scholarly journals Extracellular vesicles (exosomes) in prokaryotic organisms: role in their biology and realization of their pathogen potential

2020 ◽  
pp. 118-130
Author(s):  
B. A. Shenderov ◽  
A. B. Sinitsa ◽  
M. M. Zakharchenko ◽  
E. I. Tkachenko
Keyword(s):  
Recipient Cell ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Signal Molecules ◽  
Gram Positive Bacteria ◽  
Physiological Processes ◽  
Pathological Conditions

An increasing number of gram-negative and gram-positive bacteria have been observed to secrete outer- membrane vesicles (OMVs) during their growth both under physiological and pathological conditions in vitro and in vivo. These cell-derived particles are present in many — if not all — physiological fluids. They can convey the multiple various low weight effector and signal molecules (proteins, nucleic acids, lipids, and carbohydrates) into the bacterial and host cells that have important functions in their intercellular communication and regulation. Involvement of OMVS in the various biological functions of prokariotic and eukaryotic cells make them to be key players in both physiological processes and also in pathological conditions. Additionally, the ability of OMVs to deliver molecules to recipient cell opens the possibility of their use as novel disease biomarkers and as promising drug/therapy agents. In this Review, we describe the mechanisms through which bacterial OMVs can support the host homeostasis and health and induce host pathology or immune tolerance, and discuss the possibility of these OMVs participate in innovative nanobiotechnologies.

scholarly journals Membrane Vesicle Release in Bacteria, Eukaryotes, and Archaea: a Conserved yet Underappreciated Aspect of Microbial Life

2012 ◽  
Vol 80 (6) ◽  
pp. 1948-1957 ◽  
Author(s):  
Brooke L. Deatherage ◽  
Brad T. Cookson
Keyword(s):  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Immune System ◽  
Vesicle Release ◽  
Communication Signals ◽  
Microbial Life ◽  
Functional Features

ABSTRACTInteraction of microbes with their environment depends on features of the dynamic microbial surface throughout cell growth and division. Surface modifications, whether used to acquire nutrients, defend against other microbes, or resist the pressures of a host immune system, facilitate adaptation to unique surroundings. The release of bioactive membrane vesicles (MVs) from the cell surface is conserved across microbial life, in bacteria, archaea, fungi, and parasites. MV production occurs not onlyin vitrobut alsoin vivoduring infection, underscoring the influence of these surface organelles in microbial physiology and pathogenesis through delivery of enzymes, toxins, communication signals, and antigens recognized by the innate and adaptive immune systems. Derived from a variety of organisms that span kingdoms of life and called by several names (membrane vesicles, outer membrane vesicles [OMVs], exosomes, shedding microvesicles, etc.), the conserved functions and mechanistic strategies of MV release are similar, including the use of ESCRT proteins and ESCRT protein homologues to facilitate these processes in archaea and eukaryotic microbes. Although forms of MV release by different organisms share similar visual, mechanistic, and functional features, there has been little comparison across microbial life. This underappreciated conservation of vesicle release, and the resulting functional impact throughout the tree of life, explored in this review, stresses the importance of vesicle-mediated processes throughout biology.

scholarly journals How the colonic environment influences Enterohaemorrhagic E. coli outer membrane vesicle production, and the interaction between outer membrane vesicles with human host cells

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Daniel Yara ◽  
Regis Stentz ◽  
Tom Wileman ◽  
Stephanie Schuller
Keyword(s):  
Outer Membrane ◽  
Bile Salts ◽  
Membrane Vesicle ◽  
Outer Membrane Proteins ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
T84 Cells ◽  
E Coli

Enterohaemorrhagic E. coli (EHEC) may instigate bloody diarrhoea and haemolytic uraemic syndrome (HUS) due to Shiga toxin (Stx) production. Stx has been detected within outer membrane vesicles (OMVs), which are membrane-derived nanosized proteoliposomes. During colonisation, EHEC encounters many environmental surroundings such as the presence of bile salts and carbon dioxide (CO2). Here, the influence of different intestinal cues on EHEC OMV production was studied. OMV yield was quantified by densitometric analysis of outer membrane proteins F/C and A, following OMV protein separation by SDS-PAGE. Compared to cultures in Luria broth, higher OMV yields were attained following culture in human cell growth medium and simulated colonic environmental medium, with further increases in the presence of bile salts. Interestingly, lower yields were attained in the presence of T84 cells and CO2. The interaction between OMVs and different human cells was also examined by fluorescence microscopy. Here, OMVs incubated with cells showed internalisation by semi confluent but not fully confluent T84 cell monolayers. OMVs were internalised into the lysosomes in confluent Vero and Caco-2 cells, with Stx being transported to the Golgi and then the Endoplasmic reticulum. OMVs were detected within polarised Caco-2 cells, with no impact on the transepithelial electrical resistance by 24 hours. These results suggest that the colonic environmental factors influences OMV production in vivo. Additionally, results highlight the discrepancies which arise when using different cells lines to examine the intestine. Nevertheless, coupled with Stx, OMVs may serve as tools of EHEC which are involved in HUS development.

scholarly journals Outer membrane vesicles catabolize lignin-derived aromatic compounds in Pseudomonas putida KT2440

2020 ◽  
Vol 117 (17) ◽  
pp. 9302-9310 ◽  
Author(s):  
Davinia Salvachúa ◽  
Allison Z. Werner ◽  
Isabel Pardo ◽  
Martyna Michalska ◽  
Brenna A. Black ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Outer Membrane ◽  
Aromatic Compounds ◽  
Value Added ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Pseudomonas Putida Kt2440 ◽  
Rich Media

Lignin is an abundant and recalcitrant component of plant cell walls. While lignin degradation in nature is typically attributed to fungi, growing evidence suggests that bacteria also catabolize this complex biopolymer. However, the spatiotemporal mechanisms for lignin catabolism remain unclear. Improved understanding of this biological process would aid in our collective knowledge of both carbon cycling and microbial strategies to valorize lignin to value-added compounds. Here, we examine lignin modifications and the exoproteome of three aromatic–catabolic bacteria: Pseudomonas putida KT2440, Rhodoccocus jostii RHA1, and Amycolatopsis sp. ATCC 39116. P. putida cultivation in lignin-rich media is characterized by an abundant exoproteome that is dynamically and selectively packaged into outer membrane vesicles (OMVs). Interestingly, many enzymes known to exhibit activity toward lignin-derived aromatic compounds are enriched in OMVs from early to late stationary phase, corresponding to the shift from bioavailable carbon to oligomeric lignin as a carbon source. In vivo and in vitro experiments demonstrate that enzymes contained in the OMVs are active and catabolize aromatic compounds. Taken together, this work supports OMV-mediated catabolism of lignin-derived aromatic compounds as an extracellular strategy for nutrient acquisition by soil bacteria and suggests that OMVs could potentially be useful tools for synthetic biology and biotechnological applications.

scholarly journals Lipopolysaccharide Recognition in the Crossroads of TLR4 and Caspase-4/11 Mediated Inflammatory Pathways

2020 ◽  
Vol 11 ◽  
Author(s):  
Alla Zamyatina ◽  
Holger Heine
Keyword(s):  
Nlrp3 Inflammasome ◽  
Lipid A ◽  
Membrane Vesicles ◽  
Structural Features ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Structural Basis ◽  
Intracellular Bacteria ◽  
Inflammatory Caspases

The innate immune response to lipopolysaccharide is essential for host defense against Gram-negative bacteria. In response to bacterial infection, the TLR4/MD-2 complex that is expressed on the surface of macrophages, monocytes, dendritic, and epithelial cells senses picomolar concentrations of endotoxic LPS and triggers the production of various pro-inflammatory mediators. In addition, LPS from extracellular bacteria which is either endocytosed or transfected into the cytosol of host cells or cytosolic LPS produced by intracellular bacteria is recognized by cytosolic proteases caspase-4/11 and hosts guanylate binding proteins that are involved in the assembly and activation of the NLRP3 inflammasome. All these events result in the initiation of pro-inflammatory signaling cascades directed at bacterial eradication. However, TLR4-mediated signaling and caspase-4/11-induced pyroptosis are largely involved in the pathogenesis of chronic and acute inflammation. Both extra- and intracellular LPS receptors—TLR4/MD-2 complex and caspase-4/11, respectively—are able to directly bind the lipid A motif of LPS. Whereas the structural basis of lipid A recognition by the TLR4 complex is profoundly studied and well understood, the atomic mechanism of LPS/lipid A interaction with caspase-4/11 is largely unknown. Here we describe the LPS-induced TLR4 and caspase-4/11 mediated signaling pathways and their cross-talk and scrutinize specific structural features of the lipid A motif of diverse LPS variants that have been reported to activate caspase-4/11 or to induce caspase-4/11 mediated activation of NLRP3 inflammasome (either upon transfection of LPS in vitro or upon infection of cell cultures with intracellular bacteria or by LPS as a component of the outer membrane vesicles). Generally, inflammatory caspases show rather similar structural requirements as the TLR4/MD-2 complex, so that a “basic” hexaacylated bisphosphorylated lipid A architecture is sufficient for activation. However, caspase-4/11 can sense and respond to much broader variety of lipid A variants compared to the very “narrow” specificity of TLR4/MD-2 complex as far as the number and the length of lipid chains attached at the diglucosamine backbone of lipid A is concerned. Besides, modification of the lipid A phosphate groups with positively charged appendages such as phosphoethanolamine or aminoarabinose could be essential for the interaction of lipid A/LPS with inflammatory caspases and related proteins.

scholarly journals OmpA Protein-Deficient Acinetobacter baumannii Outer Membrane Vesicles Trigger Reduced Inflammatory Response

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 407
Author(s):  
Jūratė Skerniškytė ◽  
Emilija Karazijaitė ◽  
Asta Lučiūnaitė ◽  
Edita Sužiedėlienė
Keyword(s):  
Inflammatory Response ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Proinflammatory Response ◽  
Ompa Protein ◽  
The Impact

Multidrug resistant Acinetobacter baumannii shows a growing number of nosocomial infections worldwide during the last decade. The outer membrane vesicles (OMVs) produced by this bacterium draw increasing attention as a possible treatment target. OMVs have been implicated in the reduction of antibiotic level in the surrounding environment, transfer of virulence factors into the host cells, and induction of inflammatory response. Although the evidence on the involvement of OMVs in A. baumannii pathogenesis is currently growing, their role during inflammation is insufficiently explored. It is likely that bacteria, by secreting OMVs, can expand the area of their exposure and prepare surrounding matrix for infection. Here, we investigated the impact of A. baumannii OMVs on activation of macrophages in vitro. We show that OmpA protein present in A. baumannii OMVs substantially contributes to the proinflammatory response in J774 murine macrophages and to the cell death in both lung epithelium cells and macrophages. The loss of OmpA protein in OMVs, obtained from A. baumannii ∆ompA mutant, resulted in the altered expression of genes coding for IL-6, NLRP3 and IL-1β proinflammatory molecules in macrophages in vitro. These results imply that OmpA protein in bacterial OMVs could trigger a more intense proinflammatory response.

scholarly journals Interaction of the Colicin K Bactericidal Toxin with Components of Its Import Machinery in the Periplasm of Escherichia coli

2010 ◽  
Vol 192 (22) ◽  
pp. 5934-5942 ◽  
Author(s):  
Aurélie Barnéoud-Arnoulet ◽  
Marthe Gavioli ◽  
Roland Lloubès ◽  
Eric Cascales
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Outer Membrane ◽  
Signal Sequence ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Outer Membrane Receptor ◽  
Terminal Domain

ABSTRACT Colicins are bacterial antibiotic toxins produced by Escherichia coli cells and are active against E. coli and closely related strains. To penetrate the target cell, colicins bind to an outer membrane receptor at the cell surface and then translocate their N-terminal domain through the outer membrane and the periplasm. Once fully translocated, the N-terminal domain triggers entry of the catalytic C-terminal domain by an unknown process. Colicin K uses the Tsx nucleoside-specific receptor for binding at the cell surface, the OmpA protein for translocation through the outer membrane, and the TolABQR proteins for the transit through the periplasm. Here, we initiated studies to understand how the colicin K N-terminal domain (KT) interacts with the components of its transit machine in the periplasm. We first produced KT fused to a signal sequence for periplasm targeting. Upon production of KT in wild-type strains, cells became partly resistant to Tol-dependent colicins and sensitive to detergent, released periplasmic proteins, and outer membrane vesicles, suggesting that KT interacts with and titrates components of its import machine. Using a combination of in vivo coimmunoprecipitations and in vitro pulldown experiments, we demonstrated that KT interacts with the TolA, TolB, and TolR proteins. For the first time, we also identified an interaction between the TolQ protein and a colicin translocation domain.

scholarly journals OMV Vaccines and the Role of TLR Agonists in Immune Response

2020 ◽  
Vol 21 (12) ◽  
pp. 4416 ◽  
Author(s):  
Francesca Mancini ◽  
Omar Rossi ◽  
Francesca Necchi ◽  
Francesca Micoli
Keyword(s):  
Immune Responses ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Cell Types ◽  
Outer Membrane Vesicles ◽  
Optimal Size ◽  
Vaccine Platform ◽  
Tlr Agonists

Outer Membrane Vesicles (OMVs) are bacterial nanoparticles that are spontaneously released during growth both in vitro and in vivo by Gram-negative bacteria. They are spherical, bilayered membrane nanostructures that contain many components found within the external surface of the parent bacterium. Naturally, OMVs serve the bacteria as a mechanism to deliver DNA, RNA, proteins, and toxins, as well as to promote biofilm formation and remodel the outer membrane during growth. On the other hand, as OMVs possess the optimal size to be uptaken by immune cells, and present a range of surface-exposed antigens in native conformation and Toll-like receptor (TLR) activating components, they represent an attractive and powerful vaccine platform able to induce both humoral and cell-mediated immune responses. This work reviews the TLR-agonists expressed on OMVs and their capability to trigger individual TLRs expressed on different cell types of the immune system, and then focuses on their impact on the immune responses elicited by OMVs compared to traditional vaccines.

scholarly journals Outer Membrane Vesicles Prime and Activate Macrophage Inflammasomes and Cytokine Secretion In Vitro and In Vivo

2017 ◽  
Vol 8 ◽  
Author(s):  
Jessica D. Cecil ◽  
Neil M. O’Brien-Simpson ◽  
Jason C. Lenzo ◽  
James A. Holden ◽  
William Singleton ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Cytokine Secretion
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