Intestinal epithelial cell-derived integrin αβ6 plays an important role in the induction of regulatory T cells and inhibits an antigen-specific Th2 response

Organoids and organoid extracellular vesicles-based disease treatment strategies

Organoids are "mini-organs" that self-organize and differentiate from stem cells under in vitro 3D culture conditions, mimicking the spatial structure and function of tissues in vivo. Extracellular vesicles (EVs) are nanoscale phospholipid bilayer vesicles secreted by living cells, rich in bioactive molecules, with excellent biocompatibility and low immunogenicity. Compared to EVs, organoid-derived EVs (OEVs) exhibit higher yield and enhanced biological functions. Organoids possess stem cell characteristics, and OEVs are capable of delivering active substances, making both highly promising for medical applications. In this review, we provide an overview of the fundamental biological principles of organoids and OEVs, and discuss their current applications in disease treatment. We then focus on the differences between OEVs and traditional EVs. Subsequently, we present methods for the engineering modification of OEVs. Finally, we critically summarize the advantages and challenges of organoids and OEVs. In conclusion, we believe that a deeper understanding of organoids and OEVs will provide innovative solutions to complex diseases.

Allergen specific immunotherapy regulates macrophage property in the airways

BACKGROUND

Allergen specific immunotherapy (AIT) has been widely used in allergy clinics. The therapeutic effects of it are to be improved. Macrophages occupy the largest proportion of airway immune cells. The aim of this study is to measure the effects of nasal instillation AIT (nAIT) on airway allergy by regulating macrophage functions.

METHODS

An airway allergy mouse model was established with the ovalbumin-alum protocol. nAIT was conducted for mice with airway allergy through nasal instillation. The effects of nAIT were compared with subcutaneous injection AIT (SCIT) and sublingual AIT (SLIT).

RESULTS

Mice with airway allergy showed the airway allergic response, including lung inflammation, airway hyper responsiveness, serum specific IgE, increase in the amounts of eosinophil peroxidase, mouse mast cell protease-1, and Th2 cytokines in bronchoalveolar lavage fluid. nAIT had a much better therapeutic effect on the airway allergic response than SCIT and SLIT. Mechanistically, we observed better absorption of allergen in macrophages, better production of IL-10 by macrophages, and better immune suppressive functions in macrophages in mice received nAIT than SCIT and SLIT.

CONCLUSIONS

The nAIT has a much better therapeutic effect on suppressing the airway allergic response, in which macrophages play a critical role.

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.

Blockade of exosome release alleviates the hypersensitive reaction by influencing the T helper cell population in cow's milk allergic mice

The aim of this work was to evaluate the ameliorative effects of exosome biogenesis in cow's milk allergy (CMA) response. In this context, BALB/c mice were systemically sensitized with cow's milk proteins plus an aluminum adjuvant to induce CMA. The inhibitor GW4869 of exosome biogenesis was added before sensitization and then the anaphylactic reactions were evaluated both in vivo (clinical score and body temperature) and in vitro (serum histamine, allergen-specific antibodies, cytokines by ELISA and cell analysis by flow cytometry) to explore the role of exosomes in the development of CMA. Nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) showed that the size distribution and morphology of CMA-derived exosomes were not changed after GW4869 preconditioning, and the concentration of exosomes was much lower than that of the CMA group. In the GW4869 group, inhibition of release of exosomes modulated the induction of T helper 2 cell (Th2)-related substances, with a decrease in histamine and allergen-specific immunoglobulin (Ig) E, and the expression of Th1, Th2, and Th17 cells all decreased as well. Moreover, the experimental data were integrated by means of principal component analysis (PCA) to give an overview that the percentage of Th cells and concentrations of cytokines were more influenced by GW4869 treatment. These data for the first time demonstrated that exosomes are involved in the development of CMA and the blockade of exosome release with GW4869 suppressed the IgE-mediated immune response in CMA.

Cellular evidence of communication strategies for small intestinal high endothelial cells: Ultrastructural insights of nano-scale exosomes and autophagy

Although several immune related cells of small intestine play an essential role in the intestinal homeostasis. However, information related to ultrastructural evidence of Nano-scale exosomes-multivesicular bodies and autophagic pathway in the high endothelial cells (HECs) of the small intestine in laying birds is still ambiguous. In present study, the HECs secreted the early endosome (ee), late endosome (le) and multivesicular bodies (MVBs) in the lamina propria of layer small intestine was confirmed by transmission electron microscopy. Besides that, in the cytoplasm of HECs showed many autophagosomes were directly associated with lysosomes and mitochondria. Further, the immunohistochemistry and immunofluorescence results showed that, the immunoreactivity and immuno-signaling of Nano-scale exosome related proteins, cluster of differentiation (CD63) and tumor susceptibility gene (TSG101), and autophagic related proteins, autophagic related gene (ATG7) and microtubule-associated protein light chain (LC3) were strong positive expression in the lamina propria of small intestine. These results prove that HECs play a well-known immunological role in the maintenance of intestinal homeostasis. In summary, these findings indicate that the small intestine's HECs have developed an innovative way of communication.

Extracellular Vesicles: Novel Potential Therapeutic Agents in Inflammatory Bowel Diseases

Patients affected by inflammatory bowel diseases (IBD) can nowadays benefit from a growing number of pharmacological options. However, in moderate-to-severe cases, the therapeutic response is still far from optimal, and treatment changes and optimizations are often required. Thus, researchers in this field are strongly engaged in studies aiming to identify new potential therapeutic targets. Extracellular vesicles (EVs) are tiny subcellular bodies with a phospholipid bilayer envelope containing bioactive molecules, which are released from different cells and are involved in intercellular communication. Recent pre-clinical data show their emerging role in the pathogenesis and treatment of IBD. In our review, we summarize current evidence about the function of EVs as active therapeutic agents in ulcerative colitis and Crohn's disease, analyzing the properties of EVs derived from different cellular sources and the mechanisms through which they may improve intestinal inflammation.

Goblet cell-associated antigen passage: A gatekeeper of the intestinal immune system

Effective delivery of luminal antigens to the underlying immune system is the initial step in generating antigen-specific responses in the gut. However, a large body of information regarding the immune response activation process remains unknown. Recently, goblet cells (GCs) have been reported to form goblet cell-associated antigen passages (GAPs). Luminal antigens can be transported inside GAPs and reach subepithelial immune cells to induce antigen-specific immune responses, contributing largely to gut homeostasis and the prevention of some intestinal diseases like allergic enteritis and bacterial translocation. In this article, we summarized recent observations on the formation of intestinal GAPs and their roles in mucosal immunity. We hope that this review can offer a fresh perspective and valuable insights for clinicians and researchers interested in studying the intestinal immune system.

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.

Application of Extracellular Vesicles in Allergic Rhinitis: A Systematic Review

The pathophysiology of allergic rhinitis (AR), one of the most common diseases in the world, is still not sufficiently understood. Extracellular vesicles (EVs), which are secreted by host and bacteria cells and take part in near and distant intracellular communication, can provide information about AR. Recently, attention has been drawn to the potential use of EVs as biomarkers, vaccines, or transporters for drug delivery. In this review, we present an up-to-date literature overview on EVs in AR to reveal their potential clinical significance in this condition. A comprehensive and systematic literature search was conducted following PRISMA statement guidelines for original, completed articles, available in English concerning EVs and AR. For this purpose, PubMed/MEDLINE, Scopus, Web of Science, and Cochrane, were searched up until 10 Novenmber 2022. From 275 records, 18 articles were included for analysis. The risk of bias was assessed for all studies as low or moderate risk of overall bias using the Office and Health Assessment and Translation Risk of Bias Rating Tool for Human and Animal Studies. We presented the role of exosomes in the pathophysiology of AR and highlighted the possibility of using exosomes as biomarkers and treatment in this disease.

Extracellular Vesicles: The Next Generation Theranostic Nanomedicine for Inflammatory Bowel Disease

The recent rapid development in the field of extracellular vesicles (EVs) based nanotechnology has provided unprecedented opportunities for nanomedicine platforms. As natural nanocarriers, EVs such as exosomes, exosome-like nanoparticles and outer membrane vesicles (OMVs), have unique structure/composition/morphology characteristics, and show excellent physical and chemical/biochemical properties, making them a new generation of theranostic nanomedicine. Here, we reviewed the characteristics of EVs from the perspective of their formation and biological function in inflammatory bowel disease (IBD). Moreover, EVs can crucially participate in the interaction and communication of intestinal epithelial cells (IECs)-immune cells-gut microbiota to regulate immune response, intestinal inflammation and intestinal homeostasis. Interestingly, based on current representative examples in the field of exosomes and exosome-like nanoparticles for IBD treatment, it is shown that plant, milk, and cells-derived exosomes and exosome-like nanoparticles can exert a therapeutic effect through their components, such as proteins, nucleic acid, and lipids. Moreover, several drug loading methods and target modification of exosomes are used to improve their therapeutic capability. We also discussed the application of exosomes and exosome-like nanoparticles in the treatment of IBD. In this review, we aim to better and more clearly clarify the underlying mechanisms of the EVs in the pathogenesis of IBD, and provide directions of exosomes and exosome-like nanoparticles mediated for IBD treatment.

Reciprocal Interactions Between Regulatory T Cells and Intestinal Epithelial Cells

It has been well established that Foxp3+ regulatory T cells (Treg cells) play a crucial role for immune repression and tolerance, protecting the body from autoimmunity and inflammation. Previous studies indicate that intestinal Treg cells are one specialized population of Treg cells, distinct from those in other organ compartments, both functionally and phenotypically. Specific external and internal signals, particularly the presence of microbiota, shape these Treg cells to better cooperate with the gut ecosystem, controlling intestinal physiology. The integrity of intestinal epithelial barrier represents a key feature of gut immune tolerance, which can be regulated by multiple factors. Emerging evidence suggests that bidirectional interactions between gut epithelium and resident T cells significantly contribute to intestinal barrier function. Understanding how Treg cells regulate intestinal barrier integrity provides insights into immune tolerance-mediated mucosal homeostasis, which can further illuminate potential therapeutic strategies for treating inflammatory bowel disease and colon cancer.

Extracellular vesicles derived from small intestinal lamina propria reduce antigen-specific immune response

BACKGROUND/AIMS

Extracellular vesicles (EVs) are secreted from various types of cells and have specific functions related to their origin. EVs are observed in the small intestinal lamina propria (lpEVs), but their function remains unclear. This study aimed to investigate the role of lpEVs.

METHODS

LpEVs were isolated from antigen (ovalbumin [OVA])-fed mice (lpEVs/OVA), and administrated to the naïve mice for 5 days before induction of lung inflammation. Afterwards, the mice were sensitized and challenged with OVA to evaluate the role of lpEVs/OVA in the regulation of immune tolerance.

RESULTS

The isolated lpEVs/OVA were sphere-shaped, bi-layered vesicles of approximately 50 to 100 nm in size. The vesicles expressed CD81, A33 antigen, and major histocompatibility complex (MHC) class II on the surface. When administrated to naïve mice, the lpEVs/OVA migrated to the spleen. Intraperitoneal lpEVs/OVA administration to naïve mice decreased the immune response against sensitized antigen in a CD4+FoxP3+T cell-dependent manner.

CONCLUSION

EVs are actively secreted from small intestinal epithelial cells to deliver information about orally administered antigens to immune cells, which will facilitate the modulation of the immune response by acting as an intercellular communicasome.

T cell activator-carrying extracellular vesicles induce antigen-specific regulatory T cells

The mechanism of antigen-specific regulatory T cell (T_reg ) induction is not yet fully understood. Curcumin has an immune regulatory function. This study aims to induce antigen-specific T_regs by employing extracellular vesicles (EVs) that carry two types of T cell activators. Two types of T cell activators, ovalbumin (OVA)/major histocompatibility complex-II (MHC-II) and tetramethylcurcumin (FLLL31) (a curcumin analog) were carried by dendritic cell-derived extracellular vesicles, designated OFexo. A murine model of allergic rhinitis (AR) was developed with OVA as the specific antigen. AR mice were treated with a nasal instillation containing OFexo. We observed that OFexo recognized antigen-specific T cell receptors (TCR) on CD4⁺ T cells and enhanced Il10 gene transcription in CD4⁺ T cells. Administration of the OFexo-containing nasal instillation induced antigen-specific type 1 T_regs (Tr1 cells) in the mouse airway tissues. OFexo-induced Tr1 cells showed immune suppressive functions on CD4⁺ T cell proliferation. Administration of OFexo efficiently alleviated experimental AR in mice. In conclusion, OFexo can induce antigen-specific Tr1 cells that can efficiently alleviate experimental AR. The results suggest that OFexo has the translational potential to be employed for the treatment of AR or other allergic disorders.

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.

Immune modulation mediated by extracellular vesicles of intestinal organoids is disrupted by opioids

Extracellular vesicles (EVs) are effective mediators of intercellular communications between enterocytes and immune cells. The current study showed that EVs isolated from mouse and human intestinal organoids modulated inflammatory responses of various immune cells including mouse bone-marrow derived-macrophages, dendritic cells, microglia cells, and human monocytes. EVs suppressed LPS-elicited cytokine production in these cells while morphine abolished EVs' immune modulatory effects. Microarray analysis showed that various microRNAs, especially Let-7, contributed to EV-mediated immune modulation. Using murine models, we showed that injection of EVs derived from intestinal organoids reduced endotoxin-induced systemic inflammation and alleviated the symptoms of DSS-induced colitis. EVs derived from morphine-treated organoids failed to suppress the immune response in both these models. Our study suggests that EVs derived from intestinal crypt cells play crucial roles in maintaining host homeostasis and opioid use is a risk factor for exacerbating inflammation in patients with inflammatory diseases such as sepsis and colitis.

Epithelial cell-derived CD83 restores immune tolerance in the airway mucosa by inducing regulatory T-cell differentiation

The mechanism of generation of regulatory T cells (Treg) remains incompletely understood. Recent studies show that CD83 has immune regulatory functions. This study aims to investigate the role of epithelial cell-derived CD83 in the restoration of immune tolerance in the airway mucosa by inducing the Treg differentiation. In this study, CD83 and ovalbumin (OVA)-carrying exosomes were generated from airway epithelial cells. An airway allergy mouse model was developed to test the role of CD83/OVA-carrying exosomes in the suppression of airway allergy by inducing Treg generation. We observed that mouse airway epithelial cells expressed CD83 that could be up-regulated by CD40 ligand. The CD83 deficiency in epithelial cells retarded the Treg generation in the airway mucosa. CD83 up-regulated transforming growth factor-β-inducible early gene 1 expression in CD4+ T cells to promote Foxp3 expression. Exposure of primed CD4+ T cells to CD83/OVA-carrying exosomes promoted antigen-specific Treg generation. Administration of CD83/OVA-carrying exosomes inhibited experimental airway allergic response. In summary, airway epithelial cells express CD83 that is required in the Treg differentiation in the airway mucosa. Administration of CD83/OVA-carrying exosomes can inhibit airway allergy that has the translation potential in the treatment of airway allergic disorders.

Exosomes in Intestinal Inflammation

Exosomes are 30–150 nm sized vesicles released by a variety of cells, and are found in most physiological compartments (feces, blood, urine, saliva, breast milk). They can contain different cargo, including nucleic acids, proteins and lipids. In Inflammatory Bowel Disease (IBD), a distinct exosome profile can be detected in blood and fecal samples. In addition, circulating exosomes can carry targets on their surface for monoclonal antibodies used as IBD therapy. This review aims to understand the exosome profile in humans and other mammals, the cargo contained in them, the effect of exosomes on the gut, and the application of exosomes in IBD therapy.

Modulating oxidative stress counteracts specific antigen-induced regulatory T-cell apoptosis in mice

Treg are known to have a central role in orchestrating immune responses, but less is known about the destiny of Treg after being activated by specific Ags. This study aimed to investigate the role of superoxide dismutase, an active molecule in the regulation of oxidative stress in the body, in the prevention of Treg apoptosis induced by specific Ags. Ag-specific Tregs were isolated from the DO11.10 mouse intestine. A food allergy mouse model was developed with ovalbumin as the specific Ag and here, we observed that exposure to specific Ag induced Treg apoptosis through converting the precursor of TGF-β to its mature form inside the Tregs. Oxidative stress was induced in Tregs upon exposure to specific Ags, in which Smad3 bound the latency-associated peptide to induce its degradation, converting the TGF-β precursor to its mature form, TGF-β. Suppressing oxidative stress in Tregs alleviated the specific Ag-induced Treg apoptosis in in vitro experiments and suppressed experimental food allergy by preventing the specific Ag-induced Treg apoptosis in the intestine. In conclusion, exposure to specific Ags induces Treg apoptosis and it can be prevented by upregulating superoxide dismutase or suppressing reactive oxidative species in Tregs.

The Charming World of the Extracellular Matrix: A Dynamic and Protective Network of the Intestinal Wall

The intestinal extracellular matrix (ECM) represents a complex network of proteins that not only forms a support structure for resident cells but also interacts closely with them by modulating their phenotypes and functions. More than 300 molecules have been identified, each of them with unique biochemical properties and exclusive biological functions. ECM components not only provide a scaffold for the tissue but also afford tensile strength and limit overstretch of the organ. The ECM holds water, ensures suitable hydration of the tissue, and participates in a selective barrier to the external environment. ECM-to-cells interaction is crucial for morphogenesis and cell differentiation, proliferation, and apoptosis. The ECM is a dynamic and multifunctional structure. The ECM is constantly renewed and remodeled by coordinated action among ECM-producing cells, degrading enzymes, and their specific inhibitors. During this process, several growth factors are released in the ECM, and they, in turn, modulate the deposition of new ECM. In this review, we describe the main components and functions of intestinal ECM and we discuss their role in maintaining the structure and function of the intestinal barrier. Achieving complete knowledge of the ECM world is an important goal to understand the mechanisms leading to the onset and the progression of several intestinal diseases related to alterations in ECM remodeling.

Chimeric antigen-guiding extracellular vesicles eliminate antigen-specific Th2 cells in subjects with food allergy

Background

Antigen (Ag)-specific T helper (Th)2 cells play a central role in food allergy (FA) pathogenesis. Methods can be used to eliminate Ag-specific Th2 cells that are currently lacking. This study aims to eliminate the Ag-specific Th2 cells with a novel nanoparticle, the mEV (modified extracellular vesicles, that carry a chimeric antigen peptide, MHC II and caspase 3) in a murine FA model.

Methods

mEVs were generated by exposing dendritic cells (DC) to ovalbumin (OVA, a specific Ag) and recombinant caspase 3 (Casp3) in the culture overnight. Exosomes were purified from culture supernatant by the magnetic antibody approach. A murine FA model was developed with OVA as the specific Ag.

Results

Purified mEVs had the molecular markers of extracellular vesicle, CD81, CD63, and CD9, cleaved Casp3 and MHC II/OVA complexes. mEVs specifically bound to the surface of Ag-specific CD4⁺ T cells, induced Ag-specific CD4⁺ T cell apoptosis both in vitro and in vivo as well as increased regulatory T cells in the intestinal tissues. Administration of mEV efficiently suppressed experimental FA.

Conclusions

mEVs carry Ag/MHC II complexes and Casp3, that can induce Ag-specific Th2 cell apoptosis. Administration of mEV can efficiently suppress experimental FA. The results suggest that the mEVs have the translational potential to be used in the treatment of FA and other allergic diseases.

Cell-to-Cell Communication by Host-Released Extracellular Vesicles in the Gut: Implications in Health and Disease

Communication between cells is crucial to preserve body homeostasis and health. Tightly controlled intercellular dialog is particularly relevant in the gut, where cells of the intestinal mucosa are constantly exposed to millions of microbes that have great impact on intestinal homeostasis by controlling barrier and immune functions. Recent knowledge involves extracellular vesicles (EVs) as mediators of such communication by transferring messenger bioactive molecules including proteins, lipids, and miRNAs between cells and tissues. The specific functions of EVs principally depend on the internal cargo, which upon delivery to target cells trigger signal events that modulate cellular functions. The vesicular cargo is greatly influenced by genetic, pathological, and environmental factors. This finding provides the basis for investigating potential clinical applications of EVs as therapeutic targets or diagnostic biomarkers. Here, we review current knowledge on the biogenesis and cargo composition of EVs in general terms. We then focus the attention to EVs released by cells of the intestinal mucosa and their impact on intestinal homeostasis in health and disease. We specifically highlight their role on epithelial barrier integrity, wound healing of epithelial cells, immunity, and microbiota shaping. Microbiota-derived EVs are not reviewed here.

Integrin αvβ6 cooperates with resiquimod to restore antigen-specific immune tolerance in airway allergy

BACKGROUND

Integrin αvβ6 can convert the transforming growth factor (TGF)-β precursor to the mature form. Resiquimod (R848) can generate TGF-β-producing regulatory T cells (Treg). Thus, to concurrent administration of specific antigen and R848 may generate antigen-specific Tregs, that is expected to restore immune tolerance in subjects with airway allergic diseases (AAD).

METHODS

A bio-nanoparticle, designated Rexo, containing an antigen/MHC II complex and R848, was naturally assembled in dendritic cells, that was released as an exosome. An AAD mouse model was developed used to test the effects of Rexo on restoring the immune tolerance in the airways.

RESULTS

Exposure to R848 failed to induce Tregs in the β6-deficient mouse airway tissues, that were successfully induced in wild type mice. The results were validated inin vitro experiments. R848 activated the TLR7/MyD88/p38 signal pathway to increase the αvβ6 levels in CD4⁺ T cells, the αvβ6 then converted the TGF-β precursor to its mature form, and thus, induced Treg generation. Administration of Rexo restored the antigen-specific immune tolerance in the airways manifesting efficiently suppressing experimental AAD by inducing antigen-specific Tregs in the airways and inhibiting antigen-specific Th2 response.

CONCLUSIONS

Rexos can inhibit experimental AAD via inducing antigen-specific Tregs to restore immune tolerance in the airway tissues, suggesting that Rexos have the translational potential to be used in the treatment of AAD.

Specific Ag-guiding nano-vaccines attenuate neutrophil-dominant allergic asthma

Polymorphonuclear neutrophils (PMN) are one fraction of the major inflammatory cells in allergic asthma (asthma, in short); the role of PMN in the asthma pathogenesis is not fully understood yet. This study aims to investigate the effects of specific Ag-guiding exosomes on suppressing the neutrophil-dominant airway inflammation. In this study, BALB/c mice were immunized with ovalbumin plus complete Freund adjuvant to induce an asthma model featured with neutrophil-dominant lung inflammation. The Ag specific PMN (sPMN)-targeting exosomes (tExo), that were exosomes carrying a complex of specific Ag/anti-CD64 Ab and Fas ligand, were constructed to be used to alleviate neutrophilic asthma in mice. We found that sPMNs were the major cellular component in bronchoalveolar lavage fluid (BALF) in asthma mice, while less than 3% PMNs in naive control mice. The sPMNs expressed higher levels of CD64, which formed complexes with Ag-specific IgG (sIgG). The sIgG/CD64 complex-carrying PMNs could be activated upon exposing to specific Ags. Exposure to tExos induced Ag-specific PMNs apoptosis. Administration of tExos efficiently suppressed experimental asthma. We conclude that a fraction of sPMN was identified in the airway of asthma mice. The sPMNs could be activated upon exposure to specific Ags. tExos could induce sPMNs apoptosis, that show the translational potential in the treatment of asthma.

Intestinal Epithelium-Derived Luminally Released Extracellular Vesicles in Sepsis Exhibit the Ability to Suppress TNF-a and IL-17A Expression in Mucosal Inflammation

Sepsis is a systemic inflammatory disorder induced by a dysregulated immune response to infection resulting in dysfunction of multiple critical organs, including the intestines. Previous studies have reported contrasting results regarding the abilities of exosomes circulating in the blood of sepsis mice and patients to either promote or suppress inflammation. Little is known about how the gut epithelial cell-derived exosomes released in the intestinal luminal space during sepsis affect mucosal inflammation. To study this question, we isolated extracellular vesicles (EVs) from intestinal lavage of septic mice. The EVs expressed typical exosomal (CD63 and CD9) and epithelial (EpCAM) markers, which were further increased by sepsis. Moreover, septic-EV injection into inflamed gut induced a significant reduction in the messaging of pro-inflammatory cytokines TNF-α and IL-17A. MicroRNA (miRNA) profiling and reverse transcription and quantitative polymerase chain reaction (RT-qPCR) revealed a sepsis-induced exosomal increase in multiple miRNAs, which putatively target TNF-α and IL-17A. These results imply that intestinal epithelial cell (IEC)-derived luminal EVs carry miRNAs that mitigate pro-inflammatory responses. Taken together, our study proposes a novel mechanism by which IEC EVs released during sepsis transfer regulatory miRNAs to cells, possibly contributing to the amelioration of gut inflammation.

Exosomes carry IL-10 and antigen/MHC II complexes to induce antigen-specific oral tolerance

BACKGROUND

It is known that the immune tolerance can be naturally established in the intestine, while the mechanism by which the immune tolerance development in the intestine is not fully understood yet. Vasoactive intestinal peptides (VIP) has the immune regulatory functions. This study aims to investigate the role of VIP in the immune tolerance development in the intestine.

METHODS

Intestinal epithelial cell (IEC)-derived exosomes were prepared. The exosomes carried IL-10 and antigen/MHC II complexes. VIP-deficient (VIPd) mice and wild type mice were employed to test the role of VIP in the development of immune tolerance in the intestine.

RESULTS

VIPd mice failed to induce type 1 regulatory T cells (Tr1 cells) in the intestine and retarded the establishment of antigen (Ag)-specific immune tolerance. Exposure to VIP in the culture induced IL-10 expression in intestinal epithelial cells (IECs). Exosomes derived from ovalbumin (OVA, used as a specific Ag)/VIP-primed IECs carried IL-10 and OVA/MHC II complexes; these exosomes were designated IL10CARs (IL-10/chimeric antigen receptor-carrying exosomes). IL10CARs could recognize OVA-specific CD4⁺ T cells and converted OVA-specific CD4^± T cells to OVA-specific Tr1 cells. Administration of IL10CARs suppressed experimental food allergy.

CONCLUSIONS

The data show that IL10CARs are capable of suppressing experimental FA by inducing antigen-specific Tr1 cells, which has the translation potential for FA treatment.

Specific antigen-guiding exosomes inhibit food allergies by inducing regulatory T cells

The therapies for food allergy (FA) need to be improved. The generation of inducible regulatory T cells (Tregs) can support immune tolerance in the body. This study aims to suppress experimental FA by inducing Tregs through the employment of modified exosomes (mExosomes). In this study, mExosomes were prepared by incubating dendritic cells with interleukin (IL)-2 and ovalbumin (OVA, used as a specific antigen) in the culture. Exosomes were purified from culture supernatant and used as the mExosomes. A murine FA model was developed to test the effects of mExosomes on the generation of Tregs in the mouse intestinal tissues and inhibiting FA. The results showed that mExosomes, which carried IL-2 and a complex of OVA peptide-major histocompatibility complex class II on the surface of exosomes, bound to OVA-specific CD4⁺ T cells and induced CD4⁺ T cells to differentiate into Tregs. In the FA mouse intestinal tissues, we found low IL-2 levels that were positively correlated with the number of Tregs. Depletion of IL-2 in mice prevented the generation of Tregs. The levels of peroxisome proliferator-activated receptor-γ were increased in the FA intestinal tissues with inhibited IL-2 production. Administration of mExosomes induced Tregs in the intestinal tissues and efficiently suppressed FA in mice. We conclude that the mExosomes can suppress FA in mice through inducing Tregs. The data suggest that the mExosomes have translational potential in the treatment of FA and other allergic disorders.

CARsomes inhibit airway allergic inflammation in mice by inducing antigen-specific Th2 cell apoptosis

BACKGROUND

Skewed T helper (Th)2 response plays a crucial role in the pathogenesis of allergic diseases. The therapeutic efficacy for allergic diseases is unsatisfactory currently. This study aims to regulate the skewed Th2 response with CARsomes.

METHODS

The CARsome consisted of an epitope of Dermatophagoides farina-1 (Derf1), a segment of the anti-DEC205 antibody, the scFv, and an open reading frame of perforin. This fusion protein binds to DEC205 molecule on the surface of exosomes derived from dendritic cells (DC). The effects of CARsome on inducing antigen (Ag)-specific Th2 cell apoptosis were assessed both in vivo and in vitro.

RESULTS

Exposure to CARsomes in the culture induced Ag-specific Th2 cell apoptosis. Injection of CARsomes through the vein puncture also induced Ag-specific Th2 cell apoptosis in the lungs of sensitized mice. CARsomes could induce Ag-specific regulatory T cells. Administration of CARsomes efficiently inhibited experimental allergic airway inflammation.

CONCLUSIONS

The CARsomes can inhibit allergic airway inflammation by inducing Ag-specific Th2 cell apoptosis and induce Ag-specific regulatory T cells. The data suggest that CARsomes have the translational potential to be used to treat allergic airway inflammation.

The Therapeutic Potential of Breast Milk-Derived Extracellular Vesicles

In the past few decades, interest in the therapeutic benefits of exosomes and extracellular vesicles (EVs) has grown exponentially. Exosomes/EVs are small particles which are produced and exocytosed by cells throughout the body. They are loaded with active regulatory and stimulatory molecules from the parent cell including miRNAs and enzymes, making them prime targets in therapeutics and diagnostics. Breast milk, known for years to have beneficial health effects, contains a population of EVs which may mediate its therapeutic effects. This review offers an update on the therapeutic potential of exosomes/EVs in disease, with a focus on EVs present in human breast milk and their remedial effect in the gastrointestinal disease necrotizing enterocolitis. Additionally, the relationship between EV miRNAs, health, and disease will be examined, along with the potential for EVs and their miRNAs to be engineered for targeted treatments.

Extracellular Vesicles with Possible Roles in Gut Intestinal Tract Homeostasis and IBD

The intestinal tract consists of various types of cells, such as epithelial cells, Paneth cells, macrophages, and lymphocytes, which constitute the intestinal immune system and play a significant role in maintaining intestinal homeostasis by producing antimicrobial materials and controlling the host-commensal balance. Various studies have found that the dysfunction of intestinal homeostasis contributes to the pathogenesis of inflammatory bowel disease (IBD). As a novel mediator, extracellular vesicles (EVs) have been recognized as effective communicators, not only between cells but also between cells and the organism. In recent years, EVs have been regarded as vital characters for dysregulated homeostasis and IBD in either the etiology or the pathology of intestinal inflammation. Here, we review recent studies on EVs associated with intestinal homeostasis and IBD and discuss their source, cargo, and origin, as well as their therapeutic effects on IBD, which mainly include artificial nanoparticles and EVs derived from microorganisms.

Multivesicular bodies containing exosomes in immune-related cells of the intestine in zebrafish (Danio rerio): Ultrastructural evidence

Exosomes are secreted from various cells by multivesicular bodies (MVBs) that fuse with the plasma membrane and are involved in the intestinal immune response to maintain intestinal homeostasis. Here, we demonstrate the ultrastructural characteristics of MVBs and their exosomes in immune-related cells of the zebrafish intestine, including goblet cells (GCs), mitochondria-rich cells (MRCs), high endothelial cells (HECs) and lymphocytes. In GCs, MVBs with a low electron density were present under the nucleus. MVBs with exosomes were observed among mucin granules. "Heterogeneous" MVBs were identified within the cytoplasm around mucin granules. MRCs were observed in the intestinal mucosa epithelium, including "open-type" MRCs and "close-type" MRCs. Typical MVBs were identified in these MRCs. MVBs with a variety of exosomes were observed in the HECs of the capillary located in the lamina propria (LP). The HEC basement membrane budded outward to LP cells to form a plurality of basal blebs, later containing a large number of exosomes. MVBs also existed in the LP lymphocytes. A schematic diagram of the ultrastructural distribution of MVBs and their exosomes in the intestinal mucosal immune-related cells was created. Our findings provide cytological evidence for the source and ultrastructural distribution of exosomes within the different intestine cells of zebrafish. Component analysis and immunological functions of exosomes require future study.

The role of the miR1976/CD105/integrin αvβ6 axis in vaginitis induced by Escherichia coli infection in mice

Vaginitis is very common among women, especially women of childbearing age, and is associated with significantly increased risk of preterm birth and pelvic inflammatory diseases. An imbalance in the vaginal flora, the primary cause of vaginitis, promotes the initiation and progression of vaginal infections. However, the responsible mechanisms are still poorly understood. Using a murine vaginitis model of Escherichia coli infection, we demonstrated that decreased expression of microRNA1976 and increased expression of CD105 and integrin αvβ6 were closely associated with the progression of vaginal infection. Importantly, we demonstrated for the first time that the microRNA1976/CD105/integrin αvβ6 axis regulates E. coli-mediated vaginal infection in mice, as evidenced by the finding that E. coli-induced vaginal infection was reversed by microRNA1976 overexpression and exacerbated by CD105 overexpression. The regulation of CD105 and integrin αvβ6 by microRNA1976 was further confirmed in a murine model of vaginitis with adenoviral vector treatment. Taken together, our data suggested that microRNA1976 negatively regulates E. coli-induced vaginal infection in mice at least in part by suppressing CD105 and integrin αvβ6 expression. These findings may provide new insight into the mechanisms of E. coli-induced vaginitis, identify a novel diagnostic biomarker and a potential therapeutic target for flora imbalance-associated vaginitis.

Nasal instillation of probiotic extracts inhibits experimental allergic rhinitis

Aim: Allergic rhinitis (AR) is a common disease. The therapeutic efficacy of AR needs to be improved. This study aims to evaluate the effects of local administration of probiotic extracts on inhibiting experimental AR. Methods: Epithelial cells (ECs) were primed by exposing to Clostridium butyricum extracts (CBe) in the culture to upregulate the expression of IL-10. A mouse AR model was developed to assess the therapeutic potential of CBe in AR. Results: CBe markedly induced the expression of IL-10 in ECs. Co-culture of naive B cells with CBe-primed ECs significantly increased IL-10 expression in the B cells (iB10 cells). The iB10 cells showed immune suppressive function in suppressing effector CD4⁺ T-cell proliferation. Treatment with nasal drops containing CBe efficiently inhibited experimental AR in mice. Conclusion: Local administration of CBe can efficiently inhibit experimental AR.

Integrin-Mediated TGFβ Activation Modulates the Tumour Microenvironment

TGFβ (transforming growth factor-beta) is a pleotropic cytokine with contrasting effects in cancer. In normal tissue and early tumours, TGFβ acts as a tumour suppressor, limiting proliferation and inducing apoptosis. However, these effects are eventually abrogated by the loss or inactivation of downstream signalling within the TGFβ pathway, and in established tumours, TGFβ then acts as a tumour promotor through multiple mechanisms including inducing epithelial-to-mesenchymal transition (EMT), promoting formation of cancer-associated fibroblasts (CAFs) and increasing angiogenesis. TGFβ is secrereted as a large latent complex and is embedded in the extracellular matrix or held on the surface of cells and must be activated before mediating its multiple functions. Thus, whilst TGFβ is abundant in the tumour microenvironment (TME), its functionality is regulated by local activation. The αv-integrins are major activators of latent-TGFβ. The potential benefits of manipulating the immune TME have been highlighted by the clinical success of immune-checkpoint inhibitors in a number of solid tumour types. TGFβ is a potent suppressor of T-cell-mediated immune surveillance and a key cause of resistance to checkpoint inhibitors. Therefore, as certain integrins locally activate TGFβ, they are likely to have a role in the immunosuppressive TME, although this remains to be confirmed. In this review, we discussed the role of TGFβ in cancer, the role of integrins in activating TGFβ in the TME, and the potential benefits of targeting integrins to augment immunotherapies.

Human Gut-Associated Natural Killer Cells in Health and Disease

It is well established that natural killer (NK) cells are involved in both innate and adaptive immunity. Indeed, they can recognize molecules induced at the cell surface by stress signals and virus infections. The functions of NK cells in the gut are much more complex. Gut NK cells are not precisely organized in lymphoid aggregates but rather scattered in the epithelium or in the stroma, where they come in contact with a multitude of antigens derived from commensal or pathogenic microorganisms in addition to components of microbiota. Furthermore, NK cells in the bowel interact with several cell types, including epithelial cells, fibroblasts, macrophages, dendritic cells, and T lymphocytes, and contribute to the maintenance of immune homeostasis and development of efficient immune responses. NK cells have a key role in the response to intestinal bacterial infections, primarily through production of IFNγ, which can stimulate recruitment of additional NK cells from peripheral blood leading to amplification of the anti-bacterial immune response. Additionally, NK cells can have a role in the pathogenesis of gut autoimmune inflammatory bowel diseases (IBDs), such as Crohn's Disease and Ulcerative Colitis. These diseases are considered relevant to the generation of gastrointestinal malignancies. Indeed, the role of gut-associated NK cells in the immune response to bowel cancers is known. Thus, in the gut immune system, NK cells play a dual role, participating in both physiological and pathogenic processes. In this review, we will analyze the known functions of NK cells in the gut mucosa both in health and disease, focusing on the cross-talk among bowel microenvironment, epithelial barrier integrity, microbiota, and NK cells.

Delayed-Type Hypersensitivity Underlying Casein Allergy Is Suppressed by Extracellular Vesicles Carrying miRNA-150

In patients with non-IgE-mediated milk allergy, a cellular mechanism of delayed-type hypersensitivity (DTH) is considered. Recent findings prove that cell-mediated reactions can be antigen-specifically inhibited by extracellular vesicles (EVs) carrying miRNA-150. We sought to establish a new mouse model of DTH to casein and test the possibility of antigen-specific suppression of the inflammatory reaction. To produce soluble antigenic peptides, casein was subjected to alkaline hydrolysis. DTH reaction to casein was induced in CBA, C57BL/6, and BALB/c mice by intradermal (id) injection of the antigen. Cells collected from spleens and lymph nodes were positively or negatively selected and transferred to naive recipients intravenously (iv). CBA mice were tolerized by iv injection of mouse erythrocytes conjugated with casein antigen and following id immunization with the same antigen. Suppressive EVs were harvested from cell cultures and serum of tolerized donors by means of ultrafiltration and ultracentrifugation for further therapeutic utilization. The newly established mouse model of DTH to casein was mediated by CD4+ Th1 cells and macrophages, while EVs produced by casein-tolerized animals effectively suppressed effector cell response, in an miRNA-150-dependent manner. Altogether, our observations contribute to the current understanding of non-IgE-mediated allergy to casein and of the possibilities to downregulate this reaction.

Connexins and Integrins in Exosomes

Connexins and integrins, the two structurally and functionally distinct families of transmembrane proteins, have been shown to be inter-connected by various modes of cross-talk in cells, such as direct physical coupling via lateral contact, indirect physical coupling via actin and actin-binding proteins, and functional coupling via signaling cascades. This connexin-integrin cross-talk exemplifies a biologically important collaboration between channels and adhesion receptors in cells. Exosomes are biological lipid-bilayer nanoparticles secreted from virtually all cells via endosomal pathways into the extracellular space, thereby mediating intercellular communications across a broad range of health and diseases, including cancer progression and metastasis, infection and inflammation, and metabolic deregulation. Connexins and integrins are embedded in the exosomal membranes and have emerged as critical regulators of intercellular communication. This concise review article will explain and discuss recent progress in better understanding the roles of connexins, integrins, and their cross-talk in cells and exosomes.

Micro RNA-19a interferes with IL-10 expression in peripheral dendritic cells of patients with nasal polyposis

The pathogenesis of nasal polyp is to be further investigated. Micro RNA (miR) plays a role in the development of allergic inflammation. Interleukin (IL)-10-producing dendritic cells (DC) have immune tolerogenic properties. This study test a hypothesis that miR-17-92 cluster is associated with suppressing IL-10 in peripheral DC. In this study, peripheral blood samples were obtained from 26 patients with nasal polyp. The CD11c DCs were isolated from the blood samples and analyzed for the expression of IL-10. We observed that, as compared with healthy subjects, the IL-10 expression in peripheral DC was significantly lower in polyp patients. The levels of miR-19a, but not the rest 5 members of the miR-17-92 cluster, were markedly higher in DCs in polyp group. Exposure to recombinant IL-4 suppressed the IL-10 expression in DCs, which was abolished by blocking histone deacetylase-11 or knocking down the miR-19a gene in DCs. We conclude that miR-19a plays a critical role in the suppression of IL-10 in peripheral DCs, which may be a target in the immune therapy for nasal polyp.

Integrin αvβ6: Structure, function and role in health and disease

Integrins are cell surface receptors that traditionally mediate cell-to-extracellular matrix and cell-to-cell adhesion. They can, however, also bind a large repertoire of other molecules. Integrin αvβ6 is exclusively expressed in epithelial cells where it can, for example, serve as a fibronectin receptor. However, its hallmark function is to activate transforming growth factor-β1 (TGF-β1) to modulate innate immune surveillance in lungs and skin and along the gastrointestinal tract, and to maintain epithelial stem cell quiescence. The loss of αvβ6 integrin function in mice and humans leads to an altered immune response in lungs and skin, amelogenesis imperfecta, periodontal disease and, in some cases, alopecia. Elevated αvβ6 integrin expression and aberrant TGF-β1 activation and function are associated with organ fibrosis and cancer. Therefore, αvβ6 integrin serves as an attractive target for cancer imaging and for fibrosis and cancer therapy.

Extracellular vesicles regulate immune responses and cellular function in intestinal inflammation and repair

Tightly controlled communication among the various resident and recruited cells in the intestinal tissue is critical for maintaining tissue homeostasis, re-establishment of the barrier function and healing responses following injury. Emerging evidence convincingly implicates extracellular vesicles (EVs) in facilitating this important cell-to-cell crosstalk by transporting bioactive effectors and genetic information in healthy tissue and disease. While many aspects of EV biology, including release mechanisms, cargo packaging, and uptake by target cells are still not completely understood, EVs contribution to cellular signaling and function is apparent. Moreover, EV research has already sparked a clinical interest, as a potential diagnostic, prognostic and therapeutic tool. The current review will discuss the function of EVs originating from innate immune cells, namely, neutrophils, monocytes and macrophages, as well as intestinal epithelial cells in healthy tissue and inflammatory disorders of the intestinal tract. Our discussion will specifically emphasize the contribution of EVs to the regulation of vascular and epithelial barrier function in inflamed intestines, wound healing, as well as trafficking and activity of resident and recruited immune cells.

Crosstalk between intestinal epithelial cell and adaptive immune cell in intestinal mucosal immunity

Constantly challenged by luminal bacteria, intestinal epithelium forms both a physical and biochemical defense against pathogens. Besides, intestinal epithelium senses dynamic and continuous changes in luminal environment and transmits signals to subjacent immune cells accordingly. It has been long accepted that adaptive immune cells fulfill their roles partly by modulating function of intestinal epithelial cells. Recent studies have brought up the proposal that intestinal epithelial cells also actively participate in the regulation of adaptive immunity, especially CD4+ adaptive T cells, which indicates that there is reciprocal crosstalk between intestinal epithelial cells and adaptive immune cells, and the crosstalk may play important role in intestinal mucosal immunity. This Review makes a comprehensive summary about crosstalk between intestinal epithelial cells and CD4+ adaptive T cells in intestinal immunity. Special attention would be given to their implications in inflammatory bowel disease pathogenesis and potential therapeutic targets.

Arginine-Glycine-Aspartate-Binding Integrins as Therapeutic and Diagnostic Targets

Arginine-glycine-aspartate (RGD)-binding integrins, including αvβ1, αvβ3, αvβ5, αvβ6, αvβ8, α5β1, αIIbβ3, and α8β1, recognize the tripeptide motif RGD in their ligands. RGD-binding integrins are involved in various cell functions, including cell proliferation, survival, differentiation, and motility that are critically important to both health and disease. The diagnostic and therapeutic value of some RGD-binding integrin inhibitors are either clinically proven or at different stages of development. In this review, we first summarized the structure and signaling characteristics of RGD-binding integrins. We then discussed the functions of RGD-binding integrins and their association with human disease. Finally, we recapitulated the research efforts and clinical trials of targeting RGD-binding integrins for the diagnosis and treatment of human disease. This comprehensive review of the current advances in RGD-binding integrins could assist scientists and clinicians in gaining a complete understanding of this group of molecules. It can also contribute to the design of new projects to further advance this field of research and to better apply the research results to benefit patients in clinical practice.

Exosome in intestinal mucosal immunity

Intercellular communication of immune cells is critical to elicit efficient inflammatory responses. In intestinal mucosa, imbalance in pro-inflammatory and anti-inflammatory mediators, especially cytokines and chemokines, characterizes the underlying immune mechanisms of inflammatory bowel disease. Exosomes, small membrane vesicles secreted into the extracellular environment, are emerging as another important intercellular messenger in immune responses. A major recent breakthrough in this field unveils the capacity of exosomes to mediate the functional transfer of genetic materials (mRNAs and miRNAs) between immune cells. RAB27A and RAB27B are two small GTPases involved in exosome secretion. With respect to intestinal mucosal immunity, increased number of RAB27A-positive immune cells and RAB27B-positive immune cells are demonstrated in the colonic mucosa of patients with active ulcerative colitis as compared with that of healthy controls. This indicates the important role of exosome-mediated immune responses in the pathogenesis of inflammatory bowel disease. Here, we will discuss the immune properties of exosomes and recent advances in their function with a special focus on intestinal mucosal immunity.

Epithelial cell-derived micro RNA-146a generates interleukin-10-producing monocytes to inhibit nasal allergy

The aberrant immunity plays an important role in the pathogenesis of allergic diseases. Micro RNAs (miR) are involved in regulating the immunity in the body. This study aims to test a hypothesis that miR-146a induces the expression of interleukin (IL)-10 in monocytes (Mos). In this study, the levels of miR-146a were determined by real time RT-PCR. The IL-10⁺ Mos were evaluated by flow cytometry. The miR-146a-laden exosomes were generated with RPMI2650 cells (an airway epithelial cell line). An allergic rhinitis mouse model was developed. The results showed that nasal epithelial cells expressed miR-146a, which was markedly lower in the nasal epithelial cells of patients with nasal allergy than that in healthy controls. Exposure to T helper (Th)2 cytokines suppressed the levels of miR-146a in the nasal epithelial cells. The nasal epithelial cell-derived miR-146a up regulated the expression of IL-10 in Mos. The inducible IL-10⁺ Mos showed an immune suppressor effect on the activities of CD4⁺ effector T cells and the Th2 polarization in a mouse model of allergic rhinitis. In summary, nasal epithelial cells express miR-146a, the latter is capable of inducing IL-10 expression in Mos, which suppress allergic reactions in the mouse nasal mucosa.

Esophageal cancer-derived microvesicles induce regulatory B cells

The role of B cells in the generation of cancer-immune tolerance is unclear. This study aims to investigate the role of cancer-derived microvesicles (Mvcs) in the generation of transforming growth factor (TGF)-β(+) B cells. In this study, esophageal cancer (Eca) cells were isolated from surgically removed cancer tissue. Mvcs were purified from the culture supernatant and characterized by Western blotting. The immune suppression assay was carried out with a cell culture model and flow cytometry. The results showed that Eca-derived Mvcs were LAMP1 positive and carried MMP9. Exposure to the Mvcs induces naive B cells to differentiate into TGF-β-producing regulatory B cells; the latter show immune suppressor functions on CD8(+) T-cell proliferation. In conclusion, Eca-derived Mvc can induce TGF-β(+) B cells; the latter suppress CD8(+) T-cell activities. The MMP9-laden Mvcs may be a new therapeutic target in the treatment of Eca.

Thrombospondin-1 (TSP1)-producing B cells restore antigen (Ag)-specific immune tolerance in an allergic environment

Restoration of the antigen (Ag)-specific immune tolerance in an allergic environment is refractory. B cells are involved in immune regulation. Whether B cells facilitate the generation of Ag-specific immune tolerance in an allergic environment requires further investigation. This paper aims to elucidate the mechanism by which B cells restore the Ag-specific immune tolerance in an allergic environment. In this study, a B cell-deficient mouse model was created by injecting an anti-CD20 antibody. The frequency of tolerogenic dendritic cell (TolDC) was assessed by flow cytometry. The levels of cytokines were determined by enzyme-linked immunosorbent assay. The expression of thrombospondin-1 (TSP1) was assessed by quantitative real-time RT-PCR, Western blotting, and methylation-specific PCR. The results showed that B cells were required in the generation of the TGF-β-producing TolDCs in mice. B cell-derived TSP1 converted the latent TGF-β to the active TGF-β in DCs, which generated TGF-β-producing TolDCs. Exposure to IL-13 inhibited the expression of TSP1 in B cells by enhancing the TSP1 gene DNA methylation. Treating food allergy mice with Ag-specific immunotherapy and IL-13 antagonists restored the generation of TolDCs and enhanced the effect of specific immunotherapy. In conclusion, B cells play a critical role in the restoration of specific immune tolerance in an allergic environment. Blocking IL-13 in an allergic environment facilitated the generation of TolDCs and enhanced the therapeutic effect of immunotherapy.

The αvβ6 integrin is transferred intercellularly via exosomes

Exosomes, cell-derived vesicles of endosomal origin, are continuously released in the extracellular environment and play a key role in intercellular crosstalk. In this study, we have investigated whether transfer of integrins through exosomes between prostate cancer (PrCa) cells occurs and whether transferred integrins promote cell adhesion and migration. Among others, we have focused on the αvβ6 integrin, which is not detectable in normal human prostate but is highly expressed in human primary PrCa as well as murine PrCa in Pten(pc-/-) mice. After confirming the fidelity of the exosome preparations by electron microscopy, density gradient, and immunoblotting, we determined that the αvβ6 integrin is actively packaged into exosomes isolated from PC3 and RWPE PrCa cell lines. We also demonstrate that αvβ6 is efficiently transferred via exosomes from a donor cell to an αvβ6-negative recipient cell and localizes to the cell surface. De novo αvβ6 expression in an αvβ6-negative recipient cell is not a result of a change in mRNA levels but is a consequence of exosome-mediated transfer of this integrin between different PrCa cells. Recipient cells incubated with exosomes containing αvβ6 migrate on an αvβ6 specific substrate, latency-associated peptide-TGFβ, to a greater extent than cells treated with exosomes in which αvβ6 is stably or transiently down-regulated by shRNA or siRNA, respectively. Overall, this study shows that exosomes from PrCa cells may contribute to a horizontal propagation of integrin-associated phenotypes, which would promote cell migration, and consequently, metastasis in a paracrine fashion.

Cardiac endothelial cell-derived exosomes induce specific regulatory B cells

The mechanism of immune tolerance is to be further understood. The present study aims to investigate the role of the Cardiac endothelial cell (CEC)-derived exosomes in the induction of regulatory B cells. In this study, CECs were isolated from the mouse heart. Exosomes were purified from the culture supernatant of the primary endothelial cells. The suppressor functions of the regulatory B cells were determined by flow cytometry. The results showed that the CEC-derived exosomes carried integrin αvβ6. Exposure to lipopolysaccharide (LPS) induced B cells to express the latent transforming growth factor (TGF)-β, the latter was converted to the active form, TGF-β, by the exosome-derived αvβ6. The B cells released TGF-β in response to re-exposure to the exosomes in the culture, which suppressed the effector T cell proliferation. We conclude that CEC-derived exosomes have the capacity to induce B cells with immune suppressor functions.