Project description:The antibiotic fosfomycin is widely recognized for treatment of lower urinary tract infections caused by Escherichia coli and lately gained importance as a therapeutic option to combat multidrug resistant bacteria. Still, resistance to fosfomycin frequently develops through mutations reducing its uptake. Whereas the inner membrane transport of fosfomycin has been extensively studied in E. coli, its outer membrane (OM) transport remains insufficiently understood. While evaluating minimal inhibitory concentrations in OM porin-deficient mutants, we observed that the E. coli ΔompCΔompF strain is five times more resistant to fosfomycin than the wild type and the respective single mutants. Continuous monitoring of cell lysis of porin-deficient strains in response to fosfomycin additionally indicated the relevance of LamB. Furthermore, the physiological relevance of OmpF, OmpC and LamB for fosfomycin uptake was confirmed by electrophysiological and transcriptional analysis. This study expands the knowledge of how fosfomycin crosses the OM of E. coli.
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:Carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical nosocomial pathogen with limited treatment options. Although antibiotic resistance in CRAB is well-characterized, its interactions with host immunity and the contribution of outer membrane vesicles (OMVs) to pathogenesis remain poorly understood. We examined a clinical CRAB isolate and compared it with the reference strain A19606. Antimicrobial susceptibility testing revealed complete resistance of CRAB to commonly used antibiotics in clinical practice, while A19606 remained susceptible to most agents. In murine intranasal infection models and bone marrow-derived macrophages, CRAB induced significantly stronger activation of inflammatory signaling pathways and elevated levels of pro-inflammatory cytokines relative to A19606. Transcriptomic analysis of infected lung tissue identified differentially expressed genes, enriched for inflammatory response pathways. proteomics showed upregulated proteins in CRAB related to secretion systems. OMVs characterization revealed that CRAB-derived OMVs highly enriched in proteins associated with periplasmic and outer membrane spaces, and more potent in triggering macrophage inflammatory signaling. CRAB displays expansive antibiotic resistance and enhanced pro-inflammatory potential mediated in part by unique OMVs properties. Targeting OMVs formation or host immune modulation may represent effective strategies for combating CRAB infections.
Project description:Large-scale production of bacterial extracellular vesicles is a hurdle for their development as novel cancer immunotherapeutic agents. Here, we developed manufacturing processes for mass production of Escherichia coli EVs known as outer membrane vesicles (OMVs). We present a comprehensive proteome of mass-produced E. coli OMVs.
Project description:Elexacaftor/tezacaftor/ivacaftor (ETI, Trikafta) is highly effective treatment for many cystic fibrosis patients, at least partly because it increases CFTR mediated Cl- and HCO3- secretion by airway epithelial cells leading to improved lung function and less frequent exacerbations and hospitalizations. However, little is known about how ETI affects airway epithelial cells in ways not related to CFTR mediated Cl- and HCO3- secretion, for example how ETI affects the expression of genes other than CFTR or how ETI might affect airway cells’ response to infection. It is established that CF airway cells bearing the delta F 508 mutation the CFTR gene respond characteristically differently from wild type CFTR cells, and we hypothesized that, as a highly effective CFTR modulator, ETI might make airway cells from CF donors respond to pathogen stimulation (Pseudomonas aeruginosa PA14 or outer membrane vesicles isolated from these bacteria) in more the same way that cells from wild type, healthy control cells do. We tested this hypothesis by measuring gene expression responses in polarized primary CF airway cells exposed to ETI alone or ETI in the presence of a pathogen challenge (PA14 or outer membrane vesicles). Responses of CFTR wild type primary CF airway cells to PA14 or outer membrane vesicles was also measured for comparison
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:Uropathogenic bacteria present a variety of mechanisms that allow them to colonize the urinary tract. These mechanisms include biofilm formation, urothelial cell invasion, and the production of adhesins, toxins, and siderophores. Uropathogenic Escherichia coli and Proteus mirabilis are two of the most common etiological agents causing urinary tract infections (UTI). In addition to virulence factors, Gram-negative bacteria can produce outer membrane vesicles (OMVs). The OMVs may have several functions in the context of UTI. In the present work, we isolated and characterized OMVs from two clinical strains: E. coli U144 and P. mirabilis 2921 cultured in Luria-Bertani broth and artificial urine. The OMVs were examined using DLS, NTA and TEM and found to be between 85 and 260 nm in size, the largest being those obtained in artificial urine. All OMVs had a low polydispersity factor and negative charge in their surface. Through proteomic analysis (nanoLC-MS/MS), 282 and 353 proteins were identified in OMVs obtained from E. coli and P. mirabilis LB cultures respectively, and 215 and 103 proteins when they were grown in AU. The majority of proteins were from the bacterial envelope. Also, several proteins related to motility and adhesion were found. The composition of OMVs proteins was different according to the culture medium. Among the identified proteins, those related with zinc and iron uptake systems could have an important role in AU. These results bring us closer to understanding the possible role of OMVs in the pathogenesis of UTIs.