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Ménard S, Lacroix-Lamandé S, Ehrhardt K, Yan J, Grassl GA, Wiedemann A. Cross-Talk Between the Intestinal Epithelium and Salmonella Typhimurium. Front Microbiol 2022; 13:906238. [PMID: 35733975 PMCID: PMC9207452 DOI: 10.3389/fmicb.2022.906238] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/13/2022] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica serovars are invasive gram-negative bacteria, causing a wide range of diseases from gastroenteritis to typhoid fever, representing a public health threat around the world. Salmonella gains access to the intestinal lumen after oral ingestion of contaminated food or water. The crucial initial step to establish infection is the interaction with the intestinal epithelium. Human-adapted serovars such as S. Typhi or S. Paratyphi disseminate to systemic organs and induce life-threatening disease known as typhoid fever, whereas broad-host serovars such as S. Typhimurium usually are limited to the intestine and responsible for gastroenteritis in humans. To overcome intestinal epithelial barrier, Salmonella developed mechanisms to induce cellular invasion, intracellular replication and to face host defence mechanisms. Depending on the serovar and the respective host organism, disease symptoms differ and are linked to the ability of the bacteria to manipulate the epithelial barrier for its own profit and cross the intestinal epithelium.This review will focus on S. Typhimurium (STm). To better understand STm pathogenesis, it is crucial to characterize the crosstalk between STm and the intestinal epithelium and decipher the mechanisms and epithelial cell types involved. Thus, the purpose of this review is to summarize our current knowledge on the molecular dialogue between STm and the various cell types constituting the intestinal epithelium with a focus on the mechanisms developed by STm to cross the intestinal epithelium and access to subepithelial or systemic sites and survive host defense mechanisms.
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Affiliation(s)
- Sandrine Ménard
- IRSD - Institut de Recherche en Santé Digestive, Université́ de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | | | - Katrin Ehrhardt
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hannover, Germany
| | - Jin Yan
- IRSD - Institut de Recherche en Santé Digestive, Université́ de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
- Department of Gastroenterology, The Second Xiangya Hospital of Central South University, Changsha, China
- Research Center of Digestive Disease, Central South University, Changsha, China
| | - Guntram A. Grassl
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hannover, Germany
| | - Agnès Wiedemann
- IRSD - Institut de Recherche en Santé Digestive, Université́ de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
- *Correspondence: Agnès Wiedemann,
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2
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de Pina LC, da Silva FSH, Galvão TC, Pauer H, Ferreira RBR, Antunes LCM. The role of two-component regulatory systems in environmental sensing and virulence in Salmonella. Crit Rev Microbiol 2021; 47:397-434. [PMID: 33751923 DOI: 10.1080/1040841x.2021.1895067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Adaptation to environments with constant fluctuations imposes challenges that are only overcome with sophisticated strategies that allow bacteria to perceive environmental conditions and develop an appropriate response. The gastrointestinal environment is a complex ecosystem that is home to trillions of microorganisms. Termed microbiota, this microbial ensemble plays important roles in host health and provides colonization resistance against pathogens, although pathogens have evolved strategies to circumvent this barrier. Among the strategies used by bacteria to monitor their environment, one of the most important are the sensing and signalling machineries of two-component systems (TCSs), which play relevant roles in the behaviour of all bacteria. Salmonella enterica is no exception, and here we present our current understanding of how this important human pathogen uses TCSs as an integral part of its lifestyle. We describe important aspects of these systems, such as the stimuli and responses involved, the processes regulated, and their roles in virulence. We also dissect the genomic organization of histidine kinases and response regulators, as well as the input and output domains for each TCS. Lastly, we explore how these systems may be promising targets for the development of antivirulence therapeutics to combat antibiotic-resistant infections.
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Affiliation(s)
- Lucindo Cardoso de Pina
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Programa de Pós-Graduação em Biociências, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.,Programa de Pós-Graduação Ciência para o Desenvolvimento, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Teca Calcagno Galvão
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Heidi Pauer
- Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Rio de Janeiro, Brazil
| | | | - L Caetano M Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Rio de Janeiro, Brazil.,Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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3
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Broadway PR, Carroll JA, Burdick Sanchez NC, Callaway TR, Lawhon SD, Gart EV, Bryan LK, Nisbet DJ, Hughes HD, Legako JF, O'Connor DL, Hergenreder JE, Rounds PW. Bacillus subtilis PB6 Supplementation in Weaned Holstein Steers During an Experimental Salmonella Challenge. Foodborne Pathog Dis 2020; 17:521-528. [PMID: 32349549 DOI: 10.1089/fpd.2019.2757] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To evaluate the effects of a patented Bacillus subtilis probiotic, weaned Holstein steers, not shedding Salmonella (n = 40; ∼90 kg), were supplemented (CLO) or not (CON) with CLOSTAT® (13 g/hd per day; Kemin Industries, Des Moines, IA) in a starter ration for 35 d. The calves were assigned to one of four treatments in a 2 × 2 factorial design with CLO and CON calves that were orally administered Salmonella (STM) or not (NoSTM). Calves were challenged with 1.6 × 106 colony-forming unit (CFU) Salmonella Typhimurium (resistant to 50 μg/mL nalidixic acid) in 1 L of milk replacer on day 0. Blood samples were collected through jugular catheters every 6 h for 96 h, and body temperature was measured every 5 min through indwelling rectal temperature recording devices. Five calves from each treatment were harvested 48 h postchallenge, and the remaining calves were harvested 96 h postchallenge. During necropsy, tissues were collected for the isolation and quantification of the inoculated STM from various tissues. The CLOSTM group had reduced STM concentrations in the jejunum, ileum, and transverse colon 48 h after the challenge (p ≤ 0.03), but were not different 96 h postchallenge (p > 0.05). Decreased (p < 0.01) pyrexia was observed after the challenge in CLOSTM calves when compared with CONSTM calves. White blood cells and lymphocyte counts were increased (p ≤ 0.05) in CLOSTM calves after the challenge in comparison with other treatments. In calves given STM, the CLO group had greater feed intake before and after the challenge (p < 0.01) compared with the CON group. Increased serum IL-6 and IFN-γ concentrations were observed in the CONSTM group compared with other treatments. Overall, CLO reduced Salmonella presence and concentrations in gastrointestinal tissues while simultaneously reducing the severity of the challenge as indicated by blood parameters and the reduced febrile response.
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Affiliation(s)
- Paul R Broadway
- USDA-ARS, Livestock Issues Research Unit, Lubbock, Texas, USA
| | | | | | - Todd R Callaway
- Department of Animal and Dairy Science, University of Georgia, Athens, Georgia, USA
| | - Sara D Lawhon
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, USA
| | - Elana V Gart
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, USA
| | - Laura K Bryan
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, USA
| | - David J Nisbet
- USDA-ARS Food and Feed Safety Research Unit, College Station, Texas, USA
| | | | - Jerrad F Legako
- Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA
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4
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Westermann AJ, Förstner KU, Amman F, Barquist L, Chao Y, Schulte LN, Müller L, Reinhardt R, Stadler PF, Vogel J. Dual RNA-seq unveils noncoding RNA functions in host-pathogen interactions. Nature 2016; 529:496-501. [PMID: 26789254 DOI: 10.1038/nature16547] [Citation(s) in RCA: 331] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 12/18/2015] [Indexed: 12/12/2022]
Abstract
Bacteria express many small RNAs for which the regulatory roles in pathogenesis have remained poorly understood due to a paucity of robust phenotypes in standard virulence assays. Here we use a generic 'dual RNA-seq' approach to profile RNA expression simultaneously in pathogen and host during Salmonella enterica serovar Typhimurium infection and reveal the molecular impact of bacterial riboregulators. We identify a PhoP-activated small RNA, PinT, which upon bacterial internalization temporally controls the expression of both invasion-associated effectors and virulence genes required for intracellular survival. This riboregulatory activity causes pervasive changes in coding and noncoding transcripts of the host. Interspecies correlation analysis links PinT to host cell JAK-STAT signalling, and we identify infection-specific alterations in multiple long noncoding RNAs. Our study provides a paradigm for a sensitive RNA-based analysis of intracellular bacterial pathogens and their hosts without physical separation, as well as a new discovery route for hidden functions of pathogen genes.
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Affiliation(s)
- Alexander J Westermann
- University of Würzburg, RNA Biology Group, Institute for Molecular Infection Biology, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany
| | - Konrad U Förstner
- University of Würzburg, RNA Biology Group, Institute for Molecular Infection Biology, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany.,University of Würzburg, Core Unit Systems Medicine, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany
| | - Fabian Amman
- University of Leipzig, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Härtelstraße 16-18, D-04107 Leipzig, Germany.,University of Vienna, Theoretical Biochemistry Group, Institute for Theoretical Chemistry, Währinger Straße 17, A-1090 Vienna, Austria
| | - Lars Barquist
- University of Würzburg, RNA Biology Group, Institute for Molecular Infection Biology, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany
| | - Yanjie Chao
- University of Würzburg, RNA Biology Group, Institute for Molecular Infection Biology, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany
| | - Leon N Schulte
- University of Würzburg, RNA Biology Group, Institute for Molecular Infection Biology, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany
| | - Lydia Müller
- University of Leipzig, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Härtelstraße 16-18, D-04107 Leipzig, Germany
| | - Richard Reinhardt
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
| | - Peter F Stadler
- University of Leipzig, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Härtelstraße 16-18, D-04107 Leipzig, Germany.,University of Vienna, Theoretical Biochemistry Group, Institute for Theoretical Chemistry, Währinger Straße 17, A-1090 Vienna, Austria.,Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, D-04103 Leipzig, Germany.,Santa Fe Institute, 1399 Hyde Park Rd, Santa Fe, New Mexico 87501, USA
| | - Jörg Vogel
- University of Würzburg, RNA Biology Group, Institute for Molecular Infection Biology, Josef-Schneider-Straße 2/D15, D-97080 Würzburg, Germany.,Research Centre for Infectious Diseases (ZINF), University of Würzburg, D-97070 Würzburg, Germany
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5
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Verma S, Srikanth CV. Understanding the complexities of Salmonella-host crosstalk as revealed by in vivo model organisms. IUBMB Life 2015; 67:482-97. [PMID: 26179888 DOI: 10.1002/iub.1393] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 06/15/2015] [Indexed: 01/03/2023]
Abstract
Foodborne infections caused by non-typhoidal Salmonellae, such as Salmonella enterica serovar Typhimurium (ST), pose a major challenge in the developed and developing world. With constant rise of drug-resistant strains, understanding the epidemiology, microbiology, pathogenesis and host-pathogen interactions biology is a mandatory requirement to enable health systems to be ready to combat these illnesses. Patient data from hospitals, at least from some parts of the world, have aided in epidemiological understanding of ST-mediated disease. Most of the other aspects connected to Salmonella-host crosstalk have come from model systems that offer convenience, genetic tractability and low maintenance costs that make them extremely valuable tools. Complex model systems such as the bovine model have helped in understanding key virulence factors needed for infection. Simple systems such as fruit flies and Caenorhabditis elegans have aided in identification of novel virulence factors, host pathways and mechanistic details of interactions. Some of the path-breaking concepts of the field have come from mice model of ST colitis, which allows genetic manipulations as well as high degree of similarity to human counterpart. Together, they are invaluable for correlating in vitro findings of ST-induced disease progression in vivo. The current review is a compilation of various advances of ST-host interactions at cellular and molecular levels that has come from investigations involving model organisms.
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Affiliation(s)
- Smriti Verma
- Regional Centre for Biotechnology, NCR Biotech Cluster 3rd Milestone, Gurgaon-Faridabad Highway, Village Bhankari, Faridabad, Haryana, India
| | - Chittur V Srikanth
- Regional Centre for Biotechnology, NCR Biotech Cluster 3rd Milestone, Gurgaon-Faridabad Highway, Village Bhankari, Faridabad, Haryana, India
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6
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Szmolka A, Wiener Z, Matulova ME, Varmuzova K, Rychlik I. Gene Expression Profiles of Chicken Embryo Fibroblasts in Response to Salmonella Enteritidis Infection. PLoS One 2015; 10:e0127708. [PMID: 26046914 PMCID: PMC4457728 DOI: 10.1371/journal.pone.0127708] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/17/2015] [Indexed: 12/30/2022] Open
Abstract
The response of chicken to non-typhoidal Salmonella infection is becoming well characterised but the role of particular cell types in this response is still far from being understood. Therefore, in this study we characterised the response of chicken embryo fibroblasts (CEFs) to infection with two different S. Enteritidis strains by microarray analysis. The expression of chicken genes identified as significantly up- or down-regulated (≥3-fold) by microarray analysis was verified by real-time PCR followed by functional classification of the genes and prediction of interactions between the proteins using Gene Ontology and STRING Database. Finally the expression of the newly identified genes was tested in HD11 macrophages and in vivo in chickens. Altogether 19 genes were induced in CEFs after S. Enteritidis infection. Twelve of them were also induced in HD11 macrophages and thirteen in the caecum of orally infected chickens. The majority of these genes were assigned different functions in the immune response, however five of them (LOC101750351, K123, BU460569, MOBKL2C and G0S2) have not been associated with the response of chicken to Salmonella infection so far. K123 and G0S2 were the only ’non-immune’ genes inducible by S. Enteritidis in fibroblasts, HD11 macrophages and in the caecum after oral infection. The function of K123 is unknown but G0S2 is involved in lipid metabolism and in β-oxidation of fatty acids in mitochondria.
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Affiliation(s)
- Ama Szmolka
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail:
| | - Zoltán Wiener
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Budapest, Hungary
| | | | | | - Ivan Rychlik
- Veterinary Research Institute, Brno, Czech Republic
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7
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Rychlik I, Elsheimer-Matulova M, Kyrova K. Gene expression in the chicken caecum in response to infections with non-typhoid Salmonella. Vet Res 2014; 45:119. [PMID: 25475706 PMCID: PMC4256799 DOI: 10.1186/s13567-014-0119-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 11/04/2014] [Indexed: 11/26/2022] Open
Abstract
Chickens can be infected with Salmonella enterica at any time during their life. However, infections within the first hours and days of their life are epidemiologically the most important, as newly hatched chickens are highly sensitive to Salmonella infection. Salmonella is initially recognized in the chicken caecum by TLR receptors and this recognition is followed by induction of chemokines, cytokines and many effector genes. This results in infiltration of heterophils, macrophages, B- and T-lymphocytes and changes in total gene expression in the caecal lamina propria. The highest induction in expression is observed for matrix metalloproteinase 7 (MMP7). Expression of this gene is increased in the chicken caecum over 4000 fold during the first 10 days after the infection of newly hatched chickens. Additional highly inducible genes in the caecum following S. Enteritidis infection include immune responsive gene 1 (IRG1), serum amyloid A (SAA), extracellular fatty acid binding protein (ExFABP), serine protease inhibitor (SERPINB10), trappin 6-like (TRAP6), calprotectin (MRP126), mitochondrial ES1 protein homolog (ES1), interferon-induced protein with tetratricopeptide repeats 5 (IFIT5), avidin (AVD) and transglutaminase 4 (TGM4). The induction of expression of these proteins exceeds a factor of 50. Similar induction rates are also observed for chemokines and cytokines such as IL1β, IL6, IL8, IL17, IL18, IL22, IFNγ, AH221 or iNOS. Once the infection is under control, which happens approx. 2 weeks after infection, expression of IgY and IgA increases to facilitate Salmonella elimination from the gut lumen. This review outlines the function of individual proteins expressed in chickens after infection with non-typhoid Salmonella serovars.
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Affiliation(s)
- Ivan Rychlik
- Veterinary Research Institute, Hudcova 70, Brno, 621 00, Czech Republic.
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8
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Hurley D, McCusker MP, Fanning S, Martins M. Salmonella-host interactions - modulation of the host innate immune system. Front Immunol 2014; 5:481. [PMID: 25339955 PMCID: PMC4188169 DOI: 10.3389/fimmu.2014.00481] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 09/20/2014] [Indexed: 12/27/2022] Open
Abstract
Salmonella enterica (S. enterica) are Gram-negative bacteria that can invade a broad range of hosts causing both acute and chronic infections. This phenotype is related to its ability to replicate and persist within non-phagocytic host epithelial cells as well as phagocytic dendritic cells and macrophages of the innate immune system. Infection with S. enterica manifests itself through a broad range of clinical symptoms and can result in asymptomatic carriage, gastroenteritis, systemic disease such as typhoid fever and in severe cases, death (1). Exposure to S. enterica serovars Typhi and Paratyphi exhibits clinical symptoms including diarrhea, fatigue, fever, and temperature fluctuations. Other serovars such as the non-typhoidal Salmonella (NTS), of which there are over 2,500, are commonly contracted as, but not limited to, food-borne sources causing gastrointestinal symptoms, which include diarrhea and vomiting. The availability of complete genome sequences for many S. enterica serovars has facilitated research into the genetic determinants of virulence for this pathogen. This work has led to the identification of important bacterial components, including flagella, type III secretion systems, lipopolysaccharides, and Salmonella pathogenicity islands, all of which support the intracellular life cycle of S. enterica. Studies focusing on the host-pathogen interaction have provided insights into receptor activation of the innate immune system. Therefore, characterizing the host-S. enterica interaction is critical to understand the pathogenicity of the bacteria in a clinically relevant context. This review outlines salmonellosis and the clinical manifestations between typhoidal and NTS infections as well as discussing the host immune response to infection and the models that are being used to elucidate the mechanisms involved in Salmonella pathogenicity.
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Affiliation(s)
- Daniel Hurley
- School of Public Health, Physiotherapy and Population Science, UCD Centre for Food Safety, UCD Centre for Molecular Innovation and Drug Discovery, University College Dublin , Dublin , Ireland
| | - Matthew P McCusker
- School of Public Health, Physiotherapy and Population Science, UCD Centre for Food Safety, UCD Centre for Molecular Innovation and Drug Discovery, University College Dublin , Dublin , Ireland
| | - Séamus Fanning
- School of Public Health, Physiotherapy and Population Science, UCD Centre for Food Safety, UCD Centre for Molecular Innovation and Drug Discovery, University College Dublin , Dublin , Ireland
| | - Marta Martins
- School of Public Health, Physiotherapy and Population Science, UCD Centre for Food Safety, UCD Centre for Molecular Innovation and Drug Discovery, University College Dublin , Dublin , Ireland
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9
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Agbor TA, Demma Z, Mrsny RJ, Castillo A, Boll EJ, McCormick BA. The oxido-reductase enzyme glutathione peroxidase 4 (GPX4) governs Salmonella Typhimurium-induced neutrophil transepithelial migration. Cell Microbiol 2014; 16:1339-53. [PMID: 24617613 PMCID: PMC4146641 DOI: 10.1111/cmi.12290] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 03/03/2014] [Accepted: 03/05/2014] [Indexed: 01/21/2023]
Abstract
Neutrophil (polymorphonuclear leucocytes; PMN) transmigration across mucosal surfaces contributes to dysfunction of epithelial barrier properties, a characteristic underlying many mucosal inflammatory diseases. Using Salmonella enterica serovar Typhimurium (S. Typhimurium) as a prototypic proinflammatory insult, we have previously reported that the eicosanoid hepoxilin A3 (HXA3), an endogenous product of 12-lipoxygenase (12-LOX) activity, is secreted from the apical surface of the intestinal epithelium to establish a chemotactic gradient that guides PMN across the epithelial surface. Since little is known regarding the molecular mechanisms that regulate 12-LOX during S. Typhimurium infection, we investigated this pathway. We found that expression of phospholipid glutathione peroxidase (GPX4), which is known to have an inhibitory effect on 12-LOX activity, is significantly decreased at both the mRNA and protein level during infection with S. Typhimurium. Moreover, employing intestinal epithelial cell monolayers expressing siRNA against GPX4 mRNA, S. Typhimurium-induced PMN migration was significantly increased compared with the non-specific siRNA control cells. Conversely, in cells engineered to overexpress GPX4, S. Typhimurium-induced PMN migration was significantly decreased, which is consistent with the finding that partial depletion of GPX4 by RNAi resulted in a significant increase in HXA3 secretion during S. Typhimurium infection. Mechanistically, although we found Salmonella entry not to be required for the induced decrease in GPX4, the secreted effector, SipA, which is known to induce epithelial responses leading to stimulation of HXA3, governed the decrease in GPX4 in a process that does not lead to an overall increase in the levels of ROS. Taken together, these results suggest that S. Typhimurium induces apical secretion of HXA3 by decreasing the expression of phospholipid GPX, which in turn leads to an increase in 12-LOX activity, and hence HXA3 synthesis.
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Affiliation(s)
- Terence A Agbor
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA, 01655, USA
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10
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Pathogenesis of human enterovirulent bacteria: lessons from cultured, fully differentiated human colon cancer cell lines. Microbiol Mol Biol Rev 2014; 77:380-439. [PMID: 24006470 DOI: 10.1128/mmbr.00064-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses.
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11
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Repression of flagella is a common trait in field isolates of Salmonella enterica serovar Dublin and is associated with invasive human infections. Infect Immun 2014; 82:1465-76. [PMID: 24421045 DOI: 10.1128/iai.01336-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The nontyphoidal Salmonella enterica serovar Dublin is adapted to cattle but infrequently infects humans, very often resulting in invasive infections with high levels of morbidity and mortality. A Salmonella-induced intestinal acute inflammatory response is postulated as a mechanism to prevent bacterial dissemination to systemic sites. In S. enterica serovar Typhimurium, flagella contribute to this response by providing motility and FliC-mediated activation of pattern recognition receptors. In this study, we found 4 Salmonella enterica isolates, with the antigenic formula 9,12:-:-, that, based on fliC sequence and multilocus sequence type (MLST) analyses, are aflagellate S. Dublin isolates. Interestingly, all were obtained from human bloodstream infections. Thus, we investigated the potential role of flagella in the unusual invasiveness exhibited by S. Dublin in humans by analyzing flagellation and proinflammatory properties of a collection of 10 S. Dublin human clinical isolates. We found that 4 of 7 blood isolates were aflagellate due to significantly reduced levels of fliC expression, whereas all 3 isolates from other sources were flagellated. Lack of flagella correlated with a reduced ability of triggering interleukin-8 (IL-8) and CCL20 chemokine expression in human intestinal Caco-2 cells and with reduced early inflammation in the ceca of streptomycin-pretreated C57/BL6 mice. These results indicate that flagella contribute to the host intestinal inflammatory response to Salmonella serovar Dublin and suggest that their absence may contribute to its systemic dissemination through dampening of the gut immune response. Analysis of FliC production in a collection of cattle isolates indicated that the aflagellate phenotype is widely distributed in field isolates of S. Dublin.
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12
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Arikawa K, Meraz IM, Nishikawa Y, Ogasawara J, Hase A. Interleukin-8 Secretion by Epithelial Cells Infected with Diffusely AdherentEscherichia coliPossessing Afa Adhesin-Coding Genes. Microbiol Immunol 2013; 49:493-503. [PMID: 15965296 DOI: 10.1111/j.1348-0421.2005.tb03754.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Escherichia coli that adhere sparsely to human epithelial (HEp-2) cells are known as diffusely adherent E. coli(DAEC) and considered potentially diarrheagenic. The role of the afimbrial adhesive sheath (Afa)-identified originally as a uropathogenic factor-in diffuse adhesion is now understood. However, the role of DAEC in diarrheal disease remains controversial. Recently, ability to induce interleukin-8 (IL-8) secretion from intestinal epithelial cells has been suggested as one of the properties of enterovirulent bacteria. In this study, we examined whether DAEC strains possessing Afa genes induced IL-8 in cultures of human carcinoma epithelial cells (e.g., HEp-2, Caco-2, and T84). Nineteen afa-positive DAEC strains were examined for their ability to induce IL-8 secretion, and only 7 strains (37%; 7/19) induced IL-8 as much as enteroaggregative E. coli did. No marked differences in adhesion were observed between high and low inducers. Diffusive adhesiveness itself is unlikely to be sufficient to induce IL-8. All high inducers were motile and others were nonmotile. Additional stimulation by flagella may be required to cause high levels of chemokine induction. Motility or presence of flagella can be an important criterion to predict DAEC diarrheagenicity at clinical laboratories.
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Affiliation(s)
- Kentaro Arikawa
- Department of Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, Japan
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Hulst M, Smits M, Vastenhouw S, de Wit A, Niewold T, van der Meulen J. Transcription networks responsible for early regulation of Salmonella-induced inflammation in the jejunum of pigs. JOURNAL OF INFLAMMATION-LONDON 2013; 10:18. [PMID: 23590759 PMCID: PMC3637394 DOI: 10.1186/1476-9255-10-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 04/10/2013] [Indexed: 05/16/2023]
Abstract
Background The aim of this study was to identify transcription factors/regulators that play a crucial role in steering the (innate) immune response shortly (within a few hours) after the first contact of the intestinal mucosa with an inflammatory mediator, and to test whether the processes regulated by these factors/regulators can be modulated by chemical substances of natural origin. Methods We experimentally induced inflammation by perfusion of surgically applied jejunal loops with Salmonella enterica subspecies enterica serovar Typhimurium DT104 in three pigs. Segments of mock and Salmonella treated loops were dissected after 2, 4 and 8 hours of perfusion. IL8 and IL1-beta mRNA expression levels were measured in mucosal scrapings of all segments. Furthermore, intra-animal microarray comparisons (isogenic) between Salmonella and mock treated segments after 8 hours, and inter-animal comparisons between similar Salmonella-treated loops of each pig at 2 and 4 hours, were performed. Results IL-1beta and IL8 mRNA levels, and intra-animal microarray comparisons at 8 hours between Salmonella and mock treated segments showed that the response-time and type of response to Salmonella was different in all three pigs. This plasticity allowed us to extract a comprehensive set of differentially expressed genes from inter-animal comparisons at 2 and 4 hours. Pathway analysis indicated that many of these genes play a role in induction and/or tempering the inflammatory response in the intestine. Among them a set of transcription factors/regulators known to be involved in regulation of inflammation, but also factors/regulators for which involvement was not expected. Nine out of twenty compounds of natural origin, which according to literature had the potential to modulate the activity of these factors/regulators, were able to stimulate or inhibit a Salmonella-induced mRNA response of inflammatory-reporter genes IL8 and/or nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha in cultured intestinal porcine epithelial cells. Conclusions We describe a set of transcription factors/regulators possibly involved in regulation of “very early” immune mechanism which determines the inflammatory status of the intestine later on. In addition, we show that these mechanisms may be modulated by chemical substances of natural origin.
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Affiliation(s)
- Marcel Hulst
- Livestock Research of Wageningen University and Research Centre, P,O, Box 65, Lelystad, 8200AB, The Netherlands.
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Ahmed I, Roy B, Chandrakesan P, Venugopal A, Xia L, Jensen R, Anant S, Umar S. Evidence of functional cross talk between the Notch and NF-κB pathways in nonneoplastic hyperproliferating colonic epithelium. Am J Physiol Gastrointest Liver Physiol 2013; 304:G356-70. [PMID: 23203159 PMCID: PMC3566617 DOI: 10.1152/ajpgi.00372.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 11/28/2012] [Indexed: 01/31/2023]
Abstract
The Notch and NF-κB signaling pathways regulate stem cell function and inflammation in the gut, respectively. We investigate whether a functional cross talk exists between the two pathways during transmissible murine colonic hyperplasia (TMCH) caused by Citrobacter rodentium (CR). During TMCH, NF-κB activity and subunit phosphorylation in colonic crypts of NIH Swiss mice at days 6 and 12 were associated with increases in downstream target CXC chemokine ligand (CXCL)-1/keratinocyte-derived chemokine (KC) expression. Blocking Notch signaling acutely for 5 days with the Notch blocker dibenzazepine (DBZ) failed to inhibit crypt NF-κB activity or CXCL-1/KC expression. Chronic DBZ administration for 10 days, however, blocked Notch and NF-κB signaling in the crypts and abrogated hyperplasia. Intriguingly, chronic Notch inhibition was associated with significant increases in IL-1α, granulocyte colony-stimulating factor, monocyte chemoattractant protein 1, macrophage inflammatory protein 2, and KC in the crypt-denuded lamina propria or whole distal colon, with concomitant increases in myeloperoxidase activity. In core-3(-/-) mice, which are defective in intestinal mucin, DBZ administration replicated the results of NIH Swiss mice; in Apc(Min/+) mice, which are associated with CR-induced elevation of NF-κB-p65(276) expression, DBZ reversed the increase in NF-κB-p65(276), which may have blocked rapid proliferation of the mutated crypts. DBZ further blocked reporter activities involving the NF-κB-luciferase reporter plasmid or the Toll-like receptor 4/NF-κB/SEAPorter HEK-293 reporter cell line, while ectopic expression of Notch-N(ICD) reversed the inhibitory effect. Dietary bael (Aegle marmelos) extract (4%) and curcumin (4%) restored Notch and NF-κB cross talk in NIH Swiss mice, inhibited CR/DBZ-induced apoptosis in the crypts, and promoted crypt regeneration. Thus functional cross talk between the Notch and NF-κB pathways during TMCH regulates hyperplasia and/or inflammation in response to CR infection.
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Affiliation(s)
- Ishfaq Ahmed
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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15
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Agbor TA, Demma ZC, Mumy KL, Bien JD, McCormick BA. The ERM protein, ezrin, regulates neutrophil transmigration by modulating the apical localization of MRP2 in response to the SipA effector protein during Salmonella Typhimurium infection. Cell Microbiol 2011; 13:2007-21. [PMID: 21899702 DOI: 10.1111/j.1462-5822.2011.01693.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In human disease induced by Salmonella enterica serovar Typhimurium (S. Typhimurium), transepithelial migration of neutrophils rapidly follows attachment of the bacteria to the epithelial apical membrane. We have previously shown that during S. Typhimurium infection the multidrug resistance-associated protein 2 (MRP2) is highly expressed at the apical surface of the intestinal epithelia, and that it functions as an efflux pump for the potent neutrophil chemoattractant hepoxilin A(3) . However, the molecular mechanisms regulating its apical localization during active states of inflammation remain unknown. Thus, our objective was to determine the mechanistic basis for the translocation of MRP2 to the apical surface of intestinal epithelial cells during S. Typhimurium infection. We show that suppression of ezrin, through either RNAi or truncation of the C-terminus, results not only in a decrease in S. Typhimurium-induced neutrophil transmigration but also significantly attenuates the apical membrane expression of MRP2 during Salmonella infection. In addition, we determined that S. Typhimurium induces the activation of ezrin via a PKC-α-dependent pathway and that ezrin activation is coupled to apical localization of MRP2. Based on these results we propose that activation of ezrin is required for the apical localization of MRP2 during S. Typhimurium infection.
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Affiliation(s)
- Terence A Agbor
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA
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16
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Huang FC. Plasma membrane cholesterol plays a critical role in the Salmonella-induced anti-inflammatory response in intestinal epithelial cells. Cell Immunol 2011; 271:480-7. [PMID: 21943646 DOI: 10.1016/j.cellimm.2011.08.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 06/17/2011] [Accepted: 08/24/2011] [Indexed: 01/18/2023]
Abstract
Our recent study demonstrated that a phosphatidylinositol-3 kinase (PI3K)/Akt-dependent anti-inflammatory pathway was activated by Salmonella in intestinal epithelial cells. Salmonella virulence is dependent on the ability of the bacterium to invade nonphagocytic host cells and then survive and replicate within modified Salmonella-containing vacuoles where cholesterol accumulates. In addition, cholesterol in membrane lipid rafts is frequently a platform for the activation of downstream signaling pathways, including the PI3K/Akt pathway. However, the role of plasma membrane cholesterol in the Salmonella-induced anti-inflammatory response in intestinal epithelial cells has not been elucidated. Here, we show that the effect of plasma membrane cholesterol depletion on the inhibition of Akt activation allows sustained ERK activation and the subsequent upregulation of IL-8 expression. These results demonstrate that plasma membrane cholesterol plays a critical role in the PI3K-dependent anti-inflammatory pathway activated by Salmonella in intestinal epithelial cells.
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Affiliation(s)
- Fu-Chen Huang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Niao-sung District, Kaohsiung City, Taiwan.
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17
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Intestinal epithelia activate anti-viral signaling via intracellular sensing of rotavirus structural components. Mucosal Immunol 2010; 3:622-32. [PMID: 20664578 PMCID: PMC2957552 DOI: 10.1038/mi.2010.39] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Rotavirus (RV), a leading cause of severe diarrhea, primarily infects intestinal epithelial cells (IECs) causing self-limiting illness. To better understand innate immunity to RV, we sought to define the extent to which IEC activation of anti-viral responses required viral replication or could be recapitulated by inactivated RV or its components. Using model human intestinal epithelia, we observed that RV-induced activation of signaling events and gene expression typically associated with viral infection was largely mimicked by administration of ultraviolet (UV)-inactivated RV. Use of anti-interferon (IFN) neutralizing antibodies revealed that such replication-independent anti-viral gene expression required type I IFN signaling. In contrast, RV-induction of nuclear factor-κB-mediated interleukin-8 expression was dependent on viral replication. The anti-viral gene expression induced by UV-RV was not significantly recapitulated by RV RNA or RV virus-like particles although the latter could enter IEC. Together, these results suggest that RV proteins mediate viral entry into epithelial cells leading to intracellular detection of RV RNA that generates an anti-viral response.
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18
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Erjefält JS. The airway epithelium as regulator of inflammation patterns in asthma. CLINICAL RESPIRATORY JOURNAL 2010; 4 Suppl 1:9-14. [PMID: 20500604 DOI: 10.1111/j.1752-699x.2010.00191.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Asthma is a complex, heterogeneous and mutifactorial disease and represents a major health problem in Westernized countries. The airway epithelium, with its direct physical contact with luminal triggers, has a major role in determining the nature of inflammation that develops in asthmatic airways. OBJECTIVE The present review aims to provide a brief overview of the numerous ways the airway epithelium can affect and influence the histopathological picture in asthma. RESULTS AND CONCLUSION The ways the epithelium aggravates inflammation range from acute responses to luminal triggers such as allergens and infections to the multipathogenic events occurring as a consequence of repeated epithelial damage-repair responses. The airway epithelium also facilitates the selective migration of leukocytes into the airway lumen, a process that is important in regulating inflammatory cell homeostasis. The fact that only some of the important leukocyte subtypes participate in this process cause translational problems and difficulties in the interpretation of luminal samples. To further reveal the nature of the multifaceted involvement of the airway epithelium in inflamed asthmatic airways emerges as a promising goal for identifying new therapeutic strategies.
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Affiliation(s)
- Jonas Sten Erjefält
- Unit of Airway Inflammation, Department of Experimental Medical Science, BMC D12, Lund University, Lund, Sweden.
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19
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Lahiri A, Lahiri A, Iyer N, Das P, Chakravortty D. Visiting the cell biology of Salmonella infection. Microbes Infect 2010; 12:809-18. [PMID: 20538070 DOI: 10.1016/j.micinf.2010.05.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 05/27/2010] [Accepted: 05/27/2010] [Indexed: 10/19/2022]
Abstract
Salmonella, a Gram-negative facultative intracellular pathogen is capable of infecting vast array of hosts. The striking ability of Salmonella to overcome every hurdle encountered in the host proves that they are true survivors. In the host, Salmonella infects various cell types and needs to survive and replicate by countering the defense mechanism of the specific cell. In this review, we will summarize the recent insights into the cell biology of Salmonella infection. Here, we will focus on the findings that deal with the specific mechanism of various cell types to control Salmonella infection. Further, the survival strategies of the pathogen in response to the host immunity will also be discussed in detail. Better understanding of the mechanisms by which Salmonella evade the host defense system and establish pathogenesis will be critical in disease management.
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Affiliation(s)
- Amit Lahiri
- Center for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
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20
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Trebichavský I, Šplíchal I, Šplíchalová A. Innate immune response in the gut against Salmonella — review. Folia Microbiol (Praha) 2010; 55:295-300. [DOI: 10.1007/s12223-010-0044-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 03/25/2010] [Indexed: 12/25/2022]
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21
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Bayoumi MA, Griffiths MW. Probiotics down-regulate genes in Salmonella enterica serovar typhimurium pathogenicity islands 1 and 2. J Food Prot 2010; 73:452-60. [PMID: 20202329 DOI: 10.4315/0362-028x-73.3.452] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Salmonella Typhimurium pathogenesis relies mainly on the expression of genes of two pathogenicity islands, Salmonella pathogenicity islands 1 and 2 (SPI1 and SPI2). Each island has its own pattern of expression and regulation. Success in suppression of the responsible key activator of each island would be an effective way of controlling Salmonella, especially with the emerging problem of antibiotic-resistant strains. Probiotics have been shown to inhibit several foodborne pathogens, and their mode of action may partly involve down-regulation of virulence genes. To investigate whether probiotics played a role in the regulation of the pathogenicity islands SPI1 and SPI2 in Salmonella, two reporter strains were constructed in which the general regulator of SPI1, hilA, and the response regulator of SPI2, ssrB, were fused with luxCDABE genes. These constructs were used to screen the effect of probiotics on the expression of each gene. Molecules secreted by Bifidobacterium bifidum were able to down-regulate both genes.
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Affiliation(s)
- Mohamed A Bayoumi
- Food Control Department, Faculty of Veterinary Medicine, Zagazig University, 44519, Zagazig, Egypt
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22
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Stevens MP, Humphrey TJ, Maskell DJ. Molecular insights into farm animal and zoonotic Salmonella infections. Philos Trans R Soc Lond B Biol Sci 2009; 364:2709-23. [PMID: 19687040 PMCID: PMC2865095 DOI: 10.1098/rstb.2009.0094] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica is a facultative intracellular pathogen of worldwide importance. Infections may present in a variety of ways, from asymptomatic colonization to inflammatory diarrhoea or typhoid fever depending on serovar- and host-specific factors. Human diarrhoeal infections are frequently acquired via the food chain and farm environment by virtue of the ability of selected non-typhoidal serovars to colonize the intestines of food-producing animals and contaminate the avian reproductive tract and egg. Colonization of reservoir hosts often occurs in the absence of clinical symptoms; however, some S. enterica serovars threaten animal health owing to their ability to cause acute enteritis or translocate from the intestines to other organs causing fever, septicaemia and abortion. Despite the availability of complete genome sequences of isolates representing several serovars, the molecular mechanisms underlying Salmonella colonization, pathogenesis and transmission in reservoir hosts remain ill-defined. Here we review current knowledge of the bacterial factors influencing colonization of food-producing animals by Salmonella and the basis of host range, differential virulence and zoonotic potential.
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Affiliation(s)
- Mark P Stevens
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire RG20 7NN, UK.
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23
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Burkey TE, Skjolaas KA, Dritz SS, Minton JE. Expression of porcine Toll-like receptor 2, 4 and 9 gene transcripts in the presence of lipopolysaccharide and Salmonella enterica serovars Typhimurium and Choleraesuis. Vet Immunol Immunopathol 2009; 130:96-101. [PMID: 19200608 DOI: 10.1016/j.vetimm.2008.12.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 12/23/2008] [Accepted: 12/24/2008] [Indexed: 10/21/2022]
Abstract
Salmonella enterica serovar Typhimurium (ST) and Choleraesuis (SC) are among the most frequently isolated salmonellae serovars causing enteric disease in swine. Enteric disease in young pigs is of major concern in modern production systems due to the negative implications on animal health, food safety and economic return. Epithelial cells express Toll-like receptors (TLR) that recognize conserved microbial structures and act as mediators of innate and adaptive immune responses. However, little is known about the expression of TLR gene transcripts in swine. The objective of the current study was to characterize the relative abundance of porcine TLR2, 4 and 9 gene transcripts in vitro in a porcine jejunal epithelial cell line (IPEC-J2) and in porcine mononuclear phagocytes (pMP) in the presence of ST or SC, as well as in vivo in the distal ileum of pigs orally challenged with ST. Our results indicate that TLR2, 4 and 9 are constitutively expressed in vitro in IPEC-J2 cells and pMP and in vivo in the distal ileum. Additionally, transient modulation of porcine TLR was observed in vitro and in vivo in the presence of ST and SC. Further investigation is warranted to determine the effects of ST and SC on functional TLR.
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Affiliation(s)
- T E Burkey
- Animal Science Department, University of Nebraska, C206F Animal Science, Lincoln, NE 68583, USA.
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24
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Interactions of the intestinal epithelium with the pathogen and the indigenous microbiota: a three-way crosstalk. Interdiscip Perspect Infect Dis 2008; 2008:626827. [PMID: 19259328 PMCID: PMC2648619 DOI: 10.1155/2008/626827] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 08/08/2008] [Indexed: 12/24/2022] Open
Abstract
The mucosal surfaces of the gastrointestinal tract harbor a vast number of commensal microbiota that have coevolved with the host, and in addition display one of the most complex relationships with the host. This relationship affects several important aspects of the biology of the host including the synthesis of nutrients, protection against infection, and the development of the immune system. On the other hand, despite the existence of several lines of mucosal defense mechanisms, pathogenic organisms such as Shigella and Salmonella have evolved sophisticated virulence strategies for breaching these barriers. The constant challenge from these pathogens and the attempts by the host to counter them set up a dynamic equilibrium of cellular and molecular crosstalk. Even slight perturbations in this equilibrium may be detrimental to the host leading to severe bacterial infection or even autoimmune diseases like inflammatory bowel disease. Several experimental model systems, including germ-free mice and antibiotic-treated mice, have been used by various researchers to study this complex relationship. Although it is only the beginning, it promises to be an exciting era in the study of these host-microbe relationships.
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25
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Cholera toxin, E. coli heat-labile toxin, and non-toxic derivatives induce dendritic cell migration into the follicle-associated epithelium of Peyer's patches. Mucosal Immunol 2008; 1:59-67. [PMID: 19079161 PMCID: PMC2614317 DOI: 10.1038/mi.2007.7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The follicle-associated epithelium (FAE) of Peyer's patches (PPs) transports antigens and microorganisms into mucosal lymphoid tissues where they are captured by subepithelial dendritic cells (DCs). Feeding of cholera toxin (CT) induced migration of subepithelial DCs to interfollicular T-cell areas within 24 h. This study investigated short-term effects of CT, Escherichia coli heat-labile toxin, and non-toxic derivatives on DC migration. CT or CTB injected into ligated intestinal loops induced significant increase in CD11c+ DCs within the FAE within 90 min. In mice fed CT intragastrically, DC numbers in the FAE increased by 1 h, were maximal by 2 h, declined between 8 and 12 h, and were reversed by 24 h. Feeding of native LT, recombinant CTB, dibutyryl cyclic AMP, and to a lesser extent mutated CT(E29H) or mutated LT(R192G) had the same effect. Thus, both A and B subunits of enterotoxins, presumably acting through distinct signaling pathways, may promote capture of incoming antigens and pathogens by PP DCs.
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Volf J, Boyen F, Faldyna M, Pavlova B, Navratilova J, Rychlik I. Cytokine response of porcine cell lines to Salmonella enterica serovar typhimurium and its hilA and ssrA mutants. Zoonoses Public Health 2007; 54:286-93. [PMID: 17894638 DOI: 10.1111/j.1863-2378.2007.01064.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative intracellular bacterium which can infect and colonize pigs. After contact with enterocytes and macrophages, S. Typhimurium induces production of cytokines thus triggering the innate immune response. In this study we evaluated the cytokine response of two porcine cell lines, IPI-2I and 3D4/31, of epithelial or macrophage origins, respectively, to the wild-type S. Typhimurium and its hilA and ssrA mutants. We observed that the 3D4/31 cell line essentially did not respond to S. Typhimurium infection when a medium with foetal calf serum was used. However when the 3D4 cell line was incubated overnight in the presence of porcine serum, it efficiently responded to the wild-type strain and the ssrA mutant but not to the noninvasive hilA mutant as measured by mRNA quantification of TNF-alpha, IL-8 and GM-CSF by the real-time RT-PCR. In IPI-2I, all the cytokines were also induced by the wild-type S. Typhimurium and the ssrA mutant although the induction of TNF-alpha was lower than that induced by the wild-type strain. The hilA mutant was unable to induce any of the cytokines tested. The ssrA mutant can therefore be considered as more suitable for further vaccine development as the stimulation of innate immune response is important for animal protection against a challenge with virulent strains.
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Affiliation(s)
- J Volf
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic
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27
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Hautefort I, Thompson A, Eriksson-Ygberg S, Parker ML, Lucchini S, Danino V, Bongaerts RJM, Ahmad N, Rhen M, Hinton JCD. During infection of epithelial cells Salmonella enterica serovar Typhimurium undergoes a time-dependent transcriptional adaptation that results in simultaneous expression of three type 3 secretion systems. Cell Microbiol 2007; 10:958-84. [PMID: 18031307 PMCID: PMC2343689 DOI: 10.1111/j.1462-5822.2007.01099.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The biogenesis of the Salmonella-containing vacuole within mammalian cells has been intensively studied over recent years. However, the ability of Salmonella to sense and adapt to the intracellular environment of different types of host cells has received much less attention. To address this issue, we report the transcriptome of Salmonella enterica serovar Typhimurium SL1344 within epithelial cells and show comparisons with Salmonella gene expression inside macrophages. We report that S. Typhimurium expresses a characteristic intracellular transcriptomic signature in response to the environments it encounters within different cell types. The signature involves the upregulation of the mgtBC, pstACS and iro genes for magnesium, phosphate and iron uptake, and Salmonella pathogenicity island 2 (SPI2). Surprisingly, in addition to SPI2, the invasion-associated SPI1 pathogenicity island and the genes involved in flagellar biosynthesis were expressed inside epithelial cells at later stages of the infection, while they were constantly downregulated in macrophage-like cells. To our knowledge, this is the first report of the simultaneous transcription of all three Type Three Secretion Systems (T3SS) within an intracellular Salmonella population. We discovered that S. Typhimurium strain SL1344 was strongly cytotoxic to epithelial cells after 6 h of infection and hypothesize that the time-dependent changes in Salmonella gene expression within epithelial cells reflects the bacterial response to host cells that have been injured by the infection process.
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Affiliation(s)
- I Hautefort
- Molecular Microbiology Group, Institute of Food Research, Norwich NR4 7UA, UK.
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The relationship of mucosal bacteria to duodenal histopathology, cytokine mRNA, and clinical disease activity in cats with inflammatory bowel disease. Vet Microbiol 2007; 128:178-93. [PMID: 18054447 DOI: 10.1016/j.vetmic.2007.10.014] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 10/08/2007] [Accepted: 10/10/2007] [Indexed: 12/27/2022]
Abstract
Feline inflammatory bowel disease (IBD) is the term applied to a group of poorly understood enteropathies that are considered a consequence of uncontrolled intestinal inflammation in response to a combination of elusive environmental, enteric microbial, and immunoregulatory factors in genetically susceptible cats. The present study sought to examine the relationship of mucosal bacteria to intestinal inflammation and clinical disease activity in cats with inflammatory bowel disease. Duodenal biopsies were collected from 27 cats: 17 undergoing diagnostic investigation of signs of gastrointestinal disease, and 10 healthy controls. Subjective duodenal histopathology ranged from normal (10), through mild (6), moderate (8), and severe (3) IBD. The number and spatial distribution of mucosal bacteria was determined by fluorescence in situ hybridization with probes to 16S rDNA. Mucosal inflammation was evaluated by objective histopathology and cytokine profiles of duodenal biopsies. The number of mucosa-associated Enterobacteriaceae was higher in cats with signs of gastrointestinal disease than healthy cats (P<0.001). Total numbers of mucosal bacteria were strongly associated with changes in mucosal architecture (P<0.001) and the density of cellular infiltrates, particularly macrophages (P<0.002) and CD3(+)lymphocytes (P<0.05). The number of Enterobacteriaceae, E. coli, and Clostridium spp. correlated with abnormalities in mucosal architecture (principally atrophy and fusion), upregulation of cytokine mRNA (particularly IL-1, -8 and -12), and the number of clinical signs exhibited by the affected cats. These data establish that the density and composition of the mucosal flora is related to the presence and severity of intestinal inflammation in cats and suggest that mucosal bacteria are involved in the etiopathogenesis of feline IBD.
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Abstract
Salmonella species cause substantial morbidity, mortality and burden of disease globally. Infections with Salmonella species cause multiple clinical syndromes. Central to the pathophysiology of all human salmonelloses is the induction of a strong host innate immune/inflammatory response. Whether this ultimately reflects an adaptive advantage to the host or pathogen is not clear. However, it is evident that both the host and pathogen have evolved mechanisms of triggering host responses that are detrimental to the other. In this review, we explore some of the host and pathogenic mechanisms mobilized in the two predominant clinical syndromes associated with infection with Salmonella enterica species: enterocolitis and typhoid.
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Affiliation(s)
- Bryan Coburn
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
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Xicohtencatl-Cortés J, Lyons S, Chaparro AP, Hernández DR, Saldaña Z, Ledesma MA, Rendón MA, Gewirtz AT, Klose KE, Girón JA. Identification of proinflammatory flagellin proteins in supernatants of Vibrio cholerae O1 by proteomics analysis. Mol Cell Proteomics 2006; 5:2374-83. [PMID: 16998199 DOI: 10.1074/mcp.m600228-mcp200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The genome of Vibrio cholerae contains five flagellin genes that encode proteins (FlaA-E) of 39-41 kDa with 61-82% identity among them. Although the existing live oral attenuated vaccine strains against cholera are protective in humans, there is an intrinsic residual cytotoxic and inflammatory component associated with these candidate vaccine strains. Bacterial flagellins are known to be potent inducers of proinflammatory molecules via activation of Toll-like receptor 5. Here we found that purified flagella from wild type V. cholerae 395 induced significant release of interleukin (IL)-8 from cultured HT-29 human colonic epithelial cells. Furthermore we found that filtered supernatants of KKV90, a DeltaflaA isogenic strain unable to produce flagella, were still able to activate production of IL-8 albeit to significantly lower levels than the wild type, suggesting that other activators of proinflammatory molecules were still present in these supernatants. A comparative proteomics analysis of secreted proteins of V. cholerae 395 and KKV90 identified additional proteins with potential to induce IL-8 release in HT-29 cells. Secreted proteins in the range of 30-45 kDa identified by two-dimensional electrophoresis and mass spectrometry revealed the presence of two additional flagellins, FlaC and FlaD, that appeared to be secreted 3- and 6-fold more, respectively, in the mutant compared with the wild type. Double isogenic mutants flaAC and flaAD were unable to trigger IL-8 release from HT-29 cells. In sum, we have shown that purified flagella and secreted flagellin proteins (FlaC and FlaD) are inducers of IL-8 release from epithelial cells via Toll-like receptor 5. This observation may explain, in part, the observed reactogenicity of cholera vaccine strains in humans.
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Abstract
Salmonella enterica serovar Typhi causes typhoid fever, a serious life-threatening systemic infection. In mice, a similar disease is caused by Salmonella enterica serovar Typhimurium. During typhoid fever, soon after attachment to the mucosal surface of the gut, bacteria come into contact with the dendritic cells (DCs). The ability to sample antigens, process and present them to naïve and mature T cells, in the context of major histocompatibility complex molecules, makes DCs indispensable for mounting a specific and efficient immune response to invading pathogens. These bacteria, however, have evolved a number of mechanisms to interfere with or subvert DC functions. This review aims to describe how Salmonella clashes with dendritic cells at different stages of infection as well as the war strategies of these two opposing sides.
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Affiliation(s)
- Marta Biedzka-Sarek
- Department of Bacteriology and Immunology, Haartman Institute, 00014 University of Helsinki, Helsinki, Finland.
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32
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Wallis TS, Barrow PA. Salmonella Epidemiology and Pathogenesis in Food-Producing Animals. EcoSal Plus 2005; 1. [PMID: 26443521 DOI: 10.1128/ecosalplus.8.6.2.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Indexed: 06/05/2023]
Abstract
This review reviews the pathogenesis of different phases of Salmonella infections. The nature of Salmonella infections in several domesticated animal species is described to highlight differences in the epidemiology and pathogenesis of salmonellosis in different hosts. The biology of Salmonella serovar host specificity is discussed in the context of our current understanding of the molecular basis of pathogenesis and the potential impact of different virulence determinants on Salmonella natural history. The ability to colonize the intestine, as evidenced by the shedding of relatively large numbers of bacteria in the feces over a long period, is shared unequally by Salmonella serovars. Studies probing the molecular basis of Salmonella intestinal colonization have been carried out by screening random transposon mutant banks of serovar Typhimurium in a range of avian and mammalian species. It is becoming increasingly clear that Salmonella pathogenicity island 2 (SPI2) is a major virulence factor during infection of food-producing animals, including cattle and poultry. The prevalence of Salmonella serovars in domestic fowl varies in different countries and with time. Although chickens are the natural hosts of serovars Gallinarum and Pullorum, natural outbreaks caused by these serovars in turkeys, guinea fowl, and other avian species have been described. There are two possible explanations to account for the apparent host specificity of certain Salmonella serovars. Environmental factors may increase exposure of particular animal species to certain serovars. Alternatively, there are genetic differences between these serovars, which allow them to survive and/or grow in specific niches only found within ruminants or pigs.
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Affiliation(s)
- Timothy S Wallis
- Division of Microbiology, Institute for Animal Health, Compton Laboratory, Berkshire RG20 7NN, United Kingdom
| | - Paul A Barrow
- Division of Microbiology, Institute for Animal Health, Compton Laboratory, Berkshire RG20 7NN, United Kingdom
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Rhee SJ, Walker WA, Cherayil BJ. Developmentally regulated intestinal expression of IFN-gamma and its target genes and the age-specific response to enteric Salmonella infection. THE JOURNAL OF IMMUNOLOGY 2005; 175:1127-36. [PMID: 16002714 DOI: 10.4049/jimmunol.175.2.1127] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Young infants are highly susceptible to systemic dissemination of enteric pathogens such as Salmonella typhimurium when compared with older individuals. The mechanisms underlying this differential susceptibility have not been defined clearly. To better understand this phenomenon, we examined the responses of adult mice and preweaned pups to oral infection by S. typhimurium. We found clear age-specific differences, namely, an attenuated intestinal inflammatory response and a higher systemic bacterial burden in the pups compared with the adults. To elucidate the molecular basis for these differences, we obtained a microarray-based profile of gene expression in the small intestines of uninfected adult and preweaned animals. The results indicated a striking age-dependent increase in the intestinal expression of a number of IFN-gamma-regulated genes involved in antimicrobial defense. This finding was confirmed by real-time quantitative PCR, which also demonstrated an age-dependent increase in intestinal expression of IFN-gamma. The developmental up-regulation of the IFN-gamma-regulated genes was dependent on both IFN-gamma and a normal commensal microflora, as indicated by experiments in IFN-gamma-knockout mice and germfree mice, respectively. However, the increase in expression of IFN-gamma itself was independent of the commensal flora. The functional importance of IFN-gamma in the immunological maturation of the intestine was confirmed by the observation that the response of adult IFN-gamma-knockout animals to S. typhimurium infection resembled that of the wild-type pups. Our findings thus reveal a novel role for IFN-gamma in the developmental regulation of antimicrobial responses in the intestine.
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MESH Headings
- Adjuvants, Immunologic/biosynthesis
- Adjuvants, Immunologic/deficiency
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/physiology
- Aging/genetics
- Aging/immunology
- Animals
- Animals, Newborn
- Enteritis/genetics
- Enteritis/immunology
- Enteritis/microbiology
- Enteritis/pathology
- Gene Expression Regulation, Developmental/immunology
- Germ-Free Life
- Immunity, Innate/genetics
- Interferon-gamma/biosynthesis
- Interferon-gamma/deficiency
- Interferon-gamma/genetics
- Interferon-gamma/physiology
- Intestinal Mucosa/immunology
- Intestinal Mucosa/microbiology
- Intestinal Mucosa/pathology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/microbiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Salmonella Infections, Animal/genetics
- Salmonella Infections, Animal/immunology
- Salmonella Infections, Animal/microbiology
- Salmonella Infections, Animal/pathology
- Salmonella typhimurium/growth & development
- Salmonella typhimurium/immunology
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Affiliation(s)
- Sue J Rhee
- Mucosal Immunology Laboratory, Pediatric Gastroenterology and Nutrition Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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Shibahara T, Miyazaki K, Sato D, Matsui H, Yanaka A, Nakahara A, Tanaka N. Alteration of intestinal epithelial function by intraepithelial lymphocyte homing. J Gastroenterol 2005; 40:878-86. [PMID: 16211344 DOI: 10.1007/s00535-005-1631-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Accepted: 04/01/2005] [Indexed: 02/04/2023]
Abstract
BACKGROUND Intimate cross-talk may take place between intestinal epithelial cells and intraepithelial lymphocytes (IEL). The purpose of this study was to analyze the influence of lymphocyte migration into the epithelium on epithelial function, using an in vitro "IEL homing" model. METHODS Molecular expression on epithelial cells was analyzed by flow cytometry. The barrier function of the epithelial monolayer was assessed by transepithelial electrical resistance. Cytokine production was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS (1) IEL homing into the epithelia induced significant phenotypic changes in epithelial cells; upregulation of MHC class I, and II, intercellular adhesion molecule (ICAM)-1, and CD44. IEL-derived interferon-gamma (IFN-gamma) could partially account for this alteration, as a neutralizing antibody (Ab) against IFN-gamma inhibited the upregulation of these molecules, except for CD44. (2) A marked fall in transepithelial electrical resistance was observed 4 h after IEL homing started, and Ab against IFN-gamma slightly inhibited this fall in resistance. (3) The production of interleukin (IL)-8 and IFN-gamma inducible protein-10 (IP-10), but not transforming growth factor (TGF)-beta1 or tumor necrosis factor (TNF)-alpha, in the epithelial monolayer was markedly induced after IEL homing in a basolaterally polarized fashion. IEL-conditioned media also induced the production of these cytokines in epithelial cells, thus suggesting that IEL-derived soluble factor(s) induce epithelial chemokine production. CONCLUSIONS Under inflammatory conditions, IEL obviously interact with epithelial cells and upregulate adhesion molecules, alter barrier function, and enhance chemokine production. Because such alterations may increase epithelial permeability to luminal antigens or accelerate the migration of other inflammatory cells, our results suggest that IEL have a critical role in mucosal immunity.
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Affiliation(s)
- Takeshi Shibahara
- Department of Gastroenterology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan
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35
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Sha J, Fadl AA, Klimpel GR, Niesel DW, Popov VL, Chopra AK. The two murein lipoproteins of Salmonella enterica serovar Typhimurium contribute to the virulence of the organism. Infect Immun 2004; 72:3987-4003. [PMID: 15213144 PMCID: PMC427434 DOI: 10.1128/iai.72.7.3987-4003.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Septic shock due to Salmonella and other gram-negative enteric pathogens is a leading cause of death worldwide. The role of lipopolysaccharide in sepsis is well studied; however, the contribution of other bacterial outer membrane components, such as Braun (murein) lipoprotein (Lpp), is not well defined. The genome of Salmonella enterica serovar Typhimurium harbors two copies of the lipoprotein (lpp) gene. We constructed a serovar Typhimurium strain with deletions in both copies of the lpp gene (lpp1 and lpp2) by marker exchange mutagenesis. The integrity of the cell membrane and the secretion of the effector proteins through the type III secretion system were not affected in the lpp double-knockout mutant. Subsequently, the virulence potential of this mutant was examined in a cell culture system using T84 intestinal epithelial and RAW264.7 macrophage cell lines and a mouse model of salmonellosis. The lpp double-knockout mutant was defective in invading and inducing cytotoxic effects in T84 and RAW264.7 cells, although binding of the mutant to the host cell was not affected when compared to the wild-type (WT) serovar Typhimurium. The motility of the mutant was impaired, despite the finding that the number of flagella was similar in the lpp double knockout mutant and the WT serovar Typhimurium. Deletion in the lpp genes did not affect the intracellular survival and replication of Salmonella in macrophages and T84 cells. Induction of the proinflammatory cytokines tumor necrosis factor alpha and interleukin-8 (IL-8) was significantly reduced in macrophages and T84 cells infected with the lpp double-knockout mutant. The levels of IL-8 remained unaffected in T84 cells when infected with either live or heat-killed WT and lpp mutant, indicating that invasion was not required for IL-8 production and that Toll-like receptor 2 signaling might be affected in the Lpp double-knockout mutant. These effects of the Lpp protein could be restored by complementation of the isogenic mutant. The lpp double-knockout mutant was avirulent in mice, and animals infected with this mutant were protected from a lethal challenge dose of WT serovar Typhimurium. The severe combined immunodeficient mice, on the other hand, were susceptible to infection by the lpp double-knockout mutant. The serovar Typhimurium mutants from which only one of the lpp (lpp1 or lpp2) genes was deleted were also avirulent in mice. Taken together, our data indicated that Lpp specifically contributed to the virulence of the organism.
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Affiliation(s)
- J Sha
- Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1070, USA
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Shifflett DE, Bottone FG, Young KM, Moeser AJ, Jones SL, Blikslager AT. Neutrophils augment recovery of porcine ischemia-injured ileal mucosa by an IL-1beta- and COX-2-dependent mechanism. Am J Physiol Gastrointest Liver Physiol 2004; 287:G50-7. [PMID: 15016613 DOI: 10.1152/ajpgi.00076.2003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Polymorphonuclear neutrophils (PMNs) play a critical role in intestinal mucosal injury and repair. To study effects of PMNs on acutely injured mucosa, we applied PMNs isolated from circulation or peritoneal fluid from animals with chemically induced peritonitis to ischemia-injured porcine ileal mucosa. In preliminary experiments, PMNs enhanced recovery of transepithelial electrical resistance (TER), and this action was inhibited by pretreatment with the nonselective cyclooxygenase (COX) inhibitor indomethacin. Because COX-2 is upregulated by inflammatory mediators such as IL-1beta, which is released by PMNs, we postulated that PMNs enhance recovery of ischemia-injured mucosa by a pathway involving IL-1beta and COX-2. Application of 5 x 10(6) PMNs to the serosal surface of ischemia-injured mucosa significantly enhanced recovery of TER (P < 0.05), an effect that was inhibited by the selective COX-2 inhibitor NS-398 (5 microM) and by an IL-1beta receptor antagonist (0.1 mg/ml). Addition of 10 ng/ml IL-1beta to the serosal surface of injured tissues caused a significant increase in TER (P < 0.05) that was inhibited by pretreatment with NS-398. Western blot analysis of mucosal homogenates revealed dramatic upregulation of COX-2 in response to IL-1beta or peritoneal PMNs, and the latter was inhibited by an IL-1beta receptor antagonist. Real-time PCR revealed that increased mRNA COX-2 expression preceded increased COX-2 protein expression in response to IL-1beta. We concluded that PMNs augment recovery of TER in ischemia-injured ileal mucosa via IL-1beta-dependent upregulation of COX-2.
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Affiliation(s)
- Donnie E Shifflett
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, NC 27606, USA
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Erjefält JS, Uller L, Malm-Erjefält M, Persson CG. Rapid and efficient clearance of airway tissue granulocytes through transepithelial migration. Thorax 2004; 59:136-43. [PMID: 14760154 PMCID: PMC1746951 DOI: 10.1136/thorax.2003.004218] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Clearance of tissue granulocytes is central to the resolution of airway inflammation. To date the focus has been on apoptotic mechanisms of cell removal and little attention has been given to alternative processes. The present study explores transepithelial migration as a mechanism of cell clearance. METHOD Guinea pig tracheobronchial airways where eosinophils are constitutively present in the mucosal tissue were studied. A complex topical stimulus (allergen challenge) was applied and the fate of the eosinophils was determined by selective tracheobronchial lavage and histological examination of the tissue. RESULTS Within 10 minutes of the allergen challenge, massive migration of eosinophils into the airway lumen occurred together with a reduction in tissue eosinophil numbers. Cell clearance into the lumen continued at high speed and by 30 and 60 minutes the tissue eosinophilia had been reduced by 63% and 73%, respectively. The marked transepithelial migration (estimated maximal speed 35,000 cells/min x cm2 mucosal surface) took place ubiquitously between epithelial cells without affecting epithelial integrity as assessed by transmission and scanning electron microscopy. Eosinophil apoptosis was not detected but occasional cytolytic eosinophils occurred. CONCLUSION This study shows that luminal entry has a remarkably high capacity as a granulocyte elimination process. The data also suggest that an appropriate stimulus of transepithelial migration may be used therapeutically to increase the resolution of inflammatory conditions of airway tissues.
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Affiliation(s)
- J S Erjefält
- Department of Physiological Sciences, Lund University, Lund, Sweden.
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38
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Lin PW, Simon PO, Gewirtz AT, Neish AS, Ouellette AJ, Madara JL, Lencer WI. Paneth cell cryptdins act in vitro as apical paracrine regulators of the innate inflammatory response. J Biol Chem 2004; 279:19902-7. [PMID: 14990585 DOI: 10.1074/jbc.m311821200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Intestinal-specific antimicrobial alpha-defensins, termed cryptdins, are secreted into the intestinal lumen by mouse Paneth cells in response to microbial pathogens. Cryptdins kill microbes by forming pores in their limiting membranes. The cryptdin isoforms 2 and 3 also can form anion-conductive pores in eukaryotic cell membranes, thus affecting cell physiology. Here, we find that when applied to apical membranes of the human intestinal cell line T84, cryptdin 3 (Cr3) induces secretion of the proinflammatory cytokine interleukin 8 (IL-8) in a dose-dependent manner. The induction of IL-8 secretion is specific to the cryptdins that form channels in mammalian cell membranes because cryptdin 4, which does not form pores in T84 cells, does not induce IL-8 secretion. Cr3 induces inflammatory cytokine secretion by activating NF-kappaB and p38 mitogen-activated protein kinase in a Ca2+-dependent manner, but influx by extra-cellular Ca2+ is not involved. Unlike other known inflammatory agonists, signal transduction by Cr3 occurs slowly, suggesting a novel mechanism of action. These results show that selective cryptdins may amplify their roles in innate immunity by acting as novel paracrine agonists to coordinate an inflammatory response with the antimicrobial secretions of Paneth cells.
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Affiliation(s)
- Patricia W Lin
- Gastrointestinal Cell Biology Department, Combined Program in Pediatric Gastroenterology and Nutrition, Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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de Andrade DR, de Andrade Júnior DR. Typhoid fever as cellular microbiological model. Rev Inst Med Trop Sao Paulo 2003; 45:185-91. [PMID: 14502344 DOI: 10.1590/s0036-46652003000400002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The knowledge about typhoid fever pathogenesis is growing in the last years, mainly about the cellular and molecular phenomena that are responsible by clinical manifestations of this disease. In this article are discussed several recent discoveries, as follows: a) Bacterial type III protein secretion system; b) The five virulence genes of Salmonella spp. that encoding Sips (Salmonella invasion protein) A, B, C, D and E, which are capable of induce apoptosis in macrophages; c) The function of Toll R2 and Toll R4 receptors present in the macrophage surface (discovered in the Drosophila). The Toll family receptors are critical in the signalizing mediated by LPS in macrophages in association with LBP and CD14; d) The lines of immune defense between intestinal lumen and internal organs; e) The fundamental role of the endothelial cells in the inflammatory deviation from bloodstream into infected tissues by bacteria. In addition to above subjects, the authors comment the correlation between the clinical features of typhoid fever and the cellular and molecular phenomena of this disease, as well as the therapeutic consequences of this knowledge.
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Affiliation(s)
- Dahir Ramos de Andrade
- Laboratório de Investigação Médica, School of Medicine, University of São Paulo, São Paulo, SP, Brazil.
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40
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Zhang S, Adams LG, Nunes J, Khare S, Tsolis RM, Bäumler AJ. Secreted effector proteins of Salmonella enterica serotype typhimurium elicit host-specific chemokine profiles in animal models of typhoid fever and enterocolitis. Infect Immun 2003; 71:4795-803. [PMID: 12874363 PMCID: PMC166006 DOI: 10.1128/iai.71.8.4795-4803.2003] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Infection of bovine ligated loops with the Salmonella enterica serotype Typhimurium wild type but not a sipA sopABDE2 mutant resulted in fluid accumulation, polymorphonuclear cell infiltration, and expression of CXC chemokines, particularly GRO alpha. None of these sipA sopABDE2-dependent responses was observed in murine-ligated loops. The majority of GRO alpha transcripts localized to bovine intestinal epithelium. Thus, different disease outcomes between mice (i.e., no diarrhea) and calves (i.e., diarrhea) may be due to differences in sipA sopABDE2-dependent CXC chemokine gene expression in epithelial cells.
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Affiliation(s)
- Shuping Zhang
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843-4467, USA
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Criss AK, Casanova JE. Coordinate regulation of Salmonella enterica serovar Typhimurium invasion of epithelial cells by the Arp2/3 complex and Rho GTPases. Infect Immun 2003; 71:2885-91. [PMID: 12704163 PMCID: PMC153244 DOI: 10.1128/iai.71.5.2885-2891.2003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Salmonella enterica serovar Typhimurium can infect epithelial cells via the basolateral surface after breaching the intestinal epithelium, yet little is known about this process. Here, we show that actin polymerization driven by the Arp2/3 complex is critical to both basolateral and apical bacterial invasion of polarized MDCK cells. While there is also a dependence upon toxin B-sensitive Rho GTPases, none of the four GTPases known to be activated by S. enterica serovar Typhimurium SopE are individually required for basolateral internalization. These results underscore that the specific factors required for Salmonella invasion differ between membrane domains of polarized epithelia.
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Affiliation(s)
- Alison K Criss
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908-0732,USA
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Bétis F, Brest P, Hofman V, Guignot J, Kansau I, Rossi B, Servin A, Hofman P. Afa/Dr diffusely adhering Escherichia coli infection in T84 cell monolayers induces increased neutrophil transepithelial migration, which in turn promotes cytokine-dependent upregulation of decay-accelerating factor (CD55), the receptor for Afa/Dr adhesins. Infect Immun 2003; 71:1774-83. [PMID: 12654791 PMCID: PMC152057 DOI: 10.1128/iai.71.4.1774-1783.2003] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2002] [Revised: 10/23/2002] [Accepted: 01/03/2003] [Indexed: 01/19/2023] Open
Abstract
Ulcerative colitis and Crohn's disease are inflammatory bowel diseases thought to involve strains of Escherichia coli. We report here that two wild-type Afa/Dr diffusely adhering E. coli (DAEC) strains, C1845 and IH11128, which harbor the fimbrial F1845 adhesin and the Dr hemagglutinin, respectively, and the E. coli laboratory strain HB101, transformed with the pSSS1 plasmid to produce Afa/Dr F1845 adhesin, all induced interleukin-8 (IL-8) production and transepithelial migration of polymorphonuclear leukocytes (PMNL) in polarized monolayers of the human intestinal cell line T84 grown on semipermeable filters. We observed that after PMNL migration, expression of decay-accelerating factor (DAF, or CD55), the brush border-associated receptor for Afa/Dr adhesins, was strongly enhanced, increasing the adhesion of Afa/Dr DAEC bacteria. When examining the mechanism by which DAF expression was enhanced, we observed that the PMNL transepithelial migration induced epithelial synthesis of tumor necrosis factor alpha and IL-1beta, which in turn promoted the upregulation of DAF.
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Affiliation(s)
- Fréderic Bétis
- Unité INSERM 36, IFR 50, Faculté de Médecine, avenue de Valombrose, 06107 Nice Cédex 02, France
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Bertelsen LS, Paesold G, Eckmann L, Barrett KE. Salmonella infection induces a hypersecretory phenotype in human intestinal xenografts by inducing cyclooxygenase 2. Infect Immun 2003; 71:2102-9. [PMID: 12654832 PMCID: PMC152023 DOI: 10.1128/iai.71.4.2102-2109.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enteric Salmonella infection is accompanied by inflammation and diarrhea, and yet little is known about its effects on intestinal epithelial physiology. Since species differences limit the utility of animal tissues and cell lines lack relevant cell-cell interactions, we have used a human model of fetal intestine grown as xenografts in SCID mice. We investigated here the effects of Salmonella enterica serovar Typhimurium SL1344 on xenograft ion transport. Harvested xenografts were stripped of seromuscular layers by blunt dissection, infected with Salmonella, and mounted in Ussing chambers. Salmonella infection for 1 h increased baseline ion transport without altering tissue conductance or morphology. The increased transport was blocked by the cyclooxygenase inhibitor, indomethacin, or the specific Cox-2 inhibitor, NS-398. Further, xenografts infected for 2 h showed increased secretory responses to the calcium-dependent agonist, carbachol, and the cyclic AMP-dependent agonists prostaglandin E(2) (PGE(2)) and forskolin, which were blocked by indomethacin. Western blot experiments revealed that infection was accompanied by increased cyclooxygenase 2 (Cox-2) expression, with no change in Cox-1 levels. Immunoassay demonstrated basolateral PGE(2) release, which was inhibited by indomethacin. Histological examination of infected xenografts illustrated that upregulated Cox-2 expression was restricted to the epithelium and that little or no invasion of the tissue by Salmonella occurred for up to 2 h. In summary, Salmonella infection rapidly increases Cox-2 expression in human intestinal tissue, accounting for increased epithelial ion transport characteristic of infectious diarrhea.
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Affiliation(s)
- Lone S Bertelsen
- Division of Gastroenterology, Department of Medicine, UCSD School of Medicine, Medical Center, 200 W. Arbor Street, San Diego, CA 92103-8414, USA
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Berkes J, Viswanathan VK, Savkovic SD, Hecht G. Intestinal epithelial responses to enteric pathogens: effects on the tight junction barrier, ion transport, and inflammation. Gut 2003; 52:439-51. [PMID: 12584232 PMCID: PMC1773546 DOI: 10.1136/gut.52.3.439] [Citation(s) in RCA: 415] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The effects of pathogenic organisms on host intestinal epithelial cells are vast. Innumerable signalling pathways are triggered leading ultimately to drastic changes in physiological functions. Here, the ways in which enteric bacterial pathogens utilise and impact on the three major physiological functions of the intestinal epithelium are discussed: alterations in the structure and function of the tight junction barrier, induction of fluid and electrolyte secretion, and activation of the inflammatory cascade. This field of investigation, which was virtually non-existent a decade ago, has now exploded, thus rapidly expanding our understanding of bacterial pathogenesis. Through increased delineation of the ways in which microbes alter host physiology, we simultaneous gain insight into the normal regulatory mechanisms of the intestinal epithelium.
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Affiliation(s)
- J Berkes
- Section of Digestive Diseases and Nutrition, University of Illinois at Chicago and Chicago Veterans Administration Medical Center, West Side Division, Chicago, IL 60612, USA
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Abstract
Necrotizing enterocolitis (NEC) seems to result from the inflammatory response of an immature intestine. Human milk is protective against NEC via an unknown mechanism. We hypothesized that specific factors found in human milk would decrease stimulated IL-8 secretion in intestinal epithelial cells. HT29-cl19A and Caco2 cells were compared with the fetal human primary intestinal epithelial cell line H4 and temperature-sensitive conditionally immortalized fetal human intestinal (tsFHI) cells. Cells were pretreated with transforming growth factor-beta (TGF-beta), erythropoietin (Epo), IL-10, or epidermal growth factor (EGF) at physiologic concentrations before stimulation with tumor necrosis factor-alpha (TNF-alpha) or IL-1beta, and then IL-8 was measured by ELISA. The fetal cells produced significantly more IL-8 when stimulated by TNF-alpha or IL-1beta. There were also differences in the pattern of alteration of IL-8 secretion by human milk factors. In HT29-cl19A cells, IL-10 inhibited TNF-alpha-stimulated IL-8 secretion by 52%, and EGF increased secretion by 144%. In H4 cells, TGF-beta1 and Epo inhibited TNF-alpha-stimulated IL-8 secretion to control levels, and EGF increased secretion by 29%. IL-1beta-stimulated IL-8 secretion was inhibited 25% by TGF-beta1 in Caco2 cells and in H4 cells was inhibited by TGF-beta1, Epo, and TGF-beta2. TsFHI cells confirmed H4 cell results. Fetal human enterocytes have an exaggerated IL-8 secretion in response to TNF-alpha and IL-1beta. TGF-beta and Epo decrease this stimulated IL-8 secretion, which may partially explain the protective effect of human milk in NEC.
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Affiliation(s)
- Erika C Claud
- Developmental Gastroenterology Laboratory, Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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Pasmans F, Van Immerseel F, Van den Broeck W, Bottreau E, Velge P, Ducatelle R, Haesebrouck F. Interactions of Salmonella enterica subsp. enterica serovar Muenchen with intestinal explants of the turtle Trachemys scripta scripta. J Comp Pathol 2003; 128:119-26. [PMID: 12634088 DOI: 10.1053/jcpa.2002.0614] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Salmonella infections in reptiles, in contrast to those in birds and mammals, are limited to the intestinal tract. In this study, interactions of a strain of Salmonella enterica subsp. enterica serovar Muenchen (SEEM) with intestinal explants of the turtle Trachemys scripta scripta were examined by scanning electron microscopy (SEM). Adhesion and invasion in the chelonian intestinal explants at 30 degrees C and 37 degrees C were evaluated quantitatively. For purposes of comparison, the invasive capacity of SEEM in the continuous avian epithelial cell line DIV-1 at 30 degrees C and 37 degrees C was determined. Small numbers of M-like cells were found in the ileum of the turtles. The bacteria adhered mainly to the mucus of the intestinal explants. Only small numbers of salmonellae were associated with epithelial cells. Higher numbers of bacteria adhered at 30 degrees C than at 37 degrees C. Epithelial damage, embedding of bacteria in the epithelial surface and a ruffling-like process were noted only at 37 degrees C. Minimal numbers of salmonellae invaded the explants at 30 degrees C and 37 degrees C. Invasion of DIV-1 cells was greater at 37 degrees C than at 30 degrees C. The study suggested that the intestinal mucous layer provides an important site of colonization for salmonellae in the chelonian host and protects the underlying epithelial cells.
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Affiliation(s)
- F Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium
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Köhler H, McCormick BA, Walker WA. Bacterial-enterocyte crosstalk: cellular mechanisms in health and disease. J Pediatr Gastroenterol Nutr 2003; 36:175-85. [PMID: 12548051 DOI: 10.1097/00005176-200302000-00005] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Henrik Köhler
- Mucosal Immunology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital and Harvard Medical School, 114 16th Street, Charlestown, MA 02129, USA
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Smith KD, Ozinsky A. Toll-like receptor-5 and the innate immune response to bacterial flagellin. Curr Top Microbiol Immunol 2003; 270:93-108. [PMID: 12467246 DOI: 10.1007/978-3-642-59430-4_6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The innate immune system identifies the presence of infection by detecting structures that are unique to microbes and that are not expressed in the host. The bacterial flagellum (Latin, a whip) confers motility, on a wide range of bacterial species. Vertebrates, plants, and invertebrates all have evolved flagellar recognition systems that are activated by flagellin, the major component of the bacterial flagellar filament. In mammals, flagellin is recognized by Toll-like receptor-5 and activates defense responses both systemically and at epithelial surfaces. Here, we review the role for Toll-like receptor-5 in mediating the mammalian innate immune response to flagellin, and how this provides for defense against infections caused by many different species of flagellated bacteria.
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Affiliation(s)
- K D Smith
- Department of Pathology, University of Washington, Box 35610, 1959 NE Pacific Street, Seattle, WA 98195, USA
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Abstract
Infections with Salmonella serotypes are a major cause of food-borne diseases worldwide. Animal models other than the mouse have been employed for the study of nontyphoidal Salmonella infections because the murine model is not suitable for the study of Salmonella-induced diarrhea. The microbe has developed mechanisms to exploit the host cell machinery to its own purpose. Bacterial proteins delivered directly into the host cell cytosol cause cytoskeletal changes and interfere with host cell signaling pathways, which ultimately enhance disease manifestation. Recently, marked advances have been made in our understanding of the molecular interactions between Salmonella serotypes and their hosts. Here, we discuss the molecular basis of the pathogenesis of Salmonella-induced enteritis.
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Affiliation(s)
- R L Santos
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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Nadeau WJ, Pistole TG, McCormick BA. Polymorphonuclear leukocyte migration across model intestinal epithelia enhances Salmonella typhimurium killing via the epithelial derived cytokine, IL-6. Microbes Infect 2002; 4:1379-87. [PMID: 12475628 DOI: 10.1016/s1286-4579(02)00020-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The host response to Salmonella typhimurium involves movement of polymorphonuclear leukocytes (PMN) across the epithelium and into the intestinal lumen. Following their arrival in the lumen, the PMN attempt to combat bacterial infection by activating antimicrobial defenses such as granule release, oxidative burst, phagocytosis, and cell signaling. We sought to examine PMN-S. typhimurium interaction following PMN arrival in the lumenal compartment. Here, for the first time, we demonstrate that PMN that have transmigrated across model intestinal epithelia have an enhanced ability to kill S. typhimurium. Our data provide evidence to indicate that the extracellular release of the primary and secondary granules of PMN, myeloperoxidase and lactoferrin, respectively, is correlated with enhanced bacterial killing. Furthermore, epithelial cells, during PMN transmigration, release the cytokine IL-6. IL-6 is known to increase intracellular stores of Ca(2+), and we have determined that this epithelial released cytokine is not only responsible for priming the PMN to release their granules, but also stimulating the PMN to kill S. typhimurium. These results substantiate the pathway in which PMN transmigration activates the epithelial release of IL-6, which in turn increases intracellular Ca(2+) storage. Our results, herein, extend this pathway to include an enhanced PMN granule release and an enhanced killing of S. typhimurium.
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Affiliation(s)
- William J Nadeau
- Mucosal Immunology Laboratory, Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Harvard Medical School, 114 16th Street (114-3503), MA, Boston 02129, USA
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