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Tkalec KI, Hayes AJ, Lim KS, Lewis JM, Davies MR, Scott NE. Glycan-Tailored Glycoproteomic Analysis Reveals Serine is the Sole Residue Subjected to O-Linked Glycosylation in Acinetobacter baumannii. J Proteome Res 2024; 23:2474-2494. [PMID: 38850255 DOI: 10.1021/acs.jproteome.4c00148] [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: 06/10/2024]
Abstract
Protein glycosylation is a ubiquitous process observed across all domains of life. Within the human pathogen Acinetobacter baumannii, O-linked glycosylation is required for virulence; however, the targets and conservation of glycosylation events remain poorly defined. In this work, we expand our understanding of the breadth and site specificity of glycosylation within A. baumannii by demonstrating the value of strain specific glycan electron-transfer/higher-energy collision dissociation (EThcD) triggering for bacterial glycoproteomics. By coupling tailored EThcD-triggering regimes to complementary glycopeptide enrichment approaches, we assessed the observable glycoproteome of three A. baumannii strains (ATCC19606, BAL062, and D1279779). Combining glycopeptide enrichment techniques including ion mobility (FAIMS), metal oxide affinity chromatography (titanium dioxide), and hydrophilic interaction liquid chromatography (ZIC-HILIC), as well as the use of multiple proteases (trypsin, GluC, pepsin, and thermolysis), we expand the known A. baumannii glycoproteome to 33 unique glycoproteins containing 42 glycosylation sites. We demonstrate that serine is the sole residue subjected to glycosylation with the substitution of serine for threonine abolishing glycosylation in model glycoproteins. An A. baumannii pan-genome built from 576 reference genomes identified that serine glycosylation sites are highly conserved. Combined this work expands our knowledge of the conservation and site specificity of A. baumannii O-linked glycosylation.
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Affiliation(s)
- Kristian I Tkalec
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Andrew J Hayes
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Kataleen S Lim
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Jessica M Lewis
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Mark R Davies
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
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Sabotič J, Janež N, Volk M, Klančnik A. Molecular structures mediating adhesion of Campylobacter jejuni to abiotic and biotic surfaces. Vet Microbiol 2023; 287:109918. [PMID: 38029692 DOI: 10.1016/j.vetmic.2023.109918] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 11/13/2023] [Accepted: 11/19/2023] [Indexed: 12/01/2023]
Abstract
Microaerophilic, Gram-negative Campylobacter jejuni is the causative agent of campylobacteriosis, the most common bacterial gastrointestinal infection worldwide. Adhesion is the crucial first step in both infection or interaction with the host and biofilm formation, and is a critical factor for bacterial persistence. Here we describe the proteins and other surface structures that promote adhesion to various surfaces, including abiotic surfaces, microorganisms, and animal and human hosts. In addition, we provide insight into the distribution of adhesion proteins among strains from different ecological niches and highlight unexplored proteins involved in C. jejuni adhesion. Protein-protein, protein-glycan, and glycan-glycan interactions are involved in C. jejuni adhesion, with different factors contributing to adhesion to varying degrees under different circumstances. As adhesion is essential for survival and persistence, it represents an interesting target for C. jejuni control. Knowledge of the adhesion process is incomplete, as different molecular and functional aspects have been studied for different structures involved in adhesion. Therefore, it is important to strive for an integration of different approaches to obtain a clearer picture of the adhesion process on different surfaces and to consider the involvement of proteins, glycoconjugates, and polysaccharides and their cooperation.
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Affiliation(s)
- Jerica Sabotič
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Nika Janež
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Manca Volk
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Slovenia
| | - Anja Klančnik
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Slovenia.
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Lopes GV, Ramires T, Kleinubing NR, Scheik LK, Fiorentini ÂM, Padilha da Silva W. Virulence factors of foodborne pathogen Campylobacterjejuni. Microb Pathog 2021; 161:105265. [PMID: 34699927 DOI: 10.1016/j.micpath.2021.105265] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/27/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022]
Abstract
Campylobacter jejuni is a highly frequent cause of gastrointestinal foodborne disease in humans throughout the world. Disease outcomes vary from mild to severe diarrhea, and in rare cases the Guillain-Barré syndrome or reactive arthritis can develop as a post-infection complication. Transmission to humans usually occurs via the consumption of a range of foods, especially those associated with the consumption of raw or undercooked poultry meat, unpasteurized milk, and water-based environmental sources. When associated to food or water ingestion, the C. jejuni enters the human host intestine via the oral route and colonizes the distal ileum and colon. When it adheres and colonizes the intestinal cell surfaces, the C. jejuni is expected to express several putative virulence factors, which cause damage to the intestine either directly, by cell invasion and/or production of toxin(s), or indirectly, by triggering inflammatory responses. This review article highlights various C. jejuni characteristics - such as motility and chemotaxis - that contribute to the biological fitness of the pathogen, as well as factors involved in human host cell adhesion and invasion, and their potential role in the development of the disease. We have analyzed and critically discussed nearly 180 scientific articles covering the latest improvements in the field.
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Affiliation(s)
- Graciela Volz Lopes
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Tassiana Ramires
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Natalie Rauber Kleinubing
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Letícia Klein Scheik
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Ângela Maria Fiorentini
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Wladimir Padilha da Silva
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil.
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Cain JA, Dale AL, Sumer-Bayraktar Z, Solis N, Cordwell SJ. Identifying the targets and functions of N-linked protein glycosylation in Campylobacter jejuni. Mol Omics 2021; 16:287-304. [PMID: 32347268 DOI: 10.1039/d0mo00032a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Campylobacter jejuni is a major cause of bacterial gastroenteritis in humans that is primarily associated with the consumption of inadequately prepared poultry products, since the organism is generally thought to be asymptomatic in avian species. Unlike many other microorganisms, C. jejuni is capable of performing extensive post-translational modification (PTM) of proteins by N- and O-linked glycosylation, both of which are required for optimal chicken colonization and human virulence. The biosynthesis and attachment of N-glycans to C. jejuni proteins is encoded by the pgl (protein glycosylation) locus, with the PglB oligosaccharyltransferase (OST) enabling en bloc transfer of a heptasaccharide N-glycan from a lipid carrier in the inner membrane to proteins exposed within the periplasm. Seventy-eight C. jejuni glycoproteins (represented by 134 sites of experimentally verified N-glycosylation) have now been identified, and include inner and outer membrane proteins, periplasmic proteins and lipoproteins, which are generally of poorly defined or unknown function. Despite our extensive knowledge of the targets of this apparently widespread process, we still do not fully understand the role N-glycosylation plays biologically, although several phenotypes, including wild-type stress resistance, biofilm formation, motility and chemotaxis have been related to a functional pgl system. Recent work has described enzymatic processes (nitrate reductase NapAB) and antibiotic efflux (CmeABC) as major targets requiring N-glycan attachment for optimal function, and experimental evidence also points to roles in cell binding via glycan-glycan interactions, protein complex formation and protein stability by conferring protection against host and bacterial proteolytic activity. Here we examine the biochemistry of the N-linked glycosylation system, define its currently known protein targets and discuss evidence for the structural and functional roles of this PTM in individual proteins and globally in C. jejuni pathogenesis.
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Affiliation(s)
- Joel A Cain
- School of Life and Environmental Sciences, The University of Sydney, 2006, Australia and Charles Perkins Centre, The University of Sydney, Level 4 East, The Hub Building (D17), 2006, Australia.
| | - Ashleigh L Dale
- School of Life and Environmental Sciences, The University of Sydney, 2006, Australia and Charles Perkins Centre, The University of Sydney, Level 4 East, The Hub Building (D17), 2006, Australia.
| | - Zeynep Sumer-Bayraktar
- School of Life and Environmental Sciences, The University of Sydney, 2006, Australia and Charles Perkins Centre, The University of Sydney, Level 4 East, The Hub Building (D17), 2006, Australia.
| | - Nestor Solis
- School of Life and Environmental Sciences, The University of Sydney, 2006, Australia
| | - Stuart J Cordwell
- School of Life and Environmental Sciences, The University of Sydney, 2006, Australia and Charles Perkins Centre, The University of Sydney, Level 4 East, The Hub Building (D17), 2006, Australia. and Discipline of Pathology, School of Medical Sciences, The University of Sydney, 2006, Australia and Sydney Mass Spectrometry, The University of Sydney, 2006, Australia
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Characterization of Posttranslationally Modified Multidrug Efflux Pumps Reveals an Unexpected Link between Glycosylation and Antimicrobial Resistance. mBio 2020; 11:mBio.02604-20. [PMID: 33203757 PMCID: PMC7683400 DOI: 10.1128/mbio.02604-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The substantial rise in multidrug-resistant bacterial infections is a current global imperative. Cumulative efforts to characterize antimicrobial resistance in bacteria has demonstrated the spread of six families of multidrug efflux pumps, of which resistance-nodulation-cell division (RND) is the major mechanism of multidrug resistance in Gram-negative bacteria. RND is composed of a tripartite protein assembly and confers resistance to a range of unrelated compounds. In the major enteric pathogen Campylobacter jejuni, the three protein components of RND are posttranslationally modified with N-linked glycans. The direct role of N-linked glycans in C. jejuni and other bacteria has long been elusive. Here, we present the first detailed account of the role of N-linked glycans and the link between N-glycosylation and antimicrobial resistance in C. jejuni We demonstrate the multifunctional role of N-linked glycans in enhancing protein thermostability, stabilizing protein complexes and the promotion of protein-protein interaction, thus mediating antimicrobial resistance via enhancing multidrug efflux pump activity. This affirms that glycosylation is critical for multidrug efflux pump assembly. We present a generalized strategy that could be used to investigate general glycosylation system in Campylobacter genus and a potential target to develop antimicrobials against multidrug-resistant pathogens.IMPORTANCE Nearly all bacterial species have at least a single glycosylation system, but the direct effects of these posttranslational protein modifications are unresolved. Glycoproteome-wide analysis of several bacterial pathogens has revealed general glycan modifications of virulence factors and protein assemblies. Using Campylobacter jejuni as a model organism, we have studied the role of general N-linked glycans in the multidrug efflux pump commonly found in Gram-negative bacteria. We show, for the first time, the direct link between N-linked glycans and multidrug efflux pump activity. At the protein level, we demonstrate that N-linked glycans play a role in enhancing protein thermostability and mediating the assembly of the multidrug efflux pump to promote antimicrobial resistance, highlighting the importance of this posttranslational modification in bacterial physiology. Similar roles for glycans are expected to be found in other Gram-negative pathogens that possess general protein glycosylation systems.
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Campylobacter jejuni BumSR directs a response to butyrate via sensor phosphatase activity to impact transcription and colonization. Proc Natl Acad Sci U S A 2020; 117:11715-11726. [PMID: 32398371 DOI: 10.1073/pnas.1922719117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Campylobacter jejuni monitors intestinal metabolites produced by the host and microbiota to initiate intestinal colonization of avian and animal hosts for commensalism and infection of humans for diarrheal disease. We previously discovered that C. jejuni has the capacity to spatially discern different intestinal regions by sensing lactate and the short-chain fatty acids acetate and butyrate and then alter transcription of colonization factors appropriately for in vivo growth. In this study, we identified the C. jejuni butyrate-modulated regulon and discovered that the BumSR two-component signal transduction system (TCS) directs a response to butyrate by identifying mutants in a genetic screen defective for butyrate-modulated transcription. The BumSR TCS, which is important for infection of humans and optimal colonization of avian hosts, senses butyrate likely by indirect means to alter transcription of genes encoding important colonization determinants. Unlike many canonical TCSs, the predicted cytoplasmic sensor kinase BumS lacked in vitro autokinase activity, which would normally lead to phosphorylation of the cognate BumR response regulator. Instead, BumS has likely evolved mutations to naturally function as a phosphatase whose activity is influenced by exogenous butyrate to control the level of endogenous phosphorylation of BumR and its ability to alter transcription of target genes. To our knowledge, the BumSR TCS is the only bacterial signal transduction system identified so far that mediates responses to the microbiota-generated intestinal metabolite butyrate, an important factor for host intestinal health and homeostasis. Our findings suggest that butyrate sensing by this system is vital for C. jejuni colonization of multiple hosts.
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Konkel ME, Talukdar PK, Negretti NM, Klappenbach CM. Taking Control: Campylobacter jejuni Binding to Fibronectin Sets the Stage for Cellular Adherence and Invasion. Front Microbiol 2020; 11:564. [PMID: 32328046 PMCID: PMC7161372 DOI: 10.3389/fmicb.2020.00564] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 03/16/2020] [Indexed: 12/18/2022] Open
Abstract
Campylobacter jejuni, a foodborne pathogen, is one of the most common bacterial causes of gastroenteritis in the world. Undercooked poultry, raw (unpasteurized) dairy products, untreated water, and contaminated produce are the most common sources associated with infection. C. jejuni establishes a niche in the gut by adhering to and invading epithelial cells, which results in diarrhea with blood and mucus in the stool. The process of colonization is mediated, in part, by surface-exposed molecules (adhesins) that bind directly to host cell ligands or the extracellular matrix (ECM) surrounding cells. In this review, we introduce the known and putative adhesins of the foodborne pathogen C. jejuni. We then focus our discussion on two C. jejuni Microbial Surface Components Recognizing Adhesive Matrix Molecule(s) (MSCRAMMs), termed CadF and FlpA, which have been demonstrated to contribute to C. jejuni colonization and pathogenesis. In vitro studies have determined that these two surface-exposed proteins bind to the ECM glycoprotein fibronectin (FN). In vivo studies have shown that cadF and flpA mutants exhibit impaired colonization of chickens compared to the wild-type strain. Additional studies have revealed that CadF and FlpA stimulate epithelial cell signaling pathways necessary for cell invasion. Interestingly, CadF and FlpA have distinct FN-binding domains, suggesting that the functions of these proteins are non-redundant. In summary, the binding of FN by C. jejuni CadF and FlpA adhesins has been demonstrated to contribute to adherence, invasion, and cell signaling.
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Affiliation(s)
- Michael E. Konkel
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
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Negretti NM, Clair G, Talukdar PK, Gourley CR, Huynh S, Adkins JN, Parker CT, Corneau CM, Konkel ME. Campylobacter jejuni Demonstrates Conserved Proteomic and Transcriptomic Responses When Co-cultured With Human INT 407 and Caco-2 Epithelial Cells. Front Microbiol 2019; 10:755. [PMID: 31031730 PMCID: PMC6470190 DOI: 10.3389/fmicb.2019.00755] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 03/26/2019] [Indexed: 12/21/2022] Open
Abstract
Major foodborne bacterial pathogens, such as Campylobacter jejuni, have devised complex strategies to establish and foster intestinal infections. For more than two decades, researchers have used immortalized cell lines derived from human intestinal tissue to dissect C. jejuni-host cell interactions. Known from these studies is that C. jejuni virulence is multifactorial, requiring a coordinated response to produce virulence factors that facilitate host cell interactions. This study was initiated to identify C. jejuni proteins that contribute to adaptation to the host cell environment and cellular invasion. We demonstrated that C. jejuni responds to INT 407 and Caco-2 cells in a similar fashion at the cellular and molecular levels. Active protein synthesis was found to be required for C. jejuni to maximally invade these host cells. Proteomic and transcriptomic approaches were then used to define the protein and gene expression profiles of C. jejuni co-cultured with cells. By focusing on those genes showing increased expression by C. jejuni when co-cultured with epithelial cells, we discovered that C. jejuni quickly adapts to co-culture with epithelial cells by synthesizing gene products that enable it to acquire specific amino acids for growth, scavenge for inorganic molecules including iron, resist reactive oxygen/nitrogen species, and promote host cell interactions. Based on these findings, we selected a subset of the genes involved in chemotaxis and the regulation of flagellar assembly and generated C. jejuni deletion mutants for phenotypic analysis. Binding and internalization assays revealed significant differences in the interaction of C. jejuni chemotaxis and flagellar regulatory mutants. The identification of genes involved in C. jejuni adaptation to culture with host cells provides new insights into the infection process.
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Affiliation(s)
- Nicholas M. Negretti
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Geremy Clair
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Prabhat K. Talukdar
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Christopher R. Gourley
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Steven Huynh
- Produce Safety and Microbiology, United States Department of Agriculture-Agricultural Research Service, Albany, CA, United States
| | - Joshua N. Adkins
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Craig T. Parker
- Produce Safety and Microbiology, United States Department of Agriculture-Agricultural Research Service, Albany, CA, United States
| | - Colby M. Corneau
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Michael E. Konkel
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
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Lin Y, Reino C, Carrera J, Pérez J, van Loosdrecht MCM. Glycosylated amyloid-like proteins in the structural extracellular polymers of aerobic granular sludge enriched with ammonium-oxidizing bacteria. Microbiologyopen 2018; 7:e00616. [PMID: 29604180 PMCID: PMC6291783 DOI: 10.1002/mbo3.616] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 01/20/2018] [Accepted: 02/10/2018] [Indexed: 12/31/2022] Open
Abstract
A new type of structural extracellular polymers (EPS) was extracted from aerobic granular sludge dominated by ammonium-oxidizing bacteria. It was analyzed by Raman and FTIR spectroscopy to characterize specific amino acids and protein secondary structure, and by SDS-PAGE with different stains to identify different glycoconjugates. Its intrinsic fluorescence was captured to visualize the location of the extracted EPS in the nitrifying granules, and its hydrogel-forming property was studied by rheometry. The extracted EPS is abundant with cross ß-sheet secondary structure, contains glycosylated proteins/polypeptides, and rich in tryptophan. It forms hydrogel with high mechanical strength. The extraction and discovery of glycosylated proteins and/or amyloids further shows that conventionally used extraction and characterization techniques are not adequate for the study of structural extracellular polymers in biofilms and/or granular sludge. Confirming amyloids secondary structure in such a complex sample is challengeable due to the possibility of amyloids glycosylation and self-assembly. A new definition of extracellular polymers components which includes glycosylated proteins and a better approach to studying them is required to stimulate biofilm research.
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Affiliation(s)
- Yuemei Lin
- Department of BiotechnologyFaculty of Applied SciencesDelft University of TechnologyDelftThe Netherlands
| | - Clara Reino
- GENOCOV Research GroupDepartment of Chemical, Biological and Environmental EngineeringSchool of EngineeringUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - Julián Carrera
- GENOCOV Research GroupDepartment of Chemical, Biological and Environmental EngineeringSchool of EngineeringUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - Julio Pérez
- Department of BiotechnologyFaculty of Applied SciencesDelft University of TechnologyDelftThe Netherlands
| | - Mark C. M. van Loosdrecht
- Department of BiotechnologyFaculty of Applied SciencesDelft University of TechnologyDelftThe Netherlands
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Liu MM, Boinett CJ, Chan ACK, Parkhill J, Murphy MEP, Gaynor EC. Investigating the Campylobacter jejuni Transcriptional Response to Host Intestinal Extracts Reveals the Involvement of a Widely Conserved Iron Uptake System. mBio 2018; 9:e01347-18. [PMID: 30087169 PMCID: PMC6083913 DOI: 10.1128/mbio.01347-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 06/27/2018] [Indexed: 12/20/2022] Open
Abstract
Campylobacter jejuni is a pathogenic bacterium that causes gastroenteritis in humans yet is a widespread commensal in wild and domestic animals, particularly poultry. Using RNA sequencing, we assessed C. jejuni transcriptional responses to medium supplemented with human fecal versus chicken cecal extracts and in extract-supplemented medium versus medium alone. C. jejuni exposed to extracts had altered expression of 40 genes related to iron uptake, metabolism, chemotaxis, energy production, and osmotic stress response. In human fecal versus chicken cecal extracts, C. jejuni displayed higher expression of genes involved in respiration (fdhTU) and in known or putative iron uptake systems (cfbpA, ceuB, chuC, and CJJ81176_1649-1655 [here designated 1649-1655]). The 1649-1655 genes and downstream overlapping gene 1656 were investigated further. Uncharacterized homologues of this system were identified in 33 diverse bacterial species representing 6 different phyla, 21 of which are associated with human disease. The 1649 and 1650 (p19) genes encode an iron transporter and a periplasmic iron binding protein, respectively; however, the role of the downstream 1651-1656 genes was unknown. A Δ1651-1656 deletion strain had an iron-sensitive phenotype, consistent with a previously characterized Δp19 mutant, and showed reduced growth in acidic medium, increased sensitivity to streptomycin, and higher resistance to H2O2 stress. In iron-restricted medium, the 1651-1656 and p19 genes were required for optimal growth when using human fecal extracts as an iron source. Collectively, this implicates a function for the 1649-1656 gene cluster in C. jejuni iron scavenging and stress survival in the human intestinal environment.IMPORTANCE Direct comparative studies of C. jejuni infection of a zoonotic commensal host and a disease-susceptible host are crucial to understanding the causes of infection outcome in humans. These studies are hampered by the lack of a disease-susceptible animal model reliably displaying a similar pathology to human campylobacteriosis. In this work, we compared the phenotypic and transcriptional responses of C. jejuni to intestinal compositions of humans (disease-susceptible host) and chickens (zoonotic host) by using human fecal and chicken cecal extracts. The mammalian gut is a complex and dynamic system containing thousands of metabolites that contribute to host health and modulate pathogen activity. We identified C. jejuni genes more highly expressed during exposure to human fecal extracts in comparison to chicken cecal extracts and differentially expressed in extracts compared with medium alone, and targeted one specific iron uptake system for further molecular, genetic, and phenotypic study.
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Affiliation(s)
- Martha M Liu
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Christine J Boinett
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Anson C K Chan
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Julian Parkhill
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Michael E P Murphy
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Erin C Gaynor
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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Khattak F, Paschalis V, Green M, Houdijk JGM, Soultanas P, Mahdavi J. TYPLEX® Chelate, a novel feed additive, inhibits Campylobacter jejuni biofilm formation and cecal colonization in broiler chickens. Poult Sci 2018; 97:1391-1399. [PMID: 29462463 PMCID: PMC5914411 DOI: 10.3382/ps/pex413] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/01/2017] [Indexed: 12/03/2022] Open
Abstract
Reducing Campylobacter spp. carriage in poultry is challenging, but essential to control this major cause of human bacterial gastroenteritis worldwide. Although much is known about the mechanisms and route of Campylobacter spp. colonization in poultry, the literature is scarce on antibiotic-free solutions to combat Campylobacter spp. colonization in poultry. In vitro and in vivo studies were conducted to investigate the role of TYPLEX® Chelate (ferric tyrosine), a novel feed additive, in inhibiting Campylobacter jejuni (C. jejuni) biofilm formation and reducing C. jejuni and Escherichia coli (E. coli) colonization in broiler chickens at market age. In an in vitro study, the inhibitory effect on C. jejuni biofilm formation using a plastic bead assay was investigated. The results demonstrated that TYPLEX® Chelate significantly reduces biofilm formation. In an in vivo study, 800 broilers (one d old) were randomly allocated to 4 dietary treatments in a randomized block design, each having 10 replicate pens with 20 birds per pen. At d 21, all birds were challenged with C. jejuni via seeded litter. At d 42, cecal samples were collected and tested for volatile fatty acid (VFA) concentrations and C. jejuni and E. coli counts. The results showed that TYPLEX® Chelate reduced the carriage of C. jejuni and E. coli in poultry by 2 and 1 log10 per gram cecal sample, respectively, and increased cecal VFA concentrations. These findings support TYPLEX® Chelate as a novel non-antibiotic feed additive that may help produce poultry with a lower public health risk of Campylobacteriosis.
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Affiliation(s)
- F Khattak
- Monogastric Science Research Center, Scotland Rural College (SRUC), Ayr, KA6 5HW, Scotland, UK
| | - V Paschalis
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, NG7 2RD, UK
| | - M Green
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, NG7 2RD, UK
| | - J G M Houdijk
- Monogastric Science Research Center, Scotland Rural College (SRUC), Ayr, KA6 5HW, Scotland, UK
| | - P Soultanas
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, NG7 2RD, UK
| | - J Mahdavi
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, NG7 2RD, UK
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Microbiota-Derived Short-Chain Fatty Acids Modulate Expression of Campylobacter jejuni Determinants Required for Commensalism and Virulence. mBio 2017; 8:mBio.00407-17. [PMID: 28487428 PMCID: PMC5424204 DOI: 10.1128/mbio.00407-17] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Campylobacter jejuni promotes commensalism in the intestinal tracts of avian hosts and diarrheal disease in humans, yet components of intestinal environments recognized as spatial cues specific for different intestinal regions by the bacterium to initiate interactions in either host are mostly unknown. By analyzing a C. jejuni acetogenesis mutant defective in converting acetyl coenzyme A (Ac-CoA) to acetate and commensal colonization of young chicks, we discovered evidence for in vivo microbiota-derived short-chain fatty acids (SCFAs) and organic acids as cues recognized by C. jejuni that modulate expression of determinants required for commensalism. We identified a set of C. jejuni genes encoding catabolic enzymes and transport systems for amino acids required for in vivo growth whose expression was modulated by SCFAs. Transcription of these genes was reduced in the acetogenesis mutant but was restored upon supplementation with physiological concentrations of the SCFAs acetate and butyrate present in the lower intestinal tracts of avian and human hosts. Conversely, the organic acid lactate, which is abundant in the upper intestinal tract where C. jejuni colonizes less efficiently, reduced expression of these genes. We propose that microbiota-generated SCFAs and lactate are cues for C. jejuni to discriminate between different intestinal regions. Spatial gradients of these metabolites likely allow C. jejuni to locate preferred niches in the lower intestinal tract and induce expression of factors required for intestinal growth and commensal colonization. Our findings provide insights into the types of cues C. jejuni monitors in the avian host for commensalism and likely in humans to promote diarrheal disease. Campylobacter jejuni is a commensal of the intestinal tracts of avian species and other animals and a leading cause of diarrheal disease in humans. The types of cues sensed by C. jejuni to influence responses to promote commensalism or infection are largely lacking. By analyzing a C. jejuni acetogenesis mutant, we discovered a set of genes whose expression is modulated by lactate and short-chain fatty acids produced by the microbiota in the intestinal tract. These genes include those encoding catabolic enzymes and transport systems for amino acids that are required by C. jejuni for in vivo growth and intestinal colonization. We propose that gradients of these microbiota-generated metabolites are cues for spatial discrimination between areas of the intestines so that the bacterium can locate niches in the lower intestinal tract for optimal growth for commensalism in avian species and possibly infection of human hosts leading to diarrheal disease.
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Silverman JM, Imperiali B. Bacterial N-Glycosylation Efficiency Is Dependent on the Structural Context of Target Sequons. J Biol Chem 2016; 291:22001-22010. [PMID: 27573243 DOI: 10.1074/jbc.m116.747121] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Indexed: 01/08/2023] Open
Abstract
Site selectivity of protein N-linked glycosylation is dependent on many factors, including accessibility of the modification site, amino acid composition of the glycosylation consensus sequence, and cellular localization of target proteins. Previous studies have shown that the bacterial oligosaccharyltransferase, PglB, of Campylobacter jejuni favors acceptor proteins with consensus sequences ((D/E)X1NX2(S/T), where X1,2 ≠ proline) in flexible, solvent-exposed motifs; however, several native glycoproteins are known to harbor consensus sequences within structured regions of the acceptor protein, suggesting that unfolding or partial unfolding is required for efficient N-linked glycosylation in the native environment. To derive insight into these observations, we generated structural homology models of the N-linked glycoproteome of C. jejuni This evaluation highlights the potential diversity of secondary structural conformations of previously identified N-linked glycosylation sequons. Detailed assessment of PglB activity with a structurally characterized acceptor protein, PEB3, demonstrated that this natively folded substrate protein is not efficiently glycosylated in vitro, whereas structural destabilization increases glycosylation efficiency. Furthermore, in vivo glycosylation studies in both glyco-competent Escherichia coli and the native system, C. jejuni, revealed that efficient glycosylation of glycoproteins, AcrA and PEB3, depends on translocation to the periplasmic space via the general secretory pathway. Our studies provide quantitative evidence that many acceptor proteins are likely to be N-linked-glycosylated before complete folding and suggest that PglB activity is coupled to general secretion-mediated translocation to the periplasm. This work extends our understanding of the molecular mechanisms underlying N-linked glycosylation in bacteria.
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Affiliation(s)
- Julie Michelle Silverman
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Barbara Imperiali
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Dantu SC, Khavnekar S, Kale A. Conformational dynamics of Peb4 exhibit “mother’s arms” chain model: a molecular dynamics study. J Biomol Struct Dyn 2016; 35:2186-2196. [DOI: 10.1080/07391102.2016.1209131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Sarath Chandra Dantu
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sagar Khavnekar
- UM-DAE Centre for Excellence in Basic Science, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India
| | - Avinash Kale
- UM-DAE Centre for Excellence in Basic Science, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India
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Zhu F, Wu H. Insights into bacterial protein glycosylation in human microbiota. SCIENCE CHINA. LIFE SCIENCES 2016; 59:11-8. [PMID: 26712033 PMCID: PMC5298937 DOI: 10.1007/s11427-015-4980-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/05/2015] [Indexed: 01/14/2023]
Abstract
The study of human microbiota is an emerging research topic. The past efforts have mainly centered on studying the composition and genomic landscape of bacterial species within the targeted communities. The interaction between bacteria and hosts is the pivotal event in the initiation and progression of infectious diseases. There is a great need to identify and characterize the molecules that mediate the bacteria-host interaction. Bacterial surface exposed proteins play an important role in the bacteria- host interaction. Numerous surface proteins are glycosylated, and the glycosylation is crucial for their function in mediating the bacterial interaction with hosts. Here we present an overview of surface glycoproteins from bacteria that inhabit three major mucosal environments across human body: oral, gut and skin. We describe the important enzymes involved in the process of protein glycosylation, and discuss how the process impacts the bacteria-host interaction. Emerging molecular details underlying glycosylation of bacterial surface proteins may lead to new opportunities for designing anti-infective small molecules, and developing novel vaccines in order to treat or prevent bacterial infection.
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Affiliation(s)
- Fan Zhu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hui Wu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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Mills DC, Jervis AJ, Abouelhadid S, Yates LE, Cuccui J, Linton D, Wren BW. Functional analysis of N-linking oligosaccharyl transferase enzymes encoded by deep-sea vent proteobacteria. Glycobiology 2015; 26:398-409. [PMID: 26610891 DOI: 10.1093/glycob/cwv111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/20/2015] [Indexed: 01/04/2023] Open
Abstract
Bacterial N-linking oligosaccharyl transferases (OTase enzymes) transfer lipid-linked glycans to selected proteins in the periplasm and were first described in the intestinal pathogen Campylobacter jejuni, a member of the ε-proteobacteria-subdivision of bacteria. More recently, orthologues from other ε-proteobacterial Campylobacter and Helicobacter species and a δ-proteobacterium, Desulfovibrio desulfuricans, have been described, suggesting that these two subdivisions of bacteria may be a source of further N-linked protein glycosylation systems. Whole-genome sequencing of both ε- and δ-proteobacteria from deep-sea vent habitats, a rich source of species from these subdivisions, revealed putative ORFs encoding OTase enzymes and associated adjacent glycosyltransferases similar to the C. jejuni N-linked glycosylation locus. We expressed putative OTase ORFs from the deep-sea vent species Nitratiruptor tergarcus, Sulfurovum lithotrophicum and Deferribacter desulfuricans in Escherichia coli and showed that they were able to functionally complement the C. jejuni OTase, CjPglB. The enzymes were shown to possess relaxed glycan specificity, transferring diverse glycan structures and demonstrated different glycosylation sequon specificities. Additionally, a permissive D. desulfuricans acceptor protein was identified, and we provide evidence that the N-linked glycan synthesized by N. tergarcus and S. lithotrophicum contains an acetylated sugar at the reducing end. This work demonstrates that deep-sea vent bacteria encode functional N-glycosylation machineries and are a potential source of biotechnologically important OTase enzymes.
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Affiliation(s)
- Dominic C Mills
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Adrian J Jervis
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - Sherif Abouelhadid
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Laura E Yates
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Jon Cuccui
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Dennis Linton
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - Brendan W Wren
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
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Analysis of the activity and regulon of the two-component regulatory system composed by Cjj81176_1484 and Cjj81176_1483 of Campylobacter jejuni. J Bacteriol 2015; 197:1592-605. [PMID: 25691530 DOI: 10.1128/jb.02564-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/11/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Campylobacter jejuni is a leading cause of bacterial diarrheal disease and a frequent commensal of the intestinal tract in poultry and other animals. For optimal growth and colonization of hosts, C. jejuni employs two-component regulatory systems (TCSs) to monitor environmental conditions and promote proper expression of specific genes. We analyzed the potential of C. jejuni Cjj81176_1484 (Cjj1484) and Cjj81176_1483 (Cjj1483) to encode proteins of a cognate TCS that influences expression of genes possibly important for C. jejuni growth and colonization. Transcriptome analysis revealed that the regulons of the Cjj81176_1484 (Cjj1484) histidine kinase and the Cjj81176_1483 (Cjj1483) response regulator contain many common genes, suggesting that these proteins likely form a cognate TCS. We found that this TCS generally functions to repress expression of specific proteins with roles in metabolism, iron/heme acquisition, and respiration. Furthermore, the TCS repressed expression of Cjj81176_0438 and Cjj81176_0439, which had previously been found to encode a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract. However, the TCS and other specific genes whose expression is repressed by the TCS were not required for colonization of chicks. We observed that the Cjj1483 response regulator binds target promoters in both unphosphorylated and phosphorylated forms and influences expression of some specific genes independently of the Cjj1484 histidine kinase. This work further expands the signaling mechanisms of C. jejuni and provides additional insights regarding the complex and multifactorial regulation of many genes involved in basic metabolism, respiration, and nutrient acquisition that the bacterium requires for optimal growth in different environments. IMPORTANCE Bacterial two-component regulatory systems (TCSs) link environmental cues to expression of specific genes that enable optimal bacterial growth or colonization of hosts. We found that the Campylobacter jejuni Cjj1484 histidine kinase and Cjj1483 response regulator function as a cognate TCS to largely repress expression of target genes encoding a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract, as well as other genes encoding proteins for heme or iron acquisition, metabolism, and respiration. We also discovered different modes by which Cjj1483 may mediate repression with and without Cjj1484. This work provides insight into the signal transduction mechanisms of a leading cause of bacterial diarrheal disease and emphasizes the multifactorial and complex regulation of specific biological processes in C. jejuni.
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Bolton DJ. Campylobacter virulence and survival factors. Food Microbiol 2014; 48:99-108. [PMID: 25790997 DOI: 10.1016/j.fm.2014.11.017] [Citation(s) in RCA: 205] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/26/2014] [Accepted: 11/30/2014] [Indexed: 10/24/2022]
Abstract
Despite over 30 years of research, campylobacteriosis is the most prevalent foodborne bacterial infection in many countries including in the European Union and the United States of America. However, relatively little is known about the virulence factors in Campylobacter or how an apparently fragile organism can survive in the food chain, often with enhanced pathogenicity. This review collates information on the virulence and survival determinants including motility, chemotaxis, adhesion, invasion, multidrug resistance, bile resistance and stress response factors. It discusses their function in transition through the food processing environment and human infection. In doing so it provides a fundamental understanding of Campylobacter, critical for improved diagnosis, surveillance and control.
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Affiliation(s)
- Declan J Bolton
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
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Mahdavi J, Pirinccioglu N, Oldfield NJ, Carlsohn E, Stoof J, Aslam A, Self T, Cawthraw SA, Petrovska L, Colborne N, Sihlbom C, Borén T, Wooldridge KG, Ala'Aldeen DAA. A novel O-linked glycan modulates Campylobacter jejuni major outer membrane protein-mediated adhesion to human histo-blood group antigens and chicken colonization. Open Biol 2014; 4:130202. [PMID: 24451549 PMCID: PMC3909276 DOI: 10.1098/rsob.130202] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Campylobacter jejuni is an important cause of human foodborne gastroenteritis; strategies to prevent infection are hampered by a poor understanding of the complex interactions between host and pathogen. Previous work showed that C. jejuni could bind human histo-blood group antigens (BgAgs) in vitro and that BgAgs could inhibit the binding of C. jejuni to human intestinal mucosa ex vivo. Here, the major flagella subunit protein (FlaA) and the major outer membrane protein (MOMP) were identified as BgAg-binding adhesins in C. jejuni NCTC11168. Significantly, the MOMP was shown to be O-glycosylated at Thr268; previously only flagellin proteins were known to be O-glycosylated in C. jejuni. Substitution of MOMP Thr268 led to significantly reduced binding to BgAgs. The O-glycan moiety was characterized as Gal(β1–3)-GalNAc(β1–4)-GalNAc(β1–4)-GalNAcα1-Thr268; modelling suggested that O-glycosylation has a notable effect on the conformation of MOMP and this modulates BgAg-binding capacity. Glycosylation of MOMP at Thr268 promoted cell-to-cell binding, biofilm formation and adhesion to Caco-2 cells, and was required for the optimal colonization of chickens by C. jejuni, confirming the significance of this O-glycosylation in pathogenesis.
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Affiliation(s)
- Jafar Mahdavi
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
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Mansell TJ, Guarino C, DeLisa MP. Engineered genetic selection links in vivo protein folding and stability with asparagine-linked glycosylation. Biotechnol J 2013; 8:1445-51. [DOI: 10.1002/biot.201300026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/20/2013] [Accepted: 07/22/2013] [Indexed: 11/07/2022]
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Application of protein purification methods for the enrichment of a cytotoxin from Campylobacter jejuni. BMC Microbiol 2012; 12:303. [PMID: 23259594 PMCID: PMC3541203 DOI: 10.1186/1471-2180-12-303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/18/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Campylobater jejuni, a major foodborne diarrhoeal pathogen is reported to produce a number of cytotoxins of which only a cytolethal distending toxin (CDT) has been characterised so far. One or more additional cytotoxins other than CDT, including a Chinese hamster ovary (CHO) cell active, Vero cell inactive cytotoxin, may mediate inflammatory diarrhoea. Our objective was to develop a method to enrich and thus partially characterise this cytotoxin, as a pathway to the eventual identification and characterisation of the toxin. RESULTS A number of biochemical methods including cation- and anion-exchange chromatography were evaluated to enrich the cytotoxin from a cell lysate of a known cytotoxin-producing C. jejuni, C31. The cytotoxin in crude lysate was initially prepared by size-exclusion desalting and then subjected to high pressure liquid chromatography (HPLC) ion-exchange fractionation. One pooled fraction (pool B) was cytotoxic for CHO cells equivalent to crude toxin (tissue culture infectivity dose 50 [TCID(50)] of 1-2 μg/ml). The proteins of pool B were identified by mass spectrometry (MS) after separation by SDS-PAGE and trypsin digestion. Also, pool B was directly digested with trypsin and then subjected to liquid chromatography tandem mass spectrometry (LCMS) analysis for identification of lesser abundant proteins in the fraction. A total of 41 proteins were found in the fraction, which included enzymes involved in metabolic and transport functions. Eighteen non-cytoplasmic proteins including 2 major antigenic peptide proteins (PEB2 and PEB3) and 3 proteins of unknown function were also identified in the screen. Cytotoxicity in pool B was trypsin-sensitive indicating its protein nature. The cytotoxic activity was heat-stable to 50°C, and partially inactivated at 60-70°C. The pool B fraction also induced fluid accumulation in the adult rabbit ileal loop assay with cytotoxicity for mucosa confirming the presence of the cytotoxin. CONCLUSIONS We report the enrichment and partial purification of C. jejuni cytotoxin by HPLC ion-exchange chromatography. Further purification may be achieved using additional complementary chromatographic techniques. A short-list of six candidate cytotoxin proteins was identified using an LCMS screen of pool B. Successful isolation of the cytotoxin will initiate steps for the determination of the role of this cytotoxin in the pathogenesis of C. jejuni diarrhoea.
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Campylobacter jejuni outer membrane vesicles play an important role in bacterial interactions with human intestinal epithelial cells. Infect Immun 2012; 80:4089-98. [PMID: 22966047 DOI: 10.1128/iai.00161-12] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Campylobacter jejuni is the most prevalent cause of food-borne gastroenteritis in the developed world; however, the molecular basis of pathogenesis is unclear. Secretion of virulence factors is a key mechanism by which enteric bacterial pathogens interact with host cells to enhance survival and/or damage the host. However, C. jejuni lacks the virulence-associated secretion systems possessed by other enteric pathogens. Many bacterial pathogens utilize outer membrane vesicles (OMVs) for delivery of virulence factors into host cells. In the absence of prototypical virulence-associated secretion systems, OMVs could be an important alternative for the coordinated delivery of C. jejuni proteins into host cells. Proteomic analysis of C. jejuni 11168H OMVs identified 151 proteins, including periplasmic and outer membrane-associated proteins, but also many determinants known to be important in survival and pathogenesis, including the cytolethal distending toxin (CDT). C. jejuni OMVs contained 16 N-linked glycoproteins, indicating a delivery mechanism by which these periplasm-located yet immunogenic glycoproteins can interact with host cells. C. jejuni OMVs possess cytotoxic activity and induce a host immune response from T84 intestinal epithelial cells (IECs), which was not reduced by OMV pretreatment with proteinase K or polymyxin B prior to coincubation with IECs. Pretreatment of IECs with methyl-beta-cyclodextrin partially blocks OMV-induced host immune responses, indicating a role for lipid rafts in host cell plasma membranes during interactions with C. jejuni OMVs. OMVs isolated from a C. jejuni 11168H cdtA mutant induced interleukin-8 (IL-8) to the same extent as did wild-type OMVs, suggesting OMV induction of IL-8 is independent of CDT.
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Rubinchik S, Seddon A, Karlyshev AV. Molecular mechanisms and biological role of Campylobacter jejuni attachment to host cells. Eur J Microbiol Immunol (Bp) 2012; 2:32-40. [PMID: 24611119 DOI: 10.1556/eujmi.2.2012.1.6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 01/13/2023] Open
Abstract
Adhesion to host cells is an important step in pathogenesis of Campylobacter jejuni, which is the most prevalent bacterial cause of human gastroenteritis worldwide. In contrast to other bacteria such as E. coli and Salmonella, adherence of C. jejuni is not mediated by fimbria or pili. A number of C. jejuni adhesion-related factors have been described. However, the results obtained by different researchers in different laboratories are often contradictory and inconclusive, with only some of the factors described being confirmed as true adhesins. In this review, we present the current state of studies on the mechanisms of attachment of C. jejuni to host cells.
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Affiliation(s)
- S Rubinchik
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
| | - A Seddon
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
| | - A V Karlyshev
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
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O Cróinín T, Backert S. Host epithelial cell invasion by Campylobacter jejuni: trigger or zipper mechanism? Front Cell Infect Microbiol 2012; 2:25. [PMID: 22919617 PMCID: PMC3417527 DOI: 10.3389/fcimb.2012.00025] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 02/17/2012] [Indexed: 11/18/2022] Open
Abstract
Campylobacter jejuni, a spiral-shaped Gram-negative pathogen, is a highly frequent cause of gastrointestinal foodborne illness in humans worldwide. Clinical outcome of C. jejuni infections ranges from mild to severe diarrheal disease, and some other complications including reactive arthritis and Guillain–Barré syndrome. This review article highlights various C. jejuni pathogenicity factors, host cell determinants, and proposed signaling mechanisms involved in human host cell invasion and their potential role in the development of C. jejuni-mediated disease. A model is presented which outlines the various important interactions of C. jejuni with the intestinal epithelium, and we discuss the pro’s and con’s for the “zipper” over the “trigger” mechanism of invasion. Future work should clarify the contradictory role of some previously identified factors, and should identify and characterize novel virulence determinants, which are crucial to provide fresh insights into the diversity of strategies employed by this pathogen to cause disease.
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Affiliation(s)
- Tadhg O Cróinín
- UCD School of Biomolecular and Biomedical Sciences, University College Dublin Dublin, Ireland
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Hepworth PJ, Ashelford KE, Hinds J, Gould KA, Witney AA, Williams NJ, Leatherbarrow H, French NP, Birtles RJ, Mendonca C, Dorrell N, Wren BW, Wigley P, Hall N, Winstanley C. Genomic variations define divergence of water/wildlife-associated Campylobacter jejuni niche specialists from common clonal complexes. Environ Microbiol 2011; 13:1549-60. [PMID: 21418497 PMCID: PMC3569610 DOI: 10.1111/j.1462-2920.2011.02461.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the major food-borne pathogen Campylobacter jejuni has been isolated from diverse animal, human and environmental sources, our knowledge of genomic diversity in C. jejuni is based exclusively on human or human food-chain-associated isolates. Studies employing multilocus sequence typing have indicated that some clonal complexes are more commonly associated with particular sources. Using comparative genomic hybridization on a collection of 80 isolates representing diverse sources and clonal complexes, we identified a separate clade comprising a group of water/wildlife isolates of C. jejuni with multilocus sequence types uncharacteristic of human food-chain-associated isolates. By genome sequencing one representative of this diverse group (C. jejuni 1336), and a representative of the bank-vole niche specialist ST-3704 (C. jejuni 414), we identified deletions of genomic regions normally carried by human food-chain-associated C. jejuni. Several of the deleted regions included genes implicated in chicken colonization or in virulence. Novel genomic insertions contributing to the accessory genomes of strains 1336 and 414 were identified. Comparative analysis using PCR assays indicated that novel regions were common but not ubiquitous among the water/wildlife group of isolates, indicating further genomic diversity among this group, whereas all ST-3704 isolates carried the same novel accessory regions. While strain 1336 was able to colonize chicks, strain 414 was not, suggesting that regions specifically absent from the genome of strain 414 may play an important role in this common route of Campylobacter infection of humans. We suggest that the genomic divergence observed constitutes evidence of adaptation leading to niche specialization.
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Affiliation(s)
- Philip J Hepworth
- Institute of Infection and Global Health Institute of Integrative Biology National Centre for Zoonosis Research, University of Liverpool, Liverpool L69 3GA, UK
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