CVD-associated non-coding RNA, ANRIL, modulates expression of atherogenic pathways in VSMC

The mechanisms of Chr.9p21.3 risk locus in coronary artery disease: where are we today?

Despite the advancements and release of new therapeutics in the past few years, cardiovascular diseases (CVDs) have remained the number one cause of death worldwide. Genetic variation of a 9p21.3 genomic locus has been identified as the most significant and robust genetic CVD risk marker on the population level, with the strongest association with coronary artery disease (CAD) and other diseases, including diabetes and cancer. Several mechanisms of 9p21.3 in CVDs have been proposed, but their effects on CVDs have remained elusive. Moreover, most of the single nucleotide polymorphisms (SNPs) associated with CAD are located on a sequence of a long noncoding RNA (lncRNA) called ANRIL. ANRIL has several linear and circular splicing isoforms, which seem to have different effects and implications for CVDs. The mechanisms of the 9p21.3 locus and the interplay of its coding and noncoding transcripts in different diseases require further research. Circular RNAs have generally raised interest due to their beneficial features as biomarkers and therapeutic molecules. Here, we review the literature of 9p21.3 from its identification in 2007 and draw the current knowledge on its function, implications in CVDs, and therapeutic potential.

Non-coding RNAs to treat vascular smooth muscle cell dysfunction

Vascular smooth muscle cell (vSMC) dysfunction is a critical contributor to cardiovascular diseases, including atherosclerosis, restenosis and vein graft failure. Recent advances have unveiled a fascinating range of non-coding RNAs (ncRNAs) that play a pivotal role in regulating vSMC function. This review aims to provide an in-depth analysis of the mechanisms underlying vSMC dysfunction and the therapeutic potential of various ncRNAs in mitigating this dysfunction, either preventing or reversing it. We explore the intricate interplay of microRNAs, long-non-coding RNAs and circular RNAs, shedding light on their roles in regulating key signalling pathways associated with vSMC dysfunction. We also discuss the prospects and challenges associated with developing ncRNA-based therapies for this prevalent type of cardiovascular pathology. LINKED ARTICLES: This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

Single-cell sequencing analysis confirms the association of ANRIL with the increased smooth muscle cell proliferation and migration gene signatures in pulmonary artery hypertension in silico

PURPOSE

Smooth muscle cell (SMC) dysregulation is part of the pathological basis of pulmonary artery hypertension (PAH). We aimed to explore the heterogeneity of SMCs in PAH.

METHODS

The profile GSE210248 was obtained from NCBI Gene Expression Omnibus, containing the scRNA-seq data of pulmonary arteries (PA) from three patients with PAH and three healthy donors. After quality control, normalization, and dimension reduction, cell clustering analysis was performed. Differential expression analysis and functional enrichment analysis were carried out successively in smooth muscle cells (SMCs). The enrichment scores of cell cycle and cell migration gene sets in SMCs were calculated. Then, the Spearman correlation coefficients between antisense non-coding RNA in the INK4 locus (ANRIL) expression and two gene sets were computed.

RESULTS

Eight cell clusters were identified in PA from samples. The proportion of SMCs was increased in PAH samples. SMCs were divided into five subclusters with diverse biological functions. Muscle contraction-related SMC1 was decreased, while extracellular matrix organization-related SMC2, immune and inflammatory response-related SMC4 and SMC5 were increased in PAH samples compared with healthy donors. The enrichment scores of cell cycle and cell migration gene sets in SMCs were higher in PAH samples than in donors. ANRIL was down-regulated significantly in PAH samples and was negatively related to the scores of two gene sets.

CONCLUSION

SMCs exhibited significant heterogeneity in PAH. The altered abilities of SMC proliferation and migration in PAH were associated with ANRIL expression.

Progress and trends in myocardial infarction-related long non-coding RNAs: a bibliometric analysis

Background

Myocardial infarction (MI), a critical condition, substantially affects patient outcomes and mortality rates. Long non-coding RNAs (lncRNAs) play a critical role in the onset and progression of MI. This study aimed to explore the related research on MI-related lncRNAs from a bibliometric perspective, providing new clues and directions for researchers in the field.

Methods

A comprehensive search was conducted on 7 August 2023, using the Web of Science Core Collection (WoSCC) database to compile a dataset of all English-language scientific journals. The search gathered all relevant publications from January 2000 to August 2023 that pertain to MI-related lncRNAs. Data on countries, institutions, journals, authors, and keywords were collected, sorted, statistically analyzed, and visualized using CiteSpace 6.2.R4, VOSviewer 1.6.19, an online bibliometric analysis platform (http://bibliometric.com), and the bibliometric package in R-Studio 4.3.1. Articles were screened by two independent reviewers.

Results

Between January 2000 and August 2023, a total of 1,452 papers were published in the research field of MI-related lncRNAs. The year with the most publications was 2020, accounting for 256 papers. The publication volume displayed an exponential growth trend, fitting the equation y = 2.0215e0.2786x, R^2 = 0.97. In this domain, China leads in both the number of published papers (N = 1,034) and total citations, followed by the United States, Germany, Iran, and Italy. The most productive institution is Harbin Medical University (N = 144). The European Review for Medical and Pharmacological Sciences had the highest number of publications (N = 46), while Circulation Research had the most citations (TC = 4,537), indicating its irreplaceable standing in this field. Research mainly focuses on the cardiovascular system, cellular biology, physiology, etc. The most productive author is Zhang Y. Apart from "Myocardial Infarction" and "LncRNA," the most frequent keywords include "expression," "atherosclerosis," and "apoptosis." Cluster analysis suggests current research themes concentrate on cardiovascular diseases and gene expression, cardiac ischemia/reperfusion injury and protection, expression and proliferation, atherosclerosis and inflammatory response, among others. Keyword bursts indicate recent hot topics as targeting, autophagy, etc.

Conclusion

This bibliometric analysis reveals that research on MI-related lncRNAs has rapidly expanded between January 2000 and August 2023, primarily led by China and the United States. Our study highlights the significant biological roles of lncRNAs in the pathogenesis and progression of MI, including their involvement in gene expression regulation, atherosclerosis development, and apoptosis. These findings underscore the potential of lncRNAs as therapeutic targets and biomarkers for MI. Additionally, our study provides insights into the features and quality of related publications, as well as the future directions in this research field. There is a long road ahead, highlighting the urgent need for enhanced global academic exchange.

Beyond the silence: A comprehensive exploration of long non-coding RNAs as genetic whispers and their essential regulatory functions in cardiovascular disorders

Long non-coding RNAs (lncRNAs) are RNA molecules that regulate gene expression at several levels, including transcriptional, post-transcriptional, and translational. They have a length of more than 200 nucleotides and cannot code. Many human diseases have been linked to aberrant lncRNA expression, highlighting the need for a better knowledge of disease etiology to drive improvements in diagnostic, prognostic, and therapeutic methods. Cardiovascular diseases (CVDs) are one of the leading causes of death worldwide. LncRNAs play an essential role in the complex process of heart formation, and their abnormalities have been associated with several CVDs. This Review article looks at the roles and relationships of long non-coding RNAs (lncRNAs) in a wide range of CVDs, such as heart failure, myocardial infarction, atherosclerosis, and cardiac hypertrophy. In addition, the review delves into the possible uses of lncRNAs in diagnostics, prognosis, and clinical treatments of cardiovascular diseases. Additionally, it considers the field's future prospects while examining how lncRNAs might be altered and its clinical applications.

ANRIL: A Long Noncoding RNA in Age-related Diseases

The intensification of the aging population is often accompanied by an increase in agerelated diseases, which impair the quality of life of the elderly. The characteristic feature of aging is progressive physiological decline, which is the largest cause of human pathology and death worldwide. However, natural aging interacts in exceptionally complex ways within and between organs, but its underlying mechanisms are still poorly understood. Long non-coding RNA (lncRNA) is a type of noncoding RNA that exceeds 200 nucleotides in length and does not possess protein-coding ability. It plays a crucial role in the occurrence and development of diseases. ANRIL, also known as CDKN2B-AS1, is an antisense ncRNA located at the INK4 site. It can play a crucial role in agerelated disease progression by regulating single nucleotide polymorphism, histone modifications, or post-transcriptional modifications (such as RNA stability and microRNA), such as cardiovascular disease, diabetes, tumor, arthritis, and osteoporosis. Therefore, a deeper understanding of the molecular mechanisms of lncRNA ANRIL in age-related diseases will help provide new diagnostic and therapeutic targets for clinical practice.

Long non-coding RNAs: The hidden players in diabetes mellitus-related complications

BACKGROUND AND AIM

Long non-coding RNAs (lncRNAs) have been recognized as important regulators of gene expression in various human diseases. Diabetes mellitus (DM) is a long-term metabolic disorder associated with serious macro and microvascular complications. This review discusses the potential lncRNAs involved in DM-related complications such as dysfunction of pancreatic beta islets, nephropathy, retinopathy, cardiomyopathy, and peripheral neuropathy.

METHODS

An extensive literature search was conducted in the Scopus database to find information from reputed biomedical articles published on lncRNAs and diabetic complications from 2014 to 2023. All review articles were collected and statistically analyzed, and the findings were summarized. In addition, the potential lncRNAs involved in DM-related complications, molecular mechanisms, and gene targets were discussed in detail.

RESULTS

The lncRNAs ANRIL, E33, MALAT1, PVT1, Erbb4-IR, Gm4419, Gm5524, MIAT, MEG3, KNCQ1OT1, Uc.48+, BC168687, HOTAIR, and NONRATT021972 were upregulated in several diabetic complications. However, βlinc1, H19, PLUTO, MEG3, GAS5, uc.322, HOTAIR, MIAT, TUG1, CASC2, CYP4B1-PS1-001, SOX2OT, and Crnde were downregulated. Remarkably, lncRNAs MALAT1, ANRIL, MIAT, MEG3, H19, and HOTAIR were overlapping in more than one diabetic complication and were considered potential lncRNAs.

CONCLUSION

Several lncRNAs are identified as regulators of DM-related complications. The expression of lncRNAs is up or downregulated depending on the disease context, target genes, and regulatory partners. However, most lncRNAs target oxidative stress, inflammation, apoptosis, fibrosis, and angiogenesis pathways to mediate their protective/pathogenic mechanism of action and contribute to DM-related complications.

Plumbing mysterious RNAs in "dark genome" for the conquest of human diseases

Next-generation sequencing has revealed that less than 2% of transcribed genes are translated into proteins, with a large portion transcribed into noncoding RNAs (ncRNAs). Among these, long noncoding RNAs (lncRNAs) represent the largest group and are pervasively transcribed throughout the genome. Dysfunctions in lncRNAs have been found in various diseases, highlighting their potential as therapeutic, diagnostic, and prognostic targets. However, challenges, such as unknown molecular mechanisms and nonspecific immune responses, and issues of drug specificity and delivery present obstacles in translating lncRNAs into clinical applications. In this review, we summarize recent publications that have explored lncRNA functions in human diseases. We also discuss challenges and future directions for developing lncRNA treatments, aiming to bridge the gap between functional studies and clinical potential and inspire further exploration in the field.

Diabetic cardiomyopathy: The role of microRNAs and long non-coding RNAs

Diabetes mellitus (DM) is on the rise, necessitating the development of novel therapeutic and preventive strategies to mitigate the disease's debilitating effects. Diabetic cardiomyopathy (DCMP) is among the leading causes of morbidity and mortality in diabetic patients globally. DCMP manifests as cardiomyocyte hypertrophy, apoptosis, and myocardial interstitial fibrosis before progressing to heart failure. Evidence suggests that non-coding RNAs, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), regulate diabetic cardiomyopathy-related processes such as insulin resistance, cardiomyocyte apoptosis and inflammation, emphasizing their heart-protective effects. This paper reviewed the literature data from animal and human studies on the non-trivial roles of miRNAs and lncRNAs in the context of DCMP in diabetes and demonstrated their future potential in DCMP treatment in diabetic patients.

Non-coding RNAs in stroke pathology, diagnostics, and therapeutics

Ischemic stroke is a leading cause of death and disability worldwide. Methods to alleviate functional deficits after ischemic stroke focus on restoration of cerebral blood flow to the affected area. However, pharmacological or surgical methods such as thrombolysis and thrombectomy have a narrow effective window. Harnessing and manipulating neurochemical processes of recovery may provide an alternative to these methods. Recently, non-coding RNA (ncRNA) have been increasingly investigated for their contributions to the pathology of diseases and potential for diagnostic and therapeutic applications. Here we will review several ncRNA - H19, MALAT1, ANRIL, NEAT1, pseudogenes, small nucleolar RNA, piwi-interacting RNA and circular RNA - and their involvement in stroke pathology. We also examine these ncRNA as potential diagnostic biomarkers, particularly in circulating blood, and as targets for therapeutic interventions. An important aspect of this is a discussion of potential methods of treatment delivery to allow for targeting of interventions past the blood-brain barrier, including lipid nanoparticles, polymer nanoparticles, and viral and non-viral vectors. Overall, several long non-coding RNA (lncRNA) discussed here have strong implications for the development of pathology and functional recovery after ischemic stroke. LncRNAs H19 and ANRIL show potential as diagnostic biomarkers, while H19 and MALAT1 may prove to be effective therapeutics for both minimising damage as well as promoting recovery. Other ncRNA have also been implicated in ischemic stroke but are currently too poorly understood to make inferences for diagnosis or treatment. Whilst the field of ncRNAs is relatively new, significant work has already highlighted that ncRNAs represent a promising novel investigative tool for understanding stroke pathology, could be used as diagnostic biomarkers, and as targets for therapeutic interventions.

Long non-coding RNAs at the crossroad of vascular smooth muscle cell phenotypic modulation in atherosclerosis and neointimal formation

Despite extraordinary advances in the comprehension of the pathophysiology of atherosclerosis and the employment of very effective treatments, cardiovascular diseases are still a major cause of mortality and represent a large share of health expenditure worldwide. Atherosclerosis is a disease affecting the medium and large arteries, which consists of a progressive accumulation of fatty substances, cellular waste products and fibrous elements, which culminates in the buildup of a plaque obstructing the blood flow. Endothelial dysfunction represents an early pathological event, favoring immune cells recruitment and triggering local inflammation. The release of inflammatory cytokines and other signaling molecules stimulates phenotypic modifications in the underlying vascular smooth muscle cells, which, in physiological conditions, are responsible for the maintenance of vessels architecture while regulating vascular tone. Vascular smooth muscle cells are highly plastic and may respond to disease stimuli by de-differentiating and losing their contractility, while increasing their synthetic, proliferative, and migratory capacity. This phenotypic switching is considered a pathological hallmark of atherogenesis and is ruled by the activation of selective gene programs. The advent of genomics and the improvement of sequencing technologies deepened our knowledge of the complex gene expression regulatory networks mediated by non-coding RNAs, and favored the rise of innovative therapeutic approaches targeting the non-coding transcriptome. In the context of atherosclerosis, long non-coding RNAs have received increasing attention as potential translational targets, due to their contribution to the molecular dynamics modulating the expression of vascular smooth muscle cells contractile/synthetic gene programs. In this review, we will focus on the most well-characterized long non-coding RNAs contributing to atherosclerosis by controlling expression of the contractile apparatus and genes activated in perturbed vascular smooth muscle cells.

Asian-specific 3'UTR variant in CDKN2B associated with risk of pituitary adenoma

BACKGROUND

Previous genomewide association studies (GWASs), single nucleotide polymorphisms (SNPs) on cyclin-dependent kinase inhibitor 2 A (CDKN2A), cyclin-dependent kinase inhibitor 2B (CDKN2B), and cyclin-dependent kinase inhibitor 2B antisense RNA1 (CDKN2B-AS1) were reported as risk loci for glioma, a subgroup of the brain tumor. To further characterize this association with the risk of brain tumors in a Korean population, we performed a fine-mapping association study of CDKN2A, CDKN2B, and CDKN2B-AS1.

METHODS AND RESULTS

A total of 17 SNPs were selected and genotyped in 1,439 subjects which were comprised of 959 patients (pituitary adenoma 335; glioma 324; meningioma 300) and 480 population controls (PCs). We discovered that a 3'untranslated region (3'UTR) variant, rs181031884 of CDKN2B (Asian-specific variant), had significant association with the risk of pituitary adenoma (PA) (Odds ratio = 0.58, P = 0.00003). Also, rs181031884 appeared as an independent causal variant among the significant variants in CDKN2A and CDKN2B, and showed dose-dependent effects on PA.

CONCLUSIONS

Although further studies are needed to verify the impact of this variant on PA susceptibility, our results may help to understand CDKN2B polymorphism and the risk of PA.

LncRNA SENCR overexpression attenuated the proliferation, migration and phenotypic switching of vascular smooth muscle cells in aortic dissection via the miR-206/myocardin axis

BACKGROUND AND AIMS

Smooth muscle and endothelial cell-enriched migration/differentiation-associated lncRNA (SENCR) has been reported to be associated with some cardiovascular diseases; however, its function and exact molecular mechanism in aortic dissection (AD) remain undefined. Thus, we investigated the effects of SENCR on AD and its potential mechanisms.

METHODS AND RESULTS

SENCR expression in aortic media specimens from AD patients was detected by quantitative real-time PCR (qPCR). The roles of SENCR in vascular smooth muscle cell (VMSC) proliferation and migration as well as in the regulation of contractile phenotype genes were studied using CCK-8, wound healing, Transwell, qPCR and Western blot assays. Dual-luciferase reporter assays were performed to identify the regulatory correlation between SENCR, miR-206 and myocardin. Furthermore, mouse AD models were constructed with ApoE^-/- mice, and the effect of upregulated SENCR on phenotypic switching in the AD model was detected using hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) assays. SENCR overexpression inhibited VSMC proliferation, migration and synthetic phenotype-related gene expression; decreased miR-206 expression; increased myocardin expression; and suppressed rupture of the aortic media in mice. SENCR knockdown had the opposite effects. Our results further suggested that miR-206 upregulation could reverse the inhibitory roles of SENCR upregulation and that myocardin upregulation could restore the function of SENCR upregulation in VSMCs. Dual-luciferase reporter assays confirmed that SENCR regulated miR-206, which directly targeted myocardin in VSMCs.

CONCLUSION

SENCR overexpression suppressed VMSC proliferation and migration, maintained the contractile phenotype and suppressed aortic dilatation via the miR-206/myocardin axis.

Integrated bioinformatics analysis for the identification of hub genes and signaling pathways related to circANRIL

Background

Antisense noncoding RNA in the INK4 locus (ANRIL) is located on human chromosome 9p21, and modulation of ANRIL expression mediates susceptibility to some important human disease, including atherosclerosis (AS) and tumors, by affecting the cell cycle circANRIL and linear ANRIL are isoforms of ANRIL. However, it remains unclear whether these isoforms have distinct functions. In our research, we constructed a circANRIL overexpression plasmid, transfected it into HEK-293T cell line, and explored potential core genes and signaling pathways related to the important differential mechanisms between the circANRIL-overexpressing cell line and control cells through bioinformatics analysis.

Methods

Stable circANRIL-overexpressing (circANRIL-OE) HEK-293T cells and control cells were generated by infection with the circANRIL-OE lentiviral vector or a negative control vector, and successful transfection was confirmed by conventional flurescence microscopy and quantitative real-time PCR (qRT-PCR). Next, differentially expressed genes (DEGs) between circANRIL-OE cells and control cells were detected. Subsequently, Gene Ontology (GO) biological process (BP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to explore the principal functions of the significant DEGs. A protein-protein interaction (PPI) network and competing endogenous RNA (ceRNA) network were constructed in Cytoscape to determine circularRNA (circRNA)- microRNA(miRNA)-messenger RNA (mRNA) interactions and hub genes, and qRT-PCR was used to verify changes in the expression of these identified target genes.

Results

The successful construction of circANRIL-OE cells was confirmed by plasmid sequencing, visualization with fluorescence microscopy and qRT-PCR. A total of 1745 DEGs between the circANRIL-OE group and control were identified, GO BP analysis showed that these genes were mostly related to RNA biosynthesis and processing, regulation of transcription and signal transduction. The KEGG pathway analysis showed that the up regulated DEGs were mainly enriched in the MAPK signaling pathway. Five associated target genes were identified in the ceRNA network and biological function analyses. The mRNA levels of these five genes and ANRIL were detected by qRT-PCR, but only COL5A2 and WDR3 showed significantly different expression in circANRIL-OE cells.

The Role of ANRIL in Atherosclerosis

There is a huge number of noncoding RNA (ncRNA) transcripts in the cell with important roles in modulation of different mechanisms. ANRIL is a long ncRNA with 3.8 kb length that is transcribed in the opposite direction of the INK4/ARF locus in chromosome 9p21. It was shown that polymorphisms within this locus are associated with vascular disorders, notably coronary artery disease (CAD), which is considered as a risk factor for life-threatening events like myocardial infarction and stroke. ANRIL is subjected to a variety of splicing patterns producing multiple isoforms. Linear isoforms could be further transformed into circular ones by back-splicing. ANRIL regulates genes in atherogenic network in a positive or negative manner. This regulation is implemented both locally and remotely. While CAD is known as a proliferative disorder and cell proliferation plays a crucial role in the progression of atherosclerosis, the functions of ANRIL and CAD development are intertwined remarkably. This makes ANRIL a suitable target for diagnostic, prognostic, and even therapeutic aims. In this review, we tried to present a comprehensive appraisal on different aspects of ANRIL including its location, structure, isoforms, expression, and functions. In each step, the contribution of ANRIL to atherosclerosis is discussed.

Expression ratio of circular to linear ANRIL in hypertensive patients with coronary artery disease

Atherosclerotic lesions of the coronary arteries are still in charge of significant annual morbidity and mortality despite intense therapeutic advancements. Genome-born elements contribute substantially to the atherosclerosis process. ANRIL is one of the long non-coding RNAs with outstanding functions particularly regulation of genes involved in atherosclerosis development. In this study, we measured ANRIL expression (circular-, linear-, and circular/linear ratio) in hypertensive patients with coronary artery disease (CAD) compared with peers without CAD. Among hypertensive patients who were candidates of angiography, 25 subjects with CAD and the equal number without CAD were considered as the case and control groups, respectively. Different categories of data were recorded through a predefined questionnaire. Before angiography, blood samples were obtained. After RNA extraction and cDNA synthesis, quantitative PCR was performed using specific primers for circular and linear ANRIL. Age and gender were not different between the groups. Most of the parameters of the lipid profile besides creatinine and blood urea nitrogen were remarkably worse in the case group. Circular ANRIL was significantly lower in the case group while linear counterparts were significantly higher in this group. Circular/linear ratio was also significantly lower in the case group. To overcome growing devastating trend of CAD, scrutinizing different factors involved in the initiation and development of atherosclerosis is a must. Atheroprotective role of circular ANRIL and atheroprogressive role of linear ANRIL were shown in our patients with hypertension.

Flow-Responsive Noncoding RNAs in the Vascular System: Basic Mechanisms for the Clinician

The vascular system is largely exposed to the effect of changing flow conditions. Vascular cells can sense flow and its changes. Flow sensing is of pivotal importance for vascular remodeling. In fact, it influences the development and progression of atherosclerosis, controls its location and has a major influx on the development of local complications. Despite its importance, the research community has traditionally paid scarce attention to studying the association between different flow conditions and vascular biology. More recently, a growing body of evidence has been accumulating, revealing that ncRNAs play a key role in the modulation of several biological processes linking flow-sensing to vascular pathophysiology. This review summarizes the most relevant evidence on ncRNAs that are directly or indirectly responsive to flow conditions to the benefit of the clinician, with a focus on the underpinning mechanisms and their potential application as disease biomarkers.

The Combined Regulation of Long Non-coding RNA and RNA-Binding Proteins in Atherosclerosis

Atherosclerosis is a complex disease closely related to the function of endothelial cells (ECs), monocytes/macrophages, and vascular smooth muscle cells (VSMCs). Despite a good understanding of the pathogenesis of atherosclerosis, the underlying molecular mechanisms are still only poorly understood. Therefore, atherosclerosis continues to be an important clinical issue worthy of further research. Recent evidence has shown that long non-coding RNAs (lncRNAs) and RNA-binding proteins (RBPs) can serve as important regulators of cellular function in atherosclerosis. Besides, several studies have shown that lncRNAs are partly dependent on the specific interaction with RBPs to exert their function. This review summarizes the important contributions of lncRNAs and RBPs in atherosclerosis and provides novel and comprehensible interaction models of lncRNAs and RBPs.

Role of Long Non-Coding RNAs in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a debilitating condition of the pulmonary circulatory system that occurs in patients of all ages and if untreated, eventually leads to right heart failure and death. Despite existing medical treatment options that improve survival and quality of life, the disease remains incurable. Thus, there is an urgent need to develop novel therapies to treat this disease. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play critical roles in pulmonary vascular remodeling and PAH. LncRNAs are implicated in pulmonary arterial endothelial dysfunction by modulating endothelial cell proliferation, angiogenesis, endothelial mesenchymal transition, and metabolism. LncRNAs are also involved in inducing different pulmonary arterial vascular smooth muscle cell phenotypes, such as cell proliferation, apoptosis, migration, regulation of the phenotypic switching, and cell cycle. LncRNAs are essential regulators of gene expression that affect various diseases at the chromatin, transcriptional, post-translational, and even post-translational levels. Here, we focus on the role of LncRNAs and their molecular mechanisms in the pathogenesis of PAH. We also discuss the current research challenge and potential biomarker and therapeutic potentials of lncRNAs in PAH.

LncRNA ANRIL Facilitates Vascular Smooth Muscle Cell Proliferation and Suppresses Apoptosis via Modulation of miR-7/FGF2 Pathway in Intracranial Aneurysms

BACKGROUND

Proliferation and apoptosis of vascular smooth muscle cells (VSMCs) are linked to intracranial aneurysm (IA) formation and progression. Long antisense noncoding RNA in the INK4 locus (ANRIL) has been reported to regulate VSMC functions in several cardiovascular diseases. However, little is known about how ANRIL influences VSMC proliferation and apoptosis during IA pathogenesis.

METHODS

The expression level of ANRIL in the plasma and arterial wall tissues of patients with IA was detected by real-time quantitative polymerase chain reaction. The functional role of ANRIL in the regulation of VSMC proliferation and apoptosis and its downstream regulatory mechanism were determined using Cell Counting Kit 8, immunofluorescence, terminal-deoxynucleotidyl transferase-mediated UTP nick end labeling, western blotting, luciferase reporter assay, and RNA immunoprecipitation assay.

RESULTS

ANRIL was downregulated in the plasma and arterial wall tissues of patients with IA, when compared with control groups. Overexpression of ANRIL significantly promoted VSMC proliferation and blocked cell apoptosis. Mechanistic studies demonstrated that ANRIL directly bound to microRNA-7 (miR-7) and that overexpression of miR-7 overturned the increased cell proliferation and decreased cell apoptosis, which was induced by ANRIL restoration. Besides, further study showed that ANRIL positively regulated fibroblast growth factor 2 (FGF2) expression via targeting miR-7.

CONCLUSIONS

These results suggested that ANRIL affects VSMC proliferation and apoptosis via regulation of the miR-7/FGF2 pathway in IA, which provided a potential novel strategy for the treatment of IA.

Implication of repeat insertion domains in the trans-activity of the long non-coding RNA ANRIL

Long non-coding RNAs have emerged as critical regulators of cell homeostasis by modulating gene expression at chromatin level for instance. Here, we report that the lncRNA ANRIL, associated with several pathologies, binds to thousands of loci dispersed throughout the mammalian genome sharing a 21-bp motif enriched in G/A residues. By combining ANRIL genomic occupancy with transcriptomic analysis, we established a list of 65 and 123 genes potentially directly activated and silenced by ANRIL in trans, respectively. We also found that Exon8 of ANRIL, mainly made of transposable elements, contributes to ANRIL genomic association and consequently to its trans-activity. Furthermore, we showed that Exon8 favors ANRIL's association with the FIRRE, TPD52L1 and IGFBP3 loci to modulate their expression through H3K27me3 deposition. We also investigated the mechanisms engaged by Exon8 to favor ANRIL's association with the genome. Our data refine ANRIL's trans-activity and highlight the functional importance of TEs on ANRIL's activity.

The Role of Long Non-coding RNAs in Sepsis-Induced Cardiac Dysfunction

Sepsis is a syndrome with life-threatening organ dysfunction induced by a dysregulated host response to infection. The heart is one of the most commonly involved organs during sepsis, and cardiac dysfunction, which is usually indicative of an extremely poor clinical outcome, is a leading cause of death in septic cases. Despite substantial improvements in the understanding of the mechanisms that contribute to the origin and responses to sepsis, the prognosis of sepsis-induced cardiac dysfunction (SICD) remains poor and its molecular pathophysiological changes are not well-characterized. The recently discovered group of mediators known as long non-coding RNAs (lncRNAs) have presented novel insights and opportunities to explore the mechanisms and development of SICD and may provide new targets for diagnosis and therapeutic strategies. LncRNAs are RNA transcripts of more than 200 nucleotides with limited or no protein-coding potential. Evidence has rapidly accumulated from numerous studies on how lncRNAs function in associated regulatory circuits during SICD. This review outlines the direct evidence of the effect of lncRNAs on SICD based on clinical trials and animal studies. Furthermore, potential functional lncRNAs in SICD that have been identified in sepsis studies are summarized with a proven biological function in research on other cardiovascular diseases.

Heart Enhancers: Development and Disease Control at a Distance

Bound by lineage-determining transcription factors and signaling effectors, enhancers play essential roles in controlling spatiotemporal gene expression profiles during development, homeostasis and disease. Recent synergistic advances in functional genomic technologies, combined with the developmental biology toolbox, have resulted in unprecedented genome-wide annotation of heart enhancers and their target genes. Starting with early studies of vertebrate heart enhancers and ending with state-of-the-art genome-wide enhancer discovery and testing, we will review how studying heart enhancers in metazoan species has helped inform our understanding of cardiac development and disease.

MicroRNAs and long non-coding RNAs in the pathophysiological processes of diabetic cardiomyopathy: emerging biomarkers and potential therapeutics

The epidemic of diabetes mellitus (DM) necessitates the development of novel therapeutic and preventative strategies to attenuate complications of this debilitating disease. Diabetic cardiomyopathy (DCM) is a frequent disorder affecting individuals diagnosed with DM characterized by left ventricular hypertrophy, diastolic and systolic dysfunction and myocardial fibrosis in the absence of other heart diseases. Progression of DCM is associated with impaired cardiac insulin metabolic signaling, increased oxidative stress, impaired mitochondrial and cardiomyocyte calcium metabolism, and inflammation. Various non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), as well as their target genes are implicated in the complex pathophysiology of DCM. It has been demonstrated that miRNAs and lncRNAs play an important role in maintaining homeostasis through regulation of multiple genes, thus they attract substantial scientific interest as biomarkers for diagnosis, prognosis and as a potential therapeutic strategy in DM complications. This article will review the different miRNAs and lncRNA studied in the context of DM, including type 1 and type 2 diabetes and the contribution of pathophysiological mechanisms including inflammatory response, oxidative stress, apoptosis, hypertrophy and fibrosis to the development of DCM .

Long noncoding RNA ANRIL as a novel biomarker in human cancer

The long noncoding RNA ANRIL, located in the human chromosome 9p21 region, has been reported to be involved in tumor progression. ANRIL regulates gene expression via recruiting PRC2 or titrating miRNA; it also participates in signaling pathways. Evidence has indicated that ANRIL is overexpressed in many cancer types and is capable of enhancing cell proliferation and cell cycle progression and inhibiting apoptosis and senescence. ANRIL has the potential to serve as a biomarker for diagnosis and prognosis in cancer. In this article we focus on recent advances in studies of the oncogenic role of ANRIL and its potential role in cancer medicine.

The long noncoding RNA PDK1-AS/miR-125b-5p/VEGFA axis modulates human dermal microvascular endothelial cell and human umbilical vein endothelial cell angiogenesis after thermal injury

Our previous study confirmed the critical role of miR-125b and vascular endothelial growth factor (VEGF) in burn wound repair., The present study was aimed to identify the role of long noncoding RNAs (lncRNAs) related to the function of miR-125b and VEGF in burn wound repair and the underlying mechanism. First, we found that lncRNA PDK1-AS and VEGFA expression was significantly increased in heat-denatured dermal tissue samples and in human dermal microvascular endothelial cells (HDMECs) and human umbilical vein endothelial cells (HUVECs) after thermal injury. PDK1-AS knockdown significantly inhibited cell viability, cumulative tube length, cell migratory ability, and cell invasion of thermally injured HDMECs and HUVECs. PDK1-AS knockdown decreased VEGFA protein levels in HDMECs and HUVECs. While overexpression of PDK1-AS showed the opposite effects. Online tools prediction and luciferase assay confirmed that miR-125b-5p targeted PDK1-AS and VEGFA 3'-untranslated region. miR-125b-5p inhibition significantly increased VEGFA protein levels and enhanced viability, cumulative tube length, migratory ability, and invasion of HUVECs and HDMECs. Furthermore, the effects of PDK1-AS knockdown on VEGFA protein levels in the two cell lines were partially reversed by miR-125b-5p inhibition. Finally, in the tissue samples, PDK1-AS and VEGFA expression was increased, while miR-125b-5p expression was decreased in heat-denatured dermal tissues; the expression of miR-125b-5p had a negative correlation with PDK1-AS and VEGFA, respectively, and PDK1-AS and VEGFA were positively correlated with each other in tissue samples. In conclusion, PDK1-AS relieves miR-125b-5p-induced inhibition on VEGFA by acting as a endogenous RNA, therefore modulating HDMEC and HUVEC angiogenesis after thermal injury.

New findings in the roles of Cyclin-dependent Kinase inhibitors 2B Antisense RNA 1 (CDKN2B-AS1) rs1333049 G/C and rs4977574 A/G variants on the risk to coronary heart disease

The relationship between Cyclin-Dependent Kinase Inhibitors 2B Antisense RNA 1 (CDKN2B-AS1) variants rs1333049 G/C and rs4977574 A/G and the risk of coronary heart disease is unclear. We conducted an update analysis incorporating odds ratios and 95% confidence intervals to assess the correlation. Furthermore, we used in silico analysis to investigate the genes and proteins that interact with CDKN2B. Fifty case-control studies with a sample size of 35,915 cases and 48,873 controls were involved. We revealed that the rs1333049 C allele could increase the risk of coronary heart disease in the overall analysis (allele comparison, OR = 1.13, 95%CI = 1.05–1.21, P = 0.001; homozygous contrast, OR = 1.29, 95%CI = 1.11–1.49, P = 0.001; dominant comparison, OR = 1.14, 95%CI = 1.03–1.27, P = 0.011; recessive comparison, OR = 1.21, 95%CI = 1.10–1.34, P < 0.001). In subgroup analysis, positive correlations were detected in studies involving West and East Asians and in population-based control studies. The rs4977574 G allele was also a risk factor for coronary heart disease (allelic comparison, P = 0.001; heterozygous comparison, P = 0.003; homozygous comparison, P < 0.001; dominant comparison, P = 0.001). These results indicate correlation of CDKN2B-AS1 rs1333049 G/C and rs4977574 A/G variants may be correlated with the risk of coronary heart disease.

Abbreviations CDK: Cyclin Dependent Kinase; CCND: G1/S-specific cyclin-D; CDKN: Cyclin Dependent Kinase Inhibitor; GWAS: Genome-wide association study; CDKN2B-AS1: Cyclin-Dependent Kinase Inhibitors 2B Antisense RNA 1; CHD: Coronary heart disease; MAF: minor allele frequencies; HWE: Hardy-Weinberg equilibrium of controls; CI: confidence interval; COL8A2: Collagen type VIII alpha 2 chain; HB: Hospital-based; ORs: odds ratios; ITGA11: Integrin subunit alpha 11; LTBP: Latent transforming factor beta binding protein; PB: Population-based; IBC: Itmat Broad Care; NA: Not applicable; PCR-RFLP: polymerase chain reaction-restriction fragment length polymorphism; MI: Myocardial Infarction; SNP: single nucleotide polymorphism; SMAD: Mothers against decapentaplegic homolog; RT-PCR: Real-time polymerase chain reaction; UK: United Kingdom

Histone Deacetylase SIRT1, Smooth Muscle Cell Function, and Vascular Diseases

Vascular smooth muscle cells (VSMCs), located in the media of artery, play key roles in maintaining the normal vascular physiological functions. Abnormality in VSMCs is implicated in vascular diseases (VDs), including atherosclerosis, abdominal aortic aneurysm (AAA), aortic dissection, and hypertension by regulating the process of inflammation, phenotypic switching, and extracellular matrix degradation. Sirtuins (SIRTs), a family of proteins containing seven members (from SIRT1 to SIRT7) in mammals, function as NAD⁺-dependent histone deacetylases and ADP-ribosyltransferases. In recent decades, great attention has been paid to the cardiovascular protective effects of SIRTs, especially SIRT1, suggesting a new therapeutic target for the treatment of VDs. In this review, we introduce the basic functions of SIRT1 against VSMC senescence, and summarize the contribution of SIRT1 derived from VSMCs in VDs. Finally, the potential new strategies based on SIRT1 activation have also been discussed with an emphasis on SIRT1 activators and calorie restriction to improve the prognosis of VDs.

The Long Non-coding RNAs: Paramount Regulators of the NLRP3 Inflammasome

The NOD LRR pyrin domain containing protein 3 (NLRP3) inflammasome is a cytosolic multi-proteins conglomerate with intrinsic ATPase activity. Their predominant presence in the immune cells emphasizes its significant role in immune response. The downstream effector proteins IL-1β and IL-18 are responsible for the biological functions of the NLRP3 inflammasome upon encountering the alarmins and microbial ligands. Although the NLRP3 inflammasome is essential for host defense during infections, uncontrolled activation and overproduction of IL-1β and IL-18 increase the risk of developing autoimmune and metabolic disorders. Emerging evidences suggest the action of lncRNAs in regulating the activity of NLRP3 inflammasome in various disease conditions. The long non-coding RNA (lncRNA) is an emerging field of study and evidence on their regulatory role in various diseases is grabbing attention. Recent studies emphasize the functions of lncRNAs in the fine control of the NLRP3 inflammasome at nuclear and cytoplasmic levels by interfering in chromatin architecture, gene transcription and translation. Recently, lncRNAs are also found to control the activity of various regulators of NLRP3 inflammasome. Understanding the precise role of lncRNA in controlling the activity of NLRP3 inflammasome helps us to design targeted therapies for multiple inflammatory diseases. The present review is a novel attempt to consolidate the substantial role of lncRNAs in the regulation of the NLRP3 inflammasome. A deeper insight on the NLRP3 inflammasome regulation by lncRNAs will help in developing targeted and beneficial therapeutics in the future.

Molecular Genetics and Functional Analysis Implicate CDKN2BAS1-CDKN2B Involvement in POAG Pathogenesis

The genes in the 9p21 locus (CDKN2B-AS1 & CDKN2B) are widely associated with Primary open-angle glaucoma (POAG). However, the functional importance of this locus in POAG pathogenesis is still unexplored. This study investigated the role of CDKN2BAS1-CDKN2B axis in POAG. We observed significant association of CDKN2B-AS1 SNP rs4977756 with POAG and its endophenotypic traits (vertical cup-disc ratio (p = 0.033) and central corneal thickness (p = 0.008)) by screening African American POAG cases (n = 1567) and controls (n = 1600). A luciferase reporter assay in Human embryonic kidney 293T (HEK293T) cells revealed that the region surrounding rs4977756 likely serves as a transcriptional repressor. siRNA-mediated knockdown of CDKN2B-AS1 in HEK293T cells and trabecular meshwork (TM) cells resulted in significantly increased expression of CDKN2B, which was also observed in human POAG ocular tissues. Pathway focused qRT-PCR gene expression analysis showed increased cellular senescence, TGFβ signaling and ECM deposition in TM cells after CDKN2B-AS1 suppression. In conclusion, we report that CDKN2B-AS1 may act as a regulator, and it could function by modulating the expression of CDKN2B. In addition, increase in CDKN2B levels due to CDKN2B-AS1 suppression may result in the senescence of trabecular meshwork cells leading to POAG pathogenesis.

Non-coding RNAs in cardiovascular cell biology and atherosclerosis

Atherosclerosis underlies the predominant number of cardiovascular diseases and remains a leading cause of morbidity and mortality worldwide. The development, progression and formation of clinically relevant atherosclerotic plaques involves the interaction of distinct and over-lapping mechanisms which dictate the roles and actions of multiple resident and recruited cell types including endothelial cells, vascular smooth muscle cells, and monocyte/macrophages. The discovery of non-coding RNAs (ncRNAs) including microRNAs, long non-coding RNAs, and circular RNAs, and their identification as key mechanistic regulators of mRNA and protein expression has piqued interest in their potential contribution to atherosclerosis. Accruing evidence has revealed ncRNAs regulate pivotal cellular and molecular processes during all stages of atherosclerosis including cell invasion, growth, and survival; cellular uptake and efflux of lipids, expression and release of pro- and anti-inflammatory intermediaries, and proteolytic balance. The expression profile of ncRNAs within atherosclerotic lesions and the circulation have been determined with the aim of identifying individual or clusters of ncRNAs which may be viable therapeutic targets alongside deployment as biomarkers of atherosclerotic plaque progression. Consequently, numerous in vivo studies have been convened to determine the effects of moderating the function or expression of select ncRNAs in well-characterized animal models of atherosclerosis. Together, clinicopathological findings and studies in animal models have elucidated the multifaceted and frequently divergent effects ncRNAs impose both directly and indirectly on the formation and progression of atherosclerosis. From these findings' potential novel therapeutic targets and strategies have been discovered which may pave the way for further translational studies and possibly taken forward for clinical application.

Silencing of circular RNA ANRIL attenuates oxygen-glucose deprivation and reoxygenation-induced injury in human brain microvascular endothelial cells by sponging miR-622

BACKGROUND

Circular RNA (circRNA) is highly expressed in the brain tissue, but its molecular mechanism in cerebral ischemia-reperfusion remains unclear. Here, we explored the role and underlying mechanisms of circRNA antisense non-coding RNA in the INK4 locus (circ_ANRIL) in oxygen-glucose deprivation and reoxygenation (OGD/R)-induced cell injury.

RESULTS

The expression of circ_ANRIL in OGD/R-induced human brain microvascular endothelial cells (HBMECs) was significantly up-regulated, while that of miR-622 was significantly down-regulated. Overexpression of circ_ANRIL significantly inhibited the proliferation of OGD/R-induced HBMECs and aggravated OGD/R-induced cell apoptosis. Moreover, circ_ANRIL overexpression further increased the secretion of interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in OGD/R-treated HBMECs. The results of bioinformatics analysis and luciferase reporter assay indicated that circ_ANRIL served as an miR-622 sponge to negatively regulate the expression of miR-622 in OGD/R-treated HBMECs. Additionally, circ_ANRIL silencing exerted anti-apoptotic and anti-inflammatory effects by positively regulating the expression of miR-622. Furthermore, inhibition of OGD/R-induced activation of the nuclear factor (NF)-κB pathway by circ_ANRIL silencing was significantly reversed by treatment with miR-622 inhibitor.

CONCLUSIONS

Knockdown of circ_ANRIL improved OGD/R-induced cell damage, apoptosis, and inflammatory responses by inhibiting the NF-κB pathway through sponging miR-622.

The protective effects of long non-coding RNA-ANCR on arterial calcification

INTRODUCTION

Arterial calcification is a major factor for cardiovascular events and is characterized by vascular smooth muscle cells (VSMCs) transformed into osteoblast-like cells. Long non-coding RNAs (lncRNA) were recognized as important regulators of diverse biological processes. Previous studies have demonstrated that lncRNAs could regulate the proliferation and apoptosis of VSMCs. LncRNA-ANCR (Anti-differentiation ncRNA) is an essential mediator governing the differentiation of human osteoblast. However, it is unclear whether ANCR could regulate the osteoblastic differentiation of VSMCs. In this study, we determined the effect of ANCR on VSMCs differentiation and arterial calcification.

MATERIALS AND METHODS

Both cellular and mouse model of arterial calcification were, respectively, established to investigate the role of ANCR in the mechanism of arterial calcification. ANCR overexpressing lentivirus were used to investigate the effects of ANCR on the expression of bone proteins and autophagy-related molecules.

RESULTS

ANCR could inhibit β-glycerophosphate (β-GP)-induced VSMCs osteoblastic differentiation and mineralization due to decreased expressions of Runt-related transcription factor 2, bone morphogenetic protein-2, and formation of mineralized nodule, and attenuate high calcitriol-induced mice model of arterial calcification. Furthermore, ANCR could significantly increase LC3 and autophagy protein 5 expression in β-GP-stimulated VSMCs, and the effect could be inhibited by 3-methyladenine, a pharmacological inhibitor of autophagy.

CONCLUSION

ANCR may inhibit the osteoblastic differentiation of VSMCs and attenuate mice arterial calcification through activating autophagy.

circANRIL reduces vascular endothelial injury, oxidative stress and inflammation in rats with coronary atherosclerosis

Effects of circular antisense non-coding RNA in the INK4 locus (circANRIL) on vascular endothelial injury, oxidative stress and inflammation in rats with coronary atherosclerosis were studied by establishing a rat model of coronary atherosclerosis in which circANRIL was differentially expressed. A total of 40 healthy Sprague Dawley (SD) rats were randomly divided into research group (n=32) and control group (n=8). In research group, a rat model of coronary atherosclerosis was established without special treatment. The blood calcium (Ca²⁺) and lipid levels in the two groups were compared. After cell transfection, the rats were divided into blank group (untransfected), negative group (transfected with blank vector), circANRIL group (transfected with circANRIL overexpression plasmid) and circANRIL inhibitor group (transfected with circANRIL silencer). Then the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in each group were compared. Western blotting was adopted to detect the expressions of phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK), p38MAPK and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Finally, p-p38MAPK/GAPDH, p38MAPK/GAPDH and p-p38MAPK/p38MAPK were calculated. There were significant differences in the levels of serum Ca²⁺ and lipid between control group and research group (P<0.05). Besides, differences in LDH, SOD, MDA, TNF-α and IL-6 in the supernatant in each group were statistically significant (P<0.05 or P<0.01). Moreover, there were statistically significant differences in the gray values of p-p38MAPK/GAPDH and p38MAPK/GAPDH and their ratio p-p38MAPK/p38MAPK in each group (P<0.05 or P<0.01). Inhibiting the expression of circANRIL in coronary heart disease cases can reduce vascular endothelial injury, oxidative stress and inflammation.

Prioritization of causal genes for coronary artery disease based on cumulative evidence from experimental and in silico studies

Genome-wide association studies have led to a significant progress in identification of genomic loci affecting coronary artery disease (CAD) risk. However, revealing the causal genes responsible for the observed associations is challenging. In the present study, we aimed to prioritize CAD-relevant genes based on cumulative evidence from the published studies and our own study of colocalization between eQTLs and loci associated with CAD using SMR/HEIDI approach. Prior knowledge of candidate genes was extracted from both experimental and in silico studies, employing different prioritization algorithms. Our review systematized information for a total of 51 CAD-associated loci. We pinpointed 37 genes in 36 loci. For 27 genes we infer they are causal for CAD, and for 10 further genes we judge them most likely causal. Colocalization analysis showed that for 18 out of these loci, association with CAD can be explained by changes in gene expression in one or more CAD-relevant tissues. Furthermore, for 8 out of 36 loci, existing evidence suggested additional CAD-associated genes. For the remaining 15 loci, we concluded that evidence for gene prioritization remains inconsistent, insufficient, or absent. Our results provide deeper insights into the genetic etiology of CAD and demonstrate knowledge gaps where further research is warranted.

The Long Non-Coding RNA Landscape of Atherosclerotic Plaques

Currently, cardiovascular diseases continue to be the leading cause of death worldwide; therefore, atherosclerosis remains one of the most crucial public health problems. This chronic and complex disease is considered to be a result of aberrant lipid homeostasis and inflammation of the inner wall of arteries that leads to plaque development. In recent years, a specific class of non-coding RNAs that are characterised by transcript lengths longer than 200 nucleotides, called long non-coding RNAs (lncRNAs), has emerged. Moreover, a growing body of evidence indicates that deregulation of lncRNA expression may contribute to the development of many diseases. Despite continuous efforts in deciphering the molecular basis of atherosclerotic plaque (AP) formation, many aspects of this process remain elusive. Therefore, continuing efforts in this area should remain the highest priority in the coming years. Establishment of a standardised experimental pipeline and validation of lncRNAs as possible relevant biomarkers for cardiovascular disease would enable the translation of gathered findings into clinical practice.

Clinical Utility of the Inflammatory Factors Combined With Lipid Markers in the Diagnostic and Prognostic Assessment of Ischemic Stroke: Based on Logistic Regression Models

BACKGROUND

In this study, we developed novel logistic regression models for the diagnostic and prognostic assessment of ischemic stroke.

METHODS

A total of 288 ischemic stroke patients and 300 controls admitted to The First Affiliated Hospital of Soochow University were included in the testing group. Two validation groups from The Affiliated Kunshan Hospital of Jiangsu University and The Second Affiliated Hospital of Soochow University were included to assess our novel assessment models.

RESULTS

Results from the testing group indicated that the diagnostic assessment model for ischemic stroke prediction was: Logit(P) = 437.116 - 87.329 (Hypertension) - 89.700 (Smoking history) - 87.427 (Family history of ischemic stroke) - .090 (high-density lipoprotein cholesterol [HDL-C]) - 1.984 (low-density lipoprotein cholesterol [LDL-C]) - 17.005 (Lp(a)) - 15.486 (Apo A/Apo B), and the final prognostic assessment model of ischemic stroke was: Logit(P) = 458.437-92.343 (Hypertension) - 89.763 (Smoking history) + .251 (NLR) - .088 (HDL-C) - 1.994 (LDL-C) - 2.883 (hs-CRP) - .058 (IL-6) - 6.356 (TNF-α) - 16.485 (Lp(a)) - 17.658 (Apo A/Apo B). In the validation groups, our novel diagnostic assessment model showed good identification (with 87.5% sensitivity and 84.2% specificity in The Affiliated Kunshan Hospital of Jiangsu University, with 85.5% sensitivity and 89.0% specificity in The Second Affiliated Hospital of Soochow University). Moreover, our novel prognostic assessment model has a high value in identifying poor prognosis patients in the validation groups from The Affiliated Kunshan Hospital of Jiangsu University (χ² = 8.461, P = .004), and The Second Affiliated Hospital of Soochow University (χ² = 7.844, P = .005).

CONCLUSIONS

The diagnostic and prognostic assessment models we have established are of great value in the diagnosis and prognostic evaluation of ischemic stroke.

Downregulation of long non‑coding RNA ANRIL promotes proliferation and migration in hypoxic human pulmonary artery smooth muscle cells

Pulmonary arterial hypertension (PAH) is a progressive syndrome. When PAH occurs, the circulatory resistance of the pulmonary vasculature will gradually increase, which may lead to right heart failure and death. Pathological features of PAH include abnormal proliferation of pulmonary vascular smooth muscle cells and pulmonary vascular remodeling. Hypoxia is the main cause of PAH, which directly induces the contraction and proliferation of pulmonary artery smooth muscle cells (PASMCs), and eventually leads to pulmonary vascular remodeling. Recent studies have shown that long non-coding RNAs (lncRNAs) play key roles in numerous biological processes, including cell proliferation and the occurrence and development of cardiovascular diseases. Studies have also shown that lncRNA antisense noncoding RNA in the INK4 locus (ANRIL) can promote the proliferation of vascular smooth muscle cells. Therefore, the hypothesis of the present study was that ANRIL may be expressed in PASMCs and play a regulatory role. In this study, the expression of ANRIL was analyzed by quantitative PCR. The effects of ANRIL on human pulmonary artery smooth muscle cells (HPASMCs) were assessed by MTT assay, flow cytometry, bromodeoxyuridine incorporation assay, Transwell assay, scratch-wound assay, immunofluorescence assay and western blotting. These experiments revealed that the expression of ANRIL was significantly downregulated in HPASMCs induced by hypoxia. The downregulation of ANRIL affected the cell cycle, making more HPASMCs move from the G0/G1 phase to the G2/M+S phase and strengthening the cell proliferation. Moreover, downregulated ANRIL increased the migration of HPASMCs under hypoxia. This study identified ANRIL as a critical regulator in HPASMCs induced by hypoxia and demonstrated the potential of gene therapy and drug development for treating PAH.

ANRIL and atherosclerosis

WHAT IS KNOWN AND OBJECTIVE

The 3.8-kb-long antisense non-coding RNA at the INK4 locus (ANRIL) is transcribed from the short arm of human chromosome 9 on P21 and is associated with malfunction of the vascular endothelium, vascular smooth muscle cell (VSMC) proliferation/migration/senescence/apoptosis, mononuclear cell adhesion and proliferation, glycolipid metabolism disorder and DNA damage. Hence, ANRIL plays an important role in atherogenesis. Moreover, genome-wide association studies (GWAS) have identified ANRIL as a biomarker that is closely related to coronary heart disease (CHD). The objective of this review was to discuss the pathological mechanism of ANRIL in atherosclerotic development and its significance as a predictor of cardiovascular disease.

METHODS

Review of the PubMed, EMBASE and Cochrane databases for articles demonstrating the roles of ANRIL in the development of atherosclerotic diseases.

RESULTS AND DISCUSSION

The abnormal expression of ANRIL is linked to vascular endothelium injury; the proliferation, migration, senescence and apoptosis of VSMCs; mononuclear cell adhesion and proliferation; glycolipid metabolism disorder; DNA damage; and competing endogenous RNAs. Moreover, ANRIL accelerates the progression of CHD by regulating its single nucleotide polymorphisms (SNPs).

WHAT IS NEW AND CONCLUSION

Considering that ANRIL accelerates atherosclerosis (AS) development and is a risk factor for CHD, it is reasonable for us to explore an efficacious ANRIL-based therapy for AS in CHD.

High Positive Correlations between ANRIL and p16-CDKN2A/p15-CDKN2B/p14-ARF Gene Cluster Overexpression in Multi-Tumor Types Suggest Deregulated Activation of an ANRIL-ARF Bidirectional Promoter

The CDKN2B-AS1 gene, also called ANRIL, is located at the human CDKN2A/B locus at 9p21.3 and transcribed by RNA polymerase II into a long non-coding RNA of 3834 bp. The CDKN2B-AS1 gene overlaps a critical region of 125 kb covering the CDKN2B gene. The CDKN2A/B locus encompasses three major tumor suppressors juxtaposed and joined into a p16-CDKN2A/p15-CDKN2B/p14-ARF gene cluster. CDKN2A encodes splice variants p16-CDKN2A and p14-ARF, and CDKN2B encodes p15-CDKN2B. ANRIL shares a bidirectional promoter with the p14-ARF gene and is transcribed from the opposite strand to the cluster. We performed an analysis of the expression level of ANRIL and tumor suppressor p16-CDKN2A, p15-CDKN2B, and p14-ARF genes using quantitative RT-PCR in a multitumor panel. We observed the overexpression of the four genes ANRIL, p16-CDKN2A, p15-CDKN2B, and p14-ARF in the great majority of the 17 different cancer types. ANRIL was upregulated in 13/17 tumors compared to normal tissues, ranging from 5% (prostate cancer) to 91% (cervix cancer), with variable expression of p16-CDKN2A, p15-CDKN2B, and p14-ARF genes. A high positive correlation was identified between levels of expression of ANRIL and the three tumor suppressors. The strongest positive association was observed with p14-ARF (p < 0.001) in all but one (lung squamous cell carcinoma) of the examined tumor types. This correlation suggests coordinated deregulated mechanisms in all cancer types through aberrant activation of a bidirectional p14-ARF/ANRIL promoter. Furthermore, significant positive correlation was unexpectedly established in prostatic carcinomas, in contradiction with previous data.

Diagnostic value of circulating lncRNA ANRIL and its correlation with coronary artery disease parameters

This study aimed to detect the expression of the long non-coding RNA (lncRNA) antisense non-coding RNA in the INK4 locus (ANRIL) and evaluate its correlation with disease risk, stenosis degree, inflammation, as well as overall survival (OS) in coronary artery disease (CAD) patients. A total of 230 patients who underwent diagnostic coronary angiography were consecutively recruited and assigned to CAD group (n=125) or control group (n=105) according to presence or absence of CAD. Gensini score was calculated to assess the severity of coronary artery damage. Plasma samples were collected and the expression ANRIL was detected in all participants. High-sensitivity C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), and cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-8, IL-10, and IL-17 in CAD patients were measured and OS was calculated. The relative expression of ANRIL was higher in CAD patients compared to controls (P<0.001). Receiver operating characteristic disclosed that ANRIL could distinguish CAD patients from controls with an area under the curve of 0.789 (95%CI: 0.731–0.847). Spearman's rank correlation test revealed that expression of ANRIL was positively correlated with Gensini score (P=0.001), levels of hs-CRP (P=0.001), ESR (P=0.038), TNF-α (P=0.004), and IL-6 (P<0.001), while negatively correlated with IL-10 level (P=0.008) in CAD patients. Kaplan-Meier curve revealed that high expression of ANRIL was associated with shorter OS (P=0.013). In conclusion, circulating ANRIL presented a good diagnostic value for CAD, and its high expression was associated with increased stenosis degree, raised inflammation, and poor OS in CAD patients.

Interfering with long chain noncoding RNA ANRIL expression reduces heart failure in rats with diabetes by inhibiting myocardial oxidative stress

This study is performed to elucidate whether long-chain noncoding RNA ANRIL has an effect on diabetes, and further explore the mechanism of ANRIL in diabetes. The rat model of diabetes was established via intraperitoneal injection of streptozotocin. The modeled rats were grouped into normal, diabetes, siRNA-NC, and ANRIL siRNA groups. Besides, the expression of ANRIL, cardiac function, inflammatory factor levels, cardiomyocyte apoptosis, and levels of oxidative stress index were all determined. Upregulated ANRIL was found in myocardial tissue of diabetic rats. Downregulated ANRIL improved cardiac function index and the expression of inflammatory factors, improved the pathological state of myocardial tissue and myocardial remodeling, decreased myocardial collagen deposition area and cardiomyocyte apoptosis and reduced the oxidative level of myocardial tissue in diabetic rats. This present study suggests that upregulated ANRIL is found in myocardial tissue of diabetic rats. Additionally, silencing of ANRIL reduces myocardial injury in diabetes by inhibiting myocardial oxidative stress.

Epigenetics and vascular diseases

Cardiovascular disease remains the number one cause of death and disability worldwide despite significant improvements in diagnosis, prevention, and early intervention efforts. There is an urgent need for improved understanding of cardiovascular processes responsible for disease development in order to develop more effective therapeutic strategies. Recent knowledge gleaned from the study of epigenetic mechanisms in the vasculature has uncovered new potential targets for intervention. Herein, we provide an overview of epigenetic mechanism, and review recent findings related to epigenetics in vascular diseases, highlighting classical epigenetic mechanism such as DNA methylation and histone modification as well as the newly discovered non-coding RNA mechanisms.

Targeting epigenetics and non-coding RNAs in atherosclerosis: from mechanisms to therapeutics

Atherosclerosis, the principal cause of cardiovascular death worldwide, is a pathological disease characterized by fibro-proliferation, chronic inflammation, lipid accumulation, and immune disorder in the vessel wall. As the atheromatous plaques develop into advanced stage, the vulnerable plaques are prone to rupture, which causes acute cardiovascular events, including ischemic stroke and myocardial infarction. Emerging evidence has suggested that atherosclerosis is also an epigenetic disease with the interplay of multiple epigenetic mechanisms. The epigenetic basis of atherosclerosis has transformed our knowledge of epigenetics from an important biological phenomenon to a burgeoning field in cardiovascular research. Here, we provide a systematic and up-to-date overview of the current knowledge of three distinct but interrelated epigenetic processes (including DNA methylation, histone methylation/acetylation, and non-coding RNAs), in atherosclerotic plaque development and instability. Mechanistic and conceptual advances in understanding the biological roles of various epigenetic modifiers in regulating gene expression and functions of endothelial cells (vascular homeostasis, leukocyte adhesion, endothelial-mesenchymal transition, angiogenesis, and mechanotransduction), smooth muscle cells (proliferation, migration, inflammation, hypertrophy, and phenotypic switch), and macrophages (differentiation, inflammation, foam cell formation, and polarization) are discussed. The inherently dynamic nature and reversibility of epigenetic regulation, enables the possibility of epigenetic therapy by targeting epigenetic "writers", "readers", and "erasers". Several Food Drug Administration-approved small-molecule epigenetic drugs show promise in pre-clinical studies for the treatment of atherosclerosis. Finally, we discuss potential therapeutic implications and challenges for future research involving cardiovascular epigenetics, with an aim to provide a translational perspective for identifying novel biomarkers of atherosclerosis, and transforming precision cardiovascular research and disease therapy in modern era of epigenetics.

Noncoding RNAs in the Vascular System Response to Oxidative Stress

SIGNIFICANCE

Redox homeostasis plays a pivotal role in vascular cell function and its imbalance has a causal role in a variety of vascular diseases. Accordingly, the response of mammalian cells to redox cues requires precise transcriptional and post-transcriptional modulation of gene expression patterns. Recent Advances: Mounting evidence shows that nonprotein-coding RNAs (ncRNAs) are important for the functional regulation of most, if not all, cellular processes and tissues. Not surprisingly, a prominent role of ncRNAs has been identified also in the vascular system response to oxidative stress.

CRITICAL ISSUES

The highly heterogeneous family of ncRNAs has been divided into several groups. In this article we focus on two classes of regulatory ncRNAs: microRNAs and long ncRNAs (lncRNAs). Although knowledge in many circumstances, and especially for lncRNAs, is still fragmentary, ncRNAs are clinically interesting because of their diagnostic and therapeutic potential. We outline ncRNAs that are regulated by oxidative stress as well as ncRNAs that modulate reactive oxygen species production and scavenging. More importantly, we describe the role of these ncRNAs in vascular physiopathology and specifically in disease conditions wherein oxidative stress plays a crucial role, such as hypoxia and ischemia, ischemia reperfusion, inflammation, diabetes mellitus, and atherosclerosis.

FUTURE DIRECTIONS

The therapeutic potential of ncRNAs in vascular diseases and in redox homeostasis is discussed.

LncRNA-ANRIL inhibits cell senescence of vascular smooth muscle cells by regulating miR-181a/Sirt1

BACKGROUND

Cardiovascular disease is one of the major threats to human life and health, and vascular aging is an important cause of its occurrence. Antisense non-coding RNA in the INK4 locus (ANRIL) is a kind of long non-coding RNA (lncRNA) that plays important roles in cell senescence. However, the role and mechanism of ANRIL in senescence of vascular smooth muscle cells (VSMCs) are unclear.

METHODS

Cell viability and cell cycle were evaluated using an MTT assay and flow cytometry analysis, respectively. Senescence-associated (SA)-β-galactosidase (gal) staining was used to determine cell senescence. Dual luciferase reporter assays were conducted to confirm the binding of ANRIL and miR-181a, as well as miR-181a and Sirt1. The expression of ANRIL, miR-181a, and Sirt1 was determined using qRT-PCR and protein levels of SA-β-gal and p53-p21 pathway-related proteins were evaluated by Western blotting.

RESULTS

ANRIL and Sirt1 were down-regulated, whereas miR-181a was up-regulated in aging VSMCs. In young and aging VSMCs, over-expression of ANRIL could down-regulate miR-181a and up-regulate Sirt1. MTT and SA-β-gal staining assays showed that over-expression of ANRIL and inhibition of miR-181a promoted cell viability and inhibited VSMC senescence. The dual-luciferase reporter assay determined that miR-181a directly targets ANRIL and the 3'-UTR of Sirt1. Furthermore, over-expression of ANRIL inhibited cell cycle arrest and the p53-p21 pathway.

CONCLUSION

ANRIL promotes cell viability and inhibits senescence in VSMCs, possibly by regulating miR-181a/Sirt1, and alleviating cell cycle arrest by inhibiting the p53-p21 pathway. This study provides novel insights for the role of ANRIL in the development of cell senescence.

Down-regulation of myocardial infarction associated transcript 1 improves myocardial ischemia-reperfusion injury in aged diabetic rats by inhibition of activation of NF-κB signaling pathway

OBJECTIVE

This study is performed to investigate the effect of long chain noncoding RNA myocardial infarction associated transcript 1 (MIRT1) on myocardial ischemia reperfusion (I/R) injury in aged diabetic rats.

METHODS

The aged diabetic rat model and myocardial I/R injury model were established. Through injecting MIRT1 siRNA into caudal vein of rats, the cardiac function, myocardial pathological injury, myocardial fibrosis, cardiomyocytes apoptosis, oxidative stress and inflammatory injury of myocardial tissue of rats were measured.

RESULTS

For diabetic I/R rats, the expression of MIRT1 in myocardial tissue was increased, the activation of nuclear factor kappa B (NF-κB) signaling pathway was increased, the degree of damage to cardiac function was aggravated, the area of myocardial pathological injury and myocardial fibrosis was enlarged, the degree of cardiomyocytes apoptosis was increased, the degree of oxidative stress and inflammatory injury was increased. After inhibiting the expression of MIRT1, the activation of NF-κB signaling pathway was inhibited, the damage of cardiac function and cardiomyopathy was alleviated, the area of myocardial fibrosis was decreased, the degree of myocardial apoptosis was decreased, the degree of oxidative stress and inflammatory injury was obviously improved.

CONCLUSION

Our study highlights that down-regulation of MIRT1 improves myocardial I/R injury in aged diabetic rats by inhibition of activation of NF-κB signaling pathway.

Long Noncoding RNA ANRIL: Lnc-ing Genetic Variation at the Chromosome 9p21 Locus to Molecular Mechanisms of Atherosclerosis

Ever since the first genome-wide association studies (GWAS) on coronary artery disease (CAD), the Chr9p21 risk locus has emerged as a top signal in GWAS of atherosclerotic cardiovascular disease, including stroke and peripheral artery disease. The CAD risk SNPs on Chr9p21 lie within a stretch of 58 kilobases of non-protein-coding DNA, containing the gene body of the long noncoding RNA (lncRNA) antisense non coding RNA in the INK4 locus (ANRIL). How risk is affected by the Chr9p21 locus in molecular detail is a matter of ongoing research. Here we will review recent advances in the understanding that ANRIL serves as a key risk effector molecule of atherogenesis at the locus. One focus of this review is the shift in understanding that genetic variation at Chr9p21 not only affects the abundance of ANRIL, and in some cases expression of the adjacent CDKN2A/B tumor suppressors, but also impacts ANRIL splicing, such that 3′-5′-linked circular noncoding ANRIL RNA species are produced. We describe how the balance of linear and circular ANRIL RNA, determined by the Chr9p21 genotype, regulates molecular pathways and cellular functions involved in atherogenesis. We end with an outlook on how manipulating circular ANRIL abundance may be exploited for therapeutic purposes.