanomaterials preferably nanobiomaterials. It has potential for development of novel nanobiomolecules which offer several advantages over conventional treatment methods. RNA nanoparticles with many unique features are promising candidates in disease treatment. The miRNAs are involved in many biochemical and developmental pathways and their regulation in plants and animals. These appear to be a powerful tool for controlling various pathological diseases in human, plants and animals, however there are challenges associated with miRNA based nanotechnology. Several advancements made in the field of miRNA therapeutics make it an attractive approach, but a lot more has to be explored in nanotechnology assisted miRNA therapy. The miRNA based technologies can be employed for detection and combating crop diseases as well. Despite these potential advantages, nanobiotechnology applications in the agricultural sector are still in its infancy and have not yet made its mark in comparison with healthcare sector. The review provides a platform to discuss nature, role and use of miRNAs in nanobiotechnology applications.

Association of MIR-499a expression and seed region variant (rs3746444) with cardiovascular disease in Egyptian patients

BACKGROUND

Circulating microRNAs could be powerful markers of acute myocardial infarction (MI) and its functional genetic variants could increase susceptibility to cardiovascular disease (CVD). The current study aimed to quantify the microRNA (miR)-499a levels in serum of MI patients compared to hypertensive and healthy subjects and to investigate the association of its A/G variant rs3746444 with CVD in a sample of an Egyptian population.

METHODS

Serum miR-499a relative expressions were measured in 110 acute MI patients, 76 hypertensive patients, and 121 healthy controls by Real-time quantitative polymerase chain reaction. MIR-499a genotyping was performed for an additional 107 coronary artery disease patients by Real-time allele discrimination assay.

RESULTS

Acute MI patients showed high relative expression of miR-499a (> 105-fold, p < .001), and it was nearly undetectable in healthy controls and hypertensive patients. It showed an area under the curve of 0.953, with a sensitivity of 97.2% and a specificity of 75.0%. ST-elevation MI (STEMI) patients had higher miR-499a serum levels than patients with Non-STEMI. There was a significant association of MIR-499a variant with acute MI but not with hypertension under all genetic models tested. As a new finding, in overall and stratified analysis, the miR-499a variant was not correlated with its expression profile.

CONCLUSIONS

Circulating miR-499a levels could be a useful biomarker, discriminating acute MI within 12 hours from healthy subjects. Its variant rs3746444 A/G is associated with increased susceptibility to acute MI and CAD in Egyptian population.

MicroRNA-98 negatively regulates myocardial infarction-induced apoptosis by down-regulating Fas and caspase-3

Acute myocardial infarction (MI) is the leading cause of sudden death worldwide. MicroRNAs (miRs) is a novel class of regulators of cardiovascular diseases such as MI. This study aimed to explore the role of miR-98 in MI and its underlying mechanisms. We found that miR-98 was downregulated both in infarcted and ischemic myocardium of MI mice as well as H₂O₂-treated neonatal rat ventricular myocytes (NRVCs). miR-98 overexpression remarkably increased cell viability and inhibited apoptosis of H₂O₂-treated NRVCs. Meanwhile, overexpression of miR-98 reversed H₂O₂-induced Bcl-2 downregulation and Bax elevation and significantly reduced JC-1 monomeric cells. Meanwhile, miR-98 overexpression attenuated the upregulation of Fas and caspase-3 in H₂O₂-treated cardiomyocytes at the mRNA and protein levels. Dual-luciferase reporter assay showed that miR-98 directly targeted to Fas 3'-UTR. Furthermore, MI mice injected with miR-98-agomir had a significant reduction of apoptotic cells, the serum LDH levels, myocardial caspase-3 activity, Fas and caspase-3 expression in heart tissues. Administration of miR-98-agomir also showed decreased infarct size and improved cardiac function. Collectively, miR-98 is downregulated in the MI heart and NRVCs in response to H₂O₂ stress, and miR-98 overexpression protects cardiomyocytes against apoptosis. Anti-apoptotic effects of miR-98 are associated with regulation of Fas/Caspase-3 apoptotic signal pathway.

Higher coronary artery calcification score is associated with adverse prognosis in patients with stable angina pectoris

BACKGROUND

Coronary artery calcification (CAC) indicates the presence of atherosclerotic lesions and serves as a marker of prognosis in patients with coronary artery disease (CAD). This study evaluated the value of the CAC score for determining the prognosis of patients with stable angina pectoris (SAP).

METHODS

A total of 106 consecutive patients with SAP were enrolled in this study from January 2011 to June 2014; from these patients, 640 multi-slice computer tomography (MSCT) samples were used to obtain CAC scores. The CAC scores were calculated according to the standard Agatston calcium scoring algorithm. All subjects were divided into a lower CAC score group (CAC score, ≤300) and a higher CAC score group (CAC score, >300). Major adverse cardiac events (MACE) were followed-up, and the non-event survival time was recorded. The relationships between the CAC score and both clinical characteristics and MACE were then analysed.

RESULTS

The CAC positively correlated with age and the creatinine (Cr) level. Compared with patients who received lower CAC scores, the rates of percutaneous coronary intervention (PCI), MACE and multi-vessel disease were significantly higher in patients who received higher CAC scores. The Cox regression analysis results showed that the CAC score [pre-standard deviation (SD)] was a risk factor for the no-event survival time [hazard ratio (HR), 3.06; 95% confidence interval (CI), 1.47-6.38; P<0.05 for all]. However, the Kaplan-Meier analysis suggested that the rates of MACE did not differ between patients who were treated with PCI plus medical therapy and those who were treated with optimal medical therapy alone in both the higher and lower CAC score groups.

CONCLUSIONS

The CAC scores (per-SD) and MACE strongly and positively correlated in patients with SAP, and PCI was not related to the clinical prognosis of patients with SAP in either group.

Whole blood sequencing reveals circulating microRNA associations with high-risk traits in non-ST-segment elevation acute coronary syndrome

BACKGROUND AND AIMS

Although circulating microRNA (miRNAs) have emerged as biomarkers predicting mortality in acute coronary syndrome (ACS), more data are needed to understand these mechanisms. Mapping miRNAs to high-risk traits may identify miRNAs involved in pathways conferring risk for poor outcome in ACS. We aim to investigate the relationship between circulating miRNAs and high-risk traits in non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

METHODS

Whole-genome miRNA sequencing was performed on RNA extracted from whole blood of 199 patients with NSTE-ACS. Generalized linear models were used to test associations of miRNAs and 13 high-risk clinical traits, including the Global Registry of Acute Coronary Events (GRACE) score, a widely validated risk score for mortality in NSTE-ACS.

RESULTS

There were 205 nominally significant miRNA-risk factor associations (p < 0.05) observed. Significant associations occurred most frequently with chronic heart failure (HF) (43 miRs), GRACE risk score (30 miRs), and renal function (32 miRs). In hierarchical cluster analysis, chronic HF and GRACE risk score clustered most tightly together, sharing 14 miRNAs with matching fold-change direction. Controlling for a false discovery rate of 5%, chronic HF was significantly associated with lower circulating levels of miR-3135b (p < 0.0006), miR-126-5p (p < 0.0001), miR-142-5p (p = 0.0004) and miR-144-5p (p = 0.0007), while increasing GRACE risk score inversely correlated with levels of miR-3135b (p < 0.0001) and positively correlated with levels of miR-28-3p (p = 0.0002).

CONCLUSIONS

Circulating miRs clustered around two powerful traits for mortality risk in NSTE-ACS. MiR-3135b, which was under-expressed in chronic HF and increasing GRACE risk score, and miR-28-3p, which has no known association with cardiovascular disease, warrant further investigation.

MicroRNAs in Cardiovascular Disease: Perspectives and Reality

Since the discovery of the first noncoding RNA decades ago, the transcriptomics evolution has made a great leap reaching to the detection and recognition of microRNAs (miRNAs) in the early 1990s. Thereafter, numerous miRNAs were reported in different species, with a great body of literature focusing on their role in human health and in pathophysiological processes. miRNAs play a significant role in the cardiovascular system, not only in physiology and normal development but also in disease processes and evolution. Further studies on miRNAs have highlighted their participation in several expressions of cardiovascular disease, such as atherosclerosis, acute and chronic syndromes of coronary artery disease, heart failure, and cardiac arrhythmias. To date, the challenge remains to understand the underlying mechanisms of miRNAs that drive their expression profile so as to use them as innovative diagnostic tools or therapeutic targets in cardiovascular disease.

Renal Sympathetic Denervation in Rats Ameliorates Cardiac Dysfunction and Fibrosis Post-Myocardial Infarction Involving MicroRNAs

Background

The role of renal sympathetic denervation (RSD) in ameliorating post-myocardial infarction (MI) left ventricular (LV) fibrosis via microRNA-dependent regulation of connective tissue growth factor (CTGF) remains unknown.

Material/Methods

MI and RSD were induced in Sprague–Dawley rats by ligating the left coronary artery and denervating the bilateral renal nerves, respectively. Norepinephrine, renin, angiotensin II and aldosterone in plasma, collagen, microRNA21, microRNA 101a, microRNA 133a and CTGF in heart tissue, as well as cardiac function were evaluated six weeks post-MI.

Results

In the RSD group, parameters of cardiac function were significantly improved as evidenced by increased LV ejection fraction (p<0.01), LV end-systolic diameter (p<0.01), end-diastolic diameter (p<0.05), LV systolic pressure (p<0.05), maximal rate of pressure rise and decline (dP/dt_max and dP/dt_min, p<0.05), and decreased LV end-diastolic pressure (p<0.05) when compared with MI rats. Further, reduced collagen deposition in peri-infarct myocardium was observed in RSD-treated rats along with higher microRNA101a and microRNA133a (p<0.05) and lower microRNA21 expression (p<0.01) than in MI rats. CTGF mRNA and protein levels were decreased in LV following RSD (p<0.01), accompanied by decreased expression of norepinephrine, renin, angiotensin II and aldosterone in plasma (p<0.05) compared with untreated MI rats.

Conclusions

The potential therapeutic effects of RSD on post-MI LV fibrosis may be partly mediated by inhibition of CTGF expression via upregulation of microRNA 101a and microRNA 133a and downregulation of microRNA21.

Inhibition of MiR-92a May Protect Endothelial Cells After Acute Myocardial Infarction in Rats: Role of KLF2/4

Background

This study was designed to investigate the effects of microRNA-92 (miR-92), Kruppel-like factor 2 (KLF2), and Kruppel-like factor 4 (KLF4) on endothelial injury after acute myocardial infarction (AMI).

Material/Methods

Blood samples were collected from 50 AMI patients for detection of cardiac troponin I (cTnI), heart-type fatty acid-binding protein (H-FABP), and von Willebrand factor (vWF). The Sprague-Dawley rat models of AMI (n=30) were established by ligating their left anterior descending coronary artery. The cardiac markers of AMI patients and rat models were analyzed with enzyme-linked immunosorbent assay and immunohistochemistry. Human umbilical vein endothelial cells were processed into 5 groups: control, negative control, miR-92a inhibitors, miR-92a inhibitors + KLF2 small interfering RNA (siRNA), and miR-92a inhibitors + KLF4 siRNA. Cell proliferation and apoptosis were detected using MTT assay and flow cytometry. RT-PCR and Western blot were conducted to analyze KLF2 and KLF4 expressions.

Results

AMI patients exhibited significantly higher expression of both endothelial injury markers (e.g., cTnI, H-FABP, vWF) and miR-92a in blood samples, when compared with controls (P<0.05). Model rats also had similar expressional tendencies, along with lower KLF2 and KLF4 expressions (P<0.05). Further, it could be observed in cellular experiments that treatment of miR-92a mimics can further upregulate endothelial injury markers, and miR-92a and both KLF2 and KLF4 were downregulated by miR-92a mimics (all, P<0.05). Also, the luciferase activity assay confirmed the direct binding of miR-92a to 3′ UTR of KLF2/4.

Conclusions

MiR-92a was involved in the endothelial injury process after AMI and was able to suppress KLF2 and KLF4 expression.

miR-153 regulates apoptosis and autophagy of cardiomyocytes by targeting Mcl-1

MicroRNAs (miRs) are a class of important regulators, which are involved in the regulation of apoptosis. Oxidative stress‑induced apoptosis is the predominant factor accounting for cardiac ischemia‑reperfusion injury. miR‑153 has been previously shown to have an antitumor effect in cancer. However, whether miR‑153 is involved in oxidative stress‑induced apoptosis in the heart remains to be elucidated. To this end, the present study used reverse transcription‑quantitative polymerase chain reaction to detect miR-153 levels upon oxidative stress, and evaluated apoptosis, autophagy and expression of critical genes by western blotting. A luciferase assay was also used to confirm the potential target gene. In the present study, it was found that the expression of miR‑153 was significantly increased upon H2O2 stimulation, and the inhibition of endogenous miR‑153 decreased apoptosis. To further identify the mechanism underlying the pro‑apoptotic effect of miR‑153, the present study analyzed the 3'untranslated region of myeloid cell leukemia‑1 (Mcl‑1), and found that Mcl‑1 was potentially targeted by miR‑153. The forced expression of miR‑153 inhibited the expression of Mcl‑1 and luciferase activity, which was reversed by its antisense inhibitor. Furthermore, it was shown that the inhibition of miR‑153 induced autophagy during oxidative stress, and that its effects of autophagy induction and apoptosis inhibition were efficiently abrogated by Mcl‑1 small interfering RNA. In conclusion, the results of the present study elucidated a novel mechanism by which miR‑153 regulates the survival of cardimyocytes during oxidative stress through the modulation of apoptosis and autophagy. These effects may be mediated directly by targeting Mcl‑1. These finding revealed the potential clinical value of miR‑153 in the treatment of cardiovascular disease.

Discovery of Potential Therapeutic miRNA Targets in Cardiac Ischemia-Reperfusion Injury

BACKGROUND

A highly efficient approach to select microRNA (miRNA) targets is a key to develop a miRNA-based therapeutic approach to cardiac ischemia-reperfusion (I/R). To reverse the change induced by disease, I/R in this case, is the traditional strategy to develop therapeutic drugs. However, examples show that it will not always serve the purpose. In this study, we demonstrate an additional approach of selecting miRNA targets with therapeutic potential following cues from cardioprotection-induced changes rather than by reversing disease-induced changes in cardiac I/R.

METHODS

Isolated perfused rat hearts subjected to I/R were treated with 50 μmol/L sodium hydrosulfide (NaHS) or 10 nmol/L urocortin 2 (UCN2). Cardiac miRNA regulations were determined by miRNA array. Functional screening of selected miRNA mimics, assessed by WST (2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) activity and lactate dehydrogenase (LDH) release, was performed in H9c2 and neonatal rat ventricular myocytes (NRVMs) with hypoxia/reoxygenation. RNA-induced silencing complex (RISC)-loaded miRNAs caused by mimic transfection were quantified following argonaute-2 immunoprecipitation. Gene regulations of 1 selected miRNA were determined by quantitative polymerase chain reaction and Western blot.

RESULTS

Treatment with NaHS and UCN2 significantly improved cardiac function and reduced LDH release. The miRNA array indicated a panel of commonly up- and downregulated miRNAs. Among them, 10 upregulated miRNAs with antiapoptotic and antiautophagy potentials were selected for further screening. Mimics of miRNA-221, -150, and -206 were protective in both H9c2 and NRVM. RISC-loaded miRNAs were up by ∼20-fold above. To further prove the feasibility of this approach, miRNA-221 was studied. It reduced I/R-induced caspase 3/7 activity and LC3-II (microtubule-associated protein 1 light chain 3). Measuring genes predicted to regulate apoptosis and autophagy, miRNA-221 mimic decreased Ddit4, TP53inp1, and p27 at both messenger RNA (mRNA) and protein levels, and reduced mRNA of Bak1 and Puma and proteins of Bim and Bmf.

CONCLUSION

Mimicking miRNA changes caused by cardioprotective agents, combined with functional screening, enables investigators to efficiently identify novel miRNAs with therapeutic potential in cardiac I/R.

Epigenetic mechanisms in heart development and disease

Suboptimal intrauterine development has been linked to predisposition to cardiovascular disease in adulthood, a concept termed 'developmental origins of health and disease'. Although the exact mechanisms underlying this developmental programming are unknown, a growing body of evidence supports the involvement of epigenetic regulation. Epigenetic mechanisms such as DNA methylation, histone modifications and micro-RNA confer added levels of gene regulation without altering DNA sequences. These modifications are relatively stable signals, offering possible insight into the mechanisms underlying developmental origins of health and disease. This review will discuss the role of epigenetic mechanisms in heart development as well as aberrant epigenetic regulation contributing to cardiovascular disease. Additionally, we will address recent advances targeting epigenetic mechanisms as potential therapeutic approaches to cardiovascular disease.

MicroRNA-143/-145 in Cardiovascular Diseases

MicroRNAs (miRNAs) play an essential role in the onset and development of many cardiovascular diseases. Increasing evidence shows that miRNAs can be used as potential diagnostic biomarkers for cardiovascular diseases, and miRNA-based therapy may be a promising therapy for the treatment of cardiovascular diseases. The microRNA-143/-145 (miR-143/-145) cluster is essential for differentiation of vascular smooth muscle cells (VSMCs) and determines VSMC phenotypic switching. In this review, we summarize the recent progress in knowledge concerning the function of miR-143/-145 in the cardiovascular system and their role in cardiovascular diseases. We discuss the potential role of miR-143/-145 as valuable biomarkers for cardiovascular diseases and explore the potential strategy of targeting miR-143 and miR-145.

MicroRNA profiling of pericardial fluid samples from patients with heart failure

AIMS

Multicellular organisms maintain vital functions through intercellular communication. Release of extracellular vesicles that carry signals to even distant target organs is one way of accomplishing this communication. MicroRNAs can also be secreted from the cells in exosomes and act as paracrine signalling molecules. In addition, microRNAs have been implicated in the pathogenesis of a large number of diseases, including cardiovascular diseases, and are considered as promising candidate biomarkers due to their relative stability and easy quantification from clinical samples. Pericardial fluid contains hormones secreted by the heart and is known to reflect the cardiac function. In this study, we sought to investigate whether pericardial fluid contains microRNAs and if so, whether they could be used to distinguish between different cardiovascular pathologies and disease stages.

METHODS AND RESULTS

Pericardial fluid was collected from heart failure patients during open-heart surgery. MicroRNA profiles of altogether 51 patients were measured by quantitative real-time PCR (qPCR) using Exiqon human panels I and II. On the average, 256 microRNAs were detected per sample, and 70 microRNAs out of 742 profiled microRNAs were detected in every sample. The five most abundant microRNAs in pericardial fluid were miR-21-5p, miR-451a, miR-125b-5p, let-7b-5p and miR-16-5p. No specific signatures for cardiovascular pathologies or clinically assessed heart failure stages could be detected from the profiles and, overall, microRNA profiles of the samples were found to be very similar despite the heterogeneity in the study population.

CONCLUSION

Measured microRNA profiles did not separate the samples according to the clinical features of the patients. However, several previously identified heart failure marker microRNAs were detected. The pericardial fluid microRNA profile appeared to be a result of an active and selective secretory process indicating that microRNAs may act as paracrine signalling factors by mediating the local crosstalk between cardiac cells.