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van Gorp C, de Lange IH, Hütten MC, López-Iglesias C, Massy KRI, Kessels L, Knoops K, Cuijpers I, Sthijns MMJPE, Troost FJ, van Gemert WG, Spiller OB, Birchenough GMH, Zimmermann LJI, Wolfs TGAM. Antenatal Ureaplasma Infection Causes Colonic Mucus Barrier Defects: Implications for Intestinal Pathologies. Int J Mol Sci 2024; 25:4000. [PMID: 38612809 PMCID: PMC11011967 DOI: 10.3390/ijms25074000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/29/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024] Open
Abstract
Chorioamnionitis is a risk factor for necrotizing enterocolitis (NEC). Ureaplasma parvum (UP) is clinically the most isolated microorganism in chorioamnionitis, but its pathogenicity remains debated. Chorioamnionitis is associated with ileal barrier changes, but colonic barrier alterations, including those of the mucus barrier, remain under-investigated, despite their importance in NEC pathophysiology. Therefore, in this study, the hypothesis that antenatal UP exposure disturbs colonic mucus barrier integrity, thereby potentially contributing to NEC pathogenesis, was investigated. In an established ovine chorioamnionitis model, lambs were intra-amniotically exposed to UP or saline for 7 d from 122 to 129 d gestational age. Thereafter, colonic mucus layer thickness and functional integrity, underlying mechanisms, including endoplasmic reticulum (ER) stress and redox status, and cellular morphology by transmission electron microscopy were studied. The clinical significance of the experimental findings was verified by examining colon samples from NEC patients and controls. UP-exposed lambs have a thicker but dysfunctional colonic mucus layer in which bacteria-sized beads reach the intestinal epithelium, indicating undesired bacterial contact with the epithelium. This is paralleled by disturbed goblet cell MUC2 folding, pro-apoptotic ER stress and signs of mitochondrial dysfunction in the colonic epithelium. Importantly, the colonic epithelium from human NEC patients showed comparable mitochondrial aberrations, indicating that NEC-associated intestinal barrier injury already occurs during chorioamnionitis. This study underlines the pathogenic potential of UP during pregnancy; it demonstrates that antenatal UP infection leads to severe colonic mucus barrier deficits, providing a mechanistic link between antenatal infections and postnatal NEC development.
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Affiliation(s)
- Charlotte van Gorp
- Department of Pediatrics, School for Oncology and Reproduction (GROW), Maastricht University, 6229 ER Maastricht, The Netherlands; (C.v.G.); (M.C.H.); (K.R.I.M.); (L.K.); (L.J.I.Z.)
| | - Ilse H. de Lange
- Department of Pediatrics, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, 6229 ER Maastricht, The Netherlands;
| | - Matthias C. Hütten
- Department of Pediatrics, School for Oncology and Reproduction (GROW), Maastricht University, 6229 ER Maastricht, The Netherlands; (C.v.G.); (M.C.H.); (K.R.I.M.); (L.K.); (L.J.I.Z.)
- Neonatology, Department of Pediatrics, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Carmen López-Iglesias
- Microscopy CORE Lab, Maastricht Multimodal Molecular Imaging Institute (M4I), Maastricht University, 6211 LK Maastricht, The Netherlands; (C.L.-I.); (K.K.)
| | - Kimberly R. I. Massy
- Department of Pediatrics, School for Oncology and Reproduction (GROW), Maastricht University, 6229 ER Maastricht, The Netherlands; (C.v.G.); (M.C.H.); (K.R.I.M.); (L.K.); (L.J.I.Z.)
| | - Lilian Kessels
- Department of Pediatrics, School for Oncology and Reproduction (GROW), Maastricht University, 6229 ER Maastricht, The Netherlands; (C.v.G.); (M.C.H.); (K.R.I.M.); (L.K.); (L.J.I.Z.)
| | - Kèvin Knoops
- Microscopy CORE Lab, Maastricht Multimodal Molecular Imaging Institute (M4I), Maastricht University, 6211 LK Maastricht, The Netherlands; (C.L.-I.); (K.K.)
| | - Iris Cuijpers
- Food Innovation and Health, Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, 5911 BV Venlo, The Netherlands; (I.C.); (M.M.J.P.E.S.); (F.J.T.)
| | - Mireille M. J. P. E. Sthijns
- Food Innovation and Health, Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, 5911 BV Venlo, The Netherlands; (I.C.); (M.M.J.P.E.S.); (F.J.T.)
| | - Freddy J. Troost
- Food Innovation and Health, Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, 5911 BV Venlo, The Netherlands; (I.C.); (M.M.J.P.E.S.); (F.J.T.)
| | - Wim G. van Gemert
- Department of Surgery, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, 6229 ER Maastricht, The Netherlands;
| | - Owen B. Spiller
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XW, UK;
| | - George M. H. Birchenough
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden;
| | - Luc J. I. Zimmermann
- Department of Pediatrics, School for Oncology and Reproduction (GROW), Maastricht University, 6229 ER Maastricht, The Netherlands; (C.v.G.); (M.C.H.); (K.R.I.M.); (L.K.); (L.J.I.Z.)
| | - Tim G. A. M. Wolfs
- Department of Pediatrics, School for Oncology and Reproduction (GROW), Maastricht University, 6229 ER Maastricht, The Netherlands; (C.v.G.); (M.C.H.); (K.R.I.M.); (L.K.); (L.J.I.Z.)
- Department of Biomedical Engineering (BMT), School for Cardiovascular Diseases (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
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2
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Song R, McAlpine W, Fond AM, Nair-Gill E, Choi JH, Nyström EEL, Arike L, Field S, Li X, SoRelle JA, Moresco JJ, Moresco EMY, Yates JR, Azadi P, Ni J, Birchenough GMH, Beutler B, Turer EE. Trans-Golgi protein TVP23B regulates host-microbe interactions via Paneth cell homeostasis and Goblet cell glycosylation. Nat Commun 2023; 14:3652. [PMID: 37339972 PMCID: PMC10282085 DOI: 10.1038/s41467-023-39398-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 06/09/2023] [Indexed: 06/22/2023] Open
Abstract
A key feature in intestinal immunity is the dynamic intestinal barrier, which separates the host from resident and pathogenic microbiota through a mucus gel impregnated with antimicrobial peptides. Using a forward genetic screen, we have found a mutation in Tvp23b, which conferred susceptibility to chemically induced and infectious colitis. Trans-Golgi apparatus membrane protein TVP23 homolog B (TVP23B) is a transmembrane protein conserved from yeast to humans. We found that TVP23B controls the homeostasis of Paneth cells and function of goblet cells, leading to a decrease in antimicrobial peptides and more penetrable mucus layer. TVP23B binds with another Golgi protein, YIPF6, which is similarly critical for intestinal homeostasis. The Golgi proteomes of YIPF6 and TVP23B-deficient colonocytes have a common deficiency of several critical glycosylation enzymes. TVP23B is necessary for the formation of the sterile mucin layer of the intestine and its absence disturbs the balance of host and microbe in vivo.
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Affiliation(s)
- Ran Song
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - William McAlpine
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Aaron M Fond
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Evan Nair-Gill
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Jin Huk Choi
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Elisabeth E L Nyström
- Institute of Biochemistry, University of Kiel, 24118, Kiel, Schleswig-Holstein, Germany
| | - Liisa Arike
- The Wallenberg Centre for Molecular & Translational Medicine, Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Sydney Field
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Xiaohong Li
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Jeffrey A SoRelle
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - James J Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Josephine Ni
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - George M H Birchenough
- The Wallenberg Centre for Molecular & Translational Medicine, Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Emre E Turer
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA.
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA.
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3
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Birchenough GMH, Schroeder BO, Sharba S, Arike L, Recktenwald CV, Puértolas-Balint F, Subramani MV, Hansson KT, Yilmaz B, Lindén SK, Bäckhed F, Hansson GC. Muc2-dependent microbial colonization of the jejunal mucus layer is diet sensitive and confers local resistance to enteric pathogen infection. Cell Rep 2023; 42:112084. [PMID: 36753416 PMCID: PMC10404306 DOI: 10.1016/j.celrep.2023.112084] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/12/2022] [Accepted: 01/23/2023] [Indexed: 02/09/2023] Open
Abstract
Intestinal mucus barriers normally prevent microbial infections but are sensitive to diet-dependent changes in the luminal environment. Here we demonstrate that mice fed a Western-style diet (WSD) suffer regiospecific failure of the mucus barrier in the small intestinal jejunum caused by diet-induced mucus aggregation. Mucus barrier disruption due to either WSD exposure or chromosomal Muc2 deletion results in collapse of the commensal jejunal microbiota, which in turn sensitizes mice to atypical jejunal colonization by the enteric pathogen Citrobacter rodentium. We illustrate the jejunal mucus layer as a microbial habitat, and link the regiospecific mucus dependency of the microbiota to distinctive properties of the jejunal niche. Together, our data demonstrate a symbiotic mucus-microbiota relationship that normally prevents jejunal pathogen colonization, but is highly sensitive to disruption by exposure to a WSD.
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Affiliation(s)
- George M H Birchenough
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden; Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden.
| | - Bjoern O Schroeder
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden; Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Sinan Sharba
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Liisa Arike
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Christian V Recktenwald
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Fabiola Puértolas-Balint
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Mahadevan V Subramani
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden; Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Karl T Hansson
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden; Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Bahtiyar Yilmaz
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Sara K Lindén
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Fredrik Bäckhed
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Gunnar C Hansson
- Department of Medical Biochemistry & Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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4
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Nyström EEL, Martinez-Abad B, Arike L, Birchenough GMH, Nonnecke EB, Castillo PA, Svensson F, Bevins CL, Hansson GC, Johansson MEV. An intercrypt subpopulation of goblet cells is essential for colonic mucus barrier function. Science 2021; 372:372/6539/eabb1590. [PMID: 33859001 DOI: 10.1126/science.abb1590] [Citation(s) in RCA: 116] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 03/05/2021] [Indexed: 12/11/2022]
Abstract
The intestinal mucus layer, an important element of epithelial protection, is produced by goblet cells. Intestinal goblet cells are assumed to be a homogeneous cell type. In this study, however, we delineated their specific gene and protein expression profiles and identified several distinct goblet cell populations that form two differentiation trajectories. One distinct subtype, the intercrypt goblet cells (icGCs), located at the colonic luminal surface, produced mucus with properties that differed from the mucus secreted by crypt-residing goblet cells. Mice with defective icGCs had increased sensitivity to chemically induced colitis and manifested spontaneous colitis with age. Furthermore, alterations in mucus and reduced numbers of icGCs were observed in patients with both active and remissive ulcerative colitis, which highlights the importance of icGCs in maintaining functional protection of the epithelium.
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Affiliation(s)
- Elisabeth E L Nyström
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Beatriz Martinez-Abad
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Liisa Arike
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - George M H Birchenough
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Eric B Nonnecke
- Department of Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA
| | - Patricia A Castillo
- Department of Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA
| | - Frida Svensson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Charles L Bevins
- Department of Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA
| | - Gunnar C Hansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Malin E V Johansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden.
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5
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van der Post S, Birchenough GMH, Held JM. NOX1-dependent redox signaling potentiates colonic stem cell proliferation to adapt to the intestinal microbiota by linking EGFR and TLR activation. Cell Rep 2021; 35:108949. [PMID: 33826887 PMCID: PMC10327654 DOI: 10.1016/j.celrep.2021.108949] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 01/25/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
The colon epithelium is a primary point of interaction with the microbiome and is regenerated by a few rapidly cycling colonic stem cells (CSCs). CSC self-renewal and proliferation are regulated by growth factors and the presence of bacteria. However, the molecular link connecting the diverse inputs that maintain CSC homeostasis remains largely unknown. We report that CSC proliferation is mediated by redox-dependent activation of epidermal growth factor receptor (EGFR) signaling via NADPH oxidase 1 (NOX1). NOX1 expression is CSC specific and is restricted to proliferative CSCs. In the absence of NOX1, CSCs fail to generate ROS and have a reduced proliferation rate. NOX1 expression is regulated by Toll-like receptor activation in response to the microbiota and serves to link CSC proliferation with the presence of bacterial components in the crypt. The TLR-NOX1-EGFR axis is therefore a critical redox signaling node in CSCs facilitating the quiescent-proliferation transition and responds to the microbiome to maintain colon homeostasis.
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Affiliation(s)
- Sjoerd van der Post
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - George M H Birchenough
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Jason M Held
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; Siteman Cancer Center, Washington University School of Medicine in St. Louis, St. Louis, MO, USA.
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6
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Schroeder BO, Birchenough GMH, Pradhan M, Nyström EEL, Henricsson M, Hansson GC, Bäckhed F. Obesity-associated microbiota contributes to mucus layer defects in genetically obese mice. J Biol Chem 2020; 295:15712-15726. [PMID: 32900852 PMCID: PMC7667970 DOI: 10.1074/jbc.ra120.015771] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/04/2020] [Indexed: 12/12/2022] Open
Abstract
The intestinal mucus layer is a physical barrier separating the tremendous number of gut bacteria from the host epithelium. Defects in the mucus layer have been linked to metabolic diseases, but previous studies predominantly investigated mucus function during high-caloric/low-fiber dietary interventions, thus making it difficult to separate effects mediated directly through diet quality from potential obesity-dependent effects. As such, we decided to examine mucus function in mouse models with metabolic disease to distinguish these factors. Here we show that, in contrast to their lean littermates, genetically obese (ob/ob) mice have a defective inner colonic mucus layer that is characterized by increased penetrability and a reduced mucus growth rate. Exploiting the coprophagic behavior of mice, we next co-housed ob/ob and lean mice to investigate if the gut microbiota contributed to these phenotypes. Co-housing rescued the defect of the mucus growth rate, whereas mucus penetrability displayed an intermediate phenotype in both mouse groups. Of note, non-obese diabetic mice with high blood glucose levels displayed a healthy colonic mucus barrier, indicating that the mucus defect is obesity- rather than glucose-mediated. Thus, our data suggest that the gut microbiota community of obesity-prone mice may regulate obesity-associated defects in the colonic mucosal barrier, even in the presence of dietary fiber.
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Affiliation(s)
- Bjoern O Schroeder
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden; Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden.
| | - George M H Birchenough
- Department of Medical BiochemistryInstitute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Meenakshi Pradhan
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Elisabeth E L Nyström
- Department of Medical BiochemistryInstitute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Marcus Henricsson
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Gunnar C Hansson
- Department of Medical BiochemistryInstitute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Fredrik Bäckhed
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Physiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
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7
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Affiliation(s)
| | - Malin E. V. Johansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Sweden
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8
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Volk JK, Nyström EEL, van der Post S, Abad BM, Schroeder BO, Johansson Å, Svensson F, Jäverfelt S, Johansson MEV, Hansson GC, Birchenough GMH. The Nlrp6 inflammasome is not required for baseline colonic inner mucus layer formation or function. J Exp Med 2019; 216:2602-2618. [PMID: 31420376 PMCID: PMC6829596 DOI: 10.1084/jem.20190679] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/06/2019] [Accepted: 07/22/2019] [Indexed: 12/26/2022] Open
Abstract
It is thought that the Nlrp6 inflammasome regulates formation of the inner mucus layer (IML) barrier that prohibits contact between the microbiota and colonic epithelial cells. Using microbiota-controlled mice and combined ex vivo/in vivo IML analytical approaches, Volk et al. delineate the relative roles of the inflammasome and microbiota in shaping IML formation and function. The inner mucus layer (IML) is a critical barrier that protects the colonic epithelium from luminal threats and inflammatory bowel disease. Innate immune signaling is thought to regulate IML formation via goblet cell Nlrp6 inflammasome activity that controls secretion of the mucus structural component Muc2. We report that isolated colonic goblet cells express components of several inflammasomes; however, analysis of IML properties in multiple inflammasome-deficient mice, including littermate-controlled Nlrp6−/−, detect a functional IML barrier in all strains. Analysis of mice lacking inflammasome substrate cytokines identifies a defective IML in Il18−/− mice, but this phenotype is ultimately traced to a microbiota-driven, Il18-independent effect. Analysis of phenotypic transfer between IML-deficient and IML-intact mice finds that the Bacteroidales family S24-7 (Muribaculaceae) and genus Adlercrutzia consistently positively covary with IML barrier function. Together, our results demonstrate that baseline IML formation and function is independent of inflammasome activity and highlights the role of the microbiota in determining IML barrier function.
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Affiliation(s)
- Joana K Volk
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Elisabeth E L Nyström
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Sjoerd van der Post
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Beatriz M Abad
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Bjoern O Schroeder
- Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Åsa Johansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Frida Svensson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Sofia Jäverfelt
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Malin E V Johansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Gunnar C Hansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - George M H Birchenough
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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9
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Nyström EEL, Birchenough GMH, van der Post S, Arike L, Gruber AD, Hansson GC, Johansson MEV. Calcium-activated Chloride Channel Regulator 1 (CLCA1) Controls Mucus Expansion in Colon by Proteolytic Activity. EBioMedicine 2018; 33:134-143. [PMID: 29885864 PMCID: PMC6085540 DOI: 10.1016/j.ebiom.2018.05.031] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 12/12/2022] Open
Abstract
Many epithelial surfaces of the body are covered with protective mucus, and disrupted mucus homeostasis is coupled to diseases such as ulcerative colitis, helminth infection, cystic fibrosis, and chronic obstructive lung disease. However, little is known how a balanced mucus system is maintained. By investigating the involvement of proteases in colonic mucus dynamics we identified metalloprotease activity to be a key contributor to mucus expansion. The effect was mediated by calcium-activated chloride channel regulator 1 (CLCA1) as application of recombinant CLCA1 on intestinal mucus in freshly dissected tissue resulted in increased mucus thickness independently of ion and mucus secretion, but dependent on its metallohydrolase activity. Further, CLCA1 modulated mucus dynamics in both human and mouse, and knock-out of CLCA1 in mice was compensated for by cysteine proteases. Our results suggest that CLCA1 is involved in intestinal mucus homeostasis by facilitating processing and removal of mucus to prevent stagnation. In light of our findings, we suggest future studies to investigate if upregulation of CLCA1 in diseases associated with mucus accumulation could facilitate removal of mucus in an attempt to maintain homeostasis. Endogenous metalloprotease activity is important for intestinal mucus dynamics. CLCA1 acts as a metalloprotease in intestinal mucus and this function is independent of ion and mucus secretion. CLCA1 is involved in the transition from the inner to outer mucus layer in colon.
In this article we provide evidence that endogenous enzyme activity is important for normal processing of the intestinal mucus layer, which creates a protective barrier against the vast number of bacteria in the large intestine. CLCA1, a highly abundant intestinal mucus protein, seems to be a key contributor to mucus processing. This role for CLCA1 is different from what was previously described. As mucus clearance is of importance for several diseases, better understanding of mucus processing could be of great importance to develop new therapies.
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Affiliation(s)
- Elisabeth E L Nyström
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - George M H Birchenough
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Sjoerd van der Post
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Liisa Arike
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Achim D Gruber
- Department of Veterinary Pathology, Freie Universität Berlin, Germany
| | - Gunnar C Hansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Malin E V Johansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530 Gothenburg, Sweden.
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10
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Schroeder BO, Birchenough GMH, Ståhlman M, Arike L, Johansson MEV, Hansson GC, Bäckhed F. Bifidobacteria or Fiber Protects against Diet-Induced Microbiota-Mediated Colonic Mucus Deterioration. Cell Host Microbe 2017; 23:27-40.e7. [PMID: 29276171 DOI: 10.1016/j.chom.2017.11.004] [Citation(s) in RCA: 417] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/14/2017] [Accepted: 10/20/2017] [Indexed: 12/18/2022]
Abstract
Diet strongly affects gut microbiota composition, and gut bacteria can influence the colonic mucus layer, a physical barrier that separates trillions of gut bacteria from the host. However, the interplay between a Western style diet (WSD), gut microbiota composition, and the intestinal mucus layer is less clear. Here we show that mice fed a WSD have an altered colonic microbiota composition that causes increased penetrability and a reduced growth rate of the inner mucus layer. Both barrier defects can be prevented by transplanting microbiota from chow-fed mice. In addition, we found that administration of Bifidobacterium longum was sufficient to restore mucus growth, whereas administration of the fiber inulin prevented increased mucus penetrability in WSD-fed mice. We hypothesize that the presence of distinct bacteria is crucial for proper mucus function. If confirmed in humans, these findings may help to better understand diseases with an affected mucus layer, such as ulcerative colitis.
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Affiliation(s)
- Bjoern O Schroeder
- Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - George M H Birchenough
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Marcus Ståhlman
- Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Liisa Arike
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Malin E V Johansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Gunnar C Hansson
- Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden.
| | - Fredrik Bäckhed
- Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, 405 30 Gothenburg, Sweden; Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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11
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Birchenough GMH, Dalgakiran F, Witcomb LA, Johansson MEV, McCarthy AJ, Hansson GC, Taylor PW. Postnatal development of the small intestinal mucosa drives age-dependent, regio-selective susceptibility to Escherichia coli K1 infection. Sci Rep 2017; 7:83. [PMID: 28250440 PMCID: PMC5427930 DOI: 10.1038/s41598-017-00123-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/08/2017] [Indexed: 12/22/2022] Open
Abstract
The strong age dependency of neonatal systemic infection with Escherichia coli K1 can be replicated in the neonatal rat. Gastrointestinal (GI) colonization of two-day-old (P2) rats leads to invasion of the blood within 48 h of initiation of colonization; pups become progressively less susceptible to infection over the P2-P9 period. We show that, in animals colonized at P2 but not at P9, E. coli K1 bacteria gain access to the enterocyte surface in the mid-region of the small intestine and translocate through the epithelial cell monolayer by an intracellular pathway to the submucosa. In this region of the GI tract, the protective mucus barrier is poorly developed but matures to full thickness over P2-P9, coincident with the development of resistance to invasion. At P9, E. coli K1 bacteria are physically separated from villi by the mucus layer and their numbers controlled by mucus-embedded antimicrobial peptides, preventing invasion of host tissues.
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Affiliation(s)
- George M H Birchenough
- Department of Medical Biochemistry, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Fatma Dalgakiran
- School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Luci A Witcomb
- School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Malin E V Johansson
- Department of Medical Biochemistry, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Alex J McCarthy
- School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Gunnar C Hansson
- Department of Medical Biochemistry, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Peter W Taylor
- School of Pharmacy, University College London, London, WC1N 1AX, UK.
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12
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Bosmans JWAM, Jongen ACHM, Birchenough GMH, Nyström EEL, Gijbels MJJ, Derikx JPM, Bouvy ND, Hansson GC. Functional mucous layer and healing of proximal colonic anastomoses in an experimental model. Br J Surg 2017; 104:619-630. [PMID: 28195642 DOI: 10.1002/bjs.10456] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/14/2016] [Accepted: 11/09/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Anastomotic leakage (AL) is the most dreaded complication after colorectal surgery, causing high morbidity and mortality. Mucus is a first line of defence against external factors in the gastrointestinal tract. In this study, the structural mucus protein Muc2 was depleted in genetically engineered mice and the effect on healing of colonic anastomoses studied in an experimental model. METHODS Mice of different Muc2 genotypes were used in a proximal colonic AL model. Tissues were scored histologically for inflammation, bacterial translocation was determined by quantitative PCR of bacterial 16S ribosomal DNA, and epithelial cell damage was determined by assessing serum levels of intestinal fatty acid-binding protein. RESULTS Of 22 Muc2-deficient (Muc2-/- ) mice, 20 developed AL, compared with seven of 22 control animals (P < 0·001). Control mice showed normal healing, whereas Muc2-/- mice had more inflammation with less collagen deposition and neoangiogenesis. A tendency towards higher bacterial translocation was seen in mesenteric lymph nodes and spleen in Muc2-/- mice. Intestinal fatty acid-binding protein levels were significantly higher in Muc2-/- mice compared with controls (P = 0·011). CONCLUSION A functional mucous layer facilitates the healing of colonic anastomoses. Clinical relevance Colorectal anastomotic leakage remains the most dreaded complication after colorectal surgery. It is known that the aetiology of anastomotic leakage is multifactorial, and a role is suggested for the interaction between intraluminal content and mucosa. In this murine model of proximal colonic anastomotic leakage, the authors investigated the mucous layer at the intestinal mucosa, as the first line of defence, and found that a normal, functioning mucous layer is essential in the healing process of colonic anastomoses. Further research on anastomotic healing should focus on positively influencing the mucous layer to promote better postoperative recovery.
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Affiliation(s)
- J W A M Bosmans
- Department of Surgery, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht, The Netherlands
| | - A C H M Jongen
- Department of Surgery, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht, The Netherlands
| | - G M H Birchenough
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - E E L Nyström
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - M J J Gijbels
- Departments of Pathology and Molecular Genetics, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Centre, Maastricht, The Netherlands.,Experimental Vascular Biology, Department of Medical Biochemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - J P M Derikx
- Department of Surgery, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht, The Netherlands.,Paediatric Surgical Centre Amsterdam, Emma Children's Hospital/VU University Medical Centre, Amsterdam, The Netherlands
| | - N D Bouvy
- Department of Surgery, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht, The Netherlands
| | - G C Hansson
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
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13
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Birchenough GMH, Nyström EEL, Johansson MEV, Hansson GC. A sentinel goblet cell guards the colonic crypt by triggering Nlrp6-dependent Muc2 secretion. Science 2016; 352:1535-42. [PMID: 27339979 DOI: 10.1126/science.aaf7419] [Citation(s) in RCA: 362] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/16/2016] [Indexed: 12/18/2022]
Abstract
Innate immune signaling pathways contribute to the protection of host tissue when bacterially challenged. Colonic goblet cells are responsible for generating the two mucus layers that physically separate the luminal microbiota from the host epithelium. Analysis of colonic tissues from multiple mouse strains allowed us to identify a "sentinel" goblet cell (senGC) localized to the colonic crypt entrance. This cell nonspecifically endocytoses and reacts to the TLR2/1, TLR4, and TLR5 ligands by activating the Nlrp6 inflammasome downstream of TLR- and MyD88-dependent Nox/Duox reactive oxygen species synthesis. This triggers calcium ion-dependent compound exocytosis of Muc2 mucin from the senGC and generates an intercellular gap junction signal; in turn, this signal induces Muc2 secretion from adjacent goblet cells in the upper crypt, which expels bacteria. Thus, senGCs guard and protect the colonic crypt from bacterial intruders that have penetrated the inner mucus layer.
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Affiliation(s)
| | - Elisabeth E L Nyström
- Department of Medical Biochemistry, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Malin E V Johansson
- Department of Medical Biochemistry, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Gunnar C Hansson
- Department of Medical Biochemistry, University of Gothenburg, 40530 Gothenburg, Sweden.
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14
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Erickson NA, Nyström EEL, Mundhenk L, Arike L, Glauben R, Heimesaat MM, Fischer A, Bereswill S, Birchenough GMH, Gruber AD, Johansson MEV. The Goblet Cell Protein Clca1 (Alias mClca3 or Gob-5) Is Not Required for Intestinal Mucus Synthesis, Structure and Barrier Function in Naive or DSS-Challenged Mice. PLoS One 2015; 10:e0131991. [PMID: 26162072 PMCID: PMC4498832 DOI: 10.1371/journal.pone.0131991] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/09/2015] [Indexed: 12/15/2022] Open
Abstract
The secreted, goblet cell-derived protein Clca1 (chloride channel regulator, calcium-activated-1) has been linked to diseases with mucus overproduction, including asthma and cystic fibrosis. In the intestine Clca1 is found in the mucus with an abundance and expression pattern similar to Muc2, the major structural mucus component. We hypothesized that Clca1 is required for the synthesis, structure or barrier function of intestinal mucus and therefore compared wild type and Clca1-deficient mice under naive and at various time points of DSS (dextran sodium sulfate)-challenged conditions. The mucus phenotype in Clca1-deficient compared to wild type mice was systematically characterized by assessment of the mucus protein composition using proteomics, immunofluorescence and expression analysis of selected mucin genes on mRNA level. Mucus barrier integrity was assessed in-vivo by analysis of bacterial penetration into the mucus and translocation into sentinel organs combined analysis of the fecal microbiota and ex-vivo by assessment of mucus penetrability using beads. All of these assays revealed no relevant differences between wild type and Clca1-deficient mice under steady state or DSS-challenged conditions in mouse colon. Clca1 is not required for mucus synthesis, structure and barrier function in the murine colon.
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Affiliation(s)
- Nancy A. Erickson
- Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
| | | | - Lars Mundhenk
- Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
| | - Liisa Arike
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Rainer Glauben
- Medical Department, Division of Gastroenterology, Infectiology and Rheumatology—Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Markus M. Heimesaat
- Department of Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - André Fischer
- Department of Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stefan Bereswill
- Department of Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Achim D. Gruber
- Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
| | - Malin E. V. Johansson
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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15
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Birchenough GMH, Johansson MEV, Gustafsson JK, Bergström JH, Hansson GC. New developments in goblet cell mucus secretion and function. Mucosal Immunol 2015; 8:712-9. [PMID: 25872481 PMCID: PMC4631840 DOI: 10.1038/mi.2015.32] [Citation(s) in RCA: 459] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/20/2015] [Indexed: 02/06/2023]
Abstract
Goblet cells and their main secretory product, mucus, have long been poorly appreciated; however, recent discoveries have changed this and placed these cells at the center stage of our understanding of mucosal biology and the immunology of the intestinal tract. The mucus system differs substantially between the small and large intestine, although it is built around MUC2 mucin polymers in both cases. Furthermore, that goblet cells and the regulation of their secretion also differ between these two parts of the intestine is of fundamental importance for a better understanding of mucosal immunology. There are several types of goblet cell that can be delineated based on their location and function. The surface colonic goblet cells secrete continuously to maintain the inner mucus layer, whereas goblet cells of the colonic and small intestinal crypts secrete upon stimulation, for example, after endocytosis or in response to acetyl choline. However, despite much progress in recent years, our understanding of goblet cell function and regulation is still in its infancy.
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Affiliation(s)
- G M H Birchenough
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - M E V Johansson
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - J K Gustafsson
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - J H Bergström
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - G C Hansson
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
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16
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Pelaseyed T, Bergström JH, Gustafsson JK, Ermund A, Birchenough GMH, Schütte A, van der Post S, Svensson F, Rodríguez-Piñeiro AM, Nyström EEL, Wising C, Johansson MEV, Hansson GC. The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system. Immunol Rev 2015; 260:8-20. [PMID: 24942678 DOI: 10.1111/imr.12182] [Citation(s) in RCA: 750] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The gastrointestinal tract is covered by mucus that has different properties in the stomach, small intestine, and colon. The large highly glycosylated gel-forming mucins MUC2 and MUC5AC are the major components of the mucus in the intestine and stomach, respectively. In the small intestine, mucus limits the number of bacteria that can reach the epithelium and the Peyer's patches. In the large intestine, the inner mucus layer separates the commensal bacteria from the host epithelium. The outer colonic mucus layer is the natural habitat for the commensal bacteria. The intestinal goblet cells secrete not only the MUC2 mucin but also a number of typical mucus components: CLCA1, FCGBP, AGR2, ZG16, and TFF3. The goblet cells have recently been shown to have a novel gate-keeping role for the presentation of oral antigens to the immune system. Goblet cells deliver small intestinal luminal material to the lamina propria dendritic cells of the tolerogenic CD103(+) type. In addition to the gel-forming mucins, the transmembrane mucins MUC3, MUC12, and MUC17 form the enterocyte glycocalyx that can reach about a micrometer out from the brush border. The MUC17 mucin can shuttle from a surface to an intracellular vesicle localization, suggesting that enterocytes might control and report epithelial microbial challenge. There is communication not only from the epithelial cells to the immune system but also in the opposite direction. One example of this is IL10 that can affect and improve the properties of the inner colonic mucus layer. The mucus and epithelial cells of the gastrointestinal tract are the primary gate keepers and controllers of bacterial interactions with the host immune system, but our understanding of this relationship is still in its infancy.
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Affiliation(s)
- Thaher Pelaseyed
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
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Abstract
Investigation of the interactions between animal host and bacterial pathogen is only meaningful if the infection model employed replicates the principal features of the natural infection. This protocol describes procedures for the establishment and evaluation of systemic infection due to neuropathogenic Escherichia coli K1 in the neonatal rat. Colonization of the gastrointestinal tract leads to dissemination of the pathogen along the gut-lymph-blood-brain course of infection and the model displays strong age dependency. A strain of E. coli O18:K1 with enhanced virulence for the neonatal rat produces exceptionally high rates of colonization, translocation to the blood compartment and invasion of the meninges following transit through the choroid plexus. As in the human host, penetration of the central nervous system is accompanied by local inflammation and an invariably lethal outcome. The model is of proven utility for studies of the mechanism of pathogenesis, for evaluation of therapeutic interventions and for assessment of bacterial virulence.
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18
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Birchenough GMH, Johansson MEV, Stabler RA, Dalgakiran F, Hansson GC, Wren BW, Luzio JP, Taylor PW. Altered innate defenses in the neonatal gastrointestinal tract in response to colonization by neuropathogenic Escherichia coli. Infect Immun 2013; 81:3264-75. [PMID: 23798529 PMCID: PMC3754193 DOI: 10.1128/iai.00268-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 06/14/2013] [Indexed: 01/06/2023] Open
Abstract
Two-day-old (P2), but not 9-day-old (P9), rat pups are susceptible to systemic infection following gastrointestinal colonization by Escherichia coli K1. Age dependency reflects the capacity of colonizing K1 to translocate from gastrointestinal (GI) tract to blood. A complex GI microbiota developed by P2, showed little variation over P2 to P9, and did not prevent stable K1 colonization. Substantial developmental expression was observed over P2 to P9, including upregulation of genes encoding components of the small intestinal (α-defensins Defa24 and Defa-rs1) and colonic (trefoil factor Tff2) mucus barrier. K1 colonization modulated expression of these peptides: developmental expression of Tff2 was dysregulated in P2 tissues and was accompanied by a decrease in mucin Muc2. Conversely, α-defensin genes were upregulated in P9 tissues. We propose that incomplete development of the mucus barrier during early neonatal life and the capacity of colonizing K1 to interfere with mucus barrier maturation provide opportunities for neuropathogen translocation into the bloodstream.
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Affiliation(s)
| | | | | | - Fatma Dalgakiran
- University College London School of Pharmacy, London, United Kingdom
| | | | - Brendan W. Wren
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - J. Paul Luzio
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Peter W. Taylor
- University College London School of Pharmacy, London, United Kingdom
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