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Loperena-Barber M, Elizalde-Bielsa A, Salvador-Bescós M, Ruiz-Rodríguez P, Pellegrini JM, Renau-Mínguez C, Lancaster R, Zúñiga-Ripa A, Iriarte M, Bengoechea JA, Coscollá M, Gorvel JP, Moriyón I, Conde-Álvarez R. "Phylogenomic insights into brucellaceae: The Pseudochrobactrum algeriensis case". INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 123:105625. [PMID: 38906517 DOI: 10.1016/j.meegid.2024.105625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/17/2024] [Accepted: 06/17/2024] [Indexed: 06/23/2024]
Abstract
The genus Pseudochrobactrum encompasses free-living bacteria phylogenetically close to Ochrobactrum opportunistic pathogens and to Brucella, facultative intracellular parasites causing brucellosis, a worldwide-extended and grave zoonosis. Recently, Pseudochrobactrum strains were isolated from Brucella natural hosts on Brucella selective media, potentially causing diagnostic confusions. Strikingly, P. algeriensis was isolated from cattle lymph nodes, organs that are inimical to bacteria. Here, we analyse P. algeriensis potential virulence factors in comparison with Ochrobactrum and Brucella. Consistent with genomic analyses, Western-Blot analyses confirmed that P. algeriensis lacks the ability to synthesize the N-formylperosamine O-polysaccharide characteristic of the lipopolysaccharide (LPS) of smooth Brucella core species. However, unlike other Pseudochrobactrum but similar to some early diverging brucellae, P. algeriensis carries genes potentially synthetizing a rhamnose-based O-polysaccharide LPS. Lipid A analysis by MALDI-TOF demonstrated that P. algeriensis LPS bears a lipid A with a reduced pathogen-associated molecular pattern, a trait shared with Ochrobactrum and Brucella that is essential to generate a highly stable outer membrane and to delay immune activation. Also, although not able to multiply intracellularly in macrophages, the analysis of P. algeriensis cell lipid envelope revealed the presence of large amounts of cationic aminolipids, which may account for the extremely high resistance of P. algeriensis to bactericidal peptides and could favor colonization of mucosae and transient survival in Brucella hosts. However, two traits critical in Brucella pathogenicity are either significantly different (T4SS [VirB]) or absent (erythritol catabolic pathway) in P. algeriensis. This work shows that, while diverging in other characteristics, lipidic envelope features relevant in Brucella pathogenicity are conserved in Brucellaceae. The constant presence of these features strongly suggests that reinforcement of the envelope integrity as an adaptive advantage in soil was maintained in Brucella because of the similarity of some environmental challenges, such as the action of cationic peptide antibiotics and host defense peptides. This information adds knowledge about the evolution of Brucellaceae, and also underlines the taxonomical differences of the three genera compared.
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Affiliation(s)
- Maite Loperena-Barber
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Aitor Elizalde-Bielsa
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Miriam Salvador-Bescós
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Paula Ruiz-Rodríguez
- Institute for Integrative Systems Biology, Universidad de Valencia-CSIC, Valencia, Spain
| | | | - Chantal Renau-Mínguez
- Institute for Integrative Systems Biology, Universidad de Valencia-CSIC, Valencia, Spain
| | - Rebecca Lancaster
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Amaia Zúñiga-Ripa
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Maite Iriarte
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Jose A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Mireia Coscollá
- Institute for Integrative Systems Biology, Universidad de Valencia-CSIC, Valencia, Spain
| | - Jean-Pierre Gorvel
- Centre d'Immunologie de Marseille-Luminy, CNRS, INSERM, Aix-Marseille University, Marseille, France
| | - Ignacio Moriyón
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Raquel Conde-Álvarez
- Instituto de Investigación Sanitaria de Navarra (IdISNA) and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain.
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Man L, Soh PXY, McEnearney TE, Cain JA, Dale AL, Cordwell SJ. Multi-Omics of Campylobacter jejuni Growth in Chicken Exudate Reveals Molecular Remodelling Associated with Altered Virulence and Survival Phenotypes. Microorganisms 2024; 12:860. [PMID: 38792690 PMCID: PMC11123243 DOI: 10.3390/microorganisms12050860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/15/2024] [Accepted: 04/22/2024] [Indexed: 05/26/2024] Open
Abstract
Campylobacter jejuni is the leading cause of foodborne human gastroenteritis in the developed world. Infections are largely acquired from poultry produced for human consumption and poor food handling is thus a major risk factor. Chicken exudate (CE) is a liquid produced from defrosted commercial chicken products that facilitates C. jejuni growth. We examined the response of C. jejuni to growth in CE using a multi-omics approach. Changes in the C. jejuni proteome were assessed by label-based liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). We quantified 1328 and 1304 proteins, respectively, in experiments comparing 5% CE in Mueller-Hinton (MH) medium and 100% CE with MH-only controls. These proteins represent 81.8% and 80.3% of the predicted C. jejuni NCTC11168 proteome. Growth in CE induced profound remodelling of the proteome. These changes were typically conserved between 5% and 100% CE, with a greater magnitude of change observed in 100% CE. We confirmed that CE induced C. jejuni biofilm formation, as well as increasing motility and resistance against oxidative stress, consistent with changes to proteins representing those functions. Assessment of the C. jejuni metabolome showed CE also led to increased intracellular abundances of serine, proline, and lactate that were correlated with the elevated abundances of their respective transporters. Analysis of carbon source uptake showed prolonged culture supernatant retention of proline and succinate in CE-supplemented medium. Metabolomics data provided preliminary evidence for the uptake of chicken-meat-associated dipeptides. C. jejuni exposed to CE showed increased resistance to several antibiotics, including polymyxin B, consistent with changes to tripartite efflux system proteins and those involved in the synthesis of lipid A. The C. jejuni CE proteome was also characterised by very large increases in proteins associated with iron acquisition, while a decrease in proteins containing iron-sulphur clusters was also observed. Our data suggest CE is both oxygen- and iron-limiting and provide evidence of factors required for phenotypic remodelling to enable C. jejuni survival on poultry products.
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Affiliation(s)
- Lok Man
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Pamela X. Y. Soh
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Tess E. McEnearney
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Joel A. Cain
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ashleigh L. Dale
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Stuart J. Cordwell
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
- Sydney Mass Spectrometry, The University of Sydney, Sydney, NSW 2006, Australia
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Yan R, M'ikanatha NM, Nachamkin I, Hudson LK, Denes TG, Kovac J. Prevalence of ciprofloxacin resistance and associated genetic determinants differed among Campylobacter isolated from human and poultry meat sources in Pennsylvania. Food Microbiol 2023; 116:104349. [PMID: 37689423 DOI: 10.1016/j.fm.2023.104349] [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: 07/08/2022] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 09/11/2023]
Abstract
Poultry is the primary source of Campylobacter infections and severe campylobacteriosis cases are treated with macrolides and fluoroquinolones. However, these drugs are less effective against antimicrobial-resistant strains. Here, we investigated the prevalence of phenotypic antimicrobial resistance and associated resistance genetic determinants in Campylobacter isolates collected from human clinical (N = 123) and meat (N = 80) sources in Pennsylvania in 2017 and 2018. Our goal was to assess potential differences in the prevalence of antimicrobial resistance in Campylobacter isolated from human and poultry meat sources in Pennsylvania and to assess the accuracy of predicting antimicrobial resistance phenotypes based on resistance genotypes. We whole genome sequenced isolates and identified genetic resistance determinants using the National Antimicrobial Resistance Monitoring System Campylobacter AMR workflow v2.0 in GalaxyTrakr. Phenotypic antimicrobial susceptibility testing was carried out using the E-Test and Sensititre CAMPYCMV methods for human clinical and poultry meat isolates, respectively, and the results were interpreted using the EUCAST epidemiological cutoff values. The 193 isolates were represented by 85 MLST sequence types and 23 clonal complexes, suggesting high genetic diversity. Resistance to erythromycin was confirmed in 6% human and 4% meat isolates. Prevalence of ciprofloxacin resistance was significantly higher in human isolates as compared to meat isolates. A good concordance was observed between phenotypic resistance and the presence of the corresponding known resistance genetic determinants.
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Affiliation(s)
- Runan Yan
- Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Irving Nachamkin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lauren K Hudson
- Department of Food Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Thomas G Denes
- Department of Food Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Jasna Kovac
- Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA.
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Valvano MA. Remodelling of the Gram-negative bacterial Kdo 2-lipid A and its functional implications. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35394417 DOI: 10.1099/mic.0.001159] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The lipopolysaccharide (LPS) is a characteristic molecule of the outer leaflet of the Gram-negative bacterial outer membrane, which consists of lipid A, core oligosaccharide, and O antigen. The lipid A is embedded in outer membrane and provides an efficient permeability barrier, which is particularly important to reduce the permeability of antibiotics, toxic cationic metals, and antimicrobial peptides. LPS, an important modulator of innate immune responses ranging from localized inflammation to disseminated sepsis, displays a high level of structural and functional heterogeneity, which arise due to regulated differences in the acylation of the lipid A and the incorporation of non-stoichiometric modifications in lipid A and the core oligosaccharide. This review focuses on the current mechanistic understanding of the synthesis and assembly of the lipid A molecule and its most salient non-stoichiometric modifications.
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Affiliation(s)
- Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7BL, UK
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Singh A, Khan A, Ghosh T, Mondal S, Mallick AI. Gut Microbe-Derived Outer Membrane Vesicles: A Potential Platform to Control Cecal Load of Campylobacter jejuni. ACS Infect Dis 2021; 7:1186-1199. [PMID: 33724795 DOI: 10.1021/acsinfecdis.0c00744] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Acute diarrheal illness and gastroenteritis caused by Campylobacter jejuni infection remain significant public health risks in developing countries with substantial mortality and morbidity in humans, particularly in children under the age of five. Genetic diversities among Campylobacter jejuni and limited understanding of immunological correlations of host protection remain primary impediments for developing an effective measure to controlCampylobacter infection. Moreover, the lack of a reliable in vivo model to mimic natural infection against Campylobacter jejuni has substantially delayed the vaccine-development process. Given the role of bacterial outer membrane associated proteins in intestinal adherence and invasion as well as modulating dynamic interplay between host and pathogens, bacterial outer-membrane vesicles have emerged as a potential vaccine target against a number of gut pathogens, including Campylobacter jejuni. Here, we describe a mucosal vaccine strategy using chitosan-coated outer-membrane vesicles to induce specific immune responses against Campylobacter jejuni in mice. To overcome the challenges of mucosal delivery of outer membrane vesicles in terms of exposure to variable pH and risk of enzymatic degradation, we preferentially used chitosan as a nontoxic, mucoadhesive polymer. We show that intragastric delivery of chitosan-coated outer-membrane vesicles imparts significant immune protection against Campylobacter jejuni with high level local and systemic antibody production. Further, immunization with the outer membrane vesicles resulted in potent cellular responses with an increased CD4+ and CD8+ T cell population. Moreover, significant upregulation of IFN-γ and IL-6 gene expression suggests that mucosal delivery of outer membrane vesicles promotes a Th1/Th2 mixed-type immune response. Together, as an acellular and nonreplicating canonical end product of bacterial secretion, mucosal delivery of outer membrane vesicles may represent a promising platform for developing an effective vaccine againstCampylobacter jejuni.
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Affiliation(s)
- Ankita Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246 West Bengal, India
| | - Afruja Khan
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246 West Bengal, India
| | - Tamal Ghosh
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246 West Bengal, India
| | - Samiran Mondal
- Department of Veterinary Pathology, West Bengal University of Animal and Fishery Sciences, Belgachia, Kolkata, 700037 West Bengal, India
| | - Amirul I. Mallick
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246 West Bengal, India
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Muszyński A, Zarember KA, Heiss C, Shiloach J, Berg LJ, Audley J, Kozyr A, Greenberg DE, Holland SM, Malech HL, Azadi P, Carlson RW, Gallin JI. Granulibacter bethesdensis, a Pathogen from Patients with Chronic Granulomatous Disease, Produces a Penta-Acylated Hypostimulatory Glycero-D-talo-oct-2-ulosonic Acid-Lipid A Glycolipid (Ko-Lipid A). Int J Mol Sci 2021; 22:3303. [PMID: 33804872 PMCID: PMC8036547 DOI: 10.3390/ijms22073303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022] Open
Abstract
Granulibacter bethesdensis can infect patients with chronic granulomatous disease, an immunodeficiency caused by reduced phagocyte NADPH oxidase function. Intact G. bethesdensis (Gb) is hypostimulatory compared to Escherichia coli, i.e., cytokine production in human blood requires 10-100 times more G. bethesdensis CFU/mL than E. coli. To better understand the pathogenicity of G. bethesdensis, we isolated its lipopolysaccharide (GbLPS) and characterized its lipid A. Unlike with typical Enterobacteriaceae, the release of presumptive Gb lipid A from its LPS required a strong acid. NMR and mass spectrometry demonstrated that the carbohydrate portion of the isolated glycolipid consists of α-Manp-(1→4)-β-GlcpN3N-(1→6)-α-GlcpN-(1⇿1)-α-GlcpA tetra-saccharide substituted with five acyl chains: the amide-linked N-3' 14:0(3-OH), N-2' 16:0(3-O16:0), and N-2 18:0(3-OH) and the ester-linked O-3 14:0(3-OH) and 16:0. The identification of glycero-d-talo-oct-2-ulosonic acid (Ko) as the first constituent of the core region of the LPS that is covalently attached to GlcpN3N of the lipid backbone may account for the acid resistance of GbLPS. In addition, the presence of Ko and only five acyl chains may explain the >10-fold lower proinflammatory potency of GbKo-lipidA compared to E. coli lipid A, as measured by cytokine induction in human blood. These unusual structural properties of the G.bethesdensis Ko-lipid A glycolipid likely contribute to immune evasion during pathogenesis and resistance to antimicrobial peptides.
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Affiliation(s)
- Artur Muszyński
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.H.); (P.A.); (R.W.C.)
| | - Kol A. Zarember
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - Christian Heiss
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.H.); (P.A.); (R.W.C.)
| | - Joseph Shiloach
- Biotechnology Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
| | - Lars J. Berg
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - John Audley
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - Arina Kozyr
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - David E. Greenberg
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - Steven M. Holland
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - Harry L. Malech
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.H.); (P.A.); (R.W.C.)
| | - Russell W. Carlson
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.H.); (P.A.); (R.W.C.)
| | - John I. Gallin
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (K.A.Z.); (L.J.B.); (J.A.); (A.K.); (D.E.G.); (S.M.H.); (H.L.M.)
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Kawahara K. Variation, Modification and Engineering of Lipid A in Endotoxin of Gram-Negative Bacteria. Int J Mol Sci 2021; 22:2281. [PMID: 33668925 PMCID: PMC7956469 DOI: 10.3390/ijms22052281] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/20/2021] [Accepted: 02/22/2021] [Indexed: 12/12/2022] Open
Abstract
Lipid A of Gram-negative bacteria is known to represent a central role for the immunological activity of endotoxin. Chemical structure and biosynthetic pathways as well as specific receptors on phagocytic cells had been clarified by the beginning of the 21st century. Although the lipid A of enterobacteria including Escherichia coli share a common structure, other Gram-negative bacteria belonging to various classes of the phylum Proteobacteria and other taxonomical groups show wide variety of lipid A structure with relatively decreased endotoxic activity compared to that of E. coli. The structural diversity is produced from the difference of chain length of 3-hydroxy fatty acids and non-hydroxy fatty acids linked to their hydroxyl groups. In some bacteria, glucosamine in the backbone is substituted by another amino sugar, or phosphate groups bound to the backbone are modified. The variation of structure is also introduced by the enzymes that can modify electrostatic charges or acylation profiles of lipid A during or after its synthesis. Furthermore, lipid A structure can be artificially modified or engineered by the disruption and introduction of biosynthetic genes especially those of acyltransferases. These technologies may produce novel vaccine adjuvants or antagonistic drugs derived from endotoxin in the future.
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Affiliation(s)
- Kazuyoshi Kawahara
- Department of Biosciences, College of Science and Engineering, Kanto Gakuin University, Yokohama, Kanagawa 236-8501, Japan
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Low-Dose Exposure to Ganglioside-Mimicking Bacteria Tolerizes Human Macrophages to Guillain-Barré Syndrome-Associated Antigens. mBio 2021; 13:e0385221. [PMID: 35100875 PMCID: PMC8805021 DOI: 10.1128/mbio.03852-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Early in life, commensal bacteria play a major role in immune development, helping to guide the host response toward harmful stimuli while tolerating harmless antigens to prevent autoimmunity. Guillain-Barré syndrome (GBS) is an autoimmune disease caused by errant immune attack of antibody-bound ganglioside receptors on host nerve cells, resulting in paralysis. Lipooligosaccharides enveloping the prevalent enteric pathogen, Campylobacter jejuni, frequently mimic human gangliosides and can trigger GBS by stimulating the autoimmune response. In low- to middle-income countries, young children are consistently exposed to C. jejuni, and it is not known if this impacts GBS susceptibility later in life. Using a macrophage model, we examined the effect of training these cells with low doses of ganglioside-mimicking bacteria prior to challenge with GBS-associated antigens. This training caused decreased production of proinflammatory cytokines, suggesting tolerance induction. We then screened Campylobacter isolates from 154 infant fecal samples for GM1 ganglioside mimicry, finding that 23.4% of strains from both symptomatic and asymptomatic infants displayed GM1-like structures. Training macrophages with one of these asymptomatic carrier isolates also induced tolerance against GBS-associated antigens, supporting that children can be exposed to the tolerizing antigen early in life. RNA interference of Toll-like receptor 2 (TLR2) and TLR4 suggests that these receptors are not involved in tolerance associated with decreases in tumor necrosis factor (TNF), interleukin-6 (IL-6), or IL-1β levels. The results of this study suggest that exposure to ganglioside-mimicking bacteria early in life occurs naturally and impacts host susceptibility to GBS development. IMPORTANCE In this study, we demonstrated that it is possible to tolerize immune cells to potentially dampen the autoreactive proinflammatory immune response against Guillain-Barré syndrome (GBS)-associated antigens. The innate immune response functions to arm the host against bacterial attack, but it can be tricked into recognizing the host's own cells when infectious bacteria display sugar structures that mimic human glycans. It is this errant response that leads to the autoimmunity and paralysis associated with GBS. By presenting immune cells with small amounts of the bacterial glycan mimic, we were able to suppress the proinflammatory immune response upon subsequent high exposure to glycan-mimicking bacteria. This suggests that individuals who have already been exposed to the glycan mimics in small amounts are less sensitive to autoimmune reactions against these glycans, and this could be a factor in determining susceptibility to GBS.
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9
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Mousavi S, Bereswill S, Heimesaat MM. Murine Models for the Investigation of Colonization Resistance and Innate Immune Responses in Campylobacter Jejuni Infections. Curr Top Microbiol Immunol 2021; 431:233-263. [PMID: 33620654 DOI: 10.1007/978-3-030-65481-8_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human infections with the food-borne pathogen Campylobacter jejuni are progressively increasing worldwide and constitute a significant socioeconomic burden to mankind. Intestinal campylobacteriosis in humans is characterized by bloody diarrhea, fever, abdominal pain, and severe malaise. Some individuals develop chronic post-infectious sequelae including neurological and autoimmune diseases such as reactive arthritis and Guillain-Barré syndrome. Studies unraveling the molecular mechanisms underlying campylobacteriosis and post-infectious sequelae have been hampered by the scarcity of appropriate experimental in vivo models. Particularly, conventional laboratory mice are protected from C. jejuni infection due to the physiological colonization resistance exerted by the murine gut microbiota composition. Additionally, as compared to humans, mice are up to 10,000 times more resistant to C. jejuni lipooligosaccharide (LOS) constituting a major pathogenicity factor responsible for the immunopathological host responses during campylobacteriosis. In this chapter, we summarize the recent progress that has been made in overcoming these fundamental obstacles in Campylobacter research in mice. Modification of the murine host-specific gut microbiota composition and sensitization of the mice to C. jejuni LOS by deletion of genes encoding interleukin-10 or a single IL-1 receptor-related molecule as well as by dietary zinc depletion have yielded reliable murine infection models resembling key features of human campylobacteriosis. These substantial improvements pave the way for a better understanding of the molecular mechanisms underlying pathogen-host interactions. The ongoing validation and standardization of these novel murine infection models will provide the basis for the development of innovative treatment and prevention strategies to combat human campylobacteriosis and collateral damages of C. jejuni infections.
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Affiliation(s)
- Soraya Mousavi
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité-University Medicine Berlin, Corporate Member of Free University Berlin, Humboldt-University of Berlin, Berlin Institute of Health, Berlin, Germany
| | - Stefan Bereswill
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité-University Medicine Berlin, Corporate Member of Free University Berlin, Humboldt-University of Berlin, Berlin Institute of Health, Berlin, Germany
| | - Markus M Heimesaat
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité-University Medicine Berlin, Corporate Member of Free University Berlin, Humboldt-University of Berlin, Berlin Institute of Health, Berlin, Germany.
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10
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Manissorn J, Sitthiyotha T, Montalban JRE, Chunsrivirot S, Thongnuek P, Wangkanont K. Biochemical and Structural Investigation of GnnA in the Lipopolysaccharide Biosynthesis Pathway of Acidithiobacillus ferrooxidans. ACS Chem Biol 2020; 15:3235-3243. [PMID: 33200610 DOI: 10.1021/acschembio.0c00791] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Lipopolysaccharide (LPS) is a crucial component in the outer membrane of Gram-negative bacteria that contributes to both pathogenicity as well as immunity against pathogenic bacteria. Typical LPS contains GlcN disaccharide as the core of lipid A. However, some bacteria such as Acidithiobacillus ferrooxidans and Leptospira interrogans contain GlcN3N in lipid A instead. This modification has been shown to dampen the host immune response and increase resistance to antimicrobial peptides. Therefore, investigation of the enzymes responsible for the biosynthesis of GlcN3N has promising applications in the development of vaccines, antibiotics, or usage of the enzymes in chemoenzymatic synthesis of modified LPS. Here, we describe biochemical and structural investigation of GnnA from A. ferrooxidans (AfGnnA) that is responsible for oxidation of UDP-GlcNAc, which subsequently undergoes transamination to produce UDP-GlcNAc3N as a precursor for LPS biosynthesis. AfGnnA is specific for NAD+ and UDP-GlcNAc. The crystal structures of AfGnnA in combination with molecular dynamics simulation and mutational analysis suggest the substrate recognition mode and the catalytic mechanism. K91 or H164 is a potential catalytic base in the oxidation reaction. The results will not only provide insights into the biosynthesis of unusual LPS but will also lay the foundation for development of more immunogenic vaccines, novel antibiotics, or utilization of GnnA in the synthesis of UDP-sugars or modified LPS.
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Affiliation(s)
- Juthatip Manissorn
- Biomedical Engineering Research Center (BMERC) and Biomedical Engineering Program, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Thassanai Sitthiyotha
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Jenny Rose E. Montalban
- Department of Biochemistry, Faculty of Pharmacy, University of Santo Tomas, Manila 1008, Philippines
| | - Surasak Chunsrivirot
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Peerapat Thongnuek
- Biomedical Engineering Research Center (BMERC) and Biomedical Engineering Program, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Kittikhun Wangkanont
- Center of Excellence for Molecular Biology and Genomics of Shrimp, and Molecular Crop Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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Toll-Like Receptor-4 Is Involved in Mediating Intestinal and Extra-Intestinal Inflammation in Campylobacter coli-Infected Secondary Abiotic IL-10 -/- Mice. Microorganisms 2020; 8:microorganisms8121882. [PMID: 33261211 PMCID: PMC7761268 DOI: 10.3390/microorganisms8121882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 01/01/2023] Open
Abstract
Human Campylobacter infections are emerging worldwide and constitute significant health burdens. We recently showed that the immunopathological sequelae in Campylobacter jejuni-infected mice were due to Toll-like receptor (TLR)-4 dependent immune responses induced by bacterial lipooligosaccharide (LOS). Information regarding the molecular mechanisms underlying Campylobacter coli-host interactions are scarce, however. Therefore, we analyzed C. coli-induced campylobacteriosis in secondary abiotic IL-10−/− mice with and without TLR4. Mice were infected perorally with a human C. coli isolate or with a murine commensal Escherichia coli as apathogenic, non-invasive control. Independent from TLR4, C. coli and E. coli stably colonized the gastrointestinal tract, but only C. coli induced clinical signs of campylobacteriosis. TLR4−/− IL-10−/− mice, however, displayed less frequently fecal blood and less distinct histopathological and apoptotic sequelae in the colon versus IL-10−/− counterparts on day 28 following C. coli infection. Furthermore, C. coli-induced colonic immune cell responses were less pronounced in TLR4−/− IL-10−/− as compared to IL-10−/− mice and accompanied by lower pro-inflammatory mediator concentrations in the intestines and the liver of the former versus the latter. In conclusion, our study provides evidence that TLR4 is involved in mediating C. coli-LOS-induced immune responses in intestinal and extra-intestinal compartments during murine campylobacteriosis.
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12
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Mousavi S, Bereswill S, Heimesaat MM. Novel Clinical Campylobacter jejuni Infection Models Based on Sensitization of Mice to Lipooligosaccharide, a Major Bacterial Factor Triggering Innate Immune Responses in Human Campylobacteriosis. Microorganisms 2020; 8:E482. [PMID: 32231139 PMCID: PMC7232424 DOI: 10.3390/microorganisms8040482] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 12/12/2022] Open
Abstract
: Human Campylobacter jejuni infections inducing campylobacteriosis including post-infectious sequelae such as Guillain-Barré syndrome and reactive arthritis are rising worldwide and progress into a global burden of high socioeconomic impact. Intestinal immunopathology underlying campylobacteriosis is a classical response of the innate immune system characterized by the accumulation of neutrophils and macrophages which cause tissue destruction, barrier defects and malabsorption leading to bloody diarrhea. Clinical studies revealed that enteritis and post-infectious morbidities of human C. jejuni infections are strongly dependent on the structure of pathogenic lipooligosaccharides (LOS) triggering the innate immune system via Toll-like-receptor (TLR)-4 signaling. Compared to humans, mice display an approximately 10,000 times weaker TLR-4 response and a pronounced colonization resistance (CR) against C. jejuni maintained by the murine gut microbiota. In consequence, investigations of campylobacteriosis have been hampered by the lack of experimental animal models. We here summarize recent progress made in the development of murine C. jejuni infection models that are based on the abolishment of CR by modulating the murine gut microbiota and by sensitization of mice to LOS. These advances support the major role of LOS driven innate immunity in pathogenesis of campylobacteriosis including post-infectious autoimmune diseases and promote the preclinical evaluation of novel pharmaceutical strategies for prophylaxis and treatment.
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13
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Simpson BW, Trent MS. Pushing the envelope: LPS modifications and their consequences. Nat Rev Microbiol 2020; 17:403-416. [PMID: 31142822 DOI: 10.1038/s41579-019-0201-x] [Citation(s) in RCA: 263] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The defining feature of the Gram-negative cell envelope is the presence of two cellular membranes, with the specialized glycolipid lipopolysaccharide (LPS) exclusively found on the surface of the outer membrane. The surface layer of LPS contributes to the stringent permeability properties of the outer membrane, which is particularly resistant to permeation of many toxic compounds, including antibiotics. As a common surface antigen, LPS is recognized by host immune cells, which mount defences to clear pathogenic bacteria. To alter properties of the outer membrane or evade the host immune response, Gram-negative bacteria chemically modify LPS in a wide variety of ways. Here, we review key features and physiological consequences of LPS biogenesis and modifications.
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Affiliation(s)
- Brent W Simpson
- Department of Infectious Diseases, University of Georgia, Athens, GA, USA
| | - M Stephen Trent
- Department of Infectious Diseases, University of Georgia, Athens, GA, USA. .,Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA. .,Department of Microbiology, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA.
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14
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Structure and inflammatory activity of the LPS isolated from Acetobacter pasteurianus CIP103108. Int J Biol Macromol 2018; 119:1027-1035. [PMID: 30098357 DOI: 10.1016/j.ijbiomac.2018.08.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 12/30/2022]
Abstract
Acetobacter pasteurianus is an acetic acid-producing Gram-negative bacterium commonly found associated with plants and plant products and widely used in the production of fermented foods, such as kefir and vinegar. Due to the acid conditions of the bacterium living habitat, uncommon structural features composing its cell envelope are expected. In the present work we have investigated the A. pasteurianus CIP103108 lipopolysaccharide (LPS) structure and immunoactivity. The structure of the lipid A and of two different O-polysaccharides was assessed. Furthermore, immunological studies with human cells showed a low immunostimulant activity of the isolated LPS, in addition to a slight capability to lower the NF-kB activation upon stimulation by toxic LPS.
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15
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Brunner K, John CM, Phillips NJ, Alber DG, Gemmell MR, Hansen R, Nielsen HL, Hold GL, Bajaj-Elliott M, Jarvis GA. Novel Campylobacter concisus lipooligosaccharide is a determinant of inflammatory potential and virulence. J Lipid Res 2018; 59:1893-1905. [PMID: 30049709 DOI: 10.1194/jlr.m085860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/29/2018] [Indexed: 12/15/2022] Open
Abstract
The pathogenicity of Campylobacter concisus, increasingly found in the human gastrointestinal (GI) tract, is unclear. Some studies indicate that its role in GI conditions has been underestimated, whereas others suggest that the organism has a commensal-like phenotype. For the enteropathogen C. jejuni, the lipooligosaccharide (LOS) is a main driver of virulence. We investigated the LOS structure of four C. concisus clinical isolates and correlated the inflammatory potential of each isolate with bacterial virulence. Mass spectrometric analyses of lipid A revealed a novel hexa-acylated diglucosamine moiety with two or three phosphoryl substituents. Molecular and fragment ion analysis indicated that the oligosaccharide portion of the LOS had only a single phosphate and lacked phosphoethanolamine and sialic acid substitution, which are hallmarks of the C. jejuni LOS. Consistent with our structural findings, C. concisus LOS and live bacteria induced less TNF-α secretion in human monocytes than did C. jejuni Furthermore, the C. concisus bacteria were less virulent than C. jejuni in a Galleria mellonella infection model. The correlation of the novel lipid A structure, decreased phosphorylation, and lack of sialylation along with reduced inflammatory potential and virulence support the significance of the LOS as a determinant in the relative pathogenicity of C. concisus.
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Affiliation(s)
- Katja Brunner
- Infection, Immunity and Inflammation Programme, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Constance M John
- Center for Immunochemistry, Veterans Affairs Medical Center, San Francisco, CA.,Department of Laboratory Medicine University of California, San Francisco, CA
| | - Nancy J Phillips
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA
| | - Dagmar G Alber
- Infection, Immunity and Inflammation Programme, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Matthew R Gemmell
- Center for Genome-Enabled Biology and Medicine, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Richard Hansen
- Department of Paediatric Gastroenterology, Royal Hospital for Children, Glasgow, United Kingdom
| | - Hans L Nielsen
- Department of Infectious Diseases Aalborg University Hospital, Aalborg, Denmark.,Department of Clinical Microbiology, Aalborg University Hospital, Aalborg, Denmark
| | - Georgina L Hold
- St George and Sutherland Clinical School, University of New South Wales, Sydney, Australia
| | - Mona Bajaj-Elliott
- Infection, Immunity and Inflammation Programme, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Gary A Jarvis
- Center for Immunochemistry, Veterans Affairs Medical Center, San Francisco, CA .,Department of Laboratory Medicine University of California, San Francisco, CA
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16
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de Castro Burbarelli MF, do Valle Polycarpo G, Deliberali Lelis K, Granghelli CA, Carão de Pinho AC, Ribeiro Almeida Queiroz S, Fernandes AM, Moro de Souza RL, Gaglianone Moro ME, de Andrade Bordin R, de Albuquerque R. Cleaning and disinfection programs against Campylobacter jejuni for broiler chickens: productive performance, microbiological assessment and characterization. Poult Sci 2018; 96:3188-3198. [PMID: 28854757 PMCID: PMC5850738 DOI: 10.3382/ps/pex153] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 05/10/2017] [Indexed: 12/14/2022] Open
Abstract
Detailed cleaning and disinfection programs aims to reduce infection pressure from microorganisms from one flock to the next. However, studies evaluating the benefits to poultry performance, the sanitary status of the facilities, and the sanitary quality of the meat are rarely found. Thus, this study was designed to evaluate 2 cleaning and disinfecting programs regarding their influence on productive performance, elimination of Campylobacter, and characterization of Campylobacter jejuni strains when applied to broiler chickens’ facilities. Two subsequent flocks with 960 birds each were distributed into 32 pens containing 30 birds each. In the first, the whole flock was inoculated with a known strain of Campylobacter jejuni in order to contaminate the environment. In the second flock, performance and microbiological evaluations were done, characterizing an observational study between 2 cleaning and disinfection programs, regular and proposed. The regular program consisted of sweeping facilities, washing equipment and environment with water and neutral detergent. The proposed cleaning program consisted of dry and wet cleaning, application of 2 detergents (one acid and one basic) and 2 disinfectants (250 g/L glutaraldehyde and 185 g/L formaldehyde at 0.5% and 210 g/L para-chloro-meta-cresol at 4%). Total microorganism count in the environment and Campylobacter spp. identification were done for the microbiological assessment of the environment and carcasses. The positive samples were submitted to molecular identification of Campylobacter spp. and posterior genetic sequencing of the species identified as Campylobacter jejuni. The birds housed in the facilities and submitted to the proposed treatment had better performance when compared to the ones in the regular treatment, most likely because there was a smaller total microorganism count on the floor, walls, feeders and drinkers. The proposed program also resulted in a reduction of Campylobacter spp. on floors, drinkers and birds. Moreover, it was possible to identify 6 different Campylobacter jejuni strains in the facilities. The proposed treatment resulted in a positive influence on the birds’ performance and reduction of environment contamination for broiler chickens.
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Affiliation(s)
- Maria Fernanda de Castro Burbarelli
- Department of Animal Nutrition and Production (VNP), Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FMVZ-USP), Pirassununga, Brazil.
| | | | - Karoline Deliberali Lelis
- Department of Animal Nutrition and Production (VNP), Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FMVZ-USP), Pirassununga, Brazil
| | - Carlos Alexandre Granghelli
- Department of Animal Nutrition and Production (VNP), Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FMVZ-USP), Pirassununga, Brazil
| | - Agatha Cristina Carão de Pinho
- Department of Animal Nutrition and Production (VNP), Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FMVZ-USP), Pirassununga, Brazil
| | - Sabrina Ribeiro Almeida Queiroz
- Department of Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FZEA-USP), Pirassununga, Brazil
| | - Andrezza Maria Fernandes
- Department of Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FZEA-USP), Pirassununga, Brazil
| | - Ricardo Luiz Moro de Souza
- Department of Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FZEA-USP), Pirassununga, Brazil
| | - Maria Estela Gaglianone Moro
- Department of Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FZEA-USP), Pirassununga, Brazil
| | | | - Ricardo de Albuquerque
- Department of Animal Nutrition and Production (VNP), Faculty of Veterinary Medicine and Animal Science, University of São Paulo (FMVZ-USP), Pirassununga, Brazil
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17
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Kim S, Vela A, Clohisey SM, Athanasiadou S, Kaiser P, Stevens MP, Vervelde L. Host-specific differences in the response of cultured macrophages to Campylobacter jejuni capsule and O-methyl phosphoramidate mutants. Vet Res 2018; 49:3. [PMID: 29316981 PMCID: PMC5759256 DOI: 10.1186/s13567-017-0501-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 12/15/2017] [Indexed: 01/10/2023] Open
Abstract
Campylobacter jejuni is the leading cause of bacterial food-borne gastroenteritis worldwide and human infections are frequently associated with handling and consumption of contaminated poultry. The polysaccharide capsule of C. jejuni plays important roles in colonisation of the chicken gut, invasion of epithelial cells and serum resistance and is subject to modification with O-methyl phosphoramidate (MeOPN) in most strains. In this study, the cytokine responses of mouse bone marrow-derived macrophages (mBMMs), chicken bone marrow-derived macrophages (chBMMs) and human monocyte-derived macrophages (hMDMs) were measured following infection with C. jejuni 11168H wild-type (WT) or isogenic mutants lacking either the capsule (Δcj1439) or its MeOPN modification (Δcj1417). Consistent with previous observations using murine bone marrow-derived dendritic cells, mutants lacking the capsule or MeOPN elicited enhanced transcription of IL-6 and IL-10 in mBMMs compared to wild-type C. jejuni. However, the lack of capsule and MeOPN did not alter IL-6 and IL-10 expression in chBMMs and hMDMs compared to C. jejuni WT. Phagocytosis assays showed the acapsular mutant was not impaired in uptake or net intracellular survival after phagocytosis in both chicken and human macrophages; however, the phagocytosis of the MeOPN mutant was significantly decreased in both chicken and human macrophages. In conclusion, differences in the response of macrophages of varying host origin to Campylobacter were detected. The absence of MeOPN modification on the capsule of C. jejuni did not alter the levels of innate cytokine expression in both chicken and human macrophages compared to the 11168H WT, but affected phagocytosis by host macrophages.
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Affiliation(s)
- Sungwon Kim
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Andrea Vela
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Sara M Clohisey
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | | | - Pete Kaiser
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Mark P Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Lonneke Vervelde
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
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18
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Lipid A structural modifications in extreme conditions and identification of unique modifying enzymes to define the Toll-like receptor 4 structure-activity relationship. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1439-1450. [PMID: 28108356 DOI: 10.1016/j.bbalip.2017.01.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 01/23/2023]
Abstract
Strategies utilizing Toll-like receptor 4 (TLR4) agonists for treatment of cancer, infectious diseases, and other targets report promising results. Potent TLR4 antagonists are also gaining attention as therapeutic leads. Though some principles for TLR4 modulation by lipid A have been described, a thorough understanding of the structure-activity relationship (SAR) is lacking. Only through a complete definition of lipid A-TLR4 SAR is it possible to predict TLR4 signaling effects of discrete lipid A structures, rendering them more pharmacologically relevant. A limited 'toolbox' of lipid A-modifying enzymes has been defined and is largely composed of enzymes from mesophile human and zoonotic pathogens. Expansion of this 'toolbox' will result from extending the search into lipid A biosynthesis and modification by bacteria living at the extremes. Here, we review the fundamentals of lipid A structure, advances in lipid A uses in TLR4 modulation, and the search for novel lipid A-modifying systems in extremophile bacteria. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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19
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Culebro A, Revez J, Pascoe B, Friedmann Y, Hitchings MD, Stupak J, Sheppard SK, Li J, Rossi M. Large Sequence Diversity within the Biosynthesis Locus and Common Biochemical Features of Campylobacter coli Lipooligosaccharides. J Bacteriol 2016; 198:2829-40. [PMID: 27481928 PMCID: PMC5038013 DOI: 10.1128/jb.00347-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/23/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Despite the importance of lipooligosaccharides (LOSs) in the pathogenicity of campylobacteriosis, little is known about the genetic and phenotypic diversity of LOS in Campylobacter coli In this study, we investigated the distribution of LOS locus classes among a large collection of unrelated C. coli isolates sampled from several different host species. Furthermore, we paired C. coli genomic information and LOS chemical composition for the first time to investigate possible associations between LOS locus class sequence diversity and biochemical heterogeneity. After identifying three new LOS locus classes, only 85% of the 144 isolates tested were assigned to a class, suggesting higher genetic diversity than previously thought. This genetic diversity is at the basis of a completely unexplored LOS structural heterogeneity. Mass spectrometry analysis of the LOSs of nine isolates, representing four different LOS classes, identified two features distinguishing C. coli LOS from that of Campylobacter jejuni 2-Amino-2-deoxy-d-glucose (GlcN)-GlcN disaccharides were present in the lipid A backbone, in contrast to the β-1'-6-linked 3-diamino-2,3-dideoxy-d-glucopyranose (GlcN3N)-GlcN backbone observed in C. jejuni Moreover, despite the fact that many of the genes putatively involved in 3-acylamino-3,6-dideoxy-d-glucose (Quip3NAcyl) were apparently absent from the genomes of various isolates, this rare sugar was found in the outer core of all C. coli isolates. Therefore, regardless of the high genetic diversity of the LOS biosynthesis locus in C. coli, we identified species-specific phenotypic features of C. coli LOS that might explain differences between C. jejuni and C. coli in terms of population dynamics and host adaptation. IMPORTANCE Despite the importance of C. coli to human health and its controversial role as a causative agent of Guillain-Barré syndrome, little is known about the genetic and phenotypic diversity of C. coli LOSs. Therefore, we paired C. coli genomic information and LOS chemical composition for the first time to address this paucity of information. We identified two species-specific phenotypic features of C. coli LOS, which might contribute to elucidating the reasons behind the differences between C. jejuni and C. coli in terms of population dynamics and host adaptation.
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Affiliation(s)
- Alejandra Culebro
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Joana Revez
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Ben Pascoe
- College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Yasmin Friedmann
- College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom
| | - Matthew D Hitchings
- College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom
| | - Jacek Stupak
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada
| | - Samuel K Sheppard
- College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Jianjun Li
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada
| | - Mirko Rossi
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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20
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Trimble MJ, Mlynárčik P, Kolář M, Hancock REW. Polymyxin: Alternative Mechanisms of Action and Resistance. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025288. [PMID: 27503996 DOI: 10.1101/cshperspect.a025288] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antibiotic resistance among pathogenic bacteria is an ever-increasing issue worldwide. Unfortunately, very little has been achieved in the pharmaceutical industry to combat this problem. This has led researchers and the medical field to revisit past drugs that were deemed too toxic for clinical use. In particular, the cyclic cationic peptides polymyxin B and colistin, which are specific for Gram-negative bacteria, have been used as "last resort" antimicrobials. Before the 1980s, these drugs were known for their renal and neural toxicities; however, new clinical practices and possibly improved manufacturing have made them safer to use. Previously suggested to primarily attack the membranes of Gram-negative bacteria and to not easily select for resistant mutants, recent research exploring resistance and mechanisms of action has provided new perspectives. This review focuses primarily on the proposed alternative mechanisms of action, known resistance mechanisms, and how these support the alternative mechanisms of action.
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Affiliation(s)
- Michael J Trimble
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Patrik Mlynárčik
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Milan Kolář
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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21
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Novel Immunomodulatory Flagellin-Like Protein FlaC in Campylobacter jejuni and Other Campylobacterales. mSphere 2015; 1:mSphere00028-15. [PMID: 27303676 PMCID: PMC4863622 DOI: 10.1128/msphere.00028-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 10/28/2015] [Indexed: 11/24/2022] Open
Abstract
Flagellins not only are important for bacterial motility but are major bacterial proteins that can modulate host responses via Toll-like receptor 5 (TLR5) or other pattern recognition receptors. Campylobacterales colonizing the intestinal tracts of different host species harbor a gene coding for an unusual flagellin, FlaC, that is not involved in motility but is secreted and possesses a chimeric amino acid sequence composed of TLR5-activating and non-TLR5-activating flagellin sequences. Campylobacter jejuni FlaC activates cells to increase in cytokine expression in chicken and human cells, promotes cross-tolerance to TLR4 ligands, and alters chicken cecal microbiota. We propose that FlaC is a secreted effector flagellin that has specifically evolved to modulate the immune response in the intestinal tract in the presence of the resident microbiota and may contribute to bacterial persistence. The results also strengthen the role of the flagellar type III apparatus as a functional secretion system for bacterial effector proteins. The human diarrheal pathogens Campylobacter jejuni and Campylobacter coli interfere with host innate immune signaling by different means, and their flagellins, FlaA and FlaB, have a low intrinsic property to activate the innate immune receptor Toll-like receptor 5 (TLR5). We have investigated here the hypothesis that the unusual secreted, flagellin-like molecule FlaC present in C. jejuni, C. coli, and other Campylobacterales might activate cells via TLR5 and interact with TLR5. FlaC shows striking sequence identity in its D1 domains to TLR5-activating flagellins of other bacteria, such as Salmonella, but not to nonstimulating Campylobacter flagellins. We overexpressed and purified FlaC and tested its immunostimulatory properties on cells of human and chicken origin. Treatment of cells with highly purified FlaC resulted in p38 activation. FlaC directly interacted with TLR5. Preincubation with FlaC decreased the responsiveness of chicken and human macrophage-like cells toward the bacterial TLR4 agonist lipopolysaccharide (LPS), suggesting that FlaC mediates cross-tolerance. C. jejuni flaC mutants induced an increase of cell responses in comparison to those of the wild type, which was suppressed by genetic complementation. Supplementing excess purified FlaC likewise reduced the cellular response to C. jejuni. In vivo, the administration of ultrapure FlaC led to a decrease in cecal interleukin 1β (IL-1β) expression and a significant change of the cecal microbiota in chickens. We propose that Campylobacter spp. have evolved a novel type of secreted immunostimulatory flagellin-like effector in order to specifically modulate host responses, for example toward other pattern recognition receptor (PRR) ligands, such as LPS. IMPORTANCE Flagellins not only are important for bacterial motility but are major bacterial proteins that can modulate host responses via Toll-like receptor 5 (TLR5) or other pattern recognition receptors. Campylobacterales colonizing the intestinal tracts of different host species harbor a gene coding for an unusual flagellin, FlaC, that is not involved in motility but is secreted and possesses a chimeric amino acid sequence composed of TLR5-activating and non-TLR5-activating flagellin sequences. Campylobacter jejuni FlaC activates cells to increase in cytokine expression in chicken and human cells, promotes cross-tolerance to TLR4 ligands, and alters chicken cecal microbiota. We propose that FlaC is a secreted effector flagellin that has specifically evolved to modulate the immune response in the intestinal tract in the presence of the resident microbiota and may contribute to bacterial persistence. The results also strengthen the role of the flagellar type III apparatus as a functional secretion system for bacterial effector proteins.
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Lohans CT, van Belkum MJ, Li J, Vederas JC. Characterization of bacterial antimicrobial peptides active against Campylobacter jejuni. CAN J CHEM 2015. [DOI: 10.1139/cjc-2014-0411] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Campylobacter jejuni is one of the major causes of food poisoning, often resulting from the consumption of improperly cooked poultry products. The emergence of C. jejuni strains resistant to conventional antibiotics necessitates the evaluation of other possible treatments or preventative measures to minimize the impact and prevalence of infections. Antimicrobial peptides produced by bacteria have begun to emerge as a potential means of decreasing the levels of C. jejuni in poultry, thereby limiting Campylobacter contamination in associated food products. A number of bacteriocins produced by Gram-positive bacteria have unexpectedly been described as having antimicrobial activity against the Gram-negative C. jejuni. Additionally, some nonribosomal lipopeptides produced by Bacillus and Paenibacillus spp. show efficacy against this pathogen. This review will describe the bacterial antimicrobial peptides reported to be active against C. jejuni, with an emphasis on the characterization of their primary structures. However, for many of these peptides, little is known about their amino acid sequences and structures. Furthermore, there are unusual inconsistencies associated with the reported amino acid sequences for several of the more well-studied bacteriocins. Clarifying the chemical nature of these promising antimicrobial peptides is necessary before their potential utility for livestock protection from C. jejuni can be fully explored. Once these peptides are better characterized, they may prove to be strong candidates for minimizing the impact of Campylobacter on human health.
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Affiliation(s)
- Christopher T. Lohans
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - Marco J. van Belkum
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - Jing Li
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - John C. Vederas
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
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Varbanets LD. Glycopolymers of microorganisms: Achievements and future research (review). APPL BIOCHEM MICRO+ 2014. [DOI: 10.1134/s0003683814060143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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24
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The lipopolysaccharide modification regulator PmrA limits Salmonella virulence by repressing the type three-secretion system Spi/Ssa. Proc Natl Acad Sci U S A 2013; 110:9499-504. [PMID: 23690578 DOI: 10.1073/pnas.1303420110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The regulatory protein PmrA controls expression of lipopolysaccharide (LPS) modification genes in Salmonella enterica serovar Typhimurium, the etiologic agent of human gastroenteritis and murine typhoid fever. PmrA-dependent LPS modifications confer resistance to serum, Fe(3+), and several antimicrobial peptides, suggesting that the pmrA gene is required for Salmonella virulence. We now report that, surprisingly, a pmrA null mutant is actually hypervirulent when inoculated i.p. into C3H/HeN mice. We establish that the PmrA protein binds to the promoter and represses transcription of ssrB, a virulence regulatory gene required for expression of the Spi/Ssa type three-secretion system inside macrophages. The pmrA mutant displayed heightened expression of SsrB-dependent genes and faster Spi/Ssa-dependent macrophage killing than wild-type Salmonella. A mutation in the ssrB promoter that abolished repression by the PmrA protein rendered Salmonella as hypervirulent as the pmrA null mutant. The antivirulence function of the PmrA protein may limit the acute phase of Salmonella infection, thereby enhancing pathogen persistence in host tissues.
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25
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Stephenson HN, John CM, Naz N, Gundogdu O, Dorrell N, Wren BW, Jarvis GA, Bajaj-Elliott M. Campylobacter jejuni lipooligosaccharide sialylation, phosphorylation, and amide/ester linkage modifications fine-tune human Toll-like receptor 4 activation. J Biol Chem 2013; 288:19661-72. [PMID: 23629657 DOI: 10.1074/jbc.m113.468298] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Campylobacter jejuni is a leading cause of acute gastroenteritis. C. jejuni lipooligosaccharide (LOS) is a potent activator of Toll-like receptor (TLR) 4-mediated innate immunity. Structural variations of the LOS have been previously reported in the oligosaccharide (OS) moiety, the disaccharide lipid A (LA) backbone, and the phosphorylation of the LA. Here, we studied LOS structural variation between C. jejuni strains associated with different ecological sources and analyzed their ability to activate TLR4 function. MALDI-TOF MS was performed to characterize structural variation in both the OS and LA among 15 different C. jejuni isolates. Cytokine induction in THP-1 cells and primary monocytes was correlated with LOS structural variation in each strain. Additionally, structural variation was correlated with the source of each strain. OS sialylation, increasing abundance of LA d-glucosamine versus 2,3-diamino-2,3-dideoxy-d-glucose, and phosphorylation status all correlated with TLR4 activation as measured in THP-1 cells and monocytes. Importantly, LOS-induced inflammatory responses were similar to those elicited by live bacteria, highlighting the prominent contribution of the LOS component in driving host immunity. OS sialylation status but not LA structure showed significant association with strains clustering with livestock sources. Our study highlights how variations in three structural components of C. jejuni LOS alter TLR4 activation and consequent monocyte activation.
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Affiliation(s)
- Holly N Stephenson
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, United Kingdom
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Maue AC, Mohawk KL, Giles DK, Poly F, Ewing CP, Jiao Y, Lee G, Ma Z, Monteiro MA, Hill CL, Ferderber JS, Porter CK, Trent MS, Guerry P. The polysaccharide capsule of Campylobacter jejuni modulates the host immune response. Infect Immun 2013; 81:665-72. [PMID: 23250948 PMCID: PMC3584872 DOI: 10.1128/iai.01008-12] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 12/05/2012] [Indexed: 12/22/2022] Open
Abstract
Campylobacter jejuni is a major cause of bacterial diarrheal disease worldwide. The organism is characterized by a diversity of polysaccharide structures, including a polysaccharide capsule. Most C. jejuni capsules are known to be decorated nonstoichiometrically with methyl phosphoramidate (MeOPN). The capsule of C. jejuni 81-176 has been shown to be required for serum resistance, but here we show that an encapsulated mutant lacking the MeOPN modification, an mpnC mutant, was equally as sensitive to serum killing as the nonencapsulated mutant. A nonencapsulated mutant, a kpsM mutant, exhibited significantly reduced colonization compared to that of wild-type 81-176 in a mouse intestinal colonization model, and the mpnC mutant showed an intermediate level of colonization. Both mutants were associated with higher levels of interleukin 17 (IL-17) expression from lamina propria CD4(+) cells than from cells from animals infected with 81-176. In addition, reduced levels of Toll-like receptor 4 (TLR4) and TLR2 activation were observed following in vitro stimulation of human reporter cell lines with the kpsM and mpnC mutants compared to those with wild-type 81-176. The data suggest that the capsule polysaccharide of C. jejuni and the MeOPN modification modulate the host immune response.
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Affiliation(s)
- Alexander C. Maue
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Krystle L. Mohawk
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - David K. Giles
- Department of Biological and Environmental Sciences, University of Tennessee at Chattanooga, Chattagnooga, Tennessee, USA
| | - Frédéric Poly
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Cheryl P. Ewing
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Yuening Jiao
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Ginyoung Lee
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Zuchao Ma
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Mario A. Monteiro
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Christina L. Hill
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Jason S. Ferderber
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Chad K. Porter
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - M. Stephen Trent
- Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas, USA
| | - Patricia Guerry
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
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Barjesteh N, Hodgins DC, St Paul M, Quinteiro-Filho WM, DePass C, Monteiro MA, Sharif S. Induction of chicken cytokine responses in vivo and in vitro by lipooligosaccharide of Campylobacter jejuni HS:10. Vet Microbiol 2013; 164:122-30. [PMID: 23473646 DOI: 10.1016/j.vetmic.2013.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/30/2013] [Accepted: 02/07/2013] [Indexed: 12/12/2022]
Abstract
Campylobacter jejuni is a pathogen of the gastrointestinal tract of humans, but colonizes chickens for prolonged periods without causing disease. It is unclear what host and bacterial mechanisms maintain a non-inflammatory state in chickens. The present work was undertaken to characterize cytokine responses of chickens to purified lipooligosaccharide (LOS) of C. jejuni HS:10. Chickens were injected with purified LOS, and expression of interleukin (IL)-1β (pro-inflammatory cytokine), IL-8 (pro-inflammatory chemokine), interferon (IFN)γ (Th1-like cytokine), IL-10 (immune regulatory/anti-inflammatory cytokine) and IL-13 (Th2-like cytokine) was evaluated in spleen using quantitative RT-PCR, up to 24h post-injection. In an in vitro study, splenocytes were incubated with LOS, and cytokine expression followed up to 18 h. Chickens injected with LOS had increased expression of IL-1β up to 24h later. Expression of IL-8 was significantly increased at 2h but then declined below baseline. Expression of IFNγ and IL-10 was increased significantly at 2h, but declined thereafter. Splenocytes incubated with LOS had increased expression of IL-1β and IL-8 up to 18 h of incubation. Expression of IFNγ was increased at 6 and 18 h, IL-10 was increased at 2h, but expression of IL-13 did not differ significantly up to 18h. It is concluded that LOS of C. jejuni can induce expression of pro-inflammatory IL-1β and IL-8, as well as IFNγ and IL-10 in chickens. More extensive studies with more prolonged exposure to LOS are needed to further clarify the interaction between C. jejuni and the chicken host.
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Affiliation(s)
- Neda Barjesteh
- Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada
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Abstract
Campylobacter jejuni is a major cause of food-borne gastroenteritis worldwide. While mortality is low, morbidity imparted by post-infectious sequelae such as Guillain-Barré syndrome, Reiter syndrome/reactive arthritis and irritable bowel syndrome is significant. In addition, the economic cost is high due to lost productivity. Food animals, particularly poultry, are the main reservoirs of C. jejuni. The over-use of antibiotics in the human population and in animal husbandry has led to an increase in antibiotic-resistant infections, particularly with fluoroquinolones. This is problematic because C. jejuni gastroenteritis is clinically indistinguishable from that caused by other bacterial pathogens, and such illnesses are usually treated empirically with fluoroquinolones. Since C. jejuni is naturally transformable, acquisition of additional genes imparting antibiotic resistance is likely. Therefore, an understanding of the antibiotic resistance mechanisms in C. jejuni is needed to provide proper therapy both to the veterinary and human populations.
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Affiliation(s)
- Nicole M Iovine
- University of Florida and the Malcom Randall VA Medical Center, Gainesville, FL, USA.
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Gnanadhas DP, Marathe SA, Chakravortty D. Biocides--resistance, cross-resistance mechanisms and assessment. Expert Opin Investig Drugs 2012; 22:191-206. [PMID: 23215733 DOI: 10.1517/13543784.2013.748035] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Antibiotic resistance in bacterial pathogens has increased worldwide leading to treatment failures. Concerns have been raised about the use of biocides as a contributing factor to the risk of antimicrobial resistance (AMR) development. In vitro studies demonstrating increase in resistance have often been cited as evidence for increased risks. It is therefore important to understand the mechanisms of resistance employed by bacteria toward biocides used in consumer products and their potential to impart cross-resistance to therapeutic antibiotics. AREAS COVERED In this review, the mechanisms of resistance and cross-resistance reported in the literature toward biocides commonly used in consumer products are summarized. The physiological and molecular techniques used in describing and examining these mechanisms are reviewed and application of these techniques for systematic assessment of biocides for their potential to develop resistance and/or cross-resistance is discussed. EXPERT OPINION The guidelines in the usage of biocides in household or industrial purpose should be monitored and regulated to avoid the emergence of any MDR strains. The genetic and molecular methods to monitor the resistance development to biocides should be developed and included in preclinical and clinical studies.
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Affiliation(s)
- Divya Prakash Gnanadhas
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research and Biosafety Laboratories, Indian Institute of Science, Bangalore 560012, India
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EptC of Campylobacter jejuni mediates phenotypes involved in host interactions and virulence. Infect Immun 2012. [PMID: 23184526 DOI: 10.1128/iai.01046-12] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Campylobacter jejuni is a natural commensal of the avian intestinal tract. However, the bacterium is also the leading cause of acute bacterial diarrhea worldwide and is implicated in development of Guillain-Barré syndrome. Like many bacterial pathogens, C. jejuni assembles complex surface structures that interface with the surrounding environment and are involved in pathogenesis. Recent work in C. jejuni identified a gene encoding a novel phosphoethanolamine (pEtN) transferase, EptC (Cj0256), that plays a promiscuous role in modifying the flagellar rod protein, FlgG; the lipid A domain of lipooligosaccharide (LOS); and several N-linked glycans. In this work, we report that EptC catalyzes the addition of pEtN to the first heptose sugar of the inner core oligosaccharide of LOS, a fourth enzymatic target. We also examine the role pEtN modification plays in circumventing detection and/or killing by host defenses. Specifically, we show that modification of C. jejuni lipid A with pEtN results in increased recognition by the human Toll-like receptor 4-myeloid differentiation factor 2 (hTLR4-MD2) complex, along with providing resistance to relevant mammalian and avian antimicrobial peptides (i.e., defensins). We also confirm the inability of aberrant forms of LOS to activate Toll-like receptor 2 (TLR2). Most exciting, we demonstrate that strains lacking eptC show decreased commensal colonization of chick ceca and reduced colonization of BALB/cByJ mice compared to wild-type strains. Our results indicate that modification of surface structures with pEtN by EptC is key to its ability to promote commensalism in an avian host and to survive in the mammalian gastrointestinal environment.
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Otto B, Haag LM, Fischer A, Plickert R, Kühl AA, Göbel UB, Heimesaat MM, Bereswill S. Campylobacter jejuni induces extra-intestinal immune responses via Toll-like-receptor-4 signaling in conventional IL-10 deficient mice with chronic colitis. Eur J Microbiol Immunol (Bp) 2012; 2:210-9. [PMID: 24688768 PMCID: PMC3962757 DOI: 10.1556/eujmi.2.2012.3.7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 06/27/2012] [Indexed: 11/19/2022] Open
Abstract
Campylobacter jejuni is one of the predominant causes for foodborne bacterial infections worldwide. We investigated whether signaling of C. jejuni-lipoproteins and -lipooligosaccharide via Toll-like-receptor (TLR) -2 and -4, respectively, is inducing intestinal and extra-intestinal immune responses following infection of conventional IL-10(-/-) mice with chronic colitis. At day 3 following oral infection, IL-10(-/-) mice lacking TLR-2 or TLR-4 harbored comparable C. jejuni strain ATCC 43431 loads in their colon. Interestingly, infected TLR-4(-/-) IL-10(-/-) mice displayed less compromized epithelial barrier function as indicated by lower translocation rates of live gut commensals into mesenteric lymphnodes (MLNs), and exhibited less distinct B lymphocyte responses in their colonic mucosa as compared to naїve IL-10(-/-) controls. Furthermore, in extra-intestinal compartments such as MLNs and spleens, abundance of myeloid cells was less distinct whereas relative percentages of activated T helper cells and cytotoxic T cells were higher in spleens and dendritic cells more abundant in MLNs of infected IL-10(-/-) animals lacking TLR-4 as compared to IL-10(-/-) controls. Taken together, in conventionally colonized IL-10(-/-) mice, TLR-4, but not TLR-2, is involved in mediating extra-intestinal pro-inflammatory immune responses following C. jejuni infection. Thus, conventional IL-10(-/-) mice are well suited to further dissect mechanisms underlying Campylobacter infections in vivo.
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Affiliation(s)
- B. Otto
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
| | - L.-M. Haag
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
| | - A. Fischer
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
| | - R. Plickert
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
| | - A. A. Kühl
- Department of Internal Medicine, Rheumatology and Clinical
Immunology / Research Center Immuno-Sciences (RCIS), Charité – University
Medicine BerlinBerlinGermany
| | - U. B. Göbel
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
| | - M. M. Heimesaat
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
| | - S. Bereswill
- Department of Microbiology and Hygiene, Charité – University
Medicine BerlinBerlinGermany
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Campylobacter jejuni induces acute enterocolitis in gnotobiotic IL-10-/- mice via Toll-like-receptor-2 and -4 signaling. PLoS One 2012; 7:e40761. [PMID: 22808254 PMCID: PMC3393706 DOI: 10.1371/journal.pone.0040761] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/12/2012] [Indexed: 12/31/2022] Open
Abstract
Background Campylobacter jejuni is a leading cause of foodborne bacterial enterocolitis worldwide. Investigation of immunopathology is hampered by a lack of suitable vertebrate models. We have recently shown that gnotobiotic mice as well as conventional IL-10−/− animals are susceptible to C. jejuni infection and develop intestinal immune responses. However, clinical symptoms of C. jejuni infection were rather subtle and did not reflect acute bloody diarrhea seen in human campylobacteriosis. Methodology/Principal Findings In order to overcome these limitations we generated gnotobiotic IL-10−/− mice by quintuple antibiotic treatment starting right after weaning. The early treatment was essential to prevent these animals from chronic colitis. Following oral infection C. jejuni colonized the gastrointestinal tract at high levels and induced acute enterocolitis within 7 days as indicated by bloody diarrhea and pronounced histopathological changes of the colonic mucosa. Immunopathology was further characterized by increased numbers of apoptotic cells, regulatory T-cells, T- and B-lymphocytes as well as elevated TNF-α, IFN-γ, and MCP-1 concentrations in the inflamed colon. The induction of enterocolitis was specific for C. jejuni given that control animals infected with a commensal E. coli strain did not display any signs of disease. Most strikingly, intestinal immunopathology was ameliorated in mice lacking Toll-like-receptors-2 or -4 indicating that C. jejuni lipoproteins and lipooligosaccharide are essential for induction and progression of immunopathology. Conclusion/Significance Gnotobiotic IL-10−/− mice develop acute enterocolitis following C. jejuni infection mimicking severe episodes of human campylobacteriosis and are thus well suited to further dissect mechanisms underlying Campylobacter infections in vivo.
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van Dijk A, Herrebout M, Tersteeg-Zijderveld MHG, Tjeerdsma-van Bokhoven JLM, Bleumink-Pluym N, Jansman AJM, Veldhuizen EJA, Haagsman HP. Campylobacter jejuni is highly susceptible to killing by chicken host defense peptide cathelicidin-2 and suppresses intestinal cathelicidin-2 expression in young broilers. Vet Microbiol 2012; 160:347-54. [PMID: 22728124 DOI: 10.1016/j.vetmic.2012.05.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 01/19/2023]
Abstract
Little is known about the interactions of chicken host defense peptides (HDPs) with Campylobacter jejuni in young chicks. To examine the role of the chicken HDP, cathelicidin-2 (CATH-2) in host-pathogen interactions we challenged 4-day-old Ross 308 broilers with a chicken-derived C. jejuni isolate (WS356) and used the chicken pathogen Salmonella enterica Enteritidis phage type 4 (FGT1) as a reference. Immunohistochemical staining was used to localize CATH-2, C. jejuni and Salmonella enteritidis. Intestinal CATH-2 mRNA expression levels were determined by quantitative PCR. Antibacterial activities of CATH-2 peptide against C. jejuni and S. enteritidis isolates were assessed in colony count assays. In contrast to S. enteritidis, C. jejuni was not seen to attach to intestinal epithelium and C. jejuni challenge did not result in recruitment of CATH-2 containing heterophils to the small intestinal lamina propria. Minimal inhibitory concentrations found for CATH-2 peptide against human- and chicken-derived C. jejuni isolates were similar (0.6-2.5 μM) and much lower than for S. enteritidis (20 μM). Compared to wild-type C. jejuni 81116, the lipooligosaccharide (LOS)-deficient 81116ΔwaaF mutant was much more susceptible to CATH-2. Interestingly, CATH-2 mRNA expression levels in the small intestine were significantly lower 48 h p.i. in C. jejuni-challenged chicks. These findings indicate that human clinical and chicken-derived C. jejuni are equally highly susceptible to chicken CATH-2 peptide and that C. jejuni uses LOS to protect itself to some extent against HDPs. Moreover, suppression of intestinal CATH-2 expression levels may be part of the C. jejuni immune evasion strategy.
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Affiliation(s)
- Albert van Dijk
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.165, 3508 TD Utrecht, The Netherlands
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Frirdich E, Biboy J, Adams C, Lee J, Ellermeier J, Gielda LD, DiRita VJ, Girardin SE, Vollmer W, Gaynor EC. Peptidoglycan-modifying enzyme Pgp1 is required for helical cell shape and pathogenicity traits in Campylobacter jejuni. PLoS Pathog 2012; 8:e1002602. [PMID: 22457624 PMCID: PMC3310789 DOI: 10.1371/journal.ppat.1002602] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 02/08/2012] [Indexed: 11/18/2022] Open
Abstract
The impact of bacterial morphology on virulence and transmission attributes of pathogens is poorly understood. The prevalent enteric pathogen Campylobacter jejuni displays a helical shape postulated as important for colonization and host interactions. However, this had not previously been demonstrated experimentally. C. jejuni is thus a good organism for exploring the role of factors modulating helical morphology on pathogenesis. We identified an uncharacterized gene, designated pgp1 (peptidoglycan peptidase 1), in a calcofluor white-based screen to explore cell envelope properties important for C. jejuni virulence and stress survival. Bioinformatics showed that Pgp1 is conserved primarily in curved and helical bacteria. Deletion of pgp1 resulted in a striking, rod-shaped morphology, making pgp1 the first C. jejuni gene shown to be involved in maintenance of C. jejuni cell shape. Pgp1 contributes to key pathogenic and cell envelope phenotypes. In comparison to wild type, the rod-shaped pgp1 mutant was deficient in chick colonization by over three orders of magnitude and elicited enhanced secretion of the chemokine IL-8 in epithelial cell infections. Both the pgp1 mutant and a pgp1 overexpressing strain – which similarly produced straight or kinked cells – exhibited biofilm and motility defects. Detailed peptidoglycan analyses via HPLC and mass spectrometry, as well as Pgp1 enzyme assays, confirmed Pgp1 as a novel peptidoglycan DL-carboxypeptidase cleaving monomeric tripeptides to dipeptides. Peptidoglycan from the pgp1 mutant activated the host cell receptor Nod1 to a greater extent than did that of wild type. This work provides the first link between a C. jejuni gene and morphology, peptidoglycan biosynthesis, and key host- and transmission-related characteristics. Bacterial cell shape is dictated by the composition of the cell envelope component peptidoglycan. Some important pathogens have a characteristic helical corkscrew morphology that may help them burrow into mucus overlaying cells to initiate colonization and pathogenicity. One example is Campylobacter jejuni, the leading cause of bacterial-induced diarrheal disease in the developed world. Direct evidence supporting the hypothesis that C. jejuni shape is related to its pathogenicity traits has not previously been provided. We identified a gene encoding a peptidase modifying peptidoglycan that is essential for maintaining the C. jejuni corkscrew shape. We can now connect a C. jejuni gene with morphology and peptidoglycan biosynthesis. Loss of this gene was also found to affect pathogenic attributes such as chicken colonization, biofilms, motility, and activation of host inflammatory mediators. In addition, this is the first study to thoroughly characterize C. jejuni peptidoglycan structure and to identify a gene involved in peptidoglycan maintenance. Our findings highlight an emerging theme in bacterial pathogenesis research: the connection between bacterial cell biology and pathogenesis. Finally, our characterization of C. jejuni cell shape and peptidoglycan provides a starting point for further work in this area in C. jejuni and other bacteria with curved and helical morphologies.
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Affiliation(s)
- Emilisa Frirdich
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jacob Biboy
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Calvin Adams
- Wine Research Centre, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jooeun Lee
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jeremy Ellermeier
- Department of Microbiology and Immunology & Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Lindsay Davis Gielda
- Department of Microbiology and Immunology & Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Victor J. DiRita
- Department of Microbiology and Immunology & Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Stephen E. Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Erin C. Gaynor
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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Szymanski CM, Gaynor E. How a sugary bug gets through the day: recent developments in understanding fundamental processes impacting Campylobacter jejuni pathogenesis. Gut Microbes 2012; 3:135-44. [PMID: 22555465 PMCID: PMC3370946 DOI: 10.4161/gmic.19488] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Campylobacter jejuni is a highly prevalent yet fastidious bacterial pathogen that poses a significant health burden worldwide. Lacking many hallmark virulence factors, it is becoming increasingly clear that C. jejuni pathogenesis involves different strategies compared with other well-characterized enteric organisms. This includes the involvement of basic biological processes and cell envelope glycans in a number of aspects related to pathogenesis. The past few years have seen significant progress in the understanding of these pathways and how they relate to C. jejuni fundamental biology, stress survival, colonization, and virulence attributes. This review focuses on recent studies in three general areas where "pathogenesis" and "basic biology" overlap: physiology, stress responses and glycobiology.
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Affiliation(s)
- Christine M. Szymanski
- Alberta Glycomics Centre and Department of Biological Sciences; University of Alberta; Edmonton, Canada,Correspondence to: Christine M. Szymanski, or Erin Gaynor,
| | - Erin Gaynor
- Department of Microbiology and Immunology; University of British Columbia; Vancouver, Canada,Correspondence to: Christine M. Szymanski, or Erin Gaynor,
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van Dijk A, Molhoek E, Bikker F, Yu PL, Veldhuizen E, Haagsman H. Avian cathelicidins: Paradigms for the development of anti-infectives. Vet Microbiol 2011; 153:27-36. [DOI: 10.1016/j.vetmic.2011.03.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/18/2011] [Accepted: 03/23/2011] [Indexed: 11/28/2022]
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The Campylobacter jejuni NCTC11168 capsule prevents excessive cytokine production by dendritic cells. Med Microbiol Immunol 2011; 201:137-44. [PMID: 21863342 DOI: 10.1007/s00430-011-0214-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Indexed: 02/06/2023]
Abstract
Campylobacter jejuni is the leading cause of human bacterial gastroenteritis worldwide, mainly caused by handling and consumption of contaminated poultry. However, the immune response to infection is poorly understood. Here, the impact of the C. jejuni capsule, flagella and the N-linked glycosylation system on cytokine production by dendritic cells was investigated. Bone marrow-derived murine dendritic cells (BMDCs) infected with C. jejuni lacking the N-linked glycosylation system produced similar amounts of cytokines compared to cells infected with C. jejuni 11168H wild-type (WT) cultures. C. jejuni flagellin FlaA mutants elicited reduced IL-6 and IL-10 production in BMDCs compared to C. jejuni WT and this reduction was more pronounced in TLR4(-/-) BMDCs. An acapsular C. jejuni mutant as well as a mutant lacking the O-methyl phosphoramidate modification of the capsule elicited a higher cytokine response in BMDCs. Experiments with TLR4(-/-) BMDCs revealed that this increased cytokine production was not solely dependent on signalling through TLR4. Therefore, the C. jejuni capsule is important to prevent excessive cytokine production by BMDCs and even minor changes in capsule composition such as the lack of the O-methyl phosphoramidate modification can lead to increased cytokine production.
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Novel murine infection models provide deep insights into the "ménage à trois" of Campylobacter jejuni, microbiota and host innate immunity. PLoS One 2011; 6:e20953. [PMID: 21698299 PMCID: PMC3115961 DOI: 10.1371/journal.pone.0020953] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 05/13/2011] [Indexed: 12/11/2022] Open
Abstract
Background Although Campylobacter jejuni-infections have a high prevalence worldwide and represent a significant socioeconomic burden, it is still not well understood how C. jejuni causes intestinal inflammation. Detailed investigation of C. jejuni-mediated intestinal immunopathology is hampered by the lack of appropriate vertebrate models. In particular, mice display colonization resistance against this pathogen. Methodology/Principal Findings To overcome these limitations we developed a novel C. jejuni-infection model using gnotobiotic mice in which the intestinal flora was eradicated by antibiotic treatment. These animals could then be permanently associated with a complete human (hfa) or murine (mfa) microbiota. After peroral infection C. jejuni colonized the gastrointestinal tract of gnotobiotic and hfa mice for six weeks, whereas mfa mice cleared the pathogen within two days. Strikingly, stable C. jejuni colonization was accompanied by a pro-inflammatory immune response indicated by increased numbers of T- and B-lymphocytes, regulatory T-cells, neutrophils and apoptotic cells, as well as increased concentrations of TNF-α, IL-6, and MCP-1 in the colon mucosa of hfa mice. Analysis of MyD88−/−, TRIF−/−, TLR4−/−, and TLR9−/− mice revealed that TLR4- and TLR9-signaling was essential for immunopathology following C. jejuni-infection. Interestingly, C. jejuni-mutant strains deficient in formic acid metabolism and perception induced less intestinal immunopathology compared to the parental strain infection. In summary, the murine gut flora is essential for colonization resistance against C. jejuni and can be overcome by reconstitution of gnotobiotic mice with human flora. Detection of C. jejuni-LPS and -CpG-DNA by host TLR4 and TLR9, respectively, plays a key role in immunopathology. Finally, the host immune response is tightly coupled to bacterial formic acid metabolism and invasion fitness. Conclusion/Significance We conclude that gnotobiotic and “humanized” mice represent excellent novel C. jejuni-infection and -inflammation models and provide deep insights into the immunological and molecular interplays between C. jejuni, microbiota and innate immunity in human campylobacteriosis.
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Moran AP. Altered linkage of hydroxyacyl chains in bacterial lipid A. J Biol Chem 2010; 285:le11; author reply le12. [PMID: 20601432 DOI: 10.1074/jbc.l110.102061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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van Mourik A, Steeghs L, van Laar J, Meiring HD, Hamstra HJ, van Putten JP, Wösten MM. Reply to Moran: Modification of Campylobacter jejuni Lipid A. J Biol Chem 2010. [DOI: 10.1074/jbc.n110.102061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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