Inhibition of Exo-miR-19a-3p derived from cardiomyocytes promotes angiogenesis and improves heart function in mice with myocardial infarction via targeting HIF-1α

microRNAs: critical targets for treating rheumatoid arthritis angiogenesis

Vascular neogenesis, an early event in the development of rheumatoid arthritis (RA) inflammation, is critical for the formation of synovial vascular networks and plays a key role in the progression and persistence of chronic RA inflammation. microRNAs (miRNAs), a class of single-stranded, non-coding RNAs with approximately 21-23 nucleotides in length, regulate gene expression by binding to the 3' untranslated region (3'-UTR) of specific mRNAs. Increasing evidence suggests that miRNAs are differently expressed in diseases associated with vascular neogenesis and play a crucial role in disease-related vascular neogenesis. However, current studies are not sufficient and further experimental studies are needed to validate and establish the relationship between miRNAs and diseases associated with vascular neogenesis, and to determine the specific role of miRNAs in vascular development pathways. To better treat vascular neogenesis in diseases such as RA, we need additional studies on the role of miRNAs and their target genes in vascular development, and to provide more strategic references. In addition, future studies can use modern biotechnological methods such as proteomics and transcriptomics to investigate the expression and regulatory mechanisms of miRNAs, providing a more comprehensive and in-depth research basis for the treatment of related diseases such as RA.

Small extracellular vesicles associated miRNA in myocardial fibrosis

Myocardial fibrosis involves the loss of cardiomyocytes, myocardial fibroblast proliferation, and a reduction in angiogenesis, ultimately leading to heart failure, Given its significant implications, it is crucial to explore novel therapies for myocardial fibrosis. Recently one emerging avenue has been the use of small extracellular vesicles (sEV)-carried miRNA. In this review, we summarize the regulatory role of sEV-carried miRNA in myocardial fibrosis. We explored not only the potential diagnostic value of circulating miRNA as biomarkers for heart disease but also the therapeutic implications of sEV-carried miRNA derived from various cellular sources and applications of modified sEV. This exploration is paramount for researchers striving to develop innovative, cell-free therapies as potential drug candidates for the management of myocardial fibrosis.

Regulation mechanism of microRNAs in cardiac cells-derived exosomes in cell crosstalk

The heart is a multicellular system, and the intercellular crosstalk mechanism is very important for the growth and development of the heart and even the organs, tissues, and cells at a distance. As a kind of extracellular vesicle, exosomes are released by different types of cells and can carry specific genetic material, endosomal proteins, cytokines, etc., which are the main material basis for mediating cell crosstalk mechanism. Among them, microRNA carried by cardiac cells-derived exosomes have highly conserved sequences and play a key role in regulating the function of organs, tissues, and cells related to cardiovascular diseases and their complications and comorbidities, which have attracted extensive attention in the medical community in recent years. Following up on the latest research progress at home and abroad, this review systematically summarized the regulatory role of microRNA from cardiac cells-derived exosomes in various cell crosstalk, including not only cardiac cells (including cardiomyocytes, fibroblasts, myofibroblast, cardiac progenitor cells, cardiac microvascular endothelial cells, cardiosphere-derived cells, etc.) but also tumor cells, bone marrow progenitor cells, and other tissue cells, in order to provide a reference for the prevention and treatment of cardiovascular diseases and their complications and comorbidities.

Regulation of the HIF switch in human endothelial and cancer cells

Hypoxia-inducible factors (HIFs) are transcription factors that reprogram the transcriptome for cells to survive hypoxic insults and oxidative stress. They are important during embryonic development and reprogram the cells to utilize glycolysis when the oxygen levels are extremely low. This metabolic change facilitates normal cell survival as well as cancer cell survival. The key feature in survival is the transition between acute hypoxia and chronic hypoxia, and this is regulated by the transition between HIF-1 expression and HIF-2/HIF-3 expression. This transition is observed in many human cancers and endothelial cells and referred to as the HIF Switch. Here we discuss the mechanisms involved in the HIF Switch in human endothelial and cancer cells which include mRNA and protein levels of the alpha chains of the HIFs. A major continuing effort in this field is directed towards determining the differences between normal and tumor cell utilization of this important pathway, and how this could lead to potential therapeutic approaches.

Mesenchymal Stem Cell-Derived Exosomes and Their MicroRNAs in Heart Repair and Regeneration

Mesenchymal stem cells (MSCs) can be differentiated into cardiac, endothelial, and smooth muscle cells. Therefore, MSC-based therapeutic approaches have the potential to deal with the aftermaths of cardiac diseases. However, transplanted stem cells rarely survive in damaged myocardium, proposing that paracrine factors other than trans-differentiation may involve in heart regeneration. Apart from cytokines/growth factors, MSCs secret small, single-membrane organelles named exosomes. The MSC-secreted exosomes are enriched in lipids, proteins, nucleic acids, and microRNA (miRNA). There has been an increasing amount of data that confirmed that MSC-derived exosomes and their active molecule microRNA (miRNAs) regulate signaling pathways involved in heart repair/regeneration. In this review, we systematically present an overview of MSCs, their cardiac differentiation, and the role of MSC-derived exosomes and exosomal miRNAs in heart regeneration. In addition, biological functions regulated by MSC-derived exosomes and exosomal-derived miRNAs in the process of heart regeneration are reviewed.

Identification of Potential Crucial Biomarkers in STEMI Through Integrated Bioinformatic Analysis

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) is one of the leading causes of fatal cardiovascular diseases, which have been the prime cause of mortality worldwide. Diagnosis in the early phase would benefit clinical intervention and prognosis, but the exploration of the biomarkers of STEMI is still lacking.

OBJECTIVES

In this study, we conducted a bioinformatics analysis to identify potential crucial biomarkers in the progress of STEMI.

METHODS

We obtained GSE59867 for STEMI and stable coronary artery disease (SCAD) patients. Differentially expressed genes (DEGs) were screened with the threshold of |log2fold change| > 0.5 and p <0.05. Based on these genes, we conducted enrichment analysis to explore the potential relevance between genes and to screen hub genes. Subsequently, hub genes were analyzed to detect related miRNAs and DAVID to detect transcription factors for further analysis. Finally, GSE62646 was utilized to assess DEGs specificity, with genes demonstrating AUC results exceeding 75%, indicating their potential as candidate biomarkers.

RESULTS

133 DEGs between SCAD and STEMI were obtained. Then, the PPI network of DEGs was constructed using String and Cytoscape, and further analysis determined hub genes and 6 molecular complexes. Functional enrichment analysis of the DEGs suggests that pathways related to inflammation, metabolism, and immunity play a pivotal role in the progression from SCAD to STEMI. Besides, related-miRNAs were predicted, has-miR-124, has-miR-130a/b, and has-miR-301a/b regulated the expression of the largest number of genes. Meanwhile, Transcription factors analysis indicate that EVI1, AML1, GATA1, and PPARG are the most enriched gene. Finally, ROC curves demonstrate that MS4A3, KLRC4, KLRD1, AQP9, and CD14 exhibit both high sensitivity and specificity in predicting STEMI.

CONCLUSIONS

This study revealed that immunity, metabolism, and inflammation are involved in the development of STEMI derived from SCAD, and 6 genes, including MS4A3, KLRC4, KLRD1, AQP9, CD14, and CCR1, could be employed as candidate biomarkers to STEMI.

Unraveling the Signaling Dynamics of Small Extracellular Vesicles in Cardiac Diseases

Effective intercellular communication is essential for cellular and tissue balance maintenance and response to challenges. Cellular communication methods involve direct cell contact or the release of biological molecules to cover short and long distances. However, a recent discovery in this communication network is the involvement of extracellular vesicles that host biological contents such as proteins, nucleic acids, and lipids, influencing neighboring cells. These extracellular vesicles are found in body fluids; thus, they are considered as potential disease biomarkers. Cardiovascular diseases are significant contributors to global morbidity and mortality, encompassing conditions such as ischemic heart disease, cardiomyopathies, electrical heart diseases, and heart failure. Recent studies reveal the release of extracellular vesicles by cardiovascular cells, influencing normal cardiac function and structure. However, under pathological conditions, extracellular vesicles composition changes, contributing to the development of cardiovascular diseases. Investigating the loading of molecular cargo in these extracellular vesicles is essential for understanding their role in disease development. This review consolidates the latest insights into the role of extracellular vesicles in diagnosis and prognosis of cardiovascular diseases, exploring the potential applications of extracellular vesicles in personalized therapies, shedding light on the evolving landscape of cardiovascular medicine.

Advances in the study of exosomes in cardiovascular diseases

BACKGROUND

Cardiovascular disease (CVD) has been the leading cause of death worldwide for many years. In recent years, exosomes have gained extensive attention in the cardiovascular system due to their excellent biocompatibility. Studies have extensively researched miRNAs in exosomes and found that they play critical roles in various physiological and pathological processes in the cardiovascular system. These processes include promoting or inhibiting inflammatory responses, promoting angiogenesis, participating in cell proliferation and migration, and promoting pathological progression such as fibrosis.

AIM OF REVIEW

This systematic review examines the role of exosomes in various cardiovascular diseases such as atherosclerosis, myocardial infarction, ischemia-reperfusion injury, heart failure and cardiomyopathy. It also presents the latest treatment and prevention methods utilizing exosomes. The study aims to provide new insights and approaches for preventing and treating cardiovascular diseases by exploring the relationship between exosomes and these conditions. Furthermore, the review emphasizes the potential clinical use of exosomes as biomarkers for diagnosing cardiovascular diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Exosomes are nanoscale vesicles surrounded by lipid bilayers that are secreted by most cells in the body. They are heterogeneous, varying in size and composition, with a diameter typically ranging from 40 to 160 nm. Exosomes serve as a means of information communication between cells, carrying various biologically active substances, including lipids, proteins, and small RNAs such as miRNAs and lncRNAs. As a result, they participate in both physiological and pathological processes within the body.

Exosomes and the cardiovascular system: role in cardiovascular health and disease

Exosomes, which are membrane-bound extracellular vesicles (EVs), are generated in the endosomal compartment of almost all eukaryotic cells. They are formed upon the fusion of multivesicular bodies and the plasma membrane and carry proteins, nucleic acids, lipids and other cellular constituents from their parent cells. Multiple factors influence their production including cell stress and injury, humoral factors, circulating toxins, and oxidative stress. They play an important role in intercellular communication, through their ability to transfer their cargo (proteins, lipids, RNAs) from one cell to another. Exosomes have been implicated in the pathophysiology of various diseases including cardiovascular disease (CVD), cancer, kidney disease, and inflammatory conditions. In addition, circulating exosomes may act as biomarkers for diagnostic and prognostic strategies for several pathological processes. In particular exosome-containing miRNAs have been suggested as biomarkers for the diagnosis and prognosis of myocardial injury, stroke and endothelial dysfunction. They may also have therapeutic potential, acting as vectors to deliver therapies in a targeted manner, such as the delivery of protective miRNAs. Transfection techniques are in development to load exosomes with desired cargo, such as proteins or miRNAs, to achieve up-regulation in the host cell or tissue. These advances in the field have the potential to assist in the detection and monitoring progress of a disease in patients during its early clinical stages, as well as targeted drug delivery.

Engineering Extracellular Matrix-Bound Nanovesicles Secreted by Three-Dimensional Human Mesenchymal Stem Cells

Extracellular matrix (ECM) in the human tissue contains vesicles, which are defined as matrix-bound nanovesicles (MBVs). MBVs serve as one of the functional components in ECM, recapitulating part of the regulatory roles and in vivo microenvironment. In this study, extracellular vesicles from culture supernatants (SuEVs) and MBVs are isolated from the conditioned medium or ECM, respectively, of 3D human mesenchymal stem cells. Nanoparticle tracking analysis shows that MBVs are smaller than SuEVs (100-150 nm). Transmission electron microscopy captures the typical cup shape morphology for both SuEVs and MBVs. Western blot reveals that MBVs have low detection of some SuEV markers such as syntenin-1. miRNA analysis of MBVs shows that 3D microenvironment enhances the expression of miRNAs such as miR-19a and miR-21. In vitro functional analysis shows that MBVs can facilitate human pluripotent stem cell-derived forebrain organoid recovery after starvation and promote high passage fibroblast proliferation. In macrophage polarization, 2D MBVs tend to suppress the pro-inflammatory cytokine IL-12β, while 3D MBVs tend to enhance the anti-inflammatory cytokine IL-10. This study has the significance in advancing the understanding of the bio-interface of nanovesicles with human tissue and the design of cell-free therapy for treating neurological disorders such as ischemic stroke.

Advances in the study of exosomes derived from mesenchymal stem cells and cardiac cells for the treatment of myocardial infarction

Acute myocardial infarction has long been the leading cause of death in coronary heart disease, which is characterized by irreversible cardiomyocyte death and restricted blood supply. Conventional reperfusion therapy can further aggravate myocardial injury. Stem cell therapy, especially with mesenchymal stem cells (MSCs), has emerged as a promising approach to promote cardiac repair and improve cardiac function. MSCs may induce these effects by secreting exosomes containing therapeutically active RNA, proteins and lipids. Notably, normal cardiac function depends on intracardiac paracrine signaling via exosomes, and exosomes secreted by cardiac cells can partially reflect changes in the heart during disease, so analyzing these vesicles may provide valuable insights into the pathology of myocardial infarction as well as guide the development of new treatments. The present review examines how exosomes produced by MSCs and cardiac cells may influence injury after myocardial infarction and serve as therapies against such injury. Video Abstract.

New Insights into the Reparative Angiogenesis after Myocardial Infarction

Myocardial infarction (MI) causes massive loss of cardiac myocytes and injury to the coronary microcirculation, overwhelming the limited capacity of cardiac regeneration. Cardiac repair after MI is finely organized by complex series of procedures involving a robust angiogenic response that begins in the peri-infarcted border area of the infarcted heart, concluding with fibroblast proliferation and scar formation. Efficient neovascularization after MI limits hypertrophied myocytes and scar extent by the reduction in collagen deposition and sustains the improvement in cardiac function. Compelling evidence from animal models and classical in vitro angiogenic approaches demonstrate that a plethora of well-orchestrated signaling pathways involving Notch, Wnt, PI3K, and the modulation of intracellular Ca2+ concentration through ion channels, regulate angiogenesis from existing endothelial cells (ECs) and endothelial progenitor cells (EPCs) in the infarcted heart. Moreover, cardiac repair after MI involves cell-to-cell communication by paracrine/autocrine signals, mainly through the delivery of extracellular vesicles hosting pro-angiogenic proteins and non-coding RNAs, as microRNAs (miRNAs). This review highlights some general insights into signaling pathways activated under MI, focusing on the role of Ca2+ influx, Notch activated pathway, and miRNAs in EC activation and angiogenesis after MI.

P38 MAPK activated ADAM17 mediates ACE2 shedding and promotes cardiac remodeling and heart failure after myocardial infarction

BACKGROUND

Heart failure (HF) after myocardial infarction (MI) is a prevalent disease with a poor prognosis. Relieving pathological cardiac remodeling and preserving cardiac function is a critical link in the treatment of post-MI HF. Thus, more new therapeutic targets are urgently needed. The expression of ADAM17 is increased in patients with acute MI, but its functional role in post-MI HF remains unclear.

METHODS

To address this question, we examined the effects of ADAM17 on the severity and prognosis of HF within 1 year of MI in 152 MI patients with or without HF. In mechanistic studies, the effects of ADAM17 on ventricular remodeling and systolic function were extensively assessed at the tissue and cellular levels by establishing animal model of post-MI HF and in vitro hypoxic cell model.

RESULTS

High levels of ADAM17 predicted a higher incidence of post-MI HF, poorer cardiac function and higher mortality. Animal studies demonstrated that ADAM17 promoted the occurrence of post-MI HF, as indicated by increased infarct size, cardiomyocyte hypertrophy, myocardial interstitial collagen deposition and cardiac failure. ADAM17 knock down significantly improved pathological cardiac remodeling and cardiac function in mice with MI. Mechanistically, activated ADAM17 inhibited the cardioprotective effects of ACE2 by promoting hydrolytic shedding of the transmembrane protein ACE2 in cardiomyocytes, which subsequently mediated the occurrence of cardiac remodeling and the progression of heart failure. Moreover, the activation of ADAM17 in hypoxic cardiomyocytes was dependent on p38 MAPK phosphorylation at threonine 735.

CONCLUSIONS

These data highlight a novel and important mechanism for ADAM17 to cause post-MI HF, which will hopefully be a new potential target for early prediction or intervention of post-MI HF. Video abstract.

Exosomes in Cardiovascular Disease: From Mechanism to Therapeutic Target

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. In recent decades, clinical research has made significant advances, resulting in improved survival and recovery rates for patients with CVD. Despite this progress, there is substantial residual CVD risk and an unmet need for better treatment. The complex and multifaceted pathophysiological mechanisms underlying the development of CVD pose a challenge for researchers seeking effective therapeutic interventions. Consequently, exosomes have emerged as a new focus for CVD research because their role as intercellular communicators gives them the potential to act as noninvasive diagnostic biomarkers and therapeutic nanocarriers. In the heart and vasculature, cell types such as cardiomyocytes, endothelial cells, vascular smooth muscle, cardiac fibroblasts, inflammatory cells, and resident stem cells are involved in cardiac homeostasis via the release of exosomes. Exosomes encapsulate cell-type specific miRNAs, and this miRNA content fluctuates in response to the pathophysiological setting of the heart, indicating that the pathways affected by these differentially expressed miRNAs may be targets for new treatments. This review discusses a number of miRNAs and the evidence that supports their clinical relevance in CVD. The latest technologies in applying exosomal vesicles as cargo delivery vehicles for gene therapy, tissue regeneration, and cell repair are described.

Exosomes derived from M1 macrophages inhibit the proliferation of the A549 and H1299 lung cancer cell lines via the miRNA-let-7b-5p-GNG5 axis

Background

Almost all cells are capable of secreting exosomes (Exos) for intercellular communication and regulation. Therefore, Exos can be used as a natural therapeutic platform to regulate genes or deliver drugs to treat diseases. M1 macrophages inhibit tumor growth by releasing pro-inflammatory factors. This study explored the applicability of M1 macrophage exosomes (M1-Exos) as gene carriers and the effects on GNG5 protein, and further examined whether macrophage repolarization could inhibit tumor activity.

Methods

M0 macrophages were polarized toward M1 using vitexin. Exos were obtained from M1 macrophages by ultra-centrifugation. The transwell non-contact co-culture system was used to co-culture M1 macrophages with HLF-α human lung epithelial cells or A549 or H1299 lung cancer cells. MTT, scratch, and transwell assays were used to detect the cell viability, migration, and invasion ability of cells in the four groups. Flow cytometry was used to detect the apoptosis rate of each group, and western blot (WB) analysis was performed to detect the change in the expression of proliferation- and apoptosis-related proteins. We screened the differentially expressed microRNAs using quantitative polymerase chain reaction technology. Luciferase reporter analysis was performed to explore the interaction between miRNA and protein. We used Xenografted A549 tumors in nude mice to study the effect of M1-Exos on tumor cell growth in vivo.

Results

The results showed that, under the M1 macrophage co-culture system, lung cancer cell viability, invasion, and migration ability decreased, and the number of apoptotic cells increased, will all indicators being statistically significant (P < 0.05). The expression levels of PCNA, KI67, and Bcl-2 decreased significantly, but that of Bax increased (P < 0.05). Exosomes can have the same effect on tumor cells as M1 macrophages. Exosomes can transport miR-let-7b-5p to tumor cells, and miR-let-7b-5p can inhibit tumor cell proliferation and promote tumor cell apoptosis by regulating the GNG5 protein level.

Conclusions

M1-Exos inhibit the proliferation, invasion, and metastasis of lung cancer cells through miRNA-let-7b-5p and GNG5 signaling pathways and inhibit the anti-apoptotic ability of lung cancer cells.

Extracellular Non-Coding RNAs in Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain the world's leading cause of death despite the best available healthcare and therapy. Emerging as a key mediator of intercellular and inter-organ communication in CVD pathogenesis, extracellular vesicles (EVs) are a heterogeneous group of membrane-enclosed nano-sized vesicles released by virtually all cells, of which their RNA cargo, especially non-coding RNAs (ncRNA), has been increasingly recognized as a promising diagnostic and therapeutic target. Recent evidence shows that ncRNAs, such as small ncRNAs, circular RNAs, and long ncRNAs, can be selectively sorted into EVs or other non-vesicular carriers and modulate various biological processes in recipient cells. In this review, we summarize recent advances in the literature regarding the origin, extracellular carrier, and functional mechanisms of extracellular ncRNAs with a focus on small ncRNAs, circular RNAs, and long ncRNAs. The pathophysiological roles of extracellular ncRNAs in various CVDs, including atherosclerosis, ischemic heart diseases, hypertension, cardiac hypertrophy, and heart failure, are extensively discussed. We also provide an update on recent developments and challenges in using extracellular ncRNAs as biomarkers or therapeutical targets in these CVDs.

Updated Methods of Extracellular Vesicles Isolation

Extracellular vesicles (EVs) are considered as cargo and mediate intercellular communication. As natural biological nanoparticles, EVs can be secreted by almost all kinds of cells and exist in biofluids such as milk, urine, blood, etc. In the past decades, several methods have been utilized to isolate EVs from cell culture medium, biofluids, and tissues. Here in this chapter, we summarized conventional and novel methods and fundamental procedures of EVs extraction and purification from different biofluids (plasma, urine, milk, and saliva) and tissues (brain, intestinal tissue, muscles, and heart). The present section also discusses how to choose appropriate methods to extract EVs from tissues based on downstream analysis. This chapter will expand the horizons of EVs isolation and purification from different mediums.

Analysis of the Research Hotspot of Exosomes in Cardiovascular Disease: A Bibliometric-based Literature Review

OBJECTIVE

To investigate the current status and development trend of research on exosomes in cardiovascular disease (CVD) using bibliometric analysis and to elucidate trending research topics.

METHODS

Research articles on exosomes in CVD published up to April 2022 were retrieved from the Web of Science database. Data were organized using Microsoft Office Excel 2019. CiteSpace 6.1 and VOSviewer 1.6.18 were used for bibliometric analysis and result visualization.

RESULTS

Overall, 256 original research publications containing 190 fundamental research publications and 66 clinical research publications were included. "Extracellular vesicle" was the most frequent research keyword, followed by "microrna," "apoptosis," and "angiogenesis." Most publications were from China (187, 73.05%), followed by the United States (57, 22.27%), the United Kingdom (7, 2.73%), and Japan (7, 2.73%). A systematic review of the publications revealed that myocardial infarction and stroke were the most popular topics and that exosomes and their contents, such as microRNAs (miRNAs), play positive roles in neuroprotection, inhibition of autophagy and apoptosis, promotion of angiogenesis, and protection of cardiomyocytes.

CONCLUSION

Research on exosomes in CVD has attracted considerable attention, with China having the most published studies. Fundamental research has focused on CVD pathogenesis; exosomes regulate the progression of CVD through biological processes, such as the inflammatory response, autophagy, and apoptosis. Clinical research has focused on biomarkers for CVD; studies on using miRNAs in exosomes as disease markers for diagnosis could become a future trend.

Exosomes and Exosomal Cargos: A Promising World for Ventricular Remodeling Following Myocardial Infarction

Exosomes are a pluripotent group of extracellular nanovesicles secreted by all cells that mediate intercellular communications. The effective information within exosomes is primarily reflected in exosomal cargos, including proteins, lipids, DNAs, and non-coding RNAs (ncRNAs), the most intensively studied molecules. Cardiac resident cells (cardiomyocytes, fibroblasts, and endothelial cells) and foreign cells (infiltrated immune cells, cardiac progenitor cells, cardiosphere-derived cells, and mesenchymal stem cells) are involved in the progress of ventricular remodeling (VR) following myocardial infarction (MI) via transferring exosomes into target cells. Here, we summarize the pathological mechanisms of VR following MI, including cardiac myocyte hypertrophy, cardiac fibrosis, inflammation, pyroptosis, apoptosis, autophagy, angiogenesis, and metabolic disorders, and the roles of exosomal cargos in these processes, with a focus on proteins and ncRNAs. Continued research in this field reveals a novel diagnostic and therapeutic strategy for VR.

Emerging roles of the RNA modifications N6-methyladenosine and adenosine-to-inosine in cardiovascular diseases

Cardiovascular diseases lead the mortality and morbidity disease metrics worldwide. A multitude of chemical base modifications in ribonucleic acids (RNAs) have been linked with key events of cardiovascular diseases and metabolic disorders. Named either RNA epigenetics or epitranscriptomics, the post-transcriptional RNA modifications, their regulatory pathways, components, and downstream effects substantially contribute to the ways our genetic code is interpreted. Here we review the accumulated discoveries to date regarding the roles of the two most common epitranscriptomic modifications, N6-methyl-adenosine (m6A) and adenosine-to-inosine (A-to-I) editing, in cardiovascular disease.

Plasma Exosomes Transfer miR-885-3p Targeting the AKT/NFκB Signaling Pathway to Improve the Sensitivity of Intravenous Glucocorticoid Therapy Against Graves Ophthalmopathy

Graves ophthalmopathy (GO), a manifestation of Graves' disease, is an organ-specific autoimmune disease. Intravenous glucocorticoid therapy (ivGCs) is the first-line treatment for moderate-to-severe and active GO. However, ivGCs is only effective in 70%-80% of GO patients. Insensitive patients who choose 12-week ivGCs not only were delayed in treatment but also took the risk of adverse reactions of glucocorticoids. At present, there is still a lack of effective indicators to predict the therapeutic effect of ivGCs. Therefore, the purpose of this study is to find biomarkers that can determine the sensitivity of ivGCs before the formulation of treatment, and to clarify the mechanism of its regulation of ivGCs sensitivity. This study first characterized the miRNA profiles of plasma exosomes by miRNA sequencing to identify miRNAs differentially expressed between GO patients with significant improvement (SI) and non-significant improvement (NSI) after ivGCs treatment. Subsequently, we analyzed the function of the predicted target genes of differential miRNAs. According to the function of the target genes, we screened 10 differentially expressed miRNAs. An expanded cohort verification showed that compared with NSI patients, mir-885-3p was upregulated and mir-4474-3p and mir-615-3p were downregulated in the exosomes of SI patients. Based on statistical difference and miRNA function, mir-885-3p was selected for follow-up study. The in vitro functional analysis of exosomes mir-885-3p showed that exosomes from SI patients (SI-exo) could transfer mir-885-3p to orbital fibroblasts (OFs), upregulate the GRE luciferase reporter gene plasmid activity and the level of glucocorticoid receptor (GR), downregulate the level of inflammatory factors, and improve the glucocorticoid sensitivity of OFs. Moreover, these effects can be inhibited by the corresponding miR inhibitor. In addition, we found that high levels of mir-885-3p could inhibit the AKT/NFκB signaling pathway, upregulate the GRE plasmid activity and GR level, and downregulate the level of inflammatory factors of OFs. Moreover, the improvement of glucocorticoid sensitivity by mir-885-3p transmitted by SI-exo can also be inhibited by the AKT/NFκB agonist. Finally, through the in vivo experiment of the GO mouse model, we further determined the relationship between exosomes' mir-885-3p sequence, AKT/NFκB signaling pathway, and glucocorticoid sensitivity. As a conclusion, plasma exosomes deliver mir-885-3p and inhibit the AKT/NFκB signaling pathway to improve the glucocorticoid sensitivity of OFs. Exosome mir-885-3p can be used as a biomarker to determine the sensitivity of ivGCs in GO patients.

Circulating microRNAs in patients with aneurysmal dilatation of coronary arteries

To understand the mechanism underlying coronary artery abnormal dilatation (CAAD), the present study identified and compared the expression of circulating microRNAs (miRNAs) in three groups of patients. Group 1 included 20 patients with CAAD, Group 2 included 20 patients with angiographically confirmed coronary artery disease (CAD), and Group 3 included 20 patients with normal coronary arteries (control). miRNAs were isolated from plasma samples and were profiled using PCR arrays and miRCURY LNA Serum/Plasma Focus PCR Panels. The present study demonstrated that the plasma miRNA levels were significantly different in Group 1 compared with in Group 2 and Group 3 (fold change >2 and P<0.05). The comparison of Group 1 with Group 3 identified 21 significantly upregulated and two downregulated miRNAs in patients with CAAD compared with in the control group. Moreover, six upregulated and two downregulated miRNAs were identified in patients with CAD compared with in the controls. The third comparison revealed four upregulated and three downregulated miRNAs in Group 1, when compared with patients with CAD. In conclusion, the present study identified a specific signature of plasma miRNAs, which were upregulated and downregulated in patients with CAAD compared with in patients with CAD and control individuals.

Validated Impacts of N6-Methyladenosine Methylated mRNAs on Apoptosis and Angiogenesis in Myocardial Infarction Based on MeRIP-Seq Analysis

Objectives: N6-methyladenosine (m⁶A) is hypothesized to play a role in the regulation of pathogenesis of myocardial infarction (MI). This study was designed to compare m⁶A-tagged transcript profiles to identify mRNA-specific changes on pathophysiological variations after MI.

Methods: N6-methyladenosine methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were interacted to select m⁶A-modified mRNAs with samples collected from sham operated and MI rat models. m⁶A methylation regulated mRNAs were interacted with apoptosis/angiogenesis related genes in GeneCards. Afterwards, MeRIP-quantitative real-time PCR (MeRIP-qRT-PCR) was performed to measure m⁶A methylation level of hub mRNAs. m⁶A methylation variation was tested under different oxygen concentration or hypoxic duration in H9c2 cells and HUVECs. In addition, Western blot and qRT-PCR were employed to detect expression of hub mRNAs and relevant protein level. Flow cytometry and Tunel assay were conducted to assess apoptotic level. CCK-8, EdU, and tube formation assay were performed to measure cell proliferation and tube formation ability.

Results: Upregulation of Mettl3 was firstly observed in vivo and in vitro, followed by upregulation of m⁶A methylation level. A total of 567 significantly changed m⁶A methylation peaks were identified, including 276 upregulated and 291 downregulated peaks. A total of 576 mRNAs were upregulated and 78 were downregulated. According to combined analysis of MeRIP-seq and RNA-seq, we identified 26 significantly hypermethylated and downregulated mRNAs. Based on qRT-PCR and interactive analysis, Hadh, Kcnn1, and Tet1 were preliminarily identified as hub mRNAs associated with apoptosis/angiogenesis. MeRIP-qRT-PCR assay confirmed the results from MeRIP-seq. With the inhibition of Mettl3 in H9c2 cells and HUVECs, downregulated m⁶A methylation level of total RNA and upregulated expression of hub mRNAs were observed. Increased m⁶A level was verified in the gradient context in terms of prolonged hypoxic duration and decreased oxygen concentration. Under simulated hypoxia, roles of Kcnn1 and Tet1 in angiogenesis and Hadh, Tet1, and Kcnn1 in apoptosis were further confirmed with our validation experiments.

Conclusion: Roles of m⁶A-modified mRNA transcripts in the context of MI were preliminarily verified. In the context of m⁶A methylation, three hub mRNAs were validated to impact the process of apoptosis/angiogenesis. Our study provided theoretical basis and innovative targets for treatment of MI and paved the way for future investigations aiming at exploring upstream epigenetic mechanisms of pathogenesis after MI.

Extracellular vesicles in cardiovascular disease: Biological functions and therapeutic implications

Extracellular vesicles (EVs), including exosomes and microvesicles, are lipid bilayer particles naturally released from the cell. While exosomes are formed as intraluminal vesicles (ILVs) of the multivesicular endosomes (MVEs) and released to extracellular space upon MVE-plasma membrane fusion, microvesicles are generated through direct outward budding of the plasma membrane. Exosomes and microvesicles have same membrane orientation, different yet overlapping sizes; their cargo contents are selectively packed and dependent on the source cell type and functional state. Both exosomes and microvesicles can transfer bioactive RNAs, proteins, lipids, and metabolites from donor to recipient cells and influence the biological properties of the latter. Over the last decade, their potential roles as effective inter-tissue communicators in cardiovascular physiology and pathology have been increasingly appreciated. In addition, EVs are attractive sources of biomarkers for the diagnosis and prognosis of diseases, because they acquire their complex cargoes through cellular processes intimately linked to disease pathogenesis. Furthermore, EVs obtained from various stem/progenitor cell populations have been tested as cell-free therapy in various preclinical models of cardiovascular diseases and demonstrate unequivocally encouraging benefits. Here we summarize the findings from recent research on the biological functions of EVs in the ischemic heart disease and heart failure, and their potential as novel diagnostic biomarkers and therapeutic opportunities.

Allicin protects against myocardial I/R by accelerating angiogenesis via the miR-19a-3p/PI3K/AKT axis

Objectives: Allicin is an allyl 2-propenethiosulfinate or diallyl thiosulfinate acid with cardioprotective effects in myocardial ischemia/reperfusion (MI/R) injury. This study aims to examine the underlying mechanism by which Allicin protects against MI/R.

Methods: C57BL6 mice were subjected to either sham or MI/R surgery, and mice in the Allicin group were injected with Allicin (5 mg/ml) before the induction of ischemia. The cardiac function and histopathology of experimental mice were evaluated by ultrasound quantification and Masson staining. We next measured the capillary angiogenesis of the peri-infarct area by Masson staining and immunohistochemical staining. The miRNA microarray was carried out to examine the expressed miRNAs in MI/R tissues and corresponding normal tissues. Real-time quantitative polymerase chain reaction (q-PCR) was performed to validate the selected miRNA-19α-3p gene expression. Besides, we evaluated the myocardial lactate dehydrogenase and COX-2 by immunofluorescence staining. The western blot analysis was used to evaluate the protein levels of p-AKT, p-PI3K, p-mTOR, COX-2, and VEGF protein in the Allicin and Model group. In vitro study, LPS stimulated Tie2 expressing macrophages were cultured in an ischemic buffer. We evaluated the accumulation of VEGF by fura-2/AM fluorescence. Besides, Western blotting was performed to examine the protein levels of p-PI3K, p-AKT, p-mTOR, VEGF, COX2, and MMP2. The PI3K inhibitor was applied to investigate whether Allicin-induced myocardial ischemia-reperfusion injury protection is mediated via the PI3K/AKT pathway. And the miR-19α-3p mimic/inhibitor were transfected to promote/inhibit the expression of miR-19a-3p for verifying the regulation of miR-19a-3p on PI3K pathway.

Results: Allicin pretreatment significantly improved I/R-induced cardiac function damage. Furthermore, Allicin could repress cardiac fibrosis, as evidenced by reduced areas of cardiac fibrosis. Allicin’s effect on the MI/R was associated with increased capillary angiogenesis. Microarray analysis exposed that miR-19a-3p down-regulated PIK3CA (PI3K) expression by directly targeting the PIK3CA gene. The regulation of the angiogenesis pathway and gene miRNA-19a-3p might affect the Allicin-induced MI/R protection. Immunofluorescence staining revealed that COX-2 and myocardial lactate dehydrogenase were significantly increased after Allicin treatment. Furthermore, western blot analysis demonstrated that p-AKT, p-PI3K, p-mTOR, COX-2, and VEGF protein levels were also increased in the Allicin group. In vitro study, the protein levels of p-PI3K, p-AKT, p-mTOR, VEGF, COX2, and MMP2 were significantly increased in the Allicin-treated Tie2 expressing macrophages. These effects were partially reversed by PI3K inhibitor (Wortmannin) treatment. MiR-19α-3p plays an important role in myocardial I/R injury. It could regulate the activity of the PI3K-AKT pathway. And inhibition of miR-19a-3p promoted angiogenesis by regulating PI3K/AKT pathway.

Conclusions: Allicin pretreatment protects against myocardial I/R and activating the miR-19a-3p/PI3K/AKT pathway.

MSCs-Derived Extracellular Vesicles Carrying miR-212-5p Alleviate Myocardial Infarction-Induced Cardiac Fibrosis via NLRC5/VEGF/TGF-β1/SMAD Axis

The purpose of the present study was to define the role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in the progression of myocardial infarction (MI)-induced cardiac fibrosis. An in vitro cell model of hypoxia-induced cardiac fibrosis was constructed in cardiac fibroblasts (CFs). miR-212-5p was poorly expressed in clinical pathological samples and animal models of cardiac fibrosis caused by MI, while miR-212-5p expression was enriched in EVs released from MSCs. EVs from MSCs were isolated, evaluated, and co-cultured with CFs. Dual-luciferase reporter gene assay revealed that miR-212-5p negatively targeted NLRC5 progression of cardiac fibrosis. Following loss- and gain-function assay, EVs expressing miR-212-5p protected against cardiac fibrosis evidenced by reduced levels of α-SMA, Collagen I, TGF-β1, and IL-1β. In vivo experiments further confirmed the above research results. Collectively, EVs from MSCs expressing miR-212-5p may attenuate MI by suppressing the NLRC5/VEGF/TGF-β1/SMAD axis.

Mesenchymal stem cell-derived exosome microRNA as therapy for cardiac ischemic injury

Cardiovascular diseases (CVD) are a significant cause of human health harm. In the past, stem cell therapy was reported to have functional defects, such as immune rejection, tumorigenicity, and infusion toxicity. Exosomes are extracellular vesicles with lipid bilayer membrane structure, containing proteins, lipids, mRNA, miRNA, DNA, and other molecules, which can mediate various biological functions such as immune response, inflammatory response, cell migration, and differentiation intercellular communication. Exosomal miRNAs have outstanding advantages in disease diagnosis and curative effect prediction. Likewise, paracrine factors could also mediate the main therapeutic effect of mesenchymal stem cells. Research has shown that mesenchymal stem cell-derived micro-exosomes, which may come from stem cells, accumulate in the ischemic tissue and regulate cell proliferation, apoptosis, inflammation, and angiogenesis sites of myocardial injury after being transplanted. This review reviewed the molecular mechanisms of exosomes and internal microRNAs derived from mesenchymal stem cells in cardiac ischemic injury repair.

Inhibition of SENP2-mediated Akt deSUMOylation promotes cardiac regeneration via activating Akt pathway

Post-translational modification (PTM) by small ubiquitin-like modifier (SUMO) is a key regulator of cell proliferation and can be readily reversed by a family of SUMO-specific proteases (SENPs), making SUMOylation an ideal regulatory mechanism for developing novel therapeutic strategies for promoting a cardiac regenerative response. However, the role of SUMOylation in cardiac regeneration remains unknown. In the present study, we assessed whether targeting protein kinase B (Akt) SUMOylation can promote cardiac regeneration. Quantitative PCR and Western blotting results showed that small ubiquitin-like modifier-specific protease 2 (SENP2) is up-regulated during postnatal heart development. SENP2 deficiency promoted P7 and adult cardiomyocyte (CM) dedifferentiation and proliferation both in vitro and in vivo. Mice with SENP2 deficiency exhibited improved cardiac function after MI due to CM proliferation and angiogenesis. Mechanistically, the loss of SENP2 up-regulated Akt SUMOylation levels and increased Akt kinase activity, leading to a decrease in GSK3β levels and subsequently promoting CM proliferation and angiogenesis. In summary, inhibition of SENP2-mediated Akt deSUMOylation promotes CM differentiation and proliferation by activating the Akt pathway. Our results provide new insights into the role of SUMOylation in cardiac regeneration.