Exosomes as a messager to regulate the crosstalk between macrophages and cardiomyocytes under hypoxia conditions

The effect of macrophages and their exosomes in ischemic heart disease

Ischemic heart disease (IHD) is a leading cause of disability and death worldwide, with immune regulation playing a crucial role in its pathogenesis. Various immune cells are involved, and as one of the key immune cells residing in the heart, macrophages play an indispensable role in the inflammatory and reparative processes during cardiac ischemia. Exosomes, extracellular vesicles containing lipids, nucleic acids, proteins, and other bioactive molecules, have emerged as important mediators in the regulatory functions of macrophages and hold promise as a novel therapeutic target for IHD. This review summarizes the regulatory mechanisms of different subsets of macrophages and their secreted exosomes during cardiac ischemia over the past five years. It also discusses the current status of clinical research utilizing macrophages and their exosomes, as well as strategies to enhance their therapeutic efficacy through biotechnology. The aim is to provide valuable insights for the treatment of IHD.

M2 macrophage‑derived exosomes alleviate KCa3.1 channel expression in rapidly paced HL‑1 myocytes via the NF‑κB (p65)/STAT3 signaling pathway

The present study was designed to explore the role of M2 macrophage‑derived exosomes (M2‑exos) on the KCa3.1 channel in a cellular atrial fibrillation (AF) model using rapidly paced HL‑1 myocytes. M2 macrophages and M2‑exos were isolated and identified. MicroRNA (miR)‑146a‑5p levels in M2 macrophages and M2‑exos were quantified using reverse transcription‑quantitative PCR (RT‑qPCR). HL‑1 myocytes were randomly divided into six groups: Control group, pacing group, pacing + coculture group (pacing HL‑1 cells cocultured with M2‑exos), pacing + mimic‑miR‑146a‑5p group, pacing + NC‑miR‑146a‑5p group and pacing + pyrrolidine dithiocarbamate (PDTC; a special blocker of the NF‑κB signaling pathway) group. Transmission electron microscopy, nanoparticle tracking analysis, western blotting, RT‑qPCR and immunohistochemistry were performed in the present study. A whole‑cell clamp was also applied to record the current density of KCa3.1 and action potential duration (APD) in each group. The results revealed that miR‑146a‑5p was highly expressed in both M2 macrophages and M2‑exos. Pacing HL‑1 cells led to a shorter APD, an increased KCa3.1 current density and higher protein levels of KCa3.1, phosphorylated (p‑)NF‑κB p65, p‑STAT3 and IL‑1β compared with the control group. M2‑exos, miR‑146a‑5p‑mimic and PDTC both reduced the protein expression of KCa3.1, p‑NF‑κB p65, p‑STAT3 and IL‑1β and the current density of KCa3.1, resulting in a longer APD in the pacing HL‑1 cells. In conclusion, M2‑exos and their cargo, which comprised miR‑146a‑5p, decreased KCa3.1 expression and IL‑1β secretion in pacing HL‑1 cells via the NF‑κB/STAT3 signaling pathway, limiting the shorter APD caused by rapid pacing.

LncRNA CCRR Attenuates Postmyocardial Infarction Inflammatory Response by Inhibiting the TLR Signalling Pathway

BACKGROUND

Timely and proper suppression of inflammation can effectively reduce myocardial injury and promote the postmyocardial infarction (post-MI) wound-healing process. We have previously found that cardiac conduction regulatory RNA (CCRR), a long noncoding RNA (lncRNA) transcribed by the gene located on chromosome 9, with abundant expression in the heart, elicits antiarrhythmic effects in heart failure, and this is a continuing study on the role of CCRR in MI.

METHODS

CCRR was overexpressed in CCRR transgenic mice or after injection of adeno-associated virus-9 (AAV-9). MI surgery was performed, and cardiac function was assessed in vivo by echocardiography, followed by histologic analyses. Western blot analysis and qRT-PCR were performed to investigate the effects of CCRR on macrophages, cardiomyocytes, and cardiomyocytes cocultured with macrophages. Through microarray analysis and RNA-binding protein immunoprecipitation (RIP) and other related techniques were also employed to study the effects of CCRR on Toll-like receptor (TLR)2 and TLR4.

RESULTS

We found that CCRR level was significantly decreased with increases in proinflammatory cytokines and activation of the TLR signalling pathway in the heart of the 3-day MI mice. CCRR overexpression downregulated TLR2 and TLR4 in MI and effectively inhibited the inflammatory responses in primary cardiomyocytes and macrophages cultured under hypoxic conditions. Downregulation of CCRR induced excessive inflammatory responses by activating the TLR signalling pathway. CCRR acted by suppressing TLR2 and TLR4 to inhibit the secretion of proinflammatory factors to reduce infarct size, thereby improving cardiac function.

CONCLUSIONS

CCRR protected cardiomyocytes against MI injury by suppressing inflammatory response through targeting the TLR signalling pathway.

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.

Exosomes and their derivatives as biomarkers and therapeutic delivery agents for cardiovascular diseases: Situations and challenges

Microvesicles known as exosomes have a diameter of 40 to 160 nm and are derived from small endosomal membranes. Exosomes have attracted increasing attention over the past ten years in part because they are functional vehicles that can deliver a variety of lipids, proteins, and nucleic acids to the target cells they encounter. Because of this function, exosomes may be used for the diagnosis, prognosis and treatment of many diseases. All throughout the world, cardiovascular diseases (CVDs) continue to be a significant cause of death. Because exosomes are mediators of communication between cells, which contribute to many physiological and pathological aspects, they may aid in improving CVD therapies as biomarkers for diagnosing and predicting CVDs. Many studies demonstrated that exosomes are associated with CVDs, such as coronary artery disease, heart failure, cardiomyopathy and atrial fibrillation. Exosomes participate in the progression or inhibition of these diseases mainly through the contents they deliver. However, the application of exosomes in diferent CVDs is not very mature. So further research is needed in this field.

Hypoxic regulation of extracellular vesicles: Implications for cancer therapy

Extracellular vesicles (EVs) play a pivotal role in intercellular communication and have been implicated in cancer progression. Hypoxia, a pervasive hallmark of cancer, is known to regulate EV biogenesis and function. Hypoxic EVs contain a specific set of proteins, nucleic acids, lipids, and metabolites, capable of reprogramming the biology and fate of recipient cells. Enhancing the intrinsic therapeutic efficacy of EVs can be achieved by strategically modifying their structure and contents. Moreover, the use of EVs as drug delivery vehicles holds great promise for cancer treatment. However, various hurdles must be overcome to enable their clinical application as cancer therapeutics. In this review, we aim to discuss the current knowledge on the hypoxic regulation of EVs. Additionally, we will describe the underlying mechanisms by which EVs contribute to cancer progression in hypoxia and outline the progress and limitations of hypoxia-related EV therapeutics for cancer.

Loss of Histone Methyltransferase KMT2D Attenuates Angiogenesis in the Ischemic Heart by Inhibiting the Transcriptional Activation of VEGF-A

Angiogenesis occurred after myocardial infarction (MI) protects heart failure (HF). The aim of our study was to explore function of histone methyltransferase KMT2D (MLL4, mixed-lineage leukemia 4) in angiogenesis post-MI. Western blotting showed that KMT2D protein expression was elevated in MI mouse myocardial. Cardiomyocyte-specific Kmt2d-knockout (Kmt2d-cKO) mice were generated, and echocardiography and immunofluorescence staining detected significantly attenuated cardiac function and insufficient angiogenesis following MI in Kmt2d-cKO mice. Cross-talk assay suggested that Kmt2d-KO H9c2-derived conditioned medium attenuates EA.hy926 EC function. ELISA further identified that VEGF-A released from Kmt2d-KO H9c2 was significantly reduced. CUT&Tag and RT-qPCR revealed that KMT2D deficiency reduced Vegf-a mRNA expression and enrichment of H3K4me1 on the Vegf-a promoter. Moreover, KMT2D silencing in ECs also suppressed endothelial function. Our study indicates that KMT2D depletion in both cardiomyocytes and ECs attenuates angiogenesis and that loss of KMT2D exacerbates heart failure after MI in mice.

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.

Exosomal Non-Coding RNA Mediates Macrophage Polarization: Roles in Cardiovascular Diseases

Extracellular vesicles (EVs) or exosomes are nanosized extracellular particles that contain proteins, DNA, non-coding RNA (ncRNA) and other molecules, which are widely present in biofluids throughout the body. As a key mediator of intercellular communication, EVs transfer their cargoes to target cells and activate signaling transduction. Increasing evidence shows that ncRNA is involved in a variety of pathological and physiological processes through various pathways, particularly the inflammatory response. Macrophage, one of the body's "gatekeepers", plays a crucial role in inflammatory reactions. Generally, macrophages can be classified as pro-inflammatory type (M1) or anti-inflammatory type (M2) upon their phenotypes, a phenomenon termed macrophage polarization. Increasing evidence indicates that the polarization of macrophages plays important roles in the progression of cardiovascular diseases (CVD). However, the role of exosomal ncRNA in regulating macrophage polarization and the role of polarized macrophages as an important source of EV in CVD remains to be elucidated. In this review, we summarize the role and molecular mechanisms of exosomal-ncRNA in regulating macrophage polarization during CVD development, focusing on their cellular origins, functional cargo, and their detailed effects on macrophage polarization. We also discuss the role of polarized macrophages and their derived EV in CVD as well as the therapeutic prospects of exosomal ncRNA in the treatment of CVD.

Mesenchymal stem cell-derived exosomes in cardiovascular and cerebrovascular diseases: From mechanisms to therapy

Cardiovascular and cerebrovascular diseases (CVDs) remain an intractable problem and have high morbidity and mortality worldwide, as well as substantial health and economic burdens, representing an urgent clinical need. In recent years, the focus of research has shifted from the use of mesenchymal stem cells (MSCs) for transplantation to the use of their secretory exosomes (MSC-exosomes) for the treatment of numerous CVDs, including atherosclerosis, myocardial infarction (MI), heart failure (HF), ischemia/reperfusion (I/R), aneurysm, and stroke. MSCs are pluripotent stem cells with multiple differentiation pathways that exert pleiotropic effects by producing soluble factors, the most effective components of which are exosomes. MSC-exosomes are considered to be an excellent and promising cell-free therapy for CVDs due to their higher circulating stability, improved biocompatibility, reduced toxicity, and immunogenicity. In addition, exosomes play critical roles in repairing CVDs by inhibiting apoptosis, regulating inflammation, ameliorating cardiac remodeling, and promoting angiogenesis. Herein, we describe knowledge about the biological characteristics of MSC-exosomes, investigate the mechanism by which MSC-exosomes mediate therapeutic repair, and summarize recent advances in the efficacy of MSC-exosomes in CVDs, with a view toward future clinical applications.

Illuminating the Molecular Intricacies of Exosomes and ncRNAs in Cardiovascular Diseases: Prospective Therapeutic and Biomarker Potential

Cardiovascular diseases (CVDs) are one of the leading causes of death worldwide. Accumulating evidences have highlighted the importance of exosomes and non-coding RNAs (ncRNAs) in cardiac physiology and pathology. It is in general consensus that exosomes and ncRNAs play a crucial role in the maintenance of normal cellular function; and interestingly it is envisaged that their potential as prospective therapeutic candidates and biomarkers are increasing rapidly. Considering all these aspects, this review provides a comprehensive overview of the recent understanding of exosomes and ncRNAs in CVDs. We provide a great deal of discussion regarding their role in the cardiovascular system, together with providing a glimpse of ideas regarding strategies exploited to harness their potential as a therapeutic intervention and prospective biomarker against CVDs. Thus, it could be envisaged that a thorough understanding of the intricacies related to exosomes and ncRNA would seemingly allow their full exploration and may lead clinical settings to become a reality in near future.

Paediatric pre-B acute lymphoblastic leukaemia-derived exosomes regulate immune function in human T cells

Exosomes derived from solid tumour cells are involved in immune suppression, angiogenesis and metastasis; however, the role of leukaemia‐derived exosomes has less been investigated. Hence, changes in immune response‐related genes and human T cells apoptosis co‐incubated with exosomes isolated from patients' pre‐B cell acute lymphoblastic leukaemia were evaluated in this in vitro study. Vein blood sample was obtained from each newly diagnosed acute lymphoblastic leukaemia (ALL) patient prior any therapy. ALL serum exosomes were isolated by ultrafiltration and characterized using Western blotting and transmission electron microscopy. Exosomes were then co‐incubated with T lymphocytes and the gene expressions, as well as functions of human T cells were quantified by qRT‐PCR. Apoptosis and caspase‐3 and caspase‐9 protein expression were also evaluated by flowcytometry and Western blotting analysis, respectively. Exosomes isolated from ALL patients affected T lymphocytes and elevated the apoptosis. Moreover, these exosomes altered the T cells profile into regulatory type by increasing the expression of FOXP3 and Tregs‐related cytokines, including TGF‐B and IL‐10. The expression level of Th17‐related transcription factors (RoRγt) and interleukins (IL‐17 and IL‐23) decreased after this treatment. According to our findings, exosomes derived from ALL patients' sera carry immunosuppressive molecules, indicating the possible effect of exosomes as liquid biomarkers for cancer staging.

Muscle and Adipose Tissue Communicate with Extracellular Vesicles

In numerous body locations, muscle and adipose tissue are in close contact. Both tissues are endocrine organs that release cytokines, playing a crutial role in the control of tissue homeostasis in health and diseases. Within this context, the identification of the signals involved in muscle–fat crosstalk has been a hot topic over the last 15 years. Recently, it has been discovered that adipose tissue and muscles can release information embedded in lipid-derived nanovesicles called ‘extracellular vesicles’ (EVs), which can modulate the phenotype and the homeostasis of neighboring recipient cells. This article reviews knowledge on EVs and their involvement in the communication between adipose tissue and muscle in several body locations. Even if the works are scarce, they have revolutionized our vision in the field of metabolic and cardiovascular diseases.

Hypoxia Induced Changes of Exosome Cargo and Subsequent Biological Effects

Exosomes are small extracellular vesicles that are secreted by almost all types of cells and exist in almost all extracellular spaces. As an important mediator of intercellular communication, exosomes encapsulate the miRNA, lncRNA, cirRNA, mRNA, cytokine, enzyme, lipid, and other components from the cytoplasm into its closed single membrane structure and transfer them to recipient units in an autocrine, paracrine, or endocrine manner. Hypoxia is a state of low oxygen tension and is involved in many pathological processes. Hypoxia influences the size, quantity, and expression of exosome cargos. Exosomes derived from hypoxic tumor cells transfer genetics, proteins, and lipids to the recipient units to exert pleiotropic effects. Different donor cells produce different cargo contents, target different recipient units and lead to different biological effects. Hypoxic exosomes derived from tumor cells uptaken by normoxic tumor cells lead to promoted proliferation, migration, and invasion; uptaken by extracellular space or liver lead to promoted metastasis; uptaken by endothelial cells lead to promoted angiogenesis; uptaken by immune cells lead to promoted macrophage polarization and changed tumor immune microenvironment. In addition to various types of tumors, hypoxic exosomes also participate in the development of diseases in the cardiovascular system, neuron system, respiratory system, hematology system, endocrine system, urinary system, reproduction system, and skeletomuscular system. Understanding the special characteristics of hypoxic exosomes provide new insight into elaborating the pathogenesis of hypoxia related disease. This review summarizes hypoxia induced cargo changes and the biological effects of hypoxic exosomes in tumors and non-malignant diseases in different systems.

A Novel, Cell-Free Therapy to Enter Our Hearts: The Potential Role of Small EVs in Prevention and Treatment of CVD

Heart disease constitutes one of the leading causes of morbidity and mortality worldwide. Current therapeutic techniques, such as interventional revascularization, although lifesaving, come along with myocardial injury related to the reperfusion itself, called ischemia-reperfusion injury, which is an added factor for increased morbidity. For that reason, there is an imperative need for novel therapies to be developed that would either prevent or treat myocardial injury. Extracellular vesicles (EVs), specifically small EVs (sEVs), have proven to be important mediators of intercellular communication. The fact that they carry information reflecting that of the parental cell makes them an ideal candidate for diagnostic purposes. sEVs derived from immunoregulatory cells, such as mesenchymal stem cells or cardiac progenitor cells, could also be used therapeutically to exert the primary immunomodulatory function but without carrying the side effects related to cell therapy. Furthermore, as a natural product, they have the added advantage of low immunogenicity, offering the potential for safe drug delivery. In the field of cardiology, there has been great interest in the therapeutic and diagnostic potential of sEVs with significant translational potential. Here, we review the potential use of sEVs in the context of myocardial ischemia and ischemia-reperfusion injury.