Intercellular communication by extracellular vesicles and their microRNAs in asthma

Exosomes from Hypoxia-treated Mesenchymal Stem Cells: Promoting Neuroprotection in Ischemic Stroke Through miR-214-3p/PTEN Mechanism

Stroke stands as the second leading cause of death globally, surpassed only by ischemic heart disease. It accounts for 9% of total worldwide deaths. Given the swiftly evolving landscape, medical professionals and researchers are devoting increased attention to identifying more effective and safer treatments. Recent years have witnessed a focus on exosomes derived from mesenchymal stem cells cultivated under hypoxic conditions, referred to as Hypo-Exo. These specialized exosomes contain an abundance of components that facilitate the restoration of ischemic tissue, surpassing the content found in normal exosomes. Despite advancements, the precise role of Hypo-Exo in cases of cerebral ischemia remains enigmatic. Therefore, this study was designed to shed light on the potential efficacy of Hypo-Exo in stroke treatment. Our investigations unveiled promising outcomes, as the administration of Hypo-Exo led to improved behavioral deficits and reduced infarct areas in mice affected by ischemic conditions. Notably, these positive effects were hindered when Hypo-Exo loaded with anti-miR-214-3p were introduced, implying that the neuroprotective attributes of Hypo-Exo are reliant on miR-214-3p. This conclusion was substantiated by the high levels of miR-214-3p detected within Hypo-Exo. Furthermore, our examination of the ischemic penumbra zone revealed a gradual and sustained escalation in PTEN expression, a phenomenon effectively countered by Hypo-Exo treatment. Collectively, our findings suggest the existence of a regulatory pathway centered on miR-214-3p within Hypo-Exo. This pathway exerts a downregulating influence on the PTEN/Akt signaling pathway, thereby contributing to the amelioration of neurological function subsequent to ischemia-reperfusion events.

Exosomes in asthma: Underappreciated contributors to the pathogenesis and novel therapeutic tools

OBJECTIVE

Asthma, a chronic inflammatory disease with diverse pathomechanisms, presents challenges in developing personalized diagnostic and therapeutic approaches. This review aims to provide a comprehensive overview of the role of exosomes, small extracellular vesicles, in asthma pathophysiology and explores their potential as diagnostic biomarkers and therapeutic tools.

METHODS

A literature search was conducted to identify recent studies investigating the involvement of exosomes in asthma. The retrieved articles were analyzed to extract relevant information on the role of exosomes in maintaining lung microenvironment homeostasis, regulating inflammatory responses, and their diagnostic and therapeutic potential for asthma.

RESULTS

Exosomes secreted by various cell types, have emerged as crucial mediators of intercellular communication in healthy and diseased conditions. Evidence suggest that exosomes play a significant role in maintaining lung microenvironment homeostasis and contribute to asthma pathogenesis by regulating inflammatory responses. Differential exosomal content between healthy individuals and asthmatics holds promise for the development of novel asthma biomarkers. Furthermore, exosomes secreted by immune and nonimmune cells, as well as those detected in biofluids, demonstrate potential in promoting or regulating immune responses, making them attractive candidates for designing new treatment strategies for inflammatory conditions such as asthma.

CONCLUSION

Exosomes, with their ability to modulate immune responses and deliver therapeutic cargo, offer potential as targeted therapeutic tools in asthma management. Further research and clinical trials are required to fully understand the mechanisms underlying exosome-mediated effects and translate these findings into effective diagnostic and therapeutic strategies for asthma patients.

New approach methodologies to enhance human health risk assessment of immunotoxic properties of chemicals - a PARC (Partnership for the Assessment of Risk from Chemicals) project

As a complex system governing and interconnecting numerous functions within the human body, the immune system is unsurprisingly susceptible to the impact of toxic chemicals. Toxicants can influence the immune system through a multitude of mechanisms, resulting in immunosuppression, hypersensitivity, increased risk of autoimmune diseases and cancer development. At present, the regulatory assessment of the immunotoxicity of chemicals relies heavily on rodent models and a limited number of Organisation for Economic Co-operation and Development (OECD) test guidelines, which only capture a fraction of potential toxic properties. Due to this limitation, various authorities, including the World Health Organization and the European Food Safety Authority have highlighted the need for the development of novel approaches without the use of animals for immunotoxicity testing of chemicals. In this paper, we present a concise overview of ongoing efforts dedicated to developing and standardizing methodologies for a comprehensive characterization of the immunotoxic effects of chemicals, which are performed under the EU-funded Partnership for the Assessment of Risk from Chemicals (PARC).

Review of exosomes and their potential for veterinary medicine

Small extracellular vesicles called exosomes are released by almost all cell types and play a crucial role in both healthy and pathological circumstances. Exosomes, found in biological fluids (including plasma, urine, milk, semen, saliva, abdominal fluid and cervical vaginal fluid) and ranging in size from 50 to 150 nm, are critical for intercellular communication. Analysis of exosomal cargos, including micro RNAs (miRNAs), proteins and lipids, has been proposed as valuable diagnostic and prognostic biomarkers of disease. Exosomes can also be used as novel, cell-free, treatment strategies. In this review, we discuss the role, significance and application of exosomes and their cargos in diseases of animals.

Epigenetic regulation of pulmonary inflammation

Pulmonary disease such as chronic obstructive pulmonary disease (COPD), asthma, pulmonary fibrosis and pulmonary hypertension are the leading cause of deaths. More importantly, lung diseases are on the rise and environmental factors induced epigenetic modifications are major players on this increased prevalence. It has been reported that dysregulation of genes involved in epigenetic regulation such as the histone deacetylase (HDACs) and histone acetyltransferase (HATs) play important role in lung health and pulmonary disease pathogenesis. Inflammation is an essential component of respiratory diseases. Injury and inflammation trigger release of extracellular vesicles that can act as epigenetic modifiers through transfer of epigenetic regulators such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), proteins and lipids, from one cell to another. The immune dysregulations caused by the cargo contents are important contributors of respiratory disease pathogenesis. N6 methylation of RNA is also emerging to be a critical mechanism of epigenetic alteration and upregulation of immune responses to environmental stressors. Epigenetic changes such as DNA methylation are stable and often long term and cause onset of chronic lung conditions. These epigenetic pathways are also being utilized for therapeutic intervention in several lung conditions.

Air Pollution and microRNAs: The Role of Association in Airway Inflammation

Air pollution exposure plays a key role in the alteration of gene expression profiles, which can be regulated by microRNAs, inducing the development of various diseases. Moreover, there is also evidence of sensitivity of miRNAs to environmental factors, including tobacco smoke. Various diseases are related to specific microRNA signatures, suggesting their potential role in pathophysiological processes; considering their association with environmental pollutants, they could become novel biomarkers of exposure. Therefore, the aim of the present work is to analyse data reported in the literature on the role of environmental stressors on microRNA alterations and, in particular, to identify specific alterations that might be related to the development of airway diseases so as to propose future preventive, diagnostic, and therapeutic strategies.

The Role of microRNAs in Inflammation

Inflammation is a biological response of the immune system to various insults, such as pathogens, toxic compounds, damaged cells, and radiation. The complex network of pro- and anti-inflammatory factors and their direction towards inflammation often leads to the development and progression of various inflammation-associated diseases. The role of small non-coding RNAs (small ncRNAs) in inflammation has gained much attention in the past two decades for their regulation of inflammatory gene expression at multiple levels and their potential to serve as biomarkers and therapeutic targets in various diseases. One group of small ncRNAs, microRNAs (miRNAs), has become a key regulator in various inflammatory disease conditions. Their fine-tuning of target gene regulation often turns out to be an important factor in controlling aberrant inflammatory reactions in the system. This review summarizes the biogenesis of miRNA and the mechanisms of miRNA-mediated gene regulation. The review also briefly discusses various pro- and anti-inflammatory miRNAs, their targets and functions, and provides a detailed discussion on the role of miR-10a in inflammation.

Recent Advances in Nanomaterials for Asthma Treatment

Asthma is a chronic airway inflammatory disease with complex mechanisms, and these patients often encounter difficulties in their treatment course due to the heterogeneity of the disease. Currently, clinical treatments for asthma are mainly based on glucocorticoid-based combination drug therapy; however, glucocorticoid resistance and multiple side effects, as well as the occurrence of poor drug delivery, require the development of more promising treatments. Nanotechnology is an emerging technology that has been extensively researched in the medical field. Several studies have shown that drug delivery systems could significantly improve the targeting, reduce toxicity and improve the bioavailability of drugs. The use of multiple nanoparticle delivery strategies could improve the therapeutic efficacy of drugs compared to traditional delivery methods. Herein, the authors presented the mechanisms of asthma development and current therapeutic methods. Furthermore, the design and synthesis of different types of nanomaterials and micromaterials for asthma therapy are reviewed, including polymetric nanomaterials, solid lipid nanomaterials, cell membranes-based nanomaterials, and metal nanomaterials. Finally, the challenges and future perspectives of these nanomaterials are discussed to provide guidance for further research directions and hopefully promote the clinical application of nanotherapeutics in asthma treatment.

EVs-miRNA: The New Molecular Markers for Chronic Respiratory Diseases

Idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), asthma and sleep disorders are chronic respiratory diseases that affect the airways, compromising lung function over time. These diseases affect hundreds of millions of people around the world and their frequency seems to be increasing every year. Extracellular vesicles (EVs) are small-sized vesicles released by every cell in the body. They are present in most body fluids and contain various biomolecules including proteins, lipids, mRNA and non-coding RNA (micro-RNA). The EVs can release their cargo, specifically micro-RNAs (miRNAs), to both neighboring and/or distal cells, playing a fundamental role in cell-cell communication. Recent studies have shown their possible role in the pathogenesis of various chronic respiratory diseases. The expression of miRNAs and, in particular, of miRNAs contained within the extracellular vesicles seems to be a good starting point in order to identify new potential biomarkers of disease, allowing a non-invasive clinical diagnosis. In this review we summarize some studies, present in the literature, about the functions of extracellular vesicles and miRNAs contained in extracellular vesicles in chronic respiratory diseases and we discuss the potential clinical applications of EVs and EVs-miRNAs for their possible use such as future biomarkers.

Profile of circulating extracellular vesicles microRNA correlates with the disease activity in granulomatosis with polyangiitis

Granulomatosis with polyangiitis is a chronic systemic inflammation of small vessels characterized by circulating anti-proteinase 3 antibodies. MicroRNAs are short transcripts specifically inhibiting protein translation. Neutrophils can release extracellular vesicles (EVs). In this study, we characterized profile of microRNA trafficked by EVs in GPA. Fifty patients with GPA were enrolled in the study, 25 at acute phase and 25 in remission. EVs were isolated from the blood serum, characterized by their number, size distribution. Following unbiased screening for microRNA expression, differentially expressed candidates were measured by quantitative real-time PCR. Circulating DNA-myeloperoxidase complexes and apoptosis-related transcripts in peripheral blood neutrophils were quantified. We identified four differentially expressed microRNAs from EVs in granulomatosis with polyangiitis (GPA). MirRs-223-3p, 664a-3p, and 200b-3p were overexpressed and miR-769-5p suppressed in the disease. A distinction between GPA and healthy controls was the best for miR-223-3p, whereas miR-664a-3p discriminated between active vs. remission of GPA. Correct classification of the disease based on multivariate discriminant analysis was between 92% for acute phase and 85% for all study participants. Bioinformatics tools identified genes transcripts potentially targeted by the microRNAs belonging to pathways of focal adhesion, mTOR signaling and neutrophil extracellular traps formation. Two microRNAs positively correlating with the disease activity were involved in neutrophil extracellular traps formation and apoptosis inhibition. A comprehensive characteristics of microRNAs trafficked in bloodstream inside EVs correlates well with our understanding of the mechanisms of GPA and suggests the importance of EVs in progression of the disease.

Packaging and Delivery of Asthma Therapeutics

Asthma is a life-altering, chronic disease of heterogenous origin that features a complex interplay of immune and environmental signaling. Although very little progress has been made in prevention, diverse types of medications and delivery systems, including nanoscale systems, have been or are currently being developed to control airway inflammation and prevent exacerbations and fibrosis. These medications are delivered through mechanical methods, with various inhalers (with benefits and drawbacks) existing, and new types offering some variety in delivery. Of particular interest is the progress being made in nanosized materials for efficient penetration into the epithelial mucus layer and delivery into the deepest parts of the lungs. Liposomes, nanoparticles, and extracellular vesicles, both natural and synthetic, have been explored in animal models of asthma and have produced promising results. This review will summarize and synthesize the latest developments in both macro-(inhaler) and micro-sized delivery systems for the purpose of treating asthma patients.

microRNA-19b-3p-containing extracellular vesicles derived from macrophages promote the development of atherosclerosis by targeting JAZF1

Atherosclerosis has been regarded as a major contributor to cardiovascular disease. The role of extracellular vesicles (EVs) in the treatment of atherosclerosis has been increasingly reported. In this study, we set out to investigate the effect of macrophages‐derived EVs (M‐EVs) containing miR‐19b‐3p in the progression of atherosclerosis, with the involvement of JAZF1. Following isolation of EVs from macrophages, the M‐EVs were induced with ox‐low density lipoprotein (LDL) (ox‐LDL‐M‐EVs), and co‐cultured with vascular smooth muscle cells (VSMCs). RT‐qPCR and western blot assay were performed to determine the expression of miR‐19b‐3p and JAZF1 in M‐EVs and in VSMCs. Lentiviral infection was used to overexpress or knock down miR‐19b‐3p. EdU staining and scratch test were conducted to examine VSMC proliferation and migration. Dual‐luciferase gene reporter assay was performed to examine the relationship between miR‐19b‐3p and JAZF1. In order to explore the role of ox‐LDL‐M‐EVs carrying miR‐19b‐3p in atherosclerotic lesions in vivo, a mouse model of atherosclerosis was established through high‐fat diet induction. M‐EVs were internalized by VSMCs. VSMC migration and proliferation were promoted by ox‐LDL‐M‐EVs. miR‐19b‐3p displayed upregulation in ox‐LDL‐M‐EVs. miR‐19b‐3p was transferred by M‐EVs into VSMCs, thereby promoting VSMC migration and proliferation. mir‐19b‐3p targeted JAZF1 to decrease its expression in VSMCs. Atherosclerosis lesions were aggravated by ox‐LDL‐M‐EVs carrying miR‐19b‐3p in ApoE^−/− mice. Collectively, this study demonstrates that M‐EVs containing miR‐19b‐3p accelerate migration and promotion of VSMCs through targeting JAZF1, which promotes the development of atherosclerosis.

Extracellular Vesicles Derived From Citrus sinensis Modulate Inflammatory Genes and Tight Junctions in a Human Model of Intestinal Epithelium

It is widely acknowledged that mammalian exosomes (or extracellular vesicles), have a key role in intercellular communication, owing to the presence of various bioactive molecules such as lipids, proteins, and microRNAs within their inner compartment. Most recently, the discovery of extracellular vesicles isolated from edible plants (such as vegetables and fruits) and their similarity in terms of size and content with exosomes has opened new perspectives on possible intercellular communication and regulation of important biological processes in which these vesicles are involved. It is also well-known that a balanced diet rich of fruits and vegetables (i.e., the Mediterranean diet) can contribute to maintain a “healthy gut” by preserving the intestinal epithelial barrier integrity and avoid that inflammatory stimuli that can alter homeostasis. In our study, we optimized a method to isolate extracellular vesicles from the orange juice (Citrus sinensis) (CS-EVs), and we characterized their morphology and behavior when in contact with the intestinal epithelium. We showed that CS-EVs are stable in a simulated gastrointestinal environment and are absorbed by intestinal cells without toxic effects, as expected. Furthermore, we demonstrated that CS-EVs can alter the gene expression of several genes involved in inflammation (i.e., ICAM1 and HMOX-1) and tight junctions (i.e., OCLN, CLDN1, and MLCK), contributing to limit inflammatory stimuli and restore a functional barrier by increasing the tight junction OCLN protein. Therefore, our study emphasizes the relevant role of fruit-derived extracellular vesicles in modulating important biological processes and maintaining a healthy intestinal epithelium, ultimately promoting human health and well-being.

Sensing and imaging of exosomal CD26 secreted from cancer cells and 3D colorectal tumor model using a novel near-infrared fluorogenic probe

Cancer-derived exosomes or their specific components hold great promise for early diagnosis and precise staging of cancers. This work aimed to construct a novel enzyme-activatable fluorescent substrate for real-time detection and in situ imaging of a key exosomal surface protein CD26 in various biological systems, as well as to reveal the relevance of exosomal CD26 to the tumorigenesis. For these purposes, a group of Gly-Pro amides deriving from several near-infrared fluorophores were designed on the basis of the unique prolyl-cleaving dipeptidease activity of CD26, while molecular docking simulations were applied to assess the possibility of the designed amides as CD26 specific substrates. Following virtual screening and experimental validation, it was observed that GP-ACM displayed the best combination of high sensitivity and excellent specificity to CD26. The sensing and imaging ability of GP-ACM towards CD26 were examined in a range of biological systems, such as living cells, in situ tissues, and the exosomes secreted from cancer cells. Under physiological conditions, GP-ACM can be readily hydrolyzed by CD26 to release the fluorescent product ACM. The fluorescent product emits strong near-infrared fluorescence signals around 660 nm, which can be easily captured by the devices equipped with a fluorescence detector. GP-ACM prolyl-cleaving reaction shows excellent specificity and rapid response towards CD26, while its fluorescent product ACM displays good chemical stability and outstanding photostability. With the help of GP-ACM, CD26 in living cells, tissues and the tumor-secreted exosomes can be real-time monitored and in-situ imaged, while further investigations reveal that the exosomal CD26 activities are abnormally elevated with the progression of colon tumor. Collectively, the present study offers a practical optical assay for real-time monitoring CD26 activities in multiple complex biological systems including the exosomes secreted by tumor cells. The simplicity and effectiveness of this assay hold great potential for facilitating fundamental researches and clinical diagnosis of exosomal CD26 associated diseases.

Extracellular Vesicles in Airway Homeostasis and Pathophysiology

The epithelial–mesenchymal trophic unit (EMTU) is a morphofunctional entity involved in the maintenance of the homeostasis of airways as well as in the pathogenesis of several diseases, including asthma and chronic obstructive pulmonary disease (COPD). The “muco-microbiotic layer” (MML) is the innermost layer of airways made by microbiota elements (bacteria, viruses, archaea and fungi) and the surrounding mucous matrix. The MML homeostasis is also crucial for maintaining the healthy status of organs and its alteration is at the basis of airway disorders. Nanovesicles produced by EMTU and MML elements are probably the most important tool of communication among the different cell types, including inflammatory ones. How nanovesicles produced by EMTU and MML may affect the airway integrity, leading to the onset of asthma and COPD, as well as their putative use in therapy will be discussed here.

Inflammation in Asthma Pathogenesis: Role of T cells, Macrophages, Epithelial Cells and Type 2 Inflammation

Asthma is a chronic disease with abnormal inflammatory and immunological responses. The disease initiated by antigens in subjects with genetic susceptibility. However, environmental factors play a role in the initiation and exacerbation of asthma attack. Asthma is T helper 2 (Th2)-cell-mediated disease. Recent studies indicated that asthma is not a single disease entity, but it is with multiple phenotypes and endotypes. The pathophysiological changes in asthma included a series of subsequent continuous vicious circle of cellular activation contributed to induction of chemokines and cytokines that potentiate inflammation. The heterogeneity of asthma influenced the treatment response. The asthma pathogenesis driven by varied set of cells such as eosinophils, basophils, neutrophils, mast cells, macrophages, epithelial cells and T cells. In this review the role of T cells, macrophage, and epithelial cells are discussed.

Potential Therapeutic Effect of Micrornas in Extracellular Vesicles from Mesenchymal Stem Cells against SARS-CoV-2

Extracellular vesicles (EVs) are cell-released, nanometer-scaled, membrane-bound materials and contain diverse contents including proteins, small peptides, and nucleic acids. Once released, EVs can alter the microenvironment and regulate a myriad of cellular physiology components, including cell–cell communication, proliferation, differentiation, and immune responses against viral infection. Among the cargoes in the vesicles, small non-coding micro-RNAs (miRNAs) have received attention in that they can regulate the expression of a variety of human genes as well as external viral genes via binding to the complementary mRNAs. In this study, we tested the potential of EVs as therapeutic agents for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. First, we found that the mesenchymal stem-cell-derived EVs (MSC-EVs) enabled the rescue of the cytopathic effect of SARS-CoV-2 virus and the suppression of proinflammatory responses in the infected cells by inhibiting the viral replication. We found that these anti-viral responses were mediated by 17 miRNAs matching the rarely mutated, conserved 3′-untranslated regions (UTR) of the viral genome. The top five miRNAs highly expressed in the MSC-EVs, miR-92a-3p, miR-26a-5p, miR-23a-3p, miR-103a-3p, and miR-181a-5p, were tested. They were bound to the complemented sequence which led to the recovery of the cytopathic effects. These findings suggest that the MSC-EVs are a potential candidate for multiple variants of anti-SARS-CoV-2.

The role of exosomes from BALF in lung disease

Exosomes are released from a variety of immune cells and nonimmune cells, the phospholipid vesicle bilayer membrane structure actively secreted into tissues. Recently, exosomes were demonstrated to be effectively delivered proteins, cholesterol, lipids, and amounts of DNA, mRNA, and noncoding RNAs to a target cell or tissue from a host cell. These can be detected in blood, urine, exhaled breath condensates, bronchoalveolar lavage fluid (BALF), ascites, and cerebrospinal fluid. BALF is a clinical examination method for obtaining alveolar cells and biochemical components, reflecting changes in the lungs, so it is also called liquid biopsy. Exosomes from BALF become a new method for intercellular communication and well‐documented in various pulmonary diseases. In chronic obstructive pulmonary disease (COPD), BALF exosomes can predict the degree of COPD damage and serve as an effective monitoring indicator for airflow limitation and airway remodeling. It also mediates antigen presentation in the airways to the adaptive immune system as well as costimulatory effects. Furthermore, BALF exosomes from acute lung injury and infective diseases are closely related to various infections and lack of oxygen status. BALF exosomes play an important role in the diagnosis and prognosis of lung cancer. The effect of immunomodulatory role for BALF exosomes in adaptive and innate immune responses has been studied in sarcoidosis. The intercellular communication in the microenvironment of BALF exosomes in pulmonary fibrosis and lung remodeling have been studied. In this review, we summarize the novel findings of exosomes in BALF, executed function by protein, miRNA, DNA cytokine, and so on in several pulmonary diseases.

Extracellular Vesicles as Potential Therapeutics for Inflammatory Diseases

Extracellular vesicles (EV) deliver cargoes such as nucleic acids, proteins, and lipids between cells and serve as an intercellular communicator. As it is revealed that most of the functions associated to EVs are closely related to the immune response, the important role of EVs in inflammatory diseases is emerging. EVs can be functionalized through EV surface engineering and endow targeting moiety that allows for the target specificity for therapeutic applications in inflammatory diseases. Moreover, engineered EVs are considered as promising nanoparticles to develop personalized therapeutic carriers. In this review, we highlight the role of EVs in various inflammatory diseases, the application of EV as anti-inflammatory therapeutics, and the current state of the art in EV engineering techniques.

Asthmatic condition induced the activity of exosome secretory pathway in rat pulmonary tissues

BACKGROUND

The recent studies highlighted the critical role of exosomes in the regulation of inflammation. Here, we investigated the dynamic biogenesis of the exosomes in the rat model of asthma.

RESULTS

Our finding showed an increase in the expression of IL-4 and the suppression of IL-10 in asthmatic lung tissues compared to the control samples (p < 0.05). Along with the promotion of IL-4, the protein level of TNF-α was induced, showing an active inflammatory status in OVA-sensitized rats. According to our data, the promotion of asthmatic responses increased exosome biogenesis indicated by increased CD63 levels and acetylcholine esterase activity compared to the normal condition (p < 0.05).

CONCLUSION

Data suggest that the stimulation of inflammatory response in asthmatic rats could simultaneously increase the paracrine activity of pulmonary cells via the exosome biogenesis. Exosome biogenesis may correlate with the inflammatory response.

MicroRNAs as Potential Regulators of Immune Response Networks in Asthma and Chronic Obstructive Pulmonary Disease

Chronic respiratory diseases (CRDs) are an important factor of morbidity and mortality, accounting for approximately 6% of total deaths worldwide. The main CRDs are asthma and chronic obstructive pulmonary disease (COPD). These complex diseases have different triggers including allergens, pollutants, tobacco smoke, and other risk factors. It is important to highlight that although CRDs are incurable, various forms of treatment improve shortness of breath and quality of life. The search for tools that can ensure accurate diagnosis and treatment is crucial. MicroRNAs (miRNAs) are small non-coding RNAs and have been described as promising diagnostic and therapeutic biomarkers for CRDs. They are implicated in multiple processes of asthma and COPD, regulating pathways associated with inflammation, thereby showing that miRNAs are critical regulators of the immune response. Indeed, miRNAs have been found to be deregulated in several biofluids (sputum, bronchoalveolar lavage, and serum) and in both structural lung and immune cells of patients in comparison to healthy subjects, showing their potential role as biomarkers. Also, miRNAs play a part in the development or termination of histopathological changes and comorbidities, revealing the complexity of miRNA regulation and opening up new treatment possibilities. Finally, miRNAs have been proposed as prognostic tools in response to both conventional and biologic treatments for asthma or COPD, and miRNA-based treatment has emerged as a potential approach for clinical intervention in these respiratory diseases; however, this field is still in development. The present review applies a systems biology approach to the understanding of miRNA regulatory networks in asthma and COPD, summarizing their roles in pathophysiology, diagnosis, and treatment.

Influence of microRNAs and exosomes in muscle health and diseases

microRNAs are short, (18-22 nt) non-coding RNAs involved in important cellular processes due to their ability to regulate gene expression at the post-transcriptional level. Exosomes are small (50-200 nm) extracellular vesicles, naturally secreted from a variety of living cells and are believed to mediate cell-cell communication through multiple mechanisms, including uptake in destination cells. Circulating microRNAs and exosome-derived microRNAs can have key roles in regulating muscle cell development and differentiation. Several microRNAs are highly expressed in muscle and their regulation is important for myocyte homeostasis. Changes in muscle associated microRNA expression are associated with muscular diseases including muscular dystrophies, inflammatory myopathies, and congenital myopathies. In this review, we aim to highlight the biology of microRNAs and exosomes as well as their roles in muscle health and diseases. We also discuss the potential crosstalk between skeletal and cardiac muscle through exosomes and their contents.

The Role of T Cells and Macrophages in Asthma Pathogenesis: A New Perspective on Mutual Crosstalk

Asthma is associated with innate and adaptive immunity mediated by immune cells. T cell or macrophage dysfunction plays a particularly significant role in asthma pathogenesis. Furthermore, crosstalk between them continuously transmits proinflammatory or anti-inflammatory signals, causing the immune cell activation or repression in the immune response. Consequently, the imbalanced immune microenvironment is the major cause of the exacerbation of asthma. Here, we discuss the role of T cells, macrophages, and their interactions in asthma pathogenesis.

Extracellular vesicles: novel communicators in lung diseases

The lung is the organ with the highest vascular density in the human body. It is therefore perceivable that the endothelium of the lung contributes significantly to the circulation of extracellular vesicles (EVs), which include exosomes, microvesicles, and apoptotic bodies. In addition to the endothelium, EVs may arise from alveolar macrophages, fibroblasts and epithelial cells. Because EVs harbor cargo molecules, such as miRNA, mRNA, and proteins, these intercellular communicators provide important insight into the health and disease condition of donor cells and may serve as useful biomarkers of lung disease processes. This comprehensive review focuses on what is currently known about the role of EVs as markers and mediators of lung pathologies including COPD, pulmonary hypertension, asthma, lung cancer and ALI/ARDS. We also explore the role EVs can potentially serve as therapeutics for these lung diseases when released from healthy progenitor cells, such as mesenchymal stem cells.

Importance of microbial extracellular vesicle in the pathogenesis of asthma and chronic obstructive pulmonary disease and its diagnostic potential

There are rising evidences of the human microbiome as a potentially influential player that is actively engaged in shaping the pathogenetic processes and other unresolved issues both in asthma and other chronic respiratory diseases, particularly of the airways. The biological components such as microbiome in inhaled air can induce immune dysfunction and inflammation, leading to inflammatory pulmonary disorders such as asthma and chronic obstructive pulmonary disease (COPD). Microbe-derived extracellular vesicles (EVs) with biologically active information or functions can reprogram their respective target cells and EV may have a role for the development of asthma and COPD. To evaluate the role of microbe-derived EV in the pathogenesis of asthma and COPD and its role in diagnosis, the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement method was used for the study. An electronic search was performed using PubMed, PubMed Central, and Embase up to 2020. EVs serve as an intercellular transporter of miRNAs for cell-to-cell communication in the lungs. Bacteria-derived EVs have distinctive characteristics in the lungs of patients with asthma and COPD compared to healthy controls. Furthermore, bacterial EV IgG antibody titers in serum were significantly higher in patients with asthma and COPD than in healthy controls, suggesting that antibacterial EV antibodies titers can be used as a diagnostic tool for lung disease. Taken together, microbial EVs and miRNAs have important roles in the pathogenesis of asthma and COPD and they can provide novel diagnostic biomarkers for asthma and COPD.

Approaches to inducing antigen-specific immune tolerance in allergy and autoimmunity: Focus on antigen-presenting cells and extracellular vesicles

Increasing prevalence of allergic and autoimmune diseases urges clinicians and researchers to search for new and efficient treatments. Strategies that activate antigen-specific immune tolerance and simultaneously maintain immune reactivity to all other antigens deserve special attention. Accordingly, antigen-presenting cells (APCs) seem to be the best suited for orchestrating these mechanisms by directing T cell immune responses towards a tolerant subtype. Recent advances in understanding cell-to-cell communication via extracellular vesicles (EVs) make the latter promising candidates for reprogramming APCs towards a tolerant phenotype, and for mediating tolerogenic APC function. Thus, comprehensive studies have been undertaken to describe the interactions of APCs and EVs naturally occurring during immune tolerance induction, as well as to develop EV-based manoeuvres enabling the induction of immune tolerance in an antigen-specific manner. In this review, we summarize the findings of relevant studies, with a special emphasis on future perspectives on their translation to clinical practice.

The impact of microRNAs on alterations of gene regulatory networks in allergic diseases

Allergic diseases including asthma are worldwide on the rise and contribute significantly to health expenditures. Allergic diseases are prototypic diseases with a strong gene by environment interaction component and epigenetic mechanisms might mediate the effects of the environment on the disease phenotype. MicroRNAs, small non-coding RNAs (miRNAs), regulate gene expression post-transcriptionally. Functional single-stranded miRNAs are generated in multiple steps of enzymatic processing from their precursors and mature miRNAs are included into the RNA-induced silencing complex (RISC). They imperfectly base-pair with the 3'UTR region of targeted genes leading to translational repression or mRNA decay. The cellular context and microenvironment as well the isoform of the mRNA control the dynamics and complexity of the regulatory circuits induced by miRNAs that regulate cell fate decisions and function. MiR-21, miR-146a/b and miR-155 are among the best understood miRNAs of the immune system and implicated in different diseases including allergic diseases. MiRNAs are implicated in the induction of the allergy reinforcing the Th2 phenotype (miR-19a, miR-24, miR-27), while other miRNAs promote regulatory T cells associated with allergen tolerance or unresponsiveness. In the current chapter we describe in detail the biogenesis and regulatory function of miRNAs and summarize current knowledge on miRNAs in allergic diseases and allergy relevant cell fate decisions focusing mainly on immune cells. Furthermore, we evoke the principles of regulatory loops and feedback mechanisms involving miRNAs on examples with relevance for allergic diseases. Finally, we show the potential of miRNAs and exosomes containing miRNAs present in several biological fluids that can be exploited with non-invasive procedures for diagnostic and potentially therapeutic purposes.

Small RNA Sequencing Reveals Exosomal miRNAs Involved in the Treatment of Asthma by Scorpio and Centipede

Asthma is a common respiratory disease with inflammation in the lungs. Exosomes and microRNAs (miRNAs) play crucial role in inflammation, whereas the role of exosomal miRNA in asthma remains unknown. Here, we aimed to identify the key exosomal miRNAs and their underlying mechanisms involved in scorpio and centipede (SC) treatment in asthma. Eighteen mice were randomly divided into three groups: control group, asthma group, and SC treatment group. Effect of SC was assessed by hematoxylin-eosin staining and real-time PCR. Exosomes from asthma and SC treatment groups were analyzed by small RNA-seq. Results revealed SC significantly alleviated the pathogenesis of asthma and suppressed the release of inflammatory cytokines. A total of 328 exosomal miRNAs were differentially expressed between the exosomes from asthma and SC-treated mice, including 118 up- and 210 downregulated in SC-treated mice. The altered exosomal miRNAs were primarily involved in the function of transcription, apoptotic process, and cell adhesion; and pathway of calcium, Wnt, and MAPK signaling. Real-time PCR verified exosomal miR-147 was downregulated, while miR-98-5p and miR-10a-5p were upregulated in SC-treated mice compared to asthma mice. Moreover, the target genes of miR-147-3p, miR-98-5p, and miR-10a-5p were mainly enriched in Wnt and MAPK inflammatory signaling. miR-10a-5p promoted the proliferation of mouse lung epithelial cells and downregulated the expression of Nfat5 and Map2k6. These data suggest SC-induced exosomal miRNAs might mediate the inflammatory signaling and might be involved in the SC treatment in asthma. The exosomal miRNAs might be promising candidates for the treatment of asthma.

The potential of exosomes as theragnostics in various clinical situations

Exosomes are membrane-bound cargo measuring 30–140 nm comprised of a lipid bilayer containing various proteins, RNAs, DNAs, and bioactive lipids that can be transferred between cells. They have been shown to be produced and released by many different types of healthy and diseased cells. Exosomes are secreted by all types of cells in culture, and are also found in various body fluids including blood, saliva, urine, and breast milk. Exosomes are essential for healthy physiological as well as pathological processes. In addition to their normal function, exosomes are involved in the development and progression of various diseases, potentiating cellular stress and damage. Pathogens take advantage of exosome release from infected host cells by manipulating host-derived exosomes to evade the immune system responses. Exosomes are involved in other pathological conditions such as neurodegenerative diseases, liver diseases, heart failure, cancer, diabetes, kidney diseases, osteoporosis and atherosclerotic cardiovascular disease. Hence, we can exploit exosomes as biomarkers and vaccines and modify them rationally for therapeutic interventions including tissue engineering. Further studies on exosomes will explore their potential and provide new methodology for effective clinical diagnostics and therapeutic strategies: such uses can be called exosome theragnostics. This chapter reviews the potential theragnostic (diagnostic and therapeutic) application of exosomes in major organ systems in clinical fields.

The roles of exosomal miRNAs and lncRNAs in lung diseases

An increasing number of studies have reported that exosomes released from various cells can serve as mediators of information exchange between different cells. With further exploration of exosome content, a more accurate molecular mechanism involved in the process of cell-to-cell communication has been revealed; specifically, microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are shuttled by exosomes. In addition, exosomal miRNAs and lncRNAs may play vital roles in the pathogenesis of several respiratory diseases, such as chronic obstructive pulmonary disease (COPD), lung cancer, and asthma. Consequently, exosomal miRNAs and lncRNAs show promise as diagnostic biomarkers and therapeutic targets in several lung diseases. This review will summarize recent knowledge about the roles of exosomal miRNAs and lncRNAs in lung diseases, which has shed light on the discovery of novel diagnostic methods and treatments for these disorders. Because there is almost no published literature about exosomal lncRNAs in COPD, asthma, interstitial lung disease, or tuberculosis, we summarize the roles of exosomal lncRNAs only in lung cancer in the second section. This may inspire some new ideas for researchers who are interested in whether lncRNAs shuttled by exosomes may play roles in other lung diseases.

The Differential Expression Profiles of miRNA-let 7a, 7b, and 7c in Bronchoalveolar Lavage Fluid From Infants With Asthma and Airway Foreign Bodies

The aim of this study was to investigate the expression patterns of miRNA-let 7a, 7b, and 7c in bronchoalveolar lavage fluid in infants with asthma and airway foreign bodies. Between January 2016 and February 2017, 27 infants were included and divided into observation group (infants with asthma, n = 15) and control group (infants with airway foreign bodies, n = 12). The differential expression profiles of miRNA-let 7a, 7b, and 7c were determined by reverse transcription–polymerase chain reaction in bronchoalveolar lavage fluid (BALF) from infants of the 2 groups. The BALF was collected from infants undergoing flexible bronchoscopy. MiRNA-let 7a, 7b, and 7c increased significantly in infants from observation group as compared with control group (2.72 ± 0.48 vs 1, 8.23 ± 1.64 vs 1, 3.16 ± 0.62 vs 1, respectively). The increased expression of miRNA-let 7a, 7b, and 7c were associated with the asthma of infants.

An electrochemiluminescent aptasensor for amplified detection of exosomes from breast tumor cells (MCF-7 cells) based on G-quadruplex/hemin DNAzymes

Exosomes are non-invasive biomarkers for cancer diagnosis. Herein, we describe an electrochemiluminescent (ECL) aptasensor for the detection of exosomes from breast tumor cells. Mercaptopropionic acid (MPA)-modified Eu³⁺-doped CdS nanocrystals (MPA-CdS:Eu NCs) and H₂O₂ were used as ECL emitters and coreactant, respectively. The exosomes are recognized and captured by the CD63 aptamer, and then form a G-quadruplex/hemin DNAzyme, which efficiently catalyzes the decomposition of H₂O₂, resulting in the decreased ECL signal of MPA-CdS:Eu NCs. The exosomes from breast tumor cells (MCF-7 cells) can be detected in the range of 3.4 × 10⁵ to 1.7 × 10⁸ particles per mL. The limit of detection (LOD) was estimated to be 7.41 × 10⁴ particles per mL at a signal-to-noise ratio of 3. The aptasensor has been successfully used to detect exosomes in the serum.

Extracellular vesicles in lung health, disease, and therapy

Both physiological homeostasis and pathological disease processes in the lung typically result from complex, yet coordinated multicellular responses that are synchronized via paracrine and endocrine intercellular communication pathways. Of late, extracellular vesicles have emerged as important information shuttles that can coordinate and disseminate homeostatic and disease signals. In parallel, extracellular vesicles in biological fluids such as sputum, mucus, epithelial lining fluid, edema fluid, the pulmonary circulation, pleural fluid, and lymphatics have emerged as promising candidate biomarkers for diagnosis and prognosis in lung disease. Extracellular vesicles are small, subcellular, membrane-bound vesicles containing cargos from parent cells such as lipids, proteins, genetic information, or entire organelles. These cargos endow extracellular vesicles with biologically active information or functions by which they can reprogram their respective target cells. Recent studies show that extracellular vesicles found in lung-associated biological fluids play key roles as biomarkers and effectors of disease. Conversely, administration of naïve or engineered extracellular vesicles with homeostatic or reparative effects may provide a promising novel protective and regenerative strategy to treat lung disease. To highlight this rapidly developing field, the American Journal of Physiology-Lung Cellular and Molecular Physiology is now launching a special Call for Papers on extracellular vesicles in lung health, disease, and therapy. This review aims to set the stage for this call by introducing extracellular vesicles and their emerging roles in lung physiology and pathobiology.

Exosomes-the enigmatic regulators of bone homeostasis

Exosomes are a heterogeneous group of cell-derived membranous structures, which mediate crosstalk interaction between cells. Recent studies have revealed a close relationship between exosomes and bone homeostasis. It is suggested that bone cells can spontaneously secret exosomes containing proteins, lipids and nucleic acids, which then to regulate osteoclastogenesis and osteogenesis. However, the network of regulatory activities of exosomes in bone homeostasis as well as their therapeutic potential in bone injury remain largely unknown. This review will detail and discuss the characteristics of exosomes, the regulatory activities of exosomes in bone homeostasis as well as the clinical potential of exosomes in bone injury.

Vesicles known as exosomes may prove to be valuable clinical tools once their function is clarified. Exosomes were discovered in the 1980s but not observed in bone tissue until 2003. Minghao Zheng of the University of Western Australia, together with colleagues elsewhere, has reviewed the biology of exosomes, their role in maintaining bones, and their potential clinical uses. Exosomes carry lipids, proteins, and nucleic acids between cells. They are released by every type of bone cell, with the role of each exosome determined by its specific contents. Exosome-mediated crosstalk is involved in regulating bone remodeling, and exosomes have also been implicated in myelomas. Recent work has shown that exosome treatment can improve fracture healing. The authors conclude that a better understanding of the role of exosomes in bone homeostasis will unlock their significant clinical potential.

Exosomes from Thymic Stromal Lymphopoietin-Activated Dendritic Cells Promote Th2 Differentiation through the OX40 Ligand

OBJECTIVES

Exosomes are extracellular vesicles released from various inflammatory cells, such as T cells, B cells, dendritic cells (DCs), and mast cells, which have been implicated in the modulation of immune response in asthma. This study aimed to investigate whether exosomes from DCs activated by thymic stromal lymphopoietin (TSLP) play a role in T-helper cell differentiation through the OX40 ligand (OX40L).

METHODS

Serum samples from patients with asthma were collected to measure the levels of OX40L, T-helper type 1 (Th1) cytokine interferon (IFN)-γ, and T-helper type 2 (Th2) cytokine interleukin (IL)-4 by enzyme-linked immunosorbent assay (ELISA). Exosomes were isolated from TSLP-activated DCs and co-cultured with CD4+ T cells. Western blot and ELISA assays were used to measure the levels of OX40L, IFN-γ, and IL-4 in DCs and CD4+ T cells. Flow cytometry was applied to detect Th1 and Th2 cells.

RESULTS

OX40L and IL-4 were increased and IFN-γ was decreased in serum from asthmatic patients compared with healthy controls. TSLP induced DCs to express OX40L in released exosomes, which could promote proliferation of CD4+ T cells, elevate the level of IL-4, and promote Th2 differentiation.

CONCLUSION

Blockade of OX40L in DC-derived exosomes could inhibit exosome-mediated CD4+ T proliferation and Th2 differentiation.

Endothelial Extracellular Vesicles in Pulmonary Function and Disease

The pulmonary vascular endothelium is involved in the pathogenesis of acute and chronic lung diseases. Endothelial cell (EC)-derived products such as extracellular vesicles (EVs) serve as EC messengers that mediate inflammatory as well as cytoprotective effects. EC-EVs are a broad term, which encompasses exosomes and microvesicles of endothelial origin. EVs are comprised of lipids, nucleic acids, and proteins that reflect not only the cellular origin but also the stimulus that triggered their biogenesis and secretion. This chapter presents an overview of the biology of EC-EVs and summarizes key findings regarding their characteristics, components, and functions. The role of EC-EVs is specifically delineated in pulmonary diseases characterized by endothelial dysfunction, including pulmonary hypertension, acute respiratory distress syndrome and associated conditions, chronic obstructive pulmonary disease, and obstructive sleep apnea.

Extracellular vesicles are increased in the serum of children with autism spectrum disorder, contain mitochondrial DNA, and stimulate human microglia to secrete IL-1β

Background

Autism spectrum disorder (ASD) has been associated with brain inflammation as indicated by the activation of microglia, but the triggers are not known. Extracellular vesicles (EVs) are secreted from many cells in the blood and other biological fluids and carry molecules that could influence the function of target cells. EVs have been recently implicated in several diseases, but their presence or function in ASD has not been studied.

Methods

EVs were isolated from the serum of children with ASD (n = 20, 16 males and 4 females, 4–12 years old) and unrelated age and sex-matched normotypic controls (n = 8, 6 males and 2 females, 4–12 years old) using the exoEasy Qiagen kit. EVs were characterized by determining the CD9 and CD81 membrane-associated markers with Western blot analysis, while their morphology and size were assessed by transmission electron microscopy (TEM). Human microglia SV40 were cultured for 24 h and then stimulated with EVs (1 or 5 μg/mL), quantitated as total EV-associated protein, for 24 or 48 h. IL-1β secretion was measured by ELISA. The results were analyzed using the Mann-Whitney U non-parametric test, and all statistical analyses were performed using Graph Pad Prism 5.

Results

EVs were isolated and shown to be spherical structures (about 100 nm) surrounded by a membrane. Total EV-associated protein was found to be significantly increased (p = 0.02) in patients as compared to normotypic controls. EVs (5 μg/mL) isolated from the serum of patients with ASD stimulated cultured human microglia to secrete significantly more of the pro-inflammatory cytokine interleukin IL-1β (163.5 ± 13.34 pg/mL) as compared to the control (117.7 ± 3.96 pg/mL, p < 0.0001). The amount of mitochondrial DNA (mtDNA7S) contained in EVs from children with ASD was found to be increased (p = 0.046) compared to the normotypic controls.

Conclusions

These findings provide novel information that may help explain what triggers inflammation in the brain of children with ASD and could lead to novel effective treatments.

Exosomes and exosomal miRNAs from muscle-derived fibroblasts promote skeletal muscle fibrosis

Exosomes, natural carriers of mRNAs, non-coding RNAs and proteins between donor and recipient cells, actively contribute to cell-cell communication. We investigated the potential pro-fibrotic role of exosomes released by muscle-derived fibroblasts of Duchenne muscular dystrophy (DMD) patients, and of miRNAs carried by exosomes. By fibrosis focused array analysis we found that exosomes from DMD fibroblasts, had significantly higher levels of miR-199a-5p, a miRNA up-regulated in fibrotic conditions, compared to control exosomes, while levels in myoblast-derived exosomes were not increased. In control fibroblasts, exposure to DMD fibroblast-derived exosomes induced a myofibroblastic phenotype with increase in α-smooth actin, collagen and fibronectin transcript and protein expression, soluble collagen production and deposition, cell proliferation, and activation of Akt and ERK signaling, while exposure to control exosomes did not. Transfecting control fibroblasts or loading control exosomes with miR-199a-5p mimic or inhibitor induced opposing effects on fibrosis-related mRNAs and proteins, on collagen production and Akt and ERK pathways. Finally, injection of DMD fibroblast-derived exosomes into mouse tibialis anterior muscle after cardiotoxin-induced necrosis, produced greater fibrosis than control exosomes. Our findings indicate that exosomes produced by local fibroblasts in the DMD muscle are able to induce phenotypic conversion of normal fibroblasts to myofibroblasts thereby increasing the fibrotic response. This conversion is related to transfer of high levels of miR-199a-5p and to reduction of its target caveolin-1; both, therefore, are potential therapeutic targets in muscle fibrosis.

Exosomes in Severe Asthma: Update in Their Roles and Potential in Therapy

Exosomes are nanosized vesicles and have recently been recognized as important players in cell-to-cell communication. Exosomes contain different mediators such as proteins, nucleic acids (DNA, mRNA, miRNAs, and other ncRNAs), and lipid mediators and can shuttle their exosomal content to both neighboring and distal cells. Exosomes are very effective in orchestrating immune responses in the airways and all cell types can contribute to the systemic exosome pool. Intracellular communication between the broad range of cell types within the lung is crucial in disease emphasizing the importance of exosomes. In asthma, exosomes affect the inflammatory microenvironment which ultimately determines the development or alleviation of the pathological symptoms. Recent studies in this area have provided insight into the underlying mechanisms of disease and led to interest in using exosomes as potential novel therapeutic agents.

Effect of methamphetamine exposure on the plasma levels of endothelial-derived microparticles

BACKGROUND

Methamphetamine (Meth), a neurotoxin, induces inflammation, oxidative stress, and triggers endothelial dysfunction and cardiovascular disease which is the second cause of death among individuals with Meth-use disorder. Oxidative stress and inflammation trigger the microparticle (MP) release. These are extracellular vesicles extracted from cell surface and identified in biological fluids. MP levels alter during pathological conditions, suggesting its potential biomarker role. In this respect, we designed the present experiment to investigate the effects of Meth on the plasma level of the endothelial-derived microparticle (EMP).

METHODS

Animals received Meth (4 mg/kg i.p.) for 1, 7 and 14 days and then, the plasma level of EMPs was evaluated, using cell surface markers, including AnnexinV, CD144, CD31, CD41a antigens with the flow cytometry method. The biochemical indices and locomotor activity were also assessed in a rat model.

RESULTS

Meth increased locomotor activity (Meth-1, 277.12 ± 20.17; Meth-7, 262.25 ± 11.95; Meth-14, 265.75 ± 14.75), inflammatory and oxidative indices as evidenced by rising of the C-reactive protein (Meth-7, 39.4 ± 1.24; Meth-14, 38.58 ± 2.19, vs 8.65 ± 0.45, mg/L) and malondialdehyde (Meth-7, 9.74 ± 1.38; Meth-14, 14.6 ± 1.45, vs 4.43 ± 0.32 nmol/L) plasma levels. We also found that Meth triggered endothelial injury, as demonstrated by elevated levels of EMP (Meth-7, 4.77 ± 0.22; Meth-14, 5.91 ± 0.34, % total events/mL) compared with control group.

CONCLUSION

Our data showed that Meth exposure stimulates inflammatory and oxidative pathways and facilitates the EMPs shedding. Measuring the level of EMPs might be applied as a potential diagnostic index to monitor the endothelial dysfunction in substance-use disorders.

Exosome-mediated peritoneal dissemination in gastric cancer and its clinical applications

The prognosis of patients with peritoneal dissemination from gastric cancer is poor, and the underlying molecular mechanism remains unclear. Exosomes, as macromolecular phospholipid bilayer vesicles comprising of proteins, nucleic acids and lipids, serve as mediators of cell-cell communication. Gastric cancer tumor-derived exosomes may be involved in the pathological process of peritoneal dissemination by mediating crosstalk between cancer cells and mesothelial cells, to result in the induction of enhanced tumor growth, migratory, adhesive and invasive abilities, peritoneal fibrosis and apoptosis, mesothelial-to-mesenchymal transition, angiogenesis and chemoresistance. The present review focuses on previous studies addressing the exosome-dependent molecular transfer in peritoneal dissemination in gastric cancer and the potential clinical applications.

The role of regulatory RNAs (miRNAs) in asthma

INTRODUCTION

Recently, a great deal of attention has been paid to the investigation of regulatory functions of microRNA. Currently, many different mechanisms involved in the pathogenesis of asthma are known, but the whole picture of pathogenesis has not yet been studied.

CONCLUSIONS

MicroRNAs play an important role in the regulation of many cellular processes. Undoubtedly, these regulatory molecules are involved in the pathogenesis of asthma, and therefore can be potential targets for treatment.

Biological Functions and Current Advances in Isolation and Detection Strategies for Exosome Nanovesicles

Exosomes are nanoscale (≈30-150 nm) extracellular vesicles of endocytic origin that are shed by most types of cells and circulate in bodily fluids. Exosomes carry a specific composition of proteins, lipids, RNA, and DNA and can work as cargo to transfer this information to recipient cells. Recent studies on exosomes have shown that they play an important role in various biological processes, such as intercellular signaling, coagulation, inflammation, and cellular homeostasis. These functional roles are attributed to their ability to transfer RNA, proteins, enzymes, and lipids, thereby affecting the physiological and pathological conditions in various diseases, including cancer and neurodegenerative, infectious, and autoimmune diseases (e.g., cancer initiation, progression, and metastasis). Due to these unique characteristics, exosomes are considered promising biomarkers for the diagnosis and prognosis of various diseases via noninvasive or minimally invasive procedures. Over the last decade, a plethora of methodologies have been developed for analyzing disease-specific exosomes using optical and nonoptical tools. Here, the major biological functions, significance, and potential role of exosomes as biomarkers and therapeutics are discussed. Furthermore, an overview of the most commonly used techniques for exosome analysis, highlighting the major technical challenges and limitations of existing techniques, is presented.

Extracellular Vesicle MicroRNA Transfer in Lung Diseases

MicroRNAs (miRNAs) are single-stranded, small non-coding RNAs that ate involved in the transcriptional and post-transcriptional regulation of gene expression. Recently, miRNAs were demonstrated to be effectively delivered to a target cell or tissue from a host cell via extracellular vesicles (EVs). These EVs can be detected in blood, urine, exhaled breath condensates, bronchoalveolar lavage fluid (BALF), and other fluids. miRNAs are generated by donor cells and then packaged into EVs and delivered with intact functionality. After being delivered to the target cells, they regulate the translation of their target genes and the function of the target cells. Thus, EV transported miRNAs have become a new method for intercellular communication. EV miRNA transfer is well-documented in various pulmonary diseases, such as chronic obstructive pulmonary disease (COPD), asthma, pulmonary hypertension, and acute lung injury (ALI). In this review, we summarize the novel findings of EV miRNA transfer, focusing on the roles of miR-210, miR-200, miR-17, miR-146a, miR-155, and other miRNAs that are transported from primary human bronchial epithelial cells (HBECs), BALF, mesenchymal stem cells, and dendritic cells.

Stem-cell extracellular vesicles and lung repair

Four out of the ten leading causes of morbidity and mortality worldwide are lung diseases. Despite advances in comprehending the pathophysiological mechanisms involved in these disorders, for several respiratory diseases, there is still no effective treatment able to stop their natural history or reverse the morphological and functional damage they cause. In this context, recent research has supported a potential role of cell therapy for lung diseases and critical illness. The anti-inflammatory, antifibrotic, and microbicidal effects of stem cells are mainly attributed to their secretome, which contains proteins, lipids, microRNAs, and mRNAs. These are secreted in the conditioned medium and are also present in extracellular vesicles (EVs). This review will provide a detailed discussion of the role of EVs produced by mesenchymal stromal cells in preclinical experimental models of pulmonary disorders and critical illness, as well as in ongoing clinical trials.

Effects of storage temperature on airway exosome integrity for diagnostic and functional analyses

Background: Extracellular vesicles contain biological molecules specified by cell-type of origin and modified by microenvironmental changes. To conduct reproducible studies on exosome content and function, storage conditions need to have minimal impact on airway exosome integrity. Aim: We compared surface properties and protein content of airway exosomes that had been freshly isolated vs. those that had been treated with cold storage or freezing. Methods: Mouse bronchoalveolar lavage fluid (BALF) exosomes purified by differential ultracentrifugation were analysed immediately or stored at +4°C or -80°C. Exosomal structure was assessed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and charge density (zeta potential, ζ). Exosomal protein content, including leaking/dissociating proteins, were identified by label-free LC-MS/MS. Results: Freshly isolated BALF exosomes exhibited a mean diameter of 95 nm and characteristic morphology. Storage had significant impact on BALF exosome size and content. Compared to fresh, exosomes stored at +4°C had a 10% increase in diameter, redistribution to polydisperse aggregates and reduced ζ. Storage at -80°C produced an even greater effect, resulting in a 25% increase in diameter, significantly reducing the ζ, resulting in multilamellar structure formation. In fresh exosomes, we identified 1140 high-confidence proteins enriched in 19 genome ontology biological processes. After storage at room temperature, 848 proteins were identified. In preparations stored at +4°C, 224 proteins appeared in the supernatant fraction compared to the wash fractions from freshly prepared exosomes; these proteins represent exosome leakage or dissociation of loosely bound "peri-exosomal" proteins. In preparations stored at -80°C, 194 proteins appeared in the supernatant fraction, suggesting that distinct protein groups leak from exosomes at different storage temperatures. Conclusions: Storage destabilizes the surface characteristics, morphological features and protein content of BALF exosomes. For preservation of the exosome protein content and representative functional analysis, airway exosomes should be analysed immediately after isolation.

Novel Modulators of Asthma and Allergy: Exosomes and MicroRNAs

Intercellular communication is crucial to the immune system response. In the recent years, the discovery of exosomes has changed the way immune response orchestration was understood. Exosomes are able to operate as independent units that act as mediators in both physiological and pathological conditions. These structures contain proteins, lipidic mediators, and nucleic acids and notoriously include microRNAs (miRNAs). miRNAs are short RNA sequences (around 19-22 nucleotides) with a high phylogenetic conservation and can partially or totally regulate multiple mRNAs, inhibiting protein synthesis. In respiratory diseases such as asthma and allergic sensitization, exosomes released by several cell types and their specific content perform crucial functions in the development and continuation of the pathogenic mechanisms. Released exosomes and miRNAs inside them have been found in different types of clinical samples, such as bronchoalveolar lavage fluids and sputum supernatants, providing new data about the environmental factors and mediators that participate in the inflammatory responses that lead to the exacerbation of asthma. In this review, we summarize our current knowledge of the role of exosomes and miRNAs in asthma and allergic sensitization, paying attention to the functions that both exosomes and miRNAs are described to perform through the literature. We review the effect of exosomes and miRNAs in cells implicated in asthma pathology and the genes and pathways that they modify in them, depicting how their behavior is altered in disease status. We also describe their possible repercussion in asthma diagnosis through their possible role as biomarkers. Therefore, both exosomes and miRNAs can be viewed as potential tools to be added to the arsenal of therapeutics to treat this disease.

Neuroendocrinology of mast cells: Challenges and controversies

Mast cells (MC) are hemotopoietically derived tissue immune cells that are ubiquitous in the body, including neuroendocrine organs such as the hypothalamus, pineal, pituitary, ovaries, pancreas and uterus where their action is not well understood. Mast cells have historically been associated with allergies because of their rich content of histamine and tryptase, but more recently with regulation of immunity and inflammation due to their synthesis and release of numerous cytokines and chemokines. Mast cells are located perivascularly and express numerous receptors for diverse ligands such as allergens, pathogens, neurotransmitters, neuropeptides and hormones including acetylcholine, calcitonin gene-related peptide (CGRP), corticosteroids, corticotropin-releasing hormone (CRH), β-endorphin, epinephrine, 17β-oestradiol, gonadotrophins, hemokinin-A (HKA), leptin, melatonin, neurotensin (NT), parathyroid hormone (PTH), substance P (SP) and vasoactive intestinal peptide (VIP). Moreover, MC can synthesize and release most of their neurohormonal triggers, including adrenocorticotropin hormone (ACTH), CRH, endorphins, HKA, leptin, melatonin, NT, SP and VIP. Animal experiments have shown that diencephalic MC increase in number during courting in doves, while stimulation of brain and nasal MC leads to activation of the hypothalamic-pituitary-adrenal (HPA) axis. Recent evidence indicates that MC reactivity exhibits diurnal variations, and it is interesting that melatonin appears to regulate MC secretion. However, the way MC change their phenotype or secrete specific molecules selectively at different pathophysiological settings still remains unknown. Mast cells developed over 500 million years ago and may have served as the original prototype neuroimmunoendocrine cell and then evolved into a master regulator of such interactions, especially as most of the known diseases involve neuroinflammation that worsens with stress.

Amoxicillin haptenates intracellular proteins that can be transported in exosomes to target cells

BACKGROUND

Allergic reactions to β-lactams are among the most frequent causes of drug allergy and constitute an important clinical problem. Drug covalent binding to endogenous proteins (haptenation) is thought to be required for activation of the immune system. Nevertheless, neither the nature nor the role of the drug protein targets involved in this process is fully understood. Here, we aim to identify novel intracellular targets for haptenation by amoxicillin (AX) and their cellular fate.

METHODS

We have treated B lymphocytes with either AX or a biotinylated analog (AX-B). The identification of protein targets for haptenation by AX has been approached by mass spectrometry and immunoaffinity techniques. In addition, intercellular communication mediated by the delivery of vesicles loaded with AX-B-protein adducts has been explored by microscopy techniques.

RESULTS

We have observed a complex pattern of AX-haptenated proteins. Several novel targets for haptenation by AX in B lymphocytes have been identified. AX-haptenated proteins were detected in cell lysates and extracellularly, either as soluble proteins or in lymphocyte-derived extracellular vesicles. Interestingly, exosomes from AX-B-treated cells showed a positive biotin signal in electron microscopy. Moreover, they were internalized by endothelial cells, thus supporting their involvement in intercellular transfer of haptenated proteins.

CONCLUSIONS

These results represent the first identification of AX-mediated haptenation of intracellular proteins. Moreover, they show that exosomes can constitute a novel vehicle for haptenated proteins, and raise the hypothesis that they could provide antigens for activation of the immune system during the allergic response.