Non-coding RNAs in cardiovascular ageing

RNA modifications in aging-associated cardiovascular diseases

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide that bears an enormous healthcare burden and aging is a major contributing factor to CVDs. Functional gene expression network during aging is regulated by mRNAs transcriptionally and by non-coding RNAs epi-transcriptionally. RNA modifications alter the stability and function of both mRNAs and non-coding RNAs and are involved in differentiation, development, and diseases. Here we review major chemical RNA modifications on mRNAs and non-coding RNAs, including N6-adenosine methylation, N1-adenosine methylation, 5-methylcytidine, pseudouridylation, 2′ -O-ribose-methylation, and N7-methylguanosine, in the aging process with an emphasis on cardiovascular aging. We also summarize the currently available methods to detect RNA modifications and the bioinformatic tools to study RNA modifications. More importantly, we discussed the specific implication of the RNA modifications on mRNAs and non-coding RNAs in the pathogenesis of aging-associated CVDs, including atherosclerosis, hypertension, coronary heart diseases, congestive heart failure, atrial fibrillation, peripheral artery disease, venous insufficiency, and stroke.

LncRNA LOC105378097 inhibits cardiac mitophagy in natural ageing mice

BACKGROUND

The development of heart ageing is the main cause of chronic disability, disease and death in the elderly. Ample evidence has established a pivotal role for significantly reduced mitophagy in the ageing heart. However, the underlying mechanisms of mitophagy deficiency in ageing heart are little known. The present study aimed to explore the underlying mechanisms of lncRNA LOC105378097 (Senescence-Mitophagy Associated LncRNA, lncR-SMAL) actions on mitophagy in the setting of heart ageing.

METHODS

The expression of lncR-SMAL was measured in serum from different ages of human and heart from different ages of mice through a quantitative real-time polymerase chain reaction. The effects of lncR-SMAL on heart function of mice were assessed by echocardiography and pressure-volume measurements system. Cardiac senescence was evaluated by hematoxylin-eosin staining, senescence-associated β-galactosidase staining, flow cytometry and western blot analysis of expression of ageing related markes p53 and p21. Cardiomyocyte mitophagy was assessed by western blot, mRFP-GFP-LC3 adenovirus particles transfection and mito-Keima staining. Interaction between lncR-SMAL and Parkin was validated through molecular docking, RNA immunoprecipitation (RIP) and RNA pull-down assay. Ubiquitination assay was performed to explore the molecular mechanism of Parkin inhibition. The effects of lncR-SMAL on mitochondrial function were investigated through electron microscopic examination, JC-1 staining and oxygen consumption rates analysis.

RESULTS

The heart-enriched lncR-SMAL reached the expression crest in the serum of human at an age of 60. Exogenously overexpression of lncRNA SMAL deteriorated cardiac function exactly as natural ageing and inhibited the associated cardiomyocytes mitophagy by depressing Parkin protein level. Improved heart ageing and mitophagy caused by Parkin overexpression were reversed by lncR-SMAL in mice. In contrast, the loss of lncR-SMAL in AC16 cells induced the upregulation of Parkin protein and ameliorated mitophagy and mitochondrial dysfunction, resulting in alleviated cardiac senescence. Besides, we found the interaction between lncR-SMAL and Parkin protein through computational docking analysis, pull-down and RIP assay. This would contribute to the promotive effect of lncR-SMAL on Parkin ubiquitination and decrease Parkin protein stability.

CONCLUSIONS

The present study for the first time demonstrates a heart-enriched lncRNA, SMAL, that inhibits the mitophagy of cardiomyocytes via the downregulation of Parkin protein, which further contributes to heart ageing and cardiac dysfunction in natural ageing mice.

MiR-29a Increase in Aging May Function as a Compensatory Mechanism Against Cardiac Fibrosis Through SERPINH1 Downregulation

Deregulation of microRNA (miRNA) profile has been reportedly linked to the aging process, which is a dominant risk factor for many pathologies. Among the miRNAs with documented roles in aging-related cardiac diseases, miR-18a, -21a, -22, and -29a were mainly associated with hypertrophy and/or fibrosis; however, their relationship to aging was not fully addressed before. The purpose of this paper was to evaluate the variations in the expression levels of these miRNAs in the aging process. To this aim, multiple organs were harvested from young (2–3-months-old), old (16–18-months-old), and very old (24–25-months-old) mice, and the abundance of the miRNAs was evaluated by quantitative real-time (RT)-PCR. Our studies demonstrated that miR-21a, miR-22, and miR-29a were upregulated in the aged heart. Among them, miR-29a was highly expressed in many other organs, i.e., the brain, the skeletal muscle, the pancreas, and the kidney, and its expression was further upregulated during the natural aging process. Western blot, immunofluorescence, and xCELLigence analyses concurrently indicated that overexpression of miR-29a in the muscle cells decreased the collagen levels as well as cell migration and proliferation. Computational prediction analysis and overexpression studies identified SERPINH1, a specific chaperone of procollagens, as a potential miR-29a target. Corroborating to this, significantly downregulated SERPINH1 levels were found in the skeletal muscle, the heart, the brain, the kidney, and the pancreas harvested from very old animals, thereby indicating the role of the miR-29a-SERPINH1 axis in the aging process. In vitro analysis of miR-29a effects on fibroblast and cardiac muscle cells pointed toward a protective role of miR-29a on aging-related fibrosis, by reducing cell migration and proliferation. In conclusion, our study indicates an adaptive increase of miR-29 in the natural aging process and suggests its role as a transcriptional repressor of SERPINH1, with a potential therapeutic value against adverse matrix remodeling and aging-associated tissue fibrosis.

Ageing and Obesity Shared Patterns: From Molecular Pathogenesis to Epigenetics

In modern societies, ageing and obesity represent medical challenges for healthcare professionals and caregivers. Obesity and ageing share common features including the related cellular and molecular pathways as well as the impacts they have as risk factors for a variety of diseases and health problems. Both of these health problems also share exercise and a healthy lifestyle as the best therapeutic options. Importantly, ageing and obesity also have common epigenetic changes (histone modification, DNA methylation, noncoding RNAs, and chromatin remodeling) that are also impacted by exercise. This suggests that epigenetic pathways are among the mechanisms via which exercise induces its benefits, including ageing and obesity improvements. Exploring these interrelations and based on the fact that both ageing and obesity represent risk factors for each other, would lead to optimizing the available therapeutic approaches towards improved obesity management and healthy ageing.

The emerging role of circular RNAs in cardiovascular diseases

Cardiovascular disease (CVD) is one of the vital causes of morbidity and mortality, and the number of deaths from CVD has increased worldwide. Circular RNAs (circRNAs) is a novel type of endogenous noncoding RNA, which can form covalent closed continuous rings and are highly expressed in the eukaryotic transcriptome. In recent years, research on circRNAs have been increasing and the researchers have also become cumulatively aware of the association between circRNAs and CVD. This review highlights the biogenesis and functions of circRNAs and the role in cardiovascular diseases.

The role of exosomal non-coding RNAs in aging-related diseases

Aging is a biological process caused by the accumulation of senescent cells with a permanent proliferative arrest. To the influence of aging on human life expectancy, there is essential for new biomarkers which possibly will assistance in recognizing age-associated pathologies. Exosomes, which are cell-secreted nanovesicles, make available a new biomarker detection and therapeutic approach for the transfer of different molecules with high capacity. Recently, non-coding RNAs (ncRNA) which are contained in exosomes have developed as important molecules regulating the complexity of aging and relevant human diseases. The discovery of ncRNA provided perceptions into an innovative regulatory platform that could interfere with cellular senescence. The non-coding transcriptome includes a different of RNA species, spanning from short ncRNAs (<200 nucleotides) to long ncRNAs, that are >200 bp long. Upgraded evidence displays that targeting ncRNAs possibly will influence senescence pathways. In this article, we will address ncRNAs that participated in age-related and cellular senescence diseases. Growing conception of ncRNAs in the aging process possibly will be responsible for new understandings into the improvement of age-related diseases and elongated life span.

CALINCA-A Novel Pipeline for the Identification of lncRNAs in Podocyte Disease

Diseases of the renal filtration unit-the glomerulus-are the most common cause of chronic kidney disease. Podocytes are the pivotal cell type for the function of this filter and focal-segmental glomerulosclerosis (FSGS) is a classic example of a podocytopathy leading to proteinuria and glomerular scarring. Currently, no targeted treatment of FSGS is available. This lack of therapeutic strategies is explained by a limited understanding of the defects in podocyte cell biology leading to FSGS. To date, most studies in the field have focused on protein-coding genes and their gene products. However, more than 80% of all transcripts produced by mammalian cells are actually non-coding. Here, long non-coding RNAs (lncRNAs) are a relatively novel class of transcripts and have not been systematically studied in FSGS to date. The appropriate tools to facilitate lncRNA research for the renal scientific community are urgently required due to a row of challenges compared to classical analysis pipelines optimized for coding RNA expression analysis. Here, we present the bioinformatic pipeline CALINCA as a solution for this problem. CALINCA automatically analyzes datasets from murine FSGS models and quantifies both annotated and de novo assembled lncRNAs. In addition, the tool provides in-depth information on podocyte specificity of these lncRNAs, as well as evolutionary conservation and expression in human datasets making this pipeline a crucial basis to lncRNA studies in FSGS.

LncRNA Xist induces arterial smooth muscle cell apoptosis in thoracic aortic aneurysm through miR-29b-3p/Eln pathway

BACKGROUND

Thoracic aortic aneurysm (TAA) is a serious disease usually happening in elder people and with high death rate. Accumulating studies have reported that long non-coding RNAs (lncRNAs) are implicated in the progression of various human diseases, including TAA.

AIM

In our study, we intended to explore the function of elastin (Eln) and its upstream mechanism in TAA.

METHODS

RT-qPCR determined gene expressions and western blot tested changes in protein levels. Ang Ⅱ treatment was implemented to induce cell apoptosis. Flow cytometry analysis, TUNEL assay and JC-1 assay were exploited to measure cell apoptosis. Meanwhile, mechanistic assays such as RIP, RNA pull down and luciferase reporter assays were employed to identify the interplay between RNAs.

RESULTS

Eln inhibition was identified to protect rat arterial smooth muscle cells from apoptosis. Also, miR-29b-3p was identified to bind to Eln, and X inactive specific transcript (Xist) could boost Eln expression through absorbing miR-29b-3p. Meanwhile, Eln overexpression counteracted the suppression of silenced Xist on the apoptosis of rat arterial smooth muscle cells. More importantly, such ceRNA network was proved to aggravate the apoptosis of human aortic smooth muscle cells.

CONCLUSION

LncRNA Xist contributes to arterial smooth muscle cell apoptosis through miR-29b-3p/Eln pathway, providing new potential roads for treating TAA.

Roles and Functions of Exosomal Non-coding RNAs in Vascular Aging

Aging is a progressive loss of physiological integrity and functionality process which increases susceptibility and mortality to diseases. Vascular aging is a specific type of organic aging. The structure and function changes of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are the main cause of vascular aging, which could influence the threshold, process, and severity of vascular related diseases. Accumulating evidences demonstrate that exosomes serve as novel intercellular information communicator between cell to cell by delivering variety biologically active cargos, especially exosomal non-coding RNAs (ncRNAs), which are associated with most of aging-related biological and functional disorders. In this review, we will summerize the emerging roles and mechanisms of exosomal ncRNAs in vascular aging and vascular aging related diseases, focusing on the role of exosomal miRNAs and lncRNAs in regulating the functions of ECs and VSMCs. Moreover, the relationship between the ECs and VSMCs linked by exosomes, the potential diagnostic and therapeutic application of exosomes in vascular aging and the clinical evaluation and treatment of vascular aging and vascular aging related diseases will also be discussed.

Mechanisms of Vascular Aging

Aging of the vasculature plays a central role in morbidity and mortality of older people. To develop novel treatments for amelioration of unsuccessful vascular aging and prevention of age-related vascular pathologies, it is essential to understand the cellular and functional changes that occur in the vasculature during aging. In this review, the pathophysiological roles of fundamental cellular and molecular mechanisms of aging, including oxidative stress, mitochondrial dysfunction, impaired resistance to molecular stressors, chronic low-grade inflammation, genomic instability, cellular senescence, epigenetic alterations, loss of protein homeostasis, deregulated nutrient sensing, and stem cell dysfunction in the vascular system are considered in terms of their contribution to the pathogenesis of both microvascular and macrovascular diseases associated with old age. The importance of progeronic and antigeronic circulating factors in relation to development of vascular aging phenotypes are discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay age-related vascular pathologies by targeting fundamental cellular and molecular aging processes are presented.

Aging is an adaptation that selects in animals against disruption of homeostasis

During evolution, Muller's ratchet permanently generates deleterious germline mutations that eventually must be defused by selection. It seems widely held that cancer and aging-related diseases (ARDs) cannot contribute to this germline gene selection because they tail reproduction and thus occur too late, at the end of the life cycle. Here we posit however that by lessening the offspring's survival by proxy through diminishing parental care, they can still contribute to the selection. The hypothesis in detail: The widespread occurrence of aging in animals suggests that it is an adaptation. But to what benefit? Aging seems to have only drawbacks. In humans, ARDs cause today almost all mortality; they include heart disease, cerebrovascular disease, Alzheimer's disease, kidney disease and cancer. Compensation seems unthinkable. For cancer, the author proposed in a previous study a benefit to the species: purifying selection against deleterious germline genes that when expressed enhance intracellular energy dissipation. This multicausal energy dissipation, posited as the universal origin of cancer initiation, relates to cellular heat generation, disrupted metabolism, and inflammation. The organism reproduces during cancer's dormancy, and when approaching its end of life, the onset of cancer is accelerated in proportion to the cancer-initiating signal. Through cancer, the organism, now a parent, implements the self-actuated programmed death of Skulachev's phenoptosis. This "first death" enhances by proxy the offspring's chance of "second death" (or "double death") through diminished parental care. Repetition over generations realizes a purifying selection against genes causing energy dissipation. The removal of the deleterious germline gene mutations permanently generated by Muller's ratchet gives a benefit. We generalize, motivated by the parallels between cancer and aging, the purifying selection posited for cancer to aging. An ARD would be initiated in the organ by multicausal disruption of homeostasis, and be followed by dormancy and senescence until its onset near the end of the life cycle. Just as for cancer, the ARD eventually enhances double death, and the realized permanent selection gives a benefit to the species through the selection against germ line genes that disrupt homeostasis. Given their similarities, cancer and aging are combined in the posited Unified Cancer-Aging Adaptation (UCAA) model, which may be confirmed by next-generation sequencing data. Also because of the emerging important role of cellular senescence, the hypothesis may guide the development of therapies against both cancer and aging.

Expression pattern of genome-scale long noncoding RNA following acute myocardial infarction in Chinese Uyghur patients

In this study, we examined the long noncoding RNA (lncRNA) expression pattern in Uyghur patients (a minority of China) with acute myocardial infarction (AMI) on a genome-wide scale. Total RNAs were extracted from the peripheral blood of 55 Uyghur AMI patients and 55 healthy volunteers. The expression levels of genome-wide scale lncRNAs and mRNAs were determined by microarray in 10 samples (5 AMI and 5 controls). qRT-PCR was used to validate lncRNA expression levels in 100 samples (50 AMI and 50 controls). Data analyses were performed using R and Bioconductor. A total of 3624 up- and 1637 down-regulated lncRNAs were identified to be significantly and differentially expressed between these two groups. The annotation result of their co-expressed mRNAs showed that the most significantly related category of GO analysis was regulation of biological processes, and the most significantly related pathway was apoptosis and its corresponding p53. The microarray identified ENST00000416860.2, ENST00000421157.1 and TCONS_00025701 lncRNAs were confirmed by qRT-PCR. Our study indicated that clusters of lncRNAs were significantly and differentially expressed in the peripheral blood of AMI patients when compared with healthy controls within the Uyghur population. These newly identified lncRNAs may have a potential role in the development of AMI.

miR-21 suppression prevents cardiac alterations induced by d-galactose and doxorubicin

d-galactose (d-gal)-induced cardiac alterations and Doxorubicin (Dox)-induced cardiomyocyte senescence are commonly used models to study cardiac aging. Accumulating evidence has suggested that microRNAs (miRNAs, miRs) are critically involved in the regulation of cellular and organismal aging and age-related diseases. However, little has been revealed about the roles of miRNAs in cardiac alterations induced by d-gal and Dox. In this study, we used miRNA arrays to investigate the dysregulated miRNAs in heart samples from 15month-old versus 2month-old male C57BL/6 mice and further validated them in d-gal-induced pseudo-aging mouse model and Dox-induced cardiomyocyte senescence in vitro model. We confirmed a significant increase of miR-21 in all these models by quantitative reverse transcription polymerase chain reactions. We further demonstrated that miR-21 was able to promote Dox-induced cardiomyocyte senescence whereas suppression of miR-21 could prevent that, as determined by percentage of β-gal-positive cells and gene markers of aging. Phosphatase and tensin homolog (PTEN) was identified as a target gene of miR-21, mediating its effect in increasing cardiomyocyte senescence. Finally, we found that miR-21 knockout mice were resistant to d-gal-induced alterations in aging-markers and cardiac function. Collectively, this study provides direct evidence that inhibition of miR-21 is protective against d-gal-induced cardiac alterations and Dox-induced cardiomyocyte senescence via targeting PTEN. Inhibition of miR-21 might be a novel strategy to combat cardiac aging.

Noncoding RNAs in Cardiovascular Aging

With a progressively growing elderly population, aging-associated cardiovascular diseases and other pathologies have brought great burden to the economy, society, and individuals. Therefore, identifying therapeutic targets and developing effective strategies to prevent from cardiovascular aging are highly needed. Accumulating evidences suggest that noncoding RNAs (ncRNAs) such as microRNAs and long noncoding RNAs (lncRNAs) play important roles in regulating gene expression, which contributes to many pathophysiological processes of cellular senescence, aging, and aging-related diseases in cardiovascular systems. Here we provided a general overview of ncRNAs as well as the underlying mechanisms involved in cardiovascular aging. Although the importance of ncRNAs in cardiovascular aging has been reported and commonly acknowledged, further studies are still necessary to elucidate the underlying molecular mechanisms.

Arterial ageing: from endothelial dysfunction to vascular calcification

Complex structural and functional changes occur in the arterial system with advancing age. The aged artery is characterized by changes in microRNA expression patterns, autophagy, smooth muscle cell migration and proliferation, and arterial calcification with progressively increased mechanical vessel rigidity and stiffness. With age the vascular smooth muscle cells modify their phenotype from contractile to 'synthetic' determining the development of intimal thickening as early as the second decade of life as an adaptive response to forces acting on the arterial wall. The increased permeability observed in intimal thickening could represent the substrate on which low-level atherosclerotic stimuli can promote the development of advanced atherosclerotic lesions. In elderly patients the atherosclerotic plaques tend to be larger with increased vascular stenosis. In these plaques there is a progressive accumulation of both lipids and collagen and a decrease of inflammation. Similarly the plaques from elderly patients show more calcification as compared with those from younger patients. The coronary artery calcium score is a well-established marker of adverse cardiovascular outcomes. The presence of diffuse calcification in a severely stenotic segment probably induces changes in mechanical properties and shear stress of the arterial wall favouring the rupture of a vulnerable lesion in a less stenotic adjacent segment. Oxidative stress and inflammation appear to be the two primary pathological mechanisms of ageing-related endothelial dysfunction even in the absence of clinical disease. Arterial ageing is no longer considered an inexorable process. Only a better understanding of the link between ageing and vascular dysfunction can lead to significant advances in both preventative and therapeutic treatments with the aim that in the future vascular ageing may be halted or even reversed.

Candidate biomarkers in heart failure with reduced and preserved ejection fraction

CONTEXT

Patients presenting with heart failure symptoms are categorized into heart failure (HF) with reduced and preserved ejection fraction.

OBJECTIVE

Aim is to investigate the additional use of candidate biomarkers to characterize patients with either sub-type of HF.

METHODS

Literature search was conducted in the electronic databases MEDLINE and Cochrane Central Register of Controlled Trials from inception through November 2014.

RESULTS

The results of 47 diseased and general population cohorts were included.

CONCLUSION

Current studies could outline the additional use of candidate biomarkers especially GDF-15, MR-proADM and high-sensitive determined troponin, although major outcome studies are still missing.

Emerging roles of lncRNAs in senescence

Cellular senescence is a complex stress response that leads to an irreversible state of cell growth arrest. Senescence may be induced by various stimuli such as telomere shortening, DNA damage or oncogenic insult, among others. Senescent cells are metabolically highly active, producing a wealth of cytokines and chemokines that, depending on the context, may have a beneficial or deleterious effect on the organism. Senescence is considered a tightly regulated stress response that is largely governed by the p53/p21 and p16/Rb pathways. Many molecules have been identified as regulators of these two networks, such as transcription factors, chromatin modifiers and non-coding RNAs. The expression level of several long non-coding RNAs is affected during different types of senescence; however, which of these are important for the biological function remains poorly understood. Here we review our current knowledge of the mechanistic roles of lncRNAs affecting the main senescence pathways, and discuss the importance of identifying new regulators.

Modulation of Hypercholesterolemia-Induced Oxidative/Nitrative Stress in the Heart

Hypercholesterolemia is a frequent metabolic disorder associated with increased risk for cardiovascular morbidity and mortality. In addition to its well-known proatherogenic effect, hypercholesterolemia may exert direct effects on the myocardium resulting in contractile dysfunction, aggravated ischemia/reperfusion injury, and diminished stress adaptation. Both preclinical and clinical studies suggested that elevated oxidative and/or nitrative stress plays a key role in cardiac complications induced by hypercholesterolemia. Therefore, modulation of hypercholesterolemia-induced myocardial oxidative/nitrative stress is a feasible approach to prevent or treat deleterious cardiac consequences. In this review, we discuss the effects of various pharmaceuticals, nutraceuticals, some novel potential pharmacological approaches, and physical exercise on hypercholesterolemia-induced oxidative/nitrative stress and subsequent cardiac dysfunction as well as impaired ischemic stress adaptation of the heart in hypercholesterolemia.

Differential lncRNA‑mRNA co‑expression network analysis revealing the potential regulatory roles of lncRNAs in myocardial infarction

Previous studies have reported that long, non-coding RNAs (lncRNAs) are important in cardiovascular disease. However, the lncRNAs involved in myocardial infarction and their detailed mechanism have not been well characterized. In the present study, an affymetrix microarray associated with myocardial infarction was re-annotated, following which a myocardial infarction-related differential lncRNA-mRNA co-expression network (MILMN) was constructed. Subsequently, pathway enrichment analysis was used for all the mRNAs in the MILMN, and an lncRNA-pathway network was constructed. It was found that the mRNAs were predominantly involved in certain cardiovascular disease-associated pathway, for example the dilated cardiomyopathy and mitogen-activated protein kinase signaling pathway. Finally, a total of 39 key lncRNAs were identified, which regulate crucial pathways in myocardial infarction. Through pathway analysis of these 39 key lncRNAs, the novel function of an annotated lncRNAs-H19 was predicted, which may regulate apoptosis signal-regulating kinase, which is a protein that promotes pathological cardiac remodeling following myocardial infarction. The results of the present study not only provide potential non-coding RNA biomarkers, but also provide further insights into understanding the molecular mechanism of lncRNAs.

Long noncoding RNAs in cardiac development and ageing

A large part of the mammalian genome is transcribed into noncoding RNAs. Long noncoding RNAs (lncRNAs) have emerged as critical epigenetic regulators of gene expression. Distinct molecular mechanisms allow lncRNAs either to activate or to repress gene expression, thereby participating in the regulation of cellular and tissue function. LncRNAs, therefore, have important roles in healthy and diseased hearts, and might be targets for therapeutic intervention. In this Review, we summarize the current knowledge of the roles of lncRNAs in cardiac development and ageing. After describing the definition and classification of lncRNAs, we present an overview of the mechanisms by which lncRNAs regulate gene expression. We discuss the multiple roles of lncRNAs in the heart, and focus on the regulation of embryonic stem cell differentiation, cardiac cell fate and development, and cardiac ageing. We emphasize the importance of chromatin remodelling in this regulation. Finally, we discuss the therapeutic and biomarker potential of lncRNAs.

microRNAs in Essential Hypertension and Blood Pressure Regulation

Unravelling the complete genetic predisposition to high blood pressure (BP) has proven to be challenging. This puzzle and the fact that coding regions of the genome account for less than 2 % of the entire human DNA support the hypothesis that mechanisms besides coding genes are likely to contribute to BP regulation. Non-coding RNAs, especially microRNAs, are emerging as key players of transcription regulation in both health and disease states. They control basic functions in virtually all cell types relevant to the cardiovascular system and, thus, a direct involvement with BP regulation is highly probable. Here we review the literature about microRNAs associated with regulation of BP and hypertension, highlighting investigations, methodology and difficulties arising in the field. These molecules are being studied for exploitation in diagnostics, prognostics and therapeutics in many diseases. There have been some studies that examined biological fluid microRNAs as biomarkers for hypertension, but most remain inconclusive due to the small sample sizes and differences in methodological standardisation. Fewer studies have analysed tissue microRNA levels in vascular smooth muscle cells and the kidney. Others focused on the interaction between single nucleotide polymorphisms and microRNA binding sites. Studies in animals have shown that angiotensin II, high-salt diet and exercise change microRNA levels in hypertension. Treatment of spontaneously hypertensive rats with a miR-22 inhibitor and treatment of hypertensive Schlager BPH/2J mice with a miR-181a mimic decreased their BP. This supports the use of microRNAs as therapeutic targets in hypertension, and future studies should test the use of other microRNAs found in human association studies. In conclusion, there is a clear need of increased pace of human, animal and functional studies to help us understand the multifaceted roles of microRNAs as critical regulators of the development and physiology of BP.

The emerging role of non-coding RNA in essential hypertension and blood pressure regulation

Unravelling the complete genetic predisposition to high blood pressure (BP) has proven to be challenging. This puzzle and the fact that coding regions of the genome account for less than 2% of the entire human DNA support the hypothesis that genetic mechanism besides coding genes are likely to contribute to BP regulation. Non-coding RNAs (ncRNAs) are emerging as key players of transcription regulation in both health and disease states. They control basic functions in virtually all cell types relevant to the cardiovascular system and, thus, a direct involvement with BP regulation is highly probable. Here, we review the literature about ncRNAs associated with human BP and essential hypertension, highlighting investigations, methodology and difficulties arising in the field. The most investigated ncRNAs so far are microRNAs (miRNAs), small ncRNAs that modulate gene expression by posttranscriptional mechanisms. We discuss studies that have examined miRNAs associated with BP in biological fluids, such as blood and urine, and tissues, such as vascular smooth muscle cells and the kidney. Furthermore, we review the interaction between miRNA binding sites and single nucleotide polymorphisms in genes associated with BP. In conclusion, there is a clear need for more human and functional studies to help elucidate the multifaceted roles of ncRNAs, in particular mid- and long ncRNAs in BP regulation.

Aging and cardiovascular diseases: the role of gene-diet interactions

In the study of longevity, increasing importance is being placed on the concept of healthy aging rather than considering the total number of years lived. Although the concept of healthy lifespan needs to be defined better, we know that cardiovascular diseases (CVDs) are the main age-related diseases. Thus, controlling risk factors will contribute to reducing their incidence, leading to healthy lifespan. CVDs are complex diseases influenced by numerous genetic and environmental factors. Numerous gene variants that are associated with a greater or lesser risk of the different types of CVD and of intermediate phenotypes (i.e., hypercholesterolemia, hypertension, diabetes) have been successfully identified. However, despite the close link between aging and CVD, studies analyzing the genes related to human longevity have not obtained consistent results and there has been little coincidence in the genes identified in both fields. The APOE gene stands out as an exception, given that it has been identified as being relevant in CVD and longevity. This review analyzes the genomic and epigenomic factors that may contribute to this, ranging from identifying longevity genes in model organisms to the importance of gene-diet interactions (outstanding among which is the case of the TCF7L2 gene).

Noncoding RNAs and myocardial fibrosis

Cardiac stress leads to remodelling of cardiac tissue, which often progresses to heart failure and death. Part of the remodelling process is the formation of fibrotic tissue, which is caused by exaggerated activity of cardiac fibroblasts leading to excessive extracellular matrix production within the myocardium. Noncoding RNAs (ncRNAs) are a diverse group of endogenous RNA-based molecules, which include short (∼22 nucleotides) microRNAs and long ncRNAs (of >200 nucleotides). These ncRNAs can regulate important functions in many cardiovascular cells types. This Review focuses on the role of ncRNAs in cardiac fibrosis; specifically, ncRNAs as therapeutic targets, factors for direct fibroblast transdifferentation, their use as diagnostic and prognostic markers, and their potential to function as paracrine modulators of cardiac fibrosis and remodelling.

Circulating small noncoding RNAs as biomarkers of aging

Small noncoding RNAs (sncRNAs) mediate a variety of cellular functions in animals and plants. Deep sequencing has made it possible to obtain highly detailed information on the types and abundance of sncRNAs in biological specimens, leading to the discovery that sncRNAs circulate in the blood of humans and mammals. The most abundant types of circulating sncRNAs are microRNAs (miRNAs), 5' transfer RNA (tRNA) halves, and YRNA fragments, with minute amounts of other types that may nevertheless be significant. Of the more abundant circulating sncRNAs only miRNAs have well described functions, but characteristics of the others suggest specific processing and secretion as complexes that protect the RNA from degradation. The properties of circulating sncRNAs are consistent with their serving as signaling molecules, and investigations of circulating miRNAs support the view that they can enter cells and regulate cellular functions. The serum levels of specific sncRNAs change markedly with age, and these changes can be mitigated by calorie restriction (CR), indicating that levels are under physiologic control. The ability of circulating sncRNAs to transmit functions between cells and to regulate a broad spectrum of cellular functions, and the changes in their levels with age, implicate them in the manifestations of aging. Our understanding of the functions of circulating sncRNA, particularly in relation to aging, is currently at a very early stage; results to date suggest that more extensive investigation will yield important insights into mechanisms of aging.

Long noncoding RNAs in patients with acute myocardial infarction

RATIONALE

Long noncoding RNAs (lncRNAs) constitute a novel class of noncoding RNAs that regulate gene expression. Although recent data suggest that lncRNAs may be associated with cardiac disease, little is known about lncRNAs in the setting of myocardial ischemia.

OBJECTIVE

To measure lncRNAs in patients with myocardial infarction (MI).

METHODS AND RESULTS

We enrolled 414 patients with acute MI treated by primary percutaneous coronary intervention. Blood samples were harvested at the time of reperfusion. Expression levels of 5 lncRNAs were measured in peripheral blood cells by quantitative polymerase chain reaction: hypoxia inducible factor 1A antisense RNA 2, cyclin-dependent kinase inhibitor 2B antisense RNA 1 (ANRIL), potassium voltage-gated channel, KQT-like subfamily, member 1 opposite strand/antisense transcript 1 (KCNQ1OT1), myocardial infarction-associated transcript, and metastasis-associated lung adenocarcinoma transcript 1. Levels of hypoxia inducible factor 1A antisense RNA 2, KCNQ1OT1, and metastasis-associated lung adenocarcinoma transcript 1 were higher in patients with MI than in healthy volunteers (P<0.01), and levels of ANRIL were lower in patients with MI (P=0.003). Patients with ST-segment-elevation MI had lower levels of ANRIL (P<0.001), KCNQ1OT1 (P<0.001), myocardial infarction-associated transcript (P<0.001), and metastasis-associated lung adenocarcinoma transcript 1 (P=0.005) when compared with patients with non-ST-segment-elevation MI. Levels of ANRIL were associated with age, diabetes mellitus, and hypertension. Patients presenting within 3 hours of chest pain onset had elevated levels of hypoxia inducible factor 1A antisense RNA 2 when compared with patients presenting later on. ANRIL, KCNQ1OT1, myocardial infarction-associated transcript, and metastasis-associated lung adenocarcinoma transcript 1 were significant univariable predictors of left ventricular dysfunction as assessed by an ejection fraction ≤40% at 4-month follow-up. In multivariable and reclassification analyses, ANRIL and KCNQ1OT1 improved the prediction of left ventricular dysfunction by a model, including demographic features, clinical parameters, and cardiac biomarkers.

CONCLUSIONS

Levels of lncRNAs in blood cells are regulated after MI and may help in prediction of outcome. This motivates further investigation of the role of lncRNAs after MI.