MicroRNA-26a protects against cardiac hypertrophy via inhibiting GATA4 in rat model and cultured cardiomyocytes

MicroRNA-322-5p targeting Smurf2 regulates the TGF-β/Smad pathway to protect cardiac function and inhibit myocardial infarction

Acute coronary artery blockage leads to acute myocardial infarction (AMI). Cardiomyocytes are terminally differentiated cells that rarely divide. Treatments preventing cardiomyocyte loss during AMI have a high therapeutic benefit. Accumulating evidence shows that microRNAs (miRNAs) may play an essential role in cardiovascular diseases. This study aims to explore the biological function and underlying regulatory molecular mechanism of miR-322-5p on myocardial infarction (MI). This study's miR-322-5p is downregulated in MI-injured hearts according to integrative bioinformatics and experimental analyses. In the MI rat model, miR-322-5p overexpression partially eliminated MI-induced changes in myocardial enzymes and oxidative stress markers, improved MI-caused impairment on cardiac functions, inhibited myocardial apoptosis, attenuated MI-caused alterations in TGF-β, p-Smad2, p-Smad4, and Smad7 protein levels. In oxygen-glucose deprivation (OGD)-injured H9c2 cells, miR-322-5p overexpression partially rescued OGD-inhibited cell viability and attenuated OGD-caused alterations in the TGF-β/Smad signaling. miR-322-5p directly targeted Smurf2 and inhibited Smurf2 expression. In OGD-injured H9c2 cells, Smurf2 knockdown exerted similar effects to miR-322-5p overexpression upon cell viability and TGF-β/Smad signaling; moreover, Smurf2 knockdown partially attenuated miR-322-5p inhibition effects on OGD-injured H9c2 cells. In conclusion, miR-322-5p is downregulated in MI rat heart and OGD-stimulated rat cardiomyocytes; the miR-322-5p/Smurf2 axis improves OGD-inhibited cardiomyocyte cell viability and MI-induced cardiac injuries and dysfunction through the TGF-β/Smad signaling.

DEC1 represses cardiomyocyte hypertrophy by recruiting PRP19 as an E3 ligase to promote ubiquitination-proteasome-mediated degradation of GATA4

Although the pro-hypertrophic role of GATA binding protein 4 (GATA4) during cardiac hypertrophy has been well established, the negative regulatory mechanism to counteract its hyperactivation remains elusive. We hypothesized that the hyperactivation of GATA4 could be a result of loss of interaction between GATA4 with specific suppressors. Using high throughput mass spectrometry technology, we carried out a proteomic screen for endogenous suppressor of GATA4, which disassociated with GATA4 during the hypertrophic response in a cultured cardiac myoblast cell line (H9C2 cells). We identified differentiated embryo chondrocyte 1 (DEC1) negatively regulated the function of GATA4 through physical interaction and negatively regulated cardiac hypertrophy both in vivo and in vitro. Particularly, DEC1 promoted the ubiquitination and proteasome-mediated degradation of GATA4, but did not function as an E3 ligase. Again, using mass spectrometry technology, we systematically identified pre-mRNA processing factor 19 (PRP19) as a newfound E3 ligase, which promoted the K6-linked ubiquitination of GATA4 at its lysine 256. Functional experiments performed in cultured neonatal rat ventricular myocytes and H9C2 cells demonstrated that both DEC1 and PRP19 negatively regulated agonist-induced cardiomyocyte hypertrophic responses. Furthermore, rescue experiments performed in these cells revealed that DEC1 and PRP19 suppressed cardiomyocyte hypertrophy by inhibiting the function of GATA4. Our study thus defined the novel DEC1-PRP19-GATA4 axis to be a previously unknown mechanism in regulating cardiomyocyte hypertrophy. Although GATA4 is indispensable for normal cardiac function, harnessing DEC1- or PRP19-mediated negative regulation to counteract the hyperactivation of GATA4 might serve as a novel therapeutic strategy for pathological cardiac hypertrophy.

Autophagy Regulation by Crosstalk between miRNAs and Ubiquitination System

MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules encoded by endogenous genes with ~22 nucleotides which are involved in the regulation of post-transcriptional gene expression. Ubiquitination and deubiquitination are common post-translational modifications in eukaryotic cells and important pathways in regulating protein degradation and signal transduction, in which E3 ubiquitin ligases and deubiquitinases (DUBs) play a decisive role. MiRNA and ubiquitination are involved in the regulation of most biological processes, including autophagy. Furthermore, in recent years, the direct interaction between miRNA and E3 ubiquitin ligases or deubiquitinases has attracted much attention, and the cross-talk between miRNA and ubiquitination system has been proved to play key regulatory roles in a variety of diseases. In this review, we summarized the advances in autophagy regulation by crosstalk between miRNA and E3 ubiquitin ligases or deubiquitinases.

MicroRNAs-The Heart of Post-Myocardial Infarction Remodeling

Myocardial infarction (MI) is one of the most frequent cardiac emergencies, with significant potential for mortality. One of the major challenges of the post-MI healing response is that replacement fibrosis could lead to left ventricular remodeling (LVR) and heart failure (HF). This process involves canonical and non-canonical transforming growth factor-beta (TGF-β) signaling pathways translating into an intricate activation of cardiac fibroblasts and disproportionate collagen synthesis. Accumulating evidence has indicated that microRNAs (miRNAs) significantly contribute to the modulation of these signaling pathways. This review summarizes the recent updates regarding the molecular mechanisms underlying the role of the over 30 miRNAs involved in post-MI LVR. In addition, we compare the contradictory roles of several multifunctional miRNAs and highlight their potential use in pressure overload and ischemia-induced fibrosis. Finally, we discuss their attractive role as prognostic biomarkers for HF, highlighting the most relevant human trials involving these miRNAs.

MiR-26a-5p alleviates cardiac hypertrophy and dysfunction via targeting ADAM17

Cardiac hypertrophy has been a high prevalence rate throughout the world. It has posed a big threat to public health due to limited therapeutic approaches. Previous studies showed that pathological cardiac hypertrophy was associated with autophagy, microRNAs (miRNA), and other signaling pathways, while the molecular mechanisms remain incompletely characterized. In this study, we used thoracic aortic constriction (TAC)-induced mice and angiotensin-II (Ang-II)-induced H9C2 cell line as cardiac hypertrophy model to investigate the role of miR-26a-5p in cardiac hypertrophy. We found that miR-26a-5p was downregulated in cardiac hypertrophy mice. Overexpression of miR-26a-5p by type 9 recombinant adeno-associated virus (rAAV9) reversed the heart hypertrophic manifestations. The phenotypes were also promoted by miR-26a-5p inhibitor in Ang-II-induced H9C2 cells. Through miRNA profile analysis and dual-luciferase reporter assay, ADAM17 was identified as a direct target of miR-26a-5p. Restored expression of ADAM17 disrupted the effect of miR-26a-5p on cardiac hypertrophy. To sum up, these results indicated that miR-26a-5p played an inhibitory role in cardiac hypertrophy and dysfunction via targeting ADAM17. The miR-26a-5p-ADAM17-cardiac hypertrophy axis provided special insight and a new molecular mechanism for a better understanding of cardiac hypertrophy disease, as well as the diagnostic and therapeutic practice.

Differential Spatio-Temporal Regulation of T-Box Gene Expression by microRNAs during Cardiac Development

Cardiovascular development is a complex process that starts with the formation of symmetrically located precardiac mesodermal precursors soon after gastrulation and is completed with the formation of a four-chambered heart with distinct inlet and outlet connections. Multiple transcriptional inputs are required to provide adequate regional identity to the forming atrial and ventricular chambers as well as their flanking regions; i.e., inflow tract, atrioventricular canal, and outflow tract. In this context, regional chamber identity is widely governed by regional activation of distinct T-box family members. Over the last decade, novel layers of gene regulatory mechanisms have been discovered with the identification of non-coding RNAs. microRNAs represent the most well-studied subcategory among short non-coding RNAs. In this study, we sought to investigate the functional role of distinct microRNAs that are predicted to target T-box family members. Our data demonstrated a highly dynamic expression of distinct microRNAs and T-box family members during cardiogenesis, revealing a relatively large subset of complementary and similar microRNA-mRNA expression profiles. Over-expression analyses demonstrated that a given microRNA can distinctly regulate the same T-box family member in distinct cardiac regions and within distinct temporal frameworks, supporting the notion of indirect regulatory mechanisms, and dual luciferase assays on Tbx2, Tbx3 and Tbx5 3' UTR further supported this notion. Overall, our data demonstrated a highly dynamic microRNA and T-box family members expression during cardiogenesis and supported the notion that such microRNAs indirectly regulate the T-box family members in a tissue- and time-dependent manner.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.

Circular RNA circRNA_000203 aggravates cardiac hypertrophy via suppressing miR-26b-5p and miR-140-3p binding to Gata4

Aims

Circular RNAs (circRNAs) are involved in gene regulation in a variety of physiological and pathological processes. The present study aimed to investigate the effect of circRNA_000203 on cardiac hypertrophy and the potential mechanisms involved.

Methods and results

CircRNA_000203 was found to be up-regulated in the myocardium of Ang-II-infused mice and in the cytoplasma of Ang-II-treated neonatal mouse ventricular cardiomyocytes (NMVCs). Enforced expression of circRNA_000203 enhances cell size and expression of atrial natriuretic peptide and β-myosin heavy chain in NMVCs. In vivo, heart function was impaired and cardiac hypertrophy was aggravated in Ang-II-infused myocardium-specific circRNA_000203 transgenic mice (Tg-circ203). Mechanistically, we found that circRNA_000203 could specifically sponge miR-26b-5p, -140-3p in NMVCs. Further, dual-luciferase reporter assay showed that miR-26b-5p, -140-3p could interact with 3′-UTRs of Gata4 gene, and circRNA_000203 could block the above interactions. In addition, Gata4 expression is transcriptionally inhibited by miR-26b-5p, -140-3p mimic in NMVCs but enhanced by over-expression of circRNA_000203 in vitro and in vivo. Functionally, miR-26b-5p, -140-3p, and Gata4 siRNA, could reverse the hypertrophic growth in Ang-II-induced NMVCs, as well as eliminate the pro-hypertrophic effect of circRNA_000203 in NMVCs. Furthermore, we demonstrated that NF-κB signalling mediates the up-regulation of circRNA_000203 in NMVCs exposed to Ang-II treatment.

Conclusions

Our data demonstrated that circRNA_000203 exacerbates cardiac hypertrophy via suppressing miR-26b-5p and miR-140-3p leading to enhanced Gata4 levels.

New Insights and Current Approaches in Cardiac Hypertrophy Cell Culture, Tissue Engineering Models, and Novel Pathways Involving Non-Coding RNA

Cardiac hypertrophy is an ongoing clinical challenge, as risk factors such as obesity, smoking and increasing age become more widespread, which lead to an increasing prevalence of developing hypertrophy. Pathological hypertrophy is a maladaptive response to stress conditions, such as pressure overload, and involve a number of changes in cellular mechanisms, gene expression and pathway regulations. Although several important pathways involved in the remodeling and hypertrophy process have been identified, further research is needed to achieve a better understanding and explore new and better treatment options. More recently discovered pathways showed the involvement of several non-coding RNAs, including micro RNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), which either promote or inhibit the remodeling process and pose a possible target for novel therapy approaches. In vitro modeling serves as a vital tool for this further pathway analysis and treatment testing and has vastly improved over the recent years, providing a less costly and labor-intensive alternative to in vivo animal models.

Molecular Mechanisms of Action of Emodin: As an Anti-Cardiovascular Disease Drug

Emodin is a natural occurring anthraquinone derivative isolated from roots and barks of numerous plants, molds, and lichens. It is found to be an active ingredient in different Chinese herbs including Rheum palmatum and Polygonam multiflorum, and it is a pleiotropic molecule with diuretic, vasorelaxant, anti-bacterial, anti-viral, anti-ulcerogenic, anti-inflammatory, and anti-cancer effects. Moreover, emodin has also been shown to have a wide activity of anti-cardiovascular diseases. It is mainly involved in multiple molecular targets such as inflammatory, anti-apoptosis, anti-hypertrophy, anti-fibrosis, anti-oxidative damage, abnormal, and excessive proliferation of smooth muscle cells in cardiovascular diseases. As a new type of cardiovascular disease treatment drug, emodin has broad application prospects. However, a large amount of evidences detailing the effect of emodin on many signaling pathways and cellular functions in cardiovascular disease, the overall understanding of its mechanisms of action remains elusive. In addition, by describing the evidence of the effects of emodin in detail, the toxicity and poor oral bioavailability of mice have been continuously discovered. This review aims to describe a timely overview of emodin related to the treatment of cardiovascular disease. The emphasis is to summarize the pharmacological effects of emodin as an anti-cardiovascular drug, as well as the targets and its potential mechanisms. Furthermore, the treatment of emodin compared with conventional cardiovascular drugs or target inhibitors, the toxicity, pharmacokinetics and derivatives of emodin were discussed.

MiR-21, MiR-29a, GATA4, and MEF2c Expression Changes in Endothelin-1 and Angiotensin II Cardiac Hypertrophy Stimulated Isl-1+Sca-1+c-kit+ Porcine Cardiac Progenitor Cells In Vitro

Cost- and time-intensive porcine translational disease models offer great opportunities to test drugs and therapies for pathological cardiac hypertrophy and can be supported by porcine cell culture models that provide further insights into basic disease mechanisms. Cardiac progenitor cells (CPCs) residing in the adult heart have been shown to differentiate in vitro into cardiomyocytes and could contribute to cardiac regeneration. Therefore, it is important to evaluate their changes on the cellular level caused by disease. We successfully isolated Isl1⁺Sca1⁺cKit⁺ porcine CPCs (pCPCs) from pig hearts and stimulated them with endothelin-1 (ET-1) and angiotensin II (Ang II) in vitro. We also performed a cardiac reprogramming transfection and tested the same conditions. Our results show that undifferentiated Isl1⁺Sca1⁺cKit⁺ pCPCs were significantly upregulated in GATA4, MEF2c, and miR-29a gene expressions and in BNP and MCP-1 protein expressions with Ang II stimulation, but they showed no significant changes in miR-29a and MCP-1 when stimulated with ET-1. Differentiated Isl1⁺Sca1⁺cKit⁺ pCPCs exhibited significantly higher levels of MEF2c, GATA4, miR-29a, and miR-21 as well as Cx43 and BNP with Ang II stimulation. pMx-MGT-transfected Isl1⁺Sca1⁺cKit⁺ pCPCs showed significant elevations in MEF2c, GATA4, and BNP expressions when stimulated with ET-1. Our model demonstrates that in vitro stimulation leads to successful Isl1⁺Sca1⁺cKit⁺ pCPC hypertrophy with upregulation of cardiac remodeling associated genes and profibrotic miRNAs and offers great possibilities for further investigations of disease mechanisms and treatment.

LncRNA 2810403D21Rik/Mirf promotes ischemic myocardial injury by regulating autophagy through targeting Mir26a

More evidence is emerging of the roles long non-coding RNAs (lncRNAs) play as regulatory factors in a variety of biological processes, but the mechanisms underlying the function of lncRNAs in acute myocardial infarction (AMI) have not been explicitly delineated. The present study identified the lncRNA 2810403D21Rik/AK007586/Mirf (myocardial infarction-regulatory factor), that inhibited macroautophagy/autophagy by modulating Mir26a (microRNA 26a). Inhibition of Mir26a led to cardiac injury both in vitro and in vivo, whereas overexpression of Mir26a attenuated ischemic stress-induced cell death by activating autophagy through targeting Usp15 (ubiquitin specific peptidase 15). More importantly, 2810403D21Rik/Mirf acted as a competitive endogenous RNA (ceRNA) of Mir26a; forced expression of 2810403D21Rik/Mirf downregulated Mir26a to inhibit autophagy. In contrast, loss of 2810403D21Rik/Mirf resulted in upregulation of Mir26a to promote autophagy and alleviate cardiac injury, which in turn improved cardiac function in MI mice. This study identified a lncRNA 2810403D21Rik/Mirf that functions as an anti-autophagic molecule via ceRNA activity toward Mir26a. Our findings suggest that knockdown of 2810403D21Rik/Mirf might be a novel therapeutic approach for cardiac diseases associated with autophagy.

ABBREVIATIONS

3-MA: 3-methyladenine; AAV-9: adenovirus associated virus-9; agoMir26a: cholesterol-conjugated Mir26a mimic; AMI: acute myocardial infarction; AMO-26a: Mir26a inhibitor; ATG: autophagy related; BECN1: beclin 1; ceRNA: competitive endogenous RNAs; EF: ejection fraction; f-2810403D21Rik/Mirf: fragment encompassing the Mir26a binding site; FS: fraction shortening; GFP-mRFP: a plasmid expressing green fluorescent protein-monomeric red fluorescent protein; lncRNA: long non-coding RNA; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; Mirf: myocardial infarction-regulatory factor; miRNAs: microRNAs; NC: negative control; NMCMs: neonatal mice cardiomyocytes; shRNA: short hairpin RNA; siRNA: small interfering RNA; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy; Usp15: ubiquitin specific peptidase 15.

Retracted: Emodin protects H9c2 cells against hypoxia-induced injury via regulation of miR-26a/survivin and the JAK1/STAT3 pathway

BACKGROUND/AIM

Congenital heart disease (CHD) is a catastrophic disease. Emodin possesses biological properties in protecting against some diseases. Our study investigated to explore the effects of emodin on hypoxia-stimulated cardiomyocytes, which mimicked CHD in vitro.

METHODS

H9c2 cells were stimulated with hypoxia and then the cells were treated with or without emodin, and/or transfected with miR-26a mimic, pcDNA-survivin and their corresponding negative control (NC). Cell viability and cell apoptosis were detected by Cell Counting kit-8 assay and flow cytometry, respectively. In addition, the expression of apoptotic proteins, Janus kinase 1 (JNK)/signal transducer and activator of transcription 3 (STAT3) pathway factors, and survivin were evaluated by using Western blot analysis. The expression of miR-26a was analyzed by quantitative real time polymerase chain reaction (qRT-PCR). Moreover, the target of miR-26a was verified by using a luciferase report assay.

RESULTS

Hypoxia significantly decreased cell viability and increased cell apoptosis, and the accumulated levels of cleaved caspase-3 and cleaved-caspase-9 were upregulated by hypoxia compared with the control. However, emodin administration led to the opposite result. A further result showed that emodin increased the phosphorylation of JNK/STAT3 pathway-related proteins and the pathway inhibitor AG490 impaired the protective effects of emodin on hypoxia-induced injury. In addition, emodin negatively regulated the miR-26a expression, and overexpression of miR-26a enhanced cell apoptosis and upregulated the expression of cleaved-caspase-3 and cleaved-caspase-9 compared with the NC. Moreover, emodin statistically upregulated the expression of survivin, and overexpression of miR-26a decreased the expression of survivin. The luciferase of miR-26a overexpression was decreased in the wild type of the survivin group.

CONCLUSION

Emodin protects hypoxia-induced cell injury as evidenced by increasing cell viability and decreasing apoptosis through downregulation of miR-26a as well as activation of the JNK/STAT3 pathway.

microRNA-26a-5p affects myocardial injury induced by coronary microembolization by modulating HMGA1

Coronary microembolization (CME) occurs when atherosclerotic plaque debris is detached during the treatment of acute coronary syndrome with Percutaneous Coronary Intervention (PCI). The complications of distal microvascular embolism, including local myocardial inflammation, are the main causes of myocardial damage and are a strong predictor of poor long-term prognosis and major cardiac adverse events. microRNAs (miRNAs) are involved in the pathophysiological processes of cardiovascular inflammatory diseases. Dysregulation of microRNA (miR)-26a-5p, in particular, is associated with a variety of cardiovascular diseases. However, the role of miR-26a-5p in CME-induced myocardial injury is unclear. In this study, we developed an animal model of CME by injecting microembolic balls into the left ventricle of rats and found that miR-26a-5p expression decreased in myocardial tissue in response. Using a miR-26a-5p mimic, echocardiography, hematoxylin-eosin staining, and Western blot analysis we found that the diminished cardiac function and myocardial inflammation induced by CME is alleviated by miR-26a-5p overexpression. Furthermore, our results show that inhibitors of miR-26a-5p have the opposite effect. In addition, in vitro experiments using real-time PCR, Western blot analysis, and a dual luciferase reporter gene show that HMGA1 is a target gene of miR-26a-5p. Thus, overexpression of miR-26a-5p could be a novel therapy to improve CME-induced myocardial damage.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

Microtubule associated protein 4 phosphorylation leads to pathological cardiac remodeling in mice

Background

Cardiac remodeling is a pathophysiological process that involves various changes in heart, including cardiac hypertrophy and fibrosis. Cardiac remodeling following pathological stimuli is common trigger leading to cardiac maladaptation and onset of heart failure, and their pathogenesis remains unclear.

Methods

Heart specimens of tetralogy of Fallot (TOF) patients, myocardial infarction (MI) and transverse aortic constriction (TAC) mouse models were collected to determine changes of microtubule associated protein 4 (MAP4) phosphorylation. MAP4 (S667A, S737E and S760E) knock in (MAP4 KI) mouse and cultured neonatal mouse cardiomyocytes or fibroblasts were used to investigate changes of cardiac phenotypes and possible mechanisms with a variety of approaches, including functional, histocytological and pathological observations.

Findings

Elevated cardiac phosphorylation of MAP4 (S737 and S760) was observed in TOF patients, MI and TAC mouse models. In MAP4 KI mice, age-dependent cardiac phenotypes, including cardiac hypertrophy, fibrosis, diastolic and systolic dysfunction were observed. In addition, increased cardiomyocyte apoptosis together with microtubule disassembly and mitochondrial translocation of phosphorylated MAP4 was detected prior to the onset of cardiac remodeling, and p38/MAPK was demonstrated to be the possible signaling pathway that mediated MAP4 (S737 and S760) phosphorylation.

Interpretation

Our data reveal for the first time that MAP4 drives pathological cardiac remodeling through its phosphorylation. These findings bear the therapeutic potential to ameliorate pathological cardiac remodeling by attenuating MAP4 phosphorylation.

Fund

This work was supported by the Key Program of National Natural Science Foundation of China (No.81430042) and National Natural Science Foundation of China (No.81671913).

[Use of microRNAs in heart failure management]

Heart failure (HF) is a high impact disease that affects all human populations, demanding the development of new strategies and methods to manage this pathology. That's why microRNAs, small noncoding RNAs that regulate gene expression, appear as an important option in the diagnosis, prognosis and treatment of this disease. MiRNAs seems to have a future on HF handling, because can be isolated from body fluids such as blood, and changes in its levels can be associated with the presence, stage and specific disease features, which makes them an interesting option as biomarkers. Also, due to the important role of these molecules on regulation of gene expression and cell homeostasis, it has been explored its potential use as a therapeutic method to prevent or treat HF. That is why this review seeks to show the importance of biomedical research involving the use of miRNAs as a method to approach the HF, showing the impact of disease in the world, aspects of miRNAs biology, and their use as biomarkers and as important therapeutic targets.

Characterization and analysis of long non-coding rna (lncRNA) in In Vitro- and Ex Vivo-derived cardiac progenitor cells

Recent advancements in cell-based therapies for the treatment of cardiovascular disease (CVD) show continuing promise for the use of transplanted stem and cardiac progenitor cells (CPCs) to promote cardiac restitution. However, a detailed understanding of the molecular mechanisms that control the development of these cells remains incomplete and is critical for optimizing their use in such therapy. Long non-coding (lnc) RNA has recently emerged as a crucial class of regulatory molecules involved in directing a variety of critical biological processes including development, homeostasis and disease. As such, a rising body of evidence suggests that they also play key regulatory roles in CPC development, though many questions remain regarding the expression landscape and specific identity of lncRNA involved in this process. To address this, we performed whole transcriptome sequencing of two murine CPC populations–Nkx2-5 EmGFP reporter-sorted embryonic stem (ES) cell-derived and ex vivo, cardiosphere-derived–in an effort to characterize their lncRNA profiles and potentially identify novel CPC regulators. The resulting sequencing data revealed an enrichment in both CPC populations for a panel of previously-identified lncRNA genes associated with cardiac differentiation. Additionally, a total of 1,678 differentially expressed and as-of-yet unannotated, putative lncRNA genes were found to be enriched for in the two CPC populations relative to undifferentiated ES cells.

Downregulation of miR-200c protects cardiomyocytes from hypoxia-induced apoptosis by targeting GATA-4

Hypoxia-induced cardiomyocyte apoptosis plays an important role in the development of ischemic heart disease. MicroRNAs (miRNAs or miRs) are emerging as critical regulators of hypoxia-induced cardiomyocyte apoptosis. miR-200c is an miRNA that has been reported to be related to apoptosis in various pathological processes; however, its role in hypoxia‑induced cardiomyocyte apoptosis remains unclear. In the present study, we aimed to investigate the potential role and underlying mechanism of miR-200c in regulating hypoxia‑induced cardiomyocyte apoptosis. We found that miR-200c was significantly upregulated by hypoxia in cardiomyocytes, as detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The lactate dehydrogenase, MTT, Annexin V/propidium iodide apoptosis and caspase-3 activity assays showed that downregulation of miR-200c markedly improved cell survival and suppressed the apoptosis of cardiomyocytes in response to hypoxia. Bioinformatics analysis and the dual-luciferase reporter assay demonstrated that miR-200c directly targeted the 3'-untranslated region of GATA-4, an important transcription factor for cardiomyocyte survival. RT-qPCR and western blot analysis showed that suppression of miR-200c significantly increased GATA-4 expression. Furthermore, downregulation of miR-200c upregulated the expression of the anti-apoptotic gene Bcl-2. However, the protective effects against hypoxia induced by the downregulation of miR‑200c were significantly abolished by GATA-4 knockdown. Taken together, our results suggest that downregulation of miR-200c protects cardiomyocytes from hypoxia-induced apoptosis by targeting GATA-4, providing a potential therapeutic molecular target for the treatment of ischemic heart disease.

The Role and Molecular Mechanism of Non-Coding RNAs in Pathological Cardiac Remodeling

Non-coding RNAs (ncRNAs) are a class of RNA molecules that do not encode proteins. Studies show that ncRNAs are not only involved in cell proliferation, apoptosis, differentiation, metabolism and other physiological processes, but also involved in the pathogenesis of diseases. Cardiac remodeling is the main pathological basis of a variety of cardiovascular diseases. Many studies have shown that the occurrence and development of cardiac remodeling are closely related with the regulation of ncRNAs. Recent research of ncRNAs in heart disease has achieved rapid development. Thus, we summarize here the latest research progress and mainly the molecular mechanism of ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), in cardiac remodeling, aiming to look for new targets for heart disease treatment.

MiR-26a enhances invasive capacity by suppressing GSK3β in human lung cancer cells

Lung cancer is the common cause of death from cancer, and most lung cancer patients die of metastasis. MicroRNAs (miRNAs) function as either oncogenes or tumor suppressors, playing crucial role not only in tumorigenesis, but also in tumor invasion and metastasis. There are several studies showed that miR-26a is involved in carcinogenesis, however, its role in tumor metastasis need to be elucidated. In this study, we showed that ectopic expression of miR-26a enhanced migration and invasion of lung cancer cells. Glycogen synthase kinase-3β (GSK3β) was identified as a direct target of miR-26a. GSK3β expression negatively correlated with miR-26a expression in lung cancer tissues. Silencing of GSK3β achieved similar effect as miR-26a over-expression; over-expression of GSK3β reversed the enhanced effect of miR-26a on lung cancer cell migration and invasion. Further study indicated that miR-26a increased β-catenin expression and nuclear translocation. C-myc and cyclin D1, the downstream genes of β-catenin, were also up-regulated by miR-26a. Furthermore, xenograft study showed that miR-26a promoted lung cancer cell growth in vivo, and suppressed GSK3β expression. Collectively, our results demonstrated that miR-26a enhanced metastatic potential of lung cancer cells via activation of β-catenin pathway by targeting GSK3β, suggesting the potential applicability of miR-26a as a target for cancer treatment.