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Johnston EL, Zavan L, Bitto NJ, Petrovski S, Hill AF, Kaparakis-Liaskos M. Planktonic and Biofilm-Derived Pseudomonas aeruginosa Outer Membrane Vesicles Facilitate Horizontal Gene Transfer of Plasmid DNA. Microbiol Spectr 2023; 11:e0517922. [PMID: 36946779 PMCID: PMC10100964 DOI: 10.1128/spectrum.05179-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/12/2023] [Indexed: 03/23/2023] Open
Abstract
Outer membrane vesicles (OMVs) produced by Gram-negative bacteria package various cargo, including DNA that can be transferred to other bacteria or to host cells. OMV-associated DNA has been implicated in mediating horizontal gene transfer (HGT) between bacteria, which includes the dissemination of antibiotic resistance genes within and between bacterial species. Despite the known ability of OMVs to mediate HGT, the mechanisms of DNA packaging into OMVs remain poorly characterized, as does the effect of bacterial growth conditions on the DNA cargo composition of OMVs and their subsequent abilities to mediate HGT. In this study, we examined the DNA content of OMVs produced by the opportunistic pathogen Pseudomonas aeruginosa grown in either planktonic or biofilm conditions. Analysis of planktonic growth-derived OMVs revealed their ability to package and protect plasmid DNA from DNase degradation and to transfer plasmid-encoded antibiotic resistance genes to recipient, antibiotic-sensitive P. aeruginosa bacteria at a greater efficiency than transformation with plasmid alone. Comparisons of planktonic and biofilm-derived P. aeruginosa OMVs demonstrated that biofilm-derived OMVs were smaller but were associated with more plasmid DNA than planktonic-derived OMVs. Additionally, biofilm-derived P. aeruginosa OMVs were more efficient in the transformation of competent P. aeruginosa bacteria, compared to transformations with an equivalent number of planktonic-derived OMVs. The findings of this study highlight the importance of bacterial growth conditions for the packaging of DNA within P. aeruginosa OMVs and their ability to facilitate HGT, thus contributing to the spread of antibiotic resistance genes between P. aeruginosa bacteria. IMPORTANCE Bacterial membrane vesicles (BMVs) mediate interbacterial communication, and their ability to package DNA specifically contributes to biofilm formation, antibiotic resistance, and HGT between bacteria. However, the ability of P. aeruginosa OMVs to mediate HGT has not yet been demonstrated. Here, we reveal that P. aeruginosa planktonic and biofilm-derived OMVs can deliver plasmid-encoded antibiotic resistance to recipient P. aeruginosa. Additionally, we demonstrated that P. aeruginosa biofilm-derived OMVs were associated with more plasmid DNA compared to planktonic-derived OMVs and were more efficient in the transfer of plasmid DNA to recipient bacteria. Overall, this demonstrated the ability of P. aeruginosa OMVs to facilitate the dissemination of antibiotic resistance genes, thereby enabling the survival of susceptible bacteria during antibiotic treatment. Investigating the roles of biofilm-derived BMVs may contribute to furthering our understanding of the role of BMVs in HGT and the spread of antibiotic resistance in the environment.
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Affiliation(s)
- Ella L. Johnston
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, Victoria, Australia
| | - Lauren Zavan
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, Victoria, Australia
| | - Natalie J. Bitto
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, Victoria, Australia
| | - Steve Petrovski
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - Andrew F. Hill
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, Victoria, Australia
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, Australia
| | - Maria Kaparakis-Liaskos
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, Victoria, Australia
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Gilmore WJ, Johnston EL, Bitto NJ, Zavan L, O'Brien-Simpson N, Hill AF, Kaparakis-Liaskos M. Bacteroides fragilis outer membrane vesicles preferentially activate innate immune receptors compared to their parent bacteria. Front Immunol 2022; 13:970725. [DOI: 10.3389/fimmu.2022.970725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
The release of bacterial membrane vesicles (BMVs) has become recognized as a key mechanism used by both pathogenic and commensal bacteria to activate innate immune responses in the host and mediate immunity. Outer membrane vesicles (OMVs) produced by Gram-negative bacteria can harbor various immunogenic cargo that includes proteins, nucleic acids and peptidoglycan, and the composition of OMVs strongly influences their ability to activate host innate immune receptors. Although various Gram-negative pathogens can produce OMVs that are enriched in immunogenic cargo compared to their parent bacteria, the ability of OMVs produced by commensal organisms to be enriched with immunostimulatory contents is only recently becoming known. In this study, we investigated the cargo associated with OMVs produced by the intestinal commensal Bacteroides fragilis and determined their ability to activate host innate immune receptors. Analysis of B. fragilis OMVs revealed that they packaged various biological cargo including proteins, DNA, RNA, lipopolysaccharides (LPS) and peptidoglycan, and that this cargo could be enriched in OMVs compared to their parent bacteria. We visualized the entry of B. fragilis OMVs into intestinal epithelial cells, in addition to the ability of B. fragilis OMVs to transport bacterial RNA and peptidoglycan cargo into Caco-2 epithelial cells. Using HEK-Blue reporter cell lines, we identified that B. fragilis OMVs could activate host Toll-like receptors (TLR)-2, TLR4, TLR7 and nucleotide-binding oligomerization domain-containing protein 1 (NOD1), whereas B. fragilis bacteria could only induce the activation of TLR2. Overall, our data demonstrates that B. fragilis OMVs activate a broader range of host innate immune receptors compared to their parent bacteria due to their enrichment of biological cargo and their ability to transport this cargo directly into host epithelial cells. These findings indicate that the secretion of OMVs by B. fragilis may facilitate immune crosstalk with host epithelial cells at the gastrointestinal surface and suggests that OMVs produced by commensal bacteria may preferentially activate host innate immune receptors at the mucosal gastrointestinal tract.
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Kienes I, Johnston EL, Bitto NJ, Kaparakis-Liaskos M, Kufer TA. Bacterial subversion of NLR-mediated immune responses. Front Immunol 2022; 13:930882. [PMID: 35967403 PMCID: PMC9367220 DOI: 10.3389/fimmu.2022.930882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/04/2022] [Indexed: 11/23/2022] Open
Abstract
Members of the mammalian Nod-like receptor (NLR) protein family are important intracellular sensors for bacteria. Bacteria have evolved under the pressure of detection by host immune sensing systems, leading to adaptive subversion strategies to dampen immune responses for their benefits. These include modification of microbe-associated molecular patterns (MAMPs), interception of innate immune pathways by secreted effector proteins and sophisticated instruction of anti-inflammatory adaptive immune responses. Here, we summarise our current understanding of subversion strategies used by bacterial pathogens to manipulate NLR-mediated responses, focusing on the well-studied members NOD1/2, and the inflammasome forming NLRs NLRC4, and NLRP3. We discuss how bacterial pathogens and their products activate these NLRs to promote inflammation and disease and the range of mechanisms used by bacterial pathogens to evade detection by NLRs and to block or dampen NLR activation to ultimately interfere with the generation of host immunity. Moreover, we discuss how bacteria utilise NLRs to facilitate immunotolerance and persistence in the host and outline how various mechanisms used to attenuate innate immune responses towards bacterial pathogens can also aid the host by reducing immunopathologies. Finally, we describe the therapeutic potential of harnessing immune subversion strategies used by bacteria to treat chronic inflammatory conditions.
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Affiliation(s)
- Ioannis Kienes
- Department of Immunology, University of Hohenheim, Stuttgart, Germany
| | - Ella L. Johnston
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, VIC, Australia
| | - Natalie J. Bitto
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, VIC, Australia
| | - Maria Kaparakis-Liaskos
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
- Research Centre for Extracellular Vesicles, La Trobe University, Melbourne, VIC, Australia
| | - Thomas A. Kufer
- Department of Immunology, University of Hohenheim, Stuttgart, Germany
- *Correspondence: Thomas A. Kufer,
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Bitto NJ, Kaparakis-Liaskos M. Methods of Bacterial Membrane Vesicle Production, Purification, Quantification, and Examination of Their Immunogenic Functions. Methods Mol Biol 2022; 2523:43-61. [PMID: 35759190 DOI: 10.1007/978-1-0716-2449-4_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Bacterial membrane vesicles (BMVs) released by Gram-negative and Gram-positive bacteria are a bona fide secretion system that enable the dissemination of bacterial effector molecules, and can trigger a range of responses in the host. The study of BMV production, composition, and functions can give insights into their roles in mediating bacterial survival, pathogenesis, and disease. Furthermore, BMVs can be harnessed to develop cutting-edge nano-therapeutics including targeted chemotherapy delivery, antimicrobials, and novel vaccines. Here we describe routine methods that can be used for small- or large-scale production, isolation, and purification of outer membrane vesicles produced by Gram-negative bacteria, and membrane vesicles produced by Gram-positive bacteria, which we collectively refer to as BMVs. We discuss methods that can be used to visualize BMVs by electron microscopy, and to quantify their DNA, RNA, and protein cargo. We outline a method for the fluorescent labeling of BMVs that can be applied to examine their ability to interact with and enter host cells using a range of in vitro and in vivo biological assays. Finally, we provide a cell culture-based method that can be used to examine a range of immunogenic properties of BMVs, including their cytotoxicity, ability to activate pathogen-recognition receptors (PRRs), induce autophagy and cytokine responses, and modulate cellular pathways.
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Affiliation(s)
- Natalie J Bitto
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia.,Research Centre for Extracellular Vesicles, School of Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Maria Kaparakis-Liaskos
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia. .,Research Centre for Extracellular Vesicles, School of Molecular Sciences, La Trobe University, Melbourne, VIC, Australia.
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5
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Bitto NJ, Cheng L, Johnston EL, Pathirana R, Phan TK, Poon IKH, O'Brien-Simpson NM, Hill AF, Stinear TP, Kaparakis-Liaskos M. Staphylococcus aureus membrane vesicles contain immunostimulatory DNA, RNA and peptidoglycan that activate innate immune receptors and induce autophagy. J Extracell Vesicles 2021; 10:e12080. [PMID: 33815695 PMCID: PMC8015888 DOI: 10.1002/jev2.12080] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 02/12/2021] [Accepted: 03/04/2021] [Indexed: 12/14/2022] Open
Abstract
Gram‐positive bacteria ubiquitously produce membrane vesicles (MVs), and although they contribute to biological functions, our knowledge regarding their composition and immunogenicity remains limited. Here we examine the morphology, contents and immunostimulatory functions of MVs produced by three Staphylococcus aureus strains; a methicillin resistant clinical isolate, a methicillin sensitive clinical isolate and a laboratory‐adapted strain. We observed differences in the number and morphology of MVs produced by each strain and showed that they contain microbe‐associated molecular patterns (MAMPs) including protein, nucleic acids and peptidoglycan. Analysis of MV‐derived RNA indicated the presence of small RNA (sRNA). Furthermore, we detected variability in the amount and composition of protein, nucleic acid and peptidoglycan cargo carried by MVs from each S. aureus strain. S. aureus MVs activated Toll‐like receptor (TLR) 2, 7, 8, 9 and nucleotide‐binding oligomerization domain containing protein 2 (NOD2) signalling and promoted cytokine and chemokine release by epithelial cells, thus identifying that MV‐associated MAMPs including DNA, RNA and peptidoglycan are detected by pattern recognition receptors (PRRs). Moreover, S. aureus MVs induced the formation of and colocalized with autophagosomes in epithelial cells, while inhibition of lysosomal acidification using bafilomycin A1 resulted in accumulation of autophagosomal puncta that colocalized with MVs, revealing the ability of the host to degrade MVs via autophagy. This study reveals the ability of DNA, RNA and peptidoglycan associated with MVs to activate PRRs in host epithelial cells, and their intracellular degradation via autophagy. These findings advance our understanding of the immunostimulatory roles of Gram‐positive bacterial MVs in mediating pathogenesis, and their intracellular fate within the host.
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Affiliation(s)
- Natalie J Bitto
- Department of Physiology Anatomy and Microbiology La Trobe University Melbourne Victoria 3086 Australia.,Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia
| | - Lesley Cheng
- Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Ella L Johnston
- Department of Physiology Anatomy and Microbiology La Trobe University Melbourne Victoria 3086 Australia.,Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia
| | - Rishi Pathirana
- Department of Physiology Anatomy and Microbiology La Trobe University Melbourne Victoria 3086 Australia.,Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia
| | - Thanh Kha Phan
- Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Ivan K H Poon
- Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Neil M O'Brien-Simpson
- Centre for Oral Health Research Melbourne Dental School Bio21 Institute The University of Melbourne Parkville Victoria 3010 Australia
| | - Andrew F Hill
- Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology Doherty Institute University of Melbourne Parkville Victoria 3010 Australia
| | - Maria Kaparakis-Liaskos
- Department of Physiology Anatomy and Microbiology La Trobe University Melbourne Victoria 3086 Australia.,Research Centre for Extracellular Vesicles School of Molecular Sciences La Trobe University Melbourne Victoria 3086 Australia
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6
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Gilmore WJ, Johnston EL, Zavan L, Bitto NJ, Kaparakis-Liaskos M. Immunomodulatory roles and novel applications of bacterial membrane vesicles. Mol Immunol 2021; 134:72-85. [PMID: 33725501 DOI: 10.1016/j.molimm.2021.02.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 12/19/2022]
Abstract
Bacteria release extracellular vesicles (EVs) known as bacterial membrane vesicles (BMVs) during their normal growth. Gram-negative bacteria produce BMVs termed outer membrane vesicles (OMVs) that are composed of a range of biological cargo and facilitate numerous bacterial functions, including promoting pathogenesis and mediating disease in the host. By contrast, less is understood about BMVs produced by Gram-positive bacteria, which are referred to as membrane vesicles (MVs), however their contribution to mediating bacterial pathogenesis has recently become evident. In this review, we summarise the mechanisms whereby BMVs released by Gram-negative and Gram-positive bacteria are produced, in addition to discussing their key functions in promoting bacterial survival, mediating pathogenesis and modulating host immune responses. Furthermore, we discuss the mechanisms whereby BMVs produced by both commensal and pathogenic organisms can enter host cells and interact with innate immune receptors, in addition to how they modulate host innate and adaptive immunity to promote immunotolerance or drive the onset and progression of disease. Finally, we highlight current and emerging applications of BMVs in vaccine design, biotechnology and cancer therapeutics.
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Affiliation(s)
- William J Gilmore
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia; Research Centre for Extracellular Vesicles, School of Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Ella L Johnston
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia; Research Centre for Extracellular Vesicles, School of Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Lauren Zavan
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia; Research Centre for Extracellular Vesicles, School of Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Natalie J Bitto
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia; Research Centre for Extracellular Vesicles, School of Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Maria Kaparakis-Liaskos
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia; Research Centre for Extracellular Vesicles, School of Molecular Science, La Trobe University, Melbourne, VIC, Australia.
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7
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Abstract
The release of extracellular vesicles (EVs) is a process conserved across the three domains of life. Amongst prokaryotes, EVs produced by Gram-negative bacteria, termed outer membrane vesicles (OMVs), were identified more than 50 years ago and a wealth of literature exists regarding their biogenesis, composition and functions. OMVs have been implicated in benefiting numerous metabolic functions of their parent bacterium. Additionally, OMVs produced by pathogenic bacteria have been reported to contribute to pathology within the disease setting. By contrast, the release of EVs from Gram-positive bacteria, known as membrane vesicles (MVs), has only been widely accepted within the last decade. As such, there is a significant disproportion in knowledge regarding MVs compared to OMVs. Here we provide an overview of the literature regarding bacterial membrane vesicles (BMVs) produced by pathogenic and commensal bacteria. We highlight the mechanisms of BMV biogenesis and their roles in assisting bacterial survival, in addition to discussing their functions in promoting disease pathologies and their potential use as novel therapeutic strategies.
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Affiliation(s)
- William J Gilmore
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
- Research Centre for Extracellular Vesicles, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Natalie J Bitto
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
- Research Centre for Extracellular Vesicles, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Maria Kaparakis-Liaskos
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia.
- Research Centre for Extracellular Vesicles, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia.
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8
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Zavan L, Bitto NJ, Johnston EL, Greening DW, Kaparakis-Liaskos M. Back Cover: Helicobacter pylori
Growth Stage Determines the Size, Protein Composition, and Preferential Cargo Packaging of Outer Membrane Vesicles. Proteomics 2019. [DOI: 10.1002/pmic.201970004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Zavan L, Bitto NJ, Johnston EL, Greening DW, Kaparakis-Liaskos M. Helicobacter pylori Growth Stage Determines the Size, Protein Composition, and Preferential Cargo Packaging of Outer Membrane Vesicles. Proteomics 2018; 19:e1800209. [PMID: 30488570 DOI: 10.1002/pmic.201800209] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/13/2018] [Indexed: 01/27/2023]
Abstract
Gram-negative bacteria release outer membrane vesicles (OMVs) as part of their normal growth that contain a range of cargo from their parent bacterium, including DNA, RNA, and proteins. The protein content of OMVs is suggested to be similar in composition to various sub-cellular locations of their parent bacterium. However, very little is known regarding the effect of bacterial growth stage on the size, content, and selective packaging of proteins into OMVs. In this study, the global proteome of Helicobacter pylori and their OMVs throughout bacterial growth are examined to determine if bacterial growth stage affected OMV cargo composition. Analysis of OMVs produced by H. pylori reveals that bacterial growth stage affects the size, composition, and selection of protein cargo into OMVs. Proteomic analysis identifies that the proteome of H. pylori OMVs is vastly different throughout bacterial growth and that OMVs contain a range of proteins compared to their parent bacteria. In addition, bacterial growth stage affects the ability of OMVs to induce the production of IL-8 by human epithelial cells. Therefore, the findings identify that the size, proteome, and immunogenicity of OMVs produced during various stages of bacterial growth is not comparable. Collectively, these findings highlight the importance of considering the bacterial growth stage from which OMVs are isolated, as this will impact their size, protein composition, and ultimately their biological functions.
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Affiliation(s)
- Lauren Zavan
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Natalie J Bitto
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Ella L Johnston
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, 3086, Australia
| | - David W Greening
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Bundoora, VIC, 3086, Australia.,Research Centre for Extracellular Vesicles, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Maria Kaparakis-Liaskos
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, 3086, Australia.,Research Centre for Extracellular Vesicles, La Trobe University, Bundoora, VIC, 3086, Australia
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10
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Bitto NJ, Baker PJ, Dowling JK, Wray-McCann G, De Paoli A, Tran LS, Leung PL, Stacey KJ, Mansell A, Masters SL, Ferrero RL. Membrane vesicles from Pseudomonas aeruginosa activate the noncanonical inflammasome through caspase-5 in human monocytes. Immunol Cell Biol 2018; 96:1120-1130. [PMID: 30003588 DOI: 10.1111/imcb.12190] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 12/15/2022]
Abstract
Outer membrane vesicles (OMVs) are constitutively produced by Gram-negative bacteria both in vivo and in vitro. These lipid-bound structures carry a range of immunogenic components derived from the parent cell, which are transported into host target cells and activate the innate immune system. Recent advances in the field have shed light on some of the multifaceted roles of OMVs in host-pathogen interactions. In this study, we investigated the ability of OMVs from two clinically important pathogens, Pseudomonas aeruginosa and Helicobacter pylori, to activate canonical and noncanonical inflammasomes. P. aeruginosa OMVs induced inflammasome activation in mouse macrophages, as evidenced by "speck" formation, as well as the cleavage and secretion of interleukin-1β and caspase-1. These responses were independent of AIM2 and NLRC4 canonical inflammasomes, but dependent on the noncanonical caspase-11 pathway. Moreover, P. aeruginosa OMVs alone were able to activate the inflammasome in a TLR-dependent manner, without requiring an exogenous priming signal. In contrast, H. pylori OMVs were not able to induce inflammasome activation in macrophages. Using CRISPR/Cas9 knockout THP-1 cells lacking the human caspase-11 homologs, caspase-4 and -5,we demonstrated that caspase-5 but not caspase-4 is required for inflammasome activation by P. aeruginosa OMVs in human monocytes. In contrast, free P. aeruginosa lipopolysaccharide (LPS) transfected into cells induced inflammasome responses via caspase-4. This suggests that caspase-4 and caspase-5 differentially recognize LPS depending on its physical form or route of delivery into the cell. These findings have relevance to Gram-negative infections in humans and the use of OMVs as novel vaccines.
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Affiliation(s)
- Natalie J Bitto
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia
| | - Paul J Baker
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jennifer K Dowling
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia
| | - Georgie Wray-McCann
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia
| | - Amanda De Paoli
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia
| | - Le Son Tran
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia
| | - Pak Ling Leung
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Katryn J Stacey
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ashley Mansell
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia
| | - Seth L Masters
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Richard L Ferrero
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC, 3168, Australia
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11
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Turner L, Bitto NJ, Steer DL, Lo C, D'Costa K, Ramm G, Shambrook M, Hill AF, Ferrero RL, Kaparakis-Liaskos M. Helicobacter pylori Outer Membrane Vesicle Size Determines Their Mechanisms of Host Cell Entry and Protein Content. Front Immunol 2018; 9:1466. [PMID: 30013553 PMCID: PMC6036113 DOI: 10.3389/fimmu.2018.01466] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/12/2018] [Indexed: 01/26/2023] Open
Abstract
Gram-negative pathogens ubiquitously shed outer membrane vesicles (OMVs) that play a central role in initiating and regulating pathogenesis in the host. Due to their highly inflammatory nature, OMVs are extensively being examined for their role in mediating disease in addition to their applications in innovative vaccines. A key mechanism whereby OMVs mediate inflammation and disease progression is dependent on their ability to enter host cells. Currently, the role of OMV size on determining their mechanism of cellular entry and their protein composition remains unknown. In this study, we examined the mechanisms whereby OMV size regulates their mode of entry into epithelial cells, in addition to their protein cargo and composition. We identified that a heterogeneous sized population of Helicobacter pylori OMVs entered epithelial cells via macropinocytosis, clathrin, and caveolin-dependent endocytosis. However, smaller OMVs ranging from 20 to 100 nm in size preferentially entered host cells via caveolin-mediated endocytosis. Whereas larger OMVs ranging between 90 and 450 nm in size entered host epithelial cells via macropinocytosis and endocytosis. Most importantly, we identified the previously unknown contribution that OMV size has on determining their protein content, as fewer and less diverse bacterial proteins were contained within small OMVs compared to larger OMVs. Collectively, these findings identify the importance of OMV size in determining the mechanisms of OMV entry into host cells, in addition to regulating their protein cargo, composition, and subsequent immunogenicity. These findings have significant implications in broadening our understanding of the bacterial regulation of virulence determinants and immunogenic proteins associated with OMVs, their role in mediating pathogenesis and in refining the design and development of OMV-based vaccines.
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Affiliation(s)
- Lorinda Turner
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Melbourne, VIC, Australia
| | - Natalie J Bitto
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, VIC, Australia.,Research Centre for Extracellular Vesicles, School of Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | | | - Camden Lo
- Monash Micro Imaging, Monash University, Clayton, VIC, Australia
| | - Kimberley D'Costa
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Melbourne, VIC, Australia
| | - Georg Ramm
- Monash Biomedical Proteomics Facility, Monash University, Clayton, VIC, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
| | - Mitch Shambrook
- Research Centre for Extracellular Vesicles, School of Molecular Sciences, La Trobe University, Melbourne, VIC, Australia.,La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Andrew F Hill
- Research Centre for Extracellular Vesicles, School of Molecular Sciences, La Trobe University, Melbourne, VIC, Australia.,La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Richard L Ferrero
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Melbourne, VIC, Australia.,Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Maria Kaparakis-Liaskos
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Melbourne, VIC, Australia.,Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, VIC, Australia.,Research Centre for Extracellular Vesicles, School of Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
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Abstract
The therapeutic potential of extracellular vesicles from eukaryotes has gained strong interest in recent years. However, research into the therapeutic application of their bacterial counterparts, known as bacterial membrane vesicles, is only just beginning to be appreciated. Membrane vesicles (MVs) from both Gram-positive and Gram-negative bacteria offer significant advantages in therapeutic development, including large-scale, cost effective production and ease of molecular manipulation to display foreign antigens. The nanoparticle size of MVs enables their dissemination through numerous tissue types, and their natural immunogenicity and self-adjuvanting capability can be harnessed to induce both cell-mediated and humoral immunity in vaccine design. Moreover, the ability to target MVs to specific tissues through the display of surface receptors raises their potential use as targeted MV-based anti-cancer therapy. This review discusses recent advances in MV research with particular emphasis on exciting new possibilities for the application of MVs in therapeutic design.
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Affiliation(s)
- Natalie J Bitto
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Melbourne, Victoria 3086, Australia.
| | - Maria Kaparakis-Liaskos
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Melbourne, Victoria 3086, Australia.
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Monash University, Melbourne, Victoria 3068, Australia.
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13
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Pinar A, Dowling JK, Bitto NJ, Robertson AAB, Latz E, Stewart CR, Drummond GR, Cooper MA, McAuley JL, Tate MD, Mansell A. PB1-F2 Peptide Derived from Avian Influenza A Virus H7N9 Induces Inflammation via Activation of the NLRP3 Inflammasome. J Biol Chem 2016; 292:826-836. [PMID: 27913620 DOI: 10.1074/jbc.m116.756379] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/29/2016] [Indexed: 12/13/2022] Open
Abstract
The emergence of avian H7N9 influenza A virus in humans with associated high mortality has highlighted the threat of a potential pandemic. Fatal H7N9 infections are characterized by hyperinflammation and increased cellular infiltrates in the lung. Currently there are limited therapies to address the pathologies associated with H7N9 infection and the virulence factors that contribute to these pathologies. We have found that PB1-F2 derived from H7N9 activates the NLRP3 inflammasome and induces lung inflammation and cellular recruitment that is NLRP3-dependent. We have also shown that H7N9 and A/Puerto Rico/H1N1 (PR8)PB1-F2 peptide treatment induces significant mitochondrial reactive oxygen production, which contributes to NLRP3 activation. Importantly, treatment of cells or mice with the specific NLRP3 inhibitor MCC950 significantly reduces IL-1β maturation, lung cellular recruitment, and cytokine production. Together, these results suggest that PB1-F2 from H7N9 avian influenza A virus may be a major contributory factor to disease pathophysiology and excessive inflammation characteristic of clinical infections and that targeting the NLRP3 inflammasome may be an effective means to reduce the inflammatory burden associated with H7N9 infections.
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Affiliation(s)
- Anita Pinar
- From the Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia.,the Departments of Molecular and Translational Sciences and
| | - Jennifer K Dowling
- From the Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia.,the Departments of Molecular and Translational Sciences and
| | - Natalie J Bitto
- From the Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia.,the Departments of Molecular and Translational Sciences and
| | - Avril A B Robertson
- the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4702, Australia
| | - Eicke Latz
- the Institute of Innate Immunity, University Hospital, University of Bonn, Bonn 53127, Germany.,the Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01655.,the German Center for Neurodegenerative Diseases, Bonn 53175, Germany
| | - Cameron R Stewart
- the Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
| | - Grant R Drummond
- Pharmacology, Monash University, Clayton, Victoria 3168, Australia
| | - Matthew A Cooper
- the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4702, Australia
| | - Julie L McAuley
- the Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michelle D Tate
- From the Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia.,the Departments of Molecular and Translational Sciences and
| | - Ashley Mansell
- From the Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia, .,the Departments of Molecular and Translational Sciences and
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14
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Bitto NJ, Graichen FHM, Monahan BJ. Functionality at the end of a fatty acid chain - chemical and biological routes to ω-hydroxylated fatty acids. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/lite.200900055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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