The diagnostic values of circulating miRNAs for hypertension and bioinformatics analysis

Impact of microRNAs on cardiovascular diseases and aging

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality for both men and women among all ethnicities worldwide. Although significant improvements in the management of CVD occurred in the 20th century, non-invasive, universal, early diagnostic biomarkers and newer therapeutic drugs are needed for clinical treatment by physicians. MicroRNAs (miRNAs) are a class of endogenous, non-coding, single-stranded, small RNA molecules that are critically controlled by all human biological processes. Moreover, dysregulated miRNA expression is directly involved in various CVDs, including stable coronary artery disease and acute coronary syndrome. Several miRNAs that are enriched in the plasma of CVD patients have potential as clinical biomarkers, and overexpression or inhibition of specific miRNAs has novel therapeutic significance in the management of CVD. Aging is a multifactorial physiological process that gradually deteriorates tissue and organ function and is considered a non-modifiable major risk factor for CVDs. Recently, several studies established that various miRNAs essentially regulate aging and aging-related disease processes. This narrative review briefly discusses the recently updated molecular involvement of miRNAs in CVDs, their possible diagnostic, prognostic, and therapeutic value, and their relationship to the aging process.

DAE-CFR: detecting microRNA-disease associations using deep autoencoder and combined feature representation

BACKGROUND

MicroRNA (miRNA) has been shown to play a key role in the occurrence and progression of diseases, making uncovering miRNA-disease associations vital for disease prevention and therapy. However, traditional laboratory methods for detecting these associations are slow, strenuous, expensive, and uncertain. Although numerous advanced algorithms have emerged, it is still a challenge to develop more effective methods to explore underlying miRNA-disease associations.

RESULTS

In the study, we designed a novel approach on the basis of deep autoencoder and combined feature representation (DAE-CFR) to predict possible miRNA-disease associations. We began by creating integrated similarity matrices of miRNAs and diseases, performing a logistic function transformation, balancing positive and negative samples with k-means clustering, and constructing training samples. Then, deep autoencoder was used to extract low-dimensional feature from two kinds of feature representations for miRNAs and diseases, namely, original association information-based and similarity information-based. Next, we combined the resulting features for each miRNA-disease pair and used a logistic regression (LR) classifier to infer all unknown miRNA-disease interactions. Under five and tenfold cross-validation (CV) frameworks, DAE-CFR not only outperformed six popular algorithms and nine classifiers, but also demonstrated superior performance on an additional dataset. Furthermore, case studies on three diseases (myocardial infarction, hypertension and stroke) confirmed the validity of DAE-CFR in practice.

CONCLUSIONS

DAE-CFR achieved outstanding performance in predicting miRNA-disease associations and can provide evidence to inform biological experiments and clinical therapy.

Circulating microRNA Biomarkers of Thiazide Response in Hypertension

BACKGROUND

Thiazide diuretics are the second most frequently prescribed class of antihypertensives, but up to 50% of patients with hypertension have minimal antihypertensive response to thiazides. We explored circulating microRNAs (miRNAs) in search of predictive biomarkers of thiazide response.

METHODS AND RESULTS

We profiled 754 miRNAs in baseline plasma samples of 36 hypertensive European American adults treated with hydrochlorothiazide, categorized into responders (n=18) and nonresponders (n=18) on the basis of diastolic blood pressure response to hydrochlorothiazide. miRNAs with ≥2.5-fold differential expression between responders and nonresponders were considered for validation in 3 cohorts (n=50 each): hydrochlorothiazide-treated European Americans, chlorthalidone-treated European Americans, and hydrochlorothiazide-treated Black individuals. Different blood pressure phenotypes including categorical (responder versus nonresponder) and continuous diastolic blood pressure and systolic blood pressure were tested for association with the candidate miRNA expression using multivariate regression analyses adjusting for age, sex, and baseline blood pressure. After quality control, 74 miRNAs were available for screening, 19 of which were considered for validation. In the validation cohort, miR-193b-3p and 30d-5p showed significant associations with continuous SBP or diastolic blood pressure response or both, to hydrochlorothiazide in European Americans at Benjamini-Hochberg adjusted P<0.05. In the combined analysis of validation cohorts, let-7g (odds ratio, 0.6 [95% CI, 0.4-0.8]), miR-142-3p (odds ratio, 1.1 [95% CI, 1.0, 1.2]), and miR-423-5p (odds ratio, 0.7 [95% CI, 0.5-0.9]) associated with categorical diastolic blood pressure response at Benjamini-Hochberg adjusted P<0.05. Predicted target genes of the 5 miRNAs were mapped to key hypertension pathways: lysine degradation, fatty acid biosynthesis, and metabolism.

CONCLUSIONS

The above identified circulating miRNAs may have a potential for clinical use as biomarkers for thiazide diuretic selection in hypertension.

REGISTRATION

URL: ClinicalTrials.gov. Unique identifiers: NCT00246519, NCT01203852, NCT00005520.

Integrated analysis of the lncRNA-associated competing endogenous RNA network in salt sensitivity of blood pressure

Accumulating evidence showed that competing endogenous RNA (ceRNA) mechanism plays a pivotal role in salt sensitivity of blood pressure (SSBP). We constructed a ceRNA network based on SSBP-related differently expressed lncRNAs (2), mRNAs (73) and miRNAs (18). Bioinformatic analyses were utilized to analyze network and found network genes participate in biological pathways related to SSBP pathogenesis such as regulation of nitric oxide biosynthetic process (GO:0045,428) and cellular response to cytokine stimulus (GO:0071,345). Fourteen candidate ceRNA pathways were selected from network to perform qRT-PCR validation and found nine RNAs (KCNQ1OT1, SLC8A1-AS1, IL1B, BCL2L11, KCNJ15, CX3CR1, KLF2, hsa-miR-362-5p and hsa-miR-423-5p) differently expressed between salt-sensitive (SS) and salt-resistant (SR) groups (P < 0.05). Four ceRNA pathways were further validated by luciferase reporter assay and found KCNQ1OT1→hsa-miR-362-5p/hsa-miR-423-5p→IL1B pathways may influence the pathogenic mechanism of SS. Our findings suggested the ceRNA pathway and network may affect SS occurrence mainly through endothelial dysfunction and inflammatory activation.

MiR-122-5p as a potential regulator of pulmonary vascular wall cell in idiopathic pulmonary arterial hypertension

MicroRNAs (miRNAs) are versatile regulators of pulmonary arterial remodeling in idiopathic pulmonary arterial hypertension (IPAH). We herein aimed to characterize miRNAs in peripheral blood mononuclear cell (PBMC) and plasma exosomes, and investigate specific miRNA expression in pulmonary artery cells and lung tissues in IPAH. A co-dysregulated miRNA was identified from the miRNA expression profiles of PBMC and plasma exosomes in IPAH. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed the potential function of differentially expressed miRNAs. Real-time quantitative reverse transcription polymerase chain reaction was used to validate the expression of specific miRNAs in hypoxia-induced pulmonary microvascular endothelial cells (PMECs), pulmonary artery smooth muscle cells (PASMCs), pericyte cells (PCs), and lung tissues of patients with IPAH and rats. Finally, the miRNA-mRNA mechanisms of miR-122-5p were predicted. MiR-122-5p was the only co-upregulated miRNA in PBMC and plasma exosomes in patients with IPAH. Functional analysis of differentially expressed miRNAs revealed associations with the GO terms "transcription, DNA-templated," "cytoplasm," and "metal ion binding" in both PBMC and plasma exosomes, KEGG pathway MAPK signaling in PBMC, and KEGG-pathway human papillomavirus infection in plasma exosomes. Hypoxic PMECs and PCs, lung tissue of patients with IPAH, and rats showed increased expression of miR-122-5p, but hypoxic PASMCs showed decreased expression. And miR-122-5p mimics and inhibitor affected cell proliferation. Finally, miR-122-5p was found to potentially target DLAT (in lung tissue) and RIMS1 (in PMECs) in IPAH. According to the dual-luciferase assay, miR-122-5p bound to DLAT or RIMS1. In studies, DLAT imbalance was associated with cell proliferation and migration, RIMS1 is differentially expressed in cancer and correlated with cancer prognosis. Our findings suggest that the miR-122-5p is involved in various biological functions in the adjacent vascular wall cells in IPAH.

The key roles of non-coding RNAs in the pathophysiology of hypertension

Hypertension is a multifactorial condition in which several genetic and environmental elements contribute. Recent investigations have revealed contribution of non-coding region of the transcriptome in this trait. CDKN2B-AS1, AK098656, MEG3, H19, PAXIP1-AS1, TUG1, GAS5, CASC2 and CPS1-IT are among long non-coding RNAs participating in the pathophysiology of hypertension. Several miRNAs have also been found to be implicated in this disorder. miR-296, miR-637, miR-296, miR-637, hsa-miR-361-5p, miR-122-5p, miR-199a-3p, miR-208a-3p, miR-423-5p, miR-223-5p and miR-140-5p are among dysregulated miRNAs in this condition whose application as diagnostic biomarkers for hypertension has been evaluated. Finally, hsa-circ-0005870, hsa_circ_0037911 and hsa_circ_0014243 are examples of dysregulated circular RNAs in hypertensive patients. In the current review, we describe the role of these non-coding RNAs in the pathophysiology of hypertension.

Relationship Between Circulating MicroRNAs and Left Ventricular Hypertrophy in Hypertensive Patients

Objective

Left ventricular hypertrophy (LVH) is a common complication of hypertension and microRNAs (miRNAs) are considered to play an important role in cardiac hypertrophy development. This study evaluated the relationship between circulating miRNAs and LVH in hypertensive patients.

Methods

Two cohorts [exploratory (n = 42) and validation (n = 297)] of hypertensive patients were evaluated by clinical, laboratory and echocardiography analysis. The serum expression of 754 miRNAs in the exploratory cohort and 6 miRNAs in the validation cohort was evaluated by the TaqMan OpenArray^® system and quantitative polymerase chain reaction, respectively.

Results

Among the 754 analyzed miRNAs, ten miRNAs (miR-30a-5p, miR-let7c, miR-92a, miR-451, miR-145-5p, miR-185, miR-338, miR-296, miR-375, and miR-10) had differential expression between individuals with and without LVH in the exploratory cohort. Results of multivariable regression analysis adjusted for confounding variables showed that three miRNAs (miR-145-5p, miR-451, and miR-let7c) were independently associated with LVH and left ventricular mass index in the validation cohort. Functional enrichment analysis demonstrated that these three miRNAs can regulate various genes and pathways related to cardiac remodeling. Furthermore, in vitro experiments using cardiac myocytes demonstrated that miR-145-5p mimic transfection up-regulated the expression of brain and atrial natriuretic peptide genes, which are markers of cardiac hypertrophy, while anti-miR-145-5p transfection abrogated the expression of these genes in response to norepinephrine stimulus.

Conclusions

Our data demonstrated that circulating levels of several miRNAs, in particular miR-145-5p, miR-451, and let7c, were associated with LVH in hypertensive patients, indicating that these miRNAS may be potential circulating biomarkers or involved in hypertension-induced LV remodeling.

Comparison of Data Normalization Strategies for Array-Based MicroRNA Profiling Experiments and Identification and Validation of Circulating MicroRNAs as Endogenous Controls in Hypertension

Introduction: MicroRNAs are small noncoding RNAs with potential regulatory roles in hypertension and drug response. The presence of many of these RNAs in biofluids has spurred investigation into their role as possible biomarkers for use in precision approaches to healthcare. One of the major challenges in clinical translation of circulating miRNA biomarkers is the limited replication across studies due to lack of standards for data normalization techniques for array-based approaches and a lack of consensus on an endogenous control normalizer for qPCR-based candidate miRNA profiling studies.

Methods: We conducted genome-wide profiling of 754 miRNAs in baseline plasma of 36 European American individuals with uncomplicated hypertension selected from the PEAR clinical trial, who had been untreated for hypertension for at least one month prior to sample collection. After appropriate quality control with amplification score and missingness filters, we tested different normalization strategies such as normalization with global mean of imputed and unimputed data, mean of restricted set of miRNAs, quantile normalization, and endogenous control miRNA normalization to identify the method that best reduces the technical/experimental variability in the data. We identified best endogenous control candidates with expression pattern closest to the mean miRNA expression in the sample, as well as by assessing their stability using a combination of NormFinder, geNorm, Best Keeper and Delta Ct algorithms under the Reffinder software. The suitability of the four best endogenous controls was validated in 50 hypertensive African Americans from the same trial with reverse-transcription–qPCR and by evaluating their stability ranking in that cohort.

Results: Among the compared normalization strategies, quantile normalization and global mean normalization performed better than others in terms of reducing the standard deviation of miRNAs across samples in the array-based data. Among the four strongest candidate miRNAs from our selection process (miR-223-3p, 19b, 106a, and 126-5p), miR-223-3p and miR-126-5p were consistently expressed with the best stability ranking in the validation cohort. Furthermore, the combination of miR-223-3p and 126-5p showed better stability ranking when compared to single miRNAs.

Conclusion: We identified quantile normalization followed by global mean normalization to be the best methods in reducing the variance in the data. We identified the combination of miR-223-3p and 126-5p as potential endogenous control in studies of hypertension.

LncRNA FENDRR Servers as a Possible Marker of Essential Hypertension and Regulates Human Umbilical Vein Endothelial Cells Dysfunction via miR-423-5p/Nox4 Axis

Purpose

Essential hypertension (EH) is an intricate non-communicable infirmity and lncRNAs are validated as essential mediators in EH. The study aimed to propose the expression pattern of FENDRR and miR-423-5p, substantiate the potential mechanism of FENDRR/miR-423-5p/Nox4 axis in EH.

Patients and Methods

The expression of FENDRR and miR-423-5p was evaluated by qRT-PCR and the clinical significance was explored by the ROC curve. Pearson correlation indicated the relationship between FENDRR and miR-423-5p. The function of FENDRR and miR-423-5p on HUVECs was clarified by CCK-8 assay, Transwell assay, and flow cytometry. Western blot was used to assess the relative protein expression of Nox4.

Results

FENDRR was highly expressed and miR-423-5p was lowly expressed in EH patients and a negative correlation between them was determined. FENDRR might serve as a predictive diagnosis in differentiating EH patients. Knockdown of FENDRR or overexpression of miR-423-5p showed expansionary effects in cell proliferation, cell migration, and inhibiting cell apoptosis. Meanwhile, miR-423-5p was determined as a target of FENDRR and mediated the function of FENDRR on HUVECs. Moreover, Nox4 is a down-streaming target gene of miR-423-5p. The protein expression of Nox4 was regulated by the alternation of miR-423-5p expression.

Conclusion

FENDRR played an energetic role in EH and contributed to HUVECs dysfunction by restricting cell proliferation, suppressing cell migration, and accelerating cell apoptosis by manipulating the miR-423-5p/Nox4 axis.

Thromboangiitis obliterans plasma-derived exosomal miR-223-5p inhibits cell viability and promotes cell apoptosis of human vascular smooth muscle cells by targeting VCAM1

Background: Exosomes-encapsulated microRNAs (miRNAs) have been established to be implicated in the pathogenesis of different diseases. Nevertheless, circulating exosomal miRNAs of thromboangiitis obliterans (TAO) remains poorly understood. This study aimed to explore the effects of exosomal miRNAs associated with TAO on human vascular smooth muscle cells (HVSMCs).Methods: The exosomes were isolated from the plasma of TAO patients and normal controls and then were sent for small RNA sequencing. Differentially expressed miRNAs (DE-miRNAs) were identified by bioinformatics analysis and were confirmed by RT-qPCR. After that, PKH67 staining was used to label exosomes and co-cultured with HVSMCs. Cell viability and apoptosis were, respectively, tested by CCK-8 assay and flow cytometry. Finally, dual-luciferase reporter assay was used to confirm the downstream targets of miR-223-5p.Results: A total of 39 DE-miRNAs were identified between TAO patients and normal controls, of which, miR-223-5p was one of the most significantly up-regulated miRNAs. TAO plasma-derived exosomes or miR-223-5p mimics inhibited cell viability of HVSMCs and promoted cell apoptosis. The pro-apoptotic effect of TAO plasma-derived exosomes was alleviated by miR-223-5p inhibitor. Additionally, the expressions of VCAM1 and IGF1R were down-regulated by exosomes and miR-223-5p mimics, and were abrogated by miR-223-5p inhibitor. Dual-luciferase report showed that VCAM1 was the target of miR-223-5p.Conclusions: Our findings imply that circulating exosomal miR-223-5p may play an essential role in the pathogenesis of TAO, and provide a basis for miR-6515-5p/VCAM1 as novel therapeutic targets and pathways for TAO treatment.

Molecular Characterization and Elucidation of Pathways to Identify Novel Therapeutic Targets in Pulmonary Arterial Hypertension

Background: Pulmonary arterial hypertension (PAH) is a life-threatening chronic cardiopulmonary disease. However, there are limited studies reflecting the available biomarkers from separate gene expression profiles in PAH. This study explored two microarray datasets by an integrative analysis to estimate the molecular signatures in PAH. Methods: Two microarray datasets (GSE53408 and GSE113439) were exploited to compare lung tissue transcriptomes of patients and controls with PAH and to estimate differentially expressed genes (DEGs). According to common DEGs of datasets, gene and protein overrepresentation analyses, protein-protein interactions (PPIs), DEG-transcription factor (TF) interactions, DEG-microRNA (miRNA) interactions, drug-target protein interactions, and protein subcellular localizations were conducted in this study. Results: We obtained 38 common DEGs for these two datasets. Integration of the genome transcriptome datasets with biomolecular interactions revealed hub genes (HSP90AA1, ANGPT2, HSPD1, HSPH1, TTN, SPP1, SMC4, EEA1, and DKC1), TFs (FOXC1, FOXL1, GATA2, YY1, and SRF), and miRNAs (hsa-mir-17-5p, hsa-mir-26b-5p, hsa-mir-122-5p, hsa-mir-20a-5p, and hsa-mir-106b-5p). Protein-drug interactions indicated that two compounds, namely, nedocromil and SNX-5422, affect the identification of PAH candidate biomolecules. Moreover, the molecular signatures were mostly localized in the extracellular and nuclear areas. Conclusions: In conclusion, several lung tissue-derived molecular signatures, highlighted in this study, might serve as novel evidence for elucidating the essential mechanisms of PAH. The potential drugs associated with these molecules could thus contribute to the development of diagnostic and therapeutic strategies to ameliorate PAH.

Exosomal microRNAs in the development of essential hypertension and its potential as biomarkers

MicroRNAs (miRNAs) are small regulatory molecules that are involved in posttranscriptional modifications. These noncoding RNAs are usually ferried by extracellular carriers such as exosomes or other protein and lipid carriers inside a range of body fluids including plasma and urine. Due to their ability to withstand harsh external conditions, exosomal miRNAs possess enormous potential as noninvasive disease biomarkers for, notably hypertension, whereby exosomal miRNAs have been implicated in its pathophysiological processes. More importantly, alterations in the microenvironment as a result of disease progression can induce active and selective loading of miRNAs into exosomes. In this paper, we first review the mechanisms of miRNA loading into exosomes, followed by the roles of exosomal miRNAs in the development of hypertension, and the potentials of exosomal miRNAs as biomarkers in comparison with other free circulating miRNAs. Finally, challenges and future research surrounding exosomal miRNAs will also be discussed. This review will aid in the understanding of noninvasive biomarkers for the early diagnosis of hypertension and for probing therapeutic efficacy.

MiR-223-3p in Cardiovascular Diseases: A Biomarker and Potential Therapeutic Target

Cardiovascular diseases, involving vasculopathy, cardiac dysfunction, or circulatory disturbance, have become the major cause of death globally and brought heavy social burdens. The complexity and diversity of the pathogenic factors add difficulties to diagnosis and treatment, as well as lead to poor prognosis of these diseases. MicroRNAs are short non-coding RNAs to modulate gene expression through directly binding to the 3′-untranslated regions of mRNAs of target genes and thereby to downregulate the protein levels post-transcriptionally. The multiple regulatory effects of microRNAs have been investigated extensively in cardiovascular diseases. MiR-223-3p, expressed in multiple cells such as macrophages, platelets, hepatocytes, and cardiomyocytes to modulate their cellular activities through targeting a variety of genes, is involved in the pathological progression of many cardiovascular diseases. It participates in regulation of several crucial signaling pathways such as phosphatidylinositol 3-kinase/protein kinase B, insulin-like growth factor 1, nuclear factor kappa B, mitogen-activated protein kinase, NOD-like receptor family pyrin domain containing 3 inflammasome, and ribosomal protein S6 kinase B1/hypoxia inducible factor 1 α pathways to affect cell proliferation, migration, apoptosis, hypertrophy, and polarization, as well as electrophysiology, resulting in dysfunction of cardiovascular system. Here, in this review, we will discuss the role of miR-223-3p in cardiovascular diseases, involving its verified targets, influenced signaling pathways, and regulation of cell function. In addition, the potential of miR-223-3p as therapeutic target and biomarker for diagnosis and prediction of cardiovascular diseases will be further discussed, providing clues for clinicians.

Roles of MicroRNA-122 in Cardiovascular Fibrosis and Related Diseases

Fibrotic diseases cause annually more than 800,000 deaths worldwide, where of the majority accounts for cardiovascular fibrosis, which is characterized by endothelial dysfunction, myocardial stiffening and reduced dispensability. MicroRNAs (miRs), small noncoding RNAs, play critical roles in cardiovascular dysfunction and related disorders. Intriguingly, there is a critical link among miR-122, cardiovascular fibrosis, sirtuin 6 (SIRT6) and angiotensin-converting enzyme 2 (ACE2), which was recently identified as a coreceptor for SARS-CoV2 and a negative regulator of the rennin-angiotensin system. MiR-122 overexpression appears to exacerbate the angiotensin II-mediated loss of autophagy and increased inflammation, apoptosis, extracellular matrix deposition, cardiovascular fibrosis and dysfunction by modulating the SIRT6-Elabela-ACE2, LGR4-β-catenin, TGFβ-CTGF and PTEN-PI3K-Akt signaling pathways. More importantly, the inhibition of miR-122 has proautophagic, antioxidant, anti-inflammatory, anti-apoptotic and antifibrotic effects. Clinical and experimental studies clearly demonstrate that miR-122 functions as a crucial hallmark of fibrogenesis, cardiovascular injury and dysfunction. Additionally, the miR-122 level is related to the severity of hypertension, atherosclerosis, atrial fibrillation, acute myocardial infarction and heart failure, and miR-122 expression is a risk factor for these diseases. The miR-122 level has emerged as an early-warning biomarker cardiovascular fibrosis, and targeting miR-122 is a novel therapeutic approach against progression of cardiovascular dysfunction. Therefore, an increased understanding of the cardiovascular roles of miR-122 will help the development of effective interventions. This review summarizes the biogenesis of miR-122; regulatory effects and underlying mechanisms of miR-122 on cardiovascular fibrosis and related diseases; and its function as a potential specific biomarker for cardiovascular dysfunction.

Circulating microRNA-133a in Patients With Arterial Hypertension, Hypertensive Heart Disease, and Left Ventricular Diastolic Dysfunction

Aim: The aim of the work was to study the circulating microRNA-133a levels in blood plasma of patients with arterial hypertension (AH), hypertensive heart disease (HHD), and left ventricular (LV) diastolic dysfunction (DD). Materials and Methods: A total of 48 patients with grade 2-3 AH and HHD at the age of 52.23 ± 7.26 (23 patients had LV DD [main group] and 25 patients had normal LV diastolic function [comparison group]) and 21 practically healthy individuals of comparable gender and age were examined. Diagnosis of AH and HHD was carried out according to the 2018 ESC/ESH recommendations. LV DD was determined according to the 2016 ASE/EACVI recommendations. Plasma microRNA-133a level was obtained by polymerase chain reaction using the CFX96 Touch System (BioRad), ≪TaqMan microRNA Assay≫ and ≪TaqMan® Universal PCR Master Mix≫ reagent kits (Thermo Fisher Scientific, USA). Results: We have found that in patients from the main and comparison groups plasma microRNA-133a levels were significantly lower than in practically healthy individuals (0.094 [0.067, 0.147]) and (0.182 [0.102, 0.301]) vs. (0.382 [0.198,0.474]), p = 0.002 and p = 0.04, respectively. In all this among patients with AH, HHD, and LV DD, plasma microRNA-133a levels were significantly lower than in patients with AH, HHD, and normal diastolic function (p = 0.03). In the main and comparison groups there was a statistically significant negative relationship between plasma microRNA-133a level and left ventricular mass index (LVMI) (R = -0.40, p = 0.003 and R = -0.35, p = 0.04, respectively). Conclusions: The findings suggest the significant role of decreased microRNA-133a levels in blood plasma of patients with AH in the pathogenesis and development of both HHD and LV DD.

Circulating miR-3135b and miR-107 are potential biomarkers for severe hypertension

Hypertension is a disease relating to multiple etiological factors. However, the molecular mechanisms of severe hypertension remain unclear. Whole-body circulatory dysregulation has been found to contribute to hypertension, documenting that circulating molecules are focused as pathological molecules implicated in hypertension. Circulating microRNAs (miRNAs) have been identified as important molecular biomarkers for hypertension. We screened and analyzed miRNAs differentially expressed in plasma in patients with severe hypertension and healthy controls using microarray profiling (six patients and six healthy controls for screening) and RT-qPCR (33 patients and 33 healthy controls for validation). We identified that miR-3135b and miR-107 are the differentially expressed miRNAs between severe hypertension and healthy controls, and the target genes independently regulated by the two miRNAs are remarkably different. MiR-3135b and miR-107 are potential biomarkers for severe hypertension.

MicroRNA 3113-5p is a novel marker for early cardiac ischemia/reperfusion injury

BACKGROUND

Ischemia/reperfusion (I/R) injury of heart is one of the major causes of acute cardiac injury, which may result in worsening or even loss of heart function. With novel microRNAs being evolutionarily discovered, numbers of them remained functionally unknown. We aimed to discover novel microRNAs with therapeutic or diagnostic potential in the setting of early cardiac I/R injury.

METHODS

Cardiac electrical activity, biochemical detection and histopathology analysis were performed to reveal early changes of cardiac I/R injury. A microRNA array was performed to screen differential microRNAs in the mouse model of cardiac I/R injury. The differentially expressed microRNAs were validated in cardiac tissues and in serum samples.

RESULTS

The abnormality in electrocardiogram and increases in serum cTnI levels suggested the successful establishment of cardiac I/R injury in mice. A total of 1882 microRNAs were identified, of which 11 were significantly down-regulated and 41 were significantly up-regulated at 3 h post reperfusion. microRNA 223-3p and microRNA 3113-5p were among the mostly altered microRNAs and were validated to be up-regulated within the early hours of I/R injury in heart tissues. In the circulating system, cTnI, a sensitive marker of cardiac injury, or microRNA 223-3p only increased within the first 6 h post I/R injury. However, microRNA 3113-5p stably increased in the serum, keeping an increase of 2.5-fold throughout the 24 h. In the human serum samples, microRNA 3113-5p was detected to be significantly upregulated as soon as 3 h after I/R stimuli and kept significantly higher levels within the 48 h.

CONCLUSION

This is the first study that reported the functional roles of microRNA 3113-5p in cardiovascular system. Our data suggested that cardiac microRNA 3113-5p might be a useful target for therapeutic purposes and circulating microRNA 3113-5p might serve as a stable marker for early diagnosis of cardiac I/R injury.

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.

Epigenetic modification: a regulatory mechanism in essential hypertension

Essential hypertension (EH) is a multifactorial disease of the cardiovascular system that is influenced by the interplay of genetic, epigenetic, and environmental factors. The molecular dynamics underlying EH etiopathogenesis is unknown; however, earlier studies have revealed EH-associated genetic variants. Nevertheless, this finding alone is not sufficient to explain the variability in blood pressure, suggesting that other risk factors are involved, such as epigenetic modifications. Therefore, this review highlights the potential contribution of well-defined epigenetic mechanisms in EH, specifically, DNA methylation, post-translational histone modifications, and microRNAs. We further emphasize global and gene-specific DNA methylation as one of the most well-studied hallmarks among all epigenetic modifications in EH. In addition, post-translational histone modifications, such as methylation, acetylation, and phosphorylation, are described as important epigenetic markers associated with EH. Finally, we discuss microRNAs that affect blood pressure by regulating master genes such as those implicated in the renin-angiotensin-aldosterone system. These epigenetic modifications, which appear to contribute to various cardiovascular diseases, including EH, may be a promising research area for the development of novel future strategies for EH prevention and therapeutics.