Aberrant expression of plasma microRNA-33a in an atherosclerosis-risk group

Diagnostic and prognostic significance of miR-451a in patients with atherosclerosis

OBJECTIVES

Atherosclerosis (AS) is a chronic inflammatory vascular disease. This study aimed to detect the expression level of miR-451a and investigate the diagnostic and prognostic values of miR-451a for AS patients.

METHODS

The relative expression of miR-451a was assessed by qRT-PCR. Comparison of groups was analyzed with the t-test and chi-squared test. Pearson analysis was used to validate the correlation of miR-451 with CRP and CIMT. The receiver operating characteristic (ROC) curves, K-M analysis, and Cox regression analysis were conducted to explore the roles of miR-451a in diagnosing AS patients and predicting outcomes of AS patients.

RESULTS

The expression of miR-451a was significantly decreased in the serum of AS patients. The results of Pearson analysis showed the expression of miR-451a was negatively correlated with CRP and CIMT. The data of ROC proposed miR-451a could differentiate AS patients from healthy individuals with high sensitivity and specificity. K-M analysis and Cox regression showed miR-451a might be an independent biomarker of suffering cardiovascular endpoint diseases in AS patients. The expression of miR-451a was obviously inhibited in AS patients with cardiovascular endpoint events.

CONCLUSION

Deregulation of miR-451a might be associated with the development of AS. MiR-451a might be used as a promising diagnostic and prognostic biomarker for clinical treatment of AS patients.

Expression of ABC transporters during syncytialization in preeclampsia

Preeclampsia complicates 2-8% of pregnancies and is associated with prematurity and intrauterine growth restriction. Cholesterol and sterol transport is a key function of the placenta and it is elicited through ATP binding cassette (ABC) transporters. ABCA1 expression changes during trophoblast cell fusion, a process required to form the placental syncytium that enables maternal-fetal nutrient transfer. ABCA1 expression is dysregulated in preeclamptic placentas. But whether ABC transporters expression during trophoblast fusion is disrupted in preeclampsia remains unknown. We investigated if cholesterol and sterol ABC transporters are altered in term and preterm preeclampsia placentas and during human cytotrophoblast syncytialization. Human placental biopsies were collected from healthy term (≥37 weeks; n = 11) and term preeclamptic (≥36 6/7 weeks; n = 8) and pre-term preeclamptic (28-35 weeks; n = 8) pregnancies. Both, protein and mRNA expression for ABCA1, ABCG1, ABCG5, and ABCG8 were evaluated. Primary cytotrophoblasts isolated from a subset of placentas were induced to syncytialize for 96 h and ABCA1, ABCG1 and ABCG8 mRNA expression evaluated at 0 h and 96 h. Protein and gene expression of ABC transporters were not altered in preeclamptic placentas. In the healthy Term group, ABCA1 expression was similar before and after syncytialization. After 96 h of syncytialization, mRNA expression of ABCA1 and ABCG1 increased significantly, while ABCG8 decreased significantly in term-preeclampsia, but not pre-term preeclampsia. While placental expression of ABCA1 and ABCG1 remained unaltered in term preeclampsia, the disruption in their dynamic expression pattern during cytotrophoblast syncytialization suggests that cholesterol transport may contribute to the pathophysiologic role of the placenta in preeclampsia.

Effect of Xuezhikang Therapy on Expression of Pulmonary Hypertension Related miR-638 in Patients With Low HDL-C Levels

Objective: Low plasma level of high-density lipoprotein cholesterol (HDL-C) associated with poor outcomes in several cardiovascular diseases, including pulmonary arterial hypertension (PAH). Regulation of miR-638 have been proved to be associated with PAH. The aim of this study was to evaluate the expression of miR-638 after Xuezhikang (XZK) therapy in patients with low HDL-C.

Methods: Plasma levels of miR-638 were quantified by real-time polymerase chain reactions in 20 patients with PAH and 30 healthy controls. A total of 40 subjects with low HDL-C were assigned to receive an XZK therapy for 6 months. The miR-638 expression profiles were detected in PAH patients, XZK-treated subjects and lovastatin treated pulmonary arterial smooth muscle cells (PA-SMCs).

Results: The relative expression level of miR-638 in the plasma was lower in the PAH patients than that in the controls (p < 0.001). An increase of 11.2% from baseline in the HDL-C level was found after XZK therapy (p < 0.001). The relative expression of miR-638 was increased after XZK treatment (p < 0.01). The changes of miR-638 were inversely associated with baseline HDL-C levels. A significantly reduction in miR-638 expression were found in PDGF-BB-treated hPA-SMCs compared to the control cells, and the pre-treatment of the cells with lovastatin significantly re-gain the expression levels in miR-638.

Conclusion: In patients with low HDL-C levels, XZK therapy raised the expression of miR-638, suggesting that the potential therapeutic effect of XZK in PAH patients with low serum HDL-C levels deserves further exploration.

Genomic Variants and Multilevel Regulation of ABCA1, ABCG1, and SCARB1 Expression in Atherogenesis

Atheroprotective properties of human plasma high-density lipoproteins (HDLs) are determined by their involvement in reverse cholesterol transport (RCT) from the macrophage to the liver. ABCA1, ABCG1, and SR-BI cholesterol transporters are involved in cholesterol efflux from macrophages to lipid-free ApoA-I and HDL as a first RCT step. Molecular determinants of RCT efficiency that may possess diagnostic and therapeutic meaning remain largely unknown. This review summarizes the progress in studying the genomic variants of ABCA1, ABCG1, and SCARB1, and the regulation of their function at transcriptional and post-transcriptional levels in atherosclerosis. Defects in the structure and function of ABCA1, ABCG1, and SR-BI are caused by changes in the gene sequence, such as single nucleotide polymorphism or various mutations. In the transcription initiation of transporter genes, in addition to transcription factors, long noncoding RNA (lncRNA), transcription activators, and repressors are also involved. Furthermore, transcription is substantially influenced by the methylation of gene promoter regions. Post-transcriptional regulation involves microRNAs and lncRNAs, including circular RNAs. The potential biomarkers and targets for atheroprotection, based on molecular mechanisms of expression regulation for three transporter genes, are also discussed in this review.

Diagnostic and Prognostic Significance of miR-675-3p in Patients With Atherosclerosis

In recent years, a rising number of studies have confirmed that microRNA (miRNA) plays a prominent role in the early diagnosis and prognostic value assessment of cardiovascular diseases. The current study was conducted to examine the expression of miR-675-3p in atherosclerosis (AS) patients and to evaluate its clinical diagnosis and prognostic value. 110 AS patients and 70 healthy controls were included in the study. Serum miR-675-3p levels were detected by quantitative real-time PCR (qRT-PCR). The clinical diagnostic significance of serum miR-675-3p in AS patients were investigated by the receiver operating characteristic (ROC) curve. The correlation between miRNA and carotid intima-media thickness (CIMT) was analyzed by the Spearman correlation coefficient. The prognostic significance of serum miR-675-3p was evaluated by the Kaplan-Meier method and Cox regression analysis. The patient’s serum miR-675-3p was significantly increased than the healthy individuals (P < 0.05). An increase of carotid intima-media thickness (CIMT) was positively correlated with the promotion of serum miR-675-3p levels. The area under the ROC curve (AUC) was 0.918, with high sensitivity and specificity. miR-675-3p is a key independent predictor of cardiovascular adverse events in AS patients (HR = 5.375, 95%CI = 1.590-18.170, P = 0.007), and patients with elevated miR-675-3p were more likely to have cardiovascular adverse events (log-rank P = 0.030). Increased miR-675-3p can be used as a potential marker for the diagnosis of AS, and was associated with the poor prognosis of AS.

miR-33a-5p Suppresses ox-LDL-Stimulated Calcification of Vascular Smooth Muscle Cells by Targeting METTL3

Oxidized low-density lipoprotein (ox-LDL) accumulation in the vascular wall plays a pivotal role in the development of atherosclerosis and vascular calcification. However, few studies focus on the regulatory roles of microRNAs in ox-LDL stimulated vascular calcification. The aim of the present study was to investigate how miR-33a-5p regulated vascular calcification stimulated by ox-LDL. In the present study, miR-33a-5p was downregulated during vascular smooth muscle cells (VSMCs) calcification and upon ox-LDL treatment. ox-LDL significantly stimulated VSMCs calcification, while miR-33a-5p overexpression by its mimics transfection inhibited alkaline phosphatase (ALP) activity, mineralization and marker genes associated with VSMCs calcification even in the presence of ox-LDL. Methyltransferase like 3 (METTL3) was the target gene of miR-33a-5p. METTL3 was upregulated during VSMCs calcification and upon ox-LDL treatment. When VSMCs were transfected with miR-33a-5p mimics, METTL3 was downregulated. METTL3 downregulation by siRNA method decreased VSMCs calcification even in the presence of ox-LDL. Taken together, these results suggest miR-33a-5p suppresses VSMCs calcification stimulated by ox-LDL via targeting METTL3, highlighting the critical role of miR-33a-5p/METTL3 in vascular calcification.

The effectiveness of plasma miR-33a-5p as a predictive biomarker for the efficacy of colorectal cancer chemotherapy

Several chemotherapeutic options are available for patients with metastatic colorectal cancer (mCRC), making it important to individualize treatment regimens. Individualization requires the clinical application of biomarkers for regimen selection, which is presently insufficient. miRNAs serve an important role in the control of biological processes in several types of cancer, acting as plasma biomarkers. The current study aimed to evaluate novel plasma microRNAs for predicting chemo-resistance in chemotherapy for patients with colorectal cancer (CRC) by employing a Toray 3D-Gene microRNA array-based approach, which compared plasma content before and during treatment. Specific miRNAs that acted as biomarkers of the fluoropyrimidine (FP) + oxaliplatin (OX) + bevacizumab (BEV) regime, a common first-line treatment for mCRC, were searched. The plasma samples of 110 patients with mCRC who had received the FP+OX+BEV regimen were subjected to microarray analyses using the 3D-Gene miRNA microarray platform, after which miRNAs levels were quantified via reverse transcription- quantitative PCR. Patients exhibiting complete response, partial response (PR) and reduced stable disease (SD) were defined as responders. Patients with extended SD and progression disease (PD) were defined as non-responders. Following microarray analysis, miR-33a-5p was selected as the candidate miRNA as it was upregulated in non-responder plasma samples. The expression of miR-33a-5p was upregulated in the non-responders (n=15) compared with the responders (n=95) (P=0.032). The high expression group demonstrated significantly poor progression-free survival (P<0.01). To evaluate whether miR-33a-5p can serve as a marker of chemo-resistance, miR-33a-5p expression levels were assessed at the following three time-points: Pre-point (before chemotherapy); PR-point (3-months after chemotherapy began); and PD-point (the time at which recurrence or progression was recorded). The results revealed that expression levels were significantly increased at the PD-point when compared with that at the pre-point (P=0.024). The current study determined that the miR-33a-5p expression level in the plasma may serve as a predictive marker of efficacy and as a biomarker of chemo-resistance.

Regulation of microRNA-33, SREBP and ABCA1 genes in a mouse model of high cholesterol

MicroRNAs are short non-coding RNAs that regulate gene expression. Several microRNAs, useful for coronary artery disease assessment, have previously been identified. MicroRNA-33 is located within SREBP introns and controls cholesterol homeostasis. In order to find the possibility of microRNA-33 as a potential biomarker in high cholesterol disease, we developed a mouse model for coronary heart disease by feeding mice with a high-fat diet. The expression differences of microRNA-33, SREBP and ABCA1 genes in the liver, muscle, and lipid tissues were compared between a high-cholesterol group and control group in mice. The results showed that ABCA1 was up-regulated by high cholesterol conditions in liver, muscle and lipid tissues. SREBP1C was up-regulated by high cholesterol conditions in the liver and lipid tissues and down-regulated by high cholesterol conditions in the muscle tissue. MicroRNA-33 and SREBP2 were down-regulated by high cholesterol conditions in the liver and muscle tissues and up-regulated by high cholesterol conditions in the lipid tissue. Our study suggests that antisense therapeutic targeting of microRNA-33 may be a potential biomarker for cardiovascular disease.

MicroRNA sequences modulating inflammation and lipid accumulation in macrophage “foam” cells: Implications for atherosclerosis

Accumulation of macrophage “foam” cells, laden with cholesterol and cholesteryl ester, within the intima of large arteries, is a hallmark of early “fatty streak” lesions which can progress to complex, multicellular atheromatous plaques, involving lipoproteins from the bloodstream and cells of the innate and adaptive immune response. Sterol accumulation triggers induction of genes encoding proteins mediating the atheroprotective cholesterol efflux pathway. Within the arterial intima, however, this mechanism is overwhelmed, leading to distinct changes in macrophage phenotype and inflammatory status. Over the last decade marked gains have been made in understanding of the epigenetic landscape which influence macrophage function, and in particular the importance of small non-coding micro-RNA (miRNA) sequences in this context. This review identifies some of the miRNA sequences which play a key role in regulating “foam” cell formation and atherogenesis, highlighting sequences involved in cholesterol accumulation, those influencing inflammation in sterol-loaded cells, and novel sequences and pathways which may offer new strategies to influence macrophage function within atherosclerotic lesions.

Dysregulations of MicroRNA and Gene Expression in Chronic Venous Disease

Chronic venous disease (CVD) is a vascular disease of lower limbs with high prevalence worldwide. Pathologic features include varicose veins, venous valves dysfunction and skin ulceration resulting from dysfunction of cell proliferation, apoptosis and angiogenesis. These processes are partly regulated by microRNA (miRNA)-dependent modulation of gene expression, pointing to miRNA as a potentially important target in diagnosis and therapy of CVD progression. The aim of the study was to analyze alterations of miRNA and gene expression in CVD, as well as to identify miRNA-mediated changes in gene expression and their potential link to CVD development. Using next generation sequencing, miRNA and gene expression profiles in peripheral blood mononuclear cells of subjects with CVD in relation to healthy controls were studied. Thirty-one miRNAs and 62 genes were recognized as potential biomarkers of CVD using DESeq2, Uninformative Variable Elimination by Partial Least Squares (UVE-PLS) and ROC (Receiver Operating Characteristics) methods. Regulatory interactions between potential biomarker miRNAs and genes were projected. Functional analysis of microRNA-regulated genes revealed terms closely related to cardiovascular diseases and risk factors. The study shed new light on miRNA-dependent regulatory mechanisms involved in the pathology of CVD. MicroRNAs and genes proposed as CVD biomarkers may be used to develop new diagnostic and therapeutic methods.

Epigenetic Biomarkers in Cardiovascular Diseases

Cardiovascular diseases are the number one cause of death worldwide and greatly impact quality of life and medical costs. Enormous effort has been made in research to obtain new tools for efficient and quick diagnosis and predicting the prognosis of these diseases. Discoveries of epigenetic mechanisms have related several pathologies, including cardiovascular diseases, to epigenetic dysregulation. This has implications on disease progression and is the basis for new preventive strategies. Advances in methodology and big data analysis have identified novel mechanisms and targets involved in numerous diseases, allowing more individualized epigenetic maps for personalized diagnosis and treatment. This paves the way for what is called pharmacoepigenetics, which predicts the drug response and develops a tailored therapy based on differences in the epigenetic basis of each patient. Similarly, epigenetic biomarkers have emerged as a promising instrument for the consistent diagnosis and prognosis of cardiovascular diseases. Their good accessibility and feasible methods of detection make them suitable for use in clinical practice. However, multicenter studies with a large sample population are required to determine with certainty which epigenetic biomarkers are reliable for clinical routine. Therefore, this review focuses on current discoveries regarding epigenetic biomarkers and its controversy aiming to improve the diagnosis, prognosis, and therapy in cardiovascular patients.

Epigenetics of chronic inflammatory diseases

Chronic, noncommunicable, and inflammation-associated diseases remain the largest cause of morbidity and mortality globally and within the United States. This is mainly due to our limited understanding of the molecular mechanisms that underlie these complex pathologies. The available evidence indicates that studies of epigenetics (traditionally defined as the heritable changes to gene expression that are independent of changes to DNA) are significantly advancing our knowledge of these inflammatory conditions. This review will focus on epigenetic studies of three diseases, that are among the most burdensome globally: cardiovascular disease, the number one cause of deaths worldwide, type 2 diabetes and, Alzheimer’s disease. The current status of epigenetic research, including the ability to predict disease risk, and key pathophysiological defects are discussed. The significance of defining the contribution of epigenetic defects to nonresolving inflammation and aging, each associated with these diseases, is highlighted, as these are likely to provide new insights into inflammatory disease pathogenesis.

Circulating miRNA-33: a potential biomarker in patients with coronary artery disease

BACKGROUND

Circulating microRNAs (miRNA) are present in body fluids in stable, cell-free form. Likewise, these miRNAs can be identified in various stages of coronary artery disease (CAD) such as inflammation, endothelial dysfunction, proliferation and atherosclerosis among others. miRNA expression levels can be identified.

AIMS AND OBJECTIVES

To determine the expression of circulating miRNAs (miR-126, miR-92, miR-33, miR-145 and miR-155) in CAD patients of Indian origin.

MATERIAL AND METHODS

miRNA profiling analysis in blood plasma was performed by quantitative real-time-PCR (qRT-PCR) in 60 angiographically verified subjects including 30 CAD patients and 30 age- and gender-matched controls. Association between the expression of all five circulating miRNAs and clinical characteristics of patients with CAD were analysed using Medcalc statistics. The severity of CAD was assessed using SYNTAX score (SS).

RESULTS

Expression of plasma miR-33 increased by 2.9 folds in CAD patients than in control group (p value ≥0.002) also it was found that miR-33 expression levels in mild cases (SS: ≤22) were significantly higher than CAD controls. There was a modest negative correlation between miR-33 and total cholesterol/high density lipoprotein ratio, triglycerides and very low density lipoprotein.

CONCLUSION

The study reports a significant association between increased levels of plasma miR-33 and CAD. Thus, plasma miR-33 appears to be a promising non-invasive biomarker, but requires further validation in a large cohort.

Atherosclerotic plaque instability in carotid arteries: miR-200c as a promising biomarker

Early recognition of vulnerable carotid plaques could help in identifying patients at high stroke risk, who may benefit from earlier revascularisation. Nowadays, different biomarkers of plaque instability have been unravelled, among these miRNAs are promising tools for the diagnosis and treatment of atherosclerosis. Inflammation, reactive oxygen species (ROS) and endothelial dysfunction play a key role in unstable plaques genesis. We showed that miR-200c induces endothelial dysfunction, ROS production and a positive mechanism among miR-200c and miR-33a/b, two miRNAs involved in atherosclerosis progression. The goal of the present study was to determine whether miR-200c could be an atherosclerosis biomarker. Carotid plaques of patients that underwent carotid endarterectomy (CEA) were assayed for miR-200c expression. miR-200c was up-regulated in carotid plaques (n=22) and its expression was higher in unstable (n=12) compared with stable (n=10) plaques. miR-200c positively correlated with instability biomarkers (i.e. monocyte chemoattractant protein-1, cicloxigenase-2 (COX2), interleukin 6 (IL6), metalloproteinase (MMP) 1 (MMP1), 9 (MMP9)) and miR-33a/b. Moreover, miR-200c negatively correlated with stability biomarkers (i.e. zinc finger E-box binding homoeobox 1 (ZEB1), endothelial nitric oxide (NO) synthase (eNOS), forkhead boxO1 (FOXO1) and Sirtuin1 (SIRT1)) (stable plaques = 15, unstable plaques = 15). Circulating miR-200c was up-regulated before CEA in 24 patients, correlated with miR-33a/b and decreased 1 day after CEA. Interestingly, 1 month after CEA, circulating miR-200c is low in patients with stable plaques (n=11) and increased to control levels, in patients with unstable plaques (n=13). Further studies are needed to establish whether miR-200c represents a circulating biomarker of plaque instability. Our results show that miR-200c is an atherosclerotic plaque progression biomarker and suggest that it may be clinically useful to identify patients at high embolic risk.

Expression of TLR4-PTGE2 signaling genes in atherosclerotic carotid plaques and peripheral blood

Toll-like receptor 4 (TLR4)/prostaglandine synthetase 2 (PTGS2) signaling plays a relevant role in atherosclerotic plaque vulnerability. The purpose of this study was to check the gene expression of 6 genes participating to TLR4/PTGS2 signaling (TLR4, PTGS2, ACSL4, PTGER3, PTGER4, and EPRAP) in carotid plaques and blood samples from the same individual and to evaluate these genes as biomarker of plaque progression. We investigated differential gene expression by qRT-PCR in 62 atherosclerotic patients' carotid plaques and corresponding blood sample. A very weak or no correlation was observed in the overall population or analyzing asymptomatic patients. These analyzed genes are most likely not suitable for inclusion in the clinical routine as biomarkers of plaque instability.

Macrophage MicroRNAs as Therapeutic Targets for Atherosclerosis, Metabolic Syndrome, and Cancer

Macrophages play a crucial role in the innate immune system and contribute to a broad spectrum of pathologies in chronic inflammatory diseases. MicroRNAs (miRNAs) have been demonstrated to play important roles in macrophage functions by regulating macrophage polarization, lipid metabolism and so on. Thus, miRNAs represent promising diagnostic and therapeutic targets in immune disorders. In this review, we will summarize the role of miRNAs in atherosclerosis, metabolic syndrome, and cancer by modulating macrophage phenotypes, which has been supported by in vivo evidence.

miRNAs as potential therapeutic targets and diagnostic biomarkers for cardiovascular disease with a particular focus on WO2010091204

INTRODUCTION

A number of miRNAs have been reported to be critically involved in the regulation of cardiovascular disease (CVDs). Therefore, the development of potent analogues/inhibitors for miRNAs have thus become a key focus in the present drug discovery. In this review, we discuss the basic research and clinical use of miRNAs as the early diagnosis and therapeutic targets for CVD. We have also focused on the efficiency of therapeutically targeting miR-499, which is considered as one of the most promising molecules for treating CVDs. Areas covered: In this review, we have discussed the patents and patent applications related to miRNAs detected in CVD patients published in recent years. This review also covers the expression pattern of miR-499, as well as it highlights functions of its inhibitors in CVD. We used Google and Pubmed search engines to find relevant patents. Expert opinion: Although a massive number of miRNAs are patented as CVD biomarkers, further work is absolutely required to evaluate the reliable diagnostic values and therapeutic potential of these candidates. Overall, targeting miRNAs is definitely a promising strategy to be investigated for diagnosis and treatment of CVDs in future, however, the delivery system and off-targets effects are still a difficult challenge need to be elucidated.