1
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Bemark M, Pitcher MJ, Dionisi C, Spencer J. Gut-associated lymphoid tissue: a microbiota-driven hub of B cell immunity. Trends Immunol 2024; 45:211-223. [PMID: 38402045 PMCID: PMC11227984 DOI: 10.1016/j.it.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/26/2024]
Abstract
The diverse gut microbiota, which is associated with mucosal health and general wellbeing, maintains gut-associated lymphoid tissues (GALT) in a chronically activated state, including sustainment of germinal centers in a context of high antigenic load. This influences the rules for B cell engagement with antigen and the potential consequences. Recent data have highlighted differences between GALT and other lymphoid tissues. For example, GALT propagates IgA responses against glycans that show signs of having been generated in germinal centers. Other findings suggest that humans are among those species where GALT supports the diversification, propagation, and possibly selection of systemic B cells. Here, we review novel findings that identify GALT as distinctive, and able to support these processes.
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Affiliation(s)
- Mats Bemark
- Department of Translational Medicine - Human Immunology, Lund University, J Waldenströms gata 35, Malmö, Sweden; Department of Clinical Immunology and Transfusion Medicine, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden.
| | - Michael J Pitcher
- Peter Gorer Department of Immunobiology, King's College London, Guy's Hospital Campus, St Thomas' Street, London SE1 9RT, UK
| | - Chiara Dionisi
- Peter Gorer Department of Immunobiology, King's College London, Guy's Hospital Campus, St Thomas' Street, London SE1 9RT, UK
| | - Jo Spencer
- Peter Gorer Department of Immunobiology, King's College London, Guy's Hospital Campus, St Thomas' Street, London SE1 9RT, UK.
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2
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Nandi I, Aroeti B. Mitogen-Activated Protein Kinases (MAPKs) and Enteric Bacterial Pathogens: A Complex Interplay. Int J Mol Sci 2023; 24:11905. [PMID: 37569283 PMCID: PMC10419152 DOI: 10.3390/ijms241511905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/19/2023] [Accepted: 07/19/2023] [Indexed: 08/13/2023] Open
Abstract
Diverse extracellular and intracellular cues activate mammalian mitogen-activated protein kinases (MAPKs). Canonically, the activation starts at cell surface receptors and continues via intracellular MAPK components, acting in the host cell nucleus as activators of transcriptional programs to regulate various cellular activities, including proinflammatory responses against bacterial pathogens. For instance, binding host pattern recognition receptors (PRRs) on the surface of intestinal epithelial cells to bacterial pathogen external components trigger the MAPK/NF-κB signaling cascade, eliciting cytokine production. This results in an innate immune response that can eliminate the bacterial pathogen. However, enteric bacterial pathogens evolved sophisticated mechanisms that interfere with such a response by delivering virulent proteins, termed effectors, and toxins into the host cells. These proteins act in numerous ways to inactivate or activate critical components of the MAPK signaling cascades and innate immunity. The consequence of such activities could lead to successful bacterial colonization, dissemination, and pathogenicity. This article will review enteric bacterial pathogens' strategies to modulate MAPKs and host responses. It will also discuss findings attempting to develop anti-microbial treatments by targeting MAPKs.
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Affiliation(s)
| | - Benjamin Aroeti
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190410, Israel;
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3
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Kang MJ, Jeong H, Kim S, Shin J, Song Y, Lee BH, Park HG, Lee TH, Jiang HH, Han YS, Lee BG, Lee HJ, Park MJ, Park YS. Structural analysis and prebiotic activity of exopolysaccharide produced by probiotic strain Bifidobacterium bifidum EPS DA-LAIM. Food Sci Biotechnol 2023; 32:517-529. [PMID: 36911335 PMCID: PMC9992680 DOI: 10.1007/s10068-022-01213-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/08/2022] [Accepted: 11/13/2022] [Indexed: 12/03/2022] Open
Abstract
Exopolysaccharide (EPS)-producing Bifidobacterium bifidum EPS DA-LAIM was isolated from healthy human feces, the structure of purified EPS from the strain was analyzed, and its prebiotic activity was evaluated. The EPS from B. bifidum EPS DA-LAIM is a glucomannan-type heteropolysaccharide with a molecular weight of 407-1007 kDa, and its structure comprises 2-mannosyl, 6-mannosyl, and 2,6-mannosyl residues. The purified EPS promoted the growth of representative lactic acid bacteria and bifidobacterial strains. Bifidobacterium bifidum EPS DA-LAIM increased nitric oxide production in RAW 264.7 macrophage cells, indicating its immunostimulatory activity. Bifidobacterium bifidum EPS DA-LAIM also exhibited high gastrointestinal tract tolerance, gut adhesion ability, and antioxidant activity. These results suggest that EPS from B. bifidum EPS DA-LAIM is a potentially useful prebiotic material, and B. bifidum EPS DA-LAIM could be applied as a probiotic candidate. Supplementary Information The online version contains supplementary material available at 10.1007/s10068-022-01213-w.
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Affiliation(s)
- Min Joo Kang
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
| | - Huijin Jeong
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
| | - Suin Kim
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
| | - Jaein Shin
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
| | - Youngbo Song
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
| | - Byung-Hoo Lee
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
| | - Hyoung-Geun Park
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Tae-Ho Lee
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Hai-Hua Jiang
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Young-Sun Han
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Bong-Gyeong Lee
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Ho-Jin Lee
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Min-Ju Park
- Research Laboratory, Dong-A Pharmaceutical Co., Ltd., Yongin, 17073 Republic of Korea
| | - Young-Seo Park
- Department of Food Science and Biotechnology, Gachon University, Seongnam, 13120 Republic of Korea
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4
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Rahmatelahi H, El-Matbouli M, Menanteau-Ledouble S. Delivering the pain: an overview of the type III secretion system with special consideration for aquatic pathogens. Vet Res 2021; 52:146. [PMID: 34924019 PMCID: PMC8684695 DOI: 10.1186/s13567-021-01015-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/08/2021] [Indexed: 11/10/2022] Open
Abstract
Gram-negative bacteria are known to subvert eukaryotic cell physiological mechanisms using a wide array of virulence factors, among which the type three-secretion system (T3SS) is often one of the most important. The T3SS constitutes a needle-like apparatus that the bacterium uses to inject a diverse set of effector proteins directly into the cytoplasm of the host cells where they can hamper the host cellular machinery for a variety of purposes. While the structure of the T3SS is somewhat conserved and well described, effector proteins are much more diverse and specific for each pathogen. The T3SS can remodel the cytoskeleton integrity to promote intracellular invasion, as well as silence specific eukaryotic cell signals, notably to hinder or elude the immune response and cause apoptosis. This is also the case in aquatic bacterial pathogens where the T3SS can often play a central role in the establishment of disease, although it remains understudied in several species of important fish pathogens, notably in Yersinia ruckeri. In the present review, we summarise what is known of the T3SS, with a special focus on aquatic pathogens and suggest some possible avenues for research including the potential to target the T3SS for the development of new anti-virulence drugs.
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Affiliation(s)
- Hadis Rahmatelahi
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210, Vienna, Austria
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210, Vienna, Austria
| | - Simon Menanteau-Ledouble
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210, Vienna, Austria.
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg Ø, Denmark.
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5
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Zou J, Liu C, Jiang S, Qian D, Duan J. Cross Talk between Gut Microbiota and Intestinal Mucosal Immunity in the Development of Ulcerative Colitis. Infect Immun 2021; 89:e0001421. [PMID: 33526559 PMCID: PMC8370674 DOI: 10.1128/iai.00014-21] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Ulcerative colitis (UC), a nonspecific inflammatory disease, is characterized by inflammation and mucosal damage in the colon, and its prevalence in the world is increasing. Nevertheless, the exact pathogenesis of UC is still unclear. Accumulating data have suggested that its pathogenesis is multifactorial, involving genetic predisposition, environmental factors, microbial dysbiosis, and dysregulated immune responses. Generally, UC is aroused by inappropriate immune activation based on the interaction of host and intestinal microbiota. The relationship between microbiota and host immune system in the pathogenesis of UC is complicated. However, increasing evidence indicates that the shift of microbiota composition can substantially influence intestinal immunity. In this review, we primarily focus on the delicate balance between microbiota and gut mucosal immunity during UC progression.
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Affiliation(s)
- Junfeng Zou
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China
| | - Chen Liu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China
| | - Shu Jiang
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China
| | - Dawei Qian
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China
| | - Jinao Duan
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China
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6
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Hajra D, Nair AV, Chakravortty D. An elegant nano-injection machinery for sabotaging the host: Role of Type III secretion system in virulence of different human and animal pathogenic bacteria. Phys Life Rev 2021; 38:25-54. [PMID: 34090822 DOI: 10.1016/j.plrev.2021.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 05/23/2021] [Indexed: 01/22/2023]
Abstract
Various Gram-negative bacteria possess a specialized membrane-bound protein secretion system known as the Type III secretion system (T3SS), which transports the bacterial effector proteins into the host cytosol thereby helping in bacterial pathogenesis. The T3SS has a special needle-like translocon that can sense the contact with the host cell membrane and translocate effectors. The export apparatus of T3SS recognizes these effector proteins bound to chaperones and translocates them into the host cell. Once in the host cell cytoplasm, these effector proteins result in modulation of the host system and promote bacterial localization and infection. Using molecular biology, bioinformatics, genetic techniques, electron microscopic studies, and mathematical modeling, the structure and function of the T3SS and the corresponding effector proteins in various bacteria have been studied. The strategies used by different human pathogenic bacteria to modulate the host system and thereby enhance their virulence mechanism using T3SS have also been well studied. Here we review the history, evolution, and general structure of the T3SS, highlighting the details of its comparison with the flagellar export machinery. Also, this article provides mechanistic details about the common role of T3SS in subversion and manipulation of host cellular processes. Additionally, this review describes specific T3SS apparatus and the role of their specific effectors in bacterial pathogenesis by considering several human and animal pathogenic bacteria.
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Affiliation(s)
- Dipasree Hajra
- Department of Microbiology & Cell Biology, Indian Institute of Science, India
| | - Abhilash Vijay Nair
- Department of Microbiology & Cell Biology, Indian Institute of Science, India
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7
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Riebisch AK, Mühlen S. Attaching and effacing pathogens: the effector ABC of immune subversion. Future Microbiol 2020; 15:945-958. [PMID: 32716209 DOI: 10.2217/fmb-2019-0274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The innate immune response resembles an essential barrier to bacterial infection. Many bacterial pathogens have, therefore, evolved mechanisms to evade from or subvert the host immune response in order to colonize, survive and multiply. The attaching and effacing pathogens enteropathogenic Escherichia coli, enterohaemorrhagic E. coli, Escherichia albertii and Citrobacter rodentium are Gram-negative extracellular gastrointestinal pathogens. They use a type III secretion system to inject effector proteins into the host cell to manipulate a variety of cellular processes. Over the last decade, considerable progress was made in identifying and characterizing the effector proteins of attaching and effacing pathogens that are involved in the inhibition of innate immune signaling pathways, in determining their host cell targets and elucidating the mechanisms they employ. Their functions will be reviewed here.
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Affiliation(s)
- Anna Katharina Riebisch
- Systems-Oriented Immunology & Inflammation Research, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.,Institute for Molecular & Clinical Immunology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany.,Department of Molecular Immunology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Sabrina Mühlen
- Institute for Infectiology, University of Münster, 48149 Münster, Germany.,German Center for Infection Research (DZIF), Associated Site University of Münster, 48149 Münster, Germany
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8
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He M, Chen X, Luo M, Ouyang L, Xie L, Huang Z, Liu A. Suppressor of cytokine signaling 1 inhibits the maturation of dendritic cells involving the nuclear factor kappa B signaling pathway in the glioma microenvironment. Clin Exp Immunol 2020; 202:47-59. [PMID: 32516488 DOI: 10.1111/cei.13476] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/22/2020] [Accepted: 05/24/2020] [Indexed: 12/30/2022] Open
Abstract
Recurrence and diffuse infiltration challenge traditional therapeutic strategies for malignant glioma. Immunotherapy appears to be a promising approach to obtain long-term survival. Dendritic cells (DCs), the most specialized and potent antigen-presenting cells (APCs), play an important part in initiating and amplifying both the innate and adaptive immune responses against cancer cells. However, cancer cells can escape from immune surveillance by inhibiting maturation of DCs. Until the present, molecular mechanisms of maturation inhibition of DCs in the tumor microenvironment (TME) have not been fully revealed. Our study showed that pretreatment with tumor-conditioned medium (TCM) collected from supernatant of primary glioma cells significantly suppressed the maturation of DCs. TCM pretreatment significantly changed the morphology of DCs, TCM decreased the expression levels of CD80, CD83, CD86 and interleukin (IL)-12p70, while it increased the expression levels of IL-10, transforming growth factor (TGF)-β and IL-6. RNA-Seq showed that TCM pretreatment significantly increased the gene expression level of suppressor of cytokine signaling 1 (SOCS1) in DCs. suppressor of cytokine signaling 1 (SOCS1) knock-down significantly antagonized the maturation inhibition of DCs by TCM, which was demonstrated by the restoration of maturation markers. TCM pretreatment also significantly suppressed T cell viability and T helper type 1 (Th1) response, and SOCS1 knock-down significantly antagonized this suppressive effect. Further, TCM pretreatment significantly suppressed p65 nuclear translocation and transcriptional activity in DCs, and SOCS1 knock-down significantly attenuated this suppressive effect. In conclusion, our research demonstrates that TCM up-regulate SOCS1 to suppress the maturation of DCs via the nuclear factor-kappa signaling pathway.
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Affiliation(s)
- M He
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - X Chen
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - M Luo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - L Ouyang
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - L Xie
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Z Huang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Neurosurgery, The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, China
| | - A Liu
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
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9
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Goddard PJ, Sanchez-Garrido J, Slater SL, Kalyan M, Ruano-Gallego D, Marchès O, Fernández LÁ, Frankel G, Shenoy AR. Enteropathogenic Escherichia coli Stimulates Effector-Driven Rapid Caspase-4 Activation in Human Macrophages. Cell Rep 2020; 27:1008-1017.e6. [PMID: 31018119 PMCID: PMC6486487 DOI: 10.1016/j.celrep.2019.03.100] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 02/20/2019] [Accepted: 03/27/2019] [Indexed: 12/20/2022] Open
Abstract
Microbial infections can stimulate the assembly of inflammasomes, which activate caspase-1. The gastrointestinal pathogen enteropathogenic Escherichia coli (EPEC) causes localized actin polymerization in host cells. Actin polymerization requires the binding of the bacterial adhesin intimin to Tir, which is delivered to host cells via a type 3 secretion system (T3SS). We show that EPEC induces T3SS-dependent rapid non-canonical NLRP3 inflammasome activation in human macrophages. Notably, caspase-4 activation by EPEC triggers pyroptosis and cytokine processing through the NLRP3-caspase-1 inflammasome. Mechanistically, caspase-4 activation requires the detection of LPS and EPEC-induced actin polymerization, either via Tir tyrosine phosphorylation and the phosphotyrosine-binding adaptor NCK or Tir and the NCK-mimicking effector TccP. An engineered E. coli K12 could reconstitute Tir-intimin signaling, which is necessary and sufficient for inflammasome activation, ruling out the involvement of other virulence factors. Our studies reveal a crosstalk between caspase-4 and caspase-1 that is cooperatively stimulated by LPS and effector-driven actin polymerization. EPEC bacteria expressing virulence genes induce rapid human macrophage pyroptosis Bacterial LPS sensing by caspase-4 activates NLRP3-caspase-1 inflammasomes Actin polymerization driven by Tir-intimin signaling promotes pyroptosis Caspase-1 mediates cytokine processing and gasdermin D cleavage, leading to pyroptosis
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Affiliation(s)
- Philippa J Goddard
- Department of Life Sciences, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK; Department of Medicine, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - Julia Sanchez-Garrido
- Department of Medicine, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - Sabrina L Slater
- Department of Life Sciences, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - Mohini Kalyan
- Department of Medicine, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - David Ruano-Gallego
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Olivier Marchès
- Department of Life Sciences, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - Luis Ángel Fernández
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Gad Frankel
- Department of Life Sciences, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - Avinash R Shenoy
- Department of Medicine, Medical Research Council Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK.
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10
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EspFu-Mediated Actin Assembly Enhances Enteropathogenic Escherichia coli Adherence and Activates Host Cell Inflammatory Signaling Pathways. mBio 2020; 11:mBio.00617-20. [PMID: 32291304 PMCID: PMC7157822 DOI: 10.1128/mbio.00617-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
EPEC is among the leading causes of diarrheal disease worldwide. The colonization of the gut mucosa by EPEC results in actin pedestal formation at the site of bacterial attachment. These pedestals are referred to as attaching and effacing (AE) lesions. Here, we exploit the different molecular mechanisms used by EPEC to induce AE lesions on epithelial cells, showing that the effector EspFu is associated with increased bacterial attachment and enhanced epithelial colonization compared to the Tir-Nck pathway. Moreover, we also showed that actin pedestal formation can counterbalance the anti-inflammatory activity induced by EPEC, especially when driven by EspFu. Collectively, our findings provide new insights into virulence mechanisms employed by EPEC to colonize epithelial cells, as well as the host response to this enteric pathogen. The translocation of effectors into the host cell through type 3 secretion systems (T3SS) is a sophisticated strategy employed by pathogenic bacteria to subvert host responses and facilitate colonization. Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) utilize the Tir and EspFu (also known as TccP) effectors to remodel the host cytoskeleton, culminating in the formation of attaching and effacing (AE) lesions on enterocytes. While some EPEC strains require tyrosine phosphorylation of Tir and recruitment of the host Nck to trigger actin polymerization, EHEC and certain EPEC strains, whose Tir is not phosphorylated, rely on the effector EspFu for efficient actin remodeling. Here, we investigated the role played by Tir-Nck and Tir-EspFu actin polymerization pathways during the infection of epithelial cells, as well as the host transcriptional response to the AE lesion formation induced by EPEC. We found that EspFu-mediated actin assembly promotes bacterial attachment and epithelial colonization more efficiently than Tir-Nck. Moreover, we showed that both actin polymerization mechanisms can activate inflammatory pathways and reverse the anti-inflammatory response induced by EPEC in epithelial cells. However, this activity is remarkably more evident in infections with EspFu-expressing EPEC strains. This study demonstrates the complex interactions between effector-mediated actin remodeling and inflammation. Different strains carry different combinations of these two effectors, highlighting the plasticity of pathogenic E. coli enteric infections.
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11
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Molecular Mechanisms That Define Redox Balance Function in Pathogen-Host Interactions-Is There a Role for Dietary Bioactive Polyphenols? Int J Mol Sci 2019; 20:ijms20246222. [PMID: 31835548 PMCID: PMC6940965 DOI: 10.3390/ijms20246222] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 01/01/2023] Open
Abstract
To ensure a functional immune system, the mammalian host must detect and respond to the presence of pathogenic bacteria during infection. This is accomplished in part by generating reactive oxygen species (ROS) that target invading bacteria; a process that is facilitated by NADPH oxidase upregulation. Thus, bacterial pathogens must overcome the oxidative burst produced by the host innate immune cells in order to survive and proliferate. In this way, pathogenic bacteria develop virulence, which is related to the affinity to secrete effector proteins against host ROS in order to facilitate microbial survival in the host cell. These effectors scavenge the host generated ROS directly, or alternatively, manipulate host cell signaling mechanisms designed to benefit pathogen survival. The redox-balance of the host is important for the regulation of cell signaling activities that include mitogen-activated protein kinase (MAPK), p21-activated kinase (PAK), phosphatidylinositol 3-kinase (PI3K)/Akt, and nuclear factor κB (NF-κB) pathways. An understanding of the function of pathogenic effectors to divert host cell signaling is important to ascertain the mechanisms underlying pathogen virulence and the eventual host–pathogen relationship. Herein, we examine the effectors produced by the microbial secretion system, placing emphasis on how they target molecular signaling mechanisms involved in a host immune response. Moreover, we discuss the potential impact of bioactive polyphenols in modulating these molecular interactions that will ultimately influence pathogen virulence.
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12
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Zhao Y, Uduman M, Siu JHY, Tull TJ, Sanderson JD, Wu YCB, Zhou JQ, Petrov N, Ellis R, Todd K, Chavele KM, Guesdon W, Vossenkamper A, Jassem W, D'Cruz DP, Fear DJ, John S, Scheel-Toellner D, Hopkins C, Moreno E, Woodman NL, Ciccarelli F, Heck S, Kleinstein SH, Bemark M, Spencer J. Spatiotemporal segregation of human marginal zone and memory B cell populations in lymphoid tissue. Nat Commun 2018; 9:3857. [PMID: 30242242 PMCID: PMC6155012 DOI: 10.1038/s41467-018-06089-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/17/2018] [Indexed: 01/19/2023] Open
Abstract
Human memory B cells and marginal zone (MZ) B cells share common features such as the expression of CD27 and somatic mutations in their IGHV and BCL6 genes, but the relationship between them is controversial. Here, we show phenotypic progression within lymphoid tissues as MZ B cells emerge from the mature naïve B cell pool via a precursor CD27-CD45RBMEM55+ population distant from memory cells. By imaging mass cytometry, we find that MZ B cells and memory B cells occupy different microanatomical niches in organised gut lymphoid tissues. Both populations disseminate widely between distant lymphoid tissues and blood, and both diversify their IGHV repertoire in gut germinal centres (GC), but nevertheless remain largely clonally separate. MZ B cells are therefore not developmentally contiguous with or analogous to classical memory B cells despite their shared ability to transit through GC, where somatic mutations are acquired.
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Affiliation(s)
- Yuan Zhao
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Mohamed Uduman
- Department of Pathology, Yale University School of Medicine, New Haven, CT, 06511, USA
| | | | - Thomas J Tull
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Jeremy D Sanderson
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Yu-Chang Bryan Wu
- Randall Division of Cell and Molecular Biophysics, King's College London, London, SE1 1UL, UK
| | - Julian Q Zhou
- Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, 06511, USA
| | - Nedyalko Petrov
- Biomedical Research Centre, Guy's and St. Thomas' NHS Trust, London, SE1 9RT, UK
| | - Richard Ellis
- Biomedical Research Centre, Guy's and St. Thomas' NHS Trust, London, SE1 9RT, UK
| | - Katrina Todd
- Biomedical Research Centre, Guy's and St. Thomas' NHS Trust, London, SE1 9RT, UK
| | - Konstantia-Maria Chavele
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - William Guesdon
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Anna Vossenkamper
- Barts & The London School of Medicine and Dentistry, Blizard Institute, Whitechapel, London, E1 2AT, UK
| | - Wayel Jassem
- Liver Transplant Unit, Institute of Liver Studies, King's College Hospital, Denmark Hill, London, SE5 9NT, UK
| | - David P D'Cruz
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - David J Fear
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Susan John
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Dagmar Scheel-Toellner
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Claire Hopkins
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Estefania Moreno
- Barts & The London School of Medicine and Dentistry, Blizard Institute, Whitechapel, London, E1 2AT, UK
| | - Natalie L Woodman
- School of Cancer Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Francesca Ciccarelli
- School of Cancer Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Susanne Heck
- Biomedical Research Centre, Guy's and St. Thomas' NHS Trust, London, SE1 9RT, UK
| | - Steven H Kleinstein
- Department of Pathology, Yale University School of Medicine, New Haven, CT, 06511, USA.
- Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, 06511, USA.
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, 06511, USA.
| | - Mats Bemark
- Mucosal Immunobiology and Vaccine Center (MIVAC), Department of Microbiology and Immunology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, SE 405 30, Gothenburg, Sweden.
| | - Jo Spencer
- School of Immunology and Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK.
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13
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Pinaud L, Sansonetti PJ, Phalipon A. Host Cell Targeting by Enteropathogenic Bacteria T3SS Effectors. Trends Microbiol 2018; 26:266-283. [DOI: 10.1016/j.tim.2018.01.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/29/2018] [Accepted: 01/29/2018] [Indexed: 12/23/2022]
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14
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Cooperative Immune Suppression by Escherichia coli and Shigella Effector Proteins. Infect Immun 2018; 86:IAI.00560-17. [PMID: 29339461 DOI: 10.1128/iai.00560-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The enteric attaching and effacing (A/E) pathogens enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) and the invasive pathogens enteroinvasive E. coli (EIEC) and Shigella encode type III secretion systems (T3SS) used to inject effector proteins into human host cells during infection. Among these are a group of effectors required for NF-κB-mediated host immune evasion. Recent studies have identified several effector proteins from A/E pathogens and EIEC/Shigella that are involved in suppression of NF-κB and have uncovered their cellular and molecular functions. A novel mechanism among these effectors from both groups of pathogens is to coordinate effector function during infection. This cooperativity among effector proteins explains how bacterial pathogens are able to effectively suppress innate immune defense mechanisms in response to diverse classes of immune receptor signaling complexes (RSCs) stimulated during infection.
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15
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Liu H, Xu W, Chang X, Qin T, Yin Y, Yang Q. 4,4'-diaponeurosporene, a C30 carotenoid, effectively activates dendritic cells via CD36 and NF-κB signaling in a ROS independent manner. Oncotarget 2018; 7:40978-40991. [PMID: 27276712 PMCID: PMC5173036 DOI: 10.18632/oncotarget.9800] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/28/2016] [Indexed: 12/14/2022] Open
Abstract
Carotenoids could be divided into C30 carotenoids and C40 carotenoids. The immune functions of C40 carotenoids had been extensively researched, while those of C30 carotenoids still remain unclear. In this study, the immune functions of a biosynthetic C30 carotenoid, 4,4'-diaponeurosporene (Dia), were identified on dendritic cells (DCs). DCs treated with 1 μM Dia for 24 h showed morphologic and phenotypic characteristics of mature state and had an increased production of IL-6, IL-10, IL-12p70 and TNFα, while β-carotene had a suppressive effect on DCs maturation. Moreover, Dia promoted antigen uptake of DCs in vitro and increased the quantity of antigen loaded DCs in mesenteric lymph nodes (MLN). Dia-treated DCs also had an enhanced ability to stimulate T cell proliferation and Th1 polarization. Further researches showed that Dia activated DCs via CD36 as well as ERK, JNK, and NF-κB signals in a reactive oxygen species (ROS) independent manner.
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Affiliation(s)
- Haofei Liu
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Wenwen Xu
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Xiaojing Chang
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Tao Qin
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Yinyan Yin
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Qian Yang
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
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16
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Sharma P, Guha S, Garg P, Roy S. Differential expression of antimicrobial peptides in corneal infection and regulation of antimicrobial peptides and reactive oxygen species by type III secretion system of Pseudomonas aeruginosa. Pathog Dis 2018; 76:4794940. [DOI: 10.1093/femspd/fty001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/06/2018] [Indexed: 11/14/2022] Open
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17
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Su XW, Lu G, Leung CK, Liu Q, Li Y, Tsang KS, Zhao SD, Chan DTM, Kung HF, Poon WS. miR-181d regulates human dendritic cell maturation through NF-κB pathway. Cell Prolif 2017; 50. [PMID: 28731516 DOI: 10.1111/cpr.12358] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 05/15/2017] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES MicroRNAs (miRNAs) are considered as the cellular regulators which post-transcriptionally modulate gene expression in diverse biological processes including cell development and immunity. In this study, we investigated functions of miR-181d in dendritic cells (DCs) maturation, and the underlying mechanisms were also explored. MATERIALS AND METHODS Here we did the miRNA screening in human DCs in response to lipopolysaccharides (LPS) by quantitative real-time PCR (qRT-PCR). The expressions of DCs maturation markers were measured after miRNA mimics transfections. The pharmacological inhibitors of signalling pathways were applied to examine miR-181d effect on DCs maturation by Western blot. Luciferase assay and mixed lymphocyte reaction (MLR) were also performed to reveal the target gene of miR-181d and test the viability of T cells treated with miR-181d transfected DCs. RESULTS Overexpression of miR-181d per se is sufficient to promote DCs maturation, and up-regulate CD80 and CD83 expressions without LPS. Besides, we showed that miR-181d activated NF-κB pathway and also promoted the expression of pro-inflammatory cytokine IL12 and TNF-α. Inhibition of NF-κB pathway suppressed DCs maturation. Luciferase reporter assay and target gene knockdown assay indicated that miR-181d targets regulator cylindromatosis (CYLD), a primary negative regulator of NF-κB pathway. MLR assay showed that miR-181d-transfected DCs could promote T-cell proliferation than iDCs in vitro. CONCLUSION Our study demonstrates that miR-181d is required for DCs maturation through the activation of NF-κB pathway by targeting CYLD.
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Affiliation(s)
- Xian Wei Su
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Gang Lu
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Kwan Leung
- Center for Reproductive Medicine, Shandong University, Jinan, China
| | - Qiang Liu
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Yi Li
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Kam Sze Tsang
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Shi Dou Zhao
- Center for Reproductive Medicine, Shandong University, Jinan, China
| | - Danny Tat Ming Chan
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.,Otto Wong Brain Tumour Centre, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Hsiang Fu Kung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Sang Poon
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.,Otto Wong Brain Tumour Centre, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
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18
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Niacin and Selenium Attenuate Sepsis-Induced Lung Injury by Up-Regulating Nuclear Factor Erythroid 2-Related Factor 2 Signaling. Crit Care Med 2017; 44:e370-82. [PMID: 26646455 DOI: 10.1097/ccm.0000000000001422] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVES To determine whether the combination therapy of niacin and selenium attenuates lung injury and improves survival during sepsis in rats and whether its benefits are associated with the activation of the glutathione redox cycle and up-regulation of nuclear factor erythroid 2-related factor 2. DESIGN Prospective laboratory study. SETTING University laboratory. SUBJECTS Human lung microvascular endothelial cells and male Sprague-Dawley rats (n = 291). INTERVENTION In lipopolysaccharide-exposed cells, the dose-related effects of niacin and selenium were assessed, and the therapeutic effects of the combination therapy of niacin (0.9 mM) and selenium (1.5 μM) were evaluated. The role of nuclear factor erythroid 2-related factor 2 was determined using nuclear factor erythroid 2-related factor 2 knockdown cells. In endotoxemic and cecal ligation and puncture with antibiotics rats, the therapeutic effects of the posttreatments of clinically relevant doses of niacin (360 mg/kg) and selenium (60 μg/kg) were evaluated. MEASUREMENTS AND MAIN RESULTS Combination therapy reduced the hydrogen peroxide level via the synergistic activation of the glutathione redox cycle, which involves niacin-induced increases in glutathione reductase activity, and reduced the glutathione level and a selenium-induced increase in glutathione peroxidase activity. Combination therapy contributed to the up-regulation of nuclear factor erythroid 2-related factor 2, enhancement of glutathione synthesis, and down-regulation of nuclear factor κB signaling, but nuclear factor erythroid 2-related factor 2 knockdown inhibited the enhancement of glutathione synthesis and down-regulation of the nuclear factor κB pathway. The therapeutic effects of combination therapy on endotoxemic rats were consistent with those on lipopolysaccharide-exposed cells. In addition, the posttreatment of combination therapy attenuated lung injury and improved survival in endotoxemic and cecal ligation and puncture with antibiotics rats. However, individual therapies of niacin or selenium failed to achieve these benefits. CONCLUSIONS The combination therapy of niacin and selenium attenuated lung injury and improved survival during sepsis. Its therapeutic benefits were associated with the synergistic activation of the glutathione redox cycle, reduction of hydrogen peroxide level, and up-regulation of nuclear factor erythroid 2-related factor 2.
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19
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Nirujogi RS, Muthusamy B, Kim MS, Sathe GJ, Lakshmi PTV, Kovbasnjuk ON, Prasad TSK, Wade M, Jabbour RE. Secretome analysis of diarrhea-inducing strains of Escherichia coli. Proteomics 2017; 17. [PMID: 28070933 DOI: 10.1002/pmic.201600299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 12/19/2016] [Accepted: 01/05/2017] [Indexed: 01/05/2023]
Abstract
Secreted proteins constitute a major part of virulence factors that are responsible for pathogenesis caused by Gram-negative bacteria. Enterohemorrhagic Escherichia coli, O157:H7, is the major pathogen often causing outbreaks. However, studies have reported that the significant outbreaks caused by non-O157:H7 E. coli strains, also known as "Big-Six" serogroup strains, are increasing. There is no systematic study describing differential secreted proteins from these non-O157:H7 E. coli strains. In this study, we carried out MS-based differential secretome analysis using tandem mass tags labeling strategy of non-O157:H7 E. coli strains, O103, O111, O121, O145, O26, and O45. We identified 1241 proteins, of which 565 proteins were predicted to be secreted. We also found that 68 proteins were enriched in type III secretion system and several of them were differentially expressed across the strains. Additionally, we identified several strain-specific secreted proteins that could be used for developing potential markers for the identification and strain-level differentiation. To our knowledge, this study is the first comparative proteomic study on secretome of E. coli Big-Six serogroup and the several of these strain-specific secreted proteins can be further studied to develop potential markers for identification and strain-level differentiation. Moreover, the results of this study can be utilized in several applications, including food safety, diagnostics of E. coli outbreaks, and detection and identification of bio threats in biodefense.
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Affiliation(s)
- Raja Sekhar Nirujogi
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Centre for Bioinformatics, Pondicherry University, Puducherry, India.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Min-Sik Kim
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, South Korea
| | - Gajanan J Sathe
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Manipal University, Madhav Nagar, Manipal, India
| | - P T V Lakshmi
- Centre for Bioinformatics, Pondicherry University, Puducherry, India
| | - Olga N Kovbasnjuk
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - T S Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Centre for Bioinformatics, Pondicherry University, Puducherry, India.,Manipal University, Madhav Nagar, Manipal, India.,NIMHANS-IOB Proteomics and Bioinformatics Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neuro Sciences, Bangalore, India.,YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, India
| | - Mary Wade
- Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Rabih E Jabbour
- Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
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20
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Zhuang X, Chen Z, He C, Wang L, Zhou R, Yan D, Ge B. Modulation of host signaling in the inflammatory response by enteropathogenic Escherichia coli virulence proteins. Cell Mol Immunol 2017; 14:237-244. [PMID: 27796284 PMCID: PMC5360883 DOI: 10.1038/cmi.2016.52] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 07/24/2016] [Accepted: 07/25/2016] [Indexed: 12/27/2022] Open
Abstract
To successfully infect host cells and evade the host immune response, a type III secretion system (T3SS) is commonly used by enteric bacterial pathogens such as enteropathogenic Escherichia coli (EPEC). Recent findings have revealed that various effectors are injected into host cells through the T3SS and exert an inhibitory effect on inflammatory signaling pathways, subverting the immune responses to these pathogens. Here we review recent studies aimed at addressing the modulation of several important inflammatory signaling pathways modulated by EPEC effector proteins, such as the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, which provides insight into the unfinished work in this unexplored field and helps to identify novel positions in inflammatory signaling networks for EPEC effectors.Cellular & Molecular Immunology advance online publication, 31 October 2016; doi:10.1038/cmi.2016.52.
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Affiliation(s)
- Xiaonan Zhuang
- Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Zijuan Chen
- Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Chenxi He
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai 200092, China
| | - Lin Wang
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai 200092, China
| | - Ruixue Zhou
- Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Dapeng Yan
- Department of Immunology and Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Baoxue Ge
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai 200092, China
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200092, China
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21
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Sanchez-Villamil J, Tapia-Pastrana G, Navarro-Garcia F. Pathogenic Lifestyles of E. coli Pathotypes in a Standardized Epithelial Cell Model Influence Inflammatory Signaling Pathways and Cytokines Secretion. Front Cell Infect Microbiol 2016; 6:120. [PMID: 27774437 PMCID: PMC5054702 DOI: 10.3389/fcimb.2016.00120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/21/2016] [Indexed: 12/21/2022] Open
Abstract
Inflammatory response is key for the host defense against diarrheagenic Escherichia coli and contributes to the pathogenesis of the disease but there is not a comparative study among different diarrheagenic pathotypes. We analyzed the inflammatory response induced by five diarrheagenic pathotypes in a HT-29 cell infection model. The model was unified to reproduce the pathogenesis of each pathotype. To compare the inflammatory responses we evaluated: (i) nuclear NF-κB and ERK1/2 translocation by confocal microscopy; (ii) kinetics of activation by each pathway detecting p65 and ERK1/2 phosphorylation by Western blotting; (iii) pathways modulation through bacterial infections with or without co-stimulation with TNF-α or EGF; (iv) cytokine profile induced by each pathotype with and without inhibitors of each pathway. EHEC but mainly EPEC inhibited translocation and activation of p65 and ERK1/2 pathways, as well as cytokines secretion; inhibition of p65 and ERK1/2 phosphorylation prevailed in the presence of TNF-α and EGF, respectively. Intracellular strains, EIEC/Shigella flexneri, caused a strong translocation, activation, and cytokines secretion but they could not inhibit TNF-α and EGF stimulation. ETEC and mainly EAEC caused a moderate translocation, but a differential activation, and high cytokines secretion; interestingly TNF-α and EGF stimulation did no modify p65 and ERK1/2 activation. The use of inhibitors of NF-κB and/or ERK1/2 showed that NF-κB is crucial for cytokine induction by the different pathotypes; only partially depended on ERK1/2 activation. Thus, in spite of their differences, the pathotypes can also be divided in three groups according to their inflammatory response as those (i) that inject effectors to cause A/E lesion, which are able to inhibit NF-κB and ERK1/2 pathways, and cytokine secretion; (ii) with fimbrial adherence and toxin secretion with a moderate inhibition of both pathways but high cytokines secretion through autocrine cytokine regulation; and (iii) the intracellular bacteria that induce the highest pathways activation and cytokines secretion by using different activation mechanisms. This study provides a comprehensive analysis of how the different pathogenesis schemes of E. coli pathotypes manipulate inflammatory signaling pathways, which leads to a specific proinflammatory cytokine secretion in a cell model infection that reproduce the hallmarks of infection of each pathotype.
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Affiliation(s)
- Javier Sanchez-Villamil
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico
| | - Gabriela Tapia-Pastrana
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico
| | - Fernando Navarro-Garcia
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico
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22
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Wang S, Liu X, Xu X, Yang D, Wang D, Han X, Shi Y, Tian M, Ding C, Peng D, Yu S. Escherichia coli Type III Secretion System 2 ATPase EivC Is Involved in the Motility and Virulence of Avian Pathogenic Escherichia coli. Front Microbiol 2016; 7:1387. [PMID: 27630634 PMCID: PMC5005338 DOI: 10.3389/fmicb.2016.01387] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/22/2016] [Indexed: 01/13/2023] Open
Abstract
Type III secretion systems (T3SSs) are crucial for bacterial infections because they deliver effector proteins into host cells. The Escherichia coli type III secretion system 2 (ETT2) is present in the majority of E. coli strains, and although it is degenerate, ETT2 regulates bacterial virulence. An ATPase is essential for T3SS secretion, but the function of the ETT2 ATPase has not been demonstrated. Here, we show that EivC is homologous to the β subunit of F0F1 ATPases and it possesses ATPase activity. To investigate the effects of ETT2 ATPase EivC on the phenotype and virulence of avian pathogenic Escherichia coli (APEC), eivC mutant and complemented strains were constructed and characterized. Inactivation of eivC led to impaired flagella production and augmented fimbriae on the bacterial surface, and, consequently, reduced bacterial motility. In addition, the eivC mutant strain exhibited attenuated virulence in ducks, diminished serum resistance, reduced survival in macrophage cells and in ducks, upregulated fimbrial gene expression, and downregulated flagellar and virulence gene expression. The expression of the inflammatory cytokines interleukin (IL)-1β and IL-8 were increased in HD-11 macrophages infected with the eivC mutant strain, compared with the wild-type strain. These virulence-related phenotypes were restored by genetic complementation. These findings demonstrate that ETT2 ATPase EivC is involved in the motility and pathogenicity of APEC.
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Affiliation(s)
- Shaohui Wang
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Xin Liu
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural SciencesShanghai, China; College of Veterinary Medicine, Yangzhou UniversityYangzhou, China
| | - Xuan Xu
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Denghui Yang
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Dong Wang
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Xiangan Han
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Yonghong Shi
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Chan Ding
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
| | - Daxin Peng
- College of Veterinary Medicine, Yangzhou University Yangzhou, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute - Chinese Academy of Agricultural Sciences Shanghai, China
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23
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Yen H, Karino M, Tobe T. Modulation of the Inflammasome Signaling Pathway by Enteropathogenic and Enterohemorrhagic Escherichia coli. Front Cell Infect Microbiol 2016; 6:89. [PMID: 27617233 PMCID: PMC4999430 DOI: 10.3389/fcimb.2016.00089] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 08/11/2016] [Indexed: 01/07/2023] Open
Abstract
Innate immunity is an essential component in the protection of a host against pathogens. Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively) are known to modulate the innate immune responses of infected cells. The interference is dependent on their type III secretion system (T3SS) and T3SS-dependent effector proteins. Furthermore, these cytosolically injected effectors have been demonstrated to engage multiple immune signaling pathways, including the IFN/STAT, MAPK, NF-κB, and inflammasome pathways. In this review, recent work describing the interaction between EPEC/EHEC and the inflammasome pathway will be discussed.
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Affiliation(s)
- Hilo Yen
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University Osaka, Japan
| | - Masaki Karino
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University Osaka, Japan
| | - Toru Tobe
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University Osaka, Japan
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24
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The Locus of Enterocyte Effacement and Associated Virulence Factors of Enterohemorrhagic Escherichia coli. Microbiol Spectr 2016; 2:EHEC-0007-2013. [PMID: 26104209 DOI: 10.1128/microbiolspec.ehec-0007-2013] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A subset of Shiga toxin-producing Escherichia coli strains, termed enterohemorrhagic E. coli (EHEC), is defined in part by the ability to produce attaching and effacing (A/E) lesions on intestinal epithelia. Such lesions are characterized by intimate bacterial attachment to the apical surface of enterocytes, cytoskeletal rearrangements beneath adherent bacteria, and destruction of proximal microvilli. A/E lesion formation requires the locus of enterocyte effacement (LEE), which encodes a Type III secretion system that injects bacterial proteins into host cells. The translocated proteins, termed effectors, subvert a plethora of cellular pathways to the benefit of the pathogen, for example, by recruiting cytoskeletal proteins, disrupting epithelial barrier integrity, and interfering with the induction of inflammation, phagocytosis, and apoptosis. The LEE and selected effectors play pivotal roles in intestinal persistence and virulence of EHEC, and it is becoming clear that effectors may act in redundant, synergistic, and antagonistic ways during infection. Vaccines that target the function of the Type III secretion system limit colonization of reservoir hosts by EHEC and may thus aid control of zoonotic infections. Here we review the features and functions of the LEE-encoded Type III secretion system and associated effectors of E. coli O157:H7 and other Shiga toxin-producing E. coli strains.
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25
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Luo J, Hu J, Zhang Y, Hu Q, Li S. Hijacking of death receptor signaling by bacterial pathogen effectors. Apoptosis 2015; 20:216-23. [PMID: 25528554 DOI: 10.1007/s10495-014-1068-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Death receptors such as Tumor necrosis factor receptor 1, FAS and TNF-associated apoptosis-inducing ligand-R1/2 play a major role in counteracting with bacterial pathogen infection through regulation of inflammation and programmed cell death. The highly regulated death receptor signaling is frequently targeted by gram-negative bacterial pathogens such as Salmonella, Shigella, enteropathogenic Escherichia coli and enterohamorrhagic Escherichia coli, which harbor a conserved type III secretion system that delivers a repertoire of effector proteins to manipulate host signal transductions for their own benefit. This review focuses on how bacterial gut pathogens hijack death receptor signaling to inhibit host NF-κB and programmed cell death pathways.
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Affiliation(s)
- Jie Luo
- Taihe Hospital, Hubei University of Medicine, #32 Renmin South Rd, Shiyan, 442000, Hubei, China
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Yen H, Sugimoto N, Tobe T. Enteropathogenic Escherichia coli Uses NleA to Inhibit NLRP3 Inflammasome Activation. PLoS Pathog 2015; 11:e1005121. [PMID: 26332984 PMCID: PMC4557958 DOI: 10.1371/journal.ppat.1005121] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/31/2015] [Indexed: 11/18/2022] Open
Abstract
Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are related strains capable of inducing severe gastrointestinal disease. For optimal infection, these pathogens actively modulate cellular functions through the deployment of effector proteins in a type three secretion system (T3SS)-dependent manner. In response to enteric pathogen invasion, the Nod-like receptor pyrin domain containing (NLRP) inflammasome has been increasingly recognized as an important cytoplasmic sensor against microbial infection by activating caspase-1 and releasing IL-1β. EPEC and EHEC are known to elicit inflammasome activation in macrophages and epithelial cells; however, whether the pathogens actively counteract such innate immune responses is unknown. Using a series of compound effector-gene deletion strains of EPEC, we screened and identified NleA, which could subdue host IL-1β secretion. It was found that the reduction is not because of blocked NF-κB activity; instead, the reduction results from inhibited caspase-1 activation by NleA. Immunostaining of human macrophage-like cells following infection revealed limited formation of inflammasome foci with constituents of total caspase-1, ASC and NLRP3 in the presence of NleA. Pulldown of PMA-induced differentiated THP-1 lysate with purified MBP-NleA reveals that NLRP3 is a target of NleA. The interaction was verified by an immunoprecipitation assay and direct interaction assay in which purified MBP-NleA and GST-NLRP3 were used. We further showed that the effector interacts with regions of NLRP3 containing the PYD and LRR domains. Additionally, NleA was found to associate with non-ubiquitinated and ubiquitinated NLRP3 and to interrupt de-ubiquitination of NLRP3, which is a required process for inflammasome activation. Cumulatively, our findings provide the first example of EPEC-mediated suppression of inflammasome activity in which NieA plays a novel role in controlling the host immune response through targeting of NLRP3. Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) cause severe intestinal dysfunction, including watery diarrhea or severe bloody diarrhea, and acute kidney failure (hemolytic uremic syndrome). Transmitted through ingestion of contaminated food, these pathogens colonize and disrupt the linings of intestinal epithelial cells. EPEC and EHEC interrupt many cellular functions, including the inflammation response, to increase their chances of proliferation and survival in the intestine. Upon detection of the invasion, epithelial cells and immune cells secrete inflammatory cytokines to further boost the immune response for efficient clearance of the pathogens. IL-1β is an important inflammatory cytokine, and its secretion is regulated by a multimeric protein complex, termed the inflammasome, in host cells. In this study, we discovered that EPEC injects a bacterial effector protein, NleA, to inhibit the secretion of IL-1β. Exploring the potential mechanisms, we found that NleA does so by directly associating with NLRP3 (Nod-Like Receptor 3), one of the three basic components of the inflammasome, and that the presence of NleA interrupts the de-ubiquitination of NLRP3, which is a prerequisite for the assembly of the inflammasome. As a result, NleA reduces the formation of the NLRP3 inflammasome and negatively regulates the secretion of IL-1β.
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Affiliation(s)
- Hilo Yen
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Nakaba Sugimoto
- Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Toru Tobe
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University, Osaka, Japan
- * E-mail:
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Sanchez-Villamil J, Navarro-Garcia F. Role of virulence factors on host inflammatory response induced by diarrheagenic Escherichia coli pathotypes. Future Microbiol 2015; 10:1009-33. [DOI: 10.2217/fmb.15.17] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
ABSTRACT Pathogens are able to breach the intestinal barrier, and different bacterial species can display different abilities to colonize hosts and induce inflammation. Inflammatory response studies induced by enteropathogens as Escherichia coli are interesting since it has acquired diverse genetic mobile elements, leading to different E. coli pathotypes. Diarrheagenic E. coli secrete toxins, effectors and virulence factors that exploit the host cell functions to facilitate the bacterial colonization. Many bacterial proteins are delivered to the host cell for subverting the inflammatory response. Hereby, we have highlighted the specific processes used by E. coli pathotypes, by that subvert the inflammatory pathways. These mechanisms include an arrangement of pro- and anti-inflammatory responses to favor the appropriate environmental niche for the bacterial survival and growth.
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Affiliation(s)
- Javier Sanchez-Villamil
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Ap. Postal 14–740, 07000, México DF, Mexico
| | - Fernando Navarro-Garcia
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Ap. Postal 14–740, 07000, México DF, Mexico
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Bermudez-Brito M, Muñoz-Quezada S, Gómez-Llorente C, Matencio E, Romero F, Gil A. Lactobacillus paracasei CNCM I-4034 and its culture supernatant modulate Salmonella-induced inflammation in a novel transwell co-culture of human intestinal-like dendritic and Caco-2 cells. BMC Microbiol 2015; 15:79. [PMID: 25887178 PMCID: PMC5353866 DOI: 10.1186/s12866-015-0408-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/11/2015] [Indexed: 12/31/2022] Open
Abstract
Background The action of probiotics has been studied in vitro in cells isolated from both mice and humans, particularly enterocytes (IECs), dendritic cells (DCs) and co-cultures of peripheral DCs and IECs. Peripheral DCs and murine DCs differ from human gut DCs, and to date there are no data on the action of any probiotic on co-cultured human IECs and human intestinal DCs. To address this issue, a novel transwell model was used. Human IECs (Caco-2 cells) grown in the upper chamber of transwell filters were co-cultured with intestinal-like human DCs grown in the basolateral compartment of the transwells. The system was apically exposed for 4 h to live probiotic L. paracasei CNCM I-4034 obtained from the faeces of breastfed infants or to its cell-free culture supernatant (CFS) and challenged with Salmonella typhi. The secretion of pro- and anti-inflammatory cytokines in the basolateral compartment was determined by immunoassay, and the DC expression pattern of 20 TLR signaling pathway genes was analysed by PCR array. Results The presence of the live probiotic alone significantly increased IL-1β, IL-6, IL-8, TGF-β2, RANTES and IP-10 levels and decreased IL-12p40, IL-10, TGF- β1 and MIP-1α levels. This release was correlated with a significant increase in the expression of almost all TLR signaling genes. By contrast, incubation of the co-culture with CFS increased IL-1β, IL-6, TGF-β2 and IP-10 production only when Salmonella was present. This induction was correlated with an overall decrease in the expression of all TLR genes except TLR9, which was strongly up-regulated. Conclusions The data presented here clearly indicate that L. paracasei CNCM I-4034 significantly increases the release of pro-inflammatory cytokines, enhances TLR signaling pathway activation and stimulates rather than suppresses the innate immune system. Furthermore, our findings provide evidence that the effects of probiotics in the presence of IECs and DCs differ from the effects of probiotics on cultures of each cell type alone, as reported by us earlier. Thus, co-culture systems such as the one described here are needed to characterise the effects of probiotics in vitro, highlighting the potential utility of such co-cultures as a model system. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0408-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Miriam Bermudez-Brito
- Institute of Nutrition and Food Technology "José Mataix", Department of Biochemistry and Molecular Biology II, University of Granada, Biomedical Research Center, Avenida del Conocimiento s/n, 18100 Armilla, Granada, Spain
| | - Sergio Muñoz-Quezada
- Institute of Nutrition and Food Technology "José Mataix", Department of Biochemistry and Molecular Biology II, University of Granada, Biomedical Research Center, Avenida del Conocimiento s/n, 18100 Armilla, Granada, Spain
| | - Carolina Gómez-Llorente
- Institute of Nutrition and Food Technology "José Mataix", Department of Biochemistry and Molecular Biology II, University of Granada, Biomedical Research Center, Avenida del Conocimiento s/n, 18100 Armilla, Granada, Spain
| | - Esther Matencio
- Hero Global Technology Center, Hero Spain, S.A., 30820, Alcantarilla, Murcia, Spain
| | - Fernando Romero
- Hero Global Technology Center, Hero Spain, S.A., 30820, Alcantarilla, Murcia, Spain
| | - Angel Gil
- Institute of Nutrition and Food Technology "José Mataix", Department of Biochemistry and Molecular Biology II, University of Granada, Biomedical Research Center, Avenida del Conocimiento s/n, 18100 Armilla, Granada, Spain.
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Hodgson A, Wier EM, Fu K, Sun X, Yu H, Zheng W, Sham HP, Johnson K, Bailey S, Vallance BA, Wan F. Metalloprotease NleC suppresses host NF-κB/inflammatory responses by cleaving p65 and interfering with the p65/RPS3 interaction. PLoS Pathog 2015; 11:e1004705. [PMID: 25756944 PMCID: PMC4355070 DOI: 10.1371/journal.ppat.1004705] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/26/2015] [Indexed: 11/18/2022] Open
Abstract
Attaching/Effacing (A/E) pathogens including enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC) and the rodent equivalent Citrobacter rodentium are important causative agents of foodborne diseases. Upon infection, a myriad of virulence proteins (effectors) encoded by A/E pathogens are injected through their conserved type III secretion systems (T3SS) into host cells where they interfere with cell signaling cascades, in particular the nuclear factor kappaB (NF-κB) signaling pathway that orchestrates both innate and adaptive immune responses for host defense. Among the T3SS-secreted non-LEE-encoded (Nle) effectors, NleC, a metalloprotease, has been recently elucidated to modulate host NF-κB signaling by cleaving NF-κB Rel subunits. However, it remains elusive how NleC recognizes NF-κB Rel subunits and how the NleC-mediated cleavage impacts on host immune responses in infected cells and animals. In this study, we show that NleC specifically targets p65/RelA through an interaction with a unique N-terminal sequence in p65. NleC cleaves p65 in intestinal epithelial cells, albeit a small percentage of the molecule, to generate the p65¹⁻³⁸ fragment during C. rodentium infection in cultured cells. Moreover, the NleC-mediated p65 cleavage substantially affects the expression of a subset of NF-κB target genes encoding proinflammatory cytokines/chemokines, immune cell infiltration in the colon, and tissue injury in C. rodentium-infected mice. Mechanistically, the NleC cleavage-generated p65¹⁻³⁸ fragment interferes with the interaction between p65 and ribosomal protein S3 (RPS3), a 'specifier' subunit of NF-κB that confers a subset of proinflammatory gene transcription, which amplifies the effect of cleaving only a small percentage of p65 to modulate NF-κB-mediated gene expression. Thus, our results reveal a novel mechanism for A/E pathogens to specifically block NF-κB signaling and inflammatory responses by cleaving a small percentage of p65 and targeting the p65/RPS3 interaction in host cells, thus providing novel insights into the pathogenic mechanisms of foodborne diseases.
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Affiliation(s)
- Andrea Hodgson
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Eric M. Wier
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Kai Fu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Xin Sun
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Hongbing Yu
- Division of Gastroenterology, Department of Pediatrics, BC’s Children’s Hospital and Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Wenxin Zheng
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Ho Pan Sham
- Division of Gastroenterology, Department of Pediatrics, BC’s Children’s Hospital and Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Kaitlin Johnson
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Scott Bailey
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Bruce A. Vallance
- Division of Gastroenterology, Department of Pediatrics, BC’s Children’s Hospital and Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Fengyi Wan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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30
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Santos AS, Finlay BB. Bringing down the host: enteropathogenic and enterohaemorrhagic Escherichia coli effector-mediated subversion of host innate immune pathways. Cell Microbiol 2015; 17:318-32. [PMID: 25588886 DOI: 10.1111/cmi.12412] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/17/2014] [Accepted: 12/22/2014] [Indexed: 12/14/2022]
Abstract
Enteric bacterial pathogens commonly use a type III secretion system (T3SS) to successfully infect intestinal epithelial cells and survive and proliferate in the host. Enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC; EHEC) colonize the human intestinal mucosa, form characteristic histological lesions on the infected epithelium and require the T3SS for full virulence. T3SS effectors injected into host cells subvert cellular pathways to execute a variety of functions within infected host cells. The EPEC and EHEC effectors that subvert innate immune pathways--specifically those involved in phagocytosis, host cell survival, apoptotic cell death and inflammatory signalling--are all required to cause disease. These processes are reviewed within, with a focus on recent work that has provided insights into the functions and host cell targets of these effectors.
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Affiliation(s)
- Andrew S Santos
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada; Michael Smith Laboratories, The University of British Columbia, Vancouver, BC, Canada
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31
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Dolores JS, Agarwal S, Egerer M, Satchell KJF. Vibrio cholerae MARTX toxin heterologous translocation of beta-lactamase and roles of individual effector domains on cytoskeleton dynamics. Mol Microbiol 2015; 95:590-604. [PMID: 25427654 DOI: 10.1111/mmi.12879] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 12/17/2022]
Abstract
The Vibrio cholerae MARTXVc toxin delivers three effector domains to eukaryotic cells. To study toxin delivery and function of individual domains, the rtxA gene was modified to encode toxin with an in-frame beta-lactamase (Bla) fusion. The hybrid RtxA::Bla toxin was Type I secreted from bacteria; and then Bla was translocated into eukaryotic cells and delivered by autoprocessing, demonstrating that the MARTXVc toxin is capable of heterologous protein transfer. Strains that produce hybrid RtxA::Bla toxins that carry one effector domain in addition to Bla were found to more efficiently translocate Bla. In cell biological assays, the actin cross-linking domain (ACD) and Rho-inactivation domain (RID) are found to cross-link actin and inactivate RhoA, respectively, when other effector domains are absent, with toxin autoprocessing required for high efficiency. The previously unstudied alpha-beta hydrolase domain (ABH) is shown here to activate CDC42, although the effect is ameliorated when RID is also present. Despite all effector domains acting on cytoskeleton assembly, the ACD was sufficient to rapidly inhibit macrophage phagocytosis. Both the ACD and RID independently disrupted polarized epithelial tight junction integrity. The sufficiency of ACD but strong selection for retention of RID and ABH suggests these two domains may primarily function by modulating cell signaling.
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Affiliation(s)
- Jazel S Dolores
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
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32
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Pearson JS, Zhang Y, Newton HJ, Hartland EL. Post-modern pathogens: surprising activities of translocated effectors from E. coli and Legionella. Curr Opin Microbiol 2014; 23:73-9. [PMID: 25461576 DOI: 10.1016/j.mib.2014.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 11/16/2022]
Abstract
Many bacterial pathogens have the ability to manipulate cellular processes and interfere with host cell function through the translocation of bacterial 'effector' proteins. Dedicated protein secretion machines from Gram-negative pathogens, including type III, type IV and type VI secretion systems, inject virulence proteins into infected cells, altering normal cell physiology, including cell structure, metabolism, trafficking and signalling. While effectors were once thought to exert an effect simply by their localization and binding to host cell proteins, increasingly effectors are being recognised as enzymes, in some cases mediating highly novel post-translational modifications on host proteins. Here we highlight some of the more unusual activities of translocated effectors from enteropathogenic Escherichia coli and Legionella pneumophila.
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Affiliation(s)
- Jaclyn S Pearson
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Victoria 3000, Australia
| | - Ying Zhang
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Victoria 3000, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Victoria 3000, Australia
| | - Elizabeth L Hartland
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Victoria 3000, Australia.
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33
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Zhou Y, Zhu Y. Diversity of bacterial manipulation of the host ubiquitin pathways. Cell Microbiol 2014; 17:26-34. [PMID: 25339545 DOI: 10.1111/cmi.12384] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 09/29/2014] [Accepted: 10/07/2014] [Indexed: 12/17/2022]
Abstract
Ubiquitination is generally considered as a eukaryotic protein modification, which is catalysed by a three-enzyme cascade and is reversed by deubiquitinating enzymes. Ubiquitination directs protein degradation and regulates cell signalling, thereby plays key roles in many cellular processes including immune response, vesicle trafficking and cell cycle. Bacterial pathogens inject a series of virulent proteins, named effectors, into the host cells. Increasing evidence suggests that many effectors hijack the host ubiquitin pathways to benefit bacterial infection. This review summarizes the known functions and mechanisms of effectors from human bacterial pathogens including enteropathogenic Escherichia coli, Salmonella, Shigella, Chlamydia and Legionella, highlighting the diversity in their mechanisms for manipulating the host ubiquitin pathways. Many effectors adopt the molecular mimicry strategy to harbour similar structures or functional motifs with those of the host E3 ligases and deubiquitinases. On the other hand, a few of effectors evolve novel structures or new enzymatic activities to modulate various steps of the host ubiquitin pathways. The diversity in the mechanisms enhances the efficient exploitation of the host ubiquitination signalling by bacteria.
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Affiliation(s)
- Yan Zhou
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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34
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Yao Q, Zhang L, Wan X, Chen J, Hu L, Ding X, Li L, Karar J, Peng H, Chen S, Huang N, Rauscher FJ, Shao F. Structure and specificity of the bacterial cysteine methyltransferase effector NleE suggests a novel substrate in human DNA repair pathway. PLoS Pathog 2014; 10:e1004522. [PMID: 25412445 PMCID: PMC4239114 DOI: 10.1371/journal.ppat.1004522] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 10/15/2014] [Indexed: 11/18/2022] Open
Abstract
Enteropathogenic E. coli (EPEC) and related enterobacteria rely on a type III secretion system (T3SS) effector NleE to block host NF-κB signaling. NleE is a first in class, novel S-adenosyl-L-methionine (SAM)-dependent methyltransferase that methylates a zinc-coordinating cysteine in the Npl4-like Zinc Finger (NZF) domains in TAB2/3 adaptors in the NF-κB pathway, but its mechanism of action and other human substrates are unknown. Here we solve crystal structure of NleE-SAM complex, which reveals a methyltransferase fold different from those of known ones. The SAM, cradled snugly at the bottom of a deep and narrow cavity, adopts a unique conformation ready for nucleophilic attack by the methyl acceptor. The substrate NZF domain can be well docked into the cavity, and molecular dynamic simulation indicates that Cys673 in TAB2-NZF is spatially and energetically favorable for attacking the SAM. We further identify a new NleE substrate, ZRANB3, that functions in PCNA binding and remodeling of stalled replication forks at the DNA damage sites. Specific inactivation of the NZF domain in ZRANB3 by NleE offers a unique opportunity to suggest that ZRANB3-NZF domain functions in DNA repair processes other than ZRANB3 recruitment to DNA damage sites. Our analyses suggest a novel and unexpected link between EPEC infection, virulence proteins and genome integrity. Pathogens often manipulate host functions by posttranslational modifications such as ubiquitination and methylation. The NF-κB pathway is most critical for immune defense against infection, thereby frequently targeted by bacterial virulence factors. NleE, a virulence effector from EPEC, is a SAM-dependent methyltransferase that modifies a zinc-finger cysteine in TAB2/3 in the NF-κB pathway. NleE is not homologous to any known methyltransferases. We present the crystal structure of SAM-bound NleE that shows a novel methyltransferase fold with a unique SAM-binding mode. Computational docking and molecular dynamics simulation illustrate a structural and chemical mechanism underlying NleE recognition of the NZF and catalyzing site-specific cysteine methylation. Subsequent substrate specificity analyses identify an N-terminal region in TAB3 required for efficient NleE recognition as well as another NZF protein ZRANB3 being a new substrate of NleE. NleE-catalyzed cysteine methylation also disrupts the ubiquitin chain-binding of ZRANB3-NZF domain, providing new insights into ZRANB3-NZF functioning in DNA damage repair. These results reinforce the idea of harnessing bacterial effectors as a tool for dissecting eukaryotic functions.
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Affiliation(s)
- Qing Yao
- National Institute of Biological Sciences, Beijing, China
| | - Li Zhang
- National Institute of Biological Sciences, Beijing, China
| | - Xiaobo Wan
- National Institute of Biological Sciences, Beijing, China
| | - Jing Chen
- National Institute of Biological Sciences, Beijing, China
| | - Liyan Hu
- National Institute of Biological Sciences, Beijing, China
| | - Xiaojun Ding
- National Institute of Biological Sciences, Beijing, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing, China
| | - Jayashree Karar
- The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Hongzhuang Peng
- The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - She Chen
- National Institute of Biological Sciences, Beijing, China
| | - Niu Huang
- National Institute of Biological Sciences, Beijing, China
| | - Frank J. Rauscher
- The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Feng Shao
- National Institute of Biological Sciences, Beijing, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- National Institute of Biological Sciences, Beijing, Collaborative Innovation Center for Cancer Medicine, Beijing, China
- * E-mail:
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35
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The type III secretion effector NleF of enteropathogenic Escherichia coli activates NF-κB early during infection. Infect Immun 2014; 82:4878-88. [PMID: 25183730 DOI: 10.1128/iai.02131-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The enteric pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli employ a type 3 secretion system (T3SS) to manipulate the host inflammatory response during infection. Previously, it has been reported that EPEC, in a T3SS-dependent manner, induces an early proinflammatory response through activation of NF-κB via extracellular signal-regulated kinases 1 and 2 (ERK1/2) and protein kinase Cζ (PKCζ). However, the activation of NF-κB during infection has not yet been attributed to an effector. At later time points postinfection, NF-κB signaling is inhibited through the translocation of multiple effectors, including NleE and NleC. Here we report that the highly conserved non-LEE (locus of enterocyte effacement)-encoded effector F (NleF) shows both diffuse and mitochondrial localization during ectopic expression. Moreover, NleF induces the nuclear translocation of NF-κB p65 and the expression of interleukin 8 (IL-8) following ectopic expression and during EPEC infection. Furthermore, the proinflammatory activity and localization of NleF were dependent on the C-terminal amino acids LQCG. While the C-terminal domain of NleF has previously been shown to be essential for interaction with caspase-4, caspase-8, and caspase-9, the proinflammatory activity of NleF was independent of interaction with caspase-4, -8, or -9. In conclusion, EPEC, through the T3SS-dependent translocation of NleF, induces a proinflammatory response in an NF-κB-dependent manner in the early stages of infection.
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Abstract
ABSTRACT
The inflammatory response is an integral part of host defense against enterohemorrhagic
Escherichia coli
(EHEC) infection and also contributes to disease pathology. In this article we explore the factors leading to inflammation during EHEC infection and the mechanisms EHEC and other attaching and effacing (A/E) pathogens have evolved to suppress inflammatory signaling. EHEC stimulates an inflammatory response in the intestine through host recognition of bacterial components such as flagellin and lipopolysaccharide. In addition, the activity of Shiga toxin and some type III secretion system effectors leads to increased tissue inflammation. Various infection models of EHEC and other A/E pathogens have revealed many of the immune factors that mediate this response. In particular, the outcome of infection is greatly influenced by the ability of an infected epithelial cell to mount an effective host inflammatory response. The inflammatory response of infected enterocytes is counterbalanced by the activity of type III secretion system effectors such as NleE and NleC that modify and inhibit components of the signaling pathways that lead to proinflammatory cytokine production. Overall, A/E pathogens have taught us that innate mucosal immune responses in the gastrointestinal tract during infection with A/E pathogens are highly complex and ultimate clearance of the pathogen depends on multiple factors, including inflammatory mediators, bacterial burden, and the function and integrity of resident intestinal epithelial cells.
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Fraiture M, Brunner F. Killing two birds with one stone: trans-kingdom suppression of PAMP/MAMP-induced immunity by T3E from enteropathogenic bacteria. Front Microbiol 2014; 5:320. [PMID: 25101059 PMCID: PMC4105635 DOI: 10.3389/fmicb.2014.00320] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 06/11/2014] [Indexed: 01/07/2023] Open
Abstract
Within the past decade, remarkable similarities between the molecular organization of animal and plant systems for non-self discrimination were revealed. Obvious parallels exist between the molecular structures of the receptors mediating the recognition of pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs) with plant pattern recognition receptors strikingly resembling mammalian Toll-like receptors. Mitogen-activated protein kinase cascades, leading to the transcriptional activation of immunity-associated genes, illustrate the conservation of whole molecular building blocks of PAMP/MAMP-induced signaling. Enteropathogenic Salmonella and Escherichia coli use a type three secretion system (T3SS) to inject effector proteins into the mammalian host cell to subvert defense mechanisms and promote gut infection. Lately, disease occurrence was increasingly associated with bacteria-contaminated fruits and vegetables and common themes have emerged with regard to whether and how effectors target innate immune responses in a trans-kingdom manner. We propose that numerous Salmonella or E. coli effectors may be active in planta and tend to target central components (hubs) of immune signaling pathways.
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Affiliation(s)
- Malou Fraiture
- Plant Biochemistry, Centre for Plant Molecular Biology, Eberhard Karls University Tübingen Tübingen, Germany
| | - Frédéric Brunner
- Plant Biochemistry, Centre for Plant Molecular Biology, Eberhard Karls University Tübingen Tübingen, Germany
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Vossenkämper A, Hundsrucker C, Page K, van Maurik A, Sanders TJ, Stagg AJ, Das L, MacDonald TT. A CD3-specific antibody reduces cytokine production and alters phosphoprotein profiles in intestinal tissues from patients with inflammatory bowel disease. Gastroenterology 2014; 147:172-83. [PMID: 24704524 DOI: 10.1053/j.gastro.2014.03.049] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS T cells mediate the development of inflammation in inflammatory bowel disease (IBD). We investigated the effects of an antibody against CD3 called otelixizumab, which induces immune tolerance, in intestinal mucosa samples from patients. METHODS Intestinal tissues were isolated from patients undergoing routine endoscopy or from patients undergoing intestinal surgery for colon cancer or IBD; healthy surrounding tissues were collected as controls. Isolated lamina propria mononuclear cells (LPMCs) and mucosal tissue explants were incubated with otelixizumab for 24 or 48 hours. Production of inflammatory cytokines was determined by enzyme-linked immunosorbent assay. Levels of 36 cytokines and chemokines and phosphorylation of 39 receptor tyrosine kinases and signaling molecules were measured using protein arrays. Immunoblot analysis was used to analyze T-cell transcription factors. RESULTS Incubation of intestinal tissues or LPMCs with otelixizumab reduced production of interferon gamma, interleukin (IL)-17A, and other inflammatory cytokines and chemokines, simultaneously increasing production of IL-10. Mucosal biopsy specimens from patients with IBD retained inflammation-associated tyrosine phosphoprotein profiles ex vivo. Incubation of the inflamed tissue with otelixizumab reduced phosphorylation of these proteins to levels observed in control tissues. Otelixizumab also markedly reduced phosphorylation of proteins associated with T-cell receptor activation. Neutralization of IL-10 blocked the anti-inflammatory effects of otelixizumab. CONCLUSIONS We observed anti-inflammatory effects of anti-CD3 in inflamed intestinal tissues from patients with IBD. The antibody appears to down-regulate T-cell activation via IL-10.
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Affiliation(s)
- Anna Vossenkämper
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, Blizard Institute, London, England.
| | - Christian Hundsrucker
- Institute for Functional Genomics, Computational Diagnostics Group, University of Regensburg, Regensburg, Germany
| | - Kevin Page
- GlaxoSmithKline, Pharmaceuticals R&D Facility, Stevenage, Hertfordshire, England
| | - André van Maurik
- GlaxoSmithKline, Pharmaceuticals R&D Facility, Stevenage, Hertfordshire, England
| | - Theodore J Sanders
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, Blizard Institute, London, England
| | - Andrew J Stagg
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, Blizard Institute, London, England
| | - Lisa Das
- Centre for Digestive Diseases, Barts and The London School of Medicine and Dentistry, Blizard Institute, London, England
| | - Thomas T MacDonald
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, Blizard Institute, London, England
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Enteropathogenic Escherichia coli inhibits type I interferon- and RNase L-mediated host defense to disrupt intestinal epithelial cell barrier function. Infect Immun 2014; 82:2802-14. [PMID: 24733098 DOI: 10.1128/iai.00105-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) primarily infects children in developing countries and causes diarrhea that can be deadly. EPEC pathogenesis occurs through type III secretion system (T3SS)-mediated injection of effectors into intestinal epithelial cells (IECs); these effectors alter actin dynamics, modulate the immune response, and disrupt tight junction (TJ) integrity. The resulting compromised barrier function and increased gastrointestinal (GI) permeability may be responsible for the clinical symptoms of infection. Type I interferon (IFN) mediates anti-inflammatory activities and serves essential functions in intestinal immunity and homeostasis; however, its role in the immune response to enteric pathogens, such as EPEC, and its impact on IEC barrier function have not been examined. Here, we report that IFN-β is induced following EPEC infection and regulates IEC TJ proteins to maintain barrier function. The EPEC T3SS effector NleD counteracts this protective activity by inhibiting IFN-β induction and enhancing tumor necrosis factor alpha to promote barrier disruption. The endoribonuclease RNase L is a key mediator of IFN induction and action that promotes TJ protein expression and IEC barrier integrity. EPEC infection inhibits RNase L in a T3SS-dependent manner, providing a mechanism by which EPEC evades IFN-induced antibacterial activities. This work identifies novel roles for IFN-β and RNase L in IEC barrier functions that are targeted by EPEC effectors to escape host defense mechanisms and promote virulence. The IFN-RNase L axis thus represents a potential therapeutic target for enteric infections and GI diseases involving compromised barrier function.
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Two novel functions of hyaluronidase from Streptococcus agalactiae are enhanced intracellular survival and inhibition of proinflammatory cytokine expression. Infect Immun 2014; 82:2615-25. [PMID: 24711564 DOI: 10.1128/iai.00022-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Streptococcus agalactiae is the causative agent of septicemia and meningitis in fish. Previous studies have shown that hyaluronidase (Hyl) is an important virulence factor in many Gram-positive bacteria. To investigate the role of S. agalactiae Hyl during interaction with macrophages, we inactivated the gene encoding extracellular hyaluronidase, hylB, in a clinical Hyl(+) isolate. The isogenic hylb mutant (Δhylb) displayed reduced survival in macrophages compared to the wild type and stimulated a significantly higher release of proinflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α), than the wild type in macrophages as well as in mice. Furthermore, only Hyl(+) strains could grow utilizing hyaluronic acid (HA) as the sole carbon source, suggesting that Hyl permits the organism to utilize host HA as an energy source. Fifty percent lethal dose (LD50) determinations in zebrafish demonstrated that the hylb mutant was highly attenuated relative to the wild-type strain. Experimental infection of BALB/c mice revealed that bacterial loads in the blood, spleen, and brain at 16 h postinfection were significantly reduced in the ΔhylB mutant compared to those in wild-type-infected mice. In conclusion, hyaluronidase has a strong influence on the intracellular survival of S. agalactiae and proinflammatory cytokine expression, suggesting that it plays a key role in S. agalactiae pathogenicity.
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41
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Lactobacillus rhamnosus and its cell-free culture supernatant differentially modulate inflammatory biomarkers in Escherichia coli-challenged human dendritic cells. Br J Nutr 2014; 111:1727-37. [PMID: 24480321 DOI: 10.1017/s0007114513004303] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The intestinal immune system maintains a delicate balance between immunogenicity against invading pathogens and tolerance to the commensal microbiota and food antigens. Different strains of probiotics possess the ability to finely regulate the activation of dendritic cells (DC), polarising the subsequent activity of T-cells. Nevertheless, information about their underlying mechanisms of action is scarce. In the present study, we investigated the immunomodulatory effects of a potentially probiotic strain, Lactobacillus rhamnosus CNCM I-4036, and its cell-free culture supernatant (CFS) on human DC challenged with Escherichia coli. The results showed that the levels of pro-inflammatory cytokines such as IL-1β, IL-6, IL-8 and IL-12p70 were higher in the cells treated with live L. rhamnosus than in the cells treated with the CFS. In the presence of E. coli, the supernatant was more effective than the probiotic bacteria in reducing the secretion of pro-inflammatory cytokines. In addition, live L. rhamnosus potently induced the production of transforming growth factor (TGF)-β1 and TGF-β2, whereas the CFS increased the secretion of TGF-β1. However, in the presence of E. coli, both treatments restored the levels of TGF-β. The probiotic strain L. rhamnosus CNCM I-4036 and its CFS were able to activate the Toll-like receptor signalling pathway, enhancing innate immunity. The two treatments induced gene transcription of TLR-9. Live L. rhamnosus activated the expression of TLR-2 and TLR-4 genes, whereas the CFS increased the expression of TLR-1 and TLR-5 genes. In response to the stimulation with probiotic/CFS and E. coli, the expression of each gene tested was notably increased, with the exception of TNF-α and NFKBIA. In conclusion, the CFS exhibited an extraordinary ability to suppress the production of pro-inflammatory cytokines by DC, and may be used as an effective and safer alternative to live bacteria.
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Lutay N, Håkansson G, Alaridah N, Hallgren O, Westergren-Thorsson G, Godaly G. Mycobacteria bypass mucosal NF-kB signalling to induce an epithelial anti-inflammatory IL-22 and IL-10 response. PLoS One 2014; 9:e86466. [PMID: 24489729 PMCID: PMC3904915 DOI: 10.1371/journal.pone.0086466] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 12/13/2013] [Indexed: 01/20/2023] Open
Abstract
The mechanisms by which mycobacteria subvert the inflammatory defence to establish chronic infection remain an unresolved question in the pathogenesis of tuberculosis. Using primary epithelial cells, we have analysed mycobacteria induced epithelial signalling pathways from activation of TLRs to cytokine secretion. Mycobacterium bovis bacilli Calmette-Guerin induced phosphorylation of glycogen synthase kinase (GSK)3 by PI3K-Akt in the signalling pathway downstream of TLR2 and TLR4. Mycobacteria did not suppress NF-κB by activating the peroxisome proliferator-activated receptor γ. Instead the pro-inflammatory NF-κB was bypassed by mycobacteria induced GSK3 inhibition that promoted the anti-inflammatory transcription factor CREB. Mycobacterial infection did not thus induce mucosal pro-inflammatory response as measured by TNFα and IFNγ secretion, but led to an anti-inflammatory IL-10 and IL-22 production. Apart from CREB, MAP3Ks p38 and ERK1/2 activated the transcription factor AP-1 leading to IL-6 production. Interestingly, blocking of TLR4 before infection decreased epithelial IL-6 secretion, but increased the CREB-activated IL-10 production. Our data indicate that mycobacteria suppress epithelial pro-inflammatory production by suppressing NF-κB activation thereby shifting the infection towards an anti-inflammatory state. This balance between the host immune response and the pathogen could determine the outcome of infection.
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Affiliation(s)
- Nataliya Lutay
- Division of Laboratory Medicine, Department of MIG, Lund University, Lund, Sweden
| | - Gisela Håkansson
- Division of Laboratory Medicine, Department of MIG, Lund University, Lund, Sweden
| | - Nader Alaridah
- Division of Laboratory Medicine, Department of MIG, Lund University, Lund, Sweden
| | - Oskar Hallgren
- Division of Clinical Sciences, Department of Respiratory Medicine and Allergology, Lund University, Lund, Sweden
| | - Gunilla Westergren-Thorsson
- Division of Vascular- and Respiratory Research Unit of Lung Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Gabriela Godaly
- Division of Laboratory Medicine, Department of MIG, Lund University, Lund, Sweden
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43
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Shannon DA, Weerapana E. Orphan PTMs: Rare, yet functionally important modifications of cysteine. Biopolymers 2013; 101:156-64. [DOI: 10.1002/bip.22252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/01/2013] [Indexed: 12/16/2022]
Affiliation(s)
- D. Alexander Shannon
- Department of Chemistry; Merkert Chemistry Center, Boston College; Chestnut Hill MA 02467
| | - Eranthie Weerapana
- Department of Chemistry; Merkert Chemistry Center, Boston College; Chestnut Hill MA 02467
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44
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Pham TH, Gao X, Singh G, Hardwidge PR. Escherichia coli virulence protein NleH1 interaction with the v-Crk sarcoma virus CT10 oncogene-like protein (CRKL) governs NleH1 inhibition of the ribosomal protein S3 (RPS3)/nuclear factor κB (NF-κB) pathway. J Biol Chem 2013; 288:34567-74. [PMID: 24145029 DOI: 10.1074/jbc.m113.512376] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Enterohemorrhagic Escherichia coli and other attaching/effacing bacterial pathogens cause diarrhea in humans. These pathogens use a type III secretion system to inject virulence proteins (effectors) into host cells, some of which inhibit the innate immune system. The enterohemorrhagic E. coli NleH1 effector prevents the nuclear translocation of RPS3 (ribosomal protein S3) to inhibit its participation as a nuclear "specifier" of NF-κB binding to target gene promoters. NleH1 binds to RPS3 and inhibits its phosphorylation on Ser-209 by IκB kinase-β (IKKβ). However, the precise mechanism of this inhibition is unclear. NleH1 possesses a Ser/Thr protein kinase activity that is essential both for its ability to inhibit the RPS3/NF-κB pathway and for full virulence of the attaching/effacing mouse pathogen Citrobacter rodentium. However, neither RPS3 nor IKKβ is a substrate of NleH1 kinase activity. We therefore screened ∼9,000 human proteins to identify NleH1 kinase substrates and identified CRKL (v-Crk sarcoma virus CT10 oncogene-like protein), a substrate of the BCR/ABL kinase. Knockdown of CRKL abundance prevented NleH1 from inhibiting RPS3 nuclear translocation and NF-κB activity. CRKL residues Tyr-198 and Tyr-207 were required for interaction with NleH1. Lys-159, the kinase-active site of NleH1, was necessary for its interaction with CRKL. We also identified CRKL as an IKKβ interaction partner, mediated by CRKL Tyr-198. We propose that the CRKL interaction with IKKβ recruits NleH1 to the IKKβ complex, where NleH1 then inhibits the RPS3/NF-κB pathway.
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Affiliation(s)
- Thanh H Pham
- From the College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506 and
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45
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Li S, Zhang L, Yao Q, Li L, Dong N, Rong J, Gao W, Ding X, Sun L, Chen X, Chen S, Shao F. Pathogen blocks host death receptor signalling by arginine GlcNAcylation of death domains. Nature 2013; 501:242-6. [DOI: 10.1038/nature12436] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 07/08/2013] [Indexed: 12/25/2022]
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46
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Vossenkämper A, Blair PA, Safinia N, Fraser LD, Das L, Sanders TJ, Stagg AJ, Sanderson JD, Taylor K, Chang F, Choong LM, D'Cruz DP, Macdonald TT, Lombardi G, Spencer J. A role for gut-associated lymphoid tissue in shaping the human B cell repertoire. ACTA ACUST UNITED AC 2013; 210:1665-74. [PMID: 23940259 PMCID: PMC3754866 DOI: 10.1084/jem.20122465] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Transitional 2 B cells home to gut-associated lymphoid tissue and present an activated phenotype in healthy subjects, but gut immune compartments are depleted in SLE. We have tracked the fate of immature human B cells at a critical stage in their development when the mature B cell repertoire is shaped. We show that a major subset of bone marrow emigrant immature human B cells, the transitional 2 (T2) B cells, homes to gut-associated lymphoid tissue (GALT) and that most T2 B cells isolated from human GALT are activated. Activation in GALT is a previously unknown potential fate for immature human B cells. The process of maturation from immature transitional B cell through to mature naive B cell includes the removal of autoreactive cells from the developing repertoire, a process which is known to fail in systemic lupus erythematosus (SLE). We observe that immature B cells in SLE are poorly equipped to access the gut and that gut immune compartments are depleted in SLE. Thus, activation of immature B cells in GALT may function as a checkpoint that protects against autoimmunity. In healthy individuals, this pathway may be involved in generating the vast population of IgA plasma cells and also the enigmatic marginal zone B cell subset that is poorly understood in humans.
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Affiliation(s)
- Anna Vossenkämper
- Blizard Institute and 2 Digestive Diseases Clinical Academic Unit, Barts and the London School of Medicine and Dentistry, Whitechapel, London, England, UK.
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47
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Subversion of trafficking, apoptosis, and innate immunity by type III secretion system effectors. Trends Microbiol 2013; 21:430-41. [DOI: 10.1016/j.tim.2013.06.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/08/2013] [Accepted: 06/18/2013] [Indexed: 11/17/2022]
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48
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Law RJ, Gur-Arie L, Rosenshine I, Finlay BB. In vitro and in vivo model systems for studying enteropathogenic Escherichia coli infections. Cold Spring Harb Perspect Med 2013; 3:a009977. [PMID: 23457294 DOI: 10.1101/cshperspect.a009977] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) belong to a group of bacteria known as attaching and effacing (A/E) pathogens that cause disease by adhering to the lumenal surfaces of their host's intestinal epithelium. EPEC and EHEC are major causes of infectious diarrhea that result in significant childhood morbidity and mortality worldwide. Recent advances in in vitro and in vivo modeling of these pathogens have contributed to our knowledge of how EPEC and EHEC attach to host cells and subvert host-cell signaling pathways to promote infection and cause disease. A more detailed understanding of how these pathogenic microbes infect their hosts and how the host responds to infection could ultimately lead to new therapeutic strategies to help control these significant enteric pathogens.
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Affiliation(s)
- Robyn J Law
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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49
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Smith PJ, Wiltshire M, Chappell SC, Cosentino L, Burns PA, Pors K, Errington RJ. Kinetic analysis of intracellular Hoechst 33342-DNA interactions by flow cytometry: Misinterpretation of side population status? Cytometry A 2012; 83:161-9. [DOI: 10.1002/cyto.a.22224] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 09/14/2012] [Accepted: 10/06/2012] [Indexed: 12/30/2022]
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50
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Yan D, Wang X, Luo L, Cao X, Ge B. Inhibition of TLR signaling by a bacterial protein containing immunoreceptor tyrosine-based inhibitory motifs. Nat Immunol 2012; 13:1063-71. [PMID: 23001144 DOI: 10.1038/ni.2417] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 08/02/2012] [Indexed: 12/12/2022]
Abstract
The protein Tir (translocated intimin receptor) in enteric bacteria shares sequence similarity with the host cellular immunoreceptor tyrosine-based inhibition motifs (ITIMs). Despite the importance of Tir in pedestal formation, relatively little is known about the role of Tir and its ITIMs in the regulation of the host immune response. Here we demonstrate that Tir from enteropathogenic Escherichia coli (EPEC) interacted with the host cellular tyrosine phosphatase SHP-1 in an ITIM phosphorylation-dependent manner. The association of Tir with SHP-1 facilitated the recruitment of SHP-1 to the adaptor TRAF6 and inhibited the ubiquitination of TRAF6. Moreover, the ITIMs of Tir suppressed EPEC-stimulated expression of proinflammatory cytokines and inhibited intestinal immunity to infection with Citrobacter rodentium. Our findings identify a previously unknown mechanism by which bacterial ITIM-containing proteins can inhibit innate immune responses.
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Affiliation(s)
- Dapeng Yan
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & Shanghai Jiaotong University School of Medicine, Shanghai, China
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