1
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Beutler M, Eberl C, Garzetti D, Herp S, Münch P, Ring D, Dolowschiak T, Brugiroux S, Schiller P, Hussain S, Basic M, Bleich A, Stecher B. Contribution of bacterial and host factors to pathogen "blooming" in a gnotobiotic mouse model for Salmonella enterica serovar Typhimurium-induced enterocolitis. Infect Immun 2024; 92:e0031823. [PMID: 38189339 PMCID: PMC10863408 DOI: 10.1128/iai.00318-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 12/05/2023] [Indexed: 01/09/2024] Open
Abstract
Inflammation has a pronounced impact on the intestinal ecosystem by driving an expansion of facultative anaerobic bacteria at the cost of obligate anaerobic microbiota. This pathogen "blooming" is also a hallmark of enteric Salmonella enterica serovar Typhimurium (S. Tm) infection. Here, we analyzed the contribution of bacterial and host factors to S. Tm "blooming" in a gnotobiotic mouse model for S. Tm-induced enterocolitis. Mice colonized with the Oligo-Mouse-Microbiota (OMM12), a minimal bacterial community, develop fulminant colitis by day 4 after oral infection with wild-type S. Tm but not with an avirulent mutant. Inflammation leads to a pronounced reduction in overall intestinal bacterial loads, distinct microbial community shifts, and pathogen blooming (relative abundance >50%). S. Tm mutants attenuated in inducing gut inflammation generally elicit less pronounced microbiota shifts and reduction in total bacterial loads. In contrast, S. Tm mutants in nitrate respiration, salmochelin production, and ethanolamine utilization induced strong inflammation and S. Tm "blooming." Therefore, individual Salmonella-specific inflammation-fitness factors seem to be of minor importance for competition against this minimal microbiota in the inflamed gut. Finally, we show that antibody-mediated neutrophil depletion normalized gut microbiota loads but not intestinal inflammation or microbiota shifts. This suggests that neutrophils equally reduce pathogen and commensal bacterial loads in the inflamed gut.
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Affiliation(s)
- Markus Beutler
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Claudia Eberl
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Debora Garzetti
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Simone Herp
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Philipp Münch
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
- Computational Biology of Infection Research, Helmholtz Center for Infection Research, Braunschweig, Germany
- Braunschweig Integrated Center of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Diana Ring
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Tamas Dolowschiak
- Institute of Microbiology, D-BIOL, ETH Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zürich, Switzerland
| | - Sandrine Brugiroux
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Patrick Schiller
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Saib Hussain
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Marijana Basic
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - André Bleich
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - Bärbel Stecher
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
- German Center for Infection Research (DZIF), partner site LMU Munich, Munich, Germany
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2
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Fattinger SA, Maurer L, Geiser P, Bernard EM, Enz U, Ganguillet S, Gül E, Kroon S, Demarco B, Mack V, Furter M, Barthel M, Pelczar P, Shao F, Broz P, Sellin ME, Hardt WD. Gasdermin D is the only Gasdermin that provides protection against acute Salmonella gut infection in mice. Proc Natl Acad Sci U S A 2023; 120:e2315503120. [PMID: 37988464 PMCID: PMC10691232 DOI: 10.1073/pnas.2315503120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/05/2023] [Indexed: 11/23/2023] Open
Abstract
Gasdermins (GSDMs) share a common functional domain structure and are best known for their capacity to form membrane pores. These pores are hallmarks of a specific form of cell death called pyroptosis and mediate the secretion of pro-inflammatory cytokines such as interleukin 1β (IL1β) and interleukin 18 (IL18). Thereby, Gasdermins have been implicated in various immune responses against cancer and infectious diseases such as acute Salmonella Typhimurium (S.Tm) gut infection. However, to date, we lack a comprehensive functional assessment of the different Gasdermins (GSDMA-E) during S.Tm infection in vivo. Here, we used epithelium-specific ablation, bone marrow chimeras, and mouse lines lacking individual Gasdermins, combinations of Gasdermins or even all Gasdermins (GSDMA1-3C1-4DE) at once and performed littermate-controlled oral S.Tm infections in streptomycin-pretreated mice to investigate the impact of all murine Gasdermins. While GSDMA, C, and E appear dispensable, we show that GSDMD i) restricts S.Tm loads in the gut tissue and systemic organs, ii) controls gut inflammation kinetics, and iii) prevents epithelium disruption by 72 h of the infection. Full protection requires GSDMD expression by both bone-marrow-derived lamina propria cells and intestinal epithelial cells (IECs). In vivo experiments as well as 3D-, 2D-, and chimeric enteroid infections further show that infected IEC extrusion proceeds also without GSDMD, but that GSDMD controls the permeabilization and morphology of the extruding IECs, affects extrusion kinetics, and promotes overall mucosal barrier capacity. As such, this work identifies a unique multipronged role of GSDMD among the Gasdermins for mucosal tissue defense against a common enteric pathogen.
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Affiliation(s)
- Stefan A. Fattinger
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala75123, Sweden
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Luca Maurer
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Petra Geiser
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala75123, Sweden
| | - Elliott M. Bernard
- Department of Immunobiology, University of Lausanne, Epalinges1066, Switzerland
| | - Ursina Enz
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Suwannee Ganguillet
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Ersin Gül
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Sanne Kroon
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Benjamin Demarco
- Department of Immunobiology, University of Lausanne, Epalinges1066, Switzerland
| | - Vanessa Mack
- Department of Immunobiology, University of Lausanne, Epalinges1066, Switzerland
| | - Markus Furter
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Manja Barthel
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel4002, Switzerland
| | - Feng Shao
- National Institute of Biological Sciences, Beijing102206, China
| | - Petr Broz
- Department of Immunobiology, University of Lausanne, Epalinges1066, Switzerland
| | - Mikael E. Sellin
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala75123, Sweden
| | - Wolf-Dietrich Hardt
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich8093, Switzerland
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3
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Sah P, Zenewicz LA. Modulation of innate lymphoid cells by enteric bacterial pathogens. Front Immunol 2023; 14:1219072. [PMID: 37483638 PMCID: PMC10358831 DOI: 10.3389/fimmu.2023.1219072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
Innate lymphoid cells (ILCs) are key regulators of tissue homeostasis, inflammation, and immunity to infections. ILCs rapidly respond to environmental cues such as cytokines, microbiota and invading pathogens which regulate their function and phenotype. Even though ILCs are rare cells, they are enriched at barrier surfaces such as the gastrointestinal (GI) tract, and they are often critical to the host's immune response to eliminate pathogens. On the other side of host-pathogen interactions, pathogenic bacteria also have the means to modulate these immune responses. Manipulation or evasion of the immune cells is often to the pathogen's benefit and/or to the detriment of competing microbiota. In some instances, specific bacterial virulence factors or toxins have been implicated in how the pathogen modulates immunity. In this review, we discuss the recent progress made towards understanding the role of non-cytotoxic ILCs during enteric bacterial infections, how these pathogens can modulate the immune response, and the implications these have on developing new therapies to combat infection.
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Affiliation(s)
| | - Lauren A. Zenewicz
- Department of Microbiology and Immunology, College of Medicine, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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4
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Altered gastrointestinal tract structure and microbiome following cerebral malaria infection. Parasitol Res 2023; 122:789-799. [PMID: 36602586 DOI: 10.1007/s00436-022-07775-2] [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: 06/07/2022] [Accepted: 12/20/2022] [Indexed: 01/06/2023]
Abstract
Cerebral malaria (CM) is the most severe form of malaria with the highest mortality rate and can result in life-long neurological deficits and ongoing comorbidities. Factors contributing to severity of infection and development of CM are not fully elucidated. Recent studies have indicated a key role of the gut microbiome in a range of health conditions that affect the brain, but limited microbiome research has been conducted in the context of malaria. To address this knowledge gap, the impact of CM on the gut microbiome was investigated in mice. C57BL/6J mice were infected with Plasmodium berghei ANKA (PbA) parasites and compared to non-infected controls. Microbial DNA from faecal pellets collected daily for 6-days post-infection were extracted, and microbiome comparisons conducted using 16S rRNA profiling. We identified significant differences in the composition of bacterial communities between the infected and the non-infected groups, including a higher abundance of the genera Akkermansia, Alistipes and Alloprevotella in PbA-infected mice. Furthermore, intestinal samples were collected post-cull for morphological analysis. We determined that the caecal weight was significantly lower, and the small intestine was significantly longer in PbA-infected mice than in the non-infected controls. We concluded that changes in microbial community composition were primarily driven by the infection protocol and, to a lesser extent, by the time of infection. Our findings pave the way for a new area of research and novel intervention strategies to modulate the severity of cerebral malaria disease.
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5
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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: 8] [Impact Index Per Article: 8.0] [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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6
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ILCs-Crucial Players in Enteric Infectious Diseases. Int J Mol Sci 2022; 23:ijms232214200. [PMID: 36430676 PMCID: PMC9695539 DOI: 10.3390/ijms232214200] [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: 10/31/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022] Open
Abstract
Research of the last decade has remarkably increased our understanding of innate lymphoid cells (ILCs). ILCs, in analogy to T helper (Th) cells and their cytokine and transcription factor profile, are categorized into three distinct populations: ILC1s express the transcription factor T-bet and secrete IFNγ, ILC2s depend on the expression of GATA-3 and release IL-5 and IL-13, and ILC3s express RORγt and secrete IL-17 and IL-22. Noteworthy, ILCs maintain a level of plasticity, depending on exposed cytokines and environmental stimuli. Furthermore, ILCs are tissue resident cells primarily localized at common entry points for pathogens such as the gut-associated lymphoid tissue (GALT). They have the unique capacity to initiate rapid responses against pathogens, provoked by changes of the cytokine profile of the respective tissue. Moreover, they regulate tissue inflammation and homeostasis. In case of intracellular pathogens entering the mucosal tissue, ILC1s respond by secreting cytokines (e.g., IFNγ) to limit the pathogen spread. Upon infection with helminths, intestinal epithelial cells produce alarmins (e.g., IL-25) and activate ILC2s to secrete IL-13, which induces differentiation of intestinal stem cells into tuft and goblet cells, important for parasite expulsion. Additionally, during bacterial infection ILC3-derived IL-22 is required for bacterial clearance by regulating antimicrobial gene expression in epithelial cells. Thus, ILCs can limit infectious diseases via secretion of inflammatory mediators and interaction with other cell types. In this review, we will address the role of ILCs during enteric infectious diseases.
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7
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Murphy JM, Ngai L, Mortha A, Crome SQ. Tissue-Dependent Adaptations and Functions of Innate Lymphoid Cells. Front Immunol 2022; 13:836999. [PMID: 35359972 PMCID: PMC8960279 DOI: 10.3389/fimmu.2022.836999] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/11/2022] [Indexed: 12/21/2022] Open
Abstract
Tissue-resident immune cells reside in distinct niches across organs, where they contribute to tissue homeostasis and rapidly respond to perturbations in the local microenvironment. Innate lymphoid cells (ILCs) are a family of innate immune cells that regulate immune and tissue homeostasis. Across anatomical locations throughout the body, ILCs adopt tissue-specific fates, differing from circulating ILC populations. Adaptations of ILCs to microenvironmental changes have been documented in several inflammatory contexts, including obesity, asthma, and inflammatory bowel disease. While our understanding of ILC functions within tissues have predominantly been based on mouse studies, development of advanced single cell platforms to study tissue-resident ILCs in humans and emerging patient-based data is providing new insights into this lymphocyte family. Within this review, we discuss current concepts of ILC fate and function, exploring tissue-specific functions of ILCs and their contribution to health and disease across organ systems.
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Affiliation(s)
- Julia M Murphy
- Department of Immunology, University of Toronto, Toronto, ON, Canada.,Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada.,Ajmera Transplant Centre, University Health Network, Toronto, ON, Canada
| | - Louis Ngai
- Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Arthur Mortha
- Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Sarah Q Crome
- Department of Immunology, University of Toronto, Toronto, ON, Canada.,Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada.,Ajmera Transplant Centre, University Health Network, Toronto, ON, Canada
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8
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Gullicksrud JA, Sateriale A, Englies JB, Gibson A, Shaw S, Hutchins ZA, Martin L, Christian DA, Taylor GA, Yamamoto M, Beiting DP, Striepen B, Hunter CA. Enterocyte-innate lymphoid cell crosstalk drives early IFN-γ-mediated control of Cryptosporidium. Mucosal Immunol 2022; 15:362-372. [PMID: 34750455 PMCID: PMC8881313 DOI: 10.1038/s41385-021-00468-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 08/14/2021] [Accepted: 09/03/2021] [Indexed: 02/04/2023]
Abstract
The intestinal parasite, Cryptosporidium, is a major contributor to global child mortality and causes opportunistic infection in immune deficient individuals. Innate resistance to Cryptosporidium, which specifically invades enterocytes, is dependent on the production of IFN-γ, yet whether enterocytes contribute to parasite control is poorly understood. In this study, utilizing a mouse-adapted strain of C. parvum, we show that epithelial-derived IL-18 synergized with IL-12 to stimulate innate lymphoid cell (ILC) production of IFN-γ required for early parasite control. The loss of IFN-γ-mediated STAT1 signaling in enterocytes, but not dendritic cells or macrophages, antagonized early parasite control. Transcriptional profiling of enterocytes from infected mice identified an IFN-γ signature and enrichment of the anti-microbial effectors IDO, GBP, and IRG. Deletion experiments identified a role for Irgm1/m3 in parasite control. Thus, enterocytes promote ILC production of IFN-γ that acts on enterocytes to restrict the growth of Cryptosporidium.
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Affiliation(s)
- Jodi A. Gullicksrud
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - Adam Sateriale
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America.,Current: The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Julie B. Englies
- Department of Pathobiology, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348, United States of America
| | - Alexis Gibson
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - Sebastian Shaw
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - Zachary A. Hutchins
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America.,Current: Jill Robests Institute for Research in Inflammatory Bowel Disease, Weill Cornell Medicine, New York, NY 10021, United States of America
| | - Lindsay Martin
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - David A. Christian
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - Gregory A. Taylor
- Departments of Medicine; Molecular Genetics and Microbiology; and Immunology; and Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, United States of America,Geriatric Research, Education, and Clinical Center, Durham VA Health Care System, Durham, North Carolina, United States of America
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Daniel P. Beiting
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
| | - Christopher A. Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, United States of America
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9
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Cairo C, Webb TJ. Effective Barriers: The Role of NKT Cells and Innate Lymphoid Cells in the Gut. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:235-246. [PMID: 35017213 DOI: 10.4049/jimmunol.2100799] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/19/2021] [Indexed: 06/14/2023]
Abstract
The critical role of commensal microbiota in regulating the host immune response has been established. In addition, it is known that host-microbial interactions are bidirectional, and this interplay is tightly regulated to prevent chronic inflammatory disease. Although many studies have focused on the role of classic T cell subsets, unconventional lymphocytes such as NKT cells and innate lymphoid cells also contribute to the regulation of homeostasis at mucosal surfaces and influence the composition of the intestinal microbiota. In this review, we discuss the mechanisms involved in the cross-regulation between NKT cells, innate lymphoid cells, and the gut microbiota. Moreover, we highlight how disruptions in homeostasis can lead to immune-mediated disorders.
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Affiliation(s)
- Cristiana Cairo
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD;
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD
| | - Tonya J Webb
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD; and
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD
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10
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Stolzer I, Schickedanz L, Chiriac MT, López-Posadas R, Grassl GA, Mattner J, Wirtz S, Winner B, Neurath MF, Günther C. STAT1 coordinates intestinal epithelial cell death during gastrointestinal infection upstream of Caspase-8. Mucosal Immunol 2022; 15:130-142. [PMID: 34497340 PMCID: PMC8732278 DOI: 10.1038/s41385-021-00450-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 08/17/2021] [Accepted: 08/24/2021] [Indexed: 02/04/2023]
Abstract
Intestinal homeostasis and the maintenance of the intestinal epithelial barrier are essential components of host defense during gastrointestinal Salmonella Typhimurium infection. Both require a strict regulation of cell death. However, the molecular pathways regulating epithelial cell death have not been completely understood. Here, we elucidated the contribution of central mechanisms of regulated cell death and upstream regulatory components during gastrointestinal infection. Mice lacking Caspase-8 in the intestinal epithelium are highly sensitive towards bacterial induced enteritis and intestinal inflammation, resulting in an enhanced lethality of these mice. This phenotype was associated with an increased STAT1 activation during Salmonella infection. Cell death, barrier breakdown and systemic infection were abrogated by an additional deletion of STAT1 in Casp8ΔIEC mice. In the absence of epithelial STAT1, loss of epithelial cells was abolished which was accompanied by a reduced Caspase-8 activation. Mechanistically, we demonstrate that epithelial STAT1 acts upstream of Caspase-8-dependent as well as -independent cell death and thus might play a major role at the crossroad of several central cell death pathways in the intestinal epithelium. In summary, we uncovered that transcriptional control of STAT1 is an essential host response mechanism that is required for the maintenance of intestinal barrier function and host survival.
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Affiliation(s)
- Iris Stolzer
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Laura Schickedanz
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Mircea T. Chiriac
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Rocío López-Posadas
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Guntram A. Grassl
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research (DZIF), Hannover, Germany
| | - Jochen Mattner
- grid.5330.50000 0001 2107 3311Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Stefan Wirtz
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Beate Winner
- grid.411668.c0000 0000 9935 6525Department of Stem Cell Biology, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Center for Rare Diseases Erlangen (ZSEER), Universitätsklinikum Erlangen, Erlangen, Germany
| | - Markus F. Neurath
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Claudia Günther
- grid.411668.c0000 0000 9935 6525Department of Medicine 1, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany ,grid.411668.c0000 0000 9935 6525Deutsches Zentrum Immuntherapie DZI, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU), Erlangen, Germany
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11
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Korchagina AA, Koroleva E, Tumanov AV. Innate Lymphoid Cells in Response to Intracellular Pathogens: Protection Versus Immunopathology. Front Cell Infect Microbiol 2021; 11:775554. [PMID: 34938670 PMCID: PMC8685334 DOI: 10.3389/fcimb.2021.775554] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/03/2021] [Indexed: 12/23/2022] Open
Abstract
Innate lymphoid cells (ILCs) are a heterogeneous group of cytokine-producing lymphocytes which are predominantly located at mucosal barrier surfaces, such as skin, lungs, and gastrointestinal tract. ILCs contribute to tissue homeostasis, regulate microbiota-derived signals, and protect against mucosal pathogens. ILCs are classified into five major groups by their developmental origin and distinct cytokine production. A recently emerged intriguing feature of ILCs is their ability to alter their phenotype and function in response to changing local environmental cues such as pathogen invasion. Once the pathogen crosses host barriers, ILCs quickly activate cytokine production to limit the spread of the pathogen. However, the dysregulated ILC responses can lead to tissue inflammation and damage. Furthermore, the interplay between ILCs and other immune cell types shapes the outcome of the immune response. Recent studies highlighted the important role of ILCs for host defense against intracellular pathogens. Here, we review recent advances in understanding the mechanisms controlling protective and pathogenic ILC responses to intracellular pathogens. This knowledge can help develop new ILC-targeted strategies to control infectious diseases and immunopathology.
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Affiliation(s)
- Anna A Korchagina
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Ekaterina Koroleva
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Alexei V Tumanov
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
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12
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Elemam NM, Ramakrishnan RK, Hundt JE, Halwani R, Maghazachi AA, Hamid Q. Innate Lymphoid Cells and Natural Killer Cells in Bacterial Infections: Function, Dysregulation, and Therapeutic Targets. Front Cell Infect Microbiol 2021; 11:733564. [PMID: 34804991 PMCID: PMC8602108 DOI: 10.3389/fcimb.2021.733564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Infectious diseases represent one of the largest medical challenges worldwide. Bacterial infections, in particular, remain a pertinent health challenge and burden. Moreover, such infections increase over time due to the continuous use of various antibiotics without medical need, thus leading to several side effects and bacterial resistance. Our innate immune system represents our first line of defense against any foreign pathogens. This system comprises the innate lymphoid cells (ILCs), including natural killer (NK) cells that are critical players in establishing homeostasis and immunity against infections. ILCs are a group of functionally heterogenous but potent innate immune effector cells that constitute tissue-resident sentinels against intracellular and extracellular bacterial infections. Being a nascent subset of innate lymphocytes, their role in bacterial infections is not clearly understood. Furthermore, these pathogens have developed methods to evade the host immune system, and hence permit infection spread and tissue damage. In this review, we highlight the role of the different ILC populations in various bacterial infections and the possible ways of immune evasion. Additionally, potential immunotherapies to manipulate ILC responses will be briefly discussed.
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Affiliation(s)
- Noha Mousaad Elemam
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Rakhee K Ramakrishnan
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Jennifer E Hundt
- Lübeck Institute for Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Rabih Halwani
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Prince Abdullah Ben Khaled Celiac Disease Chair, Department of Pediatrics, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Azzam A Maghazachi
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Qutayba Hamid
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Meakins-Christie Laboratories, McGill University, Montreal, QC, Canada
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13
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Roy U, de Oliveira RS, Galvez EJC, Gronow A, Basic M, Perez LG, Gagliani N, Bleich A, Huber S, Strowig T. Induction of IL-22-Producing CD4+ T Cells by Segmented Filamentous Bacteria Independent of Classical Th17 Cells. Front Immunol 2021; 12:671331. [PMID: 34566952 PMCID: PMC8456099 DOI: 10.3389/fimmu.2021.671331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 08/11/2021] [Indexed: 01/13/2023] Open
Abstract
The intestinal microbiota modulates IL-22 production in the intestine, including the induction of IL-22-producing CD4+ T helper cells. Which specific bacteria are responsible for the induction of these cells is less well understood. Here, we demonstrate through the use of novel gnotobiotic knock-in reporter mice that segmented filamentous bacteria (SFB), which are known for their ability to induce Th17 cells, also induce distinct IL-17A negative CD4+ T cell populations in the intestine. A subset of these cells instead produces IL-22 upon restimulation ex vivo and also during enteric infections. Furthermore, they produce a distinct set of cytokines compared to Th17 cells including the differential expression of IL-17F and IFN-γ. Importantly, genetic models demonstrate that these cells, presumably Th22 cells, develop independently of intestinal Th17 cells. Together, our data identifies that besides Th17, SFB also induces CD4+ T cell populations, which serve as immediate source of IL-22 during intestinal inflammation.
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Affiliation(s)
- Urmi Roy
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Rômulo S. de Oliveira
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Eric J. C. Galvez
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Achim Gronow
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Marijana Basic
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Laura Garcia Perez
- I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nicola Gagliani
- I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andre Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Samuel Huber
- I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Till Strowig
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
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14
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Establishing causality in Salmonella-microbiota-host interaction: The use of gnotobiotic mouse models and synthetic microbial communities. Int J Med Microbiol 2021; 311:151484. [PMID: 33756190 DOI: 10.1016/j.ijmm.2021.151484] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/07/2021] [Accepted: 02/23/2021] [Indexed: 02/07/2023] Open
Abstract
Colonization resistance (CR), the ability to block infections by potentially harmful microbes, is a fundamental function of host-associated microbial communities and highly conserved between animals and humans. Environmental factors such as antibiotics and diet can disturb microbial community composition and thereby predispose to opportunistic infections. The most prominent is Clostridioides difficile, the causative agent of diarrhea and pseudomembranous colitis. In addition, the risk to succumb to infections with genuine human enteric pathogens like nontyphoidal Salmonella (NTS) is also increased by a low-diverse, diet or antibiotic-disrupted microbiota. Despite extensive microbial community profiling efforts, only a limited set of microorganisms have been causally linked with protection against enteric pathogens. Furthermore, it remains a challenge to predict colonization resistance from complex microbiome signatures due to context-dependent action of microorganisms. In the past decade, the study of NTS infection has led to the description of several fundamental principles of microbiota-host-pathogen interaction. In this review, I will give an overview on the current state of knowledge in this field and outline experimental approaches to gain functional insight to the role of specific microbes, functions and metabolites in Salmonella-microbiota-host interaction. In particular, I will highlight the value of mouse infection models, which, in combination with culture collections, synthetic communities and gnotobiotic models have become essential tools to screen for protective members of the microbiota and establishing causal relationship and mechanisms in infection research.
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15
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Stolzer I, Ruder B, Neurath MF, Günther C. Interferons at the crossroad of cell death pathways during gastrointestinal inflammation and infection. Int J Med Microbiol 2021; 311:151491. [PMID: 33662871 DOI: 10.1016/j.ijmm.2021.151491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/03/2021] [Accepted: 02/23/2021] [Indexed: 02/07/2023] Open
Abstract
Interferons (IFNs) are pleiotropic immune-modulatory cytokines that are well known for their essential role in host defense against viruses, bacteria, and other pathogenic microorganisms. They can exert both, protective or destructive functions depending on the microorganism, the targeted tissue and the cellular context. Interferon signaling results in the induction of IFN-stimulated genes (ISGs) influencing different cellular pathways including direct anti-viral/anti-bacterial response, immune-modulation or cell death. Multiple pathways leading to host cell death have been described, and it is becoming clear that depending on the cellular context, IFN-induced cell death can be beneficial for both: host and pathogen. Accordingly, activation or repression of corresponding signaling mechanisms occurs during various types of infection but is also an important pathway for gastrointestinal inflammation and tissue damage. In this review, we summarize the role of interferons at the crossroad of various cell death pathways in the gut during inflammation and infection.
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Affiliation(s)
- Iris Stolzer
- Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Barbara Ruder
- Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU), Erlangen, Germany
| | - Markus F Neurath
- Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU), Erlangen, Germany; Deutsches Zentrum Immuntherapie DZI, Friedrich-Alexander-Universität (FAU), Erlangen, Nürnberg, Germany
| | - Claudia Günther
- Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU), Erlangen, Germany.
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16
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Epithelium-autonomous NAIP/NLRC4 prevents TNF-driven inflammatory destruction of the gut epithelial barrier in Salmonella-infected mice. Mucosal Immunol 2021; 14:615-629. [PMID: 33731826 PMCID: PMC8075861 DOI: 10.1038/s41385-021-00381-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/26/2020] [Accepted: 01/19/2021] [Indexed: 02/04/2023]
Abstract
The gut epithelium is a critical protective barrier. Its NAIP/NLRC4 inflammasome senses infection by Gram-negative bacteria, including Salmonella Typhimurium (S.Tm) and promotes expulsion of infected enterocytes. During the first ~12-24 h, this reduces mucosal S.Tm loads at the price of moderate enteropathy. It remained unknown how this NAIP/NLRC4-dependent tradeoff would develop during subsequent infection stages. In NAIP/NLRC4-deficient mice, S.Tm elicited severe enteropathy within 72 h, characterized by elevated mucosal TNF (>20 pg/mg) production from bone marrow-derived cells, reduced regeneration, excessive enterocyte loss, and a collapse of the epithelial barrier. TNF-depleting antibodies prevented this destructive pathology. In hosts proficient for epithelial NAIP/NLRC4, a heterogeneous enterocyte death response with both apoptotic and pyroptotic features kept S.Tm loads persistently in check, thereby preventing this dire outcome altogether. Our results demonstrate that immediate and selective removal of infected enterocytes, by locally acting epithelium-autonomous NAIP/NLRC4, is required to avoid a TNF-driven inflammatory hyper-reaction that otherwise destroys the epithelial barrier.
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17
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Innate immune responses to Listeria in vivo. Curr Opin Microbiol 2020; 59:95-101. [PMID: 33307408 DOI: 10.1016/j.mib.2020.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023]
Abstract
Listeria monocytogenes (Lm) is a foodborne bacterial pathogen that causes listeriosis, a severe infection that manifests as bacteremia and meningo-encephalitis mostly in immunocompromised individuals, and maternal-fetal infection. A critical pathogenic determinant of Lm relies on its ability to actively cross the intestinal barrier, disseminate systemically and cross the blood-brain and placental barriers. Here we illustrate how Lm both evades innate immunity, favoring its dissemination in host tissues, and triggers innate immune defenses that participate to its control.
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18
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Fattinger SA, Sellin ME, Hardt WD. Epithelial inflammasomes in the defense against Salmonella gut infection. Curr Opin Microbiol 2020; 59:86-94. [PMID: 33128958 DOI: 10.1016/j.mib.2020.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 02/06/2023]
Abstract
The gut epithelium prevents bacterial access to the host's tissues and coordinates a number of mucosal defenses. Here, we review the function of epithelial inflammasomes in the infected host and focus on their role in defense against Salmonella Typhimurium. This pathogen employs flagella to swim towards the epithelium and a type III secretion system (TTSS) to dock and invade intestinal epithelial cells. Flagella and TTSS components are recognized by the canonical NAIP/NLRC4 inflammasome, while LPS activates the non-canonical Caspase-4/11 inflammasome. The relative contributions of these inflammasomes, the activated cell death pathways and the elicited mucosal defenses are subject to environmental control and appear to change along the infection trajectory. It will be an important future task to explain how this may enable defense against the challenges imposed by diverse bacterial enteropathogens.
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Affiliation(s)
- Stefan A Fattinger
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland; Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Mikael E Sellin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland.
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19
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Kreuzer M, Hardt WD. How Food Affects Colonization Resistance Against Enteropathogenic Bacteria. Annu Rev Microbiol 2020; 74:787-813. [DOI: 10.1146/annurev-micro-020420-013457] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Food has a major impact on all aspects of health. Recent data suggest that food composition can also affect susceptibility to infections by enteropathogenic bacteria. Here, we discuss how food may alter the microbiota as well as mucosal defenses and how this can affect infection. Salmonella Typhimurium diarrhea serves as a paradigm, and complementary evidence comes from other pathogens. We discuss the effects of food composition on colonization resistance, host defenses, and the infection process as well as the merits and limitations of mouse models and experimental foods, which are available to decipher the underlying mechanisms.
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Affiliation(s)
- Markus Kreuzer
- Institute of Microbiology, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
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20
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Engevik MA, Banks LD, Engevik KA, Chang-Graham AL, Perry JL, Hutchinson DS, Ajami NJ, Petrosino JF, Hyser JM. Rotavirus infection induces glycan availability to promote ileum-specific changes in the microbiome aiding rotavirus virulence. Gut Microbes 2020; 11:1324-1347. [PMID: 32404017 PMCID: PMC7524290 DOI: 10.1080/19490976.2020.1754714] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Multiple studies have identified changes within the gut microbiome in response to diarrheal-inducing bacterial pathogens. However, examination of the microbiome in response to viral pathogens remains understudied. Compounding this, many studies use fecal samples to assess microbiome composition; which may not accurately mirror changes within the small intestine, the primary site for most enteric virus infections. As a result, the functional significance of small intestinal microbiome shifts during infection is not well defined. To address these gaps, rotavirus-infected neonatal mice were examined for changes in bacterial community dynamics, host gene expression, and tissue recovery during infection. Profiling bacterial communities using 16S rRNA sequencing suggested significant and distinct changes in ileal communities in response to rotavirus infection, with no significant changes for other gastrointestinal (GI) compartments. At 1-d post-infection, we observed a loss in Lactobacillus species from the ileum, but an increase in Bacteroides and Akkermansia, both of which exhibit mucin-digesting capabilities. Concomitant with the bacterial community shifts, we observed a loss of mucin-filled goblet cells in the small intestine at d 1, with recovery occurring by d 3. Rotavirus infection of mucin-producing cell lines and human intestinal enteroids (HIEs) stimulated release of stored mucin granules, similar to in vivo findings. In vitro, incubation of mucins with Bacteroides or Akkermansia members resulted in significant glycan degradation, which altered the binding capacity of rotavirus in silico and in vitro. Taken together, these data suggest that the response to and recovery from rotavirus-diarrhea is unique between sub-compartments of the GI tract and may be influenced by mucin-degrading microbes.
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Affiliation(s)
- Melinda A. Engevik
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA,Department of Pathology, Texas Children’s Hospital, Houston, TX, USA
| | - Lori D. Banks
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Kristen A. Engevik
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Alexandra L. Chang-Graham
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Jacob L. Perry
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Diane S. Hutchinson
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Nadim J. Ajami
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Joseph F. Petrosino
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Joseph M. Hyser
- Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, Houston, TX, USA,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA,CONTACT Joseph M. Hyser 1 Baylor Plaza, HoustonTX77030, USA
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21
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Innate Lymphoid Cells: Important Regulators of Host-Bacteria Interaction for Border Defense. Microorganisms 2020; 8:microorganisms8091342. [PMID: 32887435 PMCID: PMC7563982 DOI: 10.3390/microorganisms8091342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Innate lymphoid cells (ILCs) are a recently discovered type of innate immune lymphocyte. They include three different groups classified by the nature of the transcription factors required for their development and by the cytokines they produce. ILCs mainly reside in tissues close to the mucosal barrier such as the respiratory and gastrointestinal tracts. Due to their close proximity to the mucosal surface, ILCs are exposed to a variety of both commensal and pathogenic bacteria. Under non-pathological conditions, ILCs have been shown to be important regulators for the maintenance of tissue homeostasis by mutual interactions with the microbiome. Besides these important functions at homeostasis, several studies have also provided emerging evidence that ILCs contribute to defense against pathogenic bacterial infection by responding rapidly to the pathogens as well as orchestrating other immune cells. In this review, we summarize recent advances in our understanding of the interactions of ILCs and bacteria, with special focus on the function of the different ILC subsets in bacterial infections.
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22
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Liu Y, Yu X, Zhao J, Zhang H, Zhai Q, Chen W. The role of MUC2 mucin in intestinal homeostasis and the impact of dietary components on MUC2 expression. Int J Biol Macromol 2020; 164:884-891. [PMID: 32707285 DOI: 10.1016/j.ijbiomac.2020.07.191] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/05/2020] [Accepted: 07/17/2020] [Indexed: 12/19/2022]
Abstract
MUC2 mucin is an important secretory protein found in the human gut. Recent studies indicated that MUC2 mucin plays a role in the protection of gut barrier, the regulation of microbiome homeostasis and the prevention of diseases. In this review, the physiological properties of MUC2 mucin and its interactions with the intestinal microbiome are firstly discussed. Its roles in intestinal diseases including inflammatory bowel disease, colorectal cancer and parasitic infections are concluded. We also reviewed dietary components known to have modulative effects on MUC2 mucin expression, such as polysaccharides, amino acids and polyphenols.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Xinjie Yu
- Hwa Chong Institution (College), 661 Bukit Timah Road, Singapore 269734, Singapore
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, China; Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, China; (Yangzhou) Institute of Food Biotechnology, Jiangnan University, Yangzhou 225004, China
| | - Qixiao Zhai
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Research Laboratory for Probiotics at Jiangnan University, Wuxi, Jiangsu 214122, China.
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, China; Beijing Innovation Center of Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 100048, China
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23
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Furter M, Sellin ME, Hansson GC, Hardt WD. Mucus Architecture and Near-Surface Swimming Affect Distinct Salmonella Typhimurium Infection Patterns along the Murine Intestinal Tract. Cell Rep 2020; 27:2665-2678.e3. [PMID: 31141690 PMCID: PMC6547020 DOI: 10.1016/j.celrep.2019.04.106] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 04/01/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022] Open
Abstract
Mucus separates gut-luminal microbes from the tissue. It is unclear how pathogens like Salmonella Typhimurium (S.Tm) can overcome this obstacle. Using live microscopy, we monitored S.Tm interactions with native murine gut explants and studied how mucus affects the infection. A dense inner mucus layer covers the distal colon tissue, limiting direct tissue access. S.Tm performs near-surface swimming on this mucus layer, which allows probing for colon mucus heterogeneities, but can also entrap the bacterium in the dense inner colon mucus layer. In the cecum, dense mucus fills only the bottom of the intestinal crypts, leaving the epithelium between crypts unshielded and prone to access by motile and non-motile bacteria alike. This explains why the cecum is highly infection permissive and represents the primary site of S.Tm enterocolitis in the streptomycin mouse model. Our findings highlight the importance of mucus in intestinal defense and homeostasis. Live imaging of Salmonella near-surface swimming on mouse colon inner mucus layer Colon inner mucus layer traversal requires mucus breaches and flagellar propulsion The mouse cecum lacks a continuous mucus layer, leaving epithelium tips uncovered Exposed cecum epithelium tips are a hotspot for Salmonella infection
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Affiliation(s)
- Markus Furter
- Institute for Microbiology, ETH Zürich, 8093 Zürich, Switzerland
| | - Mikael E Sellin
- Institute for Microbiology, ETH Zürich, 8093 Zürich, Switzerland
| | - Gunnar C Hansson
- Department of Medical Biochemistry, University of Gothenburg, 40530 Gothenburg, Sweden
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24
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Pian Y, Chai Q, Ren B, Wang Y, Lv M, Qiu J, Zhu M. Type 3 Innate Lymphoid Cells Direct Goblet Cell Differentiation via the LT-LTβR Pathway during Listeria Infection. THE JOURNAL OF IMMUNOLOGY 2020; 205:853-863. [PMID: 32591396 DOI: 10.4049/jimmunol.2000197] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022]
Abstract
As a specialized subset of intestinal epithelial cells (IECs), goblet cells (GCs) play an important role during the antibacterial response via mucin production. However, the regulatory mechanisms involved in GC differentiation and function during infection, particularly the role of immune cell-IEC cross-talk, remain largely unknown. In this study, using Villin∆Ltbr conditional knockout mice, we demonstrate that LTβR, expressed on IECs, is required for GC hyperplasia and mucin 2 (MUC2) expression during Listeria infection for host defense but not homeostatic maintenance in the naive state. Analysis of single gene-deficient mice revealed that the ligand lymphotoxin (LT), but not LIGHT, and type 3 innate lymphoid cells (ILC3s), but not conventional T cells, are required for MUC2-dependent Listeria control. Conditional deficiency of LT in ILC3s further confirmed the importance of LT signals derived from ILC3s. Lack of ILC3-derived LT or IEC-derived LTβR resulted in the defective expression of genes related to GC differentiation but was not correlated with IEC proliferation and cell death, which were found to be normal by Ki-67 and Annexin V staining. In addition, the alternative NF-κB signaling pathway (involving RelB) in IECs was found to be required for the expression of GC differentiation-related genes and Muc2 and required for the anti-Listeria response. Therefore, our data together suggest a previously unrecognized ILC3-IEC interaction and LT-LTβR-RelB signaling axis governing GC differentiation and function during Listeria infection for host defense.
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Affiliation(s)
- Yaya Pian
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Qian Chai
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China;
| | - Boyang Ren
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; and
| | - Yue Wang
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; and
| | - Mengjie Lv
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ju Qiu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai 200031, China
| | - Mingzhao Zhu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; .,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; and
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25
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Seo GY, Giles DA, Kronenberg M. The role of innate lymphoid cells in response to microbes at mucosal surfaces. Mucosal Immunol 2020; 13:399-412. [PMID: 32047273 PMCID: PMC7186215 DOI: 10.1038/s41385-020-0265-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 02/04/2023]
Abstract
Innate lymphoid cells (ILCs) are a lymphocyte population that is mostly resident at mucosal surfaces. They help to induce an appropriate immune response to the microbiome at homeostasis. In healthy people, the mucosal immune system works symbiotically with organisms that make up the microbiota. ILCs play a critical role in orchestrating this balance, as they can both influence and in turn be influenced by the microbiome. ILCs also are important regulators of the early response to infections by diverse types of pathogenic microbes at mucosal barriers. Their rapid responses initiate inflammatory programs, production of antimicrobial products and repair processes. This review will focus on the role of ILCs in response to the microbiota and to microbial infections of the lung and intestine.
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Affiliation(s)
- Goo-Young Seo
- Division of Developmental Immunology, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA, 92037, USA
| | - Daniel A Giles
- Division of Developmental Immunology, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA, 92037, USA
| | - Mitchell Kronenberg
- Division of Developmental Immunology, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA, 92037, USA,Division of Biology, University of California San Diego, La Jolla, CA 92037, USA,Correspondence:
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26
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Crowley SM, Han X, Allaire JM, Stahl M, Rauch I, Knodler LA, Vallance BA. Intestinal restriction of Salmonella Typhimurium requires caspase-1 and caspase-11 epithelial intrinsic inflammasomes. PLoS Pathog 2020; 16:e1008498. [PMID: 32282854 PMCID: PMC7179941 DOI: 10.1371/journal.ppat.1008498] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/23/2020] [Accepted: 03/25/2020] [Indexed: 12/22/2022] Open
Abstract
We investigated the role of the inflammasome effector caspases-1 and -11 during Salmonella enterica serovar Typhimurium infection of murine intestinal epithelial cells (IECs). Salmonella burdens were significantly greater in the intestines of caspase-1/11 deficient (Casp1/11−/−), Casp1−/− and Casp11−/− mice, as compared to wildtype mice. To determine if this reflected IEC-intrinsic inflammasomes, enteroid monolayers were derived and infected with Salmonella. Casp11−/− and wildtype monolayers responded similarly, whereas Casp1−/− and Casp1/11−/− monolayers carried significantly increased intracellular burdens, concomitant with marked decreases in IEC shedding and death. Pretreatment with IFN-γ to mimic inflammation increased caspase-11 levels and IEC death, and reduced Salmonella burdens in Casp1−/− monolayers, while high intracellular burdens and limited cell shedding persisted in Casp1/11−/− monolayers. Thus caspase-1 regulates inflammasome responses in IECs at baseline, while proinflammatory activation of IECs reveals a compensatory role for caspase-11. These results demonstrate the importance of IEC-intrinsic canonical and non-canonical inflammasomes in host defense against Salmonella. Intestinal epithelial cells (IECs) are located at the interface between the gut lumen and the mucosal immune system and form the first layer of defense against the invasive enteric pathogen Salmonella enterica serovar Typhimurium. To prevent Salmonella, and other pathogens from establishing a foothold in the gut, the host mobilizes the inflammasome to selectively eject infected/compromised IECs from the epithelial layer into the intestinal lumen. This involves the activation of the inflammatory caspases; caspase-1 and -11. The individual contributions of each caspase to intestinal host defense, as well as the importance of IEC-intrinsic inflammasomes have not been previously defined, due to the lack of Casp1−/− mice as well as appropriate IEC-intrinsic defense models. Here, we determined that both caspases contribute to controlling Salmonella pathogen burdens and IEC shedding in the mouse intestine. Caspase-1 appears to play a larger role at baseline since caspase-11 expression must be first induced through proinflammatory signalling. Our data also highlights that IEC-intrinsic caspase activation is sufficient for infection-induced cell shedding and that the intestinal epithelium is a key site for inflammasome-mediated immune defense.
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Affiliation(s)
- Shauna M Crowley
- Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Xiao Han
- Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Joannie M Allaire
- Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin Stahl
- Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Isabella Rauch
- Department of Medical Microbiology & Immunology, School of Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Leigh A Knodler
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Bruce A Vallance
- Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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27
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Azimi T, Zamirnasta M, Sani MA, Soltan Dallal MM, Nasser A. Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review. Infect Drug Resist 2020; 13:11-26. [PMID: 32021316 PMCID: PMC6954085 DOI: 10.2147/idr.s230604] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022] Open
Abstract
Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.
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Affiliation(s)
- Taher Azimi
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zamirnasta
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
| | - Mahmood Alizadeh Sani
- Food Safety and Hygiene Division, Environmental health Department, School of Public Health, Tehran University of medical sciences, Tehran, Iran.,Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahmad Nasser
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran.,Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Department of Medical Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran
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28
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The Interplay between Salmonella enterica Serovar Typhimurium and the Intestinal Mucosa during Oral Infection. Microbiol Spectr 2019; 7. [PMID: 30953432 DOI: 10.1128/microbiolspec.bai-0004-2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacterial infection results in a dynamic interplay between the pathogen and its host. The underlying interactions are multilayered, and the cellular responses are modulated by the local environment. The intestine is a particularly interesting tissue regarding host-pathogen interaction. It is densely colonized by commensal microbes and a portal of entry for ingested pathogens. This necessitates constant monitoring of microbial stimuli in order to maintain homeostasis during encounters with benign microbiota and to trigger immune defenses in response to bacterial pathogens. Homeostasis is maintained by physical barriers (the mucus layer and epithelium), chemical defenses (antimicrobial peptides), and innate immune responses (NLRC4 inflammasome), which keep the bacteria from reaching the sterile lamina propria. Intestinal pathogens represent potent experimental tools to probe these barriers and decipher how pathogens can circumvent them. The streptomycin mouse model of oral Salmonella enterica serovar Typhimurium infection provides a well-characterized, robust experimental system for such studies. Strikingly, each stage of the gut tissue infection poses a different set of challenges to the pathogen and requires tight control of virulence factor expression, host response modulation, and cooperation between phenotypic subpopulations. Therefore, successful infection of the intestinal tissue relies on a delicate and dynamic balance between responses of the pathogen and its host. These mechanisms can be deciphered to their full extent only in realistic in vivo infection models.
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29
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Waddell A, Vallance JE, Hummel A, Alenghat T, Rosen MJ. IL-33 Induces Murine Intestinal Goblet Cell Differentiation Indirectly via Innate Lymphoid Cell IL-13 Secretion. THE JOURNAL OF IMMUNOLOGY 2018; 202:598-607. [PMID: 30530480 DOI: 10.4049/jimmunol.1800292] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 11/06/2018] [Indexed: 12/19/2022]
Abstract
Regulation of the intestinal mucus layer by goblet cells is important for preventing inflammation and controlling infection. IL-33, a cytokine upregulated in inflammatory bowel disease and helminth infection, induces intestinal goblet cells, but the mechanism remains unclear. Enteroids are three-dimensional structures of primary small intestinal epithelial cells that contain all differentiated intestinal epithelial cell types. We developed an enteroid-immune cell coculture model to determine the mechanism through which IL-33 affects intestinal goblet cell differentiation. We report that IL-33 does not directly induce goblet cell differentiation in murine enteroids; however, IL-13, a cytokine induced by IL-33, markedly induces goblet cells and gene expression consistent with goblet cell differentiation. When enteroids are cocultured with CD90+ mesenteric lymph node cells from IL-33-treated mice, IL-33 then induces IL-13 secretion by group 2 innate lymphoid cells and enteroid gene expression consistent with goblet cell differentiation. In cocultures, IL-33-induced Muc2 expression is dependent on enteroid Il4ra expression, demonstrating a requirement for IL-13 signaling in epithelial cells. In vivo, IL-33-induced intestinal goblet cell hyperplasia is dependent on IL-13. These studies demonstrate that IL-33 induces intestinal goblet cell differentiation not through direct action on epithelial cells but indirectly through IL-13 production by goup 2 innate lymphoid cells.
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Affiliation(s)
- Amanda Waddell
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Jefferson E Vallance
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Amy Hummel
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Theresa Alenghat
- Center for Inflammation and Tolerance, Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; and.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Michael J Rosen
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; .,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229
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30
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Disson O, Blériot C, Jacob JM, Serafini N, Dulauroy S, Jouvion G, Fevre C, Gessain G, Thouvenot P, Eberl G, Di Santo JP, Peduto L, Lecuit M. Peyer's patch myeloid cells infection by Listeria signals through gp38 + stromal cells and locks intestinal villus invasion. J Exp Med 2018; 215:2936-2954. [PMID: 30355616 PMCID: PMC6219733 DOI: 10.1084/jem.20181210] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/05/2018] [Accepted: 09/28/2018] [Indexed: 12/12/2022] Open
Abstract
The foodborne pathogen Listeria monocytogenes (Lm) crosses the intestinal villus epithelium via goblet cells (GCs) upon the interaction of Lm surface protein InlA with its receptor E-cadherin. Here, we show that Lm infection accelerates intestinal villus epithelium renewal while decreasing the number of GCs expressing luminally accessible E-cadherin, thereby locking Lm portal of entry. This novel innate immune response to an enteropathogen is triggered by the infection of Peyer's patch CX3CR1+ cells and the ensuing production of IL-23. It requires STAT3 phosphorylation in epithelial cells in response to IL-22 and IL-11 expressed by lamina propria gp38+ stromal cells. Lm-induced IFN-γ signaling and STAT1 phosphorylation in epithelial cells is also critical for Lm-associated intestinal epithelium response. GC depletion also leads to a decrease in colon mucus barrier thickness, thereby increasing host susceptibility to colitis. This study unveils a novel innate immune response to an enteropathogen, which implicates gp38+ stromal cells and locks intestinal villus invasion, but favors colitis.
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Affiliation(s)
- Olivier Disson
- Institut Pasteur, Biology of Infection Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1117, Paris, France
| | - Camille Blériot
- Institut Pasteur, Biology of Infection Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1117, Paris, France
| | - Jean-Marie Jacob
- Institut Pasteur, Stroma, Inflammation and Tissue Repair Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1224, Paris, France
| | - Nicolas Serafini
- Institut Pasteur, Innate Immunity Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1223, Paris, France
| | - Sophie Dulauroy
- Institut National de la Santé et de la Recherche Médicale U1224, Paris, France.,Institut Pasteur, Microenvironnement and Immunity Unit, Paris, France
| | - Grégory Jouvion
- Institut Pasteur, Human Histopathology and Animal Models Unit, Paris, France
| | - Cindy Fevre
- Institut Pasteur, Biology of Infection Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1117, Paris, France
| | - Grégoire Gessain
- Institut Pasteur, Biology of Infection Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1117, Paris, France
| | - Pierre Thouvenot
- Institut Pasteur, Biology of Infection Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1117, Paris, France
| | - Gérard Eberl
- Institut National de la Santé et de la Recherche Médicale U1224, Paris, France.,Institut Pasteur, Microenvironnement and Immunity Unit, Paris, France
| | - James P Di Santo
- Institut Pasteur, Innate Immunity Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1223, Paris, France
| | - Lucie Peduto
- Institut Pasteur, Stroma, Inflammation and Tissue Repair Unit, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1224, Paris, France
| | - Marc Lecuit
- Institut Pasteur, Biology of Infection Unit, Paris, France .,Institut National de la Santé et de la Recherche Médicale U1117, Paris, France.,Paris Descartes University, Department of Infectious Diseases and Tropical Medicine, Necker-Enfants Malades University Hospital, APHP, Institut Imagine, Paris, France
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31
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The Intestinal Epithelium: Central Coordinator of Mucosal Immunity. Trends Immunol 2018; 39:677-696. [DOI: 10.1016/j.it.2018.04.002] [Citation(s) in RCA: 276] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/23/2018] [Accepted: 04/03/2018] [Indexed: 12/15/2022]
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32
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Allaire JM, Morampudi V, Crowley SM, Stahl M, Yu H, Bhullar K, Knodler LA, Bressler B, Jacobson K, Vallance BA. Frontline defenders: goblet cell mediators dictate host-microbe interactions in the intestinal tract during health and disease. Am J Physiol Gastrointest Liver Physiol 2018; 314:G360-G377. [PMID: 29122749 PMCID: PMC5899238 DOI: 10.1152/ajpgi.00181.2017] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Goblet cells (GCs) are the predominant secretory epithelial cells lining the luminal surface of the mammalian gastrointestinal (GI) tract. Best known for their apical release of mucin 2 (Muc2), which is critical for the formation of the intestinal mucus barrier, GCs have often been overlooked for their active contributions to intestinal protection and host defense. In part, this oversight reflects the limited tools available to study their function but also because GCs have long been viewed as relatively passive players in promoting intestinal homeostasis and host defense. In light of recent studies, this perspective has shifted, as current evidence suggests that Muc2 as well as other GC mediators are actively released into the lumen to defend the host when the GI tract is challenged by noxious stimuli. The ability of GCs to sense and respond to danger signals, such as bacterial pathogens, has recently been linked to inflammasome signaling, potentially intrinsic to the GCs themselves. Moreover, further work suggests that GCs release Muc2, as well as other mediators, to modulate the composition of the gut microbiome, leading to both the expansion as well as the depletion of specific gut microbes. This review will focus on the mechanisms by which GCs actively defend the host from noxious stimuli, as well as describe advanced technologies and new approaches by which their responses can be addressed. Taken together, we will highlight current insights into this understudied, yet critical, aspect of intestinal mucosal protection and its role in promoting gut defense and homeostasis.
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Affiliation(s)
- Joannie M. Allaire
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vijay Morampudi
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shauna M. Crowley
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin Stahl
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hongbing Yu
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kirandeep Bhullar
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Leigh A. Knodler
- 2Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, Washington
| | - Brian Bressler
- 3Division of Gastroenterology, Department of Medicine, St. Paul’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevan Jacobson
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bruce A. Vallance
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
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33
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Thiemann S, Smit N, Roy U, Lesker TR, Gálvez EJC, Helmecke J, Basic M, Bleich A, Goodman AL, Kalinke U, Flavell RA, Erhardt M, Strowig T. Enhancement of IFNγ Production by Distinct Commensals Ameliorates Salmonella-Induced Disease. Cell Host Microbe 2018; 21:682-694.e5. [PMID: 28618267 DOI: 10.1016/j.chom.2017.05.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 04/11/2017] [Accepted: 05/22/2017] [Indexed: 01/28/2023]
Abstract
The microbiota contributes to colonization resistance against invading pathogens by competing for metabolites, producing inhibitory substances, and priming protective immune responses. However, the specific commensal bacteria that promote host resistance and immune-mediated protection remain largely elusive. Using isogenic mouse lines with distinct microbiota profiles, we demonstrate that severity of disease induced by enteric Salmonella Typhimurium infection is strongly modulated by microbiota composition in individual lines. Transferring a restricted community of cultivable intestinal commensals from protected into susceptible mice decreases S. Typhimurium tissue colonization and consequently disease severity. This reduced tissue colonization, along with ameliorated weight loss and prolonged survival, depends on microbiota-enhanced IFNγ production, as IFNγ-deficient mice do not exhibit protective effects. Innate cells and CD4+ T cells increase in number and show high levels of IFNγ after transfer of the commensal community. Thus, distinct microbiota members prevent intestinal Salmonella infection by enhancing antibacterial IFNγ responses.
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Affiliation(s)
- Sophie Thiemann
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Nathiana Smit
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Urmi Roy
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Till Robin Lesker
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Eric J C Gálvez
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Julia Helmecke
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Marijana Basic
- Institute for Laboratory Animal Science, Hannover Medical School, 30625 Hannover, Germany
| | - Andre Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, 30625 Hannover, Germany
| | - Andrew L Goodman
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover Medical School and the Helmholtz Centre for Infection Research, 30625 Hannover, Germany
| | - Richard A Flavell
- Department of Immunobiology, Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Marc Erhardt
- Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Till Strowig
- Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
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34
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NF-κB/twist mediated regulation of colonic inflammation by lupeol in abating dextran sodium sulfate induced colitis in mice. J Funct Foods 2018. [DOI: 10.1016/j.jff.2017.12.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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35
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Regoli M, Bertelli E, Gulisano M, Nicoletti C. The Multifaceted Personality of Intestinal CX 3 CR1 + Macrophages. Trends Immunol 2017; 38:879-887. [DOI: 10.1016/j.it.2017.07.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 12/30/2022]
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36
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Zhang K, Griffiths G, Repnik U, Hornef M. Seeing is understanding: Salmonella's way to penetrate the intestinal epithelium. Int J Med Microbiol 2017; 308:97-106. [PMID: 28939439 DOI: 10.1016/j.ijmm.2017.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/06/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023] Open
Abstract
The molecular processes that govern host-microbial interaction illustrate not only the sophisticated and multifaceted mechanisms that protect the host from infection, but also the elaborated features of microbial pathogens that have evolved to overcome or evade the host's immune system. Here we focus on Salmonella that like other enteric pathogens must overcome the intestinal mucosal immune system, a surface constantly on alert and evolved to restrict the enteric microbiota. We discuss the initial step of Salmonella infection, the penetration of the intestinal epithelial barrier and the models used to study this fascinating aspect of microbial pathogenesis.
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Affiliation(s)
- Kaiyi Zhang
- Institute of Medical Microbiology, RWTH University Hospital Aachen, Aachen, Germany
| | | | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway.
| | - Mathias Hornef
- Institute of Medical Microbiology, RWTH University Hospital Aachen, Aachen, Germany.
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37
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Abstract
肠黏液屏障是覆盖在肠上皮表面的由黏蛋白构成的凝胶型网状结构. MUC2是黏蛋白的主要成分, 其特殊结构能保障黏液屏障的结构稳定性和抗性. 杯状细胞能通过基础及调节分泌途径生成黏蛋白来维持和更新肠黏液层, 肠道菌群也是黏液的组成、厚度及黏液屏障通透性功能形成的关键因素. 肠黏液屏障能防止腔内细菌接触上皮, 发挥抗感染作用, 调节肠道免疫与外来刺激之间的平衡. 而黏液屏障的结构和功能受损在感染性疾病、炎症性肠病、囊性纤维化、肿瘤等多种肠道疾病的发生发展中也起重要作用, 或许会成为疾病治疗的新靶点.
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Wotzka SY, Nguyen BD, Hardt WD. Salmonella Typhimurium Diarrhea Reveals Basic Principles of Enteropathogen Infection and Disease-Promoted DNA Exchange. Cell Host Microbe 2017; 21:443-454. [PMID: 28407482 DOI: 10.1016/j.chom.2017.03.009] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/17/2017] [Accepted: 03/24/2017] [Indexed: 12/18/2022]
Abstract
Despite decades of research, efficient therapies for most enteropathogenic bacteria are still lacking. In this review, we focus on Salmonella enterica Typhimurium (S. Typhimurium), a frequent cause of acute, self-limiting food-borne diarrhea and a model that has revealed key principles of enteropathogen infection. We review the steps of gut infection and the mucosal innate-immune defenses limiting pathogen burdens, and we discuss how inflammation boosts gut luminal S. Typhimurium growth. We also discuss how S. Typhimurium-induced inflammation accelerates the transfer of plasmids and phages, which may promote the transmission of antibiotic resistance and facilitate emergence of pathobionts and pathogens with enhanced virulence. The targeted manipulation of the microbiota and vaccination might offer strategies to prevent this evolution. As gut luminal microbes impact various aspects of the host's physiology, improved strategies for preventing enteropathogen infection and disease-inflicted DNA exchange may be of broad interest well beyond the acute infection.
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Affiliation(s)
- Sandra Y Wotzka
- Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland
| | - Bidong D Nguyen
- Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland
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39
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Innate lymphoid cells in autoimmunity: emerging regulators in rheumatic diseases. Nat Rev Rheumatol 2017; 13:164-173. [PMID: 28148916 DOI: 10.1038/nrrheum.2016.218] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Innate lymphoid cells (ILCs) are important in the regulation of barrier homeostasis. These cells do not express T cell receptors but share many functional similarities with T helper cells and cytotoxic CD8+ T lymphocytes. ILCs are divided into three groups, namely group 1 ILCs, group 2 ILCs and group 3 ILCs, based on the transcription factors they depend on for their development and function, and the cytokines they produce. Emerging data indicate that ILCs not only have protective functions but can also have detrimental effects when dysregulated, leading to chronic inflammation and autoimmune diseases, including asthma, inflammatory bowel disease, graft-versus-host disease, psoriasis, rheumatoid arthritis and atopic dermatitis. Elucidation of the cytokine pathways involved in various autoimmune diseases - and the identification of ILCs as potent producers of these cytokines - points towards a potential role for these cellular players in the pathophysiology of these diseases. In this Review we discuss the current knowledge of the role of ILCs in the pathogenesis of rheumatic and other autoimmune diseases.
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40
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Kim M, Kim CH. Colonization and effector functions of innate lymphoid cells in mucosal tissues. Microbes Infect 2016; 18:604-614. [PMID: 27365193 PMCID: PMC5050099 DOI: 10.1016/j.micinf.2016.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/11/2016] [Accepted: 06/13/2016] [Indexed: 02/07/2023]
Abstract
Innate lymphoid cells (ILCs) protect mucosal barrier tissues to fight infection and maintain tissue integrity. ILCs and their progenitors are developmentally programmed to migrate, differentiate and populate various mucosal tissues and associated lymphoid tissues. Functionally mature ILC subsets respond to diverse pathogens such as bacteria, viruses, fungi and parasites in subset-specific manners. In this review, we will discuss how ILCs populate mucosal tissues and regulate immune responses to distinct pathogens to protect the host and maintain tissue integrity.
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Affiliation(s)
- Myunghoo Kim
- Laboratory of Immunology and Hematopoiesis, Department of Comparative Pathobiology, Weldon School of Biomedical Engineering, Purdue Institute of Inflammation, Immunology and Infectious Diseases, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - Chang H Kim
- Laboratory of Immunology and Hematopoiesis, Department of Comparative Pathobiology, Weldon School of Biomedical Engineering, Purdue Institute of Inflammation, Immunology and Infectious Diseases, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA.
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41
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Dolowschiak T, Mueller AA, Pisan LJ, Feigelman R, Felmy B, Sellin ME, Namineni S, Nguyen BD, Wotzka SY, Heikenwalder M, von Mering C, Mueller C, Hardt WD. IFN-γ Hinders Recovery from Mucosal Inflammation during Antibiotic Therapy for Salmonella Gut Infection. Cell Host Microbe 2016; 20:238-49. [PMID: 27453483 DOI: 10.1016/j.chom.2016.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 05/08/2016] [Accepted: 06/14/2016] [Indexed: 12/30/2022]
Abstract
Salmonella Typhimurium (S.Tm) causes acute enteropathy resolving after 4-7 days. Strikingly, antibiotic therapy does not accelerate disease resolution. We screened for factors blocking remission using a S.Tm enterocolitis model. The antibiotic ciprofloxacin clears pathogen stool loads within 3-24 hr, while gut pathology resolves more slowly (ψ50: ∼48 hr, remission: 6-9 days). This delayed resolution is mediated by an interferon-γ (IFN-γ)-dependent response that is triggered during acute infection and continues throughout therapy. Specifically, IFN-γ production by mucosal T and NK cells retards disease resolution by maintaining signaling through the transcriptional regulator STAT1 and boosting expression of inflammatory mediators like IL-1β, TNF, and iNOS. Additionally, sustained IFN-γ fosters phagocyte accumulation and hampers antimicrobial defense mediated by IL-22 and the lectin REGIIIβ. These findings reveal a role for IFN-γ in delaying resolution of intestinal inflammation and may inform therapies for acute Salmonella enteropathy, chronic inflammatory bowel diseases, or disease resolution during antibiotic treatment.
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Affiliation(s)
| | | | | | - Rounak Feigelman
- Department of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Boas Felmy
- Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland
| | | | | | | | | | - Mathias Heikenwalder
- Institute of Virology, TU Munich, 81675 Munich, Germany; Division of Chronic Inflammation and Cancer, DKFZ, 69121 Heidelberg, Germany
| | - Christian von Mering
- Department of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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42
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Müller AA, Dolowschiak T, Sellin ME, Felmy B, Verbree C, Gadient S, Westermann AJ, Vogel J, LeibundGut-Landmann S, Hardt WD. An NK Cell Perforin Response Elicited via IL-18 Controls Mucosal Inflammation Kinetics during Salmonella Gut Infection. PLoS Pathog 2016; 12:e1005723. [PMID: 27341123 PMCID: PMC4920399 DOI: 10.1371/journal.ppat.1005723] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/03/2016] [Indexed: 01/26/2023] Open
Abstract
Salmonella Typhimurium (S.Tm) is a common cause of self-limiting diarrhea. The mucosal inflammation is thought to arise from a standoff between the pathogen's virulence factors and the host's mucosal innate immune defenses, particularly the mucosal NAIP/NLRC4 inflammasome. However, it had remained unclear how this switches the gut from homeostasis to inflammation. This was studied using the streptomycin mouse model. S.Tm infections in knockout mice, cytokine inhibition and –injection experiments revealed that caspase-1 (not -11) dependent IL-18 is pivotal for inducing acute inflammation. IL-18 boosted NK cell chemoattractants and enhanced the NK cells' migratory capacity, thus promoting mucosal accumulation of mature, activated NK cells. NK cell depletion and Prf-/- ablation (but not granulocyte-depletion or T-cell deficiency) delayed tissue inflammation. Our data suggest an NK cell perforin response as one limiting factor in mounting gut mucosal inflammation. Thus, IL-18-elicited NK cell perforin responses seem to be critical for coordinating mucosal inflammation during early infection, when S.Tm strongly relies on virulence factors detectable by the inflammasome. This may have broad relevance for mucosal defense against microbial pathogens. Salmonella Typhimurium is a common cause of foodborne diarrhea. The disease symptoms arise already a few hours after infection. However, it had remained unclear how the immune system can mount the responses eliciting the disease symptoms so quickly. Earlier work in a mouse model had shown that the gut epithelium expresses a sensor, called NAIP/NLRC4/caspase-1 inflammasome that can detect the pathogen and mount a defense by 12-18h p.i. However, it has remained uncharacterized how inflammasome sensing drives the initial gut inflammation. Here, we found that the caspase-1 inflammasome triggers the production of IL-18, a pro-inflammatory cytokine that appears essential for the early onset of inflammation. IL-18 is driving the accumulation of NK cells into the infected mucosa, via the upregulation of NK cell chemoattractants and by the stimulation of their migratory capacity. Mature NK cells seem to induce mucosal inflammation via a perforin-mediated cytotoxic response. These data suggest that the inflammasome/IL-18/NK cell axis is a driver of early mucosal inflammation via a perforin-dependent cytotoxic NK cell response. Future work will have to address, if this mechanism is equally potent in the human gut and may contribute to ramping up the host's response during the first hours of infection. This may have implications for other gut infections and might provide leads for developing therapies.
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Affiliation(s)
- Anna A. Müller
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | | | - Mikael E. Sellin
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
- Department of Cell and Molecular Biology, Microbiology, Uppsala University, Uppsala, Sweden
| | - Boas Felmy
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | | | - Sandra Gadient
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | | | - Jörg Vogel
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
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Brasseit J, Althaus-Steiner E, Faderl M, Dickgreber N, Saurer L, Genitsch V, Dolowschiak T, Li H, Finke D, Hardt WD, McCoy KD, Macpherson AJ, Corazza N, Noti M, Mueller C. CD4 T cells are required for both development and maintenance of disease in a new mouse model of reversible colitis. Mucosal Immunol 2016; 9:689-701. [PMID: 26376366 DOI: 10.1038/mi.2015.93] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 08/06/2015] [Indexed: 02/04/2023]
Abstract
Current therapies to treat inflammatory bowel diseases have limited efficacy, significant side effects, and often wane over time. Little is known about the cellular and molecular mechanisms operative in the process of mucosal healing from colitis. To study such events, we developed a new model of reversible colitis in which adoptive transfer of CD4(+)CD45RB(hi) T cells into Helicobacter typhlonius-colonized lymphopenic mice resulted in a rapid onset of colonic inflammation that was reversible through depletion of colitogenic T cells. Remission was associated with an improved clinical and histopathological score, reduced immune cell infiltration to the intestinal mucosa, altered intestinal gene expression profiles, regeneration of the colonic mucus layer, and the restoration of epithelial barrier integrity. Notably, colitogenic T cells were not only critical for induction of colitis but also for maintenance of disease. Depletion of colitogenic T cells resulted in a rapid drop in tumor necrosis factor α (TNFα) levels associated with reduced infiltration of inflammatory immune cells to sites of inflammation. Although neutralization of TNFα prevented the onset of colitis, anti-TNFα treatment of mice with established disease failed to resolve colonic inflammation. Collectively, this new model of reversible colitis provides an important research tool to study the dynamics of mucosal healing in chronic intestinal remitting-relapsing disorders.
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Affiliation(s)
- J Brasseit
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - E Althaus-Steiner
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - M Faderl
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - N Dickgreber
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - L Saurer
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - V Genitsch
- Division of Clinical Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - T Dolowschiak
- Institute of Microbiology, ETH Zürich, Zurich, Switzerland
| | - H Li
- Maurice E. Müller Laboratories, University Clinic for Visceral Surgery and Medicine, University of Bern, Bern, Switzerland
| | - D Finke
- Division of Developmental Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - W-D Hardt
- Institute of Microbiology, ETH Zürich, Zurich, Switzerland
| | - K D McCoy
- Maurice E. Müller Laboratories, University Clinic for Visceral Surgery and Medicine, University of Bern, Bern, Switzerland
| | - A J Macpherson
- Maurice E. Müller Laboratories, University Clinic for Visceral Surgery and Medicine, University of Bern, Bern, Switzerland
| | - N Corazza
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - M Noti
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - C Mueller
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
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44
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The Roles of Inflammation, Nutrient Availability and the Commensal Microbiota in Enteric Pathogen Infection. Microbiol Spectr 2016; 3. [PMID: 26185088 DOI: 10.1128/microbiolspec.mbp-0008-2014] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The healthy human intestine is colonized by as many as 1014 bacteria belonging to more than 500 different species forming a microbial ecosystem of unsurpassed diversity, termed the microbiota. The microbiota's various bacterial members engage in a physiological network of cooperation and competition within several layers of complexity. Within the last 10 years, technological progress in the field of next-generation sequencing technologies has tremendously advanced our understanding of the wide variety of physiological and pathological processes that are influenced by the commensal microbiota (1, 2). An increasing number of human disease conditions, such as inflammatory bowel diseases (IBD), type 2 diabetes, obesity, allergies and colorectal cancer are linked with altered microbiota composition (3). Moreover, a clearer picture is emerging of the composition of the human microbiota in healthy individuals, its variability over time and between different persons and how the microbiota is shaped by environmental factors (i.e., diet) and the host's genetic background (4). A general feature of a normal, healthy gut microbiota can generate conditions in the gut that disfavor colonization of enteric pathogens. This is termed colonization-resistance (CR). Upon disturbance of the microbiota, CR can be transiently disrupted, and pathogens can gain the opportunity to grow to high levels. This disruption can be caused by exposure to antibiotics (5, 6), changes in diet (7, 8), application of probiotics and drugs (9), and a variety of diseases (3). Breakdown of CR can boost colonization by intrinsic pathogens or increase susceptibility to infections (10). One consequence of pathogen expansion is the triggering of inflammatory host responses and pathogen-mediated disease. Interestingly, human enteric pathogens are part of a small group of bacterial families that belong to the Proteobacteria: the Enterobacteriaceae (E. coli, Yersinia spp., Salmonella spp., Shigella spp.), the Vibrionaceae (Vibrio cholerae) and the Campylobacteriaceae (Campylobacter spp.). In general, members of these families (be it commensals or pathogens) only constitute a minority of the intestinal microbiota. However, proteobacterial "blooms" are a characteristic trait of an abnormal microbiota such as in the course of antibiotic therapy, dietary changes or inflammation (11). It has become clear that the gut microbiota not only plays a major role in priming and regulating mucosal and systemic immunity, but that the immune system also contributes to host control over microbiota composition. These two ways of mutual communication between the microbiota and the immune system were coined as "outside-in" and "inside-out," respectively (12). The significance of those interactions for human health is particularly evident in Crohn's disease (CD) and Ulcerative Colitis (UC). The symptoms of these recurrent, chronic types of gut inflammation are caused by an excessive immune response against one's own commensal microbiota (13). It is assumed that deregulated immune responses can be caused by a genetic predisposition, leading to, for example, the impairment of intestinal barrier function or disruption of mucosal T-cell homeostasis. In CD or UC patients, an abnormally composed microbiota, referred to as "dysbiosis," is commonly observed (discussed later). This is often characterized by an increased relative abundance of facultative anaerobic bacteria (e.g., Enterobacteriaeceae, Bacilli) and, at the same time, depletion of obligate anaerobic bacteria of the classes Bacteroidia and Clostridia. So far, it is unclear whether dysbiosis is a cause or a consequence of inflammatory bowel disease (IBD). In fact, both scenarios are equally conceivable. Recent work suggests that inflammatory immune responses in the gut (both IBD and pathogen-induced) can alter the gut luminal milieu in a way that favors dysbiosis (14). In this chapter, I present a survey on our current state of understanding of the characteristics and mechanisms underlying gut inflammation-associated dysbiosis. The role of dysbiosis in enteric infections and human IBD is discussed. In addition, I will focus on competition of enteric pathogens and the gut microbiota in the inflamed gut and the role of dysbiotic microbiota alterations (e.g., "Enterobacterial blooms" (11)) for the evolution of pathogenicity.
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45
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Muzaki ARBM, Tetlak P, Sheng J, Loh SC, Setiagani YA, Poidinger M, Zolezzi F, Karjalainen K, Ruedl C. Intestinal CD103(+)CD11b(-) dendritic cells restrain colitis via IFN-γ-induced anti-inflammatory response in epithelial cells. Mucosal Immunol 2016; 9:336-51. [PMID: 26174764 PMCID: PMC4801902 DOI: 10.1038/mi.2015.64] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/15/2015] [Indexed: 02/04/2023]
Abstract
A crosstalk between commensals, gut immune cells, and colonic epithelia is required for a proper function of intestinal mucosal barrier. Here we investigated the importance of two distinct intestinal dendritic cell (DC) subsets in controlling intestinal inflammation. We show that Clec9A-diphtheria toxin receptor (DTR) mice after depletion of CD103(+)CD11b(-) DCs developed severe, low-dose dextran sodium sulfate (DSS)-induced colitis, whereas the lack of CD103(+)CD11b(+) DCs in Clec4a4-DTR mice did not exacerbate intestinal inflammation. The CD103(+)CD11b(-) DC subset has gained a functional specialization that able them to repress inflammation via several epithelial interferon-γ (IFN-γ)-induced proteins. Among others, we identified that epithelial IDO1 and interleukin-18-binding protein (IL-18bp) were strongly modulated by CD103(+)CD11b(-) DCs. Through its preferential property to express IL-12 and IL-15, this particular DC subset can induce lymphocytes in colonic lamina propria and in epithelia to secrete IFN-γ that then can trigger a reversible early anti-inflammatory response in intestinal epithelial cells.
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Affiliation(s)
- A R B M Muzaki
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - P Tetlak
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - J Sheng
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - S C Loh
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Y A Setiagani
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - M Poidinger
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore
| | - F Zolezzi
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore
| | - K Karjalainen
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - C Ruedl
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore,()
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46
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Characteristics of innate lymphoid cells (ILCs) and their role in immunological disorders (an update). Cell Immunol 2015; 298:66-76. [PMID: 26429626 DOI: 10.1016/j.cellimm.2015.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/04/2015] [Accepted: 09/15/2015] [Indexed: 02/05/2023]
Abstract
Innate lymphoid cells (ILCs) are a novel family of hematopoietic effectors and regulators of innate immunity. Although these cells are morphologically similar to B cells and T cells, however they do not express antigen receptors. ILCs seems to have emerging roles in innate immune responses against infectious or non-infectious microorganisms, protection of the epithelial barrier, lymphoid organogenesis and inflammation, tissue remodeling and regulating homeostasis of tissue stromal cells. In addition, it has recently been reported that ILCs have a crucial role in several disorders such as allergy and autoimmunity. Based on their phenotype and functions, ILCs are classified into three major groups called ILCs1, ILCs2, and ILCs3. Here we reviewed the most recent data concerning diverse ILC phenotypes, subclasses, functions in immune responses as well as in immune mediated disorders.
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47
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Tukler Henriksson J, Coursey TG, Corry DB, De Paiva CS, Pflugfelder SC. IL-13 Stimulates Proliferation and Expression of Mucin and Immunomodulatory Genes in Cultured Conjunctival Goblet Cells. Invest Ophthalmol Vis Sci 2015; 56:4186-97. [PMID: 26132778 PMCID: PMC4495812 DOI: 10.1167/iovs.14-15496] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 05/17/2015] [Indexed: 12/30/2022] Open
Abstract
PURPOSE To investigate the effects of IL-13 on goblet cell proliferation, differentiation, and expression of mucin and immunomodulatory genes. METHODS Explants were excised from the conjunctiva of young C57BL/6 mice. Cultures received 200 μL per week of either Keratinocyte media (KSFM) or KSFM supplemented with 10 ng/mL IL-13 and were incubated for 3 (D3), 7 (D7), or 14 (D14) days. Subsequently, cell proliferation was assessed or cultures were immunostained, collected for dot blot, or for reverse transcription (RT) and quantitative real-time PCR (qPCR) or for RT-PCR gene array. RESULTS The cultured conjunctival epithelium expressed goblet cell associated keratin 7 and mucins MUC5AC and MUC2 and when stimulated with IL-13 showed increased proliferation at D3 and D7 (P < 0.05) compared with control. MUC5AC expression was increased in the IL-13-treated group at D3 and D14 (P < 0.05). IL-13-treated cultures showed increased chemokine ligand 26 (CCL26), chloride channel calcium activated channel 3 (CLCA3), fas ligand (FasL), and Relm-β at D7. All conjunctival cultures expressed MUC2, and its expression was decreased at D3 (P < 0.05) and increased at D14 (P < 0.05) with IL-13 treatment. CONCLUSIONS This study demonstrated that conjunctival goblet cells are IL-13 responsive cells that produce factors known to maintain epithelial barrier, stimulate mucin production, and modulate immune response in nonocular mucosa when treated with IL-13. The functional significance of IL-13-stimulated factors remains to be determined.
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Affiliation(s)
- Johanna Tukler Henriksson
- Department of Ophthalmology and the Ocular Surface Center Baylor College of Medicine, Houston, Texas, United States
| | - Terry G. Coursey
- Department of Ophthalmology and the Ocular Surface Center Baylor College of Medicine, Houston, Texas, United States
| | - David B. Corry
- Departments of Medicine and Pathology & Immunology and the Biology of Inflammation Center, Baylor College of Medicine, Houston, Texas, United States
| | - Cintia S. De Paiva
- Department of Ophthalmology and the Ocular Surface Center Baylor College of Medicine, Houston, Texas, United States
| | - Stephen C. Pflugfelder
- Department of Ophthalmology and the Ocular Surface Center Baylor College of Medicine, Houston, Texas, United States
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48
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Eberl G, Colonna M, Di Santo JP, McKenzie ANJ. Innate lymphoid cells. Innate lymphoid cells: a new paradigm in immunology. Science 2015; 348:aaa6566. [PMID: 25999512 DOI: 10.1126/science.aaa6566] [Citation(s) in RCA: 579] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Innate lymphoid cells (ILCs) are a growing family of immune cells that mirror the phenotypes and functions of T cells. However, in contrast to T cells, ILCs do not express acquired antigen receptors or undergo clonal selection and expansion when stimulated. Instead, ILCs react promptly to signals from infected or injured tissues and produce an array of secreted proteins termed cytokines that direct the developing immune response into one that is adapted to the original insult. The complex cross-talk between microenvironment, ILCs, and adaptive immunity remains to be fully deciphered. Only by understanding these complex regulatory networks can the power of ILCs be controlled or unleashed in order to regulate or enhance immune responses in disease prevention and therapy.
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Affiliation(s)
- Gérard Eberl
- Institut Pasteur, Microenvironment and Immunity Unit, 75724 Paris, France.
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - James P Di Santo
- Institut Pasteur, Innate Immunity Unit, INSERM U668, 75724 Paris, France
| | - Andrew N J McKenzie
- Medical Research Council (MRC) Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
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49
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Mucosal physical and chemical innate barriers: Lessons from microbial evasion strategies. Semin Immunol 2015; 27:111-8. [PMID: 25936225 DOI: 10.1016/j.smim.2015.03.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/13/2015] [Indexed: 12/24/2022]
Abstract
The innate immune system has evolved since millions of years under a selective pressure. Among the different host mechanisms selected and conserved as a first line of defense, the gastrointestinal mucus layer constitutes an efficient physical and chemical barrier against invading microbes. Mucin glycoproteins and antimicrobial peptides are the major components of the mucus barrier, and evidences prove that they form an effective protection against most microbes. However, successful pathogens have evolved evasion strategies to circumvent this defense barrier. Here, we discuss the interactions between pathogens, mucins, and antimicrobial peptides, and the mechanisms that pathogens have developed to evade the innate defense systems of the intestinal mucosal barrier.
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50
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Faderl M, Noti M, Corazza N, Mueller C. Keeping bugs in check: The mucus layer as a critical component in maintaining intestinal homeostasis. IUBMB Life 2015; 67:275-85. [PMID: 25914114 DOI: 10.1002/iub.1374] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 03/04/2015] [Indexed: 12/19/2022]
Abstract
In the mammalian gastrointestinal tract the close vicinity of abundant immune effector cells and trillions of commensal microbes requires sophisticated barrier and regulatory mechanisms to maintain vital host-microbial interactions and tissue homeostasis. During co-evolution of the host and its intestinal microbiota a protective multilayered barrier system was established to segregate the luminal microbes from the intestinal mucosa with its potent immune effector cells, limit bacterial translocation into host tissues to prevent tissue damage, while ensuring the vital functions of the intestinal mucosa and the luminal gut microbiota. In the present review we will focus on the different layers of protection in the intestinal tract that allow the successful mutualism between the microbiota and the potent effector cells of the intestinal innate and adaptive immune system. In particular, we will review some of the recent findings on the vital functions of the mucus layer and its site-specific adaptations to the changing quantities and complexities of the microbiota along the (gastro-) intestinal tract. Understanding the regulatory pathways that control the establishment of the mucus layer, but also its degradation during intestinal inflammation may be critical for designing novel strategies aimed at maintaining local tissue homeostasis and supporting remission from relapsing intestinal inflammation in patients with inflammatory bowel diseases.
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Affiliation(s)
- Martin Faderl
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Mario Noti
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Nadia Corazza
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Christoph Mueller
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
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