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Jans M, Vereecke L. A guide to germ-free and gnotobiotic mouse technology to study health and disease. FEBS J 2024. [PMID: 38523409 DOI: 10.1111/febs.17124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/17/2024] [Accepted: 03/11/2024] [Indexed: 03/26/2024]
Abstract
The intestinal microbiota has major influence on human physiology and modulates health and disease. Complex host-microbe interactions regulate various homeostatic processes, including metabolism and immune function, while disturbances in microbiota composition (dysbiosis) are associated with a plethora of human diseases and are believed to modulate disease initiation, progression and therapy response. The vast complexity of the human microbiota and its metabolic output represents a great challenge in unraveling the molecular basis of host-microbe interactions in specific physiological contexts. To increase our understanding of these interactions, functional microbiota research using animal models in a reductionistic setting are essential. In the dynamic landscape of gut microbiota research, the use of germ-free and gnotobiotic mouse technology, in which causal disease-driving mechanisms can be dissected, represents a pivotal investigative tool for functional microbiota research in health and disease, in which causal disease-driving mechanisms can be dissected. A better understanding of the health-modulating functions of the microbiota opens perspectives for improved therapies in many diseases. In this review, we discuss practical considerations for the design and execution of germ-free and gnotobiotic experiments, including considerations around germ-free rederivation and housing conditions, route and timing of microbial administration, and dosing protocols. This comprehensive overview aims to provide researchers with valuable insights for improved experimental design in the field of functional microbiota research.
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Affiliation(s)
- Maude Jans
- VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Belgium
| | - Lars Vereecke
- VIB Center for Inflammation Research, Ghent, Belgium
- Department of Internal Medicine and Pediatrics, Ghent University, Belgium
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2
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Quantitative dose-response analysis untangles host bottlenecks to enteric infection. Nat Commun 2023; 14:456. [PMID: 36709326 PMCID: PMC9884216 DOI: 10.1038/s41467-023-36162-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/17/2023] [Indexed: 01/30/2023] Open
Abstract
Host bottlenecks prevent many infections before the onset of disease by eliminating invading pathogens. By monitoring the diversity of a barcoded population of the diarrhea causing bacterium Citrobacter rodentium during colonization of its natural host, mice, we determine the number of cells that found the infection by establishing a replicative niche. In female mice the size of the pathogen's founding population scales with dose and is controlled by a severe yet slow-acting bottleneck. Reducing stomach acid or changing host genotype modestly relaxes the bottleneck without breaking the fractional relationship between dose and founders. In contrast, disrupting the microbiota causes the founding population to no longer scale with the size of the inoculum and allows the pathogen to infect at almost any dose, indicating that the microbiota creates the dominant bottleneck. Further, in the absence of competition with the microbiota, the diversity of the pathogen population slowly contracts as the population is overtaken by bacteria having lost the critical virulence island, the locus of enterocyte effacement (LEE). Collectively, our findings reveal that the mechanisms of protection by colonization bottlenecks are reflected in and can be generally defined by the impact of dose on the pathogen's founding population.
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Herzog MKM, Cazzaniga M, Peters A, Shayya N, Beldi L, Hapfelmeier S, Heimesaat MM, Bereswill S, Frankel G, Gahan CG, Hardt WD. Mouse models for bacterial enteropathogen infections: insights into the role of colonization resistance. Gut Microbes 2023; 15:2172667. [PMID: 36794831 PMCID: PMC9980611 DOI: 10.1080/19490976.2023.2172667] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/18/2023] [Indexed: 02/17/2023] Open
Abstract
Globally, enteropathogenic bacteria are a major cause of morbidity and mortality.1-3 Campylobacter, Salmonella, Shiga-toxin-producing Escherichia coli, and Listeria are among the top five most commonly reported zoonotic pathogens in the European Union.4 However, not all individuals naturally exposed to enteropathogens go on to develop disease. This protection is attributable to colonization resistance (CR) conferred by the gut microbiota, as well as an array of physical, chemical, and immunological barriers that limit infection. Despite their importance for human health, a detailed understanding of gastrointestinal barriers to infection is lacking, and further research is required to investigate the mechanisms that underpin inter-individual differences in resistance to gastrointestinal infection. Here, we discuss the current mouse models available to study infections by non-typhoidal Salmonella strains, Citrobacter rodentium (as a model for enteropathogenic and enterohemorrhagic E. coli), Listeria monocytogenes, and Campylobacter jejuni. Clostridioides difficile is included as another important cause of enteric disease in which resistance is dependent upon CR. We outline which parameters of human infection are recapitulated in these mouse models, including the impact of CR, disease pathology, disease progression, and mucosal immune response. This will showcase common virulence strategies, highlight mechanistic differences, and help researchers from microbiology, infectiology, microbiome research, and mucosal immunology to select the optimal mouse model.
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Affiliation(s)
- Mathias K.-M. Herzog
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich, Switzerland
| | - Monica Cazzaniga
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | - Audrey Peters
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Nizar Shayya
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Luca Beldi
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | | | - Markus M. Heimesaat
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Stefan Bereswill
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Cormac G.M. Gahan
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
- School of Pharmacy, University College Cork, Cork, Ireland
| | - Wolf-Dietrich Hardt
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich, Switzerland
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4
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Perruzza L, Strati F, Raneri M, Li H, Gargari G, Rezzonico-Jost T, Palatella M, Kwee I, Morone D, Seehusen F, Sonego P, Donati C, Franceschi P, Macpherson AJ, Guglielmetti S, Greiff V, Grassi F. Apyrase-mediated amplification of secretory IgA promotes intestinal homeostasis. Cell Rep 2022; 40:111112. [PMID: 35858559 DOI: 10.1016/j.celrep.2022.111112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/15/2022] [Accepted: 06/28/2022] [Indexed: 11/25/2022] Open
Abstract
Secretory immunoglobulin A (SIgA) interaction with commensal bacteria conditions microbiota composition and function. However, mechanisms regulating reciprocal control of microbiota and SIgA are not defined. Bacteria-derived adenosine triphosphate (ATP) limits T follicular helper (Tfh) cells in the Peyer's patches (PPs) via P2X7 receptor (P2X7R) and thereby SIgA generation. Here we show that hydrolysis of extracellular ATP (eATP) by apyrase results in amplification of the SIgA repertoire. The enhanced breadth of SIgA in mice colonized with apyrase-releasing Escherichia coli influences topographical distribution of bacteria and expression of genes involved in metabolic versus immune functions in the intestinal epithelium. SIgA-mediated conditioning of bacteria and enterocyte function is reflected by differences in nutrient absorption in mice colonized with apyrase-expressing bacteria. Apyrase-induced SIgA improves intestinal homeostasis and attenuates barrier impairment and susceptibility to infection by enteric pathogens in antibiotic-induced dysbiosis. Therefore, amplification of SIgA by apyrase can be leveraged to restore intestinal fitness in dysbiotic conditions.
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Affiliation(s)
- Lisa Perruzza
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Francesco Strati
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Matteo Raneri
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Hai Li
- Maurice Müller Laboratories, Department of Biomedical Research, Universitätsklinik für Viszerale Chirurgie und Medizin, Inselspital, University of Bern, Bern 3010, Switzerland
| | - Giorgio Gargari
- Division of Food Microbiology and Bioprocesses, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Milan 20133, Italy
| | - Tanja Rezzonico-Jost
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Martina Palatella
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Ivo Kwee
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Diego Morone
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Frauke Seehusen
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Paolo Sonego
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (TN) 38098, Italy
| | - Claudio Donati
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (TN) 38098, Italy
| | - Pietro Franceschi
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (TN) 38098, Italy
| | - Andrew J Macpherson
- Maurice Müller Laboratories, Department of Biomedical Research, Universitätsklinik für Viszerale Chirurgie und Medizin, Inselspital, University of Bern, Bern 3010, Switzerland
| | - Simone Guglielmetti
- Division of Food Microbiology and Bioprocesses, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Milan 20133, Italy
| | - Victor Greiff
- Department of Immunology and Oslo University Hospital, University of Oslo, Oslo 0372, Norway
| | - Fabio Grassi
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona 6500, Switzerland.
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Protective and Anti-Inflammatory Effects of Protegrin-1 on Citrobacter rodentium Intestinal Infection in Mice. Int J Mol Sci 2021; 22:ijms22179494. [PMID: 34502403 PMCID: PMC8431371 DOI: 10.3390/ijms22179494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/27/2021] [Indexed: 12/11/2022] Open
Abstract
Infectious intestinal colitis, manifesting as intestinal inflammation, diarrhea, and epithelial barrier disruption, affects millions of humans worldwide and, without effective treatment, can result in death. In addition to this, the significant rise in antibiotic-resistant bacteria poses an urgent need for alternative anti-infection therapies for the treatment of intestinal disorders. Antimicrobial peptides (AMPs) are potential therapies that have broad-spectrum antimicrobial activity due to their (1) unique mode of action, (2) broad-spectrum antimicrobial activity, and (3) protective role in GI tract maintenance. Protegrin-1 (PG-1) is an AMP of pig origin that was previously shown to reduce the pathological effects of chemically induced digestive tract inflammation (colitis) and to modulate immune responses and tissue repair. This study aimed to extend these findings by investigating the protective effects of PG-1 on pathogen-induced colitis in an infection study over a 10-day experimental period. The oral administration of PG-1 reduced Citrobacter rodentium intestinal infection in mice as evidenced by reduced histopathologic change in the colon, prevention of body weight loss, milder clinical signs of disease, and more effective clearance of bacterial infection relative to challenged phosphate-buffered saline (PBS)-treated mice. Additionally, PG-1 treatment altered the expression of various inflammatory mediators during infection, which may act to resolve inflammation and re-establish intestinal homeostasis. PG-1 administered in its mature form was more effective relative to the pro-form (ProPG-1). To our knowledge, this is the first study demonstrating the protective effects of PG-1 on infectious colitis.
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6
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Liang Q, Vallance BA. What's for dinner? How Citrobacter rodentium's metabolism helps it thrive in the competitive gut. Curr Opin Microbiol 2021; 63:76-82. [PMID: 34243134 DOI: 10.1016/j.mib.2021.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 01/04/2023]
Abstract
Enteric bacterial infections impose a significant and global health burden on society, and their threat is increasing in concert with a rise in antibiotic resistance. There is thus a great need to quickly develop new antimicrobial treatments and interest is growing in targeting pathogen nutrition and metabolism. In this review, we highlight recent research on the metabolism of Citrobacter rodentium, a murine-specific relative of enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC). We focus on the mechanisms by which C. rodentium acquires nutrients as well as the distinct metabolic strategies that C. rodentium employs in varying spatiotemporal niches. We propose that identifying and targeting nutrients found essential for bacterial pathogenesis is an attractive anti-microbial approach in the new post-antibiotic era.
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Affiliation(s)
- Qiaochu Liang
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, BC Children's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
| | - Bruce A Vallance
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, BC Children's Hospital and University of British Columbia, Vancouver, British Columbia, Canada.
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7
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Uncoupling of invasive bacterial mucosal immunogenicity from pathogenicity. Nat Commun 2020; 11:1978. [PMID: 32332737 PMCID: PMC7181798 DOI: 10.1038/s41467-020-15891-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 03/30/2020] [Indexed: 11/17/2022] Open
Abstract
There is the notion that infection with a virulent intestinal pathogen induces generally stronger mucosal adaptive immunity than the exposure to an avirulent strain. Whether the associated mucosal inflammation is important or redundant for effective induction of immunity is, however, still unclear. Here we use a model of auxotrophic Salmonella infection in germ-free mice to show that live bacterial virulence factor-driven immunogenicity can be uncoupled from inflammatory pathogenicity. Although live auxotrophic Salmonella no longer causes inflammation, its mucosal virulence factors remain the main drivers of protective mucosal immunity; virulence factor-deficient, like killed, bacteria show reduced efficacy. Assessing the involvement of innate pathogen sensing mechanisms, we show MYD88/TRIF, Caspase-1/Caspase-11 inflammasome, and NOD1/NOD2 nodosome signaling to be individually redundant. In colonized animals we show that microbiota metabolite cross-feeding may recover intestinal luminal colonization but not pathogenicity. Consequent immunoglobulin A immunity and microbial niche competition synergistically protect against Salmonella wild-type infection. Virulent pathogens generally induce a stronger mucosal immunity than avirulent strains, but whether the associated inflammation is necessary for this is unclear. Here, using auxotrophic Salmonella enterica, the authors show that virulence factor function determines induction of protective IgA.
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8
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Twin-Arginine Translocation System Is Involved in Citrobacter rodentium Fitness in the Intestinal Tract. Infect Immun 2020; 88:IAI.00892-19. [PMID: 31818958 DOI: 10.1128/iai.00892-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 11/27/2019] [Indexed: 01/16/2023] Open
Abstract
The twin-arginine translocation (Tat) system is involved in not only a wide array of cellular processes but also pathogenesis in many bacterial pathogens; thus, this system is expected to become a novel therapeutic target to treat infections. To the best of our knowledge, involvement of the Tat system has not been reported in the gut infection caused by Citrobacter rodentium Here, we studied the role of Tat in C. rodentium gut infection, which resembles human infection with enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). A C. rodentium Tat loss-of-function mutant displayed prolonged gut colonization, which was explained by reduced inflammatory responses and, particularly, neutrophil infiltration. Further, the Tat mutant had colonization defects upon coinfection with the wild-type strain of C. rodentium The Tat mutant also became hypersensitive to bile acids, and an increase in fecal bile acids fostered C. rodentium clearance from the gut lumen. Finally, we show that the chain form of C. rodentium cells, induced by a Tat-dependent cell division defect, exhibits impaired resistance to bile acids. Our findings indicate that the Tat system is involved in gut colonization by C. rodentium, which is associated with neutrophil infiltration and resistance to bile acids. Interventions that target the Tat system, as well as luminal bile acids, might thus be promising therapeutic strategies to treat human EHEC and EPEC infections.
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9
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Woodward SE, Krekhno Z, Finlay BB. Here, there, and everywhere: How pathogenicEscherichia colisense and respond to gastrointestinal biogeography. Cell Microbiol 2019; 21:e13107. [DOI: 10.1111/cmi.13107] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Sarah E. Woodward
- Department of Microbiology and ImmunologyUniversity of British Columbia Vancouver British Columbia Canada
- Michael Smith LaboratoriesUniversity of British Columbia Vancouver British Columbia Canada
| | - Zakhar Krekhno
- Department of Microbiology and ImmunologyUniversity of British Columbia Vancouver British Columbia Canada
- Michael Smith LaboratoriesUniversity of British Columbia Vancouver British Columbia Canada
| | - B. Brett Finlay
- Department of Microbiology and ImmunologyUniversity of British Columbia Vancouver British Columbia Canada
- Michael Smith LaboratoriesUniversity of British Columbia Vancouver British Columbia Canada
- Department of Biochemistry and Molecular BiologyUniversity of British Columbia Vancouver British Columbia Canada
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10
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Saha P, Yeoh BS, Xiao X, Golonka RM, Singh V, Wang Y, Vijay-Kumar M. PAD4-dependent NETs generation are indispensable for intestinal clearance of Citrobacter rodentium. Mucosal Immunol 2019; 12:761-771. [PMID: 30710097 PMCID: PMC6519124 DOI: 10.1038/s41385-019-0139-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/07/2019] [Accepted: 01/16/2019] [Indexed: 02/04/2023]
Abstract
Peptidyl arginine deiminase-4 (PAD4) is indispensable for generation of neutrophil extracellular traps (NETs), which can provide antimicrobial effects during host innate immune response; however, the role of PAD4 against gastrointestinal infection is largely unknown. Herein, we challenged PAD4-deficient (Pad4-/-) mice and wild-type (WT) littermates with Citrobacter rodentium (CR), and investigated bacteria clearance and gut pathology. Luminal colonization of CR in Pad4-/- mice peaked between 11-14 days post-infection, whereas WT mice suppressed the infection by 14 days. We demonstrated that Pad4-/- mice were unable to form NETs, whereas WT mice showed increased NETs formation in the colon during infection. Pad4-/- mice showed aggravated CR-associated inflammation as indicated by elevated systemic and colonic pro-inflammatory markers. Histological analysis revealed that transmissible colonic hyperplasia, goblet cell depletion, and apoptotic cell death were more pronounced in the colon of CR-infected Pad4-/- mice. Treating WT mice with deoxyribonuclease I, which can disrupt NETs generation, recapitulated the exacerbated CR infection and gut pathology associated with the loss of PAD4. Administration of the PAD4 inhibitor, Cl-amidine also aggravated CR infection, but to a lesser extent. Taken together, our findings highlight the importance of PAD4 in the mucosal clearance of CR and in resolving gut-associated inflammation.
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Affiliation(s)
- Piu Saha
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA
| | - Beng San Yeoh
- Graduate Program in Immunology & Infectious Disease, The Pennsylvania State University, University Park, Philadelphia, PA, 16802, USA
| | - Xia Xiao
- Division of Nephrology, MGH, Harvard Medical School, Boston, MA, 02114, USA
| | - Rachel M Golonka
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA
| | - Vishal Singh
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA
| | - Yanming Wang
- College of Life Sciences & Medicine, Henan University, Kaifeng, 475004, China
| | - Matam Vijay-Kumar
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA.
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11
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Ramirez VT, Godinez DR, Brust-Mascher I, Nonnecke EB, Castillo PA, Gardner MB, Tu D, Sladek JA, Miller EN, Lebrilla CB, Bevins CL, Gareau MG, Reardon C. T-cell derived acetylcholine aids host defenses during enteric bacterial infection with Citrobacter rodentium. PLoS Pathog 2019; 15:e1007719. [PMID: 30973939 PMCID: PMC6478367 DOI: 10.1371/journal.ppat.1007719] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 04/23/2019] [Accepted: 03/20/2019] [Indexed: 12/14/2022] Open
Abstract
The regulation of mucosal immune function is critical to host protection from enteric pathogens but is incompletely understood. The nervous system and the neurotransmitter acetylcholine play an integral part in host defense against enteric bacterial pathogens. Here we report that acetylcholine producing-T-cells, as a non-neuronal source of ACh, were recruited to the colon during infection with the mouse pathogen Citrobacter rodentium. These ChAT+ T-cells did not exclusively belong to one Th subset and were able to produce IFNγ, IL-17A and IL-22. To interrogate the possible protective effect of acetylcholine released from these cells during enteric infection, T-cells were rendered deficient in their ability to produce acetylcholine through a conditional gene knockout approach. Significantly increased C. rodentium burden was observed in the colon from conditional KO (cKO) compared to WT mice at 10 days post-infection. This increased bacterial burden in cKO mice was associated with increased expression of the cytokines IL-1β, IL-6, and TNFα, but without significant changes in T-cell and ILC associated IL-17A, IL-22, and IFNγ, or epithelial expression of antimicrobial peptides, compared to WT mice. Despite the increased expression of pro-inflammatory cytokines during C. rodentium infection, inducible nitric oxide synthase (Nos2) expression was significantly reduced in intestinal epithelial cells of ChAT T-cell cKO mice 10 days post-infection. Additionally, a cholinergic agonist enhanced IFNγ-induced Nos2 expression in intestinal epithelial cell in vitro. These findings demonstrated that acetylcholine, produced by specialized T-cells that are recruited during C. rodentium infection, are a key mediator in host-microbe interactions and mucosal defenses.
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Affiliation(s)
- Valerie T. Ramirez
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
| | - Dayn R. Godinez
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
| | - Ingrid Brust-Mascher
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
| | - Eric B. Nonnecke
- Department of Microbiology & Immunology, UC Davis School of Medicine, UC Davis, Davis, California, United States of America
| | - Patricia A. Castillo
- Department of Microbiology & Immunology, UC Davis School of Medicine, UC Davis, Davis, California, United States of America
| | - Mariana Barboza Gardner
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
- Department of Chemistry, UC Davis, Davis, California, United States of America
| | - Diane Tu
- Department of Chemistry, UC Davis, Davis, California, United States of America
| | - Jessica A. Sladek
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
| | - Elaine N. Miller
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
| | - Carlito B. Lebrilla
- Department of Chemistry, UC Davis, Davis, California, United States of America
| | - Charles L. Bevins
- Department of Microbiology & Immunology, UC Davis School of Medicine, UC Davis, Davis, California, United States of America
| | - Melanie G. Gareau
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
| | - Colin Reardon
- Department, of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, UC Davis, Davis, California, United States of America
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12
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Cooperative Metabolic Adaptations in the Host Can Favor Asymptomatic Infection and Select for Attenuated Virulence in an Enteric Pathogen. Cell 2018; 175:146-158.e15. [PMID: 30100182 DOI: 10.1016/j.cell.2018.07.016] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/09/2018] [Accepted: 07/11/2018] [Indexed: 12/11/2022]
Abstract
Pathogen virulence exists on a continuum. The strategies that drive symptomatic or asymptomatic infections remain largely unknown. We took advantage of the concept of lethal dose 50 (LD50) to ask which component of individual non-genetic variation between hosts defines whether they survive or succumb to infection. Using the enteric pathogen Citrobacter, we found no difference in pathogen burdens between healthy and symptomatic populations. Iron metabolism-related genes were induced in asymptomatic hosts compared to symptomatic or naive mice. Dietary iron conferred complete protection without influencing pathogen burdens, even at 1000× the lethal dose of Citrobacter. Dietary iron induced insulin resistance, increasing glucose levels in the intestine that were necessary and sufficient to suppress pathogen virulence. A short course of dietary iron drove the selection of attenuated Citrobacter strains that can transmit and asymptomatically colonize naive hosts, demonstrating that environmental factors and cooperative metabolic strategies can drive conversion of pathogens toward commensalism.
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13
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Runte CS, Jain U, Getz LJ, Secord S, Kuwae A, Abe A, LeBlanc JJ, Stadnyk AW, Kaper JB, Hansen AM, Thomas NA. Tandem tyrosine phosphosites in the Enteropathogenic Escherichia coli chaperone CesT are required for differential type III effector translocation and virulence. Mol Microbiol 2018; 108:536-550. [PMID: 29509331 DOI: 10.1111/mmi.13948] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2018] [Indexed: 11/29/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) use a type 3 secretion system (T3SS) for injection of effectors into host cells and intestinal colonization. Here, we demonstrate that the multicargo chaperone CesT has two strictly conserved tyrosine phosphosites, Y152 and Y153 that regulate differential effector secretion in EPEC. Conservative substitution of both tyrosine residues to phenylalanine strongly attenuated EPEC type 3 effector injection into host cells, and limited Tir effector mediated intimate adherence during infection. EPEC expressing a CesT Y152F variant were deficient for NleA effector expression and exhibited significantly reduced translocation of NleA into host cells during infection. Other effectors were observed to be dependent on CesT Y152 for maximal translocation efficiency. Unexpectedly, EPEC expressing a CesT Y153F variant exhibited significantly enhanced effector translocation of many CesT-interacting effectors, further implicating phosphosites Y152 and Y153 in CesT functionality. A mouse infection model of intestinal disease using Citrobacter rodentium revealed that CesT tyrosine substitution variants displayed delayed colonization and were more rapidly cleared from the intestine. These data demonstrate genetically separable functions for tandem tyrosine phosphosites within CesT. Therefore, CesT via its C-terminal tyrosine phosphosites, has relevant roles beyond typical type III secretion chaperones that interact and stabilize effector proteins.
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Affiliation(s)
- Cameron S Runte
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Umang Jain
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Landon J Getz
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sabrina Secord
- Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Asaomi Kuwae
- Laboratory of Bacterial Infection, Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
| | - Akio Abe
- Laboratory of Bacterial Infection, Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
| | - Jason J LeBlanc
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Medicine, Division of Infectious Diseases, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Andrew W Stadnyk
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - James B Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Anne-Marie Hansen
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nikhil A Thomas
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Medicine, Division of Infectious Diseases, Dalhousie University, Halifax, Nova Scotia, Canada
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