Long Noncoding RNA Kcna2 Antisense RNA Contributes to Ventricular Arrhythmias via Silencing Kcna2 in Rats With Congestive Heart Failure

Roles of KCNA2 in Neurological Diseases: from Physiology to Pathology

Potassium voltage-gated channel subfamily a member 2 (Kv1.2, encoded by KCNA2) is highly expressed in the central and peripheral nervous systems. Based on the patch clamp studies, gain-of function (GOF), loss-of-function (LOF), and a mixed type (GOF/LOF) variants can cause different conditions/disorders. KCNA2-related neurological diseases include epilepsy, intellectual disability (ID), attention deficit/hyperactive disorder (ADHD), autism spectrum disorder (ASD), pain as well as autoimmune and movement disorders. Currently, the molecular mechanisms for the reported variants in causing diverse disorders are unknown. Consequently, this review brings up to date the related information regarding the structure and function of Kv1.2 channel, expression patterns, neuronal localizations, and tetramerization as well as important cell and animal models. In addition, it provides updates on human genetic variants, genotype-phenotype correlations especially highlighting the deep insight into clinical prognosis of KCNA2-related developmental and epileptic encephalopathy, mechanisms, and the potential treatment targets for all KCNA2-related neurological disorders.

Out of the dark: the emerging roles of lncRNAs in pain

The dark genome, the nonprotein-coding part of the genome, is replete with long noncoding RNAs (lncRNAs). These functionally versatile transcripts, with specific temporal and spatial expression patterns, are critical gene regulators that play essential roles in health and disease. In recent years, FAAH-OUT was identified as the first lncRNA associated with an inherited human pain insensitivity disorder. Several other lncRNAs have also been studied for their contribution to chronic pain and genome-wide association studies are frequently identifying single nucleotide polymorphisms that map to lncRNAs. For a long time overlooked, lncRNAs are coming out of the dark and into the light as major players in human pain pathways and as potential targets for new RNA-based analgesic medicines.

lncRNA CDKN2B-AS1 is downregulated in patients with ventricular fibrillation in acute myocardial infarction

Ventricular fibrillation (VF) in acute myocardial infarction (AMI) is the main cause of deaths occurring in the acute phase of an ischemic event. Although it is known that genetics may play an important role in this pathology, the possible role of long non-coding RNAs (lncRNA) has never been studied. Therefore, the aim of this work is to study the expression of 10 lncRNAs in patients with and without VF in AMI. For this purpose, the expression of CDKN2B-AS1, KCNQ1OT1, LIPCAR, MALAT1, MIAT, NEAT1, SLC16A1-AS1, lnc-TK2-4:2, TNFRSF14-AS1, and UCA1 were analyzed. After the analysis and Bonferroni correction, the lncRNA CDKN2B-AS showed a statistical significance lower expression (P values of 2.514 x 10-5). In silico analysis revealed that six proteins could be related to the possible effect of lncRNA CDKN2B-AS1: AGO3, PLD4, POU4F1, ZNF26, ZNF326 and ZNF431. These in silico proteins predicted to have a low cardiac expression, although there is no literature indicating a potential relationship with VF in AMI. Thus, the lncRNA CDKN2B-AS1 shows a significant lower expression in patients with VF in AMI vs patients without VF in AMI. Literature data suggest that the role of CDKN2B1-AS is related to the miR-181a/SIRT1 pathway.

GAS5 silencing attenuates hypoxia-induced cardiomyocytes injury by targeting miR-21/PTEN

INTRODUCTION

Myocardial hypoxia is an important factor causing myocardial infarction (MI). Interestingly, many unknown factors in the molecular mechanism of MI remain unclear. Our study explored the role of lncRNA growth arrest-specific 5 (GAS5) in cell injury under hypoxia.

METHODS

AS5 expression was assessed in MI and human cardiomyocytes under hypoxia through RT-qPCR assay. Methyl thiazolyl tetrazolium assay, flow cytometry assay, and transwell assay was carried out for cell viability, cell apoptosis, cell migration, and invasion, respectively. The regulatory target of GAS5 was explored through a dual-luciferase reporter assay.

RESULTS

Our findings indicated that the upregulation of GAS5 was related to hypoxia. Downregulation of GAS5 expression could decrease hypoxia-induced cell apoptosis and increase cell migration and invasion. Moreover, GAS 5 targeted miR-21, which regulated the phosphatase and tension homology deleted on chromosome ten gene (PTEN) expression. Furthermore, the knockdown of miR-21 eliminated the effect of GAS5 silencing on cell injury.

CONCLUSION

These results indicated that lncRNA GAS5 silencing decreased cardiomyocyte injury by hypoxia-induced through regulating miR-21/PTEN.

Identification of long non-coding RNA in formaldehyde-induced cardiac dysplasia in rats

Formaldehyde exposure during pregnancy can cause fetal congenital heart disease (CHD). However, the regulatory mechanism remains unclear. Studies on the biology of long non-coding RNAs (lncRNAs) show that lncRNAs can influence cardiac development and disease. However, expression patterns and regulatory mechanisms of action of lncRNAs in formaldehyde-induced CHD remain unclear. We used high-throughput sequencing strategies as a means of identifying lncRNA expression profiles in heart tissues of normal and formaldehyde-exposed newborn rats. Overall, 763 differentially expressed lncRNAs were identified, including 325 and 438 that were respectively up-regulated and down-regulated. GO and KEGG analyses indicated that the Ras and hedgehog signaling pathways may be important regulatory pathways in CHD caused by exposure to formaldehyde. A lncRNA-miRNA-mRNA co-expression network was constructed and a key miRNA, rno-miR-665, was identified. Furthermore, qRT-PCR analysis verified that the novel lncRNAs: MSTRG.27313.2, MSTRG.30629.2, MSTRG.36520.33, MSTRG.91234.1, and MSTRG.91233.9, were upregulated in the formaldehyde-exposed group. These differentially expressed lncRNAs identified during formaldehyde-induced CHD in newborn rats help explain CHD pathogenesis and provide an effective reference for diagnosing and treating CHD.

Circulatory long noncoding RNAs (circulatory-LNC-RNAs) as novel biomarkers and therapeutic targets in cardiovascular diseases: Implications for cardiovascular diseases complications

Cardiovascular diseases (CVDs) are a group of disorders with major global health consequences. The prevalence of CVDs continues to grow due to population-aging and lifestyle modifications. Non-coding RNAs (ncRNAs) as key regulators of cell signaling pathways have gained attention in the occurrence and development of CVDs. Exosomal-lncRNAs (exos-lncRNAs) are emerging biomarkers due to their high sensitivity and specificity, stability, accuracy and accessibility in the biological fluids. Recently, circulatory and exos-based-lncRNAs are emerging and novel bio-tools in various pathogenic conditions. It is worth mentioning that dysregulation of these molecules has been found in different types of CVDs. In this regard, we aimed to discuss the knowledge gaps and suggest research priorities regarding circulatory and exos-lncRNAs as novel bio-tools and therapeutic targets for CVDs.

Regulation by noncoding RNAs of local translation, injury responses, and pain in the peripheral nervous system

Neuropathic pain is a chronic condition arising from damage to somatosensory pathways that results in pathological hypersensitivity. Persistent pain can be viewed as a consequence of maladaptive plasticity which, like most enduring forms of cellular plasticity, requires altered expression of specific gene programs. Control of gene expression at the level of protein synthesis is broadly utilized to directly modulate changes in activity and responsiveness in nociceptive pathways and provides an effective mechanism for compartmentalized regulation of the proteome in peripheral nerves through local translation. Levels of noncoding RNAs (ncRNAs) are commonly impacted by peripheral nerve injury leading to persistent pain. NcRNAs exert spatiotemporal regulation of local proteomes and affect signaling cascades supporting altered sensory responses that contribute to hyperalgesia. This review discusses ncRNAs found in the peripheral nervous system (PNS) that are dysregulated following nerve injury and the current understanding of their roles in pathophysiological pain-related responses including neuroimmune interactions, neuronal survival and axon regeneration, Schwann cell dedifferentiation and proliferation, intercellular communication, and the generation of ectopic action potentials in primary afferents. We review progress in the field beyond cataloging, with a focus on the relevant target transcripts and mechanisms underlying pain modulation by ncRNAs.

Long non-coding RNAs in the pathogenesis of heart failure: A literature review

Heart failure (HF) is a common cardiovascular disorder and a major cause of mortality and morbidity in older people. The mechanisms underlying HF are still not fully understood, restricting novel therapeutic target discovery and drug development. Besides, few drugs have been shown to improve the survival of HF patients. Increasing evidence suggests that long non-coding RNAs (lncRNAs) serve as a critical regulator of cardiac physiological and pathological processes, regarded as a new target of treatment for HF. lncRNAs are versatile players in the pathogenesis of HF. They can interact with chromatin, protein, RNA, or DNA, thereby modulating chromatin accessibility, gene expressions, and signaling transduction. In this review, we summarized the current knowledge on how lncRNAs involve in HF and categorized them into four aspects based on their biological functions, namely, cardiomyocyte contractility, cardiac hypertrophy, cardiac apoptosis, and myocardial fibrosis. Along with the extensive laboratory data, RNA-based therapeutics achieved great advances in recent years. These indicate that targeting lncRNAs in the treatment of HF may provide new strategies and address the unmet clinical needs.

Genomic and Non-Genomic Regulatory Mechanisms of the Cardiac Sodium Channel in Cardiac Arrhythmias

Nav1.5 is the predominant cardiac sodium channel subtype, encoded by the SCN5A gene, which is involved in the initiation and conduction of action potentials throughout the heart. Along its biosynthesis process, Nav1.5 undergoes strict genomic and non-genomic regulatory and quality control steps that allow only newly synthesized channels to reach their final membrane destination and carry out their electrophysiological role. These regulatory pathways are ensured by distinct interacting proteins that accompany the nascent Nav1.5 protein along with different subcellular organelles. Defects on a large number of these pathways have a tremendous impact on Nav1.5 functionality and are thus intimately linked to cardiac arrhythmias. In the present review, we provide current state-of-the-art information on the molecular events that regulate SCN5A/Nav1.5 and the cardiac channelopathies associated with defects in these pathways.

Multidimensional Mechanistic Spectrum of Long Non-coding RNAs in Heart Development and Disease

With the large-scale genome-wide sequencing, long non-coding RNAs (lncRNAs) have been found to compose of a large portion of the human transcriptome. Recent studies demonstrated the multidimensional functions of lncRNAs in heart development and disease. The subcellular localization of lncRNA is considered as a key factor that determines lncRNA function. Cytosolic lncRNAs mainly regulate mRNA stability, mRNA translation, miRNA processing and function, whereas nuclear lncRNAs epigenetically regulate chromatin remodeling, structure, and gene transcription. In this review, we summarize the molecular mechanisms of cytosolic and nuclear lncRNAs in heart development and disease separately, and emphasize the recent progress to dictate the crosstalk of cytosolic and nuclear lncRNAs in orchestrating the same biological process. Given the low evolutionary conservation of most lncRNAs, deeper understanding of human lncRNA will uncover a new layer of human regulatory mechanism underlying heart development and disease, and benefit the future clinical treatment for human heart disease.

4-Aminopyridine is a promising treatment option for patients with gain-of-function KCNA2-encephalopathy

[Figure: see text].

Pathological Bases and Clinical Application of Long Noncoding RNAs in Cardiovascular Diseases

Increasing evidence has suggested that noncoding RNAs (ncRNAs) have vital roles in cardiovascular tissue homeostasis and diseases. As a main subgroup of ncRNAs, long ncRNAs (lncRNAs) have been reported to play important roles in lipid metabolism, inflammation, vascular injury, and angiogenesis. They have also been implicated in many human diseases including atherosclerosis, arterial remodeling, hypertension, myocardial injury, cardiac remodeling, and heart failure. Importantly, it was reported that lncRNAs were dysregulated in the development and progression of cardiovascular diseases (CVDs). A variety of studies have demonstrated that lncRNAs could influence gene expression at transcription, post-transcription, translation, and post-translation level. Particularly, emerging evidence has confirmed that the crosstalk among lncRNAs, mRNA, and miRNAs is an important underlying regulatory mechanism of lncRNAs. Nevertheless, the biological functions and molecular mechanisms of lncRNAs in CVDs have not been fully explored yet. In this review, we will comprehensively summarize the main findings about lncRNAs and CVDs, highlighting the most recent discoveries in the field of lncRNAs and their pathophysiological functions in CVDs, with the aim of dissecting the intrinsic association between lncRNAs and common risk factors of CVDs including hypertension, high glucose, and high fat. Finally, the potential of lncRNAs functioning as the biomarkers, therapeutic targets, as well as specific diagnostic and prognostic indicators of CVDs will be discussed in this review.

Investigation of candidate genes and mechanisms underlying obesity associated type 2 diabetes mellitus using bioinformatics analysis and screening of small drug molecules

BACKGROUND

Obesity associated type 2 diabetes mellitus is a metabolic disorder ; however, the etiology of obesity associated type 2 diabetes mellitus remains largely unknown. There is an urgent need to further broaden the understanding of the molecular mechanism associated in obesity associated type 2 diabetes mellitus.

METHODS

To screen the differentially expressed genes (DEGs) that might play essential roles in obesity associated type 2 diabetes mellitus, the publicly available expression profiling by high throughput sequencing data (GSE143319) was downloaded and screened for DEGs. Then, Gene Ontology (GO) and REACTOME pathway enrichment analysis were performed. The protein - protein interaction network, miRNA - target genes regulatory network and TF-target gene regulatory network were constructed and analyzed for identification of hub and target genes. The hub genes were validated by receiver operating characteristic (ROC) curve analysis and RT- PCR analysis. Finally, a molecular docking study was performed on over expressed proteins to predict the target small drug molecules.

RESULTS

A total of 820 DEGs were identified between healthy obese and metabolically unhealthy obese, among 409 up regulated and 411 down regulated genes. The GO enrichment analysis results showed that these DEGs were significantly enriched in ion transmembrane transport, intrinsic component of plasma membrane, transferase activity, transferring phosphorus-containing groups, cell adhesion, integral component of plasma membrane and signaling receptor binding, whereas, the REACTOME pathway enrichment analysis results showed that these DEGs were significantly enriched in integration of energy metabolism and extracellular matrix organization. The hub genes CEBPD, TP73, ESR2, TAB1, MAP 3K5, FN1, UBD, RUNX1, PIK3R2 and TNF, which might play an essential role in obesity associated type 2 diabetes mellitus was further screened.

CONCLUSIONS

The present study could deepen the understanding of the molecular mechanism of obesity associated type 2 diabetes mellitus, which could be useful in developing therapeutic targets for obesity associated type 2 diabetes mellitus.

LncRNAs in Cardiomyocyte Maturation: New Window for Cardiac Regenerative Medicine

Cardiomyocyte (CM) maturation, which is characterized by structural, functional, and metabolic specializations, is the last phase of CM development that prepares the cells for efficient and forceful contraction throughout life. Over the past decades, CM maturation has gained increased attention due to the fact that pluripotent stem cell-derived CMs are structurally, transcriptionally, and functionally immature and embryonic-like, which causes a defect in cell replacement therapy. The current challenge is to discover and understand the molecular mechanisms, which control the CM maturation process. Currently, emerging shreds of evidence emphasize the role of long noncoding RNAs (lncRNAs) in regulating different aspects of CM maturation, including myofibril maturation, electrophysiology, and Ca²⁺ handling maturation, metabolic maturation and proliferation to hypertrophy transition. Here, we describe the structural and functional characteristics of mature CMs. Furthermore, this review highlights the lncRNAs as crucial regulators of different aspects in CM maturation, which have the potential to be used for mature CM production. With the current advances in oligonucleotide delivery; lncRNAs may serve as putative therapeutic targets to produce highly mature CMs for research and regenerative medicine.

Long noncoding RNA NONHSAT177112.1 aggravates inflammation and apoptosis in LPS-treated human cardiomyocytes

Aim: To explore the roles of lncRNA NONHSAT177112.1 in the inflammatory injury of human cardiomyocytes (HCMs) induced by lipopolysaccharide (LPS). Materials & methods: The sublocalization of NONHSAT177112.1 was detected by FISH. HCMs were stimulated with LPS to induce inflammatory injury. NONHSAT177112.1 expression was detected by quantitative real-time PCR. Cell apoptosis and viability were detected by flow cytometry and CCK-8 assays. The expression of inflammatory cytokines and myocardial enzymes were detected by PCR and ELISA. Results: NONHSAT177112.1 is expressed in the nucleus and cytoplasm. NONHSAT177112.1 showed dynamic expression that first increased and then decreased during LPS stimulation. NONHSAT177112.1 knockdown reversed the promotion effect of LPS on inflammatory injury. Conversely, NONHSAT177112.1 overexpression exerted the opposite effects. Conclusion: NONHSAT177112.1 aggravates inflammatory injury in LPS-treated HCMs.

Long noncoding RNA SNHG14 regulates ox-LDL-induced atherosclerosis cell proliferation and apoptosis by targeting miR-186-5p/WIPF2 axis

To investigate the role of small nucleolus RNA host gene 14 (SNHG14) in the progression of atherosclerosis (AS), bioinformatics analysis, and other relevant experiments (cell counting kit-8, flow cytometry, quantitative real-time polymerase chain reaction, luciferase reporter, RNA immunoprecipitation, RNA pull-down, and western blot assays) were done. The current study revealed that SNHG14 level was high in the serum of AS patients and oxidized low-density lipoprotein (ox-LDL)-induced AS cell lines. Besides, we found that SNHG14 accelerated cell proliferation while inhibited cell apoptosis in ox-LDL-induced AS cell lines. Next, SNHG14 was confirmed to be a sponge for miR-186-5p in AS cells, and it was validated that SNHG14 regulated AS cell proliferation and apoptosis by sponging miR-186-5p. Moreover, we uncovered that WAS-interacting protein family member 2 (WIPF2) was a downstream target of miR-186-5p in AS cells. Finally, it was demonstrated that miR-186-5p modulated AS cell proliferation and apoptosis via targeting WIPF2. To conclude, our research disclosed that SNHG14 affected ox-LDL-induced AS cell proliferation and apoptosis through miR-186-5p/WIPF2 axis, which may provide a theoretical basis for the treatment and diagnosis of AS.

Strategies and technologies for exploring long noncoding RNAs in heart failure

Long non-coding RNA (lncRNA) was once considered to be the "noise" of genome transcription without biological function. However, increasing evidence shows that lncRNA is dynamically expressed in developmental stage or disease status, playing a regulatory role in the process of gene expression and translation. In recent years, lncRNA is considered to be a core node of functional regulatory networks that controls cardiac and also involves in multiple process of heart failure such as myocardial hypertrophy, fibrosis, angiogenesis, etc., which would be a therapeutic target for diseases. In fact, it is the development of technology that has improved our understanding of lncRNAs and broadened our perspective on heart failure. From transcriptional "noise" to star molecule, progress of lncRNAs can't be achieved without the combination of multidisciplinary technologies, especially the emergence of high-throughput approach. Thus, here, we review the strategies and technologies available for the exploration lncRNAs and try to yield insights into the prospect of lncRNAs in clinical diagnosis and treatment in heart failure.

Long Non-Coding RNAs in Atrial Fibrillation: Pluripotent Stem Cell-Derived Cardiomyocytes as a Model System

Atrial fibrillation (AF) is a type of sustained arrhythmia in humans often characterized by devastating alterations to the cardiac conduction system as well as the structure of the atria. AF can lead to decreased cardiac function, heart failure, and other complications. Long non-coding RNAs (lncRNAs) have been shown to play important roles in the cardiovascular system, including AF; however, a large group of lncRNAs is not conserved between mouse and human. Furthermore, AF has complex networks showing variations in mechanisms in different species, making it challenging to utilize conventional animal models to investigate the functional roles and potential therapeutic benefits of lncRNAs for AF. Fortunately, pluripotent stem cell (PSC)-derived cardiomyocytes (CMs) offer a reliable platform to study lncRNA functions in AF because of certain electrophysiological and molecular similarities with native human CMs. In this review, we first summarize the broad aspects of lncRNAs in various heart disease settings, then focus on their potential roles in AF development and pathophysiology. We also discuss current uses of PSCs in AF research and describe how these studies could be developed into novel therapeutics for AF and other cardiovascular diseases.

Epigenetic Regulation of Alternative mRNA Splicing in Dilated Cardiomyopathy

In recent years, the genetic architecture of dilated cardiomyopathy (DCM) has been more thoroughly elucidated. However, there is still insufficient knowledge on the modifiers and regulatory principles that lead to the failure of myocardial function. The current study investigates the association of epigenome-wide DNA methylation and alternative splicing, both of which are important regulatory principles in DCM. We analyzed screening and replication cohorts of cases and controls and identified distinct transcriptomic patterns in the myocardium that differ significantly, and we identified a strong association of intronic DNA methylation and flanking exons usage (p < 2 × 10^-16). By combining differential exon usage (DEU) and differential methylation regions (DMR), we found a significant change of regulation in important sarcomeric and other DCM-associated pathways. Interestingly, inverse regulation of Titin antisense non-coding RNA transcript splicing and DNA methylation of a locus reciprocal to TTN substantiate these findings and indicate an additional role for non-protein-coding transcripts. In summary, this study highlights for the first time the close interrelationship between genetic imprinting by DNA methylation and the transport of this epigenetic information towards the dynamic mRNA splicing landscape. This expands our knowledge of the genome-environment interaction in DCM besides simple gene expression regulation.

Expedition to the missing link: Long noncoding RNAs in cardiovascular diseases

With the advances in deep sequencing-based transcriptome profiling technology, it is now known that human genome is transcribed more pervasively than previously thought. Up to 90% of the human DNA is transcribed, and a large proportion of the human genome is transcribed as long noncoding RNAs (lncRNAs), a heterogenous group of non-coding transcripts longer than 200 nucleotides. Emerging evidence suggests that lncRNAs are functional and contribute to the complex regulatory networks involved in cardiovascular development and diseases. In this article, we will review recent evidence on the roles of lncRNAs in the biological processes of cardiovascular development and disorders. The potential applications of lncRNAs as biomarkers and targets for therapeutics are also discussed.

CYP2J2 Modulates Diverse Transcriptional Programs in Adult Human Cardiomyocytes

CYP2J2, a member of the Cytochrome P450 family of enzymes, is the most abundant epoxygenase in the heart and has multifunctional properties including bioactivation of arachidonic acid to epoxyeicosatrienoic acids, which, in turn, have been implicated in mediating several cardiovascular conditions. Using a proteomic approach, we found that CYP2J2 expression is lower in cardiac tissue from patients with cardiomyopathy compared to controls. In order to better elucidate the complex role played by CYP2J2 in cardiac cells, we performed targeted silencing of CYP2J2 expression in human adult ventricular cardiomyocytes and interrogated whole genome transcriptional responses. We found that knockdown of CYP2J2 elicits widespread alterations in gene expression of ventricular cardiomyocytes and leads to the activation of a diverse repertoire of programs, including those involved in ion channel signaling, development, extracellular matrix, and metabolism. Several members of the differentially up-regulated ion channel module have well-known pathogenetic roles in cardiac dysrhythmias. By leveraging causal network and upstream regulator analysis, we identified several candidate drivers of the observed transcriptional response to CYP2J2 silencing; these master regulators have been implicated in aberrant cardiac remodeling, heart failure, and myocyte injury and repair. Collectively, our study demonstrates that CYP2J2 plays a central and multifaceted role in cardiomyocyte homeostasis and provides a framework for identifying critical regulators and pathways influenced by this gene in cardiovascular health and disease.

Non-coding RNAs and Cardiac Arrhythmias

Cardiac arrhythmias represent wide and heterogenic group of disturbances in the cardiac rhythm. Pathophysiology of individual arrhythmias is highly complex and dysfunction in ion channels/currents involved in generation or spreading of action potential is usually documented. Non-coding RNAs (ncRNAs) represent highly variable group of molecules regulating the heart expression program, including regulation of the expression of individual ion channels and intercellular connection proteins, e.g. connexins.Within this chapter, we will describe basic electrophysiological properties of the myocardium. We will focus on action potential generation and spreading in pacemaker and non-pacemaker cells, including description of individual ion channels (natrium, potassium and calcium) and their ncRNA-mediated regulation. Most of the studies have so far focused on microRNAs, thus, their regulatory function will be described into greater detail. Clinical consequences of altered ncRNA regulatory function will also be described together with potential future directions of the research in the field.

Sirt1 Antisense Long Noncoding RNA Promotes Cardiomyocyte Proliferation by Enhancing the Stability of Sirt1

Background

Antisense long noncoding RNAs (lncRNAs) are single‐stranded RNAs that overlapped gene‐coding regions on the opposite DNA strand and play as critical regulators in cardiovascular diseases. The high conservation and stability may be good advantages for antisense lncRNAs. However, the roles of antisense lncRNAs in cardiomyocyte proliferation and cardiac regeneration are still unknown.

Methods and Results

In this study, we found that Silent information regulator factor 2 related enzyme 1 (Sirt1) antisense lncRNA expression was significantly increased during heart development. By gain and loss function of Sirt1 antisense lncRNA using adenovirus and locked nucleic acid, respectively, we demonstrated that Sirt1 antisense lncRNA promoted cardiomyocyte proliferation in vitro and in vivo, and the suppression of Sirt1 antisense lncRNA inhibited cardiomyocyte proliferation. Moreover, overexpression of Sirt1 antisense lncRNA enhanced cardiomyocyte proliferation, attenuated cardiomyocyte apoptosis, improved cardiac function, and decreased mortality rate after myocardial infarction. Furthermore, Sirt1 antisense lncRNA can bind the Sirt1 3′‐untranslated region, enhancing the stability of Sirt1 and increasing Sirt1 abundance at both the mRNA and protein levels. Finally, we found that Sirt1 was involved in Sirt1 antisense lncRNA‐induced cardiomyocyte proliferation.

Conclusions

The present study identified Sirt1 antisense lncRNA as a novel regulator of cardiomyocyte proliferation and cardiac regeneration by interacting and stabilizing Sirt1 mRNA, which may serve as an effective gene target for preventing myocardial infarction.

Clinical value of non-coding RNAs in cardiovascular, pulmonary, and muscle diseases

Although a majority of the mammalian genome is transcribed to RNA, mounting evidence indicates that only a minor proportion of these transcriptional products are actually translated into proteins. Since the discovery of the first non-coding RNA (ncRNA) in the 1980s, the field has gone on to recognize ncRNAs as important molecular regulators of RNA activity and protein function, knowledge of which has stimulated the expansion of a scientific field that quests to understand the role of ncRNAs in cellular physiology, tissue homeostasis, and human disease. Although our knowledge of these molecules has significantly improved over the years, we have limited understanding of their precise functions, protein interacting partners, and tissue-specific activities. Adding to this complexity, it remains unknown exactly how many ncRNAs there are in existence. The increased use of high-throughput transcriptomics techniques has rapidly expanded the list of ncRNAs, which now includes classical ncRNAs (e.g., ribosomal RNAs and transfer RNAs), microRNAs, and long ncRNAs. In addition, splicing by-products of protein-coding genes and ncRNAs, so-called circular RNAs, are now being investigated. Because there is substantial heterogeneity in the functions of ncRNAs, we have summarized the present state of knowledge regarding the functions of ncRNAs in heart, lungs, and skeletal muscle. This review highlights the pathophysiologic relevance of these ncRNAs in the context of human cardiovascular, pulmonary, and muscle diseases.

Silence of LncRNA GAS5 Protects Cardiomyocytes H9c2 against Hypoxic Injury via Sponging miR-142-5p

The regulatory role of long noncoding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) in both cancerous and noncancerous cells have been widely reported. This study aimed to evaluate the role of lncRNA GAS5 in heart failure caused by myocardial infarction. We reported that silence of lncRNA GAS5 attenuated hypoxia-triggered cell death, as cell viability was increased and apoptosis rate was decreased. This phenomenon was coupled with the down-regulated expression of p53, Bax and cleaved caspase-3, as well as the up-regulated expression of CyclinD1, CDK4 and Bcl-2. At the meantime, the expression of four heart failure-related miRNAs was altered when lncRNA GAS5 was silenced (miR-21 and miR-142-5p were up-regulated; miR-30b and miR-93 were down-regulated). RNA immunoprecipitation assay results showed that lncRNA GAS5 worked as a molecular sponge for miR-142-5p. More interestingly, the protective actions of lncRNA GAS5 silence on hypoxia-stimulated cells were attenuated by miR-142-5p suppression. Besides, TP53INP1 was a target gene for miR-142-5p. Silence of lncRNA GAS5 promoted the activation of PI3K/AKT and MEK/ERK signaling pathways in a miR-142-5p-dependent manner. Collectively, this study demonstrated that silence of lncRNA GAS5 protected H9c2 cells against hypoxia-induced injury possibly via sponging miR-142-5p, functionally releasing TP53INP1 mRNA transcripts that are normally targeted by miR-142-5p.

A novel long noncoding RNA FAF inhibits apoptosis via upregulating FGF9 through PI3K/AKT signaling pathway in ischemia-hypoxia cardiomyocytes

Long noncoding RNAs (lncRNAs) have been increasingly considered to play an important role in the pathological process of various cardiovascular diseases, which often bind to the proximal promoters of the protein-coding gene to regulate the protein expression. However, the functions and mechanisms of lncRNAs in cardiomyocytes have not been fully elucidated. High-throughput RNA sequencing was performed to identify the differently expressed lncRNAs and messenger RNAs (mRNAs) between acute myocardial infarction (AMI) rats and healthy controls. One novel lncRNA FGF9-associated factor (termed FAF) and mRNAs in AMI rats were verified by bioinformatics, real-time polymerase chain reaction or western blot. Moreover, RNA fluorescence in situ hybridization was performed to determine the location of lncRNA. Subsequently, a series of in vitro assays were used to observe the functions of lncRNA FAF in cardiomyocytes. The expression of lncRNA FAF and FGF9 were remarkably decreased in ischemia-hypoxia cardiomyocytes and heart tissues of AMI rats. Overexpression of FAF could significantly inhibit cardiomyocytes apoptosis induced by ischemia and hypoxia. Conversely, knockdown of lncRNA FAF could promote apoptosis in ischemia-hypoxia cardiomyocytes. Moreover, overexpression of lncRNA FAF could also increase the expression of FGF9. Knockdown of the FGF9 expression could promote apoptosis in cardiomyocytes with the insult of ischemia and hypoxia, which was consistent with the effect of lncRNA FAF overexpression on cardiomyocyte apoptosis. Mechanistically, FGF9 inhibited cardiomyocytes apoptosis through activating signaling tyrosine kinase FGFR2 via phosphoinositide 3-kinase/protein kinase B signaling pathway. Thus, lncRNA FAF plays a protective role in ischemia-hypoxia cardiomyocytes and may serve as a treatment target for AMI.

Identification of functional lncRNAs in atrial fibrillation by integrative analysis of the lncRNA-mRNA network based on competing endogenous RNAs hypothesis

A mounting body of evidence has suggested that long noncoding RNAs (lncRNAs) play critical roles in human diseases by acting as competing endogenous RNAs (ceRNAs). However, the functions and ceRNA mechanisms of lncRNAs in atrial fibrillation (AF) remain to date unclear. In this study, we constructed an AF-related lncRNA-mRNA network (AFLMN) based on ceRNA theory, by integrating probe reannotation pipeline and microRNA (miRNA)-target regulatory interactions. Two lncRNAs with central topological properties in the AFLMN were first obtained. By using bidirectional hierarchical clustering, we identified two modules containing four lncRNAs, which were significantly enriched in many known pathways of AF. To elucidate the ceRNA interactions in certain disease or normal condition, the dysregulated lncRNA-mRNA crosstalks in AF were further analyzed, and six hub lncRNAs were obtained from the network. Furthermore, random walk analysis of the AFLMN suggested that lncRNA RP11-296O14.3 may function importantly in the pathological process of AF. All these eight lncRNAs that were identified from previous steps (RP11-363E7.4, GAS5, RP11-410L14.2, HAGLR, RP11-421L21.3, RP11-111K18.2, HOTAIRM1, and RP11-296O14.3) exhibited a strong diagnostic power for AF. The results of our study provide new insights into the functional roles and regulatory mechanisms of lncRNAs in AF, and facilitate the discovery of novel diagnostic biomarkers or therapeutic targets.