Helicobacter pylori-derived outer membrane vesicles suppress liver autophagy: A novel mechanism for H. pylori-mediated hepatic disorder

The effect of Helicobacter pylori-derived extracellular vesicles on glucose metabolism and induction of insulin resistance in HepG2 cells

Helicobacter pylori infection has been associated with the development of insulin resistance (IR). This study aimed to examine the effect of H. pylori-derived extracellular vesicles (EVs) on IR induction. EVs were derived from two H. pylori strains, and characterised by transmission electron microscopy and dynamic light scattering. Different concentrations of insulin were added to HepG2 cells to induce IR model. HepG2 cells were exposed to various concentrations of H. pylori-derived EVs to assess IR development. The gene expression of IRS1, AKT2, GLUT2, IL-6, SOCS3, c-Jun and miR-140 was examined using RT-qPCR. Glucose uptake analysis revealed insulin at 5 × 10 -7 mol/l and EVs at 50 µg/ml induced IR model in HepG2 cells. H. pylori-derived EVs downregulated the expression level of IRS1, AKT2, and GLUT2, and upregulated IL-6, SOCS3, c-Jun, and miR-140 expression in HepG2 cells. In conclusion, our findings propose a novel mechanism by which H. pylori-derived EVs could potentially induce IR.

The role and mechanisms of Helicobacter pylori outer membrane vesicles in the pathogenesis of extra-gastrointestinal diseases

Helicobacter pylori (H. pylori) infection have been closely associated with several extra-gastrointestinal disorders. Outer membrane vesicles (OMVs), as lipid-membrane-bounded nanoparticles, are usually shed from Gram-negative both in vitro and in vivo. H. pylori is also capable of producing OMVs, which can enter the systemic circulation and be delivered to various cells, tissues or organs, eliciting a range of inflammatory and immune modulation responses. In this current review, we summarize the biogenesis and functions of H. pylori OMVs, describe the contribution of H. pylori OMVs to the generation and progression of extra-gastrointestinal diseases, such as neuronal damage, Alzheimer disease, hepatic fibrosis and atherosclerosis. We also explored the effect of H. pylori OMVs in inflammatory and immune modulation of diverse immune cells, including macrophages, mononuclear cells and dendritic cells. By elucidating the molecular mechanism of H. pylori OMVs-mediated extra-gastrointestinal diseases and immunomodulatory effect, it may promote the development of efficient treatments and vaccinations against H. pylori.

Extracellular vesicles in Helicobacter pylori-mediated diseases: mechanisms and therapeutic potential

Extracellular vesicles (EVs) are relevant elements for cell-to-cell communication and are considered crucial in host-pathogen interactions by transferring molecules between the pathogen and the host during infections. These structures participate in various physiological and pathological processes and are considered promising candidates as disease markers, therapeutic reagents, and drug carriers. Both H. pylori and the host epithelial cells infected by H. pylori secrete EVs, which contribute to inflammation and the development of disease phenotypes. However, many aspects of the cellular and molecular biology of EV functions remain incompletely understood due to methodological challenges in studying these small structures. This review also highlights the roles of EVs derived from H. pylori-infected cells in the pathogenesis of gastric and extragastric diseases. Understanding the specific functions of these EVs during H. pylori infections, whether are advantageous to the host or the pathogen, may help the development new therapeutic approaches to prevent disease.

Review on bacterial outer membrane vesicles: structure, vesicle formation, separation and biotechnological applications

Outer membrane vesicles (OMVs), shed by Gram-negative bacteria, are spherical nanostructures that play a pivotal role in bacterial communication and host-pathogen interactions. Comprising an outer membrane envelope and encapsulating a variety of bioactive molecules from their progenitor bacteria, OMVs facilitate material and informational exchange. This review delves into the recent advancements in OMV research, providing a comprehensive overview of their structure, biogenesis, and mechanisms of vesicle formation. It also explores their role in pathogenicity and the techniques for their enrichment and isolation. Furthermore, the review highlights the burgeoning applications of OMVs in the field of biomedicine, emphasizing their potential as diagnostic tools, vaccine candidates, and drug delivery vectors.

Helicobacter pylori outer membrane vesicles and infected cell exosomes: new players in host immune modulation and pathogenesis

Outer membrane vesicles (OMVs) and exosomes are essential mediators of host-pathogen interactions. Elucidating their mechanisms of action offers valuable insights into diagnosing and treating infectious diseases and cancers. However, the specific interactions of Helicobacter pylori (H. pylori) with host cells via OMVs and exosomes in modulating host immune responses have not been thoroughly investigated. This review explores how these vesicles elicit inflammatory and immunosuppressive responses in the host environment, facilitate pathogen invasion of host cells, and enable evasion of host defenses, thereby contributing to the progression of gastric diseases and extra-gastric diseases disseminated through the bloodstream. Furthermore, the review discusses the challenges and future directions for investigating OMVs and exosomes, underscoring their potential as therapeutic targets in H. pylori-associated diseases.

Anticancer Effects of Escherichia Coli-Derived Outer Membrane Vesicles Against Colorectal Cancer

Background

One of the deadliest cancers in the world, colorectal cancer has a dismal prognosis and a poor response to therapy. It was suggested that outer membrane vesicles (OMVs) produced by Escherichia coli (E. coli) are a powerful inducer of inflammation in intestinal epithelial cells. This research aimed to determine the anticancer potential of E. coli-derived OMVs using a colorectal cancer model.

Methods

Five distinct E. coli strains were collected for this study. Their OMVs were then isolated and characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The effects of E. coli-derived OMVs on colorectal cancer were evaluated in vitro and in vivo using a colorectal tumor model in nude mice.

Results

Obtained results showed that E. coli probiotic strains released spherical-shaped vesicles ranging from 5 to 200 nm. E. coli-derived OMVs showed that in the untreated group, a large portion of the tumor tissue continued to grow, with only a few cells undergoing apoptosis. Conversely, the OMV-treated group exhibited a higher number of apoptotic cells, highlighting the anticancer effects of E. coli-derived OMVs in colorectal cancer.

Conclusions

These results demonstrated that E. coli-derived OMVs can be employed as a potential treatment for colorectal cancer with minimal adverse effects. Mechanistic studies indicate that these vesicles may promote apoptosis and inhibit cell proliferation, supporting their therapeutic potential.

Effects of bacterial extracellular vesicles derived from oral and gastrointestinal pathogens on systemic diseases

Oral microbiota and gastrointestinal microbiota, the two largest microbiomes in the human body, are closely correlated and frequently interact through the oral-gut axis. Recent research has focused on the roles of these microbiomes in human health and diseases. Under normal conditions, probiotics and commensal bacteria can positively impact health. However, altered physiological states may induce dysbiosis, increasing the risk of pathogen colonization. Studies suggest that oral and gastrointestinal pathogens contribute not only to localized diseases at their respective colonized sites but also to the progression of systemic diseases. However, the mechanisms by which bacteria at these local sites are involved in systemic diseases remain elusive. In response to this gap, the focus has shifted to bacterial extracellular vesicles (BEVs), which act as mediators of communication between the microbiota and the host. Numerous studies have reported the targeted delivery of bacterial pathogenic substances from the oral cavity and the gastrointestinal tract to distant organs via BEVs. These pathogenic components subsequently elicit specific cellular responses in target organs, thereby mediating the progression of systemic diseases. This review aims to elucidate the extensive microbial communication via the oral-gut axis, summarize the types and biogenesis mechanisms of BEVs, and highlight the translocation pathways of oral and gastrointestinal BEVs in vivo, as well as the impacts of pathogens-derived BEVs on systemic diseases.

The modulatory effect of Lactobacillus gasseri ATCC 33323 on autophagy induced by extracellular vesicles of Helicobacter pylori in gastric epithelial cells in vitro

Helicobacter pylori has been recognized as a true pathogen, which is associated with various gastroduodenal diseases, and gastric adenocarcinoma. The crosstalk between H. pylori virulence factors and host autophagy remains challenging. H. pylori can produce extracellular vesicles (EVs) that contribute to gastric inflammation and malignancy. Some probiotic strains have been documented to modulate cell autophagy process. This study was aimed to investigate the modulatory effect of cell-free supernatant (CFS) obtained from Lactobacillus gasseri ATCC 33323 on autophagy induced by H. pylori-derived EVs. EVs were isolated from two clinical H. pylori strains (BY-1 and OC824), and characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The viability of AGS cells was assessed after exposure to different concentrations of H. pylori EVs, and L. gasseri CFS. Based on MTT assay and Annexin V-FITC/PI staining, 50 μg/ml of H. pylori EVs and 10 % v/v of L. gasseri CFS were used for further cell treatment experiments. Autophagy was examined using acridin orange (AO) staining, RT-qPCR analysis for autophagy mediators (LC3B, ATG5, ATG12, ATG16L1, BECN1, MTOR, and NOD1), and western blotting for LC3B expression. H. pylori EVs were detected to range in size from 50 to 200 nm. EVs of both H. pylori strains and L. gasseri CFS showed no significant effect on cell viability as compared to untreated cells. H. pylori EVs promoted the development of acidic vesicular organelles and the expression of autophagy-related genes (LC3B, ATG5, ATG12, ATG16L1, BECN1, and NOD1), and decreased the expression of MTOR in AGS cells at 12 and 24 h time periods. In addition, the production of LC3B was increased following 12 h of treatment in AGS cells. In contrast, L. gasseri CFS effectively inhibited EVs-induced autophagy, as evidenced by reduced acidic vesicular organelle formation and modulation of autophagy markers. Our study indicated that L. gasseri CFS can effectively suppress H. pylori EV-induced autophagy in AGS cells. Further investigations are required to decipher the mechanism of action L. gasseri CFS and its metabolites on autophagy inhibition induced by H. pylori.

Potential of the Novel Slot Blot Method with a PVDF Membrane for Protein Identification and Quantification in Kampo Medicines

Kampo is a Japanese traditional medicine modified from traditional Chinese medicine. Kampo medicines contain various traditional crude drugs with unknown compositions due to the presence of low-molecular-weight compounds and proteins. However, the proteins are generally rare and extracted with high-polarity solvents such as water, making their identification and quantification difficult. To develop methods for identifying and quantifying the proteins in Kampo medicines, in the current study we employ previous technology (e.g., column chromatography, electrophoresis, and membrane chromatography), focusing on membrane chromatography with a polyvinylidene difluoride (PVDF) membrane. Moreover, we consider slot blot analysis based on the principle of membrane chromatography, which is beneficial for analyzing the proteins in Kampo medicines as the volume of the samples is not limited. In this article, we assess a novel slot blot method developed in 2017 and using a PVDF membrane and special lysis buffer to quantify advanced glycation end products-modified proteins against other slot blots. We consider our slot blot analysis superior for identifying and quantifying proteins in Kampo medicines compared with other methods as the data obtained with our novel slot blot can be shown with both error bars and the statistically significant difference, and our operation step is simpler than those of other methods.