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https://www.readbyqxmd.com/read/28530169/commensal-derived-omvs-elicit-a-mild-proinflammatory-response-in-intestinal-epithelial-cells
#1
Daniel A Patten, Enas Hussein, Scott P Davies, Paul N Humphreys, Andrew Collett
Under normal physiological conditions, the intestinal immunity remains largely hyporesponsive to the commensal microbiota, yet also retains the inherent ability to rapidly respond to pathogenic antigens. However, immunomodulatory activities of extracellular products from commensal bacteria have been little studied, with previous investigations generally utilizing the live bacterium to study microbiota-epithelial interactions. In this study, we demonstrate that extracellular products of a commensal bacterium, Escherichia coli C25, elicit a moderate release of proinflammatory IL-8 and stimulate transcriptional up-regulation of Toll-like receptors (TLRs) in intestinal epithelial cell lines HT29-19A and Caco-2...
May 22, 2017: Microbiology
https://www.readbyqxmd.com/read/28522212/bioengineering-bacterial-outer-membrane-vesicles-as-vaccine-platform
#2
REVIEW
Matthias J H Gerritzen, Dirk E Martens, René H Wijffels, Leo van der Pol, Michiel Stork
Outer membrane vesicles (OMVs) are naturally non-replicating, highly immunogenic spherical nanoparticles derived from Gram-negative bacteria. OMVs from pathogenic bacteria have been successfully used as vaccines against bacterial meningitis and sepsis among others and the composition of the vesicles can easily be engineered. OMVs can be used as a vaccine platform by engineering heterologous antigens to the vesicles. The major advantages of adding heterologous proteins to the OMV are that the antigens retain their native conformation, the ability of targeting specific immune responses, and a single production process suffices for many vaccines...
May 15, 2017: Biotechnology Advances
https://www.readbyqxmd.com/read/28505330/acinetobacter-baumannii-transfers-the-blandm-1-gene-via-outer-membrane-vesicles
#3
Somdatta Chatterjee, Ayan Mondal, Shravani Mitra, Sulagna Basu
Objectives: To investigate the transmission of the gene encoding New Delhi metallo-β-lactamase-1 ( bla NDM-1 ) through outer membrane vesicles (OMVs) released from an Acinetobacter baumannii strain (A_115). Methods: Isolation and purification of OMVs by density gradient from a carbapenem-resistant clinical strain of A. baumannii harbouring plasmid-mediated bla NDM-1 and aac(6')-Ib-cr genes was performed. DNA was purified from the OMVs and used for PCR and dot-blot analysis...
May 12, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28501509/designer-outer-membrane-vesicles-as-immunomodulatory-systems-reprogramming-bacteria-for-vaccine-delivery
#4
Yehou M D Gnopo, Hannah C Watkins, Taylor C Stevenson, Matthew P DeLisa, David Putnam
Vaccines often require adjuvants to be effective. Traditional adjuvants, like alum, activate the immune response but in an uncontrolled way. Newer adjuvants help to direct the immune response in a more coordinated fashion. Here, we review the opportunity to use the outer membrane vesicles (OMVs) of bacteria as a way to modulate the immune response toward making more effective vaccines. This review outlines the different types of OMVs that have been investigated for vaccine delivery and how they are produced...
May 10, 2017: Advanced Drug Delivery Reviews
https://www.readbyqxmd.com/read/28488744/membrane-vesicle-secretion-and-prophage-induction-in-multidrug-resistant-stenotrophomonas-maltophilia-in-response-to-ciprofloxacin-stress
#5
Simon Devos, Wouter Van Putte, Jolien Vitse, Gonzalez Van Driessche, Stephan Stremersch, Wim Van Den Broek, Koen Raemdonck, Kevin Braeckmans, Henning Stahlberg, Misha Kudryashev, Savvas N Savvides, Bart Devreese
Several bacterial species produce membrane vesicles (MVs) in response to antibiotic stress. However, the biogenesis and role of MVs in bacterial antibiotic resistance mechanisms have remained unclear. Here we studied the effect of the fluoroquinolone ciprofloxacin on MV secretion by Stenotrophomonas maltophilia using a combination of electron microscopy and proteomic approaches. We found that in addition to the classical outer membrane vesicles (OMV), ciprofloxacin-stimulated cultures produced larger vesicles containing both outer and inner membranes termed outer-inner membrane vesicles (OIMV), and that such MVs are enriched with cytosolic proteins...
May 10, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28487177/predicted-vs-observed-effectiveness-of-outer-membrane-vesicle-omv-vaccines-against-meningococcal-serogroup-b-disease-systematic-review
#6
Thomas Harder, Judith Koch, Ole Wichmann, Wiebke Hellenbrand
IMPORTANCE: Human serum bactericidal antibody levels (hSBA) are commonly used as an immune correlate of protection after vaccination against meningococcal disease. We performed a systematic review of how well this marker correlates with protection induced by outer membrane vesicle (OMV) vaccines against meningococcal B (MenB) disease. OBJECTIVE: To compare vaccine effectiveness (VE) of OMV vaccines against MenB predicted by hSBA (predicted protection) to VE from clinical studies (observed protection)...
May 6, 2017: Journal of Infection
https://www.readbyqxmd.com/read/28483926/some-gram-negative-lipoproteins-keep-their-surface-topology-when-transplanted-from-one-species-to-another-and-deliver-foreign-polypeptides-to-the-bacterial-surface
#7
Laura Fantappiè, Carmela Irene, Micaela De Santis, Alessandro Armini, Assunta Gagliardi, Michele Tomasi, Matteo Parri, Valeria Cafardi, Serena Bonomi, Luisa Ganfini, Francesca Zerbini, Ilaria Zanella, Chiara Carnemolla, Luca Bini, Alberto Grandi, Guido Grandi
In Gram-negative bacteria, outer membrane-associated lipoproteins can either face the periplasm or protrude out of the bacterial surface. The mechanisms involved in lipoprotein transport through the outer membrane are not fully elucidated. Some lipoproteins reach the surface by using species-specific transport machinery. By contrast, a still poorly characterized group of lipoproteins appears to always cross the outer membrane, even when transplanted from one organism to another. To investigate such lipoproteins, we tested the expression and compartmentalization in E...
May 8, 2017: Molecular & Cellular Proteomics: MCP
https://www.readbyqxmd.com/read/28447389/outer-membrane-vesicles-from-fibrobacter-succinogenes-s85-contain-an-array-of-carbohydrate-active-enzymes-with-versatile-polysaccharide-degrading-capacity
#8
Magnus Ø Arntzen, Anikó Várnai, Roderick I Mackie, Vincent G H Eijsink, Phillip B Pope
Fibrobacter succinogenes is an anaerobic bacterium naturally colonizing the rumen and cecum of herbivores where it utilizes an enigmatic mechanism to deconstruct cellulose into cellobiose and glucose, which serve as carbon sources for growth. Here, we illustrate that outer membrane vesicles (OMVs) released by F. succinogenes are enriched with carbohydrate-active enzymes and that intact OMVs were able to depolymerize a broad range of linear and branched hemicelluloses and pectin, despite the inability of F. succinogenes to utilize non-cellulosic (pentose) sugars for growth...
April 26, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28430970/helicobacter-pylori-outer-membrane-vesicles-inhibit-human-t-cell-responses-via-induction-of-monocyte-cox-2-expression
#9
Barry D Hock, Judith L McKenzie, Jacqueline I Keenan
The modulation of T cell responses by Helicobacter pylori is thought to potentiate both H. pylori persistence and development of gastric pathologies including cancer. Release of outer membrane vesicles (OMV) by H. pylori provides a potential vehicle for modulation of the immune system. Although OMV are thought to have T cell suppressive activity this has not yet been demonstrated. Their suppressive activity was investigated in this study using the responses of peripheral blood mononuclear cells (PBMC) to T cell stimuli as a readout...
April 18, 2017: Pathogens and Disease
https://www.readbyqxmd.com/read/28416709/spheres-of-hope-packets-of-doom-the-good-and-bad-of-outer-membrane-vesicles-in-interspecies-and-ecological-dynamics
#10
Jonathan B Lynch, Rosanna A Alegado
Outer membrane vesicles (OMVs) are proteoliposome nanoparticles ubiquitously produced by Gram-negative bacteria. Typically bearing similar composition to the outer membrane and periplasm of the cells from which they are derived, OMVs package an array of proteins, lipids, and nucleic acids. Once considered inconsequential byproducts of bacterial growth, OMVs have since been demonstrated to mediate cellular stress relief, promote horizontal gene transfer and antimicrobial activity, and elicit metazoan inflammation...
April 17, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28369428/novel-approaches-to-neisseria-meningitidis-vaccine-design
#11
Myron Christodoulides, John Heckels
A range of vaccines is available for preventing life-threatening diseases caused by infection with Neisseria meningitidis (meningococcus, Men). Capsule polysaccharide (CPS)-conjugate vaccines are successful prophylactics for serogroup MenA, MenC, MenW and MenY infections and outer membrane vesicle (OMV) vaccines have been used successfully for controlling clonal serogroup MenB infections. MenB vaccines based on recombinant proteins identified by reverse vaccinology (Bexsero®) and proteomics (Trumenba®) approaches have recently been licensed and Bexsero® has been introduced into the UK infant immunization program...
March 22, 2017: Pathogens and Disease
https://www.readbyqxmd.com/read/28357390/breaking-the-bilayer-omv-formation-during-environmental-transitions
#12
COMMENT
Katherine E Bonnington, Meta J Kuehn
Gram-negative bacteria maintain the barrier properties of the outer membrane (OM) in a wide array of physiological conditions despite their inability to degrade lipopolysaccharide (LPS) and protein material present in the outer leaflet of the OM. Through characterization of the native dynamics of outer membrane LPS change we recently described a mechanism in which these diderm organisms overcome this design flaw. In response to different environmental stimuli Salmonellaenterica modulates the export of specific structural variants of lipid A via outer membrane vesicles (OMVs)...
February 3, 2017: Microbial Cell
https://www.readbyqxmd.com/read/28357362/bacterial-outer-membrane-vesicle-biogenesis-a-new-mechanism-and-its-implications
#13
COMMENT
Sandro Roier, Franz G Zingl, Fatih Cakar, Stefan Schild
Outer membrane vesicle (OMV) release by Gram-negative bacteria has been observed and studied for decades. First considered as a by-product of cell lysis, it soon became evident that OMVs are actively secreted from the outer membrane (OM) of Gram-negative bacteria. Accordingly, these small particles (~ 10-300 nm in diameter) consist mainly of OM components like phospholipids (PLs), OM proteins, and lipopolysaccharides or lipooligosaccharides. However, OMVs may also comprise periplasmic, inner membrane, or cytoplasmic components...
May 10, 2016: Microbial Cell
https://www.readbyqxmd.com/read/28356256/recent-progress-in-the-prevention-of-serogroup-b-meningococcal-disease
#14
REVIEW
Ian M Feavers, Martin C J Maiden
The widespread use of meningococcal polysaccharide conjugate vaccines has highlighted the challenge of providing protection against serogroup B disease. Over a period of 4 decades, vaccine development has focused on subcapsular protein antigens, first with outer membrane vesicle (OMV) vaccines against epidemic outbreaks, and more recently on new multicomponent vaccines designed to offer better cross-protection against the antigenically diverse strains responsible for endemic disease. Because of the low incidence of meningococcal disease, the protective efficacy of these vaccines has not been determined in clinical studies, and their licensure has been based on serological data; however, the serological assays used to predict protective coverage have limitations...
May 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28348410/a-pseudomonas-t6ss-effector-recruits-pqs-containing-outer-membrane-vesicles-for-iron-acquisition
#15
Jinshui Lin, Weipeng Zhang, Juanli Cheng, Xu Yang, Kaixiang Zhu, Yao Wang, Gehong Wei, Pei-Yuan Qian, Zhao-Qing Luo, Xihui Shen
Iron sequestration by host proteins contributes to the defence against bacterial pathogens, which need iron for their metabolism and virulence. A Pseudomonas aeruginosa mutant lacking all three known iron acquisition systems retains the ability to grow in media containing iron chelators, suggesting the presence of additional pathways involved in iron uptake. Here we screen P. aeruginosa mutants defective in growth in iron-depleted media and find that gene PA2374, proximal to the type VI secretion system H3 (H3-T6SS), functions synergistically with known iron acquisition systems...
March 28, 2017: Nature Communications
https://www.readbyqxmd.com/read/28320881/lpto-pg0027-is-required-for-lipid-a-1-phosphatase-activity-in-porphyromonas-gingivalis-w50
#16
Minnie Rangarajan, Joseph Aduse-Opoku, Ahmed Hashim, Graham McPhail, Zofia Luklinska, M Florencia Haurat, Mario F Feldman, Michael A Curtis
Porphyromonas gingivalis produces outer-membrane vesicles (OMVs) rich in virulence factors including cysteine-proteases and A-LPS, one of the two lipopolysaccharides (LPS) produced by this organism. Previous studies had suggested that A-LPS together with PG0027, an outer-membrane (OM) protein, may be involved in OMV-formation. Their roles in this process were examined using parent W50 and mutant ΔPG0027 strains. Inactivation of PG0027 caused a reduction in yield of OMVs. Lipid A from cells and OMVs of P. gingivalis W50 and ΔPG0027 strains were analysed by matrix-assisted laser-desorption-ionisation-time of flight mass spectrometry (MALDI-TOF- MS)...
March 20, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28287548/legionella-pneumophila-outer-membrane-vesicles-isolation-and-analysis-of-their-pro-inflammatory-potential-on-macrophages
#17
Anna Lena Jung, Kerstin Hoffmann, Christina E Herkt, Christine Schulz, Wilhelm Bertrams, Bernd Schmeck
Bacteria are able to secrete a variety of molecules via various secretory systems. Besides the secretion of molecules into the extracellular space or directly into another cell, Gram-negative bacteria can also form outer membrane vesicles (OMVs). These membrane vesicles can deliver their cargo over long distances, and the cargo is protected from degradation by proteases and nucleases. Legionella pneumophila (L. pneumophila) is an intracellular, Gram-negative pathogen that causes a severe form of pneumonia. In humans, it infects alveolar macrophages, where it blocks lysosomal degradation and forms a specialized replication vacuole...
February 22, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28272393/experimental-vaccine-induces-th1-driven-immune-responses-and-resistance-to-neisseria-gonorrhoeae-infection-in-a-murine-model
#18
Y Liu, L A Hammer, W Liu, M M Hobbs, R A Zielke, A E Sikora, A E Jerse, N K Egilmez, M W Russell
Female mice were immunized intravaginally with gonococcal outer membrane vesicles (OMVs) plus microencapsulated interleukin-12 (IL-12), and challenged using an established model of genital infection with Neisseria gonorrhoeae. Whereas sham-immunized and control animals cleared the infection in 10-13 days, those immunized with OMV plus IL-12 cleared infection with homologous gonococcal strains in 6-9 days. Significant protection was also seen after challenge with antigenically distinct strains of N. gonorrhoeae, and protective anamnestic immunity persisted for at least 6 months after immunization...
March 8, 2017: Mucosal Immunology
https://www.readbyqxmd.com/read/28255538/porphyromonas-gingivalis-derived-outer-membrane-vesicles-promote-calcification-of-vascular-smooth-muscle-cells-through-erk1-2-runx2
#19
Wen Wei Yang, Bin Guo, Wen Yuan Jia, Yue Jia
The outer membrane vesicle (OMV) derived from Porphyromonas gingivalis plays an essential role in causing inflammation which, in turn, plays an important part in the pathogenesis of cardiovascular diseases such as atherosclerosis and thromboembolism. However, the contribution of oral bacteria to vascular calcification is yet to be determined. Here, we evaluated the effect of OMV on vascular smooth muscle cell (VSMC) calcification both in vitro and ex vivo. We established a reproducible P. gingivalis OMV-induced differentiation and calcification model of VSMCs in vitro...
December 2016: FEBS Open Bio
https://www.readbyqxmd.com/read/28246335/dynamic-regulation-of-extracellular-atp-in-escherichia-coli
#20
Cora Lilia Alvarez, Gerardo Corradi, Natalia Lauri, Irene Marginedas-Freixa, María Florencia Leal Denis, Nicolás Enrique, Sabina María Mate, Verónica Milesi, Mariano Anibal Ostuni, Vanesa Herlax, Pablo Julio Schwarzbaum
We studied the kinetics of extracellular ATP (ATPe) in Escherichia coli and their outer membrane vesicles (OMVs) stimulated with amphipatic peptides melittin (MEL) and mastoparan 7 (MST7). Real-time luminometry was used to measure ATPe kinetics, ATP release, and ATPase activity. The latter was also determined by following [(32)P]Pi released from [γ-(32)P]ATP. E. coli was studied alone, co-incubated with Caco-2 cells, or in rat jejunum segments. In E. coli, the addition of [γ-(32)P]ATP led to the uptake and subsequent hydrolysis of ATPe...
April 4, 2017: Biochemical Journal
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