Monocyte derived microvesicles deliver a cell death message via encapsulated caspase-1

The Role of Extracellular Vesicles and Microparticles in Central Nervous System Disorders: Mechanisms, Biomarkers, and Therapeutic Potential

Microscopic, membranous vesicles known as extracellular vesicles (EVs) have been proposed to play a role in the mechanisms underlying central nervous system (CNS) diseases. EVs are secreted by a variety of cells, including myeloid, endothelial, microglial, oligodendroglial, and mesenchymal stem cells (MSCs). Body fluids such as plasma, urine, and cerebrospinal fluid (CSF) contain microparticles (MPs). The detection of MPs in CSF may indicate genetic or environmental susceptibility to conditions such as schizophrenia, schizoaffective disorder, and bipolar disorder. MPs of different origins can exhibit changes in specific biomarkers at various stages of the disease, aiding in the diagnosis and monitoring of neurological conditions. However, understanding the role and clinical applications of MPs is complicated by challenges such as their isolation and dual roles within the CNS. In this review, we discuss the history, characteristics, and roles of MPs in CNS diseases. We also provide practical insights for future research and highlight the challenges that obscure the therapeutic potential of MPs.

Exosome Cargo in Neurodegenerative Diseases: Leveraging Their Intercellular Communication Capabilities for Biomarker Discovery and Therapeutic Delivery

The inexorable progression of neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis, is closely related to irreversible brain decline. Accurately characterizing pathophysiological features and identifying reliable biomarkers for early diagnosis and optimized treatment are critical. Hindered by the blood-brain barrier (BBB), obtaining sensitive monitoring indicators for disease progression and achieving efficient drug delivery remain significant challenges. Exosomes, endogenous nanoscale vesicles that carry key bioactive substances, reflect the intracellular environment and play an important role in cell signaling. They have shown promise in traversing the BBB, serving dual roles as potential biomarkers for NDs and vehicles for targeted drug delivery. However, the specific mechanisms by which exosome influence NDs are not fully understood, necessitating further investigation into their attributes and functionalities in the context of NDs. This review explores how exosomes mediate multifaceted interactions, particularly in exacerbating pathogenic processes such as oxidative stress, neuronal dysfunction, and apoptosis integral to NDs. It provides a comprehensive analysis of the profound impact of exosomes under stress and disease states, assessing their prospective utility as biomarkers and drug delivery vectors, offering new perspectives for tackling these challenging diseases.

Exosomes in multiple sclerosis and Alzheimer's disease - Adversary and ally

Neuroinflammation and the resulting neurodegeneration is a big challenge for the healthcare system, especially with the aging population. Neuroinflammation can result from a variety of insults to the central nervous system leading to an interplay between immune and brain cells that sustains chronic inflammation and injures neural cells. One facilitator of this toxic interplay are exosomes. Exosomes are nano-sized, bilayer lipid vesicles secreted by cells containing proteins, nucleic acids and lipids. Because exosomes can be internalized by other cells, their contents can elicit inflammatory responses and trigger toxicities in recipient cells. On the flip side, exosomes can act as therapeutic vehicles carrying protective cargo to maintain homeostasis. This review discusses exosome biogenesis, composition, and its role in neuroinflammation and neurodegeneration in the context of multiple sclerosis and Alzheimer's disease. The emerging roles of exosomes as biomarkers of neurologic diseases and as therapeutic delivery vehicles are also discussed. With all of these varying roles, interest and excitement in exosomes continue to grow exponentially and their promise as brain therapeutics is only beginning to be explored and harnessed.

Extracellular Vesicles as Mediators in Atherosclerotic Cardiovascular Disease

Atherosclerosis is a chronic inflammatory disease of the arterial intima, characterized by accumulation of lipoproteins and accompanying inflammation, leading to the formation of plaques that eventually trigger occlusive thrombotic events, such as myocardial infarction and ischemic stroke. Although many aspects of plaque development have been elucidated, the role of extracellular vesicles (EVs), which are lipid bilayer-delimited vesicles released by cells as mediators of intercellular communication, has only recently come into focus of atherosclerosis research. EVs comprise several subtypes that may be differentiated by their size, mode of biogenesis, or surface marker expression and cargo. The functional effects of EVs in atherosclerosis depend on their cellular origin and the specific pathophysiological context. EVs have been suggested to play a role in all stages of plaque formation. In this review, we highlight the known mechanisms by which EVs modulate atherogenesis and outline current limitations and challenges in the field.

Unveiling the role of exosomes as cellular messengers in neurodegenerative diseases and their potential therapeutic implications

Exosomes are a subgroup of extracellular vesicles that function as transmitters, allowing cells to communicate more effectively with each other. However, exosomes may have both beneficial and harmful impacts on central nervous system disorders. Hence, the fundamental molecular mechanisms of the origin of illness and its progression are currently being investigated. The involvement of exosomes in the origin and propagation of neurodegenerative illness has been demonstrated recently. Exosomes provide a representation of the intracellular environment since they include various essential bioactive chemicals. The latest studies have demonstrated that exosomes transport several proteins. Additionally, these physiological vesicles are important in the regeneration of nervous tissue and the healing of neuronal lesions. They also offer a microenvironment to stimulate the conformational variation of concerning proteins for aggregation, resulting in neurodegenerative diseases. The biosynthesis, composition, and significance of exosomes as extracellular biomarkers in neurodegenerative disorders are discussed in this article, with a particular emphasis on their neuroprotective effects.

Extracellular Vesicles in Multiple Sclerosis: Their Significance in the Development and Possible Applications as Therapeutic Agents and Biomarkers

Extracellular vesicles (EVs) are "micro-shuttles" that play a role as mediators of intercellular communication. Cells release EVs into the extracellular environment in both physiological and pathological conditions and are involved in intercellular communication, due to their ability to transfer proteins, lipids, and nucleic acids, and in the modulation of the immune system and neuroinflammation. Because EVs can penetrate the blood-brain barrier and move from the central nervous system to the peripheral circulation, and vice versa, recent studies have shown a substantial role for EVs in several neurological diseases, including multiple sclerosis (MS). MS is a demyelinating disease where the main event is caused by T and B cells triggering an autoimmune reaction against myelin constituents. Recent research has elucidate the potential involvement of extracellular vesicles (EVs) in the pathophysiology of MS, although, to date, their potential role both as agents and therapeutic targets in MS is not fully defined. We present in this review a summary and comprehensive examination of EVs' involvement in the pathophysiology of multiple sclerosis, exploring their potential applications as biomarkers and indicators of therapy response.

A guide to the expanding field of extracellular vesicles and their release in regulated cell death programs

Homeostasis disruption is visible at the molecular and cellular levels and may often lead to cell death. This vital process allows us to maintain the more extensive system's integrity by keeping the different features (genetic, metabolic, physiologic, and individual) intact. Interestingly, while cells can die in different manners, dying cells still communicate with their environment. This communication was, for a long time, perceived as only driven by the release of soluble factors. However, it has now been reconsidered with the increasing interest in extracellular vesicles (EVs), which are discovered to be released during different regulated cell death programs, with the observation of specific effects. EVs are game changers in the paradigm of cell-cell communication with tremendous implications in fundamental research with regard to noncell autonomous functions, as well as in biomarkers research, all of which are geared toward diagnostic and therapeutic purposes. This review is composed of two main parts. The first is a comprehensive presentation of the state of the art of the EV field at large. In the second part, we focus on EVs discovered to be released during different regulated cell death programs, also known as cell death EVs (cdEVs), and EV-associated specific effects on recipient cells in the context of cell death and inflammation/inflammatory responses.

Extracellular vesicles in venous thromboembolism and pulmonary hypertension

Venous thromboembolism (VTE) is a multifactorial disease, and pulmonary hypertension (PH) is a serious condition characterized by pulmonary vascular remodeling leading with increased pulmonary vascular resistance, ultimately leading to right heart failure and death. Although VTE and PH have distinct primary etiologies, they share some pathophysiologic similarities such as dysfunctional vasculature and thrombosis. In both conditions there is solid evidence that EVs derived from a variety of cell types including platelets, monocytes, endothelial cells and smooth muscle cells contribute to vascular endothelial dysfunction, inflammation, thrombosis, cellular activation and communications. However, the roles and importance of EVs substantially differ between studies depending on experimental conditions and parent cell origins of EVs that modify the nature of their cargo. Numerous studies have confirmed that EVs contribute to the pathophysiology of VTE and PH and increased levels of various EVs in relation with the severity of VTE and PH, confirming its potential pathophysiological role and its utility as a biomarker of disease severity and as potential therapeutic targets.

A Coxsackievirus B1-mediated nonlytic Extracellular Vesicle-to-cell mechanism of virus transmission and its possible control through modulation of EV release

Like most non-enveloped viruses, CVB1 mainly uses cell lysis to spread. Details of a nonlytic virus transmission remain unclear. Extracellular Vesicles (EVs) transfer biomolecules between cells. We show that CVB1 entry into HeLa cells results in apoptosis and release of CVB1-induced 'medium-sized' EVs (CVB1i-mEVs). These mEVs (100-300 nm) harbour CVB1 as shown by immunoblotting with anti-CVB1-antibody; viral capsids were detected by transmission electron microscopy and RT-PCR revealed CVB1 RNA. The percentage of mEVs released from CVB1-infected HeLa cells harbouring virus was estimated from TEM at 34 %. Inhibition of CVB1i-mEV production, with calpeptin or siRNA knockdown of CAPNS1 in HeLa cells limited spread of CVB1 suggesting these vesicles disseminate CVB1 virions to new host cells by a nonlytic EV-to-cell mechanism. This was confirmed by detecting CVB1 virions inside HeLa cells after co-culture with CVB1i-mEVs; EV release may also prevent apoptosis of infected cells whilst spreading apoptosis to secondary sites of infection.

Engineered extracellular vesicles-like biomimetic nanoparticles as an emerging platform for targeted cancer therapy

Nanotechnology offers the possibility of revolutionizing cancer theranostics in the new era of precision oncology. Extracellular vesicles (EVs)-like biomimetic nanoparticles (EBPs) have recently emerged as a promising platform for targeted cancer drug delivery. Compared with conventional synthetic vehicles, EBPs have several advantages, such as lower immunogenicity, longer circulation time, and better targeting capability. Studies on EBPs as cancer therapeutics are rapidly progressing from in vitro experiments to in vivo animal models and early-stage clinical trials. Here, we describe engineering strategies to further improve EBPs as effective anticancer drug carriers, including genetic manipulation of original cells, fusion with synthetic nanomaterials, and direct modification of EVs. These engineering approaches can improve the anticancer performance of EBPs, especially in terms of tumor targeting effectiveness, stealth property, drug loading capacity, and integration with other therapeutic modalities. Finally, the current obstacles and future perspectives of engineered EBPs as the next-generation delivery platform for anticancer drugs are discussed.

Extracellular vesicles as biomarkers and modulators of atherosclerosis pathogenesis

Extracellular vesicles (EVs) are small, lipid bilayer-enclosed structures released by various cell types that play a critical role in intercellular communication. In atherosclerosis, EVs have been implicated in multiple pathophysiological processes, including endothelial dysfunction, inflammation, and thrombosis. This review provides an up-to-date overview of our current understanding of the roles of EVs in atherosclerosis, emphasizing their potential as diagnostic biomarkers and their roles in disease pathogenesis. We discuss the different types of EVs involved in atherosclerosis, the diverse cargoes they carry, their mechanisms of action, and the various methods employed for their isolation and analysis. Moreover, we underscore the importance of using relevant animal models and human samples to elucidate the role of EVs in disease pathogenesis. Overall, this review consolidates our current knowledge of EVs in atherosclerosis and highlights their potential as promising targets for disease diagnosis and therapy.

Caspases help to spread the message via extracellular vesicles

Cell-cell communication is an essential aspect of multicellular life, key for coordinating cell proliferation, growth, and death in response to environmental changes. Whilst caspases are well-known for facilitating apoptotic and pyroptotic cell death, several recent investigations are uncovering new roles for these enzymes in biological scenarios requiring long-range intercellular signalling mediated by extracellular vesicles (EVs). EVs are small membrane-bound nanoparticles released from cells that may carry and deliver cargo between distant cells, thus helping to coordinate their behaviour. Intriguingly, there is emerging evidence indicating a key contribution of caspases in the biogenesis of EVs, the selection of their cargo content, and EV uptake/function in recipient cells. Here, we discuss the latest findings supporting the interplay between caspases and EVs, and the biological relevance of this molecular convergence for cellular signalling, principally in non-apoptotic scenarios.

Regulation of Mesenchymal Cell Fate by Transfer of Active Gasdermin-D via Monocyte-Derived Extracellular Vesicles

Fibrosis is characterized by inappropriately persistent myofibroblast accumulation and excessive extracellular matrix deposition with the disruption of tissue architecture and organ dysfunction. Regulated death of reparative mesenchymal cells is critical for normal wound repair, but profibrotic signaling promotes myofibroblast resistance to apoptotic stimuli. A complex interplay between immune cells and structural cells underlies lung fibrogenesis. However, there is a paucity of knowledge on how these cell populations interact to orchestrate physiologic and pathologic repair of the injured lung. In this context, gasdermin-D (GsdmD) is a cytoplasmic protein that is activated following cleavage by inflammatory caspases and induces regulated cell death by forming pores in cell membranes. This study was undertaken to evaluate the impact of human (Thp-1) monocyte-derived extracellular vesicles and GsdmD on human lung fibroblast death. Our data show that active GsdmD delivered by monocyte-derived extracellular vesicles induces caspase-independent fibroblast and myofibroblast death. This cell death was partly mediated by GsdmD-independent induction of cellular inhibitor of apoptosis 2 (cIAP-2) in the recipient fibroblast population. Our findings, to our knowledge, define a novel paradigm by which inflammatory monocytes may orchestrate the death of mesenchymal cells in physiologic wound healing, illustrating the potential to leverage this mechanism to eliminate mesenchymal cells and facilitate the resolution of fibrotic repair.

Extracellular vesicles as contributors in the pathogenesis of multiple sclerosis

Extracellular vesicles (EVs) are a heterogeneous family of extracellular structures bounded by a phospholipid bilayer, released by all cell types in various biological fluids, such as blood and cerebrospinal fluid (CSF), playing important roles in intercellular communication, both locally and systemically. EVs carry and deliver a variety of bioactive molecules (proteins, nucleic acids, lipids and metabolites), conferring epigenetic and phenotypic changes to the recipient cells and thus resulting as important mediators of both homeostasis and pathogenesis. In neurological diseases, such as multiple sclerosis (MS), the EV ability to cross Blood-Brain Barrier (BBB), moving from central nervous system (CNS) to the peripheral circulation and vice versa, has increased the interest in EV study in the neurological field. In the present review, we will provide an overview of the recent advances made in understanding the pathogenic role of EVs regarding the immune response, the BBB dysfunction and the CNS inflammatory processes.

Extracellular Vesicles and Vascular Inflammation

Vascular inflammation is the most common pathological feature in the pathogenesis of human disease. It is a complex immune process involved with many different types of cells including platelet, monocytes, macrophages, endothelial cells, and others. It is widely accepted that both innate and adaptive immune responses are important for the initiation and progression of vascular inflammation. The cell-cell interaction constitutes an important aspect of those immune responses in the vascular inflammation. Extracellular vesicles (EVs) are nanometer-sized double-layer lipid membrane vesicles released from most types of cells. They have been proved to play critical roles in intercellular communication in the occurrence and development of multisystem diseases. With the advancement of basal medical science, the biological roles of EVs in vascular inflammation have been clearer today. In this chapter, we will summarize the advance progress of extracellular vesicles in regulating vascular inflammation and its potential application in the clinical.

Extracellular Vesicles Derived from Mesenchymal Stem Cells: A Potential Biodrug for Acute Respiratory Distress Syndrome Treatment

Acute respiratory distress syndrome (ARDS) is a severe respiratory disease associated with high morbidity and mortality in the clinic. In the face of limited treatment options for ARDS, extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have recently shown promise. They regulate levels of growth factors, cytokines, and other internal therapeutic molecules. The possible therapeutic mechanisms of MSC-EVs include anti-inflammatory, cell injury repair, alveolar fluid clearance, and microbe clearance. The potent therapeutic ability and biocompatibility of MSC-EVs have enabled them as an alternative option to ameliorate ARDS. In this review, recent advances, therapeutic mechanisms, advantages and limitations, as well as improvements of using MSC-EVs to treat ARDS are summarized. This review is expected to provide a brief view of the potential applications of MSC-EVs as novel biodrugs to treat ARDS.

Translating extracellular vesicle packaging into therapeutic applications

Extracellular vesicles (EVs) are membrane-bound particles released by cells in various (patho)physiological conditions. EVs can transfer effector molecules and elicit potent responses in recipient cells, making them attractive therapeutic agents and drug delivery platforms. In contrast to their tremendous potential, only a few EV-based therapies and drug delivery have been approved for clinical use, which is largely attributed to limited therapeutic loading technologies and efficiency. As EV cargo has major influence on their functionality, understanding and translating the biology underlying the packaging and transferring of biomolecule cargos (e.g. miRNAs, pathogen antigens, small molecule drugs) into EVs is key in harnessing their therapeutic potential. In this review, through recent insights into EVs’ content packaging, we discuss different mechanisms utilized by EVs during cargo packaging, and how one might therapeutically exploit this process. Apart from the well-characterized EVs like exosomes and microvesicles, we also cover the less-studied and other EV subtypes like apoptotic bodies, large oncosomes, bacterial outer membrane vesicles, and migrasomes to highlight therapeutically-diverse opportunities of EV armoury.

Blood Cell-Derived Microvesicles in Hematological Diseases and beyond

Microvesicles or ectosomes represent a major type of extracellular vesicles that are formed by outward budding of the plasma membrane. Typically, they are bigger than exosomes but smaller than apoptotic vesicles, although they may overlap with both in size and content. Their release by cells is a means to dispose redundant, damaged, or dangerous material; to repair membrane lesions; and, primarily, to mediate intercellular communication. By participating in these vital activities, microvesicles may impact a wide array of cell processes and, consequently, changes in their concentration or components have been associated with several pathologies. Of note, microvesicles released by leukocytes, red blood cells, and platelets, which constitute the vast majority of plasma microvesicles, change under a plethora of diseases affecting not only the hematological, but also the nervous, cardiovascular, and urinary systems, among others. In fact, there is evidence that microvesicles released by blood cells are significant contributors towards pathophysiological states, having inflammatory and/or coagulation and/or immunomodulatory arms, by either promoting or inhibiting the relative disease phenotypes. Consequently, even though microvesicles are typically considered to have adverse links with disease prognosis, progression, or outcomes, not infrequently, they exert protective roles in the affected cells. Based on these functional relations, microvesicles might represent promising disease biomarkers with diagnostic, monitoring, and therapeutic applications, equally to the more thoroughly studied exosomes. In the current review, we provide a summary of the features of microvesicles released by blood cells and their potential implication in hematological and non-hematological diseases.

Extracellular Vesicles as Drivers of Immunoinflammation in Atherothrombosis

Atherosclerotic cardiovascular disease is the leading cause of morbidity and mortality all over the world. Extracellular vesicles (EVs), small lipid-bilayer membrane vesicles released by most cellular types, exert pivotal and multifaceted roles in physiology and disease. Emerging evidence emphasizes the importance of EVs in intercellular communication processes with key effects on cell survival, endothelial homeostasis, inflammation, neoangiogenesis, and thrombosis. This review focuses on EVs as effective signaling molecules able to both derail vascular homeostasis and induce vascular dysfunction, inflammation, plaque progression, and thrombus formation as well as drive anti-inflammation, vascular repair, and atheroprotection. We provide a comprehensive and updated summary of the role of EVs in the development or regression of atherosclerotic lesions, highlighting the link between thrombosis and inflammation. Importantly, we also critically describe their potential clinical use as disease biomarkers or therapeutic agents in atherothrombosis.

Lipidomic Profiling of Bronchoalveolar Lavage Fluid Extracellular Vesicles Indicates Their Involvement in Lipopolysaccharide-Induced Acute Lung Injury

Emerging data support the pivotal role of extracellular vesicles (EVs) in normal cellular physiology and disease conditions. However, despite their abundance, there is much less information about the lipid mediators carried in EVs, especially in the context of acute lung injury (ALI). Our data demonstrate that C57BL/6 mice subjected to intranasal Escherichia coli lipopolysaccharide (LPS)-induced ALI release, a higher number of EVs into the alveolar space, compared to saline-treated controls. EVs released during ALI originated from alveolar epithelial cells, macrophages, and neutrophils and carry a diverse array of lipid mediators derived from ω-3 and ω-6 polyunsaturated fatty acids (PUFA). The eicosanoids in EVs correlated with cellular levels of arachidonic acid, expression of cytosolic phospholipase A2, cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome epoxygenase p450 proteins in pulmonary macrophages. Furthermore, EVs from LPS-toll-like receptor 4 knockout (TLR4-/-) mice contained significantly lower amounts of COX and LOX catalyzed eicosanoids and ω-3 PUFA metabolites. More importantly, EVs from LPS-treated wild-type mice increased TNF-α release by macrophages and reduced alveolar epithelial monolayer barrier integrity compared to EVs from LPS-treated TLR4-/- mice. In summary, our study demonstrates for the first time that the EV carried PUFA metabolite profile in part depends on the inflammatory status of the lung macrophages and modulates pulmonary macrophage and alveolar epithelial cell function during LPS-induced ALI.

Extracellular Vesicles as Central Mediators of COPD Pathophysiology

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, smoking-related disease of significant global impact. The complex biology of COPD is ultimately driven by a few interrelated processes, including proteolytic tissue remodeling, innate immune inflammation, derangements of the host-pathogen response, aberrant cellular phenotype switching, and cellular senescence, among others. Each of these processes are engendered and perpetuated by cells modulating their environment or each other. Extracellular vesicles (EVs) are powerful effectors that allow cells to perform a diverse array of functions on both adjacent and distant tissues, and their pleiotropic nature is only beginning to be appreciated. As such, EVs are candidates to play major roles in these fundamental mechanisms of disease behind COPD. Furthermore, some such roles for EVs are already established, and EVs are implicated in significant aspects of COPD pathogenesis. Here, we discuss known and potential ways that EVs modulate the environment of their originating cells to contribute to the processes that underlie COPD.

Cochlear Immune Response in Presbyacusis: a Focus on Dysregulation of Macrophage Activity

Age-related hearing loss, or presbyacusis, is a prominent chronic degenerative disorder that affects many older people. Based on presbyacusis pathology, the degeneration occurs in both sensory and non-sensory cells, along with changes in the cochlear microenvironment. The progression of age-related neurodegenerative diseases is associated with an altered microenvironment that reflects chronic inflammatory signaling. Under these conditions, resident and recruited immune cells, such as microglia/macrophages, have aberrant activity that contributes to chronic neuroinflammation and neural cell degeneration. Recently, researchers identified and characterized macrophages in human cochleae (including those from older donors). Along with the age-related changes in cochlear macrophages in animal models, these studies revealed that macrophages, an underappreciated group of immune cells, may play a critical role in maintaining the functional integrity of the cochlea. Although several studies deciphered the molecular mechanisms that regulate microglia/macrophage dysfunction in multiple neurodegenerative diseases, limited studies have assessed the mechanisms underlying macrophage dysfunction in aged cochleae. In this review, we highlight the age-related changes in cochlear macrophage activities in mouse and human temporal bones. We focus on how complement dysregulation and the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 inflammasome could affect macrophage activity in the aged peripheral auditory system. By understanding the molecular mechanisms that underlie these regulatory systems, we may uncover therapeutic strategies to treat presbyacusis and other forms of sensorineural hearing loss.

Transverse aortic constriction-induced heart failure leads to increased levels of circulating microparticles

BACKGROUND

Circulating microparticles represent one type of signal transmission between cells. Previous studies revealed increased levels of circulating microparticles in patients with heart failure, while composition, temporal occurrence and biological effects are largely unknown.

METHODS

Circulating microparticles were quantified by flow cytometry in mice following TAC. Microparticles were characterized by NTA and immunoblotting for Flotillin-1. Microparticle content was investigated by microRNA analyses.

RESULTS

After TAC induction of heart failure could be demonstrated. Simultaneously we observed increased numbers of circulating microparticles in the first week after TAC with a rapid decline thereafter. The most relevant fraction of circulating EVs after TAC derived from lymphocytes containing has-miR-26a-5p and / -146b-5p known to be involved in inflammatory processes.

CONCLUSION

This work provides a previously unknown timely limited occurrence of circulating microparticles after new onset of heart failure which might have important influence on disease development and progression and thereby are of probable therapeutic relevance.

Targeting regulated cell death in aortic aneurysm and dissection therapy

Regulated cell death (RCD) is a basic biological phenomenon associated with cell and tissue homeostasis. Recent studies have enriched our understanding of RCD, and many novel cell death types, such as ferroptosis and pyroptosis, have been discovered and defined. Aortic aneurysm and dissection (AAD) is a life-threatening condition, but the pathogenesis remains largely unclear. A series of studies have indicated that the death of smooth muscle cells, endothelial cells and inflammatory cells participates in the development of AAD and that corresponding interventions could alleviate disease progression. Many treatments against cell death have been used to impede the process of AAD in vitro and in vivo, which provides strategies to protect against this condition. In this review, we focus on various types of regulated cell death and provide a framework of their roles in AAD, and the information contributes to further exploration of the molecular mechanisms of AAD.

[Extracellular vesicles and cardiovascular diseases]

Cardiovascular diseases remain the leading cause of death globally. There is therefore a need to develop new approaches for the treatment and early detection of these ailments. In the past decades, extracellular vesicles (EVs) have attracted significant attention as their role in intercellular communication has been brought to light. They have been shown to regulate pathways such as cellular inflammation or angiogenesis, and are therefore involved in key aspects of cardiovascular pathophysiology. Interestingly, EVs appear to have a multifaceted role which depends on their origin and cargo. Though at times deleterious, they have also been proposed as promising diagnostic tools and potential therapeutics. This review highlights recent advances in the role of extracellular vesicles in cardiovascular pathologies.

Role of extracellular vesicles in atherosclerosis: An update

Extracellular vesicles (EVs) are membrane particles released by most cell types in response to different stimuli. They are composed of a lipid bilayer that encloses a wide range of bioactive material, including proteins and nucleic acids. EVs have garnered increasing attention over recent years, as their role in intercellular communication has been brought to light. As such, they have been found to regulate pathophysiologic pathways like inflammation, angiogenesis, or senescence, and are therefore implicated in key aspects atherosclerosis initiation and progression. Interestingly, EVs appear to have a multifaceted role; depending on their cargo, they can either facilitate or hamper the development of atherosclerotic lesions. In this review, we examine how EVs of varying origins may be implicated in the different phases of atherosclerotic lesion development. We also discuss the need to standardize isolation and analysis procedures to fully fulfil their potential as biomarkers and therapeutics for cardiovascular diseases.

Interest of extracellular vesicles in regards to lipid nanoparticle based systems for intracellular protein delivery

Compared to chemicals that continue to dominate the overall pharmaceutical market, protein therapeutics offer the advantages of higher specificity, greater activity, and reduced toxicity. While nearly all existing therapeutic proteins were developed against soluble or extracellular targets, the ability for proteins to enter cells and target intracellular compartments can significantly broaden their utility for a myriad of exiting targets. Given their physical, chemical, biological instability that could induce adverse effects, and their limited ability to cross cell membranes, delivery systems are required to fully reveal their biological potential. In this context, as natural protein nanocarriers, extracellular vesicles (EVs) hold great promise. Nevertheless, if not present naturally, bringing an interest protein into EV is not an easy task. In this review, we will explore methods used to load extrinsic protein into EVs and compare these natural vectors to their close synthetic counterparts, liposomes/lipid nanoparticles, to induce intracellular protein delivery.

Extracellular Vesicles: A Double-Edged Sword in Sepsis

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to an infection. Several studies on mouse and patient sepsis samples have revealed that the level of extracellular vesicles (EVs) in the blood is altered compared to healthy controls, but the different functions of EVs during sepsis pathology are not yet completely understood. Sepsis EVs are described as modulators of inflammation, lymphocyte apoptosis, coagulation and organ dysfunction. Furthermore, EVs can influence clinical outcome and it is suggested that EVs can predict survival. Both detrimental and beneficial roles for EVs have been described in sepsis, depending on the EV cellular source and the disease phase during which the EVs are studied. In this review, we summarize the current knowledge of EV sources and functions during sepsis pathology based on in vitro and mouse models, as well as patient samples.

Potential Roles of Extracellular Vesicles as Biomarkers and a Novel Treatment Approach in Multiple Sclerosis

Extracellular vesicles (EVs) are a heterogeneous group of bilayer membrane-wrapped molecules that play an important role in cell-to-cell communication, participating in many physiological processes and in the pathogenesis of several diseases, including multiple sclerosis (MS). In recent years, many studies have focused on EVs, with promising results indicating their potential role as biomarkers in MS and helping us better understand the pathogenesis of the disease. Recent evidence suggests that there are novel subpopulations of EVs according to cell origin, with those derived from cells belonging to the nervous and immune systems providing information regarding inflammation, demyelination, axonal damage, astrocyte and microglia reaction, blood–brain barrier permeability, leukocyte transendothelial migration, and ultimately synaptic loss and neuronal death in MS. These biomarkers can also provide insight into disease activity and progression and can differentiate patients’ disease phenotype. This information can enable new pathways for therapeutic target discovery, and consequently the development of novel treatments. Recent evidence also suggests that current disease modifying treatments (DMTs) for MS modify the levels and content of circulating EVs. EVs might also serve as biomarkers to help monitor the response to DMTs, which could improve medical decisions concerning DMT initiation, choice, escalation, and withdrawal. Furthermore, EVs could act not only as biomarkers but also as treatment for brain repair and immunomodulation in MS. EVs are considered excellent delivery vehicles. Studies in progress show that EVs containing myelin antigens could play a pivotal role in inducing antigen-specific tolerance of autoreactive T cells as a novel strategy for the treatment as “EV-based vaccines” for MS. This review explores the breakthrough role of nervous and immune system cell-derived EVs as markers of pathological disease mechanisms and potential biomarkers of treatment response in MS. In addition, this review explores the novel role of EVs as vehicles for antigen delivery as a therapeutic vaccine to restore immune tolerance in MS autoimmunity.

Extracellular vesicles in atherothrombosis and cardiovascular disease: Friends and foes

Extracellular vesicles (EV, exosomes and microvesicles -MV-) are 30-1000 nm particles surrounded by a phospholipid bilayer membrane that are released from almost all cell types through several pathways. EV encapsulate bioactive molecules, and the molecular cargo is determined by the trigger stimulating its release, reflecting its cell origin and biological functions. This review is primarily focused on the latest evidence of the roles of EV, released from cells involved in the different stages of atherothrombosis. The potential translation of this information to the clinical arena is also discussed. EV can have both pro- and anti-atherothrombotic effects depending on several factors, such as the type of vesicle (MV/exosome), its molecular cargo, its cell of origin, and the context in which are generated, i.e., the stimulus triggering its release. In fact, EV actively participate in every step of atherosclerosis onset and progression, and also in thrombus formation leading to a major adverse cardiovascular event. Moreover, EV have a determinant role in fibrous cap stability, thus determining the propensity of the plaque to rupture. On the other hand, and again, conditioned by the context and stimulus instigating its secretion, some EV may have protective biological functions, perhaps as a compensatory mechanism or even with reparative or regenerative potential. Therefore, the study of the implication of EV in atherothrombosis might be of relevance to unveil new therapeutic targets, vectors and biomarkers of cardiovascular disease (CVD).

Extracellular Vesicles and Citrullinated Histone H3 in Coronavirus Disease 2019 Patients

OBJECTIVES

 Pulmonary thrombus formation is a hallmark of coronavirus disease 2019 (COVID-19). A dysregulated immune response culminating in thromboinflammation has been described, but the pathomechanisms remain unclear.

METHODS

 We studied 41 adult COVID-19 patients with positive results on reverse-transcriptase polymerase-chain-reaction assays and 37 sex- and age-matched healthy controls. Number and surface characteristics of extracellular vesicles (EVs) and citrullinated histone H3 levels were determined in plasma upon inclusion by flow cytometry and immunoassay.

RESULTS

 In total, 20 patients had severe and 21 nonsevere disease. The number of EV (median [25th, 75th percentile]) was significantly higher in patients compared with controls (658.8 [353.2, 876.6] vs. 435.5 [332.5, 585.3], geometric mean ratio [95% confidence intervals]: 2.6 [1.9, 3.6]; p < 0.001). Patients exhibited significantly higher numbers of EVs derived from platelets, endothelial cells, leukocytes, or neutrophils than controls. EVs from alveolar-macrophages and alveolar-epithelial cells were detectable in plasma and were significantly higher in patients. Intercellular adhesion molecule-1-positive EV levels were higher in patients, while no difference between tissue factor-positive and angiotensin-converting enzyme-positive EV was seen between both groups. Levels of EV did not differ between patients with severe and nonsevere COVID-19. Citrullinated histone H3 levels (ng/mL, median [25th, 75th percentile]) were higher in patients than in controls (1.42 [0.6, 3.4] vs. 0.31 [0.1, 0.6], geometric mean ratio: 4.44 [2.6, 7.7]; p < 0.001), and were significantly lower in patients with nonsevere disease compared with those with severe disease.

CONCLUSION

 EV and citrullinated histone H3 are associated with COVID-19 and could provide information regarding pathophysiology of the disease.

Role of ATP in Extracellular Vesicle Biogenesis and Dynamics

Adenosine triphosphate (ATP) is among the molecules involved in the immune response. It acts as danger signal that promotes inflammation by activating both P2X and P2Y purinergic receptors expressed in immune cells, including microglia, and tumor cells. One of the most important receptors implicated in ATP-induced inflammation is P2X7 receptor (P2X7R). The stimulation of P2X7R by high concentration of ATP results in cell proliferation, inflammasome activation and shedding of extracellular vesicles (EVs). EVs are membrane structures released by all cells, which contain a selection of donor cell components, including proteins, lipids, RNA and ATP itself, and are able to transfer these molecules to target cells. ATP stimulation not only promotes EV production from microglia but also influences EV composition and signaling to the environment. In the present review, we will discuss the current knowledge on the role of ATP in the biogenesis and dynamics of EVs, which exert important functions in physiology and pathophysiology.

Emerging Roles of Extracellular Vesicles in the Central Nervous System: Physiology, Pathology, and Therapeutic Perspectives

Extracellular vesicles or EVs are secreted by most, if not all, eukaryote cell types and recaptured by neighboring or distant cells. Their cargo, composed of a vast diversity of proteins, lipids, and nucleic acids, supports the EVs' inter-cellular communication. The role of EVs in many cellular processes is now well documented both in physiological and pathological conditions. In this review, we focus on the role of EVs in the central nervous system (CNS) in physiological as well as pathological conditions such as neurodegenerative diseases or brain cancers. We also discuss the future of EVs in clinical research, in particular, their value as biomarkers as well as innovative therapeutic agents. While an increasing number of studies reveal EV research as a promising field, progress in the standardization of protocols and innovation in analysis as well as in research tools is needed to make a breakthrough in our understanding of their impact in the pathophysiology of the brain.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Lung Diseases: Current Status and Perspectives

Extracellular vesicles (EVs) have emerged as a potential therapy for several diseases. These plasma membrane-derived fragments are released constitutively by virtually all cell types-including mesenchymal stromal cells (MSCs)-under stimulation or following cell-to-cell interaction, which leads to activation or inhibition of distinct signaling pathways. Based on their size, intracellular origin, and secretion pathway, EVs have been grouped into three main populations: exosomes, microvesicles (or microparticles), and apoptotic bodies. Several molecules can be found inside MSC-derived EVs, including proteins, lipids, mRNA, microRNAs, DNAs, as well as organelles that can be transferred to damaged recipient cells, thus contributing to the reparative process and promoting relevant anti-inflammatory/resolutive actions. Indeed, the paracrine/endocrine actions induced by MSC-derived EVs have demonstrated therapeutic potential to mitigate or even reverse tissue damage, thus raising interest in the regenerative medicine field, particularly for lung diseases. In this review, we summarize the main features of EVs and the current understanding of the mechanisms of action of MSC-derived EVs in several lung diseases, such as chronic obstructive pulmonary disease (COPD), pulmonary infections [including coronavirus disease 2019 (COVID-19)], asthma, acute respiratory distress syndrome (ARDS), idiopathic pulmonary fibrosis (IPF), and cystic fibrosis (CF), among others. Finally, we list a number of limitations associated with this therapeutic strategy that must be overcome in order to translate effective EV-based therapies into clinical practice.

Inflammatory Caspases Drive Pyroptosis in Acute Lung Injury

Acute lung injury (ALI), a critical respiratory disorder that causes diffuse alveolar injury leads to high mortality rates with no effective treatment. ALI is characterized by varying degrees of ventilation/perfusion mismatch, severe hypoxemia, and poor pulmonary compliance. The diffuse injury to cells is one of most important pathological characteristics of ALI. Pyroptosis is a form of programmed cell death distinguished from apoptosis induced by inflammatory caspases, which can release inflammatory cytokines to clear cells infected by pathogens and promote monocytes to reassemble at the site of injury. And pyroptosis not only promotes inflammation in certain cell types, but also regulates many downstream pathways to perform different functions. There is increasing evidence that pyroptosis and its related inflammatory caspases play an important role in the development of acute lung injury. The main modes of activation of pyroptosis is not consistent among different types of cells in lung tissue. Meanwhile, inhibition of inflammasome, the key to initiating pyroptosis is currently the main way to treat acute lung injury. The review summarizes the relationship among inflammatory caspases, pyroptosis and acute lung injury and provides general directions and strategies to conduct further research.

Pyroptotic cell-derived microparticle: An atherogenic factor in infectious diseases

Chronic infection is considered a risk factor for atherosclerosis. The link between infectious agents and atherosclerosis is manifested by the presence of infection-induced pyroptotic cells in atherosclerotic lesions. Pyroptosis is an inflammatory form of programmed cell death that occurs most frequently upon infection. However, inflammation is not the only cause by which pyroptosis involved in atherosclerosis. During pyroptosis, a large amount of microparticles are released from pyroptotic cells, which not only transfer inflammatory mediators to arterial vessel, but also mediate the interaction between a variety of cells, leading to endothelial injury, macrophage infiltration, vascular smooth muscle cell migration and proliferation, thereby accelerating atherosclerosis. Thus, we proposed hypothesis that pyroptotic cell-derived microparticle is an atherogenic factor in infectious diseases.

Emerging Role of Extracellular Vesicles in the Pathophysiology of Multiple Sclerosis

Extracellular vesicles (EVs) represent a new reality for many physiological and pathological functions as an alternative mode of intercellular communication. This is due to their capacity to interact with distant recipient cells, usually involving delivery of the EVs contents into the target cells. Intensive investigation has targeted the role of EVs in different pathological conditions, including multiple sclerosis (MS). MS is a chronic inflammatory and neurodegenerative disease of the nervous system, one of the main causes of neurological disability in young adults. The fine interplay between the immune and nervous systems is profoundly altered in this disease, and EVs seems to have a relevant impact on MS pathogenesis. Here, we provide an overview of both clinical and preclinical studies showing that EVs released from blood–brain barrier (BBB) endothelial cells, platelets, leukocytes, myeloid cells, astrocytes, and oligodendrocytes are involved in the pathogenesis of MS and of its rodent model experimental autoimmune encephalomyelitis (EAE). Most of the information points to an impact of EVs on BBB damage, on spreading pro-inflammatory signals, and altering neuronal functions, but EVs reparative function of brain damage deserves attention. Finally, we will describe recent advances about EVs as potential therapeutic targets and tools for therapeutic intervention in MS.

Role of Extracellular Vesicles in Autoimmune Pathogenesis

Autoimmune diseases are conditions that emerge from abnormal immune responses to natural parts of the body. Extracellular vesicles (EVs) are membranous structures found in almost all types of cells. Because EVs often transport “cargo” between cells, their ability to crosstalk may be an important communication pathway within the body. The pathophysiological role of EVs is increasingly recognized in autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, Type 1 diabetes, and autoimmune thyroid disease. EVs are considered as biomarkers of these diseases. This article outlines existing knowledge on the biogenesis of EVs, their role as messegers in cellular communication and the function in T/B cell differentiation and maturation, and focusing on their potential application in autoimmune diseases.

Extracellular vesicle signalling in atherosclerosis

Atherosclerosis is a major cardiovascular disease and in 2016, the World Health Organisation (WHO) estimated 17.5 million global deaths, corresponding to 31% of all global deaths, were driven by inflammation and deposition of lipids into the arterial wall. This leads to the development of plaques which narrow the vessel lumen, particularly in the coronary and carotid arteries. Atherosclerotic plaques can become unstable and rupture, leading to myocardial infarction or stroke. Extracellular vesicles (EVs) are a heterogeneous population of vesicles secreted from cells with a wide range of biological functions. EVs participate in cell-cell communication and signalling via transport of cargo including enzymes, DNA, RNA and microRNA in both physiological and patholophysiological settings. EVs are present in atherosclerotic plaques and have been implicated in cellular signalling processes in atherosclerosis development, including immune responses, inflammation, cell proliferation and migration, cell death and vascular remodeling during progression of the disease. In this review, we summarise the current knowledge regarding EV signalling in atherosclerosis progression and the potential of utilising EV signatures as biomarkers of disease.

Deciphering the messages carried by extracellular vesicles in hematological malignancies

Extracellular vesicles (EVs) are nanosized membrane-bound particles released from all living cells examined thus far. EVs can transfer information in the form of proteins, nucleic acids, and lipids from donor cells to recipient cells. Here we summarize recent advances in understanding the role(s) EVs play in hematological malignancies (HM) and outline potential prognostic and diagnostic strategies using EVs. EVs have been shown to promote proliferation and angiogenesis, and alter the bone marrow microenvironment to favour the growth and survival of diverse HM. They also promote evasion of anti-cancer immune responses and increase multi-drug resistance. Using knowledge of EV biology, including HM-specific packaging of cargo, EV based diagnostics and therapeutic approaches show substantial clinical promise. However, while EVs may represent a new paradigm to solve many of the challenges in treating and/or diagnosing HM, much work is needed before they can be used clinically to improve patient outcomes.

Emerging technologies for profiling extracellular vesicle heterogeneity

Extracellular vesicles (EVs) are membrane-bound vesicles secreted by most cell types and exist in virtually all bodily fluids. They carry on a wealth of proteomic and genetic information including proteins, lipids, miRNAs, mRNA, non-coding RNA and other molecules from parental cells. Increasing evidence shows that within populations of EVs, their biogenesis, physical characteristics (e.g. size, density, morphology) and cargos (e.g. protein, lipid content, nucleic acids) may vary substantially, which accordingly change their biological properties. To fully exploit the potential of EVs, it requires qualified methods to profile EV heterogeneity. In this review, we survey recent approaches for EV isolation with innovative discoveries in heterogeneity. The main challenges in EV heterogeneity research are identified, and the roles of single cell EV profiling and single EV imaging are highlighted. We further discuss promising opportunities for resolving the underlying complexity of EV heterogeneity.

Circulating extracellular vesicles as non-invasive biomarker of rejection in heart transplant

BACKGROUND

Circulating extracellular vesicles (EVs) are raising considerable interest as a non-invasive diagnostic tool, as they are easily detectable in biologic fluids and contain a specific set of nucleic acids, proteins, and lipids reflecting pathophysiologic conditions. We aimed to investigate differences in plasma-derived EV surface protein profiles as a biomarker to be used in combination with endomyocardial biopsies (EMBs) for the diagnosis of allograft rejection.

METHODS

Plasma was collected from 90 patients (53 training cohort, 37 validation cohort) before EMB. EV concentration was assessed by nanoparticle tracking analysis. EV surface antigens were measured using a multiplex flow cytometry assay composed of 37 fluorescently labeled capture bead populations coated with specific antibodies directed against respective EV surface epitopes.

RESULTS

The concentration of EVs was significantly increased and their diameter decreased in patients undergoing rejection as compared with negative ones. The trend was highly significant for both antibody-mediated rejection and acute cellular rejection (p < 0.001). Among EV surface markers, CD3, CD2, ROR1, SSEA-4, human leukocyte antigen (HLA)-I, and CD41b were identified as discriminants between controls and acute cellular rejection, whereas HLA-II, CD326, CD19, CD25, CD20, ROR1, SSEA-4, HLA-I, and CD41b discriminated controls from patients with antibody-mediated rejection. Receiver operating characteristics curves confirmed a reliable diagnostic performance for each single marker (area under the curve range, 0.727-0.939). According to differential EV-marker expression, a diagnostic model was built and validated in an external cohort of patients. Our model was able to distinguish patients undergoing rejection from those without rejection. The accuracy at validation in an independent external cohort reached 86.5%. Its application for patient management has the potential to reduce the number of EMBs. Further studies in a higher number of patients are required to validate this approach for clinical purposes.

CONCLUSIONS

Circulating EVs are highly promising as a new tool to characterize cardiac allograft rejection and to be complementary to EMB monitoring.

Induction of ASC pyroptosis requires gasdermin D or caspase-1/11-dependent mediators and IFNβ from pyroptotic macrophages

Mesenchymal stem cells (MSCs) have been used in cell-based therapies for a variety of disorders. Some factors such as inflammatory mediators in the diseased area might damage the survival of MSCs and affect their efficacy. Pyroptosis is a form of programmed necrosis as a response for immune cells to cytosolic pathogenic stimuli. Whether MSCs develop pyroptosis under pathological stimulation, its underlying mechanism and biological significance are still unclear. Here, we found that LPS, flagellin, dsDNA, nigericin (NIG), or LPS combined with nigericin (LPS/NIG) could not induce pyroptosis in adipose-tissue-derived mesenchymal stem cells (ASCs). However, when applied the culture media collected from LPS/NIG-induced pyroptotic bone marrow-derived macrophages (BMDMs) to incubate ASCs, ASCs developed pyroptosis. Inhibition of caspases or deletion of Caspase-1/11 in ASCs did not affect the pyroptotic macrophage media-triggered ASC pyroptosis while ablation of Caspase-1/11 abolished BMDM pyroptosis induced by LPS/NIG. Media collected from LPS/NIG stimulated Gsdmd^−/− or Caspase-1/11^−/− BMDMs could not induce pyroptosis of ASCs. In addition, RNA-seq analysis showed that interferon (IFN)-stimulated genes were upregulated in pyroptotic ASCs. Adding IFNβ could boost LPS/NIG stimulated BMDM media-induced ASC pyroptosis. Surprisingly, the pyroptotic ASCs had a lower bactericidal ability to P. Aeruginosa. Taken together, induction of ASC pyroptosis requires gasdermin D or caspase-1/11-dependent mediators and IFNβ from pyroptotic macrophages.

Chicken-or-egg question: Which came first, extracellular vesicles or autoimmune diseases?

Extracellular vesicles (EVs) have attracted great interest as contributors to autoimmune disease (AD) pathogenesis, owing to their immunomodulatory potential; they may also play a role in triggering tolerance disruption, by delivering auto‐antigens. EVs are released by almost all cell types, and afford paracrine or distal cell communication, functioning as biological carriers of active molecules including lipids, proteins, and nucleic acids. Depending on stimuli from the external microenvironment or on their cargo, EVs can promote or suppress immune responses. ADs are triggered by inappropriate immune‐system activation against the self, but their precise etiology is still poorly understood. Accumulating evidence indicates that lifestyle and diet have a strong impact on their clinical onset and development. However, to date the mechanisms underlying AD pathogenesis are not fully clarified, and reliable markers, which would provide early prediction and disease progression monitoring, are lacking. In this connection, EVs have recently been indicated as a promising source of AD biomarkers. Although EV isolation is currently based on differential centrifugation or density‐gradient ultracentrifugation, the resulting co‐isolation of contaminants (i.e., protein aggregates), and the pooling of all EVs in one sample, limit this approach to abundantly‐expressed EVs. Flow cytometry is one of the most promising methods for detecting EVs as biomarkers, and may have diagnostic applications. Furthermore, very recent findings describe a new method for identifying and sorting EVs by flow cytometry from freshly collected body fluids, based on specific EV surface markers.

The Contrasting Role of Extracellular Vesicles in Vascular Inflammation and Tissue Repair

Extracellular vesicles are a heterogeneous family of vesicles, generated from different subcellular compartments and released into the extracellular space. Composed of a lipid bilayer encompassing both soluble cytosolic material and nuclear components, these organelles have been recently described as novel regulators of intercellular communication between adjacent and remote cells. Due to their diversified composition and biological content, they portray specific signatures of cellular activation and pathological processes, their potential as diagnostic and prognostic biomarkers has raised significant interest in cardiovascular diseases. Circulating vesicles, especially those released from platelets, leukocytes, and endothelial cells are found to play a critical role in activating several fundamental cells within the vasculature, including endothelial cells and vascular smooth muscle cells. Their intrinsic activity and immunomodulatory properties lends them to not only promote vascular inflammation, but also enhance tissue regeneration, vascular repair, and indeed resolution. In this review we aim to recapitulate the recent findings concerning the roles played by EVs that originate from different circulating cells, with particular reference to their action on the endothelium. We focus herein, on the interaction of platelet and leukocyte EVs with the endothelium. In addition, their potential biological function in promoting tissue resolution and vascular repair will also be discussed.

Chemotherapeutic drugs stimulate the release and recycling of extracellular vesicles to assist cancer cells in developing an urgent chemoresistance

Background

Chemotherapy is a widely used treatment for cancer. However, the development of acquired multidrug resistance (MDR) is a serious issue. Emerging evidence has shown that the extracellular vesicles (EVs) mediate MDR, but the underlying mechanism remains unclear, especially the effects of chemotherapeutic agents on this process.

Methods

Extracellular vesicles isolation was performed by differential centrifugation. The recipient cells that acquired ATP-binding cassette sub-family B member 1 (ABCB1) proteins were sorted out from co-cultures according to a stringent multi-parameter gating strategy by fluorescence-activated cell sorting (FACS). The transfer rate of ABCB1 was measured by flow cytometry. The xenograft tumor models in mice were established to evaluate the transfer of ABCB1 in vivo. Gene expression was detected by real-time PCR and Western blotting.

Results

Herein, we show that a transient exposure to chemotherapeutic agents can strikingly increase Rab8B-mediated release of extracellular vesicles (EVs) containing ABCB1 from drug-resistant cells, and accelerate these EVs to circulate back onto plasma membrane of sensitive tumor cells via the down-regulation of Rab5. Therefore, intercellular ABCB1 transfer is significantly enhanced; sensitive recipient cells acquire a rapid but unsustainable resistance to evade the cytotoxicity of chemotherapeutic agents. More fascinatingly, in the xenograft tumor models, chemotherapeutical drugs also locally or distantly increase the transfer of ABCB1 molecules. Furthermore, some Non-small-cell lung carcinoma (NSCLC) patients who are undergoing primary chemotherapy have a rapid increase of ABCB1 protein in their monocytes, and this is obviously associated with poor chemotherapeutic efficacy.

Conclusions

Chemotherapeutic agents stimulate the secretion and recycling of ABCB1-enriched EVs through the dysregulation of Rab8B and Rab5, leading to a significant increase of ABCB1 intercellular transfer, thus assisting sensitive cancer cells to develop an urgent resistant phenotype. Our findings provide a new molecular mechanism of how chemotherapeutic drugs assist sensitive cancer cells in acquiring an urgent resistance.

Elevated Uric Acid Levels Promote Vascular Smooth Muscle Cells (VSMC) Proliferation via an Nod-Like Receptor Protein 3 (NLRP3)-Inflammasome-Dependent Mechanism

BACKGROUND Hyperuricemia has a pathogenic role in the development of hypertension and other cardiovascular diseases (CVD). Uric acid has been reported to activate Nod-like receptor protein 3 (NLRP3)-inflammasome and alter vascular smooth muscle cells (VSMC). However, the potential mechanisms underlying this association are still not understood. The aim of this study was to investigate the role and potential mechanisms of uric acid in proliferation of VSMC. MATERIAL AND METHODS Cell Counting Kit-8 (CCK-8) proliferation assay and colony formation assay were performed to determine the proliferative ability of VSMC under uric acid stimulation. Immunofluorescence microscopy was carried out to determine the expression of Alpha-smooth muscle actin (alpha-SMA). In addition, real-time PCR and Western blot were used to detect the expression of NLRP3-inflammasome, and ELISA was performed to measure the levels of IL-18 and IL-1ß. RESULTS The results showed that uric acid increases the proliferation of VSMC and induces alpha-SMA accumulation. We also found that uric acid increases the level of NLRP3 and induces NLRP3-inflammasome activation. The expressions of uric acid-induced inflammatory markers IL-1ß and IL-18 were decreased by the inhibitor MCC950. CONCLUSIONS Our findings revealed that uric acid induces inflammation through NLRP3-inflammasome-mediated VSMC proliferation. NLRP3 may be a new therapeutic target for hypertension.

Mesenchymal stem cell-derived extracellular vesicles for the treatment of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a serious and potentially fatal acute inflammatory lung condition which currently has no specific treatments targeting its pathophysiology. However, mesenchymal stem cells have been shown to have very promising therapeutic potential, and recently, it has been established that their effect is largely due to the transfer of extracellular vesicles (EVs). EVs have been shown to transfer a variety of substances such as mRNA, miRNA, and even organelles such as mitochondria in order to ameliorate ARDS in preclinical models. In addition, the fact that they have been proven to have the same effect as their parent cells combined with their numerous advantages over whole cell administration means that they are a promising candidate for clinical application that merits further research.

The role of microvesicles and its active molecules in regulating cellular biology

Cell‐derived microvesicles are membrane vesicles produced by the outward budding of the plasma membrane and released by almost all types of cells. These have been considered as another mechanism of intercellular communication, because they carry active molecules, such as proteins, lipids and nucleic acids. Furthermore, these are present in circulating fluids, such as blood and urine, and are closely correlated to the progression of pathophysiological conditions in many diseases. Recent studies have revealed that microvesicles have a dual effect of damage and protection of receptor cells. However, the nature of the active molecules involved in this effect remains unclear. The present study mainly emphasized the mechanism of microvesicles and the active molecules mediating the different biological effects of receptor cells by affecting autophagy, apoptosis and inflammation pathways. The effective ways of blocking microvesicles and its active molecules in mediating cell damage when microvesicles exert harmful effects were also discussed.