MicroRNA-101 Protects Against Cardiac Remodeling Following Myocardial Infarction via Downregulation of Runt-Related Transcription Factor 1

Investigating the expression level of miR-17-3p, miR-101-3p, miR-335-3p, and miR-296-3p in the peripheral blood of patients with acute myocardial infarction

The role of inflammation has been proven in acute myocardial infarction (AMI) pathogenesis. Due to the effect of NLRP3 gene expression in the inflammation process of MI, we aimed to explore the expression changes and diagnostic power of four inflammation-related miRNAs including miR-17-3p, miR-101-3p, miR-335-3p, miR-296-3p and their potential target, NLRP3, in ST-segment elevation myocardial infarction (STEMI), and non-STEMI (NSTEMI) patients as two major classes of AMI. The expression level of these genes were evaluated in 300 participants equally divided into three groups of STEMI, NSTEMI, and control using quantitative real-time PCR. The expression level of NLRP3 was upregulated in STEMI and NSTEMI patients compared to control subjects. Besides, the expression levels of miR-17-3p, miR-101-3p, and miR-296-3p were significantly downregulated in STEMI and NSTEMI patients compared to controls. The increased expression of NLRP3 had a very strong inverse correlation with miR-17-3p in patients with STEMI and with miR-101-3p in the STEMI and NSTEMI patients. ROC curve analysis showed that the expression level of miR-17-3p had the highest diagnostic power for discrimination between STEMI patients and controls. Remarkably, the combination of all markers resulted in a higher AUC. In summary, there is a significant association between the expression levels of miR-17-3p, miR-101-3p, miR-335-3p, miR-296-3p, and NLRP3 and the incidence of AMI. Although the miR-17-3p expression level has the highest diagnostic power to distinguish between STEMI patients and control subjects, the combination of these miRNAs and NLRP3 could serve as a novel potential diagnostic biomarker of STEMI.

Ribonucleicacid interference or small molecule inhibition of Runx1 in the border zone prevents cardiac contractile dysfunction following myocardial infarction

AIMS

Myocardial infarction (MI) is a major cause of death worldwide. Effective treatments are required to improve recovery of cardiac function following MI, with the aim of improving patient outcomes and preventing progression to heart failure. The perfused but hypocontractile region bordering an infarct is functionally distinct from the remote surviving myocardium and is a determinant of adverse remodelling and cardiac contractility. Expression of the transcription factor RUNX1 is increased in the border zone 1-day after MI, suggesting potential for targeted therapeutic intervention.

OBJECTIVE

This study sought to investigate whether an increase in RUNX1 in the border zone can be therapeutically targeted to preserve contractility following MI.

METHODS AND RESULTS

In this work we demonstrate that Runx1 drives reductions in cardiomyocyte contractility, calcium handling, mitochondrial density, and expression of genes important for oxidative phosphorylation. Both tamoxifen-inducible Runx1-deficient and essential co-factor common β subunit (Cbfβ)-deficient cardiomyocyte-specific mouse models demonstrated that antagonizing RUNX1 function preserves the expression of genes important for oxidative phosphorylation following MI. Antagonizing RUNX1 expression via short-hairpin RNA interference preserved contractile function following MI. Equivalent effects were obtained with a small molecule inhibitor (Ro5-3335) that reduces RUNX1 function by blocking its interaction with CBFβ.

CONCLUSIONS

Our results confirm the translational potential of RUNX1 as a novel therapeutic target in MI, with wider opportunities for use across a range of cardiac diseases where RUNX1 drives adverse cardiac remodelling.

MicroRNAs and cardiac fibrosis: A comprehensive update on mechanisms and consequences

Fibrosis is a pathological wound-healing mechanism that results by the overactivation of fibroblasts. Fibrosis can become obstructive and deleterious during regeneration of various body tissues including cardiac muscle. This ultimately results in the development of cardiac fibrosis, characterized by an excessive buildup of extracellular matrix proteins. Thus, it could lead to arrhythmias and heart failure which creates a leading public health burden worldwide. MiRNAs are small non-coding RNAs with great potential for diagnostic and therapeutic purposes. Mounting evidence indicates that miRNAs are involved in the deregulation of tissue homeostasis during myocardial fibrosis. For instance, miRNAs that are implicated in the regulation of TGF-beta signaling pathway have been reported to be significantly altered in myocardial fibrosis. Accordingly, in this comprehensive review, we discuss and highlight recent available data on the role of miRNAs during myocardial fibrosis, providing valuable insights into the miRNA modulation of cardiac fibrosis and miRNAs targets that can be used in the future therapeutic interventions to cardiac fibrosis.

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.

miRNAs Epigenetic Tuning of Wall Remodeling in the Early Phase after Myocardial Infarction: A Novel Epidrug Approach

Myocardial infarction (MI) is one of the leading causes of death in Western countries. An early diagnosis decreases subsequent severe complications such as wall remodeling or heart failure and improves treatments and interventions. Novel therapeutic targets have been recognized and, together with the development of direct and indirect epidrugs, the role of non-coding RNAs (ncRNAs) yields great expectancy. ncRNAs are a group of RNAs not translated into a product and, among them, microRNAs (miRNAs) are the most investigated subgroup since they are involved in several pathological processes related to MI and post-MI phases such as inflammation, apoptosis, angiogenesis, and fibrosis. These processes and pathways are finely tuned by miRNAs via complex mechanisms. We are at the beginning of the investigation and the main paths are still underexplored. In this review, we provide a comprehensive discussion of the recent findings on epigenetic changes involved in the first phases after MI as well as on the role of the several miRNAs. We focused on miRNAs function and on their relationship with key molecules and cells involved in healing processes after an ischemic accident, while also giving insight into the discrepancy between males and females in the prognosis of cardiovascular diseases.

Signs and signals limiting myocardial damage using PICSO: a scoping review decoding paradigm shifts toward a new encounter

Background

Inducing recovery in myocardial ischemia is limited to a timely reopening of infarct vessels and clearing the cardiac microcirculation, but additional molecular factors may impact recovery.

Objective

In this scoping review, we identify the paradigm shifts decoding the branching points of experimental and clinical evidence of pressure-controlled intermittent coronary sinus occlusion (PICSO), focusing on myocardial salvage and molecular implications on infarct healing and repair.

Design

The reporting of evidence was structured chronologically, describing the evolution of the concept from mainstream research to core findings dictating a paradigm change. All data reported in this scoping review are based on published data, but new evaluations are also included.

Results

Previous findings relate hemodynamic PICSO effects clearing reperfused microcirculation to myocardial salvage. The activation of venous endothelium opened a new avenue for understanding PICSO. A flow-sensitive signaling molecule, miR-145-5p, showed a five-fold increase in porcine myocardium subjected to PICSO.Verifying our theory of "embryonic recall," an upregulation of miR-19b and miR-101 significantly correlates to the time of pressure increase in cardiac veins during PICSO (r2 = 0.90, p < 0.05; r2 = 0.98, p < 0.03), suggesting a flow- and pressure-dependent secretion of signaling molecules into the coronary circulation. Furthermore, cardiomyocyte proliferation by miR-19b and the protective role of miR-101 against remodeling show another potential interaction of PICSO in myocardial healing.

Conclusion

Molecular signaling during PICSO may contribute to retroperfusion toward deprived myocardium and clearing the reperfused cardiac microcirculation. A burst of specific miRNA reiterating embryonic molecular pathways may play a role in targeting myocardial jeopardy and will be an essential therapeutic contribution in limiting infarcts in recovering patients.

IncRNA XIST Promotes Cardiac Fibrosis in Mice with Diabetic Nephropathy via Sponging miR-106a-5p to Target RUNX1

Diabetic nephropathy (DN) accompanied by cardiac fibrosis (CF) increases the mortality rate among people with diabetes. This study sought to explore the molecular mechanism of long non-coding RNA X inactive specific transcript (lncRNA XIST) in CF in DN mice. The animal model of DN was established by streptozocin (STZ). The levels of lncRNA XIST, microRNA (miR)-106a-5p, and RUNX family transcription factor 1 (RUNX1) were determined by quantitative real-time polymerase chain reaction (qRT-PCR), followed by biochemical analysis, hematoxylin & eosin and Masson staining, echocardiography, and quantification of collagen I, collagen III, α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) levels through qRT-PCR and Western blot assay. The subcellular localization of lncRNA XIST was analyzed by nuclear/cytoplasmic fractionation assay and the bindings of miR-106a-5p to lncRNA XIST and RUNX1 were confirmed by RNA immunoprecipitation and dual-luciferase assays. Functional rescue experiments were performed to validate the role of miR-106a-5p/RUNX1 in CF in DN mice. lncRNA XIST and RUNX1 were elevated while miR-106a-5p was decreased in STZ mice. lncRNA XIST inhibition reduced myocardial injury and collagen deposition, along with decreased levels of fasting blood glucose, serum creatinine, blood urea nitrogen, and urinary microalbumin, collagen I, collagen III, α-SMA, and TGF-β1. lncRNA XIST competitively bound to miR-106a-5p to promote RUNX1 transcription. miR-106a-5p downregulation or RUXN1 upregulation reversed the protective role of lncRNA XIST inhibition in STZ mice. lncRNA XIST competitively bound to miR-106a-5p to promote RUNX1 transcription, thereby aggravating renal dysfunction and CF in DN mice.

Natural emodin reduces myocardial ischemia/reperfusion injury by modulating the RUNX1/miR‑142‑3p/DRD2 pathway and attenuating inflammation

Acute myocardial infarction is one of the leading causes of death worldwide. Although timely reperfusion could attenuate myocardial ischemia injury and reduce mortality, it causes severe secondary injury to the myocardium known as myocardial ischemia/reperfusion injury (MIRI) with unmet clinical needs. Emodin has a protective effect on MIRI in rodents. However, the precise mechanism underlying its pharmacological effect remains poorly understood. Accordingly, the present study used mRNA and microRNA (miRNA) sequencing based on MIRI mouse models to determine the mechanism involved. Emodin was found to prevent MIRI and attenuate the inflammation of myocardium in the MIRI model. In addition, by using an interdisciplinary approach, the present study uncovered that emodin suppressed the runt-related transcription factor 1 (RUNX1), which is a transcription factor of miR-142-3p, in either MIRI or the hypoxia/reoxygenation injury model. Furthermore, miR-142-3p can negatively regulate dopamine receptor D2 (DRD2), which acted as an anti-inflammatory factor to suppress NF-κB-dependent inflammation and prevent MIRI. These results were demonstrated by both cellular hypoxia/reoxygenation and mouse MIRI models. Overall, the present study provided an unrevealed molecular mechanism for emodin function. Emodin could inhibit NF-κB-triggered inflammation in MIRI by regulating the RUNX1/miR-142-3p/DRD2 pathway. Therefore, the RUNX1/miR-142-3p/DRD2 pathway presented a novel target for MIRI treatment, and the application of emodin in clinical practice may improve the treatment of MIRI.

β-Catenin promotes long-term survival and angiogenesis of peripheral blood mesenchymal stem cells via the Oct4 signaling pathway

Stem cell therapy has been extensively studied to improve heart function following myocardial infarction; however, its therapeutic potency is limited by low rates of engraftment, survival, and differentiation. Here, we aimed to determine the roles of the β-catenin/Oct4 signaling axis in the regulation of long-term survival and angiogenesis of peripheral blood mesenchymal stem cells (PBMSCs). These cells were obtained from rat abdominal aortic blood. We showed that β-catenin promotes the self-renewal, antiapoptotic effects, and long-term survival of PBMSCs by activating the Oct4 pathway through upregulation of the expression of the antiapoptotic factors Bcl2 and survivin and the proangiogenic cytokine bFGF and suppression of the levels of the proapoptotic factors Bax and cleaved caspase-3. β-Catenin overexpression increased Oct4 expression. β-Catenin knockdown suppressed Oct4 expression in PBMSCs. However, β-catenin levels were not affected by Oct4 overexpression or knockdown. Chromatin immunoprecipitation assays proved that β-catenin directly regulates Oct4 transcription in PBMSCs. In vivo, PBMSCs overexpressing β-catenin showed high survival in infarcted hearts and resulted in better myocardial repair. Further functional analysis identified Oct4 as the direct upstream regulator of Ang1, bFGF, HGF, VEGF, Bcl2, and survivin, which cooperatively drive antiapoptosis and angiogenesis of engrafted PBMSCs. These findings revealed the regulation of β-catenin in PBMSCs by the Oct4-mediated antiapoptotic/proangiogenic signaling axis and provide a breakthrough point for improving the long-term survival and therapeutic effects of PBMSCs.

Boosting expression of a specific gene has allowed researchers to generate stem cells with increased capacity for tissue repair after a heart attack. Several studies have shown that treatment with a population of circulating cells known as ‘peripheral blood mesenchymal stem cells’ (PBMSCs) can regenerate cardiac tissue. These cells generally have a short lifespan when used therapeutically, but researchers led by Shaoheng Zhang at Jinan University in Guangzhou China have increased long-term survival and performance by boosting expression of the gene encoding β-catenin, a protein that promotes cell survival and proliferation. PBMSCs expressing increased levels of β-catenin preserved heart function in a rat model of heart attack, stimulating blood vessel growth and improving animal survival. This study also reveals proteins regulated by β-catenin, which could potentially be exploited for finer control of PBMSC function.

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.

Targeting RUNX1 as a novel treatment modality for pulmonary arterial hypertension

AIMS

Pulmonary arterial hypertension (PAH) is a fatal disease without a cure. Previously, we found that transcription factor RUNX1-dependent haematopoietic transformation of endothelial progenitor cells may contribute to the pathogenesis of PAH. However, the therapeutic potential of RUNX1 inhibition to reverse established PAH remains unknown. In the current study, we aimed to determine whether RUNX1 inhibition was sufficient to reverse Sugen/hypoxia (SuHx)-induced pulmonary hypertension (PH) in rats. We also aimed to demonstrate possible mechanisms involved.

METHODS AND RESULTS

We administered a small molecule specific RUNX1 inhibitor Ro5-3335 before, during, and after the development of SuHx-PH in rats to investigate its therapeutic potential. We quantified lung macrophage recruitment and activation in vivo and in vitro in the presence or absence of the RUNX1 inhibitor. We generated conditional VE-cadherin-CreERT2; ZsGreen mice for labelling adult endothelium and lineage tracing in the SuHx-PH model. We also generated conditional Cdh5-CreERT2; Runx1(flox/flox) mice to delete Runx1 gene in adult endothelium and LysM-Cre; Runx1(flox/flox) mice to delete Runx1 gene in cells of myeloid lineage, and then subjected these mice to SuHx-PH induction. RUNX1 inhibition in vivo effectively prevented the development, blocked the progression, and reversed established SuHx-induced PH in rats. RUNX1 inhibition significantly dampened lung macrophage recruitment and activation. Furthermore, lineage tracing with the inducible VE-cadherin-CreERT2; ZsGreen mice demonstrated that a RUNX1-dependent endothelial to haematopoietic transformation occurred during the development of SuHx-PH. Finally, tissue-specific deletion of Runx1 gene either in adult endothelium or in cells of myeloid lineage prevented the mice from developing SuHx-PH, suggesting that RUNX1 is required for the development of PH.

CONCLUSION

By blocking RUNX1-dependent endothelial to haematopoietic transformation and pulmonary macrophage recruitment and activation, targeting RUNX1 may be as a novel treatment modality for pulmonary arterial hypertension.

Dihydrolycorine Attenuates Cardiac Fibrosis and Dysfunction by Downregulating Runx1 following Myocardial Infarction

In spite of early interventions to treat acute myocardial infarction (MI), the occurrence of adverse cardiac remodeling following heart failure due to acute MI remains a clinical challenge. Thus, there is an increasing demand for the development of novel therapeutic agents capable of inhibiting the development of pathological ventricular remodeling. RNA-seq data analysis of acute MI rat models from GEO revealed that Runx1 was the most differentially expressed MI-related gene. In this study, we demonstrated that increased Runx1 expression under pathological conditions results in decreased cardiac contractile function. We identified dihydrolycorine, an alkaloid lycorine, as a promising inhibitor of Runx1. Our results showed that treatment with this drug could prevent adverse cardiac remodeling, as indicated by the downregulation of fibrotic genes using western blotting (collagen I, TGFβ, and p-smad3), downregulation of the apoptosis gene Bax, upregulation of the apoptosis gene Bcl-2, and improved cardiac functions, such as LVEF, LVSF, LVESD, and LVEDD. Additionally, dihydrolycorine treatment could rescue cardiomyocyte hypertrophy as demonstrated by wheat germ agglutinin staining, increased expression levels of the punctuate gap junction protein connexin 43, and decreased α-SMA expression, resulting in cardiomyocyte fibrosis in immunofluorescence staining. Molecular docking, binding modeling, and pull-down assays were used to identify potential dihydrolycorine-binding sites in Runx1. When Ad-sh-Runx1 was transfected into hypoxia-cardiomyocytes or injected into the hearts of MI rats, the cardioprotective effects of dihydrolycorine were abolished, and the normal electrophysiological activity of cardiomyocytes was disrupted. Taken together, the results of the present study indicate that dihydrolycorine may inhibit adverse cardiac remodeling after MI through the reduction of Runx1, suggesting that dihydrolycorine-mediated-Runx1 regulation might represent a novel therapeutic approach for adverse cardiac remodeling after MI.

MiR-135a Protects against Myocardial Injury by Targeting TLR4

Emerging evidence highlights the importance of microRNAs (miRNAs) as functional regulators in cardiovascular disease. This study aimed to investigate the functional significance of miR-135a in the regulation of cardiac injury after isoprenaline (ISO) stimulation and the underlying mechanisms of its effects. Murine models with cardiac-specific overexpression of miR-135a were constructed with an adeno-associated virus expression system. The cardiac injury model was induced by ISO injection (60 mg/kg per day for 14 d). In vitro, we used H9c2 cells to establish a cell injury model by ISO stimulation (10 µM). The results indicated that miR-135a was increased during days 0-6 of ISO injection and was then downregulated during days 8-14 of ISO injection. The expression of miR-135a was consistent with the in vivo findings. Moreover, mice with cardiac overexpression of miR-135a exhibited reduced cardiac fibrosis, lactate dehydrogenase levels, Troponin I, inflammatory response and apoptosis. Overexpression of miR-135a also ameliorated cardiac dysfunction induced by ISO. MiR-135 overexpression in H9c2 cells increased cell viability and decreased cell apoptosis and inflammation in response to ISO. Conversely, miR-135 silencing in H9c2 cells decreased cell viability and increased cell apoptosis and inflammation in response to ISO. Mechanistically, we found that miR-135a negatively regulated toll-like receptor 4 (TLR4), which was confirmed by luciferase assay. Furthermore, the TLR4 inhibitor eritoran abolished the adverse effect of miR-135 silencing. Overall, miR-135a promotes ISO-induced cardiac injury by inhibiting the TLR4 pathway. MiR-135a may be a therapeutic agent for cardiac injury.

A Brief Review on the Biology and Effects of Cellular and Circulating microRNAs on Cardiac Remodeling after Infarction

Despite advances in diagnostic, prognostic, and treatment modalities, myocardial infarction (MI) remains a leading cause of morbidity and mortality. Impaired cellular signaling after an MI causes maladaptive changes resulting in cardiac remodeling. MicroRNAs (miRNAs/miR) along with other molecular components have been investigated for their involvement in cellular signaling in the pathogenesis of various cardiac conditions like MI. miRNAs are small non-coding RNAs that negatively regulate gene expression. They bind to complementary mRNAs and regulate the rate of protein synthesis by altering the stability of their targeted mRNAs. A single miRNA can modulate several cellular signaling pathways by targeting hundreds of mRNAs. This review focuses on the biogenesis and beneficial effects of cellular and circulating (exosomal) miRNAs on cardiac remodeling after an MI. Particularly, miR-1, -133, 135, and -29 that play an essential role in cardiac remodeling after an MI are described in detail. The limitations that will need to be addressed in the future for the further development of miRNA-based therapeutics for cardiovascular conditions will also be discussed.

MicroRNA‑101 inhibits renal tubular epithelial‑to‑mesenchymal transition by targeting TGF‑β1 type I receptor

MicroRNAs (miRNAs/miRs) are key regulators of renal interstitial fibrosis (RIF). The present study was designed to identify miRNAs associated with the development of RIF, and to explore the ability of these identified miRNAs to modulate the renal tubular epithelial‑to‑mesenchymal transition (EMT) process. To this end, miRNAs that were differentially expressed between normal and fibrotic kidneys in a rat model of mercury chloride (HgCl₂)‑induced RIF were detected via an array‑based approach. Bioinformatics analyses revealed that miR‑101 was the miRNA that was most significantly downregulated in the fibrotic renal tissue samples, and this was confirmed by RT‑qPCR, which also demonstrated that this miRNA was downregulated in transforming growth factor (TGF)‑β1‑treated human proximal tubular epithelial (HK‑2) cells. When miR‑101 was overexpressed, this was sufficient to reverse TGF‑β1‑induced EMT in HK‑2 cells, leading to the upregulation of the epithelial marker, E‑cadherin, and the downregulation of the mesenchymal marker, α‑smooth muscle actin. By contrast, the downregulation of miR‑101 using an inhibitor exerted the opposite effect. The overexpression of miR‑101 also suppressed the expression of the miR‑101 target gene, TGF‑β1 type I receptor (TβR‑I), and thereby impaired TGF‑β1/Smad3 signaling, while the opposite was observed upon miR‑101 inhibition. To further confirm the ability of miR‑101 to modulate EMT, the HK‑2 cells were treated with the TβR‑I inhibitor, SB‑431542, which significantly suppressed TGF‑β1‑induced EMT in these cells. Notably, miR‑101 inhibition exerted a less pronounced effect upon EMT‑related phenotypes in these TβR‑I inhibitor‑treated HK‑2 cells, supporting a model wherein miR‑101 inhibits TGF‑β1‑induced EMT by suppressing TβR‑I expression. On the whole, the present study demonstrates that miR‑101 is capable of inhibiting TGF‑β1‑induced tubular EMT by targeting TβR‑I, suggesting that it may be an important regulator of RIF.

Epigenetics-based therapeutics for myocardial fibrosis

Myocardial fibrosis (MF) is a reactive remodeling process in response to myocardial injury. It is mainly manifested by the proliferation of cardiac muscle fibroblasts and secreting extracellular matrix (ECM) proteins to replace damaged tissue. However, the excessive production and deposition of extracellular matrix, and the rising proportion of type I and type III collagen lead to pathological fibrotic remodeling, thereby facilitating the development of cardiac dysfunction and eventually causing heart failure with heightened mortality. Currently, the molecular mechanisms of MF are still not fully understood. With the development of epigenetics, it is found that epigenetics controls the transcription of pro-fibrotic genes in MF by DNA methylation, histone modification and noncoding RNAs. In this review, we summarize and discuss the research progress of the mechanisms underlying MF from the perspective of epigenetics, including the newest m6A modification and crosstalk between different epigenetics in MF. We also offer a succinct overview of promising molecules targeting epigenetic regulators, which may provide novel therapeutic strategies against MF.

The stress hyperglycaemia ratio is associated with left ventricular remodelling after first acute ST-segment elevation myocardial infarction

BACKGROUND

Left ventricular negative remodelling after ST-segment elevation myocardial infarction (STEMI) is considered as the major cause for the poor prognosis. But the predisposing factors and potential mechanisms of left ventricular negative remodelling after STEMI remain not fully understood. The present research mainly assessed the association between the stress hyperglycaemia ratio (SHR) and left ventricular negative remodelling.

METHODS

We recruited 127 first-time, anterior, and acute STEMI patients in the present study. All enrolled patients were divided into 2 subgroups equally according to the median value of SHR level (1.191). Echocardiography was conducted within 24 h after admission and 6 months post-STEMI to measure left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), and left ventricular end-systolic diameter (LVESD). Changes in echocardiography parameters (δLVEF, δLVEDD, δLVESD) were calculated as LVEF, LVEDD, and LVESD at 6 months after infarction minus baseline LVEF, LVEDD and LVESD, respectively.

RESULTS

In the present study, the mean SHR was 1.22 ± 0.25 and there was significant difference in SHR between the 2 subgroups (1.05 (0.95, 1.11) vs 1.39 (1.28, 1.50), p < 0.0001). The global LVEF at 6 months post-STEMI was significantly higher in the low SHR group than the high SHR group (59.37 ± 7.33 vs 54.03 ± 9.64, p  = 0.001). Additionally, the global LVEDD (49.84 ± 5.10 vs 51.81 ± 5.60, p  = 0.040) and LVESD (33.27 ± 5.03 vs 35.38 ± 6.05, p  = 0.035) at 6 months after STEMI were lower in the low SHR group. Most importantly, after adjusting through multivariable linear regression analysis, SHR remained associated with δLVEF (beta = -9.825, 95% CI -15.168 to -4.481, p  < 0.0001), δLVEDD (beta = 4.879, 95% CI 1.725 to 8.069, p  = 0.003), and δLVESD (beta = 5.079, 95% CI 1.421 to 8.738, p  = 0.007).

CONCLUSIONS

In the present research, we demonstrated for the first time that SHR is significantly correlated with left ventricular negative remodelling after STEMI.

Diagnostic utility of circulating plasma microRNA-101a in severity of coronary heart disease

BACKGROUND

For evaluating the severity of coronary heart disease (CHD), coronary arteriography may not be available everywhere due to technical limitations. MicroRNA-101a (miR-101a) associated with inflammation and cholesterol homeostasis. However, whether it related to presence and stratification of CHD is still unknown.

AIM

We aim to evaluate the value of miR-101a in stratifying CHD patients.

METHODS

We enrolled 200 CHD patients and 100 controls, and 200 CHD patients were divided into two groups of low and high SYNTAX score (SYNTAX score ≤ 22 versus SYNTAX score ≥ 33). Intergroup comparisons of miR-101a level were compared among the controls and two groups of low and high SYNTAX score. Correlation between miR-101a and blood lipid profiles was analyzed. The logistic regression analysis were conducted to evaluate the risk factors of CHD.

RESULTS

Relative level of miR-101a in the controls, SYNTAX score ≤ 22 and SYNTAX score ≥ 33 group were 4.61 (1.24-8.91), 3.28 (0.58-6.75) and 2.29 (1.04-3.62), respectively (p < 0.001). All lipid profiles significantly associated with miR-101a expression (all p < 0.001). The odds ratio (OR) of miR-101a in univariate analysis was 0.41 (95% CI, 0.33-0.52). After adjusting for the traditional risk factors, such as blood profiles and history of smoking, the odds ratio of miR-101a was 0.63 (95% CI, 0.47-0.43), which closely associated with CHD (p = 0.002).

CONCLUSIONS

Circulating miR-101a may be considered as a novel biomarker for evaluating the presence and severity of CHD.

Circulating MicroRNAs: Biogenesis and Clinical Significance in Acute Myocardial Infarction

Acute myocardial infarction (AMI) causes many deaths around the world. Early diagnosis can prevent the development of AMI and provide theoretical support for the subsequent treatment. miRNAs participate in the AMI pathological processes. We aim to determine the early diagnostic and the prognostic roles of circulating miRNAs in AMI in the existing studies and summarize all the data to provide a greater understanding of their utility for clinical application. We reviewed current knowledge focused on the AMI development and circulating miRNA formation. Meanwhile, we collected and analyzed the potential roles of circulating miRNAs in AMI diagnosis, prognosis and therapeutic strategies. Additionally, we elaborated on the challenges and clinical perspectives of the application of circulating miRNAs in AMI diagnosis. Circulating miRNAs are stable in the circulation and have earlier increases of circulating levels than diagnostic golden criteria. In addition, they are tissue and disease-specific. All these characteristics indicate that circulating miRNAs are promising biomarkers for the early diagnosis of AMI. Although there are several limitations to be resolved before clinical use, the application of circulating miRNAs shows great potential in the early diagnosis and the prognosis of AMI.

RUNX1: an emerging therapeutic target for cardiovascular disease

Runt-related transcription factor-1 (RUNX1), also known as acute myeloid leukaemia 1 protein (AML1), is a member of the core-binding factor family of transcription factors which modulate cell proliferation, differentiation, and survival in multiple systems. It is a master-regulator transcription factor, which has been implicated in diverse signalling pathways and cellular mechanisms during normal development and disease. RUNX1 is best characterized for its indispensable role for definitive haematopoiesis and its involvement in haematological malignancies. However, more recently RUNX1 has been identified as a key regulator of adverse cardiac remodelling following myocardial infarction. This review discusses the role RUNX1 plays in the heart and highlights its therapeutic potential as a target to limit the progression of adverse cardiac remodelling and heart failure.

MiR-379 relieves myocardial injury after acute myocardial infarction by regulating tumor necrosis factor-α-induced protein 8

BACKGROUND

Acute myocardial infarction (AMI) is the myocardial avascular necrosis syndrome caused by coronary atherosclerotic plaque rupture, thrombosis or coronary artery occlusion. Therefore, it is of great significance to find new targets for the treatment of myocardial infarction. The purpose of this study was to investigate the effect of microRNA-379 (miR-379) on AMI and its mechanism.

METHODS

MiR-379 mimic was used to transfect H9c2 cells and we determined the protective effect of miR-379 on H9c2 by detecting the level of apoptosis. TargetScan software was used to detect miR-379's downstream targets. We constructed siRNA to analyze the effect of miR-379's downstream targets on H9c2 cells. In addition, we used miR-379 agomir to inject the tail vein of AMI rats to verify the effect of miR-379 on rat cardiomyocytes.

RESULTS

TargetScan detected that miR-379 and Tumor necrosis factor-α-induced protein 8 (TNFAIP8) may have binding sites and the dual luciferase reporter assay found that miR-379 binds to TNFAIP8 and inhibits its activity. MiR-379 mimic was found to reduce the expression of caspase3 and caspase9 in H9c2 cells and thereby reduce H2O2-induced cell damage. Inhibition of TNFAIP8 also significantly reduced apoptosis level and inhibited the NF-κB signaling pathway in H9c2 cells. Finally, miR-379 agomir was used to inject the tail vein of AMI rats and verified the protective effect of miR-379 in the heart in vivo.

CONCLUSIONS

MiR-379 has a binding site with TNFAIP8 and can inhibit its activity by binding to TNFAIP8 mRNA. SiRNA-TNFAIP8 can inhibit the NF-κB signaling pathway and protect myocardial cells from AMI-induced myocardial damage by reducing the apoptosis level of myocardial cells.

MicroRNA-101 Protects Against Cardiac Remodeling Following Myocardial Infarction via Downregulation of Runt-Related Transcription Factor 1

Background

Myocardial infarction (MI) generally leads to heart failure and sudden death. The hearts of people with MI undergo remodeling with the features of expanded myocardial infarct size and dilated left ventricle. Many microRNAs (miRs) have been revealed to be involved in the remodeling process; however, the participation of miR‐101 remains unknown. Therefore, this study aims to find out the regulatory mechanism of miR‐101 in MI‐induced cardiac remodeling.

Methods and Results

Microarray data analysis was conducted to screen differentially expressed genes in MI. The rat model of MI was established by left coronary artery ligation. In addition, the relationship between miR‐101 and runt‐related transcription factor 1 (RUNX1) was identified using dual luciferase reporter assay. After that, the rats injected with lentiviral vector expressing miR‐101 mimic, inhibitor, or small interfering RNA against RUNX1 were used to examine the effects of miR‐101 and RUNX1 on transforming growth factor β signaling pathway, cardiac function, infarct size, myocardial fibrosis, and cardiomyocyte apoptosis. RUNX1 was highly expressed, while miR‐101 was poorly expressed in MI. miR‐101 was identified to target RUNX1. Following that, it was found that overexpression of miR‐101 or silencing of RUNX1 improved the cardiac function and elevated left ventricular end‐diastolic and end‐systolic diameters. Also, miR‐101 elevation or RUNX1 depletion decreased infarct size, myocardial fibrosis, and cardiomyocyte apoptosis. Moreover, miR‐101 could negatively regulate RUNX1 to inactivate the transforming growth factor β1/Smad family member 2 signaling pathway.

Conclusions

Taken together, miR‐101 plays a protective role against cardiac remodeling following MI via inactivation of the RUNX1‐dependent transforming growth factor β1/Smad family member 2 signaling pathway, proposing miR‐101 and RUNX1 as potential therapeutic targets for MI.