Functional Role of Cardiovascular Exosomes in Myocardial Injury and Atherosclerosis

The novel insights of epithelial-derived exosomes in various fibrotic diseases

The characteristics of fibrosis include the abnormal accumulation of extracellular matrix proteins and abnormal tissue repair caused by injury, infection, and inflammation, leading to a significant increase in organ failure and mortality. Effective and precise treatments are urgently needed to halt and reverse the progression of fibrotic diseases. Exosomes are tiny vesicles derived from endosomes, spanning from 40 to 160 nanometers in diameter, which are expelled into the extracellular matrix environment by various cell types. They play a crucial role in facilitating cell-to-cell communication by transporting a variety of cargoes, including proteins, RNA, and DNA. Epithelial cells serve as the primary barrier against diverse external stimuli that precipitate fibrotic diseases. Numerous research suggests that exosomes from epithelial cells have a significant impact on several fibrotic diseases. An in-depth comprehension of the cellular and molecular mechanisms of epithelial cell-derived exosomes in fibrosis holds promise for advancing the exploration of novel diagnostic biomarkers and clinical drug targets. In this review, we expand upon the pathogenic mechanisms of epithelium-derived exosomes and highlight their role in the fibrotic process by inducing inflammation and activating fibroblasts. In addition, we are particularly interested in the bioactive molecules carried by epithelial-derived exosomes and their potential value in the diagnosis and treatment of fibrosis and delineate the clinical utility of exosomes as an emerging therapeutic modality, highlighting their potential application in addressing various medical conditions.

Aging and Metabolic Reprogramming of Adipose-Derived Stem Cells Affect Molecular Mechanisms Related to Cardiovascular Diseases

We performed a systematic search of the PubMed database for English-language articles related to the function of adipose-derived stem cells in the pathogenesis of cardiovascular diseases. In preclinical models, adipose-derived stem cells protected arteries and the heart from oxidative stress and inflammation and preserved angiogenesis. However, clinical trials did not reiterate successful treatments with these cells in preclinical models. The low success in patients may be due to aging and metabolic reprogramming associated with the loss of proliferation capacity and increased senescence of stem cells, loss of mitochondrial function, increased oxidative stress and inflammation, and adipogenesis with increased lipid deposition associated with the low potential to induce endothelial cell function and angiogenesis, cardiomyocyte survival, and restore heart function. Then, we identify noncoding RNAs that may be mechanistically related to these dysfunctions of human adipose-derived stem cells. In particular, a decrease in let-7, miR-17-92, miR-21, miR-145, and miR-221 led to the loss of their function with obesity, type 2 diabetes, oxidative stress, and inflammation. An increase in miR-34a, miR-486-5p, and mir-24-3p contributed to the loss of function, with a noteworthy increase in miR-34a with age. In contrast, miR-146a and miR-210 may protect stem cells. However, a systematic analysis of other noncoding RNAs in human adipose-derived stem cells is warranted. Overall, this review gives insight into modes to improve the functionality of human adipose-derived stem cells.

Mesenchymal stem cell-derived exosomes: a possible therapeutic strategy for repairing heart injuries

Mesenchymal stem cells (MSCs) are one of the most potent therapeutic strategies for repairing cardiac injury. It has been shown in the latest studies that MSCs cannot survive in the heart for a long time. Consequently, the exosomes secreted by MSCs may dominate the repair of heart injury and promote the restoration of cardiac cells, vascular proliferation, immune regulation, etc. Based on the current research, the progress of the acting mechanism, application prospects and challenges of exosomes, including non-coding RNA, in repairing cardiac injuries are summarised in this article.

Exo-III Enzyme and DNAzyme-Assisted Dual Signal Recycles for Sensitive Analysis of Exosomes by Using Personal Glucose Meter

Exosome plays a crucial role in regulating intercellular communication during atherosclerosis development. However, sensitive and portable exosome detection remains a huge challenge. Herein, a personal glucose meter (PGM)-based exosomes detection approach has been proposed that allows detection of exosomes with a high sensitivity and reproducibility. In this method, a catch probe, which is composed of CD63 aptamer and blocker sequence, is utilized for the specific identification of exosomes. The blocker sequence binds with H probe to initiate the Exo-III-assisted signal recycles to generate numerous DNAzyme sequences. Under the assistance of the substrate, DNAzyme forms its active secondary structure to generate gap site in substrate, releasing a linker to conjugate sucrase to streptavidin magnetic beads (SMBs). After removing unbound sucrase, the SMB-linker-sucrase complex is used to catalyze sucrose to glucose, which can be read by PGMs. Based on this, the method exhibits a wide detection range and a low limit of detection, holding a promising prospect for the analysis of exosomes and screening atherosclerosis.

Extracellular Vesicles and Ischemic Cardiovascular Diseases

Characterized by coronary artery obstruction or stenosis, ischemic cardiovascular diseases as advanced stages of coronary heart diseases commonly lead to left ventricular aneurysm, ventricular septal defect, and mitral insufficiency. Extracellular vesicles (EVs) secreted by diverse cells in the body exert roles in cell-cell interactions and intrinsic cellular regulations. With a lipid double-layer membrane and biological components such as DNA, protein, mRNA, microRNAs (miRNA), and siRNA inside, the EVs function as paracrine signaling for the pathophysiology of ischemic cardiovascular diseases and maintenance of the cardiac homeostasis. Unlike stem cell transplantation with the potential tumorigenicity and immunogenicity, the EV-based therapeutic strategy is proposed to satisfy the demand for cardiac repair and regeneration while the circulating EVs detected by a noninvasive approach can act as precious biomarkers. In this chapter, we extensively summarize the cardioprotective functions of native EVs and bioengineered EVs released from stem cells, cardiomyocytes, cardiac progenitor cells (CPCs), endothelial cells, fibroblast, smooth muscle cells, and immune cells. In addition, the potential of EVs as robust molecule biomarkers is discussed for clinical diagnosis of ischemic cardiovascular disease, attributed to the same pathology of EVs as that of their origin. Finally, we highlight EV-based therapy as a biocompatible alternative to direct cell-based therapy for ischemic cardiovascular diseases.

Extracellular vesicles in vascular remodeling

Vascular remodeling contributes to the development of a variety of vascular diseases including hypertension and atherosclerosis. Phenotypic transformation of vascular cells, oxidative stress, inflammation and vascular calcification are closely associated with vascular remodeling. Extracellular vesicles (EVs) are naturally released from almost all types of cells and can be detected in nearly all body fluids including blood and urine. EVs affect vascular oxidative stress, inflammation, calcification, and lipid plaque formation; and thereby impact vascular remodeling in a variety of cardiovascular diseases. EVs may be used as biomarkers for diagnosis and prognosis, and therapeutic strategies for vascular remodeling and cardiovascular diseases. This review includes a comprehensive analysis of the roles of EVs in the vascular remodeling in vascular diseases, and the prospects of EVs in the diagnosis and treatment of vascular diseases.

Cardiac fibroblasts secrete exosome microRNA to suppress cardiomyocyte pyroptosis in myocardial ischemia/reperfusion injury

Molecular mechanisms underlying myocardial ischemia/reperfusion (MI/R) injury and effective strategies to treat MI/R injury are both in shortage. Although pyroptosis of cardiomyocytes and the protective role of cardiac fibroblasts (CFs) have been well recognized as targets to reduce MI/R injury and sudden cardiac death (SCD), the connection has not yet been established. Here, we showed that CFs protected cardiomyocytes against MI/R-induced injury through suppression of pyroptosis. A novel molecular mechanism underpinning this effect was further identified. Under hypoxia/reoxygenation condition, CFs were found to secrete exosomes, which contain increased level of microRNA-133a (miR-133a). These exosomes then delivered miR-133a into cardiomyocytes to target ELAVL1 and repressed cardiomyocyte pyroptosis. Based on this finding, we successfully developed a new strategy that used exosomes derived from CFs with overexpressed miR-133a to enhance the therapeutic outcomes for the MI/R injury. Overall, our results provide a novel molecular basis for understanding and treating MI/R injury, and our study also provides novel insight for the postmortem diagnosis of MI/R injury induced SCD by using exosome biomarker in forensic.

Intralesional Infiltrations of Arteriosclerotic Tissue Cells-Free Filtrate Reproduce Vascular Pathology in Healthy Recipient Rats

Lower-extremity arterial disease is a major health problem with increasing prevalence, often leading to non-traumatic amputation, disability and mortality. The molecular mechanisms underpinning abnormal vascular wall remodeling are not fully understood. We hypothesized on the existence of a vascular tissue memory that may be transmitted through soluble signaling messengers, transferred from humans to healthy recipient animals, and consequently drive the recapitulation of arterial wall thickening and other vascular pathologies. We examined the effects of the intralesional infiltration for 6 days of arteriosclerotic popliteal artery-derived homogenates (100 µg of protein) into rats’ full-thickness wounds granulation tissue. Animals infiltrated with normal saline solution or healthy brachial arterial tissue homogenate obtained from traumatic amputation served as controls. The significant thickening of arteriolar walls was the constant outcome in two independent experiments for animals receiving arteriosclerotic tissue homogenates. This material induced other vascular morphological changes including an endothelial cell phenotypic reprogramming that mirrored the donor’s vascular histopathology. The immunohistochemical expression pattern of relevant vascular markers appeared to match between the human tissue and the corresponding recipient rats. These changes occurred within days of administration, and with no cross-species limitation. The identification of these “vascular disease drivers” may pave novel research avenues for atherosclerosis pathobiology.

Extracellular Vesicles: An Emerging Mechanism Governing the Secretion and Biological Roles of Tenascin-C

ECM composition and architecture are tightly regulated for tissue homeostasis. Different disorders have been associated to alterations in the levels of proteins such as collagens, fibronectin (FN) or tenascin-C (TnC). TnC emerges as a key regulator of multiple inflammatory processes, both during physiological tissue repair as well as pathological conditions ranging from tumor progression to cardiovascular disease. Importantly, our current understanding as to how TnC and other non-collagen ECM components are secreted has remained elusive. Extracellular vesicles (EVs) are small membrane-bound particles released to the extracellular space by most cell types, playing a key role in cell-cell communication. A broad range of cellular components can be transported by EVs (e.g. nucleic acids, lipids, signalling molecules and proteins). These cargoes can be transferred to target cells, potentially modulating their function. Recently, several extracellular matrix (ECM) proteins have been characterized as bona fide EV cargoes, exosomal secretion being particularly critical for TnC. EV-dependent ECM secretion might underpin diseases where ECM integrity is altered, establishing novel concepts in the field such as ECM nucleation over long distances, and highlighting novel opportunities for diagnostics and therapeutic intervention. Here, we review recent findings and standing questions on the molecular mechanisms governing EV–dependent ECM secretion and its potential relevance for disease, with a focus on TnC.

Stem cell-derived exosomes: Role in the pathogenesis and treatment of atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory vascular disease characterized by the accumulation of lipids and inflammatory debris in large arteries, high morbidity, and AS-related disease mortality. AS is a complex process, involving endothelial cell dysfunction and inflammation, smooth muscle cell proliferation, and macrophage activation. However, the currently available therapies for AS are not ideal, thus requiring development of novel treatment strategies. Exosomes are bi-lipid membranous extracellular containing multifarious cargo, such as proteins, lipids, micro ribonucleic acid (miRNAs), messenger RNAs, and long non-coding RNAs. Moreover, exosomes reportedly participate in various AS processes. Specifically, stem cell-derived exosomes can regulate the occurrence and development of AS, exhibiting the ability to overcome the limitations associated with AS treatment and stem cell therapy. In this paper, we review the pathological mechanism of AS and discuss the role of exosomes and stem cell-derived exosomes in AS progression. We conclude by suggesting new therapeutic strategies for treating AS with stem cell-derived exosomes in the hope of improving the clinical treatment of AS.

Exosomes as mediators and biomarkers in fibrosis

Fibrosis is characterized by aberrant myofibroblast accumulation and excessive extracellular matrix deposition, which leads to organ failure and significantly contributes to mortality worldwide. Exosomes, which are extracellular nanovesicles with a diameter of 30-100 nm that are secreted into the extracellular space by various types of cells, facilitate intercellular communication by delivering different cargos such as proteins, mRNAs and microRNAs. Growing evidence indicates that exosomes play an important role in various fibrotic diseases. A deeper understanding of the effects of exosomes in fibrosis may help in exploring new diagnostic and therapeutic targets. In this review, we summarize recent findings on exosomes in fibrotic diseases, with a special focus on exosomal cargo dysregulation and their potential diagnostic and therapeutic value in fibrosis.

Cardiovascular Exosomes and MicroRNAs in Cardiovascular Physiology and Pathophysiology

Cardiac exosomes mediate cell-to-cell communication, stimulate or inhibit the activities of target cells, and affect myocardial hypertrophy, injury and infarction, ventricular remodeling, angiogenesis, and atherosclerosis. The exosomes that are released in the heart from cardiomyocytes, vascular cells, fibroblasts, and resident stem cells are hypoimmunogenic, are physiologically more stable than cardiac cells, can circulate in the body, and are able to cross the blood-brain barrier. Exosomes utilize three mechanisms for cellular communication: (1) internalization by cells, (2) direct fusion to the cell membrane, and (3) receptor-ligand interactions. Cardiac exosomes transmit proteins, mRNA, and microRNAs to other cells during both physiological and pathological process. Cardiac-specific exosome miRNAs can regulate the expression of sarcomeric genes, ion channel genes, autophagy, anti-apoptotic and anti-fibrotic activity, and angiogenesis. This review discusses the role of exosomes and microRNAs in normal myocardium, myocardial injury and infarction, atherosclerosis, and the importance of circulating microRNAs as biomarkers of cardiac disease. Graphical Abstract.

Platelet-Derived Exosomal MicroRNA-25-3p Inhibits Coronary Vascular Endothelial Cell Inflammation Through Adam10 via the NF-κB Signaling Pathway in ApoE-/- Mice

Introduction: Coronary artery disease originates from the blockage of the inner walls of the coronary arteries due to a plaque buildup. Accumulating studies have highlighted the role of microRNAs (miRs) delivered by exosomes in the progression of coronary artery disease. Thus, the current study was to elucidate the role and mechanism by which miR-25-3p influences oxidized low density lipoprotein (ox-LDL)-induced coronary vascular endothelial cell (CVEC) inflammation. Methods: Primarily isolated CVECs were treated with ox-LDL to induce inflammation. Atherosclerosis models were induced in ApoE-/- mice and the peripheral blood platelet exosomes (PLT-Exo) were extracted and induced by thrombin, followed by co-culture with CVECs. The relationship between miR-25-3p and A disintegrin and metalloprotease 10 (Adam10) as well as the involvement of the NF-κB signaling pathway was evaluated. In order to evaluate the effect of PLT-Exo containing miR-25-3p on ox-LDL-induced CVEC inflammation, lipid accumulation and fibrosis, miR-25-3p mimic/inhibitor (in vitro), miR-25-3p agomir (in vivo), and si-Adam10 were delivered. Results: MiR-25-3p was expressed poorly in ox-LDL-induced CVECs and vascular tissues but exhibited high levels of expression in thrombin-induced PLT-Exo of atherosclerosis models of ApoE-/- mice. CVECs endocytosed PLT-Exo upregulated the miR-25-3p expression. Adam10 was identified as a target gene of miR-25-3p. The thrombin-induced activated PLT-Exo carrying miR-25-3p reduced Adam10 expression to inhibit ox-LDL-induced CVEC inflammation and lipid deposition through downregulating levels of α-smooth muscle actin, Collagen I a1, Collagen III a1, triglycerides, total cholesterol, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. Furthermore, the NF-κB signaling pathway participated in the inhibitory effect of PLT-Exo carrying miR-25-3p. Conclusion: Collectively, PLT-Exo overexpressing miR-25-3p attenuates ox-LDL-induced CVEC inflammation in ApoE-/- mouse models of atherosclerosis.

Exosomes in Systemic Sclerosis: Messengers Between Immune, Vascular and Fibrotic Components?

Systemic sclerosis (SSc) is a rare autoimmune disease, characterized by vasculopathy and fibrosis of the skin and internal organs. This disease is still considered incurable and is associated with a high risk of mortality, which is related to fibrotic events. An early diagnosis is useful for preventing complications, and targeted therapies reduce disease progression and ameliorate patients’ quality of life. Nevertheless, there are no validated biomarkers for early diagnosis with predictive prognostic value. Exosomes are membrane vesicles, transporting proteins and nucleic acids that may be delivered to target cells, which influences cellular behavior. They play important roles in cell–cell communication, both in physiological and pathological conditions, and may be useful as circulating biomarkers. Recent evidences suggest a role for these microvesicles in the three main aspects related to the pathogenesis of SSc (immunity, vascular damage, and fibrosis). Moreover, exosomes are of particular interest in the field of nano-delivery and are used as biological carriers. In this review, we report the latest information concerning SSc pathogenesis, clinical aspects of SSc, and current approaches to the treatment of SSc. Furthermore, we indicate a possible role of exosomes in SSc pathogenesis and suggest their potential use as diagnostic and prognostic biomarkers, as well as therapeutic tools.

Cardiomyocyte-Derived Exosomes: Biological Functions and Potential Therapeutic Implications

Exosomes, which are membrane-enclosed nanovesicles released by almost all cell types, have been recognized to play important roles in mediating cell-cell communication. In recent years, the physiological and pathological effects of exosomes on cardiovascular disease have been extensively studied. Exosomes can transfer proteins, mRNAs, microRNAs, and other bioactive molecules to recipient cells to influence their biological properties. In recent years, accumulating evidence has suggested that cardiomyocyte-derived exosomes play an important role in the progression of cardiovascular disease. Here, we summarize the functional roles of cardiomyocyte-derived exosomes in cardiovascular physiology and pathology.

Extracellular vesicles in atherosclerosis

Extracellular vesicles (EVs), which exist in human blood, are increased in some inflammation-related cardiovascular diseases. EVs are involved in inflammation, immunity, signal transduction, cell survival and apoptosis, angiogenesis, thrombosis, and autophagy, all of which are highly significant for maintaining homeostasis and disease progression. Therefore, EVs are also associated with key steps in atherosclerosis, including cellular lipid metabolism, endothelial dysfunction and vascular wall inflammation, ultimately resulting in vascular remodelling. In this review, we summarize recent studies on EV contents and biological function, focusing on their potential effect in atherosclerosis, including cholesterol metabolism, vascular inflammation, angiogenesis, coagulation and the development of atherosclerotic lesions. EVs may represent potential biomarkers and pharmacological targets for atherosclerotic diseases.

Roles of Exosomes Derived From Immune Cells in Cardiovascular Diseases

Therapies aimed at minimizing adverse remodeling in cardiovascular diseases on a molecular and cellular basis are urgently needed. Exosomes are nanosized lipid vesicles released from various cells that are able to mediate intercellular signaling and communication via their cargos. It has been increasingly demonstrated that exosomes from cardiomyocytes or stem/progenitor cells can promote cardiac repair and regeneration, but their mechanism has not been fully explained. Immune responses mediated by immune cells also play important and complicated roles in the progression of various cardiovascular diseases such as myocardial infarction and atherosclerosis. Exosomes derived from immune cells have shown pleiotropic effects on these pathological states, whether similar to or different from their parent cells. However, the underlying mechanism remains obscure. In this review, we first describe the biological characteristics and biogenesis of exosomes. Then we critically examine the emerging roles of exosomes in cardiovascular disease; the exosomes we focus on are derived from immune cells such as dendritic cells, macrophages, B cells, T cells, as well as neutrophils and mast cells. Among the cardiovascular diseases we discuss, we mainly focus on myocardial infarction and atherosclerosis. As active intercellular communicators, exosomes from immune cells may offer prospective diagnostic and therapeutic value in cardiovascular disease.

Organ and tissue fibrosis: Molecular signals, cellular mechanisms and translational implications

Fibrosis denotes excessive scarring, which exceeds the normal wound healing response to injury in many tissues. Although the extracellular matrix deposition appears unstructured disrupting the normal tissue architecture and subsequently impairing proper organ function, fibrogenesis is a highly orchestrated process determined by defined sequences of molecular signals and cellular response mechanisms. Persistent injury and parenchymal cell death provokes tissue inflammation, macrophage activation and immune cell infiltration. The release of biologically highly active soluble mediators (alarmins, cytokines, chemokines) lead to the local activation of collagen producing mesenchymal cells such as pericytes, myofibroblasts or Gli1 positive mesenchymal stem cell-like cells, to a transition of various cell types into myofibroblasts as well as to the recruitment of fibroblast precursors. Clinical observations and experimental models highlighted that fibrosis is not a one-way road. Specific mechanistic principles of fibrosis regression involve the resolution of chronic tissue injury, the shift of inflammatory processes towards recovery, deactivation of myofibroblasts and finally fibrolysis of excess matrix scaffold. The thorough understanding of common principles of fibrogenic molecular signals and cellular mechanisms in various organs - such as liver, kidney, lung, heart or skin - is the basis for developing improved diagnostics including biomarkers or imaging techniques and novel antifibrotic therapeutics.

Biophysical properties of extracellular vesicles in diagnostics

Extracellular vesicles (EVs) are cell-derived nanoparticles, involved in cell-to-cell communication, in both normal and pathological processes. Originating by the outward budding of the plasma membrane or released by exocytosis, they are natural cargoes for lipids, carbohydrates, proteins and nucleic acids. EV-based diagnostics promises unique advantages compared with conventional strategies involving whole body fluid analysis, including the reduction of biofluids complexity and more specific and sensitive detection of low abundance biomacromolecules. Besides EV cargoes, new breakthrough technologies are addressing EV 'colloidal properties' - including particle content, size and membrane mechanical properties - directly experienced by researchers to be critical factors in biomarkers discovery. This article focuses on the progresses in EV biophysical properties characterization as diagnostic tools for different pathological conditions.