Long noncoding RNA MALAT1 mediates cardiac fibrosis in experimental postinfarct myocardium mice model

Current concepts in the epigenetic regulation of cardiac fibrosis

Cardiac fibrosis is a significant driver of congestive heart failure, a syndrome that continues to affect a growing patient population globally. Cardiac fibrosis results from a constellation of complex processes at the transcription, receptor, and signaling axes levels. Various mediators and signaling cascades, such as the transformation growth factor-beta pathway, have been implicated in the pathophysiology of cardiac tissue fibrosis. Our understanding of these markers and pathways has improved in recent years as more advanced technologies and assays have been developed, allowing for better delineation of the crosstalk between specific factors. There is mounting evidence suggesting that epigenetic modulation plays a pivotal role in the progression of cardiac fibrosis. Transcriptional regulation of key pro- and antifibrotic pathways can accentuate or blunt the rate and extent of fibrosis at the tissue level. Exosomes, micro-RNAs, and long noncoding RNAs all belong to factors that can impact the epigenetic signature in cardiac fibrosis. Herein, we comprehensively review the latest literature about exosomes, their contents, and cardiac fibrosis. In doing so, we highlight the specific transcriptional factors with pro- or antifibrotic properties. We also assimilate the data supporting these mediators' potential utility as diagnostic or prognostic biomarkers. Finally, we offer insight into where further work can be done to fill existing gaps to translate preclinical findings better and improve clinical outcomes.

LncRNA MALAT1 Knockdown Alleviates Fibrogenic Response in Human Endometrial Stromal Cells Via the miR-22-3p/TGFβR1/Smad2/3 Pathway

Intrauterine adhesion (IUA) resulting from irreversible fibrotic repair of endometrium is the main cause of secondary infertility in women, and current therapeutic approaches to IUA are limited. Increasing evidence has suggested the important role of competitive endogenous RNA (ceRNA) in IUA pathologies. This study aimed to investigate the long noncoding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1)-associated ceRNA in IUA development. We harvested endometrial tissues from patients with or without IUA and extracted endometrial stromal cells (ESCs) from normal endometrial tissues. Transforming growth factor β1 (TGF-β1) was used to induce fibrosis in ESCs. The expression of transforming growth factor β receptor 1 (TGFβR1), α-smooth muscle actin, phosphorylated suppressor of mother against decapentaplegic (p-Smad)2/3, collagen type I alpha 1, MALAT1, and microRNA (miR)-22-3p in endometrial tissues and ESCs was measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) or western blotting. Pearson's correlation analysis was conducted to assess the correlation between miR-22-3p expression or TGFβR1 and MALAT1 expression in endometrial tissues. The expression of TGFβR1 in ESCs was also evaluated by immunofluorescence staining. The location of MALAT1 was examined by fluorescence in situ hybridization. Luciferase reporter assays were performed to verify the binding relationship between MALAT1 or TGFβR1 and miR-22-3p. Cell viability was assessed via cell counting kit-8 assays. Our findings revealed that lncRNA MALAT1 and TGFβR1 were upregulated while miR-22-3p was downregulated in IUA endometrial tissues or TGF-β1-stimulated ESCs, and lncRNA MALAT1 expression was negatively correlated with miR-22-3p expression while being positively correlated with TGFβR1 expression in IUA endometrial tissues. Additionally, lncRNA MALAT1 was mainly located in the cytoplasm of ESCs and directly targeted miR-22-3p to regulate TGFβR1 expression. Moreover, knockdown of lncRNA MALAT1 exerted anti-fibrotic effects on ESCs by targeting miR-22-3p, and miR-22-3p overexpression inhibited the fibrosis of ESCs by binding to TGFβR1 3'untranslated region. Collectively, lncRNA MALAT1 promotes endometrial fibrosis by sponging miR-22-3p to regulate TGFβR1 and Smad2/3, and inhibition of MALAT1 may represent a promising therapeutic option for suppressing endometrial fibrosis.

Long noncoding RNA MALAT1 as a ceRNA drives mouse fibroblast activation via the miR-335-3p/P2ry2 axis

Fibrosis is a complex pathological process that can lead to the permanent loss of biological function, with P2ry2 playing a crucial role in this process. Long non-coding RNAs (lncRNAs) have been reported to play an critically important role in the fibrotic process. However, it remains unclear whether lncRNAs can regulate fibrosis through P2ry2. In this study, we detected the expression of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1). We investigated the expression patterns of lnc-MALAT1 and P2ry2 in denervated skeletal muscle, a classical model of fibrosis. Additionally, we utilized a TGF-β-mediated fibrosis model in NIH/3T3 cells to examine the effects of lnc-MALAT1 and P2ry2 on fibroblast activation and the underlying regulatory mechanisms in vitro. Our results demonstrated that the expression levels of lnc-MALAT1 and P2ry2 were consistently elevated in denervated skeletal muscle, correlating with the degree of fibrosis. In vitro experiments confirmed the regulatory effect of lnc-MALAT1 on P2ry2. Furthermore, we identified miR-335-3p as a potential key molecule in the regulatory relationship of lnc-MALAT1/P2ry2. Dual luciferase reporter assays and AGO2-RIP verified the molecular sponging effect of lnc-MALAT1 on miR-335-3p. Additionally, we validated the regulation of the lnc-MALAT1/miR-335-3p/P2ry2 axis through experimental approaches. In conclusion, our study identified a crucial role of lnc-MALAT1/miR-335-3p/P2ry2 axis in fibroblast activation, providing a promising treatment option against the fibrosis.

Unveiling the role of long non-coding RNA MALAT1: a comprehensive review on myocardial infarction

Myocardial infarction (MI) stands at top global causes of death in developed countries, owing mostly to atherosclerotic plaque growth and endothelial injury-induced reduction in coronary blood flow. While early reperfusion techniques have improved outcomes, long-term treatment continues to be difficult. The function of lncRNAs extends to regulating gene expression in various conditions, both physiological and pathological, such as cardiovascular diseases. The objective of this research is to extensively evaluate the significance of the lncRNA called Metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in the development and management of MI. According to research, MALAT1 is implicated in processes such as autophagy, apoptosis, cell proliferation, and inflammation in the cardiovascular system. This investigation examines recent research examining the effects of MALAT1 on heart function and its potential as a mean of diagnosis and treatment for post- MI complications and ischemic reperfusion injury.

Long Noncoding RNA MALAT1: Salt-Sensitive Hypertension

Hypertension stands as the leading global cause of mortality, affecting one billion individuals and serving as a crucial risk indicator for cardiovascular morbidity and mortality. Elevated salt intake triggers inflammation and hypertension by activating antigen-presenting cells (APCs). We found that one of the primary reasons behind this pro-inflammatory response is the epithelial sodium channel (ENaC), responsible for transporting sodium ions into APCs and the activation of NADPH oxidase, leading to increased oxidative stress. Oxidative stress increases lipid peroxidation and the formation of pro-inflammatory isolevuglandins (IsoLG). Long noncoding RNAs (lncRNAs) play a crucial role in regulating gene expression, and MALAT1, broadly expressed across cell types, including blood vessels and inflammatory cells, is also associated with inflammation regulation. In hypertension, the decreased transcriptional activity of nuclear factor erythroid 2-related factor 2 (Nrf2 or Nfe2l2) correlates with heightened oxidative stress in APCs and impaired control of various antioxidant genes. Kelch-like ECH-associated protein 1 (Keap1), an intracellular inhibitor of Nrf2, exhibits elevated levels of hypertension. Sodium, through an increase in Sp1 transcription factor binding at its promoter, upregulates MALAT1 expression. Silencing MALAT1 inhibits sodium-induced Keap1 upregulation, facilitating the nuclear translocation of Nrf2 and subsequent antioxidant gene transcription. Thus, MALAT1, acting via the Keap1-Nrf2 pathway, modulates antioxidant defense in hypertension. This review explores the potential role of the lncRNA MALAT1 in controlling the Keap1-Nrf2-antioxidant defense pathway in salt-induced hypertension. The inhibition of MALAT1 holds therapeutic potential for the progression of salt-induced hypertension and cardiovascular disease (CVD).

Beyond the genome: MALAT1's role in advancing urologic cancer care

Urologic cancers (UCs), which include bladder, kidney, and prostate tumors, account for almost a quarter of all malignancies. Long non-coding RNAs (lncRNAs) are tissue-specific RNAs that influence cell growth, death, and division. LncRNAs are dysregulated in UCs, and their abnormal expression may allow them to be used in cancer detection, outlook, and therapy. With the identification of several novel lncRNAs and significant exploration of their functions in various illnesses, particularly cancer, the study of lncRNAs has evolved into a new obsession. MALAT1 is a flexible tumor regulator implicated in an array of biological activities and disorders, resulting in an important research issue. MALAT1 appears as a hotspot, having been linked to the dysregulation of cell communication, and is intimately linked to cancer genesis, advancement, and response to treatment. MALAT1 additionally operates as a competitive endogenous RNA, binding to microRNAs and resuming downstream mRNA transcription and operation. This regulatory system influences cell growth, apoptosis, motility, penetration, and cell cycle pausing. MALAT1's evaluation and prognosis significance are highlighted, with a thorough review of its manifestation levels in several UC situations and its association with clinicopathological markers. The investigation highlights MALAT1's adaptability as a possible treatment target, providing fresh ways for therapy in UCs as we integrate existing information The article not only gathers current knowledge on MALAT1's activities but also lays the groundwork for revolutionary advances in the treatment of UCs.

Role of long noncoding RNAs in pathological cardiac remodeling after myocardial infarction: An emerging insight into molecular mechanisms and therapeutic potential

Myocardial infarction (MI) is the leading cause of heart failure (HF), accounting for high mortality and morbidity worldwide. As a consequence of ischemia/reperfusion injury during MI, multiple cellular processes such as oxidative stress-induced damage, cardiomyocyte death, and inflammatory responses occur. In the next stage, the proliferation and activation of cardiac fibroblasts results in myocardial fibrosis and HF progression. Therefore, developing a novel therapeutic strategy is urgently warranted to restrict the progression of pathological cardiac remodeling. Recently, targeting long non-coding RNAs (lncRNAs) provided a novel insight into treating several disorders. In this regard, numerous investigations have indicated that several lncRNAs could participate in the pathogenesis of MI-induced cardiac remodeling, suggesting their potential therapeutic applications. In this review, we summarized lncRNAs displayed in the pathophysiology of cardiac remodeling after MI, emphasizing molecular mechanisms. Also, we highlighted the possible translational role of lncRNAs as therapeutic targets for this condition and discussed the potential role of exosomes in delivering the lncRNAs involved in post-MI cardiac remodeling.

Non-coding RNAs: targets for Chinese herbal medicine in treating myocardial fibrosis

Cardiovascular diseases have become the leading cause of death in urban and rural areas. Myocardial fibrosis is a common pathological manifestation at the adaptive and repair stage of cardiovascular diseases, easily predisposing to cardiac death. Non-coding RNAs (ncRNAs), RNA molecules with no coding potential, can regulate gene expression in the occurrence and development of myocardial fibrosis. Recent studies have suggested that Chinese herbal medicine can relieve myocardial fibrosis through targeting various ncRNAs, mainly including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Thus, ncRNAs are novel drug targets for Chinese herbal medicine. Herein, we summarized the current understanding of ncRNAs in the pathogenesis of myocardial fibrosis, and highlighted the contribution of ncRNAs to the therapeutic effect of Chinese herbal medicine on myocardial fibrosis. Further, we discussed the future directions regarding the potential applications of ncRNA-based drug screening platform to screen drugs for myocardial fibrosis.

Epigenetic signatures in cardiac fibrosis: Focusing on noncoding RNA regulators as the gatekeepers of cardiac fibroblast identity

Cardiac fibroblasts play a pivotal role in cardiac fibrosis by transformation of fibroblasts into myofibroblasts, which synthesis and secrete a large number of extracellular matrix proteins. Ultimately, this will lead to cardiac wall stiffness and impaired cardiac performance. The epigenetic regulation and fate reprogramming of cardiac fibroblasts has been advanced considerably in recent decades. Non coding RNAs (microRNAs, lncRNAs, circRNAs) regulate the functions and behaviors of cardiac fibroblasts, including proliferation, migration, phenotypic transformation, inflammation, pyroptosis, apoptosis, autophagy, which can provide the basis for novel targeted therapeutic treatments that abrogate activation and inflammation of cardiac fibroblasts, induce different death pathways in cardiac fibroblasts, or make it sensitive to established pathogenic cells targeted cytotoxic agents and biotherapy. This review summarizes our current knowledge in this field of ncRNAs function in epigenetic regulation and fate determination of cardiac fibroblasts as well as the details of signaling pathways contribute to cardiac fibrosis. Moreover, we will comment on the emerging landscape of lncRNAs and circRNAs function in regulating signal transduction pathways, gene translation processes and post-translational regulation of gene expression in cardiac fibroblast. In the end, the prospect of cardiac fibroblasts targeted therapy for cardiac fibrosis based on ncRNAs is discussed.

The role and medical prospects of long non-coding RNAs in cardiovascular disease

Cardiovascular disease (CVD) has reached epidemic proportions and is a leading cause of death worldwide. One of the long-standing goals of scientists is to repair heart tissue damaged by various forms of CVD such as cardiac hypertrophy, dilated cardiomyopathy, myocardial infarction, heart fibrosis, and genetic and developmental heart defects such as heart valve deformities. Damaged or defective heart tissue has limited regenerative capacity and results in a loss of functioning myocardium. Advances in transcriptomic profiling technology have revealed that long noncoding RNA (lncRNA) is transcribed from what was once considered "junk DNA." It has since been discovered that lncRNAs play a critical role in the pathogenesis of various CVDs and in myocardial regeneration. This review will explore how lncRNAs impact various forms of CVD as well as those involved in cardiomyocyte regeneration. Further, we discuss the potential of lncRNAs as a therapeutic modality for treating CVD.

Knockdown of lncRNA MALAT1 attenuates renal interstitial fibrosis through miR-124-3p/ITGB1 axis

Renal interstitial fibrosis (RIF) considered the primary irreversible cause of chronic kidney disease. Recently, accumulating studies demonstrated that lncRNAs play an important role in the pathogenesis of RIF. However, the underlying exact mechanism of lncRNA MALAT1 in RIF remains barely known. Here, the aim of our study was to investigate the dysregulate expression of lncRNA MALAT1 in TGF-β1 treated HK2/NRK-49F cells and unilateral ureteral obstruction (UUO) mice model, defining its effects on HK2/NRK-49F cells and UUO mice fibrosis process through the miR-124-3p/ITGB1 signaling axis. It was found that lncRNA MALAT1 and ITGB1 was significantly overexpression, while miR-124-3p was downregulated in HK2/NRK-49F cells induced by TGF-β1 and in UUO mice model. Moreover, knockdown of lncRNA MALAT1 remarkably downregulated the proteins level of fibrosis-related markers, ITGB1, and upregulated the expression of epithelial marker E-cadherin. Consistently, mechanistic studies showed that miR-124-3p can directly binds to lncRNA MALAT1 and ITGB1. And the protect effect of Len-sh-MALAT1 on fibrosis related protein levels could be partially reversed by co-transfected with inhibitor-miR-124-3p. Moreover, the expression trend of LncRNA MALAT1/miR-124-3p/ITGB1 in renal tissues of patients with obstructive nephropathy (ON) was consistent with the results of cell and animal experiments. Taken together, these results indicated that lncRNA MALAT1 could promote RIF process in vitro and in vivo via the miR-124-3p/ITGB1 signaling pathway. These findings suggest a new regulatory pathway involving lncRNA MALAT1, which probably serves as a potential therapeutic target for RIF.

Malat1 promotes macrophage-associated inflammation by increasing PPAR-γ methylation through binding to EZH2 in acute myocardial infarction

The inflammatory microenvironment of macrophage plays an important role in acute myocardial infarction (AMI), but the regulatory mechanism is unknown. Here, we aimed to investigate the role of Malat1 on inflammation microenvironment of macrophage in AMI. Our study found that Malat1 expression was increased in AMI, which mainly expressed in macrophages. Malat1 inhibition improved collagen deposition and inflammation in infarcted heart. In vitro, Malat1 inhibition evidently reduced macrophage-associated inflammation. The results from ribonucleic acid pull-down (RNA pull-down) and RNA Immunoprecipitation (RIP) assay demonstrated that Malat1 directly binds to EZH2. Malat1 and EZH2 complex could increase histone H3K27me3 expression and further inhibit the production of PPAR-γ. In vivo, inhibition of Malat1 also leaded to the down-regulation of both EZH2 and H3K27me3, as well as up-regulation of PPAR-γ in infarcted heart. Therefore, these findings demonstrate a novel mechanism of Malat1 on inflammation microenvironment of macrophage in AMI, which provide a new target for its treatment.

MircroRNA-145 Attenuates Cardiac Fibrosis Via Regulating Mitogen-Activated Protein Kinase Kinase Kinase 3

PURPOSE

This study aimed to explore the effect of microRNA (miR)-145 on cardiac fibrosis in heart failure mice and its target.

METHODS

Experiments were carried out in mice receiving left coronary artery ligation, transverse aortic constriction (TAC), or angiotensin (Ang) II to trigger heart failure, and in cardiac fibroblasts (CFs) with Ang II-induced fibrosis.

RESULTS

The miR-145 levels were decreased in the mice hearts of heart failure induced by myocardial infarction (MI), TAC or Ang II infusion, and in the Ang II-treated CFs. The impaired cardiac function was ameliorated by miR-145 agomiR in MI mice. The increased fibrosis and the levels of collagen I, collagen III, and transforming growth factor-beta (TGF-β) in MI mice were inhibited by miR-145 agomiR or miR-145 transgene (TG). The agomiR of miR-145 also attenuated the increases of collagen I, collagen III, and TGF-β in Ang II-treated CFs. Bioinformatics analysis and luciferase reporter assays indicated that mitogen-activated protein kinase kinase kinase 3 (MAP3K3) was a direct target gene of miR-145. MAP3K3 expression was suppressed by MiR-145 in CFs, while the MAP3K3 over-expression reversed the inhibiting effects of miR-145 agomiR on the Ang II-induced increases of collagen I, collagen III, and TGF-β in CFs.

CONCLUSION

These results indicated that miR-145 upregulation could improve cardiac dysfunction and cardiac fibrosis by inhibiting MAP3K3 in heart failure. Thus, upregulating miR-145 or blocking MAP3K3 can be used to treat heart failure and cardiac fibrosis.

Bioactive Compounds and Cardiac Fibrosis: Current Insight and Future Prospect

Cardiac fibrosis is a pathological condition characterized by excessive deposition of collagen and other extracellular matrix components in the heart. It is recognized as a major contributor to the development and progression of heart failure. Despite significant research efforts in characterizing and identifying key molecular mechanisms associated with myocardial fibrosis, effective treatment for this condition is still out of sight. In this regard, bioactive compounds have emerged as potential therapeutic antifibrotic agents due to their anti-inflammatory and antioxidant properties. These compounds exhibit the ability to modulate fibrogenic processes by inhibiting the production of extracellular matrix proteins involved in fibroblast to myofibroblast differentiation, or by promoting their breakdown. Extensive investigation of these bioactive compounds offers new possibilities for preventing or reducing cardiac fibrosis and its detrimental consequences. This comprehensive review aims to provide a thorough overview of the mechanisms underlying cardiac fibrosis, address the limitations of current treatment strategies, and specifically explore the potential of bioactive compounds as therapeutic interventions for the treatment and/or prevention of cardiac fibrosis.

The Role of ncRNAs in Cardiac Infarction and Regeneration

Myocardial infarction is the most prevalent cardiovascular disease worldwide, and it is defined as cardiomyocyte cell death due to a lack of oxygen supply. Such a temporary absence of oxygen supply, or ischemia, leads to extensive cardiomyocyte cell death in the affected myocardium. Notably, reactive oxygen species are generated during the reperfusion process, driving a novel wave of cell death. Consequently, the inflammatory process starts, followed by fibrotic scar formation. Limiting inflammation and resolving the fibrotic scar are essential biological processes with respect to providing a favorable environment for cardiac regeneration that is only achieved in a limited number of species. Distinct inductive signals and transcriptional regulatory factors are key components that modulate cardiac injury and regeneration. Over the last decade, the impact of non-coding RNAs has begun to be addressed in many cellular and pathological processes including myocardial infarction and regeneration. Herein, we provide a state-of-the-art review of the current functional role of diverse non-coding RNAs, particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in different biological processes involved in cardiac injury as well as in distinct experimental models of cardiac regeneration.

Malat1 deficiency prevents neonatal heart regeneration by inducing cardiomyocyte binucleation

The adult mammalian heart has limited regenerative capacity, while the neonatal heart fully regenerates during the first week of life. Postnatal regeneration is mainly driven by proliferation of preexisting cardiomyocytes and supported by proregenerative macrophages and angiogenesis. Although the process of regeneration has been well studied in the neonatal mouse, the molecular mechanisms that define the switch between regenerative and nonregenerative cardiomyocytes are not well understood. Here, using in vivo and in vitro approaches, we identified the lncRNA Malat1 as a key player in postnatal cardiac regeneration. Malat1 deletion prevented heart regeneration in mice after myocardial infarction on postnatal day 3 associated with a decline in cardiomyocyte proliferation and reparative angiogenesis. Interestingly, Malat1 deficiency increased cardiomyocyte binucleation even in the absence of cardiac injury. Cardiomyocyte-specific deletion of Malat1 was sufficient to block regeneration, supporting a critical role of Malat1 in regulating cardiomyocyte proliferation and binucleation, a landmark of mature nonregenerative cardiomyocytes. In vitro, Malat1 deficiency induced binucleation and the expression of a maturation gene program. Finally, the loss of hnRNP U, an interaction partner of Malat1, induced similar features in vitro, suggesting that Malat1 regulates cardiomyocyte proliferation and binucleation by hnRNP U to control the regenerative window in the heart.

Vaccine Formulation Strategies and Challenges Involved in RNA Delivery for Modulating Biomarkers of Cardiovascular Diseases: A Race from Laboratory to Market

It has been demonstrated that noncoding RNAs have significant physiological and pathological roles. Modulation of noncoding RNAs may offer therapeutic approaches as per recent findings. Small RNAs, mostly long noncoding RNAs, siRNA, and microRNAs make up noncoding RNAs. Inhibiting or promoting protein breakdown by binding to 3' untranslated regions of target mRNA, microRNAs post-transcriptionally control the pattern of gene expression. Contrarily, long non-coding RNAs perform a wider range of tasks, including serving as molecular scaffolding, decoys, and epigenetic regulators. This article provides instances of long noncoding RNAs and microRNAs that may be a biomarker of CVD (cardiovascular disease). In this paper we highlight various RNA-based vaccine formulation strategies designed to target these biomarkers-that are either currently in the research pipeline or are in the global pharmaceutical market-along with the physiological hurdles that need to be overcome.

The Function and Therapeutic Potential of lncRNAs in Cardiac Fibrosis

Cardiac fibrosis remains an unresolved problem in cardiovascular diseases. Fibrosis of the myocardium plays a key role in the clinical outcomes of patients with heart injuries. Moderate fibrosis is favorable for cardiac structure maintaining and contractile force transmission, whereas adverse fibrosis generally progresses to ventricular remodeling and cardiac systolic or diastolic dysfunction. The molecular mechanisms involved in these processes are multifactorial and complex. Several molecular mechanisms, such as TGF-β signaling pathway, extracellular matrix (ECM) synthesis and degradation, and non-coding RNAs, positively or negatively regulate myocardial fibrosis. Long noncoding RNAs (lncRNAs) have emerged as significant mediators in gene regulation in cardiovascular diseases. Recent studies have demonstrated that lncRNAs are crucial in genetic programming and gene expression during myocardial fibrosis. We summarize the function of lncRNAs in cardiac fibrosis and their contributions to miRNA expression, TGF-β signaling, and ECMs synthesis, with a particular attention on the exosome-derived lncRNAs in the regulation of adverse fibrosis as well as the mode of action of lncRNAs secreted into exosomes. We also discuss how the current knowledge on lncRNAs can be applied to develop novel therapeutic strategies to prevent or reverse cardiac fibrosis.

New developments in non-exosomal and exosomal ncRNAs in coronary artery disease

Aim & methods: Non-exosomal and exosomal ncRNAs have been reported to be involved in the regulation of coronary artery disease (CAD). Therefore, to explore the biological effects of non-exosomal/exosomal ncRNAs in CAD, the authors searched for studies published in the last 3 years on these ncRNAs in CAD and summarized their functions and mechanisms. Results: The authors summarized 120 non-exosomal ncRNAs capable of regulating CAD progression. In clinical studies, 47 non-exosomal and nine exosomal ncRNAs were able to serve as biomarkers for the diagnosis of CAD. Conclusion: Non-exosomal/exosomal ncRNAs are not only able to serve as biomarkers for CAD diagnosis but can also regulate CAD progression through ceRNA mechanisms and are a potential target for early clinical intervention in CAD.

Single-Cell RNA Sequencing Reveals Distinct Cardiac-Derived Stromal Cell Subpopulations

Human cardiac-derived c-kit+ stromal cells (CSCs) have demonstrated efficacy in preclinical trials for the treatment of heart failure and myocardial dysfunction. Unfortunately, large variability in patient outcomes and cell populations remains a problem. Previous research has demonstrated that the reparative capacity of CSCs may be linked to the age of the cells: CSCs derived from neonate patients increase cardiac function and reduce fibrosis. However, age-dependent differences between CSC populations have primarily been explored with bulk sequencing methods. In this work, we hypothesized that differences in CSC populations and subsequent cell therapy outcomes may arise from differing cell subtypes within donor CSC samples. We performed single-cell RNA sequencing on four neonatal CSC (nCSC) and five child CSC (cCSC) samples. Subcluster analysis revealed cCSC-enriched clusters upregulated in several fibrosis- and immune response-related genes. Module-based analysis identified upregulation of chemotaxis and ribosomal activity-related genes in nCSCs and upregulation of immune response and fiber synthesis genes in cCSCs. Further, we identified versican and integrin alpha 2 as potential markers for a fibrotic cell subtype. By investigating differences in patient-derived CSC populations at the single-cell level, this research aims to identify and characterize CSC subtypes to better optimize CSC-based therapy and improve patient outcomes.

miR-409-3p Regulated by GATA2 Promotes Cardiac Fibrosis through Targeting Gpd1

Cardiac fibrosis is a hallmark of numerous chronic cardiovascular diseases that leads to heart failure. However, there is no validated therapy for it. Dysregulation of microRNAs has been confirmed to be involved in cardiac fibrosis development. However, the regulatory network was not well explored. This study was the first to highlight the role and molecular mechanism of miR-409-3p in cardiac fibrosis. We found that miR-409-3p was consistently increased in three fibrotic models, including heart tissues of postmyocardial infarction (MI) mice and neonatal rat cardiac fibroblasts treated with angiotensin II (Ang II) or transforming growth factor-β (TGF-β). Furthermore, myocardial infarction surgery-induced cardiac fibrosis and dysfunction were attenuated by systemic delivery of miR-409-3p antagomir. Notably, transfection with miR-409-3p mimics promoted the proliferation of cardiac fibroblasts and fibroblast-to-myofibroblast differentiation, accompanied by upregulated expression of Col1a1, Col3a1, and α-SMA. On the contrary, the miR-409-3p inhibitor exhibited the opposite effect. Following this, we verified Gpd1 as a direct target of miR-409-3p. Gpd1 siRNA abolished the antifibrotic effect of miR-409-3p inhibitor in neonatal rat cardiac fibroblasts, suggesting that miR-409-3p promotes cardiac fibrosis at least partially through Gpd1. Moreover, GATA2 was identified as a cardiac fibrosis-associated upstream positive transcription factor of miR-409-3p. Finally, these findings suggest that modulating miR-409-3p could be a potential therapeutic method for cardiac fibrosis.

lncRNA Vgll3 Regulates the Activated Proliferation of Mouse Myocardial Fibroblasts through TGF-β3-Related Pathway

Background

Cardiac fibrosis is a risk factor leading to various cardiac diseases, and its mechanism has not been clarified. However, long noncoding RNA (lncRNA) can mediate the pathological process of cardiac fibrosis.

Objective

This study is aimed at determining the pathological role of lncRNA Vgll3 in cardiac fibrosis and explore its potential mechanism.

Methods

Myocardium fibroblasts (CFs) were isolated from mice and stimulated with angiotensin II (Ang-II). The expression of Vgll3 and transforming growth factor-β3 (TGF-β3) were detected by real-time fluorescence quantitative PCR (qPCR). Double luciferase reporter gene and western blot analysis (WB) were used to detect the effect of Vgll3 on TGF-β3 expression. The qPCR and WB were used to detect TGF-β3 pathway markers such as TGF-β3 and SMAD4, as well as cardiac fibrosis markers such as α-smooth muscle actin (α-SMA), fibronectin (Fn), and type I collagen (Col1). The proliferation of CFs in mice was analyzed by Cell Counting Kit-8 (CCK8) and 5-bromo-2-deoxyuracil (EdU) method.

Results

Upregulation of Vgll3 promoted the expression of TGF-β3 and its downstream molecules in mouse CFs, while silencing of Vgll3 inhibited the TGF-β3 pathway. Upregulation of Vgll3 significantly promoted the activation and proliferation of mouse CFs cells. It promoted the mRNA and protein levels of α-SMA, Fn, Col1, and Col3, while silencing the expression of Vgll3 had the opposite effect. The above effects of upregulation of Vgll3 were counteracted by TGF-β3 knockdown intervention.

Conclusion

Vgll3 can promote the activation and proliferation of CFs in mice by activating TGF-β3-related pathway.

Non-coding RNAs: Important participants in cardiac fibrosis

Cardiac remodeling is a pathophysiological process activated by diverse cardiac stress, which impairs cardiac function and leads to adverse clinical outcome. This remodeling partly attributes to cardiac fibrosis, which is a result of differentiation of cardiac fibroblasts to myofibroblasts and the production of excessive extracellular matrix within the myocardium. Non-coding RNAs mainly include microRNAs and long non-coding RNAs. These non-coding RNAs have been proved to have a profound impact on biological behaviors of various cardiac cell types and play a pivotal role in the development of cardiac fibrosis. This review aims to summarize the role of microRNAs and long non-coding RNAs in cardiac fibrosis associated with pressure overload, ischemia, diabetes mellitus, aging, atrial fibrillation and heart transplantation, meanwhile shed light on the diagnostic and therapeutic potential of non-coding RNAs for cardiac fibrosis.

Downregulation of lncRNA MALAT1 Inhibits Angiotensin II-induced Hypertrophic Effects of Cardiomyocytes by Regulating SIRT4 via miR-93-5p

Cardiac hypertrophy is a leading risk for heart failure and sudden death. Long non-coding RNAs (lncRNAs) have been implicated in a variety of human diseases, including cardiac hypertrophy. We aimed to investigate the potential role and functional mechanism of lncRNA metastasis-associated in lung adenocarcinoma transcript 1 (MALAT1) in cardiac hypertrophy. C57BL/6 mice underwent transverse aortic constriction (TAC) to induce cardiac hypertrophy in vivo. The expression of MALAT1, miR-93-5p, and sirtuin 4 (SIRT4) mRNA was detected using a quantitative real-time polymerase chain reaction. The protein levels of cardiac hypertrophy-related markers, including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC), and SIRT4 were measured via western blotting. The putative interaction between miR-93-5p and MALAT1 or SIRT4 was verified using a dual-luciferase reporter assay, RNA immunoprecipitation assay, or pull-down assay. Consequently, the expression of MALAT1 and SIRT4 was increased in TAC-treated mouse heart and angiotensin II (Ang-II)-induced cardiomyocytes, whereas the expression of miR-93-5p was decreased. Ang-II promoted the expression of ANP, BNP, and β-MHC and the surface area of cardiomyocytes, whereas MALAT1 downregulation impaired their expression and cell area. MiR-93-5p was a target of MALAT1, and its inhibition reversed the effects of MALAT1 downregulation. More importantly, MALAT1 modulated SIRT4 expression by degrading miR-93-5p. The expression of ANP, BNP, and β-MHC suppressed by miR-93-5p restoration was recovered by SIRT4 promotion. Overall, MALAT1 knockdown ameliorated cardiac hypertrophy partly by regulating the miR-93-5p/SIRT4 network, indicating that MALAT1 was a substantial indicator of cardiac hypertrophy.

Cardiac fibroblast sub-types in vitro reflect pathological cardiac remodeling in vivo

•

A panel of 12 fibrosis related genes clearly identified heart failure (HF) patients better than measurement of the collagen-related hydroxyproline content.

•

A subcluster enriched for ischemic HF was recognized, but not for diabetes, obesity, or gender.

•

Single-cell transcriptomic analysis of in vitro differentiated mouse cardiac fibroblasts distinguished 6 subpopulations, including a contractile Acta2high precursor population, and Acta2low subpopulations with high production of extracellular matrix molecules.

•

The 12 gene profile identified in HF patients showed highest similarity to the fibroblast subset with the strongest expression of extracellular matrix molecules.

•

Major features of cardiac fibroblast differentiation in heart failure patients, in murine heart disease models, and in cell culture of primary murine cardiac fibroblast are shared.

Many heart diseases are associated with fibrosis, but it is unclear whether different types of heart disease correlate with different subtypes of activated fibroblasts and to which extent such diversity is modeled during in vitro activation of primary cardiac fibroblasts. Analyzing the expression of 82 fibrosis related genes in 65 heart failure (HF) patients, we identified a panel of 12 genes clearly distinguishing HF patients better from healthy controls than measurement of the collagen-related hydroxyproline content. A subcluster enriched in ischemic HF was recognized, but not for diabetes, high BMI, or gender. Single-cell transcriptomic analysis of in vitro activated mouse cardiac fibroblasts distinguished 6 subpopulations, including a contractile Acta2^high precursor population, which was predicted by time trajectory analysis to develop into Acta2^low subpopulations with high production of extracellular matrix molecules. The 12 gene profile identified in HF patients showed highest similarity to the fibroblast subset with the strongest expression of extracellular matrix molecules. Population markers identified were furthermore able to clearly cluster different disease stages in a murine model for myocardial infarct. These data suggest that major features of cardiac fibroblast activation in heart failure patients, in murine heart disease models, and in cell culture of primary murine cardiac fibroblast are shared.

Long noncoding RNA MALAT1 polymorphism predicts MACCEs in patients with myocardial infarction

Background

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) participates in the occurrence and development of cardiovascular and cerebrovascular diseases such as stroke and coronary heart disease by regulating inflammatory reactions, programmed cell death, and other pathological processes. Previous studies revealed that the MALAT1 gene polymorphism was associated with cardiac and cerebrovascular diseases. However, the prognostic role of the MALAT1 polymorphism in major adverse cardiac and cerebrovascular events (MACCEs) remains unknown. Therefore, this study intends to explore the association between the MALAT1 rs3200401 polymorphism and MACCEs.

Method

We enrolled 617 myocardial infarction (MI) patients and 1125 control participants who attended the First Affiliated Hospital of Xinjiang Medical University from January 2010 to 2018. SNPscan™ typing assays were used to detect the MALAT1 rs3200401 genotype. During the follow-up, MACCEs were recorded. Kaplan–Meier curves and univariate and multivariate Cox survival analyses were used to explore the correlation between MALAT1 gene polymorphisms and the occurrence of MACCEs.

Results

Among the total participants and MI patients, the frequencies of the T allele (total Participants 19.5% vs. 15.3%, P = 0.047, MI patients 20.7% vs. 14.1%, P = 0.014) and CT + TT genotypes (total Participants 37.4% vs. 28.1%, P = 0.013, MI patients 39.5% vs. 25.8%, P = 0.003) were significantly higher in subjects with MACCEs than in subjects without MACCEs. However, in control participants, the frequencies of the T allele (16.6% vs. 16.0%, P = 0.860) and CT + TT genotypes (31.4% vs. 29.3%, P = 0.760) were not higher in subjects with MACCEs than in subjects without MACCEs. In addition, among the total participants and MI patients, the Kaplan–Meier curve analysis indicated that the subjects with rs3200401 CT + TT genotypes had a higher incidence of MACCEs than CC genotype carriers (P = 0.015, P = 0.001). Nevertheless, similar results were not observed in the control participants (P = 0.790). Multivariate Cox regression indicated that compared with patients with the CC genotype, patients with CT + TT genotypes had a 1.554-fold increase in MACCE risk (hazard ratio: 1.554, 95% confidence interval: 1.060–2.277, P = 0.024).

Conclusions

The MALAT1 rs3200401 CT + TT genotypes could be a risk factor for MACCEs in MI patients, suggesting that the MALAT1 gene may become a biomarker for poor prognosis in MI patients.

Signaling pathways and targeted therapy for myocardial infarction

Although the treatment of myocardial infarction (MI) has improved considerably, it is still a worldwide disease with high morbidity and high mortality. Whilst there is still a long way to go for discovering ideal treatments, therapeutic strategies committed to cardioprotection and cardiac repair following cardiac ischemia are emerging. Evidence of pathological characteristics in MI illustrates cell signaling pathways that participate in the survival, proliferation, apoptosis, autophagy of cardiomyocytes, endothelial cells, fibroblasts, monocytes, and stem cells. These signaling pathways include the key players in inflammation response, e.g., NLRP3/caspase-1 and TLR4/MyD88/NF-κB; the crucial mediators in oxidative stress and apoptosis, for instance, Notch, Hippo/YAP, RhoA/ROCK, Nrf2/HO-1, and Sonic hedgehog; the controller of myocardial fibrosis such as TGF-β/SMADs and Wnt/β-catenin; and the main regulator of angiogenesis, PI3K/Akt, MAPK, JAK/STAT, Sonic hedgehog, etc. Since signaling pathways play an important role in administering the process of MI, aiming at targeting these aberrant signaling pathways and improving the pathological manifestations in MI is indispensable and promising. Hence, drug therapy, gene therapy, protein therapy, cell therapy, and exosome therapy have been emerging and are known as novel therapies. In this review, we summarize the therapeutic strategies for MI by regulating these associated pathways, which contribute to inhibiting cardiomyocytes death, attenuating inflammation, enhancing angiogenesis, etc. so as to repair and re-functionalize damaged hearts.

Role of N6-methyladenosine Modification in Cardiac Remodeling

Cardiac remodeling is the critical process in heart failure due to many cardiovascular diseases including myocardial infarction, hypertension, cardiovascular disease and cardiomyopathy. However, treatments for heart failure focusing on cardiac remodeling show relatively limited effectiveness. In recent decades, epitranscriptomic modifications were found abundantly present throughout the progression of cardiac remodeling, and numerous types of biochemical modifications were identified. m6A modification is the methylation of the adenosine base at the nitrogen-6 position, and dysregulation of m6A modification has been implicated in a wide range of diseases. However, function of m6A modifications still remain largely unknown in cardiac diseases, especially cardiac remodeling. LncRNAs are also shown to play a vital role in the pathophysiology of cardiac remodeling and heart failure. The crosstalk between lncRNAs and m6A modification provides a novel prospective for exploring possible regulatory mechanism and therapeutic targets of cardiac remodeling. This review summarizes the role of m6A modification in cardiac remodeling in the current researches.

Long non-coding RNA MALAT1 silencing elevates microRNA-26a-5p to ameliorate myocardial injury in sepsis by reducing regulator of calcineurin 2

OBJECTIVE

Sepsis is a leading cause of morbidity and mortality after surgery. We aimed to explore the role of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) sponging microRNA-26a-5p in sepsis-induced myocardial injury by regulating regulator of calcineurin 2 (Rcan2).

METHODS

HL-1 cells were incubated with lipopolysaccharide (LPS) to induce in vitro cardiomyocyte injury models, which were then treated with silenced MALAT1 vector, miR-26a-5p mimic or Rcan2 overexpression vector. Next, inflammatory factor level and apoptosis of cells were determined. The in vivo mouse models were constructed by intraperitoneal injection of LPS. The modeled mice were injected with relative oligonucleotides and the pathology, apoptosis, and inflammation in mouse myocardial tissues were assessed. Expression of MALAT1, miR-26a-5p and Rcan2 in vivo and in vitro was evaluated.

RESULTS

MALAT1 and Rcan2 were upregulated while miR-26a-5p was downregulated in LPS-treated HL-1 cells and mice. MALAT1 silencing or miR-26a-5p upregulation suppressed LPS-induced inflammation and apoptosis of cardiomyocytes in cellular and animal models. These effects of elevated miR-26a-5p could be reversed by upregulating Rcan2, and MALAT1 knockdown-induced ameliorative impacts could be reversed by miR-26a-5p downregulation.

CONCLUSION

MALAT1 silencing elevated miR-26a-5p to ameliorate LPS-induced myocardial injury by reducing Rcan2. Our research may provide novel biomarkers for the treatment of sepsis.

Targeting Epigenetics and Non-coding RNAs in Myocardial Infarction: From Mechanisms to Therapeutics

Myocardial infarction (MI) is a complicated pathology triggered by numerous environmental and genetic factors. Understanding the effect of epigenetic regulation mechanisms on the cardiovascular disease would advance the field and promote prophylactic methods targeting epigenetic mechanisms. Genetic screening guides individualised MI therapies and surveillance. The present review reported the latest development on the epigenetic regulation of MI in terms of DNA methylation, histone modifications, and microRNA-dependent MI mechanisms and the novel therapies based on epigenetics.

Novel and Annotated Long Noncoding RNAs Associated with Ischemia in the Human Heart

BACKGROUND

Long noncoding RNAs (lncRNAs) have been implicated in the pathogenesis of cardiovascular diseases. We aimed to identify novel lncRNAs associated with the early response to ischemia in the heart.

METHODS AND RESULTS

RNA sequencing data gathered from 81 paired left ventricle samples from patients undergoing cardiopulmonary bypass was collected before and after a period of ischemia. Novel lncRNAs were validated with Oxford Nanopore Technologies long-read sequencing. Gene modules associated with an early ischemic response were identified and the subcellular location of selected lncRNAs was determined with RNAscope. A total of 2446 mRNAs, 270 annotated lncRNAs and one novel lncRNA differed in response to ischemia (adjusted p < 0.001, absolute fold change >1.2). The novel lncRNA belonged to a gene module of highly correlated genes that also included 39 annotated lncRNAs. This module associated with ischemia (Pearson correlation coefficient = -0.69, p = 1 × 10^-23) and activation of cell death pathways (p < 6 × 10^-9). A further nine novel cardiac lncRNAs were identified, of which, one overlapped five cis-eQTL eSNPs for the gene RWD Domain-Containing Sumoylation Enhancer (RWDD3) and was itself correlated with RWDD3 expression (Pearson correlation coefficient -0.2, p = 0.002).

CONCLUSION

We have identified 10 novel lncRNAs, one of which was associated with myocardial ischemia and may have potential as a novel therapeutic target or early marker for myocardial dysfunction.

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.

TUG1 knockdown suppresses cardiac fibrosis after myocardial infarction

Cardiac fibrosis is involved in myocardial remodeling following acute myocardial infarction (AMI), which can result in heart failure, arrhythmias and even sudden cardiac death. Investigating the molecular mechanisms of cardiac fibrosis in acute myocardial infarction (AMI) is essential for better understanding this pathology. The current study aims to investigate the effect of TUG1 on cardiac fibrosis after AMI and elucidated the underlying molecular mechanism of AMI. Rats were randomly divided into four groups (sham-operation group, myocardial infarction group (AMI group), si-NC treated group and si-TUG1 treated group). The biological behavior of cardiac fibroblasts treated with TGF-β1after being transfected by si-TUG1 or miR-590 mimic or miR-590 inhibitor or FGF1 mimic or a combination was evaluated using the cell counting kit-8 (CCK8) and Transwell assays. SatarBase v2.0 was used to predict the target microRNAs binding site candidates with TUG1 and FGF1. Western blot and recovery experiments were used to explore the potential mechanism. TUG1 expression was up-regulated and knockdown of TUG1 improved cardiac function in AMI rats. Knockdown of TUG1 suppressed cell viability and migration and improved collagen production of TGF-β1 treated cardiac fibroblasts. SatarBase v2.0 showed TUG1 served as a sponge for miR-590 and FGF1 is a direct target of miR-590. TUG1 expression was increased in AMI tissue and cardiac fibroblasts treated with TGF-β1. TUG1 knockdown suppressed the biological process of cardiac fibroblasts treated with TGF-β1 by sponging miR-590.

Role of the microRNA-29 family in myocardial fibrosis

Myocardial fibrosis (MF) is an inevitable pathological process in the terminal stage of many cardiovascular diseases, often leading to serious cardiac dysfunction and even death. Currently, microRNA-29 (miR-29) is thought to be a novel diagnostic and therapeutic target of MF. Understanding the underlying mechanisms of miR-29 that regulate MF will provide a new direction for MF therapy. In the present review, we concentrate on the underlying signaling pathway of miR-29 affecting MF and the crosstalk regulatory relationship among these pathways to illustrate the complex regulatory network of miR-29 in MF. Additionally, based on our mechanistic understanding, we summarize opportunities and challenges of miR-29-based MF diagnosis and therapy.

Epigenetic alterations of TGFβ and its main canonical signaling mediators in the context of cardiac fibrosis

Cardiac fibrosis is a pathological process that presents a continuous overproduction of extracellular matrix (ECM) components in the myocardium, which negatively influences the progression of many cardiac diseases. Transforming growth factor β (TGFβ) is the main ligand that triggers the production of pro-fibrotic ECM proteins. In the cardiac fibrotic process, TGFβ and its canonical signaling mediators are tightly regulated at different levels as well as epigenetically. Cardiac fibroblasts are one of the most important TGFβ target cells activated after cardiac injury. TGFβ-driven fibroblast activation is subject to epigenetic modulation and contributes to the progression of cardiac fibrosis, mainly through the expression of pro-fibrotic molecules implicated in the disease. In this review, we describe epigenetic regulation related to canonical TGFβ signaling in cardiac fibroblasts.

Role of N6-Methyladenosine RNA Modification in Cardiovascular Disease

Despite treatments being improved and many risk factors being identified, cardiovascular disease (CVD) is still a leading cause of mortality and disability worldwide. N⁶-methyladenosine (m⁶A) is the most common, abundant, and conserved internal modification in RNAs and plays an important role in the development of CVD. Many studies have shown that aabnormal m⁶A modifications of coding RNAs are involved in the development of CVD. In addition, non-coding RNAs (ncRNAs) exert post-transcriptional regulation in many diseases including CVD. Although ncRNAs have also been found to be modified by m⁶A, the studies on m⁶A modifications of ncRNAs in CVD are currently lacking. In this review, we summarized the recent progress in understanding m⁶A modifications in the context of coding RNAs and ncRNAs, as well as their regulatory roles in CVD.

Knockdown of ZFAS1 improved the cardiac function of myocardial infarction rats via regulating Wnt/β-catenin signaling pathway

Myocardial infarction (MI) is a big health threat in the world, and it is characterized by high morbidity and mortality. However, current treatments are not effective enough, and novel therapeutic strategies need to be explored. ZFAS1 has been proved to be involved in the regulation of MI, but the specific mechanism remains unclear. MI rats were constructed through left anterior descending artery ligation, and hypoxia cell model was also established. The proliferation, invasion, and migration of cells were detected via CCK8, traswell, and wound healing methods. Immunohistochemistry staining, western blotting, and qRT-PCR were used to detect the levels of molecules. Knockdown of ZFAS1 significantly increased the proliferation, migration, and invasion of cardiac fibroblasts. Knockdown of ZFAS1 remarkably improved cardiac function via decreasing infarction ratio and increasing vWF expression, left ventricular ejection fraction, and left ventricular fractional shortening compared with group MI. Knockdown of ZFAS1 also suppressed Wnt/β-catenin pathway in vivo. The inhibition of Wnt/β-catenin remarkably reversed the influence of shZFAS1 on cardiac function and cardiac fibroblasts viability. Therefore, Knockdown of ZFAS1 could improve the cardiac function of myocardial infarction rats via regulating Wnt/β-catenin signaling pathway. The present study might provide new thoughts for the prevention and treatment of MI damage.

Myofibroblast dedifferentiation proceeds via distinct transcriptomic and phenotypic transitions

Myofibroblasts are the major cellular source of collagen, and their accumulation - via differentiation from fibroblasts and resistance to apoptosis - is a hallmark of tissue fibrosis. Clearance of myofibroblasts by dedifferentiation and restoration of apoptosis sensitivity has the potential to reverse fibrosis. Prostaglandin E2 (PGE2) and mitogens such as FGF2 have each been shown to dedifferentiate myofibroblasts, but - to our knowledge - the resultant cellular phenotypes have neither been comprehensively characterized or compared. Here, we show that PGE2 elicited dedifferentiation of human lung myofibroblasts via cAMP/PKA, while FGF2 utilized MEK/ERK. The 2 mediators yielded transitional cells with distinct transcriptomes, with FGF2 promoting but PGE2 inhibiting proliferation and survival. The gene expression pattern in fibroblasts isolated from the lungs of mice undergoing resolution of experimental fibrosis resembled that of myofibroblasts treated with PGE2 in vitro. We conclude that myofibroblast dedifferentiation can proceed via distinct programs exemplified by treatment with PGE2 and FGF2, with dedifferentiation occurring in vivo most closely resembling the former.

The lncRNA Malat1 regulates microvascular function after myocardial infarction in mice via miR-26b-5p/Mfn1 axis-mediated mitochondrial dynamics

RATIONALE

Myocardial infarction (MI) is a leading cause of cardiovascular mortality globally. The improvement of microvascular function is critical for cardiac repair after MI. Evidence now points to long non-coding RNAs (lncRNAs) as key regulators of cardiac remodelling processes. The lncRNA Malat1 is involved in the development and progression of multiple cardiac diseases. Studies have shown that Malat1 is closely related to the regulation of endothelial cell regeneration. However, the potential molecular mechanisms of Malat1 in repairing cardiac microvascular dysfunction after MI remain unreported.

METHODS AND RESULTS

The present study found that Malat1 is upregulated in the border zone of infarction in mouse hearts, as well as in isolated cardiac microvascular endothelial cells (CMECs). Targeted knockdown of Malat1 in endothelial cells exacerbated oxidative stress, attenuated angiogenesis and microvascular perfusion, and as a result decreased cardiac function in MI mice. Further studies showed that silencing Malat1 obviously inhibited CMEC proliferation, migration and tube formation, which was at least in part attributed to disturbed mitochondrial dynamics and activation of the mitochondrial apoptosis pathway. Moreover, bioinformatic analyses, luciferase assays and pull-down assays indicated that Malat1 acted as a competing endogenous RNA (ceRNA) for miR-26b-5p and formed a signalling axis with Mfn1 to regulate mitochondrial dynamics and endothelial functions. Overexpression of Mfn1 markedly reversed the microvascular dysfunction and CMEC injuries that were aggravated by silencing Malat1 via inhibition of excessive mitochondrial fragments and mitochondria-dependent apoptosis.

CONCLUSIONS

The present study elucidated the functions and mechanisms of Malat1 in cardiac microcirculation repair after MI. The underlying mechanisms of the effects of Malat1 could be attributed to its blocking effects on miR-26b-5p/Mfn1 pathway-mediated mitochondrial dynamics and apoptosis.

Epigenetics-based therapeutics for myocardial fibrosis

Myocardial fibrosis (MF) is a reactive remodeling process in response to myocardial injury. It is mainly manifested by the proliferation of cardiac muscle fibroblasts and secreting extracellular matrix (ECM) proteins to replace damaged tissue. However, the excessive production and deposition of extracellular matrix, and the rising proportion of type I and type III collagen lead to pathological fibrotic remodeling, thereby facilitating the development of cardiac dysfunction and eventually causing heart failure with heightened mortality. Currently, the molecular mechanisms of MF are still not fully understood. With the development of epigenetics, it is found that epigenetics controls the transcription of pro-fibrotic genes in MF by DNA methylation, histone modification and noncoding RNAs. In this review, we summarize and discuss the research progress of the mechanisms underlying MF from the perspective of epigenetics, including the newest m6A modification and crosstalk between different epigenetics in MF. We also offer a succinct overview of promising molecules targeting epigenetic regulators, which may provide novel therapeutic strategies against MF.

Pivotal Role of TGF-β/Smad Signaling in Cardiac Fibrosis: Non-coding RNAs as Effectual Players

Unintended cardiac fibroblast proliferation in many pathophysiological heart conditions, known as cardiac fibrosis, results in pooling of extracellular matrix (ECM) proteins in the heart muscle. Transforming growth factor β (TGF-β) as a pivotal cytokine/growth factor stimulates fibroblasts and hastens ECM production in injured tissues. The TGF-β receptor is a heterodimeric receptor complex on the plasma membrane, made up from TGF-β type I, as well as type II receptors, giving rise to Smad2 and Smad3 transcription factors phosphorylation upon canonical signaling. Phosphorylated Smad2, Smad3, and cytoplasmic Smad4 intercommunicate to transfer the signal to the nucleus, culminating in provoked gene transcription. Additionally, TGF-β receptor complex activation starts up non-canonical signaling that lead to the mitogen-stimulated protein kinase cascade activation, inducing p38, JNK1/2 (c-Jun NH2-terminal kinase 1/2), and ERK1/2 (extracellular signal–regulated kinase 1/2) signaling. TGF-β not only activates fibroblasts and stimulates them to differentiate into myofibroblasts, which produce ECM proteins, but also promotes fibroblast proliferation. Non-coding RNAs (ncRNAs) are important regulators of numerous pathways along with cellular procedures. MicroRNAs and circular long ncRNAs, combined with long ncRNAs, are capable of affecting TGF-β/Smad signaling, leading to cardiac fibrosis. More comprehensive knowledge based on these processes may bring about new diagnostic and therapeutic approaches for different cardiac disorders.

Diagnostic, prognostic, and therapeutic significance of long non-coding RNA MALAT1 in cancer

Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is a widely studied lncRNA in cancer. Although dispensable for normal physiology, MALAT1 is important for cancer-related pathways regulation. It is localized in the nuclear speckles periphery along with centrally located pre-RNA splicing factors. MALAT1 associated cancer signaling pathways include MAPK/ERK, PI3K/AKT, β-catenin/Wnt, Hippo, VEGF, YAP, etc. Molecular tools such as immunoprecipitation, RNA pull-down, reporter assay, Northern blotting, microarray, and q-RT-PCR has been used to elucidate MALAT1's function in cancer pathogenesis. MALAT1 can regulate multiple steps in the development of tumours. The diagnostic and prognostic significance of MALAT1 has been demonstrated in cancers of the breast, cervix, colorectum, gallbladder, lung, ovary, pancreas, prostate, glioma, hepatocellular carcinoma, and multiple myeloma. MALAT1 has also emerged as a novel therapeutic target for solid as well as hematological malignancies. In experimental models, siRNA and antisense oligonucleotide (ASO) based strategy has been used for targeting MALAT1. The lncRNA has also been targeted for the chemosensitization and radiosensitization of cancer cells. However, most studies have been performed in preclinical models. How the cross-talk of MALAT1 with other signaling pathways affect cancer pathogenesis is the focus of this article. The diagnostic, prognostic, and therapeutic significance of MALAT1 in multiple cancer types are discussed.

Circulating exosomes in cardiovascular disease: Novel carriers of biological information

Exosomes are a group of nanosized extracellular vesicles that include various bioactive nucleic acids, lipids, and proteins. They originate from membrane invagination and are released by exocytosis, which can transmit signals to target cells to achieve cell-to-cell communication and maintain homeostasis. The heart is a complex multicellular organ that contains resident cell types such as fibroblasts, endothelial cells, and smooth muscle cells. Communication between different cell types and immune systems is essential for the dynamic equilibrium of the cardiac internal environment. Intercellular communication is a universal phenomenon mediated by exosomes and their contents during several pathological processes in cardiovascular diseases, such as cardiomyocyte hypertrophy, apoptosis, and angiogenesis. Therefore, exosomes can be used as novel invasive diagnostic biomarkers in multiple diseases, including atherosclerosis, myocardial ischemia, cardiac fibrosis, and ischemia-reperfusion injury. In addition, the biocompatible nature and low immunogenicity of exosomes make them high-quality nanoparticle drug carriers with potential applications in translational medicine and therapeutic strategies. Here, we focus on the biogenesis, isolation, biological functions, and future application prospects of exosomes in cardiovascular disease.

Long Noncoding RNAs in Cardiac Development

The exquisite transcriptional control of developmental gene programs is critical for hardwiring the complex expression patterns that govern cell-fate determination and differentiation during heart development. During the past several years, studies have illuminated our understanding of a complex noncoding transcriptional landscape, primarily associated with long noncoding RNAs (lncRNAs), that is implicated in these developmental processes and has begun to reveal key functions of these transcripts. In this review, we discuss the expanding roles for lncRNAs in the earliest points of cardiac development and through differentiation and maturation of multiple cell types within the adult heart. We go on to outline the diverse mechanisms by which cardiovascular lncRNAs orchestrate these transcriptional programs, explore the challenges linked to the study of lncRNAs in developmental phenotypes, and summarize the implications for these molecules in human cardiovascular disorders.

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.

LncRNA MALAT1 promotes wound healing via regulating miR-141-3p/ZNF217 axis

Background

The process of wound healing is complex. Increasing evidences have shown that lncRNA MALAT1 is abundant in fibroblasts and may be engaged in wound healing process. Therefore, we explored the mechanism of MALAT1 affecting wound healing.

Methods

The expression levels of MALAT1, miR-141-3p as well as ZNF217 in human fibroblast cells (HFF-1) were quantified by qRT-PCR. HFF-1 proliferation was measured by MTT, while migration was detected by wound healing assay. SMAD2 activation and matrix proteins expression were detected by western blotting. The interaction between miR-141-3p and MALAT1 or ZNF217 was further confirmed using the luciferase reporter gene assay. In vivo wound healing was assessed by full-thickness wound healing model on C57BL/6 mice.

Result

Knockdown of MALAT1 as well as overexpression miR-141-3p remarkably inhibited the proliferation, migration and matrix protein expression in HFF-1 cells. MALAT1 directly targeted and inhibited the expression of miR-141-3p. MiR-141-3p suppressed the activation of TGF-β2/SMAD2 signaling pathway by targeting ZNF217. Knockdown of MALAT1 inhibited wound healing process in mice.

Conclusions

MALAT1 up-regulates ZNF217 expression by targeting miR-141-3p, thus enhances the activity of TGF-β2/SMAD2 signaling pathway and promotes wound healing process. This investigation shed new light on the understanding of the role of MALAT1 in wound healing, and may provide potential target for the diagnosis or therapy of chronic wounds.

Hyperbaric oxygen-induced long non-coding RNA MALAT1 exosomes suppress MicroRNA-92a expression in a rat model of acute myocardial infarction

Hyperbaric oxygen (HBO) improves angiogenesis. The effect of HBO on metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1), a pro‐angiogenic long non‐coding RNA, in cardiac myocyte‐derived exosomes and acute myocardial infarction (AMI) is unknown. We aimed to investigate whether MALAT1 is altered in cardiac myocyte‐derived exosomes in response to HBO as well as the molecular regulatory mechanisms of MALAT1 in cardiac myocytes treated with HBO. Cardiac myocytes were cultured, and HBO was applied at 2.5 atmosphere absolute in a hyperbaric chamber. Exosomes were extracted from the culture media. A rat model of AMI generated by the ligation of the left anterior descending artery was used. HBO significantly increased MALAT1 expression in cardiac myocytes and HBO‐induced MALAT1 and exosomes attenuated miR‐92a expression after myocardial infarction. Expression of krüppel‐like factor 2 (KLF2) and CD31 was significantly decreased after infarction and HBO‐induced exosomes significantly reversed the expression. Silencing of MALAT1 using MALAT1‐locked nucleic acid GapmeR significantly attenuated KLF2 and CD31 protein expression after infarction induced by HBO‐induced exosomes. HBO‐induced exosomes also decreased infarct size significantly. HBO‐induced exosomes from cardiac myocytes up‐regulate MALAT1 to suppress miR‐92a expression and counteract the inhibitory effect of miR‐92a on KLF2 and CD31 expression in left ventricular myocardium after myocardial infarction to enhance neovascularization.

Non-Coding RNAs in the Brain-Heart Axis: The Case of Parkinson's Disease

Parkinson's disease (PD) is a complex and heterogeneous disorder involving multiple genetic and environmental influences. Although a wide range of PD risk factors and clinical markers for the symptomatic motor stage of the disease have been identified, there are still no reliable biomarkers available for the early pre-motor phase of PD and for predicting disease progression. High-throughput RNA-based biomarker profiling and modeling may provide a means to exploit the joint information content from a multitude of markers to derive diagnostic and prognostic signatures. In the field of PD biomarker research, currently, no clinically validated RNA-based biomarker models are available, but previous studies reported several significantly disease-associated changes in RNA abundances and activities in multiple human tissues and body fluids. Here, we review the current knowledge of the regulation and function of non-coding RNAs in PD, focusing on microRNAs, long non-coding RNAs, and circular RNAs. Since there is growing evidence for functional interactions between the heart and the brain, we discuss the benefits of studying the role of non-coding RNAs in organ interactions when deciphering the complex regulatory networks involved in PD progression. We finally review important concepts of harmonization and curation of high throughput datasets, and we discuss the potential of systems biomedicine to derive and evaluate RNA biomarker signatures from high-throughput expression data.

miR-145 attenuates cardiac fibrosis through the AKT/GSK-3β/β-catenin signaling pathway by directly targeting SOX9 in fibroblasts

Myocardial infarction (MI) will inevitably result in cardiac fibrosis. In this study, we investigated the effect of microRNA-145 (miR-145) and transcription factor sex-determining region Y box 9 (SOX9) in the production of cardiac fibrosis induced by MI. MI rat models were established by left anterior descending coronary artery (LAD) occlusion. Four weeks after LAD, the cardiac fibrosis level was assessed by Masson's trichrome staining. Cardiac fibroblasts (CFs) exposed to hypoxia were used to simulate MI-induced fibrosis. Flow cytometry, cell counting kit-8, and transwell assays were used to examine changes in CF apoptosis, proliferation, and migration, respectively. miR-145 expression was measured by quantitative real-time polymerase chain reaction. Immunofluorescence and Western blot analysis were performed to determine the relative expression of proteins. In comparison to the sham-operated group, the expression of miR-145 was significantly downregulated in the infarction peripheral area, whereas, SOX9 was upregulated. In the infarcted heart, the overexpression of miR-145 significantly ameliorated cardiac fibrosis and cardiac function, and there was a negative correlation between miR-145 and SOX9 expressions in hypoxic CFs in vitro. In addition, SOX9 was verified to be a functional target of miR-145. Overexpression of miR-145 or inhibition of SOX9 decreased CF proliferation, migration, and fibrosis, but augmented their apoptotic rate. Moreover, the upregulation of miR-145 or suppression of SOX9 inhibited AKT and β-catenin signaling in hypoxic CFs. Taken together, this study highlights a potential treatment for cardiac fibrosis through the targeted regulation of SOX9 by miR-145, and our findings indicate that miR-145 exerts anti-fibrotic effects in MI via the negative regulation of SOX9 and its downstream AKT/GSK-3β/β-catenin pathways.