The lncRNA, H19 Mediates the Protective Effect of Hypoxia Postconditioning Against Hypoxia-Reoxygenation Injury to Senescent Cardiomyocytes by Targeting microRNA-29b-3p

Isoflurane pretreatment protects against myocardial ischemia/reperfusion injury via mediating lncRNA CASC15/miR-542-3p axis

The protective effect of isoflurane on cardiomyocyte ischemia/reperfusion injury (I/RI) was explored in hypoxia and reoxygenation (H/R) induced cardiomyocyte injury model. In terms of mechanism, the participation of long non-coding RNA CASC15/microR-542-3p axis was further discussed. H9c2 cells received H/R treatment to mimic myocardial I/RI. RT-qPCR was performed to quantify mRNA levels. Cell viability and apoptosis were evaluated after isoflurane pretreatment and cell transfection. ELISA was performed to measure the concentrations of inflammatory/oxidative stress-related cytokines (TNF-α, IL-6, MDA, SOD). The target relationship between CASC12 and miR-542-3p was determined via dual-luciferase reporter assay. Isoflurane pretreatment alleviated H/R-induced cell viability suppression and cell apoptosis promotion, which was accompanied by CASC15 downregulation. CASC15 overexpression abolished the influence of isoflurane on cardiomyocytes' viability and apoptosis. H/R-induced excessive release of TNF-α and IL-6 was hold down by isoflurane, which was re-activated after CASC15 overexpression. The concentration changes of both MDA and SOD by isoflurane were reversed by CASC15 overexpression. CASC15 functioned as miR-542-3p sponger, and miR-542-3p overexpression attenuated the effect of isoflurane and CASC15 on H/R-induced cardiac I/RI. Isoflurane pretreatment was beneficial for the alleviation of cardiac I/RI by inhibiting oxidative stress and myocardial inflammatory response. CASC15/miR-542-3p axis was required for isoflurane to exhibit its protective activity against cardiac I/RI.

Potential regulatory role of epigenetic modifications in aging-related heart failure

Heart failure (HF) is a serious clinical syndrome and a serious development or advanced stage of various heart diseases. Aging is an independent factor that causes pathological damage in cardiomyopathy and participates in the occurrence of HF at the molecular level by affecting mechanisms such as telomere shortening and mitochondrial dysfunction. Epigenetic changes have a significant impact on the aging process, and there is increasing evidence that genetic and epigenetic changes are key features of aging and aging-related diseases. Epigenetic modifications can affect genetic information by changing the chromatin state without changing the DNA sequence. Most of the genetic loci that are highly associated with cardiovascular diseases (CVD) are located in non-coding regions of the genome; therefore, the epigenetic mechanism of CVD has attracted much attention. In this review, we focus on the molecular mechanisms of HF during aging and epigenetic modifications mediating aging-related HF, emphasizing that epigenetic mechanisms play an important role in the pathogenesis of aging-related CVD and can be used as potential diagnostic and prognostic biomarkers, as well as therapeutic targets.

Unlocking the dark matter: noncoding RNAs and RNA modifications in cardiac aging

Cardiac aging is a multifaceted process that encompasses structural and functional alterations culminating in heart failure. As the elderly population continues to expand, there is a growing urgent need for interventions to combat age-related cardiac functional decline. Noncoding RNAs have emerged as critical regulators of cellular and biochemical processes underlying cardiac disease. This review summarizes our current understanding of how noncoding RNAs function in the heart during aging, with particular emphasis on mechanisms of RNA modification that control their activity. Targeting noncoding RNAs as potential novel therapeutics in cardiac aging is also discussed.

Mesenchymal stem cells-derived extracellular vesicle-incorporated H19 attenuates cardiac remodeling in rats with heart failure

Cardiac remodeling is manifested by hypertrophy and apoptosis of cardiomyocytes, resulting in the progression of cardiovascular diseases. Long noncoding RNAs (lncRNAs) serve as modifiers of cardiac remodeling. In this study, we aimed to explore the molecular mechanism of H19 shuttled by mesenchymal stem cells (MSC)-derived extracellular vesicles (EV) in cardiac remodeling upon heart failure (HF). Using the GEO database, H19, microRNA (miR)-29b-3p, and CDC42 were screened out as differentially expressed biomolecules in HF. H19 and CDC42 were elevated, and miR-29b-3p was decreased after MSC-EV treatment in rats subjected to ligation of the coronary artery. MSC-EV alleviated myocardial injury in rats with HF. H19 downregulation exacerbated myocardial injury, while miR-29b-3p inhibitor alleviated myocardial injury. By contrast, CDC42 downregulation aggravated the myocardial injury again. PI3K/AKT pathway was activated by MSC-EV. These findings provide insights into how H19 shuttled by EV mitigates cardiac remodeling through a competitive endogenous RNA network regarding miR-29b-3p and CDC42.

Expression Pattern and Molecular Mechanism of Oxidative Stress-Related Genes in Myocardial Ischemia-Reperfusion Injury

(1) Background: The molecular mechanism of oxidative stress-related genes (OSRGs) in myocardial ischemia-reperfusion injury (MIRI) has not been fully elucidated. (2) Methods: Differential expression analysis, enrichment analysis, and PPI analysis were performed on the MIRI-related datasets GSE160516 and GSE61592 to find key pathways and hub genes. OSRGs were obtained from the Molecular Signatures Database (MSigDB). The expression pattern and time changes of them were studied on the basis of their raw expression data. Corresponding online databases were used to predict miRNAs, transcription factors (TFs), and therapeutic drugs targeting common differentially expressed OSRGs. These identified OSRGs were further verified in the external dataset GSE4105 and H9C2 cell hypoxia-reoxygenation (HR) model. (3) Results: A total of 134 DEGs of MIRI were identified which were enriched in the pathways of "immune response", "inflammatory response", "neutrophil chemotaxis", "phagosome", and "platelet activation". Six hub genes and 12 common differentially expressed OSRGs were identified. A total of 168 miRNAs, 41 TFs, and 21 therapeutic drugs were predicted targeting these OSRGs. Lastly, the expression trends of Aif1, Apoe, Arg1, Col1a1, Gpx7, and Hmox1 were confirmed in the external dataset and HR model. (4) Conclusions: Aif1, Apoe, Arg1, Col1a1, Gpx7, and Hmox1 may be involved in the oxidative stress mechanism of MIRI, and the intervention of these genes may be a potential therapeutic strategy.

ALKBH5 ALLEVIATES HYPOXIA POSTCONDITIONING INJURY IN d -GALACTOSE-INDUCED SENESCENT CARDIOMYOCYTES BY REGULATING STAT3

ABSTRACT

Ischemic postconditioning (I/Post) reduces I/R injury by activating endogenous cardioprotection mechanisms, such as the JAK/signal transducer and activator of transcription 3 (STAT3) and PI3K/Akt pathways, which offer a traditional approach to myocardial protection. According to a previous study, cardioprotection by I/Post may be lost in aged mice, and in our previous research, hypoxic postconditioning (H/Post) lacked a protective effect in senescent cardiomyocytes, which was associated with low expression of long noncoding RNA H19. The N6-methyladenosine (m 6 A) modification is a dynamic and reversible process that has been confirmed to play a role in cardiovascular diseases. However, the mechanisms of m 6 A modification in myocardial I/Post remain to be explored. Neonatal cardiomyocytes were isolated from 2-day-old Sprague-Dawley rats, and senescence was induced by d -galactose, followed by stimulation of hypoxia-reoxygenation and H/Post. Hypoxic injury was evaluated by cell viability and the Bcl-2/Bax protein ratio. Total m 6 A levels were measured using a colorimetric m 6 A RNA Methylation Quantification Kit, and the m 6 A modified and differentially expressed mRNA was determined by MeRIP (methylated RNA immunoprecipitation). We found that H/Post increased m 6 A methylation and decreased RNA mA demethylase alkB homolog 5 (ALKBH5) expression in aged cardiomyocytes. Furthermore, ALKBH5 knockdown exacerbated injury following H/Post in senescent cardiomyocytes. In addition, ALKBH5 regulated STAT3 expression by mediating its m 6 A modification and long noncoding RNA H19/miR-124-3p. ALKBH5 also alleviated the H/Post injury induced by the low expression of STAT3 in senescent cardiomyocytes.

D-galactose-induced cardiac ageing: A review of model establishment and potential interventions

Cardiovascular disease (CVD) is highly prevalent in an ageing society. The increased incidence and mortality rates of CVD are global issues endangering human health. There is an urgent requirement for understanding the aetiology and pathogenesis of CVD and developing possible interventions for preventing CVD in ageing hearts. It is necessary to select appropriate models and treatment methods. The D‐galactose‐induced cardiac ageing model possesses the advantages of low mortality, short time and low cost and has been increasingly used in the study of cardiovascular diseases in recent years. Therefore, understanding the latest progress in D‐galactose‐induced cardiac ageing is valuable. This review highlights the recent progress and potential therapeutic interventions used in D‐galactose‐induced cardiac ageing in recent years by providing a comprehensive summary of D‐galactose‐induced cardiac ageing in vivo and in vitro. This review may serve as reference literature for future research on age‐related heart diseases.

Infarct-preconditioning exosomes of umbilical cord mesenchymal stem cells promoted vascular remodeling and neurological recovery after stroke in rats

Background

Stroke is the leading cause of disability worldwide, resulting in severe damage to the central nervous system and disrupting neurological functions. There is no effective therapy for promoting neurological recovery. Growing evidence suggests that the composition of exosomes from different microenvironments may benefit stroke. Therefore, it is reasonable to assume that exosomes secreted in response to infarction microenvironment could have further therapeutic effects.

Methods

In our study, cerebral infarct tissue extracts were used to pretreat umbilical cord mesenchymal stem cells (UCMSC). Infarct-preconditioned exosomes were injected into rats via tail vein after middle cerebral artery occlusion (MCAO). The effect of infarct-preconditioned exosomes on the neurological recovery of rats was examined using Tunel assay, 2,3,5-triphenyltetrazolium chloride (TTC) assay, magnetic resonance imaging (MRI) analyses, modified Neurological Severity Score (mNSS), Morris water maze (MWM), and vascular remodeling analysis. Mi-RNA sequencing and functional enrichment analysis were used to validate the signal pathway involved in the effect of infarct-preconditioned exosomes. Human umbilical vein endothelial cells (HUVECs) were co-cultured with the isolated exosomes. Cell Counting Kit-8 (CCK-8) assay, scratch healing, and Western blot analysis were used to detect the biological behavior of HUVECs.

Results

The results showed that compared with normal exosomes, infarct-preconditioned exosomes further promoted vascular remodeling and recovery of neurological function after stroke. The function of upregulated miRNAs and their target genes which is beneficial to vascular smooth muscle cells verified the importance of vascular remodeling in improving stroke. Better resistance to oxygen–glucose deprivation/reoxygenation (OGD/R), reduced apoptosis, and enhanced migration were observed in infarct-preconditioned exosomes-treated umbilical vein endothelial cells.

Conclusions

Our results demonstrated that infarct-preconditioned exosomes promoted neurological recovery after stroke by enhancing vascular endothelial remodeling, suggested that infarct-preconditioned exosomes could be a novel way to alleviate brain damage following a stroke.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03083-9.

Mechanisms Underlying Abnormal Expression of lncRNA H19 in Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

Hypoxic-ischemic (HI)-related brain injury, especially HI encephalopathy (HIE) is a leading cause of morbidity and disability in newborns. Long noncoding RNAs (lncRNAs) are implicated in the progress of HI brain damage. However, the mechanisms underlying the regulatory effects of lncRNA H19 on autophagy in HIE remain unknown. This study was designed to identify the potential mechanisms involving lncRNA H19 in HIE.

STUDY DESIGN

We selected three HIE newborns and three healthy newborns for neonatal behavioral neurological assessment and screened the differentially expressed lncRNAs by microarray analysis and detected H19 expression in serum. After that, neonatal HIE rats were established and injected with H19 overexpression lentivirus vector or autophagy activator Rapa. The structure and apoptotic levels of brain tissue were observed, and righting reflex and geotaxis reflex were utilized to evaluate the short-term neurological function of HIE rats. The Morris water maze was performed to measure the long-term neurological functions of HIE rats. The binding relationships among H19/miR-19b/protein kinase B3 (Akt3) were verified. Levels of Akt3- and autophagy-related proteins were measured.

RESULTS

H19 was upregulated in HIE newborns and rat models. The areas of cerebral infarction and apoptosis in neonatal HIE rats were increased, and the nerve functions were compromised. The overexpression of H19 alleviated nerve damage of neonatal HIE rats, and reduced autophagy of brain tissue. H19 upregulated Akt3 as a miR-29b sponge. The protective effects of overexpression of H19 on brain tissue and nerve functions of neonatal HIE rats were partially reversed by autophagy activator.

CONCLUSION

H19 improved the brain tissue and alleviated nerve damage of neonatal HIE rats by upregulating the Akt3/mTOR pathway as a miR-29b sponge.

KEY POINTS

· H19 overexpression reduces the nerve damage in neonatal HIE rats.. · H19 reduces autophagy in neonatal HIE rats by the miR-29b/Akt3/mTOR axis.. · Autophagy activator reverses the protection of H19 in neonatal HIE..

An update on the functional roles of long non‑coding RNAs in ischemic injury (Review)

Ischemic injuries result from ischemia and hypoxia in cells. Tissues and organs receive an insufficient supply of nutrients and accumulate metabolic waste, which leads to the development of inflammation, fibrosis and a series of other issues. Ischemic injuries in the brain, heart, kidneys, lungs and other organs can cause severe adverse effects. Acute renal ischemia induces acute renal failure, heart ischemia induces myocardial infarction and cerebral ischemia induces cerebrovascular accidents, leading to loss of movement, consciousness and possibly, life-threatening disabilities. Existing evidence suggests that long non-coding RNAs (lncRNAs) are regulatory sequences involved in transcription, post-transcription, epigenetic regulation and multiple physiological processes. lncRNAs have been shown to be differentially expressed following ischemic injury, with the severity of the ischemic injury being affected by the upregulation or downregulation of certain types of lncRNA. The present review article provides an extensive summary of the functional roles of lncRNAs in ischemic injury, with a focus on the brain, heart, kidneys and lungs. The present review mainly summarizes the functional roles of lncRNA MALAT1, lncRNA MEG3, lncRNA H19, lncRNA TUG1, lncRNA NEAT1, lncRNA AK139328 and lncRNA CAREL, among which lncRNA MALAT1, in particular, plays a crucial role in ischemic injury and is currently a hot research topic.

Noncoding RNAs in age-related cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in the adult population worldwide and represent a severe economic burden and public health concern. The majority of human genes do not code for proteins. However, noncoding transcripts play important roles in ageing that significantly increases the risk for CVDs. Noncoding RNAs (ncRNAs) are critical regulators of multiple biological processes related to ageing such as oxidative stress, mitochondrial dysfunction and chronic inflammation. NcRNAs are also involved in pathophysiological developments within the cardiovascular system including arrhythmias, cardiac hypertrophy, fibrosis, myocardial infarction and heart failure. In this review article, we cover the roles of ncRNAs in cardiovascular ageing and disease as well as their potential therapeutic applications in CVDs.

FGF21 alleviates pulmonary hypertension by inhibiting mTORC1/EIF4EBP1 pathway via H19

Long non‐coding RNAs (lncRNAs) play a significant role in pulmonary hypertension (PH). Our preliminary data showed that hypoxia‐induced PH is attenuated by fibroblast growth factor 21 (FGF21) administration. Therefore, we further investigated the regulatory role of long non‐coding RNAs in PH treated with FGF21. RNA sequencing analysis and real‐time PCR identified a significantly up‐regulation of the H19 after FGF21 administration. Moreover, gain‐ and loss‐of‐function assays demonstrated that FGF21 suppressed hypoxia‐induced proliferation of pulmonary artery smooth muscle cells partially through upregulation of H19. In addition, FGF21 deficiency markedly exacerbated hypoxia‐induced increases of pulmonary artery pressure and pulmonary vascular remodelling. In addition, AAV‐mediated H19 overexpression reversed the malignant phenotype of FGF21 knockout mice under hypoxia expose. Further investigation uncovered that H19 also acted as an orchestra conductor that inhibited the function of mechanistic target of rapamycin complex 1 (mTORC1) by disrupting the interaction of mTORC1 with eukaryotic translation initiation factor 4E–binding protein 1 (EIF4EBP1). Our work highlights the important role of H19 in PH treated with FGF21 and suggests a mechanism involving mTORC1/EIF4EBP1 inhibition, which may provide a fundamental for clinical application of FGF21 in PH.

Artemisinin relieves myocardial ischemia-reperfusion injury via modulating miR-29b-3p and hemicentin 1

Objective: To explore the impact of artemisinin (ARS) on myocardial ischemia-reperfusion (I/R) injury and the underlying mechanism. Methods: Myocardial I/R rat model and cell model were used in this study. The cell viability, morphological changes, apoptosis, and oxidative stress were evaluated in cardiomyocytes H9c2 cells in vitro by using cell counting kit-8, microscope, flow cytometry, and commercial kits. High throughput sequencing is used to identify molecular targets of ARS on myocardial I/R injury, and then the gene-gene interaction network was constructed. MiR-29b-3p, hemicentin 1 (HMCN1), and apoptosis-related genes were tested by qRT-PCR and Western blotting. In the myocardial I/R rat model, echocardiography, (Triphenyl tetrazolium chloride) TTC staining, Hematoxylin-eosin (H&E) staining, Masson Trichrome staining, and TUNEL staining are applied to evaluate the protective effect of ARS on the myocardial injury. Results: In vitro, we demonstrated that ARS alleviated H₂O₂-induced myocardial I/R injury, manifested by increased H9c2 viability, decreased pathological changes, apoptosis, and oxidative stress biomarker ROS, LDH, and CK-MB. Then, sequencing analysis revealed that miR-29b-3p/HMCN1 was the target of ARS for myocardial I/R injury. Notably, rescue experiments indicated that ARS inhibited myocardial I/R injury through targeted regulation miR-29b-3p/HMCN1. In vivo, we confirmed that ARS reduced myocardial injury, fibrosis, and apoptosis via modulation of miR-29b-3p/HMCN1. Conclusion: This study demonstrated the functional role of the ARS/miR-29b-3p/HMCN1 axis in alleviating myocardial I/R injury, which provided a new direction for myocardial I/R injury therapy.

Impact of the Main Cardiovascular Risk Factors on Plasma Extracellular Vesicles and Their Influence on the Heart's Vulnerability to Ischemia-Reperfusion Injury

The majority of cardiovascular deaths are associated with acute coronary syndrome, especially ST-elevation myocardial infarction. Therapeutic reperfusion alone can contribute up to 40 percent of total infarct size following coronary artery occlusion, which is called ischemia-reperfusion injury (IRI). Its size depends on many factors, including the main risk factors of cardiovascular mortality, such as age, sex, systolic blood pressure, smoking, and total cholesterol level as well as obesity, diabetes, and physical effort. Extracellular vesicles (EVs) are membrane-coated particles released by every type of cell, which can carry content that affects the functioning of other tissues. Their role is essential in the communication between healthy and dysfunctional cells. In this article, data on the variability of the content of EVs in patients with the most prevalent cardiovascular risk factors is presented, and their influence on IRI is discussed.

The Functions of LncRNA H19 in the Heart

Cardiovascular diseases (CVDs) are major causes of morbidity and mortality worldwide. Great effort has been put into exploring early diagnostic biomarkers and innovative therapeutic strategies for preventing CVD progression over the last two decades. Long non-coding RNAs (lncRNAs) have been identified as novel regulators in cardiac development and cardiac pathogenesis. For example, lncRNA H19 (H19), also known as a fetal gene abundant in adult heart and skeletal muscles and evolutionarily conserved in humans and mice, has a regulatory role in aortic aneurysm, myocardial hypertrophy, extracellular matrix reconstitution, and coronary artery diseases. Yet, the exact function of H19 in the heart remains unknown. This review summarises the functions of H19 in the heart and discusses the challenges and possible strategies of H19 research for cardiovascular disease.

Exosomes from Human Umbilical Vein Endothelial Cells Ameliorate Ischemic Injuries by Suppressing the RNA Component of Mitochondrial RNA-processing Endoribonuclease via the Induction of miR-206/miR-1-3p Levels

Exosomes might mediate the effects of remote ischemic post-conditioning (RIPostC) treatment on vital organs. The present study aimed to explore the role of RNA component of mitochondrial RNA-processing endoribonuclease (RMRP) in the effects of human umbilical vein endothelial cell (HUVEC)-derived exosomes on ischemic injuries in vitro and in vivo. HUVECs were subjected to oxygen-glucose deprivation (OGD) treatment and exosomes were collected OGD-treated human neural cells were incubated with HUVEC-derived exosomes. Changes in cell viability, apoptosis, and RMRP-mediated PI3K/Akt/mTOR pathway activity were detected. The role of RMRP inhibition in the anti-OGD effects of exosomes was further determined by upregulating RMRP expression in human neural cells. The potential RMRP inhibitory factors in exosomes were explored using microarray detection. The effects of exosomes were validated with MCAO mouse models. In OGD neurons incubated with the exosomes, cell viability was improved and cell apoptosis was suppressed. At molecular level, exosomes on downregulated RMRP, p-PI3K, p-Akt, and p-mTOR, while induced eNOS. After the overexpression of RMRP, the cell protective effects of exosomes were counteracted, which was associated with the re-activation of PI3K/Akt/mTOR pathway. Based on the detection of microarray, the induced levels of miR-206 and miR-1-3p by OGD in HVUECs contributed to the RMPR inhibition. Additionally, injection of exosomes restricted infarction area and suppressed RMRP in MCAO mice. Collectively, exosomes from OGD HUVECs could protect neurons against ischemia-induced injuries, and the effects were associated with the suppression of RMRP in neurons via distance transfer of miR-206 and miR-1-3p.

Identification and Roles of miR-29b-1-3p and miR29a-3p-Regulated and Non-Regulated lncRNAs in Endocrine-Sensitive and Resistant Breast Cancer Cells

Despite improvements in the treatment of endocrine-resistant metastatic disease using combination therapies in patients with estrogen receptor α (ERα) primary tumors, the mechanisms underlying endocrine resistance remain to be elucidated. Non-coding RNAs (ncRNAs), including microRNAs (miRNA) and long non-coding RNAs (lncRNA), are targets and regulators of cell signaling pathways and their exosomal transport may contribute to metastasis. Previous studies have shown that a low expression of miR-29a-3p and miR-29b-3p is associated with lower overall breast cancer survival before 150 mos. Transient, modest overexpression of miR-29b1-3p or miR-29a-3p inhibited MCF-7 tamoxifen-sensitive and LCC9 tamoxifen-resistant cell proliferation. Here, we identify miR-29b-1/a-regulated and non-regulated differentially expressed lncRNAs in MCF-7 and LCC9 cells using next-generation RNA seq. More lncRNAs were miR-29b-1/a-regulated in LCC9 cells than in MCF-7 cells, including DANCR, GAS5, DSCAM-AS1, SNHG5, and CRND. We examined the roles of miR-29-regulated and differentially expressed lncRNAs in endocrine-resistant breast cancer, including putative and proven targets and expression patterns in survival analysis using the KM Plotter and TCGA databases. This study provides new insights into lncRNAs in endocrine-resistant breast cancer.

MiR-29b-3p aggravates cardiac hypoxia/reoxygenation injury via targeting PTX3

Our current research aimed to decipher the role and underlying mechanism with regard to miR-29b-3p involving in myocardial ischemia/reperfusion (I/R) injury. In the present study, cardiomyocyte H9c2 cell was used, and hypoxia/reoxygenation (H/R) model was established to mimic the myocardial I/R injury. The expressions of miR-29b-3p and pentraxin 3 (PTX3) were quantified deploying qRT-PCR and Western blot, respectively. The levels of LDH, TNF-α, IL-1β and IL-6 were detected to evaluate cardiomyocyte apoptosis and inflammatory response. Cardiomyocyte viability and apoptosis were examined employing CCK-8 assay and flow cytometry, respectively. Verification of the targeting relationship between miR-29b-3p and PTX3 was conducted using a dual-luciferase reporter gene assay. It was found that miR-29b-3p expression in H9c2 cells was up-regulated by H/R, and a remarkable down-regulation of PTX3 expression was demonstrated. MiR-29b-3p significantly promoted of release of inflammatory cytokines of H9c2 cells, and it also constrained the proliferation and promoted the apoptosis of H9c2 cells. Additionally, PTX3 was inhibited by miR-29b-3p at both mRNA and protein levels, and it was identified as a direct target of miR-29b-3p. PTX3 overexpression could reduce the inflammatory response, increase the viability of H9c2 cells, and inhibit apoptosis. Additionally, PTX3 counteracted the function of miR-29b-3p during the injury of H9c2 cells induced by H/R. In summary, miR-29b-3p was capable of aggravating the H/R injury of H9c2 cells by repressing the expression of PTX3.

Implication of regulatory networks of long noncoding RNA/circular RNA-miRNA-mRNA in diabetic cardiovascular diseases

Diabetic cardiovascular diseases (DCVDs) are the most common complications of diabetes mellitus and are considered to be one of the most important threats to global health and an economic burden. Long noncoding RNA (lncRNA), circular RNA (circRNA), and miRNA are a novel group of noncoding RNAs that are involved in the regulation of various pathophysiological processes, including DCVDs. Interestingly, both lncRNA and circRNA can act as competing endogenous RNA of miRNA, thereby regulating the expression of the target mRNA by decoying or sponging the miRNA. In this review, we focus on the mechanistic, pathological and functional roles of lncRNA/circRNA-miRNA-mRNA networks in DCVDs and further discuss the potential implications for early detection, therapeutic intervention and prognostic evaluation.

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.

Platelet lysate induces chondrogenic differentiation of umbilical cord-derived mesenchymal stem cells by regulating the lncRNA H19/miR-29b-3p/SOX9 axis

Platelet lysate (PL) has been shown to induce chondrogenic differentiation of human umbilical cord‐derived mesenchymal stem cells (hUCMSCs). However, the underlying mechanism is still not clear. The aim of this study was to investigate whether long noncoding RNA H19 is involved in this process. hUCMSCs were isolated, identified and cultured in 5% PL‐supplemented chondrogenic differentiation medium. Chondrogenic differentiation was assessed by Alcian blue staining. The expressions of H19, miR‐29b‐3p, SRY‐related high‐mobility‐group box 9 (SOX9), collagen II and aggrecan were determined by quantitative real‐time PCR and western blot. The interaction between miR‐29b‐3p and H19 or SOX9 was analyzed by luciferase reporter assay. During PL‐induced chondrogenic differentiation of hUCMSCs, expressions of H19 and SOX9 were increased, whereas miR‐29b‐3p expression was decreased. H19 overexpression promoted, whereas H19 silencing attenuated the PL‐induced chondrogenic differentiation of hUCMSCs. SOX9 was identified as a direct target of miR‐29b‐3p, and H19 was observed to act as a sponge of miR‐29b‐3p to up‐regulate SOX9 expression. The chondrogenic differentiation‐promoting effect of H19 overexpression was negated when miR‐29b‐3p expression was up‐regulated by Lenti‐miR‐29b‐3p infection. In conclusion, PL induced chondrogenic differentiation of hUCMSCs by regulating the H19/miR‐29b‐3p/SOX9 axis.

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.

LncRNA H19 is involved in myocardial ischemic preconditioning via increasing the stability of nucleolin protein

Myocardial ischemic preconditioning (IP) is defined as a brief period of myocardial ischemia/reperfusion (I/R) that significantly reduces injury during the subsequent exposure to long-term I/R. However, the underlying mechanisms of myocardial IP are yet to be elucidated. This study investigated the expression and roles of long noncoding RNA (lncRNA) H19 in myocardial IP in vitro and in vivo. LncRNA H19 expression levels were analyzed by quantitative reverse-transcription polymerase chain reaction, cell viability was determined by the Cell Counting Kit-8 assay, apoptosis was evaluated based on the caspase 3 activity, and RNA immunoprecipitation was performed to examine the interaction between lncRNA H19 and nucleolin. The results of this study showed that lncRNA H19 expression was significantly upregulated in mouse hearts subjected to myocardial IP, in rat H9C2 cells exposed to H2 O2 preconditioning (H2 O2 -PC), and in neonatal rat cardiomyocytes subjected to hypoxia preconditioning. H19 knockdown abrogated the H2 O2 -PC-mediated protection in cardiomyocytes evidenced by the decreased cell viability and increased caspase-3 activity. Conversely, H19 overexpression enhanced the protective role of H2 O2 -PC in cardiomyocytes. In addition, H19 overexpression increased the expression of nucleolin, whereas H19 ablation abrogated H2 O2 -PC-induced upregulation of nucleolin in cardiomyocytes. Furthermore, H19 overexpression increased the stabilization of nucleolin; an interaction between H19 and nucleolin was identified using the RNA-protein interaction studies. Furthermore, nucleolin small interfering RNA relieved the protective role of lncRNA H19. These findings demonstrated that the lncRNA H19 is involved in myocardial IP via increasing the stability of nucleolin protein and lncRNA H19 may represent a potential therapeutic target for the treatment of the myocardial injury.

Long non-coding RNA H19 in atherosclerosis: what role?

Atherosclerosis (AS) is widely accepted to be a multistep pathophysiological process associated with several other processes such as angiogenesis and inflammatory response. Long non-coding RNAs (lncRNAs) are non-protein coding RNAs (more than 200 nucleotides in length) and can regulate gene expression at the transcriptional and post-transcriptional levels. Recent studies suggest that lncRNA-H19 plays important roles in the regulation of angiogenesis, adipocyte differentiation, lipid metabolism, inflammatory response, cellular proliferation and apoptosis. In this review, we primarily discuss the roles of lncRNA-H19 in atherosclerosis-related pathophysiological processes and the potential mechanisms by which lncRNA-H19 regulates the development of atherosclerosis, to help provide a better understanding of the biological functions of lncRNA-H19 in atherosclerosis.

Long non‑coding RNA H19 protects H9c2 cells against hypoxia‑induced injury by activating the PI3K/AKT and ERK/p38 pathways

Myocardial ischemia/reperfusion injury often leads to adverse cardiovascular outcomes due to severe hypoxia. The present study aimed to evaluate the effects and mechanism of long non-coding RNA H19 (H19) on rat H9c2 cells with hypoxia-induced injury. H9c2 cells were infected with lentiviruses to express H19 or H19-targeting short hairpin RNA (shRNA), or their respective controls, at a multiplicity of infection of 1:100. H19 expression was determined by reverse transcription-quantitative PCR. Hypoxic injury was induced and assessed by analyzing the level of apoptosis, the cell cycle distribution and the mitochondrial membrane potential using flow cytometry in the different groups. The expression of the PI3K/AKT and the ERK/p38 signaling pathways were analyzed using western blotting. It was found that hypoxia stimulated apoptosis, induced G1 phase cell cycle arrest and increased the mitochondrial depolarization rate in H9c2 cells. When compared with the hypoxic model group, the H19 overexpression group had a significantly reduced rate of apoptosis (P=0.016), a smaller G1 population and a higher S phase population (P=0.018 and P=0.031, respectively), and a reduced mitochondrial depolarization rate (P=0.036). By contrast, the H19 shRNA group exhibited the opposite trends, suggesting that hypoxia-induced injury was alleviated by the overexpression of H19 and was aggravated by the knockdown of H19. The present mechanistic studies revealed that H19 may decrease hypoxia-induced cell injury by activating the PI3K/AKT and ERK/p38 pathways. The results of the present study suggested that H19 may alleviate hypoxia-induced myocardial cell injury through the activation of the PI3K/AKT and ERK/p38 pathways.

Targeting Age-Related Pathways in Heart Failure

During aging, deterioration in cardiac structure and function leads to increased susceptibility to heart failure. The need for interventions to combat this age-related cardiac decline is becoming increasingly urgent as the elderly population continues to grow. Our understanding of cardiac aging, and aging in general, is limited. However, recent studies of age-related decline and its prevention through interventions like exercise have revealed novel pathological and cardioprotective pathways. In this review, we summarize recent findings concerning the molecular mechanisms of age-related heart failure and highlight exercise as a valuable experimental platform for the discovery of much-needed novel therapeutic targets in this chronic disease.

Dexmedetomidine Postconditioning Alleviates Hypoxia/Reoxygenation Injury in Senescent Myocardial Cells by Regulating lncRNA H19 and m6A Modification

H19, a long noncoding RNA (lncRNA), reportedly protects myocardial cells (H9c2 cell line) against hypoxia-reoxygenation- (H/R-) induced injury. Dexmedetomidine (Dex) has an important myocardial protective effect, although its function and mechanism in cardiac ischemia/reperfusion (I/R) injury, especially for senile patients, requires further study. RNA N6-methyladenosine (m6A) is the most abundant endogenous RNA modification. However, the effect of Dex postconditioning on RNA m6A modification has rarely been reported. The aim of this study was to evaluate roles of H19 and m6A modification in Dex postconditioning of aged cardiomyocytes. Hydrogen peroxide (H2O2) was used to induce senescence of H9c2 cells. After 6 h of hypoxia, H9c2 cells were exposed to different concentrations of dexmedetomidine (0, 500 nM, 1 μM, and 2 μM) for 6 h. After knockdown or overexpression of H19 and its downstream gene miR-29b-3p and cellular inhibitor of apoptosis protein 1 (cIAP1), Dex postconditioning experiments were performed to examine effects on myocardial cell injury. Global m6A levels after H/R with or without Dex postconditioning were measured with a colorimetric m6A RNA Methylation Quantification Kit. The mechanism by which RNA m6A methylation regulated genes mediating H19 expression was verified by m6A RNA immunoprecipitation (MeRIP), and the function of Dex postconditioning of aged cardiomyocytes was investigated. Dex postconditioning protected against H/R-induced injury of aged myocardial cells through H19/miR-29b-3p/cIAP1, increased methylation of RNA m6A elicited by H/R, and attenuated H/R-induced injury by suppressing expression of the RNA m6A demethylase gene alkB homolog 5 (ALKBH5). In addition, AKLBH5 regulated the expression of H19, and Dex postconditioning attenuated H/R-induced injury via ALKBH5 in aged cardiomyocytes.

LncRNA H19 ameliorates myocardial infarction-induced myocardial injury and maladaptive cardiac remodelling by regulating KDM3A

Myocardial infarction (MI) remains the leading cause of morbidity and mortality worldwide, and novel therapeutic targets still need to be investigated to alleviate myocardial injury and the ensuing maladaptive cardiac remodelling. Accumulating studies have indicated that lncRNA H19 might exert a crucial regulatory effect on cardiovascular disease. In this study, we aimed to explore the biological function and molecular mechanism of H19 in MI. To investigate the biological functions of H19, miRNA-22-3p and KDM3A, gain- and loss-of-function experiments were performed. In addition, bioinformatics analysis, dual-luciferase reporter assays, RNA immunoprecipitation (RIP) assays, RNA pull-down assays, quantitative RT-PCR and Western blot analyses as well as rescue experiments were conducted to reveal an underlying competitive endogenous RNA (ceRNA) mechanism. We found that H19 was significantly down-regulated after MI. Functionally, enforced H19 expression dramatically reduced infarct size, improved cardiac performance and alleviated cardiac fibrosis by mitigating myocardial apoptosis and decreasing inflammation. However, H19 knockdown resulted in the opposite effects. Bioinformatics analysis and dual-luciferase assays revealed that, mechanistically, miR-22-3p was a direct target of H19, which was also confirmed by RIP and RNA pull-down assays in primary cardiomyocytes. In addition, bioinformatics analysis and dual-luciferase reporter assays also demonstrated that miRNA-22-3p directly targeted the KDM3A gene. Moreover, subsequent rescue experiments further verified that H19 regulated the expression of KDM3A to ameliorate MI-induced myocardial injury in a miR-22-3p-dependent manner. The present study revealed the critical role of the lncRNAH19/miR-22-3p/KDM3A pathway in MI. These findings suggest that H19 may act as a potential biomarker and therapeutic target for MI.

Insight into long noncoding RNA-miRNA-mRNA axes in myocardial ischemia-reperfusion injury: the implications for mechanism and therapy

Emerging evidence has demonstrated that regulatory noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs) and miRNAs, play crucial roles in the initiation and progress of myocardial ischemia-reperfusion injury (MIRI), which is associated with autophagy, apoptosis and necrosis of cardiomyocytes, as well as oxidative stress, inflammation and mitochondrial dysfunction. LncRNAs serve as a precursor or host of miRNAs and directly/indirectly affecting miRNAs via competitive binding or sponge effects. Simultaneously, miRNAs post-transcriptionally regulate the expression of genes by targeting various mRNA sequences due to their imperfect pairing with mRNAs. This review summarizes the potential regulatory role of lncRNA-miRNA-mRNA axes in MIRI and related molecular mechanisms of cardiac disorders, also provides insight into the potential therapies for MIRI-induced diseases.

Long Non-coding RNA H19 Suppression Protects the Endothelium Against Hyperglycemic-Induced Inflammation via Inhibiting Expression of miR-29b Target Gene Vascular Endothelial Growth Factor a Through Activation of the Protein Kinase B/Endothelial Nitric Oxide Synthase Pathway

It has been shown that non-coding RNAs (ncRNAs) play an important regulatory role in pathophysiological processes involving inflammation. The vascular endothelial growth factor A (VEGFA) gene also participates in the inflammatory process. However, the relationships between ncRNAs and VEGFA are currently unclear. Here, this study was designed to determine the relationship between long non-coding RNA (lncRNA) H19, mircoRNA29b (miR-29b), and VEGFA in the development of diabetes mellitus (DM). We demonstrate that H19 is upregulated and miR-29b downregulated in individuals with DM and directly binds miR-29b. VEGFA is the target of miR-29b in the vascular endothelium of individuals with DM. We found that positive modulation of miR29b and inhibition of H19 and VEGFA significantly attenuates high glucose-induced endothelial inflammation and oxidative stress. We also found that the protein kinase B/endothelial nitric oxide synthase (AKT/eNOS) signal pathway in endothelial cells is activated through regulation of miR29b and H19 endogenous RNAs. We conclude that H19 suppression protects the endothelium against high glucose-induced inflammation and oxidative stress in endothelial cells by upregulation of miR-29b and downregulation of VEGFA through AKT/eNOS signal pathway activation. These results suggest a novel link between dysregulated ncRNA expression, inflammation, and the signaling pathway in the vascular endothelium of individuals with DM, indicating a promising strategy for preventing cardiovascular disease in such individuals.

Differential chamber-specific expression and regulation of long non-coding RNAs during cardiac development

Cardiovascular development is governed by a complex interplay between inducting signals such as Bmps and Fgfs leading to activation of cardiac specific transcription factors such as Nkx2.5, Mef2c and Srf that orchestrate the initial steps of cardiogenesis. Over the last decade we have witnessed the discovery of novel layers of gene regulation, i.e. post-transcriptional regulation exerted by non-coding RNAs. The function role of small non coding RNAs has been widely demonstrated, e.g. miR-1 knockout display several cardiovascular abnormalities during embryogenesis. More recently long non-coding RNAs have been also reported to modulate gene expression and function in the developing heart, as exemplified by the embryonic lethal phenotypes of Fendrr and Braveheart knock out mice, respectively. In this study, we investigated the differential expression profile during cardiogenesis of previously reported lncRNAs in heart development. Our data revealed that Braveheart, Fendrr, Carmen display a preferential adult expression while Miat, Alien, H19 preferentially display chamber-specific expression at embryonic stages. We also demonstrated that these lncRNAs are differentially regulated by Nkx2.5, Srf and Mef2c, Pitx2 > Wnt > miRNA signaling pathway and angiotensin II and thyroid hormone administration. Importantly isoform-specific expression and distinct nuclear vs cytoplasmic localization of Braveheart, Carmen and Fendrr during chamber morphogenesis is observed, suggesting distinct functional roles of these lncRNAs in atrial and ventricular chambers. Furthermore, we demonstrate by in situ hybridization a dynamic epicardial, myocardial and endocardial expression of H19 during cardiac development. Overall our data support novel roles of these lncRNAs in different temporal and tissue-restricted fashion during cardiogenesis.

Long Noncoding Competing Endogenous RNA Networks in Age-Associated Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the most serious health problem in the world, displaying high rates of morbidity and mortality. One of the main risk factors for CVDs is age. Indeed, several mechanisms are at play during aging, determining the functional decline of the cardiovascular system. Aging cells and tissues are characterized by diminished autophagy, causing the accumulation of damaged proteins and mitochondria, as well as by increased levels of oxidative stress, apoptosis, senescence and inflammation. These processes can induce a rapid deterioration of cellular quality-control systems. However, the molecular mechanisms of age-associated CVDs are only partially known, hampering the development of novel therapeutic strategies. Evidence has emerged indicating that noncoding RNAs (ncRNAs), such as long ncRNAs (lncRNAs) and micro RNAs (miRNAs), are implicated in most patho-physiological mechanisms. Specifically, lncRNAs can bind miRNAs and act as competing endogenous-RNAs (ceRNAs), therefore modulating the levels of the mRNAs targeted by the sponged miRNA. These complex lncRNA/miRNA/mRNA networks, by regulating autophagy, apoptosis, necrosis, senescence and inflammation, play a crucial role in the development of age-dependent CVDs. In this review, the emerging knowledge on lncRNA/miRNA/mRNA networks will be summarized and the way in which they influence age-related CVDs development will be discussed.

Long noncoding RNA/circular noncoding RNA-miRNA-mRNA axes in cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Non-coding RNAs including long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs) have been reported to participate in pathological developments of CVDs through various mechanisms. Among them, the networks among lncRNAs/circRNAs, miRNAs, and mRNAs have recently attracted attention. Understanding the molecular mechanism could aid the discovery of therapeutic targets or strategies in CVDs including atherosclerosis, myocardial infarction (MI), hypertrophy, heart failure (HF) and cardiomyopathy. In this review, we summarize the latest research involving the lncRNA/circRNA-miRNA-mRNA axis in CVDs, with emphasis on the molecular mechanism.

Non-Coding RNAs in Breast Cancer: Intracellular and Intercellular Communication

Non-coding RNAs (ncRNAs) are regulators of intracellular and intercellular signaling in breast cancer. ncRNAs modulate intracellular signaling to control diverse cellular processes, including levels and activity of estrogen receptor α (ERα), proliferation, invasion, migration, apoptosis, and stemness. In addition, ncRNAs can be packaged into exosomes to provide intercellular communication by the transmission of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) to cells locally or systemically. This review provides an overview of the biogenesis and roles of ncRNAs: small nucleolar RNA (snRNA), circular RNAs (circRNAs), PIWI-interacting RNAs (piRNAs), miRNAs, and lncRNAs in breast cancer. Since more is known about the miRNAs and lncRNAs that are expressed in breast tumors, their established targets as oncogenic drivers and tumor suppressors will be reviewed. The focus is on miRNAs and lncRNAs identified in breast tumors, since a number of ncRNAs identified in breast cancer cells are not dysregulated in breast tumors. The identity and putative function of selected lncRNAs increased: nuclear paraspeckle assembly transcript 1 (NEAT1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), steroid receptor RNA activator 1 (SRA1), colon cancer associated transcript 2 (CCAT2), colorectal neoplasia differentially expressed (CRNDE), myocardial infarction associated transcript (MIAT), and long intergenic non-protein coding RNA, Regulator of Reprogramming (LINC-ROR); and decreased levels of maternally-expressed 3 (MEG3) in breast tumors have been observed as well. miRNAs and lncRNAs are considered targets of therapeutic intervention in breast cancer, but further work is needed to bring the promise of regulating their activities to clinical use.