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

Organismal mucosal immunology: A perspective through the eyes of game theory

In complex organisms, functional units must interact cohesively to maintain homeostasis, especially within mucosal barriers that house diverse, specialized cell exposed to constant environmental challenges. Understanding how homeostasis at mucosal barriers is maintained and how its disruption can lead to autoimmune diseases or cancer, requires a holistic view. Although omics approaches and systems immunology have become powerful tools, they are not without limitations; interpretations may reflect researchers' assumptions, even if other explanations exist. In this perspective, I propose that applying game theory concepts to mucosal immunology could help interpret complex data, offering fresh perspectives and supporting the exploration of alternative scenarios. By framing the mucosal immune system as a network of strategic interactions with multiple possible outcomes, game theory, which analyzes strategic interactions and decision-making processes, could illuminate novel cell types and functions, cell interactions, and responses to pathogens and commensals, leading to a more comprehensive understanding of immune homeostasis and diseases. In addition, game theory might encourage researchers to consider a broader range of possibilities, reduce the risk of myopic thinking, and ultimately enable a more refined and comprehensive understanding of the complexity of the immune system at mucosal barriers. This perspective aims to introduce game theory as a complementary framework for mucosal immunologists, encouraging them to incorporate these concepts into data interpretation and system modeling.

The therapeutic use of exosomes in children with adenoid hypertrophy accompanied by otitis media with effusion (AHOME): a protocol study

BACKGROUND

The adenoids act as a reservoir of bacterial pathogens and immune molecules, and they are significantly involved in children with otitis media with effusion (OME). As an essential carrier of intercellular substance transfer and signal transduction, exosomes with different biological functions can be secreted by various types of cells. There remains significant uncertainty regarding the clinical relevance of exosomes to OME, especially in its pathophysiologic development. In this study, we will seek to determine the biological functions of exosomes in children with adenoid hypertrophy accompanied by OME (AHOME).

METHODS

The diagnostic criteria for OME in children aged 4-10 years include a disease duration of at least 3 months, type B or C acoustic immittance, and varying degrees of conductive hearing loss. Adenoidal hypertrophy is diagnosed when nasal endoscopy shows at least 60% adenoidal occlusion in the nostrils or when nasopharyngeal lateral X-ray shows A/N > 0.6. Children who meet the indications for adenoidectomy surgery undergo adenoidectomy. Peripheral blood, nasopharyngeal swab, and adenoid tissue will be collected from patients, and the exosomes will be isolated from the samples. Following the initial collection, patients will undergo adenoidectomy and peripheral blood and nasopharyngeal swabs will be collected again after 3 months.

EXPECTED RESULTS

This study aims to identify differences in exosomes from preoperative adenoid tissue and peripheral blood samples between children with AHOME and those with adenoid hypertrophy alone. Additionally, it seeks to determine changes in microbial diversity in adenoid tissue between these groups.

CONCLUSIONS

The findings are expected to provide new insights into the diagnosis and treatment of OME, to identify novel biomarkers, and to enhance our understanding of the pathophysiology of OME, potentially leading to the development of innovative diagnostic and therapeutic approaches.

Multilevel Proteomic Profiling of Colorectal Adenocarcinoma Caco-2 Cell Differentiation to Characterize an Intestinal Epithelial Model

Emergent advancements on the role of the intestinal microbiome for human health and disease necessitate well-defined intestinal cellular models to study and rapidly assess host, microbiome, and drug interactions. Differentiated Caco-2 cell line is commonly utilized as an epithelial model for drug permeability studies and has more recently been utilized for investigating host-microbiome interactions. However, its suitability to study such interactions remains to be characterized. Here, we employed multilevel proteomics to demonstrate that both spontaneous and butyrate-induced Caco-2 differentiations displayed similar protein and pathway changes, including the downregulation of proteins related to translation and proliferation and upregulation of functions implicated in host-microbiome interactions, such as cell adhesion, tight junction, extracellular vesicles, and responses to stimuli. Lysine acetylomics revealed that histone protein acetylation levels were decreased along with cell differentiation, while the acetylation in proteins associated with mitochondrial functions was increased. This study also demonstrates that, compared to spontaneous differentiation methods, butyrate-containing medium accelerates Caco-2 differentiation, with earlier upregulation of proteins related to host-microbiome interactions, suggesting its superiority for assay development using this intestinal model. Altogether, this multiomics study emphasizes the controlled progression of Caco-2 differentiation toward a specialized intestinal epithelial-like cell and establishes its suitability for investigating the host-microbiome interactions.

Therapeutic potential of extracellular vesicles from diverse sources in cancer treatment

Cancer, a prevalent and complex disease, presents a significant challenge to the medical community. It is characterized by irregular cell differentiation, excessive proliferation, uncontrolled growth, invasion of nearby tissues, and spread to distant organs. Its progression involves a complex interplay of several elements and processes. Extracellular vesicles (EVs) serve as critical intermediaries in intercellular communication, transporting critical molecules such as lipids, RNA, membrane, and cytoplasmic proteins between cells. They significantly contribute to the progression, development, and dissemination of primary tumors by facilitating the exchange of information and transmitting signals that regulate tumor growth and metastasis. However, EVs do not have a singular impact on cancer; instead, they play a multifaceted dual role. Under specific circumstances, they can impede tumor growth and influence cancer by delivering oncogenic factors or triggering an immune response. Furthermore, EVs from different sources demonstrate distinct advantages in inhibiting cancer. This research examines the biological characteristics of EVs and their involvement in cancer development to establish a theoretical foundation for better understanding the connection between EVs and cancer. Here, we discuss the potential of EVs from various sources in cancer therapy, as well as the current status and future prospects of engineered EVs in developing more effective cancer treatments.

Cargo exchange between human and bacterial extracellular vesicles in gestational tissues: a new paradigm in communication and immune development

Host-bacteria and bacteria-bacteria interactions can be facilitated by extracellular vesicles (EVs) secreted by both human and bacterial cells. Human and bacterial EVs (BEVs) propagate and transfer immunogenic cargos that may elicit immune responses in nearby or distant recipient cells/tissues. Hence, direct colonization of tissues by bacterial cells is not required for immunogenic stimulation. This phenomenon is important in the feto-maternal interface, where optimum tolerance between the mother and fetus is required for a successful pregnancy. Though the intrauterine cavity is widely considered sterile, BEVs from diverse sources have been identified in the placenta and amniotic cavity. These BEVs can be internalized by human cells, which may help them evade host immune surveillance. Though it appears logical, whether bacterial cells internalize human EVs or human EV cargo is yet to be determined. However, the presence of BEVs in placental tissues or amniotic cavity is believed to trigger a low-grade immune response that primes the fetal immune system for ex-utero survival, but is insufficient to disrupt the progression of pregnancy or cause immune intolerance required for adverse pregnancy events. Nevertheless, the exchange of bioactive cargos between human and BEVs, and the mechanical underpinnings and health implications of such interactions, especially during pregnancy, are still understudied. Therefore, while focusing on the feto-maternal interface, we discussed how human cells take up BEVs and whether bacterial cells take up human EVs or their cargo, the exchange of cargos between human and BEVs, host cell (feto-maternal) inflammatory responses to BEV immunogenic stimulation, and associations of these interactions with fetal immune priming and adverse reproductive outcomes such as preeclampsia and preterm birth.

Lactobacillus Reuteri Vesicles Regulate Mitochondrial Function of Macrophages to Promote Mucosal and Cutaneous Wound Healing

The interplay between bacteria and their host influences the homeostasis of the human immune microenvironment, and this reciprocal interaction also affects the process of tissue damage repair. A variety of immunomodulatory commensal bacteria reside in the body, capable of delivering membrane vesicles (MVs) to host cells to regulate the local immune microenvironment. This research revealed, for the initial time, the significant enhancement of mucosal and cutaneous wound healing by MVs secreted by the human commensal Lactobacillus reuteri (RMVs) through modulation of the inflammatory environment in wound tissue. Local administration of RMVs reduces the proportion of pro-inflammatory macrophages in inflamed tissues and mitigates the level of local inflammation, thereby facilitating the healing of oral mucosa and cutaneous wounds. The elevated oxidative stress levels in activated pro-inflammatory macrophages can be modulated by RMVs, resulting in phenotypic transformation of macrophages. Furthermore, 3-hydroxypropionaldehyde present in RMVs can decrease the mitochondrial permeability of macrophages and stabilize the mitochondrial membrane potential, thereby promoting the conversion of macrophages to an anti-inflammatory phenotype. This study pioneers the significance of commensal bacterial MVs in tissue injury repair and presents a novel concept for the repair of tissue damage.

Effects of Salmonella Outer Membrane Vesicles on Intestinal Microbiota and Intestinal Barrier Function

Salmonella enterica is one of the most important zoonotic pathogens causing foodborne gastroenteritis worldwide. Outer membrane vesicles (OMVs) are lipid-bilayer vesicles produced by Gram-negative bacteria, which contain biologically active components. We hypothesized that OMVs are an important weapon of S. enterica to initiate enteric diseases pathologies. In this study, the effects of S. enterica OMVs (SeOMVs) on intestinal microbiota and intestinal barrier function were investigated. In vitro fecal culture experiments showed that alpha diversity indexes and microbiota composition were altered by SeOMV supplementation. SeOMV supplementation showed an increase of pH, a decrease of OD630 and total short chain fatty acid (SCFA) concentrations. In vitro IPEC-J2 cells culture experiments showed that SeOMV supplementation did not affect the IPEC-J2 cell viability and the indicated genes expression. In vivo experiments in mice showed that SeOMVs had adverse effects on average daily gain (p < 0.05) and feed:gain ratio (p < 0.05), and had a tendency to decrease the final body weight (p = 0.073) in mice. SeOMV administration decreased serum interleukin-10 level (p < 0.05), decreased the relative abundance of bacteria belonging to the genera BacC-u-018 and Akkermansia (p < 0.05). Furthermore, SeOMV administration damaged the ileum mucosa (p < 0.05). These findings suggest that SeOMVs play an important role in the activation of intestinal inflammatory response induced by S. enterica, and downregulation of SCFA-producing bacteria is a possible mechanism.

Gut microbiota-based discovery of Houttuyniae Herba as a novel prebiotic of Bacteroides thetaiotaomicron with anti-colitis activity

Ulcerative colitis (UC) represents an inflammatory disease characterized by fluctuations in severity, posing substantial challenges in treatment. The gut microbiota plays a pivotal role in the pathogenesis of UC. This study sought to identify drugs specifically targeting the gut microbiota to mitigate UC. We initiated a meta-analysis on gut microbiota in UC patients to identify UC-associated bacterial strains. Subsequently, we screened 164 dietary herbal medicines in vitro to identify potential prebiotics for the UC-associated bacterium, Bacteroides thetaiotaomicron. The DSS-induced colitis mouse model was utilized to evaluate the anti-colitis efficacy of the identified dietary herbal medicine. Full-length 16 S rRNA amplicon sequencing was employed to observe changes in gut microbiota following dietary herbal medicine intervention. The relative abundance of Bacteroides was notably diminished in UC patients compared to their healthy counterparts. B. thetaiotaomicron exhibited an inverse relationship with UC symptoms, indicating its potential as an anti-colitis agent. In vitro assessments revealed that H. Herba significantly bolstered the proliferation of B. thetaiotaomicron. Further experiments showed that treating DSS-induced mice with an aqueous extract of H. Herba considerably alleviated colitis indicators such as weight loss, colon shortening, disease activity score (DAI), and systemic inflammation. Microbial analysis revealed B. thetaiotaomicron as the sole bacterium substantially augmented by H. Herba in vivo. Overall H. Herba emerges as a promising prebiotic for B. thetaiotaomicron, offering significant anti-colitis benefits. Employing a gut microbiota-centric approach proves valuable in the quest for drug discovery.This study provides a new paradigm for drug discovery that targets the gut microbiota to treat UC.

An altered expression of miR-376a-3p and miR-20a-5p in peripheral blood exosomes regulates the autophagy and inflammatory systemic substrates, and relates to the smoking habit and age in Crohn's disease

miRNAs are short single-stranded noncoding RNAs that participate as epigenetic regulators in inflammatory bowel disease. Most miRNAs detectable in serum are concentrated in exosomes, with relevant cargo for immunobiological processes. We set to evaluate the exosomes miRNAs content in the serum of patients with Crohn's disease (CD) and run a prospective observational study on CD patients on biological monotherapy and healthy controls. miRNA cargo was evaluated in peripheral blood-derived exosomes. Serum autophagy and inflammatory substrates were measured. Patients were followed for 6 months. Patients (n = 28) showed an overexpression of miR-376a-3p and a downregulation of miR-20a-5p compared to controls (n = 10), without significant differences between patients according to biologics. Serum autophagy substrates ATG4C (r = .57; p = .001) and ACRV1C (r = .66; p = .001) inversely correlated with miR-376a-3p expression, whereas IGF1R correlated with miR-20a-5p expression (r = .42; p = .02). Th1-related cytokines correlated with miR-376a-3p expression, whereas the Th17-associated cytokines inversely correlated with miR-20a-5p expression. Smoking (β = -2.301 CI 95% -3.790/-0.811, p = .004) remained as independent factor related to the overexpression of miR-376a-3p, whereas diagnosis before 16 years of age (β = 2.044 CI 95% 0.934/3.154, p = .001) and a younger age of patients (β = -.720 CI 95% -0.108/-0.035, p = .001) were related to decreased miR-20a-5p expression. Seven patients (25%) had a flare in the 6-month follow-up. Patients with overexpression of miR-376a-3p at the baseline showed an increased risk of flare during this period (OR 0.475 [0.237-0.950], p = .035). Finally, a comparative miRNA signature between biologic monotherapies was also explored. Targeting miR-376a-3p and miR-20a-5p epigenetic regulators may yield homeostatic effects on relevant biological processes related to disease progression in CD patients.

Therapeutic Applications of Extracellular Vesicles in Inflammatory Bowel Disease

The treatment landscape for inflammatory bowel disease (IBD) has undergone substantial advancements with the introduction of biologics. However, a considerable number of patients either show an immediate lack of response or lose responsiveness over time, necessitating the development of innovative and effective treatment approaches. Extracellular vesicles (EVs) are small lipid bilayer-enclosed structures that facilitate cell-to-cell molecular transfer and are integral to the pathogenesis of IBD. They play pivotal roles in maintaining the integrity of the intestinal epithelial barrier and the expulsion of cellular metabolites. The potential use of EVs as drug carriers or therapeutic agents has opened up a plethora of clinical applications. This review investigates the creation and content of EVs, their role in IBD development, and advances in their isolation and analytical techniques. Furthermore, the therapeutic promise they hold for IBD is explored, along with the latest research on their roles as IBD drug delivery systems.

Bacterial membrane vesicles in the pathogenesis and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and debilitating condition of relapsing and remitting inflammation in the gastrointestinal tract. Conventional therapeutic approaches for IBD have shown limited efficacy and detrimental side effects, leading to the quest for novel and effective treatment options for the disease. Bacterial membrane vesicles (MVs) are nanosized lipid particles secreted by lysis or blebbing processes from both Gram-negative and Gram-positive bacteria. These vesicles, known to carry bioactive components, are facsimiles of the parent bacterium and have been implicated in the onset and progression, as well as in the amelioration of IBD. This review discusses the overview of MVs and their impact in the pathogenesis, diagnosis, and treatment of IBD. We further discuss the technical challenges facing this research area and possible research questions addressing these challenges. We summarize recent advances in the diverse relationship between IBD and MVs, and the application of this knowledge as a viable and potent therapeutic strategy for IBD.

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.

Efficacy of extracellular vesicles as a cell-free therapy in colitis: a systematic review and meta-analysis of animal studies

Background: Extracellular vesicles (EVs) mediate inflammation, immune responses, gut barrier integrity, and intestinal homeostasis. Recently, the application of EVs in the treatment of inflammatory bowel disease (IBD) has been under intensive focus. Some studies have been conducted in animal models of colitis, while systematic reviews and meta-analyses are lacking. The current study aimed to conduct a systematic review and meta-analysis of studies investigating the efficacy of EVs on IBD. Methods: A systematic retrieval of all studies in PubMed, EMBASE, MEDLINE, Web of Science, and Cochrane Library reported the effects of EVs in the colitis model up to 22 June 2023. The methodological quality was assessed based on SYRCLE's risk of bias (RoB) tool. Disease activity index (DAI), myeloperoxidase activity (MPO), histopathological score (HS), and inflammatory cytokines (TNF-α, NF-κB, IL-1β, IL-6, and IL-10) were extracted as analysis indicators by Web Plot Digitizer 4.5. A meta-analysis was performed to calculate the standardized mean difference and 95% confidence interval using random-effect models by Review Manager 5.3 and STATA 14.0 software. Results: A total of 21 studies were included in this meta-analysis. Although the heterogeneity between studies and the potential publication bias limits confidence in the extent of the benefit, EV treatment was superior to the control in the colitis evaluation with reduced DAI, HS, MPO activity, and pro-inflammatory cytokines, including TNF-α, NF-κB, IL-1β, and IL-6, while increasing the content of anti-inflammatory cytokine IL-10 (all p < 0.05). Conclusion: Our meta-analysis results supported the protective effect of EVs on colitis rodent models based on their potential role in IBD therapy and propelling the field toward clinical studies.

Interactions between extracellular vesicles and microbiome in human diseases: New therapeutic opportunities

In recent decades, accumulating research on the interactions between microbiome homeostasis and host health has broadened new frontiers in delineating the molecular mechanisms of disease pathogenesis and developing novel therapeutic strategies. By transporting proteins, nucleic acids, lipids, and metabolites in their versatile bioactive molecules, extracellular vesicles (EVs), natural bioactive cell-secreted nanoparticles, may be key mediators of microbiota-host communications. In addition to their positive and negative roles in diverse physiological and pathological processes, there is considerable evidence to implicate EVs secreted by bacteria (bacterial EVs [BEVs]) in the onset and progression of various diseases, including gastrointestinal, respiratory, dermatological, neurological, and musculoskeletal diseases, as well as in cancer. Moreover, an increasing number of studies have explored BEV-based platforms to design novel biomedical diagnostic and therapeutic strategies. Hence, in this review, we highlight the recent advances in BEV biogenesis, composition, biofunctions, and their potential involvement in disease pathologies. Furthermore, we introduce the current and emerging clinical applications of BEVs in diagnostic analytics, vaccine design, and novel therapeutic development.

Extracellular vesicles from Lactobacillus druckerii inhibit hypertrophic scar fibrosis

BACKGROUND

Hypertrophic scars (HS) affect millions of people each year and require better treatment strategies. Bacterial extracellular vesicles (EVs) are advantaged by low cost and high yield which was commonly used in the treatment of diseases. Here, we investigated the therapeutic efficacy of EVs obtained from Lactobacillus druckerii in hypertrophic scar. In vitro, the effects of Lactobacillus druckerii-derived EVs (LDEVs) on Collagen I/III and α-SMA in fibroblasts obtained from HS. In vivo, a scleroderma mouse model was used to investigate the effects of LDEVs on fibrosis. The impact of LDEVs on excisional wound healing was explored. The different proteins between PBS and LDEVs treated fibroblasts derived from hypertrophic scar were studied by untargeted proteomic analysis.

RESULTS

In vitro, LDEVs treatment significantly inhibited the expression of Collagen I/III and α-SMA and cell proliferation of fibroblasts derived from HS. In vivo, LDEVs withdrawn the hypertrophic scar formation in scleroderma mouse model and decreased the expression of α-SMA. LDEVs promoted the proliferation of skin cells, new blood vessel formation and wound healing in excisional wound healing mice model. Moreover, proteomics has shown that LDEVs inhibit hypertrophic scar fibrosis through multiple pathways.

CONCLUSIONS

Our results indicated that Lactobacillus druckerii-derived EVs has the potential application in the treatment of hypertrophic scars and any other fibrosis diseases.

Extracellular Vesicles of Probiotics: Shedding Light on the Biological Activity and Future Applications

For many decades, the proper functioning of the human body has become a leading scientific topic. In the course of numerous experiments, a striking impact of probiotics on the human body has been documented, including maintaining the physiological balance of endogenous microorganisms, regulating the functioning of the immune system, enhancing the digestive properties of the host, and preventing or alleviating the course of many diseases. Recent research, especially from the last decade, shows that this health-benefiting activity of probiotics is largely conditioned by the production of extracellular vesicles. Although the importance of extracellular vesicles in the virulence of many live-threatening pathogens is widely described in the literature, much less is known with respect to the health-promoting effect of extracellular vesicles secreted by non-pathogenic microorganisms, including probiotics. Based on this, in the current review article, we decided to collect the latest literature data on the health-inducing properties of extracellular vesicles secreted by probiotics. The characteristics of probiotics' extracellular vesicles will be extended by the description of their physicochemical properties and the proteome in connection with the biological activities exhibited by these structures.

Potential of Gut Microbe-Derived Extracellular Vesicles to Differentiate Inflammatory Bowel Disease Patients from Healthy Controls

Background/Aims

This study aimed to evaluate the potential of the stool microbiome and gut microbe-derived extracellular vesicles (EVs) to differentiate between patients with inflammatory bowel disease (IBD) and healthy controls, and to predict relapse in patients with IBD.

Methods

Metagenomic profiling of the microbiome and bacterial EVs in stool samples of controls (n=110) and patients with IBD (n=110) was performed using 16S rRNA sequencing and then compared. Patients with IBD were divided into two enterotypes based on their microbiome, and the cumulative risk of relapse was evaluated.

Results

There was a significant difference in the composition of the stool microbiome and gut microbe-derived EVs between patients with IBD and controls. The alpha diversity of the microbiome in patients with IBD was significantly lower than that in controls, while the beta diversity also differed significantly between the two groups. These findings were more prominent in gut microbe-derived EVs than in the stool microbiome. The survival curve tended to be different for enterotypes based on the gut microbe-derived EVs; however, this difference was not statistically significant (log-rank test, p=0.166). In the multivariable analysis, elevated fecal calprotectin (>250 mg/kg) was the only significant risk factor associated with relapse (adjusted hazard ratio, 3.147; 95% confidence interval, 1.545 to 6.408; p=0.002).

Conclusions

Analysis of gut microbe-derived EVs is better at differentiating patients with IBD from healthy controls than stool microbiome analysis.

Extracellular Vesicles from Animal Milk: Great Potentialities and Critical Issues

Other than representing the main source of nutrition for newborn mammals, milk delivers a sophisticated signaling system from mother to child that promotes postnatal health. The bioactive components transferred through the milk intake are important for the development of the newborn immune system and include oligosaccharides, lactoferrin, lysozyme, α-La, and immunoglobulins. In the last 15 years, a pivotal role in this mother-to-child exchange has been attributed to extracellular vesicles (EVs). EVs are micro- and nanosized structures enclosed in a phospholipidic double-layer membrane that are produced by all cell types and released in the extracellular environment, reaching both close and distant cells. EVs mediate the intercellular cross-talk from the producing to the receiving cell through the transfer of molecules contained within them such as proteins, antigens, lipids, metabolites, RNAs, and DNA fragments. The complex cargo can induce a wide range of functional modulations in the recipient cell (i.e., anti-inflammatory, immunomodulating, angiogenetic, and pro-regenerative modulations) depending on the type of producing cells and the stimuli that these cells receive. EVs can be recovered from every biological fluid, including blood, urine, bronchoalveolar lavage fluid, saliva, bile, and milk, which is one of the most promising scalable vesicle sources. This review aimed to present the state-of-the-art of animal-milk-derived EV (mEV) studies due to the exponential growth of this field. A focus on the beneficial potentialities for human health and the issues of studying vesicles from milk, particularly for the analytical methodologies applied, is reported.

The synthesis of extracellular vesicles by the protistan parasite Blastocystis

Blastocystis is a genus of single-celled protist belonging to the stramenopile group. Prior studies have shown that isolates of Blastocystis subtype 7 (ST7) induced higher levels of intestinal epithelial cell damage and gut microbiota dysbiosis in comparison to other subtypes in in vivo and in vitro settings. Prior research has shown a link between gut dysbiosis and exposure to extracellular vesicles (EVs) produced by pathogenic microorganisms. This study demonstrates a protocol for the isolation of EVs from Blastocystis ST7 via ultracentrifugation. Nanoparticle tracking analysis and transmission electron microscopy were used to assess EV size and morphology. The protein content of isolated EVs was assessed by mass spectrophotometry and the presence of EV markers were evaluated by Western blotting. Finally, the EVs were cocultured with prominent human gut microbiome species to observe their effect on prokaryote growth. Our data shows that Blastocystis ST7 secretes EVs that are similar in morphology to previously characterized EVs from other organisms and that these EVs contain a limited yet unique protein cargo with functions in host-parasite intercellular communication and cell viability. This cargo may be involved in mediating the effects of Blastocystis on its surrounding environment.

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.

Extracellular Vesicles—Oral Therapeutics of the Future

Considered an artifact just after discovery, the possibility of oral delivery of extracellular vesicles (EVs) and their functional cargos has recently gained much research attention. EVs from various sources, including edible plants, milk, bacteria and mammalian cells, have emerged as a platform for miRNA and drug delivery that seem to induce the expected immune effects locally and in distant tissues after oral administration. Such a possibility greatly expands the clinical applicability of EVs. The present review summarizes research findings that either support or deny the biological/therapeutical activity of orally administered EVs and their role in cross-species and cross-kingdom signaling.

Messages from the Small Intestine Carried by Extracellular Vesicles in Prediabetes: A Proteomic Portrait

Extracellular vesicles (EVs) mediate communication in physiological and pathological conditions. In the pathogenesis of type 2 diabetes, inter-organ communication plays an important role in its progress and metabolic surgery leads to its remission. Moreover, gut dysbiosis is emerging as a diabetogenic factor. However, it remains unclear how the gut senses metabolic alterations and whether this is transmitted to other tissues via EVs. Using a diet-induced prediabetic mouse model, we observed that protein packaging in gut-derived EVs (GDE), specifically the small intestine, is altered in prediabetes. Proteins related to lipid metabolism and to oxidative stress management were more abundant in prediabetic GDE compared to healthy controls. On the other hand, proteins related to glycolytic activity, as well as those responsible for the degradation of polyubiquitinated composites, were depleted in prediabetic GDE. Together, our findings show that protein packaging in GDE is markedly modified during prediabetes pathogenesis, thus suggesting that prediabetic alterations in the small intestine are translated into modified GDE proteomes, which are dispersed into the circulation where they can interact with and influence the metabolic status of other tissues. This study highlights the importance of the small intestine as a tissue that propagates prediabetic metabolic dysfunction throughout the body and the importance of GDE as the messengers. Data are available via ProteomeXchange with identifier PXD028338.

Cow Milk Extracellular Vesicle Effects on an In Vitro Model of Intestinal Inflammation

Extracellular vesicles (EVs) are lipid bilayer nano-dimensional spherical structures and act mainly as signaling mediators between cells, in particular modulating immunity and inflammation. Milk-derived EVs (mEVs) can have immunomodulatory and anti-inflammatory effects, and milk is one of the most promising food sources of EVs. In this context, this study aimed to evaluate bovine mEVs anti-inflammatory and immunomodulating effects on an in vitro co-culture (Caco-2 and THP-1) model of intestinal inflammation through gene expression evaluation with RT-qPCR and cytokine release through ELISA. After establishing a pro-inflammatory environment due to IFN-γ and LPS stimuli, CXCL8, IL1B, TNFA, IL12A, IL23A, TGFB1, NOS2, and MMP9 were significantly up-regulated in inflamed Caco-2 compared to the basal co-culture. Moreover, IL-17, IL-1β, IL-6, TNF-α release was increased in supernatants of THP-1. The mEV administration partially restored initial conditions with an effective anti-inflammatory activity. Indeed, a decrease in gene expression and protein production of most of the tested cytokines was detected, together with a significant gene expression decrease in MMP9 and the up-regulation of MUC2 and TJP1. These results showed a fundamental capability of mEVs to modulate inflammation and their potential beneficial effect on the intestinal mucosa.

Commensal and Pathogenic Bacterial-Derived Extracellular Vesicles in Host-Bacterial and Interbacterial Dialogues: Two Sides of the Same Coin

Extracellular vesicles (EVs) cause effective changes in various domains of life. These bioactive structures are essential to the bidirectional organ communication. Recently, increasing research attention has been paid to EVs derived from commensal and pathogenic bacteria in their potential role to affect human disease risk for cancers and a variety of metabolic, gastrointestinal, psychiatric, and mental disorders. The present review presents an overview of both the protective and harmful roles of commensal and pathogenic bacteria-derived EVs in host-bacterial and interbacterial interactions. Bacterial EVs could impact upon human health by regulating microbiota–host crosstalk intestinal homeostasis, even in distal organs. The importance of vesicles derived from bacteria has been also evaluated regarding epigenetic modifications and applications. Generally, the evaluation of bacterial EVs is important towards finding efficient strategies for the prevention and treatment of various human diseases and maintaining metabolic homeostasis.

Extracellular vesicles produced by the human commensal gut bacterium Bacteroides thetaiotaomicron affect host immune pathways in a cell-type specific manner that are altered in inflammatory bowel disease

The gastrointestinal (GI) tract harbours a complex microbial community, which contributes to its homeostasis. A disrupted microbiome can cause GI-related diseases, including inflammatory bowel disease (IBD), therefore identifying host-microbe interactions is crucial for better understanding gut health. Bacterial extracellular vesicles (BEVs), released into the gut lumen, can cross the mucus layer and access underlying immune cells. To study BEV-host interactions, we examined the influence of BEVs generated by the gut commensal bacterium, Bacteroides thetaiotaomicron, on host immune cells. Single-cell RNA sequencing data and host-microbe protein-protein interaction networks were used to predict the effect of BEVs on dendritic cells, macrophages and monocytes focusing on the Toll-like receptor (TLR) pathway. We identified biological processes affected in each immune cell type and cell-type specific processes including myeloid cell differentiation. TLR pathway analysis highlighted that BEV targets differ among cells and between the same cells in healthy versus disease (ulcerative colitis) conditions. The in silico findings were validated in BEV-monocyte co-cultures demonstrating the requirement for TLR4 and Toll-interleukin-1 receptor domain-containing adaptor protein (TIRAP) in BEV-elicited NF-kB activation. This study demonstrates that both cell-type and health status influence BEV-host communication. The results and the pipeline could facilitate BEV-based therapies for the treatment of IBD.

An Update on the Role of Extracellular Vesicles in the Pathogenesis of Necrotizing Enterocolitis and Inflammatory Bowel Diseases

Some of the most fundamental influences of microorganisms inhabiting the human intestinal tract are exerted during infant development and impact the maturation of intestinal mucosa and gut immune system. The impact of bacteria on the host gut immune system is partially mediated via released extracellular vesicles (EVs). The heterogeneity in EV content, size, and bacterial species origin can have an impact on intestinal cells, resulting in inflammation and an immune response, or facilitate pathogen entry into the gut wall. In mammals, maintaining the integrity of the gut barrier might also be an evolutionary function of maternal milk EVs. Recently, the usage of EVs has been explored as a novel therapeutic approach in several pathological conditions, including necrotizing enterocolitis (NEC) and inflammatory bowel disease (IBD). In this review, we attempt to summarize the current knowledge of EV biology, followed by a discussion of the role that EVs play in gut maturation and the pathogenesis of NEC and IBD.

Bacterial membrane vesicle functions, laboratory methods, and applications

Bacterial membrane vesicles are cupped-shaped structures formed by bacteria in response to environmental stress, genetic alteration, antibiotic exposure, and others. Due to the structural similarities shared with the producer organism, they can retain certain characteristics like stimulating immune responses. They are also able to carry molecules for long distances, without changes in the concentration and integrity of the molecule. Bacteria originally secrete membrane vesicles for gene transfer, excretion, cell to cell interaction, pathogenesis, and protection against phages. These functions are unique and have several innovative applications in the pharmaceutical industry that have attracted both scientific and commercial interest.This led to the development of efficient methods to artificially stimulate vesicle production, purification, and manipulation in the lab at nanoscales. Also, for specific applications, engineering methods to impart pathogen antigens against specific diseases or customization as cargo vehicles to deliver payloads to specific cells have been reported. Many applications of bacteria membrane vesicles are in cancer drugs, vaccines, and adjuvant development with several candidates in clinical trials showing promising results. Despite this, applications in therapy and commercialization stay timid probably due to some challenges one of which is the poor understanding of biogenesis mechanisms. Nevertheless, so far, bacterial membrane vesicles seem to be a reliable and cost-efficient technology with several therapeutic applications. Research toward characterizing more membrane vesicles, genetic engineering, and nanotechnology will enable the scope of applications to widen. This might include solutions to other currently faced medical and healthcare-related challenges.

Bacterial Extracellular Vesicles in Gastrointestinal Tract Cancer: An Unexplored Territory

Bacterial extracellular vesicles are membrane-enclosed, lipid bi-layer nanostructures that carry different classes of biomolecules, such as nucleic acids, lipids, proteins, and diverse types of small molecular metabolites, as their cargo. Almost all of the bacteria in the gut secrete extracellular vesicles to assist them in competition, survival, material exchange, host immune modulation, infection, and invasion. The role of gut microbiota in the development, progression, and pathogenesis of gastrointestinal tract (GIT) cancer has been well documented. However, the possible involvement of bacterial extracellular vesicles (bEVs) in GIT cancer pathophysiology has not been given due attention. Studies have illustrated the ability of bEVs to cross physiological barriers, selectively accumulate near tumor cells, and possibly alter the tumor microenvironment (TME). A systematic search of original published works related to bacterial extracellular vesicles on gastrointestinal cancer was performed for this review. The current systemic review outlines the possible impact of gut microbiota derived bEVs in GIT cancer in light of present-day understanding. The necessity of using advanced sequencing technologies, such as genetic, proteomic, and metabolomic investigation methodologies, to facilitate an understanding of the interrelationship between cancer-associated bacterial vesicles and gastrointestinal cancer is also emphasized. We further discuss the clinical and pharmaceutical potential of bEVs, along with future efforts needed to understand the mechanism of interaction of bEVs in GIT cancer pathogenesis.

Metagenomic Profiling of Fecal-Derived Bacterial Membrane Vesicles in Crohn's Disease Patients

BACKGROUND

In the past, many studies suggested a crucial role for dysbiosis of the gut microbiota in the etiology of Crohn's disease (CD). However, despite being important players in host-bacteria interaction, the role of bacterial membrane vesicles (MV) has been largely overlooked in the pathogenesis of CD. In this study, we addressed the composition of the bacterial and MV composition in fecal samples of CD patients and compared this to the composition in healthy individuals.

METHODS

Fecal samples from six healthy subjects (HC) in addition to twelve CD patients (six active, six remission) were analyzed in this study. Fecal bacterial membrane vesicles (fMVs) were isolated by a combination of ultrafiltration and size exclusion chromatography. DNA was obtained from the fMV fraction, the pellet of dissolved feces as bacterial DNA (bDNA), or directly from feces as fecal DNA (fDNA). The fMVs were characterized by nanoparticle tracking analysis and cryo-electron microscopy. Amplicon sequencing of 16s rRNA V4 hypervariable gene regions was conducted to assess microbial composition of all fractions.

RESULTS

Beta-diversity analysis showed that the microbial community structure of the fMVs was significantly different from the microbial profiles of the fDNA and bDNA. However, no differences were observed in microbial composition between fDNA and bDNA. The microbial richness of fMVs was significantly decreased in CD patients compared to HC, and even lower in active patients. Profiling of fDNA and bDNA demonstrated that Firmicutes was the most dominant phylum in these fractions, while in fMVs Bacteroidetes was dominant. In fMV, several families and genera belonging to Firmicutes and Proteobacteria were significantly altered in CD patients when compared to HC.

CONCLUSION

The microbial alterations of MVs in CD patients particularly in Firmicutes and Proteobacteria suggest a possible role of MVs in host-microbe symbiosis and induction or progression of inflammation in CD pathogenesis. Yet, the exact role for these fMV in the pathogenesis of the disease needs to be elucidated in future studies.

Drug delivery to the inflamed intestinal mucosa - targeting technologies and human cell culture models for better therapies of IBD

Current treatment strategies for inflammatory bowel disease (IBD) seek to alleviate the undesirable symptoms of the disorder. Despite the higher specificity of newer generation therapeutics, e.g. monoclonal antibodies, adverse effects still arise from their interference with non-specific systemic immune cascades. To circumvent such undesirable effects, both conventional and newer therapeutic options can benefit from various targeting strategies. Of course, both the development and the assessment of the efficiency of such targeted delivery systems necessitate the use of suitable in vivo and in vitro models representing relevant pathophysiological manifestations of the disorder. Accordingly, the current review seeks to provide a comprehensive discussion of the available preclinical models with emphasis on human in vitro models of IBD, along with their potentials and limitations. This is followed by an elaboration on the advancements in the field of biology- and nanotechnology-based targeted drug delivery systems and the potential rooms for improvement to facilitate their clinical translation.

Extracellular vesicles-mediated interaction within intestinal microenvironment in inflammatory bowel disease

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EVs derived from different sources play modulatory functions in the intestine, especially interaction associated with microbiota.

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An EV-mediated interaction system was established to describe the possible mechanism of IBD pathogenesis and its cure.

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EVs-based treatments show great potential of clinical applications in IBD diagnosis and therapy.

Background

The intestinal tract is a complicated ecosystem with dynamic homeostasis via interaction of intestine and microbiota. Inflammatory bowel disease (IBD) is chronic intestinal inflammation involving dysbiosis of intestinal microenvironment. Extracellular vesicles (EVs), as vital characteristics of cell–cell and cell-organism communication, contribute to homeostasis in intestine. Recently, EVs showed excellent potential for clinical applications in disease diagnoses and therapies.

Aim of Review

Our current review discusses the modulatory functions of EVs derived from different sources in intestine, especially their effects and applications in IBD clinical therapy. EV-mediated interaction systems between host intestine and microbiota were established to describe possible mechanisms of IBD pathogenesis and its cure.

Key Scientific Concepts of Review

EVs are excellent vehicles for delivering molecules containing genetic information to recipient cells. Multiple pieces of evidence have illustrated that EVs participate the interaction between host and microbiota in intestinal microenvironment. In inflammatory intestine with dysbiosis of microbiota, EVs as regulators target promoting immune response and microbial reconstruction. EVs-based immunotherapy could be a promising therapeutic approach for the treatment of IBD in the near future.

Serum Exosomes Derived from Irritable Bowel Syndrome Patient Increase Cell Permeability via Regulating miR-148b-5p/RGS2 Signaling in Human Colonic Epithelium Cells

Aim

Irritable bowel syndrome (IBS) is a multifactorial functional bowel disorder characterized by disruption of the intestinal barrier. Circulating exosomal microRNAs (miRNAs) are involved in regulating epithelial barrier function, and upregulation of miR-148b-5p has been detected in IBS. However, whether exosomal miR-148-5p is involved in the IBS pathogenesis remains unclear. This study was aimed at investigating the relationship of exosomal miR-148-5p with colonic epithelial permeability.

Methods

Exosomes were isolated from the serum of IBS patients and healthy controls. HT-29 cells were cultured with the IBS-derived serum exosomes (IBS-exo). Exosome uptake assay was used to evaluate whether the IBS-exo could be absorbed by HT-29 cells. FITC-Dextran flux and transepithelial/endothelial electrical resistance were measured to evaluate epithelial permeability. A luciferase reporter assay was used to determine whether the regulator of G protein signaling- (RGS-) 2 is a target gene of miR-148b-5p.

Results

miR-148b-5p was obviously elevated in the IBS-exo compared to the control-exo. Upregulation of miR-148b-5p was observed in the HT-29 cells cultured with IBS-exo. Exposure to IBS-exo increased cell permeability and decreased RGS2 expression. The IBS-exo-induced alterations were obviously reversed by interfering with the miR-148b-5p expression. Mimicking the IBS-exo treatment, miR-148b-5p overexpression increased cell permeability and downregulated RGS2 expression, which were abrogated by overexpressing RGS2. The luciferase reporter assay revealed that RGS2 was a direct target of miR-148b-5p.

Conclusions

Serum-derived exosomes from IBS patients increase colonic epithelial permeability via miR-148b-5p/RGS2 signaling.

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.

Restoration of dysbiotic human gut microbiome for homeostasis

The human microbiome is a complex and dynamic ecosystem, and the imbalance of its microbial community structure from the normal state is termed dysbiosis. The dysbiotic gut microbiome has been proved to be related to several pathological conditions like Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS), Colorectal Cancer (CRC), etc., and several other extra-intestinal conditions like Type 1 & 2 diabetes, obesity, etc. The complex gut microbial ecosystem starts to build before the birth of an individual. It is known to get affected by several factors such as birth mode, individual lifestyle, dietary practices, medications, and antibiotics. A dysbiotic microbiome can potentially hamper host homeostasis due to its role in immune modulation, metabolism, nutrient synthesis, etc. Restoration of the dysbiotic gut microbiome has emerged as a promising aid and a better therapeutic approach. Several approaches have been investigated to achieve this goal, including prebiotics and probiotics, Fecal Microbiota Transplantation (FMT), extracellular vesicles, immune modulation, microbial metabolites, dietary interventions, and phages. This review discusses the various factors that influence the human microbiome with respect to their cause-effect relationship and the effect of gut microbiome compositional changes on the brain through the gut-brain axis. We also discuss the practices used globally for gut microbiome restoration purposes, along with their effectiveness.

Microbiota-host communications: Bacterial extracellular vesicles as a common language

Both gram-negative and gram-positive bacteria release extracellular vesicles (EVs) that contain components from their mother cells. Bacterial EVs are similar in size to mammalian-derived EVs and are thought to mediate bacteria–host communications by transporting diverse bioactive molecules including proteins, nucleic acids, lipids, and metabolites. Bacterial EVs have been implicated in bacteria–bacteria and bacteria–host interactions, promoting health or causing various pathologies. Although the science of bacterial EVs is less developed than that of eukaryotic EVs, the number of studies on bacterial EVs is continuously increasing. This review highlights the current state of knowledge in the rapidly evolving field of bacterial EV science, focusing on their discovery, isolation, biogenesis, and more specifically on their role in microbiota–host communications. Knowledge of these mechanisms may be translated into new therapeutics and diagnostics based on bacterial EVs.

The roles of parasite-derived extracellular vesicles in disease and host-parasite communication

In recent years, several parasites have been shown to interact with their hosts through intra- and inter-community communication mechanisms, which were identified to be mediated by extracellular vesicles (EVs) through various uptake mechanisms. EVs are a heterogenous group of nanoparticles (~30-5000 nm) classified into three main types according to their size and biogenesis. EVs contain proteins, lipids, nucleic acids and metabolites from the cell of origin which are essential for genetic exchange, biomarker identification and diagnosis of pathological diseases. As important "forward lines of parasite infectivity", the parasite-secreted EVs function as information transmitters in the early-stage of host-parasite interaction and subsequent host-cell colonization. For this review, we summarize from the literature the relevance of EVs to the pathogenesis and development of human parasitic protistan diseases such as giardiasis, leishmaniasis, amoebiasis, malaria and Blastocystis-mediated gut pathology. Specific in vitro and in vivo interactions of the parasite-EVs and the host, with the reported cellular and immunological outcomes are discussed in this review. EVs have great potential to be further developed as diagnostic, immunomodulation and therapeutic alternatives to fill the knowledge gaps in the current parasitic diseases discussed in this review. Nanomedicine and vaccine development could be explored, with the utilization and/or modification of the parasitic EVs as novel treatment and prevention strategies.

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.

Microbiota-derived extracellular vesicles and metabolic syndrome

AIM

Metabolic syndrome is a major health problem concerning approximately 25% of worldwide population. Metabolic syndrome regroups a cluster of five metabolic abnormalities predisposing to Type 2 Diabetes mellitus. Dysbiotic gut microbiota is accompanied by an increase of both intestinal permeability and pathogen-associated molecular patterns translocation into blood circulation to induce metabolic endotoxemia responsible for the low-grade systemic inflammation and insulin resistance in metabolic syndrome. Among pathogen-associated molecular patterns, bacterial extracellular vesicles are gaining growing attention. The latter are produced by eukaryotic and prokaryotic cells and are vectors of communication between gut microbiota and its host The present review brings evidence to the importance of the control of the balance between the different subsets of gut microbiota in the development of metabolic diseases including metabolic syndrome.

RESULTS

The ability of bacteria, including gut bacteria, to release extracellular vesicles implicated in host metabolic homeostasis is highlighted with their plethora of actions on intestinal barrier, inflammation and insulin resistance.

CONCLUSION

Bacterial extracellular vesicles can be considered as key players in the pathophysiological of metabolic diseases and may represent an interesting strategy for specific manipulations of microbiome for promoting host health.

Extracellular Vesicles in Inflammatory Bowel Disease: Small Particles, Big Players

Extracellular vesicles are nanovesicles released by many cell types into the extracellular space. They are important mediators of intercellular communication, enabling the functional transfer of molecules from one cell to another. Moreover, their molecular composition reflects the physiological status of the producing cell and tissue. Consequently, these vesicles have been involved in many [patho]physiological processes such as immunomodulation and intestinal epithelial repair, both key processes involved in inflammatory bowel disease. Given that these vesicles are present in many body fluids, they also provide opportunities for diagnostic, prognostic, and therapeutic applications. In this review, we summarise functional roles of extracellular vesicles in health and disease, with a focus on immune regulation and intestinal barrier integrity, and review recent studies on extracellular vesicles and inflammatory bowel disease. We also elaborate on their clinical potential in inflammatory bowel disease.

Role and mechanisms of exosomal miRNAs in IBD pathophysiology

Exosomes represent secretory membranous vesicles used for the information exchange between cells and organ-to-organ communication. Exosome crosstalk mechanisms are involved in the regulation of several inflammatory bowel disease (IBD)-associated pathophysiological intestinal processes such as barrier function, immune responses, and intestinal flora. Functional biomolecules, mainly noncoding RNAs (ncRNAs), are believed to be transmitted between the mammalian cells via exosomes that likely play important roles in cell-to-cell communication, both locally and systemically. MicroRNAs (miRNAs) encapsulated in exosomes have generated substantial interest because of their critical roles in multiple pathophysiological processes. In addition, exosomal miRNAs are implicated in the gut health. MiRNAs are selectively and actively loaded into the exosomes and then transferred to the target recipient cell where they manipulate cell function through posttranscriptional silencing of target genes. Intriguingly, miRNA profile of exosomes differs from their cellular counterparts suggesting an active sorting and packaging mechanism of exosomal miRNAs. Even more exciting is the involvement of posttranscriptional modifications in the specific loading of miRNAs into exosomes, but the underlying mechanisms of how these modifications direct ncRNA sorting have not been established. This review gives a brief overview of the status of exosomes and exosomal miRNAs in IBD and also discusses potential mechanisms of exosomal miRNA sorting and delivering.

Mycobacterial Hsp65 antigen delivered by invasive Lactococcus lactis reduces intestinal inflammation and fibrosis in TNBS-induced chronic colitis model

Intestinal fibrosis associated with Crohn's disease (CD), which a common and serious complication of inflammatory bowel diseases. In this context, heat shock proteins (HSPs) might serve as an alternative treatment because these antigens play important roles in the regulation of effector T cells. We thus evaluated the anti-inflammatory and antifibrotic capacities of an invasive and Hsp65-producing strain-Lactococcus lactis NCDO2118 FnBPA+ (pXYCYT:Hsp65)-in chronic intestinal inflammation to assess its potential as an alternative therapeutic strategy against fibrotic CD. Experimental colitis was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in BALB/c mice, and the mice were treated orally with L. lactis NCDO2118 FnBPA+ (pXYCYT:Hsp65) via intragastric gavage. The oral administration of this strain significantly attenuated the severity of inflammation and intestinal fibrosis in mice (p < 0.05). These results are mainly justified by reductions in the levels of the pro-fibrotic cytokines IL-13 and TGF-β and increases in the concentration of the regulatory cytokine IL-10. The L. lactis NCDO2118 FnBPA+ (pXYCYT:Hsp65) strain contributed to reductions in the severity of inflammatory damage in chronic experimental CD, and these findings confirm the effectiveness of this new antifibrotic strategy based on the delivery of therapeutic proteins to inside cells of the host intestinal mucosa.

Synbiotic supplementation containing Bifidobacterium infantis and xylooligosaccharides alleviates dextran sulfate sodium-induced ulcerative colitis

Synbiotics (Bifidobacterium infantis + xylooligosaccharides) had the strongest efficacy on colitis through inhibiting inflammation and oxidative stress and protecting epithelial integrity.