MicroRNAs in vascular and metabolic disease

Endothelial dysfunction and platelet hyperactivity in type 2 diabetes mellitus: molecular insights and therapeutic strategies

The incidence and prevalence of diabetes mellitus is rapidly increasing worldwide at an alarming rate. Type 2 diabetes mellitus (T2DM) is the most prevalent form of diabetes, accounting for approximately 90-95% of the total diabetes cases worldwide. Besides affecting the ability of body to use glucose, it is associated with micro-vascular and macro-vascular complications. Augmented atherosclerosis is documented to be the key factor leading to vascular complications in T2DM patients. The metabolic milieu of T2DM, including insulin resistance, hyperglycemia and release of excess free fatty acids, along with other metabolic abnormalities affects vascular wall by a series of events including endothelial dysfunction, platelet hyperactivity, oxidative stress and low-grade inflammation. Activation of these events further enhances vasoconstriction and promotes thrombus formation, ultimately resulting in the development of atherosclerosis. All these evidences are supported by the clinical trials reporting the importance of endothelial dysfunction and platelet hyperactivity in the pathogenesis of atherosclerotic vascular complications. In this review, an attempt has been made to comprehensively compile updated information available in context of endothelial and platelet dysfunction in T2DM.

Non-coding RNAs in cardiovascular diseases: diagnostic and therapeutic perspectives

Recent research has demonstrated that the non-coding genome plays a key role in genetic programming and gene regulation during development as well as in health and cardiovascular disease. About 99% of the human genome do not encode proteins, but are transcriptionally active representing a broad spectrum of non-coding RNAs (ncRNAs) with important regulatory and structural functions. Non-coding RNAs have been identified as critical novel regulators of cardiovascular risk factors and cell functions and are thus important candidates to improve diagnostics and prognosis assessment. Beyond this, ncRNAs are rapidly emgerging as fundamentally novel therapeutics. On a first level, ncRNAs provide novel therapeutic targets some of which are entering assessment in clinical trials. On a second level, new therapeutic tools were developed from endogenous ncRNAs serving as blueprints. Particularly advanced is the development of RNA interference (RNAi) drugs which use recently discovered pathways of endogenous short interfering RNAs and are becoming versatile tools for efficient silencing of protein expression. Pioneering clinical studies include RNAi drugs targeting liver synthesis of PCSK9 resulting in highly significant lowering of LDL cholesterol or targeting liver transthyretin (TTR) synthesis for treatment of cardiac TTR amyloidosis. Further novel drugs mimicking actions of endogenous ncRNAs may arise from exploitation of molecular interactions not accessible to conventional pharmacology. We provide an update on recent developments and perspectives for diagnostic and therapeutic use of ncRNAs in cardiovascular diseases, including atherosclerosis/coronary disease, post-myocardial infarction remodelling, and heart failure.

Endothelial cell activation is attenuated by everolimus via transcriptional and post-transcriptional regulatory mechanisms after drug-eluting coronary stenting

We previously found higher level of endothelial cell (EC) activation in patients who suffered from in-stent restenosis after bare-metal stenting compared to subjects who underwent drug-eluting stenting (DES) showing no complications. Here we investigated the potential transcriptional and post-transcriptional regulatory mechanisms by which everolimus attenuated EC activation after DES. We studied the effect of everolimus on E-selectin (SELE) and VCAM1 mRNA levels when human coronary artery (HCAECs) and human umbilical vein ECs were challenged with recombinant TNF-α (100 ng/mL) for 1–24 hours in the presence or absence of everolimus using 0.5 μM concentration locally maintained by DES. EC activation was evaluated via the levels of IL-1β and IL-6 mRNAs with miR-155 expression by RT-qPCR as well as the nuclear translocation of nuclear factor kappa beta (NF-κB) detected by fluorescence microscopy. To investigate the transcriptional regulation of E-selectin and VCAM-1, TNF-α-induced enhancer RNA (eRNA) expression at p65-bound enhancers in the neighboring genomic regions of SELE and VCAM1 genes, including SELE_-11Kb and VCAM1_-10Kb, were measured in HCAECs. Mature and precursor levels of E-selectin and VCAM-1 repressor miR-181b were quantified to analyze the post-transcriptional regulation of these genes in HCAECs. Circulating miR-181b was analyzed in plasma samples of stented subjects by stem-loop RT-qPCR. TNF-α highly elevated E-selectin and VCAM-1 expression at transcriptional level in ECs. Levels of mature, pre- and pri-miR-181b were repressed in ECs by TNF-α, while everolimus acted as a negative regulator of EC activation via inhibited translocation of NF-κB p65 subunit into cell nuclei, lowered eRNA expression at SELE and VCAM1 genes-associated enhancers and modulated expression of their post-transcriptional repressor miR-181b. Significant negative correlation was observed between plasma miR-181b and soluble E-selectin and VCAM-1 in patients. In conclusion, everolimus attenuates EC activation via reduced NF-κB p65 translocation causing decreased E-selectin and VCAM-1 expression at transcriptional and post-transcriptional level after DES.

Molecular Regulatory Pathways Link Sepsis With Metabolic Syndrome: Non-coding RNA Elements Underlying the Sepsis/Metabolic Cross-Talk

Sepsis and metabolic syndrome (MetS) are both inflammation-related entities with high impact for human health and the consequences of concussions. Both represent imbalanced parasympathetic/cholinergic response to insulting triggers and variably uncontrolled inflammation that indicates shared upstream regulators, including short microRNAs (miRs) and long non-coding RNAs (lncRNAs). These may cross talk across multiple systems, leading to complex molecular and clinical outcomes. Notably, biomedical and RNA-sequencing based analyses both highlight new links between the acquired and inherited pathogenic, cardiac and inflammatory traits of sepsis/MetS. Those include the HOTAIR and MIAT lncRNAs and their targets, such as miR-122, −150, −155, −182, −197, −375, −608 and HLA-DRA. Implicating non-coding RNA regulators in sepsis and MetS may delineate novel high-value biomarkers and targets for intervention.

Dynamic Regulation of Circulating microRNAs During Acute Exercise and Long-Term Exercise Training in Basketball Athletes

Emerging evidence indicates the beneficial effects of physical exercise on human health, which depends on the intensity, training time, exercise type, environmental factors, and the personal health status. Conventional biomarkers provide limited insight into the exercise-induced adaptive processes. Circulating microRNAs (miRNAs, miRs) are dynamically regulated in response to acute exhaustive exercise and sustained rowing, running and cycling exercises. However, circulating miRNAs in response to long-term basketball exercise remains unknown. Here, we enrolled 10 basketball athletes who will attend a basketball season for 3 months. Specifically, circulating miRNAs which were involved in angiogenesis, inflammation and enriched in muscle and/or cardiac tissues were analyzed at baseline, immediately following acute exhaustive exercise and after 3-month basketball matches in competitive male basketball athletes. Circulating miR-208b was decreased and miR-221 was increased after 3-month basketball exercise, while circulating miR-221, miR-21, miR-146a, and miR-210 were reduced at post-acute exercise. The change of miR-146a (baseline vs. post-acute exercise) showed linear correlations with baseline levels of cardiac marker CKMB and the changes of inflammation marker Hs-CRP (baseline vs. post-acute exercise). Besides, linear correlation was observed between miR-208b changes (baseline vs. after long-term exercise) and AT VO₂ (baseline). The changes of miR-221 (baseline vs. after long-term exercise) were significantly correlated with AT VO₂, peak work load and CK (after 3-month basketball matches). Although further studies are needed, present findings set the stage for defining circulating miRNAs as biomarkers and suggesting their physiological roles in long-term exercise training induced cardiovascular adaptation.

Sex-dependent changes in lipid metabolism, PPAR pathways and microRNAs that target PPARs in the fetal liver of rats with gestational diabetes

Gestational diabetes mellitus (GDM) is a prevalent disease that impairs fetal metabolism and development. We have previously characterized a rat model of GDM induced by developmental programming. Here, we analyzed lipid content, the levels of the three PPAR isotypes and the expression of microRNAs that regulate PPARs expression in the liver of male and female fetuses of control and GDM rats on day 21 of pregnancy. We found increased levels of triglycerides and cholesterol in the livers of male fetuses of GDM rats compared to controls, and, oppositely, reduced levels of triglycerides, cholesterol, phospholipids and free fatty acids in the livers of female fetuses of GDM rats compared to controls. Although GDM did not change PPARα levels in male and female fetal livers, PPARγ was increased in the liver of male fetuses of GDM rats, a change that occurred in parallel to a reduction in the expression of miR-130, a microRNA that targets PPARγ. In livers of female fetuses of GDM rats, no changes in PPARγ and miR-130 were evidenced, but PPARδ was increased, a change that occurred in parallel to a reduction in the expression of miR-9, a microRNA that targets PPARδ, and was unchanged in the liver of male fetuses of GDM and control rats. These results show clear sex-dependent changes in microRNAs that target different PPAR isotypes in relation to changes in the levels of their targets and the differential regulation of lipid metabolism evidenced in fetal livers of GDM pregnancies.

The relationship between myocardial fibrosis and myocardial microRNAs in dilated cardiomyopathy: A link between mir-133a and cardiovascular events

It is unknown whether fibrosis‐associated microRNAs: miR‐21, miR‐26, miR‐29, miR‐30 and miR‐133a are linked to cardiovascular (CV) outcome. The study evaluated the levels of extracellular matrix (ECM) fibrosis and the prevalence of particular microRNAs in patients with dilated cardiomyopathy (DCM) to investigate any correlation with CV events. Methods: Seventy DCM patients (48 ± 12 years, EF 24.4 ± 7.4%) underwent right ventricular biopsy. The control group was comprised of 7 patients with CAD who underwent CABG and intraoperative biopsy. MicroRNAs were measured in blood and myocardial tissue via qPCR. The end‐point was a combination of CV death and urgent HF hospitalization at the end of 12 months. There were differential levels of circulating and myocardial miR‐26 and miR‐29 as well as myocardial miR‐133a when the DCM and CABG groups were compared. Corresponding circulating and myocardial microRNAs did not correlate with one another. There was no correlation between microRNA and ECM fibrosis. By the end of the 12‐month period of the study, CV death had occurred in 6 patients, and a further 19 patients required urgent HF hospitalization. None of the circulating microRNAs was a predictor of the combined end‐point; however, myocardial miR‐133a was an independent predictor in unadjusted models (HR 1.53; 95% CI 1.14‐2.05; P < .004) and adjusted models (HR 1.57; 95% CI 1.14‐2.17; P < .005). The best cut‐off value for the miR‐133a level for the prediction of the combined end‐point was 0.74 ΔCq, with an AUC of 0.67. The absence of a correlation between the corresponding circulating and myocardial microRNAs calls into question their cellular source. This study sheds new light on the role of microRNAs in ECM fibrosis in DCM, which warrants further exploration.

MicroRNA-145 regulates disabled-2 and Wnt3a expression in cardiomyocytes under hyperglycaemia

AIMS

MicroRNA-145 (miR-145) could protect cardiomyocyte apoptosis against oxidative stress and repair infarcted myocardium. Angiotensin II (Ang II), a pro-inflammatory cytokine could modulate myocardial remodelling. However, the role of hyperglycaemia on miR-145 expression in cardiomyocyte or diabetes is not known. The effect of Ang II on miR-145 expression under hyperglycaemia in cardiomyocytes remains unknown. We sought to investigate the effect of hyperglycaemia and Ang II on miR-145 expression in cardiomyocytes.

METHODS

Rat cardiomyocytes were cultured under high glucose concentration (25 mmol/L), and streptozotocin-induced diabetic rats were established. TaqMan^® MicroRNA real-time quantitative assay was used to quantitate miR-145.

RESULTS

Sustained high glucose concentration (hyperglycaemia) significantly decreased miR-145 expression in cardiomyocytes. Hyperglycaemia significantly increased Ang II mRNA expression and secretion from rat cardiomyocytes. Ang II suppressed miR-145 expression in cardiomyocytes. Hyperglycaemia increased Dab2 and decreased Wnt3a/ß-catenin expression in cardiomyocytes. Repression of miR-145 expression by Ang II resulted in increased Dab2 and decreased Wnt3a and ß-catenin expression under hyperglycaemia. In contrast, overexpression of miR-145 significantly decreased Dab2 mRNA and protein expression, whereas the mRNA and protein levels for Wnt3a and ß-catenin were significantly reduced in left ventricular myocardium from 5 days to 28 days in diabetic rats. The protein expression patterns of Dab2 and Wnt3a/ß-catenin in left ventricular myocardium of diabetic rats could be reversed upon treatment with valsartan.

CONCLUSIONS

Ang II downregulates miR-145 to regulate Dab2 and Wnt3a/ß-catenin expression in cardiomyocytes under high glucose concentration. Ang II plays a critical role in the regulation of miR-145 in cardiomyocytes under hyperglycaemic conditions.

Extracellular vesicles and cardiovascular disease therapy

Cardiovascular disease (CVD) constitutes one of the leading causes of mortality worldwide, therefore representing a major public health concern. Despite recent advances in the treatment of patients with acute myocardial infarction (AMI), such as bypass surgery or percutaneous coronary intervention, pathological cardiac remodeling often predisposes survivors to fatal heart failure. In this context, the proven efficacy of stem cell-regenerative therapies constitutes a promising therapeutic perspective with is nevertheless slow down by safety and ethical concerns. Recent studies have underscored the capacity of stem cell-derived extracellular vesicles (EV) to recapitulate the regenerative properties of their parental cells therefore offering a therapeutic alternative to cell therapy in cardiovascular regenerative medicine. In this article, we review the functional relevance of using stem cell-derived EV as therapeutically agents and detail the identified molecular pathways that they used to exert their effects. We also discuss the advantages of using such an acellular regenerative therapy, in regard with parental stem cells, and address the limitations, which would need to be resolved, before their clinical translation.

MicroRNA-27b Depletion Enhances Endotrophic and Intravascular Lipid Accumulation and Induces Adipocyte Hyperplasia in Zebrafish

miR-27b has emerged as a regulatory hub in cholesterol and lipid metabolism, and as a potential therapeutic target for treating atherosclerosis and obesity. However, the impact of miR-27b on lipid levels in vivo remains to be determined. Zebrafish lipids are normally stored as triacylglycerols (TGs) and their main storage sites are visceral, intramuscular, and subcutaneous lipid depots, and not blood vessels and liver. In this study, we applied microRNA-sponge (miR-SP) technology and generated zebrafish expressing transgenic miR-27b-SP (C27bSPs), which disrupted endogenous miR-27b activity and induced intravascular lipid accumulation (hyperlipidemia) and the early onset of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Oil Red O staining predominantly increased in the blood vessels and livers of larvae and juvenile C27bSPs, indicating that miR-27b depletion functionally promoted lipid accumulation. C27bSPs also showed an increased weight gain with larger fat pads, resulting from adipocyte hyperplasia. Molecular analysis revealed that miR-27b depletion increased the expression of genes that are associated with lipogenesis and the endoplasmic reticulum (ER). Moreover, miR-27b-SP increased peroxisome proliferator-activated receptor γ (PPAR-γ), CCAAT enhancer binding protein-α (C/EBP-α, and sterol regulatory element binding transcription factor 1c (SREBP-1c) expression and contributed to lipogenesis and adipogenesis.

CONCLUSION

Our results suggest that miR-27b-SP acts as a lipid enhancer by directly increasing the expression of several lipogenic/adipogenic transcriptional factors, resulting in increased lipogenesis and adipogenesis. In this study, miR-27b expression improved lipid metabolism in C27bSPs, which suggests that miR-27b is an important lipogenic factor in regulating early onset of hyperlipidemia and adipogenesis in zebrafish.

miR-22 Is a Novel Mediator of Vascular Smooth Muscle Cell Phenotypic Modulation and Neointima Formation

Supplemental Digital Content is available in the text.

Background:

MicroRNA-22 (miR-22) has recently been reported to play a regulatory role during vascular smooth muscle cell (VSMC) differentiation from stem cells, but little is known about its target genes and related pathways in mature VSMC phenotypic modulation or its clinical implication in neointima formation following vascular injury.

Methods:

We applied a wire-injury mouse model, and local delivery of AgomiR-22 or miR-22 inhibitor, as well, to explore the therapeutic potential of miR-22 in vascular diseases. Furthermore, normal and diseased human femoral arteries were harvested, and various in vivo, ex vivo, and in vitro models of VSMC phenotype switching were conducted to examine miR-22 expression during VSMC phenotype switching.

Results:

Expression of miR-22 was closely regulated during VSMC phenotypic modulation. miR-22 overexpression significantly increased expression of VSMC marker genes and inhibited VSMC proliferation and migration, whereas the opposite effect was observed when endogenous miR-22 was knocked down. As expected, 2 previously reported miR-22 target genes, MECP2 (methyl-CpG binding protein 2) and histone deacetylase 4, exhibited a regulatory role in VSMC phenotypic modulation. A transcriptional regulator and oncoprotein, EVI1 (ecotropic virus integration site 1 protein homolog), has been identified as a novel miR-22 target gene in VSMC phenotypic modulation. It is noteworthy that overexpression of miR-22 in the injured vessels significantly reduced the expression of its target genes, decreased VSMC proliferation, and inhibited neointima formation in wire-injured femoral arteries, whereas the opposite effect was observed with local application of a miR-22 inhibitor to injured arteries. We next examined the clinical relevance of miR-22 expression and its target genes in human femoral arteries. We found that miR-22 expression was significantly reduced, whereas MECP2 and EVI1 expression levels were dramatically increased, in diseased in comparison with healthy femoral human arteries. This inverse relationship between miR-22 and MECP2 and EVI1 was evident in both healthy and diseased human femoral arteries.

Conclusions:

Our data demonstrate that miR-22 and EVI1 are novel regulators of VSMC function, specifically during neointima hyperplasia, offering a novel therapeutic opportunity for treating vascular diseases.

MicroRNA-146a Mimics Reduce the Peripheral Neuropathy in Type 2 Diabetic Mice

MicroRNA-146a (miR-146a) regulates multiple immune diseases. However, the role of miR-146a in diabetic peripheral neuropathy (DPN) has not been investigated. We found that mice (db/db) with type 2 diabetes exhibited substantial downregulation of miR-146a in sciatic nerve tissue. Systemic administration of miR-146a mimics to diabetic mice elevated miR-146a levels in plasma and sciatic nerve tissue and substantially increased motor and sensory nerve conduction velocities by 29 and 11%, respectively, and regional blood flow by 50% in sciatic nerve tissue. Treatment with miR-146a mimics also considerably decreased the response in db/db mice to thermal stimuli thresholds. Histopathological analysis showed that miR-146a mimics markedly augmented the density of fluorescein isothiocyanate-dextran-perfused blood vessels and increased the number of intraepidermal nerve fibers, myelin thickness, and axonal diameters of sciatic nerves. In addition, miR-146a treatment reduced and increased classically and alternatively activated macrophage phenotype markers, respectively. Analysis of miRNA target array revealed that miR-146a mimics greatly suppressed expression of many proinflammatory genes and downstream related cytokines. Collectively, our data indicate that treatment of diabetic mice with miR-146a mimics robustly reduces DPN and that suppression of hyperglycemia-induced proinflammatory genes by miR-146a mimics may underlie its therapeutic effect.

Role of MicroRNAs in TGF-β Signaling Pathway-Mediated Pulmonary Fibrosis

Pulmonary fibrosis is the most common form of interstitial lung disease. The transforming growth factor-β (TGF-β) signaling pathway is extensively involved in the development of pulmonary fibrosis by inducing cell differentiation, migration, invasion, or hyperplastic changes. Accumulating evidence indicates that microRNAs (miRNAs) are dysregulated during the initiation of pulmonary fibrosis. miRNAs are small noncoding RNAs functioning as negative regulators of gene expression at the post-transcriptional level. A number of miRNAs have been reported to regulate the TGF-β signaling pathway and consequently affect the process of pulmonary fibrosis. A better understanding of the pro-fibrotic role of the TGF-β signaling pathway and relevant miRNA regulation will shed light on biomedical research of pulmonary fibrosis. This review summarizes the current knowledge of miRNAs regulating the TGF-β signaling pathway with relevance to pulmonary fibrosis.

Peptide Nucleic Acid-Based Biosensors for Cancer Diagnosis

The monitoring of DNA and RNA biomarkers freely circulating in the blood constitutes the basis of innovative cancer detection methods based on liquid biopsy. Such methods are expected to provide new opportunities for a better understanding of cancer disease at the molecular level, thus contributing to improved patient outcomes. Advanced biosensors can advance possibilities for cancer-related nucleic acid biomarkers detection. In this context, peptide nucleic acids (PNAs) play an important role in the fabrication of highly sensitive biosensors. This review provides an overview of recently described PNA-based biosensors for cancer biomarker detection. One of the most striking features of the described detection approaches is represented by the possibility to detect target nucleic acids at the ultra-low concentration with the capability to identify single-base mutations.

CRISPR/Cas9 editing reveals novel mechanisms of clustered microRNA regulation and function

MicroRNAs (miRNAs) are important regulators of diverse physiological and pathophysiological processes. MiRNA families and clusters are two key features in miRNA biology. Here we explore the use of CRISPR/Cas9 as a powerful tool to delineate the function and regulation of miRNA families and clusters. We focused on four miRNA clusters composed of miRNA members of the same family, homo-clusters or different families, hetero-clusters. Our results highlight different regulatory mechanisms in miRNA cluster expression. In the case of the miR-497~195 cluster, editing of miR-195 led to a significant decrease in the expression of the other miRNA in the cluster, miR-497a. Although no gene editing was detected in the miR-497a genomic locus, computational simulation revealed alteration in the three dimensional structure of the pri-miR-497~195 that may affect its processing. In cluster miR-143~145 our results imply a feed-forward regulation, although structural changes cannot be ruled out. Furthermore, in the miR-17~92 and miR-106~25 clusters no interdependency in miRNA expression was observed. Our findings suggest that CRISPR/Cas9 is a powerful gene editing tool that can uncover novel mechanisms of clustered miRNA regulation and function.

Kinetics of Circulating MicroRNAs in Response to Cardiac Stress in Patients With Coronary Artery Disease

Background

Circulating microRNAs (miRNAs/miRs) are regulated in patients with coronary artery disease. The impact of transient coronary ischemia on circulating miRNA levels is unknown. We aimed to investigate circulating miRNA kinetics in response to cardiac stress in patients with or without significant coronary stenosis.

Methods and Results

Eighty of 105 screened patients with stable coronary artery disease underwent dobutamine stress echocardiography before coronary angiography. Nine circulating vascular miRNAs (miRNA‐21, miRNA‐26, miRNA‐27a, miRNA‐92a, miRNA‐126‐3p, miRNA‐133a, miRNA‐222, miRNA‐223, and miRNA‐199‐5p) were quantified in plasma by reverse transcription polymerase chain reaction before, immediately after, and 4 and 24 hours after dobutamine stress echocardiography. Quantitative polymerase chain reaction revealed increased miRNA‐21, miRNA‐126‐3p, and miRNA‐222 levels at 24 hours after dobutamine stress echocardiography in all patients. On coronary angiography, significant coronary artery stenoses (>80% diameter stenosis) were found in 41 patients. Stratifying patients according to the prevalence of significant stenoses, patients with stenosis showed an increase of circulating miRNA‐21, miRNA‐126‐3p, and miRNA‐222 in response to cardiac stress. In patients without significant stenoses (<50% diameter stenosis), miRNA‐92a levels gradually increased in response to cardiac stress.

Conclusions

miRNAs are distinctly released into the circulation in response to cardiac stress depending on the prevalence of significant coronary stenoses.

RNA-Seq Identifies Circulating miR-125a-5p, miR-125b-5p, and miR-143-3p as Potential Biomarkers for Acute Ischemic Stroke

RATIONALE

Currently, there are no blood-based biomarkers with clinical utility for acute ischemic stroke (IS). MicroRNAs show promise as disease markers because of their cell type-specific expression patterns and stability in peripheral blood.

OBJECTIVE

To identify circulating microRNAs associated with acute IS, determine their temporal course up to 90 days post-stroke, and explore their utility as an early diagnostic marker.

METHODS AND RESULTS

We used RNA sequencing to study expression changes of circulating microRNAs in a discovery sample of 20 patients with IS and 20 matched healthy control subjects. We further applied quantitative real-time polymerase chain reaction in independent samples for validation (40 patients with IS and 40 matched controls), replication (200 patients with IS, 100 healthy control subjects), and in 72 patients with transient ischemic attacks. Sampling of patient plasma was done immediately upon hospital arrival. We identified, validated, and replicated 3 differentially expressed microRNAs, which were upregulated in patients with IS compared with both healthy control subjects (miR-125a-5p [1.8-fold; P=1.5×10^-6], miR-125b-5p [2.5-fold; P=5.6×10^-6], and miR-143-3p [4.8-fold; P=7.8×10^-9]) and patients with transient ischemic attack (miR-125a-5p: P=0.003; miR-125b-5p: P=0.003; miR-143-3p: P=0.005). Longitudinal analysis of expression levels up to 90 days after stroke revealed a normalization to control levels for miR-125b-5p and miR-143-3p starting at day 2 while miR-125a-5p remained elevated. Levels of all 3 microRNAs depended on platelet numbers in a platelet spike-in experiment but were unaffected by chemical hypoxia in Neuro2a cells and in experimental stroke models. In a random forest classification, miR-125a-5p, miR-125b-5p, and miR-143-3p differentiated between healthy control subjects and patients with IS with an area under the curve of 0.90 (sensitivity: 85.6%; specificity: 76.3%), which was superior to multimodal cranial computed tomography obtained for routine diagnostics (sensitivity: 72.5%) and previously reported biomarkers of acute IS (neuron-specific enolase: area under the curve=0.69; interleukin 6: area under the curve=0.82).

CONCLUSIONS

A set of circulating microRNAs (miR-125a-5p, miR-125b-5p, and miR-143-3p) associates with acute IS and might have clinical utility as an early diagnostic marker.

MicroRNAs in Cardiovascular Disease

Micro-ribonucleic acids (miRNAs) are in the spotlight as post-transcriptional regulators of gene expression. More than 1,000 miRNAs are encoded in the human genome. In this review, we provide an introduction to miRNA biology and research methodology, and highlight advances in cardiovascular research to date. This includes the potential of miRNAs as therapeutic targets in cardiac and vascular disease, and their use as novel biomarkers. Although some miRNA therapies are already undergoing clinical evaluation, we stress the importance of integrating current knowledge of miRNA biology into a systemic context. Discovery studies focus on miRNA effects within one specific organ, whereas the expression of most miRNAs is not restricted to a single tissue. Because most miRNA-based therapies act systemically, this may preclude widespread clinical use. The development of more targeted interventions will bolster well-informed clinical applications, increasing the chances of success and minimizing the risk of setbacks for miRNA-based therapeutics.

Incremental Value of Circulating MiR-122-5p to Predict Outcome after Out of Hospital Cardiac Arrest

Rationale. The value of microRNAs (miRNAs) as biomarkers has been addressed in various clinical contexts. Initial studies suggested that miRNAs, such as the brain-enriched miR-124-3p, might improve outcome prediction after out-of-hospital cardiac arrest. The aim of this study is to determine the prognostic value of miR-122-5p in a large cohort of comatose survivors of out-of-hospital cardiac arrest. Methods. We analyzed 590 patients from the Targeted Temperature Management trial (TTM-trial). Circulating levels of miR-122-5p were measured in serum samples obtained 48 hours after return of spontaneous circulation. The primary end-point was poor neurological outcome at 6 months evaluated by the cerebral performance category score. The secondary end-point was survival at the end of the trial. Results. Forty-eight percent of patients had a poor neurological outcome at 6 months and 43% were dead at the end of the trial. Levels of miR-122-5p were lower in patients with poor neurological outcome compared to patients with good neurological outcome (p<0.001), independently of targeted temperature management regimen. Levels of miR-122-5p were significant univariate predictors of neurological outcome (odds ratios (OR), 95% confidence intervals (CI): 0.71 [0.57-0.88]). In multivariable analyses, miR-122-5p was an independent predictor of neurological outcome and improved the predictive value of a clinical model including miR-124-3p (integrated discrimination improvement of 0.03 [0.02-0.04]). In Cox proportional hazards models, miR-122-5p was a significant predictor of survival at the end of the trial. Conclusion. Circulating levels of miR-122-5p improve the prediction of outcome after out-of-hospital cardiac arrest.

Targeting vascular (endothelial) dysfunction

Cardiovascular diseases are major contributors to global deaths and disability-adjusted life years, with hypertension a significant risk factor for all causes of death. The endothelium that lines the inner wall of the vasculature regulates essential haemostatic functions, such as vascular tone, circulation of blood cells, inflammation and platelet activity. Endothelial dysfunction is an early predictor of atherosclerosis and future cardiovascular events. We review the prognostic value of obtaining measurements of endothelial function, the clinical techniques for its determination, the mechanisms leading to endothelial dysfunction and the therapeutic treatment of endothelial dysfunction. Since vascular oxidative stress and inflammation are major determinants of endothelial function, we have also addressed current antioxidant and anti-inflammatory therapies. In the light of recent data that dispute the prognostic value of endothelial function in healthy human cohorts, we also discuss alternative diagnostic parameters such as vascular stiffness index and intima/media thickness ratio. We also suggest that assessing vascular function, including that of smooth muscle and even perivascular adipose tissue, may be an appropriate parameter for clinical investigations.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

miR-125a-5p Modulates Phenotypic Switch of Vascular Smooth Muscle Cells by Targeting ETS-1

MicroRNAs are key regulators of vascular smooth muscle cells (VSMCs) phenotypic switch, one of the main events responsible for bare metal in-stent restenosis after percutaneous coronary intervention. miR-125a-5p is an important modulator of differentiation, proliferation, and migration in different cell types; however, its role in VSMCs is still unknown. The aim of this study was to evaluate the role of miR-125a-5p in VSMCs phenotypic switch. Our results suggest that miR-125a-5p is highly expressed in VSMCs, but it is down-regulated after vascular injury in vivo. Its overexpression is sufficient to reduce VSMCs proliferation and migration, and it is able to promote the expression of selective VSMCs markers such as alpha smooth muscle actin, myosin heavy chain 11, and smooth muscle 22 alpha. Interestingly, miR-125a-5p directly targets ETS-1, a transcription factor implicated in cell proliferation and migration and is crucial in PDGF-BB pathway in VSMCs. Thus, miR-125a-5p in this context inhibits PDGF-BB pathway and is therefore a potential regulator of VSMCs phenotypic switch.

microRNAs in cardiovascular disease - clinical application

microRNAs (miRNAs) are well-known, powerful regulators of gene expression, and their potential to serve as circulating biomarkers is widely accepted. In cardiovascular disease (CVD), numerous studies have suggested miRNAs as strong circulating biomarkers with high diagnostic as well as prognostic power. In coronary artery disease (CAD) and heart failure (HF), miRNAs have been suggested as reliable biomarkers matching up to established protein-based such as cardiac troponins (cT) or natriuretic peptides. Also, in other CVD entities, miRNAs were identified as surprisingly specific biomarkers - with great potential for clinical applicability, especially in those entities that lack specific protein-based biomarkers such as atrial fibrillation (AF) and acute pulmonary embolism (APE). In this regard, miRNA signatures, comprising a set of miRNAs, yield high sensitivity and specificity. Attempts to utilize miRNAs as therapeutic agents have led to promising results. In this article, we review the clinical applicability of circulating miRNAs in CVD. We are giving an overview of miRNAs as biomarkers in numerous CVD entities to depict the variety of their potential clinical deployment. We illustrate the function of miRNAs by means of single miRNA examples in CVD.

MiR-942 decreased before 20 weeks gestation in women with preeclampsia and was associated with the pathophysiology of preeclampsia in vitro

OBJECTIVE

To investigate the possible relationship between miR-942 levels and the pathogenesis of preeclampsia using in vitro assays and to investigate circulating miR-942 levels in the early phase of mid-of pregnancy in women who later developed preeclampsia and in women with uncomplicated pregnancies.

METHODS

Plasma samples were collected from pregnant women between 12 and 20 weeks of gestation. MiR-942 levels were determined by stem-loop real-time PCR for 26 cases who subsequently developed preeclampsia as well as for 52 controls. Bioinformatics software was used to predict the target genes of miR-942, and a dual-luciferase reporter system was utilized to validate target gene regulation. Finally, MTT proliferation assays, transwell invasion assays, and endothelial cell tube formation assays were performed to further explore the function of miR-942 using a human extravillous trophoblast cell line (TEV-1).

RESULT

Circulating miR-942 levels were significantly lower in mid-pregnancy (12-20 weeks gestation) in women who later developed preeclampsia compared with those with an uncomplicated pregnancy (p < 0.05). Endoglin (ENG) is an miR-942 target gene. MiR-942 had a sensitivity of 0.673, a specificity of 0.875, and an area under the receiver operating characteristic curve (AUC) of 0.718 [95% CI, 0.594-0.822] for the possible screening of preeclampsia. In vitro, decreased miR-942 expression decreased the invasive ability of TEV-1 cells, and inhibited the HUVEC angiogenesis assay, both effects that are similar to what is observed in preeclampsia (both p <0.05).

CONCLUSION

MiR-942 may be involved in the pathogenesis of preeclampsia via the regulation of its target gene ENG. Multicenter studies must be performed and a greater number of samples must be analyzed to ascertain whether circulating miR-942 levels can serve as a novel early diagnostic marker for preeclampsia.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

miRNAs: Nanomachines That Micromanage the Pathophysiology of Diabetes Mellitus

Diabetes mellitus (DM) refers to a combination of heterogeneous complex metabolic disorders that are associated with episodes of hyperglycemia and glucose intolerance occurring as a result of defects in insulin secretion, action, or both. The prevalence of DM is increasing at an alarming rate, and there exists a need to develop better therapeutics and prognostic markers for earlier detection and diagnosis. In this review, after giving a brief introduction of diabetes mellitus and microRNA (miRNA) biogenesis pathway, we first describe various in vitro and animal model systems that have been developed to study diabetes. Further, we elaborate on the significant roles played by miRNAs as regulators of gene expression in the context of development of diabetes and its secondary complications. The different approaches to quantify miRNAs and their potential to be used as therapeutic targets for alleviation of diabetes have also been discussed.

BioM2MetDisease: a manually curated database for associations between microRNAs, metabolites, small molecules and metabolic diseases

BioM2MetDisease is a manually curated database that aims to provide a comprehensive and experimentally supported resource of associations between metabolic diseases and various biomolecules. Recently, metabolic diseases such as diabetes have become one of the leading threats to people’s health. Metabolic disease associated with alterations of multiple types of biomolecules such as miRNAs and metabolites. An integrated and high-quality data source that collection of metabolic disease associated biomolecules is essential for exploring the underlying molecular mechanisms and discovering novel therapeutics. Here, we developed the BioM2MetDisease database, which currently documents 2681 entries of relationships between 1147 biomolecules (miRNAs, metabolites and small molecules/drugs) and 78 metabolic diseases across 14 species. Each entry includes biomolecule category, species, biomolecule name, disease name, dysregulation pattern, experimental technique, a brief description of metabolic disease-biomolecule relationships, the reference, additional annotation information etc. BioM2MetDisease provides a user-friendly interface to explore and retrieve all data conveniently. A submission page was also offered for researchers to submit new associations between biomolecules and metabolic diseases. BioM2MetDisease provides a comprehensive resource for studying biology molecules act in metabolic diseases, and it is helpful for understanding the molecular mechanisms and developing novel therapeutics for metabolic diseases.

Database URL

http://www.bio-bigdata.com/BioM2MetDisease/.

Droplet Microfluidic Device Fabrication and Use for Isothermal Amplification and Detection of MicroRNA

Droplet microfluidics combined with the isothermal circular strand displacement polymerization (ICSDP) represents a powerful new technique to detect both single-stranded DNA and microRNA sequences. The method here described helps in overcoming some drawbacks of the lately introduced droplet polymerase chain reaction (PCR) amplification when implemented in microfluidic devices. The method also allows the detection of nanoliter droplets of nucleic acids sequences solutions, with a particular attention to microRNA sequences that are detected at the picomolar level. The integration of the ICSDP amplification protocol in droplet microfluidic devices reduces the time of analysis and the amount of sample required. In addition, there is also the possibility to design parallel analyses to be integrated in portable devices.

Metformin is not just an antihyperglycaemic drug but also has protective effects on the vascular endothelium

Metformin, a synthetic dimethyl biguanide, has been in clinical use for over 55 years, and today is considered the first-choice drug for the treatment of type 2 diabetes used by an estimated 125 million people worldwide. Metformin is orally effective, not metabolized, excreted unchanged by the kidney, relatively free of side effects and well tolerated by the majority of patients. Of importance is that the United Kingdom Prospective Diabetes Study 20-year study of type 2 diabetics, completed in 1998, compared patients treated with insulin, sulfonylureas and metformin and concluded that metformin provided vascular protective actions. Cardiovascular disease is the primary basis for the high morbidity and mortality that is associated with diabetes and that metformin proved to be protective resulted in a dramatic increase in its use. The vascular protective actions of metformin are thought to be secondary to the antihyperglycaemic effects of metformin that are mediated via activation of AMP kinase and subsequent inhibition of hepatic gluconeogenesis, fatty acid oxidation as well as an insulin sensitizing action in striated muscle and adipose tissue. As reflected by a number of clinical studies, patients treated with metformin also have improvement in endothelial function as measured by the use of plethysmography and measurement of flow-mediated vasodilatation. These data as well as data from animal studies are supportive that metformin has a direct protective action on the vascular endothelium. In this review article, we discuss the pharmacology of metformin and critique the literature as to its cellular sites and mechanism(s) of action.

MicroRNAs 33, 122, and 208: a potential novel targets in the treatment of obesity, diabetes, and heart-related diseases

Despite decades of research, obesity and diabetes remain major health problems in the USA and worldwide. Among the many complications associated with diabetes is an increased risk of cardiovascular diseases, including myocardial infarction and heart failure. Recently, microRNAs have emerged as important players in heart disease and energy regulation. However, little work has investigated the role of microRNAs in cardiac energy regulation. Both human and animal studies have reported a significant increase in circulating free fatty acids and triacylglycerol, increased cardiac reliance on fatty acid oxidation, and subsequent decrease in glucose oxidation which all contributes to insulin resistance and lipotoxicity seen in obesity and diabetes. Importantly, MED13 was initially identified as a negative regulator of lipid accumulation in Drosophilia. Various metabolic genes were downregulated in MED13 transgenic heart, including sterol regulatory element-binding protein. Moreover, miR-33 and miR-122 have recently revealed as key regulators of lipid metabolism. In this review, we will focus on the role of microRNAs in regulation of cardiac and total body energy metabolism. We will also discuss the pharmacological and non-pharmacological interventions that target microRNAs for the treatment of obesity and diabetes.

miR-146a-mediated suppression of the inflammatory response in human adipocytes

The obesity-associated inflammation of white adipose tissue (WAT) is one of the factors leading to the development of related diseases such as insulin resistance and liver steatosis. Recently, microRNAs (miRNAs) were identified as important regulators of WAT functions. Herein, we cultured human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes with macrophage-conditioned medium (MacCM) and performed an Affimetrix miRNA array to identify miRNAs differentially expressed under inflammatory conditions. We identified 24 miRNAs differentially expressed upon inflammation in human adipocytes and miR-146a was the most up-regulated miRNA species. In subcutaneous WAT, miR-146a was elevated in both human and murine obesity. Transfection of miR-146a mimics prevented the MacCM-induced inflammatory response in SGBS adipocytes as seen by reduced levels of IL-8 and MCP-1 mRNA and protein. We identified IRAK1 and TRAF6 as targets of miR-146a in human adipocytes and detected a reduced inflammation-induced activation of JNK and p38 upon miR-146a transfection. Taken together, we could show that miR-146a reduces the inflammatory response in human adipocytes. In a negative feedback loop miR-146a might contribute to the regulation of inflammatory processes in WAT and possibly prevent an overwhelming inflammatory response.

Understanding the epigenetic regulation of tumours and their microenvironments: opportunities and problems for epigenetic therapy

The tumour microenvironment plays an instrumental role in cancer development, progression and treatment response/resistance. Accumulating evidence is underscoring the fundamental importance of epigenetic regulation in tumour immune evasion. Following many pioneering discoveries demonstrating malignant transformation through epigenetic anomalies ('epimutations'), there is also a growing emphasis on elucidating aberrant epigenetic mechanisms that reprogramme the milieu of tumour-associated immune and stromal cells towards an immunosuppressive state. Pharmacological inhibition of DNA methylation and histone modifications can augment the efficiency of immune checkpoint blockage, and unleash anti-tumour T-cell responses. However, these non-specific agents also represent a 'double-edged sword', as they can also reactivate gene transcription of checkpoint molecules, interrupting immune surveillance programmes. By understanding the impact of epigenetic control on the tumour microenvironment, rational combinatorial epigenetic and checkpoint blockage therapies have the potential to harness the immune system for the treatment of cancer. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Integrated microRNA and messenger RNA analysis in aortic stenosis

Aortic valve stenosis (AS) is a major cause of morbidity and mortality, with no effective medical therapies. Investigation into the underlying biology of AS in humans is limited by difficulties in obtaining healthy valvular tissue for use as a control group. However, micro-ribonucleic acids (miRNAs) are stable in post-mortem tissue. We compared valve specimens from patients undergoing aortic valve replacement for AS to non-diseased cadaveric valves. We found 106 differentially expressed miRNAs (p < 0.05, adjusted for multiple comparisons) on microarray analysis, with highly correlated expression among up- and down-regulated miRNAs. Integrated miRNA/gene expression analysis validated the microarray results as a whole, while quantitative polymerase chain reaction confirmed downregulation of miR-122-5p, miR-625-5p, miR-30e-5p and upregulation of miR-21-5p and miR-221-3p. Pathway analysis of the integrated miRNA/mRNA network identified pathways predominantly involved in extracellular matrix function. A number of currently available therapies target products of upregulated genes in the integrated miRNA/mRNA network, with these genes being predominantly more peripheral members of the network. The identification of a group of tissue miRNA associated with AS may contribute to the development of new therapeutic approaches to AS. This study highlights the importance of systems biology-based approaches to complex diseases.

Nanofiber-mediated microRNA-126 delivery to vascular endothelial cells for blood vessel regeneration

As manipulation of gene expression by virtue of microRNAs (miRNAs) is one of the emerging strategies for cardiovascular disease remedy, local delivery of miRNAs to a specific vascular tissue is challenging. In this work, we developed an efficient delivery system composed of electrospun fibrous membranes and target carriers for the intracellular delivery of miRNA-126 (miR-126) to vascular endothelial cells (VECs) in the local specific vascular environment. A bilayer vascular scaffold was specially prepared via emulsion electrospinning of poly(ethylene glycol)-b-poly(l-lactide-co-ε-caprolactone) (PELCL) and dual-power electrospinning of poly(ε-caprolactone) (PCL) and gelatin. The inner layer of PELCL, which was loaded with complexes of miR-126 in REDV peptide-modified trimethyl chitosan-g-poly(ethylene glycol), regulated the response of VECs, while the outer layer of PCL/gelatin contributed to the mechanical stability. Biological activities of the miR-126-loaded electrospun membranes were evaluated by cell proliferation and SPRED-1 expression of a miR-126 target gene. By encapsulating targeting complexes of miR-126 in the electrospun membranes, a sustained release profile of miRNA was obtained for 56days. Significant down-regulation of SPRED-1 gene expression in VECs was detected on day 3, and it was found that miR-126 released from the electrospun membranes accelerated VEC proliferation in the first 9days. The bilayer vascular scaffold loaded with miR-126 complexes could also improve endothelialization in vivo. These results demonstrated the potential of this approach towards a new and more effective delivering system for local delivery of miRNAs to facilitate blood vessel regeneration.

STATEMENT OF SIGNIFICANCE

Tissue engineering of small-diameter blood vessels is still challenging because of thrombosis and low long-term patency. The manipulation of gene expression by miRNAs could be a novel strategy in vascular regeneration. Here, we report an efficient delivery system of electrospun fibrous scaffold combined with REDV peptide-modified trimethyl chitosan for targeted intracellular delivery of miR-126 to VECs in the local vascular environment. Results exhibited that miR-126 released from the electrospun membrane could modulate VEC proliferation via down-regulation of SPRED-1 gene expression. The electrospun scaffolds loaded with target-delivery carriers may serve as an ideal platform for local delivery of miRNAs in the vascular tissue engineering.

Post-transcriptional Regulation of BRCA2 through Interactions with miR-19a and miR-19b

Breast cancer type 2, early onset susceptibility gene (BRCA2) is a major component of the homologous recombination DNA repair pathway. It acts as a tumor suppressor whose function is often lost in cancers. Patients with specific mutations in the BRCA2 gene often display discrete clinical, histopathological, and molecular features. However, a subset of sporadic cancers has wild type BRCA2 and display defects in the homology-directed repair pathway, which is the hallmark of ‘BRCAness.’ The mechanisms by which BRCAness arises are not well understood but post-transcriptional regulation of BRCA2 gene expression by microRNAs (miRNAs) may contribute to this phenotype. Here, we examine the post-transcriptional effects that some members of the six-miRNA cluster known as the miR-17/92 cluster have on the abundance of BRCA2’s messenger RNA (mRNA) and protein. We discuss two interactions involving the miR-19a and miR-19b members of the cluster and the 3′UTR of BRCA2’s mRNA. We investigated these miRNA:mRNA interactions in 15 cell lines derived from pancreatic, breast, colon, and kidney tissue. We show that over-expression of these two miRNAs results in a concomitant decrease of BRCA2’s mRNA and protein expression in a subset of the tested cell lines. Additionally, using luciferase reporter assays we identified direct interactions between miR-19a/miR-19b and a miRNA response element (MRE) in BRCA2’s 3′UTR. Our results suggest that BRCA2 is subject to a complex post-transcriptional regulatory program that has specific dependencies on the genetic and phenotypic background of cell types.

Identification of miRNAs Potentially Involved in Bronchiolitis Obliterans Syndrome: A Computational Study

The pathogenesis of Bronchiolitis Obliterans Syndrome (BOS), the main clinical phenotype of chronic lung allograft dysfunction, is poorly understood. Recent studies suggest that epigenetic regulation of microRNAs might play a role in its development. In this paper we present the application of a complex computational pipeline to perform enrichment analysis of miRNAs in pathways applied to the study of BOS. The analysis considered the full set of miRNAs annotated in miRBase (version 21), and applied a sequence of filtering approaches and statistical analyses to reduce this set and to score the candidate miRNAs according to their potential involvement in BOS development. Dysregulation of two of the selected candidate miRNAs–miR-34a and miR-21 –was clearly shown in in-situ hybridization (ISH) on five explanted human BOS lungs and on a rat model of acute and chronic lung rejection, thus definitely identifying miR-34a and miR-21 as pathogenic factors in BOS and confirming the effectiveness of the computational pipeline.

Pancreas-enriched miRNAs are altered in the circulation of subjects with diabetes: a pilot cross-sectional study

The clinical presentation of diabetes sometimes overlaps, contributing to ambiguity in the diagnosis. Thus, circulating pancreatic islet-enriched microRNAs (miRNAs) might be useful biomarkers of β-cell injury/dysfunction that would allow more accurate subtyping of diabetes. We measured plasma levels of selected miRNAs in subjects with prediabetes (n = 12), type 2 diabetes (T2D, n = 31), latent autoimmune diabetes of adults (LADA, n = 6) and type 1 diabetes (T1D, n = 16) and compared them to levels in healthy control subjects (n = 27). The study was conducted at the Translational Research Institute for Metabolism and Diabetes (TRI-MD), Florida Hospital. MiRNAs including miR-375 (linked to β-cell injury), miR-21 (associated with islet inflammation), miR-24.1, miR-30d, miR-34a, miR-126, miR-146, and miR-148a were significantly elevated in subjects with various forms of diabetes compared to healthy controls. Levels of several miRNAs were significantly correlated with glucose responses during oral glucose tolerance testing, HbA_1c, β-cell function, and insulin resistance in healthy controls, prediabetes, and T2D. These data suggest that miRNAs linked to β-cell injury and islet inflammation might be useful biomarkers to distinguish between subtypes of diabetes. This information could be used to predict progression of the disease, guide selection of optimal therapy and monitor responses to interventions, thus improving outcomes in patients with diabetes.

microRNAs as cancer biomarkers

Since their discovery in 1993, microRNAs (miRNAs) have been identified as important gene regulators in many biological processes and as key molecular players in human disease, including cancer where they show specific pathogenic deregulation. Their remarkable chemical stability, the availability of very sensitive miRNA detection methods and the fact that miRNAs can be extracted from and detected in various kinds of clinically relevant samples, such as solid tissues, body fluids and secretions make them excellent candidate biomarkers. However, no miRNA has yet entered the level of practical clinical relevance. We present a brief background and some key aspects and challenges of miRNAs as cancer biomarkers, we discuss shortfalls and identify possible routes towards the use of miRNAs as reliable biomarkers for cancer.

Absent MicroRNAs in Different Tissues of Patients with Acquired Cardiomyopathy

MicroRNAs (miRNAs) can be found in a wide range of tissues and body fluids, and their specific signatures can be used to determine diseases or predict clinical courses. The miRNA profiles in biological samples (tissue, serum, peripheral blood mononuclear cells or other body fluids) differ significantly even in the same patient and therefore have their own specificity for the presented condition. Complex profiles of deregulated miRNAs are of high interest, whereas the importance of non-expressed miRNAs was ignored. Since miRNAs regulate gene expression rather negatively, absent miRNAs could indicate genes with unaltered expression that therefore are normally expressed in specific compartments or under specific disease situations. For the first time, non-detectable miRNAs in different tissues and body fluids from patients with different diseases (cardiomyopathies, Alzheimer’s disease, bladder cancer, and ocular cancer) were analyzed and compared in this study. miRNA expression data were generated by microarray or TaqMan PCR-based platforms. Lists of absent miRNAs of primarily cardiac patients (myocardium, blood cells, and serum) were clustered and analyzed for potentially involved pathways using two prediction platforms, i.e., miRNA enrichment analysis and annotation tool (miEAA) and DIANA miRPath. Extensive search in biomedical publication databases for the relevance of non-expressed miRNAs in predicted pathways revealed no evidence for their involvement in heart-related pathways as indicated by software tools, confirming proposed approach.

Chronic pistachio intake modulates circulating microRNAs related to glucose metabolism and insulin resistance in prediabetic subjects

PURPOSE

To assess the effects of a pistachio-enriched diet on the profile of circulating microRNAs (miRNAs) related to glucose metabolism and insulin resistance (IR).

METHODS

Randomized crossover clinical trial in 49 subjects with prediabetes was performed. Subjects consumed a pistachio-supplemented diet (PD, 50 % carbohydrates, 33 % fat, including 57 g/day of pistachios) and an isocaloric control diet (CD, 55 % carbohydrates and 30 % fat) for 4 months each, separated by a 2-week washout period. The plasma profile of a set of seven predefined miRNAs related to glucose and insulin metabolism was analyzed by quantitative RT-PCR.

RESULTS

After the PD period, subjects have shown significant lower circulating levels of miR-192 and miR-375 compared to CD period, whereas miR-21 nonsignificantly increased after PD compared with CD (47 vs. 2 %, P = 0.092). Interestingly, changes in circulating miR-192 and miR-375 were positively correlated with plasma glucose, insulin and HOMA-IR.

CONCLUSION

Chronic pistachio consumption positively modulates the expression of some miRNA previously implicated on insulin sensitivity.

CRP and SAA1 Haplotypes Are Associated with Both C-Reactive Protein and Serum Amyloid A Levels: Role of Suppression Effects

To test the statistical association of the CRP and SAA1 locus variants with their corresponding circulating levels and metabolic and inflammatory biomarker levels by using mediation analysis, a sample population of 599 Taiwanese subjects was enrolled and five CRP and four SAA1 variants were genotyped. Correlation analysis revealed that C-reactive protein (CRP) and serum amyloid A (SAA) levels were significantly associated with multiple metabolic phenotypes and inflammatory marker levels. Our data further revealed a significant association of CRP and SAA1 variants with both CRP and SAA levels. Mediation analysis revealed that SAA levels suppressed the association between SAA1 genotypes/haplotypes and CRP levels and that CRP levels suppressed the association between CRP haplotypes and SAA levels. In conclusion, genetic variants at the CRP and SAA1 loci independently affect both CRP and SAA levels, and their respective circulating levels act as suppressors. These results provided further evidence of the role of the suppression effect in biological science and may partially explain the missing heritability in genetic association studies.

Locked nucleic acid inhibits miR-92a-3p in human colorectal cancer, induces apoptosis and inhibits cell proliferation

MicroRNAs (miRNAs) are a type of small noncoding RNAs that have a vital role in basic biological processes such as cellular growth, division and apoptosis. A change in the expression of miRNAs can induce many diseases. Recently, the role of miRNA in some of the cancers as a tumor suppressor and oncogene has been recognized. Several studies have proved that miR-92a-3p acts as an oncogene in colorectal cancer (CRC). We studied CRC by inhibiting miR-92a-3p in SW48 cells (human colorectal cancer cell line) that were transfected with locked nucleic acid (LNA). At different times, the expression level of miR-92a-3p, cell vitality, apoptosis and necrosis were studied by qRT-PCR, MTT, Annexin-V and propidiumiodide. Our results showed that the expression of miR-92a-3p and proliferation of SW48 cells were decreased, and also a high percentage of SW48 cells were exposed to apoptosis and necrosis (P⩽0.005). Our study showed that the inhibition of miR-92a-3p with LNA inhibited cell proliferation and induced apoptosis and necrosis in CRC.

Identification of cardiomyopathy associated circulating miRNA biomarkers in patients with muscular dystrophy using a complementary cardiovascular magnetic resonance and plasma profiling approach

BACKGROUND

Duchenne and Becker muscular dystrophy (DMD and BMD) are X-chromosomal recessive neuromuscular disorders that are caused by mutations in the dystrophin gene and characterized by cardiac involvement. Circulating microRNAs (miRNAs) have been proposed as diagnostic biomarkers for various cardiovascular diseases. However, circulating miRNAs reflecting the presence and/or disease severity of cardiac involvement in DMD/BMD patients have not been described so far.

METHODS

Sixty-three male patients with known MD and 26 age-matched healthy male controls were prospectively enrolled. All MD patients and controls underwent comprehensive cardiovascular magnetic resonance (CMR) studies as well as venous blood sampling on the same day.

RESULTS

An impaired left ventricular (LV) systolic function (defined as LV-EF <55 %) was detected in 29 (46 %) and presence of late gadolinium enhancement (LGE) indicative of myocardial fibrosis in 48 (76 %) MD patients with an exclusively non-ischemic pattern. Whereas no significant differences were observed for the 27 selected circulating miRNAs in MD patients with abnormal CMR findings (comprising structural and/or functional impairments) compared to those with completely normal CMR studies, a significant up-regulation of three miRNAs was observed in LGE-positive MD patients compared to LGE-negative ones: miR-222 (1.8-fold, p = 0.035), miR-26a (2.1-fold, p = 0.03) and miR-378a-5p (2.4-fold, p = 0.026). A signature of these three miRNAs (miR-26a, miR-222 and miR-378a-5p) resulted in an area under the curve (AUC) value of 0.74 for the diagnosis of LGE-positive MD patients. In a multivariable model, three independent predictors for LGE presence were identified comprising not only clinical and laboratory markers (LV-EF: OR 0.47, 95 % CI 0.24-0.89, p = 0.021 and elevated hs-Trop: OR 2559, 95 % CI 2.97-22.04*10(5), p = 0.023) but also the circulating miR-222 (OR 938, 95 % CI 938.46, 3.56-24.73*10(4), p = 0.016).

CONCLUSIONS

Up-regulation of circulating miRNAs miR-222, miR-26a and miR-378a-5p indicates the presence of myocardial scars in MD patients. Plasma miR-222 appears to be a promising novel biomarker reflecting structural - but not functional - cardiac alterations in MD patients.