Exosomes from bronchoalveolar fluid of tolerized mice prevent allergic reaction

Exosomal Non-coding RNA Derived from Mesenchymal Stem Cells (MSCs) in Autoimmune Diseases Progression and Therapy; an Updated Review

Inflammation and autoimmune diseases (AD) are common outcomes of an overactive immune system. Inflammation occurs due to the immune system reacting to damaging stimuli. Exosomes are being recognized as an advanced therapeutic approach for addressing an overactive immune system, positioning them as a promising option for treating AD. Mesenchymal stem cells (MSCs) release exosomes that have strong immunomodulatory effects, influenced by their cell of origin. MSCs-exosomes, being a cell-free therapy, exhibit less toxicity and provoke a diminished immune response compared to cell-based therapies. Exosomal non-coding RNAs (ncRNA), particularly microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are intricately linked to various biological and functional aspects of human health. Exosomal ncRNAs can lead to tissue malfunction, aging, and illnesses when they experience tissue-specific alterations as a result of various internal or external problems. In this study, we will examine current trends in exosomal ncRNA researches regarding AD. Then, therapeutic uses of MSCs-exosomal ncRNA will be outlined, with a particle focus on the underlying molecular mechanisms.

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.

The Role of Extracellular Vesicles in Allergic Sensitization: A Systematic Review

Allergies affect approximately 10-30% of people worldwide, with an increasing number of cases each year; however, the underlying mechanisms are still poorly understood. In recent years, extracellular vesicles (EVs) have been suggested to play a role in allergic sensitization and skew to a T helper type 2 (Th2) response. The aim of this review is to highlight the existing evidence of EV involvement in allergies. A total of 22 studies were reviewed; 12 studies showed EVs can influence a Th2 response, while 10 studies found EVs promoted a Th1 or Treg response. EVs can drive allergic sensitization through up-regulation of pro-Th2 cytokines, such as IL-4 and IL-13. In addition, EVs from MRSA can induce IgE hypersensitivity in mice towards MRSA. On the other hand, EVs can induce tolerance in the immune system; for example, pre-exposing OVA-loaded EVs prevented OVA sensitization in mice. The current literature thus suggests that EVs play an essential role in allergy. Further research utilizing human in vitro models and clinical studies is needed to give a reliable account of the role of EVs in allergy.

Therapeutic potential of mesenchymal stem cell-derived exosomes for allergic airway inflammation

Due to their immunomodulatory capacities, mesenchymal stem cells (MSCs) have been extensively used as therapeutic approaches in cell-based therapy for various inflammatory diseases. Several lines of studies have shown that the most beneficial effects of MSCs are associated with MSC-derived exosomes. Exosomes are nanoscale extracellular vesicles that contain important biomolecules such as RNA, microRNAs (miRNAs), DNA, growth factors, enzymes, chemokines, and cytokines that regulate immune cell functions and parenchymal cell survival. Recently, exosomes, especially MSC-derived exosomes, have been shown to have protective effects in allergic airway inflammation. This review focused on the immune-regulatory potential of MSC-derived exosomes as nanoscale delivery systems in the treatment of allergic airway inflammation.

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

Diagnostic and therapeutic value of EVs in lungs diseases and inflammation

Extracellular vesicles (EVs) are membrane-derived messengers which have been playing an important role in the inflammation and pathogenesis of lung diseases. EVs contain varieties of DNA, RNA, and membrane receptors through which they work as a delivery system for bioactive molecules as well as intracellular communicators. EV signaling mediates tumor progression and metastasis. EVs are linked with many diseases and perform a diagnostic role in lung injury and inflammation so are used to diagnose the severity of diseases. EVs containing a variety of biomolecules communicate with the recipient cells during pathophysiological mechanisms thereby acquiring the attention of clinicians toward the diagnostic and therapeutic potential of EVs in different lung diseases. In this review, we summarize the role of EVs in inflammation with an emphasis on their potential as a novel candidate in the diagnostics and therapeutics of chronic obstructive pulmonary disease, asthma, and sarcoidosis.

Research trends and hotspots of exosomes in respiratory diseases

Currently, theoretical studies on exosomes in respiratory diseases have received much attention from many scholars and have made remarkable progress, which has inestimable value and potential in future clinical and scientific research. Unfortunately, no scholar has yet addressed this field's bibliometric analysis and summary. We aim to comprehensively and profoundly study and explore the present situation and highlights of exosome research at the stage of respiratory diseases and to provide meaningful insights for the future development of this field. The WOSCC literature was gathered for the study using bibliometrics, and the data were collected and analyzed using CiteSpace, VOSviewer, Microsoft Excel, and Endnote software. The publication language is "English," and the search strategy is TS = (exosome OR exosomes OR exosomal) AND TS = (respiratory OR lung). The search time is from the beginning of the WOS construction, and the deadline is July 11, 2022, at 22:00 hours. The literature types selected were dissertation, review paper, and online published paper. The analysis includes 2456 publications in 738 journals from 76 countries, 2716 institutions, and 14,568 authors. The field's annual publications have been rising, especially in recent years. China and the US lead research, and prominent universities, including Harvard Medical School, Shanghai Jiao Tong University, and Fudan University, are essential research institutes. Takahiro Ochiya, whose research focuses on exosomes and lung cancer, and Clotilde Théry, a pioneering exosome researcher, are the most cited authors in this field. The key terms include lung cancer, non-small cell lung cancer, mesenchymal stem cells, intercellular communication, exosomal miRNAs, and oncology. Cell biology, biochemistry & biotechnology, and oncology are related fields. The final summary of research hotspots is exosomes and lung cancer, mesenchymal stem cell-derived exosomes and lung inflammation, and miRNAs in exosomes as biomarkers for respiratory illnesses. The present research situation and relevant hotspots of the area were analyzed through bibliometric studies on exosomes in respiratory diseases. The research development in this field has a considerable upside, and the exosome's function in diagnosing, treating, monitoring, and prognosis of respiratory illnesses cannot be taken lightly. Moreover, we believe the research results will bring the gospel to many patients with clinical respiratory diseases shortly.

Extracellular vesicles as next generation immunotherapeutics

Extracellular vesicles (EVs) function as a mode of intercellular communication and molecular transfer to elicit diverse biological/functional response. Accumulating evidence has highlighted that EVs from immune, tumour, stromal cells and even bacteria and parasites mediate the communication of various immune cell types to dynamically regulate host immune response. EVs have an innate capacity to evade recognition, transport and transfer functional components to target cells, with subsequent removal by the immune system, where the immunological activities of EVs impact immunoregulation including modulation of antigen presentation and cross-dressing, immune activation, immune suppression, and immune surveillance, impacting the tumour immune microenvironment. In this review, we outline the recent progress of EVs in immunorecognition and therapeutic intervention in cancer, including vaccine and targeted drug delivery and summarise their utility towards clinical translation. We highlight the strategies where EVs (natural and engineered) are being employed as a therapeutic approach for immunogenicity, tumoricidal function, and vaccine development, termed immuno-EVs. With seminal studies providing significant progress in the sequential development of engineered EVs as therapeutic anti-tumour platforms, we now require direct assessment to tune and improve the efficacy of resulting immune responses - essential in their translation into the clinic. We believe such a review could strengthen our understanding of the progress in EV immunobiology and facilitate advances in engineering EVs for the development of novel EV-based immunotherapeutics as a platform for cancer treatment.

Stem cell- derived extracellular vesicles as new tools in regenerative medicine - Immunomodulatory role and future perspectives

In the last few decades, the practical use of stem cells (SCs) in the clinic has attracted significant attention in the regenerative medicine due to the ability of these cells to proliferate and differentiate into other cell types. However, recent findings have demonstrated that the therapeutic capacity of SCs may also be mediated by their ability to secrete biologically active factors, including extracellular vesicles (EVs). Such submicron circular membrane-enveloped vesicles may be released from the cell surface and harbour bioactive cargo in the form of proteins, lipids, mRNA, miRNA, and other regulatory factors. Notably, growing evidence has indicated that EVs may transfer their bioactive content into recipient cells and greatly modulate their functional fate. Thus, they have been recently envisioned as a new class of paracrine factors in cell-to-cell communication. Importantly, EVs may modulate the activity of immune system, playing an important role in the regulation of inflammation, exhibiting broad spectrum of the immunomodulatory activity that promotes the transition from pro-inflammatory to pro-regenerative environment in the site of tissue injury. Consequently, growing interest is placed on attempts to utilize EVs in clinical applications of inflammatory-related dysfunctions as potential next-generation therapeutic factors, alternative to cell-based approaches. In this review we will discuss the current knowledge on the biological properties of SC-derived EVs, with special focus on their role in the regulation of inflammatory response. We will also address recent findings on the immunomodulatory and pro-regenerative activity of EVs in several disease models, including in vitro and in vivo preclinical, as well as clinical studies. Finally, we will highlight the current perspectives and future challenges of emerging EV-based therapeutic strategies of inflammation-related diseases treatment.

The emerging role of exosomes in innate immunity, diagnosis and therapy

Exosomes, which are nano-sized transport bio-vehicles, play a pivotal role in maintaining homeostasis by exchanging genetic or metabolic information between different cells. Exosomes can also play a vital role in transferring virulent factors between the host and parasite, thereby regulating host gene expression and the immune interphase. The association of inflammation with disease development and the potential of exosomes to enhance or mitigate inflammatory pathways support the notion that exosomes have the potential to alter the course of a disease. Clinical trials exploring the role of exosomes in cancer, osteoporosis, and renal, neurological, and pulmonary disorders are currently underway. Notably, the information available on the signatory efficacy of exosomes in immune-related disorders remains elusive and sporadic. In this review, we discuss immune cell-derived exosomes and their application in immunotherapy, including those against autoimmune connective tissue diseases. Further, we have elucidated our views on the major issues in immune-related pathophysiological processes. Therefore, the information presented in this review highlights the role of exosomes as promising strategies and clinical tools for immune regulation.

Exosomes Released by Influenza-Virus-Infected Cells Carry Factors Capable of Suppressing Immune Defense Genes in Naïve Cells

Background: Exosomes are involved in intercellular communication and can transfer regulatory molecules between cells. Consequently, they can participate in host immune response regulation. For the influenza A virus (IAV), there is very limited information on changes in exosome composition during cell infection shedding light on the potential role of these extracellular membrane vesicles. Thus, the aim of our work was to study changes in exosomal composition following IAV infection of cells, as well as to evaluate their effect on uninfected cells. Methods: To characterize changes in the composition of cellular miRNAs and mRNAs of exosomes during IAV infection of A549 cells, NGS was used, as well as PCR to identify viral genes. Naïve A549 cells were stimulated with infected-cell-secreted exosomes for studying their activity. Changes in the expression of genes associated with the cell's immune response were shown using PCR. The effect of exosomes on IAV replication was shown in MDCK cells using In-Cell ELISA and PCR of the supernatants. Results: A change in the miRNA composition (miR-21-3p, miR-26a-5p, miR-23a-5p, miR-548c-5p) and mRNA composition (RPL13A, MKNK2, TRIB3) of exosomes under the influence of the IAV was shown. Many RNAs were involved in the regulation of the immune response of the cell, mainly by suppressing it. After exosome stimulation of naïve cells, a significant decrease in the expression of genes involved in the immune response was shown (RIG1, IFIT1, MDA5, COX2, NFκB, AnxA1, PKR, IL6, IL18). When infecting MDCK cells, a significant decrease in nucleoprotein levels was observed in the presence of exosomes secreted by mock-infected cells. Viral levels in supernatants also decreased. Conclusions: Exosomes secreted by IAV-infected cells could reduce the immune response of neighboring intact cells, leading to more effective IAV replication. This may be associated both with regulatory functions of cellular miRNAs and mRNAs carried by exosomes, or with the presence of viral mRNAs encoding proteins with an immunosuppressive function.

Extracellular vesicles and their miRNA contents counterbalance the pro-inflammatory effect of air pollution during physiological pregnancy: A focus on Syncytin-1 positive vesicles

The impact of exposure to respirable particulate matter (PM) during pregnancy is a growing concern, as several studies have associated increased risks of adverse pregnancy and birth outcomes, and impaired intrauterine growth with air pollution. The molecular mechanisms responsible for such effects are still under debate. Extracellular vesicles (EVs), which travel in body fluids and transfer microRNAs (miRNAs) between tissues (e.g., pulmonary environment and placenta), might play an important role in PM-induced risk. We sought to determine whether the levels of PM with aerodynamic diameters of ≤10 µm (PM₁₀) and ≤2.5 µm (PM_2.5) are associated with changes in plasmatic EV release and EV-miRNA content by investigating 518 women enrolled in the INSIDE study during the first trimester of pregnancy. In all models, we included both the 90-day averages of PM (long-term effects) and the differences between the daily estimate of PM and the 90-day average (short-term effects). Short-term PM₁₀ and PM_2.5 were associated with increased concentrations of all seven EV types that we assayed (positive for human antigen leukocyte G (HLA-G), Syncytin-1 (Sync-1), CD14, CD105, CD62e, CD61, or CD25 determinants), while long-term PM₁₀ showed a trend towards decreased EV concentrations. Increased Sync-1 + EV levels were associated with the plasmatic decrease of sVCAM-1, but not of sICAM-1, which are circulating biomarkers of endothelial dysfunction. Thirteen EV-miRNAs were downregulated in response to long-term PM₁₀ and PM_2.5 variations, while seven were upregulated (p-value < 0.05, false discovery rate p-value (qFDR) < 0.1). Only one EV-miRNA (hsa-miR-221-3p) was downregulated after short-term variations. The identified PM-modulated EV-miRNAs exhibited putative roles in inflammation, gestational hypertension, and pre-eclampsia, as highlighted by miRNA target analysis. Our findings strongly support the hypothesis that EVs have an important role in modulating PM exposure effects during pregnancy, possibly through their miRNA cargo.

Safety and biodistribution of exosomes derived from human induced pluripotent stem cells

As a new cell-free therapy, exosomes have provided new ideas for the treatment of various diseases. Human induced pluripotent stem cells (hiPSCs) cannot be used in clinical trials because of tumorigenicity, but the exosomes derived from hiPSCs may combine the advantages of iPSC pluripotency and the nanoscale size of exosomes while avoiding tumorigenicity. Currently, the safety and biodistribution of hiPSC-exosomes in vivo are unclear. Here, we investigated the effects of hiPSC-exosomes on hemolysis, DNA damage, and cytotoxicity through cell experiments. We also explored the safety of vein injection of hiPSC-exosomes in rabbits and rats. Differences in organ distribution after nasal administration were compared in normal and Parkinson’s disease model mice. This study may provide support for clinical therapy and research of intravenous and nasal administration of hiPSC-exosomes.

The Potential of Exosomes in Allergy Immunotherapy

Allergic diseases represent a global health and economic burden of increasing significance. The lack of disease-modifying therapies besides specific allergen immunotherapy (AIT) which is not available for all types of allergies, necessitates the study of novel therapeutic approaches. Exosomes are small endosome-derived vesicles delivering cargo between cells and thus allowing inter-cellular communication. Since immune cells make use of exosomes to boost, deviate, or suppress immune responses, exosomes are intriguing candidates for immunotherapy. Here, we review the role of exosomes in allergic sensitization and inflammation, and we discuss the mechanisms by which exosomes could potentially be used in immunotherapeutic approaches for the treatment of allergic diseases. We propose the following approaches: (a) Mast cell-derived exosomes expressing IgE receptor FcεRI could absorb IgE and down-regulate systemic IgE levels. (b) Tolerogenic exosomes could suppress allergic immune responses via induction of regulatory T cells. (c) Exosomes could promote TH1-like responses towards an allergen. (d) Exosomes could modulate IgE-facilitated antigen presentation.

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.

Plasma EVs Display Antigen-Presenting Characteristics in Patients With Allergic Rhinitis and Promote Differentiation of Th2 Cells

Background

Allergic rhinitis (AR) is characterized by IgE-mediated mucosa response after exposure to allergens. Extracellular vesicles (EVs) are nano-size vesicles containing biological cargos for intercellular communications. However, the role of plasma EVs in pathogenesis of AR remains largely unknown.

Methods

Plasma EVs from patients with AR were isolated, quantified, and characterized. The expression of Der p 1 and antigen-presenting molecules on EVs was determined by Western blot, flow cytometry, or ELISA. PKH26- and CFSE (carboxyfluorescein succinimidyl ester)-stained AR-EVs were used to determine the uptake of EVs by CD4⁺T cells and their effects on CD4⁺T cell proliferation, respectively.

Results

Plasma EVs in healthy control (HC) and AR patients were similar in the concentration of particles, expression for specific EV markers, and both had structural lipid bilayer. However, the levels of Der p 1 on plasma EVs from both mild and moderate-severe AR patients were significantly higher than that on HC. The levels of antigen-presenting molecules on plasma EVs were similar from three subjects. Moreover, levels of Der p 1 on EVs in plasma, but not nasal secretion, were significantly associated with the symptom score of AR patients and level of plasma IL-13. Additionally, plasma EVs from patients with AR promoted the development of Th2 cells, while no effect was found on CD4⁺ T-cell proliferation.

Conclusions

Plasma EVs derived from patients with AR exhibited antigen-presenting characteristics and promoted differentiation of Th2 cells, thus providing novel understanding of the pathogenesis of AR.

Exosomes in chronic respiratory diseases

Exosomes are nano-sized vesicles released by almost all cell types, with a central role as mediators of intercellular communication. In addition to physiological conditions, these extracellular vesicles seem to play a pivotal role in inflammatory processes. This assumption offers the opportunity to study exosomes as promising biomarkers and therapeutic tools for chronic respiratory disorders. Indeed, although it is well-known that at the basis of conditions like asthma, chronic obstructive pulmonary disease, alpha-1 antitrypsin deficiency and idiopathic pulmonary fibrosis there is a dysregulated inflammatory process, an unequivocal correlation between different phenotypes and their pathophysiological mechanisms has not been established yet. In this review, we report and discuss some of the most significant studies on exosomes from body fluids of subjects affected by airway diseases. Furthermore, the most widespread techniques for exosome isolation and characterization are described. Further studies are needed to answer the unresolved questions about the functional link between exosomes and chronic respiratory diseases.

Vaccination with circulating exosomes in autoimmune uveitis prevents recurrent intraocular inflammation

BACKGROUND

Exosomes participate in intercellular communication and act as important molecular vehicles in the regulation of numerous physiological and pathological processes, including autoimmune development. The role of circulating exosomes in the development of autoimmune uveitis is unknown. In this study, using the rat model of experimental autoimmune uveitis, which has clinical and histological features of pan uveitis in man, we evaluated the immunoregulatory function of circulating exosomes.

METHODS

Experimental autoimmune uveitis was induced in Lewis rats either immunised with interphotoreceptor retinoid-binding protein R16 peptides or injected with activated R16-specific T cells. The disease incidence and severity were examined by indirect fundoscopy and flow cytometry. Circulating exosomes were isolated from peripheral blood of naïve and Day 14 R16 immunised Lewis rats. The effect of exosomes on specific T cells was evaluated by R16-specific T cell proliferation, cytokine production and recurrent uveitis induction.

RESULTS

Circulating exosomes derived from active immunised uveitis rats selectively inhibited immune responses of R16-specific T cells in vitro. Vaccination of naïve rats with these exosomes reduced the incidence of recurrent uveitis in an antigen-specific manner. Antigen-specific uveitogenic T cells reduced IFN-γ production and increased IL-10 after vaccination.

CONCLUSIONS

Circulating exosomes in autoimmune uveitis have the potential to be a novel treatment for recurrent autoimmune uveitis.

Mechanism of miR-204-5p in exosomes derived from bronchoalveolar lavage fluid on the progression of pulmonary fibrosis via AP1S2

Background

Exosomes are nanoscale vesicles secreted by various types of cells that are responsible for intracellular communication. Despite that bronchoalveolar lavage fluid (BALF) has been proven to involve in tumor development, more efforts are required to investigate the impact of BALF on pulmonary fibrosis (PF). This study aimed to investigate the mechanism of how exosomal miR-204-5p from BALF facilitates PF progression in rats.

Methods

PF rat model was established by intratracheal injection of bleomycin. BALF-derived exosomes (Exo) were extracted from normal and PF rats. PF-Exo (BALF-derived Exo from PF rats) and miR-204-5p antagomir were injected into rats to investigate the effect of exosomal miR-204-5p on PF. Collagen content in lung tissues of rats was assessed by Masson staining, hydroxyproline (HYP) content assay and immunohistochemistry (IHC). Primary lung fibroblasts were isolated, and treated by TGF-β1. After co-transfection of PF-Exo, miR-204-5p inhibitor and sh-AP1S2, cell proliferation, levels of miR-204-5p, fibrotic markers α-SMA and collagen 1 (Col 1), and proteins of autophagy markers LC3II, LC3I and P62 were measured. The interaction between miR-204-5p and AP1S2 was determined by bioinformatics online software TargetScan and dual-luciferase reporter assay.

Results

miR-204-5p was abundantly expressed in the PF-Exo group. PF-Exo injection potentiated PF progression and proliferation ability of lung fibroblasts in vivo and in vitro. Injection with PF-Exo and miR-204-5p antagomir significantly increased the LC3II/I ratio and decreased the HYP content, proteins of α-SMA, Col 1 and P62, collagen content in rat lung tissues of PF rats. TGF-β1 induction elevated the LC3II/LC3I ratio, suppressed the cell proliferation rate, and decreased the levels of α-SMA, Col 1 and P62. Additionally, AP1S2 was a direct target of miR-204-5p. miR-204-5p inhibitor can counteract the effect of PF-Exo in proliferation of lung fibroblasts, while sh-AP1S2 eliminated the effect of miR-204-5p inhibitor.

Conclusions

Exosomal miR-204-5p from BALF inhibits autophagy to promote the progression of PF rats by targeting AP1S2.

The Role of Non-Immune Cell-Derived Extracellular Vesicles in Allergy

Extracellular vesicles (EVs), and especially exosomes, have been shown to mediate information exchange between distant cells; this process directly affects the biological characteristics and functionality of the recipient cell. As such, EVs significantly contribute to the shaping of immune responses in both physiology and disease states. While vesicles secreted by immune cells are often implicated in the allergic process, growing evidence indicates that EVs from non-immune cells, produced in the stroma or epithelia of the organs directly affected by inflammation may also play a significant role. In this review, we provide an overview of the mechanisms of allergy to which those EVs contribute, with a particular focus on small EVs (sEVs). Finally, we also give a clinical perspective regarding the utilization of the EV-mediated communication route for the benefit of allergic patients.

Mesenchymal growth hormone receptor deficiency leads to failure of alveolar progenitor cell function and severe pulmonary fibrosis

Recent studies have identified impaired type 2 alveolar epithelial cell (ATII) renewal in idiopathic pulmonary fibrosis (IPF) human organoids and severe fibrosis when ATII is defective in mice. ATIIs function as progenitor cells and require supportive signals from the surrounding mesenchymal cells. The mechanisms by which mesenchymal cells promote ATII progenitor functions in lung fibrosis are incompletely understood. We identified growth hormone receptor (GHR) is mainly expressed in mesenchymal cells, and its expression is substantially decreased in IPF lungs. Higher levels of GHR expression correlated with better lung function in patients with IPF. Profibrotic mesenchymal cells retarded ATII growth and were associated with suppressed vesicular GHR expression. Vesicles enriched with Ghr promote ATII proliferation and diminished pulmonary fibrosis in mesenchymal Ghr-deficient mice. Our findings demonstrate a previously unidentified mesenchymal paracrine signaling coordinated by GHR that is capable of supporting ATII progenitor cell renewal and limiting the severity of lung fibrosis.

Recent updates on the role of extracellular vesicles in the pathogenesis of allergic asthma

Asthma is a chronic inflammatory disease of the airway diagnosed with different endotypes and phenotypes, characterized by airway obstruction in response to allergens, bacterial/viral infections, or pollutants. Several cell types such as the airway epithelial cells, mesenchymal stem cells and different immune cells including dendritic cells (DCs), T and B cells and mast cells play an essential role during the pathobiology of asthma. Extracellular vesicles (EVs) are membranous nanovesicles produced by every cell type that facilitates intercellular communications. EVs contain heterogeneous cargos that primarily depend on the composition or cell type of origin and they can alter the physiological state of the target cells. EVs encompass a wide variety of proteins including Tetraspanins, MHC classes I and II, co-stimulatory molecules, nucleic acids such as RNA, miRNA, piRNA, circRNA, and lipids like ceramides and sphingolipids. Recent literature indicates that EVs play a pivotal role in the pathophysiology of allergic asthma and may potentially be used as a novel biomarker to determine endotypes and phenotypes in severe asthmatics. Based on the prior reports, we speculate that regulation of EVs biogenesis and release might be under the control of circadian rhythms. Thus, circadian rhythms may influence the composition of the EVs, which alter the microenvironment that results in the induction of an immune-inflammatory response to various environmental insults or allergens such as air pollutants, ozone, diesel exhaust particles, pollens, outdoor molds, environmental tobacco smoke, etc. In this mini-review, we summarize the recent updates on the novel role of EVs in the pathogenesis of asthma, and highlight the link between circadian rhythms and EVs that may be important to identify molecular mechanisms to target during the pathogenesis of chronic inflammatory lung disease such as asthma.

Harnessing adipose‑derived stem cells to release specialized secretome for the treatment of hepatitis B

Mesenchymal stem cells (MSCs) have the function of repairing damaged tissue, which is known to be mediated by the secretome, the collection of secretory materials shed from MSCs. Adjusting the culture conditions of MSCs can lead to a significant difference in the composition of the secretome. It was hypothesized that pre‑sensitization of MSCs with specific disease‑causing agents could harness MSCs to release the therapeutic materials specialized for the disease. To validate this hypothesis, the present study aimed to generate a 'disease‑specific secretome' for hepatitis caused by hepatitis B virus using hepatitis BX antigen (HBx) as a disease‑causing material. Secretary materials (HBx‑IS) were collected following the stimulation of adipose‑derived stem cells (ASCs) with 100‑fold diluted culture media of AML12 hepatocytes that had been transfected with pcDNA‑HBx for 24 h. An animal model of hepatitis B was generated by injecting HBx into mice, and the mice were subsequently intravenously administered a control secretome (CS) or HBx‑IS. Compared with the CS injection, the HBx‑IS injection significantly reduced the serum levels of interleukin‑6 and tumor necrosis factor‑α (pro‑inflammatory cytokines). Western blot analysis and immunohistochemistry of the liver specimens revealed that the HBx‑IS injection led to a higher expression of liver regeneration‑related markers, including hepatocyte growth factor and proliferating cell nuclear antigen, a lower expression of pro‑apoptotic markers, such as cleaved caspase 3 and Bim in mouse livers, and a lower expression of pro‑inflammatory markers (F4/80 and CD68) compared to the CS injection. HBx‑IS exhibited higher liver regenerative, anti‑inflammatory and anti‑apoptotic properties, particularly in the mouse model of hepatitis B compared to CS. This suggests that the secretome obtained by stimulating ASCs with disease‑causing agents may have a more prominent therapeutic effect on the specific disease than the naïve secretome.

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

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

Personalized medicine and back-allogeneic exosomes for cancer immunotherapy

Extracellular vesicles, especially exosomes, have been explored for cancer immunotherapy. The initial studies made use of autologous B-cell or dendritic cell-derived exosomes, with the idea that MHC-peptide complexes on the exosomal surface would stimulate an MHC-restricted cancer-specific immune response. This was also verified in mouse systems, whilst the effects in human clinical systems were more modest. Several studies have explored the mechanisms for exosomal T-cell activation, and a picture emerges where the antigen-presenting cells, possibly both B cells and dendritic cells of the recipient, are needed to induce a potent T-cell response to exosomes. Therefore, the exosomes function more as an adjuvant-like delivery system of antigens, and we need to further understand the exact components that trigger the most broad and potent immune responses. Here, we describe the grounds for using allogeneic exosomes for cancer therapy, something that would greatly improve the feasibility of new exosome-based immunotherapeutic approaches to cure cancer.

Exosomes: A Key Piece in Asthmatic Inflammation

Asthma is a chronic disease of the airways that has an important inflammatory component. Multiple cells are implicated in asthma pathogenesis (lymphocytes, eosinophils, mast cells, basophils, neutrophils), releasing a wide variety of cytokines. These cells can exert their inflammatory functions throughout extracellular vesicles (EVs), which are small vesicles released by donor cells into the extracellular microenvironment that can be taken up by recipient cells. Depending on their size, EVs can be classified as microvesicles, exosomes, or apoptotic bodies. EVs are heterogeneous spherical structures secreted by almost all cell types. One of their main functions is to act as transporters of a wide range of molecules, such as proteins, lipids, and microRNAs (miRNAs), which are single-stranded RNAs of approximately 22 nucleotides in length. Therefore, exosomes could influence several physiological and pathological processes, including those involved in asthma. They can be detected in multiple cell types and biofluids, providing a wealth of information about the processes that take account in a pathological scenario. This review thus summarizes the most recent insights concerning the role of exosomes from different sources (several cell populations and biofluids) in one of the most prevalent respiratory diseases, asthma.

Extracellular Vesicles in Viral Pathogenesis: A Case of Dr. Jekyll and Mr. Hyde

Secretion of extracellular vesicles (EVs) is a fundamental property of living cells. EVs are known to transfer biological signals between cells and thus regulate the functional state of recipient cells. Such vesicles mediate the intercellular transport of many biologically active molecules (proteins, nucleic acids, specific lipids) and participate in regulation of key physiological processes. In addition, EVs are involved in the pathogenesis of multiple diseases: infectious, neurodegenerative, and oncological. The current EV classification into microvesicles, apoptotic bodies, and exosomes is based on their size, pathways of cellular biogenesis, and molecular composition. This review is focused on analysis of the role of EVs (mainly exosomes) in the pathogenesis of viral infection. We briefly characterize the biogenesis and molecular composition of various EV types. Then, we consider EV-mediated pro- and anti-viral mechanisms. EV secretion by infected cells can be an important factor of virus spread in target cell populations, or a protective factor limiting viral invasion. The data discussed in this review, on the effect of EV secretion by infected cells on processes in neighboring cells and on immune cells, are of high significance in the search for new therapeutic approaches and for design of new generations of vaccines.

The Role of Heat Shock Protein 70 kDa in Asthma

Asthma is a complex chronic disorder of the airways, affecting immune and structural cells and inducing both protein and tissue remodeling. Heat shock proteins 70 kDa (HSP70s) are highly conserved members of the stress-induced family, possessing precisely described chaperone activity. There is growing evidence of a tight relationship between inflammatory diseases of different origins and the elevation of local HSP70 expression and secretion. Although extracellular HSP70 does not serve as a common marker of asthma, elevated HSP70 levels have been detected in the peripheral blood serum and sputum of patients with asthma, as well as in the bronchoalveolar lavage fluid of mice with induced allergic airway inflammation. Possessing diverse immunomodulating properties, extracellular HSP70 can manifest different activities in airway inflammatory processes and asthma, acting either as a pro-inflammatory trigger, or an anti-inflammatory agent. This review will discuss the effects and possible mechanisms concerning HSP70 implication in airway inflammation regulation in asthma. We examine ATPase and chaperone activities of HSP70 as potential modulators of immune responses in asthma. Given the crucial role of a chronic inflammatory response in asthma, understanding the effects of HSP70 on immune and structural cells may reveal new perspectives for the therapeutic control of inflammation.

Role of exosome in autoimmunity, with a particular emphasis on rheumatoid arthritis

Cell-derived exosomes are identified as carriers of lipids, proteins, and genetic materials that participate in cell-cell signal communication, biological process, and cell signaling. Also, their involvement has been reported in a vast array of disorders and inflammatory conditions such as autoimmune diseases. Rheumatoid arthritis (RA), a common cause of joint disorder, is an inflammation-based disease in which the precise understanding of its pathogenesis needs to be further investigated. Also, there is only a palliative care approach for the alleviation of RA symptoms. This paper discusses the recent advances in the biology of exosomes in autoimmune disorders especially in RA, and also provides a new line of research for arthritis therapy using exosomes.

Recent Advances in Extracellular Vesicles as Drug Delivery Systems and Their Potential in Precision Medicine

Extracellular vesicles (EVs) are membrane-bilayered nanoparticles released by most cell types. Recently, an enormous number of studies have been published on the potential of EVs as carriers of therapeutic agents. In contrast to systems such as liposomes, EVs exhibit less immunogenicity and higher engineering potential. Here, we review the most relevant publications addressing the potential and use of EVs as a drug delivery system (DDS). The information is divided based on the key steps for designing an EV-mediated delivery strategy. We discuss possible sources and isolation methods of EVs. We address the administration routes that have been tested in vivo and the tissue distribution observed. We describe the current knowledge on EV clearance, a significant challenge towards enhancing bioavailability. Also, EV-engineering approaches are described as alternatives to improve tissue and cell-specificity. Finally, a summary of the ongoing clinical trials is performed. Although the application of EVs in the clinical practice is still at an early stage, a high number of studies in animals support their potential as DDS. Thus, better treatment options could be designed to precisely increase target specificity and therapeutic efficacy while reducing off-target effects and toxicity according to the individual requirements of each patient.

Exosomes: A new horizon in modern medicine

Exosomes are a type of extracellular vesicles belonging to endocytic origin. These vesicles carry different biological cargo that play numerous physiological roles and is also indicative of different diseased state. Exosomes are considered as promising tools for therapeutic drug delivery, owing to their intrinsic features like stability, biocompatibility and a capacity of stealth. A clearer understanding of the composition, biogenesis and biology of exosomes can provide us with better insights into the pathophysiological, diagnostic, and therapeutic roles of these extracellular vesicles. In this review we have summarize existing literature regarding the production, efficacy, action mechanism, and potential therapeutic roles of exosomes in the contexts of various diseases such as cancer, renal disease, neurological disorders, cardio-vascular diseases, inflammatory diseases and some of the auto-immune diseases.

Cross-Talk Between Alveolar Macrophages and Lung Epithelial Cells is Essential to Maintain Lung Homeostasis

The main function of the lung is to perform gas exchange while maintaining lung homeostasis despite environmental pathogenic and non-pathogenic elements contained in inhaled air. Resident cells must keep lung homeostasis and eliminate pathogens by inducing protective immune response and silently remove innocuous particles. Which lung cell type is crucial for this function is still subject to debate, with reports favoring either alveolar macrophages (AMs) or lung epithelial cells (ECs) including airway and alveolar ECs. AMs are the main immune cells in the lung in steady-state and their function is mainly to dampen inflammatory responses. In addition, they phagocytose inhaled particles and apoptotic cells and can initiate and resolve inflammatory responses to pathogens. Although AMs release a plethora of mediators that modulate immune responses, ECs also play an essential role as they are more than just a physical barrier. They produce anti-microbial peptides and can secrete a variety of mediators that can modulate immune responses and AM functions. Furthermore, ECs can maintain AMs in a quiescent state by expressing anti-inflammatory membrane proteins such as CD200. Thus, AMs and ECs are both very important to maintain lung homeostasis and have to coordinate their action to protect the organism against infection. Thus, AMs and lung ECs communicate with each other using different mechanisms including mediators, membrane glycoproteins and their receptors, gap junction channels, and extracellular vesicles. This review will revisit characteristics and functions of AMs and lung ECs as well as different communication mechanisms these cells utilize to maintain lung immune balance and response to pathogens. A better understanding of the cross-talk between AMs and lung ECs may help develop new therapeutic strategies for lung pathogenesis.

Extracellular Vesicles: Recent Developments in Aging and Reproductive Diseases

Extracellular vesicles (EVs), present in cell culture media and several body fluids, play a prominent role in intercellular communication under physiological and pathological conditions. We performed a systematic literature search to review evidence regarding the existence, composition, and release of different EVs, as well as the biomarkers, cargos, and separation methods. We also reviewed the potential of EVs to transport cargos and alter the function and phenotype of recipient cells associated with aging and reproductive diseases, including polycystic ovary syndrome and endometriosis. In aging, EVs promote inflammatory reactions and offsetting the occurrence of aging. In the polycystic ovary syndrome and endometriosis, EVs and their cargos are involved in the occurrence of diseases, therapeutic strategies, and perform as non-invasive biomarkers. As the study of EVs is still in the early stages, it is not surprising that most of the current literature only describes their possible roles.

Modulating Cytokine Production via Select Packaging and Secretion From Extracellular Vesicles

Cytokines are soluble factors that play vital roles in systemic function due to their ability to initiate and mediate cell-to-cell communication. Another important mechanism of intercellular communication that has gained significant attention in the past 10 years is the release of extracellular vesicles (EVs). EVs are released by all cells during normal physiology, in states of resting and activation, as well as during disease. Accumulating evidence indicates that cytokines may be packaged into EVs, and the packaging of cytokines into EVs, along with their ultimate secretion, may also be regulated by cytokines. Importantly, the repertoire of biomolecules packaged into EVs is shaped by the biological state of the cell (resting vs. activated and healthy vs. disease) and the EV biogenesis pathway involved, thus providing mechanisms by which EV packaging and secretion may be modulated. Given the critical role of cytokines in driving acute and chronic inflammatory and autoimmune diseases, as well as their role in establishing the tumor immune microenvironment, in this review, we will focus on these disease settings and summarize recent progress and mechanisms by which cytokines may be packaged within and modulated by EVs, as a therapeutic option for regulating innate and adaptive immunity.

Oral Administration of Bovine and Porcine Milk Exosome Alter miRNAs Profiles in Piglet Serum

Breast milk is the most important nutrient source for newborn mammals. Studies have reported that milk contains microRNAs (miRNAs), which are potential regulatory components. Currently, existing functional and nutritional two competing hypotheses in milk field though little date have been provided for nutritional hypothesis. In this study, we used the qRT-PCR method to evaluated whether milk miRNAs can be absorbed by newborn piglets by feeding them porcine or bovine milk. The result showed that miRNA levels (miR-2284×, 2291, 7134, 1343, 500, 223) were significantly different between bovine and porcine milk. Four miRNAs (miR-2284×, 2291, 7134, 1343) were significantly different in piglet serum after feeding porcine or bovine milk. After separated milk exosomes by ultracentrifugation, the results showed the selected milk miRNAs (miR-2284×, 2291, 7134, 1343) were present in both exosomes and supernatants, and the miRNAs showed the coincidental expression in IPEC-J2 cells. All our founding suggested that the milk miRNAs can be absorbed both in vivo and in vitro, which will building the foundation for understanding whether these sort of miRNAs exert physiological functions after being absorbed and provided additional evidence for the nutritional hypotheses.

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.

Extracellular vesicles and asthma: A review of the literature

Asthma is a chronic, recurrent and incurable allergy-related respiratory disease characterized by inflammation, bronchial hyperresponsiveness and narrowing of the airways. Extracellular vesicles (EVs) are a universal feature of cellular function and can be detected in different bodily fluids. Recent evidence has shown the possibility of using EVs in understanding the pathogenesis of asthma, including their potential as diagnostic and therapeutic tools. Studies have reported that EVs released from key cells involved in asthma can induce priming and activation of other asthma-associated cells. A literature review was conducted on all current research regarding the role and function of EVs in the pathogenesis of asthma via the PRISMA statement method. An electronic search was performed using EMBASE and PubMed through to November 2018. The EMBASE search returned 76 papers, while the PubMed search returned 211 papers. Following duplicate removal, titles and abstracts were screened for eligibility with a total of 34 studies included in the final qualitative analysis. The review found evidence of association between the presence of EVs and physiological changes characteristic of asthma, suggesting that EVs are involved in the pathogenesis, with the weight of evidence presently favouring deleterious effects of EVs in asthma. Numerous studies highlighted differences in exosomal contents between EVs of healthy and asthmatic individuals, which could be employed as potential diagnostic markers. In some circumstances, EVs were also found to be suppressive to disease, but more often promote inflammation and airway remodelling. In conclusion, EVs hold immense potential in understanding the pathophysiology of asthma, and as diagnostic and therapeutic markers. While more research is needed for definitive conclusions and their application in medical practice, the literature presented in this review should encourage further research and discovery within the field of EVs and asthma.

Human airway epithelial extracellular vesicle miRNA signature is altered upon asthma development

BACKGROUND

miRNAs are master regulators of signaling pathways critically involved in asthma and are transferred between cells in extracellular vesicles (EV). We aimed to investigate whether the miRNA content of EV secreted by primary normal human bronchial epithelial cells (NHBE) is altered upon asthma development.

METHODS

NHBE cells were cultured at air-liquid interface and treated with interleukin (IL)-13 to induce an asthma-like phenotype. EV isolations by precipitation from basal culture medium or apical surface wash were characterized by nanoparticle tracking analysis, transmission electron microscopy, and Western blot, and EV-associated miRNAs were identified by a RT-qPCR-based profiling. Significant candidates were confirmed in EVs isolated by size-exclusion chromatography from nasal lavages of children with mild-to-moderate (n = 8) or severe asthma (n = 9), and healthy controls (n = 9).

RESULTS

NHBE cells secrete EVs to the apical and basal side. 47 miRNAs were expressed in EVs and 16 thereof were significantly altered in basal EV upon IL-13 treatment. Expression of miRNAs could be confirmed in EVs from human nasal lavages. Of note, levels of miR-92b, miR-210, and miR-34a significantly correlated with lung function parameters in children (FEV₁ FVC_%pred and FEF_25-75%pred ), thus lower sEV-miRNA levels in nasal lavages associated with airway obstruction. Subsequent ingenuity pathway analysis predicted the miRNAs to regulate Th2 polarization and dendritic cell maturation.

CONCLUSION

Our data indicate that secretion of miRNAs in EVs from the airway epithelium, in particular miR-34a, miR-92b, and miR-210, might be involved in the early development of a Th2 response in the airways and 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.

Molecular techniques for respiratory diseases: MicroRNA and extracellular vesicles

miRNA are a class of evolutionarily conserved non-coding 19- to 22-nt regulatory RNA. They affect various cellular functions through modulating the transcriptional and post-transcriptional levels of their target mRNA by changing the stability of protein-coding transcripts or attenuating protein translation. miRNA were discovered in the early 1990s, and they have been the focus of new research in both basic and clinical medical sciences. Today, it has become clear that specific miRNA are linked to the pathogenesis of respiratory diseases, as well as cancer and cardiovascular disease. In addition, EV, including exosomes, which are small membrane-bound vesicles secreted by cells, were found to contain various functional miRNA that can be used for diagnostic and therapeutic purposes. As body fluids, such as blood and respiratory secretions, are major miRNA sources in the body, EV carrying extracellular miRNA are considered potentially useful for the diagnosis and assessment of pathological conditions, as well as the treatment of respiratory or other diseases. Although research in the field of lung cancer is actively progressing, studies in other respiratory fields have emerged recently as well. In this review, we provide an update in the topics of miRNA and EV focused on airway inflammatory diseases, such as asthma and COPD, and explore their potential for clinical applications on respiratory diseases.

Isolation and characterization of extracellular vesicles from Broncho-alveolar lavage fluid: a review and comparison of different methods

Extracellular vesicles (EVs) are cell-derived membranous vesicles secreted by cells into the extracellular space, which play a role in cell to cell communication. EVs are categorized into 3 groups depending on their size, surface marker, and method of release from the host cell. Recently, EVs have become of interest in the study of multiple disease etiologies and are believed to be potential biomarkers for many diseases. Multiple different methods have been developed to isolate EVs from different samples such as cell culture medium, serum, blood, and urine. Once isolated, EVs can be characterized by technology such as nanotracking analysis, dynamic light scattering, and nanoscale flow cytometry. In this review, we summarize the current methods of EV isolation, provide details into the three methods of EV characterization, and provide insight into which isolation approaches are most suitable for EV isolation from bronchoalveolar lavage fluid (BALF).

Crucial Role of Extracellular Vesicles in Bronchial Asthma

Extracellular vesicles (EVs) are circulating vesicles secreted by various cell types. EVs are classified into three groups according to size, structural components, and generation process of vesicles: exosomes, microvesicles, and apoptotic bodies. Recently, EVs have been considered to be crucial for cell-to-cell communications and homeostasis because they contain intracellular proteins and nucleic acids. Epithelial cells from mice suffering from bronchial asthma (BA) secrete more EVs and suppress inflammation-induced EV production. Moreover, microarray analyses of bronchoalveolar lavage fluid have revealed that several microRNAs are useful novel biomarkers of BA. Mesenchymal stromal cell-derived EVs are possible candidates of novel BA therapy. In this review, we highlight the biologic roles of EVs in BA and review novel EV-targeted therapy to help understanding by clinicians and biologists.

Exosomes: A new approach to asthma pathology

Asthma is a chronic inflammatory disease of the airways with a complex pathophysiology, making the development of diagnostic and therapeutic tools a challenge. Exosomes are extracellular membranous nanovesicles implicated in intercellular communication. Exosome composition and cargo are highly heterogeneous depending on their cellular origin and physiological state. They contain proteins (tetraspanins, heat-shock proteins), nucleic acids (RNA, microRNA), and lipids (ceramides, cholesterol, sphingolipids). Current scientific advances show that exosomes play a pivotal role in the pathology of asthma as well as other inflammatory diseases, and all types of inflammatory cells (neutrophils, dendritic cells, lymphocytes, eosinophils) release exosomes. Also, structural lung cells such as airway epithelial cells and airway smooth muscle cells produce and secrete these nanovesicles. Exosomes influence and modify the functionality of these inflammatory and structural cells, triggering the characteristic processes of asthma disease. Additionally, exosomes are used as biomarkers in several disorders because they are easier to collect from different biofluids, making them a non-invasive method for screening human pathologies. Also, due to their special molecular characteristics, they can be loaded with different molecules and employed as a drug-delivery vehicle. This review focuses on recent advances related to the role of exosomes in asthma disease.

Bronchoalveolar Lavage Fluid-Derived Exosomes: A Novel Role Contributing to Lung Cancer Growth

Exosomes are nanovesicles produced by a number of different cell types and regarded as important mediators of cell-to-cell communication. Although bronchoalveolar lavage fluid (BALF) has been shown to be involved in the development of tumors, its role in lung cancer (LC) remains unclear. In this article, we systemically studied BALF-derived exosomes in LC. C57BL/6 mice were injected with Lewis lung carcinoma cells and exposed to non-typeable Haemophilus influenza (NTHi) lysate. The analysis showed that the growth of lung tumors in these mice was significantly enhanced compared with the control cohort (only exposure to air). Characterization of the exosomes derived from mouse BALF demonstrated elevated levels of tumor necrosis factor alpha and interleukin-6 in mice exposed to NTHi lysates. Furthermore, abnormal BALF-derived exosomes facilitated the development of LC in vitro and in vivo. The internalization of the BALF-derived exosomes contributed to the development of LC tumors. Collectively, our data demonstrated that exosomes in BALF are a key factor involved in the growth and progression of lung cancer.