101
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Korneev KV, Kondakova AN, Sviriaeva EN, Mitkin NA, Palmigiano A, Kruglov AA, Telegin GB, Drutskaya MS, Sturiale L, Garozzo D, Nedospasov SA, Knirel YA, Kuprash DV. Hypoacylated LPS from Foodborne Pathogen Campylobacter jejuni Induces Moderate TLR4-Mediated Inflammatory Response in Murine Macrophages. Front Cell Infect Microbiol 2018; 8:58. [PMID: 29535976 PMCID: PMC5835049 DOI: 10.3389/fcimb.2018.00058] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/12/2018] [Indexed: 11/13/2022] Open
Abstract
Toll-like receptor 4 (TLR4) initiates immune response against Gram-negative bacteria upon specific recognition of lipid A moiety of lipopolysaccharide (LPS), the major component of their cell wall. Some natural differences between LPS variants in their ability to interact with TLR4 may lead to either insufficient activation that may not prevent bacterial growth, or excessive activation which may lead to septic shock. In this study we evaluated the biological activity of LPS isolated from pathogenic strain of Campylobacter jejuni, the most widespread bacterial cause of foodborne diarrhea in humans. With the help of hydrophobic chromatography and MALDI-TOF mass spectrometry we showed that LPS from a C. jejuni strain O2A consists of both hexaacyl and tetraacyl forms. Since such hypoacylation can result in a reduced immune response in humans, we assessed the activity of LPS from C. jejuni in mouse macrophages by measuring its capacity to activate TLR4-mediated proinflammatory cytokine and chemokine production, as well as NFκB-dependent reporter gene transcription. Our data support the hypothesis that LPS acylation correlates with its bioactivity.
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Affiliation(s)
- Kirill V. Korneev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Immunology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Anna N. Kondakova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina N. Sviriaeva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Immunology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Nikita A. Mitkin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Angelo Palmigiano
- CNR Institute for Polymers Composites and Biomaterials, Catania, Italy
| | - Andrey A. Kruglov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- German Rheumatism Research Center, Leibniz Institute, Berlin, Germany
| | - Georgy B. Telegin
- Branch of Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, Russia
| | - Marina S. Drutskaya
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Luisa Sturiale
- CNR Institute for Polymers Composites and Biomaterials, Catania, Italy
| | - Domenico Garozzo
- CNR Institute for Polymers Composites and Biomaterials, Catania, Italy
| | - Sergei A. Nedospasov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Immunology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- German Rheumatism Research Center, Leibniz Institute, Berlin, Germany
| | - Yuriy A. Knirel
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Dmitry V. Kuprash
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Immunology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
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102
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Sengyee S, Yoon SH, Paksanont S, Yimthin T, Wuthiekanun V, Limmathurotsakul D, West TE, Ernst RK, Chantratita N. Comprehensive analysis of clinical Burkholderia pseudomallei isolates demonstrates conservation of unique lipid A structure and TLR4-dependent innate immune activation. PLoS Negl Trop Dis 2018; 12:e0006287. [PMID: 29474381 PMCID: PMC5842036 DOI: 10.1371/journal.pntd.0006287] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 03/07/2018] [Accepted: 01/31/2018] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei is an environmental bacterium that causes melioidosis, a major community-acquired infection in tropical regions. Melioidosis presents with a range of clinical symptoms, is often characterized by a robust inflammatory response, may relapse after treatment, and results in high mortality rates. Lipopolysaccharide (LPS) of B. pseudomallei is a potent immunostimulatory molecule comprised of lipid A, core, and O-polysaccharide (OPS) components. Four B. pseudomallei LPS types have been described based on SDS-PAGE patterns that represent the difference of OPS-type A, type B, type B2 and rough LPS. The majority of B. pseudomallei isolates are type A. We used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) followed by electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QqTOF MS) and gas chromatography to characterize the lipid A of B. pseudomallei within LPS type A isolates. We determined that B. pseudomallei lipid A is represented by penta- and tetra-acylated species modified with 4-amino-4-deoxy-arabinose (Ara4N). The MALDI-TOF profiles from 171 clinical B. pseudomallei isolates, including 68 paired primary and relapse isolates and 35 within-host isolates were similar. We did not observe lipid A structural changes when the bacteria were cultured in different growth conditions. Dose-dependent NF-κB activation in HEK cells expressing TLR4 was observed using multiple heat-killed B. pseudomallei isolates and corresponding purified LPS. We demonstrated that TLR4-dependent NF-κB activation induced by heat-killed bacteria or LPS prepared from OPS deficient mutant was significantly greater than those induced by wild type B. pseudomallei. These findings suggest that the structure of B. pseudomallei lipid A is highly conserved in a wide variety of clinical and environmental circumstances but that the presence of OPS may modulate LPS-driven innate immune responses in melioidosis.
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Affiliation(s)
- Sineenart Sengyee
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sung Hwan Yoon
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States of America
| | - Suporn Paksanont
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thatcha Yimthin
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - T. Eoin West
- Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, WA, United States of America
- International Respiratory and Severe Illness Center, University of Washington, Seattle, WA, United States of America
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States of America
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- * E-mail:
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103
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Yang Q, Li M, Spiller OB, Andrey DO, Hinchliffe P, Li H, MacLean C, Niumsup P, Powell L, Pritchard M, Papkou A, Shen Y, Portal E, Sands K, Spencer J, Tansawai U, Thomas D, Wang S, Wang Y, Shen J, Walsh T. Balancing mcr-1 expression and bacterial survival is a delicate equilibrium between essential cellular defence mechanisms. Nat Commun 2017; 8:2054. [PMID: 29233990 PMCID: PMC5727292 DOI: 10.1038/s41467-017-02149-0] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 11/09/2017] [Indexed: 12/20/2022] Open
Abstract
MCR-1 is a lipid A modifying enzyme that confers resistance to the antibiotic colistin. Here, we analyse the impact of MCR-1 expression on E. coli morphology, fitness, competitiveness, immune stimulation and virulence. Increased expression of mcr-1 results in decreased growth rate, cell viability, competitive ability and significant degradation in cell membrane and cytoplasmic structures, compared to expression of catalytically inactive MCR-1 (E246A) or MCR-1 soluble component. Lipopolysaccharide (LPS) extracted from mcr-1 strains induces lower production of IL-6 and TNF, when compared to control LPS. Compared to their parent strains, high-level colistin resistance mutants (HLCRMs) show reduced fitness (relative fitness is 0.41-0.78) and highly attenuated virulence in a Galleria mellonella infection model. Furthermore, HLCRMs are more susceptible to most antibiotics than their respective parent strains. Our results show that the bacterium is challenged to find a delicate equilibrium between expression of MCR-1-mediated colistin resistance and minimalizing toxicity and thus ensuring cell survival.
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Affiliation(s)
- Qiue Yang
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Mei Li
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - Owen B Spiller
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - Diego O Andrey
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK
- Service of Infectious Diseases, Geneva University Hospitals and Faculty of Medicine, 1211, Geneva, Switzerland
| | - Philip Hinchliffe
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK
| | - Hui Li
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing, 100013, China
| | - Craig MacLean
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Pannika Niumsup
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Lydia Powell
- Advanced Therapies Group, Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Manon Pritchard
- Advanced Therapies Group, Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Andrei Papkou
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Yingbo Shen
- Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Edward Portal
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - Kirsty Sands
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK
| | - Uttapoln Tansawai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - David Thomas
- Advanced Therapies Group, Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Shaolin Wang
- Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Yang Wang
- Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Jianzhong Shen
- Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Timothy Walsh
- Department of Medical Microbiology and Infectious Disease, Division of Infection and Immunity, Cardiff University, Cardiff, CF14 4XN, UK.
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104
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Sheu JR, Chen ZC, Hsu MJ, Wang SH, Jung KW, Wu WF, Pan SH, Teng RD, Yang CH, Hsieh CY. CME-1, a novel polysaccharide, suppresses iNOS expression in lipopolysaccharide-stimulated macrophages through ceramide-initiated protein phosphatase 2A activation. J Cell Mol Med 2017; 22:999-1013. [PMID: 29214724 PMCID: PMC5783865 DOI: 10.1111/jcmm.13424] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/20/2017] [Indexed: 12/22/2022] Open
Abstract
CME-1, a novel water-soluble polysaccharide purified from Ophiocordyceps sinensis mycelia, has anti-oxidative, antithrombotic and antitumour properties. In this study, other major attributes of CME-1, namely anti-inflammatory and immunomodulatory properties, were investigated. Treating lipopolysaccharide (LPS)-stimulated RAW 264.7 cells with CME-1 concentration-dependently suppressed nitric oxide formation and inducible nitric oxide synthase (iNOS) expression. In the CME-1-treated RAW 264.7 cells, LPS-induced IκBα degradation and the phosphorylation of p65, Akt and mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase, c-Jun N-terminal kinase and p38, were reduced. Treatment with a protein phosphatase 2A (PP2A)-specific inhibitor, significantly reversed the CME-1-suppressed iNOS expression; IκBα degradation; and p65, Akt and MAPK phosphorylation. PP2A activity up-regulation and PP2A demethylation reduction were also observed in the cells. Moreover, CME-1-induced PP2A activation and its subsequent suppression of LPS-activated RAW 264.7 cells were diminished by the inhibition of ceramide signals. LPS-induced reactive oxygen species (ROS) and hydroxyl radical formation were eliminated by treating RAW 264.7 cells with CME-1. Furthermore, the role of ceramide signalling pathway and anti-oxidative property were also demonstrated in CME-1-mediated inhibition of LPS-activated primary peritoneal macrophages. In conclusion, CME-1 suppressed iNOS expression by up-regulating ceramide-induced PP2A activation and reducing ROS production in LPS-stimulated macrophages. CME-1 is a potential therapeutic agent for treating inflammatory diseases.
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Affiliation(s)
- Joen-Rong Sheu
- Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Zhih-Cherng Chen
- Graduate Institute of Medical Sciences, School of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Cardiology, Chi-Mei Medical Center, Tainan City, Taiwan.,Department of Pharmacy, Chia Nan University of Pharmacy & Science, Tainan City, Taiwan
| | - Ming-Jen Hsu
- Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shwu-Huey Wang
- Core Facility Center, Office of Research and Development, Taipei Medical University, Taipei, Taiwan
| | - Kuo-Wei Jung
- Graduate Institute of Medical Sciences, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wei-Fan Wu
- Graduate Institute of Medical Sciences, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Szu-Han Pan
- Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ruei-Dun Teng
- Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Hao Yang
- Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Cheng-Ying Hsieh
- Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan
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105
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Leker K, Lozano-Pope I, Bandyopadhyay K, Choudhury BP, Obonyo M. Comparison of lipopolysaccharides composition of two different strains of Helicobacter pylori. BMC Microbiol 2017; 17:226. [PMID: 29202699 PMCID: PMC5715995 DOI: 10.1186/s12866-017-1135-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/23/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Helicobacter pylori (H. pylori) is a Gram-negative, microaerophilic bacterium that is recognized as a major cause of chronic gastritis, peptic ulcers, and gastric cancer. Comparable to other Gram-negative bacteria, lipopolysaccharides (LPS) are an important cellular component of the outer membrane of H. pylori. The LPS of this organism plays a key role in its colonization and persistence in the stomach. In addition, H. pylori LPS modulates pathogen-induced host inflammatory responses resulting in chronic inflammation within the gastrointestinal tract. Very little is known about the comparative LPS compositions of different strains of H. pylori with varied degree of virulence in human. Therefore, LPS was analyzed from two strains of H. pylori with differing potency in inducing inflammatory responses (SS1 and G27). LPS were extracted from aqueous and phenol layer of hot-phenol water extraction method and subjected for composition analysis by gas chromatography - mass spectrometry (GC-MS) to sugar and fatty acid compositions. RESULTS The major difference between the two strains of H. pylori is the presence of Rhamnose, Fucose and GalNAc in the SS1 strain, which was either not found or with low abundance in the G27 strain. On the other hand, high amount of Mannose was present in G27 in comparison to SS1. Fatty acid composition of lipid-A portion also showed considerable amount of differences between the two strains, phenol layer of SS1 had enhanced amount of 3 hydroxy decanoic acid (3-OH-C10:0) and 3-hydroxy dodecanoic acid (3-OH-C12:0) which were not present in G27, whereas myristic acid (C14:0) was present in G27 in relatively high amount. CONCLUSION The composition analysis of H. pylori LPS, revealed differences in sugars and fatty acids composition between a mouse adapted strain SS1 and G27. This knowledge provides a novel way to dissect out their importance in host-pathogen interaction in further studies.
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Affiliation(s)
- Kristy Leker
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, California 92093 USA
| | - Ivonne Lozano-Pope
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, California 92093 USA
| | - Keya Bandyopadhyay
- Glycotechnology Core Resources, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, California 92093 USA
| | - Biswa P. Choudhury
- Glycotechnology Core Resources, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, California 92093 USA
| | - Marygorret Obonyo
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, California 92093 USA
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106
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Mass spectrometry analysis of intact Francisella bacteria identifies lipid A structure remodeling in response to acidic pH stress. Biochimie 2017; 141:16-20. [DOI: 10.1016/j.biochi.2017.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/09/2017] [Indexed: 11/18/2022]
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107
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Pawlak A, Rybka J, Dudek B, Krzyżewska E, Rybka W, Kędziora A, Klausa E, Bugla-Płoskońska G. Salmonella O48 Serum Resistance is Connected with the Elongation of the Lipopolysaccharide O-Antigen Containing Sialic Acid. Int J Mol Sci 2017; 18:E2022. [PMID: 28934165 PMCID: PMC5666704 DOI: 10.3390/ijms18102022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/09/2017] [Accepted: 09/12/2017] [Indexed: 12/27/2022] Open
Abstract
Complement is one of the most important parts of the innate immune system. Some bacteria can gain resistance against the bactericidal action of complement by decorating their outer cell surface with lipopolysaccharides (LPSs) containing a very long O-antigen or with specific outer membrane proteins. Additionally, the presence of sialic acid in the LPS molecules can provide a level of protection for bacteria, likening them to human cells, a phenomenon known as molecular mimicry. Salmonella O48, which contains sialic acid in the O-antigen, is the major cause of reptile-associated salmonellosis, a worldwide public health problem. In this study, we tested the effect of prolonged exposure to human serum on strains from Salmonella serogroup O48, specifically on the O-antigen length. After multiple passages in serum, three out of four tested strains became resistant to serum action. The gas-liquid chromatography/tandem mass spectrometry analysis showed that, for most of the strains, the average length of the LPS O-antigen increased. Thus, we have discovered a link between the resistance of bacterial cells to serum and the elongation of the LPS O-antigen.
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Affiliation(s)
- Aleksandra Pawlak
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
| | - Jacek Rybka
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
| | - Bartłomiej Dudek
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
| | - Eva Krzyżewska
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
| | - Wojciech Rybka
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
| | - Anna Kędziora
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
| | - Elżbieta Klausa
- Regional Centre of Transfusion Medicine and Blood Bank, 50-345 Wrocław, Poland.
| | - Gabriela Bugla-Płoskońska
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
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108
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Volgers C, Savelkoul PHM, Stassen FRM. Gram-negative bacterial membrane vesicle release in response to the host-environment: different threats, same trick? Crit Rev Microbiol 2017; 44:258-273. [PMID: 28741415 DOI: 10.1080/1040841x.2017.1353949] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Bacteria are confronted with a multitude of stressors when occupying niches within the host. These stressors originate from host defense mechanisms, other bacteria during niche competition or result from physiological challenges such as nutrient limitation. To counteract these stressors, bacteria have developed a stress-induced network to mount the adaptations required for survival. These stress-induced adaptations include the release of membrane vesicles from the bacterial envelope. Membrane vesicles can provide bacteria with a plethora of immediate and ultimate benefits for coping with environmental stressors. This review addresses how membrane vesicles aid Gram-negative bacteria to cope with host-associated stress factors, focusing on vesicle biogenesis and the physiological functions. As many of the pathways, that drive vesicle biogenesis, confer we propose that shedding of membrane vesicles by Gram-negative bacteria entails an integrated part of general stress responses.
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Affiliation(s)
- Charlotte Volgers
- a Department of Medical Microbiology, School of Nutrition and Translational Research in Metabolism (NUTRIM) , Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Paul H M Savelkoul
- a Department of Medical Microbiology, School of Nutrition and Translational Research in Metabolism (NUTRIM) , Maastricht University Medical Centre , Maastricht , The Netherlands.,b Department of Medical Microbiology and Infection Control , VU University Medical Center , Amsterdam , The Netherlands
| | - Frank R M Stassen
- a Department of Medical Microbiology, School of Nutrition and Translational Research in Metabolism (NUTRIM) , Maastricht University Medical Centre , Maastricht , The Netherlands
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109
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Yang L, Liu S, Ding J, Dai R, He C, Xu K, Honaker CF, Zhang Y, Siegel P, Meng H. Gut Microbiota Co-microevolution with Selection for Host Humoral Immunity. Front Microbiol 2017; 8:1243. [PMID: 28725219 PMCID: PMC5495859 DOI: 10.3389/fmicb.2017.01243] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/20/2017] [Indexed: 12/24/2022] Open
Abstract
To explore coevolution between the gut microbiota and the humoral immune system of the host, we used chickens as the model organism. The host populations were two lines (HAS and LAS) developed from a common founder that had undergone 40 generations of divergent selection for antibody titers to sheep red blood cells (SRBC) and two relaxed sublines (HAR and LAR). Analysis revealed that microevolution of host humoral immunity contributed to the composition of gut microbiota at the taxa level. Relaxing selection enriched some microorganisms whose functions were opposite to host immunity. Particularly, Ruminococcaceae and Oscillospira enriched in high antibody relaxed (HAR) and contributed to reduction in antibody response, while Lactobacillus increased in low antibody relaxed (LAR) and elevated the antibody response. Microbial functional analysis showed that alterations were involved in pathways relating to the immune system and infectious diseases. Our findings demonstrated co-microevolution relationships of host-microbiota and that gut microorganisms influenced host immunity.
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Affiliation(s)
- Lingyu Yang
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
| | - Shuyun Liu
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
| | - Jinmei Ding
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
| | - Ronghua Dai
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
| | - Chuan He
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
| | - Ke Xu
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
| | - Christa F Honaker
- Department of Animal and Poultry Sciences, Virginia TechBlacksburg, VA, United States
| | - Yan Zhang
- Carilion ClinicRoanoke, VA, United States
| | - Paul Siegel
- Department of Animal and Poultry Sciences, Virginia TechBlacksburg, VA, United States
| | - He Meng
- Shanghai Key Laboratory of Veterinary Biotechnology, Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
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110
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Abstract
Adjuvant properties of bacterial cell wall components like MPLA (monophosphoryl lipid A) are well described and have gained FDA approval for use in vaccines such as Cervarix. MPLA is the product of chemically modified lipooligosaccharide (LOS), altered to diminish toxic proinflammatory effects while retaining adequate immunogenicity. Despite the virtually unlimited number of potential sources among bacterial strains, the number of useable compounds within this promising class of adjuvants are few. We have developed bacterial enzymatic combinatorial chemistry (BECC) as a method to generate rationally designed, functionally diverse lipid A. BECC removes endogenous or introduces exogenous lipid A-modifying enzymes to bacteria, effectively reprogramming the lipid A biosynthetic pathway. In this study, BECC is applied within an avirulent strain of Yersinia pestis to develop structurally distinct LOS molecules that elicit differential Toll-like receptor 4 (TLR4) activation. Using reporter cell lines that measure NF-κB activation, BECC-derived molecules were screened for the ability to induce a lower proinflammatory response than Escherichia coli LOS. Their structures exhibit varied, dose-dependent, TLR4-driven NF-κB activation with both human and mouse TLR4 complexes. Additional cytokine secretion screening identified molecules that induce levels of tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8) comparable to the levels induced by phosphorylated hexa-acyl disaccharide (PHAD). The lead candidates demonstrated potent immunostimulation in mouse splenocytes, human primary blood mononuclear cells (PBMCs), and human monocyte-derived dendritic cells (DCs). This newly described system allows directed programming of lipid A synthesis and has the potential to generate a diverse array of TLR4 agonist candidates.IMPORTANCE There is an urgent need to develop effective vaccines against infectious diseases that continue to be major causes of morbidity and mortality worldwide. Making effective vaccines requires selecting an adjuvant to strengthen an appropriate and protective immune response. This work describes a practical method, bacterial enzymatic combinatorial chemistry (BECC), for generating functionally diverse molecules for adjuvant use. These molecules were analyzed in cell culture for their ability to initiate immune stimulatory activity. Several of the assays described herein show promising in vitro cytokine production and costimulatory molecule expression results, suggesting that the BECC molecules may be useful in future vaccine preparations.
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Nemati M, Larussa T, Khorramdelazad H, Mahmoodi M, Jafarzadeh A. Toll-like receptor 2: An important immunomodulatory molecule during Helicobacter pylori infection. Life Sci 2017; 178:17-29. [PMID: 28427896 DOI: 10.1016/j.lfs.2017.04.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/06/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022]
Abstract
Toll like receptors (TLRs) are an essential subset of pathogen recognition receptors (PRRs) which identify the microbial components and contribute in the regulation of innate and adaptive immune responses against the infectious agents. The TLRs, especially TLR2, TLR4, TLR5 and TLR9, participate in the induction of immune response against H. pylori. TLR2 is expressed on a number of immune and non-immune cells and recognizes a vast broad of microbial components due to its potential to form heterodimers with other TLRs, including TLR1, TLR6 and TLR10. A number of H. pylori-related molecules may contribute to TLR2-dependent responses, including HP-LPS, HP-HSP60 and HP-NAP. TLR2 plays a pivotal role in regulation of immune response to H. pylori through activation of NF-κB and induction of cytokine expression in epithelial cells, monocytes/macrophages, dendritic cells, neutrophils and B cells. The TLR2-related immune response that is induced by H. pylori-derived components may play an important role regarding the outcome of the infection toward bacterial elimination, persistence or pathological reactions. The immunomodulatory and immunoregulatory roles of TLR2 during H. pylori infection were considered in this review. TLR2 could be considered as an interesting therapeutic target for treatment of H. pylori-related diseases.
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Affiliation(s)
- Maryam Nemati
- Department of Laboratory Sciences, School of Para-Medicine, Kerman University of Medical Sciences, Kerman, Iran; Department of Microbiology, School of Medicine, Islamic Azad University Branch of Kerman, Kerman, Iran
| | - Tiziana Larussa
- Department of Health Sciences, University of Catanzaro "Magna Graecia", 88100 Catanzaro, Italy
| | - Hossein Khorramdelazad
- Molecular Medicine Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Merat Mahmoodi
- Department of Immunology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abdollah Jafarzadeh
- Immunology of Infectious Diseases Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran; Department of Immunology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran; Department of Immunology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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Xu X, Zheng S, Xiong Y, Wang X, Qin W, Zhang H, Sun B. Adenosine effectively restores endotoxin-induced inhibition of human neutrophil chemotaxis via A1 receptor-p38 pathway. Inflamm Res 2017; 66:353-364. [PMID: 28074216 DOI: 10.1007/s00011-016-1021-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 12/17/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022] Open
Abstract
Neutrophil chemotaxis plays an essential role in recruiting neutrophils to sites of inflammation. Neutrophil chemotaxis is suppressed both after exposure to lipopolysaccharide (LPS) in vitro and during clinical and experimental endotoxemia, leading to serious consequences. Adenosine (ADO) is a potent anti-inflammatory agent that acts on a variety of neutrophil functions. However, its effects on human neutrophil chemotaxis during infection have been less well characterized. In the present study, we investigated the effect of ADO and its receptor-specific antagonist and agonist on neutrophil chemotaxis in an in vitro LPS-stimulated model. The results showed that increasing the concentration of ADO effectively restored the LPS-inhibited neutrophil chemotaxis to IL-8. A similar phenomenon occurred after intervention with a selective A1 receptor agonist but not with a selective antagonist. Pre-treatment with cAMP antagonist failed to restore LPS-inhibited chemotaxis. Furthermore, protein array and western blot analysis showed that the activation of A1 receptor significantly decreased LPS-induced p38 MAPK phosphorylation. However, the surface expression of the A1 receptor in LPS-stimulated neutrophils was not significantly changed. Taken together, these data indicated that ADO restored the LPS-inhibited chemotaxis via the A1 receptor, which downregulated the phosphorylation level of p38 MAPK, making this a promising new therapeutic strategy for infectious diseases.
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Affiliation(s)
- Xiaohan Xu
- Department of Burn and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Shuyun Zheng
- Department of Critical Care Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuyun Xiong
- Department of Clinical Laboratory, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Xu Wang
- Department of Burn and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Weiting Qin
- Department of Burn and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Huafeng Zhang
- Department of Burn and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Bingwei Sun
- Department of Burn and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu, China.
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Protective Effect of Cactus Cladode Extracts on Peroxisomal Functions in Microglial BV-2 Cells Activated by Different Lipopolysaccharides. Molecules 2017; 22:molecules22010102. [PMID: 28067864 PMCID: PMC6155690 DOI: 10.3390/molecules22010102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/28/2016] [Accepted: 01/04/2017] [Indexed: 11/22/2022] Open
Abstract
In this study, we aimed to evaluate the antioxidant and anti-inflammatory properties of Opuntia ficus-indica cactus cladode extracts in microglia BV-2 cells. Inflammation associated with microglia activation in neuronal injury can be achieved by LPS exposure. Using four different structurally and biologically well-characterized LPS serotypes, we revealed a structure-related differential effect of LPS on fatty acid β-oxidation and antioxidant enzymes in peroxisomes: Escherichia coli-LPS decreased ACOX1 activity while Salmonella minnesota-LPS reduced only catalase activity. Different cactus cladode extracts showed an antioxidant effect through microglial catalase activity activation and an anti-inflammatory effect by reducing nitric oxide (NO) LPS-dependent production. These results suggest that cactus extracts may possess a neuroprotective activity through the induction of peroxisomal antioxidant activity and the inhibition of NO production by activated microglial cells.
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Pieterse E, Rother N, Yanginlar C, Hilbrands LB, van der Vlag J. Neutrophils Discriminate between Lipopolysaccharides of Different Bacterial Sources and Selectively Release Neutrophil Extracellular Traps. Front Immunol 2016; 7:484. [PMID: 27867387 PMCID: PMC5095130 DOI: 10.3389/fimmu.2016.00484] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 10/21/2016] [Indexed: 01/26/2023] Open
Abstract
The release of neutrophil extracellular traps (NETs), either during "suicidal" or "vital" NETosis, represents an important strategy of neutrophils to combat Gram-negative bacteria. Lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria, is a reported stimulus for NET formation. Although it is widely acknowledged that the structural diversity in LPS structures can elicit heterogeneous immune responses, species- and serotype-specific differences in the capacity of LPS to trigger NET formation have not yet been investigated. In the present study, we compared the NET-inducing potential of LPS derived from Escherichia coli (serotypes O55:B5, O127:B8, O128:B12, O111:B4, and O26:B6), Salmonella enterica (serotype enteritidis), and Pseudomonas aeruginosa (serotype 10), under platelet-free and platelet-rich conditions in vitro, and in whole blood ex vivo. Here, we demonstrate that under serum- and platelet-free conditions, mimicking tissue circumstances, neutrophils discriminate between LPS of different bacterial sources and selectively release NETs only in response to LPS derived from E. coli O128:B12 and P. aeruginosa 10, which both induced "suicidal" NETosis in an autophagy- and reactive oxygen species (ROS)-dependent, but TLR4-independent manner. Intriguingly, in whole blood cultures ex vivo, or in vitro in the presence of platelets, all LPS serotypes induced "vital" NET formation. This platelet-dependent release of NETs occurred rapidly without neutrophil cell death and was independent from ROS formation and autophagy but required platelet TLR4 and CD62P-dependent platelet-neutrophil interactions. Taken together, our data reveal a complex interplay between neutrophils and LPS, which can induce both "suicidal" and "vital" NETosis, depending on the bacterial origin of LPS and the presence or absence of platelets. Our findings suggest that LPS sensing by neutrophils may be a critical determinant for restricting NET release to certain Gram-negative bacteria only, which in turn may be crucial for minimizing unnecessary NET-associated immunopathology.
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Affiliation(s)
- Elmar Pieterse
- Department of Nephrology, Radboud University Medical Center , Nijmegen , Netherlands
| | - Nils Rother
- Department of Nephrology, Radboud University Medical Center , Nijmegen , Netherlands
| | - Cansu Yanginlar
- Department of Nephrology, Radboud University Medical Center , Nijmegen , Netherlands
| | - Luuk B Hilbrands
- Department of Nephrology, Radboud University Medical Center , Nijmegen , Netherlands
| | - Johan van der Vlag
- Department of Nephrology, Radboud University Medical Center , Nijmegen , Netherlands
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Verhoeve VI, Jirakanwisal K, Utsuki T, Macaluso KR. Differential Rickettsial Transcription in Bloodfeeding and Non-Bloodfeeding Arthropod Hosts. PLoS One 2016; 11:e0163769. [PMID: 27662479 PMCID: PMC5035074 DOI: 10.1371/journal.pone.0163769] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 09/14/2016] [Indexed: 11/21/2022] Open
Abstract
Crucial factors influencing the epidemiology of Rickettsia felis rickettsiosis include pathogenesis and transmission. Detection of R. felis DNA in a number of arthropod species has been reported, with characterized isolates, R. felis strain LSU and strain LSU-Lb, generated from the cat flea, Ctenocephalides felis, and the non-hematophagous booklouse, Liposcelis bostrychophila, respectively. While it is realized that strain influence on host biology varies, the rickettsial response to these distinct host environments remained undefined. To identify a panel of potential rickettsial transmission determinants in the cat flea, the transcriptional profile for these two strains of R. felis were compared in their arthropod hosts using RNAseq. Rickettsial genes with increased transcription in the flea as compared to the booklouse were identified. Genes previously associated with bacterial virulence including LPS biosynthesis, Type IV secretion system, ABC transporters, and a toxin-antitoxin system were selected for further study. Transcription of putative virulence-associated genes was determined in a flea infection bioassay for both strains of R. felis. A host-dependent transcriptional profile during bloodfeeding, specifically, an increased expression of selected transcripts in newly infected cat fleas and flea feces was detected when compared to arthropod cell culture and incubation in vertebrate blood. Together, these studies have identified novel, host-dependent rickettsial factors that likely contribute to successful horizontal transmission by bloodfeeding arthropods.
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Affiliation(s)
- Victoria I. Verhoeve
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Krit Jirakanwisal
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Tadanobu Utsuki
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Kevin R. Macaluso
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
- * E-mail:
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116
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Wang D, Liu Y, Zhao YR, Zhou JL. Low dose of lipopolysaccharide pretreatment can alleviate the in?ammatory response in wound infection mouse model. Chin J Traumatol 2016; 19:193-8. [PMID: 27578373 PMCID: PMC4992131 DOI: 10.1016/j.cjtee.2016.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To assess the effects of lipopolysaccharide (LPS) pretreatment on wound infection mouse model and evaluate the biological safety of the optimal pretreatment dose in vivo. METHODS Mice were pretreated with LPS of different doses at 48 and 24 h before femoral medial lon- gitudinal incision was made and infected with different bacteria. RESULTS It is showed that 0.5 mg/kg/time of LPS pretreatment can significantly alleviate the inflammation in mouse model infected with methicillin-resistances Staphylococcus aureus, methicillin-sensitive S. aureus, Pseudomonas aeruginosa,or Escherichia coli compared with doses of 0.25 mg/kg/time, 1 mg/ kg/time, and 1.5 mg/kg/time. CONCLUSIONS LPS pretreatment can alleviate the inflammation in mouse model and the optimal dose is 0.5 mg/kg/time, and meanwhile it does not damage organs' function.
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117
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Sándor V, Kilár A, Kilár F, Kocsis B, Dörnyei Á. Characterization of complex, heterogeneous lipid A samples using HPLC-MS/MS technique II. Structural elucidation of non-phosphorylated lipid A by negative-ion mode tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2016; 51:615-628. [PMID: 28239963 DOI: 10.1002/jms.3786] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 05/09/2016] [Accepted: 05/11/2016] [Indexed: 06/06/2023]
Abstract
Non-phosphorylated lipid A species confer reduced inflammatory potential for the bacteria. Knowledge on their chemical structure and presence in bacterial pathogens may contribute to the understanding of bacterial resistance and activation of the host innate immune system. In this study, we report the fragmentation pathways of negatively charged, non-phosphorylated lipid A species under low-energy collision-induced dissociation conditions of an electrospray ionization quadrupole time-of-flight instrument. Charge-promoted consecutive and competitive eliminations of the acyl chains and cross-ring cleavages of the sugar residues were observed. The A-type fragment ion series and the complementary X-type fragment(s) with corresponding deprotonated carboxamide(s) were diagnostic for the distribution of the primary and secondary acyl residues on the non-reducing and the reducing ends, respectively, of the non-phosphorylated lipid A backbone. Reversed-phase liquid chromatography in combination with negative-ion electrospray ionization quadrupole time-of-flight tandem mass spectrometry could provide sufficient information on the primary and secondary acyl residues of a non-phosphorylated lipid A. As a standard, the hexa-acylated ion at m/z 1636 with the Escherichia coli-type acyl distribution (from E. coli O111) was used. The method was tested and refined with the analysis of other non-phosphorylated hexa- and several hepta-, penta-, and tetra-acylated lipid A species detected in crude lipid A fractions from E. coli O111 and Proteus morganii O34 bacteria. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Viktor Sándor
- Institute of Bioanalysis and Szentágothai Research Centre, University of Pécs, Szigeti út 12., 7624, Pécs, Hungary
| | - Anikó Kilár
- MTA-PTE Molecular Interactions in Separation Science Research Group, Ifjúság útja 6., 7624, Pécs, Hungary
| | - Ferenc Kilár
- Institute of Bioanalysis and Szentágothai Research Centre, University of Pécs, Szigeti út 12., 7624, Pécs, Hungary
- Department of Analytical and Environmental Chemistry, Faculty of Sciences, University of Pécs, Ifjúság útja 6., 7624, Pécs, Hungary
| | - Béla Kocsis
- Department of Medical Microbiology and Immunology, Faculty of Medicine, University of Pécs, Szigeti út 12., 7624, Pécs, Hungary
| | - Ágnes Dörnyei
- Department of Analytical and Environmental Chemistry, Faculty of Sciences, University of Pécs, Ifjúság útja 6., 7624, Pécs, Hungary
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118
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Vivoli M, Isupov MN, Nicholas R, Hill A, Scott AE, Kosma P, Prior JL, Harmer NJ. Unraveling the B. pseudomallei Heptokinase WcbL: From Structure to Drug Discovery. ACTA ACUST UNITED AC 2016; 22:1622-32. [PMID: 26687481 PMCID: PMC4691232 DOI: 10.1016/j.chembiol.2015.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/20/2015] [Accepted: 10/31/2015] [Indexed: 11/25/2022]
Abstract
Gram-negative bacteria utilize heptoses as part of their repertoire of extracellular polysaccharide virulence determinants. Disruption of heptose biosynthesis offers an attractive target for novel antimicrobials. A critical step in the synthesis of heptoses is their 1-O phosphorylation, mediated by kinases such as HldE or WcbL. Here, we present the structure of WcbL from Burkholderia pseudomallei. We report that WcbL operates through a sequential ordered Bi-Bi mechanism, loading the heptose first and then ATP. We show that dimeric WcbL binds ATP anti-cooperatively in the absence of heptose, and cooperatively in its presence. Modeling of WcbL suggests that heptose binding causes an elegant switch in the hydrogen-bonding network, facilitating the binding of a second ATP molecule. Finally, we screened a library of drug-like fragments, identifying hits that potently inhibit WcbL. Our results provide a novel mechanism for control of substrate binding and emphasize WcbL as an attractive anti-microbial target for Gram-negative bacteria.
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Affiliation(s)
- Mirella Vivoli
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Michail N Isupov
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Rebecca Nicholas
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Andrew Hill
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Andrew E Scott
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| | - Paul Kosma
- University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Joann L Prior
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| | - Nicholas J Harmer
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK.
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119
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The effect of growth temperature on the nanoscale biochemical surface properties of Yersinia pestis. Anal Bioanal Chem 2016; 408:5585-91. [PMID: 27259520 DOI: 10.1007/s00216-016-9659-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/17/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
Abstract
Yersinia pestis, the causative agent of plague, has been responsible for several recurrent, lethal pandemics in history. Currently, it is an important pathogen to study owing to its virulence, adaptation to different environments during transmission, and potential use in bioterrorism. Here, we report on the changes to Y. pestis surfaces in different external microenvironments, specifically culture temperatures (6, 25, and 37 °C). Using nanoscale imaging coupled with functional mapping, we illustrate that changes in the surfaces of the bacterium from a morphological and biochemical standpoint can be analyzed simultaneously using atomic force microscopy. The results from functional mapping, obtained at a single cell level, show that the density of lipopolysaccharide (measured via terminal N-acetylglucosamine) on Y. pestis grown at 37 °C is only slightly higher than cells grown at 25 °C, but nearly three times higher than cells maintained at 6 °C for an extended period of time, thereby demonstrating that adaptations to different environments can be effectively captured using this technique. This nanoscale evaluation provides a new microscopic approach to study nanoscale properties of bacterial pathogens and investigate adaptations to different external environments.
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120
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Expression and Function of miR-155 in Diseases of the Gastrointestinal Tract. Int J Mol Sci 2016; 17:ijms17050709. [PMID: 27187359 PMCID: PMC4881531 DOI: 10.3390/ijms17050709] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 04/25/2016] [Accepted: 05/03/2016] [Indexed: 12/30/2022] Open
Abstract
MicroRNAs (miRNAs) are a type of small noncoding RNA that can regulate the expression of target genes under physiological and pathophysiological conditions. miR-155 is a multifunctional miRNA with inflammation-related and oncogenic roles. In particular, the dysregulation of miR-155 has been strongly implicated in Helicobacter pylori-related gastric disease, inflammatory bowel disease, and colorectal cancer in addition to being involved in molecular changes of important targets and signaling pathways. This review focuses on the expression and function of miR-155 during inflammation and carcinogenesis and its potential use as an effective therapeutic target for certain gastrointestinal diseases.
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Almostafa M, Allehyane B, Egli S, Bottaro C, Fridgen TD, Banoub J. Tandem mass spectrometry determination of the putative structure of a heterogeneous mixture of Lipid As isolated from the lipopolysaccharide of the Gram-negative bacteria Aeromonas liquefaciens SJ-19a. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:1043-1058. [PMID: 27003042 DOI: 10.1002/rcm.7540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/03/2016] [Accepted: 02/12/2016] [Indexed: 06/05/2023]
Abstract
RATIONALE We report herein the electrospray ionization mass spectrometry (ESI-MS) and low-energy collision-induced dissociation tandem mass spectrometry analysis (CID-MS/MS) of a mixture of lipid As isolated from the rough lipopolysaccharide (LPS) of the mutant wild strain of the Gram-negative bacteria Aeromonas liquefaciens (SJ-19a, resistant) grown in the presence of phages. The interaction between the phages and the Gram-negative bacteria regulates host specificity and the heterogeneity of the lipid A component of the LPS. METHODS The heterogeneous mixture of lipid As was isolated by the aqueous phenol method from the LPS of the rough wild strain of Gram-negative bacteria Aeromonas liquefaciens (SJ-19a). Hydrolysis of the LPS was with 1% acetic acid, and purification was by chromatography using Sephadex G-50 and Sephadex G-15. ESI-MS and low-energy CID-MS/MS analyses were performed with a triple-quadrupole (QqQ) and a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. RESULTS Preliminary analysis of the lipid As mixture was conducted by ESI-MS in the negative ion mode and the spectrum obtained suggested that the lipid A SJ-19a was composed of a heterogeneous mixture of different lipid A molecules. CID-MS/MS experiments confirmed the identities of the various mono-phosphorylated β-D-GlcpN-(1→6)-α-D-GlcpN disaccharide entities. This lipid As mixture was asymmetrically substituted with fatty acids such as ((R)-14:0(3-OH)), (14:0(3-(R)-(O-12:0)) and (14:0(3-(R)-O-(14:0)) located on the O-3, O-3', N-2 and N-2' positions, respectively. CONCLUSIONS Low-energy collision-induced dissociation tandem mass spectrometry in-space (QqQ-MS/MS) and in-time (FTICR-MS/MS) allowed the exact determination of the fatty acid acylation positions on the H2 PO3 →4-O'-β-D-GlcpN-(1→6)-α-D-GlcpN disaccharide backbones of this heterogeneous mixture of lipid As , composed inter alia of seven different substituted lipid As , formed from the incomplete biosynthesis of their respective LPS.
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Affiliation(s)
- Mervt Almostafa
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Bashaeer Allehyane
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Stefana Egli
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Christina Bottaro
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Travis D Fridgen
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Joseph Banoub
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
- Special Projects, Science Branch, Department of Fisheries and Oceans Canada, St. John's, Newfoundland, Canada
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Kamaladevi A, Balamurugan K. Lipopolysaccharide of Klebsiella pneumoniae attenuates immunity of Caenorhabditis elegans and evades by altering its supramolecular structure. RSC Adv 2016. [DOI: 10.1039/c5ra18206a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Given the prominence of lipopolysaccharide (LPS) in the pathogenesis of Gram-negative bacteria, investigations at the molecular level in in vivo conditions are in dire need to understand its role in provoking infection.
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Affiliation(s)
- Arumugam Kamaladevi
- Department of Biotechnology
- Science Campus
- Alagappa University
- Karaikudi 630 004
- India
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Carter MD, Miller DS, Jennings J, Wang X, Mahanthappa MK, Abbott NL, Lynn DM. Synthetic Mimics of Bacterial Lipid A Trigger Optical Transitions in Liquid Crystal Microdroplets at Ultralow Picogram-per-Milliliter Concentrations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12850-12855. [PMID: 26562069 PMCID: PMC4671391 DOI: 10.1021/acs.langmuir.5b03557] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/11/2015] [Indexed: 05/29/2023]
Abstract
We report synthetic six-tailed mimics of the bacterial glycolipid Lipid A that trigger changes in the internal ordering of water-dispersed liquid crystal (LC) microdroplets at ultralow (picogram-per-milliliter) concentrations. These molecules represent the first class of synthetic amphiphiles to mimic the ability of Lipid A and bacterial endotoxins to trigger optical responses in LC droplets at these ultralow concentrations. This behavior stands in contrast to all previously reported synthetic surfactants and lipids, which require near-complete monolayer coverage at the LC droplet surface to trigger ordering transitions. Surface-pressure measurements and SAXS experiments reveal these six-tailed synthetic amphiphiles to mimic key aspects of the self-assembly of Lipid A at aqueous interfaces and in solution. These and other results suggest that these amphiphiles trigger orientational transitions at ultralow concentrations through a unique mechanism that is similar to that of Lipid A and involves formation of inverted self-associated nanostructures at topological defects in the LC droplets.
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Affiliation(s)
- Matthew
C. D. Carter
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Daniel S. Miller
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - James Jennings
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Xiaoguang Wang
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Mahesh K. Mahanthappa
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Nicholas L. Abbott
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - David M. Lynn
- Department
of Chemistry, and Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
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Balasubramanian K, Maeda A, Lee JS, Mohammadyani D, Dar HH, Jiang JF, St Croix CM, Watkins S, Tyurin VA, Tyurina YY, Klöditz K, Polimova A, Kapralova VI, Xiong Z, Ray P, Klein-Seetharaman J, Mallampalli RK, Bayir H, Fadeel B, Kagan VE. Dichotomous roles for externalized cardiolipin in extracellular signaling: Promotion of phagocytosis and attenuation of innate immunity. Sci Signal 2015; 8:ra95. [PMID: 26396268 PMCID: PMC4760701 DOI: 10.1126/scisignal.aaa6179] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Among the distinct molecular signatures present in the mitochondrion is the tetra-acylated anionic phospholipid cardiolipin, a lipid also present in primordial, single-cell bacterial ancestors of mitochondria and multiple bacterial species today. Cardiolipin is normally localized to the inner mitochondrial membrane; however, when cardiolipin becomes externalized to the surface of dysregulated mitochondria, it promotes inflammasome activation and stimulates the elimination of damaged or nonfunctional mitochondria by mitophagy. Given the immunogenicity of mitochondrial and bacterial membranes that are released during sterile and pathogen-induced trauma, we hypothesized that cardiolipins might function as "eat me" signals for professional phagocytes. In experiments with macrophage cell lines and primary macrophages, we found that membranes with mitochondrial or bacterial cardiolipins on their surface were engulfed through phagocytosis, which depended on the scavenger receptor CD36. Distinct from this process, the copresentation of cardiolipin with the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide dampened TLR4-stimulated production of cytokines. These data suggest that externalized, extracellular cardiolipins play a dual role in host-host and host-pathogen interactions by promoting phagocytosis and attenuating inflammatory immune responses.
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Affiliation(s)
- Krishnakumar Balasubramanian
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
| | - Akihiro Maeda
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Janet S Lee
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Dariush Mohammadyani
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Haider Hussain Dar
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Jian Fei Jiang
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Claudette M St Croix
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon Watkins
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Vladimir A Tyurin
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Katharina Klöditz
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Anastassia Polimova
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Valentyna I Kapralova
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Zeyu Xiong
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Prabir Ray
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | | | - Rama K Mallampalli
- Department of Internal Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA. Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA 15215, USA
| | - Hülya Bayir
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA. Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Bengt Fadeel
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden.
| | - Valerian E Kagan
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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125
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Putting on the brakes: Bacterial impediment of wound healing. Sci Rep 2015; 5:14003. [PMID: 26365869 PMCID: PMC4650533 DOI: 10.1038/srep14003] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 12/17/2022] Open
Abstract
The epithelium provides a crucial barrier to infection, and its integrity requires
efficient wound healing. Bacterial cells and secretomes from a subset of tested
species of bacteria inhibited human and porcine corneal epithelial cell migration
in vitro and ex vivo. Secretomes from 95% of Serratia
marcescens, 71% of Pseudomonas aeruginosa, 29% of Staphylococcus
aureus strains, and other bacterial species inhibited epithelial cell
migration. Migration of human foreskin fibroblasts was also inhibited by S.
marcescens secretomes indicating that the effect is not cornea specific.
Transposon mutagenesis implicated lipopolysaccharide (LPS) core biosynthetic genes
as being required to inhibit corneal epithelial cell migration. LPS depletion of
S. marcescens secretomes with polymyxin B agarose rendered secretomes
unable to inhibit epithelial cell migration. Purified LPS from S. marcescens,
but not from Escherichia coli or S. marcescens strains with mutations
in the waaG and waaC genes, inhibited epithelial cell migration in
vitro and wound healing ex vivo. Together these data suggest that
S. marcescens LPS is sufficient for inhibition of epithelial wound
healing. This study presents a novel host-pathogen interaction with implications for
infections where bacteria impact wound healing and provides evidence that secreted
LPS is a key factor in the inhibitory mechanism.
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126
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Liao C, Liang X, Soupir M, Jarboe L. Cellular, particle and environmental parameters influencing attachment in surface waters: a review. J Appl Microbiol 2015; 119:315-30. [DOI: 10.1111/jam.12860] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/04/2015] [Accepted: 05/14/2015] [Indexed: 11/30/2022]
Affiliation(s)
- C. Liao
- Chemical and Biological Engineering; Iowa State University; Ames IA USA
- Interdepartmental Microbiology Program; Iowa State University; Ames IA USA
| | - X. Liang
- Agricultural and Biosystems Engineering; Iowa State University; Ames IA USA
| | - M.L. Soupir
- Agricultural and Biosystems Engineering; Iowa State University; Ames IA USA
| | - L.R. Jarboe
- Chemical and Biological Engineering; Iowa State University; Ames IA USA
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127
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Coccia EM, Battistini A. Early IFN type I response: Learning from microbial evasion strategies. Semin Immunol 2015; 27:85-101. [PMID: 25869307 PMCID: PMC7129383 DOI: 10.1016/j.smim.2015.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/10/2015] [Indexed: 12/12/2022]
Abstract
Type I interferon (IFN) comprises a class of cytokines first discovered more than 50 years ago and initially characterized for their ability to interfere with viral replication and restrict locally viral propagation. As such, their induction downstream of germ-line encoded pattern recognition receptors (PRRs) upon recognition of pathogen-associated molecular patterns (PAMPs) is a hallmark of the host antiviral response. The acknowledgment that several PAMPs, not just of viral origin, may induce IFN, pinpoints at these molecules as a first line of host defense against a number of invading pathogens. Acting in both autocrine and paracrine manner, IFN interferes with viral replication by inducing hundreds of different IFN-stimulated genes with both direct anti-pathogenic as well as immunomodulatory activities, therefore functioning as a bridge between innate and adaptive immunity. On the other hand an inverse interference to escape the IFN system is largely exploited by pathogens through a number of tactics and tricks aimed at evading, inhibiting or manipulating the IFN pathway, that result in progression of infection or establishment of chronic disease. In this review we discuss the interplay between the IFN system and some selected clinically important and challenging viruses and bacteria, highlighting the wide array of pathogen-triggered molecular mechanisms involved in evasion strategies.
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Affiliation(s)
- Eliana M Coccia
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | - Angela Battistini
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy.
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128
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Li MF, Sun L, Li J. Edwardsiella tarda evades serum killing by preventing complement activation via the alternative pathway. FISH & SHELLFISH IMMUNOLOGY 2015; 43:325-329. [PMID: 25575477 DOI: 10.1016/j.fsi.2014.12.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/01/2014] [Accepted: 12/26/2014] [Indexed: 06/04/2023]
Abstract
Edwardsiella tarda is a Gram-negative bacterium with a broad host range that includes a wide variety of farmed fish as well as humans. E. tarda has long been known to be able to survive in host serum, but the relevant mechanism is unclear. In this study, we investigated the fundamental question, i.e. whether E. tarda activated serum complement or not. We found that (i) when incubated with flounder serum, E. tarda exhibited a high survival rate (87.6%), which was slightly but significantly reduced in the presence of Mg(2+); (ii) E. tarda-incubated serum possessed strong hemolytic activity and bactericidal activity, (iii) compared to the serum incubated with a complement-sensitive laboratory Escherichia coli strain, E. tarda-incubated serum exhibited much less chemotactic activity, (iv) in contrast to the serum incubated with live E. tarda, the serum incubated with heat-inactivated E. tarda exhibited no apparent hemolytic capacity. Taken together, these results indicate for the first time that E. tarda circumvents serum attack by preventing, to a large extent, complement activation via the alternative pathway, and that heat-labile surface structures likely play an essential role in the complement evasion of E. tarda.
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Affiliation(s)
- Mo-fei Li
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Li Sun
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
| | - Jun Li
- School of Biological Sciences, Lake Superior State University, 650 W. Easterday Ave., Sault Ste Marie, MI 49783, USA.
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129
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Effect of Helicobacter pylori eradication on TLR2 and TLR4 expression in patients with gastric lesions. Mediators Inflamm 2015; 2015:481972. [PMID: 25873761 PMCID: PMC4385704 DOI: 10.1155/2015/481972] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 03/04/2015] [Accepted: 03/06/2015] [Indexed: 12/20/2022] Open
Abstract
Objective. Helicobacter pylori (Hp) is recognized by TLR4 and TLR2 receptors, which trigger the activation of genes involved in the host immune response. Thus, we evaluated the effect of eradication therapy on TLR2 and TLR4 mRNA and protein expression in H. pylori-infected chronic gastritis patients (CG-Hp+) and 3 months after treatment. Methods. A total of 37 patients CG-Hp+ were evaluated. The relative quantification (RQ) of mRNA was assessed by TaqMan assay and protein expression by immunohistochemistry. Results. Before treatment both TLR2 and TLR4 mRNA in CG-Hp+ patients were slightly increased (TLR2 = 1.32; TLR4 = 1.26) in relation to Hp-negative normal gastric mucosa (P ≤ 0.05). After successful eradication therapy no significant change was observed (TLR2 = 1.47; TLR4 = 1.53; P > 0.05). In addition, the cagA and vacA bacterial genotypes did not influence the gene expression levels, and we observed a positive correlation between the RQ values of TLR2 and TLR4, both before and after treatment. Immunoexpression of the TLR2 and TLR4 proteins confirmed the gene expression results. Conclusion. In conclusion, the expression of both TLR2 and TLR4 is increased in CG-Hp+ patients regardless of cagA and vacA status and this expression pattern is not significantly changed after eradication of bacteria, at least for the short period of time evaluated.
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130
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Phenotypic heterogeneity enables uropathogenic Escherichia coli to evade killing by antibiotics and serum complement. Infect Immun 2015; 83:1056-67. [PMID: 25561706 DOI: 10.1128/iai.02725-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Uropathogenic strains of Escherichia coli (UPEC) are the major cause of bacteremic urinary tract infections. Survival in the bloodstream is associated with different mechanisms that help to resist serum complement-mediated killing. While the phenotypic heterogeneity of bacteria has been shown to influence antibiotic tolerance, the possibility that it makes cells refractory to killing by the immune system has not been experimentally tested. In the present study we sought to determine whether the heterogeneity of bacterial cultures is relevant to bacterial targeting by the serum complement system. We monitored cell divisions in the UPEC strain CFT073 with fluorescent reporter protein. Stationary-phase cells were incubated in active or heat-inactivated human serum in the presence or absence of different antibiotics (ampicillin, norfloxacin, and amikacin), and cell division and complement protein C3 binding were measured by flow cytometry and immunofluorescence microscopy. Heterogeneity in the doubling times of CFT073 cells in serum enabled three phenotypically different subpopulations to be distinguished, all of them being recognized by the C3 component of the complement system. The population of rapidly growing cells resists serum complement-mediated lysis. The dominant subpopulation of cells with intermediate growth rate is susceptible to serum. The third population, which does not resume growth upon dilution from stationary phase, is simultaneously protected from serum complement and antibiotics.
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131
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Ng SK, Huang YT, Lee YC, Low EL, Chiu CH, Chen SL, Mao LC, Chang MDT. A recombinant horseshoe crab plasma lectin recognizes specific pathogen-associated molecular patterns of bacteria through rhamnose. PLoS One 2014; 9:e115296. [PMID: 25541995 PMCID: PMC4277298 DOI: 10.1371/journal.pone.0115296] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 11/21/2014] [Indexed: 11/18/2022] Open
Abstract
Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs) on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens.
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Affiliation(s)
- Sim-Kun Ng
- Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Yu-Tsyr Huang
- Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Yuan-Chuan Lee
- Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Ee-Ling Low
- Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Cheng-Hsun Chiu
- Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan Hsien, Taiwan, Republic of China
| | - Shiu-Ling Chen
- Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan Hsien, Taiwan, Republic of China
| | - Liang-Chi Mao
- Simpson Biotech Co., Ltd., Kuei Shan, Taoyuan County, Taiwan, Republic of China
| | - Margaret Dah-Tsyr Chang
- Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
- * E-mail:
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Menanteau-Ledouble S, Soliman H, Kumar G, El-Matbouli M. Use of in vivo induced antigen technology to identify genes from Aeromonas salmonicida subsp. salmonicida that are specifically expressed during infection of the rainbow trout Oncorhynchus mykiss. BMC Vet Res 2014; 10:298. [PMID: 25495705 PMCID: PMC4269963 DOI: 10.1186/s12917-014-0298-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 12/08/2014] [Indexed: 02/02/2023] Open
Abstract
Background Aeromonas salmonicida is a major fish pathogen associated with mass mortalities in salmonid fish. In the present study, we applied In Vivo Induced Antigen Technology (IVIAT), a technique that relies on antibodies adsorbed against in vitro cultures of the pathogen, to a clinical isolate of A. salmonicida subsp. salmonicida. Results The results from IVIAT allowed identification of four proteins that were upregulated in the fish samples: A UDP-3-O-acyl-N-acetylglucosamine deacetylase, an RNA polymerase sigma factor D as well as TonB and a hypothetical protein. Subsequent investigations were performed using real-time PCR and cDNA synthesised from infected spleen, liver and anterior kidneys. These confirmed that the transcription level of each of these genes was significantly upregulated during the infection process compared to bacteria in vitro. Conclusions The present studied identified four genes that were upregulated during the infectious process and are likely to play a role in the virulence of A. salmonicida. Because these are antigenic they might constitute potential targets for the development of new vaccine as well as therapeutic agents.
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Affiliation(s)
- Simon Menanteau-Ledouble
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinarplatz 1, Vienna, 1210, Austria.
| | - Hatem Soliman
- Fish Medicine and Managements, Department of Animal Medicine, Faculty of Veterinary Medicine, Assiut University, 71515, Assiut, Egypt.
| | - Gokhlesh Kumar
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinarplatz 1, Vienna, 1210, Austria.
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinarplatz 1, Vienna, 1210, Austria.
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133
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Bay DC, Booth SC, Turner RJ. Respiration and ecological niche influence bacterial membrane lipid compositions. Environ Microbiol 2014; 17:1777-93. [DOI: 10.1111/1462-2920.12637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/22/2014] [Accepted: 09/22/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Denice C. Bay
- Department of Biological Sciences; University of Calgary; Calgary AB T2N 1N4 Canada
| | - Sean C. Booth
- Department of Biological Sciences; University of Calgary; Calgary AB T2N 1N4 Canada
| | - Raymond J. Turner
- Department of Biological Sciences; University of Calgary; Calgary AB T2N 1N4 Canada
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134
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Bordetella pertussis naturally occurring isolates with altered lipooligosaccharide structure fail to fully mature human dendritic cells. Infect Immun 2014; 83:227-38. [PMID: 25348634 DOI: 10.1128/iai.02197-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bordetella pertussis is a Gram-negative bacterium and the causative agent of whooping cough. Despite high vaccination coverage, outbreaks are being increasingly reported worldwide. Possible explanations include adaptation of this pathogen, which may interfere with recognition by the innate immune system. Here, we describe innate immune recognition and responses to different B. pertussis clinical isolates. By using HEK-Blue cells transfected with different pattern recognition receptors, we found that 3 out of 19 clinical isolates failed to activate Toll-like receptor 4 (TLR4). These findings were confirmed by using the monocytic MM6 cell line. Although incubation with high concentrations of these 3 strains resulted in significant activation of the MM6 cells, it was found to occur mainly through interaction with TLR2 and not through TLR4. When using live bacteria, these 3 strains also failed to activate TLR4 on HEK-Blue cells, and activation of MM6 cells or human monocyte-derived dendritic cells was significantly lower than activation induced by the other 16 strains. Mass spectrum analysis of the lipid A moieties from these 3 strains indicated an altered structure of this molecule. Gene sequence analysis revealed mutations in genes involved in lipid A synthesis. Findings from this study indicate that B. pertussis isolates that do not activate TLR4 occur naturally and that this phenotype may give this bacterium an advantage in tempering the innate immune response and establishing infection. Knowledge on the strategies used by this pathogen in evading the host immune response is essential for the improvement of current vaccines or for the development of new ones.
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135
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Smith SM. Role of Toll-like receptors in Helicobacter pylori infection and immunity. World J Gastrointest Pathophysiol 2014; 5:133-146. [PMID: 25133016 PMCID: PMC4133513 DOI: 10.4291/wjgp.v5.i3.133] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/25/2014] [Accepted: 05/19/2014] [Indexed: 02/07/2023] Open
Abstract
The gram-negative bacterium Helicobacter pylori (H. pylori) infects the stomachs of approximately half of the world’s population. Although infection induces an immune response that contributes to chronic gastric inflammation, the response is not sufficient to eliminate the bacterium. H. pylori infection causes peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Disease outcome is linked to the severity of the host inflammatory response. Gastric epithelial cells represent the first line of innate immune defence against H. pylori, and respond to infection by initiating numerous cell signalling cascades, resulting in cytokine induction and the subsequent recruitment of inflammatory cells to the gastric mucosa. Pathogen recognition receptors of the Toll-like receptor (TLR) family mediate many of these cell signalling events. This review discusses recent findings on the role of various TLRs in the recognition of H. pylori in distinct cell types, describes the TLRs responsible for the recognition of individual H. pylori components and outlines the influence of innate immune activation on the subsequent development of the adaptive immune response. The mechanistic identification of host mediators of H. pylori-induced pathogenesis has the potential to reveal drug targets and opportunities for therapeutic intervention or prevention of H. pylori-associated disease by means of vaccines or immunomodulatory therapy.
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Abstract
The innate immune system has evolved under selective pressure since the radiation of multicellular life approximately 600 million years ago. Because of this long history, innate immune mechanisms found in modern eukaryotic organisms today are highly complex but yet built from common molecular strategies. It is now clear that evolution has selected a conserved set of antimicrobial peptides as well as pattern-recognition receptors (PRRs) that initiate cellular-based signals as a first line of defense against invading pathogens. Conversely, microbial pathogens employ their own strategies in order to evade, inhibit, or otherwise manipulate the innate immune response. Here, we discuss recent discoveries that have changed our view of immune modulatory mechanisms employed by bacterial pathogens, focusing specifically on the initial sites of microbial recognition and extending to host cellular signal transduction, proinflammatory cytokine production, and alteration of protein trafficking and secretion.
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137
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Clark GF. The role of glycans in immune evasion: the human fetoembryonic defence system hypothesis revisited. Mol Hum Reprod 2014; 20:185-99. [PMID: 24043694 PMCID: PMC3925329 DOI: 10.1093/molehr/gat064] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/15/2013] [Accepted: 09/03/2013] [Indexed: 02/06/2023] Open
Abstract
Emerging data suggest that mechanisms to evade the human immune system may be shared by the conceptus, tumour cells, persistent pathogens and viruses. It is therefore timely to revisit the human fetoembryonic defense system (Hu-FEDS) hypothesis that was proposed in two papers in the 1990s. The initial paper suggested that glycoconjugates expressed in the human reproductive system inhibited immune responses directed against gametes and the developing human by employing their carbohydrate sequences as functional groups. These glycoconjugates were proposed to block specific binding interactions and interact with lectins linked to signal transduction pathways that modulated immune cell functions. The second article suggested that aggressive tumour cells and persistent pathogens (HIV, H. pylori, schistosomes) either mimicked or acquired the same carbohydrate functional groups employed in this system to evade immune responses. This subterfuge enabled these pathogens and tumour cells to couple their survival to the human reproductive imperative. The Hu-FEDS model has been repeatedly tested since its inception. Data relevant to this model have also been obtained in other studies. Herein, the Hu-FEDS hypothesis is revisited in the context of these more recent findings. Far more supportive evidence for this model now exists than when it was first proposed, and many of the original predictions have been validated. This type of subterfuge by pathogens and tumour cells likely applies to all sexually reproducing metazoans that must protect their gametes from immune responses. Intervention in these pathological states will likely remain problematic until this system of immune evasion is fully understood and appreciated.
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Affiliation(s)
- Gary F. Clark
- Department of Obstetrics, Gynecology and Women's Health, Division of Reproductive and Perinatal Research and Division of Reproductive Medicine and Fertility, University of Missouri School of Medicine, Columbia, MO 65211, USA
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138
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Kovalchuk O, Walz P, Kovalchuk I. Does bacterial infection cause genome instability and cancer in the host cell? Mutat Res 2014; 761:1-14. [PMID: 24472301 DOI: 10.1016/j.mrfmmm.2014.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/08/2013] [Accepted: 01/16/2014] [Indexed: 06/03/2023]
Abstract
Research of the past several decades suggests that bacterial infection can lead to genome instability of the host cell often resulting in cancer development. However, there is still a substantial lack of knowledge regarding possible mechanisms involved in the development of genomic instability. Several questions remain unanswered, namely: Why has the causative relationship between the bacterial infection and cancer been established only for a small number of cancers? What is the mechanism responsible for the induction of genome instability and cancer? Is the infection process required to cause genome instability and cancer? In this review, we present a hypothesis that the bacterial infection, exposure to heat-killed bacteria or even some bacterial determinants may trigger genome instability of exposed and distal cells, and thus may cause cancer. We will discuss the mechanisms of host responses to the bacterial infection and present the possible pathways leading to genome instability and cancer through exposure to bacteria.
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Affiliation(s)
- Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada.
| | - Paul Walz
- Department of Biological Sciences, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada.
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada.
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139
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Suarez G, Peek RM. Helicobacter pylori: expect the unexpected. Mol Microbiol 2014; 91:858-61. [PMID: 24471732 DOI: 10.1111/mmi.12532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Indexed: 12/26/2022]
Abstract
Helicobacter pylori is one of the most common bacterial infections worldwide, and virtually all infected persons develop coexisting gastritis, a signature feature of which is the capacity to persist for decades. In support of its lifestyle, H. pylori has evolved to express an array of diverse phenotypes, including enzyme functional diversity, that help to subvert obstacles presented by the human host, which permits long-term microbial colonization. The versatility of the newly discovered enzyme LpxJ may allow H. pylori to quickly adapt to dynamic and hostile conditions present within its cognate gastric niche.
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Affiliation(s)
- Giovanni Suarez
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, 37232, USA
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140
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Cadamuro ACT, Rossi AFT, Maniezzo NM, Silva AE. Helicobacter pylori infection: host immune response, implications on gene expression and microRNAs. World J Gastroenterol 2014; 20:1424-37. [PMID: 24587619 PMCID: PMC3925852 DOI: 10.3748/wjg.v20.i6.1424] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/18/2013] [Accepted: 01/03/2014] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori) infection is the most common bacterial infection worldwide. Persistent infection of the gastric mucosa leads to inflammatory processes and may remain silent for decades or progress causing more severe diseases, such as gastric adenocarcinoma. The clinical consequences of H. pylori infection are determined by multiple factors, including host genetic predisposition, gene regulation, environmental factors and heterogeneity of H. pylori virulence factors. After decades of studies of this successful relationship between pathogen and human host, various mechanisms have been elucidated. In this review, we have made an introduction on H. pylori infection and its virulence factors, and focused mainly on modulation of host immune response triggered by bacteria, changes in the pattern of gene expression in H. pylori-infected gastric mucosa, with activation of gene transcription involved in defense mechanisms, inflammatory and immunological response, cell proliferation and apoptosis. We also highlighted the role of bacteria eradication on gene expression levels. In addition, we addressed the recent involvement of different microRNAs in precancerous lesions, gastric cancer, and inflammatory processes induced by bacteria. New discoveries in this field may allow a better understanding of the role of major factors involved in the pathogenic mechanisms of H. pylori.
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141
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Xiao S, Zhao L. Gut microbiota-based translational biomarkers to prevent metabolic syndrome via nutritional modulation. FEMS Microbiol Ecol 2013; 87:303-14. [PMID: 24219358 PMCID: PMC4262049 DOI: 10.1111/1574-6941.12250] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 09/20/2013] [Accepted: 11/04/2013] [Indexed: 12/14/2022] Open
Abstract
In the face of the global epidemic of metabolic syndrome (MetS) and its strong association with the increasing rate of cardiovascular morbidity and mortality, it is critical to detect MetS at an early stage in the clinical setting to implement preventive intervention long before the complications arise. Lipopolysaccharide, the cell wall component of Gram-negative bacteria produced from diet-disrupted gut microbiota, has been shown to induce metabolic endotoxemia, chronic low-grade inflammation, and ultimately insulin resistance. Therefore, ameliorating the inflammation and insulin resistance underlying MetS by gut microbiota-targeted, dietary intervention has gained increasing attention. In this review, we propose using dynamic monitoring of a set of translational biomarkers related with the etiological role of gut microbiota, including lipopolysaccharide binding protein (LBP), C-reactive protein (CRP), fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR), for early detection and prevention of MetS via nutritional modulation. LBP initiates the recognition and monomerization of lipopolysaccharide and amplifies host immune responses, linking the gut-derived antigen load and inflammation indicated by the plasma levels of CRP. Fasting plasma insulin and HOMA-IR are measured to evaluate insulin sensitivity that is damaged by pro-inflammatory cytokines. The dynamic monitoring of these biomarkers in high-risk populations may provide translational methods for the quantitative and dynamic evaluation of dysbiosis-induced insulin resistance and the effectiveness of dietary treatment for MetS.
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Affiliation(s)
- Shuiming Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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