Genome-Wide Assessment of Outer Membrane Vesicle Production in Escherichia coli

Kulp, Adam; Sun, Binggang; Ai, Teresa L.; Manning, Andrew J.; Orench‐Rivera, Nichole; Schmid, Amy K.; Kuehn, Meta J.

doi:10.1371/journal.pone.0139200

Cited by 80 publications

(84 citation statements)

References 67 publications

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“…As other bacteria also secrete EVs, including E. coli , 44, 45 we were curious if they likewise possess similar surface modulatory or inhibitory activities. Using the same concentration (12.5 μg/ml) of pEVs from two additional strains, namely S. epidermidis and E. coli , we tested their ability to bind to polystyrene and inhibit A. baumannii biofilm formation.…”

Section: Resultsmentioning

confidence: 99%

Staphylococcus aureusextracellular vesicles (EVs): surface-binding antagonists of biofilm formation

Mitchell

2017

Mol. BioSyst.

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The prevalence of Staphylococcus aureus worldwide as a nosocomial infectious agent is recognized but the reason behind the spread of this bacterium has remained elusive. Here, we hypothesized that the communication of S. aureus might benefit from it blocking other bacteria from establishing themselves on the surface. This was found to be the case for several pathogens as the S. aureus supernatant curtailed their ability to form biofilms. Subsequent analyses using Acinetobacter baumannii as a model found this effect is primarily mediated by S. aureus’ extracellular vesicles (EVs), which bound to the polystyrene surface. We found the EV-treated surfaces were significantly more hydrophilic after EV treatment, a condition that made it difficult for A. baumannii to initially adhere to the polystyrene surface and reduced its resulting biofilm by up to 93%. Subsequent tests found this also extended to several other bacterial pathogens, with a 40-70% decrease in their biofilm mass. The S. aureus EVs and their activity still remained after the surface was washed with 10% bleach, while the use of ethylenediaminetetraacetic acid (EDTA) removed both the EVs from the surface and their activity.

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Section: Resultsmentioning

confidence: 99%

Staphylococcus aureusextracellular vesicles (EVs): surface-binding antagonists of biofilm formation

Mitchell

2017

Mol. BioSyst.

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“…coli is important for the maintenance of outer membrane integrity. It has been described that mutations in any of the tol-pal genes confer a defect in the outer membrane that leads to increased MV production [19–21]. …”

Section: Resultsmentioning

confidence: 99%

“…A recent study analyzing MV production by the mutant strains of the Keio Collection identified around 150 genes involved in the vesiculation process. It was shown that mutations altering outer membrane structures generally lead to hypervesiculation phenotypes [21]. …”

Section: Introductionmentioning

confidence: 99%

Membrane Vesicles Released by a hypervesiculating Escherichia coli Nissle 1917 tolR Mutant Are Highly Heterogeneous and Show Reduced Capacity for Epithelial Cell Interaction and Entry

et al. 2016

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Membrane vesicles (MVs) produced by Gram-negative bacteria are being explored for novel clinical applications due to their ability to deliver active molecules to distant host cells, where they can exert immunomodulatory properties. MVs released by the probiotic Escherichia coli Nissle 1917 (EcN) are good candidates for testing such applications. However, a drawback for such studies is the low level of MV isolation from in vitro culture supernatants, which may be overcome by the use of mutants in cell envelope proteins that yield a hypervesiculation phenotype. Here, we confirm that a tolR mutation in EcN increases MV production, as determined by protein, LPS and fluorescent lipid measurements. Transmission electron microscopy (TEM) of negatively stained MVs did not reveal significant differences with wild type EcN MVs. Conversely, TEM observation after high-pressure freezing followed by freeze substitution of bacterial samples, together with cryo-TEM observation of plunge-frozen hydrated isolated MVs showed considerable structural heterogeneity in the EcN tolR samples. In addition to common one-bilayer vesicles (OMVs) and the recently described double-bilayer vesicles (O-IMVs), other types of MVs were observed. Time-course experiments of MV uptake in Caco-2 cells using rhodamine- and DiO-labelled MVs evidenced that EcN tolR MVs displayed reduced internalization levels compared to the wild-type MVs. The low number of intracellular MVs was due to a lower cell binding capacity of the tolR-derived MVs, rather than a different entry pathway or mechanism. These findings indicate that heterogeneity of MVs from tolR mutants may have a major impact on vesicle functionality, and point to the need for conducting a detailed structural analysis when MVs from hypervesiculating mutants are to be used for biotechnological applications.

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“…In addition, disruption of crosslinks between the outer membrane and peptidoglycan layer promote MV release (Deatherage et al, 2009; Schwechheimer et al, 2014, 2015). Recently, a high-throughput screen of a whole genome E. coli knockout library identified 171 genes that affect vesicle biogenesis (Kulp et al, 2015). Interestingly, mutants of oxidative stress response pathways correlated with a hypovesiculation phenotype.…”

Section: The Basics: Biogenesis and Functions Of Bacterial Membrane Vmentioning

confidence: 99%

Interspecies Communication between Pathogens and Immune Cells via Bacterial Membrane Vesicles

Jurkoshek

Wang

Athman

et al. 2016

Front. Cell Dev. Biol.

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The production of extracellular vesicles is a universal mechanism for intercellular communication that is conserved across kingdoms. Prokaryotes secrete 50–250 nm membrane vesicles (MVs) in a manner that is regulated by environmental stress and is thought to promote survival. Since many types of host-derived stress are encountered during infection, this implies an important role for MV secretion in bacterial pathogenesis. Accordingly, MVs produced by gram-positive and gram-negative pathogens contain toxins, virulence factors, and other molecules that promote survival in the host. However, recent studies have also shown that bacterial MVs are enriched for molecules that stimulate innate and adaptive immune responses. As an example, MVs may serve multiple, important roles in regulating the host response to Mycobacterium tuberculosis (Mtb), an intracellular pathogen that infects lung macrophages and resides within modified phagosomes. Previously, we demonstrated that Mtb secretes MVs during infection that may modulate infected and uninfected immune cells. Our present data demonstrates that Mtb MVs inhibit the functions of macrophages and T cells, but promote Major Histocompatibility Complex (MHC) class II antigen presentation by dendritic cells. We conclude that bacterial MVs serve dual and opposing roles in the activation of and defense against host immune responses to Mtb and other bacterial pathogens. We also propose that MV secretion is a central mechanism for interspecies communication between bacteria and host cells during infection.

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Genome-Wide Assessment of Outer Membrane Vesicle Production in Escherichia coli

Cited by 80 publications

References 67 publications

Staphylococcus aureusextracellular vesicles (EVs): surface-binding antagonists of biofilm formation

Staphylococcus aureusextracellular vesicles (EVs): surface-binding antagonists of biofilm formation

Membrane Vesicles Released by a hypervesiculating Escherichia coli Nissle 1917 tolR Mutant Are Highly Heterogeneous and Show Reduced Capacity for Epithelial Cell Interaction and Entry

Interspecies Communication between Pathogens and Immune Cells via Bacterial Membrane Vesicles

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