Long non-coding RNA MALAT1 regulates cardiomyocytes apoptosis after hypoxia/reperfusion injury via modulating miR-200a-3p/PDCD4 axis

Evidence and perspectives on miRNA, circRNA, and lncRNA in myocardial ischemia-reperfusion injury: a bibliometric study

OBJECTIVE

miRNA, circRNA, and lncRNA play crucial roles in the pathogenesis and progression of myocardial ischemia-reperfusion injury (MI/RI). This study aims to provide valuable insights into miRNA, circRNA, lncRNA, and MI/RI from a bibliometric standpoint, with the goal of fostering further advancements in this area.

METHODS

The relevant literature in the field of miRNA, circRNA, lncRNA, and MI/RI was retrieved from the Science Citation Index Expanded (SCI-E) database within Web of Science. The "Analyze Results" and "Citation Report" functions in WOS were utilized to compile the annual publication and citation counts in this field. Microsoft Office Excel 2019 was used to organize and visualize the data. Furthermore, bibliometric and visualization analyses of countries/regions, institutions, authors, keywords, and references were conducted using the bibliometric visualization software CiteSpace.

RESULTS

A total of 858 publications were included for further analysis in this field. The literature was published across 297 journals, with Molecular Medicine Reports contributing the highest number of publications. Researchers from 45 countries participated in studies within this field, with those from China contributing the most publications. The research hotspots in this field primarily focus on three areas: the role of miRNA, circRNA, and lncRNA in the pathogenesis of MI/RI, their potential as therapeutic targets, and their role as biomarkers. Among these, circular RNA, therapy target, inflammatory response, and cardiomyocyte ferroptosis are likely to emerge as emerging trends in this field.

CONCLUSION

The overall development of research in this field is on the rise. The compilation of research hotspots and emerging trends in this area may provide researchers with more references and assistance in selecting research directions, ultimately benefiting MI/RI patients.

LncRNA MALAT1 suppresses monocyte-endothelial cell interactions by targeting miR-30b-5p and enhancing ATG5-mediated autophagy

Background

Monocyte-endothelial cell (EC) interactions are one of the earliest events in the development of atherosclerosis and play a crucial role in atherosclerotic plaque formation. Although attempts have been made to modulate this interaction, the underlying molecular signalling mechanisms remain unclear. This study aimed to investigate the role of long non-coding RNA MALAT1 in monocyte-EC interactions.

Methods

The expression of MALAT1, ICAM-1, VCAM-1, P-selectin, CCL2 and CXCL1 was evaluated in ApoE-/- mouse aortic tissues and inflamed human umbilical vein endothelial cells (HUVECs). The regulatory impact of MALAT1 on cell adhesion molecules, monocyte-EC adhesion, and autophagy was assessed. The interactions between MALAT1 and microRNAs (miRNAs) were evaluated using dual-luciferase reporter and RNA pull-down assays.

Results

MALAT1 expression decreased in ApoE-/- mouse aortic tissues and inflammatory HUVECs. MALAT1 overexpression suppressed the expression of ICAM-1, VCAM-1 and CXCL1, and reduced the migration and adhesion of monocytes to ECs. Inhibition of MALAT1 promoted cell adhesion molecule expression and monocyte-EC interactions. Mechanistically, MALAT1 binds directly to miR-30b-5p and decreases its effective expression by functioning as an endogenous sponge, thereby increasing the expression of autophagy-related gene 5 (ATG5) and stimulates endothelial autophagy.

Conclusions

Our findings suggest that MALAT1 suppresses monocyte-EC interactions by targeting miR-30b-5p and enhancing ATG5-mediated endothelial autophagy. These data imply that MALAT1 may play a protective role at the early stages of the atherosclerotic process.

miR-200a-3p inhibits the PDGF-BB-induced proliferation of VSMCs by affecting their phenotype-associated proteins

Accumulating evidence shows that the abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) can significantly affect the long-term prognosis of coronary artery bypass grafting. This study aimed to explore the factors affecting the proliferation, migration, and phenotypic transformation of VSMCs. First, we stimulated VSMCs with different platelet-derived growth factor-BB (PDGF-BB) concentrations, analyzed the expression of phenotype-associated proteins by Western blotting, and examined cell proliferation by scratch wound healing and the 5-ethynyl-2-deoxyuridine (EdU) assay. VSMC proliferation was induced most by PDGF-BB treatment at 20 ng/mL. miR-200a-3p decreased significantly in A7r5 cells stimulated with PDGF-BB. The overexpression of miR-200a-3p reversed the downregulation of α-SMA (p < 0.001) and the upregulation of vimentin (p < 0.001) caused by PDGF-BB. CCK8 and EdU analyses showed that miR-200a-3p overexpression could inhibit PDGF-BB-induced cell proliferation (p < 0.001). However, flow cytometric analysis showed that it did not significantly increase cell apoptosis. Collectively, the overexpression of miR-200a-3p inhibited the proliferation and migration of VSMCs induced by PDGF-BB, partly by affecting phenotypic transformation-related proteins, providing a new strategy for relieving the restenosis of vein grafts.

Programmed cell death 4: A novel player in the pathogenesis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a pathological condition recognized by menstrual cycle irregularities, androgen excess, and polycystic ovarian morphology, affecting a significant proportion of women of childbearing age and accounting for the most prevalent cause of anovulatory sterility. In addition, PCOS is frequently accompanied by metabolic and endocrine disturbances such as obesity, dyslipidemia, insulin resistance, and hyperinsulinemia, indicating the multiplicity of mechanisms implicated in the progression of PCOS. However, the exact pathogenesis of PCOS is yet to be elucidated. Programmed cell death 4 (PDCD4) is a ubiquitously expressed protein that contributes to the regulation of various cellular processes, including gene expression, cell cycle progression, proliferation, and apoptosis. Despite some disparities concerning its exact cellular effects, PDCD4 is generally characterized as a protein that inhibits cell cycle progression and proliferation and instead drives the cell into apoptosis. The apoptosis of granulosa cells (GCs) is speculated to take a major part in the occurrence and progression of PCOS by ceasing antral follicle development and compromising oocyte competence. Given the possible involvement of GC apoptosis in the progression of PCOS, as well as the contribution of PDCD4 to the regulation of cell apoptosis and the development of metabolic diseases, the current review aimed to discuss whether or how PDCD4 can play a role in the pathogenesis of PCOS by affecting GC apoptosis.

Apoptosis and long non-coding RNAs: Focus on their roles in Heart diseases

Heart disease is one of the principal death reasons around the world and there is a growing requirement to discover novel healing targets that have the potential to avert or manage these illnesses. On the other hand, apoptosis is a strongly controlled, cell removal procedure that has a crucial part in numerous cardiac problems, such as reperfusion injury, MI (myocardial infarction), consecutive heart failure, and inflammation of myocardium. Completely comprehending the managing procedures of cell death signaling is critical as it is the primary factor that influences patient mortality and morbidity, owing to cardiomyocyte damage. Indeed, the prevention of heart cell death appears to be a viable treatment approach for heart illnesses. According to current researches, a number of long non-coding RNAs cause the heart cells death via different methods that are embroiled in controlling the activity of transcription elements, the pathways that signals transmission within cells, small miRNAs, and the constancy of proteins. When there is too much cell death in the heart, it can cause problems like reduced blood flow, heart damage after restoring blood flow, heart disease in diabetics, and changes in the heart after reduced blood flow. Therefore, studying how lncRNAs control apoptosis could help us find new treatments for heart diseases. In this review, we present recent discoveries about how lncRNAs are involved in causing cell death in different cardiovascular diseases.

Inhibiting microRNA-200a-3p attenuates pyroptosis via targeting the SIRT1/NF-κB/NLRP3 pathway in H2O2-induced HAEC

Atherosclerosis is a chronic inflammatory disease of the arterial wall caused by many factors. Endothelial cell dysfunction is the initial factor in the development of atherosclerosis, and ROS activates the assembly of inflammasomes and induces the pyroptosis of vascular endothelial cells. Whether H2O2 induced human aortic endothelial cells (HAECs) pyroptosis and the underlying mechanisms remain unclear. This study aimed to investigate the role of microRNA-200a-3p in H2O2-induced HAECs pyroptosis. First, we found that the pyroptosis-related protein was upregulated in aortia in HFD apoE-/- mice. The in vitro study showed that the activation of NLRP3 inflammasomes and the pyroptosis in H2O2-induced HAECs, which is characterized by an increase in Lactate dehydrogenase (LDH) activity, and an increase in propidium iodide (PI)-positive cells. The expression of silent information regulator of transcription 1 (SIRT1) was also decreased in H2O2-induced HAECs, and the overexpression of SIRT1 could reverse the occurrence of pyroptosis, partly through p65 deacetylation, thereby inhibiting nuclear translocation of p65 and regulating NLRP3 expression. Further studies revealed increased miRNA-200a-3p expression in H2O2-induced HAECs and the promotion of pyroptosis, which was achieved by targeting SIRT1. Inhibition of miR-200a-3p reduced pyroptosis by promoting the expression of the downstream target gene SIRT1 and reducing the accumulation of p65 and NLRP3. Collectively, our results suggest that H2O2 can regulate NLRP3 inflammasomes through the miR-200a-3p/SIRT1/NF-κB (p65) signaling pathway and promote HAEC pyroptosis. The miR-200a-3p inhibitor can promote the expression of SIRT1 and inhibit pyroptosis, which may be important to prevent and treat atherosclerosis.

miR-200a-3p overexpression alleviates diabetic cardiomyopathy injury in mice by regulating autophagy through the FOXO3/Mst1/Sirt3/AMPK axis

Objective

Hyperglycemia and insulin resistance or deficiency are characteristic features of diabetes. Diabetes is accompanied by cardiomyocyte hypertrophy, fibrosis and ventricular remodeling, and eventually heart failure. In this study, we established a diabetic cardiomyopathy (DCM) mouse model to explore the role and mechanism of miR-200a-3p in DCM.

Methods

We used db/db mice to simulate the animal model of DCM and the expression of miR-200a-3p was then examined by RT-qPCR. Tail vein injection of mice was done with rAAV-miR-200a-3p for 8 weeks, and cardiac function was assessed by cardiac ultrasound. The levels of myocardial tissue injury, fibrosis, inflammation, apoptosis and autophagy in mice were detected by histological staining, TUNEL and other molecular biological experiments.

Results

miR-200a-3p expression levels were significantly decreased in the myocardium of DCM mice. Diabetic mice developed cardiac dysfunction and presented pathological changes such as myocardial injury, myocardial interstitial fibrosis, cardiomyocyte apoptosis, autophagy, and inflammation. Overexpression of miR-200a-3p expression significantly ameliorated diabetes induced-cardiac dysfunction and myocardial injury, myocardial interstitial fibrosis, cardiomyocyte apoptosis, and inflammation, and enhanced autophagy. Mechanistically, miR-200a-3p interacted with FOXO3 to promote Mst1 expression and reduce Sirt3 and p-AMPK expression.

Conclusion

In type 2 diabetes, increased miR-200a-3p expression enhanced autophagy and participated in the pathogenic process of cardiomyopathy throug7 Mst1/Sirt3/AMPK axis regulation by its target gene FOXO3. This conclusion provides clues for the search of new gene targeted therapeutic approaches for diabetic cardiomyopathy.

MALAT1/miR-185-5p mediated high glucose-induced oxidative stress, mitochondrial injury and cardiomyocyte apoptosis via the RhoA/ROCK pathway

To explore the underlying mechanism of lncRNA MALAT1 in the pathogenesis of diabetic cardiomyopathy (DCM). DCM models were confirmed in db/db mice. MiRNAs in myocardium were detected by miRNA sequencing. The interactions of miR-185-5p with MALAT1 and RhoA were validated by dual-luciferase reporter assays. Primary neonatal cardiomyocytes were cultured with 5.5 or 30 mmol/L D-glucose (HG) in the presence or absence of MALAT1-shRNA and fasudil, a ROCK inhibitor. MALAT1 and miR-185-5p expression were determined by real-time quantitative PCR. The apoptotic cardiomyocytes were evaluated using flow cytometry and TUNEL staining. SOD activity and MDA contents were measured. The ROCK activity, phosphorylation of Drp1S616 , mitofusin 2 and apoptosis-related proteins were analysed by Western blotting. Mitochondrial membrane potential was examined by JC-1. MALAT1 was significantly up-regulated while miR-185-5p was down-regulated in myocardium of db/db mice and HG-induced cardiomyocytes. MALAT1 regulated RhoA/ROCK pathway via sponging miR-185-5p in cardiomyocytes in HG. Knockdown of MALAT1 and fasudil all inhibited HG-induced oxidative stress, and alleviated imbalance of mitochondrial dynamics and mitochondrial dysfunction, accompanied by reduced cardiomyocyte apoptosis. MALAT1 activated the RhoA/ROCK pathway via sponging miR-185-5p and mediated HG-induced oxidative stress, mitochondrial damage and apoptosis of cardiomyocytes in mice.

miRNAs Epigenetic Tuning of Wall Remodeling in the Early Phase after Myocardial Infarction: A Novel Epidrug Approach

Myocardial infarction (MI) is one of the leading causes of death in Western countries. An early diagnosis decreases subsequent severe complications such as wall remodeling or heart failure and improves treatments and interventions. Novel therapeutic targets have been recognized and, together with the development of direct and indirect epidrugs, the role of non-coding RNAs (ncRNAs) yields great expectancy. ncRNAs are a group of RNAs not translated into a product and, among them, microRNAs (miRNAs) are the most investigated subgroup since they are involved in several pathological processes related to MI and post-MI phases such as inflammation, apoptosis, angiogenesis, and fibrosis. These processes and pathways are finely tuned by miRNAs via complex mechanisms. We are at the beginning of the investigation and the main paths are still underexplored. In this review, we provide a comprehensive discussion of the recent findings on epigenetic changes involved in the first phases after MI as well as on the role of the several miRNAs. We focused on miRNAs function and on their relationship with key molecules and cells involved in healing processes after an ischemic accident, while also giving insight into the discrepancy between males and females in the prognosis of cardiovascular diseases.

CircHECTD1 promoted MIRI-associated inflammation via inhibiting miR-138-5p and upregulating ROCK2

Myocardial ischemia-reperfusion injury (MIRI) was often observed after surgeries, causing a lot of suffering to patients. Inflammation and apoptosis were critical determinants during MIRI. We conveyed experiments to reveal the regulatory functions of circHECTD1 in MIRI development. The Rat MIRI model was established and determined by 2,3,5-triphenyl tetrazolium chloride (TTC) staining. We analyzed cell apoptosis using TUNEL and flow cytometry. Proteins expression was evaluated by western blot. The RNA level was determined by qRT-PCR. Secreted inflammatory factors were analyzed by ELISA assay. To predict the interaction sequences on circHECTD1, miR-138-5p, and ROCK2, bioinformatics analysis was performed. Dual-luciferase assay was used to confirm these interaction sequences. CircHECTD1 and ROCK2 were upregulated in the rat MIRI model, while miR-138-5p was decreased. CircHECTD1 knockdown alleviated H/R-induced inflammation in H9c2 cells. Direct interaction and regulation of circHECTD1/miR-138-5p and miR-138-5p/ROCK2 were confirmed by dual-luciferase assay. CircHECTD1 promoted H/R-induced inflammation and cell apoptosis by inhibiting miR-138-5p. miR-138-5p alleviated H/R-induced inflammation, while ectopic ROCK2 antagonized such effect of miR-138-5p. Our research suggested that the circHECTD1-modulated miR-138-5p suppressing is responsible for ROCK2 activation during H/R-induced inflammatory response, providing a novel insight into MIRI-associated inflammation.

Inhibition of miR-214-3p attenuates ferroptosis in myocardial infarction via regulating ME2

Myocardial infarction (MI) contributes to an increased risk of incident heart failure and sudden death, but there is still a lack of effective treatment in clinic. Recently, growing evidence has indicated that abnormal expression of microRNAs (miRNAs) plays a crucial role in cardiovascular diseases. In this research, the involvement of miRNA-214-3p in MI was explored. A mouse model of MI was established by ligation of the left anterior descending coronary artery, and primary cultures of neonatal rat cardiomyocytes (NRCMs) were submitted to hypoxic treatment to stimulate cellular injury in vitro. Our results showed that miR-214-3p level was significantly upregulated in the infarcted region of mouse hearts and in NRCMs exposed to hypoxia, accompanying with an obvious elevation of ferroptosis. Inhibition of miR-214-3p by antagomir injection improved cardiac function, decreased infarct size, and attenuated iron accumulation and oxidant stress in myocardial tissues. MiR-214-3p could also promote ferroptosis and cellular impairments in NRCMs, while miR-214-3p inhibitor effectively protected cells from hypoxia. Furthermore, dual luciferase reporter gene assay revealed that malic enzyme 2 (ME2) is a direct target of miR-214-3p. In cardiomyocytes, overexpression of ME2 ameliorated the detrimental effects and excessive ferroptosis induced by miR-214-3p mimic, whereas ME2 depletion compromised the protective role of miR-214-3p inhibitor against hypoxic injury and ferroptosis. These findings suggest that miR-214-3p contributes to enhanced ferroptosis during MI at least partially via suppressing ME2. Inhibition of miR-214-3p may be a new approach for tackling MI.

Long non-coding RNA MALAT1 protects against Aβ1-42 induced toxicity by regulating the expression of receptor tyrosine kinase EPHA2 via quenching miR-200a/26a/26b in Alzheimer's disease

Altered expressions of Receptor Tyrosine Kinases (RTK) and non-coding (nc) RNAs are known to regulate the pathophysiology of Alzheimer's disease (AD). However, specific understanding of the roles played, especially the mechanistic and functional roles, by long ncRNAs in AD is still elusive. Using mouse tissue qPCR assays we observe changes in the expression levels of 41 lncRNAs in AD mice of which only 7 genes happen to have both human orthologs and AD associations. Post validation of these 7 human lncRNA genes, MEG3 and MALAT1 shows consistent and significant decrease in AD cell, animal models and human AD brain tissues, but MALAT1 showed a more pronounced decrease. Using bioinformatics, qRT-PCR, RNA FISH and RIP techniques, we could establish MALAT1 as an interactor and regulator of miRs-200a, -26a and -26b, all of which are naturally elevated in AD. We could further show that these miRNAs target the RTK EPHA2 and several of its downstream effectors. Expectedly EPHA2 over expression protects against Aβ1-42 induced cytotoxicity. Transiently knocking down MALAT1 validates these unique regulatory facets of AD at the miRNA and protein levels. Although the idea of sponging of miRNAs by lncRNAs in other pathologies is gradually gaining credibility, this novel MALAT1- miR-200a/26a/26b - EPHA2 regulation mechanism in the context of AD pathophysiology promises to become a significant strategy in controlling the disease.

Change of Heart: the Epitranscriptome of Small Non-coding RNAs in Heart Failure

Purpose of Review

Small non-coding RNAs regulate gene expression and are highly implicated in heart failure. Recently, an additional level of post-transcriptional regulation has been identified, referred to as the epitranscriptome, which encompasses the body of post-transcriptional modifications that are placed on RNA molecules. In this review, we summarize the current knowledge on the small non-coding RNA epitranscriptome in heart failure.

Recent Findings

With the rise of new methods to study RNA modifications, epitranscriptome research has begun to take flight. Over the past 3 years, the number of publications on the epitranscriptome in heart failure has significantly increased, and we expect many more highly relevant publications to come out over the next few years.

Summary

Currently, at least six modifications on small non-coding RNAs have been investigated in heart failure-relevant studies, namely N6-adenosine, N5-cytosine and N7-guanosine methylation, 2’-O-ribose-methylation, adenosine-to-inosine editing, and isomiRs. Their potential role in heart failure is discussed.

MIR22HG Aggravates Oxygen-Glucose Deprivation and Reoxygenation-Induced Cardiomyocyte Injury through the miR-9-3p/SH2B3 Axis

Reperfusion therapy, the standard treatment for acute myocardial infarction (MI), can trigger necrotic death of cardiomyocytes and provoke ischemia/reperfusion (I/R) injury. However, molecular mechanisms that regulate cardiomyocyte death remain largely unknown. The abnormal expression of lncRNA MIR22HG has been found in types of diseases. The current study was aimed at exploring the function and mechanism of MIR22HG in I/R injury. In this study, mouse myocardial cells (HL-1) treated with oxygen-glucose deprivation and reoxygenation (OGD/R) were used as the in vitro models, and myocardial ischemia reperfusion injury (MIRI) animal models in vivo were established in male C57BL/6 mice. Experiments including CCK-8, flow cytometry, TUNEL, HE staining, RT-qPCR, western blotting, and luciferase reporter assays were performed to explore the function and potential mechanism of MIR22HG in MIRI in vitro and in vivo. Bioinformatics analysis was performed to predict the binding site between miR-9-3p and MIR22HG (or SH2B3). Our results indicated that the MIR22HG level was upregulated in cardiomyocytes after OGD/R treatment. The knockdown of MIR22HG promoted cell viability and inhibited apoptosis and extracellular matrix (ECM) production in OGD/R-treated HL-1 cells. In mechanism, MIR22HG binds to miR-9-3p, and miR-9-3p targets the SH2B3 3 ${}^{\prime }$ untranslated region (UTR). Moreover, SH2B3 expression was positively regulated by MIR22HG but negatively modulated by miR-9-3p. Rescue assays suggested that the suppressive effect of MIR22HG knockdown on cell viability, apoptosis, and ECM accumulation was reversed by the overexpression of SH2B3. The in vivo experiments demonstrated that MIR22HG knockdown alleviated cardiomyocyte apoptosis and reduced myocardial infarct size in MIRI mice. In summary, MIR22HG knockdown alleviates myocardial injury through the miR-9-3p/SH2B3 axis.

Long non-coding RNA MALAT1 aggravated liver ischemia-reperfusion injury via targeting miR-150-5p/AZIN1

Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays a crucial role in the process of renal ischemia-reperfusion (IR) injury and myocardial IR injury. However, its mechanism in liver IR injury is not clear. IR and hypoxia/reoxygenation (H/R) model were built on C57BL/6 mice. Blood samples were obtained from the inferior vena cava of the model mice. MALAT1 expression was detected in IR model and H/R model. Supported by experimental results, the impacts of MALAT1 on viability, apoptosis, and inflammation of H/R model cells were detected. The correlation between MALAT1 and downstream genes was analyzed by mechanism assays. MALAT1 was detected to be upregulated in IR model and H/R model. MALAT1 knockdown had inhibitory effects on apoptosis and inflammatory reaction while promoting liver cell viability in H/R condition. Meanwhile, MALAT1 targeted miR-150-5p to regulate antizyme inhibitor 1 (AZIN1) in liver cells. Finally, MALAT1 regulated viability, apoptosis, and inflammatory reaction of liver cells by targeting miR-150-5p and AZIN1. To conclude, MALAT1 targeted miR-150-5p/AZIN1 to accelerate liver IR injury, suggesting that MALAT1 might be a novel target for liver IR injury.

Interplay Between Non-Coding RNAs and Programmed Cell Death Proteins

Programmed cell death (PDCD) family of proteins includes at least 12 members, function of seven of them being more investigated. These members are PDCD1, PDCD2, PDCD4, PDCD5, PDCD6, PDCD7 and PDCD10. Consistent with the important roles of these proteins in the regulation of apoptosis, dysregulation of PDCDs is associated with diverse disorders ranging from intervertebral disc degeneration, amyotrophic lateral sclerosis, immune thrombocytopenia, type 1 diabetes, congenital hypothyroidism, Alzheimer’s disease to different types of cancers. More recently, the interaction between non-coding RNAs and different members of PDCD family is being discovered. In the current study, we described the functional interactions between PDCDs and two classes of non-coding RNAs, namely microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). miR-21 and miR-183 are two miRNAs whose interactions with PDCDs have been assessed in different contexts. The lncRNAs interaction with PDCDs is mainly assessed in the context of neoplasia indicating the role of MALAT1, MEG3, SNHG14 and LINC00473 in this process.

Protective effects of agrimonolide on hypoxia-induced H9c2 cell injury by maintaining mitochondrial homeostasis

Cardiomyocyte death caused by hypoxia is one of the main causes of myocardial infarction or heart failure, and mitochondria play an important role in this process. Agrimonolide (AM) is a monomeric component extracted from Agrimonia pilosa L. and has antioxidant, antitumor, and anti-inflammatory effects. This study aimed to investigate the role and mechanism of AM in improving hypoxia-induced H9c2 cell damage. The results showed that low AM concentrations promote H9c2 cell proliferation and increase cellular ATP content. Transcriptome sequencing showed that AM induces differential expression of genes in H9c2 cells. Gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that these genes were concentrated in mitochondrial function. Subsequent experiments confirmed that AM regulates hypoxia-induced cell cycle arrest. AM inhibited the rate of apoptosis by regulating the expression of apoptosis-related proteins, reducing the level of cleaved Caspase 3 and Bax, and increasing the level of Bcl2, thereby protecting H9c2 cells from hypoxia-induced apoptosis. AM restored the mitochondrial membrane potential, inhibited the generation of ROS, maintained the normal shape of the mitochondria, improved the level of the mitochondrial functional proteins OPA1, MFN1, MFN2, Tom20, and increased the level of ATP. In conclusion, AM protects H9c2 cells from hypoxia-induced cell damage.

Epitranscriptomics of cardiovascular diseases (Review)

RNA modifications have recently become the focus of attention due to their extensive regulatory effects in a vast array of cellular networks and signaling pathways. Just as epigenetics is responsible for the imprinting of environmental conditions on a genetic level, epitranscriptomics follows the same principle at the RNA level, but in a more dynamic and sensitive manner. Nevertheless, its impact in the field of cardiovascular disease (CVD) remains largely unexplored. CVD and its associated pathologies remain the leading cause of death in Western populations due to the limited regenerative capacity of the heart. As such, maintenance of cardiac homeostasis is paramount for its physiological function and its capacity to respond to environmental stimuli. In this context, epitranscriptomic modifications offer a novel and promising therapeutic avenue, based on the fine‑tuning of regulatory cascades, necessary for cardiac function. This review aimed to provide an overview of the most recent findings of key epitranscriptomic modifications in both coding and non‑coding RNAs. Additionally, the methods used for their detection and important associations with genetic variations in the context of CVD were summarized. Current knowledge on cardiac epitranscriptomics, albeit limited still, indicates that the impact of epitranscriptomic editing in the heart, in both physiological and pathological conditions, holds untapped potential for the development of novel targeted therapeutic approaches in a dynamic manner.

Role of Non-Coding RNA of Human Platelet in Cardiovascular Disease

Cardiovascular diseases (CVD) are the major cause of death in the world. Numerous genetic studies involving transcriptomic approaches aimed at the detailed understanding of the disease and the development of new therapeutic strategies have been conducted over recent years. There has been an increase in research on platelets, which are implicated in CVD due to their capacity to release regulatory molecules that affect various pathways. Platelets secrete over 500 various kinds of molecules to plasma including large amounts of non-coding (nc) RNA (miRNA, lncRNA or circRNA). These ncRNA correspond to 98% of transcripts that are not translated into proteins as they are important regulators in physiology and disease. Thus, miRNAs can direct protein complexes to mRNAs through base-pairing interactions, thus causing translation blockage or/and transcript degradation. The lncRNAs act via different mechanisms by binding to transcription factors. Finally, circRNAs act as regulators of miRNAs, interfering with their action. Alteration in the repertoire and/or the amount of the platelet-secreted ncRNA can trigger CVD as well as other diseases. NcRNAs can serve as effective biomarkers for the disease or as therapeutic targets due to their disease involvement. In this review, we will focus on the most important ncRNAs that are secreted by platelets (9 miRNA, 9 lncRNA and 5 circRNA), their association with CVD, and the contribution of these ncRNA to CVD risk to better understand the relation between ncRNA of human platelet and CVD.

Maternally expressed gene 3 regulates retinal neovascularization in retinopathy of prematurity

The mouse model of oxygen induced retinopathy is suitable for the study of various retinal neovascularization diseases, including retinopathy of prematurity. The maternally expressed gene 3 (MEG3) has been demonstrated to have an inhibitory effect on diabetic retinopathy. In this study, we investigated the role of MEG3 overexpression in oxygen-induced retinopathy in mice. The results showed that MEG3 overexpression effectively inhibited the production of retinal neovascularization in oxygen-induced retinopathy mice. It acts by down-regulating the expression of phosphoinositide 3-kinase, serine/threonine kinase, and vascular endothelial growth factor and pro-inflammatory factors. MEG3 overexpression lentivirus has a future as a new method for the clinical treatment of retinopathy of prematurity. The animal experiments were approved by the Animal Ethics Committee of Shengjing Hospital of China Medical University, China (approval No. 2016PS074K) on February 25, 2016.

PDCD4 Simultaneously Promotes Microglia Activation via PDCD4-MAPK-NF-κB Positive Loop and Facilitates Neuron Apoptosis During Neuroinflammation

Neuroinflammation and neuron injury are common features of the central nervous system (CNS) diseases. It is of great significance to identify their shared key regulatory molecules and thus explore the potential therapeutic targets. Programmed cell death factor 4 (PDCD4), an apoptosis-related molecule, extensively participates in tumorigenesis and inflammatory diseases, but its expression and biological function during CNS neuroinflammation remain unclear. In the present study, utilizing the lipopolysaccharide (LPS)-induced neuroinflammation model in mice, we reported an elevated expression of PDCD4 both in injured neurons and activated microglia of the inflamed brain. A similar change in PDCD4 expression was observed in vitro in the microglial activation model. Silencing PDCD4 by shRNA significantly inhibited the phosphorylation of MAPKs (p38, ERK, and JNK), prevented the phosphorylation and nuclear translocation of NF-κB p65, and thus attenuated the LPS-induced microglial inflammatory activation. Interestingly, LPS also required the MAPK/NF-κB signaling activation to boost PDCD4 expression in microglia, indicating the presence of a positive loop. Moreover, a persistent elevation of PDCD4 expression was detected in the H₂O₂-induced neuronal oxidative damage model. Knocking down PDCD4 significantly inhibited the expression of pro-apoptotic proteins BAX and Cleaved-PARP, suggesting the proapoptotic activity of PDCD4 in neurons. Taken together, our data indicated that PDCD4 may serve as a hub regulatory molecule that simultaneously promotes the microglial inflammatory activation and the oxidative stress-induced neuronal apoptosis within CNS. The microglial PDCD4-MAPK-NF-κB positive feedback loop may act as pivotal signaling for neuroinflammation which subsequently exaggerates neuronal injury, and thus may become a potential therapeutic target for neuroinflammatory diseases.

LncRNA RP11-400K9.4 Aggravates Cardiomyocytes Apoptosis After Hypoxia/Reperfusion Injury by Targeting miR-423

Our study was aimed at exploring the roles of lncRNA RP11-400K9.4 (RP11-400K9.4) on hypoxia/reoxygenation (H/R) -induced cardiomyocytes apoptosis. H/R model was constructed in rat primary cardiomyocytes (PC) and H9c2 cells. In this study, the results showed that H/R significantly induced the apoptosis of PC and H9c2 cells. The expression of RP11-400K9.4 was upregulated in H/R-induced PC and H9c2 cells, but miR-423 expression was downregulated. Silencing RP11-400K9.4 could attenuate H/R-induced apoptosis in PC and H9c2 cells. We also found that miR-423 was a potential target of RP11-400K9.4. The effect of silencing RP11-400K9.4 on H/R-induced apoptosis of PC and H9c2 cells was significantly reversed by miR-423 inhibitor transfection. Furthermore, our data confirmed that silencing RP11-400K9.4 promoted the activation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) /extracellular signal-regulated kinase (ERK) pathways and these phenomena can be reversed by miR-423 inhibitor transfection. In conclusion, our study demonstrated that silencing RP11-400K9.4 could alleviate H/R-induced cardiomyocytes damages via suppressing apoptosis by targeting miR-423 with the activation of PI3K/AKT and MEK/ERK signaling pathways.

Receptor tyrosine kinase ROR1 ameliorates Aβ1-42 induced cytoskeletal instability and is regulated by the miR146a-NEAT1 nexus in Alzheimer's disease

Alzheimer’s disease (AD) involves severe cytoskeletal degradation and microtubule disruption. Here, we studied the altered dynamics of ROR1, a Receptor Tyrosine Kinase (RTK), and how it could counter these abnormalities. We found that in an Aβ_1–42 treated cell model of AD, ROR1 was significantly decreased. Over expressed ROR1 led to the abrogation of cytoskeletal protein degradation, even in the presence of Aβ_1–42, preserved the actin network, altered actin dynamics and promoted neuritogenesis. Bioinformatically predicted miRNAs hsa-miR-146a and 34a were strongly up regulated in the cell model and their over expression repressed ROR1. LncRNA NEAT1, an interactor of these miRNAs, was elevated in mice AD brain and cell model concordantly. RNA Immunoprecipitation confirmed a physical interaction between the miRNAs and NEAT1. Intuitively, a transient knock down of NEAT1 increased their levels. To our knowledge, this is the first instance which implicates ROR1 in AD and proposes its role in preserving the cytoskeleton. The signalling modalities are uniquely analyzed from the regulatory perspectives with miR-146a and miR-34a repressing ROR1 and in turn getting regulated by NEAT1.

RNA Methylations in Cardiovascular Diseases, Molecular Structure, Biological Functions and Regulatory Roles in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in the world. Despite considerable progress in the diagnosis, treatment and prognosis of CVDs, new diagnostic biomarkers and new therapeutic measures are urgently needed to reduce the mortality of CVDs and improve the therapeutic effect. RNA methylations regulate almost all aspects of RNA processing, such as RNA nuclear export, translation, splicing and non-coding RNA processing. In view of the importance of RNA methylations in the pathogenesis of diseases, this work reviews the molecular structures, biological functions of five kinds of RNA methylations (m6A, m5C, m1a, m6am and m7G) and their effects on CVDs, including pulmonary hypertension, hypertension, vascular calcification, cardiac hypertrophy, heart failure. In CVDs, m6A “writers” catalyze the installation of m6A on RNAs, while “erasers” remove these modifications. Finally, the “readers” of m6A further influence the mRNA splicing, nuclear export, translation and degradation. M5C, m1A, m6Am and m7G are new types of RNA methylations, their roles in CVDs need to be further explored. RNA methylations have become a new research hotspot and the roles in CVDs is gradually emerging, the review of the molecular characteristics, biological functions and effects of RNA methylation on CVDs will contribute to the elucidation of the pathological mechanisms of CVDs and the discovery of new diagnostic markers and therapeutic targets of CVDs.

miR-200a-3p Attenuates Coronary Microembolization-Induced Myocardial Injury in Rats by Inhibiting TXNIP/NLRP3-Mediated Cardiomyocyte Pyroptosis

Coronary microembolization (CME) commonly develops as a complication after percutaneous coronary intervention (PCI), and associated inflammation is a leading driver of myocardial damage. Cardiomyocyte loss in the context of ischemic myocardial disease has been linked to inflammatory pyroptotic cell death. Additionally, miR-200a-3p dysregulation has been linked to myocardial ischemia-reperfusion and many other pathological conditions. However, how miR-200a-3p impacts cardiomyocyte pyroptosis in the context of CME remains to be assessed. Herein, a rat model of CME was established via the injection of microembolic spheres into the left ventricle. When myocardial tissue samples from these rats were analyzed, miR-200a-3p levels were markedly decreased, whereas thioredoxin-interacting protein (TXNIP) levels were increased. The ability of miR-200a-3p to directly target TXNIP and to control its expression was confirmed via dual-luciferase reporter assay. Adeno-associated virus serotype 9-pre-miR-200a-3p (AAV-miR-200a-3p) construct transfection was then employed as a means of upregulating this miRNA in CME model rats. Subsequent assays, including echocardiography, enzyme-linked immunosorbent assays (ELISAs), hematoxylin-eosin (H&E) staining, hematoxylin-basic fuchsin-picric acid (HBFP) staining, TdT-mediated dUTP nick-end labeling (TUNEL) staining, immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting revealed that miR-200a-3p overexpression inhibited cardiomyocyte pyroptosis and alleviated CME-induced myocardial injury by inhibiting the TXNIP/NOD-like receptor family pyrin domain-containing 3 (NLRP3) pathway. The ability of miR-200a-3p to protect against CME-induced myocardial injury thus highlights a novel approach to preventing or treating such myocardial damage in clinical settings.

LncRNAs as Therapeutic Targets and Potential Biomarkers for Lipid-Related Diseases

Lipid metabolism is an essential biological process involved in nutrient adjustment, hormone regulation, and lipid homeostasis. An irregular lifestyle and long-term nutrient overload can cause lipid-related diseases, including atherosclerosis, myocardial infarction (MI), obesity, and fatty liver diseases. Thus, novel tools for efficient diagnosis and treatment of dysfunctional lipid metabolism are urgently required. Furthermore, it is known that lncRNAs based regulation like sponging microRNAs (miRNAs) or serving as a reservoir for microRNAs play an essential role in the progression of lipid-related diseases. Accordingly, a better understanding of the regulatory roles of lncRNAs in lipid-related diseases would provide the basis for identifying potential biomarkers and therapeutic targets for lipid-related diseases. This review highlighted the latest advances on the potential biomarkers of lncRNAs in lipid-related diseases and summarised current knowledge on dysregulated lncRNAs and their potential molecular mechanisms. We have also provided novel insights into the underlying mechanisms of lncRNAs which might serve as potential biomarkers and therapeutic targets for lipid-related diseases. The information presented here may be useful for designing future studies and advancing investigations of lncRNAs as biomarkers for diagnosis, prognosis, and therapy of lipid-related diseases.

Role of long non-coding RNAs in adipogenesis: State of the art and implications in obesity and obesity-associated diseases

Obesity is an evolutionary, chronic, and relapsing disease that consists of a pathological accumulation of adipose tissue able to increase morbidity for high blood pressure, type 2 diabetes, metabolic syndrome, and obstructive sleep apnea in adults, children, and adolescents. Despite intense research over the last 20 years, obesity remains today a disease with a complex and multifactorial etiology. Recently, long non-coding RNAs (lncRNAs) are emerging as interesting new regulators as different lncRNAs have been found to play a role in early and late phases of adipogenesis and to be implicated in obesity-associated complications onset. In this review, we discuss the most recent advances on the role of lncRNAs in adipocyte biology and in obesity-associated complications. Indeed, more and more researchers are focusing on investigating the underlying roles that these molecular modulators could play. Even if a significant number of evidence is correlation-based, with lncRNAs being differentially expressed in a specific disease, recent works are now focused on deeply analyzing how lncRNAs can effectively modulate the disease pathogenesis onset and progression. LncRNAs possibly represent new molecular markers useful in the future for both the early diagnosis and a prompt clinical management of patients with obesity.

Circular RNA PVT1 silencing prevents ischemia-reperfusion injury in rat by targeting microRNA-125b and microRNA-200a

Circular RNAs (circRNAs) are essential regulators associated with many cardiac conditions, including myocardial infarction (MI). This study aimed to explore circRNA expression during MI development in an animal model and in hypoxia/reoxygenation (H/R)-treated cardiomyocytes. Microarray and real-time quantitative PCR showed that the circRNA PVT1 (circPVT1) was expressed at high levels in MI tissues and H/R-triggered cardiomyocytes. Loss-of-function assays were utilized for examining the influence of circPVT1 on cardiac function and cardiomyocyte properties. Cardiac function was measured by echocardiography at 7 d after MI. Reduced circPVT1 expression significantly decreased MI-triggered myocardial infarct size by 60% and prevented MI-triggered reductions in fractional shortening (%FS) and ejection fraction (EF%). Results of LDH, CCK-8, EdU staining, colony formation assays, and flow cytometry showed that circPVT1 silencing restored cell viability and proliferation while decreased apoptosis. Mechanistic experiments indicated that microRNAs (miR)-125b and miR-200a associated with circPVT1. We demonstrated that circPVT1 functioned as a competitive endogenous RNA (ceRNA) to sponge both miR-125b and miR-200a. Gain-of-function assays showed that miR-125b and miR-200a upregulation partially eliminated the effects of circPVT1 on cardiomyocyte properties. In addition, we found that the previously reported p53/TRAF6, SIRT7, Keap1/Nrf2, and PDCD4 pathways were regulated by the circPVT1/miR-125b/miR-200a axis. In conclusion, our study suggests that circPVT1 protects the myocardium from MI and H/R injury by preventing miR-125b- and miR-200a-mediated apoptotic signaling.

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.

mRNA modifications in cardiovascular biology and disease: with a focus on m6A modification

Among several known RNA modifications, N6-methyladenosine (m6A) is the most studied RNA epitranscriptomic modification and controls multiple cellular functions during development, differentiation, and disease. Current research advancements have made it possible to examine the regulatory mechanisms associated with RNA methylation and reveal its functional consequences in the pathobiology of many diseases, including heart failure. m6A methylation has been described both on coding (mRNA) and non-coding RNA species including rRNA, tRNA, small nuclear RNA and circular RNAs. The protein components which catalyze the m6A methylation are termed methyltransferase or "m6A writers." The family of proteins that recognize this methylation are termed "m6A readers" and finally the enzymes involved in the removal of a methyl group from RNA are known as demethylases or "m6A erasers." At the cellular level, different components of methylation machinery are tightly regulated by many factors to maintain the m6A methylation dynamics. The m6A methylation process impacts different stages of mRNA metabolism and the biogenesis of long non-coding RNA and miRNA. Although, mRNA methylation was initially described in the 1970s, its regulatory roles in various diseases, including cardiovascular diseases are broadly unexplored. Recent investigations suggest the important role of m6A mRNA methylation in both hypertrophic and ischemic heart diseases. In the present review, we evaluate the significance of m6A methylation in the cardiovascular system, in cardiac homeostasis and disease, all of which may help to improve therapeutic intervention for the treatment of heart failure.

Long Noncoding RNAs in Myocardial Ischemia-Reperfusion Injury

Following an acute myocardial infarction, reperfusion therapy is currently the most effective way to save the ischemic myocardium; however, restoring blood flow may lead to a myocardial ischemia-reperfusion injury (MIRI). Recent studies have confirmed that long-chain noncoding RNAs (LncRNAs) play important roles in the pathophysiology of MIRIs. These LncRNA-mediated roles include cardiomyocyte apoptosis, autophagy, necrosis, oxidative stress, inflammation, mitochondrial dysfunction, and calcium overload, which are regulated through the expression of target genes. Thus, LncRNAs may be used as clinical diagnostic markers and therapeutic targets to treat or prevent MIRI. This review evaluates the research on LncRNAs involved in MIRIs and provides new ideas for preventing and treating this type of injury.

MiR-200a-3p Aggravates DOX-Induced Cardiotoxicity by Targeting PEG3 Through SIRT1/NF-κB Signal Pathway

Doxorubicin (DOX) is a widely used cytotoxic drug whose application is limited by its severe side effects. Little was known regarding how to offset its side effects. Therefore this study aims to explore the role of miR-200a-3p in DOX-induced cardiotoxicity and its possible mechanism. DOX-induced myocardial injury rat models were established, which were then injected with miR-200a-3p inhibitor (miR-200a-3p suppression) to observe the effects of miR-200a-3p on cell proliferation, and apoptosis. Heart function and weights of rat models were also measured. Cardiomyocytes were induced by DOX, in which PEG3 knockdown or corresponding plasmids were transfected to assess the possible effect of PEG3 on cell activity. Dual luciferase reporter assay was applied to verify the binding of PEG3 with miR-200a-3p. Elevated levels of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) and left ventricular end-diastolic pressure (LVEDP), as well as suppressed left ventricular systolic pressure (LVSP) and ± dp/dt max were showed in myocardial injury rat models. DOX induced myocardial injury and increased miR-200a-3p expression levels. miR-200a-3p inhibitor could partially attenuate DOX-induced cardiotoxicity in rat models, while PEG3 could regulate myocardial injury in DOX-treated cell models. miR-200a-3p, by targeting PEG3 through SIRT1/NF-κB signal pathway, regulated cell proliferation, inflammation and apoptosis of myocardiocytes. The results in current study demonstrated that miR-200a-3p regulates cell proliferation and apoptosis of cardiomyocytes by targeting PEG3 through SIRT1/NF-κB signal pathway. This result may provide a potential clue for the treatment of DOX-induced cardiotoxicity.

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.

Cell type-specific microRNA therapies for myocardial infarction

Current interventions fail to recover injured myocardium after infarction and prompt the need for development of cardioprotective strategies. Of increasing interest is the therapeutic use of microRNAs to control gene expression through specific targeting of mRNAs. In this Review, we discuss current microRNA-based therapeutic strategies, describing the outcomes and limitations of key microRNAs with a focus on target cell types and molecular pathways. Last, we offer a perspective on the outlook of microRNA therapies for myocardial infarction, highlighting the outstanding challenges and emerging strategies.

Long Noncoding RNA/Circular RNA-miRNA-mRNA Axes in Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) elicits tissue injury involved in a wide range of pathologies. Multiple studies have demonstrated that noncoding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), participate in the pathological development of IRI, and they may act as biomarkers, therapeutic targets, or prognostic indicators. Nonetheless, the specific molecular mechanisms of ncRNAs in IRI have not been completely elucidated. Regulatory networks among lncRNAs/circRNAs, miRNAs, and mRNAs have been the focus of attention in recent years. Studies on the underlying molecular mechanisms have contributed to the discovery of therapeutic targets or strategies in IRI. In this review, we comprehensively summarize the current research on the lncRNA/circRNA-miRNA-mRNA axes and highlight the important role of these axes in IRI.

Programmed cell death factor 4 (PDCD4), a novel therapy target for metabolic diseases besides cancer

Programmed cell death factor 4 (PDCD4) is originally described as a tumor suppressor gene that exerts antineoplastic effects by promoting apoptosis and inhibiting tumor cell proliferation, invasion, and metastasis. Several investigations have probed the aberrant expression of PDCD4 with the progression of metabolic diseases, such as polycystic ovary syndrome (PCOS), obesity, diabetes, and atherosclerosis. It has been ascertained that PDCD4 causes glucose and lipid metabolism disorders, insulin resistance, oxidative stress, chronic inflammatory response, and gut flora disorders to regulate the progression of metabolic diseases. This review aims to summarize the latest researches to uncover the structure, expression regulation, and biological functions of PDCD4 and to elucidate the regulatory mechanism of the development of tumors and metabolic diseases. This review has emphasized the understanding of the PDCD4 role and to provide new ideas for the research, diagnosis, and treatment of tumors and metabolic diseases.

Long non-coding RNA plasmacytoma variant translocation 1 linked to hypoxia-induced cardiomyocyte injury of H9c2 cells by targeting miR-135a-5p/forkhead box O1 axis

Background

Myocardial infarction occurs due to insufficient (ischemia) blood supply to heart for long time; plasmacytoma variant translocation 1 (PVT1) is a long non-coding RNAs (lncRNAs) involved in the pathogenesis of various diseases, including heart disease; However, few studies have explored its role. The present study evaluated the effects of lncRNA PVT1 on hypoxic rat H9c2 cells.

Methods

Hypoxic injury was examined by measuring cell viability and apoptosis by using cell counting kit-8 activity and flow cytometry assays. Gene expressions after hypoxia were estimated by quantitative real time polymerase chain reaction and the signaling pathway were explored by Western blot analysis. RNA immunoprecipitation and luciferase reporter assays were applied to examine the interactions among genes. Data were analyzed using t-test with one-way or two-way analysis of variance.

Results

The lncRNA PVT1 is up-regulated in hypoxia-stressed H9c2 cells and knockdown of PVT1 mitigates hypoxia-induced injury in H9c2 cells. PVT1 acts as a sponge for miR-135a-5p and knockdown of PVT1 attenuated the increased hypoxia-induced injury by up-regulating miR-135a-5p. Forkhead box O1 (FOXO1) was identified as a target of miR-135a-5p, and the expression was negatively regulated by miR-135a-5p. The exploration of the underlying mechanism demonstrated that knockdown of FOXO1 reversed PVT1/miR-135a-5p mediated hypoxia-induced injury in H9c2 cells.

Conclusions

PVT1 plays a crucial role in hypoxia-injured H9c2 cells through sponging miR-135a-5p and then positively regulating FOXO1.

The roles of long noncoding RNAs in myocardial pathophysiology

Long noncoding RNAs (lncRNAs), more than 200 nt in length, are functional molecules found in various species. These lncRNAs play a vital role in cell proliferation, differentiation, and degeneration and are also involved in pathophysiological processes of cancer and neurodegenerative, autoimmune, and cardiovascular diseases (CVDs). In recent years, emerging challenges for intervention studies on ischemic heart diseases have received much attention. LncRNAs have a key function in the alleviation of myocardial infarction (MI) injury and myocardial ischemia–reperfusion injury. During cardiac hypertrophy (CH) and fibrosis, cardiac cells undergo structural changes and become dysfunctional due to the effects of neurohormonal factors. LncRNAs may serve as important therapeutic targets that promote cardiac remodeling and then retard the development of heart failure (HF). In addition, studies on the roles and mechanisms of action of lncRNAs participating in cardiac pathophysiology via other factors have become the focus of research worldwide. Here, we review the current knowledge on various lncRNAs and their functions in cardiac biology, particularly concentrating on ischemic heart disease, CH, and cardiac fibrosis. We next discuss the predictive value of lncRNAs as diagnostic biomarkers of CVDs.

Functional characterization of long noncoding RNAs

PURPOSE OF REVIEW

Mounting evidence suggests that long noncoding RNAs (lncRNAs) are essential regulators of gene expression. Although few lncRNAs have been the subject of detailed molecular and functional characterization, it is believed that lncRNAs play an important role in tissue homeostasis and development. In fact, gene expression profiling studies reveal lncRNAs are developmentally regulated in a tissue-type and cell-type specific manner. Such findings have brought significant attention to their potential contribution to disease cause. The current review summarizes recent studies of lncRNAs in the heart.

RECENT FINDINGS

lncRNA discovery has largely been driven by the implementation of next generation sequencing technologies. To date, such technologies have contributed to the identification of tens of thousands of distinct lncRNAs in humans -- accounting for a large majority of all RNA sequences transcribed across the human genome. Although the functions of these lncRNAs remain largely unknown, gain-of-function and loss-of-function studies (in vivo and in vitro) have uncovered a number of mechanisms by which lncRNAs regulate gene expression and protein function. Such mechanisms have been stratified according to three major functional categories: RNA sponges (RNA-mediated sequestration of free miRNAs; e.g. H19, MEG3, and MALAT1); transcription-modulating lncRNAs (RNA influences regulatory factor recruitment by binding to histone modifiers or transcription factors; e.g. CAIF, MANTIS, and NEAT1); and translation-modulating lncRNAs (RNA modifies protein function via directly interacting with a protein itself or binding partners; e.g. Airn, CCRR, and ZFAS1).

SUMMARY

Recent studies strongly suggest that lncRNAs function via binding to macromolecules (e.g. genomic DNA, miRNAs, or proteins). Thus, lncRNAs constitute an additional mode by which cells regulate gene expression.

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.

Carboplatin Inhibits the Progression of Retinoblastoma Through IncRNA XIST/miR-200a-3p/NRP1 Axis

Objective

This study was set out to explore the expression and related mechanism of XIST and miR-200a-3p in retinoblastoma (Rb).

Patients and Methods

Fifty-four children with Rb who came to our hospital for surgery from January 2018 to September 2019 were collected. In addition, Rb cells and human retinal epithelial cells were purchased. XIST-siRNA (si-XIST), XIST-shRNA (sh-XIST), empty vector plasmid (siRNA-NC), miR-200a-3p-mimics and miR −200a-3p-inhibition were transfected into Y79 cells. The expression of XIST and miR-200a-3p in the samples were determined by qRT-PCR. β-catenin, cyclin B1, cyclin D1, Bax, Caspase-3, N-cadherin, vimentin, Snail, E-Cadherin and ZO-1 protein levels were measured by WB. MTT, Transwell and flow cytometry were utilized to detect cell proliferation, invasion, and apoptosis, respectively.

Results

XIST was highly expressed while miR-200a-3p was lowly expressed in patients’ tissues, and the AUC of both was over 0.8. XIST and miR-200a-3p was related to differentiation degree in Rb patients. Y79 cells were selected for transfection. Compared with the siRNA-NC group, XIST was significantly reduced in the siRNA-XIST group, and it was significantly increased in the shRNA-XIST group (P<0.01). The proliferation capacity of siRNA-XIST group was decreased, while that of shRNA-XIST group was up-regulated. The apoptosis rate of siRNA-XIST group was significantly up-regulated, while that of shRNA-XIST group was decreased (P<0.001). The invasive capacity of siRNA-XIST group was decreased, while that of shRNA-XIST group was up-regulated (P<0.001). Silencing XIST and over-expressed miR-200a-3p could inhibit cell epithelial–mesenchymal transition (EMT), proliferation, invasion, and promote apoptosis. WB detection showed that Carboplatin + LncRNA XIST intervention group could more significantly inhibit β-catenin, cyclin B1, cyclin D1, N-cadherin, vimentin, Snail protein, and promote the up-regulation of Bax, Caspase-3, E-Cadherin and ZO-1 expression.

Conclusion

Inhibition of XIST expression can up-regulate miR-200a-3p-mediated PI3K-Akt/MAPK-ERK signaling pathway and affect cell EMT, proliferation, invasion, and apoptosis, which is expected to be a potential therapeutic target for Rb.

Long non-coding RNA SAP30-2:1 is downregulated in congenital heart disease and regulates cell proliferation by targeting HAND2

Congenital heart disease (CHD) is the most common birth defect worldwide. Long non-coding RNAs (lncRNAs) have been implicated in many diseases. However, their involvement in CHD is not well understood. This study aimed to investigate the role of dysregulated lncRNAs in CHD. We used Gene Expression Omnibus data mining, bioinformatics analysis, and analysis of clinical tissue samples and observed that the novel lncRNA SAP30-2:1 with unknown function was significantly downregulated in damaged cardiac tissues from patients with CHD. Knockdown of lncRNA SAP30-2:1 inhibited the proliferation of human embryonic kidney and AC16 cells and decreased the expression of heart and neural crest derivatives expressed 2 (HAND2). Moreover, lncRNA SAP30-2:1 was associated with HAND2 by RNA immunoprecipitation. Overall, these results suggest that lncRNA SAP30-2:1 may be involved in heart development through affecting cell proliferation via targeting HAND2 and may thus represent a novel therapeutic target for CHD.

Identification of mitochondrial function-associated lncRNAs in septic mice myocardium

The present study aimed to analyze long noncoding RNA (lncRNA) and messenger RNA (mRNA) expression profiles in septic mice heart and to identify potential lncRNAs and mRNAs that be responsible for cardiac mitochondrial dysfunction during sepsis. Mice were treated with 10 mg/kg of lipopolysaccharides to induce sepsis. LncRNAs and mRNAs expression were evaluated by using lncRNA and mRNA microarray or real-time polymerase chain reaction technique. LncRNA-mRNA coexpression network assay, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed. The results showed that 1275 lncRNAs were differentially expressed in septic myocardium compared with those in the control group. A total of 2769 mRNAs were dysregulated in septic mice heart, most of which are mainly related to the process of inflammation, mitochondrial metabolism, oxidative stress, and apoptosis. Coexpression network analysis showed that 14 lncRNAs were highly correlated with 11 mitochondria-related differentially expressed mRNA. Among all lncRNAs and their cis-acting mRNAs, 41 lncRNAs-mRNA pairs (such as NONMMUG004378 and Apaf1 gene) were enriched in GO terms and KEGG pathways. In summary, we gained some specific lncRNAs and their potential target mRNAs that might be involved in mitochondrial dysfunction in septic myocardium. These findings provide a panoramic view of lncRNA and might allow developing new treatment strategies for sepsis.

The role of molecular mechanism of Ten-Eleven Translocation2 (TET2) family proteins in pathogenesis of cardiovascular diseases (CVDs)

Cardiovascular disease (CVD) is one of the most common diseases worldwide. The underlying pathogenesis of the disease has not yet been determined, but many factors have been identified. Tet methylcytosine dioxygenase 2 (TET2) is one of the epigenetic factors involved in regulating many genes. Therefore, based on the studies shown, this factor plays an important role in preventing the occurrence of CVD. TET2 has been shown to increase angiogenesis by expressing Robo4. It also increases the activity of Matrix metalloproteinases (MMPs) and stimulates the secretion of Vascular endothelial growth factor angiogenesis. On the other hand, it has been shown that TET2 regulates the expression of several genes and the development of the heart during the embryonic period due to its oxygenating role. TET2 has been shown to regulates the expression of the genes such as Ying Yang1 (YY1), Sox9b, Inhbaa and many other genes that ultimately lead to the differentiation of cardiomyocytes. On the other hand, it has been shown that some Long non coding RNA and MicroRNAs reduce TET2 expression and CVD. Finally, it is concluded that inducing TET2 expression can be a good therapeutic strategy to prevent or improve CVD.

Non-coding RNAs participate in the ischemia-reperfusion injury

Ischemia, being defined as blood supply deficiency is involved in the pathogenesis of a number of life-threatening conditions such as myocardial infarction and cerebral stroke. Assessment of the molecular pathology of these conditions has led to identification of the role of reperfusion in induction and aggravation of tissue injury and necrosis. Thus, the term "ischemia/ reperfusion (I/R) injury" has been introduced. This process involves aberrant regulation of the mitochondrial function, apoptotic and autophagic pathways and signal transducers. More recently, non-coding RNAs including long non-coding RNAs (lncRNAs) ad microRNAs (miRNAs) have been shown to influence I/R injury. Animal studies and clinical investigations have shown up-/down-regulation of tens of lncRNAs and miRNAs in this process. In the current study, we summarize the role of these transcripts in the pathophysiology of I/R injury and their potential as biomarkers for detection of extent of tissue injury.

Hypermethylation-mediated down-regulation of lncRNA TBX5-AS1:2 in Tetralogy of Fallot inhibits cell proliferation by reducing TBX5 expression

Tetralogy of Fallot (TOF) is the most common complex congenital heart disease (CHD) with uncertain cause. Although long non‐coding RNAs (lncRNAs) have been implicated in heart development and several CHDs, their role in TOF is not well understood. This study aimed to investigate how dysregulated lncRNAs contribute to TOF. Using Gene Expression Omnibus data mining, bioinformatics analysis and clinical heart tissue sample detecting, we identified a novel antisense lncRNA TBX5‐AS1:2 with unknown function that was significantly down‐regulated in injured cardiac tissues from TOF patients. LncRNA TBX5‐AS1:2 was mainly located in the nucleus of the human embryonic kidney 293 (HEK293T) cells and formed an RNA‐RNA double‐stranded structure in the overlapping region with its sense mRNA T‐box transcription factor 5 (TBX5), which is an important regulator in heart development. Knock‐down of lncRNA TBX5‐AS1:2 via promoter hypermethylation reduced TBX5 expression at both the mRNA and protein levels by affecting its mRNA stability through RNA‐RNA interaction. Moreover, lncRNA TBX5‐AS1:2 knock‐down inhibited the proliferation of HEK293T cells. In conclusion, these results indicated that lncRNA TBX5‐AS1:2 may be involved in TOF by affecting cell proliferation by targeting TBX5.

Novel Mechanisms of Exercise-Induced Cardioprotective Factors in Myocardial Infarction

Exercise training has been reported to ameliorate heart dysfunction in both humans and animals after myocardial infarction (MI). Exercise-induced cardioprotective factors have been implicated in mediating cardiac repair under pathological conditions. These protective factors secreted by or enriched in the heart could exert cardioprotective functions in an autocrine or paracrine manner. Extracellular vesicles, especially exosomes, contain key molecules and play an essential role in cell-to-cell communication via delivery of various factors, which may be a novel target to study the mechanism of exercise-induced benefits, besides traditional signaling pathways. This review is designed to demonstrate the function and underlying protective mechanism of exercise-induced cardioprotective factors in MI, with an aim to offer more potential therapeutic targets for MI.

Long non‑coding RNA GAS5 regulates myocardial ischemia‑reperfusion injury through the PI3K/AKT apoptosis pathway by sponging miR‑532‑5p

Long non‑coding RNAs (lncRNAs) have been revealed to have a marked effect in cardiovascular diseases, including during cardiac development, cardiac hypertrophy, myocardial fibrosis and myocardial ischemic injury. The mechanism of myocardial ischemia‑reperfusion injury (MIRI) is very complicated. Although studies have confirmed that lncRNAs are involved, the specific mechanism remains largely unknown. The lncRNA growth arrest specific 5 (GAS5) is known as a regulator of a number of diseases, including certain cancer types. The present study aimed to investigate the function of lncRNA GAS5 in MIRI. The present study reported that the expression of lncRNA GAS5 in H9c2 cells treated with anoxia and reoxygenation was significantly upregulated compared with the control group (P<0.05). Similarly, the expression of lncRNA GAS5 in myocardial tissue obtained from rats treated with MIRI was significantly upregulated compared with the untreated controls (P<0.05). Silencing of lncRNA GAS5 was able to attenuate myocardial damage, as cell viability increased and the apoptosis rate decreased. Classical apoptotic proteins involved in MIRI, including B‑cell lymphoma 2, Bcl‑2‑associated X protein and cleaved caspase‑3, also exhibited the same trend. At the same time, when lncRNA GAS5 was silenced, microRNA (miR)‑532‑5p, which was originally expressed at the stage of injury, was upregulated. The luciferase reporter assay results indicated that the lncRNA GAS5 functioned as a molecular sponge of miR‑532‑5p. The gain‑ and loss‑of‑function analysis of miR‑532‑5p indicated that it was involved in the regulation of MIRI; the trend of results following its overexpression was also consistent with the trend observed following the silencing of lncRNA GAS5. Notably, the protective effect of lncRNA GAS5 silencing on cells was attenuated by miR‑532‑5p inhibition. Phosphatase and tensin homolog was revealed to be a key target gene for the function of lncRNA GAS5, and its regulation was achieved via binding to miR‑532‑5p. In other words, silencing lncRNA GAS5 ultimately promoted the activation of the phosphoinositide‑3‑kinase (PI3K)/protein kinase B pathway (AKT) to reduce myocardial damage. Therefore, lncRNA GAS5 was able to regulate MIRI through the PI3K/AKT apoptosis pathway by sponging miR‑532‑5p.

Molecular therapies delaying cardiovascular aging: disease- or health-oriented approaches

Regenerative medicine is a new therapeutic modality that aims to mend tissue damage by encouraging the reconstitution of physiological integrity. It represents an advancement over conventional therapies that allow reducing the damage but result in disease chronicization. Age-related decline in spontaneous capacity of repair, especially in organs like the heart that have very limited proliferative capacity, contributes in reducing the benefit of conventional therapy. ncRNAs are emerging as key epigenetic regulators of cardiovascular regeneration. Inhibition or replacement of miRNAs may offer reparative solutions to cardiovascular disease. The first part of this review article is devoted to illustrating novel therapies emerging from research on miRNAs. In the second part, we develop new therapeutic concepts emerging from genetics of longevity. Prolonged survival, as in supercentenarians, denotes an exceptional capacity to repair and cope with risk factors and diseases. These characteristics are shared with offspring, suggesting that the regenerative phenotype is heritable. New evidence indicates that genetic traits responsible for prolongation of health span in humans can be passed to and benefit the outcomes of animal models of cardiovascular disease. Genetic studies have also focused on determinants of accelerated senescence and related druggable targets. Evolutionary genetics assessing the genetic basis of adaptation and comparing successful and unsuccessful genetic changes in response to selection within populations represent a powerful basis to develop novel therapies aiming to prolong cardiovascular and whole organism health.

MALAT1 affects hypoxia-induced vascular endothelial cell injury and autophagy by regulating miR-19b-3p/HIF-1α axis

Cardiovascular disease has become the leading cause of death in the world. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays an important role in cardiovascular disease, such as stroke. However, the role of MALAT1 in hypoxia (HYP)-induced vascular endothelial cells (VECs) remains unclear. In the present study, HYP-treated human umbilical vein endothelial cells (HUVECs) were utilized to simulate HYP-induced VEC injury. It was found that after HYP treatment, the levels of MALAT1 and hypoxia-induced factor-1 (HIF-1α) in HUVECs were upregulated, while the level of miR-19b-3p was downregulated. Knockdown of MALAT1 with siRNA significantly reduced the HIF-1α level induced by HYP. In addition, MALAT1 knockdown inhibited HYP-induced HUVECs apoptosis, autophagy and inflammation. The overexpression of HIF-1α overcame the effect of MALAT1 knockdown. Mechanism analysis showed that MALAT1-targeted miR-19b-3p and then regulated downstream HIF-1α. MALAT1 knockdown increased the level of miR-19b-3p in cells, and increased miR-19b-3p further inhibited the expression of HIF-1α, thereby reducing the HYP-induced HUVECs apoptosis, autophagy and inflammation. Taken together, these results suggest that MALAT1 may be a potential target for mitigating HYP-induced endothelial cell injury.