Dataset Information

Outer membrane vesicle and outer membrane of Haemophilus influenzae Rd KW20, Rd ∆yrbE and Rd ∆vacJ

ABSTRACT: Bacterial outer membrane vesicles (OMVs) have important biological roles in pathogenesis and intercellular interactions, but a general mechanism of OMV formation is lacking. Here we show that the VacJ/Yrb ABC transport system, a proposed phospholipid (PL) transporter, is involved in OMV formation. Deletion or repression of VacJ/Yrb increases OMV production in two distantly related Gram-negative bacteria, Haemophilus influenzae and Vibrio cholerae. Within our studies we also analyzed the proteome of the OMV and outer membrane (OM) and found no massive alteration in Haemophilus influenzae Rd KW20, Rd ∆yrbE and Rd ∆vacJ. Lipidome analyses demonstrate that OMVs from VacJ/Yrb-defective mutants in H. influenzae are enriched in PLs and certain fatty acids. Furthermore, we demonstrate that OMV production and regulation of the VacJ/Yrb ABC transport system respond to iron starvation. Our results suggest a new general mechanism of OMV biogenesis based on PL accumulation in the outer leaflet of the outer membrane. This mechanism is highly conserved among Gram-negative bacteria, provides a means for regulation, can account for OMV formation under all growth conditions, and might have important pathophysiological roles in vivo.

INSTRUMENT(S): Q-Tof ultima

ORGANISM(S): Haemophilus Influenzae (strain Atcc 51907 / Dsm 11121 / Kw20 / Rd)

TISSUE(S): Prokaryotic Cell

SUBMITTER: Stefan Schild

LAB HEAD: Stefan Schild

PROVIDER: PXD003249 | Pride | 2016-01-27

REPOSITORIES: Pride

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Publications

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

Roier Sandro S Zingl Franz G FG Cakar Fatih F Durakovic Sanel S Kohl Paul P Eichmann Thomas O TO Klug Lisa L Gadermaier Bernhard B Weinzerl Katharina K Prassl Ruth R Lass Achim A Daum Günther G Reidl Joachim J Feldman Mario F MF Schild Stefan S

Nature communications 20160125

Bacterial outer membrane vesicles (OMVs) have important biological roles in pathogenesis and intercellular interactions, but a general mechanism of OMV formation is lacking. Here we show that the VacJ/Yrb ABC (ATP-binding cassette) transport system, a proposed phospholipid transporter, is involved in OMV formation. Deletion or repression of VacJ/Yrb increases OMV production in two distantly related Gram-negative bacteria, Haemophilus influenzae and Vibrio cholerae. Lipidome analyses demonstrate ...[more]

PMID: 26806181

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Project description:Background: Haemophilus influenzae has an absolute aerobic growth requirement for heme and has developed multiple complex mechanisms to obtain this essential nutrient. Although an understanding of the heme acquisition mechanisms of H. influenzae is emerging, significant gaps remain to be elucidated. In a previous study we utilized H. influenzae strain Rd KW20 to demonstrate the utility of transcriptional profiling in defining the genes exhibiting altered transcription in response to environmental iron and heme levels. The current study expands upon those initial observations by determining the iron/heme regulons of two additional H. influenzae clinical isolates, i.e. the type b isolate 10810 and the nontypeable isolate R2866, to characterize the core iron/heme regulon of the species. Results: A microarray chip was designed to incorporate probes for all of the genes of H. influenzae isolates 10810 and R2866, and microarray studies were performed to compare gene expression under iron/heme-replete and iron/heme-restricted conditions for each isolate. Of 1820 ORFs on the array corresponding to R2866 genes, 363 were significantly differentially expressed. Of these 363 genes, 233 were maximally transcribed under iron/heme-replete conditions and 130 were preferentially transcribed in iron/heme-restricted conditions. Of the 1883 ORFs representing genes of strain10810, 351 were significantly differentially transcribed, 150 of these were preferentially transcribed in iron/heme-replete conditions and 201 were preferentially transcribed in iron/heme-restricted conditions. Comparison of the data sets indicated that 163 genes were similarly regulated in both isolates and that 74 of these also exhibited similar patterns of regulation in strain Rd KW20. Conclusion: This study provides evidence for a core of H. influenzae genes that are regulated by the availability of iron and/or heme in the growth environment. Elucidation of this core regulon provides targets for investigation of genes with an unrecognized role in iron and heme homeostasis, as well as other potential virulence determinants. In addition, the set of core genes potentially provides targets for therapeutic and vaccine designs since these products of these genes are likely to be preferentially expressed during growth in iron/heme restricted sites of the human body. This SuperSeries is composed of the following subset Series: GSE11349: Transcriptional profiling of FeHm effects on Haemophilus influenzae R2866 GSE11354: Transcriptional profiling of FeHm effects on Haemophilus influenzae 10810 Keywords: SuperSeries Refer to individual Series

Project description:. The transition of the opportunistic pathogen Pseudomonas aeruginosa from free-living bacteria into surface-associated biofilm communities represents a viable target for the prevention and treatment of chronic infectious disease. We have established a proteomics platform that identified 2443 and 1142 high-confidence proteins in P. aeruginosa whole cells and outer membrane vesicles (OMVs), respectively, at three time points during biofilm development. Analysis of cellular systems, specifically the phenazine biosynthetic pathway, demonstrates that whole cell protein abundance correlates to end product (i.e., pyocyanin) concentrations in biofilm but not planktonic cultures. Furthermore, increased cellular protein abundance in this pathway results in quantifiable pyocyanin in early biofilm OMVs, and OMVs from both growth modes isolated at later time points. Overall, our data indicate that the OMVs being released from the surface of the biofilm whole cells have unique proteomes in comparison to their planktonic counterparts. The relative abundance of OMV proteins from various subcellular sources showed considerable differences between the two growth modes over time, supporting the existence and preferential activation of multiple OMV biogenesis mechanisms under different conditions. The consistent detection of cytoplasmic proteins in the OMV subproteome suggests that these proteins may contribute a small but functionally relevant component to biofilm OMVs. Direct comparisons of outer membrane protein abundance levels between OMVs and whole cells shows ratios that vary greatly from 1:1, and supports previous studies that advocate specific inclusion, or “packaging”, of proteins into OMVs. The detailed analysis of packaged protein groups indicates biogenesis mechanisms that involve untethered, rather than absent, peptidoglycan-binding proteins. Collectively, individual protein and biological system analyses of biofilm OMVs show that drug-binding cytoplasmic proteins and porins are shuttled from the whole cell into the OMVs, potentially contributing to the antibiotic resistance of P. aeruginosa whole cells within biofilms.

Dataset Information

Outer membrane vesicle and outer membrane of Haemophilus influenzae Rd KW20, Rd ∆yrbE and Rd ∆vacJ

Publications

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

Similar Datasets

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