Project description:Numerous studies are devoted to the intestinal microbiota and intercellular communication maintaining homeostasis. In this regard, vesicles secreted by bacteria represent one of the most popular topics for research. For example, the outer membrane vesicles (OMVs) of Bacteroides fragilis play an important nutritional role with respect to other microorganisms and promote anti-inflammatory effects on immune cells. However, toxigenic B. fragilis (ETBF) contributes to bowel disease, even causing colon cancer. If nontoxigenic B. fragilis (NTBF) vesicles exert a beneficial effect on the intestine, it is likely that ETBF vesicles can be utilized for potential pathogenic implementation. To confirm this possibility, we performed comparative proteomic HPLC-MS/MS analysis of vesicles isolated from ETBF and NTBF. Furthermore, we performed, for the first time, HPLC-MS/MS and GS-MS comparative metabolomic analysis for the vesicles isolated from both strains with subsequent reconstruction of the vesicle metabolic pathways. We utilized fluxomic experiments to validate the reconstructed biochemical reaction activities and finally observed considerable difference in the vesicle proteome and metabolome profiles. Compared with NTBF OMVs, metabolic activity of ETBF OMVs provides their similarity to micro reactors that are likely to be used for long-term persistence and implementing pathogenic potential in the host.
Project description:Number of publications show that intestinal microflora vesicles secretion is essential for the maintaining homeostasis. Conducted comprehensive genomic, transcriptomic and proteomic studies of vesicles determine the nature and the basic mechanisms of bacterial influence to the host. The role of the vesicles to a greater extent is defined as carriers of virulence factors or enzymes determining the nutritional function. In addition some bacterial vesicles have a special mission. B.fragilis vesicles are providing anti-inflammatory effect on the colon immune cells. However there is no information about possible role of vesicles secreted by ETBF, contributing bowel disease development and colon cancer. To determine possible effects of ETBF vesicles to the host compared with NTBF, we performed comprehensive proteome and for the first time metabolome analysis and reconstructed pathways for vesicles of both strains with subsequent confirmation of the activity of one of the main pathway by fluxome analysis. A detailed analysis of the vesicles allowed us to discover a new quality of ETBF vesicles as intelligent systems capable of absorbing and processing of exogenous substrates. We believe that this property allows them to maintain stability for a long time and implement mechanisms of pathogenicity.
Project description:Characterization of the sRNA content of P. aeruginosa OMVs compared to whole cells. Result: OMVs contain differentially packaged sRNAs. Whole cell PA14 and OMVs from 3 separate preparations.
Project description:Helicobacter pylori, a bacterium that colonizes the human stomach, like all Gram-negative bacteria spontaneously shed outer membrane vesicles (OMVs). OMVs, which act as a delivery system for bacterial components, are involved in bacterial-host interactions and thus contribute to pathogenesis. In this study, to understand the gene expression changes that human gastric epithelial cells might undergo when exposed to H. pylori-OMVs, we profiled the transcriptomic changes of the MKN74 gastric cell line induced by OMVs compared to control cells and H. pylori-infected cells, using the Ion AmpliSeq™ Transcriptome Human Gene Expression Panel. The top enriched pathways in the OMVs challenge condition included amino acid-related metabolic pathways, mitogen-activated protein kinase signaling, autophagy, and ferroptosis. The cell cycle, DNA replication, and repair pathways were the top diminished pathways. The transcriptomic changes induced by OMVs were largely consistent with those of the bacteria, although often at low expression levels, suggesting that their effects will mostly reinforce those of the bacterium itself. Our data provide a valuable portrayal of the transcriptomic remodeling of gastric cells by H. pylori-OMVs, which can be further dissected regarding the underlying molecular mediators and explored to understand the pathobiology of the full-spectrum of H. pylori-mediated diseases.
Project description:Characterization of the sRNA content of P. aeruginosa OMVs compared to whole cells. Result: OMVs contain differentially packaged sRNAs.
Project description:Asthma is the most common chronic respiratory disease. Asthma that cannot be well controlled by steroid treatment is called steroid-resistant asthma. Steroid-resistant asthma accounts for only 5% of all asthma cases, but it accounts for 80% of asthma healthcare costs. Nontypeable Haemophilus influenzae (NTHi), as a Gram-negative bacterium, can release outer membrane vesicles (OMVs) and transfer biomolecules to host cells and the external environment by carrying lipopolysaccharides, proteins, peptidoglycans, outer membrane proteins, cell wall components, proteins, nucleic acids, ion metabolites, and signaling molecules. Thus, it plays a role in obtaining nutrition, stress, toxin delivery, adhesion, host immune surveillance evasion, and host immune response regulation. It becomes an essential way in bacterial pathogenesis. To further clarify whether NTHi OMVs could be inhaled to induce steroid-resistant asthma, we isolated and purified NTHi OMVs. In vivo experiments showed that NTHi OMVs could be inhaled and enter airway epithelial cells. Cosensitization with OVA induces steroid-resistant asthma in mice. Furthermore, through high-throughput sequencing, we found that the NTHi OMVs and OVA co-sensitized mice had significantly enriched inflammatory and immune-related signaling pathways, and the transcription and secretion of IL-1β were increased was the potential cause of SRA.
Project description:We performed comparative transcriptomic analysis of the outer membrane vesicles (OMVs) released from B. burgdorferi. We identified a total of ~1200 unique transcripts with at least one mapped read from the bacterial cell and its OMVs.
Project description:The outer membrane vesicles (OMVs) produced by Porphyromonas gingivalis (P. gingivalis) contain a variety of bioactive molecules that may be involved in the progression of periodontitis. However, the participation of P. gingivalis OMVs in the development of periodontitis has not been elucidated. Here we isolated P. gingivalis OMVs and confirmed their participation in periodontitis both in vivo and in vitro. Microcomputed Tomography (micro-CT) and histological analysis showed that under the stimulation of P. gingivalis OMVs, the alveolar bone of rats was significantly resorbed in vivo. We found that P. gingivalis OMVs were taken up by hPDLCs (human Periodontal Ligament Cells, hPDLCs) in vitro, then subsequently resulting in apoptosis and inflammatory cytokines releasing which was accomplished by the microRNA-size small RNAs (msRNAs) sRNA45033 in the P. gingivalis OMVs. Through bioinformatics analysis and screening of target genes, Chromobox 5 (CBX5) was identified as the downstream target of screened-out small RNA s45033. Using dual-luciferase reporter assay, overexpression, and knockdown methods, s45033 was confirmed to target CBX5 to regulate hPDLCs apoptosis. In addition, Cleavage Under Targets and Tagmentation (Cut&Tag) analysis confirmed the mechanism that CBX5 regulates apoptosis through the methylation of p53 DNA. Collectively, these findings indicate that the role of P. gingivalis OMVs is immunologically relevant and related to bacterial virulence in the development of periodontitis.
Project description:Outer-inner membrane vesicles (O-IMVs) were recently described as a new type of membrane vesicle secreted by the Antarctic bacterium Shewanella vesiculosa M7T. Their formation is characterized by the protrusion of both outer and plasma membranes, which pulls cytoplasmic components into the vesicles. To demonstrate that this is not a singular phenomenon in a bacterium occurring in an extreme environment, the identification of O-IMVs in pathogenic bacteria was undertaken. With this aim, a structural study by Transmission Electron Microscopy (TEM) and Cryo-transmission electron microscopy (Cryo-TEM) was carried out, confirming that O-IMVs are also secreted by Gram-negative pathogenic bacteria such as Neisseria gonorrhoeae, Pseudomonas aeruginosa PAO1 and Acinetobacter baumannii AB41, in which they represent between 0.23% and 1.2% of total vesicles produced. DNA and ATP, which are components solely found in the cell cytoplasm, were identified within membrane vesicles of these strains. The presence of DNA inside the O-IMVs produced by N. gonorrhoeae was confirmed by gold DNA immunolabeling with a specific monoclonal IgM against double-stranded DNA. A proteomic analysis of N. gonorrhoeae-derived membrane vesicles identified proteins from the cytoplasm and plasma membrane. This confirmation of O-IMV extends the hitherto uniform definition of membrane vesicles in Gram-negative bacteria and explains the presence of components in membrane vesicles such as DNA, cytoplasmic and inner membrane proteins, as well as ATP, detected for the first time. The production of these O-IMVs by pathogenic Gram-negative bacteria opens up new areas of study related to their involvement in lateral gene transfer, the transfer of cytoplasmic proteins, as well as the functionality and role of ATP detected in these new vesicles.
Project description:Characterization of the sRNA content of OMVs harvested from Pseudomonas aeruginosa strain PA14 LB cultue with and without tobramycin (1ug/mL)