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Melchior K, Gerner RR, Hossain S, Nuccio SP, Moreira CG, Raffatellu M. IL-22-dependent responses and their role during Citrobacter rodentium infection. Infect Immun 2024; 92:e0009924. [PMID: 38557196 PMCID: PMC11075456 DOI: 10.1128/iai.00099-24] [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: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/04/2024] Open
Abstract
The mouse pathogen Citrobacter rodentium is utilized as a model organism for studying infections caused by the human pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) and to elucidate mechanisms of mucosal immunity. In response to C. rodentium infection, innate lymphoid cells and T cells secrete interleukin (IL)-22, a cytokine that promotes mucosal barrier function. IL-22 plays a pivotal role in enabling mice to survive and recover from C. rodentium infection, although the exact mechanisms involved remain incompletely understood. Here, we investigated whether particular components of the host response downstream of IL-22 contribute to the cytokine's protective effects during C. rodentium infection. In line with previous research, mice lacking the IL-22 gene (Il22-/- mice) were highly susceptible to C. rodentium infection. To elucidate the role of specific antimicrobial proteins modulated by IL-22, we infected the following knockout mice: S100A9-/- (calprotectin), Lcn2-/- (lipocalin-2), Reg3b-/- (Reg3β), Reg3g-/- (Reg3γ), and C3-/- (C3). All knockout mice tested displayed a considerable level of resistance to C. rodentium infection, and none phenocopied the lethality observed in Il22-/- mice. By investigating another arm of the IL-22 response, we observed that C. rodentium-infected Il22-/- mice exhibited an overall decrease in gene expression related to intestinal barrier integrity as well as significantly elevated colonic inflammation, gut permeability, and pathogen levels in the spleen. Taken together, these results indicate that host resistance to lethal C. rodentium infection may depend on multiple antimicrobial responses acting in concert, or that other IL-22-regulated processes, such as tissue repair and maintenance of epithelial integrity, play crucial roles in host defense to attaching and effacing pathogens.
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Affiliation(s)
- Karine Melchior
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Romana R. Gerner
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- School of Life Sciences, ZIEL – Institute for Food and Health, Freising-Weihenstephan, Technical University of Munich, Munich, Germany
- Department of Internal Medicine III, University Hospital rechts der Isar, Technical University of Munich, Munich, Germany
| | - Suzana Hossain
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Sean-Paul Nuccio
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Cristiano Gallina Moreira
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Manuela Raffatellu
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, California, USA
- Chiba University-UC San Diego Center for Mucosal Immunology, Allergy, and Vaccines (CU-UCSD cMAV), La Jolla, California, USA
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Chen C, Xu J, Han T, Chen G, Yu K, Du C, Shen W, Sun Y, Zeng X. Microencapsulation as a Protective Strategy for Sialylated Immunoglobulin G: Efficacy in Alleviating Symptoms of Dextran Sulfate Sodium-Induced Colitis in Mice and Potential Mechanisms. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:4074-4088. [PMID: 38323407 DOI: 10.1021/acs.jafc.3c07733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Sialylated immunoglobulin G (IgG) is a vital glycoprotein in breast milk with the ability to promote the growth of Bifidobacterium in gut microbiota and relieve inflammatory bowel disease (IBD) symptoms in vitro. Here, it was found that the microcapsules with sialylated IgG could protect and release sialylated IgG with its structure and function in the intestine. Furthermore, the sialylated IgG microcapsules alleviated the clinical symptoms (body weight, feed quantity, and colon length loss), decreased disease activity index score, suppressed the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IFN-γ, and MCP-1) and endotoxin (lipopolysaccharide), and enhanced the intestinal mucosal barrier (Claudin1, Muc2, Occludin, and ZO-1) in dextran sulfate sodium (DSS)-induced colitis mice. Additionally, the sialylated IgG microcapsules improved the gut microbiota by increasing the relative abundance of critical microbe Bifidobacterium bifidum and promoted the production of short-chain fatty acids (SCFAs). Correlation analysis indicated that the key microbes were strongly correlated with pro-inflammatory factors, clinical symptoms, tight junction protein, and SCFAs. These findings suggest that the sialylated IgG microcapsules have the potential to be used as a novel therapeutic approach for treating IBD.
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Affiliation(s)
- Chunxu Chen
- College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui, China
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Jiaming Xu
- College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui, China
| | - Tianxiang Han
- College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui, China
| | - Guijie Chen
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Sciences & Technology, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Kun Yu
- College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui, China
| | - Chuanlai Du
- College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui, China
| | - Wenbiao Shen
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Yi Sun
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Xiaoxiong Zeng
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
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3
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Wu M, Zheng W, Song X, Bao B, Wang Y, Ramanan D, Yang D, Liu R, Macbeth JC, Do EA, Andrade WA, Yang T, Cho HS, Gazzaniga FS, Ilves M, Coronado D, Thompson C, Hang S, Chiu IM, Moffitt JR, Hsiao A, Mekalanos JJ, Benoist C, Kasper DL. Gut complement induced by the microbiota combats pathogens and spares commensals. Cell 2024; 187:897-913.e18. [PMID: 38280374 PMCID: PMC10922926 DOI: 10.1016/j.cell.2023.12.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 09/25/2023] [Accepted: 12/30/2023] [Indexed: 01/29/2024]
Abstract
Canonically, the complement system is known for its rapid response to remove microbes in the bloodstream. However, relatively little is known about a functioning complement system on intestinal mucosal surfaces. Herein, we report the local synthesis of complement component 3 (C3) in the gut, primarily by stromal cells. C3 is expressed upon commensal colonization and is regulated by the composition of the microbiota in healthy humans and mice, leading to an individual host's specific luminal C3 levels. The absence of membrane attack complex (MAC) components in the gut ensures that C3 deposition does not result in the lysis of commensals. Pathogen infection triggers the immune system to recruit neutrophils to the infection site for pathogen clearance. Basal C3 levels directly correlate with protection against enteric infection. Our study reveals the gut complement system as an innate immune mechanism acting as a vigilant sentinel that combats pathogens and spares commensals.
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Affiliation(s)
- Meng Wu
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Wen Zheng
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Xinyang Song
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Bin Bao
- Division of Gastroenterology, Boston Children's Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Yuanyou Wang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Deepshika Ramanan
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Daping Yang
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Rui Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521, USA
| | - John C Macbeth
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521, USA
| | - Elyza A Do
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521, USA
| | | | - Tiandi Yang
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Hyoung-Soo Cho
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Marit Ilves
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Daniela Coronado
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Saiyu Hang
- Genentech LLC, South San Francisco, CA 94080, USA
| | - Isaac M Chiu
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey R Moffitt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ansel Hsiao
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521, USA
| | - John J Mekalanos
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Dennis L Kasper
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA.
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Wu M, Zheng W, Song X, Bao B, Wang Y, Ramanan D, Yang D, Liu R, Macbeth JC, Do EA, Andrade WA, Yang T, Cho HS, Gazzaniga FS, Ilves M, Coronado D, Thompson C, Hang S, Chiu IM, Moffitt JR, Hsiao A, Mekalanos JJ, Benoist C, Kasper DL. Microbiome induced complement synthesized in the gut protects against enteric infections. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.523770. [PMID: 36778396 PMCID: PMC9915568 DOI: 10.1101/2023.02.02.523770] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Canonically, complement is a serum-based host defense system that protects against systemic microbial invasion. Little is known about the production and function of complement components on mucosal surfaces. Here we show gut complement component 3 (C3), central to complement function, is regulated by the composition of the microbiota in healthy humans and mice, leading to host-specific gut C3 levels. Stromal cells in intestinal lymphoid follicles (LFs) are the predominant source of intestinal C3. During enteric infection with Citrobacter rodentium or enterohemorrhagic Escherichia coli, luminal C3 levels increase significantly and are required for protection. C. rodentium is remarkably more invasive to the gut epithelium of C3-deficient mice than of wild-type mice. In the gut, C3-mediated phagocytosis of C. rodentium functions to clear pathogens. Our study reveals that variations in gut microbiota determine individuals’ intestinal mucosal C3 levels, dominantly produced by LF stromal cells, which directly correlate with protection against enteric infection. Highlights Gut complement component 3 (C3) is induced by the microbiome in healthy humans and mice at a microbiota-specific level.Gut stromal cells located in intestinal lymphoid follicles are a major source of luminal C3 During enteric infections with Citrobacter rodentium or enterohemorrhagic Escherichia coli, gut luminal C3 levels increase and are required for protection. C. rodentium is significantly more invasive of the gut epithelium in C3-deficient mice when compared to WT mice. In the gut, C3-mediated opsonophagocytosis of C. rodentium functions to clear pathogens.
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5
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Girinathan BP, DiBenedetto N, Worley JN, Peltier J, Arrieta-Ortiz ML, Immanuel SRC, Lavin R, Delaney ML, Cummins CK, Hoffman M, Luo Y, Gonzalez-Escalona N, Allard M, Onderdonk AB, Gerber GK, Sonenshein AL, Baliga NS, Dupuy B, Bry L. In vivo commensal control of Clostridioides difficile virulence. Cell Host Microbe 2021; 29:1693-1708.e7. [PMID: 34637781 DOI: 10.1016/j.chom.2021.09.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/26/2021] [Accepted: 09/16/2021] [Indexed: 12/23/2022]
Abstract
Leveraging systems biology approaches, we illustrate how metabolically distinct species of Clostridia protect against or worsen Clostridioides difficile infection in mice by modulating the pathogen's colonization, growth, and virulence to impact host survival. Gnotobiotic mice colonized with the amino acid fermenter Paraclostridium bifermentans survive infection with reduced disease severity, while mice colonized with the butyrate-producer, Clostridium sardiniense, succumb more rapidly. Systematic in vivo analyses revealed how each commensal alters the gut-nutrient environment to modulate the pathogen's metabolism, gene regulatory networks, and toxin production. Oral administration of P. bifermentans rescues conventional, clindamycin-treated mice from lethal C. difficile infection in a manner similar to that of monocolonized animals, thereby supporting the therapeutic potential of this commensal species. Our findings lay the foundation for mechanistically informed therapies to counter C. difficile disease using systems biology approaches to define host-commensal-pathogen interactions in vivo.
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Affiliation(s)
- Brintha P Girinathan
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nicholas DiBenedetto
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jay N Worley
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; National Center of Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, 25-28 Rue du Dr. Roux, Institut Pasteur, 75015 Paris Cedex, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-yvette Cedex, France
| | | | | | - Richard Lavin
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mary L Delaney
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Clinical Microbiology Laboratory, Department of Pathology, Brigham & Women's Hospital, Boston, MA 02115, USA
| | - Christopher K Cummins
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Maria Hoffman
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Microbiology, College Park, MD 20740, USA
| | - Yan Luo
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Microbiology, College Park, MD 20740, USA
| | - Narjol Gonzalez-Escalona
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Microbiology, College Park, MD 20740, USA
| | - Marc Allard
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Microbiology, College Park, MD 20740, USA
| | - Andrew B Onderdonk
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Clinical Microbiology Laboratory, Department of Pathology, Brigham & Women's Hospital, Boston, MA 02115, USA
| | - Georg K Gerber
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Health Sciences & Technology, Cambridge, MA 02139, USA
| | - Abraham L Sonenshein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | | | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, 25-28 Rue du Dr. Roux, Institut Pasteur, 75015 Paris Cedex, France
| | - Lynn Bry
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Clinical Microbiology Laboratory, Department of Pathology, Brigham & Women's Hospital, Boston, MA 02115, USA.
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6
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Chen C, Li T, Chen G, Chen D, Peng Y, Hu B, Sun Y, Zeng X. Commensal Relationship of Three Bifidobacterial Species Leads to Increase of Bifidobacterium in Vitro Fermentation of Sialylated Immunoglobulin G by Human Gut Microbiota. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9110-9119. [PMID: 32806107 DOI: 10.1021/acs.jafc.0c03628] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sialylated immunoglobulin G (IgG) is an important immunoglobulin in breast milk, but its effect on adult gut microbiota is not yet clear due to digestion by pepsin. Based on our previous IgG protecting study, effects of sialylated IgG on gut microbiota were investigated by in vitro anaerobic fermentation in the present study. It was found that the addition of sialylated IgG could significantly promote the growth of Bifidobacterium. Meanwhile, three bifidobacterial species B. bifidum CCX 19061, Bembidion breve CCX 19041, and B. longum subsp. infantis CCX 19042 were isolated. Furthermore, B. breve CCX 19041 and B. longum subsp. infantis CCX 19042 showed co-culture growth property with B. bifidum CCX 19061 in a sialylated IgG-based medium, which was also supported by changes of free monosaccharides and N-glycan structure. These findings suggest that the increase of Bifidobacterium in vitro fermentation is attributed to the commensal relationship of the three bifidobacterial species by utilizing sugars released from sialylated IgG.
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Affiliation(s)
- Chunxu Chen
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
- College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui, China
| | - Tianhui Li
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Guijie Chen
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Dan Chen
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Yujia Peng
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Bing Hu
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Yi Sun
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Xiaoxiong Zeng
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
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Amadou Amani S, Lang ML. Bacteria That Cause Enteric Diseases Stimulate Distinct Humoral Immune Responses. Front Immunol 2020; 11:565648. [PMID: 33042146 PMCID: PMC7524877 DOI: 10.3389/fimmu.2020.565648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/18/2020] [Indexed: 12/12/2022] Open
Abstract
Bacterial enteric pathogens individually and collectively represent a serious global health burden. Humoral immune responses following natural or experimentally-induced infections are broadly appreciated to contribute to pathogen clearance and prevention of disease recurrence. Herein, we have compared observations on humoral immune mechanisms following infection with Citrobacter rodentium, the model for enteropathogenic Escherichia coli, Vibrio cholerae, Shigella species, Salmonella enterica species, and Clostridioides difficile. A comparison of what is known about the humoral immune responses to these pathogens reveals considerable variance in specific features of humoral immunity including establishment of high affinity, IgG class-switched memory B cell and long-lived plasma cell compartments. This article suggests that such variance could be contributory to persistent and recurrent disease.
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Castro-Dopico T, Clatworthy MR. IgG and Fcγ Receptors in Intestinal Immunity and Inflammation. Front Immunol 2019; 10:805. [PMID: 31031776 PMCID: PMC6473071 DOI: 10.3389/fimmu.2019.00805] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/26/2019] [Indexed: 12/15/2022] Open
Abstract
Fcγ receptors (FcγR) are cell surface glycoproteins that mediate cellular effector functions of immunoglobulin G (IgG) antibodies. Genetic variation in FcγR genes can influence susceptibility to a variety of antibody-mediated autoimmune and inflammatory disorders, including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). More recently, however, genetic studies have implicated altered FcγR signaling in the pathogenesis of inflammatory bowel disease (IBD), a condition classically associated with dysregulated innate and T cell immunity. Specifically, a variant of the activating receptor, FcγRIIA, with low affinity for IgG, confers protection against the development of ulcerative colitis, a subset of IBD, leading to a re-evaluation of the role of IgG and FcγRs in gastrointestinal tract immunity, an organ system traditionally associated with IgA. In this review, we summarize our current understanding of IgG and FcγR function at this unique host-environment interface, from the pathogenesis of colitis and defense against enteropathogens, its contribution to maternal-fetal cross-talk and susceptibility to cancer. Finally, we discuss the therapeutic implications of this information, both in terms of how FcγR signaling pathways may be targeted for the treatment of IBD and how FcγR engagement may influence the efficacy of therapeutic monoclonal antibodies in IBD.
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Affiliation(s)
- Tomas Castro-Dopico
- Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Menna R. Clatworthy
- Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- NIHR Cambridge Biomedical Research CentreCambridge, United Kingdom
- Cellular Genetics, Wellcome Sanger Institute, Hinxton, United Kingdom
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Grizotte-Lake M, Zhong G, Duncan K, Kirkwood J, Iyer N, Smolenski I, Isoherranen N, Vaishnava S. Commensals Suppress Intestinal Epithelial Cell Retinoic Acid Synthesis to Regulate Interleukin-22 Activity and Prevent Microbial Dysbiosis. Immunity 2018; 49:1103-1115.e6. [PMID: 30566883 PMCID: PMC6319961 DOI: 10.1016/j.immuni.2018.11.018] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 08/13/2018] [Accepted: 11/26/2018] [Indexed: 12/16/2022]
Abstract
Retinoic acid (RA), a vitamin A metabolite, regulates transcriptional programs that drive protective or pathogenic immune responses in the intestine, in a manner dependent on RA concentration. Vitamin A is obtained from diet and is metabolized by intestinal epithelial cells (IECs), which operate in intimate association with microbes and immune cells. Here we found that commensal bacteria belonging to class Clostridia modulate RA concentration in the gut by suppressing the expression of retinol dehydrogenase 7 (Rdh7) in IECs. Rdh7 expression and associated RA amounts were lower in the intestinal tissue of conventional mice, as compared to germ-free mice. Deletion of Rdh7 in IECs diminished RA signaling in immune cells, reduced the IL-22-dependent antimicrobial response, and enhanced resistance to colonization by Salmonella Typhimurium. Our findings define a regulatory circuit wherein bacterial regulation of IEC-intrinsic RA synthesis protects microbial communities in the gut from excessive immune activity, achieving a balance that prevents colonization by enteric pathogens.
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Affiliation(s)
- Mayara Grizotte-Lake
- Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Guo Zhong
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA
| | - Kellyanne Duncan
- Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Jay Kirkwood
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA
| | - Namrata Iyer
- Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Irina Smolenski
- Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA
| | - Shipra Vaishnava
- Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA.
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10
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Chen C, Chen G, Wan P, Chen D, Zhu T, Hu B, Sun Y, Zeng X. Characterization of Bovine Serum Albumin and (-)-Epigallocatechin Gallate/3,4- O-Dicaffeoylquinic Acid/Tannic Acid Layer by Layer Assembled Microcapsule for Protecting Immunoglobulin G in Stomach Digestion and Release in Small Intestinal Tract. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:11141-11150. [PMID: 30277397 DOI: 10.1021/acs.jafc.8b04381] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The protein-polyphenol layer by layer (LbL) assembled polymer composite microcapsule is a considerable delivery system that can be used to improve the bioactive stability and effectiveness of natural compounds in various applications. In the present study, three kinds of polyphenols were loaded in the sequence of (-)-epigallocatechin gallate (EGCG), 3,4- O-dicaffeoylquinic acid (3,4-diCQA), and tannin acid (TA) to prepare a BSA-polyphenol LbL membrane. The composition of IgG-(BSA-EGCG/3,4-diCQA/TA) n microcapsules and their stability and releasing ability in the gastrointestinal tract were evaluated. In addition, by binding of these three kinds of polyphenols to BSA, the thermal denaturation temperature and ordered secondary structure of the BSA-polyphenol microcapsules were increased, and the time of scavenging activity on 2,2'-azinobis(3-ethylbenzothiazolin-6-sulfonic acid) free radicals was significantly prolonged. These findings suggest that (BSA-EGCG/3,4-diCQA/TA) n microcapsules can not only protect IgG in food processing and stomach digestion but also release it in the small intestinal tract for bioactive delivery.
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Affiliation(s)
- Chunxu Chen
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
- College of Food Engineering , Anhui Science and Technology University , Fengyang 233100 , Anhui , People's Republic of China
| | - Guijie Chen
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Peng Wan
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Dan Chen
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Tao Zhu
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , People's Republic of China
| | - Bing Hu
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Yi Sun
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Xiaoxiong Zeng
- College of Food Science and Technology , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
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Specialized Proresolving Mediators Rescue Infant Mice from Lethal Citrobacter rodentium Infection and Promote Immunity against Reinfection. Infect Immun 2017; 85:IAI.00464-17. [PMID: 28694292 DOI: 10.1128/iai.00464-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 06/29/2017] [Indexed: 02/06/2023] Open
Abstract
Infants are generally highly susceptible to oral pathogens. Intestinal infection and the associated diarrhea are significant global causes of morbidity and mortality in infants. Among the enteric pathogens, enteropathogenic Escherichia coli (EPEC) stands out as showing the highest risk for infection-induced death in infants ≤12 months old. We have developed an experimental model of infant infection with EPEC, using the mouse-specific pathogen Citrobacter rodentium Our murine infant model is similar to EPEC infection in human infants since infant mice are much more susceptible to C. rodentium infection than adult mice; infants infected with 50-fold fewer bacteria than the standard adult dose uniformly succumbed to the infection. Infant infection is characterized by high early and sustained bacterial titers and profound intestinal inflammation associated with extensive necrosis and systemic dissemination of the bacteria. Therefore, it seems likely that infant deaths result from sepsis secondary to intestinal damage. Recently, specialized proresolving mediators (SPM) have been found to exert profound beneficial effects in adult models of infection. Thus, we investigated the actions of two proresolving lipid mediators, resolvin D1 (RvD1) and resolvin D5 (RvD5), on the course of infection in infants. Strikingly, postinfection treatment with RvD1 and RvD5 reduced bacterial loads, mitigated inflammation, and rescued the infants from death. Furthermore, postinfection treatment with RvD1 and RvD5 led to protection from reinfection associated with C. rodentium-specific IgG responses comparable to those in adults. These results indicate that SPM may provide novel therapeutic tools for the treatment of pathological intestinal infections in infants.
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Citrobacter rodentium: a model enteropathogen for understanding the interplay of innate and adaptive components of type 3 immunity. Mucosal Immunol 2017; 10:1108-1117. [PMID: 28612839 PMCID: PMC5969517 DOI: 10.1038/mi.2017.47] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/13/2017] [Indexed: 02/07/2023]
Abstract
Citrobacter rodentium is a natural murine intestinal pathogen that shares a core set of virulence factors with the related human pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC). C. rodentium is now the most widely used small animal model for studying the molecular underpinnings of EPEC and EHEC infections in vivo, including: enterocyte attachment; virulence; colonization resistance; and mucosal immunity. In this review, we discuss type 3 immunity in the context of C. rodentium infection and discuss recent publications that use this model to understand how the innate and adaptive components of immunity intersect to mediate host protection against enteric pathogens and maintain homeostasis with the microbiota.
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Acuff NV, Li X, Elmore J, Rada B, Watford WT. Tpl2 promotes neutrophil trafficking, oxidative burst, and bacterial killing. J Leukoc Biol 2017; 101:1325-1333. [PMID: 28356348 DOI: 10.1189/jlb.3a0316-146r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 02/03/2017] [Accepted: 03/06/2017] [Indexed: 12/17/2022] Open
Abstract
Tumor progression locus 2 (Tpl2) is a serine/threonine kinase that promotes inflammatory cytokine production by activating the MEK/ERK pathway. Tpl2 has been shown to be important for eliciting the inflammatory properties of macrophages; however, there is relatively little known about the contribution of Tpl2 to neutrophil effector functions. This is an important consideration, as neutrophils provide the first line of defense against infection in the innate immune system. We found that Tpl2 is expressed in both human and murine neutrophils, suggesting a potential function for Tpl2 in this lineage. Despite significantly higher proportions of bone marrow (BM) neutrophils in Tpl2-deficient (Tpl2-/- ) mice compared with wild-type (WT) mice, Tpl2-/- mice have significantly reduced proportions of circulating neutrophils. Tpl2-/- neutrophils show impaired recruitment to thioglycollate, which was primarily a result of neutrophil-extrinsic factors in the host. In response to infection, neutrophils secrete inflammatory cytokines and produce reactive oxygen species (ROS), which promote bacterial killing. Tpl2 ablation impaired neutrophil TNF secretion in response to LPS stimulation, superoxide generation in response to the chemotactic peptide fMLP, and killing of the extracellular bacterium, Citrobacter rodentium, despite normal bacterial phagocytosis. These results implicate Tpl2 in the regulation of multiple neutrophil antimicrobial pathways, including inflammatory cytokine secretion and oxidative burst. Furthermore, they indicate that Tpl2 functions early during infection to bolster neutrophil-mediated innate immunity against extracellular bacteria.
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Affiliation(s)
- Nicole V Acuff
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Xin Li
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Jessica Elmore
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Balázs Rada
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Wendy T Watford
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
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Ottman N, Reunanen J, Meijerink M, Pietilä TE, Kainulainen V, Klievink J, Huuskonen L, Aalvink S, Skurnik M, Boeren S, Satokari R, Mercenier A, Palva A, Smidt H, de Vos WM, Belzer C. Pili-like proteins of Akkermansia muciniphila modulate host immune responses and gut barrier function. PLoS One 2017; 12:e0173004. [PMID: 28249045 PMCID: PMC5332112 DOI: 10.1371/journal.pone.0173004] [Citation(s) in RCA: 284] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/12/2017] [Indexed: 12/24/2022] Open
Abstract
Gut barrier function is key in maintaining a balanced response between the host and its microbiome. The microbiota can modulate changes in gut barrier as well as metabolic and inflammatory responses. This highly complex system involves numerous microbiota-derived factors. The gut symbiont Akkermansia muciniphila is positively correlated with a lean phenotype, reduced body weight gain, amelioration of metabolic responses and restoration of gut barrier function by modulation of mucus layer thickness. However, the molecular mechanisms behind its metabolic and immunological regulatory properties are unexplored. Herein, we identify a highly abundant outer membrane pili-like protein of A. muciniphila MucT that is directly involved in immune regulation and enhancement of trans-epithelial resistance. The purified Amuc_1100 protein and enrichments containing all its associated proteins induced production of specific cytokines through activation of Toll-like receptor (TLR) 2 and TLR4. This mainly leads to high levels of IL-10 similar to those induced by the other beneficial immune suppressive microorganisms such as Faecalibacterium prausnitzii A2-165 and Lactobacillus plantarum WCFS1. Together these results indicate that outer membrane protein composition and particularly the newly identified highly abundant pili-like protein Amuc_1100 of A. muciniphila are involved in host immunological homeostasis at the gut mucosa, and improvement of gut barrier function.
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Affiliation(s)
- Noora Ottman
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
- Department of Biosciences, University of Helsinki, Helsinki, Finland
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Justus Reunanen
- Cancer and Translational Medicine Research Unit, Biocenter Oulu and Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Marjolein Meijerink
- Host-Microbe Interactomics, Animal Sciences, Wageningen University, Wageningen, The Netherlands
- Department Risk Analysis for Products in Development, TNO, Zeist, the Netherlands
| | - Taija E. Pietilä
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Veera Kainulainen
- Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Judith Klievink
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
- Hematology Research Unit Helsinki, University of Helsinki and Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
| | - Laura Huuskonen
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Steven Aalvink
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Mikael Skurnik
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
- Helsinki University Central Hospital Laboratory Diagnostics, Helsinki, Finland
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands
| | - Reetta Satokari
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Annick Mercenier
- Host-Microbe Interactomics, Animal Sciences, Wageningen University, Wageningen, The Netherlands
| | - Airi Palva
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Willem M. de Vos
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Clara Belzer
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
- * E-mail:
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Abstract
The capsule from Bacteroides, a common gut symbiont, has long been a model system for studying the molecular mechanisms of host-symbiont interactions. The Bacteroides capsule is thought to consist of an array of phase-variable polysaccharides that give rise to subpopulations with distinct cell surface structures. Here, we report the serendipitous discovery of a previously unknown surface structure in Bacteroides thetaiotaomicron: a surface layer composed of a protein of unknown function, BT1927. BT1927, which is expressed in a phase-variable manner by ~1:1,000 cells in a wild-type culture, forms a hexagonally tessellated surface layer. The BT1927-expressing subpopulation is profoundly resistant to complement-mediated killing, due in part to the BT1927-mediated blockade of C3b deposition. Our results show that the Bacteroides surface structure is capable of a far greater degree of structural variation than previously known, and they suggest that structural variation within a Bacteroides species is important for productive gut colonization. Many bacterial species elaborate a capsule, a structure that resides outside the cell wall and mediates microbe-microbe and microbe-host interactions. Species of Bacteroides, the most abundant genus in the human gut, produce a capsule that consists of an array of polysaccharides, some of which are known to mediate interactions with the host immune system. Here, we report the discovery of a previously unknown surface structure in Bacteroides thetaiotaomicron. We show that this protein-based structure is expressed by a subset of cells in a population and protects Bacteroides from killing by complement, a component of the innate immune system. This novel surface layer protein is conserved across many species of the genus Bacteroides, suggesting an important role in colonization and host immune modulation.
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CD40 Ligand Deficient C57BL/6 Mouse Is a Potential Surrogate Model of Human X-Linked Hyper IgM (X-HIGM) Syndrome for Characterizing Immune Responses against Pathogens. BIOMED RESEARCH INTERNATIONAL 2015; 2015:679850. [PMID: 26064940 PMCID: PMC4433659 DOI: 10.1155/2015/679850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 12/10/2014] [Indexed: 01/12/2023]
Abstract
Individuals with X-HIGM syndrome fail to express functional CD40 ligand; consequently they cannot mount effective protective antibody responses against pathogenic bacteria. We evaluated, compared, and characterized the humoral immune response of wild type (WT) and C57-CD40L deficient (C57-CD40L−/−) mice infected with Citrobacter rodentium. Basal serum isotype levels were similar for IgM and IgG3 among mice, while total IgG and IgG2b concentrations were significantly lower in C57-CD40L−/− mice compared with WT. Essentially IgG1 and IgG2c levels were detectable only in WT mice. C57-CD40L−/− animals, orally inoculated with 2 × 109 CFU, presented several clinical manifestations since the second week of infection and eventually died. In contrast at this time point no clinical manifestations were observed among C57-CD40L−/− mice infected with 1 × 107 CFU. Infection was subclinical in WT mice inoculated with either bacterial dose. The serum samples from infected mice (1 × 107 CFU), collected at day 14 after infection, had similar C. rodentium-specific IgM titres. Although C57-CD40L−/− animals had lower IgG and IgG2b titres than WT mice, C57-CD40L−/− mice sera displayed complement-mediated bactericidal activity against C. rodentium. C. rodentium-infected C57-CD40L−/− mice are capable of producing antibodies that are protective. C57-CD40L−/− mouse is a useful surrogate model of X-HIGM syndrome for studying immune responses elicited against pathogens.
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Jain U, Cao Q, Thomas NA, Woodruff TM, Schwaeble WJ, Stover CM, Stadnyk AW. Properdin provides protection from Citrobacter rodentium-induced intestinal inflammation in a C5a/IL-6-dependent manner. THE JOURNAL OF IMMUNOLOGY 2015; 194:3414-21. [PMID: 25725105 DOI: 10.4049/jimmunol.1401814] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Citrobacter rodentium is an attaching and effacing mouse pathogen that models enteropathogenic and enterohemorrhagic Escherichia coli in humans. The complement system is an important innate defense mechanism; however, only scant information is available about the role of complement proteins during enteric infections. In this study, we examined the impact of the lack of properdin, a positive regulator of complement, in C. rodentium-induced colitis. Following infection, properdin knockout (P(KO)) mice had increased diarrhea and exacerbated inflammation combined with defective epithelial cell-derived IL-6 and greater numbers of colonizing bacteria. The defect in the mucosal response was reversed by administering exogenous properdin to P(KO) mice. Then, using in vitro and in vivo approaches, we show that the mechanism behind the exacerbated inflammation of P(KO) mice is due to a failure to increase local C5a levels. We show that C5a directly stimulates IL-6 production from colonic epithelial cells and that inhibiting C5a in infected wild-type mice resulted in defective epithelial IL-6 production and exacerbated inflammation. These outcomes position properdin early in the response to an infectious challenge in the colon, leading to complement activation and C5a, which in turn provides protection through IL-6 expression by the epithelium. Our results unveil a previously unappreciated mechanism of intestinal homeostasis involving complement, C5a, and IL-6 during bacteria-triggered epithelial injury.
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Affiliation(s)
- Umang Jain
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
| | - Qi Cao
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
| | - Nikhil A Thomas
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada; Department of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
| | - Trent M Woodruff
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Wilhelm J Schwaeble
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, United Kingdom; and
| | - Cordula M Stover
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, United Kingdom; and
| | - Andrew W Stadnyk
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada; Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
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18
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Rath T, Baker K, Pyzik M, Blumberg RS. Regulation of immune responses by the neonatal fc receptor and its therapeutic implications. Front Immunol 2015; 5:664. [PMID: 25601863 PMCID: PMC4283642 DOI: 10.3389/fimmu.2014.00664] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/10/2014] [Indexed: 11/13/2022] Open
Abstract
As a single receptor, the neonatal Fc receptor (FcRn) is critically involved in regulating albumin and IgG serum concentrations by protecting these two ligands from degradation. In addition to these essential homeostatic functions, FcRn possesses important functions in regulating immune responses that are equally as critical and are increasingly coming to attention. During the first stages of life, FcRn mediates the passive transfer of IgG across the maternal placenta or neonatal intestinal walls of mammals, thereby conferring passive immunity to the offspring before and after birth. In fact, FcRn is one of the very few molecules that are known to move from luminal to serosal membranes of polarized cells that form epithelial barriers of the lung and intestines. Together with FcRn's recently explored critical role in eliciting MHC II presentation and MHC class I cross-presentation of IgG-complexed antigen, this renders FcRn capable of exerting broad and potent functions in regulating immune responses and immunosurveillance at mucosal sites. Further, it is now clear that FcRn dependent mucosal absorption of therapeutic molecules is a clinically feasible and potent novel route of non-invasive drug delivery, and the interaction between FcRn and IgG has also been utilized for the acquisition of humoral immunity at mucosal sites. In this review, we begin by briefly summarizing the basic knowledge on FcRn expression and IgG binding, then describe more recent discoveries pertaining to the mechanisms by which FcRn orchestrates IgG related mucosal immune responses and immunosurveillance at host-environment interfaces within the adult organism. Finally, we outline how the knowledge of actions of FcRn at mucosal boundaries can be capitalized for the development and engineering of powerful mucosal vaccination strategies and novel routes for the non-invasive delivery of Fc-based therapeutics.
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Affiliation(s)
- Timo Rath
- Department of Medicine, Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Medicine, Division of Gastroenterology, Erlangen University Hospital, Friedrich Alexander University Erlangen-Nueremberg , Erlangen , Germany
| | - Kristi Baker
- Department of Medicine, Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA
| | - Michal Pyzik
- Department of Medicine, Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA
| | - Richard S Blumberg
- Department of Medicine, Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA ; Harvard Digestive Diseases Center , Boston, MA , USA
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Glycobiome: bacteria and mucus at the epithelial interface. Best Pract Res Clin Gastroenterol 2013; 27:25-38. [PMID: 23768550 DOI: 10.1016/j.bpg.2013.03.001] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 03/08/2013] [Indexed: 02/06/2023]
Abstract
The human gastrointestinal tract is colonised with a dense and diverse microbial community, that is an important player in human health and physiology. Close to the epithelial cells the mucosal microbiota is separated from the host with a thin lining of host derived glycans, including the cell surface glycocalyx and the extracellular secreted mucus. The mucosa-associated microbial composition differs from the luminal content and could be particularly important for nutrient exchange, communication with the host, development of the immune system, and resistance against invading pathogens. The mucosa-associated microbiota has adapted to the glycan rich environment by the production of mucus-degrading enzymes and mucus-binding extracellular proteins, and include mucus-degrading specialists such as Akkermansia muciniphila and Bacteroides thetaiotaomicron. This review is focussed on the host-microbe interactions within the glycan landscape at the epithelial interface and considers the spatial organisation and composition of the mucosa-associated microbiota in health and disease.
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