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Feix AS, Tabaie EZ, Singh AN, Wittenberg NJ, Wilson EH, Joachim A. An in-depth exploration of the multifaceted roles of EVs in the context of pathogenic single-cell microorganisms. Microbiol Mol Biol Rev 2024; 88:e0003724. [PMID: 38869292 PMCID: PMC11426017 DOI: 10.1128/mmbr.00037-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024] Open
Abstract
SUMMARYExtracellular vesicles (EVs) have been recognized throughout scientific communities as potential vehicles of intercellular communication in both eukaryotes and prokaryotes, thereby influencing various physiological and pathological functions of both parent and recipient cells. This review provides an in-depth exploration of the multifaceted roles of EVs in the context of bacteria and protozoan parasite EVs, shedding light on their contributions to physiological processes and disease pathogenesis. These studies highlight EVs as a conserved mechanism of cellular communication, which may lead us to important breakthroughs in our understanding of infection, mechanisms of pathogenesis, and as indicators of disease. Furthermore, EVs are involved in host-microbe interactions, offering insights into the strategies employed by bacteria and protozoan parasites to modulate host responses, evade the immune system, and establish infections.
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Affiliation(s)
- Anna Sophia Feix
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Emily Z. Tabaie
- Division of Biomedical Sciences, University of California, Riverside, California, USA
| | - Aarshi N. Singh
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, USA
| | | | - Emma H. Wilson
- Division of Biomedical Sciences, University of California, Riverside, California, USA
| | - Anja Joachim
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
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2
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Zhao G, Wang S, Nie G, Li N. Unlocking the power of nanomedicine: Cell membrane-derived biomimetic cancer nanovaccines for cancer treatment. MED 2024; 5:660-688. [PMID: 38582088 DOI: 10.1016/j.medj.2024.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/26/2024] [Accepted: 03/14/2024] [Indexed: 04/08/2024]
Abstract
Over the past decades, nanomedicine researchers have dedicated their efforts to developing nanoscale platforms capable of more precisely delivering drug payloads to attack tumors. Cancer nanovaccines are exhibiting a distinctive capability in inducing tumor-specific antitumor responses. Nevertheless, there remain numerous challenges that must be addressed for cancer nanovaccines to evoke sufficient therapeutic effects. Cell membrane-derived nanovaccines are an emerging class of cancer vaccines that comprise a synthetic nanoscale core camouflaged by naturally derived cell membranes. The specific cell membrane has a biomimetic nanoformulation with several distinctive abilities, such as immune evasion, enhanced biocompatibility, and tumor targeting, typically associated with a source cell. Here, we discuss the advancements of cell membrane-derived nanovaccines and how these vaccines are used for cancer therapeutics. Translational endeavors are currently in progress, and additional research is also necessary to effectively address crucial areas of demand, thereby facilitating the future successful translation of these emerging vaccine platforms.
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Affiliation(s)
- Guo Zhao
- Clinical Trial Center, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Shuhang Wang
- Clinical Trial Center, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
| | - Guangjun Nie
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100000, China.
| | - Ning Li
- Clinical Trial Center, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
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3
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Brusletto BS, Hellerud BC, Øvstebø R, Brandtzaeg P. Neisseria meningitidis accumulate in large organs during meningococcal sepsis. Front Cell Infect Microbiol 2023; 13:1298360. [PMID: 38089821 PMCID: PMC10713808 DOI: 10.3389/fcimb.2023.1298360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 11/07/2023] [Indexed: 12/18/2023] Open
Abstract
Background Neisseria meningitidis (Nm) is the cause of epidemic meningitis and fulminant meningococcal septicemia. The clinical presentations and outcome of meningococcal septic shock is closely related to the circulating levels of lipopolysaccharides (LPS) and of Neisseria meningitidis DNA (Nm DNA). We have previously explored the distribution of Nm DNA in tissues from large organs of patients dying of meningococcal septic shock and in a porcine meningococcal septic shock model. Objective 1) To explore the feasibility of measuring LPS levels in tissues from the large organs in patients with meningococcal septic shock and in a porcine meningococcal septic shock model. 2) To evaluate the extent of contamination of non-specific LPS during the preparation of tissue samples. Patients and methods Plasma, serum, and fresh frozen (FF) tissue samples from the large organs of three patients with lethal meningococcal septic shock and two patients with lethal pneumococcal disease. Samples from a porcine meningococcal septic shock model were included. Frozen tissue samples were thawed, homogenized, and prepared for quantification of LPS by Pyrochrome® Limulus Amoebocyte Lysate (LAL) assay. Results N. meningitidis DNA and LPS was detected in FF tissue samples from large organs in all patients with meningococcal septic shock. The lungs are the organs with the highest LPS and Nm DNA concentration followed by the heart in two of the three meningococcal shock patients. Nm DNA was not detected in any plasma or tissue sample from patients with lethal pneumococcal infection. LPS was detected at a low level in all FF tissues from the two patients with lethal pneumococcal disease. The experimental porcine meningococcal septic shock model indicates that also in porcinis the highest LPS and Nm DNA concentration are detected in lungs tissue samples. The quantification analysis showed that the highest concentration of both Nm DNA and LPS are in the organs and not in the circulation of patients with lethal meningococcal septic shock. This was also shown in the experimental porcine meningococcal septic shock model. Conclusion Our results suggest that LPS can be quantified in mammalian tissues by using the LAL assay.
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Affiliation(s)
| | | | - Reidun Øvstebø
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Petter Brandtzaeg
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Pediatrics, Oslo University Hospital, Nydalen, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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4
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McMillan HM, Kuehn MJ. Proteomic Profiling Reveals Distinct Bacterial Extracellular Vesicle Subpopulations with Possibly Unique Functionality. Appl Environ Microbiol 2023; 89:e0168622. [PMID: 36533919 PMCID: PMC9888257 DOI: 10.1128/aem.01686-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 12/23/2022] Open
Abstract
Bacterial outer membrane vesicles (OMVs) are 20- to 200-nm secreted packages of lipids, small molecules, and proteins that contribute to diverse bacterial processes. In plant systems, OMVs from pathogenic and beneficial strains elicit plant immune responses that inhibit seedling growth and protect against future pathogen challenge. Previous studies of OMV-plant interactions suggest functionally important differences in the protein composition of Pseudomonas syringae and Pseudomonas fluorescens OMVs, and that their composition and activity differ as a result of medium culture conditions. Here, we show that plant apoplast-mimicking minimal medium conditions impact OMV protein content dramatically in P. syringae but not in P. fluorescens relative to complete medium conditions. Comparative, 2-way analysis of the four conditions reveals subsets of proteins that may contribute to OMV-mediated bacterial virulence and plant immune activation as well as those involved in bacterial stress tolerance or adaptation to a beneficial relationship with plants. Additional localization enrichment analysis of these subsets suggests the presence of outer-inner membrane vesicles (OIMVs). Collectively, these results reveal distinct differences in bacterial extracellular vesicle cargo and biogenesis routes from pathogenic and beneficial plant bacteria in different medium conditions and point to distinct populations of vesicles with diverse functional roles. IMPORTANCE Recent publications have shown that bacterial vesicles play important roles in interkingdom communication between bacteria and plants. Indeed, our recently published data reveal that bacterial vesicles from pathogenic and beneficial strains elicit immune responses in plants that protect against future pathogen challenge. However, the molecules underlying these striking phenomena remain unknown. Our recent work indicated that proteins packaged in vesicles are critically important for vesicle-mediated seedling growth inhibition, often considered an indirect measure of plant immune activation. In this study, we characterize the protein cargo of vesicles from Pseudomonas syringae pathovar tomato DC3000 and Pseudomonas fluorescens from two different medium conditions and show that distinct subpopulations of vesicles contribute to bacterial virulence and stress tolerance. Furthermore, we reveal differences in how beneficial and pathogenic bacterial species respond to harsh environmental conditions through vesicle packaging. Importantly, we find that protein cargo implicates outer-inner membrane vesicles in bacterial stress responses, while outer membrane vesicles are packaged for virulence.
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Affiliation(s)
- Hannah M. McMillan
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Meta J. Kuehn
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
- Department of Biochemistry, Duke University, Durham, North Carolina, USA
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5
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Pirolli NH, Bentley WE, Jay SM. Bacterial Extracellular Vesicles and the Gut-Microbiota Brain Axis: Emerging Roles in Communication and Potential as Therapeutics. Adv Biol (Weinh) 2021; 5:e2000540. [PMID: 33857347 DOI: 10.1002/adbi.202000540] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/24/2021] [Indexed: 12/20/2022]
Abstract
Bacterial extracellular vesicles (BEVs) have emerged as candidate signaling vectors for long-distance interkingdom communication within the gut-microbiota brain axis. Most bacteria release these nanosized vesicles, capable of signaling to the brain via their abundant protein and small RNA cargo, possibly directly via crossing the blood-brain barrier. BEVs have been shown to regulate brain gene expression and induce pathology at most stages of neuroinflammation and neurodegeneration, and thus they may play a causal role in diseases such as Alzheimer's, Parkinson's, and depression/anxiety. On the other hand, BEVs have intrinsic therapeutic properties that may be relevant to probiotic therapy and can also be engineered to function as drug delivery vehicles and vaccines. Thus, BEVs may be both a cause of and solution to neuropathological conditions. In this review, current knowledge of the physiological roles of BEVs as well as state of the art pertaining to the development of therapeutic BEVs in the context of the microbiome-gut-brain axis are summarized.
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Affiliation(s)
- Nicholas H Pirolli
- Fischell Department of Bioengineering, University of Maryland, 3102 A. James Clark Hall, College Park, MD, 20742, USA
| | - William E Bentley
- Fischell Department of Bioengineering, Robert E. Fischell Institute, and Institute for Bioscience and Biotechnology Research, University of Maryland, 5120A A. James Clark Hall, College Park, MD, 20742, USA
| | - Steven M Jay
- Fischell Department of Bioengineering and Program in Molecular and Cell Biology, University of Maryland, 3116 A. James Clark Hall, College Park, MD, 20742, USA
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Outer Membrane Vesicle Production by Helicobacter pylori Represents an Approach for the Delivery of Virulence Factors CagA, VacA and UreA into Human Gastric Adenocarcinoma (AGS) Cells. Int J Mol Sci 2021; 22:ijms22083942. [PMID: 33920443 PMCID: PMC8069053 DOI: 10.3390/ijms22083942] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/07/2021] [Accepted: 04/09/2021] [Indexed: 01/18/2023] Open
Abstract
Helicobacter pylori infection is the etiology of several gastric-related diseases including gastric cancer. Cytotoxin associated gene A (CagA), vacuolating cytotoxin A (VacA) and α-subunit of urease (UreA) are three major virulence factors of H. pylori, and each of them has a distinct entry pathway and pathogenic mechanism during bacterial infection. H. pylori can shed outer membrane vesicles (OMVs). Therefore, it would be interesting to explore the production kinetics of H. pylori OMVs and its connection with the entry of key virulence factors into host cells. Here, we isolated OMVs from H. pylori 26,695 strain and characterized their properties and interaction kinetics with human gastric adenocarcinoma (AGS) cells. We found that the generation of OMVs and the presence of CagA, VacA and UreA in OMVs were a lasting event throughout different phases of bacterial growth. H. pylori OMVs entered AGS cells mainly through macropinocytosis/phagocytosis. Furthermore, CagA, VacA and UreA could enter AGS cells via OMVs and the treatment with H. pylori OMVs would cause cell death. Comparison of H. pylori 26,695 and clinical strains suggested that the production and characteristics of OMVs are not only limited to laboratory strains commonly in use, but a general phenomenon to most H. pylori strains.
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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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Uddin MJ, Dawan J, Jeon G, Yu T, He X, Ahn J. The Role of Bacterial Membrane Vesicles in the Dissemination of Antibiotic Resistance and as Promising Carriers for Therapeutic Agent Delivery. Microorganisms 2020; 8:E670. [PMID: 32380740 PMCID: PMC7284617 DOI: 10.3390/microorganisms8050670] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/25/2020] [Accepted: 05/02/2020] [Indexed: 12/11/2022] Open
Abstract
The rapid emergence and spread of antibiotic-resistant bacteria continues to be an issue difficult to deal with, especially in the clinical, animal husbandry, and food fields. The occurrence of multidrug-resistant bacteria renders treatment with antibiotics ineffective. Therefore, the development of new therapeutic methods is a worthwhile research endeavor in treating infections caused by antibiotic-resistant bacteria. Recently, bacterial membrane vesicles (BMVs) have been investigated as a possible approach to drug delivery and vaccine development. The BMVs are released by both pathogenic and non-pathogenic Gram-positive and Gram-negative bacteria, containing various components originating from the cytoplasm and the cell envelope. The BMVs are able to transform bacteria with genes that encode enzymes such as proteases, glycosidases, and peptidases, resulting in the enhanced antibiotic resistance in bacteria. The BMVs can increase the resistance of bacteria to antibiotics. However, the biogenesis and functions of BMVs are not fully understood in association with the bacterial pathogenesis. Therefore, this review aims to discuss BMV-associated antibiotic resistance and BMV-based therapeutic interventions.
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Affiliation(s)
- Md Jalal Uddin
- Department of Medical Biomaterials Engineering, College of Biomedical Science, Kangwon National University, Chuncheon, Gangwon 24341, Korea; (M.J.U.); (J.D.); (G.J.)
| | - Jirapat Dawan
- Department of Medical Biomaterials Engineering, College of Biomedical Science, Kangwon National University, Chuncheon, Gangwon 24341, Korea; (M.J.U.); (J.D.); (G.J.)
| | - Gibeom Jeon
- Department of Medical Biomaterials Engineering, College of Biomedical Science, Kangwon National University, Chuncheon, Gangwon 24341, Korea; (M.J.U.); (J.D.); (G.J.)
| | - Tao Yu
- Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining 272033, China;
| | - Xinlong He
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Juhee Ahn
- Department of Medical Biomaterials Engineering, College of Biomedical Science, Kangwon National University, Chuncheon, Gangwon 24341, Korea; (M.J.U.); (J.D.); (G.J.)
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9
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Barker JH, Weiss JP. Detecting lipopolysaccharide in the cytosol of mammalian cells: Lessons from MD-2/TLR4. J Leukoc Biol 2019; 106:127-132. [PMID: 30694581 DOI: 10.1002/jlb.3mir1118-434r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/09/2019] [Accepted: 01/12/2019] [Indexed: 12/21/2022] Open
Abstract
Proinflammatory immune responses to Gram-negative bacterial lipopolysaccharides (LPS) are crucial to innate host defenses but can also contribute to pathology. How host cells sensitively detect structural features of LPS was a mystery for years, especially given that a portion of the molecule essential for its potent proinflammatory properties-lipid A-is buried in the bacterial membrane. Studies of responses to extracellular and vacuolar LPS revealed a crucial role for accessory proteins that specifically bind LPS-rich membranes and extract LPS monomers to generate a complex of LPS, MD-2, and TLR4. These insights provided means to understand better both the remarkable host sensitivity to LPS and the means whereby specific LPS structural features are discerned. More recently, the noncanonical inflammasome, consisting of caspases-4/5 in humans and caspase-11 in mice, has been demonstrated to mediate responses to LPS that has reached the host cytosol. Precisely how LPS gains access to cytosolic caspases-and in what form-is not well characterized, and understanding this process will provide crucial insights into how the noncanonical inflammasome is regulated during infection. Herein, we briefly review what is known about LPS detection by cytosolic caspases-4/5/11, focusing on lessons derived from studies of the better-characterized TLR4 system that might direct future mechanistic questions.
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Affiliation(s)
- Jason H Barker
- Inflammation Program and the Departments of Internal Medicine and Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,The Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Jerrold P Weiss
- Inflammation Program and the Departments of Internal Medicine and Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,The Veterans Affairs Medical Center, Iowa City, Iowa, USA
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10
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Francis IP, Lui X, Wetzler LM. Isolation of Naturally Released Gonococcal Outer Membrane Vesicles as Vaccine Antigens. Methods Mol Biol 2019; 1997:121-141. [PMID: 31119622 DOI: 10.1007/978-1-4939-9496-0_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The emergence and spread of fully antimicrobial resistant Neisseria gonorrhoeae (GC) highlights a clear need for next-generation antigonococcal therapeutics. A broadly reactive anti-GC vaccine would best address this global public health threat. Polyantigenic outer membrane vesicles (OMVs) derived from GC can overcome the challenges posed by GC's high rate of phase and antigen variation. In fact, GC OMVs have already shown promise as a vaccine antigen; however, all previous studies have utilized vesicles contaminated by RMP, a bacterioprotective antigen known to entirely abrogate vaccine-induced bactericidal activity in vivo. Additionally, these studies primarily utilized vesicles isolated through techniques like membrane disruption with detergents, which are known to increase contamination of cytoplasmic components as compared to naturally released OMVs (nOMVs). This chapter describes the isolation and characterization of naturally released nOMVs through sequential size and weight restrictive filtration. nOMVs are characterized by morphology, proteomics, and bioactivity via various methods. Herein we also describe methods for further evaluation of the innate and induced immunogenicity of rmp-deficient GC nOMVs by cell stimulation and murine vaccination. Per these methods, nOMVs are found to be largely homogenous spherical structures approximately 70 nm in diameter containing a consistent subset of GC outer membrane proteins. The rmp-deficient vesicles demonstrate a morphology and, with the exception of RMP, antigenic profile consistent with that of nOMVs derived from wild time N. gonorrhoeae. Additionally, vesicles lacking RMP are able to engage and strongly activate a diverse array of pattern recognition receptors in vitro. These methods lay the groundwork for future experiments examining the in vivo protective efficacy of the anti-GC response induced by these nOMVs as well as studies examining the mechanism of vaccine induced female genital tract immunity.
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Affiliation(s)
- Ian P Francis
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center, Boston, MA, USA
| | - Xiuping Lui
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA
| | - Lee M Wetzler
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center, Boston, MA, USA. .,Department of Microbiology, Boston University School of Medicine, Boston, MA, USA.
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11
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Baarda BI, Martinez FG, Sikora AE. Proteomics, Bioinformatics and Structure-Function Antigen Mining For Gonorrhea Vaccines. Front Immunol 2018; 9:2793. [PMID: 30564232 PMCID: PMC6288298 DOI: 10.3389/fimmu.2018.02793] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/13/2018] [Indexed: 12/12/2022] Open
Abstract
Expanding efforts to develop preventive gonorrhea vaccines is critical because of the serious health consequences combined with the prevalence and the dire possibility of untreatable gonorrhea. Reverse vaccinology, which includes genome and proteome mining, has proven successful in the discovery of vaccine candidates against many pathogenic bacteria. Here, we describe proteomic applications including comprehensive, quantitative proteomic platforms and immunoproteomics coupled with broad-ranging bioinformatics that have been applied for antigen mining to develop gonorrhea vaccine(s). We further focus on outlining the vaccine candidate decision tree, describe the structure-function of novel proteome-derived antigens as well as ways to gain insights into their roles in the cell envelope, and underscore new lessons learned about the fascinating biology of Neisseria gonorrhoeae.
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Affiliation(s)
- Benjamin I. Baarda
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, United States
| | - Fabian G. Martinez
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, United States
| | - Aleksandra E. Sikora
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, United States
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, OR, United States
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12
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Zhu W, Tomberg J, Knilans KJ, Anderson JE, McKinnon KP, Sempowski GD, Nicholas RA, Duncan JA. Properly folded and functional PorB from Neisseria gonorrhoeae inhibits dendritic cell stimulation of CD4 + T cell proliferation. J Biol Chem 2018; 293:11218-11229. [PMID: 29752412 DOI: 10.1074/jbc.ra117.001209] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/19/2018] [Indexed: 12/14/2022] Open
Abstract
Neisseria gonorrhoeae is an exclusive human pathogen that evades the host immune system through multiple mechanisms. We have shown that N. gonorrhoeae suppresses the capacity of antigen-presenting cells to induce CD4+ T cell proliferation. In this study, we sought to determine the gonococcal factors involved in this adaptive immune suppression. We show that suppression of the capacity of antigen-pulsed dendritic cells to induce T cell proliferation is recapitulated by administration of a high-molecular-weight fraction of conditioned medium from N. gonorrhoeae cultures, which includes outer membrane vesicles that are shed during growth of the bacteria. N. gonorrhoeae PorB is the most abundant protein in N. gonorrhoeae-derived vesicles, and treatment of dendritic cells with purified recombinant PorB inhibited the capacity of the cells to stimulate T cell proliferation. This immunosuppressive feature of purified PorB depended on proper folding of the protein. PorB from N. gonorrhoeae, as well as other Neisseria species and other Gram-negative bacterial species, are known to activate host Toll-like receptor 2 (TLR2) signaling. Published studies have demonstrated that purified Neisseria PorB forms proteinacious nanoparticles, termed proteosomes, when detergent micelles are removed. Unlike folded, detergent-solubilized PorB, PorB proteosomes stimulate immune responses. We now demonstrate that the formation of PorB proteosomes from structurally intact PorB eliminates the immunosuppressive property of the protein while enhancing TLR2 stimulation. These findings suggest that gonococcal PorB present in shed outer membrane vesicles plays a role in suppression of adaptive immune responses to this immune-evasive pathogen.
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Affiliation(s)
- Weiyan Zhu
- From the Department of Medicine, Division of Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Joshua Tomberg
- the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Kayla J Knilans
- the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - James E Anderson
- From the Department of Medicine, Division of Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Karen P McKinnon
- the Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina 27599, and.,the Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Gregory D Sempowski
- the Department of Medicine and Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina 27710
| | - Robert A Nicholas
- the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, .,the Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina 27599, and
| | - Joseph A Duncan
- From the Department of Medicine, Division of Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina 27599, .,the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599.,the Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599
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13
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Abstract
In humans and other mammals, recognition of endotoxins—abundant surface lipopolysaccharides (LPS) of Gram-negative bacteria—provides a potent stimulus for induction of inflammation and mobilization of host defenses. The structurally unique lipid A region of LPS is the principal determinant of this pro-inflammatory activity. This region of LPS is normally buried within the bacterial outer membrane and aggregates of purified LPS, making even more remarkable its picomolar potency and the ability of discrete variations in lipid A structure to markedly alter the pro-inflammatory activity of LPS. Two recognition systems—MD-2/TLR4 and “LPS-sensing” cytosolic caspases—together confer LPS responsiveness at the host cell surface, within endosomes, and at sites physically accessible to the cytosol. Understanding how the lipid A of LPS is delivered and recognized at these diverse sites is crucial to understanding how the magnitude and character of the inflammatory responses are regulated.
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Affiliation(s)
- Jerrold Weiss
- Inflammation Program and Departments of Internal Medicine and Microbiology, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Jason Barker
- Inflammation Program and Departments of Internal Medicine and Microbiology, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
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14
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Dauros-Singorenko P, Blenkiron C, Phillips A, Swift S. The functional RNA cargo of bacterial membrane vesicles. FEMS Microbiol Lett 2018; 365:4830096. [DOI: 10.1093/femsle/fny023] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/25/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Priscila Dauros-Singorenko
- Department of Molecular Medicine and Pathology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Cherie Blenkiron
- Department of Molecular Medicine and Pathology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Department of Obstetrics and Gynaecology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Anthony Phillips
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Department of Surgery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Simon Swift
- Department of Molecular Medicine and Pathology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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15
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Cochet F, Peri F. The Role of Carbohydrates in the Lipopolysaccharide (LPS)/Toll-Like Receptor 4 (TLR4) Signalling. Int J Mol Sci 2017; 18:E2318. [PMID: 29099761 PMCID: PMC5713287 DOI: 10.3390/ijms18112318] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/27/2017] [Accepted: 10/30/2017] [Indexed: 12/12/2022] Open
Abstract
The interactions between sugar-containing molecules from the bacteria cell wall and pattern recognition receptors (PRR) on the plasma membrane or cytosol of specialized host cells are the first molecular events required for the activation of higher animal's immune response and inflammation. This review focuses on the role of carbohydrates of bacterial endotoxin (lipopolysaccharide, LPS, lipooligosaccharide, LOS, and lipid A), in the interaction with the host Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD-2) complex. The lipid chains and the phosphorylated disaccharide core of lipid A moiety are responsible for the TLR4 agonist action of LPS, and the specific interaction between MD-2, TLR4, and lipid A are key to the formation of the activated complex (TLR4/MD-2/LPS)₂, which starts intracellular signalling leading to nuclear factors activation and to production of inflammatory cytokines. Subtle chemical variations in the lipid and sugar parts of lipid A cause dramatic changes in endotoxin activity and are also responsible for the switch from TLR4 agonism to antagonism. While the lipid A pharmacophore has been studied in detail and its structure-activity relationship is known, the contribution of core saccharides 3-deoxy-d-manno-octulosonic acid (Kdo) and heptosyl-2-keto-3-deoxy-octulosonate (Hep) to TLR4/MD-2 binding and activation by LPS and LOS has been investigated less extensively. This review focuses on the role of lipid A, but also of Kdo and Hep sugars in LPS/TLR4 signalling.
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Affiliation(s)
- Florent Cochet
- Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Francesco Peri
- Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
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16
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Abstract
Bacterial membrane vesicles (BMVs) are closed spherical nanostructures that are shed naturally and ubiquitously by most bacterial species both in vivo and in vitro. Researchers have elucidated their roles in long-distance transport of a wide array of cargoes, such as proteins, toxins, antigens, virulence factors, microbicidal agents and antibiotics. Given that these natural carriers are important players in intercellular communication, it has been hypothesized that they are equally well attuned for transport and delivery of exogenous therapeutic cargoes. Additionally, BMVs appear to possess specific properties that enable their utilization as drug delivery vehicles. These include their ability to evade the host immune system, protection of the therapeutic payload and natural stability. Using bioengineering approaches, BMVs have been applied as carriers of therapeutic moieties in vaccines and for targeted delivery in cancer. In this article, we explore BMVs from the perspective of understanding their applicability to drug delivery. BMV biology, including biogenesis, physiology and pathology, is briefly reviewed. Practical issues related to bioprocessing, loading of therapeutic moieties and characterization for enabling scalability and commercial viability are evaluated. Finally, challenges to clinical translation and rational design approaches for novel BMV formulations are presented. Although the realization of the full potential of BMVs in drug delivery hinges on the development of scalable approaches for their production as well as the refinement of targeting and loading methods, they are promising candidates for development of a novel generation of drug delivery vehicles in future.
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Affiliation(s)
- Sapna Jain
- Implants, Devices and Drug Delivery Systems Laboratory, Centre for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Faridabad, Haryana, India
| | - Jonathan Pillai
- Implants, Devices and Drug Delivery Systems Laboratory, Centre for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Faridabad, Haryana, India
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17
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Dauros Singorenko P, Chang V, Whitcombe A, Simonov D, Hong J, Phillips A, Swift S, Blenkiron C. Isolation of membrane vesicles from prokaryotes: a technical and biological comparison reveals heterogeneity. J Extracell Vesicles 2017; 6:1324731. [PMID: 28717421 PMCID: PMC5505020 DOI: 10.1080/20013078.2017.1324731] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Indexed: 01/07/2023] Open
Abstract
Prokaryotes release membrane vesicles (MVs) with direct roles in disease pathogenesis. MVs are heterogeneous when isolated from bacterial cultures so Density Gradient Centrifugation (DGC) is valuable for separation of MV subgroups from contaminating material. Here we report the technical variability and natural biological heterogeneity seen between DGC preparations of MVs for Mycobacterium smegmatis and Escherichia coli and compare these DGC data with size exclusion chromatography (SEC) columns. Crude preparations of MVs, isolated from cultures by ultrafiltration and ultracentrifugation were separated by DGC with fractions manually collected as guided by visible bands. Yields of protein, RNA and endotoxin, protein banding and particle counts were analysed in these. DGC and SEC methods enabled separation of molecularly distinct MV populations from crude MVs. DGC banding profiles were unique for each of the two species of bacteria tested and further altered by changing culture conditions, for example with iron supplementation. SEC is time efficient, reproducible and cost effective method that may also allow partial LPS removal from Gram-negative bacterial MVs. In summary, both DGC and SEC are suitable for the separation of mixed populations of MVs and we advise trials of both, coupled with complete molecular and single vesicle characterisation prior to downstream experimentation.
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Affiliation(s)
- Priscila Dauros Singorenko
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand.,School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Vanessa Chang
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Alana Whitcombe
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Denis Simonov
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Jiwon Hong
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Anthony Phillips
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand.,School of Biological Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Simon Swift
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Cherie Blenkiron
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand.,School of Biological Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
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18
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Hoppe Parr KA, Hađina S, Kilburg-Basnyat B, Wang Y, Chavez D, Thorne PS, Weiss JP. Modification of sample processing for the Limulus amebocyte lysate assay enhances detection of inflammogenic endotoxin in intact bacteria and organic dust. Innate Immun 2017; 23:307-318. [PMID: 28359219 PMCID: PMC5814115 DOI: 10.1177/1753425917694084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The pro-inflammatory potency and causal relationship with asthma of inhaled endotoxins have underscored the importance of accurately assessing the endotoxin content of organic dusts. The Limulus amebocyte lysate (LAL) assay has emerged as the preferred assay, but its ability to measure endotoxin in intact bacteria and organic dusts with similar sensitivity as purified endotoxin is unknown. We used metabolically radiolabeled Neisseria meningitidis and both rough and smooth Escherichia coli to compare dose-dependent activation in the LAL with purified endotoxin from these bacteria and shed outer membrane (OM) blebs. Labeled [14C]-3-OH-fatty acids were used to quantify the endotoxin content of the samples. Purified meningococcal and E. coli endotoxins and OM blebs displayed similar specific activity in the LAL assay to the purified LPS standard. In contrast, intact bacteria exhibited fivefold lower specific activity in the LAL assay but showed similar MD-2-dependent potency as purified endotoxin in inducing acute airway inflammation in mice. Pre-treatment of intact bacteria and organic dusts with 0.1 M Tris-HCl/10 mM EDTA increased by fivefold the release of endotoxin. These findings demonstrate that house dust and other organic dusts should be extracted with Tris/EDTA to more accurately assess the endotoxin content and pro-inflammatory potential of these environmental samples.
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Affiliation(s)
- Kimberly A. Hoppe Parr
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Suzana Hađina
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Brita Kilburg-Basnyat
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Yifang Wang
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Dulce Chavez
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Peter S. Thorne
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Jerrold P. Weiss
- Departments of Internal Medicine and Microbiology and Inflammation Program, The University of Iowa, Iowa City, IA 52242, USA
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19
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Wacker MA, Teghanemt A, Weiss JP, Barker JH. High-affinity caspase-4 binding to LPS presented as high molecular mass aggregates or in outer membrane vesicles. Innate Immun 2017; 23:336-344. [PMID: 28409545 DOI: 10.1177/1753425917695446] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Caspases of the non-canonical inflammasome (caspases -4, -5, and -11) directly bind endotoxin (LOS/LPS) and can be activated in the absence of any co-factors. Models of LPS-induced caspase activation have postulated that 1:1 binding of endotoxin monomers to caspase trigger caspase oligomerization and activation, analogous to that established for endotoxin-induced activation of MD-2/TLR4. However, using metabolically radiolabeled LOS and LPS, we now show high affinity and selective binding of caspase-4 to high molecular mass aggregates of purified endotoxin and to endotoxin-rich outer membrane vesicles without formation of 1:1 endotoxin:caspase complexes. Thus, our findings demonstrate markedly different endotoxin recognition properties of caspase-4 from that of MD-2/TLR4 and strongly suggest that activation of caspase-4 (and presumably caspase-5 and caspase-11) are mediated by interactions with activating endotoxin-rich membrane interfaces rather than by endotoxin monomers.
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Affiliation(s)
- Mark A Wacker
- 1 Department of Biology, Central Michigan University, Mt. Pleasant, MI, USA
| | - Athmane Teghanemt
- 2 Inflammation Program, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,3 Department of Internal Medicine, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA
| | - Jerrold P Weiss
- 2 Inflammation Program, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,3 Department of Internal Medicine, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,4 Department of Microbiology, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA
| | - Jason H Barker
- 2 Inflammation Program, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,3 Department of Internal Medicine, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,4 Department of Microbiology, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA
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20
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Lee J, Kim OY, Gho YS. Proteomic profiling of Gram-negative bacterial outer membrane vesicles: Current perspectives. Proteomics Clin Appl 2016; 10:897-909. [PMID: 27480505 DOI: 10.1002/prca.201600032] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 06/30/2016] [Accepted: 07/29/2016] [Indexed: 12/18/2022]
Abstract
Outer membrane vesicles (OMVs) are extracellular vesicles derived from Gram-negative bacteria. Recent progress in the studies of Gram-negative bacterial extracellular vesicles implies that OMVs may function as intercellular communicasomes in bacteria-bacteria and bacteria-host interactions. Current MS-based high-throughput proteomic analyses of Gram-negative bacterial OMVs have identified thousands of vesicular proteins and provided clues to reveal the biogenesis and pathophysiological functions of Gram-negative bacterial OMVs. The future directions of proteomics of Gram-negative bacterial OMVs may include the isolation strategy of Gram-negative bacterial OMVs to thoroughly exclude nonvesicular contaminants and proteomics of Gram-negative bacterial OMVs derived from diverse conditions as well as body fluids of bacterium-infected hosts. We hope this review will shed light on future research in this emerging field of proteomics of extracellular vesicles derived from Gram-negative bacteria and contribute to the development of OMV-based diagnostic tools and effective vaccines.
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Affiliation(s)
- Jaewook Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Oh Youn Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Yong Song Gho
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea.
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21
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Vaccine Potential and Diversity of the Putative Cell Binding Factor (CBF, NMB0345/NEIS1825) Protein of Neisseria meningitidis. PLoS One 2016; 11:e0160403. [PMID: 27505005 PMCID: PMC4978444 DOI: 10.1371/journal.pone.0160403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 07/19/2016] [Indexed: 01/01/2023] Open
Abstract
The cbf gene from Neisseria meningitidis strain MC58 encoding the putative Cell Binding Factor (CBF, NMB0345/NEIS1825) protein was cloned into the pRSETA system and a ~36-kDa recombinant (r)CBF protein expressed in Escherichia coli and purified by metal affinity chromatography. High titres of rCBF antibodies were induced in mice following immunization with rCBF-saline, rCBF-Al(OH)3, rCBF-Liposomes or rCBF-Zwittergent (Zw) 3-14 micelles, both with and without incorporated monophosphoryl lipid A (MPLA) adjuvant. Anti-rCBF sera reacted in western blots of meningococcal lysates with a single protein band of molecular mass ~29.5 kDa, indicative of mature CBF protein, but did not react with a lysate of a Δnmb0345 mutant (CBF-), demonstrating specificity of the murine immune responses. CBF protein was produced by all strains of meningococci studied thus far and the protein was present on the surface of MC58 (CBF+) bacteria, but absent on Δnmb0345 mutant (CBF-) bacteria, as judged by FACS reactivity of anti-rCBF sera. Analysis of the NEIS1825 amino acid sequences from 6644 N. meningitidis isolates with defined Alleles in the pubmlst.org/Neisseria database showed that there were 141 ST types represented and there were 136 different allelic loci encoding 49 non-redundant protein sequences. Only 6/6644 (<0.1%) of N. meningitidis isolates lacked the nmb0345 gene. Amongst serogroup B isolates worldwide, ~68% and ~20% expressed CBF encoded by Allele 1 and 18 respectively, with the proteins sharing >99% amino acid identity. Murine antisera to rCBF in Zw 3-14 micelles + MPLA induced significant serum bactericidal activity (SBA) against homologous Allele 1 and heterologous Allele 18 strains, using both baby rabbit serum complement and human serum complement (h)SBA assays, but did not kill strains expressing heterologous protein encoded by Alelle 2 or 3. Furthermore, variable bactericidal activity was induced by murine antisera against different meningococcal strains in the hSBA assay, which may correlate with variable surface exposure of CBF. Regardless, the attributes of amino acid sequence conservation and protein expression amongst different strains and the ability to induce cross-strain bactericidal antibodies indicates that rCBF could be a potential meningococcal vaccine antigen and merits further testing.
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22
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Kaur G, Singh S, Sunil Kumar BV, Mahajan K, Verma R. Characterization and Immunogenicity of Outer Membrane Vesicles fromBrucella abortus. J Immunoassay Immunochem 2015; 37:261-72. [DOI: 10.1080/15321819.2015.1132231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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23
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van der Pol L, Stork M, van der Ley P. Outer membrane vesicles as platform vaccine technology. Biotechnol J 2015; 10:1689-706. [PMID: 26912077 PMCID: PMC4768646 DOI: 10.1002/biot.201400395] [Citation(s) in RCA: 248] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 08/13/2015] [Accepted: 09/24/2015] [Indexed: 12/31/2022]
Abstract
Outer membrane vesicles (OMVs) are released spontaneously during growth by many Gram-negative bacteria. They present a range of surface antigens in a native conformation and have natural properties like immunogenicity, self-adjuvation and uptake by immune cells which make them attractive for application as vaccines against pathogenic bacteria. In particular with Neisseria meningitidis, they have been investigated extensively and an OMV-containing meningococcal vaccine has recently been approved by regulatory agencies. Genetic engineering of the OMV-producing bacteria can be used to improve and expand their usefulness as vaccines. Recent work on meningitis B vaccines shows that OMVs can be modified, such as for lipopolysaccharide reactogenicity, to yield an OMV product that is safe and effective. The overexpression of crucial antigens or simultaneous expression of multiple antigenic variants as well as the expression of heterologous antigens enable expansion of their range of applications. In addition, modifications may increase the yield of OMV production and can be combined with specific production processes to obtain high amounts of well-defined, stable and uniform OMV particle vaccine products. Further improvement can facilitate the development of OMVs as platform vaccine product for multiple applications.
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Affiliation(s)
| | - Michiel Stork
- Product Development, Intravacc, Bilthoven, The Netherlands
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24
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Hung MC, Humbert MV, Laver JR, Phillips R, Heckels JE, Christodoulides M. A putative amino acid ABC transporter substrate-binding protein, NMB1612, from Neisseria meningitidis, induces murine bactericidal antibodies against meningococci expressing heterologous NMB1612 proteins. Vaccine 2015. [PMID: 26207592 DOI: 10.1016/j.vaccine.2015.07.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The nmb1612 (NEIS1533) gene encoding the ~27-kDa putative amino acid ATP-binding cassette (ABC) transporter, periplasmic substrate-binding protein from Neisseria meningitidis serogroup B (MenB) strain MC58 was cloned and expressed in Escherichia coli, and the purified recombinant (r)NMB1612 was used for animal immunization studies. Immunization of mice with rNMB1612 adsorbed to Al(OH)3 and in liposomes with and without MPLA, induced antiserum with bactericidal activity in an assay using baby rabbit complement, against the homologous strain MC58 (encoding protein representative of Allele 62) and killed heterologous strains encoding proteins of three other alleles (representative of Alleles 1, 64 and 68), with similar SBA titres. However, strain MC58 was not killed (titre <4) in a human serum bactericidal assay (hSBA) using anti-rNMB1612 sera, although another strain (MC168) expressing the same protein was killed (median titres of 16-64 in the hSBA). Analysis of the NMB1612 amino acid sequences from 4351 meningococcal strains in the pubmlst.org/Neisseria database and a collection of 13 isolates from colonized individuals and from patients, showed that antibodies raised against rNMB1612 could potentially kill at least 72% of the MenB strains in the complete sequence database. For MenB disease occurring specifically in the UK from 2013 to 2015, >91% of the isolates causing disease in this recent period expressed NMB1612 protein encoded by Allele 1 and could be potentially killed by sera raised to the recombinant antigen in the current study. The NMB1612 protein was surface-accessible and expressed by different meningococcal strains. In summary, the properties of (i) NMB1612 protein conservation and expression, (ii) limited amino acid sequence variation between proteins encoded by different alleles, and (iii) the ability of a recombinant protein to induce cross-strain bactericidal antibodies, would all suggest a promising antigen for consideration for inclusion in new meningococcal vaccines.
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Affiliation(s)
- Miao-Chiu Hung
- Neisseria Research, Molecular Microbiology, Division of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Medical School, Southampton SO166YD, United Kingdom
| | - María Victoria Humbert
- Neisseria Research, Molecular Microbiology, Division of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Medical School, Southampton SO166YD, United Kingdom
| | - Jay R Laver
- Neisseria Research, Molecular Microbiology, Division of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Medical School, Southampton SO166YD, United Kingdom
| | - Renee Phillips
- Neisseria Research, Molecular Microbiology, Division of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Medical School, Southampton SO166YD, United Kingdom
| | - John E Heckels
- Neisseria Research, Molecular Microbiology, Division of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Medical School, Southampton SO166YD, United Kingdom
| | - Myron Christodoulides
- Neisseria Research, Molecular Microbiology, Division of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Medical School, Southampton SO166YD, United Kingdom.
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25
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Weiss JP. Molecular determinants of bacterial sensitivity and resistance to mammalian Group IIA phospholipase A2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3072-7. [PMID: 26079797 DOI: 10.1016/j.bbamem.2015.05.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/18/2015] [Accepted: 05/20/2015] [Indexed: 11/25/2022]
Abstract
Group IIA secretory phospholipase A2 (sPLA(2)-IIA) of mammalian species is unique among the many structurally and functionally related mammalian sPLA(2) in their high net positive charge and potent (nM) antibacterial activity. Toward the Gram-positive bacteria tested thus far, the global cationic properties of sPLA(2)-IIA are necessary for optimal binding to intact bacteria and penetration of the multi-layered thick cell wall, but not for the degradation of membrane phospholipids that is essential for bacterial killing. Various Gram-positive bacterial species can differ as much as 1000-fold in sPLA(2)-IIA sensitivity despite similar intrinsic enzymatic activity of sPLA(2)-IIA toward the membrane phospholipids of various bacteria. d-alanylation of wall- and lipo-teichoic acids in Staphylococcus aureus and sortase function in Streptococcus pyogenes increase bacterial resistance to sPLA(2)-IIA by up to 100-fold apparently by affecting translocation of bound sPLA(2)-IIA to the cell membrane. Action of the sPLA(2)-IIA and other related sPLA(2) against Gram-negative bacteria is more dependent on cationic properties of the enzyme near the amino-terminus of the protein and collaboration with other host defense proteins that produce alterations of the unique Gram-negative bacterial outer membrane that normally represents a barrier to sPLA(2)-IIA action. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.
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Affiliation(s)
- Jerrold P Weiss
- The Inflammation Program, University of Iowa, Iowa City, IA 52242, USA; Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA; Veterans Administration Medical Center, Iowa City, IA 52246, USA.
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26
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Fulsundar S, Kulkarni HM, Jagannadham MV, Nair R, Keerthi S, Sant P, Pardesi K, Bellare J, Chopade BA. Molecular characterization of outer membrane vesicles released from Acinetobacter radioresistens and their potential roles in pathogenesis. Microb Pathog 2015; 83-84:12-22. [PMID: 25940676 DOI: 10.1016/j.micpath.2015.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 10/23/2022]
Abstract
Acinetobacter radioresistens is an important member of genus Acinetobacter from a clinical point of view. In the present study, we report that a clinical isolate of A. radioresistens releases outer membrane vesicles (OMVs) under in vitro growth conditions. OMVs were released in distinctive size ranges with diameters from 10 to 150 nm as measured by the dynamic light scattering (DLS) technique. Additionally, proteins associated with or present into OMVs were identified using LC-ESI-MS/MS. A total of 71 proteins derived from cytosolic, cell membrane, periplasmic space, outer membrane (OM), extracellular and undetermined locations were found in OMVs. The initial characterization of the OMV proteome revealed a correlation of some proteins to biofilm, quorum sensing, oxidative stress tolerance, and cytotoxicity functions. Thus, the OMVs of A. radioresistens are suggested to play a role in biofilm augmentation and virulence possibly by inducing apoptosis.
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Affiliation(s)
- Shweta Fulsundar
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune 411007, India
| | | | | | - Rashmi Nair
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune 411007, India
| | - Sravani Keerthi
- Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Pooja Sant
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune 411007, India
| | - Karishma Pardesi
- Department of Microbiology, Savitribai Phule Pune University, Pune 411007, India
| | - Jayesh Bellare
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Balu Ananda Chopade
- Department of Microbiology, Savitribai Phule Pune University, Pune 411007, India; Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431 004, India.
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27
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Gioannini TL, Teghanemt A, Zhang D, Esparza G, Yu L, Weiss J. Purified monomeric ligand.MD-2 complexes reveal molecular and structural requirements for activation and antagonism of TLR4 by Gram-negative bacterial endotoxins. Immunol Res 2015; 59:3-11. [PMID: 24895101 DOI: 10.1007/s12026-014-8543-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A major focus of work in our laboratory concerns the molecular mechanisms and structural bases of Gram-negative bacterial endotoxin recognition by host (e.g., human) endotoxin-recognition proteins that mediate and/or regulate activation of Toll-like receptor (TLR) 4. Here, we review studies of wild-type and variant monomeric endotoxin.MD-2 complexes first produced and characterized in our laboratories. These purified complexes have provided unique experimental reagents, revealing both quantitative and qualitative determinants of TLR4 activation and antagonism. This review is dedicated to the memory of Dr. Theresa L. Gioannini (1949-2014) who played a central role in many of the studies and discoveries that are reviewed.
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Affiliation(s)
- Theresa L Gioannini
- The Inflammation Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2501 Crosspark Rd, Coralville, IA, 52241, USA
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28
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Kim JH, Lee J, Park J, Gho YS. Gram-negative and Gram-positive bacterial extracellular vesicles. Semin Cell Dev Biol 2015; 40:97-104. [PMID: 25704309 DOI: 10.1016/j.semcdb.2015.02.006] [Citation(s) in RCA: 278] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 02/06/2015] [Accepted: 02/12/2015] [Indexed: 01/26/2023]
Abstract
Like mammalian cells, Gram-negative and Gram-positive bacteria release nano-sized membrane vesicles into the extracellular environment either in a constitutive manner or in a regulated manner. These bacterial extracellular vesicles are spherical bilayered proteolipids enriched with bioactive proteins, lipids, nucleic acids, and virulence factors. Recent progress in this field supports the critical pathophysiological functions of these vesicles in both bacteria-bacteria and bacteria-host interactions. This review provides an overview of the current understanding on Gram-negative and Gram-positive bacterial extracellular vesicles, especially regarding the biogenesis, components, and functions in poly-species communities. We hope that this review will stimulate additional research in this emerging field of bacterial extracellular vesicles and contribute to the development of extracellular vesicle-based diagnostic tools and effective vaccines against pathogenic Gram-negative and Gram-positive bacteria.
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Affiliation(s)
- Ji Hyun Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Jaewook Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Jaesung Park
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Yong Song Gho
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.
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29
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Methods of isolation and purification of outer membrane vesicles from gram-negative bacteria. Microbiol Res 2015; 170:1-9. [DOI: 10.1016/j.micres.2014.09.006] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 09/08/2014] [Accepted: 09/24/2014] [Indexed: 01/31/2023]
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30
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Roier S, Blume T, Klug L, Wagner GE, Elhenawy W, Zangger K, Prassl R, Reidl J, Daum G, Feldman MF, Schild S. A basis for vaccine development: Comparative characterization of Haemophilus influenzae outer membrane vesicles. Int J Med Microbiol 2014; 305:298-309. [PMID: 25592265 DOI: 10.1016/j.ijmm.2014.12.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 12/09/2014] [Accepted: 12/14/2014] [Indexed: 11/29/2022] Open
Abstract
Outer membrane vesicles (OMVs) are spherical and bilayered particles that are naturally released from the outer membrane (OM) of Gram-negative bacteria. They have been proposed to possess several biological roles in pathogenesis and interbacterial interactions. Additionally, OMVs have been suggested as potential vaccine candidates against infections caused by pathogenic bacteria like Haemophilus influenzae, a human pathogen of the respiratory tract. Unfortunately, there is still a lack of fundamental knowledge regarding OMV biogenesis, protein sorting into OMVs, OMV size and quantity, as well as OMV composition in H. influenzae. Thus, this study comprehensively characterized and compared OMVs and OMs derived from heterologous encapsulated as well as nonencapsulated H. influenzae strains. Semiquantitative immunoblot analysis revealed that certain OM proteins are enriched or excluded in OMVs suggesting the presence of regulated protein sorting mechanisms into OMVs as well as interconnected OMV biogenesis mechanisms in H. influenzae. Nanoparticle tracking analysis, transmission electron microscopy, as well as protein and lipooligosaccharide quantifications demonstrated that heterologous H. influenzae strains differ in their OMV size and quantity. Lipidomic analyses identified palmitic acid as the most abundant fatty acid, while phosphatidylethanolamine was found to be the most dominant phospholipid present in OMVs and the OM of all strains tested. Proteomic analysis confirmed that H. influenzae OMVs contain vaccine candidate proteins as well as important virulence factors. These findings contribute to the understanding of OMV biogenesis as well as biological roles of OMVs and, in addition, may be important for the future development of OMV based vaccines against H. influenzae infections.
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Affiliation(s)
- Sandro Roier
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria
| | - Thomas Blume
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria
| | - Lisa Klug
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, BioTechMed-Graz, Petersgasse 12/2, A-8010 Graz, Austria
| | - Gabriel E Wagner
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed-Graz, Heinrichstraße 28, A-8010 Graz, Austria
| | - Wael Elhenawy
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, CW405 Biological Sciences Building, Edmonton, AB, Canada T6G 2E9
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed-Graz, Heinrichstraße 28, A-8010 Graz, Austria
| | - Ruth Prassl
- Institute of Biophysics, Medical University of Graz, BioTechMed-Graz, Harrachgasse 21, A-8010 Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, BioTechMed-Graz, Petersgasse 12/2, A-8010 Graz, Austria
| | - Mario F Feldman
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, CW405 Biological Sciences Building, Edmonton, AB, Canada T6G 2E9
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria.
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31
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Kulkarni HM, Jagannadham MV. Biogenesis and multifaceted roles of outer membrane vesicles from Gram-negative bacteria. Microbiology (Reading) 2014; 160:2109-2121. [DOI: 10.1099/mic.0.079400-0] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Outer membrane vesicles (OMVs) released from Gram-negative bacteria consist of lipids, proteins, lipopolysaccharides and other molecules. OMVs are associated with several biological functions such as horizontal gene transfer, intracellular and intercellular communication, transfer of contents to host cells, and eliciting an immune response in host cells. Although hypotheses have been made concerning the mechanism of biogenesis of these vesicles, research on OMV formation is far from complete. The roles of outer membrane components, bacterial quorum sensing molecules and some specific proteins in OMV biogenesis have been studied. This review discusses the different models that have been proposed for OMV biogenesis, along with details of the biological functions of OMVs and the likely scope of future research.
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Affiliation(s)
- Heramb M. Kulkarni
- CSIR – Centre for Cellular and Molecular Biology, Tarnaka, Hyderabad-500007, India
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32
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Production of outer membrane vesicles by the plague pathogen Yersinia pestis. PLoS One 2014; 9:e107002. [PMID: 25198697 PMCID: PMC4157834 DOI: 10.1371/journal.pone.0107002] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 08/04/2014] [Indexed: 12/24/2022] Open
Abstract
Many Gram-negative bacteria produce outer membrane vesicles (OMVs) during cell growth and division, and some bacterial pathogens deliver virulence factors to the host via the release of OMVs during infection. Here we show that Yersinia pestis, the causative agent of the disease plague, produces and releases native OMVs under physiological conditions. These OMVs, approximately 100 nm in diameter, contain multiple virulence-associated outer membrane proteins including the adhesin Ail, the F1 outer fimbrial antigen, and the protease Pla. We found that OMVs released by Y. pestis contain catalytically active Pla that is competent for plasminogen activation and α2-antiplasmin degradation. The abundance of OMV-associated proteins released by Y. pestis is significantly elevated at 37°C compared to 26°C and is increased in response to membrane stress and mutations in RseA, Hfq, and the major Braun lipoprotein (Lpp). In addition, we show that Y. pestis OMVs are able to bind to components of the extracellular matrix such as fibronectin and laminin. These data suggest that Y. pestis may produce OMVs during mammalian infection and we propose that dispersal of Pla via OMV release may influence the outcome of infection through interactions with Pla substrates such as plasminogen and Fas ligand.
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33
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Xylella fastidiosa outer membrane vesicles modulate plant colonization by blocking attachment to surfaces. Proc Natl Acad Sci U S A 2014; 111:E3910-8. [PMID: 25197068 DOI: 10.1073/pnas.1414944111] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Outer membrane vesicles (OMVs) of Gram-negative bacteria have been studied intensively in recent years, primarily in their role in delivering virulence factors and antigens during pathogenesis. However, the near ubiquity of their production suggests that they may play other roles, such as responding to envelope stress or trafficking various cargoes to prevent dilution or degradation by other bacterial species. Here we show that OMVs produced by Xylella fastidiosa, a xylem-colonizing plant pathogenic bacterium, block its interaction with various surfaces such as the walls of xylem vessels in host plants. The release of OMVs was suppressed by the diffusible signal factor-dependent quorum-sensing system, and a X. fastidiosa ΔrpfF mutant in which quorum signaling was disrupted was both much more virulent to plants and less adhesive to glass and plant surfaces than the WT strain. The higher virulence of the ΔrpfF mutant was associated with fivefold higher numbers of OMVs recovered from xylem sap of infected plants. The frequency of attachment of X. fastidiosa to xylem vessels was 20-fold lower in the presence of OMVs than in their absence. OMV production thus is a strategy used by X. fastidiosa cells to adjust attachment to surfaces in its transition from adhesive cells capable of insect transmission to an "exploratory" lifestyle for systemic spread within the plant host which would be hindered by attachment. OMV production may contribute to the movement of other bacteria in porous environments by similarly reducing their contact with environmental constituents.
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34
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Abstract
Neisseria meningitidis (meningococcus) is a major causative organism of meningitis and sepsis and Neisseria gonorrhoeae (gonococcus) is the causative organism of the sexually transmitted disease gonorrhea. Infections caused by meningococci are vaccine-preventable, whereas gonococcal vaccine research and development has languished for decades and the correlates of protection are still largely unknown. In the past two decades, complementary 'omic' platforms have been developed to interrogate Neisseria genomes and gene products. Proteomic techniques applied to whole Neisseria bacteria, outer membranes and outer membrane vesicle vaccines have generated protein maps and also allowed the examination of environmental stresses on protein expression. In particular, immuno-proteomics has identified proteins whose expression is correlated with the development of human natural immunity to meningococcal infection and colonization and following vaccination. Neisseria proteomic techniques have produced a catalog of potential vaccine antigens and investigating the functional and biological properties of these proteins could finally provide 'universal' Neisseria vaccines.
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Affiliation(s)
- Myron Christodoulides
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton, Faculty of Medicine, Southampton General Hospital, Southampton, SO16 6YD, UK
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35
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Zielke RA, Wierzbicki IH, Weber JV, Gafken PR, Sikora AE. Quantitative proteomics of the Neisseria gonorrhoeae cell envelope and membrane vesicles for the discovery of potential therapeutic targets. Mol Cell Proteomics 2014; 13:1299-317. [PMID: 24607996 PMCID: PMC4014286 DOI: 10.1074/mcp.m113.029538] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 02/28/2014] [Indexed: 01/29/2023] Open
Abstract
Neisseria gonorrhoeae (GC) is a human-specific pathogen, and the agent of a sexually transmitted disease, gonorrhea. There is a critical need for new approaches to study and treat GC infections because of the growing threat of multidrug-resistant isolates and the lack of a vaccine. Despite the implied role of the GC cell envelope and membrane vesicles in colonization and infection of human tissues and cell lines, comprehensive studies have not been undertaken to elucidate their constituents. Accordingly, in pursuit of novel molecular therapeutic targets, we have applied isobaric tagging for absolute quantification coupled with liquid chromatography and mass spectrometry for proteome quantitative analyses. Mining the proteome of cell envelopes and native membrane vesicles revealed 533 and 168 common proteins, respectively, in analyzed GC strains FA1090, F62, MS11, and 1291. A total of 22 differentially abundant proteins were discovered including previously unknown proteins. Among those proteins that displayed similar abundance in four GC strains, 34 were found in both cell envelopes and membrane vesicles fractions. Focusing on one of them, a homolog of an outer membrane protein LptD, we demonstrated that its depletion caused loss of GC viability. In addition, we selected for initial characterization six predicted outer membrane proteins with unknown function, which were identified as ubiquitous in the cell envelopes derived from examined GC isolates. These studies entitled a construction of deletion mutants and analyses of their resistance to different chemical probes. Loss of NGO1985, in particular, resulted in dramatically decreased GC viability upon treatment with detergents, polymyxin B, and chloramphenicol, suggesting that this protein functions in the maintenance of the cell envelope permeability barrier. Together, these findings underscore the concept that the cell envelope and membrane vesicles contain crucial, yet under-explored determinants of GC physiology, which may represent promising targets for designing new therapeutic interventions.
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Affiliation(s)
- Ryszard A. Zielke
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon 97331
| | - Igor H. Wierzbicki
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon 97331
| | - Jacob V. Weber
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon 97331
| | - Philip R. Gafken
- §Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024
| | - Aleksandra E. Sikora
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon 97331
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36
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Veith PD, Chen YY, Gorasia DG, Chen D, Glew MD, O’Brien-Simpson NM, Cecil JD, Holden JA, Reynolds EC. Porphyromonas gingivalis Outer Membrane Vesicles Exclusively Contain Outer Membrane and Periplasmic Proteins and Carry a Cargo Enriched with Virulence Factors. J Proteome Res 2014; 13:2420-32. [DOI: 10.1021/pr401227e] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Paul D. Veith
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Yu-Yen Chen
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Dhana G. Gorasia
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Dina Chen
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Michelle D. Glew
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Neil M. O’Brien-Simpson
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Jessica D. Cecil
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - James A. Holden
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
| | - Eric C. Reynolds
- Oral Health
CRC, Melbourne
Dental School, Bio21 Institute, The University of Melbourne, 720 Swanston
Street, Victoria, 3010, Australia
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37
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Williams JN, Weynants V, Poolman JT, Heckels JE, Christodoulides M. Immuno-proteomic analysis of human immune responses to experimental Neisseria meningitidis outer membrane vesicle vaccines identifies potential cross-reactive antigens. Vaccine 2014; 32:1280-6. [DOI: 10.1016/j.vaccine.2013.12.070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 11/25/2013] [Accepted: 12/19/2013] [Indexed: 11/26/2022]
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38
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Sanders H, Feavers IM. Adjuvant properties of meningococcal outer membrane vesicles and the use of adjuvants inNeisseria meningitidisprotein vaccines. Expert Rev Vaccines 2014; 10:323-34. [DOI: 10.1586/erv.11.10] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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39
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Bernardini G, Braconi D, Martelli P, Santucci A. Postgenomics ofNeisseria meningitidisfor vaccines development. Expert Rev Proteomics 2014; 4:667-77. [DOI: 10.1586/14789450.4.5.667] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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40
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Hung MC, Heckels JE, Christodoulides M. Potential of the adhesin complex protein ofNeisseria meningitidisfor next-generation meningococcal vaccines. Expert Rev Vaccines 2014; 12:981-4. [DOI: 10.1586/14760584.2013.828881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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41
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Campsall PA, Laupland KB, Niven DJ. Severe meningococcal infection: a review of epidemiology, diagnosis, and management. Crit Care Clin 2013; 29:393-409. [PMID: 23830646 DOI: 10.1016/j.ccc.2013.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Neisseria meningitidis, also known as meningococcus, is a relatively uncommon cause of invasive infection, but when it occurs it is frequently severe and potentially life threatening. Meningococcus should be considered and investigated promptly as a potentially etiologic pathogen in any patient with meningitis, or sepsis accompanied by a petechial rash. Suspected patients should receive early appropriate antimicrobial therapy concomitantly with confirmatory invasive diagnostic tests. Vaccines have reduced the incidence of infection with certain non-B meningococcal serogroups, and new serotype B vaccines are on the horizon. This article reviews the epidemiology, diagnosis, and management of severe meningococcal infections.
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Affiliation(s)
- Paul A Campsall
- Department of Critical Care Medicine, University of Calgary and Alberta Health Services, 3500 26th Avenue Northeast, Calgary, Alberta T1Y 6J4, Canada
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42
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Comparative proteome analysis of spontaneous outer membrane vesicles and purified outer membranes of Neisseria meningitidis. J Bacteriol 2013; 195:4425-35. [PMID: 23893116 DOI: 10.1128/jb.00625-13] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Outer membrane vesicles (OMVs) of Gram-negative bacteria receive increasing attention because of various biological functions and their use as vaccines. However, the mechanisms of OMV release and selective sorting of proteins into OMVs remain unclear. Comprehensive quantitative proteome comparisons between spontaneous OMVs (SOMVs) and the outer membrane (OM) have not been conducted so far. Here, we established a protocol for metabolic labeling of neisserial proteins with (15)N. SOMV and OM proteins labeled with (15)N were used as an internal standard for proteomic comparison of the SOMVs and OMs of two different strains. This labeling approach, coupled with high-sensitivity mass spectrometry, allowed us to comprehensively unravel the proteome of the SOMVs and OMs. We quantified the relative distribution of 155 proteins between SOMVs and the OM. Complement regulatory proteins, autotransporters, proteins involved in iron and zinc acquisition, and a two-partner secretion system were enriched in SOMVs. The highly abundant porins PorA and PorB and proteins connecting the OM with peptidoglycan or the inner membrane, such as RmpM, MtrE, and PilQ, were depleted in SOMVs. Furthermore, the three lytic transglycosylases MltA, MltB, and Slt were less abundant in SOMVs. In conclusion, SOMVs are likely to be released from surface areas with a low local abundance of membrane-anchoring proteins and lytic transglycosylases. The enrichment of complement regulatory proteins, autotransporters, and trace metal binding and transport proteins needs to be explored in the context of the pathogenesis of meningococcal disease.
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43
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Lappann M, Danhof S, Guenther F, Olivares-Florez S, Mordhorst IL, Vogel U. In vitro resistance mechanisms of Neisseria meningitidis against neutrophil extracellular traps. Mol Microbiol 2013; 89:433-49. [PMID: 23750848 DOI: 10.1111/mmi.12288] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2013] [Indexed: 02/02/2023]
Abstract
Neisseria meningitidis (Nm) is a leading cause of septicemia in childhood. Nm septicemia is unique with respect to very quick disease progression, high in vivo bacterial replication rate and its considerable mortality. Nm circumvents major mechanisms of innate immunity such as complement system and phagocytosis. Neutrophil extracellular traps (NETs) are formed from neutrophils during systemic infection and are suggested to contain invading microorganisms. Here, we investigated the interaction of Nm with NETs. Both, meningococci and spontaneously released outer membrane vesicles (SOMVs) were potent NET inducers. NETs were unable to kill NET bound meningococci, but slowed down their proliferation rate. Using Nm as model organism we identified three novel mechanisms how bacteria can evade NET-mediated killing: (i) modification of lipid A of meningococcal LPS with phosphoethanolamine protected Nm from NET-bound cathepsin G; (ii) expression of the high-affinity zinc uptake receptor ZnuD allowed Nm to escape NET-mediated nutritional immunity; (iii) binding of SOMVs to NETs saved Nm from NET binding and the consequent bacteriostatic effect. Escape from NETs may contribute to the most rapid progression of meningococcal disease. The induction of NET formation by Nm in vivo might aggravate thrombosis in vessels ultimately directing to disseminated intravascular coagulation (DIC).
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Affiliation(s)
- Martin Lappann
- Institute for Hygiene and Microbiology, University of Wuerzburg, Wuerzburg, Germany.
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44
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Sanders H, Kaaijk P, van den Dobbelsteen GP. Preclinical evaluation of MenB vaccines: prerequisites for clinical development. Expert Rev Vaccines 2013; 12:31-42. [PMID: 23256737 DOI: 10.1586/erv.12.137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Despite the widespread use of polysaccharide and conjugate vaccines against disease caused by several serogroups of Neisseria meningitidis, vaccines targeting meningococci expressing the serogroup B capsule (MenB) have focused on subcapsular antigens, due to crossreactivity of the polysaccharide with human glycoproteins. Protein vaccines composed of outer membrane vesicles have been used successfully to control epidemics of MenB disease in several countries; however, these are specific for epidemic strains. Currently, a single serogroup B vaccine, aiming to provide comprehensive coverage, has been approved for use, and several others are undergoing clinical trials. Data on potential new vaccine candidates, from discovery to initial preclinical evaluation, are regularly published. In this review, the data required to progress from preclinical to clinical development of MenB vaccines are outlined, with reference to relevant regulatory guidelines. The issues caused by a lack of reliable animal models, particularly with respect to determination of protective efficacy, are also discussed.
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Affiliation(s)
- Holly Sanders
- Bacterial Vaccines, Crucell Holland, Leiden, The Netherlands
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45
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Barker JH, Kaufman JW, Zhang DS, Weiss JP. Metabolic labeling to characterize the overall composition of Francisella lipid A and LPS grown in broth and in human phagocytes. Innate Immun 2013; 20:88-103. [PMID: 23729477 DOI: 10.1177/1753425913485308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A hallmark of Francisella tularensis, a highly virulent Gram-negative bacterium, is an unusual LPS that possesses both structural heterogeneity and characteristics that may contribute to innate immune evasion. However, none of the methods yet employed has been sufficient to determine the overall LPS composition of Francisella. We now demonstrate that metabolic labeling of francisellae with [(14)C]acetate, combined with fractionation of [(14)C]acetate-labeled lipids by ethanol precipitation rather than hot phenol-water extraction, permits a more sensitive and quantitative appraisal of overall compositional heterogeneity in lipid A and LPS. The majority of lipid A of different francisellae strains grown in diverse bacteriologic media and within human phagocytes accumulated as very hydrophobic species, including free lipid A, with <10% of the lipid A molecules substituted with O-Ag polysaccharides. The spectrum of lipid A and LPS species varied in a medium- and strain-dependent fashion, and growth in THP-1 cells yielded lipid A species that were not present in the same bacteria grown in brain heart infusion broth. In summary, metabolic labeling with [(14)C]acetate greatly facilitates assessment of the effect of genotypic and/or environmental variables on the synthesis and accumulation of lipid A and LPS by Francisella, including during growth within the cytosol of infected host cells.
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Affiliation(s)
- Jason H Barker
- 1Inflammation Program and Department of Medicine, University of Iowa and Veterans Affairs Medical Center, IA, USA
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46
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The adhesin complex protein (ACP) of Neisseria meningitidis is a new adhesin with vaccine potential. mBio 2013; 4:mBio.00041-13. [PMID: 23443003 PMCID: PMC3585444 DOI: 10.1128/mbio.00041-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The acp gene encoding the 13-kDa adhesin complex protein (ACP) from Neisseria meningitidis serogroup B strain MC58 was cloned and expressed in Escherichia coli, and the purified recombinant ACP (rACP) was used for immunization studies. Analysis of the ACP amino acid sequences from 13 meningococcal strains, isolated from patients and colonized individuals, and 178 strains in the Bacterial Isolate Genome Sequence (BIGS) database showed the presence of only three distinct sequence types (I, II, and III) with high similarity (>98%). Immunization of mice with type I rACP in detergent micelles and liposomes and in saline solution alone induced high levels of serum bactericidal activity (SBA; titers of 1/512) against the homologous strain MC58 and killed strains of heterologous sequence types II and III with similar SBA titers (1/128 to 1/512). Levels of expression of type I, II, or III ACP by different meningococcal strains were similar. ACP functioned as an adhesin, as demonstrated by reduced adherence of acp knockout (MC58 ΔACP) meningococci to human cells in vitro and the direct surface binding of rACP and by the ability of anti-rACP sera to inhibit adherence of wild-type bacteria. ACP also mediated the invasion of noncapsular meningococci into human epithelial cells, but it was not a particularly impressive invasin, as the internalized bacterial numbers were low. In summary, the newly identified ACP protein is an adhesin that induces cross-strain bactericidal activity and is therefore an attractive target antigen for incorporation into the next generation of serogroup B meningococcal vaccines. Infections caused by Neisseria meningitidis serogroup B are still significant causes of mortality and morbidity worldwide, and broadly protective vaccines of defined antigen composition are not yet licensed. Here, we describe the properties of the adhesin complex protein (ACP), which we demonstrate is a newly recognized molecule that is highly conserved and expressed to similar levels in meningococci and facilitates meningococcal interactions with human cells. We also report that a recombinant ACP protein vaccine induces murine antibodies that significantly kill meningococci expressing different ACP. Taken together, these properties demonstrate that ACP merits serious consideration as a component of a broadly protective vaccine against serogroup B meningococci.
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47
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van de Waterbeemd B, Mommen GPM, Pennings JLA, Eppink MH, Wijffels RH, van der Pol LA, de Jong APJM. Quantitative Proteomics Reveals Distinct Differences in the Protein Content of Outer Membrane Vesicle Vaccines. J Proteome Res 2013; 12:1898-908. [DOI: 10.1021/pr301208g] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Geert P. M. Mommen
- Institute for Translational Vaccinology (Intravacc), Bilthoven, The Netherlands
- Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, The Netherlands
- Netherlands Proteomics Centre, The Netherlands
| | - Jeroen L. A. Pennings
- National Institute for Public
Health and the Environment, Centre for Health Protection Research, Bilthoven, The Netherlands
| | | | | | - Leo A. van der Pol
- Institute for Translational Vaccinology (Intravacc), Bilthoven, The Netherlands
| | - Ad P. J. M. de Jong
- Institute for Translational Vaccinology (Intravacc), Bilthoven, The Netherlands
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van de Waterbeemd B, Zomer G, van den Ijssel J, van Keulen L, Eppink MH, van der Ley P, van der Pol LA. Cysteine depletion causes oxidative stress and triggers outer membrane vesicle release by Neisseria meningitidis; implications for vaccine development. PLoS One 2013; 8:e54314. [PMID: 23372704 PMCID: PMC3553081 DOI: 10.1371/journal.pone.0054314] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/11/2012] [Indexed: 12/13/2022] Open
Abstract
Outer membrane vesicles (OMV) contain immunogenic proteins and contribute to in vivo survival and virulence of bacterial pathogens. The first OMV vaccines successfully stopped Neisseria meningitidis serogroup B outbreaks but required detergent-extraction for endotoxin removal. Current vaccines use attenuated endotoxin, to preserve immunological properties and allow a detergent-free process. The preferred process is based on spontaneously released OMV (sOMV), which are most similar to in vivo vesicles and easier to purify. The release mechanism however is poorly understood resulting in low yield. This study with N. meningitidis demonstrates that an external stimulus, cysteine depletion, can trigger growth arrest and sOMV release in sufficient quantities for vaccine production (±1500 human doses per liter cultivation). Transcriptome analysis suggests that cysteine depletion impairs iron-sulfur protein assembly and causes oxidative stress. Involvement of oxidative stress is confirmed by showing that addition of reactive oxygen species during cysteine-rich growth also triggers vesiculation. The sOMV in this study are similar to vesicles from natural infection, therefore cysteine-dependent vesiculation is likely to be relevant for the in vivo pathogenesis of N. meningitidis.
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Affiliation(s)
- Bas van de Waterbeemd
- Vaccinology, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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Production of outer membrane vesicles and outer membrane tubes by Francisella novicida. J Bacteriol 2012; 195:1120-32. [PMID: 23264574 DOI: 10.1128/jb.02007-12] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella spp. are highly infectious and virulent bacteria that cause the zoonotic disease tularemia. Knowledge is lacking for the virulence factors expressed by Francisella and how these factors are secreted and delivered to host cells. Gram-negative bacteria constitutively release outer membrane vesicles (OMV), which may function in the delivery of virulence factors to host cells. We identified growth conditions under which Francisella novicida produces abundant OMV. Purification of the vesicles revealed the presence of tube-shaped vesicles in addition to typical spherical OMV, and examination of whole bacteria revealed the presence of tubes extending out from the bacterial surface. Recently, both prokaryotic and eukaryotic cells have been shown to produce membrane-enclosed projections, termed nanotubes, which appear to function in cell-cell communication and the exchange of molecules. In contrast to these previously characterized structures, the F. novicida tubes are produced in liquid as well as on solid medium and are derived from the OM rather than the cytoplasmic membrane. The production of the OMV and tubes (OMV/T) by F. novicida was coordinately regulated and responsive to both growth medium and growth phase. Proteomic analysis of purified OMV/T identified known Francisella virulence factors among the constituent proteins, suggesting roles for the vesicles in pathogenesis. In support of this, production of OM tubes by F. novicida was stimulated during infection of macrophages and addition of purified OMV/T to macrophages elicited increased release of proinflammatory cytokines. Finally, vaccination with purified OMV/T protected mice from subsequent challenge with highly lethal doses of F. novicida.
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Intranasal immunization with nontypeable Haemophilus influenzae outer membrane vesicles induces cross-protective immunity in mice. PLoS One 2012; 7:e42664. [PMID: 22880074 PMCID: PMC3411803 DOI: 10.1371/journal.pone.0042664] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 07/10/2012] [Indexed: 01/29/2023] Open
Abstract
Haemophilus influenzae is a Gram-negative human-restricted bacterium that can act as a commensal and a pathogen of the respiratory tract. Especially nontypeable H. influenzae (NTHi) is a major threat to public health and is responsible for several infectious diseases in humans, such as pneumonia, sinusitis, and otitis media. Additionally, NTHi strains are highly associated with exacerbations in patients suffering from chronic obstructive pulmonary disease. Currently, there is no licensed vaccine against NTHi commercially available. Thus, this study investigated the utilization of outer membrane vesicles (OMVs) as a potential vaccine candidate against NTHi infections. We analyzed the immunogenic and protective properties of OMVs derived from various NTHi strains by means of nasopharyngeal immunization and colonization studies with BALB/c mice. The results presented herein demonstrate that an intranasal immunization with NTHi OMVs results in a robust and complex humoral and mucosal immune response. Immunoprecipitation revealed the most important immunogenic proteins, such as the heme utilization protein, protective surface antigen D15, heme binding protein A, and the outer membrane proteins P1, P2, P5 and P6. The induced immune response conferred not only protection against colonization with a homologous NTHi strain, which served as an OMV donor for the immunization mixtures, but also against a heterologous NTHi strain, whose OMVs were not part of the immunization mixtures. These findings indicate that OMVs derived from NTHi strains have a high potential to act as a vaccine against NTHi infections.
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