Overexpression of circRNA SNRK targets miR-103-3p to reduce apoptosis and promote cardiac repair through GSK3β/β-catenin pathway in rats with myocardial infarction

Molecular gatekeepers of endogenous adult mammalian cardiomyocyte proliferation

Irreversible cardiac fibrosis, cardiomyocyte death and chronic cardiac dysfunction after myocardial infarction pose a substantial global health-care challenge, with no curative treatments available. To regenerate the injured heart, cardiomyocytes must proliferate to replace lost myocardial tissue - a capability that adult mammals have largely forfeited to adapt to the demanding conditions of life. Using various preclinical models, our understanding of cardiomyocyte proliferation has progressed remarkably, leading to the successful reactivation of cell cycle induction in adult animals, with functional recovery after cardiac injury. Central to this success is the targeting of key pathways and structures that drive cardiomyocyte maturation after birth - nucleation and ploidy, sarcomere structure, developmental signalling, chromatin and epigenetic regulation, the microenvironment and metabolic maturation - forming a complex regulatory framework that allows efficient cellular contraction but restricts cardiomyocyte proliferation. In this Review, we explore the molecular pathways underlying these core mechanisms and how their manipulation can reactivate the cell cycle in cardiomyocytes, potentially contributing to cardiac repair.

Inhibition of circALPK2 enhances proliferation and therapeutic potential of human pluripotent stem cell-derived cardiomyocytes in myocardial infarction

BACKGROUND

Understanding the mechanisms regulating human cardiomyocyte proliferation holds significant promise for developing effective therapies to enhance cardiac regeneration and repair. This study investigates the role of circALPK2, a circular RNA derived from the back-splicing of the 4th exon of alpha protein kinase 2 (ALPK2), in regulating cardiomyocyte proliferation and its therapeutic efficacy in myocardial infarction (MI) treatment.

METHODS

Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) were used to assess the expression and function ofcircALPK2. Lentiviral shRNA-mediated knockdown of circALPK2 was performed in hESC-CMs, followed by RNA sequencing to identify targeted genes and biological processes. The proliferative capacity of wild-type and circALPK2 knockdown hESC-CMs was evaluated using CCK-8 assay, EdU staining and RT-qPCR analysis of cell cycle-related genes. Dual luciferase assays were conducted to validate the predicted miRNA targets and their downstream effects. For in vivo evaluation, MI mice were injected with either wild-type or circALPK2 knockdown hESC-CMs, and the therapeutic potential was assessed by echocardiographic and histological analyses.

RESULTS

We identified circALPK2 as a negative regulator of cell proliferation in hESC-CMs. CircALPK2 was abundantly expressed in hESC-CMs. Knockdown of circALPK2 significantly enhanced cell proliferation in hESC-CMs, as demonstrated by CCK-8 assays (p < 0.001) and EdU staining (p < 0.001), and accelerated the expression of cell cycle-related genes, including CCNA2(p < 0.05) and CDK1 (p < 0.01). Furthermore, circALPK2 was found to function as a sponge to inhibit miR-9 activity, while miR-9 mimics significantly boosted the proliferative capacity of hESC-CMs. Glycogen synthase kinase 3β (GSK3B), a key inhibitor of WNT signaling, was identified as a direct target of miR-9, mediating the regulation of cardiomyocyte proliferation. Importantly, circALPK2 knockdown improved the myocardial repair potential of hESC-CMs when injected into infarcted mouse hearts, as indicated by improved left ventricular ejection fraction (p < 0.01) and fractional shortening (p < 0.05).

CONCLUSIONS

Our study identifies the circALPK2/miR-9/GSK3B axis as a novel target for promoting cardiomyocyte proliferation and enhancing cardiac regeneration.

From molecules to heart regeneration: Understanding the complex and profound role of non-coding RNAs in stimulating cardiomyocyte proliferation for cardiac repair

Recent studies of noncoding genomes have shown important implications for regulating gene expression and genetic programs during development and their association with health, including cardiovascular disease. There are nearly 2,500 microRNAs (miRNAs), 12,000 long-chain non-coding RNAs (lncRNA), and nearly 4,000 circular RNAs (circles). Even though they do not code for proteins, they make up nearly 99% of the human genome. Non-coding RNA families (ncRNAs) have recently been discovered and established as novel and necessary controllers of cardiovascular risk factors and cellular processes and, therefore, have the potential to improve the diagnosis and prediction of cardiovascular disease. The increase in the prevalence of cardiovascular disease can be explained by the shortcomings of existing therapies, which focus only on the non-coding RNAs that protein codes for. On the other hand, recent studies point to the possibility of using ncRNAs in the early detection and intervention of CVD. These findings suggest that developing diagnostic tools and therapies based on miRNAs, lncRNAs, and circRNAs will potentially enhance the clinical management of patients with cardiovascular disease. Cardiovascular diseases include CH, HF, RHD, ACS, MI, AS, MF, ARR, and PAH, of which CH is the most common cardiovascular disease, followed by HF and RHD. This paper aims to elucidate the biological and clinical significance of miRNAs, increase, and circles, as well as their expression profiles and the possibility of regulating non-coding transcripts in cardiovascular diseases to improve the application of ncRNAs in diagnosis and treatment.

CircRNA-mediated regulation of cardiovascular disease

Cardiovascular diseases (CVDs) encompass a range of disorders affecting the heart and blood vessels, such as coronary heart disease, cerebrovascular disease (e.g., stroke), peripheral arterial disease, congenital heart anomalies, deep vein thrombosis, and pulmonary embolism. CVDs are often referred to as the leading cause of mortality worldwide. Recent advancements in deep sequencing have unveiled a plethora of noncoding RNA transcripts, including circular RNAs (circRNAs), which play pivotal roles in the regulation of CVDs. A decade of research has differentiated various circRNAs by their vasculoprotective or deleterious functions, revealing potential therapeutic targets. This review provides an overview of circRNAs and a comprehensive examination of CVDs, the regulatory circRNAs within the vasculature, and the burgeoning research domain dedicated to these noncoding RNAs.

The Role of Circular RNA in the Pathogenesis of Chemotherapy-Induced Cardiotoxicity in Cancer Patients: Focus on the Pathogenesis and Future Perspective

Cardiotoxicity is a serious challenge cancer patients face today. Various factors are involved in cardiotoxicity. Circular RNAs (circRNAs) are one of the effective factors in the occurrence and prevention of cardiotoxicity. circRNAs can lead to increased proliferation, apoptosis, and regeneration of cardiomyocytes by regulating the molecular pathways, as well as increasing or decreasing gene expression; some circRNAs have a dual role in cardiomyocyte regeneration or death. Identifying each of the pathways related to these processes can be effective on managing patients and preventing cardiotoxicity. In this study, an overview of the molecular pathways involved in cardiotoxicity by circRNAs and their effects on the downstream factors have been discussed.

SNRK regulates TGFβ levels in atria to control cardiac fibrosis

Atrial fibrosis is central to the pathology of heart failure (HF) and atrial fibrillation (AF). Identifying precise mechanisms underlying atrial fibrosis will provide effective strategies for clinical intervention. This study investigates a metabolic serine threonine kinase gene, sucrose non-fermenting related kinase (SNRK), that we previously reported to control cardiac metabolism and function. Conditional knockout of Snrk in mouse cardiomyocytes ( Snrk cmcKO) leads to atrial fibrosis and subsequently HF. The precise mechanism underlying cardiomyocyte SNRK-driven repression of fibrosis is not known. Here, using mouse, rat, and human tissues, we demonstrate that SNRK expression is high in atria, especially in atrial cardiomyocytes. SNRK expression correlates with lower levels of pro-fibrotic protein transforming growth factor-beta 1 (TGFβ1) in the atrial cardiomyocytes. In HL-1 adult immortalized mouse atrial cells, using siRNA approaches, we show that Snrk knockdown cells show more TGFβ1 secretion, which was also observed in heart lysates from Snrk cardiac-specific knockout mice in vivo. These effects were exacerbated upon infusion of Angiotensin II. Results from Snrk knockdown cardiomyocytes co-cultured with cardiac fibroblasts suggest that SNRK represses TGFβ1 signaling (Smad 2/3) in atrial CMs and prevents paracrine cardiac fibroblast activation (α-SMA marker). In conclusion, high SNRK expression in atria regulates cardiac homeostasis, by preventing the release of TGFβ1 secretion to block cardiac fibrosis. These studies will assist in developing heart chamber-specific fibrosis therapy for non-ischemic HF and AF.

Circular RNA in Cardiovascular Diseases: Biogenesis, Function and Application

Cardiovascular diseases pose a significant public health challenge globally, necessitating the development of effective treatments to mitigate the risk of cardiovascular diseases. Recently, circular RNAs (circRNAs), a novel class of non-coding RNAs, have been recognized for their role in cardiovascular disease. Aberrant expression of circRNAs is closely linked with changes in various cellular and pathophysiological processes within the cardiovascular system, including metabolism, proliferation, stress response, and cell death. Functionally, circRNAs serve multiple roles, such as acting as a microRNA sponge, providing scaffolds for proteins, and participating in protein translation. Owing to their unique properties, circRNAs may represent a promising biomarker for predicting disease progression and a potential target for cardiovascular drug development. This review comprehensively examines the properties, biogenesis, and potential mechanisms of circRNAs, enhancing understanding of their role in the pathophysiological processes impacting cardiovascular disease. Furthermore, the prospective clinical applications of circRNAs in the diagnosis, prognosis, and treatment of cardiovascular disease are addressed.

Non-coding RNAs as therapeutic targets and biomarkers in ischaemic heart disease

The adult heart is a complex, multicellular organ that is subjected to a series of regulatory stimuli and circuits and has poor reparative potential. Despite progress in our understanding of disease mechanisms and in the quality of health care, ischaemic heart disease remains the leading cause of death globally, owing to adverse cardiac remodelling, leading to ischaemic cardiomyopathy and heart failure. Therapeutic targets are urgently required for the protection and repair of the ischaemic heart. Moreover, personalized clinical biomarkers are necessary for clinical diagnosis, medical management and to inform the individual response to treatment. Non-coding RNAs (ncRNAs) deeply influence cardiovascular functions and contribute to communication between cells in the cardiac microenvironment and between the heart and other organs. As such, ncRNAs are candidates for translation into clinical practice. However, ncRNA biology has not yet been completely deciphered, given that classes and modes of action have emerged only in the past 5 years. In this Review, we discuss the latest discoveries from basic research on ncRNAs and highlight both the clinical value and the challenges underscoring the translation of these molecules as biomarkers and therapeutic regulators of the processes contributing to the initiation, progression and potentially the prevention or resolution of ischaemic heart disease and heart failure.

Dexmedetomidine attenuates isoflurane-induced neuroapoptosis through the miR-137/GSK-3β pathway in the developing rat hippocampus

Long-term isoflurane inhalation has been reported to induce hippocampal apoptosis in young animals, whereas dexmedetomidine (DEX) can reduce isoflurane-induced neuronal apoptosis. The neuroprotective effect of miR-137 has been reported before, however, the effect of on isoflurane triggered neuronal apoptosis, and whether miR-137 is involved in the neuroprotection of DEX remain unclear. To investigate these doubts, we established an isoflurane exposure model in postnatal day 7 (P7) Sprague‒Dawley rats and the PC12 cells, containing a control group (CON), isoflurane group (ISO), DEX group (DEX) and DEX pretreatment group (DEX + ISO). We first confirmed that DEX attenuates isoflurane-induced hippocampal apoptosis. And we found DEX increased miR-137 and attenuated GSK-3β levels in the DEX and DEX + ISO groups in the hippocampus and PC12 cells. In addition, the regulative relationship of miR-137 and GSK-3β was confirmed using the TargetScan tool and dual-luciferase reporter assay. Moreover, miR-137 overexpression inhibited GSK-3β and increased its downstream gene β-catenin, whereas knockdown of miR-137 changed the GSK-3β and β-catenin expression oppositely. Upregulation of miR-137 increased the apoptosis-related genes and decreased the anti-apoptosis gene; however, knockdown of miR-137 produced the opposite results. This study suggested that DEX attenuated isoflurane-induced neuroapoptosis by upregulating the miR-137 mediated GSK-3β/β-catenin pathway in the developing rat hippocampus.

miR-873-5p Suppression Reinvigorates Aging Mesenchymal Stem Cells and Improves Cardiac Repair after Myocardial Infarction

Aging poses obstacles to the functionality of human mesenchymal stem cells (MSCs), resulting in a notable decline in their valuable contribution to myocardial infarction (MI). MicroRNAs (miRNAs) play a pivotal role in governing MSC aging; nonetheless, the specific mechanisms remain puzzling. This research delved into the value of miR-873-5p in the management of MSC aging and investigated whether the restraint of miR-873-5p could regenerate aged MSCs (AMSCs), thereby enhancing their healing success for MI. In this study, MSCs were isolated from both young donors (referred to as YMSCs) and aged donors (referred to as AMSCs). The senescence status of these MSCs was evaluated through the application of age-related β-galactosidase (SA-β-gal) staining. Following this assessment, the MSCs, including those treated with anti-miR-873-5p-AMSCs, were then transplanted into the hearts of Sprague-Dawley rats experiencing acute myocardial infarction. Increasing miR-873-5p levels in YMSCs resulted in elevated cellular aging, whereas reducing miR-873-5p expression decreased aging in AMSCs. Mechanistically, miR-873-5p inhibited autophagy in MSCs through the AMPK signaling pathway, leading to cellular aging by suppressing the Cab39 expression. Partial alleviation of these effects was achieved by the administration of the autophagy inhibitor 3-methyladenine. Grafting of anti-miR-873-5p-AMSCs, by enhancing angiogenesis and bolstering cell survival, led to an improvement in cardiac function in the rat model, unlike the transplantation of AMSCs. miR-873-5p which serves as a pivotal element in mediating MSC aging through its regulation of the Cab39/AMPK signaling pathway. It represents an innovative target for revitalizing AMSCs and enhancing their heart-protective abilities.

Circular RNA: A new expectation for cardiovascular diseases

Circular RNA (circRNA) is a class of RNA with the 5' and 3' ends connected covalently to form a closed loop structure and characterized by high stability, conserved sequences and tissue specificity, which is caused by special reverse splicing methods. Currently, it has become a hot spot for research. With the discovery of its powerful regulatory functions and roles, the molecular mechanisms and future value of circRNA in participating in and regulating biological and pathological processes are becoming increasingly apparent. Among them is the increasing prevalence of cardiovascular diseases (CVDs). Many studies have elucidated that circRNA plays a crucial role in the development and progression of CVDs. Therefore, circRNA shows its advantages and brilliant expectations in the field of CVDs. In this review, we describe the biogenesis, bioinformatics detection and function of circRNA and discuss the role of circRNA and its effects on CVDs, including atherosclerosis, myocardial infarction, cardiac hypertrophy and heart failure, myocardial fibrosis, cardiac senescence, pulmonary hypertension, and diabetic cardiomyopathy by different mechanisms. That shows circRNA advantages and brilliant expectations in the field of CVDs.

Exploring the Multifaceted Biologically Relevant Roles of circRNAs: From Regulation, Translation to Biomarkers

CircRNAs are a category of regulatory RNAs that have garnered significant attention in the field of regulatory RNA research due to their structural stability and tissue-specific expression. Their circular configuration, formed via back-splicing, results in a covalently closed structure that exhibits greater resistance to exonucleases compared to linear RNAs. The distinctive regulation of circRNAs is closely associated with several physiological processes, as well as the advancement of pathophysiological processes in several human diseases. Despite a good understanding of the biogenesis of circular RNA, details of their biological roles are still being explored. With the steady rise in the number of investigations being carried out regarding the involvement of circRNAs in various regulatory pathways, understanding the biological and clinical relevance of circRNA-mediated regulation has become challenging. Given the vast landscape of circRNA research in the development of the heart and vasculature, we evaluated cardiovascular system research as a model to critically review the state-of-the-art understanding of the biologically relevant functions of circRNAs. We conclude the review with a discussion of the limitations of current functional studies and provide potential solutions by which these limitations can be addressed to identify and validate the meaningful and impactful functions of circRNAs in different physiological processes and diseases.

Advances in Intercellular Communication Mediated by Exosomal ncRNAs in Cardiovascular Disease

Cardiovascular diseases are a leading cause of worldwide mortality, and exosomes have recently gained attention as key mediators of intercellular communication in these diseases. Exosomes are double-layered lipid vesicles that can carry biomolecules such as miRNAs, lncRNAs, and circRNAs, and the content of exosomes is dependent on the cell they originated from. They can be involved in the pathophysiological processes of cardiovascular diseases and hold potential as diagnostic and monitoring tools. Exosomes mediate intercellular communication, stimulate or inhibit the activity of target cells, and affect myocardial hypertrophy, injury and infarction, ventricular remodeling, angiogenesis, and atherosclerosis. Exosomes can be released from various types of cells, including endothelial cells, smooth muscle cells, cardiomyocytes, fibroblasts, platelets, adipocytes, immune cells, and stem cells. In this review, we highlight the communication between different cell-derived exosomes and cardiovascular cells, with a focus on the roles of RNAs. This provides new insights for further exploring targeted therapies in the clinical management of cardiovascular diseases.

miRNA-103-3p-Hlf regulates apoptosis and autophagy by targeting hepatic leukaemia factor in heart failure

AIMS

Cardiomyocyte apoptosis is an important factor leading to the occurrence and development of heart failure (HF), which is associated with high mortality of patients with cardiovascular diseases. This study aims to investigate the underlying mechanisms of HF in terms of expression and regulation patterns using bioinformatics and experimental validation.

METHODS AND RESULTS

Two HF datasets were collected: a dataset GSE112056 downloaded from the GEO database (including mRNA and miRNA sequencing data) and another is the laboratory-owned mRNA dataset. Differential mRNAs and miRNAs in the two datasets were screened using the raw Bayesian approach method. Gene Ontology was used to perform functional enrichment analysis of the differential mRNAs and co-expression network analysis of the differential mRNAs, combined with nuclear transcription factors in the differential miRNAs and mRNAs for target gene prediction. A HF cell model was constructed using mouse cardiomyocytes (HL-1), and the role and mechanism of miRNA-103-3p-Hlf (hepatic leukaemia factor) in the process of HF was verified by cell transfection, luciferase reporter gene, WB, and qPCR. We found that Hlf gene expression was decreased in the HF model group and strongly correlated with FYCO1 (FYVE and coiled-coil domain-containing protein 1) gene, a phenomenon enriched in apoptotic autophagy-related pathways. MiR-103-3p expression was up-regulated in the HF model group, and its targeting correlation with Hlf was confirmed by luciferase activity assay. In the HL-1 cell model, miR-103-3p significantly promoted apoptosis and inhibited autophagy in HL-1 cells (all P < 0.05), and overexpression of the Hlf gene reversed this phenomenon, inhibiting apoptosis and promoting autophagy in HL-1 cells (all P < 0.05).

CONCLUSIONS

MiR-103-3p affects myocardial cells apoptosis and autophagy by targeting Hlf, playing as a potential therapeutic biomarker for HF progression.

The pathophysiological role of receptor-interacting protein kinase 3 in cardiovascular disease

Recent studies have found that receptor interacting protein kinase 3 (RIPK3) can mediate CaMK Ⅱ phosphorylation and oxidation, open mitochondrial permeability transition pore (mPTP), and induce myocardial necroptosis. The increased expression or phosphorylation of RIPK3 is one of the important markers of necroptosis; Inhibition of CaMK Ⅱ phosphorylation or oxidation significantly reduces RIPK3 mediated myocardial necroptosis; Studies have shown that necroptosis plays an important role in the occurrence and development of cardiovascular diseases; Using the selective inhibitor GSK '872 of RIPK3 can effectively inhibit the occurrence and development of cardiovascular diseases, and can reverse cardiovascular and cardiac dysfunction caused by overexpression of RIPK3. In this review, we provide a brief overview of the current knowledge on RIPK3 in mediating necroptosis, inflammatory response, and oxidative stress, and discussed the role of RIPK3 in cardiovascular diseases such as atherosclerosis, myocardial ischaemia, myocardial infarction, and heart failure.

Insights into circular RNAs : Biogenesis, function and their regulatory roles in cardiovascular disease

As a distinctive member of the noncoding RNA family, circular RNAs (circRNAs) are generated from single-stranded, covalently closed structures and are ubiquitous in mammalian cells and tissues. Due to its atypical circular architecture, it was conventionally deemed insignificant dark matter for a prolonged duration. Nevertheless, studies conducted over the last decade have demonstrated that this abundant, structurally stable and tissue-specific RNA has been increasingly relevant in diverse diseases, including cancer, neurological disorders, diabetes mellitus and cardiovascular diseases (CVDs). Therefore, regulatory pathways controlled by circRNAs are widely involved in the occurrence and pathological processes of CVDs through their function as miRNA sponges, protein sponges and protein scaffolds. To better understand the role of circRNAs and their complex regulatory networks in CVDs, we summarize current knowledge of their biogenesis and function and the latest research on circRNAs in CVDs, with the hope of paving the way for the identification of promising biomarkers and therapeutic strategies for CVDs.

The Landscape of Circular RNAs in Cardiovascular Diseases

Cardiovascular disease (CVD) remains the leading cause of mortality globally. Circular RNAs (circRNAs) have attracted extensive attention for their roles in the physiological and pathological processes of various cardiovascular diseases (CVDs). In this review, we briefly describe the current understanding of circRNA biogenesis and functions and summarize recent significant findings regarding the roles of circRNAs in CVDs. These results provide a new theoretical basis for diagnosing and treating CVDs.

Circular RNAs: Biogenesis, Biological Functions, and Roles in Myocardial Infarction

Non-coding RNAs have been excavated as important cardiac function modulators and linked to heart diseases. Significant advances have been obtained in illuminating the effects of microRNAs and long non-coding RNAs. Nevertheless, the characteristics of circular RNAs are rarely mined. Circular RNAs (circRNAs) are widely believed to participate in cardiac pathologic processes, especially in myocardial infarction. In this review, we round up the biogenesis of circRNAs, briefly describe their biological functions, and summarize the latest literature on multifarious circRNAs related to new therapies and biomarkers for myocardial infarction.

miR-103-3p Regulates the Differentiation and Autophagy of Myoblasts by Targeting MAP4

Skeletal muscle is the most abundant tissue in mammals, and myogenesis and differentiation require a series of regulatory factors such as microRNAs (miRNAs). In this study, we found that miR-103-3p was highly expressed in the skeletal muscle of mice, and the effects of miR-103-3p on skeletal muscle development were explored using myoblast C2C12 cells as a model. The results showed that miR-103-3p could significantly reduce myotube formation and restrain the differentiation of C2C12 cells. Additionally, miR-103-3p obviously prevented the production of autolysosomes and inhibited the autophagy of C2C12 cells. Moreover, bioinformatics prediction and dual-luciferase reporter assays confirmed that miR-103-3p could directly target the microtubule-associated protein 4 (MAP4) gene. The effects of MAP4 on the differentiation and autophagy of myoblasts were then elucidated. MAP4 promoted both the differentiation and autophagy of C2C12 cells, which was contrary to the role of miR-103-3p. Further research revealed that MAP4 colocalized with LC3 in C2C12 cell cytoplasm, and the immunoprecipitation assay showed that MAP4 interacted with autophagy marker LC3 to regulate the autophagy of C2C12 cells. Overall, these results indicated that miR-103-3p regulated the differentiation and autophagy of myoblasts by targeting MAP4. These findings enrich the understanding of the regulatory network of miRNAs involved in the myogenesis of skeletal muscle.

The role of β-catenin in cardiac diseases

The Wnt/β-catenin signaling pathway is a classical Wnt pathway that regulates the stability and nuclear localization of β-catenin and plays an important role in adult heart development and cardiac tissue homeostasis. In recent years, an increasing number of researchers have implicated the dysregulation of this signaling pathway in a variety of cardiac diseases, such as myocardial infarction, arrhythmias, arrhythmogenic cardiomyopathy, diabetic cardiomyopathies, and myocardial hypertrophy. The morbidity and mortality of cardiac diseases are increasing, which brings great challenges to clinical treatment and seriously affects patient health. Thus, understanding the biological roles of the Wnt/β-catenin pathway in these diseases may be essential for cardiac disease treatment and diagnosis to improve patient quality of life. In this review, we summarize current research on the roles of β-catenin in human cardiac diseases and potential inhibitors of Wnt/β-catenin, which may provide new strategies for cardiac disease therapies.

Construction of the ceRNA network in the progression of acute myocardial infarction

Acute myocardial infarction (AMI) is a common disease that induced by sudden occlusion of a coronary artery and myocardial necrosis, which causes a great medical burden worldwide. Noncoding RNAs, such as circRNA, lncRNA and miRNA, play crucial roles in the progression of cardiovascular diseases. However, the circRNA-miRNA-mRNA network in the occurrence and development of AMI needs further investigation. In this study, we downloaded three AMI datasets, including circRNA (GSE160717), miRNA (GSE24591), and mRNA (GSE66360) from GEO database. The differentially expressed candidates, and GO and KEGG functions were analyzed by RStudio, and subsequently import to PPI and Cytoscape to obtain the hub genes. By using the starbase target prediction database, we further screen the ceRNA network of circRNA-miRNA-mRNA based on the selected differentially expressed candidates. We found 46 differential expressed mRNAs, 65 miRNAs, and five circRNAs. GO functions and KEGG enrichment of the 46 mRNAs focused on immune response and functions, involving IL-17 signaling pathway, Toll-like receptor signaling pathway, cytokine-cytokine receptor interaction, TNF signaling pathway, chemokine signaling pathway, and NF-kappaB signaling pathway, which may aggravate the pathologies of AMI. PPI and Cytoscape analysis showed 10 hub genes, including TLR2, IL1B, CCL4, CCL3, CCR5, TREM1, CXCL2, NLRP3, CSF3, and CCL20. By using starbase and circinteractome databases, ceRNA network construction showed that circRNA_023461 and circRNA_400027 regulate several miRNA-mRNA axes in AMI. In summary, this study uncovered the circRNA-miRNA-mRNA network based on three AMI datasets. The differentially expressed genes, including CCL20, CCL4, CSF3, and IL1B, focus on immune functions and pathways. Furthermore, circRNA_023461 and circRNA_400027 regulate several miRNA-mRNA axes, exerting important roles in AMI progression. Our founding provides new insights into AMI and improve the therapeutic strategies for AMI.

Epigenetic regulation in myocardial infarction: Non-coding RNAs and exosomal non-coding RNAs

Myocardial infarction (MI) is one of the leading causes of deaths globally. The early diagnosis of MI lowers the rate of subsequent complications and maximizes the benefits of cardiovascular interventions. Many efforts have been made to explore new therapeutic targets for MI, and the therapeutic potential of non-coding RNAs (ncRNAs) is one good example. NcRNAs are a group of RNAs with many different subgroups, but they are not translated into proteins. MicroRNAs (miRNAs) are the most studied type of ncRNAs, and have been found to regulate several pathological processes in MI, including cardiomyocyte inflammation, apoptosis, angiogenesis, and fibrosis. These processes can also be modulated by circular RNAs and long ncRNAs via different mechanisms. However, the regulatory role of ncRNAs and their underlying mechanisms in MI are underexplored. Exosomes play a crucial role in communication between cells, and can affect both homeostasis and disease conditions. Exosomal ncRNAs have been shown to affect many biological functions. Tissue-specific changes in exosomal ncRNAs contribute to aging, tissue dysfunction, and human diseases. Here we provide a comprehensive review of recent findings on epigenetic changes in cardiovascular diseases as well as the role of ncRNAs and exosomal ncRNAs in MI, focusing on their function, diagnostic and prognostic significance.

Exosomes: mediators regulating the phenotypic transition of vascular smooth muscle cells in atherosclerosis

Cardiovascular disease is one of the leading causes of human mortality worldwide, mainly due to atherosclerosis (AS), and the phenotypic transition of vascular smooth muscle cells (VSMCs) is a key event in the development of AS. Exosomes contain a variety of specific nucleic acids and proteins that mediate intercellular communication. The role of exosomes in AS has attracted attention. This review uses the VSMC phenotypic transition in AS as the entry point, introduces the effect of exosomes on AS from different perspectives, and discusses the status quo, deficiencies, and potential future directions in this field to provide new ideas for clinical research and treatment of AS. Video Abstract.

Non-coding RNAs to regulate cardiomyocyte proliferation: A new trend in therapeutic cardiac regeneration

Cardiovascular diseases remain the leading cause of death worldwide, particularly ischemic heart disease (IHD). It is also classified as incurable given the irreversible damage it causes to cardiomyocytes. Thus, myocardial tissue rejuvenation following ischemia is one of the global primary research concerns for scientists. Interestingly, the mammalian heart thrives after an injury during the embryonic or neonatal period; however, this ability disappears with increasing age. Previous studies have found that specific non-coding (nc) RNAs play a pivotal role in this process. Hence, the review herein summarizes the research on cardiomyocyte regenerative medicine in recent years and sets forth the biological functions and mechanisms of the micro (mi)RNA, long non-coding (lnc)RNA, and circular (circ)RNA in the posttranscriptional regulation of cardiomyocytes. In addition, this review summarizes the roles of ncRNAs in specific species while enumerating potential therapeutic strategies for myocardial infarction.

Identification of potential key circular RNAs related to cognitive impairment after chronic constriction injury of the sciatic nerve

Chronic neuropathic pain is commonly accompanied by cognitive impairment. However, the underlying mechanism in the occurrence of cognitive deficits under constant nociceptive irritation remains elusive. Herein, we established a chronic neuropathic pain model by chronic constriction injury (CCI) of the unilateral sciatic nerve in rats. Behavioral tests indicated that CCI rats with long-term nociceptive threshold decline developed significant dysfunction of working memory and recognitive memory starting at 14 days and lasting for at least 21 days. Afterward, circRNA expression profiles in the hippocampus of CCI and sham rats were analyzed via high-throughput sequencing to explore the potential key factors associated with cognitive impairment induced by ongoing nociception, which showed 76 differentially expressed circRNAs, 39 upregulated and 37 downregulated, in the CCI group. These differentially expressed circRNA host genes were validated to be primarily associated with inflammation and apoptotic signaling pathways according to GO/KEGG analysis and the circRNA-miRNA-mRNA network, which was also confirmed through the analysis of neuroinflammation and neuronal apoptosis. Consequently, we assumed that enhanced neuroinflammation and neuronal apoptosis might act as potential regulators of cognitive impairment induced by chronic neuropathic pain. The identification of the regulatory mechanism would provide promising clinical biomarkers or therapeutic targets in the diagnostic prediction and intervention treatment of memory deficits under neuropathic pain conditions.

The circRNA-miRNA/RBP regulatory network in myocardial infarction

Myocardial infarction (MI) is a serious heart disease that causes high mortality rate worldwide. Noncoding RNAs are widely involved in the pathogenesis of MI. Circular RNAs (circRNAs) are recently validated to be crucial modulators of MI. CircRNAs are circularized RNAs with covalently closed loops, which make them stable under various conditions. CircRNAs can function by different mechanisms, such as serving as sponges of microRNAs (miRNAs) and RNA-binding proteins (RBPs), regulating mRNA transcription, and encoding peptides. Among these mechanisms, sponging miRNAs/RBPs is the main pathway. In this paper, we systematically review the current knowledge on the properties and action modes of circRNAs, elaborate on the roles of the circRNA-miRNA/RBP network in MI, and explore the value of circRNAs in MI diagnosis and clinical therapies. CircRNAs are widely involved in MI. CircRNAs have many advantages, such as stability, specificity, and wide distribution, which imply that circRNAs have a great potential to act as biomarkers for MI diagnosis and prognosis.

Comprehensive Analysis of circRNA-miRNA-mRNA Regulatory Network and Novel Potential Biomarkers in Acute Myocardial Infarction

Background

Circular RNA (circRNA) plays an important role in the regulation of gene expression and the occurrence of human diseases. However, studies on the role of circRNA in acute myocardial infarction (AMI) are limited. This study was performed to explore novel circRNA-related regulatory networks in AMI, aiming to better understand the molecular mechanism of circRNAs involvement in AMI and provide basis for further scientific research and clinical decision-making.

Methods

The AMI-related microarray datasets GSE160717 (circRNA), GSE31568 (miRNA), GSE61741 (miRNA), and GSE24519 (mRNA) were obtained from the Gene Expression Omnibus (GEO) database. After differential expression analysis, the regulatory relationships between these DERNAs were identified by online databases circBank, circInteractome, miRDB, miRWalk, Targetscan, and then two circRNA-miRNA-mRNA regulatory networks were constructed. Differentially expressed genes (DEGs) in this network were selected followed by enrichment analysis and protein–protein interaction (PPI) analysis. Hub genes were identified using Cytohubba plug-in of Cytoscape software. Hub genes and hub gene-related miRNAs were used for receiver operating characteristic curve (ROC) analysis to identify potential biomarkers. The relative expression levels of these biomarkers were further assessed by GSE31568 (miRNA) and GSE66360 (mRNA). Finally, on the basis of the above analysis, myocardial hypoxia model was constructed to verify the expression of Hub genes and related circRNAs.

Results

A total of 83 DEcircRNAs, 109 CoDEmiRNAs and 1204 DEGs were significantly differentially expressed in these datasets. The up-regulated circRNAs and down-regulated circRNAs were used to construct a circRNA-miRNA-mRNA regulatory network respectively. These circRNA-related DEGs were mainly enriched in the terms of “FOXO signaling pathway,” “T cell receptor signaling pathway,” “MAPK signaling pathway,” “Insulin resistance,” “cAMP signaling pathway,” and “mTOR signaling pathway.” The top 10 hub genes ATP2B2, KCNA1, GRIN2A, SCN2B, GPM6A, CACNA1E, HDAC2, SRSF1, ANK2, and HNRNPA2B1 were identified from the PPI network. Hub genes GPM6A, SRSF1, ANK2 and hub gene-related circRNAs hsa_circ_0023461, hsa_circ_0004561, hsa_circ_0001147, hsa_circ_0004771, hsa_circ_0061276, and hsa_circ_0045519 were identified as potential biomarkers in AMI.

Conclusion

In this study, the potential circRNAs associated with AMI were identified and two circRNA-miRNA-mRNA regulatory networks were constructed. This study explored the mechanism of circRNA involvement in AMI and provided new clues for the selection of new diagnostic markers and therapeutic targets for AMI.

Stem Cell-derived Exosomal MicroRNA as Therapy for Vascular Age-related Diseases

Vascular age-related diseases describe a group of age-related chronic diseases that result in a considerable healthcare burden to society. Vascular aging includes structural changes and dysfunctions of endothelial cells (ECs) and smooth muscle cells (SMCs) in blood vessels. Compared with conventional treatment for vascular age-related diseases, stem cell (SC) therapy elicits better anti-aging effects viathe inhibition/delay ECs and SMCs from entering senescence. Exosomal noncoding RNA (ncRNAs) in vascular aging and stem cell-derived exosomal microRNAs (SCEV-miRNAs), especially in mesenchymal stem cells, have an important role in the development of age-related diseases. This review summarizes SCEV-miRNAs of diverse origins that may play a vital role in treating subclinical and clinical stages of vascular age-related disorders. We further explored possible age-related pathways and molecular targets of SCEV-miRNA, which are associated with dysfunctions of ECs and SMCs in the senescent stage. Moreover, the perspectives and difficulties of SCEV-miRNA clinical translation are discussed. This review aims to provide greater understanding of the biology of vascular aging and to identify critical therapeutic targets for SCEV-miRNAs. Though still in its infancy, the potential value of SCEV-miRNAs for vascular age-related diseases is clear.

CPE Regulates Proliferation and Apoptosis of Primary Myocardial Cells Mediated by Ischemia and Hypoxia Injury

Objective

To observe the effect of carboxypeptidase E (CPE) on the ischemia and hypoxia (I/H) injury of primary cardiomyocytes.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) technology was used to detect the expression of CPE in sham and myocardial infarction (MI) rat heart tissue, and the plasmid was transferred into primary cardiomyocytes by transfection technology. The apoptosis rate of cardiomyocytes was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, Annexin V-PI staining, and Cell Counting Kit-8 (CCK-8) assay. In addition, Caspase kit and qRT-PCR technology were used to detect the expression of apoptosis-related factors. The cell proliferation was detected by 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry, and qRT-PCR technology. In addition, Western blotting (WB) and qRT-PCR techniques were used to detect the Wnt/β-catenin pathway.

Results

First, we found that the expression of CPE in the marginal zone of MI was obviously reduced. Overexpression of CPE in primary cardiomyocytes can effectively inhibit ischemia/hypoxia (I/H)-induced apoptosis and decreased cell activity. In addition, CPE can promote cell proliferation and relieve the inhibitory effect of I/H on cardiomyocytes. At the same time, CPE can promote the expression of β-catenin and c-myc.

Conclusion

Overexpression of CPE in primary cardiomyocytes can effectively alleviate the decreased cell activity, increased apoptosis, and decreased proliferation caused by I/H and regulated by Wnt/β-catenin pathway.

NDRG4 Alleviates Myocardial Infarction-Induced Apoptosis through the JAK2/STAT3 Pathway

OBJECTIVE

At present, studies have confirmed that NDRG4 is specifically expressed in the heart, while its effect on the heart is still unclear. This study is to explore the effect of NDRG4 on cardiomyocyte apoptosis caused by acute myocardial infarction (AMI).

METHODS

Twenty SD rats were randomly divided into Sham (left anterior descent of heart without ligation) and AMI groups. In this study, coronary artery ligation was used to establish an AMI model, and the AMI model was verified by auxiliary examination and pathological examination. Besides, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB) was used to detect the expression level of Bax and Bcl-2 in heart tissues, and NDRG mRNA levels in tissues were also detected. qRT-PCR technology was used to verify the transfection efficiency of NDRG4 in H9C2 cells, and the change of apoptosis level of H9C2 cells was detected by Cell Counting Kit-8 (CCK-8) assay and TUNEL staining; besides, the expression level of apoptosis-related factors was detected by WB and qRT-PCR technology. Simultaneously with the modeling of rats, we injected adenovirus (Ad) into the heart tissue and examined the structural and functional changes of the rat heart. Then, WB technology was used to detect the expression level of the JAK2/STAT3 signaling pathway.

RESULTS

The heart function and heart structure of rats in the MI group were dramatically worse, and the expression level of NDRG4 was also dramatically reduced. The overexpression of NDRG4 in H9C2 cells can effectively inhibit the ischemia/hypoxia- (I/H-) induced decrease in cell viability and increase in apoptosis rate and inhibit the increase in Bax/Bcl-2 ratio. Moreover, overexpression of NDRG4 in heart tissue can effectively improve the cardiac function and structural destruction caused by MI. In addition, NDRG4 can inhibit JAK2/STAT3 pathway activation.

CONCLUSION

The expression of NDRG4 in the MI tissue of rats was suppressed, while overexpression of NDRG4 by injection of Ad can obviously protect the rat heart. Furthermore, overexpression of NDRG4 in H9C2 cells can effectively inhibit the I/H-induced decrease in cell viability and increase in apoptosis rate, and this may be related to the inhibition of the JAK2/STAT3 signaling pathway.

The Regulation Mechanisms and Clinical Application of MicroRNAs in Myocardial Infarction: A Review of the Recent 5 Years

Myocardial infarction (MI) is the most frequent end-point of cardiovascular pathology, leading to higher mortality worldwide. Due to the particularity of the heart tissue, patients who experience ischemic infarction of the heart, still suffered irreversible damage to the heart even if the vascular reflow by treatment, and severe ones can lead to heart failure or even death. In recent years, several studies have shown that microRNAs (miRNAs), playing a regulatory role in damaged hearts, bring light for patients to alleviate MI. In this review, we summarized the effect of miRNAs on MI with some mechanisms, such as apoptosis, autophagy, proliferation, inflammatory; the regulation of miRNAs on cardiac structural changes after MI, including angiogenesis, myocardial remodeling, fibrosis; the application of miRNAs in stem cell therapy and clinical diagnosis; other non-coding RNAs related to miRNAs in MI during the past 5 years.

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

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

Emerging roles of circRNAs in the pathological process of myocardial infarction

Myocardial infarction (MI) is defined as cardiomyocyte death in a clinical context consistent with ischemic insult. MI remains one of the leading causes of morbidity and mortality worldwide. Although there are a number of effective clinical methods for the diagnosis and treatment of MI, further investigation of novel biomarkers and molecular therapeutic targets is required. Circular RNAs (circRNAs), novel non-coding RNAs, have been reported to function mainly by acting as microRNA (miRNA) sponges or binding to RNA-binding proteins (RBPs). The circRNA-miRNA-mRNA (protein) regulatory pathway regulates gene expression and affects the pathological mechanisms of various diseases. Undoubtedly, a more comprehensive understanding of the relationship between MI and circRNA will lay the foundation for the development of circRNA-based diagnostic and therapeutic strategies for MI. Therefore, this review summarizes the pathophysiological process of MI and various approaches to measure circRNA levels in MI patients, tissues, and cells; highlights the significance of circRNAs in the regulation MI pathogenesis and development; and provides potential clinical insight for the diagnosis, prognosis, and treatment of MI.

Knockdown of hsa_circ_0000729 Inhibits the Tumorigenesis of Non-Small Cell Lung Cancer Through Mediation of miR-1281/FOXO3 Axis

Background

Non-small cell lung cancer (NSCLC) is a subtype of lung cancer which seriously threatens the health of people. Circular RNAs (CircRNAs) are endogenous RNAs which have stable closed structure; they are known to be involved in tumorigenesis of NSCLC. Meanwhile, hsa_circ_0000729 was reported to be upregulated in NSCLC. Nevertheless, the function of hsa_circ_0000729 in NSCLC remains unclear.

Methods

Western blot and RT-qPCR were performed to investigate protein and mRNA levels, respectively. CCK-8 assay was performed to test the cell viability and cell death was investigated by flow cytometry. NSCLC cell pyroptosis was observed by electron microscope. In addition, the migration and invasion of NSCLC cells were detected by wound healing and transwell assay. The relation among hsa_circ_0000729, miR-1281 and FOXO3 was explored by dual luciferase reporter assay and RNA pull-down.

Results

Hsa_circ_0000729 was found to be upregulated in NSCLC cells, and hsa_circ_0000729 knockdown obviously suppressed the proliferation of NSCLC cells through inducing pyroptosis. In addition, silencing of hsa_circ_0000729 notably inhibited the invasion and migration of NSCLC cells. Meanwhile, hsa_circ_0000729 could bind with miR-1281, and FOXO3 was directly targeted by miR-1281. Moreover, the anti-tumor effect of hsa_circ_0000729 siRNAs on NSCLC was markedly reversed by miR-1281 antagomir. Furthermore, silencing of hsa_circ_0000729 inhibited the tumor growth of NSCLC in vivo.

Conclusion

Knockdown of hsa_circ_0000729 inhibits the tumorigenesis of NSCLC through mediation of miR-1281/FOXO3 axis. Thus, hsa_circ_0000729 might be served as a crucial mediator in NSCLC.

Recent Advances in Gene Therapy for Cardiac Tissue Regeneration

Cardiovascular diseases (CVDs) are responsible for enormous socio-economic impact and the highest mortality globally. The standard of care for CVDs, which includes medications and surgical interventions, in most cases, can delay but not prevent the progression of disease. Gene therapy has been considered as a potential therapy to improve the outcomes of CVDs as it targets the molecular mechanisms implicated in heart failure. Cardiac reprogramming, therapeutic angiogenesis using growth factors, antioxidant, and anti-apoptotic therapies are the modalities of cardiac gene therapy that have led to promising results in preclinical studies. Despite the benefits observed in animal studies, the attempts to translate them to humans have been inconsistent so far. Low concentration of the gene product at the target site, incomplete understanding of the molecular pathways of the disease, selected gene delivery method, difference between animal models and humans among others are probable causes of the inconsistent results in clinics. In this review, we discuss the most recent applications of the aforementioned gene therapy strategies to improve cardiac tissue regeneration in preclinical and clinical studies as well as the challenges associated with them. In addition, we consider ongoing gene therapy clinical trials focused on cardiac regeneration in CVDs.

Role of non-coding RNAs as biomarkers of deleterious cardiovascular effects in sepsis

The mechanisms occurring during sepsis that produce an increased risk of cardiovascular (CV) disease (CVD) are poorly understood. Even less information exists regarding CV dysfunction as a complication of sepsis, particularly for sepsis-induced cardiomyopathy. However, recent research has demonstrated that non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, play a crucial role in genetic reprogramming, gene regulation, and inflammation during the development of CVD. Here we describe experimental findings showing the importance of non-coding RNAs mediating relevant mechanisms underlying CV dysfunction after sepsis, so contributing to sepsis-induced cardiomyopathy. Importantly, non-coding RNAs are critical novel regulators of CVD risk factors. Thus, they are potential candidates to improve diagnostics and prognosis of sepsis-induced cardiomyopathy and other CVD events occurring after sepsis and set the basis to design novel therapeutic strategies.