Extracellular vesicle-mediated transfer of genetic information between the hematopoietic system and the brain in response to inflammation

A longitudinal study of alterations of circulating DJ-1 and miR203a-3p in association to olanzapine medication in a sample of first episode patients with schizophrenia

Among different proposed pathophysiological mechanisms, redox imbalance has been suggested to be a potential contributor in the pathogenesis of schizophrenia. DJ-1 is a redox-sensitive protein that has been shown to have neuroprotective function in the brain in Parkinson's disease and other neurodegenerative diseases. However, a role for DJ-1 in schizophrenia is unknown. Bioinformatic analysis suggested that microRNA (miR)-203a-3p could target the 3' untranslated region (UTR) of DJ-1. In whole blood and blood-derived exosomes of 11 first episode antipsychotic naïve schizophrenia patients, DJ-1 protein and mRNA demonstrated decreased DJ-1 mRNA and protein and increased miR203a-3p levels compared to healthy controls. In whole blood, antipsychotic monotherapy with olanzapine for 6 weeks increased DJ-1 and attenuated miR203a-3p levels, whereas in blood derived exosomes, olanzapine returned DJ-1 and miR203a-3p to levels seen healthy controls. Consistent with this finding, we showed that human umbilical vein endothelial cells (HUVACs) transfected with a DJ-1-3' UTR luciferase reporter construct displayed reduced gene expression when subjected to the oxidative stressor H₂O_2. Transfection of a miR203a-3p mimic into HUVACs reduced DJ-1-3 'UTR reporter gene expression, while transfection of an anti miR-203a-3p prevented the H₂O₂-induced downregulation of the reporter gene. We conclude that miR-203a-3p is an essential mediator of oxidative stress in schizophrenia via its ability to target the 3' UTR of DJ-1 and antipsychotic monotherapy restores DJ-1 antioxidant levels by regulating miR203a-3p expression. miR-203a-3p and DJ-1 might represent attractive targets for the treatment of pathologies such as schizophrenia that has underlying oxidative stress.

Differential Expression of Serum Extracellular Vesicle miRNAs in Multiple Sclerosis: Disease-Stage Specificity and Relevance to Pathophysiology

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). Its first clinical presentation (clinically isolated syndrome, CIS) is often followed by the development of relapsing–remitting MS (RRMS). The periphery-to-CNS transmission of inflammatory molecules is a major pathophysiological pathway in MS. This could include signalling via extracellular vesicle (EV) microRNAs (miRNAs). In this study, we investigated the serum EV miRNome in CIS and RRMS patients and matched controls, with the aims to identify MS stage-specific differentially expressed miRNAs and investigate their biomarker potential and pathophysiological relevance. miRNA sequencing was conducted on serum EVs from CIS-remission, RRMS-relapse, and viral inflammatory CNS disorder patients, as well as from healthy and hospitalized controls. Differential expression analysis was conducted, followed by predictive power and target-pathway analysis. A moderate number of dysregulated serum EV miRNAs were identified in CIS-remission and RRMS-relapse patients, especially relative to healthy controls. Some of these miRNAs were also differentially expressed between the two MS stages and had biomarker potential for patient-control and CIS–RRMS separations. For the mRNA targets of the RRMS-relapse-specific EV miRNAs, biological processes inherent to MS pathophysiology were identified using in silico analysis. Study findings demonstrate that specific serum EV miRNAs have MS stage-specific biomarker potential and contribute to the identification of potential targets for novel, efficacious therapies.

Exosomes derived from platelet-rich plasma administration in site mediate cartilage protection in subtalar osteoarthritis

Subtalar osteoarthritis (STOA) is often secondary to chronic ankle sprains, which seriously affects the quality of life of patients. Due to its etiology and pathogenesis was not studied equivocally yet, there is currently a lack of effective conservative treatments. Although they have been used for tissue repair, platelet-rich plasma-derived exosomes (PRP-Exo) have the disadvantage of low retention and short-lived therapeutic effects. This study aimed to determine whether incorporation of PRP-Exo in thermosensitive hydrogel (Gel) increased their retention in the joint and thereby playing a therapeutic role on STOA due to chronic mechanical instability established by transecting lateral ligaments (anterior talofibular ligament (ATFL)/calcaneal fibular ligament (CFL)). PRP-Exo incorporated Gel (Exo-Gel) system, composed of Poloxamer-407 and 188 mixture-based thermoresponsive hydrogel matrix in an optimal ratio, was determined by its release ability of Exo and rheology of Gel response to different temperature. The biological activity of Exo-Gel was evaluated in vitro, and the therapeutic effect of Exo-Gel on STOA was evaluated in vivo. Exo released from Exo-Gel continuously for 28 days could promote the proliferation and migration of mouse bone mesenchymal stem cells (mBMSCs) and chondrocytes, at the same time enhance the chondrogenic differentiation of mBMSCs, and inhibit inflammation-induced chondrocyte degeneration. In vivo experiments confirmed that Exo-Gel increased the local retention of Exo, inhibited the apoptosis and hypertrophy of chondrocytes, enhanced their proliferation, and potentially played the role in stem cell recruitment to delay the development of STOA. Thus, Delivery of PRP-Exo incorporated in thermosensitive Gel provides a novel approach of cell-free therapy and has therapeutic effect on STOA.

Graphical Abstract

Surgical Trauma in Mice Modifies the Content of Circulating Extracellular Vesicles

Surgical interventions rapidly trigger a cascade of molecular, cellular, and neural signaling responses that ultimately reach remote organs, including the brain. Using a mouse model of orthopedic surgery, we have previously demonstrated hippocampal metabolic, structural, and functional changes associated with cognitive impairment. However, the nature of the underlying signals responsible for such periphery-to-brain communication remains hitherto elusive. Here we present the first exploratory study that tests the hypothesis of extracellular vesicles (EVs) as potential mediators carrying information from the injured tissue to the distal organs including the brain. The primary goal was to investigate whether the cargo of circulating EVs after surgery can undergo quantitative changes that could potentially trigger phenotypic modifications in the target tissues. EVs were isolated from the serum of the mice subjected to a tibia surgery after 6, 24, and 72 h, and the proteome and miRNAome were investigated using mass spectrometry and RNA-seq approaches. We found substantial differential expression of proteins and miRNAs starting at 6 h post-surgery and peaking at 24 h. Interestingly, one of the up-regulated proteins at 24 h was α-synuclein, a pathogenic hallmark of certain neurodegenerative syndromes. Analysis of miRNA target mRNA and corresponding biological pathways indicate the potential of post-surgery EVs to modify the extracellular matrix of the recipient cells and regulate metabolic processes including fatty acid metabolism. We conclude that surgery alters the cargo of circulating EVs in the blood, and our results suggest EVs as potential systemic signal carriers mediating remote effects of surgery on the brain.

Evidence for Effects of Extracellular Vesicles on Physical, Inflammatory, Transcriptome and Reward Behaviour Status in Mice

Immune-inflammatory activation impacts extracellular vesicles (EVs), including their miRNA cargo. There is evidence for changes in the EV miRNome in inflammation-associated neuropsychiatric disorders. This mouse study investigated: (1) effects of systemic lipopolysaccharide (LPS) and chronic social stress (CSS) on plasma EV miRNome; and (2) physiological, transcriptional, and behavioural effects of peripheral or central delivered LPS-activated EVs in recipient mice. LPS or CSS effects on the plasma EV miRNome were assessed by using microRNA sequencing. Recipient mice received plasma EVs isolated from LPS-treated or SAL-treated donor mice or vehicle only, either intravenously or into the nucleus accumbens (NAc), on three consecutive days. Bodyweight, spleen or NAc transcriptome and reward (sucrose) motivation were assessed. LPS and CSS increased the expression of 122 and decreased expression of 20 plasma EV miRNAs, respectively. Peripheral LPS-EVs reduced bodyweight, and both LPS-EVs and SAL-EVs increased spleen expression of immune-relevant genes. NAc-infused LPS-EVs increased the expression of 10 immune-inflammatory genes. Whereas motivation increased similarly across test days in all groups, the effect of test days was more pronounced in mice that received peripheral or central LPS-EVs compared with other groups. This study provides causal evidence that increased EV levels impact physiological and behavioural processes and are of potential relevance to neuropsychiatric disorders.

Cerebral derailment after myocardial infarct: mechanisms and effects of the signaling from the ischemic heart to brain

Myocardial infarction (MI) is the leading cause of death among ischemic heart diseases and is associated with several long-term cardiovascular complications, such as angina, re-infarction, arrhythmias, and heart failure. However, MI is frequently accompanied by non-cardiovascular multiple comorbidities, including brain disorders such as stroke, anxiety, depression, and cognitive impairment. Accumulating experimental and clinical evidence suggests a causal relationship between MI and stroke, but the precise underlying mechanisms have not yet been elucidated. Indeed, the risk of stroke remains a current challenge in patients with MI, in spite of the improvement of medical treatment among this patient population has reduced the risk of stroke. In this review, the effects of the signaling from the ischemic heart to the brain, such as neuroinflammation, neuronal apoptosis, and neurogenesis, and the possible actors mediating these effects, such as systemic inflammation, immunoresponse, extracellular vesicles, and microRNAs, are discussed.

In sickness and in health: The functional role of extracellular vesicles in physiology and pathology in vivo: Part I: Health and Normal Physiology: Part I: Health and Normal Physiology

Previously thought to be nothing more than cellular debris, extracellular vesicles (EVs) are now known to mediate physiological and pathological functions throughout the body. We now understand more about their capacity to transfer nucleic acids and proteins between distant organs, the interaction of their surface proteins with target cells, and the role of vesicle-bound lipids in health and disease. To date, most observations have been made in reductionist cell culture systems, or as snapshots from patient cohorts. The heterogenous population of vesicles produced in vivo likely act in concert to mediate both beneficial and detrimental effects. EVs play crucial roles in both the pathogenesis of diseases, from cancer to neurodegenerative disease, as well as in the maintenance of system and organ homeostasis. This two-part review draws on the expertise of researchers working in the field of EV biology and aims to cover the functional role of EVs in physiology and pathology. Part I will outline the role of EVs in normal physiology.

Extracellular vesicles in obesity and its associated inflammation

Obesity is characterized by low-grade, chronic inflammation, which promotes insulin resistance and diabetes. Obesity can lead to the development and progression of many autoimmune diseases, including inflammatory bowel disease, psoriasis, psoriatic arthritis, rheumatoid arthritis, thyroid autoimmunity, and type 1 diabetes mellitus (T1DM). These diseases result from an alteration of self-tolerance by promoting pro-inflammatory immune response by lowering numbers of regulatory T cells (T_regs), increasing Th1 and Th17 immune responses, and inflammatory cytokine production. Therefore, understanding the immunological changes that lead to this low-grade inflammatory milieu becomes crucial for the development of therapies that suppress the risk of autoimmune diseases and other immunological conditions. Cells generate extracellular vesicles (EVs) to eliminate cellular waste as well as communicating the adjacent and distant cells through exchanging the components (genetic material [DNA or RNA], lipids, and proteins) between them. Immune cells and adipocytes from individuals with obesity and a high basal metabolic index (BMI) produce also release exosomes (EXOs) and microvesicles (MVs), which are collectively called EVs. These EVs play a crucial role in the development of autoimmune diseases. The current review discusses the immunological dysregulation that leads to inflammation, inflammatory diseases associated with obesity, and the role played by EXOs and MVs in the induction and progression of this devastating conditi8on.

Effects of an acute exercise bout in hypoxia on extracellular vesicle release in healthy and prediabetic subjects

PURPOSE

To investigate exosome-like vesicle (ELV) plasma concentrations and markers of multivesicular body (MVB) biogenesis in skeletal muscle in response to acute exercise.

METHODS

Seventeen healthy (BMI: 23.5±0.5kg·m^-2) and fifteen prediabetic (BMI: 27.3±1.2kg·m^-2) men were randomly assigned to two groups performing an acute cycling bout in normoxia or hypoxia (FiO₂ 14.0%). Venous blood samples were taken before (T0), during (T30) and after (T60) exercise and biopsies from m. vastus lateralis were collected before and after exercise. Plasma ELVs were isolated by size exclusion chromatography, counted by nanoparticle tracking analysis (NTA), and characterized according to international standards, followed by expression analyses of canonical ELV markers in skeletal muscle.

RESULTS

In the healthy normoxic group, the total number of particles in the plasma increased during exercise from T0 to T30 (+313%) followed by a decrease from T30 to T60 (-53%). In the same group, an increase in TSG101, CD81 and HSP60 protein expression was measured after exercise in plasma ELVs; however, in the prediabetic group, the total number of particles in the plasma was not affected by exercise. The mRNA content of TSG101, ALIX and CD9 were upregulated in skeletal muscle after exercise in normoxia; whereas, CD9 and CD81 were downregulated in hypoxia.

CONCLUSIONS

ELV plasma abundance increased in response to acute aerobic exercise in healthy subjects in normoxia, but not in prediabetic subjects, nor in hypoxia. Skeletal muscle analyses suggested that this tissue did not likely play a major role of the exercise-induced increase in circulating ELVs.

MicroRNAs are minor constituents of extracellular vesicles that are rarely delivered to target cells

Mammalian cells release different types of vesicles, collectively termed extracellular vesicles (EVs). EVs contain cellular microRNAs (miRNAs) with an apparent potential to deliver their miRNA cargo to recipient cells to affect the stability of individual mRNAs and the cells’ transcriptome. The extent to which miRNAs are exported via the EV route and whether they contribute to cell-cell communication are controversial. To address these issues, we defined multiple properties of EVs and analyzed their capacity to deliver packaged miRNAs into target cells to exert biological functions. We applied well-defined approaches to produce and characterize purified EVs with or without specific viral miRNAs. We found that only a small fraction of EVs carried miRNAs. EVs readily bound to different target cell types, but EVs did not fuse detectably with cellular membranes to deliver their cargo. We engineered EVs to be fusogenic and document their capacity to deliver functional messenger RNAs. Engineered fusogenic EVs, however, did not detectably alter the functionality of cells exposed to miRNA-carrying EVs. These results suggest that EV-borne miRNAs do not act as effectors of cell-to-cell communication.

The majority of metazoan cells release vesicles of different types and origins, such as exosomes and microvesicles, now collectively termed extracellular vesicles (EVs). EVs have gained much attention because they contain microRNAs (miRNAs) and thus could regulate their specific mRNA targets in recipient or acceptor cells that take up EVs. Using a novel fusion assay with superior sensitivity and specificity, we revisited this claim but found no convincing evidence for an efficient functional uptake of EVs in many different cell lines and primary human blood cells. Even EVs engineered to fuse and deliver their miRNA cargo to recipient cells had no measurable effect on target mRNAs in very carefully controlled, quantitative experiments. Our negative results clearly indicate that EVs do not act as vehicles for miRNA-based cell-to-cell communication.

Small Extracellular Vesicles Propagate the Inflammatory Response After Trauma

Trauma is the leading cause of death in individuals under 44 years of age. Thorax trauma (TxT) is strongly associated with trauma-related death, an unbalanced innate immune response, sepsis, acute respiratory distress syndrome, and multiple organ dysfunction. It is shown that different in vivo traumata, such as TxT or an in vitro polytrauma cytokine cocktail trigger secretion of small extracellular nanovesicles (sEVs) from endothelial cells with pro-inflammatory cargo. These sEVs transfer transcripts for ICAM-1, VCAM-1, E-selectin, and cytokines to systemically activate the endothelium, facilitate neutrophil-endothelium interactions, and destabilize barrier integrity. Inhibition of sEV-release after TxT in mice ameliorates local as well as systemic inflammation, neutrophil infiltration, and distant organ damage in kidneys (acute kidney injury, AKI). Vice versa, injection of TxT-plasma-sEVs into healthy animals is sufficient to trigger pulmonary and systemic inflammation as well as AKI. Accordingly, increased sEV concentrations and transfer of similar cargos are observed in polytrauma patients, suggesting a fundamental pathophysiological mechanism.

Thinking Quantitatively of RNA-Based Information Transfer via Extracellular Vesicles: Lessons to Learn for the Design of RNA-Loaded EVs

Extracellular vesicles (EVs) are 50–1000 nm vesicles secreted by virtually any cell type in the body. They are expected to transfer information from one cell or tissue to another in a short- or long-distance way. RNA-based transfer of information via EVs at long distances is an interesting well-worn hypothesis which is ~15 years old. We review from a quantitative point of view the different facets of this hypothesis, ranging from natural RNA loading in EVs, EV pharmacokinetic modeling, EV targeting, endosomal escape and RNA delivery efficiency. Despite the unique intracellular delivery properties endowed by EVs, we show that the transfer of RNA naturally present in EVs might be limited in a physiological context and discuss the lessons we can learn from this example to design efficient RNA-loaded engineered EVs for biotherapies. We also discuss other potential EV mediated information transfer mechanisms, among which are ligand–receptor mechanisms.

Formation, contents, functions of exosomes and their potential in lung cancer diagnostics and therapeutics

Lung cancer is the leading cause of cancer-related death worldwide due to diagnosis in the advanced stage and drug resistance in the subsequent treatments. Development of novel diagnostic and therapeutic methods is urged to improve the disease outcome. Exosomes are nano-sized vehicles which transport different types of biomolecules intercellularly, including DNA, RNA and proteins, and are implicated in cross-talk between cells and their surrounding microenvironment. Tumor-derived exosomes (TEXs) have been revealed to strongly influence the tumor microenvironment, antitumor immunoregulatory activities, tumor progression and metastasis. Potential of TEXs as biomarkers for lung cancer diagnosis, prognosis and treatment prediction is supported by numerous studies. Moreover, exosomes have been proposed to be promising drug carriers. Here, we review the mechanisms of exosomal formation and uptake, the functions of exosomes in carcinogenesis, and potential clinical utility of exosomes as biomarkers, tumor vaccine and drug delivery vehicles in the diagnosis and therapeutics of lung cancer.

Role of Extracellular Vesicle-Derived Biomarkers in Drug Metabolism and Disposition

Extracellular vesicles (EVs) are small, nonreplicating, lipid-encapsulated particles that contain a myriad of protein and nucleic acid cargo derived from their tissue of origin. The potential role of EV-derived biomarkers to the study of drug metabolism and disposition (DMD) has gained attention in recent years. The key trait that makes EVs an attractive biomarker source is their capacity to provide comparable insights to solid organ biopsy through an appreciably less invasive collection procedure. Blood-derived EVs exist as a heterogenous milieu of biologically distinct particles originating from different sources through different biogenesis pathways. Furthermore, blood (plasma and serum) contains an array of vesicular and nonvesicular contaminants, such as apoptotic bodies, plasma proteins, and lipoproteins that are routinely coisolated with EVs, albeit to a different extent depending on the isolation technique. The following minireview summarizes current studies reporting DMD biomarkers and addresses elements of EV isolation and quantification relevant to the application of EV-derived DMD biomarkers. Evidence based-best practice guidance aligned to Minimum Information for the Study of Extracellular Vesicles and EV-TRACK reporting standards are summarized in the context of DMD studies. SIGNIFICANCE STATEMENT: Extracellular vesicle (EV)-derived protein and nucleic acid cargo represent a potentially game-changing source of novel DMD biomarkers with the capacity to define within- and between-individual variability in drug exposure irrespective of etiology. However, robust translation of EV-derived biomarkers requires the generation of transparent reproducible evidence. This review outlines the critical elements of data generation and reporting relevant to achieving this evidence in a drug metabolism and disposition context.

Extracellular Vesicles: A New Paradigm for Cellular Communication in Perioperative Medicine, Critical Care, and Pain Management

Extracellular vesicles (EVs) play critical roles in many health and disease states, including ischemia, inflammation, and pain, which are major concerns in the perioperative period and in critically ill patients. EVs are functionally active, nanometer-sized, membrane-bound vesicles actively secreted by all cells. Cell signaling is essential to physiological and pathological processes, and EVs have recently emerged as key players in intercellular communication. Recent studies in EV biology have improved our mechanistic knowledge of the pathophysiological processes in perioperative and critical care patients. Studies also show promise in using EVs in novel diagnostic and therapeutic clinical applications. This review considers the current advances and gaps in knowledge of EVs in the areas of ischemia, inflammation, pain, and in organ systems that are most relevant to anesthesiology, perioperative medicine, critical care, and pain management. We expect the reader will better understand the relationship between EVs and perioperative and critical care pathophysiological states and their potential use as novel diagnostic and therapeutic modalities.

In vivo imaging of EVs in zebrafish: New perspectives from "the waterside"

To harmoniously coordinate the activities of all its different cell types, a multicellular organism critically depends on intercellular communication. One recently discovered mode of intercellular cross-talk is based on the exchange of "extracellular vesicles" (EVs). EVs are nano-sized heterogeneous lipid bilayer vesicles enriched in a variety of biomolecules that mediate short- and long-distance communication between different cells, and between cells and their environment. Numerous studies have demonstrated important aspects pertaining to the dynamics of their release, their uptake, and sub-cellular fate and roles in vitro. However, to demonstrate these and other aspects of EV biology in a relevant, fully physiological context in vivo remains challenging. In this review we analyze the state of the art of EV imaging in vivo, focusing in particular on zebrafish as a promising model to visualize, study, and characterize endogenous EVs in real-time and expand our understanding of EV biology at cellular and systems level.

SnRNA sequencing defines signaling by RBC-derived extracellular vesicles in the murine heart

In a unique model of fluorescent based mapping of EV recipient cells, RBC-EVs were found to signal to cardiac cells and regulate gene expression in a model of ischemic heart failure.

Extracellular vesicles (EVs) mediate intercellular signaling by transferring their cargo to recipient cells, but the functional consequences of signaling are not fully appreciated. RBC-derived EVs are abundant in circulation and have been implicated in regulating immune responses. Here, we use a transgenic mouse model for fluorescence-based mapping of RBC-EV recipient cells to assess the role of this intercellular signaling mechanism in heart disease. Using fluorescent-based mapping, we detected an increase in RBC-EV–targeted cardiomyocytes in a murine model of ischemic heart failure. Single cell nuclear RNA sequencing of the heart revealed a complex landscape of cardiac cells targeted by RBC-EVs, with enrichment of genes implicated in cell proliferation and stress signaling pathways compared with non-targeted cells. Correspondingly, cardiomyocytes targeted by RBC-EVs more frequently express cellular markers of DNA synthesis, suggesting the functional significance of EV-mediated signaling. In conclusion, our mouse model for mapping of EV-recipient cells reveals a complex cellular network of RBC-EV–mediated intercellular communication in ischemic heart failure and suggests a functional role for this mode of intercellular signaling.

Mesenchymal Stem Cell-Derived Extracellular Vesicle-Based Therapy for Alzheimer's Disease: Progress and Opportunity

Alzheimer's disease (AD), as a neurodegenerative disorder, is characterized by mass neuronal and synaptic loss and, currently, there are no successful curative therapies. Extracellular vesicles (EVs) are an emerging approach to intercellular communication via transferring cellular materials such as proteins, lipids, mRNAs, and miRNAs from parental cells to recipient cells, leading to the reprogramming of the molecular machinery. Numerous studies have suggested the therapeutic potential of EVs derived from mesenchymal stem cells (MSCs) in the treatment of AD, based on the neuroprotective, regenerative and immunomodulatory effects as effective as MSCs. In this review, we focus on the biology and function of EVs, the potential of MSC-derived EVs for AD therapy in preclinical and clinical studies, as well as the potent mechanisms of MSC-derived EVs actions. Finally, we highlight the modification strategies and diagnosis utilities in order to make advance in this field.

Engineered extracellular vesicles as brain therapeutics

Extracellular vesicles (EVs) are communication channels between different cell types in the brain, between the brain and the periphery and vice-versa, playing a fundamental role in physiology and pathology. The evidence that EVs might be able to cross the blood-brain barrier (BBB) make them very promising candidates as nanocarriers to treat brain pathologies. EVs contain a cocktail of bioactive factors, yet their content and surface can be further engineered to enhance their biological activity, stability and targeting ability. Native and engineered EVs have been reported for the treatment of different brain pathologies, although issues related to their modest accumulation and limited local therapeutic effect in the brain still need to be addressed. In this review, we cover the therapeutic applications of native and bioengineered EVs for brain diseases. We also review recent data about the interaction between EVs and the BBB and discuss the challenges and opportunities in clinical translation of EVs as brain therapeutics.

Visualizing transfer of microbial biomolecules by outer membrane vesicles in microbe-host-communication in vivo

The intestinal microbiota influences mammalian host physiology in health and disease locally in the gut but also in organs devoid of direct contact with bacteria such as the liver and brain. Extracellular vesicles (EVs) or outer membrane vesicles (OMVs) released by microbes are increasingly recognized for their potential role as biological shuttle systems for inter-kingdom communication. However, physiologically relevant evidence for the transfer of functional biomolecules from the intestinal microbiota to individual host cells by OMVs in vivo is scarce. By introducing Escherichia coli engineered to express Cre-recombinase (E. coliCre ) into mice with a Rosa26.tdTomato-reporter background, we leveraged the Cre-LoxP system to report the transfer of bacterial OMVs to recipient cells in vivo. Colonizing the intestine of these mice with E. coliCre , resulted in Cre-recombinase induced fluorescent reporter gene-expression in cells along the intestinal epithelium, including intestinal stem cells as well as mucosal immune cells such as macrophages. Furthermore, even far beyond the gut, bacterial-derived Cre induced extended marker gene expression in a wide range of host tissues, including the heart, liver, kidney, spleen, and brain. Together, our findings provide a method and proof of principle that OMVs can serve as a biological shuttle system for the horizontal transfer of functional biomolecules between bacteria and mammalian host cells.

Secret messengers: Extracellular RNA communication in the immune system

One of the hallmarks of the immune system is a dynamic landscape of cellular communication through the secretion of soluble factors, production of cell-bound ligands, and expression of surface receptors. This communication affects all aspects of immune cell behavior, integrates the responses of immune cells in tissues, and is fundamental to orchestrating effective immunity. Recent pioneering work has shown that the transfer of ribonucleic acids (RNAs) constitutes a novel mode of cellular communication. This communication involves diverse RNA species, with short noncoding RNAs especially enriched in the extracellular space. These RNAs are highly stable and selectively packaged for secretion. Transferred RNAs have functions in target cells that both mirror their cell-intrinsic roles and adopt novel mechanisms of action. These extracellular RNAs both impact the behavior of individual immune cells and participate in local and systemic immune responses. The impacts of RNA communication on immune cells and disease states have important implications for the development of novel clinical biomarkers and innovative therapeutic designs in immune-related disease. In this review, we will discuss the foundation of knowledge that is establishing RNA communication as an active and functional process in the immune system.

A Comprehensive Insight into the Role of Exosomes in Viral Infection: Dual Faces Bearing Different Functions

Extracellular vesicles (EVs) subtype, exosome is an extracellular nano-vesicle that sheds from cells' surface and originates as intraluminal vesicles during endocytosis. Firstly, it was thought to be a way for the cell to get rid of unwanted materials as it loaded selectively with a variety of cellular molecules, including RNAs, proteins, and lipids. However, it has been found to play a crucial role in several biological processes such as immune modulation, cellular communication, and their role as vehicles to transport biologically active molecules. The latest discoveries have revealed that many viruses export their viral elements within cellular factors using exosomes. Hijacking the exosomal pathway by viruses influences downstream processes such as viral propagation and cellular immunity and modulates the cellular microenvironment. In this manuscript, we reviewed exosomes biogenesis and their role in the immune response to viral infection. In addition, we provided a summary of how some pathogenic viruses hijacked this normal physiological process. Viral components are harbored in exosomes and the role of these exosomes in viral infection is discussed. Understanding the nature of exosomes and their role in viral infections is fundamental for future development for them to be used as a vaccine or as a non-classical therapeutic strategy to control several viral infections.

The power of imaging to understand extracellular vesicle biology in vivo

Extracellular vesicles (EVs) are nano-sized lipid bilayer vesicles released by virtually every cell type. EVs have diverse biological activities, ranging from roles in development and homeostasis to cancer progression, which has spurred the development of EVs as disease biomarkers and drug nanovehicles. Owing to the small size of EVs, however, most studies have relied on isolation and biochemical analysis of bulk EVs separated from biofluids. Although informative, these approaches do not capture the dynamics of EV release, biodistribution, and other contributions to pathophysiology. Recent advances in live and high-resolution microscopy techniques, combined with innovative EV labeling strategies and reporter systems, provide new tools to study EVs in vivo in their physiological environment and at the single-vesicle level. Here we critically review the latest advances and challenges in EV imaging, and identify urgent, outstanding questions in our quest to unravel EV biology and therapeutic applications.

Biological Functions Driven by mRNAs Carried by Extracellular Vesicles in Cancer

Extracellular vesicles (EVs), including exosomes and microvesicles, are extracellular nanovesicles released by most cells. EVs play essential roles in intercellular communication via the transport of a large variety of lipids, proteins, and nucleic acids to recipient cells. Nucleic acids are the most commonly found molecules inside EVs, and due to their small size, microRNAs and other small RNAs are the most abundant nucleic acids. However, longer molecules, such as messenger RNAs (mRNAs), have also been found. mRNAs encapsulated within EVs have been shown to be transferred to recipient cells and translated into proteins, altering the behavior of the cells. Secretion of EVs is maintained not only through multiple normal physiological conditions but also during aberrant pathological conditions, including cancer. Recently, the mRNAs carried by EVs in cancer have attracted great interest due to their broad roles in tumor progression and microenvironmental remodeling. This review focuses on the biological functions driven by mRNAs carried in EVs in cancer, which include supporting tumor progression by activating cancer cell growth, migration, and invasion; inducing microenvironmental remodeling via hypoxia, angiogenesis, and immunosuppression; and promoting modulation of the microenvironment at distant sites for the generation of a premetastatic niche, collectively inducing metastasis. Furthermore, we describe the potential use of mRNAs carried by EVs as a noninvasive diagnostic tool and novel therapeutic approach.

Extracellular Vesicles in neural cell interaction and CNS homeostasis

Central nervous system (CNS) homeostasis critically depends on the interaction between neurons and glia cells. Extracellular vesicles (EVs) recently emerged as versatile messengers in CNS cell communication. EVs are released by neurons and glia in activity-dependent manner and address multiple target cells within and outside the nervous system. Here, we summarize the recent advances in understanding the physiological roles of EVs in the nervous system and their ability to deliver signals across the CNS barriers. In addition to the disposal of cellular components via EVs and clearance by phagocytic cells, EVs are involved in plasticity-associated processes, mediate trophic support and neuroprotection, promote axonal maintenance, and modulate neuroinflammation. While individual functional components of the EV cargo are becoming progressively identified, the role of neural EVs as compound multimodal signaling entities remains to be elucidated. Novel transgenic models and imaging technologies allow EV tracking in vivo and provide further insight into EV targeting and their mode of action. Overall, EVs represent key players in the maintenance of CNS homeostasis essential for the lifelong performance of neural networks and thus provide a wide spectrum of biomedical applications.

Extracellular Vesicles in Multiple Sclerosis: Role in the Pathogenesis and Potential Usefulness as Biomarkers and Therapeutic Tools

Although extracellular vesicles (EVs) were initially relegated to a waste disposal role, nowadays, they have gained multiple fundamental functions working as messengers in intercellular communication as well as exerting active roles in physiological and pathological processes. Accumulating evidence proves the involvement of EVs in many diseases, including those of the central nervous system (CNS), such as multiple sclerosis (MS). Indeed, these membrane-bound particles, produced in any type of cell, carry and release a vast range of bioactive molecules (nucleic acids, proteins, and lipids), conferring genotypic and phenotypic changes to the recipient cell. This means that not only EVs per se but their content, especially, could reveal new candidate disease biomarkers and/or therapeutic agents. This review is intended to provide an overview regarding current knowledge about EVs’ involvement in MS, analyzing the potential versatility of EVs as a new therapeutic tool and source of biomarkers.

Illuminating RNA trafficking and functional delivery by extracellular vesicles

RNA-based therapeutics are highly promising for the treatment of numerous diseases, by their ability to tackle the genetic origin in multiple possible ways. RNA molecules are, however, incapable of crossing cell membranes, hence a safe and efficient delivery vehicle is pivotal. Extracellular vesicles (EVs) are endogenously derived nano-sized particles and possess several characteristics which make them excellent candidates as therapeutic RNA delivery agent. This includes the inherent capability to functionally transfer RNAs in a selective manner and an enhanced safety profile compared to synthetic particles. Nonetheless, the fundamental mechanisms underlying this selective inter- and intracellular trafficking and functional transfer of RNAs by EVs are poorly understood. Improving our understanding of these systems is a key element of working towards an EV-based or EV-mimicking system for the functional delivery of therapeutic RNA. In this review, state-of-the-art approaches to detect and visualize RNA in situ and in live cells are discussed, as well as strategies to assess functional RNA transfer, highlighting their potential in studying EV-RNA trafficking mechanisms.

Understanding extracellular vesicle and nanoparticle heterogeneity: Novel methods and considerations

Extracellular vesicles (EVs) are a heterogeneous population of membrane-enclosed nanoparticles released by cells. They play a role in intercellular communication and are involved in numerous physiological and pathological processes. Cells release subpopulations of EVs with distinct composition and inherent biological function which overlap in size. Current size-based isolation methods are, therefore, not optimal to discriminate between functional EV subpopulations. In addition, EVs overlap in size with several other biological nanoparticles, such as lipoproteins and viruses. Proteomic analysis has allowed for more detailed study of EV composition, and EV isolation approaches based on this could provide a promising alternative for purification based on size. Elucidating EV heterogeneity and the characteristics and role of EV subpopulations will advance our understanding of EV biology and the role of EVs in health and disease. Here, we discuss current knowledge of EV composition, EV heterogeneity and advances in affinity based EV isolation tools.

Separation, characterization, and standardization of extracellular vesicles for drug delivery applications

Extracellular vesicles (EVs) are membranous nanovesicles secreted from living cells, shuttling macromolecules in intercellular communication and potentially possessing intrinsic therapeutic activity. Due to their stability, low immunogenicity, and inherent interaction with recipient cells, EVs also hold great promise as drug delivery vehicles. Indeed, they have been used to deliver nucleic acids, proteins, and small molecules in preclinical investigations. Furthermore, EV-based drugs have entered early clinical trials for cancer or neurodegenerative diseases. Despite their appeal as delivery vectors, however, EV-based drug delivery progress has been hampered by heterogeneity of sample types and methods as well as a persistent lack of standardization, validation, and comprehensive reporting. This review highlights specific requirements for EVs in drug delivery and describes the most pertinent approaches for separation and characterization. Despite residual uncertainties related to pharmacodynamics, pharmacokinetics, and potential off-target effects, clinical-grade, high-potency EV drugs might be achievable through GMP-compliant workflows in a highly standardized environment.

Extracellular vesicles for remote brain repair

Recovery of brain function lost to disease or in old age is a challenging task in regenerative medicine. In the last two decades, therapeutic strategies have undergone significant shifts by a succession of major discoveries from adult neural stem cells and neurogenesis to the development of induced pluripotent stem cells to technologies for reprogramming cells in vitro and in vivo. Now, extracellular vesicles, small membrane-bound vesicles released by all cells and containing lipids, proteins, and nucleic acids, emerge as the next major technological opportunity. While substantial progress has been made on their potential use in therapy and EVs have entered many clinical trials, major aspects of their physiological role, in particular regarding their influence on brain function, remain unknown. However, a better understanding of their actual in vivo function, scope of communication, and possibilities to alter cellular processes in target cells will be needed. This review places EVs in the developing landscape of strategies for cellular repair of the brain and highlights their potential by looking at some recent progress in our understanding of their function in vivo.

Genetic and epigenetic regulation of cancer coagulome - lessons from heterogeneity of cancer cell populations

Cancer-associated thrombosis (CAT) is a morbid, potentially life threatening and biologically impactful paraneoplastic state. At least in part, CAT is likely driven by cancer-specific mechanisms the nature of which is still poorly understood, hampering diagnostic, prophylactic and therapeutic efforts. It is increasingly appreciated that cancer-specific drivers of CAT include a constellation of oncogenic mutations and their superimposed epigenetic states that shape the transcriptome, phenotype and secretome of cancer cell populations, including the repertoire of genes impacting the vascular and coagulation systems. High-grade brain tumours, such as glioblastoma multiforme (GBM) represent a paradigm of locally initiated haemostatic abnormalities that propagate systemically, likely through circulating mediators, such as extracellular vesicles and soluble factors. Reciprocally, CAT impacts the biology of cancer cells and may drive tumour evolution. The constituent, oncogene-transformed cancer cell populations form complex ecosystems, the intricate architecture of which has been recently revealed by single cell sequencing technologies. Amidst this phenotypic heterogeneity, several alternative pathways of CAT may exist both between and within individual tumours and their subtypes, including GBM. Indeed, different contributions of cells expressing key coagulant mediators, such as tissue factor, or podoplanin, have been identified in GBM subtypes driven by oncogenic mutations in EGFR, IDH1 and other transforming genes. Thus, a better understanding of cellular sources of CAT, including dominant cancer cell phenotypes and their dynamic shifts, may help design more personalised approaches to thrombosis in cancer patients to improve outcomes.

Extracellular Vesicles as an Emerging Frontier in Spinal Cord Injury Pathobiology and Therapy

Extracellular vesicles (EVs) are membrane-delimited particles that are secreted by nearly all cell types. EVs mediate crucial physiological functions and pathophysiological processes in the CNS. As carriers of diverse bioactive cargoes (e.g., proteins, lipids, and nucleic acids) that can be modified in response to external stimuli, EVs have emerged as pathological mediators following neurotrauma such as spinal cord injury (SCI). We discuss the roles of endogenous EVs in the CNS as well as crosstalk with peripheral EVs in relation to neurotrauma, with a particular focus on SCI. We then summarize the status of EV-based therapeutic advances in preclinical animal models for these conditions. Finally, we discuss new bioengineering strategies that are poised to enhance CNS-specific therapeutic capabilities of EVs.

Nucleic acid delivery with extracellular vesicles

Extracellular vesicles (EVs) are membrane-enclosed particles, heterogeneous in size, shape, contents, biogenesis and structure. They are released by eukaryotic and prokaryotic cells and exert (patho-)physiological roles as mediators for transmitting molecular information from the producer (donor) to a recipient cell. This review focuses on the potential of EVs for delivering nucleic acids, as particularly problematic cargoes with regard to stability/protection and uptake efficacy. It highlights important properties of EVs for nucleic acid delivery and discusses their physiological and pathophysiological roles with regard to various cellular RNA species. It then describes the application of EVs for delivering a broad selection of nucleic acids/oligonucleotides, in particular giving a comprehensive overview of preclinical in vivo studies and the various strategies explored. In this context, different techniques for EV loading are discussed, as well as other important technical aspects related to EV preparation, characterization and in particular, the various approaches of artificial EV modification.

Alterations in circulating extracellular vesicles underlie social stress-induced behaviors in mice

Chronic stress induces peripheral and intracerebral immune changes and inflammation, contributing to neuropathology and behavioral abnormalities relevant to psychiatric disorders such as depression. Although the pathological implication of many peripheral factors such as pro‐inflammatory cytokines, hormones, and macrophages has been demonstrated, the roles of circulating extracellular vesicles (EVs) for chronic stress mechanisms remain poorly investigated. Here, we report that chronic social defeat stress (CSDS)‐induced social avoidance phenotype, assessed by a previously untested three‐chamber social approach test, can be distinguished by multiple pro‐inflammatory cytokines and EV‐associated molecular signatures in the blood. We found that the expression patterns of miRNAs distinguished the CSDS‐susceptible mice from the CSDS‐resilient mice. Social avoidance behavior scores were also estimated with good accuracy by the expression patterns of multiple EV‐associated miRNAs. We also demonstrated that EVs enriched from the CSDS‐susceptible mouse sera upregulated the production of pro‐inflammatory cytokines in the LPS‐stimulated microglia‐like cell lines. Our results indicate the role of circulating EVs and associated miRNAs in CSDS susceptibility, which may be related to pro‐inflammatory mechanisms underlying stress‐induced neurobehavioral outcomes.

Sphingomyelinases in a journey to combat arthropod-borne pathogen transmission

Ixodes scapularis ticks feed on humans and other vertebrate hosts and transmit several pathogens of public health concern. Tick saliva is a complex mixture of bioactive proteins, lipids and immunomodulators, such as I. scapularis sphingomyelinase (IsSMase)-like protein, an ortholog of dermonecrotoxin SMase D found in the venom of Loxosceles spp. of spiders. IsSMase modulates the host immune response towards Th2, which suppresses Th1-mediated cytokines to facilitate pathogen transmission. Arboviruses utilize exosomes for their transmission from tick to the vertebrate host, and exosomes derived from tick saliva/salivary glands suppress C-X-C motif chemokine ligand 12 and interleukin-8 immune response(s) in human skin to delay wound healing and repair processes. IsSMase affects also viral replication and exosome biogenesis, thereby inhibiting tick-to-vertebrate host transmission of pathogenic exosomes. In this review, we elaborate on exosomes and their biogenesis as potential candidates for developing novel control measure(s) to combat tick-borne diseases. Such targets could help with the development of an efficient anti-tick vaccine for preventing the transmission of tick-borne pathogens.

Exosomes: Innocent Bystanders or Critical Culprits in Neurodegenerative Diseases

Extracellular vesicles (EVs) are nano-sized membrane-enclosed particles released by cells that participate in intercellular communication through the transfer of biologic material. EVs include exosomes that are small vesicles that were initially associated with the disposal of cellular garbage; however, recent findings point toward a function as natural carriers of a wide variety of genetic material and proteins. Indeed, exosomes are vesicle mediators of intercellular communication and maintenance of cellular homeostasis. The role of exosomes in health and age-associated diseases is far from being understood, but recent evidence implicates exosomes as causative players in the spread of neurodegenerative diseases. Cells from the central nervous system (CNS) use exosomes as a strategy not only to eliminate membranes, toxic proteins, and RNA species but also to mediate short and long cell-to-cell communication as carriers of important messengers and signals. The accumulation of protein aggregates is a common pathological hallmark in many neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and prion diseases. Protein aggregates can be removed and delivered to degradation by the endo-lysosomal pathway or can be incorporated in multivesicular bodies (MVBs) that are further released to the extracellular space as exosomes. Because exosome transport damaged cellular material, this eventually contributes to the spread of pathological misfolded proteins within the brain, thus promoting the neurodegeneration process. In this review, we focus on the role of exosomes in CNS homeostasis, their possible contribution to the development of neurodegenerative diseases, the usefulness of exosome cargo as biomarkers of disease, and the potential benefits of plasma circulating CNS-derived exosomes.

Synaptic Activity and (Neuro)Inflammation in Alzheimer's Disease: Could Exosomes be an Additional Link?

Nanosized extracellular vesicles, known as exosomes, are produced by all cell types in mammalian organisms and have been recently involved in neurodegeneration. In the brain, both glia and neurons give rise to exosomes, which contribute to their intercellular communication. In addition, brain-derived exosomes have a remarkable property to cross the blood-brain-barrier bi-directionally. In this line, exosomes of central origin have been identified in peripheral circulation and already considered as putative blood biomarkers of neurodegenerative diseases, including Alzheimer's disease (AD). Moreover, tentative use of exosomes as vehicle for the clearance of brain-born toxic proteins or, conversely, neuroprotective drug delivery, was also envisaged. However, little is known about the precise role of exosomes in the control and regulation of neuronal functions. Based on the presence of subunits of glutamate receptors in neuron-derived exosomes on one hand, and complement proteins in astrocyte-derived exosomes on the other hand, we hypothesize that exosomes may participate in the control of neuronal excitability via inflammatory-like mechanisms both at the central level and from the periphery. In this review, we will focus on AD and discuss the mechanisms by which exosomes of neuronal, glial, and/or peripheral origin could impact on neuronal excitability either directly or indirectly.

Hyperoxia-activated circulating extracellular vesicles induce lung and brain injury in neonatal rats

Hyperoxia-induced lung injury plays a key role in the development of bronchopulmonary dysplasia (BPD), characterized by inflammatory injury and impaired lung development in preterm infants. Although BPD is a predictor of poor neurodevelopmental outcomes, currently it is uncertain how lung injury contributes to brain injury in preterm infants. Extracellular vesicles (EVs) are a heterogeneous group of cell-derived membranous structures that regulate intercellular and inter-organ communications. Gasdermin D (GSDMD) has emerged as a key executor of inflammasome-mediated cell death and inflammation. In this study, we utilized a neonatal rat model of BPD to assess if hyperoxia stimulates lung release of circulating EVs and if these EVs induce lung and brain injury. We found that hyperoxia-exposed rats had elevated numbers of plasma-derived EVs compared to rats maintained in room air. These EVs also had increased cargos of surfactant protein C, a marker of type II alveolar epithelial cells (AEC), and the active (p30) form of GSDMD. When these EVs were adoptively transferred into normal newborn rats via intravenous injection, they were taken up both by lung and brain tissues. Moreover, EVs from hyperoxic animals induced not only the pathological hallmarks of BPD, but also brain inflammatory injury in recipient rats, as well as inducing cell death in cultured pulmonary vascular endothelial cells and neural stem cells (NSC). Similarly, hyperoxia-exposed cultured AEC-like cells released EVs that also contained increased GSDMD-p30 and these EVs induced pyroptotic cell death in NSC. Overall, these data indicate that hyperoxia-activated circulating EVs mediate a lung to brain crosstalk resulting in brain injury and suggest a mechanism that links lung injury and neurodevelopmental impairment in BPD infants.

The Emerging World of Membrane Vesicles: Functional Relevance, Theranostic Avenues and Tools for Investigating Membrane Function

Lipids are essential components of cell membranes and govern various membrane functions. Lipid organization within membrane plane dictates recruitment of specific proteins and lipids into distinct nanoclusters that initiate cellular signaling while modulating protein and lipid functions. In addition, one of the most versatile function of lipids is the formation of diverse lipid membrane vesicles for regulating various cellular processes including intracellular trafficking of molecular cargo. In this review, we focus on the various kinds of membrane vesicles in eukaryotes and bacteria, their biogenesis, and their multifaceted functional roles in cellular communication, host-pathogen interactions and biotechnological applications. We elaborate on how their distinct lipid composition of membrane vesicles compared to parent cells enables early and non-invasive diagnosis of cancer and tuberculosis, while inspiring vaccine development and drug delivery platforms. Finally, we discuss the use of membrane vesicles as excellent tools for investigating membrane lateral organization and protein sorting, which is otherwise challenging but extremely crucial for normal cellular functioning. We present current limitations in this field and how the same could be addressed to propel a fundamental and technology-oriented future for extracellular membrane vesicles.

Bacterial Extracellular Vesicles and the Gut-Microbiota Brain Axis: Emerging Roles in Communication and Potential as Therapeutics

Bacterial extracellular vesicles (BEVs) have emerged as candidate signaling vectors for long-distance interkingdom communication within the gut-microbiota brain axis. Most bacteria release these nanosized vesicles, capable of signaling to the brain via their abundant protein and small RNA cargo, possibly directly via crossing the blood-brain barrier. BEVs have been shown to regulate brain gene expression and induce pathology at most stages of neuroinflammation and neurodegeneration, and thus they may play a causal role in diseases such as Alzheimer's, Parkinson's, and depression/anxiety. On the other hand, BEVs have intrinsic therapeutic properties that may be relevant to probiotic therapy and can also be engineered to function as drug delivery vehicles and vaccines. Thus, BEVs may be both a cause of and solution to neuropathological conditions. In this review, current knowledge of the physiological roles of BEVs as well as state of the art pertaining to the development of therapeutic BEVs in the context of the microbiome-gut-brain axis are summarized.

Examining the evidence for extracellular RNA function in mammals

The presence of RNAs in the extracellular milieu has sparked the hypothesis that RNA may play a role in mammalian cell-cell communication. As functional nucleic acids transfer from cell to cell in plants and nematodes, the idea that mammalian cells also transfer functional extracellular RNA (exRNA) is enticing. However, untangling the role of mammalian exRNAs poses considerable experimental challenges. This Review discusses the evidence for and against functional exRNAs in mammals and their proposed roles in health and disease, such as cancer and cardiovascular disease. We conclude with a discussion of the forward-looking prospects for studying the potential of mammalian exRNAs as mediators of cell-cell communication.

Elucidating Methods for Isolation and Quantification of Exosomes: A Review

Exosomes are the smallest extracellular vesicles present in most of the biological fluids. They are found to play an important role in cell signaling, immune response, tumor metastasis, etc. Studies have shown that these vesicles also have diagnostic and therapeutic roles for which their accurate detection and quantification is essential. Due to the complexity in size and structure of exosomes, even the gold standard methods face challenges. This comprehensive review discusses the various standard methods such as ultracentrifugation, ultrafiltration, size-exclusion chromatography, precipitation, immunoaffinity, and microfluidic technologies for the isolation of exosomes. The principle of isolation of each method is described, as well as their specific advantages and disadvantages. Quantification of exosomes by nanoparticle tracking analysis, flow cytometry, tunable resistive pulse sensing, electron microscopy, dynamic light scattering, and microfluidic devices are also described, along with the applications of exosomes in various biomedical domains.

Socially Distanced Intercellular Communication: Mechanisms for Extracellular Vesicle Cargo Delivery

Extracellular vesicles (EVs) are increasingly being recognised as players in intercellular communication within the human body. EVs are nano-sized vesicles that are secreted by virtually all cells, primarily arising from either the plasma membrane or the endocytic system. They contain a wide range of proteins and nucleic acids in their lumen, as well as cell surface proteins on their exterior. The proteins and nucleic acids within are the 'cargo' that EVs deliver into the cytosol of recipient cells to elicit a response or phenotypic change. For delivery to occur, the cargo needs to cross two lipid bilayers; one that makes up the vesicle itself, and the other of the recipient cell. Exactly how this process works is a topic that is poorly understood, despite being pivotal for their function. Furthermore, extracellular vesicles have therapeutic potential as drug delivery vehicles. Therefore, understanding their delivery mechanism and harnessing its action for drug delivery is of great importance. This chapter will focus on the proposed mechanisms for cargo delivery and discuss existing evidence for cargo delivery from EVs into the cytosol of recipient cells.

Gliomas Interact with Non-glioma Brain Cells via Extracellular Vesicles

Emerging evidence suggests that crosstalk between glioma cells and the brain microenvironment may influence brain tumor growth. To date, known reciprocal interactions among these cells have been limited to the release of paracrine factors. Combining a genetic strategy with longitudinal live imaging, we find that individual gliomas communicate with distinct sets of non-glioma cells, including glial cells, neurons, and vascular cells. Transfer of genetic material is achieved mainly through extracellular vesicles (EVs), although cell fusion also plays a minor role. We further demonstrate that EV-mediated communication leads to the increase of synaptic activity in neurons. Blocking EV release causes a reduction of glioma growth in vivo. Our findings indicate that EV-mediated interaction between glioma cells and non-glioma brain cells alters the tumor microenvironment and contributes to glioma development.

Aptamer-Based Detection of Circulating Targets for Precision Medicine

The past decade has witnessed ongoing progress in precision medicine to improve human health. As an emerging diagnostic technique, liquid biopsy can provide real-time, comprehensive, dynamic physiological and pathological information in a noninvasive manner, opening a new window for precision medicine. Liquid biopsy depends on the sensitive and reliable detection of circulating targets (e.g., cells, extracellular vesicles, proteins, microRNAs) from body fluids, the performance of which is largely governed by recognition ligands. Aptamers are single-stranded functional oligonucleotides, capable of folding into unique tertiary structures to bind to their targets with superior specificity and affinity. Their mature evolution procedure, facile modification, and affinity regulation, as well as versatile structural design and engineering, make aptamers ideal recognition ligands for liquid biopsy. In this review, we present a broad overview of aptamer-based liquid biopsy techniques for precision medicine. We begin with recent advances in aptamer selection, followed by a summary of state-of-the-art strategies for multivalent aptamer assembly and aptamer interface modification. We will further describe aptamer-based micro-/nanoisolation platforms, aptamer-enabled release methods, and aptamer-assisted signal amplification and detection strategies. Finally, we present our perspectives regarding the opportunities and challenges of aptamer-based liquid biopsy for precision medicine.

RNAs on the Go: Extracellular Transfer in Insects with Promising Prospects for Pest Management

RNA-mediated pathways form an important regulatory layer of myriad biological processes. In the last decade, the potential of RNA molecules to contribute to the control of agricultural pests has not been disregarded, specifically via the RNA interference (RNAi) mechanism. In fact, several proofs-of-concept have been made in this scope. Furthermore, a novel research field regarding extracellular RNAs and RNA-based intercellular/interorganismal communication is booming. In this article, we review key discoveries concerning extracellular RNAs in insects, insect RNA-based cell-to-cell communication, and plant-insect transfer of RNA. In addition, we overview the molecular mechanisms implicated in this form of communication and discuss future biotechnological prospects, namely from the insect pest-control perspective.

Role of Extracellular Vesicles in the Diagnosis and Pathogenesis of Barrett's Esophagus: A Mini-Review

Esophageal adenocarcinoma (EAC) continues to be a significant public health problem with survival rates that have remained stagnant. Although the population at the highest risk for EAC, i.e., patients with Barrett's esophagus (BE) has been clearly defined, patients with EAC continue to do poorly due to advanced stage at diagnosis. The field of extracellular vesicles (EV) could have huge application for the management of patients with BE and EAC by allowing timely diagnosis, serial monitoring, and improved understanding of disease biology. EV are actively packaged and actively secreted vesicles and contain microRNAs, proteins, lipids, and DNA. The contents of EV have been shown to provide useful insights into cellular transformation and pro-oncogenic processes. Early work shows promise but suffers from a high degree of technical and biological variation. The current review not only summarizes the current knowledge about EV as diagnostic biomarkers and their role in disease progression of BE and EAC but also provides the reader practical guidance to devise future experiments to perform well-designed studies.

The Emerging Role of Exosomes in Oral Squamous Cell Carcinoma

Oral cancer constitutes approximately 2% of all cancers, while the most common type, oral squamous cell carcinoma (OSCC) represents 90% of oral cancers. Although the treatment of OSCC has improved recently, it still has a high rate of local recurrence and poor prognosis, with a 5-year survival rate of only 50%. Advanced stage OSCC tends to metastasize to lymph nodes. Thus, exploring new therapeutic strategies for OSCC is therefore an urgent priority. Exosomes, the small membrane vesicles derived from endosomes, have been detected in a wide array of bodily fluids. Exosomes contain a diversity of proteins, mRNAs, and non-coding RNAs, including microRNAs, long non-coding RNAs, piRNAs, circular RNAs, tsRNAs, and ribosomal RNAs, which are delivered to neighboring cells or even transported to distant sites. Exosomes have been associated with the tumorigenesis of OSCC, promote the proliferation, colonization, and metastasis of OSCC by transferring their contents to the target cells. Furthermore, exosomes are involved in the regulation of the tumor microenvironment to transform conditions favoring cancer progression in vivo. In this review, we summarize the crucial role of exosomes in the tumorigenesis and progression of OSCC and discuss the potential clinical application of exosomes in OSCC treatment.