A novel mechanism for the biogenesis of outer membrane vesicles in Gram-negative bacteria

Roier, Sandro; Zingl, Franz G.; Çakar, Fatih; Durakovic, Sanel; Kohl, Paul; Eichmann, Thomas O.; Klug, Lisa; Gadermaier, Bernhard; Weinzerl, Katharina; Ruth, Peter; Lass, Achim; Daum, Günther; Reidl, Joachim; Feldman, Mario F.; Schild, Stefan

doi:10.1038/ncomms10515

Cited by 364 publications

(457 citation statements)

References 54 publications

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“…Therefore this avenue of investigation was not pursued further. These data thus confirmed that the observed increase in DNA release events under competence-inducing conditions was not due to increased cell death as a result of an iron deficiency nor was it likely due to increased biogenesis of outer-membrane vesicles known to occur in H. influenzae in response to iron starvation (60). Although competence has long been associated with the uptake of DNA, here we provide evidence that, in NTHI, induction of competence is also associated with the increased release of DNA and likely also the associated DNABII proteins.…”

Section: Resultssupporting

confidence: 75%

NontypeableHaemophilus influenzaereleases DNA and DNABII proteins via a T4SS-like complex and ComE of the type IV pilus machinery

Jurcisek

Brockman

Novotny

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Biofilms formed by nontypeable Haemophilus influenzae (NTHI) are central to the chronicity, recurrence, and resistance to treatment of multiple human respiratory tract diseases including otitis media, chronic rhinosinusitis, and exacerbations of both cystic fibrosis and chronic obstructive pulmonary disease. Extracellular DNA (eDNA) and associated DNABII proteins are essential to the overall architecture and structural integrity of biofilms formed by NTHI and all other bacterial pathogens tested to date. Although cell lysis and outermembrane vesicle extrusion are possible means by which these canonically intracellular components might be released into the extracellular environment for incorporation into the biofilm matrix, we hypothesized that NTHI additionally used a mechanism of active DNA release. Herein, we describe a mechanism whereby DNA and associated DNABII proteins transit from the bacterial cytoplasm to the periplasm via an inner-membrane pore complex (TraC and TraG) with homology to type IV secretion-like systems. These components exit the bacterial cell through the ComE pore through which the NTHI type IV pilus is expressed. The described mechanism is independent of explosive cell lysis or cell death, and the release of DNA is confined to a discrete subpolar location, which suggests a novel form of DNA release from viable NTHI. Identification of the mechanisms and determination of the kinetics by which critical biofilm matrix-stabilizing components are released will aid in the design of novel biofilmtargeted therapeutic and preventative strategies for diseases caused by NTHI and many other human pathogens known to integrate eDNA and DNABII proteins into their biofilm matrix.eDNA | Tra | secretin | IHF | HU B iofilms contribute substantially to the chronic and recurrent nature of many bacterial diseases of humans and animals, including those of the airway, urogenital tract, skin, and oral cavity (1-3). Bacteria within a biofilm are protected from environmental stresses by a self-produced extracellular matrix, called the extrapolymeric substance (EPS), whose composition varies greatly depending upon the microbes that produce it and the environment in which it is formed. Despite vast compositional variability, the EPS is typically composed of a complex mixture of lipopolysaccharides, proteins, lipids, glycolipids, and nucleic acids (4). Extracellular DNA (eDNA) is a major constituent of the EPS formed by multiple human pathogens (5-7) and serves diverse roles within the bacterial biofilm. eDNA provides structural stability to the matrix, acts as a sink for antimicrobial peptides, protects resident bacteria from the host immune response, provides a source of "common goods" for the resident bacteria, acts as a universal structural material conducive to microbial community architecture, and facilitates the uptake of genetic material between bacterial species via a process known as horizontal gene transfer (5,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Members of the DNABII family of DNA-binding proteins, integ...

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Section: Resultssupporting

confidence: 75%

NontypeableHaemophilus influenzaereleases DNA and DNABII proteins via a T4SS-like complex and ComE of the type IV pilus machinery

Jurcisek

Brockman

Novotny

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…In Gram-negative bacteria, endolysin and the ABC transporter system positively affect MV production via different molecular mechanisms (45,46). How singlemembrane, Gram-positive bacteria that have a thick peptidoglycan cell wall produce MVs is still unknown.…”

Section: Discussionmentioning

confidence: 99%

Immunoactive Clostridial Membrane Vesicle Production Is Regulated by a Sporulation Factor

et al. 2017

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Recently, many Gram-positive bacteria as well as Gram-negative bacteria have been reported to produce membrane vesicles (MVs), but little is known regarding the regulators involved in MV formation. We found that a Gram-positive anaerobic pathogen, Clostridium perfringens, produces MVs predominantly containing membrane proteins and cell wall components. These MVs stimulated proinflammatory cytokine production in mouse macrophage-like cells. We suggested that MVs induced interleukin-6 production through the Toll-like receptor 2 (TLR2) signaling pathway. Thus, the MV could have a role in the bacterium-host interaction and bacterial infection pathogenesis. Moreover, we found that the sporulation master regulator gene spo0A was required for vesiculogenesis. A conserved, phosphorylated aspartate residue of Spo0A was indispensable for MV production, suggesting that the phosphorylation of Spo0A triggers MV production. Multiple orphan sensor kinases necessary for sporulation were also required to maximize MV production. These findings imply that C. perfringens actively produces immunoactive MVs in response to the environment changing, as recognized by membrane-spanning sensor kinases and by modulating the phosphorylation level of Spo0A.

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“…Bacterial OMVs can allow trafficking of biomolecules to other cells in their environment. Studies showed that OMVs are definitive components of the Pa and NTHI biofilm EPS (28,29), and they contain cargo that may contribute to the matrix EPS ( recently been identified (30), their precise role in modulating biofilm/EPS structure has not been evaluated.…”

Section: Outer Membrane Vesicles (Omvs)mentioning

confidence: 99%

What's on the Outside Matters: The Role of the Extracellular Polymeric Substance of Gram-negative Biofilms in Evading Host Immunity and as a Target for Therapeutic Intervention

Gunn

Bakaletz

Wozniak

2016

Journal of Biological Chemistry

147

133

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Biofilms are organized multicellular communities encased in an extracellular polymeric substance (EPS). Biofilm-resident bacteria resist immunity and antimicrobials. The EPS provides structural stability and presents a barrier; however, a complete understanding of how EPS structure relates to biological function is lacking. This review focuses on the EPS of three Gram-negative pathogens: Pseudomonas aeruginosa, nontypeable Haemophilus influenzae, and Salmonella enterica serovar Typhi/Typhimurium. Although EPS proteins and polysaccharides are diverse, common constituents include extracellular DNA, DNABII (DNA binding and bending) proteins, pili, flagella, and outer membrane vesicles. The EPS biochemistry promotes recalcitrance and informs the design of therapies to reduce or eliminate biofilm burden.

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A novel mechanism for the biogenesis of outer membrane vesicles in Gram-negative bacteria

Cited by 364 publications

References 54 publications

NontypeableHaemophilus influenzaereleases DNA and DNABII proteins via a T4SS-like complex and ComE of the type IV pilus machinery

NontypeableHaemophilus influenzaereleases DNA and DNABII proteins via a T4SS-like complex and ComE of the type IV pilus machinery

Immunoactive Clostridial Membrane Vesicle Production Is Regulated by a Sporulation Factor

What's on the Outside Matters: The Role of the Extracellular Polymeric Substance of Gram-negative Biofilms in Evading Host Immunity and as a Target for Therapeutic Intervention

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